Статті в журналах з теми "Protection from ice-wind loads"
Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: Protection from ice-wind loads.
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 статей у журналах для дослідження на тему "Protection from ice-wind loads".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте статті в журналах для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Getz, David, and Jose Palacios. "Design procedures and experimental verification of an electro-thermal deicing system for wind turbines." Wind Energy Science 6, no. 5 (October 6, 2021): 1291–309. http://dx.doi.org/10.5194/wes-6-1291-2021.
Повний текст джерелаАнотація:
Abstract. There has been a substantial growth in the wind energy power capacity worldwide, and icing difficulties have been encountered in cold climate locations. Rotor blade icing has been recognized as an issue, and solutions to mitigate accretion effects have been identified. Wind turbines are adapting helicopter rotor and propeller ice protection approaches to reduce aerodynamic performance degradation related to ice formation. Electro-thermal heating is one of the main technologies used to protect rotors from ice accretion, and it is one of the main technologies being considered to protect wind turbines. In this research, the design process required to develop an ice protection system for wind turbines is discussed. The design approach relies on modeling and experimental testing. Electro-thermal heater system testing was conducted at the Adverse Environment Rotor Test Stand at Penn State, where wind turbine representative airfoils protected with electro-thermal deicing were tested at representative centrifugal loads and flow speeds. The wind turbine sections tested were half-scale models of the 80 % span region of a generic 1.5 MW wind turbine blade. The icing cloud impact velocity was matched to that of a 1.5 MW wind turbine at full power production. Ice accretion modeling was performed to provide an initial estimate of the power density required to de-bond accreted ice at a set of icing conditions. Varying icing conditions were considered at −8 ∘C with liquid water contents of the cloud varying from 0.2 to 0.9 g/m3 and water droplets from 20 µm median volumetric diameter to 35 µm. Then, ice accretion thickness gradients along the span of the rotor blade for the icing conditions were collected experimentally. Given a pre-determined maximum power allocated for the deicing system, heating the entire blade was not possible. Heating zones were introduced along the span and the chord of the blade to provide the required power density needed to remove the accreted ice. The heating sequence for the zones started at the tip of the blade, to allow de-bonded ice to shed off along the span of the rotor blade. The continuity of the accreted ice along the blade span means that when using a portioned heating zone, ice could de-bond over that specific zone, but the ice formation could remain attached cohesively as it is connected to the ice on the adjacent inboard zone. To prevent such cohesive retention of de-bonded ice sections, the research determined the minimum ice thickness required to shed the accreted ice mass with the given amount of power availability. The experimentally determined minimum ice thickness for the varying types of ice accreted creates sufficient tensile forces due to centrifugal loads to break the cohesive ice forces between two adjacent heating zones. The experimental data were critical in the design of a time sequence controller that allows consecutive deicing of heating zones along the span of the wind turbine blade. Based on the experimental and modeling efforts, deicing a representative 1.5 MW wind turbine with a 100 kW power allocation required four sections along the blade span, with each heater section covering 17.8 % span and delivering a 2.48 W/in.2 (0.385 W/cm2) power density.
2
Vagapov, G. V. "Diagnostics of the ice on the strike protection wire." Power engineering: research, equipment, technology 21, no. 4 (December 9, 2019): 104–12. http://dx.doi.org/10.30724/1998-9903-2019-21-4-104-112.
Повний текст джерелаАнотація:
The relevance of the research problem is chose of effective technology of strike protection wire monitoring in span with use of technical system of analysis of technical condition of strike protection wire of 110 kV voltage power line for complex assessment of the impact of both external climatic factors from wind and ice loads and the magnitude of the thermal elongation of the strike protection wire with influence of current during de-icing process. Analysis of the strike protection wire mode and their limiting values of mechanical strength allow evaluation of the effectiveness of events of prevent of accidents and reduce the undersupply of electricity to the end consumers. Visualization of the operative parameters of the strike protection wire in the span of the overhead power line will allow reduce the time to make decisions on the prevention of accidents of lines. Algorithm of monitoring of operative parameters of wires of overhead power lines base on information of longitudinal and transverse angles received from sensors installed directly on the strike protection wire.
3
Cai, Pei, and Bing Tang Yang. "Design and Research of Smart Blades Based on Load Optimization and Power Control." Applied Mechanics and Materials 654 (October 2014): 229–32. http://dx.doi.org/10.4028/www.scientific.net/amm.654.229.
Повний текст джерелаАнотація:
Wind energy is the fastest growing source of energy nowadays. The significant growth of size and weight over the past few decades increase the cost of energy (COE) of wind turbines. Optimization of rapid fluctuating loads, which arise from a variety of sources including turbulence, tower shadow, wind shear and yawed flow, can lower the COE. In this article, the “Active Blade”, changing the local airfoil contour driven by a built-in structure to modify the blade’s aerodynamic performance, designed as a solution to reduce fatigue loads on wind turbines. In this approach, aerodynamic load control devices, combined with sensor, controller and actuator, dynamically control the blade loads. The structure is simple with good high frequency fast response performance. The overload stall protection effect is obvious and fast.
4
Koybakov, S. M., M. Maliktaiuly, S. K. Joldassov, G. A. Sarbasova,, and Zh Yeskermessov. "NEW METHODS TO PROTECT YEAR-AROUND OPERATION CANALS FROM SNOW." NEWS of National Academy of Sciences of the Republic of Kazakhstan 6, no. 444 (December 15, 2020): 102–9. http://dx.doi.org/10.32014/2020.2518-170x.136.
Повний текст джерелаАнотація:
On the canals of year-around operation, severe snowdrifts concentrated on the surface of the ice cover simultaneously affect both thermal and static loads. When ice melts intensively from the lower surface in areas of accumulation of snow masses, and also due to an increase in the static load from snow, longitudinal cracks form on the ice. The snow saturated with water rising up along the cracks, and a gradual sinking of the snow-ice mass occurs. All this leads to decrease in canal capacity, and in some cases to complete blockage of the flow section by snow-ice mass. The purpose of the paper is to find new ways to protect the canal drift and create an impervious canal profile in areas heavily covered in snow. Snow deposition in the canal bed occurs gradually, starting from the edge of canal closest to the snow collection basin side, followed by an increase in the snowdrift shaft in the direction of the wind as snow blizzard arrives to the canal. We propose the method of protecting the canals from snowdrifts by changing the transverse profile of the canal in the sections highly covered by snow. The transverse canal profile is changed by adding a berm to it with a slope coefficient equal to the coefficient the leeward slope and a height equal to the depth of the canal from the leeward slope depending on exact establishing the limit position of the surface of the snowdrifts, at which the canal is blown without snow deposition, regardless of the amount of snow transfer. The proposed methods can be applied in areas of snow transfer on watering and irrigation canals designed for year-around operation.
5
Dawson, TJ, and SK Maloney. "Fur versus feathers: the different roles of red kangaroo fur and emu feathers in thermoregulation in the Australian arid zone." Australian Mammalogy 26, no. 2 (2004): 145. http://dx.doi.org/10.1071/am04145.
Повний текст джерелаАнотація:
Fur or feathers provide protection against heat loads from solar radiation for birds and mammals. The red kangaroo (Macropus rufus) and the emu (Dromaius novaehollandiae) are conspicuous in arid environments of Australia where there is potential for high solar loads. The diurnal D. novaehollandiae feeds in the open yet it has a dark coat with a high absorptivity (83%), which contrasts with that of M. rufus (61%), but M. rufus generally shelters in shade during the day. We examined the effect of coat characteristics on the heat load from solar radiation at skin level. Coat depth and density (thermal conductance or insulation) and the level of penetration of solar radiation into the coat were important determinants of solar heat load. For M. rufus less than 25% of incident radiation reached the body at low wind speeds and this diminished to below 15% at moderate wind speeds. In the modest shade M. rufus seeks on summer days, their heat load from solar radiation appears minimal. Colour differences among M. rufus did not affect thermal load. D. novaehollandiae on the other hand is exposed to the full incident solar load in the open but its plumage provides almost complete protection from solar radiation. Solar radiation is absorbed at the feather surface and the insulation provided by the deep coat prevents heat transmission to the skin.
6
Vitalii V. Khomicky, Borys M. Ostroverkh, Viktor A. Tkachenko, Vladimir A. Voskoboinick та Lidiia M. Tereshchenko. "Іmprovement of protection dam of the мarine approach channel Danube-Black Sea". Environmental safety and natural resources 35, № 3 (17 вересня 2020): 57–77. http://dx.doi.org/10.32347/2411-4049.2020.3.57-77.
