Search results for: orthotropic material

Authors: Narendra Akhadkar, Silvestre Cano, Christophe Gourru

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Injection-molded parts are widely used in power system protection products. One of the biggest challenges in an injection molding process is shrinkage and warpage of the molded parts. All these geometrical variations may have an adverse effect on the quality of the product, functionality, cost, and time-to-market. The situation becomes more challenging in the case of intricate shapes and in mass production using multi-cavity tools. To control the effects of shrinkage and warpage, it is very important to correctly find out the input parameters that could affect the product performance. With the advances in the computer-aided engineering (CAE), different tools are available to simulate the injection molding process. For our case study, we used the MoldFlow insight tool. Our aim is to predict the spread of the functional dimensions and geometrical variations on the part due to variations in the input parameters such as material viscosity, packing pressure, mold temperature, melt temperature, and injection speed. The input parameters may vary during batch production or due to variations in the machine process settings. To perform the accurate product assembly variation simulation, the first step is to perform an individual part variation simulation to render realistic tolerance ranges. In this article, we present a method to simulate part variations coming from the input parameters variation during batch production. The method is based on computer simulations and experimental validation using the full factorial design of experiments (DoE). The robustness of the simulation model is verified through input parameter wise sensitivity analysis study performed using simulations and experiments; all the results show a very good correlation in the material flow direction. There exists a non-linear interaction between material and the input process variables. It is observed that the parameters such as packing pressure, material, and mold temperature play an important role in spread on functional dimensions and geometrical variations. This method will allow us in the future to develop accurate/realistic virtual prototypes based on trusted simulated process variation and, therefore, increase the product quality and potentially decrease the time to market.

Keywords: correlation, molding process, tolerance, sensitivity analysis, variation simulation

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Authors: Meltem Nur Erdöl, Feyzanur Bayrak, Elif Emanetçi, Faik Nüzhet Oktar, Cevriye Kalkandelen, Oğuzhan Gündüz

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Nowadays, the bioceramic graft applications are very important due to the fact that especially European population is getting much older. Consequently, healing approaches for some health problems become more important in the near future. For instance, osteoporosis is one of the reasons for serious hip fractures. Beside these, the traffic accidents playing role increasing of various hip fractures and other bone fractures. Naturally all these are leading the importance developing new bioceramic graft materials. Hydroxyapatite (HA) is one of the leading bioceramics on the market. Beside the high biocompatibility HA bioceramics unfortunately are weak materials for loaded areas. For improvement mechanical properties of HA material, some oxides and metallic powders can be added. In this study, some rare earth oxides like hafnium (IV) oxide (HfO₂) and samarium (III) oxide (Sm₂O₃) are added to HA for improvement of their material characteristics. Thus, compression, microhardness and theoretical density tests are performed. X-ray diffraction patterns are also investigated corresponding x-ray diffraction equipment. At the end, studies of scanning electron microscope (SEM) and energy-dispersive x-ray spectroscopy (EDX) are completed. All values were compared with past BHA and various composites.

Keywords: biocomposite, hafnium oxide, hydroxyapatite, nanotechnology, samarium oxide

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Authors: Kumator Josiphiah Taku

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Sustainability in construction is essential to the economic construction and can be achieved by the use of locally available construction materials. This research work, thus, uses locally available materials –calcined clay and Sandcrete SPR-300 superplasticizer in the production of Self Compacting Concrete (SCC) by investigating the correlation between the superplasticizer dosage and the fresh and hardened states properties of a grade 50 SCC made by incorporating a Calcined Clay (CC) – Portland Limestone Cement (PLC) blend as the cementitious matter at 20% replacement of PLC with CC and using CC as filler. The superplasticizer dosage was varied from 0.4 to 3.0% by weight of cementitious material and the slump, v-funnel, L-box and strength parameters investigated. The result shows a positive correlation between the increased dosage of the superplasticizer and the fresh and hardened states properties of the SCC up to 2% dosage. The J¬Spread¬, t¬500J¬, Slump flow, L-box H¬2¬/H¬1 ¬ratio and strength, all increases with SP dosage while the V-funnel flow decreased with SP dosage. Overall, SP ratio of 0.5 to 2.0 can be used in improving the properties of SCC produced using calcined clay both as filler and cementitious material.

Keywords: calcined clay, compressive strength, fresh-state properties of SCC, self compacting concrete, superplasticizer dosage

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Authors: Ahmed M. Ashteyat

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Artificial Neural Network (ANN) models have been widely used in material modeling, inter-correlations, as well as behavior and trend predictions when the nonlinear relationship between system parameters cannot be quantified explicitly and mathematically. In this paper, ANN was used to predict the residual modulus of elasticity (RME) of self compacted concrete (SCC) damaged by heat. The ANN model was built, trained, tested and validated using a total of 112 experimental data sets, gathered from available literature. The data used in model development included temperature, relative humidity conditions, mix proportions, filler types, and fiber type. The result of ANN training, testing, and validation indicated that the RME of SCC, exposed to different temperature and relative humidity levels, could be predicted accurately with ANN techniques. The reliability between the predicated outputs and the actual experimental data was 99%. This show that ANN has strong potential as a feasible tool for predicting residual elastic modulus of SCC damaged by heat within the range of input parameter. The ANN model could be used to estimate the RME of SCC, as a rapid inexpensive substitute for the much more complicated and time consuming direct measurement of the RME of SCC.

