Comparison Definition and 393 Threads

I want to do a study comparation of PMSM and BLDC Motor. I want to analyze the cost efficiency if BLDC were subtitute to PMSM. Where should i start? what kind of data that i need?

We have a question where we're testing the hypothesis that a certain diet (call it diet A) causes weight loss. We get ##n_1## people who we put on diet A (treatment group) and another ##n_2## people who we keep on a normal diet (control group). We find that the mean weight loss in the treatment...

I believe the z-score tells us Cindy did better in her test than Bobby. I also computed the following: Boys, on average, score better than girls.

Hi I just want to know the difference between Griv-Ex and G10. How long can they last and what speed up the degradation? eg UV, heat etc. thanks

Hello, this is my attempt for #19 for 11.6 of Stewart's “Multivariable Calculus”. The question is to determine whether the series is absolutely convergent, conditionally convergent, or divergent. The answer solutions used a ratio test to reach the same conclusion but I used the comparison test...

Hello I plotted the Parton distribution functions in Mathematica. Now I want to compare the graphs drawn with the graphs of other groups(xu and xd). How should I do this?

Hello All I have a reference in a 1930s journal to potassium bichromate. Is this the same as potassium dichromate K2Cr2O7 ? ie dichromate is the modern terminaology to use. Searching on the www almost always finds the dichromate when I search for the bichromate, but maybe this is just the...

I don't think it is possible, but can someone please explain why? Many thanks!

Hi, I understand there is computational research as well as completely theoretical research compared to experimental research. I was curious about what they are like. Could anyone point out some good papers? Thanks.

https://arxiv.org/pdf/1709.02481.pdf "Calculations have shown that field selfinteraction increases the binding of matter inside massive systems, which may account for galaxy and cluster dynamics without invoking dark matter. In turn, energy conservation dictates that the increased binding must...

On the test, I said they hit the ground simultaneously. However, that, in retrospect, doesn't seem to be the correct solution.

Hi, Has anyone experience with photovoltaic solar panels and thermal radiator type solar panels? 1/ How do they compare when both have the same collection area? If the thermal radiator was much smaller than the collection area, and a lens the size of the collection area was used, focused on...

Hello I'm trying to get some good reference material so I can do a literature review on Turboprops and a comparison of PSFC of Hydrogen/Methanol/Jet A1 fuels for turboprops. If anyone knows any good source material for this please let me know as I have struggled to find anything. Regards, Michael

Images comparison What are the best softwares available for comparing two images having similarity and differences? Two photos each of Margaret and Enid. 1 Margaret's first photo with her second photo comparison. 2 Enid's first photo with her second photo comparision. 3 Margaret's first...

Attempt: Note we must have that ## f>0 ## and ## g>0 ## from some place or ## f<0 ## and ## g<0 ## from some place or ## g ,f ## have the same sign in ## [ 1, +\infty) ##. Otherwise, we'd have that there are infinitely many ##x's ## where ##g,f ## differ and sign so we can chose a...

The answer sheet states that the series converges by limit comparison test (the second way). In the case of this particular problem, would it be also okay to use the comparison test, as shown above? (The first way) Thank you!

Let's say you know you are given the full genome of 2 individuals such that they are related as father/son or mother/daughter, that they both died at age 30 some 100 k years ago. Can you tell who is the parent/child by looking at their genomes only? If so, how? I picked 100 k years only because...

According to the Vaporization Heat table, the heat needed for 1 mol of H2O to evaporate at 100°C is 40.7KJ and 44.0KJ/mol is needed to evaporate H2O at 25°C. Thus 44.0-40.7=3.7KJ is the energy needed to heat H2O to 100°C from 25°C. However, according to the heat capacity of H2O, 3.7KJ will only...

Upon seeing the question in my assignment I knew in a isobaric process, work done by the gas is ##W=P\Delta V## so if volume is increased ##4## times the original considering the original volume as ##V## we can say after expansion the volume is ##4V##. Then ##W=P(4V-V)=3PV## and the ##Q## would...

