The Frequency-hopping Spread Spectrum (FHSS) systems and techniques are using in military and civilianradar recently and in the communication system for securing the information on wireless communications link channels, for example in the Wi-Fi 8.02.X IEEE using multiple number bandwidth and frequencies in the wireless channel in order to hopping on them for increasing the security level during the broadcast, but nowadays FHSS problem, which is, any Smart Software Defined Radio (S-SDR) can easily detect a wireless signal at the transmitter and the receiver for the hopping sequence in both of these, then duplicate this sequence in order to hack the signal on both transmitter and receiver messages using the order of the se
... Show MoreIn cooling water systems, cooling towers play a critical role in removing heat from the water. Cooling water systems are commonly used in industry to dispose the waste heat. An upward spray cooling water systems was especially designed and investigated in this work. The effect of two nanofluids (Al2O3/ water, black carbon /water) on velocity and temperature distributions along reverse spray cooling tower at various concentrations (0.02, 0.08, 0.1, 0.15, and 0.2 wt.%) were investigated, beside the effect of the inlet water temperature (35 ,40, and 45 ͦ C) and water to air flow ratio (L/G) of 0.5, 0.75, and 1. The best thermal performance was found when the working solution contained 0.1 wt.% for each of Al2
... Show MoreBiofilm formation represents one of the biggest problems facing scientists because of this phenomenon linkage with virulence of bacteria and other clinical environmental problems. In the present study, two clinical isolates,
Escherichia coli, and Staphylococcus aureus were exposed to the non thermal plasma for different intervals of time (1, 2, 4, 8, and 16 min). The biofilm was measured post exposing. It was found that 2 min. exposing to non-thermal plasma reduced the biofilm formation by both clinical isolates significantly. It can be concluded that the ability of S. aureus to form biofilm higher than E. coli and exposing for 2 min to non-thermal plasma sufficient to reduce the biofilm formati
The evaluation of the Nfayil limestones in Bahr Al-Najaf Depression as construction materials was done on 15 sites distributed over a region. The study included field and laboratory aspects. The field side included collecting information about the study area and samples. As for the laboratory side, laboratory tests were conducted to study the thermal conductivity of samples by a device called Lee’s disc in the Tikri University. The thermal conductivity results ranged between 2.34 and 0.27. The rocks are of high thermal insulation at low temperatures and low insulation at high temperatures according to the specifications of the suitability of limestone for thermal conductivity standards (ASTM C 1057-03-2010).
This study was carried out at University of Baghdad - College of Agricultural Engineering Sciences - Research Station B during the autumn season 2019-2020, in order to evaluate the effect of Ozone and the foliar application of coconut water and moringa extract on the growth of broccoli plant grown in modified NFT film technology. A factorial experiment (2*5) was carried out within Nested Design with three replicates. The ozone treatment was distributed into the main plots which consisted of oxygen (O2) and ozone (O3). The foliar application of organic nutrients were distributed randomly within each replicate including five treatments, which were the control treatment (T0), Coconut water with two concentrations of 50 (T1) and 100 ml.
... Show MoreThe aim of this paper is to analyzed unsteady heat transfer for magnetohydrodynamic (MHD) flow of a second grade fluid in a channel with porous medium. The equations which was used to describe the flow are the momentum and energy, these equations were written to get thier non dimentional form. Homotopy analysis method (HAM) is employed to obtain a semi-analytical solutions for velocity and heat transfer fields. The effect of each dimensionless parameter upon the velocity and temperature distributions is analyzed and shown graphically by using MATHEMATICA package.
Thin films of ZnSe arc deposited on glass substrates by thermal evaporation in vacuum with different thickness (1000, 2700, 4000) A° temperature (293-373) °K are studies the electrical properties before and after annealing. The result show decrease D.0 conductivity and increasing the activation energy Eat.
ABSTRACT Wound is damage or disruption to the normal anatomical structure and function. Carrageenan is sulphated polysaccharide found in Gigartina, Chondrus and Eucheuma species in the red algal family. Having anticancer, anti-inflammatory and renewal of tissues. Our study aimed to detect the role of kappa carrageenan in the burned skin wound repair. Skin burn were performed in the right and left cheek of 20 male rats (aged 7-8 weeks weighing 300-350 g). Burned skin rats were categorized into two equal groups. Burned areas of right side were treated with a local application of 1 ml of kappa carrageenan solution once daily (treatment group) and the left side receive no treatment (control group). After 5, and 10 days, 5 rats from each
... Show MoreAlthough many technological improvements are occurring in power production worldwide, power plants in third world countries are still using old technologies that are causing thermal pollution to the water bodies. Power facilities that dump hot water into water bodies are damaging aquatic life. In the study, the impact of the Al Dora thermal power plant on a nearby stretch of Tigris River in Baghdad city was assessed by measuring the temperature of the disposed of hot water in various cross-sections of the selected stretch of Tigris River, including measuring the thermal mixing length. The measurements were conducted in winter, spring, and summer. For field measurements, it was found that the impact of recovery distances
... Show MoreThe use of composite materials has vastly increased in recent years. Great interest is therefore developed in the damage detection of composites using non- destructive test methods. Several approaches have been applied to obtain information about the existence and location of the faults. This paper used the vibration response of a composite plate to detect and localize delamination defect based on the modal analysis. Experiments are conducted to validate the developed model. A two-dimensional finite element model for multi-layered composites with internal delamination is established. FEM program are built for plates under different boundary conditions. Natural frequencies and modal displacements of the intact and damaged
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