Temperature effects on the mass flow rate in the SBI and similar heat‐release rate test equipment

In various medium‐to‐large‐scale fire test equipments like the ISO room corner test (RC), and more recently, the single burning item test (SBI) the mass flow rate measurement of the combustion gases plays a key role in the determination of the heat‐release rate and smoke‐production rate. With the knowledge of the velocity profile and the temperature of the flow, the mass flow rate is obtained by measuring the velocity on the axis of the duct. This is done by means of a bi‐directional probe based on the pitot principle. However, due to the variation of the mean temperature and the temperature gradient in any cross section of the duct, introduced by ever changing combustion gas temperatures, the velocity nor the density profile are constant in time. This paper examines the resulting uncertainty on the mass flow rate. Copyright © 2006 John Wiley & Sons, Ltd.     

Progress toward roll-to-roll processing of inorganic monolithic electrochromic devices on polymeric substrates

As electrochromic device (ECD) emerges into the market, the necessity of cost reduction via high-throughput manufacturing is unavoidable. Inorganic monolithic ECD has compatibility in its manufacturing steps, allows continuous processing and hence low-cost ECD. A roll-to-roll (R2R) production is the industrial standard for high-throughput processing and was chosen to synthesize ECD on polymeric substrates. Preliminary success by implementing methods compatible to the aforementioned R2R processing has been achieved; however, continuous test-runs on an R2R machine are still limited.     

Numerical investigation of the error on flow measurements due to exhaust gas heating and cooling in the SBI‐configuration

The possible flow measurement error due to heating or cooling of exhaust gases in the Single‐Burning‐Item (SBI) test is estimated from numerical experiments. It is illustrated that there is no one‐to‐one correspondence between the velocity profile shape and the instantaneous Reynolds number, due to the time‐dependent temperature and density profile evolution in the exhaust gas pipe. A non‐ambiguous relation is found between the velocity profile shape and an ‘effective’ Reynolds number, based on the turbulent viscosity. Maximum variations of the velocity correction factors, relating the mean velocity to the velocity on the pipe axis, are found to be in the order of 2% for limiting circumstances for the SBI test. The primary effect is caused by instantaneous Reynolds number variations. The effect of heating or cooling of the flow by the hot or cold pipe is noticeable, too. The statements are proved to be valid independent of the computational grid, the turbulence model and the time steps taken to obtain the numerical solutions. Copyright © 2006 John Wiley & Sons, Ltd.     

MIMC reliability and electrical behavior defined by a physical layer property of the dielectric

Metal–insulator–metal capacitor (MIMC) reliability and electrical properties are defined by the TDDB lifetime, breakdown voltage and leakage current. In this article, the correlation is determined between these electrical properties and the physical and chemical properties of the SiN dielectric layer. It is demonstrated how a SiN dielectrics with a high refractive index have high Si content and show an increased initial leakage current. However, contradictory to the high leakage current, these dielectrics also show high lifetimes. It is shown that SiN dielectrics with a high Si content contain high numbers of charge trapping centers. Over time, a high concentration of trapped charges is build up to such an extend that the local electric field over the dielectric is significantly decreased. This results in the observed reliability improvement of the dielectric. The final intrinsic quality and reliability of MIMC capacitors can therefore be determined by measurable physical properties of the MIMC dielectric at the time of the deposition of this layer.     

Solder parameter sensitivity for CSP life-time prediction using simulation-based optimization method

Finite element modeling (FEM) is widely used for estimating the solder joint reliability of electronic packages. However, the solder properties are strongly process and geometry dependent. Even for the same type of solder, measurements conducted by different people at different locations show different results, due to differences in application conditions, benching etc. Those differences may lead to differences in constitutive equations and/or the parameter values. Therefore the effect of the solder parameter variation and parameter sensitivity should be taken into account before a reliable solder fatigue prediction can be made. In this research, a simulation based optimization method is used to investigate the sensitivity of the chosen solder parameters for the solder fatigue prediction using an inelastic strain criterion.     

