Journal articles on the topic 'Bar mix'
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McLennan, S. R., J. M. Campbell, C. H. Pham, K. A. Chandra, S. P. Quigley, and D. P. Poppi. "Responses to various protein and energy supplements by steers fed low-quality tropical hay. 2. Effect of stage of maturity of steers." Animal Production Science 57, no. 3 (2017): 489. http://dx.doi.org/10.1071/an15660.
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Dose response curves to various supplements were established in two pen-feeding experiments (Exp1 and Exp2) with Bos indicus crossbred steers of two age groups (Young, 10–12 months; Old, 33–36 months) fed low-quality tropical grass hays ad libitum. Diets included supplements based on (Exp1) cottonseed meal (CSM; intake (as fed) 0–10 g/kg liveweight (W).day) and a barley mix (Bar; 0–20 g/kg W.day) and (Exp2) a molasses mix (MUP) and a Bar mix, both fed at 0–20 g/kg W.day. Urea was provided with the Bar mixes and urea/copra meal with the MUP mix. Growth rates of Young steers increased linearly with Bar and MUP supplements but asymptotically with CSM whereas those of Old steers increased asymptotically with all supplement types. With supplement intake expressed on a liveweight basis (g/kg W.day), responses were greater for both steer age groups with CSM compared with Bar (Young, P < 0.001; Old, P < 0.01) and Bar compared with MUP treatments (Young, P < 0.01; Old, P < 0.05). Furthermore, Old steers outperformed their Young counterparts with both CSM (P < 0.05) and Bar (P < 0.001) supplements fed in Exp1 and with Bar and MUP supplements (P < 0.01) fed in Exp2. When supplement intake was expressed in absolute terms (kg/day), growth responses were not different between age groups for different supplements except that Old steers had a higher daily W gain on Bar than their Young counterparts (P < 0.05). Intake of hay (W-corrected) was higher for Young compared with Old steers without supplement but was variably reduced for both steer groups with increasing supplement intake. The results of these experiments have implications for supplement formulation for steers at different stages of maturity grazing low-quality forages.
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Daukšys, Mindaugas, Gintautas Skripkiūnas, Audrius Grinys, and Marija Vaičienė. "THE INFLUENCE OF THE SODIUM SILICATE ADMIXTURE ON THE PUMPED CONCRETE FLOWABILITY IN PIPELINES / NATRIO SILIKATO TIRPALO PRIEDO POVEIKIS SIURBLIAIS TRANSPORTUOJAMO BETONO MIŠINIO TEKAMUMUI VAMZDŽIAIS." Engineering Structures and Technologies 5, no. 1 (April 9, 2013): 20–29. http://dx.doi.org/10.3846/2029882x.2013.777019.
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In the research experimental studies of the effect sodium silicate solution (NST) and plasticizer admixtures have on concrete mixture pipe flow velocity and capacity during of the transportation of mixtures with the “S”-type valve concrete pump with two pistons where carried out. The filling time of 0.406 m3 volume foundation blocks forms of concrete mixture at different concrete mix pump supply pressures (25.5 and 68.0 bar) was measured. It was found that the addition to the mixture of NST 0.5% by weight of cement with superplasticizer based on polycarboxylic ethers, increases the flow rate of the mixture in the pipeline, and performance with a lower concrete mix pump supply pressure. With 0.5% NST of the cement mass with lignosulphonate plasticizer and reduced amount of cement in concrete mix, the flowability in pipeline with a low concrete mix pump delivery pressure (25.5 bar) is worse. With 0.5% NST of the cement mass with lignosulphonate plasticizer, using only 0/4 fraction sand, concrete mix transportation in mixture pipeline at low concrete mix pump delivery pressure (25.5 bar) is stopped. When the pump mix feed pressure is increased up to 68 bar, the mixture flows through the pipeline again. The investigation has shown that sodium silicate solution admixture interaction together with different chemical compositions plasticizers affects the mixture flowability in pipes. Santrauka Atliekant eksperimentinius tyrimus nustatytas natrio silikato tirpalo (NST) ir plastiklių poveikis betono mišinio tekėjimo vamzdžiu greičiui, našumui, transportuojant mišinius dviejų stūmoklių su S tipo vožtuvu betono siurbliu. Tyrimo metu matuotas 0,406 m3 tūrio pamatų blokų formų užpildymo betono mišiniu laikas, esant skirtingam betono siurblio mišinio tiekimo slėgiui – 25,5 ir 68,0 bar. Nustatyta, kad įmaišius į mišinį NST priedą 0,5% cemento masės kartu su superplastikliu polikarboksilo eterių pagrindu, pasiektas didesnis mišinio tekėjimo greitis vamzdynu ir gautas didesnis našumas esant mažesniam betono siurblio mišinio tiekimo slėgiui. Įmaišius į mišinį NST priedą 0,5% cemento masės kartu su plastikliu lignosulfonatų pagrindu ir sumažinus cemento kiekį mišinyje, betono mišinys blogai teka vamzdynu, kai betono siurblio mišinio tiekimo slėgis yra mažas – 25,5 bar. Įmaišius į mišinį NST priedą 0,5% cemento masės kartu su plastikliu lignosulfonatų pagrindu ir smulkiuoju užpildu naudojant tik 0/4 frakcijos smėlį, betono mišinys iš viso neteka mišinio transportavimo vamzdynu, esant mažam betono siurblio mišinio tiekimo slėgiui (25,5 bar). Padidinus siurblio mišinio tiekimo slėgį iki 68 bar, mišinys vėl pradeda tekėti mišinio transportavimo vamzdynu. Tyrimai parodė, kad natrio silikato tirpalo priedo sąveika su skirtingos cheminės sudėties plastikliu turi įtakos mišinio tekamumui vamzdžiais.
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Caroline, Etty, Imam Santoso, and Panji Deoranto. "PENGARUH MARKETING MIX (7P) DAN PERILAKU KONSUMEN TERHADAP KEPUTUSAN PEMBELIAN PRODUK HEALTHY FOOD BAR DI MALANG." Jurnal Manajemen Pemasaran 15, no. 1 (April 8, 2021): 10–19. http://dx.doi.org/10.9744/pemasaran.15.1.10-19.
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Abstrak: Peningkatan aktivitas dan pendapatan penduduk, mendorong diperlukannya makanan yang praktis, mudah, cepat cara penyajiannya serta bergizi. Healthy Food Bar (HFB) merupakan produk yang mempertimbangkan nilai gizi yang tinggi dan praktis. Tujuan penelitian ini untuk mengetahui pengaruh secara simultan dan parsial variabel dalam marketing mix (atribut produk, harga, saluran distribusi, promosi, orang, proses, lingkungan fisik) serta dalam perilaku konsumen (faktor lingkungan, individu, psikologis) terhadap keputusan pembelian HFB. Hasil penelitian dari 100 responden menunjukan variabel marketing mix (produk, harga, saluran distribusi, promosi, orang, proses, lingkungan fisik) dan perilaku konsumen (faktor lingkungan, individu, psikologis) secara simultan berpengaruh signifikan terhadap keputusan pembelian produk HFB. Secara parsial variabel marketing mix (produk, harga, saluran distribusi, promosi, orang, proses) dan variabel perilaku konsumen (faktor lingkungan, individu, psikologis) berpengaruh signifikan sedangkan variabel lingkungn fisik berpengaruh tidak signifikan terhadap keputusan pembelian produk HFB. Kata kunci : Healthy Food Bar, Marketing Mix, Perilaku Konsumen, Keputusan Pembelian, Regresi Linier Berganda Abstract: The improvement of activity and income the citizen need the practical, easy, fast, and nutritious foods. Healthy Food Bar ( HFB ) is a product that is considered a high nutritional value and practical. The purpose of this study was to determine the effect of variables simultaneously and partially in the marketing mix ( product attributes , pricing, distribution channels , promotion , people , process , physical environment ) as well as in consumer behavior ( environmental factors , individual , psychological ) to the purchasing decision HFB . The results of the study of 100 respondents showed variable marketing mix ( product , price , distribution channels , promotion , people , process , physical environment ) and consumer behavior ( environmental factors , individual , psychological ) simultaneously significant effect on product purchasing decisions HFB . In partial marketing mix ( product , price , distribution channels , promotion , people , process ) and consumer behavior variables ( environmental factors , individual , psychological ) significantly while the variable physical lingkungn insignificant effect on product purchasing decisions HFB . Keywords: Healthy Food Bar, Marketing Mix, Consumer Behaviour, Purchasing Decision, Multiple Linear Regression
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Guillochon, Mathilde, and David S. Rowlands. "Solid, Gel, and Liquid Carbohydrate Format Effects on Gut Comfort and Performance." International Journal of Sport Nutrition and Exercise Metabolism 27, no. 3 (June 2017): 247–54. http://dx.doi.org/10.1123/ijsnem.2016-0211.
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Carbohydrate sports drinks produce worthwhile benefits to endurance performance compared with noncaloric controls. However, athletes now consume carbohydrate in a range of formats, including gels and bars, but the comparable performance outcomes are unknown. Therefore, the aim of this study was to establish the relative effects of drink, gel, bar, and mixed carbohydrate formats on intense cycling performance. In a treatmentapparent randomized crossover design, 12 well-trained male cyclists completed 4 trials comprising a 140-min race simulation, followed by a double-blind slow-ramp to exhaustion (0.333 W·s-1). Carbohydrate comprising fructose and maltodextrin was ingested every 20 min via commercial drink, gel, bar, or mix of all 3, providing 80 g carbohydrate·h-1. Fluid ingestion was 705 ml·h-1. Exertion, fatigue, and gastrointestinal discomfort were measured with VAS. Performance peak power (SD) was 370 (41), 376 (37), 362 (51) and 368 W (54) for drink, gels, bars, and mix respectively. The reduction in power (-3.9%; 90%CI ±4.3) following bar ingestion vs. gel was likely substantial (likelihood harm 81.2%; benefit 0.8%), but no clear differences between drinks, gels, and the mix were evident. Bars also produced small-moderate standardized increases in nausea, stomach fullness, abdominal cramps, and perceived exertion, relative to gels (likelihood harm 95–99.5%; benefit <0.01%) and drink (75–95%; <0.01%); mix also increased nausea relative to gels (95%; <0.01%). Relative to a gel, carbohydrate bar ingestion reduced peak power, gut comfort, and ease of exertion; furthermore, no clear difference relative to drink suggests bars alone are the less favorable exogenous-carbohydrate energy source for intense endurance performance.
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Enos, Gary. "Bar settings offer dangerous mix during height of COVID‐19 crisis." Alcoholism & Drug Abuse Weekly 32, no. 27 (July 10, 2020): 1–8. http://dx.doi.org/10.1002/adaw.32771.
