Displaying publications 281 - 300 of 515 in total

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  1. Fulltext Monitoring of CO2 Absorption Solvent in Natural Gas Process Using Fourier Transform Near-Infrared Spectrometry
    Yusop Nurida M, Norfadilah D, Siti Aishah MR, Zhe Phak C, Saleh SM
    Int J Anal Chem, 2020;2020:9830685.
    PMID: 32089691 DOI: 10.1155/2020/9830685
    The analytical methods for the determination of the amine solvent properties do not provide input data for real-time process control and optimization and are labor-intensive, time-consuming, and impractical for studies of dynamic changes in a process. In this study, the potential of nondestructive determination of amine concentration, CO2 loading, and water content in CO2 absorption solvent in the gas processing unit was investigated through Fourier transform near-infrared (FT-NIR) spectroscopy that has the ability to readily carry out multicomponent analysis in association with multivariate analysis methods. The FT-NIR spectra for the solvent were captured and interpreted by using suitable spectra wavenumber regions through multivariate statistical techniques such as partial least square (PLS). The calibration model developed for amine determination had the highest coefficient of determination (R2) of 0.9955 and RMSECV of 0.75%. CO2 calibration model achieved R2 of 0.9902 with RMSECV of 0.25% whereas the water calibration model had R2 of 0.9915 with RMSECV of 1.02%. The statistical evaluation of the validation samples also confirmed that the difference between the actual value and the predicted value from the calibration model was not significantly different and acceptable. Therefore, the amine, CO2, and water models have given a satisfactory result for the concentration determination using the FT-NIR technique. The results of this study indicated that FT-NIR spectroscopy with chemometrics and multivariate technique can be used for the CO2 solvent monitoring to replace the time-consuming and labor-intensive conventional methods.
    Matched MeSH terms: Carbon Dioxide
  2. Recent progress on CO-rich syngas production via CO2 gasification of various wastes: A critical review on efficiency, challenges and outlook
    Chan YH, Syed Abdul Rahman SNF, Lahuri HM, Khalid A
    Environ Pollut, 2021 Mar 01;278:116843.
    PMID: 33711630 DOI: 10.1016/j.envpol.2021.116843
    Carbon monoxide (CO) is a highly valuable component of syngas which could be used to synthesize various chemicals and fuels. Conventionally, syngas is derived from fossil-based natural gas and coal which are non-renewable. To curb the problem, CO2 gasification offers a win-win solution in which CO2 is converted with wastes to CO, achieving carbon emission mitigation and addressing waste disposal issue simultaneously. In this review, gasification of various wastes by CO2 with particular focus given to generation of CO-rich syngas is presented and critically discussed. This includes the effects of operating parameters (temperature, pressure and physicochemical properties of feedstocks) and advanced CO2 gasification techniques (catalytic CO2 gasification, CO2 co-gasification and microwave-driven CO2 gasification). Furthermore, associated technological challenges are highlighted and way forward in this field are proposed.
    Matched MeSH terms: Carbon Dioxide
  3. Fulltext School indoor air quality and health risk on the junior high schools students in Depok, Indonesia
    Sasnila Pakpahan, Bambang Wispriyono, Budi Hartono, Juliana Jalaludin
    Malaysian Journal of Medicine and Health Sciences, 2019;15(204):114-123.
    MyJurnal
    Introduction: School environment represents an important microenvironment for students who spend 6-8 hours in classrooms. Indoor air quality is linked to several respiratory diseases in the school age group. This research aims to study indoor air quality of schools at different environmental characteristic and assess its health risks to students. Methods: This research measured air quality (PM2.5, PM10, CO2 , and HCHO) in three junior high schools and followed by health risk assessment. Results: This research found that the mean or median level of indoor PM2.5 and PM10 in all three schools exceeded the standard value with health risks (HQ> 1) for PM2.5 in all three schools and PM10 in two schools. Whereas carbon dioxide and formaldehyde concentrations were still safe and did not inflict health risks (HQ < 1). The scenario for managing the health risk of PM2.5 and PM10 exposure was to control the exposure at a safe threshold of PM2.5 0.035 mg/m3 ; 0.043 mg/m3 and PM10 0.144 mg/m3 for most of the population at normal school time. Conclusion: It was concluded that the level of indoor particulate matters indicates poor indoor air quality in all three schools at different environmental characteristic and inflicts health risk on students so that the health risk management is required.
