MECHANICAL OR AEROSPACE??
This was a question posted in quora. I posted my opinion based on my outlook on both of these streams. Whether one is better than the other depends on what is being considered as a common criteria for comparison. Let's start with scope. A person graduated with a mechanical degree can very well have opportunities to work in the aerospace sector. The aerospace sector is multidisciplinary and people from electrical, coding and other background can easily find work. But the other way is not so. An aerospace engineer is only familiar with the mechanical aspects related to aircrafts. You cannot expect this guy to easily get a job in a heavy machinery industry, for example. Next grade of comparison is payscale. It is obvious that aerospace is a better paying field compared to field. Here I am talking about the average salary per annum for both the fields. There may be mechanical jobs which pay more than a specific aerospace job. But on an average, aerospace job gets you more bucks. R and D. Once again this is a tough comparison. Both of the sectors are undergoing numerous innovations over the years. In case of mechanical, there are certain specific fields where R and D is more concentrated than other types of industries. For example, R and D in the automotive fields is much more compared to other types of fields. But for aerospace, every sub-sector is under constant Research and Development. Job vacancy is a big issue. And mechanical easily exceeds aerospace in terms of available job numbers. This is primarily because mechanical is a broad field. It can be divided into marine, automotive, heavy machinery, thermal, tooling, power plant, and hundreds of sub fields, each of them having numerous opportunities. Aerospace is only aerospace. To be more precise, aerospace is a specialization field of mechanical itself. So you can see the comparison. Better is a relative term. The grounds of comparison matter a lot. So choose your interest carefully, and don't regret later!
ayushman dutta
WHICH DESIGN SOFTWARES ARE USED?
A single software is not used in all the industries. Softwares these days are highly customized based on the specific industrial scope. Gearbox based industries use KISSSOFT Software. Pro Engineer is used in a number of industries. Industries having a focus on Product Design use CATIA for rendering purposes. Solidworks is now catching up quickly. A lot of companies are adopting solidworks for component modelling and assembly. AutoCad is used for drafting purposes and production drawings, blueprints. Generally tool drawings of jigs and fixtures are done in AutoCad. Autodesk Inventor is also used along with Solidworks. However lot of professionals are admitting that assembly features are much better in Solidworks.
ANALYSIS OF A SIMPLE GEARBOX
ANALYSIS OF A SIMPLE GEARBOX Based on a simple project, we found out the most vulnerable regions in a gearbox, considering a helical gearbox, 2-stage, supported by ball bearings and used in an agitator drive. # Static analysis of Geared pairs: The power transmitted between geared pairs exerts a force on the point of contact. The point at which the forces are the maximum and a general trend of the variation of forces with the tooth profile is necessary for determining backlash. EQUIVALENT STRESS DISTRIBUTION EQUIVALENT STRAIN DISTRIBUTION # Static analysis of Output shaft: This is the shaft subjected to maximum torque. Hence it is subjected to maximum bending moment due to the weight of the gears as well as torsional force due to the gear fixed to it. This is the most critical shaft and is more prone to failure. EQUIVALENT STRESS DISTRIBUTION EQUIVALENT STRAIN DISTRIBUTION # Load analysis on bearings: The bearings are responsible for housing rotating shafts. The overhang, the revolution speed and the weight of the shafts and the gears being housed influence the bearing life and chances of bearing failure. EQUIVALENT STRESS DISTRIBUTION EQUIVALENT STRAIN DISTRIBUTION In the Gear analysis, the maximum stress is at the tooth profiles which are at immediate contact for a short instant. The maximum stress is less than permissible values [evident from the absence of red regions]. The other regions have lesser stresses. Similarly, the maximum deformation is at the point of contact at the teeth. This proves that the maximum stress and strain is experienced at the instantaneous point of contact at the gear mesh. In the output shaft, the torsional stress dominates bending stress due to output shaft and gear. The yellow regions at the bearing supports are due to the bending moment at those points due to the overhang. The blue regions at the centre regions are due to the self weight of gears and the torque of the gear. The deformation is maximum at the centre regions, marked by red zones. This proves that the most critical region portion of the shaft is the gear portion due to torsional stresses. In case of bearings, the stress is within permissible limits. The stress is more at the inner ring due to a less diameter. However in case of deformation, the backward region of the bearings is marked by red regions. This indicates that more balls are needed for the ball bearing, or that the ball bearings must be replaces with cylindrical rolling contact bearings.
