Search results for: surface plasmon

Authors: F. Javier Benitez, Francisco J. Real, Juan Luis Acero, Francisco Casas

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Three emerging contaminants (amitriptyline hydrochloride, methyl salicylate and 2-phenoxyethanol) frequently found in waste-waters were selected to be individually degraded in ultra-pure water by the combined advanced oxidation process constituted by UV radiation and chlorine. The influence of pH, initial chlorine concentration and nature of the contaminants was firstly explored. The trend for the reactivity of the selected compounds was deduced: amitriptyline hydrochloride > methyl salicylate > 2-phenoxyethanol. A later kinetic study was carried out and focused on the specific evaluation of the first-order rate constants and the determination of the partial contribution to the global reaction of the direct photochemical pathway and the radical pathway. A comparison between the rate constant values among photochemical experiments without and with the presence of Cl₂ reveals a clear increase in the oxidation efficiency of the combined process with respect to the photochemical reaction alone. In a second stage, the simultaneous oxidation of mixtures of the selected contaminants in several types of water (ultrapure water, surface water from a reservoir, and two secondary effluents) was also performed by the same combination UV/Cl₂ under more realistic operating conditions. The efficiency of this combined system UV/Cl₂ was compared to other oxidants such as the UV/S₂O₈^2- and UV/H₂O₂ AOPs. Results confirmed that the UV/Cl₂ system provides higher elimination efficiencies among the AOPs tested.

Keywords: emerging contaminants, UV/chlorine advanced oxidation process, amitriptyline, methyl salicylate, 2-phenoxyethanol, chlorination, photolysis

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Authors: Ahokas Mikko, Taskila Sanna, Varrio Kalle, Tanskanen Juha

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The present research aimed at the development of an energy efficient process for the concentration of starchy waste waters. The selected principle is mechanical vapor recompression evaporation (MVR) which leads to concentrated solid material and evaporated water phase. Evaporation removes water until a certain viscosity limit is reached. Materials with high viscosity cannot be concentrated using standard evaporators due to limitations of pumps and other constraints, such as wetting. Control of viscosity is thus essential for efficient evaporation. This applies especially to fluids in which due starch or other compounds the viscosity tends to increase via removal of water. In the present research, the effect of enzymes on evaporation of highly viscous starch industry waste waters was investigated. Wastewater samples were received from starch industry at pH of 4.8. Response surface methodology (RSM) was applied for the investigation of factor effects on the behaviour of concentrate during evaporation. The RSM was prepared using quadratic face-centered central composite design (CCF). The evaporation performance was evaluated by monitoring the viscosity of fluid during processing. Based on viscosity curves, the addition of glucoamylase reduced the viscosity during evaporation. This assumption was confirmed by CCF, suggesting that the use of starch decomposing glucoamylase allowed evaporation of the starchy wastewater to a relatively high total solid concentration without a detrimental increase in the viscosity. The results suggest that use of enzymes for reduction of viscosity during the evaporation allows more effective concentration of the wastewater and thereby recovery of potable water.

Keywords: viscous, wastewater, treatment, evaporation, concentration

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Authors: Riaan Kleyn

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Mass wine production companies across the globe are provided with grapes from winegrowers that predominantly utilize mechanical harvesting machines to harvest wine grapes. Mechanical harvesting accelerates the rate at which grapes are harvested, allowing grapes to be delivered faster to meet the demands of wine cellars. The disadvantage of the mechanical harvesting method is the inclusion of material-other-than-grapes (MOG) in the harvested wine grape loads arriving at the cellar which degrades the quality of wine that can be produced. Currently, wine cellars do not have a method to determine the amount of MOG present within wine grape loads. This paper seeks to find an optimal computer vision method capable of detecting the amount of MOG within a wine grape load. A MOG detection method will encourage winegrowers to deliver MOG-free wine grape loads to avoid penalties which will indirectly enhance the quality of the wine to be produced. Traditional image segmentation methods were compared to deep learning segmentation methods based on images of wine grape loads that were captured at a wine cellar. The Mask R-CNN model with a ResNet-50 convolutional neural network backbone emerged as the optimal method for this study to determine the amount of MOG in an image of a wine grape load. Furthermore, a statistical analysis was conducted to determine how the MOG on the surface of a grape load relates to the mass of MOG within the corresponding grape load.

Keywords: computer vision, wine grapes, machine learning, machine harvested grapes

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Authors: C. S. Saini

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The composite flour blend consisting of corn, pearl millet, black gram and wheat bran in the ratio of 80:5:10:5 was taken to prepare the extruded product and their effect on physical properties of extrudate was studied. The extrusion process was conducted in laboratory by using twin screw extruder. The physical characteristics evaluated include lateral expansion, bulk density, water absorption index, water solubility index, rehydration ratio and moisture retention. The Central Composite Rotatable Design (CCRD) was used to decide the level of processing variables i.e. feed moisture content (%), screw speed (rpm), and barrel temperature (oC) for the experiment. The data obtained after extrusion process were analyzed by using response surface methodology. A second order polynomial model for the dependent variables was established to fit the experimental data. The numerical optimization studies resulted in 127°C of barrel temperature, 246 rpm of screw speed, and 14.5% of feed moisture as optimum variables to produce acceptable extruded product. The responses predicted by the software for the optimum process condition resulted in lateral expansion 126 %, bulk density 0.28 g/cm3, water absorption index 4.10 g/g, water solubility index 39.90 %, rehydration ratio 544 % and moisture retention 11.90 % with 75 % desirability.

