Reliability-based optimized design of hybrid tether

2020 ◽  
Vol 92 (8) ◽  
pp. 1141-1147
Author(s):  
Anil Kumar Agrawal ◽  
Mahendra Pratap ◽  
Subhash Chandra Sati ◽  
Rajeev Kumar Upadhyay
Keyword(s):  
Probabilistic Approach ◽  
Population Data ◽  
Operational Reliability ◽  
Design Approach ◽  
Optimized Design ◽  
Limited Data ◽  
Content Type ◽  
Reliability Based Design ◽  
Classical Design ◽  
Sample Test

Purpose The purpose of this paper is to optimize the design of a hybrid tether using probabilistic approach considering inherent random variation in the stress developed and the strength it has. The variation in strength is mostly because of variation in diameter of the tether and the properties of the material along the length of the tether. As a result, classical design approach for the tether may not serve the purpose. For this purpose, a reliability-based design of hybrid tether is discussed in this paper. Design/methodology/approach A literature review was carried out on the design of tether and its operational reliability. It has been shown that the classical design approach does not serve the purpose, as the strategic operation has to be reliable enough, often requiring a measure of reliability required. A reliability-based approach has been presented to achieve the optimum design of a hybrid tether. Findings The optimization problem was carried out for different values of the safety factor to investigate the effect on the optimal design of tether. An analysis is carried out to show that one should not target a very high value of reliability or factor of safety, as it causes the self-weight of the tether to increase tremendously and its cost significantly. Research limitations/implications The present work has been carried out considering the limited data and can further be extended to determine more accurate reliability measures by considering more number of sample test data. The measured data is collected from limited required trials for demo; do not represent the exact population data. Originality/value Lab strength test and flight trials were conducted to acquire data for the present analysis. In field use, it was noticed that the tether degraded from top portion attached toward the balloon end because of maximum exposure and repeated usage.

Design Nomographs of Compression Helical Springs for Predetermined Reliability Levels

1981 ◽  
Vol 103 (2) ◽  
pp. 268-273
Author(s):  
My Dao Thien ◽  
M. Massoud
Keyword(s):  
Probabilistic Approach ◽  
Design Procedure ◽  
Axial Loading ◽  
Geometric Parameters ◽  
Computer Algorithms ◽  
Mean Values ◽  
Helical Springs ◽  
Reliability Level ◽  
Classical Design ◽  
Mission Success

This paper discusses a probabilistic approach for the design of Compression Closely Coiled Helical Springs subjected to periodic axial loading. The classical design procedure results in deterministic geometric parameters with tolerances normally chosen according to standards without due regard to their effects on the mission success as normally expressed by a reliability level. With the proposed design procedure, the engineer can specify nominal mean values for the geometric parameters and their tolerances according to a predetermined reliability level. Design nomographs are presented to help the engineer, in the early stages of design, to choose between many alternatives. Computer algorithms can easily be written to verify the final or optimum design.

Investigation of slip/no-slip surface for two-dimensional large tilting pad thrust bearing

2017 ◽  
Vol 69 (6) ◽  
pp. 995-1004 ◽  
Author(s):  
Zhixiang Song ◽  
Fei Guo ◽  
Ying Liu ◽  
Songtao Hu ◽  
Xiangfeng Liu ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Slip Surface ◽  
Load Capacity ◽  
Slip Condition ◽  
Optimized Design ◽  
Two Dimensional ◽  
Boundary Slip ◽  
Content Type ◽  
Tilting Pad ◽  
Turbulence Effect

