|SCIENCE TRIBUNE||Thursday, August 8, 2002, Chandigarh, India|
And now some handy tools
Types of compact disks
Worse than cholesterol
Mice, men and genome maps
And now some handy tools
Howsoever precise, versatile and easy-to-operate the instruments may be, the most liked ones by the scientists and engineers are those that fit into the palm. Like a cell-phone, these act as enabling accessories that can be packed in a briefcase while going on an inspection tour or carried in hand during the site-visits. Science Tribune has earlier highlighted many electronic and computerised instruments used for non-destructive testing of structures and for precise and accurate surveying work. Here is another treasure of information regarding such instruments that are very handy, extremely useful and fuss-free for the user.
Moisture Meters : Moisture meters are handy instruments that can check the moisture carried by building materials such as concrete, marble, soil, tiles or wall papers in themselves. These are very light in weight, weighing not more than 150 to 300 grams and comfortably fit into the palm. These are battery operated, have an LCD display and carry two button modes: search mode and measure mode. Search mode is used to identify the presence of water on a surface or even behind a decorative finish such as wall papers or tiles without causing any damage to the finish. It uses a radio frequency to identify the presence of moisture in a material.
A relative scale tells whether the material under probe is dry or damp. This instrument can measure moisture even up to a depth of 20mm.
The measure mode is used to tell the percentage of moisture in the building material. Some of the moisture meters carry even a colour code displaying green colour for dry, yellow for border line and red for damp materials. Moisture meters are extremely useful instruments as moisture content of many surfaces and materials has to be kept within permissible limits before these are worked upon.
Hygrometers : Hygrometers are instruments to tell the relative humidity and ambient temperature of the environment. These carry a condenser mode also, which if operated, tells the amount of condensation on surfaces by displaying the difference between the dew point temperature and the temperature of the surface. Just a sensor is held against the surface and the readings are displayed on the hygrometer. These instruments are specifically useful for scientists, civil engineers and environmental engineers.
Timber Masters : These handy instruments are excellent for quality control application in wood work in buildings and furniture. These show the moisture content of wood along-with its temperature so that a relation between the two parameters could be established. Timber masters carry very fine pin electrodes which are inserted into the wood and the readings are displayed on the screen. The weight of a timber master including that of batteries is just 150 grams, its length not more than 6 inches and thickness less than 2 inches. These instruments are a must for every engineer supervising wood work and help in avoiding warping of wood at a later stage as decision to use the timber or not can be taken with respect to its moisture contents.
Timber masters are provided with an optional hammer electrode also. This electrode can penetrate even the hardest woods up to a depth of 37 mm.
Dial Thickness Gauges : Engineers have been using disc type measurement gauges to check the thickness of GI sheets, MS sheets, PVC sheets and other fine materials. These gauges have been very rough and chances of a large error are not ruled out in their use as the thickness of sheets under measurement may be just a fraction of a millimeters. An experienced engineer may rely more on his visual judgement than on a disc type gauge in differentiating between a 22 gauge and a 24 gauge GI sheet.
To have a cent percent accurate measurement, dial thickness gauges produced by Mitutoyo, Japan, are best instruments, measuring from 0.01mm to 10 mm thickness of a sheet. These hand-held dial gauges are easy to read and shock proof also.
Elcometers : Elcometers are handy instruments to check the thickness of surface coatings on metallic and other surfaces. To avoid corrosion, metals need a certain minimum thickness of paint coatings over them. It has not been possible for an engineer or user to measure the thickness of the paint applied by the contractor or manufacturer over the metallic surfaces.
There is always a tendency to save paint by applying thinned material and an engineer can do nothing unless he proves that the paint thickness is not as per specifications. On the other hand, application of too thick coatings may cause wastage of material and it may come off in flakes at a later stage. Elcometers prove very useful here. These can measure the thickness of coatings even up to 0.002mm. These look like calculators, have a LCD display, weigh from 150- 300 grams only and have a small size of 2.5x5.0x1.25 inches only. These carry an attached lead whose transducer when pressed upon the coated surface gives the reading.
