bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microwave assisted hydroxyalkylamidation of poly(ethylene‐co‐acrylic acid) and formation of grafted poly(ϵ‐caprolactone) side chains
Authors: Sinnwell Sebastian , Ritter Helmut 
Published: July 2007

AbstractThe microwave assisted amidation of poly(ethylene‐co‐acrylic acid) (PEAA) with 2‐(2‐aminoethoxy)ethanol was performed to yield a hydroxy functionalized poly(ethylene) based copolymer (PEAAOH) in a single step. PEAAOH was used as a polyinitiator for the ring‐opening polymerization of ε‐caprolactone. The obtained graft copolymers were studied via 1H NMR spectroscopy, gel permeation chromatography, differential scanning calorimetry, polarized optical microscopy, and scanning electron microscopy. Microscopy methods show a crystallization behavior of banded spherulites. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3659–3667, 2007
Theoretical modeling of the relationship between Young's modulus and formulation variables for segmented polyurethanes
Authors: Ginzburg Valeriy V. , Bicerano Jozef , Christenson Christopher P. , Schrock Alan K. , Patashinski Alexander Z. 
Published: July 2007

AbstractWe describe a new modeling approach to prediction of Young's modulus of segmented polyurethanes. This approach combines micromechanical models with thermodynamic considerations based on the theory of block copolymers. The resulting model predicts both the equilibrium morphology and the “ideal” Young's modulus of a segmented polyurethane polymer as a function of its formulation (hard segment chemical structure, hard segment weight fraction, soft segment equivalent weight) and temperature. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2123–2135, 2007
Methods and limitations of assessing the hermeticity of semiconductor component encapsulations
Authors: Merrett R. P. 
Published: July 2007

AbstractHermeticity testing is a standard part of the process control and procurement procedures for semiconductor components. The various test methods are reviewed and particular emphasis placed on their limitations. It is shown that, although the commonly used tests are incapable of detecting all of the leaks which pose a reliability hazard, these tests can be used to identify batches in which an unacceptably large fraction of the packages are likely to have such leaks.
Estimation of weibull reliability from few life tests
Authors: Erto Pasquale , Guida Maurizio 
Published: July 2007

AbstractThe 2–parameter Weibull model can be re–parameterized in terms of shape parameter and a prefixed age for which a reliability estimation is required. Using the uniform and beta priors, some new point and lower bound reliability estimators were derived. These estimators appear to be very suitable to meet the needs of fast and cheap reliability evaluation during production. Their characteristics were studied by means of a Monte Carlo simulation and were compared with those of the maximum likelihood estimators.
A failure analysis methodology for revealing esd damage to integrated circuits
Authors: Taylor R. G. , Woodhouse J. , Feasey P. R. 
Published: July 2007

AbstractA range of chemical and physical techniques is required in order to identify the failure sites and failure machanisms of ICs subjected to ESD transients. The damage features of ESD failures from the field are shown to be similar to those produced by simulated human‐body‐model testing. A curve tracer technique can be used to predict the location of an ESD failure site in the input or output circuit of an IC. Junction shorts induced by ESD transients form as a result of a combination of heating at the site of second breakdown, together with the heat generated by the discharge current in the discharge path. The ESD sensitivity of a given input or output circuit is dependent on the spacing between the input contact window. and the contact window of the nearest diffusion‐to‐Vss metallization.
The reliability engineer looks at stress screening
Authors: Tustin Wayne 
Published: July 2007

AbstractStress screening (as a final step in the manufacture of electronics) adds brief intervals of severe broadband vibration to temperature shock. The goal is to precipitate as hard defects any latent manufacturing defects. Applying such stressing to subassemblies and assemblies is much faster and much more effective than the more familiar ‘burn‐in’ or temperature shock alone.
Reliability analysis of fault tolerant memory arrays
Authors: Nachlas Joel A. 
Published: July 2007

AbstractA model is developed to represent computer memory module reliability as a function of memory array reliability under a fault tolerant design. The fault tolerance feature of the array actually results from a revision in the use of the array so that with respect to some failure modes, the array becomes a K out of N rather than a series system.The model is used to determine array reliability under fault tolerance. The ratio of module reliability under fault tolerance to that without this feature is used as a measure of the benefits of revising array use. A key feature of the analysis is the fact that not all faults can be tolerated.The elemental memory devices examined conform to a decreasing Weibull hazard model. Consequently, evaluation of the general model for the K out of N system realized must be done numerically. However, for the special case in which K=N‐1, a closed form expression for the performance measure is obtained. This special case occurs for the application of interest and it is shown that the performance measure always exceeds one and depends directly upon the proportion of faults that can be tolerated.Thus the value of fault tolerance is shown to depend upon the extent to which the array will tolerate faults. This provides a basis for deciding whether or not fault tolerance should be implemented.
A general model for age acceleration during thermal cycling
Authors: Nachlas Joel A. 
Published: July 2007

