Search results for: contact surface

Authors: Narin Salehiyan

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Early stage morphogenesis requires the execution of complex systems that direct the nearby conduct of gatherings of cells. The organization of such instruments has been, for the most part, deciphered through the recognizable proof of moderated groups of flagging pathways that spatially and transiently control cell conduct. In any case, how this data is handled to control cell shape and cell elements is an open territory of examination. The structure that rises up out of differing controls, for example, cell science, material science and formative science, focuses to bond and cortical actin arranges as controllers of cell surface mechanics. In this specific circumstance, a scope of formative marvels can be clarified by the guideline of cell surface pressure.

Keywords: cell, tissue damage, morphogenesis, cell conduct

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Authors: Rebecca Heron, Julie Karsten, Lena Schweikert

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Adverse consequences of stigma towards pedophilia can, among other things, increase dynamic risk factors for sexual offending. Decreasing stigma, therefore, is a plausible approach in the attempt to prevent child sexual abuse. Stigma research suggests that providing direct contact to a stigmatized individual is the most efficient way of reducing stigma. The present study involved an educational intervention, followed by direct contact to a pedophile, to maximize effectiveness. It aimed at finding out whether a dichotomous anti-stigma intervention can change psychology students' attitudes towards pedophiles regarding perceived dangerousness, intentionality, deviance, and punitive attitudes. In a one sample pre-post design, 162 students of the University of Groningen attended a lecture about pedophilia, which was held by a psychology master’s student. Participants learned about child sex offending and pedophilia in addition to the importance of distinguishing between pedophiles and child sex offenders (CSOs). The guest lecturer Gabriel, shared his experiences about growing up, coping, and living with pedophilia. Results of the Wilcoxon signed-rank test revealed significantly diminished negative attitudes towards pedophiles after the intervention. Students perceived pedophiles as less dangerous, having less intent, and being less psychologically deviant. Additionally, students' punitive attitudes towards pedophiles diminished significantly. Also, a thematic analysis revealed that students were highly interested in the topic of pedophilia and greatly appreciative of Gabriel sharing his story. This study was the first to provide direct contact with a pedophile within an anti-stigma intervention.

Keywords: pedophilia, anti-stigma intervention, punitive attitudes, attitude change

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Authors: Sukant Mehra, Parth Gupta, Varun Arora, Sarvoday Singh, Amit Kohli

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The study was emphasised on dry sliding wear behavior of AISI 1042 steel. Dry sliding wear tests were performed using pin-on-disk apparatus under normal loads of 5, 7.5 and 10 kgf and at speeds 600, 750 and 900 rpm. Response surface methodology (RSM) was utilized for finding optimal values of process parameter and experiment was based on rotatable, central composite design (CCD). It was found that the wear followed linear pattern with the load and rpm. The obtained optimal process parameters have been predicted and verified by confirmation experiments.

Keywords: central composite design (CCD), optimization, response surface methodology (RSM), wear

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Authors: Sirwan Kamal, Hsein Kew, Hamid Jahromi

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This paper reports results of a study conducted to investigate strength, sorptivity, and permeability under pressure of concrete specimens, cured using a water-based curing compound. The specimens are treated with waterproofing admixtures or surface treatments to enhance performance while exposed to water. Four types of concrete specimens were prepared in the laboratory, Portland cement (CEM I), Portland-fly ash (CEM II/A-V), Blast-furnace cement (CEM III) and Portland-silica fume (CEM II/A-D). Concrete cubes were de-molded three hours after casting, and sprayed with a curing compound. Admixtures were added to the mix during batching, whereas surface treatments were applied on concrete after 28 days. Compressive strength test was carried out to assess the efficiency of curing compound to develop required strength. In addition, sorptivity and permeability tests were conducted to evaluate the performance of treated specimens with respect to water ingress. Results show that strength development in specimens cured with curing compound achieved up to 96% and 90% at 7 and 28 days respectively, compared to cubes cured in water. Moreover, specimens treated with waterproofing admixtures or surface treatments materials characterized by hydrophobic impregnation considerably reduced water penetration compared to untreated control cubes. On the other hand, cubes treated with admixtures or surface treatments materials characterized by crystalline effect were ineffective in reducing water penetration.

