Search results for: Construction materials

Authors: S. Assengone Otogo Be, A. Fahs, L. Belec, T. A. Nguyen Tien, G. Louarn, J-F. Chailan

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Glass fiber-reinforced composite materials have gradually developed in all sectors ranging from consumer products to aerospace applications. However, the weak point is most often the fiber/matrix interface, which can reduce the durability of the composite material. To solve this problem, it is essential to control the interphase and improve our understanding of the adhesion mechanism at the fibre/matrix interface. The interphase properties depend on the nature of the sizing applied on the surface of the glass fibers during their manufacture in order to protect them, facilitate their handling, and ensure fibre/matrix adhesion. The sizing composition, and in particular the nature of the coupling agent and the film-former affects the mechanical properties and the durability of composites. The aim of our study is, therefore, to develop and study composite materials with simplified sizing systems in order to understand how the main constituents modify the mechanical properties and the durability of composites from the nanometric to the macroscopic scale. Two model systems were elaborated: an epoxy matrix reinforced with simplified-sized glass fibres and an epoxy coating applied on glass substrates treated with the same sizings as fibres. For the sizing composition, two configurations were chosen. The first configuration possesses a chemical reactivity to link the glass and the matrix, and the second sizing contains non-reactive agents. The chemistry of the sized glass substrates and fibers was analyzed by FT-IR and XPS spectroscopies. The surface morphology was characterized by SEM and AFM microscopies. The observation of the surface samples reveals the presence of sizings which morphology depends on their chemistry. The evaluation of adhesion of coated substrates and composite materials show good interfacial properties for the reactive configuration. However, the non-reactive configuration exhibits an adhesive rupture at the interface of glass/epoxy for both systems. The interfaces and interphases between the matrix and the substrates are characterized at different scales. Correlations are made between the initial properties of the sizings and the mechanical performances of the model composites.

Keywords: adhesion, interface, interphase, materials composite, simplified sizing systems, surface properties

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Authors: Rosli Mohd Yunus, Zianor Azrina Zianon Abdin, Mohammad Dalour Hossen Beg, Ridzuan Ramli

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Recently, nanocrystalline cellulose (NCC) has gained considerable interest as a promising biomaterial due to their outstanding properties such as high surface area, high mechanical properties, hydrophilicity, biocompatibility and biodegradability. The NCC also has good stability in water which is compatible for mixing of water based polymer solution or emulsions with NCC. Oil palm empty fruit bunch (EFB) contained different amount of lignocellulosic materials such as lignin, hemicellulose and cellulose. Cellulose is the most significant materials that can be extracted from EFB as nanocrystalline cellulose (NCC). In this work the nanocrystalline cellulose were produced through acid hydrolysis together with ultrasound technique. The morphology of NCC was characterized by TEM, thermal behavior has been studied with DSC, TGA analysis. Structural properties were illustrated X-Ray diffraction as well as FTIR. The hydrogel was produced using polyvinyl alcohol (PVA) with different concentration of NCC. The hydrogel composite was characterized by swelling ratio, crosslinking density, mechanical properties and morphology.

Keywords: nanocellulose, oil palm, hydrogel, water treatment

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Authors: Dahiru Jafaru Usman

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Nigerian courts have been sanctioned by a plethora of authorities to always employ the literal rule in interpreting statutes where the language of the statute is clear and unambiguous. This cardinal rule of interpretation appears not to be employed on Shari'ah issues in Nigeria. This is more pronounced in the interpretation of the jurisdiction of the Shari'ah Court of Appeal (hereinafter the court). The paper doctrinally assesses the judicial attitude of Nigerian appellate courts towards the construction of Section 277 of the 1999 Constitution as amended and other relevant statutory enactments by the State Houses of Assembly. The paper argues that a careful examination of the wordings of the constitution on the jurisdiction of the court literally reveals the intention of the constitutional drafters empowering the National Assembly and States' House of Assemblies to add to the itemised jurisdictional areas of the court other matters not mentioned. The paper found that the appellate courts failed in their construction of the constitutional provisions to accord the words and phrases used in the establishment, jurisdiction, and quorum sections of the court their ordinary and grammatical meaning. This results in consistent limitation of the jurisdiction of the court to matters of Islamic personal law. This remains so even when Decree No. 26 of 1986 was in force suspending and amending the provisions of the 1979 Constitution deleting the word 'personal' in the suspended Nigerian Constitutions. In order not to render section 277 futile, the paper recommends that appellate courts in Nigeria should as required by rules of statutory interpretation adopt literal and ordinary grammatical meaning in interpreting constitutional provisions on the jurisdiction of the court. It is further recommended that appellate courts must interpret the provisions of the 1999 constitution in a manner not to frustrate the several decades' yearnings of the Muslims for a court that would hear all their appellate criminal and civil matters on the path of Shari'ah from the lowest court to the highest. This is a duty the Nigerian Supreme Court placed on their shoulders.

Keywords: interpretation of statutes, jurisdiction, literal rule, Nigeria, Shari'ah Court of Appeal, 1999 Constitution

Procedia PDF Downloads 193

Authors: Valeda Dent

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This study explores reading and library factors related to secondary school student academic outcomes in rural areas in Uganda. This mixed methods study utilized quantitative data collected as part of a more extensive project to explore six student factors in relation to students’ school, library, and home environments. The Kitengesa Community Library in Uganda (www.kitengesalibrary.org) served as the site for this study. The factors explored for this study include reading frequency, library use frequency, library access, overall grade average (OGA), and presence and type of reading materials in the home. Results indicated that both reading frequency and certain types of reading materials read for recreational purposes are correlated with higher OGA. Reading frequency was positively correlated with student OGA for all students.

