1,328 research outputs found
Thermodynamic Model of a Very High Efficiency Power Plant Based on a Biomass Gasifier, SOFCs, and a Gas Turbine
Thermodynamic calculations with a power plant based on a biomass gasifier, SOFCs and a gas turbine are presented. The SOFC anode off-gas which mainly consists of steam and carbon dioxides used as a gasifying agent leading to an allothermal gasification process for which heat is required. Implementation of heat pipes between the SOFC and the gasifier using two SOFC stacks and intercooling the fuel and the cathode streams in between them has shown to be a solution on one hand to drive the allothermal gasification process and on the other hand to cool down the SOFC. It is seen that this helps to reduce the exergy losses in the system significantly. With such a system, electrical efficiency around 73% is shown as achievable
Goat Milk Based Infant Formula in Newborns:A Double-Blind Randomized Controlled Trial on Growth and Safety.
Objectives: We aimed to determine the growth and safety parameters in newborns fed a goat milk based infant formula (GMF) using a randomized double-blind trial, in which a cow milk formula (CMF) served as a control and a breast fed (BF) group as a reference. Methods: Healthy term infants (n = 218) aged up to 14 days were recruited from 25 European study centers and randomized to GMF or CMF. Weight, length, head circumference were measured at baseline, and at 14, 28, 56, 84, and 112 days at the study clinics. Adverse events were recorded and stool characteristics, reflux, fussiness, colic, and flatulence were self-reported by parents in 3-day diaries. Anthropometric measurements were transformed to WHO standardized age- and sex-adjusted z-scores. Analyses of covariance and linear mixed modeling were used to statistically analyze growth, while adjusting for potential confounders when studying the breast-fed group (n = 86). Results: Comparing the GMF to the CMF group, weight gain [mean difference 227.8 g (95% CI -16.6 to -439.0)] and z-scores for anthropometric measurements were similar after 112 days intervention. Infant formula groups showed greater mean (SD) weight z-scores than the BF group from 84 days onwards (GMF: 0.28 (0.84), CMF: 0.12 (0.88), BF -0.19 (1.02), P < 0.05), whereas length and head circumference z-scores were similar. Incidences of serious adverse events and reflux, fussiness, colic, and flatulence were similar among the three groups. Conclusion: Our data demonstrate that GMF provides adequate growth, has a good tolerability, and is safe to use in infants
Beam Orientation Optimization for Intensity Modulated Radiation Therapy using Adaptive l1 Minimization
Beam orientation optimization (BOO) is a key component in the process of IMRT
treatment planning. It determines to what degree one can achieve a good
treatment plan quality in the subsequent plan optimization process. In this
paper, we have developed a BOO algorithm via adaptive l_1 minimization.
Specifically, we introduce a sparsity energy function term into our model which
contains weighting factors for each beam angle adaptively adjusted during the
optimization process. Such an energy term favors small number of beam angles.
By optimizing a total energy function containing a dosimetric term and the
sparsity term, we are able to identify the unimportant beam angles and
gradually remove them without largely sacrificing the dosimetric objective. In
one typical prostate case, the convergence property of our algorithm, as well
as the how the beam angles are selected during the optimization process, is
demonstrated. Fluence map optimization (FMO) is then performed based on the
optimized beam angles. The resulted plan quality is presented and found to be
better than that obtained from unoptimized (equiangular) beam orientations. We
have further systematically validated our algorithm in the contexts of 5-9
coplanar beams for 5 prostate cases and 1 head and neck case. For each case,
the final FMO objective function value is used to compare the optimized beam
orientations and the equiangular ones. It is found that, our BOO algorithm can
lead to beam configurations which attain lower FMO objective function values
than corresponding equiangular cases, indicating the effectiveness of our BOO
algorithm.Comment: 19 pages, 2 tables, and 5 figure
Development and pilot-testing of a colorectal cancer screening decision aid for individuals with varying health literacy levels
Objective: Making an informed decision about colorectal cancer screening requires health literacy. Our aim was to develop and pilot-test a computer-based decision aid to support informed decision making about whether or not to participate in colorectal cancer screening for individuals with varying health literacy levels in the Netherlands. Methods: First, we designed and adapted the decision aid prototype among 25 individuals with low (n = 10) and adequate (n = 15) health literacy. Second, we used a before/after study to assess changes in knowledge, attitude, intention, decisional conflict, deliberation, anxiety and risk perception in an online survey among 81 individuals eligible for colorectal cancer screening with low (n = 35) and adequate (n = 46) health literacy. Results: The decision aid was acceptable, comprehensible, reduced decisional conflict, increased deliberation and improved knowledge about colorectal cancer screening, but not about colorectal cancer, among individuals with adequate and low health literacy. Usability was slightly higher for participants with adequate health literacy compared to those with low health literacy. Conclusion: The decision aid is promising in supporting informed decision making about colorectal cancer screening, also among individuals with lower health literacy. Practice implications: Further refinement of interactive features, such as videos, animations and the values clarification exercise, is needed to increase the usability of the decision aid
MODELING OF A METHANE FUELLED DIRECT CARBON FUEL CELL SYSTEM
