Search results for: green composite

Authors: Karolina Mazur, Stanislaw Kuciel

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Polylactides (PLA) and polyhydroxyalkanoates (PHA) are the two groups of biodegradable and biocompatible thermoplastic polymers most commonly utilised in medicine and rehabilitation. The aim of this work is to determine the changes in the strength properties and the microstructures taking place in biodegradable polymer composites during their long-term storage in a highly cooled environment (i.e. a freezer at -24ºC) and to initially assess the durability of such biocomposites when used as single-use elements of rehabilitation or medical equipment. It is difficult to find any information relating to the feasibility of long-term storage of technical products made of PLA or PHA, but nonetheless, when using these materials to make products such as casings of hair dryers, laptops or mobile phones, it is safe to assume that without storing in optimal conditions their degradation time might last even several years. SEM images and the assessment of the strength properties (tensile, bending and impact testing) were carried out and the density and water sorption of two polymers, PLA and PHA (NaturePlast PLE 001 and PHE 001), filled with cellulose fibres (corncob grain – Rehofix MK100, Rettenmaier&Sohne) up to 10 and 20% mass were determined. The biocomposites had been stored at a temperature of -24ºC for 4 years. In order to find out the changes in the strength properties and the microstructure taking place after such a long time of storage, the results of the assessment have been compared with the results of the same research carried out 4 years before. Results shows a significant change in the manner of fractures – from ductile with developed surface for the PHA composite with corncob grain when the tensile testing was performed directly after the injection into a more brittle state after 4 years of storage, which is confirmed by the strength tests, where a decrease of deformation is observed at point of fracture. The research showed that there is a way of storing medical devices made out of PLA or PHA for a reasonably long time, as long as the required temperature of storage is met. The decrease of mechanical properties found during tensile testing and bending for PLA was less than 10% of the tensile strength, while the modulus of elasticity and deformation at fracturing slightly rose, which may implicate the beginning of degradation processes. The strength properties of PHA are even higher after 4 years of storage, although in that case the decrease of deformation at fracturing is significant, reaching even 40%, which suggests its degradation rate is higher than that of PLA. The addition of natural particles in both cases only slightly increases the biodegradation.

Keywords: biocomposites, PLA, PHA, storage

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Authors: Hsin-Yueh Chang, Pin-Chen Liao, Jo-Shu Chang, Chun-Yen Chen

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Biofuel has drawn much attention as a potential substitute to fossil fuels. However, biodiesel from waste oil, oil crops or other oil sources can only satisfy partial existing demands for transportation. Due to the feature of being clean, green and viable for mass production, using microalgae as a feedstock for biodiesel is regarded as a possible solution for a low-carbon and sustainable society. In particular, Thraustochytrium sp. BM2, an indigenous heterotrophic microalga, possesses the potential for metabolizing glycerol to produce lipids. Hence, it is being considered as a promising microalgae-based oil source for biodiesel production and other applications. This study was to optimize the culture pH, scale up, assess the feasibility of producing microalgal lipid from crude glycerol and apply operation strategies following optimal results from shake flask system in a 5L stirred-tank fermenter for further enhancing lipid productivities. Cultivation of Thraustochytrium sp. BM2 without pH control resulted in the highest lipid production of 3944 mg/L and biomass production of 4.85 g/L. Next, when initial glycerol and corn steep liquor (CSL) concentration increased five times (50 g and 62.5 g, respectively), the overall lipid productivity could reach 124 mg/L/h. However, when using crude glycerol as a sole carbon source, direct addition of crude glycerol could inhibit culture growth. Therefore, acid and metal salt pretreatment methods were utilized to purify the crude glycerol. Crude glycerol pretreated with acid and CaCl₂ had the greatest overall lipid productivity 131 mg/L/h when used as a carbon source and proved to be a better substitute for pure glycerol as carbon source in Thraustochytrium sp. BM2 cultivation medium. Engineering operation strategies such as fed-batch and semi-batch operation were applied in the cultivation of Thraustochytrium sp. BM2 for the improvement of lipid production. In cultivation of fed-batch operation strategy, harvested biomass 132.60 g and lipid 69.15 g were obtained. Also, lipid yield 0.20 g/g glycerol was same as in batch cultivation, although with poor overall lipid productivity 107 mg/L/h. In cultivation of semi-batch operation strategy, overall lipid productivity could reach 158 mg/L/h due to the shorter cultivation time. Harvested biomass and lipid achieved 232.62 g and 126.61 g respectively. Lipid yield was improved from 0.20 to 0.24 g/g glycerol. Besides, product costs of three kinds of operation strategies were also calculated. The lowest product cost 12.42 $NTD/g lipid was obtained while employing semi-batch operation strategy and reduced 33% in comparison with batch operation strategy.