Keywords: black gram, corn flour, extrusion, physical characteristics

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Authors: A. Alshebani, Y. Swesi, S. Mrayed, F. Altaher

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This paper present some preliminary work on the preparation and physicochemical caracterization of nanocomposite MFI-alumina structures based on alumina hollow fibres. The fibers are manufactured by a wet spinning process. α-alumina particles were dispersed in a solution of polysulfone in NMP. The resulting slurry is pressed through the annular gap of a spinneret into a precipitation bath. The resulting green fibres are sintered. The mechanical strength of the alumina hollow fibres is determined by a three-point-bending test while the pore size is characterized by bubble-point testing. The bending strength is in the range of 110 MPa while the average pore size is 450 nm for an internal diameter of 1 mm and external diameter of 1.7 mm. To characterize the MFI membranes various techniques were used for physicochemical characterization of MFI–ceramic hollow fibres membranes: The nitrogen adsorption, X-ray diffractometry, scanning electron microscopy combined with X emission microanalysis. Scanning Electron Microscopy (SEM) and Energy Dispersive Microanalysis by the X-ray were used to observe the morphology of the hollow fibre membranes (thickness, infiltration into the carrier, defects, homogeneity). No surface film, has been obtained, as observed by SEM and EDX analysis and confirmed by high temperature variation of N2 and CO2 gas permeances before cation exchange. Local analysis and characterise (SEM and EDX) and overall (by ICP elemental analysis) were conducted on two samples exchanged to determine the quantity and distribution of the cation of cesium on the cross section fibre of the zeolite between the cavities.

Keywords: physicochemical characterization of MFI, ceramic hollow fibre, CO2, ion-exchange

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Authors: William Middleton, Nodumo Zulu, Sue Harrison

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Open raceway ponds are currently the most used system for the commercial cultivation of algal biomass, as it is a cost-effective means of production. However, raceway ponds suffer from lower algal productivity when compared to closed photobioreactors. This is due to poor gas exchange between the fluid and the atmosphere. Carbon dioxide (CO₂) mass transfer is a large concern in the production of algae in raceway pond systems. The utilization of atmospheric CO₂ does not support maximal growth; however, CO₂ supplementation in the form of flue gas or concentrated CO₂ is not cost-effective. The introduction of slopes into the raceway system presents a possible improvement to the mass transfer from the air, as seen in previous work conducted at CeBER. Slopes improve turbulence (decreasing the concentration gradient of dissolved CO₂) and can cause air entrainment (allowing for greater surface area and contact time between the air and water). This project tests the findings of previous studies conducted in an indoor lab-scale raceway on a larger scale under outdoor conditions. The addition of slopes resulted in slightly increased CO₂ mass transfer as well as algal growth rate and productivity. However, there were reductions in energy consumption and average fluid velocity in the system. These results indicate a potential to improve the economic feasibility of algal biomass production, but further economic assessment would need to be carried out.

Keywords: algae, raceway ponds, mass transfer, algal culture, biotechnology, reactor design

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Authors: Mehdi Benlarbi, Dalila Oulhaci

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Several physical, human and economic factors come into play in the choice of an irrigation system for developing arid and semi-arid regions. Since it is impossible to define or weight quantitatively all the relevant factors in each case, the choice of the system is often based on subjective preferences rather than explicit analysis. Over the past decade, irrational irrigation in the Ouargla region has evolved to a certain extent based largely on water wastage and which may pose risks to the environment both off-site and at the site. In the whole region, the environment is damaged by excess water because the water tables that tend to be high form swamps that pollute nature on the surface. The purpose of our work is a comparison between sprinkler irrigation and drip irrigation using bottles. By irrigating with the aid of the bottle and giving a volume of 4 liters with a flow rate of one (1) liter per hour, the watering dose received varies between 6 and 7 mm without infiltration losses. And for the case of sprinkler irrigation, the dose received may not exceed 2.5mm. E in some cases, we have a quantity of water lost by infiltration. This shows that irrigation using the bottle is much more efficient than sprinkling. Because, on the one hand, a large amount of water is absorbed by the plant and on the other hand, there is no loss by infiltration. The results obtained are very significant because, on the one hand, we reuse local products, and on the other hand, as the bottles are buried, we avoid water losses by evaporation, especially in dry periods and salinization.

Keywords: resources, water, arid, evaporation, infiltration

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Authors: Yuchen Chen, Dehong Li, Bin Li, Denis Rodrigue, Xiaodong (Alice) Wang

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When selecting insulation materials, not only should their thermal efficiency be considered, but also their impact on the environment. Compared to conventional insulation materials, bio-based materials not only have comparable thermal performance, but they also have a lower embodied energy. Sheep wool has the advantages of low negative health impact, high fire resistance, eco-friendliness, and high moisture resistance. However, studies on applying sheep wool insulation in cold and humid climates are still insufficient. The purpose of this study is to simulate the hygrothermal performance of sheep wool insulation for the Quebec City climate, as well as analyze the mold growth risks. The results show that a sheep wool wall has better thermal performance than a reference wall and that both meet the minimum requirements of the Quebec Code for the thermal performance of above-ground walls. The total water content indicates that the sheep wool wall can reach dynamic equilibrium in the Quebec climate and can dry out. At the same time, a delay of almost four months in the maximum total water content indicates that the sheep wool wall has high moisture absorption compared to the reference wall. The hygrothermal profiles show that the sheathing-insulation interface of both walls is at the highest risk for condensation. When the interior surface gypsum was replaced by stucco, the mold index significantly dropped.

