Search results for: rock hardness
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 1364

Search results for: rock hardness

464 Microstracture of Iranian Processed Cheese

Authors: R. Ezzati, M. Dezyani, H. Mirzaei

Abstract:

The effects of the concentration of trisodium citrate (TSC) emulsifying salt (0.25 to 2.75%) and holding time (0 to 20 min) on the textural, rheological, and microstructural properties of Iranian Processed Cheese Cheddar cheese were studied using a central composite rotatable design. The loss tangent parameter (from small amplitude oscillatory rheology), extent of flow, and melt area (from the Schreiber test) all indicated that the meltability of process cheese decreased with increased concentration of TSC and that holding time led to a slight reduction in meltability. Hardness increased as the concentration of TSC increased. Fluorescence micrographs indicated that the size of fat droplets decreased with an increase in the concentration of TSC and with longer holding times. Acid-base titration curves indicated that the buffering peak at pH 4.8, which is due to residual colloidal calcium phosphate, decreased as the concentration of TSC increased. The soluble phosphate content increased as concentration of TSC increased. However, the insoluble Ca decreased with increasing concentration of TSC. The results of this study suggest that TSC chelated Ca from colloidal calcium phosphate and dispersed casein; the citrate-Ca complex remained trapped within the process cheese matrix. Increasing the concentration of TSC helped to improve fat emulsification and casein dispersion during cooking, both of which probably helped to reinforce the structure of process cheese.

Keywords: Iranian processed cheese, cheddar cheese, emulsifying salt, rheology

Procedia PDF Downloads 443
463 Comparison of White Sauce Prepared from Native and Chemically Modified Corn and Pearl Millet Starches

Authors: Marium Shaikh, Tahira M. Ali, Abid Hasnain

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Physical and sensory properties of white sauces prepared from native and chemically modified corn and pearl millet starches were compared. Interestingly, no syneresis was observed in hydroxypropylated corn and pearl millet starch containing white sauce even after nine days of cold storage (4 °C), while other modifications also reduced the syneresis significantly in comparison to their native counterparts. White sauce containing succinylated corn starch showed least oil separation due to its greater emulsion stability. Light microscopy was used to visualize the size and shape of fat globules, and it was found that they were most homogenously distributed in succinylated and hydroxypropylated samples. Sensory results revealed that chemical modification of corn and pearl millet starch improved the consistency, thickness and overall acceptability of white sauces. Viscosity profiles showed that pasting parameters of native pearl millet starch are almost similar to native corn starch suggesting pearl millet starch as an alternative of corn starch. Also, white sauce prepared from modified pearl millet starch showed better cold storage stability in terms of various textural attributes like hardness, cohesiveness, chewiness, and springiness.

Keywords: corn starch, pearl millet, hydroxypropylation, succinylation, white sauce

Procedia PDF Downloads 285
462 Simultaneous Improvement of Wear Performance and Toughness of Ledeburitic Tool Steels by Sub-Zero Treatment

Authors: Peter Jurči, Jana Ptačinová, Mária Hudáková, Mária Dománková, Martin Kusý, Martin Sahul

Abstract:

The strength, hardness, and toughness (ductility) are in strong conflict for the metallic materials. The only possibility how to make their simultaneous improvement is to provide the microstructural refinement, by cold deformation, and subsequent recrystallization. However, application of this kind of treatment is impossible for high-carbon high-alloyed ledeburitic tool steels. Alternatively, it has been demonstrated over the last few years that sub-zero treatment induces some microstructural changes in these materials, which might favourably influence their complex of mechanical properties. Commercially available PM ledeburitic steel Vanadis 6 has been used for the current investigations. The paper demonstrates that sub-zero treatment induces clear refinement of the martensite, reduces the amount of retained austenite, enhances the population density of fine carbides, and makes alterations in microstructural development that take place during tempering. As a consequence, the steel manifests improved wear resistance at higher toughness and fracture toughness. Based on the obtained results, the key question “can the wear performance be improved by sub-zero treatment simultaneously with toughness” can be answered by “definitely yes”.

Keywords: ledeburitic tool steels, microstructure, sub-zero treatment, mechanical properties

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461 Jalovchat Gabbroic Intrusive of the Caucasus: Petrological Study, Geochemical Peculiarities and Formation Conditions

Authors: Giorgi Chichinadze, David Shengelia, Tamara Tsutsunava, Nikoloz Maisuradze, Giorgi Beridze

Abstract:

The Jalovchat intrusive is built up of hornblende gabbros, gabbro-norites and norites. Within the intrusive hornblende-bearing gabbro-pegmatites are widespread. That is a coarse-grained rock with gigantic hornblende crystals. By its unusual composition, the Jalovchat intrusive has no analogue in the Caucasus. However, petrologically and geochemically, the intrusive rocks were studied insufficiently. For comprehensive investigations, the authors applied appropriate methodologies: Microscopic study of thin sections, petro- and geochemical analyses of the samples and also different petrogenic, rare and rare earth elements diagrams and spidergrams. Analytical study established that the Jalovchat intrusive by its composition corresponds mainly to the mid-ocean ridge basalts and according to geodynamic type belongs to the subduction type. In general, it is an anomalous phenomenon, as in the rocks of such composition crystallization of hornblende and especially of its gigantic crystals is atypical. The authors believe that the water-rich magma reservoir, which was necessary for the crystallization of gigantic hornblende crystals, appeared as a result of melting of water-rich mid-ocean ridge basaltic rocks during the subduction process in Bajocian time.

