Search results for: oxygen reduction reaction (ORR)

Authors: Ndana Mohammed, Abdullahi Musa Sabo

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The oils used in this work were extracted from seeds of Ricinuscommunis, Heaveabrasiliensis, Gossypiumhirsutum, Azadirachtaindica, Glycin max and Jatrophacurcasby solvent extraction method using n-hexane, and gave the yield of 48.00±0.00%, 44.30±0.52%, 45.50±0.64%, 47.60±0.51%, 41.50±0.32% and 46.50±0.71% respectively. However these feed stocks are highly challenging to trans-esterification reaction because they were found to contain high amount of free fatty acids (FFA) (6.37±0.18, 17.20±0.00, 6.14±0.05, 8.60±0.14, 5.35±0.07, 4.24±0.02mgKOH/g) in order of the above. As a result, two-stage trans-esterification reactions process was used to produce biodiesel; Acid esterification was used to reduce high FFA to 1% or less, and the second stage involve the alkaline trans-esterification/optimization of process condition to obtain high yield quality biodiesel. The salient features of this study include; characterization of oils using AOAC, AOCS standard methods to reveal some properties that may determine the viability of sample seeds as potential feed stocks for biodiesel production, such as acid value, saponification value, Peroxide value, Iodine value, Specific gravity, Kinematic viscosity, and free fatty acid profile. The optimization of process parameters in biodiesel production was investigated. Different concentrations of alkaline catalyst (KOH) (0.25, 0.5, 0.75, 1.0 and 1.50w/v, methanol/oil molar ratio (3:1, 6:1, 9:1, 12:1, and 15:1), reaction temperature (500 C, 550 C, 600 C, 650 C, 700 C), and the rate of stirring (150 rpm,225 rpm,300 rpm and 375 rpm) were used for the determination of optimal condition at which maximum yield of biodiesel would be obtained. However, while optimizing one parameter other parameters were kept fixed. The result shows the optimal biodiesel yield at a catalyst concentration of 1%, methanol/oil molar ratio of 6:1, except oil from ricinuscommunis which was obtained at 9:1, the reaction temperature of 650 C was observed for all samples, similarly the stirring rate of 300 rpm was also observed for all samples except oil from ricinuscommunis which was observed at 375 rpm. The properties of biodiesel fuel were evaluated and the result obtained conformed favorably to ASTM and EN standard specifications for fossil diesel and biodiesel. Therefore biodiesel fuel produced can be used as substitute for fossil diesel. The work also reports the result of the study on the evaluation of the effect of the biodiesel storage on its physicochemical properties to ascertain the level of deterioration with time. The values obtained for the entire samples are completely out of standard specification for biodiesel before the end of the twelve months test period, and are clearly degraded. This suggests the biodiesels from oils of Ricinuscommunis, Heaveabrasiliensis, Gossypiumhirsutum, Azadirachtaindica, Glycin max and Jatrophacurcascannot be stored beyond twelve months.

Keywords: biodiesel, characterization, esterification, optimization, transesterification

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Authors: Lu Si, Jie Yu, Shasha Li, Jun Ma, Lei Luo, Qingbo Wu, Yongqi Ma, Zhengji Liu

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Instance selection (IS) technique is used to reduce the data size to improve the performance of data mining methods. Recently, to process very large data set, several proposed methods divide the training set into some disjoint subsets and apply IS algorithms independently to each subset. In this paper, we analyze the limitation of these methods and give our viewpoint about how to divide and conquer in IS procedure. Then, based on fast condensed nearest neighbor (FCNN) rule, we propose a large data sets instance selection method with MapReduce framework. Besides ensuring the prediction accuracy and reduction rate, it has two desirable properties: First, it reduces the work load in the aggregation node; Second and most important, it produces the same result with the sequential version, which other parallel methods cannot achieve. We evaluate the performance of FCNN-MR on one small data set and two large data sets. The experimental results show that it is effective and practical.

Keywords: instance selection, data reduction, MapReduce, kNN

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Authors: Betelhem M. Negede, Maarten Voors, Hugo De Groote, Bart Minten

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Farmers in Ethiopia produce most of their own food during one agricultural season per year. Therefore, they need to use on-farm storage technologies to bridge the lean season and benefit from price arbitrage. Maize stored using traditional storage bags offer no protection from insects and molds, leading to high storage losses. In Ethiopia access to and use of modern storage technologies are still limited, restraining farmers to benefit from local maize price fluctuations. We used a randomized controlled trial among 871 maize farmers to evaluate the impacts of Purdue Improved Crop Storage (PICS) bags, also known as hermetic bags, on storage losses, and especially on behavioral changes with respect to consumption, marketing, and income among maize farmers in Ethiopia. This study builds upon the limited previous experimental research that has tried to understand farmers’ grain storage and post-harvest losses and identify mechanisms behind the persistence of these challenges. Our main hypothesis is that access to PICS bags allows farmers to increase production, storage and maize income. Also delay the length of maize storage, reduce maize post-harvest losses and improve their food security. Our results show that even though farmers received only three PICS bags that represent 10percent of their total maize stored, they delay their length of maize storage for sales by two weeks. However, we find no treatment effect on maize income, suggesting that the arbitrage of two weeks is too small. Also, we do not find any reduction in storage losses due to farmers’ reaction by selling early and by using cheap and readily available but potentially harmful storage chemicals. Looking at the heterogeneity treatment effects between the treatment variable and highland and lowland villages, we find a decrease in the percentage of maize stored by 4 percent in the highland villages. This confirms that location specific factors, such as agro-ecology and proximity to markets are important factors that influence whether and how much of the harvest a farmer stores. These findings highlight the benefits of hermetic storage bags, by allowing farmers to make inter-temporal arbitrage and by reducing potential health risks from storage chemicals. The main policy recommendation that emanates from our study is that postharvest losses reduction throughout the whole value chain is an important pathway to food and income security in Sub-Saharan Africa (SSA). However, future storage loss interventions with hermetic storage technologies should take into account the agro-ecology of the study area and quantify storage losses beyond farmers self-reported losses, such as the count and weigh method. Finally, studies on hermetic storage technologies indicate positive impacts on post-harvest losses and in improving food security, but the adoption and use of these technologies is currently still low in SSA. Therefore, future works on the scaling up of hermetic bags, should consider reasons why farmers only use PICS bags to store grains for consumption, which is usually related to a safety-first approach or due to lack of incentives (higher price from maize not treated with chemicals), and no grain quality check.

