Arbetet är ett utvecklingsprojekt som inriktar sig på utveckling av ett nytt avstickskär till bearbetning av smådetaljer. Avstickskäret ska optimeras för användning inom längdsvarvar vilket gör att problem som bland annat överhäng och nedböjning sätts i fokus. Arbetet är utfört på WhizCut AB i Helsingborg med syftet att minska materialåtgången som uppstår vid avstick av diametrar som är mindre än 13 mm. Det ska göras genom att utveckla och konstruera ett stickstål som kan användas under samma förhållande som konventionella system men med en mindre skärbredd. Den mindre skärbredden gör att materialåtgången minskas vilket är en fördel för massproduktion alternativt produktioner med exklusiva material som bland annat titan och rostfritt stål. Metoder som används är femstegsmetoden för produktutveckling där brainstorming används for att få fram nya idéer och konkurrenternas lösningar på liknande problem undersöks. För att säkerställa produktens styrka och även jämföra med konventionellt system används balkteori och FE-analys med hjälp av Inventor Professional 2020. Resultatet är ett tvåskärigt skär med båda skäreggarna riktade mot arbetstycket, detta gör att överhänget för processen kan minskas med mer än 30% samtidigt som böjstyvheten för skäret ökar med mer än 50%. Ett minskat överhäng och ökad böjstyvhet gör att skäret kan användas i tuffare miljöer med högre skärhastighet och matning för ökad produktivitet eller ersätta konventionella system med ett smalare skär. Det smalare skäret minskar konsumenternas materialåtgång vilket leder till att både konsument och miljön vinner på detta koncept. / This project focuses on developing a new system for parting of small parts.The tool must be optimized for usage in a swiss type lathe which concludes that problems including overhang and bending of the cutting edge has a majorpart in this project. This project is carried out at WhizCut AB with the purpose to reduce material waste during parting off operations at maximum diameter 13 mm. This will be done by developing a parting off tool that can be used under the same conditions as conventional tools but with a reduced cuttingwidth. The reduced cutting width results in reduced material waste which is anadvantage mass production and production in exclusive materials such as titanium and stainless steels. Methods that are used during the project is a fivestep development process that includes brainstorming to generate new ideasand competitors solutions to similar problems is looked into. To ensure that thestrength of the product and also compare with the conventional system calculations for beam theory and FEA-analyses is used in Inventor Professional 2020. The result is a two-cutting edge insert with both edges located against the workpiece, this makes it possible to reduce the overhang with more than 30% and a the same time increase the stiffness of the insert with more than 50%. Due to reduction in overhang the insert can be used in more demandingenvironments with increased cutting data or replace conventional system witha more narrow tool without changing the cutting parameters. The more narrow tool reduces material waste which is profitable for both end user and theenvironment.

Inquiries have been made by the Carnegie Commission on Higher Education and the United States Department of Health, Education, and Welfare to determine how colleges and universities could meet the financial crisis now being faced. One of the recommendations made by both agencies as a result of their investigations was that curriculum planners at these institutions provide students with opportunities to have off-campus experiences, preferably in their chosen career areas, before they are graduated to determine whether they want to pursue their studies in that area or reorient themselves to other options. These planned stopouts, they suggested, would curtail drifting or hanging on as well as enable students to gain practical experiences at various stages in their training. There is a lack of information in the literature to justify immediate response to the suggestions made by the private and public bodies mentioned. Time does not permit officials to conduct longitudinal studies based on an experimental design which would provide a basis to accept or reject these recommendations. This study represents an effort to investigate the effects of stopping out on former students. Admittedly it has limitations, particularly those inherent in ex post facto research, but does provide some results which may assist administrators and faculties as they make decisions in light of the crisis now facing them. The results of this study indicate that students who have stopped out are more likely to change their academic major than students who have not stopped out. Also, there are indications that stopping out does not affect academic standing. However, it was found that for most students grades get higher as they progress through school whether they stop out or stay in. This finding is in agreement with findings from previous studies reported in the literature.

No description available.

No description available.

In order to maximize fitness, individuals must partition their limited resources among competing physiological processes, creating negative statistical associations between processes known as “life-history trade-offs”. Evidence indicates that individuals tend to decrease their reproductive investment when confronted with a significant immunological challenge in order to increase investment in immune defense. This trade-off is often accompanied by a significant decrease in the sexual signal, which provides an honest signal of the male’s infection status to potential mates. However, if individual residual reproductive value is low, they may instead increase their reproductive investment to maximize reproductive success before the end of their life (a.k.a. terminal investment). Here, we investigate the potential for terminal investment in the ground cricket Allonemobius socius by inoculating males with varying dosages of an immune challenge. We predicted that both high dose and advanced male age would induce terminal investment. Furthermore, we predicted that terminally investing males would produce a dishonest signal by increasing their signaling effort. We found that upon infection We found that upon infection, young males and old males differentially alter their reproductive strategy. Young males exhibited the classic deceleration of reproductive effort. However, old males increased their calling song energetics and decreased their parental investment (nuptial gift size), suggesting that old males are dishonestly signaling their condition to the female.

