bluuebunny/crossref_metadata_2025 huggingface dataset:
سبل الإفادة من تطبيقات الحوسبة السحابية في تقديم خدمات المعلومات
بدولة الإمارات العربية المتحدة
Authors: Al-Ulaymi Tharwat
Published: April 2017

أدى التطور المتسارع في تكنولوجيا الشبكات إلى اتجاه العديد من المؤسسات إلي إتاحة تطبيقاتها للاستخدام من خلال شبكة الانترنت فيما يعرف باسم الحوسبة السحابية (Computing Cloud )، حيث أتاحت هذه التقنية لمستخدميها مميزات أفضل مثل توفير النفقات أو إتاحة خدمات لقطاع اكبر من المستفيدين وهناك إدراك متزايد بأنه سيأتي يوم وتكون الحوسبة السحابية الأداة الخامسة بعد الماء والكهرباء والغاز والاتصالات الهاتفية هذه الأداة الحاسوبية، مثل كل المرافق الأربعة الأخرى القائمة سوف توفر مستوى أساسي من خدمات الحوسبة التي تعتبر ضرورية لتلبية الاحتياجات اليومية للمجتمع عامة.

ولقد أظهرت قطاعات مثل الحكومة الإلكترونية، والأعمال المصرفية الإلكترونية والرعاية الصحية الإلكترونية و المكتبات الرقمية ازدهاراً كبيراً في مناطق من العالم حيث البنية التحتية قابلة لتقديم الدعم لها، ومن منظور إقليمي، فإن الإمارات تقود الطريق في هذه المجالات من خلال إنشاء بيئة مواتية للمنافسة، وبنى تحتية متقدمة ومن ثم تناولت هذه الدراسة مفهوم الحوسبة السحابية والميزات و العيوب المتعلقة بها والخدمات و التطبيقات التي أتاحتها في تقديم خدمات معلوماتية بدولة الإمارات العربية المتحدة مع دراسة إمكانية الاستفادة منها في بيئة المكتبات ومن ثم الخروج بتصور لبناء ائتلاف شبكي معتمد على الحوسبة السحابية.
دراسة تحليلية لواقع الإفصاح الطوعي عن المعلومات في المصارف العراقية
ومدى تأثره بتطبيق آليات الحوكمة
من قبل
Authors: Aldabbagh Lukman MA , Ibrahem Laith K
Published: April 2017

في ضوء عولمة الأسواق المالية والتطورات التقنية والمعلوماتية التي يشهدها العالم أصبح الإفصاح الإلزامي لا يلبي الاحتياجات المتعددة لمستخدمي التقارير والمعلومات المحاسبية وظهرت الحاجة الى الإفصاح الطوعي لتخفيض التباين في المعلومات بين المدراء و المستثمرين ولتحسين نوعية المعلومات المفصح عنها , وكما هو معروف ان حوكمة الشركات خصوصا في القطاع المصرفي قد ساهم في تعزيز الشفافية والإفصاح والحد من ممارسات المحاسبة الإبداعية وتقليص فجوة المعلومات بين الإدارة وأصحاب المصالح, لهذا يهدف البحث الى دراسة اثر آليات الحوكمة على الإفصاح الطوعي في المصارف المدرجة في سوق العراق للأوراق المالية, ومن اهم النتائج التي توصلت إليها الدراسة هو وجود علاقة ارتباط معنوية بين الآليات الداخلية للحوكمة والإفصاح الطوعي بالإضافة الى وجود اثر ذات دلالة معنوية لإلية مجلس الإدارة على مستوى الإفصاح الطوعي للمصارف عينة الدراسة .
Feasibility of converting existing residential buildings to net zero-energy buildings in Egypt
Authors: Albadry Somaya
Published: April 2017

Green architecture, sustainable buildings, environmental friendly, and other terms have recently become popular in the construction field among professionals and non-professionals. Although they are mostly needed and highly feasible, the application of these ideas is not yet at the same level of popularity in Egypt. Researchers are trying to fill this gap by providing different types of recommendations, methodologies, and guidelines to be followed. The aim of this study is to propose a method for solving the energy problem in the building sector in Egypt. Since it is concerned with the existing building stock, the proposed method will address retrofitting strategies, not new design strategies. The study suggests the nZEB (net zero-energy buildings) method as a possible solution for the problem and provides a guideline to be used among the rest of the existing building types. The study uses energy simulation to validate its initial assumptions and test the feasibility of the proposed guideline. The final outcome of the study is a method that combines both retrofitting and renewable energy strategies that will suit the Egyptian context, and has the potential to convert existing buildings to nZEB buildings. The study starts with the analysis of the current situation of both the existing buildings and the energy sector in Egypt. First, it reviews the classification of the existing building types in the Egyptian context, analyzing the energy consumption patterns and the inefficiencies leading to these patterns. Then, it defines the nZEB concept to familiarize the reader with its different aspects. The empirical part of the study uses several cases for a number of prototypes of residential building types in Egypt. Finally, the proposed guideline is applied to an actual existing building and its feasibility is tested by simulation. The study concludes by suggesting a potential energy saving by applying nZEB strategies to existing residential buildings in Egypt. Future research on different building types is required to validate the nZEB method across different building types.
Does allelopathy increase invasiveness of Prosopis juliflora (sw.) Dc in arid land environment?
Authors: Abu-Dieyeh Mohammed H.
Published: April 2017

