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Topic Review
Eye Chart
An eye chart, or optotype, is a chart used to measure visual acuity. Eye charts are often used by health care professionals, such as optometrists, physicians or nurses, to screen persons for vision impairment. Ophthalmologists, physicians who specialize in the eye, also use eye charts to monitor the visual acuity of their patients in response to various therapies such as medications or surgery. The chart is placed at a standardized distance away from the person whose vision is being tested. The person then attempts to identify the symbols on the chart, starting with the larger symbols and continuing with progressively smaller symbols until the person cannot identify the symbols. The smallest symbols that can be reliably identified is considered the person's visual acuity. The Snellen chart is the most widely used. Alternative types of eye charts include the logMAR chart, Landolt C, E chart, Lea test, Golovin–Sivtsev table, the Rosenbaum chart, and the Jaeger chart. As previously mentioned, eye charts measure visual acuity. Eye charts do not provide doctors with information on eye diseases such as glaucoma, problems with the retina, or loss of peripheral vision.
  • 563
  • 18 Nov 2022
Topic Review
Cartridge (Respirator)
}} A respirator cartridge or canister is a container that cleans pollution from air. Employees working in a polluted atmosphere use respirators for health preservation. If the air in the workplace is polluted with noxious gases, but contains a lot of oxygen they often use air-purifying respirators (APR). These respirators provide employees breathable air by removing pollution from ambient air using canisters or cartridges. There are cartridges of different types, and they must be chosen correctly and replaced in a timely manner.
  • 534
  • 16 Nov 2022
Topic Review
Quality Control in the Resistance Spot Welding Process
Resistance spot welding (RSW) is a process characterized by its high speed and adaptability for automation that renders it suitable for mass production. 
  • 866
  • 11 Nov 2022
Topic Review
Digital Versus Film Photography
The merits of digital versus film photography were considered by photographers and filmmakers in the early 21st century after consumer digital cameras became widely available. Digital photography and digital cinematography have both advantages and disadvantages relative to still film and motion picture film photography. In the 21st century, photography came to be predominantly digital, but traditional photochemical methods continue to serve many users and applications.
  • 442
  • 10 Nov 2022
Topic Review
DAISY Digital Talking Book
DAISY (Digital Accessible Information SYstem) is a technical standard for digital audiobooks, periodicals and computerized text. DAISY is designed to be a complete audio substitute for print material and is specifically designed for use by people with "print disabilities", including blindness, impaired vision, and dyslexia. Based on the MP3 and XML formats, the DAISY format has advanced features in addition to those of a traditional audio book. Users can search, place bookmarks, precisely navigate line by line, and regulate the speaking speed without distortion. DAISY also provides aurally accessible tables, references and additional information. As a result, DAISY allows visually impaired listeners to navigate something as complex as an encyclopedia or textbook, otherwise impossible using conventional audio recordings. DAISY multimedia can be a book, magazine, newspaper, journal, computerized text or a synchronized presentation of text and audio. It provides up to six embedded "navigation levels" for content, including embedded objects such as images, graphics, and MathML. In the DAISY standard, navigation is enabled within a sequential and hierarchical structure consisting of (marked-up) text synchronized with audio. DAISY 2 was based on XHTML and SMIL. DAISY 3 is a newer technology, also based on XML, and is standardized as ANSI/NISO Z39.86-2005. The DAISY Consortium was founded in 1996 and consists of international organizations committed to developing equitable access to information for people who have a print disability. The consortium was selected by the National Information Standards Organization (NISO) as the official maintenance agency for the DAISY/NISO Standard.
  • 873
  • 09 Nov 2022
Topic Review
Anaesthetic Vaporizer
An anaesthetic vaporizer is a device generally attached to an anaesthetic machine which delivers a given concentration of a volatile anaesthetic agent. It works by controlling the vaporisation of anaesthetic agents from liquid, and then accurately controlling the concentration in which these are added to the fresh gas flow. The design of these devices takes account of varying: ambient temperature, fresh gas flow, and agent vapour pressure.
  • 433
  • 09 Nov 2022
Topic Review
Guard Rail
Guard rail, guardrails — or railings around properties and more generally outside of North America in some uses overlaps the industrial term "guide rail". They are a boundary feature and may be a means to prevent or deter access to dangerous or off-limits areas while allowing light and visibility in a greater way than a fence. Common shapes are flat, rounded edge, and tubular in horizontal railings, whereas tetraform spear-headed or ball-finialled are most common in vertical railings around homes. Park and garden railings commonly in metalworking feature swirls, leaves, plate metal areas and/or motifs particularly on and beside gates. High security railings (particularly if in flat metal then a type of palisade) may instead feature jagged points and most metals are well-suited to anti-climb paint. A handrail is less restrictive on its own than a guard rail and provides support.
  • 934
  • 07 Nov 2022
Topic Review
Abdominal Exercise
Abdominal exercises are type of strength exercise those that affect the abdominal muscles (colloquially known as the stomach muscles or "abs").
  • 357
  • 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
Properties of HVOF-PVD Duplex Coatings
The morphology (surface and cross-section) of the high-velocity oxygen–fuel coupled physical vapor deposition (HVOF-PVD)  duplex coating and its mechanical (stress and load-bearing capacity), tribological (wear and lubrication), and corrosion (chemical and electrochemical) behavior are described and discussed for surface protective concern. The duplex coating involves a combination of a thick, hard HVOF bottom layer and a thin, hard yet tough PVD top layer. The hardness and modulus of the HVOF coating are between those of the soft substrate and the hard PVD coating, which thereafter provides a smooth transition and effective support between them. As a result, the HVOF interlayer can eliminate the plastic deformation of the substrate due to stress concentration under heavy load, effectively avoiding the “eggshell effect”. As expected, the duplex coating system would provide excellent load-bearing capacity. In terms of tribology, the wear resistance of the HVOF-PVD duplex coating is significantly improved compared to that of PVD monolayer coating. 
  • 541
  • 03 Nov 2022
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