Keywords: rural village libraries, secondary school students, reading, academic achievement

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Authors: Rahul Saraswat

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More recently, a focus is given on replacing machined stainless steel metal flow-fields with inexpensive wiremesh current collectors. The flow-fields are based on simple woven wiremesh screens of various stainless steels, which are sandwiched between a thin metal plate of the same material to create a bipolar plate/flow-field configuration for use in a stack. Major advantages of using stainless steel wire screens include the elimination of expensive raw materials as well as machining and/or other special fabrication costs. Objective of the project is to improve the performance of the passive direct methanol fuel cell without increasing the cost of the cell and to make it as compact and light as possible. From the literature survey, it was found that very little is done in this direction & the following methodology was used. 1.) The passive DMFC cell can be made more compact, lighter and less costly by changing the material used in its construction. 2.) Controlling the fuel diffusion rate through the cell improves the performance of the cell. A passive liquid feed direct methanol fuel cell ( DMFC ) was fabricated using given MEA( Membrane Electrode Assembly ) and tested for different current collector structure. Mesh current collectors of different mesh densities, along with different support structures, were used, and the performance was found to be better. Methanol concentration was also varied. Optimisation of mesh size, support structure and fuel concentration was achieved. Cost analysis was also performed hereby. From the performance analysis study of DMFC, we can conclude with the following points : Area specific resistance (ASR) of wiremesh current collectors is lower than ASR of stainless steel current collectors. Also, the power produced by wiremesh current collectors is always more than that produced by stainless steel current collectors. Low or moderate methanol concentrations should be used for better and stable DMFC performance. Wiremesh is a good substitute of stainless steel for current collector plates of passive DMFC because of lower cost( by about 27 %), flexibility and light in weight characteristics of wiremesh.

Keywords: direct methanol fuel cell, membrane electrode assembly, mesh, mesh size, methanol concentration and support structure

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Authors: A. Ouargui, N. Belouaggadia, M. Ezzine

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In Morocco, the building sector is largely responsible for the evolution of energy consumption. The control of energy in this sector remains a major issue despite the rise of renewable energies. The design of an environmentally friendly building requires mastery and knowledge of energy and bioclimatic aspects. This implies taking into consideration of all the elements making up the building and the way in which energy exchanges take place between these elements. In this context, thermal insulation seems to be an ideal starting point for reducing energy consumption and greenhouse gas emissions. In this context, thermal insulation seems to be an ideal starting point for reducing energy consumption and greenhouse gas emissions. The aim of this work is to provide some solutions to reduce energy consumption while maintaining thermal comfort in the building. The objective of our work is to present an experimental study on the characterization of local materials used in the thermal insulation of buildings. These are paper recycling stabilized with cement and clay. The thermal conductivity of these materials, which were constituted based on sand, clay, cement; water, as well as treated paper, was determined by the guarded-hot-plate method. It involves the design of two materials that will subsequently be subjected to thermal and mechanical tests to determine their thermophysical properties. The results show that the thermal conductivity decreases as well in the case of the paper-cement mixture as that of the paper-clay and seems to stabilize around 40%. Measurements of mechanical properties such as flexural strength have shown that the enrichment of the studied material with paper makes it possible to reduce the flexural strength by 20% while optimizing the conductivity.

Keywords: building, composite material, insulation, thermal conductivity, paper residue

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Authors: Stephanie Wall, Guido Wimmers

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The construction and operation of buildings greatly contribute to environmental degradation through resource and energy consumption and greenhouse gas emissions. The design of the envelope system affects the environmental impact of a building in two major ways; 1) high thermal performance and air tightness can significantly reduce the operational energy of the building and 2) the material selection for the envelope largely impacts the embodied energy of the building. Life cycle assessment (LCA) is a scientific methodology that is used to systematically analyze the environmental load of processes or products, such as buildings, over their life. The paper will discuss the results of a comparative LCA of different envelope designs and the long-term monitoring of the Wood Innovation Research Lab (WIRL); a Passive House (PH), industrial building under construction in Prince George, Canada. The WIRL has a footprint of 30m x 30m on a concrete raft slab foundation and consists of shop space as well as a portion of the building that includes a two-story office/classroom space. The lab building goes beyond what was previously thought possible in regards to energy efficiency of industrial buildings in cold climates due to their large volume to surface ratio, small floor area, and high air change rate, and will be the first PH certified industrial building in Canada. These challenges were mitigated through the envelope design which utilizes solar gains while minimizing overheating, reduces thermal bridges with thick (570mm) prefabricated truss walls filled with blown in mineral wool insulation and a concrete slab and roof insulated with EPS rigid insulation. The envelope design results in lower operational and embodied energy when compared to buildings built to local codes or with steel. The LCA conducted using Athena Impact Estimator for Buildings identifies project specific hot spots as well illustrates that for high-efficiency buildings where the operational energy is relatively low; the embodied energy of the material selection becomes a significant design decision as it greatly impacts the overall environmental footprint of the building. The results of the LCA will be reinforced by long-term monitoring of the buildings envelope performance through the installation of temperature and humidity sensors throughout the floor slab, wall and roof panels and through detailed metering of the energy consumption. The data collected from the sensors will also be used to reinforce the results of hygrothermal analysis using WUFI®, a program used to verify the durability of the wall and roof panels. The WIRL provides an opportunity to showcase the use of wood in a high performance envelope of an industrial building and to emphasize the importance of considering the embodied energy of a material in the early stages of design. The results of the LCA will be of interest to leading researchers and scientists committed to finding sustainable solutions for new construction and high-performance buildings.

