Stress Testing

The effect of layer structure (GaN versus AlGaN cap) and cleaning procedure prior to Sc2O3 or MgO deposition at 100° C were examined for their effects on the long-term bias-stress stability of AlGaN/GaN high electron mobility transistors (HEMTs). Surface cleaning by ...

The present research work describes comprehensive stress testing of eprosartan mesylate (EM) according to ICH guideline Q1A (R2), and development of a stability-indicating reversed phase ultra performance liquid chromatographic (UPLC) assay. The drug was ...

: Qualitative accelerated test methods improve system reliability by identifying and removing initial design flaws. However, schedule and cost constraints often preclude sufficient testing to generate a meaningful reliability estimate from the data obtained in these tests. In this dissertation a modified accelerated life test is proposed to assess the likelihood of attaining a reliability requirement based on tests of early system prototypes. Assuming each prototype contains an unknown number of independent competing failure modes whose respective times to occurrence are governed by a distinct Weibull law, the observed failure data from this qualitative test are shown to follow a poly-Weibull distribution. However, using an agent-based Monte Carlo simulation, it is shown that for typical products subjected to qualitative testing, the failure observations result from a homogenous subset of the total number of latent failure modes and the failure data can be adequately modeled with a ...

To assess the effects of a single 100-mg dose of sildenafil citrate on visual function in men with early-stage age-related macular degeneration. Randomized double-blind placebo-controlled clinical trial. Nine men (mean age 71 years, range 59-85 years) with early-stage (minimal visual impairment and large drusen in the macula) age-related macular degeneration and 20/40 or better-corrected visual acuity in at least one eye were prospectively randomized to receive either placebo or sildenafil citrate (Viagra; Pfizer Inc, New York, New York) 100 mg as a single oral dose. After 7-14 days, they received the alternate treatment. Subjects underwent visual acuity, Amsler grid, color discrimination (D15), traffic light, Humphrey perimetry, and photo-stress testing in each eye before and at specific intervals within 8 hours after dosing. Compared with placebo, no pattern of errors were evident in any visual function test following sildenafil administration. No statistically or clinically relevant changes from baseline were observed in visual acuity, Humphrey perimetry (corrected pattern standard deviation), D15 color discrimination, or photo-stress tests. No clinically relevant changes were observed in the Amsler grid or traffic light tests. Sildenafil treatment was associated with transient mild or moderate headache, flushing, and rhinitis. There were no visual adverse events spontaneously reported to the investigator. A single 100-mg dose of sildenafil was well tolerated and produced no acute visual effects or exacerbation of preexisting visual impairment in nine men with early-stage age-related macular degeneration.

The aim of this study is to present the new architecture of the European financial supervision the necessity of which had been brought into sharp focus by its deficiencies in the current financial crisis. The study presents through the prism of the report edited by the de Larosiere Group the main generating elements of the financial crisis, the deficiencies of the risk management, of corporate governance regulations, the lack in applying the regulation framework and in supervision regarding risk management.

This paper presents the findings of work performed on 20-μm diameter copper wire of five different wire types from three suppliers. Gold wire is the control. The test die was mounted on BT (B (Bismaleimide) and T (Triazine)) resin substrates. The bonding parameters were optimized for each wire used. Part of the optimization process involved monitoring the flatness of the bonded ball and the amount of aluminum remaining under the bond. The crystal structure of each type of interconnect was examined using composite imaging techniques. Visual data such as ball size, thickness, and shape were collected. First and second bonds were subjected to destructive testing, such as ball shear and wire pull, throughout the preparation process. The samples were then subjected to an industry-standard, high temperature stress test to determine the long-term stability of the interface of each wire type. Data for all read points are presented on all tests performed and provide useful information on the...

The need to focus on banks’ funding structure and stress testing in an explicit way arose as a consequence of the crisis of past decades. Liquidity risks usually occur as a consequence of other kinds of risks, hence analysing scenarios in a prospective manner is essential for the assessment if the bank can fulfill its obligations as they come due and if its funding costs are appropriate. The structural liquidity risk and the degree of the liquidity mismatch can be measured based on the liquidity gap analysis, where expected cash-in- and outflows, divided in different
time-buckets are depicted. The liquidity gap report (LGR) shows if a liquidity shortcoming appears in the future and how high is the amount a bank would have to pay, if any hedging were not possible. This paper shows how to build a comprehensive LGR which is the base for both, liquidity and wealth risk evaluation. To improve the accuracy of the forecast, the counterbalancing capacity will be incorporated into the LGR. This tool is a methodological basis for quantitative and qualitative risk assessment and stress testing.

There are several models for the calculation of the acceleration factor for the electronic assemblies subjected to stress tests. A correct reliability assessment requires an accurate analysis of these models and the evaluation of their real effectiveness and adequacy. As regard to the solder joints subjected to the thermomechanical stresses given by temperature variation, applicable models are the original Coffin-Manson model, the Coffin-Manson model modified by Norris and Landzberg, and the model described in the standard IPC-SM-785. The last one is the most complete model to evaluate the acceleration factors given by slow temperature swings. However, the most effective method for the estimate of the solder joint aging is based on the analysis of the microstructure of the alloy. Regarding the acceleration factors of the electronic components, the international standard IEC 61709 can be used. This standard provides the equations to determine the intrinsic failure rates of the electronic components. Those equations allow to calculate the acceleration factors for the different types of stress (caused by temperature, voltage, current, etc.). This standard is more linked to the actual characteristics of the components than MIL-STD-217F, which was widespread in the past. IEC 61709 is also a useful tool for the design of electronic assemblies. A new method for the calculation of the acceleration factors is the analysis of the variation of the electrical parameters of the assembly when the stress is applied. This new method allows to evaluate directly the effects of the stress on the functionality of the assembly.

Description/Abstract This manual focuses on the needs of engineers involved in the geotechnical design of foundations for transmission line structures. It also will serve as a useful reference for other geotechnical problems. In all foundation design, it is necessary ...