Keywords: gabbro-pegmatite, intrusive, petrogenesis, petrogeochemistry, the Caucasus

Procedia PDF Downloads 209
460 Directional Solidification of Al–Cu–Mg Eutectic Alloy

Authors: Yusuf Kaygısız, Necmetti̇n Maraşlı

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Aluminum alloys are produced and used at various areas of industry and especially in the aerospace industry. The advantages of these alloys over traditional iron-based alloys are lightweight, corrosion resistance, and very good thermal and electrical conductivity. The aim of this work is to experimentally investigate the effect of growth rates on the eutectic spacings (λ), microhardness, tensile strength and electrical resistivity in Al–30wt.%Cu–6wt.%Mg eutectic alloy. Al–Cu–Mg eutectic alloy was directionally solidified at a constant temperature gradient (G=8.55 K/mm) with different growth rates, 9.43 to 173.3 µm/s by using a Bridgman-type furnace. The dependency of microstructure, microhardness, tensile strength and electrical resistivity for directionally solidified the Al-Cu-Mg eutectic alloy were investigated. Eutectic microstructure is consisting of regular Al2CuMg lamellar and Al2Cu rod phases with in the α (Al) solid solution matrix. The lamellar eutectic spacings were measured from transverse sections of the samples. It was found that the value of microstructures decrease with the increase the value the growth rates. The microhardness, tensile strength and electrical resistivity of the alloy also were measured from sample and relationships between them were experimentally analyzed by using regression analysis. According to present results, values tensile strength and electrical resistivity increase with increasing growth rates.

Keywords: directional solidification, aluminum alloys, microstructure, electrical properties, hardness test

Procedia PDF Downloads 294
459 Characterization of Nanostructured and Conventional TiAlN and AlCrN Coated ASTM-SA213-T-11 Boiler Steel

Authors: Vikas Chawla, Buta Singh Sidhu, Amita Rani, Amit Handa

Abstract:

The main objective of the present work is microstructural and mechanical characterization of the conventional and nanostructured TiAlN and AlCrN coatings deposited on T-11 boiler steel. In case of conventional coatings, Al-Cr and Ti-Al metallic powders were deposited using plasma spray process followed by gas nitriding of the surface which was done in the lab with optimized parameters after conducting several trials on plasma-sprayed coated specimens. The physical vapor deposition process (PAPVD) was employed for depositing nanostructured TiAlN and AlCrN coatings. The field emission scanning electron microscopy (FE-SEM) with energy dispersive X-ray analysis (EDAX) attachment, X-ray diffraction (XRD) analysis, atomic force microscopy (AFM) analysis and the X-Ray mapping analysis techniques have been used to study surface and cross-sectional morphology of the coatings. The surface roughness and micro-hardness were also measured. A good adhesion of the conventional thick TiAlN and AlCrN coatings was found. The coatings under study are recommended for the applications to super-heater and re-heater tubes of the boilers based upon the outcomes of the research work.

Keywords: nanostructure, physical vapour deposition, oxides, thin films, electron microscopy

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458 Low Resistivity Pay Identification in Carbonate Reservoirs of Yadavaran Oilfield

Authors: Mohammad Mardi

Abstract:

Generally, the resistivity is high in oil layer and low in water layer. Yet there are intervals of oil-bearing zones showing low resistivity, high porosity, and low resistance. In the typical example, well A (depth: 4341.5-4372.0m), both Spectral Gamma Ray (SGR) and Corrected Gamma Ray (CGR) are relatively low; porosity varies from 12-22%. Above 4360 meters, the reservoir shows the conventional positive difference between deep and shallow resistivity with high resistance; below 4360m, the reservoir shows a negative difference with low resistance, especially at depths of 4362.4 meters and 4371 meters, deep resistivity is only 2Ω.m, and the CAST-V imaging map shows that there are low resistance substances contained in the pores or matrix in the reservoirs of this interval. The rock slice analysis data shows that the pyrite volume is 2-3% in the interval 4369.08m-4371.55m. A comprehensive analysis on the volume of shale (Vsh), porosity, invasion features of resistivity, mud logging, and mineral volume indicates that the possible causes for the negative difference between deep and shallow resistivities with relatively low resistance are erosional pores, caves, micritic texture and the presence of pyrite. Full-bore Drill Stem Test (DST) verified 4991.09 bbl/d in this interval. To identify and thoroughly characterize low resistivity intervals coring, Nuclear Magnetic Resonance (NMR) logging and further geological evaluation are needed.

