86 research outputs found

    Characteristics of plates embedded with shape memory alloy wires

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    Shape memory alloy (SMA) has the potential to be used in engineering applications. It is widely used as sensors, actuators, dampers and when embedded into composite, it demonstrates some unique mechanical and vibration properties such as the strength and damping of the composite material. In this research, the thermo�mechanical properties of SMA wire, the mechanical properties and vibration characteristics of composites embedded SMA wire were determined. There are two groups of SMA arrangement in the composite to be fabricated; they are without SMA wire and with unidirectional fine SMA wires (Flexinol® wire) oriented at 0°, 15°, 30° and 45° with the volume fraction of 0.08. The characteristics of SMA wire were determined using the Universal Testing Machine. The Young's modulus, stress - strain curve analysis, fundamental frequency at first mode and damping behavior of the SMA embedded composite were also done. Simulation was carried out using MA TLAB based on Brinson model and Reddy approach. The results showed that Flexinol® wire has the phase transformation temperatures at 32.840 C, 44.78°C, 52.540 C and 60.900 C and it agree well with the manufacturer technical data. The Flexinol® wire has Young's modulus during martensite and austenite of33.16 GPa and 69.59 GPa and the coefficient of stress influence during martensite and austenite of 10.76 MPa/°C and 9.08 MP~C. The Young's modulus of the composite is linearly proportional to temperature increment. The maximum fundamental frequency shifted occur at 45° for the boundary condition of C-F -F -F and C-F -C-F while for the boundary condition of C-C-C-C were at 15°, 75°, 105° and 165° if compared with the fundamental frequency at 0°. The overall highest damping occurred when 0.50 A with DC applied at the boundary condition ofC�F-F-F

    Development of Low Wind Speed Anemometer

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    Anemometer is a measuring device used to measure the wind speed of an area. Before design or installing a wind turbine, it is important to determine the average wind speed of that particular area throughout the year. But it is illogically to purchase anemometer to measure the wind velocity for a year period. The purpose of this project is to design and fabricate a small scale of anemometer which will able to give the wind velocity with an acceptable range of uncertainty. The fabrication of the anemometer is developed using design methodology and simulation to obtain the optimized design. The designed anemometer has the mean absolute percentage error (MAPE) of 3.23 % when compared with Dwyer series 471 thermo-anemometer

    Investigation of Water Hammer Effect Through Pipeline System

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    This paper we study the condition where the water hammer effect is occurs in pipe line. Water hammer can cause the pipe to break if the pressure is high enough. The experiment will be set-up to investigate the water hammer effect in order to avoid the water hammer effect happen. The prevention of water hammer effect will be propose and prove the prevention method is successfully reduce the water hammer effect. The prevention method using is installing the bypass pipe with non-return valve. The experiment is done by capture the vibration signal by using data acquisition device and accelerometer. The pressure signal is capture after a sudden shutoff for the valve. The signal is than analyze and convert to wave speed. The project is differentiating and compares the water hammer phenomenon with different pipe material, pipe length, inlet diameter of pipe, and pressure in pipeline. From the experiment, result shown that the lower strength material pipe, smaller inlet diameter pipe, and longer pipe will deal with lager water hammer effect. Besides, the prevention method by installing by pass pipe with non-return valve of water hammer effect is proved successfully reduce the water hammer phenomenon by 33.33% of pressure

    Utilization of waste hydraulic oil as fuel in diesel engine

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    Production of alternative diesel fuel has been increasing drastically in many Asian countries. Since the reduction of petroleum production by Organization of Petroleum Exporting Countries (OPEC), the research on alternative fuel for diesel engine has gain interest. The target of this project is to substitute some percentage usage of conventional diesel fuel with waste substance without compromising on engine performance and exhaust emissions. This study has produced two type of alternative fuels. A test fuel consisting 30% of water into diesel fuel with the existence of additive or emulsifier (span 80) is called as DW Emul. Another test fuel which is named as DHW Emul produced by blending 30% of water into a mixture consisting of 20% of waste hydraulic oil and 80% of diesel fuel with the existence of span 80. The engine performance and exhaust emissions of DW Emul and DHW Emul are measured and has been compared with the conventional diesel fuel. A 600cc single cylinder direct injection diesel engine was used. The experiment was conducted at 1500 rpm with variable engine loads. Results show that DHW Emul and DW Emul has higher brake specific fuel consumption (BSFC). However, by considering the total use of diesel fuel contained in DW Emul, the quantity was lower at all loads. The same goes for DHW Emul at low load but deteriorate at high load which show slightly higher compared with of using 100% conventional diesel fuel. DHW Emul has suppressed CO emission that is usually high of using emulsion fuel to the level similar to conventional diesel fuel. NOx and Smoke emissions for DHW Emul are lower than conventional diesel. The use of DHW Emul can give significant reduction of NOx and Smoke emissions without deterioration of CO emission

