Electrical Conductivity and Resistivity

I guess “conductivity” and “resistivity” are terms relatively simple to explain to the general public. Conductive materials conduct electrical currents easily, and resistive materials resist electrical currents. So what should an engineer know about these terms that the general public does not generally know? By knowing how they are defined, and knowing the difference between resistivity and conductivity, and resistance and conductance.

No, this is not about "Resistance: Fall of Man" game (image taken from Best Game Wallpapers).

Metal whiskering

Do you know that not only mice and felines grow whiskers? Metals do too! Surprise surprise! To system and electronic engineers however this is an unpleasant surprise, a nightmare that they wish never will happen in their products. This phenomenon gain so much attention that high tech companies such as Lockheed Martin and NASA are still trying to understand it.

The removal of lead from solders increases the chances of tin whisker occurring. The phenomenon of whiskering had caused multimillion havocs, including the false alarm of Millstone nuclear plant, Swatch watches recall and the lost of Galaxy IV satellite (image taken from The Guardian).

Windows 8 - Hibernate Option

It has been a rather long hiatus from my technical blog, so I wanted to start the year off with something light yet useful for the readers. Since I just got myself a new laptop, running on the dreaded Windows 8 instead of the familiar territories of Windows 7, I decided to share one of the frustrating encounters here as well as how to tackle it.

For some unfathomable reason, the Hibernate option is not available when Shut Down is selected. This has been a very useful option for me, especially when I do not want to shut down all my applications and restart them again when I call it a day. To have all those programs ready to work when I have the laptop boot up again is really time saving, and I just could not believe that Microsoft would just do away with it.

Sure enough, online articles started offering tips and advice as to how to get that option back. And it was as I suspected - Microsoft still had the option available albeit hidden off and not even a cursory glance through all option would tell you how to get it back. Posted here are the steps to enable the options.

When you go for shutdown sequence, the option of Hibernate is unavailable to the user. Once the following steps are performed, the option will be available to the user once more.

Pro/ENGINEER - making edges more visible

If you are a Pro/ENGINEER user who finds the fact that the model's edges are not easily distinguished and causing features hard to find, then you may try this option to make the edges more prominent.

A sample 3D model in the original settings (above), with the circled area zoomed in (below).

Bimetallic Coin – The Making

Singapore has just launched its third series of coins last month, with the $1 coin stealing the limelight with its bimetallic composition. A golden brown outer ring encased a chrome inner core, which in fact are respectively brass plated and nickel plated metal. Much as a coin calls to mind the buying and selling process, there are also engineering involved in the metallic item – the manufacturing of it.

The array of new Singaporean coins launched in June 2013, with the $1 bimetallic coin taking center stage in this article's discussion (images taken from Monetary Authority of Singapore website).

Indentation Hardness

Among the three hardness types shared in the previous article, indentation hardness is the one which most engineers are familiar with. In fact, I bet that the general reply to the definition of hardness matches that of indentation hardness so much so that they are interchangeable in most discussions. Even engineering textbooks seldom mention indentation hardness as a separate topic – it is instead discussed as a hardness topic without an in-depth subtopic on other hardness types. 

Ball indenter used for Rockwell hardness testing. Different macroindentation test methods uses different indenter geometry and measures different dimensions of the indentation geometry (image taken from Instron).

Indentation hardness quantifies the resistance of a sample to material deformation, plastic deformation to be specific, due to the effect of a constant compressive load of a sharp object, hence the term “indentation”. In this test, a specific indenter is exerted onto the test material until an indentation is formed, of which dimension is measured and determines the hardness in accordance to a certain scale. 

For engineers personally involved in testing materials, it would be important to understand that most indentation tests have specific load rate and specific dwell time (the period in which the indenter load is held without moving), but not all of them are so. 

Hardness - How Hard Is Hard?

It is quite easy to say that a piece of metal is harder than a block of rubber, but how hard is hard? And is a cast iron harder than a stainless steel sheet? How would one find out information about hardness when you are reading the material properties from a specification sheet? 

In fact, when I read more into this property, it is not as simple as we usually would have thought, seeing that we use the descriptive term daily in our conversation. It could be said that: 

Hardness is a measure of how resistant solid matter is to various kinds of permanent shape change when a force is applied.

