text:
|Publication number
|Publication type
|Publication date
|Feb 25, 1969
|Filing date
|May 25, 1965
|Priority date
|May 25, 1965
|Also published as
|Publication number
|Bauer William V, Sze Morgan C
|Original Assignee
|Lummus Co
|Export Citation
|BiBTeX, EndNote, RefMan
|Patent Citations (3), Referenced by (13), Classifications (15)
|External Links: USPTO, USPTO Assignment, Espacenet
Feb. 25, 1969 c. SZE ET Al.
TWO-STAGE HYDROTREATING OF DRIPOLENE Filed May 25. 1965 R mm vu/ am 5 A V- mm R 3 mm nn/ u mm R m mm 3 L 2 mm mm mm g \Q N Mk kk U bk QQ INVENTORS Morgan C. Sze William V. Bauer ATTORNEYS United States Patent 3,429,804 TWO-STAGE HYDROTREATING 0F DRIPOLENE Morgan C. Sze, Garden City, and William V. Bauer, New York, N.Y. (both The Lummus Company, 385 Madison Ave., New York, N .Y. 10017) Filed May 25, 1965, Ser. No. 458,540 U.S. Cl. 208144 Int. Cl. C07c 3/42, /16
7 Claims ABSTRACT OF THE DISCLOSURE This invention relates to the production of benzene, toluene and xylene from dripolene or pyrolysis gasoline, and more particularly, to the production of benzene, toluene and xylenes by the selective hydrogenation of diolefins, olefins and styrenes contained in the byproduct dripolene or pyrolysis gasolines obtained from the production of olefins by the pyrolysis of hydrocarbons.
During the production of olefins by the pyrolysis of hydrocarbons, such as ethane and propane, there is produced in addition to the desired olefins, a considerable quantity of a normally liquid mixture of hydrocarbons commonly termed dripolene that contains almost all classes of hydrocarbons, but predominantly olefinic and aromatic hydrocarbons. Diolefins present are butadiene, isoprene, cyclopentadiene and its dimer, etc., While residual amounts of olefins are found, such as pentene, hexene, heptene, styrene, etc. Additionally, large quantities of aromatic compounds, such as benzene, toluene, ethylbenzene and xylenes are contained in dripolene, which are of value if recovered in high purity.
Similarly, the pyrolysis of virgin light, heavy or full boiling range naphtha or even heavier distillate stocks for ethylene and propylene production yields a hydrocarbon mixture in the normal gasoline boiling range which has a composition similar to dripolene. Such a mixture is known as pyrolysis gasoline.
Generally for the production of aromatic compounds, such as benzene, toluene and xylenes, from dripolene or pyrolysis gasoline the following sequence of steps are performed:
(1) First-stage hydrotreating of the pyrolysis gasoline to saturate the diolefins and styrenes while minimizing the hydrogenation of olefins;
(2) Fractionation of the hydrotreated product into three fractions, one fraction constituting -a pre-benzene cut boiling below 150 F., a second fraction containing C to C hydrocarbons boiling between about 150 to about 300 F., and a third fraction constituting a postxylene cut boiling from about 300 to 400 F.;
(3) Second-stage hydrotreating of the C to C fraction to saturate the olefins and to remove essentially all sulfur; and
(4) Extraction of the hydrotreated C to C fraction to produce benzene, toluene and xylenes.
As mentioned in copending application Ser. No. 376,358, filed June 19, 1964, now abandoned, in order to use pyrolysis gasolines in gasoline blending, it is neces- 3,429,804 Patented Feb. 25, 1969 sary to eliminate substantially all of the diolefins and styrenes, and this can be accomplished by hydrogenating the styrenes to the corresponding aromatics, and the conjugated diolefins to the corresponding monoolefins. In fact, for gasoline blending purposes, it is not desirable to hydrogenate the diolefins completely to form saturated hydrocarbons, since saturated hydrocarbons of the paraflin type usually have lower octane ratings than the corresponding monoolefins.
Significant quantities of dicyclopentadiene are contained in dripolene obtained by the pyrolysis of a very light hydrocarbon, such as ethane or propane. In the hydrotreating of such a feed stock, it has been found that dicyclopentadiene behaves as an olefin and consequently, is not completely hydrotreated in the first stage. During fractionation of the hydrotreated product, some of the dicyclopentadiene splits to cyclopentadicne under the infiuence of heat at the higher temperature, and is subsequently withdrawn from the fractionation zone in the C to C fraction. Second stage hydrotreating of the C to C fraction in the normal manner, i.e., mixing the same with hydrogen at ambient temperature and the subsequent preheating of the mixture has resulted in polymer or coke deposition in the preheater tubes and the second stage hydrotreating reactor. Such depositions shorten the on-stream factor and may render the unit inoperable.
It is an object of the invention to provide an improved process and reactor system for hydrogenating diolefins and styrenes contained in a dripolene, pyrolysis gasoline, and the like.
Another object of the invention is to provide an improved process and reactor system for purifying hydrocarbon streams boiling in the methyl naphthalene range (approximately 360 to 500 F.) for recovery of aromatics such as benzene, toluene and naphthalenes, after hydrodealkylation.
Still another object of the invention is to provide an improved process for producing benzene, toluene and xylenes from dripolene or a pyrolysis gasoline which substantially eliminates polymer and coke deposition during second stage hydrotreating of a C to C fraction separated from the product of first stage hydrotreating of the pyrolysis gasoline.
Yet another object of the invention is to provide an improved process for selectively hydrogenating the diolefins and styrenes present in dripolene or a pyrolysis gasoline.
Still another object of the invention is to provide a hydrogenation reactor system such that the reaction temperature can be controlled within narrow limits at the optimum range for selective hydrogenation of the diolefins and styrenes contained in pyrolysis gasoline obtained by the pyrolysis of hydrocarbons.
Further objects and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawing which is a schematic flow diagram of the invention.
In accordance with our invention, dripolene or a pyrolysis gasoline, obtained from a plant preparing olefins by the pyrolysis of a hydrocarbon or hydrocarbon mixture is introduced into a first stage hydrotreating zone where the feed stock is hydrotreated in the liquid phase with a noble metal catalyst to selectively hydrogenate the diolefins and styrenes contained in the feed. The first stage reactor is operated at a temperature and pressure of about to about 400 F., and of from 200 to 1000 p.s.i.g., respectively, depending upon the feed stock, its sulfur content and the hydrogen gas purity (i.e., hydrogen content). Fresh feed to the reactor is mixed with recycled hydrotreated gasoline directly from the bottom of the reactor which has already been stabilized and is introduced into the top of the reactor and passed cocurrently with hydrogen in the presence of the noble metal catalyst. In this manner, the fresh feed is brought to reaction temperature without passing through any tubular preheating exchanger. At least, indirect preheat above 175 F., at which the tendency to polymerize is essentially nil, is not required. The net reactor efflueut comprising -a vapor-liquid mixture is cooled and the stabilized product separated from the uncondensed gases. The noble metal catalysts that can be used include platinum and palladium on a suitable support.
The hydrogenation of diolefins is highly exothermic, and depending on the quantity of diolefins and styrenes contained in the feed, the temperature rise between the inlet and outlet of the reactor may be as much as 200 to 400 F. Since it is desirable to operate at as nearly isothermal conditions as possible in order to obtain high selectivity and minimize catalyst deposits, isothermal conditions are approached by recycling a portion of the liquid efiluent from the reactor. Such recycled portion is not cooled prior to admixing the same with the feed, as distinguished from known processes. By maintaining a recycle ratio of from 1:1 to 1, reactor efliuent to reactor fresh feed, it is possible to reduce the temperature rise within the reactor to 100 F., or less. With lower diolefins content and feed stocks requiring less hydrogen absorption, the heat liberated is less, and lower recycle ratios may be used to give the desired temperature control. Thus, the pyrolysis gasoline may be easily hydrotreated in the liquid phase with high selectivity at the preferred temperature range and with the elimination of any need for a tubular surface. Additionally, the reactor system is readily adaptable to periodic regeneration of the catalyst in situ since there is no requirement of a tubular surface. Also, because of the excellent temperature control, it has been found that small increments in temperature rise can be easily regulated to compensate for increased sulfur content of the feed stock. For example, when the reactor is shifted from a feed containing 40 ppm. sulfur to one containing 330 p.p.m., an increase in operating temperature of about 50 F. compensates for the deactivating effect of sulfur on the catalyst. In fact, hydrogenation of the diolefins and styrenes appear to be more selective. It is actually advantageous at times to add some sulfur purposely to a low sulfur feed and operate at a higher temperature in order to obtain better selectivity.
One additional surprising result is that at the recycle ratios considered, there is no need to increase the amount of catalyst required. In other words, it is surprising to find that the only important space velocity is the space velocity based on the fresh feed; the dilution effect or presence of recycle appears to have no significant effect on the extent and/ or selectivity of the hydrogenation.
The product from the first stage hydrotreating zone is passed tnrough a fractionation zone wherein such product is separated into (a) a prebenzene fraction boiling below about 150 F., (b) a C to C fraction boiling between about 150 to about 300 F., and (c) a postxylene fraction boiling above 300 F.
A hydrogen-containing gaseous stream is preheated to a temperature of about 400 to about 650 F. and subsequently heated in a furnace to a temperature of about 1000 to about 1200 F. The C -C fraction is preheated to a temperature below about 420 F., and preferably below 375 F., is introduced into the coil of the furnace and intimately admixed with the hydrogen stream to rapidly vaporize the C -C fraction. The quantity and temperature of the hydrogen containing gaseous stream admixed with the C -C fraction may be varied but must effect the rapid vaporization of the feed (i.e., so that the resulting gas mixture is above its dew point) or at least so much of the feed as contains any polymerizable components. Generally about 6,000 to 14,000 standard cubic feet of a hydrogen containing gaseous stream is admixed hydrogen containing gaseous stream is a recycle stream obtained from downstream processing equipment. Only small quantities of make-up hydrogen need be added, since hydrogen consumption is nominal for the hydrotreating of the C -C fraction. An additional benefit of lowered energy requirements is derived from using such a recycled hydrogen stream, since the stream is recovered at the system pressure, and only the pressure drop through the system must be overcome. The resulting mixture, at a temperature of between about 625 to about 800 F., preferably 650 to 750 F. is withdrawn from the furnace and introduced into a second stage hydrotreating reactor which contains a cobalt and molybdenum oxide catalyst on a suitable support. Rapid vaporization of the C to C fraction substantially eliminates polymer and coke deposition in the tubes of the preheater and in the second stage hydrotreating zone.