Keywords: high performance envelope, life cycle assessment, long term monitoring, passive house, prefabricated panels

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Authors: Bandar Alkahlan

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The King Abdulaziz City for Science and Technology (KACST) created the Saudi Future Dwelling (SFD) initiative to identify, localize and commercialize a scalable home manufacturing technology suited to deployment across the Kingdom of Saudi Arabia (KSA). This paper outlines the journey, the creation of the international project delivery team, the product design, the selection of the process technologies, and the outcomes. A target was set to remove 85% of the construction and finishing processes from the building site as these activities could be more efficiently completed in a factory environment. Therefore, integral to the SFD initiative is the successful industrialization of the home building process using appropriate technologies, automation, robotics, and manufacturing logistics. The technologies proposed for the SFD housing system are designed to be energy efficient, economical, fit for purpose from a Saudi cultural perspective, and will minimize the use of concrete, relying mainly on locally available Saudi natural materials derived from the local resource industries. To this end, the building structure is comprised of a hybrid system of structural insulated panels (SIP), combined with a light gauge steel framework manufactured in a large format panel system. The paper traces the investigative process and steps completed by the project team during the selection process. As part of the SFD Project, a pathway was mapped out to include a proof-of-concept prototype housing module and the set-up and commissioning of a lab-factory complete with all production machinery and equipment necessary to simulate a full-scale production environment. The prototype housing module was used to validate and inform current and future product design as well as manufacturing process decisions. A description of the prototype design and manufacture is outlined along with valuable learning derived from the build and how these results were used to enhance the SFD project. The industrial engineering concepts and lab-factory detailed design and layout are described in the paper, along with the shop floor I.T. management strategy. Special attention was paid to showcase all technologies within the lab-factory as part of the engagement strategy with private investors to leverage the SFD project with large scale factories throughout the Kingdom. A detailed analysis is included in the process surrounding the design, specification, and procurement of the manufacturing machinery, equipment, and logistical manipulators required to produce the SFD housing modules. The manufacturing machinery was comprised of a combination of standardized and bespoke equipment from a wide range of international suppliers. The paper describes the selection process, pre-ordering trials and studies, and, in some cases, the requirement for additional research and development by the equipment suppliers in order to achieve the SFD objectives. A set of conclusions is drawn describing the results achieved thus far, along with a list of recommended ongoing operational tests, enhancements, research, and development aimed at achieving full-scale engagement with private sector investment and roll-out of the SFD project across the Kingdom.

Keywords: automation, dwelling, manufacturing, product design

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Authors: Song Hung Chi, Lee Chun Benn

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Follow by the “A Research on Types of Settlement Housing Alterations of Chinese New Village in Malaysia- A Study in Ampang New Village, Selangor” preliminary informed that the main factors for expansion and enlargement suitably due to the needs of user's life and restoration purpose. The alterations behavior generally derived at the rear position of main house with different types of derivatives, the averages expansion area are not exceeding of 100㎡, while building materials used were wooden, wooden structure, and zinc which are non-permanent building materials. Therefore, a subsequent studies taken in this paper, further to analyze the drawing with summarize method, to explore the derived forms and the constituted rules of housing alterations in Ampang Village, as a more complete presentation of housing alterations in New Village. Firstly, classified the existing housing alterations into three types by using summarize method, which are Type 1, Additional of Prototype House; Type 2, Expansion of Prototype House; and Type 3, Diffusion of Additional. The results shows that the derivative mode of alterations can be divided into the use of "continuous wall" or "non-continuous wall," this will affects the structural systems and roof styles of alterations, and formed the different layers of interior space with "stages" and "continuity". On the aspects of spatial distribution, sacrificial area as a prescriptive function of space, it was mostly remains in the original location which in the center of living area after alterations. It is an important characteristic in a New Village house, reflecting the traditional Ethics of Hakka Chinese communities in the settlement. In addition, wooden as the main building materials of constituted rules for the prototype house, although there were appeared other building materials, such as cement, brick, glass, metal and zinc after alterations, but still mostly as "wooden house" pattern. Result show because of the economy of village does not significantly improve, and also forming the similarity types in alterations and constructions of the additional building with the existing. It did not significantly improve on the quality of living, but only increased the area of usage space.

Keywords: Ampang new village, derived forms, constituted rules, alterations

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Authors: M. Uysal, M. Yilmaz, I. Tiryakioğlu

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Digital Terrain Model (DTM) is a digital numerical representation of the Earth's surface. DTMs have been applied to a diverse field of tasks, such as urban planning, military, glacier mapping, disaster management. In the expression of the Earth' surface as a mathematical model, an infinite number of point measurements are needed. Because of the impossibility of this case, the points at regular intervals are measured to characterize the Earth's surface and DTM of the Earth is generated. Hitherto, the classical measurement techniques and photogrammetry method have widespread use in the construction of DTM. At present, RADAR, LiDAR, and stereo satellite images are also used for the construction of DTM. In recent years, especially because of its superiorities, Airborne Light Detection and Ranging (LiDAR) has an increased use in DTM applications. A 3D point cloud is created with LiDAR technology by obtaining numerous point data. However recently, by the development in image mapping methods, the use of unmanned aerial vehicles (UAV) for photogrammetric data acquisition has increased DTM generation from image-based point cloud. The accuracy of the DTM depends on various factors such as data collection method, the distribution of elevation points, the point density, properties of the surface and interpolation methods. In this study, the random data reduction method is compared for DTMs generated from image based point cloud data. The original image based point cloud data set (100%) is reduced to a series of subsets by using random algorithm, representing the 75, 50, 25 and 5% of the original image based point cloud data set. Over the ANS campus of Afyon Kocatepe University as the test area, DTM constructed from the original image based point cloud data set is compared with DTMs interpolated from reduced data sets by Kriging interpolation method. The results show that the random data reduction method can be used to reduce the image based point cloud datasets to 50% density level while still maintaining the quality of DTM.