Keywords: arbitrage, PICS hermetic bags, post-harvest storage loss, RCT

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Authors: Yi-cheng Chen, Ming-jum Guo, Yang-ru Chen

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Background and Objective: For safety and fair during basketball competition, FIBA proposes the definite level of physical functions in wooden surface system (WSS). There are existing various between different systems in indoor-stadium, so the aim of this study want to know how many effects in different WSS, especially for effects of ground reaction force(GRF) when player jumped. Materials and Methods: 12 participants acted counter-movement jump (CMJ) on 7 different surfaces, include 6 WSSs by 3 types rubber shock absorber pad (SAP) on cross or parallel fixed, and 1 rigid ground. GRFs of takeoff and landing had been recorded from an AMTI force platform when all participants acted vertical CMJs by counter-balance design. All data were analyzed using the one-way ANOVA to evaluate whether the test variable differed significantly between surfaces. The significance level was set at α=0.05. Results: There were non-significance in GRF between surfaces when participants taken off. For GRF of landing, we found WSS with cross fixed SAP are harder than parallel fixed. Although there were also non-significance when participant was landing on cross or parallel fixed surfaces, but there have test variable differed significantly between WSS with parallel fixed to rigid ground. In the study, landing to WSS with the hardest SAP, the GRF also have test variable differed significantly to other WSS. Conclusion: Although official basketball competition is in the WSS certificated by FIBA, there are also exist the various in GRF under takeoff or landing, any player must to warm-up before game starting. Especially, there is unsafe situation when play basketball on uncertificated WSS.

Keywords: wooden surface system, counter-movement jump, ground reaction force, shock absorber pad

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Authors: Y. S. Shen, B. H. Liao

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This study aimed to develop the design equation of a laminar-falling-film-slurry (LFFS) type photoreactor for the treatment of organic wastewaters containing isopropyl alcohol (IPA) by VUV-based advanced oxidation processes (AOPs). The photoreactor design equations were established by combining with the chemical kinetics of the photocatalytic system, light absorption model within the photoreactor, and was used to predict the decomposition of IPA in aqueous solutions in the photoreactors of different geometries at various operating conditions (volumetric flow rate, oxidants, catalysts, solution pH values, UV light intensities, and initial concentration of pollutants) to verify its rationality and feasibility. By the treatment of the LFFS-VUV only process, it was found that the decomposition rates of IPA in aqueous solutions increased with the increase of volumetric flow rate, VUV light intensity, dosages of TiO2 and H2O2. The removal efficiencies of IPA by photooxidation processes were in the order: VUV/H2O2>VUV/TiO2/H2O2>VUV/TiO2>VUV only. In VUV, VUV/H2O2, VUV/TiO2/H2O2 processes, integrating with the reaction kinetic equations of IPA, the mass conservation equation and the linear light source model, the photoreactor design equation can reasonably to predict reaction behaviors of IPA at various operating conditions and to describe the concentration distribution profiles of IPA within photoreactors.The results of this research can be useful basis for the future application of the homogeneous and heterogeneous VUV-based advanced oxidation processes.

Keywords: isopropyl alcohol, photoreactor design, VUV, AOPs

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Authors: Baqir Khawari

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This study has been undertaken to investigate the impact of remittances on household poverty and inequality using OLS and Logit Models with a strictly multi-random sampling method. The result of the OLS model reveals that if the per capita international remittances increase by 1%, then it is estimated that the per capita income will increase by 0.071% and 0.059% during 2019/20 and 2020/21, respectively. In addition, a 1% increase in external remittances results in a 0.0272% and 0.025% reduction in per capita depth of poverty and a 0.0149% and 0.0145% decrease in severity of poverty during 2019/20 and 2020/21, respectively. It is also shown that the effect of external remittances on poverty is greater than internal remittances. In terms of inequality, the result represents that remittances reduced the Gini coefficient by 2% and 7% during 2019/20 and 2020/21, respectively. Further, it is bold that COVID-19 negatively impacts the amount of received remittances by households, thus resulting in a reduction in the size of the effect of remittances. Therefore, a concerted effort of effective policies and governance and international assistance is imperative to address this prolonged problem.

Keywords: migration, remittances, poverty, inequality, COVID-19, Afghanistan

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Authors: Thomas L. McCullough, John D. Hague, Marylesa M. Howard, Matthew K. Kiser, Michael A. Mazur, Lance K. McLean, Johanna L. Turk

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Radiological search and mapping depends on the successful recognition of anomalies in large data sets which contain varied and dynamic backgrounds. We present a new algorithmic approach for real-time anomaly detection which is resistant to common detector imperfections, avoids the limitations of a source template library and provides immediate, and easily interpretable, user feedback. This algorithm is based on a continuous wavelet transform for variance reduction and evaluates the deviation between a foreground measurement and a local background expectation using methods from linear algebra. We also present a technique for recognizing and visualizing spectrally similar clusters of data. This technique uses Laplacian Eigenmap Manifold Learning to perform dimensional reduction which preserves the geometric "closeness" of the data while maintaining sensitivity to outlying data. We illustrate the utility of both techniques on real-world data sets.

Keywords: radiological search, radiological mapping, radioactivity, radiation protection

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Authors: I. Dangeard, S. Meineri, M. Dupré

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large body of research on energy consumption reveals that regular information on energy consumption produces a positive effect on behavior. The present research aims to test this feedback paradigm on waste management. A small-scale experiment on residual household waste was performed in a large french urban area, in partnership with local authorities, as part of the development of larger-scale project. A two-step door-to-door recruitment scheme led to 85 households answering a questionnaire. Among them, 54 accepted to participate in a study on waste (second step). Participants were then randomly assigned to one of the 3 experimental conditions : self-reported feedback on curbside waste, external feedback on waste weight based on information technologies, and no feedback for the control group. An additional control group was added, including households who were not requested to answer the questionnaire. Household residual waste was collected every week, and tags on curbside bins fed a database with waste weight of households. The feedback period lasted 14 weeks (february-may 2014). Quantitative data on waste weight were analysed, including these 14 weeks and the 7 previous weeks. Households were then contacted by phone in order to confirm the quantitative results. Regarding the recruitment questionnaire, results revealed high pro-environmental attitude on the NEP scale, high recycling behavior level and moderate level of source reduction behavior on the adapted 3R scale, but no statistical difference between the 3 experimental groups. Regarding the feedback manipulation paradigm, waste weight reveals important differences between households, but doesn't prove any statistical difference between the experimental conditions. Qualitative phone interviews confirm that recycling is a current practice among participants, whereas source reduction of waste is not, and mainly appears as a producer problem of packaging limitation. We conclude that triggering waste prevention behaviors among recycling households involves long-term feedback and should promote benchmarking, in order to clearly set waste reduction as an objective to be managed through feedback figures.

Keywords: eco-feedback, household waste, waste reduction, experimental research

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Authors: Chuyi Ye, Minsang Kim, Cheol-Hee Moon

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The organic light emitting diode(OLED), is a potential organic optical functional materials which is considered as the next generation display technology with the advantages such as all-solid state, ultra-thin thickness, active luminous and flexibility. Due to the development of polymer-inorganic substrate, it becomes possible to achieve the flexible OLED display. However the organic light-emitting material is very sensitive to the oxygen and water vapor, and the encapsulation requires water vapor transmission rate(WVTR) and oxygen transmission rate(OTR) as lower as 10-6 g/(m2.d) and 10-5 cm3/(m2.d) respectively. In current situation, the rigorous WVTR and OTR have restricted the application of the OLED display. Traditional epoxy/getter or glass frit approaches, which have been widely applied on glass-substrate-based devices, are not suitable for transparent flexible organic devices, and mechanically flexible thin-film approaches are required. To ensure the OLED’s lifetime, the encapsulation material of the OLED package is very important. In this paper, a low melting point alloy(LMPA)-epoxy mixture in the encapsulation process is introduced. There will be a phase separation when the mixture is heated to the melting of LMPA and the formation of the double line structure between two substrates: the alloy barrier has extremely low WVTR and OTR and the epoxy fills the potential tiny cracks. In our experiment, the PI film is chosen as a flexible transparent substrate, and Mo and Cu are deposited on the PI film successively. Then the two metal layers are photolithographied to the sealing pattern line. The Mo is a transition layer between the PI film and Cu, at the same time, the Cu has a good wettability with the LMPA(Sn-58Bi). At last, pattern is printed with LMPA layer and applied voltage, the gathering Joule heat melt the LMPA and form the double line structure and the OLED package is sealed in the same time. In this research, the double-line encapsulating structure of LMPA and epoxy on the PI film is manufactured for the flexible OLED encapsulation, and in this process it is investigated whether the encapsulation satisfies the requirement of WVTR and OTR for the flexible OLED.

Keywords: encapsulation, flexible, low melting point alloy, OLED

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Authors: I. A. Yola

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Impact of poultry dropping, cow dung and rumen content on utilization and proximate composition of Oreochromis niliticus, Clarias gariepinus and Cyprinus capio in a polyculture system were studied. The research was conducted over a period of 52 weeks. Poultry droppings (PD), cow dung (CD) and rumen content (RC) were applied at three levels 30g,60g and 120g/m2/week, 25g,50g and 100g/m2/week and 22g, 44g and 88g/m2/week treatment, respectively. The control only conventional feed with 40% CP without manure application was used. Physicochemical and biological properties measured were higher in manure pond than control. The difference was statistically significant (P < 0.05) between and within treatments with exception of temperature with a combined mean of 27.900C. The water was consistently alkaline with mean values for pH of 6.61, transparency 22.6cm, conductivity 35.00µhos/cm, dissolved oxygen 4.6 mg/l, biological oxygen demand 2.8mg/l, nitrate and phosphates 0.9mg/l and 0.35mg/l, respectively. The three fish species increase in weight with increased manure rate, with a higher value in PD treatment on C. capio record 340g, O. niloticus weighed 310g and C. gariepinus 280g over the experimental period. Fishes fed supplementary diet (control) grew bigger with highest value on C. capio (685g) O. niloticus (620g) and then C. gariepinus (526g). The differences were statistically significant (P < 0.05). The result of whole body proximate analysis indicated that various manures and rates had an irregular pattern on the protein and ash gain per 100g of fish body weight gain. The combined means for whole fish carcass protein, lipids, moisture, ash and gross energy were 11.84, 2.43, 74.63, 3.00 and 109.9 respectively. The notable exceptions were significant (p < 0.05) increases in body fat and gross energy gains in all fish species accompanied by decreases in percentages of moisture as manure rates increased. Survival percentage decreases from 80% to 70%. It is recommended to use poultry dropping as manure/feeds at the rate of 120kg/ha/week for good performances in polyculture.

Keywords: organic manure, Nile tilapia, African mud fish, common carp, proximate composition

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Authors: Moulay Driss Mellaoui, Abdallah Imjjad, Rachid Boutiddar, Haydar Mohammad-Salim, Nivedita Acharjee, Hassan Bourzi, Souad El Issami, Khalid Abbiche, Hanane Zejli

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We have investigated the underlying molecular processes involved in the [3+2] cycloaddition (32CA) reactions between N-methyl-C-(2-furyl) nitrone and three acetylene derivatives: 4b, 5b, and 6b. For this investigation, we utilized molecular electron density theory (MEDT) and density functional theory (DFT) methods at the B3LYP-D3/6 31G (d) computational level. These 32CA reactions, which exhibit a zwitterionic (zw-type) nature, proceed through a one-step mechanism with activation enthalpies ranging from 8.80 to 14.37 kcal mol−1 in acetonitrile and ethanol solvents. When the nitrone reacts with phenyl methyl propiolate (4b), two regioisomeric pathways lead to the formation of two products: P1,5-4b and P1,4-4b. On the other hand, when the nitrone reacts with dimethyl acetylene dicarboxylate (5b) and acetylene dicarboxylic acid (but-2-ynedioic acid) (6b), it results in the formation of a single product. Through topological analysis, we can categorize the nitrone as a zwitterionic three-atom component (TAC). Furthermore, the analysis of conceptual density functional theory (CDFT) indices classifies the 32CA reactions of the nitrone with 4b, 5b, and 6b as forward electron density flux (FEDF) reactions. The study of bond evolution theory (BET) reveals that the formation of new C-C and C-O covalent bonds does not initiate in the transition states, as the intermediate stages of these reactions display pseudoradical centers of the atoms already involved in bonding.

