While broad economic indicators such as Gross Domestic Product may skew impressions of individual prosperity, data on disease and death reveal how a population is truly faring. Not only that, the ICD also captures factors influencing health, or external causes of mortality and morbidity, providing a holistic look at every aspect of life that can affect health. ICD codes draw an arc tangent to two unequal circles have enormous financial importance, since they are used to determine where best to invest increasingly scant resources.
In countries such as the USA, meanwhile, ICD codes are the foundation of health insurance billing, and thus critically tied up with health care finances. Crucially, in a world of 7. Fifty years ago, it would be unlikely that a disease such as schizophrenia would be diagnosed similarly in Japan, Kenya and Brazil. Standardization is the key that unlocks global health data analysis.
Gender incongruence, meanwhile, has also been moved out of mental disorders in the ICD, into sexual health conditions. The rationale being that while evidence is now clear that it is not a mental disorder, and indeed classifying it in this can cause enormous stigma for people who are transgender, there remain significant health care needs that can best be met if the condition is coded under the ICD. For mental health conditions, ICD codes are especially important since the ICD is a diagnostic tool, and thus, these are the conditions that often garner much of the interest in the ICD.
These include gaming disorder, which evidence shows is enough of a health problem that it requires tracking through the ICD. A significant change in the mental disorders section of ICD is the attempt of statisticians to simplify the codes as much as possible to allow for coding of mental health conditions by primary health care providers rather than by mental health specialists.
The history of the ICD traces back to England in the 16th century. Every week, the London Bills of Mortality would announce deaths from distinctly medieval causes: scurvy, leprosy, and the big killer — plague.
Around the same time French statistician Jacques Bertillon introduced the Bertillon Classification of Causes of Death, which was adopted by several countries. This allowed for the first time the collection of both morbidity and mortality data to map both disease trends and causes of death.
The data captured through ICD codes is of huge importance for countries. A country in which people live in crowded, inadequate housing with no clean water are inevitably likely to have a higher incidence of diarrhoeal disease.
These statistics are critical in tracking progress towards key targets such as the Sustainable Development Goals.
ICD Classifying disease to map the way we live and die. Coding disease and death. Ready for the 21st century. Over a decade in the making, this version is a vast improvement on ICDTo browse Academia. Skip to main content. Log In Sign Up. Silica Sand as used by Foundries is desired for its thermal resistance and availability. In Queensland Australia it falls under the minerals act as it is processed and sold for its chemical properties.
Whilst Silica Sand is abundant throughout Australia the technical requirements of Foundries allow only a few deposits to be mined and processed for their use.
When referring to Silica Sand for Foundry use we define it as the mineral quartz; its sizing, chemical purity, shape and physical durability will be discussed along with the thermal properties.
The Surface Area of the Sand Grains must be low as the use of Resin has a major impact on a Foundries competitiveness and profitability.
With correct sizing and sphericity a maximum Bulk density can be achieved, a high grade Silica Sand will have a dry bulk density of approximately 1. There are formulas and tables for the calculation of sphericity however if we imagine perfect spheres and the way they would pack given the correct vibration then we can picture the following scene: Perfect spherical grains of sand would in theory pack the closest and give a theoretical permeability of zero.
That is gas would not pass through it. It was from this theory that sand size distribution and shape have been decided upon. Sand is rarely round and spherical and the terms: well rounded, sub- angular to rounded and angular have been adopted. Fortunately a certain degree of permeability is necessary and is why we can use Silica that is sub-angular to rounded, refer photo 2. Ideally the sand grains should be spread across four sieve sizes in a Bell type distribution.
The Older Silica Sand deposits are subjected to a greater degree of weathering hence a rounder grain evolves. This explains photo 2 where this material was laid down a mere 12, Years ago! The wet product can then be blended and literally cut off at a selected grain size effectively between microns, 0. Wet and dry screens, select silica Sand sizing hydraulic classification such as hydro cyclones, settling tanks and high velocity T cell classifiers.
The washing process can involve as many as three to four cycles to ensure that the sand has an exceptionally low turbidity, free from clay and fines, low in unwanted salts and an acceptable pH value. A Table displays the way in which this is calculated and a simple spreadsheet can be devised and used.
Sieves of known size are assembled and placed in a vibratory jig. The grains fall through square mesh sizes that are placed coarse on top usually 0.
