Behavior of fire exposed concrete-filled double skin steel tubular (CFDST) columns under concentric axial loads

This paper presents the result of an experimental investigation of axial behavior of concrete-filled double skin steel tubular (CFDST) columns exposed to high temperature under the action of monotonically applied concentric axial loads. The columns were exposed to ASTM E-119 standard fire curve until 600°C and kept constant for two different exposure time (i.e., 60 and 90 minutes). Failure patterns and reduction in strength, ductility and stiffness of CFDST columns are reported. Factors influencing the strength, ductility and stiffness of CFDST columns during fire exposure, i.e., exposure time, temperature of concrete core and temperature of inner steel tube, are also discusse

Numerical Study for MHD Stagnation-Point Flow of a Micropolar Nanofluid Towards a Stretching Sheet

In this paper, we investigated the magnetohydrodynamic (MHD) stagnation-point flow of micropolar nanofluid over a stretching sheet. A uniform magnetic field is applied normal to the flow. Nonlinear micropolar nanofluid problem in the presence of the strong concentration of microelements is modeled and then solved by numerical techniques. A parametric study of the involved parameters in the presence of spin gradient viscosity is conducted, and representative set of numerical results is illustrated in the graphical and tabular forms. The complete formulation of the Keller-box method for the considered flow problem is given, and a comparison of the obtained results is performed with the previous published results. The comparison shows that our present results have an excellent match with the previous results in a limiting case. We found that the non-dimensional temperature and its associated thermal boundary layer thickness are enhanced when we use the larger values of thermophoresis and Brownian motion parameter. The non-dimensional concentration is higher for larger thermophoresis parameter but smaller for higher Brownian motion parameter. It is also observed that the smaller values of Lewis number correspond to higher non-dimensional concentration and its associated boundary layer thickness

Ergonomic embedded in designing welding assembly tool for automotive manufacturing process

Ergonomics focuses on understanding how workers interact with their work environment, tools, and equipment. The proper ergonomics consideration in tool design will impact worker safety and productivity. Ergonomics-embedded knowledge is critical in designing welding assembly tools for automotive manufacturing. The study aims to improve the ergonomic issues faced by the automotive assembly welders. The methodology involves studying the existing welding assembly process in automotive manufacturing regarding RULA scores and simulating the postures using CATIA analysis. Based on the simulation, critical ergonomics issues should be identified and analyzed. Finally, the welding process is improved by designing the hand support for the workers to assemble parts. The results revealed that the RULA scores have improved from 7 (high risk at the existing condition) to 3 (medium risk) for both worker's hands after the support of the assembly tool. In conclusion, ergonomic embedding in welding assembly tool design has improved the automotive assembly worker's well-being. The findings of this study contribute to the growing body of knowledge on integrating ergonomics into automotive manufacturing processes, providing valuable insights for industry practitioners and researchers alike

Mechanical properties of concrete containing untreated palm oil fuel ash and egg shell powder

This study aims to use two (2) waste products, namely Palm Oil Fuel Ash (POFA) and Egg Shell Powder (ESP) as cement replacement in concrete. This is because the properties of POFA and ESP are similar to the properties of cement. The objective of this study is to determine the mechanical properties (compressive strength and tensile strength) of concrete containing POFA and ESP as cement replacement. With both properties known, the optimum percentage of POFA and ESP as cement replacement can then be determined. The percentage of replacement of POFA was fixed at 20%, however the percentages of ESP varied from 0 to 20%. Six 100 � 100 � 100 mm cubes and six 100 � 200 mm cylinders were prepared for each variation of percentages. The cubes and cylinders were tested for compressive and tensile strength after 7 and 28 days of water curing. Generally, as the percentages of ESP increased, the workability, compressive strength and tensile strength of the concrete sample decreased. In conclusion, the combination of POFA and ESP as cement replacement in concrete is only able to achieved 76% of targeted strength

Study of the Acute Stress Effects on Decision Making Using Electroencephalography and Functional Near-Infrared Spectroscopy: A Systematic Review

This systematic review provides a comprehensive analysis of studies that use electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) to investigate how acute stress affects decision-making processes. The primary goal of this systematic review was to examine the influence of acute stress on decision making in challenging or stressful situations. Furthermore, we aimed to identify the specific brain regions affected by acute stress and explore the feature extraction and classification methods employed to enhance the detection of decision making under pressure. Five academic databases were carefully searched and 27 papers that satisfied the inclusion criteria were found. Overall, the results indicate the potential utility of EEG and fNIRS as techniques for identifying acute stress during decision-making and for gaining knowledge about the brain mechanisms underlying stress reactions. However, the varied methods employed in these studies and the small sample sizes highlight the need for additional studies to develop more standardized approaches for acute stress effects in decision-making tasks. The implications of the findings for the development of stress induction and technology in the decision-making process are also explained

Chitin oligosaccharide N,N′-diacetylchitobiose (GlcNAc2) as antimicrobial coating against listeria monocytogenes on ready-to-eat shrimp

