Search results for: liquefied natural gas

Authors: Mirco Tarozzi, Giacomo Pignagnoli, Andrea Benedetti

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Structural systems are often subjected to degradation processes due to different kind of phenomena like unexpected loadings, ageing of the materials and fatigue cycles. This is true especially for bridges, in which their safety evaluation is crucial for the purpose of a design of planning maintenance. This paper discusses the experimental evaluation of the stiffness reduction from frequency changes due to uniform damage scenario. For this purpose, a 1:4 scaled bridge has been built in the laboratory of the University of Bologna. It is made of concrete and its cross section is composed by a slab linked to four beams. This concrete deck is 6 m long and 3 m wide, and its natural frequencies have been identified dynamically by exciting it with an impact hammer, a dropping weight, or by walking on it randomly. After that, a set of loading cycles has been applied to this bridge in order to produce a uniformly distributed crack pattern. During the loading phase, either cracking moment and yielding moment has been reached. In order to define the relationship between frequency variation and loss in stiffness, the identification of the natural frequencies of the bridge has been performed, before and after the occurrence of the damage, corresponding to each load step. The behavior of breathing cracks and its effect on the natural frequencies has been taken into account in the analytical calculations. By using a sort of exponential function given from the study of lot of experimental tests in the literature, it has been possible to predict the stiffness reduction through the frequency variation measurements. During the load test also crack opening and middle span vertical displacement has been monitored.

Keywords: concrete bridge, damage detection, dynamic test, frequency shifts, operational modal analysis

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Authors: S. H. Bae, D. W. Cho, W. B. Jeong, J. R. Cho

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Fatigue fracture of an aluminum welded structure is a phenomenon frequently occurring from pores in a weld. In order to grasp the state of the welded structure in operation in real time, the acceleration signal of the structure is measured. At this time, the vibration characteristic of the signal according to the fatigue load is an important parameter of the state diagnosis. This paper was an experimental study on the variation of vibration characteristics of welded beams with vibration aging (especially bending vibration). First simple beams were produced according to welding conditions. Each beam was vibrated and measured beam's PSD (power spectral density) according to the degree of aging. Also, modal testing was conducted to compare the transfer functions of welded beams. Testing result shows that the natural frequencies of the beam changed with the vibration aging due to the change of stiffness in welding part and its stiffness was estimated by the finite element method.

Keywords: modal testing, natural frequency, vibration aging, welded structure

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Authors: Mefteh Bouhalleb

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With the recent progress in nanotechnology, nanofluids have excellent potentiality in many modern engineering processes, particularly for solar systems such as concentrated solar power plants (CSP). In this context, a numerical simulation is performed to investigate laminar natural convection nanofluids in an inclined rectangular enclosure. Mass conservation, momentum, and energy equations are numerically solved by the finite volume element method using the SIMPLER algorithm for pressure-velocity coupling. In this work, we tested the acting factors on the system response time, such as the particle volume fraction of nanoparticles, particle material, particle size, an inclination angle of enclosure and Rayleigh number. The results show that the diameter of solid particles and Rayleigh number plays an important role in the system response time. The orientation angle of the cavity affects the system response time. A phenomenon of hysteresis appears when the system does not return to its initial state.

Keywords: nanofluid, nanoparticles, heat transfer, time response

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Authors: Brayan S. Pabón, R. Ricardo Moreno, Edith Gonzalez

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Inside the wide Colombian natural fiber set is the banana stem leaf, known as Calceta de Plátano, which is a material present in several regions of the country and is a fiber extracted from the pseudo stem of the banana plant (Musa paradisiaca) as a regular maintenance process. Colombia had a production of 2.8 million tons in 2007 and 2008 corresponding to 8.2% of the international production, number that is growing. This material was selected to be studied because it is not being used by farmers due to it being perceived as a waste from the banana harvest and a propagation pest agent inside the planting. In addition, the Calceta does not have industrial applications in Colombia since there is not enough concrete knowledge that informs us about the properties of the material and the possible applications it could have. Based on this situation the industrial design is used as a link between the properties of the material and the need to transform it into industrial products for the market. Therefore, the project identifies potential design attributes that the banana stem leaf can have for product development. The methodology was divided into 2 main chapters: Methodology for the material recognition: -Data Collection, inquiring the craftsmen experience and bibliography. -Knowledge in practice, with controlled experiments and validation tests. -Creation of design attributes and material profile according to the knowledge developed. Moreover, the Design methodology: -Application fields selection, exploring the use of the attributes and the relation with product functions. -Evaluating the possible fields and selection of the optimum application. -Design Process with sketching, ideation, and product development. Different protocols were elaborated to qualitatively determine some material properties of the Calceta, and if they could be designated as design attributes. Once defined, performed and analyzed the validation protocols, 25 design attributes were identified and classified into 4 attribute categories (Environmental, Functional, Aesthetics and Technical) forming the material profile. Then, 15 application fields were defined based on the relation between functions of product and the use of the Calceta attributes. Those fields were evaluated to measure how much are being used the functional attributes. After fields evaluation, a final field was defined , influenced by traditional use of the fiber for packing food. As final result, two products were designed for this application field. The first one is the Multiple Container, which works to contain small or large-thin pieces of food, like potatoes chips or small sausages; it allows the consumption of food with sauces or dressings. The second is the Chorizo container, specifically designed for this food due to the long shape and the consumption mode. Natural fiber research allows the generation of a solider and a more complete knowledge about natural fibers. In addition, the research is a way to strengthen the identity through the investigation of the proper and autochthonous, allowing the use of national resources in a sustainable and creative way. Using divergent thinking and the design as a tool, this investigation can achieve advances in the natural fiber handling.