ORGANIZATION BEHAVIOUR IN "THE SOCIAL NETWORK"
ORGANIZATION BEHAVIOUR PORTRAYED IN THE SOCIAL NETWORK The objective of the article is to select a movie which portrays a number of topics that have been taught to us as the part of a course known as organizational behaviour. The movie is an amalgamation of lots of qualities and aspects we face in an organization, or rather in the process of building up an organization. Keeping knowledge of them is beneficial for the development and well-being of the company. As an organization grows in terms of employee strength, annual turnover and expansion of business domain, such factors have more and more influence on the same as a whole. With the help of the movie “The Social Network”, it has been an aim to explain these factors in an elaborate and realistic manner, since the movie is based on a real story. The movie is appropriate when it comes to the influence of elements of organizational behaviour in a blooming start-up. The social network is based on the achievements of Mark Zuckerburg, who chose to drop out of his University in order to focus on an idea; which would later become renowned worldwide as Facebook. The role of mark was reprised by critically acclaimed Jesse Eisenberg and the film, days after its release, was showered with notable acclaim. A number of such rave reviews have been mentioned below: The Social Network, directed by David Fincher, begins as it ends, with Zuckerberg (Jesse Eisenberg) looking unreadable. He’s sitting in a Harvard bar, drinking beer and struggling to make eye contact with his girlfriend Erica (Rooney Mara). She’s pretty, articulate, quite a catch for a curly-haired, rubber-faced guy like him. Soon they squabble, mainly about his obsession with Ivy League private clubs, to the point where she says she’s leaving him. -----The Telegraph UK [Source: https://www.telegraph.co.uk/culture/film/filmreviews/8064694/The-Social-Network-full-review.html] “The price of that ambition, at least as dramatized here, is borne by those around Mark, who remains a strategic cipher throughout: a Facebook page without a profile photo. Charmless and awkward in groups larger than one, he rarely breaks into a smile and, if memory serves, never says thank you. He seems wary at some moments, coolly calculating at others: when his eyes haven’t gone dead, you can see him working all the angles. One of those angles, according to Mr. Sorkin’s script, which follows the outline of “The Accidental Billionaires,” Ben Mezrich’s book about Facebook, was one of the site’s co-founders, Eduardo Saverin (a very good Andrew Garfield), a fellow student of Mark’s as well as his first big check writer and personal chump.” ----The New York Times [Source: https://www.nytimes.com/2010/09/24/movies/24nyffsocial.html] LEARNING POINTS MOTIVATION: Mark was snubbed at by his contemporaries. His peers would have unlimited access to Ivy League clubs and bachelors parties. Being a nerd and socially awkward, he struggled to socialize with people, specifically with women. This led to a general brooding to his girlfriend about his desires to be in such places. When dumped by his girlfriend to the incessant brooding, he becomes angry. When a girl expresses her distaste in talking to him in a party where he struggled to get in, his frustration transcends all bounds. The underlying factor here is the motivation. The idea of Facebook is to connect to people without the need to interact face-to-face. As more and more people resort to this type of socialization, the need for face-to-face interaction is loses its value. The movie has a particular scene where he utters that more the popularity of Facebook, more will people be convinced that actual physical interaction is not relevant in making friends. The motivation of doing something new in order to bring in a new trend has been portrayed in the first picture. PERCEPTION: The second picture shows him watching a person in a cold and calculated manner. It is difficult to read the expressions, due to which it is left to viewers’ opinions. The person in his sights is his university mate who belongs to a socially upper class and has the resources to lay the foundations of Facebook. The perspective can vary based on interpretation of the gesture. One can say that mark harbors a hidden disgust and envy against his friend, since he is rich and has resources. It can also be deducted that he is reading the movements of the person to understand whether the person would serve to be a long-term investor, should Facebook grow exponentially as a big company. Another point that can be inferred is that Mark is an impatient guy and does not care about the rambling of the person, showing a certain lack of gratitude. From time to time in the movie, a certain lack of gratitude has been portrayed as a characteristic of Zuckerberg [he forgot to utter thanks unless memory served him]. The expression displayed in the second picture is a perception of the many thoughts going on in the mind of the protagonist. LEADERSHIP: Leadership is willingly or unwillingly adopted by a person who is on the verge of founding a mammoth organization. Without the quality of leadership, it is difficult to properly run an organization. Leadership has a positive and a negative side. The positive side acknowledges the grievances of each and every employee and strives to eradicate them. The negative side of leadership simply does not entertain the opinions of employers who are at the bottom of the hierarchy. Sometimes, it is helpful to have a positive view on leadership; sometimes being strict on the employees helps in finishing tasks before the deadline. In the picture, Mark explains the potential of his idea in the upcoming decade. The manner in which he acknowledges the people who are willing to invest in his idea is one of attention. The proper use of the correct sides of leadership to the employees, investors and competitors is something that requires skill and experience. AMBITION: There is a significant difference between a person rusticated from university owing to bad grades and a person who willingly drops out of college in order to pursue his dreams. Every start-up and organization is founded by a person or a group of people who were willing to take the risks in order to follow their dreams. Mark has never been depicted as having any interests in the academic curriculum and the conventional methods employed in universities. He had an idea; and knew that it required a knowledge which regular classes would fail to provide him. Motivational support was not something he expected from his university. The picture shows how much he valued his dreams, enough to leave university studies and work on the idea which would set a new worldwide trend.
