Force

In order to achieve several small scale and large scale objectives in various electronic circuits, it is highly essential to regulate the voltage supply, given to electronic circuits. This project, namely Variable Voltage Regulator, aims at fulfilling such small goals, using the 3-terminal voltage regulator LM317. The circuit consists of an IC LM317 and a set of resistors and capacitors, in addition to the transformer and the rectifying element.

The AC voltage, from the mains supply is initially stepped down to the desired voltage, which is then rectified to be applied to the input terminal of the voltage regulator IC. As mentioned earlier the voltage regulator then takes care of supplying a constant voltage at the output terminal. This voltage can be varied according to our requirements with the help of a variable resistor. This project designed has the ability to vary the voltage values from 1. 5V to 25V at an output current of 1A.  The LM317 is versatile in its applications, including uses in programmable output regulation and local on-card regulations.

Typical other applications of the voltage regulator circuits include the following:

• 5V Logic Regulator with Electronic Shutdown
• Slow Turn-On 15V Regulator
• High Stability 10V Regulator
• 0 to 30V Regulator
• Power Follower
• High Gain Amplifier
• 4A Switching Regulator with Overload Protection
• Precision Current Limiter
• Tracking Preregulator
• AC Voltage Regulator

Digitally Selected Outputs Besides replacing fixed regulators, the LM317 is useful in a wide variety of other applications. Since the regulator is “floating” and sees only the input-to-output differential voltage, supplies of several hundred volts can be regulated as long as the maximum input to output differential is not exceeded, i. e. , avoid short-circuiting the output. IC – LM317 D1-D4 – 1N4007 diode C1 – 2200µF, 50V electrolytic capacitor C2 – 0. 1µF, ceramic disc capacitor C3 – 10µF, 40V electrolytic capacitor C4 – 22µF, 35V electrolytic capacitor R1 – 47? , 1/4W resistor R2 – 10? , 1/2W resistor R3, R4 – 100? , 1/2W resistor VR1 – 1k? 1/2W wire wound potentiometer LEDs – green, red 1. IC LM317: An Adjustable Linear Voltage Regulator  LM317 is the standard part number for an integrated three-terminal adjustable linear voltage regulator. LM317 is a positive voltage regulator supporting input voltage of 3V to 40V and output voltage between 1. 25V and 37V. A typical current rating is 1. 5A although several lower and higher current models are available. Variable output voltage is achieved by using a potentiometer or a variable voltage from another source to apply a control voltage to the control terminal.

LM317 also has a built-in current limiter to prevent the output current from exceeding the rated current, and LM317 will automatically reduce its output current if an overheat condition occurs under load. LM317 is manufactured by many companies, including National Semiconductor, Fairchild Semiconductor, and STMicroelectronics. Although LM317 is an adjustable regulator, it is sometimes preferred for high-precision fixed voltage applications instead of the similar LM78xx devices because the LM317 is designed with superior output tolerances.

For a fixed voltage application, the control pin will typically be biased with a fixed resistor network, a Zener diode network, or a fixed control voltage from another source. Manufacturer datasheets provide standard configurations for achieving various design applications, including the use of a pass transistor to achieve regulated output currents in excess of what the LM317 alone can provide. LM317 is available in a wide range of package forms for different applications including heatsink mounting and surface-mount applications.

Common form factors for high-current applications include TO-220 with part number LM317T and TO-3 with part number LM317K. LM317 is capable of dissipating a large amount of heat at medium to high current loads and the use of a heatsink is recommended to maximize the lifep and power-handling capability. LM337 is the negative voltage complement to LM317 and the specifications and function are essentially identical, except that the regulator must receive a control voltage and act on an input voltage that are below the ground reference point instead of above it

These voltage regulators are exceptionally easy to use and require only two external resistors to set the output voltage. Further, both line and load regulation is better than standard fixed regulators. Also, the LM117 is packaged in standard transistor packages which are easily mounted and handled. The general circuit of a voltage regulator circuit containing LM317 is as given below:  Normally, no capacitors are needed unless the device is situated more than 6 inches from the input filter capacitors in which case an input bypass is needed.

An optional output capacitor can be added to improve transient response. The adjustment terminal can be bypassed to achieve very high ripple rejection ratios which are difficult to achieve with standard 3-terminal regulators. Here we have designed the circuit according to the required specifications of the output current and output range of voltage. Before analyzing the design and calculation part, let us look into the general operation of the circuit for the variable voltage regulator.

1 is the mains step down transformer (12-0-12), with a current rating of 500mA. It supplies a voltage of 12V or 24V to the regulator circuit. C1 is the main filter capacitor. The unregulated DC voltage across C1 at no load forms the input to LM317 regulator. The LM317 is a complete regulator. It has internal feedback, regulating voltage and current passing elements. In operation an accurate reference voltage, typically 1. 25V is developed between the output and adjust terminals.

This reference voltage, when impressed across the resistor R1, sets up a current I1 that equals Vref/R1 in R1. I1 together with the quiescent current Iadj from the adjust terminal of the IC flows in the output set resistor R2, so that the voltage across R2 is V2 = (Vref/R1 + Iadj)*R2 The output voltage Vo at the output terminal of the IC is hence Vo=Vref + V2, given by Vo = Vref + (Vref/R1 + Iadj)*R2 Or Vo = Vref(1+R2/R1) + Iadj. R2 he LM317 is designed to minimize Iadj, this being an error term and also to make Iadj independent of line and load changes.