Diamond - not only were they a fascination with the ladies, they were also a fascination of engineers. With its reputation of being the hardest substrate ever known, it could cut through almost everything else. So how would you define the hardness of a diamond? (image taken from Jonathan's Fine Jewelers)

Tiger Stone - Brick Road Laying Machine

Road paving is one of those physically tasking work in which not much could be automated. Or is it? For brick laying in those brick roads though, a Dutch industrial company named Vanku introduced a machine which could save time and transform the back breaking task into one of relative ease.

In comes Tiger Stone, a road-wide brick laying machine that looked nothing like a tiger and more like a film laminating machine. A road as wide as 6 meters could have 400 m² of the road completed within a day as opposed to the 75 - 100 m² completed, assuming that the same amount of people are working on the task, namely 2 operators.

Semiconductor Technology: Moore's Law

Just look at that brick handphone. Does it seem like it was ages ago that telephones started to become mobile? The first hand-held mobile phone is, infact, not even 50 years old yet. First to be introduced in 1973 and commercially available by 1980's to customers who could afford to buy it (costs about USD 4000 back then, which is equivalent to USD 9300 today!) and don't mind carrying a 1 kg extra weight in their briefcase/handbag.

By contrast, today's mobile phones costs and weights only a small fraction of the earliest brick mobile phone and packs more computing power and has more fuctions and capabilities than one could ever imagine back then. All this thanks to Moore's Law.

Windows Shortcut Key that Helps

Computer applications are no longer just a high tech tool but a necessity in the life of an engineer. For those born past the 80's, using Windows is a breeze, but not so for the seniors who have to struggle with the sudden influx of computers into their work life.

Image from DeviantArt's Rehsup.

Bear in mind that although computers seem to be around forever, they were only popularly employed in our work space, especially those of the engineering community, around the turn of the century, and not everyone get the chance to be in front of one as well. Most of my seniors who started working in Malaysia around the turn of the century had to take turns using a workstation which had to be shared among a few engineers. When I was in secondary school, PC was something which not everybody could afford or willing to buy.

What is the cost of...?

The Avengers had assembled, the Dark Knight is rising and Star Wars had ended, but all these doesn't have to be limited to the silver screen. Just as Titanic could be a lesson for an engineer, so could a few other big budget movies.

For one, if you are the project engineer in charge of estimating the cost of engineering such challenging items as those featured in the movie, how much would they cost? Interestingly, I stumbled into a couple of websites which considered those same questions and presented an estimation which was fun to read although their accuracy warrant further corroboration.

Image from Super-Team Family.

Gloss - Measurement of Gloss Part 1

As was established in the previous post, gloss is determined by the amount of light rays being reflected under specular reflection as opposed to diffuse reflection. The more rays reflected through the former method, the glossier the surface is. 

Taktik iPhone case designed by Minimal studio. The surface is described as glossy and although this image is (I suspect) a rendered image, the glossiness of the surface is still conveyed. For quality control, determining the item as meeting the expected gloss level is not acceptable through mere visual inspection (image taken from DesignBoom).

Gloss could be compared qualitatively by comparing reflection of an image off different surfaces. Surface exhibiting sharper reflection will be considered glossier. But this is only useful in a qualitative way, and only if both surface reflections are distinctly different. Different observant will have different sight and recognition capability as well, so this method is physiologically affected. This qualitative method will not suffice as a quality control method.

Gloss - A Perception of Surfaces Part 2

Unlike other physical measurements, gloss measurement is not as straightforward. But it isn't difficult either, once one understood how gloss is perceived and interpreted by the human eye.

Gloss is an aspect of visual perception of objects, and it is an attribute of surfaces. With this in mind, any material could be made to meet the requirement of any gloss level as long as the technology exists and the method economic. 

What in this picture makes you think that the car's exterior is "glossy"? What causes this term to come to mind? (image taken from Ziebart)

Gloss - A Perception of Surfaces Part 1

You take a look at the shiny metallic surface of a sleek sports car and you immediately thought of it as "glossy". You saw another car with a body which reflects none of the ambient lighting, absorbing everything like a black hole, and you think of it as "matte".

The glossy surface of an Audi TT (image taken from DeviantArt).

As easy as the word comes to your mind, how does one define "glossy"? This would be important to an engineer, since there has to be some way to control the quality of a surface, and control will not be possible without measurement, and no measurement without a solid definition.

Analog vs Digital

One might have easily heard this hundreds of times - "We are now entering the realm of the digital age" or something along that line. What does that mean, and how much did "digital" influence our life?

