Thglimited - Heavy Industries

we did something interesting at tafe this morning! we stretched steel and aluminium till it broke, crushed concrete and bent wood. well, we watched these things happen while recording numbers; still it was a highlight. then in the afternoon it was back to the usual, reading and avoiding eye contact with the teacher, trying not to get too frustrated, trying to let go of the hope of learning anything in class, and to not get anxious and mourn, or calculate, the time that i spend there, every day, or the time i'll need to spend to actually cover the work, later.

at least i'm getting through some reading, sometimes writing some workshops. i've already calculated the number of bricks visible in that room: there are a total of 4453 bricks, comprising 3630 pale whole bricks, 564 pale half bricks, 227 dark whole bricks and 32 dark half bricks. i'm not sure where the odd number of whole dark brics comes in, maybe there was an error, but no doubt i'll figure it out sometime before the end of the year.

things are happening, but i'm too tired to make my brain work. four days a week of tafe hampers my ability to construct sentences.

i think i've found the solution to how to fit my twenty hour a week tafe course into my life. completely ignore the teachers when they're mumbling and difficult to understand, and write those workshops i've been procrastinating on! i'll have to do all the work at home before the exams anyway, so why pretend it's worth doing twice?

in my first semester back at tafe, doing mechanical engineering, i have been required to complete exactly one assignment. true to form, it was late. but that was ok. now that i've lost all my files i'm realising that there actually is a value to the work i've done, the research and compilation i've sweated over for countless semesters. value akin to that of a blog, in fact. so here is the assignment, in the blog. read it if you're interested... but them's the rules round here!

A solar hot water heater uses energy from the sun to heat water, thereby saving on non-renewable energy, greenhouse gas emissions and cost. There are many ways to build a solar hot water heater. The focus of this paper is on a domestic system that a non-specialist could adapt form their existing home hot water.

The main elements of a solar hot water heater are the collector and the tank, which are connected by insulated pipes. Other components, such as valves, pumps and booster heaters are optional, depending on choices and circumstances.

The solar collector (also called the absorber) is what differentiates solar systems from other hot water heaters. It consists of a metal sheet with channels, which in an open system either house water pipes or conduct water themselves. In a closed system, the channels or pipes conduct another liquid, generally with a lower freezing point, and the heat is transferred to the water protected below. The simplest method employs pipes, generally made of copper, and set into a sheet of aluminium, or copper to avoid the corrosion which occurs when different metals are in contact with each other.

To maximise the absorbed energy, all the metal is painted black, or ‘solar chrome’, a silvery selective surface, which is even better, as it absorbs more energy than it emits. This is all set in insulation to avoid wasting energy by heating the tray and roof. The transparent cover is usually a high impact glass. Low-iron ‘solar’ glass is even better, as it transmits near infrared energy better than less pure glasses.

The edges of the tray and cover must be well sealed to avoid water and other damage, with holes on the underside to release condensation, and strong brackets to attach it to the beams of the roof, beneath the tiles. The whole construction must also be able to withstand impact, abrasion, ultraviolet radiation and temperatures of at least a hundred degrees centigrade.

The collector needs to be approximately one square metre for every seventy-five litre of tank volume, So for a normal three hundred litre tank you should have four square metres of collector, more if there is shading, the glass is not kept clean, or it is not mounted at a suitable angle. It must face between 45 degrees either side of true North in the southern hemisphere, and be mounted at a specific angle related to the latitude of the location. In Sydney, at latitude 34 degrees, an angle of 34-39 degrees is the most efficient averaged over the entire year. However, increasing the angle to 44-49 degrees maximises efficiency in winter and reduces the problem of overheating in summer.

There are three main kinds of tanks. The most common commercially available solar hot water heater has a close-coupled tank, which is attached horizontally at the top of the collector, on the roof. This avoids the need for pumps with the thermosiphon effect, where the cold water is drawn down from the bottom of the storage tank, to be heated in the collector, after which it rises naturally back into the top of the tank. Installation, however, is be much more difficult than in models with separate tanks. A 300L tank exceeds 500kg, which would require a crane to lift it, and often reinforcement of the roof as well.