Keywords: residual modulus of elasticity, artificial neural networks, self compacted-concrete, material modeling

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Authors: Makhlouf Mourad, Messabih Sidi Mohamed, Bouchher Omar, Houali Farida, Benrachedi Khaled

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Mesoporous materials are very commonly used as adsorbent materials for removing phenolic compounds. However, the adsorption mechanism of these compounds is still poorly controlled. However, understanding the interactions mesoporous materials/adsorbed molecules is very important in order to optimize the processes of liquid phase adsorption. The difficulty of synthesis is to keep an orderly and cubic pore structure and achieve a homogeneous surface modification. The grafting of Si(CH₃)₃ was chosen, to transform hydrophilic surfaces hydrophobic surfaces. The aim of this work is to study the kinetics and thermodynamics of two volatile organic compounds VOC phenol (PhOH) and P hydroxy benzoic acid (4AHB) on a mesoporous material of type MCM-48 grafted with an organosilane of the Trimethylchlorosilane (TMCS) type, the material thus grafted or functionalized (hereinafter referred to as MCM-48-G). In a first step, the kinetic and thermodynamic study of the adsorption isotherms of each of the VOCs in mono-solution was carried out. In a second step, a similar study was carried out on a mixture of these two compounds. Kinetic models (pseudo-first order, pseudo-second order) were used to determine kinetic adsorption parameters. The thermodynamic parameters of the adsorption isotherms were determined by the adsorption models (Langmuir, Freundlich). The comparative study of adsorption of PhOH and 4AHB proved that MCM-48-G had a high adsorption capacity for PhOH and 4AHB; this may be related to the hydrophobicity created by the organic function of TMCS in MCM-48-G. The adsorption results for the two compounds using the Freundlich and Langmuir models show that the adsorption of 4AHB was higher than PhOH. The values ​​obtained by the adsorption thermodynamics show that the adsorption interactions for our sample with the phenol and 4AHB are of a physical nature. The adsorption of our VOCs on the MCM-48 (G) is a spontaneous and exothermic process.

Keywords: adsorption, kinetics, isotherm, mesoporous materials, Phenol, P-hydroxy benzoique acid

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Authors: M. L. W. P. De Silva, R. A. C. Rabel, N. Smith, L. McIntyre, T. J Parkinson, K. A. N. Wijayawardhane

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Curricular integration is an important concept in medical education for developing students’ ability to create connections between different medical disciplines. Problem-Based Learning (PBL) is one of the vehicles through which such integration can be achieved. During the recent review of the veterinary curriculum at the University of Peradeniya, a series of courses in Integrative Veterinary Science (IVS) were introduced, in which PBL was the primary teaching methodology. The objectives of this study were to evaluate students’ opinions on PBL as a teaching method: it should be noted that, within the context of secondary and tertiary education in Sri Lanka, this would be an entirely novel learning experience for the students. Opinions were sought at the conclusion of IVS sessions where students of semesters 2, 4, 6, and 7 (of an 8-semester program) were exposed to a two, 2-hour PBL-based case scenario. The PBL-based case scenario in semesters 2, 4, and 7 were delivered using material previously developed by an experienced PBL practitioner, whilst material for semester 6 was prepared de novo by a less experienced practitioner. Each student (semesters 2: n=38, 4: n=37, 6: n=55, and 7: n=40) completed a questionnaire which asked whether: (i) the course had improved their critical thinking skills; (ii) the learning environment was sufficiently comfortable to express/share student’s opinion; (iii) there was sufficient facilitator guidance; (iv) the online study environment enhanced learning; and (v) the students were overall satisfied with the PBL approach and IVS concept. Responses were given on a 5-point Likert-scale (strongly agree (SA), agree (A), neutral (N), disagree (D), and strongly disagree (SD)). SA and A responses were summed to provide an overall ‘satisfactory’ response. Results were subjected to frequency-distribution statistical analysis. A total of 88.5% of students gave SA+A scores to their overall satisfaction. The proportion of SA+A scores differed between different semesters, such that 95% of semester 2, 4, and 7 students gave SA+A scores, whereas only 69% of semester 6 students did so for their respective sessions. Overall, 96% of the students gave SA+A scores to the question relating to the improvement of critical thinking skills: semester 6 students’ scores were marginally, but not significantly, lower (91% SA+A) than those in other semesters. The difference of scores between semester 6 and the other semesters may be attributed to the different PBL-material used and/or the different experience levels of the practitioners that developed the study material. The use of PBL as a means of teaching IVS curriculum-integration courses was well-received by the students in terms of their overall satisfaction and their perceptions of improved critical thinking skills. Importantly, this was achieved in the face of a methodology that was entirely novel to the students. Finally, the delivery of the PBL medium was readily mastered by the practitioner to whom it was also a novel methodology.

Keywords: critical thinking skills, integration, problem based learning, veterinary education

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Authors: Delva Richard, Zahibo Narcisse, Yalciner Ahmet

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The Republic of Haiti is one of the poor countries of the world, therefore the authorities must make choices to provide timely solutions to the many difficulties that this Caribbean country is experiencing. There is a very acute lack of scientific research to study natural phenomena in depth. A working group meeting was established under the aegis of the World Bank, UNESCO and the authorities, to study the level of exposure of the Hispaniola. The devastating earthquake of August 2021 killed about 2100 and caused massive material damage; and the 14 12 January 2010 killed more than 250,000 people and caused massive material damage, the evidence of which is still 11 years later. In this paper we want to contribute to the assessment of the risk of tsunami on the southern peninsula of the Republic of Haiti. For the realization of this work we have the bathymetric and topographic data of very good qualities from the private measurement campaigns that we have combined with GEBCO for the inundation grids. We use two numerical models MOST and NAMI DANCE for the calculation of the parameters required in any tsunami risk assessment.

