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SEMINAR TOPICS CATEGORY

Mechanical Topics Category

Computer Aided Process Planning (CAPP)

Added on: February 13th, 2020 by Afsal Meerankutty No Comments

Technological advances are reshaping the face of manufacturing, creating paperless manufacturing environments in which computer automated process planning (CAPP) will play a preeminent role. The two reasons for this effect are: Costs are declining, which encourages partnerships between CAD and CAPP developers and access to manufacturing data is becoming easier to accomplish in multivendor environments. This is primarily due to increasing use of LANs; IGES and the like are facilitating transfer of data from one point to another on the network; and relational databases (RDBs) and associated structured query language (SQL) allow distributed data processing and data access.
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With the introduction of computers in design and manufacturing, the process planning part needed to be automated. The shop trained people who were familiar with the details of machining and other processes were gradually retiring and these people would be unavailable in the future to do process planning. An alternative way of accomplishing this function was needed and Computer Aided Process Planning (CAPP) was the alternative. Computer aided process planning was usually considered to be a part of computer aided manufacturing. However computer aided manufacturing was a stand alone system. Infact a synergy results when CAM is combined with CAD to create a CAD/CAM. In such a system CAPP becomes the direct connection between design and manufacturing.

Moreover, the reliable knowledge based computer-aided process planning application MetCAPP software looks for the least costly plan capable of producing the design and continuously generates and evaluates the plans until it is evident that non of the remaining plans will be any better than the best one seen so far. The goal is to find a useful reliable solution to a real manufacturing problem in a safer environment. If alternate plans exist, rating including safer conditions is used to select the best plans

Air Muscles

Added on: February 10th, 2020 by Afsal Meerankutty No Comments

Air muscle is essentially a robotic actuator which is replacing the conventional pneumatic cylinders at a rapid pace. Due to their low production costs and very high power to weight ratio, as high as 400:1, the preference for Air Muscles is increasing. Air Muscles find huge applications in biorobotics and development of fully functional prosthetic limbs, having superior controlling as well as functional capabilities compared with the current models. This paper discusses Air Muscles in general, their construction, and principle of operation, operational characteristics and applications.

Robotic actuators conventionally are pneumatic or hydraulic devices. They have many inherent disadvantages like low operational flexibility, high safety requirements, and high cost operational as well as constructional etc. The search for an actuator which would satisfy all these requirements ended in Air Muscles. They are easy to manufacture, low cost and can be integrated with human operations without any large scale safety requirements. Further more they offer extremely high power to weight ratio of about 400:1. As a comparison electric motors only offer a power ration of 16:1. Air Muscles are also called McKibben actuators named after the researcher who developed it.

Green Engine

Added on: February 6th, 2020 by Afsal Meerankutty No Comments

Everyday radios, newspapers, televisions and the internet warn us of energy exhaustion, atmospheric pollution and hostile climatic conditions. After few hundred years of industrial development, we are facing these global problems while at the same time we maintain a high standard of living. The most important problem we are faced with is whether we should continue “developing” or “die”.

Coal, petroleum, natural gas, water and nuclear energy are the five main energy sources that have played important roles and have been widely used by human beings.

The United Nations Energy Organization names all of them “elementary energies”, as well as “conventional energies”. Electricity is merely a “second energy” derived from these sources. At present, the energy consumed all over the world almost completely relies on the supply of the five main energy sources. The consumption of petroleum constitutes approximately 60 percent of energy used from all sources, so it is the major consumer of energy.

The green engine is one of the most interesting discoveries of the new millennium. It has got some unique features that were used for the first time in the making of engines. This engine is a piston less one with features like sequential variable compression ratio, direct air intake, direct fuel injection, multi-fuel usage etc. The efficiency of this engine is high when compared to the contemporary engines and also the exhaust emissions are near zero. The significance of the engine lies in the efficiency when the present world conditions of limited resources of energy are considered. Prototypes of the engine have been developed. Generators have been produced with the green engine.

Steam Turbine

Added on: January 28th, 2020 by Afsal Meerankutty No Comments

A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Sir Charles Parsons in 1884.
Definitions of steam turbine:

  • Turbine in which steam strikes blades and makes them turn
  • A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Sir Charles Parsons in 1884.
  • A system of angled and shaped blades arranged on a rotor through which steam is passed to generate rotational energy. Today, normally used in power stations
  • A device for converting energy of high-pressure steam (produced in a boiler) into mechanical power which can then be used to generate electricity.
  • Equipment unit flown through by steam, used to convert the energy of the steam into rotational energy.

A machine for generating mechanical power in rotary motion from the energy of steam at temperature and pressure above that of an available sink. By far the most widely used and most powerful turbines are those driven by steam. Until the 1960s essentially all steam used in turbine cycles was raised in boilers burning fossil fuels (coal, oil, and gas) or, in minor quantities, certain waste products. However, modern turbine technology includes nuclear steam plants as well as production of steam supplies from other sources.

The illustration shows a small, simple mechanical-drive turbine of a few horsepower. It illustrates the essential parts for all steam turbines regardless of rating or complexity: (1) a casing, or shell, usually divided at the horizontal center line, with the halves bolted together for ease of assembly and disassembly; it contains the stationary blade system; (2) a rotor carrying the moving buckets (blades or vanes) either on wheels or drums, with bearing journals on the ends of the rotor; (3) a set of bearings attached to the casing to support the shaft; (4) a governor and valve system for regulating the speed and power of the turbine by controlling the steam flow, and an oil system for lubrication of the bearings and, on all but the smallest machines, for operating the control valves by a relay system connected with the governor; (5) a coupling to connect with the driven machine; and (6) pipe connections to the steam supply at the inlet and to an exhaust system at the outlet of the casing or shell.Steam turbines are ideal prime movers for driving machines requiring rotational mechanical input power. They can deliver constant or variable speed and are capable of close speed control. Drive applications include centrifugal pumps, compressors, ship propellers, and, most important, electric generators.

