19672 research outputs found
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Microstructural characterization and mechanical properties of bottom ash mortar
No full textCoal Bottom Ash (CBA) is one of the widely-produced residues of coal incineration in thermal power plants. The annual extraction of such a huge amount of waste needs a massive transfer field, which constitutes a threat to the environment. However, the utilization of such residue as a fine aggregate in concrete can be an environmentally-friendly opportunity. Hence, the main purpose of this paper is to evaluate the microstructure and mechanical properties of the usage of BA as a fine aggregate replacement in mortar mixtures. It is observed that BA has a reactive fraction with pozzolanic characteristics. This provides stronger mortar when a medium volume of the material (up to 40%) is substituted. In addition, the CBA based mixture can be classified as lightweight concrete. The compressive strength value of the specimen using 40% CBA at 56 days was 55 MPa, which reached the same strength limit of control mortar mixture
The role of electrolyte fluidity on the power generation characteristics of thermally driven electrochemical cells
No full textThermally driven electrochemical cells (thermocells) are able to convert thermal gradient applied across redox electrolyte into electricity. The performance of the thermocells heavily depends on the magnitude and integrity of the applied thermal gradient. Herein, we study the iodide/triiodide (I-/I3-) based 1-Ethyl-3-methyl-imidazolium Ethylsulfate ([EMIM][EtSO4]) solutions in a thermocell. In order to comprehend the role of fluidity of the electrolyte, we prepared set of solutions by diluting [EMIM][EtSO4] with 0.002, 0.004, and 0.010 mol of Acetonitrile (ACN). We realized a significant improvement in ionic conductivity (σ) and electrochemical Seebeck (Se) of diluted electrolytes as compared to base [EMIM][EtSO4] owing to the solvent organization. However, the infra-red thermography indicated faster heat flow in ACN-diluted-[EMIM] [EtSO4] as compared to the base [EMIM][EtSO4]. Therefore, the maximum power density of base [EMIM][EtSO4] (i.e. 118.5 μW.m-2) is 3 times higher than the ACN-diluted-[EMIM][EtSO4] (i.e. 36.1 μW.m-2) because of the lower thermal conductivity. Hence this paper illustrates the compromise between the fast mass/flow transfer due to fluidity (of diluted samples) and the low thermal conductivity (of the pure [EMIM][EtSO4])
Passive mode-locking of ytterbium-doped fiber laser using chemically exfoliated graphene as saturable absorber
No full textAn all-fiber passively mode-locked Ytterbium-doped fiber laser (YDFL) was demonstrated by using a chemically exfoliated graphene as saturable absorber (SA). The obtained graphene flakes were embedded into a PEO polymer to provide a modulation depth of 16.2 % and incorporated into an YDFL cavity to generate ultrafast fiber laser operating at 1052.9 nm. The laser generated stable soliton pulses with repetition rate of 4.5 MHz and the estimated minimum pulse width of 0.14 ps. The pulse energy of 1.5 nJ was obtained at the maximum pump power of 203.5 mW. This result indicates that the chemically exfoliated graphene is a promising means for mode-locked fiber lasers
Does religious obligation of Muslims inwestern China influence their intention to adopt Islamic banking?