Keywords: admixtures, concrete, curing compound, surface treatments

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Authors: Saleh H. Abud, Z. Hassan, F. K. Yam

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Characteristics of MSM photodetector based on a porous In0.08Ga0.92N thin film were reported. Nanoporous structures of n-type In0.08Ga0.92N/AlN/Si thin films were synthesized by photoelectrochemical (PEC) etching at a ratio of 1:4 of HF:C2H5OH solution for 15 min. The structural and optical properties of pre- and post-etched thin films were investigated. Field emission scanning electron microscope and atomic force microscope images showed that the pre-etched thin film has a sufficiently smooth surface over a large region and the roughness increased for porous film. Blue shift has been observed in photoluminescence emission peak at 300 K for porous sample. The photoluminescence intensity of the porous film indicated that the optical properties have been enhanced. A high work function metals (Pt and Ni) were deposited as a metal contact on the porous films. The rise and recovery times of the devices were investigated at 390 nm chopped light. Finally, the sensitivity and quantum efficiency were also studied.

Keywords: porous InGaN, photoluminescence, SMS photodetector, atomic force microscopy

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Authors: Yufei Peng, Zhen Qin, Jianbe Li, Jidong Long

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The thermal cathode is widely used in accelerators, FELs and kinds of vacuum electronics. However, emission nonuniformity exists due to surface profile, material distribution, temperature variation, crystal orientation, etc., which will cause intrinsic emittance growth, brightness decline, envelope size augment, device performance deterioration or even failure. To understand how emittance is manipulated by emission nonuniformity, an intrinsic emittance model consisting of contributions from macro and micro surface nonuniformity is developed analytically based on general thermal emission model at temperature limited regime according to a real 3mm cathode. The model shows relative emittance increased about 50% due to temperature variation, and less than 5% from several kinds of micro surface nonuniformity which is much smaller than other research. Otherwise, we also calculated emittance growth combining with Monte Carlo method and PIC simulation, experiments of emission uniformity and emittance measurement are going to be carried out separately.

Keywords: thermal cathode, electron emission fluctuation, intrinsic emittance, surface nonuniformity, cathode lifetime

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Authors: Xinyu Wei, Mingming Peng, Kenji Kamiya, Eika Qian

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Iso-stearic acid as a saturated fatty acid with a branched chain shows a low pour point, high oxidative stability and great biodegradability. The industrial production of iso-stearic acid involves first isomerizing unsaturated fatty acids into branched-chain unsaturated fatty acids (BUFAs), followed by hydrogenating the branched-chain unsaturated fatty acids to obtain iso-stearic acid. However, the production yield of iso-stearic acid is reportedly less than 30%. In recent decades, extensive research has been conducted on branched fatty acids. Most research has replaced acidic clays with zeolites due to their high selectivity, good thermal stability, and renewability. It was reported that isomerization of unsaturated fatty acid occurred mainly inside the zeolite channel. In contrast, the production of by-products like dimer acid mainly occurs at acid sites outside the surface of zeolite. Further, the deactivation of catalysts is attributed to the pore blockage of zeolite. In the present study, micro/mesoporous ZSM-22 zeolites were developed. It is clear that the synthesis of a micro/mesoporous ZSM-22 zeolite is regarded as the ideal strategy owing to its ability to minimize coke formation. Different mesoporosities micro/mesoporous H-ZSM-22 zeolites were prepared through recrystallization of ZSM-22 using sodium hydroxide solution (0.2-1M) with cetyltrimethylammonium bromide template (CTAB). The structure, morphology, porosity, acidity, and isomerization performance of the prepared catalysts were characterized and evaluated. The dissolution and recrystallization process of the H-ZSM-22 microporous zeolite led to the formation of approximately 4 nm-sized mesoporous channels on the outer surface of the microporous zeolite, resulting in a micro/mesoporous material. This process increased the weak Brønsted acid sites at the pore mouth while reducing the total number of acid sites in ZSM-22. Finally, an activity test was conducted using oleic acid as a model compound in a fixed-bed reactor. The activity test results revealed that micro/mesoporous H-ZSM-22 zeolites exhibited a high isomerization activity, reaching >70% selectivity and >50% yield of BUFAs. Furthermore, the yield of oligomers was limited to less than 20%. This demonstrates that the presence of mesopores in ZSM-22 enhances contact between the feedstock and the active sites within the catalyst, thereby increasing catalyst activity. Additionally, a portion of the dissolved and recrystallized silica adhered to the catalyst's surface, covering the surface-active sites, which reduced the formation of oligomers. This study offers distinct insights into the production of iso-stearic acid using a fixed-bed reactor, paving the way for future research in this area.