    Matched MeSH terms: Carbon Dioxide
  4. Fulltext Synthesis, Characterization and the Solvent Effects on Interfacial Phenomena of Jatropha Curcas Oil Based Non-Isocyanate Polyurethane
    Haniffa MACM, Ching YC, Chuah CH, Kuan YC, Liu DS, Liou NS
    Polymers (Basel), 2017 May 01;9(5).
    PMID: 30970841 DOI: 10.3390/polym9050162
    Non-isocyanate polyurethane (NIPU) was prepared from Jatropha curcas oil (JCO) and its alkyd resin via curing with different diamines. The isocyanate-free approach is a green chemistry route, wherein carbon dioxide conversion plays a major role in NIPU preparation. Catalytic carbon dioxide fixation can be achieved through carbonation of epoxidized derivatives of JCO. In this study, 1,3-diaminopropane (DM) and isophorone diamine (IPDA) were used as curing agents separately. Cyclic carbonate conversion was catalyzed by tetrabutylammonium bromide. After epoxy conversion, carbonated JCO (CJCO) and carbonated alkyd resin (CC-AR) with carbonate contents of 24.9 and 20.2 wt %, respectively, were obtained. The molecular weight of CJCO and CC-AR were determined by gel permeation chromatography. JCO carbonates were cured with different amine contents. CJCO was blended with different weight ratios of CC-AR to improve its characteristics. The cured NIPU film was characterized by spectroscopic techniques, differential scanning calorimetry, and a universal testing machine. Field emission scanning electron microscopy was used to analyze the morphology of the NIPU film before and after solvent treatment. The solvent effects on the NIPU film interfacial surface were investigated with water, 30% ethanol, methyl ethyl ketone, 10% HCl, 10% NaCl, and 5% NaOH. NIPU based on CCJO and CC-AR (ratio of 1:3) with IPDA crosslink exhibits high glass transition temperature (44 °C), better solvent and chemical resistance, and Young's modulus (680 MPa) compared with the blend crosslinked with DM. Thus, this study showed that the presence of CC-AR in CJCO-based NIPU can improve the thermomechanical and chemical resistance performance of the NIPU film via a green technology approach.
    Matched MeSH terms: Carbon Dioxide
  5. Impact of photoluminescent carbon quantum dots on photosynthesis efficiency of rice and corn crops
    Tan TL, Zulkifli NA, Zaman ASK, Jusoh MB, Yaapar MN, Rashid SA
    Plant Physiol Biochem, 2021 May;162:737-751.
    PMID: 33799185 DOI: 10.1016/j.plaphy.2021.03.031
    Photosynthesis is one of the most fundamental biochemical processes on earth such that it is vital to the existence of most lives on this planet. In fact, unravelling the potentials in enhancing photosynthetic efficiency and electron transfer process, which are thought to improve plant growth is one of the emerging approaches in tackling modern agricultural shortcomings. In light of this, zero-dimensional carbon quantum dots (CQD) have emerged and garnered much interest in recent years which can enhance photosynthesis by modulating the associated electron transfer process. In this work, CQD was extracted from empty fruit bunch (EFB) biochar using a green acid-free microwave method. The resulting CQD was characterized using HRTEM, PL, UV-Vis and XPS. Typical rice (C3) and corn (C4) crops were selected in the present study in order to compare the significant effect of CQD on the two different photosynthetic pathways of crops. CQD was first introduced into crop via foliar spraying application instead of localised placement of CQD before seedling development. The influence of CQD on the photosynthetic efficiency of rice (C3) and corn (C4) leaves was determined by measuring both carbon dioxide conversion and the stomatal conductance of the leaf. As a result, the introduction of CQD greatly enhanced the photosynthesis in CQD-exposed crops. This is the first study focusing on phylogenetically constrained differences in photosynthetic responses between C3 and C4 crops upon CQD exposure, which gives a better insight into the understanding of photosynthesis process and shows considerable promise in nanomaterial research for sustainable agriculture practices.
    Matched MeSH terms: Carbon Dioxide
  6. Inventory routing problem with carbon emission consideration
    Nur Arina Bazilah Aziz
    MATEMATIKA, 2019;35(1):39-49.
