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2012年7月9日 星期一

Cu Chi Tunnels - A Lesson in the History of the Vietnam War


The Cu Chi Tunnels near Ho Chi Minh City are an incredible destination for war and history buffs. During the Vietnam War it was the major battleground between the U.S and Viet Cong.

In the heart of the jungle, 200km of tunnels were well hidden from American soldiers.  Originally built to protect the Vietnamese from French air strikes in the lat 1940's to 1950's, they were re-used during the 60's as a staging ground for attacks on American troops.

Surprisingly, the U.S. knew that the tunnels were there, they simply could not find them or destroy them.  They put everything they had into taking out the tunnels from dispersing agent orange and napalm to relentlessly dropping bombs, but the caves remained in tact.  The land didn't fare as well and the jungle was completely destroyed along with everything in it. Today it is thriving once again however, showing that with time, the earth can repair even the harshest results of destruction.

If you are lucky, you may receive a first hand account from a former Vietnamese soldier.  Guides will tell you stories of their time in the war and can give you information on intimate details of the war that took place in this jungle.  If you listen carefully, you can learn a great deal about history.

The Viet Cong used the jungle to their advantage.  They could run through with ease, knowing their way around their own land and had several cave entrances at the ready to disappear into.  They were hidden well with termite hills placed atop, or with leaves scattered above.  Guide dogs could not follow their scent because they would sprinkle cayenne pepper around the entrance confusing the dogs and making them turn in the opposite direction.  They could safely disappear into the 200 km system and if followed, the American soldiers couldn't fit inside anyway. The entrances were tiny and made for a slight frame, for a large U.S. soldier, fitting in would be almost impossible without blasting it.

They knew their tunnels well, unlike the American soldier. They would enter the tunnel avoiding the booby traps placed to kill or maim the enemy.  Several different types of crude traps were laid in wait for the poor soldier that had to follow them in or the soldier that was sent to investigate upon a discovery.

There were other tactics besides the tunnels that offered the Vietnamese an advantage against the United States. Surprisingly, foot rot was a major problem with U.S. soldiers. The heat and humidity of the rain forest caused sores, rotting flesh and infection. When your major form of battle is to walk through the jungle this can be a serious problem. Instead of wearing boots, the Vietcong wore rubber sandals made from tires. They are well constructed and durable and you can see them for yourself. If you want to try them out, buy a pair for a nominal fee.

It is impossible to imagine how people managed to live in these tunnels for several years. The passageways were very tight at less than a meter high and they were dark and filled with disease. They had to deal with insects and venomous snakes and the fear of being found out. However, the Vietnamese managed to carve out a way of life however building kitchens, living areas and first aid stations.

Your tour will take you to all of the different types of living quarters and rooms. It is a comfortable tour and the tunnel walls have even been blasted out to make it larger and more comfortable for tourists.  However, there are still some original entrances available to be explored and you will have the opportunity to go into an original tunnel yourself and crawl for 150 meters experiencing what it was like during the war.

Your guide will take you to an original entrance which is simply a very small hole in the ground.  He will show you how to enter and then you are on your own to squeeze through and make your way to the other end.  It can be frightening indeed, but be sure to give it a try. It is a crazy experience to crawl through these tiny tunnels and imagine what it must have been like for its inhabitants.

After you have thoroughly explored the caves, you will also learn other ways that the Vietnamese managed to defeat America. They could track soldiers easily in the jungle by using plants. You will see how they cooked only during the foggy mornings to hide their smoke and you will learn how farmers smuggled food to the Vietcong. It is a very informative day.

Now that you have learned all that there is to know about the Cu Chi Tunnels, you will be given the opportunity to feel what it was like. Believe it or not, you are given the chance to fire and AK 47. Or can choose your automatic weapon of choice and for the cost of $1 a round you can feel the power of these destructive weapons by firing them at the shooting range completing your Vietnam war tour.

Visiting the Cu Chi Tunnels will definitely give you a feeling as to what life was like during the Vietnam War.  It is unbelievable to think that these tunnels remained in tact through two major wars. One with the French and one with the Americans. If you are visiting Ho Chi Minh, they are certainly worth a visit.