The sand that is retained on each sieve is weighed and tabulated, that weight is multiplied by a factor dependent upon the sieve size it was recorded against and an AFS GFN Number is calculated. It is resistant to molten Steel and Iron it has high hardness and is compatible with all types of Foundry Binder systems. Silica has a high fusion point above degrees Celsius. These elements can drastically lower the sintering point of Silica the alkaline nature of the elements and their oxides listed above can drop a Foundry processes can be divided into two types:- ferrous foundries and non-ferrous foundries.
Foundry processes involve making the mould and the core, melting and pouring the metal into the mould, and finally removing the mould and core and finishing the product. Although different processes differ in the number of steps required to make the final product. Metal casting process starts with creation of mold. Metal that can be molted will be poured into this mould and cooled. The form of metal being used and shape of final product required would decide the material, which will be used to make the cast.
A commonly used molding material is sand. Investment materials, metals, etc. Different types of metals are used for melting different metals. Various Furnaces types are cupolas, electric arc, induction, hearth or reverberatory and crucible. Due to the different nature of metals, varying inputs are required and different toxic wastes are released from each type.
After the metal has been melted, it is poured into the cast already made previously and made to cool and set. Silica sand, moisture, oils and green sand are mixed together to form a mould cavity.
Metal is then poured in this cavity. When the metal is cooled, it is easily separated from the mould. This type of sand should b capable of handling high temperatures and pressure, allow gases to escape, have a constantly small grain size and be non-reactive with metals. The wastes produced by foundries depend on the type of metal, foundry types. They contain metal, semi-volatile and volatile organic compounds. Emission control systems can be installed to capture these gases.
Liquid wastes in foundry results from water used to chill metal. A water treatment plant can be installed for water waste. Solid wastes come from slag, sand, spent refractories, and emissions control dust.
For this various process like sand reclamation, attrition sand reclamation, dry sand reclamation, wet sand reclamation, etc is used. Sand may also be recycled for outside processes.
Slag and emission are also a waste produced by a foundry. These can be fed back to furnace to recover any metal, which can possibly be recovered. In depth analysis of industry process, recycling, and environmental issues of the cast metals industry. Know More. Latest manufacturing technology research in production, manufacturing engineering and management.
All about industrial applications of metal casting technologies in Automobile, Industrial Machinery.[HINDI] CASTING - CLASSIFICATION OF CASTING - MOULD - PATTERN - CORE - MUST WATCH
Other special foundry processes are thermal galvanization and electro less nickel plating. Enviornmental Issues In depth analysis of industry process, recycling, and environmental issues of the cast metals industry.
New Technology Research Latest manufacturing technology research in production, manufacturing engineering and management. Casting Applications All about industrial applications of metal casting technologies in Automobile, Industrial Machinery.For example:. The translation faithfully reproduces all of the content of the source database, even where this contravenes OBO guidelines.
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Semiconductor fabrication plant
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Although these sands are clean prior to use, after casting they may contain Ferrous iron and steel industries account for approximately 95 percent of foundry sand used for castings. The automotive industry and its parts suppliers are the major generators of foundry sand. The most common casting process used in the foundry industry is the sand cast system. Virtually all sand cast molds for ferrous castings are of the green sand type.
Green sand consists of high-quality silica sand, about 10 percent bentonite clay as the binder2 to 5 percent water and about 5 percent sea coal a carbonaceous mold additive to improve casting finish. The type of metal being cast determines which additives and what gradation of sand is used. The green sand used in the process constitutes upwards of 90 percent of the molding materials used. In addition to green sand molds, chemically bonded sand cast systems are also used.
Foundry sand makes up about 97 percent of this mixture. Chemically bonded systems are most often used for "cores" used to produce cavities that are not practical to produce by normal molding operations and for molds for nonferrous castings. The annual generation of foundry waste including dust and spent foundry sand in the United States is believed to range from 9 to Additional information on the production and use of spent foundry sand in construction materials applications can be obtained from:.
In typical foundry processes, sand from collapsed molds or cores can be reclaimed and reused. A simplified diagram depicting the flow of sand in a typical green sand molding system is presented in Figure Some new sand and binder is typically added to maintain the quality of the casting and to make up for sand lost during normal operations. Little information is available regarding the amount of foundry sand that is used for purposes other than in-plant reclamation, but spent foundry sand has been used as a fine aggregate substitute in construction applications and as kiln feed in the manufacture of Portland cement.