Purpose This paper aims to present the slip/no-slip design in two-dimensional water-lubricated tilting pad thrust bearings (TPTBs) considering the turbulence effect and shifting of pressure centers. Design/methodology/approach A numerical model is established to analyze the slip condition and the effect of turbulence according to a Reynolds number defined in terms of the slip condition. Simulations are carried out for eccentrically and centrally pivoted bearings and the influence of different slip parameters is discussed. Findings A considerable enhancement in load capacity, as well as a reduction in friction, can be achieved by heterogeneous slip/no-slip surface designs for lubricated sliding contacts, especially for near parallel pad configurations. The optimized design largely depends on the pivot position. The load capacity increases by 174 per cent for eccentrically pivoted bearings and 159 per cent for centrally pivoted bearings for a suitable design. When slip zone locates at the middle of the radial direction or close to the inner edge, the performance of the TPTB is better. Research limitations/implications The simplification of slip effect on the turbulence (definition of Reynolds number) can only describe the trend of the increasing turbulence due to slip condition. The accurate turbulence expression considering the boundary slip needs further explorations. Originality/value The shifting of pressure center due to the slip/no-slip design for TPTBs is investigated in this study. The turbulence effect and influence of slip parameters is discussed for large water-lubricated bearings.

Knowledge management implementation in Indian automobile ancillary industries

2016 ◽  
Vol 11 (3) ◽  
pp. 802-810 ◽  
Author(s):  
Nitin Yashwant Patil ◽  
Ravi M. Warkhedkar
Keyword(s):  
Knowledge Management ◽  
Industrial Area ◽  
Total Quality ◽  
Limited Data ◽  
Interpretive Structural Modeling ◽  
Content Type ◽  
Relationship Of ◽  
Power And Dependence ◽  
The Relationship

Purpose In the past decade, much has been written about knowledge management (KM) in the manufacturing; however, less attention has been paid to the Indian automobile ancillary industries located in Chinchwad, Pune. It is suitable to find out the relationship of the factors of the study. It helps in identifying the hierarchy of factors to be taken, and interlinking of production department with KM improves the productivity of the industries. Categorization of these principles based on their driving power (principles which hold other principles) and dependence (principles which are dependent on other principles) has also been examined for KM implementation to study the driving power and dependence power of these principles. This paper aims to determine the roadmap of KM implementation and categorize KM principles based on their driving power for manufacturing industries with the use of the interpretive structural modeling (ISM)-based model. The results indicate that the principles possessing higher driving power, such as KM, inventory control, quality control, productivity and scheduling and their interlinking. The major contribution of this research lies in the development of contextual relationship among various identified factors of KM and determination of their driving and dependence power through a single systemic framework. Design/methodology/approach In this paper, author find out the suitability ISM for Indian Automobile industries to find the relation among the variables. Findings ISM model has been developed for the hierarchy of the identified KM. As ISM model results a hypothetical hierarchy which needs a proper quantitative analysis to evaluate their percentage effectiveness in the hierarchy. Research limitations/implications It is applied to automobile industries with limited number of variables that will show the dependence variable and driving variables and their interrelations. It can be applied other fields to fine the relationship of variables. Practical implications The ISM may be used in supply chain management and total quality management to find interlinking between the variables. Originality/value The limited data collected from Pimpri Chinchwad industrial area of Pune from Maharashtra state (India).

A design approach for process-based knowledge management systems

2017 ◽  
Vol 21 (4) ◽  
pp. 693-717 ◽  
Author(s):  
Surendra Sarnikar ◽  
Amit V. Deokar
Keyword(s):  
Knowledge Management ◽  
Feasibility Study ◽  
Systems Analysis ◽  
Design Theory ◽  
Systems Design ◽  
Design Approach ◽  
Content Type ◽  
Analysis And Design ◽  
Systems Analysis And Design ◽  
Design Techniques

