Predicting the steady state thickness of passive films in order to prevent degradations of implant

Some implants have approximately a lifetime of 15 years. The femoral stem, for example, should be made of 316L/316LN stainless steel. Fretting corrosion, friction under small displacements, should occur during human gait, due to repeated loadings and un-loadings, between stainless steel and bone for instance. Some experimental investigations of fretting corrosion have been practiced. As well known, metallic alloys and especially stainless steels are covered with a passive film that prevents from the corrosion and degradation. This passive layer of few nanometers, at ambient temperature, is the key of our civilization according to some authors. This work is dedicated to predict the passive layer thicknesses of stainless steel under fretting corrosion with a specific emphasis on the role of proteins. The model is based on the Point Defect Model (micro scale) and an update of the model on the friction process (micro-macro scale). Genetic algorithm was used for finding solution of the problem. The major results are, as expected from experimental results, albumin prevents from degradation at the lowest concentration of chlorides; an incubation time is necessary for degrading the passive film; under fretting corrosion and high concentration of chlorides the passive behavior is annihilated

Computerized crime linkage systems: A critical review and research agenda

Computerized crime linkage systems are meant to assist the police in determining whether crimes have been committed by the same offender. In this article, the authors assess these systems critically and identify four assumptions that affect the effectiveness of these systems. These assumptions are that (a) data in the systems can be coded reliably, (b) data in the systems are accurate, (c) violent serial offenders exhibit consistent but distinctive patterns of behavior, and (d) analysts have the ability to use the data in the systems to link crimes accurately. The authors argue that there is no compelling empirical support for any of the four assumptions, and they outline a research agenda for testing each assumption. Until evidence supporting these assumptions becomes available, the value of linkage systems will remain open to debate

Tax - Dependency Deductions for Paramours

In adhering to a constitutionally derived recognition of the states within the federal system, Congress has consistently deferred to the states in the regulation of marriage, family life and domestic affairs. In the application of the federal tax laws, Congress has demonstrated its respect for the individual states by the enactment of § 152(b)(5) of the Internal Revenue Code. This 1958 enactment denies a taxpayer an exemption for a dependent if the relationship between the claimed dependent and the taxpayer violates local law. In Ensminger v. Commissioner the United States Court of Appeals for the Fourth Circuit upheld a decision by the Commissioner of Internal Revenue that denied a dependency exemption for a live-in lover, because the relationship between the North Carolina taxpayer and his claimed dependent violated state law. This note will review the decision in Ensminger and will explore its implications

Tax - Dependency Deductions for Paramours

In adhering to a constitutionally derived recognition of the states within the federal system, Congress has consistently deferred to the states in the regulation of marriage, family life and domestic affairs. In the application of the federal tax laws, Congress has demonstrated its respect for the individual states by the enactment of § 152(b)(5) of the Internal Revenue Code. This 1958 enactment denies a taxpayer an exemption for a dependent if the relationship between the claimed dependent and the taxpayer violates local law. In Ensminger v. Commissioner the United States Court of Appeals for the Fourth Circuit upheld a decision by the Commissioner of Internal Revenue that denied a dependency exemption for a live-in lover, because the relationship between the North Carolina taxpayer and his claimed dependent violated state law. This note will review the decision in Ensminger and will explore its implications

The history and effects of alien plant control in the Cape of Good Hope Nature Reserve, 1941–1987

Concern about the invasion of this reserve by alien trees and shrubs, principally Acacia cyclops, A. saligna, A. longifolia, Eucalyptus lehmannii and Pinus pinaster, was first expressed in 1941, 2years after its proclamation. Control operations were started by 1943 and were almost totally ineffective for at least the first 35years; no systematic control strategy was implemented, follow-up control work was inadequate to prevent reestablishment of felled thickets and the supervision of control teams was deficient. Linkage of control operations to firewood production was a significant factor in this failure. In 1974 a 10-year control strategy was drawn up and in the late 1970’s began to be effectively implemented. Surveys of 40 plots in the centre of the reserve in 1966, 1976–80 and 1986 showed increasing densities of species other than the easily controlled P. pinaster up to 1976–80. Since then almost all individuals>1,8m in height have been eliminated and indications from smaller height classes are that seed banks are being depleted. Explanations are advanced for the successes and failures experienced during the 47years of control. Some of the side-effects of these invasions and their control are discussed. One conclusion is that this reserve requires a qualified ecologist on its staff

The alien flora of the Cape of Good Hope Nature Reserve

An annotated species list of the alien vascular plant flora of the Cape of Good Hope Nature Reserve is presented. The flora comprises five gymnosperm and 68 angiosperm species that are definitely alien to the reserve and four angiosperm species that are possibly alien. The life-form distribution of the alien flora is shown to be significantly different from that of the indigenous flora; trees, shrubs and annual herbs are more important in the alien flora, and dwarf shrubs and perennial herbs are much less important. Biotic factors are suggested as being important in determining the success of alien invasions, in particular grazing by ungulates. The invasion rate is currently about one new species per year. By ceasing to introduce tree species and by restricting human disturbance, the rate of invasion of new species could be reduced

Mechanical Properties of Stainless Steel Lipped Channels

This paper describes and discusses the results obtained from a series of tensile tests performed on cold formed stainless steel Type 304 members of lipped channel cross-section. Standard tensile tests on coupons cut from the webs of the sections were carried out, as were full section tensile tests. Ramberg-Osgood type curves based on the procedure suggested in the ASCE design code were fitted to the stress-strain results and these are compared with the experimental results and Ramberg-Osgood type curves derived on an alternative basis

Compressional Behaviour of Stainless Steel Short Struts

The effects of cold forming on both carbon steel and stainless steel structural members has been the subject of extensive research since the early 1940\u27s. Design code specifications for carbon steel members have been published in many countries around the world, including BS 5950, Part 5 in the UK (1) the AlSI Specification in the USA (2), and the new Eurocode 3, Part 1.3 (3). For stainless steel members there are fewer design code specifications available, and those that are available, which include the ANSI/ASCE in the USA (4) and the new Eurocode 3, Part 1.4 (5), do not give such detailed design recommendations as the carbon steel specifications. This paper describes the results obtained from a series of axial compression tests performed on short strut members of plain channel cross section cold formed from Type 304 stainless steel sheet. The comer radius and the material thickness are varied to examine the effects of cold forming on the load capacity of the channels in compression and the results are compared to those obtained from the relevant design specifications. Conclusions are drawn on the basis of the comparisons