Azobenzene-based gel coated fibre Bragg grating sensor for moisture measurement

A fibre Bragg grating sensor is coated with a novel polymer gel in order to investigate its suitability for nondestructive measurement of moisture in materials that can potentially lose their integrity due to moisture ingress. Absorption and desorption of moisture lead to swelling/shrinkage of an azobenzene-based gel, which induces a strain in the Bragg grating resulting in wavelength shifts. The results demonstrated that the amount of wavelength shift is linearly dependent on the amount of water ingress by the gel. The performance of the proposed optical fibre moisture sensor was found to be repeatable with no detectable hysteresis and has the potential to offer a low-cost route for monitoring moisture content

Investigation of chemical components and purities of eight malaysian honeys as compared to manuka honey

Introduction: Malaysia, a tropical country rich with flora and fauna has many different types of honeys. Although honey is produced and is greatly consumed in Malaysia, there is a lack of information on the chemical composition of these honeys. Thus, the present study was aimed to investigate the chemical composition (physical, chemical, antioxidant parameters, minerals, trace elements, volatile compounds and sugar content) of eight different Malaysian honeys (acacia, pineapple, gelam, longan, borneo, rubber tree, sourwood and tualang) compared to manuka honey. Methods: Different physical and antioxidant parameters were measured using spectrophotometric techniques while phenolic acid composition was determined by high performance liquid chromatography. Minerals and trace elements were determined using atomic absorption spectrometry. Gas chromatography quadrupole time-of-flight mass spectrometry (GC-QTOF-MS) was used for the first time to analyse honey volatiles and subsequently a novel dispersive liquid-liquid microextraction (DLLME) method was developed to analyse volatiles. Sugar analysis was performed by GC-MS. Results and discussions: The physical parameters of the investigated honeys were within the limit recommended by International Honey Commission. The mean concentration of phenolics (325.59 ± 168.45 mggalicacid/kg) and flavonoids (62.52 ± 56.06 mgcatechin/kg), DPPH radical scavenging activity (43.02 ± 14.03%) and ferric reducing power was 329.70 ± 209.16 μM Fe (II)/100 g. Benzoic acid was the most abundant phenolic compounds (75%) among the phenolic acids followed by caffeic acid, catechin, myricetin, gallic acid and naringenin. High mineral contents were observed in the investigated honeys with K, Na, Fe and Ca being the most abundant elements (mean 1466.01, 230.15, 133.39 and 144.48 mg/kg, respectively). Overall, the trace elements were within the recommended limits with no pesticide residues detected in any of the honey samples indicating their good qualities. Following analysis using headspace (HS) solid-phase microextraction (SPME), accurate mass capabilities of GC-QTOF-MS evaluated for compounds identification showed a relatively narrow mass window (0.005 Da). Finally, a novel DLLME method was developed and optimised to analyse honey volatiles. The whole sample preparation process was completed in only approximately 10 min, with a total consumption of organic solvents below 4 mL, relative standard deviations lower than 12% and approximately 78 organic compounds identified in the obtained extracts. Several sugars were identified and quantified in honeys. Conclusion: Sourwood, longan and tualang honeys have higher number of phenolic acids, flavonoids with superior antioxidant potentials when compared to other Malaysian honeys and manuka honey. Overall, the results of this research indicate that Malaysian honeys are of good qualities

Ultrasonic studies of solid azobenzene decorated polymer thin films

This work investigates the effect of ultrasound on switching of cis azobenzene isomers to their trans counterparts in solid films of methyl methacrylate and methacryloyloxyazobenzene copolymers [P(MMA/MOAB)]. UV/Vis and 1H NMR spectroscopy demonstrates that 46% of the cis isomer converts to the trans form purely by ultrasonic agitation and 46% converts to the trans isomer by localised ultrasound induced heating effects. Comparative studies of isomerisation by ultrasound wave, heat and visible irradiation shows that ultrasound exposure requires a longer time to switch the cis to trans conformation. The estimated activation energy for the cis to trans conversion in the solid polymer films is shown to be comparable to previous values of azobenzene isomerization, indicating that incorporation of the chromophore in a polymeric system affects the kinetics of transition, but not the barriers to conformational change

High latency unmanned ground vehicle teleoperation enhancement by presentation of estimated future through video transformation

Long-distance, high latency teleoperation tasks are difficult, highly stressful for teleoperators, and prone to over-corrections, which can lead to loss of control. At higher latencies, or when teleoperating at higher vehicle speed, the situation becomes progressively worse. To explore potential solutions, this research work investigates two 2D visual feedback-based assistive interfaces (sliding-only and sliding-and-zooming windows) that apply simple but effective video transformations to enhance teleoperation. A teleoperation simulator that can replicate teleoperation scenarios affected by high and adjustable latency has been developed to explore the effectiveness of the proposed assistive interfaces. Three image comparison metrics have been used to fine-tune and optimise the proposed interfaces. An operator survey was conducted to evaluate and compare performance with and without the assistance. The survey has shown that a 900ms latency increases task completion time by up to 205% for an on-road and 147 % for an off-road driving track. Further, the overcorrection-induced oscillations increase by up to 718 % with this level of latency. The survey has shown the sliding-only video transformation reduces the task completion time by up to 25.53 %, and the sliding-and-zooming transformation reduces the task completion time by up to 21.82 %. The sliding-only interface reduces the oscillation count by up to 66.28 %, and the sliding-and-zooming interface reduces it by up to 75.58 %. The qualitative feedback from the participants also shows that both types of assistive interfaces offer better visual situational awareness, comfort, and controllability, and significantly reduce the impact of latency and intermittency on the teleoperation task

