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  • saurabhjain

    Calling Mechanical Engineers to collaborate on Twitter

    By saurabhjain

    If you are a mechanical engineering professional and have a twitter account .. we invite you in our mechanical engineering  campaign to collaborate on twitter.. Retweet the following status on https://twitter.com/mechportal/status/646544243649961985 Look forward for your presence. Regards Mechanical Engineeirng forum
    • 5 comments
    • 1,517 views
  • DrD

    A Question for Readers

    By DrD

    Many of you have asked me various questions, so now it is my turn. Let me lay a bit of background first, and then the questions.   I have had some conversations recently with JAG (one of the other writers here at ME Forums) regarding the choice of software for 3D modeling and analysis. JAG has made some excellent suggestions, specifically a cloud based program called Onshape. Unfortunately, for reasons that are unclear, my computer cannot run Onshape; I have worked with their help people for several hours, all to no avail. JAG recommends this in part because there is a "free version for the hobbyist" and a relatively inexpensive "full version for the professional." That is pretty attractive, but since I can't run it, I'm stuck.   I gather that virtually all engineering colleges these days are teaching some sort of 3D modeling and analysis software, but that raises a few questions in my mind. 1. If your college teaches brandX 3D software, what will you do when you go to work for a small company that cannot afford anything more than 2D drafting (simple CAD), with no analysis capability at all? How will you do your job then? You probably have your own pocket calculator, but will you have your own copy of ANSYS or Pro-E? 2. What software does your school teach (every students should have an answer to this question, so I expect lots of replies on this one!)? 3. If you have used software extensively for analysis of engineering problems (beam deflections, stress analysis, fluid flow, heat transfer, etc), are you confident  that you will be able to work all of those problems if there is no such software available to you on the job?   I might add, as sort of a postscript, most of you know that I am older than dirt (I just had another birthday, so the situation is even worse!), so I tend to look at things from an elderly perspective. One of my great fears as a working engineer was "What will happen when I'm ask to do something that I don't know how to do?" It happened more than once, and it usually resulted in a flurry of intense research to come up to speed on whatever topic was involved. I could usually do that because I have a pretty good library, and I knew how to use a university library as well. But in terms of software, I was always concerned that I had no FEA program, so how could I do problems that others were doing by FEA? I have come up with some interesting work-arounds, including writing my own FEA for some problems, but I never wanted to be dependent on software that I could not afford to own. So, back to my questions about: How are you going to buy your own copy of ANSYS? DrD
    • 28 comments
    • 2,904 views
  • DrD

    #20 -- A Question of Stability (Revised)

    By DrD

    Mechanics Corner
        A Journal of Applied Mechanics and Mathematics by DrD, #20
        © Machinery Dynamics Research, 2015
    A Question of Stability Introduction     The word stability in its several forms is widely used in nontechnical communication. A person whose life it highly consistent from day to day is said to have a stable life. When the political situation in a particular area appears to be unlikely to change, it is said to be stable. A person who is well balanced and unlikely to be easily provoked to anger is said to be a stable person. When the medical condition of a sick or injured person ceases to get worse, the person is said to be stabilized. A company on the verge of bankruptcy is said to be an unstable company. But what does the word stability mean in a technical context? Each of the foregoing examples hints at the technical meaning without really being explicit about it.   A factor g = accel of gravity was missing in the potential energy expression. That is now corrected.
        
     
        Stability.pdf
    • 16 comments
    • 5,724 views
 

Sheet pipe piles

1) How to make the spiral pipe 2) Accessory of the pipe (Use to connect the pipe and bring pipe up) 3) Application 4) Drawing  Click Download drawing of Bridge foundation 3D ( reference drawing ) Click Download catalogue of the product  

truongtienminhck

truongtienminhck

 

