Quantification of severe accident source terms of a Westinghouse 3-loop plant

Integrated severe accident analysis codes are used to quantify the source terms of the representative sequences identified in PSA study. The characteristics of these source terms depend on the detail design of the plant and the accident scenario. A historical perspective of radioactive source term is provided. The grouping of radionuclides in different source terms or source term quantification tools based on TID-14844, NUREG-1465, and WASH-1400 is compared. The radionuclides release phenomena and models adopted in the integrated severe accident analysis codes of STCP and MAAP4 are described. In the present study, the severe accident source terms for risk quantification of Maanshan Nuclear Power Plant of Taiwan Power Company are quantified using MAAP 4.0.4 code. A methodology is developed to quantify the source terms of each source term category (STC) identified in the Level II PSA analysis of the plant. The characteristics of source terms obtained are compared with other source terms. The plant analyzed employs a Westinghouse designed 3-loop pressurized water reactor (PWR) with large dry containment.     

Simultaneous Analysis of Free/Bound Phytosterols and Diosgenin in Taiwanese Yams

Gas chromatography (GC) and high performance liquid chromatography (HPLC) methods were developed for the simultaneous analysis of phytosterols and diosgenin in two representative Taiwanese yams, Dioscorea pseudojaponica Yamamoto and Dioscorea alata L. The major phytosterols found were β-sitosterol, stigmasterol, and campesterol. GC afforded good separation of phytosterols and diosgenin, with the diosgenin peak appearing between stigmasterol and β-sitosterol. For HPLC, UV detection had higher sensitivity (detection limits 0.03–0.09 μg); however, evaporative light scattering detection (ELSD) achieved higher noise tolerance and did not show baseline interference from solvent gradients. In addition, mixed solvents for extraction before acid hydrolysis, which is necessary to avoid fibers and acid hydrolysates binding to the target compounds, were evaluated. Phytosterol contents of 30.1 and 9.9 mg/100 g were found in D. pseudojaponica Yamamoto and D. alata L., respectively. Diosgenin was only found in D. pseudojaponica Yamamoto at a content of 15.2 mg/100 g.     

pISRA: privacy considered information security risk assessment model

The Journal of Supercomputing - The security threats related to personally identifiable information are increasing dramatically. In addition to government agencies, large international companies...     

Discriminative effect of user influence and user responsibility on information system development processes and project management

Context

User participation in information system (IS) development has received much research attention. However, prior empirical research regarding the effect of user participation on IS success is inconclusive. This might be because previous studies overlook the effect of the particular components of user participation and other possible mediating factors.

Objective

The objective of this study is to empirically examine how user influence and user responsibility affect IS project performance. We inspect whether user influence and user responsibility improve the quality of the IS development process and in turn leads to project success, or if they have a direct positive influence on project success.

Method

We conducted a survey of 151 IS project managers in order to understand the impact of user influence and user responsibility on IS project performance. Regression analysis was conducted to assess the relationship among user influence, user responsibility, organizational technology learning, project control, user-developer interaction, and IS project management performance.

Results

This study shows that user responsibility and user influence have a positive effect on project performance through the promotion of IS development processes as mediators, including organizational technology learning, project control, and user-IS interaction.

Conclusion

Our results suggest that user responsibility and user influence respectively play an important role in indirectly and directly impacting project management performance. Results of the analysis imply that organizations and project managers should use both user participation and user influence to improve processes performance, and in turn, increase project success.     

Kinetic studies on electrochemical stripping of CrN films

Chromium nitride (CrN) films deposited on silicon substrates by a cathodic arc plasma technique were electrochemically stripped off in KOH alkaline electrolytes. Current densities and electrolyte concentrations were varied to investigate their influences on the stripping process. By analyzing the relation between the potential and reaction time, it is possible to determine the optimal time for terminating the stripping process because of the different resistivities of the substrates and overlayers. The critical stripping times were defined from the potential−time relation and were observed to be inversely proportional to the current density. The total required charge/unit volume was also determined. The relationship between the thickness of the residual films after stripping and the reaction time at various current densities and KOH concentrations was analyzed using a kinetic model. Moreover, CrN films deposited by another method, namely, unbalanced magnetron sputtering, were also tested for comparison. The stripping process was apparently influenced by the microstructure of the films.     

Effect of diameter variation in a large set of carbon nanotube transistors

A study involving a large number of carbon nanotube transistors reveals that the nanotube diameter and the metal contact material play key roles in determining the on- and off-state currents of these devices. The results are discussed in terms of the Schottky barrier at the metal-semiconductor junction and the variation of this barrier relative to the alignment of energy levels between the carbon nanotube and the metal.