scholarly journals The Effect of Propeller Scaling Methodology on the Performance Prediction

2018 ◽  
Author(s):  
Stephan Helma ◽  
Heinrich Streckwall ◽  
Jan Richter
Keyword(s):  
Open Water ◽  
Single Step ◽  
Complex Nature ◽  
Power Prediction ◽  
Water Characteristics ◽  
Scaling Procedure ◽  
Interaction Factors ◽  
Inherent Problem ◽  
Derivatives Of

In common model testing practise, the measured values of the self propulsion test are split into the characteristics of the hull, the propeller and into the interaction factors. These coefficients are scaled separately to the respective full scale values and subsequently reassembled to give the power prediction. The accuracy of this power prediction depends {\em inter alia} on the accuracy of the measured values and the scaling procedure. An inherent problem of this approach is, that it is virtually impossible to verify each single step, because of the complex nature of the underlying problem. In recent years the scaling of the open-water characteristics of propeller model tests attracted a renewed interest, fuelled by competitive tests, which became the norm due to requests of the customer. This paper will show the influence of different scaling procedures on the predicted power. The prediction is compared to the measured trials data and the quality of the prediction will be judged. The procedures examined are the standard ITTC~1978 procedure plus derivatives of it: the Meyne, the strip method and the βᵢ-method.

scholarly journals Micro-Hydropower in Nepal: Analysing the Project Process to Understand Drivers that Strengthen and Weaken Sustainability

2021 ◽  
Vol 13 (3) ◽  
pp. 1582
Author(s):  
Joe Butchers ◽  
Sam Williamson ◽  
Julian Booker
Keyword(s):  
Poor Quality ◽  
Hydropower Plant ◽  
Complex Nature ◽  
Sustainable Operation ◽  
Energy Projects ◽  
Project Cycle ◽  
The Government ◽  
Hydropower Industry ◽  
Key Events

Evaluating the sustainable operation of community-owned and community-operated renewable energy projects is complex. The development of a project often depends on the actions of diverse stakeholders, including the government, industry and communities. Throughout the project cycle, these interrelated actions impact the sustainability of the project. In this paper, the typical project cycle of a micro-hydropower plant in Nepal is used to demonstrate that key events throughout the project cycle affect a plant’s ability to operate sustainably. Through a critical analysis of the available literature, policy and project documentation and interviews with manufacturers, drivers that affect the sustainability of plants are found. Examples include weak specification of civil components during tendering, quality control issues during manufacture, poor quality of construction and trained operators leaving their position. Opportunities to minimise both the occurrence and the severity of threats to sustainability are identified. For the micro-hydropower industry in Nepal, recommendations are made for specific actions by the relevant stakeholders at appropriate moments in the project cycle. More broadly, the findings demonstrate that the complex nature of developing community energy projects requires a holistic consideration of the complete project process.

Understanding the changing nature of psychological contracts in 21st century organizations

2016 ◽  
Vol 7 (1) ◽  
pp. 4-35 ◽  
Author(s):  
Carlos-Maria Alcover ◽  
Ramón Rico ◽  
William H. Turnley ◽  
Mark C. Bolino
Keyword(s):  
Social Exchange ◽  
21St Century ◽  
Psychological Contract ◽  
Social Exchange Theory ◽  
Psychological Contracts ◽  
Complex Nature ◽  
Organizational Life ◽  
Exchange Relationships ◽  
Justice Perceptions

In recent years, scholars have increasingly recognized that the theoretical underpinnings of employee-organization relationships (EOR) are in need of further extension in light of recent organizational changes. In prior research, the study of EOR has been based on social exchange theory, and the psychological contract (PC) has played a central role in understanding this crucial aspect of organizational life. The main objective of this paper is to provide an integration of the existing literature by adopting a multiple-foci exchange relationships approach. Specifically, we looked at identification; the quality of relationships and exchanges with the leader, coworkers, and other organizational agents; justice perceptions involving several organizational sources; and perceived organizational, leader, and coworker support to expand our understanding of the PC. Overall, we advocate a multiple-foci exchange relationships approach that will ultimately enable us to develop a more comprehensive understanding of the complex nature of PCs in 21st century organizations.