Closed vessel burning behavior and ballistic properties of artificially-degraded spherical double-base propellants stabilized with diphenylamine

The purpose of solid propellants is to generate gas, which expands to accelerate (and spin, in the case of rifled barrels) a gun projectile so that it achieves the desired launch velocity at the muzzle. Some of the important properties of a propellant are the burning rate and vivacity, both of which strongly influence gun performance and projectile range. However, nitrate ester propellants undergo physical and chemical degradation during storage and this can change the burning rate and/or vivacity, either reducing the propulsive efficiency or increasing the safety risk to the operator during transportation and handling. Here we report the effect of aging on the burning rate and vivacity of spherical double-base propellants containing diphenylamine (DPA) as the main stabilizer. We tested three sets of propellants that were artificially aged at 80 °C for 5.3, 10.6 and 21.6 days, equivalent to 5, 10 or 20 years of aging at 25 °C according to STANAG 4582. It was found that DPA was progressively lost from the propellants during aging, with the greatest loss observed in propellants aged for the longest time. The DPA was able to fulfil its stabilisation role of propellant when NG was up to 14%, however, failed to stabilize when the nitroglycerin content was nearer to 20%. Aging caused changes in the burning rate and vivacity compared to the unaged propellant batch. The burning rate of propellant containing ˜20% nitroglycerin exceeds the burning rates of samples containing 12–14% nitroglycerin. The limited role of DPA as a stabilizer for double-base propellants is discussed. The DPA stabilized double base propellant may undergo significant changes during storage, making them unsuitable for their designated use

Determination of Mineral, Trace Element, and Pesticide Levels in Honey Samples Originating from Different Regions of Malaysia Compared to Manuka Honey

Thepresent study was undertaken to determine the content of six minerals, five trace elements, and ten pesticide residues in honeys originating from different regions of Malaysia. Calcium (Ca), magnesium (Mg), iron (Fe), and zinc (Zn) were analyzed by flame atomic absorption spectrometry (FAAS), while sodium (Na) and potassium (K) were analyzed by flame emission spectrometry (FAES). Trace elements such as arsenic (As), lead (Pb), cadmium (Cd), copper (Cu), and cobalt (Co) were analyzed by graphite furnace atomic absorption spectrometry (GFAAS) following the microwave digestion of honey. High mineral contents were observed in the investigated honeys with K, Na, Ca, and Fe being the most abundant elements (mean concentrations of 1349.34, 236.80, 183.67, and 162.31mg/kg, resp.).The concentrations of the trace elements were within the recommended limits, indicating that the honeys were of good quality. Principal component analysis reveals good discrimination between the different honey samples. The pesticide analysis for the presence of organophosphorus and carbamates was performed by high performance liquid chromatography (HPLC). No pesticide residues were detected in any of the investigated honey samples, indicating that the honeys were pure. Our study reveals that Malaysian honeys are rich sources of minerals with trace elements present within permissible limits and that they are free from pesticide contamination

Determination of Carbamate and Organophosphorus Pesticides in Vegetable Samples and the Efficiency of Gamma-Radiation in Their Removal

In the present study, the residual pesticide levels were determined in eggplants (Solanummelongena)

MEDICINAL PLANTS AND FORMULATIONS USED BY THE SOREN CLAN OF THE SANTAL TRIBE IN RAJSHAHI DISTRICT, BANGLADESH FOR TREATMENT OF VARIOUS AILMENTS

The Santals form the largest tribal community in northern Bangladesh reside primarily in Rajshahi and Rangpur Divisions, where they live in the districts of Rajshahi, Rangpur, Thakurgaon, Dinajpur, and Panchagarh. Although they are fast losing their traditional medicinal practices, they still have their own medicinal practitioners who rely mostly on medicinal plants for treatment of a variety of ailments. The traditional medicinal practices vary quite extensively between the twelve clans of the Santals. The objective of the present study was to conduct an ethnomedicinal survey amongst the Soren clan of the Santal community residing in two villages of Tanor Santal Para in Rajshahi district to collect information on their use of medicinal plants. Interviews were conducted of the two existing Santal traditional medicinal practitioners of the Soren clan with the help of a semi-structured questionnaire and using the guided field-walk method. Plant specimens as pointed out by the practitioners were collected and pressed on the field and identification completed at the Bangladesh National Herbarium. Information on 53 medicinal plants distributed into 32 families was obtained in this survey. Ailments treated by these plants included skin disorders, respiratory tract disorders, gastro-intestinal disorders, sexual dysfunctions, sexually transmitted diseases, diabetes, helminthiasis, pain, urinary problems, filariasis, leprosy, tuberculosis, epilepsy, snake bite, enlarged heart, and paralysis. The medicinal plants used by the Santals merit further scientific studies for some of their formulations are used to treat diseases like diabetes, paralysis, enlarged heart, tuberculosis, and filariasis for which modern medicine has no known cure or medicines have developed resistant vectors