Application of the Nozzle Analogy to Easily Predict Steam Turbine Performance With Minimal Geometric Input

2019 ◽  
Author(s):  
W. F. Fuls ◽  
J. S. Clark ◽  
A. C. Marx
Keyword(s):  
Correction Method ◽  
Specific Model ◽  
Steam Turbines ◽  
Nozzle Throat ◽  
Simple Method ◽  
Reaction Ratio ◽  
Low Load ◽  
Loss Coefficients ◽  
Cfd Analyses

Abstract A simple method for modelling steam turbines using a nozzle analogy was recently published. The method describes both stator and rotor components of a turbine with an appropriate nozzle definition, and makes use of the traditional velocity triangles to determine work output. What makes the method convenient is that it only requires a reasonable estimate of the effective nozzle throat area per blade row, as well as properly chosen loss coefficients. A complete turbine train with multiple stages can easily be solved using a simple 1-D pressure correction method. The method was demonstrated to match detailed inter-stage turbine data quite accurately. This paper elaborates on the application of the method. It presents a more thorough procedure for establishing the nozzle throat areas using a turbine lay-out drawing, as well as consideration of possible reaction ratio variation between successive stages. Furthermore, the loss coefficients are determined using the methods described by Traupel and Zehner. The paper presents these in a compressed and digitized format for easy implementation in a software code. A case study is presented to show how the model can quantify improvements to blade profiles. Another case study models a complete boiler feed pump turbine connected to the feedwater pumps and includes the partial arc governing stage and cold re-heat supply. This specific model demonstrated the method’s ability to accurately model a turbine at low load and high back pressure conditions. Turbine system modelers can apply the method presented here to their own equipment and obtain trustworthy results without the need for detailed profile geometry or complex CFD analyses. The method is however limited to subsonic flow between blade rows, hence some modern transonic last stage blade designs might not be adequately represented.

The Tradition of Religious Books (Kitabs) Printing: Case Study of the Production and Reproduction of Religious Books (Kitabs) in Cianjur and Sukabumi, West Java, Indonesia

2020 ◽  
Vol 17 (2) ◽  
pp. 291-320
Author(s):  
Asep Saefullah
Keyword(s):  
Data Collection ◽  
Screen Printing ◽  
The Other ◽  
West Java ◽  
Simple Method ◽  
Original Essays ◽  
Printed Books ◽  
Religious Books ◽  
Living Tradition

Tulisan ini membahas fenomena penyebaran kitab-kitab cetak keaga­maan di Jawa Barat, khususnya di Sukabumi dan Cianjur. Jenis kitab ini biasanya menggunakan tulisan Arab dengan bahasa Sunda dan menggu­nakan aksara Pegon. Kitab-kitab cetak dari jenis-jenis itu diproduksi dan direproduksi, dan masih digunakan sampai hari ini. Oleh karena itu, fenomena ini dapat disebut sebagai “living tradition”. Pengumpulan data dilakukan dengan melacak dan merekam kitab-kitab yang diproduksi (disalin atau dikarang) dan direproduksi (dicetak atau digandakan) dengan metode seder­hana, yakni fotocopi dan pencetakan tradisional seperti stensil, sablon, dan "cetak toko". Tulisan ini bertujuan untuk memetakan dan merevisi kategorisasi kitab-kitab tersebut dari kajian terdahulu berdasarkan jenis karya, seperti karangan asli, tuqilan, terjemahan, syarḥ (penjelasan), khulasah (ringkasan) yang lain, dan juga berdasarkan bahasa dan aksara yang digunakan. Selain itu, tulisan ini juga mengamati lembaga-lembaga atau individu-individu yang masih mereproduksi buku-buku (kitab-kitab) keagamaan sederhana seperti perusahaan percetakan atau pesantren yang menerbitkan kitab-kitab tersebut. Pada akhir artikel ini, ada beberapa saran dalam upaya untuk melestarikan kitab-kitab cetak dan karya-karya tersebut.Kata kunci: kitab, jenis karya, pencetakan tradisional, Sunda, Pegon, Jawa Barat This paper discusses the phenomenon of the spreading of religious printed books (kitabs) in West Java, especially in Sukabumi and Cianjur, which are characterized by the use of Arabic writing in Sundanese (or known as Pegon script). The printed books (Kitabs) of those types are produced and reproduced, and are still used to this day. Therefore, this phenomenon can be called as a “living tradition”. Data collection was conducted by tracing and recording religious books (kitabs) that are pro-duced (rewritten or compossed) and reproduced (printed or duplicated) with a simple method, known as photocopying and traditional printing such as stencils, screen printing, and “shop printing”. This paper aims to map and revise the categorization of these Kitabs from previous studies based on the types of works including original essays, tuqilan (quotations), translation, sharh (explanation), khulaṣah (summary), or the other, and also based on the language and the script used. In addition, this paper also observes the institutions or individuals that are still reproducing these printed religious books such as the printing company or pesantren that publish such kitabs. At the end of this article, there are some suggestions in attempts to preserve those printed kitabs and the works.Keywords: Kitabs, type of work, traditional printing, Sunda, Pegon, West Java

