Rotary Engine Essay Example

Rotary Engine Essay Example Rotary Engine Essay Rotary Engine Essay Svetlozar Simeonov 09/25/11 Wankel Rotary Engine – Huge Power in a Small Box According to Philip’s Encyclopedia Wankel rotary engine or just Wankel engine is â€Å"Internal combustion engine with rotors instead of pistons. † That not so popular engine is actually about two times lighter than a four cylinder piston engine, the one that we all have in our cars, for the same power output. It also has four times less moving parts. Much simpler, much lighter, much smaller it has numerous advantages over a conventional piston engine. One of the most simple and clear explanation of how the Wankel engine works oppose to piston engine comes from Time magazine: â€Å"Instead of converting up-and-down piston motion into wheel-driving circular energy through a series of complex linkages- the way a standard engine works- the Wankel rotors spin continuously and thus provide the proper torque to move a cars wheels directly. † (Time Aug 14 1972). It has four times less moving parts versus four cylinder engine. Therefore, Wankel engines â€Å"are smaller, peppier and potentially cheaper to build than conventional reciprocating models, and have only six major points of wear, v. 00 in a conventional engine† (Time Aug 14 1972). The Wankel engine was reviled in 1956 by its engineer Felix Wankel (The Columbia Encyclopedia – internal-combustion engine). The first mass production car powered by Wankel engine was released in 1967 by the Japanese manufacture Mazda. It was a reference design, twin –rotor 9 82cc, outputting 110 hp. That made the 2000 pounds Cosmo model pretty zippy. Mazda quickly introduced 2 more models in 1970 and with prices significantly lower than its competition Mazda’s success rapidly increased. Seeing the growing interest, 2 of the largest automobile manufactures in the world– General Motors and Mercedes-Benz – purchased license to produce vehicle with this technology. General Motors even had a Corvette on the way, when the 1973 oil crisis changed everything over. The Wankel engine at the time was less fuel efficient, so the sales suddenly dropped down so low that Mazda was a step away from bankrupt. They changed their strategy and rotary cars became a special line, instead of mainstream. Then and now, Mazda is the only manufacture to truly stand by this technology. It improved it radically in terms of output and fuel efficiency. Their last generation engine, called Renesis, used since 2003 in RX-8, has the same output like the previous generation 250hps, red line topping at 10 000 rpms. However, it is naturally aspirated, where the previous one was twin-turbo charged. The Renesis is also 25% more efficient. Sadly it wasn’t enough, and the RX-8 was discontinued in August 2011, with no successor announced. With the slow pace of its evolution, I hope we can see the next generation at the end of this decade. Mazda and the Wankel engine have won many awards and races. The most prestige one is the success in 1991 in the annual â€Å"24 hours of Le Mans†, leaving behind drivers and teams with traditions like Mercedes, Jaguar and the frequent winner Porsche. The four-rotor engine outputting 700 hp lead the team first to the finish, regardless their start position – 55. As William Welch states, in his recent publication in USA Today, â€Å"the only Japanese car and only non-piston engined car to win the grueling French race† (William M. Welch, USA Today 08/23/2011). â€Å"Sanctioning bodies outlawed the engine after the win at Le Mans† and close the history of Wankel powered cars at this scramble (William M. Welch, USA Today 08/23/2011). That win however, confirmed the Wankel reputation of power and durability. Even though the Renesis was a big step forward, it was still a step behind the longer lived piston engine in terms of fuel economy. That was its only drawback, but enough to turn a lot of people away. Not so many had the chance to experience the fun side of this fast revving motor. Fossil fuels, like gasoline, are fated to become extremely rear and expensive and it looks like Mazda engineers are getting prepared for this scenario. In interview for Reuters news agency from 2007 Mazda executive Nobuhiro Hayama revealed their new strategy: â€Å"Researchers at Japanese carmaker Mazda think cars will in future run on water component – hydrogen. †¦the advantage hydrogen fuel was that it could be used in internal combustion engines. However †¦ there is a risk of abnormal combustion. This could be solved by using rotary engines† (Tokyo Reuters Oct 22 2007). That means that a slightly modified RX-8 could reborn and satisfy the need of cheaper run and exciting pull, equipped with â€Å"two fuel tanks, though† (Tokyo Reuters Oct 22 2007). We would expect the price to remain the same, since no direct modification to the engine is needed, and the car has paid of its investments already. It looks like a bright future for the Wankel. Removed paragraphs Taking in consideration the minimum moving parts of the Wankel engine, the aerocraft industry quickly realized its lifesaving advantage. In case of internal engine damage the engine would not fail right away. It will continue delivering power that will decrease with time. Its weight and size made it preferable for many small plane manufactures. It let the engineers improve aero dynamics of the plane nose, due to the smaller engine. The first complete Wankel engine was reviled in 1956 by its engineer Felix Wankel (The Columbia Encyclopedia – internal-combustion engine). Since then, the engine received many improvements. The main contributor is the Japanese manufacture Mazda that started a line of sport cars with Wankel engines in mid-1960. The first model, named Cosmo, had a good success and two more models were released in 1970. Seeing the potential in this relatively new technology, a few more automobile manufactures build their own sport car prototypes including Mercedes-Benz and General Motors. The second had a prototype of the legendary Corvette. As every invention, this one also has disadvantage – fuel efficiency. Hit by the first oil crisis in 1973, all manufactures except Mazda canceled their plans for a production Wankel powered car. Even more Mazda almost bankrupted, since they completely had abandoned reciprocating (piston) engines. Today Mazda is the only one to mass produce Wankel engine cars, and it has made huge, but slow progress in this field. The last generation named RX-8 had achieved better output with lower fuel consumption – huge step forward from the previous RX-7.

