Final Product Testing Research Articles

Go/No-Go Testing of VCO Modulation RF Transceivers Through the Delayed-RF Setup

The increasing share of test and packaging as a percentage of the overall cost for RF transceivers necessitate, radically test new approaches to both wafer-level and final production testing. We present a new system-level test setup for voltage-controlled oscillator (VCO) modulating transceiver architectures that we call the delayed-RF setup, along with a novel, all-digital design-for-testability (DFT) modification that enables coverage of the most important system-level specifications. The delayed-RF setup can be used during wafer sort, thus preventing the packaging of nonfunctional dies. Based on this setup and the DFT technique, we present an automatic test development methodology for FM transceivers using frequency-domain signature analysis. We develop two distinct pass/fail criteria based on eigensignatures and envelope signatures and a test generation algorithm that aims at minimizing the required delay while attaining full coverage of target faults. We develop a fault injection and simulation platform for a VCO-modulation, low-IF transceiver architecture using MATLAB and behavioral models including nonideal response. The proposed methodology enables the automation of the test generation process, thus reduces the test development time. Experimental results have shown a 90% reduction in the required delay thereby reducing the cost of this test hardware item

The beadwhacker for maintaining even dispersion of micron-sized beads

This design note describes an automatic device for maintaining an even dispersion of solid phase extraction beads in small volume tubes. The ‘beadwhacker’ is especially designed for use in laboratories developing interfacial chemistries or immunomagnetic separations. The advantages of the beadwhacker include automatic operation, multiple sample capability and reproducible operation for extended periods of time. Furthermore, the device is completely portable and can be placed into a controlled environment, making it useful not only for the testing of final products but also for the synthesis and chemical modification of the beads themselves. The beadwhacker is low cost and constructed from commercially available parts. Preliminary mixing data are presented. Finally, suggestions are given for additional parts that may be necessary if the beadwhacker is to be incorporated as a module in a larger automated system.

Final product testing of rotational moulded natural fibre-reinforced polyethylene

The process of rotational moulding of natural fibre-reinforced polymers (NFRPs) has been developed recently at POLYCOM. This process allows for the use of discrete natural fibres as an efficient reinforcing agent for thermoplastic matrices. In this way, hollow objects with acceptable properties can be produced. The results from different experimental tests carried out on samples taken from rotomoulded cylinders are presented in this paper. Mechanical tests, such as tensile, compression, impact, deep drawing and recovery were performed in order to characterise unreinforced and reinforced natural fibre samples. Other properties, such as environmental stress cracking resistance (ESCR) and shrinkage were also assessed. The results obtained indicate that, in most cases, the properties of natural fibre-reinforced composites are superior to those of the unreinforced ones. In some cases, however, lower mechanical properties have been reported for the reinforced specimens. The testing methodology described here can be used to assess the properties of both reinforced and unreinforced rotomoulded products.

Indirect Methods of Detecting and Evaluating Inclusions in Steel—A Review

Indirect methods to detect and evaluate inclusions in steel are extensively reviewed, which include total oxygen content measurement, nitrogen pickup, steel and slag composition measurement, lining refractory observation, tracer studies of determining exogenous inclusions from slag and lining erosion, SEN clogging and final product tests. There is no single ideal method of detecting and evaluating inclusions in steel, so it is better to use several methods simultaneously to give a more accurate evaluation. Total oxygen content and nitrogen pickup in low carbon aluminum-killed steel as criterion of clean steel in many plants are summarized.

