What is performance: Definition and 258 Discussions

how can i get greater performance from an standard inverter duty motor( marathon black max). I am in the process of buiding an inverter/controller to use as part of an EV conversion.

This O2 Maximum Performance product is an energy enhancer. It's a bottle where you puff in 92% oxygen. I think most people would agree more oxygen = more energy, but I wonder how much just a few puffs will do for you. The bottle servings per container is about 60 puffs at $20. Most times...

Hi all, I have been thinking about an interesting concept. I have the laptop version of the 7800go and I know that most programs don't support laptop versions of GPU and hence most programs use them inefficiently and this results in poor performance. I have come up with a few solution...

Hi guys, Now I want to build a computer for intensive calculation. I am expecting to spend somewhere 4000 dollars just for machine. The only thing I must need is nvidia video card. hhd size isn't important but the speed is. Do you guys have any suggestion?

I need to perform standard set theory operations such as union, intersection, difference on sets of integer numbers. Each set can have a few hundred elements and each operation can involve a few hundred sets. The operations can easily be written in Java using the Java Collections Framework...

How come processors run faster under cold conditions and slower under hot conditions? I always assumed resitance would play an important part in this and if a processor is made up of some type of semiconductor then resistance would decrease with temperature thus allowing more current to flow...

How do low grades (say, Cs or lower) in general education courses affect graduate school admissions? In my case, I'm a pure mathematics major who is failing honors microeconomics. I just absolutely loathe the subject. How is this going to affect my future? Will they care, or just look at my...

Hello all, We would like to build a system in order to evaluate the performance of air-conditioning. Who can help us to disign this system or introduce the company where we can consult? thank you! Pham Vinh

can anybody help me with this question? A 10 stage instruction pipeline runs at a clock rate of 1GHz. The data forwarding scheme and the instruction mix are such that for 15% of instructions one bubble, for 10% two bubbles, and for 5% four bubbles must be inserted in the pipelin. The...

can anybody help me with this question? A 10 stage instruction pipeline runs at a clock rate of 1GHz. The data forwarding scheme and the instruction mix are such that for 15% of instructions one bubble, for 10% two bubbles, and for 5% four bubbles must be inserted in the pipelin. The...

For those who don't know, I'm an HVAC engineer. From time to time, the issue of heat pump efficiency comes up. When picking a system, obviously efficiency (cost) is important, so we need to decide between, usually, heat pumps (air source) and gas for a small split system. The government has a...

Greetings all! There is a bit of a debate in the world of mountain bikes, concerning the conventional 26" wheel diameter versus the rising popularity of the 29" wheel size (nominal diameters). One of the popular beliefs is that the 29" wheel requires a larger brake rotor than a 26" wheel...

Hi all, I have this stituation. Our favourite football team normally play very well. But recently, when they attended a tournament and they lost all the games ! They even lost to a team that they had never lost before. Their form was very weak at the time. I am not sure if there is a word or...

Just a couple of weeks ago, my laptop started making a very loud roaring noise and experienced a severe slowdown in performance (programs and windows open very slowly) at the same time. It takes a couple minutes after booting up for the noise to begin, but once it starts it is continuous. At...

Biologically, what does it do to provide more energy?

Questions come up time to time regarding stainless steels and special or high performance alloys. Manufacturers and suppliers have some technical information on their websites. For example, here are some major suppliers: High Performance Alloys, Inc. http://www.hpalloy.com/Alloys/...

Hi, I wanted to make an equation with Newtonian physics, but failed. Here's the problem: Consider an object with that ^ has m mass, and a built in drag & | magic motor that has P friction...

So I know that my CPU is now slowing down, even though Process Explorer reports system usage as varying between 30-70%, far short of 100% system usage. What is the most reliable way to measure system usage before the system starts to slow down?

Any one have any opinions on the differences between these two language (and their closeness to C)... chroot posted about python being almost as complete as java interms of standard libs. I attended a presentation which seemed to verify that claim though you have to download some of the added...

After waiting a week and a half she's here! http://photos-004.ak.facebook.com/photos-ak-sf2p/v78/133/69/5736845/n5736845_34678004_5514.jpg http://photos-005.ak.facebook.com/photos-ak-sf2p/v78/133/69/5736845/n5736845_34678005_5782.jpg Oh yeah, its Ultegra components...

Hi, Will a sun sensor work if the satellite is in the Earth's shadow? thanks!

[SOLVED] Water guns Currently on a forum about water guns there is a debate going on about what determines a water gun's performance between pressure and force. On one side are people who say that higher pressure differentials combined with a higher "Cv value" will mean more flow, which...

Hai I am using a double shroud fan wheel for our application. what will be happened, if i use the same dimensions fan wheel with single shroud ?. can u clariffy for the same in the following points. 1. Discharge 2. Total Head or static head or Dynamic head 3. Power With regards...

Hello everyone we were given this question to think about, and I wans't sure if my reasoning was right or not, what are your thoughts? #1. It is obvious that using more hardware results in better performance, but that the performance increase is not linear in the amount of hardware added...

