Multimedia environmental fate and transport model of dichlorodiphenyltrichloroethane (DDT): case study sayong river watershed

This study describes the development of a multimedia environmental fate and transport model of dichlorodiphenyltrichloroethane (DDT) at Sayong River Watershed. Based on the latest estimated DDT emission, the DDT concentrations in air, soil, water, and sediment as well as the transfer flux were simulated under the equilibrium and steady-state assumption. Model predictions suggest that soil and sediment was the dominant sink of DDT. The results showed that the model predicted was generally good agreement with field data. Compared with degradation reaction, advection outflow was more important in removal processes of DDT. Sensitivities of the model estimates to input parameters were tested. The result showed that vapour pressure (Ps), chemical solubility (Cs), and absolute temperature (T) of DDT were the most influential parameters for the model output. The model output–concentrations of DDT in multimedia environment is very important as it can be used in future for human exposure and risk assessment of organochlorine pesticides (OCPs) at Sayong River Basin

Compressibility and permeability of solidified dredged marine soils (DMS) with the addition of cement andor waste granular materials (WGM)

Dredged marine soils that obtained from dredging work were characterize as geo-waste, which is prone to be dumped rather than to be reused. This type of soil is high in compressibility and low in load bearing capacity. The engineering properties of this soft soil can be improve via soil solidification method. Cement is the common hydraulic binder used in soil solidification, were found to generate the emission of greenhouse gasses (GHG), particularly carbon dioxide (CO2) which also had affected the earth’s atmosphere. Therefore, there has been an increasing interest in using alternate pozzolanic materials such as waste granular materials (WGM) to fully or partially substituted the use of cement in soil solidification. WGM such as coal bottom ash (BA) and palm oil clinker (POC) were opted due to its pozzolanic properties. Prior to the planning of reclamation work using DMS admixed with conventional and/or alternate pozzolanic materials, the consolidation characteristics of the admixed materials must be acknowledged. Hence, the present study will examine the amount of settlement and coefficient of permeability (k) of DMS treated with cement and/or WGM in laboratory-scale experiments. Samples were prepared in various proportion in order to examine the individual effect of the cement and/or alternate pozzolanic materials on compressibility and permeability. For cement-admixed DMS, sample with 20 % of cement have significantly reduced the settlement than untreated and 10 % cemented DMS. For WGM-admixed DMS, the initial void ratio is low as compared to the untreated DMS due to the rearrangement of soil particles, which is densely packed. For cement-WGM-admixed DMS, samples of 15C50BA and 15C50POC displayed significant settlement reduction than 10C100BA, 10C100POC and untreated samples

Development and evaluation of polyherbal formulation for memory enhancement: study on its antioxidant properties and synergistic effects

Centella asiatica, Piper sarmentosum and Morinda citrifolia is well-known for their memory enhancement contribution from traditional practices as well as recent researches. However, all three herbs are utilized individually and never mixed together. The nutrient data on the synergistic effect on all three herbs remain scarce. The aims of this research project were to apply Simplex-centroid mixture design in describing the study for the effect of polyherbal formulation on antioxidants properties and its synergistic effects. Based on results obtained, there was a significant difference in antioxidant properties of the polyherbal formulation. The results show the polyherbal formulation 3 and 13 (M. citrifolia only) has the highest antioxidant capacity when being tested with total phenolic content (TPC) (210.10 and 209.12 μg GAE/mL respectively) and 2,2-diphenyl-1- picrylhydrazyl (DPPH) (42.94 and 37.77%) assays. Contradict to this result, the highest in total flavonoid content (TFC) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) for describing antioxidant properties are formulations 1 and 11 (C. asiatica only). The TPC for formulation 1 and 11 are 479.8 μg RE/mL and 470 μg RE/mL respectively while ABTS radical inhibition for formulation 1 and 11 are 64.53% and 60% respectively. For ferric reducing ability of plasma (FRAP) assay, formulation 7 (2.11 μg FSE/mL) is the highest which have 1:1:1 ratio of each herb. In addition, TPC, TFC, and DPPH assays showed high antioxidant activities when only single herbs were added into the formulation. Meanwhile, ABTS and FRAP are prone to binary polyherbal formulation. Hence, this study showed an antagonism effect instead of synergistic effect since single formulation exhibited the highest for TPC, TFC and DPPH. All tests gave the lowest antioxidant properties when the mix was ternary polyherbal formulation