Keywords: Iso-stearic acid, oleic acid, skeletal isomerization, micro/mesoporous, ZSM-22

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Authors: Etsuo Morishita

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In this paper, we show shallow water in a tin box as an analogous simulation tool for high-speed aerodynamics education and research. It is customary that we use a water tank to create shallow water flow. While a flow in a water tank is not necessarily uniform and is sometimes wavy, we can visualize a clear supercritical flow even when we move a body manually in stationary water in a simple shallow tin box. We can visualize a blunt shock wave around a moving circular cylinder together with a shock pattern around a diamond airfoil. Another interesting analogous experiment is a hydrodynamic shock tube with water and tea. We observe the contact surface clearly due to color difference of the two liquids those are invisible in the real gas dynamics experiment. We first revisit the similarities between high-speed aerodynamics and shallow water hydraulics. Several educational and research experiments are then introduced for engineering students. Shallow water experiments in a tin box simulate properly the high-speed flows.

Keywords: aerodynamics compressible flow, gas dynamics, hydraulics, shock wave

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Authors: So-Jeong Kim, Nak-Kwan Chung, Jintae Kim, Juyoung Yun

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The metal nanoplates are potentially used for electroluminescence enhancement of OLEDs owing to the localized surface plasmon resonance. In our study, enhanced electroluminescence in blue organic light-emitting diodes is demonstrated by incorporating silver nanoplates into poly(3,4-ethylene dioxythiophene):polystyrene sulfonic acid. To have surface plasmon resonance absorption peak matching with photoluminescent (PL) peak of blue, Ag nanoplates with triangular shape are used in this study. Finally, about 30 % enhancement in electroluminescence intensity and current efficiency for blue emission devices is obtained via Ag nanoplates.

Keywords: efficiency enhancement, nanoplate, OLED, surface plasmon resonance

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Authors: Vaibhav Pandey, K. Chattopadhyay, N. C. Santhi Srinivas, Vakil Singh

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Aluminium alloy 7075 consist of different intermetallic precipitate particles MgZn2, CuAl2, which result in heterogeneity of micro structure and influence the corrosion properties of the alloy. Artificial ageing was found to enhance the strength properties, but highly susceptible to stress-corrosion cracking. Various conventional surface modification techniques are developed for improving corrosion properties of aluminum alloys. This led to development of novel surface mechanical attrition treatment (SMAT) technique the so called ultrasonic shot peening which gives nano-grain structure at surface. In the present investigation the influence of surface mechanical attrition treatment on corrosion behavior of aluminum alloy 7075 was studied in 3.5wt% NaCl solution. Two different size of 1 mm and 3 mm steel balls are used as peening media and SMAT was carried out for different time intervals 5, 15 and 30 minutes. Surface nano-grains/nano-crystallization was observed after SMAT. The formation of nano-grain structure was observed for larger size balls with time of treatment and consequent increase in micro strain. As-SMATed sample with 1 mm balls exhibits better corrosion resistance as compared to that of un-SMATed sample. The enhancement in corrosion resistance may be due to formation of surface nano-grain structure which reduced the electron release rate. In contrast the samples treated with 3 mm balls showed very poor corrosion resistance. A decrease in corrosion resistance was observed with increase in the time of peening. The decrease in corrosion resistance in the shotpeened samples with larger diameter balls may due to increase in microstrain and defect density.

Keywords: aluminum alloy 7075, corrosion, SMAT, ultrasonic shot peening, surface nano-grains

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Authors: Elaine Cristina Barboza, Antonio Jaschke Machado

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This paper discusses micrometeorological aspects of the urban climate in three cities in Western São Paulo State: Presidente Prudente, Assis, and Iepê. Particular attention is paid to the method used to estimate the components of the energy balance at the surface. Estimates of convective fluxes showed that the Bowen ratio was an indicator of the local climate and that its magnitude varied between 0.3 and 0.7. Maximum values for the Bowen ratio occurred earlier in Iepê (11:00 am) than in Presidente Prudente (4:00 pm). The results indicate that the Bowen ratio is modulated by the radiation balance at the surface and by different clusters of vegetation.

Keywords: Bowen ratio, medium-sized cities, surface energy balance, urban climate

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Authors: M. L. Ibrahim, A. Abdulhamid

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A surface active molecule synthesized by a rhizobacterial strain Bacillus lentus isolated from Cajanus cajan was investigated. The bioemulsifier was extracted, purified and partially characterized using standard methods. Surface properties of the bioemulsifier were determined by studying the emulsification index, solubility test and stability studies. Partial purification of the bioemulsifier was carried out using FT-IR analysis, Silica-gel column chromatography and thin layer chromatography. GC-MS analysis was carried out to detect the composition and mass of the lipids and esters. The isolate showed an emulsifying activity of 57% and surface activity of 36mm. The stability studies revealed that the bioemulsifier had better stability at temperature of 70oC, 8% pH and 8% NaCl concentration. FT-IR indicated the bioemulsifier to contain peptide and aliphatic chain, TLC revealed the compound to be ninhydrin positive and Column chromatography showed the presence of three amino acids namely; glutamine, valine and cysteine. GC-MS indicated the lipid moiety to contain aliphatic chain ranging from C9-C16 and two major peaks of 1,2-benzenedicarboxylic acid diethyl octyl ester. Therefore, surface active agent from Bacillus lentus can be used effectively in a wide range of applications such as in MEOR and in the biosynthesis of plasticizers for industrial uses.