Keywords: low resistivity pay, carbonates petrophysics, microporosity, porosity

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457 Increasing Redness and Microbial Stability of Low Nitrite Chicken Sausage by Encapsulated Tomato Pomace Extract

Authors: Bung-Orn Hemung, Nachayut Chanshotigul, Koo Bok Chin

Abstract:

Tomato pomace (TP) is the waste from tomato processing plants and its utilization as food ingredient may provide sustainable industry by reducing waste. TP was extracted by ethanol using microwave-assisted method at 180W for 90s. The ethanol was evaporated out, and an extract was encapsulated with maltodextrin (1:10) by spray drying to obtain an encapsulated TP extract (ETPE). The redness (a value) of ETPE powder was 6.5±0.05, and it was used as natural ingredient in the low-nitrite chicken sausage. Chicken emulsion sausage was prepared at 25 mg/kg of nitrite for being control. Effect of ETPE (1.0%) was evaluated along with the reference (150 mg/kg of nitrite without ETPE). The redness (a value) of sausage with ETPE was found at 6.8±0.03, which was higher than those of reference and control, which were at 4.8±.022 and 5.1±0.15, respectively. However, hardness, expressible moisture content and cooking yield values were reduced slightly. During storage at 10 °C in the air packed condition for 1 week, changes in color, pH, redness, and thiobarbituric acid reactive substances value were not significantly different. However, total microbial count of sausage samples with ETPE was lower than control for a 1 log cycle, suggesting microbial stability. Therefore, the addition of ETPE could be an alternative strategy to utilize TP as a natural colorant and antimicrobial agent to extend the shelf life of low-nitrite chicken sausage.

Keywords: antimicrobial ingredient, chicken sausage, ethanolic extract, low-nitrite sausage, tomato pomace

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456 The Chromitites of the Collo Ultramafic Rocks (NE Algeria): Two Generations Evidenced From Petrological, Mineralogical and Isotopic Studies

Authors: Rabah Laouar, Yahia Boudra, Adel Satouh, Adrian Boyce

Abstract:

The ultramafic rocks of the Collo region crop out as « stratified » masses that cross-cut older metamorphic formation of the basement. These rocks are mainly peridotites and serpentinites. The peridotites are composed of olivine, orthopyroxene, clinopyroxene and spinel (chromite). The chemical composition of these lherzolites show a magnesian character with high MgO contents (34.4 to 37.5%), high Cr (0.14 to 0.27%), Ni (0.14 to 0.26%) and Co (34 to 133 ppm) and low CaO and Al₂O₃ (0.02 to 2.2 and 0.5 to 2.8 % respectively). They represent a residue (restite) of a mantle magmas partial melting. The chromite which represents about 2 to 3% of the rock is a ubiquitous mineral and shows two different generations: primary idiomorphic millimetric crystals and secondary very fine, xenomorphic and interstitial aggregates. The primary chromites are alumino-ferro-magnesian crystals. They show high Al₂O₃ (25.77% to 27.36%) and MgO (10.70% to 13.36%). Cr# (100*Cr/ (Al+Cr)) varies between 45 and 48, and Mg# (100*Mg/Mg+Fe₂+) varies between 49 and 59. On the other hand, the secondary interstitial grains are iron-rich chromites; they show low Al₂O₃ (4.67% to 9.54%) and MgO (4.60% to 4.65%). Cr# is relatively high (77 to 88) whereas Mg# show relatively low values, varying between 22 and 25. Oxygen isotopic composition of both types of chromites is consistent with their derivation from a mantle source (ð¹⁸O vary between +3.9 and +5.2‰), though a contribution of ¹⁶O-rich component to the secondary chromites is not ruled out.

Keywords: peridotites, serpentinites, chromite, partial melting, collo, Algeria

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455 Traditional Management Systems and the Conservation of Cultural and Natural Heritage: Multiple Case Studies in Zimbabwe

Authors: Nyasha Agnes Gurira, Petronella Katekwe

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Traditional management systems (TMS) are a vital source of knowledge for conserving cultural and natural heritage. TMS’s are renowned for their ability to preserve both tangible and intangible manifestations of heritage. They are a construct of the intricate relationship that exists between heritage and host communities, where communities are recognized as owners of heritage and so, set up management mechanisms to ensure its adequate conservation. Multiple heritage condition surveys were conducted to assess the effectiveness of using TMS in the conservation of both natural and cultural heritage. Surveys were done at Nharira Hills, Mahwemasimike, Dzimbahwe, Manjowe Rock art sites and Norumedzo forest which are heritage places in Zimbabwe. It assessed the state of conservation of the five case studies and assessed the role that host communities play in the management of these heritage places. It was revealed that TMS’s are effective in the conservation of natural heritage, however in relation to heritage forms with cultural manifestations, there are major disparities. These range from differences in appreciation and perception of value within communities leading to vandalism, over emphasis in the conservation of the intangible element as opposed to the tangible. This leaves the tangible element at risk. Despite these issues, TMS are a reliable knowledge base which enables more holistic conservation approaches for cultural and natural heritage.

Keywords: communities, cultural intangible, tangible heritage, traditional management systems, natural

Procedia PDF Downloads 559
454 Physicochemical and Bacteriological Assessment of Water Resources in Ughelli and Its Environs, Delta State Nigeria

Authors: M. O. Eyankware, D. O. Ufomata

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Groundwater samples were collected from Otovwodo-Ughelli and Environ with the aim of assessing groundwater quality of the area. Twenty (20) water samples from Boreholes (BH) (six) and Hand Dug Wells (HDW) (fourteen) were randomly sampled and were analysed for different physiochemical and bacteriological parameters. The following 16 parameters have been considered viz: pH, electrical conductivity, temperature, total hardness, total dissolved solids, dissolved oxygen, biological oxygen demand, phosphate, sulphate, chloride, nitrate, calcium, sodium, chloride, magnesium, and total suspended solids. On comparing the results against drinking quality standards laid by World Health Organization and Nigeria industrial standard, it was found that the water quality parameters were not above the (WHO, 2011 and NIS, 2007) permissible limit. Microbial analysis reveals the presence of coliform and E.coli in two hand-dug well (HDW7 and 13) and one borehole well (BH20). These contaminations are perhaps traceable to have originated from human activities (septic tanks, latrines, dumpsites) and have affected the quality of groundwater in Otovwodo-Ughelli. From the piper trilinear diagram, the dominant ionic species is alkali bicarbonate water type, with bicarbonate as the predominant ion (Na+ + K+)-HCO3.

