In this paper octagon shape planar microstrip antenna is presented. Octagonal antenna can find applications in Radar and Space-crafts. The antenna is fed by a 50 Ω microstrip line and printed on a dielectric Fr4 substrate of dimension (22mm X 22 mm) permittivity εr =4.4 and height h = 1.6 mm. The optimization on the planar octagonal microstrip has been done to accomplish an -10 dB return loss b...

The portable generators are the main means of compensating the shortage of national electricity power as in Iraq. However, their noise causes a huge disturbance, uncomforting and loss of concentration of the nearby resident. This problem requires a solution because most shops and residential houses use generators. Covering method is a simple and relatively low cost one for reduction of generato...

we derived explicit formulae for the eccentric connectivity index and wiener index of2-dimensional square-octagonal tuc4c8(r) lattices with open and closed ends. newcompression factors for both indices are also computed in the limit n-->∞.

Three enclosures (10 x 10 x 1.5-1.3 m in depth) were set beside Dianch Lake, Kunming, People's Republic of China, for the period from July 28 to August 26, 2002. The enclosures were filled with cyanobacterial (Microcystis aeruginosa) water bloom-containing lake water. Lake sediment that contained macrophytes and water chestnut seeds was spread over the entire bottom of each enclosure. Initially...

this study describes the design, construction and calibration of an adjustable three-point hitch dynamometer. the dynamometer frame design was based on an inverted u-shaped frame that was mounted between the tractor links and implement. the dynamometer frame design allows for use in both category i and ii three-point hitch systems because of its flexibility in a lower point hitch spread and mas...

livestock grazing is one of the most important kinds of land usage that has a high potential to decrease or increase carbon storage in rangeland ecosystem. this research was investigated the effects of enclosure on soil carbon storage in a rangeland with dominant plants of artemisia aucheri. hence, two rangelands of enclosure (shahtappeh-chah mahmood) and no enclosure (chiro) were chosen in sem...

Based on the necessity for enclosure protection of temperature and relative humidity sensors installed in a hostile environment, a wind tunnel was used to quantify the time that the sensors take to reach equilibrium in the environmental conditions to which they are exposed. Two treatments were used: (1) sensors with polyvinyl chloride (PVC) enclosure protection, and (2) sensors with no enclosur...

At present advanced projects of the early XXI century are beginning to develop. These projects include lunar base development and manned missions to Mars. The space suit is one of the basic requirements for successful implementation of future programs. The space suit enclosure enables mobility of crewmembers wearing pressurized space suits which will be required to complete these missions. Requ...

The epiboly of the Caenorhabditis elegans hypodermis involves the bilateral spreading of a thin epithelial sheet from the dorsal side around the embryo to meet at the ventral midline in a process known as ventral enclosure. We present evidence that ventral enclosure occurs in two major steps. The initial migration of the hypodermis is led by a quartet of cells, which exhibit protrusive activity...

The earliest food producers in Africa were mobile pastoralists who left limited archaeological traces. As a result archaeologists studying the spread of food production in the region have difficulty distinguishing early pastoralists from hunter-gatherers with whom they interacted. This geo-ethnoarchaeological study contributes to the resolution of the problem through identification of sediments...