Avanti Publishers
Not a member yet
711 research outputs found
Sort by
Matrix Acidizing Optimization for Screened Sandstone Formation at High-Rate Gas Well of Deepwater GWK-8
Get PDFDeepwater GWK-8 is a gas well in deep sea with 1500 meters water depth and a deviated well with a sandstone formation that has good permeability, potentially high-rate gas well, high reservoir pressures, and large reservoir size. This well is expected to immediately ramp up production at optimal productivity through Floating Production Storage and Offloading (FPSO) in Makassar Strait. For a gas well at deep-water exploration must be commercially viable, it needs to achieve optimal production rate. Gas production initially was not meet the expectations, so it needed to be optimized by one of stimulation method that suitable for this well is matrix acidizing. Sandstone formation is screened by Shape Memory Polymer (SMP) sand control system and matrix acidizing is carried out to optimize the deliverability of gas well by dissolving formation impurities and normalize damage in the wellbore. Methodology of this study begins with collecting data on reservoir data, formation lithology, completion, and well-testing. The optimization of matrix acidizing process is based on initial well-testing results where skin (s) of pre-acidizing is 46 with a permeability (k) is 51.4 mD. The matrix acidizing process uses mud acid (HCl-HF) for upper zone of deepwater GWK-8 that has been installed Shape Memory Polymer (SMP) sand control at the pay zone area. Based on well-testing of post-matrix acidizing, successfully proven in reducing the skin number (s) from 46 to 10, increasing permeability (k) from 51.4 mD to 120 mD, and increasing productivity from 30 MMSCFD to 44 MMSCFD
Tomato Crop Health, Yield, and Greenhouse Soil Conditions after 17 Years of Repeated Treatments of Biofumigation and Solarization
Get PDFThe combination of biofumigation and solarization is known as bio-solarization. An experiment was performed from 2003 to 2019 in a greenhouse at INTA San Pedro, Buenos Aires province, Argentina (33°44'12.7"S 59°47'58.2"W). Treatments (TRAT) were applied every two years. TRAT evaluated were: 1=Control; 2= Solarization, 3= Biorot, a succession of organic amendments (chicken manure, broccoli, chicken manure, broccoli, tomato, and pepper crop debris, mustard, tomato crop debris, broccoli, tomato crop debris), 4=Biobras based only on the use of brassicas (rapeseed, broccoli, mustard, and Brassica campestris). Treatments were carried out in spring or summer so that a late-season tomato crop could be grown after them. The tomato hybrid planted was Superman (Petoseed), except for the last season where the hybrid used was Rodeo (BHN). Fungal pathogens controlled were Pyrenochaeta lycopersici, Fusarium solani, Sclerotium rolfsii, and Sclerotinia sclerotiorum, and nematodes like Nacobbus aberrans, Helicotylenchus and Criconemella. Fungi of Aspergillus genera were observed growing on death sclerotia of Sclerotinia sclerotiorum and Sclerotium rolfsii in Biobras and Biorot. Tomato plants in control showed a higher percentage of dead plants, root rots, and lower root dry matter at the end of each crop. Solarization alone without adding organic matter reduced this parameter in the soil and showed more death plants and less yield than Biobras and Biorot. Tomato and pepper crop debris used as biofumigants produced high yield values and adequate pathogen control. Biofumigation in combination with solarization is an effective technique for managing soil-borne pathogens in greenhouses and is being adopted by horticultural growers in Argentina
Use of Crop Rotations, Cover Crops and Green Manures for Disease Suppression in Potato Cropping Systems
