Stress Distribution Analysis of the Rectangular and Star-Blade for Plastic Crusher Machine Using Finite Element Analysis

Recycling plastic waste can help reduce plastic waste, which is the world’s largest problem. The first solution is a plastic crusher machine, which converts plastic packaging into pellets, especially for plastics made from polyester, which is often used in bottle packaging. An integral part of the crushing machine is the crushing blade, which determines the design and analysis of the blade. The finite element analysis method is widely used in engineering analysis. Its results can provide useful information for the analysis of manufacturing processes. A rectangular blade and a star-shaped blade are the two types to consider. The analytical results obtained on the blade of the crusher machine in the rectangular shape that was given loads by 200 N, 400 N, and 600 N are 1.285 × 103 N/m2, 2.570 × 103 N/m2, and 3.855 × 103 N/m2, respectively. We obtained the displacements are 1.080 × 10-6 mm, 2.160 × 10-6 mm, and 3.241 × 10-6 mm, respectively. The maximum von mises stress result on consecutive star-shaped blades are 8.890 × 102 N/m2, 1.778 × 103 N/m2, and 2.667 × 103 N/m2. The displacement obtained are 1.211 × 10-6 mm, 2.422 × 10-6 mm, and 3.633 × 10-6 mm. The results of this analysis indicate that for the star blade, the shape is better than for the rectangular blade at the same time, and for the star blade, the stress is smaller than for the rectangular blade. Based on this simulation, the safety factor is 15, which means that it is more than 1, which means that it is safe.

Neighborhood Park Visit Impacted Psychological Health in Reducing Stress

This study examines the relationship between residents' stress levels with their participation at the neighborhood park in Petaling Jaya. The information on stress level and neighborhood park usage pattern proceed by distributing a questionnaire survey set. The outcome of this study identifies the connection of stress result with the usage pattern at the neighborhood park. Future research is recommended to have more than one case study with different demographic pattern backgrounds to enhance the residents' mental wellbeing by better planning neighborhood parks as a stress reliever. Keywords: Neighbourhood park; stress; preliminary study eISSN 2514-7528 © 2021 The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians / Africans / Arabians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia. DOI: https://doi.org/10.21834/jabs.v6i18.383

Effect of Rail Vehicle–Track Coupled Dynamics on Fatigue Failure of Coil Spring in a Suspension System

In a rail vehicle, fatigue fracture causes a significant number of failures in the coil spring of the suspension system. In this work, the origin of these failures is examined by studying the rail wheel–track interaction, the modal analysis of the coil springs and the stresses induced during operation. The spring is tested experimentally, and a mathematical model is developed to show its force vs. displacement characteristics. A vertical 10-degree-of-freedom (DOF) mathematical model of a full-scale railway vehicle is developed, showing the motions of the car body, bogies and wheelsets, which are then combined with a track. The springs show internal resonances at nearly 50–60 Hz, where significant stresses are induced in them. From the stress result, the weakest position in the innerspring is identified and a few guidelines are proposed for the reduction of vibration and stress in rail vehicles.

Promising Anti-Mitochondrial Agents for Overcoming Acquired Drug Resistance in Multiple Myeloma

Multiple myeloma (MM) remains an incurable tumor due to the high rate of relapse that still occurs. Acquired drug resistance represents the most challenging obstacle to the extension of survival and several studies have been conducted to understand the mechanisms of this phenomenon. Mitochondrial pathways have been extensively investigated, demonstrating that cancer cells become resistant to drugs by reprogramming their metabolic assessment. MM cells acquire resistance to proteasome inhibitors (PIs), activating protection programs, such as a reduction in oxidative stress, down-regulating pro-apoptotic, and up-regulating anti-apoptotic signals. Knowledge of the mechanisms through which tumor cells escape control of the immune system and acquire resistance to drugs has led to the creation of new compounds that can restore the response by leading to cell death. In this scenario, based on all literature data available, our review represents the first collection of anti-mitochondrial compounds able to overcome drug resistance in MM. Caspase-independent mechanisms, mainly based on increased oxidative stress, result from 2-methoxyestradiol, Artesunate, ascorbic acid, Dihydroartemisinin, Evodiamine, b-AP15, VLX1570, Erw-ASNase, and TAK-242. Other agents restore PIs’ efficacy through caspase-dependent tools, such as CDDO-Im, NOXA-inhibitors, FTY720, GCS-100, LBH589, a derivative of ellipticine, AT-101, KD5170, SMAC-mimetics, glutaminase-1 (GLS1)-inhibitors, and thenoyltrifluoroacetone. Each of these substances improved the efficacy rates when employed in combination with the most frequently used antimyeloma drugs.