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Ismail, Sallehan, Mohamad Asri Abd Hamid, and Zaiton Yaacob. "Static and Dynamic Behaviors of Fibre Reinforced Recycled Aggregate Mortar." Key Engineering Materials 882 (April 2021): 237–46. http://dx.doi.org/10.4028/www.scientific.net/kem.882.237.
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This study aims to explore the inclusion of microfibre in fine recycled aggregate (FRA) mortars under dynamic impact load. A 12-mm-diameter Split Hopkinson Pressure Bar (SHPB) was employed to test the impact of a recycled mortar with a single and hybrid fibre system and to determine potential improvements in its dynamic mechanical properties. In recycled mortar production, two microfibres with different sizes and types, namely, polypropylene and nylon, were added whilst keeping the amount of microfibres at a volumetrical fraction of 0.6%. An impact loading test was conducted by using the striking bar of SHPB at impact speeds of 2, 4 and 6 m/s. The effects of fibre on failure mode, tensile curve, compressive strength and dynamic increase factor (DIF) were then analysed. Experimental findings show that the improved mortar fibre mix has superior quasi-static and dynamic compression power compared with the reference mortar mix. Meanwhile, compared with the single fibre mix, the hybrid fibre mix is more effective in enhancing the dynamic compressive ability of the recycled mortar. The recycled-hybrid-fibre-enhanced mortar showed lower DIF values compared with the reference mortar, and the inclusion of fibre reinforcement can reduce the fragmentation of the recycled mortar mix after being subjected to impact.
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Rahim, Jamilah Abd, Siti Hawa Hamzah, and Mohd Saman Hamidah. "Bonding Strength of Expanded Polystyrene (EPS) Beads Enhanced with Steel Fiber in Reinforced Lightweight Concrete (LWC)." Applied Mechanics and Materials 661 (October 2014): 100–105. http://dx.doi.org/10.4028/www.scientific.net/amm.661.100.
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Lightweight concrete (LWC) is one of the favourable concrete to be used as it has low density with acceptable high strength, high durability, and toughness. In order to produce LWC, it is required special material such as expanded polystyrene (EPS) beads and steel fiber to be added into the design mix concrete. As known, EPS beads have zero strength. Meanwhile, the significant of steel fiber is to reduce micro and macro crack propagation. Therefore, pull out test were carried out to measure the bond strength between reinforcement bar and three series of concrete mix design which are normal concrete, EPS-LWC and EPS-LWC enhanced with steel fiber. Concrete adhesion and bearing deformation of reinforcing bar against the concrete are the two main mechanisms that influence the strength of bond in the steel reinforced concrete. Deformation will increase when the bonding stress increase. Normal concrete series shows the higher average bonding stress which is 531.22 kPa compared to others series concrete mix. Meanwhile, bonding stress of EPS-LWC mix is 174.54 kPa which is higher than EPS-LWC enhanced with steel fiber mix. Even though the present of the steel fibre can increase the strength of the LWC, but it effects to the bonding strength between reinforcement steel rod and concrete. There are two improtant factor in bonding determination which are volume fraction and aspect ratio of the steel fiber. Segregation will increase when the aspect ratio of steel fiber increased. Besides, the workability becomes low. This present study used types of hooked end steel fiber with 60 mm length and aspected ratio is 0.75. While the size of the cylindrical is 300 mm x 150 mm. The position of the steel fiber in the specimens is too compact and presenting the air voids. Consequently weaken the bonding strength between concrete and reinforcement bar.
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Putra, Ryan Vernando, Muhartini Salim, and Sularsih Anggarawati. "OPINION LEADERSHIP MEMODERASI eWOM INTENTION (STUDI PADA BOMBARU BAR DAN RESTO BENGKULU, INDONESIA)." MIX JURNAL ILMIAH MANAJEMEN 10, no. 2 (May 27, 2020): 165. http://dx.doi.org/10.22441/mix.2020.v10i2.002.
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Abstract. The purpose of this study was to examine the influence of Self-Relevant Value, Quality Value and Perceived Informational Utility on Electronic Word-Of-Mouth Intention moderated by Opinion Leadership in Bombaru Bars and Restaurant Bengkulu, Indonesia consumers. The respondents of this study were 17-45 years old. Respondent data were collected by the survey questionnaire provided. After adopting the listwise deletion method through Mahalanobis Distance on SEM-AMOS, 133 questionnaires that could be used were available for analysis. Data analysis used Confirmatory Factor Analysis (CFA), assessment of normality, and regression weights. The Result indicate that (1) Self-relevant Value has a positif effect on eWOM Intention; (2) Quality Value has a positif effect on eWOM Intention; (3) Perceived Informational Utility has a postif effect on eWOM Intention; (4) Opinion Leadership moderates the influence of Self-relevant Value on eWOM Intention; (5) Opinion Leadership moderates the influence of Quality Value on eWOM Intention; (6) Opinion Leadership moderates the influence of Perceived Informational Utility on eWOM Intention.Keyword: eWOM Intention, Opinion Leadership, Perceived Informational Utility, Quality Value, and Self-relevant Value.
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SUZUKI, M. S., R. O. FIGUEIREDO, S. C. CASTRO, C. F. SILVA, E. A. PEREIRA, J. A. SILVA, and G. T. ARAGON. "Sand bar opening in a coastal lagoon (Iquipari) in the northern region of Rio de Janeiro State: hydrological and hydrochemical changes." Brazilian Journal of Biology 62, no. 1 (February 2002): 51–62. http://dx.doi.org/10.1590/s1519-69842002000100007.
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The aim of this paper was to verify hydrological and hydrochemical changes in the Iquiparí Lagoon water column, during three months, as related to an artificial sand bar opening. A drastic reduction in water volume occurred 28 hours after the sand bar opening, exposing the bottom sediment. This was densely colonized by submerged aquatic plants, which were dominant in the ecosystem metabolism, specially near the sand bar. An increase in salinity values, and dissolved and total nutrient concentrations, was observed during the sand bar opening period. In contrast, chlorophyll a concentration decreased. These changes were associated with: 1) mix of remained brackish and marine waters; 2) nutrient release from sediments by physical processes; and 3) submerged plant death. After the sand bar closure, lagoon metabolism was completely regulated by a dense phytoplankton community. We observed that the sand bar opening resulted in an extensile replacement of the lagoon's water and a change in the community mainly responsible for the ecosystem metabolism.
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Khojah, Ebtihal Yaqoob, Ahmed Noah Badr, Dalia Amin Mohamed, and Adel Gabr Abdel-Razek. "Bioactives of Pomegranate By-Products and Barley Malt Grass Engage in Cereal Composite Bar to Achieve Antimycotic and Anti-Aflatoxigenic Attributes." Foods 11, no. 1 (January 4, 2022): 119. http://dx.doi.org/10.3390/foods11010119.
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Food is the source from where a person obtains the body’s daily requirements. People’s current daily habits force them to consume fast food, which is known for its poor nutritional and safety features. So, it is urgent to provide a suitable substitution product to solve this issue. The present investigation aimed to produce a bar with a dual function: nutritional and long shelf life. Two materials were chosen to support the bar manufacturing regarding their bioactive contents, barley malt grass (BMG) and pomegranate byproducts (PBD). Chemical composition, antioxidant, and antimicrobial potency were measured. Β-carotene, vitamin C, and tocopherol were determined using HPLC apparatus. Extracts’ bio-safety against cell lines was determined, besides their enhancement against cell-death factors. Simulation experiments were designed to evaluate extracts’ impact to extend bar shelf life. Data represented the richness of essential minerals and fibers. Results of the FTIR reflected the existence of various active groups in the contents. Phenolic fractions of PBD are distinctive for their content of ellagic (39.21 ± 5.42 mg/kg), ferulic acid fractions (31.28 ± 4.07 mg/kg) which is a known with antifungal activity. Extracts and their mix (1:1) represented inhibition zone diameters that reach 15.1 ± 1.66 mm for bacteria and 23.81 ± 1.41 mm for fungi. Extracts were shown to have better safety against the cell line strain of hepatic HL-7702, with an elevation of a harmful dose of aflatoxin (IC50 304.5 µg/mL for PBD, IC50 381 µg/mL for BMG). Sensory evaluation of fortified bars reflected a preferable application of mix (1:1) due to color attributes and panelist evaluations, the same result recorded for simulation studies. The experiment recommended applying a mix (1:1) of BMG: PBD in addition to their extracts (200 mg/kg dough) for functional bar manufacturing with antifungal properties.
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Radziszewski, Piotr, Wioletta Jackiewicz-Rek, Michał Sarnowski, and Marek Urbański. "Fortification of Damaged Asphalt Pavements with Cement Concrete Slabs Reinforced with Next-Gen Bars – Part I: Laboratory Study." Archives of Civil Engineering 64, no. 3 (September 1, 2018): 67–80. http://dx.doi.org/10.2478/ace-2018-0030.
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AbstractOver the course of operation, asphalt road pavements are subjected to damage from car traffic loads and environmental factors. One of the possible methods of strengthening damaged asphalt pavements may be the application of an additional rigid layer in the form of a cement concrete slab with continuous reinforcement.This paper presents a material-technological and structural solution for composite pavement where a cement concrete slab with continuous HFRP bar reinforcement is used for strengthening. Based on laboratory tests, the serviceability of composite bar reinforcement of rigid pavement slabs was shown. A design for strengthening asphalt pavement with a concrete slab with steel bar and corresponding HFRP bar reinforcement was developed. The composition of a pavement cement concrete mix was designed, and experimental sections were formed. Based on laboratory tests of samples collected from the surfaces of experimental sections and the diagnostic tests carried out in “in situ” conditions, the authors will try, in the nearest future (Part II: In situ observations and tests), to confirm the effectiveness of strengthening asphalt pavements with cement concrete slabs with HFRP components.
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Bangwar, D. K., M. A. Soomro, N. A. Laghari, M. A. Soomro, and A. A. Buriro. "Improving the Bond Strength of Rice Husk Ash Concrete by Incorporating Polymer: A New Approach." Engineering, Technology & Applied Science Research 8, no. 1 (February 20, 2018): 2595–97. http://dx.doi.org/10.48084/etasr.1791.
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This paper gives an insight of how to improve the bond strength of cement in which concrete is replaced with rice husk ash. A concrete mix was prepared and was used in different types of mixes i.e. Control Mix, 10% cement substituted concrete with rice husk ash and polymer modified concrete by incorporation different dosages of polymer in the 10% cement substituted concrete. A bar of 12mm diameter, 300mm in length was placed in the center of the cylindrical specimens for pull out test. It was observed that the bond strength between concrete and steel decreases with the replacement of cement with ash, conversely the bond strength improves with the addition of polymer dosages.