REVIEW PAPER ON FUSELAGE OPTIMIZATION OF AN U.A.V
FUSELAGE OPTIMIZATION FOR AERODYNAMIC LOADS DURING FLIGHT THE MAIN OBJECTIVE OF FUSELAGE OPTIMIZATION IS FOR THE FOLLOWING PURPOSES: [1] During flight, the entire fuselage of the RC aircraft is subjected to loads (dynamic). These aerodynamic loads affect the fluid flow boundary around the entire plane, which can affect the governing factors of flight like lift, drag, stalling angle, cruise velocity. [2] The distribution of aerodynamic loads around the fuselage can affect the control surfaces. The roll rate for a certain angle of aileron deflection at a certain angle of attack is fixed. These loads can affect the angle and deflections. Hence it is necessary to know these load distributions. [3] The fuselage shape must be made keeping the aerodynamic loads in mind. The no of support structures to be added: gussets, bulkheads, stringers, Longerons are calculated based on the pressures at each point. GENERAL FLOWCHART FOR DEIGNING OF AN AERIAL VEHICLE WHAT DOES OPTIMIZATION INCLUDE? The optimization process consists of the following stages, chronologically. Preliminary design sketch Aerodynamic mesh panel The surface of the design is divided into a number of panels. An equation of the flow potential at the surfaces and velocity potential at the intersecting points is done. The load due to the pressure distribution is directly related to the potential at these mesh panels. The unknowns are grouped under a single matrix of co-efficient. They can be further extended as a system of linear equations which when solved help in calculating the disturbance potential and then the individual velocities at these points. These velocities can be used to find the aerodynamic pressures. Having multiplying these with area of a single mesh, the forces can be calculated. Using a coupling method between the aerodynamic model and structural model, the forces can be added as parameters to the structure to calculate the displacements on the fuselage. Accordingly, the sizing of the fuselage can be done to determine the necessary shape. AERODYNAMIC PANEL MESH Calculation of aerodynamic loads at each point The loads are present at each mesh of the surface. The aerodynamic pressures are found out as a function of the mesh area. Structural sizing to reduce these loads At a certain angle of attack, attitude, acceleration of the aerial vehicle, a flight condition is calculated by taking the load factor into account. These variables are then put into account and the resulting deflection required for the control surfaces are calculated. This is termed as the trimmed condition of the aircraft. The trimming may also include more design parameters, each of which is added as a constraint and subsequently coupled with the load factors to repeat the above process. These are the static and trim loads. During dynamic flight conditions, the velocity potential and flow potential shifts around turbulent regions or gusts. The procedure for calculation of the aerodynamic loads is similar, where the boundary conditions are assumed to be harmonic in nature and the singularities considered for a solution to the equations are doublets (Multiple solutions for a single constraint equation). Every dimension is taken as a displacement constraint. The no. of load cases for the entire structure is taken into account. Since each dimension is affected by all the loads, these values are multiplied to get the total number of constraints. In the first case, 5 dimensions have been considered for constraint. 50 load cases have been determined. Therefore, TOTAL CONSTRAINT= DISPLACEMENT CONSTRAINT X LOAD CASES = 50 X 5 = 250 Structural design (adding of support structures) The design variables for the fuselage are stringers (thickness, length), skin cross section, skin thickness, position of bulkheads at the centre part of the fuselage. More the support structures more will be the design variables. The idea is to reduce the mass of the aircraft and place it exactly where the aerodynamic loads will be the maximum during static and dynamic flight conditions. The support for the rear end of the fuselage can also be determined depending on the bending. The shear forces acting on the walls are similarly taken into account. Apart from the minimization of mass, another objective is to keep the manufacturing ease in mind. The final dimensions for the fuselage structural components must not be difficult to build and the assembly should be easy. Structural FEA. Finite element analysis of the final structure of the entire RC aircraft is done. DIFFERENCE BETWEEN A FEA DESIGN AND AN AERODYNAMIC DESIGN. NOTE THE SPLINES IN THE AERODYNAMIC MODEL WHICH DENOTE THE OPTIMIZATION SOFTWARE: LAGRANGE is a software which is used for Multidisciplinary Design Optimization (MDO) of aircraft structures.
