Impact damage resistance and post impact tolerance of optimum banana-pseudo stem fiber reinforced epoxy sandwich structures

Banana fiber has a high potential for use in fiber composite structures due to its promise as a polymer reinforcement. However, it has poor bonding characteristics with the matrixes due to hydrophobic-hydrophilic incompatibility, inconsistency in blending weight ratio, and fiber length instability. In this study, the optimal conditions for a banana/epoxy composite as determined previously were used to fabricate a sandwich structure where carbon/Kevlar twill plies acted as the skins. The structure was evaluated based on two experimental tests: low-velocity impact and compression after impact (CAI) tests. Here, the synthetic fiber including Kevlar, carbon, and glass sandwich structures were also tested for comparison purposes. In general, the results showed a low peak load and larger damage area in the optimal banana/epoxy structures. The impact damage area, as characterized by the dye penetration, increased with increasing impact energy. The optimal banana composite and synthetic fiber systems were proven to offer a similar residual strength and normalized strength when higher impact energies were applied. Delamination and fracture behavior were dominant in the optimal banana structures subjected to CAI testing. Finally, optimization of the compounding parameters of the optimal banana fibers improved the impact and CAI properties of the structure, making them comparable to those of synthetic sandwich composites

Recent progress of rice husk reinforced polymer composites: a review

Recently, because of the rising population, carbon overloading, and environmental distress, human beings have needed to increase awareness and responsibility for the reduction of agricultural waste. The utilization of agricultural waste as a filler material in reinforced polymers is a fascinating discovery. This review paper attempts to study the physical, mechanical, and thermal behavior of rice husk (RH) as a fiber for reinforcing various synthetic polymers, based on recent studies, conducted between 2017 and 2021. It also highlights that advanced modification techniques could further improve the performance of composites by tailoring the physical and chemical substances of the fiber or matrix. The thermal properties, including flame-retardance and thermal behavior, are also discussed. The characteristics of the fiber-matrix interaction between RH and the polymer matrix provide essential insights into the future-ready applications of this agricultural waste fiber. The way forward in researching RH polymer composites is finally reviewed

Screening and evaluation of local bacteria isolated from shellfish as potential probiotics against pathogenic Vibrios

The present study was carried out to isolate, screen and evaluate potential candidates of local bacteria isolated from tiger shrimp Penaeus monodon and slipper cupped oysters Crassostrea iredalei as probiotics in shellfish aquaculture. A total of 144 of bacteria were successfully isolated from the intestine and stomach of 20 tails of healthy adult tiger shrimp P. monodon, while 136 were successfully isolated from the digestive tract, gills and inner shells of 10 healthy adult C. iredalei. The number of potential isolates was narrowed down to two from tiger shrimp, and one from slipper cupped oyster after in vitro screening assays. The three isolates, labeled as G11, I24 and S66, were identified as Virgibacillus sp., Bacillus sp. and Exiquobacterium sp., respectively, using 16S rDNA gene analysis. The antagonistic ability of the isolates towards Vibrio alginolyticus and Vibrio harveyi were conducted in stagnant and liquid modes via spot lawn and broth co-culture assay, respectively. In these assays, all the potential probionts were inhibitory to both pathogenic vibrios. In the in-vivo assay, Artemia was used as host and treated with different concentrations of potential probionts (10⁴, 10⁶ and 10⁸ CFU ml⁻¹), and challenged with V. alginolyticus ana V. harveyiat 10⁵ CFU ml⁻¹ Respectively, Artemia treated with probiont Gl 1 at all concentrations and challenged with V. alginolyticus had increased survival (70-80 %), which was significantly higher as compared with group with only the pathogen (20 %). Meanwhile, probiont I24 increased the survival of Artemia by 70 % at a concentration of 10⁸ CFU ml⁻¹ after being challenged with V. alginolyticus and Artemia treated with 10⁶ CFU ml⁻¹ of probiont S66 had increased survival of 90% after being challenged with V. harveyi. Thus, the three isolates might have potential applications as probiotics in shellfish aquaculture against vibriosis

DNA vaccination for prostate cancer: key concepts and considerations

While locally confined prostate cancer is associated with a low five year mortality rate, advanced or metastatic disease remains a major challenge for healthcare professionals to treat and is usually terminal. As such, there is a need for the development of new, efficacious therapies for prostate cancer. Immunotherapy represents a promising approach where the host’s immune system is harnessed to mount an anti-tumour effect, and the licensing of the first prostate cancer specific immunotherapy in 2010 has opened the door for other immunotherapies to gain regulatory approval. Among these strategies DNA vaccines are an attractive option in terms of their ability to elicit a highly specific, potent and wide-sweeping immune response. Several DNA vaccines have been tested for prostate cancer and while they have demonstrated a good safety profile they have faced problems with low efficacy and immunogenicity compared to other immunotherapeutic approaches. This review focuses on the positive aspects of DNA vaccines for prostate cancer that have been assessed in preclinical and clinical trials thus far and examines the key considerations that must be employed to improve the efficacy and immunogenicity of these vaccines

