Physical samples

Physical samples include air samples, surface wipes and smears, and other materials from the workplace that can be used to ideirtily the physicochemical form of radioactive contarrrinants. Assessments of iirtakes based on activity in physical samples ate particirlarly rmcertain because of the large variability in workplace conditiotts and the potential for irrtakes by individuals. Furthermore, assessment must 

Air samples may be drawn from the ambient room atmosphere by fixed samplers, or from the breathing zones of workers by personal air samplers (PASs). For compounds that disperse readily in air, such as radioactive gases and vapours (e.g. 

More representative samples will be derived from PASs, which are self-powered systems carried by the worker that draw samples from the immediate breathing zone at a regular rate. Even these samples, however, may lead to over- or under-estimation of intakes, depending on the applicability of assumptions about particle size and breathing rates. To reduce this uncertainty, some PAS systems prevent particles of non-respirable size from reaching the filter [15]. 

Both forms of sampling rely on the extraction of radioactive material from the passing air on a collection medium. This medium will be specific, to some extent, to the material to be collected. For example, particulate material can be removed on coarse fibre filters, while charcoal beds are employed to sample radon gas and iodine vapour, and tritiated water can be collected in a water trap. 

Analysis of the particle size and solubility of samples of airborne radioactive material can assist in the development of biokinetic models for dose assessment (Section 6). Direct comparison of air samples with values of derived air concentrations (Section 2) can be used as an input to the evaluation of workplace conditions and to the estimation of doses. 

---

Equal suspension of particles referenced to visual appearances and physical sample testing. Empirical correlations generalized to apply to most problems. 

EC Type-examination Certification Certification of design based on testing of physical samples versus standards/essential requirements EC Verification Certification... 

The EC type-examination is the process that the manufacturer may use to obtain independent verification that a design conforms to essential requirements, when a certified QA system has not been applied to the design process. The manufacturer must submit an application to the notified body, accompanied by documentation on the device design and physical samples of the device. The Notified Body examines the... 

Physical sample pretreatment. Almost all test samples, including those which are measured by so-called direct techniques , need physical pretreatment in any form. The most applied physical techniques are ... 

Torrie, G.M. Valleau, J.P., Non-physical sampling distributions in Monte-Carlo free-energy estimation - umbrella sampling, J. Comput. Phys. 1977, 23,187-199... 

It is even possible for an individual noise pulse to exceed — ET so that a negative reading of Ex will be obtained. This happens in the real world and therefore must be taken into account in the mathematical description. This is a good place to also note that since the transmittance of a physical sample must be between zero and unity, Es must be no greater than If, and therefore when If is small an individual reading of Es can also be negative. Therefore it is entirely possible for an individual computed value of T to be negative. 

Figure 3.9 Crab sampling in different practical manifestations (aggregate material), to which must be added all PAT sensor alternatives in Figures 3.12-3.14 dealing with fluids and slurries. All principal characteristics are identical for physical sampling and signal acquisition there is only sampling from some part of the stream cross section. This creates IDE and therefore cannot result in representative sampling.

The variogram function is not defined for lag = 0 - which would correspond to extracting the exact same increment twice. Even though this is not physically possible, it is highly valuable to obtain information of the likely variance corresponding to this zero-point variability (i.e. what if it would have been possible to repeat the exact same physical sampling). The TOS identifies this variance as MPE (minimum practical error), which is also known as V(0). 

If the sample is a hquid, sohd or paste and is amenable to physical sampling, then an ETlR-based analyzer equipped with an ATR probe or accessory will provide a good method of measurement. 

The replicate sample trap This occurs when replicates of the same physical sample are present in both the selected subset and the rest of the samples. This usnally leads to overly-optimistic cross-validation results, because representatives of the same samples are present in both the model and... 

The FDA investigators have the authority to collect samples as described under the comphance program 7348.808. Samples of a test article, the carrier, the control article or test and control article mixtures may be selected and sent to FDA laboratories to determine the identity, strength, potency, purity, composition, or other characteristics that wiU accurately define the coUected sample. In fact, even physical samples such as wet tissues, tissue blocks, and slides may be collected. When the field investigator collects a sample of any chemical substance, he will also coUect a copy of the methodology from the sponsor of the testing facihty. The copy of the methodology will be sent to the FDA laboratory selected to perform the sample analysis. 

The significance of test results depends to a considerable extent on how the physical sample was obtained. Whatever the purpose of testing, it is necessary to question whether the samples tested adequately represent the population being investigated. In many cases, one is limited by the amount of material available, there may be only one product or batch to be evaluated, but in routine quality control there is the added dimension of needing to sample repetitively in time. This means that a good measure of... 

Sample A sample is a physically synthesized compound—the product that a chemist produces. A compound represents a structure on paper before it is synthesized through chemical reactions. The compound is instantiated when a physical sample is produced. CRS registers physically synthesized compound samples. 

Chemical Laboratory Sample Identifier (LSI) An identifier that uniquely identifies a chemical sample. Although the format of sample identifier differs from organization to organization, it usually consists of five parts a prefix that specifies the sample s source (e.g., synthesized internally or acquired from external sources) a base that uniquely specifics parent structure a form that indicates whether a chemical sample is a free base or with salt, radiolabeled, or a formulation a parity bit checksum that is derived from the combination of prefix, base, and form using a check-sum hash algorithm and a batch or a lot number that identifies the actual physical sample. 

Batch—for a given Prefix, Base, and Form combination, specifies the actual physical sample of the compound that is synthesized in a specific chemical reaction. 

Sample ID—combination of Compound ID and Batch. Uniquely identifies the physical sample. 

The investigator collects a physical sample of a product and requests shipping records documenting its distribution. The investigator will leave a receipt for any physical samples collected. 

Physical uniformity criteria Criteria for fluid mixing which involves physical sampling of tank contents or estimation of pumping of tank contents or estimation of pumping capacity and/or velocity values. 

Have any physical samples (blood, urine, feces) been collected If so, where are they ... 

Depending on the data system involved, at least the first two options are available to a user. There may also be a sample number to link the injection to the physical sample used for analysis. 

---