The efficiency of solar energy absorption in solar heaters is increased by the use of selective absorption coating that possesses high absorption of solar radiation in the UV-visible spectrum as well as low emission at the operating temperature in the infrared region. In this work, novel selective coatings were synthesized by improving the selectivity of chromium oxide (Cr₂O₃) nanoparticles by doping with carbon nanoparticles using the exploding wire technique for carbon rods by high current in suspended Cr₂O₃ particles. The structural properties and surface topography were studied by XRD and FE-SEM, which illustrate the carbon-coated Cr₂O₃ nanoparticles. The prepar

      The dielectric properties of the fabricated composites MgO:ZnO with various mixing ratios (100,75:25,50:50,25:75, and 100 wt. %)were investigated. The structure analysis was conducted using X-ray diffraction. The structure phase, crystallite size and purity of the fabricated MgO:ZnO composites were confirmed using X-ray diffraction spectra. The results declared that the diffraction spectrum of 100%MgO composite samples were compatible with cubic structure along the plane (200) while the structures of residual composite's samples were compatible with hexagonal structures. The crystal size of the most pronounced plane (101) for crystal growth was changed from 30.4 nm to 53.2 nm by increasing ZnO ratio from 25 to 100wt%. The diel

As one type of resistance furnace, the electrical tube furnace (ETF) typically experiences input noise, measurement noise, system uncertainties, unmodeled dynamics and external disturbances, which significantly degrade its temperature control performance. To provide precise, and robust temperature tracking performance for the ETF, a robust composite control (RCC) method is proposed in this paper. The overall RCC method consists of four elements: First, the mathematical model of the ETF system is deduced, then a state feedback control (SFC) is constructed. Third, a novel disturbance observer (DO) is designed to estimate the lumped disturbance with one observer parameter. Moreover, the stability of the closed loop system including controller

Biological study was conducted in the botanical garden of the College of Education / Ibn Al-Haitham during the growing season 2006-2007 to determine the impact different date planting and variety in some morphological characteristics of the wheat plant Triticum astivum L.       Two varieties of Triticum aestivum L.: IPA99 and Abu-Ghraib , were cultivated in 4th , 25th of November and 9th of December .      The experiment was designed according to RCD in two replicates.       The results showed that cultivation of 4th November, gave rise to plants of high 74.66 cm, with the highest number of tillers which was 4.01 and the highest length of spike was 12.03

The present paper discusses morphological and syntactic structures of time in Russian language. The morphological and syntactic structures are considered part component of time category in Russian language.

The morphological categories of time are formed through a various types of expressions .Tenses generally express time relative to the moment of speaking. In some contexts, however, their meaning may be relativized to a point in the past ,present or future which is established in the discourse .Some languages have different verb forms or constructions and that are opposed in meaning not in syntactic category. Hence, the present study traces and compares the syntacti

The study included the description of external body parts and the male genitalia for the male of rusty flour beetle Tribolium castaneum (Herbst,1797) and the studied was supported by illustrations

The current works included morphological features study (vegetative and floral parts) for five species of the genus Silene L., S. ampullata, S. chlorifolia, S. colorata, S. conoidea and S. longipetala belong to the family Caryophyllaceae, samples were collected from various areas of northern Iraq. Confirmation in the description was on the most critical parts of the plant, including the shape of the leaves, length, and shape of the calyx tube and venation, the modification shapes of coronal scales petals and appendages, anther ornamentation and structures of pistils. Images enhanced the morphological characteristics under study. Information on the locations and dates of the collection

Background: The surface properties of the titanium alloy plays a significant role in the bond of the dental implant with living bone and modification of the implant surface could enhance osseointegration. This study was aimed to investigate the effect of different durations of heat treatment on the surface properties of titanium alloy for dental implants. Materials and methods: Twenty disks of (Ti-6Al-4V) alloy were prepared. The sample was divided into four test groups to study the effect of different duration of heat treatment to the surface topography; surface chemistry, titanium oxide layer thickness, blood contact angle, & blood drop diameter of titanium alloy samples were investigated to evaluate the effect of different durations of

The objective of this research was to investigate the effect of replacing fat(shortening) with different percentages of tahena on the quality properties (physiochemical and sensory ) of shortened cake.The percentages of moisture,protein ,fat and ash of cake increased significantly(p<0.05) as the replacement was increased .The highest increase percentages were 10,48,5,and 90 %,respectivly, at 100% replacement .Carbohydrate,however,decreased by 10%at 100% replacement .these findings may indicate improvement of cake nutritional value.Standing height,as an indicator of cake volume, also increased significantly by 4% at the 50% replacement then it decreased by 4% 100% replacement level. Basic formula (control) has signific