    MyJurnal
    Inventory Routing Problem (IRP) has been continuously developed and improved due to pressure from global warming issue particularly related to greenhouse gases (GHGs) emission. The burning of fossil fuel for transportations such as cars, trucks, ships, trains, and planes primarily emits GHGs. Carbon dioxide (CO2) from burning of fossil fuel to power transportation and industrial process is the largest contributor to global GHGs emission. Therefore, the focus of this study is on solving a multi-period inventory routing problem (MIRP) involving carbon emission consideration based on carbon cap and offset policy. Hybrid genetic algorithm (HGA) based on allocation first and routing second is used to compute a solution for the MIRP in this study. The objective of this study is to solve the proposed MIRP model with HGA then validate the effectiveness of the proposed HGA on data of different sizes. Upon validation, the proposed MIRP model and HGA is applied on real-world data. The HGA is found to be able to solve small size and large size instances effectively by providing near optimal solution in relatively short CPU execution time.
    Matched MeSH terms: Carbon Dioxide
  7. Gasification of refuse-derived fuel from municipal solid waste for energy production: a review
    Yang Y, Liew RK, Tamothran AM, Foong SY, Yek PNY, Chia PW, et al.
    Environ Chem Lett, 2021 Jan 13.
    PMID: 33462541 DOI: 10.1007/s10311-020-01177-5
    Dwindling fossil fuels and improper waste management are major challenges in the context of increasing population and industrialization, calling for new waste-to-energy sources. For instance, refuse-derived fuels can be produced from transformation of municipal solid waste, which is forecasted to reach 2.6 billion metric tonnes in 2030. Gasification is a thermal-induced chemical reaction that produces gaseous fuel such as hydrogen and syngas. Here, we review refuse-derived fuel gasification with focus on practices in various countries, recent progress in gasification, gasification modelling and economic analysis. We found that some countries that replace coal by refuse-derived fuel reduce CO2 emission by 40%, and decrease the amount municipal solid waste being sent to landfill by more than 50%. The production cost of energy via refuse-derived fuel gasification is estimated at 0.05 USD/kWh. Co-gasification by using two feedstocks appears more beneficial over conventional gasification in terms of minimum tar formation and improved process efficiency.
    Matched MeSH terms: Carbon Dioxide
  8. Fulltext TECHNO-ECONOMIC FEASIBILITY STUDY OF AN OFF-GRID HYBRID POWER SYSTEM FOR AN AQUA-TOURISM RESORT IN TERENGGANU, MALAYSIA
    MUHAMMAD FAKHRURAZI MD YUNOS, NUR FARIZAN MUNAJAT, WAN MARIAM WAN MUDA
    UMT Journal of Undergraduate Research, 2019;1(2):103-110.
    MyJurnal
    This study focused on feasibility analysis of hybrid electrification system for an aqua-tourism resort located remotely from the grid connection in Terengganu. There were four standalone systems used in this study: diesel/PV/biomass/battery, diesel/PV/battery, biomass/diesel/battery, and diesel only. The design and analysis of these systems were done using Hybrid Optimization of MultipleEnergy Resources (HOMER) software. The results showed that the diesel/PV/battery system was the optimum solution in terms of net present cost (NPC) and cost of energy (COE). This system comprises 20 % of PV penetration with NPC and COE of USD 57,823 (RM 241, 729.90) and 0.428 USD/kWh (1.79 RM/kWh), respectively. Meanwhile, the diesel/PV/biomass/battery system with NPC of USD 65,388 (RM 273, 355.49) and COE of 0.484 USD/kWh (2.02 RM/kWh) was found to be the best among all systems in terms of greenhouse emissions. This system was able to reduce almost 70 % of carbon dioxide if compared with diesel only system and about 15 % lower than the diesel/PV/battery system with a renewable energy fraction of 44 %.
    Matched MeSH terms: Carbon Dioxide
  9. Soft computing-based modeling and emission control/reduction of a diesel engine fueled with carbon nanoparticle-dosed water/diesel ‎emulsion fuel
    Atarod P, Khlaife E, Aghbashlo M, Tabatabaei M, Hoang AT, Mobli H, et al.
    J Hazard Mater, 2021 04 05;407:124369.
