Thursday, December 26. 2019How a soldier can ‘see’ in the dark?
The nightsight can turn night into day for a soldier, which means that darkness no longer provides cover for enemy troops. With a nightsight their movements can easily be detected, exposing them to accurate fire. A nightsight looks like an oversized telescopic sight. It enables a soldier to see clearly on all but the darkest nights by amplifying moonlight or starlight. First a highly sensitive photoelectric cell converts the image into an electrical signal, just as it would in a TV camera. Then the electrical signal is amplified by circuits similar to those of a hi-fi amplifier. It is finally turned back into an image and displayed on a small TV screen. Even on a night that most people would describe as pitch black, there is usually some light, if only from the stars. In such conditions a soldier can accurately aim at a target up to 400yds (365m) away. More powerful versions, with a range of 1100yds (1km), are used by artillery, tanks, helicopters and aircraft. If there is not even a glimmer of starlight, a different instrument can be used – an infrared camera, which detects hear rather than light. Objects that generate heat – for example aircraft, missile outlets, or army camp fires – can be detected at a range of several miles. These signals are used routinely in surveillance operations. During the Falklands War, they were used by British troops to detect the position of Argentine defences. Infrared cameras can also detect the body heat of an enemy soldier. When all soldiers, tabks an aircraft are regularly equipped with nightsights, battle will be possible 24 hours a day.
Picture Credit : Google Wednesday, December 25. 2019What is the device called that record all flight data?
The most important pieces of wreckage to be recovered are usually the two recorders carried on all civil airliners. The flight data recorder provides a record of the movements of key instruments, such as airspeed and altitude indicators, and the positions of rudders and spoilers. The information is recorded as electronic pulses on a tape. When the tape is played back, it will give a computer printout of the aircraft’s movements. A computer screen can also be programmed to look like the main instruments, giving a more realistic playback. In the future it may be possible to increase the items recorded and to play them back through a flight simulator, which is normally used for training pilots, to re-create the cockpit of the aircraft in the hours before it crashed. Flight data recorders can record up to 200 hours of flying time. Cockpit voice recorders pick up conversations and sounds of the crew. They work on a continuous tape lasting 30 minutes, so at any time only the last 30 minutes is recorded. A weakness of the system is that if a crash does not stop the recorder working, it can remain switched on and erase the vital section. The recorders are installed in the rear of aircraft – the area most likely to survive a crash. They are housed in a case made of two shells of stainless steel with heat protective material between. They must be able to survivor a temperature of 2000ºF (1100ºC) for 30 minutes.
Picture Credit : Google Wednesday, December 25. 2019What are the old and new ways of outsmarting smugglers?
Customs officers at Southampton were highly suspicious of part of a cargo on its way from Colombia – a major drug-producing country – to the Netherlands. The padlocks on a container filled with ceramic tiles seemed to have been tampered with. So, with nothing more than this and intuition to go on, the officers decided to investigate. The cargo had been unloaded from a container ship for routine re-stowage and the officers had to act swiftly and secretively. They removed the container for examination and came across a hidden steel compartment 4in (100mm) deep running the length of its top. The compartment was cut open with oxyacetylene torches and inside was found 460lb (208kg) of cocaine, in 263 small packages, with a street value of some £51 million ($79 million). The container was sealed up again – with bags of grain substituted for the drugs – and put back on the ship without anyone being the wiser. The ship continued its voyage and the container was unloaded at the Dutch port of Rotterdam. Together with its load of tiles it was taken to a caravan site. There a gang of eight men began cutting into the roof. As they did so, Dutch police moved in and arrested the smugglers – who were later tried and imprisoned for up to six years for importing and dealing in cocaine. The incident took place in the autumn of 1987 and was typical of the way in which modern customs officers work. Despite the introduction of electronic surveillance techniques, the tried-and-true methods of experience and intuition –plus underworld tip-offs and international cooperation – have a large part to play. Dark glasses Any incoming foot or vehicle passenger who behaves nervously will attract the customs men’s attention. The officers are on the lookout for anyone who is unduly agitated – who blinks more than the usual 20-30 times a minute; who wears dark glasses to hide such telltale signs; who perspires unduly (particularly, with men, on the backs of the hands); or whose breathing is fast and noisy. Once their suspicious are aroused, customs officers may use special equipment to probe further. With a spectroscope – a long thin tube with a lens on the end – they can look into petrol tanks or behind door paneling. Optical fibres in the tube carry a picture back to a small eyepiece. The device is like a telescope that sees around corners. Special X-ray machines give a colour picture and are ‘tuned’ to detect anything concealed inside a container. For instance, they show the size and relative position of objects inside a bag, even if a large number of bags are stacked together. One of the most useful machines used by the officers is also one of the simplest: the weighing machine. Officers know what an average luggage bag weighs when full. So bags belonging to suspect people are weighed, and if they are found to be overweight they are searched. Or a bag might be emptied and then weighed. If it weighs more than the weight given by the manufacturers it could be searched for drugs, diamonds, gold or other contraband hidden in compartments in the lining. Sometimes, a bag is singled out after it leaves an aircraft by an X-ray machine or a sniffer dog. Customs men wait until the bag has been reclaimed by its owner – and they stop him as he passes the checkpoint. Customs officers pay close attention to passengers arriving from countries with a reputation for exporting drugs. In particular, they are on the lookout for ‘swallowers’ and ‘stuffers’. These are poorly paid couriers who put drugs, mainly cocaine or heroin – into condoms. They then either swallow the condoms – and retrieve them later by defecating or vomiting – or stuff them into bodily orifices. At ferry ports and frontier crossings, drivers or passengers who cannot give an adequate explanation for their trip, those that appear tense or hesitant, or a scruffy person driving an expensive car, might be subjected to a check. Many seizures are the result of chance suspicious; but many more are due to hours of painstaking detective work on the part of the customs officers. This involves surveillance, undercover work and informers – in many countries and often over long periods of time. The strange case of the drug-carrying snails In July 1988 a customs officer at Hanover airport in West Germany became suspicious of a passenger carrying a battered holdall who had just flown in from Lagos, the capital of Nigeria in West Africa. The holdall was opened and found to contain a plastic bag full of live edible snails – agate snails, or Archatina fulica, whose shells, the officer discovered beneath it several small packages, each containing just under 1oz (28g) of heroin. Similar packages were found hidden in the other snails, making a total of some 21oz (595g) of the drug. The smuggler was arrested – and the Hanover customs men reported the case of the 16 drug-carrying snails to their colleagues throughout Germany. From then on a keen eye was kept on passengers from Nigeria. Two weeks later another Nigerian was caught at Hanover airport trying to smuggle in a slightly larger cache of heroin also under the shells of agate snails. Thanks to an officer’s alertness, an ingenious new means of smuggling had been thwarted.
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