Keywords: banana stem leaf, Calceta de Plátano, design attributes, natural fibers, product design

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Authors: Elisa Menardo, Margherita Pasini, Margherita Brondino

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A growing body of empirical research from different areas of inquiry suggests that brief contact with natural environment restore mental resources. The Attention Restoration Theory (ART) is the widespread used and empirical founded theory developed to explain why exposure to nature helps people to recovery cognitive resources. It assumes that contact with nature allows people to free (and then recovery) voluntary attention resources and thus allows them to recover from a cognitive fatigue situation. However, it was suggested that some people could have more cognitive benefit after exposure to urban environment. The objective of this study is to report the results of a meta-analysis on studies (peer-reviewed articles) comparing the restorativeness (the quality to be restorative) perceived in natural environments than those perceived in urban environments. This meta-analysis intended to estimate how much nature environments (forests, parks, boulevards) are perceived to be more restorativeness than urban ones (i.e., the magnitude of the perceived restorativeness’ difference). Moreover, given the methodological difference between study, it studied the potential role of moderator variables as participants (student or other), instrument used (Perceived Restorativeness Scale or other), and procedure (in laboratory or in situ). PsycINFO, PsycARTICLES, Scopus, SpringerLINK, Web of Science online database were used to identify all peer-review articles on restorativeness published to date (k = 167). Reference sections of obtained papers were examined for additional studies. Only 22 independent studies (with a total of 1371 participants) met inclusion criteria (direct exposure to environment, comparison between one outdoor environment with natural element and one without natural element, and restorativeness measured by self-report scale) and were included in meta-analysis. To estimate the average effect size, a random effect model (Restricted Maximum-likelihood estimator) was used because the studies included in the meta-analysis were conducted independently and using different methods in different populations, so no common effect-size was expected. The presence of publication bias was checked using trim and fill approach. Univariate moderator analysis (mixed effect model) were run to determine whether the variable coded moderated the perceived restorativeness difference. Results show that natural environments are perceived to be more restorativeness than urban environments, confirming from an empirical point of view what is now considered a knowledge gained in environmental psychology. The relevant information emerging from this study is the magnitude of the estimated average effect size, which is particularly high (d = 1.99) compared to those that are commonly observed in psychology. Significant heterogeneity between study was found (Q(19) = 503.16, p < 0.001;) and studies’ variability was very high (I2[C.I.] = 96.97% [94.61 - 98.62]). Subsequent univariate moderator analyses were not significant. Methodological difference (participants, instrument, and procedure) did not explain variability between study. Other methodological difference (e.g., research design, environment’s characteristics, light’s condition) could explain this variability between study. In the mine while, studies’ variability could be not due to methodological difference but to individual difference (age, gender, education level) and characteristics (connection to nature, environmental attitude). Furthers moderator analysis are working in progress.

Keywords: meta-analysis, natural environments, perceived restorativeness, urban environments

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Authors: Larbi Belagraa

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The universal need to conserve resources, protect the environment and use energy efficiently must necessarily be felt in the field of concrete technology. The recycling of construction and demolition waste as a source of aggregates for the production of concrete has attracted growing interest from the construction industry. In Algeria, the depletion of natural deposits of aggregates and the difficulties in setting up new quarries; makes it necessary to seek new sources of supply, to meet the need for aggregates for the major projects launched by the Algerian government in the last decades. In this context, this work is a part of the approach to provide answers to concerns about the lack of aggregates for concrete. It also aims to develop the inert fraction of demolition materials and mainly concrete construction demolition waste(C&D) as a source of aggregates for the manufacture of new hydraulic concretes based on recycled aggregates. This experimental study presents the results of physical and mechanical characterizations of natural and recycled aggregates, as well as their influence on the properties of fresh and hardened concrete. The characterization of the materials used has shown that the recycled aggregates have heterogeneity, a high water absorption capacity, and a medium quality hardness. However, the limits prescribed by the standards in force do not disqualify these materials of use for application as recycled aggregate concrete type (RAC). The results obtained from the present study show that acceptable mechanical, compressive, and flexural strengths of RACs are obtained using Superplasticizer SP 45 and 5% replacement of cement with silica fume based on recycled aggregates, compared to those of natural concretes. These mechanical performances demonstrate a characteristic resistance at 28 days in compression within the limits of 30 to 40 MPa without any particular suitable technology .to be adapted in the case.