    PMID: 33160782 DOI: 10.1016/j.jhazmat.2020.124369
    This study was set up to model and optimize the performance and emission characteristics of a diesel engine fueled with carbon nanoparticle-dosed water/‎diesel emulsion fuel using a combination of soft computing techniques. Adaptive neuro-fuzzy inference system tuned by particle ‎swarm algorithm was used for modeling the performance and emission parameters of the engine, while optimization of the engine operating parameters and the fuel composition was conducted via multiple-objective particle ‎swarm algorithm. The model input variables were: injection timing (35-41° CA BTDC), engine load (0-100%), nanoparticle dosage (0-150 μM), and water content (0-3 wt%). The model output variables included: brake specific fuel consumption, brake thermal efficiency, as well as carbon monoxide, carbon dioxide, nitrogen oxides, and unburned hydrocarbons emission concentrations. The training and testing of the modeling system were performed on the basis of 60 data patterns obtained from the experimental trials. The effects of input variables on the performance and emission characteristics of the engine were thoroughly analyzed and comprehensively discussed as well. According to the experimental results, injection timing and engine load could significantly affect all the investigated performance and emission parameters. Water and nanoparticle addition to diesel could markedly affect some performance and emission parameters. The modeling system could predict the output parameters with an R2 > 0.93, MSE carbon dioxide, carbon monoxide, nitrogen oxides, and unburned hydrocarbon emission concentrations ‎were found to be ‎7.26‎ vol%‎, ‎0.46 vol%‎, ‎95.7‎ ppm, and‎ 36.2 ppm, respectively, under the ‎selected optimal operating conditions while the quantity of brake thermal efficiency was found at an acceptable level (‎34.0‎%).‎ In general, the applied soft computing combination appears to be a promising approach to model and optimize operating parameters and fuel composition of diesel engines.
    Matched MeSH terms: Carbon Dioxide
  10. Sustainable mixed matrix membranes containing porphyrin and polysulfone polymer for acid gas separations
    Saqib S, Rafiq S, Muhammad N, Khan AL, Mukhtar A, Ullah S, et al.
    J Hazard Mater, 2021 06 05;411:125155.
    PMID: 33858108 DOI: 10.1016/j.jhazmat.2021.125155
    The synergetic effect of nitrogen-rich and CO2-philic filler and polymer in mixed matrix-based membranes (MMMs) can separate CO2 competently. The introduction of well-defined nanostructured porous fillers of pores close to the kinetic diameter of the gas molecule and polymer matrix compatibility is a challenge in improving the gas transportation characteristics of MMMs. This study deals with the preparation of porphyrin filler and the polysulfone (PSf) polymer MMMs. The fillers demonstrated uniform distribution, uniformity, and successful bond formation. MMMs demonstrated high thermal stability with a glass transition temperature in the range of 480-610 °C. The porphyrin filler exhibited microporous nature with the presence of π-π bonds and Lewis's basic functionalities between filler-polymer resulted in a highly CO2-philic structure. The pure and mixed gas permeabilities and selectivity were successfully improved and surpass the Robeson's upper bound curve's tradeoff. Additionally, the temperature influence on CO2 permeability revealed lower activation energies at higher temperatures leading to the gas transport facilitation. This can be granted consistency and long-term durability in polymer chains. These results highlight the unique properties of porphyrin fillers in CO2 separation mixed matrix membranes and offer new knowledge to increase comprehension of PSf performance under various contents or environments.
    Matched MeSH terms: Carbon Dioxide
  11. Effect of short-term ketogenic diet on end-tidal carbon dioxide
    Vijayam B, Malarvili MB, Md Shakhih MF, Omar N, Wahab AA
    Clin Nutr ESPEN, 2021 04;42:124-131.
    PMID: 33745565 DOI: 10.1016/j.clnesp.2021.02.005
    BACKGROUND & AIMS: Previous studies have shown that end-tidal carbon dioxide (EtCO2) is lower with the presence of supraphysiological ketones as in the case of chronic ketogenic diet (KD) and diabetic ketoacidosis (DKA). This study aimed to determine changes in EtCO2 upon short term KD.

    METHODS: Healthy subjects were screened not to have conditions that exerts abnormal EtCO2 nor contraindicated for KD. Subjects underwent seven days of KD while the EtCO2 and blood ketone (beta-hydroxybutyrate; β-OHB) parameters were sampled at day zero (t0) and seven (t7) of ketosis respectively. Statistically, the t-test and Pearson's coefficient were conducted to determine the changes and correlation of both parameters.