The research presented in this thesis is to evaluate the feasibility of demountable shear connectors as an alternative to welded shear connectors in composite structures through push off tests and composite beam tests. Push off tests were conducted to examine the shear strength, stiffness and ductility of demountable shear connectors in composite structures. The experimental results showed that demountable shear connectors in composite structures have very similar shear capacity to welded shear connectors. The shear capacity was compared against the prediction methods used for the welded shear connections given in Eurocode 4 and AISC 360-10 and the methods used for bolted connections in Eurocode 3 and ACI 318-08. It was found that the AISC 360-10 and ACI 318-08 methods overestimated the shear capacity in some cases. The Eurocode method is conservative and can be utilised to predict the shear capacity of demountable connectors in composite structures. The experimental studies of two identical composite beams using demountable shear connectors and welded shear connectors showed very similar moment capacity. However, the specimen with demountable shear connectors was more ductile compared to the welded specimen. The experimental study suggests that the methods available in Eurocode 4 and BS 5950 for predicting moment capacity and mid span deflection can be adopted for composite beam with demountable shear connectors. In addition, a finite element analysis of push off test and beam test with demountable shear connectors was also conducted for parametric studies and results are used to evaluate the behaviour of composite structures. / EPSRC and the University of Bradford

Ankle foot orthoses (AFOs) are used to improve walking in some lower extremity conditions but AFOs restrict ankle motion resulting in a trade-off in ankle and hip mechanics. While the use of AFOs have been well documented, there still remain gaps in the literature. The first study compared the differences in sagittal plane ankle and hip kinematics and kinetics across three conditions at two speeds in healthy individuals while the second study compared frontal plane kinetics at the hip and knee and vertical ground reaction forces between two conditions at two speeds in healthy individuals. This was studied by collecting and analyzing three-dimensional joint kinematics and ground reaction forces from twelve healthy adults. Participants walked in three conditions (shod; i.e. athletic shoes only and two reduced push-off conditions using solid ankle foot orthoses (SAFOs); i.e. unilateral brace and bilateral brace conditions) and at two speeds (1.25m/s and 1.5m/s). In the first study, generalized linear models with general estimating equations were used to compare ankle and hip angles, moments and power for the braced and unbraced sides separately in all three conditions. In the second study, frontal plane kinetics and vertical ground reaction forces in the unbraced limb in the unilateral brace condition were compared to the same side during shod walking using paired sample t-tests. From our first study we found that the reduced push-off from the use of SAFOs results in decreased peak plantarflexion angles and power generation at the ankle and increased peak flexion angles, and first and second peak power generation at the hip in the braced limbs in both unilateral (p≤0.05) and bilateral (p≤0.05) brace conditions at both speeds. On the unbraced side in the unilateral brace condition, there were decreased peak power generation at the ankle at 1.25m/s and increased peak extension moments, first and second peak power generation at the hip compared to the shod condition (p<0.05) at both speeds. In the comparison between the unilateral and bilateral brace conditions, the changes in ankle and hip mechanics were similar to the changes between the shod condition and the bilateral brace condition on the unbraced side; in addition, participants also had higher peak extension moments in the unilateral brace condition compared to the bilateral brace condition (p<0.05). On the braced side, participants had lower peak plantarflexion moments at the ankle and lower peak flexion angles at the hip when walking with bilateral SAFOs, compared to walking with unilateral SAFOs (p<0.05). In the second study, we found that peak internal knee and hip abduction moments were 3% and 4% higher, respectively, in the unbraced limb in the unilateral brace condition at 1.25m/s (p≤0.041) compared to the same side in the shod condition. Peak vertical ground reaction force was 3% higher in the unbraced limb in the unilateral brace condition at both speeds (p=0.002). Findings indicate that walking with unilateral ankle foot orthoses presents an increased risk of developing secondary conditions.