N,N′-diacetylchitobiose, also known as GlcNAc2, is a chitin oligosaccharide and is reported to possess antimicrobial activity against pathogenic bacteria. In this study, 1% (w/v) GlcNAc2 solution was applied on ready-to-eat (RTE) shrimp and evaluated as an antimicrobial coating against Listeria monocytogenes during storage at 4 °C for 16 days. Texture properties, colour, TBARS values, moisture content and bacterial counts were monitored and analysed every four days. The results indicated that the GlcNAc2 coating retarded the changes in texture properties, TBARS values and moisture content of the RTE shrimp during storage. The presence of GlcNAc2 showed no significant changes in RTE shrimp colour in contrast to the control. However, the growth of L. monocytogenes inoculated on the GlcNAc2-coated RTE shrimp was slower than that of the control sample with the highest log reduction of 0.5 log CFU/mL being observed. This study showed that the GlcNAc2 used as an antimicrobial coating was able to inhibit the growth of L. monocytogenes, while maintaining the quality of the RTE shrimp during refrigerated storage

Durability of coconut shell powder (CSP) concrete

The rising cost of construction in developing countries like Malaysia has led concrete experts to explore alternative materials such as coconut shells which are renewable and possess high potential to be used as construction material. Coconut shell powder in varying percentages of1%, 3% and 5% was used as filler material in concrete grade 30 and evaluated after a curing period of 7 days and 28days respectively. Compressive strength, water absorption and carbonation tests were conducted to evaluate the strength and durability of CSP concrete in comparison with normal concrete. The test results revealed that 1%, 3% and 5% of CSP concrete achieved a compressive strength of 47.65MPa, 45.6MPa and 40.55% respectively. The rate of water absorption of CSP concrete was recorded as 3.21%, 2.47%, and 2.73% for 1%, 3% and 5% of CSP concrete respectively. Although CSP contained a carbon composition of 47%, the carbonation test showed that CSP no signs of carbon were detected inside the concrete. To conclude, CSP offers great prospects as it demonstrated relatively high durability as a construction material

Crack classification in concrete beams using AE parameters

The acoustic emission (AE) technique is an effective tool for the evaluation of crack growth. The aim of this study is to evaluate crack classification in reinforced concrete beams using statistical analysis. AE has been applied for the early monitoring of reinforced concrete structures using AE parameters such as average frequency, rise time, amplitude counts and duration. This experimental study focuses on the utilisation of this method in evaluating reinforced concrete beams. Beam specimens measuring 150 mm x 250 mm x 1200 mm were tested using a three-point load flexural test using Universal Testing Machines (UTM) together with an AE monitoring system. The results indicated that RA value can be used to determine the relationship between tensile crack and shear movement in reinforced concrete beams

The antimetastatic and antiangiogenesis effects of kefir water on murine breast cancer cells

Background. Kefir is a unique cultured product that contains beneficial probiotics. Kefir culture from other parts of the world exhibits numerous beneficial qualities such as anti-inflammatory, immunomodulation, and anticancer effects. Nevertheless, kefir cultures from different parts of the world exert different effects because of variation in culture conditions and media. Breast cancer is the leading cancer in women, and metastasis is the major cause of death associated with breast cancer. The antimetastatic and antiangiogenic effects of kefir water made from kefir grains cultured in Malaysia were studied in 4T1 breast cancer cells. Methods. 4T1 cancer cells were treated with kefir water in vitro to assess its antimigration and anti-invasion effects. BALB/c mice were injected with 4T1 cancer cells and treated orally with kefir water for 28 days. Results. Kefir water was cytotoxic toward 4T1 cells at IC50 (half-maximal inhibitory concentration) of 12.5 and 8.33 mg/mL for 48 and 72 hours, respectively. A significant reduction in tumor size and weight (0.9132 ± 0.219 g) and a substantial increase in helper T cells (5-fold) and cytotoxic T cells (7-fold) were observed in the kefir water–treated group. Proinflammatory and proangiogenic markers were significantly reduced in the kefir water–treated group. Conclusions. Kefir water inhibited tumor proliferation in vitro and in vivo mainly through cancer cell apoptosis, immunomodulation by stimulating T helper cells and cytotoxic T cells, and anti-inflammatory, antimetastatic, and antiangiogenesis effects. This study brought out the potential of the probiotic beverage kefir water in cancer treatment

The effect of different feed formulation based on local feed resource on performance and stress parameter in breeder goat

Balanced nutrition is essential for health and performance of livestock. It is best when feed is formulated according to production stages of goat. However, as the goat grows, it may undergo transition of different feed formulation to meet its daily requirement. The transition may affect the performance of animals as well as it is a stressful condition. In this study, body weight gain and feed intake were used as indicators on performance, whereas hematological stress leucograms were used as indicator of stress parameter during implementation of different feed formulation among does. Eighteen adult does with similar body condition score and body weight approximately 20 kg were selected and divided into three groups equally (n = 6) and fed with different feed formulations, which were formulated using local feed source in the farm for a period of four weeks. Body weight was measured before implementation, on week 2 and week 4, blood sampling was conducted before implementation and during week 4 for comparison and feed intake was measured every day. All data were statistically analyzed using SPSS. Does fed with Diet 3 showed highest body weight gain and feed intake, followed by Diet 2 and Diet 1. There was significant difference (P0.05) as compared to normal value. Neutrophils:lymphocytes ratio for all groups were within normal range and no significant difference (P>0.05). The implementation of feed formulation according to production stages is recommended as it increases performance and prevents from nutritional stress