Keywords: sheep wool, water content, hygrothermal performance, mould growth risk

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Authors: N. K. Chougule, G. V. Parishwad

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The pin fin heat sink is a novel heat transfer device to transfer large amount of heat through with very small temperature differences and it also possesses large uniform cooling characteristics. Pin fins are widely used as elements that provide increased cooling for electronic devices. Increasing demands regarding the performance of such devices can be observed due to the increasing heat production density of electronic components. For this reason, extensive work is being carried out to select and optimize pin fin elements for increased heat transfer. In this paper, the effects of design parameters and the optimum design parameters for a Pin-Fin heat sink (PFHS) under multi-jet impingement case with thermal performance characteristics have been investigated by using Taguchi methodology based on the L9 orthogonal arrays. Various design parameters, such as pin-fin array size, gap between nozzle exit to impingement target surface (Z/d) and air velocity are explored by numerical experiment. The average convective heat transfer coefficient is considered as the thermal performance characteristics. The analysis of variance (ANOVA) is applied to find the effect of each design parameter on the thermal performance characteristics. Then the results of confirmation test with the optimal level constitution of design parameters have obviously shown that this logic approach can effective in optimizing the PFHS with the thermal performance characteristics. The analysis of the Taguchi method reveals that, all the parameters mentioned above have equal contributions in the performance of heat sink efficiency. Experimental results are provided to validate the suitability of the proposed approach.

Keywords: Pin Fin Heat Sink (PFHS), Taguchi method, CFD, thermal performance

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Authors: Yongseok Hong, Kurt Louis Solis

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In the present study, a hybrid sorbent using the metal organic framework (MOF), UiO-66, and powdered activated carbon (pAC) is synthesized to remove cationic and anionic metals simultaneously. UiO-66 is an octahedron-shaped MOF with a Zr₆O₄(OH)₄ metal node and 1,4-benzene dicarboxylic acid (BDC) organic linker. Zr-based MOFs are attractive for trace element remediation in wastewaters, because Zr is relatively non-toxic as compared to other classes of MOF and, therefore, it will not cause secondary pollution. Most remediation studies with UiO-66 target anions such as fluoride, but trace element oxyanions such as arsenic, selenium, and antimony have also been investigated. There have also been studies involving mercury removal by UiO-66 derivatives, however these require post-synthetic modifications or have lower effective surface areas. Activated carbon is known for being a readily available, well-studied, effective adsorbent for metal contaminants. Solvothermal method was employed to prepare hybrid sorbent from UiO66 and activated carbon, which could be used to remove mercury and selenium simultaneously. The hybrid sorbent was characterized using FSEM-EDS, FT-IR, XRD, and TGA. The results showed that UiO66 and activated carbon are successfully composited. From BET studies, the hybrid sorbent has a SBET of 1051 m² g⁻¹. Adsorption studies were performed, where the hybrid showed maximum adsorption of 204.63 mg g⁻¹ and 168 mg g⁻¹ for Hg (II) and selenite, respectively, and follows the Langmuir model for both species. Kinetics studies have revealed that the Hg uptake of the hybrid is pseudo-2nd order and has rate constant of 5.6E-05 g mg⁻¹ min⁻¹ and the selenite uptake follows the simplified Elovich model with α = 2.99 mg g⁻¹ min⁻¹, β = 0.032 g mg⁻¹.

Keywords: adsorption, flue gas wastewater, mercury, selenite, metal organic framework

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Authors: Jenny Radeva, Anke-Gundula Roth, Christian Goebbert, Robert Niestroj-Pahl, Lars Daehne, Axel Wolfram, Juergen WIese

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The presented investigation studies the correlation between the process parameters of Layer-by-Layer (LbL) coatings and properties of the produced hybrid membranes for water treatment. The coating of alumina ceramic support membrane with polyelectrolyte multilayers on top results in hybrid membranes with increased fouling resistant behavior, high retention (up to 90%) of salt ions and various pharmaceuticals, selectivity to various organic molecules as known from LbL coated polyether sulfone membranes and the possibility of pH response control. Chosen polyelectrolytes were added to the support using the LbL-coating process. Parameters like the type of polyelectrolyte, ionic strength, and pH were varied in order to find the most suitable process conditions and to study how they influence the properties of the final product. The applied LbL-films was investigated in respect to its homogeneity and penetration depth. The analysis of the layer buildup was performed using fluorescence labeled polyelectrolyte molecules and Confocal Laser Scanning Microscopy as well as Scanning and Transmission Electron Microscopy. Furthermore, the influence of the coating parameters on the porosity, surface potential, retention, and permeability of the developed hybrid membranes were estimated. In conclusion, a comparison was drawn between the filtration performance of the uncoated alumina ceramic membrane and modified hybrid membranes.

Keywords: water treatment, membranes, ceramic membranes, hybrid membranes, layer-by-layer modification

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Authors: Jitka Hroudová, Martin Sedlmajer, Jiří Zach

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Problems insulation of building structures is often closely connected with the problem of moisture remediation. In the case of historic buildings or if only part of the redevelopment of envelope of structures, it is not possible to apply the classical external thermal insulation composite systems. This application is mostly effective thermal insulation plasters with high porosity and controlled capillary properties which assures improvement of thermal properties construction, its diffusion openness towards the external environment and suitable treatment capillary properties of preventing the penetration of liquid moisture and salts thereof toward the outer surface of the structure. With respect to the current trend of reducing the energy consumption of building structures and reduce the production of CO2 is necessary to develop capillary-active materials characterized by their low density, low thermal conductivity while maintaining good mechanical properties. The aim of researchers at the Faculty of Civil Engineering, Brno University of Technology is the development and study of hygrothermal behaviour of optimal materials for thermal insulation and rehabilitation of building structures with the possible use of alternative, less energy demanding binders in comparison with conventional, frequently used binder, which represents cement. The paper describes the evaluation of research activities aimed at the development of thermal insulation and repair materials using lightweight aggregate and alternative binders such as metakaolin and finely ground fly ash.

Keywords: thermal insulating plasters, rehabilitation materials, thermal conductivity, lightweight aggregate, alternative binders.

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Authors: Hayder H. Kareem

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Groundwater recharge is a crucial parameter for any groundwater management system. The variability of the recharge rates and the difficulty in estimating this factor in many processes by direct observation leads to the complexity of estimating the recharge value. Various methods are existing to estimate the groundwater recharge, with some limitations for each method to be able for application. This paper focuses particularly on a real study area, Al-Najaf City, Iraq. In this city, there are few groundwater aquifers, but the aquifer which is considered in this study is the closest one to the ground surface, the Dibdibba aquifer. According to the Aridity Index, which is estimated in the paper, Al-Najaf City is classified as a region located in an arid climate, and this identified that the most appropriate method to estimate the groundwater recharge is Thornthwaite's formula or Thornthwaite's method. From the calculations, the estimated average groundwater recharge over the period 1980-2014 for Al-Najaf City is 40.32 mm/year. Groundwater recharge is completely affected the groundwater table level (groundwater head). Therefore, to make sure that this value of recharge is true, the MODFLOW program has been used to apply this value through finding the relationship between the calculated and observed heads where a groundwater model for the Al-Najaf City study area has been built by MODFLOW to simulate this area for different purposes, one of these purposes is to simulate the groundwater recharge. MODFLOW results show that this value of groundwater recharge is extremely high and needs to be reduced. Therefore, a further sensitivity test has been carried out for the Al-Najaf City study area by the MODFLOW program through changing the recharge value and found that the best estimation of groundwater recharge value for this city is 16.5 mm/year where this value gives the best fitting between the calculated and observed heads with minimum values of RMSE % (13.175) and RSS m² (1454).

Keywords: Al-Najaf City, groundwater modelling, recharge estimation, visual MODFLOW

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Authors: Dana J. Abed, Mu'tasim S. Abdel-Jaber, Nasim K. Shatarat

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In this paper, an experimental study on twelve square columns was conducted to investigate the influence of cross-sectional size on axial compressive capacity of carbon fiber reinforced polymers (CFRP) wrapped square reinforced concrete (RC) short columns subjected to eccentric loadings. The columns were divided into three groups with three cross sections (200×200×1200, 250×250×1500 and 300×300×1800 mm). Each group was tested under two different eccentricities: 10% and 20% of the width of samples measured from the center of the column cross section. Four columns were developed in each arrangement. Two columns in each category were left unwrapped as control samples, and two were wrapped with one layer CFRP perpendicular to the specimen surface. In general; CFRP sheets has enhanced the performance of the strengthened columns compared to the control columns. It was noticed that the percentage of compressive capacity enhancement was decreased by increasing the cross-sectional size, and increasing loading eccentricity generally leads to reduced load bearing capacity in columns. In the same group specimens, when the eccentricity increased the percentage of enhancement in load carrying capacity was increased. The study concludes that the optimum use of the CFRP sheets for axial strength enhancement is for smaller cross-section columns under higher eccentricities.

Keywords: CFRP, columns, eccentric loading, cross-sectional

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Authors: Javiera Poblete, Fernando Gajardo, Katherina Fernandez

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Graphene, and its derivatives such as graphene oxide (GO), are emerging nanoscopic materials, with interesting physical and chemical properties. From them, it is possible to develop three-dimensional macrostructures, such as aerogels, which are characterized by a low density, high porosity, and large surface area, having a promising structure for the development of materials. The use of GO as a precursor of these structures provides a wide variety of materials, which can be developed as a result of the functionalization of their oxygenated groups, with specific compounds such as polyethylene glycol (PEG). The synthesis of aerogels of GO-PEG for non-covalent interactions has not yet been widely reported, being of interest due to its feasible escalation and economic viability. Thus, this work aims to develop a non-covalently functionalized GO-PEG aerogels and characterize them physicochemically. In order to get this, the GO was synthesized from the modified hummers method and it was functionalized with the PEG by polymer-assisted GO gelation (crosslinker). The gelation was obtained for GO solutions (10 mg/mL) with the incorporation of PEG in different proportions by weight. The hydrogel resulting from the reaction was subsequently lyophilized, to obtain the respective aerogel. The material obtained was chemically characterized by analysis of Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and X-ray diffraction (XRD), and its morphology by scanning electron microscopy (SEM) images; as well as water absorption tests. The results obtained showed the formation of a non-covalent aerogel (FTIR), whose structure was highly porous (SEM) and with a water absorption values greater than 50% g/g. Thus, a methodology of synthesis for GO-PEG was developed and validated.

