193 research outputs found

    Assessing effects of permafrost thaw on C fluxes based on multiyear modeling across a permafrost thaw gradient at Stordalen, Sweden

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    Northern peatlands in permafrost regions contain a large amount of organic carbon (C) in the soil. Climate warming and associated permafrost degradation are expected to have significant impacts on the C balance of these ecosystems, but the magnitude is uncertain. We incorporated a permafrost model, Northern Ecosystem Soil Temperature (NEST), into a biogeochemical model, DeNitrificationDeComposition (DNDC), to model C dynamics in highlatitude peatland ecosystems. The enhanced model was applied to assess effects of permafrost thaw on C fluxes of a subarctic peatland at Stordalen, Sweden. DNDC simulated soil freeze–thaw dynamics, net ecosystem exchange of CO2 (NEE), and CH4 fluxes across three typical land cover types, which represent a gradient in the process of ongoing permafrost thaw at Stordalen. Model results were compared with multiyear field measurements, and the validation indicates that DNDC was able to simulate observed differences in seasonal soil thaw, NEE, and CH4 fluxes across the three land cover types. Consistent with the results from field studies, the modeled C fluxes across the permafrost thaw gradient demonstrate that permafrost thaw and the associated changes in soil hydrology and vegetation not only increase net uptake of C from the atmosphere but also increase the annual to decadal radiative forcing impacts on climate due to increased CH4 emissions. This study indicates the potential of utilizing biogeochemical models, such as DNDC, to predict the soil thermal regime in permafrost areas and to investigate impacts of permafrost thaw on ecosystem C fluxes after incorporating a permafrost component into the model framework

    Learning to Combat Chronic Pain: Exploring the Effectiveness of a Six-week Patient Psychoeducation Course Teaching Self-management of Chronic Pain

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    Abstract Chronic pain is a highly prevalent health problem in the U.S. and poses a large economic and temporal cost to the medical system (Institute of Medicine, 2011; Marcus, 2003). Patients with chronic pain typically report a decrease in emotional, social, and economic functioning (Bair et. al, 2009; Breen, 2002; Kang, Backstrand, & Parker, 2013). This study investigated the efficacy of a 6-week evidence-based group psychoeducation course for the self-management of chronic pain. Pre- and post-test measures were utilized to assess results of the course. Data were analyzed using a paired sample t-test in order to explore the relationship and degree of effect preand post-intervention, as well as comparing the treatment and control group results. Due to the small sample size, many of the results were not statistically significant. However, there was significant improvement in reported wellbeing within the treatment group. Moreover, there were observable changes in the control group- specifically an increased sense of pain disability and decreased sense of wellbeing- but these results were not statistically significant. Through the implementation of this study, several limitations and barriers to intervention were discovered. These discoveries provide valuable information for future applications of chronic pain management groups. If developers of these groups consider the insights gained in this study, the programs would prove to be a highly valuable resource to the medical and psychological community, in turn reducing the burden on primary care providers and improving patient wellbeing

    Information flow and product quality in human based assembly

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    Information is an important part of the manual assembly process. Information provides the user with the means to fulfil assembly tasks so that the right quality as well as high productivity are accomplished. This thesis addresses issues connected to information and information use in a modern manual assembly environment, and how these issues affect human operators, quality and productivity. The overall objectives of the research were to gain further knowledge on how attention affects the internal reject rate, to investigate these phenomena in industrial and laboratory environments and finally to propose a suitable evaluation method to be utilised at the design stage of an information system. Studies were performed with the purpose of investigating how the assembly personnel were affected by the information and how it affected quality and productivity. The studies were performed in an assembly plant and in the laboratory. Quantitative data collection included 10 days and nights of production where the information impact on quality was investigated. Connected to this study was a qualitative survey performed among 171 persons from the assembly personnel. The laboratory study took place during three days, approximately eight hours each day. It involved 30 persons, all experienced assembly workers from the reference assembly plant. The focus of this study was how information affected the personnel and thereby the productivity. The findings revealed that information affected the quality rates and productivity and that this can be linked to how the information is presented as well as when the information is presented. It was possible to link these findings to the outcome of a successful information search process, and to conclude that a use of an evaluation method or work process during the product lifecycle could have made it possible to avoid some of the problems connected to the information presentation. This is the basis for a proposed pragmatic evaluation method. The method was tested as a support system during the design of a prototype user interface to be used at the pilot plant. The major contribution of this research is the connection between attention and quality as well as the connection between attention and productivity. Knowledge regarding the importance of presenting the information at the right time must also be regarded as an important and proven contribution.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Inadequately presented information and its effect on the cognitive workload

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    The design and handling of information in manual assembly is becoming increasingly important in achieving effective and competitive assembly. However, the information provided to the assembly personnel in the automotive industry is usually poorly designed and presented, which can cause unnecessary mental stress and increase cognitive workload. Due to inadequate information, the original goals are placed aside and the workers are forced to figure out where the right information is located and how to access it within the system. One way of supporting the assembler could be to use kitting, which is a material supply principle where the assembler is provided with a kit of components that together support one or more assembly operations. The kit can also be considered as a carrier of information that complements or even replaces conventional assembly instructions. The aim of this paper is to initiate a theoretical exploration of the relationship between the assembler’s information needs and the kitting box, by investigating the kitting box and its potential to provide enough information for the assembler to fulfil the assembly task