Effect of Nigella Sativa on Oxidative Stress in Post-Menopausal Females

Background: The permanent cessation of menstrual periods in menopause causes a decline in estrogen levels and increased oxidative stress. Both of these factors lead to menopausal symptoms, cardiovascular diseases and osteoporosis in the postmenopausal females that negatively affect the quality of their lives. Antioxidant properties of Nigella sativa are due to its natural ingredient “thymoquinone” and have been studied in various animal and human studies. This study was done to determine beneficial effect of nigella sativa. Material and Methods: Thirty postmenopausal females were recruited in the study after taking consent. Nigella sativa was administered at a dose of 1g/day for 2 months after breakfast. Blood sample was taken for pre and post treatment glutathione (GSH) estimation. The SPSS version 21 was used to analyze the data. Paired t- test was applied. P value of< 0.05 was considered significant.Results: Regarding the effect of the Nigella sativa on oxidative stress, result indicated a highly significant increase from baseline (p<0.0001) after 8 weeks’ consumption of Nigella sativa. The effect size was calculated both for biochemical parameter GSH and general parameter like weight and BMI. The result of the effect size calculation showed larger effect size for GSH levels (3.9) and moderate sized effect for weight and BMI.Conclusion: Nigella Sativa showed beneficial antioxidant effects in post-menopausal females and might be responsible for a better quality of life in these women.

Investigating Permeability of Coal Samples of Various Porosities under Stress Conditions

Among the numerous factors that have an impact on coal permeability, coal porosity is one of the main parameters. A change in the mechanical stress applied to coal results in a change of porosity. The main objective of the conducted research was to answer the following question: is a decline in coal permeability a direct effect of a decrease in coal porosity, and does mechanical stress result solely in a porosity change? A study of coal porosity under mechanical stress conditions was conducted using a uniquely constructed measurement stand. The coal samples used were briquettes prepared from a granular coal material (middle-rank coal of type B—meta bituminous, upper carboniferous formation) from the “Zofiówka” coal mine, in Poland. In order to describe coal permeability, the Klinkenberg equation was used, as it takes into consideration the slippage effect, typical of porous media characterized by low permeability. On the basis of the obtained results, it was established that the values of the Klinkenberg permeability coefficient decrease as the mechanical stress and the corresponding reduction in porosity become greater. As the briquette porosity increased, the Klinkenberg slippage effect: (i) disappeared in the case of nitrogen, (ii) and was minor for methane. The briquettes used were characterized by various porosities and showed that mechanical stress results mainly in a change in coal porosity, which, in turn, reduces coal permeability.

Drought Stress Affecting Growth and Some Physiological Characters of Three Cocoa Clones at Seedling Phase

Drought stress can have substantial negative impacts on cocoa plant growth until affect the death of plant. The present study aimed to determine theeffect of drought stress on the some physiological characters of cacao (Theobroma cacao L.) seedlings. The research was carried out at the Indonesian Coffee and Cocoa Research Institute, Jember, East Java, Indonesia. This research was conducted from January–December 2017. The experiment was designed by using completely randomized block design with two factors and with three replications. The first factor was clones, namely ICS 60, Sulawesi 1 and KW 641 clones. The second factor was interval of watering treatment, namely watering every 2 days (control/adequate water condition), watering every 5 days (moderate stress), and watering every 8 days (severe stress). Result of this study concluded that drought stress reduced the growth of cocoa seedlings, mainly as a result of reducing photosynthetic activities in all stressed cocoa clone seedlings. Under drought stress, KW 641 and Sulawesi 1 had higher leaf area, chlorophyll a, chlorophyll b, total chlorophyll content, relative water content, and photosynthetic rate than ICS 60 clone.

Mutation rate variability as a driving force in adaptive evolution

Mutation rate is a key determinant of the pace as well as outcome of evolution, and variability in this rate has been shown in different scenarios to play a key role in evolutionary adaptation and resistance evolution under stress. Here we investigate the dynamics of resistance fixation in a bacterial population with variable mutation rates and show that evolutionary outcomes are most sensitive to mutation rate variations when the population is subject to environmental and demographic conditions that suppress the evolutionary advantage of high-fitness subpopulations. By directly mapping a molecular-level biophysical fitness function to the system-level dynamics of the population we show that both low and very high, but not intermediate, levels of stress result in a disproportionate effect of hypermutation on resistance fixation and that traditional definitions of the selection coefficient are insufficient to account for this effect. We demonstrate how this behavior is directly tied to the extent of genetic hitchhiking in the system, the propagation of high-mutation rate cells through association with high-fitness mutations. Our results indicate a substantial role for mutation rate flexibility in the evolution of antibiotic resistance under conditions that present a weak advantage over wildtype to resistant cells.