Journal of Applied Sciences
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Open Access journal
ISSN (Print) 1812-5654 - ISSN (Online) 1812-5662
Published by ANSInet [31 journals]
- Sedimentology and Reservoir Geometry of the Miocene Carbonate Deposits in
Central Luconia, Offshore, Sarawak, Malaysia
Abstract: Background: Carbonate buildups in Central Luconia are proven prolific hydrocarbon reservoirs, represented by thick limestone deposits with a minor proportion of dolomitic limestone. The limestone diversity attracted the considerable attention of oil and gas companies and geologists from all over the world. However, owing to many changes in lithology, facies characteristics and reservoir prediction of this formation, industry players still face challenges to identify and corroborate the lithology, facies and reservoir occurrence. Objective: To have better understanding on the reservoir quality and to increase hydrocarbon production, the current study aims to identify the lithofacies, depositional environment and diagenetic process which influence the reservoir rock. Methodology: Core description was conducted, core plugs were collected and thin sections of these core plugs were prepared. Results: The Central Luconia carbonates are divided into 8 facies. Based on the sedimentary structure, texture, components and fossils contents, 5 facies are identified in well A and B, namely: (1) Coated grain packstone, (2) Coral massive (m) lime grainstone, (3) Oncolite lime grain packstone, (4) Skeletal lime packstone and (5) Coral platy (p) lime mud packstone. Facies 4 is the dominant facies types in well A and B. Biota includes red algae, coral, foraminifera, echinoderm, sponge, green algae, bryozoans and bivalve. Visible porosity is from poor to very good. It varies in different facies with common open moulds and small vugs. However, low (Facies 1 and 5) to moderate (Facies 2, 3 and 5) permeability valves suggests that matrix porosity provides only limited interconnection between the large moldic pores. Many pores appear to form an early leaching of foraminifera and corals in facies 2 and 4. Conclusion: Deposition environment is interpreted to be lagoonal condition for these facies based on the features of the biotic assemblage. Lithofacies indicate a good quality reservoir, but diagenesis plays an important role in creating and destroying porosity. The main diagenetic processes affecting the reservoir quality are compaction including stylolite and cementation of calcite and dolomite. Whereas the dissolution is the main diagenetic processes in improving porosity and mechanical compaction enhancing permeability by forming small fractures.
PubDate: 15 March, 2017
- Antimicrobial Activity of Two Polysaccharide Edible Films
with Essential Oils against Three Pathogenic Bacteria
Abstract: Background: Nowadays, packaging research is receiving considerable attention because of the development of eco-friendly materialsmade from natural polymers such as chitosan (CH) and hydroxypropyl methylcellulose (HPMC). Essential oils are effective antimicrobialson important some pathogenic bacteria and can be added packaging materials due to absorb various surfaces. Objective: The mainpurposed of this study was to prepared antimicrobial films by incorporating different concentrations of marjoram, clove and cinnamonessential oils, into chitosan and hydroxypropyl methylcellulose films against foodborne pathogens. Methodology: Chitosan (1% w/w)was dispersed in an aqueous solution of glacial acetic acid (0.5% w/w) at 25°C. Following overnight agitation, essential oils were addedto the chitosan solution. Hydroxypropyl methylcellulose 1% weight was dispersed in de-ionized water at 80°C. After the dissolution ofthe polysaccharide, essential oils were added. Essential oils clove (Syzgium aromaticum), marjoram (Origanum majorana ) and cinnamon(Cinnamomum zeylanicum ) were extracted by hydro-distillation. The antibacterial effects of essential oils were studied against threeimportant food pathogens, Escherichia coli, Staphylococcus aureus and Listeria monocytogenes by application of agar diffusion method.Also, antimicrobial effectiveness of films were studied by tryptone soy agar with 3% NaCl was used as a model solid food system(TSA-NaCl). Results: The intensity of antimicrobial efficacy was in the following order: Marjoram>clove>cinnamon. The antibacterialeffectiveness of the prepared films against E. coli , S. aureus and L. monocytogenes was studied at 10°C during 12 days. The HPMC-EOand CH-EO composite films present a significant antimicrobial activity against the three pathogens considered. In all film matrices,marjoram exhibited the highest antimicrobial activity. A complete inhibition of microbial growth was observed for CH or HPMC-marjoramfilms for E. coli , HPMC-marjoram for L. monocytogenes and HPMC-clove for S. aureus . Conclusion: The HPMC-EO and CH-EO compositefilms, containing clove, cinnamon or marjoram, showed a significant antimicrobial activity (bacteriostatic effect) against the threepathogens studied (E. coli , L. monocytogenes and S. aureus ). In all film matrices, marjoram exhibited the highest antimicrobial activity.