Keywords: groundwater, surface water, Ughelli, Nigeria industrial standard, who standard

Procedia PDF Downloads 444
453 A Study on the Stabilization of the Swell Behavior of Basic Oxygen Furnace Slag by Using Geopolymer Technology

Authors: K. Y. Lin, W. H. Lee, T. W. Cheng, S. W. Huang

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Basic Oxygen Furnace (BOF) Slag is a by-product of iron making. It has great engineering properties, such as, high hardness and density, high compressive strength, low abrasion ratio, and can replace natural aggregate for building materials. However, the main problem for BOF slag is expansion, due to it contains free lime or free magnesium. The purpose of this study was to stabilize the BOF slag by using geopolymeric technology, hoping can prevent BOF slag expansion. Geopolymer processes contain a large amount of free silicon. These free silicon can react with free-lime or free magnesium oxide in BOF slag, and thus to form stable compound, therefore inhibit the expansion of the BOF slag. In this study for the successful preparation of geopolymer mortar with BOF slag, and their main properties are analyzed with regard to their use as building materials. Autoclave is used to study the volume stability of these geopolymer mortar. Finally, the compressive strength of geopolymer mortar with BOF slag can be reached 33MPa in 28 days. After autoclave testing, the volume expansion does not exceed 0.2%. Even after the autoclave test, the compressive strength can increase to 35MPa. According to the research results can be proved that using geopolymer technology for stabilizing BOF slag is very effective.

Keywords: BOF slag, autoclave test, geopolymer, swell behavior

Procedia PDF Downloads 136
452 The Influence of C Element on the Phase Transformation in Weldment of Complex Stainless Steels 2507/316/316L

Authors: Lin Dong-Yih, Yang S. M., Huang B. W., Lian J. A.

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Super duplex stainless steel has excellent mechanical properties and corrosion resistance. It becomes important structural material as its application has been extended to the fields such as renewable energy and the chemical industry because of its excellent properties. As examples are offshore wind power, solar cell machinery, and pipes in the chemical industry. The mechanical properties and corrosion resistance of super duplex stainless steel can be eliminated by welding due to the precipitation of the hard and brittle σ phase, which is rich of chromium, and molybdenum elements. This paper studies the influence of carbon element on the phase transformation of -ferrite and σ phase in 2507 super duplex stainless steel. The 2507 will be under argon gas protection welded with 316 and 316L extra low carbon stainless steel separately. The microstructural phases of stainless steels before and after welding, in fusion, heat affected zones, and base material will be studied via X-ray, OM, SEM, EPMA i.e. their quantity, size, distribution, and morphology. The influences of diffusion by carbon element will be compared according to the microstructures, hardness, and corrosion tests.

Keywords: complex stainless steel, welding, phase formation, carbon element, sigma phase, delta ferrite

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451 Effect on Physicochemical and Sensory Attributes of Bread Substituted with Different Levels of Matured Soursop (Anona muricata) Flour

Authors: Mardiana Ahamad Zabidi, Akmalluddin Md. Yunus

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Soursop (Anona muricata) is one of the underutilized tropical fruits containing nutrients, particularly dietary fibre and antioxidant properties that are beneficial to human health. This objective of this study is to investigate the feasibility of matured soursop pulp flour (SPF) to be substituted with high-protein wheat flour in bread. Bread formulation was substituted with different levels of SPF (0%, 5%, 10% and 15%). The effect on physicochemical properties and sensory attributes were evaluated. Higher substitution level of SPF resulted in significantly higher (p<0.05) fibre, protein and ash content, while fat and carbohydrate content reduced significantly (p<0.05). FESEM showed that the bread crumb surface of control and 5% SPF appeared to distribute evenly and coalesced by thin gluten film. However, higher SPF substitution level in bread formulation exhibited a deleterious effect by formation of discontinuous gluten network. For texture profile analysis, 5% SPF bread resulted in the lowest value of hardness. The score of sensory evaluation showed that 5% SPF bread received good acceptability and is comparable with control bread.

Keywords: soursop pulp flour, bread, physicochemical properties, sensory attributes, scanning electron microscopy (SEM)

Procedia PDF Downloads 322
450 Investigation on the Effect of Welding Parameters in Additive Friction Stir Welding of Glass Fiber Reinforced Polyamide 66 Composite

Authors: Nandhini Ravi, Muthukumaran Shanmugam

Abstract:

Metals are being replaced by thermoplastic polymer composites in automotive industries because of their low density, easiness to fabricate, low cost and good wear resistance. Complex polymer components consist of assemblies of smaller parts which can be joined by friction stir welding. This study deals with the additive friction stir welding of 15 wt.% glass fiber reinforced polyamide 66 composite which is a modified technique of the conventional friction stir welding by the addition of a filler plate for the heating of the composite work piece through the tool during the welding process. Welding at different combinations of tool rotational speed, travel speed and tool plunge depth was done after which the tensile strength of the respective experiments was determined. The maximum tensile strength obtained was 77 MPa which was 80% of the strength of the base material. The process parameters were optimized using the L9 orthogonal array and also the effect of individual welding parameter on the tensile strength was studied. The optimum parameter combination was determined with the help of ANOVA studies. The hardness of the welded joints was studied with the help of Shore Durometer which yielded the maximum of D 75.

