Quality Definition and 205 Threads

I currently have a warning for poor quality posts or what mods call 'substandard' posts. I'm not trying to argue with the mods or appeal anything here in the post.But rather I wish to know what kind of posts the mods accept. I understand the need for PF to be heavily moderated to keep crackpots...

22/7 is a very good approximation for π. Sqrt(2) doesn’t do that well until 99/70 and e doesn’t do that well until 193/71. 355/113 is even better. Is there some reason for this? Perhaps geometrical? Why do the ratios of small integers work better for π than other numbers? Or is it just...

It seems to me though WAV files are heavier than the others in bytes it has the best sound quality. It's interesting since nowadays you can download more quickly (who knows perhaps this is also a lie... :cool: ) files, so why bother for MP3 or FLAC, the good old WAV file is da best! Unless of...

I'm trying to find the quality factor of a damped system. I know 3 points from the graph, ##(t,x): (\frac{\pi}{120},0.5), (\frac{\pi}{80},0), (\frac{\pi}{16},0)## From this I found that ##T = \frac{\pi}{20}## ##\omega_d = \frac{2\pi}{T} = 40 rad## Then, from the solution ##x(t) = A_0...

Hi all., Just hoping to get a better fundamental insight into a few things. If we start with this: http://hyperphysics.phy-astr.gsu.edu/hbase/Kinetic/vappre.html so we have a closed container at a given temperature, then we can find it's saturation pressure. All good so far. In the following...

The oscillator's initial energy can be found by considering when all of its energy is potential energy. Eo = (1/2)kA2 = (1/2)mω2A2 = (1/2)me(2πν)2A2 = 2meπ2ν2A2 where me is the mass of an electron. With this in mind, the energy dissipated after one cycle is given by ΔE = E(0) - E(1/ν) = Eo -...

Hello. Questions: What should be the quality of research papers or research works and results in math or physics? I have this wrong idea that it should be equivalent or better to that of Einstein's but i think on the other hand it should not be but i do not know, i have my doubts. So should...

Is anyone familiar with the books printed by CRC Press? Not the actual content of the book, but the materials used for the hardcover books. Ie., do they fall apart like Springer's books printed today? Or are they made with better binding.

HI! Can you rate the book i mentioned below in terms of quality of concepts and the problems given. What do you think about the difficulty of the book?(For a moderately beginner person). Thanks! The link is .. [Moderator's note: link removed].

Hi, doing some research for free Latex editors for Windows 10. I did an online search but would like to know the experiences of people with Latex editors, if any. Thanks.

Which do you think is superior, given similar tech for both opponents? If one opponent nation went all in for mass produced cheap space vehicles, would that not beat one that produced a limited number of heavily armed spacecraft ? Scenario is a space battle only, from deep interplanetary...

some ideas so far: ozone generator, soap and water rinse, ammonia based cleaning solution, keep airing out maybe with a fan (but rather not risk any sparks and such either) Ideally I don’t want to have to try a dozen things, so I’ll see what ppl support the most. Thanks science ppl!

Hi PF! I have a 3D surface that changes with time. I am trying to make a movie. The following is what I do, but the output is extremely low quality. Does anyone know how I can get the same quality that Mathematica uses for its images? mov[t_] := Show[ParametricPlot3D[{(2 + Cos[v]) Cos[U]...

Hi! I was wondering if you can suggest any decent DC-DC step-up converter that would actually withstand 100W output? My intention is to convert 12V to 23-24V and feed it to 100W consumer. I got myself 150W step-up module that according to specs should withstand 150W or 6 Amp at output (when you...

There is an original image test1.jpg. The problem is to show axes in the image and retain image quality. I am running the following code: img = imread('test1.jpg'); % define variables imgsize1 = size(img,1); % size on screen imgsize2 = size(img,2); xreal = 1; % meter yreal = 1; %...

I am currently applying to physics graduate programs (considering both Master's and Ph.D.) in both Europe and North America. In choosing programs, I really care about teaching quality: emphasis on pedagogy, well-designed syllabi, and professors who are passionate about teaching. The QS World...

Hi all! Not sure if this is the right place but I am having really hard time getting these questions answered in other places as well. I became interested in EM topic when power company decided to build a 2x110kV power line near my house. I would like to approach this problem rationally with...

I have collected velocity data for a 3-D grid of test section of a low speed wind tunnel.I have tested airfoils for pressure distribution in the same test section for similar free stream conditions. How do I calculate the impact of flow quality in the test section on the test results of pressure...

Homework Statement Explain the effect expected on the quality of imaging if an X-ray fluoroscope system is adjusted so that it: a) uses higher kilo voltage b) reduces the dose-rate to the detector and c) delivers radiation in pluse rather than continuously Homework EquationsThe Attempt at a...

Hi All, Currently on a distance learning HNC and I am not quite sure whether the question just wants me to answer 'yes' or give mathematical evidence. Part A answered, Part B not sure... Any help would be great! 2. The process for the production of an electrical device is suitable for...

I'm finishing up my first semester of college this month and looking ahead for long term planning and I'm in need of a little insight. This was my first semester and I took 6 classes (all entry level generals like basic Chemistry, Psychology, History, etc) and worked pretty hard to get A's in...

What is the Sun ray brightness quality after mirror reflection and what affects it? How to get the efficiency after reflection?

Homework Statement Each day a quality engineer selects a random sample of 60 power supplies from the day's production, measures their output voltages, and computes a 90% confidence interval for the mean output voltage of all the power supplies manufactured that day. What is the probability...

Hello all, It's known that the Quality factor Q is defined as : Q = 2*pi*(Energy stored at resonance) / (Energy loss per cycle) and for high Q resonators, It's known that Q can be also given by : Q = Resonance frequency / 3dB Bandwidth My question is, How can i prove that ? that both...

