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Your choice of either solid, low-, or high-resistance grounding is based on the power system application and degree of power interruption tolerated.
Solid, low-, or high-resistance grounding? That is the question asked by those involved in the design or retrofit of power systems. The answer depends upon certain important factors. To make the correct choice, the designer must have a complete understanding of system configurations, favorable performance traits, and drawbacks. Also required is the relative importance of the powered process or load.
The table shown on the facing page includes a comparison of the characteristics of these various grounding methods. Let's look at them more closely.
Historical information
Most older industrial plants were powered by ungrounded, 3-phase, 3-wire, delta power systems. Many of these systems are still in use today. This system choice was based on two factors. First, it made the most efficient use of conductor copper. Second, no fault current flowed when the first ground-fault occurred, which was, and still is, considered an advantage in some applications, although a shock hazard is introduced.
However, multiple motor failures in numerous industrial plants were seen and were due to severe overvoltages caused by arcing or resonant ground faults on the ungrounded systems. To prevent these overvoltages, many power system neutrals were grounded, usually solidly. There were many factors that contributed to the change to solidly grounded systems and these factors are still important today.
First, solid grounding very effectively limits the maximum phase-to-ground voltage. Second, it allows phase-to-neutral loads to be served without encountering dangerous neutral-to-ground voltages under ground-fault conditions. Third, simple and effective ground relaying systems can be used to isolate the defective portion of the system under ground-fault conditions.
Solid grounding limitations
There are, however, some limitations to solid grounding. In medium voltage (MV) systems (2400V through 35kV), even with good ground-fault relaying, the damage at the point of fault can be excessive. In fact, this problem led to the common use of low-resistance grounding, which allows the passing of anywhere from several hundred to several thousand amperes of ground-fault current. This practice reduces fault damage to acceptable levels while maintaining enough ground-fault current flow to effectively relay off the defective portion of the system.
In addition, solidly grounded, low voltage (LV) systems in the 480 to 600V range have two other problems. The first problem stems from application concerns. Some users prefer to maintain service, if possible, with a ground fault present on the system, or at least to arrange for an orderly, controlled shutdown. This is especially true for such continuous process industries as electric power generation, oil refining, chemical and steel manufacturing, and the paper industry. Since many of these power systems are worked hot, electricians are exposed to a considerable flash hazard from a possible line-to-ground fault caused by a misplaced tool.
Second, since most such systems rely on the phase overcurrent devices to protect against ground faults, it's possible to have a destructive arc of several thousand amperes in magnitude for several minutes duration without initiating an automatic trip.
To overcome the problems of unwanted shutdown, flash hazard, and burndown while still maintaining the transient overvoltage protection of a grounded system, high-resistance grounding was developed.
Pro high-resistance arguments
High-resistance grounding involves the grounding of the system neutral through a resistance that limits ground-fault current flow to a value equal to or slightly greater than the capacitive charging current of the system. This value is chosen because it is the lowest level of ground-fault current flow at which system overvoltages can be effectively limited. Increasing the current flow improves overvoltage control at the expense of increasing damage at the point of fault; decreasing the current flow reduces point-of-fault damage at the expense of greater risk of overvoltage.
High-resistance grounding is applicable to LV and MV power distribution systems serving 3-phase, 3-wire loads or line-to-line, single-phase loads. It effectively controls transient overvoltages during ground faults, minimizes arcing damage and flash hazard at point of fault, and allows continued operation of the system with a ground fault present at voltages of 5kV and below.
Components of high-resistance grounding system
A high-resistance grounding system consists of five basic parts: a system neutral, a grounding resistance, a fault-detector and [TABULAR DATA OMITTED] alarm scheme, a fault-locating scheme, and packaging for these components. Strictly speaking, only the first two items are required; however, the grounding system's usefulness is severely limited without the other three items.
System neutral. By far the easiest way to obtain a system neutral is to use the neutral of a wye-connected power transformer or generator supplying the system. On any new system, it's recommended that this method be used.
On existing delta-connected systems (or on new systems that must be delta-connected to allow paralleling with existing systems), a neutral may be derived by using a bank of three small transformers connected in wye on the primary and in delta on the secondary. The primary voltage rating must be equal to the system line-to-line voltage since the transformers connected to the ungrounded phases will see that voltage under conditions of solid ground fault on one phase. The secondary should be rated 120V for convenience of fault detection. The kVA rating should be chosen such that the rated primary current of the transformer equals or exceeds 1/3 of the selected system ground current, since the ground current divides equally among the three transformers.