Повний текст джерелаАнотація:
One of the important tasks for Ukraine is to restore navigation on the mouth of the Danube Bistre, using it as a European-Asian way from the Baltic Sea to the Black Sea, and then to the East. Restoration of the deep-sea navigation of the Danube-Black Sea River has begun about ten years ago and has been progressing with great difficulty and interruptions. A protective enclosing dam of the Maritime approach channel of the Danube-Black Sea deep-water vessel was built in the water area of the Bystre estuary of the Kiliya Delta of the Danube River. This paper presents the results of mathematical and physical modeling of the improvement and reconstruction of the protection dam of the Maritime approach channel of the Danube-Black Sea deep-sea navigation. Numerical calculations of the transformation of wind waves in the water area near the dam for the most dangerous wind directions in stormy conditions are carried out. For mathematical modeling, the maximum values of wind and wave height were used, which were observed during the entire research period in the area of the dam. Within the framework of refraction theory, wave transformation calculations were performed for the most wave-dangerous directions of wind acceleration, namely, northeast, east, southeast and south wind directions. The results of calculations show that the construction of a protective dam at the exit of the Bystre estuary leads to a significant reduction in wave heights (almost twice) and their lengths by more than 1.5 times, which will ensure a smooth approach and exit of vessels to the Bystre estuary. To assess the characteristics of storm surges and wind waves in the study area was set "hypothetical" storm, when uniform in space and constant in time wind blows over the entire Black Sea. Simulations of wind waves were performed by the 3-step method of nested grids. Calculations were performed for twelve options directly. The morphodynamic calculations showed the areas of circulating near bottom currents inside the dam protected area and the peculiarities of the bottom deformation due to wave motion and storm rise of sea level. Experimental studies on a fragment of the dam model revealed the areas of greatest wave loads, features of wave transformation and pressure fields on the dam ridge. On the basis of theoretical and experimental researches the new step form of the dam which withstands storm wave loads is proposed.
7
Howlader, Abdul, Hidehito Matayoshi, Saeed Sepasi, and Tomonobu Senjyu. "Design and Line Fault Protection Scheme of a DC Microgrid Based on Battery Energy Storage System." Energies 11, no. 7 (July 12, 2018): 1823. http://dx.doi.org/10.3390/en11071823.
Повний текст джерелаАнотація:
Currently, the Direct-Current (DC) microgrid has been gaining popularity because most electronics devices require a DC power input. A DC microgrid can significantly reduce the AC to DC energy conversion loss. However, a power grid may experience a line fault situation that may damage important household devices and cause a blackout in the power system. This work proposes a new line fault protection scheme for a DC microgrid system by using a battery energy storage system (BESS). Nowadays, the BESS is one of the most cost effective energy storage technologies for power system applications. The proposed system is designed from a distributed wind farm smart grid. A total of three off-shore wind farms provide power to the grid through a high voltage DC (HVDC) transmission line. The DC microgrid was modeled by a BESS with a bi-directional DC–DC converter, various DC-loads with step down DC–DC converters, a voltage source converter, and a voltage source inverter. Details of the control strategies of the DC microgrid are described. During the line fault situation, a transient voltage was controlled by a BESS. From the simulation analyses, it is confirmed that the proposed method can supply stable power to the DC grid, which can also ensure protection of several loads of the DC microgrid. The effectiveness of the proposed system is verified by in a MATLAB/SIMULINK® environment.
8
Song, Y. D., Qian Cao, Xiaoqiang Du, and Hamid Reza Karimi. "Control Strategy Based on Wavelet Transform and Neural Network for Hybrid Power System." Journal of Applied Mathematics 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/375840.
Повний текст джерелаАнотація:
This paper deals with an energy management of a hybrid power generation system. The proposed control strategy for the energy management is based on the combination of wavelet transform and neural network arithmetic. The hybrid system in this paper consists of an emulated wind turbine generator, PV panels, DC and AC loads, lithium ion battery, and super capacitor, which are all connected on a DC bus with unified DC voltage. The control strategy is responsible for compensating the difference between the generated power from the wind and solar generators and the demanded power by the loads. Wavelet transform decomposes the power difference into smoothed component and fast fluctuated component. In consideration of battery protection, the neural network is introduced to calculate the reference power of battery. Super capacitor (SC) is controlled to regulate the DC bus voltage. The model of the hybrid system is developed in detail under Matlab/Simulink software environment.
9
McCaughey, Ward, Glenda L. Scott, and Kay L. Izlar. "Whitebark Pine Planting Guidelines." Western Journal of Applied Forestry 24, no. 3 (July 1, 2009): 163–66. http://dx.doi.org/10.1093/wjaf/24.3.163.
Повний текст джерелаАнотація:
Abstract This article incorporates new information into previous whitebark pine guidelines for planting prescriptions. Earlier 2006 guidelines were developed based on review of general literature, research studies, field observations, and standard US Forest Service survival surveys of high-elevation whitebark pine plantations. A recent study of biotic and abiotic factors affecting survival in whitebark pine plantations was conducted to determine survival rates over time and over a wide range of geographic locations. In these revised guidelines, we recommend reducing or avoiding overstory and understory competition, avoiding swales or frost pockets, providing shade and wind protection, protecting seedlings from heavy snow loads and soil movement, providing adequate growing space, avoiding sites with lodgepole or mixing with other tree species, and avoiding planting next to snags.
10
Triest, Jack, Robert Mulvaney, and Olivier Alemany. "Technical innovations and optimizations for intermediate ice-core drilling operations." Annals of Glaciology 55, no. 68 (2014): 243–52. http://dx.doi.org/10.3189/2014aog68a049.
Повний текст джерелаАнотація:
AbstractThe British Antarctic Survey, in collaboration with Laboratoire de Glaciologie et Géophysique de l’Environnement, has in recent years successfully drilled to bedrock on three remote sites around the Antarctic Peninsula. Based on the experience from the multi-season project at Berkner Island (948m depth, 2002–05) we optimized the drill set-up to better suit two subsequent single-season projects at James Ross Island (363m depth, 2008) and Fletcher Promontory (654m depth, 2012). The adaptations, as well as the reasons for them, are discussed in detail and include a drill tent set-up without a trench; drilling without a borehole casing with a relatively low fluid column height; and using a shorter drill. These optimizations were aimed at reducing cargo loads and installation time while maintaining good core quality, productivity and a safe working environment. In addition, we introduce a number of innovations, ranging from a new lightweight cable tensioning device and drill-head design to core storage and protection trays. To minimize the environmental impact, all the drill fluid was successfully recovered at both sites and we describe and evaluate this operation.
11
Wirtz, Andreas, Mohamed Abdulgader, Michael P. Milz, Wolfgang Tillmann, Frank Walther, and Dirk Biermann. "Thermally Assisted Machine Hammer Peening of Arc-Sprayed ZnAl-Based Corrosion Protective Coatings." Journal of Manufacturing and Materials Processing 5, no. 4 (October 14, 2021): 109. http://dx.doi.org/10.3390/jmmp5040109.
Повний текст джерелаАнотація:
Structural elements of offshore facilities, e.g., offshore wind turbines, are subject to static and dynamic mechanical and environmental loads, for example, from wind, waves, and corrosive media. Protective coatings such as thermal sprayed ZnAl coatings are often used for protection, mainly against corrosive stresses. The Machine Hammer Peening (MHP) process is an innovative and promising technique for the post-treatment of ZnAl coating systems that helps reducing roughness and porosity and inducing compressive residual stresses. This should lead to an enhancement of the corrosion fatigue behavior. In this paper, the effect of a thermally assisted MHP process was investigated. The softening of the coating materials will have a direct effect on the densification, residual porosity and the distribution of cracks. The investigation results showed the influence of thermally assisted MHP on the surface properties, porosity, residual stresses, and hardness of the post-treated coatings. The best densification of the coating, i.e., the lowest porosity and roughness and the highest compressive residual stresses, were achieved at a process temperature of 300 °C. A further increase in temperature on the other hand caused a higher porosity and, in some cases, locally restricted melting of the coating and consequently poorer coating properties.
12
ZLOBINA, I. V. "STUDYING THE EFFECT OF THE SCHEME OF EXPOSURE TO MICROWAVE ELECTROMAGNETIC FIELDS ON THE HARDNESS OF THE CURED CARBON FIBER-REINFORCED PLASTIC WITH LIGHTNING-PROTECTION GRID APPLIED ON ITS SURFACE." Izvestia Ufimskogo Nauchnogo Tsentra RAN, no. 4 (December 11, 2020): 12–18. http://dx.doi.org/10.31040/2222-8349-2020-0-4-12-18.
Повний текст джерелаАнотація:
Currently, the use of fiber-reinforced polymer composite materials (PCM), in particular, carbon plastic and fiberglass, is much promising in manufacturing structural elements of aircrafts and wind turbines. In order to increase the resistance of these materials to static electricity and lightning strikes when passing storm fronts, the structure of the PCM includes various lightning protection coatings (LPC). The most common LPC are in the form of copper grids. The fin assembly and planes of aircrafts and also large-sized blades of wind turbines are exposed to cyclic high-amplitude and low-frequency bending loads as well as vibrations. Collisions with solid objects are quite possible. Thus, hardness is one of the key characteristics of PCM that determines their performance properties. Strength and endurance of PCM components can be increased by short-term exposure to a microwave electromagnetic field. The presence of a built-in metallic structure brings additional uncertainty in the tolerance to operating loads by anisotropic PCM, as well as in the process of their interaction with an ultrahigh frequency electromagnetic field. Research was performed on the hardness of carbon fiber-reinforced plastics with built-in LPC using various exposure schemes to a microwave electromagnetic field: from the side of the LPC, from the side opposite to the LPC and sequential processing from both sides. It was found that short-term processing in a microwave electromagnetic field with energy flux density of (17-18)×104mW/cm2 did not lead to any change in the initial hardness of the surface of the samples. However, the uniformity of hardness distribution on the surface of the samples in- creased by 35.8-70%, thus ensuring a more adequate tolerance to loads of different nature. The obtained results can be used in the development of finishing technologies to post-process PCM components and improve the latter’s stability to dynamic loading.