Keywords: recycled aggregates, concrete(RAC), superplasticizer, silica fume, compressive strength

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Authors: Gemma García López

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The goal of this study is to analyze if search queries carried out in search engines such as Google, can offer emotional information about the user that performs them. Knowing the emotional state in which the Internet user is located can be a key to achieve the maximum personalization of content and the detection of worrying behaviors. For this, two studies were carried out using tools with advanced natural language processing techniques. The first study determines if a query can be classified as positive, negative or neutral, while the second study extracts emotional content from words and applies the categorical and dimensional models for the representation of emotions. In addition, we use search queries in Spanish and English to establish similarities and differences between two languages. The results revealed that text search queries performed by users on the Internet can be classified emotionally. This allows us to better understand the emotional state of the user at the time of the search, which could involve adapting the technology and personalizing the responses to different emotional states.

Keywords: emotion classification, text search queries, emotional analysis, sentiment analysis in text, natural language processing

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Authors: Ivan D. Ortega, Juan D. Castro, Alberto Pertuz, Manuel Martinez

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One of the problems considered when scientists talk about climate change is the necessity of utilizing renewable sources of energy, on this category there are many approaches to the problem, one of them is wind energy and wind turbines whose designs have frequently changed along many years trying to achieve a better overall performance on different conditions. From that situation, we get the two main types known today: Vertical and Horizontal axis wind turbines, which have acronyms VAWT and HAWT, respectively. This research aims to understand how well suited a composite material, which is still in development, made with natural origin fibers is for its implementation on vertical axis wind turbines blades under certain wind loads. The study consisted on acquiring the mechanical properties of the materials to be used which where bactris guineenis, also known as pama de lata in Colombia, and adhesive that acts as the matrix which had not been previously studied to the point required for this project. Then, a simplified 3D model of the airfoil was developed and tested under some preliminary loads using finite element analysis (FEA), these loads were acquired in the Colombian Chicamocha Canyon. Afterwards, a more realistic pressure profile was obtained using computational fluid dynamics which took into account the 3D shape of the complete blade and its rotation. Finally, the blade model was subjected to the wind loads using what is known as one way fluidstructure interaction (FSI) and its behavior analyzed to draw conclusions. The observed overall results were positive since the material behaved fairly as expected. Data suggests the material would be really useful in this kind of applications in small to medium size turbines if it is given more attention and time to develop.

Keywords: CFD, FEA, FSI, natural fiber, VAWT

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Authors: Ibrahim Ahmed Jajere

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Resource use conflicts capable of undermining of pastoralists’ livelihoods are on the increase in the North East Arid Zone of Nigeria. In order to expose socio - economic effects of conflicts and benefits of peace, this study assessed cost implications of farmers/pastoralists conflicts over natural resources. Interviews were conducted with 94 farmers, 90 agro-pastoralists and 91 pastoralists’ household heads. The farmers and agro-pastoralists were systematically sampled while pastoralists were located using snowballing. Both farmers and pastoralists suffered losses in the form of injuries to, and even death of household members, and loss of shelter. Farmers sustained losses of facilities and farm produce while pastoralists suffered loss and seizure of livestock, arrest of household members and forced migrations. The material losses in monetary terms amounted to 14,242,200.00 nairas for farmers, a figure higher than the 10,915,500.00 nairas incurred by pastoralists.

Keywords: cost, conflicts, farmers, pastoralists

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Authors: G. Malumbela, E. U. Masuku

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The economy of Botswana has increased extensively since its independence. In contrast to this increase, the construction industry which is one of the key indicators of a developing nation continues to be highly dependent on imported building material products from the neighbouring countries of South Africa, Namibia, Zimbabwe, and Zambia. Only two companies in the country currently blend cement. Even then, the overwhelming majority of raw materials used in the blends are imported. Furthermore, there are no glass manufacturers in Botswana. The ceramic industry is limited to the manufacture of clay bricks notwithstanding a few studios on crockery and sanitary ware which nonetheless use imported clay. This paper presents natural resources and industrial waste products in Botswana that can be used for the development of sustainable building materials. It also investigates at the distribution and cost of other widely used building materials in the country. Finally, the present paper looks at projects and national strategies aimed at a country-wide development of a sustainable building materials industry together with their successes and hitches.

Keywords: Botswana construction industry, construction materials, natural resources, sustainable materials

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Authors: Modi M. Ahmed, Noor Al-Dousari, Ali M. Al-Dousari

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Cornulaca aucheri is an annual herb consider as disturbance indicator currently visible and widely distributed in disturbed lands in Liyah area. Such area is suffered from severe land degradation due to multiple interacting factors such as, overgrazing, gravel and sand quarrying, military activities and natural process. The restoration program is applied after refilled quarries sites and levelled the surface irregularities in order to rehabilitate the natural vegetation and wildlife to its original shape. During the past 10 years of rehabilitation, noticeable greenery healthy cover of Cornulaca sp. are shown specially around artificial lake and playas. The existence of such species in high density it means that restoration program has succeeded and transit from bare ground state to Cornulaca and annual forb state. This state is lower state of Range State Transition Succession model, but it is better than bare soil. Cornulaca spp is native desert plant grows in arid conditions on sandy, stony ground, near oasis, on sand dunes and in sandy depressions. The sheep and goats are repulsive of it. Despite its spiny leaves, it provides good grazing for camels and is said to increase the milk supply produced by lactating females. It is about 80 cm tall and has stems that branched from the base with new faster greenery growth in the summer. It shows good environmental potential to be managed as natural types used for the restoration of degraded lands in desert areas.

