19672 research outputs found
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Technical data-driven tool condition monitoring challenges for CNC milling: a review
No full textCNC milling is a highly complex machining process highly valued in various industries, including the automotive and aerospace industries. With the increasing competition, manufacturers are aiming to keep maintenance costs low while ensuring high levels of manufacturing equipment reliability. It is also highly important for them to maximize the service life of each cutting tool by avoiding premature replacements while minimizing the risks of scrap due to tool breakage. This calls for the need for a condition-based maintenance approach and more powerful, flexible and robust tool condition monitoring (TCM) techniques with minimal reliance on subjective diagnosis based on the expert knowledge. This paper discusses the technical aspects of recent developments in state-of-the-art TCM techniques and current challenges which limit the viability of TCM in real-life industrial applications. The technical challenges in modern TCM were split into two major groups of problems: (1) challenges in data processing and (2) issues regarding tool wear model performance. Current methodologies to overcome issues in each of the sections in this paper are discussed and, where possible, compared to highlight their respective advantages and disadvantages. Finally, this paper concludes with a discussion on possible trends in TCM development and interesting avenues for future research. © 2020, Springer-Verlag London Ltd., part of Springer Nature
The effects of age on clinical characteristics, hospitalization and mortality of patients with influenza‐related illness at a tertiary care centre in Malaysia
No full textBackground: Age is an established risk factor for poor outcomes in individuals with influenza-related illness, and data on its influence on clinical presentations and outcomes in the South-East Asian settings are scarce. The aim of this study was to determine the above among adults with influenza-related upper respiratory tract infection at a teaching hospital in Malaysia. Methods: A retrospective case-note analysis was conducted on a cohort of 3935 patients attending primary care at the University Malaya Medical Centre, Malaysia from February 2012 till May 2014 with URTI symptoms. Demographics, clinical characteristics, medical and vaccination history were obtained from electronic medical records, and mortality data from the National Registration Department. Comparisons were made between those aged <25, ≥25 to <65 and ≥65 years. Results: 470 (11.9%) had PCR-confirmed influenza virus infection. Six (1.3%) received prior influenza vaccination. Those aged ≥65 years were more likely to have ≥2 comorbidities (P <.001) and were less likely to present with fever (P =.004). One-third of those aged ≥65 years experienced hospitalization, intensive care admission or death within a year compared to 10% in the ≥25 to <65 years. Age ≥65 years was an independent predictor of hospitalization and death (OR = 9.97; 95% CI = 3.11-31.93) compared to those aged <25 years. Conclusion: Older patients in our cohort were more likely to have comorbidities and present with atypical features, with older age being an independent predictor of poor health outcomes. Our findings will now inform future health policies on older persons and economic modelling of adult vaccination programmes. © 2019 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd
Diagnosis of severe dengue: Challenges, needs and opportunities
No full textBackground: Delayed diagnosis of dengue cases with increased risk for severe disease could lead to poor disease outcome. To date there is no specific laboratory diagnostic test for severe dengue. This qualitative study explored expert views regarding current issues in diagnosing severe dengue, rationale for severe dengue-specific diagnostics, future prospects and features of potential diagnostics for severe dengue. Methods: In-depth individual interviews with thematic saturation were conducted between May and July 2018. The data was analyzed using thematic analysis. Results: Based on expert opinion, diagnosis of severe dengue is challenging as it depends on astute clinical interpretation of non-dengue-specific clinical and laboratory findings. A specific test that detects impending manifestation of severe dengue could 1) overcome failure in identifying severe disease for referral or admission, 2) facilitate timely and appropriate management of plasma leakage and bleeding, 3) overcome the lack of clinical expertise and laboratory diagnosis in rural health settings. The most important feature of any diagnostics for severe dengue is the point-of-care (POC) format where it can be performed at or near the bedside. Conclusion: The development of diagnostics to detect impending severe dengue is warranted to reduce the morbidity and mortality rates of dengue infection and it should be prioritized. © 2020 The Author
