One of the major environmental issues of textile industries is the discharge of large quantities of textile effluents, which are source of contamination of water bodies on surface of earth and quality of groundwater. The effluents are toxic, non-biodegradable, carcinogenic and prodigious threats to human and aquatic creatures. Since textile effluents can be treated efficiently and effectively by various advanced oxidation processes (AOPs). Among the various AOPs, cold atmospheric pressure plasma is a promising method among many prominent techniques available to treat the effluents. In this paper, we report about the degradation of simulated effluent, namely Direct Orange-S (DO-S) aqueous solution, using nonthermal atmospheric pressure plasma jet. The plasma treatment of DO-S aqueous solution was carried out as a function of various operating parameters such as potential and treatment time. The change in properties of treated DO-S dye was investigated by means of various analytical techniques such as high-performance liquid chromatography, UV-visible (UV-Vis) spectroscopy and determination of total organic content (TOC). The reactive species present in the samples were identified using optical emission spectrometry (OES). OES results confirmed that the formation of reactive oxygen and nitrogen species during the plasma treatment in the liquid surface was responsible for dye oxidation and degradation. Degradation efficiency, as monitored by color removal efficiency, of 96% could be achieved after 1 h of treatment. Concurrently, the TOC values were found to decrease with plasma treatment, implying that the plasma treatment process enhanced the non-toxicity nature of DO-S aqueous solution. Toxicity of the untreated and plasma-treated dye solution samples was studied using Escherichia coli (E. coli) and Staphylococcus (S. aureus) organisms, which demonstrated that the plasma-treated dye solution was non-toxic in nature compared with untreated one.
Antibacterial coating is important to prevent the colonization of medical devices by biofilm forming bacteria that would cause infection and sepsis in patients. Current coating techniques such as immobilization of antimicrobial compounds, time-releasing antibiotic agents and silver nanoparticles, require multiple processing steps, and they have low efficacy and low stability. We proposed a single-step plasma polymerization of an essential oil known as carvone to produce a moderately hydrophobic antibacterial coating (ppCar) with an average roughness of <1nm. ppCar had a static water contact angle of 78°, even after 10days of air aging and it maintained its stability throughout 24h of LB broth immersion. ppCar showed promising results in the live-dead fluorescence assay and crystal violet assay. The biofilm assay showed an effective reduction of E. coli and S. aureus bacteria by 86% and 84% respectively. ppCar is also shown to rupture the bacteria membrane for its bactericidal effects. The cytotoxicity test indicated that the coating is not cytotoxic to the human cell line. This study would be of interest to researcher keen on producing a bacteria-resistance and biocompatible coating on different substrates in a cost-effective manner.
Consumers' demand is increasing for safe foods without impairing the phytochemical and sensory quality. In turn, it has increased research interest in the exploration of innovative food processing technologies. Cold plasma technology is getting popularity now days owing to its high efficacy in decontamination of microbes in fruit and fruit-based products. As a on-thermal approach, plasma processing maintains the quality of fruits and minimizes the thermal effects on nutritional properties. Cold plasma is also exploited for inactivating enzymes and degrading pesticides as both are directly related with quality loss and presently are most important concerns in fresh produce industry. The present review covers the influence of cold plasma technology on reducing microbial risks and enhancing the quality attributes in fruits.
A novel nitrogen/argon (N2/Ar) radio frequency (RF) plasma functionalized graphene nanosheet/graphene nanoribbon (GS/GNR) hybrid material (N2/Ar/GS/GNR) was developed for simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). Various nitrogen mites introduced into GS/GNR hybrid structure was evidenced by a detailed microscopic, spectroscopic and surface area analysis. Owing to the unique structure and properties originating from the enhanced surface area, nitrogen functional groups and defects introduced on both the basal and edges, N2/Ar/GS/GNR/GCE showed high electrocatalytic activity for the electrochemical oxidations of AA, DA, and UA with the respective lowest detection limits of 5.3, 2.5 and 5.7 nM and peak-to-peak separation potential (ΔEP) (vs Ag/AgCl) in DPV of 220, 152 and 372 mV for AA/DA, DA/UA and AA/UA respectively. Moreover, the selectivity, stability, repeatability and excellent performance in real time application of the fabricated N2/Ar/GS/GNR/GCE electrode suggests that it can be considered as a potential electrode material for simultaneous detection of AA, DA, and UA.
