5,862 results
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2. Application of the Acoustic Emission Method to Ranking Fatigue Damage in the Material of the Trunnions of Drying Cylinders in Cardboard- and Paper-Making Machines
- Author
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Rastegaev, I. A., Khrustalev, A. K., Danyuk, A. V., Afanas’yev, M. A., Merson, D. L., Sevast’yanov, D. V., Melent’ev, S. V., and Plyusnin, A. D.
- Published
- 2023
- Full Text
- View/download PDF
3. Production and mechanical characterization of free-standing pigmented paper coating layers with latex and starch as binder.
- Author
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Hashemi Najafi, Seyyed Mohammad, Tajvidi, Mehdi, and Bousfield, Douglas W.
- Subjects
- *
PAPER coatings , *MECHANICAL properties of thin films , *ELASTIC modulus measurement , *STIFFNESS (Engineering) measurement , *LATEX - Abstract
The mechanical properties of paper coating layers are important in various converting processes such as printing and folding of the paper. A method was developed to produce free-standing pigmented coating layers thick enough to be tested in bending as well as tension. The mechanical properties of these coating layers were characterized. Free-standing films with two types of binder formulations, pure latex or latex-starch combinations, with different binder content were prepared through an innovative film forming method that allows uniform drying of the coating layer while minimizing cracking. Tensile and flexural samples were cut out of these films. Tensile and flexural tests were carried out on samples and the results were compared. Tensile and flexural moduli were found to be similar. However, both stress at failure and strain at failure were higher in flexural tests compared to those in tensile tests. Three different types of paper were coated with these formulations and their failure during printing was evaluated through a standard ink picking test. Papers with different basis weights and porosities were found to have different picking resistance values. An interesting result was that the picking resistance did not correlate with the elastic modulus of the coating, but with the strain at failure behavior. This result indicates that the stiffness of the coating layer is not as critical during printing compared to its flexibility. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
4. Coating factors influencing the fold cracking of coated papers
- Author
-
Qinwen Wang and Ning Ding
- Subjects
0106 biological sciences ,Coated paper ,Materials science ,Forestry ,02 engineering and technology ,Fold (geology) ,engineering.material ,021001 nanoscience & nanotechnology ,01 natural sciences ,Cracking ,Coating ,010608 biotechnology ,mental disorders ,engineering ,General Materials Science ,Composite material ,0210 nano-technology - Abstract
With the increasing popularity of coated paper, it has been more widely used in printing, publishing, product packaging and commercial promotion. However, coated paper is prone to cracks after printing and folding which exposes to a white area which is referred to as fold cracking. This study investigated the coating properties of paper and coating factors influencing the fold cracking and aimed to provide guidance on how to reduce the problems of fold cracking. This paper mainly discusses the effects of pigment proportion, binder dosage, solids content, coating thickness and calendering pressure on fold cracking of coated paper after printing. Experiments show that when the coating consisted entirely of calcium carbonate, the degree of fold cracking is most serious. With the addition of kaolin, the fold cracking reduces. When the ratio of the number of parts of calcium carbonate to kaolin is 25/75, the area of fold cracking reaches its minimum value of 10.28 %. With increasing solids content of the coating, the fold cracking decreases initially and then increases. When the solids content is 55 %, the fold cracking reaches a minimum. Increased latex content reduced coating thickness and an increase in calendering pressure gradually reduce the degree of fold cracking.
- Published
- 2020
5. Key material properties in crease cracking of kraft paper
- Author
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Swan D. Smith, Joel C. Panek, Babak Mirzaei, and Trey Harksen
- Subjects
0106 biological sciences ,Materials science ,020502 materials ,Mechanical Engineering ,General Chemical Engineering ,02 engineering and technology ,General Chemistry ,01 natural sciences ,Cracking ,0205 materials engineering ,010608 biotechnology ,Media Technology ,Key (cryptography) ,General Materials Science ,Composite material ,Material properties ,Kraft paper - Abstract
Crease cracking of paperboard is important to control for the appearance and structural integrity of packages. Crease cracking is affected by creasing operation variables, as well as the physical properties of the paperboard. However, the effects of the physical properties are not clearly known. The objectives of this work were to identify the key material properties that affect crease cracking and to clarify the effects of fiber composition and starch. Laboratory sheets were produced from bleached and refined softwood and hardwood commercial pulp at grammage and thicknesses that match a typical paperboard. To mimic papermaking operations, surface starch was applied via a bench-top size press. The sheets were creased in the lab over a range of penetration depths, and reverse-side cracking was measured. The results showed that less reverse-side cracking was correlated with higher tensile post-peak energy, a lower bending stress, and a lower z-direction (ZD) stiffness. The tensile post-peak energy is a measure of the resistance to crack growth via fiber-bridging. The bending force and the ZD stiffness influence the forces that create cracks. It was observed that decreasing the ratio of hard-wood-to-softwood content and reducing the amount of starch would both decrease crease cracking.
- Published
- 2021
6. Cracking at the fold in double layer coated paper: the influence of latex and starch composition
- Author
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Mehdi Tajvidi, Douglas W. Bousfield, and Seyyed Mohammad Hashemi Najafi
- Subjects
040101 forestry ,Coated paper ,Materials science ,Starch ,Mechanical Engineering ,General Chemical Engineering ,04 agricultural and veterinary sciences ,02 engineering and technology ,General Chemistry ,Fold (geology) ,021001 nanoscience & nanotechnology ,chemistry.chemical_compound ,Cracking ,Chemical engineering ,chemistry ,Media Technology ,0401 agriculture, forestry, and fisheries ,General Materials Science ,0210 nano-technology - Abstract
Cracking at the fold of publication and packaging paper grades is a serious problem that can lead to rejection of product. Recent work has revealed some basic mechanisms and the influence of various parameters on the extent of crack area, but no studies are reported using coating layers with known mechanical properties, especially for double-coated systems. In this study, coating layers with different and known mechanical properties were used to characterize crack formation during folding. The coating formulations were applied on two different basis weight papers, and the coated papers were folded. The binder systems in these formulations were different combinations of a styrene-butadiene latex and mixtures of latex and starch for two different pigment volume concentrations (PVC). Both types of papers were coated with single and double layers. The folded area was scanned with a high-resolution scanner while the samples were kept at their folded angle. The scanned images were analyzed within a constant area. The crack areas were reported for different types of papers, binder system and PVC values. As PVC, starch content, and paper basis weight increased, the crack area increased. Double layer coated papers with high PVC and high starch content at the top layer had more cracks in comparison with a single layer coated paper, but when the PVC of the top layer was low, cracking area decreased. No measurable cracking was observed when the top layer was formulated with a 100% latex layer.
- Published
- 2019
7. Corrosion Induced Cracking of Reinforced Concrete
- Author
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Fahy, Caroline, Grassl, Peter, Gallipoli, Domenico, Andrade, Carmen, editor, Gulikers, Joost, editor, and Polder, Rob, editor
- Published
- 2015
- Full Text
- View/download PDF
8. Fold cracking of coated papers: investigation on automated computer-aided visual assessment method
- Author
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Sandra Dedijer, Koltai László, Diana Gregor-Svetec, Magdolna Pál, Živko Pavlović, Neda Milić-Keresteš, and Tomislav Cigula
- Subjects
Cracking ,Materials science ,Fold (higher-order function) ,Visual assessment ,Computer-aided ,General Materials Science ,Forestry ,Biomedical engineering - Abstract
In this paper, white pixel percentage (WPP) value, as an overall measure of fold crack damages, has been analysed with respect to selected parameters of sample preparation and digitalization process, as well as the results of residual tensile strength. The WPP values were derived by an automated image processing algorithm, developed earlier, based on extensive comparative analysis of the existing computer-aided methods. Results indicate that WPP values correlate well with the extent of fold cracks on the coated samples, as far as the used parameters of sample preparation and digitalization are concerned. In the case of correlation with residual tensile strength, results for samples folded in cross direction revealed that the extent of the visually registered fold cracks agree well with the actual damage, while for samples folded in machine direction, the overall strength losses weren’t alarming, although the fold cracks were detected correctly. In addition, results pointed out that the simplest sample placement position (inner angle of 180°) is not applicable for realistic sample representation. Furthermore, scanners could provide a superior image quality in lab conditions, but for industry application, a camera-based solution would be more purposeful, while micrographs are more suitable for traditional visual analysis.
