Instrumentation Selection and Uncertainty Analysis for Performance Test of Small Centrifugal Compressors

2004 ◽  
Author(s):  
Amro M. Al-Qutub ◽  
Fahad A. Al-Sulaiman
Keyword(s):  
Uncertainty Analysis ◽  
Performance Test ◽  
Correct Selection ◽  
Small Scale ◽  
Performance Parameters ◽  
Centrifugal Compressors ◽  
Accuracy Of Results ◽  
Lower Uncertainty ◽  
Selection Of

In the design phase of centrifugal compressors, it is essential to have some experimental results on performance. The extent of usefulness of the experiments depends on quality and accuracy of the results. Part of proper experimental procedure is the correct selection of instrumentation leading to lower uncertainty in the final results. ASME PTC 10 (Performance Test Code on Compressors and Exhausters) requires fluctuation limits on the measured performance parameters. This does not guarantee limits for accuracy of performance parameters. Also, different experimental setup will affect uncertainty of the results, even with similar instrumentation accuracy. The present research deals with uncertainty analysis for performance evaluation of small-scale centrifugal compressor. The instrumentation errors are accommodated in the relation to ASME PTC 19.1 (test uncertainty). The analysis takes into consideration the correlated bias limits. Selection of proper type of instruments for measuring associated parameters is based on literature review. A case study is included as an example to illustrate the selection on instrumentation accuracy and preferred bias correlations. The analysis is a useful tool in designing experiments for testing compressor and optimizing accuracy of results.

scholarly journals Procedure for the Selection of Rubber Compound in Rubber-Metal Springs for Vibration Isolation

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1737
Author(s):  
Milan Banić ◽  
Dušan Stamenković ◽  
Aleksandar Miltenović ◽  
Dragan Jovanović ◽  
Milan Tica
Keyword(s):  
Numerical Simulation ◽  
Constitutive Model ◽  
Vibration Isolation ◽  
Correct Selection ◽  
Virtual Experiment ◽  
Rubber Compound ◽  
Key Factor ◽  
Railway Engineering ◽  
Selection Of

The selection of a rubber compound has a determining influence on the final characteristics of rubber-metal springs. Therefore, the correct selection of a rubber compound is a key factor for development of rubber-metal vibration isolation springs with required characteristics. The procedure for the selection of the rubber compound for vibration isolation of rubber-metal springs has been proposed, so that the rubber-metal elements have the necessary characteristics, especially in terms of deflection. The procedure is based on numerical simulation of spring deflection with Bergström-Boyce constitutive model in virtual experiment, with a goal to determine which parameters of the constitutive model will lead to spring required deflection. The procedure was verified by case study defined to select rubber compound for a rubber–metal spring used in railway engineering.

Studies regarding correct selection of statistical methods for the needs of increasing the efficiency of identification of land for consolidation—A case study in Poland

2019 ◽  
Vol 87 ◽  
pp. 104064 ◽  
Author(s):  
Justyna Wójcik-Leń ◽  
Przemysław Leń ◽  
Monika Mika ◽  
Hubert Kryszk ◽  
Paweł Kotlarz
Keyword(s):  
Statistical Methods ◽  
Correct Selection ◽  
Selection Of

scholarly journals Peak Power of Heat Source for Domestic Hot Water Preparation (DHW) for Residential Estate in Poland as a Representative Case Study for the Climate of Central Europe

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8047
Author(s):  
Łukasz Amanowicz
Keyword(s):  
Heat Source ◽  
Peak Power ◽  
Residential Buildings ◽  
Renewable Energy Sources ◽  
Hot Water ◽  
Correct Selection ◽  
Domestic Hot Water ◽  
Heat Demand ◽  
Selection Of

Due to the energy transformation in buildings, the proportions of energy consumption for heating, ventilation and domestic hot water preparation (DHW) have changed. The latter component can now play a significant role, not only in the context of the annual heat demand, but also in the context of selecting the peak power of the heat source. In this paper, the comparison of chosen methods for its calculation is presented. The results show that for contemporary residential buildings, the peak power for DHW preparation can achieve the same or higher value as the peak power for heating and ventilation. For this reason, nowadays the correct selection of the peak power of a heat source for DHW purposes becomes more important, especially if it uses renewable energy sources, because it affects its size and so the investment cost and economic efficiency. It is also indicated that in modern buildings, mainly accumulative systems with hot water storage tanks should be taken into account because they are less sensitive to design errors (wrongly selected peak value in the context of the uncertainty of hot water consumption) and because they result in acceptable value of peak power for DHW in comparison to heating and ventilation.

