An artificial disc device for replacing a damaged nucleus is disclosed. Corresponding decoding methods and apparatus are also disclosed. The low profile of a wheel chock allows each to be positioned under a vehicle the rocker panel of which has its lower edge only 148 mm above the surface upon which the vehicle’s tire rests, so that the installed chock height is reduced to 47. A protruding plate is formed on an inside periphery of the first aperture blade. If the pressure drop reaches a predefined limit, the valve is switched into an intermediate position, resulting in a smaller portion of the exhaust gas flowing through the heat exchanger duct than when the valve is in the first position and a remaining portion flowing through the bypass duct, thereby reducing the pressure drop across the heat exchanger system. The system comprises management device that puts management information together and sends and receives various information of countries for demand of the fresh water, analysis information of the fresh water, and various information of transportation device for transportation of the fresh water to the countries.