Shrink-Fit Stress Systems in Built Crankshafts

Among applications of the well-known practice of shrink-fitting, the assembly of large marine crankshafts from relatively small forgings is perhaps the most outstanding example, having regard to the stringent operating conditions in which the component must function satisfactorily. Variations in shrink-fitting practice and failures attributable to slipping of the grip have directed attention to the lack of information on crankshaft assemblies and instigated an investigation, the results of which are presented in this thesis. A major part of the investigation comprises a survey of published literature relevant to the subject. It has been found that little is yet known about stress or grip conditions at the shrink-fit, and that the rules for sizes and proportions have evidently no theoretical foundation. The scope of the survey has therefore been extended to include work on all types of interference fits, from v/hich it is evident that, while a useful amount of empirical data on factors affecting grip strength exists, treatment of interface pressure and stress has been limited to the application of elastic thick cylinder theory. With a view to analysing stress conditions in assemblies overstrained by fit allowances which cause permanent enlargement of the hollow element, a part of the survey is devoted to examining work on thick cylinders subjected to internal fluid pressure. A number of features of shrink-fitting, such as prevention of free axial shrinkage, overstrain of the hollow element, and the influence of temperature on the elastic constants of the material, have been analysed as part of the theoretical work of the present investigation. On the basis of certain reasonable assumptions, a solution for the stress in a representative crank web shape has been obtained, using Relaxation Methods of analysis. Stress concentration and radial stiffness values, which correlate the complex shape to the rotationally-symmetrical, follow readily from the solution. The experimental investigations comprise tests on rings-and-plugs, on model crank webs, and on large crank webs removed from a vessel which had been scrapped. The results indicate that prevention of free axial shrinkage does, in fact, occur to a marked degree. Furthermore, the presence of axial grip has been detected in large crank webs which had suffered extensive cold-working due to pulsating bending actions during service. Model experiments have demonstrated the influence of surface finish on the grip strength to be quite unimportant. Friction values in the large crankshaft, on the mating surfaces of which tool-marks were clearly visible, were comparable with those in model webs with near-perfect honed surfaces. Interface pressure and stress values predicted from theoretical considerations were in sound agreement with values measured by electrical strain gauges and inferred from deformations. A list of design formulae and data, and recommendations for improvements to shrink-fitting practice, based on the results of the investigation, are presented

A Randomized Trial of a Multimodal Community-Based Prisoner Reentry Program Emphasizing Substance Abuse Treatment

Prisoner reentry programs continue to be developed and implemented to ease the process of transition into the community and to curtail fiscal pressures. This study describes and provides relapse and recidivism outcome findings related to a randomized trial evaluating a multimodal, community-based reentry program that prioritized substance abuse treatment. Results from analyses suggest negligible effects for participants of the program across multiple outcome indicators. Avenues for further exploration are provided, with a cautionary emphasis on the continued expansion of multimodal community-based reentry programs

Alternative models of instant drug testing: evidence from an experimental trial

Objective This study describes and provides relapse and recidivism outcome findings related to an experimental trial evaluating the viability of frequent, random drug testing with consequences for use. Methods The sample consisted of 529 offenders released on parole. An experimental design with random assignment to one of three groups was employed. The Experimental Group received frequent, random drug testing with instant results, immediate sanctions, and referral for substance abuse treatment. Control Group I received frequent, random drug testing and treatment referral, but did not receive immediate test results or immediate sanctions. Control Group II followed standard parole practice. Members of this group were not tested on a random basis and did not receive immediate sanctions. Repeated measures ANOVA and survival analysis techniques were used to explore group differences. Results Frequent monitoring of drug use with randomized testing protocols, immediate feedback, and certain consequences is effective in lowering rates of relapse and recidivism. The effectiveness is particularly salient in the short term during the period of exposure to testing conditions. Conclusions The findings lend support to the use of randomized testing with swift and certain sanctions with parolees. Additional quality evidence is necessary to generalize and refine findings from this study and others that focus on sanction certainty. Future replications must consider the immediacy of test result and sanction execution as well as the length of exposure to randomized testing periods