13
Benavent-Climent, Amadeo, David Escolano-Margarit, Julio Arcos-Espada, and Hermes Ponce-Parra. "New Metallic Damper with Multiphase Behavior for Seismic Protection of Structures." Metals 11, no. 2 (January 20, 2021): 183. http://dx.doi.org/10.3390/met11020183.
Повний текст джерелаАнотація:
This paper proposes a new metallic damper based on the plastic deformation of mild steel. It is intended to function as an energy dissipation device in structures subjected to severe or extreme earthquakes. The damper possesses a gap mechanism that prevents high-cycle fatigue damage under wind loads. Furthermore, subjected to large deformations, the damper presents a reserve of strength and energy dissipation capacity that can be mobilized in the event of extreme ground motions. An extensive experimental investigation was conducted, including static cyclic tests of the damper isolated from the structure, and dynamic shake-table tests of the dampers installed in a reinforced concrete structure. Four phases are distinguished in the response. Based on the results of the tests, a hysteretic model for predicting the force-displacement curve of the damper under arbitrary cyclic loadings is presented. The model accurately captures the increment of stiffness and strength under very large deformations. The ultimate energy dissipation capacity of the damper is found to differ depending on the phase in which it fails, and new equations are proposed for its prediction. It is concluded that the damper has a stable hysteretic response, and that the cyclic behavior, the ultimate energy dissipation capacity and failure are highly predictable with a relatively simple numerical model.
14
Ram Ola, Sheesh, Amit Saraswat, Sunil Kumar Goyal, Virendra Sharma, Baseem Khan, Om Prakash Mahela, Hassan Haes Alhelou, and Pierluigi Siano. "Alienation Coefficient and Wigner Distribution Function Based Protection Scheme for Hybrid Power System Network with Renewable Energy Penetration." Energies 13, no. 5 (March 2, 2020): 1120. http://dx.doi.org/10.3390/en13051120.
Повний текст джерелаАнотація:
The rapid growth of grid integrated renewable energy (RE) sources resulted in development of the hybrid grids. Variable nature of RE generation resulted in problems related to the power quality (PQ), power system reliability, and adversely affects the protection relay operation. High penetration of RE to the utility grid is achieved using multi-tapped lines for integrating the wind and solar energy and also to supply loads. This created considerable challenges for power system protection. To overcome these challenges, an algorithm is introduced in this paper for providing protection to the hybrid grid with high RE penetration level. All types of fault were identified using a fault index (FI), which is based on both the voltage and current features. This FI is computed using element to element multiplication of current-based Wigner distribution index (WD-index) and voltage-based alienation index (ALN-index). Application of the algorithm is generalized by testing the algorithm for the recognition of faults during different scenarios such as fault at different locations on hybrid grid, different fault incident angles, fault impedances, sampling frequency, hybrid line consisting of overhead (OH) line and underground (UG) cable sections, and presence of noise. The algorithm is successfully tested for discriminating the switching events from the faulty events. Faults were classified using the number of faulty phases recognized using FI. A ground fault index (GFI) computed using the zero sequence current-based WD-index is also introduced for differentiating double phase and double phase to ground faults. The algorithm is validated using IEEE-13 nodes test network modelled as hybrid grid by integrating wind and solar energy plants. Performance of algorithm is effectively established by comparing with the discrete wavelet transform (DWT) and Stockwell transform based protection schemes.
15
Barrelas, Joana, Ilídio S. Dias, Ana Silva, Jorge de Brito, Inês Flores-Colen, and António Tadeu. "Impact of Environmental Exposure on the Service Life of Façade Claddings—A Statistical Analysis." Buildings 11, no. 12 (December 6, 2021): 615. http://dx.doi.org/10.3390/buildings11120615.
Повний текст джерелаАнотація:
Façade claddings, as the outer protection layer of the building’s envelope, are directly exposed to environmental degradation agents. The façades’ orientation and their distance from the sea, among other location and protection-related factors, influence their vulnerability to climate loads, in particular wind and air humidity. These loads, as well as exposure to air pollution, affect the degradation process of claddings and the durability of façades. Therefore, studying the impact of the environmental exposure conditions on the service life of different external claddings provides useful information on their performance over time, which can support (i) decision-makers in the selection of the best façade cladding solutions and (ii) further research on the impact of climate change on building components. This study covers six types of cladding: rendered façades (R), natural stone cladding (NSC), ceramic tiling system (CTS), painted surfaces (PS), external thermal insulation composite systems (ETICS), and architectural concrete façades (ACF). Three hundred façades located in Portugal are analysed according to three main groups of variables, which characterize (i) the façades, (ii) their degradation condition, and (iii) the environmental deterioration loads and context. The statistical analysis results reveal that the environmental variables affect the cladding degradation process. South-oriented façades present lower degradation conditions than façades facing north. The distance from the sea and high exposure to pollutants add to the degradation conditions, reducing the expected service life of façades. The results reveal that claddings can be organized according to two main groups: the most durable (CTS, NSC, and ACF) and the least durable (R, PS, and ETICS) systems. This study enables a comprehensive analysis of the data, useful to draw conclusions about the influence of environmental exposure conditions on the degradation and service life of façade claddings.
16
Krishnasamy, Samy, and S. Kulendran. "Combined wind and ice loads from historical extreme wind and ice data." Atmospheric Research 46, no. 1-2 (April 1998): 123–29. http://dx.doi.org/10.1016/s0169-8095(97)00055-0.
Повний текст джерела
17
Le, Phuc Duy, Duong Bui Minh, Hoai Banh Duc, Hoan Nguyen Thanh, Minh Doan Ngoc, Tung Nguyen Minh, and Khoi Nguyen Minh. "Simulation on power-flow dispatching cases for Microgrid with PVS and battery energy storage system." Science & Technology Development Journal - Engineering and Technology 2, no. 3 (January 22, 2020): 163–78. http://dx.doi.org/10.32508/stdjet.v2i3.567.
Повний текст джерелаАнотація:
Modern Microgrid (MG) mainly consists of distributed generators (DGs), energy storage systems (ESSs), different loads, and protection systems. Microgrid plays an important role not only to ensure the power supply reliability but also to improve the power quality in distribution network. Moreover, deployment of distributed generators such as Photovoltaic Generation System (PVS), wind turbine generation system, and energy storage systems diversifies operation and control modes of AC microgrid in order to meet local demand response. This paper studies on power-flow dispatching cases for a MG with PVS and Battery Energy Storage System (BESS), which considers the maximum power consumption generated by the PVS and minimizes the power received from the utility grid. Simulation results validate the effectiveness of BESS for actively dispatching power-flow of MG in case the PVSs cannot partially or fully meet the local demand response in peak hours. By using ETAP software, real data of the PVSs are used to do simulation and power-flow calculation for the MG, which is to evaluate the feasibility of power-flow dispatch solutions proposed in this paper.
18
Ramos-Rivera, Johnatan, Harianto Rahardjo, Daryl Lee Tsen-Tieng, Nong Xuefeng, and Fong Yok King. "Mechanical response of the real tree root architecture under lateral load." Canadian Journal of Forest Research 50, no. 7 (July 2020): 595–607. http://dx.doi.org/10.1139/cjfr-2019-0332.
Повний текст джерелаАнотація:
The impact of climate change on tree stability is often associated with a higher risk of windthrow due to higher frequency and greater magnitude of extreme climatic conditions. Higher lateral loads due to an increase in maximum wind and rainfall reduce tree anchorage because of a decrease in soil matric suction and consequently the overall strength in the system of trunk, root, and soil. This study compared the mechanical response of trees with different root architectures using static loading tests conducted in the field and numerical analysis of laser-scanned root systems. For this case, mature trees of Khaya senegalensis (Desr.) A. Juss., Samanea saman (Jacq.) Merr., and Syzygium grande (Wight) Wight ex Walp. were tested and analyzed. The root system models consisted of root system architectures obtained using 3-D laser scanning. A parametric analysis was conducted by varying the modulus of elasticity of the soil (Es) from 2.5 to 25 MPa, and the results were compared with those of the static loading tests to obtain the overall mechanical responses of the root–soil systems. The results showed important dependencies of the mechanical responses of the root–soil system on the root architecture in withstanding the lateral load. The numerical models also allowed estimation of the effective leeward and windward anchorage zones with different soil elastic moduli and rooting architectures to define the extent of the tree root protection zones.
19
Kasymbekov, R. A., N. Y. Temirbaeva, S. O. Nazarov, Y. Zh Osmonov, and Nurzhan Murat. "Methods of Freeze Protection for Fruit Trees by Means of Renewable Energy Sources." E3S Web of Conferences 288 (2021): 01001. http://dx.doi.org/10.1051/e3sconf/202128801001.