Keywords: land degradation, range state transition succession model, rehabilitation, restoration program

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Authors: Zameerpal Kaur

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Ecocriticism comes into existence in 1990s, it tries to explore the relationship of literature with the natural world and further it examines the role that natural surroundings and environment play in the minds of the creative writers during their imagination and creative process. The present study is an attempt to focus on the comparative ecocritical analysis of Shiv Kumar Batalvi and Surjit Patar’s selected poetry in the theoretical framework of ecocriticism in order to shed light on the poet’s vigilant views about the relationship of human life and nature. Shiv Kumar Batalvi is a renowned modern Punjabi poet. He is essentially a poet of nature and love. His opinions towards nature support his position to be considered as a major representative of recent environmental issues and ecocritical concerns in Punjabi literature. He is one of the most outstanding modern Punjabi poets, is endowed with the most artistic temperament in whose poetry nature always has a dominating existence. He seems to consciously portray the scenes of natural surroundings into his poetry; in fact the titles of his poems in themselves signify his love for the nature. Surjit Patar, an imminent modern Punjabi poet tries to present a different picture of nature into his poems; he also uses to write poems about contemporary problems. Surjit Patar’s radical quarrel with the modern cultural context makes him reject all the absolutes and finalities in the form of transcendental reason and religion, history and evolution, he freely writes about the deterioration of nature at selfish materialistic society. He is modern poet who weaves the natural imagery with the syntax of his poems. Patar’s work reflects a universal voice that is dribbled with nuanced humanism and a sense of modernity that seemed neither dated, nor trapped in regional boundaries. Through his poetry he has given a voice to the fragile, disrupting borders, disturbing the status quo. An attempt to analyse the poetic works of above said poets from ecocritical perspective as well as especially focussing on various aspects of ecocriticism like ecocentric ethics, ecoaesthetics, anthropomorphism etc. has been made throughout the comparative study of the selected works.

Keywords: anthropocentrism, degradation, environment and literature, nature

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Authors: Gulcan Sahal, Behzad Nasseri, Ali Akbar Ebrahimi, Isil Seyis Bilkay

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Proteus mirabilis strains which are natural colonizers of healthy individuals’ gastrointestinal tract are also known as common causes of catheter-associated urinary tract infections. Nowadays, as a result of an increased resistance to various antimicrobial drugs, there has been a growing interest in natural products. Therefore, the aim of this study is to investigate biofilm formation of P. mirabilis strains on lemongrass oil containing polycaprolactone nanofibers. Polycaprolactone nanofibers with different lemongrass oil concentrations were successfully prepared by electrospinning and biofilm formation of P. mirabilis on these nanofibers were determined by ‘Crystal Violet Staining Assay’. According to our results, polycaprolactone nanofibers with some lemongrass oil concentrations, decreased biofilm formation of P. mirabilis and this effect increased in parallel with the increase in lemongrass oil concentration. Our results indicate that, polycaprolactone nanofibers with some concentrations of lemongrass oil may provide a treatment against catheter-associated urinary tract infections by means of causing an inhibition on biofilm formation of P. mirabilis.

Keywords: anti-biofilm, biofilm formation, essential oils, nanofibers, proteus mirabilis

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Authors: Kourosh Kosari

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This study is engineering the properties of concrete containing natural nano zeolite as supplementary cementitious material in the blended Portland-cement based binder in amounts of 5,7 and 10% by mass. Crashing of clinoptilolite zeolite is performed by means of planetary ball mill. Two types of concrete along with water to cementitious material ratio (W/(C + P)) in 0.45 and 0.4 at the ages of 7, 28 and 90 days and were compared with each other. The effect of these additives on mechanical properties (compressive and tensile strength) and durability has been investigated by Electrical Resistivity (ER) and Rapid Chloride Penetration Test (RCPT) at the ages 28 and 90 days. Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) revealed that nanoparticles of natural clinoptilolite could improve quality of concrete. As a result of the tests, decrease in penetration of chloride ion and increase electrical resistivity significantly that are appropriate option for controlling of corrosion in reinforced concrete structures but increase of mechanical characteristics is not considerable.

Keywords: ball mill, durability, mechanical properties, nano zeolite

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Authors: Feddal Imene, Boumediene Youssra, Mimanne Goussem

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The history of the environment and its chemistry is above all the history of its pollution. For a large part, it is the changes made in the air, water and soil by human beings. From there, we can define that pollution is an unfavorable modification of the natural environment that appears as a by-product of human action, through direct and indirect effects. The protection and preservation of the environment is one of the pillars of sustainable development, which is currently a major issue for the future of man and the planet. Currently, humanity is facing an alarming increase in the pollution of the natural environment by various organic or inorganic materials. The objective of our work is to study the adsorption of a textile dye which is known in the industrial environment, methyl green, on raw calcic clay. Our material was characterized by X-ray diffraction (XRD) Fourier transform infrared (FTIR), we also determined its cation exchange capacity (CEC), pHzc and specific surface by Methylene Blue method. The kinetic and thermodynamic study of the adsorption of methyl green was studied, these experiments resulted that the adsorption of the dye follows pseudo second order kinetics, and according to the thermodynamic study and the study of the probability we can say that we have a physisorption.

