Simulation and experimental study of the sensor emitting frequency for ultrasonic tomography system in conducting pipe

Ultrasonic tomography techniques provide flow visualization capability, non-invasively and non-intrusively, to enhance the understanding of complex flow processes. There is limited ultrasonic research in tomography imaging systems in the tomogram analysis of fluid flow in a conducting pipe because of a high acoustic impedance mismatch, which means that very little ultrasonic energy can be transmitted through the interface. The majority of industrial pipelines are constructed from metallic composites. Therefore, the development and improvement of ultrasonic measurement methods to accommodate a stainless steel pipe are proposed in this paper. Experimental and simulation distribution studies of the ultrasonic emitting frequency in acrylic versus stainless steel pipes were studied, measured and analyzed. During the simulation, ultrasonic transducers were placed on the surface of the investigated pipe to inspect the ultrasonic sensing field. The distribution of the sound wave acoustic pressure was simulated based on the physical dimensions and parameters of the actual experimental hardware set-up. We developed ultrasonic acoustic models using the finite element method with COMSOL software, and experiments were carried out to validate the simulation results. Finally, by performing the static phantoms tests, a feasibility study of ultrasonic tomography system was presented to investigate the void fraction of liquid column inside a stainless steel pipe

Development of Hot Equal Channel Angular Processing (ECAP) consolidation technique in the production of Boron Carbide(B4C)-Reinforced Aluminium Chip (AA6061)-based composite

The production of metal matrix composites (MMCs) through recycled materials is a cost-saving process. However, the improvement of the mechanical and physical properties is another challenge to be concerned. In this study, recycled aluminium 6061 (AA6061) chips reinforced with different volumetric fractions of boron carbide (B4C) were produced through hot equal channel angular processing (ECAP). Response surface methodology (RSM) was carried out to investigate the dependent response (compressive strength) with independent parameters such as different volumetric fractions (5-15%) of added contents of B4C and preheating temperature (450 – 550°C). Also, the number of passes were examined to check the effect on the mechanical and physical properties of the developed recycled AA6061/B4C composite. The results show that maximum compressive strength and hardness of recycled AA6061/B4C were 59.2 MPa and 69 HV respectively at 5% of B4C contents. Likewise, the density and number of pores increased, which were confirmed through scanning electron microscope (SEM) and atomic force microscopes (AFM) analysis. However, the number of passes enhanced the mechanical and physical properties of the recycled AA6061/B4C composite. Therefore, the maximum compressive strength and hardness achieved were 158 MPa and 74.95 HV for the 4th pass. Moreover, the physical properties of recycled AA6061/B4C composite become denser of 2.62 g/cm3 at the 1st pass and 2.67 g/cm3 for the 4th pass. Thus, it can be concluded that the B4C volumetric fraction and number of passes have a significant effect on recycled AA6061 chips

Phosphorylation of LXRα impacts atherosclerosis regression by modulating monocyte trafficking

LXRα activation in macrophages enhances regression of atherosclerotic plaques in mice by regulating genes crucial for cholesterol efflux, cell motility and inflammation. Diabetes, however, impairs plaque regression in mice. LXRα is phosphorylated at serine 198 (pS198), which affects the expression of genes controlling inflammation, lipid metabolism and cell movement. We hypothesize that LXRα function is affected by hyperglycemia through changes in LXRα pS198. Indeed, macrophages cultured in diabetes relevant high glucose versus normal glucose display alterations in LXR-dependent gene expression and increased LXRα pS198. We therefore examined the consequence of disrupting LXRα phosphorylation (S196A in mouse LXRα) during regression of atherosclerosis in normal and diabetic mice. We find that phosphorylation deficient LXRα S196A reduces macrophage retention in plaques in diabetes, which is predicted to be anti-atherogenic and enhance plaque regression. However, this favorable effect on regression is masked by increased monocyte infiltration in the plaque attributed to leukocytosis in LXRα S196A mice. RNA-seq of plaque macrophages from diabetic S196A mice shows increased expression of chemotaxis and decreased expression of cell adhesion genes, consistent with reduced macrophage retention by LXRα S196A. Thus, the non-phosphorylated form of LXRα precludes macrophage retention in the plaque. Our study provides the first evidence for a physiological role of LXRα phosphorylation in modulating atherosclerosis regression. Compounds that prevent LXRα phosphorylation or ligands that induce the conformation of non-phosphorylated LXRα may selectively enhance macrophage emigration from atherosclerotic plaques