For example, if you decided to ground a 2400V system so that 10A of ground current can flow, the transformer size required is equal to the quantity 2400 times 10, divided by 3, or 8000VA. Thus, three standard 10kVA transformers would be used.
Grounding resistance. The grounding resistance determines the value of ground-fault current that will flow. Since the desired value is dependent on the system capacitive charging current, the charging current must be determined before the resistor can be selected. The only accurate method of determining this current for any given system is measurement.
Since measurement is not possible during the design stages of an installation, normal practice is to estimate the capacitive charging current, provide a tapped resister that allows several settings in the range of the estimated current, make the necessary measurements, and set the resister at installation time.
Sufficient data have been accumulated from system measurements to allow fairly accurate estimates of system capacitive charging currents for various systems.
Typical values of capacitive charging currents have been found to be as follows.
* 480V systems: usually less than 1A with maximum of about 5A.
* 2400V and 4160V systems: 2 to 7A.
* 13.8kV systems: 10 to 20A.
These values are for in-plant power systems, such as auxiliary systems for generating systems or distribution systems for industrial plants. Utility distribution systems would exhibit higher values because of the greater length of conductor involved.
(July 1994 issue, "What To Know About High-Resistance Grounding.")
Determining required resistance
After the system charging current has been estimated and a value of ground-fault current selected, the value of the required resistance is determined. For 480V systems, a very practical grounding resistor can be made from four 77 ohm resistors rated 750W, 240V each. These can be connected in various series-parallel arrangements to produce the appropriate current flow.
LV delta-connected systems. It's more common to connect a grounding transformer bank to the 480V secondary and insert the resistance between the neutral of this bank and ground, as shown in Fig. 1, with no load connected to the secondary. As shown, ground-fault current can be limited to 1.2A by a resistance of 277 divided by 1.2, or 230.8 ohms. Thus, three 77 ohm resistors connected in series will provide this value.
MV delta-connected systems. For MV systems having a power transformer with a delta-connected secondary, a grounding transformer bank is connected to the power transformer secondary, and the grounding resistance is connected in the secondary of this bank, as shown in Fig. 2. This permits the fault-detecting and locating circuitry components to be operated at the secondary voltage level. With this connection, the secondary current may be calculated by multiplying the transformer primary current by the transformer ratio. This is the current through the grounding resistor, and its value establishes the continuous current rating of the grounding resistor. The voltage across the resistor under ground-fault conditions is 1.732 times the secondary voltage of the grounding transformer bank, or 208V for a 120V rating. The grounding resistance required can be determined from these values of current and voltage. For the example shown in Fig. 2, the transformation ratio is 4160 divided by 120, or 34.67 to 1. For a fault current of 5A, primary current will be 5 divided by 3, or 1.67A; secondary current will be 1.67 times 34.67, or 57.9A. The required grounding resistance will be 208 divided by 57.9, or 3.6 ohms. This will be seen by the fault current as a high resistance when reflected in the primary.
MV wye-connected systems. For a power transformer with a wye-connected secondary, the primary of a single-phase grounding transformer is connected between the neutral point and ground, and the resistor is connected in the secondary circuit, as shown in Fig. 3. The primary voltage rating of the transformer must be at least equal to the line-to-neutral system voltage and may be equal to the line-to-line system voltage, if that is more convenient. The kVA rating must be chosen so that the rated primary current of the transformer is not exceeded by the system ground-fault current. The secondary voltage rating may be either 120 or 240V. The secondary current under ground-fault conditions will be the system ground-fault current multiplied by the transformer ratio. The secondary voltage under ground-fault conditions will be the system line-to-neutral voltage divided by the transformer ratio. Using these values, the resistance and wattage of the ground resistor can be calculated. The values shown in Fig. 3 are the results for a ground-fault current of 5A. Note that the ohmic value is different from that of Fig. 2, but the wattage required is the same.
As in LV systems, it's common practice for manufacturers to supply a tapped resistor that covers the range of expected values. Field measurements will determine the final setting.
High-resistance grounding do's and don'ts
The following guidelines should be followed when using a high-resistance grounding system.
* Use high-resistance grounding to limit transient overvoltages without shutting down grounded equipment on occurrence of first ground fault (5kV and below).
* Use sensitive ground-fault relays to trip breakers feeding faulted system elements at voltages above 5kV.
* Enforce maintenance procedures for locating and removing ground faults promptly upon detection.
* Test all systems for actual system capacitive charging current upon installation and set grounding resistor accordingly.
* Do not use high-resistance grounding where 3-phase, 4-wire loads must be served.
* Do not use high-resistance grounding as a substitute for proper system maintenance.
* Do not provide additional ground connections on other electrical equipment when using high-resistance grounding equipment. Ground only at grounding resistor.
EC&M Articles:
"What To Know About High-Resistance Grounding" July '94 issue.
Baldwin Bridger, Jr., P.E. is Technical Director, Powell Electrical Manufacturing Co., Houston, Tex. and past president of the IEEE Industry Applications Society.