Seven patients with macular hole retinal detachment were treated by intravitreal gas injection with or without release of subretinal fluid. Macular buckling, diathermy, cryopexy, or vitrectomy were not used. The patients were placed prone for eight hours a day until the gas had absorbed. In five of the seven patients the retina became reattached within three days and remained reattached with follow-up periods of three to 22 months (average nine months). It is believed that such detachments are due to vitreoretinal traction and the intravitreal gas bubble relieves this traction. This technique is simple, safe, and does not require costly or sophisticated instruments. It has an added advantage in preserving macular function.
This study investigated the effects of plasma-activated water (PAW) generated with argon at discharge times of 0, 4, 8, 12, and 16 min on the gel properties and structures of chicken myofibrillar protein (MP). Under treatments of 8, 12, and 16 min, both the gel strength and water retention capacity of MP significantly improved, with the gel strength (0.53 N) peaking at 16 min and the lowest cooking loss（30.38 %）. As the treatment time increased from 0 to 16 min, the storage modulus also gradually increased. Results from low-field nuclear magnetic resonance indicated a slowing of water proton mobility, with the proportion of bound water rising from 0.26 % (0 min) to 0.52 % at 16 min. Fourier transform infrared spectroscopy, endogenous fluorescence spectroscopy and scanning electron microscopy confirmed PAW's alteration of MP's secondary and tertiary structures and gel microstructure. Additionally, this study explored the influence of argon PAW's primary active species on MP from a molecular docking perspective·H2O2 could form hydrogen bonds with MP, while O3 and NO2‾could interact via both hydrogen bonds and electrostatic interactions. Thus, PAW can alter protein structure and enhance MP's functional properties, providing insights for applying cold plasma in processing chicken gel products.
River outgassing has proven to be an integral part of the carbon cycle. In Southeast Asia, river outgassing quantities are uncertain due to lack of measured data. Here we investigate six rivers in Indonesia and Malaysia, during five expeditions. CO2 fluxes from Southeast Asian rivers amount to 66.9 ± 15.7 Tg C per year, of which Indonesia releases 53.9 ± 12.4 Tg C per year. Malaysian rivers emit 6.2 ± 1.6 Tg C per year. These moderate values show that Southeast Asia is not the river outgassing hotspot as would be expected from the carbon-enriched peat soils. This is due to the relatively short residence time of dissolved organic carbon (DOC) in the river, as the peatlands, being the primary source of DOC, are located near the coast. Limitation of bacterial production, due to low pH, oxygen depletion or the refractory nature of DOC, potentially also contributes to moderate CO2 fluxes as this decelerates decomposition.
The relationship between greenhouse gas emission and climate change has led to research to identify and manage the natural sources and sinks of the gases. CO2, CH4, and N2O have an anthropic source and of these CO2 is the least effective in trapping long wave radiation. Soil carbon sequestration can best be described as a process of removing carbon dioxide from the atmosphere and relocating into soils in a form that is not readily released back into the atmosphere. The purpose of this study is to estimate carbon stocks available under current conditions in Sarawak, Malaysia. SOC estimates are made for a standard depth of 100 cm unless the soil by definition is less than this depth, as in the case of lithic subgroups. Among the mineral soils, Inceptisols tend to generally have the highest carbon contents (about 25 kg m(-2) m(-1)), while Oxisols and Ultisols rate second (about 10-15 kg m(-2) m(-1)). The Oxisols store a good amount of carbon because of an appreciable time-frame to sequester carbon and possibly lower decomposition rates for the organic carbon that is found at 1m depths. Wet soils such as peatlands tend to store significant amounts of carbon. The highest values estimated for such soils are about 114 kg m(-2) m(-1). Such appreciable amounts can also be found in the Aquepts. In conclusion, it is pertinent to recognize that degradation of the carbon pool, just like desertification, is a real process and that this irreversible process must be addressed immediately. Therefore, appropriate soil management practices should be instituted to sequester large masses of soil carbon on an annual basis. This knowledge can be used effectively to formulate strategies to prevent forest fires and clearing: two processes that can quickly release sequestered carbon to the atmosphere in an almost irreversible manner.
