Suitability of Reduced Part Count Multilevel Inverter Topologies for Grid Interfacing

2016 ◽  
Vol 25 (07) ◽  
pp. 1650081 ◽  
Author(s):  
Rekha Agrawal ◽  
Shailendra Jain
Keyword(s):  
Wide Spectrum ◽  
Renewable Energy Sources ◽  
Circuit Complexity ◽  
Emerging Technology ◽  
Future Research ◽  
Multilevel Inverters ◽  
Advantages And Disadvantages ◽  
Input Source ◽  
And Performance

Reduced part count multilevel inverters (RPC-MLIs), an emerging technology for grid interfacing applications of renewable energy sources. RPC-MLIs overcome the limitations of conventional two-level and classical multilevel inverters (NPC, FC and CHB) by the use of reduced part counts for generation of same number of levels in the output. Focus of this paper is on to present review of the RPC-MLIs for researchers and engineers and classification of all the topologies. RPC-MLIs are compared considering its circuit complexity and performance. The comparison exposes advantages and disadvantages of topologies, as well as a wide spectrum for future research. This paper also draws the most potential topology in the field of grid integrated applications. Promising topology is simulated here under the same load and input source condition using real time simulator.

scholarly journals VERSLO ORGANIZACIJŲ KLIMATO ĮVERTINIMO GALIMYBĖS

Psichologija ◽  
2005 ◽  
Vol 31 ◽  
pp. 86-100
Author(s):  
Rita Rekašiūtė-Balsienė
Keyword(s):  
Organizational Climate ◽  
Organizational Performance ◽  
Organizational Development ◽  
Wide Spectrum ◽  
Work Organization ◽  
Working Environment ◽  
Future Research ◽  
Climate Assessment ◽  
And Performance ◽  
Business Departments

Daugelio tyrimų rezultatai rodo, kad organizacijos klimatas ir jos veiklos rezultatai yra susiję. Organizacijos klimato matavimas gali būti atspirties taškas planuojant veiklos tobulinimo, siekiant didesnio efektyvumo, pokyčius. Straipsnyje pristatytos trys organizacijos klimato teorijų grupės ir atliktas tyrimas, siekiant aprašyti Lietuvos verslo organizacijų klimatą. Tyrimo tikslas – įvertinti Lietuvos verslo organizacijų klimatą taikant tam sukurtą metodiką. Tyrimui keliami uždaviniai: 1) parengti organizacijos klimato vertinimo metodiką; 2) išanalizuoti organizacijos klimato ypatybes, būdingas Lietuvos verslo organizacijoms. Gauti rezultatai rodo, kad Lietuvos verslo organizacijų klimatas turi bendrų ypatumų: geriausiai yra vertinama organizacijos svarba darbuotojams (didžiavimasis organizacija), darbuotojų pastangos ir tarpusavio santykiai bei pagarba, o blogiausiai – darbuotojų veiklos ir pastangų įvertinimas bei darbo organizavimas. Sukurta metodika patikrinta tiriant Lietuvos verslo organizacijas. Ji leidžia įvertinti bei aprašyti organizacijos klimatą ir gali būti pagrindas aiškinantis, kokia yra organizacijos būklė. ORGANIZATIONAL CLIMATE ASSESSMENT POSSIBILITIES IN BUSINESS ORGANIZATIONSRita Rekašiūtė-Balsienė SummaryOrganizational climate has been widely discussed in the literature since the concept of social climate was proposed. They perceived organizational climate as a set of properties of the working environment which can be measured. In the article we present three set of theories of organizational climate concepts, which were found in the literature.The wide spectrum of organizational climate and performance surveys suggests that there are relationship between the climate dimensions and all kind of organizational performance indicators. It is suggested, that for a plan of activities for improving effectiveness of all organization may be used climate surveys.The purpose of this survey is to evaluate organizational climate is Lithuanian business organizations using the questionnaire which was created by the author of the article.Sample: 6 Lithuanian organizations from the service business sector, total of 591 employees. All organizations are among the firs seventh leaders of their practice field.Method: Organizational climate questionnaire (constructed by author of the article) was used in this survey. Factorial analysis distinguishes eight factors (scales): evaluations of employee attempts and performance; interrelations and respect; flexibility and quality of organization performance; employee struggle; goals knowledge; organization magnitude; cooperation; work organization. The research has been carried out in 2003–2004.Results of this survey shows, that all organizations have common peculiarities of organizational climate. Perceived as the best organizational climate aspects are organization magnitude, employee struggle, interrelations and respect; perceived as the worst organizational climate aspects are evaluation of employee attempts and performance and work organization. There was found significant differences in perceived organization conditions between managers and employees and between business departments and business support departments, what request more in depth survey. Organizational climate of two organizations are described in detail. It is suggested, that created questionnaire can be used to asses organizational climate and be useful tool for the organizational development practitioner and researcher. Practical implications and suggestions for future research are proposed.