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If you would like to add a personal touch, try
our amazing Card Generator...
Zalando, one of UK's biggest online shops has something for everyone; shoes, clothing, accessories and sportswear. If you're looking for all the latest must-haves, then Zalando is the place for you. With over 1,000 brands waiting to be discovered, why not check out www.zalando.co.uk today and bring some shopping joy to your home.
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2. Log in to www.zalando.co.uk under 'My Account'. Enter your gift card code in the field found on the 'My Vouchers'. You can also enter the voucher code directly at the checkout stage in the voucher code field. If you do not use the complete voucher value all at once, the remaining value will be credited to your Zalando account.
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subset: commoncrawl


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jonathan kawchuk
Atelier is a simple template that holds galleries, blogs, and other pages easily.
Page Alignment Options
Pages in Atelier can be aligned to the left or center of the page.
Blog Alignment Options
The blog page for Atelier can be customized to have a sidebar on the left, right, or none at all.
Multiple Navigation Sections
Atelier has the flexibility to create a hierarchy in the sidebar. To organize and emphasize projects from other pages, the template features two navigations: Main Navigation and Secondary Navigation. Gallery pages can be placed under the main navigation so that each collection of work has its own link in the navigation. Other pages such as the blog or contact page can be placed in the secondary navigation.


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If you're like me, you've got more than a few wine corks hanging around. Here's how to turn some of those corks into Christmas decorations in a few easy steps.
Step 1: Open up a favorite bottle of wine or grab a cork from the bag you're waiting to recycle (you do recycle your corks right?). If you're opening a new bottle, make sure to try to center the corkscrew so that you don't break the sides of the cork for aesthetic reasons.
Step 2: Purchase yourself some Small Screw Eyes from the local hardware store. 13/16 of an inch is a good size to make durable ornaments.
Step 3: Screw a Small Screw Eye into the top or bottom of the cork.
Step 4: I'm always out of hangers, so I picked up a set at the local pharmacy. You can also use things like string or yarn.
Step 5: Attach the hanger to the Small Screw Eye.
Step 6: Hang and have a happy holiday!
How to Turn a Cork into a Christmas Ornament in Six Easy Steps
If you're like me, you've got more than a few wine corks hanging around. Here's how to turn some of those corks into Christmas decorations in a few easy steps.
8 comments
Shona Milne Says:
I never knew you were into crafts. Love this idea.
Shona, wait until you see the cork wreath I'm working on.
alison Says:
Still waiting for your empty-wine-bottle-ornament Christmas tree...
alison, hmmm....the wheels are turning!
Unknown Says:
hah! I definitely can't wait to see that cork wreath.
I'm envisioning perhaps next year taking alison's challenge with a twist - a Christmas tree made entirely of wine bottles! I'm also thinking an empty demi-bottle might make a nice star on top of the tree and/or an ornament. Will need to look into that.
Co Dinn Says:
Reminds me of Ferdinand's cork tree:
Clearly the best and highest use for a cork!
Co, I was hoping to make another post about making garlands out of screwcaps but I think it will have to wait until another year!


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Interior Design Projects
Examples Projects Below
The place where you will use the chair is a restaurant, cafe or hotel, so your chair should be able to withstand heavy traffic. In addition, the model of the product to be selected is as important as its robustness. In addition, the chairs are manufactured from different materials for two different environments, external and internal.
Wooden Chairs, Metal Chairs, Metal or Aluminum Casting Chairs, Aluminum Chairs, Plastic Chairs and Fiber Chairs There are also many different material options within each material type.
|When evaluating outdoor garden furniture, you'll probably look for most of the features you're looking for on the interior tables, chairs, chairs and furniture, such as durability, comfort, design and of course the price. First of all, the garden furniture is exposed to all weather conditions and it is a must-have. Although there are no 100% weatherproof garden furniture, there are also durability differences depending on the materials used. Before deciding, we need to investigate the strengths and weaknesses of the various material options. You should pay attention to the compatibility of your personal preferences with the concept of your home or commercial environments for outdoor furniture.