Prosopis juliflora is highly recognized for its invasive character and its detrimental effects on different plant species across the world due to possessing allelochemicals. Our field observations indicated high prevalence of new recruitments of P. juliflora than other native associated plants in the study site. The purpose of this study is to assess the allelopathic effects of aqueous extracts of P. juliflora on selected Qatari flora. 100 g L− 1 of powdered of plant leaves was used to prepare the stock extract and then diluted to reach the following concentration: 2 mg ml− 1, 4 mg ml− 1, 6 mg ml− 1 and 8 mg ml− 1 from stock were prepared. Acacia tortilis, Prosopis cineraria, Sueda aegyptica, and Halopeplis perfoliata, were negatively impacted by aqueous extract at different treatment levels. The results showed that although seed germinations of Acacia tortilis was not significantly affected by the extract, however a significant reduction was observed in radical lengths starting from a concentration as low as 2 mg ml− 1. While low significant reduction (10%) was exerted on seed germination of Prosopis cineraria at higher concentrations of 6 mg ml− 1 and 8 mg ml− 1, the seed radical length was significantly reduced starting at the lowest concentration (2 mgml− 1). The seed germination and seed radical length of Sueda aegyptica were reduced by almost 2-folds at the lowest concentration treatment (2 mg ml− 1). Seed germination of Halopeplis perfoliata was also reduced significantly at concentration of 4 mg ml− 1. Seedlings growth of Aeluropus lagopoides, Caroxylon imbricatum and Tetraena qatarensis were also evaluated after being subjected to P. juliflora extract. Although no significant differences in plant height of Aeluropus lagopoides occurred due to treatments, significant reduction in dry matter biomass were found at concentrations of 6 mg ml− 1 and 8 mg ml− 1 of extract compared to control plants. The seedling growth and dry biomass of Caroxylon imbricatum were significantly declined at higher concentration of 8 mg ml− 1. However, the seedling growth and dry biomass of Tetraena qatarensis were significantly reduced at all treatment levels. Autotoxic effects of P. juliflora were also observed at concentrations of 6 mg ml− 1 and 8 mg ml− 1. Based on the research carried out, P. juliflora is invasive and utilize allelopathy as one major tool of its invasiveness. The species has detrimental effects on the Qatari native flora, and it is important to protect them from the growing spread of this invasive species.
Responses of terrestrial ecosystems under climate change manipulation: Effects of open field experimental warming and precipitation manipulation on ecophysiological characteristics of plants
Authors: Son Yowhan , Chang Hanna
Published: April 2017

It is expected that air temperature will increase and the pattern of precipitation will change. In Qatar, mean annual temperature and rainfall during winter have increased for the past 40 years. Changes in temperature and precipitation might influence ecosystem function such as productivity and nutrient cycling. Numerous climate change manipulation studies have examined the effect of climate change on ecosystem function. There are various methods for warming and precipitation manipulation; temperature can be increased by using greenhouse, open top chamber, infrared lamp and heating cable, and precipitation can be artificially manipulated by using panels to block out rain and water irrigation. However, there is a very limited number of experimental manipulation studies in arid regions compared to other ecosystems. We conducted three experimental warming and precipitation manipulation studies in Korea by using infrared lamp, transparent panel and irrigation system. Seed germination rate of Pinus densiflora and Abies holophylla increased by the warming treatment, and root collar diameter and height of 5 tree species seedlings out of 8 target tree species increased by the warming treatment. Also, the warming treatment extended the growing season by advanced leaf unfolding and delayed leaf senescence of P. densiflora and Quercus variabilis seedlings. Photosynthetic responses were species-specific to the warming treatment and net photosynthetic rate of P. densiflora seedlings decreased by the warming treatment with decreased precipitation. Based on our study, it appeared that the ecophysiological responses of seedlings to climate change manipulation varied by species. Further studies are needed to investigate the effects of multiple environmental factors including CO2 on ecophysiological characteristics of plants to climate change. In addition, long-term monitoring and modeling approaches should be simultaneously applied to understand regional climate change impact.
Improving technology one molecule at the time
Authors: Nielsen Ole John
Published: April 2017

An example and the history of improving technology one molecule at the time will be presented. Halogenated organic compounds play an important role in atmospheric and environmental chemistry. There has recently been an extensive review of the atmospheric chemistry of halogenated organic compounds. The most current understanding of sources, emissions, atmospheric concentrations and environmental sinks and fates will be presented. The chemistry associated with formation and loss of stratospheric ozone and processes related to halogenated organics is described and the contribution of halogenated organics to radiative forcing of climate change is discussed in context of the environmental impact of halogenated organic compounds.
Winter thermoregulation of free-ranging Ethiopian hedgehogs (Paraechinus aethiopicus) in Qatar
Authors: Yamaguchi Nobuyuki
Published: April 2017

Biologists focus on thermoregulation of desert mammals in terms of how they minimise heat gain during hotter months, and put less effort on how they maximise heat gain during cooler months. Heat gain may contribute to energy savings of desert mammals during cooler period when the ambient temperature in desert is substantially lower than their body temperatures. We investigated the thermoregulation in free-ranging Ethiopian hedgehogs, Paraechinus aethiopicus, during winter using radio-telemetry in Qatar. Temperatures detected by the tag attached to hedgehogs were significantly higher than ambient temperatures throughout the day, and the difference was more extreme during the mid-day. We also observed several hedgehogs basking with their radio-tags exposed to direct sunlight. It is possible that basking is beneficial for the hedgehog's winter thermoregulation in the desert where plenty of solar radiation is available.
تقييم واقع المكتبات الأكاديمية في جامعة السلطان قابوس في ضوء المعيار العربي الموحد للمكتبات الجامعية
Authors: بنت حمدان العامري جميلة , الريامي رباب بنت جمعه
Published: April 2017