Online Resources for Assessing the Quality and Safety of Dietary Supplements

Vol. 43, No. 4 July/August 2003 Journal of the American Pharmacists Association (www.japha.org) 543 ent labeling, and proper manufacturing practices. Products that pass will be awarded the program’s certification mark. Along with USP, other nonprofit groups, such as Consumer Labs (CL), the National Nutritional Foods Association (NNFA), and NSF International, have established certification programs. A recent review of these initiatives is available at www.supplementquality.com/ testing/Quality_ seals.html. CL (www.consumerlabs. com) provides independent testing of health, wellness, and nutrition products and publishes the results online. To bear the CL Seal of Approval, a product must pass a voluntary certification program. While manufacturers must pay a fee to become certified, test samples are purchased independently from retailers, and blinded tests are conducted at academic or commercial laboratories selected for their analytic expertise. Both NNFA (www.nnfa. org/services/science/gmp.htm) and NSF International (www. nsf.org/dietary) have established GMP guidelines and standards for quality control and assurance, cleanliness, checking the identity and potency of ingredients, and testing of final products for potency, purity, and bioavailability. NNFA’s TrueLabel program is a dietary supplement label registration program required for all NNFA supplier members. Products must be registered in order to be displayed at the annual NNFA Marketplace trade show. Products are subject to random testing by independent laboratories, and companies whose products fail to comply with the association’s standards are excluded from membership. NNFA plans to publish lists of products that fail in its newsletters. Although NNFA’s GMP Certification Program is open only to NNFA members, any company can apply to have their products certified by NSF International. Both groups have similar standards, developed in collaboration with several other industry trade organizations. Lists of certified manufacturers, distributors, and products are available online at the organizations’ respective Web sites. The adoption and implementation of all these initiatives and programs would help ensure documented safety and efficacy, uniform testing standards, GMPs, and professional oversight for dietary supplements and herbal resources.

Effects of hyperbaric exposure on the integrity of the internal components of commercially available cochlear implant systems.

This study investigated whether pressure changes common to scuba diving and to hyperbaric oxygen therapy would not cause crush damage or leakage from critical seals in commercially available cochlear implants. The implanted packages of cochlear implants are susceptible to electrical failure caused by leakage from critical seals and to crush injury when exposed to changing barometric pressures encountered in recreational diving and in hyperbaric oxygen therapy. Six Clarion 1.2, eight MED-EL Combi-40+, six Nucleus CI22M, and six Nucleus CI24M cochlear implants underwent three exposures at 165 feet of seawater (FSW) (6 ata abs), 99 FSW (4 ata abs), and 60 FSW (2.8 ata abs), simulating rates in accordance with U.S. Navy dive tables for nondecompression dives. Dives to 45 FSW (2.4 ata abs) simulated wound therapy. Before each dive began, after each dive, and after completion of the dive protocol, each device underwent telemetry and electrical integrity checks. All implants were returned to their respective factories for final electrical and quality control testing. All 26 devices completed the dive protocol. One Nucleus CI24M implant had a fault recorded at electrode lead 18 on predive and final product testing, which was absent during interval dive measurements. All 26 devices passed final electrical and quality control testing. In addition, the six Clarion units passed repeat helium leak testing. The implanted components of the Clarion 1.2, MED-EL Combi-40+, and Nucleus CI22M and CI24M were safely subjected to repeated pressure changes up to 6 atm abs, equivalent to 165 feet of seawater, without electrical failure from leakage at critical seals or crush damage.

The Food and Drug Administration's perspective on plasma safety.

The balance between acceptable plasma-product safety and the demand for those products involves a finite (but very low) level of risk for transmitting infectious diseases. The Food and Drug Administration (FDA) has focused on the use of a triple safety net to provide safe plasma products. This safety net includes donor selection, plasma testing, and inventory hold (look back and retrieval). Although each part of this safety net contributes to reducing the overall viral load in plasma products, each part may not contribute equally to a safe product in all cases. Donor selection is not universally reliable, and plasma antibody testing can be negative for a disease during its seroconversion window period. However, inventory hold (especially for first-time donors) has added to the usefulness of the other safety-net components. This review article provides a brief overview of each safety component and subsequent related improvements, including advances in antibody testing for donor screening and the addition of PCR testing for donor minipools and viral inactivation procedures during plasma-product manufacturing. Dilemmas created by this safety approach are also discussed, including the debate over zero risk of product versus cost and the impact on donors when they test positive for the various diagnostic tests used. Other dilemmas include the decision to include or exclude currently used plasma tests with the advent of polymerase chain reaction (PCR) testing, expanded use of PCR to test for other plasma-transmitted diseases that impart limited risk to recipients, and the role of antigen/antibody interactions in plasma products, especially as the latter relate to plasma-pool and final-product testing.