Keywords: calcic clay, dye, materials, environment

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Authors: Po-Ching Wang

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Considering the notable effects of natural resource consumption and impacts on fragile ecosystems, reflection on contemporary sustainable design is critical. Nevertheless, the idea of ‘green’ has been misapplied and even abused, and, in fact, much damage to the environment has been done in its name. In 1996’s popular science fiction film Independence Day, an alien species, having exhausted the natural resources of one planet, moves on to another —a fairly obvious irony on contemporary human beings’ irresponsible use of the Earth’s natural resources in modern times. In fact, the human ambition to master nature and freely access the world’s resources has long been inherent in manifestos evinced by productions of the environmental design professions. Ron Herron’s Walking City, an experimental architectural piece of 1964, is one example that comes to mind here. For this design concept, the architect imagined a gigantic nomadic urban aggregate that by way of an insect-like robotic carrier would move all over the world, on land and sea, to wherever its inhabitants want. Given the contemporary crisis regarding natural resources, recently ideas pertinent to structuring a sustainable environment have been attracting much interest in architecture, a field that has been accused of significantly contributing to ecosystem degradation. Great art, such as Fallingwater building, has been regarded as nature-friendly, but its notion of ‘green’ might be inadequate in the face of the resource demands made by human populations today. This research suggests a more conservative and scrupulous attitude to attempting to modify nature for architectural settings. Designs that pursue spiritual or metaphysical interconnections through anthropocentric aesthetics are not sufficient to benefit ecosystem integrity; though high-tech energy-saving processes may contribute to a fine-scale sustainability, they may ultimately cause catastrophe in the global scale. Design with frugality is proposed in order to actively reduce environmental load. The aesthetic taste and ecological sensibility of design professions and the public alike may have to be reshaped in order to make the goals of environmental sustainability viable.

Keywords: anthropocentric aesthetic, aquarium sustainability, biosphere 2, ecological aesthetic, ecological footprint, frugal design

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Authors: Lorifel Hinay

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Natural disasters have increased in frequency and severity in the Philippines over the years resulting to detrimental impacts in school properties and lives of learners. The topography of the Province of Southern Leyte is a hotspot for inevitable natural disaster-causing hazards that could affect schools, cripple the educational system and cause environmental, cultural and social detrimental impacts making Disaster Risk Reduction and Management (DRRM) an indispensable platform to keep learners safe, secure and resilient. This study determined the schools’ vulnerability and risk assessment to earthquake, landslide, flood, storm surge and tsunami hazards, and its relationship to status in disaster preparedness. Descriptive-correlational research design was used where the respondents were School DRRM Coordinators/School Administrators and Municipal DRRM Officers. It was found that schools’ vulnerability and risk were high in landslide, medium in earthquake, and low in flood, storm surge and tsunami. Though schools were moderately prepared in disasters across all hazards, they were less accomplished in group organization and property security. Less planning preparation and less implementation of DRRM measures were observed in schools highly at risk of earthquake and landslide. Also, schools vulnerable to landslide and flood have very high property security. Topography and location greatly contributed to schools’ vulnerability to hazards, thus, a school-based disaster preparedness plan is hoped to help ensure that hazard-exposed schools can build a culture of safety, disaster resiliency and education continuity.

Keywords: disaster risk reduction and management, earthquake, flood, landslide, storm surge, tsunami

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Authors: Madelaine Venzon, Dany S. S. L. Amaral, André L. Perez, Natália S. Diaz, Juliana A. Martinez Chiguachi, Maira C. M. Fonseca, James D. Harwood, Angelo Pallini

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Integrating strategies of sustainable crop production and promoting the provisioning of ecological services on farms and within rural landscapes is a challenge for today’s agriculture. Habitat management, through increasing vegetational diversity, enhances heterogeneity in agroecosystems and has the potential to improve the recruitment of natural enemies of pests, which promotes biological control services. In tropical agroecosystems, however, there is a paucity of information pertaining to the resources provided by associated plants and their interactions with natural enemies. The maintenance of non-crop plants integrated into and/or surrounding crop fields provides the farmer with a low-investment option to enhance biological control. We carried out field experiments in chili pepper agroecosystems with small stakeholders located in the Zona da Mata, State of Minas Gerais, Brazil, from 2011 to 2015 where we assessed: (a) whether non-crop plants within and around chili pepper fields affect the diversity and abundance of aphidophagous species; (b) whether there are direct interactions between non-crop plants and aphidophagous arthropods; and (c) the importance of non-crop plant resources for survival of Coccinellidae and Chrysopidae species. Aphidophagous arthropods were dominated by Coccinellidae, Neuroptera, Syrphidae, Anthocoridae and Araneae. These natural enemies were readily observed preying on aphids, feeding on flowers or extrafloral nectaries and using plant structures for oviposition and/or protection. Aphid populations were lower on chili pepper fields associated with non-crop plants that on chili pepper monocultures. Survival of larvae and adults of different species of Coccinellidae and Chrysopidae on non-crop resources varied according to the plant species. This research provides evidence that non-crop plants in chili pepper agroecosystems can affect aphid abundance and their natural enemy abundance and survival. It is also highlighting the need for further research to fully characterize the structure and function of plant resources in these and other tropical agroecosystems. Financial support: CNPq, FAPEMIG and CAPES (Brazil).