Navbelt and Guidecane

Added on: January 27th, 2020 by Afsal Meerankutty No Comments

 Recent revolutionary achievements in robotics and bioengineering have given scientists and engineers great opportunities and challenges to serve humanity. This seminar is about “NAVBELT AND GUIDECANE”, which are two computerised devices based on advanced mobile robotic navigation for obstacle avoidance useful for visually impaired people. This is “Bioengineering for people with disabilities”. NavBelt is worn by the user like a belt and is equipped with an array of ultrasonic sensors. It provides acoustic signals via a set of stereo earphones that guide the user around obstacles or displace a virtual acoustic panoramic image of the traveller’s surroundings. One limitation of the NavBelt is that it is exceedingly difficult for the user to comprehend the guidance signals in time, to allow fast work. A newer device, called GuideCane, effectively overcomes this problem. The GuideCane uses the same mobile robotics technology as the NavBelt but is a wheeled device pushed ahead of the user via an attached cane. When the Guide Cane detects an obstacle, it steers around it. The user immediately feels this steering action and can follow the Guide Cane’s new path easily without any conscious effort. The mechanical, electrical and software components, user machine interface and the prototypes of the two devices are described below.

Brushless DC Electric Motor

Added on: January 25th, 2020 by Afsal Meerankutty No Comments

A microprocessor-controlled BLDC motor powering a micro remote-controlled airplane. This external rotor motor weighs 5 grams, consumes approximately 11 watts (15 millihorsepower) and produces thrust of more than twice the weight of the plane.
Brushless DC motors (BLDC motors, BL motors) also known as electronically commutated motors (ECMs, EC motors) are synchronous electric motors powered by direct-current (DC) electricity and having electronic commutation systems, rather than mechanical commutators and brushes. The current-to-torque and voltage-to-speed relationships of BLDC motors are linear.
BLDC motors may be described as stepper motors, with fixed permanent magnets and possibly more poles on the stator than the rotor, or reluctance motors. The latter may be without permanent magnets, just poles that are induced on the rotor then pulled into alignment by timed stator windings. However, the term stepper motor tends to be used for motors that are designed specifically to be operated in a mode where they are frequently stopped with the rotor in a defined angular position; this page describes more general BLDC motor principles, though there is overlap.

Superconducting Rotating Machine

Added on: January 25th, 2020 by Afsal Meerankutty No Comments

Advances in High Temperature Superconductors (HTS) are enabling a new class of synchronous rotating machines (SuperMotors and SuperGenerators) that can generically be categorized as SuperMachines. Compared to conventional machines of equivalent rating, these SuperMachines are expected to be less expensive, lighter, more
compact, efficient, and provide significantly superior stable operation in a power system. The field windings are made with HTS conductor material (BSCCO, or Bi-2223) which operates at 35-40 K and can be cooled with inexpensive, off-the-shelf cryocoolers available from a number of manufacturers throughout the world. As will be discussed, these advanced SuperMachines are attractive for use in industrial as well as naval and commercial maritime industry applications. This paper discusses recent SuperMachine work at AMSC and other companies. HTS rotating machine technology is maturing rapidly, and electricity producers as well as the end-users will undoubtedly benefit enormously from these advancements.

Methanol Fueled Marine Diesel Engine

Added on: January 19th, 2017 by Afsal Meerankutty No Comments

Nowadays concerns about methanol have increased from the viewpoints of environmental protection and versatility of fuels at a global scale. Energetic research on methanol-fueled automobile engines has been forwarded from the viewpoints of low environmental pollution and the use of alternate fuel since the oil crisis, and they are now being tested on vehicles in various countries in the world. Desire for saving of maintenance cost and labour prevails as well as the environmental problems in the field of marine engines. From these motives scientists have carried out research and development of a methanol fueled marine diesel engine which is quite different from automobile engines in the size, main particulars, working condition and durability.

Although scientists have made a great use of invaluable knowledge from automotive technology, some special studies were necessary due to these differences. Ignition method is a typical one. Dual fuel injection system was tried for trouble-free ignition of methanol fuel. This system is thought to be the most favourable ignition method for marine diesel engines which have to withstand quick load change and accept no misfiring. 

Overall Equipment Effectiveness

Added on: January 11th, 2017 by Afsal Meerankutty No Comments

In today’s economy, you’re expected to continuously improve your Return on Total Capital. And as capital to build new, more efficient plants becomes more difficult to obtain, you often have to meet growing production demands with current equipment and facilities — while continuing to cut costs.

There are several ways you can optimize your processes to improve profitability. But it can be difficult to understand the overall effectiveness of a complex operation so you can decide where to make improvements. That’s especially true when the process involves multiple pieces of equipment that affect each other’s effectiveness.

One metric that can help you meet this challenge is Overall Equipment Effectiveness, or OEE. OEE measures the health and reliability of a process relative to the desired operating level. It can show you how well you’re utilizing resources, including equipment and labor, to satisfy customers by matching product quality and supply requirements.

Overall Equipment Effectiveness (OEE) measures total performance by relating the availability of a process to its productivity and output quality.

OEE addresses all losses caused by the equipment, including
• Not being available when needed because of breakdowns or set-up and adjustment losses
• Not running at the optimum rate because of reduced speed or idling and minor stoppage losses
• Not producing first-pass A1 quality output because of defects and rework or start-up losses.

OEE was first used by Seiichi Nakajima, the founder of total productive maintenance (TPM), in describing a fundamental measure for tracking production performance. He challenged the complacent view of effectiveness by focusing not simply on keeping equipment running smoothly, but on creating a sense of joint responsibility between operators and maintenance workers to extend and optimize overall equipment performance.

First applied in discrete manufacturing, OEE is now used throughout process, batch, and discrete production plants.