    RESULTS: 12 subjects completed the study. The mean score ± standard deviation (SD) for EtCO2 were 35.08 ± 3.53 and 35.67 ± 3.31 mm Hg for t0 and t7 respectively. The mean score ±SD for β-OHB were 0.07 ± 0.08 and 0.87 ± 0.84 mmol/L for t0 and t7 respectively. There was no significant difference of EtCO2 between the period of study (p > 0.05) but the β-OHB increased during t7 (p 

    Matched MeSH terms: Carbon Dioxide
  12. Fulltext Effect of modified atmosphere packaging on microbial flora changes in fishery products
    Velu, S., Abu Bakar, F., Mahyudin, N.A., Saari, N., Zaman, M.Z.
    International Food Research Journal, 2013;20(1):17-26.
    MyJurnal
    Modified atmosphere packaging (MAP) has become a popular method for packaging foods as it can extend the shelf life of food with minimal quality defect. Oxygen, nitrogen and carbon dioxide are the common gases used in MAP, Oxygen and carbon dioxide inclusive as only these two gaseous have the preservative effects on the packed food product. Their effect on microbial changes of any food product throughout storage period is highly depend on type of the product and packaging materials, appropriate gas composition, storage temperature, the ratio between gas and product volume, and hygienic manner during processing and packaging. MAP with highest percentage of carbon dioxide is proven to be more effective than vacuum packaging in inhibiting the growth of spoilage and pathogenic bacteria in many fishery products. This article reviews the consequences of MAP towards microbial changes in fishery products.
    Matched MeSH terms: Carbon Dioxide
  13. The effect of flow rate at different pressures and temperatures on cocoa butter extracted from cocoa nib using supercritical carbon dioxide
    Asep EK, Jinap S, Russly AR, Jahurul MH, Ghafoor K, Zaidul IS
    J Food Sci Technol, 2016 May;53(5):2287-97.
    PMID: 27407195 DOI: 10.1007/s13197-016-2191-2
    The effects of flow rate, different pressures and temperatures on cocoa butter extracted from cocoa nib using supercritical carbon dioxide (scCO2) were investigated. The yield was analyzed for total fat content, triacylglycerol (TG) profile, and fatty acid (FA) profile. Extractions were carried out at pressures of 20 and 35 MPa, temperatures of 50 and 60 °C, and CO2 flow rates of 0.5, 1, 2, 4 mL min(-1). The result shows that the yield of cocoa butter extract increased with increasing pressure, temperature, and flow rate and the optimum conditions for the maximum cocoa butter extraction were 35 MPa, 60 °C and 2 mL min(-1), repectively. TGs and FAs were found to be similar in composition to those of cocoa butter obtained by conventional methods. The lower molecular weight TGs and FAs showed higher selectivity compared to higher molecular weight TGs and FAs.
    Matched MeSH terms: Carbon Dioxide
  14. Fulltext Development and validation of a mathematical model for ventilation rate in crop protection structures
    Al-Shamiry, Faisal Mohammed Seif, Desa Ahmad
    Pertanika Journal of Science & Technology, 2010;18(1):-.
    MyJurnal
    Natural ventilation is defined as the number of air exchanges per hour per unit floor area necessary
    to reduce high indoor air temperature and humidity. In addition, it maintains the concentration of carbon dioxide. Natural ventilation is preferred in mechanical system as the ventilation opening is built into the greenhouse, with lower construction cost and no energy and maintenance inputs are required. A mathematical model to quantify natural ventilation rates was developed and verified in large-scale greenhouse structures. For this purpose, four Naturally Ventilated Tropical Greenhouse Structures were designed and constructed at the Malaysian Agricultural Research and Development Institute (MARDI). These were single, double, triple, and quadruple span structures with floor areas of 500 m2, 1000 m2, 1500 m2 and 2000 m2, respectively. This paper presents the validation of a mathematical model which was developed to quantify natural ventilation rates which are very crucial to reduce high in-house temperature built up in the tropics. Regression equations of natural ventilation against wind speed were found to be Φw = 0.0632V, Φw= 0.0395V, Φw= 0.0316Vand Φw=0.0276V for the single, double, triple and quadruple spans, respectively. Meanwhile, coefficients of determination showed strong relationships between ventilation rate and wind speed, with R2 = 0.9999 for all structures. Larger floor area was found to have higher in-house temperature than smaller ones. Ventilation rate inside the single-span structure was found to be higher compared to the multi-span structures, which increased linearly with the increasing wind speed at the eaves of structure.