Повний текст джерелаАнотація:
As the Earth climate changes, the current horticulture gives rise to an acute issue - protecting fruit trees from spring frosts and their root system from freezing in severe winters with little snow. The authors substantiated the methods of how to protect fruit trees from frost and their root system from freezing, as well as a method of how to control their phenological phases based on the study of the heatmass- exchange intensification in a certain soil area occupied by the root system of a tree with various engineering aids to be designed. The aforesaid method is based on the operation of a heat and cold separator, which makes it possible to intensify heat transfer and expand the area of specific heat loads removed using a coolant - potassium salt brine (aqueous 30% KCL solution). The test results have shown that the coolant heated by the heat of the soil to a temperature of 12°С, gradually moving up at a depth of 0.9 m, heats the soil to 7°С at a depth of 0.5 m and up to 1°С on the surface of the earth at an ambient temperature of up to - 10°С. The heat of the lower soil layers comes up to the surface; in the soil area occupied by the root system, the temperature is redistributed, stabilized in a state that excludes freezing of the root system of the fruit tree. A rational value of the effective head has been determined to be equal to 2200 Н/m2 at the depth of the heated soil surface up to 1 m, with a specific heat flow of about 4•105 W/m2. In addition, a rational flow rate of the coolant is set equal to (1.5 ... 2.5) Gmin to produce more optimal heat transfer and additional body force of the heat and cold separator. The method of controlling the phenological phases of fruit trees by heating or cooling a certain soil area occupied by the root system is possible using an installation that generates power from the renewable resources (solar energy, wind or biogas plant), depending on climatic conditions and terrain.
20
Yoon, Han-Sam, and Won-Bae Na. "Anchor Drop Tests for a Submarine Power-Cable Protector." Marine Technology Society Journal 47, no. 3 (May 1, 2013): 72–80. http://dx.doi.org/10.4031/mtsj.47.3.6.
Повний текст джерелаАнотація:
AbstractSubmarine power cables are widely used for power transmission, such as between mainlands and offshore islands and from offshore wind farms to on-land substations. There are several ways to protect power cables from accidental loads. Protection includes concrete blankets, sand bags, bundles, tunnel-type protectors, and trenching. However, no design standard for power-cable protectors is currently available because of the varieties of cable protection solutions and man-made or natural hazards to submarine power cables. Thus, this paper presents anchor drop tests for a newly designed, matrix-type submarine power-cable protector assembled with reinforced concrete blocks, to make a safety assessment. Marine environments were surveyed at the target site and simulated in the test set-up. A 2-ton stock anchor was selected as the colliding object, and a 25-ton crane was prepared to drop the anchor. Preliminary tests were performed to investigate the effect of soil composition and protector arrangements on the test results. Finally, four field anchor drop test scenarios were designed, carried out, and analyzed, and a safety assessment was made for the submarine power cable. From the tests, it was found that, in addition to falling distances, the soil composition and saturation were significant factors for the settlement depth and damaged areas. Considering the settlement depth of soils, the damaged areas of the concrete blocks, and the damaged state of the pipes (safety zone), all of the test results showed that the mattress failed to protect the power cable from the anchor collision. The deformation, damage, and breakage of the pipe, which simulated the safety zone of the power cable, gave clues as to the reasons for the failure.
21
Hann, Richard, Adriana Enache, Mikkel Cornelius Nielsen, Bård Nagy Stovner, Jeroen van Beeck, Tor Arne Johansen, and Kasper Trolle Borup. "Experimental Heat Loads for Electrothermal Anti-Icing and De-Icing on UAVs." Aerospace 8, no. 3 (March 18, 2021): 83. http://dx.doi.org/10.3390/aerospace8030083.
Повний текст джерелаАнотація:
Atmospheric in-flight icing on unmanned aerial vehicles (UAVs) is a significant hazard. UAVs that are not equipped with ice protection systems are usually limited to operations within visual line of sight or to weather conditions without icing risk. As many military and commercial UAV missions require flights beyond visual line of sight and into adverse weather conditions, energy-efficient ice protection systems are required. In this experimental study, two electro-thermal ice protection systems for fixed-wing UAVs were tested. One system was operated in anti-icing and de-icing mode, and the other system was designed as a parting strip de-icing system. Experiments were conducted in an icing wind tunnel facility for varying icing conditions at low Reynolds numbers. A parametric study over the ice shedding time was used to identify the most energy-efficient operation mode. The results showed that longer intercycle durations led to higher efficiencies and that de-icing with a parting strip was superior compared to anti-icing and de-icing without a parting strip. These findings are relevant for the development of energy-efficient systems in the future.
22
Zhou, Li, Shifeng Ding, Ming Song, Junliang Gao, and Wei Shi. "A Simulation of Non-Simultaneous Ice Crushing Force for Wind Turbine Towers with Large Slopes." Energies 12, no. 13 (July 7, 2019): 2608. http://dx.doi.org/10.3390/en12132608.
Повний текст джерелаАнотація:
When the offshore wind energy industry attempts to develop in cold regions, ice load becomes the main technological challenge for offshore wind turbine foundation design. Dynamic ice loads acting on wind turbine foundations should be calculated in a reasonable way. The scope of this study is to present a numerical model that considers the non-simultaneous ice crushing failure acting on the vertical structure of a wind turbine’s foundation. The local ice crushing force at the contact surface between the ice sheet and structure is calculated. The boundary of the ice sheet is updated at each time step based on the indentation length of the ice sheet according to its structure. Ice loads are validated against two model tests with three different structure models developed by other researchers. The time series of the ice forces derived from the simulation and model tests are compared. The proposed numerical model can capture the main trends of ice–wind turbine foundation interaction. The simulation results agree well with measured data from the model tests in terms of maximum ice force, which is a key factor for wind turbine design. The proposed model will be helpful for assisting the initial design of wind turbine foundations in cold regions.
23
Song, Ming, Wei Shi, Zhengru Ren, and Li Zhou. "Numerical Study of the Interaction between Level Ice and Wind Turbine Tower for Estimation of Ice Crushing Loads on Structure." Journal of Marine Science and Engineering 7, no. 12 (December 1, 2019): 439. http://dx.doi.org/10.3390/jmse7120439.
Повний текст джерелаАнотація:
In this paper, the interaction between level ice and wind turbine tower is simulated by the explicit nonlinear code LS-DYNA. The isotropic elasto-plastic material model is used for the level ice, in which ice crushing failure is considered. The effects of ice mesh size and ice failure strain on ice forces are investigated. The results indicate that these parameters have a significant effect on the ice crushing loads. To validate and benchmark the numerical simulations, experimental data on level ice-wind turbine tower interactions are used. First, the failure strains of the ice models with different mesh sizes are calibrated using the measured maximum ice force from one test. Next, the calibrated ice models with different mesh sizes are applied for other tests, and the simulated results are compared to corresponding model test data. The effects of the impact speed and the size of wind turbine tower on the comparison between the simulated and measured results are studied. The comparison results show that the numerical simulations can capture the trend of the ice loads with the impact speed and the size of wind turbine tower. When a mesh size of ice model is 1.5 times the ice thickness, the simulations can give more accurate estimations in terms of maximum ice loads for all tests, i.e., good agreement between the simulated and measured results is achieved.
24
Fu, Ping, and Masoud Farzaneh. "Simulation of the ice accretion process on a transmission line cable with differential twisting." Canadian Journal of Civil Engineering 34, no. 2 (February 1, 2007): 147–55. http://dx.doi.org/10.1139/l06-109.
Повний текст джерелаАнотація:
Cable rotation caused by ice accretion was specifically modelled and simulated for this paper. Both ice loads and wind-on-ice loads were taken into account during the modelling, and the quantity for the wind-on-ice loads was obtained by integrating air pressure and air shear along the airflow boundary. Air pressure and air shear were both evaluated through time-dependent airflow computations. Two types of overhead transmission line cables, namely, the Bersimis cable and an overhead ground wire, were examined using the new model, and a number of conclusions were drawn. The validity and reliability of the modelling methods were confirmed by comparing the simulation results with those obtained from experimental measurements.Key words: airflow computation, cable rotation, ice accretion, computer modelling, simulation.
25
Донець, Олександр Дмитрович, Олександр Іванович Семенець, Євген Тимофійович Василевський, Олександр Григорович Гребеніков та Андрій Михайлович Гуменний. "КОНСТРУКТИВНО-ТЕХНОЛОГІЧНІ РІШЕННЯ ЗАБЕЗПЕЧЕННЯ СТАТИЧНОЇ МІЦНОСТІ ТА РЕСУРСУ РЕГІОНАЛЬНИХ ПАСАЖИРСЬКИХ ЛІТАКІВ". Open Information and Computer Integrated Technologies, № 82 (19 грудня 2018): 4–26. http://dx.doi.org/10.32620/oikit.2018.82.01.
