Frequency reconfigurable patch antenna for 4G LTE applications

A compact printed multi-band frequency reconfigurable patch antenna for 4G LTE applications is presented in this paper (50 x 60 x 1.6 mm3). The antenna consists of W-shaped and Inverted-U shaped patch lines connected in a Tree-shape on the front side of the antenna. The back-side of the antenna contains a 90°-tilted T-shaped strip connected with an Inverted-L shaped strip which is shorted with a patch on the front side for increasing the electrical length to cover lower frequency bands. Frequency reconfigurability is achieved by inserting three switches i.e., PIN diodes. The most critical part of this work is the designing of RLC-based DC line circuits for providing the DC biasing to the PIN diodes used as switches and inserting them at optimum locations. This antenna is reconfigurable among eight different 4G LTE frequency bands including 0.9 GHz, 1.4 GHz, 1.5 GHz, 1.6 GHz, 1.7 GHz, 1.8 GHz, 2.6 GHz, 3.5 GHz and WLAN band 2.5 GHz. The antenna exhibits different radiation patterns having a different direction of peak gain at different frequencies and for different switching combinations. The antenna is simulated with CST, and a prototype is fabricated to compare the measured and simulated results with good accuracy

Isolation of keratinophilic fungi and aerobic actinomycetes from park soils in Gorgan, North of Iran

Background: Keratinophilic fungi are a group of fungi that colonize in various keratinous substrates and degrade them to the components with low molecular weight. This study was conducted to determine the prevalence of keratinophilic fungi and aerobic Actinomycetes in soil of city parks in Gorgan. Objectives: In this study, we surveyed the city park soils of Gorgan (a northern province of Iran) to determine the identities and diversity of soil aerobic Actinomycetes, keratinophilic and non-keratinophilic fungi. Materials and Methods: A total of 244 soil samples were collected from 22 diferent parks of Gorgan, North of Iran. The samples were collected from the superfcial layer with depth not exceeding than 0-10 cm in sterile polyethylene bags. We used hair bait technique for isolation keratinophilic fungi. The colonies identifed by macroscopic and microscopic characterization after slide culturing. Actinomycetes were isolated by antibiotic dilution methods and detected by using physiological tests such as Lysozyme, Casein, Xanthine, Hypoxanthine, Gelatin, Urea Broth, and modifed acid-fast stain. Results: Totally, 75 isolates of aerobic Actinomycetes were detected that Actinomadura madurae and Nocardia asteroides were the most prevalent strains, with 14.66 and 28% prevalence respectively. Microsporum gypseum was more frequent than other keratinophilic fungi (22.96%) and Aspergillus spp. was the most species of saprophyte fungi (15.92%). Conclusions: This study showed that the collected soil from studied areas was rich of keratinophilic fungi and Actinomycetes, therefore hygiene protocol should be taken to prevent the spread of pathogenic and saprophytes fungi in the environment of susceptible person. © 2013, Ahvaz Jundishapur University of Medical Sciences

Causality between Energy Consumption and Economic Growth in Pakistan

The objective of this study is to examine the causality between energy consumption and economic growth in Pakistan over the period of 1991 to 2006. Pakistan has been facing severe energy crises in the current period and the condition is deteriorating day by day. By applying technique of Granger causality and unit root test, the results infer that electric power consumption is granger causing GDP growth. The implications of the study are that energy conservation policy regarding consumption of energy would not lead to any side-effects on economic growth in Pakistan. The country needs a quantum jump in electricity generation in medium-term scenario to revert the possibilities of load shedding in future due to shrinking gap between demand and supply of electricity. Keywords: Granger test, GDP, energy consumption

Deformation behavior and processing map of ATI 425 with initial lamellar microstructure

The effect of hot compression temperatures and strain rates on deformation behavior and resultant microstructure of ATI 425 alloy with initial lamellar microstructure was investigated in this study. The temperature and strain rate of the hot compression test were chosen to be in the 700-1100 °C and 0.001-1 s-1 ranges, respectively. The stress-strain curve and microstructure evaluation show that the alloy's flow softening is associated with globularization and dynamic recrystallization mechanisms. The constitutive equation calculates the activation energy for the α/β and β regions to be 348 kJ/mol and 201 kJ/mol, respectively. Dynamic recovery and partial recrystallization are the dominant structure modification mechanisms in the beta single-phase region. Bending and fragmentation of alpha plates is the dominant mechanism of microstructure promotion in the α/β region at low temperatures and low strain rates, less than 0.1s-1. Local shear and alpha plate break-up are the main factors in structural modification at high strain rates, greater than 0.1s-1. The extracted process map at 0.5 strain revealed three zones: instability, safe zone, and peak zone, with power dissipation efficiencies of 0 -0.25%, 30-40%, and above 40%