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NAGY, Elena Mihaela, Constantin COȚA, Nicolae CIOICA, Zoltan GYORGY, Lucian FECHETE-TUTUNARU, Adina GHIRIŞAN, and Vasile MICLĂUŞ. "Researches Regarding a Protein Hydrolysate Used as Adjuvant in Fertilization Process." Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Agriculture 76, no. 2 (November 18, 2019): 78. http://dx.doi.org/10.15835/buasvmcn-agr:2018.0035.
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Within the paper the results of conducted researches in order to obtain a protein hydrolysate from wool waste as raw material are presented. The experiments were conducted in two variants: a) alkaline hydrolyse using potassium hydroxide, a mix of potassium hydroxide with urea and a mix of potassium hydroxide with sodium hydroxide as well as b) acidic hydrolyse with sulfuric acid or a mix of sufuric acid with phosphoric acid in different proportions. The parameters intervals used were: pH 0,5-2,5 for acidic hydrolyse and pH 9,5-13,5 for the alkalinic one; temperatures between 120-150 °C and pressures between 1,4-4,6 bar. Acid hydrolysis is favored by the high proportion of sulfuric acid, phosphoric acid, a low pH and from high temperature and pressure. The alkaline hydrolysis is favored by a pH higher then 12 as well as the urea content. A high temperature and pressure has a beneficial effect over alkaline hydrolysis.
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Wahyuniardi, Rizki, Asep Syaifulbachri, and Rasyid Algaza. "Analisis Kepuasan Pelanggan Terhadap Bauran Pemasaran Menggunakan Integrasi Importance Performance Analysis dan Model Kano (Studi Kasus : L’societe Dine and Bar Bandung)." Jurnal Rekayasa Sistem Industri 7, no. 2 (October 31, 2018): 73. http://dx.doi.org/10.26593/jrsi.v7i2.2881.73-84.
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<p>The city of Bandung has a variety of culinary places that feature their own characteristics, ranging from luxury culinary venues, traditional uniqueness hangout, to the roadside hangout is available in this city. Amid the rapid development of culinary tourism in the city of Bandung, L'societe Dine and Bar is one restaurant that wrestle in culinary tourism business competition. However, according to sales data, L'societe experienced a decrease in total sales from 2014 to 2016. L'societe requires effective improvement on its marketing mix performance. The study aims to analyze customer satisfaction with L'societe marketing mix. The research was conducted using descriptive statistics method, measuring customer satisfaction index and integration of Importance Performance Analysis and Kano Model.</p><p>Based on the result of research, there are some attributes of L'societe marketing mix that need to be improved. For price attributes, L'societe should review product prices. This review is conducted through further research on product pricing by analyzing product prices with competitor product price comparison or optimizing production costs. For promotional attributes, L'societe can hold live music on an ongoing basis. In addition to this, it can be proposed packages with attractive discounts to the customer, group or family. This is important to consider because L'societe puts forward a convenient facility to its customers to feel different from its competitors.</p><p> </p><pre><strong>Keywords</strong>: marketing mix, importance performance analysis, integration of importance performance analysis and canoe model, customer satisfaction, Kano model</pre>
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Marcotte, F., and C. P. Caulfield. "Optimal mixing in two-dimensional stratified plane Poiseuille flow at finite Péclet and Richardson numbers." Journal of Fluid Mechanics 853 (August 23, 2018): 359–85. http://dx.doi.org/10.1017/jfm.2018.565.
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We consider the nonlinear optimisation of irreversible mixing induced by an initial finite amplitude perturbation of a statically stable density-stratified fluid with kinematic viscosity $\unicode[STIX]{x1D708}$ and density diffusivity $\unicode[STIX]{x1D705}$. The initial diffusive error function density distribution varies continuously so that $\unicode[STIX]{x1D70C}\in [\bar{\unicode[STIX]{x1D70C}}-\unicode[STIX]{x1D70C}_{0}/2,\bar{\unicode[STIX]{x1D70C}}+\unicode[STIX]{x1D70C}_{0}/2]$. A constant pressure gradient is imposed in a plane two-dimensional channel of depth $2h$. We consider flows with a finite Péclet number $Pe=U_{m}h/\unicode[STIX]{x1D705}=500$ and Prandtl number $Pr=\unicode[STIX]{x1D708}/\unicode[STIX]{x1D705}=1$, and a range of bulk Richardson numbers $Ri_{b}=g\unicode[STIX]{x1D70C}_{0}h/(\bar{\unicode[STIX]{x1D70C}}U^{2})\in [0,1]$ where $U_{m}$ is the maximum flow speed of the laminar parallel flow, and $g$ is the gravitational acceleration. We use the constrained variational direct-adjoint-looping (DAL) method to solve two optimisation problems, extending the optimal mixing results of Foures et al. (J. Fluid Mech., vol. 748, 2014, pp. 241–277) to stratified flows, where the irreversible mixing of the active scalar density leads to a conversion of kinetic energy into potential energy. We identify initial perturbations of fixed finite kinetic energy which maximise the time-averaged perturbation kinetic energy developed over a finite time interval, and initial perturbations that minimise the value (at a target time, chosen to be $T=10$) of a ‘mix-norm’ as first introduced by Mathew et al. (Physica D, vol. 211, 2005, pp. 23–46), further discussed by Thiffeault (Nonlinearity, vol. 25, 2012, pp. 1–44) and shown by Foures et al. (2014) to be a computationally efficient and robust proxy for identifying perturbations that minimise the long-time variance of a scalar distribution. We demonstrate, for all bulk Richardson numbers considered, that the time-averaged kinetic-energy maximising perturbations are significantly suboptimal at mixing compared to the mix-norm minimising perturbations, and also that minimising the mix-norm remains (for density-stratified flows) a good proxy for identifying perturbations which minimise the variance at long times. Although increasing stratification reduces the mixing in general, mix-norm minimising optimal perturbations can still trigger substantial mixing for $Ri_{b}\lesssim 0.3$. By considering the time evolution of the kinetic energy and potential energy reservoirs, we find that such perturbations lead to a flow which, through Taylor dispersion, very effectively converts perturbation kinetic energy into ‘available potential energy’, which in turn leads rapidly and irreversibly to thorough and efficient mixing, with little energy returned to the kinetic-energy reservoirs.
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Carolina, Etty, Imam Santoso, and Panji Deoranto. "Pengaruh Marketing Mix (7P) dan Perilaku Konsumen Terhadap Keputusan Pembelian Produk Healthy Food Bar di Malang." Wacana, Jurnal Sosial dan Humaniora 18, no. 01 (March 11, 2015): 51–60. http://dx.doi.org/10.21776/ub.wacana.2015.018.01.6.
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Massekh, Nawal B., and Ameer A. Hillal. "Alkali-Silica. Reaction Of Foamed. Concrete Containing. Waste Glass as Aggregate." IOP Conference Series: Earth and Environmental Science 961, no. 1 (January 1, 2022): 012009. http://dx.doi.org/10.1088/1755-1315/961/1/012009.
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Abstract This research focused on examining Alkali-Silica. Reaction (ASR) of foamed concrete mixes containing1different1types of1crushed waste glass (CWG) with different chemical compositions. The reactivity was determined in sodium hydroxide solution by adopting mortar bar test. Four types of waste glass with different particle sizes and different percentages content were used. From the test results of recorded expansion of these mixes, it was noticed that the coarse glass resulted in more expansion than that of fine glass. Lead-silicate1glass (CR) exhibits the maximum expansion followed by1soda-lime1glass (SL) and boro-silicate glass (BS), while less expansion was recorded in mixes with green glass (GG). As compared to reference mix (FC), it was noted that the mixes with crushed waste glass (SL), (BS), and (CR) undergo notable expansion, while the expansion of the mixes with (GG) slightly increased compared to the reference mix (FC).
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Aperador, William, Jairo Cortes, and J. Carrillo. "Corrosion of Reinforcing Bars Astm A706 in Self-Compacting Concrete Subjected to Chloride Attack and Carbonation." Advanced Materials Research 1016 (August 2014): 315–19. http://dx.doi.org/10.4028/www.scientific.net/amr.1016.315.
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Self-compacting concrete is characterized as a system that has a mix design that increased strength and reduced amount of empty space within material. Reinforced concrete structures exposed to carbonation and chloride ion, are exposed to environmental conditions that cause degradation. Concrete were exposed to an accelerated carbonation test (3% CO2, 65% relative humidity, and 25 o C temperatures) and next it was tested under complete immersion, in 3.5 wt. % NaCl solution. . Monitoring of open-circuit potential, polarization resistance measurement and electrochemical impedance spectroscopy were used to evaluate the corrosion behavior of steel bar.
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Szablowski, Lukasz, Piotr Krawczyk, and Marcin Wolowicz. "Exergy Analysis of Adiabatic Liquid Air Energy Storage (A-LAES) System Based on Linde–Hampson Cycle." Energies 14, no. 4 (February 11, 2021): 945. http://dx.doi.org/10.3390/en14040945.
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Efficiently storing energy on a large scale poses a major challenge and one that is growing in importance with the increasing share of renewables in the energy mix. The only options at present are either pumped hydro or compressed air storage. One novel alternative is to store energy using liquid air, but this technology is not yet fully mature and requires substantial research and development, including in-depth energy and exergy analysis. This paper presents an exergy analysis of the Adiabatic Liquid Air Energy Storage (A-LAES) system based on the Linde–Hampson cycle. The exergy analysis was carried out for four cases with different parameters, in particular the discharge pressure of the air at the inlet of the turbine (20, 40, 100, 150 bar). The results of the analysis show that the greatest exergy destruction can be observed in the air evaporator and in the Joule–Thompson valve. In the case of air evaporator, the destruction of exergy is greatest for the lowest discharge pressure, i.e., 20 bar, and reaches over 118 MWh/cycle. It decreases with increasing discharge pressure, down to approximately 24 MWh/cycle for 150 bar, which is caused by a decrease in the heat of vaporization of air. In the case of Joule–Thompson valve, the changes are reversed. The highest destruction of exergy is observed for the highest considered discharge pressure (150 bar) and amounts to over 183 MWh/cycle. It decreases as pressure is lowered to 57.5 MWh/cycle for 20 bar. The other components of the system do not show exergy destruction greater than approximately 50 MWh/cycle for all considered pressures. Specific liquefaction work of the system ranged from 0.189 kWh/kgLA to 0.295 kWh/kgLA and the efficiency from 44.61% to 55.18%.
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Drastiawati, Novi Sukma, Ria Handiwi, Jarot Danang Priambodo, and Warju Warju. "Proses Normalisasi Axial Load Kiln dan Maintenance Drag Bucket (Pan Conveyor) Untuk Menjamin Kesiapan Operasional Peralatan Produksi Semen." Indonesian Journal of Engineering and Technology (INAJET) 3, no. 1 (September 27, 2020): 1–9. http://dx.doi.org/10.26740/inajet.v3n1.p1-9.