The efiiuent from the second stage hydrotreating zone, after treatment to remove lighter components such as hydrogen and C and lighter hydrocarbons, is introduced into an aromatic separation zone wherein such product is treated in a conventional manner, such as by liquidliquid extraction, azeotropic distillation, or adsorption forming a product comprising nitration grade benzene, toluene and xylenes.
Referring to the drawing, a pyrolysis gasoline in line 10 obtained from the recovery unit of a plant (not shown) for the pyrolysis of hydrocarbons, is mixed with recycle reactor effluent in line 11, as more fully hereinafter described, and introduced through line 12 into reactor, generally indicated at 13.
The reactor 13 includes a vapor-liquid distributor plate 14 and catalyst zone, generally indicated as 15. The catalyst zone is filled with a noble metal catalyst, such as platinum or palladium on a suitable support. Hydrogen, or a mixture of hydrogen and light hydrocarbons such as methane, is admitted through line 16 and is introduced through line 18 into reactor 13, and the hydrogen stream and the liquid feed in line 12 are passed cocurrently through reactor 13. A temperature of between 120 to about 400 F. is maintained in reactor 13, preferably 150 to 370 F., and a pressure of from 200 to 1000 p.s.i.g. is maintained on reactor 13, preferably 400 to 900 p.s.i.g.
As hereinbefore described, the preferred reactor temperature range depends upon the feed stock and its sulfur content. Higher sulfur requires higher operating temperatures. A feed containing more cyclohexadiene requires higher hydrogenation temperature than one containing isoprene or cyclopentadiene. The required reactor pressure depends upon hydrogen purity and reactor temperature. Lower hydrogen purity requires higher total pressure to provide the desired hydrogen partial pressure. In order to keep at least 75% of the feed in the liquid phase, higher pressure is needed at higher temperatures.
A portion of the liquid effluent from the reactor 13 is withdrawn through line 19 by pump 20 and constitutes the liquid recycle reactor efiiuent in line 11. The recycle ratio of reactor efiiueut to fresh feed may be from 1:1 to 10:1, preferably from 2:1 to 5:1. In this manner, isothermal conditions within the reactor may be more closely approached with a temperature rise of 100 F. or less during passage of the feed in line 12 through the reactor 13. Net reactor effiuent consisting of vapor and liquid is withdrawn from reactor 13 through line 21 to heat exchanger 23 wherein the efiiuent is cooled to near ambient temperatures of from to F. so as to condense substantially all of the hydrocarbons boiling above methane.
The now cooled efiluent is withdrawn from heat exchanger 23 through line 24 and is passed to separator 25. An overhead gaseous stream including methane and unreacted hydrogen is withdrawn from separator 25 and vented through line 26. Should a low partial pressure of hydrogen be desired, a portion of the gaseous stream in line 26 may be recycled through line 27 under the control of valve 28 to line 18. Generally, the concentration of unreacted hydrogen is insuflicient to justify recycle of any portion of the gaseous stream in line 26 so as to maintain the concentration of methane below about 50% in reactor 13. A stabilized product is withdrawn from separator through line 29.
Depending on the feed stock, the hydrogen absorption and therefore heat of reaction, it may be necessary to include a cooler 30 in line 11, and/ or a fresh feed preheater 31 in line 21 to provide for flexibility of operation. Should the feed stock have a high hydrogen absorption, the recycle stream should be passed through cooler 30 prior to admixing the same with the feed stick. Conversely, should the hydrogen absorption of the feed stock be too low, it may be necessary to preheat the feed stock by passages through line 32 under the control of valve 33 to preheater 31, and thence into line 12. It is apparent from the foregoing that the cooler 30 and preheater 31 are not used at the same time, and are operated when the feed stock has a high or low hydrogen absorption, respectively.
The stabilized product in line 29 is passed to a fractionation zone comprised of fractionation towers 35 and 36. Fractionation tower 35 includes reflux condenser 37, and reboiler 38; and fractionation tower 36 includes reflux condenser 39 and reboiler 40. In fractionation tower 35 the stabilized product in line 29 is fractionated into an overhead containing C and lighter hydrocarbons which are withdrawn as overhead in line 41 and passed to condenser 37. After satisfying the reflux requirements of the fractionation tower 35, the net overhead is withdrawn through line 42. The C and heavier hydrocarbons are withdrawn as bottoms through line 43. A portion of the bottoms are passed through line 44, reboiler 38, and thence through line 45 to fractionation tower 35 to provide the reboil requirements for fractionation tower 35. The net bottoms in line 46 are introduced into fractionation tower 36 and separated into a C to C aromatic fraction and a residual gasoline fraction.
The C to C aromatic fraction is withdrawn as overhead from fractionation tower 36 through line 47 and passed to reflux condenser 39. A portion of the liquid stream withdrawn from condenser 39 is passed through line 48 to provide the reflux requirements for fractionation tower 36. The net overhead from tower 36 is withdrawn through line 49 and passed to subsequent processing units as more clearly hereinafter described. The bottoms of fractionation tower 36 withdrawn through line 50, with a portion thereof being passed through line 51, reboiler 40, and reintroduced into fractionation tower 36 through line 52. The net bottoms constituting a residual gasoline fraction are withdrawn from fractionation tower 36 through line 53 and passed to storage and blending units (not shown).
The C -C aromatic fraction in line 49 is passed to heat exchanger 54 wherein such fraction is passed in heat exchange relationship with the effluent from the second stage hydrotreating reactor as is more fully hereinafter described. In heat exchanger 54, the aromatic fraction is heated to a temperature of less than about 420 F., preferably about 375 F. A hydrogen-containing gaseous stream in line 56, together with make-up hydrogen in line 57 are combined and passed through line 58 to compressor 59 driven by suitable drive means 60. In compressor 59, the hydrogen-containing gaseous stream is compressed to a pressure of about 750 to 800 p.s.i.g. The now compressed hydrogen-containing gaseous stream is passed from compressor 59 through line 61 to heat exchanger 62 wherein the stream is heated to a temperature of about 400 to about 650 F. and is thereafter passed through line 63 to heater 64 wherein the hydrogen-containing gaseous stream is further heated in furnace coil 65 to a temperature of about 1000 to about 1200 F. At this point, the aromatic fraction in line 55 is injected into the hydrogen-containing gaseous stream and mixed within the furnace coil 65 whereby the temperature of the combined stream is raised to about 575 to about 650 F., with substantially instantaneous vaporization of the aromatic fraction. Practically, injection generally takes place outside the furnace and the mixture returns immediately to the furnace. The resulting vapor mixture is additionally heated in the final portion of the furnace coil 65 and withdrawn from the furnace 64 through line 66 at a temperature of about 650 to about 750 F.
As noted hereinabove, it is essential that vaporization be substantially instantaneous, but whether or not vaporization must be complete depends on the composition of the aromatic fraction in line 55. In other words, as long as all of the polymerizable components are quickly vaporized, trouble will be avoided. As one skilled in the art will recognize, the volume of hydrogen-containing gas required in the system will be less if complete vaporization is not required, and less volume of recycle gas means lower energy requirements for compressor 59 and heater 64. Determination of the required vaporization must be made, therefore, for the particular liquid being treated for most economic operation.
It has been found that where vaporization is less than total, the injection of the aromatic fraction as described above is satisfactory. Where total vaporization is required and the mixture of vaporized aromatic fraction and hydrogen has a dew point about equal to the desired second stage reactor inlet temperature, it is better to pass the gas all the way through heater 64 and into line 66 prior to injection. In this instance, the aromatic fraction is introduced directly into line 66 via line 55.
The efiluent in line 66 is passed to a second stage hydrotreating reactor 67 including catalyst reactor bed 68 comprised of a conventional hydrogenation catalyst, such as a cobalt and molybdenum oxide on a suitable support. During passage through reactor 67, any cyclopentadiene or dicyclopentadiene present is hydrogenated to cyclopentane or pentanes. Reactor 67 is maintained at a temperature within the range of about 625 to 800 F., preferably 650 to 700 F. The reactor efiluent in line 69 is passed through heat exchangers 62, 71, 54 and 72, consecutively. In heat exchanger 62, the reactor efiiuent is passed in heat exchanger relationship with the hydrogencontaining stream to preheat such stream to a temperature of from 400 to about 650 F. The reactor eflluent in line 69 also provides the heat necessary in heat exchanger 71 to provide the reflux requirements for a stripping column as more clearly hereinafter described. In heat exchanger 54, the reactor effluent preheats the C to C fraction in line 49 withdrawn from fractionating tower 36 prior to introduction into the furnace 64. The reactor elfiuent is further cooled in heat exchanger 72 and introduced into separator 73 wherein hydrogen and methane are separated from the reactor efiiuent and withdrawn through line 56, which, together with required make-up hydrogen from line 57, constitutes the hydrogen-containing gaseous stream admixed in heater coil 65 with the C to C fraction in line 55.
The bottoms from separator 73 is withdrawn through line 74 and introduced into stripping column 76. An overhead fraction containing C and lighter hydrocarbons is withdrawn through line 77 and passed through condenser 78 and subsequently passed into surge drum 79. The lighter hydrocarbons, such as hydrogen and methane, are withdrawn from surge drum 79 through line 80, while the heavier hydrocarbons are withdrawn through line 81. A portion of the liquid stream in line 81 is passed through line 82 to provide the reflux requirements for stripping column 76, while the remaining portion is withdrawn and passed through line 83 to subsequent units (not shown).