Survival of Northern Bobwhite Infected with Avian Pox

Avian pox is an enzootic disease among northern bobwhite (Colinus virginianus) in the southeastern United States, but occasionally it occurs as local or regional epizootics. Little information exists concerning survival of wild bobwhite infected with this disease. During the winters of 1985 and 1986, we compared survival of radio-tagged bobwhite with and without pox lesions. Pox lesions were considered wet or dry depending on field evaluations. The incidence of pox was greater in 1985 (x1=\u27 16.536, df= 1, P\u3c 0.005) than in 1986. Bobwhite with wet pox lesions weighed less than those with dry pox (t = 2.550, P = 0.014) or no pox (t = 2.393, P = 0.018). In 1985 6-week survivorship of bobwhite showing signs of wet pox was different compared to those with dry pox (Z = 1. 7 498, P = 0.0402) and no pox (Z = 2.9992, P = 0.0014). Survivorship of birds with dry pox and no pox was not different (Z = 0.6460, P = 0.2611. Bobwhite with wet pox in 1985 had 45.6 and 53.3% overall lower 6-week survival rates than birds with dry and no pox, respectively. No difference in survivorship existed between bobwhite with dry pox and those with no pox in 1986 (Z = 1.1727, P= 0.1210). No difference in predatory agents responsible for mortalities between birds with or without pox occurred (X2 = 0.8851, df= 2, P\u3e 0.05). All mortality of infected birds appeared to be caused by predation and not the disease itself. Implications of these data for inter- and intraspecific disease transmission are discussed

Comparative Genomics Identifies Candidate Genes for Infectious Salmon Anemia (ISA) Resistance in Atlantic Salmon (Salmo salar)

Infectious salmon anemia (ISA) has been described as the hoof and mouth disease of salmon farming. ISA is caused by a lethal and highly communicable virus, which can have a major impact on salmon aquaculture, as demonstrated by an outbreak in Chile in 2007. A quantitative trait locus (QTL) for ISA resistance has been mapped to three microsatellite markers on linkage group (LG) 8 (Chr 15) on the Atlantic salmon genetic map. We identified bacterial artificial chromosome (BAC) clones and three fingerprint contigs from the Atlantic salmon physical map that contains these markers. We made use of the extensive BAC end sequence database to extend these contigs by chromosome walking and identified additional two markers in this region. The BAC end sequences were used to search for conserved synteny between this segment of LG8 and the fish genomes that have been sequenced. An examination of the genes in the syntenic segments of the tetraodon and medaka genomes identified candidates for association with ISA resistance in Atlantic salmon based on differential expression profiles from ISA challenges or on the putative biological functions of the proteins they encode. One gene in particular, HIV-EP2/MBP-2, caught our attention as it may influence the expression of several genes that have been implicated in the response to infection by infectious salmon anemia virus (ISAV). Therefore, we suggest that HIV-EP2/MBP-2 is a very strong candidate for the gene associated with the ISAV resistance QTL in Atlantic salmon and is worthy of further study

The child as held in the mind of the mother: The influence of prenatal maternal representations on parenting behaviors

Using a longitudinal design, this study examined the relationship of a mother’s prenatal representation of her child and her parenting behavior with that child at one-year-of-age in a sample of women who were either exposed or not exposed to intimate partner violence (IPV) (n = 164; mean child age = 1.1 years, sd = .11 years; 52% male). Controlling for prenatal IPV, a MANCOVA analysis revealed that prenatal representational typology was significantly related to parenting behavior one year post-partum. Mothers whose representations were affectively deactivated (disengaged) were more behaviorally controlling with their children. Mothers whose representations were affectively overactivated (distorted) were more hostile with their children. Mothers with balanced representations demonstrated more positive parenting. Exposure to IPV did not moderate this relationship. There was no direct association between pre-natal or post-natal IPV and parenting behavior. These findings suggest that prenatal representations influence postnatal parenting behavior in significant and theoretically consistent ways and that this relationship functions similarly for both abused and non-abused women. Results add to the growing literature that internal representations serve to guide behavior throughout development and suggest that maternal working models may be one important link in the intergenerational transmission of attachment relationships

Bursts and Horizontal Evolution of DNA Transposons in the Speciation of Pseudotetraploid Salmonids

Background: Several genome duplications have occurred in the evolutionary history of teleostfish. In returning to a stable diploid state, the polyploid genome reorganized, and large portions arelost, while the fish lines evolved to numerous species. Large scale transposon movement has beenpostulated to play an important role in the genome reorganization process. We analyzed the DNAsequence of several large loci in Salmo salar and other species for the presence of DNA transposonfamilies.Results: We have identified bursts of activity of 14 families of DNA transposons (12 Tc1-like and2 piggyBac-like families, including 11 novel ones) in genome sequences of Salmo salar. Several ofthese families have similar sequences in a number of closely and distantly related fish, lamprey, andfrog species as well as in the parasite Schistosoma japonicum. Analysis of sequence similaritiesbetween copies within the families of these bursts demonstrates several waves of transpositionactivities coinciding with salmonid species divergence. Tc1-like families show a master gene-likecopying process, illustrated by extensive but short burst of copying activity, while the piggyBac-likefamilies show a more random copying pattern. Recent families may include copies with an openreading frame for an active transposase enzyme.Conclusion: We have identified defined bursts of transposon activity that make use of masterslaveand random mechanisms. The bursts occur well after hypothesized polyploidy events andcoincide with speciation events. Parasite-mediated lateral transfer of transposons are implicated