Purpose This paper presents a design approach for process-based knowledge management (PKM) systems that can support knowledge-intensive processes where effective task execution is highly reliant on the knowledge and expertise of participants executing the tasks. The proposed design approach includes design methods and kernel theories governing the design of PKM systems and can also be easily integrated with existing systems analysis and design techniques. Design/methodology/approach The design science research methodology is used to design and develop the artifact which includes the overall PKM design approach. Information systems design theory is used as a high-level framework to develop and structure the design approach. Relevant design methods and behavioral theories are reviewed to identify kernel theories that guide the design and development of PKM systems. The design approach consists of meta-requirements for PKM systems and design processes to achieve the meta-requirements. A feasibility study is conducted to evaluate the feasibility of the proposed approach. Findings The design approach presented in this paper can guide system analysts and system developers in the design of knowledge management systems for supporting knowledge-intensive processes. The paper also includes a comprehensive design theory for PKM systems consisting of meta-requirements and a synthesis of various kernel theories into actionable design procedures. The proposed procedures include knowledge requirements modeling, knowledge flows modeling and knowledge and process performance modeling procedures. The feasibility study indicates that the PKM approach can be more useful and effective than solely using unified modeling language (UML)-based systems analysis and design techniques for the design of PKM systems. Research limitations/implications An implication to information systems design research is the feasibility of developing a specialized design approach that incorporates significant domain knowledge to solve complex information system design problems. An implication to practice is the significant potential to improve productivity and effectiveness of systems analysts and designers in developing PKM systems. A limitation is the small sample size of the feasibility study used to evaluate the ease of use and utility of the design approach. Originality/value The study makes a unique contribution by proposing a design approach that integrates business process and knowledge management considerations. The approach is particularly valuable because of the focus on integration with existing systems analysis and design techniques, thus allowing for easier adoption.

Optimization of the design of the pig launcher-receiver chambers of cleaning and diagnostic tools

2021 ◽  
pp. 460-465
Author(s):  
Илья Александрович Флегентов ◽  
Алексей Викторович Кулешов
Keyword(s):  
Operational Reliability ◽  
Operating Costs ◽  
Diagnostic Tools ◽  
Optimized Design ◽  
Metal Consumption ◽  
Process Diagnostics ◽  
Working Chamber ◽  
Pipeline Inspection ◽  
Main Pipelines ◽  
Applied Design

По результатам проведенного анализа конструктивных решений камер пуска-приема средств очистки и диагностики (КПП СОД), применяемых при технической диагностике и техническом обслуживании магистральных трубопроводов в России и за рубежом, был установлен ряд проблем существующих конструкций, снижающих эксплуатационную надежность данного вида оборудования. Это, в свою очередь, обусловило актуальность задачи оптимизации конструкции КПП СОД, в том числе в части унификации используемых при их изготовлении деталей, увеличения доли заводских изделий. Были приняты решения, обеспечившие комплексный подход к вопросу повышения надежности и ремонтопригодности оборудования - разработана новая конструкция КПП СОД, позволяющая снизить металлоемкость и трудоемкость при изготовлении, сократить эксплуатационные затраты, повысить технологичность и прочностные характеристики. В рамках решения данной задачи выполнены расчетно-теоретические исследования с применением прикладного программного комплекса SIMULIA Abaqus. Надежность оптимизированной конструкции подтверждена результатами испытаний на прочность опытного образца КПП СОД с номинальным диаметром рабочей камеры DN 1000. Разработан типоразмерный ряд КПП СОД усовершенствованной конструкции с номинальными диаметрами рабочей камеры DN 150-1200 для применения на магистральных нефте- и нефтепродуктопроводах. Based on the results of the analysis of the design solutions of launching and receiver stations of pipeline inspection gauges (pig launchers-receivers) used in process diagnostics and maintenance of main pipelines in Russia and abroad, a number of applied design issues was established. This, in turn, led to the relevance of the issue of optimizing the design of pig launchers and receivers, including the unification of parts used in their manufacture, thereby increasing the share of factory-made products. Decisions were made that provided a comprehensive approach to the issue of improving the operational reliability of this type of equipment - a new design of pig launchers and receivers was developed, which allows to reduce production metal consumption and labor intensity, reduce operating costs, increase constructability and reliability. As part of the solution of this issue, computational and theoretical studies using the SIMULIA Abacus software package were carried out. The reliability of the optimized design is confirmed by the results of durability tests of the pig launcher and receiver prototype with the nominal diameter of the working chamber of DN 1000. A dimension range of advanced designs of pig launchers and receivers with nominal working chamber diameters of DN 150-1200 for use in main oil and petroleum product pipelines was developed.