The bottoms from stripping column 76, primarily C to C aromatic hydrocarbons, predominantly benzene, toluene and xylene are withdrawn through line 85 with a portion being passed through line 86 and heat exchanger 71 to provide the reboil requirements for stripping column 76. The remaining portion of the bottoms in line 85 is passed through line 87 and heat exchanger 88 and is introduced into an aromatics extraction zone, generally indicated as 89.
As hereinbefore mentioned, in aromatic extraction zone 89, the aromatic components of the C to C fraction are treated for example by liquid-liquid extraction, :azeotropic distillation, or adsorption to separate and produce an aromatic product containing nitration grade benzene, toluene and xylenes, which is withdrawn from the extraction zone through line 90. The other components contained within the C to C fraction are withdrawn from the aromatic extraction zone through line 91 and passed to subsequent processing units (not shown) for treatment as dictated by the composition of such products. In some instances it may be desirable to also pass such product to the blending and storage units for subsequent inclusion in various gasolines.
EXAMPLE Table A Boiling range, F 124-377 Octane No. (research method, clear) 100+ Bromine No. 65 Diene value 1 46 Sulfur, p.p.m. 80 Existent gum, mg./100 cc. 47 Induction period, min. 120
1 Calculated from component analysis.
A gaseous stream in line 18, at a temperature of 150 F. and comprising 11.12 s.c.if. per hour of 65 vol. percent hydrogen and 35 vol. percent methane, was introduced into the reactor 13. The outlet temperature of the reactor was 320 F. and the outlet pressure was 880 p.s.i.g. The net reactor effluent consisting of hydrotreated feed plus unreacted hydrogen was withdrawn through line 21 and subsequently cooled to a final temperature of 100 F. during passage through heat exchanger 23. Approximately 70% of the hydrogen was found to have combined with the feed stock.
The thus cooled reactor effluent was introduced into separator 25 from which an overhead gaseous stream containing hydrogen and methane was withdrawn. A stabilized product having the composition set forth in Table The hydrotreated stream in line 29 was introduced into fractionation tower 35 wherein a /0 separation was elfected with 0.33 lb. per hour of the C and lighter hydrocarbons being withdrawn as fractionation tower overhead in line 41 and 2.91 lb. per hour of the C and heavier hydrocarbons being withdrawn as net tower bottoms in line 46.
The C and heavier hydrocarbon fraction in line 46 was passed to fractionation tower 36 wherein a C /C separation was effected. 2.31 lb. per hour of a C to C fraction boiling in the range of 150 to 300 F. was withdrawn as net tower overhead in line 49 and had a composition set forth in Table C.
I he C to C hydrocarbon fraction in line 49 at a temperature of F. was preheated in heat exchanger 54 to a temperature of 375 F. Ninety and six-tenths (90.6) set. per hour of a hydrogen-containing gaseous stream (60% hydrogen, 40% methane) and 5.83 s.c.f. per hour of a makeup hydrogen-containing gas (67% hydrogen, 33% methane) was compressed in compressor 59 to a pressure of 675 p.s.i.g., and passed through heat exchanger 62 wherein the compressed hydrogen-containing gaseous stream was preheated to a temperature of 650 F. The preheated hydrogen-containing gaseous stream was then introduced into the coil 65 of the furnace 64 and, heated to a temperature of 1000 F. At this point the preheated C to C hydrocarbon fraction was injected into the hydrogen-containing gaseous stream in furnace 64 resulting in the rapid vaporization of the C to C fraction. The effluent from the furnace 64 at a temperature of 710 F. was passed through line 66 into reactor 67 containing a catalyst consisting of cobalt and molybdenum oxides supported on alumina. Over an extended period of time, there was no indication of pressure buildup nor any effect on catalyst activity.
The reactor efiluent at a temperature of 750 F. and a pressure of 670 p.s.i.g. in line 69 was passed serially through heat exchanger 62, 71, 54 and 72 wherein the reactor effluent was cooled to a temperature of F. The now cooled reactor eflluent was introduced into separator 73 wherein 2.31 lb. per hour of a liquid hydrocarbon fraction was withdrawn through line 74 and had following properties as set forth in Table D.
Table D Color Water white Bromine No 0.9 Thiophene, p.p.m. 1
Table E Boiling range, F -300 Bromine No. 1 Thiophene, p.p.m. 1
The C to C fraction was contacted with diethylene glycol solvent. The raflinate is taken out at line 91 and the extract after separation from the solvent is removed through line 90 as a pure aromatic stream containing essentially only benzene, toluene and xylenes. 'I'his stream may be contacted with clay to improve its acid color property and then fractionated to yield high purity nitra tion grade products.
The aromatic products from the separation zone 89 met nitration grade specifications.
Although the present invention has been described and illustrated with reference to specific examples, it is understood that modifications and variations may be made by those skilled in the art within the principles and scope of the invention as expressed in the appended claims. Moreover, those skilled in the art will recognize that while the invention has been described with particular reference to the treatment of dripolene and pyrolysis gasolines, the
second-stage hydrotreating has much broader application. In particular, it may be employed generally for sulfur and olefin removal from hydrocarbon streams boiling in the range of methyl naphthalenes (about 360 to 500 F.).
What is claimed is:
1. A process for hydrotreating dripolene, containing aromatic hydrocarbons and unsaturated components, including, monoolefins, diolefins and styrenes, to recover the aromatic compounds essentially free of the unsaturated components and with the essential elimination of coke and gum formation which comprises:
(a) mixing heated hydrotreated product with dripolene to directly heat said dripolene to a first hydrotreating reaction zone inlet temperature;
(b) introducing said heated fraction, containing hydrotreated product, and a first gaseous stream containing hydrogen into the first hydrotreating reaction zone containing a noble metal catalyst, said reaction zone being maintained at a temperature between about 120 F. and about 400 F.;
(c) withdrawing a hot first hydrotreated product, essentially free of the diolefins and styrenes of the dripolene and containing the other aromatic hydrocarbons and mono-olefins, from said zone, said hot first hydrotreated product being at a temperature greater than the temperature of the dripolene mixed in p (d) passing a portion of said hot first hydrotreated product to step (a) as the heated hydrotreated product to heat said dripolene;
(e) fractionating the remaining portion of said first hydrotreated product to form a hydrocarbon traction containing predominantly C to C aromatic hydrocarbons and unsaturated components;
(f) injecting said hydrocarbon fraction at a temperature less than about 420 F. into a second gaseous stream containing hydrogen, the temperature and quantity of said second gaseous stream and rate of injection being at a value such that at least the unsaturated components of said hydrocarbon fraction are substantially instantaneously vaporized;
(g) passing the gaseous mixture of step (-f) through a second hydrotreating reaction zone containing a hy- 10 drotreating catalyst and maintained at a temperature between about 625 F. and about 800 1 and (h) recovering a second hydrotreated product from said second reaction zone, containing the C -C aromatic hydrocarbons of the dripolene andessentially free of unsaturated components.
2. The process as defined in claim 1 wherein in step (f) the hydrocarbon fraction is substantially instantaneously heated to above the dew point thereof.
3. The process as defined in claim 2 wherein the hydrocarbon fraction is heated in step f) to a temperature between about 575 F. and about 650 F.
4. The process as defined in claim 3 wherein the second gaseous stream is at a temperature between about 1000 F. and about 1200" F.
5. The process as defined in claim 4 wherein about 6000 to about 14,000 s.c.f. of said second gaseous stream containing from about to about mol percent hydrogen is admixed with one barrel of said hydocarbon fraction.
6. The process as defined in claim 3 wherein the first reaction zone is maintained at a pressure of from about 200 to about 1000 p.s.i.g., the dripolene in step (a) prior to mixing is at a temperature below about F. and the heated hydrotreated product is employed in step (a) in an amount between about 1:1 and about 10:1 based on the dripolene.
7. The process as defined in claim 1 wherein the hydrocarbon fraction in step (f) is heated to the second hydrotreating reaction zone temperature.
References Cited UNITED STATES PATENTS 3,094,481 6/1963 Butler et al 20=8-89 3,221,078 11/1965 Keith et al. 208144 FOREIGN PATENTS 624,424 7/ 1961 Canada.
DELBERT E. GAINTZ, Primary Examiner.
C. E. SPRESSER, JR., Assistant Examiner.
US. Cl. X.-R.
|Cited Patent
|Filing date
|Publication date
|Sep 9, 1960
|Jun 18, 1963
|Exxon Research Engineering Co
|Hydrofining process with temperature control
|Jul 6, 1961
|Nov 30, 1965
|Engelhard Ind Inc
|Selective hydrogenation of olefins in dripolene
|Jul 25, 1961
|Universal Oil Prod Co
|Process for refining coke-forming hydrocarbon distillates
|Citing Patent
|Filing date
|Publication date
|Nov 16, 1966
|Dec 16, 1969
|Velsicol Chemical Corp
|Solvent extraction of dripolene fractions to yield polymerizable aromatic monomer mixtures and solid resin products therefrom
|Jun 13, 1968
|Mar 3, 1970
|Air Prod & Chem
|Pyrolysis gasoline hydrogenation
|Apr 28, 1969
|Nov 3, 1970
|Universal Oil Prod Co
|Method for hydrogenation
|Jan 30, 1968
|Nov 10, 1970
|Standard Oil Co
|Start-up method for a low-temperature hydrogenation process
|Jun 10, 1970
|Jun 13, 1972
|Monsanto Co
|Hydrogenation process
|Feb 21, 1975
|Jul 13, 1976
|Universal Oil Products Company
|Hydrogenation and hydrodesulfurization of hydrocarbon distillate with a catalytic composite
|Sep 23, 1974
|Nov 16, 1976
|Universal Oil Products Company
|Process for the conversion of hydrocarbonaceous black oil
|Aug 6, 1975
|Dec 21, 1976
|Mobil Oil Corporation
|Method for producing gasoline from methanol
|Oct 19, 1977
|Sep 12, 1978
|The Lummus Company
|Two-stage hydrotreating of pyrolysis gasoline to remove mercaptan sulfur and dienes
|Aug 29, 1995
|Jun 16, 1998
|Krupp Koppers Gmbh
|Process and apparatus for producing aromatic hydrocarbon composition
|May 19, 1992
|Dec 8, 1998
|Mobil Oil Corporation
|Process for rejuvenating used alkanolamaine solutions
|Sep 23, 1974
|Feb 17, 1976
|Title not available
|Aug 4, 1992
|Feb 16, 1994
|NEUMANN + STALLHERM GmbH
|Process for upgrading crude benzene
|U.S. Classification
|208/144, 208/211, 208/95, 585/266, 585/271, 208/89, 585/485, 208/210
|International Classification
|Cooperative Classification
|European Classification


text:
I really liked this. I can't wait to try variations on it. I didn't use any croutons to cut down on unnecessary carbs, but me and my carnivorous unhealthy food-loving fiance ate this up. I doubled the recipe because I had to use the chicken I had, and took extra soup into the office and everyone loved it. Will definitely make again. What a healthy alternative to your everyday chicken noodle!