Debra Corbeil is one half of Canada's Adventure Couple with her husband Dave Bouskill. Together they have traveled to over 30 countries on 5 continents. Follow their journeys at http://www.theplanetd.com as they hike, bike, dive, trek and climb their way around the globe. You can also see their photo stories at http://www.picturetheplanet.com.





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2012年5月4日 星期五

The Dead Sea History!


The Dead Sea

Dead Sea, located in the south of the Jordan Valley, the salty closed sea 400 meters below sea level is the lowest spot on Earth. The scenery on the shores of the sea in enchanting.

The Dead Sea is famous for its extraordinary salt and mineral content, which many people say makes it a natural healing agent for skin problems. To ORDER The Dead Sea Products Click HERE. Or visit http://www.giftsfromtheholyland.com. Or call TOLL FREE 1-888-336-3275. People from around the world have been visiting the Dead Sea for many years for curative treatments and to enjoy its relaxing waters.

5.000 Years of History

King David, King Herod, Jesus, and John Baptist were closely linked with the Dead Sea and its surroundings. The prophets knew it via the infamous Sodom and Gomorra. During the Egyptian conquest it is said that Queen Cleopatra obtained exclusive rights to build cosmetic and pharmaceutical factories in the area. Later on, the wily Nabateans discovered the value of bitumen extracted from the Dead Sea and needed by the Egyptians for embalming their mummies. Aristotle wrote about the remarkable waters. In Roman times the Essenes settled in Qumran on the Dead Sea northern shore as a place of refuge and on the heights of Masada a small group of rebellious Jewish zealots held out against the might of the Roman Legion. The remoteness of the region attracted Greek Orthodox monks since the Byzantine era. Their monasteries such as Saint George in Wadi Kelt and Mar Saba in the Judean Desert are places of pilgrimage. Bedouin tribes have continuously lived in the area and more recently explorers and scientists arrived to analyze the minerals and conduct research into the unique climate. Since the 1960's, tourists from all the world have also explored the Dead Sea region.

The Lowest Point on Earth

Situated on the heart of the Great Syrian-African rift valley that stretches throughout Israel and beyond, the Dead Sea is the lowest point on the earth (400 meters or 1,320 feet below sea level), and is flanked by the Judean Mountains on the west, the Hashemite Kingdom of Jordan and the Mountains of Moab on the east, the Jordan Valley and Sea of Galilee to the north and the Negev Desert as well as the Red Sea to the south.

The Dead Sea Water

The water of the Dead Sea contains 21 minerals including magnesium, calcium, bromine and potassium. 12 of these are found in no other area or ocean and some are recognized for imparting a relaxed feeling, nourishing the skin, activating the circulatory systems and for easing rheumatic discomfort and metabolic disorders. As an example, the Dead Sea contains 10 times more salts and minerals than the Mediterranean Sea. The high salt and mineral concentration enables everyone to float in its waters but doesn't allow the proliferation of fish and other marine life.

Thermo-mineral Springs

Found in several locations along the Dead Sea shores. The many minerals contained in the warm water are dominated by sulfur. Soaking in the heated sulfur pools activates the circulatory system and increases the oxygen supply to the body.

Natural mineral spring water

Flows from the Judean Hills into the lower areas fronting the Dead Sea. When hiking along the area's "wadis" (seasonal dry river beds) and oasis, one can often splash in waterfalls and cool streams. Natural mineral spring water is bottled and locally marketed throughout the country.

The Sun

The Dead Sea is the only place on earth where one can sunbathe for extended periods with little or no sunburn because harmful ultraviolet rays are filtered through three natural layers: an extra atmospheric layer, an evaporation layer that exists above the Dead Sea and a rather thick ozone layer.

The Air

The region's miraculous air is dry, unpolluted and pollen-free with low humidity. Due to the constant evaporation, the air contains high concentrations of several minerals, mainly bromine, providing a genuinely relaxing effect.

Because of the high barometric pressure it has approximately 8% more oxygen than anywhere else on earth and consequently makes breathing easier.