Keywords: Bacillus lentus, bioemulsifiers, phthalic acid ester, Rhizosphere

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Authors: Kaige Shi, Chao Jiang, Xin Li

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The swirl gripper is an electrically activated noncontact handling device that uses swirling airflow to generate a lifting force. This force can be used to pick up a workpiece placed underneath the swirl gripper without any contact. It is applicable, for example, in the semiconductor wafer production line, where contact must be avoided during the handling and moving of a workpiece to minimize damage. When a workpiece levitates underneath a swirl gripper, the gap height between them is crucial for safe handling. Therefore, in this paper, we propose a method to estimate the levitation gap height by detecting pressure at two points. The method is based on theoretical model of the swirl gripper, and has been experimentally verified. Furthermore, the force between the gripper and the workpiece can also be estimated using the detected pressure. As a result, the nonlinear relationship between the force and gap height can be linearized by adjusting the rotating speed of the fan in the swirl gripper according to the estimated force and gap height. The linearized relationship is expected to enhance handling stability of the workpiece.

Keywords: swirl gripper, noncontact handling, levitation, gap height estimation

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Authors: Tamás Mankovits, Dávid Huri, Imre Kállai, Imre Kocsis, Tamás Szabó

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Non-linear FEM calculations are indispensable when important technical information like operating performance of a rubber component is desired. Rubber bumpers built into air-spring structures may undergo large deformations under load, which in itself shows non-linear behavior. The changing contact range between the parts and the incompressibility of the rubber increases this non-linear behavior further. The material characterization of an elastomeric component is also a demanding engineering task. In this paper, a comprehensive investigation is introduced including laboratory measurements, mesh density analysis and complex finite element simulations to obtain the load-displacement curve of the chosen rubber bumper. Contact and friction effects are also taken into consideration. The aim of this research is to elaborate an FEM model which is accurate and competitive for a future shape optimization task.

Keywords: rubber bumper, finite element analysis, compression test, Mooney-Rivlin material model

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Authors: Anissa Mary Thomas Thattil, Nancy Angeline Gnanaselvam, B. Ramakrishna Goud

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Faecal sludge management (FSM) is an unorganized sector, and in India, there is an absence of regulations regarding the collection, transport, treatment, and disposal of faecal sludge. FSM has a high degree of occupational hazards that need to be thoroughly understood in order to shape effective solutions. On-field observations of five FSM operations were conducted in Anekal Taluk of southern Karnataka. All five of the FSM operations were privately owned and snowball method of sampling was employed. Two types of FS operations observed were: mechanical emptying involving direct human contact with faecal sludge and mechanical emptying without direct human contact with faecal sludge. Each operation was manned by 3-4 faecal sludge operators (FSOs). None of the observed FSOs used personal protective equipment. According to the WHO semi-quantitative risk assessment, the very high risk occupational hazards identified were dermal contact with faecal sludge, inhalation of toxic gases, and social stigma. The high risk hazards identified were trips and falls, injuries, ergonomic hazards, substance abuse, and mental health problems. In all five FSM operations, the collected faecal sludge was discharged untreated onto abandoned land. FSM in India is fraught with occupational and environmental hazards which need to be urgently addressed. This includes formalizing the institution of FSM, contextualized behaviour change communication, capacity building of local bodies, awareness programmes among agriculturists and FSOs, and designation of sites for the safe harnessing of faecal sludge as soil nutrient.

Keywords: faecal sludge, faecal sludge management, FSM, occupational hazards, sanitation

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Authors: Damir Latypov

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A closed-form solution for 4-D double surface integrals arising in boundary integrals equations of a potential theory is obtained for arbitrary coplanar polygonal surfaces. The solution method is based on the construction of exact differential forms followed by the application of Stokes' theorem for each surface integral. As a result, the 4-D double surface integral is reduced to a 2-D double line integral. By an appropriate change of variables, the integrand is transformed into a separable function of integration variables. The closed-form solutions to the corresponding 1-D integrals are readily available in the integration tables. Previously closed-form solutions were known only for the case of coincident triangle surfaces and coplanar rectangles. Solutions for these cases were obtained by surface-specific ad-hoc methods, while the present method is general. The method also works for non-polygonal surfaces. As an example, we compute in closed form the 4-D integral for the case of coincident surfaces in the shape of a circular disk. For an arbitrarily shaped surface, the proposed method provides an efficient quadrature rule. Extensions of the method for non-coplanar surfaces and other than 1/R integral kernels are also discussed.

