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Topic Review
Macchi C.205
The Macchi C.205 Veltro (Italian: Greyhound) (also known as MC.205, "MC" standing for "Macchi Castoldi") was an Italian World War II fighter aircraft built by the Aeronautica Macchi. Along with the Reggiane Re.2005 and Fiat G.55, the Macchi C.205 was one of the three "Serie 5" Italian fighters built around the powerful Daimler-Benz DB 605 engine. The C.205 was a development of the earlier C.202 Folgore. With a top speed of some 640 km/h (400 mph) and equipped with a pair of 20 mm cannon as well as 12.7 mm Breda machine guns, the Macchi C.205 Veltro was highly respected by Allied and Axis pilots alike. Widely regarded as one of the best Italian aircraft of World War II, it proved to be extremely effective, destroying a large number of Allied bombers. The Macchi C. 205 proved capable of meeting fighters such as the North American P-51D Mustang on equal terms, which encouraged the Luftwaffe to use a number of these aircraft to equip one Gruppe. While the C.205 was able to match the best Allied opponents in speed and manoeuvrability, it was introduced late in the conflict. Due to the limitations of the Italian war economy, only a small production run was delivered before the end of the war. Like the Spitfire, the Veltro was tricky in its construction and slow to build. Italy's highest scoring ace, Adriano Visconti, achieved 11 of his 26 credited victories in the few weeks he was able to fly the Veltro, with the top scoring Sergente Maggiore pilota Luigi Gorrini shooting down 14 enemy aircraft plus six damaged with the C.205.
  • 1.1K
  • 28 Oct 2022
Topic Review
CEA-708
CEA-708 is the standard for closed captioning for ATSC digital television (DTV) streams in the United States and Canada . It was developed by the Electronic Industries Alliance. Unlike RLE DVB and DVD subtitles, CEA-708 captions are low bandwidth and textual like traditional EIA-608 captions and EBU Teletext subtitles. However, unlike EIA-608 byte pairs, CEA-708 captions are not able to be modulated on an ATSC receiver's NTSC VBI line 21 composite output and must be pre-rendered by the receiver with the digital video frames, they also include more of the Latin-1 character set, and include stubs to support full UTF-32 captions, and downloadable fonts. CEA-708 caption streams can also optionally encapsulate EIA-608 byte pairs internally, a fairly common usage. CEA-708 captions are injected into MPEG-2 video streams in the picture user data. The packets are in picture order, and must be rearranged just like picture frames are. This is known as the DTVCC Transport Stream. It is a fixed-bandwidth channel that has 960 bit/s typically allocated for backward compatible "encapsulated" Line 21 captions, and 8640 bit/s allocated for CEA-708 captions, for a total of 9600 bit/s. The ATSC A/53 Standard contains the encoding specifics. The main form of signalling is via a PSIP caption descriptor which indicates the language of each caption and if formatted for "easy reader" (3rd grade level for language learners) in the PSIP EIT on a per event basis and optionally in the H.222 PMT only if the video always sends caption data. CEA-708 caption decoders are required in the U.S. by FCC regulation in all 13" (33 cm) diagonal or larger digital televisions. Further, some broadcasters are required by FCC regulations to caption a percentage of their broadcasts.
  • 1.1K
  • 20 Oct 2022
Topic Review
Braid Hollow Fiber Membranes
Hollow fiber membranes (HFMs) are a good candidate for the membrane separation process due to desirable properties such as high permeability and surface area, good filtration efficiency, small footprint, etc. However, they are often possible to break during the high-pressure cleaning and aeration process. Tubular braids a supported is proposed to improve the mechanical strength of HFMs due to high tensile strength.
  • 1.1K
  • 10 Dec 2021
Topic Review
Counterprogramming
In broadcast programming, counterprogramming is the practice of offering television programs to attract an audience from another television station airing a major event. It is also referred when programmers offer something different from the rival’s program as an alternative, to increase the audience size.
  • 1.1K
  • 28 Sep 2022
Topic Review
Transport Membrane Condenser Heat Exchangers
The transport membrane condensers (TMC) process can be considered as a hybrid of a heat exchanger and membrane condensers. 
