Development of shrouded turbojet to form a turboramjet for future missile applications

Development of shroud to form part of an afterburner for a turbo- ramjet engine which has a possible application for high speed long range missile applications. Research has been conducted on scram-jet engines with little or no emphasis on a turbojet/ramjet combined cycle engines. With the possibility of the turbojet providing the thrust at subsonic conditions and the ramjet providing the thrust at supersonic conditions. A small turbojet engine, the Sophia J450 was evaluated experimentally and the results were compared to the prediction using an industry standard program with a perfect comparison over a wide operating range. In order to study possible turbo-ramjet configurations, a Sophia J450 turbojet engine was used with varying shroud configurations, to compare static thrust and specific fuel consumption measured in a test rig. Shroud pressures were also recorded to determine the entrainment rate of the ducts. The short shroud results were found to produce the best performance of the three configurations tested, which were more significant at lower engine spool speed that produced a sharp increase in secondary entrainment pressure. A conical supersonic intake was designed for combined cycle engine at a Mach 2 flight condition resulting in a near optimum cone angle of 15 (deg) to be tested in the new free jet facility. The flight envelope of the baseline engine was also determined over a wide range of flight speeds and operating altitudes.http://www.archive.org/details/developmentofshr00alnaCaptain, Royal Army of OmanApproved for public release; distribution is unlimited

Investigation of Water-Coning Phenomenon in Iranian Carbonate Fractured Reservoirs

Abstract The water coning caused by the imbalance between gravity and viscous forces is the most important reason for water production in different fractured reservoirs. There are various controllable and uncontrollable parameters affecting this phenomenon. In this study different dynamic models were constructed to search for the key parameters affecting the coning process in both single-well and Cartesian multi-well models. It has been determined that oil layer thickness, perforation thickness, fracture permeability and its orientation, especially horizontal not vertical fracture permeability, production rate, mobility ratio, and fracture storativity have the major role in water coning phenomenon. Also it has been determined that fracture spacing, aquifer strength and skin factor have insignificant effect on water coning in fractured reservoirs. The variation of water breakthrough time respect to each effective parameter has also been studied. We concluded that for any production program or adjusting the wells location, the parameter study is very important. Multi-well studies using an Iranian fractured reservoir data show that the trend of dependency of water coning on each parameter is similar to the single-well model. However, in field scale, it is necessary to have all reservoir data including well location, and production history for a successful water coning simulation because a small pressure drawdown exerted by a far well will affect the cone shape and its breakthrough time. Introduction The production of water from oil producing wells is a common occurrence in oilfields. It may be attributed to one or more reasons such as normal rise of oil water contact, water coning, and/or water fingering. The water production increases the operating cost and it may also reduce both reserve and recovery.1 Among these mechanisms, water coning is a serious problem in many oilfields especially in some large Middle East oil reservoirs, where the oil zone has an aquifer underneath whether or not it serves as an active drive.2 Water coning is caused by an imbalance between the gravitational and viscous forces around the completion interval 1. In other words the flow of oil from the reservoir to the well introduces an upward dynamic force upon the reservoir fluids. This dynamic force due to wellbore drawdown causes the water at the bottom of the oil layer to rise to a certain point at which the dynamic force is balanced by the height of water beneath that point (Figure 1). Now, as the lateral distance from the wellbore increases, the pressure drawdown and the upward dynamic force decrease. Thus, the height of the balance point decreases as the distance from the wellbore increases. Therefore, the locus of the balance point is a stable cone shaped water-oil interface. At this stable situation oil flows above the interface while water remains stationary below the interface. 3 The extent of cone growth and/or its stabilization in conventional reservoirs depend on different factors such as mobility ratio, oil zone thickness, the extent of the well penetration, and vertical permeability; but the most important parameter is total production rate. 2 In case of fractured reservoir this problem is more complicated because a dual porosity system results in formation of two cones. Depending on the rates, it may be developed a fast moving cone in the fracture and a slow moving one in the matrix. The relative position of the two cones is rate sensitive and is a function of reservoir properties.4 While there are many theoretical works in the case of conventional reservoirs 5, only limited analytical works are available for the ideal cases of fractured reservoirs such as Birks theory. 6, 7 In fractured reservoirs, critical rate are influenced by extra factors such as fracture storativity w, fracture transmissivity l, fractures pattern and their interaction to matrixes especially around the wellbore. Shorter breakthrough times and lower critical rates are predicted for fractured systems.4 In this study some simulation models have been constructed to analyze the effect of different parameters on water coning in single-well models (Figure 2). Furthermore some models have been constructed to analyze the coning phenomenon in multi-well configuration (Figure 3). M. Namani and M. Asadollahi, and M. Haghigh