    Matched MeSH terms: Carbon Dioxide
  15. Single chamber microbial fuel cell (SCMFC) with a cathodic microalgal biofilm: A preliminary assessment of the generation of bioelectricity and biodegradation of real dye textile wastewater
    Logroño W, Pérez M, Urquizo G, Kadier A, Echeverría M, Recalde C, et al.
    Chemosphere, 2017 Mar 01;176:378-388.
    PMID: 28278426 DOI: 10.1016/j.chemosphere.2017.02.099
    An air exposed single-chamber microbial fuel cell (SCMFC) using microalgal biocathodes was designed. The reactors were tested for the simultaneous biodegradation of real dye textile wastewater (RTW) and the generation of bioelectricity. The results of digital image processing revealed a maximum coverage area on the biocathodes by microalgal cells of 42%. The atmospheric and diffused CO2 could enable good algal growth and its immobilized operation on the cathode electrode. The biocathode-SCMFCs outperformed an open circuit voltage (OCV), which was 18%-43% higher than the control. Furthermore, the maximum volumetric power density achieved was 123.2 ± 27.5 mW m(-3). The system was suitable for the treatment of RTW and the removal/decrease of COD, colour and heavy metals. High removal efficiencies were observed in the SCMFCs for Zn (98%) and COD (92-98%), but the removal efficiencies were considerably lower for Cr (54-80%). We observed that this single chamber MFC simplifies a double chamber system. The bioelectrochemical performance was relatively low, but the treatment capacity of the system seems encouraging in contrast to previous studies. A proof-of-concept experiment demonstrated that the microalgal biocathode could operate in air exposed conditions, seems to be a promising alternative to a Pt cathode and is an efficient and cost-effective approach to improve the performance of single chamber MFCs.
    Matched MeSH terms: Carbon Dioxide
  16. Fulltext Production of carbon dioxide using direct pyrolysis-combustion from Aquilariella Malaccensis or karas woods under argon atmosphere
    Noraishah Othman, Siti Kartom Kamarudin, Muhd Noor Md Yunus, Abd. Halim Shamsuddin, Siti Rozaimah, Zahirah Yaakob
    Pertanika Journal of Science & Technology, 2009;17(2):-.
    MyJurnal
    The production of carbon dioxide from Karas woods under argon atmosphere was investigated using a direct pyrolysis-combustion approach. Direct burning was used in this study, using argon for yrolysis and oxygen during combustion to look at the yield of carbon dioxide, produced at different parameters, such as the temperature, retention time and flow rate of argon, as the carrier gas. In this study, a new methodology, 23 response surface central composite design was successfully employed for the experimental design and analysis of results. Central composite experimental design and response surface method were utilized to determine the best operating condition for a maximum carbon dioxide production. Appropriate predictable empirical linear model was developed by incorporating interaction effects of all the variables involved. The results of the analysis revealed that linear equation models fitted well with the experimental for carbon dioxide yield. Nevertheless, the R-Squared obtained using the direct pyrolysis-combustion was 0.7118, indicating that the regression line was not at the best-fitted line.
    Matched MeSH terms: Carbon Dioxide
  17. Fulltext A thermodynamic equilibrium analysis on oxidation of methane to higher hydrocarbons
    Nor Aishah Saidina Amin, Soon, Ee Peng
    Pertanika Journal of Science & Technology, 2009;17(2):-.
    MyJurnal
    Thermodynamic chemical equilibrium analysis using, total Gibbs energy minimization method, was carried out for methane oxidation to higher hydrocarbons. For a large methane conversion and a high selectivity to higher hydrocarbons, the system temperature and oxygen concentration played a vital role, whereas, the system pressure only slightly influenced the two variables. Numerical results showed that the conversion of methane increased with the concentration of oxygen and reaction temperature, but it decreased with pressure. Nevertheless, the presence of oxygen suppressed the formation of higher hydrocarbons which mostly consisted of aromatics, but enhanced the formation of hydrogen. As the system pressure increased, the aromatics, olefins and hydrogen yields diminished, but the paraffin yield improved. Carbon monoxide seemed to be the major oxygen-containing equilibrium product from methane oxidation, whilst almost no H2O, CH3OH and HCOH were detected although traces amount of carbon dioxide were formed at relatively lower temperature and higher pressure. The total Gibbs energy minimization method is useful to theoretically analyze the feasibility of methane conversion to higher hydrocarbons and syngas at the selected temperature and pressure.