To achieve this quiescent current is returned to the output terminal, thus establishing a minimum load current requirement. If the Iadj is neglected then the output voltage is then given by: Vo = Vref(1+R2/R1) In our project, this output voltage is available from a range of 1. 5V to 25V. This is attained with the help of the variable resistor, whose value can be varied to change the Iadj value and consequently get the desired voltage value at the output .

Quality is a continuous process that can be broken anywhere in the system of supply and customer service. By letting every person know how their activities help fulfill customer’s requirements, the organization can motivate their employees and suppliers to provide quality consistently. They must also realize that throughout the organization they will have both internal customers and suppliers similar to those outside the organization.

In general a process helps to change a set of inputs (i. e. resource, equipment, material and methods etc.) into desired outputs in the form of products or services. It is obvious that for certain aspects of an organization there will be various processes taking place, for example an organization may be involved in budgetary processes, accounting processes, salary and wage processes, costing processes, production processes, etc. Each process in every organization can be described by a proper investigation of the inputs and outputs of that organization. This will help to determine the action to be taken for the improvement of quality (Boznak, 1989).

The people who recently visited various quality companies in Japan and USA will tell that the central philosophy of all these companies is ‘Kaizen’ or loosely translated from the Japanese ‘continuous improvement’ and the quest for quality is a continuous cycle (Alic, 1988). The process on which continuous improvement is based is generally known as the Deming wheel. However, this wheel shows a continuous movement in a certain direction as shown in Fig. 1. The idea behind this is that the input which generates activities with measurable output is processes and the perfection of the process is the ultimate objective.

In Deming’s wheel the plan defines the process which ensures documentation and sets measurable objectives against it. The do executes the process and collects the information required. The check analyses the information in suitable format. The act obtains corrective action using total quality management techniques and methods and assesses future plans. At the end of each cycle the process is either standardized or targets are adjusted based on the analysis and the cycle continues. The link between customer/supplier with process improvement can be seen in Fig. 2 above.

Total Quality Management Approach As we know that many organizations in the United States of America are now also quality performers and there is a very good chance of a ‘gripping’ effect on the markets of European organizations that do not follow the quality improvement process. These United States organizations that have already achieved substantial advantage in their domestic markets by keeping the Japanese organization at a distance, are now well equipped to develop their market in Europe where the companies are just waking up to the quality improvement revolution.

Quality is now more of a survival kit for many European companies and without proper care and consideration they will be squeezed by the United States of America and Japan (Alic, 1988). In developing quality performance, various organizations in the United States did not follow completely the Japanese method of quality improvement; instead they have considered the country’s basic cultural issues in order to achieve the required quality in every aspect of their activities. By introducing quality improvements in this way they have developed quality ethics in their own organization with their own quality culture.

Even in recent times most people have blurred ideas about quality and some of them still like to equate quality with expense. However, we know that it is possible to pay a high price for an inferior product or service and at the same time one can easily obtain high quality goods and services at a lower price. However, there is no doubt in our minds that the quality has now been used as a modem competitive weapon and to manage it we must understand it clearly.

Modern concept of quality is defined as conformance to requirements and requirements are defined as the task to be accomplished in meeting customer needs. Quality cannot be inspected into the products or services, the customer’s satisfaction must be designed into the whole system. The conformance check then makes sure that things go according to plan. In general total quality management is defined as follows: Quality–is to satisfy customer’s requirements continually. Total quality–is to achieve quality at low cost.

Total quality management–is to obtain total quality by involving everyone’s daily commitment. The ability to fulfill the customer requirement is essential not only between two companies but with the same company. There exists in every organization, every department, every section and even every small unit a series of customers and suppliers. The secretary of a department is a supplier to the head of the department. She has to meet her customer’s requirements (Edson & Shannahan, 1991)

Quality is a continuous process that can be broken anywhere in the system of supply and customer service. By letting every person know how their activities help fulfill customer’s requirements, the organization can motivate their employees and suppliers to provide quality consistently. They must also realize that throughout the organization they will have both internal customers and suppliers similar to those outside the organization. In general a process helps to change a set of inputs (i. e. resource, equipment, material and methods etc.

) into desired outputs in the form of products or services. It is obvious that for certain aspects of an organization there will be various processes taking place, for example an organization may be involved in budgetary processes, accounting processes, salary and wage processes, costing processes, production processes, etc. Each process in every organization can be described by a proper investigation of the inputs and outputs of that organization. This will help to determine the action to be taken for the improvement of quality (Boznak, 1989).

The people who recently visited various quality companies in Japan and USA will tell that the central philosophy of all these companies is ‘Kaizen’ or loosely translated from the Japanese ‘continuous improvement’ and the quest for quality is a continuous cycle (Alic, 1988). The process on which continuous improvement is based is generally known as the Deming wheel. However, this wheel shows a continuous movement in a certain direction as shown in Fig. 1. The idea behind this is that the input which generates activities with measurable output is processes and the perfection of the process is the ultimate objective.

In Deming’s wheel the plan defines the process which ensures documentation and sets measurable objectives against it. The do executes the process and collects the information required. The check analyses the information in suitable format. The act obtains corrective action using total quality management techniques and methods and assesses future plans. At the end of each cycle the process is either standardized or targets are adjusted based on the analysis and the cycle continues.