This paper discusses the empirical modeling using system identification technique with a focus on an interacting series process. The study is carried out experimentally using a gaseous pilot plant as the process, in which the dynamic of such a plant exhibits the typical dynamic of an interacting series process. Three practical approaches are investigated and their performances are evaluated. The models developed are also examined in real-time implementation of a linear model predictive control. The selected model is able to reproduce the main dynamic characteristics of the plant in open-loop and produces zero steady-state errors in closed-loop control system. Several issues concerning the identification process and the construction of a MIMO state space model for a series interacting process are deliberated.
Coronavirus 2019 (COVID-19) has globally affected the human mortality rate and economic history of the modern world. According to the World Health Organization, COVID-19 has caused a severe threat to the health of the vulnerable groups, notably the elderly. There is still some disagreements regarding the source of the virus and its intermediate host. However, the spread of this disease has caused most countries to enforce strict curfew laws and close most industrial and recreational centres. This study aims to show the potential positive effects of COVID-19 on the environment and the increase of renewable energy generation in Malaysia. To prevent the spread of this disease, Malaysia enacted the Movement Control Order (MCO) law in March 2020. Implementation of this law led to a reduction in environmental pollution, especially air pollution, in this country. The greenhouse gases (GHG) emission , which was 8 Mt CO2 eq. from January 2020 to March 2020, reduced to <1 Mt CO2 eq. for April and May. The reduction of GHG emission and pollutant gases allowed more sunlight to reach photovoltaic panels, hence increasing the renewable energy generation.
Computed tomography pulmonary angiogram (CTPA) is widely used in the investigation of suspected pulmonary embolism. CTPA is not without adverse effects as it involves intravenous contrast injection and radiation exposure. The annual incidence of pulmonary embolism is 60 – 70 per 100,000 populations and CTPA remains the commonest imaging modality1. This study aims to audit all CTPA performed at Hospital Sultanah Nora Ismail, Batu Pahat, Johor for the entire year of 2018 to illustrate the demographic data, symptoms, risk factors, clinical scoring system applied and patients’ outcome. A retrospective study was conducted to audit all CTPA performed between 1st January to 31st December 2018 via the radiology department electronic records and patients’ records. There were a total of 60 CTPA performed in the entire year of 2018 with 16 positive and 44 negative scans. Among the 16 positive scans, 7 (44%) had a Wells score above 6, 6 (38%) had a Wells score between 2 – 6 and 3 (18%) had a Wells score less than 2. Out of the 16 positive scans, 4 (25%) were known malignancy and 1 was a known case of anti-phospholipid syndrome. All 60 patients had electrographs and arterial blood gases performed prior to CTPA. D dimer was performed in 15 cases (5%). Among the 16 positive scan patients, 4 (25%) passed away during the same admission directly or indirectly related to pulmonary embolism. This annual computed tomography audit report will assist clinicians in making better diagnostic decision when dealing with patients with suspected pulmonary embolism.
In this work, we report the synthesis and characterization of mixed phase Nb1+xS2 nanoflakes prepared by chemical vapor deposition. The as-grown samples show a high density of flakes (thickness ∼50 nm) that form a continuous film. Raman and X-ray diffraction data show that the samples consist of both 2H and 3R phases, with the 2H phase containing a high concentration of Nb interstitials. These Nb interstitials sit in between the NbS2 layers to form Nb1+xS2. Cross-sectional Energy Dispersive Spectroscopy analysis with transmission electron microscopy suggests that the 2H Nb1+xS2 region is found in thinner flakes, while 3R NbS2 is observed in thicker regions of the films. The evolution of the phase from 2H Nb1+xS2 to 3R NbS2 may be attributed to the change of the growth environment from Nb-rich at the start of the growth to sulfur-rich at the latter stage. It was also found that the incorporation of Nb interstitials is highly dependent on the temperature of the NbCl5 precursor and the position of the substrate in the furnace. Samples grown at high NbCl5 temperature and with substrate located closer to the NbCl5 source show higher incorporation of Nb interstitials. Electrical measurements show linear I-V characteristics, indicating the metallic nature of the Nb1+xS2 film with relatively low resistivity of 4.1 × 10-3Ω cm.
