A HIGH PERFORMANCE FULLY DIFFERENTIAL PURE CURRENT MODE OPERATIONAL AMPLIFIER AND ITS APPLICATIONS

In this paper a novel high performance all current-mode fully-differential (FD) Current mode Operational Amplifier (COA) in BIPOLAR technology is presented. The unique true current mode simple structure grants the proposed COA the largest yet reported unity gain frequency while providing low voltage low power operation. Benefiting from some novel ideas, it also exhibits high gain, high common mode rejection ratio (CMRR), high power supply rejection ratio (PSRR), high output impedance, low input impedance and most importantly high current drive capability. Its most important parameters are derived and its performance is proved by PSPICE simulations using 0.8 μm BICMOS process parameters at supply voltage of ±1.2V indicating the values of 82.4 dB,52.3º, 31.5 Ω, 31.78 MΩ, 179.2 dB, 2 mW and 698 MHz for gain, phase margin, input impedance, output impedance, CMRR, power and unity gain frequency respectively. Its CMRR also shows very high frequency of 2.64 GHz at zero dB. Its very high PSRR+/PSRR- of 182 dB/196 dB makes the proposed COA a highly suitable block in Mixed-Mode (SOC) chips. Most favourably it can deliver up to ±1.5 mA yielding a high current drive capability exceeding 25. To demonstrate the performance of the proposed COA, it is used to realize a constant bandwidth voltage amplifier and a high performance Rm amplifier

Comparative Study of Growth Patterns for Three Strains of Broiler Chickens Using Mathematical Models

The aim of the current study was to investigate the growth pattern of three genetic strains of broiler chickens including Ross 308, Cobb and Arbor Acres by mathematical models. For this purpose, the body weight of 500 broilers for each strain was recorded weekly. Gompertz, Logistic and Richards functions were considered for data fitting. Three functions were compared by adjusted determination coefficient (R2) and root mean square error (RMSE). For all three models, R2 had high values, ranging from 0.987 to 0.999. The difference among the fitted functions by RMSE was significant compared to the R2. The Richards function had more appropriate description for the growth curve of the Cobb strain, because of having the minimum RMSE, 61.57 compared to 85.43 and 66.61, for Gompertz and Logistic functions, respectively. However, the Gompertz function with the maximum R2, and the minimum RMSE, 73.32 and 3237, respectively, was the most suitable function to describe the growth curve of Arbor Acres strain

The effects of water potential on some microbial populations and decrease kinetic of organic carbon in soil treated with cow manure under laboratory conditions

The moisture content of the soil habitat is an important stress factor and effects on soil microbial population and activity. The objectives of this study were to test the effects of water potential on the decrease kinetic of soil organic carbon (OC), some microbial populations and their activities in a soil treated with cow manure. A semiarid soil was treated with raw cow manure (CM) at a rate of 20 g kg-1. Three water potentials established for soil incubation were: saturation (SAT, 0 bars), field capacity (FC, -0.3 bars), and permanent wilting point (PWP, -15 bars). Fourth irrigation treatment was drying-rewetting cycle (D-W) between -0.3 to -15 bars. After 0, 10, 20, 40, 60 and 90 days of incubation, soils were sampled for analysis. Colony forming units of bacteria, actinomycetes and fungi and soil OC, basal respiration (BR) and substrate induced respiration (SIR) were measured. The effects of soil moisture, incubation time and their interactions on all of the studied properties and kinetic parameter for OC decrease were significant. The populations of bacteria and fungi were the highest in the soils incubated in DWC and PWP respectively. The population of bacteria decreased significantly with increasing time of incubation. The population of fungi was the lowest in soil incubated in SAT condition and decreased continuously. However fungal population in soil incubated in other moisture increased significantly with increasing time of incubation. The population of actinomycetes was the highest in soil incubated in SAT condition in the early stages of incubation but it was decreased significantly with increasing time in soils incubated in SAT, FC, and DWC. Soil BR and SIR were significantly higher in SAT condition and lower in PWP condition compared to those in other water potentials. However both BR and SIR decreased significantly during soil incubation. Soil OC was significantly higher in SAT and PWP conditions due to unsuitable soil aeration and moisture for OC mineralization. The power function equation was the best model for decrease kinetic of OC in soil incubated in SAT and PWP conditions. However the second order equation was the best model for decrease kinetic of OC in soil incubated in FC and DWC conditions

