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Open access

Badreddine Meftah and Abdourazek Souahi

Abstract

In this paper we establish some fractional Hermite-Hadamard type integral inequalities for functions whose modulus of the mixed derivatives are co-ordinated s-preinvex in the second sense.

Open access

Charles C. Ekeh, Etim D. Uko, Ejiro F. Eleluwor and Friday B. Sigalo

Abstract

Geophysical well logs were used to delineate the stratigraphic units and system tracks in the XYZ Field of the Niger Delta. The gross percentages for sand levels range from 93-96% in the shallow levels to 60-66% in the deeper levels. Porosity values ranged between 27% at shallower sections and 9% at deeper depths. Six depositional sequences were identified and categorized into their associated system tracts. Porosity decreases with depth in normal compacted formation for both sandstone and shale units. Surface porosity for sandstone is 42%, and for shale it is 38.7% from extrapolation of sub-surface porosity values to the surface. The depth to the base of Benin Formation is highly variable ranging between 1300 and 2600m. This study reveals the possibility to correlate sand levels over long distances which enables inferring porosity values laterally. The knowledge of the existent stratigraphic units, the Benin, Agbada and Akata Formations and their petrophysical parameters such as porosity, lateral continuity of the sands and shales, the variation of the net-togross of sands with depth, enables the reservoir engineer to develop a plan for the number and location of the wells to be drilled into the reservoir, the rates of production that can be sustained for optimum recovery. The reservoir engineer can also estimate the productivity and ultimate recovery (reserves) using the results on this work.

Open access

Boris Reznikov, Alexander Ruderman and Valentina Galanina

Abstract

The paper considers a discrete state-space model for transients in a three-level flying capacitor DC–DC converter. A transition matrix is obtained for a pulse width modulation (PWM) period. The matrix elements are expanded into a power series using a selected small parameter. The matrix eigenvalues that determine the natural balancing dynamics transients are presented in the form of power series as well. Four separate transients are constructed based on four possible PWM period initial states (topologies). Inductor current and capacitor voltage transients are found for the voltage source power-up as the arithmetic average of the four separate transients. The discrete solutions are replaced by continuous ones. The resulting transients that are elementary functions of the circuit parameters, PWM period, and voltage reference demonstrate good agreement with the simulation results.

Open access

Tibor Vajsz, László Számel and Árpád Handler

Abstract

Motion control is facing an increasing popularity in the present research activities. Owing to the expected wide spreading of motion control applications, it can be predicted that the advancements in the field of electric motor drives will have a high level of influence on the new results in the field of motion control. The synchronous reluctance motor drives mean an excellent and yet cost-effective solution for actuators in motion control applications. In this article, the direct torque control with space vector modulation is analysed as a possible candidate for synchronous reluctance motor motion control applications. Its torque-control performance is investigated as a function of torque-control sample time, and a comparison of the torque ripples is made with other torque-control algorithms by an FFT analysis.

Open access

Marapureddy Murali Krishna Rao

Abstract

In this paper, we introduce the notion of a Г-field as a generalization of field, study them properties of a Г -field and prove that M is a Г-field if and only if M is an integral, simple and commutative Г-ring.

Open access

Andrzej G. Chmielewski and Marcin Sudlitz

Abstract

Large quantity of sewage sludge originating from wastewater treatment plants is becoming a growing problem from environmental and human health points of view. One of the ways to use sewage sludge is agricultural purpose due to its nutrients and organic matter content, but the condition is that it should be deprived of pathogenic bacteria and parasite egg contamination. Application of ionizing radiation to hygienize sewage sludge can make it appropriate for agricultural use. The process does not require addition of chemicals to sludge; it is environmentally friendly and effective in removal of biological threats. In the past, successful attempts of sewage sludge treatment using ionizing radiation were made. Pilot plants and commercial ones proved that pathogens can be easily removed from sewage sludge by ionizing radiation. The concept of ‘zero energy’ biogas plant is based on the construction of a complex system consisting of biogas plant and electron accelerator in the biofertilizer manufacturing line. Digestate originating from the methane fermentation of sewage sludge is irradiated to remove all pathogens using electron beam from an accelerator powered by electric energy obtained from burning biogas in a cogenerator. The product is a high-quality, biologically safe fertilizer.

Open access

R. Scott Kretchmar

Abstract

Loy and Morford focus on “agon” as an important window through which to understand human life and development. Competition in war and sport was culturally significant then, and it is culturally significant today, albeit in modified forms. In this commentary, I attempt to do two things – first, identify implications of some conceptual distinctions, and second, point out normative questions raised by the Loy/Morford analysis. I find it worthwhile to differentiate clearly between tests and contests. If the historical and sociocultural spotlight were turned on sporting “tests” rather than “contests”, that is, on trying to solve physically demanding problems well rather than trying to solve them better than at least one other party, then another story than the agonal account could be told. War would probably no longer serve as the best historical and prehistorical analogue for sport. Rather, it might be hunting. I add, that, on one hand, competitive sport is far less violent and, therefore, far more defensible today than it was previously. On the other hand, joy in playing is often sacrificed on the altar of any number of extrinsic rewards. Success, even gained by questionable means, replaces skill-based and virtue-generated achievement. This threatens the connection endorsed by MacIntyre between practices and virtues.

Open access

Dorin Sarafoleanu and Raluca Enache

Abstract

Whiplash syndrome is a quite common pathology and can be defined as a neck injury produced by a sudden acceleration-deceleration, the consequence of which is a sudden forward and backward movement of the head and neck. The main production mechanism is a sudden acceleration-deceleration process that has as a consequence the sudden extension/flexion of the neck. Starting from the many structures involved, the whiplash syndrome is an interdisciplinary challenge (ENT specialist, neurologist, orthopedist, ophthalmologist, psychologist) and can be described by multiple signs and symptoms.

Whiplash syndrome is a complex pathology both through the mechanism of production and symptoms, and through the forensic implications that it has. The interdisciplinary medical collaboration, the implementation of stricter rules on wearing the seat belt and the development by car manufacturers of chairs and head restraints that protect the head and neck of passengers, would be the preventive step in the occurrence and especially the chronicization of these lesions.