The Design Sense

Mechanical Design and More   Why Design? The new era is flooded with products - Virtual or Physical. And with no surprise, everything needs to be designed. We are doing it from long back, since we are bringing something new or may be inventing. Design is the medium which brings your thoughts into a physical (nowadays virtual) form.   Virtual/Web design Remember the old days websites or software packages - They were largely comprised of text, and design layout did not exist much. While later versions had some design, they were still extremely basic, consisting mainly of tags for headers, paragraphs, and links. Visual considerations such as typography, imagery, and navigation were still things of the not-too distant future.   pc: www.vdoit.in   And now, we are into a new age where we look forward to User Interface and User Experience (UI/UX) designers to improve overall experience and usability of webisites and software packages.   There is a whole world behind these two words!!   Just take an example of one of the largest social networking website, Facebook - Who decides, where will be your cover pic and where should be the display pic be located in your wall. Not only this, there are whole lot of stuffs on each and every website. Simple placement and positions of the buttons will change the overall experience of the user. This is where UI/UX designer are working hard by understanding human nature and behavior of doing things when they are 'online'.   pc: www.mockingbot.com     Just to add, each and every thing which you look into a website, software package or mobile applications , be it a logo, buttons, stickers and the entire range of interface details which you see are being designed by someone - Designers. Imagine the vast amount of work involved in this!  
Physical/Mechanical design Being a Mechanical Design Engineer, this excites me more.   When I say "Mechanical", does it restricts me to gears, bolts-nuts, cam-shaft, car/aerospace bodies and parts?   Well not at all !   Name a product around you which you think is not of 'mechanical' genre - Mobile phones, Television (its remote too), Refrigerators, Air conditioners and many more. Most of us would say these are electronics/electrical products. They are listed under 'Electronics' category in amazon and flipkart too.

     
Now, understand this - All of these products are obviously being invented/reinvented by electrical or electronics engineers and their functionality depends on basic rules and principles of these engineering discipline, but their actual physical being is a work of physics and mathematics. When I say physics and mathematics, its basically mechanical design in broader sense. For instance, the electronic board inside a mobile phone or TV is work of electronics ( circuit design, voltage calculations, etc), but they never tell how the mobile phone should look or feel to the end user when they will hold it. Also, electrical engineer can not tell how a TV to be wall mounted, what should be the screen thickness, corners, etc. In more engineering sense, the entire design is actually work of a Mechanical Design engineer who designs the fits/forms and the look of the appliance. Obviously when I say 'look', it opens a whole new world which revolves around aesthetics.  Probably, I will talk about ergonomics and aesthetics some other time.   The Design Sense Any design needs to fulfill certain requirements which comes from end users. But the real question is what inspires a designer to design something new or may be modify an existing product to something new and more usable. The designer must satisfy all what is required by the user and obviously the standards set upon it (and off course the laws of physics and mathematics). These all might drive the design and product structure but these can never drive how the product will look or feel to the user. At some instances the user might not be interested on how it looks, it should perform and that's all counts. pc: www.api-university.com
The design sense of the designer plays an important role on how the product is being designed and what features are built to satisfy all the requirements. Be it a UI/UX designer or Mechanical designer, designing under requirements are achievable like solving a problem but developing a design sense is something which comes with time and experience. In a way its a work of art. ps: www.designschool.canva.com How do we develop a design sense? When I say DESIGN is work of art, any art comes with time and needs passion. We may learn design tools but the design sense needs dedication. A musician can learn how to play a guitar but can only develop new tunes if he is passionate about it.   Have you ever thought why a particular product is being made/designed the way it is? Let me take a few examples:   1. Bulbs - The iconic shape that blazes in our minds as the quintessential light bulb served two purposes in the advent of lighting: it was easily manufactured using glass-blowing techniques, and its spherical shape was best for controlling heat and light emissions.     2. Golf balls - Are a golf ball's dimples just there for aesthetics? Try aerodynamics - They actually create turbulence in the layer of air surrounding a ball in flight, reducing the drag behind the ball.     Now we know why helmets for cyclists are designed with dimples. But why not aircraft or cars?

  3. Manhole covers - Why they are always round?
They are round almost all over the world, so that they cannot possibly fall through their own holes. Any shape other than a circle would be able to fit through in at least one way.
    Off course few designers took it as challenge, but I am sure they had to make some arrangement, may be a hatch.     So now you know why certain features are designed in these products and why it was a sensible approach.