Chicken & Spinach Soup with Fresh Pesto
From EatingWell: September/October 2009
This fragrant, Italian-flavored soup takes advantage of quick-cooking ingredients—boneless, skinless chicken breast, bagged baby spinach and canned beans. It features a simple homemade basil pesto swirled in at the end to add a fresh herb flavor. If you are very pressed for time, you can substitute 3 to 4 tablespoons of a store-bought basil pesto.
65 Reviews for Chicken & Spinach Soup with Fresh Pesto
Great soup - I make a whole batch of this on Sunday nights and have soup for the entire work week. I did not chop my spinach and added 9oz instead of 6oz. I put in about 4 tbl of pesto but I think now I'll use more like 3. The storebought pesto can be very overpowering. Love this soup!
DELICIOUS!!!!! After reading the comments I will try artichokes next time...I will DEFINATELY make this dish again it was so hearty and tasty! I opted to make the pesto myself and have to say it was wonderful and extremely simple. Love this soup I give it 5 stars.
This soup smelled so good after I poured it in the bowl, that I burned my tongue trying to hurry up and taste it. It was so easy to make! I used some artichoke hearts out of the can as I saw someone else do that and I used store bought pesto. So as it cooled down and I actually got to taste it, it is very good and healthy, the flavors come together very nice and gives you that warm and fuzzy feeling. I will definitely make again!!

subset: commoncrawl


text:
FBI Agents Encouraged to Search Your Trash, Public Databases Just to Sniff Around For Crime
What the hell happened to America after 9/11? Have we lost sight of our founding principles?
The FBI plans to issue new rules for its agents saying, essentially, that they can and should dig through our trash and search databases (Facebook, Twitter?) if people who aren't suspects but who are simply being assessed or looked at.
Scary? The news comes after ...
... a scathing report in the New Yorker about the government's failed case against U.S. intelligence worker and whistleblower Thomas Drake, in which former National Security Agency mathematician Bill Binney claims, according to the story ...
... that the agency now stores copies of all e-mails transmitted in America, in case the government wants to retrieve the details later. In the past few years, the N.S.A. has built enormous electronic-storage facilities in Texas and Utah. Binney says that an N.S.A. e-mail database can be searched with "dictionary selection," in the manner of Google.
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The feds are in your trash, your email, and phone conversations, apparently.
The new FBI trash-digging policy will be a part of the agency's updated Domestic Investigations and Operations Guide, a source tells the New York Times.
The changes apply not to criminal investigations but, apparently, to agents' ability simply to sniff around "proactively," according to the Times.
The paper states that some agents wanted the trash-sifting powers so they could use evidence found among refuse to pressure people to snitch on others.
(Great. So you might not even be the target of a federal probe or even suspected of a federal crime, but agents will use your discarded mattress tag to get you to flip on your neighborhood pot dealer).
The ACLU isn't happy, with Michael German, a former FBI agent turned ACLU lawyer, telling the paper:
Claiming additional authorities to investigate people only further raises the potential for abuse.
So watch your trash, people. Or ... put some real vile stuff in there. Like Anthony Weiner photos.
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IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards,
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Nowadays authentication in Wireless Mesh Networks (WMN) refers to the 802.1X authentication methods or a Preshared key authentication, and makes use of certifcates or shared secrets. In wireless environments, the management of certifcates is a cumbersome task as certifcates require deploying a Public Key Infrastructure (PKI) and Certifcation Authorities (CA). They also require defning a certifcate management policy to control the generation, transmission and revocation of certifcates. During the last decade, ID-Based Cryptography (IBC) appeared as a good alternative to PKI. IBC proposes to derive the public key from the node's identity directly thanks to the use of a Private Key Generator (PKG). In this article, we present an authentication method relying on an ID-Based signature and encryption schemes that use the Sakai-Kasahara key construction. The resulted authentication scheme is suitable to IEEE 802.11s mesh networks and resistant to the key escrow attack.
A not-for-profit organization, IEEE is the world's largest technical professional organization dedicated to advancing technology for the benefit of humanity.© Copyright 2016 IEEE - All rights reserved. Use of this web site signifies your agreement to the terms and conditions.


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Bard's One Hundred and Forty-Ninth Commencement tooks place on Saturday, May 21, 2009. Bard President Leon Botstein conferred 405 undergraduate degrees on the Class of 2009 and 128 graduate degrees.…+ More details
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Tag: Cell Phones - Page 13
CES 2009: Powermat Sports Green Charging, Or Does It?
Powermat has an exclusive looking booth at CES. I got an appointment to go in and see what their technology has in store for charging gadgets. The basic rundown of Powermat is: You have a single mat that plugs into the wall.
CES 2009: LG and GotWind's Mobile Phone Charging Station (Video)
LG partnered with GotWind and has erected a solar/wind cell phone charging station. We're well familiar with GotWind around here, and it's great to see them head to the states to help LG create the first renewable energy
CES 2009: Solar and Wind Hybrid Charger from Kinesis Industries (Video)
Kinesis has created a solar/wind hybrid charger - the K2 - for use with USB devices such as cell phones. It's literature touts the ability to recharge a cell phone 5 times on one full K2 battery.
CES 2009: Visiting the Motorola Renew Mobile Phone
In the spirit of second chances, I stopped by Motorola's booth to check out the Renew mobile phone and see if it might be worth a few kinder words than I gave it before. But, turns out it's a greenwashed phone that, I'm
CES 2009: Motorola Launches The First Carbon Neutral Cell Phone
Photos via Motorola CES kicks off tomorrow and we'll be there to give you the eco-scoop. But there's so much happening, we can't wait to get started. So, here's news about the world's first "carbon neutral" mobile phone, the Renew, courtesy of Motorola.
5 Features That Would Make Smart Phones Really Smart
Photo via Chris Jordan
New E-Waste Problem: People Want to be Buried with their Cell Phones
How this slips past the EPA, gee, we'll never know.
Gas Cubby A Great Last Minute Green Gift
Gas Cubby is a super cool iPhone app that helps users monitor their driving habits and get a little greener.
Pedal-Per-Minute With Bike-Powered Cell Phone Charger
OK, so this isn't break-through technology. But it does show the increasing availability of convenient alternative energy for charging gadgets.
Mass Customization: Design Your Table on Your Cell Phone
TreeHugger readers don't appear to share my fascination with mass customization, the idea that you can order exactly what YOU want, made to your specifications, instead of having to take what Mr. Big Box offers. One recent extreme example was
Grass Concept Phone: Pass or Fail?
When I first saw this grass phone concept pop up on Yanko Design's website, I did a half-scoff, a "yeah, sure," and clicked the red X on the page tab.
Energy-Saving Charger Rescues Phones from Vampire Power
A new energy efficient charger claims to be the first "green" cell phone charger to hit the UK, and also says it has what it takes to end wasted power during cell phone charging. O2 has launched a universal cell phone charger that claims
Using Sound Waves to Charge Cell Phones
We've seen ways to charge cell phones by fuel cells, sunlight, wind and even dancing. But what about with sound waves?
Nokia Entering Smart Home Scene with Mobile Phone Project
The iPhone isn't the only cell phone that will allow you to adjust your home's power consumption. Nokia has entered the smart home scene and is working on providing a new option for controlling your smart home via your mobile phone.
UbiGreen: Not Just Another Carbon Footprint Phone App (Honest!)
You gotta love it when your phone does work for you. Especially when that work it keeping your carbon footprint in check.
Fuel Cell Stickers for Charging Gadgets
Slap a sticker on your cell phone and consider it charged. Well, that's the goal of myFC, anyway.
Cell Phone Industry Looks to Chargers for Reputation Repair
It's quickly becoming common knowledge that the efficiency of a charger plays a big role in the energy consumption of a device. Energy Star makes this very clear, and so does Motorola's history in making efficient chargers for cell
Yellowstone Proposes Expanding Cell Phone Coverage: Readers, Should National Parks Be Cell Phone Free Zones?
OK TreeHugger readers, confession time. How many of you bring your cellphone with you when you go hiking, or whatever you do when you want to get out into nature? I confess that I do it—if only because it was


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Patrick Industries (PATK): Q2 EPS of $0.7 beats by $0.09. Revenue of $159.6M. (PR)
ETF Hub
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DEFINITION of 'Carte Blanche'
Carte blanche is a French term that means "blank document." Carte blanche is commonly used in English to refer to a check that has been signed but does not have a dollar amount written in. The recipient of such a check then writes in whatever dollar amount he wants or needs.
BREAKING DOWN 'Carte Blanche'
The term "carte blanche" is more commonly used figuratively than literally. It usually means someone in power has given someone else the unconditional authority to spend money in a given situation or make decisions about that situation. This term is commonly used in politics and business. Carte blanche arrangements are often a bad idea because of their high potential for abuse.