The pumping parameters for Er-doped tellurite glass

Erbium doped tellurite glass rod of the 78.5 TeO2 - 20 ZnO - 1.5 Er2O3 where has successfully been fabricated as lasing medium and have been investigated by means of their properties needed in lasing application. The external triggering method is used to generate high peak current in several microsecond pulse duration. The external triggering circuit design consists of power supply, discharge capacitor, control unit, pulse forming network and ignition circuit. This driver operates in single mode pulse that can be adjusted corresponding to the controller which can vary from 650V to 1000V. The operation is started initially with an external trigger pulse which is the voltage pulse of 8kV with pulse duration 20.0μs. The connection operated by trigger thrystor (SCR) as a switch and ionized gaseous inside the lamp. After the gaseous breakdown, the current from the capacitor flows continuously through the flashlamp. The output current is initially increased proportion in order to the input energy. Maximum value of peak current flashing at 888A with higher input energy, while, the increasing voltage is not linearly increased with the input energy. From the plotted graph of current and voltage, V-I, shows a nonlinear relationship with the electrical input energy. The developed flashlamp driver has produced about 87% in efficiency while another 13% is lost in the circuit resistance. Flashlamp radiation is detected by using spectrometer in the range of 200nm to 1000nm. The beam is used to excite the erbium glass medium and a coherent beam of 1550nm wavelength is produced

Estimating the apartment foreclosure discount in Kuala Lumpur

This paper examines the price differential between properties traded in the auction market and private negotiated market.With the exception of anecdotal information which suggests that auctioned or foreclosed properties in Malaysia tend to be sold at a deep discount, no study has thus far attempted to quantify this foreclosure discount.We uncover this question by examining listing price of apartment properties in Kuala Lumpur during 2009-2014.For each of the auctioned apartment in our sample, we match it with comparable non-auctioned apartment located in the same building block.This matching strategy essential net out the locational and neighbourhood characteristics of the properties, thus, allowing us to attribute the price differential to the “stigma effect” associated with auctioned or foreclosed properties.We document that auctioned apartments are listed at a discount of 34% as compared to apartments listed in the private negotiated market

Mode i fracture toughness of optimized alkali-treated bambusa vulgaris bamboo by box-behnken design

Alkaline treatment is widely being used to treat natural fibres and it improves the fibre surface for better bonding with the polymer matrix. The aim of this study is to optimize the alkaline treatment variables such as sodium hydroxide (NaOH) concentration, soaking and drying time that influence the strength of natural fibres, including bamboo. In this study, Box-Behnken design (BBD) of the response surface method was employed to set an experimental parameter of alkaline treatment for the bamboo specimen. In order to investigate the effect of treatment conditions on crack propagation behaviour of the bamboo along the longitudinal direction, Mode I interlaminar fracture toughness (GIC) test was carried out. It can be suggested from the statistical analysis approach (ANOVA) that bamboo treated with 1 wt% concentration of NaOH is able to reach fracture toughness value up to 365.86 J/m2, which differs by only 0.82% from the experimental finding. It is also shown that all proposed variables for treatment in this study i.e. the concentration of the NaOH is highly significant with the soaking and drying time

The Learning Process in Cultural of Fourth Industrial Revolution 4.0 (4IR)*

This study is focus to emergence of a new technology known as ‘The Fourth Industrial Revolution' or the Industrial Revolution 4.0 has led to the current development of technology that predicts 50 billion electronic devices will interact with each other. Meeting the challenges of the Industrial Revolution 4.0, all students at the Institute of Higher Education (IPT) need to be prepared with this new era. Accordingly, a study was conducted on 30 students of the Faculty of Information Science and Technology (FTSM) Universiti Kebangsaan Malaysia (UKM) in Bangi, Selangor. This study aims to identify the level of knowledge, willingness and skills among students to pursue the Challenge of Industrial Revolution 4.0. This research is a descriptive study which use Likert scale. The data was analyzed using SPSS software. The findings show that the students' knowledge level towards the Industrial Revolution 4.0 is at a moderate level. Meanwhile, the study also found that student readiness was at moderate level. The findings also found that the skills level towards the Industrial Revolution 4.0 is at a moderate level. Researchers suggest that students should focus on maintaining the identity, sustainability of the mind, culture and the identity of students in the face of the new National Development and Transformation Plan 2050. Students need to get out of the habit and master the 4C elements of Critical Thinking & Problem Solving, Communication, Collaboration and Creativity