Powdered, Specification Requirements

The determination of the specific surface area of a powder by air permeability methods essentially involves the measurement of the pressure drop across a bed of the powder under carefully controlled flow conditions. The data obtained are substituted in the Kozeny-Carman equation to estimate the specific surface area. Permeability methods have certain advantages, one of them being that the equipment used for carrying out the measurements is cheap and robust. Another advantage is that sample problems are minimized because a large sample of powder is required to be used for analysis. 

Advances in quality control requirements for rubber compounds have demanded that special care is exercised in the weighing of the various fillers and critical small volume powders necessary for the formulation. Ingredient weighing systems are available which can be tailored to the specific requirements of individual factories. Additional components can include conveyors, bagging units and pneumatic conveyance systems. 

Materials purchased for the purpose of mixing with other materials in the preparation of pharmaceutical products are called raw materials. Pharmaceutical companies often purchase solid raw materials as powders in large drums. Quality assurance laboratories require samples of the material in the drums for the purpose of performing quality tests to see if the raw materials meet the specifications required for the company s products. 

Borates, through their ability to act as glass network formers, can act as excellent char formers and drip suppressants in fire retardant applications. In many cases this involves processing into polymeric materials, leading to specific requirements for thermal stability and particle size. Most common borate materials, however, exhibit relatively low dehydration temperatures and may be unsuitable for use in many polymer systems. Zinc borates are often used because they have unusually high dehydration onset temperatures and can be produced as small particle size powders. 

Special protection comprises all protection techniques such as powder filling, static pressurization and encapsulation (by plastics materials). At that time, these techniques started their career in the field of explosion protection and advanced to autonomous types of protection described by IEC or European Standards individually. VDE 0170/0171/1969-01 does not contain any specific requirements for these techniques. It has been the decision of the certifying body that an s -apparatus will operate at the same level of safety compared with other well-defined types of protection, e.g. flameproof enclosure d ... 

The intention of this paper is to describe some of the more unusual safety design requirements. In order to better understand these requirements, a brief history of the type of process utilized in the manufacture of BALL POWDER is presented. Next those safety advantages internal to the process are summarized. Specific requirements in the areas of grain formation, nitroglycerine manufacture and transfer, and continuous drying are discussed. Finally, the basic fire protection system utilized is described. 

Hydroxyapetite (Caio(P04)g(OH)2) is the major constituent of human bone and teeth. The strength of HA in almost all of its applications is largely determined by its specific surface area, and so a nanocrystalhne HA powder is required. 

The powder obtained with the MHQ technique, which has to be maintained below 140 K to prevent further reaction, is more difficult to handle than that produced by the RFQ technique because of its finer structure. To apply the spectrocopies listed above to such a powder, one often has to construct specific adaptations to sample holders and/or sample compartments, in particular, to get the powder where required, without warming during handling and operation. 

For example, a company which experienced a customer complaint involving a large glass fragment in an aseptically filled powder vial introduced procedural preventive measures but concluded that the issue required automated vision inspection equipment. Once the corrective equipment was identified, a validation master plan detailed the key qualification elements for hardware, software, defect detection system, infeed/outfeed links, but also the specification requirements of the component and component quality, e.g ... 

Adhesive price is dependent on development costs and volume requirements. Adhesives that have been specifically designed to be resistant to adverse environments are more expensive than general-purpose adhesives. Adhesive prices range from pennies a pound for inorganic and animal-based systems to hundreds of dollars per pound for certain heat-resistant synthetic adhesives. Adhesives in film or powder form require more processing than liquid or paste types and are more expensive. 

The extent to which the characterization process is taken depends on the application. In the case of traditional ceramics, which do not have to meet exacting property requirements, a fairly straightforward observation, with a microscope, of the size, size distribution, and shape of the powdCTs may be sufficient. For advanced ceramics, however, detailed knowledge of the powder characteristics is required for adequate control of the microstructure and properties of the fabricated material. Commercial powders are used in most applications. Normally, the manufacturer has carried out most of the characterization experiments and provides the user with the results, generally referred to as powder specifications. The manufacturer s specifications combined with a straightforward observation of the powder with a microscope are sufficient for many applications. 

The association of polypyrrole with other materials in order to prepare hybrid materials in which the properties of both components are associated with possible synergic effects is the main method of meeting the specific requirements of physical properties for each type of application. Processes connected with poly-pyrrole are developed in order to obtain films, powders, solutions, gels and blends. As a result of progress in the processing of polypyrrole, applications with very large markets can now be considered. 

The quality of dry powder is the single most important factor that is considerably affected by the operating conditions of the process. Powder character and quality are usually determined by further processing or by consumer requirements. To meet the required bulk density of the dry powder, it is necessary to know how the particle size and size distribution are affected by various parameters. General information about the selection of spray dryer design to meet powder specifications can be found in Reffi. [11,23,24], and, for the particular case of food drying, in Ref. [17]. 

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