I will discuss a lot more about design - Design thinking, mechanical design approach and the process to build something new and off course the tools which are used. Log in to  Why Design? The new era is flooded with products - Virtual or Physical. And with no surprise, everything needs to be designed. We are doing it from long back, since we are bringing something new or may be inventing. Design is the medium which brings your thoughts into a physical (nowadays virtual) form. Virtual/Web design Remember the old days websites or software packages - They were largely comprised of text, and design layout did not exist much. While later versions had some design, they were still extremely basic, consisting mainly of tags for headers, paragraphs, and links. Visual considerations such as typography, imagery, and navigation were still things of the not-too distant future.   pc: www.vdoit.in   And now, we are into a new age where we look forward to User Interface and User Experience (UI/UX) designers to improve overall experience and usability of webisites and software packages.   There is a whole world behind these two words!!   Just take an example of one of the largest social networking website, Facebook - Who decides, where will be your cover pic and where should be the display pic be located in your wall. Not only this, there are whole lot of stuffs on each and every website. Simple placement and positions of the buttons will change the overall experience of the user. This is where UI/UX designer are working hard by understanding human nature and behavior of doing things when they are 'online'.   pc: www.mockingbot.com     Just to add, each and every thing which you look into a website, software package or mobile applications , be it a logo, buttons, stickers and the entire range of interface details which you see are being designed by someone - Designers. Imagine the vast amount of work involved in this!  
Physical/Mechanical design Being a Mechanical Design Engineer, this excites me more.   When I say "Mechanical", does it restricts me to gears, bolts-nuts, cam-shaft, car/aerospace bodies and parts?   Well not at all !   Name a product around you which you think is not of 'mechanical' genre - Mobile phones, Television (its remote too), Refrigerators, Air conditioners and many more. Most of us would say these are electronics/electrical products. They are listed under 'Electronics' category in amazon and flipkart too.

     
Now, understand this - All of these products are obviously being invented/reinvented by electrical or electronics engineers and their functionality depends on basic rules and principles of these engineering discipline, but their actual physical being is a work of physics and mathematics. When I say physics and mathematics, its basically mechanical design in broader sense. For instance, the electronic board inside a mobile phone or TV is work of electronics ( circuit design, voltage calculations, etc), but they never tell how the mobile phone should look or feel to the end user when they will hold it. Also, electrical engineer can not tell how a TV to be wall mounted, what should be the screen thickness, corners, etc. In more engineering sense, the entire design is actually work of a Mechanical Design engineer who designs the fits/forms and the look of the appliance. Obviously when I say 'look', it opens a whole new world which revolves around aesthetics.  Probably, I will talk about ergonomics and aesthetics some other time. The Design Sense Any design needs to fulfill certain requirements which comes from end users. But the real question is what inspires a designer to design something new or may be modify an existing product to something new and more usable. The designer must satisfy all what is required by the user and obviously the standards set upon it (and off course the laws of physics and mathematics). These all might drive the design and product structure but these can never drive how the product will look or feel to the user. At some instances the user might not be interested on how it looks, it should perform and that's all counts. pc: www.api-university.com
The design sense of the designer plays an important role on how the product is being designed and what features are built to satisfy all the requirements. Be it a UI/UX designer or Mechanical designer, designing under requirements are achievable like solving a problem but developing a design sense is something which comes with time and experience. In a way its a work of art. ps: www.designschool.canva.com How do we develop a design sense? When I say DESIGN is work of art, any art comes with time and needs passion. We may learn design tools but the design sense needs dedication. A musician can learn how to play a guitar but can only develop new tunes if he is passionate about it.   Have you ever thought why a particular product is being made/designed the way it is? Let me take a few examples:   1. Bulbs - The iconic shape that blazes in our minds as the quintessential light bulb served two purposes in the advent of lighting: it was easily manufactured using glass-blowing techniques, and its spherical shape was best for controlling heat and light emissions.     2. Golf balls - Are a golf ball's dimples just there for aesthetics? Try aerodynamics - They actually create turbulence in the layer of air surrounding a ball in flight, reducing the drag behind the ball.     Now we know why helmets for cyclists are designed with dimples. But why not aircraft or cars?

  3. Manhole covers - Why they are always round?
They are round almost all over the world, so that they cannot possibly fall through their own holes. Any shape other than a circle would be able to fit through in at least one way.
    Off course few designers took it as challenge, but I am sure they had to make some arrangement, may be a hatch.     So now you know why certain features are designed in these products and why it was a sensible approach.

I will discuss a lot more about design - Design thinking, mechanical design approach and the process to build something new and off course the tools which are used.   Mechanical Design and More    

yashlay sinha

yashlay sinha

 

Effect of the type of mesh on a Pipe flow problem

The project explains how the type of mesh can influence the results obtained for the mixing of flow in a pipe. The simulation is done on a cloud-based CAE platform called SimScale. The link to the project is here. This project is a part of the SimScale Professional Training on CFD (Computational Fluid Dynamics).   The pipe flow geometry, originally uploaded by the SimScale Staff, available in the public projects.   For this internal flow problem, a Hex-dominant parametric mesh is used. Two types of meshes are created for the problem - a coarse mesh ( which accommodates all the features of the geometry) and a fine mesh ( by increasing the fineness).   Coarse mesh ( Fineness: 1-Very coarse)   Fine mesh ( Fineness : 4-Fine)   The same type of analysis is performed for both the meshes (Fluid dynamics: Incompressible). Same boundary conditions and simulation controls are defined for both the meshes.   Simulation run: Coarse mesh   Simulation run: Fine mesh   The simulation results are post-processed (clip filter is used) to get the contour plot of the velocity flow field.   Post-processor screenshot for coarse mesh   Post-processor screenshot for fine mesh   As revealed by the results the fines mesh captures specific physics (like flow separation and vorticities) more accurately. Isn't that expected? Well, not always!       This blog was previously posted on Behance.              