Keywords: Conservation biological control, aphididae, Coccinellidae, Chrysopidae, plant diversification

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Authors: Preeti Virkar, V. P. Uniyal, Vinod Kumar Bhatt

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With 50% decline in managed honey bee hives in the continents of Europe and America, farmers and landscape managers are turning to native wild bees for their essential ecosystem services of pollination. Wild bees population are too under danger due to the rapid land use changes from anthropogenic activities. With an escalating population reaching 9.0 billion by 2050, human-induced land use changes are predicted to further deteriorate the habitats of numerous species by the turn of this century. The status of bees are uncertain, especially in the tropical regions of the world, which also questions the crisis of global pollinator decline and their essential services to wild and managed flora. Our investigation collectively compares wild native bee diversity and their status in forests and agroecosystems in Doon Valley landscape, situated at the foothills of Himalayan ranges, Uttarakhand, India. We seek to ask whether (1) natural habitat are refuge to richer and rarer bees communities than the agroecosystems, (2) Are agroecosystems closer to natural habitats similar to them than agroecosystems farther away; hence support richer bee communities and hence, (3) Do polyculture farms support richer bee communities than monoculture. The data was collected using observation and pantrap sampling form February to May, 2012 to 2014. We recorded 43 species of bees in Doon Valley. They belonged to 5 families; Megachilidae, Apidae, Andrenidae, Halictidae and Collitidae. A multinomial model approach was used to classify the bees into 2 habitats, in which forests demonstrated to support greater number of specialist (26%, n= 11) species than agroecosystems (7%, n= 3). The valley had many species categorized as the rare (58%, n= 25) and very few generalists (9%, n=4). A linear regression model run on our data demonstrated higher bee diversity in agro-ecosystems in close proximity to forests (H’ for < 200 m = 1.60) compared to those further away (H’ for > 600 m = 0.56) (R2=0.782, SE=0.148, p value=0.004). Organic agriculture supported significantly greater species richness in comparison to conventional farms (Mann-Whitney U test, n1 = 33, n2 = 35; P = 0.001). Forests ecosystems are refuge to rare specialist groups and support bee communities in nearby agroecosystems. The findings of our investigation demonstrate the importance of natural habitats as a potential refuge for rare native wild bee pollinators. Polyculture in the valley behaves similar to natural habitats and supports diverse bee communities in comparison to conventional monocultures. Our study suggests that the farming communities adopt diverse organic agriculture systems to attract wild pollinators beneficial for better crop production. Forests are sanctuaries for bees to nest, forage, and breed. Therefore, our outcome also suggests landscape managers not only preserve protected areas but also enhance the floral diversity in semi-natural and urban areas.

Keywords: native bees, pollinators, polyculture, agroecosystem, natural habitat, diversity, monoculture, specialists, generalists

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Authors: Setareh Shekarsaraei, Marjan Moridi, Nasser L. Hadipour

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In this study, nuclear magnetic resonance spectroscopy and nuclear quadrupole resonance spectroscopy parameters of 14N (Nitrogen in imidazole ring) in N–H…O hydrogen bonding for Histidine hydrochloride monohydrate were calculated via density functional theory. We considered a five-molecule model system of Histidine hydrochloride monohydrate. Also, we examined the trends of environmental effect on hydrogen bonds as well as cooperativity. The functional used in this research is M06-2X which is a good functional and the obtained results have shown good agreement with experimental data. This functional was applied to calculate the NMR and NQR parameters. Some correlations among NBO parameters, NMR, and NQR parameters have been studied which have shown the existence of strong correlations among them. Furthermore, the geometry optimization has been performed using M062X/6-31++G(d,p) method. In addition, in order to study cooperativity and changes in structural parameters, along with increase in cluster size, natural bond orbitals have been employed.

Keywords: hydrogen bonding, density functional theory (DFT), natural bond orbitals (NBO), cooperativity effect

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Authors: Norazam Arbin, Habibis Saleh, Ammar Alsabery, Ishak Hashim

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Double-diffusive natural convection in an open top cavity with partial vertical heating and salting sources is investigated numerically. Different temperatures and concentrations are applied at the source location on the right and left walls while the other remains adiabatic except at the open top surface. Various combinations of sources arrangements are imposed at the vertical walls in order to observe the significant impact to the convection. An iterative finite different method is used to solve the dimensionless governing equations. The effects of Marangoni number and sources arrangements on the contours of streamlines, isotherms, and concentrations are visualized as the outcome of the numerical solutions. The average Nusselt and Sherwood number are presented for various sources arrangements. It is clearly observed that the sources arrangements gave major impact on the heat and mass transfer rates. A horizontal-like pattern is found for sources arrangements that near the top-free surface.