There are several advantages of using the house’s existing mains pressure tank, if one is available. It can be left at ground level, which makes installation, maintenance and replacement much easier, and it is already equipped with a mains pressure pump. Also, it will be an upright tank, which has better stratification than a close-coupled model, by allowing more distance between the heated and unheated water, which sit in layers in the same tank. Disadvantages include the increased distance of pipe and insulation required to connect the storage tank to the collectors, and a small cost in the running of the pump.

A third option is the low-pressure tank. This is the only type that is safe for a non-professional to create or adapt significantly. Low-pressure tanks can be made of a simple sheet of copper, but will also benefit from insulation. They are mounted in the ceiling to take advantage of the pressure of a head of water. If it can sit higher than the collector it can also use the thermosiphon effect. This system could still require roof reinforcement, and the lack of mains pressure is often undesirable.

All pressure tanks require temperature, pressure and vacuum relief valves. Low pressure systems can get away with vents. Temperature control, or tempering valves are also good at outlets such as basins and showers, but can be bypassed for washing machines and dishwashers, where scalding isn’t a risk. These can prevent boosters from kicking in, or mix in cold water when the temperature in the tank rises past set levels. Non-return valves are required on thermosiphon systems to prevent the water flowing backwards at night, and frost protection will also be required in frost prone areas.

Another component that is useful where winter sun isn’t always adequate is a booster heater. If a commercial mains pressure tank is used, a gas or electric heater will probably be already installed inside. This can be set to come on at night, only if a minimum temperature level has not been reached.

If attention is paid to all aspects, it is possible in summer to supply a house its total hot water requirement without reliance on non-solar energy. This can reduce the average power bill by a third. In a Sydney winter boosting will be required, but energy consumption will be drastically reduced.

References:

Fact Sheet 4.3 Solar Hot Water, from the Home Technical Manual: Design for Lifestyle and the Future http://www.greenhouse.gov.au/yourhome/technical/fs43.htm

Introduction to Renewable Energy Technologies Resource Book, January 2003 Edition. Published by the Renewable Energy Centre, Brisbane and North Point Institute of TAFE

Australian Standards AS 3500.4.2:1997 and AS 2712: 1993

It seems Dr. James Holsinger Jr. who bush is about to nominate as next Surgeon-General of the US, wrote a very homophobic article for the Committee to Study Homosexuality of the United Methodist Church. in it, he used a metaphor "In fact, the logical complementarity of the human sexes has been so recognized in our culture that it has entered our vocabulary in the form of naming various pipe fittings either the male fitting or the female fitting depending upon which one interlocks within the other." Hugh Robertson tells us this, in a blog snippet i came across, and argues well the importance of holsinger keeping his views out of his public office. of the quote, however, he says 'Now I do not propose to argue hardware terminology...'

now i do propose to argue hardware terminology. wow, in a blog i can expect you to hear me out, before you tell me that i'm being a bit silly and trivial.

as a student of mechanical engineering, i am under a constant bombardment of gendered context. i spend my days in a class full of teenage boys, listening to male teachers make 'harmless' jokes at their wives' expense, then having them accost me in the break to tell me how much they love and respect their wives, because they saw me roll my eyes. the kid who wears the 'lesbos, where every man wants to be' tshirt every week, didn't really understand why i was amused the first week, and really wouldn't understand why i get irritated now. the graffiti on the tables is of penises. i pull people up on their use of 'gay' as a term of abuse, but the gendered insults are too thick and fast and besides, i'm getting to know these people, and want to get along with them. i'm in conflict as to whether it's better when we are addressed as 'ladies and gentlemen' or just 'gentlemen', as these are often the choices. am i being included or singled out? the only female staff member teaches computers and communications, a subject from which i am exempt, and which is generally considered light weight. when i get top marks in something, my gender is commented on. sometimes the teacher is expressing pleasure at having a girl in the class. that kind of sex distinction can occasionally feel like a mitigating factor, until it turns out i'm expected to do better because i must be more careful. sometimes the expression is of suprise, which simply makes me feel dirty. i'd hate to think what would happen if i did badly at much.

and fittings which are useless without their counterparts, and categorically don't fit with their equals, are named 'male' and 'female'. just because it is entrenched doesn't mean it is benign.

