Subject:
All Disciplines Arts & Humanities Biology & Life Sciences Business & Economics Chemistry & Materials Science Computer Science & Mathematics Engineering Environmental & Earth Sciences Medicine & Pharmacology Physical Sciences Public Health & Healthcare Social Sciences
Sort:
Hottest Latest Alphabetical (A-Z) Alphabetical (Z-A)
Type:
All Topic Review Biography
Topic Review
Quartz Crystal Microbalances' Electrode Shape and Mass Sensitivity
A quartz crystal microbalance (QCM) is a typical acoustic transducer that undergoes a frequency shift due to changes in the mass of its surface. Its high sensitivity, robustness, small size design, and digital output have led to its widespread development for application in the fields of chemistry, physics, biology, medicine, and surface science. Mass sensitivity is one of the vital parameters and forms the basis for quantitative analysis using QCMs.
  • 1.0K
  • 13 Jul 2022
Topic Review
Chemical and Physical Properties of Solid Salt Fluxes
Solid salt fluxes are inorganic compounds that are added during the treatment of molten aluminum to improve the final quality. An understanding of the chemical composition of the flux is essential for the assessment of the physical and chemical behavior of the flux. The chemical composition of the flux can be tailored to adjust properties such as density, viscosity, reactivity, and wettability. Such properties, in turn, will impart different functions to the flux. 
  • 1.0K
  • 05 May 2023
Topic Review
Conventional PCI
Conventional PCI, often shortened to PCI, is a local computer bus for attaching hardware devices in a computer. PCI is an abbreviation for Peripheral Component Interconnect and is part of the PCI Local Bus standard. The PCI bus supports the functions found on a processor bus but in a standardized format that is independent of any particular processor's native bus. Devices connected to the PCI bus appear to a bus master to be connected directly to its own bus and are assigned addresses in the processor's address space. It is a parallel bus, synchronous to a single bus clock. Attached devices can take either the form of an integrated circuit fitted onto the motherboard itself (called a planar device in the PCI specification) or an expansion card that fits into a slot. The PCI Local Bus was first implemented in IBM PC compatibles, where it displaced the combination of several slow ISA slots and one fast VESA Local Bus slot as the bus configuration. It has subsequently been adopted for other computer types. Typical PCI cards used in PCs include: network cards, sound cards, modems, extra ports such as USB or serial, TV tuner cards and disk controllers. PCI video cards replaced ISA and VESA cards until growing bandwidth requirements outgrew the capabilities of PCI. The preferred interface for video cards then became AGP, itself a superset of PCI, before giving way to PCI Express. The first version of PCI found in retail desktop computers was a 32-bit bus using a 33 MHz bus clock and 5 V signalling, although the PCI 1.0 standard provided for a 64-bit variant as well. These have one locating notch in the card. Version 2.0 of the PCI standard introduced 3.3 V slots, physically distinguished by a flipped physical connector to prevent accidental insertion of 5 V cards. Universal cards, which can operate on either voltage, have two notches. Version 2.1 of the PCI standard introduced optional 66 MHz operation. A server-oriented variant of PCI, called PCI-X (PCI Extended) operated at frequencies up to 133 MHz for PCI-X 1.0 and up to 533 MHz for PCI-X 2.0. An internal connector for laptop cards, called Mini PCI, was introduced in version 2.2 of the PCI specification. The PCI bus was also adopted for an external laptop connector standard – the CardBus. The first PCI specification was developed by Intel, but subsequent development of the standard became the responsibility of the PCI Special Interest Group (PCI-SIG). Conventional PCI and PCI-X are sometimes called Parallel PCI in order to distinguish them technologically from their more recent successor PCI Express, which adopted a serial, lane-based architecture. PCI's heyday in the desktop computer market was approximately 1995–2005. PCI and PCI-X have become obsolete for most purposes; however, they are still common on modern desktops for the purposes of backwards compatibility and the low relative cost to produce. Many kinds of devices previously available on PCI expansion cards are now commonly integrated onto motherboards or available in USB and PCI Express versions.
  • 1.0K
  • 27 Oct 2022
Topic Review
Efficient and Effective Rankings
In the simple words of Peter Drucker, efficiency is doing things right while effectiveness is doing the right things. Efficient and Effective Rankings are ranking classifications for Decision-Making Units (DMUs) based on a combination of the efficiency score (obtained by parametric or non-parametric Data Envelopment Analysis frontier estimations) with a multiple effectiveness measure (often obtained using a Multicriteria Decision Analysis). This study aims at providing a non-compensatory ranking classification combining Conditional Frontier Analysis with the PROMETHEE II methodology for the multidimensional efficiency and effectiveness analysis of Police. The results on Pernambuco (Brazil) Police departments offer interesting perspectives for public administrations concerning prioritizations of units based on the mitigation of resources and strategic objectives.