يعد تحقيق جودة الأداء على جميع مستويات مختلف الأنشطة والخدمات التي تتيحها المكتبات الجامعية ضرورة حتمية في إطار سعي المكتبات للحصول على الاعتماد الأكاديمي الذي يمنحها مكانة مرموقة بين نظيراتها و زيادة قدرتها التنافسية، حيث تهدف الدراسة الحالية إلى تقييم واقع المكتبات الاكاديمية في جامعة السلطان قابوس في ضوء المعيار العربي الموحد للمكتبات الجامعية، وكذلك التعرف على مدى ملائمة أبنية ومساحات المكتبة، وأنظمة الإجراءات الادارية والخدمات العامة والفنية ، مع محاولة إبراز مواطن القوة والضعف في أداء المكتبات الاكاديمية في الجامعة. وطبقت الدراسة المنهج الوصفي النوعي واستخدمت المقابلة الشخصية مع مدراء المكتبات عينة الدراسة (المكتبة الرئيسية، المكتبة الطبية، مركز المعلومات بكلية الاقتصاد والعلوم السياسية، مكتبة كلية الآداب والعلوم الاجتماعية)، وكذلك طبقت أسلوب الملاحظة لقائمة مراجعة تم تصميمها بناءً على عناصر المعيار العربي الموحد.

وتوصلت الدراسة إلى مجموعة من النتائج أهمها: إن للمكتبات عينة الدراسة مباني مستقلة للاستخدام الحصري والانشطة الاخرى المتعلقة بها، أن المكتبة الرئيسية لها سياسة واضحة لكل خدمة تقدمها، فهي تعتبر المزود الرئيسي والمكتبة الحاضنة لجميع المكتبات داخل الجامعة في اشتراكاتها والعمليات الفنية ما عدا المكتبة الطبية فهي تشترك معها في اشتراكاتها للمصادر الالكترونية، أما في العمليات الفنية فهي مستقلة بذاتها. كذلك فإن جميع المكتبات عينة الدراسة توافقت مع بنود المعيار فيما يتعلق بعملية الاستبعاد من حيث السياسة وعناصرها الزمنية والموضوعية. وأيضًا أن قسم المراجع في المكتبة الرئيسية يقدم خدماته بشكل فعّال وباستخدام كل الطرق التي تم الإشارة إليها في المعيار ويتفوق على ما جاء ذكره في بنود المعيار المتعلقة بالخدمة المرجعية، أما مكتبتي مركز المعلومات بكلية الاقتصاد والعلوم السياسية والمكتبة الطبية فإنها تقتصر على الطريقة المباشرة (بزيارة المستفيد للمكتبة ومقابلة موظفي الخدمة المرجعية) وغير مباشرة (البريد الإلكتروني، الهاتف، الفاكس). وكذلك تلاءمت جميع المكتبات عينة الدراسة مع ما جاء به المعيار فيما يتعلق بوضع سياسة وشروط مرتبطة بخدمة الإعارة توضح نوعيات وعدد الإعارات، مدة الإعارة، فئات الإعارة لكل فئة من المصادر ولكل فئة من المستفيدين.

وبناء على النتائج فإن الدراسة توصي بعمل عمادة علمية مختصة للمكتبات، بحيث توحد الإجراءات الفنية والعامة وتسهل عملية التبادل، وتفعيل دور تطبيق المعايير العربية والأجنبية في المكتبات الأكاديمية لتيسير التعامل مع المكتبات الأخرى. وأيضًا كاقتراح للمعيار نفسه إنه لابد أن تستحدث المعيار في مجال الخدمات الالكترونية، لأن في الوقت الحالي في عصر الثورة التكنولوجية وتقنية المعلومات استحدثت الكثير من الخدمات والتي تقدمها المكتبات سواء فيمل يتعلق بالخدمة المرجعية (Ask librarian، RSS) وكذلك الأسئلة الشائعة، شبكات التواصل الاجتماعي وغيرها، بالإضافة للمستجدات فيما تتعلق بتقديم خدمة الإعارة والارجاع والتجديد على الموقع.
Short communication: Response of rainbow trout (Oncorhynchus mykiss) to mirror images
Authors: Rauw Wendy M. , García-Cortés Luis A. , Villarroel Morris , Gomez-Raya Luis
Published: April 2017

The response of cultured rainbow trout to their mirrored image was investigated. Thirty fish were placed individually in two novel aquariums consecutively for 10 min each. Walls in one aquarium were covered with mirrors on all four sides, whereas the walls of the other aquarium were non-transparent black. Because all four walls were covered with mirrors, the mirrored image of the fish was reproduced multiple times such that ‘a group’ of fish was created surrounding the individual. Half of the fish started in the aquarium with the mirrors, whereas the other half started in the mirrorless aquarium. Fish swim faster in the aquarium with mirrors than in the mirrorless aquarium (2.95 vs. 2.40 cm/s; p < 0.01), indicating a positive behavioural response towards their mirrored images. Fish did not show aggressive interactions towards their mirrored images. Being confronted with ‘a group’ of fish and not just one ‘opponent’ may have inhibited aggressive behavior, or individuals may not have considered the images to be fellow individuals. Fish that swam faster in the mirrorless aquarium also did so in the aquarium with mirrors (r = 0.73; p < 0.0001), indicating a persistent behavioural coping response (boldness) in response to the two novel environments. Mirrors may be used to influence social behaviour of fish in aquaculture; further research is needed to investigate the influence of mirror placement in tanks of group housed trout on growth and behaviour.
Discounting in agro-industrial complex. A methodological proposal for risk premium
Authors: Marques-Perez Inmaculada , Guaita-Pradas Inmaculada , Pérez-Salas José-Luis
Published: April 2017