Keywords: heterotrophic microalga Thrasutochytrium sp. BM2, microalgal lipid, crude glycerol, fermentation strategy, biodiesel

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Authors: Bagnoud-Velásquez Mariluz, Damergi Eya, Grandjean Dominique, Frédéric Vogel, Ludwig Christian

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The sustainability of algae to biofuel processes is seriously affected by the energy intensive production of fertilizers. Large amounts of nitrogen and phosphorus are required for a large-scale production resulting in many cases in a negative impact of the limited mineral resources. In order to meet the algal bioenergy opportunity it appears crucial the promotion of processes applying a nutrient recovery and/or making use of renewable sources including waste. Hydrothermal (HT) conversion is a promising and suitable technology for microalgae to generate biofuels. Besides the fact that water is used as a “green” reactant and solvent and that no biomass drying is required, the technology offers a great potential for nutrient recycling. This study evaluated the possibility to treat the water HT effluent by the growth of microalgae while producing renewable algal biomass. As already demonstrated in previous works by the authors, the HT aqueous product besides having N, P and other important nutrients, presents a small fraction of organic compounds rarely studied. Therefore, extracted heteroaromatic compounds in the HT effluent were the target of the present research; they were profiled using GC-MS and LC-MS-MS. The results indicate the presence of cyclic amides, piperazinediones, amines and their derivatives. The most prominent nitrogenous organic compounds (NOC’s) in the extracts were carefully examined by their effect on microalgae, namely 2-pyrrolidinone and β-phenylethylamine (β-PEA). These two substances were prepared at three different concentrations (10, 50 and 150 ppm). This toxicity bioassay used three different microalgae strains: Phaeodactylum tricornutum, Chlorella sorokiniana and Scenedesmus vacuolatus. The confirmed IC50 was for all cases ca. 75ppm. Experimental conditions were set up for the growth of microalgae in the aqueous phase by adjusting the nitrogen concentration (the key nutrient for algae) to fit that one established for a known commercial medium. The values of specific NOC’s were lowered at concentrations of 8.5 mg/L 2-pyrrolidinone; 1mg/L δ-valerolactam and 0.5 mg/L β-PEA. The growth with the diluted HT solution was kept constant with no inhibition evidence. An additional ongoing test is addressing the possibility to apply an integrated water cleanup step making use of the existent hydrothermal catalytic facility.

Keywords: hydrothermal process, microalgae, nitrogenous organic compounds, nutrient recovery, renewable biomass

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Authors: Noorizal Huang, Christian Girsang, Mohamad Razi Mansoor

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Shallow gas seepage was first spotted at a central processing platform offshore Malaysia in 2010, acknowledged as Platform T in this paper. Frequent monitoring of the gas seepage was performed through remotely operated vehicle (ROV) baseline survey and a comprehensive geophysical survey was conducted to understand the characteristics of the gas seepage and to ensure that the integrity of the foundation at Platform T was not compromised. The origin of the gas back then was unknown. A soil investigation campaign was performed in 2016 to study the origin of the gas seepage. Two boreholes were drilled; a composite borehole to 150m below seabed for the purpose of soil sampling and in-situ testing and a pilot hole to 155m below the seabed, which was later converted to a fit-for-purpose relief well as an alternate migration path for the gas. During the soil investigation campaign, dissipation tests were performed at several layers which were potentially the source or migration path for the gas. Five (5) soil samples were segregated for headspace test, to identify the gas type which subsequently can be used to identify the origin of the gas. Dissipation tests performed at four depth intervals indicates pore water pressure less than 20 % of the effective vertical stress and appear to continue decreasing if the test had not been stopped. It was concluded that a low to a negligible amount of excess pore pressure exist in clayey silt layers. Results from headspace test show presence of methane corresponding to the clayey silt layers as reported in the boring logs. The gas most likely comes from biogenic sources, feeding on organic matter in situ over a large depth range. It is unlikely that there are large pockets of gas in the soil due to its homogeneous clayey nature and the lack of excess pore pressure in other permeable clayey silt layers encountered. Instead, it is more likely that when pore water at certain depth encounters a more permeable path, such as a borehole, it rises up through this path due to the temperature gradient in the soil. As the water rises the pressure decreases, which could cause gases dissolved in the water to come out of solution and form bubbles. As a result, the gas will have no impact on the integrity of the foundation at Platform T. The fit-for-purpose relief well design as well as adopting headspace testing can be used to address the shallow gas issue at Platform T in a cost effective and efficient manners.

