Search results for: total phenol content
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 14069

Search results for: total phenol content

11579 Effect of Auraptene on the Enzymatic Glutathione Redox-System in Nrf2 Knockout Mice

Authors: Ludmila A. Gavriliuc, Jerry McLarty, Heather E. Kleiner, J. Michael Mathis

Abstract:

Abstract -- Background: The citrus coumarine Auraptene (Aur) is an effective chemopreventive agent, as manifested in many models of diseases and cancer. Nuclear factor erythroid 2-related factor (Nrf2) is an important regulator of genes induced by oxidative stress, such as glutathione S-transferases, heme oxygenase-1, and peroxiredoxin 1, by activating the antioxidant response element (ARE). Genetic and biochemical evidence has demonstrated that glutathione (GSH) and glutathione-dependent enzymes, glutathione reductase (GR), glutathione peroxidases (GPs), glutathione S-transferases (GSTs) are responsible for the control of intracellular reduction-oxidation status and participate in cellular adaptation to oxidative stress. The effect of Aur on the activity of GR, GPs (Se-GP and Se-iGP), and content of GSH in the liver, kidney, and spleen is insufficiently explored. Aim: Our goal was the examination of the Aur influence on the redox-system of GSH in Nrf2 wild type and Nrf2 knockout mice via activation of Nrf2 and ARE. Methods: Twenty female mice, 10 Nrf2 wild-type (WT) and 10 Nrf2 (-/-) knockout (KO), were bred and genotyped for our study. The activity of GR, Se-GP, Se-iGP, GST, G6PD, CytP450 reductase, catalase (Cat), and content of GSH were analyzed in the liver, kidney, and spleen using Spectrophotometry methods. The results of the specific activity of enzymes and the amount of GSH were analyzed with ANOVA and Spearman statistical methods. Results: Aur (200 mg/kg) treatment induced hepatic GST, GR, Se-GP activity and inhibited their activity in the spleen of mice, most likely via activation of the ARE through Nrf2. Activation in kidney Se-GP and G6PD by Aur is also controlled, apparently through Nrf2. Results of the non-parametric Spearman correlation analysis indicated the strong positive correlation between GR and G6PD only in the liver in WT control mice (r=+0.972; p < 0.005) and in the kidney KO control mice (r=+0.958; p < 0.005). The observed low content of GSH in the liver of KO mice indicated an increase in its participation in the neutralization of toxic substances with the absence of induction of GSH-dependent enzymes, such as GST, GR, Se-GP, and Se-iGP. Activation of CytP450 in kidney and spleen and Cat in the liver in KO mice probably revealed another regulatory mechanism for these enzymes. Conclusion: Thereby, obtained results testify that Aur can modulate the activity of genes and antioxidant enzymatic redox-system of GSH, responsible for the control of intracellular reduction-oxidation status.

Keywords: auraptene, glutathione, GST, Nrf2

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11578 Prevalence of Work Related Musculoskeletal Symptoms among Surgeons

Authors: Nirav P. Vaghela

Abstract:

Work-related musculoskeletal symptoms (WMS) are a major health issue in many occupations all over the world. Past research on hospital workers have mainly been focused on nurses [8] and very few studies have examined musculoskeletal symptoms among doctors in various specialties. The work of surgeons can involve high levels of mental concentration and very precise movements that can be categorized as mild-to-moderate physical demands. Design: Forty-three surgeons were enrolled in this study. To investigate musculoskeletal disorder among the surgeons we had used Standardised Nordic Questionnaire, Quick Exposure Check (QEC) and Workstyle Short Form. Result: In the current study, total 43 surgeons participants out of 30 males and 13 females. Their mean age was 42.07 ± 12.35, and the mean working years of the group were 15.14years ±9.017. On the average, they worked a total of about 8.58 h (±1.967) per day. The prevalence of work related musculoskeletal symptoms among the surgeons indicating 83.70% surgeons had atleast one joint affected while 16.30% had no symptoms at all. Conclusion: The present survey study has shown high prevalence rates of neck, back and shoulder musculoskeletal symptoms in surgeons.

Keywords: repetitive stress injury, pain, occupational hazards, disability, abneetism, physical health, quality of life

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11577 Enhanced Dielectric and Ferroelectric Properties in Holmium Substituted Stoichiometric and Non-Stoichiometric SBT Ferroelectric Ceramics

Authors: Sugandha Gupta, Arun Kumar Jha

Abstract:

A large number of ferroelectric materials have been intensely investigated for applications in non-volatile ferroelectric random access memories (FeRAMs), piezoelectric transducers, actuators, pyroelectric sensors, high dielectric constant capacitors, etc. Bismuth layered ferroelectric materials such as Strontium Bismuth Tantalate (SBT) has attracted a lot of attention due to low leakage current, high remnant polarization and high fatigue endurance up to 1012 switching cycles. However, pure SBT suffers from various major limitations such as high dielectric loss, low remnant polarization values, high processing temperature, bismuth volatilization, etc. Significant efforts have been made to improve the dielectric and ferroelectric properties of this compound. Firstly, it has been reported that electrical properties vary with the Sr/ Bi content ratio in the SrBi2Ta2O9 compsition i.e. non-stoichiometric compositions with Sr-deficient / Bi excess content have higher remnant polarization values than stoichiometic SBT compositions. With the objective to improve structural, dielectric, ferroelectric and piezoelectric properties of SBT compound, rare earth holmium (Ho3+) was chosen as a donor cation for substitution onto the Bi2O2 layer. Moreover, hardly any report on holmium substitution in stoichiometric SrBi2Ta2O9 and non-stoichiometric Sr0.8Bi2.2Ta2O9 compositions were available in the literature. The holmium substituted SrBi2-xHoxTa2O9 (x= 0.00-2.0) and Sr0.8Bi2.2Ta2O9 (x=0.0 and 0.01) compositions were synthesized by the solid state reaction method. The synthesized specimens were characterized for their structural and electrical properties. X-ray diffractograms reveal single phase layered perovskite structure formation for holmium content in stoichiometric SBT samples up to x ≤ 0.1. The granular morphology of the samples was investigated using scanning electron microscope (Hitachi, S-3700 N). The dielectric measurements were carried out using a precision LCR meter (Agilent 4284A) operating at oscillation amplitude of 1V. The variation of dielectric constant with temperature shows that the Curie temperature (Tc) decreases on increasing the holmium content. The specimen with x=2.0 i.e. the bismuth free specimen, has very low dielectric constant and does not show any appreciable variation with temperature. The dielectric loss reduces significantly with holmium substitution. The polarization–electric field (P–E) hysteresis loops were recorded using a P–E loop tracer based on Sawyer–Tower circuit. It is observed that the ferroelectric property improve with Ho substitution. Holmium substituted specimen exhibits enhanced value of remnant polarization (Pr= 9.22 μC/cm²) as compared to holmium free specimen (Pr= 2.55 μC/cm²). Piezoelectric co-efficient (d33 values) was measured using a piezo meter system (Piezo Test PM300). It is observed that holmium substitution enhances piezoelectric coefficient. Further, the optimized holmium content (x=0.01) in stoichiometric SrBi2-xHoxTa2O9 composition has been substituted in non-stoichiometric Sr0.8Bi2.2Ta2O9 composition to obtain further enhanced structural and electrical characteristics. It is expected that a new class of ferroelectric materials i.e. Rare Earth Layered Structured Ferroelectrics (RLSF) derived from Bismuth Layered Structured Ferroelectrics (BLSF) will generate which can be used to replace static (SRAM) and dynamic (DRAM) random access memories with ferroelectric random access memories (FeRAMS).