The estimation of the discount rate is decisive for a reliable economic valuation. The discount rate has to be adjusted for the risks related to the company, the sector which the company has its market, and the risks related to the investment project. We present a proposal to incorporate the risk premium to the discount rate. The novelty of the methodology is that difference risk groups according to activity as a factor to adjust the cost of capital to companies. The study applies the methodology to the Agro-Industrial Complex (AIC) in Spain. The AIC is formed by industries that add value to farming production. This sector’s economic success demands financial management techniques that assess risk. The conventional method responds neither to the heterogeneity of the economic activities that make up the AIC, nor to differentiating risk by groups. The proposed methodology distinguishes activity groups in accordance with the NACE (National Code of Economic Activities) and uses net profitability variability to distinguish the risk in each group. Our results demonstrate the various levels of risk per group. The results show that among all the groups that form the AIC there are wide differences between levels of risk; thus, the risk neutral groups present risk levels on the order of 150 times lower than the groups extreme risk levels.
Evaluation of the design effects of different agropastoral systems on the diversity and density of spiders
Authors: Almada Melina S. , González Alda , Corronca José A.
Published: April 2017

Sustainable agro-ecological design is challenging when the goal is self-regulation of the system. The objective of this study was to evaluate if the agropastoral design system affects the spider community, as spiders are the main predators in these production systems, and to determine those designs which maximize the diversity and density of spiders. The study was conducted during 2009/2010, at the Experimental Research Station of Agriculture (EEA-INTA) Reconquista (Santa Fe, Argentina) where we considered four different designs: C1 (five agricultural fields), C2 (three agricultural fields and four livestock fields), C3 (six agricultural fields and one livestock field) and C4 (five agricultural fields and one forest area). In each design, the spiders were collected by pitfall traps and suction samples with a G-Vac (garden-vacuum). The designs proposed were considered on the basis of environmental heterogeneity. The C4 treatment had the greatest number of species, followed by C2, C3 and C1 (183, 178, 144 and 142 species, respectively), and C2 presented the greatest abundance of spiders followed by C4, C3 and C1 (n=5708, 4785, 4271 and 3448, respectively). Eight guilds were present in C3 and C4. This study is the first to evaluate the diversity of spiders in agropastoral systems in Argentina. Our results show that designs that include more fields with livestock or equal to those for agriculture, as well as forest areas, increase environmental heterogeneity. Therefore, the presence of a biological controller and dominant predatory group will be possible with sustainable designs that have environmental heterogeneity, contributing to improved pest control in agricultural systems.
Influence of plum rootstocks on agronomic performance, leaf mineral nutrition and fruit quality of ‘Catherina’ peach cultivar in heavy-calcareous soil conditions
Authors: Mestre Lucía , Reig Gemma , Betrán Jesús A. , Moreno María-Ángeles
Published: April 2017

The agronomic performance and leaf mineral nutrition of the non-melting clingstone peach cv. ‘Catherina’ was evaluated on seven hexaploid plum rootstocks, as well as one Prunus persica seedling. They were assessed over a period of 15 years in a field trial at the Experimental Station of Aula Dei-CSIC (Zaragoza, Spain), located in the Ebro Valley (NE Spain). Growing conditions generated varying levels of tree mortality, the highest with Constantí 1, Monpol and Montizo, whereas all Adesoto, GF 655/2 and PM 105 AD trees survived well. GF 655/2 and P. Soto 67 AD proved to be the most dwarfing rootstocks, while Constantí 1 and Monpol were the most invigorating and generated greater cumulative yields. However, the highest yield efficiency was recorded on GF 655/2 and Montizo, although they did not differ significantly from Adesoto and P. Soto 67 AD. The highest average values for fruit weight were observed on PM 105 AD and the lowest on GF 655/2, but they did not differ significantly from the rest of the rootstocks. The highest average values for the soluble solids content was observed on the Pollizo rootstocks Adesoto and PM 105 AD, followed by P. Soto 67 AD. All rootstocks induced N deficiency, with the exception of Constantí 1, GF 655/2 and Montizo, and iron deficiency, except PM 105 AD. The invigorating rootstock Constantí 1 seems to induce higher SPAD values. According to the ΣDOP index, Montizo presented the most suitable balanced nutritional index, but it did not differ significantly from the rest of the rootstocks except GF 655/2 and P. Soto 67 AD.
De toegankelijkheid van het tuchtrecht in de gezondheidszorg
Authors: Rube A.
Published: April 2017