Investigation of Cementation Factor in Iranian Carbonate Reservoirs

Cementation factor (cementation exponent) is one of the most important parameters in saturation equation to determine the water or hydrocarbon saturations. It acts as a power of porosity in the most of saturation equations which increases the importance of this parameter. The best cementation factor data is based on laboratory measurements and log interpretation results, but sometimes it is considered as a constant value in oil and gas reservoirs which causes large errors in saturation calculations. Using a constant value for cementation factor in saturation equations may cause large errors and uncertainties in hydrocarbon saturation determination because it is dependent to porosity value, type of porosity and pore types, pressure and lithology. Correlations are the best alternatives when there are not sufficient laboratory measurements or accurate log interpretation values. The effect of cementation factor on saturation was investigated. It was shown that cementation factor has almost the same values in porosities more than 5 percent but there are completely different values in porosities less than 5 percent. Investigation of pressure, porosity and lithology effects on cementation factor from the laboratory measurements and log interpretation in Iranian carbonate reservoirs was resulted in a new correlation for Sarvak, Kangan and Dalan formations. In the new correlation, cementation factor was plotted versus porosity to compare with the most famous existing correlations like Shell and Borai. The most common correlation which is being used in Iranian reservoirs is Shell formula whereas it has completely different trend compared to the new correlation in low porosities. Also a couple of Monte Carlo simulations were used to investigate the effect of cementation factor on water saturation uncertainty in an Iranian carbonate reservoir. The first Monte Carlo simulation was done based on the existing laboratory and log data and the second one based on the new correlation for cementation factor. Results showed that application of appropriate correlations was resulted in decreasing saturation uncertainty. The accurate determination of cementation factor improves the saturation determination and consequently OOIP calculations. Also, applying the correlations decreases the uncertainty of saturations in the reservoir zones to increase the accuracy level of possible, probable and proven reserves in a hydrocarbon reservoir.Masoud Asadollahi, Ali Mohammad Bagheri, Manouchehr Haghighi, Mehran Naman

Role of Coronary Myogenic Response in Pressure-Flow Autoregulation in Swine: A Meta-Analysis With Coronary Flow Modeling

Myogenic responses (pressure-dependent contractions) of coronary arterioles play a role in autoregulation (relatively constant flow vs. pressure). Publications on myogenic reactivity in swine coronaries vary in caliber, analysis, and degree of responsiveness. Further, data on myogenic responses and autoregulation in swine have not been completely compiled, compared, and modeled. Thus, it has been difficult to understand these physiological phenomena. Our purpose was to: (a) analyze myogenic data with standard criteria; (b) assign results to diameter categories defined by morphometry; and (c) use our novel multiscale flow model to determine the extent to which ex vivo myogenic reactivity can explain autoregulation in vivo. When myogenic responses from the literature are an input for our model, the predicted coronary autoregulation approaches in vivo observations. More complete and appropriate data are now available to investigate the regulation of coronary blood flow in swine, a highly relevant model for human physiology and disease

Local E-Government Impact in China, New Zealand, Oman, and the United Kingdom

Purpose - To provide a picture of (local) e-government impact and development philosophy in China, New Zealand, Oman, and the United Kingdom. Design/methodology/approach - A survey instrument was used to collect data from policymakers in 114 civil service organisations in four countries during 2007. Findings - Policymakers in every country reported only low-medium levels of agreement that their e-government initiatives had yielded significant benefits for organisations and citizens alike over, a broad range of performance measures concerning service quality, citizen satisfaction, productivity, and management effectiveness. In interactions with stakeholders that are both directive and maintain control over citizens, policymakers also favour the provision of online services that offer ever increasing amounts of information, rather than collaborative service channels that engage citizens in local decision-making. Research limitations/implications - Less than a 100 percent response rate gave an incomplete snapshot of the e-government scene in the four countries studied. Also, a lack of understanding of some key e-government issues plus cultural response bias may have led to erroneous/biased responses. Practical implications - In an era in which public sector organisations worldwide are under pressure to demonstrate success in service delivery and organisational performance, policymakers do not perceive online services as an opportunity to reduce the costs of physical infrastructure or to improve democracy via shared decision making. Thus further erosions of trust and participation in democracy may continue unless citizens are given similar choices in the democratic system to those they have in their everyday lives. Originality/value - This research was undertaken at the local level of government and in a diverse range of countries where the political, social, economic, and cultural environments can differ markedly. It evaluates the significance of key e-government issues in Western, Arabic, and Eastern contexts, enabling international comparisons to be made across these cultural settings. Impacts of the e-government initiatives on organisations and citizens are presented and compared; and policymaker attitudes to new technology having the potential to enhance the democratic process are presented