INDUSTRIAL VISIT IN I.S.R.O- A COLLEGE TRIP
AN INDUSTRIAL VISIT TO INDIAN SPACE RESEARCH ORGANIZATION A CONCISE REPORT Satish Dhawan Space Centre, Nellore, Andhra Pradesh 13th February, 2018 About: The Satish Dhawan space centre is located in a small island off the coast of Andhra Pradesh (in the Nellore region). The justified reason for it being close to the coast is simple; the stages of the rockets fall on the sea. Secondly the thick smoke generated during the launch time encompasses a wide area. A launch pad cannot possibly be located in a densely populated area and a landlocked region. The space centre houses two launch pads, a huge Vehicle assembly Building, a mission control centre, a sound rocket facility and reservoirs for liquid propellants. The second centre is in Bangalore; where the solid propellants, satellite equipment and the components and stages of the rocket are manufactured. First Launch Pad: This is the older of the two launch pads, which was originally inaugurated by Sri. A.P.J Abdul Kalam. The umbilical tower is approximately seventy metres in height and the lower heat dissipation V-base has a depth of thirty metres. At a distance of about two miles from the first launch pad, the vehicle assembly building is located. The four stages of the rocket, assembled with the satellite at the summit is loaded on the troller and transported to the umbilical tower. The launch pad has four pipelines across four directions of the towers for provision of liquid propellants. The first launch pad was the launching zone for the GSLV satellites and the PSLV MK2 satellites. Second Launch Pad: The second launch pad is specifically chosen for the launch of the most recent development: the PSLV MK3 satellites. The second launch pad has a bigger reservoir of water for cooling purposes, which is only for the mentioned satellite. It is seventy six metres tall, and the V-base located underneath is only about six to seven metres in depth. Unlike the first launch pad, the second one here is portable, resting on a pair of rail tracks owing to which it can be moved back and forth. The troller carrying the assembled rocket need not transport much. The tower does it itself. The justification of a smaller V-base is the height compensation. The PSLV MK3 satellite having a height of only forty nine metres can be fixed much above. By the time the exhaust fumes hits the surface, a significant amount of heat has already been dissipated. It also has a higher number of vertical compartments, enabling a decreased loading and unloading time for the rockets. Both of the launch pads are heavily restricted with barbed wires and electrical fences. Mobile phones and similar electronic equipments are strictly prohibited within the zone. They are constantly monitored for unsteady weather conditions. Mission Control centre: The mission control centre is the brain of the Spacecraft. The space crafts launched upward are controlled and monitored from the mission control centre. It houses an array of workstations, each of them having an intercom radio. The live status of the launch is viewed from a panoramic wide screen at the front of the centre. The screen has a timer to count the time elapsed till the crash lf the first stage and the second stage. The mission control centre is similar to an amphitheatre. The back portion of the centre has a huge centre for accommodating audience. This is because notable launch events are witnessed by dignitaries like the defense minister, prime minister, cabinet of union minister and similar personalities. Vehicle Assembly building: The only place to be kept strictly off bounds from visitors is the vehicle assembly building. This is because the assembly of the spacecraft, including the addition of solid propellant stages of the rocket is done here. It is at a straight distance of two miles from the launch pad. The launch pad and the vehicle assembly building are connected by a straight unobstructed road which is used for transportation of the rocket in a trolley. The solid propellants added to the rockets are manufactured in Bangalore. Sound rocket facility: It is a facility which was not open to visitors. It was visible while the bus took a curved route from the launch pad back to the museum, marking the end of the trip. Museum: The museum has a number of laminated pictures, galleries and models of space crafts, the models that have been manufactured by ISRO over the years, a brief insight into space propulsion and rocketry. Mobile phones are allowed here and the museum is open to photography. On a concluding note, the trip was an enlightening experience for students. The theories which are taught in classrooms are actually applied here and put to good use. A simple trivial error in calculations, design, assembly, manufacture or any part can lead to pre-timed failure and burning of the rocket. With crores of rupees at stake, the risk involved and the margin of error is minimal and merciless. It is a lesson that the studies that are taught in college academics are crucial. - Ayushman Dutta
CONCISE CASE STUDY ON ZOMATO
CASE STUDY: ZOMATO INTRODUCTION: Zomato is a food and restaurant search engine which caters to the daily demands of people who are in search of good eating places. With the largest catalogue of restaurants around the globe, zomato is used on a daily basis to locate nearby restaurants. Moreover, it can also be used to book a table in a few selected restaurants at a certain time. It also has a consumer suggestion list which specifies the availability of a certain dish or cuisine at a certain time. It was started as a simple restaurant search and discovery service by two people: Deepinder Goyal and Pankaj Chaddah. Before the foundation of zomato, Deepinder Goyal was a management consultant for Bain and Company in New Delhi. It was at Bain that Deepinder conceived the idea of an online restaurant information service after seeing the demand for menu cards among his colleagues. BRIEF TIMELINE: 2008-The service began as "Foodiebay". November 2010- Foodiebay was renamed as Zomato. 2011-Zomato launched in Bengaluru, Pune, Chennai, Hyderabad and Ahmedabad and launched smartphone applications. 