Keywords: additive friction stir welding, polyamide 66, process parameters, thermoplastic polymer composite

Procedia PDF Downloads 159
449 Analyzing the Causes Behind Gas Turbine Blade Failure: A Comprehensive Case Study

Authors: Med. A. Djeridane, M. Ferhat, H. A. Benhorma, O. Bouledroua

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This research is dedicated to exploring the failure of a turbine blade within a gas transportation plant, with a primary focus on conducting a comprehensive examination through advanced metallurgical and mechanical analyses of the identified failed blade. Crafted from the nickel superalloy Inconel IN738LC, the turbine engine had accumulated approximately 61,000 operational hours before the blades failed, causing severe damage to the transportation plant and necessitating a prolonged shutdown. The investigative procedure commenced with an in-depth visual inspection of the blade surfaces, succeeded by fractography analysis of the fracture surfaces, microstructural investigations, chemical analysis, and hardness measurements. The findings unveiled distinctive fatigue marks on the fracture surface. Critical microstructural changes were identified as a consequence of the blade's operation at high temperatures. The investigation determined that the crack initiation resulted from coating damage at the leading edge, subsequently propagating through fatigue. Ultimately, due to a reduction in cross-sectional area, the fracture was completed. This comprehensive analysis sheds light on the intricate factors contributing to turbine blade failure and offers valuable insights for enhancing operational reliability in similar environments.

Keywords: gas turbine, blade failure, TCP phases, fatigue, quantitative analysis

Procedia PDF Downloads 61
448 Analytical Derivative: Importance on Environment and Water Analysis/Cycle

Authors: Adesoji Sodeinde

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Analytical derivatives has recently undergone an explosive growth in areas of separation techniques, likewise in detectability of certain compound/concentrated ions. The gloomy and depressing scenario which charaterized the application of analytical derivatives in areas of water analysis, water cycle and the environment should not be allowed to continue unabated. Due to technological advancement in various chemical/biochemical analysis separation techniques is widely used in areas of medical, forensic and to measure and assesses environment and social-economic impact of alternative control strategies. This technological improvement was dully established in the area of comparison between certain separation/detection techniques to bring about vital result in forensic[as Gas liquid chromatography reveals the evidence given in court of law during prosecution of drunk drivers]. The water quality analysis,pH and water temperature analysis can be performed in the field, the concentration of dissolved free amino-acid [DFAA] can also be detected through separation techniques. Some important derivatives/ions used in separation technique. Water analysis : Total water hardness [EDTA to determine ca and mg ions]. Gas liquid chromatography : innovative gas such as helium [He] or nitrogen [N] Water cycle : Animal bone charcoal,activated carbon and ultraviolet light [U.V light].

Keywords: analytical derivative, environment, water analysis, chemical/biochemical analysis

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447 Developing an Empirical Relationship to Predict Tensile Strength and Micro Hardness of Friction Stir Welded Aluminium Alloy Joints

Authors: Gurmeet Singh Cheema, Gurjinder Singh, Amardeep Singh Kang

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Aluminium alloy 6061 is a medium to high strength heat-treatable alloy which has very good corrosion resistance and very good weldability. Friction Stir Welding was developed and this technique has attracted considerable interest from the aerospace and automotive industries since it is able to produce defect free joints particularly for light metals i.e aluminum alloy and magnesium alloy. In the friction stir welding process, welding parameters such as tool rotational speed, welding speed and tool shoulder diameter play a major role in deciding the weld quality. In this research work, an attempt has been made to understand the effect of tool rotational speed, welding speed and tool shoulder diameter on friction stir welded AA6061 aluminium alloy joints. Statistical tool such as central composite design is used to develop the mathematical relationships. The mathematical model was developed to predict mechanical properties of friction stir welded aluminium alloy joints at the 95% confidence level.

Keywords: aluminium alloy, friction stir welding, central composite design, mathematical relationship

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446 Tribological Properties of Different Mass Ratio High Velocity Oxygen Fuel-Sprayed Al₂O₃-TiO₂ Coatings on Ti-6Al-4V Alloy

Authors: Mehmet Fahri Sarac, Gokcen Akgun

Abstract:

Ti–6Al–4V alloys are widely used in biomedical industries because of its attractive mechanical and physicochemical properties. However, they have poor wear resistance. High velocity oxygen fuel (HVOF) coatings were investigated as a way to improve the wear resistance of this alloy. In this paper, different mass ratio of Al₂O₃-TiO₂ powders (60/40, 87/13 and 97/3) was employed to enhance the tribological properties of Ti–6Al–4V. The tribological behavior was investigated by wear tests using ball-on-disc and pin-on-disc tribometer. The microstructures of the contact surfaces were determined by a scanning electron microscopy before and after the test to study the wear mechanism. Uncoated and coated surfaces after wear test are also subjected to micro-hardness tests. The tribological test results showed that the microhardness, friction and wear resistance of coated Ti-6Al-4V alloys increases by increasing TiO₂ content in the powder composite when other experimental conditions were constant. Finally, Al₂O₃-TiO₂ powder composites for the investigated conditions, both coating samples had satisfactory values of friction and wear resistance, and they could be suitable candidates for Ti–6Al–4V material.