Sometimes a person provides a blank check to a trusted agent, such as when making payment on a debt for which she does not know the amount. In the United States, the legal term for a blank check is "incomplete instrument." Blank checks are dealt with in the Uniform Commercial Code (UCC). The UCC does not make the issuance or acceptance of a blank check illegal. However, if a person accepting such an instrument enters an amount on the check that is unauthorized by the issuer, the UCC considers it an illegal alteration.
A counter check is sometimes referred to as a blank check. A counter check is a check that banks sometimes provide to customers who are making withdrawals or who have just opened an account and haven't had time to order pre-printed checks. Typically, these checks lack some of the information commonly printed on checks, and many businesses refuse to accept them due to their high incidence of abuse.
Carte Blanche in Politics and Economics
Sometimes "carte blanche" is used in politics, economics or law to refer to full powers, a term in international law referring to the granting of authority to a designated person or entity to take the actions or spend the money necessary to achieve a result.
For example, the U.S. Gulf of Tonkin Resolution gave President Lyndon B. Johnson full powers to "take all necessary measures" to prevent aggression by Vietnam against the United States and its allies. This resolution has been called a blank check and a carte blanche. These terms have also been widely used to describe the powers granted to U.S. President George W. Bush to "to use all necessary and appropriate force" to hunt down the people responsible for the 9/11 attacks in New York City and Washington, D.C.
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Skip to comments.Why the Leftist outrage at the acquittal of George Zimmerman?
Posted on 07/19/2013 3:01:36 AM PDT by marktwain
There is an illustrated list of Leftist and media reactions here.
"Its 2013 and an American jury just acquitted a man who admitted to stalking and killing an unarmed child" Richard Dreyfus, actor
I think you can see why in the face above. That face is expressing glee -- barely restrained delight. The slightest hint that America is unjust is manna from heaven for Leftists. They build their self-esteem on being wiser and more compassionate than "the masses". And given America's black/white tensions, a chance to see others as racist is not to be missed. It is America's most powerful form of condemnation so any chance to use it must be used even if it is only remotely justified.
It's pathetic that people need to condemn others in order to boost their own self-esteem but that's Leftists. They never cease finding fault.
I note however that many of the commentators refer to the 6' tall Martin as a "child". So the constant media use of pictures of Martin when he was a child may have misled some commentators in an important way. It would have made it less plausible that Zimmerman acted in self-defense.
Link to Gun Watch
He is an Australian academic who studied the psychology of the left.
So go ahead, Leftmedia, hold your breath until you turn blue. Please.
The jury has heard the evidence, the verdict is "not Guilty".
'nuff said.
The re-telling of Trayvon's ordeal and Zimmerman's trial is all dishonest. Not merely mendacious, but truly and intentionally dishonest by cherry picking this and that. The Dreyfus quote above is only a mild example.
And not widely asked, but how long would Zimmerman have lasted if he had not defended himself? How many more head-smashed would it have taken to put out his lights?
I think you can see why in the face above. That face is expressing glee — barely restrained delight. The slightest hint that America is unjust is manna from heaven for Leftists.
I agree, Sorry if I sound... Mystical isn't the right word... Perhaps credulous...What ever, I can't find the right word right now. But where I was going is that I occasionally think that these people are 'psychic vampires' they literally seem to feed off of misery and inflict more of it so that they have more 'food'.
So many of them I've known over my life seem to be the happiest when they have miserable people around them. Some generate that misery themselves, others just swarm to where it is occurring.
You can shroud it in psychological terms if you want to, but just step aside sometime and look with a uncritical eye, I think you'll see what I mean.
They are giving it so much attention to draw attention away from Benghazi, Egypt and Obama commie care. Think about it: Self-defensee cases go on every-single-day, yet this one gets all this attention? Yeah and while you are pay attention pay no attention to the putz who is empowering radical Islam in the middle east and has everything lined up to destroy the US economy because the 911 terrorists failed.
Speaking of Richard Dreyfus, is he still doing massive amounts of cocaine while declaring himself a genius?
"Ok.. Help me out. Treyvon got killed because he just outta nowhere decided to attack and try and kill Zimmerman Ice T, musician and actor"
I would like to address this. If everyone recalls, according to GZ, (if you believe his testimony, I do) TM turned around, walked back toward his vehicle with his hand in his waistband.
Folks, I have worked in a predominantly black, violent urban area for a long time and I KNOW this behavior. This is displayed by street thugs who are getting ready to rob or shoot you, or make you think that they are. Most the time it's a bluff, but you really can't take the chance. I have had it done myself, even as a uniformed police officer. It usually stops when the real guns come out, nevertheless, keep this in mind if you are approached in this fashion.
Don't get fixated by the accompanying verbal tirade either, this is done as a measure to mentally "stun" you while they close the gap. They don't use their sights, it's all point shooting or suckerpunching, so they have to get close.
The Left is outraged because they believe their own BS.
The Left is outraged because they want to own the streets.
My thoughts exactly.
It's impossible to unravel the web of lies and misdirection because you have lies built on wrong premises supported by fallacies.
One instance is the racial component of this event. I saw Zimmerman's mother on TV and noted she's even darker than me (well, in my "Winter coat", anyway). In what universe would George be considered "white" anything?
You don't have to be an idiot to be an actor, but it helps.
"If I mouth all of the politically-correct platitudes and make an ostentatious display of my superiority, perhaps the young lady to my left would let me remove her dress..."
One of the most valuable pieces of information posted on this entire affair. Streets smarts. The man who does not live his life fighting all of the time would not know this.
Its obvious Dreyfuss knows nothing about the case and is just saying what he thinks his comrades want to hear. Applies to all other knee-jerk liberals that have spouted offf recently too.
His best work was American Graffiti, playing a dipshit.
Well hell, if Richard (Dick) Doofus said it, it must be true. I think I'll join the Saint Trayvon bandwagon.
In a situation like that, don't let 'em get close.
There are learnable and usable tactics to stay far enough away from them, even as they are pressing.
Of course, if they press you, you may have to actually display or get ready to display.
"I don't want to have to shoot you, but I'm armed, and if you take another step toward me, I will consider it a deadly threat."
"Liberalism" is the political expression of Humanism,
which began with the lie
"you will be as gods [unto yourselves], knowing [and defining] good and evil [right and wrong] [for yourselves]"
Well that's certainly playing fair.
There are 5 Stages of a Violent Crime
Don't let 'em come close enough to ask for a light or directions or anything.
Well, if Saint Rachel Corrie is a pancake, what is Saint Trayvon?
> His best work was American Graffiti, playing a dipshit.
Because it required no acting skills. He just played himself...
Conservatives have a double golden opportunity right now, to loudly proclaim to Hispanics-Latinos that every single liberal Democrat attacking Zimmerman racially despises Hispanics-Latinos; and that conservative Republicans are Zimmerman's strongest supporters.
Hey, Hispanics-Latinos, think about *that* when you vote.
The anti-gun left in America can go straight to Hell.
F U Dreyfus. Yet another Hollyweird Hasbeen that insists on opening his piehole and effectively pissing off half of America with his leftist-agenda-driven stance.
"His best work was American Graffiti, playing a dipshit."
What made you think he was playing (acting)? Now we know.
They need to be asked the question, over and over again, and be made to answer before spouting any more drivel -
What is it you want to do to us that requires we be unable to resist?
You have a valid point
My experience is that many Liberals privately are okay with the verdict as such. It is the so called liberal "leaders" and "activists" and "media pundits" who continue this charade because they have painted themselves into a corner and are not about to admit that the Zimmerman case is not the civil rights watershed moment they hoped. So they continue to push the Zimmerman as racist thug narrative. No facts, no jury finding is going to change their notions of reality.
What do you think of that? Anything to add or subtract?
I need to remember to read everything before posting.
I think you have revealed the core values of modern liberalism - although more than half the time it's the young boy parking the cars they are really after. :)
"What is it you want to do to us that requires we be unable to resist?"
I think it's pretty obvious what they want us to do. Bow down, give in, submit or be killed.
We have a black racist president and a black racist attorney general. The left has to do something to convince blacks that they are still being held back by whitey.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.


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Wow! Runners World, Men's Health, just to name a few. Looks like B&N is stepping up with new additions. Too bad most are not compatible with the original Nook. It's been out for maybe a year and seems to be already outdated. Way to go Barnes, I don't want to speak for everyone but this early adopter thinks this sucks.
I won't be holding my breath that 1.5 will make it better. However if it does, I will gladly admit I was wrong.
Could we perhaps get a way to filter out the Nookcolor-only mags when we browse the site? It is very annoying to go through magazine after magazine saying "Nope, I can't read this one either." I understand the reasoning behind some of them, but honestly there's no reason something like Newsweek should only be available in color.


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A child and a child molester walk into a forest together. The child turns to the molester and says, "Boy, these woods are scary." The molester says to the child, "You think you're scared? I have to walk out of here alone."
What's the difference between parsley and pubic hair? Nothing. Push them both over and keep on eating.
Q: In a circle of lesbians, how can you tell which one is the toughest and roughest?
A: She's the one who rolls her own tampons and kick-starts her vibrator.
Q: How do they know that Paul Walker had dandruff?
A: They found his head and shoulders in the glove box.
Q: What is the difference between a gay guy and a refrigerator?
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Norfolk barricade situation ends after 67 hours
Although authorities haven't identified the suspect, neighbors and people who know him identified the suspect as Larry Wooster.
Body cam video of Marcus Vick arrest in Newport News released
Vick is seen talking with officers and on the phone for around 15 minutes before taking off out the front door of OneLife Fitness.
Family of man fatally shot by Stephen Rankin in 2011 attends murder trial
Stephen Rankin, an officer with the Portsmouth Police Department at the time, was cleared in the shooting death of Kirill Denyakin.
Judge: Reagan shooter can leave hospital to live in Williamsburg
John Hinckley Jr. is ready to live in the community, Judge Paul L. Friedman ruled Wednesday.
