Search results for: historical structures

Authors: Mauro Iannazzone, Carmine D'Agostino

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Off-shore wind turbines are currently considered as a reliable source of renewable energy Worldwide and especially in the UK. Most of the operational off-shore wind turbines located in shallow waters (i.e. < 30 m) are supported on monopiles. Monopiles are open-ended steel tubes with diameter ranging between 4 to 6 m. It is expected that future off-shore wind farms will be located in water depths as high as 70 m. Therefore, alternative foundation arrangements are needed. Foundations for off-shore structures normally consist of open-ended piles driven into the soil by means of impact hammers. During pile installation, the soil inside the pile may be mobilized by the increasing shear strength such as to prevent more soil from entering the pile. This phenomenon is known as soil plugging, and represents an important issue as it may change significantly the driving resistance of open-ended piles. In fact, if the plugging formation is unexpected, the installation may require more powerful and more expensive hammers. Engineers need to estimate whether the driven pile will be installed in a plugged or unplugged mode. As a consequence, a prediction of the degree of soil plugging is required in order to correctly predict the drivability of the pile. This work presents a brief review of the state-of-the-art of pile driving and approaches used to predict formation of soil plugs. In addition, a novel analytical approach is proposed, which is based on the vertical equilibrium of a plugged pile. Differently from previous studies, this research takes into account the enhancement of the stress within the soil plug. Finally, the work presents and discusses a series of experimental tests, which are carried out on small-scale models piles to validate the analytical solution.

Keywords: off-shore wind turbines, pile installation, soil plugging, wind energy

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Authors: Bouanati Sidi Mohammed, N. E. Chabane Sari, Mostefa Kara Selma

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It is well-known that Organic light emitting diodes (OLEDs) are attracting great interest in the display technology industry due to their many advantages, such as low price of manufacturing, large-area of electroluminescent display, various colors of emission included white light. Recently, there has been much progress in understanding the device physics of OLEDs and their basic operating principles. In OLEDs, Light emitting is the result of the recombination of electron and hole in light emitting layer, which are injected from cathode and anode. For improve luminescence efficiency, it is needed that hole and electron pairs exist affluently and equally and recombine swiftly in the emitting layer. The aim of this paper is to modeling polymer LED and OLED made with small molecules for studying the electrical and optical characteristics. The first simulation structures used in this paper is a mono layer device; typically consisting of the poly (2-methoxy-5(2’-ethyl) hexoxy-phenylenevinylene) (MEH-PPV) polymer sandwiched between an anode usually an indium tin oxide (ITO) substrate, and a cathode, such as Al. In the second structure we replace MEH-PPV by tris (8-hydroxyquinolinato) aluminum (Alq3). We choose MEH-PPV because of it's solubility in common organic solvents, in conjunction with a low operating voltage for light emission and relatively high conversion efficiency and Alq3 because it is one of the most important host materials used in OLEDs. In this simulation, the Poole-Frenkel- like mobility model and the Langevin bimolecular recombination model have been used as the transport and recombination mechanism. These models are enabled in ATLAS -SILVACO software. The influence of doping and thickness on I(V) characteristics and luminescence, are reported.

Keywords: organic light emitting diode, polymer lignt emitting diode, organic materials, hexoxy-phenylenevinylene

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Authors: David C. Ni

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Contemporary models for N-body systems are based on temporal, two-body, and mass point representation of Newtonian mechanics. Other mainstream models include 2D and 3D Ising models based on local neighborhood the lattice structures. In Quantum mechanics, the theories of collective modes are for superconductivity and for the long-range quantum entanglement. However, these models are still mainly for the specific phenomena with a set of designated parameters. We are therefore motivated to develop a new construction directly from the complex-variable N-body systems based on the extended Blaschke functions (EBF), which represent a non-temporal and nonlinear extension of Lorentz transformation on the complex plane – the normalized momentum spaces. A point on the complex plane represents a normalized state of particle momentums observed from a reference frame in the theory of special relativity. There are only two key parameters, normalized momentum and nonlinearity for modelling. An algorithm similar to Jenkins-Traub method is adopted for solving EBF iteratively. Through iteration, the solution sets show a form of σ + i [-t, t], where σ and t are the real numbers, and the [-t, t] shows various distributions, such as 1-peak, 2-peak, and 3-peak etc. distributions and some of them are analog to the canonical distributions. The results of the numerical analysis demonstrate continuum-to-discreteness transitions, evolutional invariance of distributions, phase transitions with conjugate symmetry, etc., which manifest the construction as a potential candidate for the unification of statistics. We hereby classify the observed distributions on the finite convergent domains. Continuous and discrete distributions both exist and are predictable for given partitions in different regions of parameter-pair. We further compare these distributions with canonical distributions and address the impacts on the existing applications.

Keywords: blaschke, lorentz transformation, complex variables, continuous, discrete, canonical, classification

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Authors: Giovana Privatte Maciera, Jair Izaías Kappann

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Introduction: The violence against woman is a complex phenomenon that accompanies the woman throughout her life and is a result of a social, cultural, political and religious construction, based on the differences among the genders. Those differences are felt, mainly, because of the patriarchal system that is still present which just naturalize and legitimate the asymmetry of power. As consequence of the women’s lasting historical and collective effort for a legislation against the impunity of violence against women in the national scenery, it was ordained, in 2006, a law known as Maria da Penha. The law was created as a protective measure for women that were victims of violence and consequently for the punishment of the aggressor. Methodology: Analysis of police inquiries is established by the Police Station of Defense of the Woman of Assis city, by formal authorization of the justice, in the period of 2013 to 2015. For the evaluating of the results will be used the content analysis and the theoretical referential of Psychoanalysis. Results and Discussion: The final analysis of the inquiries demonstrated that the violence against women is reproduced by the society and the aggressor, in most cases it is a member of their own family, mainly the current or former-spouse. The most common kinds of aggression were: the threat bodily harm, and the physical violence, that normally happens accompanied by psychological violence, being the most painful for the victims. The biggest part of the aggressors was white, older than the victim, worker and had primary school. But, unlike the expected, the minority of the aggressors were users of alcohol and/or drugs and possessed children in common with the victim. There is a contrast among the number of victims who already admitted have suffered some type of violence earlier by the same aggressor and the number of victims who has registered the occurrence before. The aggressors often use the discourse of denial in their testimony or try to justify their act like the blame was of the victim. It is believed in the interaction of several factors that can influence the aggressor to commit the abuse, including psychological, personal and sociocultural factors. One hypothesis is that the aggressor has a violence history in the family origin. After the aggressor being judged, condemned or not, usually there is no rehabilitation plan or supervision that enable his change. Conclusions: It has noticed the importance of studying the aggressor’s characteristics and the reasons that took him to commit such violence, making possible the implementation of an appropriate treatment to prevent and reduce the aggressions, as well the creation of programs and actions that enable communication and understanding concerning the theme. This is because the recurrence is still high, since the punitive system is not enough and the law is still ineffective and inefficient in certain aspects and in its own functioning. It is perceived a compulsion in repeat so much for the victims as for the aggressors, because they end involving, almost always, in disturbed and violent relationships, with the relation of subordination-dominance as characteristic.