Comparison of Charge-Coupled Devices and Photostimulable Phosphor Storage Plates for Detection of Vertical Root Fractures in Endodontically Treated Teeth: An In Vitro Study

Objective: Vertical root fracture (VRF) is among the most common causes of endodontic treatment failures. This study aims to compare charge-coupled devices (CCD) and photostimulable phosphor plates (PSP) for detection of vertical root fractures in endodontically treated teeth.Methods: In this diagnostic in vitro study, 40 maxillary anterior teeth were selected and after preparation and root canal filling, their crowns were cut 2mm above the cementoenamel junction (CEJ). The teeth were embedded in a piece of dried bone and radiographed using CCD and PSP with equal geometry at zero and 15° horizontal angles. VRFs were then induced and the fractured fragments were reattached. The teeth were radiographed again. Three observers evaluated the radiographs for detection of fracture line. Data were analyzed using the Proportion test and Wilcoxon’s Signed Ranks test.Results: No significant difference was found between the two sensors in detection of VRFs [p-value (complete)= 0.592, p-value (absolute)= 1]. The sensitivity of the two sensors for detection of buccolingual and mesiodistal fractures was not significantly different [p-value BL (absolute)= 0.109, p-value BL (complete) 0.180] [p-value MD (complete)=0.593, p-value MD (absolute)= 0.102]. The sensitivity of both sensors for detection of buccolingual fracture was higher than for mesiodistal fractures (p<0.001).Conclusion: CCD and PSP had equal efficacy for detection of VRFs in endodontically treated teeth

Experimental and numerical investigation of hydro-forming of stepped tubes for aluminum alloy 6063

In this work, hydro-forming of stepped tubes for aluminum alloy 6063 is investigated experimentally and numerically. Experimental investigations are performed using a die set with new design in bush driving mechanism. Also, numerical simulations are done with finite element software, Abaqus 6.14-4. In the experiments, a new mechanism is proposed for production a stepped tube with sharp corners and high expansion ratio. Also, the effects of some process parameters such as internal pressure, die stroke and friction coefficient on filling of the die and also minimum wall thickness are investigated. The results show that using the proposed mechanism in this paper, a stepped tube with sharp corners and high expansion ratio can be manufactured. Also, it is concluded that better filling of the die is happened with an increase in the die stroke and internal pressure. Also, the reduction of wall thickness is increased with increasing the die stroke, internal pressure and friction coefficient

Modelling the biological aspects of broiler breeding: integrated and non-integrated systems

The objective of present study was to derive the economic values for important traits   in broiler breeding program and to specify their sensitivity to production circumstances, using a deterministic bio-economic model, reflecting an integrated or non-integrated broiler chicken’s production system. Model focuses on multiplier breeder, hatchery, commercial grower and processor stages. The estimated economic values ranged from -0.2035 to 0.2318 for both integrated and non-integrated systems. The estimated economic values based on non-integrated system were higher than those of integrated system except for hatching   egg number (0.0009 vs. 0.0014), mortality (-0.0078 vs. -0.0068) and wings yield (0.0206 vs. 0.0158). In integrated situation, the effect of changes in the mean of hatching egg number, finishing weight and mortality on the economic values of traits was examined. The results showed that hatching egg number did not affect the economic values of traits at the preceding stages. On the other hand, changes in traits at the commercial grower, namely finishing weight and mortality affected the economic values of traits at both commercial grower and processor stages. The results of sensitivity analysis (± 20%) showed that traits at the multiplier and hatchery stages were sensitive to changes in feed costs at rearing and laying periods and also changes in the price of parental stock chicks, but the traits relating to commercial stage did not show any sensitivity to these factors. Among different factors, feed cost in commercial stage had the most impact on economic values of finishing weight, feed consumption and mortality

Eosinophilic Gastroenteritis as a Rare Cause of Recurrent Epigastric Pain

Eosinophilic gastroenteritis (EGE) is a rare inflammatory disorder of gastrointestinal tract characterized by eosinophilic infiltration of the bowel wall. It can mimic many gastrointestinal disorders due to its wide spectrum of presentations. Diagnose is mostly based on excluding other disorders and a high suspicion. Here we report a case of 26 year old man with a history of sever epigastric pain followed by nausea, vomiting since a few days before admission with final diagnosis of EGE