De toegankelijkheid van het tuchtrecht in de gezondheidszorg

In deze bijdrage staat het medisch tuchtrecht centraal. In december 2016 heeft de minister van Volksgezondheid, Welzijn en Sport een wetsvoorstel bij de Tweede Kamer aanhangig gemaakt, dat de toegankelijkheid en effectiviteit van het wettelijk tuchtrecht in de gezondheidszorg moet verbeteren. De centrale vraag van deze bijdrage is in hoeverre deze doelen met het wetsvoorstel worden bereikt. Het primaire doel van medisch tuchtrecht is het bevorderen en bewaken van de kwaliteit van de beroepsuitoefening. Het is tevens een middel om te bereiken dat personen die een medisch beroep uitoefenen en daardoor een bijzondere verantwoordelijkheid dragen, hun beroep uitoefenen op een wijze die met die verantwoordelijkheid overeenstemt. Het tuchtrecht dient daarmee een algemeen belang; het is niet gericht op persoonlijke genoegdoening van de klager. Hierdoor is toegankelijkheid van het tuchtrecht van essentieel belang. In het genoemde wetsvoorstel wordt een aantal voorstellen gedaan om dat te verbeteren, maar de auteur meent dat dat doel niet in alle gevallen wordt bereikt. Met name de invoering van griffierecht acht zij in dit licht problematisch. In plaats daarvan zou ondersteuning van de klager de voorkeur moeten krijgen en breder worden ingezet dan waar het wetsvoorstel nu in voorziet.
Population and energy elasticity of tornado casualties
Authors: Fricker Tyler , Elsner James B. , Jagger Thomas H.
Published: April 2017

Tornadoes are capable of catastrophic destruction and mass casualties, but there are yet no estimates of how sensitive the number of casualties are to changes in the number of people in harm's way or to changes in tornado energy. Here the relationship between tornado casualties (deaths and injuries), population, and energy dissipation is quantified using the economic concept of “elasticity.” Records of casualties from individual tornadoes over the period 2007–2015 are fit to a regression model. The coefficient on the population term (population elasticity) indicates that a doubling in population increases the casualty rate by 21% [(17, 24)%, 95% credible interval]. The coefficient on the energy term (energy elasticity) indicates that a doubling in energy dissipation leads to a 33% [(30, 35)%, 95% credible interval] increase in the casualty rate. The difference in elasticity values show that on average, changes in energy dissipation have been relatively more important in explaining tornado casualties than changes in population. Assuming no changes in warning effectiveness or mitigation efforts, these elasticity estimates can be used to project changes in casualties given the known population trends and possible trends in tornado activity.
The essential value of long‐term experimental data for hydrology and water management
Authors: Tetzlaff Doerthe , Carey Sean K. , McNamara James P. , Laudon Hjalmar , Soulsby Chris
Published: April 2017

Observations and data from long‐term experimental watersheds are the foundation of hydrology as a geoscience. They allow us to benchmark process understanding, observe trends and natural cycles, and are prerequisites for testing predictive models. Long‐term experimental watersheds also are places where new measurement technologies are developed. These studies offer a crucial evidence base for understanding and managing the provision of clean water supplies, predicting and mitigating the effects of floods, and protecting ecosystem services provided by rivers and wetlands. They also show how to manage land and water in an integrated, sustainable way that reduces environmental and economic costs.
Water and life from snow: A trillion dollar science question
Authors: Sturm Matthew , Goldstein Michael A. , Parr Charles
Published: April 2017

Snow provides essential resources/services in the form of water for human use, and climate regulation in the form of enhanced cooling of the Earth. In addition, it supports a thriving winter outdoor recreation industry. To date, the financial evaluation of the importance of snow is incomplete and hence the need for accelerated snow research is not as clear as it could be. With snow cover changing worldwide in several worrisome ways, there is pressing need to determine global, regional, and local rates of snow cover change, and to link these to financial analyses that allow for rational decision making, as risks related to those decisions involve trillions of dollars.
Shaft Vibration: Axial Vibration
Authors: Schiffer Wilfried
Published: April 2017

Torsional vibrations are dominant in shaft lines of diesel marine installations. Axial shaft vibrations are very rarely the cause of severe damage cases, but they generate dynamic forces acting on the ship hull. Four‐stroke marine installations are not of interest due to short stroke, but for two‐stroke diesel engine installations, axial vibration calculations with active and inactive axial dampers are required by some classification societies. This article explains the meaning of the torsional–axial coupling coefficients of the crankshaft for the axial vibrations. Calculated and measured axial amplitudes for an installation with active and inactive axial dampers are compared. The influence of the firing order on axial amplitudes is demonstrated.
Maneuvering in Shallow and Confined Water
Authors: Vantorre Marc , Eloot Katrien , Delefortrie Guillaume , Lataire Evert , Candries Maxim , Verwilligen Jeroen
Published: April 2017

The maneuvering characteristics are highly affected by the under‐keel clearance. In shallow water, the results of standard maneuvers reveal a decreased maneuverability and an increased straight‐line stability. This modified behavior is mainly to be ascribed to the modified flow around the hull, but also the control forces exerted by rudder and propeller are different compared to the deep‐water case. Besides the effect of vertical limitations, a ship navigating parallel to the horizontal boundaries of navigation areas will also experience the so‐called bank effects, that is, disturbing forces and moments due to the asymmetry of the flow around the hull.

