Vibration Energy Regeneration System Using Piezoelectric Sensor for Wideband Application

This paper presents a method for widening bandwidth by using non-uniform mass which use the concept of center of gravity. Piezoelectric acts as a tool to convert vibration energy to electrical energy. The displacement from the liquid movement plays a role to enhance the bandwidth as the beam bends. The bandwidth is widened 2 times higher compared without tip mass and 1.6 times increased than that of solid tip-mass. High viscosity and density will give a greater effect on the bandwidth at low volume compared to low properties of fluid. Rectangular container can resist the tension of liquid due to high viscosity and volume. The fluid-filled mass technique widened the bandwidth without reducing the harvested power

Fatigue life for type 316L stainless steel under cyclic loading

The paper presents the determination of fatigue life of 316L stainless steel at room temperature. Plenty of steel in the world has been investigated for a lot of application in the science and technology market. The mechanisms of fatigue of 316L stainless steels were studied and investigated. Fatigue tests of specimens were performed in accordance with ASTM E466-96. The fatigue tests were performed in constant load amplitude, constant frequency of 5 Hz with load ratio R=0.1. Fracture surface of specimens were examined by using Scanning Electron Microscope (SEM). The results showed that the endurance fatigue limit of 316L stainless steel was 146.45 MPa

Dihidroksistearinska kiselina (DHSA) visokog prinosa temeljena na kinetičkom modelu iz epoksidiranog palmina ulja

In recent years, studies related to the epoxidation of fatty acids have garnered much interest due to the rising demand for eco-friendly epoxides derived from vegetable oils. From the epoxidation reaction, there is a side reaction involving epoxide and water. This reaction produces a by-product – dihydroxystearic acid (C18H36O4, DHSA). DHSA is one of the chemical precursors in the production of cosmetic products. Therefore, a kinetic model was developed to determine the optimised epoxidation process and concentration of DHSA, where each of the reactions was identified. The kinetic rate, k parameters obtained were: k11 = 6.6442, k12 = 11.0185, k21 = 0.1026 for epoxidation palm oleic acid, and k41 = 0.0021, k51 = 0.0142 in degradation process. The minimum error of the simulation was 0.0937. In addition, DHSA yield optimisation was done through Taguchi method, and the optimum conditions obtained were H2O2/oleic acid – OA unsaturation molar ratio 1 : 1 (level 2), formic acid – FA/OA unsaturation molar ratio 0.5 : 1 (level 1), temperature 35 °C (level 1), and agitation speed 100 rpm (level 1). A high yield of DHSA can be achieved under these conditions. This work is licensed under a Creative Commons Attribution 4.0 International License.Posljednjih godina studije povezane s epoksidacijom masnih kiselina izazvale su veliko zanimanje zbog sve veće potražnje za ekološki prihvatljivim epoksidima dobivenim iz biljnih ulja. Iz reakcije epoksidacije dolazi do nuspojave koja uključuje epoksid i vodu. Tom reakcijom nastaje nusproizvod – dihidroksistearinska kiselina (C18H36O4, DHSA). DHSA jedan je od kemijskih prekursora u proizvodnji kozmetičkih proizvoda. Stoga je razvijen kinetički model za određivanje optimiranog procesa epoksidacije i koncentracije DHSA, gdje je identificirana svaka od reakcija. Dobiveni parametri kinetičke brzine, k bili su: k11 = 6,6442, k12 = 11,0185, k21 = 0,1026 za epoksidacijsku palmino-oleinsku kiselinu i k41 = 0,0021, k51 = 0,0142 u procesu razgradnje. Minimalna pogreška simulacije bila je 0,0937. Uz to, optimizacija prinosa DHSA provedena je Taguchijevom metodom, a dobiveni optimalni uvjeti su molarni omjer nezasićenja H2O2/oleinske kiseline – OA 1 : 1 (razina 2), molarni omjer nezasićenja mravlje kiseline – FA/OA 0,5 : 1 (razina 1), temperatura 35 °C (razina 1) i brzina miješanja 100 o min–1 (razina 1). Pod tim se uvjetima može postići visok prinos DHSA. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna

Systematic review and meta-analysis of prognostic models in Southeast Asian populations with acute myocardial infarction

BackgroundThe cultural and genetic diversity of the Southeast Asian population has contributed to distinct cardiovascular disease risks, incidence, and prognosis compared to the Western population, thereby raising concerns about the accuracy of predicted risks of existing prognostic models.ObjectivesWe aimed to evaluate the predictive performances of validated, recalibrated, and developed prognostic risk prediction tools used in the Southeast Asian population with acute myocardial infarction (AMI) events for secondary eventsMethodsWe searched MEDLINE and Cochrane Central databases until March 2022. We included prospective and retrospective cohort studies that exclusively evaluated populations in the Southeast Asian region with a confirmed diagnosis of an AMI event and evaluated for risk of secondary events such as mortality, recurrent AMI, and heart failure admission. The CHARMS and PRISMA checklists and PROBAST for risk of bias assessment were used in this review.ResultsWe included 7 studies with 11 external validations, 3 recalibrations, and 3 new models from 4 countries. Both short- and long-term outcomes were assessed. Overall, we observed that the external validation studies provided a good predictive accuracy of the models in the respective populations. The pooled estimate of the C-statistic in the Southeast Asian population for GRACE risk score is 0.83 (95%CI 0.72–0.90, n = 6 validations) and for the TIMI risk score is 0.80 (95%CI: 0.772–0.83, n = 5 validations). Recalibrated and new models demonstrated marginal improvements in discriminative values. However, the method of predictive accuracy measurement in most studies was insufficient thereby contributing to the mixed accuracy effect. The evidence synthesis was limited due to the relatively low quality and heterogeneity of the available studies.ConclusionBoth TIMI and GRACE risk scores demonstrated good predictive accuracies in the population. However, with the limited strength of evidence, these results should be interpreted with caution. Future higher-quality studies spanning various parts of the Asian region will help to understand the prognostic utility of these models better.Systematic review registrationhttps://www.crd.york.ac.uk/prospero/display_record.php?%20RecordID=228486