Cryogenic Grinding

Added on: October 9th, 2013 by 1 Comment

Cryogenic grinding, also known as freezer milling, freezer grinding, and cryomilling, is the act of cooling or chilling a material and then reducing it into a small particle size. For example, thermoplastics are difficult to grind to small particle sizes at ambient temperatures because they soften, adhere in lumpy masses and clog screens. When chilled by dry ice, liquid carbon dioxide or liquid nitrogen, the thermoplastics can be finely ground to powders suitable for electrostatic spraying and other powder processes. Cryogenic grinding of plant and animal tissue is a technique used by microbiologists. Samples that require extraction of nucleic acids must be kept at ?80 °C or lower during the entire extraction process. For samples that are soft or flexible at room temperature, cryogenic grinding may be the only viable technique for processing samples. A number of recent studies report on the processing and behavior of nanostructured materials via cryomilling.

Thermo Acoustic Refrigeration

Added on: October 7th, 2013 by 2 Comments

Thermo acoustic have been known for over years but the use of this phenomenon to develop engines and pumps is fairly recent. Thermo acoustic refrigeration is one such phenomenon that uses high intensity sound waves in a pressurized gas tube to pump heat from one place to other to produce refrigeration effect. In this type of refrigeration all sorts of conventional refrigerants are eliminated and sound waves take their place. All we need is a loud speaker and an acoustically insulated tube. Also this system completely eliminates the need for lubricants and results in 40% less energy consumption. Thermo acoustic heat engines have the advantage of operating with inert gases and with little or no moving parts, making them highly efficient ideal candidate for environmentally-safe refrigeration with almost zero maintenance cost. Now we will look into a thermo acoustic refrigerator, its principle and functions.

Cruise Missile Technology

Added on: September 26th, 2013 by 2 Comments

A cruise missile is basically a small, pilotless airplane. Cruise missiles have an 8.5-foot (2.61-meter) wingspan, are powered by turbofan engines and can fly 500 to 1,000 miles (805 to 1,610 km) depending on the configuration. A cruise missile’s job in life is to deliver a 1,000-pound (450-kg) high-explosive bomb to a precise location — the target.
Cruise missiles come in a number of variations and can be launched from submarines, destroyers or aircraft. Cruise missiles generally consist of a guidance system, payload, and propulsion system, housed in an airframe with small wings and empennage for flight control. Payloads usually consist of a conventional warhead or a nuclear warhead. Cruise missiles tend to be propelled by a jet engine, turbofan engines being preferred due to their greater efficiency at low altitude. Cruise missiles are designed to deliver a large warhead over long distances with high accuracy. Modern cruise missiles can travel at supersonic or high subsonic speeds, are self-navigating, and can fly on a non-ballistic, extremely low altitude trajectory. They are distinct from unmanned aerial vehicles (UAV) in that they are used only as weapons and not for reconnaissance. In a cruise missile, the warhead is integrated into the vehicle and the vehicle is always sacrificed in the mission.

Axial-Field Electrical Machines

Added on: September 25th, 2013 by 2 Comments

Axial-field electrical machines offer an alternative to the conventional machines. In the axial-field machine, the air gap flux is axial in direction and the active current carrying conductors are radially positioned. This paper presents the design characteristics, special features, manufacturing aspects and potential applications for axial-field electrical machines. The experimental from several prototypes, including d.c. machines, synchronous machines and single-phase machines are given. The special features of the axial-field machine, such as its planar and adjustable air gap, flat shape, ease of diversification, etc., enable axial-fled machines to have distinct advantages over conventional machines in certain applications, especially in special purpose applications. conventional radial field machines. The axial field electrical machines described in this paper are particularly suitable for d.c and synchronous machines where the double air gaps present no difficulties since these machines normally require fairly large air gaps to reduce the effect of armature reaction. One of the major objections to the use of AFMs lies in the difficulty on cutting the slots in their laminated cores.

Intelligent Cooling System

Added on: March 25th, 2012 by 3 Comments

In the present paper, efforts have been made to highlight the concept of an “INTELLIGENT COOLING SYSTEM”. The basic principle behind this is to control the flow rate of coolant by regulating the valve by implementing FUZZY LOGIC.

In conventional process the flow rate is constant over the entire engine jacket. This induces thermal stresses & reduction in efficiency.

The “INTELLIGENT COOLING SYSTEM” i.e implementation of fuzzy logic will overcome the above stated drawbacks in any crisp situation. The flow rate of coolant will be controlled by control unit & intelligent sensors.

This is a concept and an innovative idea not been implemented yet.

Pneumatic Control System

Added on: March 24th, 2012 by No Comments

Control system utilize pressure differential created by gas source to drive the transfer of material. Pneumatic control system are all about using compressed air to operate and power a system air taken from the atmosphere and squeezed are compressed .This compressed air is then used a pneumatic system to do work . Pneumatic system are used in Meany field such as lorry brake, bicycle tyres, car tyres, paint spraying aircraft and hydraulic system In this paper, we propose an intelligent control method for a pneumatic servo nonlinear system with static friction. The real machine experiment confirmed the improvement of the speed of response and the stop accuracy and the effectiveness of the proposed method.

Pulse Detonation Engine

Added on: March 24th, 2012 by No Comments

Rocket engines that work much like an automobile engine are being developed at NASA’s Marshall Space Flight Center in Huntsville, Ala. Pulse detonation rocket engines offer a lightweight, low-cost alternative for space transportation. Pulse detonation rocket engine technology is being developed for upper stages that boost satellites to higher orbits. The advanced propulsion technology could also be used for lunar and planetary Landers and excursion vehicles that require throttle control for gentle landings.

The engine operates on pulses, so controllers could dial in the frequency of the detonation in the “digital” engine to determine thrust. Pulse detonation rocket engines operate by injecting propellants into long cylinders that are open on one end and closed on the other. When gas fills a cylinder, an igniter—such as a spark plug—is activated. Fuel begins to burn and rapidly transitions to a detonation, or powered shock. The shock wave travels through the cylinder at 10 times the speed of sound, so combustion is completed before the gas has time to expand. The explosive pressure of the detonation pushes the exhaust out the open end of the cylinder, providing thrust to the vehicle.
A major advantage is that pulse detonation rocket engines boost the fuel and oxidizer to extremely high pressure without a turbo pump—an expensive part of conventional rocket engines. In a typical rocket engine, complex turbo pumps must push fuel and oxidizer into the engine chamber at an extremely high pressure of about 2,000 pounds per square inch or the fuel is blown back out.