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Masterplan Percepatan dan Perluasan Pembangunan Ekonomi Indonesia berupa pembangunan infrastruktur jalan tol sepanjang 1334 km membutuhkan semen sebesar 4 juta ton. Melihat total kebutuhan semen menjadikan pabrik semen memiliki peran besar dalam mensukseskan mega proyek yang sedang dilakukan. Kegiatan produksi merupakan salah satu hal yang diperhitungkan sehingga kesiapan peralatan untuk operasional harus dilakukan sesuai dengan tahap perencanaan. Agar tahapan tersebut dapat berjalan dengan baik diperlukan proses pemeliharaan dan perawatan secara berkala. Pemeliharaan pada peralatan produksi semen mesin kiln merupakan salah satu bagian yang utama karena di dalam kiln terjadi semua proses kimia pembentukan klinker dari bahan baku untuk pembuatan (raw mix). Perawatan dilkukan pada komponen drag bucket (pan conveyor) yang berfungsi untuk membawa klinker dari cooler menuju dum clinker. Tahapan yang dilakukan untuk mendapatkan data adalah dengan melakukan observasi di lapangan. Observasi dilakukan dengan terjun langsung melalui proses pengamatan pada peralatan yang dianalisa. Tahap kedua adalah mengumpulkan data yang berupa melakukan pencatatan terhadap proses normalisasi dan maintenance. Tahap ketiga adalah analisis data yang menggunakan metode deskriptif kualitatif. Hasil yang didapatkan dengan proses adjusment sebesar 0.3 sehingga mempengaruhi axial load dari 8 bar mengalami kenaikan 24 bar, sedangkan pada tyre 2 dari 53 bar mengalami penurunan menjadi 36 bar. Proses maintenace pada drag bucket (pan conveyor) menjadikan kerja drag bucket dapat berjalan baik dengan identifikasi dari beberapa parameter diantaranya;pengangkutan material berjalan dengan sempurna karena tidak ada gangguan dari roda drag bucket , masa pakai atau life time komponen roda drag bucket lebih terjaga dan tidak menimbulkan kerusakan pada komponen lain.
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Angeloni, Giulia, Piernicola Masella, Lorenzo Guerrini, Agnese Spadi, Maria Bellumori, Marzia Innocenti, and Alessandro Parenti. "Physical and Chemical Effects of Different Working Gases in Coffee Brewing: A Case Study of Caffè Firenze." Foods 9, no. 12 (December 9, 2020): 1825. http://dx.doi.org/10.3390/foods9121825.
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(1) Background: Recently, a new espresso extraction method, Caffè Firenze, has been developed, which uses gas at operating pressures of 20 bar to obtain abundant, persistent foam. The experiment aimed to evaluate the effect of using six gases (air, argon, nitrogen, carbon dioxide, carbon/nitrogen mix, and nitrous oxide) on the foam and liquid coffee. (2) Methods: Foam volume, persistence, sugar retention time, color, and rheological properties were measured. Volatile organic compounds were also evaluated. Analyses were also carried out on the liquid coffee to determine caffeine and chlorogenic acid concentrations. (3) Results: The analysis of variance revealed significant differences between the gases for all parameters. Multivariate analysis identified three groups of gases: the first comprised air, N2, and Ar; the second CO2 and N2O; and the third comprised samples extracted with CO2/N2 mix. (4) Conclusions: The choice of gas significantly influences the drink’s chemical-physical characteristics and is fundamental for product diversification.
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Kunder, Andrea M. "RR Lyrae Variables as Tracers of the Galactic Bulge Kinematic Structure." Universe 8, no. 4 (March 25, 2022): 206. http://dx.doi.org/10.3390/universe8040206.
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RR Lyrae stars are recognized as some of the oldest stars in the Universe. In addition, they are some of the few old celestial objects for which distances can be reliably inferred. As such, these stars are excellent tracers of the oldest structures that exist in the inner Galaxy. Although the inner Galaxy is where the oldest structures in the Milky Way are thought to be hidden, it is also a region notoriously difficult to study due to high extinction and crowding. Here, I will summarize how RR Lyrae stars have been used to obtain a more complete picture of the inner Galaxy. In particular, recently, a large sample of RR Lyrae star motions through space have been obtained and compared to younger, more metal-rich stars in the bulge/bar. It is seen that the inner Galaxy RR Lyrae star kinematics are complicated by a mix of a variety of Galactic components. After isolating only those RR Lyrae stars that are confined to the bulge, a subsample of these stars have slower rotation and are less barred than the dominant bar/bulge. Curiously, there is no discernible metallicity [Fe/H] difference between these two subsamples. Old, metal-poor stars in the inner Galaxy need to be properly accounted for when discussing processes that gave rise to the formation of the inner Galaxy and the Galactic bar/bulge.
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Sujjavanich, Suvimol, Thanawat Meesak, and Duangrudee Chaysuwan. "Effect of Clay Brick Powder on ASR Expansion Control of Rhyolite Mortar Bar." Advanced Materials Research 931-932 (May 2014): 441–45. http://dx.doi.org/10.4028/www.scientific.net/amr.931-932.441.
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This paper investigated the effect of clay brick powder (BP) on expansion behaviors of mortar bars using rhyolite aggregates, local volcanic rock from central Thailand. The accelerated test condition (ASTM C 1260) was used in this study. The expansion of samples with varying percentages of BP as cement replacement were compared to those of cement mortar bars. The brick powder significantly reduced expansion of mortar bars. As the percent replacement increased, the larger percentage of expansion reduction was. Due to the possible negative effects on mechanical properties of the mixture, the amount of the supplementary materials should be kept as low as possible. The mixture with 30% BP which yielded expansion below 0.05% at 14 days after acceleration, was chosen to study the effect on strength reduction, compared to the plain mixtures under normal and accelerated conditions. Compressive strength of BP samples under accelerated condition was slightly lower (approx.4%) than that of under normal curing while the strength of control mix was significant lower (of 18%) under similar conditions.
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Vacin, Ota, Jiri Stastna, and Ludo Zanzotto. "Creep Compliance of Polymer-Modified Asphalt, Asphalt Mastic, and Hot-Mix Asphalt." Transportation Research Record: Journal of the Transportation Research Board 1829, no. 1 (January 2003): 33–38. http://dx.doi.org/10.3141/1829-05.
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The possibility of using commercial rheometers for comprehensive testing of asphalt binders, asphalt mastics, and hot-mix asphalts (HMA) is explored. Samples of one polymer-modified asphalt, its mix with fine mineral filler (mastic), and one HMA prepared with the same modified asphalt as binders were tested in the dynamic shear rheometer (DSR) and the bending beam rheometer (BBR). All tested materials can be characterized by their discrete relaxation and retardation spectra (under the condition of small deformations). DSR testing was performed in the plate–plate and the torsion bar geometry. From the obtained relaxation and retardation spectra, the shear compliance, J(t), was calculated and compared with the tensile creep compliance, D(t), measured in BBR (both creep and recovery experiments were run). A simple relationship between J(t) and D(t) was found for the asphalt binder and the asphalt mastic. In the case of HMA, the bulk compliance, B(t), contributes to D(t) at short and long times. Both the Boltzmann superposition principle and the time–temperature superposition principle hold very well for all tested materials at low temperatures. There are qualitative differences, in the rheological behavior, of the asphalt binder and asphalt mastic on one side and the HMA on the other. These differences can be seen in dynamic (DSR) as well as in transient (BBR) experiments.
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Kenny, Amit, and Amnon Katz. "Influence of the Interfacial Transition Zone Properties on Chloride Corrosion in Reinforced Concrete-Characterization of ITZ." Advanced Materials Research 95 (January 2010): 69–72. http://dx.doi.org/10.4028/www.scientific.net/amr.95.69.