- Published
- 2021
9. A Study on the Quantitative Evaluation Method of Fold Cracking of Coated Paper
- Author
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Kyudeok Oh, Hak Lae, Araz Rajabi, Wanhee Im, and Jee-Hong Lee
- Subjects
Cracking ,Coated paper ,Materials science ,Evaluation methods ,Media Technology ,General Materials Science ,General Chemistry ,Fold (geology) ,Composite material - Published
- 2017
10. Cracking of Stainless Steel Suction Roll in a Paper Machine
- Author
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D. G. Chakrapani
- Subjects
Cracking ,Suction ,Materials science ,Paper machine ,business.product_category ,Composite material ,business - Abstract
Two suction rolls at the first press section of a 25 ft. wide paper machine developed cracks within two years of service. The rolls were austenitic stainless steel castings made of ASTM A 351 Grade CF8M alloy containing molybdenum. The rolls were exposed to slightly acidic white water (pH approximately 4.7) containing chlorides (45 ppm). Visual and liquid penetrant inspections of the rolls revealed extensive cracking at the roll inside surface. The cracks penetrated more than 30 percent of the wall thickness and a few cracks were several inches long. The cracks were preferentially oriented along the roll length and primarily at the roll inside surface. Field metallographic examination showed significant grain boundary chromium-carbide precipitation and intergranular corrosion. The roll failures were attributed to chromium depletion along the grain boundaries (sensitization) resulting from slow cooling of the casting to avoid large residual stresses. The roll manufacturer recommended a proprietary ferritic/austenitic stainless steel as the replacement material for the rolls.
- Published
- 2019
11. Fold Cracking of High Grammage Coated Paper Depending on Pulp Composition and Structure of Base Paper
- Author
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Hye Jung Youn, Seung Uk Yeu, Kyudeok Oh, Yong Min Lee, Hak Lae Lee, and Kyujeong Sim
- Subjects
Grammage ,Coated paper ,Softwood ,Materials science ,Pulp (paper) ,General Chemistry ,Fold (geology) ,engineering.material ,Cracking ,Kraft process ,mental disorders ,Media Technology ,engineering ,Hardwood ,General Materials Science ,Composite material - Abstract
Fold cracking is one of quality troubles of coated papers. In this study, the fold cracking of high grammage 2(250 g/m) coated paper made with the different pulp composition and layer structure of base paper was investigated. The single layered, high grammage base paper was prepared by mixing of hardwood and softwood bleached kraft pulp fibers with the different ratios. The high grammage coated paper showed the higher fold cracking than low grammage coated paper because of the increase in thickness. The increase in the content of softwood pulp fibers reduced the fold cracking in the case of high gram-mage coated paper. When the creasing process was conducted before folding process, the fold cracking of coated paper decreased. By manufacturing the base paper with multiply structure, the fold cracking of coated paper could be reduced significantly, especially when the BCTMP and OCC were used as a middle layer and the creasing process was car-ried out. The delamination of layers in base paper affected the fold cracking positively. Keywords: Fold cracking, coated paper, high grammage, multiply structure, creasing
- Published
- 2015
12. Effect of Ash Content in Base Paper on Fold Cracking of Coated Paper
- Author
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Kyu Deok Oh, Hye Jung Youn, Dong-Il Seo, and Hak Lae Lee
- Subjects
Coated paper ,Materials science ,High loading ,General Chemistry ,Fold (geology) ,engineering.material ,Water retention ,Cracking ,Coating ,mental disorders ,Ultimate tensile strength ,Media Technology ,medicine ,engineering ,Gravimetric analysis ,General Materials Science ,medicine.symptom ,Composite material - Abstract
High loading of base paper is regarded as one of reasons to aggravate fold cracking of coated paper. But the relationship between the ash content of base paper and fold cracking of coated paper has not been shown yet. We investigated the effect of ash content in base paper on the fold cracking of coated paper. Handsheets with three different ash contents (19.5-23.5%) were prepared, and double layered coating were applied on the top side of the handsheets. A gravimetric water retention meter (AA-GWR) was employed to fold the paper with a uniform pressure after solid printing on the coated surface. The fold cracking was digitized by calculating the cracked area by means of an image analysis technique. Results suggested that high ash content in the base paper increased the fold cracking of the outer surface of coated papers. In the case of inner surface greater fold crack areas were obtained, and the number of cracks decreased because long and wide cracks were formed. Reduction in tensile strength and thickness appeared to give greater fold cracking for highly loaded papers.
- Published
- 2015
13. Exploring the feasibility of using reclaimed paper-based asphalt felt waste as a modifier in asphalt-binders
- Author
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Xiaodi Hu, Pan Pan, Xifan Li, Lubinda F. Walubita, Silei Fan, and Luis Fuentes
- Subjects
Waterproofing ,Waste management ,Rut ,0211 other engineering and technologies ,Modulus ,020101 civil engineering ,02 engineering and technology ,Building and Construction ,Paper based ,0201 civil engineering ,Cracking ,Laboratory test ,Asphalt ,021105 building & construction ,Environmental science ,General Materials Science ,Civil and Structural Engineering ,Waste disposal - Abstract
Paper-based asphalt felt, which is typically used as a waterproofing material, is one of the most problematic solid wastes in terms of disposal and environmental contamination. The laboratory work presented in this paper aims to propose a strategy for utilizing the reclaimed paper-based asphalt felt (RPAF) waste in hot-mix asphalt (HMA) pavements as a means to mitigate the RPAF disposal problem. A series of laboratory tests, including viscosity, modulus, rutting, and cracking, were conducted to investigate the effects of RPAF additives on the engineering performance of asphalt-binder and HMA mixes. The corresponding test results showed that the addition of RPAF improves the viscosity and high-temperature performance of asphalt-binders. However, RPAF modified asphalt-binder exhibited inferior storage stability than the virgin asphalt-binder due to the difference in density between the asphalt-binder and RPAF components. Additionally, the effect of RPAF on the rheological characteristics of the asphalt-binder exhibited high sensitivity to temperature. The differences in complex modulus and phase angle of the asphalt-binder with RPAF additives were generally more significant at elevated temperatures. Similarly, RPAF modified HMA mixes outperformed the control HMA mix in terms of resistance to moisture damage, rutting, and cracking, respectively. Overall, the laboratory test results indicated that it is feasible to utilize RPAF waste as an asphalt-binder modifier to enhance the engineering properties/performance of the asphalt-binder and HMA mix whilst simultaneously addressing the environmental issues of RPAF waste disposal.
- Published
- 2020
14. Effects of coating composition and folding direction on the fold cracking of coated paper
- Author
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Dong-Il Seo, Yong Min Lee, Kyudeok Oh, Hak Lae Lee, Seung Uk Yeu, and Hye Jung Youn
- Subjects
0106 biological sciences ,Coated paper ,Materials science ,Forestry ,02 engineering and technology ,Fold (geology) ,engineering.material ,021001 nanoscience & nanotechnology ,01 natural sciences ,Cracking ,Coating ,010608 biotechnology ,engineering ,General Materials Science ,Composite material ,0210 nano-technology - Published
- 2016
15. Effects of Preflocculated Filler Flocs and Nano-sized Coating Binder on Fold Cracking of Coated Paper
- Author
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Hak Lae Lee, Hye Jung Youn, Young Bin Jeong, Wanhee Im, Kyudeok Oh, and Dong-Il Seo
- Subjects
Cracking ,Coated paper ,Materials science ,Coating ,Floc size ,Media Technology ,engineering ,General Materials Science ,General Chemistry ,Composite material ,engineering.material ,Nano sized - Published
- 2015
16. Simulation-Based Stochastic Method to Model Microcrack Coalescence in Asphalt Pavements: Concept Paper
- Author
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Frederick Kautz and Rajib B. Mallick
- Subjects
Coalescence (physics) ,Cracking ,Materials science ,Asphalt pavement ,Asphalt ,Fatigue testing ,Transportation ,Geotechnical engineering ,Simulation based ,Civil and Structural Engineering - Abstract
Fatigue cracking is a major distress in hot mix asphalt (HMA) pavements. The coalescence of microcracks into macrocracks has been widely recognized as a prevalent cause of fatigue failure i...
