42 resultados para orthogonal experiment


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Introduction Improving infrastructure to support walking and cycling is often regarded as fundamental to encouraging their widespread uptake. However, there is little evidence that specific provision of this kind has led to a significant increase in walking or cycling in practice, let alone wider impacts such as changes in overall physical activity or carbon emissions. Connect2 is a major new project that aims to promote walking and cycling in the UK by improving local pedestrian and cycle routes. It therefore provides a useful opportunity to contribute new evidence in this field by means of a natural experimental study.

Methods and analysis iConnect is an independent study that aims to integrate the perspectives of public health and transport research on the measurement and evaluation of the travel, physical activity and carbon impacts of the Connect2 programme. In this paper, the authors report the study design and methods for the iConnect core module. This comprised a cohort study of residents living within 5 km of three case study Connect2 projects in Cardiff, Kenilworth and Southampton, supported by a programme of qualitative interviews with key informants about the projects. Participants were asked to complete postal questionnaires, repeated before and after the opening of the new infrastructure, which collected data on demographic and socioeconomic characteristics, travel, car fuel purchasing and physical activity, and potential psychosocial and environmental correlates and mediators of those behaviours. In the absence of suitable no-intervention control groups, the study design drew on heterogeneity in exposure both within and between case study samples to provide for a counterfactual.

Ethics and dissemination The study was approved by the University of Southampton Research Ethics Committee. The findings will be disseminated through academic presentations, peer-reviewed publications and the study website (http://www.iconnect.ac.uk) and by means of a national seminar at the end of the study.

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A detailed study of martensitic transformation crystallography and microstructural characteristics in the Ni53Mn25Ga22 ferromagnetic shape memory alloy (FSMA) was performed by both experimental observation and theoretical calculation. It is revealed that there are two microscopically twin-related martensitic variants with a misorientation of ∼82° around the 〈1 1 0〉M axis in each initial austenite grain. The twin interface plane was determined to be {0.399 0.383 0.833}M (1.79° away from {1 1 2}M). The ratio of the amounts of the two variants inherited from one single austenite grain is about 1.70. The prevalent orientation relationship between austenite and martensite was found to be Kurdjumov–Sachs (K–S) relationship with (1 1 1)A//(1 0 1)M, [110]A//[111]M. A successful explanation of the crystallographic features during martensitic transformation will shed light on the development of FSMAs with optimal performance.

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The importance to food-webs of trophic cul-de-sacs, species that channel energy flow away from higher trophic levels, is seldom considered outside of the pelagic systems in which they were first identified. On intertidal mudflats, inputs of detritus from saltmarshes, macroalgae or microphytobenthos are generally regarded as a major structuring force underpinning food-webs and there has been no consideration of trophic cul-de-sacs to date. A fully orthogonal three-factor experiment manipulating the density of the abundant gastropod, Pyrazus ebeninus, detritus and macrobenthic predators on a Sydney mudflat revealed large deleterious effects of the gastropod, irrespective of detrital loading or the presence of predators. Two months after experimental manipulation, the standing-stock of microphytobenthos in plots with high (44 per m2) densities of P. ebeninus was 20% less than in plots with low (4 per m2) densities. Increasing densities of P. ebeninus from low to high halved the abundance of macroinvertebrates and the average number of species. In contrast, the addition of detritus had differing effects on microphytobenthos (positively affected) and macroinvertebrates (negatively affected). Over the two-months of our experiment, no predatory mortality of P. ebeninus was observed and high densities of P. ebeninus decreased impacts of predators on macroinvertebrate abundances. Given that the dynamics of southeast Australian mudflats are driven more by disturbance than seasonality in predators and their interactions with prey, it is likely that Pyrazus would be similarly resistant to predation and have negative effects on benthic assemblages at other times of the year, outside of our study period. Thus, in reducing microphytobenthos and the abundance and species richness of macrofauna, high abundances of the detritivore P. ebeninus may severely limit the flow of energy up the food chain to commercially-important species. This study therefore suggests that trophic cul-de-sacs are not limited to the eutrophied pelagic systems in which they were first identified, but may exist in other systems as well.

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This paper describes a new experiment for studying crevice corrosion. A wire beam electrode was employed in this experiment to measure electrochemical parameters directly from crevice area and these parameters were used to calculate instantaneous crevice corrosion kinetics. A clear correlation between calculated corrosion depth map and real corrosion appearance was obtained.

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Laboratory practicals form an essential component in any electronics or electrical engineering course. Many students choose to study engineering by means of distance education. Providing such students with effective and manageable practical experience has always been a significant challenge for those involved in providing distance education. Our university has employed an experimental electronics kit for teaching laboratory skills to distance-education students over the past several years. The chief limitation of the early kit was the inability to use it for performing AC experiments without an additional AC signal generator and an oscilloscope. We now supply distance-education students with the original components pack, and an additional “HELP” kit which contains the signal generator, PC-oscilloscope, a basic multimeter, logic probe, software and documentation. The combined kits allow these students to perform basic DC and AC electronics experiments at home in both freshman and sophomore electronics courses. A more recent development is introducing a small robot platform intended to enhance the student experience and interest in electronics and mechatronics, while still covering the basic skills necessary for the engineer-in-training. Distance-education students receive an updated experimental kit containing the robot, other equipment and components to allow them to complete a fuller suite of practical exercises in electronics in their first two years of study. Within this paper, we present these developments in our HELP kit and also make comparisons between on-campus and off-campus performance.