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Large part of life cycle cost of reinforced concrete structures, especially infrastructures, is maintenance costs, where steel corrosion induced by chlorides is the major part [1, 2]. Normally, concrete provides the reinforcing steel an environment that preserves it in its passive state. High chloride concentration in the vicinity of the steel can lead, however, to steel activation [3]. The chloride threshold for steel activation was found to be significantly different in variety of the closely related environments of concretes, mortars, and simulated pore solution. In concretes and mortars the chloride threshold was found to be significantly higher than that in simulated pore solutions [4]. Two parameters can be the underlying mechanism for this observation: 1. Concrete chemistry is different than that of the paste and common simulated pore solutions, or 2. the micro-structure of the concrete-steel interface is different [5, 6]. Soluble silicate ions in the pore solution, which may arise from the cement, pozzolans or aggregates, also influence the chloride threshold. Several studies showed that the passivation film formed in the presence of dissolved silicate is significantly different from that created in its absence. Hence, chemical differences in concrete composition, especially in the presence of pozzolans, can influence the chloride threshold [7-10]. Localized corrosion is explained by a mechanism of local concentration polarization across a pit or crevice. This mechanism is closely related to the local geometry. Thus, the micro-structure of concrete-steel interface may influence the levels at which concentration polarization occurs, thus affecting the chloride threshold and the localized corrosion development. Results from various studies on concrete reinforcement corrosion, support the model that explains localized corrosion by concentration polarization [11]. In this work, the concrete-steel interfacial transition zone (ITZ) is quantitatively characterized from back scattered electron microscopy images and pullout test, and is used for correlation with chloride threshold. A series of different concretes with different ITZ structure in the concrete-steel interface have been prepared. for each mix, specimens prepared for corrosion experiment, ITZ characterization, and pullout test. Corrosion experiment for chloride threshold is performed by unidirectional diffusion and capillary suction of 6% NaCl solution. Steel activation is monitored by half cell potential measurement; potential measurement of the tested bar against a second bar, located farther from the NaCl solution, as an internal reference; and electrochemical impedance spectroscopy (EIS). When steel activation is observed, the concrete is drilled at the bar depth for chloride analysis. The method for quantification of the ITZ by image analysis is composed of three stages: image acquisition by SEM (Scanning Electron Microscope) on BEI (Backscattered Electron Image) mode, image classification into phases, and ITZ character quantification. Image classification is done by transforming the image, which contain only a scalar for any pixel, into multi-dimensional image, which contain a vector of properties scalar for any pixel. Transformation into multi-dimensional image is accomplished by filtering through various filters, to calculate pixel neighborhood parameters as average and texture. Than the Mean-Shift algorithm [12] is used for unsupervised image clustering, followed by classifying the clusters into physical phases. ITZ characters quantified are: ITZ thickness, and average and maximum of the minimal distance between steel and concrete for every pixel on the steel perimeter. In this work, ITZ thickness is defined by two separate algorithms: 1. the distance from the steel where porosity sharply decline, and 2. the distance from the steel where the porosity decreases to the average porosity 300 micrometers away from the steel surface. Minimal distance between steel and concrete is defined for any pixel on the steel surface as the closest solid concrete pixel. Pullout test is used for physical-performance characterization of the ITZ. Those physical characteristics are: slop at the linear region, bonding strength, maximum stress, and de-bonding energy. Not enough data obtained so far, for chloride ITZ relationship determination. Thus, this paper deals with the ITZ characterization and its relationship with the concrete mix properties. Because, no standard method exists for ITZ measurements and characterization, correlation between characters of the ITZ as obtained by the different methods listed above is needed in order to establish confidence. Low co-linearity between methods can result from: high variation of the ITZ among specimens from the same mix, nonlinear relationship, method inaccuracy, method measure different and unrelated characters, or the measured parameter is not a representative characteristic of the ITZ. Parameters of the minimum distances between steel and concrete were found to correlate with each other. Those parameters were found to be better correlated for vertical bars, while for the horizontal bars, ITZ thicknesses are better correlated. A combination of the different nature of the ITZ around vertical and horizontal bar with miss-classification of some pixels seems to be the cause for that. Typical measurements of ITZ thickness are 40 micrometer for vertical bars and 400 micrometer for horizontal ones. Typical maximum distances between steel and concrete are 12 micrometer for vertical bars and 25 micrometer for horizontal ones. Pullout test results per-se do not correlate due to scattered results. The averages of the results per mix are correlated. These results are better correlated when horizontal and vertical bars are dealt separately. Vertical bars properties are less correlated than the horizontals. The maximum stress during pullout of vertical bars is negatively correlated with the ITZ thickness, and the bonding strength is negatively correlated with the maximum porosity of the ITZ. The maximum stress of horizontal bars is negatively correlated with the ITZ thickness, as well as the bonding strength, and the measurement of the thickness by porosity drop yielded the best correlation. De-bonding energy, on the other hand, is positively correlated with parameters of minimum distance between steel and concrete, and with the ITZ thickness as measured by the average porosity method. Plotting relationships like ITZ thickness (porosity drop method) vs. maximum stress for all specimens demonstrate a relationship which is not linear (Figure 1). Mix properties influence on ITZ is highly bar orientation depended. For vertical bars, linear correlation with the mix properties is weak. A positive correlation can be found between the slump to the maximum of average distance between concrete and steel, and maximum porosity. This contrasts a reasonable assumption that higher slump will cause better consolidation around the rebar and will result in a denser ITZ. The variability of ITZ around a single bar, as represented by the maximum of the standard deviations of the distances between concrete and steel, increases as the bleeding duration increases. Other ITZ properties have some correlation with the bleeding duration as well. It may indicate some un-measured rheological properties of the fresh concrete, which influence the ITZ formation. Increase of powder content seems to reduce the maximum porosity around vertical bars. The energy absorbed during pullout is the only parameter that is well correlated with the mix properties for vertical bars. The w/c ratio, total bleeding, and bleeding rate contribute to increase the bonding energy of the vertical bars, while tend to decrease the bonding strength for horizontal bars as those properties increase. This result could be an indication for ITZ structure formation mechanism around vertical bars, which creates a microstructure that influences the fracture mechanism. For horizontal bars, the mix properties that best correlate with ITZ parameters are: powder content and water content, for the maximum ITZ thickness; and total bleeding, bleeding rate, and water content, for the average ITZ thickness. It can be inferred that raising both powder content and water content make the ITZ smaller. Powder content found to increase the average of the maximum porosity, but not to increase the maximum value itself. That means more evenly distributed porosity around the rebar when powder content is high. Water content is, commonly, associated with higher bleeding, which was found to make the ITZ thicker, but no correlation between water content and bleeding was found in the current work. Bleeding rate and total bleeding are highly correlated with the ITZ. Both found to increase the ITZ thickness. Water to cement ratio is somewhat correlated with the average of the ITZ thickness. That can be a result of negative correlation of the water to cement ratio with the powders content. Pullout parameters of horizontal bars are well correlated with mix properties. The only pullout parameter, which dose not correlate well with mix properties, is the de-bonding energy. The mix properties which are correlated with the pullout parameters are: total bleeding, bleeding rate, w/c ratio, and powders content. The water content found to have no correlation with all pullout parameters. The bleeding properties, total bleeding and bleeding rate, are unsurprisingly correlated as could be predicted by bleeding water lens formation phenomenon [5, 13], and as found by using image analysis. Water to cement ratio, is well correlated with the pullout parameters, as could be predicted, because it influences both concrete strength and bleeding. Powder content has lower linear correlation with the pullout parameters, compared with w/c ratio. Considering observations of other researchers, which emphasized the importance of voids at the steel bar-concrete interface [5, 6], a pronounced difference of chloride threshold is expected for vertical bars, relatively to horizontal, and among horizontal bars. The factor influencing the ITZ thickness around, or more accurately below, horizontal bars is the water bleeding. In practical use, the considered bleeding is the total bleeding below the bar, not the mix bleeding per-se, as was demonstrated by results of pullout tests [14]. It can be concluded that reducing water to powder ratio will reduce bleeding and consequently the ITZ thickness below horizontal bars, which is expected to increase chloride threshold and corrosion resistance.
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Maha, Ummi Khairiyah Br, Hermansyah Hermansyah, and Dedy Dharmawansyah. "Perencanaan Perkerasan Kaku Jalan Eksisting Lenangguar – Lunyuk STA 04 – STA 06." INERSIA: lNformasi dan Ekspose hasil Riset teknik SIpil dan Arsitektur 17, no. 1 (May 28, 2021): 76–82. http://dx.doi.org/10.21831/inersia.v17i1.39500.
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ABSTRACT The existence of roads is essential to support economic growth, agriculture, and other sectors. This is because the road is an essential means of transportation to serve people and goods from one place to another safely, comfortable, and economical. Therefore, it is necessary to plan related to the road pavement. Inappropriate pavement planning is the main cause of road damage. The planning for rigid pavement refers to the often-used guidelines, namely, the Road Pavement Design Manual (Revised on June 2017). The thick design of rigid pavement for the Lenangguar - Lunyuk, using quality of concrete of K400 with a thickness of 19 cm. The sub-foundation uses Lean Mix Concrete with K125 concrete quality and 10 cm of thickness. Dowel 33 mm in diameter uses steel bars 45 cm in length and 40 cm distances. Tie Bar fastener with 16 mm in diameter using a threaded rod, length 70 cm, and distance between rods 75 cm, respectively. ABSTRAKKeberadaan jalan raya sangatlah penting untuk menunjang laju pertumbuhan ekonomi, pertanian dan sektor lainnya. Hal ini dikarenakan jalan merupakan suatu sarana transportasi yang sangat penting untuk melayani pergerakan manusia dan atau barang dari suatu tempat ke tempat lain secara aman, nyaman dan ekonomis, maka dari itu perlu dilakukan perencanaan terkait perkerasan jalan. Perencanaan perkerasan jalan yang tidak sesuai menjadi penyebab utama dari kerusakan jalan. Perencanaan pekerasan kaku ini mengacu pada pedoman yang sering digunakan yaitu, Manual Desain Perkerasan Jalan (Revisi Juni 2017). Dalam rancangan tebal perkerasan kaku jalan lintas Lenangguar – Lunyuk, menggunakan beton K 400 dengan tebal 19 cm. Pondasi bawah menggunakan Lean Mix Concrete dengan mutu beton K 125 dengan tebal 10 cm. Dowel berdiameter 33 mm menggunakan ruji baja polos degan panjang 45 cm dan jarak 40 cm. Pengikat Tie Bar berdiameter 16 mm menggunakan batang ulir, panjang 70 cm dan jarak antar batang 75 cm.
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Iqbal, S., N. Ullah, and A. Ali. "Effect of Maximum Aggregate Size on the Bond Strength of Reinforcements in Concrete." Engineering, Technology & Applied Science Research 8, no. 3 (June 19, 2018): 2892–96. http://dx.doi.org/10.48084/etasr.1989.
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The bond between reinforcements and concrete is the only mechanism that transfers the tensile stresses from concrete to reinforcements. Several factors including chemical adhesion, roughness and reinforcement interface and bar bearing affect the bond strength of reinforcements with concrete. This work was carried out considering another varying factor which is maximum aggregate size. Four mixes of concrete with similar compressive strengths but different maximum aggregate sizes of 25.4mm, 19.05mm, 12.7mm and 9.53mm were used with the same bar size of 16mm. Compressive strength, splitting tensile strength and bond strength for each concrete mix were studied. Test results depict a slight increase in compressive and splitting tensile strength with decrease in maximum aggregate size. The bond strength remained at the same level with decrease in maximum aggregate size except at maximum aggregate size of 9.53mm when there was a drop in bond strength, despite better compressive and splitting tensile strengths. ACI-318 and FIB-2010 codes equation for bond strength calculation work well only when the maximum aggregate size is 12.7mm and above. Therefore, maximum aggregate size is critical for bond strength when smaller size aggregates are used.
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Park, Ki-Tae, Hee-Ju Kim, Young-Jun You, Sang-Yoon Lee, and Dong-Woo Seo. "An Experimental Study for Calculating Proper Mix Proportion according to Curing Time of Synthetic Resins in FRP Hybrid Bar." Journal of the Korean Society for Advanced Composite Structures 7, no. 3 (September 30, 2016): 35–40. http://dx.doi.org/10.11004/kosacs.2016.7.3.035.
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Xie, Heng Yan, and Xin Zheng. "Preparation and Basic Mechanical Properties of Self-Compacting Concrete." Advanced Materials Research 150-151 (October 2010): 354–57. http://dx.doi.org/10.4028/www.scientific.net/amr.150-151.354.
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Self- compacting concrete (SCC) has characteristics of good flow-ability, non-vibrating and self-compacting. It is the optimum to be used in concrete members with densely distributed steel bar and concrete is inconvenient to be vibrated. The mixture ratio of design grade of C20 and C40 SCC commonly used in project is given after trial mix. The compression stress-strain relation of SCC prism is obtained by MTS. The Mechanical property indexes of SCC are got. The ultimate compression strain of the extreme fiber is acquired by testing beam made of SCC, and the relation between the ultimate compression strain of the extreme fiber in flexural member and the strain at the peak of the stress-strain curve subjected to uniaxial compression is given.
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Kamau, John, and Ash Ahmed. "Performance of Ternary Corncob Ash and Anthill Soil Concrete in Sulfate Solutions." European Journal of Engineering Research and Science 2, no. 9 (September 13, 2017): 12. http://dx.doi.org/10.24018/ejers.2017.2.9.456.