Always wanted one of these ultrasonic cleaners, Maplin have had them in their catalogue for some time as well as CPC. Just bought one today in Tchibo (Richmond , Surrey) for a little under £14. I think they've a bit of sale. Cleaned my watch bracelet and a spectacle or two. Came out gleaming , well a fair bit cleaner, great! I guess it might be useful for other bits around the home, like the odd CD, clock or watch parts...

I've recently completed a large (for us) project with my son, namely a Meccanograph that draws pictures akin to the Spirograph toy of the 1960's.  Thanks to Mike Fallows for the plans and support in building same. Kew steam museum have a Meccano show every two years, the inspiration behind building such a machine.

title: Finite element analysis of vertebral end-plate failure under high dynamic axial load and its relation to age authors: Kalyanrao, Thorbole, Chandrashekhar
abstract: This research was aimed to develop the analytical model of functional spinal unit with the intent of understanding the contribution of Intervertebral disc condition on the failure mechanism of End-plates under high rate dynamic loading, The condition of the disc for young people is healthy as compared to old person. The simple single degree of freedom DRI (Dynamic response Index) model was utilized to measure the spinal deflection under the influence of dynamic loading is incapable of estimating the potential injury due to disc swelling. The failure considered is always the vertebral body failure due to crushing, but in reality, condition of disc plays important role in deciding the failure of the vertebrae. The detailed axis-symmetry model was utilized to understand the effect of various factors on the end-plate failure mechanism and it is observed that deflection of the end plate is critical failure criteria. The age and the peak load were found to be the significant factors dictating end-plate failure. In young people the deflection of end plate was higher as compared to the old people due to hydrated disc capable of swelling under dynamic loads. The simplified three dimensional model of vertebral motion segment L2-L3 was developed in order to understand the effect of nucleus pulpous pressure in end-plate deflection and to incorporate this model into the DRI model in order to estimate the effect of dynamic loading on the resulting spinal injury. The three dimensional model utilizes the MADYMO material models. The relaxation modulus for the nucleus and the annulus are obtained from the published results and the material parameters were mapped from these published data. Results of a sensitivity analysis indicated the major contribution of age on the end-plate failure. The result clearly indicated the need of modifying the present way of modeling the nucleus as incompressible fluid to viscoelastic incompressible fluid. This study indicated that failure of the end-plate was an important link in the failure mechanism of the spinal unit; this failure lead to the transmission of the disc tissue into the vertebrae and caused the burst fracture.
description: Thesis (Ph.D.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.

Have you been to the gas station this week? Considering that we live in a very mobile society, it's probably safe to assume that you have. While pumping gas, you've undoubtedly noticed how much the price of gas has soared in recent years. Gasoline which has been the main source of fuel for the history of cars, is becoming more and more expensive and impractical (especially from an environmental standpoint). These factors are leading car manufacturers to develop cars fueled by alternative energies. Two hybrid cars took to the road in 2000, and in three or four years fuel-cell-powered cars will roll onto the world's highways. ......................................

 

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Encouraged by a visit to a high end watch shop in Brighton at the weekend, I thought I touch on another passion of mine , namely mechanical watches. This comes about from a love of fine mechanical items, be they musical boxes, watches , clocks etc. Aspirations to owning an IWC or Patek Phillipe are sadly limited by my funds today. Having said that I do own a Zenith Elite Dual Time watch. Bought second hand I might add, albeit with original documentation and in mint condition. Zenith did a great job servicing same when they were based in Twickenham, Surrey. At one point Zenith supplied Rolex with it's movements. I'm told by some that Zenith are one of the remaining in house movement manufacturers, but in truth I get conflicting stories. i.e. many of the high end brands buy movements in, especially on their lower cost products.

Check out http://home.watchprosite.com/ for high quality articles on the watch industry.

Zenith Elite below: