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Arthropod-borne viruses have become a major threat to human health worldwide. The implementation of personal protection through clothing is necessary to avoid insect bites, especially for military operations and public health emergencies. Development of synthetic repellents in clothing impregnation has been well-established whilst, numerous studies regarding the application of essential oils on textile substrates have been carried out to develop their use as an alternative to synthetic repellents. The present review attempts to give a general overview and summarize the current technology used in treated clothing, as well as the advantages, challenges, limitations, and factors that may affect the performance of synthetic repellents and essential oils in textiles. Current research trends in developing more effective repellents from essential oils are also summarized.

In the present study, stereoregular poly(3-hexylthiophene-2,5-diyl) (P3HT) coated hydroxylated multi-walled carbon nanotubes (MWCNT-OH) nanocomposites were prepared over different reaction times of non-covalent functionalization. The reaction time was set as 24, 48, 72, 96, and 120 hours. The structure and optical characteristics of nanocomposites were analyzed using Fourier-transform infrared (FTIR) and ultraviolet-visible (UV-Vis) spectroscopy, respectively. Reaction time affected prepared nanocomposites by decreasing the intensity of the P3HT/MWCNT-OH peaks gradually with increasing of the reaction time. Comparing with the pure P3HT and MWCNT-OH, the calculated energy band gap and the Urbach energy of the nanocomposites were reduced proportionally as the reaction time reached 120 hours and achieved 2.60 and 0.329 eV, respectively.

This paper presents a structural analysis of various methods to produce bacterial cellulose (BC) from Nata de Coco (Acetobacter xyllinum). BC sheet, BC chem and BC mech powder were successfully prepared using oven drying, chemical and mechanical treatment. The X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and field emission scanning electron microscopy (FESEM) were used to analyze the structure of prepared BC. The structure of bacterial cellulose was compared with the structure of commercial microcrystalline cellulose (MCC) and cotton fabric. The XRD results showed that the BC sheet sample had the highest degree of crystallinity (81.76%) compared to cotton cellulose (75.73%). The crystallite size of cotton was larger than the BC sheet, with the value of 6.83 ηm and 4.55 ηm, respectively. The peaks in the FTIR spectra of all BC were comparable to the commercial MCC and cotton fabrics. FESEM images showed that the prepared BC sheet, BC mech, and BC chem had an almost similar structure like commercial MCC and cotton fabric. It was concluded that simple preparation of BC could be implemented and used for further BC preparation as reinforcement in polymer composites, especially in food packaging.

Purpose In this work, the blends of poly(methyl methacrylate), PMMA and poly(methyl vinyl ether-alt-maleic acid monoethyl ester), PMVEMA-ES are studied as organic coatings to evaluate the impact of intermolecular hydrogen bonding on the physical and thermal characteristics of the prepared coatings. Design/methodology/approach PMMA (Mw = 120,000 g mol-1) was chosen as our binder material. Due to the low adhesion property of PMMA on polar substrates, it was blended with PMVEMA-ES, which contains polar –COOH groups, to improve the adhesion and thermal properties of the coatings by forming intermolecular hydrogen bonds. A cross-hatch adhesion test was carried out to evaluate the adhesion strength of different ratios of PMMA/PMVEMA-ES blends as coatings. In addition, changes in the glass-transition temperature, Tg as the composition varies were studied using Differential Scanning Calorimetry, DSC. Then, glossiness and hiding power tests were also conducted to evaluate the physical properties of the prepared coatings. Findings Upon a closer look at the DSC results, it was found that blends consisting of 12.5, 25.0 and 87.5 wt. % PMMA were completely compatible due to the presence of only a single Tg in their thermograms. Other blend compositions showed two distinct Tgs, indicating partial compatibility. Furthermore, the addition of PMVEMA-ES caused the Tg of PMMA to shift to lower temperatures, a strong indication of intermolecular hydrogen bonding interactions between the two components. From the cross-hatch adhesion results, the addition of PMVEMA-ES improved the adhesion properties of PMMA coating, except for blends consisting of 62.5 and 75.0 wt. % PMMA possibly due to the partial incompatibility between the two components. These findings were further corroborated with the results of glossiness and hiding power measurements. The superior result was seen for the blend consisting of 12.5 wt. % PMMA with strong adhesion property, high glossiness, compatibility and high translucency. Practical implications PMVEMA-ES can potentially be used as an adhesion promoter in PMMA-based coating formulations. Originality/value This is the first report on the properties of PMMA/PMVEMA-ES blends as coatings.

Novel electronic nanomaterial, the carbon nanotube (CNT) has emerged in many sensor applications as such its state dispersion has considerable importance to ensure the sustainability of its electronic properties. In this paper, we reported a state of art conductivity mapping on nanostructure surface of single walled carbon nanotubes (SWCNT) and poly(3-hexylthiophene-2,5-diyl), (P3HT) as potential sensing film. This composite is proposed to give selective analyte anchoring across the film as well as improved carrier mobility. The easy solution processing method was chosen to produce non-covalently wrapped conducting polymer onto the surface of SWCNT. We successfully observed high resolution images of the SWCNT walls that indicated increase of the thickness due to polymer wrapping. The image obtained from conductivity atomic force microscopy (CAFM) show the film’s electrical distribution that correlated with the observed nanostructure of film. Supporting optical characteristics of the nanocomposite obtained from UV-Vis spectroscopy and Raman spectroscopy discussed the morphology of the polymer wrapping and the state of dispersion of the polymer and the nanotubes. It is hypothesized the filament structures made by P3HT/SWCNT can give better sensing performance due to modification of π-π electronic band of SWCNT.

In this paper, trap levels around the glass transition temperature (Tg) of polymers have been characterized using Thermally Stimulated Current (TSC) technique. Deconvolution on α-peaks of the Tg for PE (-104 °C), plasticized PVC (-35 °C), PMMA (90 °C) and PET (96 °C) were carried out based on the first-order kinetic theory for non-Debye relaxation. Using temperature, T from TSC experimental data, we have successfully separated the α-peaks of the thermoplastic polymers. It is found that the complex curve of α-peaks can composed of four (4) to eight (8) sub peaks. Dominant sub peaks were identified at Tmax = -105 °C, -34 °C, 89 °C and 92 °C for PE, pPVC, PMMA and PET, respectively. These peaks show activation energy, Ea of shallow and deep trap centers ranged from 0.3 eV to 4.6 Ev where they represent the depolarization of localized dipoles and space charges relaxations in the polymers.

Graphene is a single-atom-thick sheet of sp2 hybridized carbon atoms that are packed in a hexagonal honeycomb crystalline structure. This promising structure has endowed graphene with advantages in electrical, thermal, and mechanical properties such as room-temperature quantum Hall effect, long-range ballistic transport with around 10 times higher electron mobility than in Si and thermal conductivity in the order of 5,000 W/mK, and high electron mobility at room temperature (250,000 cm2/V s). Another promising characteristic of graphene is large surface area (2,630 m2/g) which has emerged so far with its utilization as novel electronic devices especially for ultrasensitive chemical sensor and reinforcement for the structural component applications. The application of graphene is challenged by concerns of synthesis techniques, and the modifications involved to improve the usability of graphene have attracted extensive attention. Therefore, in this review, the research progress conducted in the previous decades with graphene and its derivatives for chemical detection and the novelty in performance enhancement of the chemical sensor towards the specific gases and their mechanism have been reviewed. The challenges faced by the current graphene-based sensors along with some of the probable solutions and their future improvements are also being included.

Inspired by nature, cellulose extracted from plant wastes has been explored, due to its great potential as an alternative for synthetic fiber and filler that contributes to structural performance. The drive of this study was to extract, treat, and evaluate the characteristics of rice straw (RS) (Oryza sativa L.) cellulose as a biodegradable reinforcement to be utilized in polymer base materials. Two routes of extraction and treatment were performed via the pulping (Route 1) and chemo-mechanical methods (Route 2), in order to discover comparative characteristics of the synthesized cellulose fiber. Comprehensive characterization of RS cellulose was carried out to determine crystallinity, surface morphology, and chemical bonding properties, using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Fourier transform infra-red (FTIR), respectively. The XRD test results showed that the crystallinity index (CI) of cellulose powder (CP) decreased after the surface modification treatment, Route 2, from 64.50 to 50.10% CI for modified cellulose powder (MCP), due to the surface alteration of cellulose structure. From Route 1, the crystallinity of the fibers decreased up to 33.5% (dissolve cellulose, DC) after the pulp went through the surface modification and dissolution processes, resulting from the transformation of cellulose phase into para-crystalline structure. FESEM micrographs displayed a significant reduction of raw RS diameter from 7.78 µm to 3.34 µm (treated by Route 1) and 1.06 µm (treated by Route 2). The extracted and treated cellulose via both routes, which was considerably dominated by cellulose II because of the high percentage of alkaline used, include the dissolve cellulose (DC). The dissolution process, using NMMO solvent, was performed on the pulp fiber produced by Route 1. The fiber change from cellulose I to cellulose II after undergoes the process. Thus, the dissolution process maintains cellulose II but turned the pulp to the cellulose solution. The acquired characteristics of cellulose from RS waste, extracted by the employed methods, have a considerably greater potential for further application in numerous industries. It was concluded that the great achievement of extracted RS is obtained the nanosized fibers after surface modification treatment, which is very useful for filler in structural composite applications.

PurposeThis paper aims to discuss the use of the sensor material in coating to detect defects which can cause corrosion on metal substrate. This coating consists of sodium polyacrylate (SP) to detect the presence of water and fluorescence substance 2-[4-(piperidin-1-yl)-5H-chromeno-[2,3-d]pyrimidin-2-yl]phenol [benzopyranopyrimidine (BPP)] to detect crack formation.Design/methodology/approachThe coating resin is a mixture of poly(methyl methacrylate) (PMMA) and poly (methyl vinyl ether-alt-maleic anhydride). The additives are used to provide a visual indicator to the observer for when the coating exhibits any defects, so that quick action can be taken before corrosion develops further. SP has absorbent properties and expand when in contact with water, while BPP exhibits high luminous intensity in its solid form that is easily perceivable when exposed to UV. PVM/MA was used as the binder with ethanol as the solvent. The resistance of this coating towards water penetration was investigated using electrochemical impedance spectroscopy (EIS). The coating’s performance was observed in terms of visible optical appearance.FindingsThe sensor coating developed in this project serves as visual aid to the observer through the expansion of SP and high fluorescence of BPP material after the top coat is physically damaged. These findings are in provision of preventive measures that can be taken in case of top coat failure.Research limitations/implicationsThe resistance of the coating that contained SP could not be investigated with EIS due to its ability to expand immediately when in contact with liquids.Practical implicationsThe coating developed in this study may be to detect corrosion.Originality/valueThe sensor material used has not been previously studied in applications to detect the presence of water or used to detect crack formation.

This study is an attempt to develop an index on ethnic tolerance among the Malay, Chinese and Indian undergraduate students of three Malaysian public universities. It focuses on three main domains: religious practices, ethnic‒cross relationship and governance. The data of 378 respondents were analyzed using the Statistical Package for the Social Science (SPSS) software version 22. The calculation and the measurement of the index are based on the method and equations used in calculating the index among Malaysian youths in 2015 that were capable of incorporating many domains. All the domains are significant in contributing to ethnic tolerance the composite index value of 4.13 out of 5 was obtained which shows the students are at the level of highly tolerant.

Purpose The effect of using microcrystalline cellulose (MCC) as an additive in coating paint films for non-stick coatings was studied in this work. This paper aims to discuss the benefits of MCC blended in the coating paint film that consists of poly(methyl methacrylate) (PMMA) and dammar. Design/methodology/approach PMMA and dammar mixed at a specific Wt.% ratio with xylene as its solvent. Two sets of mixtures were prepared, where one mixture contained MCC and another, without. The mixtures were applied to metal substrates as coating paint films. The performance of the non-stick coating paint film was observed through the adhesive test between adhesion layers on the coating paint film and also through the cross-hatch test for the adhesion of the non-stick coating paint film to the metal substrate. The results correlate with the surface roughness and glossiness tests. Findings The results showed that for the coating paint films, Sample B consisted of 80:20 Wt.% ratio of PMMA-dammar with an addition of 5 Wt.% MCC had an excellent performance as non-stick coating paint films. The MCC formed microparticles on the surface of the coating paint film sample and this causes the coating paint film samples with MCC to develop a rougher surface compared to the coating paint film without MCC. Sample B coating paint film had the highest average surface roughness (Ra) of 383 µm. The cross-hatch test showed the coating paint film with the addition of MCC had stronger adhesiveness on the substrate’s surface thus prevents the coating from peeling off from the surface. Practical implications The developed coating paint film in this study would be suitable for outdoor applications to prevent illegal advertisements and stickers. Originality/value MCC added to the coating paint film improves the surface performance as a non-stick coating.

Dehydration within low temperature range (30 °C − 100 °C) of Ca2+−Montmorillonite or Ca2+−Mon had caused water removal, where its endothermic from DSC curve reveals the heat of fusion H is about 336.96 J/g. Comparable endothermic within similar temperature range detected in PE-Mon, DPNR-Mon, ENR50-Mon and pPVC-Mon composite profile also indicates the present of interlayer water from Ca2+−Mon particles in the composites. The reduced H about 13% (DPNR-Mon), 32% (PE-Mon), 61% (ENR-50) and 70% (pPVC-Mon) suggests that water removal had occurred during composite fabrication in colloidal systems. XRD analysis however demonstrates that the clay interlayer structure in PE-Mon and DPNR-Mon remain unaffected with similar d001 = 1.46 nm as in pristine Ca2+−Mon. Structural effect from water removal can be seen in the case of ENR50-Mon and pPVC-Mon composites, where the reduced gallery height gives d001 = 1.29 nm and 1.34 nm respectively. Peak intensity behaviors as shown by hydroxyl ((∂HOH) and (νOH)) and silicate (Si-O) bands in FTIR spectra help to explain the observations, particularly the appearance of Si-O band (1017 cm−1) that proves the occurrence of water removal inside the clay composites.

Organophosphorus (OP) compounds are highly toxic synthetic compounds which have been used as pesticides and developed as warfare nerve agents. They represent a threat to both military and civilian populations. OP pesticides affect the nervous system and are thought to have caused at least 5 million deaths since their discovery in the 1930s. At present the treatment of OP nerve agent poisoning commonly involves the use of parenteral oximes. However, the blood brain barrier (BBB) remains a challenge in the delivery of oximes to the central nervous system (CNS). This is because almost all macromolecule drugs (including oximes) fail to pass through the BBB to reach the CNS structures. The presence of a permanent cationic charge in oximes has made these compounds inefficient in crossing the BBB. Thus, oximes are unable to reactivate acetylcholinesterase (AChE) in the CNS. Using current structural and mechanistic understanding of the BBB under both physiological and pathological conditions, it becomes possible to design delivery systems for oximes and other drugs that are able to cross the BBB effectively. This review summarises the recent strategies in the development of oximes which are capable of crossing the BBB to treat OP poisoning. Several new developments using oximes are reviewed along with their advantages and disadvantages. This review could be beneficial for future directions in the development of oxime and other drug delivery systems into the CNS.

This review article provides an overview of the background of nerve agents (NAs) and their hydrolysis products. The analytical techniques that are used for the analysis of hydrolysis products are also discussed. The analysis methods include the chromatographic, mass spectrometric, electrophoretic, and sensing technologies that are currently available for the detection of exposure to a number of hydrolysis products of NAs. All reviewed information was gathered through a detailed search of Scopus, PubMed, and the World Wide Web using relevant keywords, e.g., NA, hydrolysis products, and methylphosphonic acid. Most analyses of NA hydrolysis products still rely on chromatographic techniques such as gas and liquid chromatography. Analyses based on mass spectrometry are now fairly routine and can be further improved by providing analyses with precise and accurate masses and faster scan speeds that provide further gains in sensitivity. Although these techniques have high selectivity and sensitivity, most of them are rarely applied to real samples or suffer from destructive real sample analysis. In addition, there is still a lack of studies on the development of portable sensors for the detection of NA hydrolysis products. Although the analysis of NA hydrolysis products has experienced a transition from qualitative analysis toward rapid and quantitative identification, portable, and fast sensing technologies have not been well established or investigated extensively. In the future, more analysis methods are expected to be developed and may involve the development of sensors and lab-on-chip devices that should address specificity, sensitivity, stability, response time, and repeatability/reproducibility.

Wide availability and diversity of dangerous microbes poses a considerable problem for health professionals and in the development of new healthcare products. Numerous studies have been conducted to develop membrane filters that have antibacterial properties to solve this problem. Without proper protective filter equipment, healthcare providers, essential workers, and the general public are exposed to the risk of infection. A combination of nanotechnology and biosorption is expected to offer a new and greener approach to improve the usefulness of polysaccharides as an advanced membrane filtration material. Nanocellulose is among the emerging materials of this century and several studies had proven its usefulness in filtering microbes. Its high specific surface area enables the adsorption of various microbial species, and its innate porosity can separate various molecules and retain microbial objects. Besides that, the presence of an abundant OH groups in nanocellulose allows its surface modification which can increase its filtration efficiency through the formation of affinity interactions toward microbes. In this review, an update of the most relevant uses of nanocellulose as a new class of membrane filters against microbes is outlined. Key advancements in surface modifications of nanocellulose to enhance its rejection mechanism is also critically discussed. To the best of our knowledge, this is the first review focusing on the development of nanocellulose as a membrane filter against microbes.

The threat of the novel coronavirus (COVID-19) pandemic is worrying as millions of people suffered from this outbreak. The COVID-19 can be airborne by attaching to human nasal or saliva secretion of an infected person or suspended fine particulates in the air. Therefore, in order to minimize the risks associated with this pandemic, an efficient, robust and affordable air‐borne virus removal filters are highly demanded for prevention of spreading viruses in hospitals, transportation hubs, schools, and/or other venues with high human turn‐over. Respirators such as N95, N99 and N100 as well as surgical masks have been widely used. To date, there is no filter standards or special filter technologies tailored for effectively adsorbing the airborne viruses. Studies had shown the electrostatic fibers were capable to entrap the negatively charged viruses including COVID-19. Researchers believed that the positive surface charge of filtration material is an important key to efficiently adsorb the negatively charged viruses. Nanocellulose has emerged as a new class of biobased material with promising potential application in the filtration of viruses. Nanocellulose which is uniform in diameter and has excellent nanofibrillar morphology. To the best of our knowledge, lack of study is done to determine the efficiency of cationic nanocellulose as filtration material of COVID-19.

The search for new compounds other than oxime as potential reactivator that is effective upon organophosphate poisoning treatments is desired. The less efficacy of oxime treatment has been the core factor. Fourteen compounds have been screened via in silico approach for their potential as sarin-inhibited human acetylcholinesterase poisoning antidotes. The selection of the compounds to be synthesized based on this computational screening, reduces the time and cost needed. To perform the docking study of sarin-inhibited acetylcholinesterase and reactivator-sarin inhibited acetylcholinesterase complexations, a bioinformatics tool was used. Estimation of the nucleophilic attack distance and binding energy of fourteen potential compounds with sarin inhibited acetylcholinesterase complexes to determine their antidote capacities was carried out using Autodock. A commercially available antidote, 2-PAM was used for the comparison. The best docked-pose was further examined with molecular dynamics simulation. Apart from being lipophilic, a compound with a carboxylic acid, (R)-Boc-nipecotic acid is shown to exhibit 6.29 kcal/mol binding energy with 8.778 Å distance of nucleophilic attack. The stability and flexibility of the sarin-inhibited acetylcholinesterase, complexed with (R)-Boc-nipecotic acid suggests this compound should be tested experimentally as a new, promising antidote for sarin-inhibited acetylcholinesterase poisoning.

Non-covalent functionalisation of the carbon nanotube (CNT) sidewall through polymer wrapping is the key strategy for improving well-dispersed CNTs without persistent alteration of their electronic properties. In this work, the effect of reaction time on regioregular poly (3-hexylthiophene-2,5-diyl) (P3HT)-wrapped hydroxylated multi-walled CNT (MWCNT-OH) nanocomposites was investigated. Five different reaction times (24, 48, 72, 96, and 120 h) were conducted at room temperature in order to clearly determine the factors that influenced the quality of wrapped MWCNT-OH. Morphological analysis using Field Emission Scanning Electron Microscopic (FESEM) and High-Resolution Transmission Electron Microscope (HRTEM) analysis showed that P3HT successfully wrapped the MWCNT-OH sidewall, evidenced by the changes in the mean diameter size of the nanocomposites. Results obtained from Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS) as well as Thermogravimetric Analysis (TGA) showed a significant effect of the wrapped polymer on the CNT sidewall as the reaction time increased. Overall, the method used during the preparation of P3HT-wrapped MWCNT-OH and the presented results significantly provided a bottom-up approach to determine the effect of different reaction times on polymer wrapping to further expand this material for novel applications, especially chemical sensors.

Carbon nanotubes (CNTs) have been recognised as a promising material in a wide range of applications, from safety to energy-related devices. However, poor solubility in aqueous and organic solvents has hindered the utilisation and applications of carbon nanotubes. As studies progressed, the methodology for CNTs dispersion was established. The current state of research in CNTs either single wall or multiwall/polymer nanocomposites has been reviewed in context with the various types of functionalisation presently employed. Functionalised CNTs have been playing an increasingly central role in the research, development, and application of carbon nanotube-based nanomaterials and systems. The extremely high surface-to-volume ratio, geometry, and hollow structure of nanomaterials are ideal for the adsorption of gas molecules. This offers great potential applications, such as in gas sensor devices working at room temperature. Particularly, the advent of CNTs has fuelled the invention of CNT-based gas sensors which are very sensitive to the surrounding environment. The presence of O2, NH3, NO2 gases and many other chemicals and molecules can either donate or accept electrons, resulting in an alteration of the overall conductivity. Such properties make CNTs ideal for nano-scale gas-sensing materials. Conductive-based devices have already been demonstrated as gas sensors. However, CNTs still have certain limitations for gas sensor application, such as a long recovery time, limited gas detection, and weakness to humidity and other gases. Therefore, the nanocomposites of interest consisting of polymer and CNTs have received a great deal of attention for gas-sensing application due to higher sensitivity over a wide range of gas concentrations at room temperature compared to only using CNTs and the polymer of interest separately.

Since before the British rule, the issues and problems of urban transformation growth have continued until today, especially in rural areas and small towns. Rural communities also have undergone significant transformations in recent decades. There are positive and negative impacts on adaptation the growth of regional development that impact significantly on the rural community, which needs to be addressed to overcome the adverse effects on those that involved. This also included the changes in a case study of rural areas that have been chosen, which is located in sub-district that categorize under rural areas at Johor Bahru due to Iskandar Malaysia region expansions. Furthermore, the developmental transformation has mainly affected the changes in the socio-economic well-being of rural communities. Therefore, the purpose of this paper is to provide an overview of studies on a factor of socio-economic well-being development in rural areas for creating a framework to measure the impact of regional development on the socio-economic well-being of the rural.

In recent years, cellulose nanofiber (CNF) has become an avidly researched material in cutting edge research fields involving prominent researchers, both in academia and industry. This has become an exciting time reaching beyond just scientific curiosity as CNF is beginning to enter various marketplaces. CNF shows unique and potentially useful features, which includes abundance, high specific surface area, renewability, high strength, eco-friendliness and high crystallinity. It is an excellent material for polymer reinforcement. Many studies have been conducted to understand the effects of CNF as a filler in polymer composites. Interestingly, most CNF polymer composites have shown a better mechanical performance compared to the neat base polymer. Thus, this enhances the application of CNF into reinforced polymer composites in several industries such as automotive, packaging, medical implant, electronics, building material and paper. Therefore, in this review, the performances of CNF polymer composites are carefully evaluated. Beyond that, several factors influencing the performance of these composites are discussed.

In this work, bacterial cellulose was obtained from nata de coco. Initially, the samples were subjected to three types of different condition which were raw, chemical treatment and mechanical treatment. Bacterial cellulose was characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffractometer (XRD) and Field Emission Scanning Electron Microscopy (FESEM). Bacterial cellulose met the specifications of pure cellulose either using chemical or mechanical treatments proved by IR spectra reading. XRD results indicated that the crystallinity of chemical treatment bacterial cellulose is higher than the mechanical treatment bacterial cellulose which was 68.6% and 59.5% respectively. The FESEM analysis shows that the size of the bacterial cellulose that obtained from chemical treatment is smaller than mechanical treatments which were 19.42μm and 50.35μm.

Thermal analysis on organically modified Ca2+-montmorillonite (OMON) and its source materials—octadecylamine (ODA) and Ca2+-montmorillonite (Ca2+-Mon)—was studied using thermally stimulated current (TSC) technique. The appearance of ρ MON peak with the T max = 75 °C shows the ability of the developed TSC system to demonstrate the relaxation effects of dehydration in Ca2+-Mon. It appeared within the temperature range of DSC endothermic peak (30–100 °C) where the T mMON = 58 °C. Segmental motions of ODA chains and structural disruptions in the modifier agent compound produced TSC α ODA, ρ ODA and ρ 1ODA peaks that are comparable to thermal transition and endothermic peaks in DSC profile (T gODA, T m1ODA and T m2ODA). The effect of localized motion in ODA chains as revealed by the TSC βOMON peak (T max = −23 °C), however, is absent in the DSC profile of OMON. It shows TSC technique has high sensitivity in detecting various relaxation behaviors at molecular level. More evidences are demonstrated by the ρ OMON (T max = 86 °C) and ρ 1OMON (T max = 105 °C) peak originated from the ODA chains structures. These peaks also confirm the intercalation of the modifier cations inside the Ca2+-Mon gallery.

This review (with 99 refs.) summarizes the progress that has been made in colorimetric (i.e. spectrophotometric) determination of organophosphate pesticides (OPPs) using gold and silver nanoparticles (NPs). Following an introduction into the field, a first large section covers the types and functions of organophosphate pesticides. Methods for colorimetric (spectrophotometric) measurements including RGB techniques are discussed next. A further section covers the characteristic features of gold and silver-based NPs. Syntheses and modifications of metal NPs are covered in section 5. This is followed by overviews on enzyme inhibition-based assays, aptamer-based assays and chemical (non-enzymatic) assays, and a discussion of specific features of colorimetric assays. Several Tables are presented that give an overview on the wealth of methods and materials. A concluding section addresses current challenges and discusses potential future trends and opportunities. Graphical abstractSchematic representation of organophosphate pesticide determinations based on aggregation of nanoparticles (particular silver or gold nanoparticles). This leads to a color change which can be determined visually and monitored by a red shift in the absorption spectrum.

Polymers play a vital role in our daily lives. In various fields such as medical, food industry and automotive applications, the use of biopolymers is commonly used. The most widely used polymers and fillers among biopolymers are polylactic acid (PLA) and cellulose, which are biocompatible and biodegradable due to their eco-friendly properties. Extensive usage of cellulose in various forms has been applied in combination to PLA but there is only a few research that has been done by using the 3D printing method. This paper covers the types of biodegradable biopolymer materials, types of coupling agents and plasticizers, mechanical properties and applications. This paper discusses the types of cellulose ranging from micro to nano, including other types and sources of cellulose that have been researched and are compatible with PLA. In order to generate biocompatible polymers with stronger and better mechanical properties, the findings of these experiments are all tied together. These biopolymers are commonly used in the biomedical industry and are expected to improve their benefits in this field.

Recently, 3D printing techniques for the polymer-based part has become popular in the industry and academic area. Fused deposition modelling (FDM) is one of the most popular methods among 3D printing techniques because of its low cost, ability to fabricate objects with complex structures and geometries, specific functions, ease in processing, safety, reliability, and availability of various thermoplastic materials. This technique’s application is widespread on the electronic application, medical application, and rapid tooling applications. This paper aims to review fused deposition modelling (FDM) 3D printed polymer-based composite techniques for thermal management applications. This paper will provide an overview of fused deposition modelling (FDM) techniques in 3D printing, conducting polymer base and conducting nanofiller additive material used, and current trend research in this area.