Keywords: aerogel, graphene oxide, polyethylene glycol, synthesis

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Authors: Mohamed Alsafy, Samir El-Gendy, Ashraf Karkoura, Doha Shokry

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The purpose of the current study was to investigate the development of the chicken ovary. One hundred fertilized egg of Alexandria breed of chicken used. The whole embryo has undergone the light microscopic examination at HH20 (E.3), HH21 (E.3.5), HH23 (E.4), HH29 (E.6) and HH34 (E.8). The ovary has undergone the light microscopic examination at HH38 (E.12) and HH42 (E.16), SEM at HH26 (E.5), HH29 (E.6), HH36 (E.10), HH38 (E.12), HH39 (E.13) and HH42 (E.16), TEM at HH38 (E.12) and HH42 (E.16). The genital ridge appeared by a thickening of the coelomic epithelium medioventral surface of the developing mesonephroi at HH20 (E.3). The boundaries of the undifferentiating gonads defined clearly separated from the mesonephroi. The undifferentiated gonads bulged as a distinct organ in the coelomic cavity at HH23 (E.4). At the initial stages of the gonadogenesis, the germinal epithelium was stratified squamous epithelium. The PGCs appeared at the genital ridge at HH21 (E.3.5). The PGCs observed at the dorsal mesentery with few microvilli and showed positive PAS reaction due to the glycogen content in their cytoplasm. The left-right gonadal asymmetry firstly detected by the number of PGCs migrating toward the left gonadal ridge more than the right at HH20 (E.3) and the macroscopic examination of gonadal asymmetry began at HH34 (E.8). The left ovary appeared a smooth rod-shape, its stroma showed lipid droplets, and its parenchyma showed an extensive arrangement of interstitial cords at HH42 (E.16).

Keywords: ovary, Alexandria chicken, light microscopy, SEM, TEM

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Authors: N. Matveev, A. Pervov

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Local utilities often face problems of local industrial wastes, storm water disposal due to existing strict regulations. For many local industries, the problem of wastewater treatment and discharge into surface reservoirs can’t be solved through the use of conventional biological treatment techniques. Current discharge standards require very strict removal of a number of impurities such as ammonia, nitrates, phosphate, etc. To reach this level of removal, expensive reagents and sorbents are used. The modern concept of rational water resources management requires the development of new efficient techniques that provide wastewater treatment and reuse. As RO membranes simultaneously reject all dissolved impurities such as BOD, TDS, ammonia, phosphates etc., they become very attractive for the direct treatment of wastewater without biological stage. To treat wastewater, specially designed membrane "open channel" modules are used that do not possess "dead areas" that cause fouling or require pretreatment. A solution to RO concentrate disposal problem is presented that consists of reducing of initial wastewater volume by 100 times. Concentrate is withdrawn from membrane unit as sludge moisture. The efficient use of membrane RO techniques is connected with a salt balance in water system. Thus, to provide high ecological efficiency of developed techniques, all components of water supply and wastewater discharge systems should be accounted for.

Keywords: reverse osmosis, stormwater treatment, open-channel module, wastewater reuse

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Authors: R. Harman Dwi, Ryan Avirsa, P. Abraham Ivan

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Understanding of temperatures in the past, present, and future temperatures can be possible to do by analysis abundance of fossil foraminifera. This research was conducted in Sambipitu Formation, Ngalang River, Nglipar, Gunung Kidul Regency. The research method is divided into 3 stages: 1) study of literature, research based on previous researchers, 2) spatial, observation and sampling every 5-10 meters, 3) descriptive, analyzing samples consisting of a 10-gram sample weight, washing sample using 30% peroxide, biostratigraphy analysis, paleotemperature analysis using abundance of fossil, diversity analysis using Simpson diversity index method, and comparing current temperature data. There are two phases based on the appearance of Globorotalia menardii and Pulleniatina obliqueculata pointed to Phase Tropical Area, and the appearance of fossil Globigerinoides ruber and Orbulina universa fossil shows the phase of Subtropical Area. Paleotemperatur based on the appearance of Globorotalia menardii, Globigerinoides trilobus, Globigerinoides ruber, Orbulina universa, and Pulleniatina obliqueculata pointed to Warm Water Area and Warm Water Area (average surface water approximate 25°C).

Keywords: abundance, biostratigraphy, Simpson diversity index method, paleotemperature

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Authors: Parnaz Boodagh, Danila Vella, Antonio Damore, Laura Modica De Mohac, Sang-Ho Ye, Garret Coyan, Gaetano Burriesci, William Wagner, Federica Cosentino

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The use of cardiac patches is among the main therapeutic solution for cardiovascular diseases, a leading mortality cause in the world with an increasing trend, responsible of 19 millions deaths in 2020. Several classes of biomaterials serve that purpose, both of synthetic origin and biological derivation, and many bioengineered treatment alternatives were proposed to satisfy two main requirements, providing structural support and promoting tissue remodeling. The objective of this paper is to compare the mechanical properties and the characterization of four cardiac patches: the Adeka, PhotoFix, CorPatch, and CardioCel patches. In vitro and in vivo tests included: biaxial, uniaxial, ball burst, suture retention for mechanical characterization; 2D surface topography, 3D volume and microstructure, and histology assessments for structure characterization; in vitro test to evaluate platelet deposition, calcium deposition, and macrophage polarization; rat right ventricular outflow tract (RVOT) models at 8- and 16-week time points to characterize the patch-host interaction. Lastly, the four patches were used to produce four stented aortic valve prosthesis, subjected to hydrodynamic assessment as well as durability testing to verify compliance with the standard ISO.

