Modelling and Optimization of an Off-Grid Hybrid Power System for Supplying Unmanned Offshore Installations in Eastern Malaysia

In this project, investigation about the potential utilization of hybrid power system in the Malaysian offshore environment is examined. An unmanned offshore installation was selected for the study. The solar and wind energy potentials in Malaysia were investigated and the feasibility study of the project was proved by using meteorological data from the project location at Southeast China Sea. In addition to that, the installation power demand was estimated based on the load profile from Cutter Platform, World first unmanned offshore platform to be operated totally by renewable energy in the North Sea. Moreover, a hybrid power system topology was proposed to supply the loads on-board the offshore installation

Strengthening of Concrete Deep Beams with Extreme Discontinuities Using Near-Surface mounted Composites

Installation of a web opening that fully interrupts the natural load path in concrete deep beams produces regions of extreme discontinuities and reduces the shear strength. This research examined the effectiveness of using near-surface-mounted carbon fiber-reinforced polymer (NSM-CFRP) reinforcement to restore the shear strength of deep beams with extreme discontinuities. The strut-and-tie model (STM) procedures were utilized to develop three different strengthening solutions around the discontinuity regions. A total of eight deep beam specimens (150 x 500 x2700 mm) with a shear span-to-depth ratio of a/h = 0.8 were constructed and tested. One beam was solid. Seven beams had a square opening in the middle of the shear span with an opening height ratio of ho/h = 0.2. Six beams were strengthened with NSM-CFRP around the discontinuity regions. Three-dimensional finite element (FE) models were developed to simulate the nonlinear behavior of the tested specimens. Experimental results were compared to predictions of the FE models and the STM design solutions to examine their accuracy and validity. Installation of the web opening resulted in a 40% reduction in the shear strength. The NSM-CFRP strengthening solutions fully restored the original shear strength, except in two cases where only 93% and 94% of the capacity were restored. The laboratory test results were used to determine the optimal NSM-CFRP strengthening solution. The STM based on provisions of the American Concrete Institute provided realistic and consistent predictions for the nominal strength of the tested specimens with an average predicted-to-measured strength ratio of 1.01±0.09. In contrast, the STM predictions based on provisions of the Canadian Standards Association tended to be conservative with an average predicted-to-measured strength ratio of 0.71±0.29. Predictions of the FE models were sensitive to the mesh size and the concrete constitutive law adopted in the analysis. The inclusion of a bond-slip model between the CFRP and concrete resulted in up to a 5% reduction in the predicted strength. The use of a small mesh size of 15 mm and a “user” concrete constitutive law rather than a “default” law yielded more accurate predictions that were insignificantly different from those obtained from the test

Technical-Economic Analysis in the Application of Series Capacitor Compensation for Distribution Networks

Series capacitor compensation has been widely known as a successful technique of increasing the overall transmission efficiency in power systems by reducing the line reactance by a certain ratio which is defined by the term degree of compensation

Technical-Economic Analysis in the Application of Series Capacitor Compensation for Distribution Networks

Series capacitor compensation has been widely known as a successful technique of increasing the overall transmission efficiency in power systems by reducing the line reactance by a certain ratio which is defined by the term degree of compensation

Estimation of post-harvest losses of Manfalouty pomegranate fruits

Weight loss considered one of the main causes of quality loss in pomegranate fruits during chain marketing. Therefore, this study was conducted on Manfalouty pomegranate (Punica granatum L.) in a private orchard in El Badary, Assiut Governorate, Egypt in 2017 and 2018 to define the various causes of losses during chain handing and estimate it. The fruits harvested at three periods early (September) mid (October) and late season (November). The total losses at harvest were 5.94%, 9.30% and 23.50% for early, mid and late season, respectively. The main cause of losses is due to cracked and infected pests. The total loss of fruits during chain marketing was highest in retail market in comparison with wholesale during early, mid and late season. The main causes of losses due to weight loss and shrinkage fruits. According to data dealing with storage pomegranate fruits at 5±1°C and relative humidity 85-90%, the highest fruit losses found in the third month and this losses due to fruit weight loss and internal chilling injury (brown discoloration) so the storage life of fruit should be two months. DOI: http://dx.doi.org/10.5281/zenodo.405122