No full textWith a total number of 23 million Chinese Muslims, the Islamic banking service in China is still at its early stage of development. This study seeks to examine the factors that influence the Chinese Muslims' intentions to adopt Islamic banking. Employing the theory of planned behaviour (TPB), the present study investigates the effects of attitude, subjective norms, perceived behavioural control and religious obligation on the intention to adopt Islamic banking services amongst the Chinese Muslims. The survey data used in the process of research was collected from 669 Muslim respondents across four major cities in the western regions of China. The hypothesized relationships are examined by using the Structural Equation Modeling(SEM). The results show that attitude, subjective norms, perceived behaviour control,and religious obligation significantly influence the intention to adopt Islamic banking among the Chinese Muslims
Synthesis and characterisation of highly branched polyisoprene: exploiting the “Strathclyde route” in anionic polymerisation
No full textThis work aimed at developing a synthetic route towards highly branched poly(isoprene) from commercially available raw materials, in good yield and devoid of microgelation, i.e., to prepare a completely soluble polymer via the versatile technique anionic polymerisation. The polymerisations were conducted under high vacuum conditions using sec-butyllithium as initiator at 50 °C in toluene. Toluene served both as a solvent and as a chain-Transfer agent. The polar modifier used was tetramethylethylenediamine (TMEDA), and a commercial mixture of divinylbenzene (DVB) was employed as the branching agent for the "living" poly(isoprenyl)lithium anions. The nature of the reaction was studied on the TMEDA/Li ratio as well as the DVB/Li ratio. The obtained branched polymers were characterised by triple detection size exclusion chromatography (SEC), proton nuclear magnetic resonance spectroscopy (1H NMR), differential scanning calorimetry (DSC) and melt rheology. Broad molecular weight distributions have been obtained for the highly branched polymer products. 1H NMR spectroscopy reveals the dominance of 3,4-polyisoprene microstructure. It was found that the complex viscosities and dynamic moduli of the branched samples were much lower compared to their linear counterparts. The results conform with earlier findings by the "Strathclyde team" for radical polymerisation systems. This methodology has the potential of providing soluble branched vinyl polymers at low cost using the readily available raw materials
Anti-Inflammatory, Antiapoptotic and Proproliferative Effects of Vitis vinifera Seed Ethanolic Extract in the Liver of Streptozotocin-Nicotinamide-Induced Type 2 Diabetes in Male Rats
No full textObjectives: Consumption of Vitis vinifera seed has been reported to ameliorate liver pathology in diabetes mellitus; however, the mechanisms underlying its effects remain unknown. In this study, the anti-inflammatory, anti-apoptotic and pro-proliferative effects of the ethanolic seed extract of V. vinifera (VVSEE) in the liver in cases of diabetes were identified. Methods: Adult male rats with streptozotocin-nicotinamide-induced diabetes were given 50, 100 or 200 mg/kg body weight VVSEE orally for 28 days. At the end of the treatment, body weights were determined, and the blood was collected for analyses of fasting blood glucose, insulin and liver enzyme levels. Following sacrifice, livers were harvested and their wet weights and glycogen contents were measured. Histologic appearances of the livers were observed under light microscopy, and the expression and distribution of inflammatory, apoptosis and proliferative markers in the livers were identified by molecular biologic techniques. Results: Treatment of rats with diabetes by VVSEE attenuates decreased body weight, liver weight and liver glycogen content. Additionally, increases in fasting blood glucose levels and liver enzyme levels and decreases in serum insulin levels were ameliorated. Lesser histopathologic changes were also observed: decreased inflammation and apoptosis, as indicated by decreased levels of inflammatory markers (TNF-α, NF-Kβ, IKK-β, IL-6, IL-1β) and apoptosis markers (caspase-3, caspase-9 and Bax). VVSEE treatment induces increase in hepatocyte regeneration, as indicated by increased PCNA and Ki-67 distribution in the livers of rats with diabetes. Several molecules identified in VVSEE via gas chromatography mass spectrometry might contribute to these effects. Conclusions: The anti-inflammatory, anti-apoptotic and pro-proliferative effects of VVSEE could account for its hepatoprotective actions in diabetes
Seismic Response Analysis of Fully Base-Isolated Adjacent Buildings with Segregated Foundations