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The impact of salmon farming on the environment has been widely studied; there is, however, no consensus on the magnitude and quality of these effects and little information on their extent over large salmon farming areas. Forty-three salmon farm sites of which 29 are in full operation and grouped in nine locations in southern Chile were evaluated. Using statistical methods (two-way anova), no effects were found on water column variables such as nitrate, ammonia, orthophosphate and chlorophyll, whereas they were significant on sediment variables such as nitrogen (N), phosphorus (P) and organic carbon (OC), among others. Natural variability evaluation of some parameters revealed that P in sediments had the lowest coefficient of variation (23.2%) when compared with N (65.2%), particulate organic matter (POM) (139%) and OC (39%), and showed more marked salmon farming effects with no locality effects. Four of the nine locations showed stronger effects on sediments, with average P values ranging from 150 to 230 mmol that were six to nine times higher than in control sites (25 mmol). Nitrogen and carbon in sediments, while showing significant effects on salmon farming, also showed locality effects that revealed other biogenic processes influencing sediment composition. Thus, P in sediments was proposed as a promising indicator of impact on salmon farming, although the relationship with fauna in sediments was not linear and somewhat variable; more research is therefore needed to understand such connections. Considering entire geographical locations, no relationship was found between sediment conditions under salmon cages and the condition of the water column at a farm. This may indicate the possibility of high dilution rates and recycling processes, which so far preclude the detection of more global impacts beyond the cages shadow.

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By 2050, it is projected that Melbourne will have a population of between 5.6 and 6.4 million (DPCD, 2012), an increase of nearly 50% above its current level. Despite Melbourne's status as the world's most liveable city, a recent survey found that Australians in general found smaller cities are better places to live and bring up families (Perkins, 2013). The Grattan Institute's report entitled "The Cities We Need" was "an invitation to a conversation" about our future cities (Kelly, 2010:5). One idea not canvassed in the report was that of decentralization to accommodate Melbourne's projected growth. In its discussion paper, "Let's Talk about the Future", the Victorian State Government proposes that Melbourne become a 'polycentric city' linked to its regional cities (DPCD, 2012). While growth in the present regional cities is acknowledged, the possibility that these and other new regional cities could absorb the future population projected for Melbourne is not considered, nor that these regional cities could be transformed into 'sustainable cities'. This paper explores the idea that a network of smaller 'midi-cities, based on the sustainable city concept of Sweden, might provide a better alternative to concentrated growth in one city. Fifteen new cities of 150,000 would be required to absorb the projected extra 2.3 million Victorian residents. The paper analyses the energy, food, water and land requirements of a typical sustainable city. The new cities would require approximately 12% of the State's land area for food and energy supply, as well as the built environment.

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The foraging benefits of coloniality, whereby colony members exchange information about food location, have been suggested as a primary factor influencing the evolution of coloniality. However, despite its longstanding popularity, this hypothesis has rarely been tested experimentally. Here, we conducted a field experiment in the wild Zebra Finch Taeniopygia guttata to test whether colonial birds are better at finding food than solitary individuals. We manipulated food patch location and directly measured foraging activity of many colonial and solitary parents at those patches using an electronic monitoring system. We provided nesting sites in excess to alleviate nest site competition and manipulated brood size to eliminate the possible correlation between brood size, nesting density, and individual quality (including foraging activity). We found that solitary birds found experimental food patches first, closely followed by colonial birds. Moreover, solitary parents adjusted the amount of food per nestling to experimental brood size, whereas colonial parents did not, although overall, nestlings were fed more per capita in colonial than in solitary nests. In addition, brood size and, to a lesser extent, nesting density negatively affected nestling growth. Therefore, with the effect of provisioning rate, sibling competition, and cost of coloniality combined, nestling mass was not affected by the brood manipulation in solitary nests, whereas nestlings were lighter in enlarged than in reduced broods in colonies. Our results therefore suggest that individuals settling in solitary nests were intrinsically better foragers and more optimal parents. While they do not invalidate the possibility of information transfer at colonies, our findings highlight the importance of considering settlement bias in future studies and add to the existing evidence that the effects of nesting density on fitness are both complex and multiple.

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The main purpose of thesis is to estimate the value of the ecosystem services of the Bung Khong Long through two techniques. The per hectare value estimated by economic valuation method is US$ 976 per annum. MRA-benefit transfer approach produces values of between US$ 396 and US$ 1,369 per annum.