Keywords: aggressors' profile, gender equality, Maria da Penha law, violence against women

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Authors: Tuba Sari

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One of the major transformations caused by the industrial revolution, technological developments and globalization is undoubtedly acceleration of urbanization process. Globalization, in particular, is one of the major factors that trigger this transformation. In this context, as a result of the global metropolitan city system, multifunctional rising structure forms are becoming undeniable fact of the world’s leading metropolises as the manifestation of prestige and power with different life choices, easy accessibility to services related to the era of technology. The scope of research deals with five different urban centers in İstanbul where high-rise housing is increasing dramatically after 2000’s. Therefore, the research regards multi-centered urban residential pattern being created by high-rise housing structures in the city. The methodology of the research is based on two main issue, one of them is related to sampling method of high-rise housing projects in İstanbul, while the other method of the research is based on the model of Semantics. In the framework of research hypothesis, it is aimed to prove that the character of vertical intensive structuring in Istanbul is based on seeking of different forms and images in the expressive quality, considering the production of existing high-rise buildings in residential areas in recent years. In respect to rising discourse of 'World City' in the globalizing world, it is very important to state the place of Istanbul in other developing world metropolises. In the perspective of 'World City' discourse, Istanbul has different projects concerning with globalization, international finance companies, cultural activities, mega projects, etc. In brief, the aim of this research is examining transformation forms of high-rise housing development in Istanbul within the frame of developing world cities, searching and analyzing discourse and image related to these projects.

Keywords: globalization, high-rise, housing, image

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Authors: Hanlei Yang

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As a kind of popular culture in modern China, advice book on intimate relationship is turning into an important and controversial site with conflicts among neoliberalism, authoritative socialism, market-oriented principles, the science of successful sex and relationship, cosmopolitan notions of nuclear families, and the revitalization of Confucian conservatism and patriarchy. Accelerated modernization and marketization has contributed to great changes in China’s culture and social relations, which accordingly reconceptualizes and reconstructs family structures and moral ethics, particularly urban middle-class nuclear families. To comprehend the meaning of advice book fad in moral and social order, this research proposes to (i) understand the implication of Ayawawa through discourse analysis and how she mobilizes rhetorical devices and cultural resources to present a persuasive and scientific method of managing intimate relationship, (ii) examine the critical role of neoliberalism, post-feminism, and Confucian patriarchy assumed by Ayawawa in her books, (iii) explore how Ayawawa and her fans engage in establishing a model of intimate relationship and sexual subjectivity ordered by neoliberalism, class identity and authoritative socialism. Finally, this research argues that such new fad of a cultural phenomenon is gradually completed in the process of cooperation and negotiation of the state, commercial institutions, and intellectual elite agents. It helps to further learn about (i) the routine life under the influence of neoliberalism and modern hegemony, (ii) the perplexing relationship between China's indigenous cultural forms, global socio-economic and cultural influences in the late modern era.

Keywords: cultural study, intimate relationship, culture sociology, gender study

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Authors: Michał Lidner, Zbigniew SzcześNiak

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The ability to estimate blast load overpressure properly plays an important role in safety design of buildings. The issue of studying of blast loading on structural elements has been explored for many years. However, in many literature reports shock wave overpressure is estimated with simplified triangular or exponential distribution in time. This indicates some errors when comparing real and numerical reaction of elements. Nonetheless, it is possible to further improve setting similar to the real blast load overpressure function versus time. The paper presents a method of numerical analysis of the phenomenon of the air shock wave propagation. It uses Finite Volume Method and takes into account energy losses due to a heat transfer with respect to an adiabatic process rule. A system of three equations (conservation of mass, momentum and energy) describes the flow of a volume of gaseous medium in the area remote from building compartments, which can inhibit the movement of gas. For validation three cases of a shock wave flow were analyzed: a free field explosion, an explosion inside a steel insusceptible tube (the 1D case) and an explosion inside insusceptible cube (the 3D case). The results of numerical analysis were compared with the literature reports. Values of impulse, pressure, and its duration were studied. Finally, an overall good convergence of numerical results with experiments was achieved. Also the most important parameters were well reflected. Additionally analyses of dynamic response of one of considered structural element were made.

Keywords: adiabatic process, air shock wave, explosive, finite volume method

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Authors: Gergely Horvath

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The study analyzes the special provisions of the highest level of national agricultural legislation in the Fundamental Law of Hungary (25 April 2011) with descriptive, analytic and comparative methods. The agriculturally relevant articles of the constitution are very important, because –in spite of their high level of abstraction– they can determine and serve the practice comprehensively and effectively. That is why the objective of the research is to interpret the concrete sentences and phrases in connection with agriculture compared with the methods of some other relevant constitutions (historical-grammatical interpretation). The major findings of the study focus on searching for the appropriate provisions and approach capable of solving the problems of sustainable food production. The real challenge agricultural law must face with in the future is protecting or conserving its background and subjects: the environment, the ecosystem services and all the 'roots' of food production. In effect, agricultural law is the legal aspect of the production of 'our daily bread' from farm to table. However, it also must guarantee the safe daily food for our children and for all our descendants. In connection with sustainability, this unique, value-oriented constitution of an agrarian country even deals with uncustomary questions in this level of legislation like GMOs (by banning the production of genetically modified crops). The starting point is that the principle of public good (principium boni communis) must be the leading notion of the norm, which is an idea partly outside the law. The public interest is reflected by the agricultural law mainly in the concept of public health (in connection with food security) and the security of supply with healthy food. The construed Article P claims the general protection of our natural resources as a requirement. The enumeration of the specific natural resources 'which all form part of the common national heritage' also means the conservation of the grounds of sustainable agriculture. The reference of the arable land represents the subfield of law of the protection of land (and soil conservation), that of the water resources represents the subfield of water protection, the reference of forests and the biological diversity visualize the specialty of nature conservation, which is an essential support for agrobiodiversity. The mentioned protected objects constituting the nation's common heritage metonymically melt with their protective regimes, strengthening them and forming constitutional references of law. This regimes also mean the protection of the natural foundations of the life of the living and also the future generations, in the name of intra- and intergenerational equity.