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Durability of concrete has been defined as its ability to withstand deterioration after it has been exposed to the environment of its intended use. This work examined the performance of ternary Corncob Ash (CCA) and Anthill Soil (AHS) concrete in sodium sulfate (Na2SO4), magnesium sulfate (MgSO4) and combined Na2SO4 and MgSO4 solutions. Bar specimens for elongation tests and cubes for strength deterioration tests were cast using combined CCA and AHS at the 5% replacement, which was earlier on reported to have achieved the highest compressive strength, as well as at the 30% replacement. From the findings, it was concluded that at the 5% replacement, the ternary mix could be used with an advantage over 100% cement concrete in MgSO4 environments.
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Kamau, John, and Ash Ahmed. "Performance of Ternary Corncob Ash and Anthill Soil Concrete in Sulfate Solutions." European Journal of Engineering and Technology Research 2, no. 9 (September 13, 2017): 12–16. http://dx.doi.org/10.24018/ejeng.2017.2.9.456.
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Durability of concrete has been defined as its ability to withstand deterioration after it has been exposed to the environment of its intended use. This work examined the performance of ternary Corncob Ash (CCA) and Anthill Soil (AHS) concrete in sodium sulfate (Na2SO4), magnesium sulfate (MgSO4) and combined Na2SO4 and MgSO4 solutions. Bar specimens for elongation tests and cubes for strength deterioration tests were cast using combined CCA and AHS at the 5% replacement, which was earlier on reported to have achieved the highest compressive strength, as well as at the 30% replacement. From the findings, it was concluded that at the 5% replacement, the ternary mix could be used with an advantage over 100% cement concrete in MgSO4 environments.
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Han, Bin, Wei Sun, Shaofeng Yu, Chao Liu, Song Yao, and Jianxun Wu. "Performance Comparison between Neutralization Tailings and Flotation Tailings Used for Backfill Mix and Mechanism Analysis." Advances in Materials Science and Engineering 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/1087269.
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A comparison test of different tailings used for underground backfill was conducted, using neutralized tailings from BIOX and flotation tailings of Jinfeng Mine. Laboratory comparison test results show that, with neutralized tailings, when the cement dosage is at 19%, backfill UCS after 7 days, 14 days, and 28 days are 105%–163%, 80%–102%, and 33%–43%, respectively, which are higher than those of flotation tailings. When the cement dosage is at 12%, backfill UCS after 7 days, 14 days, and 28 days are 58%–77%, 50%–60%, and 28%–51%, respectively, which are higher than those of flotation tailings. Slurry fluidity of neutralized tailings is lower than that of flotation tailings, while, in these two tailings, the difference of slump and diffusivity values is less than 6%, which is not a significant difference in slurry fluidity. The reason for neutralized tailings showing higher UCS is as follows: during backfill curing, neutralization tailings produce abundant crystals of CaSO4·2H2O in interlaced structure which helps in combining aggregates closely; CaSO4·2H2O hydrates with C3A C4AF contained in the cement and forms clavate cement bacillus which works as a micro reinforcing steel bar. The test proved that neutralized tailings are more optimal for backfilling.
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Basarab, J. A., J. L. Aalhus, M. A. Shah, P. S. Mir, V. S. Baron, M. Dugan, E. K. Okine, and W. M. Robertson. "Effect of feeding sunflower seeds on the performance, carcass characteristics, meat quality, retail stability and sensory characteristics of pasture-fed and feedlot finished beef." Canadian Journal of Animal Science 87, no. 1 (March 1, 2007): 15–27. http://dx.doi.org/10.4141/a06-047.
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This study examined the effects of whole sunflower seed (WSS) supplementation on production parameters, carcass traits, and organoleptic characteristics of beef from steers slaughtered directly off pasture or after receiving a finishing diet. Ninety-six yearling steers (410 kg; SD = 44 kg) were randomly allocated to three pasture (P) dietary treatments: (1) supplemented with P-WSS (n = 48), (2) supplemented with cracked barley grain (P-BAR, n = 24), and (3) not supplemented (P-CON, n = 24). Steers rotationally grazed meadow bromegrass-alfalfa pasture for 66 d during the summer and consumed WSS and BAR at a rate of 0.75 and 1.79 kg head-1 d-1, respectively. At the end of summer grazing half the steers from each pasture dietary treatment group were moved to a feedlot (F) where they were fed high barley-based finishing diets. The remaining 48 steers continued with their dietary treatments on stockpiled pasture for an additional 47 d (SD = 11) until they were slaughtered directly off pasture. In the feedlot, half the steers from each pasture dietary treatment were fed either a control [83% rolled barley, 10% alfalfa hay, 5% barley silage, 1% molasses and 1% vitamin/mineral mix on a dry matter (DM) basis; F-CON] or a F-WSS diet (68% rolled barley, 15% WSS, 10% alfalfa hay, 5% barley silage, 1% molasses and 1% vitamin/mineral mix on a DM basis) for a further 94 d until slaughter. Supplementation of BAR on pasture increased average daily gain (ADG), while supplementation of WSS had no effect on ADG compared with no supplementation (0.73 vs. 0.58 vs. 0.55 kg d-1, P = 0.023). Inclusion of 15% WSS in the finishing diet decreased ADG (1.46 vs. 1.72 kg d-1, P = 0.038), dry matter intake (DMI) (11.6 vs. 12.6 kg d-1, P = 0.058) and had no effect on feed to gain ratio (8.0 vs. 7.4 kg d-1, P = 0.160). Provision of WSS on pasture or in finishing diets had no effect on carcass traits and organoleptic characteristics of beef from steers slaughtered directly off pasture or after receiving a finishing diet. Slaughtering steers directly off pasture, regardless of pasture dietary treatment, adversely affected most carcass merit, meat quality and retail appearance and acceptability parameters compared with steers finished on a high-barley grain diet. These results indicate that increasing the dietary polyunsaturated fatty acids threefold in the pasture dietary treatment or greater than eightfold in the finishing diets had a small negative effect on animal growth rate and no adverse effect on carcass merit, meat quality and retail acceptability. Key words: Polyunsaturated fatty acids, retail acceptability, beef cattle
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Haddad, Rami H., and Ahmed M. Ashteyate. "Role of synthetic fibers in delaying steel corrosion cracks and improving bond with concrete." Canadian Journal of Civil Engineering 28, no. 5 (October 1, 2001): 787–93. http://dx.doi.org/10.1139/l01-037.
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An experimental study was conducted to investigate the bond behavior between corroding reinforcing steel and surrounding synthetic fiber reinforced concrete. Pullout concrete and fiber reinforced concrete specimens were prepared at concrete cover to steel bar diameter ratios of 3.1 and 3.7 with three embedded lengths of 100, 200, and 300 mm. Fiber reinforced concrete was prepared using polypropylene at 0.15% and 0.30% or nylon fibers at 0.3% by mix volume. After moist curing for 90 days, pullout specimens, originally contaminated by up to 11 kg/m3 NaCl, were subjected to a special treatment to accelerate corrosion in steel. The bond stressslippage relationship was evaluated at different corrosion levels. The findings indicated that the use of fibers delayed initiation of cracking, due to steel corrosion, and improved the ultimate bond strength at cracking and post-cracking stages. The percentage improvement in ultimate bond strength at the latter stages reached as high as 52% and 87%, respectively. It was noticed that, prior to cracking, corrosion of steel bars resulted in an increase in bond strength, regardless of the concrete cover to bar diameter ratio used, or whether fibers were used or not. After cracking (due to steel corrosion), pullout specimens prepared with polypropylene fibers showed better resistance than that of corresponding ones with nylon fibers.Key words: fibers, reinforced concrete, corrosion, cracking, bond strength, slippage.
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Zurita, A., E. Florido, F. Bresolin, E. Pérez-Montero, and I. Pérez. "Bar effect on gas-phase abundance gradients. I. Data sample and chemical abundances." Monthly Notices of the Royal Astronomical Society 500, no. 2 (August 18, 2020): 2359–79. http://dx.doi.org/10.1093/mnras/staa2246.
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ABSTRACT Studies of gas-phase radial metallicity profiles in spirals published in the last decade have diminished the importance of galactic bars as agents that mix and flatten the profiles, contradicting results obtained in the 1990s. We have collected a large sample of 2831 published H ii region emission-line fluxes in 51 nearby galaxies, including objects both with and without the presence of a bar, with the aim of revisiting the issue of whether bars affect the radial metal distribution in spirals. In this first paper of a series of two, we present the galaxy and the H ii region samples. The methodology is homogeneous for the whole data sample and includes the derivation of H ii region chemical abundances, structural parameters of bars and discs, galactocentric distances, and radial abundance profiles. We have obtained O/H and N/O abundance ratios from the Te-based (direct) method for a subsample of 610 regions, and from a variety of strong-line methods for the whole H ii region sample. The strong-line methods have been evaluated in relation to the Te-based one from both a comparison of the derived O/H and N/O abundances for individual H ii regions and a comparison of the abundance gradients derived from both methodologies. The median value and the standard deviation of the gradient distributions depend on the abundance method, and those based on the O3N2 indicator tend to flatten the steepest profiles, reducing the range of observed gradients. A detailed analysis and discussion of the derived O/H and N/O radial abundance gradients and y-intercepts for barred and unbarred galaxies is presented in the companion Paper II. The whole H ii region catalogue including emission-line fluxes, positions, and derived abundances is made publicly available on the CDS VizieR facility, together with the radial abundance gradients for all galaxies.
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Collins, John. "A Brief History of Cannabis and the Drug Conventions." AJIL Unbound 114 (2020): 279–84. http://dx.doi.org/10.1017/aju.2020.55.
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“Drugs” have been regulated at the international level since 1912, while cannabis has been specifically regulated since 1925. Contemporary local, national, and international cannabis regulations are now diverging, with some jurisdictions legalising its recreational production, sale and consumption. This essay explores the legal and historical complexity and contingencies around the development of international cannabis regulations and prohibitions. It highlights that the global drug control system was not solely focused on prohibition and instead was a complex mix of regulations underpinned by frequently ill-defined and unclear prohibitions. It argues that the international drug control system should not serve as a bar to national-level reforms and that the two can continue to coexist. The essay favors a flexible, functional and pragmatic interpretation and implementation of the system as the most likely and indeed preferred outcome of international cannabis policy reforms.
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Kotari, Sairam, and Eshwaraiah Punna. "Mechanical And Metallurgical Investigation Of Tig Welded-Brazed Aluminum And Stainless Steel Disimilar Joint By Using Copper Filler Rod." Journal of University of Shanghai for Science and Technology 23, no. 09 (September 7, 2021): 187–95. http://dx.doi.org/10.51201/jusst/21/09534.