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House passes death penalty repeal bill
Hartford — The state House of Representatives voted 86 to 62 late Wednesday on legislation that clears the way for Connecticut to become the 17th state to bring an end to the death penalty.
The bill, which last week passed the Senate on a 20-16 vote and is headed for Gov. Dannel P. Malloy's desk, abolishes capital punishment for future convictions, but keeps it in place for the 11 inmates currently on death row.
Instead of execution, worst-of-the-worst offenders convicted of "murder with special circumstances" would face life imprisonment without the possibility of parole.
Malloy released a statement, vowing to sign the bill.
"Going forward, we will have a system that allows us to put these people away for life, in living conditions none of us would want to experience," the governor said. "Let's throw away the key and have them spend the rest of their natural lives in jail."
Voting for the repeal bill were Democratic Reps. Ed Jutila of East Lyme, Betsy Ritter of Waterford, Diana Urban of North Stonington, Kevin Ryan of Montville and Elissa Wright of Groton.
Casting "nay" votes were Democratic Reps. Ernest Hewett of New London, Ted Moukawsher of Groton, Steve Mikutel of Griswold and Tom Reynolds of Ledyard.
"It was the right thing to do in a civilized society," Wright said afterward.
"For me it's a personal, moral issue," Ritter said.
The 151-member House took up the repeal bill at about 1:20 p.m. and lawmakers debated for more than 9½ hours.
The final vote tally was largely along party lines, with most Democrats in favor of repeal and Republicans opposed to it. The vote was closer this year than three years ago, when the House passed a similar repeal bill, 90 to 56.
Death penalty supporters tried unsuccessfully to attach amendments to retain the death penalty for certain offenses. There were proposed exceptions for a lethal act of terrorism, murder of a state trooper or local police officer, and murder committed in the course of a rape or a deadly home invasion.
"For the love of God, Connecticut is on the map for the worst home invasion in history," said Rep. Brenda Kupchick, R-Fairfield, who urged support for the failed home invasion exception.
The bill's opponents all but dominated the day's floor debate, often punctuating their speeches with grisly details of the infamous 2007 Cheshire home invasion and triple-slaying, and the terrifying years when serial killer Michael Ross was at large.
"We in this chamber are showing sympathy for the murderers and not sympathy for the victims' families," said Rep. Al Adinolfi, R-Cheshire, a death penalty supporter who lived five houses away from the home where Jennifer Hawke-Petit and her daughters, Hayley and Michaela Petit, were murdered.
In 2009, Hewett voted for the repeal bill that passed both legislative chambers but was vetoed by then-Gov. M. Jodi Rell.
But Hewett voted against this year's bill. What changed his mind about capital punishment, he said, was his inability to forget the heinous Petit murders and the 1999 killing of Karen Clarke and her 8-year-old son, Leroy Brown Jr., in their Bridgeport duplex.
"That really sent it home for me," Hewett said.
Clarke and Brown's killer, Russell Peeler Jr., is now on the state's death row.
In a floor speech, Hewett said it is perplexing to him that society would sanction killing during war combat or by law enforcement to ensure public safety, but not for convicted murderers.
"The death penalty is not about an eye for an eye or a tooth for a tooth, it's about holding that individual accountable for his actions and safeguarding innocent victims," Hewett said. "Is it so much to ask these violent predators to forfeit their life when they didn't give their victims a choice? I say no."
The House bill is nearly identical to the Senate bill passed last week. It creates new imprisonment standards for future Class A felony murderers convicted of "murder with special circumstances," what is currently known as a capital offense.
Under the bill, those convicted must be housed separately from other inmates, subjected to twice-weekly cell searches and must change their cells every three months. They would get no more than two hours a day outside their cells and would be allowed only "non-contact" visitation privileges. They could watch TV, but only basic channels.
Early in the debate, House Minority Leader Lawrence Cafero, R-Norwalk, grilled the judiciary committee's co-chairman, Democratic Rep. Gerald Fox of Stamford, about the constitutionality of the "prospective" legislation that aims to preserve the death penalty for the 11 current death row inmates.
Some bill opponents, including Hewett, contend that those now on death row inevitably will use the exception-granting language in the bill to get their death sentences commuted.
But many proponents say they're confident the courts will respect the legislature's intent to keep the death penalty in place for those 11.
The judiciary committee's other co-chairman, state Sen. Eric Coleman, D-Bloomfield, last week cited a New Mexico case as assurance.
Since 2009, New Mexico has had a prospective repeal on the books, and its highest court in a recent ruling allowed jurors the option of sentencing a convicted killer to death because his murders happened prior to the repeal.
But under questioning during Wednesday's debate, Fox allowed that the New Mexico Supreme Court did not weigh in on the constitutionality of executing someone once a prospective repeal is in place.
Critics say the constitutionality question is critical to determining whether today's death row would stay intact.
However, Fox cited three state court precedents, one dating to 1846 and the others to the 1950s, that led him to believe that today's court would honor the legislature's intent.
Nevertheless, Hewett criticized the future-crimes-only part of the bill, asking "What if we as a country abolished slavery prospectively?"
"Wait until you have the votes for total repeal," he said. "You will not have my vote, but at least you will have done it the right way."
Outside the House chamber, Moukawsher said he intended to vote against the repeal because the death penalty "is justice to victims."
He presented a hypothetical scenario: If law enforcement had a chance to shoot dead someone who is now a convicted murderer in the moments before the murders took place, such use of force likely would meet with approval from today's death penalty opponents.
"But once this crime happens, those lives become precious," Moukawsher said of the convicted murders. "I don't understand that."
The last person executed in Connecticut was Michael Ross in 2005, who waived his appeals. Prior to that, Joseph "Mad Dog" Taborsky was executed by electric chair in 1960 for a 1950s killing spree.
Stories that may interest you
Supreme Court lets Sandy Hook shooting lawsuit go forward
The Supreme Court is letting the lawsuit against the maker of the rifle used in the Sandy Hook Elementary School shooting go forward
ICE: Connecticut court security prevented detainment of man overstaying visa
Immigration agents say a Connecticut judicial marshal tried to prevent them from entering a courthouse where they planned to detain a Jamaican man
Turtle rescue season starts on Cape Cod beaches
The season's first cold-stunned sea turtles were rescued from Cape Cod beaches over the weekend
Police: Officer opened fire after being hit by dirt bike
Rhode Island officials say an environmental police officer fired his weapon after he was hit and injured by a man on a dirt bike
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Man who slashed 'Baby Trump' balloon during football game says he'd 'do it again'
Remember Watergate? Trump impeachment inquiry heads for live TV
GOP tries to change the subject, move impeachment inquiry away from Trump