Keywords: dissipation test, headspace test, excess pore pressure, relief well, shallow gas

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Authors: Jorge Martínez-Rodríguez, Esther Pérez-Carrillo, Diana Laura Anchondo Álvarez, Julia Lucía Leal Villarreal, Mariana Juárez Dominguez, Luisa Fernanda Torres Hernández, Daniela Salinas Morales, Erick Heredia-Olea

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Maize tortillas are a staple food in Mexico which are mostly made by nixtamalization, which includes the cooking and steeping of maize kernels in alkaline conditions. The cooking step in nixtamalization demands a lot of energy and also generates nejayote, a water pollutant, at the end of the process. The aim of this study was to reduce the cooking time by adding a maize soaking step before nixtamalization while maintaining the quality properties of masa and tortillas. Maize kernels were soaked for 36 h to increase moisture up to 36%. Then, the effect of different cooking times (0, 5, 10, 15, 20, 20, 25, 30, 35, 45-control and 50 minutes) was evaluated on viscosity profile (RVA) of masa to select the treatments with a profile similar or equal to control. All treatments were left steeping overnight and had the same milling conditions. Treatments selected were 20- and 25-min cooking times which had similar values for pasting temperature (79.23°C and 80.23°C), Maximum Viscosity (105.88 Cp and 96.25 Cp) and Final Viscosity (188.5 Cp and 174 Cp) to those of 45 min-control (77.65 °C, 110.08 Cp, and 186.70 Cp, respectively). Afterward, tortillas were produced with the chosen treatments (20 and 25 min) and for control, then were analyzed for texture, damage starch, colorimetry, thickness, and average diameter. Colorimetric analysis of tortillas only showed significant differences for yellow/blue coordinates (b* parameter) at 20 min (0.885), unlike the 25-minute treatment (1.122). Luminosity (L*) and red/green coordinates (a*) showed no significant differences from treatments with respect control (69.912 and 1.072, respectively); however, 25 minutes was closer in both parameters (73.390 and 1.122) than 20 minutes (74.08 and 0.884). For the color difference, (E), the 25 min value (3.84) was the most similar to the control. However, for tortilla thickness and diameter, the 20-minute with 1.57 mm and 13.12 cm respectively was closer to those of the control (1.69 mm and 13.86 cm) although smaller to it. On the other hand, the 25 min treatment tortilla was smaller than both 20 min and control with 1.51 mm thickness and 13.590 cm diameter. According to texture analyses, there was no difference in terms of stretchability (8.803-10.308 gf) and distance for the break (95.70-126.46 mm) among all treatments. However, for the breaking point, all treatments (317.1 gf and 276.5 gf for 25 and 20- min treatment, respectively) were significantly different from the control tortilla (392.2 gf). Results suggest that by adding a soaking step and reducing cooking time by 25 minutes, masa and tortillas obtained had similar functional and textural properties to the traditional nixtamalization process.

Keywords: tortilla, nixtamalization, corn, lime cooking, RVA, colorimetry, texture, masa rheology

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Authors: G. Ghamrawi, Y. Abunnasr, M. Fawaz, S. Yazigi

