25 research outputs found
Self burial of offshore pipelines in fine grained cohesive sediment
No full textVita.Pipelines laid in soft cohesive sediments may attain burial because of their own weight. Shear strength of the sediment, pipe diameter, specific gravity of the pipe and the submerged unit weight of the sediment are the main parameters influencing the process of self burial of pipelines. Based on experimental studies, a theoretical procedure has been developed to predict initial sinkage of pipes. The contribution of consolidation settlement on total sinkage attained by a pipe has been studied through conventional procedure. The stress distribution in a soil mass underneath a pipe was ascertained by finite element analysis. Buoyancy tests were performed to determine the net weight of a pipe causing consolidation. Possible sinkage due to secondary consolidation of the sediment has been disregarded in this study. Experimental evidence of pipe sinkage in a test tank suggests the validity of the theoretical procedure developed- Parameter studies were conducted to show the influence of various parameters on the sinking process. Non-dimensional data analysis was performed to develop a family of curves which can be used to determine the minimum specific gravity of a pipe needed for self burial if the undrained shear strength of sediment and the diameter of the pipe are known. A discussion of the experimental results along with comparative studies of the procedures suggested by different investigators to determine initial pipe sinkage have been presented to bolster the applicability of the developed procedure. Recommendations have also been made for further relevant work
Nafas Sebagai Bagian dari Ekologi: Interpretasi QS. Al-Mursalat25-26 dalam Konteks Siklus Karbon
No full textArtikel ini membahas keterkaitan antara nafas manusia, ekologi, dan tafsir Al-Qur’an, khususnya pada QS. Al-Mursalat:25–26, dalam konteks siklus karbon. Melalui pendekatan interdisipliner antara agama dan sains, kajian ini mengungkap bahwa aktivitas bernapas bukan sekadar proses biologis, tetapi juga memiliki makna ekologis dan spiritual yang mendalam. Proses respirasi manusia berperan dalam pertukaran karbon dioksida (CO₂) dan oksigen (O₂), yang membentuk keseimbangan antara manusia, tumbuhan, dan bumi. Ayat Al-Mursalat:25–26 dipahami sebagai simbol keterpaduan kehidupan dan kematian dalam satu sistem ekologis ciptaan Allah. Dengan menempatkan nafas sebagai variabel epistemologis, penelitian ini memperluas wacana tafsir ekologi Al-Qur’an, memperlihatkan bahwa Islam memberikan dasar teologis bagi etika ekologis dan keberlanjutan lingkungan
Gas chromatography–mass spectrometry analysis of various organic extracts of Merremia borneensis from Sabah
No full textAbstractObjectiveTo analyse the chemical composition of different extracts of Merremia borneensis (M. borneensis) by gas chromatography-mass spectrometry (GC-MS).MethodsThe dried leaves powder was extracted with methanol at room temperature by using Soxhlet extractor. Methanol crude extracts of M. borneensis were extrastel with hexane, chloroform, ethyl acetate and butanol.ResultsQualitative analyses of various organic crude extracts showed that majority of these are flavonoids, terpeniods, alkaloids and glycosides. Most of the identified compounds by GC-MS are biologically important. Further the M. borneensis leaf possesses certain characteristics that can be ascribed to cultivation on a domestic plantation.ConclusionsThe suitable extracts for respective compounds can be chosen on the basis of above GC-MS analysis. All the major compounds from different extracts are biologically active molecules. Thus the identification of a good number of compounds from various extracts M. borneensis might have some ecological significance
In vitro total phenolics, flavonoids contents and antioxidant activity of essential oil, various organic extracts from the leaves of tropical medicinal plant Tetrastigma from Sabah
No full textAbstractObjectiveTo detect the in vitro total phenolics, flavonoids contents and antioxidant activity of essential oil, various organic extracts from the leaves of tropical medicinal plant Tetrastigma from Sabah.MethodsThe dry powder leaves of Tetrastigma were extracted with different organic solvent such as hexane, ethyl acetate, chloroform, butanol and aqueous methanol. The total phenolic and total flavonoids contents of the essential oil and various organic extracts such as hexane, ethyl acetate, chloroform, butanol and aqueous ethanol were determined by Folin - Ciocalteu method and the assayed antioxidant activity was determined in vitro models such as antioxidant capacity by radical scavenging activity using α, α-diphenyl- β-picrylhydrazyl (DPPH) method.ResultsThe total phenolic contents of the essential oil and different extracts as gallic acid equivalents were found to be highest in methanol extract (386.22 mg/g) followed by ethyl acetate (190.89 mg/g), chloroform (175.89 mg/g), hexane (173.44 mg/g), and butanol extract (131.72 mg/g) and the phenolic contents not detected in essential oil. The antioxidant capacity of the essential oil and different extracts as ascorbic acid standard was in the order of methanol extract > ethyl acetate extract >chloroform> butanol > hexane extract also the antioxidant activity was not detected in essential oil.ConclusionsThe findings show that the extent of antioxidant activity of the essential oil and all extracts are in accordance with the amount of phenolics present in that extract. Leaves of Tetrastigma being rich in phenolics may provide a good source of antioxidant
A study on the total phenols content and antioxidant activity of essential oil and different solvent extracts of endemic plant Merremia borneensis
No full textAbstractThis study is planned to determine the antioxidant activity and total phenols content of the essential oil and different solvent extracts of the endemic plant Merremia borneensis. The antioxidant activities of the extracts were examined by three different methods, DPPH, β-carotene and reducing power assays. In all methods, aqueous ethanol extract exhibited a higher activity potential than that of other extracts (hexane, chloroform, ethyl acetate and butanol) and the essential oil. As assumed, the amount of total phenolics was very high in this extract. Chloroform extract has been found to be rich in flavonoids. A positive result was observed between the antioxidant activity potential and total flavonoid levels of the extracts