Industry Perspectives on the Use of Microbial Data for Hazard Analysis and Critical Control Point Validation and Verification

Microbial testing is an essential element in validation of critical limits identified within a hazard analysis critical control point (HACCP) plan. Without appropriate validation there is no assurance that the plan will control the hazards of concern. Once critical control points have been validated to effectively prevent, reduce, or eliminate hazards, application of routine testing for pathogens in finished product becomes an ineffective means to assure process control and therefore safety of the product. The occurrence of a pathogen in a product produced under an effective HACCP plan is so rare that sampling protocols are not capable of finding the needle in the haystack. Quantitative indicators can provide a much more effective tool for verifying that HACCP is properly implemented. Choice of appropriate indicators is product and process specific. In certain applications, finished product testing for even indicator organisms provides no meaningful data for verification of HACCP (e.g., canned products). Tests chosen should provide meaningful information that directs resources toward prevention and improvement of the system.

Use of simple and complex in vitro models for multiparameter characterization of human blood-material/device interactions

Medical devices, intended for blood contacting applications, undergo extensive in vitro testing followed by animal and clinical feasibility studies. Besides the use of materials known to be intrinsically blood-compatible, the surface of such devices is often modified with a coating in order to improve the performance characteristics during blood exposure. In vitro evaluation of blood-device interactions accompanies the product development cycle from the early design phase using basic material geometries until final finished-product testing. Specific test strategies can vary significantly depending on the end application, the particular study objectives and variables of interest, and cost. To examine the degree to which findings derived from two different in vitro approaches complement one another, this report contrasts findings from a simple multipass loop model with findings from a simulated cardiopulmonary bypass (CPB) model. The loop model consists of tubular test materials, with and without surface modification, formed into valved Chandler loops. The CPB model has an oxygenator with and without surface modification connected to a reservoir and a blood pump. The surface modifications studied in this report are the Carmeda® BioActive Surface and Duraflo® II heparin coatings. Common blood parameters in the categories of coagulation, platelets, hematology, and immunology were monitored in each model. Ideal models employ the optimal level of complexity to study the design variables of interest and to meet practical cost considerations. In the case of medical device design studies, such models should also be predictive of performance. In the more complex and realistic simulated CPB model, experimental design and cost factors prevented easy/optimum manipulation of critical variables such as blood donor (use of paired samples) and heparin level. Testing in the simpler loop model, on the other hand, readily offered manipulation of these variables, and produced findings which overlapped with observations from the more complex CPB model. Thus, the models described here complimented one another. Moreover, conclusions from consistent findings, such as favorable responses associated with the heparin coatings, between the two models were considered to be more robust.

Some Observations on Current and Possible Future Developments in Bioequivalency Testing

Present trends in the evolution of the design and interpretations of bioequivalency studies are reviewed. It is suggested that, although such tests are now being increasingly regarded as clinical mirrors rather than simply quality control tests for final product testing, there is still the possibility of simplifying such procedures. However, care must be exercised to ensure that changes in bioequivalency tests are introduced only after careful public discussions, which should involve both regulators and pharmaceutical scientists from academia and industry. Further, it is important that bioequivalency standards shall be internally consistent and applied in a politically neutral manner.