Introduction to the Lapita Cultural Complex

Introduction to the Lapita Cultural Complex The Lapita culture is the name given to the artifactual remains associated with the people who settled the area east of the Solomon Islands called Remote Oceania between 3400 and 2900 years ago. The earliest Lapita sites are located in the Bismarck islands, and within 400 years of their founding, the Lapita had spread over an area of 3,400 kilometers, stretching through the Solomon Islands, Vanuatu, and New Caledonia, and eastward to Fiji, Tonga, and Samoa. Located on small islands and the coasts of larger islands, and separated from one another by as much as 350 kilometers, the Lapita lived in villages of stilt-legged houses and earth-ovens, made distinctive pottery, fished and exploited marine and aquacultural resources, raised domestic chickens, pigs and dogs, and grew fruit- and nut-bearing trees. Lapita Cultural Attributes Pottery making workshop demonstrating Lapita pottery styles as part of Heritage Month 2017 in New Caledonia. Gà ©rard Lapita pottery consists of mostly plain, red-slipped, coral sand-tempered wares; but a small percentage are ornately decorated, with intricate geometric designs incised or stamped onto the surface with a fine-toothed dentate stamp, perhaps made of turtle or clamshell. One often-repeated motif in Lapita pottery is what appears to be stylized eyes and nose of a human or animal face. The pottery is built, not wheel thrown, and low-temperature fired. Other artifacts found at Lapita sites include shell tools including fishhooks, obsidian, and other cherts, stone adzes, personal ornaments such as beads, rings, pendants and carved bone. That artifacts are not completely uniform throughout Polynesia, but rather seem to be spatially variable. Tattooing The practice of tattooing has been reported in ethnographic and historical records throughout the Pacific, by one of two methods: cutting and piercing. In some cases, a series of very small cuts is made to create a line, and then pigment was rubbed into the open wound. A second method involves the use of a sharp point which is dipped into the prepared pigment and then used to pierce the skin. Evidence for tattooing in Lapita cultural sites has been identified in the form of small flake points made by alternating retouch. These tools sometimes categorized as gravers have a typically square body with a point raised well above the body. A 2018 study combining use-wear and residue analysis was conducted by Robin Torrence and colleagues on a collection of 56 such tools from seven sites. They found a considerable variation across time and space as to how the tools were used to intentionally introduce charcoal and ochre into wounds to create a permanent mark on the skin. Origins of the Lapita Young men in canoes in Northwest Malakula, Vanuatu.   Russell Gray Heidi Colleran (Max Planck Institute for the Science of Human History) In 2018, a multidisciplinary study of DNA by the Max Planck Institute for the Science of Human History reported support for ongoing multiple explorations of greater Oceania beginning about 5,500 years ago. The study led by Max Planck researcher Cosimo Posth looked at the DNA of 19 ancient individuals across Vanuatu, Tonga, French Polynesia and the Solomon islands, and 27 inhabitants of Vanuatu. Their results indicate that the earliest Austronesian expansion began 5,500 years ago, starting from modern-day Taiwan, and ultimately carrying people as far westward as far as Madagascar and eastward to Rapa Nui. About 2,500 years ago, people from the Bismarck archipelago began arriving on Vanuatu, in multiple waves, marrying into the Austronesian families. The continual influx of people from the Bismarcks must have been fairly small, because islanders today still speak Austronesian, rather than Papuan, as would be expected, given that the initial genetic Austronesian ancestry seen in the ancient DNA has been almost completely replaced in the modern residents.   Decades of research have identified obsidian outcrops used by the Lapita in the Admiralty Islands, West New Britain, Fergusson Island in the D’Entrecasteaux Islands, and the Banks Islands in Vanuatu. Obsidian artifacts found in datable contexts on Lapita sites throughout Melanesia have allowed researchers to refine the previously established massive colonization efforts of the Lapita sailors. Archaeological Sites Lapita, Talepakemalai in the Bismarck Islands; Nenumbo in the Solomon Islands; Kalumpang (Sulawesi); Bukit Tengorak (Sabah); Uattamdi on Kayoa Island; ECA, ECB aka Etakosarai on Eloaua Island; EHB or Erauwa on Emananus Island; Teouma on Efate Island in Vanuatu; Bogi 1, Tanamu 1, Moriapu 1, Hopo, in Papua New Guinea Sources Johns, Dilys Amanda, Geoffrey J. Irwin, and Yun K. Sung. An Early Sophisticated East Polynesian Voyaging Canoe Discovered on New Zealands Coast. Proceedings of the National Academy of Sciences 111.41 (2014): 14728–33. Print.Matisoo-Smith, Elizabeth. Ancient DNA and the Human Settlement of the Pacific: A Review. Journal of Human Evolution 79 (2015): 93–104. Print.Posth, Cosimo, et al. Language Continuity Despite Population Replacement in Remote Oceania. Nature Ecology Evolution 2.4 (2018): 731–40. Print.Skelly, Robrt, et al. Tracking Ancient Beach-Lines Inland: 2600-Year-Old Dentate-Stamped Ceramics at Antiquity 88.340 (2014): 470–87. Print.Hopo, Vailala River Region, Papua New Guinea.Specht, Jim, et al. Deconstructing the Lapita Cultural Complex in the Bismarck Archipelago. Journal of Archaeological Research 22.2 (2014): 89–140. Print.Torrence, Robin, et al. Tattooing Tools and the Lapita Cultural Complex. Archaeology in Oceania 53.1 (2018): 58â⠂¬â€œ73. Print.Valentin, Frà ©dà ©rique, et al. Early Lapita Skeletons from Vanuatu Show Polynesian Craniofacial Shape: Implications for Remote Oceanic Settlement and Lapita Origins. Proceedings of the National Academy of Sciences 113.2 (2016): 292–97. Print.

