There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

https://cyberleninka.org/article/n/1301722.pdf

Effect of fibre orientations on the mechanical properties of kenaf–aramid hybrid composites for spall-liner application

The large use of nanomaterials in many fields of application and commercial products highlights their potential toxicity on living organisms and the environment, despite their physico-chemical properties. Among these, silver nanoparticles (Ag NPs) are involved in biomedical applications such as antibacterial agents, drug delivery vectors and theranostics agents. In this review, we explain the common synthesis routes of Ag NPs using physical, chemical, and biological methods, following their toxicity mechanism in cells. In particular, we analyzed the physiological cellular pathway perturbations in terms of oxidative stress induction, mitochondrial membrane potential alteration, cell death, apoptosis, DNA damage and cytokines secretion after Ag NPs exposure. In addition, their potential anti-cancer activity and theranostic applications are discussed.

https://www.mdpi.com/2079-4991/8/5/319/pdf

Silver Nanoparticles: Synthetic Routes, In Vitro Toxicity and Theranostic Applications for Cancer Disease

Hybrid reinforced thermoset polymer composite in energy absorption tube application: a review

Hybrid composites offer a combination of advantages of constituent components to produce a material with determined properties. In the present work, woven hybrid composite was prepared by hand lay-...

/pdf/mechanical-performance-of-woven-kenaf-kevlar-hybrid-2ldyxd3xr3.pdf

Mechanical performance of woven kenaf-Kevlar hybrid composites

Uniform, well-dispersed, silver nanoparticles (AgNPs) were prepared by a simple chemical reduction method. The particles were synthesized via the reduction of AgNO3 by trisodium citrate and ascorbic acid as a surfactant. The resulting AgNPs were characterized by X-ray diffraction analysis, transmission electron microscopy, and scanning electron microscopy. It was found that the size of the AgNPs ranged from 35– 80 nm, with an average of 50 nm. In this study, the effects of trisodium citrate and ascorbic acid, which act as reducing agent and surfactant respectively on the morphology of the silver nanoparticles, were investigated. It was found that the increasing concentration of trisodium citrate resulted in decreasing size of silver nanoparticles, while increasing the concentration of ascorbic acid shows the opposite effect. Moreover, the quasi-spherical shape of as-synthesized silver nanoparticles is also more uniform with the increase of trisodium citrate. Meanwhile, a slight change in particle shape from quasi-spherical to polygonal was observed as the concentrations of ascorbic acid were increased.  Keywords: Chemical synthesis; silver nanoparticles; reducing agent; surfactant.

/pdf/synthesis-of-silver-nanoparticles-by-chemical-reduction-2748qcncqy.pdf

Synthesis of Silver Nanoparticles By Chemical Reduction Method: Effect of Reducing Agent and Surfactant Concentration

Body armor is a material to protect body from injury of various kind of high speed projectile impact velocity in combat or other dangerous situation. Researchers were found to actively research and exploring new body armor technology due to the invention of new firearms. Furthermore, they were also competing in developing ballistic panel which is lighter in weight, more flexible and comfort in use, cheaper in cost and manufacturability. This paper reviews the body armor commercial and current development materials, structure and construction techniques involved and related works on enhancing ballistic energy absorption.

Body Armor Technology: A Review of Materials, Construction Techniques and Enhancement of Ballistic Energy Absorption

Natural fibre has become the subject of interest for research and development by various organizations due to its biodegradable and competitive mechanical properties. However most of the researchers are focusing on random orientation and compressed mat with only little researches concerned with woven or textile structure. This research work involved with mechanical analysis of woven natural fibres composite specifically coir and kenaf natural fibres. Plain woven coir and kenaf were produced from their yarns using self designed weaving device. The woven fibres were then converted as reinforcement in composite. Woven composite was prepared using manual hand lay up technique couple with vacuum bagging. Impact penetration and flexural (three point bending) test were conducted on composite sample. Morphological analysis was performed using Scanning Electron Microscope (SEM). From the results obtained, dry woven coir composite displayed better mechanical properties for both impact and flexural properties compared to kenaf composite. Warp direction of coir composite and kenaf composite showed a better flexural strength compared to weft composite direction. Coir yarn with slight lower fineness value than kenaf yarn had contributed to the higher fibre density in woven structure. The structure used as composite reinforcement in turn produced better mechanical properties.

Impact and Flexural Properties of Imbalance Plain Woven Coir and Kenaf Composite

Study on degradation behaviors of biodegradable poly(butylene adipate-co-terephthalate) (PBAT) blended with different compositions of thermoplastic starch (TPS) under soil burial and natural weathering environments is vital in order to predict the product service-life and planning for in situ biodegradation after product disposal. In this article, different compositions of TPS (0%, 20%, 40%, 50%, and 60%) were compounded with PBAT using single screw extruder. The samples were characterized for their tensile properties, fractured surface morphology, water barrier and surface hydrophorbicity properties in order to investigate the effect of starch fractions in PBAT blends. The degradation behavior under natural weathering and soil burial conditions was also determined during the 9 months duration by observing the change of physical appearance, weight loss, surface morphology, chemical structural, and tensile properties. The findings showed that the addition of TPS (20%, 40%, 50%, and 60%) had led to a reduction in tensile strength (41.47%, 60.53%, 63.43%, and 68.53%), and reduction in elongation at break (42.92%, 92.1%, 92.23%, and 93.22%, respectively) and water barrier properties. The findings also showed that there were distinct degradation behavior under both conditions. Upon exposure to natural weathering, photodegradation and Norrish type I & II occurred whereas under the soil burial condition, hydrolytic, and enzymatic degradation take places. Sample with the highest starch contents underwent the highest weight loss and reduction in tensile properties under both environments. The findings in this study are useful in order to investigate the feasibility of PBAT/Tapioca starch blends for biodegradable plastic film for various industrial applications especially in packaging and agricultural mulch. 

Effect of different starch contents on physical, morphological, mechanical, barrier, and biodegradation properties of tapioca starch and poly(butylene adipate‐co‐terephthalate) blend film

The tensile properties of untreated and alkali treated betel nut husk fiber were investigated using single fiber tensile test method and the fiber structures were observed using SEM technique. The alkali treatment aids in the removal of lignin, hemicellullose and non-cellulosic components such as wax and pectin on the betel nut husk fiber surface, which yields bigger lumen size and rougher betel nut husk fiber surface. The alkali treatment enhanced the elongation at break of betel nut husk fiber but at the expense of tensile strength and Young's modulus.

Jaafar Mariatti

Papers

Synthesis of Silver Nanoparticles By Chemical Reduction Method: Effect of Reducing Agent and Surfactant Concentration

Body Armor Technology: A Review of Materials, Construction Techniques and Enhancement of Ballistic Energy Absorption

Impact and Flexural Properties of Imbalance Plain Woven Coir and Kenaf Composite

Effect of different starch contents on physical, morphological, mechanical, barrier, and biodegradation properties of tapioca starch and poly(butylene adipate‐co‐terephthalate) blend film

Effect of Alkali Treatment on the Tensile Behavior and Structure of Betel Nut (Areca catechu) Husk Fiber