Keywords: HVOF (High Velocity Oxygen Fuel), Al₂O₃-TiO₂, Ti-6Al-4V, tribology

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445 Study on Ratio of Binder Compounds in Thai Northern Style Sausages

Authors: Wipharat Saimo, Benjawan Thumthanaruk, Panida Banjongsinsiri, Nowwapan Noojuy

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Thai northern style sausage (sai-ou) is originally cuisine made of chili paste, pork, and lard. It always serves with curry paste, vegetable, and rice. The meat and lard ingredients used can be substituted by Shiitake mushroom (Lentinus edodes) and King oyster (Pleurotus eryngii) mushroom (50:50 w/w) which is suitable for all people, especially vegetarians. However, the texture of mushroom type sai-ou had no homogenous texture due to no adhesiveness property of mushroom. Therefore, this research aimed to study the ratio of hydrocolloids (konjac flour (0-100%), konjac gel (0-100%) and Citri-fi®100 FG (0-2%)) on the physicochemical properties mushroom type sai-ou. The mixture design was applied by using Minitab 16 software. Nine formula were designed for the test. The values of moisture content and water activity of nine formula were ranged from 66.25-72.17% and 0.96-0.97. The pH values were 5.44-5.89. The optimal ratio of konjac flour, konjac gel and Citri-fi®100 FG (74.75:24.75:0.5 (w/w)) yielded the highest texture profiles (hardness, springiness, cohesiveness, gumminess and chewiness) as well as color parameters (L*, a* and b*). Sensory results showed had higher acceptability scores in term of overall liking with the level of ‘like moderately’ (5.9 on 7 pointed scale). The mushroom type sai-ou sausage could be an alternative food for health-conscious consumers.

Keywords: Citri-fi® 100 FG, konjac flour, konjac gel, Thai northern style sausages

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444 Performance Evaluation of 3D Printed ZrO₂ Ceramic Components by Nanoparticle Jetting™

Authors: Shengping Zhong, Qimin Shi, Yaling Deng, Shoufeng Yang

Abstract:

Additive manufacturing has exerted a tremendous fascination on the development of the manufacturing and materials industry in the past three decades. Zirconia-based advanced ceramic has been poured substantial attention in the interest of structural and functional ceramics. As a novel material jetting process for selectively depositing nanoparticles, NanoParticle Jetting™ is capable of fabricating dense zirconia components with a high-detail surface, precisely controllable shrinkage, and remarkable mechanical properties. The presence of NPJ™ gave rise to a higher elevation regarding the printing process and printing accuracy. Emphasis is placed on the performance evaluation of NPJ™ printed ceramic components by which the physical, chemical, and mechanical properties are evaluated. The experimental results suggest the Y₂O₃-stabilized ZrO₂ boxes exhibit a high relative density of 99.5%, glossy surface of minimum 0.33 µm, general linear shrinkage factor of 17.47%, outstanding hardness and fracture toughness of 12.43±0.09 GPa and 7.52±0.34 MPa·m¹/², comparable flexural strength of 699±104 MPa, and dense and homogeneous grain distribution of microstructure. This innovative NanoParticle Jetting system manifests an overwhelming potential in dental, medical, and electronic applications.

Keywords: nanoparticle jetting, ZrO₂ ceramic, materials jetting, performance evaluation

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443 Two-Dimensional Seismic Response of Concrete Gravity Dams Including Base Sliding

Authors: Djamel Ouzandja, Boualem Tiliouine

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The safety evaluation of the concrete gravity dams subjected to seismic excitations is really very complex as the earthquake response of the concrete gravity dam depends upon its contraction joints with foundation soil. This paper presents the seismic response of concrete gravity dams considering friction contact and welded contact. Friction contact is provided using contact elements. Two-dimensional (2D) finite element model of Oued Fodda concrete gravity dam, located in Chlef at the west of Algeria, is used for this purpose. Linear and nonlinear analyses considering dam-foundation soil interaction are performed using ANSYS software. The reservoir water is modeled as added mass using the Westergaard approach. The Drucker-Prager model is preferred for dam and foundation rock in nonlinear analyses. The surface-to-surface contact elements based on the Coulomb's friction law are used to describe the friction. These contact elements use a target surface and a contact surface to form a contact pair. According to this study, the seismic analysis of concrete gravity dams including base sliding. When the friction contact is considered in joints, the base sliding displacement occurs along the dam-foundation soil contact interface. Besides, the base sliding may generally decrease the principal stresses in the dam.

Keywords: concrete gravity dam, dynamic soil-structure interaction, friction contact, sliding

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442 Seismic Hazard Analysis for a Multi Layer Fault System: Antalya (SW Turkey) Example

Authors: Nihat Dipova, Bulent Cangir

Abstract:

This article presents the results of probabilistic seismic hazard analysis (PSHA) for Antalya (SW Turkey). South west of Turkey is characterized by large earthquakes resulting from the continental collision between the African, Arabian and Eurasian plates and crustal faults. Earthquakes around the study area are grouped into two; crustal earthquakes (D=0-50 km) and subduction zone earthquakes (50-140 km). Maximum observed magnitude of subduction earthquakes is Mw=6.0. Maximum magnitude of crustal earthquakes is Mw=6.6. Sources for crustal earthquakes are faults which are related with Isparta Angle and Cyprus Arc tectonic structures. A new earthquake catalogue for Antalya, with unified moment magnitude scale has been prepared and seismicity of the area around Antalya city has been evaluated by defining ‘a’ and ‘b’ parameters of the Gutenberg-Richter recurrence relationship. The Standard Cornell-McGuire method has been used for hazard computation utilizing CRISIS2007 software. Attenuation relationships proposed by Chiou and Youngs (2008) has been used for 0-50 km earthquakes and Youngs et. al (1997) for deep subduction earthquakes. Finally, Seismic hazard map for peak horizontal acceleration on a uniform site condition of firm rock (average shear wave velocity of about 1130 m/s) at a hazard level of 10% probability of exceedance in 50 years has been prepared.

