Environmental Load Factors Research Articles

Analysis of lateral dynamic response characteristics of drilling riser during installation of deep-water Christmas tree

In this research, in order to investigate the safety risk of drilling riser during deep-water Christmas tree lowering process and determine the basic parameters for the safety calculation of the upper part of the Christmas tree, wave-current force calculation method is explained based on modified Morison equation. According to differential element method, the dynamic equations of vertical and horizontal bending of riser under wave and current conditions are derived and equation solution method and calculation stability conditions are analyzed. By combining the upper and lower boundaries of riser during Christmas tree connection and environmental load factors, dynamic responses of riser under different wave, top tension, platform drift, operating water depth and other parameters are investigated. The obtained results show that maximum lateral displacement, corresponding water depth and bending moment of riser as well as the amplitude and period of displacement fluctuation at riser bottom are increased with the increase of wave velocity and water depth. It is also found that increase of top tension reduced the maximum lateral displacement of riser and increased corresponding water depth, but excessive tension increased the fluctuations of displacement and bending moment at riser bottom. Increase of platform drift increased maximum lateral displacement fluctuation range, bottom string displacement and bending moment of the riser and decreased corresponding maximum displacement water depth. Drift is found to increase the fluctuations of dynamic parameters at riser bottom. Increase of operating water depth increased riser maximum lateral displacement and decreased the period and amplitude of bottom bending moment fluctuations; also, maximum water depth position approached to "1/3" position on sea surface.

Wind Load Distribution in Float Photovoltaic System

This paper investigates wind load distribution in float PV plants. Wave and wind load are dominant environmental load factors in determining design load in float PV plants. In particular, wind load is determined based on the numerical analysis results. The literature indicates that several input parameters exist, such as inlet angle and space between PV modules. An exemplary structure with ten arrays of PV modules was generated in this study. To investigate the wind load distribution in a float PV plant, the computational fluid dynamic (CFD) analysis was conducted with variables including wind direction (inlet angles) and three wind speeds (36.2, 51.7, and 70 m/s) in PV modules in the floating structure. Based on the numerical analysis, the wind load distribution of PV modules can be characterized with respect to the inlet angle and wind speed. The numerical results show that the wind loads in the central arrays are dominant.

Kehandalan Struktur Anjungan Lepas Pantai Terpancang Empat Kaki di Perairan Natuna

The design of offshore platforms in Indonesia generally uses Working Stress Design (WSD) method rather than Load and Resistance Factor Design (LRFD) method. Whereas the LRFD method produces designs that better describe real conditions with load and capacity factors. The load and capacity factors are obtained from consideration of the uncertainty or randomness of their values. One of the load factors used is the environmental load factor. The environmental load factor of LRFD method is obtained based on environmental characteristics not in Indonesian waters. There are differences in the environmental characteristics of each water. Uncertainty of environmental loads in the offshore platforms design is wave height, current velocities, and wind speed. To get a structure designed according to the characteristics of the waters in Indonesia, an environmental load factor is needed in accordance with the characteristics of Indonesian water. To achieve that, structural reliability analysis is needed. S tructure s reliabilty represents the possibility of the structure's performance criteria being met which is expressed by the reliability index. The reliability index of structures designed using the WSD method used as a reference for LRFD method. In this study, reliability analysis was carried out using the reserve strength ratio value from the pushover analysis on WSD method. The reliability index of the structure model is 4.10. This value is categorized as high reliability . Th is results can be used as a reference to determine the environmental load factor of Indonesia n water in the future.

Can Microbials Enhance Commercial Calves’ Gut Integrity, Immunity and Health?

Supplemental Microbials (SM) could offer commercial young dairy calves with healthy subjects to enhance gut microbial diversity and host health if calves are managed properly and optimally. The possible helpfulness of SM, however, must not be overstated and overemphasized. The major aim of this editorial was to address whether SM is practically workable in preventing digestive disorders namely diarrhoea. Another aim was to underline the possible efficacy of such products in enhancing calf health and immunity. Protecting newborn calves against infectious diseases and concurrently, improving their health and growth in early life is strictly related to herd economics and production sustainability. Diarrhoea is the most prevalent infectious disease, causing calf morbidity and mortality worldwide. Supplementing dairy calf diets (i.e., milk or starter) with potentially beneficial microorganisms such as bacteria and yeast has been attempted to improve the gut microbial ecosystem and optimize nutrient assimilation and immunity. However, infectious diarrhoea still remains a major problem in many dairy and beef farms around the globe. Since diarrhoea has a multi-factorial nature, it seems that the possible efficacy of SM depends on the environmental and management conditions in which the calves are raised. The rearing system (e.g., individual vs. group housing), diet, environmental microbial load and other management factors are involved in the incidence of diarrhoea. Therefore, using probiotic products may interact with such factors, thus influencing their effectiveness and likely causing inconsistencies concerning probiotics’ usefulness in commercial dairy farms.