Keywords: DTM, Unmanned Aerial Vehicle (UAV), uniform, random, kriging

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Authors: Sonia Kudlacik-Kramarczyk, Anna Drabczyk, Dagmara Malina, Bozena Tyliszczak, Agnieszka Sobczak-Kupiec

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Introduction: In the preparation of polymer materials, compounds of natural origin are currently gaining more and more interest. This is particularly noticeable in the case of synthesis of materials considered for biomedical use. Then, selected material has to meet many requirements. It should be characterized by non-toxicity, biodegradability and biocompatibility. Therefore special attention is directed to substances such as polysaccharides, proteins or substances that are the basic building components of proteins, i.e. amino acids. These compounds may be crosslinked with other reagents that leads to the preparation of polymer matrices. Such amino acids as e.g. cysteine or histidine. On the other hand, previously mentioned requirements may be met by polymers obtained as a result of biosynthesis, e.g. polyhydroxybutyrate. This polymer belongs to the group of aliphatic polyesters that is synthesized by microorganisms (selected strain of bacteria) under specific conditions. It is possible to modify matrices based on given polymer with substances of various origin. Such a modification may result in the change of their properties or/and in providing the material with new features desirable in viewpoint of specific application. Described materials are synthesized using UV radiation. Process of photopolymerization is fast, waste-free and enables to obtain final products with favorable properties. Methodology: Polymer matrices have been prepared by means of photopolymerization. First step involved the preparation of solutions of particular reagents and mixing them in the appropriate ratio. Next, crosslinking agent and photoinitiator have been added to the reaction mixture and the whole was poured into the Petri dish and treated with UV radiation. After the synthesis, polymer samples were dried at room temperature and subjected to the numerous analyses aimed at the determining their physicochemical properties. Firstly, sorption properties of obtained polymer matrices have been determined. Next, mechanical properties have been characterized, i.e. tensile strength. The ability to deformation under applied stress of all prepared polymer matrices has been checked. Such a property is important in viewpoint of the application of analyzed materials e.g. as wound dressings. Wound dressings have to be elastic because depending on the location of the wound and its mobility, such a dressing has to adhere properly to the wound. Furthermore, considering the use of the materials for biomedical purposes it is essential to determine its behavior in environments simulating these ones occurring in human body. Therefore incubation studies using selected liquids have also been conducted. Conclusions: As a result of photopolymerization process, polymer matrices based on natural compounds have been prepared. These exhibited favorable mechanical properties and swelling ability. Moreover, biocompatibility in relation to simulated body fluids has been stated. Therefore it can be concluded that analyzed polymer matrices constitute an interesting materials that may be considered for biomedical use and may be subjected to the further more advanced analyses using specific cell lines.

Keywords: photopolymerization, polymer matrices, simulated body fluids, swelling properties

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Authors: Hassan Bohra, Mingfeng Wang

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Conjugated porous polymers (CPPs) are amorphous, insoluble and highly robust organic semiconductors that have been largely synthesized by traditional transition-metal catalyzed reactions. The distinguishing feature of CPP materials is that they combine microporosity and high surface areas with extended conjugation, making them ideal for versatile applications such as separation, catalysis and energy storage. By applying a modular approach to synthesis, chemical and electronic properties of CPPs can be tailored for specific applications making these materials economical alternatives to inorganic semiconductors. Direct arylation - an environmentally benign alternative to traditional polymerization reactions – is one such reaction that extensively over the last decade for the synthesis of linear p-conjugated polymers. In this report, we present the synthesis and characterization of a new series of robust conjugated porous polymers synthesized by facile direct arylation polymerization of thiophene-flanked acceptor building blocks with multi-brominated aryls with different geometries. We observed that the porosities and morphologies of the polymers are determined by the chemical structure of the aryl bromide used. Moreover, good control of the optical bandgap in the range 2.53 - 1.3 eV could be obtained by using different building blocks. Structure-property relationships demonstrated in this study suggest that direct arylation polymerization is an attractive synthetic tool for the rational design of porous organic materials with tunable photo-physical properties for applications in photocatalysis, energy storage and conversion.

Keywords: direct arylation, conjugated porous polymers, triazine, photocatalysis

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Authors: Ghulam Mustafa Kamal, Xiaohua Wang, Bin Yuan, Abdullah Ijaz Hussain, Jie Wang, Shahzad Ali Shahid Chatha, Xu Zhang, Maili Liu

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Organic food products are becoming increasingly popular in recent years, as consumers have turned more health conscious and environmentally aware. A lot of consumers have understood that the organic foods are healthier than conventionally produced food stuffs. Price difference between conventional and organic foods is very high. So, it is very common to cheat the consumers by mislabeling and adulteration. Our study describes the 1H NMR based approach to characterize and differentiate soy sauce prepared from organically and conventionally grown raw materials (wheat and soybean). Commercial soy sauce samples fermented from organic and conventional raw materials were purchased from local markets. Principal component analysis showed clear separation among organic and conventional soy sauce samples. Orthogonal partial least squares discriminant analysis showed a significant (p < 0.01) separation among two types of soy sauce yielding leucine, isoleucine, ethanol, glutamate, lactate, acetate, β-glucose, sucrose, choline, valine, phenylalanine and tyrosine as important metabolites contributing towards this separation. Abundance ratio of 13C to 12C was also evaluated by 1H NMR spectroscopy which showed an increased ratio of 13C isotope in organic soy sauce samples indicating the organically grown wheat and soybean used for the preparation of organic soy sauce. Results of the study can be helpful to the end users to select the soy sauce of their choice. This information could also pave the way to further trace and authenticate the raw materials used in production of soy sauce.