Keywords: dielectrics, ferroelectrics, piezoelectrics, strontium bismuth tantalate

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11576 Introducing a Video-Based E-Learning Module to Improve Disaster Preparedness at a Tertiary Hospital in Oman

Authors: Ahmed Al Khamisi

Abstract:

The Disaster Preparedness Standard (DPS) is one of the elements that is evaluated by the Accreditation Canada International (ACI). ACI emphasizes to train and educate all staff, including service providers and senior leaders, on emergency and disaster preparedness upon the orientation and annually thereafter. Lack of awareness and deficit of knowledge among the healthcare providers about DPS have been noticed in a tertiary hospital where ACI standards were implemented. Therefore, this paper aims to introduce a video-based e-learning (VB-EL) module that explains the hospital’s disaster plan in a simple language which will be easily accessible to all healthcare providers through the hospital’s website. The healthcare disaster preparedness coordinator in the targeted hospital will be responsible to ensure that VB-EL is ready by 25 April 2019. This module will be developed based on the Kirkpatrick evaluation method. In fact, VB-EL combines different data forms such as images, motion, sounds, text in a complementary fashion which will suit diverse learning styles and individual learning pace of healthcare providers. Moreover, the module can be adjusted easily than other tools to control the information that healthcare providers receive. It will enable healthcare providers to stop, rewind, fast-forward, and replay content as many times as needed. Some anticipated limitations in the development of this module include challenges of preparing VB-EL content and resistance from healthcare providers.

Keywords: Accreditation Canada International, Disaster Preparedness Standard, Kirkpatrick evaluation method, video-based e-learning

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11575 The ‘Quartered Head Technique’: A Simple, Reliable Way of Maintaining Leg Length and Offset during Total Hip Arthroplasty

Authors: M. Haruna, O. O. Onafowokan, G. Holt, K. Anderson, R. G. Middleton

Abstract:

Background: Requirements for satisfactory outcomes following total hip arthroplasty (THA) include restoration of femoral offset, version, and leg length. Various techniques have been described for restoring these biomechanical parameters, with leg length restoration being the most predominantly described. We describe a “quartered head technique” (QHT) which uses a stepwise series of femoral head osteotomies to identify and preserve the centre of rotation of the femoral head during THA in order to ensure reconstruction of leg length, offset and stem version, such that hip biomechanics are restored as near to normal as possible. This study aims to identify whether using the QHT during hip arthroplasty effectively restores leg length and femoral offset to within acceptable parameters. Methods: A retrospective review of 206 hips was carried out, leaving 124 hips in the final analysis. Power analysis indicated a minimum of 37 patients required. All operations were performed using an anterolateral approach by a single surgeon. All femoral implants were cemented, collarless, polished double taper CPT® stems (Zimmer, Swindon, UK). Both cemented, and uncemented acetabular components were used (Zimmer, Swindon, UK). Leg length, version, and offset were assessed intra-operatively and reproduced using the QHT. Post-operative leg length and femoral offset were determined and compared with the contralateral native hip, and the difference was then calculated. For the determination of leg length discrepancy (LLD), we used the method described by Williamson & Reckling, which has been shown to be reproducible with a measurement error of ±1mm. As a reference, the inferior margin of the acetabular teardrop and the most prominent point of the lesser trochanter were used. A discrepancy of less than 6mm LLD was chosen as acceptable. All peri-operative radiographs were assessed by two independent observers. Results: The mean absolute post-operative difference in leg length from the contralateral leg was +3.58mm. 84% of patients (104/124) had LLD within ±6mm of the contralateral limb. The mean absolute post-operative difference in offset from contralateral leg was +3.88mm (range -15 to +9mm, median 3mm). 90% of patients (112/124) were within ±6mm offset of the contralateral limb. There was no statistical difference noted between observer measurements. Conclusion: The QHT provides a simple, inexpensive yet effective method of maintaining femoral leg length and offset during total hip arthroplasty. Combining this technique with pre-operative templating or other techniques described may enable surgeons to reduce even further the discrepancies between pre-operative state and post-operative outcome.

Keywords: leg length discrepancy, technical tip, total hip arthroplasty, operative technique

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11574 Biogas from Cover Crops and Field Residues: Effects on Soil, Water, Climate and Ecological Footprint

Authors: Manfred Szerencsits, Christine Weinberger, Maximilian Kuderna, Franz Feichtinger, Eva Erhart, Stephan Maier

Abstract:

Cover or catch crops have beneficial effects for soil, water, erosion, etc. If harvested, they also provide feedstock for biogas without competition for arable land in regions, where only one main crop can be produced per year. On average gross energy yields of approx. 1300 m³ methane (CH4) ha-1 can be expected from 4.5 tonnes (t) of cover crop dry matter (DM) in Austria. Considering the total energy invested from cultivation to compression for biofuel use a net energy yield of about 1000 m³ CH4 ha-1 is remaining. With the straw of grain maize or Corn Cob Mix (CCM) similar energy yields can be achieved. In comparison to catch crops remaining on the field as green manure or to complete fallow between main crops the effects on soil, water and climate can be improved if cover crops are harvested without soil compaction and digestate is returned to the field in an amount equivalent to cover crop removal. In this way, the risk of nitrate leaching can be reduced approx. by 25% in comparison to full fallow. The risk of nitrous oxide emissions may be reduced up to 50% by contrast with cover crops serving as green manure. The effects on humus content and erosion are similar or better than those of cover crops used as green manure when the same amount of biomass was produced. With higher biomass production the positive effects increase even if cover crops are harvested and the only digestate is brought back to the fields. The ecological footprint of arable farming can be reduced by approx. 50% considering the substitution of natural gas with CH4 produced from cover crops.