  • 1.1K
  • 12 Jan 2021
Topic Review
Mechanical Properties of FDM
Fused deposition modeling (FDM) uses thermoplastic materials to print parts layer by layer. Usually, a (or several) continuous filament made of thermoplastic polymer is heated to the point of viscous state and extruded layer by layer on a platform to build the part. The thermo-plasticity properties of the material assist the fusing of layers together as well as the solidification process while the temperature is decreasing. Bonding between the layers will be generated due to the interaction of the molecules when one layer stays in a molten state and bound to the solid layer while solidifying. However, voids might appear between the layers due to the fast freezing of molten fibers or the lack of overlap between the extruded material and the solidified material. Therefore, these bonds exhibit mechanical properties unlike those created by the conventional manufacturing process and therefore it is difficult to predict the mechanical properties of FDM printed parts.
  • 1.1K
  • 01 Jun 2021
Topic Review
Indoor Thermal Comfort
A neutral or comfortable environment is an environment that allows metabolic heat production to be balanced with heat exchange (loss and/or gain) from the air around the worker. Outside this situation of balance, there may be adverse situations in which the exchange of heat energy constitutes a risk to the person’s health, since even taking into account the body’s thermoregulation mechanisms, they cannot maintain a constant and adequate internal temperature. Even though the milder climate scenario and constant evolution of thermal building regulation are in light of European initiatives, in Portugal, there are few houses where occupants can remain all the time in perfectly comfortable temperature conditions without resorting to heating or cooling. According to the Long Term Strategy for the Renewal of Buildings (ELPRE), this results from the combination of several factors, namely, low energy use for air conditioning compared to energy needs and aged building stock with poor energy performance. In fact, around 70% of the dwellings currently certified have low energy efficiency (C or less).
  • 1.1K
  • 01 Sep 2022
Topic Review
Wastewater Treatment by Catalytic Wet Peroxidation
Nowadays, there is an increasing interest in the development of promising, efficient, and environmentally friendly wastewater treatment technologies. Among them are the advanced oxidation processes (AOPs), in particular, catalytic wet peroxidation (CWPO), assisted or not by radiation. One of the challenges for the industrial application of this process is the development of stable and efficient catalysts, without leaching of the metal to the aqueous phase during the treatment. Gold catalysts, in particular, have attracted much attention from researchers because they show these characteristics. Recently, numerous studies have been reported in the literature regarding the preparation of gold catalysts supported on various supports and testing their catalytic performance in the treatment of real wastewaters or model pollutants by CWPO. This review summarizes this research; the properties of such catalysts and their expected effects on the overall efficiency of the CWPO process, together with a description of the effect of operational variables (such as pH, temperature, oxidant concentration, catalyst, and gold content). In addition, an overview is given of the main technical issues of this process aiming at its industrial application, namely the possibility of using the catalyst in continuous flow reactors. Such considerations will provide useful information for a faster and more effective analysis and optimization of the CWPO process.
  • 1.1K
  • 14 May 2020
Topic Review
Nanocatalysts Used in AOPs for Wastewater Treatment
The increase in population demands for industrialization and urbanization which led to the introduction of novel hazardous chemicals in our environment. The most significant parts of these harmful substances found in water bodies remain in the background, causing a health risk to humans and animals. It is critical to remove these toxic chemicals from the wastewater to keep a cleaner and greener environment. Hence, wastewater treatment is a challenging area these days to manage liquid wastes effectively. Therefore, scientists are in search of novel technologies to treat and recycle wastewater, and nanotechnology is one of them, thanks to the potential of nanoparticles to effectively clean wastewater while also being ecologically benign. Advanced oxidation processes (AOPs) have been extensively studied. Advanced oxidation processes can be defined as the processes and technologies which involve the generation of active species such as hydroxyl radicals (•OH) which act as efficient oxidants to decompose pollutants in wastewater treatment. 
  • 1.1K
  • 28 Jul 2022
Topic Review
Piezoelectric Material
Piezoelectric materials can be called“the top of the crop” of smart materials. Piezoelectric materials have emerged as the most researched materials for practical applications among the numerous smart materials. They owe it to a few main reasons, including low cost, high bandwidth of service, availability in a variety of formats, and ease of handling and execution. Several authors have used piezoelectric materials as sensors and actuators to effectively control structural vibrations, noise, and active control, as well as for structural health monitoring, over the last three decades. These studies cover a wide range of engineering disciplines, from vast space systems to aerospace, automotive, civil, and biomedical engineering.
  • 1.1K
  • 24 May 2021
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