The Physics of an MRI Machine. Whitney Wright PH106/006 Dr. Probst 06/05/2012 The Physics of an MRI Machine There are many physical concepts used in a Magnetic Resonance Imaging, also known as MRI, machine. There are many physical concepts used when an MRI is taken of the body, such as; radio waves, resonance and pulse sequences, magnetic fields being produced and lastly, magnets. Radio waves much stronger than the magnetic field of the Earth are sent through the body which causes the nuclei in the body to move to a different position.

When the nuclei move back to the place they originated from, they send back radio waves that the scanner on the machine picks up and turns them into a picture. Resonance is very common within multiple branches of physics, without resonance we wouldn’t have television, music or radio. Resonance is also one of the most unexplained phenomenons in physics; it causes glass to break with a high pitched voice, bridges to collapse and also earthquakes causing buildings to collapse.

Within the MRI, nuclear magnetic resonance is used, this is when magnetic fields and radio waves cause the atoms in the body to give off tiny radio waves (Bellis). The explanation of Pulse sequences are defined in a basic way by the article “MRI Physics: pulse sequences” as ‘the pulse sequences define the manner in which the radiofrequency pulses, which generate the detectable signals, and magnetic field gradients, which provide the spatial encoding of the signals’ (Sharma). When the pulse sequences are used a sequence diagram is used to show how the sequences will occur during the MRI.

There are many different sequences available; each used for creating certain images, the most commonly used is the spin echo sequence. When magnetic fields are produced, it means an electron has moved along a wire creating a magnetic field around that electron. When the wire is in the form of a loop, or multiple loops in this case, a very large magnetic field is produced and it runs perpendicular to the field. The magnets within the MRI are known as the primary magnet and the gradient magnets. The primary magnet or permanent magnet is the coiled wire that creates the magnetic field.

These coils have to be stored at -450( Fahrenheit within a type of liquid helium. These magnetic fields are between 10,000 and 30,000 times stronger than the magnetic field of Earth. The gradient magnets consist of three smaller magnets within the MRI machine. These magnets are about 1/1000 as strong as the primary magnet and allow smaller images of the area to be produced. These magnets help focus on a particular part of the body (Cluett). There are many other physical concepts that I did not discuss used within the MRI machine.

The main concepts are radio waves, resonance, pulse sequences, magnetic fields being produced and magnets. Works Cited Bellis, Mary. “Magnetic Resonance Imaging MRI. ” About. com, Investors. New York Times Company, n. d. Web. 5 June 2012. . Cluett, Jonathan. “MRI: What is a MRI?. ” About. com, Orthopedics. New York Times Company, 15 Aug. 2011. Web. 5 June 2012. . Sharma, Harish, and Jim Lagopoulos. “MRI physics: pulse sequences. ” Acta Neuropsychiatrica 22. 2 (2010): 90. EBSCOhost. Web. 5 June 2012. .

In this lab, my group and I main focus was to find out the acceleration of an object that is dropping while thinking that there are no force acting on it due to gravity. Guess what? Galileo was the first famous philosopher that had experience and observe acceleration due to gravity back in the 1700s. Acceleration is an increase in the rate or speed of something. For instance, in this experiment my job was to measure the value of the acceleration of an object in “free fall”. To be specific a free fall is a falling object that is falling under the sole impact of gravity. A free-falling object has an acceleration of 9.8 m/s/s, downhill.

According to experiment 2, there were two different steel balls that was getting tested. One steel ball was bigger than the other one. First, we used the large steel ball to measure trial 1,2 and 3 with a balance scale, then we used the smaller steel ball for trial 4 and 5. The procedure for both was the same.

The total mass for the big ball had a mass of 28.4 grams while the smaller one had a mass of 16.4 grams. Next, the height was measured from the release mechanism to the target pad. According to the data sheet the height was provided for us. For trial 1, we had to release the ball from the height of 0.75(m), 1.0(m) for the second trail, 1.5(m) for the third and fourth, and 1(m) for the last trial.

Before anything the elapsed time must be on zero while the ball is grip on the release mechanism because I noticed that if the number was different from zero, that means that there’s a bad contact between the ball and the mechanism. To avoid that situation, it is important to tighten the ball with the release mechanism. we had to release the ball four times before calculating the average time of flight. When the ball dropped on the time pad, I had received the time of .390 secs on my next three tries we had acquired an estimation close to the amount of seconds as my first try.

When we calculated the average by adding all the numbers and dividing it by 4. The average time came up to 0.389 secs. This shows that the time of flight wouldn’t change as bad. As we continued the process with the rest of the trails, I notice that the average for the small ball was actually comparable with the big ball. That was really shocking and exciting to me. Once we were finish with the average for 1-5 trial, the most interesting part was finding the calculation for each trial combine.

Now I know you wondering, how would you do that? Well it’s really not difficult. All you have to do is multiply 2 from the height of your measurement than divide it by the total average than multiply the total average number twice to get the average “g” g=2s/t^2. The average came up to 9.8 grams.

Up until about the mid twentieth Century the bulk of production relied on “two traditional procedures of forming and machining (Tlusty, 2000). Forming is the procedure of altering the form of the whole work piece, whereas machining removes merely certain, and desired countries. Whilst these cardinal procedures still form the really anchor of contemporary production, there has besides been the demand for new procedures to be developed.