- Published
- 2021
17. Syngas production from co-pyrolysis and co-gasification of polystyrene and paper with CO2
- Author
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Paramvir Singh, N. Déparrois, K. G. Burra, and Ashwani K. Gupta
- Subjects
Thermogravimetric analysis ,Materials science ,020209 energy ,Mechanical Engineering ,02 engineering and technology ,Building and Construction ,Management, Monitoring, Policy and Law ,Waste-to-energy ,Cracking ,chemistry.chemical_compound ,General Energy ,020401 chemical engineering ,chemistry ,Chemical engineering ,0202 electrical engineering, electronic engineering, information engineering ,Polystyrene ,Gas chromatography ,Char ,0204 chemical engineering ,Chemical composition ,Syngas - Abstract
Co-pyrolysis and CO2 co-gasification of paper and polystyrene blends in different mixture ratios were studied at 1173 K using a laboratory scale tube reactor and thermogravimetric analysis. The chemical composition and yield of the syngas produced was analyzed by a micro gas chromatograph to understand the influence of mixture components. Co-pyrolysis positively impacted the syngas yield exhibiting a synergistic influence on cracking reactions leading to increased gaseous yield having almost double the amounts of hydrogen yield. Co-gasification using CO2 increased the total gas yield with enhanced synergistic conversion. This effect provided a non-linear impact on the combustible gases in the gaseous yields when compared to the separate gasification of these feedstocks. The synergistic enhancement of co-pyrolysis conversion in paper-polystyrene led to lower char present for CO2 to react during CO2 co-gasification that lead to lower CO during the gasification of this blended char residue. The mixtures of paper with polystyrene provided increased product gas yields and enhanced conversion with an increase in polystyrene content. The results showed the effectiveness of producing high energy density syngas from co-gasification which can alleviate material handling issues present in segregation of waste, such as plastics and biomass providing uniform valuable product from diverse waste feedstocks with minimal need for classification.
- Published
- 2019
18. Effect of coating binder on fold cracking of coated paper
- Author
-
Lee
- Subjects
Coated paper ,Cracking ,Materials science ,Coating ,engineering ,General Materials Science ,Forestry ,Fold (geology) ,Composite material ,engineering.material - Published
- 2015
19. Effect of coating binder on fold cracking of coated paper
- Author
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Hak Lae Lee, Kyujeong Sim, Young Bin Jeong, Seung Uk Yeu, Hye Jung Youn, Yong Min Lee, and Kyudeok Oh
- Subjects
Coated paper ,Cracking ,Materials science ,Fold (higher-order function) ,Coating ,engineering ,General Materials Science ,Forestry ,engineering.material ,Composite material - Published
- 2015
20. Important Factors on the Failure of Pipeline Steels with Focus on Hydrogen Induced Cracks and Improvement of Their Resistance: Review Paper
- Author
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M.A. Mohtadi-Bonab and H. Ghesmati-Kucheki
- Subjects
Materials science ,Metallurgy ,Metals and Alloys ,Fracture mechanics ,Condensed Matter Physics ,Microstructure ,Stress (mechanics) ,Cracking ,Mechanics of Materials ,Materials Chemistry ,Grain boundary ,Texture (crystalline) ,Stress corrosion cracking ,Electron backscatter diffraction - Abstract
Currently, thousands of kilometers of pipeline steels are transferring hydrocarbon fluids such as oil and natural gas in the world. Due to the fact that these pipes transport corrosive and high-pressure fluids from harsh environments, they are damaged and eventually degraded. Previous studies showed that sulphide stress cracking, hydrogen induced cracking (HIC) and stress corrosion cracking are the main destructive factors in these types of pipes. This paper focused on the HIC related failure in pipeline steel, since the role of texture and grain boundary character has not been completely recognized. Moreover, if pipeline damage is occurred by hydrogen cracks, besides the environmental pollutions, it will cost a lot to repair or replace the damaged pipeline steels. In this research, the factors influencing the initiation and propagation of the HIC cracks, such as hydrogen traps, inclusions, precipitates, microstructure and texture of steel have been investigated. Also, the existing solutions for improving the steel resistance to the HIC have been investigated based on the control of micro-alloy elements, texture and grain boundary engineering. For instance, some special dominant texture components and coincidence site lattice boundaries decrease the HIC susceptibility by providing the resistant path for crack propagation.
- Published
- 2019
21. Catalytic Cracking of Primary Tar Vapor from Biomass over High Ash-Containing Paper Sludge Ash
- Author
-
Kuangye Peng, Zhonghao Rao, Yuping Dong, Xingmin Zhao, Feiqiang Guo, and Tiantao Li
- Subjects
Thermogravimetric analysis ,Chemistry ,020209 energy ,General Chemical Engineering ,Energy Engineering and Power Technology ,Tar ,Biomass ,02 engineering and technology ,urologic and male genital diseases ,Fluid catalytic cracking ,complex mixtures ,Decomposition ,Catalysis ,Cracking ,Fuel Technology ,Chemical engineering ,0202 electrical engineering, electronic engineering, information engineering ,Pyrolysis - Abstract
High ash-containing paper sludge ash (PSA) has been investigated in terms of its use as a low-cost catalyst for primary pyrolysis tar cracking in the two-stage pyrolysis of biomass. Experimental results showed that tar yields decreased significantly using PSA as catalyst in comparison with the thermal cracking experiments. A consequent increase in total gas yield was obtained. The yields of H2, CH4, and CO2 increased significantly under the catalytic effect of PSA, particularly the H2 yield almost doubled, while CO yields showed a slight decrease due to the consumption reactions. Thermogravimetric analysis of the fresh and spent PSA showed that carbon particles formed along with the tar decomposition, while the catalytic reactivity of the PSA was not reduced because of the participation of carbon particles in tar reforming. XRD spectrograms revealed that calcium-ferrite oxide (Ca2Fe2O5) was formed in PSA, which has excellent stability and catalytic effect on tar cracking and H2 production. The PSA still s...
- Published
- 2018
22. Experimental analysis of one-way composite steel deck slabs voided by circular paper tubes: Shear strength and moment–shear interaction
- Author
-
Eungsoo Kim, Jaeho Ryu, Iman Mansouri, Woon-Taek Woo, and Chang-Hwan Lee
- Subjects
Constructability ,Cracking ,Materials science ,Flexural strength ,Shear (geology) ,business.industry ,Composite number ,Slab ,Structural engineering ,Reinforcement ,business ,Civil and Structural Engineering ,Deck - Abstract
In order to improve structural efficiency, environmental performance, and constructability, a new type of one-way composite voided slab system (TUBEDECK) has been recently proposed which combines profiled steel decks with cast-in-situ RC slabs. Because eliminating concrete volume to optimize flexural strength can significantly reduce the shear strength of nonprestressed concrete or composite slabs without shear reinforcement, a clarification of the shear resistance capacity is required. In this study, shear tests on a total of 12 specimens were conducted with slab thickness, the presence or absence of voids and/or steel decks, and tension reinforcement ratio as variables. The results show that combined flexure and shear dominated the behavior of both voided (V) slabs and TUBEDECK (TD) slabs, and web-shear cracking did not affect strength. Predicted shear strength based on the minimum web width was too conservative. Conversely, the shear strength prediction equations, which were proposed on the basis of the real cross-sectional area of concrete, predicted the capacity of both V slabs and TD slabs from a reasonably conservative perspective. A discussion on the influence of moment–shear interaction is also included, and an interaction design model is proposed in a further investigation.