The study of seroprevalence of hepatitis E virus and an investigation into the lifestyle behaviours of the aborigines in Malaysia
No full textMalaysia is a non-endemic country for hepatitis E virus (HEV) infection. However, seroprevalence as high as 50% among samples of aboriginal people were reported over two decades ago. A total of 207 samples collected from seven aboriginal villages in rural settlements across two states in Malaysia were analysed for anti-HEV IgG and IgM by an enzyme-linked immunoassay. Following the detection of anti-HEV seroprevalence, we organized health outreach to inform and educate the community. Qualitative interviews were conducted with individuals tested positive for anti-HEV antibodies. Data derived from interviews and observations were used to investigate possible lifestyle behaviours associated with HEV infection. Anti-HEV IgG was detected in six samples (5.9%) from the village of Dusun Kubur. Qualitative inquiry and observation study revealed poor dietary and household hygiene, contaminated food and water, contact with animal faeces, unsanitary and domestic waste disposal, and wildlife reservoirs could be the contributing factors for transmission and acquisition of HEV infection. Investigation during health outreach is important to provide insights for future empirical research and implementation for improvement of lifestyle behaviours among the aborigines. Managing the risk of HEV infection in the aborigines may reduce the risk of HEV transmission to the local communities. © 2020 Blackwell Verlag Gmb
Trace Level Detection of Bisphenol A Analogues and Parabens by LC-MS/MS in Human Plasma from Malaysians
No full textIn this study, a novel LC-MS/MS method was designed using a simple extraction procedure that was scientifically developed to capture the most relevant bisphenol A (BPA) analogues (BPB, BPF, BPS, and BPAF) and parabens (propylparaben, ethylparaben, butylparaben, and methylparaben) in human plasma. The LC-MS/MS method was validated using US FDA guidelines, and all validation requirements were satisfactory. This is the method that allows for the detection of plasma bisphenols and parabens in one run and is also the fastest BPA analogue and paraben detection technique for human plasma. The method was used to analyze samples from 150 healthy volunteers from Malaysia who enrolled in the study. No BPB was detected in any of the volunteers; however, 99.3% were positive for BPF. Only 24% and 10.7% of volunteers were positive for BPAF and BPS, respectively. A high percentage of volunteers were negative for propylparaben, ethylparaben, butylparaben, and methylparaben (56%, 68%, 86.7%, and 83.3%, respectively). These results suggest that persons in Malaysia are exposed to different BPA analogues and parabens, from both the daily use of products (cosmetic and plastic products) and the environment. © 2020 Idha Arfianti Wiraagni et al
A novel peak shaving algorithm for islanded microgrid using battery energy storage system
No full textThe objective of this study is to propose a decision-tree-based peak shaving algorithm for islanded microgrid. The proposed algorithm helps an islanded microgrid to operate its generation units efficiently. Effectiveness of the proposed algorithm was tested with a BESS-based MATLAB/Simulink model of an actual microgrid under realistic load conditions which were recorded. To evaluate the performance, simulation case studies were conducted under various load conditions and results were compared with conventional techniques. Results showed that the proposed algorithm offers a simple and effective way of peak load shaving without heavy computational burdens often needed in other methods. The comparison analysis verified that the proposed algorithm can effectively mitigate the peak load demand regardless of the schedule of the generators, where conventional methods were limited. The financial benefit investigation shows that microgrid utility can enjoy substantial savings, while reducing of the peak demand of the microgrid. Thus, the islanded microgrid that include fuel-based generation can implement the proposed technique to reduce the consumption of fuel and increase the efficiency of fuel-based generation through peak load mitigation. © 2020 Elsevier Lt
Prevalence of Bacillus cereus s.l. in ultra-high temperature chocolate milk from selected milk manufacturers in Malaysia