Keywords: modélisation numérique, ondes longues océaniques, bathymetrie, evaluation risque, tsunamis

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Authors: Vahid Ramezankhani, Keith J. Stevenson, Stanislav. S. Fedotov

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Lithium-ion batteries (LIBs) play a pivotal role in achieving the key objective “zero-carbon emission” as countries agreed to reach a 1.5ᵒC global warming target according to the Paris agreement. Nowadays, due to the tremendous mobile and stationary consumption of small/large-format LIBs, the demand and consequently the price for such energy storage devices have been raised. The aforementioned challenges originate from the shrinkage of the major applied critical materials in these batteries, such as cobalt (Co), nickel (Ni), Lithium (Li), graphite (G), and manganese (Mn). Therefore, it is imperative to consider alternative elements to address issues corresponding to the limitation of resources around the globe. Potassium (K) is considered an effective alternative to Li since K is a more abundant element, has a higher operating potential, a faster diffusion rate, and the lowest stokes radius in comparison to the closest neighbors in the periodic table (Li and Na). Among all reported materials for metal-ion batteries, some of them possess the general formula AMXO4L [A = Li, Na, K; M = Fe, Ti, V; X = P, S, Si; L= O, F, OH] is of potential to be applied both as anode and cathode and enable researchers to investigate them in the full symmetric battery format. KTiPO4F (KTP structural material) has been previously reported by our group as a promising cathode with decent electronic properties. Herein, we report a synthesis, crystal structure characterization, morphology, as well as K-ion storage properties of KTiPO4F. Our investigation reveals that KTiPO4F delivers discharge capacity > 150 mAh/g at 26.6 mA/g (C/5 current rate) in the potential window of 0.001-3 V. Surprisingly, the cycling performance of C-KTiPO4F//K cell is stable for 1000 cycles at 130 mA/g (C current rate), presenting capacity > 130 mAh/g. More interestingly, we achieved to assemble full symmetric batteries where carbon-coated KTiPO4F serves as both negative and positive electrodes, delivering >70 mAh/g in the potential range of 0.001-4.2V.

Keywords: anode material, potassium battery, chemical characterization, electrochemical properties

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Authors: Ella C. Linganiso, Bonex W. Mwakikunga, Trilock Singh, Sanjay Mathur, Odireleng M. Ntwaeaborwa

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The use of nanostructured semiconducting material to catalyze degradation of environmental pollutants still receives much attention to date. One of the desired characteristics for pollutant degradation under ultra-violet visible light is the materials with extended carrier charge separation that allows for electronic transfer between the catalyst and the pollutants. In this work, zinc oxide n-type semiconductor vertically aligned structures were fabricated on silicon (100) substrates using the chemical bath deposition method. The as-synthesized structures were treated with nickel and sulphur. X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy were used to characterize the phase purity, structural dimensions and elemental composition of the obtained structures respectively. Photoluminescence emission measurements showed a decrease in both the near band edge emission as well as the defect band emission upon addition of nickel and sulphur with different concentrations. This was attributed to increased charger-carrier-separation due to the presence of Ni-S material on ZnO surface, which is linked to improved charge transfer during photocatalytic reactions.

Keywords: Carrier-charge-separation, nickel, photoluminescence, sulphur, zinc oxide

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Authors: Farah Benbouabdellah

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This research examines the shifting portrayal of tigers in visual media, particularly cinema, to explore how cultural, political, and ecological perspectives influence animal symbolism. Through an interdisciplinary approach combining film studies, anthropology, art history, and material culture, this study investigates tiger representations in static and moving images, from early art forms to 20th-century films. The research highlights how the film has perpetuated, transformed, and politicised tiger imagery across contexts by analysing colonialism, identity, and ecological change themes. With a comprehensive focus on Indian and Western cinema, this study illustrates the tiger's enduring role as a cultural symbol and its impact on visual narratives, exploring techniques in cinematography, audience reception, and narratives that helped shape the animal's iconic status. This research aims to provide a comprehensive view of tiger representations in media, addressing the intersection of animal symbolism and sociocultural values across historical and regional landscapes.

Keywords: tiger representation, visual media, anthropology media, material culture, film studies, comparative analysis

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Authors: Bolatbek Rysbaiuly, Nazerke Rysbayeva, Aigerim Rysbayeva

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Relevance: Energy saving elevated to public policy in almost all developed countries. One of the areas for energy efficiency is improving and tightening design standards. In the tie with the state standards, make high demands for thermal protection of buildings. Constructive arrangement of layers should ensure normal operation in which the humidity of materials of construction should not exceed a certain level. Elevated levels of moisture in the walls can be attributed to a defective condition, as moisture significantly reduces the physical, mechanical and thermal properties of materials. Absence at the design stage of modeling the processes occurring in the construction and predict the behavior of structures during their work in the real world leads to an increase in heat loss and premature aging structures. Method: To solve this problem, widely used method of mathematical modeling of heat and mass transfer in materials. The mathematical modeling of heat and mass transfer are taken into the equation interconnected layer [1]. In winter, the thermal and hydraulic conductivity characteristics of the materials are nonlinear and depends on the temperature and moisture in the material. In this case, the experimental method of determining the coefficient of the freezing or thawing of the material becomes much more difficult. Therefore, in this paper we propose an approximate method for calculating the thermal conductivity and moisture permeability characteristics of freezing or thawing material. Questions. Following the development of methods for solving the inverse problem of mathematical modeling allows us to answer questions that are closely related to the rational design of fences: Where the zone of condensation in the body of the multi-layer fencing; How and where to apply insulation rationally his place; Any constructive activities necessary to provide for the removal of moisture from the structure; What should be the temperature and humidity conditions for the normal operation of the premises enclosing structure; What is the longevity of the structure in terms of its components frost materials. Tasks: The proposed mathematical model to solve the following problems: To assess the condition of the thermo-physical designed structures at different operating conditions and select appropriate material layers; Calculate the temperature field in a structurally complex multilayer structures; When measuring temperature and moisture in the characteristic points to determine the thermal characteristics of the materials constituting the surveyed construction; Laboratory testing to significantly reduce test time, and eliminates the climatic chamber and expensive instrumentation experiments and research; Allows you to simulate real-life situations that arise in multilayer enclosing structures associated with freezing, thawing, drying and cooling of any layer of the building material.