Analysis of Inventory Management in Reverse Supply Chain Using Stochastic Dynamic Programming Model

2008 ◽  
Author(s):  
Badr O. Johar ◽  
Surendra M. Gupta
Keyword(s):  
Dynamic Programming ◽  
Inventory Management ◽  
Reverse Logistics ◽  
Stochastic Dynamic Programming ◽  
Public Awareness ◽  
Financial Burden ◽  
Probabilistic Approach ◽  
Complex Nature ◽  
Stochastic Dynamic

Reverse logistics is a critical topic that has captured the attention of government, private entities and researchers in recent years. This increase in the concern was driven by current set of government regulations, increase of public awareness, and the attractive economic opportunities. Also, environmentalists have always demanded Original Equipment Manufacturers (OEMs) to be more involved and be responsible of their products at the end of its life cycle. However, the uncertainty in quality of items returned, and its quantity discourage OEMs from participating in such programs. Because of the unique problems associated and the complex nature of the reverse logistics activities, numerous studies have been carried out in this field. One of those crucial areas is inventory management of End-of-Life (EOL) products. The take back program could possibly bring financial burden to OEM if it is not managed well. Thus, an efficient yet cost effective system should be implemented to appropriately manage the overwhelming number of returns. Previously, we have analyzed the problem based on the assumption that the number of core products returned and disassembled parts and subassemblies are known in advance. In this paper, we introduce a probabilistic approach where different quality levels of for every component disassembled are considered and different probabilities of these qualities given the quality of the returned product. The model utilizes a multi-period stochastic dynamic programming in a disassembly line context to solve the problem, and generate the best option that will maximize the system total profit. A numerical example is given to illustrate the approach. Finally, directions for future research are suggested.

“Isn’t There Any Other Way than Calling the Cops?”: How Differences in Initiation of Police Intervention Influence Survivor Safety

2021 ◽  
pp. 088626052110642
Author(s):  
Nkiru Nnawulezi ◽  
Jasmine Engleton ◽  
Selima Jumarali ◽  
Samantha Royson ◽  
Christopher Murphy
Keyword(s):  
Black Women ◽  
Partner Violence ◽  
Intervention Program ◽  
Risk Level ◽  
Complex Nature ◽  
Police Intervention ◽  
Alternative Interventions ◽  
Violence Intervention ◽  
Study Results

As formal crisis responders, police are trained in de-escalation tactics that are expected to mitigate intimate partner violence and promote survivor safety. However, the alignment between expected and actual practice of police intervention varies, especially when the survivor does not initiate the call, police treat the survivor poorly, or provide an undesirable arrest outcome. At best, unsuccessful interventions do not change survivors’ risk level, and at worse, elevate their risk of experiencing harm. The purpose of this qualitative study was to explore survivors’ perspectives on the process of police intervention, specifically how variations in initiation, quality of engagement, and arrest influence survivors’ safety. Twenty-four women whose partners were in a relationship violence intervention program were recruited to participate in the study. Results showed that many survivors described a range of ongoing, strategic violence perpetrated by their partners that required intervention; yet the complex nature of the violence often extended beyond police capacity. Either survivors called the police, or they were initiated externally by neighbors or strangers; some survivors had dual initiations. Whether survivors reported that police used safety practices during the intervention was related to who initiated the police. Arrests of abusive partners were inconsistent, and they varied based on number of previous calls to the police and visible signs of injury. Survivors of color, specifically Black women, self-initiated at higher rates, experienced fewer safety strategies used by police, and had fewer arrests. No matter the outcomes of police intervention, survivors actively engaged in strategies outside of formal systems to protect themselves and their families. Study results imply that police intervention may be ill-suited to support survivors’ safety goals and highlight a need for alternative interventions focused on de-escalation and prevention.

scholarly journals ANALISIS KUALITAS PERAIRAN BERDASARKAN KOMPOSISI DAN KELIMPAHAN FITOPLANKTON DI SUNGAI LANANGAN, KLATEN

2018 ◽  
Vol 7 (3) ◽  
pp. 253-262
Author(s):  
Faudzi Ath Tho Azzam ◽  
Niniek Widyorini ◽  
Bambang Sulardiono
Keyword(s):  
Sampling Method ◽  
Phytoplankton Community ◽  
Diversity Index ◽  
Animal Husbandry ◽  
Open Water ◽  
Survey Method ◽  
Purposive Sampling ◽  
Freshwater Aquaculture ◽  
Range Of Values