    Matched MeSH terms: Carbon Dioxide
  18. Fulltext Modelling of carbon dioxide absorption into aqueous ammonia solution in a wetted wall column
    Ujjal Kumar Ghosh, Chiu, Choon Hong, Jobrun Nandong, Shufeng, Shen
    Pertanika Journal of Science & Technology, 2015;23(1):89-104.
    MyJurnal
    In this paper, a mathematical model is developed based on mass and momentum balance for carbon dioxide absorption into aqueous ammonia solution. The model is simplified based on the assumption that the CO2 absorption into aqueous ammonia is a pseudo-first-order reaction. Laplace transform method is applied in order to solve the partial differential model equation. Finally, the CO2 molar flux is expressed as a function of partial pressure of CO2, concentration of aqueous ammonia, temperature and gas-liquid contact area. Variation of CO2 molar flux with partial pressure of CO2 and temperature is discussed and a comparison is performed with experimental data from literature. Variation of CO2 molar flux is also shown with gas-liquid contact area. The calculated flux from the model follows the same trend as that of the experimental data reported in literature and the accuracy is within the accepted limit. The mathematical model is very helpful to predict the CO2 molar flux as a function of partial pressure of CO2, concentration of aqueous ammonia, temperature and gas-liquid contact area.
    Matched MeSH terms: Carbon Dioxide
  19. Fulltext Effects of process parameters on the production of carbon dioxide from karas woods for radiocarbon dating application using integrated pyrolysis-combustion
    Noraishah Othman, Muhd Noor Md Yunus, Siti Kartom Kamarudin, Abd Halim Shamsuddin, Siti Rozaimah, Zahirah Yaakob
    Journal of Nuclear and Related Technologies, 2008;2008(1):53-63.
    MyJurnal
    Production of carbon dioxide from degraded woods especially Karas or Aquilariella Malaccensis using integrated pyrolysis-combustion is important for radiocarbon dating application. The effects of pyrolysis temperatures (300-400 0 C), retention times (20-35 minutes) and flow rates of argon (400- 1000 ml/min) on the production of carbon dioxide were studied. The experiments were arranged according to a 2 3 response surface central composite statistical design (CSD). This response surface methodology (RSM) was used to assess factor interactions and empirical models regarding carbon dioxide yield. The optimized yield of carbon dioxide was 82.57% for Karas and the optimum reaction conditions are 300 0 C of pyrolysis temperature, 20 minutes retention time and 982ml/min flow rates of argon. Scanning electron microscope (SEM) and X-ray Diffraction (XRD) were conducted to assess the morphological characteristics of the woods and to look at the potential crystalline structure produced after the process took place, respectively.
    Matched MeSH terms: Carbon Dioxide
  20. Fulltext Field evaluation of the efficacy of the mosquito killing system
    O. Wan-Norafikah, CoRe , H. W., Azahari, A. H., K. Kamal-Hidayat, Lee , H. L., I. Saleh
    Jurnal Sains Kesihatan Malaysia, 2017;15(2):9-18.
    MyJurnal
    A preliminary field study was undertaken to evaluate the efficacy of a mosquito trap; Mosquito Killing System (MKS) in
    capturing mosquitoes and other insects. MKS has an automatic activation by the use of a photocell. It is also supplemented
    with carbon dioxide and heat as attractants for mosquitoes and other insects. Three units of MKS were employed at three
    different locations within two study sites for ten days. The mosquitoes and other insects that were trapped in MKS were
    collected and morphologically identified daily in the laboratory. A total of 1,928 mosquitoes and other insects were
    trapped in all units of MKS. High numbers of mosquitoes (93.05%), particularly Aedes sp. and Culex sp. were captured
    from MKS. Among these, Culex quinquefasciatus (91.81%) was most abundant species collected. Only 0.84% of Aedes
    aegypti and Aedes albopictus trapped in MKS. Female mosquitoes (83.44%) were found to be more attracted to MKS
    compared to male mosquitoes of various species. These findings illustrated the potency of MKS utilization in surveillance
    and control activities of Cx. quinquefasciatus; a nuisance mosquito and also potential vector of urban brancroftian
    filariasis in Malaysia.
    Matched MeSH terms: Carbon Dioxide
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