What is a good textbook for second year fluid mechanics (materials engineering/science)?  Currently, I am using Gaskell, "An Introduction to Transport Phenomena in Materials Engineering".   Thanks
I have my bachelors degree in engineering science: computer science, option electrotechnic. I have a good understanding of basic mechanics and dynamics, calculus (differential equations).  The books I'm now having a look at are:       What book do you recommend for studying fluid dynamics on my own and why?
How does accepting an answer work? What does it mean to accept an answer? How do I accept an answer, and what are the rules? Can I accept my own self-answer? What are the reputation benefits? Which answer should I accept? Should I upvote the accepted answer? What should I do if none of the answers are suitable?      For more information, see "" in the . According to the documentation  in order to retrieve a list of picklist values for an object we need to pass in a Record Type Id which can be retrieved using the getObjectInfo method.   The issue is that these are both wire functions and I cannot figure out how to chain these methods.  If I try code like the following:  getObjectInfo({ objectApiName: ACCOUNT_OBJECT })             .then(result =&gt; {                 return getPicklistValues({recordTypeId: result.defaultRecordTypeId, fieldApiName: TYPE_FIELD});             })             .then(result =&gt; {                 this.picklistValues = result.data             })             .catch(error =&gt; {                 this.error = error;             });   I get an error      render threw an error in 'c:getpicklistexample' [Imperative use is not   supported. Use @wire(getObjectInfo).]   If I try something like   @track rtId;      @wire(getObjectInfo, { objectApiName: ACCOUNT_OBJECT })     handleResult({error, data}) {         if(data) {             this.rtId = data.defaultRecordTypeId;         }     }      @wire(getPicklistValues, {recordTypeId: this.rtId,fieldApiName: TYPE_FIELD})     picklistValues;   Then it throws an internal server error. Anybody have an idea as to how I could retrieve the record type Id and then call to get the pick list values like the documentation suggests?  FYI my imports are:  import { LightningElement, wire, track } from 'lwc'; import { getPicklistValues, getObjectInfo } from 'lightning/uiObjectInfoApi'; import TYPE_FIELD from '@salesforce/schema/Account.Type'; import ACCOUNT_OBJECT from '@salesforce/schema/Account'; Remove all files/directories except for one file I have a directory containing a large number of files. I want to delete all files except for file.txt . How do I do this?  There are too many files to remove the unwanted ones individually and their names are too diverse to use * to remove them all except this one file.  Someone suggested using   rm !(file.txt)   But it doesn't work. It returns:  Badly placed ()'s    My OS is Scientific Linux 6.  Any ideas? "have" vs."have got" in American and British English I have looked through several questions and answers on EL&amp;U, and often there is an indication that American English prefers "have" while British English prefers "have got". In addition, there are several references to "have got" being more informal than "have" (e.g.: , ). But where is it considered more informal? In American English alone or both American and British English?   This point may seem obvious to those who made the above mentioned references, but the fact is that even the most fluent users of English in my country will say without a doubt that 'have got' is the preferred usage in the UK and, therefore, it must also be more formal. Why? Because in an academic environment, the more informal structures are generally frowned upon, outside some specific spoken exercises. And if the teachers insist on using "have got", it follows it isn't informal.  So, is the teaching of (British) English in our schools transmitting the wrong idea?  EDIT: I'm adding some information in answer to the comments.  I'm mainly concerned with the idea of possession:      I have got a cat vs. I have a cat and She has got a dog vs. She has a dog   As mentioned in the comments, every (Portuguese) student will be told that "have" and "have got", when it comes to the idea of possession, are absolute synonyms, the only two differences being:    "have got" is preferred by British English, "have" is preferred by American English   the negative and interrogative structures differ    I have never heard of any distinction in formality. In fact, I was rather surprised when I went through the EL&amp;U archives and read about it.  So, would "I have got a cat" be as formal/informal as "I have a cat"?   And how do British and American English look at its formality/informality? Is it the same? Drawing a constant randomly distorted circle I am trying to draw a special and contradictive plot : A circle with random distortions which have to remain constant regardless of how many times I build the document.  An example of what I am trying to achieve can be seen below    This figure was produced with the following code  \documentclass{standalone} \usepackage{tikz}    \usetikzlibrary{decorations.pathmorphing}   \begin{document}     \begin{tikzpicture}         % axes         \draw[ultra thin] (-2.5, 0) -- (2.5, 0);         \draw[ultra thin] (0, -2.5) -- (0, 2.5);         % undistorted sphere         \draw[ultra thin, dashed] (0, 0) circle (2.25cm);         \draw[ultra thin, dashed, -&gt;] (0:0) -- (125:2.25);         \node at (-1, 1) {$R$};         % distrorted sphere         \draw[very thick] plot[domain=0:350,smooth cycle ] (\x:2+rnd*0.5);         \draw[very thick, -&gt;] (0:0) -- (45:2.1);         \draw[ultra thin, -&gt;] (1, 0) arc (0:45:1);         \node at (1.2, 0.4) {$\theta$};         \node at (0.7, 1.25) {$R(\theta)$};     \end{tikzpicture} \end{document}   The problem with the code is that whenever I make a change to it and rebuild the document, the "distorted" circle will have a different shape, since I am using the rnd function. The reason I would like to have a constant-random shape is because I would like to denote its radius at an angle θ, therefore it has to touch the outline of the circle.  