Displaying publications 21 - 40 of 76 in total

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  1. Effect of monoethanolamine loading on the physicochemical properties of amine-functionalized Si-MCM-41
    Anita Ramli, Sohail Ahmed, Suzana Yusup
    Sains Malaysiana, 2014;43:253-259.
    Siliceous mesoporous molecular sieve (Si-MCM-41) material with highly ordered hexagonal pore arrangement was synthesized at 373 K for 8-days duration by hydrothermal method, dried at 393 K and calcined at 823 K in N2 atmosphere. The calcined Si-MCM-41 was later functionalized with 10-50 wt. % monoethanolamine (MEA) by impregnation method and dried in vacuum at 343 K. The MEA-Si-MCM-41 samples were characterized for their physicochemical properties with FTIR, XRD, TGA, HRTEM, FESEM, BET and elemental analysis. XRD results showed that the intensity of the characteristic peaks of Si-MCM-41 reduces with increasing loading of MEA indicating that the MEA molecules are loaded in the pores as well as on the surface of Si-MCM-41. The appearance of FTIR peaks corresponding to N-H, C-N and C-H bonds suggested that Si-MCM-41 has been functionalized with MEA. The presence of Si-O-Si peaks in FTIR spectra of MEA-Si-MCM-41 samples indicates that the hexagonal pore arrangement remains intact and this is supported by HRTEM images. FESEM images show that MEA-Si-MCM-41 samples became agglomerated with increase loading of MEA. TGA analyses show that the MEA-Si-MCM-41 samples are thermally stable up to 528 K. N2 adsorption-desorption isotherms show that the textural properties of Si-MCM-41 material slowly change from a mesoporous material to non-porous material as the MEA loading increases due to pore filling effect during functionalization with MEA. Detection of N, C and H by elemental analysis confirms the presence of MEA in MEA-Si-MCM-41 samples.
    Matched MeSH terms: Atmosphere
  2. Life cycle inventory of institutional medium-scaled co-composting of food waste and yard waste in tropical country
    Chee Guan Ng, Sumiani Yusoff
    Sains Malaysiana, 2015;44:517-527.
    The main objective of the present study was to provide a comprehensive LCI of medium scale composting of food waste
    and yard waste at institutional level, based on substance flow analysis (SFA). A secondary objective was to present the
    composition and assess the quality of the final compost product from composting of typical Asian organic waste (food
    waste and yard waste). The experiments were designed to represent a batch situation in an institutional medium size
    composting scenario with input material of food waste mixed with grass clippings and dried leaves. Two composting
    runs were carried out with the intention to showcase the heterogeneity of organic waste and study the effect of windrow
    size on the performance of the process. The input and output material were sampled and characterized in order to
    quantify the substance balance of the process. SFA was performed by means of the mass balance model STAN 2.5 to
    compute unknown parameters (gaseous emissions). SFAs have been performed for C, N, K, P, Cd, Cr, Cu, Ni and Pb. The
    composting windrows were fed with 212.4 and 393 kg, respectively. VS content reduction is greater in composting pile
    with larger size (Run 2). The loss of C during composting was recorded in the range of 0.146-0.166 kg/kg ww. The C
    losses via leachate were insignificant (0.02% of the total input C). The total N loss during the process was 0.005-0.012
    kg/kg ww. The leachate generation was measured as 0.012-0.013 kg/kg ww. The flows of selected heavy metals were
    assessed. Heavy metals were of minor significance due to low concentrations in the inputs (food waste and yard waste).
    Heavy metals were found to be released to the atmosphere. However, majority of heavy metals remain in the finished
    compost. The C/N reduction during the process was in the range of 10-23%. In general, the compost composition was
    considered to be within the ranges previously reported in literature and thus ready for application in gardening. The LCI
    presented in the present study can be used as a starting point for making environmental assessments of medium-scale
    co-composting of food waste and yard waste in tropical environment. No major environmental problems were identified
    from the process, except for the emissions of GHGs.
    Matched MeSH terms: Atmosphere
  3. Colourimetric determination of features of an air sampling technique optimal for detection of surfactants
    Nur Hazimah Abdul Halim, Norfazrin Mohd Hanif, Mohamed Rozali Othman, Mohd Talib Latif
    Sains Malaysiana, 2010;39:175-179.
