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A Journal of Applied Mechanics and Mathematics by DrD

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A Comment Remembered

Mechanics Corner     A Journal of Applied Mechanics and Mathematics by DrD     © Machinery Dynamics Research, 2016 A Comment Remembered          Recently, in connection with one of the posts on Becoming An Expert, one of the ME Forum readers made a comment to me, something about seeing everything in terms of differential equations. That comment brought to mind a comment made to me many years ago that I want to pass along to you today.     Most of my college education was at th

DrD

DrD

 

Becoming An Expert -- Part 2

Mechanics Corner     A Journal of Applied Mechanics and Mathematics by DrD     © Machinery Dynamics Research, 2016 Becoming An Expert -- Part 2      Introduction     In the previous article on How To Become An Expert, I covered a lot of points in generalities with some short anecdotes from my own experience. In this article and the next, I will describe in considerably more detail a critical period in my own formation, an time of considerable professional embarrassment w

DrD

DrD

 

How To Become An Expert

Mechanics Corner     A Journal of Applied Mechanics and Mathematics by DrD     © Machinery Dynamics Research, 2016 How To Become An Expert      Introduction     This is going to be another of those personal experience/opinion pieces, so if these bore you, be warned! This may be the time to click on something else.     A reader recently wrote to me asking how to become an expert. I have to tell you, I don't spend much time thinking about being an expert, but I suppose o

DrD

DrD

 

#28 -- Analytical Design -- Part III

Mechanics Corner     A Journal of Applied Mechanics and Mathematics by DrD, # 28     © Machinery Dynamics Research, 2016 Analytical Design -- Part III      Introduction     In Parts I and II of this series, we began looking into the design analysis for an emergency steam cut-off valve for a nuclear power plant. Part I simply posed the problem, and Part II got into the detailed kinematic analysis of the four bar linkage that is to control the motion of the plug as it shut

DrD

DrD

 

John Deere & Culture Shock

More than once, I have remarked in this blog about the lack of participation. I have been mystified by the lack of questions and comments on my articles. Even those that get several thousand views, often have no comments at all. I just don't understand it! Yesterday, I had a visit. My visitor is a former student of mine, a fellow that I taught back in the early 1980s. His name is Bob, and Bob was an Ag Engineering student, if I recall correctly. He took my theory of machines class as an ele

DrD

DrD

 

#27 -- Analytical Design -- Part II

Mechanics Corner     A Journal of Applied Mechanics and Mathematics by DrD, # 27     © Machinery Dynamics Research, 2016 Analytical Design -- Part II      Introduction     In Part I of this series, the problem posed was to apply, as far as possible, the available knowledge of mathematics and science to the design of an Emergency Steam Shut-Off Valve, to be gravity driven as in the sketch below, Fig. 1. The inlet and outlet for the steam flow are both specified to be 0.85

DrD

DrD

 

#26 -- Analytical Design -- Part I

Mechanics Corner     A Journal of Applied Mechanics and Mathematics by DrD, # 26     © Machinery Dynamics Research, 2016 Analytical Design -- Part I      Introduction     On ME Forums, there have been a number of questions raised about design. Many students are writing in asking for ideas for a senior design project, others are asking for help with a design problem, etc. There has been some discussion about "Just what is design?" That was definitely a question in the min

DrD

DrD

 

Professional Societies -- Or Not?

Mechanics Corner     A Journal of Applied Mechanics and Mathematics by DrD       Machinery Dynamics Research, (c)  2016 Professional Societies -- Or Not? Introduction     This post is written in response to questions raised by one of our regular participants, a young engineer in Australia. What I have to say here is based entirely on my own, very American, experience, and others may have different ideas. I would encourage a general discussion in the comments, so that we may see

DrD

DrD

 

War Stories

Mechanics Corner     A Journal of Applied Mechanics and Mathematics by DrD     © Machinery Dynamics Research, 2016 War Stories -- Dr. Jack Levedahl Today I want to tell a few war stories, war stories in the literal sense of the word, in that they all relate in one way or another to World War II. They all center on my friend Dr. Jack Levedahl, a most excellent mechanical engineer and adventurer. Jack was an elderly man when I first met him about 15 years ago, and he has since passe

DrD

DrD

 

#25 -- A Textbook Statics Problem

Mechanics Corner     A Journal of Applied Mechanics and Mathematics by DrD, # 25     © Machinery Dynamics Research, 2016 A Textbook Statics Problem      Introduction     In the course of each day, I visit many web sites, always keeping an eye out for interesting engineering problems. The problem that is discussed here is one such that came from an American site (more about that web site later). The problem was presented as a simple statics problem, and the poster was ask

DrD

DrD

 

Torsional Stiffness of a Shaft - Part III -- #24

Mechanics Corner     A Journal of Applied Mechanics and Mathematics by DrD, # 24     © Machinery Dynamics Research, 2016 Torsional Stiffness of a Shaft -- Part III         Introduction     The discussion in previous parts of this series has focused on stiffness (or compliance) estimates for various shaft geometries. There has been nothing said yet about joining parts together, although most readers will readily agree that integral (single piece) shaft assemblies are very rare

DrD

DrD

 

Torsional Stiffness of a Shaft - Part II -- #23

Mechanics Corner     A Journal of Applied Mechanics and Mathematics by DrD, # 23     © Machinery Dynamics Research, 2016 Torsional Stiffness of a Shaft -- Part II          Introduction          In the previous post of this series, a variety of shaft forms involving both solid and hollow sections were considered. A general approach was developed, applicable to various sorts of non-uniform shafts, but always subject to the provision that the variation in section was gradual; n

