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Multimode interference in single mode-multimode-single mode fiber structure for steel beam compressive strain measurement
No full textA simple optical sensor based on singlemode-multimode-singlemode (SMS) optical fiber structure is proposed and demonstrated for the measurement of steel beam compression strain. The SMS sensor probe is fabricated by splicing both ends of a short multimode fiber with two pieces of standard single-mode fibers using a fusion splicer. The strain sensitivity stems from the difference in the effective refractive index of the core, which induces resonant wavelength shift against the strain. In the experiment, parallel measurements were also made using an electrical resistance (ER) strain gauge for comparison purpose. The SMS sensor was also able to detect the elastic limit of the steel beam from the abrupt shift in the interference wavelength as the compressive strain was increased above 5.351 mm/mm. The sensor showed that the steel beam had an elastic limit at a compressive load of 130 kN, which was in good agreement with the ER strain gauge measurement. Furthermore, the SMS sensor exhibited a compressive strain sensitivity of 0.0323 nm/kN from the initial load until it reached the elastic limit
The effectiveness of Realistic Mathematics Education approach: The role of mathematical representation as mediator between mathematical belief and problem solving
No full textThis study aims to identify the role of mathematical representation as a mediator between mathematical belief and problem solving. A quasi-experimental design was developed that included 426 Form 1 secondary school students. Respondents comprised 209 and 217 students in the treatment and control groups, respectively. SPSS 23.0, ANATES 4 and Amos 18 were used for data analysis. Findings indicated that mathematical representation plays a significant role as mediator between mathematical belief and arithmetic problem solving. The Realistic Mathematics Education (RME) approach successfully increased the arithmetic problem-solving ability of students
One-pot synthesis of palm oil-based polyester polyol for production of biodegradable and biocompatible polyurethane
No full textPalm oil-based polyester polyol was synthesized by reacting epoxidized palm olein with malonic acid under a convenient one-pot synthesis method. The optimum reaction time, temperature, and functionality molar ratio were determined. The optimal polyol consisted of hydroxyl and acid values of 98.19 and 1.44 mg KOH/g sample, 95% conversion of epoxides and Mn of 5201 Da; and the chemical structure was elucidated by Fourier transform infrared, Carbon-13 nuclear magnetic resonance (NMR), and 1H-NMR. The polyol was appeared as light-yellowish liquid with cloud and pour points of 12 and 10 °C and reacted with isophorone diisocyanate to produce polyurethane with interconnected pores ranged 35–2165 μm, porosity ranged 89–90%, tensile strength ranged 59–78 kPa, and compression stress ranged 48–55 kPa. The polyurethanes showed 120–260% water-uptake and controlled mass loss (1.6–15.3%) after 28 days of enzymatic degradation. PU 1 demonstrated slight cytotoxicity with cell proliferation and adhesion observed after 24 h incubation, demonstrated its potential as biomaterial for biomedical applications
The radiation shielding offered by the commercial glass installed in Bangladeshi dwellings
No full textOne sign of a vibrant Bangladeshi economy has been the move away from the use of more traditional housing materials towards a preference for modern constructional media. Glass, one such example, used both decoratively and in a structural context, offers various advantageous properties and facets including a protective feature against radiation that has not previously been considered. Current interest examines the dosimetric possibilities offered by the commercial glass as a secondary shield and also in retrospective ionising radiation exposure analysis. Four popular brands of window glass are investigated, all available within the local market (PHP-Bangladesh, Usmania-Bangladesh, Nasir-Bangladesh and Rider-China), all with the same thickness and colour, varying in terms of elemental weight fractions as evaluated by energy dispersive X-ray analysis. As potential attenuators of transmitted radiation thereby forming secondary barriers against radiation exposure from penetrating radiations, the four brands of glass have been studied using photon energies from 59 up to 1332 keV, a range of values representative of that potentially encountered in incidents. Use has been made of a well-shielded high-purity germanium γ-ray spectrometer and associated electronics, providing for evaluation of the characteristic barrier parameters of half-value layer, radiation protection efficiency and effective atomic number (Zeff). Of the four brands investigated, Rider provides superior secondary shielding performance. Concerning potential retrospective dosimetry the effective atomic number of the glass samples are comparable with that of the commercial thermoluminescence (TL) dosimeter TLD-200. At high doses, the TL yields are sufficient to provide for retrospective accident dosimetry