scholarly journals A critical review on the development and performance of polymer/graphene nanocomposites

2018 ◽  
Vol 25 (6) ◽  
pp. 1059-1073 ◽  
Author(s):  
Weifeng Chen ◽  
Hu Weimin ◽  
Dejiang Li ◽  
Shaona Chen ◽  
Zhongxu Dai
Keyword(s):  
Polymer Nanocomposites ◽  
Electronic Conductivity ◽  
Future Research ◽  
Preparation Methods ◽  
Graphene Nanocomposites ◽  
Advantages And Disadvantages ◽  
Solution Blending ◽  
Potential Applications ◽  
New Type ◽  
And Performance

AbstractGraphene (graphene) is a new type of two-dimensional inorganic nanomaterial developed in recent years. It can be used as an ideal inorganic nanofiller for the preparation of polymer nanocomposites because of its high mechanical strength, excellent electrical conductivity and plentiful availability (from graphite). In this review, the preparation methods of graphene/polymer nanocomposites, including solution blending, melt blending and in situ polymerization, are introduced in order to study the relationship between these methods and the final characteristics and properties. Each method has an influence on the final characteristics and properties of the nanocomposites. The advantages and disadvantages of these methods are discussed. In addition, a variety of nanocomposites with different properties, such as mechanical properties, electronic conductivity, thermal conductivity and thermal properties, are summarized comprehensively. The potential applications of these nanocomposites in conductive materials, electromagnetic shielding materials, photocatalytic materials and so on, are briefly presented. This review demonstrates that polymer/graphene nanocomposites exhibit superior comprehensive performance and will be applied in the fields of new materials and novel devices. Future research directions of the nanocomposites are also presented.

scholarly journals River Channel Relocation: Problems and Prospects

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1360 ◽  
Author(s):  
Alissa Flatley ◽  
Ian Rutherfurd ◽  
Ross Hardie
Keyword(s):  
Ecological Impacts ◽  
Future Research ◽  
Erosion And Deposition ◽  
Channel Change ◽  
Specific Category ◽  
Wide Range ◽  
Key Issues ◽  
And Performance ◽  
Vegetation Loss

River relocation is the diversion of a river into an entirely new channel for part of their length (often called river diversions). Relocations have been common through history and have been carried out for a wide range of purposes, but most commonly to construct infrastructure and for mining. However, they have not been considered as a specific category of anthropogenic channel change. Relocated channels present a consistent set of physical and ecological challenges, often related to accelerated erosion and deposition. We present a new classification of river relocation, and present a series of case studies that highlight some of the key issues with river relocation construction and performance. Primary changes to the channel dimensions and materials, alongside changes to flow velocity or channel capacity, can lead to a consistent set of problems, and lead to further secondary and tertiary issues, such as heightened erosion or deposition, hanging tributaries, vegetation loss, water quality issues, and associated ecological impacts. Occasionally, relocated channels can suffer engineering failure, such as overtopping or complete channel collapse during floods. Older river relocation channels were constructed to minimise cost and carry large floods, and were straight and trapezoidal. In some countries, modern relocated channels represent an exciting new challenge in that they are now designed to replicate natural rivers, the success of which depends on understanding the characteristics, heterogeneity, and mechanisms at work within the natural channel. We discuss shortcomings in current practice for river relocation and highlight areas for future research for successful rehabilitation of relocated rivers.

scholarly journals Current overview of carbon fiber: Toward green sustainable raw materials

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 7234-7259
Author(s):  
Yongjian Xu ◽  
Yan Liu ◽  
Shenglin Chen ◽  
Yonghao Ni
Keyword(s):  
Carbon Fiber ◽  
Carbon Fibers ◽  
Melt Spinning ◽  
Raw Materials ◽  
Future Research ◽  
Process Conditions ◽  
Preparation Methods ◽  
Advantages And Disadvantages ◽  
Solution Spinning ◽  
And Performance