scholarly journals Assessing an Atmospheric Correction Algorithm for Time Series of Satellite-Based Water-Leaving Reflectance Using Match-Up Sites in Australian Coastal Waters

2021 ◽  
Vol 13 (10) ◽  
pp. 1927
Author(s):  
Fuqin Li ◽  
David Jupp ◽  
Thomas Schroeder ◽  
Stephen Sagar ◽  
Joshua Sixsmith ◽  
...  
Keyword(s):  
Coastal Waters ◽  
Atmospheric Correction ◽  
Correction Method ◽  
In Situ Measurements ◽  
Landsat 8 ◽  
Correction Algorithm ◽  
Simple Method ◽  
North East ◽  
The Impact

An atmospheric correction algorithm for medium-resolution satellite data over general water surfaces (open/coastal, estuarine and inland waters) has been assessed in Australian coastal waters. In situ measurements at four match-up sites were used with 21 Landsat 8 images acquired between 2014 and 2017. Three aerosol sources (AERONET, MODIS ocean aerosol and climatology) were used to test the impact of the selection of aerosol optical depth (AOD) and Ångström coefficient on the retrieved accuracy. The initial results showed that the satellite-derived water-leaving reflectance can have good agreement with the in situ measurements, provided that the sun glint is handled effectively. Although the AERONET aerosol data performed best, the contemporary satellite-derived aerosol information from MODIS or an aerosol climatology could also be as effective, and should be assessed with further in situ measurements. Two sun glint correction strategies were assessed for their ability to remove the glint bias. The most successful one used the average of two shortwave infrared (SWIR) bands to represent sun glint and subtracted it from each band. Using this sun glint correction method, the mean all-band error of the retrieved water-leaving reflectance at the Lucinda Jetty Coastal Observatory (LJCO) in north east Australia was close to 4% and unbiased over 14 acquisitions. A persistent bias in the other strategy was likely due to the sky radiance being non-uniform for the selected images. In regard to future options for an operational sun glint correction, the simple method may be sufficient for clear skies until a physically based method has been established.

Identification and prioritization of farmers' innovations in northern Ghana

2014 ◽  
Vol 30 (6) ◽  
pp. 537-549 ◽  
Author(s):  
Justice A. Tambo ◽  
Tobias Wünscher
Keyword(s):  
Smallholder Farmers ◽  
Household Survey ◽  
Northern Ghana ◽  
Plant Residues ◽  
Simple Method ◽  
Pests And Diseases ◽  
Innovation Contest ◽  
Scientific Validation ◽  
Livestock Diseases

AbstractFarmers are innovators and experimenters and not just adopters of introduced technologies. The innovations developed by farmers could complement the highly promoted externally driven technologies in addressing the numerous challenges facing agriculture. The aim of this paper was to identify outstanding innovations developed by smallholder farmers in northern Ghana, and prioritize the high potential ones for further scientific validation or dissemination. Using an innovation contest that rewards farmers' creativity, we identified 29 promising innovations. Additionally, 19 innovations were scouted through a household survey. The innovations are largely extensive modifications of existing practices or combinations of different known practices in unique ways to save costs or to address crop and livestock production constraints. While some of the identified innovations can be recommended or disseminated to other farmers, most of them may require further validation or research. However, validating all of these innovations will be very expensive and time-consuming. We propose the multi-criteria decision-making analysis (MCDM) as a simple method to prioritize farmers' innovations. Using this method, we find that among the most promising innovations are those involving the control of weeds, pests and diseases using plant residues and extracts, and the treatment of livestock diseases using ethnoveterinary medicines. We briefly explain the six most highly ranked innovations. This case study from northern Ghana provides further proof that smallholder farmers develop diverse and spectacular innovations to address the myriad challenges they face, and these need to be recognized and promoted. We also conclude that contest and MCDM are useful methods that can be applied in unearthing and prioritizing farmer innovations, respectively.