Keywords: 1H NMR, multivariate analysis, organic, conventional, 13C isotopic ratio, soy sauce

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Authors: Korosh Khorshidi

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Due to the increasing use of different materials, such as auxetic structures, it is necessary to investigate mechanical phenomena, such as vibration, in structures made of these types of materials. This paper examines the forced vibrations of a three-layer cylindrical shell containing inviscid fluid under shock load. All three layers are made of aluminum, and the central layer is made of a re-entrant honeycomb cell structure. Using high-order shear deformation theories (HSDT) and Hamilton’s principle, the governing equations of the system have been extracted and solved by the Galerkin weighted residual method. The outputs of the Abaqus finite element software are used to validate the results. The system is investigated with both simple and clamped support conditions. Finally, this study investigates the influence of the geometrical parameters of the shell and the auxetic structure, as well as the type, intensity, duration, and location of the load, and the effect of the fluid on the dynamic and time responses.

Keywords: force vibration, cylindrical shell, auxetic structure, inviscid fluid

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Authors: Chung-Yu Wu, Chia-Chi Chang, Wei-Ming Chen, Pu-Wei Wu, Shih-Fan Chen, Po-Chun Chen

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Electrostimulation medical devices for neural diseases require electroactive and biocompatible materials to transmit signals from electrodes to targeting tissues. Protection of surrounding tissues has become a great challenge for long-term implants. In this study, we designed back-end processes with compatible, efficient, and reliable advantages over the current state-of-the-art. We explored a hermetic packaging process with high quality of adhesion and uniformity as the biocompatible devices for long-term implantation. This approach is able to provide both excellent biocompatibility and protection to the biomedical electronic devices by performing conformal coating of biocompatible materials. We successfully developed a packaging process that is capable of exposing the stimulating electrode and cover all other faces of chip with high quality of protection to prevent leakage of devices and body fluid.

Keywords: biocompatible package, medical microelectronics, surface coating, long-term implantation

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Authors: Michal Brazda, Miroslav Urbanek, Martina Koukolikova

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This work focuses on the development of functional surfaces and edges for cutting and forming tools created through the Directed Energy Deposition (DED) technology. In the context of growing challenges in modern engineering, additive technologies, especially DED, present an innovative approach to manufacturing tools for forming and cutting. One of the key features of DED is its ability to precisely and efficiently deposit Fully dense metals from powder feedstock, enabling the creation of complex geometries and optimized designs. Gradually, it becomes an increasingly attractive choice for tool production due to its ability to achieve high precision while simultaneously minimizing waste and material costs. Tools created using DED technology gain significant durability through the utilization of high-performance materials such as nickel alloys and tool steels. For high-temperature applications, Nimonic 80A alloy is applied, while for cold applications, M2 tool steel is used. The addition of ceramic materials, such as tungsten carbide, can significantly increase the tool's resistance. The introduction of functionally graded materials is a significant contribution, opening up new possibilities for gradual changes in the mechanical properties of the tool and optimizing its performance in different sections according to specific requirements. In this work, you will find an overview of individual applications and their utilization in the industry. Microstructural analyses have been conducted, providing detailed insights into the structure of individual components alongside examinations of the mechanical properties and tool life. These analyses offer a deeper understanding of the efficiency and reliability of the created tools, which is a key element for successful development in the field of cutting and forming tools. The production of functional surfaces and edges using DED technology can result in financial savings, as the entire tool doesn't have to be manufactured from expensive special alloys. The tool can be made from common steel, onto which a functional surface from special materials can be applied. Additionally, it allows for tool repairs after wear and tear, eliminating the need for producing a new part and contributing to an overall cost while reducing the environmental footprint. Overall, the combination of DED technology, functionally graded materials, and verified technologies collectively set a new standard for innovative and efficient development of cutting and forming tools in the modern industrial environment.

Keywords: additive manufacturing, directed energy deposition, DED, laser, cutting tools, forming tools, steel, nickel alloy

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Authors: T. S. Sidhu

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Amongst the existing coatings methods, the cold spray is new upcoming process to deposit coatings. As from the name itself, the cold spray coating takes place at very low temperature as compare to other thermal spray coatings. In all other thermal spray coating process the partial melting of the coating powder particles takes place before deposition, but cold spray process takes place in solid state. In cold spray process, the bonding of coating power with substrate is not metallurgical as in other thermal spray processes. Due to supersonic speed and less temperature of spray particles, solid state, dense, and oxide free coatings are produced. Due to these characteristics, the cold spray coatings have been used to protect the materials against hot corrosion. In the present study, the cold spray process, cold spray fundaments, its types, and its applications for high temperatures are discussed in the light of presently available literature. In addition, the assessment of cold spray with the competitive technologies has been conferred with available literature.

Keywords: cold spray coating, hot corrosion, thermal spray coating, high-temperature materials

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Authors: Roman Medvedev, Andrey Yakshin, Konstantin Nikolaev, Sergey Yakunin, Fred Bijkerk

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Multilayer structures are used as spectroscopic elements in fluorescence analysis. These serve the purpose of analyzing soft x-ray emission spectra of materials upon excitation by x-rays or electrons. The analysis then allows quantitative determination of the x-ray emitting elements in the materials. Shorter wavelength range for this application, below 2.5nm, can be covered by using short period multilayers, with a period of 2.5 nm and lower. Thus the detrimental effect on the reflectivity of morphological roughness between materials of the multilayers becomes increasingly pronounced. Ion beam polishing was previously shown to be effective in reducing roughness in some multilayer systems with Si. In this work, we explored W/Si multilayers with the period of 2.5 nm. Si layers were polishing by Ar ions, employing low energy ions, 100 and 80 eV, with the etched Si thickness being in the range 0.1 to 0.5 nm. CuK X-ray diffuse scattering measurements revealed a significant reduction in the diffused scattering in the polished multilayers. However, Grazing Incidence CuK X-ray showed only a marginal reduction of the overall roughness of the systems. Still, measurements of the structures with Grazing Incidence Small Angle X-ray scattering indicated that the vertical correlation length of roughness was strongly reduced in the polished multilayers. These results together suggest that polishing results in the reduction of the vertical propagation of roughness from layer to layer, while only slightly affecting the overall roughness. This phenomenon can be explained by ion-induced surface roughening inherently present in the ion polishing methods. Alternatively, ion-induced densification of thin Si films should also be considered. Finally, the reflectivity of 40% at 0.84 nm at grazing incidence of 9 degrees has been obtained in this work for W/Si multilayers. Analysis of the obtained results is expected to lead to further progress in reflectance.