AbstractConventional practice in evaluating the effect of elevated temperature upon electronic devices in either accelerated testing or stress screening is the use of the Arrhenius reaction rate equation. This equation fails to represent several key aspects of the stress. A general model that includes the reaction rate effects during heating and cooling, the mechanical effects of heating and cooling, and non‐constant activation energies is provided here. The model is based upon a general representation of a thermal cycle.Once the general model is constructed, it is shown to accommodate as special cases, acceleration when one or more of the features is assumed absent. An example illustrates this point. Then several uses for the model beyond the computation of the acceleration factor are discussed. It is suggested that the general model can be used to support test design and equipment selection decisions. The model therefore provides a more realistic portrayal of the effects of a thermal cycle and increased decision flexibility in defining thermal stress regimens.
Reliability of a dynamic random access memory (dram)
Authors: Hale P. W. 
Published: July 2007

AbstractThe occurrence of electronic failures during high temperature stress testing, and their recovery at ambient, represents one of the most difficult problems of reliability assessment. This paper examines one such failure on a dynamic random access memory (DRAM) module and gives an analysis of its nature. In addition, a suggestion as to how to assess the impact of such failures in the field situation is given and its specific application to this problem used to make a field reliability prediction.
Integrated circuits for submarine communication systems, their design and development
Authors: Tew A. J. 
Published: July 2007

AbstractDigital optical systems represent the current advance in submarine communications. Modern system designs require rapid evaluation of new components without relaxation of the stringent reliability requirements demanded for submarine applications. This article describes the development of integrated circuits (ICs) for submarine use. It goes on to show the design methodology, and discusses some limitations and the demanding reliability assurance aspects. The current IC designs are being used in both long‐haul and short‐haul links. The technology discussed is providing a major role in the future development of high‐capacity optical submarine systems.
Using statistical control charts for software quality control
Authors: Gardiner John S. , Montgomery Douglas C. 
Published: July 2007

AbstractThis paper describes the use of Shewhart U charts for controlling software quality while the software is under development. A parallel between the software development process and a complex manufacturing process is developed. This allows the use of statistical control charts to monitor the software development process.The general approach is to let observed defect data represent a sample of the true but unknown state of the entire software project. Software quality data so obtained can be used to derive a meaningful statistical interpretation of the state of the development project. Based upon this interpretation management can take action to improve the overall software quality while in the development stages.
A note on the average run length of cumulative sum control charts for count data
Authors: Gardiner John S. , Friedman David J. , Montgomery Douglas C. 
Published: July 2007

AbstractThis note presents preliminary results on the average run length (ARL) of a Cumulative Sum Control Chart (CUSUM) used to monitor defects or counts, when the count distribution is Neyman Type‐A. The ARL for this distribution is contrasted to the more customary Poisson model for counts or defects. We show that the ARL curve of a Neyman Type‐A CUSUM always lies below the ARL curve of a Poisson CUSUM.
A rapid technique for assessing the moisture ingress susceptibility of plastic‐encapsulated integrated circuits
Authors: Chwastek E. J. , Shaw R. N. 
Published: July 2007

AbstractThe equipment and associated methodology of a new technique for checking the susceptibility of plastic‐encapsulated ICs to moisture ingress is presented. The basis of the new technique is to immerse unbiased ICs in a salt solution and to subject them to high temperatures (in the range 120°C to 175°C) and to high pressures (2 to 9 atmospheres). At the highest temperature, results can be obtained within a few hours, although a 20 h test at 165°C is suggested as a screen for components. The test is extremely simple to carry out and a testing facility can be quickly established. Using CMOS components from five different vendors, good agreement has been obtained between the results from the new test and the results from a biased 85°C/85 percent RH test.
Estimation and test for the parameters of the arrhenius model
Authors: Hartler Gisela 
Published: July 2007

AbstractEstimation and test procedures are given for the parameters of the Arrhenius model. The assumed failure distribution is of exponential or Weibull type with fixed and temperature independent shape parameter. The approach is based on failure terminated experiments on at least two different tempera‐ture levels with pre‐assigned and equal number of failures for each temperature level. Estimation consists of two steps, modified maximum likelihood estimation followed by ordinary least squares regression. Statistical tests are defined on acceptance regions given in the particular parameter space by circles or ellipses depending only on the experimental design.
Height‐keeping reliability of aircraft at high altitude
Authors: Cannell W. P. 
Published: July 2007