Tania Alam

Tania Alam

 

Boilers: Introduction and Classification

The boiler system comprises a feed-water system, steam system, and fuel system. The feed-water system supplies treated water to the boiler and regulate it automatically to meet the steam demand. Various valves and controls are provided to access for maintenance and monitoring. The steam system heats and vaporizes the feed water and controls steam produced in the boiler. Steam is directed through a piping system to the application. Throughout the system, steam pressure is regulated using valves and monitored with steam pressure gauges. The fuel system consists of all equipment used to supply of fuel to generate the necessary heat. The equipment required in the fuel system depends on the type of fuel used in the system. Boilers Classification: There are a large number of boiler designs, but boilers can be classified according to the following criteria: 1. According to Relative Passage of water and hot gases: Water Tube Boiler: A boiler in which the water flows through some small tubes which are surrounded by hot combustion gases, e.g., Babcock and Wilcox, Stirling, Benson boilers, etc. Fire-tube Boiler: The hot combustion gases pass through the boiler tubes, which are surrounded by water, e.g., Lancashire, Cochran, locomotive boilers, etc. 2. According to Water Circulation Arrangement: Natural Circulation: Water circulates in the boiler due to density difference of hot and water, e.g., Babcock and Wilcox boilers, Lancashire boilers, Cochran, locomotive boilers, etc. Forced Circulation: A water pump forces the water along its path, therefore, the steam generation rate increases, Eg: Benson, La Mont, Velox boilers, etc. 3. According to the Use: Stationary Boiler: These boilers are used for power plants or processes steam in plants. Portable Boiler: These are small units of mobile and are used for temporary uses at the sites. Locomotive: These are specially designed boilers. They produce steam to drive railway engines. Marine Boiler: These are used on ships. 4. According to Position of the Boilers: Horizontal, inclined or vertical boilers 5. According to the Position of Furnace Internally fired: The furnace is located inside the shell, e.g., Cochran, Lancashire boilers, etc. Externally fired: The furnace is located outside the boiler shell, e.g., Babcock and Wilcox, Stirling boilers, etc. 6. According to Pressure of steam generated Low-pressure boiler: a boiler which produces steam at a pressure of 15-20 bar is called a low-pressure boiler. This steam is used for process heating. Medium-pressure boiler: It has a working pressure of steam from 20 bars to 80 bars and is used for power generation or combined use of power generation and process heating. High-pressure boiler: It produces steam at a pressure of more than 80 bars. Sub-critical boiler: If a boiler produces steam at a pressure which is less than the critical pressure, it is called as a subcritical boiler. Supercritical boiler: These boilers provide steam at a pressure greater than the critical pressure. These boilers do not have an evaporator and the water directly flashes into steam, and thus they are called once through boilers. 7. According to charge in the furnace. Pulverized fuel, Supercharged fuel and Fluidized bed combustion boilers.

Rishabh Pandey

Rishabh Pandey

 

Strength calculation

hello All,  i am working as a design engineer and i am working on sheet metal structures. i am looking at the calculations to decide on the thickness of sheet metal to carry a particular load. i calculated the sectional modulus of the design based on the cross sectional area of sheet metal and it is well within the sectional modulus of material. I would like to know werher the approach is right or are there other calculations which i should do before deciding the thickness?. request to suggest on the above please find the image below for reference

abhilashNJ

abhilashNJ

 