Повний текст джерелаАнотація:
Ensuring flight safety and aircraft structure lifetime is important today’s problem in development of up-to-date regional passenger aircraft. This paper deals with the aspects of providing static strength and lifetime of regional passenger aircraft. A series of factors and parameters were analyzed, which affect the aircraft static strength, lifetime, such as: fatigue, corrosion, wear, fretting-corrosion, human factor.n To ensure static strength, operational and design loads were determined for the entire range of design speeds and flight altitudes, overloads, aircraft weights and CG positions, fuel weight, cargo weight and various possible combinations of their distribution, taking into account the following: dynamic load and elastic characteristics of the aircraft’s design flying in disturbed air and while landing; dynamic load of the control system structure during maneuvering and under wind gusts; failures and malfunctions of systems that directly affect the strength characteristics. The results of flight tests showed that the An-148 100 / An-158 typical structure under the terms of static strength does not have features and parts that create emergency conditions or are unreliable, and confirmed the correctness of the choice of the established operational limitations presented for inclusion in the Flight Operation Manual. Conditions for operation of the An-148-100 / An-158 family during a design life of 30 years were determined on the basis of a comparative analysis of the corrosion resistance of the aircraft structures, whose service life exceeds 30 years. An-148-100 / An-158 airplanes are designed and manufactured in all-climate version in compliance with all the requirements for anti-corrosion protection. The aircraft used design and technological solutions to protect against loss of strength during operation from weathering, corrosion and abrasion, which allowed to state that the main power elements of the An-148-100 / An-158 aircraft typical structure are protected from reduction or loss of strength in operation for any reason, including weathering, corrosion and abrasion, as well as adequate ventilation and drainage. The provision of static strength and lifetime of regional passenger aircraft is confirmed by static, fatigue and flight tests of airplanes, reflected in technical reports with regard to strength, lifetime and service life of the An-148-100 / An-158 aircraft.
26
Savadjiev, Konstantin, and Masoud Farzaneh. "Probabilistic model of combined wind and ice loads on overhead power line conductors." Canadian Journal of Civil Engineering 30, no. 4 (August 1, 2003): 704–10. http://dx.doi.org/10.1139/l03-026.
Повний текст джерелаАнотація:
There is evidence that extreme ice loads combined with moderately high winds may cause catastrophic damage to overhead power lines and prolonged periods of electrical power outage. In this paper, a probabilistic model for combined wind and ice loads was developed for establishing realistic and conservative criteria for design and normalization. The proposed model combines icing of extreme thickness with a moderate wind speed, Vice, reduced by a reduction factor, kr, with respect to the extreme wind speed, Vmax. The evaluation of kr, which is the main purpose of this paper, is done by means of statistical analysis of samples taken from the same initial distribution of hourly wind speeds, Vh. The size of samples corresponds to the average annual icing persistency period, Tipp, observed in the climatic conditions of Quebec. This period, which was established in an earlier study by the authors using statistical analysis of data from the Hydro-Québec passive ice meter (PIM) network, is evaluated to be on average 144 h/year. It was found that kr ranges from 0.4 to 0.7, mainly as a function of the coefficient of variation (COV) of the initial distribution of wind speeds and the return period prescribed for extreme climatic loads.Key words: combined wind and ice loads, probabilistic model, overhead transmission lines.
27
Wahba, Yohanna M. F., Murty K. S. Madugula, and Gerard R. Monforton. "Limit states design of antenna towers." Canadian Journal of Civil Engineering 21, no. 6 (December 1, 1994): 913–23. http://dx.doi.org/10.1139/l94-097.
Повний текст джерелаАнотація:
The Canadian Standard CAN/CSA-S37-M86 “Antennas, towers and antenna supporting structures” follows a quasi-limit states approach in which the member forces determined for specified loads are multiplied by a unified factor and compared with factored resistances given in CAN3-S16.1-M84. This results in designs basically the same as those resulting from a working stress design with a factor of safety of 5/3. Such structures exhibit a non-linear structural behaviour even under service loads. Thus the effect of ice accretion and direct interaction between wind and ice does not permit the load factors specified in CAN/CSA-S16.1-M89 “Limit states design of steel structures” to be directly applied to antenna supporting structures.In this study, 41 different towers (representing various heights and designed for different ice classes and wind pressures) were analyzed under specified loads and then under a set of factored loads. From the comparison of the design forces in the towers with those calculated according to the existing standard, a set of partial load factors was derived. The new load factors to be used in the 1993 edition of S37 are presented and justified. Key words: antenna towers, guyed towers, ice and wind loads, limit states design, self-supporting towers, working stress design.
28
Ye, Kehua, Chun Li, Fudong Chen, Zifei Xu, Wanfu Zhang, and Junwei Zhang. "Floating Ice Load Reduction of Offshore Wind Turbines by Two Approaches." International Journal of Structural Stability and Dynamics 18, no. 10 (October 2018): 1850129. http://dx.doi.org/10.1142/s0219455418501298.
Повний текст джерелаАнотація:
The offshore wind turbines (OWTs) constructed at the northern sea areas under cold climate are frequently subjected to floating ice loads. It is imperative to reduce the damage owing to the floating ice with some appropriate approaches. The purpose of this paper is to ascertain the effectiveness of the tuned mass damper (TMD) and the ice-breaking cone for reducing floating ice loads on OWTs. The National Renewable Energy Laboratory's (NREL) 5 MW OWT, which is treated as a multibody system with rigid and flexible parts, is adopted as the example model here. The multiple loads taken into consideration in the fully coupled simulation include floating ice and turbulent wind. The aerodynamic load acting on the blades is solved by the blade element momentum method based on a full-field turbulent wind farm generated by the Kaimal spectrum. The Matlock model and the Ralston model are adopted for evaluating the floating ice loads on the cylindrical and conical structures, respectively. The TMD system in the nacelle and the ice-breaking cone on the tower at the mean sea level are the two load reduction approaches of concern in this paper. A weak aeroelastic simulation of the OWT model is conducted. The solution of flexibility effectiveness depends on some accurate mode shapes by the linear modal representation. Finally, Kane's method is used for predicting the motion of the whole OWT. The relevant results reveal some positive effectiveness of the TMD system and the ice-breaking cone for reducing the floating ice load. The displacement of tower top decreases significantly with the utilization of the two approaches. The TMD system has a better performance for the side-side displacement than the fore-aft displacement. By switching the ice failure mode from crushing to bending, the ice-breaking cone reduces the floating load more effectively than the TMD system. It affects equally significantly the fore-aft and side-side displacements.
29
Musatay, Zh M., and I. M. Polyakova. "DETERMINATION OF LOADS FOR CALCULATION OF STRENGTH CHARACTERISTICS OF STRUCTURAL ELEMENTS OF FACADES." Bulletin of Kazakh Leading Academy of Architecture and Construction 81, no. 3 (September 30, 2021): 125–37. http://dx.doi.org/10.51488/1680-080x/2021.3-16.
Повний текст джерелаАнотація:
This article discusses the possible loads that will affect the elements of the facade coatings of buildings. Various types of facade slabs, claddings, ice, wind loads, loads from various types of guides for fastening the slabs are considered. The standard and design loads were determined, taking into account the Eurocodes, the loads for the calculations were selected.
30
Gantasala, Sudhakar, Narges Tabatabaei, Michel Cervantes, and Jan-Olov Aidanpää. "Numerical Investigation of the Aeroelastic Behavior of a Wind Turbine with Iced Blades." Energies 12, no. 12 (June 24, 2019): 2422. http://dx.doi.org/10.3390/en12122422.
Повний текст джерелаАнотація:
Wind turbines installed in cold-climate regions are prone to the risks of ice accumulation which affects their aeroelastic behavior. The studies carried out on this topic so far considered icing in a few sections of the blade, mostly located in the outer part of the blade, and their influence on the loads and power production of the turbine are only analyzed. The knowledge about the influence of icing in different locations of the blade and asymmetrical icing of the blades on loads, power, and vibration behavior of the turbine is still not matured. To improve this knowledge, multiple simulation cases are needed to run with different ice accumulations on the blade considering structural and aerodynamic property changes due to ice. Such simulations can be easily run by automating the ice shape creation on aerofoil sections and two-dimensional (2-D) Computational Fluid Dynamics (CFD) analysis of those sections. The current work proposes such methodology and it is illustrated on the National Renewable Energy Laboratory (NREL) 5 MW baseline wind turbine model. The influence of symmetrical icing in different locations of the blade and asymmetrical icing of the blade assembly is analyzed on the turbine’s dynamic behavior using the aeroelastic computer-aided engineering tool FAST. The outer third of the blade produces about 50% of the turbine’s total power and severe icing in this part of the blade reduces power output and aeroelastic damping of the blade’s flapwise vibration modes. The increase in blade mass due to ice reduces its natural frequencies which can be extracted from the vibration responses of the turbine operating under turbulent wind conditions. Symmetrical icing of the blades reduces loads acting on the turbine components, whereas asymmetrical icing of the blades induces loads and vibrations in the tower, hub, and nacelle assembly at a frequency synchronous to rotational speed of the turbine.
31
Braun, Moritz, Alfons Dörner, Kane F. ter Veer, Tom Willems, Marc Seidel, Hayo Hendrikse, Knut V. Høyland, Claas Fischer, and Sören Ehlers. "Development of Combined Load Spectra for Offshore Structures Subjected to Wind, Wave, and Ice Loading." Energies 15, no. 2 (January 13, 2022): 559. http://dx.doi.org/10.3390/en15020559.