AbstractIncreasing congestion in high altitude air routes has led to an expectation of large financial benefits from a reduction in separation standards, which will enable more aircraft to fly closer to their optimal altitude. The safety of reduced separation depends mainly on the reliability of aircraft height‐keeping, which is itself the product of a number of different airframe, instrument and pilot‐related errors. This is the subject of an international programme of studies under way in Europe, Japan and the United States. A review of studies being carried out in Europe is presented, indicating some of the problems encountered.
A mechanical decapsulation technique for epoxide‐packaged semiconductor components
Authors: Chwastek E. J. , Holland I. A. 
Published: July 2007

AbstractA novel mechanical technique for decapsulating plastic semiconductor components has been developed. The technique is extremely easy to use, has a high success rate, and is superior in all respects to previously‐described mechanical techniques which give inconsistent results. A significant advantage over alternative chemical techniques is that corrosion products on the die surface are retained.This paper describes the new technique and shows examples of new and corroded components that have been successfully decapsulated.
Worst case product performance verification with electromagnetic interference test applications
Authors: Breyfogle Forrest W. , Davis Jim H. 
Published: July 2007

AbstractWhen many variables are prevalent, it is difficult systematically to identify the optimum configuration for product certification. This need can occur in areas such as testing performance of closed‐loop servo systems and testing products for electromagnetic interference (EMI). This paper proposes a test strategy to identify a 'determined worst case expected' product configuration and a criterion for pass/fail. The process was developed originally for EMI test applications; however, it can also be useful for other product performance specifications.
The effect of pretinning on the strength of a chip carrier solder joint
Authors: Ohlsson Susanne 
Published: July 2007

AbstractPretinning of gold‐plated components is often done to avoid the formation of brittle Au/Sn intermetallic compounds, which may lower the mechanical strength of the joints. In this investigation the reliability of 32LCCs surface mounted on alumina boards is tested in internal and external temperature cycling, as well as in shear tests, and the effect of pretinning is studied. One thousand times of temperature cycling between −55 and +125°C and 2000 h of power cycling with an upper joint temperature of +75°C did not cause any electrical opens.Shear tests made after a 168 h heat treatment at +125°C and 1000 temperature cycles showed that forces of approximately 1000 N were required to break the chip carrier joints. The microstructure of Sn62/Pb36/Ag2 solder joints containing gold was examined and the existing phases were identified using electron diffraction X‐ray analysis. The joints fail at the Au/Sn intermetallics at the chip carrier metallization or at the Cu/Sn compounds formed at the substrate thick film/solder interface. No deterioration of the overall joint strength due to Au/Sn intermetallics was seen, when the gold content in the joints was approximately 4 weight per cent.
Subsurface burnout mechanisms in gallium arsenide (GAAS) electronic devices
Authors: Anderson W. T. , Morgan D. V. , Buot F. A. , Christou A. 
Published: July 2007

AbstractThis paper reviews the present knowledge on subsurface burnout mechanisms in Gallium Arsenide (GaAs) electronic devices. The results of the work should assist in the creation of more reliable devices with greater radiation hardness.
Reliability and failure patterns arising from fatigue
Authors: Carter A. D. S. 
Published: July 2007

AbstractThis paper examines the cause of ‘knees’ or ‘freaks’ in the life‐failure patterns resulting from some fatigue processes. A theory is developed which takes into account the extra fatigue damage associated with the non‐elastic behaviour of the material. It appears to account for the knee and agrees well qualitatively with test results, though quantitative comparisons are not possible because the stochastic data required for the calculation are not available. It is shown that ‘S’‐shaped curves sometimes experienced at higher loading roughness are also due to the same mechanism. The theory suggests that the undesirable features of the failure patterns, whose origin has not hitherto been fully investigated, can be eliminated by a design which is intrinsically reliable with respect to the elastic limit (or with respect to the yield strength if a small loss of reliability is acceptable). Because the knees or freaks appear to be a consequence of the fatigue process and arise with conventionally distributed mechanical properties it is suggested that this design action would be more effective than eliminating the items by quality control.
Reliability assessment of dispenser‐type thermionic cathodes
Authors: Stevenson John L. , Aagesen Svend M. , Lotthammer Rolf , Kornfeld Günter 
Published: July 2007