    Surfactants in the atmosphere may act as cloud condensation nuclei, with a potentially negative impact on the global climate. Therefore, accurate determination of surfactants is crucial in order to investigate the possible effects of surfactants on the atmosphere. The aim of this study was to identify the optimum sampling method for measuring the maximum quantity of surfactants present in ambient air. Air samples were collected using a range of air sampling pumps that were made to vary in terms of flow rate, storage period, type of absorbing solution and the characteristics of the impinger tube. Samples obtained were analysed by colourimetry for anionic and cationic surfactants as methylene blue-active substances (MBAS) and disulphine blue-active substances (DBAS), respectively. Absorbance was measured at 650 nm for MBAS and 628 nm for DBAS using UV-visible spectrophotometer. We found that the optimum sampling method consisted of an absorbent solution (deionised water, buffer solution and methylene blue/disulphine blue solution) with the flow rate of 1.0 L/min. The concentration of surfactants in all sampling methods remained constant regardless of the storage period (1 day and 4 days), indicating that surfactants in the absorbing solution are quite stable. Covering the impinger tube was shown to influence the amount of both anionic and cationic surfactants detected.
    Matched MeSH terms: Atmosphere
  4. Fulltext Study domain and its influences on family-work enrichment among Teachers
    Safaril, Maadon, Zaiton, Hassan, Mark, Kasa, Ida Juliana, Hutasuhut
    Journal of Cognitive Sciences & Human Development, 2019;5(1):19-28.
    MyJurnal
    Work-Life balance (WLB) studies have investigated heavily on family domain even though
    there are sub domains in life. Thus, this study will contribute to the literature by examining
    study domain (lifelong learning and organizational learning) and its influence on familywork
    enrichment (FWE) among teachers who are currently continuing their education in
    Lundu district. A total of 117 teachers responded to the self-administered questionnaire. The
    finding revealed that both organizational learning and lifelong learning have a positive significant
    relationship with family work enrichment. Therefore, school management should
    encourage the culture of lifelong learning and at the same time provide facilities and atmosphere
    to support the culture will ensure family-work enrichment among teachers who are
    continuing their study.
    Matched MeSH terms: Atmosphere
  5. Rainwater chemistry of acid precipitation occurrences due to long-range transboundary haze pollution and prolonged drought events during southwest monsoon season: climate change driven
    Payus CM, Jikilim C, Sentian J
    Heliyon, 2020 Sep;6(9):e04997.
    PMID: 33005801 DOI: 10.1016/j.heliyon.2020.e04997
    The purposes of this research were to study the characteristics chemistry of pH, anions and cations in rainwater, and to identify the possible sources that contributing to the acid precipitation during southwest monsoon season with occurrence of extreme drought event. During the southwest monsoon season, it normally occurs along with haze phenomenon that every year will hit Southeast Asia. This condition will aggravate with high acidic particles in the atmosphere due to the prolonged drought. The analysed parameters which involved pH, anions (NO3-, SO42- and Cl-) and cations (Ca2+, Mg2+, Na+ and K+) were analysed using pH meter, Hach DR 2800, argentometric method and ICP-OES. From the findings, it showed that acid rain occurred during the southwest monsoon season with the range of pH values from 4.95 ± 0.13 to 6.40 ± 0.03 and the total average of pH 5.71 ± 0.32. Anions NO3-, SO42- and Cl- were found to be the dominant compositions of the acid rain occurrences with higher concentrations detected. In overall, rural area recorded with higher acidity of precipitation at total average of pH 5.54 ± 0.39 compared to urban area at pH 5.77 ± 0.26. Rural area surprisingly recorded higher frequency occurrences of acid rain with pH lesser than 5.6 and below compared to urban area. As for public health and safety, all rainwater samples during the acid rain event were found exceeded the allowable limits of NWQS and WHO standards, that shown not suitable for skin contact, recreational purposes even for drinking purposes.
    Matched MeSH terms: Atmosphere
  6. Fulltext C mobilisation in disturbed tropical peat swamps: old DOC can fuel the fluvial efflux of old carbon dioxide, but site recovery can occur
    Waldron S, Vihermaa L, Evers S, Garnett MH, Newton J, Henderson ACG
    Sci Rep, 2019 08 07;9(1):11429.
