Characterizations of waste soil of open dumping area

The heterogeneous content of waste soil from dumping area are complicated to characterize and classified. The total number of dumping area has been increase with the increase of population in Malaysia. The content of waste dumped at the dumping area is important to analyze because the degradation process change with time. Three categories have been proposed in this paper namely Category I: Soil like and non-soil like, Category II: Waste types and Category III: Waste or Soil. The waste soil are analyzed based on its geotechnical properties such as particle size distribution, specific gravity, shear strength, settlement displacement, compaction curve and triaxial strength and mineral compositions. Two types of representatives samples were collected, one from dumping area at Sri Hartamas and one from non-dumping area located at Bukit Chuping area. The dumping area samples were named as waste soil. It can be concluded that the waste soil consists of high friction angle which range from 11 degrees to 38 degrees, settlement displacement of 0.5 mm/min to 3.5 mm/min for loading of 3 kg, 5kg and 7 kg of applied normal loads. The compaction curve of waste soil has the maximum dry density of 1489 kg/m3 to 1600 kg/m3 and the optimum moisture content of between 27% to 30%. These parameters are important in determining the long-term settlement of the open dumping area

Long-term settlement prediction at open dumping area using Hossein and Gabr method for new development

In Malaysia, the most common method of disposal is landfill/open dumping. The soil at the dumping area are mixed with waste and soil. Thus, it was called as waste soil. Due to its heterogeneity properties, waste soil has a different settlement rate because different types of waste tends to settle differently. The Hussein and Gabr model which used empirical model was proposed to compute the long-term settlement. This Hussein and Gabr model is one of the soil settlement model that can be used to predict the long-term settlement at the dumping area. The model relates between the compression index and the time factor. The time factor are t1, t2, t3 and t4. The compression index is Cα1=compression index and Cβ is biodegradation index. The duration for initial compression, the compression, the biological compression and time creep are included in the model. The sample of waste soil is taken from closed dumping area in Lukut, Negeri Sembilan with the height of waste approximately 1 to 3 meters. The sample is tested using consolidation test for determining the geotechnical parameters and compressibility index. Based on the Hossein and Gabr model, the predicted long-term settlement for 20 years (ΔH) for the waste height of 1 to 3 meters are 0.21m, 0.42m and 0.63m respectively and are below the percentages of proposed maximum settlement for waste soil which is acceptable for new development to takes place.. The types of deep or shallow foundation are proposed based on the predicted settlement. The abandoned open dumping area can now be reused for the new development after the long-term settlement are predicted and some of the precaution measures has been taken as a safety measures

Effect of Ag nanoparticles seeding on the properties of silica spheres

In this study, the effect of seed-recrystallization on the Ag deposition onto silica sphere surfaces has been investigated. It was found that increasing the seed-recrystallization cycles resulted in higher atomic deposition at ca. 84% coverage of silica surfaces with the same mole ratio of Ag precursor characterized by the Ag/Si atomic ratio obtained by XPS analyses. The addition of straight-chain palm oil derived fatty alcohols (PODFA) in the sol-gel prior to seed-recrystallization aided the deposition of Ag. Thus, PODFA play the role of nonsurfactant surface modification agent to produce Ag-silica nanocomposite. Structural analyses showed that the resulting Ag nanocrystallines having a face centre cubic structure and particle size of 5–20 nm were deposited homogeneously on silica spheres. Chemical state analyses from XPS indicated that the increasing number of seed repetition process increased the seeding of Ag nanoparticles on silica surface with the same molar of Ag atoms. XPS spectra at O1s orbital elucidated that the binding energy of three oxides components were determined at ca. 533.8 eV (Si-O-H), 532.8 eV (Si-O-Si) and 530.8 eV (Si-O-Ag), respectively. The high sensitivity of surface plasmon resonance observed in the nanocomposites prepared in this study are useful in optical applications

Nonsurfactant route of fatty alcohols decomposition for templating of mesoporous silica