AbstractAn extensive analysis has been performed of life test results obtained in the long‐term (15,000 h) operation of both tungsten matrix and tungsten‐osmium matrix dispenser cathodes. Sensitive indications of potential life capability for these cathodes are shown to be available via systematic interpretation of temperature‐limited emission characteristics over time. These characteristics follow Arrhenius law temperature dependencies, with activation energies either identical with or closely similar to those determined separately for active material dispensation from these cathodes. Optimum temperature settings are determined, for each cathode type, at which projected life is maximized. Only modestly accelerated constant stress and step‐stress results yield credible reliability projections at these optimum operational temperatures. Furthermore, there remains some uncertainty concerning the application of a (time)½ dependence to all data generated in testing of the tungsten‐osmium, mixed metal matrix cathodes. Nevertheless, it is demonstrated that such cathodes can have mean lifetimes of at least 12 years, and may reach 20 years of serviceable life, sustaining only minor levels of degradation.
Logistics support analysis or computer‐aided gold digging
Authors: Johansson P.‐O. , Wååk Olof 
Published: July 2007

AbstractFor a number of years the Swedish State Railways (SJ) has been involved in life cycle cost (LCC) acquisitions.1 The best known example is the recent acquisition of rapid trains. Logistics support analysis (LSA) is a natural supporting activity and a number of analyses have also been performed on existing material. This kind of analysis was previously done only to a minor extent. Therefore it is not surprising that the potential for cost‐effective improvements has been very large — in fact larger than expected.This paper will report from three different investigations, each of which illustrates various types of improvements in the existing logistics support system. These three investigations are
Spares holding of pantographsA pantograph is the item that connects the electric driven locomotive with the power line.

Analysis of the automatic train control (ATC) system
Logistics support analysis of traction engines.
The major conclusions from the studies are twofold:
This type of analysis is very profitable, and the present availability of computer support in fact makes it even more so.
There are a number of practical and organizational problems linked to the introduction of such analyses. SJ is not unique in having these kinds of problems.
Safety first — profits last?
Authors: Butler Basil 
Published: July 2007

AbstractMr Basil Butler, Managing Director of the British Petroleum Company plc, recently addressed a meeting of the British Institute of Management on the subject of safety and how it relates to profits. In our view, it was an excellent speech which deserves a wider audience and should be of particular interest to practising quality and reliability engineers.The Editors are indebted to Mr Butler and to BP for permission to publish the address in full.
User control of electronic component reliability in spacecraft applications
Authors: Gorton H. Clay 
Published: July 2007

AbstractThis paper elucidates the role of the electronic component engineer in ensuring the reliability of electronic components for high reliability spacecraft applications. The reliability of electronic components is categorized in three areas of responsibility, attributable to the component manufacturer, the user and a shared responsibility between the two. The broad scope of the component engineer's responsibility extends from circuit design to system operation. Co‐operation with circuit design engineers for proper part application is emphasized, and the requirements for understanding the effects of environmental stresses on device material properties is treated. The importance of a close working relationship between the component engineer and the part supplier is also emphasized.
A computer system for the analysis of integrated circuit reliability
Authors: Mauri P. 
Published: July 2007

AbstractThe formulation of total reliability assessment of integrated circuits involves an increasing amount of knowledge and data and hence it requires increasing computerized assistance. To perform this an information system has been designed and implemented. Following engineering practice, the key features of the system are (a) the collection of different types of data, e.g. electrical parameter measurements and qualitative description of the mode and the mechanism of failure and (b) the implementation of procedures coming from methods often applied, e.g. statistical or new approaches, such as formalization of cause—effect chains as studied for artificial intelligence applications. The system architecture has been designed so as to allow direct user maintenance, and hence a quick updating of reliability knowledge and information. Furthermore its modularity eases the implementation of new procedures. Computer support improves the quality of data analysis and allows for the application of new methods and models.
A time‐series approach to discrete real‐time process quality control
Authors: Yourstone Steven A. , Montgomery Douglas C. 
Published: July 2007

AbstractStatistical process control methods are usually applied in an environment when periodic sampling and rational subgrouping of process output is appropriate. The resulting summary statistics can be graphically displayed and analysed using either traditional Shewhart control charts or other charts such as those based on the cumulative sum. This article presents an alternative approach, based on time series analysis of all the real‐time process data. The time series approach is employed because the sequence of process observations may not be statistically independent. The autocorrelative structure in the data may be captured using an ARIMA model, and the residuals from this model are shown to be an effective input signal for a variety of statistical process control procedures.
On a linearized model and adaptive controller implementation for manipulator motion
Authors: Guo T. H. , Koivo A. J. 
Published: July 2007

AbstractThe detailed model for the motion of a manipulator system is linearized along a specific path. An on‐line parameter estimation algorithm based on the least‐squares criterion is used to determine the parameter values along the path at the operating instances. Based on the estimated parameter values, a self‐tuning adaptive controller is designed by minimizing a chosen performance criterion. Simulation results as well as experimental results are presented to demonstrate the approach. Certain aspects of the implementation are discussed.