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Coastal cities are constantly exposed to environmental degradation and economic regression fueled by rapid and uncontrolled urban growth as well as continuous resource depletion. This is the case of the City of Mina in Tripoli (Lebanon), where lack of awareness to preserve social, ecological, and historical assets, coupled with the increasing development pressures, are threatening the socioeconomic status of the city residents, the quality of life and accessibility to the coast. To address these challenges, a holistic coastal urban design and planning approach was developed to analyze the environmental, political, legal, and socioeconomic context of the city. This approach aims to investigate the potential of balancing urban development with the protection and enhancement of cultural, ecological, and environmental assets under an integrated coastal zone management approach (ICZM). The analysis of Mina's different sectors adopted several tools that include direct field observation, interviews with stakeholders, analysis of available data, historical maps, and previously proposed projects. The findings from the analysis were mapped and graphically represented, allowing the recognition of character zones that become the design intervention units. Consequently, the thesis proposes an urban, city-scale intervention that identifies 6 different character zones (the historical fishing port, Abdul Wahab island, the abandoned Port Said, Hammam el Makloub, the sand beach, and the new developable area) and proposes context-specific design interventions that capitalize on the main characteristics of each zone. Moreover, the intervention builds on the institutional framework of ICZM as well as other studies previously conducted for the coast and adopts nature-based solutions with hybrid systems for providing better environmental design solutions for developing the coast. This enables the realization of an all-inclusive, well-connected shoreline with easy and free access towards the sea; a developed shoreline with an active local economy, and an improved urban environment.

Keywords: blue green infrastructure, coastal cities, hybrid solutions, integrated coastal zone management, sustainable development, urban planning

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Authors: Berta Rodrigues Maia, Mariana Marques, Frederica Carvalho

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Introduction: Personality traits play is related to many forms of psychological distress, such as body dissatisfaction. Aim: To explore the associations between appearance schemas and personality traits. Method: 494 Portuguese university students (80.2% females, and 99.2% single), with a mean age of 20.17 years old (SD = 1.77; range: 18-20), filled in the appearance schemas inventory-revised, the NEO personality inventory (a Portuguese short version), and the composite multidimensional perfectionism scale. Results: An independent-samples t-test was conducted to compare the scores in appearance schemas by sex, with a significant difference being found in self-evaluation salience scores [females (M = 37.99, SD = 7.82); males (M = 35.36, SD = 6.60); t (489) = -3.052, p = .002]. Finally, there was no significant difference in motivational salience scores, by sex [females (M = 27.67, SD = 4.84); males (M = 26.70, SD = 4.99); t (489) = -1.748, p = .081]. Having conducted correlations separately, by sex, self-evaluation salience was positively correlated with concern over mistakes (r = .27), doubts about actions (r = .35), and socially prescribed perfectionism (r = .23). moreover, for females, self-evaluation salience was positively correlated with concern over mistakes (r = .34), personal standards (r = .25), doubts about actions (r = .33), parental expectations (r = .24), parental criticism (r = .24), organization (r = .11), socially prescribed perfectionism (r = .31), self-oriented perfectionism (r = .32), and neuroticism (r = .33). concerning motivational salience, in the total sample (not separately, by sex), this scale/dimension significantly correlated with conscientiousness (r = . 18), personal standards (r = .23), socially prescribed perfectionism (r = . 10), and self-oriented perfectionism (r = .29). All correlations were significant at a level of significance of 0.01 (2-tailed), except for socially prescribed perfectionism. All the other correlations (with neuroticism, extroversion, openness, agreeableness, concern over mistakes, doubts about actions, parental expectations, and parental criticism) were not significant. Conclusions: Females seem to value more their self-appearance than males, and, in females, the salience of appearance in life seems to be associated with maladaptive perfectionism, as well as with adaptive perfectionism. In males, the salience of appearance was only related to adaptive perfectionism. These results seem to show that males are more concerned with their own standards regarding appearance, while for females, other's standards are also relevant. In females, the level of the salience of appearance in life seems to relate to the experience of feelings, such as anxiety and depression (neuroticism). The motivation to improve appearance seemed to be particularly related, in both sexes, to adaptive perfectionism (in a general way concerning more the personal standards). Longitudinal studies are needed to clarify the causality of the results. Acknowledgment: This study was carried out under the strategic project of the Centre for Philosophical and Humanistic Studies (CEFH) UID/FIL/00683/2019, funded by the Fundação para a Ciência e a Tecnologia (FCT).