Industrial, and municipal wastes are part of the main sources of environmental hazards as well as groundwater and surface water pollutions. If not well composed, treated, and safely disposed, it could permeate through the subsurface lithologies by reaching down to the underground water aquifers, particularly in zones of unprotected aquifer units. Pollutants, most especially the landfills leachates that encompassed organic contaminants, ammonia, nitrates, total nitrogen, suspended solids, heavy metals and soluble inorganic salts, i.e., soluble nitrogen, sulphur compound, sulphate and chlorides, could posed undesirable environmental impacts due to inappropriate disposals that may give rise to gaseous fumes and leachate formations. An electrical resistivity geophysical technique utilizing the RES2D no-invasive, cost-effective and rapid method of data collection was integrated with the 3D Oasis Montaj software to approximate the volume of the generated rectangular prism model of the contaminants delineated from mixtures of the industrial, and municipal wastes plumes to be 312,000 m 3.
Fresh-cut pineapple has experienced an increase in demand due to its great health benefits and is rich in vitamins A, B and C. Moreover, pineapple is known as a source of the enzyme bromelain, which has therapeutic applications, such as reducing inflammation, improving digestion and treating osteoarthritis. However, bromelain generally affects the pineapple’s flavour and is less preferred by consumers due to the uncomfortable prickling and tingling sensations it brings. In the present study, two types of gases and their combination, nitrogen (N2) and carbon dioxide (CO2), were used to evaluate their impacts on reducing the tingling and prickling sensations, as well as maintaining the postharvest qualities of fresh-cut pineapple stored at 5°C for 12 days. The parameters being evaluated were the bromelain enzyme activity, flesh colour, ascorbic acid concentration, flesh firmness, soluble solids concentration (SSC), titratable acidity (TA) and sensory evaluation. No significant differences were recorded for all parameters tested. Based on the sensory evaluations, all the attributes, such as colour, aroma, texture, sweetness, sourness, tingling and prickling sensations, and overall acceptance were not affected by the different gases application. Even though no apparent effect was observed, the 30 panellists preferred the aforementioned attributes, except sourness. In conclusion, the fumigation treatments with N2 and CO2 gases were not effective in reducing the tingling and prickling sensations of pineapples cv. Morris.
Although carbon dioxide (CO2) is well known as one of the major green-house gases, it is also an economical C1 resource. Thus, CO2has been regarded as an appealing starting material for the synthesis of polymers, like polycarbonates by the reaction with epoxides. Herein the reaction between natural epoxidized soybean oil (ESO), propylene oxide (PO) and CO2under high pressure (4.0MPa) with the presence of Co-Zn double metal cyanide (Co-Zn DMC) catalyst was studied. Temperature and reaction time were varied accordingly and the products obtained were characterized by FTIR, GPC and1H NMR. The results obtained indicate the formation of polycarbonates in the samples collected with yields vary from 60 to 85%. The number average molecular weight (Mn) of the resultant polymer prepared at reaction temperature of 80°C and reaction time of 6h can reach up to 6498g/mol.