Keywords: biogas, cover crops, catch crops, land use competition, sustainable agriculture

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11573 Relationship between the Ability of Accruals and Non-Systematic Risk of Shares for Companies Listed in Stock Exchange: Case Study, Tehran

Authors: Lina Najafian, Hamidreza Vakilifard

Abstract:

The present study focused on the relationship between the quality of accruals and non-systematic risk. The independent study variables included the ability of accruals, the information content of accruals, and amount of discretionary accruals considered as accruals quality measures. The dependent variable was non-systematic risk based on the Fama and French Three Factor model (FFTFM) and the capital asset pricing model (CAPM). The control variables were firm size, financial leverage, stock return, cash flow fluctuations, and book-to-market ratio. The data collection method was based on library research and document mining including financial statements. Multiple regression analysis was used to analyze the data. The study results showed that there is a significant direct relationship between financial leverage and discretionary accruals and non-systematic risk based on FFTFM and CAPM. There is also a significant direct relationship between the ability of accruals, information content of accruals, firm size, and stock return and non-systematic based on both models. It was also found that there is no relationship between book-to-market ratio and cash flow fluctuations and non-systematic risk.

Keywords: accruals quality, non-systematic risk, CAPM, FFTFM

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11572 Return to Work Following Knee Arthroplasty: A Retrospective Review in Urban Asian Population

Authors: Fiona Tan, Cheryl Tan, Thomas Wong, Remesh

Abstract:

Background: An increasing number of working adults undergo knee arthroplasty in Singapore. There is limited data concerning Southeast Asian patients returning to work (RTW) following knee replacement surgery. Our aim was to identify and study factors influencing patients' RTW following total knee arthroplasty (TKA) or unicompartmental knee arthroplasty (UKA). Methods: Patients who underwent TKA or UKA between August 2017 to March 2020 in our center were included in this study. Outcomes include RTW and duration prior to RTW. Results: 441 patients underwent TKA (295 women, 146 men, mean age 67.3 years), and 69 underwent UKA (48 women, 21 men, mean age 61.1 years). Patients who underwent TKA returned to work earlier (mean 83.7 ± 27.1 days) compared to UKA (mean 94.4 ± 42.3 days). 90.0% of TKA patients RTW compared to 95.5% who underwent UKA. Of patients who RTW, 94.3% of the TKA group returned to employment of the same nature compared to 92.9% of UKA patients. Patients who RTW were of a younger age (p = 0.03), white-collared workers (p = 0.04), and had independent preoperative ambulatory status (p <0.01). Conclusion: Younger and independently ambulating patients may have a better capacity for rehabilitation and RTW post-arthroplasty surgery.

Keywords: return to work, total knee arthroplasty, unilateral knee arthroplasty, employment

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11571 Improving Swelling Performance Using Industrial Waste Products

Authors: Mohieldin Elmashad, Salwa Yassin

Abstract:

Expansive soils regarded as one of the most problematic unsaturated formations in the Egyptian arid zones and present a great challenge in civil engineering, in general, and geotechnical engineering, in particular. Severe geotechnical complications and consequent structural damages have been arising due to an excessive and differential volumetric change upon wetting and change in water content. Different studies have been carried out concerning the swelling performance of the expansive soils using different additives including phospho-gypsum as an industrial waste product. However, this paper describes the results of a comprehensive testing programme that was carried out to investigate the effect of phospho-gypsum (PG) and sodium chloride (NaCl), as an additive mixture, on the swelling performance of constituent samples of swelling soils. The constituent samples comprise commercial bentonite collected from a natural site, mixed with different percentages of PG-NaCl mixture. The testing programme had been scoped to cover the physical and chemical properties of the constituent samples. In addition, a mineralogical study using x-ray diffraction (XRD) was performed on the collected bentonite and the mixed bentonite with PG-NaCl mixture samples. The obtained results of this study showed significant improvement in the swelling performance of the tested samples with the increase of the proposed PG-NaCl mixture content.

Keywords: expansive soils, industrial waste, mineralogical study, swelling performance, X-ray diffraction

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11570 Improvement of Vascular Oxidative Stress in Diabetic Rats by Supplementation with a Wine Pomace Product

Authors: P. Muñiz, R. Del Pino-García , M.D. Rivero-Pérez, J. García-Lomillo, M. L. González-SanJosé

Abstract:

Grape, wine and wine pomace could improve the antioxidant status in the vasculature in terms of plasma antioxidant capacity and oxidation biomarkers, partly due to their high content in polyphenols. The current study aimed to evaluate the protection of a powdered product obtained from wine pomace (WPP) against oxidative damage associated to diabetes. Streptozotocin-induced diabetic (STZ) male Wistar rats and non-diabetic control (C) rats initially weighting 300±10 mg were supplemented with 100 mg of WPP or vehicle for 4 weeks. Blood glucose levels and body weight (BW) were measured weekly. Total antioxidant capacity (TAC) assessed using the ABTS method, and F2α-Isoprostanes (F2-IsoPs) quantified by GC-MS were measured in plasma collected at the end of this experiment. Blood glucose levels tended to increase in the STZ group along the study. Supplementation maintained relatively stable during the whole experiment the blood glucose values in STZ+WPP rats. A weight loss of BW in STZ rats respect to C rats was observed after 4 weeks, whereas the decrease in BW of STZ+WPP group showed a tendency to improve at the end of the study. TAC values significantly decreased around 11% only in plasma of STZ rats. The rest of groups showed plasma TAC values about 8 mM Trolox. Increased levels of F2-IsoPs (around 25%) were also observed in plasma of STZ rats compared to the supplemented rats, revealing a protective effect of WPP against lipid peroxidation. In conclusion, 4-week supplementation with a product derived from winery by-products improved weight loss, plasma TAC, and lipid oxidation biomarkers in Type I diabetic rats.

Keywords: blood glucose, grape polyphenols, F2α-isoprostanes, type I diabetes, oxidative stress

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11569 A Framework for Successful TQM Implementation and Its Effect on the Organizational Sustainability Development

Authors: Redha Elhuni, M. Munir Ahmad

Abstract:

The main purpose of this research is to construct a generic model for successful implementation of Total Quality Management (TQM) in oil sector, and to find out the effects of this model on the organizational sustainability development (OSD) performance of Libyan oil and gas companies using the structured equation modeling (SEM) approach. The research approach covers both quantitative and qualitative methods. A questionnaire was developed in order to identify the quality factors that are seen by Libyan oil and gas companies to be critical to the success of TQM implementation. Hypotheses were developed to evaluate the impact of TQM implementation on O SD. Data analysis reveals that there is a significant positive effect of the TQM implementation on OSD. 24 quality factors are found to be critical and absolutely essential for successful TQM implementation. The results generated a structure of the TQMSD implementation framework based on the four major road map constructs (Top management commitment, employee involvement and participation, customer-driven processes, and continuous improvement culture).