Keywords: double-diffusive, Marangoni effect, partial heating, salting

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Authors: Cheng Yang Kwa, Yoke Rung Wong

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Laminated composite materials are widely employed in automotive, aerospace, and other industries. These materials provide distinct benefits due to their high specific strength, high specific modulus, and ability to be customized for a specific function. However, delamination of laminated composite materials is one of the main defects which can occur during manufacturing, regular operations, or maintenance. Delamination can bring about considerable internal damage, unobservable by visual check, that causes significant loss in strength and stability, leading to composite structure catastrophic failure. Structural health monitoring (SHM) is known to be the automated method for monitoring and evaluating the condition of a monitored object. There are several ways to conduct SHM in aerospace. One of the effective methods is to monitor the natural frequency shift of structure due to the presence of defect. This study investigated the mechanical resonance frequency shift of a multi-layer composite cantilever beam due to interlaminar delamination. ANSYS Workbench® was used to create a 4-plies laminated composite cantilever finite element model with [90/0]s fiber setting. Epoxy Carbon UD (230GPA) Prepreg was chosen, and the thickness was 2.5mm for each ply. The natural frequencies of the finite element model with various degree of delamination were simulated based on modal analysis and then validated by using literature. It was shown that the model without delamination had natural frequency of 40.412 Hz, which was 1.55% different from the calculated result (41.050 Hz). Thereafter, the various degree of delamination was mimicked by changing the frictional conditions at the middle ply-to-ply interface. The results suggested that delamination in the laminated composite cantilever induced a change in its stiffness which alters its mechanical resonance frequency.

Keywords: structural health monitoring, NDT, cantilever, laminate

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Authors: Seyedmahdi Mousavihashemi

Abstract:

Natural Akermanite (NAM) has been successfully prepared by a modified sol-gel method. Optimization in calcination temperature and mechanical ball milling resulted in a pure and nano-sized powder which characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared Spectroscopy (FT–IR). We hypothesized that nano-sized Akermanite (AM) would mimic more efficiently the nanocrystal structure and function of natural bone apatite, owing to the higher surface area, compare to conventional micron-size Akermanite (AM). Accordingly, we used the unique advantage of nanotechnology to improve novel nano akermanite particles as a potential candidate for bone tissue regeneration whether as a per implant filling powder or in combination with other biomaterials as a composite scaffold. Pure Akermanite (PAM) powders were successfully obtained via a simple sol-gel method followed by calcination at 1250 °C. Mechanical grinding in a ceramic ball mill for 7 hours resulted in akermanite (AM) nanoparticles in the range of about 30- 45 nm.

Keywords: biomedical engineering, nano composite, SEM, TEM

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Authors: Lu Song Ma Li Zhi

Abstract:

With the rapid advancement of artificial intelligence technology, large language models (LLMs) have become a milestone in the field of natural language processing, demonstrating remarkable capabilities in semantic understanding, intelligent question answering, and text generation. These models are gradually penetrating various industries, particularly showcasing significant application potential in the data analysis domain. However, retraining or fine-tuning these models requires substantial computational resources and ample downstream task datasets, which poses a significant challenge for many enterprises and research institutions. Without modifying the internal parameters of the large models, prompt engineering techniques can rapidly adapt these models to new domains. This paper proposes a prompt design strategy aimed at leveraging the capabilities of large language models to automate the generation of data analysis code. By carefully designing prompts, data analysis requirements can be described in natural language, which the large language model can then understand and convert into executable data analysis code, thereby greatly enhancing the efficiency and convenience of data analysis. This strategy not only lowers the threshold for using large models but also significantly improves the accuracy and efficiency of data analysis. Our approach includes requirements for the precision of natural language descriptions, coverage of diverse data analysis needs, and mechanisms for immediate feedback and adjustment. Experimental results show that with this prompt design strategy, large language models perform exceptionally well in multiple data analysis tasks, generating high-quality code and significantly shortening the data analysis cycle. This method provides an efficient and convenient tool for the data analysis field and demonstrates the enormous potential of large language models in practical applications.

Keywords: large language models, prompt design, data analysis, code generation

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Authors: Salam Labidi, Sonia Machraoui, Souha Gharbi

Abstract:

Radium isotopes (226Ra, 228Ra) and uranium isotopes (234U, 238U) activity concentrations were determined in most popular Tunisian bottled mineral waters samples. Activity concentrations of uranium were studied by radiochemical separation procedures followed by alpha spectrometry and that of radium isotopes by gamma-ray spectrometry. The activity concentrations of 238U, 234U, 226Ra and 228Ra in water samples varied in range 3.3 - 22.5 mBq.L−1, 4.0 - 34.2 mBq L−1, 2.0 - 67.0 mBq L−1 and 2.0 - 30.2 mBq L−1, respectively. These values are comparable with those reported for many other countries in the world for different types of water. Based on the activity concentration results obtained in this study, the estimated annual ingestion dose rates for three different age groups (babies, children and adults) due to the ingestion of radium and uranium isotopes through drinking water are lower than the limit of intake prescribed by WHO. The annual doses exceed the recommended value of 0.1 mSv y-1 in one case for babies.