No full textIn populous cities, construction of multistorey buildings close to each other due to space limitation and increased land cost is a dire need. Such construction methods arise several problems during earthquake excitation. The aim of this study is to investigate the bidirectional seismic responses of fully base-isolated (FBI) adjacent buildings having different heights and segregated foundations. Therefore, two scenarios, namely, (a) investigation of the responses of FBI adjacent buildings compared to those with fixed base (FFB) and (b) the effects of separation distance on FBI adjacent buildings, were studied. Based on these investigations, the results showed that isolation system significantly enhances the overall responses of the BI buildings. Spectacularly, the base isolation system was further efficient to decrease displacement rather than the acceleration. In addition, increase of the seismic gap changed the acceleration, pounding, base shear, base moment, and storey drift, as well as the force-deformation performance of the isolators. Therefore, it seems a need to focus on the effect of the separation distances for the design of base isolators for FBI adjacent buildings in future works
Exports and economic growth in Sub-Saharan Africa: New insights from innovative econometric methods
No full textThis study examined the relationship between exports and economic growth in Sub-Saharan Africa. It employed innovative econometric methods, including the Fourier ADF with structural break test, a comparative analysis of three causality tests and a rolling causality test procedure. The findings suggested that there was a statistically significant relationship between exports and economic growth in several Sub-Saharan countries. However, the causal linkages between exports and economic growth in these countries were found to be weak and unstable. These empirical results have some notable policy implications
Arsenic removal from water using N,N-diethylethanolammonium chloride based DES-functionalized CNTs: (NARX) neural network approach
No full textIn this paper, the deep eutectic solvent-functionalized carbon nanotube was used for arsenic removal from water solution. The adsorbent used was characterized using Raman spectroscopy, Fourier transform infrared (FTIR) and zeta potential. The effect of the parameters (adsorbent dosage, pH, initial concentration and contact time) was studied to find the optimum conditions for maximum adsorption capacity of the functionalized carbon nanotube. The pseudo-second-order, the pseudo first-order and intraparticle diffusion kinetic models were applied to identify the adsorption rate and mechanism, the pseudo-second-order model best described the adsorption kinetics of the system. The non-linear autoregressive network with exogenous inputs (NARX) neural network strategy was used for the modelling and predicting of the adsorption capacity of functionalized carbon nanotube. Different indicators were used to determine the efficiency and accuracy of the NARX neural network model which were mean square error (MSE), root mean square error (RMSE), relative root mean square error (RRMSE) and mean absolute percentage error (MAPE). The sensitivity study of the used parameters in the experimental work was completed. Comparison of the NARX model results with the experimental data confirmed that the NARX model was able to predict the arsenic removal from water
Sustainability of additive-doped biodiesel: Analysis of its aggressiveness toward metal corrosion
No full textThe recent shortage of fossil fuel sources and the growing environmental concerns have considerably affected the necessity to search for alternative energy sources. The tremendous increase in energy demands in the transportation and industrial sectors has strengthened efforts to identify sustainable alternative fuel sources. In this regard, biodiesel can be considered a promising substitute for diesel. However, biodiesel is corrosive when it comes in contact with metals. The present study aims at investigating the sustainability of additive-doped biodiesel upon exposure of copper-based materials. A static immersion test was conducted at room temperature (25 °C–27 °C) for 2160 h. The metals used in the experiment were copper, leaded bronze, and phosphorous bronze. The investigated fuel was 100% palm biodiesel without and with additives (500 ppm), including tert-butylamine, benzotriazole, propyl gallate, pyrogallol, and butylated hydroxytoluene. The corrosion rate of the metals was determined at the end of the experiment via weight loss measurement. The metals were further characterized via scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction analysis. Results showed that the corrosion rate of copper was considerably higher than those of the other metals. X-ray diffraction analysis indicated the presence of copper carbonate and cupric oxide on the copper surface that was exposed to biodiesel. The occurrence of these compounds could be attributed to the high concentrations of carbon dioxide and oxygen in the biodiesel when additive was absent. Gas chromatography–mass spectrometry data showed that the unsaturated molecules in biodiesel could reduce the sustainability of metals upon exposure to biodiesel. However, metal surface degradation was significantly reduced in the presence of additives. In particular, benzotriazole and tert-butylamine considerably improved the sustainability of biodiesel by limiting metal surface degradation