MHD heat transfer in W-shaped inclined cavity containing a porous medium saturated with Ag/Al2O3 hybrid nanofluid in the presence of uniform heat generation/absorption

© 2020 by the Authors. In this paper, a 2D numerical study of natural convection heat transfer in a W-shaped inclined enclosure with a variable aspect ratio was performed. The enclosure contained a porous medium saturated with Ag/Al2O3 hybrid nanofluid in the presence of uniform heat generation or absorption under the effect of a uniform magnetic field. The vertical walls of the enclosure were heated differentially; however, the top and bottom walls were kept insulated. The governing equations were solved with numerical simulation software COMSOL Multiphysics which is based on the finite element method. The results showed that the convection heat transfer was improved with the increase of the aspect ratio; the average Nusselt number reached a maximum for an aspect ratio (AR) = 0.7 and the effect of the inclination was practically negligible for an aspect ratio of AR = 0.7. The maximum heat transfer performance was obtained for an inclination of ω = 15 and the minimum is obtained for ω = 30. The addition of composite nanoparticles ameliorated the convection heat transfer performance. This effect was proportional to the increase of Rayleigh and Darcy numbers, the aspect ratio and the fraction of Ag in the volumetric fraction of nanoparticles

On the Effect of Correlated Measurements on the Performance of Distributed Estimation

We address the distributed estimation of an unknown scalar parameter in Wireless Sensor Networks (WSNs). Sensor nodes transmit their noisy observations over multiple access channel to a Fusion Center (FC) that reconstructs the source parameter. The received signal is corrupted by noise and channel fading, so that the FC objective is to minimize the Mean-Square Error (MSE) of the estimate. In this paper, we assume sensor node observations to be correlated with the source signal and correlated with each other as well. The correlation coefficient between two observations is exponentially decaying with the distance separation. The effect of the distance-based correlation on the estimation quality is demonstrated and compared with the case of unity correlated observations. Moreover, a closed-form expression for the outage probability is derived and its dependency on the correlation coefficients is investigated. Numerical simulations are provided to verify our analytic results.Comment: 5 page

Spectrophotometric Determination of Certain Antiepileptic's in Tablets Using Vanillin Reagent

A selective and new spectrophotometric method is described for determination of three antiepileptic drugs; namely lamotrigine (LAM), gabapentin (GAB), and oxcarbazepine (OXC) in drug substances and in drug products using vanillin reagent as the chromogenic agent. The method is based on a coupling reaction between the cited drugs and vanillin reagent in acidic condition. Under optimized conditions, the yellow colored products were measured at 405, 396, and 400 nm respectively. Beer’s law was obeyed at (0.4 – 10), (0.1-10), and (0.5-11) μg/mL, and  the calculated molar absorptivity values are 2.52 x 104, 1.74 x 104, and 2.54 x 104 L/mol/cm for LAM, GAB, and OXC respectively. Sandell sensitivity, the limit of detection (LOD) and limit of quantification (LOQ) were calculated. No interference was observed from common additives found in drug products. The presented method was validated according to ICH guidelines. Statistical comparison of the results was performed using Student's t-test and F-ratio at 95% confidence level, and there was no significant difference between the reference and proposed method with regard to accuracy and precision. The method offers the advantages of rapidity, simplicity and sensitivity and low cost and can be easily applied to resource poor settings without the need for expensive instrumentation and reagents

Providing Dynamic TXOP for QoS Support of Video Transmission in IEEE 802.11e WLANs

