Space-Time Structure and Electromagnetism

Two Lagrangian functions are used to construct geometric field theories. One of these Lagrangians depends on the curvature of space, while the other depends on curvature and torsion. It is shown that the theory constructed from the first Lagrangian gives rise to pure gravity, while the theory constructed using the second Lagrangian gives rise to both gravity and electromagnetism. The two theories are constructed in a version of absolute parallelism geometry in which both curvature and torsion are, simultaneously, non-vanishing. One single geometric object, {\it W-tensor}, reflecting the properties of curvature and torsion, is defined in this version and is used to construct the second theory. The main conclusion is that a necessary condition for geometric representation of electromagnetism is the presence of a non-vanishing torsion in the geometry used.Comment: 17 pages, LaTeX file, revised versio

Cohomology of osp(1∣2)\frak {osp}(1|2) acting on the space of bilinear differential operators on the superspace R1∣1\mathbb{R}^{1|1}

We compute the first cohomology of the ortosymplectic Lie superalgebra $\mathfrak{osp}(1|2)$ on the (1,1)-dimensional real superspace with coefficients in the superspace $\frak{D}_{\lambda,\nu;\mu}$ of bilinear differential operators acting on weighted densities. This work is the simplest superization of a result by Bouarroudj [Cohomology of the vector fields Lie algebras on $\mathbb{R}\mathbb{P}^1$ acting on bilinear differential operators, International Journal of Geometric Methods in Modern Physics (2005), {\bf 2}; N 1, 23-40]

Change in antioxidant and lignifying enzyme activities in rubbing tomato (Solanum lycopersicum) internodes

In tomato plant, rubbing applied to a young internode inhibits elongation of the rubbed internode and its neighbouring one. These morphological changes were correlated with an increase in lignification enzyme activities, phenylalanine ammonia-lyase (PAL) and peroxidases (POD), 24 h after rubbing of theforth internode. Furthermore, a decrease in indole-3-acetic acid (IAA) content was detected in the rubbed internode and the upper one. Lignin synthesis in tomato plant measured 14 days after mechanical stress application was significantly stimulated in the rubbed internodes (n°4) as compared with the control. Fourier transform infrared (FTIR) analyses revealed that lignin synthesized in response to mechanical elicitation displayed a distinct structure, substantially enriched in syringyl (S) units, as compared to constitutive lignin. Taken together, our results suggest that the decrease in rubbed internode length is as a result of IAA oxidation, increases in enzyme activities (PAL and POD) and cell wall rigidification induced by lignification process.Key words: Mechanical stimulation, Solanum lycopersicum, indole-3-acetic acid (IAA), Fourier transform infrared (FTIR), lignin

Multi-Channel Preemptive Priority Model for Spectrum Mobility in Cognitive Radio Networks

Cognitive Radio techniques have been proposed for improving utilization of the spectrum by exploiting the unoccupied bands of the licensed spectrum. This paper proposes a preemptive multi-channel access model for prioritized cognitive radio networks using an iterative method of queuing theory to solve the spectrum scarcity problem. The proposed model formulates accurate closed form of an expected waiting time in the queue, an expected number of users in the queue, an expected waiting time in the system, and an expected number of users in the system. The results compared to the basic model (without preemptive priority) show that, the waiting time in queue and the waiting time in the system compared to the basic model will be improved by 92.99% and 33.15% respectively for class one secondary user. The results also show that, the waiting time in queue and the waiting time in the system will be improved by 43.25% and 15.42% respectively for class two secondary users. The proposed model investigates the desirable schedules of primary and secondary users

The conception of the aggregator in demand side management for domestic consumers

In the demand side management (DSM) the aggregator is appearing as a key player in managing the demand during the peak hours by acting as an energy manager between the utility and the consumer. In this work, an emerging concept of the energy service provider as a business entity for domestic consumers is discussed and focuses on the interactional issues between the utility, the aggregator and the consumers. The paper also discusses the role of communication in the interaction among the three players

Effects of Vibration Located on the Steel Truss Bridges Under Moving Load

Structural vibration control as an advanced technology in engineering consists of implementing energy dissipation devices or control systems into structures to reduce excessive structural vibration, enhance human comfort and prevent catastrophic structural failure due to strong winds and earthquakes, among other inputs. When the bridge carries heavy traffic, vibrations in the bridge structural elements subjected to high levels of stress. This tension bridge subjected to fatigue. This paper studies and focus the effects of vibration of steel truss bridges and finally to suggest future directions of research and innovation. The possibilities of modal properties of global and local vibration method in determining the structural changes in the truss bridges discussed located to the results of finite element analysis

Optimization of Asymmetric Magnetic Recording Heads Inclination Angle and Study the Characteristics for a Higher Bit Density Recording of HDD

This paper study the optimization of the asymmetric magnetic recording heads, the calculations demonstrate sharp field gradient performance for both the horizontal, and vertical field components for this type magnetic recording heads at large inclination and small distance between the head and underlayer. In addition, the characteristics for a higher bit density recording of HDD have been studied. These characteristics can be utilized to raise bit density in both recording method conventional and vertical, respectively