    Nutritional adequacy of meals from an independent catering facility versus chain restaurants for young adults

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    BACKGROUND: Eating out of home has been associated with the increasing prevalence of obesity. While some chain restaurants provide nutritional information for their products, smaller independent catering facilities may not provide such information. The aim of this study was to assess the nutritional adequacy of meals provided to young adults at an independent catering facility and compare them with meals provided by chain restaurants. METHODS: Meals were analysed in 2014 in the UK in relation of nutrient provision to targets for macro- and micro-nutrients. One-way ANOVA was performed to compare menus between the restaurants included in the analyses. RESULTS: 2056 meal combinations were analysed, 210 from the student accommodation and 1,846 from five largest national chain restaurants. Mean (SD) nutritional content was: student accommodation: 1193(269)kcal, fat 52.0(22)g, saturated fat 24.5(14.5)g, protein 42.4(28.5)g, carbohydrate 117.0(30)g; chain restaurants: 922(160)kcal, fat 40.0(9.7)g, saturated fat 14.5(5.8)g, protein 31.2(6.5)g, carbohydrate 104.2(16.6)g. Meals from the student accommodation presented significantly more calories than the meals in all five chain restaurants ( p = 0.0015). CONCLUSIONS: Meal provision in the student accommodation was in excess of energy requirements and higher than the meals offered in chain restaurants. Regulating or setting nutritional standards for all places that provide food is essential as current food provision may favour unwanted weight gain and diet-related diseases

    Kitting as an information source in manual assembly

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    In manual assembly, a strategy to meet the goal of efficient production is the increased use of kitting as a material supply principle. Even though kitting is already implemented in industry, there are still uncertainties regarding the effects of introducing kits, particularly from a human factors perspective. This paper presents initial steps in the development of a method to be used for the evaluation of kitting. This from an information source point of view and for studying effects related to productivity and quality. The methodology is projected to act as a foundation for how to carry out a subsequent comprehensive case study. The purpose of the case study is to explore how kitting affects the cognitive workload compared to the ordinary material rack combined with part numbers used in the current manufacturing industry. This is done by measuring productivity; time spent on assembling a product, and quality; number of assembly errors. One step in the methodology development process, which is described in this paper, was to conduct a pilot study, primarily to test the methodology related to the selection of measurement parameters, as well as for getting experiences from running the methodology with real test subjects

    Parameters affecting quality in manual assembly of engines

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    In manufacturing, it is vital that operators and other production personnel have the right information at the right time and right place. But what happens if we overestimate the usability of information for supporting the personnel in their assembly tasks?When does information serve as a quality assurance tool, and when does it become a too large part of the workload, thus reducing the time for core workplace activities, and instead becoming a part of the personnel’s workload? This paper reports on work that has been conducted at a heavy diesel engine assembly plant with the aim of finding information usability parameters that can affect the personnel negatively or positively. The paper presents and describes an evaluation of an existing information system at the plant. The aim of the evaluation was to find out why the assembly personnel, despite the fact that they had “all the information they needed”, did not always assemble the product according to specification and thereby caused an engine reject that had to be re-assembled. The initial hypothesis was that there would be a strong correlation between the production volume and the number of rejects due to “Information Overload”. However, the study revealed that the personnel do not use the IT system in a way that causes information overload. Instead, the degree to which the IT system supports/triggers different forms of information seeking behaviour is thought to be one of the main factors influencing internal reject

    An assembly line information system study

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    Assembly line information systems are designed to provide assembly workers with appropriate information that allows the assembly of the product in good time and good quality. In this context product quality might be defined relative to the number of internal rejects or products which need some kind of reworking before being in a deliverable condition. This paper describes a pilot study of a heavy diesel engine assembly line where considerable variety is presented to the assembly workers in the form of engines destined for trucks, buses, marine applications and stationary power generation each of which has to comply with a variety of national and international standards. Internal rejects might for example occur through the fitting of subassemblies that are unsuited to the eventual application, and although an extensive information system is currently in place the level of internal rejects is considered to be unsatisfactory. The objectives of the study were to understand how the assembly workers interact with information systems and the impact this has on product quality and productivity. A single line was studied for ten days during which 2600 engines were assembled. At four of the assembly stations the existing information system was changed to reduce the amount of information to be assimilated by the workers, the timing of its presentation and its location. The use of simple colour-coded cards and symbols resulted in the reduction of internal rejects by 40% on two of the assembly stations and to zero on the other two stations. It is believed that changing the information system has changed the workers' behaviour through a reduction in cognitive stress levels. The pilot study has provided useful insights into the basis for modifying information systems and a further study of the final assembly of heavy trucks is planned with an ultimate aim of determining a rationale for the design of information systems for use within the assembly of customised products
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