- Published
- 2019
23. Catalytic Steam Reforming of Heavy Oilstock: Review Paper
- Author
-
V. A. Yakovlev, G. A. Sosnin, O. O. Mironenko, P. M. Eletsky, and R. G. Kukushkin
- Subjects
Visbreaker ,Hydrogen ,business.industry ,chemistry.chemical_element ,Coke ,Fluid catalytic cracking ,Supercritical fluid ,Catalysis ,Steam reforming ,Cracking ,chemistry ,Environmental science ,Process engineering ,business - Abstract
Deterioration of the quality of oilstock makes it an urgent problem to use non-traditional hydrocarbon materials (heavy oil, bitumen, residues etc.). Processing of heavy oilstock (HOS) needs new methods that would be effective for the yields of light fractions, suppression of coke formation, and saturation of the liquid products with hydrogen. At the same time, expenses of HOS extraction and transportation are several times as high as those of light and middle oils that makes it necessary to minimize the capital and operational costs for the process. The review paper integrates for the first time the results of the studies of catalytic steam reforming of HOS as a potential alternative of the traditional processes for HOS upgrading based on decreasing the carbon content (thermal cracking, visbreaking, catalytic cracking) or on the saturation of liquid products with hydrogen (hydrocracking). Under discussion are main distinctions of the process from HOS upgrading with water (hydropyrolysis in sub- or supercritical water) as well as specific features of the catalytic steam cracking as dependent on the process parameters and catalysttype and putative mechanisms of the participation of water in the process.
- Published
- 2018
24. Analysis of cracking evolution mode of the monobloc sleeper
- Author
-
Tahi, Mohammed, Chikhaoui, Mohamed, and Chabaat, Mohamed
- Published
- 2023
- Full Text
- View/download PDF
25. Tribocorrosion behaviour of thermally sprayed cermet coatings in paper machine environment
- Author
-
Helena Ronkainen, Elina Huttunen-Saarivirta, Lauri Kilpi, Vuokko Heino, and Elisa Isotahdon
- Subjects
Materials science ,Cermet ,Tribocorrosion ,Mechanical Engineering ,Abrasive ,Metallurgy ,02 engineering and technology ,Surfaces and Interfaces ,021001 nanoscience & nanotechnology ,Surfaces, Coatings and Films ,Corrosion ,Cracking ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Mechanics of Materials ,0210 nano-technology ,Thermal spraying ,Porosity ,Abrasive wear ,Thermally sprayed coating ,Tribometer - Abstract
Tribocorrosion behaviour of thermally sprayed cermet coatings: WC-CoCr deposited by HVOF and HVAF and Cr3C2-WC-NiCrCo applied by HVAF, was examined in paper machine environment in a pin-on-disc tribometer under the load of 20 N in electrolyte containing chlorides and sulphates, pH 4.5. Wear was the dominant degradation mechanism for all coatings, followed by corrosion-induced wear, the importance of which increased with rising potential. The overall material losses were lowest for HVAF WC-CoCr and highest for HVAF Cr3C2-WC-NiCrCo, the latter being related to the evident abrasive wear of the Cr3C2 phase and cracking along Cr3C2-matrix interface in the near-surface areas. Among the three coatings, contribution by corrosion to the damage was greatest in HVOF WC-CoCr, likely due to high degree of porosity.
- Published
- 2020
26. Behaviors of Reinforced Concrete Slab Voided by Circular Paper Tubes
- Author
-
Mamush Teklie, Tesfaye Alemu, and Beka Benti
- Subjects
Cracking ,Toughness ,Materials science ,Compressive strength ,Flexural strength ,Void (composites) ,medicine ,Slab ,Stiffness ,Composite material ,medicine.symptom ,Ductility - Abstract
Voided slab construction is a way of effectively removing concrete from middle section of a RC slab which has not a structural function, thereby reducing structural dead weight. Voided slab construction has advantages such as reducing self-weight, Cost efficiencies and fast Construction. However, floor stiffness of voided RC slab is less than its solid counterpart and there is gap in literature about structural behaviors of voided RC slabs. This research work presents experimental and numerical investigations of voided RC slab. Six solid and voided RC slab specimens of size 800mmx300mmx200mm were casted and tested until failure under one-point load. Also, leveraging advantages of FEA, effect of influential variables such as void size, loading type, concrete compressive strength, and effect of top reinforcement were thoroughly studied. Experimental test results indicated as compared to control solid RC slab, 60mm diameter paper tube voided RC slab exhibited 12%, 15.54%, 25.50%, 14.64% and 6.71% loss in strength, cracking load, stiffness, ductility, and toughness respectively where as for 90mm diameter paper tube voided RC slab respective values were 20%, 19.87%, 38.80%, 25.50% and 12%. Also, as void size increased from 60mm to 90mm, voided slab failure mode changed from flexural to shear. Finally, FEA, ACI 318M-19 and EC2 codes showed good agreement with experimental results.
- Published
- 2020
27. Analysis of the concrete shrinkage effects on the real behavior of the spatial concrete and reinforced concrete structures using the thermal analogy
- Author
-
Džolan, Ante, Kožul, Mladen, Harapin, Alen, and Ćubela, Dragan
- Published
- 2020
- Full Text
- View/download PDF
28. Flowers Cracking Concrete: Eiko & Koma's Asian/American Choreographies by Rosemary Candelario . 2016. Middletown, CT: Wesleyan University Press. 302 pp., 18 illustrations, notes, bibliography, index. $80.00 cloth, ISBN: 9780819576477; $26.95 paper, ISBN: 9780819576484
- Author
-
Mana Hayakawa
- Subjects
Cracking ,History ,Visual Arts and Performing Arts ,Asian americans ,Ancient history - Published
- 2017
29. Reply to the discussion by S.G. Hansen of the paper 'ASR expansion, expansive pressure and cracking in concrete prisms under various degrees of restraint'
- Author
-
Yukihiro Yasuda, Hiroyuki Kagimoto, and Mitsunori Kawamura
- Subjects
Cracking ,Chemistry ,021105 building & construction ,0211 other engineering and technologies ,Forensic engineering ,General Materials Science ,02 engineering and technology ,Building and Construction ,021001 nanoscience & nanotechnology ,0210 nano-technology ,Expansive - Published
- 2016
30. Exploring the feasibility of using reclaimed paper-based asphalt felt waste as a modifier in asphalt-binders.
- Author
-
Hu, Xiaodi, Fan, Silei, Li, Xifan, Pan, Pan, Fuentes, Luis, and Walubita, Lubinda F.
- Subjects
- *
CRUMB rubber , *ASPHALT , *ASPHALT modifiers , *SEWAGE disposal , *FATIGUE life , *HIGH temperatures , *SOLID waste - Abstract
• It is feasible to use paper-based asphalt felt (RPAF) waste in asphalt mixtures. • The effects of RPAF on the rheological property of asphalt-binders is a function of temperature. • Asphalt mixtures with RPAF exhibited better moisture stability and anti-rutting property. • The fatigue life of the asphalt mixtures increased with the addition of RPAF. Paper-based asphalt felt, which is typically used as a waterproofing material, is one of the most problematic solid wastes in terms of disposal and environmental contamination. The laboratory work presented in this paper aims to propose a strategy for utilizing the reclaimed paper-based asphalt felt (RPAF) waste in hot-mix asphalt (HMA) pavements as a means to mitigate the RPAF disposal problem. A series of laboratory tests, including viscosity, modulus, rutting, and cracking, were conducted to investigate the effects of RPAF additives on the engineering performance of asphalt-binder and HMA mixes. The corresponding test results showed that the addition of RPAF improves the viscosity and high-temperature performance of asphalt-binders. However, RPAF modified asphalt-binder exhibited inferior storage stability than the virgin asphalt-binder due to the difference in density between the asphalt-binder and RPAF components. Additionally, the effect of RPAF on the rheological characteristics of the asphalt-binder exhibited high sensitivity to temperature. The differences in complex modulus and phase angle of the asphalt-binder with RPAF additives were generally more significant at elevated temperatures. Similarly, RPAF modified HMA mixes outperformed the control HMA mix in terms of resistance to moisture damage, rutting, and cracking, respectively. Overall, the laboratory test results indicated that it is feasible to utilize RPAF waste as an asphalt-binder modifier to enhance the engineering properties/performance of the asphalt-binder and HMA mix whilst simultaneously addressing the environmental issues of RPAF waste disposal. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
31. The uniaxial compressive strength of concrete: revisited.
- Author
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Yankelevsky, David Z.