2013-The company launched in New Zealand, Turkey, Brazil, and Indonesia with its website and apps available in Turkish, Brazilian Portuguese, Indonesian, and English. April 2014- Zomato launched its services in Portugal. July 2014-Zomato made its first acquisition by buying Menu-mania for an undisclosed sum. September 2014-Zomato acquired Poland-based restaurant search service Gastronauci for an undisclosed sum October 2014-Zomato launched its services in Canada November 2014-It extended its reach to Lebanon and Ireland as well December 2015-Zomato acquired Italian restaurant search service Cibando. April 2015-Another round of funding for Zomato, led by Info Edge, Vy Capital and Sequoia Capital, January 2015- Zomato acquired Seattle-based food portal Urbanspoon for an undisclosed sum. The acquisition marked Zomato's entry into the United States, Canada and Australia, and brought it into direct competition with Yelp, Zagat and OpenTable. GROWTH AND POPULARITY: Database The numbers of listed restaurants has significantly increased over the years. With growing demands of food orders, restaurants have decided to register themselves under a single site for online orders. This gives an extra edge to the zomato, which has been built for this purpose. In 2008, 4000 restaurants have been registered under zomato. The number has exponentially increased. In 2013, the number rocketed to 94000. No. Of visitors As the no. of restaurants increased, so did the no of visitors in the official site of zomato. The site is constantly under development, making a more friendly and convenient interface for people to order food online from the nearest places. The no of online web viewers of zomato restaurants have increases from a few thousands in 2008 to more than a million viewers by the end of 2013. Revenue Over the span of five years, the annual turnover for zomato has grown significantly. Despite the fluctuations in the Indian GDP, the global as well as national income for zomato has always been double or triple to that of the total investment. The investment includes sales and advertising, Home delivery, maintenance of restaurants, etc. A GENERAL TREND OF THE REVENUE, ONLINE POPULARITY AND NO. OF LISTED RESTAURANTS CONCLUSION: This is the first review of the project (CASE STUDY OF ZOMATO). Hence we have only provided minimal information about the various aspects of the Indian start-up. However there are a lot of aspects which we have planned to cover as a part of the case study. On a concluding note, we have provided with a list of the aspects that we have planned to explain for the next part of our case study: · Global popularity · SWOT analysis of zomato · Revenue model · Revenue graph and annual trend · Upcoming Strategies and Alternatives
3D PRINTING OF UNIVERSAL JOINT: AN ACADEMIC PROJEC
3D PRINTING OF UNIVERSAL JOINT: AN ACADEMIC PROJECT A universal coupling/joint is used to facilitate rotation between shafts which are inclined to each other. The angle between the two shafts is called the operating angle. It Is generally, but not necessarily, constant during operation. In order to achieve perfect rotation, 2 joints are generally used with an intermediate shaft in between. The method used in making this joint was FDM 3D PRINTING. It is a rapid manufacturing method which can quickly make intricate and complex shapes which are otherwise, very cumbersome in case of conventional machining processes. 3D printing is used to manufacture the universal coupling as our project. The 3D printing machine used here is a FDM 3D PRINTING machine which uses ABS material. Considering the volume (in cc) of our entire assembly, the total cost (including taxes and cost of support material) was Rs. 811. The total time taken for the 3d printing process was approximately 5-6 hours, excluding the time taken to manually remove the support material stuck on the finished surfaces. The general procedure for the 3d printing of the universal joint involved the following steps: We used the Solidworks model of a universal joint and scaled down its overall dimensions. The dimensions were reduced proportionally in a manner such that the distance between the 2 extreme ends of the assembly does not exceed 5 cm. The design of the individual components and the overall assembly was submitted to the labin- charge of the 3d printing machine. The models were converted to .stl files and their net volume (in cc) and weight was calculated (for cost purposes). The machine calculated an estimate of 5-6 hours for the entire process. After the printing was done, we used sharp pins and needles to remove the support materials. Since it is a relatively small model, the support material were stuck and had to be removed, especially from the holes. Using drilling, the hole of the fork component was enlarged to properly insert the collar pin and assembling the other components. The miniature universal joint can be used to rotate small shafts which are not properly oriented to each other. It can also be used to support rotation between shafts which are parallel but not in the same level. This can be achieved by used 2 universal joints. Being made of ABS, there are lesser chances of rusting and chemical degradation by acids and abrasive chemicals. The total manufacture time required for the joint was 5-6 hours. For a universal joint of the size mentioned here, it would take much more time if conventional machining processes were used. The method can be easily used as an alternative to machining processes.
HOW ARE DESIGN CALCULATION DONE IN MECHANICAL?
Ever wonder how man-made things are the way they look like? Why does a bridge look exactly like this: Or why do tables have rounded corners like this: The thing is every feature in a design is properly calculated. Chances are, without the feature that seems to just add style, the object would simply fail to work in a proper manner. Before making anything, the design is first conceived and finalised. Having a properly calculated design and adherence to it while manufacturing the item is equally essential. But how to get started with "designing something"? Take any mechanical component for example, A bearing. Now the first part of the design methodology is to figure out the dimensions that must be found out. If you look at the above picture closely, you might see an inner hole, an outer ring and a thickness. That makes it 3 primary dimensions. The inner diameter. The outer diameter The length (thickness) of the bearing. The second part is the selection of the material. Its taken for granted that before the design, all the operating conditions have been given to you. The operating conditions gives a good idea of the stresses subjected to it. The next reason of stress are the forces acting on it while operation. You have to calculate these forces. Based on these two factors, you can select a relevant material from the design data book. If it is an actual industrial project, then you might take a look at the company catalogue and the materials inventory for material selection. Third, the check for safety. Having found the stresses and the material, the most important part is factor of safety. Setting a factor of safety depends on the component and the company producing. Some companies may use an FOS of 4–6 (especially gears) while some companies may keep it as much as 28–30 (chains and sprockets). Set a factor of safety and see if the calculated forces are less than the permissible value. If the latter is more, then it is an unsafe design. Unsafe design troubleshooting employs a lot of methods like: :- Change of material :- Change of the dimensions Addition of extra components similar to the none in question. And more… If you need a more clear view of design methodology, I suggest you to read :- Machine Design By R.S Khurmi :- Design of Machine Elements By V.B Bhandari These are a few of the many books available. Hope you got an idea of the approach for component designs!