The IEEE 802.11e standard introduced by IEEE 802.11 Task Group E (TGe) enhances the Quality of Service (QoS) by means of HCF Controlled Channel Access (HCCA). The scheduler of HCCA allocates Transmission Opportunities (TXOPs) to QoS-enabled Station (QSTA) based on their TS Specifications (TSPECs) negotiated at the traffic setup time so that it is only efficient for Constant Bit Rate (CBR) applications. However, Variable Bit Rate (VBR) traffics are not efficiently supported as they exhibit nondeterministic profile during the time. In this paper, we present a dynamic TXOP assignment Scheduling Algorithm for supporting the video traffics transmission over IEEE 802.11e wireless networks. This algorithm uses a piggybacked information about the size of the subsequent video frames of the uplink traffic to assist the Hybrid Coordinator accurately assign the TXOP according to the fast changes in the VBR profile. The proposed scheduling algorithm has been evaluated using simulation with different variability level video streams. The simulation results show that the proposed algorithm reduces the delay experienced by VBR traffic streams comparable to HCCA scheduler due to the accurate assignment of the TXOP which preserve the channel time for transmission.Comment: arXiv admin note: substantial text overlap with arXiv:1602.0369

A new clustering technique based on replication for MANET routing protocols

The cluster head nodes in most mobile ad hoc networks (MANET) clustering protocols take on an extraordinary role in managing routing information. The reliability, efficiency and scalability of the clustering in MANET will ultimately be dramatically impacted. In this work we establish a new approach to form the clusters in MANET called the square cluster-based routing protocol (SCBRP). That protocol is based on the theory of replication. The goal of the protocol is to achieve reliability, availability and scalability with in the MANET. The proposed protocol is evaluated by caring the performance analysis using the NS-3 simulator. The performance shows 50% improvementin data delivering ratio in large network size, also shows an improvement in network stability and availability which is reflected in energy consumption measurements and increase in the system lifetime to 20%

Detection of Trypanozoon trypanosomes infections on Glossina fuscipes fuscipes (Diptera: Glossinidae) using polymerase chain reaction (PCR) technique in the Blue Nile State, Sudan

Tsetse flies transmit many species of trypanosomes in Africa, some of which are human and livestock pathogens of major medical and socio-economic impact. Identification of trypanosomes is essential to assess the disease risk imposed by particular tsetse populations. The present study was carried out to determine the trypanosomal infection rate of tsetse flies (Glossina fuscipes fuscipes) in the Blue Nile State of Sudan. A polymerase chain reaction (PCR) assay was used because of the inherent difficulty of speciating trypanosomal parasites in the fly. Our results show that 4.44% (8/180) of the flies were positive for a Trypanosoma brucei group. Three of eight positive flies reacted with primers for Trypanosoma b. rhodesiense. We did not detect flies infected with T. b. gambiense. Thus, the burden of flies harboring T. b. rhodesiense and T. b. brucei trypanosomes were 1.67 and 2.78%, respectively. This is the first evidence of T. b. rhodesiense in the Yabus District. Thus, HAT case-detection active surveillance and tsetse fly control campaigns should be conducted before the establishment of human settlement, investment of natural resources into agricultural and animal husbandry.Key words: Glossina fuscipes fuscipes, Trypanosoma brucei, T. b. gambiense, T. b. rhodesiense, infection rate, PCR technique, Blue Nile State

SHORT NOTE Growth, forage and grain yields of barley as affected by irrigation regime and method of sowing in Sudan Gezira

Barley (Hordium vulgare) is an important multipurpose crop used as feed for animals, malt and human food. Its importance lies in its ability to grow and produce in marginal environments, which are often characterized by drought, low temperature and salinity, (Maas and Hoffiman, 1997 and Baum et al.,2004). Barley is most commonly grown for cereal silage and can produce good yields of high quality feed if water is available. Compared to alfalfa, it grows during a short period and its water requirements are less. The full season water requirements of alfalfa are 900mm of water, one crop of barley silage may only require about 375mm of water for a 7.5 to 10 ton/ha yield. The three years average amount of the applied water for barley on 10 days interval was only 4525 m3/ha, compared to other field crops, the average applied irrigation water for barley is low and water productivity is high even if irrigated every 10 days (Mahasin and Khair, 2014). Hand broadcasting is commonly used to sow wheat (84%) and barley (92%) while covering with mold-board is used to a lesser extent with wheat (48%) than with barley (68%)