Hello, All measurement instruments have a finite accuracy. For example, a thermometer may provide a temperature measurement that is +-2F from the "actual" and true temp value. For example, if the reported measurement is 70F, the actual temperature may be between 72F and 68F. That said, let's...

Let's say a small object orbits around massive object at some distance in perfectly circular orbit. In Newtonian physics the force acted upon orbiting body is: Force = m1 * orbital_speed^2 / distance = G * (m1*m2) / r^2 for an object of 1kg orbiting a body of 2*30^kg at the distance of 1.521 *...

Hi hi, here a question, how can we prepare Potassium sodium tartrate?, well, there is a lot of sites and videos, but in order to this right I'll write what have I done and checked, I'll try use the info I have, even if is not very dependable. First, we need sodium carbonate, to do this, we can...

Here's a nice video which is a size comparion of a great number of fictional structures from science fiction novels, movies and games. The video is called "FICTIONAL STARSHIPS Size COMPARISON" but it includes some structures I personally wouldn't call starships, but anyway... Enjoy...

The correct answer is the second one. I honestly have no idea why this is so. I understand that the right rope has less tension that the left one since it's at a shallower angle from real world experience, but I don't really know why this is so, let alone how the forces compare to gravitational...

Consider the following experiment: from a lacquered copper wire we cut off twenty to thirty pieces of about 10 cm. From them we form a bundle of parallel wires and connect the two ends with one more wire each. The other ends of these two wires are connected to a sensitive analog ammeter. We hold...

As the summary says: I have 2 induction heaters which are exhibiting different results when heating the same product. The 2 are different, having different sized coils, and I would like to work out the strength of the induced field in each of them (with a common item being heated) to establish...

We know that the momentum for such a lagrangian is: $$p_k = \frac{\partial L}{\partial \dot q^k} = 1/2 \Big( G_{ab} \delta_k^a \dot q^b + G_{ab} \delta_k^b \dot q^a\Big) = 1/2 \Big( G_{kb} \dot q^b + G_{ak} \dot q^a\Big) = G_{ak} \dot q^a$$ OK so using Hamilton's equation we get (and recalling...

I am trying to understand the difference between an Si IGBT and SiC MOSFET. The device structure in question is the following: https://www.researchgate.net/figure/Comparison-between-Si-IGBT-and-SiC-MOSFET-modules-a-Cross-section-of-Trench-FS-Si-IGBT_fig6_318908365 It's hard to understand why...

This question says: An HA weak acid solution with a molarity of 0.1M is dissolved in water. In the new solution, is the molarity of OH- greater than the H3O+ molarity, or the opposite? Or are they equal? I came up with two possible answers: 1. [H3O+]>[OH-] because there are no hydroxides...

Dear users, The situation I have encountered is a simple statistical comparison of the experimental data, which accepted as correct, with the results obtained via six theoretical models. In the experimental data, there exist y values corresponding to x values and also the measurement errors of...

Use the comparison test to determine if the series series convergences or divergences $$S_{6}=\sum_{n=1}^{\infty} \dfrac{1}{n^2 \ln{n} -10}$$ ok if i follow the example given the next step alegedly would be... $$\dfrac{1}{n^2 \ln{n} -10}<\dfrac{1}{n^2 \ln{n}}$$ $\tiny{242 UHM}$

I am reviewing and comparing a wide range of mathematical models that are being applied to a specific realm of wildlife biology. For the comparison of these models, and to weigh advantages/disadvantages of different aspects with regard to application, I need to characterize each model. As I do...

I am reading Houshang H. Sohrab's book: "Basic Real Analysis" (Second Edition). I am focused on Chapter 2: Sequences and Series of Real Numbers ... ... I need help with the proof of Theorem 2.3.9 (a) ... Theorem 2.3.9 reads as follows: Now, we can prove Theorem 2.3.9 (a) using the Cauchy...