Use of elcometer is extremely simple. However it has hardly been used in India, perhaps due to lack of knowledge of its existence. An elcometer can operate at -20 to 500 C temperature range. It can be applied to steel, cast iron, plastic, epoxy resin and even glass fibre. It can store up to 1000 readings in its memory.
Some elcometers carry an alarm facility also. The required thickness is pre-fed into these elcometers. As these are moved over the surface to be checked, an alarm goes off as and when the thickness of paint or coating is lesser than that required. About 60 readings can be recorded in a minute.
Glossmeters : Some standards and specifications demand a physical assessment of the gloss provided to metallic surfaces in vehicles, furniture, equipment and domestic items. In addition, the gloss provided on floorings, ceramics, plastics, mirrors and printed posters also needs to be measured. Correct gloss provision is a symbol of uniformity, compatibility and protection from surface-deterioration. Glossmeters help in accurate measurement of gloss finish.
Glossmeters measure the gloss in gloss units ranging from 0 to 1000 units. While the zero reading refers to a non-reflective surface, 1000 units refer to a mirror-finish. To measure the Gloss, a constant power light beam is directed at an angle towards the surface to be tested. Different reflective angles varying from 20 degrees to 85 degrees are fixed for different surfaces. The Glossmeters weigh from 900 grams to 1200 grams and have a size of 7x2x4.5 inches. These can record measurements to an accuracy of 0.5 gloss units.
Roughness gauges : In most cases, the roughness of a metallic surface is assessed by touch or sight. Sometimes it needs to be assessed accurately to determine the type of application of paint over the surface. For this purpose, Roughness gauges come quite handy. These gauges are magnetic in nature and do not need a battery to operate them. Each gauge carries 0-10 divisions and a colour band. When the needle is within Blue band, it indicates that the surface is suitable for painting. Yellow band indicates that the surface is suitable for sprayed coatings. A Red band reading means that the surface needs hard sprayed deposits. These gauges too are light in weight, weighing less than 200 grams and have a size of 3.5x2x1 inch only.
Whenever a paint coating or a finish is applied to a surface, the
presence of moisture in the environment or invisibly present on the
surface to be worked upon causes a poor quality finish. That is why it
is not desirable to paint surfaces during winter. This moisture may
also result in poor adhesion of the coating to the surface causing its
coming off. To know the presence of moisture, dewmeters prove to be
quite helpful. While the hygrometers explained above tell the Relative
Humidity, Dewmeters tell the dew point and give off an alarm if it is
unsafe to paint the surface.
Types of compact disks
A compact disk consists of an optical medium for storing digital data. Compact Disk (CD) is incorporated as 125 mm diameter disk of polycarbonate. The diameter of the hole is of the order of about 12 mm. The data storage area starts from 45 mm diametre and is terminated at about 120 mm. The data is written on the CD in the form of helical pits and the edges of the pits refer to binary 1. The distance between successive tracks is about 1.5 micron. The data can be stored onto the CD in either compressed or uncompressed form and they are available in recorded or re-writable mode.
The audio CD consists of the recording process in uncompressed mode. Here the audio signal is transformed into digital data at the sampling rate of 44.1 KHz with 16 bits per sample. At the CD player side, this uncompressed stored data is converted back to audio signal. Data sheets reveal that about 70 minutes of uncompressed music data can be stored onto and audio CD.
Uncompressed audio data needs a large amount of disk storage space. Motion Pictures Expert Group (MPEG) layer-3 is the available software file format for compressing audio files. MPEG is a video compression standard developed by ISO by the Motion Picture Experts Group. This subsequently results in a lesser requirement for disk storage space. CD music can be sent on the Internet by using MP3 format. MP3 exploits the characteristic of human ear to accept the reduction by a factor of 12 without affecting the quality.