The traditional procedures, as highlighted above, have a figure of built-in restrictions which limit their application to industry. In the instance of conventional machining procedures, a crisp film editing tool is used to organize a bit from the work by shear distortion. This consequences in the formation of high forces together with the corresponding mechanical energies. Together with this are a figure of extra jobs that can originate. Due to sum of energy required to transport out the operation, a physique up of unwanted heat can happen, which frequently leads to deformation of the work piece and surface snap. In certain instances, the forces introduced by the procedure are highly high and in order to procure the work piece considerable clamping forces are required ; this excessively can take to deformation.

Together with these restrictions, the development of stuffs with belongingss of high strength, high hardness and high stamina has driven the debut of untraditional machining methods. Nontraditional machining (NTM) methods have been developed since World War II in an effort to turn to machining demands which can non be carried out by conventional methods entirely (DeGarmo, Black Kohser, 2003). NTM methods provide the ability to machine:

• Complex geometries
• Components with an first-class surface coating
• Delicate constituents, which otherwise would non defy the clamping forces
• Brittle stuffs or stuffs with really high hardness.

There are four types of untraditional procedures; classified harmonizing to the principle signifier of energy used to consequence stuff remotion. These include: mechanical, electrical, thermic and chemical. One procedure which falls into the mechanical class is scratchy H2O jet (AWJ) film editing, and will be the focal point of this study. First, and prior to discoursing AWJ, the procedure of H2O jet (WJ) film editing will be introduced.

Water Jet Cutting (WJC)

Water jet film editing, which is besides known as waterjet machining and hydrodynamic machining, was foremost developed in 1968, followed by the first commercial system in 1971 (Zhong Han, 2003). Through the usage of a all right, hard-hitting, high-speed watercourse of H2O directed at the work piece (surface), a cut is created, as illustrated in figure 1 below. In order to bring forth the all right watercourse of H2O, a nose with an gap (opening) typically in the order of 0.1 – 0.4mm is used (Groover, 1996). Together with this, runing force per unit areas of around 400MPa and above are used to supply sufficient energy for cutting to be carried out. Furthermore, the fluid of the jet can frequently make 900m/s and the cardinal procedure parametric quantities include: H2O force per unit area, opening diameter, H2O flow rate and the working or ‘standoff ‘ distance between the nose and the work piece.

As the typical film editing force per unit areas as mentioned are required, a hydraulic pump is used to supercharge the fluid. The fluid is so passed through a valve, which regulates the flow rate in order to accomplish the optimal cut. The concluding phase of the fluid is to go through through the nozzle opening and impact the work piece surface from a controlled tallness.

Procedure Parameters

The stuff from which the nose is made is doubtless the most of import parametric quantity in footings of procedure control (as this greatly determines the opening diameter). The nozzle unit comprises of a unstained steel holder, together with a gem; normally sapphire, ruby or diamond. Of these stuffs, diamond lasts the longest but is the most expensive. Recent progresss in the production of man-made sapphire offer this stuff as non merely the most cost effectual solution, but besides due to other advantages excessively.

Man-made sapphire can be machined moderately accurately and besides has a high opposition to have on. The most common causes of nozzle failure are due to sedimentations come ining the fluid watercourse, therefore underscoring the demand for high degrees of filtration of the fluid prior to pressurisation, to cut down nozzle wear. With proper nozzle design a tight, coherent waterjet can be produced and maintained really accurately.

When transporting out the cutting procedure, both the opening diameter and the ‘standoff ‘ distance must be closely monitored to keep a changeless deepness of cut. As the nozzle wears, compensatory alterations in the draw tallness must be made. Although existent draw distances vary from beginning to beginning, distances in the order of millimeters are normal; normally around 0.25 – 3.5mm.

WJC: Advantages and Disadvantages

WJC offers many advantages over conventional machining methods. This machining procedure provides the ability to cut stuffs without firing or oppressing the work piece. Furthermore, no important heat is generated, therefore, deformation is minimised and in some instances, eliminated. Unlike machining or grinding, no dust is produced ensuing in small environmental pollution. Other advantages include minimum material loss and easiness of mechanization when used with numerical control and industrial automatons. Whilst such advantages exist, one of the chief disadvantages to H2O jet film editing is that there are merely a limited figure of stuffs that can be cut economically (MTU, 2009). Although it is possible to cut tool steels utilizing this procedure, the provender rates have to be greatly reduced and therefore the edged clip increased. This, in kernel, consequences in a high cost procedure. Such stuffs that can be cut utilizing the H2O jet procedure include: plastics, fabrics, complexs, floor tiles, rug, leather and composition board.

Abrasive Water Jet Cutting (AWJC)

To allow the film editing of difficult stuffs such as ceramics, metals and glass, together with those softer stuffs, for illustration froth and gum elastic, the WJC procedure requires the add-on of scratchy atoms, therefore organizing the scratchy H2O jet (AWJ) cutting technique. In a similar mode to WJC, the procedure is carried out utilizing a high-pressure, high-speed watercourse of H2O; nevertheless, the discrepancy being that an scratchy stuff is drawn in by a vacuity, which is created by jet watercourse.

Procedure Parameters

As antecedently highlighted, the WJC procedure depends on a figure of parametric quantities. Whilst many of these are movable to the AWJC procedure, there are besides add-ons to reflect the alteration in cutting method. Momber Kovacevic (1998) present a list of such parametric quantities.