The pulse mode of pulse detonation rocket engines allows the fuel to be injected at a low pressure of about 200 pounds per square inch. Marshall Engineers and industry partners United Technology Research Corp. of Tullahoma, Tenn. and Adroit Systems Inc. of Seattle have built small-scale pulse detonation rocket engines for ground testing. During about two years of laboratory testing, researchers have demonstrated that hydrogen and oxygen can be injected into a chamber and detonated more than 100 times per second.

NASA and its industry partners have also proven that a pulse detonation rocket engine can provide thrust in the vacuum of space. Technology development now focuses on determining how to ignite the engine in space, proving that sufficient amounts of fuel can flow through the cylinder to provide superior engine performance, and developing computer code and standards to reliably design and predict performance of the new breed of engines.
A developmental, flight-like engine could be ready for demonstration by 2005 and a full-scale, operational engine could be finished about four years later. Manufacturing pulse detonation rocket engines is simple and inexpensive. Engine valves, for instance, would likely be a sophisticated version of automobile fuel injectors. Pulse detonation rocket engine technology is one of many propulsion alternatives being developed by the Marshall Center’s Advanced Space Transportation Program to dramatically reduce the cost of space transportation.

Humanoid Robot

Added on: March 23rd, 2012 by 4 Comments

The field of humanoids robotics is widely recognized as the current challenge for robotics research .The humanoid research is an approach to understand and realize the complex real world interactions between a robot, an environment, and a human. The humanoid robotics motivates social interactions such as gesture communication or co-operative tasks in the same context as the physical dynamics. This is essential for three-term interaction, which aims at fusing physical and social interaction at fundamental levels.

People naturally express themselves through facial gestures and expressions. Our goal is to build a facial gesture human-computer interface fro use in robot applications. This system does not require special illumination or facial make-up. By using multiple Kalman filters we accurately predict and robustly track facial features. Since we reliably track the face in real-time we are also able to recognize motion gestures of the face. Our system can recognize a large set of gestures (13) ranging from “yes”, ”no” and “may be” to detecting winks, blinks and sleeping.

Geothermal Energy

Added on: March 21st, 2012 by No Comments

The word geothermal comes from the Greek words geo (earth) and therme ( heat). So, geothermal energy is heat from within the earth. We can use the steam and hot water produced inside the earth to heat buildings or generate electricity. Geothermal energy is a renewable energy source because the water is replenished by rainfall and the heat is continuously produced in the earth.

Historically , the first application of geothermal energy were for space heating , cooking and medical purposes . The earliest record of space heating dates back to 1300 in Iceland .In the early 1800s , geothermal energy was used on what was then a large scale by the conte Franceso de Laderel to recover boric acid . The first mechanical conversion was in 1897 when the steam of the field at Larderallo, Italy , was used to heat a boiler producing steam which drove a small steam engine . The first attempt to produce electricity also took place at Larderello in 1904 with an electricity generator that powered four light bulbs . This was followed in 1912 by a condensating turbine ; and by 1914, 8.5 MW of electricity was being produced . By 1944 larderello was producing 127MW. The Plant was destroyed near end of World war 2, but was fortunately rebuilt and expanded evevtually reached 360 MW in 1981.

Surface Plasmon Resonance

Added on: March 20th, 2012 by No Comments

Surface plasmon resonance (SPR) is a phenomenon occurring at metal surfaces(typically gold and silver) when an incident light beam strikes the surface at a particular angle. Depending on the thickness of a molecular layer at the metal surface, the SPR phenomenon results in a graded reduction in intensity of the reflected light. Biomedical applications take advantage of the exquisite sensitivity of SPR to the refractive index of the medium next to the metal surface, which makes it possible to measure accurately the adsorption of molecules on the metal surface an their eventual interactions with specific ligands. The last ten years have seen a tremendous development of SPR use in biomedical applications.

The technique is applied not only to the measurement in real time of the kinetics of ligands receptor interactions and to the screening of lead compounds in the pharmaceutical industry, but also to the measurement DNA hybridization, enzyme- substrate interactions, in polyclonal antibody characterization, epitope mapping, protein conformation studies and label free immunoassays. Conventional SPR is applied in specialized biosensing instruments. These instruments use expensive sensor chips of limited reuse capacity and require complex chemistry for ligand or protein immobilization. Laboratory has successfully applied SPR with colloidal gold particles in buffered solutions. This application offers many advantages over conventional SPR. The support is cheap, easily synthesized, and can be coated with various proteins or protein ligand complexes by charge adsorption. With colloidal gold, the SPR phenomenon can be monitored in any UV spectrophotometer. For high throughput applications we have adapted the technology in an automated clinical chemistry analyzer. This simple technology finds application in label free quantitative immunoassay techniques for proteins and small analytes, in conformational studies with proteins as well as real time association dissociation measurements of receptor ligand interactions for high throughput screening and lead optimization.

Dynamic Speed Governor

Added on: March 19th, 2012 by 2 Comments

The Dynamic Speed Governor is a system that can be implemented effectively for an efficient and perfectly controlled traffic system. This system can limit the speed of a moving vehicle over an area where the speed has to be restricted and retained within a predetermined value. The Dynamic Speed Governor consists of mainly two parts, the Transmitter section and the Receiver section. The transmitter section is mounted on the signal board, on which the speed limit over that area is indicated. Receiver section is kept inside the vehicle. The radio frequency signal from the transmitter is transmitted and the receiver receives it. If the speed of the vehicle is greater than the speed limit proposed for that particular area, which in turn is transmitted by the transmitter section, the speed governor comes into action and restricts the driver from going beyond that rated speed. If the system detects that the speed of the vehicle has gone beyond the speed limit, a signal is generated from the dynamic speed governor circuit. This signal in turn is used to drive the mechanical part of the vehicle, which closes the fuel nozzle of the vehicle thereby restricting the vehicle from going beyond that speed. In this particular reproduction of the system, to indicate the signal produced, the signal output from the circuit is used to trigger a mono-stable multi-vibrator, which in turn sounds a buzzer.