Keywords: cardiac patch, cardiovascular disease, cardiac repair, blood contact biomaterial

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Authors: Maisarah Jaafar, Neil I. Ward

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Volcanic and geothermal activity can result in the release of arsenic (As), manganese (Mn), iron, selenium (Se), molybdenum (Mo) and uranium (U) into natural waters. Several studies have reported high levels of these elements in surface and groundwater in Argentina. The main focus has been on As associated with volcanic ash deposits. This study reports the trace element levels of groundwater from an agricultural region of south-eastern La Pampa and southern Buenos Aires provinces, Argentina which have reported high levels of human health problems (bone/teeth disorders, depression, arthritis, etc). Fifty-eight groundwater samples were collected from wells adjacent to Ruta 35 and an Agilent 7700x inductively coupled plasma mass spectrometer (ICP-MS) were used for total elemental analysis. Physicochemical analysis confirmed pH range of 7.05-8.84 and variable conductivity (988-3880 µS/cm) with total dissolved solid content of 502-1989 mg/l. The majority water samples are in an oxidizing environment (Eh= 45-146 mV). Total As levels ranged from (µg/l): 13.08 – 319.4 for La Pampa (LP) and 39.6 – 189.4 for Buenos Aires (BA); all above the WHO Guideline for Drinking Water, 10 µg/l As. Interestingly, Mo (LP: 1.85 – 85.39 µg/l; BA: 4.61– 55.55 µg/l;), Se (LP: 1.2 – 16.59 µg/l; BA: 0.3– 6.94 µg/l;) and U (LP: 1.85 – 85.39 µg/l; BA: 4.61– 55.55 µg/l;) levels are lower than reported values for northern La Pampa. Inter-elemental correlation displayed positive statistically significant between As-Mo, A-Se, As-U while negative statistically significant between As-Mn and As-Fe. This confirms that the source of the trace element is similar to that reported for other region of Argentina, namely volcanic ash deposition.

Keywords: Argentina, groundwater, trace element, volcanic activity

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Authors: Claudia Vergara, Oscar Valdes, Jaime Tapia, Leonardo Santos

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The poly(amidoamine) dendrimers (PAMAM) are a class of material introduced by D. Tomalia. Modifications of the PAMAM dendrimer with several functional groups have attracted the attention for new interesting properties and new applications in many fields such as chemistry, physics, biology, and medicine. However, in the last few years, the use of dendrimers in environmental applications has increased due to pollution concerns. In this contribution, we report the synthesis of three new PAMAM derivates modified with asparagine aminoacid supported in cellulose: PG0-Asn (PAMAM-asparagine), PG0-Asn-Trt (with trityl group) and PG0-Asn-Boc-Trt (with tert-butyl oxycarbonyl group). The functionalization of generation 0 PAMAM dendrimer was carried out by amidation reaction by using an EDC/HOBt protocol. In a second step, functionalized dendrimer was covalently supported to the cellulose surface and used to study the capture of uranyl ions from aqueous solution by fluorescence spectroscopy. The structure and purity of the desired products were confirmed by conventional techniques such as FT-IR, MALDI, elemental analysis, and ESI-MS. Batch experiments were carried out to determine the affinity of uranyl ions with the dendrimer in aqueous solution. Firstly, the optimal conditions for uranyl capture were obtained, where the optimum pH for the removal was 6, the contact time was 4 hours, the initial concentration of uranyl was 100 ppm, and the amount of the adsorbent to be used was 2.5 mg. PAMAM significantly increased the capture of uranyl ions with respect to cellulose as the starting substrate, reaching 94.8% of capture (PG0), followed by 91.2% corresponding to PG0-Asn-Trt, then 70.3% PG0-Asn and 24.2% PG0-Asn-Boc-Trt. These results show that the PAMAM dendrimer is a good option to remove uranyl ions from aqueous solutions.

Keywords: asparagine, cellulose, PAMAM dendrimer, uranyl ions

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Authors: S. Lakel, F. Elhamra, M. Ibrir, K. Almi

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There is a growing interest in Zn1-xBexO (ZBO)/ZnO hetero structures and quantum wells since the band gap energy of Zn1-xBexO solid solutions can be turned over a very large range (3.37–10.6 eV) as a function of the Be composition. ZBO/ZnO has been utilized in ultraviolet light emission diodes and lasers, and may find applications as active elements of various other electronic and optoelectronic devices. Band gap engineering by Be substitution enables the facile preparation of barrier layers and quantum wells in device structures. In addition, ZnO and its ternary alloys, as piezoelectric semiconductors, have been used for high-frequency surface acoustic wave devices in wireless communication systems due to their high acoustic velocities and large electromechanical coupling. However, many important parameters such as elastic constants, bulk modulus, Young’s modulus and band-gap bowing. First-principles calculations of the structural, electrical and elastic properties of Zn1-xBexO as a function of the Be concentration x have been performed within density functional theory using norm-conserving pseudopotentials and local density approximation (LDA) for the exchange and correlation energy. The alloys’ lattice constants may deviate from the Vegard law. As Be concentration increases, the elastic constants, the bulk modulus and Young’s modulus of the alloys increase, the band gap increases with increasing Be concentration and Zn1-xBexO alloys have direct band. Our calculated results are in good agreement with experimental data and other theoretical calculations.

Keywords: DFT calculation, norm-conserving pseudopotentials, ZnBeO alloys, ZnO

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Authors: Kanayo Kenneth Asogwa

Abstract:

The influence of the flow of nanoparticles in nanofluids across a vertical surface is significant, and its application in medical sciences, engineering, pharmaceutical, and food industries is enormous & widely published. However, the comparative examination of alumina nanoparticles with cupric nanoparticles past a rapid progressive Riga plate remains unknown. Thus, this report investigates water-based alumina and cupric nanoparticles passing through an exponentially accelerated Riga plate. Nanofluids containing copper (II) oxide (CuO) and aluminum oxide (Al2O3) nanoparticles are considered. The Laplace transform technique is used to solve the partial differential equations guiding the flow. The effect of various factors on skin friction coefficient, Nusselt number, velocity and temperature profiles is investigated and reported in tabular and graphical form. The upsurge of Modified Hartmann number and radiative impact improves copper (II) oxide nanofluid compared to aluminum oxide nanofluid due to Lorentz force and since CuO is a better heat conductor. At the same time, heat absorption and reactive species favor a slight decline in Alumina nanofluid than Cupric nanofluid in the thermal and velocity fields. The higher density of Cupric nanofluid is enhanced by increasing nanoparticle volume fraction over Alumina nanofluid with a decline in velocity distribution.