  • 1.0K
  • 30 Apr 2021
Topic Review
Mac Transition to Apple Silicon
The Mac transition to Apple Silicon is the planned two-year process of introducing ARM64-based Apple silicon to, and deprecating Intel's x86-64 from, Apple's Macintosh line of computers. CEO Tim Cook announced the plan in his WWDC keynote address on June 22, 2020. The transition is the third time Apple has migrated Macintosh to a new instruction set architecture (ISA). The first was the switch from the Mac's original Motorola 68000 series architecture to the new PowerPC platform in 1994, and the second was the transition from PowerPC to Intel x86, which was formally announced in June 2005. Apple first utilized the ARM architecture in 1993 in its Newton personal digital assistant, and since then has extensively deployed it throughout other product lines including iPhone, iPad, iPod, and Apple Watch. Apple has designed its own custom ARM chips since 2009.
  • 1.0K
  • 02 Nov 2022
Topic Review
HP Series 80
The Hewlett-Packard series 80 of small scientific desktop computers was introduced in 1980, beginning with the popular HP-85 targeted at engineering and control applications. They provided the capability of the HP 9800 series desktop computers with an integrated monitor in a smaller package including storage and printer, at half the price.
  • 1.0K
  • 30 Nov 2022
Topic Review
Low-Cost Thermal Cameras
Thermal imaging is a promising technology in the medical field, in which infrared (IR) sensors can be used in e-health applications. However, in order to make this technology more accessible, the suitability of low-cost devices for such applications has been evaluated. Low-cost sensors present reduced capabilities compared to more expensive high-end devices. Therefore, their characterization is of outmost interest, which is performed in terms of the following parameters: non-uniformity (NU) effects and correction as well as their dependence on room temperature, noise-equivalent temperature difference (NETD), and response curve stability with temperature. In this work, a good performance is shown for the selected low-cost sensor, especially when used in temperature-controlled environments. Thus, the suitability of such sensors for medical applications is confirmed, proving its efficiency for the particular application we are focused on, this is, the assessment of diabetic foot ulcers.
  • 1.0K
  • 29 Oct 2020
Topic Review
Semiconductor Device
Semiconductor devices are electronic components that exploit the electronic properties of semiconductor materials, principally silicon, germanium, and gallium arsenide, as well as organic semiconductors. Semiconductor devices have replaced thermionic devices (vacuum tubes) in most applications. They use electronic conduction in the solid state as opposed to the gaseous state or thermionic emission in a high vacuum. Semiconductor devices are manufactured both as single discrete devices and as integrated circuits (ICs), which consist of a number—from a few (as low as two) to billions—of devices manufactured and interconnected on a single semiconductor substrate, or wafer. Semiconductor materials are useful because their behavior can be easily manipulated by the addition of impurities, known as doping. Semiconductor conductivity can be controlled by the introduction of an electric or magnetic field, by exposure to light or heat, or by the mechanical deformation of a doped monocrystalline grid; thus, semiconductors can make excellent sensors. Current conduction in a semiconductor occurs via mobile or "free" electrons and holes, collectively known as charge carriers. Doping a semiconductor such as silicon with a small proportion of an atomic impurity, such as phosphorus or boron, greatly increases the number of free electrons or holes within the semiconductor. When a doped semiconductor contains excess holes it is called "p-type", and when it contains excess free electrons it is known as "n-type", where p (positive for holes) or n (negative for electrons) is the sign of the charge of the majority mobile charge carriers. The semiconductor material used in devices is doped under highly controlled conditions in a fabrication facility, or fab, to control precisely the location and concentration of p- and n-type dopants. The junctions which form where n-type and p-type semiconductors join together are called p–n junctions. Semiconductor devices made per year have been growing by 9.1% on average since 1978 and shipments in 2018 are predicted for the first time to exceed 1 trillion, meaning well over 7 trillion has been made to date, in just in the decade prior.
  • 1.0K
  • 26 Oct 2022
Topic Review
Li-Ion Battery Technologies
Lithium-ion battery is a rechargeable battery, which mainly relies on the movement of lithium ions between the positive and negative electrodes to work. Lithium-ion batteries use an intercalated lithium compound as an electrode material. Currently, the main common cathode materials used as lithium ion batteries are: lithium cobalt oxide, lithium manganate, lithium nickelate and lithium iron phosphate.
  • 1.0K
  • 15 Nov 2021
Topic Review
Wireless Sensor Network in Environment Monitoring
The Internet of Things (IoT) technology and its applications are turning real-world things into smart objects, integrating everything under a common infrastructure to manage performance through a software application and offering upgrades with integrated web servers in a timely manner. Quality of life, the green economy, and pollution management in society require comprehensive environmental monitoring systems with easy-to-use features and maintenance.
  • 1.0K
  • 11 Aug 2022
  • Page
  • of
  • 650
Featured Entry Collections
>>

Featured Books

>>
Encyclopedia of Social Sciences
Encyclopedia of COVID-19
Encyclopedia of Fungi
Encyclopedia of Digital Society, Industry 5.0 and Smart City
ScholarVision Creations
Feedback