In this model, I want to simulate regarding changed in cirtain wheather conditions (e.g. solar radiation in a whole year), solar thermal collectors heat first the hot water tank. After hot water tank reaches to its max. allowable temperature, the excessive heat which comes from the solar collectors will be released to the ground. To simulate heat release, I use Bore hole single U-tube model with additional heat port. If the excessive heat is not released to the ground, the medium temperature(e.g. water) exceeds the allowable temperature of solar collectors which is 130 Celcius.
With which component should I connect the heat port of ground source heat exchanger, in order to simulate the ground which takes heat from the system and how much heat should I take out from the system?
SolarThermalConnectors connected with HotwaterTank and BoreHole
Unless the actual physical system is designed as you describe it, I would design it differently:
The hot water tank should decouple heat production and consumption — conceptually shown in the figure below.
The solar collector circulation pump controls the collector outlet temperature so that only hot water at the right temperature (e.g. 90 °C) is stored (in order to maintain a "sharp" thermocline). When the storage tank is almost full, energy-wise (e.g. 90 %), the borehole circulation pump should maintain the energy level by circulating water through the borehole exchanging heat with a fixed low ground temperature.
Related
I want to develop a model for heat transfer between two concentric cylinders in contact, one being heated and the second one passively cooled, but I am not really sure, what way would be the best to do it.
My plan is to use two two heat capacitors with heat capacity according to each material and a heat conductor between them. But I'm not really sure, if putting heat conductor in-between the cylinders is the right thing to do as the two cylinders are touching and there is nothing separating them. How to then calculate what should be the thermal conductance then.
Thanks for all of your suggestions.
I tried to make a model of heat transfer between two concentric cylinders in contact, but don't know, what is the best way, to do it, with thermal conductor or without.
It depends on your boundary conditions. It sounds like you have a combination of heat flux (inner face) - thermal conductance (cylinder 1) - thermal conductance (cylinder 2) - heat transfer coefficient.
You should be able to find the thermal conductance (or equivalently resistance) of a hollow cylinder in a heat transfer textbook, or compute the formula with the help of one, which you can then put in the thermal conductance components' parameters.
For simple boundary conditions, this will probably even be an analytic solution.
During the triangulation of a cell phone, we need to find out distance of cell phone from tower using signal strength on that phone. Is there any equation to calculate distance between tower and phone by putting signal strength in that equation? If yes, then what is that equation.
Please help
Theoretically, you should refer to some EM textbooks or Wiki (https://en.wikipedia.org/wiki/Signal_strength_in_telecommunications). It depends on your frequency band, GSM/3G/4G/5G/etc. It also depends on ground building (settlement) type, ground surface with lots of tall concrete buildings tends to block signal much more aggressively than a rural area with a grass plain.
Practically, you should do some physical measurement yourself because how your signal strength is computed (is it in log scale, linear scale, SNR, etc) does affect many things. Take note of near field effect, that is, when your cellphone is very very close to the station, the signal strength variation behaviour can be very different.
No, it is not so simple. At the very list you need to know the transmission power of the base station.
I am doing research on the tremors and Parkinson's disease.The plan is to use accelerometers and gyroscopes on the human arm. I plan on using Pulse for data collection and analysis. My questions are:
Is it true that there are some accelerometers that can separate gravitational acceleration from linear acceleration (heard it on the uncited grapevine). My suspicion is that we can't place an accelerometer on the patients arm to measure, say, the tremors caused by bicep and tricep contraction because if the patient rotates his wrist, the change in gravitational acceleration will contaminate our results. More to the point, can we measure acceleration due ONLY to the action of the muscles, and not due to changing gravitational forces with any of your accelerometers?
If a 3-axis accelerometer is rotating about an axis parallel to the ground, wouldn't the axis perpendicular to the ground pick up a sinusoidally varying (i.e. not DC) gravitational acceleration?
None of the accelerometers can separate the linear acceleration from the gravitational acceleration. This is achieved by sensor fusion, you merge the accelerometer and gyro readings in a clever way.
I developed a motion sensing applicaton to track human motion (elbow flexion). I am sure something similar would work fine for you.
My advice is to use orientation in your application (rotation matrices).
If you have to implement the sensor fusion yourself then the Direction Cosine Matrix IMU: Theory manuscript is a good place to start.
Attached is a piece of data with the iPhone in a pocket with the motorbike accelerating from 0 to 13 metres/sec (plot shown in green) and the raw accelerometer data (magnitude in g), the x-axis is in seconds. The speed is being sampled at 1 every second (using the GPS) and the accelerometer data is being sampled at 10 every second. Ideally if i were to accelerate at a constant rate (which is not the case on a motorbike or any vehicle) from 14s to 20s, i should have an acceleration of 13/6 = 2.16 m/s^2 = 0.22g above the stationary 1g (due to gravity). My assumption is that the forward acceleration will be much larger than the lateral movements (i.e. due to tilting of the bike, etc.), therefore allowing the magnitude of the x,y and z accelerometer components to be a good enough approximation of the forward acceleration of the bike. But as you can see, from 14s to 20s i get spikes in acceleration instead of a constant acceleration at 1.22g. This could be due to the bike not accelerating at a constant rate and the values that dip below 1g could be due to the jerk of the bike while accelerating. Any thoughts?
Two things:
Acceleration is a vector. I presume you're accelerating on a level track, so the accelerations will add like perpendicular vectors, so you should see an increase in magnitude of about 0.24 m/s = 0.024 g, which is barely visible on this scale (I think I see it, but I'm not sure).
The wiggle in the acceleration curve continues when you're cruising at high (but almost constant) speed. So it's not caused by jerks in the drive, it's caused by the bumpiness of the ride and maybe some 4-5 Hz resonance in the suspension. (The bumps don't seem to get faster, so I doubt it's an unbalanced wheel.)
Now that iOS 4 is no longer NDA, I would like to know what Gyroscope has to offer over the Accelerometer for developers. Is there a difference in APIs? Other things?
Actually, the accelerometer measures linear acceleration; but since force is equal to mass times acceleration, people can consider it as measuring force as well as long as it has a constant mass. Linear acceleration is the rate of change of linear velocity. A gyro on the other hand provides the angular rotational velocity measurement as oppose to the linear acceleration of movement. Both sensors measures the rate of change; they just measure the rate of change for different things.
Technically, it is possible for a linear accelerometer to measure rotational velocity. This is due to the centrifugal force the device generates when it is rotating. The centrifugal force is directly related to its rotational speed. As a matter of fact, many MEMS gyro sensors actually uses linear accelerometers to determine the rotational speed by carefully placing them in certain orientations and measuring the centrifugal forces to compute the actual rotational gyro speed.
A MEMs gyroscope is a rate of change device. As the device rotates in any its axis, you can see a change in rotation. An accelerometer only provides the force along the X,Y,and Z vectors, and cannot solve for "twist". By using both sensors, you can often implement what is referred to as a 6DOF (degrees of freedom) inertial system - or dead reckoning - allowing you to find the relative physical location of the device. (Note that all inertial systems drift, so its not stable in the long term).
In short: gyroscopes measure rotation, accelerometers measure translation.
There is a new API for reading the gyroscope.