Sensitivity study of BP-KX and B3 creep and shrinkage models

A numerical study of sensitivity analysis and statistical prediction of concrete creep average compliance function and shrinkage strain is presented. Two advanced models—the BP-KX and the B3—are studied. The influence of uncertainty of the basic input variables is taken into account by considering them as random variables. The statistical correlation is also treated in a simplified form for the assessment of its influence. Utilising the numerical simulation Latin Hypercube Sampling, the statistical and sensitivity analyses are performed. The results using different models are also compared. Two alternative measures of sensitivity analysis are utilised: sensitivity in terms of coefficient of variation and sensitivity in terms of nonparametric rank-order correlation coefficient. The strength of concrete and humidity appear as the most dominant factors with regard to the variability of results. Also, the estimations of distribution functions of the models are shown. They provide the possibility of establishing appropriate confidence limits. The significant difference in their ranges for the models in question is also shown.     

Modeling the positive-feedback regenerative process of CMOS latchupby a positive transient pole method. I. theoretical derivation

A novel method to characterize the mechanism of positive-feedback regeneration in a p-n-p-n structure during CMOS latchup transition is developed. It is based on the derived time-varying transient poles in large-signal base-emitter voltages of the lumped equivalent circuit of a p-n-p-n structure. Through calculating the time-varying transient poles during CMOS latchup transition, if is found that there exists a transient pole to change from negative to positive and then this pole changes to negative again. A p-n-p-n structure, which has a stronger positive-feedback regeneration during turn-on transition, will lead to a larger positive transient pole. The time when the positive transient pole occurs during CMOS latchup transition is the time when the positive-feedback regeneration starts. By this positive transient pole, the positive-feedback regenerative process of CMOS latchup can be quantitatively characterized     

Dependence on the pump frequency of the sensitivity of the rf SQUID

Numerical simulation techniques are used to investigate the frequency dependence of the noise of the hysteretic rf SQUID up to frequencies on the order ofR/L. An exact lower bound for the noise of the instrument is given as a function of the parameters of the SQUID ring, pump frequency, and the temperature. This result is compared with the predictions of a scaling argument and with experiment.     

New antithrombotic agents

The wide range of compounds currently being developed is the result of the continuing need for validated new antithrombotic agents. The prevention and treatment of venous thrombosis is predominated by anticoagulants: low molecular weight heparins, and potentially new antithrombin agents including hirudin. The effectiveness of new antiplatelet agents, and particularly c7E3 and integrelin, confirms the hypothesis concerning the role played by platelets in thrombogenesis in coronary arteries. But, due to the proaggregating effect of thrombin, anticoagulants could also have an important role in preventing arterial clots, either when given alone or in combination. Finally, the development of antithrombin and anti-platelet-glycoprotein IIb IIIa given orally is one of the major objectives of current research. Until the ideal antithrombotic agent is discovered, multiple-drug regimens combining anticoagulants and/or antiplatelet agents could be proposed in patients with a very high risk of thrombosis. Such regimens must taken into account the increased risk of bleeding and be adapted on the basis of careful laboratory surveillance.     

A new on-chip ESD protection circuit with dual parasitic SCRstructures for CMOS VLSI

A new CMOS on-chip electrostatic discharge (ESD) protection circuit which consists of dual parasitic SCR structures is proposed and investigated. Experimental results show that with a small layout area of 8800 μ², the protection circuit can successfully perform negative and positive ESD protection with failure thresholds greater than ±1 and ±10 kV in machine-mode (MM) and human-body-mode (HBM) testing, respectively. The low ESD trigger voltages in both SCRs can be readily achieved through proper circuit design and without involving device or junction breakdown. The input capacitance of the proposed protection circuit is very low and no diffusion resistor between I/O pad and internal circuits is required, so it is suitable for high-speed applications. Moreover, this ESD protection circuit is fully process compatible with CMOS technologies     

Sterically inhomogenous viscoelastic behavior of human saccular cerebral aneurysms

