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  • 1
    Online Resource
    Online Resource
    Profitable Fischer Tropsch realization via CO 2 –CH 4 reforming; an overview of nickel–promoter–support interactions
    Royal Society of Chemistry (RSC) ; 2023
    In:  RSC Advances Vol. 13, No. 3 ( 2023), p. 1711-1726
    Details
    In: RSC Advances, Royal Society of Chemistry (RSC), Vol. 13, No. 3 ( 2023), p. 1711-1726
    Abstract: Environmental pollution, climate change, and fossil fuel extinction have aroused serious global interest in the search for alternative energy sources. The dry reforming of methane (DRM) could be a good technique to harness syngas, a starting material for the FT energy process from greenhouse gases. Noble metal DRM catalysts are effective for the syngas generation but costly. Therefore, they inevitably, must be replaced by their Ni-based contemporaries for economic reasons. However, coking remains a strong challenge that impedes the industrialization of the FT process. This article explains the secondary reactions that lead to the production of detrimental graphitic coke deposition on the surface of active nickel catalyst. The influence of nickel particle size, impact of extra surface oxygen species, interaction of Ni catalysts with metal oxide supports/promoters, and larger fraction of exposed nickel active sites were addressed in this review. Size of active metal determines the conversion, surface area, metal dispersion, surface reactions, interior diffusion effects, activity, and yield. The influence of oxygen vacancy and coke deposition on highly reported metal oxide supports/promoters (Al 2 O 3 , MgO and La 2 O 3 ) was postulated after studying CIFs (crystallographic information files) obtained from the Crystallography open database (COD) on VESTA software. Thus, overcoming excessive coking by La 2 O 3 promotion is strongly advised in light of the orientation of the crystal lattice characteristics and the metal–support interaction can be used to enhance activity and stability in hydrogen reforming systems.
    Type of Medium: Online Resource
    ISSN: 2046-2069
    URL: Article
    DOI: 10.1039/D2RA06773K
    Language: English
    Publisher: Royal Society of Chemistry (RSC)
    Publication Date: 2023
    detail.hit.zdb_id: 2623224-8
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  • 2
    Online Resource
    Online Resource
    Chemical contents and thermal stability of Madu bamboo (Gigantochloa albociliata) for natural-bonded fiber composites
    IOP Publishing ; 2021
    In:  IOP Conference Series: Earth and Environmental Science Vol. 644, No. 1 ( 2021-01-01), p. 012009-
    Details
    In: IOP Conference Series: Earth and Environmental Science, IOP Publishing, Vol. 644, No. 1 ( 2021-01-01), p. 012009-
    Abstract: The objective of this study was to evaluate the chemical contents and thermal stability of young (3 years old or less) and matured (more than 5 years old) Madu Bamboo ( Gigantochloa albociliata ). The comprehensive knowledge of these properties will help to promote the uses of this bamboo’s fiber for natural-bonded composite products. The different age levels of bamboo can be an indicator in evaluating the significant difference of the chemical contents and thermal stability of bamboo. The chemical contents were determined in accordance to the standard outline in Technical Association of Pulp and Paper Industry (TAPPI) test method, while thermal stability was conducted in accordance to Shimadzu TGA 50 analyzer. The culm exhibited different chemical contents between young and old age, in which, young bamboo showed higher hot water extractives and ash contents compared to mature bamboo. On the other hand, matured bamboo contained higher alcohol-toluene extractives, holocellulose, a-cellulose and lignin than young ones. Hence, more resin and possible wood gum in matured bamboo that is beneficially in natural bonded composite product. The thermal analysis of extracted bamboo fiber indicated the thermal degradation behavior of both young and matured bamboo with the same species. The maximum temperature degradation of both young and matured bamboos was 413°C and 404°C. Therefore, matured bamboo was degraded at lower temperature compared to young bamboo, which indicates lower thermal stabilities. The result of this study reported that young bamboo of G. albociliata species is acceptable to be harvested at young ages for reinforcement in natural bonded composite board, according to their thermal stabilities and chemical contents.