- Abstract
This paper re-examines common notions and conventions regarding the compressive strength of concrete in general and of the uniaxial compressive strength of concrete in particular. A distinction is introduced between the strength of the specimen and the strength of the concrete as a material, and the commonly measured and adopted strength is shown to be the specimen's strength, wrongly interpreted as the material's strength. the two major damage modes of concrete specimens (with the formation of either longitudinal cracks or shear bands) are discussed. Such failure modes are wrongly considered as features of concrete behavior in uniaxial compression, but this is not the case. Longitudinal cracking is due to lateral expansion (Poisson's effect) and occurs at a relatively low applied load in absence of friction at specimen's top and bottom boundaries. Shear failure (accompanied by the formation of an inclined shear band) is related to the shear envelope parameters that are related to the concrete mixture, but the applied ultimate pressure is not the concrete uniaxial compressive strength. Hence, though caused by applied compressive loading, these failure modes are little/hardly related to the concrete material intended as the ultimate uniaxial stress (strength) corresponding to a maximum value of the uniaxial compressive strain. Using the shear envelope parameters has been proven to yield a very good prediction of the applied compressive loading of the specimen in the limit state, as a demonstration that the applied pressure at specimen's failure resulting from the formation of inclined fracture bands is the specimen's failure strength, and not the material's compressive strength! Reasons are given against the existence of a uniaxial compressive strength failure for concrete, and a piece of evidence in this direction is provided by concrete specimens subjected to pure hydrostatic compression, that do not fail at all. The entire issue requires, therefore, a deep revisiting and re-thinking, to provide correct measures for representing concrete response under compression in analysis and design. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
32. Electron Microscopy on Mechanism of Voidage and Cracking in Si by Injection of a Permeable Infra-Red Laser.
- Author
-
Hiroyuki Iwata and Hiroyasu Saka
- Subjects
ELECTRON microscopy ,INFRARED lasers ,INFRARED radiation ,SEMICONDUCTOR devices ,LASERS - Abstract
Si is opaque to visible light, but transparent to infrared rays. Therefore, when the infrared laser is focused inside Si, the focal portion becomes ultra-hot, forming a modified volume (Laser induced modified volume: LIMV) inside. After the laser beam is injected into the Si wafer at equal intervals (for example, 5 µm) in the cross direction, and then a force is applied from the outside. Then, cracks are formed from LIMV, and the Si wafer is divided into small pieces of 5 µm square. This is the stealth dicing (SD) technology, which is now widely used in the manufacture of semiconductor devices. In this process, clarifying the nature of LIMV is of great industrial and academic significance. The authors have been engaged in elucidating the mechanism of LIMV development by TEM observation. This phenomenon, which at first seemed extremely puzzling, was finally elucidated. In this overview, we would like to describe the process that led to this elucidation in chronological order. This phenomenon is extremely puzzling, and due to the author’s lack of knowledge, there were errors in the contents of the papers published so far, so we have corrected them in this overview. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. Numerical algorithm of reinforced concrete lining cracking process for pressure tunnels
- Author
-
Zhang, Wei, Dai, Beibing, Liu, Zhen, and Zhou, Cuiying
- Published
- 2018
- Full Text
- View/download PDF
34. LOCALIZATION ANALYSIS OF AN ORTHOTROPIC MULTI-SURFACE PLASTICITY MODEL UNDER UNIAXIAL STRESS
- Author
-
Martin Horák, Claudio Pagani, and Milan Jirásek
- Subjects
Materials science ,business.industry ,multi-surface plasticity, localization, weak discontinuity, masonry ,Short paper ,Mechanics ,Plasticity ,Masonry ,Orthotropic material ,Cracking ,lcsh:TA1-2040 ,General Earth and Planetary Sciences ,Principal stress ,business ,lcsh:Engineering (General). Civil engineering (General) ,Softening ,General Environmental Science ,Principal axis theorem - Abstract
Numerical simulations of masonry structures are often based on continuum macromodelling approaches that need constitutive laws able to phenomenologically reproduce the behavior of the material. To capture the deformation process up to failure, appropriate softening laws are needed to take into account the contraction of the yield stress domain caused by cracking and crushing. It is well known that softening may lead to localization of inelastic strain. This paper focuses on localization analysis of an orthotropic macro-scale model in the framework of multi-surface plasticity, which describes the in-plane behavior of masonry structures. Preliminary results reported in this short paper are limited to uniaxial stress states. Analytical localization conditions are first derived for uniaxial stress states with principal axes aligned with the material axes of orthotropy. Then, localization analysis is extended to an arbitrary angle between the principal stress axes and the axes of orthotropy.
- Published
- 2020
35. Recovery of renewable carbon resources from the household kitchen waste via char induced microwave pyrolysis
- Author
-
Dadi V. Suriapparao and Ravikrishnan Vinu
- Subjects
Materials science ,Renewable Energy, Sustainability and the Environment ,business.industry ,chemistry.chemical_element ,Pulp and paper industry ,Renewable energy ,law.invention ,Cracking ,chemistry ,law ,Biochar ,Char ,business ,Selectivity ,Carbon ,Pyrolysis ,Susceptor - Abstract
This study is focused on creating value addition to kitchen waste (KW) by converting it into valuable product resources via microwave pyrolysis. The effect of the following on product yields and energy efficiency were examined in this study: (i) microwave power (140–700 W), (ii) KW: susceptor ratio (20:0 to 20:20 (g/g)), and (iii) pyrolysis temperature (200–600 °C). The KW was pyrolyzed without the addition of a susceptor and char formed during pyrolysis acted as a susceptor and enhanced pyrolysis energy efficiency (78%). An increase in microwave power has significantly increased the heating rate from 4 to 85 °C/min, and KW has produced 73 wt% of bio-oil and gases even at low microwave power (140 W). An increase in pyrolysis temperature promoted thermal cracking of KW, which resulted in decreased char yields (64–27 wt%), and an increase in gas yields (12–45 wt%). Bio-oil contains a significant amount of phenolics (35–50%) and its selectivity varied significantly with the variables probed. The selectivity of furan derivatives has dramatically decreased from 45 to 20% with the increase in pyrolysis temperature. This work demonstrated the feasibility of valorization of kitchen waste into various value-added products.