DrD

DrD

 

Torsional Stiffness of a Shaft -- Part I -- #22

Mechanics Corner  A Journal of Applied Mechanics and Mathematics by DrD, # 22 (c)  Machinery Dynamics Research, 2016 Torsional Stiffness of a Shaft -- Part I          Introduction          A shaft is a common machine element, used to transmit rotational motion and torque from one component to the next. It is clear that the length of the shaft must be sufficient to span the distance from the first component to the second, but what should the diameter be? The answer to this quest

DrD

DrD

 

Professional Responsibility — Do The Right Thing

Professional Responsibility — Do The Right Thing In Western culture, three professions are recognized. They are medicine, the law, and theology. The practitioners of these professions have long been accorded a special status in society in recognition of their special knowledge. The physician is expected to use his knowledge of healing only for good, and never to murder or maim a person. The lawyer is expected to give correct legal advice to his clients, to keep them free from legal entangle

DrD

DrD

 

#21 -- Rigid Body Rotordynamic Instability, Part I

Mechanics Corner     A Journal of Applied Mechanics and Mathematics by DrD, #21     © Machinery Dynamics Research, 2015 Rigid Body Rotordynamic Instability, Part I      Introduction     The rotating elements of machinery are usually balanced to avoid vibration which results in noise and fatigue damage. That said, perfect balance is not possible, and there are practical and economic limits to the effort that can be expended to balance machine components. Consequently,

DrD

DrD

 

#20 -- A Question of Stability (Revised)

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 un

DrD

DrD

 

Value Engineering

A toothpaste factory had a problem.  They sometimes shipped empty boxes, boxes without the tube inside. This challenged their perceived quality with the buyers and distributors. Understanding how important the relationship with them was, the CEO of the company assembled his top people. They decided to hire an external engineering company to solve their empty boxes problem. The project followed the usual process: budget and project sponsor allocated, RFP, and third-parties selected.  Six months (

DrD

DrD

 

Flying Fun

The URL below will take you to some amazing pictures and a story about the SR-71 aircraft. In my own opinion, this aircraft is some of the most stunning engineering ever done on earth. Enjoy the pictures and the story! DrD http://www.tickld.com/x/jaw/military-pilot-shares-the-most-amazing-story-ever  

DrD

DrD

 

How to Ask for Help

How to Ask for Help Throughout life, we all find ourselves needing to ask for help at times. Even the most rugged individualist will, at time, need help. You may need to ask a teacher for help, you may need to ask a fellow employee for help, or you may need to ask the boss for help. There are a few good ways to ask for help, and there are endless poor ways to ask. Make your request well, and there is a much better you will get the help you seek. Since I began writing for ME Forums, I have rece

DrD

DrD

 

Where Will I Find A Job??

Where Will I Find A Job?? As I read over the questions that readers post here on ME Forum and elsewhere, I sense a common theme in many of them. There seems to be a wide, dare I say almost universal, concern about where those currently in college will find employment after graduation. To a degree this is entirely understandable; we all wonder what is in our future. Even so, the level of anxiety that I sense in many of your postings strikes me as extraordinarily high. Let us consider this a bit.

DrD

DrD

 

The VEProject --- Shifted Levers --- A Critical Assessment

The VEProject --- Shifted Levers A Critical Assessment      Introduction     The subject of this article is the VEProject Shifted Lever video, as found at the following URL:   https://www.youtube.com/watch?v=8TniRMwL2Vg     The video shows a "Shifted Lever" mechanism, a device that appears to be perpetually off balance. It is presented as a perpetual motion mechanism, that is, a machine that will run forever without any energy input other than, perhaps, an initial push. This presentation c

DrD

DrD

 

Twenty One Rules for Tech Writing

Twenty One Rules for Tech Writing Introduction One of the things that has surprised me about the readers of ME Forum is the number of folk who want to publish technical papers. When I was an undergraduate (a very, very long time ago), publishing papers was the farthest thing from my mind. I knew that publishing was a concern for some of the faculty, but it was certainly no concern of mine! To my even greater amazement, most of those desiring to write want to write in English, even though this

DrD

DrD

 

Problems With A Blog -- Differences Between SI and CI Engines

As most of us know, the Internet is a fantastic resource for information. You can find information on almost any topic you can imagine by doing an Internet search on the appropriate keywords. The flip side of this capability is that you can also find mis-information on almost any topic because there is no one to monitor the Internet for correctness. Wikipedia is a classic case in point. Many of the Wikipedia articles are highly informative and very valuable. Some, however, are highly biased and

DrD

DrD

 

What/Where to Study -- Another Opinion Piece

What/Where to Study Introduction I do not have the definite statistics available, but it appears to me that the majority of the readership of ME Forums is made up of students, with a much smaller number of readers at other points in their careers. By far the greatest part of these students appear to be in India, with a number in Southeast Asia and the Middle East; there are of course a few folks scattered all over the globe. It has been very interesting to me to learn about all of you, to gain

DrD

DrD

 

Help!! -- I'm Looking For A Book -- Update!

For quite some time now, I have been looking for a book that just does not seem to exist anymore. The title and author are -- Title:          Secondary Resonance and Subharmonics in Torsional Vibrations Author:      Per Draminsky It was published in Denmark, around 1961, or so I am told. It seems that it was probably a monograph, a single extended article that filled an entire volume of a journal. If anyone know where this can be found, I would much appreciate help with it. If I can borrow it

DrD

DrD



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