Maritime Manegement 2 Essay Example | Topics and Well Written Essays - 1500 words

Maritime Manegement 2 - Essay Example The strength of the economy, its location, resources, population size and political influence contribute to its power. During the establishment of the China’s economy that is in 1949, the economy was modeled on Soviet model as suggested by Wang and Chin-Keong (2004). This was after the communist revolution. As a result, China ended up its connection with the capitalist world. China’s economic model involved the formation of state controlled heavy industries which were financed by capital acquired from agriculture. China substituted its imports with domestic goods so as to acquire foreign exchange to buy goods and technology. China’s economy has contributed a lot to the development of the shipping operations which are part of their economy. China is one of the countries with the most ample shipping resources. The China’s coastal areas offer the highest percentage of the countries imports and exports value. This is an advantage as it creates a good environme nt for fast and healthy development of the countries maritime industry. With the development of the maritime industries, the economy of China has experienced continuous and strong growth momentum. This has led to an increase in both trans-regional and multinational trading systems. China’s maritime industry has been growing rapidly to meet the expanding requirements for foreign exchange. Since the adoption of its reforms and the open policies, the international shipping industry is now increasing while promoting healthy development of the industry. China’s economy has steadily grown since 1990. The steady growth in economic demands has brought a great opportunity for Chinese shipping industry development. China is currently one of the world’s largest countries capable of offering comprehensive package of shipping activities in the ocean. It fleets cover a greater range including traditional bulk and more value added tonnages. The China’s growing economy h as effects on transport routes between China and Europe. The economy has also contributed to the opening of the Arctic Ocean summer route for both countries according to Liu (2009). To provide healthy transportation of containers, there are number of challenges shipping industry should deal with. One of the challenges is how to survive the Arctic’s harsh climate. The development strategy behind this is enhancing the coordination between the two countries towards improving the condition of the Arctic Ocean. Secondly is the issue of occurring changes in the Arctic Ocean and its commercial implications. The growing Chinese economy is partnering with the Europe to counter the challenge. In Europe, china is the second major partner in trading activities after the US. For both countries that is China and Europe, maritime transport makes a vital contribution to their energy strategies. This has been through establishing more shipping routes and energy diversification. China and Euro pe have economic interest aimed at developing their routes of transport along the coast of northern Russia. To ensure safety in the Arctic region, Europe and China should improve their corporation in research activities. Should also enhance information exchange and add on the formation of reliable systems of monitoring and forecasting. Both countries should also provide safe and effective maritime operations in the Arctic Ocean. China’s political activities have developed with the expansion on the countries