Keywords: energy saving, inverse problem, heat transfer, multilayer walling

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Authors: Leonard Chimaobi Agim, Charles Arinzechukwu Igwe, Emmanuel Uzoma Onweremadu, Gabreil Osuji

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Soil erosion has been linked to stream sedimentation, ecosystem degradation, and loss of soil nutrients. A study was conducted to evaluate the effect of some organic amendment on sediment yield, splash loss, and runoff of soils of selected parent materials in southeastern Nigeria. A total of 20 locations, five from each of four parent materials namely: Asu River Group (ARG), Bende Ameki Group (BAG), Coastal Plain Sand (CPS) and Falsebedded Sandstone (FBS) were used for the study. Collected soil samples were analyzed with standard methods for the initial soil properties. Rainfall simulation at an intensity of 190 mm hr-1was conducted for 30 minutes on the soil samples at both the initial stage and after amendment to obtain erosion parameters. The influence of parent material on sediment yield, splash loss and runoff based on rainfall simulation was tested for using one way analyses of variance, while the influence of organic material and their combinations were a factorially fitted in a randomized complete block design. The organic amendments include; goat dropping (GD), poultry dropping (PD), municipal solid waste (MSW) and their combinations (COA) applied at four rates of 0, 10, 20 and 30 t ha-1 respectively. Data were analyzed using analyses of variance suitable for a factorial experiment. Significant means were separated using LSD at 5 % probability levels. Result showed significant (p ≤ 0.05) lower values of sediment yield, splash loss and runoff following amendment. For instance, organic amendment reduced sediment yield under wet and dry runs by 12.91 % and 26.16% in Ishiagu, 40.76% and 45.67%, in Bende, 16.17% and 50% in Obinze and 22.80% and 42.35% in Umulolo respectively. Goat dropping and combination of amendment gave the best results in reducing sediment yield.

Keywords: organic amendment, parent material, rainfall simulation, soil erosion

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Authors: D. M. Eric, D. Milosevic, F. D. Eric

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Concurrent engineering technologies are a modern concept in manufacturing engineering. One of the key goals in designing modern technological processes is further reduction of production costs, both in the prototype and the preparatory part, as well as during the serial production. Thanks to many segments of concurrent engineering, these goals can be accomplished much more easily. In this paper, we give an overview of the advantages of using modern software simulations in relation to the classical aspects of designing technological processes of metal deformation. Significant savings are achieved thanks to the electronic simulation and software detection of all possible irregularities in the functional-working regime of the technological process. In order for the expected results to be optimal, it is necessary that the input parameters are very objective and that they reliably represent the values ​of these parameters in real conditions. Since it is a metal deformation treatment here, the particularly important parameters are the coefficient of internal friction between the working material and the tools, as well as the parameters related to the flow curve of the processing material. The paper will give a presentation for the experimental determination of some of these parameters.

Keywords: production technologies, metal processing, software simulations, effects of application

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Authors: Pravat Ranjan Pati, Alok Satapathy

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Linz-Donawitz (LD) slag a major solid waste generated in huge quantities during steel making. It comes from slag formers such as burned lime/dolomite and from oxidizing of silica, iron etc. while refining the iron into steel in the LD furnace. Although a number of ways for its utilization have been suggested, its potential as a filler material in polymeric matrices has not yet been explored. The present work reports the possible use of this waste in glass fiber reinforced epoxy composites as a filler material. Hybrid composites consisting of bi-directional e-glass-fiber reinforced epoxy filled with different LD slag content (0, 7.5, 15, 22.5 wt%) are prepared by simple hand lay-up technique. The composites are characterized in regard to their density, porosity, micro-hardness and strength properties. X-ray diffractography is carried out in order to ascertain the various phases present in LDS. This work shows that LD slag, in spite of being a waste, possesses fairly good filler characteristics as it modifies the strength properties and improves the composite micro-hardness of the polymeric resin.

Keywords: characterization, glass-epoxy composites, LD slag, waste utilization

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Authors: Olga Shuvaeva, Tamara Romanova, Sergey Volynkin, Valentina Podolinnaya

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Green chemistry concept is focused on the prevention of environmental pollution caused by human activity. However, there are a lot of contaminated areas in the world which pose a serious threat to ecosystems in terms of their conservation. Therefore in accordance with the principles of green chemistry, it should not be forgotten about the need to clean these areas. Furthermore, the waste material often contains the valuable components, the extraction of which by traditional wet chemical technologies is inefficient both from the economic and environmental protection standpoint. Wherein, the plants may be successfully used to ‘scavenge’ a range of metals from polluted land sites in an approach allowing to carry out both of these processes – phytoremediation and phytomining in conjunction. The goal of the present work was to study bioaccumulation ability of floating macrophytes such as water hyacinth and pondweed toward Hg, Ba, Cd, Mo and Pb as pollutants in aquatic medium and terrestrial plants (birch, reed, and cane) towards gold and silver as valuable components. The peculiarity of ongoing research was that the plants grew under extreme conditions (pH of drainage and pore waters was about 2.5). The study was conducted at the territory of Ursk tailings (Southwestern Siberia, Russia) formed as a result of primary polymetallic ores cyanidation. The waste material is mainly presented (~80%) by pyrite (FeS₂) and barite (BaSO₄), the raw minerals included FeAsS, HgS, PbS, Ag₂S as minor ones. It has been shown that water hyacinth demonstrates high ability to accumulate different metals, and what is especially important – to remove mercury from polluted waters with BCF value more than 1000. As for the gold, its concentrations in reed and cane growing near the waste material were estimated as 500 and 900 μg∙kg⁻¹ respectively. It was also found that the plants can survive under extreme conditions of acidic environment and hence we can assume that there is a principal opportunity to use them for the valuable substances extraction from an area of the mining waste dumps burial.