Sungai Lanangan merupakan bagian hulu Sungai Bengawan Solo yang terletak di Desa Daleman, Kecamatan Tulung, Kabupaten Klaten. Jenis limbah seperti limbah domestik, industri, pertanian, perikanan dan peternakan telah mencemari Sungai Lanangan. Limbah organik dari industri tepung aren dan mie soun yang dibuang di Sungai Lanangan mencapai 50 ton limbah per hari. Hal tersebut menyebabkan perubahan kualitas air dan komposisi fitoplankton di Sungai Lanangan.Penelitian ini dilakukan dari bulan Januari - Februari 2018 di Sungai Lanangan. Tujuan dari penelitian ini adalah untuk mengetahui kelimpahan dan komposisifitoplankton serta mengetahui kualitas perairan berdasarkan struktur komunitas fitoplankton di Sungai Lanangan tersebut. Penelitian ini menggunakan metode survei denganpengambilan sampel menggunakan metode purposive sampling. Frekuensi pengambilan sampel dilakukan setiap 1 minggu sekali selama 3 minggu. Sampel diambil dari 3 stasiun, dimana stasiun 1 dengan karakteristik perairan terbuka; Stasiun 2 dengan karakteristik dekat industri pengolahan tepung aren; dan stasiun 3 dengan karakteristik dekat dengan daerah budidaya air tawar.Hasil penelitian didapatkan 11 genera fitoplankton yaitu dari kelas Bacillariophyceae (4 genera), Cyanophyceae (2 genera), Chrysophyceae (1 genus), Ulvophyceae (2 genera), Zygnematophyceae (1 genus) dan Chlorophyceae (1 genus). Kelimpahan rata-rata fitoplankton tertinggi terdapat pada stasiun 2 dengan kelimpahan 1.989 ind/l yang didominasi oleh genus Oscillatoria. Indeks keanekaragaman rata-rata pada setiap stasiun adalah 1,68 pada stasiun 1; 1,63 pada stasiun 2; dan 1,52 pada stasiun 3. Dari hasil indeks keanekaragaman yang didapatkan tersebut menunjukkan kisaran nilai antara 1,52 hingga 1,68 yang berarti bahwa kualitas perairan Sungai Lanangan tercemar ringan.  Lanangan river is one upstream of Bengawan Solo river which located at Daleman, Tulung, Klaten. types of waste such as domestic waste, industrial waste, agriculture, fishery and animal husbandry polluted Lanangan river. Especially organic waste from palm starch and soun noodle industry that are dumped in the Lanangan river reaches 50 tonnes waste per day. This research was conducted from January to February 2018 in the Lanangan river. The purpose of this research is to find out the abundance and composition of phytoplankton; and to determine the water qualitybased on the structure of the phytoplankton community in Lanangan river. This research uses survey method and use purposive sampling method. The Frequency of sampling is done once a week for 3 week. The samples taken from 3 stations, where station 1 is open water; Station 2 is near palm starch and soun noodle industry; and station 3 is close to freshwater aquaculture area.The resultsof the research found 11 genus of phytoplankton in class Bacillariophyceae, Cyanophyceae, Chrysophyceae, Ulvophyceae, Zygnematophyceae and Chlorophyceae. The highest average of phytoplankton abundance found in station 2 with 1,989 ind/l which is dominated by the genus of Oscillatoria. The average diversity index each station is 1.68 at station 1; 1.63 at station 2; and 1.52 at station 3. From the results obtained the diversity index indicates the range of values between 1.52 to 1.68 which show that the water quality of Lanangan River is lightly to moderate polluted.  

scholarly journals QUALITY OF DECONSERVED BULL SPERM AFTER ADDITION OF MICROELEMENTS CONNECTED TO N-DERIVATIVE PEG400 TO DILUENT

2020 ◽  
Vol 21 (2) ◽  
pp. 230-237
Author(s):  
I. Yaremchuk ◽  
M. Sharan ◽  
D. Ostapiv ◽  
S. Kornjat ◽  
A. Korbecjkyj ◽  
...  
Keyword(s):  
Respiratory Activity ◽  
Polymer Composition ◽  
Equilibration Time ◽  
Nitrogen Vapor ◽  
Activity Of Enzymes ◽  
Oxidative Processes ◽  
Sperm Survival ◽  
Fertilization Capacity ◽  
Derivatives Of