    PMID: 31391485 DOI: 10.1038/s41598-019-46534-9
    Southeast-Asian peat swamp forests have been significantly logged and converted to plantation. Recently, to mitigate land degradation and C losses, some areas have been left to regenerate. Understanding how such complex land use change affects greenhouse gas emissions is essential for modelling climate feedbacks and supporting land management decisions. We carried out field research in a Malaysian swamp forest and an oil palm plantation to understand how clear-felling, drainage, and illegal and authorized conversion to oil palm impacted the C cycle, and how the C cycle may change if such logging and conversion stopped. We found that both the swamp forest and the plantation emit centuries-old CO2 from their drainage systems in the managed areas, releasing sequestered C to the atmosphere. Oil palm plantations are an iconic symbol of tropical peatland degradation, but CO2 efflux from the recently-burnt, cleared swamp forest was as old as from the oil palm plantation. However, in the swamp forest site, where logging had ceased approximately 30 years ago, the age of the CO2 efflux was modern, indicating recovery of the system can occur. 14C dating of the C pool acted as a tracer of recovery as well as degradation and offers a new tool to assess efficacy of restoration management. Methane was present in many sites, and in higher concentrations in slow-flowing anoxic systems as degassing mechanisms are not strong. Methane loading in freshwaters is rarely considered, but this may be an important C pool in restored drainage channels and should be considered in C budgets and losses.
    Matched MeSH terms: Atmosphere
  7. Fulltext The FLUXNET2015 dataset and the ONEFlux processing pipeline for eddy covariance data
    Pastorello G, Trotta C, Canfora E, Chu H, Christianson D, Cheah YW, et al.
    Sci Data, 2020 07 09;7(1):225.
    PMID: 32647314 DOI: 10.1038/s41597-020-0534-3
    The FLUXNET2015 dataset provides ecosystem-scale data on CO2, water, and energy exchange between the biosphere and the atmosphere, and other meteorological and biological measurements, from 212 sites around the globe (over 1500 site-years, up to and including year 2014). These sites, independently managed and operated, voluntarily contributed their data to create global datasets. Data were quality controlled and processed using uniform methods, to improve consistency and intercomparability across sites. The dataset is already being used in a number of applications, including ecophysiology studies, remote sensing studies, and development of ecosystem and Earth system models. FLUXNET2015 includes derived-data products, such as gap-filled time series, ecosystem respiration and photosynthetic uptake estimates, estimation of uncertainties, and metadata about the measurements, presented for the first time in this paper. In addition, 206 of these sites are for the first time distributed under a Creative Commons (CC-BY 4.0) license. This paper details this enhanced dataset and the processing methods, now made available as open-source codes, making the dataset more accessible, transparent, and reproducible.
    Matched MeSH terms: Atmosphere
  8. Co-valorization of delayed petroleum coke - palm kernel shell for activated carbon production
    Rashidi NA, Yusup S
    J Hazard Mater, 2021 02 05;403:123876.
    PMID: 33264948 DOI: 10.1016/j.jhazmat.2020.123876
    In this study, a binary mixture of petroleum coke and palm kernel shell had been investigated as potential starting materials for activated carbon production. Single-stage potassium carbonate (K2CO3) activation under nitrogen (N2) atmosphere was adopted in this research study. Effect of several operating parameters that included the impregnation ratio (1-3 wt./wt.), activation temperature (600-800 °C), and dwell time (1-2 hrs) were analyzed by using the Box-Behnken experimental design. Influence of these parameters towards activated carbon yield (Y1) and carbon dioxide (CO2) adsorption capacity at an atmospheric condition (Y2) were investigated. The optimum conditions for the activated carbon production were attained at impregnation ratio of 1.75:1, activation temperature of 680 °C, and dwell time of 1 h, with its corresponding Y1 and Y2 is 56.2 wt.% and 2.3991 mmol/g, respectively. Physicochemical properties of the pristine materials and synthesized activated carbon at the optimum conditions were analyzed in terms of their decomposition behavior, surface morphology, elemental composition, and textural characteristics. The study revealed that the blend of petroleum coke and palm kernel shell can be effectively used as the activated carbon precursors, and the experimental findings demonstrated comparable CO2 adsorption performance with commercial activated carbon as well as that in literatures.
    Matched MeSH terms: Atmosphere
  9. Effect of irradiance on the emission of short-lived halocarbons from three common tropical marine microalgae
    Lim YK, Keng FS, Phang SM, Sturges WT, Malin G, Abd Rahman N
    PeerJ, 2019;7:e6758.