Anyone familiar with GM tube, please share some experience on the effect of temperature to GM tube performance, how does it influence? I found our GM tube tally has increase a little as the temperature increased rapidly from 4 degree to 55 degree, I wonder is it a casualness or a indication of...

Hi everyone, I was hoping to ask a thermodynamics problem, specificially one about heat pumps and coeffiecent of performance. I am wondering if I am missing something. I am given that heat pump is heat a building. Inside temperature is to be maintained at 22 degree celcius, outside is...

Hi all, Im a Mech Eng student getting my 3rd year project underway, Using a simple ABS Disc Brake system model, i would like to analyse braking performance for calculations obtained with variations of brake pad size, mateial, and also different disc sizes and materials. My question...

It is always a big debate on mustang sites on whether a big X throttle body is not needed or that it will not hurt anything as far as the performance goes. Some say, "too much air can't hurt." Some say, "too much air can hurt."... Which one is it?

Well I have always been interested in engines and how to make them more efficient and make more power. Particularly the popular modifying of Ford and GM engines (302ci, 351ci, 350ci, etc.). I am looking for a book that could help me understand how a cam actually works, and what to tweak...

A Carnot refrigerator operating between -10.0 C and 40.0 C extracts heat from the cold reservoir at the rate 300 J/s. What are (a) the coefficient of performance of this refrigerator, (b) the rate at which work is done on the refrigerator and (c) the rate at which heat is exhausted to the hot...

Im a HVAC contractor/designer. I am looking to install a fan unit with a VFD. This is 3 phase, 60HZ, 460 volts, 40HP AC motor. Im trying to create a "system curve" like a fan curve that would show the cfms at various frequency settings being changed by the VFD. I can reiterate or...

I need to build a mousetrap car for a physics class and i was wondering if anyone could possibly give me any ideas on how to make the car travel faster and further. The requirements are that it needs to travel 25 ft for an A while carrying a full (closed) can of pop.Also, we can't use anything...

1. North vs. South. A heat pump is designed for southern climates extracts heat from the outside air, and delivers air at 20C to the inside of the houses. What is the average coefficent of performance of the heat pump: (Consider this to be a Carnot device) a) In the south where the average...

I wonder if anyone could shed some light or information about the subject I'm looking into. How will wind turbines with varied amounts of blades perform in varied wind speeds. E.g. the less amount of blades you have the better a turbine will perform at higher wind speeds? Any help on the...

I am considering writing a MATLAB program to montior the motor performance of my model airplane. I would have to do it through USB, because I only have one 232 port, so I can't use multiple devices from that one port. I would like to montior the temperature, voltage, current, power, static...

1)does a magnetic compass needle have high remanence or low remanence? 2)in a shell type transformer core required to carry DC in addition to normal AC, what effect does the introduction of an airgap have on AC performance of such transformers.

Every wonder what your boss is really trying to tell on his yearly performace review...

Hello all. I have the following questions regarding the analysis of the performance of a rotary vane compressor. 1) Why can the specific kinetic and potential energy changes normally be neglected? 2) If an adiabatic compression is considered, what is the primary cause of energy loss...

(hehe here's another one for you dduardo :biggrin: ) Does anyone know if STL is used or is capable of being used in large system simulations? Or is it best to write your own datastructtures? Looking to do some computational astrophysics or large neural nets and am not sure whether to use STL...

I had a midterm today, and I think I did bad on it even though I studied hard for it. When I first glanced at the paper, I knew how to every problem. But when I started to each problem, my neck started to go stiff, and I couldn't think properly. It seems as if though everything I studied...

Why are communication parameters important when a computer uses a modem? Thank you in advance

In the states there is a positive stereotype about the high performance of Asian students academically, particularly in the maths and sciences. I have heard there is a study of american students that showed asians scoring an average of 10 points higher IQ than other groups, but this is...

I'm now a programmer in a Shanghai based IT company. I have been graduated from college for 4 years and my major in college is not math or physics related. But I kept thinking my "philosophical stuff" along and recently found there's answers for me in both pure mathematics and theoretical...

I'm sure most of you have heard of the Einstein Referigeration Cycle . For those who have not I've listed the references for further reading.. http://www.me.gatech.edu/energy/pubs/SLA_2.pdf ok 342 K is about 156 F ,for anyone with an attic , it seems to me that this is the perfect solution to...

Does an aluminum wire have any performance disadvantages other than having to be thicker to carry the same amount of current?

This question is killing me because I just can't seem to get it. A heat pump is used to heat a house in winter; the inside radiators are at T_h and the outside heat exchanger is at T_c. If it is a perfect (e.g., Carnot cycle) heat pump, what is K_pump, its coefficient of performance? Give...

Does anyone know where I can find 3 Volt DC Motor Performance Graphs on the web? I'm looking for something like this, but with a 3 Volt motor. My googling has yet to find any relevant results. Thanks in advance.

how can I find efficiency of heat engine operating between two differenct temperatures?

Can someone give me some examples of factors that affect the performance of ribbon cable please.

Hi, This is not a physics question. However, I was hoping someone could help me. A call centre sets a quality target of answering the telephone within 30 seconds. The results of monitoring show a normal distribution with an average answer time of 28 seconds and a standard deviation of 2...