Keywords: agricultural law, constitutional values, natural resources, sustainability

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Authors: Arfaoui Emna, Nouira Mariem

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Background and aims: Breastfeeding is the reference feeding for a child, especially during the first months of life. It is not widespread in many countries due to many factors. There has been a decline in exclusive breastfeeding (EB) practice, particularly in the middle- and low-income countries, i.e., Tunisia. The aim of our study was to describe the knowledge, attitudes, and practice of a sample of Tunisian mothers toward breastfeeding. Methods: It was a descriptive cross-sectional study conducted during the year 2022 over a period of two months in three health structures in the north of Tunisia among mothers of infants aged 2 to 18 months. Levels of mothers’ knowledge (low/moderate/high) were determined using a score ranging from 0 to 11 points. EB was defined as the proportion of infants who were exclusively breastfed during the first six months of life. Results: A total of 180 women with a mean age of 33±4.9 years were included. The average knowledge score was equal to 6.4 ±1.5 points, with extremes ranging from 3 to 11 points. Most of the respondents had a moderate knowledge level (44.4%). More than half of surveyed mothers (66.1%) thought that breastfeeding deforms breasts, and 16.7% thought that breastfeeding is specific to women who do not work. Breastfeeding experience during the first week of life was considered difficult in 70% of cases. The prevalence of EB up to 6 months of age was equal to 16.4% [10.8-23.2]. The main reported obstacles during breastfeeding practice were having an insufficient quantity of breast milk (18.3%) and child difficulties with sucking (12.8%), and having pain in the breast while breastfeeding (12.80%). Conclusion: Our results highlighted the insufficient level of knowledge and a low prevalence of EB in our study population. Improving mothers’ knowledge and promoting EB practice is needed. Implementing health education strategies involving healthcare workers, who represent a main actor in education and breastfeeding promotion, is very important to reach a satisfactory frequency for EB.

Keywords: breastfeeding, practices, knowledge, Tunisia

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Authors: J. N. Nackler, K. Saleh Pascha, W. Winter

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WHISCERS™ (Whole House In-Situ Carbon and Energy Reduction Solution) is an innovative process for Internal Wall Insulation (IWI) for energy-efficient retrofitting of heritage building, which uses laser measuring to determine the dimensions of a room, off-site insulation board cutting and rapid installation to complete the process. As part of a multinational investigation consortium the Austrian part adapted the WHISCERS system to local conditions of Vienna where most historical buildings have valuable stucco facades, precluding the application of an external insulation. The Austrian project contribution addresses the replacement of commonly used extruded polystyrene foam (XPS) with renewable materials such as wood and wood products to develop a more sustainable IWI system. As the timber industry is a major industry in Austria, a new innovative and more sustainable IWI solution could also open up new markets. The first approach of investigation was the Life Cycle Assessment (LCA) to define the performance of wood fibre board as insulation material in comparison to normally used XPS-boards. As one of the results the global-warming potential (GWP) of wood-fibre-board is 15 times less the equivalent to carbon dioxide while in the case of XPS it´s 72 times more. The hygrothermal simulation program WUFI was used to evaluate and simulate heat and moisture transport in multi-layer building components of the developed IWI solution. The results of the simulations prove in examined boundary conditions of selected representative brickwork constructions to be functional and usable without risk regarding vapour diffusion and liquid transport in proposed IWI. In a further stage three different solutions were developed and tested (1 - glued/mortared, 2 - with soft board, connected to wall with gypsum board as top layer, 3 - with soft board and clay board as top layer). All three solutions presents a flexible insulation layer out of wood fibre towards the existing wall, thus compensating irregularities of the wall surface. From first considerations at the beginning of the development phase, three different systems had been developed and optimized according to assembly technology and tested as small specimen in real object conditions. The built prototypes are monitored to detect performance and building physics problems and to validate the results of the computer simulation model. This paper illustrates the development and application of the Internal Wall Insulation system.

Keywords: internal insulation, wood fibre, hygrothermal simulations, monitoring, clay, condensate

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Authors: Rony Tawk, Boutros Ghannam, Maroun Nemer

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Topology optimization technique presents a potential tool for the design and optimization of structures involved in mass and heat transfer. The method starts with an initial intermediate domain and should be able to progressively distribute the solid and the two fluids exchanging heat. The multi-objective function of the problem takes into account minimization of total pressure loss and maximization of heat transfer between solid and fluid subdomains. Existing methods account for the presence of only one fluid, while the actual work extends optimization distribution of solid and two different fluids. This requires to separate the channels of both fluids and to ensure a minimum solid thickness between them. This is done by adding a third objective function to the multi-objective optimization problem. This article uses density approach where each cell holds two local design parameters ranging from 0 to 1, where the combination of their extremums defines the presence of solid, cold fluid or hot fluid in this cell. Finite volume method is used for direct solver coupled with a discrete adjoint approach for sensitivity analysis and method of moving asymptotes for numerical optimization. Several examples are presented to show the ability of the method to find a trade-off between minimization of power dissipation and maximization of heat transfer while ensuring the separation and continuity of the channel of each fluid without crossing or mixing the fluids. The main conclusion is the possibility to find an optimal bi-fluid domain using topology optimization, defining a fluid to fluid heat exchanger device.