Total flavonoids content and biochemical screening of the leaves of tropical endemic medicinal plant Merremia borneensis
No full textAbstractThe developing and under developed countries mostly rely on traditional medicines. This herbal or traditional medicine involves the use of different types of organic extracts or the bioactive chemical constituents. This type of biochemical investigation provides health care at an affordable cost. This survey such as ethnomedicine keenly represents one of the best avenues in searching new economic plants for medicines. Keeping this view in mind, the present study is carried out in Merremia borneensis leaves of University Malaysia Sabah, Sabah, Malaysia. The plant has several beneficial properties, such as antioxidant activity. The dry powder of the leaves of M. borneensis was extracted with hexane, ethyl acetate, chloroform, butanol and aqueous ethanol. The flavonoids content of the extracts was determined by Willet method. The flavonoids content of the extracts as quercetin equivalents was found to be highest in aqueous ethanol (53.28%) followed by chloroform (38.83%), ethyl acetate (24.51%), butanol (12.54%) and hexane extract (3.44%). The results suggest the presence of phytochemical properties in the leaves, which are used in curing the ailments
Exploring Gender Wage Gap in Urban Labor Market of Bangladesh
No full textUsing the Labor Force Survey 2010 dataset this paper examines gender wage gap in a large sample of urban workers in Bangladesh and explore whether gender wage gap varies across the wage distribution. Mincerian OLS regression and its Blinder-Oaxaca decomposition results reveal that the estimated wage gap between men and women workers is 21.2%. Adjusting women’s endowments levels to those of men increases women’s wage by 12.1% and a gap of 8.0% remains unexplained. The decomposition results based on the unconditional quantile regressions demonstrate that the estimated total gender wage gap is higher at lower end of the wage distribution compared to the higher end.</jats:p
Chemical composition and antibacterial properties of the essential oils and crude extracts of Merremia borneensis
No full textAbstractThe hydro distilled essential leaves and stems oils of Merremia borneensis were analysed by GC–MS. Sixty-nine compounds representing 96.81% and 89.89% of the leaves and stems oils, respectively, were identified, of which chloromethyl propanoate (3.29% and 3.54%), methylcyclopropanemethanol (1.29% and 1.03%), oxirane (1.41% and 1.05%), 1-penten-3-ol (1.33% and 1.12%), 1-(2-propenyloxy)-heptane (3.44% and 2.98%), camphene (4.11% and 3.65%), l-octen-3-ol (1.56% and 1.08%), α-pinene (2.98% and 2.12%), β-pinene (2.19% and 1.93%), 2-methyl-2-nitropropane (11.91% and 10.51%), bis(1,1-dimethylethyl)-diazene (1.25% and 1.71%), p-cymene (2.23% and 2.11%), limonene (1.28% and 1.11%), neopentane (12.02% and 11.95%), cyclopropyl methyl carbinol (2.19% and 1.99%), cis-2-octenal (1.29% and 1.13%), 4-undecanone (4.11% and 3.99%), menthone (1.99% and 1.73%), isomenthone (1.01% and 0.93%), methylchavicol (1.57% and 2.22%), dodecane (1.01% and 0.72%), eugenol (3.12% and 3.09%), β-elemene (1.99% and 1.89%), methyleugenol (1.42% and 1.13%), β-carryophyllene (1.12% and 1.05%), α-humulene (6.54% and 6.32%), tridecane (1.16% and 1.08%) were the major compounds. Thus, different types of monoterpenes and sesquiterpenes were the predominant portions of the oils. Essential oils and methanol extract of M. borneensis and the derived fractions of hexane, chloroform, and ethyl acetate were tested for antibacterial activity, which was determined by disc diffusion and minimum inhibitory concentration (MIC) determination methods. The oils, methanol extract and derived fractions of methanol extract did not display any potential of antibacterial activity against the tested 10 phytopathogenic bacterial such as Enterobacter cloacae, Staphylococcus aureus, Escherichia coli, Bacillus cereus, Salmonella typhimurium, Salmonella biafra, Klebsiella pneumoniae, Vibrio cholerae and Vibrio parahaemolyticus, in the range of 0% and minimum inhibitory concentration ranging from 25 to 100μg/ml
Evaluation of Well-Being Status of Near-Threatened Gangetic Leaf Fish Nandus nandus (Hamilton, 1822) in the Kawadighi Haor: Implications to Haor Fishery Management in the Northeastern Bangladesh
No full textThis study evaluated the status of the well-being of wild Nandus nandus in the Kawadighi Haor through morphometric and gastrointestinal indices and local people’s perceptions. Basic macroscopic morphology of the gastrointestinal tract (GIT), the viscera somatic index (VSI), the hepatosomatic index (HSI), the condition factor (K), length–weight relationships, and gut histology were analyzed from the regular commercial catch. The GIT morphology includes a tube-like esophagus, a tapering stomach, a tubular intestinal region, and a rectum, all of which have clinically normal shapes and conditions. VSI and HSI values fluctuate throughout the year, indicating the periodic variation of food content and availability in the ecosystem. The condition factor (K) was generally stable, with minor deviations in December. The mucosa, submucosa, muscularis, and serosa were identified from the stomach of N. nandus and showed normal histological characteristics. There were numerous proliferated villi in the tunica mucosa, but no histopathological abnormalities were found in the gut. These findings suggest that the current population of N. nandus in the Haor is in a favorable condition. However, local people reported some potential threats that might be a concern for the long-term survival of this species. The results of the present study will be useful for effective and sustainable stock management of the N. nandus fishery in the Kawadighi Haor and other floodplain ecosystems
An Internet of Things (IoT) based Smart Traffic Management System: A Context of Bangladesh
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