FORMATIONAL WATER CHARACTERISTICS AS AN INDICATOR FOR THE PROCESS OF OIL MIGRATION AND ACCUMULATION AT THE AIN ZALAH FIELD, NORTHERN IRAQ

Formational water characterization denotes a chloride-calcium type in the S₁S₂A₂ class. It indicates a hydrodynamic zone unfavourable for hydrocarbon preservation in the eastern block of the field. These waters have an index of base exchange (IBE) greater than 0.129, indicating connate oil reservoir waters, migrating with oil from the oil source-beds at the southern parts of the field through connected openings and fault planes.
The entrapment of oil took place at the crestal parts of the folded structure to the west and NW of the field. The water moved down-dip along the eastern flank, creating capillary pressure, forcing the oil to accumulate in subcapillary pores at the top-most parts of the upper pay-zone. The latter section became oil-wet. The oil wettability led to entrapment of a quantity of oil in the subcapillary pores that was then left behind during oil production operations, necessitating secondary recovery methods.
The occurrence of more lighter constituents in crudes of the upper pay-zone than in the lower one is due to fractionation and differentiation during migration.     

On the Applicability of Gardon's Equations for the Calculation of Particle Size in Emulsion Polymerisation

Gardon's revision of the Smith-Ewart theory of emulsion polymerisation makes it possible to calculate the average particle size of the latex produced from the conditions used for the polymerisation at least for monomers with a low monomer transfer constant. Good agreement has been found between the calculated particle sizes and the turbidity averages measured by light scattering for polystyrene latices prepared with various emulsifiers. However the theory neglects the effect of the ionic strength of the aqueous phase although Gardon's own results show this to be a significant parameter: increase of ionic strength increases the average size of the latex particles by reducing electrostatic stabilisation. The difference between the total and the micellar surfactant concentration is significant for surfactants with relatively high critical micelle concentrations and a considerable improvement in agreement between measured and calculated particle sizes is found when the concentration of micellar surfactant is used in the calculation. The theory requires the reaction rate to depend on the 3/5ths power of the concentration of micellar surfactant and although this would appear to have been satisfactorily verified experimentally, replotting of the extensive series of precise results published by Bartholome, Gerrens, Herbeck and Weitz shows that the double logarithmic plot is not actually linear. This is probably the result of a slow change of micelle size as the surfactant concentration is increased.     

Supporting top-<Emphasis Type="Italic">k</Emphasis><Emphasis Type="Italic">join</Emphasis> queries in relational databases

Ranking queries, also known as top-k queries, produce results that are ordered on some computed score. Typically, these queries involve joins, where users are usually interested only in the top-k join results. Top-k queries are dominant in many emerging applications, e.g., multimedia retrieval by content, Web databases, data mining, middlewares, and most information retrieval applications. Current relational query processors do not handle ranking queries efficiently, especially when joins are involved. In this paper, we address supporting top-k join queries in relational query processors. We introduce a new rank-join algorithm that makes use of the individual orders of its inputs to produce join results ordered on a user-specified scoring function. The idea is to rank the join results progressively during the join operation. We introduce two physical query operators based on variants of ripple join that implement the rank-join algorithm. The operators are nonblocking and can be integrated into pipelined execution plans. We also propose an efficient heuristic designed to optimize a top-k join query by choosing the best join order. We address several practical issues and optimization heuristics to integrate the new join operators in practical query processors. We implement the new operators inside a prototype database engine based on PREDATOR. The experimental evaluation of our approach compares recent algorithms for joining ranked inputs and shows superior performance.Received: 23 December 2003, Accepted: 31 March 2004, Published online: 12 August 2004Edited by: S. AbiteboulExtended version of the paper published in the Proceedings of the 29th International Conference on Very Large Databases, VLDB 2003, Berlin, Germany, pp 754-765     

The recent air temperature rise in Kuwait

Recently, there is increasing concern in Kuwait regarding the frequent occurrences of harsh climate conditions with summer air temperature exceeding the 50°C mark. In particular, in the last 20 years, the maximum yearly temperature is persistently exceeding its mean value for the whole recorded period.In an effort to explain this phenomenon, a study was made on the surface air temperature records for the past three decades measured at Kuwait International Airport and at a nearby coastal station at Ras Al-Khafja. The analyses have demonstrated that the airport weather station is more influenced by urbanization than Ras Al-Khafja.The linear trend of the air temperature data for both stations consistently showed a cooling period until 1972, followed by a warming period with temperature increases in the range of 0.03–0.08°C yr⁻¹. This warming trend is believed to be partly due to global climate change and the rest is due to man-induced local change in climate caused by urbanization. The urban warming appears to be both a daytime and night-time phenomenon, with maximum, mean and minimum temperatures showing a considerable increase. It is estimated that urban warming accounts for 25% of the maximum temperature increase.     