Keywords: alumina, cupric, nanoparticles, water-based

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Authors: Min Wu, Shuming Shen, Xuhong Yang, Rencheng Tang

Abstract:

Every year, numerous organic wastes from fiber byproducts of the wool textile industry, poor quality raw wools not fit for spinning, horns, nails and feathers from butchery are disposed. These wastes are abundant in keratin which is a renewable material. Wool fiber/keratin/PVA composites with different proportions were prepared in this study, and the influence of the proportions on their structure and properties were studied, aiming to understand the potential application of keratin in the field of biomedicine, degradable wrapper, and cosmetics film, and provide a new way to reuse keratin wastes. The urea / sodium sulfide / sodium dodecyl sulfate (SDS) method was used to dissolve the wool. After filtration and dialysis, the wool keratin solution was achieved. Then the keratin solution and polyvinal (PVA) solution were blended in different proportions, and the wool fibers cut into a certain length were cast into the blended solution. Thereby, various wool fiber/keratin/PVA composite films with different proportions were formed through pouring the solution into a flat box and drying at room temperature. The surface morphology, molecular structure, and mechanical property of the composite films were studied. The results showed that, there are α-helix structure, β-sheet and random coil conformations in the pure keratin film, as well as in the wool fiber. Compared with wool fiber, the crystallinity of keratin decreased. PVA can obviously improve the mechanical property of the blended film. When the blended ratio of keratin and PVA is 20:80, the mechanical property of the blended film is greatly improved. The composite films with 8%-16% of wool fibers have better flexibility than those without wool fibers.

Keywords: composite film, keratin, mechanical property, morphological structure, PVA, wool fiber

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Authors: Ahmed I. Al-Amoud

Abstract:

A laboratory and field study were conducted on subsurface drip irrigation systems. In the first laboratory study, eight subsurface drip irrigation lines available locally, were selected and a number of experiments were made to evaluate line hydraulic characteristics to insure it's suitability for drip irrigation design requirements and high performance to select the best for field experiments. The second study involves field trials on mature date palm trees to study the effect of subsurface drip irrigation system on the yield and water consumption of date palms, and to compare that with the traditional surface drip irrigation system. Experiments were conducted in Alwatania Agricultural Project, on 50 mature palm trees (17 years old) of Helwa type with 10 meters spacing between rows and between trees. A high efficiency subsurface line (Techline) was used based on the results of the first study. Irrigation scheduling was made through a soil moisture sensing device to ensure enough soil water levels in the soil. Experiment layouts were installed during 2001 season, measurements continued till end of 2008 season. Results have indicated that there is an increase in the yield and a considerable saving in water compared to the conventional drip irrigation method. In addition there were high increases in water use efficiency using the subsurface system. The subsurface system proves to be durable and highly efficient for irrigating date palm trees.

Keywords: drip irrigation, subsurface drip irrigation, date palm trees, date palm water use, date palm yield

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Authors: Yih-Chien Chen, Yue-Xuan Du, Min-Zhe Weng

Abstract:

Carbon monoxide is a substance produced by the incomplete combustion. It is toxic even at concentrations of less than 100ppm. Since it is colorless and odorless, it is difficult to detect. CO sensors have been developed using a variety of physical mechanisms, including semiconductor oxides, solid electrolytes, and organic semiconductors. Many works have focused on using semiconducting sensors composed of sensitive layers such as ZnO, TiO₂, and NiO with high sensitivity for gases. However, these sensors working at high temperatures increased their power consumption. On the other hand, the dielectric resonator (DR) is attractive for gas detection due to its large surface area and sensitivity for external environments. Materials that are to be employed in sensing devices must have a high-quality factor. Numerous researches into the fergusonite-type structure and related ceramic systems have explored. Extensive research into RENbO₄ ceramics has explored their potential application in resonators, filters, and antennas in modern communication systems, which are operated at microwave frequencies. Nd(Ti₀.₅W₀.₅)O₄ ceramics were synthesized herein using the conventional mixed-oxide method. The Nd(Ti₀.₅W₀.₅)O₄ ceramics were prepared using the conventional solid-state method. Dielectric constants (εᵣ) of 15.4-19.4 and quality factor (Q×f) of 3,600-11,100 GHz were obtained at sintering temperatures in the range 1425-1525°C for 4 h. The dielectric properties of the Nd(Ti₀.₅W₀.₅)O₄ ceramics at microwave frequencies were found to vary with the sintering temperature. For a further understanding of these microwave dielectric properties, they were analyzed by densification, X-ray diffraction (XRD), and by making microstructural observations.