Cu-Mn and Cu-Ce supported over agro-based carbons: characteristics and NOx adsorption study

As there is an urgent need for cheaper and sustainable resources for selective catalytic reduction catalyst, this study determined the potential, in terms of the catalyst characteristics and NOx adsorption, of coconut shell (CSAC) and palm kernel shell activated carbons (PSAC) to be used as precursors for the catalyst in a low-temperature flue gas denitrification system. The carbons were impregnated with bimetallic catalysts –copper-manganese (Cu-Mn) and copper-cerium (Cu-Ce) – before calcined at low temperature. The produced coconut shell catalysts (CuMn/CS and CuCe/CS) and palm kernel shell catalysts (CuMn/PS and CuCe/PS) were then characterized using a nitrogen adsorption-desorption test, Fourier-Transform infra-red, x-ray fluorescence, x-ray diffraction and hydrogen temperature-programmed reduction. The removal of NOx was also studied for all catalysts in a fixed-bed reactor. It was found that CuMn/CS gave the highest NOx removal. CuMn/CS had high pore volume, good Cu-Mn crystallinity, highmetal loading and dispersion, high copper reduction activity at the operating temperature, and rich in ketone and amine surface functional groups. It is then concluded that the coconut shell has the potential to be developed as a good SCR catalyst via impregnation with Cu-Mn

CONCENTRIC TUBE-FOULING RIG FOR INVESTIGATION OF FOULING DEPOSIT FORMATION FROM PASTEURISER OF VISCOUS FOOD LIQUID

This paper reports the work on developing concentric tube-fouling rig, a new fouling deposit monitoring device. This device can detect and quantify the level of fouling deposit formation. It can also functioning as sampler for fouling deposit study, which can be attached at any food processing equipment. The design is initiated with conceptual design. The rig is designed with inner diameter of 7 cm and with tube length of 37 cm. A spiral insert with 34.5 cm length and with 5.4 cm diameter is fitted inside the tube to ensure the fluid flows around the tube. In this work, the rig is attached to the lab-scale concentric tube-pasteurizer to test its effectiveness and to collect a fouling sample after pasteurization of pink guava puree. Temperature changes are recorded during the pasteurization and the data is used to plot the heat transfer profile. Thickness of the fouling deposit is also measured. The trends for thickness, heat resistance profile and heat transfer profile for concentric tube-fouling rig matched the trends obtained from lab-scale concentric tube-pasteurizer very well. The findings from this work have shown a good potential of this rig however there is a limitation with spiral insert, which is discussed in this paper

Flow analysis of piston head geometry for direct injection spark ignition engine

Constructors of gasoline engines face higher and higher requirements as regards to ecological issues, and increase in engine efficiency at simultaneous decrease in fuel consumption. Satisfying these requirements is possible by the recognition of the phenomena occurred inside engine cylinder, the choice of suitable optimal parameters of fuel injection process, and the determination of geometrical shapes of the combustion chamber and piston head. The aim of this study is to simulate flow in Fuel Direct-Injection engine with different geometrical shapes of piston head. Designing piston head shapes was done by referring to existing motorcycle, Demak 200cc-single cylinder using SolidWork and ANSYS software. The parameter investigated are shallow and deep bowl design of piston head. In term of fuel distribution throughout the combustion chamber, engine model that has deeper bowl (Model 2) shows better fuel distribution than model of shallow bowl as it manages to direct the fuel injected towards the location of spark plug. Total kinetic energy of Model 2 is about 20% higher than Model 1. Therefore, engine with deeper bowl is chose as the best model between the two models as it can create a richer mixture around the spark plug

Effect of boric acid mixture as solid lubricant towards machining processes

Milling is widely used metal removal process in manufacturing industry that involves generation of high cutting forces and temperature. Lubricants become important to reduce the cutting force and temperature for better machining processes and performances. Conventional cutting fluid has some limitations. The applications of conventional cutting fluid create some techno-environmental problems like environmental pollution, biological problems to operators and water pollution. Application of solid lubricant in milling has proved to be a feasible alternative to the conventional cutting fluids. The present work investigates the effect of boric acid as solid lubricant towards machining performances such as tool wear and surface roughness. The results indicate that boric acid can improve the cutting processes and performance compared to conventional cutting fluid