Keywords: appearance schemas, personality traits, university students, sex

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Authors: M. Amanipour, J. Towfighi, E. Ganji Babakhani, M. Heidari

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Cylindrical alumina microfiltration membrane (GMITM Corporation, inside diameter=9 mm, outside diameter=13 mm, length= 50 mm) with an average pore size of 0.5 micrometer and porosity of about 0.35 was used as the support for membrane reactor. This support was soaked in boehmite sols, and the mean particle size was adjusted in the range of 50 to 500 nm by carefully controlling hydrolysis time, and calcined at 650 °C for two hours. This process was repeated with different boehmite solutions in order to achieve an intermediate layer with an average pore size of about 50 nm. The resulting substrate was then coated with a thin and dense layer of silica by counter current chemical vapour deposition (CVD) method. A boehmite sol with 10 wt.% of nickel which was prepared by a standard procedure was used to make the catalytic layer. BET, SEM, and XRD analysis were used to characterize this layer. The catalytic membrane reactor was placed in an experimental setup to evaluate the permeation and hydrogen separation performance for a steam reforming reaction. The setup consisted of a tubular module in which the membrane was fixed, and the reforming reaction occurred at the inner side of the membrane. Methane stream, diluted with nitrogen, and deionized water with a steam to carbon (S/C) ratio of 3.0 entered the reactor after the reactor was heated up to 500 °C with a specified rate of 2 °C/ min and the catalytic layer was reduced at presence of hydrogen for 2.5 hours. Nitrogen flow was used as sweep gas through the outer side of the reactor. Any liquid produced was trapped and separated at reactor exit by a cold trap, and the produced gases were analyzed by an on-line gas chromatograph (Agilent 7890A) to measure total CH₄ conversion and H₂ permeation. BET analysis indicated uniform size distribution for catalyst with average pore size of 280 nm and average surface area of 275 m².g^-1. Single-component permeation tests were carried out for hydrogen, methane, and carbon dioxide at temperature range of 500-800 °C, and the results showed almost the same permeance and hydrogen selectivity values for hydrogen as the composite membrane without catalytic layer. Performance of the catalytic membrane was evaluated by applying membranes as a membrane reactor for methane steam reforming reaction at gas hourly space velocity (GHSV) of 10,000 h⁻¹ and 2 bar. CH₄ conversion increased from 50% to 85% with increasing reaction temperature from 600 °C to 750 °C, which is sufficiently above equilibrium curve at reaction conditions, but slightly lower than membrane reactor with packed nickel catalytic bed because of its higher surface area compared to the catalytic layer.

Keywords: catalytic membrane, hydrogen, methane steam reforming, permeance

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Authors: Ozcan Yavas, Berrak Erol Nalbur, Sermin Gunarslan

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A materiality matrix is a tool that organizations use to prioritize their activities and adapt to the increasing sustainability requirements in recent years. For the materiality index to move from business models to the sustainability business model stage, it must be done with all partners in the raw material, supply, production, product, and end-of-life product stages. Within the scope of this study, the Materiality Matrix was used to transform the business model into a sustainability business model and to create a sustainability roadmap in a factory producing electric buses. This matrix determines the necessary roadmap for all stakeholders to participate in the process, especially in sectors that produce sustainable products, such as the electric vehicle sector, and to act together with the cradle-to-cradle approach of sustainability roadmaps. Global Reporting Initiative analysis was used in the study conducted with 1150 stakeholders within the scope of the study, and 43 questions were asked to the stakeholders under the main headings of 'Legal Compliance Level,' 'Environmental Strategies,' 'Risk Management Activities,' 'Impact of Sustainability Activities on Products and Services,' 'Corporate Culture,' 'Responsible and Profitable Business Model Practices' and 'Achievements in Leading the Sector' and Economic, Governance, Environment, Social and Other. The results of the study aimed to include five 1st priority issues and four 2nd priority issues in the sustainability strategies of the organization in the short and medium term. When the studies carried out in the short term are evaluated in terms of Sustainability and Environmental Risk Management, it is seen that the studies are still limited to the level of legal legislation (60%) and individual studies in line with the strategies (20%). At the same time, the stakeholders expect the company to integrate sustainability activities into its business model within five years (35%) and to carry out projects to become the first company that comes to mind with its success leading the sector (20%). Another result obtained within the study's scope is identifying barriers to implementation. It is seen that the most critical obstacles identified by stakeholders with climate change and environmental impacts are financial deficiency and lack of infrastructure in the dissemination of sustainable products. These studies are critical for transitioning to sustainable business models for the electric vehicle sector to achieve the EU Green Deal and CBAM targets.

