Natural quality specifications

There are several systems that define the quality and uniformity of natural mbber. One system of grading natural mbber is based on form and visual observation of color and cleanliness. This is known as the International Natural Rubber Specification. The principal types and grades are as follows. There are five other types of mbber classified by this system and many other grades not Hsted here. 

The reliability of any environmental analytical data depends upon the reliability of sample quality. To generalize from analytical results on a small portion of material to a larger population requires careful planning and execution if bias is to be avoided. This article considers the general problems involved in sampling heterogeneous bulk populations such as soil, air, and natural waters specific details for particular types of materials are not included. These problems include the heterogeneity of most environmental materials the costs in time, manpower, and effort required for collection of real samples and the need to avoid contamination or decomposition of samples after collection. 

Industrial systems which can be described entirely by equations are rare. Although, as in the case of material balances, the constraints imposed by Nature often are strict, those imposed by Man more usually allow some leeway. Product specifications fix the minimum quality permitted, but no one objects if the standards are exceeded. The amount of available raw material limits the quantity which can be produced, but usually no harm is done if some raw material is left unused. Quality specifications and material availabilities are described mathematically by inequalities rather than equations. Another type of inequality arises in industrial problems which is so obvious that it is easy to overlook. This is the fact that no material can be consumed in negative amounts. Thus, a set of non-negative values satisfying a set of constraints is called a feasible solution to the constraints. 

Uncertainty and disturbances can be described in terms of mathematical constraints defining a finite set of hounded regions for the allowable values of the uncertain parameters of the model and the parameters defining the disturbances. If uncertainty or disturbances were unbounded, it would not make sense to try to ensure satisfaction of performance requirements for all possible plant parameters and disturbances. If the uncertainty cannot be related mathematically to model parameters, the model cannot adequately predict the effect of uncertainty on performance. The simplest form of description arises when the model is developed so that the uncertainty and disturbances can be mapped to independent, bounded variations on model parameters. This last stage is not essential to the method, but it does fit many process engineering problems and allows particularly efficient optimization methods to be deployed. Some parameter variations are naturally bounded e.g.. feed properties and measurement errors should be bounded by the quality specification of the supplier. Other parameter variations require a mixture of judgment and experiment to define, e.g., kinetic parameters. 

Hazard identification explores potential concerns about a chemical. It involves an evaluation of the nature, quality, and relevance of scientific data on the specific chemical, the characteristics and relevance of the experimental routes of exposure, and the nature and significance of the observed effects. In this step, scientific studies are reviewed to determine if exposure to an agent could cause increased incidence of adverse health effects (noncancer or cancer effects) in humans, and to identify which effects the chemical can cause. 

Hall, K.R., Yarborough, L, Lindsay, R., Kilmer, J., Fling, W., Calculation of Gross Heating Value for a Saturated Gas from Compositional Analysis, International Congress of Gas Quality—Specification and Measurement of Physical and Chemical Propeties of Natural Gas, Gronigen, The Netherlands (1986), April. 

Natural gas produced at the well head has to be treated in several processing steps especially dehydration and hydrocarbon dew pointing to meet the required pipeline and quality specifications. Water and higher hydrocarbon have to be removed in order to avoid the build-up of gas hydrates. The commonly used state-of-the-art processes, such as absorption and cryogenic condensation, have shortcomings with respect to environmental aspects, energy consumption, weight and space requirements. A reliable and proven membrane process could offer a serious alternative in comparison to established techniques. 

When any sample has been taken, the container must be properly labelled to indicate the nature of the material, the quantity the sample represents, and its source, for example the batch number. It is then submitted to the quality control or analytical laboratory for testing. These tests will ensure that the material, whether raw material or product, meets the standard laid down in the quality specifications for its particular use. Common tests on solid materials Include those for colour, water or solvent content, melting point (for organic chemicals which have relatively low melting points), dirt, appearance, bulk density, particle size, and assay (the percentage by weight of the active ingredient). 

For each of these intensification challenges, the objective to be reached (volume reduction, reduced size/capadty ratio, etc.), and also the constraints (fixed productivity, fixed performance, quality specifications, etc.) can be identified and quantified with respect to technical and economic data. Unfortunately, the means to tackle these issues are much more complex to define since they can be of very different natures operating conditions (temperature, pressure, concentrations, etc.), physical or chemical parameters (solvents, catalysts, etc.), equipment (heat exchangers, mixers, columns, etc.), process parameters (reflux ratio, feed strategy of semi-batch reactors, separate unit operations or multi-functional reactors, separator types, etc.). In... 

The measurement of hydrogen sulfide in natural gas is important, due to the gas quality specifications, the corrosive nature of H2S on pipeline materials, and the effects of H2S on utilization equipment. 

Obtaining high-quality nanocry stalline samples is the most important task faced by experimentalists working in tire field of nanoscience. In tire ideal sample, every cluster is crystalline, witli a specific size and shape, and all clusters are identical. Wlrile such unifonnity can be expected from a molecular sample, nanocrystal samples rarely attain tliis level of perfection more typically, tliey consist of a collection of clusters witli a distribution of sizes, shapes and stmctures. In order to evaluate size-dependent properties quantitatively, it is important tliat tire variations between different clusters in a nanocrystal sample be minimized, or, at tire very least, tliat tire range and nature of tire variations be well understood. 

Compared with XPS and AES, the higher surface specificity of SSIMS (1-2 mono-layers compared with 2-8 monolayers) can be useful for more precise determination of the chemistry of an outer surface. Although from details of the 01s spectrum, XPS could give the information that OH and oxide were present on a surface, and from the Cls spectrum that hydrocarbons and carbides were present, only SSIMS could be used to identify the particular hydroxide or hydrocarbons. In the growth of oxide films for different purposes (e.g. passivation or anodization), such information is valuable, because it provides a guide to the quality of the film and the nature of the growth process. 

The requirements of ISO 9001 do not apply solely to one department. As everyone in some way contributes to the quality of the products and services provided by the supplier, everyone shares the responsibility for the quality of these products and services. Every manager within an organization makes a unique contribution towards the organization s purpose and mission. The achievement of quality, however, is everyone s job but only in so far as each person is responsible for the quality of what they do. You cannot hold each person accountable for ensuring that the requirements of ISO 9001 are implemented and maintained, as the requirements apply to the organization as a whole and not to any specific individual. It is a trait of human nature that there has to be a leader for an organization to meet an objective. It does not do it by itself or by collective responsibility - someone has to lead hence the purpose of this requirement. 

These lists tell us something about the nature of quality records, especially by what is not included. Absent from the lists are policies, procedures, instructions, plans, specifications, and any other prescriptive documents. The records all have one thing in common they describe the results of some activity - the results of inspections, tests, reviews, audits, assessments, calculations, etc. However, these lists are dominated by records relating to product quality rather than to the operations of the quality system. In addition to audit records, the following records may need to be maintained to demonstrate the effectiveness of the quality system ... 

It is difficult to decide what should serve as adequate column quality parameters for describing the performance of a set of GPC columns. The two most common measures are plate count and resolution. While both of these can be useful for monitoring the performance of a column set over time, it is not generally possible to a priori specify the performance needed for a specific analysis. This will depend on the nature of the polymer itself, as well as the other matrix components. 

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