Study on Steady-State Temperature Rise Characteristics of Motor Heat Balance under Load Rate

The influence of load rate and other factors is not considered in the temperature rise monitoring process of traditional motor, which will lead to the wrong diagnosis of motor health status. In this paper, the characteristics of motor temperature rise under different ambient temperatures and different load factors are studied. Taking an 11 kW three-phase asynchronous motor as an example, the temperature rise model of the motor is based on the finite element method established using ANSYS software. The thermal conductivity coefficient and surface heat dissipation coefficient of each part of the motor are determined. According to the electromagnetic field calculation, the motor loss distribution is obtained, and the temperature rise distribution curve of the motor is obtained by the simulation of the three-dimensional steady temperature field of the motor. In this paper, the temperature rise variation law of the motor considering the influence of environmental temperature and load factors is proposed, and combined with the temperature rise threshold curve of the motor under different load rates, a dynamic threshold judgment system is established to accurately warn the motor of overheating under any load rate. When the motor’s health status changes after running for a long time, it provides an important theoretical basis for accurate diagnosis of the motor’s health status.

Determination of LRFD environmental load factor in the java sea for unbraced monopod structures using reliability analysis

Case studies were carried out for unbraced monopod structures located in the Java Sea by reviewing the value of the reliability index. This sea has a depth of 33 meters and a 100-yr wave height of 6.29 meters. The structures are designed optimally with a unity check ratio of 1.00 using API RP 2A WSD and API RP 2A LRFD standards under storm condition, assumed to be unmanned. For LRFD criteria, the value of the environmental load factor is varied, namely 1.35, 1.20, 1.10, and 1.00. Collapse analysis using static pushover analysis of the model produces a minimum RSR value meeting the minimum criteria for un-manned structures of 1.6. The reliability analysis process uses the First Order Reliability Method II (FORM II). The structural reliability index value has met the minimum criteria issued by DNV of 3.71 for the structure that is designed using the environmental load factor of 1.35. It can be concluded for unbraced monopod structures designed in the Java Sea, the environmental load factor value of 1.35 is following the minimum reliability index value proposed by DNV.

System-based calibration of offshore Malaysia environmental action factors for the ISO 19902 PETRONAS offshore fixed platforms

Previously, the action factors, which are generally used in the region of Malaysia is based on the data from the Gulf of Mexico (GoM) or the North Sea, where the environmental condition is much harsher than the offshore Malaysia. Direct application of the high load factors in these regions can result in a waste of economic resources. Based on a reliability-based Load and Resistance Factor Design approach, the current study is carried out for the provision of system-based approach for the calibration of Offshore Malaysia Annex Extreme Environmental Action Factors based on the data from Malaysian waters. With the accessible SEAFINE and HYCOM hindcast database, long-term statistics of extreme environmental load have been derived for six platform locations in Malaysian waters, following the response-based Load Statistics Module (LSM) process. The Generic Load Model (GLM) including the wave-in-deck forces, which has been employed for transferring the wave motion statistics to structural response statistics, is developed in the paper. The structural resistance uncertainty is characterised by the minimum reserve strength ratios (RSRs) derived from a theoretical model that relates with environmental load factor. A structural system reliability analysis based on the FORM method has been performed for a range of minimum values of theoretical RSR for jacket structures fully designed to ISO Code 19902. Partial action factors associated with extreme environmental loads are calibrated to achieve a target reliability level in terms of reliability index.