I purchased a 6" mirror reflector telescope, but no matter how much I tried to get good photos all came out blurry, I'm guessing the mirror was low quality, also the tracking system made absolutely no sense and could not even find the Moon. Not just that but it wasn't stable either. So...

Lil background that may support the best answer to my question. I'm a plant manager for a small landfill gas power generation facility 3.6MW, 2ea RICE CAT 3520'S, which are paralleled to the grid. I believe my site is experiencing utility power quality issues that are effecting genset...

I'm currently in the 5th week of the 9-week Coursera course on first-level math logic, "Introduction to Mathematical Thinking," created by Keith Devlin of Stanford. I'm an older adult doing self-study, in hopes of brushing up my high school math & adding the other necessary math skills to...

Homework Statement Suppose you want to use a series RLC circuit to tune in your favorite AM radio station which broadcasts at a frequency of 1.20 MHz. You would like to avoid the obnoxious easy listening station which broadcasts at 1.10 MHz, right next to the one you like. In order to achieve...

Hello I have to conduct factory inspections of Polyethylene pipe / fittings manufacturers on behalf of my company. The PE products are to be used in natural gas pipeline network. In order to check conformance to relevant standards / best practices, I have prepared a set of questions to ask...

I'd like to test the quality and performance of an electrical item I intend to sell. I was able to find a similar, very high quality product whose quality I'd like analyzed and compared to lower quality alternative. Who should I send these two product samples to? A third party inspection...

I'm in a dilemma right now. I've a mechanical engineering degree, and I wanted to supplement it with something before I join the work force, so I applied to two programs, Quality engineering post grad diploma, and a Non-Destructive testing technician diploma. Which one do you think has better...

Problem: Suppose I have a production process that yields output in batches of n items. For each batch, I can test whether they are of good or bad quality. Let q_i ∈ {1,0} be the quality of tested item i. If more than half of the items are ‘bad’, the batch should be discarded. In other words...

I'm currently writing a paper on the Multiverse. I do have a theory of my own and have made the outline and started working on it. However, the language seems to unscientific, in the sense, its not very objective and crisp. How do i improve the quality of language and content of the paper. Any...

Hi Anyone got any suggestions/recommendations for literature either available for free online or books that I have to buy? My background: Electrical engineering student, working on a project that is about analysis of power quality with focus on harmonics.

svein submitted a new PF Insights post Reflections on Product Quality Continue reading the Original PF Insights Post.

Hello guys. can you tell me what is a Quality Life? I have been searching this for the past few weeks but all the information i get is about "Quality of Life" and it is not the data i wanted to get :(

Just curious if anyone here has worked in quality engineering before and could share their experiences (manufacturing, maybe software quality assurance)? Not really looking for guidance here, although I work as a quality tech and plan on going for a degree in physics (I know I should probably...

What is the effect of on-grid PV systems, in terms of quality, voltage and stability? I'm not really sure how to answer this. Stability -- If consumer is tied to a PV power plant, grid stability could potentially be an issue. However, generally speaking, on-grid systems use the grid like a...

Perhaps someone here can help me. I have looked at many day cares and preschools here in Sunnyvale, California and the air quality is poor. Many house 12 to 20 kids (whose respiration is effectively similar to adults) and 2 teachers in a room that is small enough that if it were a workplace...

For the quality, or timbre, of sound, multiple harmonics are present. How is that possible for a string or a tube? Are there any good pictures of how a wave on a string has multiple harmonics present at the same time? Thanks.

What is that one thing(maybe many) about you that is very extraordinary and makes you feel proud about yourself ?

I know that the Millennium Edition of FLP is supposed to be the most up-to-date and corrected, however, I have read (in amazon) really less than ideal reviews on how glossy the pages are, how light the printed text are, and how the texts go inside the left margin making it very difficult to...

Having graduated from university 4 years ago (B.S. Aeronautical Engineering) and currently working in industry for the last 2 years, I've noticed a startling number of engineering graduates who don't have basic skills one would think an engineering graduate would have acquired during their...

Homework Statement Light with wavelength 500 nm is emitted from an electron in an atom behaving as a lightly damped simple harmonic oscillator with Q = 5 x 10^7. Find the linewidth (width to half-power points) in nm. Homework Equations wavelength=c/f f=w/2pi Q=f/delta f=w/delta w The Attempt...

So every time I do some research on the internet I run into major problems... like some freaky stuff, and this isn't QM freaky... its just freaky. Anyway while roaming google as ome does I come across a scientific article that is so well writted it had me convinced, it even had another article...

I'm a first year electrical engineering student and I had a lecture on Analogue and power electronics today. The main topic the lecturer was talking about was headphones and stereo systems etc. We learned about frequency responses and looked at product specifications and circuit analysis and...

I don't know if it is a correct sub-forum to ask but I have doubts. In STEM, developing countries do need quality professors or skilled persons. This leads to innovation and start of service-oriented sectors. This leads to improved quality of life for all these people. Now my question is, what...

It's a very simple question but still, When two identical guitars are played day two persons to give notes of the same pitch, will they differ in quality? Please specify with reason. Thanks for the replies.

I have noticed that the quality of books by these two publishers has plunged. I have seen a couple of recent Springer titles with very poor glued bindings and very poor print quality. What Elsevier-Butterworth-Heinemann have done to the Landau and Lifshitz series is criminal. The Pergamon...

Homework Statement S = a non-empty set of vecotrs in V S' = set of all vectors in V which are orthogonal to every vector in S Show S' = subspace of V Homework Equations Subspace requirements. 1. 0 vector is there 2. Closure under addition 3. Closure under scalar multiplication The Attempt at...