Keywords: 4-isoxazoline, DFT/B3LYP-D3, regioselectivity, cycloaddition reaction, MEDT, ELF

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Authors: Tatjana Kadifkova Panovska, Svetlana Kulevanova, Blagica Jovanova

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Biological systems possess the ability to neutralize the excess of reactive oxygen species (ROS) and to protect cells from destructive alterations. However, many pathological conditions (cardiovascular diseases, autoimmune disorders, cancer) are associated with inflammatory processes that generate an excessive amount of reactive oxygen species (ROS) that shift the balance between endogenous antioxidant systems and free oxygen radicals in favor of the latter, leading to oxidative stress. Therefore, an additional source of natural compounds with antioxidant properties that will reduce the amount of ROS in cells is much needed despite their broad utilization; many plant species remain largely unexplored. Therefore, the purpose of the present study is to investigate the antioxidant activity of twenty-five selected medicinal and aromatic plant species. The antioxidant activity of the ethanol extracts was evaluated with in vitro assays: 2,2’-diphenyl-1-pycryl-hydrazyl (DPPH), ferric reducing antioxidant power (FRAP), non-site-specific- (NSSOH) and site-specific hydroxyl radical-2-deoxy-D-ribose degradation (SSOH) assays. The Folin-Ciocalteu method and AlCl3 method were performed to determine total phenolic content (TPC) and total flavonoid content (TFC). All examined plant extracts manifested antioxidant activity to a different extent. Cinnamomum verum J.Presl bark and Ocimum basilicum L. Herba demonstrated strong radical scavenging activity and reducing power with the DPPH and FRAP assay, respectively. Additionally, significant hydroxyl scavenging potential and metal chelating properties were observed using the NSSOH and SSOH assays. Furthermore, significant variations were determined in the total polyphenolic content (TPC) and total flavonoid content (TFC), with Cinnamomum verum and Ocimum basilicum showing the highest amount of total polyphenols. The considerably strong radical scavenging activity, hydroxyl scavenging potential and reducing power for the species mentioned above suggest of a presence of highly bioactive phytochemical compounds, predominantly polyphenols. Since flavonoids are the most abundant group of polyphenols that possess a large number of available reactive OH groups in their structure, it is considered that they are the main contributors to the radical scavenging properties of the examined plant extracts. This observation is supported by the positive correlation between the radical scavenging activity and the total polyphenolic and flavonoid content obtained in the current research. The observations from the current research nominate Cinnamomum verum bark and Ocimum basilicum herba as potential sources of bioactive compounds that could be utilized as antioxidative additives in the food and pharmaceutical industries. Moreover, the present study will help the researchers as basic data for future research in exploiting the hidden potential of these important plants that have not been explored so far.

Keywords: ethanol extracts, radical scavenging activity, reducing power, total polyphenols.

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Authors: Welder A. Baldassini, Jon J. Ramsey, Marcos R. Chiaratti, Amália S. Chaves, Renata H. Branco, Sarah F. M. Bonilha, Dante P. D. Lanna

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With increased production costs there is a need for animals that are more efficient in terms of meat production. In this context, the role of mitochondrial DNA (mtDNA) on physiological processes in liver, muscle and adipose tissues may account for inter-animal variation in energy expenditures and heat production. The purpose this study was to investigate if the amounts of mtDNA in liver, muscle and adipose tissue (subcutaneous and visceral depots) of Nellore bulls are associated with residual feed intake (RFI) and estimated heat production (EHP). Eighteen animals were individually fed in a feedlot for 90 days. RFI values were obtained by regression of dry matter intake (DMI) in relation to average daily gain (ADG) and mid-test metabolic body weight (BW). The animals were classified into low (more efficient) and high (less efficient) RFI groups. The bulls were then randomly distributed in individual pens where they were given excess feed twice daily to result in 5 to 10% orts for 90 d with diet containing 15% crude protein and 2.7 Mcal ME/kg DM. The heart rate (HR) of bulls was monitored for 4 consecutive days and used for calculation of EHP. Electrodes were fitted to bulls with stretch belts (POLAR RS400; Kempele, Finland). To calculate oxygen pulse (O2P), oxygen consumption was obtained using a facemask connected to the gas analyzer (EXHALYZER, ECOMedics, Zurich, Switzerland) and HR were simultaneously measured for 15 minutes period. Daily oxygen (O2) consumption was calculated by multiplying the volume of O2 per beat by total daily beats. EHP was calculated multiplying O2P by the average HR obtained during the 4 days, assuming 4.89 kcal/L of O2 to measure daily EHP that was expressed in kilocalories/day/kilogram metabolic BW (kcal/day/kg BW0.75). Blood samples were collected between days 45 and 90th after the beginning of the trial period in order to measure the concentration of hemoglobin and hematocrit. The bulls were slaughtered in an experimental slaughter house in accordance with current guidelines. Immediately after slaughter, a section of liver, a portion of longissimus thoracis (LT) muscle, plus a portion of subcutaneous fat (surrounding LT muscle) and portions of visceral fat (kidney, pelvis and inguinal fat) were collected. Samples of liver, muscle and adipose tissues were used to quantify mtDNA copy number per cell. The number of mtDNA copies was determined by normalization of mtDNA amount against a single copy nuclear gene (B2M). Mean of EHP, hemoglobin and hematocrit of high and low RFI bulls were compared using two-sample t-tests. Additionally, the one-way ANOVA was used to compare mtDNA quantification considering the mains effects of RFI groups. We found lower EHP (83.047 vs. 97.590 kcal/day/kgBW0.75; P < 0.10), hemoglobin concentration (13.533 vs. 15.108 g/dL; P < 0.10) and hematocrit percentage (39.3 vs. 43.6 %; P < 0.05) in low compared to high RFI bulls, respectively, which may be useful traits to identify efficient animals. However, no differences were observed between the mtDNA content in liver, muscle and adipose tissue of Nellore bulls with high and low RFI.

Keywords: bioenergetics, Bos indicus, feed efficiency, mitochondria

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Authors: Dan Akesson, Gauthaman Kuzhanthaivelu, Martin Bohlen, Sunil K. Ramamoorthy

