Papers by Keyword: Migration

Abstract: In Malaysia, there are some accumulation of sugar refinery byproducts with a lot of this material not being utilized in a productive manner, while, these byproducts had the great potential when mixed into agricultural soils as organic fertilizer with many of benefits that can improve soil health, and sustainable agronomic productivity. Pressmud or known as filter cake is a by-product of sugar industry and for every 100 tons of sugarcane crushed about 3 tons of pressmud cake is left behind as by-product. This studies carried out on this material have not properly summarized their characteristics properties that they can be used as aid for future works. Data from tests involving pressmud samples from Malayan Sugar Manufacturing (MSM) Prai Berhad, Penang which was part of a larger collection was analyzed. The physicochemical properties of pressmud characterization as well as leaching test were carried out. The physicochemical and engineering properties involved compaction behavior, permeability, cation exchange capacity (CEC), compressive stress test and its surface functional groups. The leaching test method included batch equilibrium test and column test. The optimum value of water content in pressmud was determined in the compaction test. It was found out that pressmud has higher optimum water content value was observed. The permeability test of pressmud gave value in ranges of 1.84 x 10^-5 cm/s. The Cation Exchange Capacity (CEC) of pressmud indicated value in the range of 99 to 101 meq/100 g. The high cation exchange capacity indicated that pressmud was believed to be primarily responsible for sorption of metal ions. It can be concluded that pressmud having the capability to remove heavy metals through CEC process. Pressmud also showed higher compressive strength value. Batch equilibrium test glaringly showed that pressmud have the capability to remove from 53.6%-93.8% metal removed from metal solutions for Chromium (Cr), Copper (Cu), Manganese (Mn), Nickle (Ni), Lead (Pb) and Zinc (Zn). From the result of column test, pressmud alone was able to retain efficiently all the heavy metals as these metals did not reach 1 (relative concentration) until 10 pore volume (PV.) indicating that pressmud was a good mixture material as it can assist in adsorption of heavy metals. Based on the characterization study, removal efficiency and column test, pressmud has great potentiality to be used as an additional material in soil amendments to enhance soil fertility and strength ability.

Abstract: Municipal solid waste landfills are major sources of environmental pollution. This study evaluated heavy metal concentrations in soils around Pulau Burung Landfill, Penang, Malaysia, to determine the pollution potential of a landfill. Soil samples were collected at depths of 0–20 cm (top), 20–40 cm (center) and 40–60 cm (bottom) around the landfill and at a control site and characterized for various properties and concentrations of Lead (Pb) and Zinc (Zn). Samples of daily soil cover, collected from the same sites where soil samples were collected, were also analyzed for several of heavy metals analysis. The soils were silty sand, mostly acidic (4.45) with low organic matter content (0.41%) and cation exchange capacity (3.15-3.19 meq/100 g). Other basic physico-chemical and adsorption properties were conducted on soil indicated that soil alone is not effective to be used in the landfill to support the pollutant for a long time. Heavy metals concentrations (as background data) in the soils followed the order Iron (Fe) > Zinc (Zn) > Manganese (Mn) > Lead (Pb) > Arsenic (As) > Chromium (Cr) > Cadmium (Cd) > Copper (Cu) > Nickle (Ni) with samples from around the landfill having higher concentrations especially Iron, (Fe) and Zinc, (Zn). For soil profile contribution, heavy metal enrichment was highest at a depth of 40–60 cm. In short, soil alone cannot retain and minimize the migration of heavy metals in landfill based on the results of this study including removal efficiency test. Monitoring of environments around active landfills needs to be ongoing to mitigate negative impacts on humans and the environment.

Abstract: Based on the interaction of solid and liquid phases in metallic systems, the paper deals with the properties of grain boundary propagation (migration) in solid-state alloys. Using the effect of surface solid-state dispersion enables to obtain composite materials and brazed joints with a required set of physical and mechanical properties. For the first time, the authors investigate the features of boundary migration in type II systems, in which, in accordance with the thermodynamic criterion σ_ss< 2 σ_SL, the grain-boundary propagation is not basically allowed.

Abstract: The FTIR spectroscopy method was used to investigate the changes in palm, sunflower and rapeseed oil at thermal influence up to 195°C, and also in contact with polyethylene terephthalate (PET) and polyamide (PA-6) film for 1 hour 50 minutes. It has been found that heating the oil to 195°C in contact with PET and PA-6 film does not lead to any noticeable changes in the IK oil absorption spectra. Peaks characteristic of polymers (in areas of 1535 and 1634 cm^-1), are not observed.