    PMID: 31041152 DOI: 10.7717/peerj.6758
    Marine algae have been reported as important sources of biogenic volatile halocarbons that are emitted into the atmosphere. These compounds are linked to destruction of the ozone layer, thus contributing to climate change. There may be mutual interactions between the halocarbon emission and the environment. In this study, the effect of irradiance on the emission of halocarbons from selected microalgae was investigated. Using controlled laboratory experiments, three tropical marine microalgae cultures, Synechococcus sp. UMACC 371 (cyanophyte), Parachlorella sp. UMACC 245 (chlorophyte) and Amphora sp. UMACC 370 (diatom) were exposed to irradiance of 0, 40 and 120 µmol photons m-2s-1. Stress in the microalgal cultures was indicated by the photosynthetic performance (Fv/Fm, maximum quantum yield). An increase in halocarbon emissions was observed at 120 µmol photons m-2s-1, together with a decrease in Fv/Fm. This was most evident in the release of CH3I by Amphora sp. Synechococcus sp. was observed to be the most affected by irradiance as shown by the increase in emissions of most halocarbons except for CHBr3 and CHBr2Cl. High positive correlation between Fv/Fm and halocarbon emission rates was observed in Synechococcus sp. for CH2Br2. No clear trends in correlation could be observed for the other halocarbons in the other two microalgal species. This suggests that other mechanisms like mitochondria respiration may contribute to halocarbon production, in addition to photosynthetic performance.
    Matched MeSH terms: Atmosphere
  10. Fulltext Design, synthesis and biological profile of heterocyclic benzimidazole analogues as prospective antimicrobial and antiproliferative agents
    Tahlan S, Kumar S, Ramasamy K, Lim SM, Shah SAA, Mani V, et al.
    BMC Chem, 2019 Dec;13(1):50.
    PMID: 31384798 DOI: 10.1186/s13065-019-0567-x
    Background: Nitrogen containing heterocycles are widely used and investigated by pharmaceutical industry, as they are important in discovery and designing of new drug molecules. Drugs with a benzimidazole nucleus possess exclusive structural features and electron-rich atmosphere, which enable them to bind to a number of biologically important targets and result in a wide range of activities. This has served as the basis of the present study whereby new scaffolds with benzimidazole moiety were designed and synthesized.

    Methods: The structures of synthesized compounds were confirmed by physicochemical and spectral means. The synthesized compounds were screened for their antimicrobial and antiproliferative activities by tube dilution and Sulforhodamine B (SRB) assays, respectively.

    Results and conclusion: The in vitro biological screening results revealed that compound Z24 exhibited promising antimicrobial and anticancer activities which are comparable to standards.

    Matched MeSH terms: Atmosphere
  11. Efficient transport of atmospheric microplastics onto the continent via the East Asian summer monsoon
    Wang X, Liu K, Zhu L, Li C, Song Z, Li D
    J Hazard Mater, 2021 07 15;414:125477.
    PMID: 33647626 DOI: 10.1016/j.jhazmat.2021.125477
    The presence of microplastics (MPs) in the atmosphere is a global concern because of its environmental and health impacts; however, the monsoonal transport of atmospheric MPs has not yet been investigated. To fully understand the effect of the monsoon on atmospheric MP transport, we conducted a study along the southeast coast of China during the East Asian summer monsoon (EASM). We found that the EASM transports atmospheric MPs back onto the continent at a flux of up to 212.977-213.433 kg/EASM/year. The backward trajectory and wind field results indicate that the EASM provides an effective MP transport pathway from Vietnam, the Philippines, and Malaysia to southeastern China. This suggests that only some of the airborne MPs over the ocean enter the marine ecosystem. The average abundance of atmospheric MPs over the sampling area was 0.39 items/100 m3 (0.39 ± 0.43 items/100 m3) during the EASM season, with high variability among the sampling sites. This study improves our understanding of the impact of the EASM on atmospheric MP transport, which can help quantify the contributions of atmospheric MPs to marine or terrestrial ecosystems.
    Matched MeSH terms: Atmosphere
  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: Atmosphere
  13. Fulltext Physico-chemical changes in dabai (Canarium odontophyllum Miq.) fruit during modified atmosphere storage
    Ding, P., Diana, J.
    International Food Research Journal, 2013;20(6):3033-3040.
