Shinichi Ookawara

Improved WO3 photocatalytic efficiency using ZrO2 and Ru for the degradation of carbofuran and ampicillin.

The photocatalytic degradation of carbofuran (pesticide) and ampicillin (pharmaceutical) using synthesized WO3/ZrO2 nanoparticles under simulated solar light was investigated. Transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectra analyses were used to characterize the prepared catalysts. The optimum ratio of WO3 to ZrO2 was determined to be 1:1 for the degradation of both contaminants. The degradation of carbofuran and ampicillin by WO3/ZrO2 after 240 min of irradiation was 100% and 96%, respectively. Ruthenium (Ru) was employed as an additive to WO3/ZrO2 to enhance the photocatalytic degradation rate. Ru/WO3/ZrO2 exhibited faster degradation rates than WO3/ZrO2. Furthermore, 100% and 97% degradation of carbofuran and ampicillin, respectively, was achieved using Ru/WO3/ZrO2 after 180 min of irradiation. The durability of the catalyst was investigated by reusing the same suspended catalyst, which achieved 92% of its initial efficiency. The photocatalytic degradation of ampicillin and carbofuran followed pseudo-first order kinetics according to the Langmuir-Hinshelwood model.

Mathematical modeling of bio-hydrogen production from starch wastewater via up-flow anaerobic staged reactor.

AbstractHydrogen production from starch wastewater industry via up-flow anaerobic staged reactor was investigated. The reactor was operated at an average organic loading rate of 13.17 ± 8.35 g COD/L d and hydraulic retention time of 8 h. The reactor achieved chemical oxygen demand (COD) and carbohydrate removal efficiencies of 84 and 92%, respectively. The total volatile fatty acids increased from 58.5 ± 30.0 (influent) to 235.6 ± 190.8 mg/L in the treated effluent, indicating that acidogenesis bacteria were dominant in the reactor. The system achieved maximum hydrogen production rate (HPR) and hydrogen yield of 2.48 L H2/d and 8.8 mL H2/g CODremoved, respectively. Simulated model tracks the experimental data with a correlation coefficient (R2 = 0.893). Maximum substrate utilization rate (μmax,s) and maximum volumetric HPR (μmax,h) were calculated at different food to micro-organisms (F/M) ratios of 0.15, 0.31, 0.46, 0.62, and 0.93 g COD/g VSS. Results showed that μmax,s increased to −0.76 g COD/L h at F/...

Effect of dust deposition on performance of thin film photovoltaic module in harsh humid climate

This study investigated experimentally the effect of air born suspend matters deposition on PV module located in harsh climate close to the sea. The experimental measurements are carried out under outdoor conditions in Alexandria, Egypt to identify the module performance degradation as a function of time as well as the time schedule for module surface cleaning. However, as the sea is nearby its a source for nocturnal condensate on module surface. The experiments were conducted during period from 13 March to 17 April, 2013. The results indicated that the dust accumulation on the module surface has a significant impact on PV module output power. As the dust deposition density increased from 0 to 0.36 mg cm-2, the corresponding reduction of PV output efficiency as well as short circuit current Isc are degraded by 17.71%. Conversely, the reduction of open circuit voltage was insignificant where the maximum reduction of Voc from 100% to 97.86 of the clean module value. The average degradation of power and efficiency during the entire period of work (30 days) is 9.86%. Also the results show that the dust effect on thin film PV modules becomes most significant in cloudy weather day rather than clear day and the degradation in performance reaches about 16.01% in cloudy day.

Performance enhancement of vapor compression cycle using nano materials

The performance of a vapor compression cycle with nanomaterials additives to the working fluid is investigated theoretically and experimentally. Polyolester (POE) oil with AL2O3 nanomaterials additives is used to enhance the performance in the vapor compression cycle with R-143a refrigerant. The stability of nanofluid was first tested by using sedimentation test. The performance of cycle with the nanomaterials was then studied using energy consumption and freezing capacity tests. Theoretical analysis shows that the heat transfer coefficient in the evaporator with nanorefrigerant increases by 50%. Moreover, exergy loss decreases by 28 % when nanorefrigerant is used .The experimental results indicate that R-134a and Polyolester (POE) oil with AL2O3 nanoparticles enhance the vapor compression cycle performance by 10.5 % with 13.5 % lees energy consumption. These results were obtained with 0.1% mass fraction of nano-lubricant oil.

PERFORMANCE ASSESSMENT OF TURBOJET ENGINE OPERATED WITH ALTERNATIVE BIODIESEL

This study investigated experimentally the performance of turbojet engine fueled by biodiesel obtained from different feedstocks. The engine is equipped with measuring sensors for pressure, temperature, thrust, shaft speed in addition to flow meter, data acquisition system and a control unit. The results of the effect of biodiesel fuel type and its blends on turbojet engine performance are presented. Three biodiesel fuels which are Cotton methyl ester (CTME), Corn methyl ester (CRME) and Sunflower methyl ester (SME) and their blends of B10, B20 and B50 (10%, 20% and 50% biodiesel/Jet A1 by volume) are used and compared with the engine recommended fuel (Jet A1). Moreover, in this study, the Biodiesel fuel is produced through transesterification process in which the triglyceride (oil) reacts with alcohol (methanol) to form the mono-alkyl ester (biodiesel) and glycerol. Physical and chemical properties of all produced and tested fuels are measured. The results clearly indicate that the produced biodiesel fuels have a higher density, kinematic viscosity, than JetA-1 fuel, while, the calorific value of biodiesel fuels is very close to JetA-1 fuel. Moreover, JetA-1 fuel has higher sulfur content than other biodiesel fuels. Also, the experimental results show that Engine speed for the cases of using biodiesel fuels is lower than JetA-1 fuel at the same fuel throttle valve opening. Moreover, the Biodiesel fuels have a lower fuel volume flow rate compared to JetA-1 at the same throttle valve opening that lead to decrease the engine static thrust as well as lower value of TSFC.