Keywords: sustainability business model, materiality matrix, electricity bus, carbon neutrality, sustainability management

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Authors: Hala Barakat

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Architecture plays a crucial role in the colonization and organization of spaces, as well as the preservation of cultures and history. As a result of 70 years of occupation, Palestinian land, culture, and history are endangered today. The government of Israel has used architecture to strangulate Palestinians out and seize their land. The occupation has managed to fragment the West Bank and cause sensible scars on the landscape by creating obstacles, barriers, watchtowers, checkpoints, walls, apartheid roads, border devices, and illegal settlements to unjustly claim land from its indigenous population. The apartheid architecture has divided the Palestinian social and urban fabric into pieces, similarly to the Bantustans. The architectural techniques and methods used by the occupation are evidence of prejudice, and while the illegal settlements remain to be condemned by the United Nations, little is being done to officially end this apartheid. Illegal settlements range in scale from individual units to established cities and house more than 60,000 Israeli settlers that immigrated from all over Europe and the United States. Often architecture by Israel is being directed towards expressing ideologies and serving as evidence of its political agenda. More than 78% of what was granted to Palestine after the development of the Green Line in 1948 is under Israeli occupation today. This project aims to map the illegal architecture as a criticism of governmental agendas in the West Bank and Historic Palestinian land. The paper will also discuss the resistance to the newly developed plan for the last Arab village in Jerusalem, Lifta. The illegal architecture has isolated Palestinians from each other and installed obstacles to control their movement. The architecture of occupation has no ethical or humane logic but rather entirely political, administrative, and it should not be left for the silenced architecture to tell the story. Architecture is not being used as a connecting device but rather a way to implement political injustice and spatial oppression. By narrating stories of the architecture of occupation, we can highlight the spatial injustice of the complex apartheid infrastructure. The Israeli government has managed to intoxicate architecture to serve as a divider between cultural groups, allowing the unlawful and unethical architecture to define its culture and values. As architects and designers, the roles we play in the development of illegal settlements must align with the spatial ethics we practice. Most importantly, our profession is not performing architecturally when we design a house with a particular roof color to ensure it would not be mistaken with a Palestinian house and be attacked accidentally.

Keywords: apartheid, illegal architecture, occupation, politics

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Authors: A. Rezaei, M. Huisman, W. Van Paepegem

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Atomic interactions in molecular systems are mainly studied by particle mechanics. Nevertheless, researches have also put on considerable effort to simulate them using continuum methods. In early 2000, simple equivalent finite element models have been developed to study the mechanical properties of carbon nanotubes and graphene in composite materials. Afterward, many researchers have employed similar structural simulation approaches to obtain mechanical properties of nanostructured materials, to simplify interface behavior of fiber-reinforced composites, and to simulate defects in carbon nanotubes or graphene sheets, etc. These structural approaches, however, are limited to small deformations due to complicated local rotational coordinates. This article proposes a method for the finite element simulation of molecular mechanics. For ease in addressing the approach, here it is called Structural Finite Element Molecular Modeling (SFEMM). SFEMM method improves the available structural approaches for large deformations, without using any rotational degrees of freedom. Moreover, the method simulates molecular conformation, which is a big advantage over the previous approaches. Technically, this method uses nonlinear multipoint constraints to simulate kinematics of the atomic multibody interactions. Only truss elements are employed, and the bond potentials are implemented through constitutive material models. Because the equilibrium bond- length, bond angles, and bond-torsion potential energies are intrinsic material parameters, the model is independent of initial strains or stresses. In this paper, the SFEMM method has been implemented in ABAQUS finite element software. The constraints and material behaviors are modeled through two Fortran subroutines. The method is verified for the bond-stretch, bond-angle and bond-torsion of carbon atoms. Furthermore, the capability of the method in the conformation simulation of molecular structures is demonstrated via a case study of a graphene sheet. Briefly, SFEMM builds up a framework that offers more flexible features over the conventional molecular finite element models, serving the structural relaxation modeling and large deformations without incorporating local rotational degrees of freedom. Potentially, the method is a big step towards comprehensive molecular modeling with finite element technique, and thereby concurrently coupling an atomistic domain to a solid continuum domain within a single finite element platform.