Keywords: total quality management, critical success factors, oil and gas, organizational sustainability development (SD), Libya

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11568 Amino Acid Profile, Protein Digestibility, Antioxidant and Functional Properties of Protein Concentrate of Local Varieties (Kwandala, Yardass, Jeep, and Jamila) of Rice Brands from Nigeria

Authors: C. E. Chinma, S. O. Azeez, J. C. Anuonye, O. B. Ocheme, C. M. Yakubu, S. James, E. U. Ohuoba, I. A. Baba

Abstract:

There is growing interest in the use of rice bran protein in food formulation due to its hypoallergenic protein, high nutritional value and health promoting potentials. For the first time, the amino acid profile, protein digestibility, antioxidant, and functional properties of protein concentrate from some local varieties of rice bran from Nigeria were studied for possible food applications. Protein concentrates were prepared from rice bran and analysed using standard methods. Results showed that protein content of Kwandala, Yardass, Jeep, and Jamila were 69.24%, 69.97%, 68.73%, and 71.62%, respectively while total essential amino acid were 52.71, 53.03, 51.86, and 55.75g/100g protein, respectively. In vitro protein digestibility of protein concentrate from Kwandala, Yardass, Jeep and Jamila were 90.70%, 91.39%, 90.57% and 91.63% respectively. DPPH radical inhibition of protein from Kwandala, Yardass, Jeep, and Jamila were 48.15%, 48.90%, 47.56%, and 53.29%, respectively while ferric reducing ability power were 0.52, 0.55, 0.47 and 0.67mmol TE per gram, respectively. Protein concentrate from Jamila had higher onset (92.57oC) and denaturation temperature (102.13oC), and enthalpy (0.72J/g) than Jeep (91.46oC, 101.76oC, and 0.68J/g, respectively), Kwandala (90.32oC, 100.54oC and 0.57J/g, respectively), and Yardass (88.94oC, 99.45oC, and 0.51J/g, respectively). In vitro digestibility of protein from Kwandala, Yardas, Jeep, and Jamila were 90.70%, 91.39%, 90.57% and 91.63% respectively. Oil absorption capacity of Kwandala, Yardass, Jeep, and Jamila were 3.61, 3.73, 3.40, and 4.23g oil/g sample respectively, while water absorption capacity were 4.19, 4.32, 3.55 and 4.48g water/g sample, respectively. Protein concentrates had low bulk density (0.37-0.43g/ml). Protein concentrate from Jamila rice bran had the highest foam capacity (37.25%), followed by Yardass (34.20%), Kwandala (30.14%) and Jeep (28.90%). Protein concentrates showed low emulsifying and gelling capacities. In conclusion, protein concentrate prepared from these local rice bran varieties could serve as functional ingredients in food formulations and for enriching low protein foods.

Keywords: rice bran protein, amino acid profile, protein digestibility, antioxidant and functional properties

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11567 Comparison of Classical and Ultrasound-Assisted Extractions of Hyphaene thebaica Fruit and Evaluation of Its Extract as Antibacterial Activity in Reducing Severity of Erwinia carotovora

Authors: Hanan Moawad, Naglaa M. Abd EL-Rahman

Abstract:

Erwinia carotovora var. carotovora is the main cause of soft rot in potatoes. Hyphaene thebaica was studied for biocontrol of E. carotovora which inhibited growth of E. carotovora on solid medium, a comparative study of classical and ultrasound-assisted extractions of Hyphaene thebaica fruit. The use of ultrasound decreased significant the total time of treatment and increase the total amount of crude extract. The crude extract was subjected to determine the in vitro, by a bioassay technique revealed that the treatment of paper disks with ultrasound extraction of Hyphaene thebaica reduced the growth of pathogen and produced inhibition zones up to 38mm in diameter. The antioxidant activity of ultrasound-ethanolic extract of Doum fruits (Hyphaene thebaica) was determined. Data obtained showed that the extract contains the secondary metabolites such as Tannins, Saponin, Flavonoids, Phenols, Steroids, Terpenoids, Glycosides and Alkaloids.

Keywords: ultrasound, classical extract, biological control, Erwinia carotovora, Hyphaene thebaica

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11566 Evaluation of Storage Stability and Quality Parameters in Biscuit Made from Blends of Wheat, Cassava (Manihot esculenta) and Carrot (Daucus carota) Flour

Authors: Aminat. O Adelekan, Olawale T. Gbadebo

Abstract:

Biscuit is one of the most consumed cereal foods in Nigeria and research has shown that locally available tropical crops like cassava, sweet potato can be made into flour and used in the production of biscuits and other pastries. This study investigates some quality parameters in biscuits made from blends of wheat, cassava and carrot flour. The values of result of samples increased with increasing percentage substitution of cassava and carrot flour in some quality parameter like fiber, ash, gluten content, and carbohydrate. The protein content reduced significantly (P < 0.05) with increasing percentage substitution of cassava and carrot flour which ranged from 14.80% to 11.80% compared with the control sample which had 15.60%. There was a recorded significant increase (P < 0.05) in some mineral composition such as calcium, magnesium, sodium, iron, phosphorus, and vitamin A and C composition as the percentage substitution of cassava and carrot flour increased. During storage stability test, samples stored in the fridge and freezer were found to be the best storage location to preserve the sensory attributes and inhibit microbial growth when compared with storage under the sun and on the shelf. Biscuit made with blends of wheat, cassava and carrot flour can therefore serve as an alternative to biscuits made from 100% wheat flour, as they are richer in vitamin A, vitamin C, carbohydrate, dietary fiber and some essential minerals.

Keywords: biscuit, carrot, flour blends, storage

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11565 Energy Consumption Modeling for Strawberry Greenhouse Crop by Adaptive Nero Fuzzy Inference System Technique: A Case Study in Iran

Authors: Azar Khodabakhshi, Elham Bolandnazar

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Agriculture as the most important food manufacturing sector is not only the energy consumer, but also is known as energy supplier. Using energy is considered as a helpful parameter for analyzing and evaluating the agricultural sustainability. In this study, the pattern of energy consumption of strawberry greenhouses of Jiroft in Kerman province of Iran was surveyed. The total input energy required in the strawberries production was calculated as 113314.71 MJ /ha. Electricity with 38.34% contribution of the total energy was considered as the most energy consumer in strawberry production. In this study, Neuro Fuzzy networks was used for function modeling in the production of strawberries. Results showed that the best model for predicting the strawberries function had a correlation coefficient, root mean square error (RMSE) and mean absolute percentage error (MAPE) equal to 0.9849, 0.0154 kg/ha and 0.11% respectively. Regards to these results, it can be said that Neuro Fuzzy method can be well predicted and modeled the strawberry crop function.