Localizatation estimation usign the technique of multi-sequence positioning

Wireless sensor networks (WSN) have been considered as promising tools for many location dependent applications such as area surveillance, search and rescue, mobile tracking and navigation, etc. In addition, the geographic information of sensor nodes can be critical for improving network management, topology planning, packet routing and security. Although localization plays an important role in all those systems, itself is a challenging problem due to extremely limited resources available at each low-cost sensor node. This study is focusing on using a distribution-based estimation method. The reason for selecting this method because it is considered an energy saving effort comparing to costly centralized localization scheme. The scope of the estimation in localization of sensor nodes is a Multi-Sequence Positioning (MSP) method that can be applied for a large-scale network in order to achieve accurate distance estimation in sensor deployments where the source of event has a line-of-sight to all sensors. The MATLAB is the programming will be used in the study. This is conceived as an extension of existing WSN programming frameworks. The evaluation was carried based on the error resulted from location estimation scenario compared to the current localization technique of Received Signal Strength (RSS) and the Time of Arrival (TOA). The result showed that MSP showed more efficiently in short and long range as compared to TOA. However, RSS proven to perform better than MSP in long range estimation. This was reasoned to different functional related measures in which RSS is usually perceive less obstruction and shielding of satellite signals whereas MSP can be effected by cellular networks in which it limited by the cell size

CFD simulation study on the performance of a modified Ram Air Turbine (RAT) for power generation in aircrafts

The present paper aims to study the possibility of dispensing an auxiliary power unit (APU) in an aircraft powered by fossil fuels to reduce air pollution. It particularly seeks to evaluate the amount of power generated by the ram air turbine (RAT) using the novel counter-rotating technique while characterizing its optimum axial distance. The ram air turbine (RAT), which is already equipped in aircrafts, was enhanced to generate the amount of energy produced by the APU. The approach was implemented by a CRRAT system. Six airfoil profiles were tested based on 2D models and the best airfoil was chosen for implantation on the RAT and CRRAT systems. The performance of the conventional single-rotor RAT and CRRAT were analyzed using FLUENT software based on 3D models. The adopted numerical scheme was the Navier–Stokes equation with k–ω SST turbulence modeling. The dynamic mesh and user-defined function (UDF) were used to revolve the rotor turbine via wind. The results indicated that the FX63-137 airfoil profile showed a higher performance in terms of the lift-to-drag ratio compared to the other airfoils. The optimum axial distance between the two rotors was 0.087 m of the rotor diameter and the efficiency of the new CRRAT increased to almost 45% compared to the single-rotor RAT

Conventional Treatment of Surface Water Using Moringa Oleifera Seeds Extract as a Primary Coagulant

The present study involved the use of a model pilot scale water treatment plant to treat turbid surface water from a stream using processed Moringa oleifera seed with 25 % w/w oil extracted as primary coagulant. The water treatment plant was made up of four unit operations: coagulation, flocculation, sedimentation, and filtration (rapid sand filter). Test runs were carried out for three hours per run over a three-month period with turbidities ranging from 18 to 261 NTU. The turbidity, pH, and alkalinity as well as the filter head loss were measured every 30 minutes during the experimental runs. Average turbidity removal of up to 96 % at an effective doses of 20 and 30 mg/l of oil extracted M. oleifera for low ( 100 NTU) water. M. oleifera seed extract was found to have no significant effect on pH or alkalinity of the water. The residual turbidities measured during most of the test runs satisfied the Malaysian Guideline for Drinking Water Supplies.  Key Words: Moringa oleifera, primary coagulant, coagulation, pilot plant, filtration

Assessment of thermal energy storage integrated solar thermal collector system: a review

