293 research outputs found
Novel Ag-doped glass frits for high-efficiency crystalline silicon solar cells
No full textGlass frits play an important role in the front contact electrodes of crystalline silicon (c-Si) solar cells. In this work, we developed a novel glass frit by doping Ag into a glass frit in the process of hightemperature synthesis. When the Ag paste including this novel glass frit was used as the front contact electrode of silicon solar cells, the conversion efficiency of poly-crystalline silicon (pc-Si) solar cells was improved by 1.9% compared to the glass frit without Ag. Through SEM characterisation and calculation of series resistance, we further found that the interface between Ag and Si was improved and the contact resistance of Ag and Si was greatly reduced, which were believed to be responsible for the improvement of solar cell performance. This work shows great guidance significance to develop novel and highly efficient commercial glass frits applied in solar cells in the future.Guangdong Innovative and Intrepreneurial Research Team Program [2013N080]; Peacock Plan [KYPT20141016105435850]; Shenzhen Key Lab [(2012)780, ZDSY20130331145131323]SCI(E)ARTICLE466239-62425
Choosing the corporate future. Technology networks of chiose concerning the creation of high performance fiber technology
No full textThis study deals with the question of what determines the outcomes of the choices made by large corporations when they develop new technology. To this end, four types of choice made in the course of the development of technology are distinguished in Chapter one:
- concerning the entrance to a scientific./technological research domair.
- coocerning the product to be developed and its characteristics.
- concerning the processes and additional techaologies to be developed in order to be able to manufacture and sell the product efhciently.
- concerning the construction of large scale production facilities.
Zie: Summery
The Khorana score for prediction of venous thromboembolism in cancer patients: a systematic review and meta-analysis
No full textWe aimed to evaluate the performance of the Khorana score in predicting venous thromboembolic events in ambulatory cancer patients. Embase and MEDLINE were searched from January 2008 to June 2018 for studies which evaluated the Khorana score. Two authors independently screened studies for eligibility, extracted data, and assessed risk of bias. Additional data on the 6-month incidence of venous thromboembolism were sought by contacting corresponding authors. The incidence in each Khorana score risk group was estimated with random effects meta-analysis. A total of 45 articles and eight abstracts were included, comprising 55 cohorts enrolling 34,555 ambulatory cancer patients. For 27,849 patients (81%), 6-month follow-up data were obtained. Overall, 19% of patients had a Khorana score of 0 points, 64% a score of 1 or 2 points, and 17% a score of 3 or more points. The incidence of venous thromboembolism in the first six months was 5.0% (95% CI: 3.9-6.5) in patients with a low-risk Khorana score (0 points), 6.6% (95% CI: 5.6-7.7) in those with an intermediate-risk Khorana score (1 or 2 points), and 11.0% (95% CI: 8.8-13.8) in those with a high-risk Khorana score (3 points or higher). Of the patients with venous thromboembolism in the first six months, 23.4% (95% CI: 18.4-29.4) had been classified as high risk according to the Khorana score. In conclusion, the Khorana score can be used to select ambulatory cancer patients at high risk of venous thromboembolism for thromboprophylaxis; however, most events occur outside this high-risk group
Improving identification of HT-ATES performance drivers and -barriers
No full textHigh temperature aquifer thermal energy storage (HT-ATES) can potentially solve the mismatch between heat supply and demand. It can provide a large scale seasonal heat storage solution. Thereby it enables an increase in full load hours of the base heat source, which can benefit project performance on both costs and emissions. However, the limited number of successful pilot projects indicates the technology has not escaped its state of infancy. There is a gap from concept to implementation, which is signified by the disagreement of experts on performance drivers and barriers of HT-ATES. This research aims to narrow the described knowledge gap, by improving identification of HT-ATES performance drivers and barriers. Thereby it strives to improve decision making of HT-ATES implementation, and further enhance future HT-ATES application in heating projects. The broad scope of research demands both a diagnostic and design-orientated approach, and fits seamlessly with a multi-criteria decision analysis. The analysis entails the stages of creating, evaluating, comparing and ranking of case-specific scenarios. Parametric variation changes the conditions for HT-ATES implementation across the scenarios. A simulation model is developed and connected to a groundwater model to apply the parametric variation, to create the different scenarios, and consequently to produce the quantitative information for further evaluation. During the stages of creating, evaluating, comparing and ranking, the methodology systematically produces new results on the opportunities and risks introduced by HT-ATES, and additionally on the HT-ATES performance drivers and barriers. The results show that HT-ATES enables the opportunity of improving project performance with respect to the internal rate of return and emissions. Groundwater impact remains the greatest risk, but it can be minimised with smart decision making. To support the decision maker and to overcome the risk of groundwater impact, the research proposes several performance-enhancing, non-explicit guidelines. The guidelines focus on realising an HT-ATES implementation, where project performance with respect to internal rate of return, emissions and groundwater impact are balanced. Thereby they explain the major HT-ATES performance drivers and barriers. The guidelines are summarised below. The decision maker is recommended to .. 1. .. minimise the uncertainty, through thorough subsurface characterization before implementation. Secondly, to focus on aquifers with a minimum depth of 200 [m] and a minimum hydraulic conductivity of 5 [m/d] 2. .. assure network return temperatures during peak demand are below expected storage temperatures 3. .. not consider project life-times exceeding 20 years 4. .. assure yearly maximum base source heat production is always lower than yearly consumer heat demand 5. .. to strive for a flat demand curve and apply peak-shaving, by means of, for example, variable heat prices Currently, the guidelines have the purpose of giving direction to the decision maker, but they will become more explicit once the methodology is improved, and the uncertainty and number of assumptions in the model is decreased.Electrical Engineering | Sustainable Energy Technolog