Comparison of adaxial and abaxial spectral reflectance of Fagus orientalis Lipsky and Carpinus betulu using field spectroradiometer and spectral indices

The spectral reflectance of tree crown can be different from spectral reflectance of its leaves because of diverse leaf and branch angles as well as internal space of tree crown. For these reasons it is necessary to study spectral reflectance of both adaxial and abaxial surfaces of the leaves. Such information is necessity for modeling the reflectance of tree crown and forest stands. The main objective of this study was to obtain and study the spectral reflectance of both adaxial and abaxial leaves of beech and hornbeam in natural condition and to investigate their spectral differences using indices sensitive to chlorophyll, chlorophyll to carotenoid ratio and photosynthetic pigments. Field spectroradiometric measurements were performed using a portable spectroradiometer (ASD FieldSpec) in Kheyrud forest. A total of 52 trees were sampled and 312 spectra were recorded and analyzed. Spectral measurements cover the wavelength range between 350 – 2500 nm. The results of the spectral reflectance analysis of these two species showed that the abaxial spectral reflectance from 350 to 2500 nm was higher than the adaxial one for hornbeam species. However, for beech species in the visible region and far infrared region, the abaxial spectral reflectance was higher whereas in the near infrared it was lower than the adaxial one. For more detailed investigation of spectral reflectance difference for these two species, spectral indices sensitive to chlorophyll and carotenoid were calculated and statistically analyzed for both surfaces. The value of adaxial NDI index was found to be higher than abaxial for both species. In contrast, the values of adaxial SIPI and PRI indices were lower than abaxial. The differences significant (?= 0.01, p< 0.0001) for both species

Spectral reflectance of rice canopies and red edge position (REP) as indicator of High yield varieties

Rice is the staple food in Iran. More than 80 percent of rice area is distributed in the two northern provinces of Mazandaran and Gilan, so that investment in increasing the quantity and quality can impact an effective role in economic independence and sustainable agriculture. Increased efficiency in rice production is possible through varietal technology, advances in yield enhancement, and the successful development of hybrid technology. Nondestructive methods such as study the spectral reflectance of rice fields is a reliable way in remote sensing study. In this study we tested the possibility to predict highyielding rice varieties based on the spectral reflectance data in the red edge position (REP). Spectral reflectance of rice canopies from 350 to 2500 nm were acquired under clear sky in rice filed. The obtained results indicate that REP of Hybrid, Tarom, Neda and Khazar varieties are at longer wavelength, so they are predicted as more productive rice varieties

Experimental correlation of natural convection losses from a scale-model solar cavity receiver with non-isothermal surface temperature distribution

Correlations for natural convection heat loss from solar cavity receivers are widely based on isothermal surface temperature assumptions, which do not occur in practice due to the local heat balance varying with position. An open question thus exists regarding the suitability of such correlations for non-isothermal conditions. This paper addresses this issue by presenting a new Nusselt correlation developed from an experimental investigation of natural convection heat loss from a non-isothermal scale-model cylindrical cavity receiver. Cavities that are considered in this work have length-to-diameter ratios of 1 and 2, are operated at peak temperatures ranging from 355 °C to 650 °C, and exhibit temperature differences along the cavity wall between 40 °C and 342 °C. Stagnation and convection zones, as well as view factor profiles, are observed to contribute to the wall temperature distribution as the cavity is inclined downwards. An energy balance undertaken for steady state provides insight into the effects of non-uniform surface temperature distribution and inclination-dependent surface areas on radiative and convective losses. Natural convection heat loss results from this work are compared with widely-used correlations from the literature that assume isothermal wall conditions, and systematic discrepancies are observed. The proposed Nusselt correlation which accounts for the temperature non-uniformity, cavity inclination and geometric aspect ratio is evaluated against experimental data from this and other studies. It is found to produce excellent predictions of Nusselt numbers for cylindrical cavity receivers in the Grashof number range of 2.6 × 105 to 1.4 × 107