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Bioplastics can be defined as polymers derived partly or completely from biomass. Bioplastics can be biodegradable such as polylactic acid (PLA) and polyhydroxyalkonoates (PHA); or non-biodegradable (biobased polyethylene (bio-PE), polypropylene (bio-PP), polyethylene terephthalate (bio-PET)). The usage of such bioplastics is expected to increase in the future due to new found interest in sustainable materials. At the same time, these plastics become a new type of waste in the recycling stream. Most countries do not have separate bioplastics collection for it to be recycled or composted. After a brief introduction of bioplastics such as PLA in the UK, these plastics are once again replaced by conventional plastics by many establishments due to lack of commercial composting. Recycling companies fear the contamination of conventional plastic in the recycling stream and they said they would have to invest in expensive new equipment to separate bioplastics and recycle it separately. This project studies what happens when bioplastics contaminate conventional plastics. Three commonly used conventional plastics were selected for this study: polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET). In order to simulate contamination, two biopolymers, either polyhydroxyalkanoate (PHA) or thermoplastic starch (TPS) were blended with the conventional polymers. The amount of bioplastics in conventional plastics was either 1% or 5%. The blended plastics were processed again to see the effect of degradation. The results from contamination showed that the tensile strength and the modulus of PE was almost unaffected whereas the elongation is clearly reduced indicating the increase in brittleness of the plastic. Generally, it can be said that PP is slightly more sensitive to the contamination than PE. This can be explained by the fact that the melting point of PP is higher than for PE and as a consequence, the biopolymer will degrade more quickly. However, the reduction of the tensile properties for PP is relatively modest. Impact strength is generally a more sensitive test method towards contamination. Again, PE is relatively unaffected by the contamination but for PP there is a relatively large reduction of the impact properties already at 1% contamination. PET is polyester, and it is, by its very nature, more sensitive to degradation than PE and PP. PET also has a much higher melting point than PE and PP, and as a consequence, the biopolymer will quickly degrade at the processing temperature of PET. As for the tensile strength, PET can tolerate 1% contamination without any reduction of the tensile strength. However, when the impact strength is examined, it is clear that already at 1% contamination, there is a strong reduction of the properties. The thermal properties show the change in the crystallinity. The blends were also characterized by SEM. Biphasic morphology can be seen as the two polymers are not truly blendable which also contributes to reduced mechanical properties. The study shows that PE is relatively robust against contamination, while polypropylene (PP) is sensitive and polyethylene terephthalate (PET) can be quite sensitive towards contamination.

Keywords: bioplastics, contamination, recycling, waste management

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Authors: Ankita Jadon, Sidi Souvi, Nathalie Girault, Denis Petitprez

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Safety requirements for Generation IV nuclear reactor designs, especially the new generation sodium-cooled fast reactors (SFR) require a risk-informed approach to model severe accidents (SA) and their consequences in case of outside release. In SFRs, aerosols are produced during a core disruptive accident when primary system sodium is ejected into the containment and burn in contact with the air; producing sodium aerosols. One of the key aspects of safety evaluation is the in-containment sodium aerosol behavior and their interaction with fission products. The study of the effects of sodium fires is essential for safety evaluation as the fire can both thermally damage the containment vessel and cause an overpressurization risk. Besides, during the fire, airborne fission product first dissolved in the primary sodium can be aerosolized or, as it can be the case for fission products, released under the gaseous form. The objective of this work is to study the interactions between sodium aerosols and fission products (Iodine, toxic and volatile, being the primary concern). Sodium fires resulting from an SA would produce aerosols consisting of sodium peroxides, hydroxides, carbonates, and bicarbonates. In addition to being toxic (in oxide form), this aerosol will then become radioactive. If such aerosols are leaked into the environment, they can pose a danger to the ecosystem. Depending on the chemical affinity of these chemical forms with fission products, the radiological consequences of an SA leading to containment leak tightness loss will also be affected. This work is split into two phases. Firstly, a method to theoretically understand the kinetics and thermodynamics of the heterogeneous reaction between sodium aerosols and fission products: I2 and HI are proposed. Ab-initio, density functional theory (DFT) calculations using Vienna ab-initio simulation package are carried out to develop an understanding of the surfaces of sodium carbonate (Na2CO3) aerosols and hence provide insight on its affinity towards iodine species. A comprehensive study of I2 and HI adsorption, as well as bicarbonate formation on the calculated lowest energy surface of Na2CO3, was performed which provided adsorption energies and description of the optimized configuration of adsorbate on the stable surface. Secondly, the heterogeneous reaction between (I2)g and Na2CO3 aerosols were investigated experimentally. To study this, (I2)g was generated by heating a permeation tube containing solid I2, and, passing it through a reaction chamber containing Na2CO3 aerosol deposit. The concentration of iodine was then measured at the exit of the reaction chamber. Preliminary observations indicate that there is an effective uptake of (I2)g on Na2CO3 surface, as suggested by our theoretical chemistry calculations. This work is the first step in addressing the gaps in knowledge of in-containment and atmospheric source term which are essential aspects of safety evaluation of SFR SA. In particular, this study is aimed to determine and characterize the radiological and chemical source term. These results will then provide useful insights for the developments of new models to be implemented in integrated computer simulation tool to analyze and evaluate SFR safety designs.

Keywords: iodine adsorption, sodium aerosols, sodium cooled reactor, DFT calculations, sodium carbonate

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Authors: Mohammed Nasir Kajama, Ngozi Claribelle Nwogu, Edward Gobina

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Pt/γ-Al2O3 membrane catalysts were prepared via an evaporative-crystallization deposition method. The obtained Pt/γ-Al2O3 catalyst activity was tested after characterization (SEM-EDAX observation, BET measurement, permeability assessment) in the catalytic oxidation of selected volatile organic compound (VOC) i.e. propane, fed in mixture of oxygen. The VOC conversion (nearly 90%) obtained by varying the operating temperature showed that flow-through membrane reactor might do better in the abatement of VOCs.

Keywords: VOC combustion, flow-through membrane reactor, platinum supported alumina catalysts

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Authors: I. Yordanova, H. Kolev, S. Todorova, Z. Cherkezova-Zheleva

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Catalysis plays a key role in solving many environmental problems by establishing efficient catalytic systems for environmental protection and reducing emissions of greenhouse gases from industry. Volatile organic compounds are major air pollutants. There are several ways to dispose of emissions like - adsorption, condensation, absorption, bio-filtration, thermal, catalytic, plasma and ultraviolet oxidation. The catalytic oxidation has more advantages over other methods. For example - lower energy consumption; the concentration of the organic contaminant may be low or may vary within wide limits. Catalysts for complete oxidation of VOCs can be classified into three categories: noble metal, metal oxides or supported metal oxides and mixture of noble metals and metal oxides. Most of the catalysts for the complete catalytic oxidation are based on Pt, Pd, Rh or a combination thereof. The oxides of the transition metal are one of the alternatives to noble metal catalysts for these reactions. They are less active at low temperatures, but at higher - their activity is similar. The properties of the catalyst depend on the distribution of the active phase, the medium type of the pre-treatment, the interaction between the active phase and the support and the interaction between the active phase and the reaction medium. Supported mono-component Mn and bi-component Mn-Co systems are examined in present study. The samples are prepared using co-precipitation method. SiO2 (Aerosil) is used as a support. The studied samples were precipitated by NH4OH. The synthesized samples were characterized by XRD, XPS, TPR and tested in the catalytic reaction of complete oxidation of n-hexane, propane, methanol, ethanol and propanol.