Live Twitter Blog of Rankin Murder Trial
Former Portsmouth police officer Stephen Rankin is on trial on a charge of first-degree murder. WAVY News 10's Deanna LeBlanc is live tweeti…
An annual tradition: The 91st Chincoteague Pony Swim
The ponies will be guided through the Assateague Channel to the eastern side of Chincoteague Island.
Redskins report to training camp in Richmond
Bruce Rader is in Richmond for his 37th consecutive year of covering Redskins Training Camp.
Freddie Gray officers suing prosecutor Marilyn Mosby
On Wednesday, Mosby announced that charges against three officers still facing trial were being dropped.
Virginia Beach pitcher stymies Tides at Harbor Park
Shawn Morimando from his Virginia Beach made his Harbor Park on Wednesday and that was bad news for the Tides.
Democratic VP candidate Tim Kaine to hold campaign rally in Richmond
Tim Kaine will return to his hometown of Richmond to host a campaign rally on Monday.
Getty Mart robbed at gunpoint in Portsmouth
Portsmouth Police are investigating an armed robbery at the Getty Mart on George Washington Highway.
Virginia Beach's Tayvion Land commits to Virginia Tech
Rising sophomore Tayvion Land announced that he will attend Virginia Tech in 2019.
Longwood University prepares for only Vice Presidential debate of 2016
Longwood University prepares for only Vice Presidential debate of 2016
Saints help flood victims before training camp kicks off
Saints help flood victims before training camp kicks off
Police charge Marion parents after toddler overdoses twice in a week
Police charge Marion parents after toddler overdoses twice in a week
Documents: Kaylee Sawyer hit by car, body dumped
Part-time college public safety officer arrested, charged with murder in case
Photos: Storm damage in Gloucester
The National Weather Service says there have been no reports of injuries in the area, but did say there was some structure damage.


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This gene encodes a putative RNA binding protein. Mutations in this gene, specifically a t(11;22)(q24;q12) translocation, are known to cause Ewing sarcoma as well as neuroectodermal and various other tumors. Alternative splicing of this gene results in two products.
bK984G1.4, AC002059.7, EWS
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PC JewellersView mapKarol Bagh, New Delhi, Delhi(Verified Supplier)
Call Us: +91-8042955814
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PC Jeweller started operations in April 2005 with one showroom at Karol Bagh Delhi. It is a first generation business promoted by two brothers- Sh Padam Chand Gupta and Sh Balram Garg.The company however, had a vision of expanding its presence in the retail segment .
The company's business model consists of opening large format, stand alone stores at high street locations. It's stores stock a wide range of jewellery across all price points, with an increasing focus on diamond jewellery. The company sells only hallmarked jewellery and certified diamond jewellery. This assurance on quality & purity along with transparent & customer friendly policies has enabled PCJ to become an established and trusted brand name in a short time span.
It has accordingly been opening showrooms at regular intervals and today has a strength of 41 stores spread over 33 cities.
The most valued asset is our relationship with the clients, which has been built over years by giving certified quality, latest designs, transparency in dealings and best personalized customer service. Proactive and timely research and creation of world class jewellery and also guidance to its customers to enable them to take correct purchase decisions.
The company is confident that its trust on diamond and other high margin jewellery along with customer oriented marketing initiatives would continue to help grow its top line as well as bottom line.
Mr. Padam Chand Gupta, Chairman of the Company has our three decade experience in jewellery.
Mr. Balram Garg, Managing Director of the Company can easily be called the goodwill ambassador of this group. A man of clear vision and strong decision, Mr. Garg's approach in business rests on his belief that nothing is impossible.
Fact Sheet
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101 to 500 People
Contact UsPC Jewellerskavita Call Us: +91-8042955814
View map270893 karol bagh new delhi
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The 2016 Tower Rock Run is scheduled for August 13, 2016. The U.S. Forest Service Permit has been submitted, but not yet approved. Buses are reserved and sponsorship requests are in progress. The Shirt design is in process. More information will be posted shortly.
Online Registration through RaceEntry.com
If you haven't started training yet for this year's Tower Rock Run it's not too late! Thanks to new Sponsor Prana Endurance Training, we have several training regimens that can help you get ready for this years race!
5K Beginner's Training Program
5K Walker Training Program
10K Beginner's Training Program
10K Walker Training Program
Local Accommodations and Campgrounds
Map for Starting Point & Parking
*Permitted by the Ashley National Forest
This Page was last updated: June 25, 2016


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Very good fit and appearance
Reviewed By John S (West Creek, NJ) Reviewed for a 2006 Honda Ridgeline —7/6/2016 6:22 AM
Good fit and ease of install that took about an hour plus. When finished it looked like it could have been factory installed.
Reviewed By Cindy K (PANAMA CITY, FL) Reviewed for a 2009 Infiniti FX35 —7/21/2016 8:39 PM
Matches the interior of my 2009 Infinity FX 35 perfectly. I went with the darker color which is a perfect match. I like the texture and feel of this cover much better than the faux suede ones everyone else has.


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|Reviews for Death of the Discworld
| bleeb90 chapter 2 . 9/24/2015
I loved it!
| Konda020946 chapter 2 . 11/27/2014
You keep the tradition allive very good
| MeinNameIstHase chapter 2 . 2/6/2014
Harry as Death is nearly always funny. And you excel.
| Zlatka chapter 2 . 7/31/2013
Great :))
| frytrix chapter 2 . 4/29/2013
great story, update soon.
| Nimbus Llewelyn chapter 2 . 5/31/2012
Weird, but funny.
| lazyguy90 chapter 2 . 2/14/2012
Haha, oh this is a lot of fun. Great work.
| GodricGeoffreyGryffindor chapter 2 . 2/7/2012
Theta, of course, is the first letter of "Thanatos" when spelled in Greek letters. Omega would also be a symbol of Death, or at least, the End of Life, since Omega is the last letter of the Greek alphabet and therefore signifies the End of anything. An inverse Ankh would simply be an upside down one.
I don't think the tattoos added anything, but I thought the Deathly Hallows changing to reflect the times and choosing the next avatar of Death like a wand was funny. And the previous Thanatos gets to be just Theodore and play with pretty French girls on nude beaches.
| GodricGeoffreyGryffindor chapter 1 . 2/7/2012
"Yeah," Henchgirl agreed, "your ears have gone all pointy." Just what Harry needs: to go elfish in addition to everything else.
| lokobookworm95 chapter 2 . 7/26/2011
Are you going to continue this? 'Cause it's absolutely histerical, and I really want to read more Harry-as-Death stories! Nice job!
| PhoenixFTW chapter 2 . 1/24/2011
Very funny, you should update it.
| aalens chapter 2 . 9/1/2010
Your Mr Black fics are as good as Rorschach's Blot's - and that is really saying something.
| anon chapter 1 . 1/7/2010
Telomeres cap the ends of DNA. Telomerase just makes / maintains them. And being a Bona-fide gene, it is encoded in the genome like any other gene. Making it isn't so special, just turn on the gene.
| Lord Sia chapter 2 . 10/18/2009
Epic. Love the "Make A Wish" series, greatest work on this site, and yours is a worthy addition.
| Von chapter 1 . 8/29/2009
(Hysterical on the floor)
This was so beyond awesome.
"And I'm going to take better care of my books in future," he resolved
Usually I just say 'Mr Black' and people are like 'oh, him' …except it's more like 'oh god no not Mr Black!' multiple exclamation marks.
Beyond the pentacle were a bunch of somewhat nervous-looking people Harry instantly identified as wizards from the ridiculous robes, long beards and general air of a complete lack of sense.
All had me rolling on the floor (or therabouts) laughing.
Best Death Cameo ever. I especially liked your Susan - she seemed perfectly balanced between her actual hardcore character and the interest in a fellow 'subbie'.


text:
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WHAT'S DOING IN; Brussels
Published: May 21, 2000
(Page 2 of 2)
The Cathedral of St.-Michel and Ste.-Gudule (20, place Ste.-Gudule), recently reopened, has never looked better. If you approach it from the winding streets of the old city, it suddenly looms above you, a heavenly apparition in pure white Gothic stonework. Until Sept. 20, the interior will be enhanced by 18 extraordinary high-warp tapestries, loomed in Brussels 500 years ago and on loan from the Spanish Crown. Tickets at the cathedral's ticket office, open Monday to Friday, 10 a.m. to 6 p.m.; Saturday, 10 a.m. to 4 p.m.; Sunday, 2 to 7 p.m. $6.80. (Guided tours in English on weekdays.)
Where to Stay
Reduced rates given in parentheses apply on weekends and mid-July to the end of August.
Le Dix-septieme, 25, rue de la Madeleine, (32-2) 502-5744, fax (32-2) 502-6424, in a 17th-century house is a tasteful haven. The 30 rooms, all different, feature wooden floors, Oriental carpets, exposed beams. Excellent service. Doubles start at $160 ($147), buffet breakfast included.
Manos Residence, 102, Chaussee de Charleroi, (32-2) 537-9682, fax (32-2) 539-3655), consists of two art-filled town houses. Nine of the 38 rooms are reached by a spiral staircase to the fourth floor (which connects with the other, elevator-equipped section). The breakfast room and bar open onto extensive gardens. Doubles with bath cost $188 ($91); suites are a bargain at $308 ($148).
Budget: Hotel Welcome, 5, rue du Peuplier, (32-2) 219-9546, fax (32-2) 217-1887, proudly claims to be Brussels' smallest hotel, but the six rooms offer most of what anyone might need, including king-size beds. The small inconveniences (no elevator) are made up for by the youthful enthusiasm of the owners, Michel and Sophie Smeesters. Breakfast room and restaurant. Doubles from $59 to $93 (no weekend rates).
The Galia, 15-16, place du Jeu du Balle, (32-2) 502-4243, (32-2) 502-7619, right on the flea market, is not for the faint-hearted but has its own kind of jaunty charm. The elevator is slow but gets you there, and the 24 rooms are small but all have showers. There's a lively, skylighted tavern behind the reception. Doubles from $43 to $64 (no weekend rates).