Analysis of the Environmental Load Factor on the Economic System of the Region

The article considers different approaches to correspondence analysis of economic and environmental regional factors. The analysis is based on the ecological Kuznets curve and some investigations of regional ecological and economic problems. The empirical analysis demonstrates a stable correlation between environment exploitation indicators (atmospheric air and sewage pollution) and gross regional product value as well as high level of regions’ differentiation based on ecological indicators that can be explained by low level of regions’ economics development and, in addition, its rent-seeking nature. An in-depth analysis of some regions showed a correlation between sectorial structure of the region’s economy and environment pollution: manufacturing and mineral extraction have the most impact. These conclusions conform to the dynamic of the ecological Kuznets curve: the growth of traditional sector of economy has more significant impact on standards of living rather than environmental factors. The intensity of environment exploitation and dynamic of environment polluting define the need of regulatory leverage by the government through economic and institutional factors due to prevention of irreversible impact on region’s environment.

Examination of oxidation resistance of Mg2Si thermoelectric modules at practical operating temperature

Magnesium silicide (Mg2Si) is as known a thermoelectric material with low environmental load and high power factor around 400 °C. It should be performed to solve the problems. i.e., its low oxidation resistance and high chemical activity. In the current decades, oxidation resistance of Mg2Si has been researched because it is essential to thermoelectric power generation. The oxidation factor of Mg2Si still remains unexplained. In this paper, forming process of oxidation resistant layer of Mg2Si powder is examined by thermal analysis and X-ray diffraction. It was revealed that Mg2Si induced to compound with elements of the atmosphere. The oxidation process of Mg2Si was related to humidity without oxide, since oxidation layer absorbs humidity and forms a magnesium hydroxide (Mg(OH)2) layer. The Mg(OH)2 layer was decomposed at 400 °C, which is the temperature required for practical use of thermoelectric generation. It is found that a humidity resistant layer should be formed on the surface of Mg2Si.

A forecast model of freak wave generations in deep water

In ocean engineering designs, random extreme events are the most difficultly determined environmental load factors. Appearances of freak waves in the normal sea states are just such events. To reduce their potential destruction of marine structures, a forecast model is studied to predict whether freak waves occur in the wave propagation. In this model, the modified fourth-order nonlinear Schrödinger equation is employed as the deep-water wave model, which controls the evolution of complex wave envelopes. The measured wave train is set as its initial condition which needs to be changed into its corresponding complex wave envelope by use of the Hilbert transform method to be input into the wave model. During the evolution of complex wave envelope, its corresponding wave heights are estimated and compared with the definition of freak waves. If a freak wave is captured, its occurrence position and time are given. Three cases of observed, simulated and laboratory wave trains as initial conditions are performed to predict the generation of freak waves. Results show that measured wave trains can be simply and accurately input into this forecast model through the Hilbert transform method and this model can predict the generation of freak waves within some space and time in its traveling. In addition, larger groups than usual group height or length increase the probability of freak wave generation. This forecast model may provide marine activities with a safety warning in some open seas.

Determination of environmental load factors for ISO 19902 code in offshore Malaysia using FORM structural reliability method

Environmental load factor, used for the design of Jacket platform design in Malaysia, are based on calibration of platforms located in Gulf of Mexico and North Sea. This load factor is assumed to be high for locations where moderate climate governs i.e. regions lying near equator like Malaysia which is at 7° north of the equator. For Jacket platforms, safety can be achieved by taking into consideration of hazards produced by rare events of wave, wind and current. Environmental loads are not like live loads acting on land-based structure but are more severe due to unpredictable weather conditions. These environmental loads can act with unexpected severity on offshore structures. Material strength of tubular components and joints plays significant role against risk. The resistance can also be reduced because of damage to Jacket, continuous action of wave forces causing fatigue and corrosion. Four platforms from three different regions of Malaysia were selected for the reliability analysis. Probabilistic techniques were used to evaluate and estimate the load and resistance uncertainty. FORM method of reliability was used for structural reliability analysis of Jackets. Modified environmental load factor is proposed for offshore Malaysia considering component, joint and system reliability analysis based on calibration.

Development of Partial Environmental Load Factor for Design of Tubular Joints of Offshore Jacket Platforms in Malaysia

The reliability analysis methods have been effectively applied to develop load and resistance factor design (LRFD) codes, such as the ISO 19902, that provide optimum structural safety taking into account the uncertainties of both the load and resistance parameters. Although, these methods have been developed since the early 1960's their application in the design of offshore structures is still not extensive. This paper presents the procedure for reliability analysis and evaluation of the environmental load factor for design of tubular joints of offshore platforms in Malaysia, for the proposed ISO. The uncertainties affecting the joints' resistance and loading were investigated and their statistical parameters pre- sented. The reliability indices of a platform designed using both API RP2A - WSD and ISO 19902 were evaluated and compared. The partial environmental load factor of 1.29 was obtained, which provides a significant reference towards the adoption of ISO in Malaysia.