Non-tuned machine learning approach for hydrological time series forecasting
No full textStream-flow forecasting is a crucial task for hydrological science. Throughout the literature, traditional and artificial intelligence models have been applied to this task. An attempt to explore and develop better expert models is an ongoing endeavor for this hydrological application. In addition, the accuracy of modeling, confidence and practicality of the model are the other significant problems that need to be considered. Accordingly, this study investigates modern non-tuned machine learning data-driven approach, namely extreme learning machine (ELM). This data-driven approach is containing single layer feedforward neural network that selects the input variables randomly and determine the output weights systematically. To demonstrate the reliability and the effectiveness, one-step-ahead stream-flow forecasting based on three time-scale pattern (daily, mean weekly and mean monthly) for Johor river, Malaysia, were implemented. Artificial neural network (ANN) model is used for comparison and evaluation. The results indicated ELM approach superior the ANN model level accuracies and time consuming in addition to precision forecasting in tropical zone. In measureable terms, the dominance of ELM model over ANN model was indicated in accordance with coefficient determination (R2) root-mean-square error (RMSE) and mean absolute error (MAE). The results were obtained for example the daily time scale R2 = 0.94 and 0.90, RMSE = 2.78 and 11.63, and MAE = 0.10 and 0.43, for ELM and ANN models respectively
Lexicogrammatical Features in Japanese English: A Study of Five Speakers
No full textJapanese English (JE) refers to the English spoken by Japanese citizens. This paper characterizes JE by examining its lexicogrammatical features produced by five speakers participating in experimental recordings. Drawing on the initiatives taken by Cogo and Dewey's seminal work (2012), this study presents nine lexicogrammatical features which are taken to be typical of JE. It is shown that one decisive factor in creating a new variant is the formation of an alternative form to its native counterpart and this mechanism is sourced from the speaker's multiple knowledge about two languages
Predicting the Primitive Form of Rhombohedral Silicon Carbide (9R-SiC): A Pathway toward Polytypic Heterojunctions
No full textThe simplest form of rhombohedral silicon carbide is unknown. Previous studies of the elusive 9R-SiC have failed to show whether this polytype is stable as a bulk material. Here, we demonstrate that when molecular bonds along the c-axis of 2H-SiC are broken under tension, miniscule levels of stacking fault could give rise to the formation of 9R polytype and hence a Type II heterojunction. 9R-SiC has a very similar microscopic and crystallographic signature to that of 3C-SiC and 15R-SiC, respectively, which explains why it has evaded detection until now. Its vibrational footprint on the other hand is quite distinct thanks to its fewer active phonon modes. Surprisingly, the indirect band gap of this polytype is slightly wider than that of 2H-SiC, despite its lower hexagonality, and is equivalent to that of GaN. Due to its unique conduction band structure, 9R-SiC may also exhibit improved electron transport properties as compared to other SiC polytypes, and therefore could be suitable for high-frequency and high-voltage applications
A novel hybrid energy system combined with solar-road and soil-regenerator: Sensitivity analysis and optimization