Keywords: topology optimization, density approach, bi-fluid domain, laminar steady state regime, fluid-to-fluid heat exchanger

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Authors: Seyedamirreza Shamsdini, Mohsen Mohammadi

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In this research, 18Ni-300 maraging steel powder particles are investigated by studying particle size distribution along with their morphology and grain structure. The powder analysis shows mostly spherical morphologies with cellular structures. A laser-based additive manufacturing process, selective laser melting (SLM) is used to produce samples for further investigation of mechanical properties and microstructure. Several uniaxial tensile tests are performed on the as-built parts to evaluate the mechanical properties. The macroscopic properties, as well as microscopic studies, are then investigated on the printed parts. Hardness measurements, as well as porosity levels, are measured for each sample and are correlated with microstructures through electron microscopy techniques such as Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The grain structure is studied for the as-printed specimens and compared to the powder particle microstructure. The cellular structure of the printed samples is observed to have dendritic forms with dendrite width dimensions similar to the powder particle cells. The process parameter is changed, and the study is performed for different powder layer thickness, and the resultant mechanical properties and grain structure are shown to be similar. A phase study is conducted both on the powder and the printed samples using X-Ray Diffraction (XRD) techniques, and the austenite phase is observed to at first decrease due to the manufacturing process and again during the uniaxial tensile deformation. The martensitic structure is formed in the first stage based on the heating cycles of the manufacturing process and the remaining austenite is shown to be transformed to martensite due to different deformation mechanisms.

Keywords: additive manufacturing, maraging steel, mechanical properties, microstructure

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Authors: Mahsa Fathollahzadeh

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The various nanoparticles employed in drug delivery applications include micelles, liposomes, solid lipid nanoparticles, polymeric nanoparticles, functionalized nanoparticles, nanocrystals, cyclodextrins, dendrimers, and nanotubes. Micelles, composed of amphiphilic block copolymers, can encapsulate hydrophobic molecules, allowing for targeted delivery. Liposomes, vesicular structures made up of phospholipids, can encapsulate both hydrophobic and hydrophilic molecules, providing a flexible platform for delivering therapeutic agents. Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) are designed to improve the stability and bioavailability of lipophilic drugs. Polymeric nanoparticles, such as poly(lactic-co-glycolic acid) (PLGA), are biodegradable and can be engineered to release drugs in a controlled manner. Functionalized nanoparticles, coated with targeting ligands or antibodies, can specifically target diseased cells or tissues. Nanocrystals, engineered to have specific surface properties, can enhance the solubility and bioavailability of poorly soluble drugs. Cyclodextrins, doughnut-shaped molecules with hydrophobic cavities, can be complex with hydrophobic molecules, allowing for improved solubility and bioavailability. Dendrimers, branched polymers with a central core, can be designed to deliver multiple therapeutic agents simultaneously. Nanotubes and metallic nanoparticles, such as gold nanoparticles, offer real-time tracking capabilities and can be used to detect biomolecular interactions. The use of these nanoparticles has revolutionized the field of drug delivery, enabling targeted and controlled release of therapeutic agents, reduced toxicity, and improved patient outcomes.

Keywords: nanotechnology, nanopharmaceuticals, drug-delivery, proteins, ligands, nanoparticles, chemistry

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Authors: M. Ali Lotfollahi Yaghin, M. Reza Bagerzadeh Karimi, Ali Rahmani, V. Sadeghi Balkanlou

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Structural engineers have long been trying to develop solutions using the full potential of its composing materials. Therefore, there is no doubt that the structural solution progress is directly related to an increase in materials science knowledge. These efforts in conjunction with up-to-date modern construction techniques have led to an extensive use of composite floors in large span structures. On the other hand, the competitive trends of the world market have long been forcing structural engineers to develop minimum weight and labour cost solutions. A direct consequence of this new design trend is a considerable increase in problems related to unwanted floor vibrations. For this reason, the structural floors systems become vulnerable to excessive vibrations produced by impacts such as human rhythmic activities. The main objective of this paper is to present an analysis methodology for the evaluation of the composite floors human comfort. This procedure takes into account a more realistic loading model developed to incorporate the dynamic effects induced by human walking. The investigated structural models were based on various composite floors, with main spans varying from 5 to 10 m. based on an extensive parametric study the composite floors dynamic response, in terms of peak accelerations, was obtained and compared to the limiting values proposed by several authors and design standards. This strategy was adopted to provide a more realistic evaluation for this type of structure when subjected to vibration due to human walking.

Keywords: vibration, resonance, composite floors, people’s rhythmic movement, dynamic analysis, Abaqus software

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Authors: Natalia Fijol, Aji P. Mathew

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We present the processing and characterisation of three-dimensional (3D) monolith filters based on polylactic acid (PLA) reinforced with various nature-derived nanospecies such as hydroxyapatite, modified cellulose fibers and chitin fibers. The nanospecies of choice were dispersed in PLA through Thermally Induced Phase Separation (TIPS) method. The biocomposites were developed via solvent-assisted blending and the obtained pellets were further single-screw extruded into 3D-printing filaments and processed into various geometries using Fused Deposition Modelling (FDM) technique. The printed prototypes included cubic, cylindrical and hour-glass shapes with diverse patterns of printing infill as well as varying pore structure including uniform and multiple level gradual pore structure. The pores and channel structure as well as overall shape of the prototypes were designed in attempt to optimize the flux and maximize the adsorption-active time. FDM is a cost and energy-efficient method, which does not require expensive tools and elaborated post-processing maintenance. Therefore, FDM offers the possibility to produce customized, highly functional water purification filters with tuned porous structures suitable for removal of wide range of common water pollutants. Moreover, as 3D printing becomes more and more available worldwide, it allows producing portable filters at the place and time where they are most needed. The study demonstrates preparation route for the PLA-based, fully biobased composite and their processing via FDM technique into water purification filters, addressing water treatment challenges on an industrial scale.

Keywords: fused deposition modelling, water treatment, biomaterials, 3D printing, nanocellulose, nanochitin, polylactic acid

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Authors: V. A. Okenyi, K. Yang, P. A. M. Basheer

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Concrete structures in service are constantly under the influence of load. Microstructural cracks often develop in them and considering those in the marine environment; these microcracks often serve as a means for transportation of harmful fluids into the concrete. This paper studies the influence of flexural tensile stress that structural elements undergo on the transport properties of such concrete in the tensile zone of the structural member. Reinforced concrete beams of 1200mm ⨉ 230mm ⨉ 150mm in dimension in a four-point bending set up were subjected to various levels of the loading required to cause a microcrack width of 100µm. The use of Autoclam permeability tests, sorptivity tests as well as the Permit chloride ion migration tests were employed, and results showed that air permeability, sorptivity and water permeability all increased as the load increased in the concrete tensile zone. For air permeability, an increase in stress levels led to more permeability, and the addition of steel macrofibers had no significant effect until at 75% of stress level where it decreased air permeability. For sorptivity, there was no absorption into concrete when no load was added, but water sorptivity index was high at 75% stress levels and higher in steel fiber reinforced concrete (SFRC). Steel macrofibers produced more water permeability into the concrete at 75% stress level under the 100µm crack width considered while steel macrofibers helped in slightly reducing the migration of chloride into concrete by 8.8% reduction, compared to control samples at 75% stress level. It is clear from this research that load-induced cracking leads to an increase in fluid permeability into concrete and the effect of the addition of steel macrofiber to concrete for durability is not significant under 100µm crack width.

