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El aumento espectacular y sin precedentes de las llamadas células solares de perovskita (PSC) en la eficiencia de conversión con procesos de fabricación de bajo costo ha llamado la atención de la comunidad científica en el campo de la energía fotovoltaica durante los últimos cuatro años. La inclusión de materiales absorbentes de tipo perovskita, típicamente CH 3 NH 3 PbI 3 , ha sido el factor clave para el desarrollo de esta tecnología emergente que ha creado muchas expectativas. Sin embargo, muchos aspectos poco conocidos de sus modos de operación aún necesitan explicaciones confiables. Este documento proporciona una breve introducción a la estructura, materiales y características de las PSC. Además, se proporcionan algunos comentarios sobre la estabilidad de estos dispositivos y se discute el estado del arte de varios temas de interés, como el fenómeno de histéresis de las curvas de corriente-voltaje. L'augmentation spectaculaire et sans précédent de l'efficacité de conversion des cellules solaires dites pérovskites (CSP) avec des procédés de fabrication à faible coût a attiré l'attention de la communauté scientifique dans le domaine du photovoltaïque au cours des quatre dernières années. L'inclusion de matériaux absorbants de type pérovskite, typiquement CH 3 NH 3 PbI 3 , a été le facteur clé pour le développement de cette technologie émergente qui a créé beaucoup d'attentes. Cependant, de nombreux aspects mal compris de ses modes de fonctionnement ont encore besoin d'explications fiables. Cet article fournit une brève introduction à la structure, aux matériaux et aux caractéristiques des CSP. En outre, quelques remarques sur la stabilité de ces dispositifs sont fournies et l'état de l'art de plusieurs sujets d'intérêt est discuté, tels que le phénomène d'hystérésis des courbes courant-tension. The spectacular and unprecedented rise of so-called perovskite solar cells (PSCs) in conversion efficiency with low-cost manufacturing processes has grabbed the attention of the scientific community in the field of photovoltaics during the last four years.The inclusion of perovskite type absorber materials, typically CH 3 NH 3 PbI 3 , has been the key factor for the development of this emerging technology that has created a lot of expectations.However, many poorly understood aspects of its operating modes still need of reliable explanations.This paper provides a brief introduction to the structure, materials and characteristics of PSCs.In addition, some remarks about the stability of these devices are provided and the state-of-the-art of several subjects of interest is discussed, such as the hysteresis phenomenon of current-voltage curves. استحوذ الارتفاع المذهل وغير المسبوق لما يسمى بالخلايا الشمسية البيروفسكيتية (PSCs) في كفاءة التحويل مع عمليات التصنيع منخفضة التكلفة على اهتمام المجتمع العلمي في مجال الخلايا الكهروضوئية خلال السنوات الأربع الماضية. كان إدراج مواد امتصاص من نوع البيروفسكيت، عادةً CH 3 NH 3 PbI 3 ، هو العامل الرئيسي لتطوير هذه التكنولوجيا الناشئة التي خلقت الكثير من التوقعات. ومع ذلك، لا تزال العديد من الجوانب غير المفهومة لأوضاع تشغيلها بحاجة إلى تفسيرات موثوقة. توفر هذه الورقة مقدمة موجزة لهيكل ومواد وخصائص PSC. بالإضافة إلى ذلك، يتم تقديم بعض الملاحظات حول استقرار هذه الأجهزة ومناقشة أحدث ما توصلت إليه العديد من الموضوعات المثيرة للاهتمام، مثل ظاهرة التباطؤ في منحنيات الجهد الحالي.

A five-foot-diameter, spherical, thin-walled, steel shell, simulating a nuclear reactor outer containment vessel, was lined with three different shock absorbing materials and subjected to internal blast loading from Pentolite explosive charges. Strain-time histories of shell response were measured with strain gages on the shell's outer surface. Peak strains generated in the lined shells were approximately one-half those recorded with the same shell when unlined. The results suggest the feasibility of increasing the blast resistance of outer containment vessels of nuclear reactors through the use of a suitable lining material. (Author). ; Department of the Army project no. 503-04-002. ; "April 1961" ; BRL-1341 ; A five-foot-diameter, spherical, thin-walled, steel shell, simulating a nuclear reactor outer containment vessel, was lined with three different shock absorbing materials and subjected to internal blast loading from Pentolite explosive charges. Strain-time histories of shell response were measured with strain gages on the shell's outer surface. Peak strains generated in the lined shells were approximately one-half those recorded with the same shell when unlined. The results suggest the feasibility of increasing the blast resistance of outer containment vessels of nuclear reactors through the use of a suitable lining material. (Author). ; Mode of access: Internet.

The recent trend of increasing share of renewable energy sources (RES) in the generation mix has necessitated new operational and planning studies because of the high degree of uncertainty and variability of these sources. RES such as solar photovoltaic and wind generation are not dispatchable, and when there is excess energy supply during off-peak hours, RES curtailment is required to maintain the demand-supply balance. Furthermore, RES are intermittent resources which have introduced new challenges to the provision of ancillary services that are critical to maintaining the operational reliability of power systems. Energy storage systems (ESS) play a pivotal role in facilitating the integration of RES to mitigate the aforementioned issues. Therefore, there is a growing interest in recent years to examine the potential of ESS in the future electricity grids. This research focuses on developing market participation and investment planning frameworks for ESS considering different ownership structures. First, a novel stochastic planning framework is proposed to determine the optimal battery energy storage system (BESS) capacity and year of installation in an isolated microgrid using a novel representation of the BESS energy diagram. A decomposition-based approach is proposed to solve the problem of stochastic planning of BESS under uncertainty. The optimal decisions minimize the net present value of total expected costs over a multi-year horizon considering optimal BESS operation using a novel matrix representing BESS energy capacity degradation. The proposed approach is solved in two stages as mixed integer linear programming (MILP) problems; the optimal ratings of the BESS are determined in the first stage, while the optimal installation year is determined in the second stage. Extensive studies considering four types of BESS technologies for deterministic, Monte Carlo Simulations, and stochastic cases are presented to demonstrate the effectiveness of the proposed approach. The thesis further studies the ...