Although it is by and large accepted by many writers including JankoviA (2008) that the nose or opening diameter is the cardinal film editing parametric quantity, in the instance of AWJC, the abradant besides has considerable influences on the quality of the cut achieved. A choice of the parametric quantities as listed above has been explored in the subsequent subdivision, followed by an overview of the entire system control in the subdivision thenceforth.

Procedure Parameters: Overview of Observed Influences

The most of import parametric quantity, by far, is the orifice diameter. The deepness of cut is straight relative to the opening diameter ; nevertheless, making an optimal point at big diameters. Although related to pump force per unit area, demoing how the deepness of cut varies with opening diameter.

Another parametric quantity that is closely linked to the opening diameter is the focal point diameter. This component of the cutting equipment determines the strength of the watercourse, therefore holding a direct consequence on the material remotion rate.

The focal point diameter is of import non merely in footings of the volume remotion rate but besides the deepness of cut. The deepness of cut is besides determined by this parametric quantity; diminishing as the focal point diameter additions. The lessening in deepness of cut following an optimal point is realised by Himmelreich (1992) and has been attributed to high grades of turbulency. On the other manus, a peculiarly little focal point diameter gives rise to particle hit and clash, giving an inefficient procedure.

Of the cutting parametric quantities listed, the crossbeam rate can be said to hold the greatest influence on the film editing procedure, followed closely by the draw distance. Both of these parametric quantities are controlled by machine design and therefore are bound by the makers ‘ specification.

A big figure of scratchy stuffs are available for usage in AWJC. Typically these are loosely categorised as either oxides or silicates and there are, in a similar manner to the whole procedure, many parametric quantities that determine the features of an abradant.

Whilst it is hard to state precisely which parametric quantity has the greatest influence on the procedure, it is clear that both the hardness of the stuff together with the atom form and size, need consideration. Typical hardness values vary from 30 HV for Cd up to 200 HV for B carbide (Kriegel Palmour, 1961).

Abrasive Water Jet Cutting: Associated Problems

It is clear from the old subdivision that there are many parametric quantities that have an consequence on the AWJC procedure. If such parametric quantities are non carefully controlled, so the efficiency of the procedure decreases along with the quality of the machined portion. Some of the associated jobs are presented in table 1.

Problem and definition

Parameter(s) affected by

• Consequence on constituent
• Taper. This characteristic arises due to a difference in the breadth of the cut at the top surface and the bottom surface and is given as a ratio (besides flank angle).
• Abrasive mass flow rate
• Focus diameter
• Standoff distance
• Trave rate
• This characteristic determines the dimensional truth of the portion.
• Initial Damage Zone. Abrasive atoms impact the surface at normal angles doing craters and abrasive-wear paths.
• Standoff distance
• Focus diameter (Abrasive atom size – composite stuffs)
• Some fictile distortion can happen.
• Change (debasement) in surface roughness/waviness.
• Trave rate
• Focus diameter/length
• Abrasive mass flow rate
• Abrasive atom size/type
• Surface belongingss of stuff are non as desired.
• Decrease in fatigue life of cut stuff due to check formation.
• Abrasive atom size
• Fatigue life reduced. Onset of stress-corrosion snap.
• Surface indurating due to procedure.
• Abrasive stuff
• Variation of hardness at distance from cut.
• Micro-structural alterations:
• Surface checking
• Phase alterations
• Abrasive-particle fragment implanting
• Delamination in composite stuffs
• Burr formation
• Assorted
• Assorted

Abrasive Water Jet Cutting: Control Methods

To guarantee such issues as those mentioned in table 1 do non happen, accurate control mechanisms must be in topographic point. There are many supervising mechanisms in topographic point today, some of which have been briefly described below. These methods lead to the control of the cutting procedure ; nevertheless, this is non automated in these instances.

Jet-Structure Monitoring – used to command focal point diameter. Diameter of entry to concentrate point monitored to reflect alterations of focal point diameter. Wear rate can be monitored utilizing this method.

Acoustic Sensing – used to supervise overall focal point conditions. System based on the fact that a alteration in the focal point conditions (orifice diameter and concentrate diameter) affects the sound generated by the system.

• Inductive Measurement – used to supervise scratchy H2O jet speed. Method requires magnetic scratchy atoms. Abrasive jet is encircled by two little spirals, which is connected to a detection system. When the atom passes through the spiral, a little electric signal is created and the velocity determined. Figure 11 shows the typical apparatus of equipment, in this instance. Besides, laser systems similar to the above, nevertheless utilizing light pulsations alternatively.
• Material-Removal Visualisation – used to supervise material remotion rate. In a similar mode to Acoustic Sensing, noise of cut is monitored. Frequency of signal indicates type of cut ( inter-granular/trans-granular failure ) and therefore determines the efficiency of the cut.
• Workpiece Reaction Force – used to supervise deepness of incursion and surface topography. Empirical expression that takes into history all input parametric quantities excepting the crossbeam rate. Can go a force-feedback system ; leting parametric quantities to be modified to cut down the force.