A Review on the Dynamic Response of Liquid-Storage Tanks Associated with Fluid-Structure Interaction

Water tanks are considered one of the most important facilities in firefighting systems and municipal water supply. These critical water storage and distribution facilities should remain operable even after a severe seismic event or sustain only damages that can be readily repaired. In recent years, the seismic design of storage tanks has been aimed at fulfilling safety requirements and the environmental impact on society. This paper provides a review of research work related to seismic response of liquid-filled tanks. Major contribution from previous research works related to dynamic behavior of liquid tanks are acknowledged in this review. This paper encompasses the phenomenon of fluid-structure interaction and reviews several equivalent mechanical models for liquid storage tanks that account for this phenomenon. The application of each modeling approach and its accuracy in accounting for the fluid-structure interaction are discussed based on available literature and applicable international standards. It was shown that different equivalent modeling approaches that consider the fluid-structure interaction effects can be used to reduce the computational cost and complexity of liquid-tank systems

Synthesis and antioxidant evaluation of some new sulphadimidine incorporating thiophene moiety

A few new sulphadimidine incorporating thiophene moiety are synthesized. These compounds were assessed by analytical and spectral data. Antioxidant evaluation for the investigated compounds was evaluated by ABTS assay and bleomycin-dependent DNA-damage; the compounds exhibited weak activities

STR-990: SUSTAINABLE GROUTED HELICAL PILES: MATERIALS AND PERFORMANCE

Cementitious materials are widely used as a construction material all over the world. However, cement industry has high environmental impact such as the release of CO2 and the consumption of natural resources for its manufacturing energy. Therefore, reducing cement consumption is vital to achieve sustainable green construction practices. In this study, the effects of using treated oil sand waste (TOSW) as a partial replacement of cement in grouted helical pile applications were investigated. Fresh and hardened properties of the green grout incorporating different percentages of TOSW were evaluated. In addition, a model scale grouted helical pile with the green grout was tested to characterize its performance. The experimental results show that the properties of TOSW grout mixes were comparable to conventional grout and satisfy the strength and construction requirements of grouted piles. Moreover, tested grouted helical pile using the developed mixture exhibited similar geotechnical performance as those installed using conventional grout mix. Hence, TOSW can be implemented in grouted helical pile applications, which would assist in achieving sustainable construction

On–off-Grid Optimal Hybrid Renewable Energy Systems for House Units in Iraq

This paper addresses the optimal sizing of Hybrid Renewable Energy Systems (HRESs), encompassing wind, solar, and battery systems, with the aim of delivering reliable performance at a reasonable cost. The focus is on mitigating unscheduled outages on the national grid in Iraq. The proposed On–off-grid HRES method is implemented using MATLAB and relies on an iterative technique to achieve multi-objectives, balancing reliability and economic constraints. The optimal HRES configuration is determined by evaluating various scenarios related to energy flow management, electricity prices, and land cover effects. Consumer requirements regarding cost and reliability are factored into a 2D optimization process. A battery model is developed to capture the dynamic exchange of energy among different renewable sources, battery storage, and energy demands. A detailed case study across fifteen locations in Iraq, including water, desert, and urban areas, revealed that local wind speed significantly affects the feasibility and efficiency of the HRES. Locations with higher wind speeds, such as the Haditha lake region (payback period: 7.8 years), benefit more than urban areas (Haditha city: payback period: 12.4 years). This study also found that not utilizing the battery, particularly during periods of high electricity prices (e.g., 2015), significantly impacts the HRES performance. In the Haditha water area, for instance, this technique reduced the payback period from 20.1 to 7.8 years by reducing the frequency of charging and discharging cycles and subsequently mitigating the need for battery replacement