Applied Mechanics and Materials Vols. 446-447

Abstract: This paper proposed an energy-saving system which combination solar collectors for heating water system with heat pipe heat exchanger to recover kitchen waste heat. Its working principle is using heat pipe exchangers exhaust heat to warm the cold water from water storage tank, and during the day, take advantage of solar collectors to help heat pipe heat exchanger heating the water. In this design, the heat exchanger tank and the heat storage tank arranged independently, water tank associated control system was provided with automatic temperature regulator to control the opening and stopping of the pump. This system made full use of kitchen waste heat and solar to meet the kitchen cooking and cleaning process hot water supply needs.

Abstract: In this study, a new kind of photocatalysts was prepared by titanium dioxide, sodium dodecyl sulfate and copper. It was used to improve the biodegradability of textile wastewater under solar light. The effect of light intensity, dissolved oxygen and wastewater hydraulic remain time on the biodegradability improvement were researched. Experiments show that when the light intensity, DO and HRT are 2.1mW/cm², 2.37mg/L and 3h, respectively, the B/C value of textile wastewater increases from 0.11 to 0.37, and DHA value increases from 3.72TF/(ml·h) to 22.68μgTF/(ml·h). Photocatalysis reactor combined with sequencing batch reactor was used to further treat textile wastewater. The results show that COD and BOD₅ decline to 71mg/L and 18mg/L, respectively.

Abstract: In this work, we report rice husk ash prepared via a thermal treatment process used as oil sorbents for oil spill cleanup. The oil sorbent with highly porous structures shows a crude oil sorption capacity of 15 g/g. The rice husk ash was studied on the basis of phase composition, microstructure and morphology using X-ray diffraction analysis, FTIR spectrometry and scanning electron microscopy (SEM). The results of the SEM studies strongly indicate that thermal treatment is a suitable method to improve structure of husk particles regarding porosity compared to virgin samples.

Abstract: In the paper ways of using rubber crumb from worn tires were investigated. Possibilities of preparing Rubber-Bitumen Compounds (RBC) based rubber crumb (RC) from worn tires were studied experimentally. The physico-mechanical characteristics of paving bitumen BND 60/90 modified with rubber crumb and spent engine oil. The structure of rubber crumb was characterized by optical microscopy. Physico-mechanical characteristics of RBC were detrminated by standard methods. It is established that the quantity of entered binders depending on physical and chemical conditions, which was optimal composition of rubber-oil at a ratio of 1:1 and 3:2 and introduction to bitumen in amount of 15-25 wt.%.

Abstract: The degree of heavy-metal pollution of different district in city area is discussed by improved Nemerow model and further topographic maps are drawn .From the improved Nemerow model, the Nemerow integrated pollution index is determined . The main reason of pollution is found according to weight, then the corresponding heavy-metal pollution things portion in the overall district is computed by using the model . The element that corresponds the maximum weight is found .And it proves that the heavy-metal pollution element Hg is the main pollution reason .The pollution source is determined by heavy metal spreading features using transfer function theory. Thinking of the main pollution elements as the researched object ,the spreading features are analized using transfer function characteristics. And the spreading process is described using flow chart.

Abstract: Free fatty acid (FFA) in mixed crude palm oil (MCPO) must be reduced to less than 1 wt.% or 2 mgKOH.g^-1 of acid value by the acid-catalyzed esterification process when the base-catalyzed transesterification was used to produce the biodiesel for the two-stage process. This study was to investigate the effects of acid catalyst types: sulfuric acid (H₂SO₄), phosphoric acid (H₃PO₄), and hydrochloric acid (HCL) at 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 vol.% of acid catalyst concentration on the reduction of acid value in MCPO by the continuous static mixer. Results indicated that H₂SO₄ has the most significant variable affecting the acid value in MCPO. The acid catalyst concentration of 1.0 and 1.5 vol.% H₂SO₄ can reduce the acid value to less than 2 mgKOH.g^-1 with 15 vol.% of methanol and 5-meter in the length of static mixer, while both H₃PO₄ and HCL could not reduce the acid value was reduced to less than 2 mgKOH.g^-1. Moreover, the results clearly indicated that HCL has the lowest significance effect on the acid value reduction in MCPO by the esterification reaction.

Abstract: Analytical results are considered the factors of suspended sediment concentration, fall velocity, dimensionless shear stress, transportation rate and stream discharge. As a result of suspended sediments of Loei, Huang and Mekong River, fine particles account for the applicability in sediment deposits. Floating suspended sediments explicit more clay minerals than suspended sediments. Suspended sediment concentration (SSC) in the estuarine of Loei River and Huang River are moderately less than Mekong River. Flow directions of the interconnected rivers to the mainstream-Mekong River lead to the quantity of SSC. Sediment concentrations attain to the dynamic response. Dimensionless shear stress relates to shear velocity, geometry and grain size of particles, and difference of flow velocity. This shear stress is directly comparative to flow velocity and clay mineral concentrations. The transport rate involves in the flow velocity, SSC and depth of the river. Moreover, stream discharge can be presumed by the geometry of the river and topography of sampling locations.

Abstract: This paper introduced an approach that a novel tubular membrane was used to separate oil/water emulsion from kitchen wastewater. Separation capability of the tubular membrane and its regeneration performance after repeatedly membrane cleaning were investigated. The results showed that oil removal was up to 99.8% and the concentration of filtrate was less than 20 mg/L, which met the requirement for discharge. The suitable operating pressure and treatment concentration is 0.10 MPa and less 15 g/L respectably, the best way to clean membrane is washing it using clean water every 20 min and membrane flux recovery value of 99% or more was achieved. Results above suggested that the membrane had excellent performances for oil/water emulsion treatment and good application prospect.

Abstract: The thickness of multi-layer absorbing material is optimized to obtain lower electromagnetic reflection coefficient by using particle swarm optimization (PSO) algorithm in this paper. Two examples are employed to validate the excellent performance of PSO. The results show that the reflection coefficient of absorbing material is less than-20 dB over the bandwidth of 2GHz ~ 18GHz, less than-25 dB over the narrowband of 9 GHz ~ 11GHz, less than-30 dB during the bandwidth of 9.5 GHz~10.5 GHz. It also shows that the minimum value approaches to-48 dB in a certain range.

Abstract: Solar Parabolic Trough collectors are commonly used to harness the solar power for power generating applications involving high temperatures. In the given paper study we have made use of the SolTrace software which uses the Monte Carlo algorithm for finding out the radiation received on the absorber tube of the collector. The computational study was performed taking into account the solar radiation received at Vellore city in India (12.92^oN, 79.13^oE) as on 16^th February 2013. Further a 3D model of the absorber tube used in the parabolic trough collector was created and meshed with the help of the Ansys Gambit software. The absorber tube which we considered for our study is made up of Stainless Steel AISI 302 material. The meshed model so created was then exported to the Ansys Fluent 6.3 software and simulations were performed for different mass flow rates of the fluid. The fluid which we used in the computational analysis study is Therminol 55. The temperature differences for different mass flow rates of the liquid passing through the absorber tube were found out and based on the temperature rise contours plots so obtained, we have plotted the surface heat transfer coefficient for the absorber tube. We also found out the static temperature contour plot for the fluid flowing through the given absorber tube taking into account the heat flux acting on the absorber tube due to the hourly and daily average solar radiation.