In vitro effectiveness of biapenem against IMP-producing Enterobacteriaceae

2021 ◽  
Vol 70 (10) ◽  
Author(s):  
Kazuyoshi Gotoh ◽  
Makoto Miyoshi ◽  
I Putu Bayu Mayura ◽  
Koji Iio ◽  
Osamu Matsushita ◽  
...  
Keyword(s):  
Therapeutic Option ◽  
Small Data ◽  
Limited Data ◽  
Data Set ◽  
Content Type ◽  
Link Type ◽  
Almost All ◽  
New Treatments ◽  
Time Kill

The options available for treating infections with carbapenemase-producing Enterobacteriaceae (CPE) are limited; with the increasing threat of these infections, new treatments are urgently needed. Biapenem (BIPM) is a carbapenem, and limited data confirming its in vitro killing effect against CPE are available. In this study, we examined the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of BIPM for 14 IMP-1-producing Enterobacteriaceae strains isolated from the Okayama region in Japan. The MICs against almost all the isolates were lower than 0.5 µg ml−1, indicating susceptibility to BIPM, while approximately half of the isolates were confirmed to be bacteriostatic to BIPM. However, initial killing to a 99.9 % reduction was observed in seven out of eight strains in a time–kill assay. Despite the small data set, we concluded that the in vitro efficacy of BIPM suggests that the drug could be a new therapeutic option against infection with IMP-producing CPE.

scholarly journals Are In Vitro Susceptibilities to Azole Antifungals Predictive of Clinical Outcome in the Treatment of Candidemia?

2018 ◽  
Vol 56 (12) ◽  
Author(s):  
Twisha S. Patel ◽  
Peggy L. Carver ◽  
Gregory A. Eschenauer
Keyword(s):  
Invasive Candidiasis ◽  
Randomized Trials ◽  
Published Data ◽  
Murine Models ◽  
Limited Data ◽  
Content Type ◽  
Clinical Breakpoints ◽  
The Impact ◽  
The Relationship

ABSTRACT The purpose of this review is to critically analyze published data evaluating the impact of azole pharmacokinetic and pharmacodynamic parameters, MICs, and Candida species on clinical outcomes in patients with candidemia. Clinical breakpoints (CBPs) for fluconazole and voriconazole, which are used to determine susceptibility, have been defined by the Clinical and Laboratory Standards Institute (CLSI) for Candida species. Studies evaluating the relationship between treatment efficacy and in vitro susceptibility, as well as the pharmacodynamic targets, have been conducted in patients treated with fluconazole for candidemia; however, for species other than Candida albicans and Candida glabrata, and for other forms of invasive candidiasis, data remain limited and randomized trials are not available. Limited data evaluating these relationships with voriconazole are available. While pharmacodynamic targets for posaconazole and isavuconazole have been proposed based upon studies conducted in murine models, CBPs have not been established by CLSI. Fluconazole remains an important antifungal agent for the treatment of candidemia, and data supporting its use based on in vitro susceptibility are growing, particularly for C. albicans and C. glabrata. Further investigation is needed to establish the roles of voriconazole, posaconazole, and isavuconazole in the treatment of candidemia and for all agents in the treatment of other forms of invasive candidiasis.

scholarly journals Knowledge, attitude and practice of municipal solid waste management among highland residents in Northern Thailand

2018 ◽  
Vol 32 (2) ◽  
pp. 123-131 ◽  
Author(s):  
Pussadee Laor ◽  
Yanasinee Suma ◽  
Vivat Keawdounglek ◽  
Anuttara Hongtong ◽  
Tawatchai Apidechkul ◽  
...  
Keyword(s):  
Waste Management ◽  
Pearson Correlation ◽  
Population Data ◽  
Municipal Solid Waste Management ◽  
Municipal Solid Wastes ◽  
Cross Sectional ◽  
Content Type ◽  
Attitudes And Practices ◽  
Msw Management ◽  
Good Level