In some harbors and their approach channels, the bottom is covered with a layer of fluid mud. This not only complicates bottom survey, but also affects a ship's propulsive performance and maneuvering due to the specific rheological properties of the mud layer and to the generation of internal waves in the interface between water and mud. Finally, different types of hydrodynamic interaction between ships may take place in restricted waters, due to encountering and overtaking maneuvers, the effect of passing ships on moored vessels, lightering operations, and ship–tug interactions.
Description of Ice Types and Ice Conditions
Authors: Frederking Robert
Published: April 2017

Ice forms in water bodies under the influence of climate, oceanography, and the geography of the surrounding land. It grows as a result of thermal processes and mechanical processes. First‐year level sea ice can grow thermally to a maximum thickness of about 2 and 2.5 m in extreme winters. Ice floes interacting with each other can build accumulations of broken ice, ridges, which can attain sail heights of 5 m and keel depths of 25 m, but are usually smaller. In some seas, the ice does not completely melt in summer and perennial accumulation of deformed multi‐year ice can reach thicknesses greater than 10 m. Large seasonal and interannular variations in ice are normal and superimposed on them are the effects of longer term climate changes. Different sea areas have varying combinations of these ice types throughout the year. The likely ice conditions encountered in various sea areas of interest for marine and offshore operations are described.
Navigation in Ice Conditions
Authors: Aro Ilmari
Published: April 2017

This article is to show what one should take in consideration when planning a voyage through ice covered sea area.
Ship Performance in Ice
Authors: Izumiyama Koh
Published: April 2017

Ship performance in ice is described. When a ship proceeds in ice, the hull breaks and deflects ice. Reaction forces to the breaking and deflecting ice generate resistance. Performance in level ice is the most fundamental measure for performance of ice‐going ships. Level ice performance of a ship is described by an “
h–V
curve,” which is determined by the relation between net thrust and resistance. Bow forms are designed to enhance bending failure of ice to minimize ice resistance. Resistance in brash ice arises from deflecting ice by the ship hull. Brash ice is modeled as a Mohr–Coulomb type material in a resistance formula. When a ship turns in ice, pivoting motion of the ship is hindered by the ice edge of broken channel. Bow reamers create a wider channel to enhance turning capability. The advent of azimuthal thrusters has largely improved ship maneuverability in ice. Results of field measurements show that energy consumed by a ship to sail through a ridge is in proportion to the cross‐sectional area of the ridge.
Ship Registration
Authors: Wright David
Published: April 2017

Ship Registration is the method of establishing the identity of a ship, its nationality, ownership, and compliance with internationally established standards of construction and operation. The legal criteria for these standards have evolved over time as ships and shipping commerce have evolved and generally as a result of lessons learned from shipping accidents. The standards are contained in International Conventions of the United Nations and its subsidiary body the International Maritime Organization. Ships that trade in international waters are required to be registered to a nation that is a member of the United Nations and has adopted the international shipping conventions into its national laws. The nation, or Flag State, is required to administer a register of the ships on its flag and establish the identity of each ship both physically and in the electro‐magnetic spectrum, the ship's owners, operational managers, and crew managers. It is also required to ensure its safety which includes its construction, equipment, and seaworthiness every aspect of its crew, including certification, training and qualifications and the correct operation of the ship. The Flag State must also ensure that the ship is properly equipped and surveyed while it is on the flag and must also investigate any accidents or mal‐operation. The International Conventions are the minimum standards that the Flag State can apply, and they are at liberty to require higher standards should it wish. There are benefits in operating a national shipping register and significant risks as well; it is also a crowded and competitive market and it should be noted that the many of the larger Flag States are small nations with relatively small populations, little industry and specialize in offering offshore services to multi‐national corporations. Such countries are known as Open Registers or Flags of Convenience. A key aspect of maintaining maritime safety and preventing environmental pollution from shipping is for Flag States to operate their shipping registers responsibly and identify the beneficial owners to ensure they are accountable for their ships.
Flag State Administrations
Authors: Bell Douglas
Published: April 2017

The duties of a flag state are set out in the United Nations Convention on the Law of the Sea 1982. It formalized what had been the best practice for many years. It also states that there must be a genuine link between the ship and its flag state, this requirement has caused controversy. The structure of a maritime administration varies greatly from state to state, depending on the size of its fleet, the resources available, and the general structure of its government. Some states contract the administration of maritime affairs to a private company. Open registers in the modern sense developed following the introduction of prohibition in the United States; Panama was persuaded to allow non‐Panamanian nationals to register ships under its flag and thus allowed US companies, which registered their ships in Panama, to sell alcohol on those ships. The concept developed from there, until over half of the world's fleet is now registered under an open register administration. Safety concerns about the development of open registers are contradicted by statistics that show a steady decline in ship losses and the number of oil spills over recent decades.
Detailed Structural Design
Authors: Lehmann Eike
Published: April 2017

This article deals with detailed structural design of the steel work of seagoing ships. Welding technology has the most important influence in the design of the structural design of the entire steel structure of seagoing ships. The dimensioning of the thickness of plates and the reinforcement with stiffeners, beams, and knees can be carried out with simple design formulas, based on the classical beam and plate theory and notified by the rules of the classification societies. This approach to the detailed structural design is still common practice today in order to create the initial structural design. The simple design formulas are also essential for preparing the numerical models for direct structural analyses with FEM for defining the final dimensions of the plate thicknesses, reinforcements, and so on. In this context, it is very important to know the principal functions of the local structural details, to provide an inside into the structural behavior and the strength and effectiveness of the structure.
Global Hull‐Girder Response (Quasi‐Static, Prismatic Beam Models)
Authors: Varsta Petri , Remes Heikki , Romanoff Jani
Published: April 2017