CUSTOM PAINTING
TURNING OLD SOUVENIRS INTO PRICELESS ARTICLES Family photos are not something that you throw away when they become old. They are more than articles; they are fragments of memories passed down among generations. When these pictures turn yellow with time, people resort to different ways of renewing it. Who would not hesitate to dump an old family picture into the store room?! Some moments do not repeat themselves, and the photos taking during these times are all that a person to reminisce his memories. Collecting these photos into a single album, making a collage out of these pictures and further laminating it, digitally saving them in storage devices are some of the ways of immortalizing these old souvenirs. Turning these family photographs into evergreen articles is convenient in a number of ways. They can be gifted to family members during special occasions; they can be kept close to self and taken along with luggage without any fear of getting crumpled, torn or damage. These articles would adorn the home. They can be kept on dining tables, living room tables, hung up on walls for people to feast their eyes. There are numerous ways of putting them into use. The pictures are very valuable pieces of memories; we all know how agitated our parents and grandparents become when they cannot find the photos of their younger days in the shelf where they keep it. Similarly, we get surprised and happy whenever we take out a children’s book from the old basement in our house and a small picture of our childhood falls from one the sides. Children, on finding pictures of their parents when they were young quickly ask them about it. These photos always evoke a sense of nostalgia; a sense of the old days which would never come back. The only thing that can be done is cherishing them and making them unforgettable by preserving of the photographs. We have made a list of the most recommended methods of preserving old family photographs. Preserving them in a way such that they remain intact even after a long time is an essential work. Besides there is practically less hassle involved in the preservation of such pictures. Sleeping Pillows and Bedsheets: Pillows and bedsheets are the companions of sleep, and without them night becomes so uneasy and uncomfortable. So why not decorate these midnight companions with photographs that would always make you smile whenever you see them? Artistic bedsheets, drawing based pillows are available on online shopping portals. Bedcovers and pillow covers are also customizable and can be decorated with different art works and sketches. Plain pillows are just not preferred now and artworks have become a necessary addition. Adding to beds and pillows, sofas, divans and lounges also come with a variety of options for customization by addition of paintings and sketches. Generally customers purchase a pillow and numerous pillow covers with diverse sketches, using one each day to make it seem less monotonous. With custom paintings coming into play, old pillow covers can be made to look new by printing family pictures or your favourite pieces of paintings. Other than printings, favourite art works can also be sewn into bedsheets. We can always relate to childhood memories where our grandmother would sew shapes of flying animals, picturesque sceneries into old bedsheets and make it completely adorable. Sleeping pillows and bedsheets are one of the many ways where we can affix family photographs for the sake of making more priceless and desirable. Daily reminders: The best example of attractive calendars is the corporate calendars. Every month is accompanied by a fresh face, or a new quote, or a different scenery from the previous month. To add to the variance, the fonts and the colours change in each page and the month. In college calendars, new faces accompany every new month. In tourism based calendars, every new page consists of a month and a beautiful piece of scenery, where the scenery varies in each month based on the season during that month and the corresponding scenery during those times. Winter months like December have pictures of snowfall whereas summer months like May and June have pictures of cracked land and thick sands. The concept of calendars also extends to families. As gift presents, families are often presented with calendars where every month corresponds to a photo of a member of their family. To add to the innovation, every month is accompanied by a picture of the important events to be happening then. If February is the month of anniversary of any member, then that month will have a picture of the couple exchanging wedding rings. If November happens to be the month of someone’s birthday, the month will feature a picture of the member’s selfie with birthday cake in the background! Such family calendars can be easily procured by relevant calendar printing services. The idea of gifting these calendars is very unconventional. Not only family based, the calendars can also be customized on the basis of the occasion. Couples can be gifted with couple calendars, where each month marks their favourite moments experienced during that month. For example, if they proposed each other on the month of October, the month can have a photo of one proposing to another. If they had their first child in the month of July, the month can have pictures of them holding their first child. Family calendars can be infinitely customized. These family based custom calendars add flavour with the fact that you would never forget important dates. All the important occasions are red marked on the calendar. Besides, it makes the calendars much more personal. If you were born during the month of September, won’t you love to have a calendar where the September month page features your photograph on the cover! Photo collections: It is a nice idea to spend leisure time searching through the entire house for old photographs and bringing them together into one place. Finding these pictures and then attaching them into a single notebook is a safe way to ensure that they never get forgotten somewhere. It is from here that the idea of an album originated. Albums are an integral possession in almost every home; every family has an album that has been passed down from ancestors. The best part is that these albums are not constant and photos are constantly added here; photos worth preserving as a memory. Albums are also gifted during special occasions. During birthdays, the person is often gifted an album of all the best photos that were ever taken of him. During wedding anniversaries, couples are gifted with albums where their favourite photos are featured. Similarly family albums also serve the same purpose of preserving special moments; those that would never come twice. Along with photos, the