Luxury: Le Meridien, 3, Carrefour de l'Europe, (32-2) 548-4211, fax (32-2) 548-4080, has an undeniable Parisian chic, reflected in the smartness of the 224 red, green or blue rooms, the round marble lobby with its chandelier, and the restaurant, l'Epicerie, whose Mediterranean-flavored cuisine matches the colorful Limoges china. Doubles cost $318 ($116), not including breakfast.
Radisson SAS, 47, rue du Fosse-aux Loups, (32-2) 219-2828, fax (32-2) 219-6262, has a young, can-do spirit, and the 281 spic-and-span rooms come in four styles. The greenery-filled atrium is a pleasant oasis, and the Sea Grill restaurant, one of Brussels' best, with two Michelin stars, will close July 21 until Aug. 15 for renovations. Doubles from $295 ($134).
Where to Eat
Unless otherwise indicated, restaurants are closed Saturday at lunch time and Sunday, and for two weeks in July or August.
Le Bistrot du Mail, 81, rue du Mail, (32-2) 539-0697, is a cozy, casual place with ox-blood red walls where most of the clientele are regulars. Diners generally stray in late, 9 to 9:30 p.m. We loved the sea scallops with caramelized endives, the roast turbot with asparagus and potatoes crushed in olive oil, and lamb from the Pyrenees. Lunchtime regulars go for the plat du jour at $7.85. Dinner for two with wine about $90.
Le Passage, 13, avenue J. &. P. Carsoel at the Place St. Job in Uccle, a 20-minute cab ride from downtown, (32-2) 374-6694, is my favorite neighborhood restaurant; Michelin handed it a star this year. The decor is simple but the cuisine highly inventive: swordfish carpaccio, lasagna of roast salmon and langoustines, lightly curried caramelized apple. Dinner with wine for two is $100. Prix fixe menus are bargains: a two-course lunch, $14; four-course dinner, $29.
L'Atelier de la Truffe Noire, 300, avenue Louise, (32-2) 640-5455, always packed, is the fast-food outlet of Luigi Ciciriello, proprietor of the eponymous astronomically expensive restaurant. The Atelier, crammed into a former patisserie, is open 8:30 a.m to 6:30 p.m. Monday through Saturday (Sunday 10 a.m. to 5 p.m.). The enormous choice ranges from a $3.40 salami sandwich to truffle-and-goose liver in puff pastry ($55). More typical prices for a main course are $11 to $16, wine $4.50.
For a budget meal, a good choice is 't Kelderke, in a subterranean brick vault at 15 Grand-Place, (32-2) 513-7344, open daily from noon to 2 a.m. The plat du jour is an unbeatable $6.70. Stoemp -- a potato and vegetable mash -- with sausages and other Brussels specialties served in generous portions takes pride of place. Two can dine in style for $45, or half that with a bit of care.
And thousands of Bruxellois lunch every day for less than $2.50 on copious French bread sandwiches, stacked high in snack shops and butcher shops all over town.
The preference of chocolate gourmets in this city of great chocolate has switched from milk or white chocolate to ever darker cacao in search of the pure chocolate taste. Three chocolatiers are ahead of the rest in this pursuit: Wittamer (6 Place du Grand Sablon), past masters at fresh-cream pralines, $8.50 for 250 grams; Galler (44 rue au Beurre near the Grand-Place), whose Extreme is 70 percent cacao, $7 (250 grams); and a newcomer, Pierre Marcolini (39 Place du Grand Sablon), where you can taste before you buy from a flowing chocolate fountain, $9 (250 grams).
Photos: Dancing lessons at the Bal Moderne. Russian accordion, at the Musical Instruments Museum. Pageantry at the Ommegang procession. Didier Plasch, owner of Bistrot du Mail. (Ommegang Oppidi Bruxellensis (procession); Pierre Mardaga/Musical Instruments Museum (inset)); (Jock Fistick for The New York Times (dance, restaurant)) Chart: ''Vital Statistics'' lists travel information and statistics on Brussels. (Sources: Runzheimer International, Belgian Tourist Office, Fodor's World Weather Guide, local businesses) Map of Brussels shows tourist attractions and points of interest.


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Officials say Oklahoma State basketball player Tyrek Coger died from an enlarged heart after a 40-minute team workout on the football stadium stairs in hot weather
Clemson, Florida State in control of ACC's Atlantic Division entering 2016 season
Maty Mauk understands that second-guessing might accompany his second chance at Eastern Kentucky
Atlantic Coast Conference Commissioner John Swofford says the league has extended its media deal with ESPN through the 2035-36 season, a deal that includes the launch of an ACC TV channel in three years
The good news for the Big 12 Conference is that there is no shortage of suitors as it considers expansion
This is no longer the local-guy-makes-good story. Josh Tiven is a veritable veteran now, six years...
John Elliott, the former NFA star, divides time living between Westerly and Jupiter, Fla., but his...
The Big 12 presidents have directed Commissioner Bob Bowlsby to evaluate schools that are interested in joining the conference
Pat Summitt was remembered as a loving mother, a loyal friend and a tireless fighter as well as a champion coach Thursday in a public ceremony honoring the person who built the Tennessee women's basketball dynasty
Pat Summitt is being honored posthumously Thursday in the basketball arena where she orchestrated some of her greatest victories
Pat Summitt's fight against Alzheimer's disease continues, and has even gained a little momentum since her death
Former UConn star Breanna Stewart was honored as the collegiate woman athlete of the year earning the Honda Cup
Local roundup: Waterford wins to clinch spot in N.E. Babe Ruth tourney semis
New London Legion falls 1-0 in eight innings at state tourney
Yankees beat Giants, discussing deal to send Chapman to Cubs
Noah Budzik's RBI single in the bottom of the eighth inning lifted Rocky Hill-Cromwell-Portland to a 1-0 win over New London on Sunday in the Northern Division Super Regionals of the state American Legion baseball tournament.
Waterford took all the drama out of its game early at the New England Babe Ruth 13-year-old baseball tournament on Sunday.
New London won its opener in the Northern Division Super Regionals at the American Legion baseball state tournament, beating Tolland 6-2 on Saturday.
The Chicago Cubs have acquired hard-throwing reliever Aroldis Chapman in a trade with the New York Yankees, giving the NL Central leaders a boost as they try for their first World Series title in more than a century.
The NFL has cleared former Broncos QB Peyton Manning after a seven-month probe into allegations made in an Al-Jazeera America documentary.
6 p.m., WICH (1310-AM) — NYP: Connecticut Tigers at Mahoning Valley Scrappers in a doubleheader.
7 p.m., NESN, ESPN, WTIC (1080-AM), WEEI (103.7-FM) — MLB: Detroit Tigers at Boston Red Sox.
7 p.m., SNY, WOR (710-AM) — MLB: St. Louis Cardinals at New York Mets.
8 p.m., MyTV9, WFAN (660-AM), WXLM (980-AM) — MLB: New York Yankees at Houston Astros.
10 p.m., NBA TV — Women's exhibition: United States vs. USA Select Team from Los Angeles.
7:30 p.m., ESPN2 — CFL: Montreal Alouettes at Toronto Argonauts.
7:30 a.m., ESPN2 — International Champions Cup: Manchester City vs. Manchester United from Beijing.
11 a.m., Tennis Channel — Rogers Cup from Montreal and Toronto.


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The beam errors of an 11 bar laser diode stack fitted with fast-axis collimator lenses have been corrected by a single refractive plate, produced by laser cutting and polishing. The so-called smile effect is virtually eliminated and collimator aberration greatly reduced, improving the fast-axis beam quality of each bar by a factor of up to 5. The single corrector plate for the whole stack ensures that the radiation from all the laser emitters is parallel to a common axis. Beam-pointing errors of the bars have been reduced to below 0.7 mrad.
© 2006 Optical Society of America
The effectiveness of laser diode bar stacks in many applications, such as pumping of solid-state lasers and direct use in material processing, is limited by the poor beam quality associated with current commercial stacks. In this paper, we report the development of a technique for improving beam quality by characterising beam imperfections of a stack, and based on that information, fabricating a custom optical corrective plate that removes the effects of a series of opto-mechanical errors, which were introduced during the original fabrication of the stacks. Diode bars are typically fabricated with 25 emitters of 200 μm width along a 10 mm bar of semiconductor, which is then solder-bonded to a micro-channel water-cooled heat sink. Commercially produced units, emitting 50–100W per bar, are stacked on typically 1.8 mm pitch to build up a total laser power of 500–1000 W. For many applications, an individual fast-axis collimator (FAC) lens is attached for each bar at the manufacturing stage. Currently, plano-acylindrical lenses are used to provide low aberration collimation for the high numerical aperture fast-axis beam. Brauch et al. [1] provide a good review of the optical issues of bar stacks and their applications.
The poor effective beam quality of diode bar stacks is a consequence of the practical imperfections in manufacturing and mechanical mounting for the bars and FACs at the micron level, rather than the intrinsic properties of the beams from individual lasers emitters in a bar. The cylindrical lens for each bar introduces angular aberrations that produce a local radiance loss of a factor of 2 to 3, although this may be improved with modern lens technology. The "smile" effect, whereby the semiconductor bar is bent by differential expansion during solder bonding, prevents the collimation lens being correctly positioned for all points along the bar, resulting in beams with variable pointing direction. Also, errors in attaching the FAC to the heat sink with the required positional accuracy further degrade the angular spectrum of the emitted light. There is also the problem of stacking the individual diode bars accurately enough to keep a common radiation direction for all bars. In many applications of the laser diode stacks, subsequent aperture filling, beam shaping and beam combining optics are required. The spread into a much larger volume of phase space than the theoretical minimum, mainly through errors in ray angles from the FAC, increases the design difficulty and reduces the efficiency for the subsequent beam conditioning optics, and fails to transfer the average radiance at the facet to the output application end.