Renewable solar energy is clean, abundant and globally available although intermittent in nature, thus requires storage ability whereby the solar radiation can be utilized and store simultaneously, the excess reuse during cloudy weathers and night time when there is no solar radiation. Continuous investigations by many researchers have shown that the integration of thermal energy storage (TES) to solar collector could improve the system performance and extend their utilization beyond solar radiation hours. Several studies utilizing different energy storage materials such as phase change materials (PCM), nanomaterials, PCM nanomaterials and hybrid PCM materials have reported improved heat transfer mechanism in solar thermal collectors. However, the demerits on weight, size and space increment, leakages and poor heat transfer mechanism caused by the PCM-TES incorporation with solar thermal collectors still persists despite the several research attempts on development of new smart PCM-TES materials and their incorporation. Thus far, the current mini-review paper attempts to bridge the literature gaps on past and recent PCM-TES integration techniques used for solar thermal collector systems. In addition, the performance analysis of existing designs, material fabrications and suggested improvement are discussed in this paper

Performance evaluation of a counter-rotating vertical axis wind turbine (VAWT) on a moving train

Renewable energies are the types of energy that always exist and environmentally friendly. Wind energy is one of the renewable energy types that can reduce the mass use of fossil fuels as an alternative way to generate electricity. Practically, the Wind turbine is responsible for converting the kinetic energy as the wind act on the blades to generate electrical energy. In this study, the Savonius-type counter-rotating wind turbine has been chosen to study its aerodynamic performance on a moving train. For the simulation, the wind velocities tested start from 50 km/h until 160 km/h with 10 km/h interval between each case while investigating the performance in terms of torque and power output. The designs of the models are developed using Solidworks software and the Computational Fluid Dynamics (CFD) simulation software; ANSYS FLUENT was sued to run the simulations. The simulation results such as velocity streamlines, velocity contours, pressure contours and turbulent kinetic energy have been captured to allow the reader to observe the flow applied on the train as well as a wind turbine. The results obtained from the simulation show that the aerodynamic performance in terms of both power and torque output increases as the wind speed on the blades increases

Experimental investigation on evacuated tube solar collector using biofluid as heat transfer fluid

Bio-oil extracted from waste of different plant kernel was used as heat transfer fluid in evacuated tube solar collector. Thermal performance of the biofluids to the enhancement of the evacuated tube solar collector under varying weather conditions and experimental analysis was carried-out. Thermal analysis on the storage water tank temperature, outlet and inlet heat transfer fluid temperature, and heat gains by was studied. In addition, the biofluids thermophysical properties and degradation analysis was conducted and compared with conventional base-fluids. From the results the biofluids caused enhancement of heat gain in the collector receiver by 9.5%, 6.4% and 3.2% for moringa oleifera kernel oil (MOKO), date kernel oil (DKO) and palm kernel oil (PKO), respectively. The storage water tank temperature at night fall was 53, 49, 51 and 47oC, for the MOKO, DKO, PKO and water HTFs, respectively. The biofluids were thermal stable and with no degradation. The biofluids demonstrated potentials as heat transfer fluids in thermal applications but there are needs for more investigations on their enhancement with organically synthesized nano particles to preserve there no corrosive and toxicity nature, and experimental performance on heat exchangers after several heating cycles

Experimental investigation of double slope solar still integrated with PCM nanoadditives microencapsulated thermal energy storage

Transparent covered slope solar stills are trending but characterised with low productivity, heat losses and high energy consumption, which are setbacks in practice. In this study, double slope solar still (DSSS) integrated with PCM-TES is presented. PCM was microencapsulated with epoxy resin composite using vacuum mould-filled techniques. Conventional DSSS and DSSS-TES data collected have been compared to establish the influence of TES on productivity. Daily average temperature of the glass cover, humid air, saline water, still basin absorbern and TES cavity for the DSSS-TES attained are 65.2 ◦C, 77.5 ◦C, 82.4 ◦C, 79.5 ◦C and 68.4 ◦C, respectively. DSSSTES has yielded higher production, with 7.5 Litres of potable water daily and extension in operation period by 3 h has been achieved. In addition, condensation and evaporation rates increased with increase in production by 105%. Integration of TES with the system has reduced the heat losses while leakages from PCM nanocomposite have been prevented by microencapsulated insulator. No trace of metals, bacteria and organic contaminants has been found in desalinated water. A payback period of 0.8 year has been recorded based on all-year-round operations. Findings are in good agreement with existing models. Moreover, sensorial characteristics obtained conform to WHO standards