idea of gifting collages is also a fine idea. Collages are also similar to paintings to respect to the fact that they are collection of the most featured paintings. But the appearance of an album and collage differ on a number of aspects. Based on individual choice and the type of occasion, people can gift collage or they can gift photo albums. The only difference between collages and picture is that collages are a huge puzzle having all the photographs in a single frame. Some pictures are big while some appear small. Altough it seems a very appealing, all the pictures cannot be fit into a single frame without compromising some of their individual frame sizes. The collages can be hung on walls like simple paintings whereas photo albums cannot be used as wall paintings. Whenever you feel bored, try collecting old family photographs and try making collages and paintings out of them! Magnet chunks: These small chunks are available in different shapes like circular, rectangular, oval, elliptical and triangular. With a magnet attached on one side, these chunks can be attached to metallic walls, desktop cabinets, cabins, and tabletops. The non-magnetic side of these chunks is usually printed with a photograph of the choice of the person owning it. These chunks serve to be a cool and delightful sight for onlookers. They can be strip off and fixed anywhere, as long as the surface is metallic. The trend of converting family photos into magnetic chunks is increasing these days. The chunks are extremely cheap and the photos can be easily undersized and printed on the non-magnetic sides of the compact chunks. They are durable and unless tampered roughly, they last for a long time. Even if the chunks are damaged, the compact picture can be taken out and fixed on a new chunk. The pictures can be permanently printed on the chunk surface, or they can be simply put on top, provided the picture is on a small sheet of paper. Not only family photographs, emojis, cartoon characters, cool one-liners and anything you like. The most interesting part about these chunks is that they are eye catching figures. Whenever you open the fridge, or the cabinet to take out something, or the bookshelf to search for a book, or the door to enter your room, the first part that gathers attention are these small pieces of attraction. If not needed at the current moment, they can be stored inside boxes, although it is much better to keep them attached to any overlooked region of walls (as they tend to lose the magnetism when kept idle). Put up one of these outside your home doorbell and you will always see people entering your house in state! Ornaments: Ornaments and jewelry are the most promising articles that can be customized by addition of small photographs. The addition of photos increases their value as well as their appearance much more. A plain ornament without any small touch of personal emotions is only a dull piece of expensive metal. It may look costly but it lacks the personal touch; and the personal touch is furnished by these tiny photographs. Along with paintings, the ornaments can also be carved to get beautiful shapes. Like paintings, carving ornaments makes it a valuable artifact. But since the carving process takes away portions of the semi-precious metals, carving is not preferred as it decreases the monetary value. Paintings, on the other hand have no such issues and do not affect the monetary value of the jewelry. Small paintings done in miniatures chits of paper or cloth can be attached firmly to them using adhesive or by pressing hard. They can also be strip off when not needed or when a new painting is to be attached, as a single painting being attached for a long time can make it a dull sight to behold. Jewelry can adorn various parts of the body: neck, arms, legs, torso and head. Each of them have a dedicated type and category of jewelry, and the paintings for every type of jewelry differ based on how appealing they would look. Turn the dull pieces of expensive stones into valuable belongings!
GATE ME: BOOK SELECTION
This is a post for aspirants of the GATE examination who are about to give the ME (Mechanical) paper. To learn a topic, or an entire chapter, there are three ways to which students resort: :- Video Lectures :- Teacher/Faculty :- Books While all of them have their own share of pros and cons, this post is focussed on the importance of books in the concept building stage. A lot of students complain about books being incomplete, or deriving formulae in a haphazard manner, making it difficult for students to understand key chunks of concepts in a clear manner. This brings us to the topic of book selection; choosing the right book for a subject can be very crucial, to the extent that "thoroughly reading" the book line by line might solve all of your doubts. Mechanical engineering is a broad domain that is sub-divided into a lot of topics: fluid mechanics, thermodynamics, machining processes and more. The thing is there are countless book available and going through all of them is time consuming. When you are selecting a book for a specific topic, keep in two thing that must be properly covered in the book: Concepts Concepts generally consists of: Derivations: A lot of books do not cover derivations properly. The assumptions and the procedure must be clearly outlined in the derivation such that you can find out the result on your own. In case of examinations remembering all the results become difficult and in such cases, knowing the basis of the derivation becomes crucial (For example the shear force and bending moment expressions for prismatic beams under different loaded conditions). Diagrams: Derivations and results are further understood with the help of diagrams. The diagrams should have a proper labelling, and the notation used in the derivations should be used in the diagrams too (For example in turbomachinery fluid velocities, impeller blade velocities have a notation of c1 and u1, but if the diagram uses a different notation, it will be a big confusion). Graphs: Results are meaningless unless they have graphs which depict the nature of the variations between parameters. A lot of times, a simple look at the graph is enough to recollect the results (In heat Transfer, conduction in a wall with no internal heat has a linear profile, while the presence of internal heat generates a parabolic profile). Summary: Not a mandatory feature in a book, but having a summary at the end that enlists the important results is very helpful. Numericals (Solved and Unsolved) Solved numericals: Solved numerical have two advantages: One is they underline the application of the concept that has been derived; second is they have a stepwise solution. If you want to have a try at solving them, then you know that