Magneto Abrasive Flow Machining

Added on: March 18th, 2012 by No Comments

Magneto abrasive flow machining (MAFM) is a new technique in machining. The orbital flow machining process has been recently claimed to be another improvement over AFM, which performs three-dimensional machining of complex components. These processes can be classified as hybrid machining processes (HMP)—a recent concept in the advancement of non-conventional machining. The reasons for developing a hybrid machining process is to make use of combined or mutually enhanced advantages and to avoid or reduce some of the adverse effects the constituent processes produce when they are individually applied. In almost all non-conventional machining processes such as electric discharge machining, electrochemical machining, laser beam machining, etc., low material removal rate is considered a general problem and attempts are continuing to develop techniques to overcome it. The present paper reports the preliminary results of an on-going research project being conducted with the aim of exploring techniques for improving material removal (MR) in AFM. One such technique studied uses a magnetic field around the work piece. Magnetic fields have been successfully exploited in the past, such as machining force in magnetic abrasive finishing (MAF), used for micro machining and finishing of components, particularly circular tubes. The process under investigation is the combination of AFM and MAF, and is given the name Magneto Abrasive Flow Machining (MAFM).

Drive-By-Wire Systems

Added on: March 17th, 2012 by No Comments

The idea of ‘X-by-wire’, the control of a car’s vital functions like steering and breaks by electrical rather than mechanical links, it tantalizing to some and terrifying to other.

Aircraft may have been equipped with Fly-by-wire system for years, but do we really feel comfortable at the idea of computer sitting between ourselves and steering and breaks of our car?

What might, however, at first sound alarming actually has many benefits and whatever we as costumers may think, X-by-wire is already emerging fast. Electronic throttles, the Mercedes sensotronic break controls (SBC) and now BMW’s active front steering (ABS) in the new launches are all examples of drive-by-wire technologies.

  • Mercedes-Benz’s cutting edge sensotronic break control technology, used in new SL, delivers more breaking movement in an emergency and helps stabilize skid early.
  • Delphi’s X-by –wire is a family of advanced breaking, steering, throttle and suspension control system which function without conventional mechanical component.
  • GM’s hydrogen-power X-by-wire concept uses electrical signals instead of mechanical linkages or hydraulics to operate the motor, breaks and steering function.

Highly organized network of wired, sensors, controllers and actuators control the mechanical function of the vehicle’s steering, breaking, throttle and suspension control system.

Strain Guage

Added on: March 15th, 2012 by No Comments

A strain gauge (also strain gage) is a device used to measure the strain of an object. Invented by Edward E. Simmons and Arthur C. Ruge in 1938, the most common type of strain gauge consists of an insulating flexible backing which supports a metallic foil pattern. The gauge is attached to the object by a suitable adhesive, such as cyanoacrylate. As the object is deformed, the foil is deformed, causing its electrical resistance to change. This resistance change, usually measured using a Wheatstone bridge, is related to the strain by the quantity known as the gauge factor.

Plastic Welding

Added on: March 14th, 2012 by 2 Comments

Plastic welding and spot welding – both are almost similar to each other. There is a difference noted. In plastic welding, heat is supplied through convection of the pincher tips, instead of conduction. The two plastic pieces are brought together. At the time of welding, a jet of hot air is liberated. This melts the parts to be joined along with the plastic filler rod. As the rod starts melting, it is forced into the joint and causes the fusion of the parts.

Plastic identification is the first point to be noted in order to choose a suitable plastic welding rod. A plastic welding rod or thermoplastic welding rod is of a constant cross-section shape. Using this, two plastic pieces can be joined. It may have a circular or triangular cross-section. Porosity of the plastic welding rod is an important factor. Air bubbles in the rod will be created due to its high porosity. This is responsible for decreasing the quality of the welding. So, the rods used must maintain zero porosity. Otherwise, they should be void less. Products like chemical tanks, water tanks, heat exchangers and plumbing fittings are manufactured by using the technique of plastic welding. By adopting this technique, money can be saved.

Using plastic welding, two plastics can be welded together. This type of weld is performed on children’s toys, lawn furniture, auto parts and other plastic equipments which are used daily – both for domestic and commercial purposes. In order to join the thermoplastics, when they are heated an under a particular pressure, this type of welding is employed. In normal practice, using filler material, the pieces are joined together. There are certain occasions wherein filler material can be avoided. Generally, plastic is not durable and has a shorter life span. Natural elements like cold weather, ultraviolet radiation from the sun or continuous exposure to chemicals causing contamination, will create damage to plastic products. Plastic can be subjected to damage if it is hit on a hard surface. But, as the price of new parts is high, it is preferred to repair the existing products.

As there are different types of plastics, we must know which one we are working with in order to find the exact welding material to be used. We must know the difference between thermoplastics and thermo sets because it is not possible to weld thermo sets. If you use the wrong welding rod for the plastic to be repaired, bonding will not take place. As materials like polyolefin’s have a lower surface energy, a special group of polyolefin adhesives has to be used. When you are repairing plastic, there are usually two types of defects – a crack or a broken part. In the case of a crack, there is a particular stress affecting the inside of the material. You have to repair the crack and you should not continue through the piece.

Design, Analysis, Fabrication and Testing of Composite Leaf Spring

Added on: March 11th, 2012 by No Comments

The subject gives a brief look on the suitability of composite leaf spring on vehicles and their advantages. Efforts have been made to reduce the cost of composite leaf spring to that of steel leaf spring. The achievement of weight reduction with adequate improvement of mechanical properties has made composite a very replacement material for convectional steel. Material and manufacturing process are selected upon on the cost and strength factor. The design method is selected on the basis of mass production.
From the comparative study, it is seen that the composite leaf spring are higher and more economical than convectional leaf spring.