Keywords: catalytic oxidation, Co-Mn oxide, oxidation of hydrocarbons and alcohols, environmental protection

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Authors: Diego Giuseppe Romano, Gianvito Apuleo, Jiri Duda

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Mobility is one of the most important societal needs for amusement, business activities and health. Thus, transport needs are continuously increasing, with the consequent traffic congestion and pollution increase. Aeronautic effort aims at smarter infrastructures use and in introducing greener concepts. A possible solution to address the abovementioned topics is the development of Small Air Transport (SAT) system, able to guarantee operability from today underused airfields in an affordable and green way, helping meanwhile travel time reduction, too. In the framework of Horizon2020, EU (European Union) has funded the Clean Sky 2 SAT TA (Transverse Activity) initiative to address market innovations able to reduce SAT operational cost and environmental impact, ensuring good levels of operational safety. Nowadays, most of the key technologies to improve passenger comfort and to reduce community noise, DOC (Direct Operating Costs) and pilot workload for SAT have reached an intermediate level of maturity TRL (Technology Readiness Level) 3/4. Thus, the key technologies must be developed, validated and integrated on dedicated ground and flying aircraft demonstrators to reach higher TRL levels (5/6). Particularly, SAT TA focuses on the integration at aircraft level of the following technologies [1]: 1)    Low-cost composite wing box and engine nacelle using OoA (Out of Autoclave) technology, LRI (Liquid Resin Infusion) and advance automation process. 2) Innovative high lift devices, allowing aircraft operations from short airfields (< 800 m). 3) Affordable small aircraft manufacturing of metallic fuselage using FSW (Friction Stir Welding) and LMD (Laser Metal Deposition). 4)       Affordable fly-by-wire architecture for small aircraft (CS23 certification rules). 5) More electric systems replacing pneumatic and hydraulic systems (high voltage EPGDS -Electrical Power Generation and Distribution System-, hybrid de-ice system, landing gear and brakes). 6) Advanced avionics for small aircraft, reducing pilot workload. 7) Advanced cabin comfort with new interiors materials and more comfortable seats. 8) New generation of turboprop engine with reduced fuel consumption, emissions, noise and maintenance costs for 19 seats aircraft. (9) Alternative diesel engine for 9 seats commuter aircraft. To address abovementioned market innovations, two different platforms have been designed: Reference and Green aircraft. Reference aircraft is a virtual aircraft designed considering 2014 technologies with an existing engine assuring requested take-off power; Green aircraft is designed integrating the technologies addressed in Clean Sky 2. Preliminary integration of the proposed technologies shows an encouraging reduction of emissions and operational costs of small: about 20% CO₂ reduction, about 24% NO_x reduction, about 10 db (A) noise reduction at measurement point and about 25% DOC reduction. Detailed description of the performed studies, analyses and validations for each technology as well as the expected benefit at aircraft level are reported in the present paper.

Keywords: affordable, European, green, mobility, technologies development, travel time reduction

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Authors: Xiao L Dai, Wen X Wei, Shuo Wang, Jia B Li, Yan Wei

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Heavy oil pollution generated from both natural and anthropogenic sources could cause significant damages to the ecological environment, due to the toxicity of some of its constituents. Nowadays, microbial remediation is becoming a promising technology to treat oil pollution owing to its low cost and prevention of secondary pollution; microorganisms are key players in the process. Compared to the free microorganisms, immobilized microorganisms possess several advantages, including high metabolic activity rates, strong resistance to toxic chemicals and natural competition with the indigenous microorganisms, and effective resistance to washing away (in open water system). Many immobilized microorganisms have been successfully used for bioremediation of heavy oil pollution. Considering the broad choices, low cost, simple process, large specific surface area and less impact on microbial activity, modified zeolite were selected as a bio-carrier for bacteria immobilization. Three strains of heavy oil-degrading bacteria Bacillus sp. DL-13, Brevibacillus sp. DL-1 and Acinetobacter sp. DL-34 were immobilized on the modified zeolite under mild conditions, and the bacterial load (bacteria /modified zeolite) was 1.12 mg/g, 1.11 mg/g, and 1.13 mg/g, respectively. SEM results showed that the bacteria mainly adsorbed on the surface or punctured in the void of modified zeolite. The heavy oil degradation efficiency of immobilized bacteria was 62.96%, higher than that of the free bacteria (59.83%). The heavy oil degradation process of immobilized bacteria accords with the first-order reaction equation, and the reaction rate constant is 0.1483 d⁻¹, which was significantly higher than the free bacteria (0.1123 d⁻¹), suggesting that the immobilized bacteria can rapidly start up the heavy oil degradation and has a high activity of heavy oil degradation. The results suggested that immobilized bacteria are promising technology for bioremediation of oil pollution.

Keywords: heavy oil pollution, microbial remediation, modified zeolite, immobilized bacteria

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Authors: Diego De Castro Rodrigues, Marcelo Lisboa Rocha, Daniela M. De Q. Trevisan, Marcos Dias Da Conceicao, Gabriel Rosa, Rommel M. Barbosa

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The use of association rules algorithms within data mining is recognized as being of great value in the knowledge discovery in databases. Very often, the number of rules generated is high, sometimes even in databases with small volume, so the success in the analysis of results can be hampered by this quantity. The purpose of this research is to present a method for reducing the quantity of rules generated with association algorithms. Therefore, a computational algorithm was developed with the use of a Weka Application Programming Interface, which allows the execution of the method on different types of databases. After the development, tests were carried out on three types of databases: synthetic, model, and real. Efficient results were obtained in reducing the number of rules, where the worst case presented a gain of more than 50%, considering the concepts of support, confidence, and lift as measures. This study concluded that the proposed model is feasible and quite interesting, contributing to the analysis of the results of association rules generated from the use of algorithms.

Keywords: data mining, association rules, rules reduction, artificial intelligence

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Authors: Yasaman Tohidi, Shidvash Vakilipour, Saeed Ebadi Tavallaee, Shahin Vakilipoor Takaloo, Hossein Amiri

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The numerical modeling is performed to study the effects of N₂ addition to the fuel stream on the flame structure and temperature distribution of methane-air swirl diffusion flames with different swirl intensities. The Open source Field Operation and Manipulation (OpenFOAM) has been utilized as the computational tool. Flamelet approach along with modified k-ε model is employed to model the flame characteristics.  The results indicate that the presence of N₂ in the fuel stream leads to the flame temperature reduction. By increasing of swirl intensity, the flame structure changes significantly. The flame has a conical shape in low swirl intensity; however, it has an hour glass-shape with a shorter length in high swirl intensity. The effects of N₂ dilution decrease the flame length in all swirl intensities; however, the rate of reduction is more noticeable in low swirl intensity.

