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Topic Review
Demolition Waste Management
Demolition waste generation has grown throughout the years with the urbanization process. The environmental impacts of demolition waste generation and related waste treatment have attracted global attention from the government, industry, and academia. With advancements in building information modelling and life cycle assessment methods, it provides possible solutions to managing demolition waste in a more systematic way.
  • 600
  • 06 Dec 2021
Topic Review
DEMOnstration Power Station
DEMO (DEMOnstration Power Station) is a proposed nuclear fusion power station that is intended to build upon the ITER experimental nuclear fusion reactor. The objectives of DEMO are usually understood to lie somewhere between those of ITER and a "first of a kind" commercial station, sometimes referred to as PROTO. While there is no clear international consensus on exact parameters or scope, the following parameters are often used as a baseline for design studies: DEMO should produce at least 2 gigawatts of fusion power on a continuous basis, and it should produce 25 times as much power as required for breakeven. DEMO's design of 2 to 4 gigawatts of thermal output will be on the scale of a modern electric power station. To achieve its goals, DEMO must have linear dimensions about 15% larger than ITER, and a plasma density about 30% greater than ITER. As a prototype commercial fusion reactor, it was estimated in 2006, that DEMO could make fusion energy available by 2033, but has now been delayed. It is estimated that subsequent commercial fusion reactors could be built for about a quarter of the cost of DEMO.
  • 503
  • 10 Oct 2022
Topic Review
Denoising Techniques for High-Performance MEMS Microphones
The MEMS (Micro-Electro-Mechanical Systems) microphone is a representative device among the MEMS family, which has attracted substantial research interest, and those tailored for human voice have earned distinct success in commercialization. With the advancement of microphone technology and the market, microphones have become carriers for various intelligent applications, therefore demanding higher criteria in noise suppression. For instance, a hearing aid should suppress ambient noise while delivering relevant sounds to the user. Additionally, in specific environments, the noise performance of microphones is crucial for communication and intelligent voice-related needs such as voice activation and speech recognition.
  • 296
  • 11 Mar 2024
Topic Review
Density Meter
A density meter, also known as a densimeter, is a device that measures the density. Density is usually abbreviated as either [math]\displaystyle{ \rho }[/math] or [math]\displaystyle{ D }[/math]. Typically, density either has the units of [math]\displaystyle{ kg/m^3 }[/math] or [math]\displaystyle{ lb/ft^3 }[/math]. The most basic principle of how density is calculated is by the formula: Where: Many density meters can measure both the wet portion and the dry portion of a sample. The wet portion comprises the density from all liquids present in the sample. The dry solids comprise solely of the density of the solids present in the sample. A density meter does not measure the specific gravity of a sample directly. However, the specific gravity can be inferred from a density meter. The specific gravity is defined as the density of a sample compared to the density of a reference. The reference density is typically of that of water. The specific gravity is found by the following equation: Where: Density meters come in many varieties. Different types include: nuclear, coriolis, ultrasound, microwave, and gravitic. Each type measures the density differently. Each type has its advantages and drawbacks. Density meters have many applications in various parts of various industries. Density meters are used to measure slurries, sludges, and other liquids that flow through the pipeline. Industries such as mining, dredging, wastewater treatment, paper, oil, and gas all have uses for density meters at various points during their respective processes.
  • 869
  • 25 Oct 2022
Topic Review
Dental Prosthetics or Implants
Dental implants or prosthetics are used to replace missing teeth and treat partially or fully damaged teeth. The dental implant success rate is more than 90% after ten years, ensuring long-term reliability. There are three primary types of dental implants: endosteal or endosseous, subperiosteal, and transosteal. Dental implants are a continuously growing market for both medical and cosmetic purposes. Modern science has allowed dentists to offer a wide variety of implants, such as crowns, screws, dental bridges, dentures, and braces. Implant reliability and proper design are essential for patient comfort and usage. The selection of suitable materials, depending on the patient’s oral health and implant objectives, is the primary criteria for proper implant design.
  • 968
  • 17 Jan 2023
Topic Review
Deployment Optimization for UAV–IoT Networks
Unmanned aerial vehicles (UAVs) are widely used in Internet-of-Things (IoT) networks, especially in remote areas where communication infrastructure is unavailable, due to flexibility and low cost. However, the joint optimization of locations of UAVs and relay path selection can be very challenging, especially when the numbers of IoT devices and UAVs are very large.
  • 468
  • 28 Sep 2022
Topic Review
Derailleur Gears
Derailleur gears are a variable-ratio transmission system commonly used on bicycles, consisting of a chain, multiple sprockets of different sizes, and a mechanism to move the chain from one sprocket to another. Although referred to as gears in the bike world, these bicycle gears are technically sprockets since they drive or are driven by a chain, and are not driven by one another. Modern front and rear derailleurs typically consist of a moveable chain-guide that is operated remotely by a Bowden cable attached to a shifter mounted on the down tube, handlebar stem, or handlebar. When a rider operates the lever while pedalling, the change in cable tension moves the chain-guide from side to side, "derailing" the chain onto different sprockets. For more information about the choice of particular gear ratios and sprocket sizes, see Bicycle gearing.
  • 709
  • 16 Nov 2022
Topic Review
Deriving Vectorcardiography from 12-Lead ECG
Vectorcardiography (VCG) is a valuable diagnostic tool that complements the standard 12-lead ECG by offering additional spatiotemporal information to clinicians. However, due to the need for additional measurement hardware and too many electrodes in a clinical scenario if performed along with a standard 12-lead, there is a need to find methods to derive the VCG from the ECG.
  • 1.2K
  • 22 May 2023
Topic Review
Derringer
A derringer is a small handgun that is neither a revolver nor a semi/fully automatic pistol. It is not to be confused with mini-revolvers or pocket pistols, although some later derringers were manufactured with the pepperbox configuration. The modern derringer is often multi-barreled, and is generally the smallest usable handgun of any given caliber and barrel length due to the lack of a moving action, which takes up more space behind the barrel. It is frequently used by women because it is easily concealable in a purse or a stocking. The original Philadelphia Deringer was a muzzleloading caplock single-shot pistol introduced in 1825 by Henry Deringer. In total, approximately 15,000 Deringer pistols were manufactured. All were single barrel pistols with back-action percussion locks, typically .41 caliber with rifled bores, and walnut stocks. Barrel length varied from 1.5 to 6 in (38 to 152 mm), and the hardware was commonly a copper-nickel alloy known as "German silver". The term "derringer" (/ˈdɛrɪndʒər/) became a genericized misspelling during the reporting of the Lincoln assassination, which was committed with a concealed Philadelphia Deringer. Many copies of the original Philadelphia Deringer pistol were made by other gunmakers worldwide, and the name remained often misspelled; this misspelling soon became an alternative generic term for any pocket pistol, along with the generic phrase "palm pistol'", which Deringer's competitors invented and used in their advertising. With the advent of metallic cartridges, pistols produced in the modern form are still commonly called "derringers".
  • 5.3K
  • 01 Nov 2022
Topic Review
Desalination in China
In recent decades, the ever-growing demands for clean water in households and industries have urged researchers to take every possible step to deal with the global water crisis. Seawater desalination has turned out to be the most promising and efficient way to provide clean water. Owing to the advancement of synthetic chemistries and technologies, great success has been achieved in the desalination and utilization of seawater worldwide. China, with the world’s largest population, has pushed the development of desalination and multipurpose utilization of seawater further in respect of materials, technologies and services, etc. 
  • 1.1K
  • 30 Mar 2021
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