To put it simply, a digital system presents data by using discrete or discontinuous values. In other words, there are only yes and no, 0 and 1. Or it may be 1, 2, 3, 4 and so on, but nothing is envisioned or accepted between the numbers, so there is no such thing as 1.4 in a discrete system. If the system is 1.1, 1.2, 1.3, 1.4 and so on, then 1.27 is not accepted within the system as well. You get the picture.

On the other hand, its counterpart, an analog system, uses continuous values for data presentation. Within this system, the data could be divided down infinitesimally. Not satisfied by the data value of 1.2, feeling that it is not accurate enough? Drill deeper and you may get 1.26. Deeper more and you may get 1.257. And so forth the value goes.

Resin Identification Code

If you were to flip over most everyday items made of polymer, especially those which are disposable, you would have noticed the triangular sign with a number within and maybe some alphabets below. This is the Resin Identification Code, and unless you were working with a disposable consumer item and your company is committed to label their product accordingly, you may not have given it  a second's thought.

Image taken from Flickr (by holeymoon)

In order to address the recyclers' rising need for a clear indication of polymer used, Society of Plastics Industry, Inc (SPI) developed and introduced the identification code in 1988. This code is usually found in packaging and containers since these are the main targets of municipal recycling programs, seeing that they are one of common items encountered within residential waste.

The code is used solely to identify the plastic resin in a manufactured item. In fact, the triangular label with 3 twisting arrows along with the number within are commonly misinterpreted. The number within is an arbitrarily chosen number to represent the target plastics, and has nothing to do with ease of recycling. A higher number does not mean that the plastics is harder to recycle.

Folding Plug

Ever thought of the fact that however portable and sleek your laptop or latest gadget is, the huge rectangular plug with its 3 bronze pins sticking out totally diminishes the definition of "sleek"? No matter how innovation is done on every part of an electronic device, the plug is the one with almost nonexistent change as far back as anyone could recall.

Folding Plug can, as its name suggests, be folded and carried with greater mobility (image taken from The Guardian).

IP Rating - Immersion vs Water Jet

Followers of this series of articles on IP rating will recall that a higher number on the 1st numeral will satisfy the requirements of a lower number (i.e. IP6X will mean that it passes all requirements from IP1X to IP6X, revisit here if the reader is interested). It would be prudent to note that such is not the case for the 2nd numeral.

An IPX4 test in progress. The semicircle apparatus sprays water through tiny nozzles lining the inner circumference. The apparatus is designed such that the water spray will reach the product from all directions. Notice that the spray is constrained to the top of the product, and the bottom is free from its direct effects (image taken from Qualilab).

The reason behind this is the difference in test requirement: 

• IPX1 to IPX6K, and IPX9K requires the product to be subjected to a flow of water impacting on the product 
• IPX7 and IPX8 requires the product to be immersed in a body of water.

In order to understand the test requirements, it is essential to first understand the application of the product in an environment prone to water ingress. Water ingress into the product could come in two different scenario - the product could be sprayed on by water jets, or it could be dropped into a body of water for a determinate period of time. It is possible to be subjected to both scenarios throughout the product's application lifetime as well.

IP Rating - Waterproof

Just as it would be difficult to judge the level of protection of "dustproof" products, the same applies to the term "waterproof" - it gives no indication the level of protection the product affords apart from the fact that it is protected against water ingress.

A waterproof iPod Stereo Case - how would you judge the term? Will the casing be free from water ingress if submerged for more than 1 hour? How will an engineer judge the term "waterproof" for critical engineering equipment? (image taken from Marine Audio and Stereo)

The 2nd code element of the IP rating helps shed some light on the level of protection, which is listed in the below table. The technical term usually associated to this code element is "protection against liquid ingress".

What Engineers could learn from the movie "Titanic"

A couple of days ago, I went to see Titanic 3D. This is my second, or maybe third time seeing the movie since 1997/1998 (it’s true, I swear! I know some of you saw it 10 times back then, don’t lie to me ;P). Back then when I was a teenage girl, Titanic did not left any impact on me from the engineering point of view, all I saw was the tormenting love story between star-crossed young lovers, Jack and Rose. Of course, I was like any other teenage girl back then, all doe-eyed for Leonardo DiCaprio.

Image from IMDb also includes reviews. 

Alright, this post is not actually about all the gushy-mushy gooey dooey loveyy storeyyy or how cute Leo is, but rather it is about the engineering lessons we could all learn from Titanic (3D or 2D, likewise).