Keywords: Antalya, peak ground acceleration, seismic hazard assessment, subduction

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441 Mechanical Characterization and Metallography of Sintered Aluminium-Titanium Diboride Metal Matrix Composite

Authors: Sai Harshini Irigineni, Suresh Kumar Reddy Narala

Abstract:

The industrial applicability of aluminium metal matrix composites (AMMCs) has been rapidly growing due to their exceptional materials traits such as low weight, high strength, excellent thermal performance, and corrosion resistance. The increasing demand for AMMCs in automobile, aviation, aerospace and defence ventures has opened up windows of opportunity for the development of processing methods that facilitate low-cost production of AMMCs with superior properties. In the present work, owing to its economy, efficiency, and suitability, powder metallurgy (P/M) technique was employed to develop AMMCs with pure aluminium as matrix material and titanium diboride (TiB₂) as reinforcement. AMMC samples with different weight compositions (Al-0.1%TiB₂, Al-5%TiB₂, Al-10%TiB₂, and Al-15% TiB₂) were prepared through hot press compacting followed by traditional sintering. The developed AMMC was subjected to metallographic studies and mechanical characterization. Experimental evidences show significant improvement in mechanical properties such as tensile strength, hardness with increasing reinforcement content. The current study demonstrates the superiority of AMMCs over conventional metals and alloys and the results obtained may be of immense in material selection for different structural applications.

Keywords: AMMCs, mechanical characterization, powder metallurgy, TiB₂

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440 Hydrogen Embrittlement Properties of the Hot Stamped Carbon Steels

Authors: Mitsuhiro Okayasu, Lele Yang, Koji Shimotsu

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The effects of microstructural characteristics on the mechanical and hydrogen embrittlement properties of 1,800MPa grade hot stamping carbon steel were investigated experimentally. The tensile strength increased with increasing the hot stamping temperature until around 921°C, but that decreased with increasing the temperature in more than 921°C due to the increment of the size of lath martensite and prior austenite. With the hot stamping process, internal strain was slightly created in the sample, which led to the slight increment of the hardness value although no clear change of the microstructural formation was detected. Severity of hydrogen embrittlement was investigated using the hot stamped carbon steels after the immersion in a hydrogen gas, and that was directly attributed to the infiltration of the hydrogen into their grain boundaries. The high strength carbon steel with tiny lath martensite microstructure could make severe hydrogen brittleness as the hydrogen was strongly penetrated in the grain boundaries in the hydrogen gas for a month. Because of weak embrittlement for the as-received carbon (ferrite and pearlite), hydrogen embrittlement is caused by the high internal strain and high dislocation density. The hydrogen embrittlement for carbon steel is attributed to amount of the hydrogen immersed in-between grain boundaries, which is caused by the dislocation density and internal strain.

Keywords: hydrogen embrittlement, hot stamping process, carbon steel, mechanical property

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439 Geology, Geomorphology and Genesis of Andarokh Karstic Cave, North-East Iran

Authors: Mojtaba Heydarizad

Abstract:

Andarokh basin is one of the main karstic regions in Khorasan Razavi province NE Iran. This basin is part of Kopeh-Dagh mega zone extending from Caspian Sea in the east to northern Afghanistan in the west. This basin is covered by Mozdooran Formation, Ngr evaporative formation and quaternary alluvium deposits in descending order of age. Mozdooran carbonate formation is notably karstified. The main surface karstic features in Mozdooran formation are Groove karren, Cleft karren, Rain pit, Rill karren, Tritt karren, Kamintza, Domes, and Table karren. In addition to surface features, deep karstic feature Andarokh Cave also exists in the region. Studying Ca, Mg, Mn, Sr, Fe concentration and Sr/Mn ratio in Mozdooran formation samples with distance to main faults and joints system using PCA analyses demonstrates intense meteoric digenesis role in controlling carbonate rock geochemistry. The karst evaluation in Andarokh basin varies from early stages 'deep seated karst' in Mesozoic to mature karstic system 'Exhumed karst' in quaternary period. Andarokh cave (the main cave in Andarokh basin) is rudimentary branch work consists of three passages of A, B and C and two entrances Andarokh and Sky.