the entire solution is at your disposal, not only the answer. A lot of times it becomes difficult to find how some answers are written as correct in the book. Having a solved solution caters to this problem. Unsolved numericals: Good for practice. Plus, it is better if there is a variety of problems. A number of times, students skip derivation based questions or ones where we have to find out an expression. Do not avoid these questions. They are as equally important as objective numericals. Generally the most apt way is to refer to two books for a single topic; one that would have a great conceptual explanations in the form of diagrams, graphs, derivations (A lot of books do not cover derivations properly) and a book that would have lots of problems for practice and understanding. Here are the topics and the books prescribed for each of them: Engineering Drawing: K.S. Rangasami Engineering Maths: Differentials: Schaum Series, Kreyzig, B.S. Grewal Complex maths: Schaum Series, Kreyzig, B.S. Grewal Linear Algebra: Schaum Series, Kreyzig, B.S. Grewal Numerical Methods: Schaum Series, Kreyzig, B.S. Grewal Engineering Mechanics: Concepts: Beer And Johnston Problems: R.S. Khurmi Thermodynamics: Concepts: P.K. Nag Problems: Cengel and Boles Materials Science: Concepts: William D. Callister Strength/Mechanics of Materials: Concepts: Beer And Johnston Problems: James M. Gere Mechanics of Machinery: Concepts: R.S. Khurmi Problems: S.S. Rattan Fluid Mechanics and Turbomachinery: Concepts: S.K. Som Problems: R.K. Bansal Thermal Engineering: Concept and Problems: P. K. Nag Machine Design: Concepts: V.B. Bhandari Problems: R.S. Khurmi Manufacturing Processes: Concepts: Michael P. Groover Heat Transfer: Concepts: Yunus. A. Cengel Problems: P. K. Nag Industrial Engineering: Concepts: O.P. Khanna Please note that there are lots of books for a single topic and do not restrict yourself to only 2 books per topic. The books suggested here are suitable only according to my opinion. The best suggestion is to go through the recommended books for a topic and decide on what’s best for you. If you are in college, have a look around the library. That will give you an idea. As for how I got these suggestions, part of them are books I referred to during my semester exams (and still following for preparation of GATE ME 2019) and the other part have been suggested by the teachers at my coaching institute. If you have any other book in mind, please feel free to suggest. Constructive criticism is always welcome.
AGITATORS-WHAT THEY ARE AND HOW THEY CAN BE MADE B
AGITATORS-WHAT THEY ARE AND HOW THEY CAN BE MADE BETTER An agitator is a shaft mounted with impellers which is inserted into a tank. On rotating the shaft using a geared motor or a gearbox, the fluids inside the tank undergo a mixing process. The profile of the blades, the number of blades, the mounting of the shaft and the shaft dimensions are determined by the properties of the fluid to be mixed inside the tank and the batch capacity. Mixing Tank: It is a closed space of either cylindrical or cuboidal shape with opening ports for entry of fluid to be mixed. Mixing tanks are identified by their batch capacity, noted by V. Impeller: It is a blade with an aerodynamic profile used for creating turbulence on rotation. This is responsible for mixing of the fluid. The impeller is also referred to as the agitator. Agitator Shaft: The shaft holding the agitator during operation is termed as the agitator shaft. It is also the output shaft of the gearbox. Gearbox: It is an arrangement of gears meshed in pairs which used reduces the rpm of the geared motor, increasing torque. The gearbox is connected to a geared motor with a constant input rpm. Baffles: Baffles are restrictions within the fluid tank. These restrictions increase the turbulence of the mixing process, reducing load on the agitator. Based on the position of the agitator mounting with respect to the mixing tank, there are three types of agitators: Top entry agitators: The above diagram shows a top entry agitator. Here the shaft enters the mixing tank from the upper direction. Bottom entry agitators: opposite to the top entry agitator, the bottom entry agitator enters the mixing tank from the bottom. Side entry agitators: The shaft enters from the lateral direction of the mixing tank. SIDE ENTRY AGITATOR The excessive fluid pressure in an industrial mixer causes wobbling of the impeller shaft which leads to its failure. It also causes damage to the gearbox to which it is connected, leading to frequent need of maintenance. The unwanted effect generates a lot of stress on the mounting of the gearbox. In worse cases, the brackets also fail leading to gearbox dislocation within the mixing chamber. The other factors affecting the longevity of agitator gearboxes are the stiffness experienced by the support bearings and housing bearings and the improper meshing of gear teeth, creating an unbalanced load distribution on the gears. Such factors are to be taken into account while designing a gearbox specifically required for driving the impeller loaded agitator shafts in the industrial mixers. A number of points have been found out to be given significantly less preference during the design, analysis and optimization of the gearbox components as well the whole assembly. [1] Consideration of suitable kinematic arrangement of geartrain. This includes the position of intermediate shafts and their distances from each other and the location of support bearing bearings and gears mounted on the shafts. [2] Stress concentration methods have not been fully implemented for the output shaft of the gearbox which holds the impellers. Undercuts and notches have not been considered. [3] The orientation of gearbox mounting affects the stress and the weight subjected to the mount. The type of gearbox mounting position and the subsequent stress on the brackets/mounts must be taken into account. [4] During static as well as dynamic loading, the housing undergoes forces which may end up leading to cracks in it. Generally the design of the housing is performed based on the static loading distribution. However, when the gearbox is in operation, the dynamic forces are also in effect. Hence they must also be factored into while designing the casing of the gearbox. [5] For cylindrical mixers, baffles are used in order to add restrictions to the fluid flow path, thereby creating more turbulence and hence better mixing. Hence the load on the agitator is decreased by a small percentage. This must be subtracted from the net power to be transmitted by the agitator shaft. On a concluding note, agitators are a vast topic and deal with numerous laws of mixing and agitation. This article serves as a briefing of the mechanical component used in the industry.