Abstract: The main objective of this research was to study the differences of aluminum hydrolytic products between two PACl preparation methods. These two methods were the acidification process of freshly formed amorphous Al(OH)3 and the conventional alkalization process of aluminum chloride solution. According to Ferron test and 27Al NMR analysis of those two PACl preparation procedures, the reaction rate constant (k) values and Al13 percentage of acid addition process at high basicity value were both lower than those values of the alkaline addition process. The results showed that the molecular structure and size distribution of the aluminum species in both preparing methods were suspected to be significantly different at high basicity value.
Abstract: The exemplary mechanical performance and durability of ultra-high performance concrete (UHPC) has led to its rapid emergence as an advanced cementitious material. The uncharacteristically high mechanical strength and ductility of UHPC makes it a promising potential material for defense structures which may be subject to highly dynamic loads like impact or blast. However, the mechanical response of UHPC under dynamic loading has not been fully characterized. In particular, there is a need to characterize the energy absorption of UHPC under high-frequency shear loading. This paper presents preliminary results from a parametric study of the dynamic shear energy absorption of UHPC using the Charpy impact test. UHPC mixtures with compressive strengths in the range of 100-150 MPa exhibited dynamic shear energy absorption in the range of 0.9-1.5 kJ/m. Energy absorption is shown to be sensitive to the water/cement ratio, silica fume content, and aggregate gradation. Energy absorption was weakly correlated to compressive strength. Results are highly sensitive to specimen preparation methods, and there is a demonstrated need for a standardized test method for high frequency shear in cementitious composites.
Abstract: The effect of transition metal doping on Pt/Al2O3
catalyst used in propane dehydrogenation reaction at 500°C was
studied. The preparation methods investigated were sequential
impregnation (Pt followed by the 2nd metal or the 2nd metal followed
by Pt) and co-impregnation. The metal contents of these catalysts
were fixed as the weight ratio of Pt per the 2nd metal of around 0.075.
These catalysts were characterized by N2-physisorption, TPR, COchemisorption
and NH3-TPD. It was found that the impregnated 2nd
metal had an effect upon reducibility of Pt due to its interaction with
transition metal-containing structure. This was in agreement with the
CO-chemisorption result that the presence of Pt metal, which is a
result from Pt species reduction, was decreased. The total acidity of
bimetallic catalysts is decreased but the strong acidity is slightly
increased. It was found that the stability of bimetallic catalysts
prepared by co-impregnation and sequential impregnation where the
2nd metal was impregnated before Pt were better than that of
monometallic catalyst (undoped Pt one) due to the forming of Pt sites
located on the transition metal-oxide modified surface. Among all
preparation methods, the sequential impregnation method- having Pt
impregnated before the 2nd metal gave the worst stability because this
catalyst lacked the modified Pt sites and some fraction of Pt sites was
covered by the 2nd metal.
Abstract: The development of active and stable catalysts
without noble metals for low temperature oxidation of exhaust gases
remains a significant challenge. The purpose of this study is to
determine the influence of the preparation method on the catalytic
activity of the supported copper-manganese mixed oxides in terms of
VOCs oxidation. The catalysts were prepared by impregnation of γ-
Al2O3 with copper and manganese nitrates and acetates and the
possibilities for CO, CH3OH and dimethyl ether (DME) oxidation
were evaluated using continuous flow equipment with a four-channel
isothermal stainless steel reactor. Effect of the support, Cu/Mn mole
ratio, heat treatment of the precursor and active component loading
were investigated. Highly active alumina supported Cu-Mn catalysts
for CO and VOCs oxidation were synthesized. The effect of
preparation conditions on the activity behavior of the catalysts was
discussed.
The synergetic interaction between copper and manganese species
increases the activity for complete oxidation over mixed catalysts.
Type of support, calcination temperature and active component
loading along with catalyst composition are important factors,
determining catalytic activity. Cu/Mn molar ratio of 1:5, heat
treatment at 450oC and 20 % active component loading are the best
compromise for production of active catalyst for simultaneous
combustion of CO, CH3OH and DME.