    Type of Medium: Online Resource
    ISSN: 1755-1307 , 1755-1315
    URL: Article
    DOI: 10.1088/1755-1315/644/1/012009
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2021
    detail.hit.zdb_id: 2434538-6
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  • 3
    Online Resource
    Online Resource
    Green environment: Effects of acetate buffer on cellulose production by Acetobacter xylinum 0416 in fermented static cultivation
    IOP Publishing ; 2022
    In:  IOP Conference Series: Earth and Environmental Science Vol. 951, No. 1 ( 2022-01-01), p. 012025-
    Details
    In: IOP Conference Series: Earth and Environmental Science, IOP Publishing, Vol. 951, No. 1 ( 2022-01-01), p. 012025-
    Abstract: Bacterial cellulose (BC) white leathery pellicle produced from fermentation process of Acetobacter xylinum has many advantages such as high-water holding capacity, high porosity and high purity compared to plant cellulose. However, one of the BC application problems in industry is its low bio-cellulose productivity. The significant decrease of BC production can be effected by the reduction of pH culture due to production of by-product, gluconic acid during the static fermentation process. Therefore, the production of BC pellicle would be improved efficiently by controlling the pH of BC static cultivation. Bio-cellulose dry weight was at the greatest in acetates of 5.66 g/L while the dry weight derived from BC is 2.72 and 2.56 g/L in Control and Hestrin and Schramm (HS). The acetate buffered medium can be completed in a static fermentation method which can improve BC film production effectively.
    Type of Medium: Online Resource
    ISSN: 1755-1307 , 1755-1315
    URL: Article
    DOI: 10.1088/1755-1315/951/1/012025
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2022
    detail.hit.zdb_id: 2434538-6
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  • 4
    Online Resource
    Online Resource
    Bamboo as future bio-industrial material: Physical behaviour and bending strength of Malaysia’s Beting bamboo (Gigantochloa levis)
    IOP Publishing ; 2022
    In:  IOP Conference Series: Earth and Environmental Science Vol. 951, No. 1 ( 2022-01-01), p. 012001-
    Details
    In: IOP Conference Series: Earth and Environmental Science, IOP Publishing, Vol. 951, No. 1 ( 2022-01-01), p. 012001-
    Abstract: In this paper, bending strength and physical properties (specific gravity, dimensional stability and equilibrium moisture content) of a Malaysian bamboo locally known as Beting bamboo (Gigantochloa levis) are addressed. Characterizations of physical and bending strength of G. levis in terms of the variability of location along culm height (top, middle, bottom), culm section (nodes and internodes), fiber orientation (longitudinal, tangential and radial) and culm layer (outer and inner) were conducted. Comparison of these properties is also made to some bamboo and commercial timber species. It was found that G. levis has favorable physical and mechanical properties although the specific gravity of G. levis has tendency to be on the higher side. The characteristics studied were found to have some variability at different locations, sections, and directions. There was variability in terms of bending strength along with the culm height of bamboo. It is indicated from this study that the bending strength and physical properties of G. levis were found to be satisfactory.
    Type of Medium: Online Resource
    ISSN: 1755-1307 , 1755-1315
    URL: Article
    DOI: 10.1088/1755-1315/951/1/012001
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2022
    detail.hit.zdb_id: 2434538-6
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  • 5
    Online Resource
    Online Resource
    Effects of steam-treatment on the chemical component and thermal resistance of bagasse particle for natural-bonded composites product
    IOP Publishing ; 2021
    In:  IOP Conference Series: Earth and Environmental Science Vol. 922, No. 1 ( 2021-11-01), p. 012012-
    Details
    In: IOP Conference Series: Earth and Environmental Science, IOP Publishing, Vol. 922, No. 1 ( 2021-11-01), p. 012012-
    Abstract: The objective of this study was to evaluate the chemical composition of steam-treated bagasse particle by using autoclave. Fine size particle was obtained from the milling process of steam-treated bagasse. Before testing, the particle was pre-treated for 5, 10 and 15 minutes. The determination of extractives, lignin, α-cellulose, holocellulose and ash-content were conducted in accordance with the standard outline in the Technical Association Pulp and Paper Industry (TAPPI) test methods. Overall results show that the chemical properties have been diminished over time. The chemical properties with the highest percentage of extractive, lignin, ash and holocellulose contents (which was 3.9%, 39.15%, 1.45% and 73% respectively, was extracted at 121°C for 5 minutes). The lowest percentage of extractive, lignin, ash and holocellulose contents (which was 0.8%, 25.30%, 0.88% and 51% respectively, was extracted at 121°C for 15 minutes). It is concluded that longer steam treatment time (beyond 15 minutes) may degrade the chemical properties of bagasse. In addition, thermo-gravimetric analysis (TGA) was also carried out to investigate the thermal resistance of bagasse particle. Based on the results, the 10 minutes steamed samples have the highest peak degradation temperature, which was 286.8 °C, while the 15 minutes steamed samples have the lowest peak degradation, which was 246.4 °C. This shows that longer steaming period (more than 10 minutes) will decrease the thermal resistance of the bagasse particle.