Keywords: bioaccumulation, gold, heavy metals, mine tailing

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Authors: Panagiotis Roupas, Yota Passia

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This paper aims at establishing an index of design mechanisms - immanent in spatial objects - based on the affective capacity of their material formations. While spatial objects (design objects, buildings, urban configurations, etc.) are regarded as systems composed of interacting parts, within the premises of assemblage theory, their ability to affect and to be affected has not yet been mapped or sufficiently explored. This ability lies in excess, a latent potentiality they contain, not transcendental but immanent in their pre-subjective aesthetic power. As spatial structures are theorized as assemblages - composed of heterogeneous elements that enter into relations with one another - and since all assemblages are parts of larger assemblages, their components' ability to engage is contingent. We thus seek to unfold the mechanisms inherent in spatial objects that allow to the constituent parts of design assemblages to perpetually enter into new assemblages. To map architectural assemblage's affective ability, spatial objects are analyzed in two axes. The first axis focuses on the relations that the assemblage's material and expressive components develop in order to enter the assemblages. Material components refer to those material elements that an assemblage requires in order to exist, while expressive components includes non-linguistic (sense impressions) as well as linguistic (beliefs). The second axis records the processes known as a-signifying signs or a-signs, which are the triggering mechanisms able to territorialize or deterritorialize, stabilize or destabilize the assemblage and thus allow it to assemble anew. As a-signs cannot be isolated from matter, we point to their resulting effects, which without entering the linguistic level they are expressed in terms of intensity fields: modulations, movements, speeds, rhythms, spasms, etc. They belong to a molecular level where they operate in the pre-subjective world of perceptions, effects, drives, and emotions. A-signs have been introduced as intensities that transform the object beyond meaning, beyond fixed or known cognitive procedures. To that end, from an archive of more than 100 spatial objects by contemporary architects and designers, we have created an effective mechanisms index is created, where each a-sign is now connected with the list of effects it triggers and which thoroughly defines it. And vice versa, the same effect can be triggered by different a-signs, allowing the design object to lie in a perpetual state of becoming. To define spatial objects, A-signs are categorized in terms of their aesthetic power to affect and to be affected on the basis of the general categories of form, structure and surface. Thus, different part's degree of contingency are evaluated and measured and finally, we introduce as material information that is immanent in the spatial object while at the same time they confer no meaning; they only convey some information without semantic content. Through this index, we are able to analyze and direct the final form of the spatial object while at the same time establishing the mechanism to measure its continuous transformation.

Keywords: affective mechanisms index, architectural assemblages, a-signifying signs, cartography, virtual

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Authors: Zachary N. Wing

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Compared to autoclave based processes, Resin Transfer Molding (RTM) offers several key advantages. This includes high internal and external complexity, less waste, lower volatile emissions, higher production rates, and excellent surface finish. However, the injection of high pressure-high temperature resin presents a tooling challenge in cases where trapped geometries exist. Tooling materials that can sustain these conditions and be easily removed would expand the use of RTM. We have performed research on developing an RTM suitable tooling material called 'RTMCore' for use in forming trapped geometries. RTMCore tooling materials can withstand the injection of high temperature-high pressure resin but be easily removed with tap water. RTM properties and performance capabilities are reviewed against other washout systems. Our research will cover the preliminary characterization of tooling system properties, mechanical behavior, and initial results from an RTM manufacturing trial. Preliminary results show the material can sustain pressures greater than 13 MPa and temperatures greater than 150°C.

Keywords: RTM, resin transfer molding, trapped geometries, washout tooling

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Authors: B. Kahouadji, L. Guerbous, L. Lamiri, A. Mendoud

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Recently, nanomaterials are developed in the form of nano-films, nano-crystals and nano-pores. Lanthanide phosphates as a material find extensive application as laser, ceramic, sensor, phosphor, and also in optoelectronics, medical and biological labels, solar cells and light sources. Among the different kinds of rare-earth orthophosphates, yttrium orthophosphate has been shown to be an efficient host lattice for rare earth activator ions, which have become a research focus because of their important role in the field of light display systems, lasers, and optoelectronic devices. It is in this context that the 4fn- « 4fn-1 5d transitions of rare earth in insulating materials, lying in the UV and VUV, are the aim of large number of studies .Though there has been a few reports on Eu3+, Nd3+, Pr3+,Er3+, Ce3+, Tm3+ doped YPO4. The 4fn- « 4fn-1 5d transitions of the rare earth dependent to the host-matrix, several matrices ions were used to study these transitions, in this work we are suggesting to study on a very specific class of inorganic material that are orthophosphate doped with rare earth ions. This study focused on the effect of Ce3+ concentration on the structural and optical properties of Ce3+ doped YPO4 yttrium orthophosphate with powder form prepared by the Sol Gel method.