Keywords: crop yield, energy, neuro-fuzzy method, strawberry

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11564 Polymerase Chain Reaction Analysis and Random Amplified Polymorphic DNA of Agrobacterium Tumefaciens

Authors: Abeer M. Algeblawi

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Fifteen isolates of Agrobacterium tumefaciens were obtained from crown gall samples collected from six locations (Tripoli, Alzahra, Ain-Zara, Alzawia, Alazezia in Libya) from Grape (Vitis vinifera L.), Pear (Pyrus communis L.), Peach (Prunus persica L.) and Alexandria in Egypt from Guava (Psidium guajava L.) trees, Artichoke (Cynara cardunculus L.) and Sugar beet (Beta vulgaris L.). Total DNA was extracted from the eight isolates as well as the identification of six isolates used into Polymerase Chain Reaction (PCR) analysis and Random Amplified Polymorphic DNA (RAPD) technique were used. High similarity (55.5%) was observed among the eight A. tumefaciens isolates (Agro1, Agro2, Agro3, Agro4, Agro5, Agro6, Agro7, and Agro8). The PCR amplification products were resulting from the use of two specific primers (virD2A-virD2C). Analysis induction six isolates of A. tumefaciens obtained from different hosts. A visible band was specific to A. tumefaciens of (220 bp, 224 bp) and 338 bp produced with total DNA extracted from bacterial cells.

Keywords: Agrobacterium tumefaciens, crown gall, identification, molecular characterization, PCR, RAPD

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11563 Exploring the Visual Representations of Neon Signs and Its Vernacular Tacit Knowledge of Neon Making

Authors: Brian Kwok

Abstract:

Hong Kong is well-known for its name as "the Pearl of the Orient", due to its spectacular night-view with vast amount of decorative neon lights on the streets. Neon signs are first used as the pervasive media of communication for all kinds of commercial advertising, ranging from movie theatres to nightclubs and department stores, and later appropriated by artists as medium of artwork. As a well-established visual language, it displays texts in bilingual format due to British's colonial influence, which are sometimes arranged in an opposite reading order. Research on neon signs as a visual representation is rare but significant because they are part of people’s collective memories of the unique cityscapes which associate the shifting values of people's daily lives and culture identity. Nevertheless, with the current policy to remove abandoned neon signs, their total number dramatically declines recently. The Buildings Department found an estimation of 120,000 unauthorized signboards (including neon signs) in Hong Kong in 2013, and the removal of such is at a rate of estimated 1,600 per year since 2006. In other words, the vernacular cultural values and historical continuity of neon signs will gradually be vanished if no immediate action is taken in documenting them for the purpose of research and cultural preservation. Therefore, the Hong Kong Neon Signs Archive project was established in June of 2015, and over 100 neon signs are photo-documented so far. By content analysis, this project will explore the two components of neon signs – the use of visual languages and vernacular tacit knowledge of neon makers. It attempts to answer these questions about Hong Kong's neon signs: 'What are the ways in which visual representations are used to produce our cityscapes and streetscapes?'; 'What are the visual languages and conventions of usage in different business types?'; 'What the intact knowledge are applied when producing these visual forms of neon signs?'

Keywords: cityscapes, neon signs, tacit knowledge, visual representation

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11562 Pre-Drying Effects on the Quality of Frying Oil

Authors: Hasan Yalcin, Tugba Dursun Capar

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Deep-fat frying causes desirable as well as undesirable changes in oil and potato, and changes the quality of the oil by hydrolysis, oxidation, and polymerization. The main objective of the present study was to investigate the pre-drying effects on the quality of both frying oil and potatoes. Prior to frying, potato slices (10 mm x10 mm x 30 mm) were air- dried at 60°C for 15, 30, 45, 60, 90, and 120 mins., respectively. Potato slices without the pre-drying treatment were considered as the control variable. Potato slices were fried in sunflower oil at 180°C for 5, 10, and 13 mins. The deep-frying experiments were repeated five times using the new potato slices in the same oil without oil replenishment. Samples of the fresh oil, together with those sampled at the end of successive frying operations (1th, 3th and 5th) were removed and analysed. Moisture content, colour and oil intake of the potato and colour, peroxide value (PV), free fatty acid (FFA), fatty acid composition and viscosity of the used oil were evaluated. The effect of frying time was also examined. Results show that pre-drying treatment had a significant effect on physicochemical properties and colour parameters of potato slices and frying oil. Pre-drying considerably decreased the oil absorption. The lowest oil absorption was found for the treatment that was pre-dried for 120, and fried for 5 min. The FFA levels decreased permanently for each pre-treatment throughout the frying period. All the pre-drying treatments had reached their maximum levels of FFA by the end of the frying procedures. The PV of the control and 60 min pre-dried sample decreased after the third frying. However, the PV of other samples increased constantly throughout the frying periods. Lastly, pre-drying did not affect the fatty acid composition of frying oil considerably when compared against previously unused oil.

Keywords: air-drying, deep-fat frying, moisture content oil uptake, quality

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11561 Machiavellian Language at Work: The Signs of Machiavellianism in Work-Related Interviews

Authors: Gyongyver Csapo, Andrea Czibor

Abstract:

Machiavellianism is a personality trait based on the exploitation and deception of others. Machiavellian individuals are motivated to gain and to maintain power with the help of their strategic thinking, manipulation tactics, and interpersonal skills. Consequently, Machiavellianism is treated as a personality trait that can affect an individual’s career and work-related behavior. The aim of our research is to provide a narrative psychological approach to Machiavellianism in order to get a more comprehensive picture about the attitudes, values, and work-related behaviors of Machiavellian individuals. In this study, semi-structured interviews were made with employees (N=275) about their work-related experiences. Additionally, participants completed questionnaires about their turnover intention and perceived stress. The interviews were examined with narrative psychological content analysis and thematic analyzes. Based on the thematic analysis, mentioning of two topics (recognition at work and control) were associated with Machiavellianism. Scientific narrative psychological content analysis showed a negative association between Machiavellianism and positive emotions. Turnover intention and the magnitude of perceived work-related stress showed a significant positive correlation with Machiavellianism. In this study, qualitative and quantitative methodologies were combined in order to get a deeper insight of Machiavellianism from an organizational psychological perspective. Our research can contribute to a better understanding of this personality trait and provides an excellent basis for further investigations.