Local exhaust ventilation (LEV) is used in industries to capture contaminants such as gases, dusts, mists, vapours or fumes out of workstations to protect occupants’ exposure to contaminants. LEV is allocated and installed by employers, however it doesn’t work accordingly. LEV design is often overlooked and underappreciated. Effectiveness of LEV system can be achieved if more attention is focused to proper design of LEV system. To solve this issue, computational fluid dynamics (CFD) can be performed. CFD is a software tool to predict and simulate fluid dynamic phenomena. CFD is used to forecast or reconstruct the behaviour of an engineering product under assumed or measure boundary conditions. However, CFD is just a prediction tool, which can lead to inaccuracy of predicting airflow due to problems with pre-processing, solver and post-processing with parameter from actual experimental results. Therefore, validation is needed to help minimizing percentage error of CFD methods. In this research, measurements of airflow parameter of LEV system at National Institute of Occupational Safety and Health (NIOSH) Bangi, Selangor were conducted. Control Speed panel found at NIOSH Bangi, which is used to increase or decrease speed of fan, was performed using Control Speed of 20%, 40% 60% and 80%. Upon validation, average absolute error obtained from four different control speeds ranges from 3.372% to 4.862%. Validity of CFD modelling is acceptable, which is less than 5% and good agreement is achieved between actual experimental results and CFD simulation results. Therefore, it can be concluded that CFD software tool can be performed to simulate air velocity in LEV system. CFD methods can save labour costs and time consumption when it is used during earliest stage of LEV design, before actual construction is implemented. The outcome of this paper can be used as a baseline for factories equipped with LEV system to protect occupants’ exposure to contaminants.
Template-assisted growth is an important nanoelectrochemical deposition technique for synthesizing one-dimensional (1-D) nanostructures with uniformly well-controlled shapes and sizes. A good template with well-defined dimensions is imperative for realizing this task. Porous anodic alumina (PAA) has been a favorable candidate for this purpose as it can be tailor-made with precise pore geometries, such as pore length and diameter as well as inter-pore distances, via the anodisation of pure aluminium. This paper reports the fabrication of PAA templates and electrochemical synthesis of functional nanostructures in the form of nanowires using PAA templates as scaffolds. Axial heterostructured and homogeneous nanowires formed by engineering materials configuration via composition and/or layer thickness variations were fabricated for different functionalities. X-ray diffraction and imaging techniques were used to elucidate the microstructures, morphologies and chemical compositions of the nanowires produced. Due to their large surface area-to-volume ratios, and therefore high sensitivities, these functional nanostructures have useful applications as critical components in nanosensor devices and various areas of nanotechnology. Potential applications include as hydrogen gas sensors in nuclear power plant for monitoring structural integrity of reactor components and containment building, as well as environmental monitoring of air pollution and leakages of toxic gases and chemicals.
Feasibility studies on the vitrification of spent ion exchange resins combined with glass cullet powder have been conducted using a High Temperature Test Furnace. Bottle glass cullet powder was used as matrix material to convert the ash of the spent resins into a glass. Vitrificat ion of spent ion exchange resins presents a reasonable disposal alternative, because of its inherent organic destruction capabilities, the volume reduction levels obtainable, and the durable product that it yields. In this study, the spent ion exchange resin from the PUSPATI TRIGA reactor of Nuclear Malaysia was combusted in a lab scale combustor and the resulting ash was vitrified together with glass cullet powder in a high temperature furnace to produce a stable spent resin ash embedded in glass. The factors affecting this immobilized waste, such as thermal stability, radiological stability and leachability have all been investigated. However, the outcome of these tests, which include the radionuclide activity concentration in the slag, the optimum conditioning temperature - in relation with volume reduction during vitrification - and the volume mixing ratio of matrix material were reported. It was found that the radionuclides present in spent resins were 54 Mn, 60 Co and 152Eu. The elementary chemical composition (carbon, hydrogen, nitrogen and sulphur) of spent resins was 27.6% C, 5.68% H, 2.04% N and 4.20% S, respectively. The maximum calorific value of spent resins was 1735 kJ/kg. The average activity concentrations of 54 Mn and 60Co in ash at 200oC were 9,411 ± 243 Bq/Kg and 12,637± 201 Bq/Kg. flue gases containing CO2, CO, SO2 and NO started to be emitted above 200oC. The optimum conditioning temperature was also the highest tested, i.e. 900oC in 45 minutes, and the best mixing ratio ash to matrix material was also the highest, ie 1:9. Finally, the leaching analysis of slag at 900oC in 45 minutes showed that the leaching activity of 60Co was below 0.5 Bq/mL.