To clarify the mechanism leading to the development and rupture of intracranial aneurysms, tensile strength and viscoelastic parameters of 22 human saccular aneurysms were investigated. Meridional and circumferential strips from the thin and the thick part of the aneurysm sack and 18 control strips from the basilar artery of 8 patients with pathologies not affecting the cerebral arterial system were studied. The length of the strips was increased in 200- microm steps, while distending force was recorded. Tensile strength and viscoelastic parameters were computed. In both directions, tensile strength of thick strips was significantly lower than that of controls. In the meridional direction, tensile strength of thin strips was significantly larger than that of thick ones (14.5 +/- 4.1 x 10(6) vs. 7.5 +/- 2.0 x 10(6) dyn/cm2, p < 0.05). In the circumferential direction, thin strips tore at lower strain values than thick ones (29 +/- 4 vs. 55 +/- 16%, p < 0.05). Viscoelastic parameters changed in parallel. In circumferential direction, values of thick and thin strips were significantly lower than those of controls. In the meridional direction, values of thin strips were significantly higher than those of the thick ones. These observations show that characteristic mechanical deterioration and steric inhomogeneities accompany the loss of smooth muscle cells and the derangement of connective tissue elements in the wall of intracranial aneurysms, which may explain certain steps in their initiation, enlargement and rupture.     

Efficient measurement procedures for compound part profile by computer vision

It is apparent that automated inspection for manufacturing is on the threshold of broad industrial utilization. One key problem in manufacturing applications of automated inspection is how to find fast and efficient methods using economical computers that industry can afford. Moreover, most mechanical designers set only overall tolerances for part geometric features. In computer vision inspection, as well as in the use of other automated inspection devices and coordinate measuring machines (CMM) the errors of representing each geometric features should be identified separately. The proposed statistical inference method provides a scientific basis for setting inspection tolerances in original geometric space which are compatible with engineering specifications.

The results of this presentation should supply industrial practitioners with an accurate and fast approach for on-line part profile inspection.     

Computerized continuous monitoring and analysis of ozone in solution

This paper presents a method for continuous monitoring of ozone in water by using the Indigo colorimetric technique. The details of an instrument developed and used for this purpose are explained. Data obtained using the continuous ozone reading equipment in monitoring the ozone levels are presented. The instrument also can be used to measure the decay of ozone in ozonated waters, continuously giving a very accurate measure of ozone decay coefficients.     

Lateral SCR devices with low-voltage high-current triggeringcharacteristics for output ESD protection in submicron CMOS technology

A high-current PMOS-trigger lateral SCR (HIPTSCR) device and a high-current NMOS-trigger lateral SCR (HINTSCR) device with a lower trigger voltage but a higher trigger current are proposed to improve ESD robustness of CMOS output buffer in submicron CMOS technology. The lower trigger voltage is achieved by inserting short-channel thin-oxide PMOS or NMOS devices into the lateral SCR structures. The higher trigger current is achieved by inserting the bypass diodes into the structures of the HIPTSCR and HINTSCR devices. These HIPTSCR and HINTSCR devices have a lower trigger voltage to effectively protect the output transistors in the ESD-stress conditions, but they also have a higher trigger current to avoid the unexpected triggering due to the electrical noise on the output pad when the CMOS ICs are in the normal operating conditions. Experimental results have verified that the trigger current of the proposed HIPTSCR (HINTSCR) is increased up to 225.5 mA (218.5 mA). But, the trigger voltage of the HIPTSCR (HINTSCR) remains at a lower value of 13.4 V (11.6 V). The noise margin against the overshooting (undershooting) voltage pulse on the output pad, without accidentally triggering on the HINTSCR (HIPTSCR), can be greater than VDD+12 V (VSS -12 V). These HIPTSCR and HINTSCR devices have been practically used to protect CMOS output buffers with a 4000-V (700-V) HEM (MM) ESD robustness but only within a small layout area of 37.6×60 μm² in a standard 0.6-μm CMOS technology without extra process modification