No full textTo reduce the dependency of fossil fuels and greenhouse effect, the authors have proposed a novel solar-road and soil-regenerator hybrid energy system (SRSRHES), which utilizes a combination of Photovoltaic-Thermal (PVT) and soil heat storage technologies on the roadways. Design parameters and meteorological conditions affect the thermal storage performance of SRSRHES, which directly influences its annual performance and cost-effectiveness. Therefore, the study investigated the influence of flow rate, soil thermal properties, collector area, and borehole depth on electrical and thermal performance in three different cities with a numerical method to realize rational configuration of design parameters for the system. The results indicated that the recommended flow rates are 0.5, 0.3, and 0.3 kg/s in Beijing, Harbin, and Barkam respectively; Overall energy efficiency for different soils is different that is increased in the order of clay, sandy soil, sandstone, limestone, and granite. Collector area exerts a positive effect on total energy generation, but has a negative effect on overall energy efficiency. Borehole depth has a positive effect on both total energy generation and overall energy efficiency; Furthermore, the influence of various parameters on power generation performance is less than thermal storage performance, and overall energy efficiency mainly depend on thermal storage performance
The effectiveness of policy makers during uncertain environment: Evidence from a set of emerging market economies
Get PDFThis paper ascertain the effect of changes in the domestic interest rate on exchange rate movement, using monthly data from a set of emerging market economies. The central banks are responding to the exchange rate movements in addition to the other core variables, namely, inflation gap and the output gap. In addition, countries with a high degree of financial openness are more responsive to the movement in the exchange rate, but this has weakened the effectiveness of disinflationary policy. Policy makers should behave pre-emptive and necessitate the exchange rate adjustment as alternative policy choice, in the calculus of formulating policy rule
Glycaemic control in type 2 diabetic patients with chronic kidney disease: the impacts on enzymatic antioxidants and soluble RAGE
No full textBackground. Chronic kidney disease (CKD) is characterised by long-term kidney damage and renal function decline. Diabetic CKD is the principal subtype of kidney disease in Malaysia and is associated with oxidative stress which plays an important role in development and progression of the disease. Glycaemic control slows down the progression of diabetic complications, including diabetic CKD. However, the implication of glycaemic control on enzymatic antioxidants and solubleRAGE(sRAGE) in CKD patients remains elusive. The aim of this study was to investigate the effect of glycaemic control on the levels or activities of glutathione peroxidase (GPx), superoxide dismutase (SOD) and sRAGE in CKD patients. Methods. A total of 150 CKD patients and 64 non-CKD patients were enrolled. The type 2 diabetic patients in the recruited study participants were categorised based on their glycaemic control; poor glycaemic control (GC) with haemoglobin A1c (HbA1c) < 7% and good GC with HbA1c ≤ 7%. The levels or activities of GPx, SOD and sRAGE in plasma were measured. These biochemical parameters were analysed using Mann-Whitney U test and two-way analysis of variance (ANOVA). Results. The activities of GPx and SOD as well as plasma level of sRAGE were not significantly different among the CKD patients with varying glycaemic control status. Irrespective of diabetes status and glycaemic control status, CKD patients also exhibited lower plasma SOD activities compared with non-CKD patients. Among the non-CKD patients, SOD activities were significantly higher in diabetic patients with good GC than diabetic patients with poor GC. Two-way ANOVA revealed that both CKD status and glycaemic control had an interaction effect on SOD activities in diabetic subjects with and without CKD. Follow-up analysis showed that SOD activities were significantly higher in non-CKD patients with good GC. There were no overall significant differences in GPx activities among the study participants. Furthermore, plasma sRAGE levels were higher in diabetic patients with CKD than those without CKD, regardless of glycaemic control status. There were no interaction effects between CKD status and glycaemic control status on GPx and sRAGE. Instead, CKD status showed significant main effects on these parameters, indicating significant differences between diabetic subjects with CKD and diabetic subjects without CKD. Conclusion. Glycaemic control did not quantitatively alter GPx, SOD and sRAGE in diabetic CKD patients. Despite the advantages of good glycaemic control, a well-controlled diabetes in CKD did not modulate the activities of enzymatic antiox- idants and sRAGE levels, therefore may not be the primary mechanism to handle oxidative stress