# All Questions

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7 views

### Tuning an eBay PID: REX C100

I have a PID controller which exhibits an odd behaviour. I understand that the P value should be incremented until the measured value oscillates. For my unit, with I = 0 and D = 0, if I take P above 5,...
8 views

### How does microphone -> software work?

I've read this: "A microphone converts sound into a small electrical current. Sound waves hit a diaphragm that vibrates, moving a magnet near a coil. In some designs, the coil moves within a ...
18 views

### Gear/Mechanics problem: How to design to allow for 2 types of rotation

I am designing a new mowing system that can effectively mow around poles. The machine consists of an arm that is attached to the back of a tractor and runs off its PTO. At the end of the arm is a ...
34 views

### High pass filter and differential equation relationship

Consider the problem stated as follows: A signal y passes through a high pass filter $\frac{s}{s + ω }$. A high pass filter with cutoff frequency ω isolates the variations of this optimized variable ...
17 views

### Aligning Dead and Live Center of Lathe

How can one go about aligning the dead and the live centers of a lathe ?
30 views

### What has changed since the 1990s that made “LED lights” possible?

I keep seeing all kinds of objects now having small but very bright LED lights in them, seemingly never burning out, requiring almost no batteries/power, and extremely durable. I remember being a ...
13 views

### How to get my product IEC tested and certified

What is the procedure to get proper IEC certification for a product? What is cost of such action? I am talking about, let's say, a fan or an oven (if size and complexity of product makes any ...
17 views

### Solving single phase no load transformers questions

1000/100 V, 10kVA, single-phase transformers impedance referred to HV side given as (5+j10). The no-load power of the transformer is given as 300W. What is the efficiency of the transformer at full ...
28 views

### Can Sheet Metal Be Formed With Bends At Weld Joints?

I understand that a weld, if done properly, is stronger than the base metal. Does this mean that if you have a part that needs to be formed, the bend can be made along the weld? Or is the weld filler ...
11 views

### Is there an instrument that can measure thickness of an object through strain?

So basically, I am doing a project to design a measurement tool for measuring the different layers of the quartz crucible used in the semiconductor industry. Since the crucibles undergo some ...
12 views

### Can carbon fibre be injection molded?

I found very little information about that, but it says that its technically possible, but then why it isnt used instead regular carbon fibre machining? It sounds way easier...
13 views

### In ASD do you divide elastic or ultimate strength?

In Allowable Stress Design (ASD) method, to find the allowable stress, do you divide the ultimate stress or the elastic stress (where the material becomes plastic) by the factor of safety? For example ...
10 views

### The difference between two load combinations in LRFD

In ASCE 7-16 there is a load combination as: 1.2D + 1.0E + L + 0.2S but then there is also another combination as: 0.9D + 1.0E In both of them earthquake load is the same so why would we use the ...
29 views

### Interaction of buckling modes

I'm reading this paper on structural members subject to both bending and compression. In the first paragraph, in context of the equations 6.61 and 6.62, it is said: The second two terms are modified ...
33 views

### how can I control 2 stepper motors with RS-232?

Hello everyone this is my first post to the forum. I want to control 2 stepper motors using RS-232 as a way of directly communicating with step drivers from my desktop. I am new to communication ...
20 views

### How to pre-process paint residue prior to an RO system?

I am planning to install a reverse osmosis (RO) waste system that will purify waste before putting it into a drain. However there are certain substances like fibrous matter, fats, grease and ...
36 views

### Why are actions combined in this way Eurocode?

Reading here on Eurocode. It says that when a cross section is subject to both normal force and moment their effect should be combined like this: \frac{N_{Ed}}{N_{Rd}} + \frac{M_{y, Ed}}{M_{y,Rd}} + ...
12 views

### Convert values of utilization category from AC7a / AC7b to AC5a / AC5b - Is it possible to estimate?

I have a contactor which is rated at 440V and 25 A for utilization category AC7a and 8.5 A for AC7b. Is it possible to give an estimate about the maximum current and power usage for appliances of ...
17 views

### Why is the direction of angle theta in circular motion towards and inwards? [duplicate]

(You can ignore text in the image if not understood , I have edited all of that here as well) Why is the direction of angle $\theta$ in circular motion towards and inwards of plane xy axis? I am not ...
34 views

### Is this alternate grounding practice practically implementable?

While grounding power sockets in modular prefabricated steel buildings (see Light Gauge Steel Frame Technology), can we just connect the ground wire to the steel frame of the building itself? as the ...
36 views

### How to cut a thick glass block at home?

Due to pandemic, there are a lot of machine shops closed and delays in getting something custom made. I was wondering how to cut a triangular glass prism (~5cm hypotenuse) in the middle so I have two ...
17 views

### Bosch K-Jetronic Fuel Injection

Why people always say K-Jetronic will not work with high performance high duration cams and because of this the K-Jetronic equipped engines will not be making lots of power. In Bruce Andersons book &...
29 views

### Can anyone help me with this problem of rpm of lathe? [closed]

Calculate the revolutions that you would place on the lathe knowing that we are going to turn a piece of mild steel, 110 mm in diameter, with a cobalt tool.
45 views

### Given 3 force measurements, what are estimated forces at other locations?

Given three unequal force measurements spaced equally 120 degrees apart on a circular plate at F_R, F_C, F_L, I need to calculate what the estimated force measurements would be if taken at positions ...
23 views