Keywords: durability, microcracks, SFRC, stress Level, transport properties

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Authors: Ma. Doreen E. Candelaria, Ma. Louise Margaret A. Ramos, Dr. Jaime Y. Hernandez, Jr

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Bamboo has been introduced as a possible alternative to some construction materials nowadays. Its potential use in the field of engineering, however, is still not widely practiced due to insufficient engineering knowledge on the material’s properties and characteristics. Although there are researches and studies proving its advantages, it is still not enough to say that bamboo can sustain and provide the strength and capacity required of common structures. In line with this, a more detailed analysis was made to observe the layered structure of the bamboo, particularly the species of Kawayan Tinik. It is the main intent of this research to provide the necessary experiments to determine the tensile strength of dried bamboo samples. The test includes tensile strength parallel to fibers with samples taken at internodes only. Throughout the experiment, methods suggested by the International Organization for Standardization (ISO) were followed. The specimens were tested using 3366 INSTRON Universal Testing Machine, with a rate of loading set to 0.6 mm/min. It was then observed from the results of these experiments that dried bamboo samples recorded high layered tensile strengths, as high as 600 MPa. Likewise, along the culm’s length and across its cross section, higher tensile strength were observed at the top part and at its outer layers. Overall, the top part recorded the highest tensile strength per layer, with its outer layers having tensile strength as high as 600 MPa. The recorded tensile strength of its middle and inner layers, on the other hand, were approximately 450 MPa and 180 MPa, respectively. From this variation in tensile strength across the cross section, it may be concluded that an increase in tensile strength may be observed towards the outer periphery of the bamboo. With these preliminary investigations on the layered tensile strength of bamboo, it is highly recommended to conduct experimental investigations on the layered compressive strength properties as well. It is also suggested to conduct investigations evaluating perpendicular layered tensile strength of the material.

Keywords: bamboo strength, layered strength tests, strength test, tensile test

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Authors: Aparna M. Joshi

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Methyl vinyl silicone polymer (VMQ) - alkaline earth metal doped aluminium oxide composites are prepared by conventional two rolls open mill mixing method. Doped aluminium oxides (DAO) using silvery white coloured alkaline earth metals such as Mg and Ca as dopants in the concentration of 0.4 % are synthesized by microwave combustion method and referred as MA ( Mg doped aluminium oxide) and CA ( Ca doped aluminium oxide). The as-synthesized materials are characterized for the electrical resistance, X–ray diffraction, FE-SEM, TEM and FTIR. The electrical resistances of the DAOs are observed to be ~ 8-20 MΩ. This means that the resistance of aluminium oxide (Corundum) α-Al2O3 which is ~ 1010Ω is reduced by the order of ~ 103 to 104 Ω after doping. XRD studies reveal the doping of Mg and Ca in aluminium oxide. The microstructural study using FE-SEM shows the flaky clusterous structures with the thickness of the flakes between 10 and 20 nm. TEM images depict the rod-shaped morphological geometry of the particles with the diameter of ~50-70 nm. The nanocomposites are synthesized by incorporating the DAOs in the concentration of 75 phr (parts per hundred parts of rubber) into VMQ polymer. The electrical resistance of VMQ polymer, which is ~ 1015Ω, drops by the order of 108Ω. There is a retention of the electrical resistance of ~ 30-50 MΩ for the nanocomposites which is a static dissipative range of electricity. In this work white coloured electrically conductive VMQ polymer-DAO nanocomposites (MAVMQ for Mg doping and CAVMQ for Ca doping) have been synthesized. The physical and mechanical properties of the composites such as specific gravity, hardness, tensile strength and rebound resilience are measured. Hardness and tensile strength are found to increase, with the negligible alteration in the other properties.

Keywords: doped aluminium oxide, methyl vinyl silicone polymer, microwave synthesis, static dissipation

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Authors: Jinghua Zhang

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Shaft-tunnel junction is a typical case of the structural nonuniformity in underground structures. The shaft and the tunnel possess greatly different structural features. Even under uniform excitations, they tend to behave discrepantly. Studies on shaft-tunnel junctions are mainly performed numerically. Shaking table tests are also conducted. Although many numerical and experimental data are obtained, an analytical solution still has great merits of gaining more insights into the shaft-tunnel problem. This paper will try to remedy the situation. Since the seismic responses of shaft-tunnel junctions are very related to directions of the excitations, they are studied in two scenarios: the longitudinal-excitation scenario and the transverse-excitation scenario. The former scenario will be addressed in this paper. Given that responses of the tunnel are highly dependent on the shaft, the analytical solutions would be developed firstly for the vertical shaft. Then, the seismic responses of the tunnel would be discussed. Since vertical shafts bear a resemblance to rigid caissons, the solution proposed in this paper is derived by introducing terms of shaft-tunnel and soil-tunnel interactions into equations originally developed for rigid caissons. The validity of the solution is examined by a validation model computed by finite element method. The mutual influence between the shaft and the tunnel is introduced. The soil-structure interactions are discussed parametrically based on the proposed equations. The shaft-tunnel relative displacement and the soil-tunnel relative stiffness are found to be the most important parameters affecting the magnitudes and distributions of the internal forces of the tunnel. A hinge-joint at the shaft-tunnel junction could significantly reduce the degree of stress concentration compared with a rigid joint.