Keywords: YPO4, Ce3+, 4fn- <->4fn-1 5d transitions, scintillator

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Authors: Chandni Rani, S. D. Tiwari

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Ferrihydrite is one of the distinct minerals in the family of oxides, hydroxides and oxyhydroxides of iron. It is a nanocrystalline material. It occurs naturally in different sediments, soil systems and also found in the core of ferritin, an iron storage protien. This material can also be synthesized by suitable chemical methods in laboratories. This is known as less crystalline Iron (III) Oxyhydroxide. Due to its poor crystallinity, there are very broad peaks in x-ray diffraction. Depending on the number of peaks in x-ray diffraction pattern, it is classified as two lines and six lines ferrihydrite. The average crystallite size for these two forms is found to be about 2nm to 5nm. The exact crystal structure of this system is still under debate. Out of these two forms, the six lines ferrihydrite is more ordered in comparison to two lines ferrihydrite. The magnetic behavior of two lines ferrihydrite nanoparticles is somewhat well studied. But the magnetic behavior of six lines ferrihydrite nanoparticles could not attract the attention of researchers much. This motivated us to work on the magnetic properties of six lines ferrihydrite nanoparticles. In this work, we present synthesis, structural characterization and magnetic behavior of 5 nm six lines ferrihydrite nanoparticles. X-ray diffraction and transmission electron microscope are used for structural characterization of this system. Magnetization measurements are performed to fit the data at different temperatures. Then the effect of magnetic moment distribution is also found. All these observations are discussed in detail.

Keywords: nanoparticles, magnetism, superparamagnetism, magnetic anisotropy

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Authors: Tarikayehu Amanuel, Abraham Mohammed

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The production of biodiesel from waste materials is becoming an increasingly important research area in the field of renewable energy. One potential waste material source is avocado, a fruit with a large seed and peel that are typically discarded after consumption. This research aims to investigate the feasibility of using avocado waste as a feedstock for the production of biodiesel. The study focuses on extracting oil from the waste material using the transesterification technique and then characterizing the properties of oil to determine its suitability for conversion to biodiesel. The study was conducted experimentally, and a maximum oil yield of 11.583% (150g of oil produced from 1.295kg of avocado waste powder) was obtained from avocado waste powder at an extraction time of 4hr. An 87% fatty acid methyl ester (biodiesel) conversion was also obtained using a methanol/oil ratio of 6:1, 1.3g NaOH, reaction time 60min, and 65°C reaction temperature. Furthermore, from 145 ml of avocado waste oil, 126.15 ml of biodiesel was produced, indicating a high percentage of conversion (87%). Conclusively, the produced biodiesel showed comparable physical and chemical characteristics to that of standard biodiesel samples considered for the study. The results of this research could help to identify a new source of biofuel production while also addressing the issue of waste disposal in the food industry.

Keywords: biodiesel, avocado, transesterification, soxhlet extraction

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Authors: Khaled Own Mohaisen, Md. Hasan Zahir, Salah U. Al-Dulaijan, Shamsad Ahmad, Mohammed Maslehuddin

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Shape-stabilized phase change materials (ss-PCMs) for energy storage systems were developed using perlite, scoria, and oil ash as a carrier, with polyethylene glycol (PEG) with a molecular weight of 6000 as phase change material (PCM). Physical mixing using simple impregnation of ethanol evaporation technique method was carried out to fabricate the form stabilized PCM. The fabricated PCMs prevent leakage, reduce the supercooling effect and minimize recalescence problems of the PCM. The differential scanning calorimetry (DSC) results show that perlite composite (ExPP) has the highest latent heat of melting and freezing values of (141.6 J/g and 143.7 J/g) respectively, compared with oil ash (OAP) and scoria (SCP) composites. Moreover, ExPP has the highest impregnation ratio, energy storage efficiency, and energy storage capacity compared with OAP and SCP. However, OAP and SCP have higher thermal conductivity values compared to ExPP composites which accelerate the thermal storage response in the composite. These results were confirmed with DSC, and the characteristic of the PCMs was investigated by using XRD and FE-SEM techniques.

Keywords: expanded perlite, oil ash, scoria, energy storage material

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Authors: Amol M. Jadhav, Sharad S. Chudhari, S. S. Khedkar

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This review presents a through survey of research paper work on the experimental analysis, FEM Analysis & simulation of the metal spinning process. In this literature survey all the papers being taken from Elsevier publication and most of the from journal of material processing technology. In a last two decade or so, metal spinning process gradually used as chip less formation for the production of engineering component in a small to medium batch quantities. The review aims to provide include into the experimentation, FEM analysis of various components, simulation of metal spinning process and act as guide for research working on metal spinning processes. The review of existing work has several gaps in current knowledge of metal spinning processes. The evaluation of experiment is thickness strain, the spinning force, the twisting angle, the surface roughness of the conventional & shear metal spinning process; the evaluation of FEM of metal spinning to path definition with sufficient fine mesh to capture behavior of work piece; The evaluation of feed rate of roller, direction of roller,& type of roller stimulated. The metal spinning process has the more flexible to produce a wider range of product shape & to form more challenge material.

Keywords: metal spinning, FEM analysis, simulation of metal spinning, mechanical engineering

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Authors: Joon Sang Kang, Ming Ke, Yongjie Hu

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Controlling heat transfer and thermal properties of materials is important to many fields such as energy efficiency and thermal management of integrated circuits. Significant progress over the past decade has been made to improve material performance through structuring at the nanoscale, however a clear relationship between structure dimensions, interfaces, and thermal properties remains to be established. The main challenge comes from the unknown intrinsic spectral contribution from different phonons. Here, we describe our current progress on quantifying and controlling thermal spectra based on our recently developed technical approach using ultrafast optical spectroscopy. Our work brings further the promise of rational material design to achieve high performance through a synergistic experimental-modeling approach. This approach can be broadly applicable to a wide range of materials and energy systems. In particular, we demonstrate in-situ characterization and tunable thermal properties of 2D van der waals materials through ionic intercalations. The significant impacts of this research in improving the efficiency of thermal energy conversion and management will also be illustrated.