Design of Fazl-Tash novel method for sustainable resilient comprehensive supplier selection problem

Kybernetes ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hamed Fazlollahtabar ◽  
Navid Kazemitash
Keyword(s):  
Supplier Selection ◽  
Huge Number ◽  
Simple Method ◽  
Content Type ◽  
Novel Method ◽  
Rank And Select ◽  
The Cost ◽  
Supplier Selection Problem ◽  
Industrial Company

Purpose However, due to the huge number of studies and on the other hand to be new and creative, the represented models and methods – as the two main parts of this field – have been got more complicated, which consequently have been turned into unpractical research studies for the realistic situations. Therefore, the purpose of this study is the representation of a novel and simple method to deal with the aforementioned gap. Design/methodology/approach To this end, Fazl-Tash method have been proposed, in which a thorough and complete model including 114 criteria and a simple technique to rank and select the best supplier have been presented. Sustainability and resiliency are considered in collecting criteria effective on supplier selection. Findings The method was carried out in a case study in an industrial company. The efficiency of the proposed method is evaluated in comparison with other conventional approaches. Originality/value As selecting the supplier plays a crucial role to bring some important advantages for companies, such as coping with the cost and time problems and influencing the majority of contemporary markets’ requirements, in recent years, there have been representing more effective studies in the supplier selection literature.

scholarly journals Bias correction capabilities of quantile mapping methods for rainfall and temperature variables

2020 ◽  
Author(s):  
Maedeh Enayati ◽  
Omid Bozorg-Haddad ◽  
Javad Bazrafshan ◽  
Somayeh Hejabi ◽  
Xuefeng Chu
Keyword(s):  
River Basin ◽  
Bias Correction ◽  
Correction Method ◽  
Quantile Mapping ◽  
Topographic Features ◽  
Temperature Variable ◽  
Transformation Functions ◽  
Karkheh River Basin ◽  
The Karkheh River

Abstract This study aims to conduct a thorough investigation to compare the abilities of QM techniques as a bias correction method for the raw outputs from GCM/RCM combinations. The Karkheh River basin in Iran was selected as a case study, due to its diverse topographic features, to test the performances of the bias correction methods under different conditions. The outputs of two GCM/RCM combinations (ICHEC and NOAA-ESM) were acquired from the CORDEX dataset for this study. The results indicated that the performances of the QMs varied, depending on the transformation functions, parameter sets, and topographic conditions. In some cases, the QMs' adjustments even made the GCM/RCM combinations' raw outputs worse. The result of this study suggested that apart from DIST, PTF:scale, and SSPLIN, the rest of the considered QM methods can provide relatively improved results for both rainfall and temperature variables. It should be noted that, according to the results obtained from the diverse topographic conditions of the sub-basins, the empirical quantiles (QUANT) and robust empirical quantiles (RQUANT) methods proved to be excellent options to correct the bias of rainfall data, while all bias correction methods, with the notable exceptions of performed PTF:scale and SSPLIN, performed relatively well for the temperature variable.

Application of GE Low Load Package on an Existing District Heating Power Plant: A Case Study

2020 ◽  
Author(s):  
Antonio Mambro ◽  
Francesco Congiu ◽  
Francesco Piraccini
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
District Heating ◽  
Low Pressure ◽  
Heating Power ◽  
Low Pressure Turbine ◽  
Low Load ◽  
Flow Through ◽  
Last Stage

Abstract The continuous increase of variable renewable energy and fuel cost requires steam turbine power plants to operate with high flexibility. Furthermore, the reduction in electricity price is forcing many existing and new district heating power plants to further optimize the heat production to maintain a sustainable business. This situation leads to low pressure steam turbines running at very low volume flow for an extended time. In this work, a case study of an existing 30 MWel district heating power plant located in Europe is presented. The customer request was the removal of the steam turbine last two stages along with the condenser to maximize steam delivery for district heating operations. However, based on the experience gained by GE on low load during the last years, the same heat production has been guaranteed without any significant impact on the existing unit, excluding any major modification of the plant layout such as last stage blading and condenser removal. Making use of the latest low flow modeling, the minimum cooling flow through the low-pressure turbine has been reduced by more than 90% compared to the existing unit. Optimization of the hood spray system and logic will reduce trailing edge erosion during low load operation leading to a significant extension in the last stage blade lifetime. These modifications, commercialized by GE as the Advanced Low Load Package (ALLP), provide a cheap, flexible and effective solution for the customer. With today’s knowledge, GE has the capability to guarantee low load operation minimizing the mass flow through the low-pressure turbine to the minimum required for safe operation. As a benefit to the customer, this option allows a gain in operational income of about 1.5 M€ per year.