Повний текст джерелаАнотація:
Fixed offshore wind turbines continue to be developed for high latitude areas where not only wind and wave loads need to be considered but also moving sea ice. Current rules and regulations for the design of fixed offshore structures in ice-covered waters do not adequately consider the effects of ice loading and its stochastic nature on the fatigue life of the structure. Ice crushing on such structures results in ice-induced vibrations, which can be represented by loading the structure using a variable-amplitude loading (VAL) sequence. Typical offshore load spectra are developed for wave and wind loading. Thus, a combined VAL spectrum is developed for wind, wave, and ice action. To this goal, numerical models are used to simulate the dynamic ice-, wind-, and wave-structure interaction. The stress time-history at an exemplarily selected critical point in an offshore wind energy monopile support structure is extracted from the model and translated into a VAL sequence, which can then be used as a loading sequence for the fatigue assessment or fatigue testing of welded joints of offshore wind turbine support structures. This study presents the approach to determine combined load spectra and standardized time series for wind, wave, and ice action.
32
Alshannaq, Ammar A., Lawrence C. Bank, David W. Scott, and Russell Gentry. "A Decommissioned Wind Blade as a Second-Life Construction Material for a Transmission Pole." Construction Materials 1, no. 2 (July 7, 2021): 95–104. http://dx.doi.org/10.3390/constrmater1020007.
Повний текст джерелаАнотація:
This paper demonstrates the concept of adaptive repurposing of a portion of a decommissioned Clipper C96 wind turbine blade as a pole in a power transmission line application. The current research program is aimed at creating a path towards sustainable repurposing of wind turbine blades after they are removed from service. The present work includes modelling and analysis of expected load cases as prescribed in ASCE 74 and NESC using simplified boundary conditions for tangent pole applications. Load cases involving extreme wind, concurrent ice and wind, extreme ice, differential ice, broken conductor, and broken shield have been analyzed and governing load cases for bending, shear, and torsion have been examined. Relative stiffnesses of different parts forming the wind blade’s cross section (i.e., shell, web, and spar cap) are determined. The corresponding stresses associated with each part under the governing loads are compared to allowable strength values which are determined from composite laminate theory and modelling of the known laminate structure of the E-Glass FRP material. Stresses and deflections obtained are compared with governing reliability-based design criteria and code requirements. The results of the structural analysis indicate that the wind blade can resist the expected loads with reasonable safety factors and that the expected deflections are within permissible limits. Recommendations are provided for detailing and modification of the wind blade for a power pole application in which crossarm and davit connections are highlighted, and foundation details are emphasized.
33
Goryachev, M. P., M. F. Sadykov, and D. A. Yaroslavskiy. "Method for control the mechanical parameters of overhead power lines based on improved inclinometry." Power engineering: research, equipment, technology 21, no. 3 (November 29, 2019): 160–71. http://dx.doi.org/10.30724/1998-9903-2019-21-3-160-171.
Повний текст джерелаАнотація:
Structural elements of overhead power transmission lines are experiencing both horizontal and vertical loads. Wires and cables are elements of the overhead power line, on which changes in mechanical loads are observed to a greater degree. This occurs due to the change in the tension force of the wire/cable depending on the temperature and the formation of icy-rime deposits on it, as well as fluctuations in wind gusts. The article describes the most common systems and methods for determining the mechanical loads on an overhead power transmission line. A method is proposed for calculating the mechanical loads on an overhead transmission line based on mathematical models of a flexible wire, rope and a model for determining ice deposits on wires, taking into account the rotation of the wire/cable around its axis. A comparison of the improved inclinometry method with the method developed earlier for the case of formation of ice deposits on the S-50 cable has been carried out. A comparison was made on the error in determining the tension of the S-50 ground-wire protection cable using the method developed to control the mechanical parameters of overhead power lines, which takes into account the wire/cable rotation around its axis and the method for determining icy-rime deposits developed earlier. The developed method allows determining the elongation of the wire/cable in the span with one anchor support, as well as the strength of its tension with greater accuracy. However, additional clarification is required due to the influence of the wind, the formation of icy-rime deposits of various shapes, as well as the structural limitations of the wire/cable rotation when attaching it to the support.
34
Sharinkova, O., and A. Anosov. "Strength of structural ice protection for steering and propulsion units." Transactions of the Krylov State Research Centre S-I, no. 2 (December 28, 2020): 31–40. http://dx.doi.org/10.24937/2542-2324-2020-2-s-i-31-40.
Повний текст джерелаАнотація:
Steering and propulsion are one of the most vulnerable elements of ice-going ships. This paper discusses structural ice protection for steering and propulsion units suggested and patented by the authors. This system protects rudder blade from the stern over its whole height. The paper gives the results of strength study for this structure depending on relative size of its elements, their stiffness ratios, as well as on application point and direction of ice load.
35
Rogachko, Stanislav I. "THE PROTEKTION OF ESTUARIES, BAYS, LAKES SHORES FROM DESTRUCTIONS." Transport development, no. 2(3) (October 31, 2018): 149–58. http://dx.doi.org/10.33082/td.2018.2-3.15.
Повний текст джерелаАнотація:
The shores of estuaries, bays and large lakes are exposed to the power of wind waves and drifting ice formations. The intensity of their destruction depends on many natural factors. This unfavorable phenomenon is especially dangerous for settlements that historically were founded in close proximity to the water's edge, as well as for monuments of architecture built in ancient times. Such a problem exists in many countries of the world, it is solved by the erection of various types of coast protection structures that must successfully resist the force of the aquatic environment on the coast. Known me-thods of protecting the long coasts of the seas from destruction by storm waves and drifting ice formations by active and passive protection structures seem unreasonably expensive in cases of their use in estuaries, bays, lakes and re-servoirs. The article presents an innovative technical solution to the active protection of such coasts, characterized by simple construction, low cost, maximum efficiency and durability. This method is protected by the patent of Ukraine.
36
Jeong, Dae Il, Alex J. Cannon, and Xuebin Zhang. "Projected changes to extreme freezing precipitation and design ice loads over North America based on a large ensemble of Canadian regional climate model simulations." Natural Hazards and Earth System Sciences 19, no. 4 (April 17, 2019): 857–72. http://dx.doi.org/10.5194/nhess-19-857-2019.
Повний текст джерелаАнотація:
Abstract. Atmospheric ice accretion caused by freezing precipitation (FP) can lead to severe damage and the failure of buildings and infrastructure. This study investigates projected changes to extreme ice loads – those used to design infrastructure over North America (NA) – for future periods of specified global mean temperature change (GMTC), relative to the recent 1986–2016 period, using a large 50-member initial-condition ensemble of the CanRCM4 regional climate model, driven by CanESM2 under the RCP8.5 scenario. The analysis is based on 3-hourly ice accretions on horizontal, vertical and radial surfaces calculated based on FP diagnosed by the offline Bourgouin algorithm and wind speed during FP. The CanRCM4 ensemble projects an increase in future design ice loads for most of northern NA and decreases for most of southern NA and some northeastern coastal regions. These changes are mainly caused by regional increases in future upper-level and surface temperatures associated with global warming. Projected changes in design ice thickness are also affected by changes in future precipitation intensity and surface wind speed. Changes in upper-level and surface temperature conditions for FP occurrence in CanRCM4 are in broad agreement with those from nine global climate models but display regional differences under the same level of global warming, indicating that a larger multi-model, multi-scenario ensemble may be needed to better account for additional sources of structural and scenario uncertainty. Increases in ice accretion for latitudes higher than 40∘ N are substantial and would have clear implications for future building and infrastructure design.
37
Milošević, Vuk S., and Biserka Lj Marković. "Comparison of Point and Snow Load Deflections in Design and Analysis of Tensile Membrane Structures." Advances in Civil Engineering 2020 (December 7, 2020): 1–11. http://dx.doi.org/10.1155/2020/8810085.
Повний текст джерелаАнотація:
Tensile membrane structures are often used as protective structures in order to provide cover from snow, rain, and direct sunlight. They are widely popular because of their advanced structural and architectural properties. Currently, their application is common at sport stadia and public spaces. There are several types of loads acting on tensile membrane structures, most importantly prestress, snow load, and wind load. However, concentrated loads also act on these structures, but they are frequently neglected during the structural analysis. There is yet no European standard on designing tensile membrane structures that would give guidance on structural analysis and incorporation of point load actions in the analysis. In addition, there is little scientific knowledge on how point loads affect tensile membrane structures. This research aims at revealing whether point loads can produce significant membrane deflections and in such way cause damage to the structure or to the objects underneath the membrane. In order to evaluate their importance, point load deflections are compared to deflections induced by snow load. This was done on a large number of numerical models differing in several parameters. Models represent typical geometries of hypar membrane structures on a square base. Obtained results show that, in many cases, point loads can produce larger membrane deflections compared to the snow load. This finding will have an impact on including the point load actions into standardization of design and analysis procedures of tensile membrane structures in Europe.
