Saturday, January 15, 2011

CrazyEngineers Forum

CrazyEngineers Forum

Sharing xScribble - a Gtalk client with graphical chat functionality

Posted: 15 Jan 2011 09:50 AM PST

Hi all,
xScribble is an app I developed with the help of my friends as our Mini project at college. It is a Gtalk client, and the twist is that it enables graphical chat. Now you can literally draw in gtalk chats.
xScribble provides you with a canvas where you can draw simultaneously with your friend over the internet.

I thought I'd share it on CE so that I can get valuable feedback from all the crazy computer science engineers. Just take a look at the xScribble page and let me know what you think!
Your suggestions will be really helpful, since we're planning to extend the same idea as our major project as well! :)

My Friend Needs Help

Posted: 15 Jan 2011 08:41 AM PST

hi every body. Actually my friend name is megha. she is a nice girl. But she will get angry even at small things. many of my friends are victims of her anger. she doesn't do all these it wantedly . she is not aware that she is hurting her friends due to her anger. i want that she should know her mistakes. Many times i tried to express this with her. but i was afraid that i may loose her. Due to this fear Iam not able to express this. If i did not express this she may loose many of her friends. I don,t no what to do. Iam confused. I didn't know whether this a right platform to share this or not(if not iam really sorry). please give your suggestions what i have to do now.

steam rankine cycle..

Posted: 15 Jan 2011 08:30 AM PST

in simple rankine cycle the the hot steam from the boiler is passes through the turbine to produce shaft work.. after this that steam get condensed which still contains good amount of energy. so i just want to know that why we does not use that remaining energy contained in steam, by again passing it through turbine for its fully utilization or in other words why we need to condense it ? ?

Kriya - PSG Tech - All in One Events

Posted: 15 Jan 2011 07:16 AM PST



KRIYA, the brainchild of the Students Union, PSG Tech, is the conglomeration of the elite brains across the Indian heartland. It is the biggest conflux of students, industry and academia for a thoroughly enriching experience. Be it a video conference from eminent technocrats or guest lectures from industry stalwarts or technical events which test the Einstein within you or workshops which educate and enrich, Kriya has it. Come and be enlightened in the Zenith of Innovation!

Prayatna - Mechanical Engineering - PSG College of Technology, Coimbatore

Posted: 15 Jan 2011 07:14 AM PST

Yes its up
All in events for Mechanical Engineers at PSG Tech
Just check here
PRAYATNA '11

about grounding

Posted: 15 Jan 2011 06:59 AM PST

hey friends,
i got a doubt
some where i listened as grounding means connecting to a metal is it right if so why we are using the metal from the ground by marking as grounding and another thing is which metal we use as grounding as my knowledge metal can be any cheap metal am i right
please answer to it friends

Elements of a Process Control System

Posted: 15 Jan 2011 06:32 AM PST

Elements of a Process Control System






INTRODUCTION
-The term automatic process control came into wide use when people learned to adapt automatic regulatory procedures to manufacture products or process material more efficiently. Such procedures are called automatic because no human (manual) intervention is required to regulate them.
-All process systems consist of three main factors or terms: the manipulated variables, disturbances, and the controlled variables. Typical manipulated variables are valve position, motor speed, damper position, or blade pitch. The controlled variables are those conditions, such as temperature, level, position, pressure, pH, density, moisture content, weight, and speed, that must be maintained at some desired value. For each controlled variable there is an associated manipulated variable. The control system must adjust the manipulated variables so the desired value or "set point" of the controlled variable is maintained despite any disturbances.







Elements of a Process Control System
-The following figure illustrates the essential elements of a process control system. In the system shown, a level transmitter (LT), a level controller (LC), and a control valve (LV) are used to control the liquid level in a process tank. The purpose of this control system is to maintain the liquid level at some prescribed height (H) above the bottom of the tank. It is assumed that the rate of flow into the tank is random. The level transmitter is a device that measures the fluid level in the tank and converts it into a useful measurement signal, which is sent to a level controller. The level controller evaluates the measurement, compares it with a desired set point (SP), and produces a series of corrective actions that are sent to the control valve. The valve controls the flow of fluid in the outlet pipe to maintain a level in the tank.






-Thus, a process control system consists of four essential elements: process, measurement, evaluation, and control. A block diagram of these elements is shown in the following figure. The diagram also shows the disturbances that enter or affect the process. If there were no upsets to a process, there would be no need for the control system. The figure also shows the input and output of the process and the set point used for control.










PROCESS
In general, a process consists of an assembly of equipment and material that is related to some manufacturing operation or sequence. In the example presented, the process whose liquid level is placed under control includes such components as a tank, the liquid in the tank, and the flow of liquid into and out of the tank, and the inlet and outlet piping. Any given process can involve many dynamic variables, and it may be desirable to control all of them. In most cases, however, controlling only one variable will be sufficient to control the process to within acceptable limits. One occasionally encounters a multivariable process in which many variables, some interrelated, require regulation.




MEASUREMENT
- To control a dynamic variable in a process, you must have information about the entity or variable itself. This information is obtained by measuring the variable.
- Measurement refers to the conversion of the process variable into an analog or digital signal that can be used by the control system. The device that performs the initial measurement is called a sensor or instrument. Typical measurements are pressure, level, temperature, flow, position, and speed. The result of any measurement is the conversion of a dynamic variable into some proportional information that is required by the other elements in the process control loop or sequence.






EVALUATION
- In the evaluation step of the process control sequence, the measurement value is examined, compared with the desired value or set point, and the amount of corrective action needed to maintain proper control is determined. A device called a controller performs this evaluation. The controller can be a pneumatic, electronic, or mechanical device mounted in a control panel or on the process equipment. It can also be part of a computer control system, in which case the control function is performed by software.