Characterization and FE analysis on the shear test of electronic materials

Adhesion is one of the main reliability concerns in electronic packages. However, the lack of standards to characterize this property makes it difficult to interpret the results. In this work, a series of shear tests have been conducted to evaluate adhesion strength of different electronic materials.Finite element analysis (FEA) is employed here to model the shear strength of microelectronic materials and to analyze the stress distribution in the specimen and substrate in order to understand this failure mechanism. The shear tool force and displacement at failure were measured experimentally and used as boundary condition for the FEA calculations.Several combinations of soft and stiff materials for specimens and substrates respectively have been evaluated in order to estimate the effects on the shear strength. The general trend from experimental and FEM results shows that soft specimens present a high concentration of stresses in the loaded surface while in the case of rigid specimens, the stresses are distributed in the whole area of contact between specimen and substrate. A proposal for calculating the shear strength was done.     

Determinants of persistence in canine distemper viruses

The history of immunohistochemistry started in 1941 when Coons identified pneumococci using a direct fluorescent method. Then followed the indirect method, the addition of horseradish peroxidase, the peroxidase anti-peroxidase technique of 1979 and the use of the Avidin and Biotin complex in the early 1980s. This sequence of events can help one appreciate the differences in these various techniques and their increased sophistication and sensitivity. The technique has been applied in the field of safety evaluation of new pharmaceutical products. Examples of current projects are used to illustrate the scope of the application. The use of an antibody to detect proliferating cell nuclear antigen has, in a pilot study with the popliteal lymph node assay, provided a method of differentiating an irritant response to acetone from an immune response to hydrazine. In hydrazine-treated rats the proliferation is mainly in the follicular region whilst it is mainly sinusoidal in animals treated with acetone. In the guinea-pig maximisation test, initial work with dinitrochlorobenzene suggests that detection of Langerhans cells may aid the differentiation of an irritant from an immune response. The preclinical assessment of antibodies intended for therapeutic use in man requires immunohistochemistry to be used to identify any human tissues which show a cross-reactivity. The major problems are not in the test itself but in obtaining suitable material. Identification of hormones is a useful tool for assessing the effects of releasing factors and has proved useful in aiding tumour identification in routine carcinogenicity studies. In a rare case, detection of prolactin in cell deposits in the lungs of a rat confirmed that this was a metastasis from a pituitary carcinoma. The application of immunohistochemical techniques to preclinical assessment of drugs should always be considered. In particular, it is recommended that appropriate samples should be conserved from routine studies in order to permit these techniques to be performed, if considered appropriate in the light of findings during routine histological examination.     

A Novel Mechanism of Embrittlement Affecting the Impact Reliability of Tin-Based Lead-Free Solder Joints

This work addresses a new mode of brittle failure that occurs in the bulk of tin-based lead-free solder joints, unlike the typical brittle failures that occur in the interfacial intermetallics. Brittle failures in the joint bulk result from the low-temperature ductile-to-brittle transition in the fracture behavior of β-tin. The bulk embrittlement of these joints is discussed by referring to the results of impact tests performed on both solder joints and bulk solder specimens. The mechanism of bulk embrittlement is largely explained based on the results of a fractography study performed on the bulk joint failures using scanning electron microscopy.     

Calculation of no-load induction motor core losses using therate-dependent Preisach model

In this paper the authors present a two-step algorithm for predicting the core losses in an electrical machine. As a first step, the flux patterns in the cross section of the machine are calculated by using a time stepped two-dimensional finite element (FE) model, neglecting hysteresis and eddy currents in the laminated core. The second step consists in enforcing the calculated tooth and yoke flux waveforms to a one-dimensional FE lamination model in which the variation along the thickness of the induction and of the induced eddy currents is considered. The hysteretic behavior of the ferromagnetic material is taken into account by, means of a rate-dependent Preisach model. The outlined procedure is applied to a 3 kW squirrel-cage induction motor with either open or closed rotor slots, the former yielding elevated flux harmonics. Computation results and measurements at no-load (phase currents, stator tooth flux, and total iron losses) are compared