Get PDFCrop rotations and the inclusion of cover crops and green manures are primary tools in the sustainable management of soil-borne diseases in crop production systems. Crop rotations can reduce soil-borne disease through three general mechanisms: (1) serving as a break in the host-pathogen cycle; (2) by altering the soil physical, chemical, or biological characteristics to stimulate microbial activity and diversity; or (3) directly inhibiting pathogens through the release of suppressive or toxic compounds or the enhancement of specific antagonists. Brassicas, sudangrass, and related plant types are disease-suppressive crops well-known for their biofumigation potential but also have other effects on soil microbiology that are important in disease suppression. The efficacy of rotations for reducing soil-borne diseases is dependent on several factors, including crop type, rotation length, rotation sequence, and use of the crop (as full-season rotation, cover crop, or green manure). Years of field research with Brassica and non-Brassica rotation crops in potato cropping systems in Maine have documented the efficacy of Brassica green manures for the reduction of multiple soil-borne diseases. However, they have also indicated that these crops can provide disease control even when not incorporated as green manures and that other non-biofumigant crops (such as barley, ryegrass, and buckwheat) can also be effective in disease suppression. In general, all crops provided better disease control when used as green manure vs. as a cover crop, but the addition of a cover crop can improve control provided by most rotation crops. In long-term cropping system trials, rotations incorporating multiple soil health management practices, such as longer rotations, disease-suppressive rotation crops, cover crops, and green manures, and/or organic amendments have resulted in greater yield and microbial activity and fewer disease problems than standard rotations. These results indicate that improved cropping systems may enhance productivity, sustainability, and economic viability
Evaluation of Mine Geological Environment Quality Based on Fuzzy Analytic Hierarchy Process
Get PDFThe study of mine geological environmental quality evaluation methods has always been an important topic. Taking the mining geological environment of Muping District, Shandong Province as the research background, and based on the fuzzy analytic hierarchy process, a hierarchical structure model of the quality evaluation index of the mine geological environment in the study area was established, the relative importance of the 14 rating levels was estimated, and the weights were calculated. And sorting, establish a mine geological environment quality evaluation index system; then, according to the calculated comprehensive threshold value, establish a comprehensive evaluation grade of the mine geological environment. The results of the study show that the degree of environmental pollution (air, soil, water), vegetation coverage, topography and landform are the main factors for the evaluation of the geological environmental quality of the mines in the study area, and their weights are 0.3114, 0.1743, and 0.1184 in order. According to the principle of the maximum degree of membership, the mine geological environment quality is determined to be a good grade. Through the verification of the survey results of the mine geological environment on-site, the results show that the weights calculated by this method are reasonable, and the theoretical analysis and evaluation results obtained are in good agreement with reality. This method is worthy of popularization in the mine environment assessment work. Decision-making and governance provide decision-making support services
Identification of Faulty Operation in Photovoltaic Panels
Get PDFIncreasing the efficiency of photovoltaic panels (PV) is one of the important goals of researchers worldwide in the field of renewable resources. The important results obtained in the case of finding new materials for the manufacturing of the panels to obtain the highest possible conversion efficiency must be doubled by research for developing methods for efficient real-time monitoring of PV operation in order to rapidly or in advance identify possible failures.
This paper looks for some types of failures and how they can be identified as quickly as possible from the information coming from different sources, the most important being the PV monitored parameters, the PV control system parameters, and from different cloud services.