Keywords: dielectric constant, dielectric resonators, sensors, quality factor

Procedia PDF Downloads 260

Authors: Sonia Hamiche, Naima Bouzidi, Mohamed Reda Zahi, Yasmina Daghbouche, Abdelmalek Badis, Mohamed El Hattab

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This study was carried out on the brown alga Zonaria tourfortii harvested on the central coast of Algeria. The chemical study enabled the characterization of phenolic compounds, mainly acyl phloroglucinol and chromone metabolites. The study isolated a significant quantity of all-cis-5,8,11,14,17 eicosapentanoic acid (EPA). Based on a literature review, we have proposed a biosynthetic pathway leading from EPA to phenolic metabolites. Bacterial screening from the algal surface led to isolate 30 bacterial strains, including 26 Gram+ containing the Staphylococcus and Bacillus genus, and 4 Gram- containing the Acinetobacter and Enterobacteracea genus. In terms of activity profiles, strain S13 (identified as Bacillus amyloliquefaciens based on 16S rRNA technique) proved highly interesting inhibitory activities against target germs, as well as its production of diffusible and volatile compounds. Bacterial cells from the B. amyloliquefaciens S13 strain were used to recover a volatile fraction. Analysis was carried out by gas chromatography-mass spectrometry. The main volatile compounds identified were: 13-epi-manoyl oxide (29.39%), manool (17.39%), 15,16-dinorlabd-8(20)-en-13-one (13.17%), labda-8(17),13Z-dien-15-ol (9. 51%) and 3-acetoxy-13 epimanoyl oxide (5.26%) belonging to the labdane class of diterpenes, the latter having never been described in the category of microbial volatile organic compounds. Ecological aspects were discussed.

Keywords: chemical analysis, acylphloroglucinols, phenolic compounds, microbial volatiles, Zonaria tournefortii

Procedia PDF Downloads 61

Authors: Shilpa Khobragade, Carlos Da Silva Granja, Niklas Sandström, Igor Efimov, Victor P. Ostanin, Wouter van der Wijngaart, David Klenerman, Sourav K. Ghosh

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Rapid, label-free and direct detection of pathogenic bacteria is critical for the prevention of disease outbreaks. This paper for the first time attempts to probe the nonlinear acoustic response of quartz crystal resonator (QCR) functionalized with specific DNA aptamers for direct detection and quantification of viable E. coli KCTC 2571 bacteria. DNA aptamers were immobilized through biotin and streptavidin conjugation, onto the gold surface of QCR to capture the target bacteria and the detection was accomplished by shift in amplitude of the peak 3f signal (3 times the drive frequency) upon binding, when driven near fundamental resonance frequency. The developed nonlinear acoustic aptasensor system demonstrated better reliability than conventional resonance frequency shift and energy dissipation monitoring that were recorded simultaneously. This sensing system could directly detect 10⁽⁵⁾ cells/mL target bacteria within 30 min or less and had high specificity towards E. coli KCTC 2571 bacteria as compared to the same concentration of S.typhi bacteria. Aptasensor response was observed for the bacterial suspensions ranging from 10⁽⁵⁾-10⁽⁸⁾ cells/mL. Conclusively, this nonlinear acoustic aptasensor is simple to use, gives real-time output, cost-effective and has the potential for rapid, specific, label-free direction detection of bacteria.

Keywords: acoustic, aptasensor, detection, nonlinear

Procedia PDF Downloads 567

Authors: Arghavan Kazemi, Hossein Radipour

Abstract:

Microsilica (silica foam) is a byproduct of ferrosilicon production and silicon metal. Microsilica particles have a spherical shape, an average diameter of 0.15 µm, and a specific surface area of 15-25 m². g-¹. The overall density of this material is 150-700 kg.m-³. Many researchers have investigated the effect of adding microsilica on the flow properties of cement mixtures. This paper investigated the effect of adding microsilica on the flow behavior and injectability of silica-based paste. For this purpose, different percentages of microsilica have been used to prepare the paste. The rheometric test was performed on all the samples with different percentages of microsilica additives using an MCR300 rotary viscometer at a temperature of 70°C. In addition, the ability to inject pastes containing different amounts of microsilica at pressures of 25, 40, 50, and (bar) 60 at constant temperature and flow in a mold with dimensions of 80 × 80 × 0.5 mm³ has been investigated. Then, the effect of microsilica addition on the strength, porosity percentage, and leachability of the sintered core was studied. The results show that the rheological behavior of the paste is pseudoplastic; also, the silane index decreases with the increase in the percentage of microsilica addition, and the viscosity increases. On the other hand, the addition of microsilica has led to the appearance of thixotropic in the paste. By increasing the amount of microsilica, the injectability has significantly improved at low pressures. The strength of the sintered core increases with the increase of microsilica and the amount of remaining porosity and leachability decreases.

Keywords: microsilica, rheological behavior, injectability, injection molding, silica-based ceramic cores, leachability

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Authors: Hatim Laalej, Salvador Sumohano-Verdeja, Thomas McLeay

Abstract:

Monitoring of tool wear in milling operations is essential for achieving the desired dimensional accuracy and surface finish of a machined workpiece. Although there are numerous statistical models and artificial intelligence techniques available for monitoring the wear of cutting tools, these techniques cannot pin point which cutting edge of the tool, or which insert in the case of indexable tooling, is worn or broken. Currently, the task of monitoring the wear on the tool cutting edges is carried out by the operator who performs a manual inspection, causing undesirable stoppages of machine tools and consequently resulting in costs incurred from lost productivity. The present study is concerned with the development of a flute tracking system to segment signals related to each physical flute of a cutter with three flutes used in an end milling operation. The purpose of the system is to monitor the cutting condition for individual flutes separately in order to determine their progressive wear rates and to predict imminent tool failure. The results of this study clearly show that signals associated with each flute can be effectively segmented using the proposed flute tracking system. Furthermore, the results illustrate that by segmenting the sensor signal by flutes it is possible to investigate the wear in each physical cutting edge of the cutting tool. These findings are significant in that they facilitate the online condition monitoring of a cutting tool for each specific flute without the need for operators/engineers to perform manual inspections of the tool.

Keywords: machining, milling operation, tool condition monitoring, tool wear prediction

Procedia PDF Downloads 303