- Published
- 2021
36. Conversion of Palm Oil (CPO) into Fuel Biogasoline through Thermal Cracking Using a Catalyst Based Na-Bentonite and Limestone of Soil Limestone NTT
- Author
-
Daniel Silalahi, Muhammad Taufik, and Minto Supeno
- Subjects
Cracking ,Materials science ,Bentonite ,Thermal ,Palm oil ,Pulp and paper industry ,Biogasoline ,Catalysis - Abstract
Cracking catalytic palm oil (CPO) into hydrocarbon fuel by saponification pretreatment has been carried out with bentonite and limestone-based catalysts. The catalysts used were Na-bentonite and Limestone NTT which were first analyzed using XRF, XRD, and SEM. Saponification pretreatment was carried out on CPO to facilitate the cracking process using a catalyst. The saponification product in the form of a mixture of soap and glycerol was then analyzed by DSC to determine the degradation temperature. Catalytic cracking is carried out in two stages, namely, the first stage hydrocracking at a temperature of 250-350°C using a stainless steel reactor is the source of catalyst Fe / Cr. The resulting distillate was then cracked again using a Na-bentonite catalyst and a TKNTT catalyst. The resulting fuel is a hydrocarbon fuel which is confirmed from the FT-IR results which indicate the presence of long-chain hydrocarbon compounds. This data is also supported by the results of the GC-MS analysis which shows that the fuel fraction produced is mostly biogasoline. Where cracking using a Na-bentonite catalyst produces a biogasoline fraction of 61.36% and a biodiesel fraction of 38.63%, THAT produces a biogasoline fraction of 88.88% and a biodiesel fraction of 11.11%. The characteristics of the hydrocarbon fuels that have been analyzed show that the calorific value of combustion is 6101 cal/g which is determined using a bomb calorimeter, and the cetane index is 62 which is analyzed using CCI. Both types of hydrocarbon fuels have met the physical requirements that must be possessed by biogasoline fuel based on SNI standards.
- Published
- 2021
37. Detailed investigations of the influence of catalyst packing porosity on the performance of THAI-CAPRI process for in situ catalytic upgrading of heavy oil and bitumen
- Author
-
Ado, Muhammad Rabiu
- Subjects
Enhanced oil recovery (EOR) ,Waste management ,Hydrogen ,Heavy oil/bitumen/tar sand ,Original Paper-Production Engineering ,chemistry.chemical_element ,Reservoir simulation ,In situ catalytic upgrading ,Geotechnical Engineering and Engineering Geology ,Combustion ,Environmentally friendly ,Catalysis ,API gravity ,Cracking ,General Energy ,chemistry ,Asphalt ,In situ combustion (ISC) ,Porosity ,Toe-to-heel air injection (THAI) - Abstract
Heavy oils and bitumen are indispensable resources for a turbulent-free transition to a decarbonized global energy and economic system. This is because according to the analysis of the International Energy Agency’s 2020 estimates, the world requires up to 770 billion barrels of oil from now to year 2040. However, BP’s 2020 statistical review of world energy has shown that the global total reserves of the cheap-to-produce conventional oil are roughly only 520.2 billion barrels. This implies that the huge reserves of the practically unexploited difficult-and-costly-to-upgrade-and-produce heavy oils and bitumen must be immediately developed using advanced upgrading and extraction technologies which have greener credentials. Furthermore, in accordance with climate change mitigation strategies and to efficiently develop the heavy oils and bitumen resources, producers would like to maximize their upgrading within the reservoirs by using energy-efficient and environmentally friendly technologies such as the yet-to-be-fully-understood THAI-CAPRI process. The THAI-CAPRI process uses in situ combustion and in situ catalytic reactions to produce high-quality oil from heavy oils and bitumen reservoirs. However, prolonging catalyst life and effectiveness and maximizing catalytic reactions are a major challenge in the THAI-CAPRI process. Therefore, in this work, the first ever-detailed investigations of the effects of alumina-supported cobalt oxide–molybdenum oxide (CoMo/γ-Al2O3) catalyst packing porosity on the performance of the THAI-CAPRI process are performed through numerical simulations using CMG STARS. The key findings in this study include: the larger the catalyst packing porosity, the higher the accessible surface area for the mobilized oil to reach the inner coke-uncoated catalysts and thus the higher the API gravity and quality of the produced oil, which clearly indicated that sulphur and nitrogen heteroatoms were catalytically removed and replaced with hydrogen. Over the 290 min of combustion period, slightly more oil (i.e. an additional 0.43% oil originally in place (OOIP)) is recovered in the model which has the higher catalyst packing porosity. In other words, there is a cumulative oil production of 2330 cm3 when the catalyst packing porosity is 56% versus a cumulative oil production of 2300 cm3 in the model whose catalyst packing porosity is 45%. The larger the catalyst packing porosity, the lower the mass and thus cost of the catalyst required per m3 of annular space around the horizontal producer well. The peak temperature and the very small amount of produced oxygen are only marginally affected by the catalyst packing porosity, thereby implying that the extents of the combustion and thermal cracking reactions are respectively the same in both models. Thus, the higher upgrading achieved in the model whose catalyst packing porosity is 56% is purely due to the fact that the extent of the catalytic reactions in the model is larger than those in the model whose catalyst packing porosity is 45%.
- Published
- 2021
38. Development of a comprehensive simulation model for H2-rich syngas production by air–steam gasification of biomass
- Author
-
Leijie Fu, Yan Cao, and Yu Bai
- Subjects
Cracking ,Wood gas generator ,Yield (chemistry) ,Tar ,Biomass ,Environmental science ,Gas composition ,Physical and Theoretical Chemistry ,Condensed Matter Physics ,Solid fuel ,Pulp and paper industry ,Syngas - Abstract
Gasification is a multiphase process that converts the solid fuels into useful synthetic gas. Despite the potential of biomass gasification as a clean technique to produce a high caloric value syngas, it is not as well looked upon as its advantages suggest. In the present study, an ASPEN plus model of biomass gasification was developed with considering the kinetics of the reactions and tar cracking mechanism. Firstly, the model was validated against the experimental data in the literature. Next, a parametric study was done to investigate and evaluate the performance and produced gas composition of air–steam gasification of biomass. The effect of various operational parameters, such as the reaction temperature, equivalence ratio (ER) and steam/biomass ratio (S/B) on the gas product composition, products yield and the gasifier performance was investigated. The results showed that the increase of reaction temperature not only can enhance the H2 content in the gas stream, but inhibit the formation of tar. The achieved optimal conditions for production of maximum H2 content (16.18 vol %) were as follows: reaction temperature of 800 °C, S/B of 0.8 and ER of 0.211.
- Published
- 2021
39. Steam co-gasification of Japanese cedarwood and its commercial biochar for hydrogen-rich gas production
- Author
-
Yutaka Kasai, Nichaboon Chaihad, Suwadee Kongparakul, Tao Yu, Aisikaer Anniwaer, Abuliti Abudula, Guoqing Guan, Chanatip Samart, and Aghietyas Choirun Az Zahra
- Subjects
Materials science ,Hydrogen ,Renewable Energy, Sustainability and the Environment ,Carbonization ,Mixing (process engineering) ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Tar ,Condensed Matter Physics ,Pulp and paper industry ,complex mixtures ,Cracking ,Fuel Technology ,chemistry ,Yield (chemistry) ,Biochar ,Syngas - Abstract
In this study, steam gasification and co-gasification of Japanese cedarwood and its commercial biochar were performed in a lab-scale fixed-bed reactor to investigate the feasibility for producing H2-rich syngas. Ultimate analysis, proximate analysis, Brunauer-Emmett-Teller (BET) surface area analysis, and scanning electron microscopy (SEM) were conducted to understand the changes caused by the carbonization process. The effects of gasification temperature and steam flow rate on gas production yield from the steam gasification of the individual samples were investigated at first, which showed larger gas production yield and less tar yield for the steam gasification of the commercial biochar than that of raw cedarwood, indicating that the commercial biochar obtained from the carbonization process was more beneficial for the gasification. The co-gasification of raw Japanese cedarwood and its commercial biochar with different mixing ratios was conducted at different reaction temperatures. The synergistic effect was obviously observed. Especially, the commercial biochar with the highly porous structure and high content of alkali and alkaline earth metal (AAEM) species might provide the catalytic effect on cracking and reforming of tar derived from the raw cedarwood, resulting in a larger H2 yield. However, the catalytic effect and gasification reactivity of biochar would decrease by increasing the amount of raw-cedarwood in the blends due to the coke deposition on the surface of biochar.
- Published
- 2021
40. Fracture Mechanisms of Lead Zirconate Titanate Piezoelectric Thin Films Determined by Mechanical and Electrical Cyclic Loading Tests.