Distributed Coalition Formation Games for Secure Wireless Transmission

Cooperation among wireless nodes has been recently proposed for improving the physical layer (PHY) security of wireless transmission in the presence of multiple eavesdroppers. While existing PHY security literature answered the question “what are the link-level secrecy rate gains from cooperation?”, this paper attempts to answer the question of “how to achieve those gains in a practical decentralized wireless network and in the presence of a cost for information exchange?”. For this purpose, we model the PHY security cooperation problem as a coalitional game with non-transferable utility and propose a distributed algorithm for coalition formation. Using the proposed algorithm, the wireless users can cooperate and self-organize into disjoint independent coalitions, while maximizing their secrecy rate taking into account the costs during information exchange. We analyze the resulting coalitional structures for both decode-and-forward and amplify-and-forward cooperation and study how the users can adapt the network topology to environmental changes such as mobility. Through simulations, we assess the performance of the proposed algorithm and show that, by coalition formation using decode-and-forward, the average secrecy rate per user is increased of up to 25.3 and 24.4% (for a network with 45 users) relative to the non-cooperative and amplify-and-forward cases, respectively.     

An assessment of the kernel‐distance‐based multivariate control chart through an industrial application

Traditional multivariate quality control charts assume that quality characteristics follow a multivariate normal distribution. However, in many industrial applications the process distribution is not known, implying the need to construct a flexible control chart appropriate for real applications. A promising approach is to use support vector machines in statistical process control. This paper focuses on the application of the ‘kernel‐distance‐based multivariate control chart’, also known as the ‘k‐chart’, to a real industrial process, and its assessment by comparing it to Hotelling's T² control chart, based on the number of out‐of‐control observations and on the Average Run Length. The industrial application showed that the k‐chart is sensitive to small shifts in mean vector and outperforms the T² control chart in terms of Average Run Length. Copyright © 2010 John Wiley & Sons, Ltd.     

Silicon Seed Priming Enhances Salt Tolerance of Barley Seedlings through Early ROS Detoxification and Stimulation of Antioxidant Defence

Silicon - Seed priming has recently gained considerable attention to induce salt tolerance in several crop plants. In the present study, we evaluated the effect of seed priming with silicon (Si)...     

High reliability of real-time visual data transmission using superposition coding with receiver diversity

Supporting visual data applications in the real-time communication systems are among the most challenging issues over the next generation wireless communication systems. This challenge is further magnified by the fact that the quality of reception is highly sensitive to transmission delay, data losses and bit error rate (BER) in such applications. In this paper, we proposed Superposition Coding with Receiver Diversity (SPC-RD) scheme, which employs unequal error protection (UEP) to improve the error performance, maximize the received signal to noise ratio (SNR) and optimize the reliability of the transmission system. In the transmitter side, the visual data is divided into a number of different priority layers based on their effects on the reception quality. These layers are modulated individually where the highest priority layer is modulated with the highest UEP level against error-prone channels, and vice versa. These modulated signals are then superimposed together and transmitted via wireless Single-Input Multiple-Output (SIMO) Rayleigh fading channel. In the receiver side, three different diversity combining approaches; selection combining (SC), equal gain combining (EGC) and maximal ratio combining (MRC) are considered. The combined signal is then passed through a multiuser demodulator so-called the ordered successive interference cancellation (O-SIC) demodulator to reconstruct and separate the data layers. This demodulation technique is evaluated and compared with the traditionally maximum likelihood joint detection (MLJD) technique. Extensive simulations have been carried out to validate the various assertions. Under the assumption of equal transmission power, the simulation results illustrate that the proposed SPC-RD scheme provides a SNR gain of 14.5 dB over the Rayleigh fading channel at the diversity order of three for the acceptable BER level of 10^?3 when BPSK scheme is exploited compared to the traditional equal error protection system. In addition, the proposed scheme with O-SIC demodulation technique achieves almost similar performance compared to MLJD technique but using less computational complexity.     

Time-to-Pinch Investigation of 5 kJ Mather-Type Plasma Focus Device

The Egyptian Atomic Energy Authority-Plasma focus (EAEA-PF2) has been upgraded to a 5 kJ plasma focus device. Its characteristics have been investigated at various pressures and different voltages in a 5 kJ Mather-type plasma focus device for Ar gas. Its time-to-pinch has been measured, simulated and analyzed at different operating conditions. It is observed from the results that, the time-to-pinch decreased when either the charging voltage increased or the gas pressure decreased. In addition, the time-to-pinch is estimated theoretically using Lee model RADPF5.15. A comparison between the experimental and theoretical time-to-pinch is discussed. Also, the drive factor of plasma focus is analyzed at different pressures and charging voltages. It is noticed that, the mass and current factors are affected by changing the pressure and voltage. Finally, it is observed that, the drive factor is proportional inversely to the pressure and directly to the charging voltage.     

Comparative study of various methods for extraction of multi- quantum wells Schottky diode parameters

In this work, forward current voltage characteristics for multi-quantum wells Al_0.33Ga_0.67As Schottky diode were measured at temperature ranges from 100 to 300 K. The main parameters of this Schottky diode, such as the ideality factor, barrier height, series resistance and saturation current, have been extracted using both analytical and heuristics methods. Differential evolution (DE), particle swarm optimization (PSO) and artificial bee colony (ABC) have been chosen as candidate heuristics algorithms, while Cheung technic was selected as analytical extraction method. The obtained results show clearly the high performance of DE algorithms in terms of parameters accuracy, convergence speed and robustness.