    MyJurnal
    Dabai or Canarium odontophyllum Miq., from the family Burseraceae, is an important indigenous fruit to Borneo Island. However, it is a highly perishable fruit with short shelf life. Postharvest technology such as modified atmosphere packaging (MAP) can be used to maintain highly perishable fresh fruit quality and increase its shelf life. There is not much work has been carried out to study effect of MAP on dabai fruit. Therefore, this study was conducted to determine the effect of four different types packaging methods on the postharvest quality of dabai fruits. Total of 240 fruit were used for each replication and the experiment was repeated thrice. Fruit were divided equally into four groups with each group packed in low-density polyethylene plastic bag, low-density polyethylene plastic bags lined with tissue paper, low-density polyethylene plastic bag with vacuumed and control (unwrapped). The fruit were then stored in a cold room of 10°C for 8 days. The fruits were analyzed for peel and flesh colour (L*, C* and hue angle), CO2 and C2H4 production, weight loss, firmness, soluble solids concentration (SSC), titratable acidity (TA) and pH at every two days interval. Data were analyzed using analysis of variance and means was separated using Duncan’s multiple range tests. The use of MAP retained peel colour (L*, C* and hue angle values), flesh colour (L*values), SSC and TA of dabai fruit. The CO2 production in MAP fruit was significant lower than control. Although vacuum packed showed lowest weight loss, flesh discolouration, soggy texture and foul sour odour developed during 8 days of storage. Neither packing dabai fruit in low-density polyethylene plastic bag nor bag lined with tissue paper retained better fruit quality. Thus, it is recommended packing dabai fruit in low-density polyethylene plastic bag is sufficient to retain fruit quality during 8 days of storage at 10oC.
    Matched MeSH terms: Atmosphere
  14. Fulltext Effects of different levels of CO2 on biochemical changes and relationships among different quality indices in Indian mackerel (Rastrelliger kanagurta)
    Chong, C.Y., Fatimah, A.B., Russly, A.R., Jamilah, B., Selvi, V., Maryam, S.
    International Food Research Journal, 2013;20(1):383-389.
    MyJurnal
    The profile of total volatile base nitrogen (TVBN), pH, biogenic amines were studied in Indian mackerel packed under different levels of CO2. Gutted and beheaded Indian mackerel was stored in air, vacuum packaging (VP), 30% CO2/65% N2/5% O2 (M30C), 60% CO2/35%N2/5%O2 (M60C), 80% CO2/15%N2/5% O2 (M80C) and 100% CO2 (M100C) at 5°C for 12 days. The application of VP and MAP was effective in retarding the formation of TVBN, total biogenic amines and improve the shelf life of Indian mackerel. Cadaverine obtained the best correlation with storage time when compared with other biogenic amines. Cadaverine or cadaverine + putrescine can serve as a reliable objective freshness indicator of fish stored in different atmospheres. Among the commonly used freshness indices, TVBN was the best quality indicator correlated with histamine. VP and MAP conditions influenced the performance of quality indicators. pH was a good quality indicator of spoilage in air-stored fish except for VP and MAP packed fish. Lower value of TVBN (30 mg/100g) was suggested as an upper limit for this species of fish under MAP condition based on APC and sensory result.
    Matched MeSH terms: Atmosphere
  15. Effects of reaction conditions on the emission behaviors of arsenic, cadmium and lead during sewage sludge pyrolysis
    Han H, Hu S, Syed-Hassan SSA, Xiao Y, Wang Y, Xu J, et al.
    Bioresour Technol, 2017 Jul;236:138-145.
    PMID: 28399417 DOI: 10.1016/j.biortech.2017.03.112
    Sewage sludge is an important class of bioresources whose energy content could be exploited using pyrolysis technology. However, some harmful trace elements in sewage sludge can escape easily to the gas phase during pyrolysis, increasing the potential of carcinogenic material emissions to the atmosphere. This study investigates emission characteristics of arsenic, cadmium and lead under different pyrolysis conditions for three different sewage sludge samples. The increased temperature (within 723-1123K) significantly promoted the cadmium and lead emissions, but its influence on arsenic emission was not pronounced. The releasing rate order of the three trace elements is volatile arsenic compounds>cadmium>lead in the beginning of pyrolysis. Fast heating rates promoted the emission of trace elements for the sludge containing the highest amount of ash, but exhibited an opposite effect for other studied samples. Overall, the high ash sludge released the least trace elements almost under all reaction conditions.
    Matched MeSH terms: Atmosphere
  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: Atmosphere
  17. Fulltext An overview of mercury emission sources and application of activated carbon for mercury removal from flue gas
    Hidayu Abdul Rani, Nor Fadilah Mohamad, Sherif Abdulbari Ali, Matali, Sharmeela, Sharifah Aishah Sheikh Abdul kadir
    Scientific Research Journal, 2013;10(1):0-0.
