Specific Instrumental Function

we compare these instrumental profiles calculated with the proposed method and with the convolution approach. Secondly, a fine difference between an exact solution and a solution based on the convolution approach is demonstrated. 

The approximation for the specific instrumental function for the flat specimen aberration as given by Cheary et al. and Ida and Kimura is  

Of some interest is to consider the coupling effects by the example of the flat specimen aberration and finite width of the receiving slit. Assuming the size of the receiving slit in the axial direction is negligibly small (that means x = 0), and taking into account Xf=0, T/=0, x = 0, we obtain from Equation (16) the following equation  

Setting y = d we obtain the equation linking angle (p and equatorial positions ys on the sample from which the diffracted rays hit exactly on the boundary of the receiving slit. 

2 Axial Aberration. The equation of the conic for the case that points Ai and A2 have only axial components can be obtained from the general Equation (16) by setting their equatorial components jy, to 0. 

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The OQ/PV should be performed on installation, after extended use (e.g. at least once per year) and after major repair. This may also be extended to performing an OQ/PV before starting to validate or optimise a method on that instrumentation. OQ/PV for a capillary electrophoresis instrument should therefore be directed towards those specific instrumental functions which can affect the CE analysis. 

There are two different approaches for calculation of the instrumental function. The first is the convolution approach. Proposed more than 50 years ago, initially to describe the observed profile as a convolution of the instrumental and physical profiles, it was extended for the description of the instrumental profile by itself According to this approach the total instrumental profile is assumed to be the convolution of the specific instrumental functions. Representation of the total instrumental function as a convolution is based on the supposition that specific instrumental functions are completely independent. The specific instrumental functions for equatorial aberrations (caused by finite width of the source, sample, deviation of the sample surface from the focusing circle, deviation of the sample surface from its ideal position), axial aberration (finite length of the source, sample, receiving slit, and restriction on the axial divergence due to the Soller slits), and absorption were introduced. For the main contributors to the asymmetry - axial aberration and effect of the sample transparency - the derived (half)-analytical functions for corresponding specific functions are based on approximations. These aberrations are being studied intensively (see reviews refs. 46 and 47). 

The main difference between the proposed method and the convolution approach (in which the line profile is synthesized by convolving the specific instrumental functions) lies in the fact that the former provides an exact solution for the total instrumental function (exact solutions for specific instrumental functions can be obtained as special cases), whereas the latter is based on the approximations for the specific instrumental functions, and their coupling effects after the convolution are unknown. Unlike the ray-tracing method, in the proposed method the diffracted rays contributing to the registered intensity are considered as combined (part of the diffracted cone) and, correspondingly, the contribution to the instrumental line profile is obtained analytically for this part of the diffracted cone and not for a diffracted unit ray as in ray-tracing simulations. 

The specific instrumental function for the axial aberration can be analytically calculated for the special case in which there is no divergence of the incident rays ... 

A simplified consideration is given by Ida and Kimura" and Cheary, Coelho and Cline.The specific instrumental function for the sample with a thickness of T is given as ... 

In a GLP-compliant laboratory, a data system must meet explicit requirements guaranteeing the validity, quality, and security of the collected data. Operational qualification (OQ) must be performed after any new devices are installed in the laboratory system and whenever service or repair are performed. The role of OQ is to demonstrate that the instrument functions according to the operational specifications in its current laboratory environment. If environmental conditions are highly variable, OQ should be checked at the extremes in addition to normal ambient conditions. Performance qualification (PQ) must be performed following any new installation and whenever the configuration of the system has been changed. PQ demonstrates that the instrument performs according to the specifications appropriate for its routine use. 

Since the vendor s functional specifications are usually defined for a specific instrument component, the OQ is usually also performed on an individual component basis. This is one of the things that sets the OQ apart from the PQ, which is described later. 

The terms instrument qualification and instrument validation are sometimes used indiscriminately. In this chapter, the term qualification refers to the site preparation and the testing employed to demonstrate that the instrument is properly installed in a suitable environment and the performance meets the predetermined specifications for its intended use. Qualification is a part of the whole validation life cycle. Validation refers to the process to provide assurance that the instrument is suitable for the intended application throughout the lifetime of the instrument. Installation qualification (IQ), operation qualification (OQ), and performance qualification (PQ) are performed to provide evidence that the user requirement specifications (URSs), functional requirement specifications (FRSs), and design qualification (DQs) have been met. The sequence of requirements setting and qualification events as well as the relationships between IQ, OQ, PQ and URS, FRS, and DQ are generally illustrated by the V diagram shown in Figure 2. Installation qualification demonstrates the fulfillment of the DQ. Similarly, OQ demonstrates the fulfillment of the functional requirements and PQ demonstrates the fulfillment of the user requirements. 

Performing an operational qualification procedure ensures that the specific parts of an instrument are functioning according to defined specifications for precision, linearity, and accuracy. For operational qualification, testing individual instrument parameters and comparing them to accepted values requires isolating each parameter. Each parameter is related to a specific CE function. Typical CE functions that are subjected to qualification and their associated parameters are shown in Figure 12.2. 

Standardized questionnaires are used to capture HRQL data in a variety of settings. These standardized questionnaires may be self-administered or completed via telephone or personal interview, by observation, or by postal survey. Two basic approaches to HRQL measurement are available generic instruments that provide a summary of health-related quality of fife and specific instruments that focus on problems associated with individual disease states, patient groups, or areas of function. 