Lignin, as a potential precursor of carbon fiber, has the characteristics of abundant reserves, renewable and high carbon content, and its application in the preparation of carbon fibers has substantial cost advantages if some important processing and quality hurdles can be overcome. This paper reviews the preparation process of lignin-based carbon fibers, and moreover, describes the characteristics of carbon fiber prepared by different precursors compared with the presently used precursors. Three preparation methods for lignin-based carbon fibers are introduced: melt spinning, solution spinning, and electrospinning. The applicability, advantages, and disadvantages of the three preparation methods are analyzed from the aspects of process conditions and performance characteristics. Possible directions for future research are considered, with the goal of providing a reference for further study of lignin-based carbon fibers.

scholarly journals Artificial Intelligence Techniques for Power System Transient Stability Assessment

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 507
Author(s):  
Petar Sarajcev ◽  
Antonijo Kunac ◽  
Goran Petrovic ◽  
Marin Despalatovic
Keyword(s):  
Artificial Intelligence ◽  
Power System ◽  
Power Plants ◽  
Transient Stability ◽  
Model Building ◽  
Renewable Energy Sources ◽  
Optimization Techniques ◽  
Future Research ◽  
Stability Assessment ◽  
Advantages And Disadvantages

The high penetration of renewable energy sources, coupled with decommissioning of conventional power plants, leads to the reduction of power system inertia. This has negative repercussions on the transient stability of power systems. The purpose of this paper is to review the state-of-the-art regarding the application of artificial intelligence to the power system transient stability assessment, with a focus on different machine, deep, and reinforcement learning techniques. The review covers data generation processes (from measurements and simulations), data processing pipelines (features engineering, splitting strategy, dimensionality reduction), model building and training (including ensembles and hyperparameter optimization techniques), deployment, and management (with monitoring for detecting bias and drift). The review focuses, in particular, on different deep learning models that show promising results on standard benchmark test cases. The final aim of the review is to point out the advantages and disadvantages of different approaches, present current challenges with existing models, and offer a view of the possible future research opportunities.

scholarly journals Quantitative Analysis and Performance Evaluation of Target-Oriented Replication Strategies in Cloud Computing

Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 672
Author(s):  
Quadri Waseem ◽  
Wan Isni Sofiah Wan Din ◽  
Sultan S. Alshamrani ◽  
Abdullah Alharbi ◽  
Amril Nazir
Keyword(s):  
Cloud Computing ◽  
Performance Evaluation ◽  
Quantitative Analysis ◽  
Performance Indicator ◽  
Data Replication ◽  
Future Research ◽  
Dynamic Data ◽  
Advantages And Disadvantages ◽  
Dynamic Data Replication ◽  
And Performance

Data replications effectively replicate the same data to various multiple locations to accomplish the objective of zero loss of information in case of failures without any downtown. Dynamic data replication strategies (providing run time location of replicas) in clouds should optimize the key performance indicator parameters, like response time, reliability, availability, scalability, cost, availability, performance, etc. To fulfill these objectives, various state-of-the-art dynamic data replication strategies has been proposed, based on several criteria and reported in the literature along with advantages and disadvantages. This paper provides a quantitative analysis and performance evaluation of target-oriented replication strategies based on target objectives. In this paper, we will try to find out which target objective is most addressed, which are average addressed, and which are least addressed in target-oriented replication strategies. The paper also includes a detailed discussion about the challenges, issues, and future research directions. This comprehensive analysis and performance evaluation based-work will open a new door for researchers in the field of cloud computing and will be helpful for further development of cloud-based dynamic data replication strategies to develop a technique that will address all attributes (Target Objectives) effectively in one replication strategy.

Study on Hub Location Models and Research Trends

2014 ◽  
Vol 505-506 ◽  
pp. 528-532
Author(s):  
Meng Liang Li ◽  
Xi Fu Wang ◽  
Quan Xin Sun
Keyword(s):  
Mathematical Models ◽  
Research Trends ◽  
Future Research ◽  
Hub Location ◽  
Hub Location Problem ◽  
Theoretical Concepts ◽  
Advantages And Disadvantages ◽  
Resolution Algorithm ◽  
Fertile Area

Hub location has been a fertile area for interdisciplinary researchers. There has been used to plan the number of hubs, position, grades, scale and so on. Many scholars have studied hub location problem for more than 30-year history which has indepth researched on the theoretical concepts, mathematical models and applications in hub location. For the development of hub location, a review of classification of HLPs is provided, and then mathematical models, resolution algorithm, the advantages and disadvantages of each classification could be described in detail. At the end, the future research trends will be presented.