Keywords: swirl diffusion flame, N2 dilution, OpenFOAM, swirl intensity

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Authors: Juan S. Vera, Miguel A. Gomez, Omar Gelvez

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Water is Earth's most valuable resource, and the lack of it is currently a critical problem in today’s society. Non-treated wastewaters contribute to this situation, especially those coming from industrial activities, as they reduce the quality of the water bodies, annihilating all kind of life and bringing disease to people in contact with them. An effective solution for this problem is distillation, which removes most contaminants. However, this approach must also be energetically efficient in order to appeal to the industry. In this endeavour, most water distillation treatments fail, with the exception of the Mechanical Vapor Compression (MVC) distillation system, which has a great efficiency due to energy input by a compressor and the latent heat exchange. This paper presents the process of design, construction, and evaluation of a Mechanical Vapor Compression (MVC) distillation system for the main Colombian poultry company Avidesa Macpollo SA. The system will be located in the principal slaughterhouse in the state of Santander, and it will work along with the Gas Energy Mixing system (GEM) to treat the wastewaters from the plant. The main goal of the MVC distiller, rarely used in this type of application, is to reduce the chlorides, Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD) levels according to the state regulations since the GEM cannot decrease them enough. The MVC distillation system works with three components, the evaporator/condenser heat exchanger where the distillation takes place, a low-pressure compressor which gives the energy to create the temperature differential between the evaporator and condenser cavities and a preheater to save the remaining energy in the distillate. The model equations used to describe how the compressor power consumption, heat exchange area and distilled water are related is based on a thermodynamic balance and heat transfer analysis, with correlations taken from the literature. Finally, the design calculations and the measurements of the installation are compared, showing accordance with the predictions in distillate production and power consumption, changing the temperature difference of the evaporator/condenser.

Keywords: mechanical vapor compression, distillation, wastewater, design, construction, evaluation

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Authors: Seyed Reza Mirdehghan, Mohammad Reza Haeri Yazdi

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In this paper, the stability and the performance of a two-degree-of-freedom robot under an interaction with a unknown environment has been investigated. The time when the robot returns to its initial position after an interaction and the primary resistance of the robot against the impact must be reduced. Thus, the applied torque on the motor will be reduced. The impedance control is an appropriate method for robot control in these conditions. The stability of the robot at interaction moment was transformed to be a robust stability problem. The dynamic of the unknown environment was modeled as a weight function and the stability of the robot under an interaction with the environment has been investigated using the robust control concept. To improve the performance of the system, a force controller has been designed which the normalized impedance after interaction has been reduced. The resistance of the robot has been considered as a normalized cost function and its value was 0.593. The results has showed reduction of resistance of the robot against impact and the reduction of convergence time by lower than one second.

Keywords: impedance control, control system, robots, interaction

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Authors: Asmaa M. Fahim

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In this elucidation, we synthesized different heterocyclic compounds attached to Benzene sulfonamide moiety via (E)-N-(4-(3-(4-bromophenyl)acryloyl)phenyl)-4-methyl benzene sulfonamide which is obtained from Nucleophilic substitution reaction between 4-methylbenzene sulfonyl chloride and 1-(4-aminophenyl)ethan-1-one in pyridine to get N-(4-acetyl phenyl)-4-methyl benzenesulfonamide which reacted 4-bromobenzal dehyde undergoes aldol condensation in NaOH to afford the corresponding chalchone 4. Moreover, the reactivity of chalchone 4 showed several active methylene derivatives utilized the pressurized microwave irradiation as a green energy resource. Chalcone 4 was allowed to react with ethyl cyanoacetate and acetylacetone, respectively, at 70 °C with pressure under microwave reaction condition to afford the 5-cyano-6-oxo-1,2,5,6-tetrahydropyridin-2-yl)-4-methylbenzenesulfonamide 6 and N-(4'-acetyl-4''-bromo-5'-oxo-2',3',4',5'-tetrahydro-[1,1':3',1''-terphenyl]-4-yl)-4-methylbenzenesulfonamide 8 derivatives. Moreover, the reactivity of this sulphonamide chalchone with NH2NH2 in EtOH and acetic acid, which gave 2,5-dihydro-1H-imidazol-4-yl)-4-methyl benzenesulfonamide, 1H-pyrazol-3-yl)-4-methyl and reactivity with NH2OH.HCl gave isoxazol-3-yl)-4-methylbenzenesulfonamide derivatives. The synthesized compounds were screened for their ADME properties and directed to antitumor activity on HepG2 hepatocellular carcinoma and MCF-7 breast cancer and exhibited excellent behavior against standard drugs; these results were confirmed through molecular simulations with different proteins. Additionally, the Density Functional Theory analysis of optimized structures investigated their physical descriptors, FMO, ESP and MEP, which correlated with biological evaluation.

Keywords: synthesis, green chemistry, antitumor activity, DFT study

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Authors: Muhammad Faiz Liew Abdullah, Bhagwan Das, Nor Shahida, Abdul Fattah Chandio

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This study presents the designed features of Graphical User Interface (GUI) for chromatic dispersion (CD) reduction using digital signal processing (DSP) techniques. GUI is specially designed for windows platform. The obtained simulation results from matlab are presented via this GUI. After importing results from matlab in GUI, It will present your work on any windows7 and onwards versions platforms without matlab software. First part of the GUI contains the research methodology block diagram and in the second part, output for each stage is shown in separate reserved area for the result display. Each stage of methodology has the captions to display the results. This GUI will be very helpful during presentations instead of making slides this GUI will present all your work easily in the absence of other software’s such as Matlab, Labview, MS PowerPoint. GUI is designed using C programming in MS Visio Studio.

Keywords: Matlab simulation results, C programming, MS VISIO studio, chromatic dispersion

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Authors: Mohamrd Ali Alrabib

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Sandstones samples were selected from cores of seven wells ranging in depth from 5040 to 7181.4 ft. The dominant authigenic cement phase is quartz overgrowth cement (up to 13% by volume) and this is the major mechanism for porosity reduction. Late stage carbonate cements (siderite and dolomite/ferroan dolomite) are present and these minerals infill intergranular porosity and, therefore, further reduce porosity and probably permeability. Authigenic clay minerals are represented by kaolinite, illite, and grain coating clay minerals. Kaolinite occurs as booklet and vermicular forms. Minor amounts of illite were noted in the studied samples, which commonly block pore throats, thereby reducing permeability. Primary porosity of up to 26.5% is present. Secondary porosity (up to 17%) is also present as a result of feldspar dissolution. The high intergranular volume (IGV) of the sandstones indicates that mechanical and chemical compaction played a more important role than cementation of porosity loss.

