25 research outputs found
Startegi Peningkatan Prestasi Belajar Siswa SD X di Salatiga Ditinjau dari Motivasi Belajar dan Kedisiplinan
Pendidikan formal dimulai dari tahap sekolah dasar dimana seorang anak mendapatkan semua informasi yang dialami dalam kehidupan sehari-hari. Luas wilayah Indonesia yang sangat luas menjadi salah satu faktor kurangnya kemerataan kualitas, mutu dan sumberdaya yang ada. Kualitas pendiidkan dapat dilihat dari hasil belajar siswa. Salah satu faktor yang mempengaruhi hasil belajar adalah motivasi belajar dan kedisiplinan. Kedua hal tersebut memiliki keterkaitan satu sama lain terhasap hasil belajar. Oleh karena itu, dilakukan sebuah penelitian tentang apa strategi yang dilakukan untuk meningkatkan prestasi belajar siswa SD X di Salatiga ditinjau dari motivasi belajar dan kedisiplinan. Untuk mendapatkan jawaban dari pertanyaan di atas maka dilakukan sebuah penelitian dengan teknik pengumpulan data berupa wawancara dan pengambilan nilai sebagai hasil belajar siswa. Setelah data dianalisis dapat diketahui bahwa data tersebut normal sehingga dilakukan tindak lanjut dengan medan ggunakan uji normalitas data menggunakan metode stepwise. Uji tersebut menghasilkan faktor yang paling mempengaruhi hasil belajar siswa adalah disiplin. Berdasarkan hasil analisis yang dilakukan, maka perlu dilakukan treatment khusus pada disiplin siswa sehingga dapat berpengaruh juga pada hasil belajar
Microbial Enhanced Heavy Oil Recovery by the Aid of Inhabitant Spore-Forming Bacteria: An Insight Review
Crude oil is the major source of energy worldwide being exploited as a source of economy, including Oman. As the price of crude oil increases and crude oil reserves collapse, exploitation of oil resources in mature reservoirs is essential for meeting future energy demands. As conventional recovery methods currently used have become less efficient for the needs, there is a continuous demand of developing a new technology which helps in the upgradation of heavy crude oil. Microbial enhanced oil recovery (MEOR) is an important tertiary oil recovery method which is cost-effective and eco-friendly technology to drive the residual oil trapped in the reservoirs. The potential of microorganisms to degrade heavy crude oil to reduce viscosity is considered to be very effective in MEOR. Earlier studies of MEOR (1950s) were based on three broad areas: injection, dispersion, and propagation of microorganisms in petroleum reservoirs; selective degradation of oil components to improve flow characteristics; and production of metabolites by microorganisms and their effects. Since thermophilic spore-forming bacteria can thrive in very extreme conditions in oil reservoirs, they are the most suitable organisms for the purpose. This paper contains the review of work done with thermophilic spore-forming bacteria by different researchers
Stability of Superoxide Ion in Phosphonium-Based Ionic Liquids
In
this work the chemical generation of superoxide ion and determination
of its stability in five phosphonium-based ionic liquids has been
carried out. The stability of the generated superoxide ion depended
on the anion. For the trihexylÂ(tetradecyl)Âphosphonium cation, the
bisÂ(2,4,4-trimethylpentyl)Âphosphinate anion (IL 104) has shown a relatively
good stability with a rate constant of 3.34 Ă— 10<sup>–5</sup> s<sup>–1</sup> for the reaction of the superoxide ion. TriisobutylÂ(methyl)Âphosphonium
tosylate has also shown moderate stability (6.8 Ă— 10<sup>–5</sup> s<sup>–1</sup>). The order of stability, bisÂ(2,4,4-trimethylpentyl)Âphosphinate
> dicyanamide (6.97 × 10<sup>–5</sup> s<sup>–1</sup>) > Br<sup>–</sup> (7.72 × 10<sup>–5</sup> s<sup>–1</sup>) > Cl<sup>–</sup> (12.7 × 10<sup>–5</sup> s<sup>–1</sup>), correlates well with the order of their
respective ionic volumes. On application of the generated superoxide
ion for the oxidation of two organic sulfur compounds, 15% conversion
of thiophene was attained in 2 h while dibenzothiophene (DBT) was
found to be unreactive to the ion in IL 104. This was attributed to
higher electron density on the sulfur atom in DBT relative to thiophene
and high nucleophilicity of the superoxide ion. Furthermore, the type
of IL appears to slightly affect the conversion. The conversion of
thiophene obtained was in the following order: IL 104 (15%) > [HMPyrr]Â[TFSI]
(8%) > [BMPyrr]Â[TFSI] (7%) with the apparent differences in the
magnitude
of the alkyl chain length
Solubility of Thiophene and Dibenzothiophene in Anhydrous FeCl<sub>3</sub>- and ZnCl<sub>2</sub>‑Based Deep Eutectic Solvents
The
solubilities of some common refractory-sulfur-containing compounds,
namely thiophene and dibenzothiophene, were studied and measured in
anhydrous FeCl<sub>3</sub>- and ZnCl<sub>2</sub>-based deep eutectic
solvents (DES) at different temperatures under atmospheric pressure.