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Automobile bodies made by mix of steel and aluminum composites are getting famous in present days to decrease weight. Present work means to exhibit the strength of Aluminum and steel welded joint. Primary measures centered in this work are strength forecast, streamlining of welding measure boundaries and investigation of intermetallics. Base materials utilized are AA6061 aluminum alloys and SS304 hardened steel alloy. BCuP-4 copper filler bar is utilized for TIG welding/brazing of base metals. Taguchi L27 symmetrical exhibit with three elements is taken for plan of analyses. Analysis of Variance (ANOVA) a tool used to determine a remarkable effect of welding parameters and their performance significantly. In addition, experimental Tensile strength is compared to predicted values based on ANN. The results were found to be satisfactory. Formation Of IMCs were studied by doing SEM analysis.
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Jhatial, Ashfaque Ahmed, Aamir Khan Mastoi, Zafar Ali Siyal, Touqeer Ali Rind, and Imtiaz Ahmed Memon. "Influence of Long Polypropylene Fibre on the Properties of Concrete." Quaid-e-Awam University Research Journal of Engineering, Science & Technology 18, no. 02 (December 31, 2020): 38–43. http://dx.doi.org/10.52584/qrj.1802.06.
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Concrete is the most used building and construction material globally due to the ease of availability and durability. It is a well-known fact that concrete can easily withstand compressive stresses; however, it fails under tension. To improve this deficiency, steel bar reinforcement has been used. However, with the steel reinforcement, additional permanent self-weight is transferred on the structure and is prone to corrosion. Hence, engineers and researchers have been working to search for more sustainable reinforcing material that could be cost-effective and simultaneously increase tensile strength. This experimental work was carried out to study the influence of long (38.1 mm) polypropylene (PP) fibres on the workability and mechanical strengths (compressive and flexural) of concrete. Three different fibre fraction content, 0.20%, 0.25% and 0.30% were selected to reinforce concrete. A total of 12 cylinders of 300mm×150mm dimension (3 cylinders per mix) and 12 beams of 609.6mm×304.8mm×101.6mm dimension (3 beams per mix) were used to determine the compressive strength and flexural strength after the samples achieved 28 days curing. Based on the results, it can be observed that longer fibres do not significantly influence the compressive strength as much as they do on flexural strength. Furthermore, longer length fibres, like shorter fibres, obstruct the workability of concrete. Comparing with previous findings, it can be concluded that for patching of macrocracks, longer length PP fibres should be used.
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Zhou, Sheng-quan, Da-wei Zhou, Yong-fei Zhang, Wei-jian Wang, and Dongwei Li. "Research on the Dynamic Mechanical Properties and Energy Dissipation of Expansive Soil Stabilized by Fly Ash and Lime." Advances in Materials Science and Engineering 2019 (December 6, 2019): 1–13. http://dx.doi.org/10.1155/2019/5809657.
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To probe into the dynamic mechanical properties of expansive soil stabilized by fly ash and lime under impact load, the split-Hopkinson pressure bar (SHPB) test was carried out in this study. An analysis was made on the dynamic mechanical property and final fracture morphology of stabilized soil, and the failure mechanism was also explored from the perspective of energy dissipation. According to the test results, under the impact pressure of 0.2 MPa, plain soil and pure fly ash-stabilized soil exhibit strong plasticity. After the addition of lime, the stabilized soil shows obvious brittle failure. The dynamic compressive strength and absorbed energy of stabilized soil first increase and then decrease with the change of mix proportions. Both the dynamic compressive strength and the absorbed energy reach the peak value at the content of 20% fly ash and 5% lime (20% F + 5% L). In the process of the test, most of the incident energy is reflected back to the incident bar. The absorbed energy of stabilized soil increases linearly with the rise of dynamic compressive strength, while the absorbed energy is negatively correlated with the fractal dimension. The fractal dimension of pore morphology of the plain soil is lower than that of the fly ash-lime combined stabilized soil when it comes to the two different magnification ratios. The test results indicate that the modifier content of 20% F + 5% L can significantly improve the dynamic mechanical properties of the expansive soil.
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Won, Jong-Pil, Chan-Gi Park, Hwang-Hee Kim, Sang-Woo Lee, and Cheol Won. "Bond Behaviour of Frp Reinforcing Bars in High-Strength Steel Fibre-Reinforced Concrete." Polymers and Polymer Composites 15, no. 7 (October 2007): 569–78. http://dx.doi.org/10.1177/096739110701500707.
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Current design trends for structures require the increased use of high-strength concrete, which has a compressive strength of over 80 MPa. Its enhanced strength, however, leads to brittle failure problems, which have been resolved by adding steel fibres. Fibre-reinforced polymer (FRP) is actively being studied to resolve the corrosion problems encountered with steel reinforcing bars in concrete structures exposed to adverse environmental conditions. In this study, we experimentally evaluated the bond behaviour of FRP reinforcing bars in high-strength steel fibre-reinforced concrete. A high-strength concrete mix was created with a target strength of over 80 MPa, and steel fibre was added. The FRP reinforcing bars had an increased pullout load with a slow gradient, and the slope of the pullout load reduction curve remained small after the maximum pullout load was reached. In addition, the bond strength increased as steel fibre was added to the FRP reinforcing bar.
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Ismail, Sallehan, Mohamad Asri Abd Hamid, and Zaiton Yaacob. "Effect of the Fine Recycled Aggregates on the Dynamic Compressive Behavior of Recycled Mortar." Materials Science Forum 991 (May 2020): 62–69. http://dx.doi.org/10.4028/www.scientific.net/msf.991.62.
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This study aims to investigate the dynamic behavior of recycled mortar under impact loading using a split Hopkinson pressure bar (SHPB). Several mortar mixtures were produced by adding various fine recycled aggregates (FRA) to the mixture in replacement percentages of 0%, 25%, 50%, 75%, and 100% of the natural fine aggregate (NFA). The effects of strain rate on compressive strength and specific energy absorption were obtained. Results show that the dynamic compressive strength and specific energy absorption of recycled mortar are highly strain rate dependent; specifically, they increase nearly linearly with the increase in peak strain rate. However, the compressive strength and specific energy absorption of recycled mortar are generally lower than those of NFA mortar (reference samples) under similar high strain rates. The findings of this research can help researchers and construction practitioners to ascertain the appropriate mix design procedure to optimize the impact strength properties of recycled mortar for protective structural application.
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Banda-Barragán, W. E., M. Brüggen, C. Federrath, A. Y. Wagner, E. Scannapieco, and J. Cottle. "Shock–multicloud interactions in galactic outflows – I. Cloud layers with lognormal density distributions." Monthly Notices of the Royal Astronomical Society 499, no. 2 (September 23, 2020): 2173–95. http://dx.doi.org/10.1093/mnras/staa2904.
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ABSTRACT We report three-dimensional hydrodynamical simulations of shocks (${\cal M_{\rm shock}}\ge 4$) interacting with fractal multicloud layers. The evolution of shock–multicloud systems consists of four stages: a shock-splitting phase in which reflected and refracted shocks are generated, a compression phase in which the forward shock compresses cloud material, an expansion phase triggered by internal heating and shock re-acceleration, and a mixing phase in which shear instabilities generate turbulence. We compare multicloud layers with narrow ($\sigma _{\rho }=1.9\bar{\rho }$) and wide ($\sigma _{\rho }=5.9\bar{\rho }$) lognormal density distributions characteristic of Mach ≈ 5 supersonic turbulence driven by solenoidal and compressive modes. Our simulations show that outflowing cloud material contains imprints of the density structure of their native environments. The dynamics and disruption of multicloud systems depend on the porosity and the number of cloudlets in the layers. ‘Solenoidal’ layers mix less, generate less turbulence, accelerate faster, and form a more coherent mixed-gas shell than the more porous ‘compressive’ layers. Similarly, multicloud systems with more cloudlets quench mixing via a shielding effect and enhance momentum transfer. Mass loading of diffuse mixed gas is efficient in all models, but direct dense gas entrainment is highly inefficient. Dense gas only survives in compressive clouds, but has low speeds. If normalized with respect to the shock-passage time, the evolution shows invariance for shock Mach numbers ≥10 and different cloud-generating seeds, and slightly weaker scaling for lower Mach numbers and thinner cloud layers. Multicloud systems also have better convergence properties than single-cloud systems, with a resolution of eight cells per cloud radius being sufficient to capture their overall dynamics.
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Rodseanglung, Thirada, Tanakorn Ratana, Monrudee Phongaksorn, and Sabaithip Tungkamani. "Biofuel Production from Jatropha Bio-Oil Derived Fast Pyrolysis: Effect of Catalysts Supported." Key Engineering Materials 841 (May 2020): 150–54. http://dx.doi.org/10.4028/www.scientific.net/kem.841.150.
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This research focus on catalytic hydrotreating of Jatropha Bio-oil derived fast pyrolysis into biofuel was investigated to determine the effects of the supported type (Al2O3 TiO2 and Al2O3-TiO2 mix-oxide) and of the variables temperature (300-340 °C). The synthesized catalysts were prepared by sol-gel method for support and wet-impregnation with solution promoter on support, and characterization by BET NH3-TPD XRD and NO-TPD for active site analysis of catalysts. The reaction was carried out in a Parr batch reactor under H2 atmosphere about 50 bar for 2 h. The catalytic activity was evaluated for % fatty acid conversion (%FFA), %HDO, %selective to paraffin/olefin products. The results showed that the CMA gave the %FFA is highest, but low selective products, then the CMT gave the % HDO high than CMA, while the mixed-oxide were proving the %HDO, %FFA conversion and % selective is increasing because the TiO2 incorporated with Al2O3 effect to increase the amount of rim site, it’s active site for HYD partway.
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Dobruský, Svatopluk, Daniele Forni, and Ezio Cadoni. "Response of UHPFRCs in Tension under High Stress Rate." EPJ Web of Conferences 183 (2018): 04003. http://dx.doi.org/10.1051/epjconf/201818304003.
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The paper presents a part of a full-experimental campaign characterizing various Ductal® mix designs (compressive strength of 150, 170, 210MPa) with various dosages of fibers (2% and 3.25%). The dynamic tests are performed by means of two Modified Hopkinson Bar devices with that are installed at the DynaMat Laboratory in Lugano. The tests, in tension at different velocities were performed on cylindrical notched specimens of 60mm in diameter and 60mm height (notch/radius = 0.20). The preliminary results present different rate sensitivity of the materials. Different behaviours are registered for the materials having matrix with special thermal curing respect to those cured as usual. An important increment of stress was obtained for the matrix where sand was partially replaced by Silica Fume. These results are the base for better understanding the mechanical behaviour in dynamic that will be obtained by further tests on Ultra-High Performance Fibre-Reinforced Concretes (various Ductal® classes). Such data will provide designers better overview of relevant properties of these materials for design of protective structures.
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Chien Yet, Tan, R. Hamid, and Mudiono Kasmuri. "Dynamic Stress-Strain Behaviour of Steel Fiber Reinforced High-Performance Concrete with Fly Ash." Advances in Civil Engineering 2012 (2012): 1–6. http://dx.doi.org/10.1155/2012/907431.