ABSTRACT Energy conversion today is subject to high thermodynamic losses. About 50 to 90 % of the exergy of primary fuels is lost during conversion into power or heat. The fast increasing world energy demand makes a further increase of conversion efficiencies inevitable. The substantial thermodynamic losses (exergy losses of 20 to 30 %) of thermal fuel conversion will limit future improvements of power plant efficiencies. Electrochemical conversion of fuel enables fuel conversion with minimum losses. Various fuel cell systems have been investigated at the Delft University of Technology during the past twenty years. It appeared that exergy analyses can be very helpful in understanding the extent and causes of thermodynamic losses in fuel cell systems. More than 50 % of the losses in high temperature fuel cell (MCFC and SOFC) systems can be caused by heat transfer. Therefore system optimisation must focus on reducing the need for heat transfer as well as improving the conditions for the unavoidable heat transfer. Various options for reducing the need for heat transfer are discussed in this paper. High temperature fuel cells, eventually integrated into gas turbine processes, can replace the combustion process in future power plants. High temperature fuel cells will be necessary to obtain conversion efficiencies up to 80 % in case of large scale electricity production in the future. The introduction of fuel cells is considered to be a first step in the integration of electrochemical conversion in future energy conversion systems. Keywords: Fuel cell systems; Exergy analysis; Thermodynamic analysis; System modelling; Cycle Tempo; PEMFC; MCFC; SOFC; Applications INTRODUCTION Today our world strongly depends on the availability of energy for almost all of their activities. Total energy demand is growing fast, in particular due to the development of the large Asian countries. To ensure our future energy supply the losses of energy conversion have to be reduced and the utilisation of available sources, in particular renewable sources, should be stimulated. Conversion of primary fuels into electricity, power, heat or secondary fuels is necessary to fulfil our energy demands. These conversions are involved with substantial thermodynamic losses. These losses should be presented as exergy losses to get a true representation of the thermodynamic performance of conversion systems. Exergy is the potential to obtain work from an amount of energy or from an energy flow; exergy values do represent a true yardstick for all relevant thermodynamic characteristics Exergy efficiencies are some percentage points lower than thermal efficiencies (based on the lower heating value of the fuel) in case of the conversion of primary energy into power. As thermal efficiencies of less than 50 % are normal practice exergy losses will on average be higher than 50 %. Thermal efficiencies are in general high (around 90 % or more) in case of heat generating systems, but exergy efficiencies are much lower depending on the temperature level at which i
What value structure underlies shared decision making?:A qualitative synthesis of models of shared decision making
Objective: To construct the underlying value structure of shared decision making (SDM) models. Method: We included previously identified SDM models (n = 40) and 15 additional ones. Using a thematic analysis, we coded the data using Schwartz's value theory to define values in SDM and to investigate value relations. Results: We identified and defined eight values and developed three themes based on their relations: shared control, a safe and supportive environment, and decisions tailored to patients. We constructed a value structure based on the value relations and themes: the interplay of healthcare professionals' (HCPs) and patients’ skills [Achievement], support for a patient [Benevolence], and a good relationship between HCP and patient [Security] all facilitate patients’ autonomy [Self-Direction]. These values enable a more balanced relationship between HCP and patient and tailored decision making [Universalism]. Conclusion: SDM can be realized by an interplay of values. The values Benevolence and Security deserve more explicit attention, and may especially increase vulnerable patients’ Self-Direction. Practice implications: This value structure enables a comparison of values underlying SDM with those of specific populations, facilitating the incorporation of patients’ values into treatment decision making. It may also inform the development of SDM measures, interventions, education programs, and HCPs when practicing.</p
What value structure underlies shared decision making?:A qualitative synthesis of models of shared decision making
Objective: To construct the underlying value structure of shared decision making (SDM) models. Method: We included previously identified SDM models (n = 40) and 15 additional ones. Using a thematic analysis, we coded the data using Schwartz's value theory to define values in SDM and to investigate value relations. Results: We identified and defined eight values and developed three themes based on their relations: shared control, a safe and supportive environment, and decisions tailored to patients. We constructed a value structure based on the value relations and themes: the interplay of healthcare professionals' (HCPs) and patients’ skills [Achievement], support for a patient [Benevolence], and a good relationship between HCP and patient [Security] all facilitate patients’ autonomy [Self-Direction]. These values enable a more balanced relationship between HCP and patient and tailored decision making [Universalism]. Conclusion: SDM can be realized by an interplay of values. The values Benevolence and Security deserve more explicit attention, and may especially increase vulnerable patients’ Self-Direction. Practice implications: This value structure enables a comparison of values underlying SDM with those of specific populations, facilitating the incorporation of patients’ values into treatment decision making. It may also inform the development of SDM measures, interventions, education programs, and HCPs when practicing.</p
An Impact Assessment of Effluent From the Water Treatment Plant Pinedo to Sustain the Albufera Natural Park
The aim of this research is to elaborate of the impacts on the use of the effluent of the water treatment plant Pinedo in the North of Albufera Natural Park in Valencia, Spain. Interviews and observations were conducted, which together created an Impact Assessment. To be able to see the influence of effluent on the water quality, an observation point in the north was compared to another observation point in the south. Besides that, a boat trip was made to observe the water quality on the lake. The result shows that eutrophication occurs as a cosequence of the wastewater from water treatment. Farmers have no choice and are happy to have a constant source. Fishermen have experienced a disastrous change in the seventies, but now see an improvement of the water quality. Environmentalists are most negative about the effluent inflow. The government understands the concerns and wants a higher quality of the effluent, but they do not have means to improve it. Water treatment plant Pinedo recognizes the corncerns either; however, the water quality already meets the requirements. Forecasting the future, everybody is slightly positive. The improvement of the quality of the effluent is a good thing and should carry on
Potential use of the alkaline comet assay as a predictor of bladder tumour response to radiation
Influence of different treatment techniques on radiation dose to the LAD coronary artery
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