Revisión: Los residuos en la inspección de la carne Review: Chemical residues in meat inspection

Edible tissues of food animals may contain residues of chemical substances harmful to human health, including animal drugs, mycotoxins and environmental contaminants. Current meat inspec tion activities rely mainly on visual inspection of the carcass and its offals at the slaughterhouse, and fail to detect chemical residues and enteric pathogens that are considered as major health risks associated with meat consumption. In contrast to traditional approaches, application of the hazard analysis critical control point (HACCP) to meat production and inspection, constitutes the best alternative to reduce the incidence of residues and to improve meat safety. Application of HACCP to meat inspection virtually eliminates the need for finished product testing by identi fying the safety risks inherent in the meat production steps, from farm to table, and devising preventive measures which can be monitored in order to control the process. Accordingly, there is also a need for the development and application of analytical methods of enough sensitivity that allow real-time monitoring of chemical residues in live animals and their tissues.

Testing analog and mixed-signal integrated circuits using oscillation-test method

A new low-cost test method for analog integrated circuits, called the oscillation test, is presented. During the test mode, the circuit under test (CUT) is converted to a circuit that oscillates. Faults in the CUT which deviate the oscillation frequency from its tolerance band can be detected. Using this test method, no test vector is required to be applied. Therefore, the test vector generation problem is eliminated, and the test time is very small because only a single output frequency is evaluated for each CUT. The oscillation frequency may be considered as a digital signal and therefore can be evaluated using pure digital circuitry. These characteristics imply that the oscillation-test strategy is very attractive for wafer-probe testing as well as final production testing. In this note, the validity of the proposed test method has been verified throughout various examples such as operational amplifiers, amplifiers, filters, and analog-to-digital converters (ADCs). The simulations and practical implementation results affirm that the presented method assures a high fault coverage.

A Statistical Approach to Blend Uniformity Acceptance Criteria

AbstractRecent Food and Drug Administration (FDA) validation guidelines and comments indicate that applying finished product content uniformity specifications to blend testing is unacceptable. The scenario the FDA has presented is one in which disorder increases as the process progresses so that blend test specifications should be more restrictive (tighter) than finished product testing specifications. In other publications, it has been suggested that finished product assay limits be applied as a blend specification along with a lower relative standard deviation value than the current USP content uniformity limit (6.0%). This approach is questionable since assay results are applied to an aggregate finished product sample rather than individual doses. A method is presented in this paper for applying statistical tolerance limits (Sib) to blend data. This procedure provides a 95% confidence level that at least 90% of the values for the entire population are within the calculated limits. These statistical tol...

Demonstration of 5′-nucleotidase activity in unfixed cryostat sections of rat liver using a combined light- and electron-microscope procedure

In the present study a technique was developed to demonstrate 5'-nucleotidase activity in unfixed cryostat sections of rat liver at the light- and electron-microscope level using a semipermeable membrane. In order to retain the ultrastructure of the unfixed material as much as possible, incubations were also performed at 4 degrees C rather than at 37 degrees C. The optimized incubation medium contained 300 mM Tris-maleate buffer, pH 7.2, 5 mM adenosine monophosphate as substrate, 30 mM cerium chloride as capturing agent for liberated phosphate, 10 mM magnesium chloride as activator and 1.5% agar. At the light-microscope level, similar localizations of 5'-nucleotidase activity were obtained when incubations were performed at 37 degrees C and 4 degrees C. Enzyme activity was present mainly at bile canalicular membranes and at sinusoidal membranes of hepatocytes; total activity was higher in pericentral than in periportal areas. Cytophotometric analyses revealed that specific formation of final reaction product (FRP) (test minus control reaction) at 37 degrees C followed a hyperbolic curve with time. A linear relationship was found between specific amounts of FRP and section thickness up to 8 micrograms. 5'-Nucleotidase activity was about three-fold higher after incubation for 30 min at 37 degrees C than at 4 degrees C. At the electron-microscope level, it was demonstrated that the ultrastructure of rat liver was rather well-preserved after incubating unfixed cryostat sections attached to a semipermeable membrane and electron-dense FRP was found at bile canalicular and sinusoidal plasma membrane of hepatocytes. The most distinct changes in ultrastructure after incubation at 37 degrees C, in comparison with that at 4 degrees C, were the appearance of multi-lamellar structures at bile canaliculi at 37 degrees C. We conclude that the present method is valid for the demonstration of 5'-nucleotidase activity in unfixed cryostat sections of rat liver at both the light- and electron-microscope levels and that hypothermic incubations improve ultrastructural morphology substantially.

