Tensile Stress Relaxation of Alumina at High Temperature

The development of a tensile testing methodology for ceramics which enables a stress vs strain-rate response to be measured at high temperature is described. The test involves a carefully controled stress relaxation test at constant total strain using an experimental procedure and phenomenological analysis previously developed for metallic materials. It is demonstrated here with preliminary tests on alumina at 1050° and 1150°C. This offers, with further development, the possibility of establishing design stresses associated with low strain-rate behavior for structural applications. The results demonstrate that data covering four decades of strain rate may be generated in tests lasting a few hours. The inelastic strain consists of substantial anelastic recoverable strain in addition to a permanent creep strain.     

Novel water sorption behavior of emulsion blends

As waterborne emulsions continue to replace their solvent‐based counterparts in various applications, the water resistance of cast films is attracting significant interest. The characterization of the water sorption kinetics and structure–property relationships related to water sorption is, therefore, an important area for investigation. In this study, the water sorption kinetics of emulsion blends were compared with those of their blend components. The investigated blends were at equal weight (dry basis) fractions for each emulsion. The initial water sorption rate for immiscible emulsion blends was found to be significantly higher than composite values of the constituents. This behavior was due to percolation networks in the blends because thermodynamic constraints prevented diffusion across the interface bordering dissimilar particles, leaving a interface enriched with water‐sensitive species. The peak water sorption for the immiscible emulsion blends was lower than the composite values because of the ability of the water‐sensitive species to rapidly diffuse out of the samples due to the percolation network. This behavior existed for room‐temperature‐cast samples and persisted as the time and temperature exposure was increased. Atomic force microscopy results clearly showed the potential for percolation networks in the blends. Higher glass‐transition emulsion polymers [e.g., poly(vinyl acetate)] exhibited similar behavior, and this indicated poor film formation like that for the immiscible emulsion blends. These results indicated that the degree of film formation was critical with respect to the water sorption characteristics of emulsion films. Immiscible emulsion blends were compared with miscible emulsion blends for which all constituents exhibited excellent film formation (unblended). The immiscible blends exhibited a significant difference in water sorption compared with the miscible blends because of the existence of percolation networks. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 933–939, 2003     

Paging tradeoffs in distributed-shared-memory multiprocessors

Massively parallel processors have begun using commodity operating systems that support demand-paged virtual memory. To evaluate the utility of virtual memory, we measured the behavior of seven shared-memory parallel application programs on a simulated distributed-shared-memory machine. Our results (1) confirm the importance of gang CPU scheduling, (2) show that a page-faulting processor should spin rather than invoke a parallel context switch, (3) show that our parallel programs frequently touch most of their data, and (4) indicate that memory, not just CPUs, must be gang scheduled. Overall, our experiments demonstrate that demand paging has limited value on current parallel machines because of the applications' synchronization and memory reference patterns and the machines' high page-fault and parallel context-switch overheads.An earlier version of this paper was presented at Supercomputing '94.This work is supported in part by NSF Presidential Young Investigator Award CCR-9157366; NSF Grants MIP-9225097, CCR-9100968, and CDA-9024618; Office of Naval Research Grant N00014-89-J-1222; Department of Energy Grant DE-FG02-93ER25176; and donations from Thinking Machines Corporation, Xerox Corporation, and Digital Equipment Corporation.     

Radiation-Chemical Resistance of Anion Exchangers and Safety of Sorption Processes in Nitric Acid Solutions: III. Radiation-Chemical Resistance of VP-1AP Anion Exchanger

Variation of physicochemical characteristics of VP-1AP anion-exchange resin in HNO₃ solutions on heating and under the action of external -radiation up to the absorbed dose of 5 MGy was studied. It was shown that at thermal treatment of anion exchanger with increasing HNO₃ concentration and temperature and under the action of ionizing radiation the total exchange capacity (TEC) and capacity with respect to strongly basic groups (C _{s b g}) decrease. The swelling coefficients K _{s w} noticeably vary only in treatment in 12 M HNO₃ solutions and reach a maximum of 1.4. In this case, the specific surface area of the sorbent decreases from 15.7 to 1.2 m² g^{- 1}. Under the action of ionizing radiation the specific surface area of the irradiated anion exchanger somewhat increases and reaches 18 m² g^{- 1}.     