No full textBacillus cereus is a major foodborne pathogen of great concern to the dairy industry owing to its resilient spores as well as the adverse effect of its toxins. At present, there is no informational study available to solve or pinpoint the UHT chocolate milk contamination issue in Malaysia. This work aimed to investigate the prevalence and contamination level of B. cereus s.l. in UHT chocolate milk and to suggest the appropriate solution for the issue. In the present study, B. cereus s.l. prevalence and contamination level in individually packed UHT chocolate milk from processing factories was evaluated. The prevalence and concentration of B. cereus s.l. were determined via MPN-PCR (Most Probable Number-Polymerase Chain Reaction) assay. Results showed that 31.11% from 220 of UHT chocolate milk tested contained Bacillus spp.; of this Bacillus spp. positive samples, 24.30% were also positive for B. cereus s.l. with concentration ranging from less than 3 to more than 1100 MPN/mL. Findings from this study highlighted the possibility of UHT chocolate milk as a potential source of B. cereus s.l. infection. Therefore, findings emphasized the needs to revise, monitor and improve UHT sterilization process to reduce infection risk. Furthermore, it is also essential to maintain the hygiene to minimize initial microbial load and contamination of UHT chocolate milk, beginning from production to retail. © 2020 The Authors. Published by Rynnye Lyan Resources
Optical features of novel semiconducting crystals Tl1–xGa1–xSnxSe2 (x=0.05; 0.1)
No full textThe results of the novel Tl1–xGa1–xSnxSe2 single crystals (x = 0.05; 0.1) growth together with complex studies of their optical, electric and photoelectric properties are presented. Semiconductor crystalline alloys Tl2Sе, Ga(In)2Sе3, SnSе2 possessing congruent melting features has been served as components for the quasi-ternary systems. The Tl2Se–Ga2Se3 was melted congruently at temperature 1073 K. Two compounds existied for the Tl2Sе–In2Sе3system: TlInSe2 melting congruently at 1023 K, and Tl2Sе–In2Sе3 within congruent melting nature at 1029 K. Isothermal section of the Tl2Se–Ga2Se3–SnSe2 system at 520 K have been constructed from X-ray phase and formation of the ternary compounds Tl4SnSе4, Tl2SnSе3, TlGaSе2 was confirmed. The spectral dependences of the absorption coefficients near the fundamental absorption have been studied with respect to direct as indirect dipole allowed inter-band transitions realized in the (TlGaSe2)1-x(SnSe2)x crystals for the studied temperature range. Follwing the Urbach's energy the role of electron-phonon interaction and structural disorder was analyzed. © 2019 Elsevier Gmb
RSM optimization of microwave pyrolysis parameters to produce OPS char with high yield and large BET surface area
No full textMicrowave pyrolysis is a very effective technique to convert organic waste into energy rich products. In the present work micro porous and carbonaceous OPS char was synthesized by microwave pyrolysis technique. OPS char yield and its BET surface area was investigated as a function of process parameters to make the microwave pyrolysis of OPS more efficient. Both of these quantities were found to be affected by the process parameters. With the rise in microwave power (MWP) and radiation time (RT), OPS char yield was lowered while increase N2 flow rate (NFR) increased the OPS char yield slightly. Extreme values of either of the process parameter was seen to lower the BET surface area of OPS char. Response Surface Methodology (RSM), was used to optimize the process parameters for maximized OPS char yield and its BET surface area. Regression models for the OPS char yield and its BET surface area were also developed in this study. These regression models were having high Fischer test value & lower p-value which ensure its reliability and applicability. ANOVA analysis of the experimental data provided the process parameters to achieve maximized OPS char yield (60.93%) and BET surface area (250.03 m2/g). The predicted results were validated and it was found that the experimental data varied only by 5.99% in yield and 6.34% in BET surface area from the predicted values. © 2020 Elsevier Lt
Performance of mycelial biomass and exopolysaccharide from Malaysian Ganoderma lucidum for the fungivore red hybrid Tilapia (Oreochromis sp.) in Zebrafish embryo
No full textNatural mycelial biomass (MB) and extracted exopolysaccharide (EPS) from the pre-grown Malaysian Ganoderma lucidum mushroom are both considered as high-end materials due to their high commercial value in the aquaculture industry. To evaluate their potential toxicity as a fish-feed supplement for the fungivore red hybrid Tilapia (Oreochromis sp.), both MB (250−5000 μg/mL) and EPS (62.5−3000 μg/mL) were subjected to zebrafish embryo toxicity (ZFET) assay, and the effects on zebrafish embryos (ZE) early development were analyzed between 24−120 hours of post-exposure (HPE). MB and EPS showed no toxic effect towards the ZE with LC50 of 1650 μg/mL and 2648.38 μg/mL, respectively. MB at concentrations between 250−5000 μg/mL and EPS at 3000 μg/mL showed no significant changes in ZE hatching. No significant changes in the ZE heart rate were detected following treatment with both tested compounds (MB: 250−2000 μg/mL and EPS: 62.5−3000 μg/mL) as compared to untreated embryos (135.5 beats/min). Furthermore, teratogenic effects of both MB and EPS (<3000 μg/mL) on zebrafish embryonic development were not observed. Together, both natural compounds MB and EPS can be considered non-toxic, suggesting that these can be safely applied as feed substances in the fish-feed aquaculture industry. © 2020 The Author