Keywords: Andarokh basin, Andarokh cave, geochemical analyses, karst evaluation

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438 Gypsum Composites with CDW as Raw Material

Authors: R. Santos Jiménez, A. San-Antonio-González, M. del Río Merino, M. González Cortina, C. Viñas Arrebola

Abstract:

On average, Europe generates around 890 million tons of construction and demolition waste (CDW) per year and only 50% of these CDW are recycled. This is far from the objectives determined in the European Directive for 2020 and aware of this situation, the European Countries are implementing national policies to prevent the waste that can be avoidable and to promote measures to increase recycling and recovering. In Spain, one of these measures has been the development of a CDW recycling guide for the manufacture of mortar, concrete, bricks and lightweight aggregates. However, there is still not enough information on the possibility of incorporating CDW materials in the manufacture of gypsum products. In view of the foregoing, the Universidad Politécnica de Madrid is creating a database with information on the possibility of incorporating CDW materials in the manufacture of gypsum products. The objective of this study is to improve this database by analysing the feasibility of incorporating two different CDW in a gypsum matrix: ceramic waste bricks (perforated brick and double hollow brick), and extruded polystyrene (XPS) waste. Results show that it is possible to incorporate up to 25% of ceramic waste and 4% of XPS waste over the weight of gypsum in a gypsum matrix. Furhtermore, with the addition of ceramic waste an 8% of surface hardness increase and a 25% of capillary water absorption reduction can be obtained. On the other hand, with the addition of XPS, a 26% reduction of density and a 37% improvement of thermal conductivity can be obtained.

Keywords: CDW, waste materials, ceramic waste, XPS, construction materials, gypsum

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437 Analytical Solutions for Tunnel Collapse Mechanisms in Circular Cross-Section Tunnels under Seepage and Seismic Forces

Authors: Zhenyu Yang, Qiunan Chen, Xiaocheng Huang

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Reliable prediction of tunnel collapse remains a prominent challenge in the field of civil engineering. In this study, leveraging the nonlinear Hoek-Brown failure criterion and the upper-bound theorem, an analytical solution for the collapse surface of shallowly buried circular tunnels was derived, taking into account the coupled effects of surface loads and pore water pressures. Initially, surface loads and pore water pressures were introduced as external force factors, equating the energy dissipation rate to the external force, yielding our objective function. Subsequently, the variational method was employed for optimization, and the outcomes were juxtaposed with previous research findings. Furthermore, we utilized the deduced equation set to systematically analyze the influence of various rock mass parameters on collapse shape and extent. To validate our analytical solutions, a comparison with prior studies was executed. The corroboration underscored the efficacy of our proposed methodology, offering invaluable insights for collapse risk assessment in practical engineering applications.

Keywords: tunnel roof stability, analytical solution, hoek–brown failure criterion, limit analysis

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436 Impact of Activated Carbon and Magnetic Field in Slow Sand Filter on Water Purification for Rural Dwellers

Authors: Baiyeri R. M, Oloriegbe Y. A., Saad A. O., Yusuf, K. O.

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Most farmers that produce food crops in Nigeria live in rural areas where potable water is not available. The farmers in some areas have problem of water borne diseases which could affect their health and could lead to death. This study was conducted to determine the impact of incorporating Granular Activated Carbon(GAC) and Magnetic Field(MF) in Slow Sand Filter(SSF) on the purification of water for rural dwellers. The SSF was developed using PVC pipe with diameter 152.4 mm and 1100 mm long, with layers of fine sand with size 0.25 mm and 350 mm depth, followed by GAC 10 mm size and 100 mm depth, fine sand 0.25mm with 500 mm depth and gravel grain size 10-14 mm and 100 mm depth. The SSF was kept moist for 21 days for biofilm layer (schmutzdecke) to fully develop, which is essential for trapping bacteria. Two SSFs fabricated consist of SSF+GAC as Filter 1, SSF+GAC+MF as Filter 2 and Control (Raw water without passing through filter. Water samples were collected from the filter and analyzed. The flow rate of Filter was 25 litres/h Total bacteria counts(TBC) for Filter 1 and Filter 2 and control were 2.4, 4.6 and 8.1 cfu/mg, respectively. Total coliform count for Filter 1 and Filter 2 and control were 1.7, 3.0 and 6.4 cfu/100mL, respectively. The filters reduced water hardness, turbidity, lead, copper, electrical conductivity and TBC by 53.13-73.44% but increased pH from 5.8 to 7.1-7.3. SSF is recommended for water purification in the rural areas.

Keywords: magnetised water, sow sand filter, portable water, activated carbon

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435 Characteristics and Key Exploration Directions of Gold Deposits in China

Authors: Bin Wang, Yong Xu, Honggang Qu, Rongmei Liu, Zhenji Gao

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Based on the geodynamic environment, basic geological characteristics of minerals and so on, gold deposits in China are divided into 11 categories, of which tectonic fracture altered rock, mid-intrudes and contact zone, micro-fine disseminated and continental volcanic types are the main prospecting kinds. The metallogenic age of gold deposits in China is dominated by the Mesozoic and Cenozoic. According to the geotectonic units, geological evolution, geological conditions, spatial distribution, gold deposits types, metallogenic factors etc., 42 gold concentration areas are initially determined and have a concentrated distribution feature. On the basis of the gold exploration density, gold concentration areas are divided into high, medium and low level areas. High ones are mainly distributed in the central and eastern regions. 93.04% of the gold exploration drillings are within 500 meters, but there are some problems, such as less and shallower of drilling verification etc.. The paper discusses the resource potentials of gold deposits and proposes the future prospecting directions and suggestions. The deep and periphery of old mines in the central and eastern regions and western area, especially in Xinjiang and Qinghai, will be the future key prospecting one and have huge potential gold reserves. If the exploration depth is extended to 2,000 meters shallow, the gold resources will double.

Keywords: gold deposits, gold deposits types, gold concentration areas, prospecting, resource potentiality

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