The video CD is a blend of both the audio tracks and the video part. MPEG-1 is used to compress the video and record the data. The Level-2 format of Video CD enables about 75 minutes digital video and audio storage on the CD. A dedicated control stream is a part of the data stream, which helps in the playback process. The Digital Video Disk (DVD) offers an improvement over the CD in terms of storage capacity and efficiency. More tracks are packed onto the same disk as compared to the CD. The tract compression coupled with the usage of dual layered tracks improves the throughput considerably. The audio and video quality shows a marked improvement. The emergence of DVD ROM on the storage platform will pave the way for a revolution in computer and entertainment world.
NEW PRODUCTS & DISCOVERIES
Two researchers in Dublin’s Media Lab Europe have designed a tooth that could be used to wirelessly receive digital signals from a mobile phone.
James Auger and Jimmy Loizeau, who are now researchers at Media Lab Europe, came up with the idea as part of a future product competition run by the UK’s National Endowment for Science, Technology and the Arts while at the Royal College of Art. The project will be on show at the UK’s Science Museum for the next six months.
Essentially the futuristic tooth would use wireless technology, such as 802.11 or bluetooth, to take signals from audio devices such as mobile phones, radios, stereos or computers, Auger explained to ElectricNews.Net. These signals would be changed into vibrations that would travel from the tooth, to the skull, eventually creating audible sound in the user’s inner ear. No one but the user would be able to hear the sounds.
The two men have not yet built a prototype, and Auger is hesitant to say whether the men would be interested in turning the project into a commercial venture, only saying, "We will just wait and see."
"That was never really our intention," Auger explained. "What we were really interested in was the feedback that the idea generated." He went on to say that part of the project was simply to see how people reacted to futuristic biotechnology that was easily foreseeable, but did not yet exist. "Mostly people were shocked at the idea," Auger claimed.
"Lots of people put it into a medical context...it seems to be quite acceptable to allow technology into the body for replacement purposes such as artificial joints. Lots of people, when they see it, see it as an application that could be used for deaf people, which is not an idea we put out there," Auger commented.
At Media Lab Europe Auger plans to continue to generate ideas about new technologies to gauge what people think about the notion of replacing or enhancing body parts with machines or other technological means. Currently he is working on a project that deals with the social implications of genetic modifications.
Worse than cholesterol
Worse than cholesterol? Hard to believe, perhaps, but the top health concern of millions of Americans is about to be trumped by what doctors say is an even bigger trigger of heart attacks.
The condition is low-grade inflammation, which may originate in a variety of unlikely places throughout the body, including even excess fat. New federal recommendations are being written that will urge doctors to test millions of middle-aged Americans for it.
The discovery of its surprising ill effects is causing a top-to-bottom rethinking of the origins and prevention of heart trouble. Doctors call it a revolutionary departure from viewing the world’s top killer as largely a plumbing problem blamed on cholesterol-clogged arteries, the standard theory through the modern era of cardiology.
"The implications of this are enormous," says Dr. Paul Ridker of Boston’s Brigham and Women’s Hospital. "It means we have an entire other way of treating, targeting and preventing heart disease that was essentially missed because of our focus solely on cholesterol."
In the past year or two, experts say, the evidence has become overwhelming that inflammation hidden deep in the body is a common trigger of heart attacks, even when clogging in the arteries is minimal. Now the main question is: How aggressively should otherwise healthy people be tested to find and treat it?
The new recommendations are still being drawn up, but they will offer the first formal blueprint to answer this, probably some time in the fall. Doctors writing them say they will almost certainly recommend broad testing. AP
Mice, men and genome maps
Scientists have mapped 98 per cent of the genome of the mouse in a breakthrough that is expected to speed up the hunt for human genes and improve understanding of how they contribute to diseases.
A consortium of scientists from Britain, Canada and the United States collaborated on the genetic map — regarded as the most important since the human genome was sequenced — which was published last week on Nature Online, the website of the science journal Nature.
"It will help identify the common genes
between the mouse and humans,’’ Simon Gregory, leader of the project at the
Wellcome Trust Sanger Institute, said in an interview. Reuters
SCIENCE & TECHNOLOGY CROSSWORD
Solution to last week’s