Pre- Crash Sensors for Pre-Crash Safety

Many research and development have been conducted  to meet society needs for safer vehicles. Particularly, occupant protection system such as air bags, developed and introduced in order to reduce occupant injuries in crashes, are currently installed in most vehicles making significant contribution to safety.   Meanwhile, many studies have been made into the development of active safety technologies that help to avoid crash accidents. Unfortunately the current situation is that the active safety technologies are not sufficient spread. Adaptive cruise control has been commercialized since 1995, but its primary use has not been convincing.Some audible warning system  are also being offered, but have not yet reached widespread use.   Toyota Motors corporation has explored the possibility of producing an active safety system employing Intelligent Transport System (ITS) technologies,through participation in the Advanced Safety Vehicle (ASV) projects started in 1991 and led by ministry of land , infrastructure and transport.   Critical basis ITS technologies for application to ASV includes a surround monitoring sensor and an obstacle determination algorithm which combines information from the surround monitoring sensor with other information to identify obstacles with which the vehicle is likely to actually crash.   The sensors and crash determination algorithm for an active safety system should be capable of reliably determining that  a crash will not occur in non-crash situation. Advanced technologies are required to make these predictions and judgments correctly while also taking into account the driver's operation and behavior and this has hampered widespread of active safety systems.   Pre-crash safety system has been developed which operates only when it is judged that a crash cannot be avoided by most drivers under normal driving conditions. Determining unavoidable crashes is restricted to a short time period immediately before the crash so as to improve the reliability of the judgement. In addition the pre-crash system is made with a mechanism and system that will not place the driver and the running vehicle in an unsafe condition even if the system is operated unnecessarily. As a result the world's first commercial system has been achieved.              

saurabh kumar tiwari

saurabh kumar tiwari

V2V (Vehicle to Vehicle) Communication

The objective of ambient intelligence is to create an intelligent daily space, which is immediately usable and integrated into our homes, our offices, our roads, our cars, and everywhere. This new concept must be invisible; it must blend in with our normal environment and must be present when we need it.   One of the application of this concept consists of providing our cars and roads with capabilities to make road more secure (information about the traffic, accidents, dangers, possible detours, weather, etc.) and to make our time on road more enjoyable (Internet access, network games, helping two peoples follow each other on the road, chat, etc). These applications are typical example of what we call an Intelligent Transport System (ITS) which goal is to improve security, efficiency and enjoyment in road transport through the use of new technologies for information and communication.   Traditional traffic management systems are based on centralized infrastructures where cameras and sensors implemented along the road collect information on density and traffic state and transmit this data to a central unit to process it and make appropriate decisions. This type of system is very costly in terms of deployment is characterized by a long reaction time for processing and information transfer in a context where information transmission delays is vital and is extremely important in this type of system. In addition, these devices on roads requires periodic and expensive maintenance. Consequently, for large scale deployment of this type of system, important investment is required in communication and system infrastructure. However, with the rapid development of wireless communication technologies, location and sensors, a new decentralized architecture based on vehicle to vehicle communications has created a very real interest in these last few years for car manufacturers, R&D community and telecom operators. This type of architecture relies on a distributed and autonomous system and is made up of the vehicles themselves without the support of fixed infrastructure for data routing.     The main objectives of an intelligent transportation system includes:   the improvement of trip security the improvement of global efficiency of the transportation system by reducing travel time and congestion the integration of transportation in a durable development policy particularly by reducing gas emissions for light vehicles and heavy trucks and  by optimizing maintenance of the infrastructure the improvement of user comfort by providing him with a selection of information, decision support, guidance and internet access services.                  

saurabh kumar tiwari

saurabh kumar tiwari

 

Automated Manual Transmission

MT (manual transmission) uses simple spur gears providing excellent transmission efficiency and thus typically get 10% or better fuel mileage than current ATs (automated transmissions). The object of the ATM (automated manual transmission ) is to automate starting and gear shifting while retaining this excellent fuel efficiency. A round of fierce competition was triggered among European manufacturers to see who would be the first to develop what is generally known as a conventional AMT that attempts to automate the shifting of MT. The problem with this design is that the drive torque is momentarily interrupted during shifting. This results in a very different shift feeling from an AT, and thus never saw the wide spread acceptance as a replacement for the conventional AT in mainstream vehicles. This was more recently followed by a twin clutch AMT that is receiving great deal of attention. Supporting smooth and responsive shifting much like an AT, the twin-clutch AMT has been installed by European vehicle manufacturer on some high engine capacity sport cars beginning last fall. Hitachi group has now developed an original torque-assist AMT that is fundamentally different from these other two approaches.   TORQUE-ASSIST AMT
In order to achieve widespread acceptance as a replacement for conventional transmissions, the next generation must provide the good fuel economy of an MT, the effortless shifting of an AT, and must also be compact and affordable. Unfortunately, the conventional AMT fails to achieve the seamless shifting of an AT and the twin clutch AMT is difficult to implement compactly and cost effectively.   Hitachi Group has proposed a third way that does meet all the above requirements a torque assist AMT and is now in the process of developing this system. A key advantage of this approach is that it can be implemented with relatively little modification to existing AMTs by simple adding a friction clutch called as assist clutch to the transmission. Action of the assist clutch effectively solves the torque interruption  problem of the conventional AMT while providing the smooth gear shifting of an AT.  A compact and economical torque assist AMT could thus be implemented fairly easily for application on mainstream FF (front-engine front-drive) compact vehicles with engine displacement with 2 liters.                    

saurabh kumar tiwari

saurabh kumar tiwari

 

DRIVERLESS CARS

For generations, the automobile industry has been a source of innovation and economic growth. The ability to drive is a symbol of mobility and independence that spans generations. Clearly, automobiles play a significant role in our lives and afford many benefits to society.   Yet for all benefits conferred on society, no other invention in the history of civilian technology has caused as much harm as the automobile. Every 30 seconds. someone dies in a traffic accident, adding up to well over 1 million deaths each year. In the US automobile accidents are the leading cause of death for people between the age of 3 and 34. Moreover,human error is the cause of over 90% of automobile accidents.   In addition the inefficiencies related with the automobile usage is staggering. Most automobiles sit unused more than 95% of their life span, and a freeway operating at maximum  efficiency has automobiles on only 5% of its surface. In congested urban areas, 40% of all gasoline used is spent when car looks for parking spaces. Furthermore, in some US cities, parking lots comprise more than third of the land, becoming the single salient landscape feature of our built environment.   Since its inception of the commercial auto industry in the late 1890s, cars have become increasingly safe and convenient. Recently, car makers have begun to introduce advanced driver-assistance systems such as adaptive cruise control (which automates accelerating and braking) and active lane assist (which automates steering). These systems have become capable enough that new luxury vehicles can drive themselves in slow moving highway traffics. Research into autonomous cars has progressed remarkably since the first demonstrations in the 1980s. In 2010, four driver less vans traveled from Italy to China. In august of 2012, google announced that its self-driving cars had completed over 300,000 miles of accident free autonomous driving. Although self-driving cars may still seems like science friction, Google, many industry analysts, auto suppliers, and car makers project that such cars will be available before 2020.                                                                      

saurabh kumar tiwari

saurabh kumar tiwari

 

CNG in India

Compressed natural gas(CNG) is a fuel that needs no introduction.  it is a cheap fuel to make and use, which is why it is so widespread in public transport. Not to mention that the second hand car market is greatly supported by CNG kits. vehicles like the Honda Civic, Accord and Toyota Corolla are favorites to be bought second hand and then have green fuel kits used to make them easy on the pocket. With diesel deregulation soon to kick in, the price of the oil will head north soon, so CNG seems like a good investment for those with regular usage. here's the brief look at advantages and disadvantages of CNG:   Advantages:   it is the green fuel. the emissions and hydrocarbons that are released as the by product of CNG usage are lesser than those created by regular fuel. Carbon monoxide emission are down by 70-85% while hydrocarbon levels are reduced by 40-60%. the price fluctuation of the natural gas is less. Look back over the past few years and you'll notice that petrol and diesel prices have been on roller coaster ride, but CNG has the relative linear movement. this is because of domestic production which has no dependency on international movements. Engine life improves.Contrary to popular beliefs, CNG is a better fuel for improving engine life as the carbon levels are greatly reduced.   Disadvantages: The performance of the car is reduced significantly. On an average CNG users experience a crash about 10% in performance.  The storage space is eaten up badly. CNG tanks a easily the size of large bag, so boot space is reduced or removes entirely as the fuel storage tank takes up all the room. Availability is not a wide spread as regular gas stations. Within the city users probably have a list of stations that falls in the route, but beyond that it is an uncertainty. This is the reason why cars aren't made to run exclusively on CNG. Blocked injectors. Cars with CNG kits should always be started on petrol and run for few kilometers before being switched to the green fuel. This warms up the engine better and gets the motor well lubricated. Petrol is expensive so drivers often chose not to use it.  Fuel range. Although CNG is a cheaper fuel, the actual range on just CNG is lesser than petrol. Not to mention, running on a close to empty tank reduces the pressure and increases the risk of valve bursting. So, even if the car uses CNG, it is always wise to keep a regular flow of petrol both in tank and in the engine usage.              

saurabh kumar tiwari

saurabh kumar tiwari

 

Desicant Cooling System

In the last 10 years, evaporative and desiccant cooling technology for air conditioning has increased as an alternative for air conditioning systems has increased as an alternative to the conventional vapour compression systems. A typical system combines a dehumidification system that uses a rotary desiccant wheel, with direct or indirect evaporative systems, allowing a filtered and cooled air supplying temperature, humidity and speed conditions that propitiate environmental thermal comfort, even in equatorial and tropical climates. These systems causes a lot of electrical power saving, mainly in place where thermal source energy source are easily found, where the price of electrical energy is high,where the latent heat percentage is high or where the needed air dew point is low. So, evaporative cooling systems that use absorption pre-dehumidification presents a great perspective in thermal comfort. It can be used in co-generation systems, where the needed heat to regeneration can be gotten from gas turbines exhaust gases or internal combustion engines or, still, from steam in plants that use steam turbine.                                                                                                                                                                                                                                                    

saurabh kumar tiwari

saurabh kumar tiwari

 

Experimental Analysis of an Air Washer

Hello World,   Today i will like tell you all about my 4th year project which was on the topic of experimental analysis of an air washer. In the recent sanario the peoples are slowly getting conscious about the beast(pollution) intended to destroy our beautiful sphere(earth). This pollution had drastically spread in our world drastically in few years. It is sad to say but we are only responsible for it. The careless burning of fossil fuels, heavy growth in industries and inventions without considering about the earth safety pushed of us into this undesirable situation.   But now the peoples are thinking about what they are doing and what they had done including the government which taken so many steps for the control on pollution. The scientist's also get conscious about their invention which will be in the favor the reducing pollution.     In India the refrigerants like R 22 is going to be banned in upcoming few years which is one of the major reason for the depletion of the ozone layer which causes global warming and some harmful skin disease's. These things created the requirement for the replacement of old cooling systems and introduction of the new inventions which are environment friendly.   My project was on the same concern me and my friends decided to try the project which can be the one of the substitute of the recent refrigeration system. On the suggestion of our professor we modified the air washer to not only work as an evaporative cooler but also can remove the sulphure dioxide from the air which is one of the gas responsible for green house effect.   In my project my team was using spray type air washer with the very simple design since it become easier to modify.                                                                                                                                                           The spray type air washers consists of a chamber or casing containing a spray nozzle system, a sink for removing the spray water as it falls. And an eliminator section for the removal of moisture in the air. A pump recirculates water at the rate higher than the evaporation rate.   Intimate contact between the spray water and the air flow causes heat and mass transfer between the air and the water. The air washer used in the industries has the basic use to clean air and control the properties of the air as per the requirement.   The air washer can perform two kinds of cooling: 1. Direct evaporative cooling 2.Indirect evaporative cooling   The direct evaporative cooling is done by the direct contact between sprayed water and the flowing air in the chamber. Where the indirect evaporative cooling is done by providing heat exchanger at the front of air washer. The syphon present in the heat exchanger is circulated by the cold water and the hot air is passed through the fins of the heat exchanger. Which causes heat exchange between air and water.   The indirect evaporative cooling was done in my project by the use of car radiator.
AIR WASHER SPECIFICATIONS
BLOWER                suction blower with 1HP, 3PHASE, 440 V and internal diameter 4 inch   NOZZLE SECTION                     the nozzle section consist of:-   1. 4 elbow joints (0.5 inch bore) 2. 3 distributors (0.5 inch bore) 3. 10 vertical pipes (0.5 inch bore & 50 cm length) 4. 10 holes on vertical pipe each (1 mm bore) 5. 5 holes on horizontal pipe each (1 mm bore)   All the components in the nozzle section are made up of PVC material.   The body of the air washer was made up of the aluminium composite pannel.  Two layers of simple cellulose pad was use in the eliminator section to absorb the moisture in the air.                                                                                                                                                                                                                                                                                                  The picture above will give you the brief and real understanding of the project.   The analysis was done with the following aims: 1. circulating the water at normal temperature and analyzing the changes in the property of the air 2. circulating hot water through air washer and analyzing the change in the properties of air 3. circulating chilled water through air washer and analyzing the changes in properties of air   I am providing some videos of working of my project i hope you will like it.   please give reviews on my publish and don't forget to follow. your reviews are precious to me and your following will motivate to share new views thank you.                                                                                               

saurabh kumar tiwari

saurabh kumar tiwari

 

Last Post -- Time to Hang It Up

Mechanics Corner
    A Journal of Applied Mechanics and Mathematics by DrD
    © Machinery Dynamics Research, 2017
Last Post
Time to Hang It Up    
This will be the final post of Mechanics Corner here on Mechanical Engineering Forums. It has run almost exactly two years, and there have been ups and downs along the way. In this final post, I want to reflect a bit on my original goals for the blog, and also on what has actually happened. When our host first proposed to me that I might write a blog for ME Forums, I was excited about it. About half of my career had been spent in engineering education, and I always loved working with students. It seemed like a way to get back to something that I had long enjoyed, and so I accepted his suggestion. A long time ago, back when I was about 14 or 15 years old, in Junior High School, my shop teacher mentioned, in an off-hand way in class, that various curves could be described mathematically. I’d never heard that before, but I thought immediately, “This has interesting possibilities.” Moving ahead a few years, I discovered that I wanted to study and build my career around was the area known as Applied Mechanics, although it was a time before I first heard that term. In my freshman physics class, I discovered the laws of motion, and thought to myself, “This is great stuff! I can use math to describe how things move!” All of that happened back in the 1950s, and I’m still doing the same thing today (some might say I am in a rut!). As a teacher, I taught mostly undergraduate engineering courses, although I taught my share of graduate courses as well. It was the undergraduate courses that I liked most, because I firmly believe that the economy of a nation is strongly dependent on the quality of the baccalaureate level engineers produced in that nation. Engineers with graduate degrees are valuable as well, but the vast majority of the national engineering workload falls to BS level engineers.    Thus, I envisioned Mechanics Corner as a sort of continuation of the several undergraduate courses I most enjoyed teaching — kinematics, dynamics of machines, vibrations, and mechanics of materials. For the most part, I have stuck to the plan, so that most of the technical posts I have made have dealt with problems that I considered suitable for undergraduate engineering students, say perhaps, junior level. I have posted a few topics from my industrial experience, but those have been situations that baccalaureate level engineers would be expected to handle. Now I knew it would not be exactly like continuing to teach my classes. In particular, you would not have any homework or tests, and I would not have any grading to do – a win-win, or so I thought. I did hope, that even with no assigned homework, readers would take an interest in the problems discussed, even to the point of working through the details for themselves (I was terribly naive, apparently!). I knew from my own experience that the only way I ever really learned a new idea was to get in and work with it, work some problems, make some numbers, plot some curves, until I really understood what it was all about. I’ll venture to say that nobody ever learned any technical material simply by reading only. In actual fact, in the early days, I had one or two folks say that they would in fact work through the problems, so I was encouraged. What I was not prepared for, however, was the fact that the vast majority never seemed to even read very carefully, much less work through the problems! The questions that have come, and there have been a few, have largely been about matters totally unrelated to the posts. The most common question has been, “Suggest a topic for my final project,” which relates to not a single post. Needless to say, that aspect of my vision was totally unfulfilled. But there is another side. I ventured to write a few “philosophical” articles, items dealing with academic integrity and cheating, with how to ask for help, with how to write a report or a paper, and various other matters. I really thought all of this would be considered obvious and trivial, so I was completely unprepared for the excitement that some of these articles generated. There were, in some cases, many, many comments, and people seemed to really be interested. I’m left to wonder: why? Are these ideas foreign to the culture of India and SE Asia? Are these things not all taught at home and in the public schools? I don’t know, but there was a lot of interest in these matters. But Mechanics Corner was intended to be primarily a technical blog, and there, it just did not excite the interest of the readership. As time passed, there was less and less interest. First, the comments dropped off to just about zero, and later, there were fewer and fewer who even bothered to “like” the articles. Finally, the number of reads has dropped to almost nothing (there may be no one left to read this final note). Well, there could hardly be any more clear indication that it is time to stop. I asked for opinions about this from some of the administrators, and was told that the blog was just over the heads of the readership. That makes me sad; that was never the intent. If it is true, I do not see how engineering has a very bright future among this readership. Even so, I wish all of you the best for your careers. I hope that you are able to find rewarding and beneficial work in which you will be happy and make a real contribution to your societies. To use an old cowboy metaphor perhaps familiar to many of you from Bollywood, “It is time to hang up the bridle and saddle, and say, ‘Adios’ (Adios is literally, “to God”).  

DrD

DrD

 

A Problem in Statics & Dynamics, #34

Mechanics Corner
    A Journal of Applied Mechanics and Mathematics by DrD, # 34
    © Machinery Dynamics Research, 2015
A Problem in Statics & Dynamics     
    
Introduction         A problem was recently posted on this Forum, requesting help, that has led me to consider a somewhat more general problem for this post. The scope of this post will include the original problem, although not by the method required there, but will also go beyond to a more general geometry. We begin here by stating the present problem; interested readers are invited to search back for the original problem posted 19 December, 2016, by iivii.
    

Assembly Drawing, with Dimensions   StatDynProb.pdf

DrD

DrD

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