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The addition of steel fibers into concrete mix can significantly improve the engineering properties of concrete. The mechanical behaviors of steel fiber reinforced high-performance concrete with fly ash (SFRHPFAC) are studied in this paper through both static compression test and dynamic impact test. Cylindrical and cube specimens with three volume fractions of end-hooked steel fibers with volume fraction of 0.5%, 1.0%, and 1.5% (39.25, 78.50, and 117.75 kg/m3) and aspect ratio of 64 are used. These specimens are then tested for static compression and for dynamic impact by split Hopkinson pressure bar (SHPB) at strain rate of 30–60 s−1. The results reveal that the failure mode of concrete considerably changes from brittle to ductile with the addition of steel fibers. The plain concrete may fail under low-strain-rate single impact whereas the fibrous concrete can resist impact at high strain rate loading. It is shown that strain rate has great influence on concrete strength. Besides, toughness energy is proportional to the fiber content in both static and dynamic compressions.
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Amini Pishro, Ahad, and Xiong Feng. "Experimental and Numerical Study of Nano-Silica Additions on the Local Bond of Ultra-High Performance Concrete and Steel Reinforcing Bar." Civil Engineering Journal 3, no. 12 (January 4, 2018): 1339. http://dx.doi.org/10.28991/cej-030962.
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Micro-silica is widely used as an additive to cement in producing high performance concrete. This matter is used to enhance the strength and efficiency of concrete. Recently, due to the development of advanced nano-technology, nano-silica has been produced with particle sizes smaller than micro-silica and higher pozzolanic activity. Studies show that addition of nano-silica into cement-based materials improves their mechanical properties. Considering the unique characteristics of nano-silica, it seems that this material can be used in ultra-high performance concrete (UHPC). Therefore, further studies are needed on how the local bond and bond stress of steel reinforcing bar and UHPC containing nano-silica would be effected. In the present study, after preparing the mix designs and proposed specimens, the effects of various parameters on the local bond of steel reinforcing bars and UHPC containing nano-silica were examined by pullout experiments. In this research, we have numerically investigated the bond strength using numerical methods and calibration of the ABAQUS results in addition to its experimental study of ultra-high performance concrete and steel reinforcement. In numerical analysis, the concrete damage plasticity method was used to simulate the nonlinear behavior of concrete and its strain softness. Comparing between numerical and experimental analysis results shows that numerical analysis with high precision can predict the bond stress, bond load, and concrete specimen fracture mode.
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Ramesh, T., A. P. Sathiyagnanam, Melvin Victor De Poures, and P. Murugan. "A Comprehensive Study on the Effect of Dimethyl Carbonate Oxygenate and EGR on Emission Reduction, Combustion Analysis, and Performance Enhancement of a CRDI Diesel Engine Using a Blend of Diesel and Prosopis juliflora Biodiesel." International Journal of Chemical Engineering 2022 (May 14, 2022): 1–12. http://dx.doi.org/10.1155/2022/5717362.
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This paper examines the combined effects of ignition improvers (DMC) and EGR on the CRDI small single-cylinder diesel engine’s performance, combustion, and emissions. In this experimentation, 20% (B20) optimal mix of Prosopis juliflora oil biodiesel (PJOB) and 5 ml dimethyl carbonate (DMC) additive was used as test fuel. The fuel handling CRDI system factors such as injection pressure set at 600 bar and injection timing set to 21 (bTDC) with a compression ratio of 16 were considered for the study. For the EGR trial, 20% of the exhaust gas was recirculated under various BMEP circumstances. The test was performed with and without EGR and DMC additive conditions like (i) diesel @ 0% EGR, (ii) diesel + 5 ml DMC @ 20% EGR, (iii) B20 @ 0% EGR, and (iv) B20 + 5 ml DMC @ 20% EGR at the engine power output. The amalgamation of dimethyl carbonate (DMC) additives and EGR reduces NOx and smoke while increasing CO and HC emissions. In addition, the DMC additive and EGR improve thermal efficiency slightly. The overall clubbing of DMC additive and EGR rate indicates better performance for the selected factors than a CRDI engine with a six-hole conventional mechanical fuel injection system. The outcome of the work clearly demonstrates that both the 5 ml DMC additive and the 20% EGR rate of the B20 blend show optimum values of BTE, BSFC, and EGT of 32.93%, 0.27 kg/kw·hr, and 310.89°C, which is closer to diesel. Factors of combustion like cylinder peak pressure (CPP) and heat release rate (HRR) are 70.93 bar and 58.13 J/deg. The tailpipe exhaust of NOx and smoke is 1681 ppm and 31.30 (% vol), which is less than diesel. The HC and CO levels are 93 ppm and 0.38 (% vol), respectively, which are significantly higher than diesel fuel.
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Hameed, Rashid, Usman Akmal, Qasim S. Khan, Muhammad Ahsan Cheema, and Muhammad Rizwan Riaz. "Effect of Fibers on the Bond Behavior of Deformed Steel Bar Embedded in Recycled Aggregate Concrete." Mehran University Research Journal of Engineering and Technology 39, no. 4 (October 1, 2020): 846–58. http://dx.doi.org/10.22581/muet1982.2004.17.
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A large volume of concrete debris is being produced in many countries on the globe due to the demolition of old concrete structures and testing of concrete specimens in laboratories. One of the ways to reuse concrete debris is to produce Recycled Aggregates (RA) and use them in new concrete. In recent years, Recycled Aggregates Concrete (RAC) has experienced increasing demand in various non-structural and structural applications. In reinforced concrete structures, one of the sources of brittle failure is sudden loss of bond between reinforcing bars and concrete in anchorage zones. Therefore, for the structural application of any new kind of concrete such as fiber reinforced RAC, knowledge of bond characteristics of reinforcing bars embedded in concrete becomes essential for determining the overall structural response under different modes of loading. In this regard, this study experimentally investigated the effect of fibers on the bond stress-slip behavior of deformed steel re-bar embedded in RAC. Concrete mixes having 0, 50 and 100% RAs were prepared with and without the addition of fibers. Two types of fibers were investigated in mono form: hooked-ends steel and polypropylene fibers. The dosage of steel and polypropylene fibers was kept 40 and 4.4 kg/m3, respectively. Axial compression and standard pull-out tests were performed. Test specimens for pull-out test were prepared using deformed steel re-bars of 19mm (#6) diameter. The results of strength tests confirmed that the compressive strength of concrete is decreased by replacing Natural Aggregates (NA) with RAs. For bond behavior of steel re-bar, the results of this study showed that replacement of 50% NA with RAs did not affect the bond response of steel bar, however, 100% replacement of NA with RAs showed detrimental effect on bond stress slip behavior. The results further showed that the addition of both types of fibers made it possible to recover the loss in compressive strength, bond strengths and bond toughness occurred because of replacing NA with RAs. In case of RA concrete mixes containing hooked-ends steel fibers, strength values were found even greater than the strength values of Natural Aggregates Concrete (NAC). From the results of this study, it was found that it is possible to design a structural concrete mix using 100% RAs and steel fibers at relatively low dosage of 40kg/m3.
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Østergaard, Jeanette, Stine V. Østergaard, and Adam Fletcher. "Preferences for Simultaneous Polydrug Use." Contemporary Drug Problems 43, no. 4 (August 20, 2016): 350–68. http://dx.doi.org/10.1177/0091450916661372.
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Cross-national surveys of young adults’ simultaneous polydrug use (SPU) are rare, as measuring polydrug use requires multiple questions capturing the timing, sequence, and dosage of mixing drugs. This study proposes a new way of measuring SPU by examining how preferences for simultaneous polydrug use (PSPU) vary among club/bar-goers in two European countries, Denmark and England, typically cited as exemplars of the normalization of illegal drug use. The study considers the utility of the normalization thesis for understanding preferences for polydrug use in the European nighttime economy. An in situ survey of 1,298 young adults (18–35 years) conducted in 50 bars, pubs, and nightclubs in England and Denmark assessed sociodemographics, substance use patterns, and personal preference(s) for mixing alcohol and drug use. Multinomial regression analyses examined the relative risk of PSPU categories among those reporting drug use, according to sociodemographics, alcohol intake, frequency of intoxication, and smoking. Illicit drug use was more prevalent among young adults in England than Denmark. The difference was smallest for cannabis use: Lifetime cannabis use is 66% in England and 58% in Denmark. Lifetime cocaine use was 38% in England and 17% in Denmark. In England, young adults with drug experience preferred to mix alcohol with cocaine (65%). In Denmark, young adults with drug experience preferred to mix alcohol with cannabis (78%). In multinominal regression, Danish young adults’ educational level was associated with PSPU, whereas in England legal substance use was associated with PSPU. This study calls for a more differentiated understanding of normalization. Preferences for mixing alcohol and drug use varied significantly cross nationally (alcohol/cocaine, England; alcohol/cannabis, Denmark). Different factors are associated with PSPU in each country. In England, not Denmark, drinking behaviors appear to shape preferences for mixing alcohol with cocaine, suggesting caution should be taken when replicating harm reduction interventions.
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Dybeł, Piotr, and Milena Kucharska. "X-ray CT Investigation of Bond Mechanism in Reinforced SCC Elements of Different Placement Technology." Materials 14, no. 21 (October 20, 2021): 6236. http://dx.doi.org/10.3390/ma14216236.
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The effect of different placing methods of the self-compacting concrete (SCC) mix—from the top and from the bottom of the form—on the bond failure mechanism was investigated within the scope of this paper. Existing studies regarding the known mechanisms of bond failure do not consider the bottom-up method of concrete placing, which improves the quality of the concrete microstructure around reinforcing bars. Background tests were performed on panel elements with dimensions of 800 × 480 × 160 mm. Ribbed steel reinforcing bars with a diameter of 16 mm were used in the tests, which were placed horizontally in the forms. A pull-out method was used to investigate the bond strength. X-ray computed tomography (CT) was used as a novel and non-destructive technique that allowed a 3D insight into the bond between the rebar and the concrete after the ultimate bond stress had been reached. The results provided a clear description of the phenomena occurring during the fresh state of concrete in the vicinity of rebars (bleeding, plastic settlement, vertical density variation) and showed their significance for bond mechanisms. Finally, it was demonstrated that placing the mix from the bottom of the form resulted in the same bond failure mechanism for both bars located at the top and the bottom of the panel elements. This was translated into identical bond properties throughout the element with regard to bond stiffness and bond strength. It was found that the described and known mechanisms of bond failure are only an idealized description of the performance of the reinforcing bar-concrete joint. The analysis of the steel–concrete interface (SCI) imaging indicated that, in reality, the forming bond failure mechanisms were a complex process that could be affected by many factors.