Most of the spent foundry sand from green sand operations is landfilled, sometimes being used as a supplemental cover material at landfill sites. Foundry sand can be obtained directly from foundries, most of which are located in midwestern states, including Illinois, Wisconsin, Michigan, Ohio, and Pennsylvania. Foundry sand, prior to use, is a uniformly graded material. The spent material, however, often contains metal from the casting and oversized mold and core material containing partially degraded binder.
Spent foundry sand may also contain some leachable contaminants, including heavy metals and phenols that are absorbed by the sand during the molding process and casting operations. Phenols are formed through high-temperature thermal decomposition and rearrangement of organic binders during the metal pouring process.
Foundry sand has been used as a substitute for fine aggregate in asphalt paving mixes. It has also been used as a fine aggregate substitute in flowable or controlled density fill applications. Prior to use, spent foundry sand requires crushing or screening to reduce or separate oversized materials that may be present. Stockpiles of sufficient size typically need to be accumulated so that a consistent and uniform product can be produced i.
Since only small quantities of spent foundry sand are generated at small foundries, it will generally be necessary for these operators to transport their spent sand to a central storage area that receives sand from a group of plants before transferring it to an end user. The grain size distribution of spent foundry sand is very uniform, with approximately 85 to 95 percent of the material between 0. Five to 12 percent of foundry sand can be expected to be smaller than 0.
The particle shape is typically subangular to rounded. Waste foundry sand gradations have been found to be too fine to satisfy some specifications for fine aggregate. Spend foundry sand has low absorption and is nonplastic.In the microelectronics industry, a semiconductor fabrication plant commonly called a fab ; sometimes foundry is a factory where devices such as integrated circuits are manufactured.
A business that operates a semiconductor fab for the purpose of fabricating the designs of other companies, such as fabless semiconductor companiesis known as a foundry. If a foundry does not also produce its own designs, it is known as a pure-play semiconductor foundry. If a foundry produces its own designs, it is known as an integrated device manufacturer IDM.
Fabs require many expensive devices to function. Estimates put the cost of building a new fab over one billion U. The central part of a fab is the clean rooman area where the environment is controlled to eliminate all dust, since even a single speck can ruin a microcircuit, which has nanoscale features much smaller than dust. The clean room must also be damped against vibration, to enable nanometer-scale alignment of machines, and must be kept within narrow bands of temperature and humidity.
Controlling temperature and humidity is critical for minimizing static electricity. Corona discharge sources can also be used to reduce static electricity. Often, a fab will be constructed in the following manner: from top to bottom : the roof, which may contain air handling equipment that draws, purifies and cools outside air, an air plenum for distributing the air to several floor-mounted fan filter unitswhich are also part of the cleanroom's ceiling, the cleanroom itself, which may or may not have more than one floor the clean subfab that contains chemical delivery, purification, and destruction systems, and the ground floor, that contains electrical equipment.
The clean room contains the steppers for photolithographyin addition to etchingcleaning, doping and dicing machines. All these devices are extremely precise and thus extremely expensive. A typical fab will have several hundred equipment items. Typically an advance in chip-making technology requires a completely new fab to be built.
SIC to NAIC Conversion Charts
In the past, the equipment to outfit a fab was not very expensive and there were a huge number of smaller fabs producing chips in small quantities. However, the cost of the most up-to-date equipment has since grown to the point where a new fab can cost several billion dollars. Another side effect of the cost has been the challenge to make use of older fabs.
For many companies these older fabs are useful for producing designs for unique markets, such as embedded processorsflash memoryand microcontrollers. However, for companies with more limited product lines, it's often best to either rent out the fab, or close it entirely. This is due to the tendency of the cost of upgrading an existing fab to produce devices requiring newer technology to exceed the cost of a completely new fab.
There has been a trend to produce ever larger wafersso each process step is being performed on more and more chips at once. The goal is to spread production costs chemicals, fab time over a larger number of saleable chips.
It is impossible or at least impracticable to retrofit machinery to handle larger wafers. This is not to say that foundries using smaller wafers are necessarily obsolete; older foundries can be cheaper to operate, have higher yields for simple chips and still be productive. This is often referred to as the " lights-out fab " concept. An important goal of this initiative is to enable fabs to produce greater quantities of smaller chips as a response to shorter lifecycles seen in consumer electronics.
The logic is that such a fab can produce smaller lots more easily and can efficiently switch its production to supply chips for a variety of new electronic devices. Another important goal is to reduce the waiting time between processing steps. From Wikipedia, the free encyclopedia. It has been suggested that this article be merged with Semiconductor device fabrication.
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