Diagnostics of inorganic materials by diffusion structural analysis

In this paper the principle of diffusion structural analysis (DSA), based on the measurements of inert gas migration in solids, is given. The potential of this method and various applications are demonstrated. e.g. the determination of inert gas mobility in metals, ionic crystals and ceramics, characterization of non-crystalline solids and their changes, checking and control of solid state processes taking place during preparation of advanced technology materials, the quality testing of intermediate and final products of these technologies, testing the oxidation and corrosion stability of the materials, etc.

The use of BHK suspension cells for the production of foot and mouth disease vaccines.

The isolation of Baby Hamster Kidney (BHK) 21 cells and their adaptation, characterisation and development for the commercial manufacture of foot and mouth disease vaccines over a twenty year period is reviewed, including the preparation of media, handling of cell substrates and control of the physical environment during manufacture. A description is given of the successful operation of the BHK process which depends on a series of manufacturing stages, all of which make an essential contribution to the final quality of the product and are complementary to the ultimate assessment of quality as defined by final product testing.

Evaluation of diamond radiation dosemeters

The effect of beam energy, dose rate and temperature on seven commercial diamond electrical conductivity detectors was studied. The diamond dimensions were approximately 1 mm*1 mm*3 mm. Clinical photon and electron beams were used for irradiation. The photon energy response normalised to 60Co was observed to have a maximum of 1.37+or-0.06 at 122 keV and the dose rate response was slightly non-linear, in agreement with the theory for insulators. Temperature effects were small and different for each detector. Two of the seven detectors gave repeatable results (+or-5%) over five years, two others were much less satisfactory and three were rejected after preliminary tests. It is concluded that natural diamond can be used for the manufacture of reliable, small and near soft-tissue-equivalent dosemeters but that until the crystal selection and final product testing have been adequately standardised, the user needs to select the reliable dosemeters from a batch.

RED MEAT AND POULTRY INSPECTION: MICROBIOLOGY OF EQUIPMENT AND PROCESSING

The Federal Meat and Poultry Inspection Program (MPIP) requires that equipment be properly designed and cleaned frequently. Cooked ready-to-eat foods must be physically separated from raw foods and held below 40 F or above 120 F except for short periods. Microbiological plant inspections form the basis for microbiological criteria which MPIP is now considering for several commodities. Final product objective surveillance has recently begun on these. Sampling and analysis of final product as a means of protecting the consumer against an infrequent hazard is not feasible. Even hundreds of determinations give unacceptably low protection when the hazard is severe. Control at the source—i.e., at the processing plant—is the practical way to protect consumers with the limited resources available in laboratory programs. The MPIP microbiological sanitation program is a combination of investigation, surveillance, and correction. For example, the 1971 investigations of staphylococcal food poisonings from fermented sausages developed rapidly from final product tests, to investigations of cause, and to bacteriological inspections and corrections.

Analysis of Residual Gases from Television Cathode-Ray Tubes

Analysis of residual gases has been performed on large numbers of production television tubes. This paper describes the system, CRT break-in equipment, and quadrupole RGA sampling procedure. With the system background pressure in the 10−11 Torr range, CRT gases were released, analyzed, and recorded. Included is data on residual gases during the oxide cathode processing, after final tube production and after-life test. The difficulty encountered in relating data on residual gases from final production tubes against the data from life-tested tubes which are at a lower pressure (4–8×10−9 Torr) is outlined along with the effects of phonic desorption of gases during the CRT break-in. The value of residual gas analysis in evaluating the effects of changes in manufacturing processes is discussed.