Keywords: boundary integral equations, differential forms, integration, stokes' theorem

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Authors: M. Bouinoun, M. Bouhadef

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The present study is concerned with the problem of determining the shape of the free surface flow in a hydraulic channel which has an uneven bottom. For the mathematical formulation of the problem, the fluid of the two-dimensional irrotational steady flow in water is assumed inviscid and incompressible. The solutions of the nonlinear problem are obtained by using the usual conformal mapping theory and Hilbert’s technique. An experimental study, for comparing the obtained results, has been conducted in a hydraulic channel (subcritical regime and supercritical regime).

Keywords: free-surface flow, experiments, numerical method, uneven bottom, supercritical regime, subcritical regime

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Authors: Surajit Das Barman, Rakibuzzaman Shah, Apurv Kumar

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Bushfire is known as one of the ascendant factors to create pyrocumulus thundercloud that causes the ignition of new fires by pyrocumulonimbus (pyroCb) lightning strikes and creates major losses of lives and property worldwide. A conceptual model-based risk planning would be beneficial to predict the lightning striking zones on the surface of the earth underneath the pyroCb thundercloud. PyroCb thundercloud can generate both positive cloud-to-ground (+CG) and negative cloud-to-ground (-CG) lightning in which +CG tends to ignite more bushfires and cause massive damage to nature and infrastructure. In this paper, a simple line charge structured thundercloud model is constructed in 2-D coordinates using the method of image charge to predict the probable +CG lightning striking zones on the earth’s surface for two conceptual thundercloud charge configurations: titled dipole and conventional tripole structure with excessive lower positive charge regions that lead to producing +CG lightning. The electric potential and surface charge density along the earth’s surface for both structures via continuously adjusting the position and the charge density of their charge regions is investigated. Simulation results for tilted dipole structure confirm the down-shear extension of the upper positive charge region in the direction of the cloud’s forward flank by 4 to 8 km, resulting in negative surface density, and would expect +CG lightning to strike within 7.8 km to 20 km around the earth periphery in the direction of the cloud’s forward flank. On the other hand, the conceptual tripole charge structure with enhanced lower positive charge region develops negative surface charge density on the earth’s surface in the range |x| < 6.5 km beneath the thundercloud and highly favors producing +CG lightning strikes.

Keywords: pyrocumulonimbus, cloud-to-ground lightning, charge structure, surface charge density, forward flank

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Authors: Khanh To Duc, Monica Chiogna, Gianfranco Adimari

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With three diagnostic categories, assessment of the performance of diagnostic tests is achieved by the analysis of the receiver operating characteristic (ROC) surface, which generalizes the ROC curve for binary diagnostic outcomes. The volume under the ROC surface (VUS) is a summary index usually employed for measuring the overall diagnostic accuracy. When the true disease status can be exactly assessed by means of a gold standard (GS) test, unbiased nonparametric estimators of the ROC surface and VUS are easily obtained. In practice, unfortunately, disease status verification via the GS test could be unavailable for all study subjects, due to the expensiveness or invasiveness of the GS test. Thus, often only a subset of patients undergoes disease verification. Statistical evaluations of diagnostic accuracy based only on data from subjects with verified disease status are typically biased. This bias is known as verification bias. Here, we consider the problem of correcting for verification bias when continuous diagnostic tests for three-class disease status are considered. We assume that selection for disease verification does not depend on disease status, given test results and other observed covariates, i.e., we assume that the true disease status, when missing, is missing at random. Under this assumption, we discuss several solutions for ROC surface analysis based on imputation and re-weighting methods. In particular, verification bias-corrected estimators of the ROC surface and of VUS are proposed, namely, full imputation, mean score imputation, inverse probability weighting and semiparametric efficient estimators. Consistency and asymptotic normality of the proposed estimators are established, and their finite sample behavior is investigated by means of Monte Carlo simulation studies. Two illustrations using real datasets are also given.

