EFFECTS OF SPECIFIED BLANK SIZE ON BODY WRINKLING DURING HYDRODYNAMIC DEEP DRAWING OF TAPERED RECTANGULAR BOX

1.~nonHydridapawhcdeepdrawing(HDD)belongstothefieldofsheetmetalfoeingandcanbeaPPliedinthefieldofautomotive,aerospace,drilitaryindustryetc.Ithasbeenrecognizedwidelyintheworld["'j.Fig.Ishowsitsprinciple:TheliqUidthatisfilledinthe~ngdiecavitywillbepressedwhenthepunchgoesdownsothattheeffectoffrictionkeepingandoverflowlubricatingcanbeformed,astherestilt,thefoeinglicitofsheetmetalwillbeimprovedareailvandthegualitVofthefinishedpartswillbeup~ed.BecauseofmanyadvantagesofHDDprocees,ithasbeenwidelys…     

Simulation of nitrogen dynamics and biomass production in winter wheat using the Danish simulation model DAISY

A dynamic simulation model for the soil plant system is described. The model includes a number of main modules, viz., a hydrological model including a submodel for soil water dynamics, a soil temperature model, a soil nitrogen model including a submodel for soil organic matter dynamics, and a crop model including a submodel for nitrogen uptake. The soil part of the model has a one-dimensional vertical structure. The soil profile is divided into layers on the basis of physical and chemical soil characteristics. The simulation model was used to simulate soil nitrogen dynamics and biomass production in winter wheat grown at two locations at various levels of nitrogen fertilization. The simulated results were compared to experimental data including concentration of inorganic nitrogen in soil, crop yield, and nitrogen accumulated in the aboveground part of the crop. Based on this validation it is concluded that the overall performance of the model is satisfactory although some minor adjustments of the model may prove to be necessary.     

In Situ EXAFS Study on the Chemical State of Arsenic Deposited on a NiMoP/Al2O3 Hydrotreating Catalyst

The chemical state of arsenic deposited on a NiMoP/Al₂O₃ hydrotreating catalyst exposed to ppb levels of arsenic over several years in a refinery reactor has been studied by in situ EXAFS. In the as-received As-NiMoP catalyst, arsenic is exclusively coordinated to oxygen atoms. Upon sulfiding the sample in 2%H₂S/2%H₂/96%He, the As atoms become surrounded by approximately two sulfur atoms. No evidence was found for Ni–As bond formation. A possible model for the As local environment is suggested on the basis of combined EXAFS results, STM data and FEFF8.0 simulations (program for ab initio calculations on multiple scattering XAFS and XANES). The FEFF8.0 simulations of the proposed model are in accord with the experimental data measured at the As K edge. In this model, an As atom is located at the edge of a hexagonally truncated Ni-MoS₂ slab and is blocking the active NiMoS site.     

Plasma desorption mass spectrometry, an analytical tool in protein engineering: characterization of modified insulins

Californium-252 plasma desorption mass spectrometry (PDMS) hasbeen employed for the characterization of a series of humaninsulin derivatives in order to evaluate the performance ofthis technique as an analytical tool in protein engineering.Several of the characterized modifications result in a 1 a.m.u.mass change. The precision in mass determination obtainableby PDMS analysis is not sufficient for unambiguous verificationof such modifications based on the molecular weight alone. Itis, however, possible to carry out in situ enzymatic digestionof the sample. Subsequent PDMS analysis will in most cases revealif the modification has been introduced as intended.     

Nitrate leaching from loamy soils as affected by crop rotation and nitrogen fertilizer application

Nitrate leaching as affected by cropping system/crop rotation, history of farmyard manure application or fertilizer nitrogen application (0 N, 0.5 N and 1 N) was studied at nine sites on loamy soils during 1986/87, 1987/88 and 1988/89. Soil solution from 80 to 90 cm soil depth was sampled every second week in the period November to May by the use of porous ceramic cups and analysed for NO₃-N and Cl. Climatical conditions were obtained from standard meteorological observations in the region. Drainage from soil profiles was calculated from measured and simulated values of precipitation and actual evapotranspiration, respectively.The results show that type of crop is of the utmost importance for the leaching magnitude of nitrate as 40% of the total variance in nitrate concentrations in the soil solution could be explained by the type of crop.The second factor of importance was the history of farmyard manure (FYM) application, which was able to explain 28% of the total variation in nitrate concentration in the soil solution. Nitrate concentration/leaching from arable land without FYM ever being applied was considerably lower than from arable land which received periodical FYM applications until the early 70's or from arable land which besides periodical FYM applications in the past presently still receives regular applications of FYM. Only about 1% of the total variation in nitrate concentration in the soil solution was explainable by the level of fertilizer nitrogen application.Differences between years explained 14% of the total variation in nitrate concentration in the soil solution due to differences between the years in soil temperatures and water run-off. The run-off during the autumn and winter of 1986/87, 1987/88 and 1988/89 was 95, 275 and 55 mm, respectively. As expected nitrate leaching increased with increasing run off. However, nitrate leaching at the 275 mm run off was considerably lower than expected, which seems explainable by a substantial denitrification. The soil at the sites in question seems thus partly to purify the soil solution for nitrate before it leaves the root zone at the observed high run off conditions.     

Structuration bridging diffusion of innovations and gender relations theories: a case of paradigmatic pluralism in IS research

This paper discusses the adoption of a pluralist theoretical framework – one that is also multiparadigmatic – for conducting and publishing information system (IS) research. The discussion is illustrated by a single case study involving the Australian cotton industry. The theoretical framework is informed by three sociological theories, each with its particular paradigmatic assumptions: structuration theory as a meta‐theory, and diffusion of innovations and gender relations as lower‐level theories from notionally opposing paradigms. Theoretical pluralism helped to produce rich findings, illuminating both the social nature of women farmers' roles, the materiality of the cotton farming context, the characteristics of the decision support systems in use and the recursive way in which human agency and institutional pressures shape each other. Because users of so‐called divergent paradigms often face criticism based on the incommensurability issue, one of the main contributions of this paper is to discuss the value of a pluralist and multiparadigmatic theoretical framework in dealing with complex IS social phenomena.     

A simple chromatographic method for purification of egg lecithin

Egg lecithin was purified from the CdCl₂-lecithin complex by column chromatography on Alumina. The yield from 5 eggs was 2.8 g. The purified lecithin had correct chemical values for pure lecithin and a fatty acid composition similar to lecithin prepared by other methods. The method probably can be adapted for purification of other lipids containing the phosphocholine moiety and for purification of synthetic lecithin.     

Hydrocarbon synthesis over sulfide catalysts. Break-down of the Anderson-Schulz-Flory distribution

The kinetics of hydrocarbon synthesis over sulfide-based catalysts was studied. It appears that the formation of methane follows another reaction path than that of higher hydrocarbons. This might explain the very high selectivities for ethane and propane as compared with conventional Fischer-Tropsch catalysts. Reference is made to testing of the catalysts at industrial conditions.     

板金液压柔性技术及其产品设计

板金液压柔性成形具有诸多的优点,受到了汽车、航空航天等领域设计和研究者的普遍重视。文章主要介绍了板金液压柔性成形技术的内涵和外延,针对所提出的无模液压柔性成形技术和复合液压柔性成形技术,从不同的工艺方法入手,基于所研制的液压柔性成形设备,介绍了相关的飞机等领域产品特点以及设计要点,并对其中的关键工艺参数进行了描述。