In the conceptual design phase of a ship, it is important to optimize the structural elements of the hull girder with respect to minimum weight. This enables maximization of the payload. This design task requires deep understanding of the hull‐girder response under operational loading including still water and wave loads. The quasi‐static response of a prismatic beam is preferred due to the shortage of time. The classical analysis exploits the bending and torsion theory presented within the field of solid mechanics. In addition, it is important to take into account the special features of the hull girder due to the structural topology of this dynamically loaded thin‐walled, lightweight structure.
Underwater Noise Radiation, Mechanisms, and Control
Authors: Grushetsky Igor V. , Kalyu Valeriy A. , Shlemov Yuri F. , Tarovik Vladimir I.
Published: April 2017

Essential aspects of underwater noise (UN) from ships are addressed. The importance of ship UN problems has been emphasized by the introduction of UN regulations embracing all types of ships. The physical models of ships used in the investigations of the UN‐generation processes and engineering estimations are described. Among the issues addressed are shipboard machinery treated as noise sources, paths of vibrational energy propagation from sources, and radiation into water; methods for measuring the UN from ships, including measurement accuracy estimates, as well as techniques for revealing the major UN sources. Key measures to be taken for meeting the ship UN requirements are presented.
Ship Noise Control
Authors: Fischer Raymond W. , Bahtiarian Michael A.
Published: April 2017

This article is intended to provide a basic understanding and overview of the critical factors controlling habitability noise onboard vessels. It is intended to assist the marine community—shipyards, naval architects, marine engineers, regulators, and owners—in addressing issues and important design parameters related to generation and control of shipboard noise. It includes a description of noise‐generating mechanism, specifics on noise sources in ships, information regarding noise transmission through the hull structure, an overview of methods used for noise analysis, and noise control during the design stage or during modernization. There is a discussion of inspection and compliance testing. With the proper understanding of how noise is generated, controlled, and measured, ships can be delivered to various noise criteria in a straightforward, economic, and optimal manner.
Ship Vibration, Global, and Local Modes
Authors: Mumm Holger
Published: April 2017

This article is intended to provide an overview of ship structural vibration and its effects on human comfort and structural integrity. It addresses natural and forced vibration phenomena as originating from the action of time‐variant impulsive and continuous vibration excitation forces on global and local hull structures. After an introduction into important terms, principles, and concepts in the field of ship vibration, the global and local vibration modes as excited by the major sources of ship vibration are addressed. This includes seaway‐induced whipping and springing vibration and structural oscillations forced by periodic vortex shedding and the different kinds of continuous vibration excitations originating from ship main engines and propellers. For an easier understanding of the excited natural vibration modes and operational deflection shapes, the underlying vibration excitation force mechanisms are briefly described as well. Focus is on ship vibrations as encountered in engineering practice. Guidance is provided, how ship vibration phenomena can be investigated during the ship's design phase and which vibration countermeasures can be expected to be effective.
Static and Dynamic Shaft System Alignment
Authors: Smith Andrew
Published: April 2017

This chapter deals with design of the low speed shaft line of marine installations, and what this design should aim to achieve, so as to contribute to reliable operation. The challenges of achieving satisfactory alignment varies from ship type to type and these are discussed. Numerical analyses that are undertaken to arrive at an acceptable design are examined , together with the issues that are required to be considered in these computations, such that the design constraints are achieved.

Alignment Procedures are reviewed to ensure that the shaft line and components are constructed and installed in a manner to achieve the design requirements.

Practical Aspects of installing the shaft line and components are discussed. Pros and cons of measurement techniques are explored suggesting how correlation of the installed system with the design conditions are achieved and recorded.
Measurements and Structural Monitoring
Authors: Storhaug Gaute
Published: April 2017

Model tests and hull monitoring can be used to measure wave‐induced hull girder loads, which are used to assess the risk of fatigue cracking and hull girder collapse. Although, the objective of model tests and hull monitoring may differ, they are valuable supplements to numerical analysis. More reliable and realistic results can be obtained, and physical aspects not covered by the idealized numerical codes can be included. Example of such is whipping and springing vibrations, which are difficult to incorporate in hydroelastic analysis. Hull monitoring is, however, not limited to hull girder loads and can include any sensor onboard covering any need.

Measurements of hull girder loading are often regarded as the “truth,” but there are several uncertainties. It can be stated that the numerical analysis can never be better than the measurements, which have been used in the validation; hence, efforts should be made to limit the uncertainties in the measurements.

Model tests and hull monitoring are not frequently used. Significant initial costs, lack of standardization, poor data quality, unawareness, and substandard suppliers contribute to this. The benefit during the operational life can by far exceed the costs related to model tests during the design phase or installation costs of the real vessel. Preplanned and proper data assessment is a prerequisite to bring value and decision support to the stakeholders.
Propeller Manufacture and Tolerances
Authors: Janssen André , Leever Sylvia
Published: April 2017