Biodiesel

Added on: March 11th, 2012 by 1 Comment

There is growing interest in biodiesel (fatty acid methyl ester or FAME) because of the similarity in its properties when compared to those of diesel fuels. Diesel engines operated on biodiesel have lower emissions of carbon monoxide, unburned hydrocarbons, particulate matter, and air toxics than when operated on petroleum-based diesel fuel. Production of fatty acid methyl ester (FAME) from rapeseed (non edible oil) fatty acid distillate having high free fatty acids (FFA) was investigated in this work. Conditions for transesterification process of rapeseed oil were 1.8 % H2SO4 as catalyst, MeOH/oil of molar ratio 2:0.1 and reaction temperature 65 °C, for a period of 3h. The yield of methyl ester was > 90 % in 1h.

Biodiesel is becoming widely available in most parts of the U.S. and can be substituted for petroleum-based diesel fuel (“petro diesel”) in virtually any standard unmodified diesel engine. Biodiesel offers many advantages over petroleum-based diesel:

  • It is made from domestically produced and renewable agricultural products, mainly vegetable oil or animal fat.
  • It is essentially non-toxic and biodegradable.
  • It has a high flash point (over 300ºF) and is difficult to light on fire with a match.
  • It reduces emissions of many toxic air pollutants.
  • It functions as an excellent fuel lubricant and performs similarly to low-sulfur diesel with regards to power, torque, and fuel consumption.
  • It can greatly reduce carbon emissions.

CRDI Engines

Added on: March 11th, 2012 by No Comments

Compared with petrol, diesel is the lower quality product of petroleum family. Diesel particles are larger and heavier than petrol, thus more difficult to pulverize. Imperfect pulverization leads to more unburnt particles, hence more pollutant, lower fuel efficiency and less power.

Common-rail technology is intended to improve the pulverization process. Conventional direct injection diesel engines must repeatedly generate fuel pressure for each injection. But in the CRDI engines the pressure is built up independently of the injection sequence and remains permanently available in the fuel line. CRDI system that uses an ion sensor to provide real-time combustion data for each cylinder. The common rail upstream of the cylinders acts as an accumulator, distributing the fuel to the injectors at a constant pressure of up to 1600 bar. Here high-speed solenoid valves, regulated by the electronic engine management, separately control the injection timing and the amount of fuel injected for each cylinder as a function of the cylinder’s actual need.

In other words, pressure generation and fuel injection are independent of each other. This is an important advantage of common-rail injection over conventional fuel injection systems as CRDI increases the controllability of the individual injection processes and further refines fuel atomization, saving fuel and reducing emissions. Fuel economy of 25 to 35 % is obtained over a standard diesel engine and a substantial noise reduction is achieved due to a more synchronized timing operation. The principle of CRDi is also used in petrol engines as dealt with the GDI (Gasoline Direct Injection) , which removes to a great extent the draw backs of the conventional carburetors and the MPFI systems.
CRDi stands for Common Rail Direct Injection.

Biofuels as Blending Components

Added on: March 10th, 2012 by No Comments

The single largest source of energy in India after coal is petroleum, about two third of which is imported. The petroleum derived fuels i.e. Motor gasoline and diesel are the two major fuels extensively used today.

The high dependence on imported source of energy is an issue related to energy security of the country. And combustion of fossil fuels has been recognized as a major cause of air pollution in Indian cities. Although CNG and LPG are being promoted as clauses alternatives but both of them are short in supply and we have to depend on imports to meet the requirements. In the new Petroleum policy passed on 6th October this year though CNG and LPG are promoted but petrol and diesel continue to remain are the 2 major fuels to be used.

We therefore need to look for cleaner alternatives which could not only decrease pollution but also our dependence on other countries. Among the various alternatives biofuels like ethanol and bio-diesel which can be produced from a host of biosource can be easily be used as blending components of both petrol and diesel in existing engines without modifications. Unlike CNG and LPG new infrastructure for supply and distribution of fuel. Further these fuels production will help use surplus agriculture produce and help in rural development. Ethanol is used more in petrol engines, bio diesel finds application in diesel engines. They add oxygen to respective fuels, which in turn improves combustion efficiency and reduces harmful exhaust emissions.

Biofuels

Added on: March 10th, 2012 by No Comments

The energy crisis is not just a local or national issue but a global one as well. Various groups are responding to energy needs in particular ways—the U.S. and several other countries are looking into synthetic biology to address these problems. Research in this new field, as it is emerging in the United States, is largely devoted to the production of biofuels. Several institutions, which we will call “biofuels interest groups,” envision this energy source to play a significant role in the remediation of current energy challenges. But what are the current challenges that are motivating these groups to pursue this particular resource through a particular and new science such as synthetic biology? After an examination of four of these interest groups, stationed here in the U.S., we have come to the conclusion that the energy crisis to which each group responds is framed by them in a particular way such that biofuels plays a major, if not the only viable and sustainable, role in the remediation of the problem. These groups claim that synthetic biology offers unique and viable paths toward a sustainable future. We will examine exactly what kinds of future are illustrated by each institution—what they mean by a “sustainable future”—by identifying the views, resources, technologies, and management strategies of each group. In addition we will situate them in their human practices context to view not only what they plan to do, but how and to what extent they will carry out their plan. The groups we present are the Joint Bioengineering Institute (JBEI), Amyris Biotechnologies, and the Energy Biosciences Institute (EBI). In order to assess the feasibility of these models outside of the lab we will present a section which provides an overview of the current socio-political atmosphere in which they must operate. This section examines alternative approaches to the energy crisis, motivations for realizing a certain approach, and the decision making forces at play. Two distinct ideologies are represented by the US Department of Energy (DOE) and Tad Patzek to aid in this discussion.

