Modeling Infiltration Kinetics Of Liquids Into Porous Alumina Preforms

MODELING INFILTRATION KINETICS OF LIQUIDS INTO POROUS ALUMINA PREFORMS. Alpha-alumina preform was infiltrated with different infiltrant and pressure for studying the infiltration kinetic. Effects of pre-sintering temperature, type of infiltrant, pressure and multiple infiltrations on the rate of infiltration into porous alumina preforms were described. The pore radius of alumina preform is calculated based on the preform water system by using Washburn model. The pore radius from this model, r of 0.0147 μm is good agreement to the average pore radius found by using mercury porosity measurement, r of 0.0170 μm. The pore radius of 0.0147 μm is used to calculate the rate of infiltration, k. The k factors are 64.83 x 10-5 ms½ and 27.11 x 10-5 ms½ for water and TiCl3 respectively without involving pressure in the calculation. On the other hand, by using pressure, the k factors are 75.14 x 10-5 ms½ and 31.40 x 10-5 ms½ for water and TiCl3 respectively. Other formulas were also included as comparisons. The kinetic of water and titanium trichloride alumina preform system is parabolic in time or linier in square root of time

Viabilitas Dan Keriap Bacillus SP. Bk17 Dan Enterobacter SP. Bk15 Pada Sumber Karbon Dan Nitrogen Yang Berbeda

To propagate bacterial cell for biocontrol purpose, suitable nutrient have to be determined in which carbon and nitrogen source was often as limited factor of bacterial growth. Proper storage for biocontrol agent such as bacterial cell should also be considered in order to keep the cell viable when used. The aim of this study is to find out suitable carbon and nitrogen sources for viability and swarming of chitinolitic bacterial Bacillus sp. BK17 and Enterobacter sp. BK15. The highest population of bacterial growth (3.7x108 cfu/ml) was found in molases-sodium nitrate (MS) medium and the lowest population was found in crab shell-sodium nitrate (CS) growth (2.4x108 cfu/ml) after 25 days of incubation. The swarming activity of the isolates were varied to some extent with the highest was 51 mm in 2% agar molases-urea after 5 days of incubation. Molases-sodium nitrate (MS) medium is suitable carbon and nitrogen source for the viability of Bacillus sp. and Enterobacter sp. Meanwhile, agar molases-urea medium with 2% agar is suitable medium for swarming ability for both bacteria

Pengendalian Sel Biofilm Bakteri Patogen Oportunistik dengan Panas dan Klorin

Opportunistic pathogenic bacteria are bacteria that are naturally not present in an environment that, but it dues to contamination of the environment by human waste. From previous research it was found E. coli, Staphylococcus sp. and Salmonella were opportunistic pathogens of the shrimp aquaculture (Percut, Pantai Labu, Pantai Cermin). The aims of this study is to know the ability of these bacteria to form biofilms as well as its control using chlorine and heat. In order to test the ability of the bacteria to form biofilms, the stainless steel have been soaked in SWC media for 1, 3, 6 days. E. coli, Salmonella, and Staphylococcus sp. may form biofilms on incubation of the 1st day but the highest growth was on the 6th day of incubation by E. coli with a 6,35 x 104 CFU/SS, whereas of the lowest biofilm number was found in Salmonella with a 0,28 x 104 CFU/SS. The number of biofilm cells grow in line with a length of incubation. In this research, the most effective concentration of chlorine to kill biofilm cell was 225 ppm for 2 minutes and heat was 100 0C for 5 minutes. The higher the concentration of chlorine and the temperature given more effective to kill the bacteria

Seleksi Bakteri Penambat Nitrogen Dan Penghasil Hormon Iaa (Indole Acetic Acid) Dari Rizosfer Tanah Perkebunan Kedelai (Glycine Max L.)