38
Villeneuve, Eric, Caroline Blackburn, and Christophe Volat. "Design and Development of an Experimental Setup of Electrically Powered Spinning Rotor Blades in Icing Wind Tunnel and Preliminary Testing with Surface Coatings as Hybrid Protection Solution." Aerospace 8, no. 4 (April 2, 2021): 98. http://dx.doi.org/10.3390/aerospace8040098.
Повний текст джерелаАнотація:
In order to study ice protection systems for rotating blades, a new experimental setup has been developed at the Anti-Icing Materials International Laboratory (AMIL). This system consists of two small-scale rotating blades in a refrigerated icing wind tunnel where atmospheric icing can be simulated. Power is brought to the blades through a slip ring, through which the signals of the different sensors that are installed on the blades also pass. As demonstrated by the literature review, this new setup will address the need of small-scale wind tunnel testing on electrically powered rotating blades. To test the newly designed apparatus, preliminary experimentation is done on a hybrid ice protection system. Electrothermal protection is combined with different surface coatings to measure the impact of those coatings on the power consumption of the system. In anti-icing mode, the coatings tested did not reduce the power consumption on the system required to prevent ice from accumulating on the leading edge. The coatings however, due to their hydrophobic/superhydrophobic nature, reduced the power required to prevent runback ice accumulation when the leading edge was protected. One of the coatings did not allow any runback accumulation, limiting the power to protect the whole blades to the power required to protect solely the leading edge, resulting in a potential 40% power reduction for the power consumption of the system. In de-icing mode, the results with all the substrates tested showed similar power to achieve ice shedding from the blade. Since the coatings tested have a low icephobicity, it would be interesting to perform additional testing with icephobic coatings. Also, a small unheated zone at the root of the blade prevented complete ice shedding from the blade. A small part of the ice layer was left on the blade after testing, meaning that a cohesive break had to occur within the ice layer, and therefore impacting the results. Improvements to the setup will be done to remedy the situation. Those preliminary testing performed with the newly developed test setup have demonstrated the potential of this new device which will now allow, among other things, to measure heat transfer, force magnitudes, ice nucleation, and thermal equilibrium during ice accretion, with different innovative thermal protection systems (conductive coating, carbon nanotubes, impulse, etc.) as well as mechanical systems. The next step, following the improvements, is to measure forced convection on a thermal ice protection system with and without precipitation and to test mechanical ice protection systems.
39
Panteleev, V. I., and А. V. Maleev. "System monitoring intensity of glaze-clear ice generation on wires of overhead transmission lines." Omsk Scientific Bulletin, no. 174 (2020): 74–80. http://dx.doi.org/10.25206/1813-8225-2020-174-74-80.
Повний текст джерелаАнотація:
Improving the reliability and efficiency of power supplying by reducing accidents in electrical networks caused by intense ice and wind loads is an important comprehensive task. The solution of this problem consists of several mainly stages: timely detection of the onset of ice formation, impact on the device for removing ice and frost deposits and efficiency of removing of ice monitoring. This article discusses a system for detecting ice formation based on a fundamentally new technique using the technology of «machine vision». The developed system of ice formation makes identify the thickness of ice wall and indirectly, by the angle of deviation of the wire relative to the horizontal position, to determine the mass of ice deposits and wire sag. Considered monitoring system is located on support in close proximity from the wire and consists of the following mainly elements: an electronic unit, an optical sensor, a solar panel and GSM antenna
40
Rogachko, S. I., H. V. Slobodianyk, and N. B. Dolinskaya. "METHOD FOR ESTABLISHING SHORE PROTECTION STRUCTURES FROM GABION." Bulletin of Odessa State Academy of Civil Engineering and Architecture, no. 80 (September 3, 2020): 84–92. http://dx.doi.org/10.31650/2415-377x-2020-80-84-92.
Повний текст джерелаАнотація:
Abstract. The shores of seas, lakes, bays and reservoirs under the action of wind waves, drifting level ice, rainwater, wind erosion and other factors are subject to intensive destruction. As a result of this, the areas of valuable agricultural land and other lands are reduced. The destruction of the coasts is accompanied by landslides, which reduce the area of settlements where residential buildings, urban buildings, industrial enterprises, park areas, roads and other communications are located. In such cases there is a need for the construction of special protection structures, which will protect coasts from destruction. There are two methods of coastal protection ‒ active and passive. Experience in coastal protection shows, that in many cases, these methods can be successful when applied jointly. The types of structures of shore protection structures are diverse. Therefore, the main task of designers is to choose the most optimal of them, taking into account the climatic, hydrological and engineering-geological conditions of the region construction. The aim of this work is to create a progressive method of construction of shore protection structures on shallow shores of the seas and in shallow reservoirs. This paper considers the existing and innovative designs of shore protection structures made of various materials, the conditions of their use and technical and economic characteristics are analyzed. Based on the analysis, a progressive method of construction of shore protection structures from gabions is proposed. The using of the proposed method for the construction of shore protection structures from a box type gabion will speed up the construction process of such structures, as well as reduce the volume of material at the base, which will lead to a significant reduction in the cost of construction. The mass of gabions in each project should be determined on the parameters of the waves of the design storm in accordance to the recommendations of standards.
41
Ahmad, Samir, and Izhar-ul-Haq. "Wind Blade Material Optimization." Applied Mechanics and Materials 66-68 (July 2011): 1199–206. http://dx.doi.org/10.4028/www.scientific.net/amm.66-68.1199.
Повний текст джерелаАнотація:
In recent years the wind turbine blade has been the subject of comprehensive study and research amongst all other components of the wind turbine. As our appetite for renewable energy from the wind turbine continues to increase, companies now focus on rotor blades which can go up to 80m in length. The blade material not only have to face large aerodynamic, inertial and fatigue loads but are now being designed to endure environmental effects such as Ultraviolet degradation of surface, accumulation of dust particles at sandy locations, ice accretion on blades in cold countries, insect collision on blades and moisture ingress. All this is considered to ensure that the blades complete its designated life span. Furthermore exponential increase in composite blade manufacturing is causing a substantial amount of unrecyclable material. All these issues raise challenges for wind blade material use, its capacity to solve above mentioned problems and also maintain its structural integrity. This paper takes on this challenge by optimizing from the properties, merits, demerits and cost of different possible competing materials. Then the material is checked for its structural integrity through Finite Element Analysis simulation using standards like IEC-61400-1.This paper also shows the future direction of research by elaborating the influence nanotechnology can have in the improvement of the wind blade.
42
Fanney, A. Hunter, Eric R. Weise, and Kenneth R. Henderson. "Measured Impact of a Rooftop Photovoltaic System." Journal of Solar Energy Engineering 125, no. 3 (August 1, 2003): 245–50. http://dx.doi.org/10.1115/1.1591799.
Повний текст джерелаАнотація:
A 35-kW rooftop photovoltaic (PV) system has been installed at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland. The system, located on the flat roof that connects NIST’s Administration Building to its adjoining conference and cafeteria facilities, produced NIST’s first site-generated renewable energy on September 14, 2001. In addition to providing electrical energy and reducing monthly peak electrical loads, the rear surface of each module is laminated to 51 mm of extruded polystyrene enhancing the thermal performance of the roof. A unique ballast system secures the photovoltaic system, eliminating the need for roof penetrations. An instrumentation and data acquisition package was installed to record the ambient temperature, wind speed, solar radiation, and the electrical energy delivered to the grid. Additional solar radiation instruments were installed after determining that the original solar radiation sensor was influenced by reflections from the south-facing wall of the Administration Building’s tower. NIST’s electric utility billing schedule includes energy and peak demand charges. The generation charges vary significantly depending upon the time interval—off-peak, intermediate, and on-peak—during which the energy is consumed. The schedule is divided into summer billing months (June–October) and winter billing months (November–May). During the winter billing months, the distribution, transmission, and generation peak demand charges are based on the greatest power demand imposed by the site on the grid. During the summer billing months, an additional demand charge is imposed to capture electrical demand during the on-peak time interval. This paper summarizes the monthly and annual measured performance of the photovoltaic system. The monthly energy produced by the system is tabulated. The system has provided 35676 kWh of electrical energy during its first year of operation. Conversion efficiencies—computed using solar radiation measurements from a single photovoltaic cell radiation sensor, four thermopile-based radiation sensors located around the perimeter of the photovoltaic array, and a remotely located thermopile-based radiation sensor—are presented. Annual conversion efficiencies of 10.8%, 8.8%, and 7.4% were achieved using cell, module, and foot print areas, respectively. Using the electric utility’s rate schedule, the monetary savings credited to the photovoltaic system is determined by combining the cost of the displaced energy with the reduction in peak demand charges attributable to the photovoltaic system. During its first year of operation, the system has saved $2678 with savings in demand charges, essentially equivalent to savings as a result of displaced energy. Finally, using utility provided data and the Environmental Protection Agency’s (EPA) Environmental Benefits Calculator, estimates are made of the avoided emissions of the photovoltaic system over its projected life span.