Hyperplane

Added on: March 10th, 2012 by No Comments

A new concept for flight to orbit is described in this paper. It involves mass addition to an ascending, air-breathing, hypersonic lifting vehicle. General laws for flight to orbit with mass addition are developed, and it is shown that payload capabilities are higher than even the most advanced rocket launchers. Hyperplanes are multipurpose, fully reusable aerospace vehicles. These vehicles are using air-breathing engines and can take-off from any conventional airport. They are multipurpose vehicles in the sense that they be used for passenger or freight transport as well as satellite launching. Detailed studies emerged a new concept for hydrogen-fuelled, horizontal take off, fully reusable, single stage hypersonic vehicle, called HYPERPLANE. Avatar, a mini-aerospace plane, design is a technology demonstrator for hypersonic transportation. It is a scaled down version of hyperplane.

Hyperplanes are multipurpose, fully reusable aerospace vehicles. These vehicles are using air-breathing engines and can take-off from any conventional airport. They are multipurpose vehicles in the sense that they be used for passenger or freight transport as well as satellite launching. The key enabling technology for hyper planes is scramjet engines which uses air breathing engine technology. The hyperplanes requires a booster rocket which will give it the supersonic velocity required for scramjet operation. Thus the hyperplanes require normal jet engines for horizontal take off, then a rocket to boost the velocity and a scramjet to sustain the hypersonic speed. Once operational it can even launch satellites at lesser costs compared to rockets. Many nations are working on hyperplane technology, which include USA, Russia, India etc.The only successful hypersonic flight was shown by X-43 of USA.The hyperplane Avatar which is developed by India is expected to be used as a reusable missile launcher. This would be the most modern technology which will revolutionize the modern day’s travel.Here we will discus about the working ,advantages ,disadvantages and various examples of hyperplanes.

Abrasive Blast Cleaning

Added on: March 9th, 2012 by No Comments

An abrasive is a material, often a mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away. While finishing a material often means polishing it to gain a smooth, reflective surface it can also involve roughening as in satin, matte or beaded finishes.

Abrasives are extremely commonplace and are used very extensively in a wide variety of industrial, domestic, and technological applications. This gives rise to a large variation in the physical and chemical composition of abrasives as well as the shape of the abrasive. Common uses for abrasives include grinding, polishing, buffing, honing, cutting, drilling, sharpening, and sanding (see abrasive machining). (For simplicity, “mineral” in this article will be used loosely to refer to both minerals and mineral-like substances whether man-made or not.)

Files act by abrasion but are not classed as abrasives as they are a shaped bar of metal. However, diamond files are a form of coated abrasive (as they are metal rods coated with diamond powder).

Abrasives give rise to a form of wound called an abrasion or even an excoriation. Abrasions may arise following strong contract with surfaces made things such as concrete, stone, wood, carpet, and roads, though these surfaces are not intended for use as abrasives.

Hydro Drive

Added on: March 8th, 2012 by No Comments

Hydro forming is the process by which water pressure is used to form complex shapes from sheet or tube material.

Applications of hydro forming in automotive industry are gaining globally in popularity. The trend in auto manufacturing of making parts lighter and more complicated with necessary strength reinforcement only where required is on the rise. The capability of hydro forming is more fully used to produce such complicated parts.

Tyres

Added on: March 8th, 2012 by No Comments

The primary purpose of the tyre is to provide traction.

  1. Tyres also help the suspension absorb road shocks, but this is a side benefit.
  2. They must perform under variety of conditions. The road might be wet or dry; paved with asphalt, concrete or gravel; or there might be no road at all.
  3. The car might be traveling slowly on a straight road, or moving quickly through curves or over hills. All of these conditions call for special requirements that must be present, at least to some degree, in all tyres.
  4. In addition to providing good traction, tyres are also designed to carry weight of the vehicle, to withstand side thrust over varying speeds and conditions, and to transfer braking and driving torque to the road.
  5. As the tyre rolls on the road, friction is created between the tyre and the road. This friction gives the tyre its traction.
  6. Although good traction is desirable, it must be limited.
  7. Too much traction means there is too much friction.
  8. Too much friction means there is lot of rolling resistance.
  9. Rolling resistance wastes engine power and fuel, therefore it must be kept to a minimal level. This dilemma is a major concern in designing today’s tyres.
  10. The primary purpose of the tyre is to provide traction along with carrying the weight of the vehicle.

Four Wheel Steering System

Added on: March 7th, 2012 by 1 Comment

Four-wheel steering, 4WS, also called rear-wheel steering or all-wheel steering, provides a means to actively steer the rear wheels during turning maneuvers. It should not be confused with four-wheel drive in which all four wheels of a vehicle are powered. It improves handling and help the vehicle make tighter turns.

Production-built cars tend to understeer or, in few instances, oversteer. If a car could automatically compensate for an understeer/oversteer problem, the driver would enjoy nearly neutral steering under varying conditions. 4WS is a serious effort on the part of automotive design engineers to provide near-neutral steering.

The front wheels do most of the steering. Rear wheel turning is generally limited to 50-60 during an opposite direction turn. During a same direction turn, rear wheel steering is limited to about 10-1.50.

When both the front and rear wheels steer toward the same direction, they are said to be in-phase and this produces a kind of sideways movement of the car at low speeds. When the front and rear wheels are steered in opposite direction, this is called anti-phase, counter-phase or opposite-phase and it produces a sharper, tighter turn.

Common Rail Direct Injection

Added on: March 7th, 2012 by No Comments

Compared with petrol, diesel is the lower quality product of petroleum family. Diesel particles are larger and heavier than petrol, thus more difficult to pulverize. Imperfect pulverization leads to more unburnt particles, hence more pollutant, lower fuel efficiency
and less power.

Common-rail technology is intended to improve the pulverization process. Conventional direct injection diesel engines must repeatedly generate fuel pressure for each injection. But in the CRDI engines the pressure is built up independently of the injection sequence and remains permanently available in the fuel line. CRDI system that uses an ion sensor to provide real-time combustion data for each cylinder. The common rail upstream of the cylinders acts as an accumulator, distributing the fuel to the injectors at a constant pressure of up to 1600 bar. Here high-speed solenoid valves, regulated by the electronic engine management, separately control the injection timing and the amount of fuel injected for each cylinder as a function of the cylinder’s actual need.