Abstract: The NO anneal has been shown to effectively remove 99% of defects in SiC based devices. However, the details of interactions of NO molecules with amorphous (a)-SiO₂ and SiC/SiO₂ interface are still poorly understood. We use DFT simulations to investigate the NO incorporation energies in a-SiO₂, and how these are affected by the steric environment. The results explain the ease with which NO molecules incorporate into a-SiO₂ and give an insight into the diffusion paths they take during annealing. We highlight the importance of exhaustive sampling for exploring NO diffusion pathways.

Abstract: The migration of antioxidants including α-tocopherol (AT) and butylated hydroxytoluene (BHT) from durian rind cellulose reinforced poly (lactic acid) (PLA) biocomposites into 95% ethanol and its effect on stability of edible oil were investigated. The biocomposites materials containing 5% w/w antioxidant were compounded using Brabender internal mixer followed by hot press machine and were then placed in contact with 95% ethanol at 27°C and 37°C. Released antioxidants were measured by UV-spectroscopy for 45 days. The material containing BHT generated the faster release than α-tocopherol. Both of antioxidants released at 37°C faster than 27°C. The faster release of antioxidant from each condition resulting inhibition of lipid oxidation. Oxidative stability of edible oil was investigated by monitoring of peroxide value (PV) of edible oil. The result was found that edible oil contact with biocompotises containing BHT showed lower PV compared to α-tocopherol during storage. Therefore, it can be summarized that BHT is suitable antioxidant to be used in active packaging application for edible oil.

Abstract: The paper summarizes utilization of nanoparticles (NP) in concrete for enhancing its mechanical, transport or other properties. The first part is devoted to review of NPs used in fresh concrete mixtures that have been reported previously in the literature while the second part shows original results from utilization of nanoparticles as healing agents for reparing of existing concrete structures. In the second case, nanoparticles are delivered to concrete via electrokinetic principle by using their surface charge provided in colloidal solutions. Particles are transported in the pore liquid of concrete due to electric field applied between the concrete surface and steel reinforcement. In this way, distressed concrete can be repaired, cracks sealed and risk of corrosion diminished. The injection of NPs can be complemented with extraction of chlorides that are the main deteriorating chemicals in reinforced concrete structures. Finally, the paper shows a framework developed for the electrokinetic transport of ionic species in concrete applied to chloride extraction from concrete and how it can be modified also for transport of nanoparticles.

Abstract: The evaluation of the necessary duration of a molecular dynamics experiment for the calculation of the diffusion coefficient at migration of different point defects in Ni (vacancy, bivacancy, self-interstitial atom, hydrogen atom) is held in the present work. It is shown that at the temperature higher than 0.6 of melting point is usually enough the simulation during of 100 ps for this. When calculating of the diffusion coefficient of impurity in the metal crystal, for example, of hydrogen, the decrease of error of mean-square displacements of impurity atoms can be achieved by introducing of a large number of the impurities.

Abstract: In the work we propose a method for determining of the formation energy of bivacancy using molecular dynamics method. The key moment of the method for determining of the formation energy of bivacancy is the use of the value ζ, the minimum work that must be spent to remove one atom to infinity from the kink in the monatomic step on the surface of the crystal, calculated indirectly through the experimental data on the formation energy of the vacancy and the sublimation energy. The energy of migration of bivacancy in the work was determined from the temperature dependence of the diffusion coefficient when one bivacancy was introduced into the calculation block.

Abstract: During large strain deformation of polycrystals, grain or interphase boundaries are driven by the material flow, which is a convection movement. By contrast, upon static recrystallization or grain growth, their motion takes place with respect to matter, which is referred to as grain boundary or interphase migration. During hot working, where dynamic phase transformations commonly occur, convection and migration operate simultaneously. According to local geometrical (e.g., prescribed velocity field, grain boundary curvature) and physical (e.g., grain boundary mobility, dislocation densities) conditions, they can reinforce or oppose each other, but generally combine in more complex ways. The aim of this work is to analyze such effects on the basis of simple analytical approaches. The results suggest that second phase particles or grains dynamically generated (i.e., during straining) exhibit approximately equiaxed shapes.