Keywords: interface roughness, ion polishing, multilayer structures, W/Si

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Authors: Hagar Ezzat, Mostafa Attia, Ahmed Bedeir, Abdelrazek Elnagger, Matija Strlic

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Ethnographic Museum in Cairo- Egypt is a place of valuable collections (manuscripts, paintings, textiles and other ethnographic materials), the museum experiences serious neglecting with unacceptable display and storage conditions, the museum is located in Tahrir sq., which consider a high traffic area where pollution levels exceed the acceptable levels in museums. The materials used in manufacturing the display cases are expected to be source of many pollutants which affecting the sensitive oil paintings objects in the galleries. 24 diffusion tubes (12 No2, So2 & 12 O3) have been used in "winter 2014 and spring 2014" for monitoring museum environment with three cases "outdoor & indoor and in the gallery display". A series of analytical techniques with scientific tools: Ion Chromatography have been used to assess measurements and effects of gas pollutants on the museum which help us to make good assessment for the damage of oil paintings objects and the condition of the museum and understand the effect of the museum environment on the deterioration of the sensitive oil paintings.

Keywords: environment, museum, paintings, ethnographic, conservation

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Authors: Ngo the Bach

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Vietnam is one of not many Asian countries that have a long-standing and famous tradition of pottery production. Vietnam is also one of three countries including China, Vietnam, and Japan developed strongly the export of ceramics to other countries. In recent decades, the studies of Vietnamese and foreign scholars on Vietnamese trade ceramics as well as Vietnamese foreign trade was initially recorded. The aim of this article is to introduce an overview of the findings situation and research results; the development of Vietnam ceramics and the Vietnamese history of maritime trade with Asian ceramics from the 14th century to the 17th century. Given that, the author systematized materials; carried out the synthetic and analysis for research results of Vietnamese and foreign researchers until now on Vietnamese export ceramics on the basis of the historical sources, archaeological findings discovered from relics in the tombs, relics of residence, relics of trading port inland, and the ancient shipwreck sank in the Asian countries.

Keywords: Vietnamese ceramics, trading, maritime, international

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Authors: Tatiana Tunon, Gottfried Pestal

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Government agencies responsible for the management of fisheries resources publish many types of grey literature, and these materials are increasingly accessible to the public on agency websites. However, scope and quality vary considerably, and end-users need meta-data about the report series when deciding whether to use the information (e.g. apply the methods, include the results in a systematic review), or when prioritizing materials for archiving (e.g. library holdings, reference databases). A proposed taxonomy for these report series was developed based on a review of 41 report series from 6 government agencies in 4 countries (Canada, New Zealand, Scotland, and United States). Each report series was categorized according to multiple criteria describing peer-review process, content, and purpose. A robust classification tree was then fitted to these descriptions, and the resulting taxonomic groups were used to compare agency output from 4 countries using reports available in their online repositories.

Keywords: classification tree, fisheries, government, grey literature

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Authors: Khaoula Hidouri, Ali Benhmidene, Bechir Chouachi, Dhananjay R. Mishra, Ammar Houas

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Activated carbon DSAC36-24 iy is adsorbent materials, characterized by a specific surface area of 548.13 m²g⁻¹. Their manufacture uses the natural raw materials like the nucleus of dates. In this study the treatment is done in two stages: A chemical treatment by H₃PO₄ followed by a physical treatment under nitrogen for 1 hour then under stream of CO₂ for 24 hours. A characterization of the various parameters was determined such as the measurement of the specific surface area, determination of pHPZC, bulk density, iodine value. The study of the adsorption of organic molecules (hydroquinone, paranitrophenol, 2,4-dinitrophenol, 2,4,6-trinitrophenol) indicates that the adsorption phenomena are essentially due to the van der Waals interaction. In the case of organic molecules carrying the polar substituents, the existence of hydrogen bonds is also proved by the donor-acceptor forces. The study of the pH effect was done with modeling by different models (Langmuir, Freundlich, Langmuir-Freundlich, Redlich-Peterson), a kinetic treatment is also followed by the application of Lagergren, Weber, Macky.

Keywords: adsoprtion ishoterms, adsorption kinetics, DSAC36-24, organic molecule

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Authors: A. Kebbeb, M. Mostefai, F. Benmerzoug, Y. Chahir

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The multimodal biometric identification is the combination of several biometric systems. The challenge of this combination is to reduce some limitations of systems based on a single modality while significantly improving performance. In this paper, we propose a new approach to the construction and the protection of a multimodal biometric database dedicated to an identification system. We use a topological watermarking to hide the relation between face image and the registered descriptors extracted from other modalities of the same person for more secure user identification.