In other words, pressure generation and fuel injection are independent of each other. This is an important advantage of common-rail injection over conventional fuel injection systems as CRDI increases the controllability of the individual injection processes and further refines fuel atomization, saving fuel and reducing emissions. Fuel economy of 25 to 35 % is obtained over a standard diesel engine and a substantial noise reduction is achieved due to a more synchronized timing operation. The principle of CRDi is also used in petrol engines as dealt with the GDI (Gasoline Direct Injection) , which removes to a great extent the draw backs of the conventional carburetors and the MPFI systems.

Cryogenics and its Space Applications

Added on: March 7th, 2012 by Afsal Meerankutty 3 Comments

Cryogenics is the study of how to get to low temperatures and of how materials behave when they get there. Besides the familiar temperature scales of Fahrenheit and Celsius (Centigrade), cryogenicists use other temperature scales, the Kelvin and Rankine temperature scale. Although the apparatus used for spacecraft is specialized, some of the general approaches are the same as used in everyday life. Cryogenics involves the study of low temperatures from about 100 Kelvin to absolute zero.

One interesting feature of materials at low temperatures is that the air condenses into a liquid. The two main gases in air are oxygen and nitrogen. Liquid oxygen, “lox” for short, is used in rocket propulsion. Liquid nitrogen is used as a coolant. Helium, which is much rarer than oxygen or nitrogen, is also used as a coolant. In more detail, cryogenics is the study of how to produce low temperatures or also the study of what happens to materials when you have cooled them down.

Magnetic Refrigeration

Added on: March 7th, 2012 by Afsal Meerankutty 2 Comments

Magnetic refrigeration is a technology that has proven to be environmentally safe. models have shown 25% efficiency improvement over vapor compression systems. In order to make the Magnetic Refrigerator commercially viable, scientists need to know how to achieve larger temperature swings. Two advantages to using Magnetic Refrigeration over vapor compressed systems are no hazardous chemicals used and they can be up to 60% efficient.
There are still some thermal and magnetic hysteresis problems to be solved for these first-order phase transition materials that exhibit the GMCE to become really useful; this is a subject of current research. This effect is currently being explored to produce better refrigeration techniques, especially for use in spacecraft. This technique is already used to achieve cryogenic temperatures in the laboratory setting (below 10K).

The objective of this effort is to determine the feasibility of designing, fabricating and testing a sensor cooler, which uses solid materials as the refrigerant. These materials demonstrate the unique property known as the magneto caloric effect, which means that they increase and decrease in temperature when magnetized/demagnetized. This effect has been observed for many years and was used for cooling near absolute zero. Recently, materials are being developed which have sufficient temperature and entropy change to make them useful for a wide range of temperature applications. The proposed effort includes magneto caloric effect material selection, analyses, design and integration of components into a preliminary design. Benefits of this design are lower cost, longer life, lower weight and higher efficiency because it only requires one moving part – the rotating disk on which the magneto caloric material is mounted. The unit uses no gas compressor, no pumps, no working fluid, no valves, and no ozone-destroying chlorofluorocarbons/hydro chlorofluorocarbons (CFC’s/HCFC’s). Potential commercial applications include cooling of electronics, super conducting components used in telecommunications equipment (cell phone base stations), home and commercial refrigerators, heat pumps, air conditioning for homes, offices and automobiles, and virtually any place that refrigeration is needed.

Electronically Controlled Suspension System

Added on: March 6th, 2012 by No Comments

An electronically controlled vehicle suspension system that can be switched between a hard and a soft state has a mode selection switch that permits an alternative choice between a hard mode that puts the suspension in the hard state and an automatic mode that automatically puts the suspension into the soft or hard state depending upon the vehicle conditions. A control device is also provided that puts the suspension in the automatic mode, in preference to the mode to which the mode selection switches has been set, when the engine key switch is turned on for the start. This electronically controlled suspension system is therefore always in the automatic mode when the engine has been started so that the suspension is automatically switched between the soft and hard states depending on the vehicle conditions, thereby assuring a comfortable ride at all times.

Precision Engineering and Practice

Added on: March 4th, 2012 by No Comments

There are three terms often used in precision practices and they are often used incorrectly or in a vague manner. The terms are accuracy, repeatability, and resolution. Because the present discussion is on machining and fabrication methods, the definitions will be in terms related to machine tools. However, these terms have applicability to metrology, instrumentation, and experimental procedures, as well.

Precision engineering deals with many sources of error and its solution. Precision is the most important think in the manufacturing field. Machining is the important part of manufacturing process. Many factor like feedback variables, machine tool variables, spindle variabls,wokpice vaiabls,envronmantal effect thermal errors etc.. affect the accuracy of machine. Main goal of precision engineering is to reduce the uncertainty of dimensions. Achieve the exact dimension is vary difficult . So tolerance is allowed on work piece.

High Efficiency Miller Cycle Gas Engine

Added on: March 4th, 2012 by No Comments

The output of gas engines for cogeneration mainly ranges from 100 to 1 000 kW. The present gas engines are broadly classified in two types: lean-burn system (1) and stoichiometric air-fuel ratio combustion system, with the lower output engines using the stoichiometric Air-fuel ratio combustion system while the medium and large size engines adopting the lean-burn system. The lean-burn system generally features in high generating efficiency and low NOx emission in addition to the excellent endurance of the low-temperature combustion flame.

Mitsubishi Heavy Industries, Ltd. (MHI) and Osaka Gas Co., Ltd. have jointly applied the Miller cycle to a lean-burn gas engine to develop the world’s first gas engine in this class with the generating efficiency standing at 40%. With the 280 kW engine released commercially in April 2000 after having cleared the endurance test over 4 000 hours, this paper describes the main technologies and performance specifications for this engine as well as for the series of engines planned in the future.