Given the complementary nature of photovoltaic (PV) generation and energy storage, the combination of a solar panel and a battery pack in one single device is proposed. To realize this concept, the PV Battery Integrated Module (PBIM), it is fundamental to analyze the system architecture and energy management. This paper focuses on selecting a suitable architecture among the different options, while also indicating the control strategy that the converters must follow to ensure appropriate performance. Also, several modes of operation for the complete system are introduced to implement energy management. For the selected DC architecture, two case studies, viz. off-grid and peak-shaving for a grid-tied system, were employed to characterize the response of the model demonstrating its utility to perform maximum power-point tracking, excess solar power curtailment, and battery charging and discharging. The proposed control and system architecture prove to be feasible for a PV Battery Integrated device such as PBIM.
Wells in a field offshore South East Sumatra, Indonesia, produce oil at very high rates and water cut. Under these conditions the reservoir is susceptible to fines migration with the associated pore plugging and production decline. Conventional acid treatments to dissolve fines in the near well bore have been effective for limited periods. However after some days or weeks of production, rates have been observed to fall as fines once again migrate, accumulate and plug the formation and gravel pack. Retarded mud acid formulations -that claim fines stabilization- have also been put into practice in an attempt to solve the problem. These formulations have also been ineffective and fines migration remained an unsolved problem. A novel technique to inhibit fines migration through the "Surface Adsorption Polymerization" technique has been used to stabilize the fines around the borehole. The technique is a three-stage process that results in fines being coated with a solid thin polymer film that is stable at high flow (shear) rate locking the fines in place. The validity of the approach has been confirmed with flow tests in cores from the field under study, and has been validated by field results. This paper presents the process followed to implement this technique in the field, case histories and production data of the treated wells. Introduction Formation fines, in general comprised of aluminosilicate particles a few microns in diameter, are found in the majority of oil and gas producing sandstones. Fines become a problem when they swell or detach from the pore wall and migrate through rock matrix with produced fluids. These mobile fines eventually clog in pore throats, plugging the pores and causing a reduction of rock permeability. Factors contributing to the production of fines include exposure to high pH fluids, exposure to fresh (low salinity) water, wettability and high fluid velocity1,2. Quaternary ammonium salts, sulfonated polymers, hydrolyzable metal ions and organosilane products have been used to mitigate fines migration. These chemicals are adsorbed on the rock surface and prevent detachment of fines by forming a protective shield around negatively charged clay particles. These additives have often been termed permanent clay stabilizers, and when compared to inorganic salt stabilizers such as KCl or NH4Cl, they can provide longer-term protection. The fact is that these stabilizers are far from being permanent since they still rely on charge neutralization. The limitations of these treatments are:Charge neutralization does not prevent mechanical dislodgment of particles subjected to high fluid velocity3.Fines with low charge density (feldspars) are not controlled effectively by charge neutralization.Only temporary control is obtained because the polyvalent ions tend to desorb over time as large volumes of fluid are produced. Points 1) and 3) are particularly true in the field of the study, where producing rates of 10,000 to 30,000 BFPD at 90–98% water cut promote mechanical dislodgment of particles and ion desorption.
Concrete currently consists of several types. Among them are Fibrous Concrete, Lightweight Concrete, SCC Concrete, Hollow Concrete etc. All have advantages and disadvantages to each. The use of various types of concrete is adjusted to the needs of construction. In this research, fibrous steel concrete with a combination of silica fume will be the main object to be studied. So far, fibrous concrete has been actively studied in various countries. From the results of previous studies, fibrous concrete can improve the quality of concrete, especially reducing the brittle nature and initial cracking in concrete. While Silica Fume can increase the compressive strength of concrete. The main objective of this study to determine and understand the mechanical properties of concrete with a combination of steel fibre and silica fume such as compressive strength and split tensile strength. The percentage of steel fibre percentage used in this study is from 0 to 3 per cent, while the percentage of silica fume used is l0 per cent by weight of cement. The results of a study are the optimum compressive strength is in the DFl variation with the percentage of silica fume l0 per cent and 0 per cent steel fibre. The use of steel fibre combined with silica fume does not significantly affect the compressive strength. Although it tends to decrease the compressive strength. The strength of tensile strength obtained ranges from 11 to 14 per cent of the compressive strength.
Today, private universities are required to have competitiveness, independence, sustainable reach, integrated information network, in order to maintain the quality of higher education. In fact, not all tertiary institutions have plenty of qualified resources to meet these demands. The emergence of changes in meso policy on higher education standards (SN Dikti) became a substantial influence for private tertiary institutions. Private tertiary institutions are urged to be able to adjust even beyond the standards of tertiary institutions that have been prepared by the central government. The external environment and any amendments to regulations for higher education meso policies may affect the choice of actions and institutional decisions in the operational process of higher education in terms of adapting with and adopting institutions. Exploration of sundry field findings of this study has revealed several aspects to view, it’s how the regulations become a highly influential elements, organizational culture and work culture of other institutions, national, regional and global insights, the influence of inter-institutional cooperation, and assessment of international accreditation.
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