The aim of the work was to establish optimal regimes for sperm cryopreservation when using nano-complexes in environments. The effect of micronutrients (Сu2+, Zn2+, Mn2+) in the polymer- transporters on the survival and fertilization capacity of sperm bulls was investigated. To assess the validity of the complexes N-derivative PEG400, ejaculates were chosen with volume – from 2 to 5 ml, concentration - 0,7 - 1,2×109 cells/ml and sperm activity 7.0 - 8.0 points. Sperm diluted with lactose-yolk-glycerin diluent was divided into parts: control - without addition and experimental with the addition of N-derivative PEG400 (N-PEG400) with a content of 1 ml of solution: Zn2+ - 0,0319 mmol; Cu2+ - 0.0222 mmol; Mn2+ – 0.0359 mmol. In the test sperm samples were added 0.01 ml of solutions of microelements in the polymer composition in ml of diluted ejaculate. Sperm survival was determined in sperm survival samples, motility, respiratory activity, activity of enzymes-markers of sperm fertility - succinate dehydrogenase (SDG) and cytochrome oxidase (CHO). It was found that the optimal equilibration time of sperm in the presence of microelements in the diluent of N-derivatives of PEG400 is 2.5 hours. In this case, the activity of sperm in the presence of N-derivatives of PEG400 depends on the exposure of spermatozoa over nitrogen vapor and the ability of trace elements to affect metabolic processes in sperm. The highest values of the values of the dynamic parameters of sperm characterized deconserved sperm with the addition to the dilution medium of Zn2+ and Mn2+ N-derivatives of PEG400 and exposure to nitrogen vapors for 8-10 minutes. It was found that Zn2+ and Mn2+ N-derivatives of PEG400 that were added in the diluent after cooled for 8-10 min over nitrogen vapor are characterized by high spermatozoa survival. The results of enzymes-markers activity show that the use of spermatozoa containing PEG400 Zn2+ or Mn2+ N-derivatives after 8-10 min exposure to nitrogen vapor, will ensure fertilization of 65% or more heifers and cows after the first insemination. Studied dose (0.01 ml of 0.0222 mmol solution / ml of diluted semen) of Cu2+ N-PEG400 should not be used in the diluent, when freezing the ejaculate of bulls, as the intensity of oxidative processes was elevated, which was manifested by a decrease in physiological characteristics of germ cells.

Understanding Smart City Solutions in Turkish Cities From the Perspective of Sustainability

2018 ◽  
pp. 236-266
Author(s):  
H. Filiz Alkan Meshur
Keyword(s):  
Information And Communication Technologies ◽  
Smart City ◽  
Social Life ◽  
Communication Technologies ◽  
Global Scale ◽  
Single Step ◽  
Information And Communication ◽  
General Practices ◽  
Urban Problems

The purpose of this chapter is to analyze the concept of smart city and its potential solutions to correct urban problems. Smart city practices and solutions have been investigated through the lens of a sustainable perspective. As the general practices in the global scale were examined, particular focus has been directed to smart city practices in Turkey and applicable suggestions have been developed. A number of cities in Turkey rank the lowest in the list of livable cities index. Consequential to the rapidly rising population ratios, the quality of provided services declines; economic and social life in cities are adversely affected and brand images of cities are deteriorated. With the implementation of smart city practices, such problems could be corrected, and these cities could gain competitive advantage over their rivals. The key component of this smart administration is to most effectively utilize information and communication technologies during each single step of this process.

scholarly journals Modelling and thermal simulation of absorber-free quasi-simultaneous laser welding of transparent plastics

2020 ◽  
Vol 64 (11) ◽  
pp. 1939-1946
Author(s):  
Nam-Phong Nguyen ◽  
Stefan Behrens ◽  
Maximilian Brosda ◽  
Alexander Olowinsky ◽  
Arnold Gillner
Keyword(s):  
Laser Wavelength ◽  
Single Step ◽  
Fibre Laser ◽  
Biotechnological Applications ◽  
Laser Transmission Welding ◽  
Emit Radiation ◽  
Radiation Sources ◽  
Plastics Processing ◽  
Plastic Components

Abstract The growing demands on the quality of plastic components and the trend towards miniaturisation are posing a great challenge on plastics processing technology. As many complex components can no longer be manufactured in a single step, joining processes such as laser transmission welding are gaining in importance. In classic laser transmission welding, the joining partners have different optical properties. The upper joining partner is transparent in the laser wavelength range, whilst the lower partner is absorbent due to the addition of absorber materials. In medical and biotechnological applications, the addition of absorber materials is often undesirable due to strict biocompatibility requirements. If, on the other hand, radiation sources are used which emit radiation in the area of the natural absorption of the plastic (λ = 1600–2000 nm), untreated transparent plastics can also be welded. In this work, a theoretical model will be presented to calculate the temperature distribution and progression during quasi-simultaneous welding using a thulium fibre laser (λ = 1940 nm). A sensitivity analysis is carried out to investigate the influence of different parameters on the heat affected zone (HAZ). The simulated HAZ is then compared with the HAZ from the experimental work.

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