Keywords: analytical solution, longitudinal excitation, numerical validation , shaft-tunnel junction

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Authors: Hsuan Yu Lai, Hsuan Hsuan Chang

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The consumer decision process steps through problems by weighing evidence, examining alternatives, and choosing a decision path. Currently, the COVID 19 made the tourism industry encounter a huge challenge and suffer the biggest amount of economic loss. It would be very important to reexamine the decision-making process model, especially after the pandemic, and consider the differences among different generations. The tourism industry has been significantly impacted by the global outbreak of COVID-19, but as the pandemic subsides, the sector is recovering. This study addresses the scarcity of research on travel decision-making patterns among generations in Taiwan. Specifically targeting individuals who frequently traveled abroad before the pandemic, the study explores differences in decision-making at different stages post-outbreak. So this study investigates differences in travel decision-making among individuals from different generations during/after the COVID-19 pandemic and examines the moderating effects of social media usage and individuals' perception of health risks. The study hypotheses are “there are significant differences in the decision-making process including travel motivation, information searching preferences, and criteria for decision-making” and that social-media usage and health-risk perception would moderate the results of the previous study hypothesis. The X, Y, and Z generations are defined and categorized based on a literature review. The survey collected data including their social-economic background, travel behaviors, motivations, considerations for destinations, travel information searching preferences, and decision-making criteria before/after the pandemic based on the reviews of previous studies. Data from 656 online questionnaires were collected between January to May 2023 and from Taiwanese travel consumers who used to travel at least one time abroad before Covid-19. SPSS is used to analyze the data with One-Way ANOVA and Two-Way ANOVA. The analysis includes demand perception, information gathering, alternative comparison, purchase behavior, and post-travel experience sharing. Social media influence and perception of health risks are examined as moderating factors. The findings show that before the pandemic, the Y Generation preferred natural environments, while the X Generation favored historical and cultural sites compared to the Z Generation. However, after the outbreak, the Z Generation displayed a significant preference for entertainment activities. This study contributes to understanding changes in travel decision-making patterns following COVID-19 and the influence of social media and health risks. The findings have practical implications for the tourism industry.

Keywords: consumer decision-making, generation study, health risk perception, post-pandemic era, social media

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Authors: Howaida I. Abd-Alla, Amal Z. Hassan, Maha Soltan, Atef G. Hanna, Mounir M. El-Safty

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Acokanthera oblongifolia (Apocynaceae) is used for treatment of several infection diseases and is a well-known cardiac glycoside-containing plant. The infusion of their leaves is gargled to treat tonsillitis and is used medicinally to treat snakebites. The total cardiac glycosides content in the leaves was determined by referring to gitoxigenin as a reference compound. Two triterpenes, lup-20(29)-en-3β-ol (1) and oleanolic acid (2); two cardenolides, acovenoside A (3) and acobioside A (4) were isolated from the ethyl acetate extract. Their structures were determined on the basis of spectral analysis. Major constituents isolated from this species were evaluated for cytotoxicity against normal lung cell line (Wi38) and antimicrobial activities against Gram-positive (two strains) and Gram-negative bacteria (four strains), yeast-like fungi (two strains) and fungi (five strains). The minimum inhibitory concentration (MIC) of the compounds was determined using broth microdilution method. Their viral inhibitory effects against avian influenza virus type A (AI-H5N1) and Newcastle disease virus (NDV) in specific pathogen free (SPF) embryonated chicken eggs (ECE), chicken embryo fibroblasts (CEF) and Vero cells were evaluated. The cardenolide (3) showed viral inhibitory effects against AI-H5N1 and NDV in SPF ECE. The two cardenolides isolated have shown potent cytotoxicity against Vero cells. Compound (3) showed potent anti-Gram-negative bacteria activity. These results suggested that acovenoside A might be promising for future antiviral and antimicrobial drug design.

Keywords: Acokanthera, AI-H5N1, Cardenolides, NDV, SPF-ECE, VERO, Wi38 , Microbe

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Authors: Khawla Almulla

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It is noticed that many Arab intellectuals have called to the need and the importance of enlightenment and its application in their communities, such as Saudi Arabia. To every Islamic state, the Kingdom of Saudi Arabia represents a strategic cornerstone, since it is considered the cradle of Islam. It is the Land of the Two Holy Mosques: the Holy Mosque in Makkah surrounding the Kaaba, towards which all Muslims around the world turn while performing daily prayers and even travel to if possible in order to perform the Hajj (Pilgrimage). It also has the Prophet'ـ‘s Holy Mosque in Al-Madinah Al-Munawarah, which contains the tomb of Prophet Muhammad (pbuh). Therefore, Saudi Arabia occupies an eminent position among Arab and Islamic countries on a religious level. Saudi Arabia has become the most influential country in the Arab world, since it has one-third of the oil resources outside Central Asia, China and Russia .It is the world’s largest producer and exporter of oil. Discovering oil in Saudi Arabia converted it from an important country for Muslims-only to an important country for the major industrial countries and also the developing countries, as well. For various reasons, the diversity of intellectual currents can play a significant role in each community by way of cultural improvement, the development of civilization and the education of people until they become accustomed to accepting or rejecting opinions or ideas which differ from or oppose their own. In addition, the intellectual pluralism and cultural diversity can play a variety of roles. This helps promote dialogue and understanding between different groups or schools of thought. It can also develop cognitive skills, by exchanging ideas and views between different schools and intellectual currents. However, in Saudi Arabia there is much to oppose this plurality. The situation today shows that having a variety of ideologies and differences of cultures are not considered a reasonable way to develop intellectually as an individual or as a country. Rather the opposite is recommended, such that the ideologies of different groups are enough to bring out intellectual conflict and then to the segregation of society. As a consequence, extremism of thought from the different currents in Saudi Arabia has become apparent. This research is of great importance in its exploration of two significant themes. First, it highlights the Saudi Arabian background, in particular the historical, religious and social contexts, in order to understand the background of each religious or liberal movement and find the core of the intellectual differences between them. In addition, the aim of this research is to show the importance of moderation in Islamic thought in Saudi Arabia by tracing the thoughts and views of Dr Salman Al-Odah, whom he has considered to be the most important moderate thinker in Saudi Arabia.

