Aeronautical telemetry system is applied to real flight conditions and movements so as to test the efficiency of different parts of an air vehicle such as an airplane, a missile, and a space shuttle during the flight. In order to study, determine and lessen the deleterious effects of the air vehicle's flight maneuvers upon the aeronautical telemetry RADIO LINK, an urgent need for measuring the instantaneous communication angles between the telemetry receiver antenna and the transmitter antenna mounted on the air vehicle is highlighted. In the context of the values of these instantaneous communication angles, the gain from the telemetry receiver antenna and from the transmitter antenna throughout the flight trajectory can be obtained. It should be noted that in most previous studies, however, the gain from the receiver antenna during the test has been assumed to remain constant because the telemetry receivers have been provided with a system of auto-tracking the air vehicles. In order to study the improvements suggested by using coding, modulation, and other communication techniques and methods in the aeronautical telemetry RADIO LINK, a suitable model of real telemetry canal should be developed. By use of particular aeronautical navigation equations, the present paper is going to first develop an algorithm for measuring the instantaneous communication angles between the telemetry receiver antenna and the air vehicle during the flight. The equations are thus solved. After working out the equations, the value of the instantaneous power received by the receiver at any instant of the flight can be determined. On the basis of the suggested algorithm and through the simulation of the RADIO LINK (along the entire flight trajectory of an assumed air vehicle) the probability of the bit error rate of the collected data for some propagation environment of aeronautical telemetry can be found.

After setteling the LEO satellite in the given circuit, the ground station needs to communicate with it for the received of information and control of its subsystems. Due to the fact that satellite communication channels are influenced by shadowing conditions, if a line of sight (LOS) signal exists between the receiver and the transmitter, then the RADIO channels conditions are good and the Additive White Gaussian Noise channel is modeled as Rician distribution. However, under poor conditions and in the lack of LOS, channel model is Rayleigh, and due to the RADIO LINK conditions the channel will be switched between these two models. In a proper model, the time varying behavior of the station – satellite RADIO LINK should be considered. The importance attached to this issue is due to its considerable effect on the selection of modulation type, design of channel access method, and error control. In this view, the present study has sought to momentarily determine the range of variations in error probability. Through calculations and simulation, the Bit Error Rate received during the satellite trajectory has been obtained for any given moment and its range of variations has been determined.

Abstract: Rain attenuation prediction models are inevitably deployed to provide rough estimates of the actual measured attenuation due to severe scarcity in most of the tropical and equatorial climates. The results of rain attenuation measurements over a 14.8 GHz terrestrial microwave LINK and slant-path attenuation in vertically polarized signals propagating at 10.982 GHz in a tropical Malaysian climate were reported in this study. The experimental results including the path adjustment factors were compared with the predictions of some selected rain attenuation models. The relative errors in the path length adjustment factors (PLAFs) are in the range -0.3370 – 2.6272, while those of the slant path adjustment factors (SPAFs) are -0.9252 – +0.2923. Moreso, the charts of PLAFs and SPAFs at 0.01% of the time were also presented because they are the most commonly used availability by the telecommunications service providers. This study will allow the RADIO engineer to select the most suitable prediction models for the particular region under study, thereby ensuring adequate RADIO planning for improved service delivery especially in the tropical climates due to their peculiarity.

We address the throughput maximization problem for downLINK transmission in DF-relay-assisted cognitive RADIO networks (CRNs) based on simultaneous wireless information and power transfer (SWIPT) capability. In this envisioned network, multiple-input multiple-output (MIMO) relay and secondary user (SU) equipment are designed to handle both RADIO frequency (RF) signal energy harvesting and SWIPT functional tasks. Additionally, the cognitive base station (CBS) communicates with the SU only via the MIMO relay. Based on the considered network model, several combined constraints of the main problem complicate the solution. Therefore, in this paper, we apply heuristic guidelines within the convex optimization framework to handle this complexity. First, consider the problem of maximizing throughput on both sides of the relay separately. Second, each side progresses to solve the complex problem optimally by adopting strategies for solving sub-problems. Finally, these optimal solutions are synthesized by proposing a heuristic iterative power allocation algorithm that satisfies the combinatorial constraints with short convergence times. The performance of the optimal proposed algorithm (OPA) is evaluated against benchmark algorithms via numerical results on optimality, convergence time, constraints’ compliance, and imperfect channel state information (CSI) on the CBS-PU LINK.

The seeds of cultivated Trachyspermum copticum L. LINK collected in autumn from Research institute of Forests and Rangelands field and extracted by water distillation. The average of humidity was 3.8%. Analyses of essential oil were done by GC/MS which were resulted to identify 9 compounds which contains 100% of oil. Among the identified constituents, p- cymene (32.4%), g- terpinene (27.8%) and b- Pinene (1%) were the major constituents. The contents of phenolic compounds were less than those were reported by other scientists in different countries. It considers the soil ingredients, conditions and the methods of extraction were important on the essential oil contents.

Jojoba is considered as a valuable crop species regarding its tolerance to drought and soil salinity as well as its economical importance as an industrial crop. This species is used on soil conservation activities, against desertification, as an ornamental and landscaping plant and in some extend also can be considered as a nutritional plant. Seeds of Jojoba contain 50-60% liquid wax which is used in electronic, medicine, nutrition and cosmetic industries.The result of this experiment showed that application of 70% ethanol for 5 sec followed by 1% (w/v) benomyl for 30 min and 1% (v/v)sodium hypochlorite containing 1-2 drops of liquid detergent for 15 min caused the highest seed surface sterilizing efficiency.The highest germination rates (90%) were obtained when the seeds were incubated in a 27°C dark germinator for 5-13 days.There was significant differences (P < 1%) among seed germination rates. In this experiment seed germination was examined as most convenience and low cost method of Jojoba propagation.