Keywords: authigenic minerals, porosity types, porosity reduction, mamuniyat sandstone reservoir

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Authors: Ajit Brindhaban

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Background and Purpose: Computed Tomography (CT) scans have become the largest source of radiation in radiological imaging. The purpose of this study was to compare the quality of pediatric Computed Tomography (CT) images reconstructed using Filtered Back Projection (FBP) with images reconstructed using different strengths of Iterative Reconstruction (IR) technique, and to perform a feasibility study to assess the use of IR techniques as a dose reduction tool. Materials and Methods: An anthropomorphic phantom representing a 5-year old child was scanned, in two stages, using a Siemens Somatom CT unit. In stage one, scans of the head, chest and abdomen were performed using standard protocols recommended by the scanner manufacturer. Images were reconstructed using FBP and 5 different strengths of IR. Contrast-to-Noise Ratios (CNR) were calculated from average CT number and its standard deviation measured in regions of interest created in the lungs, bone, and soft tissues regions of the phantom. Paired t-test and the one-way ANOVA were used to compare the CNR from FBP images with IR images, at p = 0.05 level. The lowest strength value of IR that produced the highest CNR was identified. In the second stage, scans of the head was performed with decreased mA(s) values relative to the increase in CNR compared to the standard FBP protocol. CNR values were compared in this stage using Paired t-test at p = 0.05 level. Results: Images reconstructed using IR technique had higher CNR values (p < 0.01.) in all regions compared to the FBP images, at all strengths of IR. The CNR increased with increasing IR strength of up to 3, in the head and chest images. Increases beyond this strength were insignificant. In abdomen images, CNR continued to increase up to strength 5. The results also indicated that, IR techniques improve CNR by a up to factor of 1.5. Based on the CNR values at strength 3 of IR images and CNR values of FBP images, a reduction in mA(s) of about 20% was identified. The images of the head acquired at 20% reduced mA(s) and reconstructed using IR at strength 3, had similar CNR as FBP images at standard mA(s). In the head scans of the phantom used in this study, it was demonstrated that similar CNR can be achieved even when the mA(s) is reduced by about 20% if IR technique with strength of 3 is used for reconstruction. Conclusions: The IR technique produced better image quality at all strengths of IR in comparison to FBP. IR technique can provide approximately 20% dose reduction in pediatric head CT while maintaining the same image quality as FBP technique.

Keywords: filtered back projection, image quality, iterative reconstruction, pediatric computed tomography imaging

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Authors: Yaniv Knop, Alva Peled

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Over the past few years there has been a growing interest in the development of Portland Composite Cement, by partial replacement of the clinker with mineral additives. The motivations to reduce the clinker content are threefold: (1) Ecological - due to lower emission of CO2 to the atmosphere; (2) Economical - due to cost reduction; and (3) Scientific\Technology – improvement of performances. Among the mineral additives being used and investigated, limestone is one of the most attractive, as it is considered natural, available, and with low cost. The goal of the research is to develop green cement, by partial replacement of the clinker with limestone powder while improving the performances of the cement paste. This work studied blended cements with three limestone powder particle diameters: smaller than, larger than, and similarly sized to the clinker particle. Blended cement with limestone consisting of one particle size distribution and limestone consisting of a combination of several particle sizes were studied and compared in terms of hydration rate, hydration degree, and water demand to achieve normal consistency. The performances of these systems were also compared with that of the original cement (without added limestone). It was found that the ability to replace an active material with an inert additive, while achieving improved performances, can be obtained by increasing the packing density of the cement-based particles. This may be achieved by replacing the clinker with limestone powders having a combination of several different particle size distributions. Mathematical and physical models were developed to simulate the setting history from initial to final setting time and to predict the packing density of blended cement with limestone having different sizes and various contents. Besides the effect of limestone, as inert additive, on the packing density of the blended cement, the influence of the limestone particle size on three different chemical reactions were studied; hydration of the cement, carbonation of the calcium hydroxide and the reactivity of the limestone with the hydration reaction products. The main results and developments will be presented.

Keywords: packing density, hydration degree, limestone, blended cement

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Authors: A. Benhadji, R. Maachi

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Environmental protection has become a major economic development issues. Indeed, the environment has become both market growth factor and element of competition. It is now an integral part of all industrial strategies. Ecosystem protection is based on the reduction of the pollution load in the treatment of liquid waste. The physicochemical techniques are commonly used which a transfer of pollution is generally found. Alternative to physicochemical methods is the use of microorganisms for cleaning up the waste waters. The objective of this research is the evaluation of the effects of exogenous added Pseudomonas strains on pollutants biodegradation. The influence of the critical parameters such as inoculums concentration and duration treatment are studied. The results show that Pseudomonas putida is found to give a maximum reduction in chemical organic demand (COD) in 4 days of incubation. However, toward to protect biological pollution of environment, the treatment is achieved by electro coagulation process using aluminium electrodes. The results indicate that this process allows disinfecting the water and improving the electro coagulated sludge quality.

Keywords: tannery, pseudomonas, biological treatment, electrocoagulation process, sludge quality

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Authors: Jong Hoon Kim, Hyun-Soo Lee, Moonseo Park, Min Jeong, Inbeom Lee

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Pre-construction is essential in achieving the success of a construction project. Due to the early involvement of project participants in the construction phase, project managers are able to plan ahead and solve issues well in advance leading to the success of the project and the satisfaction of the client. This research utilizes quantitative data derived from construction management projects in order to identify the relationship between pre-construction, construction schedule, and client satisfaction. A total of 65 construction projects and 93 clients were investigated for this research in an attempt to identify (a) the relationship between pre-construction and schedule reduction, and (b) pre-construction and client loyalty. Based on the quantitative analysis, this research was able to establish a negative correlation based on 65 construction projects between pre-construction and project schedule existed. This finding represents that the more pre-construction is performed for a certain project, the overall construction schedule decreased. Then, to determine the relationship between pre-construction and client satisfaction, Net Promoter Score (NPS) of 93 clients from the 65 projects was utilized. Pre-construction and NPS was further analyzed and a positive correlation was found between the two. This infers that clients tend to be more satisfied with projects with higher ratio of pre-construction than those projects with less pre-construction.

Keywords: client loyalty, NPS, pre-construction, schedule reduction

Procedia PDF Downloads 365