Research on Green Building Material Assessment Factors and Eco-Efficiency Issue

Due to global climate changes, Earth sustainability issues have become topics of international attention. The frequency of abnormal weather occurrences and disasters around the world has doubled and the health of the environment has been deteriorating, causing catastrophes around the world. All countries must have a prudent response to this situation. The environmental topics debated globally have changed from passive discussions about environmental protection and energy consumption to more proactive dialogues on sustainable cycles and LOHAS. Taiwan has actively proposed relevant environmental responsive measures, including plans for ecological cities, green buildings, and green building materials (GBMs). GBMs are the basic factor of environmental building projects and they have the most extensive scope of applications, as they have a direct effect on human health and are the key to the Earth’s sustainability. This research summarized international sustainability assessment systems, international green building material labels, and relevant building material assessment mechanisms, in order to summarize and integrate a variety of factors with the life cyclic assessment (LCA) of the ISO14040 series as the axis for establishing a preliminary green building material assessment system. In addition, the Fuzzy Delphi Methods was employed for analysis to discuss the green building material environmental load (Ln) factor and the green building material quality (Qn) factor. According to the research and analysis results, this research established the GBM Eco-Efficiency Assessment System in the context of climate change, to be used as the basis for subsequent research on GBM eco-efficiency standards. Using efficiency as a starting point, this research hoped to achieve a win-win strategy of balancing human health with the Earth’s sustainable development.

Towards monopod design criteria for uniform reliability

The structural reliability of braced and unbraced monopod platforms is investigated under storm overload. A wide spectrum of monopod geometries is designed for Australian North West Shelf (NWS) metocean conditions using API RP2A-LRFD with the usual environmental partial load factor γ E = 1.35. Ultimate strengths and safety indices are then determined. Particular features of monopod platforms result in the probabilities of failure frequently being higher than recommended values for new unmanned platforms, although the values vary strongly with topside weight. Increasing the load factor significantly to γ E = 3 is found to achieve commonly acceptable safety index values β > 3 with much greater uniformity in reliability. The results are particularly relevant for the design of NWS offshore infrastructure and in ensuring its longterm integrity, given the strong prevalence of minimum platforms and the severe long-term wave conditions in the region. These effects were highlighted by the structural failure of a relatively new braced monopod platform in 1996 during a tropical cyclone [Buchan, S.J., Black, P.G., Cohen, R.L., 1999. The impact of tropical cyclone Olivia on Australia's Northwest Shelf. OTC 10791, Proc. OTC, Houston].

Designation of Environmental Capacity and Load Factors at Regional Scale

Though sustainability is very important concept, it is very difficult to define it quantitatively. This study aims to quantify regional environmental capacity and long-term growth by using koku of rice data. The results show that metropolitan region has suffered heavy environmental loads. The model to investigate environmental load factors indicates that the environment preservation and regional growth are both side of the same paper, a kind of antinomy. The effect on regional environment and growth by disasters and infrastructure are also examined by using this model.

Life Cycle Assessment Estimation for Eco-Management of Co-Generation Systems

A LCA (life cycle assessment) scheme for any industrial activity system is introduced to estimate the quantitative load on the environment with the aid of the NETS (numerical environment total standard) method proposed by the authors as a numerical measure. Two kinds of environmental loads respecting fossil fuel depletion as input resources to the system and global warming due to CO2 emission as output are taken into account in the present eco-criterion, in which the total eco-load (EcL) value is calculated from the summation of respective environmental load factors on the whole process in a life cycle of the system. This NETS method is applied to eco-management co-generation systems, in which a computer-aided output navigator proceeds the LCA estimation with ICON and Q&A communication. An operation scheme most friendly to the environment with a minimum EcL value, i.e., an eco-operation scheme, is derived from the optimization theory.

Variability of environmental loads

The oceanographic and meteorological data bases presently available at the Canadian Climate Centre, Environment Canada are used to produce plots for the coefficient of variation of annual and monthly environmental loads due to winds and waves. This parameter is extremely important for the calculation of design risks and is linked to the selection of the environmental load factors in design codes. Extreme wind loads and wave loads induced by both drag and inertia are examined for the East Coast, the West Coast and the Beaufort Sea areas of Canada.