One way to identify different types of failures is to use machine learning (ML) methods. In applying these methods, an important thing is the availability of a great number of good training data sets. In order to obtain such data sets, this paper aims to create a model of PV using Matlab, which is fed with both real data and data synthesized using fault models. A number of four simulation cases were considered which take into account the normal operation of the photovoltaic panels, their malfunction due to a failure (two different types of failures were considered), and the malfunction of the panels due to the appearance of the two types of failures simultaneously, using input data that was partially measured and partially generated in Matlab. The outputs of these model simulations will be used for training the ML model
On Self-Motions of Planar Stewart-Gough Platforms
Get PDFGiven five pairs of attachment points of a planar platform, there exists a sixth point pair so that the resulting planar architecturally singular platform has the same solution for the direct kinematics. This is a consequence of the Prix Vaillant problem posed in 1904 by the French Academy of Science. The theorem discusses the displacements of certain or all points of a rigid body that move on spherical paths. Borel and Bricard awarded the prizes for two papers in this regard, but they did not solve the problem completely. In this paper, the theorem is extended to the elliptic paths in order to determine the displacements of certain or all points of a rigid body that move on super-ellipsoid surfaces. The poof is based on the trajectories of moving points which are intersections of two implicit super-ellipsoid surfaces
Investigation of the Effect of External Local Sealing Loads on the Well Support
Get PDFThe article presents the definition of problems in the well support from external local sealing loads. The conditions of local sealing loads are identified. The calculations were carried out according to the equations. A model of the stress-strain state in the well support has been created. The parameters of the effect of compression on the absolute value of strength are determined
Study on Composite Design Suitable for High Hardness and Strong Abrasive Formation
Get PDFPDC (Polycrystalline Diamond Compact bit) composite is the most important cutting element of petroleum bit, which performance directly affects the service effect and service life of the bit. During the drilling process, the cutter will produce a large amount of friction heat when cutting the rock, resulting in a sharp increase in the internal temperature of the cutter. When the temperature reaches a certain value, thermal wear and tear are very easy to occur, which will not only cause diamond delamination but also reduce the wear resistance of the cutter. Under the action of impact load, impact failure is more likely to occur, which greatly reduces the service life of the cutter and the rock-breaking efficiency of the drill bit. Therefore, this paper studies the composite interface suitable for high-temperature drilling through the changes of cutting tooth temperature field and stress field with different interface shapes, which shows that the non-planar interface is more suitable for improving the cutting tooth life of composite under the action of comprehensive stress field
Assessing the Economic Feasibility of Integrated Waste to Use Systems for Uganda
Get PDFWaste and sanitation Management is a major challenge in urban areas in Uganda where waste is composed of atleast 70% organic content and is basically collected and disposed of in landfills. While 90% of the sanitation facilities used are onsite systems often requiring additional treatment of sewage and faecal matter sewage yet faecal and sewage sludge treatment plants are few. The projected population increase is expected to further influence urbanization, increasing the need for basic waste and sanitation services. Integrated Waste to Use systems that consider combined management of organic waste streams i.e. biowaste, animal waste, sewage and faecal sludge, could be a viable solution for the urban areas. The systems which consist of a combination of anaerobic digestion, composting, incineration and solar drying technologies promote resource recovery in the form of biogas, briquettes and organic fertilizer. The economic feasibility of the Waste to Use systems was carried out and the results indicated that the feasibility of the systems was positively influenced by the inclusion of the anaerobic digestion process, which allowed for recovery of biogas and digestate as organic fertilizer. Furthermore, a combination of low system investment costs, increased revenues from resource recovery, consideration of equity capital of at least 30%, interest rate of at most 10% and fugitive emissions less than 7 % would positively influence the economic feasibility of the system alternatives
Towards Computational CO2 Capture and Storage Models: A Review
Get PDFThis review is aimed to increase knowledge on computational CO2 capture and storage models that are gradually evolving in the design and development to act as more effective carbon capture agents with acceptable toxicity and costs and complementary adjuncts to experiments for comprehending amino-CO2 reaction mechanisms. Also, the review discussed experimental research of degradation reactions of aqueous organic amines, measurements, kinetics and forecasts of amine pKₐ values and amine-CO2 equilibria. Also, the researcher comprehensively discussed the computational simulation of mechanisms of carbon capture reactions. In the contexts of experimental and computational studies, the comparative advantages of bicarbonate, carbamic acid, termolecular and zwitterion are described. Computational approaches shall gradually evolve in the design and development to act as more effective carbon capture agents with acceptable toxicity and costs and complementary adjuncts to experiments for comprehending amino-CO2 reaction mechanisms. Some of the main research findings indicate that advancements in quantum computing might help in simulating larger complex molecules such as CO2. Moreover, the simulations might discover new catalysts for CO2 capture that are more efficient and cheaper than present models. CO2 capture and storage (CCS) could minimize the CO2 emission volume by 14%. The first stride in CCS is capturing CO2. It accounts for 70% -80% of this technology total costs. Virtually, 50% of the costs to operate the post-combustion capture (PCC) plants are related to steam costs. It is thus important to acquire the best possible data to avoid unnecessary costs and overdesigns