Introduction: Wind turbines are a source of renewable energy that has become more common in Canada in the past decades. Concerns have been raised over potential adverse health effects from exposure to wind turbines, particularly wind turbine noise. A disagreement exists over the potential harm from exposure to wind turbines to human health, where many public health organizations state that there are no direct human health impacts from wind turbine exposure, while many community groups state that wind turbines are harmful to human health. Objectives: 1. Determine the types of evidence cited by community group websites, and by public health organization websites, to support their respective positions on the potential health effects of wind turbines; and 2. Assess the pattern of citations or links to the evidence used by community groups and public health organizations to characterize and interpret these patterns of evidence citation and to see whether and how these patterns differ between the two groups. Methods: Websites of Canadian community groups, public health organizations, environmental non-governmental organizations (eNGOs) and academic organizations were identified using an Internet search strategy. The identified websites with content on wind turbines and human health that met the inclusion criteria were characterised with a data collection tool to gather information about the webpage structure and its links to evidence sources and other organizations’ websites. Descriptive statistical analysis was performed on the website characteristics and evidence and organization citation data. Testing for significant differences between community groups and public health organizations was done using t-tests and chi-squared tests. Adjacency matrices were created to represent the presence of ties between organization websites and between organization websites and evidence sources. Graphs (sociograms) were created based on the adjacency matrices to visualise the relationship between the different types of ...

Item 434-A-10 ; "FEA/D-75/629." ; Prepared by Jim Rathwell and Gwendolyn Gales. ; Mode of access: Internet.

In the series University of Florida Digital Collections. ; Includes vita. ; (Bibliography) Includes bibliographical references. ; (Source of Description) Description based on online resource; title from PDF title page. ; (Source of Description) This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law. ; (Statement of Responsibility) by Douglas Renk. ; (Thesis) Thesis (M.S.)--University of Florida, 2009. ; (Local) Adviser: Pullammanappallil, Pratap C.

text ; This dissertation examines the application of various classical root finding methods to digital maximum power point tracking (DMPPT). An overview of root finding methods such as the Newton Raphson Method (NRM), Secant Method (SM), Bisection Method (BSM), Regula Falsi Method (RFM) and a proposed Modified Regula Falsi Method (MRFM) applied to photovoltaic (PV) applications is presented. These methods are compared among themselves. Some of their features are also compared with other commonly used maximum power point (MPP) tracking methods. Issues found when implementing these root finding methods based on continuous variables in a digital domain are explored. Some of these discussed issues include numerical stability, digital implementation of differential operators, and quantization error. Convergence speed is also explored. The analysis is used to provide practical insights into the design of a DMPPT based on classical root finding algorithms. A new DMPPT based on a MRFM is proposed and used as the basis for the discussion. It is shown that this proposed method is faster than the other discussed methods that ensure convergence to the MPP. The discussion is approached from a practical perspective and also includes theoretical analysis to support the observations. Extensive simulation and experimental results with hardware prototypes verify the analysis. ; Electrical and Computer Engineering

The objective of the study is to: (i) assess the adequacy of the existing heat and electricity tariff levels for achieving financial viability of the energy sector operators; (ii) analyze the distributional implications of energy tariff increases; and (iii) assess the effectiveness of the existing social assistance programs and how to adjust them to mitigate the impact of energy tariff increase on the poor This report presents the key findings and recommendations for the Government of Moldova as well as other energy sector stakeholders. The report starts with a synopsis that summarizes the key findings and recommendations. The main report section starts with an introduction to country context, presents the design of tariff setting methodologies, and assesses the adequacy of tariffs based on constructed scenarios. Thereafter analysis of the distributional impact of projected range of tariff increases and the need to adjust the social assistance programs to mitigate the impact on the poor are presented. The report concludes with recommendations for the government on actions to be implemented on tariff setting methodologies and social assistance as well as areas for further research. Appendices include further background information of the analysis.

采用共沉淀法合成磁性Fe_3O_4,通过碳化磺化制备核壳结构的磁性固体酸催化剂Fe_3O_4/C-SO_3H,并利用透射电子显微镜(TEM)、傅里叶变换红外光谱仪(FT-IR)、X射线衍射(XRD)、振动样品磁强计(VSM)、元素分析等手段对催化剂特性进行表征分析。以催化玉米芯水解所得的木糖得率为评价指标,对磁性固体酸催化剂催化玉米芯水解工艺条件进行优化研究,得出最佳条件为反应时间10 h、反应温度140 ℃、催化剂用量1.5 g、固液比(g/mL)2∶50(玉米芯含量为0.5 g),此时木糖得率为51.01%。研究认为,磁性固体酸催化剂催化木质纤维素水解的反应过程为酸催化和吸附过程共同作用,木质纤维素是分级解聚逐步转化,利用两步操作能够最大程度的水解木质纤维素。

"Issued December 1980." ; "Building Economics and Regulatory Technology Division, Center for Building Technology, National Engineering Laboratory, National Bureau of Standards." ; Includes bibliographical references. ; Mode of access: Internet.