The above systems offer a chiefly generic attack to system patterning and supply small or no feedback. Modern control of AWJC makes usage of an intelligent monitoring and control system, which has full feedback capablenesss. Such an illustration by Srinivasu & A ; Babu ( 2008 ) utilises two systems: machine-vision based monitoring and intelligent control. The vision based portion monitors the size of the concentrating nose and the control system, which uses unreal nervous webs, continually modifies each parametric quantity to accomplish the best cut. A full analysis of this system is nevertheless beyond the range of this study.

The applications of AWJC are huge, covering industries such as aerospace, automotive and electronics. It is beyond the range of this study to cover any peculiar country in important item ; nevertheless a few illustrations have been given below. Traditional and perchance even simple procedures have been ignored, and alternatively this study concentrates on a few non-standard applications.

Meat Cuting

One application of AWJ cutting is in the meat processing industry. Harmonizing to Wang Shanmugam (2008), meat film editing is an of import activity and factors such as the cost, the presentation and sliting all need consideration. In this instance, salt is used as an scratchy and really good quality cuts, when compared to conventional film editing and even plain H2O jet film editing, can be achieved.

Crunching Wheel Production

This illustration is slightly different to all other applications of AWJC as in most instances a through cut is desired. Axinte et Al. (2009) present an turning application, whereby crunching wheels are shaped harmonizing to their specification. Whilst this is considered a niche market, the writers conclude that AWJC has non merely the economical but besides proficient advantage for fabrication of this constituent. Assorted determining operations can be carried out.

Polishing of Steel

Another application of AWJC is smoothing, and in peculiar steel. Yan et Al. (2008) describe this application, foregrounding that electrical-discharge machining (EDM) is normally used for mold production. The writers province that EDM typically leaves a brickle recast bed; taking to the application of this smoothing method. When compared to traditional methods, AWJC has a lower scratchy ingestion and recycling is improved. In this illustration the abradant is SiC and to help the procedure is covered in wax. This consequences in a much finer surface coating.

Complexs Processing

There are many applications of AWJC in relation to complexs treating as in some instances traditional single-point film editing procedures can non be used. For illustration, Komanduri (1997) describes that it is non possible to machine SiC whisker-reinforced aluminum oxide with a single-point film editing tool; nevertheless, that it may be possible to determine by crunching. Whilst some complexs can be approached in this manner, rapid tool wear is experienced and therefore the debut of AWJC is a much better method.

Decision

The old subdivision provides a figure of non-standard illustrations where AWJC is being used. Although these give a general overview, AWJC can besides be used for alternate machining procedures, such as: milling, turning, piercing, boring (although non level bottomed holes) and thread film editing (Momber Kovacevic, 1998).

Although such procedures as above can be achieved, in a similar instance to before there are many parametric quantities that need to be monitored. This is possibly a downside to this untraditional method unless modern control methods are introduced. Further disadvantages of the procedure include the fact that degradable stuffs can non be cut and the surface coating of machined constituents relies to a great extent on the procedure. Possibly the most important consideration of using this procedure is the apparatus cost; which can be highly high in certain instances. One other disadvantage is the noise created by this fabrication procedure.

Although, as highlighted above, there are many factors that control the procedure its application to modern industry has grown significantly since its debut in the 1970’s. This has been driven chiefly by technological promotions, therefore leting this procedure to be developed, but besides due to of all time germinating stuffs that serve technology applications of today.

Load cells are detectors which are used to mensurate the degree or force per unit area by change overing the force ( torsion or mass ) into electrical signals and so these signals are displayed by the show unit to demo the degree or force per unit area.

Load cells are besides known as burden transducers.

In dictionary, a burden cell is known as “ weight mensurating device necessary for electronic signal that displays weight in the signifier of figures. ”

Load cells can be classified harmonizing to their operations:

Load cells that utilize liquid force per unit area or air force per unit area.

Load cells that utilize snap.

Load cells that utilize a magnetostriction or piezoelectric consequence.

The strain gage burden cell is the largely used among the all sorts of burden cells.

Therefore, when we say “ burden cell, ” we are largely mentioning to strive gauge burden cells.

Although there are many other measurement devices, such as piezoelectric detectors, magnetostrictive detectors, electrical capacity detector and other detectors.

1.2-Types of Load cells

Strain gage burden cells

Tension burden cells

Pneumatic burden cells

Hydraulic burden cells

Shear Load Cells

Compression Load Cells

Bending Load Cells

Ringing Torsion Load Cells

Pancake Load Cells

Single Point Load Cells

1.3-Strain Gauge Load Cells

This is a type of burden cell which is usage to mensurate the degree of any storage vas.

1.3.1-Working rule

When force per unit area is applied on a music director its length alterations due to which opposition of the music director alterations and relation to the alteration in opposition show unit displays the alteration in degree.

1.3.2-Construction and working

A strain gage is consists of a long length music director which is arranged in zig-zag manner on the flexible membrane which is exposed to the applied force per unit area country. This music director is connected in a wheat rock p as a resistance and when force per unit area or weight is applied on the membrane which is connected to the music director it gets stretched and due to stretching the length of the music director alterations and due to alter in length the opposition of the music director additions.

These are normally four or a multiple of four, are connected into a wheat rock p constellation in order to change over the really little alteration in the opposition into the suited electrical signal.

As these gages are combination of mechanical and electrical constituents so the mechanical parts are located at the site but electrical parts are in the control suites due to their environmental and temperature sensitivenesss. And the wires used for the transmittal of the signals besides have their ain opposition so that opposition besides considered during their building.