Homework Statement A particle of mass m kg is projected under gravity with horizontal and vertical components of velocity U and V. There is horizontal resistance of magnitude mku, where k is constant and u is horizontal component of the velocity at t seconds. No vertical resistance present. (i)...

Hi PF! I'm solving a 2D PDE using NDSolveValueMesh. On one boundary I apply a Neumann BC. Attached are two plots: the top is the boundary condition and the functional value. Notice both are exactly the same. However, the lower plot shows a directional derivative evaluated on the same boundary...

Homework Statement This is a conceptual question I have, the binding energy per nucleon is mass defect*c^2/mass number while the packing fraction is mass defect/mass number. A higher binding energy per nucleon indicates a more stable nucleus BUT a smaller packing fraction indicates a more...

Hi, If we compare LWR and HWR (CANDU), which reactor type produces more waste per used Uranium? And also, between these reactors, is there a difference at the time required for the spent fuel to be completely safe? For LWR, It is around 100 000 years. But what about HWR? Thank you in advance.

Homework Statement You have decided to use a CCD camera to check if a 16th magnitude quasar is variable. With your telescope/camera combination, you know that a star with a magnitude of 0 would deliver 1 × 109 photons/second to one pixel, so this allows you to work out the photons/second from...

what are the dimensions of the double slits in comparison to the electron? what keeps the electron from decaying outside the environment of an atom long enough to run the experiment? how are the electrons detected before and after the slits?

I want to know what is the difference in atoms when a cell is alive and after it is dead

A disc and a hoop (ring) both of same mass and radius roll down an inclined plane of height "h". It is well known the disc has great velocity than that of the hoop at the bottom. I am fixed in the situation after they start rolling horizontally. Which will go farther? If the surface is...

Could someone help me in comparing 2 different thermal shock test profiles effect on a component. The 2 profiles are varied in deg C /min change and also the dwell time in low and high tempwratures. Any references are highly appreciated. Thank you

Homework Statement Homework EquationsThe Attempt at a Solution So the book is saying that this series diverges, i have learned my lesson and have stopped doubting the authors of this book but i don't understand how this series diverges. ok i can use the comparison test using 1/3n and 1/3n...

Carl Sontag wanted to compare what proceeds he would receive with a simple interest note versus a simple discount note. Both had the same terms: $19,500 at 8 % for 2 years. Use ordinary interest as needed. A. Calculate the simple interest note proceeds. B. Calculate the simple discount note...

The problem In this problem I am supposed to show that the following series converges by somehow comparing it to ## \frac{1}{k\sqrt{k}} ## : $$ \sum^{\infty}_{k=1} \left( \frac{1}{\sqrt{k}} - \frac{1}{\sqrt{k+1}} \right) $$ The attempt ## \frac{1}{\sqrt{k}} - \frac{1}{\sqrt{k+1}} =...

Hi. Found a circuit pre made at everycircuit and tryed to reproduce it for scratch but the new circuit does not work. I am as new to electronics as one can be, so that is why i ask if i don't understand something with these circuits or is this probably a bug with everycircuit? In image left is...

Hi, PF I have to comment this graphic about a reaction with and without catalysis. It's clear that the 'b' and 'c' line represent the catalysed processes, but I don't get one thing: my professor said that 'c' is a worse catalyst than 'b'. Why? Thank you

Greg Bernhardt submitted a new PF Insights post The Schwarzschild Metric: Part 3, A Newtonian Comparison Continue reading the Original PF Insights Post.

Homework Statement ##\sum _{n=0}^{\infty }\:\sin \left(\frac{1}{n}\right)## Homework Equations The Attempt at a Solution Can I try comparison test by ##\left(\frac{1}{1+n}\right)<sin\left(\frac{1}{n}\right)## since ##\left(\frac{1}{1+n}\right)## diverges also...

I have heard about a moon Enceladus. Which is powered by tidal force. I suppose this force press back and forth on the moon and friction in the core causes heat. I hope I'm right :-) Now tidal force ##F_t=\frac{2GMmr}{R^3}##, where ##G## is Gravitation constant, ##M## is mass of planet causes...