Keywords: imputation, missing at random, inverse probability weighting, ROC surface analysis

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Authors: K. N. Umesh

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Wood Polymer Composites (WPC) were synthesized artificially by combining polypropylene, wood and resin. It is difficult to obtain a good surface finish by conventional machining on WPC because of material degradation due to excessive heat generated during the process. In order to preserve the material property and deliver a better surface finish and accuracy, a proper solution is devised for the machining of wood composites at low temperature. This research focuses on studying the effects of parameters of cryogenic machining on sawdust incorporated polypropylene composite material, in view of evolving the most suitable composition and an appropriate combination of process parameters. The machining characteristics of the six different compositions of WPC were evaluated by analyzing the trend. An attempt is made to determine proper combinations material composition and process control parameters, through process capability studies. A WPC of 80%-wood (saw dust particles), 20%-polypropylene and 0%-resin was found to be the best alternative for obtaining the best surface finish under cryogenic machining conditions.

Keywords: Cryogenic Machining, Process Capability, Surface Finish, Wood Polymer Composites

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Authors: Chris Suma, Yingcai Xiao

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This paper presents Parallel Coordinates on a Spiral Surface (PCoSS), a parallel coordinate based interactive visualization method for high-dimensional data, and a test implementation of the method. Plots generated by the test system are compared with those generated by XDAT, a software implementing traditional parallel coordinates. Traditional parallel coordinate plots can be cluttered when the number of data points is large or when the dimensionality of the data is high. PCoSS plots display multivariate data on a 3D spiral surface and allow users to see the whole picture of high-dimensional data with less cluttering. Taking advantage of the 3D display environment in PCoSS, users can further reduce cluttering by zooming into an axis of interest for a closer view or by moving vantage points and by reorienting the viewing angle to obtain a desired view of the plots.

Keywords: human computer interaction, parallel coordinates, spiral surface, visualization

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Authors: Omid Moradi, Mostafa Rajabi

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Graphene oxide (GO), reduced graphene oxide (rGO), multi-walled carbon nanotubes MWCNT), multi-walled carbon nanotube functionalized carboxyl (MWCNT-COOH), and multi-walled carbon nanotube functionalized thiol (MWCNT-SH) were used as efficient adsorbents for the rapid removal two dyes methyl orange (MO) and malachite green (MG) from the aqueous phase. The impact of several influential parameters such as initial dye concentrations, contact time, temperature, and initial solution pH was well studied and optimized. The optimize time for adsorption process of methyl orange dye on GO, rGO, MWCNT, MWCNT-COOH, and MWCNT-SH surfaces were determined at 100, 100, 60, 25, and 60 min, respectively and The optimize time for adsorption process of malachite green dye on GO, rGO, MWCNT, MWCNT-COOH, and MWCNT-SH surfaces were determined at 100, 100, 60, 15, and 60 min, respectively. The maximum removal efficiency for methyl orange dye by GO, rGO, MWCNT, MWCNT-COOH, and MWCNT-SH surfaces were occurred at optimized pH 3, 3, 6, 2, and 6 of aqueous solutions, respectively and for malachite green dye were occurred at optimized pH 3, 3, 6, 9, and 6 of aqueous solutions, respectively. The effect of temperature showed that adsorption process of malachite green dye on GO, rGO, MWCNT, and MWCNT-SH surfaces were endothermic and for adsorption process of methyl orange dye on GO, rGO, MWCNT, and MWCNT-SH surfaces were endothermic but while adsorption of methyl orange and malachite green dyes on MWCNT-COOH surface were exothermic.On increasing the initial concentration of methyl orange dye adsorption capacity on GO surface was decreased and on rGO, MWCNT, MWCNT-COOH, and MWCNT-SH surfaces were increased and with increasing the initial concentration of malachite green dye on GO, rGO, MWCNT, MWCNT-COOH, and MWCNT-SH surfaces were increased.

Keywords: adsorption, graphene oxide, reduced graphene oxide, multi-walled carbon nanotubes, methyl orange, malachite green, removal

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Authors: Srinivasa Reddy Mallampati, Min Hee Park, Soo Mim Cho, Sung Hyeon Yoon