    Type of Medium: Online Resource
    ISSN: 1755-1307 , 1755-1315
    URL: Article
    DOI: 10.1088/1755-1315/922/1/012012
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2021
    detail.hit.zdb_id: 2434538-6
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  • 6
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    Online Resource
    High Density Polyethylene (HDPE) composite mixed with Azadirachta excelsa (Sentang) tree waste flour: Mechanical and physical properties
    IOP Publishing ; 2022
    In:  IOP Conference Series: Earth and Environmental Science Vol. 951, No. 1 ( 2022-01-01), p. 012045-
    Details
    In: IOP Conference Series: Earth and Environmental Science, IOP Publishing, Vol. 951, No. 1 ( 2022-01-01), p. 012045-
    Abstract: This article presents the application of plantation waste materials (leaves, branches and trunks) of Azadirachta excelsa (Sentang) tree in order to evaluate and compare their suitability as reinforcement and filler for high density polyethylene (HDPE) thermoplastics. The aim of the study was to investigate the effect of different types of Azadirachta excelsa (Sentang) trunks flour, branches flour and leaves flour fillers on the mechanical and physical properties of HDPE composite. The composite samples were produced using 25%, 35% and 45% by weight of flour filler loading and 2% coupling agent (maleic anhydride) using a twin-screw extruder, followed by injection molding process. The flexural modulus and tensile strength of the composite filled with trunk flour were not significantly different with the composite-filled branch flour. However, there is a significant difference between composite-filled leaf flour when compared to both composite-filled trunk flour and composite-filled branch flours. Overall, composite samples with trunk flour show better mechanical properties, while composite samples with lower filler loadings of 25% exhibit better dimensional stability compared to the other such as 35% and 45% filler loadings. The study also indicated that composite filled with leaf, branch and trunk flours had better mechanical strength than virgin HDPE.
    Type of Medium: Online Resource
    ISSN: 1755-1307 , 1755-1315
    URL: Article
    DOI: 10.1088/1755-1315/951/1/012045
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2022
    detail.hit.zdb_id: 2434538-6
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  • 7
    Online Resource
    Online Resource
    Investigation on the nonlinear dynamic response of a mass-spring system
    IOP Publishing ; 2020
    In:  IOP Conference Series: Materials Science and Engineering Vol. 788, No. 1 ( 2020-04-01), p. 012085-
    Details
    In: IOP Conference Series: Materials Science and Engineering, IOP Publishing, Vol. 788, No. 1 ( 2020-04-01), p. 012085-
    Abstract: This paper investigates the nonlinear dynamic response of a single-degree-of-freedom mass-spring system. The experimental modal analysis is carried out by three typical types of spectral testing which are burst random, sine testing and periodic chirp excitation to achieve the objective of this study. The experimental data from the burst random excitation is used to identify the natural frequency of the system. The nonlinear dynamic response of the system is detected by means of using the sine testing and periodic chirp excitation. However, from the sine testing, the results showed that the variations of the maximum peak of the vibration acceleration based on the different levels of excitation voltage that were applied to the input shaker. It was also found that the displacement values obtained from the periodic chirp excitation showed an inconsistent linear increment with the excitation level that applied to the mass-spring system.