The accommodation and arrangement of the strain gage burden cell in the wheat rock p and its working phenomena is shown in the undermentioned diagrams.

Strain gage burden cells are placed at the underside of the vass largely to mensurate the degree of the column or vas.

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Figure

Figure 00205.png

1.3.3-Advantages

Strain gage burden cells are used in automotive industry to look into the structural public presentations of the stuff used in doors, goons, short pantss etc.

Strain gage burden cells can be usage for weighing intents.

Strain gage burden cells can besides be usage for stuff testing in procedure industry besides.

Strain gage burden cells are besides used in tensile trial machines as a major constituent.

Strain gage burden cells truth is 0.07 % of the rated capacity

Strain gage burden cells can be used for both enlargement and compaction.

Strain gage burden cells are less dearly-won so largely used in the industry.

1.3.4-Disadvantages

Strain gage burden cells require uninterrupted electric energy for the production and show of signals.

Strain gage burden cells besides requires an elaboration circuit for the coevals of end product show because the signals produced by the gage itself are of really much low electromotive force about in milli Vs.

Strain gage burden cells can non be used for the force per unit area measuring of extremely reactive or caustic stuffs because they can damage the gage.

Strain gage burden cells can non be used for the measuring of really high force per unit area if the stop usage is of plastic.

1.4-Tension Load Cells

This is another type of burden cell which is besides usage to step to the degree.

1.4.1-Working Principle

It consists of a vibrating wire transducer, fixed in a thick-vessel metallic cylinder, designed to supply a extremely stable and sensitive agencies of supervising tensile tonss in weighing systems, like procedure weighing systems and batch systems.

As the applied burden additions on the burden cells the force on the internal vibrating wire besides increases by altering its tenseness, and therefore the resonating frequence of the vibrating wire. The frequence is measured and relative to the applied weight.

1.4.2-Construction and working

The chief portion of this burden cell is strain gauged stop which is for good secured in the transducer shell. The transducer is fitted with a metallic oculus leting in line connexion to the deliberation system, and a metallic hook, attached to the sensitive stop, provides a agency by which weight is applied in a suspended manner.

The burden cell is vented to the ambiance to extinguish barometric effects for the upper limit or optimal truth. The signal overseas telegram which is attached to the burden cell is connected with the control room where these signals can be monitored.

Figure There are besides some Thermistors placed inside its shell which are used to mensurate the temperature of the working fluid or vas. Degree centigrade: UsersAlY RaZaAppDataLocalMicrosoftWindowsTemporary Internet FilesContent.WordUntitled.png

1.4.3-Advantages

The chief advantage of the tenseness burden cell is that it is extremely sensitive and stable.

As it is a vibrating component wire detector and its end product is frequency so it is non affected by the alteration in the overseas telegram opposition and therefore long signal overseas telegrams are non jobs.

The frequence of the vibrating wire is measured by either the portable read-out box or informations lumberman. So it can give more accurate readings.

The end product signal scopes in the electromotive force from 0 to 5 Vs so there is no elaboration unit required and therefore the cost lessenings.

The rated capacity of the tortuosity burden cell is from 10 kilograms to 15 kilograms.

The truth of the tortuosity burden cells is A±0.1 %

The temperature ranges for the working or operation of the tortuosity burden cells is -20A°C to +80A°C.

Such types of transducers have about zero impetus and have besides really low consequence of temperature on its truth.

1.4.4-Disadvantages

This type of burden cells can non be used for high temperature fluids to happen degree or weight of fluid incorporating column.

This type of burden cells can non besides be used for high capacities or for big armored combat vehicles column or weight measurings.

This type of burden cell is extremely affected by the high temperatures due to its sensitive nature of the detection wire.

1.5-Pneumatic Load Cells

This is another type of burden cells which are usage to mensurate the weight in the industry and these are used for low capacity.

1.5.1-Working Principle

This type of burden cells works on “ the force-balance rule. ”

1.5.2-The Force-Balance Principle

The inertial force produced by a seismal land gesture shifts the mass from its original equilibrium place, and the alteration in place or speed of the mass is so interpreted into an electric signal. This rule is for low scope burden cells.

For long scope burden cells the inertial force is balanced with an electrically generated force so that the mass moves every bit low as possible.

1.5.3-Working of pneumatic burden cell

This sort of burden cells consist of a detection component which is exposed to the site or the vas of which force per unit area or lying unstable weight is to be measured. And in this sort of burden cell the force reassigning medium is air as comparison to the any other fluid in instance of hydraulic burden cell. When force is applied by the lying fluid on the feeling portion of the burden cell it transfers this force to the inside air and so this force is applied on the potentiometer which is placed in the wheat rock p. As the force is applied on the feeling portion of the burden cell the opposition of the variable opposition potentiometer alterations due to this force and therefore the possible equilibrium between the oppositions is disturbed and this shows the magnitude of the applied force on the feeling component by exposing it on the show unit.

Figure pneumatic.gif

Another technique which is largely used in such sort of burden cells is the use of the piezoelectric crystals. In this sort the detection component transportations applied force to the interior fluid ( air ) and it imparts this force on the crystal. And due to the application of the applied force on the crystal by agencies of air its construction gets disturbed and due to disturbance in the construction the possible across the crystal alterations and this alteration in the possible across the crystal is detected by the voltmeter and so this electromotive force is converted into weight of force units and displayed on the exposing unit. Most of the clip wheat rock p is used for this sort of burden cell and there is merely variable resistance largely used while other resistances in the wheat rock p are of fixed opposition.

