Quality control meaning

Using method-dependent assigned values for external quality control means having many different target values for the same analyte in the same control serum a very impractical and, from a theoretical point of view, very unsatisfactory procedure which generates many different results for a substance of known molecular weight and with a defined number of molecules. 

If computer-integrated resin handling systems are considered, one must compare their operating procedures with one s process requirements. These process requirements describe the flow of resin and product through the system, which determines the system s electronic architecture. Pertinent considerations include batch vs. continuous operations, the type and number of conveying lines, resin storage and distribution, quality control means and procedures, inventory control, the type and quantity of process parameter sensors, the type and quantity of controlled devices, modes (automatic, semiautomatic, manual, and/or shutdown modes), process information, process management controls, and centralized vs. local operation (Fig. 9-1). 

Internal and external quality control measures are a must in all trace analytical procedures, and an analytical result can only be accepted if all necessary actions in this respect have been carefully considered and the uncertainty on the result evaluated (Chapter 6.1). Quality control may therefore not only be a part of the determination step itself, but must also include the full analytical procedure including sample preparation. Internal quality control means the intra-laboratory procedure for quality control purposes including the control of uncertainty, whereas external quality control means the inter-laboratory comparison of the results of analyses performed on the same... 

A solvent free, fast and environmentally friendly near infrared-based methodology was developed for the determination and quality control of 11 pesticides in commercially available formulations. This methodology was based on the direct measurement of the diffuse reflectance spectra of solid samples inside glass vials and a multivariate calibration model to determine the active principle concentration in agrochemicals. The proposed PLS model was made using 11 known commercial and 22 doped samples (11 under and 11 over dosed) for calibration and 22 different formulations as the validation set. For Buprofezin, Chlorsulfuron, Cyromazine, Daminozide, Diuron and Iprodione determination, the information in the spectral range between 1618 and 2630 nm of the reflectance spectra was employed. On the other hand, for Bensulfuron, Fenoxycarb, Metalaxyl, Procymidone and Tricyclazole determination, the first order derivative spectra in the range between 1618 and 2630 nm was used. In both cases, a linear remove correction was applied. Mean accuracy errors between 0.5 and 3.1% were obtained for the validation set. 

Demand-controlled ventilation (DCV) is one approach to reduce energy consumption due to ventilation, that is gaining popularity in both industrial and nonindustrial applications. It is used in cases where ventilation requirements vary with time, regularly or irregularly. The control is based on a specified level of indoor air quality by means of continuous measurement of the parameters, that are expected to primarily determine the lAQ, such as the concentration of the main contaminant liberated from the production process. The principle is thus similar to the one in some better-known nonindustrial applications, e.g., CO2 levels in rooms with dense human occupancy (theaters, classrooms, etc.) or nicotine concentration in smoking rooms. See also Section 9.6. 

Quality control is often regarded as a post-event activity i.e. a means of detecting whether quality has been achieved and taking action to correct any deficiencies. However, one can control results by installing sensors before, during, or after the results are created. It all depends on where you install the sensor, what you measure, and the consequences of failure. 

Although I have defined terms such as quality control and quality assurance in this chapter, what is important is not the definition but the deeds which it imbues. Whether we call the set of principles I have listed under the heading Quality assurance, Quality Assurance, Quality Improvement or Quality Control makes no difference since it does not change the set of principles. We often seem to invent a term then decide what it means rather than invent or discover a set of principles and think of a suitable name which conveys exactly what we intend without confusing people. Instead of saying Quality control is. .. or TQM is. .. to which there will be many propositions, we should be asking What should we call this group of principles so that we can communicate with each other more efficiently As Shakespeare once said That which we call a rose/By any other name would smell as sweet. ... 

It should also not be assumed that these requirements are only intended for implementation by a department with the title Inspection or Test. Whenever a product is supplied, produced, or repaired, rebuilt, modified, or otherwise changed, it should be subject to verification that it conforms with the prescribed requirements and any deficiencies corrected before being released for use. That is what control means. Control is not just the inspection part of the process and hence quality control , which for years was the name given to inspection departments, was misunderstood. Inspection and test don t control quality. Inspection and test merely measure the quality achieved and pass the results to the producer for remedial action. 