Rizosphere bacteria can be used to fix nitrogen and produce IAA (Indol Acetic Acid) as biofertilizer to support plant growth. The ability of rhizosphere bacteria can be improved using biotechnology. The aim of this study is to select the most potential nitrogen fixing and IAA producing bacteria. Nitrogen fixing and IAA producing bacteria were isolated using JNFB and Luria Bertani + L-tryptofan medium respectively. The ability of nitrogen fixing bacteria were tested by ARA method, while the ability of IAA producing bacteria were investigated by spectrophotometer technique of 535 nm. The highest IAA concentration was produced by isolate I3 which was 33.3 ppm and the highest concentration of nitrogen was yielded by isolate N3 which was 29.93 ppm. Both N3 isolate and I3 isolate potentially as biofertilizer known as PGPR (Plant Growth Promoting Rhizobacteria)

The integrated DL_POLY/DL_FIELD/DL_ANALYSER software platform for molecular dynamics simulations for exploration of the synthonic interactions in saturated benzoic acid/hexane solutions

Three separately developed software Molecular Dynamics packages at Daresbury Laboratory, namely DL_FIELD (DL_F), DL_POLY and DL_ANALYSER, have been integrated to form an efficient computational infrastructure to investigate the detailed solution chemistry of saturated benzoic acid in hexane solutions. These software capabilities are demonstrated, in combination with the Synthonic Engineering tools and density functional theory (DFT) calculations, to assess the extent that the solute-solute intermolecular synthonic interactions in solution mirrors the synthons in the crystal structure. The results show that the majority of the COOH groups are forming OH … O H-bonds, which are a combination of classic OH … O homo-dimers and three membered H-bonding clusters. The formation of pi-pi stacking interactions is observed, but in far fewer numbers than observed for the OH … O interactions. The DFT simulations of the IR spectra of the multiple benzoic acid aggregates extracted from the MD trajectories provides further in-depth analysis of previously published IR data, by matching simulated peaks to the experimental peaks, hence identifying the exact bonding modes that are responsible for such peaks. This study demonstrates the value of a multi-scale and multi-technique approach to exploring the molecular transition pathway from solution to crystal structure

Influence of malaria on the serum levels of vitamin A, zinc and calcium of children in Douala-Cameroon

Malaria is an endemic parasitic disease that prevails particularly in warm tropical regions of the world. Micronutrient malnutrition such as vitamin A and iron deficiencies which is a public health problem inCameroon is usually highly prevalent in malaria endemic areas. Characterizing the relationship between micronutrient status (vitamin A, zinc and calcium) and malaria infection among children in Douala town (Cameroon), serum levels of zinc, calcium and vitamin A, were assayed in a total of 116 Cameroonian children (62 controls and 54 malaria patients infected by Plasmodium falciparum) less than six yearsold by colorimetric and high pressure liquid chromatography (HPLC) techniques respectively showed a significantly lower vitamin A and calcium concentrations (P < 0.01) among malaria patients (0.8 ± 0.4ìmol/l and 81.3 ± 23.7 mg/l) as compared to the controls (1.1 ± 0.6 ìmol/l and 96.3 ± 16.7 mg/ml). Vitamin A, calcium and zinc status were lower in 51.85%, 51.85% and 27.27% of malaria patients respectively. Significant correlations (

Vulnérabilité des troupeaux transhumants aux mutations climatiques : analyse des perceptions et adaptations locales dans le bassin de la Sota à Malanville