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One of the issues of End of Life Vehicles (ELVs) recycling promotion is technology for the appropriate treatment of automotive shredder residue (ASR). Owing to its high heterogeneity and variable composition (plastic (23–41%), rubber/elastomers (9–21%), metals (6–13%), glass (10–20%) and dust (soil/sand) etc.), ASR can be classified as ‘hazardous waste’, on the basis of the presence of heavy metals (HMs), PCBs, BFRs, mineral oils, etc. Considering their relevant concentrations, these metals and plastics should be properly recovered for recycling purposes before ASR residues are disposed of. Brominated flame retardant additives in ABS/HIPS and PVC may generate dioxins and furans at elevated temperatures. Moreover, these BFRs additives present in plastic materials may leach into the environment during landfilling operations. ASR thermal process removes some of the organic material but concentrates, the heavy metals and POPs present in the ASR residues. In the present study, Fe/Ca/CaO nanoparticle assisted ozone treatment has been found to selectively hydrophilize the surface of ABS/HIPS and PVC plastics, enhancing its wettability and thereby promoting its separation from ASR plastics by means of froth flotation. The water contact angles, of ABS/HIPS and PVC decreased, about 18.7°, 18.3°, and 17.9° in ASR respectively. Under froth flotation conditions at 50 rpm, about 99.5% and 99.5% of HIPS in ASR samples sank, resulting in a purity of 98% and 99%. Furthermore, at 150 rpm a 100% PVC separation in the settled fraction, with 98% of purity in ASR, respectively. Total recovery of non-ABS/HIPS and PVC plastics reached nearly 100% in the floating fraction. This process improved the quality of recycled ASR plastics by removing surface contaminants or impurities. Further, a hybrid ball-milling and with Fe/Ca/CaO nanoparticle froth flotation process was established for the recovery of HMs from ASR. After ball-milling with Fe/Ca/CaO nanoparticle additives, the flotation efficiency increased to about 55 wt% and the HMs recovery were also increased about 90% for the 0.25 mm size fractions of ASR. Coating with Fe/Ca/CaO nanoparticles associated with subsequent microbubble froth flotation allowed the air bubbles to attach firmly on the HMs. SEM–EDS maps showed that the amounts of HMs were significant on the surface of the floating ASR fraction. This result, along with the low HM concentration in the settled fraction, was confirmed by elemental spectra and semi-quantitative SEM–EDS analysis. Developed hybrid preferential hazardous plastics and metals separation process from ASR is a simple, highly efficient, and sustainable procedure.

Keywords: end of life vehicles shredder residue, hazardous plastics, nanoparticle froth flotation, separation process

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Authors: N. Reppas, Y. L. Gui, B. Wetenhall, C. T. Davie, J. Ma

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A theoretical constitutive model describing the stress-strain behavior of rock subjected to different confining pressures is presented. A bounding surface plastic model with hardening effects is proposed which includes the effect of temperature drop. The bounding surface is based on a mapping rule and the temperature effect on rock is controlled by Poisson’s ratio. Validation of the results against available experimental data is also presented. The relation of deviatoric stress and axial strain is illustrated at different temperatures to analyze the effect of temperature decrease in terms of stiffness of the material.

Keywords: bounding surface, cooling of rock, plasticity model, rock deformation, elasto-plastic behavior

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Authors: Nour El Houda Arabi, Aicha Iratni, Talaighil Razika, Bruno Capoen, Mohamed Bouazaoui

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In this paper, we report the effect of the calcination temperature and SiO2 addition on structural, optical and hydrophilicity of TiO2 films deposited by deep-coating sol-gel process. XRD investigation of the structural TiO2 films with increasing the temperature calcination, reveals that rutile phase will appear for the high temperature (>1000°C). However, the addition of SiO2 relate the densification of TiO2 films. Ellipsometric and UV-visible measure show that the refractive index grow with increasing temperature, against the film thickness decreases. On the other hand, the addition of SiO2 decreases the refractive index and increases the TiO2 film thickness. Finally, the hydrophilicity is assisted by contact angle measurement. It is found that addition of 50% of SiO2 to TiO2 is most effective for reducing the contact angle of water.

Keywords: physical properties, sol, gel, TiO2/SiO2 composite films

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Authors: Ezzaddin Rashid Hussein

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This research investigates the viability of mango seed extract (MSE) using a surfactant to improve oil recovery (EOR). This research examines MSE-based surfactant solutions and compares them to more traditional synthetic surfactants in terms of phase behaviour and interfacial tension. The phase behaviour and interfacial tension of five samples of surfactant solutions with different concentrations were measured. Samples 1 (2.0 g) and 1 (1.5 g) performed closest to the critical micelle concentration (CMC) and displayed the greatest decrease in surface tension, according to the results. In addition, the measurement of IFT, contact angle, and pH, as well as comparison with prior research, highlights the potential environmental benefits of MSMEs as an eco-friendly alternative. It is recommended that additional research be conducted to assess their stability and behaviour under reservoir conditions. Overall, mango seed extract demonstrates promise as a natural and sustainable surfactant for enhancing oil recovery, paving the way for eco-friendly enhanced oil recovery techniques.