All activities of the overall management function that determine the quality policy, objectives, and responsibilities and implement them by means such as quality planning, quality control, and quality improvement within the quality system (ISO 8402). 

To state the means by which the required life of the coating is to be achieved. This includes surface-preparation standards, paints and systems, application, storage, handling and transport, quality control ... 

Although written reports are the inspecting authority s end product they by no means comprise the whole of the professional service that is supplied or is available on request. The authority s quality assurance objective is likely to be on the lines of client satisfaction allied to compliance with contractual obligations . Although reports are almost certainly monitored, they are a poor indicator of the quality of the examination, and the authority s quality control will rely less on report... 

The term quality control has been widely and loosely employed in the frozen food industry. In the dynamic sense it means the application and control of those techniques of raw material selection, handling, processing, warehousing, and distribution which are known to be required for the production and maintenance of a given level of product quality and condition. 

Process automation implies the real time acquisition and control of process variables such as temperature, agitation, material delivery, or quality control measurements. As far as the MARS system is concerned, a real time process is just like any instrument. The acquisition module merely requires more interactive monitoring, alarms, and control. This can be accomplished by means of a real time multi-tasking data acquisition module. 

It Is now a relatively straightforward matter to analyze commercial pesticide mixtures for nitrosamlne contamination as part of the normal quality control process (2.18). and, as Illustrated above, some of the major contamination problems have begun to be solved by means of technological Improvements. If further research brings about the circumstance In which there Is no detectable N-nItroso compound In any pesticide sold an here, will that mean that pesticide use Is safe from nitrosamlne-formatlon problems I believe that considerably more research must be done before a responsible answer to this question can be given. To elaborate on this position, let me focus on the herbicides for a moment. 

Off-the-shelf catalogue sales of micro reactors have just started [15]. With an increasing number of commercial products, quality control will become more important. Brandner et al. describe quality control for micro heat exchangers/reactors at the Forschungszentrum Karlsruhe [23]. All manufacturing steps are accompanied by quality control and documentation. Leak rates (down to 10 mbar 1 s for He) and overpressure resistance (up to 1000 bar at ambient temperature) are measured. Under standardized conditions, the mean hydraulic diameter is determined. Dynamic tests supplement this quality control. 

High quality is one of the criteria defined in the requirements section above. Since the program should run automatically in batch mode, we mean by quality control an internal check of the 3D structures produced by the structure generator itself. In general, the abilities of a fast, automatic structure builder to assess the quaUty of its models are rather limited since, for example, an exhaustive conformation analysis and energy optimization is impossible in most cases. However, there are a Umited number of simple quaUty checks to avoid trivially distorted structures ... 

Particularly for direct microanalytical techniques using <10 mg of sample for analysis, it is highly desirable to obtain quantitative information on element- and compound-specific homogeneity in the certificates for validation and quality control of measurements. As the mean concentration in a CRM is clearly material-related, the standard deviation of this mean value should represent the element s distribution in this matrix rather than differences in the analytical procedures used. 

Quality control unit means any person or organizational element designated by the firm to be responsible for the duties relating to quality control. 

Apart from routine quality control actions, additive analysis is often called upon in relation to testing additive effectiveness as well as in connection with food packaging and medical plastics, where the identities and levels of potentially toxic substances must be accurately known and controlled. Food contact plastics are regulated by maximum concentrations allowable in the plastic, which applies to residual monomers and processing aids as well as additives [64-66]. Analytical measurements provide not only a method of quality control but also a means of establishing the loss of stabilisers as a function of material processing and product ageing. 

As indicated in Section 6.2.2, DI-CIMS suffers from poor reproducibility. For nonvolatile additives that do not evaporate up to 350 °C, direct quantitative analysis by thermal desorption is not possible. The method depends on polymer formulation standards that are reliably mixed. Wilcken and Geissler [264] described rapid quality control of l- xg paint samples by means of temperature-programmable DI-EIMS with PCA evaluation. 

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