scholarly journals The Choice of Language for Note-taking for the Purposes of Consecutive Interpreting

2021 ◽  
Vol 27 (4(54)) ◽  
pp. 51-61
Author(s):  
Dariusz Hanusiak
Keyword(s):  
Mother Tongue ◽  
Target Language ◽  
Small Scale ◽  
Note Taking ◽  
First Semester ◽  
Case Study Analysis ◽  
Natural Choice ◽  
Consecutive Interpreting ◽  
Selection Of

The subject of the article is the choice of language that is used for notetaking for consecutive interpreting. The paper is based on a small-scale empirical case study analysis of note-taking by interpreting students. The analysis was aimed at determining which language – source language (SL) or target language (TL) – was preferred by students, who were given freedom of choice regarding the selection of language that they would use for the preparation of notes to help with consecutive interpreting tasks. The study group consisted of three cohorts of translation and interpreting students who were at the end of their first semester of work with consecutive. The students were asked to prepare notes for a regular consecutive task, from English into Polish; Polish was the mother tongue for all of the students. The outcomes of the analysis may show what might be the “natural” choice of language for notation and may provide suggestions about improving the system of teaching notation in the case of novice interpreters.

Help wanted

2017 ◽  
Vol 31 (2) ◽  
pp. 122-131 ◽  
Author(s):  
Jacqueline Brodie ◽  
Sebastiaan Huib Van Saane ◽  
Renata Osowska
Keyword(s):  
Added Value ◽  
Small Scale ◽  
Exploratory Research ◽  
Mentor Relationship ◽  
Start Up ◽  
Mentoring Support ◽  
Embedded Case Study ◽  
Depth Interviews ◽  
Selection Of

The purpose of the research presented in this article was to investigate the added value of mentoring for entrepreneurs during the start-up phase. This small-scale exploratory research focused on five start-up entrepreneurs in Scotland to determine the entrepreneurs’ perceptions regarding the ‘added’ value of their mentoring support. To achieve the research aim, a qualitative approach was adopted and an embedded case study strategy was followed with data collection from semi-structured in-depth interviews. The case study findings indicated a selection of perceived benefits of the mentoring experience for the start-up entrepreneurs, which included gaining business knowledge, getting guidance and prioritizing goals, an increase in confidence and access to relevant networks. The results point towards the use of multiple mentors and peer support at start-up to maximize the full benefits of the mentoring process. The study also provides tentative recommendations for supporting agencies as well as entrepreneurs to enhance the value in the mentee–mentor relationship.

An Advanced Optimization Procedure for the Thermodynamic Selection of Centrifugal Compressors Stages

2008 ◽  
Author(s):  
Simone Pazzi ◽  
Marco Giachi ◽  
Ashraf Al Musleh ◽  
Massimo Pusceddu ◽  
Nidal Ghizawi
Keyword(s):  
Objective Function ◽  
Performance Optimization ◽  
Optimization Algorithms ◽  
Optimization Procedure ◽  
Optimization Process ◽  
Performance Parameters ◽  
Centrifugal Compressors ◽  
Operating Range ◽  
Size Constraints ◽  
Selection Of

The present paper deals with the application of optimization algorithms to the selection of centrifugal stages for industrial compressors. The optimization procedure has been developed allowing an automatic stage selection to meet a mathematically stated target including the most relevant performance parameters and machine operating and size constraints. The thermodynamic selection is assessed by means of an internal-use CCS (Centrifugal Compressors Selector) that computes compressor flange-to-flange performance with a given sequence of stages. The CCS has been coupled to an internally used optimization code (“PEZ”, Perl Version of Easy Optimizer) using the CCS as the performance evaluator. The user indicates which flange variables must be matched as well as the stages parameters that the optimizer is allowed to alter, with their respective ranges of acceptable variation. The optimization objective reflects the job specifications and can be stated as a combination of several performance parameters. Constraints are enforced through appropriate penalty terms added to the objective function. The performance optimization process includes an automatic rotordynamic analysis that checks the rotor mechanical acceptability. The optimization of two different in-line barrel compressors, originally configured manually, brought a remarkable 2% flange-to-flange performance increase and a 5% gain in operating range respectively. Each case required about 10 hours windows desktop workstation.