Keywords: biometric databases, multimodal biometrics, security authentication, digital watermarking

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Authors: Alper Tolga Kumtepe, Erdem Erdogdu, M. Recep Okur, Eda Kaypak, Ozlem Kaya, Serap Ugur, Deniz Dincer, Hakan Yildirim

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Interaction is one of the most important components of open and distance learning. According to Moore, who proposed one of the keystones on interaction types, there are three basic types of interaction: learner-teacher, learner-content, and learner-learner. From these interaction types, learner-content interaction, without doubt, can be identified as the most fundamental one on which all education is based. Efficacy, efficiency, and attraction of open and distance learning systems can be achieved by the practice of effective learner-content interaction. With the development of new technologies, interactive e-learning materials have been commonly used as a resource in open and distance learning, along with the printed books. The intellectual engagement of the learners with the content that is course materials may also affect their satisfaction for the open and distance learning practices in general. Learner satisfaction holds an important place in open and distance learning since it will eventually contribute to the achievement of learning outcomes. Using the learner-content interaction activities in course materials, Anadolu University, by its Open Education system, tries to involve learners in deep and meaningful learning practices. Especially, during the e-learning material design and production processes, identifying appropriate learner-content interaction activities within the context of learning outcomes holds a big importance. Considering the lack of studies adopting this approach, as well as its being a study on the use of e-learning materials in Open Education system, this research holds a big value in open and distance learning literature. In this respect, the present study aimed to investigate a) which learner-content interaction activities included in interactive courses are the most effective in learners’ achievement of verbal information learning outcomes and b) to what extent distance learners are satisfied with these learner-content interaction activities. For this study, the quasi-experimental research design was adopted. The 120 participants of the study were from Anadolu University Open Education Faculty students living in Eskişehir. The students were divided into 6 groups randomly. While 5 of these groups received different learner-content interaction activities as a part of the experiment, the other group served as the control group. The data were collected mainly through two instruments: pre-test and post-test. In addition to those tests, learners’ perceived learning was assessed with an item at the end of the program. The data collected from pre-test and post-test were analyzed by ANOVA, and in the light of the findings of this approximately 24-month study, suggestions for the further design of e-learning materials within the context of learner-content interaction activities will be provided at the conference. The current study is planned to be an antecedent for the following studies that will examine the effects of activities on other learning domains.

Keywords: interaction, distance education, interactivity, online courses

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Authors: Amy Williamson, Kerry Armstrong, Jason Edwards, Patricia Obst

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Australian national policy endorses a responsive approach to work health and safety (WHS) regulation, combining positive motivators (education and guidance), with compliance monitoring and enforcement to encourage and secure compliance with legislation. Despite theoretical support for responsive regulation, there is limited evidence regarding how to achieve best results in practice. Using positive psychology as a novel paradigm, this study aims to investigate how non-punitive regulatory interactions can be improved to further encourage regulatory compliance in the construction industry. As part of a larger project, semi-structured interviews were conducted with 35 inspectorate staff and 11 managers in the Australian (Queensland) construction industry. Using an inductive, grounded approach, an in-depth qualitative investigation was conducted to identify the positive psychological principles which underpin effective use of the non-punitive aspects of responsive regulation. Results highlighted the importance of effective engagement between inspectors and industry managers. This involved the need to interact cooperatively and encourage compliance with WHS legislation. Several strategies were identified that assisted regulatory interactions and the ability of inspectors to engage. The importance of communication and interpersonal skills was reported to be critical to any interaction, regardless of the nature of the visit and regulatory tools used. In particular, the use of clear and open communication fostered trust and rapport which facilitated more positive interactions. The importance of respect and empathy was also highlighted. The need for provision of guidance and direction on how to achieve compliance was also reported. This related to ensuring companies understand their WHS obligations, providing specific advice regarding how to rectify a breach and meet compliance requirements, and ensuring sufficient follow up to confirm that compliance is successfully achieved. In the absence of imminent risk, allowing companies the opportunity to comply before further action is taken was also highlighted. Increased proactive engagement with industry to educate and promote the vision of safety at work was also reported. Finally, provision of praise and positive feedback was reported to assist interactions and encourage the continuation of good practices. Evidence from positive psychology and organisational psychology was obtained to support the use of each strategy in practice. In particular, the area of positive leadership provided a useful framework to consider the factors and conditions that drive positive interactions within the context of work health and safety and the specific relationship between inspectors and industry managers. This study provides fresh insight into key psychological principles which support non-punitive regulatory interactions in the area of workplace health and safety. The findings of this research contribute to a better understanding of how inspectors can enhance the efficacy of their regulatory interactions to improve compliance with legislation. Encouraging and assisting compliance through effective non-punitive activity offers a sustainable pathway for promoting safety and preventing fatalities and injuries in the construction industry.

Keywords: engagement, non-punitive approaches to compliance, positive interactions in the workplace, work health and safety compliance

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Authors: H. Aksas, H. Babaci, K. Louhab

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In this paper, a comparative study of the adsorption of Chromium and dyes, onto mixture biosorbents, olive stones and date pits at different percentage was investigated in aqueous solution. The study of various parameters: Effect of contact time, pH, temperature and initial concentration shows that these materials possess a high affinity for the adsorption of chromium for the adsorption of dye bezaktiv yellow HE-4G. To deepen the comparative study of the adsorption of chromium and dye with the use of different blends of olive stones and date pits, the following models are studied: Langmuir, Freundlich isotherms and Dubinin- Radushkvich (D-R) were used as the adsorption equilibrium data model. Langmuir isotherm model was the most suitable for the adsorption of the dye bezaktiv HE-4G and the D-R model is most suitable for adsorption Chrome. The pseudo-first-order model, pseudo-second order and intraparticle diffusion were used to describe the adsorption kinetics. The apparent activation energy was found to be less than 8KJ/mol, which is characteristic of a controlled chemical reaction for the adsorption of two materials. t was noticed that adsorption of chromium and dye BEZAKTIV HE-YELLOW 4G follows the kinetics of the pseudo second order. The study of the effect of temperature was quantified by calculating various thermodynamic parameters such as Gibbs free energy, enthalpy and entropy changes. The resulting thermodynamic parameters indicate the endothermic nature of the adsorption of Cr (VI) ions and the dye Bezaktiv HE-4G. But these materials are very good adsorbents, as they represent a low cost. in addition, it has been noticed that the greater the quantity of olive stone in the mixture increases, the adsorption ability of the dye or chromium increases.

