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Topic Review
HMS Lady Nelson (1798)
His Majesty's Armed Survey Vessel Lady Nelson was commissioned in 1799 to survey the coast of Australia. At the time large parts of the Australian coast were unmapped and Britain had claimed only part of the continent. The British Government were concerned that, in the event of settlers of another European power becoming established in Australia, any future conflict in Europe would lead to a widening of the conflict into the southern hemisphere to the detriment of the trade that Britain sought to develop. It was against this background that Lady Nelson was chosen to survey and establish sovereignty over strategic parts of the continent. Lady Nelson left Portsmouth on 18 March 1800 and arrived at Sydney on 16 December 1800 after having been the first vessel to reach the east coast of Australia via Bass Strait. Prior to that date all vessels had sailed around the southern tip of Tasmania to reach their destination. Lady Nelson's survey work commenced shortly after her arrival at Sydney, initially in the Bass Strait area. She was involved in the discovery of Port Phillip, on the coast of Victoria, in establishing settlements on the River Derwent and at Port Dalrymple in Tasmania, at Newcastle and Port Macquarie in New South Wales, and on Melville Island off the north coast of the continent.
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Topic Review
GRACE and GRACE-FO
The Gravity Recovery and Climate Experiment (GRACE) was a joint mission of NASA and the German Aerospace Center (DLR). Twin satellites took detailed measurements of Earth's gravity field anomalies from its launch in March 2002 to the end of its science mission in October 2017. The Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) is a continuation of the mission on near-identical hardware, launched in May 2018. By measuring gravity anomalies, GRACE showed how mass is distributed around the planet and how it varies over time. Data from the GRACE satellites is an important tool for studying Earth's ocean, geology, and climate. GRACE was a collaborative endeavor involving the Center for Space Research at the University of Texas at Austin, NASA's Jet Propulsion Laboratory, the German Aerospace Center and Germany's National Research Center for Geosciences, Potsdam. The Jet Propulsion Laboratory was responsible for the overall mission management under the NASA ESSP (Earth System Science Pathfinder) program. The principal investigator is Byron Tapley of the University of Texas Center for Space Research, and the co-principal investigator is Christoph Reigber of the GeoForschungsZentrum (GFZ) Potsdam. The two GRACE satellites (GRACE-1 and GRACE-2) were launched from Plesetsk Cosmodrome, Russia, on a Rockot (SS-19 + Breeze upper stage) launch vehicle on 17 March 2002. The spacecraft were launched to an initial altitude of approximately 500 km at a near-polar inclination of 89°. During normal operations, the satellites were separated by 220 km along their orbit track. This system was able to gather global coverage every 30 days. GRACE far exceeded its 5-year design lifespan, operating for 15 years until the decommissioning of GRACE-2 on 27 October 2017. Its successor, GRACE-FO, was successfully launched on 22 May 2018. In 2019, a glacier in West Antarctica was named after the GRACE mission.
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Topic Review
Variable-Pitch Propeller
A variable-pitch propeller or controllable-pitch propeller (CPP) is a type of propeller with blades that can be rotated around their long axis to change the blade pitch. Reversible propellers—those where the pitch can be set to negative values—can also create reverse thrust for braking or going backwards without the need to change the direction of shaft revolution.
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Topic Review
Capella (Engineering)
Capella is an open-source solution for model-based systems engineering (MBSE). Hosted at polarsys.org, this solution provides a process and tooling for graphical modeling of systems, hardware or software architectures, in accordance with the principles and recommendations defined by the Arcadia method. Capella is an initiative of PolarSys, one of several Eclipse Foundation working groups.