Graphene is a carbon that has a unique structure that is excellent in enhancing mechanical, electrical and thermal properties. The fused deposition modelling (FDM) process is a widely used 3D printing method for its low investment and operating cost. Although the FDM process is cheaper and affordable, yet the printed parts are more fragile compare to other 3D printing methods. This paper covers about FDM process and the type of base materials and filler materials. However, the focus is mainly on ABS and graphene. The mechanical properties of ABS/Graphene polymer composite and application of ABS and graphene in the industry were also discussed. Hence, it proved that graphene enhances the properties of ABS. This study is done to improve polymer-based filaments for future references.

Augmented Reality (AR) is the technology that augments the real world by using virtual information of 3D objects overlaid on a view of the real environment. This will create an immersive and intuitive experience. As handheld devices are widely used and now has climb with increasing demand of specifications, its interaction based on touch is a natural and appealing input style for the application of AR. Furthermore, most heuristic studies of interaction in AR usually focus on interactions with AR Target close to the user, generally within arm’s reach. As the user’s move farther away, the effectiveness and usability of the interaction modalities may be different. This study explores handheld AR interaction using real hand gesture at a distance in a room-scale setup. Our aim is to investigate the effectiveness of performing selection while being far away from the 3D object and performing selection task towards object that is being occluded. As object manipulation is one of the key features to explore for mobile handheld AR, we hope our study can give some contribution towards its practical use, especially for real-world assembly structure. Hence, our paper proposes finger ray interaction technique for real hand in handheld AR interface to work for selecting objects at distances ranging from 3 feet to 8 feet and when the object being occluded ranging from 20% to 80% occluded.

A new carbon material viz. graphene has been attracted an increasing research interest owing to its unique electrical and mechanical properties that is useful for the various device applications. The synthesis of graphene from graphene oxide usually involves harmful chemical reducing agents that are toxic and undesirable to human and the environment. By avoiding the use of toxic and environmentally harmful reductants, we report a green approach to effectively reduce graphene oxide to graphene in glucose solution at room temperature. Graphite oxide was synthesized from graphite powder using modified Hummers’ method. Graphite oxide then further exfoliated to graphene oxide by using ultrasonic irradiation. The mild reduction of graphene oxide is carried out by mixing graphene oxide solution with glucose. The reduction time is varied with 15, 30, 45 and 60 minutes. TEM images provide clear evidence for the formation of few layer graphene. Characterization of theresulting glucose reduced graphene oxide by FTIR indicates the partial removal of oxygen-containing functional groups from the surface of graphene oxide and formation of graphene with defects.

Purpose This paper aims to study the colour stability of chlorophyll and the effect of copper (II) nitrate – Cu(NO3)2 – as an additive in natural dye coating films after being exposed to ultraviolet-A (UV-A). Design/methodology/approach The natural dye was extracted from the leaves of Cassia alata L. using absolute ethanol as the solvent. The extract was divided into two parts and, one of it was added with 3 wt.% Cu(NO3)2 as an additive. The polymer blend of poly(methyl methacrylate) (PMMA) and acrylic polyol was used as the coating binder. Both parts of the dye with and without additive were mixed with the blended polymer in a specific ratio. The resulted mixtures were applied as coating films on glass substrates. The colour stability of the coating films on exposure to UV-A with the time of exposure was observed with Commission internationale de l’éclairage (CIE) L*a*b* colour coordinates. The hidden power by the means of reflectivity and glossiness of the coatings was also studied. Statistical standard deviation (STD) was used to analyse the data. Findings The test showed that the coating films containing Cu(NO3)2 had smaller colour differences, (ΔE*) indicating higher colour stability. The analysis on hidden power also showed that the coating film with Cu(NO3)2 was 1.6 times more stable than the film without additive. All the measurements in this study were observed within 35 days of duration. Research limitations/implications This paper implies the potential of using natural dye extracted from Cassia alata L. leaves as a stable dye colourant for coating applications. Practical implications The coating film developed in this study is suitable for glass substrate applications. Originality/value A new method of preparing solvent-based coating film from PMMA–acrylic polyol with chlorophyll colourant is introduced in this study.