3,236 research outputs found
Spin Zero Quantum Relativistic Particles in Einstein Universe
In this letter we have considered the eigenvalues and eigenfunctions of
relativistic massless scalar particle which conformally coupled to the
background of Einstein universe. We found the eigenvalues and eigenfunctions
exactly.Comment: 4 pages, no figure, accepted for publication in International Journal
of Theoretical Physic
On the Integration of Emerging Stock Markets in the Middle East
Results from the Johansen-Juselius test suggest that the Middle East emerging stock markets are segmented globally, but appear highly integrated within the region. Moreover, the Gonzalo- Granger test, in conjunction with error-correction models, indicates that the market in Egypt is a dominant force driving other markets in the region. The apparent segmentation of the markets in the Middle East from the global market implies that these emerging markets provide international investors with potential diversification gains.
Bridging Serious Games and Participatory Design
Participatory design (PD) has become widely popular within the interaction design community, but to date has had little influence within serious game design processes. We argue that serious game design complicates the notion of involving users as co-designers, as serious game designers must be fluent with both domain content and game design. In this paper, we share our experiences of using PD during the design process of a serious game. We present observations stemming from attempts to apply the existing PD methods of brainstorming and storyboarding. Reflecting on the shortcomings of these methods, we go on to propose a novel PD method that leverages two fundamental qualities of serious games–domain expertise and procedurality–to scaffold players’ existing knowledge and make co-design of serious games an attainable goal
Analysis of Heat Transfers inside Counterflow Plate Heat Exchanger Augmented by an Auxiliary Fluid Flow
Enhancement of heat transfers in counterflow plate heat exchanger due to presence of an intermediate auxiliary fluid flow is investigated. The intermediate auxiliary channel is supported by transverse conducting pins. The momentum and energy equations for the primary fluids are solved numerically and validated against a derived approximate analytical solution. A parametric study including the effect of the various plate heat exchanger, and auxiliary channel dimensionless parameters is conducted. Different enhancement performance indicators are computed. The various trends of parameters that can better enhance heat transfer rates above those for the conventional plate heat exchanger are identified. Large enhancement factors are obtained under fully developed flow conditions. The maximum enhancement factors can be increased by above 8.0- and 5.0-fold for the step and exponential distributions of the pins, respectively. Finally, counterflow plate heat exchangers with auxiliary fluid flows are recommended over the typical ones if these flows can be provided with the least cost
Mathematical and Numerical Analysis of Heat Transfer Enhancement by Distribution of Suction Flows inside Permeable Tubes
Heat transfer enhancement in permeable tubes subjected to transverse suction flow is investigated in this work. Both momentum and energy equations are solved analytically and numerically. Both solutions based on negligible entry regions are well matched. Two different suction velocity distributions are considered. A parametric study including the influence of the average suction velocity and the suction velocity profile is conducted for various Peclet numbers. It is found that enhancement of heat transfer over that in impermeable tubes is only possible with large Peclet numbers. This enhancement increases as suction velocities towards the tube outlet increase and as those towards the tube inlet decrease simultaneously. The identified enhancement mechanisms are expanding the entry regions, increasing the transverse advection, and increasing the downstream excess temperatures under same transverse advection. The average suction velocity that produces maximum enhancement increases as the Peclet number increases until it reaches asymptotically its uppermost value at large Peclet numbers. The maximum reported enhancement ratios for the exponential and linear suction velocity distributions are 17.62-fold and 14.67-fold above those for impermeable tubes, respectively. This work demonstrates that significant heat transfer enhancement is attainable when the suction flow inside the permeable tubes is distributed properly
Process analysis and improvement of a Claus unit of an existing gas plant
This research is a part of Master degree research programme at Cranfield University
to study Claus process and perform process analysis on an existing Sulphur recovery
unit in a gas plant.
The Mellitah Plant, in Western Libya, is a gas plant designed to treat raw gas and
condensate from offshore gas fields in several processing units where the sour gas
(H2S, CO2, COS, SC2) is removed to meet the international emission standard, in order
to control the emission and pollution from the flue gas. The acid gases are treated in
Claus unit where H2S is converted to sulphur in multi-reaction steps. These reactions
start in a combustion reaction zone, thermal reactor, to produce a suitable mixture of
H2S to SO2. The mixture reacts in Claus catalytic reactors to produce sulphur vapour.
The sulphur vapour is condensed in multi-condensing steps after each catalytic
reactor.
The ultimate aim of this research is to carry out the process analysis for Claus unit in
order to recover the waste energy to increase the plant productivity, minimise the use
of the plant utilities, and decrease the environmental pollution. A process model of the
plant was developed and validated in Aspen HYSYS. The process was then analysed,
the analysis has resulted in a significant increase in Claus unit overall conversion ratio
which has increased from 61% to 97.63% H2S base. Consequently, Claus unit
productivity has increased by approximately 1.72 times. In addition, a higher amount
of energy is recovered in a form of heat by heating the boiler feed water to produce
both high pressure steam in the waste heat boiler and low pressure steam in 1st and
2nd sulphur condensers. Both high pressure and low pressure steam total production
are increased by 1.5 times. All this has been achieved at high conversion ratio number
of 2 in tail gas which represents optimum O2/H2S ratio in the thermal reactor feed and
the high conversion number can be kept in between 1.5 to 3 during plant normal
operation
Corporate Governance and Institutional Performance in Jordanian Schools with International Programs
This study aims to examine the effect of corporate governance on improving the institutional performance of Jordanian schools applying international programs. Following the descriptive analytical approach, the study sample included (66) schools applying international programs in Amman. The study used an electronic questionnaire to collect primary data from members of the administrative and teaching staff in the study sample schools, and due to the difficulty of limiting these individuals to a specific number, (500) questionnaires were distributed, to include the largest number of members of the study community. The study found that schools applying international programs in Jordan are interested in applying corporate governance to a high degree and the (strategic vision) dimension is one of the most important corporate governance dimensions. Further, there is a statistically significant effect of corporate governance in terms of its dimensions (rule of law, justice, transparency, accountability, equality, and strategic vision) in improving the institutional performance in terms of its dimensions (institutional effectiveness, efficiency, relevance, and continuity) in schools applying international programs in Jordan. The study recommends the administrations of schools applying international programs in Jordan to prepare written rules and regulations that clarify the rights, responsibilities and work procedures for all its employees at each organizational level in the school, and to apply these rules with complete transparency for everyone without any discrimination
- …