Keywords: oil and gas, mango seed powder, surfactants, enhanced oil recovery, interfacial tension IFT, wettability, contacts angle, phase behavior, pH

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Authors: Yohanes Buang, Suwari

Abstract:

Increasing interest of society in use and creation of herbal medicines has encouraged scientists/researchers to establish an ideal method to produce the best quality and quantity of pharmaceutical extracts. To have highest the antioxidative extracts, the method used must be at optimum conditions. Hence, the best method is not only able to provide highest quantity and quality of the isolated pharmaceutical extracts but also it has to be easy to do, simple, fast, and cheap. The characterization of solvents in maceration technique, in present study, involved various variables influencing quantity and quality of the pharmaceutical extracts, such as solvent’s optimum acidity-alkalinity (pH), temperature, concentration, and contact time. The shifting polarity of the solvent by combinations of water with ethanol (70:30) and (50:50) were also performed to completely record the best solvent system in application of maceration technology. Among those three solvents threated within Myrmecodia pendens, as a model of natural product, the results showed that water solvent system with conditions of alkalinity pH, optimum temperature, concentration, and contact time, is the best system to perform the maceration in order to have the highest isolated antioxidative activated extracts. The optimum conditions of the water solvent are at the alkalinity pH 9 up, 30 mg/mL of concentration, 40 min of contact time, 100 °C of temperature, and no ethanol used to replace parts of the water solvent. The present study strongly recommended the best conditions of solvent system to isolate the pharmaceutical extracts of natural products in application of the maceration technology.

Keywords: extracts, herbal medicine, natural product, maceration technique

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Authors: Nader Khalafian, Mohsen Ghaderi

Abstract:

Field observations have revealed many examples of structures which were damaged due to ground surface deformation caused by the faulting phenomena. In this paper some efforts were made in order to estimate the length and location of the ground surface where large displacements were created due to the reverse faulting. This research has conducted in two steps; (1) in the first step, a 2D explicit finite element model were developed using ABAQUS software. A subroutine for Mohr-Coulomb failure criterion with strain softening model was developed by the authors in order to properly model the stress strain behavior of the soil in the fault rapture zone. The results of the numerical analysis were verified with the results of available centrifuge experiments. Reasonable coincidence was found between the numerical and experimental data. (2) In the second step, the effects of the fault dip angle (δ), depth of soil layer (H), dilation and friction angle of sand (ψ and φ) and the amount of fault offset (d) on the soil surface displacement and fault rupture path were investigated. An artificial neural network-based model (ANN), as a powerful prediction tool, was developed to generate a general model for predicting faulting characteristics. A properly sized database was created to train and test network. It was found that the length and location of the zone of displaced ground surface can be accurately estimated using the proposed model.

Keywords: reverse faulting, surface deformation, numerical, neural network

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Authors: Bayoumy Mohamed, Khaled Alam El-Din

Abstract:

In the present study, 24 years of gridded sea level anomalies (SLA) from satellite altimetry and sea surface temperature (SST) from advanced very-high-resolution radiometer (AVHRR) daily data (1993-2016) are used. These data have been used to investigate the sea level rising and warming rates of SST, and their spatial distribution in the Mediterranean Sea. The results revealed that there is a significant sea level rise in the Mediterranean Sea of 2.86 ± 0.45 mm/year together with a significant warming of 0.037 ± 0.007 °C/year. The high spatial correlation between sea level and SST variations suggests that at least part of the sea level change reported during the period of study was due to heating of surface layers. This indicated that the steric effect had a significant influence on sea level change in the Mediterranean Sea.

Keywords: altimetry, AVHRR, Mediterranean Sea, sea level and SST changes, trend analysis

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Authors: Ayu Minamizawa, Jae-Ho Kim, Susumu Yonezawa

Abstract:

Aqueous peroxotitanium acid solution was prepared by the reaction between H₂O₂ solution and TiO₂ fluorinated using F₂ gas. The coating of TiO₂/SiO₂ multilayer on the surface of polycarbonate (PC) resin was carried out step by step using the TEOS solution and aqueous peroxotitanium acid solution. We confirmed each formation of SiO₂ and TiO₂ layer by scanning electron microscopy and energy-dispersive X-ray spectroscopy, and x-ray photoelectron spectroscopy results. The formation of a TiO₂ thin layer on SiO₂ coated on polycarbonate (PC) was carried out at 120 ℃ and for 15 min ~ 3 h with aqueous peroxotitanium acid solution using a hydrothermal synthesis autoclave reactor. The morphology TiO₂ coating layer largely depended on the reaction time, as shown in the results of SEM-EDS analysis. Increasing the reaction times, the TiO₂ layer expanded uniformly. Moreover, the surface fluorination of the SiO₂ layer can promote the formation of the TiO₂ layer on the surface.

Keywords: aqueous peroxotitanium acid solution, photocatalytic activity, polycarbonate, surface fluorination

Procedia PDF Downloads 123