The aim of this study is to explore the behavior of DESs toward solvation
of sulfur-containing compounds so as to set a pace for the successful
application of DESs into deep desulfurization of liquid fuels. The
studied DESs were screened and prepared by the combination of anhydrous
FeCl<sub>3</sub> and ZnCl<sub>2</sub> with different salts and hydrogen
bond donors. High pressure liquid chromatography (HPLC) was employed
for the quantitative measurements of solubilities of both thiophene
and dibenzothiophene. It was found that FeCl<sub>3</sub> based DESs
exhibited higher solubilities (from 17 wt % to above 90 wt %) for
dibenzothiophene as compared to the ZnCl<sub>2</sub> based DESs (0.084–1.389
wt %). Moreover, FeCl<sub>3</sub> based DESs exhibited complete miscibility
with thiophene while ZnCl<sub>2</sub> based DESs showed solubility
values in the range of 1–10 wt % for thiophene. The experimental
results obtained were further successfully modeled using the nonrandom
two liquid (NRTL) model
Analysis of Bacterial Diversity in Different Heavy Oil Wells of a Reservoir in South Oman with Alkaline pH
The identification of potential hydrocarbon utilizing bacteria is an essential requirement in microbial enhanced oil recovery (MEOR). Molecular approaches like proteomic and genomic characterization of the isolates are replacing the traditional method of identification with systemic classification. Genotypic profiling of the isolates includes fingerprint or pattern-based technique and sequence-based technique. Understanding community structure and dynamics is essential for studying diversity profiles and is challenging in the case of microbial analysis. The present study aims to understand the bacterial community composition from different heavy oil contaminated soil samples collected from geographically related oil well areas in Oman and to identify spore-forming hydrocarbon utilizing cultivable bacteria. V4 region of 16S rDNA gene was the target for Ion PGM™. A total of 825081 raw sequences were obtained from Ion torrent from all the 10 soil samples. The species richness and evenness were found to be moderate in all the samples with four main phyla, Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria, the most abundant being Firmicutes. Bacillus sp. ubiquitously dominated in all samples followed by Paenibacillus, which was followed by Brevibacillus, Planococcus, and Flavobacterium. Principal Coordinate Analysis (PCoA) and UPGMA dendrogram clustered the 10 soil samples into four main groups. Weighted UniFrac significance test determined that there was significant difference in the communities present in soil samples examined. It can be concluded that the microbial community was different in all the 10 soil samples with Bacillus and Paenibacillus sp. as predominating genus. The 16S rDNA sequencing of cultivable spore-forming bacteria identified the hydrocarbon utilizing bacteria as Bacillus and Paenibacillus sp. and the nucleotide sequences were submitted to NCBI GenBank under accession numbers KP119097–KP119115. Bacillus and Paenibacillus sp., which were relatively abundant in the oil fields, can be recommended to be chosen as candidates for hydrocarbon utilization study
Production, Characterization and Application of Bacillus licheniformis W16 Biosurfactant in Enhancing Oil Recovery
The biosurfactant production by Bacillus licheniformis W16 and evaluation of biosurfactant based enhanced oil recovery using core-flood under reservoir conditions were investigated. Previously reported nine different production media were screened for biosurfactant production, and two were further optimized with different carbon sources (glucose, sucrose, starch, cane molasses or date molasses), as well as the strain was screened for biosurfactant production during the growth in different media. The biosurfactant reduced the surface tension and interfacial tension to 24.33+0.57mN m-1 and 2.47+0.32mN m-1 respectively within 72h, at 40 C, and also altered the wettability of a hydrophobic surface by changing the contact angle from 55.67°+1.6° to 19.54°+0.96°. The critical micelle dilution values of 4X were observed. The biosurfactants were characterized by different analytical techniques and identified as lipopeptide, similar to lichenysin-A. The biosurfactant was stable over wide range of extreme environmental conditions. The core flood experiments showed that the biosurfactant was able to enhance the oil recovery by 24-26% over residual oil saturation (Sor). The results highlight the potential application of lipopeptide biosurfactant in wettability alteration and microbial enhanced oil recovery processes
The characteristics and patterns of utilization of healthcare services among Omanis with substance use disorders attending therapy for cessation.