To evaluate aspects of HRQL that are specific to a particular disease or condition, specific measures also may be used. Specific measures include only important aspects of HRQL that are relevant to the patients being studied, such as the loss of function patients experience from asthma or the amount of pain they have from arthritis. Disadvantages of using specific measures are that they are not comprehensive and cannot be used to compare across conditions. They also cannot measure unforeseen side effects or conditions. Examples of specific instruments for heart failure are the Minnesota Living with Heart Failure Questionnaire and the Chronic Heart Failure Questionnaire (Guyatt et al., 1989 Rector, Kubo, and Cohn, 1987). 

In the past, although FTIR and ESCA were known to offer a great deal of information on specific chemical functional groups of surfaces, little application was made of these analytical tools in the field of conservation and restoration science and technology. A survey of instrumental analysis citations since 1953 in the conservation literature showed that only one FTIR work was published in Studies in Conservation in 1977 and two ESCA papers were published in Archaeometry in 1976. None appeared in Arts and Archaeology Technical Abstracts (AATA). 

Manufacturers can greatly assist the user by providing operational qualification/performance verification (OQ/PV) procedures to be performed on site to check the instruments performance. When an OQ/PV test procedure is developed for an instrument it is important to identify and test those functions of the instrument which have a direct effect on its ability to perform the analyses it was intended to undertake. This is sometimes confused with testing the instrument for conformity with instrumental specifications, but as previously stated the instrumental specifications are linked to the DQ phase and not subsequent use. The instrumental functions tested in OQ/PV are those which affect the qualitative and quantitative data required from the analysis. 

When alerted to a control problem, the first step should be to carefully inspect the analytical method, equipment, reagents, and specimens. Does everything look, feel, smell, and sound correct An inspection may seem to be a very qualitative and subjective technique, but it can be exceedingly useful when performed with checklists developed for specific analytical methods. This inspection should include a review of records documenting changes that occur with the instrument and reagents. Brief instrument function checks are often performed to verify proper system performance and to separate chemical and instrumental sources of errors. An experienced analyst can often spot the problem by making this kind of inspection, whereas inexperienced analysts will be aided by formal checklists. 

It seems reasonable to assume that, from a functional point of view, the appearance of species with the ability to acquire drives for unnatural goals was the last radical turning-point in the development of brain organization. In the animal kingdom the new mechanism reached its functionally most sophisticated level in the group of anthropoid apes, but it reached perfection in Homo sapiens only. The new mechanism culminated in the development of speech - the classic, human-specific instrument that made interpersonal communication possible by capturing reality in the form of symbols - and thus opened the way for the operation of an unrestricted variety of acquired drives. 

The profile of diffraction peaks depends on two types of contributions first, the instrumental function and, second, the stractural defects that also lead to changes in the intensity distribution. This last comment is at the core of microstructural analysis, which will be the subject of the second part of this book and will not be discussed here. Peak profiles can be described by a function h(e), where the e variable corresponds in every point to the difference with respect to the theoretical diffraction angle. The function h(e) can be expressed as the convolution product of f(e), which represents the pure profile associated with the sample s specific effects, and g(e), which constitutes the instrumental function. The function h can then be expressed as ... 

The essential drawbacks of network analysis are the high costs and large dimensions of commercial equipment, which has to satisfy the requirements of universal application such as large frequency range and different measurement principles. Acoustic sensors as a particular apphcation case do not require many of those instrument functions. The specific requirements have been reahzed in new network analyzer-based sensor interface circuitry. 

This chapter provides an overview of mass spectrometer function and operation. It describes specific instrument types with demonstrated or potential application for measuring radionuclides and surveys the application of these instruments to radionuclide detection. Finally, it discusses the circumstances under which use of mass spectrometers is advantageous, the type of mass spectrometer used for each purpose, and the conditions of sample preparation, introduction and analysis. Its perspective is from a national laboratory active in environmental and non-proliferation monitoring. It emphasizes isotope ratio measurements, but mass spectrometric measurements also provide isotope mass information. Several recent books describe elemental and isotope ratio mass spectrometry in far greater detail than is presented here (Barshick et al., 2000 De Laeter, 2001 Montaser, 1998 Nelms, 2005 Platzner, 1997 Tuniz et al., 1998). High-resolution mass spectrometry forms the basis of the mass scale used for elemental and isotopic masses (Coplen, 2001), but this application of MS falls outside the scope of this chapter. 

Some passive controls will live outside the user interface and may not be apparent to day-to-day operators. For example, HIT systems typically need to exhibit resiliency in their architecture whether brought about through redundancy or other systematic means. These design features represent active engineered controls. However it is common for this to be supported by other more passive controls which require some degree of human intervention. The platforms on which systems reside can often be monitored for availability and performance. In some cases systems may be specifically instrumented to provide metrics on the execution of specific functions or the success of database transactions. Similarly systems may log errors or failed messages which are then made available for inspection by service management personnel. 

Allocation of the safety requirements to the safety instrumented functions and development of safety requirements Specification... 

Safety instrumented functions are derived from the safety function, have an associated safety integrity ievei (SiL) and are carried out by a specific safety instrumented system (SiS). For exampie, ciose vaive XY123 within 5 s when pressure in vessei ABC456 reaches 100 bar . Note that components of a safety instrumented system may be used by more than one safety instrumented function. 

The targets for average probability of failure on demand or frequency of dangerous failures per hour apply to the safety instrumented function, not to individual components or subsystems. A component or subsystem (for example, sensor, logic solver, final element) cannot have a SIL assigned to it outside its use in a specific SIF. However, it can have an independent maximum SIL capability claim. 

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