Keywords: Saudi Arabia, intellectual movements, religious movements, extremism, moderation, Salafism, liberalism, Salman Al-Odah

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Authors: Sihyun Chae, Ryoto Arai, Waldo Concepcion, Paula Popescu

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The kidneys perform an important role in the human hormones that regulate the blood pressure, produce an active form of vitamin D and control the production of red blood cells. Kidney disease can cause health problems, such as heart disease. Also, increase the chance of having a stroke or heart attack. There are mainly to types of treatments for kidney disease, dialysis, and kidney transplant. For a better quality of life, the kidney transplant is desirable. However, kidney transplant can cause antibody reaction and patients’ body would be attacked by immune system of their own. For solving that issue, patients with transplanted kidney always take immunosuppressive drugs which can hurt kidney as side effects. Patients willing to do a kidney transplant have a waiting time of 3.6 years in average searching to find an appropriate kidney, considering there are almost 96,380 patients waiting for kidney transplant. There is a promising method to solve these issues: bioartificial kidney. Our membrane is specially designed with unique perforations capable to filter the blood cells separating the white blood cells from red blood cells. White blood cells will not pass through the encapsulated kidney preventing the immune system to attack the new organ and eliminating the need of a matching donor. It is possible to construct life-time long encapsulation without needing pumps or a power supply on the cell’s separation method preventing futures surgeries due the Cross-Channel Flow inside the device. This technology allows the possibility to use an animal kidney, prevent cancer cells to spread through the body, arm and leg transplants in the future. This project aims to improve the quality of life of patients with kidney disease.

Keywords: kidney encapsulation, immunosuppression filter, leukocyte filter, leukocyte

Procedia PDF Downloads 188

Authors: Rajkumar Ghosh

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The Out-of-Sequence Thrust (OOST) is a common phenomenon in collisional tectonic settings like the Himalayas. These OOSTs are activated in different locations at different time frames. These OOST are linked with the multiple Himalayan Thrusts. Apart from minimal documentation in geological mapping for OOST, there exists a lack of field data to establish OOST in the field. This work has considered three thrusts from NW Himalaya in Himachal Pradesh with published data from other sources, allowing a re-examination for correlation of OOST. For the Sutlej section, the approach has been to do fieldwork and microstructural studies. The information related to the cross-cut signature of S/C- and relative time relation could help to predict the nature of OOST. The activation timing, along with the basis of identification of OOST in Higher Himalayan, was documented in various literature. Compilation of the Grain Boundary Migration (GBM) associated temperature range (400–750 °C) was documented from microstructural studies along the Jhakri-Chaura section. No such significant temperature variation across thrusts was observed. Strain variation paths using S Ʌ C angle measurement were carried out along the Jeori-Wangtu transect to distinguish overprinting structures for OOSTs. Near the Chaura Thrust (CT), angular variation of S Ʌ C was documented, and it varies within a range of 15° - 28 °. Along the NH22 (National Highway, 22), all tectonic units of the orogen are exposed in NW Himalaya, INDIA. But there are inherent difficulties in finding field evidence of OOST, largely due to the lack of adequate surface morphology, including topography and drainage pattern.

Keywords: out-of-sequence thrust (OOST), main central thrust (MCT), south tibetan detachment system (STDS), jhakri thrust (JT), sarahan thrust (ST), chaura thrust (CT), higher himalaya (HH), greater himalayan crystalline (GHC)

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Authors: Matthias Haerri, Tobias Huettche, Clemens Kustner

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This article discusses the impact of digitization on business valuation. In order to become and remain ‘digital’, investments are necessary whose return on investment (ROI) often remains vague. This uncertainty is contradictory for a valuation, that rely on predictable cash flows, fixed capital structures and the steady state. However digitisation does not make a company valuation impossible, but traditional approaches must be reconsidered. The authors identify four areas that are to be changing: (1) Tools instead of intuition - In the future, company valuation will neither be art nor science, but craft. This does not require intuition, but experience and good tools. Digital evaluation tools beyond Excel will therefore gain in importance. (2) Real-time instead of deadline - At present, company valuations are always carried out on a case-by-case basis and on a specific key date. This will change with the digitalization and the introduction of web-based valuation tools. Company valuations can thus not only be carried out faster and more efficiently, but can also be offered more frequently. Instead of calculating the value for a previous key date, current and real-time valuations can be carried out. (3) Predictive planning instead of analysis of the past - Past data will also be needed in the future, but its use will not be limited to monovalent time series or key figure analyses. With pictures of ‘black swans’ and the ‘turkey illusion’ it was made clear to us that we build forecasts on too few data points of the past and underestimate the power of chance. Predictive planning can help here. (4) Convergence instead of residual value - Digital transformation shortens the lifespan of viable business models. If companies want to live forever, they have to change forever. For the company valuation, this means that the business model valid on the valuation date only has a limited service life.

Keywords: business valuation, corporate finance, digitisation, disruption

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Authors: Ademilade J. Aboginije, Clinton O. Aigbavboa

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South Africa is among the emerging economy, which has a policy and suitable environment that dynamically stimulates waste management practices of diverting waste away from landfill through prevention, reuse, recycling, and recovery known as the 4R-approaches. The focus of this paper is to investigate the existing structures and processes that are environmentally responsible, then determine the resource-efficiency of the waste management practices in the South Africa construction industry. This paper indicates the results of an investigation carried out by using a systematic review of several related literatures to assess the sustainability of waste management scenarios with secondary material recovery to pinpoint all influential criteria and consequently, highlights a step by step approach to adequately analyze the process by using the indicators that can clearly and fully value the waste management practices in South Africa. Furthermore, a life cycle Analytical tool is used to support the development of a framework which can be applied in measuring the sustainability of existing waste management practices in South Africa. Finding shows that sustainable C&D waste management practices stance a great prospect far more noticeable in terms of job creation and opportunities, saving cost and conserving natural resources when incorporated, especially in the process of recycling and reusing of C&D waste materials in several construction projects in South Africa. However, there are problems such as; inadequacy of waste to energy plants, low compliances to policies and sustainable principles, lack of enough technical capacities confronting the effectiveness of the current waste management practices. Thus, with the increase in the pursuit of sustainable development in most developing countries, this paper determines how sustainability can be measured and used in top-level decision-making policy within construction and demolition waste management for a sustainable built environment.