Once a diode stack is built, the beam errors are fixed for a given average power output and operating temperature. The fixed nature of the errors allows for correction if a suitable optical element can be made, placed close to the output plane where beam errors are predominantly angular. To demonstrate this, we report the use of a commercial diode bar stack made by OptoPower Corp., which consists of 11 bars vertically stacked with a 1.82 mm bar pitch, emitting an overall power of 440W cw. Each bar is fitted by the manufacturer with a plano-acylindrical FAC which we measured to be 1.5 mm aperture and 0.9 mm effective-focal-length, similar to lenses available from several manufacturers.
Using the set-up in Fig. 1, we have assessed the severity of the various sources of beam error for each bar with the stack operating at full power. A slit formed by two mirrors, which are mounted on a micrometer stage (not shown), selects a single bar at a time, allowing the beam to propagate towards the screen at the left whilst deflecting the rest of the beams onto beam dumps. A cylindrical lens projects a slow-axis image of the selected bar on to a diffusing screen located 2 metres away. In the fast-axis direction, the beam is a good approximation to the far-field at this distance. A CCD camera connected to a computer is used to record the image from the screen.
Fig. 1.
Figure 2(a) shows images for each bar in the stack for the condition as delivered by the manufacturer and Fig. 2(b) show images for the same bars after a correction has been applied, which is explained later. Each beam image has dots corresponding to the slow-axis imaging of the 24 broad area emitters on the bar. In the fast-axis, the bar images are all significantly different due to differing combinations of opto-mechanical errors. The fast-axis M2 factor measured for the collective beam from each bar ranges from 5.5 to 15.5, with a mean value of 10.4 for the 11 bars.
Fig. 2.
The varying beam shapes result from different combinations of errors for each bar. The lens attachment errors – defocus, transverse offset and twist – lead to beam pointing and beam size variations and image rotation. Imperfections in the fabrication of the cylindrical collimator lens or poor aberration correction in the lens design lead to break up into side-lobes or fringes, as clearly seen in Fig. 2(a) for bars 1, 2, 5, 9, 10 and 11. The departure of the semiconductor substrate from flatness, or microlens bending, gives rise to the bent far-field known as "smile". As a result, the intensity distribution is modified from the expected gaussian-like profile and straight line image in the beam shapes shown in Fig. 2(a), with corresponding M2 values much larger than expected for the near diffraction-limited beams available directly at the emitting facet.
Fig. 3.
Fig. 4.
Since the beam errors are both pointing errors and local aberrations, we have used a wavefront sensing method based on the Hartmann technique [2] to measure the fast-axis wavefront variation at a plane close to the FAC output surface. This measurement was performed using a sensing device built in-house, which has a spatial resolution of 40 μm, an angular sensitivity of 19 μrad and a dynamic range of ~2600. By using this method, we obtain the local wavefront tilt, which is then numerically integrated as explained in Ref. [2] to obtain the Optical Path Difference (OPD) in the fast-axis. With this information we calculate the surface depth required for a refractive correction surface fabricated in silica, which will eliminate the OPD across the fast-axis. This OPD correction is applied where significant laser intensity is detectable. The required corrective surface for bar 1 is shown in Fig. 3 as an example. This surface shape data is translated by computer into cutting instructions for a specialised, high performance CO2 laser machining/polishing workstation. As described in Ref. [3], the optical surfaces are fabricated by raster scanned, pulsed CO2 laser ablation [4] followed by laser polishing [5], using a 50μm spot diameter and 10μm raster pitch. Since publishing [4], we have significantly enhanced the machining process by developing a complex control system to keep the CO2 laser stabilised on a single line and to control the dispensed energy in each laser pulse. As a result, we are now capable of fabricating smooth surfaces of arbitrary shape up to 40 μm deep with a depth resolution of 100 nm. After laser polishing [5], the measured loss outside a scatter cone angle of 10mrad is 0.5% at 940nm. A similar optic fabrication process, but on a much smaller scale, has been reported [6] to correct a single laser emitter, using excimer laser ablation of a polymer surface on a collimator lens.
The laser micro-machining produces 11 correction zones, one for each of the bars, on a single substrate. Each correction zone is a generally smoothly-varying surface over an area of 11 mm × 1.6 mm, with a surface height range of typically 10 to 15 μm. The prescription of the zones is designed to ensure all the bars have beams aligned along a common axis. The corrective plate is aligned using a micro-positioning stage at the plane of the wavefront measurement, and can be fixed satisfactorily using UV-cured glue. Relative misalignment of the stack and correction plate of ±5 μm in the fast-axis, ±15μm in the slow axis and ±250 μm in the proximity to the measurement plane are observed to produce noticeable degradation in the quality of the correction. It should be noted that such tolerances are far more relaxed than for the FAC lenses.
The effectiveness of the correction process for the whole stack is evident from Fig. 2(b), which shows the correction of the bar images in Fig. 2(a). The bars images are now straight, the side lobes are effectively removed and the central lobe is far brighter. Figure 4 shows an example of the uncorrected and corrected wavefront for one emitter in bar 1. The wavefront OPD range has been reduced from ~4λ to <λ/2 by the correction at 940nm. The correction is effected on single emitters by reducing aberrations and on bars by eliminating the smile. The fast-axis beam profile for a single emitter is shown in Fig. 5(a). The removal of the errors has transferred light from the tails into the main beam yielding a narrower beam with twice the peak intensity. Results for a whole bar demonstrate both aberration correction at emitter level and removal of overall bar smile. Figure 5(b) shows the transformation of the beam profile for bar 6 from a broad distribution with a step into a single-lobe with less than 3 times the divergence of the uncorrected beam and about 3 times the peak intensity.
Fig. 5.
In terms of the M2 factor, the bars are improved by more than a factor of 5. For example the beam in Fig. 5(b), which had an uncorrected M2=13.5 is now improved to 2.5. In terms of the smile effect (departure from straightness) the worst affected (bar 6) has been reduced from 3.3 μm to <0.4μm. The residual smile effect for all bars in the stack is found to be ≤ 0.4μm, while the bar average pointing errors have been reduced to 0.7 mrad rms.
As a figure of merit for the achieved correction we present the Power-In-The-Bucket (PITB) curves for the uncorrected and corrected version for one bar in Fig. 6(a) and for the whole stack in Fig. 6(b). For one bar, the angle that contains 80% of the power has been reduced by 4.3 times and for the whole stack it was reduced by 3.2 times.
Fig. 6.
A significant part of the improvement comes from the near-elimination of the smile effect, which was once considered not compensatable [1]. In the past, limited smile compensation has been reported using mechanical deflection of the cylindrical lens [7] or rotation of a separate slow-axis cylindrical lens after fast-axis collimation [8], but neither is very practical for large diode stacks. We believe that the correction plate technique solves a problem that has existed since the first development of diode bars and which manufacturers still struggle to eliminate.
The diode stack beam correction reported in this paper was achieved with an OptoPower diode stack, bought in 1998, which we believe exhibits most of the problems that could be present, making it a good test stack to demonstrate this technique. Since then, FAC lenses with near-diffraction-limited performance have appeared in the market; also manufacturers of stacks have greatly improved the alignment accuracy of the FAC lenses. However, new stacks may still suffer from significant smile effect, an error that degrades the high beam quality once available at the output facet of the bars. We have observed this in a range of newer commercial stacks purchased in the last few years, which we have also corrected.
In conclusion, we report a correction process for laser diode stacks that greatly reduces smile, lens aberrations and beam pointing error, to the point where these no longer limit optical design for beam transfer and brightness delivered to an application. We believe that this technique can significantly increase the brightness of the current generation of commercial stacks. Corrected stacks will enable improved beam handling and combining, such as beam interleaving, wavelength combining and beam reformatting.
We acknowledge the help of A R Holdsworth for early diode characterisation measurements and Roy McBride (PowerPhotonic Ltd.) for the fabrication of some corrective plates. The research was funded by the UK EPSRC. J.F. Monjardin gratefully acknowledges funding from CONACyT México and from the CICESE Research Institute.
References and links
1 . U. Brauch , P. Loosen , and H. Opower , " High-power diode lasers for direct applications ," in High Power Diode Lasers , R. Diehl ed., ( Springer-Verlag Berlin Heidelberg , 2000 ), pp. 303 – 368 . [CrossRef]
2 . I. Ghozeil , " Hartmann and other screen tests ," in Optical Shop Testing , D. Malacara ed., ( Wiley , 1992 ), pp. 367 – 396 .
3 . K. M. Nowak , H. J. Baker , and D. R. Hall , " Pulsed-laser machining and polishing of silica micro-optical components using a laser and an acousto-optic modulator ," in Laser Micromachining for Optoelectronic Device Fabrication , A. Ostendorf ed., Proc. SPIE , 4941 , 107 – 112 ( 2002 ). [CrossRef]
4 . G. A. J. Markillie , H. J. Baker , F. J. Villarreal , and D. R. Hall , " Effect of vaporization and melt ejection on laser machining of silica glass micro-optical components ," Appl. Opt. 41 , 5660 – 5667 ( 2002 ). [CrossRef] [PubMed]
5 . K. M. Nowak , H. J. Baker , and D. R. Hall , " Efficient laser polishing of silica micro-optic components ," Appl. Opt. 45 , 162 – 171 ( 2006 ). [CrossRef] [PubMed]
6 . T. Jitsuno , K. Tokumura , N. Nakashima , and M. Nakatsuka , " Laser ablative shaping of plastic optical components for phase control ," Appl. Opt. 38 , 3338 – 3342 ( 1999 ). [CrossRef]
7 . A. R. Holdsworth and H. J. Baker , " Assessment of micro-lenses for diode bar collimation ," in Laser Diode and LED Applications III , K. J. Linden ed., Proc. SPIE 3000 , 209 – 214 ( 1997 ).
8 . N. U. Wetter , " Three-fold effective brightness increase of laser diode bar emission by assessment and correction of diode array curvature ," Opt. Laser Technol. 33 , 181 – 187 ( 2001 ). [CrossRef]


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