    Bioactivity, physical and chemical properties of MTA mixed with propylene glycol

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    AbstractObjective To investigate the physical (setting time, hardness, flowability, microstructure) and chemical (pH change, calcium release, crystallinity) properties and the biological outcomes (cell survival and differentiation) of mineral trioxide aggregate (MTA) mixed using different proportions of propylene glycol (PG) and water.Material and Methods White MTA was mixed with different water/PG ratios (100/0, 80/20 and 50/50). Composition (XRD), microstructure (SEM), setting time (ASTM C266-13), flowability (ANSI/ADA 57-2000), Knoop hardness (100 g/10 s) and chemical characteristics (pH change and Ca2+ release for 7 days) were evaluated. Cell proliferation, osteo/odontoblastic gene expression and mineralization induced by MTA mixed with PG were evaluated. MTA discs (5 mm in diameter, 2 mm thick) were prepared and soaked in culture medium for 7 days. Next, the discs were removed and the medium used to culture dental pulp stem cells (DPSC) for 28 days. Cells survival was evaluated using MTS assay (24, 72 and 120 h) and differentiation with RT-PCR (ALP, OCN, Runx2, DSPP and MEPE) and alizarin red staining (7 and 14 days). Data were analysed using one-way ANOVA and Tukey’s post-hoc analysis (a=0.05).Results The addition of PG significantly increased setting time, flowability and Ca2+ release, but it compromised the hardness of the material. SEM showed that 50/50 group resulted porous material after setting due to the incomplete setting reaction, as shown by XRD analysis. The addition of PG (80/20 and 50/50) was not capable to improve cell proliferation or to enhance gene expression, and mineralized deposition of DPSC after 7 and 14 days as compared to the 100/0.Conclusion Except for flowability, the addition of PG did not promote further improvements on the chemical and physical properties evaluated, and it was not capable of enhancing the bioactivity of the MTA

    An application of cadastral fabric system in improving positional accuracy of cadastral databases in Malaysia

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    Cadastral fabric is perceived as a feasible solution to improve the speed, efficiency and quality of the cadastral measurement data to implement Positional Accuracy Improvement (PAI) and to support Coordinated Cadastral System (CCS) and Dynamic Coordinated Cadastral System (DCCS) in Malaysia. In light of this, this study aims to propose a system to upgrade the positional accuracy of the existing cadastral system through the utilisation of the cadastral fabric system. A comprehensive investigation on the capability of the proposed system is carried out. A total of four evaluation aspects is incorporated in the study to investigate the feasibility and capability of the software, viz. performance of geodetic least squares adjustment, quality assurance techniques, supporting functions, and user friendliness. This study utilises secondary data obtained from the Department of Surveying and Mapping Malaysia (DSMM). The test area is coded as Block B21701 which is located in Selangor, Malaysia. Results show that least square adjustment for the entire network is completed in a timely manner. Various quality assurance techniques are implementable, namely error ellipses, magnitude of correction vectors and adjustment trajectory, as well as inspection of adjusted online bearings. In addition, the system supports coordinate versioning, coordinates of various datum or projection. Last but not least, user friendliness of the system is identified through the software interface, interaction and automation functions. With that, it is concluded that the proposed system is highly feasible and capable to create a Cadastral Fabric to improve the positional accuracy of existing cadastral system used in Malaysia