- Author
-
Yuga Kumakiri, Tomohiro Date, Noriyuki Shimoji, Koji Terumoto, and Takahiro Namazu
- Subjects
PIEZOELECTRIC thin films ,LEAD zirconate titanate ,CYCLIC loads ,ELECTRICAL load ,STRAINS & stresses (Mechanics) ,FOCUSED ion beams - Abstract
In this paper, we describe the fracture mechanisms of lead zirconate titanate (PZT) piezoelectric thin films synthesized by sol-gel processing. One of the technical concerns in piezoelectric thin films is how their surface fractures because, in most cases, the films fail electrically, and the fracture surface is remade after its first fracture. To estimate the failure mechanisms, cantilever-type and clamped capacitor-type actuators made of PZT piezoelectric thin films deposited on a Si wafer were prepared and subjected to electrical and mechanical stresses. The cantilever-type actuators showed a decreasing trend in dielectric withstand voltage with increasing number of mechanical loading cycles. The clamped capacitor-type actuators showed a decreasing trend in withstand voltage with increasing cyclic voltage amplitude. Through mechanical and electrical experiments, we found that the origin of cracking differed from that of short circuit. This finding indicates that the PZT films fractured mechanically, then fractured electrically. The focused ion beam fabrication of a surface defect and scanning electron microscopy observation around the defect suggest a reasonable fracture mechanism. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. Modification of the Mohr–Coulomb Criterion and Its Application in the Cracking of Ring-Stiffened Cylinders Made of Titanium Alloy.
- Author
-
Yu, Xiangyu, Xu, Kewang, Xu, Qiang, Zhang, Aifeng, and Zhang, Hao
- Abstract
TC4 ELI alloy is widely used in the marine, medicine, and aviation fields. The failure performance of TC4 ELI alloy is significantly different from that of other metal materials, such as steels. In this paper, a modified Mohr–Coulomb criterion is calibrated based on several kinds of specimens under different stress states and a 3D geometric representation of a modified Mohr–Coulomb fracture locus for TC4 ELI is obtained based on these parameters. The effectiveness of the modified M-C criterion is studied by a ring-stiffened cylinder made of TC4 ELI. The ultimate strength of the cylinder obtained in the simulation with the modified M-C criterion is close to that obtained in an external pressure experiment, which shows that the modified M-C criterion is suitable for predicting failure in pressure hulls made of titanium alloy used in the deep-sea field. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
42. Cracking of Resinous-Asphaltene Extra-Heavy Oil Compounds on the Highly Developed Surface of a Coal Additive.
- Author
-
Zaitseva, E. G., Gilyazev, R. I., Onishchenko, Ya. V., Vakhin, A. V., Petrov, S. M., and Bashkirtseva, N. Yu.
- Subjects
AMORPHOUS carbon ,SCANNING electron microscopy ,AROMATIC compounds ,ALKANES ,SURFACE area - Abstract
The paper presents the results of cracking of extra-heavy oil in the pore space of a coal additive in a nitrogen atmosphere and in a subcritical aqueous fluid at a temperature of 365°C and a pressure of 17 MPa. The coal additive consisted of an amorphous carbon phase forming a developed microporous structure. An analysis using scanning electron microscopy and adsorption porometry established that a vapor- air modification of the coal additive changes its surface relief and leads to the development of a micro- and mesopore structure. The intrapore space of the modified coal additive contains 38.6 vol % mesopores with a specific surface area of 172 m
2 /g. The final products of extra-heavy oil cracking with the proposed coal additive are characterized by an increase in the content of saturated and aromatic hydrocarbons, as well as by an almost complete absence of asphaltenes. The largest hydrocarbon yield was observed during extra-heavy oil cracking in a nitrogen atmosphere. In experiments, asphaltene conversion processes are observed due to the destruction of C–C, C–N, and C–O bonds with the formation of low-boiling compounds and high-carbon substances. The largest yield of aromatic hydrocarbons is observed during cracking in a subcritical aqueous fluid, with the yield of liquid products being reduced due to intensive gas formation. The hydrocarbon composition of gases is dominated by lower alkanes, which indicates the destruction of C–C bonds. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
43. Performance of Ni-Mo Sulfated Nanozirconia Catalyst for Conversion of Waste Cooking Oil into Biofuel via Hydrocracking Process
- Author
-
Arniz Hanifa, Wahyu Dita Saputri, Asma Nadia, Akhmad Syoufian, and Karna Wijaya
- Subjects
Cracking ,Materials science ,Cooking oil ,Mechanics of Materials ,Biofuel ,Mechanical Engineering ,Scientific method ,General Materials Science ,Condensed Matter Physics ,Pulp and paper industry ,Catalysis - Abstract
The synthesis of the Ni-Mo sulfated zirconia (NiMo-SZ) catalyst and its application to convert waste cooking oil into biofuel was successfully conducted. The synthesis process was started with a sulfation process on the zirconia oxide (ZrO2) using 0.5, 1.0, and 1.5 M sulfuric acid (H2SO4) through wet impregnation to obtain sulfated zirconia (SZ). Solid SZ with the highest total acidity value was calcined at temperature 500, 550, 600, 650, and 700 °C. Solid SZ calcined with the optimum temperature was treated with Ni and Mo metals at 1%, 2%, and 3% (w/w) through a hydrothermal method. Pure ZrO2, SZ, and 1, 2, and 3 NiMo-SZ catalysts were used in the hydrocracking of used cooking oil into biofuel. The results showed that the 1.5 M SZ catalyst calcined at 500 °C had the highest acidity value of 3.8137 mmol/g. The 3-NiMo-SZ catalyst had the best activity valuing at 80.54%, while 1-NiMo-SZ produced the best selectivity in producing gasoline fraction until 73.93%.
- Published
- 2021
44. Optimization of Bio-Hydrogenated Gasoline Production from Rice Bran Oil via Catalytic Hydrocracking over Pd/Al2O3 Catalyst
- Author
-
Wiphada Attaphaiboon, Sutasinee Neramittagapong, Arthit Neramittagapong, and Somnuk Theerakulpisut
- Subjects
Cracking ,General Energy ,Central composite design ,Biofuel ,Chemistry ,Rice bran oil ,Gasoline ,Pulp and paper industry ,Catalysis - Published
- 2021
45. A pubescence color gene enhances tolerance to cold-induced seed cracking in yellow soybean
- Author
-
Yoko Yamashita, Chika Suzuki, Mineo Senda, and Naoya Yamaguchi
- Subjects
seed cracking ,abiotic stress ,tolerance ,Abiotic stress ,food and beverages ,Plant Science ,yellow soybean ,Biology ,Cracking ,Horticulture ,gene pyramiding ,Genetics ,Agronomy and Crop Science ,Gene ,Research Paper - Abstract
In yellow soybean, severe cold weather causes seed cracking on the dorsal side. Yellow soybeans carry the I or ii allele of the I locus and have a yellow (I) or pigmented (ii) hilum. We previously isolated an additional allele, designated as Ic, of the I locus, and reported that yellow soybeans with the IcIc genotype may be tolerant to cold-induced seed cracking. The Ic allele by itself, however, does not confer high tolerance. The association of a pubescence color gene (T) with suppression of low-temperature-induced seed coat deterioration has been previously reported. In the present study, we tested whether T is effective for the suppression of cold-induced seed cracking using two pairs of near-isogenic lines for the T locus in the iiii or IcIc background. In both backgrounds, the cracked seed rate of the near-isogenic line with the TT genotype was significantly lower than that with the tt genotype, which indicates that T has an inhibitory effect on cold-induced seed cracking. Furthermore, we also showed that gene pyramiding of Ic and T can improve tolerance to cold-induced seed cracking. Our findings should aid the development of highly SC-tolerant cultivars in soybean breeding programs.