Uncertainty analysis at large scales: limitations and subjectivity of current practices - a water quality case study

2007 ◽  
Vol 56 (6) ◽  
pp. 1-9 ◽  
Author(s):  
R.M. Bijlsma ◽  
P. Groenendijk ◽  
M.W. Blind ◽  
A.Y. Hoekstra
Keyword(s):  
Uncertainty Analysis ◽  
Large Scale ◽  
Evidence Base ◽  
Uncertainty Assessment ◽  
Scale Model ◽  
Small Scale ◽  
Model Studies ◽  
Large Scale Model ◽  
Current Practices

Uncertainty analysis for large-scale model studies is a challenging activity that requires a different approach to uncertainty analysis at a smaller scale. However, in river basin studies, the practice of uncertainty analysis at a large scale is mostly derived from practice at a small scale. The limitations and inherent subjectivity of some current practices and assumptions are identified, based on the results of a quantitative uncertainty analysis exploring the effects of input data and parameter uncertainty on surface water nutrient concentration. We show that: (i) although the results from small- scale sensitivity analysis are often applied at larger scales, this is not always valid; (ii) the current restriction of the uncertainty assessment to uncertainty types with a strong evidence base gives structurally conservative estimates; (iii) uncertainty due to bias is usually not assessed, but it may easily outweigh the effects of variability; (iv) the uncertainty bandwidth may increase for higher aggregation levels, although the opposite is the standard assumption.

scholarly journals Evaluation of roadside service centers. Case study: Zahedan to Khash Road

2017 ◽  
Vol 7 (4) ◽  
pp. 374-381
Author(s):  
Maryam Karimiyan Bostani ◽  
Fateme Hashemzehi ◽  
Mahmood Reza Anvari
Keyword(s):  
Correct Selection ◽  
Transportation Industry ◽  
Related Factors ◽  
Job Opportunities ◽  
Selection Systems ◽  
Research Findings ◽  
The City ◽  
Selection Of

In the recent century, the excessive and unplanned growth of urbanism and inattention to the proper and correct selection of locations for roadside uses, especially roadside services, have led to the appearance of problems such as lack of spaces for service centers, inappropriate access, and other problems. The strategic location of the city of Zahedan among other cities of Sistan and Baluchistan Province and its connection to the national corridors requires development and growth of transportation industry and improvement of its performance. Some of the utmost important centers that have to be established for this purpose on the roadsides in the required quantities are roadside service and welfare centers. Therefore, in order to maintain and promote the security of the roads in the country, the establishment of such centers requires studies, evaluations and eventually, determination of appropriate and secure locations. In this study, considering the necessity of establishing service and welfare centers on the Zahedan to Khash Road, first, the existing centers were evaluated from the perspectives of passengers, then, by the use of site selection systems, some locations were determined in the high traffic parts of this road. The research methodology in this study is descriptive-analytical which is used in order to analyze the collected data. The research findings show that according to the passengers, the conditions of roadside services on the Zahedan to Khash Road and the existing infrastructures are weak. However, they are satisfied with social and security-related factors. The passengers also stated that these roadside service centers have created job opportunities in the region. They also have been effective in providing security of the roads.

scholarly journals Decision support system based in AHP method to selection vendors of clinical laboratorys inputs

2019 ◽  
Vol 10 (5) ◽  
pp. 1536
Author(s):  
André Andrade Longaray ◽  
Anderson Picua Gonçalves ◽  
Vilmar Gonçalves Tondolo ◽  
Rosana Tondolo ◽  
Catia Maria dos Santos Machado
Keyword(s):  
Selection Process ◽  
Clinical Analysis ◽  
Correct Selection ◽  
Analytic Hierarchy ◽  
Organizational Goals ◽  
Analysis Laboratory ◽  
Hierarchy Process ◽  
The City ◽  
Selection Of

In a competitive marketing scenario, the purchasing area contributes significantly to the achievement of organizational goals. Its mission is to identify the competitive needs of products and services, becoming responsible for the timely delivery, costs optimization and quality. Within shopping, a correct selection of vendors is important for this to happen. From this perspective, the present study aims to develop a model that assists in the vendors’ selection process. This way, a case study was carried out in a clinical analysis laboratory located in the city of Rio Grande, where the AHP (Analytic Hierarchy Process) was used as an intervention tool. The development process consisted in three stages. The first one aimed at structuring the model, in which the hierarchy of criteria was defined. In the second step, the judgments were carried out and the relative weights for each criterion and subcriterion were calculated. Finally, the third step aimed at applying the model developed in a purchasing process. The model was tested in a selection process that involved the evaluation of three vendors of a laboratorial input, in order to identify which one met the demands of the organization. The result obtained with its use was considered satisfactory, this way, the model was approved by the manager who participated in the structuring process of the AHP hierarchy.