Keywords: construction industry, green-star rating, life-cycle analysis, sustainability, zero-waste hierarchy

Procedia PDF Downloads 116

Authors: Morteza Raminnia

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In this study, dynamic analysis of functionally graded nano-composite pipe reinforced by single-walled carbon nano-tubes (SWCNTs) with simply supported boundary condition subjected to moving mechanical loads is investigated. The material properties of functionally graded carbon nano tube-reinforced composites (FG-CNTRCs) are assumed to be graded in the thickness direction and are estimated through a micro-mechanical model. In this paper polymeric matrix considered as isotropic material and for the CNTRC, uniform distribution (UD) and three types of FG distribution patterns of SWCNT reinforcements are considered. The system equation of motion is derived by using Hamilton's principle under the assumptions of first order shear deformation theory (FSDT).The thin piezoelectric layers embedded on inner and outer surfaces of FG-CNTRC layer are acted as distributed sensor and actuator to control dynamic characteristics of the FG-CNTRC laminated pipe. The modal analysis technique and Newmark's integration method are used to calculate the displacement and dynamic stress of the pipe subjected to moving loads. The effects of various material distribution and velocity of moving loads on dynamic behavior of the pipe is presented. This present approach is validated by comparing the numerical results with the published numerical results in literature. The results show that the above-mentioned effects play very important role on dynamic behavior of the pipe .This present work shows that some meaningful results that which are interest to scientific and engineering community in the field of FGM nano-structures.

Keywords: nano-composite, functionally garded material, moving load, active control, PZT layers

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Authors: Emilia Klepczarek

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The Basel Committee on Banking Supervision and the OECD found problems with the mechanisms of corporate governance as one of the major causes of destabilization of the financial system and the subprime crisis in the years 2007-2010. In response to these allegations, there were formulated a number of recommendations aimed at improving the quality of supervisory standards in financial institutions. They relate mainly to risk management, remuneration policy, the competence of managers and board members and transparency issues. Nevertheless, a review of the empirical research conducted by the author does not allow for an unambiguous confirmation of the positive impact of the postulated standards on the stability of banking entities. There is, therefore, a presumption of the existence of hidden variables determining the effectiveness of the governance mechanisms. According to the author, this involves concepts arising from behavioral economics and economic anthropology, which allow for an explanation of the effectiveness of corporate governance institutions on the basis of the socio-cultural profile of its members. The proposed corporate governance culture theory indicates that the attributes of the members of the organization and organizational culture can determine the different effectiveness level of the governance processes in similar formal corporate governance structures. The aim of the presentation is, firstly, to draw attention to the vast discrepancies existing within the results of research on the effectiveness of the standards of corporate governance in the banking sector. Secondly, the author proposes an explanation of these differences on the basis of governance theory breaking with common paradigms. The corporate governance culture theory is focused on the identity of the individual and the scope of autonomy offered within his or her institution. The coexistence of these two conditions - the adequate behavioral profile and enough freedom to decide - is a prerequisite for the efficient functioning of the institutions of corporate governance, which can contribute to rehabilitating and strengthening the stability of the financial sector.

Keywords: autonomy, corporate governance, efficiency, governance culture

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Authors: Farzad Danaei, Yilmaz Akkaya

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In many civil engineering applications, especially in the construction of large concrete structures, the early age behavior of concrete has shown to be a crucial problem. The uneven rise in temperature within the concrete in these constructions is the fundamental issue for quality control. Therefore, developing accurate and fast temperature prediction models is essential. The thermal properties of concrete fluctuate over time as it hardens, but taking into account all of these fluctuations makes numerical models more complex. Experimental measurement of the thermal properties at the laboratory conditions also can not accurately predict the variance of these properties at site conditions. Therefore, specific heat capacity and the heat conductivity coefficient are two variables that are considered constant values in many of the models previously recommended. The proposed equations demonstrate that these two quantities are linearly decreasing as cement hydrates, and their value are related to the degree of hydration. The effects of changing the thermal conductivity and specific heat capacity values on the maximum temperature and the time it takes for concrete to reach that temperature are examined in this study using numerical sensibility analysis, and the results are compared to models that take a fixed value for these two thermal properties. The current study is conducted in 7 different mix designs of concrete with varying amounts of supplementary cementitious materials (fly ash and ground granulated blast furnace slag). It is concluded that the maximum temperature will not change as a result of the constant conductivity coefficient, but variable specific heat capacity must be taken into account, also about duration when a concrete's central node reaches its max value again variable specific heat capacity can have a considerable effect on the final result. Also, the usage of GGBFS has more influence compared to fly ash.

Keywords: early-age concrete, mass concrete, specific heat capacity, thermal conductivity coefficient

Procedia PDF Downloads 62

Authors: Matej Patzelt, Jan Dudak, Frantisek Krejci, Jan Zemlicka, Vladimir Musil, Jitka Riedlova, Viktor Sykora, Jana Mrzilkova, Petr Zach

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Introduction: Micro-CT is well used for examination of bone structures and teeth. On the other hand visualization of the soft tissues is still limited. The goal of our study was to create a new fixation method for soft tissue imaging in micro-CT. Methodology: We used organs of 18 mice - heart, lungs, kidneys, liver and brain, which we fixated in ethanol after meticulous preparation. We fixated organs in different concentrations of ethanol and for different period of time. We used three types of ethanol concentration - 97%, 50% and ascending ethanol concentration (25%, 50%, 75%, 97% each for 12 hours). Fixated organs were scanned after 72 hours, 168 hours and 336 hours period of fixation. We scanned all specimens in micro-CT MARS (Medipix All Resolution System). Results: Ethanol method provided contrast enhancement in all studied organs in all used types of fixation. Fixation in 97% ethanol provided very fast fixation and the contrast among the tissues was visible already after 72 hours of fixation. Fixation for the period of 168 and 336 hours gave better details, especially in lung tissue, where alveoli were visualized. On the other hand, this type of fixation caused organs to petrify. Fixation in 50% ethanol provided best results in 336 hours fixation, details were visualized better than in 97% ethanol and samples were not as hard as in fixation in 97% ethanol. Best results were obtained in fixation in ascending ethanol concentration. All organs were visualized in great details, best-visualized organ was heart, where trabeculae and valves were visible. In this type of fixation, organs stayed soft for whole time. Conclusion: New ethanol method is a great option for soft tissue fixation as well as the method for enhancing contrast among tissues in organs. The best results were obtained with fixation of the organs in ascending ethanol concentration, the best visualized organ was the heart.

Keywords: x-ray imaging, small animals, ethanol, ex-vivo

Procedia PDF Downloads 307