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Australian cycling bosses believe Brian Cookson's election as head of the sport's world governing body can prompt a positive, global impact.
Cookson was elected president of the International Cycling Union (UCI) on Friday after beating embattled incumbent Pat McQuaid at the end of a protracted and chaotic election process.
It capped a long and frustrating day in Florence's Palazio Vecchio, where McQuaid, in power since 2005, had initially failed to gain nomination, but forced his way through by relying on loopholes in the UCI constitution.
In the end Cookson called McQuaid's bluff by calling for a quickfire vote and was rewarded by gaining 24 votes to McQuaid's 18.
A year after cycling suffered a hammer blow due to Lance Armstrong's spectacular fall from grace following a lifetime doping ban, the UCI still has damage to repair.
With plans to run the UCI differently, and hand anti-doping tasks to an independent body, Cookson is hopeful cycling can still reach its "enormous potential."
"I have said throughout my campaign that we must embrace a new style of governance and a collegiate way of working, so that a new era of growth and commercial success for the UCI and our sport can begin," the Englishman said.
"Ultimately that's how we are going to grow our sport worldwide and get fans into cycling," he added.
Leighton said Australia had been the first federation to publicly endorse Cookson because of the need for change.
While the Scots-born administrator does not expect a direct impact on the sport Down Under, he believes Cookson can be the "catalyst" that will pull the sport forward.
"We took the decision to come out and publicly support Brian Cookson's candidacy four weeks ago, because we felt he represented the change that was required," Leighton said on Friday.
"Rather than wait for a secret ballot, we started that trend," he added.
It was a protracted and at times dramatic election at Florence's Palazio Vecchio, where McQuaid fought tooth and nail to hang on to the job he took from predecessor Hein Verbruggen eight years ago.
Without endorsements from his home federation as well as Switzerland, where the UCI is based, McQuaid desperately tried to amend article 51.1 of the UCI constitution to allow him to be nominated by another federation.
However, when the vote was put to the 42 delegates, McQuaid missed out when a secret ballot returned a 21-21 draw.
Determined, the Irishman then presented two Swiss lawyers who said article 51.1 was open to interpretation, allowing him to be nominated by the Thai and Moroccan federations, and claiming the Swiss federation's previous withdrawal of his nomination had no legal standing in the country.
Cookson ultimately called the Irishman's bluff, a move he later admitted probably gave him the edge.
While Leighton played down the drama, he acknowledged McQuaid had been in a fight to the death.
"He was fighting for his skin, for his job. That's what Irishmen do," he said.
Turning to Cookson, the Australian added: "There was a vote and he won the vote. Now hopefully there will be some change for the better."
"There's a chance to create a better environment for cycling globally. It's not about one person. It's about an attitude. With any team, you have to have the will to develop and progress your objectives," Leighton said.
"I don't think it will have a massive effect on Australiana cycling ... but cycling is a global phenomenon and it requires constant development," he added.


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AMV Contest Rules for Anime Conji 2013
Best Drama - Ghost of a Rose by tipsd9videos
Best Action - Rise Up by Pikapwn
Best Comedy - Nothing on TV Anyway by Cumberpunch Studios
Best Upbeat - Till Then by GuntherAMVs
Judges' Choice - Evangelion 0.01 - Shinji is (Not) the Boss by l33tmeatwad
Best in Show - Nothing on TV Anyway by Cumberpunch Studios
The contest played on time and without a hitch, and we got to play the winners during the Masquerade half-time show. And the best part was our Best of Show winner was present to receive her awards:
Completely surprised her, too XD. we heard the shriek from the other side of the 2100 person sized room behind the screens when her video came up.
OH wait.... i'm missing something.... Oh right, I mentioned a custom award representing Coordinator's Choice (MY favorite, in other words.... ) here ya go!
Coordinator's Choice - Till Then by GuntherAMVs
Yes, I am the artist. The painting is roughly 9"x6", i'm too tired to try measuring it right now
Congratulations to all the winners! Unfortunately, we have no swag but we will be mailing out your awards asap.
Victoria Galietta
John Galietta III – Anime Conji AMV Events Assistant Coordinator


