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List of Gliders (D)
This is a list of gliders/sailplanes of the world, (this reference lists all gliders with references, where available) Note: Any aircraft can glide for a short time, but gliders are designed to glide for longer.
  • 726
  • 04 Nov 2022
Topic Review
Dynamic Positioning
Dynamic positioning (DP) is a computer-controlled system to automatically maintain a vessel's position and heading by using its own propellers and thrusters. Position reference sensors, combined with wind sensors, motion sensors and gyrocompasses, provide information to the computer pertaining to the vessel's position and the magnitude and direction of environmental forces affecting its position. Examples of vessel types that employ DP include, but are not limited to, ships and semi-submersible mobile offshore drilling units (MODU), oceanographic research vessels, cable layer ships and cruise ships. The computer program contains a mathematical model of the vessel that includes information pertaining to the wind and current drag of the vessel and the location of the thrusters. This knowledge, combined with the sensor information, allows the computer to calculate the required steering angle and thruster output for each thruster. This allows operations at sea where mooring or anchoring is not feasible due to deep water, congestion on the sea bottom (pipelines, templates) or other problems. Dynamic positioning may either be absolute in that the position is locked to a fixed point over the bottom, or relative to a moving object like another ship or an underwater vehicle. One may also position the ship at a favorable angle towards wind, waves and current, called weathervaning. Dynamic positioning is used by much of the offshore oil industry, for example in the North Sea, Persian Gulf, Gulf of Mexico, West Africa, and off the coast of Brazil . There are currently more than 1800 DP ships.
  • 1.6K
  • 04 Nov 2022
Topic Review
Medical Thermometer
A medical thermometer (also called clinical thermometer) is used for measuring human or animal body temperature. The tip of the thermometer is inserted into the mouth under the tongue (oral or sub-lingual temperature), under the armpit (axillary temperature), into the rectum via the anus (rectal temperature), into the ear (tympanic temperature), or on the forehead (temporal temperature).
  • 1.2K
  • 04 Nov 2022
Topic Review
AMC 34
The AMC 34 was a French tank built originally for the French Army cavalry units. Its production was cut short, and the few vehicles produced were out of service by the time of the Battle of France in the Second World War.
  • 586
  • 04 Nov 2022
Topic Review
Chemical Analysis of Synthetic Antioxidants in Foodstuffs
The information obtained by the systematic search in ScienceDirect® databases, indicated the predominance of the use of separation chromatography, followed by detection techniques in the development of analytical methods for the detection of phenolic antioxidants in foodstuffs. This is because these techniques allow the simultaneous determination of different types of antioxidants, through the separation of these compounds at different stages of a column, thus obtaining different retention times, which are related to the physicochemical characteristics of the antioxidants and their interaction between the stationary and mobile phase. After the separation, the antioxidants are identified and quantified using specific chromatographic detectors, such as ultraviolet–visible, diode array, thermal conductivity, and mass spectroscopy, resulting in a suitable sensitivity and selectivity. However, separation and detection chromatographic, despite being very accurate in the detection of antioxidants, have as their main disadvantage the use of large amounts of organic solvents or inert gases, with elevated purity and, consequently, high cost. Additionally, the use of these techniques requires rigorous steps of extraction and cleanup to prepare the foodstuff samples for analysis, remove interference compounds, and/or preconcentrate the antioxidants to obtain reliable information. Extraction steps can increase the time and costs in the analysis, promote a reduction in the analytical frequency, and generate a great quantity of residues, which goes against a very important principle, taken very seriously today, green chemistry, which orients the reduction or elimination of toxic residues in chemical products and processes, including all cycles of a chemical, in its design, manufacture, use, and final disposal.
  • 711
  • 04 Nov 2022
Topic Review
Sustainable Energy Systems in Southern African Development Community
The Southern African Development Community (SADC) region includes all the countries located in the southernmost region of Africa, with the Democratic Republic of Congo on the northern boundary of the region. In 2017, more than 341 million people were living in SADC, representing around 33% of SSA’s total population of 1.02 billion, and with an annual growth rate of 2%.  Hydropower is the main renewable energy source in most member states, including Angola, the Democratic Republic of Congo, Lesotho, Malawi, Mozambique, Namibia, and Zambia. Therefore, to accelerate energy access for a higher share of the population, countries like South Africa, Botswana, and Zimbabwe are continuing to exploit mainly non-renewable energy sources, particularly coal. Additionally, SADC needs to face the reduction of GHG emissions to ensure sustainability, and to this end, every effort should be made to guarantee carbon neutrality and a zero-carbon economy.
  • 471
  • 04 Nov 2022
Topic Review
Occupational Safety and Health Management System Standards
Occupational accidents present a momentous effect on human well-being and, in addition, create large costs in any country’s social health/insurance system. Moreover, the topic of “safety and health” (OSH, OS&H) or “health and safety” (OHS, OH&S) concerning labor (or occupational work) is one of the most significant issues in any corporation. OSHMS systems were developed as a consequence of a plethora of several and severe industrial accidents throughout the decades of the 1970s and 1980s (for example, the Flixborough accident in 1974, the Seveso incident in 1976, and the Piper Alpha disaster in 1987). Thorough examinations of these events revealed insufficiencies in the dominant techniques for the regulation and the management of OSH and determined the necessity to use approaches that methodically address both engineering and educational action. The proliferation of OSH management systems, which have been used worldwide since the 1990s, has dramatically increased the concentration of performance measurement methods, tools, and techniques.
  • 1.6K
  • 04 Nov 2022
Topic Review
CO2 Sequestration in Geological Formations
The geological storage of carbon dioxide (CO2) is the most effective and, in many cases, the only viable short- to medium-term alternative for considerably moving towards CO2 sequestration in geological sinks and, thus, lowering net carbon emissions into the atmosphere.
  • 888
  • 04 Nov 2022
Topic Review
Skiffing
Skiffing refers to the sporting and leisure activity of rowing (or more correctly sculling) a Thames skiff. The skiff is a traditional hand built clinker-built wooden craft of a design which has been seen on the River Thames and other waterways in England and other countries since the 19th century. Sculling is the act of propelling the boat with a pair of oars (or blades), as opposed to rowing which requires both hands on a single oar.
  • 661
  • 03 Nov 2022
Topic Review
Advanced Gemini
Advanced Gemini is a number of proposals that would have extended the Gemini program by the addition of various missions, including manned low Earth orbit, circumlunar and lunar landing missions. Gemini was the second manned spaceflight program operated by NASA, and consisted of a two-seat spacecraft capable of maneuvering in orbit, docking with unmanned spacecraft such as Agena Target Vehicles, and allowing the crew to perform tethered extra-vehicular activities. A range of applications were considered for Advanced Gemini missions, including military flights, space station crew and logistics delivery, and lunar flights. The Lunar proposals ranged from reusing the docking systems developed for the Agena target vehicle on more powerful upper stages such as the Centaur, which could propel the spacecraft to the Moon, to complete modifications of the Gemini to enable it to land on the Lunar surface. Its applications would have ranged from manned lunar flybys before Apollo was ready, to providing emergency shelters or rescue for stranded Apollo crews, or even replacing the Apollo program. Some of the Advanced Gemini proposals used "off-the-shelf" Gemini spacecraft, unmodified from the original program, while others featured modifications to allow the spacecraft to carry more crew, dock with space stations, visit the Moon, and perform other mission objectives. Other modifications considered included the addition of wings or a parasail to the spacecraft, in order to enable it to make a horizontal landing.
  • 525
  • 03 Nov 2022
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