CONTROL
The control element in a control loop is the device that exerts a direct influence on the process or manufacturing sequence. This final control element accepts an input from the controller and transforms it into some proportional operation that is performed on the process. In most cases, this final control element will be a control valve that adjusts the flow of fluid in a process. Devices such as electrical motors, pumps, and dampers are also used as control elements.




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Process and Instrumentation Drawings
-In standard P&IDs, the process flow lines, such as process fluid and steam, are indicated with heavier solid lines than the lines that are used to represent the instrument. The instrument signal lines use special markings to indicate whether the signal is pneumatic, electric, hydraulic, and so on. two types of instrument signals are used: double cross-hatched lines denote the pneumatic signals to the steam control valve and the process outlet flow control valve, and a dashed line is used for the electrical control lines between various instruments. In process control applications, pneumatic signals are almost always 3 to 15 psig (i.e., pounds per square inch, gauge pressure), and the electric signals are normally 4 to 20 mA (milliamperes) DC (direct current).










- A balloon symbol with an enclosed letter and number code is used to represent the instrumentation associated with the process control loop. This letter and number combination is called an instrument identification or instrument tag number.
- The first letter of the tag number is normally chosen so that it indicates the measured variable of the control loop. In the sample P&ID shown, T is the first letter in the tag number that is used for the instruments in the temperature control loop. The succeeding letters are used to represent readout or passive function or an output function, or the letter can be used as a modifier. For example, the balloon in Figure marked TE represents a temperature element and that marked TIC is a temperature-indicating controller. The line across the center of the TIC balloon symbol indicates that the controller is mounted on the front of a main control panel. No line indicates a field-mounted instrument, and two lines means that the instrument is mounted in a local or field-mounted panel. Dashed lines indicate that the instrument is mounted inside the panel.


- Normally, sequences of three- or four-digit numbers are used to identify each loop. In our process example, we used loop numbers 100 and 101. Smaller processes use three-digit loop numbers; larger processes or complex manufacturing plants may require four or more digits to identify all the control loops.
- Special marks or graphics are used to represent process equipment and instruments. For example, in our P&ID example in Figure two parallel lines represent the orifice plate that is used to detect the discharge flow from the process heater.

All about Pointers

Posted: 15 Jan 2011 06:19 AM PST

Let us discuss everything about pointers, starting from basic definition to each and every error that generally occurs while doing programming in c++ through this thread


I am sure it will help a lot of students

Earth-Conductor or not

Posted: 15 Jan 2011 05:35 AM PST

earth acts as a conductor for dc but not for ac..
this statement is correct i know but can anyone elaborate it furthur..
i am not getting its explaination and why it is so...?
plz help me out...

Other use of sandpaper

Posted: 15 Jan 2011 12:36 AM PST

Sandpaper is used in smoothing rough surfaces. Other than than that it is used in drawing.
Like this: The Civil Phil: The Sandpaper

Jto

Posted: 14 Jan 2011 11:33 PM PST

which book is best for JTO exam ?

English Mistakes You Should Avoid: Because they make you look Dumb

Posted: 14 Jan 2011 09:38 PM PST

At CE, we follow use of proper English language (instead of SMS language or slangs).
But many-a-times, I stumble across basic English grammar mistakes used by CEans.

I am trying to point out some of the mistakes that I find frequently. I hope that you will read it carefully and keep in mind so that it helps you everywhere and not just on CE.

1. Difference between You're and Your

You're = You are.
e.g. You're very good at programming.
And for your,
e.g. I am annoyed by your lies.
Same is the case with : they're and their

2. Use of Letter 'I'

The letter I that one uses to refer to himself is never written in small caps.
You should never write a statement like this:
"i am sorry. i did not know."

3. Difference between effect and affect

Affect is a verb. Effect is a noun.
You can not use them interchangeably.
e.g. When you affect something, it creates effect on that thing.

4. Difference between loose and lose

Loose is an adjective. Lose is a verb.
Loose means "not tight"
Lose means "not to win"
e.g. You might lose the match.
Your pants are loose.

5. Difference between it's and its

The difference may not seem significant to the average writer, but they are 2 completely different words.
Its is a pronoun, meaning "belonging to it."
While It's is a contraction of "It is" (like don't for do not).
e.g. This is a new chair. Its material is plastic.
e.g. It's not fair.


There are many more mistakes that we do unknowingly. I will add more points as and when I point them out frequently.

Power Consumption Monitoring

Posted: 14 Jan 2011 08:28 PM PST

Hi

i intend to work on a project where i find the energy consumed by each device of a house/office and give it to a Computer so that user may use the information to reduce his power consumption wherever required

Though i am going through online literature for this i have a doubt:

Is it necessary for me to monitor the energy consumed at each instant or can i find the power consumed by a device (say for eg air conditioner) once and based on its ON time i can multiply them to find the energy consumed.

Project Idea for Computer Science: GPS Based Auto Fare Mobile Application

Posted: 14 Jan 2011 08:08 PM PST

Many people in India daily face problems in commuting through auto-rickshaws due to false fare claims by the rickshaw drivers.

It would be great if you develop an application that dynamically calculates the distance traveled using Global Positioning System (GPS) and hence the fare due.

This project will enable the commuter to get accurate fare from auto-rickshaws.

It can be started as one enters the auto-rickshaw and the meter in the phone will run alongside the auto's meter.
Using the GPS, it can double-check the distance traveled as shown in the auto and calculate the exact fare.

Does the idea appeal to you? I am sure it will be of great help if the application is developed for all kinds of Mobile OS.

Hello from Maya

Posted: 14 Jan 2011 07:48 PM PST

hi,
how are you?
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