text:
Bought a lovingly used machine that came with the embroidery attachment, extra large hoop, extension tables, thread rack, an assortment of six artista embroidery cards, regular and embroidery shuttles and extra bobbins.
Am very pleased with with purchase... and excited about the potential. My question though is... am I restricted to the Bernina Artista software? Can I use other software (Embird for one) and connect to the 180?
I would greatly appreciate any input or suggestions.


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A Data Structure is simply a structure which holds data together. Data structures are very useful as they are used to store a collection of of related data.
Data Structures in Python
The built-in Data Structures in Python are as follows-
A list is an ordered collection of data items. Lists are used to group together some other values. A list can contain values of any type. The items of a list are enclosed within square brackets. Lists are mutable, whic means you can add, remove or search for items in a list. Here is how to create a simple list-
#a list of friends is created friends=[pervej,joy,arafat] print I have ,len(friends), friends. They are- for i in friends: print i #add a new friend to friend list friends.append(rakib) #delete an enty from friend list del friends[1] print My friend list is now,friends
I have 3 friends. They are-
My friend list is now [pervej,arafat,rakib]
The example above demonstrates how to create a list, add & delete item from it. To access an item from a list index numbers are used. Remember, Python starts counting items in a list from 0, means first item of a list is 0,not 1.
Note: The items of a list may be of any data type. Also a list can be nested into another list. Take a look at the following lists-
list1=[6,7,8] #list of integers list2=[6.3,9.0,6.1] #list of floating points list3=[mango,apple,banana] #list of strings list4=[python,12.7,25] #list of items of mixed data types list5=[apple,8,[atik,pervej]] #list within another list
Tuples are like lists except they are immutable, which means they cannt be modified. They are usually used in cases where the collection of items need not to be changed. The items of a tuple are seperated by comma and enclosed within a pair of parentheses.
Example:Using Tuples
#creating a tuple fruits=(mango,apple,orange) new_fruits=(banana,berry,fruits) print fruits[1] print new_fruits[0] print new_fruits[2][2]
Tuples with print statement
Sometimes it is useful to use tuple along with print statement. Here is how it is done-
name=atik age=20 print %s is %d years of age%(name,age) #here (name,age) is a tuple
atik is 20 years of age
Here tuple with print statement makes it possible to avoid the usage of commas and make easy to print output. What Python does here is that it converts each item in the tuple into a string and substitutes that string value into the place of the specification.
Another important built-in data type in Python is dictonary. Unlike lists and tuples, dictionaries are indexed by keys whereas lists and tuples are indexed by a range of numbers. Simply a dictionary is a mapping between a set of keys and a set of values.Each key maps to a value. The association of a key-value pair is called an item. The keys are immutable.
A dictionary is defined like this: d ={key1 : value1, key2 : value2 }. The key and value pairs in a dictionary is separated by a colon, and the pairs are separated themselves by commas and all this are enclosed in a pair of curly brackets.
Take a look at the example below how to create a dictionary, add , delete and search an item-
#creating a dictionary phone_book={atik:[email protected], pervej:[email protected], rakib:[email protected]} #add a new item phone_book[arafat]=[email protected] #delete an existing item del phone_book[rakib] for i,j in phone_book.items(): print Contact %s at %s%(i,j) #search for an item if phone_book.has_key(atik): print Atik is available at %s%%phone_book[atik]
Contact atik at [email protected]
Contact pervej at [email protected]
Contact arafat at [email protected]
Atik is available at [email protected]
Newer versions of python includes a new data type named set which supports mathematical operations like union, intersection, difference and symmetric difference. A set is simply an unodered collection of elements which permits no duplicated element. So, sets are usefull in membership testing and eliminating duplicate entries.
Creating set
Sets are created using the function set() or by using curly braces. Here is how to create set-
Example:Creating set
>>>users={atik,pervej,rakib,atik} >>>print (users) {atik,pervej,rakib}
Here we have created a simple set named users. As i mentioned earlier, a set never permits duplicated entries. So when we print the set, we get only the unique entries. Look at the print statement, which is not similar so far we have seen. This is because at newer version of python, print() is a function and you have to print anything like this.
Set operations
We have already known that set supports mathematical operations like union, intersection, difference and symmetric difference. The following example demonstrates the mathematical operations of set-
Example:Mathematical operations of set
>>>a=set(abdame) >>>b=set(amtda) >>>a {a,b,d,m,e} >>>b {a,m,t,d} #difference of a & b >>>a b {b,e} #union of a & b >>>a | b {a,b,d,m,e,t} #intersection of a & b >>>a & b {a,m,d}
List, tuples and strings are example of sequences. There are two main features of sequence-
1.Indexing operation
2.Slicing operation
Indexing operation allows us to fetch a particular item in the sequence while slicing operation is useful to retrieve a slice of the sequence. The following example demonstrates these operations-
Example:Sequence operations
friends=[joy,rahat,rony,pervej] #indexing print friends[0] print friends[1] print friends[2] print friends[3] print friends[-2] #slicing using a list print friends[1:-2] print friends[:] #slicing using a string name=atik print name[0:1] print name[1:4]