Topik-Topik Komunikasi Dakwah Dalam Mesej Akidah Kepada Masyarakat Orang Asli di Selangor

Sains Insani ◽  
2018 ◽  
Vol 3 (2) ◽  
pp. 15-21
Author(s):  
Zulkefli Aini ◽  
Abdul Ghafar Don ◽  
Ahmad Irdha Mokhtar ◽  
Nur Uswah Ahmad Fauzi
Keyword(s):  
Qualitative Study ◽  
Study Design ◽  
Verbal Feedback ◽  
Structured Interviews ◽  
Orang Asli ◽  
Case Study Design ◽  
Beliefs And Practice ◽  
Islamic Faith ◽  
Selection Of

One of the factors that can affect a person's behavior is a communication message. In the context of the da`wah, preachers who involved actively in da`wah communication with the Orang Asli should be able to ensure that the message conveyed can be understood by the target group. In addition, the selection of the correct messages of da`wah based on the foremost priority simplify the process of sharing information between the preachers and the Orang Asli. Accordingly, this article aims to identify specific topics of Islamic faith (akidah) submitted by the Orang Asli in the process of da`wah communication and to identify verbal feedback given by the preachers to the Orang Asli of the topics. This qualitative study using case study design and data was collected through semi-structured interviews. Interviews involving nine preachers were active in da`wah activity to the Orang Asli community in Selangor. Data were analyzed thematically according to the specified objectives. The study found that the topics frequently raised by the Orang Asli is concerned about belief in Allah, belief in Malaikat, and belief in Qada' and Qadar. The topics may be found within the framework of worldview in their beliefs and practice of ancient traditions. Therefore, the preachers gave verbal feedback on these topics is based on a clear and precise sample corresponding to the level of their thinking. The emphasis on these topics is very important to strengthen and purify the faith of the community.Keywords: Communication; Message; Preacher; Indigenous community Abstrak: Elemen mesej dalam komunikasi merupakan salah satu faktor yang dapat memberi kesan terhadap perubahan tingkah laku seseorang. Dalam konteks dakwah, pendakwah yang terlibat dalam proses komunikasi dakwah dengan Orang Asli seharusnya berkebolehan memastikan kandungan mesej yang disampaikan boleh difahami oleh sasaran dakwahnya. Di samping itu, pemilihan mesej dakwah yang betul mengikut keutamaan memudahkan proses perkongsian maklumat antara pendakwah dengan Orang Asli. Sehubungan dengan itu, artikel ini bertujuan untuk mengenalpasti topik-topik tertentu dalam mesej akidah yang dikemukakan oleh masyarakat Orang Asli kepada pendakwah dan mengenalpasti maklum balas lisan yang diberikan oleh pendakwah kepada Orang Asli terhadap topik tersebut. Kajian kualitatif ini menggunakan reka bentuk kajian kes dengan pengumpulan data melalui temu bual separa struktur. Temu bual melibatkan sembilan orang pendakwah yang aktif dalam aktiviti dakwah masyarakat Orang Asli di Selangor. Data kajian dianalisis secara tematik mengikut objektif yang ditentukan. Kajian ini mendapati bahawa topik-topik yang sering dikemukan oleh Orang Asli kepada pendakwah dalam penyampaian mesej akidah ialah berkenaan tentang keimanan kepada Allah SWT, keimanan kepada malaikat, dan keimanan kepada qada’ dan qadar. Topik-topik berkenaan didapati berada dalam kerangka worldview kepercayaan dan amalan tradisi mereka. Sehubungan dengan itu, pendakwah memberikan maklum balas lisan terhadap topik-topik tersebut adalah berdasarkan keterangan yang jelas dan contoh yang tepat bersesuaian dengan tahap pemikiran mereka. Penekanan terhadap topik-topik tersebut merupakan perkara yang penting dalam rangka mengukuhkan dan memurnikan akidah masyarakat Orang Asli.Kata kunci: Komunikasi; Mesej; Pendakwah; Komuniti Orang Asli

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