Keywords: energy, mean free path, nanoscale heat transfer, nanostructure, phonons, TDTR, thermoelectrics, 2D materials

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Authors: Hubert Feiglstorfer

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The technique of making terrazzo has been known since ancient times. During the Roman Empire, known as opus signinum, at the time of the Renaissance, known as composto terrazzo marmorino or at the turn of the 19th and 20th centuries, the use of terrazzo experienced a common use in Europe. In Asia, especially in the Himalayas and the Tibetan highlands, a particular floor and roof manufacturing technique is commonly used for about 1500 years, known as arga. The research question in this contribution asks for technical and cultural-historical synergies of these floor-making techniques. The making process of an arga floor shows constructive parallels to the European terrazzo. Surface processing by grinding, burnishing and sealing, in particular, reveals technological similarities. The floor structure itself, on the other hand, shows differences, for example in the use of hydraulic aggregate in the terrazzo, while the arga floor is used without hydraulic material, but the result of both techniques is a tight, water-repellent and shiny surface. As part of this comparative study, the materials, processing techniques and quality features of the two techniques are compared and parallels and differences are analysed. In addition to text and archive research, the methods used are results of material analyses and ethnographic research such as participant observation. Major findings of the study are the investigation of the mineralogical composition of arga floors and its comparison with terrazzo floors. The study of the cultural-historical context in which both techniques are embedded will give insight into technical developments in Europe and Asia, parallels and differences. Synergies from this comparison let possible technological developments in the production, conservation and renovation of European terrazzo floors appear in a new light. By making arga floors without cement-based aggregates, the renovation of historical floors from purely natural products and without using energy by means of a burning process can be considered.

Keywords: European and Asian crafts, material culture, floor making technology, terrazzo, arga, Tibetan building traditions

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Authors: Golam Saklayen, Sheikh Rashel al Ahmed, Ferdous Rahman, Ismail Abu Bakar

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Investigation on Lanthanum Fluoride LaF3 layer embedding Silicon Nanocrystals (Si-NCs) fabricated using a novel one-step chemical method has been reported in this presentation. Application of this material has been tested for low-voltage operating non-volatile memory and Schottkey-junction solar cell. Colloidal solution of Si-NCs in hydrofluoric acid (HF) was prepared from meso-porous silicon by ultrasonic vibration (sonication). This solution prevents the Si-NCs to be oxidized. On a silicon (Si) substrate, LaCl3 solution in HCl is allowed to react with the colloidal solution of prepared Si-NCs. Since this solution contains HF, LaCl3 reacts with HF and produces LaF3 crystals that deposits on the silicon substrate as a layer embedding Si-NCs. This a novel single step chemical way of depositing LaF3 insulating layer embedding Si-NCs. The X-Ray diffraction of the deposited layer shows a polycrystalline LaF3 deposition on silicon. A non-stoichiometric LaF3 layer embedding Si-NCs was found by EDX analysis. The presence of Si-NCs was confirmed by SEM. FTIR spectroscopy of the deposited LaF3 powder also confirmed the presence of Si-NCs. The size of Si-NCs was found to be inversely proportional to the ultrasonic power. After depositing proper contacts on the back of Si and LaF3, the devices have been tested as a non-volatile memory and solar cell. A memory window of 525 mV was obtained at a programming and erasing bias of 2V. The LaF3 films with Si NCs showed strong absorption and was also found to decrease optical transmittance than pure LaF3 film of same thickness. The I-V characteristics of the films showed a dependency on the incident light intensity where current changed under various light illumination. Experimental results show a lot of promise for Si-NCs-embedded LaF3 layer to be used as an insulating layer in MIS devices as well as an photoactive material in Schottkey junction solar cells.

Keywords: silicon nanocrystals (Si NCs), LaF3, colloidal solution, Schottky junction solar cell

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Authors: Ahmet E. Osmanlioglu

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In this study, natural bentonite was used as natural clay material and samples were taken from the Kalecik district in Ankara. In this research, bentonite is the subject of an analysis from standpoint of assessing the basic properties of engineered barriers with respect to the buffer material. Bentonite and sand mixtures were prepared for tests. Some of clay minerals give relatively higher hydraulic conductivity and lower swelling pressure. Generally, hydraulic conductivity of these type clays is lower than <10-12 m/s. The hydraulic properties of clay-sand mixtures are evaluated to design engineered barrier specifications. Hydraulic conductivities of bentonite-sand mixture were found in the range of 1.2x10-10 to 9.3x10-10 m/s. Optimum B/S mixture ratio was determined as 35% in terms of hydraulic conductivity and mechanical stability. At the second stage of this study, all samples were compacted into cylindrical shape molds (diameter: 50 mm and length: 120 mm). The strength properties of compacted mixtures were better than the compacted bentonite. In addition, the larger content of the quartz sand in the mixture has the greater thermal conductivity.

Keywords: engineered barriers, mechanical stability, clay, nuclear waste disposal

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Authors: Javad Someehneshin, Weizhou Quan, Abdelsalam Abugharara, Stephen Butt

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Narrow vein mining (NVM) is exploiting very thin but valuable ore bodies that are uneconomical to extract by conventional mining methods. NVM applies the technique of Sustainable Mining by Drilling (SMD). The SMD method is used to mine stranded, steeply dipping ore veins, which are too small or isolated to mine economically using conventional methods since the dilution is minimized. This novel mining technique uses drilling rigs to extract the ore through directional drilling surgically. This paper is focusing on utilizing the run of the mine tailings and Portland cement as backfill material to support the hanging wall for providing safe mine operation. Cemented paste backfill (CPB) is designed by mixing waste tailings, water, and cement of the precise percentage for optimal outcomes. It is a non-homogenous material that contains 70-85% solids. Usually, a hydraulic binder is added to the mixture to increase the strength of the CPB. The binder fraction mostly accounts for 2–10% of the total weight. In the mining industry, CPB has been improved and expanded gradually because it provides safety and support for the mines. Furthermore, CPB helps manage the waste tailings in an economical method and plays a significant role in environmental protection.