1.5.4-Advantages

They are largely used on smaller tons when safety and protection are of premier concern.

They are better in truth as comparison to the hydraulic burden cells because there is no alteration in the denseness and truth of the fluid being used for the transportation of applied force.

They besides preferred on the hydraulic burden cells because there is no usage of liquid in these sorts of burden cells.

These types of burden cells are inherently explosion cogent evidence and insensitive to temperature fluctuations.

As they contain no fluids so there is no job of taint of the procedure if the stop gets ruptured.

Pneumatic burden cells are besides used to mensurate little weights that depend upon cleanliness and safety.

1.5.5-Disadvantages

The chief disadvantage of these types of burden cells is that they can non be used for high measure measuring.

Although they are really resistive to the temperature effects but their truth even acquire disturbed at really high temperature.

1.6-Hydraulic Load Cells

This is another type of burden cells which are used to mensurate the magnitude of the applied force and their transition to the electric signals and its digital show.

1.6.1-Working Principle

This type of burden cells besides work on “ the force-balance rule. ”

The difference between the pneumatic burden cell and hydraulic burden cell is merely the transferring medium. In instance of pneumatic burden cell the force reassigning medium is air while in hydraulic burden cells the force reassigning medium is largely liquid or incompressible oil which is besides known as break oil.

1.6.2-Construction and working

Hydraulic burden cell consists of a fluid which act as a force reassigning medium and a piezoelectric crystal which is usage to change over this applied force into possible difference and so there is an agreement for the transition of this possible difference in footings of weight or force per unit area. There is a stop which is usage to feel the force exerted from the external side and the whole shell in which this complete cell is enclosed.

When the force per unit area or weight by the vas or column is applied on the stop of the burden cell it sense that force and so transportations this force to the fluid which is filled in the shell of this burden cell. Then this force is transferred to the piezoelectric crystal by the fluid or oil and this oil transfers this force by the Pascal ‘s jurisprudence. So when the force is transferred by the oil it disturbs the internal construction of the piezoelectric crystal and due to this alteration in the construction of the piezoelectric crystal a possible difference is generated across the piezoelectric crystal. This possible difference is detected by the electric sensor and electric signal is transferred to the show unit to expose the magnitude of the applied force, weight or force per unit area.

Figure Hydraulic.gif

1.6.3-Advantages

These are largely use to happen the weight of the stuff in the storage armored combat vehicles, bin or hopper.

The end product given by these types of burden cells is additive and largely unaffected by the sum of the filling fluid ( oil ) or by its temperature.

If the hydraulic burden cells have been decently installed and calibrated so truth is largely within 0.25 % full graduated table or better and this is acceptable for most procedure weighing applications.

As these types of burden cells have no electrical constituents therefore it is ideal for usage in risky or caustic countries.

For more accurate measuring, the weight of the armored combat vehicle should be obtained by turn uping a burden cell at different points and summing their end products.

1.6.4-Disadvantages

One disadvantage of this type of burden cell is that the elastomeric stop limits the maximal force that can be applied on the Piston or stop to about 1,000 psig.

Electronic pari-mutuel machine is required in instance of acquiring more accurate reading by summing the readings of the single burden cells.

Another disadvantage of hydraulic burden cell is that they are expensive and are complex to utilize.

1.7-Shear Load Cells

This is another type of burden cells which is usage to mensurate the weight or the degree of the column incorporating fluid or some stuff.

1.7.1-Working Principle

This type of burden cells works on the shear of the web. A web of an elastic stuff is inserted at some degree in the vas or storage armored combat vehicle and a shear emphasis exerted by the unstable column stretches the web harmonizing to the burden of the unstable column. Therefore by mensurating the shear emphasis the degree or weight of the fluid in a column can be measured.

1.7.2-Construction and working

This type of burden cells consists of a web and a frame which is movable and the web is fixed with this frame. There are strain gages which are straight connected with this web and step the weight or degree of the column by mensurating the shear emphasis exerted by the liquid nowadays in the column on the web. As the web is inserted in the liquid column, liquid exerts the force on this web as this web is stretchy and elastic so it gets stretched and this stretched province of the web is sensed by the strain gages. This web is inserted in the liquid column perpendicular to the axis of the column. Then strain gages transfers the mensural value of the shear emphasis exerted by the tallness of the liquid column to the electrical transducers which converts it into electrical signals and so transmits it to the show unit to expose the mensural value of the weight in footings of degree or force per unit area as we required.

Figure

1.7.3-Advantages

Shear burden cells are popular now for all type of mediums and for high capacities.

Shear-web is non limited to merely beam constellations.

Shear-web detection component is besides being used by high capacity BSP and USP in a more complex manner.

Shear burden cell engineering is besides being used in rearward transducers.

Shear tonss cells can readily be sealed and can be protected from the environmental effects.

1.7.4-Disadvantages

Shear burden cells have comparatively little sensitiveness at the burden point so can non be used for little graduated table measurings.

Shear burden cells are expensive as comparison to the strain gages.

Shear burden cells are delicate merely because of the web which is really delicate and can be easy damage due to overload fro few minutes even.