Batteries and energy arbitrage: A techno-economic analysis of electricity arbitrage opportunities for utility-scale battery energy storage in the Netherlands
No full textAs the variable renewable energy share keep on increasing throughout the energy transition, power systems require more and different flexibility measures. Battery energy storage can provide these essential services that enable the energy system to carbonise and transform on short time scales. Energy arbitrage, the trading of electricity on the electricity markets, can create economic value for batteries. This research assesses the energy arbitrage opportunities for utility-scale battery energy storage in the Netherlands. It compares five different battery technologies and defines the optimal size and power capacity with a linear mixed-integer Matlab optimization model. Furthermore, the operation of for the most optimal technology is simulated for one year with a Model Predictive Control algorithm to be able to compare the effects of forecasting accuracy of the electricity prices on the estimated profits. The results show that according to optimized planning and dispatch in the operation of a battery system can lead to financial opportunities in the Netherlands regarding energy arbitrage for flow batteries. If not today, then in the future. It has been shown that towards 2030 the business case for battery energy storage will significantly increase due to decreasing capital costs and increasing price volatility with the rise of the VRES and phase-out of fossil energy sources. With this research, a contribution is delivered towards the realisation of commercially operating an independent utility-scale battery energy storage facility. Insights are provided on what battery configuration is best suited for energy arbitrage purposes and the effectiveness of simulating the optimized operation of a battery facility with a model predictive control method has been shown. This has lead to clearer insights into the profitability of operating a BESF in the Netherlands.Electrical Engineering | Sustainable Energy Technolog
A Systematic LCA-enhanced KPI Evaluation towards Sustainable Manufacturing in Industrial Decision-making Processes. A Case Study in Glass and Ceramic Frits Production
No full textAbstractTechnologies are difficult to assess in an early stage of development. A comparison between innovative and conventional technologies is often complex due to differences in scale (large-scale with several 100 t/d vs. demonstrator-scale with less than 100kg/d) and subsequent efficiency. A methodology is implemented using Key Performance Indicators (KPIs) enhanced by Life Cycle Assessment (LCA) aspects and incorporating industrial principles for technology assessment. The methodology is applied to identify the trade-off between direct and indirect emissions and to evaluate scale dependency with focus on energy and broader sustainability. The applicability is illustrated for glass and ceramic frits production and supported by experimental data for conventionally and innovatively heated processes
Perceived versus actual quality in student-centered statistics education
No full textstatus: Publishe
Vastgoed reëel
No full textMet ingang van 1 oktober 1999 heeft Frits Seijffert, hoogleraar Bouweconomie bij de faculteit Bouwkunde van de Technische Universiteit Delft, zijn functie neergelegd vanwege het bereiken van de pensioengerechtigde leeftijd. Zijn afscheid was aanleiding voor het samenstellen van dit boek met de titel 'Vastgoed Reëel'. Dit boek bevat een aantal artikelen van Frits Seijffert, waaronder zijn inaugurele rede die nog niet eerder gepubliceerd werd. Daarnaast bevat dit boek enkele artikelen die hij samen met zijn collegae schreef en een aantal artikelen die zijn geschreven door vakgenoten, collegae en oud-afstudeerders van Frits Seijffert. Als laatste artikel is zijn afscheidstoespraak opgenomen, die hij heeft uitgesproken op 22 oktober 1999, tijdens het minisymposium met het thema 'Op de lange duur bezien', dat ter gelegenheid van zijn afscheid werd georganiseerd. Dit boek werd tijdens dit minisymposium in de publiciteit gebracht en na afloop uitgereikt aan de aanwezigen. Dit boek geeft een beeld van de werkzaamheden en de (financiële) benaderingswijze van Frits Seijffert. De andere auteurs reageren in hun bijdrage direct of indirect op zijn benaderingswijze of lichten hun eigen benaderingswijze toe. Zeer veel dank aan allen die aan dit boek hebben bijgedragen. De betekenis van Frits voor zijn vakgebied is groot, al is dit niet in talloze publicaties na te lezen. Frits Seijffert heeft publiceren nooit als doel gezien, maar als middel om zijn benaderingswijze, mening of oplossing te ventileren. En dat deed hij veelvuldig, meestal in de vorm van artikelen. Een selectie hieruit is in dit boek terug te vinden. Uit deze artikelen komt een scherpzinnige vakman tevoorschijn, die zijn zienswijze illustreert met legio voorbeelden. Voor velen zal het herinneringen oproepen aan een vriend, collega of vakgenoot die ook om zijn eigen - zo typerende - manier van schrijven en redeneren zeer gewaardeerd is. Namens de afstudeerrichting Bouwmanagement & Vastgoedbeheer, Prof. ir. Hans de Jonge hoogleraar VastgoedbeheerArchitectur
[Rezension von:] Mulder, Bertus; Rook, Gerrit Jan de: Rietveld-Schröderhuis 1925 - 1975. - Utrecht , 1975
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