Keywords: machiavellianism, narrative psychology, turnover intention, work-related stress

Procedia PDF Downloads 134
11560 Comparison of Two Neural Networks To Model Margarine Age And Predict Shelf-Life Using Matlab

Authors: Phakamani Xaba, Robert Huberts, Bilainu Oboirien

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The present study was aimed at developing & comparing two neural-network-based predictive models to predict shelf-life/product age of South African margarine using free fatty acid (FFA), water droplet size (D3.3), water droplet distribution (e-sigma), moisture content, peroxide value (PV), anisidine valve (AnV) and total oxidation (totox) value as input variables to the model. Brick margarine products which had varying ages ranging from fresh i.e. week 0 to week 47 were sourced. The brick margarine products which had been stored at 10 & 25 °C and were characterized. JMP and MATLAB models to predict shelf-life/ margarine age were developed and their performances were compared. The key performance indicators to evaluate the model performances were correlation coefficient (CC), root mean square error (RMSE), and mean absolute percentage error (MAPE) relative to the actual data. The MATLAB-developed model showed a better performance in all three performance indicators. The correlation coefficient of the MATLAB model was 99.86% versus 99.74% for the JMP model, the RMSE was 0.720 compared to 1.005 and the MAPE was 7.4% compared to 8.571%. The MATLAB model was selected to be the most accurate, and then, the number of hidden neurons/ nodes was optimized to develop a single predictive model. The optimized MATLAB with 10 neurons showed a better performance compared to the models with 1 & 5 hidden neurons. The developed models can be used by margarine manufacturers, food research institutions, researchers etc, to predict shelf-life/ margarine product age, optimize addition of antioxidants, extend shelf-life of products and proactively troubleshoot for problems related to changes which have an impact on shelf-life of margarine without conducting expensive trials.

Keywords: margarine shelf-life, predictive modelling, neural networks, oil oxidation

Procedia PDF Downloads 197
11559 An in Situ Dna Content Detection Enabled by Organic Long-persistent Luminescence Materials with Tunable Afterglow-time in Water and Air

Authors: Desissa Yadeta Muleta

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Purely organic long-persistent luminescence materials (OLPLMs) have been developed as emerging organic materials due to their simple production process, low preparation cost and better biocompatibilities. Notably, OLPLMs with afterglow-time-tunable long-persistent luminescence (LPL) characteristics enable higher-level protection applications and have great prospects in biological applications. The realization of these advanced performances depends on our ability to gradually tune LPL duration under ambient conditions, however, the strategies to achieve this are few due to the lack of unambiguous mechanisms. Here, we propose a two-step strategy to gradually tune LPL duration of OLPLMs over a wide range of seconds in water and air, by using derivatives as the guest and introducing a third-party material into the host-immobilized host–guest doping system. Based on this strategy, we develop an analysis method for deoxyribonucleic acid (DNA) content detection without DNA separation in aqueous samples, which circumvents the influence of the chromophore, fluorophore and other interferents in vivo, enabling a certain degree of in situ detection that is difficult to achieve using today’s methods. This work will expedite the development of afterglow-time-tunable OLPLMs and expand new horizons for their applications in data protection, bio-detection, and bio-sensing

Keywords: deoxyribonucliec acid, long persistent luminescent materials, water, air

Procedia PDF Downloads 76
11558 Treatment of Industrial Effluents by Using Polyethersulfone/Chitosan Membrane Derived from Fishery Waste

Authors: Suneeta Kumari, Abanti Sahoo

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Industrial effluents treatment is a major problem in the world. All wastewater treatment methods have some problems in the environment. Due to this reason, today many natural biopolymers are being used in the waste water treatment because those are safe for our environment. In this study, synthesis and characterization of polyethersulfone/chitosan membranes (Thin film composite membrane) are carried out. Fish scales are used as raw materials. Different characterization techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning electron microscope (SEM) and Thermal gravimetric analysis (TGA) are analysed for the synthesized membrane. The performance of membranes such as flux, rejection, and pore size are also checked. The synthesized membrane is used for the treatment of steel industry waste water where Biochemical oxygen demand (BOD), Chemical Oxygen Demand (COD), pH, colour, Total dissolved solids (TDS), Total suspended solids (TSS), Electrical conductivity (EC) and Turbidity aspects are analysed.

Keywords: fish scale, membrane synthesis, treatment of industrial effluents, chitosan

Procedia PDF Downloads 321
11557 Rare Earth Element (REE) Geochemistry of Tepeköy Sandstones (Central Anatolia, Turkey)

Authors: Mehmet Yavuz Hüseyinca, Şuayip Küpeli

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Sandstones from Upper Eocene - Oligocene Tepeköy formation (Member of Mezgit Group) that exposed on the eastern edge of Tuz Gölü (Salt Lake) were analyzed for their rare earth element (REE) contents. Average concentrations of ΣREE, ΣLREE (Total light rare earth elements) and ΣHREE (Total heavy rare earth elements) were determined as 31.37, 26.47 and 4.55 ppm respectively. These values are lower than UCC (Upper continental crust) which indicates grain size and/or CaO dilution effect. The chondrite-normalized REE pattern is characterized by the average ratios of (La/Yb)cn = 6.20, (La/Sm)cn = 4.06, (Gd/Lu)cn = 1.10, Eu/Eu* = 0.99 and Ce/Ce* = 0.94. Lower values of ΣLREE/ΣHREE (Average 5.97) and (La/Yb)cn suggest lower fractionation of overall REE. Moreover (La/Sm)cn and (Gd/Lu)cn ratios define less inclined LREE and almost flat HREE pattern when compared with UCC. Almost no Ce anomaly (Ce/Ce*) emphasizes that REE were originated from terrigenous material. Also depleted LREE and no Eu anomaly (Eu/Eu*) suggest an undifferentiated mafic provenance for the sandstones.

Keywords: central Anatolia, provenance, rare earth elements, REE, Tepeköy sandstone

Procedia PDF Downloads 475
11556 On Panel Data Analysis of Factors on Economic Advances in Some African Countries

Authors: Ayoola Femi J., Kayode Balogun

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In some African Countries, increase in Gross Domestic Products (GDP) has not translated to real development as expected by common-man in his household. For decades, a lot of contests on economic growth and development has been a nagging issues. The focus of this study is to analysing the effects of economic determinants/factors on economic advances in some African Countries by employing panel data analysis. The yearly (1990-2013) data were obtained from the world economic outlook database of the International Monetary Fund (IMF), for probing the effects of these variables on growth rate in some selected African countries which include: Nigeria, Algeria, Angola, Benin, Botswana, Burundi, Cape-Verde, Cameroun, Central African Republic, Chad, Republic Of Congo, Cote di’ Voire, Egypt, Equatorial-Guinea, Ethiopia, Gabon, Ghana, Guinea Bissau, Kenya, Lesotho, Madagascar, Mali, Mauritius, Morocco, Mozambique, Niger, Rwanda, Senegal, Seychelles, Sierra Leone, South Africa, Sudan, Swaziland, Tanzania, Togo, Tunisia, and Uganda. The effects of 6 macroeconomic variables on GDP were critically examined. We used 37 Countries GDP as our dependent variable and 6 independent variables used in this study include: Total Investment (totinv), Inflation (inf), Population (popl), current account balance (cab), volume of imports of goods and services (vimgs), and volume of exports of goods and services (vexgs). The results of our analysis shows that total investment, population and volume of exports of goods and services strongly affect the economic growth. We noticed that population of these selected countries positively affect the GDP while total investment and volume of exports negatively affect GDP. On the contrary, inflation, current account balance and volume of imports of goods and services’ contribution to the GDP are insignificant. The results of our analysis shows that total investment, population and volume of exports of goods and services strongly affect the economic growth. We noticed that population of these selected countries positively affect the GDP while total investment and volume of exports negatively affect GDP. On the contrary, inflation, current account balance and volume of imports of goods and services’ contribution to the GDP are insignificant. The results of this study would be useful for individual African governments for developing a suitable and appropriate economic policies and strategies. It will also help investors to understand the economic nature and viability of Africa as a continent as well as its individual countries.