text: Laura dreams the dream of living like a craft-star pop diva. Striving to become an artisan whose art is the "day job." Knowing that in an alternate dimension this is the case, she does the behind the scenes work in this reality to create the cool items, that score her diva status over there, in that alternative place.


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Cedrus Hidalgo sweeps titles in Mexican League
Mexico City, Mexico, March 15, 2014 - IMSS Cedrus of Hidalgo captured the title in both genders at the inaugural Mexican Volleyball League.
The Final Four event took place at Juan de la Barrera Olympic Gymnasium in Mexico City in front of thousands spectators.
In the men's division gold medal match, Cedrus edged Nuevo Leon University 3-2 (25-21, 21-25, 20-25, 25-22, 15-10) and claimed a 3-0 (25-18, 25-11, 25-13) victory over Chihuahua in the women's final match.
Mexico City Hawks prevailed in a tough five-set battle (25-23, 21-25, 25-20, 24-26, 15-6) with Colima to take the men's bronze medal. The women's third place went to Colima with a straight-set (25-19, 31-29, 25-21) victory over Nuevo Leon.
Jesus Valdes Loredo of Nuevo Leon and Seomara Sainz of Colima won the Most Valuable Player honors.
The awards were presented by Jesus Perales, President of the Mexican Volleyball Federation, during a colorful closing ceremony.
Men's Individual Awards
Best Setter: Oscar Aguirre
Best Middle Blocker: David Alva
Best Opposite: Nestor Orellana
Best Receiver: Jair Morales
Best Libero: Jesus Rangel
MVP: Jesus Valdes
Women's individual awards
Best Setter: Rosa Vallejo
Best Middle Blocker: Carolina Carranza
Best Opposite: Andrea Rangel
Best Receiver: Alejandra Isiordia
Best Libero: Kaomi Solis
MVP: Seomara Sainz


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I always get a little uneasy that all the theories I can think of (at least since Newton) are constructed in a way such that they would be true in heaven and on earth ... but we can never go everywhere and test it out.
So here is the question:
Is there some good justification to implement something like the principle of relativity in scientific theories other than it turned out to work good so far?
Some more motivation:
We have an understanding of different places in space (and time) and what different velocities are. Like imagine me and my droogs cruising our skateboards down the neighborhood and there is a truck driving in the other direction. I see a cactus on the roadside and I wonder how the trucker in his ride sees it.
Now in the maths, space $\vec x$ and spacetime $t$ represent physical space and physical time. And if I know my coordinates, the form of the plant and its location and orientation in space, I can find out what I see and also what the trucker from his position sees. A coordinate transformation (replacing some letter on a piece of paper with some other letters in a systematic way) is conventually interpreted as taking the data from one "perspective" and transforming it into "another perspecitive".
It's supposed to be a fruitful approach to physics to consider only the observable quantities. Maybe I interpret the principle of relativity the wrong way, but I find it funny that a theory tells me there are spacetime events where I can never get to (outside the light cone). And simultaneously I'm guaranteed that if I'm there I would also be able to physics and come to the right conclusions. At the very least, I feel this is somewhat redundant - why not drop it?


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Realtek ALC650/ALC655 AC97 Audio A3.52 driver download
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text:
Thyroid nodules are growths in the thyroid, a gland in the front of your neck. Most of them are harmless.
All or part of the thyroid gland may be removed if a nodule is cancer or if it causes problems with breathing or swallowing.
Last Revised:
September 27, 2012
Healthwise Staff
Medical Review:
E. Gregory Thompson, MD - Internal Medicine & Matthew I. Kim, MD - Endocrinology
This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.
To learn more visit Healthwise.org
© 1995-2012 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.


