Wireless channels are typically much more noisy than wired links and subjected to fading due to multipath  propagation which result in ISI and hence high error rate. Adaptive modulation is a powerful technique to improve the tradeoff between spectral efficiency and Bit Error Rate (BER). In order to adjust the transmission rate, channel state information (CSI) is required at the transmitter side.

In this paper the performance enhancement of using linear prediction along with channel estimation to track the channel variations and adaptive modulation were examined. The simulation results shows that the channel estimation is sufficient for low Doppler frequency shifts (<30 Hz), while channel prediction is much more suited at

This study was investigated the role of garlic extracts on the reproductive functions, via the development of immature male mice (25 days old) un l puberty. Immature male mice were divided into 3 groups (n=25). Group 1 "control" was daily administrated with tap water. Group 2 was daily administrated with cold aqueous garlic extract. Group 3 was daily administrated with hot aqueous garlic extract. Each group was randomly consisted of 5 subgroups (n=5/ subgroup) and administrated for different periods i.e, 1, 2, 3, 4 and 5 weeks respectively. Animals were scarified after 24 h from last treatment. Our findings elucidated that, cold and hot aqueous garlic extracts, when administrated at 25 days old (Immature period) have different impact dep

Background: Dental implants act as infrastructure for fixed restoration to look like as a natural tooth. Osseointegration is a biological events and considered as a base for success of dental implant. The aim of this study is to evaluate the bond strength between bone and Ti implant coated with mixture of nano hydroxyapatite-chitosan-collagen compared with Ti implants coated with nano hydroxyapatite implanted in rabbit tibia, after different period of implantation time (two and six weeks) by torque removal test. Material and methods: 36 screws of commercially pure titanium; 8mm in length and 3mm diameter , 18 screws coated with mixture of nano hydroxyapatite-chitosan-collagen and18 screws coated with nano hydroxyapatite by dip coating. St

This project sought to fabricate a flexible gas sensor based on a short functionalized multi-walled carbon nanotubes (f-MWCNTs) network for nitrogen dioxide gas detection. The network was prepared by filtration from the suspension (FFS) method and modified by coating with a layer of polypyrrole conductive polymer (PPy) prepared by the oxidative chemical polymerization to improve the properties of the network. The structural, optical, and morphological properties of the f-MWCNTs and f-MWCNTs/PPy network were studied using X-ray diffraction (XRD), Fourie-transform infrared (FTIR), with an AFM (atomic force microscopy). XRD proved that the structure of f-MWCNTs is unaffected by the synthesis procedure. The FTIR spectra verified the existence o

Mixed convection heat transfer to air inside an enclosure is investigated experimentally. The bottom wall of the enclosure is maintained at higher temperature than that of the top wall which keeps in oscillation motion, whereas the left and right walls are well insulated. The differential temperature of the bottom and top walls changed several times in order to accurately characterize the temperature distribution over a considerable range of Richardson number. Adjustable aspect ratio box was built as a test rig to determine the effects of Richardson number and aspect ratio on the flow behavior of the air inside the enclosure. The flow fields and the average Nusselt number profiles were presented in this wo

Gypseous soils are widely distributed and especially in Iraq where arid area of hot climatic is present. These soils are considered as problematic soils; therefore this work attends to improve the geotechnical properties of such soil and reduce the dangers of collapse due to wetting process. In this research, undisturbed soil sample of 30 % gypsum content from Karbala city is used. The Single Oedometer collapse test is used in order to investigate the collapse characteristics of natural soil and after treatment with 3%, 6%, 9%, 12% and 15% of Cutback Asphalt. Moreover, two selected additive percentages (9% and 12%) are used to evaluate the suitability of using the Cutback Asphalt for improvement of the bearing capacity o

Hydro cracking of heavy oil is used in refinery to produce invaluable products. In this research, a model of hydro cracking reactor has been used to study the behavior of heavy oil in hydro cracking under the conditions recommended by literature in terms lumping of feed and products. The lumping scheme is based on five lumps include: heavy oil, vacuum oil, distillates, naphtha and gases. The first order kinetics was assumed for the conversion in the model and the system is modeled as an isothermal tubular reactor. MATLAB 6.1 was used to solve the model for a five lump scheme for different values of feed velocity, and temperature.