Mesoporous silica with wormhole-like channel networks were successfully prepared in a direct synthesis method by a modified two-step base-acid catalyzed nonsurfactant carbon templating route at room temperature. This new method allows direct decomposition of palm oil derived fatty alcohols onto silica sources generating the required carbon template in situ to induce mesoporosity. Carbon templating using palm oil-derived fatty alcohols are renewable and environmental friendly. Furthermore, this method was carried out in a simple manner and the porosity of the resulting materials could be controlled successfully. The resulting materials had high surface area of 505 m(2)/g and pore volume of 1.4 mL/g, respectively. The median pore diameter estimated by the BJH method was at ca. 7.8 nm to 13 nm. Moreover, pH functionalized mesoporous silica materials exhibited stable absorbances for more than ten cycles at ca. 560 mu. (C) 2007 Elsevier Inc. All rights reserved

Experimental and SPH study of cold spray impact on similar and dissimilar metals

In this study, the critical, maximum and optimum velocity of a single cold sprayed (CS) particle is estimated using the smoothed particle hydrodynamics (SPH) method by evaluating the impact shape coefficient of restitution, as well as the rebound and deposit energy ratio. The contact surfaces of the particle and the substrate are modelled as intersurface forces using the Dugdale– Barenblatt cohesive zone model. The application of SPH allows the simulation of the CS process without the use of mesh, thereby avoiding the disadvantages of the traditional numerical method in handling large deformations and tracing moving interfaces. The impact of CS particles is simulated using various powder and substrate materials. The influence of the materials on the optimum velocity and the coating quality is discussed. The reliability of the model is verified with CS experiments

Microcrack pattern propagations and rock quality designation of Batu Caves limestone

Microcrack pattern of limestone with various grade of natural weathering were studied to examine the microcrack initiation and propagations in relation to Rock Quality Designation (RQD) and shear strength parameters such as shear stress and normal stress. The degree of natural weathering were determined using Schmidt hammer test and it was found that as the weathering grade increased from grade I to grade IV, the microcrack length changed from ca. 500 μm to a longer length of ca. 800 μm. The increased in microcrack length were coupled with the increased in width of the cracks as observed using Scanning Electron Microscope (SEM). Furthermore, it was suggested that the microcrack length of limestone is inversely proportional to RQD value with confidence level of 60%. However, the microcrack length of limestone was observed to be directly proportional with shear stress and normal stress with confidence level of 95% and 99% respectively

Pages: 24-30 Aust

This paper presents the development works of using a 355nm ultraviolet (UV) laser diode ablation process for low-k/ULK semiconductor device. The effects of laser micromachining parameters, i.e. laser power, laser frequency, feed speed, and defocus amount were investigated. The laser processed die samples were thoroughly inspected and characterized, included the die edge/side grooving quality, the grooving shape/profile, and the grooving depth. High power optical microscopy, scanning electron microscopy (SEM), and focused ion beam (FIB) are the inspection tools/methods used in this study. Package reliability and stressing were carried out to confirm the robustness of the laser grooving process parameter and condition in mass production environment. The dicing defects caused by the laser were validated by using failure analysis. The advantages and limitations of laser grooving process were also discussed. It is shown that, laser grooving is possibly one of the best solutions to choose for dicing quality and throughput improvements for low-k/ULK wafer dicing. Laser process is feasible, much faster, and simple process compared to the conventional blade dicing process

The Role of Deposition Temperature in the Photovoltaic Properties of RF-Sputtered CdSe Thin Films

Cadmium selenide (CdSe) thin films were grown on borosilicate glass substrates using the RF magnetron sputtering method. In this study, CdSe thin film was deposited at a deposition temperature in the range of 25 °C to 400 °C. The influence of deposition or growth temperature on the structural, morphological, and opto-electrical properties of CdSe films was investigated elaborately to achieve a good-quality window layer for solar-cell applications. The crystal structure, surface morphology, and opto-electrical characteristics of sputtered CdSe films were determined using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), UV–Vis spectrophotometry, and Hall effect measurement, respectively. The XRD results revealed the polycrystalline nature of CdSe, with a hexagonal structure having a strong preferential orientation toward the (002) plane. As evident from the FESEM images, the average grain size and surface morphology of the films were dependent on deposition temperatures. The carrier concentration was obtained as 1014 cm−3. The band gap in the range of 1.65–1.79 eV was found. The explored results suggested that sputtered CdSe thin film deposited at 300 °C has the potential to be used as a window layer in solar cells