Keywords: chromium ions, anions dye, sorption, mixed adsorbents, olive stone, date pits

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Authors: Yuchao Hua, Lingai Luo

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Thermal energy storage is of critical importance for the highly-efficient utilization of renewable energy sources. Over the past decades, single-tank thermocline technology has attracted much attention owing to its high cost-effectiveness. In the present work, we investigate the influence of the filler porosity’s non-uniform distribution on the thermal performance of the packed-bed sensible heat thermocline storage tanks on the basis of the analytical model obtained by the Laplace transform. It is found that when the total amount of filler materials (i.e., the integration of porosity) is fixed, the different porosity distributions can result in the significantly-different behaviors of outlet temperature and thus the varied charging and discharging efficiencies. Our results indicate that a non-uniform distribution of the fillers with the proper design can improve the heat storage performance without changing the total amount of the filling materials.

Keywords: energy storage, heat thermocline storage tank, packed bed, transient thermal analysis

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Authors: Doaa H. Elgohary, Dina M. Hamoda, S. Yahia

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Technical textiles refer to textile materials that are engineered and designed to have specific functionalities and performance characteristics beyond their traditional use as apparel or upholstery fabrics. These textiles are usually developed for their unique properties such as strength, durability, flame retardancy, chemical resistance, waterproofing, insulation and other special properties. The development and use of technical textiles are constantly evolving, driven by advances in materials science, manufacturing technologies and the demand for innovative solutions in various industries. Kevlar 29 is a type of aramid fiber developed by DuPont. It is a high-performance material known for its exceptional strength and resistance to impact, abrasion, and heat. Kevlar 29 belongs to the Kevlar family, which includes different types of aramid fibers. Kevlar 29 is primarily used in applications that require strength and durability, such as ballistic protection, body armor, and body armor for military and law enforcement personnel. It is also used in the aerospace and automotive industries to reinforce composite materials, as well as in various industrial applications. Two different Kevlar samples were used coated with cooper lithium silicate (CLS); ten different mechanical and physical properties (weight, thickness, tensile strength, elongation, stiffness, air permeability, puncture resistance, thermal conductivity, stiffness, and spray test) were conducted to approve its functional performance efficiency. The influence of different mechanical properties was statistically analyzed using an independent t-test with a significant difference at P-value = 0.05. The radar plot was calculated and evaluated to determine the best-performing samples. The results of the independent t-test observed that all variables were significantly affected by yarn counts except water permeability, which has no significant effect. All properties were evaluated for samples 1 and 2, a radar chart was used to determine the best attitude for samples. The radar chart area was calculated, which shows that sample 1 recorded the best performance, followed by sample 2. The surface morphology of all samples and the coating materials was determined using a scanning electron microscope (SEM), also Fourier Transform Infrared Spectroscopy Measurement for the two samples.

Keywords: cooper lithium silicate, independent t-test, kevlar, technical textiles.

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Authors: Parnian Kianfar, Navid Zarif Karimi, Giangiacomo Minak

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Drilling is one of the most important machining operations as numerous holes must be drilled in order to install mechanical fasteners for assembly in composite structures. Delamination is a major problem associated with the drilling of fiber reinforced composite materials, which degrades the mechanical properties of these materials. In drilling, delamination is initiated when the drilling force exceeds a threshold value, particularly at the critical entry and exit locations of the drill bit. The chisel edge of twist drill is a major contributor to the thrust force which is the primary cause of delamination. The main objective of this paper is to study the effect of chisel edge and pilot hole on thrust force and delamination during drilling of glass fiber reinforced composites. For this purpose, two sets of experiments, with and without pilot hole, were conducted with different drilling conditions. The results show a great reduction in the thrust force when a pilot hole is present which removes the chisel edge contribution.

Keywords: composites, chisel edge, drilling, delamination

Procedia PDF Downloads 443

Authors: Ntachobazi bosco

Abstract:

Tourism Development and Planning in Rwanda: Rwanda, a small landlocked country located in the heart of Africa, has experienced significant growth in its tourism industry in recent years. The country’s stunning natural beauty, rich cultural heritage, and warm hospitality have made it an attractive destination for travelers from around the world. However, to ensure sustainable tourism development and planning, the Rwandan government has implemented various strategies and policies to promote responsible tourism practices. Infrastructure Development: To support the growth of the tourism industry, the Rwandan government has invested heavily in infrastructure development. This includes the construction of new hotels, resorts, and lodges, as well as the upgrading of existing facilities. The government has also improved the country’s transportation network, including the construction of new airports and the upgrading of existing ones. Conservation Efforts: Rwanda is home to several national parks and reserves, including the famous Volcanoes National Park, which is known for its mountain gorilla populations. To protect these natural wonders, the Rwandan government has implemented conservation efforts, such as the establishment of protected areas and the development of sustainable tourism practices. Community-Based Tourism: Community-based tourism is a key component of Rwanda’s tourism development strategy. The government has established several community-based tourism programs, which aim to involve local communities in the tourism industry and provide them with economic benefits. These programs include homestays, village tours, and cultural performances. Sustainable Tourism Practices: To promote sustainable tourism practices, the Rwandan government has implemented several initiatives, such as the use of eco-friendly accommodations and the promotion of responsible wildlife viewing practices. The government has also established the Rwanda Tourism Board, which is responsible for promoting and regulating the tourism industry. Challenges and Opportunities: Despite the growth of the tourism industry in Rwanda, several challenges need to be addressed, such as the lack of skilled labor and the need for more infrastructure development. However, there are also several opportunities for the industry, such as the potential for ecotourism and the growth of the meetings, incentives, conventions, and exhibitions (MICE) market.

Keywords: tourism, in rwanda, developent, in africa

Procedia PDF Downloads 68