scholarly journals A COLREGs-Based Dynamic Navigation Safety Domain for Unmanned Surface Vehicles: A Case Study of Dolphin-I

2020 ◽  
Vol 8 (4) ◽  
pp. 264
Author(s):  
Jian Zhou ◽  
Chenxu Wang ◽  
Anmin Zhang
Keyword(s):  
Collision Avoidance ◽  
Domain Boundary ◽  
Specific Model ◽  
Unmanned Surface Vehicles ◽  
Intelligent Machines ◽  
Dynamic Navigation ◽  
International Regulations ◽  
Domain Models ◽  
Navigation Safety

Unmanned Surface Vehicles (USVs) are intelligent machines that have been widely studied in recent years. The safety of USVs’ activities is a priority issue in their applications; one effective method is to delimit an exclusive safety domain around the USV. Besides considering collision avoidance, the safety domain should satisfy the requirements of encounter situations in the COLREGs (International Regulations for Preventing Collisions at Sea) as well. Whereas the model providing the safety domain for the USVs is defined through the experience of the manned ships, a specific model for USVs has been rarely studied. A dynamic navigation safety domain (DNSD) for USVs was proposed in this paper. To construct the model, the essential factors that could affect the navigation safety of the USVs were extracted via a rough set, and the extension functions of these factors were carried out. The DNSD was employed in various situations and compared with the ship domain models of common ships. It was found that the domain boundary can be automatically corrected according to the change in the working conditions when the DNSD is in use. Compared with the Fujii and Coldwell models, the DNSD can provide a larger safety area for a USV’s action of collision avoidance.

Human resources ranking in a cloud-based knowledge sharing framework using the quality control criteria

Kybernetes ◽  
2017 ◽  
Vol 46 (5) ◽  
pp. 876-892 ◽  
Author(s):  
Parisa Fouladi ◽  
Nima Jafari Navimipour
Keyword(s):  
Quality Control ◽  
Human Resources ◽  
Hierarchical Structure ◽  
Simple Method ◽  
Content Type ◽  
Quality Control Criteria ◽  
Control Criteria ◽  
Selection Of

Purpose This paper aims to propose a new method for evaluating the quality and prioritizing of the human resources (HRs) based on trust, reputation, agility, expertise and cost criteria in the expert cloud. To evaluate some quality control (QC) factors, a model based on the SERVQUAL is used. Design/methodology/approach The aim of this paper is to offer a fast and simple method for selecting the HRs by the customers. To achieve this goal, the ranking diagram of different HRs based on the different criteria of QC is provided. By means of this method, the customer can rapidly decide on the selection of the required HRs. By using the proposed method, the scores for various criteria are evaluated. These criteria are used in the ranking of each HR which is obtained based on the evaluation conducted by previous customers and their colleagues. First, customers were asked to select their needed criteria and then by constructing a hierarchical structure, the ranking diagram of different HRs is achieved. Using a ranking system based on evaluating the quality of the model, satisfy the customer needs to be based on the properties of HRs. Also, an analytical hierarchical process-based ranking mechanism is proposed to solve the problem of assigning weights to features for considering the interdependence between them to rank the HRs in the expert cloud. Findings The obtained results showed the applicability of the radar graph using a case study and also numerically obtained results showed that a hierarchical structure increases the quality and speed rating of HR ranking than the previous works. Originality/value The suggested ranking method in this paper allows the optimal selection due to the special needs of any given customer in the expert cloud.

scholarly journals A patient-specific model of total knee arthroplasty to estimate patellar strain: A case study

2016 ◽  
Vol 32 ◽  
pp. 212-219 ◽  
Author(s):  
Adeliya Latypova ◽  
Arash Arami ◽  
Fabio Becce ◽  
Brigitte Jolles-Haeberli ◽  
Kamiar Aminian ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Specific Model ◽  
Patient Specific ◽  
Total Knee
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