    MyJurnal
    Mercury emission into the atmosphere is a global concern due to its detrimental effects on human health in general. The two main sources of mercury emission are natural sources and anthropogenic sources. Mercury emission from natural sources include volcanic activity, weathering of rocks, water movement and biological processes which are obviously inevitable. The anthropogenic sources of mercury emission are from coal combustion, cement production and waste incineration. Thus, in order to reduce mercury emission it is appropriate to investigate how mercury is released from the anthropogenic sources and consequently the mercury removal technology that can be implemented in order to reduce mercury emission into the atmosphere. Many alternatives have been developed to reduce mercury emission and the recent application of activated carbon showed high potential in the adsorption of elemental mercury. This paper discusses the ability of activated carbon and variable parameters that influence mercury removal efficiency in flue gas.
    Matched MeSH terms: Atmosphere
  18. Fulltext A study of microstructure and hardness on Fe-Co/SiC composites
    Noraziana Parimin, Linus, Andy
    Journal of Nuclear and Related Technologies, 2009;2009(1):65-70.
    MyJurnal
    This research was conducted to study the effect of reinforcement particles on iron-cobalt (FeCo) composites. The composition of silicon carbide (SiC) was varied from 0 to 20 wt%. The composite was fabricated via powder metallurgy (PM) method, which consists of mixing, compaction and sintering processes. The powder was mixed for 2 hours to obtain uniformity between SiC and Fe-Co matrix and compacted to a cylindrical shape at 250 MPa. Samples were sintered for 2 hours at 900 o C with 10 o C/minute heating rate in argon atmosphere. The influences of reinforcement particle on the sintered samples were characterized in terms of microstructure and hardness testing. The Fe-Co/20wt%SiC composites show highest hardness value.
    Matched MeSH terms: Atmosphere
  19. Utilization of Malaysia EAF slags for effective application in direct aqueous sequestration of carbon dioxide under ambient temperature
    Omale SO, Choong TSY, Abdullah LC, Siajam SI, Yip MW
    Heliyon, 2019 Oct;5(10):e02602.
    PMID: 31667417 DOI: 10.1016/j.heliyon.2019.e02602
    Iron and steel industries are among the contributors of CO2 emission in large volume into the atmosphere, causing detrimental effects to the environment and the ecosystem at large scale. These industries also generate solid wastes in the form of electric arc furnace (EAF) slag during operations which result in about 10-15% slag wastes per ton of steel produced. In this study, the EAF slags from an iron and steel-making factory in Klang, Malaysia was utilized for CO2 sequestration through direct aqueous mineral carbonation. According to the surface area analysis, the fresh EAF slag has a mesoporous structure, its elemental composition shows the presence of 20.91 wt.% of CaO that was used for the sequestration of CO2 through carbonation. The sequestration capacity was found to be 58.36 g CO2/kg of slag at ambient temperature in 3 h, with the liquid/solid (L/S) ratio of 5:1 and using <63μm particle size. Moreover, the shrinking core model (SCM) was used to analyze the solid-fluid reaction in a heterogeneous phase and the CO2 sequestration shows to be controlled by the product layer phase. The EAF slag is demonstrated to have the potential of CO2 sequestration at ambient temperature.
    Matched MeSH terms: Atmosphere
  20. Effects of debinding and sintering atmosphere on properties and corrosion resistance of powder injection molded 316 L - stainless steel
    Raza MR, Sherazi I, Muhammad Aslam, Ahmad F, Abu Bakar Sulong, Muhamad Norhamidi, et al.
    Sains Malaysiana, 2017;46:285-293.
    316L stainless steel is a common biomedical material. Currently, biomedical parts are produced through powder injection molding (PIM). Carbon control is the most critical in PIM. Improper debinding can significantly change the properties of the final product. In this work, thermal debinding and sintering were performed in two different furnaces (i.e. laboratory and commercially available furnaces) to study the mechanical properties and corrosion resistance. Debounded samples were sintered in different atmospheres. The samples sintered in inert gas showed enhanced mechanical properties compared with wrought 316L stainless steel and higher corrosion rate than those sintered in the vacuum furnace. The densification and tensile strength of the hydrogen sintered samples increased up to 3% and 51%, respectively, compared with those of the vacuum-sintered samples. However, the samples sintered in inert gas also exhibited reduced ductility and corrosion resistance. This finding is attributed to the presence of residual carbon in debonded samples during debinding.
    Matched MeSH terms: Atmosphere
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