Efficient Desalination of Brackish Ground Water via a Novel Capacitive Deionization Cell Using Nanoporous Activated Carbon Cloth Electrodes

Sea water intrusion in ground water sources has made brackish water desalination a necessity in Oman. The application of capacitive deionization (CDI) for the deionization of ground water samples from wells in Al-Musanaah Wilayat is proposed and demonstrated. A CDI cell is fabricated using nanoporous activated carbon cloth (ACC) as the electrodes and is shown to be power efficient for desalting ground water samples with total dissolved solids (TDS) of up to 4,000 mg/l. The CDI cell was able to remove up to 73% of the ionic scaling and fouling contaminants from brackish water samples. The power consumption for deionization of brackish water was estimated to be 1 kWh/m3 of desalinated water, which is much lower than the power required to process water with equivalent TDS by the reverse osmosis processes. The CDI process is elaborated, and observations and analysis of the ion adsorption characteristics and electrical properties of the capacitive cell are elucidated

Potential of using groceries in disasters/pandemics management: case of Al Ain City, UAE

AbstractScopus database between 2000 and 2023 showed that while groceries are vital in disaster/pandemic management, their roles have not been adequately addressed in the literature. In this study, we argued that privately owned groceries can complement large food storage facilities and provide effective and sustainable Public–Private Partnerships-PPP for disaster/pandemic management. We supported our argument with surveys of 254 customers and 100 grocery tenants, as well as a spatial analysis utilizing Geographic Information Systems (GIS). The results indicated that 62% of customers and 89% of grocery tenants agreed that grocery sales increased during COVID-19. Furthermore, 75% of customers agreed that groceries are vital during disaster/pandemic, and 81.8% of grocery tenants agreed that their current infrastructure allows their stores to become emergency food depots. Through GIS analysis, we found that groceries are clustered around population centers, and 69% of customers have groceries within a 5–10-minute walking distance. Our results demonstrated that groceries can be crucial in disaster management. The study aligns with the Sendai Framework for Disaster Risk Reduction 2015–2030 and UN-SDG goals 11 and 17. The findings could be utilized by organizations working in the field of disaster/pandemic management. The research fills a gap in the literature and offers new insights into the potential of using privately owned groceries in disaster/pandemic management. It highlights the need for further consideration of these important community resources

Potential of using groceries in disasters/pandemics management: case of Al Ain City, UAE

Scopus database between 2000 and 2023 showed that while groceries are vital in disaster/pandemic management, their roles have not been adequately addressed in the literature. In this study, we argued that privately owned groceries can complement large food storage facilities and provide effective and sustainable Public–Private Partnerships-PPP for disaster/pandemic management. We supported our argument with surveys of 254 customers and 100 grocery tenants, as well as a spatial analysis utilizing Geographic Information Systems (GIS). The results indicated that 62% of customers and 89% of grocery tenants agreed that grocery sales increased during COVID-19. Furthermore, 75% of customers agreed that groceries are vital during disaster/pandemic, and 81.8% of grocery tenants agreed that their current infrastructure allows their stores to become emergency food depots. Through GIS analysis, we found that groceries are clustered around population centers, and 69% of customers have groceries within a 5–10-minute walking distance. Our results demonstrated that groceries can be crucial in disaster management. The study aligns with the Sendai Framework for Disaster Risk Reduction 2015–2030 and UN-SDG goals 11 and 17. The findings could be utilized by organizations working in the field of disaster/pandemic management. The research fills a gap in the literature and offers new insights into the potential of using privately owned groceries in disaster/pandemic management. It highlights the need for further consideration of these important community resources. There are many lessons learned from COVID-19 pandemic. For example, the need for decentralization of food stores and cooperation between public and private sectors (Public–Private Partnerships-PPP). This study provides insights on how privately owned groceries can complement large food storage facilities and provide sustainable PPP. Feedback from grocery tenants and customers showed that groceries can be crucial in disaster management. The grocery sector could bring innovative solutions to food distribution during a disaster/pandemic. Integration of Geographic Information Systems (GIS) is found crucial in supporting surveys. PPP can save time, save cost, improve efficiency, and bring various benefits to stakeholders involve in disaster management.</p