Methods for determination of labile soil organic matter: An overview

2010 ◽  
Vol 27 (2) ◽  
pp. 49-60 ◽  
Author(s):  
Eduard Strosser
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Analytical Methods ◽  
Wide Spectrum ◽  
Future Research ◽  
Soil Productivity ◽  
Advantages And Disadvantages ◽  
Functional Characterisation ◽  
Labile Soil Organic Matter

Methods for determination of labile soil organic matter: An overviewSoil organic matter (SOM) can be divided into three main pools: labile, stable and inert. Research over recent years has focused on the labile fraction (LF), as it is considered a quickly reactive indicator of soil productivity and health, and important as a supply of energy for soil micro-organisms. A wide spectrum of analytical methods has been used to determine and/or evaluate LF, based on physical, chemical and biochemical principles. The advantages and disadvantages of each technique are explored in this work, but none of the methods can determine LF sufficiently, either because a part of the LF is not involved or because further characterisation is missing. Although analytical methods are widely used to evaluate changes in soil management or organic carbon turnover, the practical question of the quantity and quality of SOM cannot be answered completely. It is also suggested that future research should focus on the interactions among SOM fractions and their better chemical and functional characterisation. It is possible to use a combination of the analytical methods reviewed here in order to accomplish this objective.

MODERN EQUIPMENT FOR DETERMINING TRACTOR-SPEED PROPERTIES OF THE VEHICLE: CHARACTERISTICS’ ANALYSIS IN LABORATORY CONDITIONS

2019 ◽  
Vol 16 (3) ◽  
pp. 276-289
Author(s):  
N. V. Savenkov ◽  
V. V. Ponyakin ◽  
S. A. Chekulaev ◽  
V. V. Butenko
Keyword(s):  
Environmental Performance ◽  
Operating Conditions ◽  
Special Role ◽  
Development Stages ◽  
Advantages And Disadvantages ◽  
Force Transfer ◽  
Characteristics Analysis ◽  
And Performance ◽  
Loading Devices ◽  
Structural Solutions

Introduction. At present, stands with running drums are widely used for various types of tests. Power stands play a special role. Such stands take the mechanical power from the driving wheels of the car. This simulates the process of movement of the vehicle under operating conditions. Such equipment has various designs, principles of operation and performance. It is also used in tests that are different by purpose, development stages and types: research, control, certification, etc. Therefore, it is necessary in order to determine the traction-speed, fuel-efficient and environmental performance characteristics.Materials and methods. The paper provides the overview of the power stands with running drums, which are widespread on the domestic market. The authors carried out the analysis of the main structural solutions: schemes of force transfer between the wheel and the drum; types of loading devices; transmission layout schemes and features of the control and measuring complex. The authors also considered corresponding advantages and disadvantages, recommended spheres of application, demonstrated parameters and characteristics of the units’ workflow, presented components and equipment.Discussion and conclusions. The authors critically evaluate existing models of stands with running drums. Such information is useful for choosing serial models of stands and for developing technical tasks for designing or upgrading the equipment.

Alpine vegetation of the Ivanovskiy, Prokhodnoy and Rossypnoy Ridges (Western Altai)

2015 ◽  
pp. 96-124
Author(s):  
E. G. Zibzeev ◽  
T. A. Nedovesova
Keyword(s):  
Plant Communities ◽  
Wide Spectrum ◽  
Climate Forcing ◽  
High Mountain ◽  
Air Mass ◽  
Rich Diversity ◽  
Mountain Systems ◽  
Mountain Vegetation ◽  
Coenotic Diversity

The mountain systems are characterized by diverse ecological conditions (climate, geomorphological, soil, etc.). The wide spectrum of environmental conditions entails a rich diversity of plant communities growing on the small territory and determines the different flora and vegetation geneses. The uniqueness of floristic and coenotic diversities of the high-mountain vegetation of the south of Western Altai (Ivanovskiy, Prokhodnoi, and Rossypnoi Ranges) are associated with the effect of two climate-forcing factors such as the westerly humid air mass and dry warm airflow from the inner Kazakhstan regions. The paper summarizes the data on coenotic diversity (Zibzeev, 2010, 2012) and gives a syntaxonomic analysis of the high-mountain vege­tation in the Ivanovskii, Prokhodnoi, and Rossypnoi Ranges (Western Altai, Kazakhstan). The classification of plant communities was carried out using the Braun-Blanquet approach (Westhoff, van der Maarel, 1973). The relevés records were stored in the TURBOVEG database and classified by ­TWINSPAN (Hill 1979).

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