Keywords: mineral water, natural radioactivity, radiation dose, radium, uranium

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Authors: Khanom Simarani

Abstract:

Rice husk has been widely reported as a good sorbent for heavy metals. Pre treatment of rice husk minimizes cellulose crystallinity and increases the surface area thus ensuring better adsorption capacity. Commercial base and natural base-treated rice husk were used to investigate the potential of Ni(II) adsorption from synthetic solutions and waste water in batch systems. Effects of process variables such as pH, contact time, adsorbent dose, initial Ni (II) concentration were studied. Optimum Ni (II) adsorption was observed at pH 6 within 60 min of contact time. Experimental data showed increased amount of adsorbed Ni(II) with increasing adsorbent dose and decreased percent of adsorption with increasing initial Ni(II) concentration. Kinetic isotherms (Langmuir, Freundlich) were also applied. Biosorption mechanism of rice husk was analyzed using SEM/EDS, FT-IR, and XRD. The results revealed that natural base produced from agroindustrial waste could be used as efficient as commercial bases during pre treatment rice husk in removing Ni(II) from waste waters within 15 min.

Keywords: Nickel removal, adsorbent, heavy metal, biomass

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Authors: Leonardo Alfredo Mendoza, Cristian Munoz, Marco Aurelio Pacheco, Manoela Kohler, Evelyn Batista, Rodrigo Moura

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Natural Language Processing (NLP) techniques are increasingly more powerful to be able to interpret the feelings and reactions of a person to a product or service. Sentiment analysis has become a fundamental tool for this interpretation but has few applications in languages other than English. This paper presents a classification of sentiment analysis in Portuguese with a base of comments from social networks in Portuguese. A word embedding's representation was used with a 50-Dimension GloVe pre-trained model, generated through a corpus completely in Portuguese. To generate this classification, the bidirectional long short-term memory and bidirectional Gated Recurrent Unit (GRU) models are used, reaching results of 99.1%.

Keywords: natural processing language, sentiment analysis, bidirectional long short-term memory, BI-LSTM, gated recurrent unit, GRU

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Authors: J. Dharmaraj, C. Gunasekaran

Abstract:

Invertebrates are the reliable ecological indicators of disturbance of the forest ecosystems and they respond to environment changes more quickly than other fauna. Among these the terrestrial invertebrates are vital to functioning ecosystems, contributing to processes such as decomposition, nutrient cycling and soil fertility. The natural ecosystems of the forests have been subject to various types of disturbances, which lead to decline of flora and fauna. The comparative diversity of micro-arthropods in natural forest, wattle plantation and eucalyptus plantations were studied in Nilgiris. The study area was divided in to five major sites (Emerald (Site-I), Thalaikundha (Site-II), Kodapmund (Site-III), Aravankad (Site-IV), Kattabettu (Site-V). The research was conducted during period from March 2014 to August 2014. The leaf and soil samples were collected and isolated by using Berlese funnel extraction methods. Specimens were isolated and identified according to their morphology (Balogh 1972). In the present study results clearly showed the variation in soil pH, NPK (Major Nutrients) and organic carbon among the study sites. The chemical components of the leaf litters of the plantation decreased the diversity of micro-arthropods and decomposition rate leads to low amount of carbon and other nutrients present in the soil. Moreover eucalyptus and wattle plantations decreases the availability of the ground water source to other plantations and micro-arthropods and hences affects the soil fertility. Hence, the present study suggests to minimize the growth of wattle and eucalyptus tree plantations in the natural areas which may help to reduce the decline of forests.

Keywords: micro-arthropods, assemblage, berlese funnel, morphology, NPK, nilgiris

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Authors: F. Siahmed, A. Lounis, L. Faghi

Abstract:

The aim of this work is to study mechanical properties of composites based on fiber natural. This material has attracted attention of the scientific community for its mechanical properties, its moderate cost and its specification as regards the protection of environment. In this study the loofah part of the family of the natural fiber has been used for these significant mechanical properties. The fiber has porous structure, which facilitates the impregnation of the resin through these pores. The matrix used in this study is the type of unsaturated polyester. This resin was chosen for its resistance to long term.The work involves: -The chemical treatment of the fibers of loofah by NaOH solution (5%) -The realization of the composite resin / fiber loofah; The preparation of samples for testing -The tensile tests and bending -The observation of facies rupture by scanning electron microscopy The results obtained allow us to observe that the values of Young's modulus and tensile strength in tension is high and open up real prospects. The improvement in mechanical properties has been obtained for the two-layer composite fiber with 7.5% (by weight).

Keywords: loofah fiber, mechanical properties, composite, loofah fiber resin

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Authors: F. Rahimi Dehgolan, S. E. Khadem, S. Bab, M. Najafee

Abstract:

Nowadays, using rotating systems like shafts and disks in industrial machines have been increased constantly. Dynamic stability is one of the most important factors in designing rotating systems. In this study, linear frequencies and stability of a coupled continuous flexible rotor-disk-blades system are studied. The Euler-Bernoulli beam theory is utilized to model the blade and shaft. The equations of motion are extracted using the extended Hamilton principle. The equations of motion have been simplified using the Coleman and complex transformations method. The natural frequencies of the linear part of the system are extracted, and the effects of various system parameters on the natural frequencies and decay rates (stability condition) are clarified. It can be seen that the centrifugal stiffening effect applied to the blades is the most important parameter for stability of the considered rotating system. This result highlights the importance of considering this stiffing effect in blades equation.

Keywords: rotating shaft, flexible blades, centrifugal stiffness, stability

Procedia PDF Downloads 265