### Tempering 1095 steel

I have some laser-cut filing templates, about the size of a business card, made from 3mm-thick 1095 carbon steel. These parts will be used to guide a round metal file when filing odd shaped holes in ...
20 views

### 24 hr stand alone real time clock module/IC [closed]

Can you please suggest a suitable stand alone IC/module that outputs a pulse once every 24 hrs. I suspect there exist a complete module with battery, 32 kHz crystal and freq divider IC combined, but I ...
32 views

### Why Stirling engine not used as primary source to operate generator in thermal power plants?

I did some research and found out that in order to generate that amount of electricity( consider about 100MW) the size of the Stirling engine will be very big as compared to that of a steam turbine. ...
27 views

### Calculate the thrust of a fan

I'm having some difficulty with the following problem: The fan operating parameters are adjusted to reduce the constant negative pressure at the inlet ($p_\infty-\Delta p$) within a certain range of ...
20 views

### Is there any way to focus the mechanical vibration or stress of an object?

I am looking for a way to focus the vibration of a metal sheet at a specific point on that sheet so that other points vibrate less. Just like light and lens. Is there any way to focus the mechanical ...
51 views

### What is the type of pavement defect and how to address the issue?

Attached image is from a very high water table and high salinity area. What is the type of pavement defect and how to address the issue?
51 views

### Effect of frequency resolution on the frequency spectrum of impulse force delivered by an electromagnetic shaker

this is a part of my parameter study for the experiment (a vibration analysis with a force impulse input). This specific part studies the frequency resolution effect on the spectrum. The input (i.e.: ...
40 views

### Least force required

Relying on my past knowledge on how to attack the problem, I should use the equation Moment of B about AC = $r_{AB} \times B • n^ AC$ To find the least force on B. I just don't know what position ...
24 views

### Ramp up during build phase of oil production [closed]

Why is it important to ramp up during the build phase of oil production?
28 views

### Phasor representation of RC circuit

I am struggling to understand how to take the KCL equation from time domain to Phasor domain. The time domain KCL equation is easy to understand and represented here: The phasor domain equation looks ...
26 views

### Wireless communication modules transmitting through body

I wanted to be able to transmit data from a wireless module to an Arduino. It is possible that a human body could come between the wireless module and the Arduino or someone might cover up the module ...
23 views

### What really is the difference between allowable stress design and ultimate limit state design?

I'm trying to understand this difference. From what I've read, ASD basically deals with making sure the stress in a structure does not exceed a certain limit, the yield stress of the material. It ...
15 views

### How to solve this question relating to string [closed]

There are two string of mass 100g and a inextensible string(0g).length of string is 1m. There is load of 100kg. Where should the load be placed so that the string breaks in the minimum amount time ...
16 views

### Do we mean the normal reaction caused between the water and block [closed]

By resultant B of the contact force , do we mean the normal reaction caused between the water and block in this theory part section.
56 views

### Multiturn rotational limit switches

I would like to automate a door lock. For reasons I won't get into, I'm not allowed to modify the lock itself, I can only attach things to the "safe side" of the door. On this safe side, ...
659 views

### Unknown circuit component with glass encapsulated contacts

This is an unsoldered circuit component that had two metal pieces that weren't making contact inside a thin glass tube. What is this? I haven't seen anything like it before.
31 views

### Heat rate through composite wall with non-constant thermal conductivity

I just started a job working with cryogenics and I am trying to solve an interesting heat conduction problem that I was hoping someone could help me along with. I have a structure that spans from room ...
30 views

### Finding the reaction force at the hinge

The question given is A uniform rod, of mass $m$ and length $2a$ smoothly hinged to a vertical wall is connected to a point on the wall above the hinge by a light inelastic string. Find the magnitude ...
22 views

### Meaning of this sentence in lecture notes about buckling of nonlinear column

Above picture is from my lecture notes. It deals with a column subject to axial load, which follows Euler buckling theory. The material is nonlinear, approximated by two lines as seen in the stress-...
125 views

### Why is the direction of pressure always perpendicular to surface area for fluids?

Why is the direction of pressure always perpendicular to surface area of a body for fluids ? We also assume that it is an ideal fluid here. So , pressure acts in all directions because fluid has a ...
25 views

### Constructing small Kretschmann Surface plasmon set up

I am trying to build a SPR setup at home which is based off this diagram: I wanted to try to miniaturize it and had some concerns about my strategy. So I was thinking I could buy a big prism and ...
13 views

### Finding all the pressure acting on base of cylidner

Water is filled in a flask up to a height of 20 cm. The bottom of the flask is circular with radius 10 cm. If the atmospheric pressure is $1.013 \times 10^5$ Pa,find total force exerted on the bottom ...
21 views

### Why is the atmospheric pressure given as the value of length of mercury column in barometer

Why is the atmospheric pressure given as the value of length of mercury column in barometer. Since the density for the both the cases are different. Is it that by experiment we found the value to be ...
9 views

I am trying to solve problems on radix-4 (DIT & DIF) numerically. Unlike radix-2, when N = 8, and the values of x = {1,-1,0,2,1,-2,-1,0}, where n = 0,1,..., N/2 - 1. This, I can solve without ...