This article describes the manufacturing of ship screw propellers. A fixed pitch propeller (FPP) and different parts of a controllable pitch propeller (CPP) are made by casting and subsequent machining. The most commonly used material is NiAl‐bronze, although also stainless steel is used. Based upon a casting design, a sand mold is made and the liquid metal is poured into the mold. After solidification, the part is taken out of the mold and a visual check is made before the rough casting is measured. An intermediate balancing and dye penetrant investigation is made after pre‐grinding of the casting. If any casting defects are present and permitted to repair, these are repaired before final grinding and polishing. Grinding and machining techniques, including NC simulation, are described for the different parts of the propeller. The final product must meet the specified dimensions within the allowed tolerances. Depending on the purpose of the vessel, a different (tighter) tolerance class than ISO 484 may apply.
Inviscid Hydrodynamics
Authors: Manasseh Richard
Published: April 2017

The fundamentals of fluid dynamics are introduced in a context relevant to maritime engineering. The properties of fluids and definitions of features of fluid flows are given. The fundamental laws of fluid motion are explained, focusing on the laws of conservation of mass and momentum. An integral form of the momentum equation, Bernoulli's equation, is derived and its use is demonstrated. The concepts of vorticity, stream function, and velocity potential are introduced. These lead to the powerful principle of potential flow. Although all these fundamentals neglect the viscosity of the flow, and hence drag due to boundary layers, potential flow is nonetheless an immensely helpful design tool and its usefulness in engineering is illustrated.
Main Propulsion Arrangement and Power Generation Concepts
Authors: Stapersma Douwe
Published: April 2017

An overview is given of mechanical, electrical and hybrid propulsion arrangements. The relation between propulsion concepts and power generation is explained and elaborated in energy flow diagrams. A general procedure for analyzing propulsion and power generation concepts is presented, using energy conversion effectiveness and based upon a selection of operational modes and a mission profile reflecting the use of those modes. Potential matching problems when switching between propulsion modes are identified and possible solutions given.
Voyage Planning
Authors: Wood Daniel L.
Published: April 2017

Voyage planning is a safety‐critical risk‐management procedure that encompasses all elements of the planning for and efficient prosecution of a voyage from berth to berth.
Rotational Waves, Wave Turbulence, and Wave Attenuation
Authors: Badulin Sergei I.
Published: April 2017

Elements of dynamics of rotational water waves are given in their connection with the problem of wave attenuation. Both classic results like the rotational Gerstner waves and recently found generalization of these waves–the Ptolemaic flows–are presented.

Theory of wave turbulence starts with the Zakharov's equations for weakly nonlinear water waves. The Hasselmann (kinetic) equation as a basis of statistical description of wind‐generated water waves is introduced and its stationary solutions for direct and inverse cascade, the so‐called Kolmogorov–Zakharov ones, are presented. Recent results on self‐similarity of wind‐driven seas finalize the article.
Regular, Irregular Waves and the Wave Spectrum
Authors: Young Ian R.
Published: April 2017

The following section outlines the basic approaches used to represent and hence predict waves in the ocean. The apparently complex ocean surface can be represented by a characteristic regular wave or by irregular waves leading to a spectral description. Commonly used parametric forms for the spectrum are presented.
Frequency‐Direction Spectra of Wind‐Generated Gravity Waves
Authors: Donelan Mark A.
Published: April 2017

The frequency‐direction spectra of wind‐generated surface gravity waves are summarized in terms of the spectral peak frequency and the stage of wave development (ratio of wind speed at 10 m height to wave phase speed at the spectral peak frequency). The spectra exhibit an enhanced peak, an equilibrium range at frequencies higher than twice the peak, and increased directional spreading at lower and higher frequencies than the peak. Five parameters completely describe the spectra: four are functions of the stage of wave development and the fifth depends on relative (to the peak) frequency. The spectral formulae provided apply in intermediate and deep water. Marine and offshore engineers will find the formulae useful for design and operational calculations. They require only the wind vector and the spectral peak frequency as input.
Generation of Waves by Wind
Authors: Hristov Tihomir
Published: April 2017

The physical mechanism responsible for the existence of ocean waves is described. The wind‐generated ocean surface waves occur from the coupling of two random media, the turbulent atmospheric flow and the compliant ocean surface beneath. The physical analysis here relies on the approximation of surface waves having a small slope, commonly guaranteed in the ocean by the phenomenon of wave breaking. As the wave‐coherent motion in the air is at the core of the wind–wave generation, the dynamic and statistical patterns of that motion are outlined. The dynamic significance of the critical height, a location in the air flow where the mean wind speed matches the phase speed of an underlying wave mode, is pointed out. The article focuses on the characteristic features of the wave‐coherent air flow, such as the discontinuity of the phase at the critical height, which constitute testable predictions of the theory. Experimental evidence in support of wind–wave generation through wave‐coherent flow is presented. Earlier empirical studies on wind interaction with the aerodynamically rough ocean surface are briefly discussed.
Finite‐Depth and Shallow Water Waves
Authors: Groeneweg Jacco , van Dongeren Ap
Published: April 2017

Waves travel from deep water through intermediate depths into shallow regions, where they encounter the coastline, possibly with islands, headlands, estuaries, tidal flats, reefs, and harbors. In the shallow water region, the wave propagation is complex. Horizontal variations in the bathymetry cause shoaling, refraction, wave‐energy redistribution, and breaking, whereas horizontal variations in amplitude cause diffraction. Obstacles cause the waves to reflect. These shallow water processes have been described in detail.

In addition, two typical wave‐induced aspects in the nearshore area have been highlighted. Firstly, gradients in the so‐called radiation stresses act as a force that may generate a set‐up or set‐down of the water level or a current. Secondly, incident waves force the so‐called infragravity waves, which are released from the short‐wave groups in the shoaling and breaking process.