L’élevage bovin occupe une place importante parmi les activités des populations du Nord-Est du Bénin. Cette activité est très vulnérable aux mutations climatiques dans le bassin de la Sota à Malanville situé à l’extrême Nord-Est du Bénin. La présente recherche vise, d’une part, à appréhender, les perceptions des agro-éleveurs et des éleveurs sur les mutations climatiques et à analyser, d’autre part, leurs stratégies pour y faire face. Les données sur les perceptions et les stratégies d’adaptation ont été collectées au moyen d’enquêtes faites par entretiens, focus groupes et questionnaires dans cinq (5) villages choisis de manière aléatoire. Le calcul du taux moyen de réponse et l’analyse en composantes principales ont été utilisés pour analyser ces données. Les résultats montrent une grande similitude des manifestations des mutations climatiques perçues par les agro-éleveurs et éleveurs. Les manifestations les plus citées sont: la hausse des températures (citée par 99,16% des agro-éleveurs et 100% des éleveurs), les poches de sécheresse prolongée (citée par 67,5% des agro-éleveurs et 91,66% des éleveurs), les vents forts et violents (citée par 70% des agro-éleveurs et 87,08% des éleveurs). Pour ce qui concerne les effets des mutations climatiques, les agro-éleveurs et les éleveurs en perçoivent respectivement 9 et 11.Pour les premiers, les effets les plus marquants sont l’assèchement des points d’eau (80%), l’amenuisement du disponible fourrager (71,42%), la contamination et le comblement des points d’eau (65%). Pour les seconds, ce sont: l’amenuisement du disponible fourrager (96,66%), la contamination et le comblement des points d’eau (92,50%), l’assèchement précoce des points d'eau (91,50%), l’affaiblissement des animaux (57,50%), l’amaigrissement des animaux (56,66%). En réponse à cette instabilité du climat et ses effets, les agro-éleveurs et les éleveurs ont développé des stratégies dont les principales (communes aux deux groupes socio-professionnels) sont : le respect des campagnes de vaccination (citée par 85% des agro-éleveurs et 97,50% des éleveurs), l’abreuvement au fleuve ou à la rivière (citée par 37,50% des agro-éleveurs et 55% des éleveurs), la mobilité spatiale (citée par 59,50% des agro-éleveurs et 55% des éleveurs). Les résultats du test de Mann Whitney indiquent une différence significative de perception au seuil de 5% pour les effets, manifestations et stratégies communs aux deux groupes socioprofessionnelsMots-clés: mutations climatiques, perceptions et stratégies d’adaptation, agro-éleveurs et éleveurs, vulnérabilité, bassin de la Sota, Malanville. Vulnerability of transhumant herds to the climatic mutations: analysis of the perceptions and local adaptations in the watershed of Sota at MalanvilleThe bovine breeding occupies a significant place among the activities of the populations of the North-East of the Benin. This activity is very vulnerable to the climatic mutations in the watershed of Sota at Malanville located at the far North-East of Benin. This research aims, on the one hand, to understand the perceptions of the agro-pastoralists and the stockbreeders on the climatic mutations and, on the other hand, to analyze the strategies implemented by them to face there. The data on perceptions and the strategies of adaptation of the agro-pastoralists and the stockbreeders were collected using interviews, focus groups and questionnaires in five (5) villages randomly selected. The calculation of the response rate and the analysis in principal components were used to analyze the data. The results show a great similarity of the manifestations of the climatic mutations perceived by the agro-pastoralists and the stockbreeders. The most quoted manifestations are: the temperatures increase (quoted by 99.16% of the agro-pastoralists and 100% of the stockbreeders), prolonged dry spells (quoted by 67.5% of the agro-pastoralists and 91.66% of the stockbreeders), strong and violent winds (quoted by 70% of the agro-pastoralists and 87.08% of the stockbreeders). Concerning the effects of climatic mutations, the agro-pastoralists and the stockbreeders perceive respectively 9 and 11.For the firsts, the most significant effects are the drying up of the water points (80%), the dwindling of available forage (71.42%), the contamination and the filling of the water points (65%). For the seconds the main effects are: the dwindling of available forage (96.66%), the contamination and the filling of the water points (92.50%), premature drying up of the water points (91.50%), the weakening of the animals (57.50%), the slimming of the animals (56,66%). In response to this instability of the climate and its effects, the agro-pastoralists and the stockbreeders developed strategies. The main common strategies are: the respect of the vaccination campaigns (quoted by 85% of the agro-pastoralists and 97.50% of the stockbreeders), watering at the river (quoted by 37.50% of the agro-pastoralists and 55% of the stockbreeders) and spatial mobility (quoted by 59.50% of the agro-pastoralists and 55% of the stockbreeders). The results of the Mann Whitney test indicated a significant difference in perception threshold of 5% for effects, manifestations and strategies common to both socio professional groups.Keywords: climatic mutations, perceptions and strategies of adaptation, agro-pastoralists, stockbreeders, vulnerability, watershed of Sota, Malanville