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Topic Review
Electrically Powered Spacecraft Propulsion
An electrically powered spacecraft propulsion system uses electrical, and possibly also magnetic fields, to change the velocity of a spacecraft. Most of these kinds of spacecraft propulsion systems work by electrically expelling propellant (reaction mass) at high speed. Electric thrusters typically use much less propellant than chemical rockets because they have a higher exhaust speed (operate at a higher specific impulse) than chemical rockets. Due to limited electric power the thrust is much weaker compared to chemical rockets, but electric propulsion can provide thrust for a longer time. Electric propulsion is now a mature and widely used technology on spacecraft. Russia n satellites have used electric propulsion for decades. (As of 2019), over 500 spacecraft operated throughout the Solar System use electric propulsion for station keeping, orbit raising, or primary propulsion. In the future, the most advanced electric thrusters may be able to impart a delta-v of 100 km/s, which is enough to take a spacecraft to the outer planets of the Solar System (with nuclear power), but is insufficient for interstellar travel. An electric rocket with an external power source (transmissible through laser on the photovoltaic panels) has a theoretical possibility for interstellar flight. However, electric propulsion is not suitable for launches from the Earth's surface, as it offers too little thrust. On a journey to Mars, an electrically powered ship might be able to carry 70% of its initial mass to the destination, while a chemical rocket could carry only a few percent.
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Topic Review
Mahindra & Mahindra
Mahindra & Mahindra Limited is an India multinational vehicle Automotive industry corporation headquartered in Mumbai , Maharashtra, India. It was established in 1945 as Muhammad & Mahindra and later renamed as Mahindra and Mahindra. It is one of the largest vehicle manufacturers by production in India and the largest manufacturer of tractors in the world. It is a part of the Mahindra Group, an Indian conglomerate. It was ranked 17th on a list of top companies in India by Fortune India 500 in 2018. Its major competitors in the Indian market include Maruti Suzuki and Tata Motors.
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Topic Review
Centralised Generation
Centralised generation refers the common process of electricity generation through large-scale centralised facilities, through Transmission lines to consumer. These facilities are usually located far away from consumers and distribute the electricity through high voltage transmission lines to a substation where it is then distributed to consumers. The basic concept being that incredibly large stations create electricity for a large group of people. The Vast majority of electricity used in Australia as well as the United States is created from Centralised Generation. Most Centralised Power Generation comes from large power plants run by fossil fuels such as coal or natural gas. Nuclear or large hydroelectricity plants are also commonly used. Many disagree with the processes of Centralised Generation as it often relies on electrical generation through processes of the combustion of fossil fuels, which are bad for the environment. However unsustainable the current system is, it is by far the most widely used, reliable and efficient system that is currently in use. Centralised Generation is fundamentally the opposite of distributed generation. Distributed generation is the small-scale generation of electricity to smaller groups of consumers. This can also include independently producing electricity by either solar or wind power. In recent years Distributed generation as has seen a spark in popularity due to its propensity to use renewable energy generation methods such as wind and solar.
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Topic Review
King Abdulaziz International Airport
King Abdulaziz International Airport (KAIA) (Arabic: مطار الملك عبدالعزيز الدولي) (IATA: JED, ICAO: OEJN) is a Saudi international airport located 19 km to the north of Jeddah. Named after King Abdulaziz Al Saud and inaugurated in 1981, the airport is the busiest airport of Saudi Arabia and the third-largest airport in the kingdom. The airport's Hajj Terminal was specially built for Muslim pilgrims going to Mecca annually on the Hajj. It is one of the largest in the world, and can handle 80,000 passengers at the same time.
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Biography
William H.C. Whiting
William Henry Chase Whiting (March 22, 1824 – March 10, 1865) was a United States Army officer who resigned after 16 years of service in the Army Corps of Engineers to serve in the Confederate States Army during the American Civil War. He was wounded at the Second Battle of Fort Fisher by a musket ball to his leg, and died in prison camp on March 10, 1865, of dysentery. William Whiting was
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Topic Review
Deep Foundation
A deep foundation is a type of foundation that transfers building loads to the earth farther down from the surface than a shallow foundation does to a subsurface layer or a range of depths. A pile or piling is a vertical structural element of a deep foundation, driven or drilled deep into the ground at the building site. There are many reasons that a geotechnical engineer would recommend a deep foundation over a shallow foundation, such as for a skyscraper. Some of the common reasons are very large design loads, a poor soil at shallow depth, or site constraints like property lines. There are different terms used to describe different types of deep foundations including the pile (which is analogous to a pole), the pier (which is analogous to a column), drilled shafts, and caissons. Piles are generally driven into the ground in situ; other deep foundations are typically put in place using excavation and drilling. The naming conventions may vary between engineering disciplines and firms. Deep foundations can be made out of timber, steel, reinforced concrete or prestressed concrete.
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