BACKGROUND:It is indicated that Oman is witnessing an increase in issues pertinent to alcohol and psychoactive substance use. AIM:The aim of this study was to identify the characteristics of Omanis with substance use disorder attending a specialized hospital in Oman and the pattern of their utilization of healthcare services. A related aim was to ascertain the age group most vulnerable to alcohol and substance use in Oman. METHOD:A cross-sectional study was conducted in a tertiary care center specialized for treatment of those engaging in substance use in Oman. The participants in the study were selected from a convenience sample among patients seeking consultation at the center for alcohol and substance use. A six-part questionnaire was designed to obtain information regarding socio-demographic background, clinical history, healthcare utilization and perceived hurdles to access. Chi-square analyses were used to evaluate the significance of differences among categorical data. Logistic regression modelling was used to obtain measures of association after adjusting for confounding factors. RESULTS:Among the patients (n = 293) seeking cessation therapy, 99% were male and less than 30 years of age. Peer influences on the initiation of substance use were significant. Most patients had a history of polysubstance use, including intravenous substance use. Cannabis and alcohol were the first substances consumed by most patients and Hepatitis C and psychiatric disorders were found to be the most common co-morbidities. The participants that reported use of cannabis and benzodiazepines were more likely to perceive "improvement" upon receiving treatment. CONCLUSION:This study indicated that males below 30 years of age with a history of polysubstance use were likely to attend a hospital specialized in treating substance use disorder in Oman. This study identified information regarding socio-demographic background, risk factors and perceived hurdles to healthcare that could serve as groundwork for further studies conducted on newly emerging issues of substance use in Oman
Sophorolipids production by Candida bombicola ATCC 22214 and its potential application in microbial enhanced oil recovery
Biosurfactant production using Candida bombicola ATCC 22214, its characterization and potential applications in enhancing oil recovery was studied at laboratory scale. The seed media and the production media were standardized for optimal growth and biosurfactant production. The production media were tested with different carbon sources: glucose (2%w/v) and, corn oil (10%v/v) added separately or concurrently. The samples were collected at 24h interval up to 120h and checked for growth (OD660), and biosurfactant production (Surface tension and Interfacial tension). The medium with both glucose and corn oil gave better biosurfactant production and reduced both surface tension and interfacial tension to 28.56 + 0.42mN/m and 2.13 + 0.09mN/m, respectively within 72h. The produced biosurfactant was quite stable at 13-15% salinity, pH range of 2-12, and at temperature up to 100°C. It also produced stable emulsions (%E24) with different hydrocarbons (pentane, hexane, heptane, tridecane, tetradecane, hexadecane, 1-methylnaphthalene, 2,2,4,4,6,8-heptamethylnonane, light and heavy crude oil). The produced biosurfactant was extracted using ethyl acetate and characterized as a mixture of sophorolipids. The potential of sophorolipids in enhancing oil recovery was tested using core-flooding experiments, under reservoir conditions, where additional 27.27% of residual oil (Sor) was recovered. This confirmed the potential of sophorolipids for applications in microbial enhanced oil recovery