Any idea on how to achieve such a thing? How do you decline nouns borrowed from languages with several categories for declining nouns (or none at all)? When & How often do 4e Monster powers recharge? I recently upgraded from blender 2.81 to 2.82a, and I've immediately noticed a problem. Blender is not rendering HDRI images like it used to. You used to be able to plug an HDRI image into the background node, and into the world output. However when I do this now, in Eevee or Cycles, it renders what can be described as "as solid color" version of the HDRI instead of the actual HDRI image.   Here are some images to show as examples, each has a difernt HDRI, one is in Eevee, one is in Cycles. Is this a new "feature" of 2.82 or is this a bug? Thanks. Linked and Related sections contain duplicate links to questions Is the cube root of a prime number rational? The question is: if $P$ is prime, is $P^{1/3}$ rational?   I have been able to prove that if $P$ is prime then the square root of $P$ isn't rational (by contradiction) how would I go about the cube root? Test model coefficient (regression slope) against some value In R, when I have a (generalized) linear model (lm, glm, gls, glmm, ...), how can I test the coefficient (regression slope) against any other value than 0? In the summary of the model, t-test results of the coefficient are automatically reported, but only for comparison with 0. I want to compare it with another value.  I know I can use a trick with reparametrizing y ~ x as y - T*x ~ x, where T is the tested value, and run this reparametrized model, but I seek simpler solution, that would possibly work on the original model. This comes from a brain teaser but I'm not sure I can solve it:     You are in a rowing boat on a lake. A large heavy rock is also in the boat. You heave the rock overboard. It sinks to the bottom of the lake. What happens to the water level in the lake? Does it rise, fall or stay the same?   I'd say that the water level drops, because when you drop the stone in the lake, the water level rises according to the volume of the stone, BUT the water level decreases by a volume of water weighting the stone's weight, when you take it off the boat.  Is that correct? How to model this odd-shaped distribution (almost a reverse-J) My dependent variable shown below doesn't fit any stock distribution that I know of.  Linear regression produces somewhat non-normal, right-skewed residuals that relate to predicted Y in an odd way (2nd plot).  Any suggestions for transformations or other ways to obtain most valid results and best predictive accuracy?  If possible I'd like to avoid clumsy categorizing into, say, 5 values (e.g., 0, lo%, med%, hi%, 1). What do you call somebody who asks a question and somebody who answers a question? Do elevator upgrades increase your passive credit earnings, too? QGIS 3.4 : Add points to exact locations? I would like to add several coordinates at specific British National Grid Easting and Northing values. I know this can be done by bringing in a .csv, but I want to know is there a way to manually enter the numbers in QGIS 3.4, and then the point moves to that location ? I've read that in QGIS 2.x there was a plugin called Numerical Vertex Editor that doesn't seem to exist for 3.x ? I use a cookieless sub domain static.example.com to serve all images, js, and css files. This static sub domain has as its root directory the same directory as the parent http://example.com. So static.example.com/index.php will result in calling the same file as http://example.com/index.php  Google has taken up indexing static.example.com and I need to stop this.  I can't modify robots.txt since it would apply to both domains. Webmaster tools allows "temporary" removal of a link, but this needs to be permanent.  I registered this static domain through google as a separate site from example.com, but this doesn't seem to buy me anything since I can't see a way to block crawling without using robots.txt - which would block it from the parent domain.  Any other ideas?  UPDATE  Found this conversation on   I am looking into whether it's possible to insert a META tag dynamically into the header of every page called on the static domain using php  CLARIFICATION  I am not putting any content on static.domain.com. There are NO webpages on it that are called - it only serves images. I have it redirecting to the same root directory as the main site for ease of coding image links (not every image is fed from the same image path).  Google got a hold of the static web root address - probably because .htaccess redirects to index.php if a file is missing and then crawled it. Now Google is showing the static version of the same pages with search results. How can I create an AddIn to ArcGIS Pro and where can I find it from ArcGIS Pro application? I have an unusual problem with Chrome when I try to open PDFs. If I have already downloaded a PDF and try to download it again, I can open it by tapping its name; in the screenshot below, I could tap "pdf.pdf" to open the file.   The issue is that tapping this link actually opens RollerCoaster Tycoon Classic! If I choose to download again, Chrome redownloads and opens the PDF correctly, so it's not a huge issue, but still an inconvenience.  In Settings, it says that RollerCoaster Tycoon Classic has no defaults, and I am unable to change the "open supported links" setting.    How do I stop RollerCoaster Tycoon  trying to be a PDF reader? Let $X$ be any distribution with defined mean, $\mu$, and standard deviation, $\sigma$.  The central limit theorem says that  $$ \sqrt{n}\frac{\bar{X} - \mu}{\sigma}  $$ converges in distribution to a standard normal distribution.  If we replace $\sigma$ by the sample standard deviation $S$, is there a theorem stating that  $$ \sqrt{n}\frac{\bar{X} - \mu}{S}  $$ converges in distribution to a t-distribution?  Since for large $n$ a t-distribution approaches a normal, the theorem, if it exists, may state that the limit is a standard normal distribution.  Hence, it would seem to me that t-distributions are not very useful - that they are useful only when $X$ is roughly a normal.  Is this the case?    If it is possible, would you indicate references that containing a proof of this CLT when $\sigma$ is replace by $S$?  Such a reference could preferably use measure theory concepts.  But anything would be great to me at this point.