A High-gain, fully balanced preamplifier is presented. The proposed structure advantages flipped voltage follower scheme to achieve a compact current conveyor with very low input impedance. The presented current conveyor then is used as a core element to realize a high-gain, gm-enhanced trans-conductance amplifier. The presented amplifier is suitable for application as a preamplifier. The high gain of amplifier makes it very suitable to be configured in a feedback form to deliver a high-precision predefined or programmable amplification gain. The proposed structure draws a very low power of 150nW from a 0.6V supply voltage. The Spectre Post-layout simulations with TSMC 180nm CMOS technology have been performed. The proposed amplifier exhibits an open-loop DC gain of 141.5dB and 3-dB frequency bandwidth of 2.4kHz at 60dB closed-loop configuration. The load capacitance is set to be 5pF. The proposed structure also delivers high CMRR and PSRR values of 148.3dB and 153.7dB, respectively.

Production of massive gas fields in Bangladesh is nearing to be ended in the near future.As global energy demands rise due to the rising population and rapid urbanization, maximizing available resources use has become essential. Therefore, preparing the field’s measurement to extend the field’s lifetime needs to get attention. One such measure is enhanced gas recovery (EGR); it is a potential technique to maximize the efficiency of the recovery process, which utilizes fracturing, water flooding, and gas injections to increase gas production. In this study, a simulation of the performance of three EGR techniques with linear, triangular, and corner injection well placements is presented; and thereby, the simulation results of the techniques are analyzed. Simulation of water flooding, CO2 injection, and WAG (water alternating CO2 gas) techniques are performed to evaluate the performance of the reservoir under these injections. A suggestion has been provided in favor of the suitable approach among them. The performances are evaluated based on two factors: the amount of additional gas which has been recovered and the quality of the produced gas. After analyzing the results for each case scenario, it is concluded that CO2 injection can be applied to increase natural gas recovery up to 24.55% more than the base case model. In comparison, the water flooding and WAG models contributed 16.57% and 8% more gas recovery, respectively. The EGR techniques are simulated using the GASWAT feature in the fully implicit formulation of the E300 compositional simulator, a tool of the ECLIPSE suite. Finally, by analyzing the performances of three EGR techniques, this simulation study suggests the CO2 injection model as the most suitable EGR technique over the water flooding and WAG models in terms of more gas recovery.

Production of massive gas fields in Bangladesh is nearing to be ended in the near future.As global energy demands rise due to the rising population and rapid urbanization, maximizing available resources use has become essential. Therefore, preparing the field’s measurement to extend the field’s lifetime needs to get attention. One such measure is enhanced gas recovery (EGR); it is a potential technique to maximize the efficiency of the recovery process, which utilizes fracturing, water flooding, and gas injections to increase gas production. In this study, a simulation of the performance of three EGR techniques with linear, triangular, and corner injection well placements is presented; and thereby, the simulation results of the techniques are analyzed. Simulation of water flooding, CO2 injection, and WAG (water alternating CO2 gas) techniques are performed to evaluate the performance of the reservoir under these injections. A suggestion has been provided in favor of the suitable approach among them. The performances are evaluated based on two factors: the amount of additional gas which has been recovered and the quality of the produced gas. After analyzing the results for each case scenario, it is concluded that CO2 injection can be applied to increase natural gas recovery up to 24.55% more than the base case model. In comparison, the water flooding and WAG models contributed 16.57% and 8% more gas recovery, respectively. The EGR techniques are simulated using the GASWAT feature in the fully implicit formulation of the E300 compositional simulator, a tool of the ECLIPSE suite. Finally, by analyzing the performances of three EGR techniques, this simulation study suggests the CO2 injection model as the most suitable EGR technique over the water flooding and WAG models in terms of more gas recovery.

Spermatogonial Stem Cells (SSCs) are the only stem cells in adults that can transfer genetic information to future generations. Considering that a single SSC gives rise to a vast number of spermatozoa, genetic manipulation of these cells is a potential novel technology with feasible application to various animal species. The aim of this study was to evaluate Enhanced Green Fluorescent Protein (EGFP) gene transfection into bovine spermatogonial colonies via Turbofect carrier and assess the best incubation day in uptake exogenous gene by spermatogonial colonies. Transfection efficiency EGFP gene through Turbufect was determined different three days (day 4, 6 and 8) after the beginning of the culture by fluorescent microscope. Immunofluorescent staining against OCT4 and Vimentin led to the confirmation of the nature of both SSCs and sertoli cells. Results showed that the transfected colonies through Turbufect increased significantly (p<0.05) in each three days of transfection in comparison with those of the control groups. The transfection colonies were higher (significant) in comparision with those of the free exogenous gene carrier groups. The rate of infected colonies was higher when transfection proceed day 4. It was concluded that Turbofect can be used safely for direct loading exogenous DNA to spermatogonila colony particulary during the fourth day of culture.

One of the obvious reasons for most disorders in network service provisioning is network path congestion. Congestion avoidance in today's networks is too costly and sometimes impossible. With the introduction of SDN, centralizing the equipment's control plane has become possible. This paper presents an enhanced method named ESV-DBRA to avoid congestion in multi-tenant SDN networks. At first, ESV-DBRA monitors the traffic load and delay of all network paths for each tenant individually. Then, by merging the parameters obtained from the monitoring, the Service Level Agreements (SLA), and a novel proposed cost function, it calculates the cost of the network paths per tenant. As a result, traffic for each tenant is routed through the path/paths at the lowest possible cost from the tenant's perspective. Next, the bandwidth quotas will be calculated and assigned to the tenants over their optimal routes. Afterward, whenever congestion is likely to occur in a path, ESV-DBRA automatically changes the route or bandwidth of the tenants' traffic related to this path to avoid congestion. Related algorithms are also proposed.Eventually, simulations show that the proposed method effectively increases bandwidth utilization by 10.76%.

Microbial enhanced oil recovery method (MEOR) refers to all processes thatuse the capabilitie of various microorganisms to produce microbial metabolites to improve the efficiency of oil extraction. One of this metabolites, isbiosurfactant. Biosurfactants are surface active compounds that dissolve organic compounds in inorganic compounds by reduction the surface tension. In this paper will have an overview on methods and the advantages of using biosurfactants and effective factors in production and the impact of environmental condition on biosurfactantperformancein microbial enhanced oil recovery.