Water retention properties of a fused deposition modeling based 3D printed polylactic acid vessel

The applications of fused deposition modelling (FDM) based 3D printing have gone beyond merely simple prototypes to where functionalities are expected. One of such functionalities is the water retention properties, especially for fluid handling products, either completely waterproof or deliberately porous. Issues arise especially in determining crucial parameters and their optimization to achieve the desired water retention properties. This study established the relationship among printing parameters (layer thickness and wall thickness) and water temperature with leakage flow rate. A series of 3D printed polylactic acid (PLA) vessels were fabricated at various layer height and wall thickness. Then, the volumetric loss of water at various temperatures was measured, elapsed time was recorded, and the leakage flow rate was calculated for each 3D printed vessel. It has been found that the leakage flow rate decreased when layer height decreased, wall thickness increased, and water temperature decreased. Based on multilinear regression analysis, the magnitude of influence for the layer height was the highest, which could reach at a point where variation in wall thickness and water temperature had no effect. A regression model having 81.27% fitness that provided a quantitative relationship among all parameters had also been obtained. ANOVA analysis revealed that all parameters were statistically significant in optimizing as well as predicting the value of the leakage flow rate

Health-related quality of life among hepatitis c patients in Pahang State, Malaysia: a cross-sectional study

Measurement of health-related quality of life (HRQOL) among hepatitis C patients is crucial in assisting health care providers to understand the complex psychosocial impact of disease on patients, thus facilitating a more patient-centred care. There is still scarcity of data on this matter, not adequately explored and nor has it been empirically studied in Malaysia. Thus, this study aims to measure the HRQOL among hepatitis C patients attending a tertiary hospital in Pahang, Malaysia. This was a cross-sectional study conducted among 195 hepatitis C patients attending Hospital Tengku Ampuan Afzan (HTAA), the main public tertiary hospital in Pahang. HRQOL was assessed using the 36-item short-form survey (SF-36v2). Respondents had lower scores in physical (mean score = 48.88 ± 8.9) and mental (mean score = 47.70 ± 9.1) health components of HRQOL than normal population (mean score > 50). Those who completed treatment had higher scores in both physical and mental health component, compared to those who was not treated or on treatment. There was no significant association between HRQOL and gender, age, marital status, employment status and education level. Our findings showed that patients with hepatitis C, in general, have poor HRQOL in both physical and mental health components. Thus, this study highlights a pressing need for holistic disease management by taking into account patients’ quality of life as part of the inter-disciplinary approach

Preparation and characterization of calcium hydroxyphosphate (hydroxyapatite) from tilapia fish bones and scales via calcination method

Calcium hydroxyphosphate (hydroxyapatite) is a calcium phosphate that is widely used in biomedical application. Hydroxyapatite is an excellent component for bone substitutes for their chemical and structural similarity to natural bone component. In this research, hydroxyapatite was synthesized from tilapia fish bones and scales using calcination method with 3 different temperatures namely 1000 °C, 900 °C and 800 °C. The obtained hydroxyapatite powder was characterized using several techniques such as Fourier-Transform infrared spectroscopy Attenuated total reflection (FTIR-ATR), scanning electron microscope (SEM), proximate analysis and X-ray diffraction (XRD). The results indicated that temperature 1000 °C has the highest weight loss with 21.825 g compared to the temperature 800 °C and 900 °C. From FTIR-ATR analysis, the presence of characteristic peaks for hydroxyl group, phosphate groups and water molecule indicated that the powder were hydroxyapatite. SEM results showed that increasing temperature had led to more dense structure. The hydroxyapatite powder were further analysed for their proximate analysis. The results proved that the highest contents of ash, fat, moisture and crude protein were observed at 1000 °C as compared to 900 °C and 800 °C. Based on this study, it revealed that produced pure hydroxyapatite from natural resources could be a potential candidate for food industry as protein enhancer

Palm date meal as a non-traditional ingredient for feeding aquatic animals: A review

Protein ingredients in aquafeed are one of the most important factors responsible for the development and sustainability of aquaculture. Currently, because of high costs and fluctuating production, some animal and plant protein sources are unable to satiate the increasing demand from the fish feed manufacturers. Aquatic animals’ nutritional requirements have been accorded particular focus with less costly feedstuff in aqua feed given extra weightage. There has been increasing attention in recent years on finding methods to recycle the animal and plant by-products for feed preparation. Due to its vital amino acid content as well as high protein composition, palm date meal (PDM) which is a renewable and sustainable resource is expected to be a viable raw material option for replacing protein ingredients (e.g., fish meal and soybean meal) or as a supplement in fish feed. PDM is an agro-industry by-product which left from dates as waste in several countries. This article reviewed the current research including the source, derivatives, and the potential of PDM as a possible alternative to the conventional plant and animal protein sources. Also, the added value of using PDM waste in aquafeed to reduce the feed cost, enhance this e growth rate of fish, improve the health and well-being of fish, and subsequently sustain the aquaculture industry. Therefore, this review paper will illuminate the possibility of PDM as a promising feed source and also the present knowledge and future perspectives about the application of PDM in aquaculture