- Published
- 2021
46. Effect of Calcium Oxide Addition on Tar Formation During the Pyrolysis of Key Municipal Solid Waste (MSW) Components
- Author
-
Chen Chong, Xiaoyuan Zheng, Zhi Ying, and Bo Wang
- Subjects
Environmental Engineering ,Municipal solid waste ,Renewable Energy, Sustainability and the Environment ,Pulp (paper) ,0211 other engineering and technologies ,02 engineering and technology ,010501 environmental sciences ,engineering.material ,Polyethylene ,Pulp and paper industry ,01 natural sciences ,chemistry.chemical_compound ,Cracking ,chemistry ,engineering ,021108 energy ,Calcium oxide ,Waste Management and Disposal ,Pyrolysis ,Chemical composition ,0105 earth and related environmental sciences ,Syngas - Abstract
MSW pyrolysis/gasification is regarded as a promising technology allowing for energy and chemical recovery. The condensed tar in the syngas will cause problems in the downstream operations and lower its conversion efficiency. In this study, effects of calcium oxide (CaO) addition on tar formation during the pyrolysis of three key MSW components including bamboo, paper pulp and polyethylene (PE) were investigated using analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and a batch-type fixed bed reactor. The results from Py-GC/MS study agreed well with those from the pyrolysis in the fixed bed reactor, indicating that adding CaO reduced the tar yield and changed its chemical composition. However, the changes of the compounds in the tar were different among the pyrolysis of three MSW components. Taking the naphthalenes as an example, its content increased from paper pulp pyrolysis while it declined from bamboo and PE pyrolysis. Due to the rupture of ringed structures and tar cracking by CaO catalysis, the increase in H2 was observed. Compared with the pyrolysis of bamboo and paper pulp, higher yields of hydrocarbons C2 and C3 were achieved during the PE pyrolysis. The information about the tar formation derived from key MSW components can provide profound understanding of its generation from real MSW and favor the tar reduction or removal.
- Published
- 2018
47. Correlative HHV prediction from proximate and ultimate analysis of char obtained from co-cracking of residual fuel oil with plastics
- Author
-
Pamreishang Kasar and Md. Ahmaruzzaman
- Subjects
Polypropylene ,Cracking ,chemistry.chemical_compound ,Coefficient of determination ,chemistry ,General Chemical Engineering ,Energy density ,Context (language use) ,General Chemistry ,Fuel oil ,Char ,Proximate ,Pulp and paper industry - Abstract
It is imperative to know the energy content of the char to ascertain its application, which is environmentally friendly and efficient. In this context, the higher heating values (HHV) of the char resulting from the co-cracking of residual fuel oil (RFO) with various other waste plastics have been determined experimentally. Experimental results of the proximate and ultimate analysis of the char obtained from the co-cracking process were used to estimate the higher heating values (HHV) using eight different correlation models. The char obtained from the co-cracking of RFO and polypropylene (PPI) was found to have higher heating values (HHV) of 31.02 MJ/kg, while the HHV of Bakelite (BL) showed 23.56 MJ/kg. The best among the proximate correlations considered in this study resulted in the coefficient (R2) of 0.971, the average bias of −0.68%, and absolute error of 1.70%. The most relevant among the ultimate correlation models resulted in the coefficient of determination (R2) of 0.980, whereas the average and absolute bias errors were found to be −1.29% and 0.25%, respectively. The proximate and ultimate analysis of the chars reveals a direct interaction between the reactive species during the co-cracking of RFO with various types of plastic waste used in the study.
- Published
- 2021
48. Comparative Life Cycle Assessment of Asphalt Mixtures Using Composite Admixtures of Lignin and Glass Fibers
- Author
-
Jianxun Ma, Ahmed Khater, Mohamed Ghazy, Moustafa Abdelsalam, and Dong Luo
- Subjects
Technology ,Glass fiber ,Composite number ,Raw material ,Article ,chemistry.chemical_compound ,Lignin ,General Materials Science ,Life-cycle assessment ,Microscopy ,QC120-168.85 ,lignin fiber ,QH201-278.5 ,environmental impacts ,Pulp and paper industry ,Engineering (General). Civil engineering (General) ,TK1-9971 ,Cracking ,chemistry ,Descriptive and experimental mechanics ,Asphalt ,life cycle assessment (LCA) ,Environmental science ,Electrical engineering. Electronics. Nuclear engineering ,Ecotoxicity ,TA1-2040 ,composite mixture ,glass fiber - Abstract
Lignin and glass fiber were used as additives to improve the quality of road pavements and minimize moisture damage and cracking at low temperatures on asphalt pavement, according to a previous laboratory study. The aim of this paper is to make a significant contribution to the environmental assessment of the construction of road pavements using four types of asphalt mixtures based on the life cycle assessment (LCA) methodology according to the requirements of ISO 14040, considering the impact of raw material extraction, asphalt mixture manufacturing, transportation, and wearing surface construction. The results of the environmental assessment showed that all studied asphalt mixtures do not offer any improvement in all impact categories, and three modified asphalt mixtures have a slight negative effect in all impact categories. The composite mixture has the highest negative effect of the studied three modified asphalt mixtures in all categories except in the marine aquatic ecotoxicity potential category and freshwater aquatic ecotoxicity potential category, where the lignin modified asphalt mixture has the highest negative effect in these two categories but has the best environmental impacts on most of other impact categories. Furthermore, the negative effect caused by composite asphalt mixtures is minimal and thus can be used to improve the overall performance of asphalt pavement.
- Published
- 2021
49. Selective hydrogenation of light cycle oil for BTX and gasoline production purposes
- Author
-
Patricia Pérez-Romo, Georgina C. Laredo, Ricardo Agueda-Rangel, Alfonso García-López, and Eli Hazel Olmos-Cerda
- Subjects
Cracking ,020401 chemical engineering ,Light Cycle ,Chemistry ,General Chemical Engineering ,Production (economics) ,02 engineering and technology ,0204 chemical engineering ,Gasoline ,021001 nanoscience & nanotechnology ,0210 nano-technology ,Pulp and paper industry - Abstract
The study of the best experimental conditions and catalyst for the hydrogenation (HYD) of light cycle oil (LCO) for upgrading purposes was carried out. The objective was to examine the ability of two commercial hydrotreatment (HDT) catalysts for selective aromatic saturation. The effect of the hydrotreatment operation parameters (temperature, pressure, liquid hourly space velocity, H2/HC ratio) on the sulfur and nitrogen contents and in the saturation of aromatic hydrocarbons was also investigated. The goal was to obtain the highest conversion to mono-aromatic hydrocarbons from this di-aromatic (naphthalene derivatives) type feedstock, and at the same time to get reasonable hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) performance to avoid contaminant hydrocarbons for the next step (usually hydrocracking, HCK). An appropriate hydrotreated product with the highest concentration of mono-aromatic derivatives, a minimum reduction on the total aromatic content, and suitable decrements of sulfur and nitrogen compounds, was achieved using a cobalt-molybdenum supported on alumina catalyst, at 330 °C, 5.5 MPa, and a liquid hourly space velocity of 1.1 h−1. Additionally, the kinetics of the HDA was studied, assuming a lump characterization into tri-, di- and mono-aromatic and aliphatic hydrocarbons, pseudo-first-order reaction rates between these conversions, and thermal losses and diffusional resistances to be undetectable.
- Published
- 2021
50. Continuous Slurry Hydrocracking of Biobased Fast Pyrolysis Oil
- Author
-
Linda Sandström, Roger Molinder, Niklas Bergvall, and Ann Christine Johansson
- Subjects
General Chemical Engineering ,Energy Engineering and Power Technology ,Lignocellulosic biomass ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Pulp and paper industry ,Refinery ,Cracking ,chemistry.chemical_compound ,Fuel Technology ,020401 chemical engineering ,chemistry ,Pyrolysis oil ,Slurry ,Environmental science ,0204 chemical engineering ,0210 nano-technology ,Pyrolysis - Abstract
Co-refining of fast pyrolysis bio-oil together with fossil oil in existing refinery infrastructure is an attractive and cost-efficient route to conversion of lignocellulosic biomass to transportati...
- Published
- 2021
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