PubDate: 15 March, 2017
- Anti-mycotic and Anti-mycotoxigenic Properties of Egyptian Dill
Abstract: Background: Dill (Anethum graveolens) is considered as one of the medicinal herbal plants which were known from ancient Egyptian centaury. Dill had many benefits for healthcare and it could be used in some parts of the world as food additives. Gas chromatography of dill declared many major and minor components also phyto-constituents that may play an important role in the inhibition of toxigenic fungal growth and/or mycotoxin reductions. One of the major components that had importance was carvone also limonene and apiol otherwise terpenoids and tannins considered as minor ones. Materials and Methods: Effect of three types of dill (Anethum graveolens) products were studied to compare its ability to avoid fungal growth of six strains of toxigenic fungi, dill products were leaves and stems extract, roots extracts and seeds essential oil, meanwhile, the strains were Aspergillus flavus ITEM 8080, Aspergillus parasiticus ITEM 692, Aspergillus ochraceus ITEM 2456, Penicillum verrucosum ISPA 9618, Fusarium graminearum ISPA2020 and Aspergillus niger ITEM 2318. Results: Dills seeds essential oil appeared to be the most effective one could inhibit fungal growth of the toxigenic fungi at a concentration of 5 mg mL1 of seeds essential oil the fungal growth of all toxigenic fungi under the study was avoided. Use of seeds essential oil as anti mycotoxigenic material against aflatoxin B1 and aflatoxin G1 was determined. Conclusion: By increasing the concentration of seeds essential oil in media, reduction effect increased either for aflatoxin B1 or for aflatoxin G1 toxins at a concentration of 5 mg mL1 essential oil extract inhibition ratio reached 87.7% for aflatoxin B1 and for aflatoxin G1 it was 92.2% reducing of toxin.
PubDate: 15 March, 2017
- Population Proportion Estimator of Respondent Driven Sampling for
Non-dichotomous Variables, Data Smoothing Approach
Abstract: Background: Sampling and estimating of hidden population sizes, such as injection drug users are important issues for health policy makers, because of exposing these populations to high risks diseases, such as HIV/AIDS. Materials and Methods: Respondent driven sampling is a successful method in terms of resulting in representative sample of hidden populations and finding unbiased estimates comparing to the other existing conventional methods. Results: The main purpose of this study is to define population proportion estimation of this sampling method for dichotomous and non-dichotomous variables. For non-dichotomous variables, reciprocal approach results in over-determination equations which can be solved by either least squares or data smoothing approaches, though the late one is much more effective. A hypothetical data has been employed to find the estimation of dichotomous and non-dichotomous variables for respondent driven sampling method. Conclusion: The novelty of data smoothing procedure to find respondent driven sampling estimates has been proved by this hypothetical data. Respondent driven sampling method could result in unbiased estimates of population proportions and it has been recommended to be applied for studying hidden population proportions.
PubDate: 15 March, 2017
- Evaluation of Parallel Self-organizing Map Using Heterogeneous System
Abstract: Background: Self-organizing map (SOM) is a very popular algorithm that has been used as clustering algorithm and data exploration. The SOM consists of complex calculations where the calculation of complexity depending on the circumstances. Many researchers successfully improve SOM processing speed using discrete Graphic Processing Units (GPU) since the introduction of Compute Unified Device Architecture (CUDA) in 2007 and Open Computing Language (OpenCL) in 2009. In spite of excellent performance using GPU, there are performance issues in processing a large mapping size especially dealing with find the Best Matching Unit (BMU) and updating weightage. Additionally, the larger mapping size also could burden the processing through the usage of high memory capacity which leads to high rate memory transfer. Recently, heterogeneous systems, that soldered CPU and GPU together on a single chip are rapidly attractive the design paradigm for todays platform because of their remarkable parallel processing abilities. Therefore, this study evaluates parallel SOM performance on discrete GPU and heterogeneous system in order to improve the algorithm processing. Materials and Methods: Accordingly, this study demonstrates parallel SOM that comprises of three kernels. The parallel SOM then executes on two different platforms: (1) Discrete GPU platform and (2) Heterogeneous system platform. This study evaluates the outcomes of the computation experiments based on computation time and SOM quality measurements. Results: As a result, parallel SOM that executed on heterogeneous system platform is able to reduce the total processing time compared to discrete GPU platform when processing large mapping sizes and large data sets. Conclusion: More important, this study highlights how the proposed parallel SOM can improve the execution performance and maintain the SOM results when running on heterogeneous system.
PubDate: 15 March, 2017