Keywords: backfilling, cement backfill, tailings, Portland cement

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Authors: Pimchanok Puksisuwan, Pitak Laorattanakul, Benya Cherdhirunkorn

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The use of aluminium dross as a raw material for geopolymer synthesis via mechanochemistry method was studied. The geopolymers were prepared using aluminium dross from secondary aluminium industry, fly ash from a biomass power plant and liquid alkaline activators, which is a mixture of sodium silicate solution (Na2SiO3) and sodium hydroxide solution (NaOH) (Na2SiO3/NaOH ratio 4:1, 3:1 and 2:1). Aluminium dross consists mostly of alumina (Al2O3), silicon oxide (SiO2) and aluminium nitride (AlN). The raw materials were mixed and milled using the high energy ball milling method for 5, 10 and 15 minutes in order to reduce the particle size. The milled powders were uniaxially pressed into a cylinder die with the pressure of 2200 psi. The cylinder samples were cured in the sealed plastic bags for 3, 7 and 14 days at the room temperature and 60°C for 24 hour. The mechanical property of geopolymers was investigated. In addition, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis were carried out in order to study the microstructure and phase structures of the geopolymers, respectively. The results showed that aluminium dross could enhance the mechanical property of geopolymers product by mechanochemistry method and meet the TISI requirements.

Keywords: aluminium dross, fly ash, geopolymer, mechanochemistry

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Authors: James Q. Feng

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Pneumatic nebulizers (as variations based on the Collison nebulizer) have been widely used for producing fine aerosol droplets from a liquid material. As qualitatively described by many authors, the basic working principle of those nebulizers involves utilization of the negative pressure associated with an expanding gas jet to syphon liquid into the jet stream, then to blow and shear into liquid sheets, filaments, and eventually droplets. But detailed quantitative analysis based on fluid mechanics theory has been lacking in the literature. The purpose of present work is to investigate the nature of negative pressure distribution associated with compressible gas jet flow in the Collison nebulizer by a computational fluid dynamics (CFD) analysis, using an OpenFOAM® compressible flow solver. The value of the negative pressure associated with a gas jet flow is examined by varying geometric parameters of the jet expansion channel adjacent to the jet orifice outlet. Such an analysis can provide valuable insights into fundamental mechanisms in liquid aspiration process, helpful for effective design of the pneumatic atomizer in the Aerosol Jet® direct-write system for micro-feature, high-aspect-ratio material deposition in additive manufacturing.

Keywords: collison nebulizer, compressible gas jet flow, liquid aspiration, pneumatic atomization

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Authors: Ning Chia

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Each of the three different language texts (Manchu, Russian, and Latin) of the 1689 Treaty of Nerchinsk bore official seals from Imperial Russia and Qing China. These seals have received no academic attention, yet they can reveal a site of a layered and shared material, cultural, political, and diplomatic world of the time in Eastern Eurasia. The very different seal selections from both empires while ratifying the Treaty of Beijing in 1860 have obtained no scholarly advertency either; they can also explicate a tremendously changed relationship with visual and material manifestation. Exploring primary sources in Manchu, Russian, and Chinese languages as well as the images of the visual seals, this study investigates the reasons and purposes of utilizing official seals for the treaty agreement. A refreshed understanding of Russian-Qing diplomacy will be developed by pursuing the following aspects: (i) Analyzing the iconographic meanings of each seal insignia and unearthing a competitive, yet symbols-delivered and seal-generated, 'dialogue' between the two empires (ii) Contextualizing treaty seals within the historical seal cultures, and discovering how domestic seal system in each empire’s political institution developed into treaty-defined bilateral relations (iii) Expounding the seal confiding in each empire’s daily governing routines, and annotating the trust in the seal as a quested promise from the opponent negotiator to fulfill the treaty terms (iv) Contrasting the two seal traditions along two civilization-lines, Eastern vs. Western, and dissecting how the two styles of seal emblems affected the cross-cultural understanding or misunderstanding between the two empires (v) Comprehending the history-making events from the substantial resources such as the treaty seals, and grasping why the seals for the two treaties, so different in both visual design and symbolic value, were chosen in the two relationship eras (vi) Correlating the materialized seal 'expression' and the imperial worldviews based on each empire’s national/or power identity, and probing the seal-represented 'rule under the Heaven' assumption of China and Russian rising role in 'European-American imperialism … centered on East Asia' (Victor Shmagin, 2020). In conclusion, the impact of official seals on diplomatic treaties needs profound knowledge in seal history, insignia culture, and emblem belief to be able to comprehend. The official seals in both Imperial Russia and Qing China belonged to a particular statecraft art in a specific material and visual form. Once utilized in diplomatic treaties, the meticulously decorated and politically institutionalized seals were transformed from the determinant means for domestic administration and social control into the markers of an empire’s sovereign authority. Overlooked in historical practice, the insignia seal created a wire of 'visual contest' between the two rival powers. Through this material lens, the scholarly knowledge of the Russian-Qing diplomatic relationship will be significantly upgraded. Connecting Russian studies, Qing/Chinese studies, and Eurasian studies, this study also ties material culture, political culture, and diplomatic culture together. It promotes the study of official seals and emblem symbols in worldwide diplomatic history.

Keywords: Russia-Qing diplomatic relation, Treaty of Beijing (1860), Treaty of Nerchinsk (1689), Treaty seals

Procedia PDF Downloads 207