Mass transfer time in a deep bubble bed

In this study, a new modified mass transfer time due to Fan and Tsuchiya (1990) is found applicable for the deep bubble bed examined and physcial interpretation is presented for the difference between characteristic times.

Experimental Study of Alumina Nanofluids Effects on Thermal Performance Efficiency of Flat Plate Solar Collectors

Flat-plate solar collectors (FPSC) heaters are widely utilized for heating water in residential buildings and other commercial and industrial applications. The main disadvantage of solar water heater is their low efficiency. Improving the thermal characteristics of the working fluid in solar water heater can dramatically increase its thermal efficiency. The aim of the present experimental investigation is to study the effect of using Alumina nanofluids as a working fluid for the solar water heater on its efficiency. Triton X-100 (Iso-Octyl Phenoxy Polyethxy Ethanol) was used as a surfactant and its stability and aggregation of the suspension was investigated. Outdoor experiments have been carried out in New Borg El-Arab city, Alexandria, Egypt according to ASHRAE Standard 86-93. Two similar water heaters systems using pure water and the nanofluids were tested at the same time, locations and similar conditions. The results showed that using nanofluid of 0.15% Alumina particles improves the FPSC thermal efficiency by 18%. More than concentration of surfactant were tested and the results showed that more stable nanofluid could be prepared to employ suitable surfactant concentration and by sophisticating preparation protoco

Steady State Permeate Flux Estimation in Cross-Flow Ultrafiltration of Protein Solution

In the membrane separation process, the cross-flow configuration in which the fluid flows parallel to the membrane is widely utilized. Due to the shear stress exerted by the tangential feed flow, the accumulation of the retained species in the membrane is reduced, and the nearly steady state operation can be attained. The determination of steady state permeate flux is significant in the design and optimization problem. Several mechanisms of transport phenomena have been proposed to estimate the steady state permeate flux such as concentration polarization and Brownian diffusion, shear-induced diffusion, inertial lift, and surface transport. Another approach is using dimensional analysis to give the correlation equation with the operating condition instead of a deep focus on mechanism. In this study, we apply the model proposed in our previous study to predict the steady state permeate flux from the experimental data. After that, a new method using dimensional analysis is also developed to predict the steady state permeate flux from the operating conditions such as the trans-membrane pressure, the feed flow rate, and the feed volume fraction in a wide range. The correlation equation provides a good estimation of the experimental results.

Effect of diffuser configuration on the flow field pattern inside wind concentrator

In this paper, the effect of the diverging part (diffuser) configuration on the flow field pattern inside wind concentrator is investigated by computational fluid dynamics (CFD) simulations. Diffusers with different diameter ratio, lengths and profiles are examined to estimate the optimum location of the turbine rotor inside wind concentrator and to attain minimum wake losses. The obtained results show that the optimum diverging diameter ratio (d₃/d₂) is 2, and diverging length to cylinder diameter ratio (l₃/d₂) is 1.33, respectively. The optimal diffuser shape is the convex that has a radius of curvature (R₂/d₂) of 2.293. The corresponding wind speed-up ratio (acceleration factor) K (= U_x/U_o) equals 2.33 at a corresponding axial distance measured from wind concentrator inlet, (x/d₂) equals 1.34 which is the optimum location of the wind turbine rotor.

A Model for Transport Phenomena in a Cross-Flow Ultrafiltration Module with Microchannels

Cross-flow ultrafiltration of macromolecular solutions in a module with microchannels is expected to have the advantages of fast diffusion from the membrane surface and a high ratio of membrane surface area to feed liquid volume. Cross-flow ultrafiltration modules with microchannels are expected to be used for separation and refining and as membrane reactors in microchemical processes. Though these modules can be applied as a separator connected with a micro-channel reactor or a membrane reactor, there have been few papers on their performance. The purpose of this study was to clarify the relationship between operational conditions and performance of cross-flow ultrafiltration devices with microchannels. In this study, Poly Vinyl Pyrrolidone (PVP) aqueous solution was used as a model solute of macromolecules such as enzymes. Cross-flow ultrafiltration experiments were carried out under constant pressure conditions, varying other operational conditions. The permeate flux decreased in the beginning of each experiment. After enough time passed, the permeate flux reached a constant value. The performance of the module was discussed based on the constant values of the flux. It was observed that the permeate flux increased with increasing transmembrane pressure (TMP) and feed flow rate, and decreased with an increase of feed liquid concentration. A model of the transport phenomena in the feed liquid side channel and the permeation through the membrane was developed based on the concentration and velocity distributions in the feed side channel. The experimental results were compared with those based on the model and the performance of the ultrafiltration module is discussed.