When to reproduce for the first time is a key question in evolutionary ecology. Indeed, age at first reproduction has clear impacts on population dynamics and fitness. Breeding early in life may impair survival due to a resource allocation trade-off between survival, growth, and reproduction. Postponing reproduction, however, reduces reproductive opportunities and increases the chances of dying before reproducing. Here, I investigate the consequences of age at first reproduction on both survival and lifetime reproductive success by using long-term monitoring data of a population of yellow-bellied marmots (Marmota flaviventer) at the Rocky Mountain Biological Laboratory (Colorado, USA). Mixed models were employed to analyze the relationships between age at first reproduction in females and their lifetime reproductive success, as well as three survival components: longevity, the number of years after first reproduction, and annual survival probability. The results showed that postponing reproduction until 2 years of age increased longevity, but delaying it beyond 2 years did not yield additional survival benefits. Females reproducing for the first time after 3 years exhibited high rates of actuarial senescence. Furthermore, delaying first reproduction beyond 3 years old did not lead to a compensatory increase in lifetime reproductive success that would offset the reduction in survival associated with postponing first reproduction. These results suggest that the optimal age at first reproduction, in terms of survival and reproductive success, is 2 years. The reproductive strategy might be governed by body condition or environmental factors. These findings shed light on the trade-offs between early reproduction and survival, as well as reproductive success, illustrating the complexity of reproductive strategies in relation to individual fitness.

No description available.

Growing winter cereal cover crops (WCCCs) has been identified as an effective in-field practice to reduce nitrate-nitrogen (N) and total phosphorus (P) losses to Upper Mississippi River Basin, USA. In this region, however, growers are reluctant to plant WCCCs prior to corn (Zea mays L.) due to soil N immobilization and corn establishment issues. Two strategies to minimize these issues are (i) incorporating legumes and brassicas into WCCCs as mixtures and (ii) precision planting of cover crops. The objective of chapter 1 was to (i) evaluate the effect of cover crop mixtures vs a no-cover crop control on soil health indicators and (ii) assess the impact of precision planting of cover crops on soil nutrient availability, soil nutrient stratification, soil permanganate oxidizable carbon (POXC) and soil organic carbon (SOC) stocks “on” and “off” the corn row over three depths (0-5, 5-20, and 20-90 cm). Treatments were (i) a no-cover crop control (NCC); (ii) no cover on corn row, hairy vetch (V) on middle row, and winter cereal rye (WCR) on the outside row of corn (NOVR); and (iii) oats (Avena sativa) and radishes (Raphanus sativus) on the corn row, V on the middle row, and WCR on the outside row (ORVR). Our results indicated NCC had lower SOC stocks than the NOVR and ORVR only at 0-5 cm depth. Soil POXC was more sensitive to cover crop management than SOC, and POXC concentrations were higher in ORVR at 5-20 cm than the NCC control. At 0-5 cm depth, cover cropping increased Bray-1 soil test P (STP). Soil test P declined over depth reflecting its immobility in the soil. Mehlich-3 soil test K (STK) was higher in cover crop treatments than the no-cover crop control at 0-5 cm depth. Soil test K was higher on corn row indicating that the oats and radish mix and corn residue decomposition releases K detectable in soil as Mehlich-3 K. Soil test sulfur was similar among treatments but higher at 20-90 cm depth reflecting S leaching and/or potential anion exchange capacity at depth that can lead to subsoil sulfate-S accumulation. These results indicate cover cropping in the fragipan belt / Alfisols of the Upper Mississippi River Basin can benefit soil after six years, but soil C benefits are limited to surface soil depths.In Chapter 2 the objectives were to (i) evaluate the biomass, nutrient concentration, and uptake of precision planted cover crop mixtures; (ii) assess whether precision planted cover crops influence corn stand density, grain yield, yield components, and nutrient balances; identify the best economically viable precision planted mixture prior to corn. Treatments were (i) a no-cover crop control (NCC); (ii) no cover on corn row, hairy vetch (V) on middle row, and winter cereal rye (WCR) + annual rye (AR) on the outside row of corn (RVSKIP); and (iii) no cover on corn row, clover (C) on the middle row, and WCR + AR on the outside row (RCSKIP). Results indicated that RVSKIP was always high yielding, with high N uptake, and low C:N ratio (25) suggesting it could release N throughout the corn growing season without immobilizing N. Cover crops influenced corn population only in one site-yr but that did not result in lower corn grain yield reflecting corn potential for filling the plant gap by creating larger ears with heavier grain (TKW). Similar corn grain in all cover crop treatments was mainly due to adding optimum N as fertilizer. We concluded that overall, cover cropping could benefit soil over a six-year period but to optimize their benefit to corn, adjustments to N should be made. Therefore, future research should focus on revisiting corn N requirement especially in cover crop mixtures with high percentage (>50%) of legumes in the mixture to determine the fertilizer value of the cover crops.