Keywords: African countries, economic growth and development, gross domestic products, static panel data models

Procedia PDF Downloads 475
11555 Constructing and Circulating Knowledge in Continuous Education: A Study of Norwegian Educational-Psychological Counsellors' Reflection Logs in Post-Graduate Education

Authors: Moen Torill, Rismark Marit, Astrid M. Solvberg

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In Norway, every municipality shall provide an educational psychological service, EPS, to support kindergartens and schools in their work with children and youths with special needs. The EPS focus its work on individuals, aiming to identify special needs and to give advice to teachers and parents when they ask for it. In addition, the service also give priority to prevention and system intervention in kindergartens and schools. To master these big tasks university courses are established to support EPS counsellors' continuous learning. There is, however, a need for more in-depth and systematic knowledge on how they experience the courses they attend. In this study, EPS counsellors’ reflection logs during a particular course are investigated. The research question is: what are the content and priorities of the reflections that are communicated in the logs produced by the educational psychological counsellors during a post-graduate course? The investigated course is a credit course organized over a one-year period in two one-semester modules. The altogether 55 students enrolled in the course work as EPS counsellors in various municipalities across Norway. At the end of each day throughout the course period, the participants wrote reflection logs about what they had experienced during the day. The data material consists of 165 pages of typed text. The collaborating researchers studied the data material to ascertain, differentiate and understand the meaning of the content in each log. The analysis also involved the search for similarity in content and development of analytical categories that described the focus and primary concerns in each of the written logs. This involved constant 'critical and sustained discussions' for mutual construction of meaning between the co-researchers in the developing categories. The process is inspired by Grounded Theory. This means that the concepts developed during the analysis derived from the data material and not chosen prior to the investigation. The analysis revealed that the concept 'Useful' frequently appeared in the participants’ reflections and, as such, 'Useful' serves as a core category. The core category is described through three major categories: (1) knowledge sharing (concerning direct and indirect work with students with special needs) with colleagues is useful, (2) reflections on models and theoretical concepts (concerning students with special needs) are useful, (3) reflection on the role as EPS counsellor is useful. In all the categories, the notion of useful occurs in the participants’ emphasis on and acknowledgement of the immediate and direct link between the university course content and their daily work practice. Even if each category has an importance and value of its own, it is crucial that they are understood in connection with one another and as interwoven. It is the connectedness that gives the core category an overarching explanatory power. The knowledge from this study may be a relevant contribution when it comes to designing new courses that support continuing professional development for EPS counsellors, whether for post-graduate university courses or local courses at the EPS offices or whether in Norway or other countries in the world.

Keywords: constructing and circulating knowledge, educational-psychological counsellor, higher education, professional development

Procedia PDF Downloads 115
11554 Effect of Chemical Fertilizer on Plant Growth-Promoting Rhizobacteria in Wheat

Authors: Tessa E. Reid, Vanessa N. Kavamura, Maider Abadie, Adriana Torres-Ballesteros, Mark Pawlett, Ian M. Clark, Jim Harris, Tim Mauchline

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The deleterious effect of chemical fertilizer on rhizobacterial diversity has been well documented using 16S rRNA gene amplicon sequencing and predictive metagenomics. Biofertilization is a cost-effective and sustainable alternative; improving strategies depends on isolating beneficial soil microorganisms. Although culturing is widespread in biofertilization, it is unknown whether the composition of cultured isolates closely mirrors native beneficial rhizobacterial populations. This study aimed to determine the relative abundance of culturable plant growth-promoting rhizobacteria (PGPR) isolates within total soil DNA and how potential PGPR populations respond to chemical fertilization in a commercial wheat variety. It was hypothesized that PGPR will be reduced in fertilized relative to unfertilized wheat. Triticum aestivum cv. Cadenza seeds were sown in a nutrient depleted agricultural soil in pots treated with and without nitrogen-phosphorous-potassium (NPK) fertilizer. Rhizosphere and rhizoplane samples were collected at flowering stage (10 weeks) and analyzed by culture-independent (amplicon sequence variance (ASV) analysis of total rhizobacterial DNA) and -dependent (isolation using growth media) techniques. Rhizosphere- and rhizoplane-derived microbiota culture collections were tested for plant growth-promoting traits using functional bioassays. In general, fertilizer addition decreased the proportion of nutrient-solubilizing bacteria (nitrate, phosphate, potassium, iron and, zinc) isolated from rhizocompartments in wheat, whereas salt tolerant bacteria were not affected. A PGPR database was created from isolate 16S rRNA gene sequences and searched against total soil DNA, revealing that 1.52% of total community ASVs were identified as culturable PGPR isolates. Bioassays identified a higher proportion of PGPR in non-fertilized samples (rhizosphere (49%) and rhizoplane (91%)) compared to fertilized samples (rhizosphere (21%) and rhizoplane (19%)) which constituted approximately 1.95% and 1.25% in non-fertilized and fertilized total community DNA, respectively. The analyses of 16S rRNA genes and deduced functional profiles provide an in-depth understanding of the responses of bacterial communities to fertilizer; this study suggests that rhizobacteria, which potentially benefit plants by mobilizing insoluble nutrients in soil, are reduced by chemical fertilizer addition. This knowledge will benefit the development of more targeted biofertilization strategies.