    Gut Microbiome of a Multiethnic Community Possessed No Predominant Microbiota

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    With increasing globalisation, various diets from around the world are readily available in global cities. This study aimed to verify if multiethnic dietary habits destabilised the gut microbiome in response to frequent changes, leading to readily colonisation of exogenous microbes. This may have health implications. We profiled Singapore young adults of different ethnicities for dietary habits, faecal type, gut microbiome and cytokine levels. Subjects were challenged with Lactobacillus casei, and corresponding changes in microbiome and cytokines were evaluated. Here, we found that the majority of young adults had normal stool types (73% Bristol Scale Types 3 and 4) and faecal microbiome categorised into three clusters, irrespective of race and gender. Cluster 1 was dominated by Bacteroides, Cluster 2 by Prevotella, while Cluster 3 showed a marginal increase in Blautia, Ruminococaceae and Ruminococcus, without a predominant microbiota. These youngsters in the three faecal microbiome clusters preferred Western high sugary beverages, Southeast Asian plant-rich diet and Asian/Western diets in rotation, respectively. Multiethnic dietary habits (Cluster 3) led to a gut microbiome without predominant microbiota yet demonstrated colonisation resistance to Lactobacillus. Although Bacteroides and Prevotella are reported to be health-promoting but also risk factors for some illnesses, Singapore-style dietary rotation habits may alleviate Bacteroides and Prevotella associated ill effects. Different immunological outcome was observed during consumption of the lactobacilli among the three microbiome clusters.</p

    Atrasentan and renal events in patients with type 2 diabetes and chronic kidney disease (SONAR): a double-blind, randomised, placebo-controlled trial

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    Background: Short-term treatment for people with type 2 diabetes using a low dose of the selective endothelin A receptor antagonist atrasentan reduces albuminuria without causing significant sodium retention. We report the long-term effects of treatment with atrasentan on major renal outcomes. Methods: We did this double-blind, randomised, placebo-controlled trial at 689 sites in 41 countries. We enrolled adults aged 18–85 years with type 2 diabetes, estimated glomerular filtration rate (eGFR)25–75 mL/min per 1·73 m 2 of body surface area, and a urine albumin-to-creatinine ratio (UACR)of 300–5000 mg/g who had received maximum labelled or tolerated renin–angiotensin system inhibition for at least 4 weeks. Participants were given atrasentan 0·75 mg orally daily during an enrichment period before random group assignment. Those with a UACR decrease of at least 30% with no substantial fluid retention during the enrichment period (responders)were included in the double-blind treatment period. Responders were randomly assigned to receive either atrasentan 0·75 mg orally daily or placebo. All patients and investigators were masked to treatment assignment. The primary endpoint was a composite of doubling of serum creatinine (sustained for ≥30 days)or end-stage kidney disease (eGFR <15 mL/min per 1·73 m 2 sustained for ≥90 days, chronic dialysis for ≥90 days, kidney transplantation, or death from kidney failure)in the intention-to-treat population of all responders. Safety was assessed in all patients who received at least one dose of their assigned study treatment. The study is registered with ClinicalTrials.gov, number NCT01858532. Findings: Between May 17, 2013, and July 13, 2017, 11 087 patients were screened; 5117 entered the enrichment period, and 4711 completed the enrichment period. Of these, 2648 patients were responders and were randomly assigned to the atrasentan group (n=1325)or placebo group (n=1323). Median follow-up was 2·2 years (IQR 1·4–2·9). 79 (6·0%)of 1325 patients in the atrasentan group and 105 (7·9%)of 1323 in the placebo group had a primary composite renal endpoint event (hazard ratio [HR]0·65 [95% CI 0·49–0·88]; p=0·0047). Fluid retention and anaemia adverse events, which have been previously attributed to endothelin receptor antagonists, were more frequent in the atrasentan group than in the placebo group. Hospital admission for heart failure occurred in 47 (3·5%)of 1325 patients in the atrasentan group and 34 (2·6%)of 1323 patients in the placebo group (HR 1·33 [95% CI 0·85–2·07]; p=0·208). 58 (4·4%)patients in the atrasentan group and 52 (3·9%)in the placebo group died (HR 1·09 [95% CI 0·75–1·59]; p=0·65). Interpretation: Atrasentan reduced the risk of renal events in patients with diabetes and chronic kidney disease who were selected to optimise efficacy and safety. These data support a potential role for selective endothelin receptor antagonists in protecting renal function in patients with type 2 diabetes at high risk of developing end-stage kidney disease. Funding: AbbVie
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