Abstract: Use of plants grown in local area for edible has a long tradition in different culture. The indigenous knowledge such as usage of plants as vegetables by local people is risk to disappear when no records are done. In order to conserve and transfer this valuable heritage to the new generation, ethnobotanical study should be investigated and documented. The survey of vegetable plants traditionally used was carried out in the year 2012. Information was accumulated via questionnaires and oral interviewing from 100 people living in 36 villages of 9 districts in Amphoe Huai Mek, Kalasin, Thailand. Local plant names, utilized parts and preparation methods of the plants were recorded. Each mentioned plant species were collected and voucher specimens were prepared. A total of 55 vegetable plant species belonging to 34 families and 54 genera were identified. The plant habits were tree, shrub, herb, climber, and shrubby fern at 21.82%, 18.18%, 38.18%, 20.00% and 1.82% respectively. The most encountered vegetable plant families were Leguminosae (20%), Cucurbitaceae (7.27%), Apiaceae (5.45%), whereas families with 3.64% uses were Araceae, Bignoniaceae, Lamiaceae, Passifloraceae, Piperaceae and Solanaceae. The most common consumptions were fresh or brief boiled young shoot or young leaf as side dishes of ‘jaeo, laab, namprik, pon’ or curries. Most locally known vegetables included 45% of the studied plants which grow along road side, backyard garden, hedgerow, open forest and rice field.
Abstract: The aim of present work was to optimize the effect of Ethyl Cellulose (EC) and Polyvinyl Pyrrolidone (PVP) concentration in extended release solid dispersion of Glibenclamide using combination of hydrophilic and hydrophobic polymers such as Polyvinyl Pyrrolidone and Ethyl cellulose. The advantage of solid dispersion technique provides a unique approach to particle size reduction and increased rates of dissolution. The compatibility studies of the drug and polymers were studied by TLC and results suggested no interaction between drug and polymers. Solid dispersions of Glibenclamide were prepared by common solvent evaporation method using Polyvinyl Pyrrolidone and Ethyl cellulose. The results indicated that homogeneous or heterogeneous conditions during the preparation methods employed governed the internal structures of the polymer matrices while retaining the drug in an amorphous form. F2 formulation prepared by solid dispersion method, displayed extended drug release followed by Higuchi matrix model indicating diffusion release of GLB from polymer matrices.
Abstract: To study the effect of suitable methods for
propagation of True Potato Seed (TPS) progenies, transplant and
selection of the best progenies, a factorial experiment base on a
randomized complete block design was carried out in the research
field of Sahneh region, Kermanshah, Iran during 2009-2010. Five
selective progenies from CIP (International Potato Center) including
CIP.994013, CIP.994002, CIP.994014, CIP.888006, and
CIP.994001 and two transplant preparation methods (Paper pot
preparation for mechanical cultivation and preparation in transplant
trays for manual cultivation) were studied in three replications.
Results showed that different progenies had no significant effect on
plant height (cm) and tuber yield (t ha-1), whereas had a significant
effect on number of tubers per unit area (m2). There was significant
difference between transplant preparation methods for plant height
and tuber yield. The interaction effect of progenies and transplant
preparation method was not significant for these traits. CIP.888006
progeny and paper pot preparation method produced the highest
tuber yields. Also CIP.994002 and CIP.994014 progenies considered
as the best progenies under paper pot preparation method due to high
yields.
Abstract: Nanophotocatalysts such as titanium (TiO2), zinc (ZnO), and iron (Fe2O3) oxides can be used in organic pollutants oxidation, and in many other applications. But among the challenges for technological application (scale-up) of the nanotechnology scientific developments two aspects are still little explored: research on environmental risk of the nanomaterials preparation methods, and the study of nanomaterials properties and/or performance variability. The environmental analysis was performed for six different methods of ZnO nanoparticles synthesis, and showed that it is possible to identify the more environmentally compatible process even at laboratory scale research. The obtained ZnO nanoparticles were tested as photocatalysts, and increased the degradation rate of the Rhodamine B dye up to 30 times.