Keywords: bacteria, fertilizer, microbiome, rhizoplane, rhizosphere

Procedia PDF Downloads 307
11553 Factors Influencing Milk Yield, Quality, and Revenue of Dairy Farms in Southern Vietnam

Authors: Ngoc-Hieu Vu

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Dairy production in Vietnam is a relatively new agricultural activity and milk production increased remarkably in recent years. Smallholders are still the main drivers for this development, especially in the southern part of the country. However, information on the farming practices is very limited. Therefore, this study aimed to determine factors influencing milk yield and quality (milk fat, total solids, solids-not-fat, total number of bacteria, and somatic cell count) and revenue of dairy farms in Southern Vietnam. The collection of data was at the farm level; individual animal records were unavailable. The 539 studied farms were located in the provinces Lam Dong (N=111 farms), Binh Duong (N=69 farms), Long An (N=174 farms), and Ho Chi Minh city (N=185 farms). The dataset included 9221 monthly test-day records of the farms from January 2013 to May 2015. Seasons were defined as rainy and dry. Farms sizes were classified as small (< 10 milking cows), medium (10 to 19 milking cows) and large (≥ 20 milking cows). The model for each trait contained year-season and farm region-farm size as subclass fixed effects, and individual farm and residual as random effects. Results showed that year-season, region, and farm size were determining sources of variation affecting all studied traits. Milk yield was higher in dry than in rainy seasons (P < 0.05), while it tended to increase from years 2013 to 2015. Large farms had higher yields (445.6 kg/cow) than small (396.7 kg/cow) and medium (428.0 kg/cow) farms (P < 0.05). Small farms, in contrast, were superior to large farms in terms of milk fat, total solids, solids-not-fat, total number of bacteria, and somatic cell count than large farms (P < 0.05). Revenue per cow was higher in large compared with medium and small farms. In conclusion, large farms achieved higher milk yields and revenues per cow, while small farms were superior in milk quality. Overall, milk yields were low and better training, financial support and marketing opportunities for farmers are needed to improve dairy production and increase farm revenues in Southern Vietnam.

Keywords: farm size, milk yield and quality, season, Southern Vietnam

Procedia PDF Downloads 362
11552 Performance Analysis of Arithmetic Units for IoT Applications

Authors: Nithiya C., Komathi B. J., Praveena N. G., Samuda Prathima

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At present, the ultimate aim in digital system designs, especially at the gate level and lower levels of design abstraction, is power optimization. Adders are a nearly universal component of today's integrated circuits. Most of the research was on the design of high-speed adders to execute addition based on various adder structures. This paper discusses the ideal path for selecting an arithmetic unit for IoT applications. Based on the analysis of eight types of 16-bit adders, we found out Carry Look-ahead (CLA) produces low power. Additionally, multiplier and accumulator (MAC) unit is implemented with the Booth multiplier by using the low power adders in the order of preference. The design is synthesized and verified using Synopsys Design Compiler and VCS. Then it is implemented by using Cadence Encounter. The total power consumed by the CLA based booth multiplier is 0.03527mW, the total area occupied is 11260 um², and the speed is 2034 ps.

Keywords: carry look-ahead, carry select adder, CSA, internet of things, ripple carry adder, design rule check, power delay product, multiplier and accumulator

Procedia PDF Downloads 118
11551 Water-Bentonite Interaction of Green Pellets through Micro-Structural Analysis

Authors: Satyananda Patra, Venugopal Rayasam

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The quality of pellets produced is affected by quality and type of green pellets, amount of addition of binders and fluxing agents along with the provided firing conditions. The green pellet quality depends upon chemistry, mineralogy and granulometry of fines used for pellet making, the feed size, its moisture content and porosity. During firing of green pellets, ingredients present within reacts to form different phases and microstructure. So in turn, physical and metallurgical properties of pellets are influenced by amount and type of binder and flux addition, induration time and temperature. During iron making process, the metallurgical properties of fired pellets are decided by the type and amount of these phases and their chemistry. Green pelletizing and induration studies have been already carried out with magnetite and hematite ore fines but for Indian iron ores of high alumina content showing different pelletizing characters, these studies cannot be directly interpreted. The main objective of proposed research work is to understand the green pelletizing process and determine the water bentonite interaction at different levels. Swelling behavior of bentonite and microstructure of the green pellet are investigated. Conversion of iron ore fines into pellets, the key raw material and process variables that influence the pellet quality needs to be identified and a correlation should be established between them.

Keywords: iron ore, pelletization, binders, green pellets, microstructure

Procedia PDF Downloads 314
11550 Influence of Recycled Concrete Aggregate Content on the Rebar/Concrete Bond Properties through Pull-Out Tests and Acoustic Emission Measurements

Authors: L. Chiriatti, H. Hafid, H. R. Mercado-Mendoza, K. L. Apedo, C. Fond, F. Feugeas

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Substituting natural aggregate with recycled aggregate coming from concrete demolition represents a promising alternative to face the issues of both the depletion of natural resources and the congestion of waste storage facilities. However, the crushing process of concrete demolition waste, currently in use to produce recycled concrete aggregate, does not allow the complete separation of natural aggregate from a variable amount of adhered mortar. Given the physicochemical characteristics of the latter, the introduction of recycled concrete aggregate into a concrete mix modifies, to a certain extent, both fresh and hardened concrete properties. As a consequence, the behavior of recycled reinforced concrete members could likely be influenced by the specificities of recycled concrete aggregates. Beyond the mechanical properties of concrete, and as a result of the composite character of reinforced concrete, the bond characteristics at the rebar/concrete interface have to be taken into account in an attempt to describe accurately the mechanical response of recycled reinforced concrete members. Hence, a comparative experimental campaign, including 16 pull-out tests, was carried out. Four concrete mixes with different recycled concrete aggregate content were tested. The main mechanical properties (compressive strength, tensile strength, Young’s modulus) of each concrete mix were measured through standard procedures. A single 14-mm-diameter ribbed rebar, representative of the diameters commonly used in the domain of civil engineering, was embedded into a 200-mm-side concrete cube. The resulting concrete cover is intended to ensure a pull-out type failure (i.e. exceedance of the rebar/concrete interface shear strength). A pull-out test carried out on the 100% recycled concrete specimen was enriched with exploratory acoustic emission measurements. Acoustic event location was performed by means of eight piezoelectric transducers distributed over the whole surface of the specimen. The resulting map was compared to existing data related to natural aggregate concrete. Damage distribution around the reinforcement and main features of the characteristic bond stress/free-end slip curve appeared to be similar to previous results obtained through comparable studies carried out on natural aggregate concrete. This seems to show that the usual bond mechanism sequence (‘chemical adhesion’, mechanical interlocking and friction) remains unchanged despite the addition of recycled concrete aggregate. However, the results also suggest that bond efficiency seems somewhat improved through the use of recycled concrete aggregate. This observation appears to be counter-intuitive with regard to the diminution of the main concrete mechanical properties with the recycled concrete aggregate content. As a consequence, the impact of recycled concrete aggregate content on bond characteristics seemingly represents an important factor which should be taken into account and likely to be further explored in order to determine flexural parameters such as deflection or crack distribution.

Keywords: acoustic emission monitoring, high-bond steel rebar, pull-out test, recycled aggregate concrete

Procedia PDF Downloads 172