Purpose Chiang Rai is the northernmost province of Thailand. Municipal solid wastes (MSWs) was generated 430,828.2 ton/y in this area; however, only 24 percent of waste was properly disposed, and 43 percent of waste was properly managed. The purpose of this paper is to explore knowledge, attitudes and practices (KAP) of highland residents in order to provide a basis for the development of waste management in the study area. Design/methodology/approach A cross-sectional study was conducted in Mae Fah Luang district, Thailand, from November 2016 to January 2017. A random sample of 451 respondents constituted the study population. Data were gathered using a structured questionnaire. Pearson Correlation and χ2 were applied to identify the association among variables. Findings Overall, 73 percent of respondents had high level of knowledge; 85 percent of respondents showed neutral attitude; and 59 percent of respondents performed moderate practice on MSW management. The results highlighted that age and education levels were statistically significant associated with KAP levels on MSW management at (p=0.05). Originality/value The respondents who have good knowledge also have a good level of practice; and those who have good attitude also have a good level of practice. Socio-demographic factors and suitable way to promote an effective MSW management should be considered.

A design approach towards sustainable buildings in Algeria

2019 ◽  
Vol 9 (3) ◽  
pp. 229-245
Author(s):  
Sofiane Rahmouni ◽  
Rachid Smail
Keyword(s):  
Energy Consumption ◽  
Simulation Software ◽  
Cold Climate ◽  
Design Approach ◽  
Office Building ◽  
Design Stage ◽  
Building Performance ◽  
Sustainable Buildings ◽  
Content Type ◽  
Efficiency Measures

Purpose The purpose of this paper is to achieve the national strategic agenda’s criteria that aim for accomplishing sustainable buildings by estimating the effects of energy efficiency measures in order to reduce energy consumption and CO2 emission. Design/methodology/approach A design approach has been developed based on simulation software and a modeled building. Therefore, a typical office building is considered for testing five efficiency measures in three climatic conditions in Algeria. This approach is conducted in two phases: first, the analysis of each measure’s effect is independently carried out in terms of cooling energy and heating energy intensities. Then, a combination of optimal measures for each climate zone is measured in terms of three sustainable indicators: final energy consumption, energy cost saving and CO2 emission. Findings The results reveal that a combination of optimal measures has a substantial impact on building energy saving and CO2 emission. This saving can rise to 41 and 31 percent in a hot and cold climate, respectively. Furthermore, it is concluded that obtaining higher building performance, different design alternatives should be adapted to the climate proprieties and the local construction materials must be applied. Originality/value This study is considered as an opportunity for achieving the national strategy, as it may contribute in improving office building performance and demonstrating a suitable tool to assist stakeholders in the decision making of most important parameters in the design stage for new or retrofit buildings.

scholarly journals Online learning behavior analysis based on machine learning

2019 ◽  
Vol 14 (2) ◽  
pp. 97-106
Author(s):  
Ning Yan ◽  
Oliver Tat-Sheung Au
Keyword(s):  
Machine Learning ◽  
Online Learning ◽  
Correlation Analysis ◽  
Prediction Accuracy ◽  
Classification Models ◽  
Limited Data ◽  
Learning Models ◽  
Learning Behavior ◽  
Content Type ◽  
Machine Learning Models

Purpose The purpose of this paper is to make a correlation analysis between students’ online learning behavior features and course grade, and to attempt to build some effective prediction model based on limited data. Design/methodology/approach The prediction label in this paper is the course grade of students, and the eigenvalues available are student age, student gender, connection time, hits count and days of access. The machine learning model used in this paper is the classical three-layer feedforward neural networks, and the scaled conjugate gradient algorithm is adopted. Pearson correlation analysis method is used to find the relationships between course grade and the student eigenvalues. Findings Days of access has the highest correlation with course grade, followed by hits count, and connection time is less relevant to students’ course grade. Student age and gender have the lowest correlation with course grade. Binary classification models have much higher prediction accuracy than multi-class classification models. Data normalization and data discretization can effectively improve the prediction accuracy of machine learning models, such as ANN model in this paper. Originality/value This paper may help teachers to find some clue to identify students with learning difficulties in advance and give timely help through the online learning behavior data. It shows that acceptable prediction models based on machine learning can be built using a small and limited data set. However, introducing external data into machine learning models to improve its prediction accuracy is still a valuable and hard issue.

Sign in / Sign up

Export Citation Format

Share Document