    Type of Medium: Online Resource
    ISSN: 1757-8981 , 1757-899X
    URL: Article
    DOI: 10.1088/1757-899X/788/1/012085
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2020
    detail.hit.zdb_id: 2506501-4
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  • 8
    Online Resource
    Online Resource
    Effect of incorporating different types of Sentang tree waste particle on the thermal stability of Wood Polymer Composite (WPC)
    IOP Publishing ; 2022
    In:  IOP Conference Series: Earth and Environmental Science Vol. 951, No. 1 ( 2022-01-01), p. 012077-
    Details
    In: IOP Conference Series: Earth and Environmental Science, IOP Publishing, Vol. 951, No. 1 ( 2022-01-01), p. 012077-
    Abstract: This article presents the potential use of tree waste materials such as the leaves (L), branches (B) and trunks (T) of Azadirachta excelsa (Sentang) tree in the production of wood polymer composite (WPC). The WPC was fabricated from high-density polyethylene (HDPE) as bonding matrix, maleic anhydride (MA) as coupling agent, and Sentang tree waste particles (L, B and T) as filler, prepared using twin-screw extruder followed by injection moulding machine. The effects of incorporating these types of Sentang tree waste particle (at 35% and 45% particles loading by weight) on the thermal stability of WPC were reported. The chemical compositions of L, B and T were also determined and their influences on the thermal stability of WPC were discussed. The thermal behaviour was determined by using thermogravimetric analysis (TGA), whereas the chemical analysis using Technical Association of the Pulp and Paper Industry (TAPPI) methods. The addition of these tree waste particles as filler has increased the thermal stability of WPC compared to virgin HDPE (without any particle incorporation). The highest mass loss was experienced by virgin HDPE. It was also observed that chemical compositions of the particles played vital role in influencing the thermal stability of WPC.
    Type of Medium: Online Resource
    ISSN: 1755-1307 , 1755-1315
    URL: Article
    DOI: 10.1088/1755-1315/951/1/012077
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2022
    detail.hit.zdb_id: 2434538-6
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  • 9
    Online Resource
    Online Resource
    Finite Element Modelling and Updating of a Thin Plate Structure using Normal Mode Analysis
    IOP Publishing ; 2021
    In:  IOP Conference Series: Materials Science and Engineering Vol. 1062, No. 1 ( 2021-02-01), p. 012059-
    Details
    In: IOP Conference Series: Materials Science and Engineering, IOP Publishing, Vol. 1062, No. 1 ( 2021-02-01), p. 012059-
    Abstract: Structural design and analysis require accurate and precise finite element model in order to have a structure with high safety conditions such as aerospace, offshore and civil structures. However, the predicted results of the finite element model are often considerably different from the experimental results due to the modelling assumptions and simplifications on the properties and parameters of the actual structure. This paper presents the finite element modelling and updating methods on the thin plate structure. The modal parameters obtained from the plate are measured by experimental modal analysis by using an impact hammer and roving accelerometers method under free-free boundary conditions. The initial modal parameters are predicted by numerical analysis using normal mode analysis via NASTRAN SOL 103. The accuracy of the natural frequencies and the mode shapes obtained from the initial finite element model are compared with the measured counterparts. The modal based updating methods using NASTRAN SOL 200 is applied to update the properties of the plate. In conclusion, updating the material properties of the plate is successfully achieved. The total error of the initial finite element model of the plate is reduce from 45.12 percent to 6.28 percent respectively.
    Type of Medium: Online Resource
    ISSN: 1757-8981 , 1757-899X
    URL: Article
    DOI: 10.1088/1757-899X/1062/1/012059
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2021
    detail.hit.zdb_id: 2506501-4
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  • 10
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    Online Resource
    Nano-micro-mili Current to Mili Voltage Amplifier for Amperometric Electrical Biosensors
    IOP Publishing ; 2020
    In:  IOP Conference Series: Materials Science and Engineering Vol. 743, No. 1 ( 2020-02-01), p. 012021-
    Details
    In: IOP Conference Series: Materials Science and Engineering, IOP Publishing, Vol. 743, No. 1 ( 2020-02-01), p. 012021-
    Abstract: Amplification of nano and mircoampere electrical signal to the detectable range is essential in the biosensor field. This research is mainly focused on design an amplifier circuit to capture and amplify three different range of current as nano, micro and mili ampere and convert it to detectable voltage range as an output signal to the processing circuit. The Proteus 8 Pro software was used to design, simulate and calibrate the amplifier circuit. Firstly, current input as mili, micro and nano current were flown through 0.1 mΩ, 10 Ω and 10 KΩ resistors, respectively to convert different current inputs to the similar range in micro voltage. The MAX 4238 opamp IC was used to amplify micro voltage to mili voltage. LM 358 dual operational amplifier was used to supply virtual ground to MAX 4238 amplifier. The amplified output voltage of three different current inputs as nano, micro and mili were nearly equal to theoretical outputs.
    Type of Medium: Online Resource
    ISSN: 1757-8981 , 1757-899X
    URL: Article
    DOI: 10.1088/1757-899X/743/1/012021
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2020
    detail.hit.zdb_id: 2506501-4
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