43
Clemente, Hiphil S., and Thomas E. Marler. "271 Unidirectional Wind Load Influences Growth, Morphology, and Physiology of Papaya." HortScience 34, no. 3 (June 1999): 489A—489. http://dx.doi.org/10.21273/hortsci.34.3.489a.
Повний текст джерелаАнотація:
Trade winds are a widespread horticultural consideration throughout the tropics. Growth and productivity of most horticultural crops are not optimal on sites that are exposed to these chronic, unidirectional winds. We conducted four container studies on an exposed site, using clear plastic or screening material to provide three levels of wind exposure: 0%, 36%, or 100%. Two studies were conducted with direct-seeding, such that seedling emergence and early growth were determined for 7 weeks. Two studies were conducted using 8-week-old nursery plants that had been grown in a protected nursery. These plants were transplanted to the experimental site and grown for 6 weeks. Cultivars were `Known You 1', `Sunrise', and `Tainung 2'. Full exposure to wind reduced height up to 32%, increased root: canopy ratio up to 36% and exhibited no influence or slightly reduced stem cross-sectional area when compared with full protection from wind. Net carbon dioxide assimilation (Pn) was measured on intervals of about 2 h throughout several 24-h periods. Although the daily pattern depended on cultivar and date, the general trend was for Pn to be unaffected by wind from early to mid-morning, and for Pn of the unprotected plants to decline below that of the protected plants throughout the rest of the day. The Pn of plants receiving intermediate protection was highly variable among the cultivars and dates in relation to the protected and unprotected plants. Moreover, dark respiration of the unprotected plants was greater than the protected plants throughout the entire nocturnal period. The primary influence of wind on growth of young papaya seedlings was a shift in biomass allocation in favor of the stem base and roots.
44
Bęc, Jarosław. "Aerodynamics of guyed masts." Budownictwo i Architektura 1, no. 1 (December 11, 2007): 103–18. http://dx.doi.org/10.35784/bud-arch.2304.
Повний текст джерелаАнотація:
Guyed masts response to wind action, ice load and thermal action has been analysed in this paper. Computational model of wind action based on quasi-steady theory has been applied. It has been assumed that nodal displacements may be expressed as a linear combination of representative mode shapes. Special computer program has been made to allow analysis of such structures. It has been found that the selection of representative mode shapes is very influential on the calculations outcome. The obtained results have been compared with the ones calculated according to patch loads method presented in Eurocode 3. The dynamic part of forces calculated with own method are about half of the ones coming from the standard.
45
Adakole Okpe, Samuel, and Joseph Ejelikwu Edeh. "Analysis, design and construction of gravity offshore structure; state-of-the-art." International Journal of Advanced Engineering, Sciences and Applications 3, no. 1 (February 1, 2022): 12–17. http://dx.doi.org/10.47346/ijaesa.v3i1.74.
Повний текст джерелаАнотація:
Abstract: Offshore platforms are divided into many types which are mainly categorized according to waterdepth in the installation location. However, the design differs for each type to accomplish the target of the operation. But for some case of sea waterdepths and an aggressive environment such as the North Sea, steel ones are not suitable, so the heaviest type called gravity platform having enormous mass is used. This type of platform has its special requirements and procedures for construction and needs special types of construction materials in order to resist the climate factors applied due to the aggressive environment. The paper carefully illustrates how the principal Environmental loads (wind and wave), current forces, loads from ice and loads from earth-quake for (earth-quake prone zones) are deployed to archive the design and construction of offshore concrete gravity platforms. Two design methods (Analysis and Design of Shell structures) and the Tangent Modulus Methods of design of Offshore Concrete Gravity platforms are discussed
46
Shafique, Nouman, Safdar Raza, Hafiz Mudassir Munir, Syed Sabir Hussain Bukhari, and Jong-Suk Ro. "Islanding Detection Strategy for Wind Farm Based on Performance Analysis of Passive Indices Having Negligible NDZ." Applied Sciences 11, no. 21 (October 26, 2021): 9989. http://dx.doi.org/10.3390/app11219989.
Повний текст джерелаАнотація:
Distributed generation (DG) resources integration into power system results in environmental and economic benefits. However, technical challenges may create many problems for the distribution system. Islanding detection is the topmost technical perspective regarding distribution system protection. This paper devised a passive islanding detection strategy that employed voltage phase angle (VPA). The VPA is selected after the performance assessment of 6 passive indices. Comparative study proves that VPA has the best accuracy and sensitivity compared to other indices parameters. The proposed technique is employed on a generic system that easily distinguished islanding situations from non-islanding cases such as load increment, load decrement, capacitor energization, capacitor de-energization, motor starting, motor unloading and various types of faults switching scenarios. The protective method is simple and has a quick interpretation algorithm as compared to other existing methods. The study is carried out on IEEE 1547 general test system in MATLAB/SIMULINK environment. The proposed strategy has nearly zero non-detection zone.
47
Bobryashov, Viktor V., Viktor M. Bobryashov, Anastasiya Bobryashova, and Nikolay Bushuev. "Faultlessness of composite enclosing structures with thin-sheet linings and effective thermal insulation." E3S Web of Conferences 97 (2019): 04068. http://dx.doi.org/10.1051/e3sconf/20199704068.
Повний текст джерелаАнотація:
Fencing composite structures with thin-sheet metal cladding and effective thermal insulation are widely used. They are especially effective in hard to reach, remote, seismic areas, in areas with harsh climates. There is a problem of estimating the real random loading of snow, wind, ice, temperature loads and others according to Roshydromet, when the strength, heat engineering, dielectric, and other structural parameters are random and changes in which from the allowable area lead to failures.The paper provides an assessment of the reliability of enclosing structures of buildings based on quantitative signs of impacts (wind, snow and permanent), as well as the results of statistical evaluation of factory acceptance tests. This paper discusses to exhaust the resource - the strength of the middle layer of the structure during shear.
48
Jian, LIU, WANG Jinning, and WANG Zhiyong. "Detecting the deformation of fast ice by InSAR technology with Sentinel-1A descending and ascending orbits data." E3S Web of Conferences 206 (2020): 03028. http://dx.doi.org/10.1051/e3sconf/202020603028.
Повний текст джерелаАнотація:
Accurate mapping of fast ice deformation can effectively characterize the rheological behavior of fast ice and subsequently improve sea ice model. This study used the Sentinel-1A descending and ascending orbits data to detect the deformations of fast ice in the Baltic Sea. A method for automatically obtaining fast ice edge line by combining interferometric coherence image and SAR amplitude image was proposed. Then, the deformations of fast ice were detected from different incidence angles with the descending and ascending orbits data. The results showed that the deformations in radar line of sight obtained from the descending and ascending orbits data were 38cm and 37cm respectively within the fast ice region of 960km2 in the study area. The continuous strong southwest wind was the principal reason for the deformation, and the deformation direction was dominated by east to west. Moreover, the inner fast ice kept stable and its deformation was smaller due to the protection of outer consolidated ice. The experimental results in this paper showed that the deformation trend and characteristics of fast ice can be better understood by InSAR technology with multi-orbits SAR data.
49
Edelman, Harry, Toni Pakkala, Eero Tuominen, Arto Köliö, Miia Jauni, Matti Pentti, Mihkel Kiviste, Juha Vinha, and Susanna Lehvävirta. "Moisture Safety of Green Facades." Alue ja Ympäristö 48, no. 2 (December 19, 2019): 55–68. http://dx.doi.org/10.30663/ay.83370.
Повний текст джерелаАнотація:
In Nordic climate, climbers covering facades are conventionally removed, although there is no evidence of the actual impact of the climbers on the moisture performance of facades. Such information is needed to support building design and nature-based solutions for climate change adaptation. This study aimed to find evidence on the performance of green facades from the physical and life-cycle engineering perspectives of buildings by testing double-skin green facades in laboratory and field conditions. First a mature thicket creeper was grown on a steel mesh over 100 days, and it was exposed to rain and dry periods by accelerated weathering equipment in a laboratory. Then the leafless creeper was exposed to rain cycles on a rooftop in natural conditions. The results indicated the high protective capacities of the climber during the leaf season, but even during the winter season (without leaves) protective performance was measured in laboratory and natural conditions. In conclusion, double-skin green facades provide effective protection from wind-driven rain while the distance between the green structure and the load-bearing wall impacts the relative humidity levels, and the drying process of the load-bearing wall. Thus, moisture safety can be improved with a double-skin structure with ventilation and access for maintenance.
50
Zhang, Ye-Wei, Jian Zang, Tian-Zhi Yang, Bo Fang, and Xin Wen. "Vibration Suppression of an Axially Moving String with Transverse Wind Loadings by a Nonlinear Energy Sink." Mathematical Problems in Engineering 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/348042.
Повний текст джерелаАнотація:
Nonlinear targeted energy transfer (TET) is applied to suppress the excessive vibration of an axially moving string with transverse wind loads. The coupling dynamic equations used are modeled by a nonlinear energy sink (NES) attached to the string to absorb vibrational energy. By a two-term Galerkin procedure, the equations are discretized, and the effects of vibration suppression by numerical methods are demonstrated. Results show that the NES can effectively suppress the vibration of the axially moving string with transverse wind loadings, thereby protecting the string from excessive movement.