Black Mud

A signature element of the Dead Sea, black mud is homogeneous mixture of Dead Sea minerals, important organic elements from the shoreline as well as earth. Indulging in a black mud body wrap has both cosmetic and therapeutic benefits - known to cleanse and stimulate the skin, relieve muscle and emotional tensions, improve blood circulation, and ease rheumatic pain. The rich minerals and the mud tightening action promote circulation by increasing the supply of oxygen to and removing the toxins from the skin, thus toning and firming up skin tissues, leaves the skin glowing and youthful looking. Dead Sea Mineral Mud cleans, purifies, and restores the skin's natural minerals.

The Salt

As the name suggests, the Dead Sea is devoid of life due to an extremely high content of salts and minerals. It is these natural elements which gave the water its curative powers. Dead Sea Salt and Dead Sea Mud have been recognized by millions of people as a single source of health and beauty since the days of Herod the Great, more than 2,000 years ago. The Dead Sea has a 33% concentration of salts and minerals (compared to only 3% in the ocean). Dead Sea Salt original mineral composition improves cell metabolism and contributes to its restoration and regeneration. Dead Sea Salt also acts as a disinfectant and help in removing harmful substances from the skin.




Anwar Abedrabbo CEO Gifts FromThe Holy Land john@giftsfromholyland.com 1-888-336-3275 Voice/Fax





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2012年3月10日 星期六

History of the Computer - Cooling, Part 2 of 2


Computer manufacturers specified the heat load required to be handled, the required flow of conditioned air, and the temperature to be measured at the cabinet entry points. Most systems were installed on false floors, with a space of about 1 meter or 3ft below the floor. This allowed the air conditioning to be supplied under the floor, and exhausted through the false ceiling. This space was also used for cabling the systems. An air lock was often provided for entry and exit.

Other components of the computer system, such as disks, also generated heat and had to be considered. Tape drives were particularly large producers of heat. It was common, on large scale systems, for the tapes and disks to be installed in a separate room, or partitioned off from the mainframe, so that air conditioning requirements could be better controlled. (Printers were also partitioned, but mainly for noise, dust, and publishing requirements.

For instance disks are sensitive to rapid changes in humidity, as condensation forming on the disk surface can cause head crashes, due to the small height the head flies at. Tapes produce a lot of heat due to the powerful motors they use, but are more tolerant of temperature changes.

Integrated circuits, or chips, introduced at the end of the 1960s, produced a similar escalation in heat generation and tolerance. As they became more sophisticated, and LSI (large scale integration) was common the escalation continued. This problem is still with us today - have you tried using a laptop on your lap lately? Apart from ever more sophisticated fan design, coupled with heat sinks and air flow funnels or plenums, another approach has been used from time to time. This is the system we mentioned above, water cooling.

The computer user already provides a close tolerance power supply, sometimes at different frequencies, such as 400Hz instead of 50 or 60. He must also supply air conditioning with temperature and humidity gradients specified within tight limits. Now he is required to supply chilled water, also to tight tolerances.

The computer logic circuits were assembled on multilayer PCBs (or PCAs - Printed Circuit Boards or Arrays) which were 'plugged in' to the backplane. The Backplane was a large multilayer printed circuit panel, of varying size, depending on the system, but normally around one metre or 3ft square. Approximately 60-100 PCBs would be plugged in to this panel via a multipin connector, with several hundred pins, on the board.

The multilayer PCB or backplane had been necessary since the early 1970s, due to the incorporation of many more circuits on the board. A single two-dimensional plane could not hold all the interconnections required for this multitude of circuits. The multilayer board incorporates circuits on each layer, with links through the layers, to accomplish the required connections.

For water cooling, the PCB consisted of a large heat sink, around which the circuit components were assembled, through which the chilled water flowed. When the PCB was plugged into the backplane, it also connected via special leak proof connectors to the chilled water supply flowing in the backplane. In turn, the backplane was connected with larger leak proof connectors to the customer supply.

Today's systems are usually physically smaller for the same computing power, and are designed to have a larger tolerance of air conditioning requirements, some in a so-called 'office environment'. They are designed with a wind tunnel approach, and require all doors to be closed.




Tony is a retired computer engineer, with 40 years experience, building on his previous electronics engineering on radar and automatic controls. He is now working from home on the internet. This article, brought up to date, with diagrams and illustrations, forms part of his latest book. For further information and details, please visit the website Computer Fundamentals





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