text:
Motion in the Cash Cycle
From banknote design, through printing, to processing: today's key topics in relation to the money cycle.
Cash is always in motion. Certified printing plants deliver banknotes to central banks. Cash-in-transit companies pick up the notes from there. The cash then reaches companies and – through ATMs – private households. Individuals and companies then deposit the money back into the bank, which retains some of the cash in order to fill up its ATMs. Any cash that is not required is returned to the central bank by the relevant financial institution. In some countries, companies also deposit cash directly with the central bank.
Systems and processes that fulfill the highest security requirements guarantee this smooth and efficient cash cycle. This is the only way to ensure that banknotes also continue to enjoy peoples' trust.
G+D Currency Technology accompanies the entire cash lifecycle and supports the market and its customers in an ever-faster money cycle; follow current trends and let yourself be surprised and impressed by our innovative solutions
Cash Center of the Future
What direction should the development of the cash center take if it is to survive in a dynamic, digital environment that is constantly changing? It needs to become an intelligent, secure, and efficient hub that informs the entire currency cycle and designs it to be future-ready.
Dividing up the Cash Cycle Cake
An increasing number of central banks are transferring elements of their work to cash-in-transit companies, commercial banks and other commercial players with the objective of making cash management more efficient. But can this happen without losing control over the process?
A new Era in Egypt's Cash Cycle
In Egypt, Giesecke+Devrient designs and builds an integrated plant for the production and processing of banknotes. A starting point for a new era in the countrys cash cycle.
Secure Network Communication for Cash Processing Systems
Cash processing solutions have become digitally connected on a huge scale, both within companies' internal IT networks and via web- and cloud-based solutions. This development has brought advantages in terms of speed, transparency, and cost, but also entails high security risks.
The Cash Question: Currency Management for Central Banks
Central banks are facing new pressures. Therefore, many are redefining their role in the cash cycle.
More Business Power for the Cash Cycle
The most important trends and developments associated with the cash cycle were discussed at the "Currency Technology 2017" symposium in Munich.
Innovative Systems for Commercial Applications
This September, the Giesecke+Devrient Currency Technology GmbH product range is expanding to include two new banknote processing systems: the compact table-top device BPS® C2 and the modular high-speed system BPS® M3.


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Fire-retardant tape suits maintenance and wire harness applications
For wire harness and electrical maintenance applications that require fire retardancy, Scapa 165 is a black cotton cloth tape single-coated with a natural rubber pressure-sensitive adhesive. The tape bonds to most surfaces and is highly abrasion resistant. Designed for heat-generating appliances, the tape works best as a fire-retardant primary wrap for wire harnesses. Scapa North America
Circle 246 on Reader Service Card
Hole saw has variable pitch tooth pattern
This bimetal hole saw includes a ¾ variable pitch tooth pattern said to cut 20% faster, improving contractor productivity. This ¾ variable pitch also provides a fast, clean cut that does not sacrifice the quality of the materials being cut, whether metal, wood or composite. The bimetal hole-saw teeth are designed with M42 tool steel reducing premature saw replacement. Greenlee Textron
Circle 275 on Reader Service Card
Multipole connector ensures greater conductivity
The SB 175 multipole connector is said to ensure greater conductivity and longer life. The connector features spring-loaded, silver-plated contacts that create a self-wiping action during mating and unmating. This design resists arcing by keeping the conductive surfaces clean and free of corrosion. The product is available in a standard array of colors that follow the industry-wide color code for voltage identification. Anderson Power Products
Circle 249 on Reader Service Card
Cable fasteners tie quickly
These Velcro Qwik Ties, part of the One Wrap family of fasteners, are designed for commercial bundling and cable management applications. This self-engaging fastener attaches to itself by using hook-and-loop technology to create a restraining device that fastens without twisting, tying or adhering. The ties are easy to apply and will not over-cinch cables. Velcro USA Inc.
Circle 248 on Reader Service Card
Switchboard-case retrofit option reduces installation costs and simplifies upgrades
This switchboard-case retrofit option, designed for the manufacturer's ION 7300, ION 7330 and ION 7350 power meters, allows the meters to come pre-wired within a sturdy metal frame, complete with a control panel and LCD display mounted in its removable front cover. Installation is then a matter of plugging the device into an existing GE S-1 or ABB FT-21 switchboard case. Best for replacing older metering devices, this option makes it quick and easy to install or remove a meter. A quick-disconnect system allows the user to remove or "draw out" the meter electronics in one easy action, without having to manually disconnect any wiring. Power Measurement
Circle 273 on Reader Service Card
Handheld oscilloscope now comes in full-color on larger screens
Two full-color instruments have been added to the ScopeMeter 190 Series handheld oscilloscope product line. The 196C and 199C scopes provide full-color display capabilities on larger screens, faster display update rates and additional capabilities. The color and display speed of the scopes make identification of individual waveforms significantly easier, allowing the user to visually distinguish individual traces if waveforms are displayed on top of or close to one another. The bright color display of the 196C and 199C, higher screen resolution (now 320 × 240 pixels) and a deeper memory (1,200 instead of 1,000 samples in scope mode, or 27,500 samples in ScopeRecord mode) further enhance the detail reproduced on screen. Fluke Corp.
Circle 276 on Reader Service Card