The burden of injuries in the Philippines: implications for national research policy

Injuries cause 10% of the mortality and 15% of disability worldwide. However, there is a paucity of data on injuries in the developing world where two-thirds of all injury deaths occur. This is the first published report characterizing the overall problem of injuries in the Philippines, a developing country in southeast Asia. This report defines the burden of injuries in the Philippines and identifies priority areas for the national health research agenda. A systematic review of 35 years of published and unpublished data on injuries in the Philippines (1960–1995) was conducted. Injury fatality rates increased by 196% from 14.3 per 100,000 in 1960 to 42.3 per 100,000 in 1995, and one in 11 deaths in the Philippines are due to injuries. Intentional injuries account for 48% of all injury deaths and motor vehicle crashes for 15%. For 15–44 year old males, injuries account for 42% of all deaths, 67% of which are intentional. The proportion of all deaths attributable to intentional injuries has increased by 925% and that of motor vehicle crashes by 600% from 1960 to 1995. Improvements in injury surveillance and documentation of non-fatal injury outcomes are needed. Research into risk factors and potential interventions for the prevention of intentional injuries should be a priority in the Philippines.     

Modeling of notch tensile behavior of martensitic steels

Notch tensile tests have been carried out on six grades of a high-strength martensitic steel at different hardness levels to investigate the effects of stress triaxiality at the net section and uniaxial tensile properties on fracture behavior. Cylindrical V-notched specimens were used in these tests with the notch-root radius, ρ, ranging from 0.03–1.4 mm, and with the value of the net-to-gross diameter ratio being 0.6. The notch strength ratio (NSR) was found to attain its maximum value at ρ=0.38 mm. The test results were used successfully for screening the fracture toughness behavior of the martensitic steel by extrapolating the corresponding ρ-NSR curve to ρ=0.0. Further, finite element computation of the average stress triaxiality factor ( ) enabled the development of a model more accurate than that reported in the literature for estimating NSR for a ductile material as a function of and its uniaxial tensile properties.     

Relationship between physicochemical properties and maximum residue levels and tolerances of crop-protection products for crops set by the USA, European Union and Codex

Residues on foodstuffs resulting from the use of crop-protection products are a function of many factors, e.g. environmental conditions, dissipation and application rate, some of which are linked to the physicochemical properties of the active ingredients. Residue limits (maximum residue levels (MRLs) and tolerances) of fungicides, herbicides and insecticides set by different regulatory authorities are compared, and the relationship between physicochemical properties of the active ingredients and residue limits are explored. This was carried out using simple summary statistics and artificial neural networks. US tolerances tended to be higher than European Union MRLs. Generally, fungicides had the highest residue limits followed by insecticides and herbicides. Physicochemical properties (e.g. aromatic proportion, non-carbon proportion and water solubility) and crop type explained up to 50% of the variation in residue limits. This suggests that physicochemical properties of the active ingredients may control important aspects of the processes leading to residues.     

Entropy analysis of conjugate heating in a pipe flow

In the present study, an analytical approach governing the temperature rise in the solid pipe and fluid is presented. The entropy analysis in the fluid system due to heat transfer is introduced to obtain the integrated entropy generation in the system. Coolanol, water and mercury are selected as fluids while copper and steel are considered as pipe materials. In order to simplify the analysis, the heat transfer coefficient at solid–liquid interface is kept constant during the calculations. It is found that the fluid temperature rise in the early heating period and the integrated entropy generation in the fluid system is lower in the case of a copper pipe. Copyright © 2002 John Wiley & Sons, Ltd.     

Web Support System for Business Intelligence in Small and Medium Enterprises

Last decade belongs to business intelligence (BI) because it is one of the few concepts that have actually lived to the expectations. Not only the businesses have adopted it but also have reaped the fruits out of it. But the cost of BI solutions is very high and has restricted small and medium enterprises to use BI solutions. The human resource is also limited and resultantly expensive in this field. This research proposes a web support system for business intelligence which provides automated data mapping and loading from user application to BI framework and also validates it. The system also assists users in getting the outputs in terms of reports and dashboards. The implementation of the proposed framework demonstrates convenience of use and effective cost saving as it does not require any technical expertise. The beauty of this web support system is that all the steps are menu driven and any non-technical user can get hold of it easily.