Keywords: finite element, large deformation, molecular mechanics, structural method

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Authors: Wasan Ismail Khalil, Hisham Khalid Ahmed, Zainab Ali

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Structural Lightweight Aggregate Concrete (SLWAC) has been developed in recent years because it reduces the dead load, cost, thermal conductivity and coefficient of thermal expansion of the structure. So SLWAC has the advantage of being a relatively green building material. Lightweight Aggregate (LWA) is either occurs as natural material such as pumice, scoria, etc. or as artificial material produced from different raw materials such as expanded shale, clay, slate, etc. The use of SLWAC in Iraq is limited due to the lack in natural LWA. The existence of Iraqi clay deposit with different types and characteristics leads to the idea of producing artificial expanded clay aggregate. The main aim in this work is to present of the properties of artificial LWA produced in the laboratory. Available local bentonite clay which occurs in the Western region of Iraq was used as raw material to produce the LWA. Sodium silicate as liquid industrial waste material from glass plant was mixed with bentonite clay in mix proportion 1:1 by weight. The manufacturing method of the lightweight aggregate including, preparation and mixing of clay and sodium silicate, burning of the mixture in the furnace at the temperature between 750-800˚C for two hours, and finally gradually cooling process. The produced LWA was then crushed to small pieces then screened on standard sieve series and prepared with grading which conforms to the specifications of LWA. The maximum aggregate size used in this investigation is 10 mm. The chemical composition and the physical properties of the produced LWA are investigated. The results indicate that the specific gravity of the produced LWA is 1.5 with the density of 543kg/m3 and water absorption of 20.7% which is in conformity with the international standard of LWA. Many trail mixes were carried out in order to produce LWAC containing the artificial LWA produced in this research. The selected mix proportion is 1:1.5:2 (cement: sand: aggregate) by weight with water to cement ratio of 0.45. The experimental results show that LWAC has oven dry density of 1720 kg/m3, water absorption of 8.5%, the thermal conductivity of 0.723 W/m.K and compressive strength of 23 N/mm2. The SLWAC produced in this research can be used in the construction of different thermal insulated buildings and masonry units. It can be concluded that the SLWA produced in this study contributes to sustainable development by, using industrial waste materials, conserving energy, enhancing the thermal and structural efficiency of concrete.

Keywords: expanded clay, lightweight aggregate, structural lightweight aggregate concrete, sustainable

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Authors: Marita Heyns

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Job insecurity is a distressing phenomenon which has far reaching consequences for both employees and their organizations. Previously, much attention has been given to the link between job insecurity and individual level performance outcomes, while less is known about how subjectively perceived job insecurity might transfer beyond the individual level to affect performance of the organization on an aggregated level. Research focusing on how employees’ fear of job loss might affect the organization’s ability to respond proactively to volatility and drastic change through applying its capabilities of sensing, seizing, and reconfiguring, appears to be practically non-existent. Equally little is known about the potential underlying mechanisms through which job insecurity might affect the dynamic capabilities of an organization. This study examines how job insecurity might affect dynamic organizational capability through trust as an underling process. More specifically, it considered the simultaneous roles of trust at an impersonal (organizational) level as well as trust at an interpersonal level (in leaders and co-workers) as potential underlying mechanisms through which job insecurity might affect the organization’s dynamic capability to respond to opportunities and imminent, drastic change. A quantitative research approach and a stratified random sampling technique enabled the collection of data among 314 managers at four different plant sites of a large South African steel manufacturing organization undergoing dramatic changes. To assess the study hypotheses, the following statistical procedures were employed: Structural equation modelling was performed in Mplus to evaluate the measurement and structural models. The Chi-square values test for absolute fit as well as alternative fit indexes such as the Comparative Fit Index and the Tucker-Lewis Index, the Root Mean Square Error of Approximation and the Standardized Root Mean Square Residual were used as indicators of model fit. Composite reliabilities were calculated to evaluate the reliability of the factors. Finally, interaction effects were tested by using PROCESS and the construction of two-sided 95% confidence intervals. The findings indicate that job insecurity had a lower-than-expected detrimental effect on evaluations of the organization’s dynamic capability through the conducive buffering effects of trust in the organization and in its leaders respectively. In contrast, trust in colleagues did not seem to have any noticeable facilitative effect. The study proposes that both job insecurity and dynamic capability can be managed more effectively by also paying attention to factors that could promote trust in the organization and its leaders; some practical recommendations are given in this regard.

Keywords: dynamic organizational capability, impersonal trust, interpersonal trust, job insecurity

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Authors: Alvin Chun Man Kwok, Wai Sun Chan, Wei Yuan, Joseph Tin Yum Wong

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Cellulose, the most abundant biopolymer, is the major constituent of plant and dinoflagellate cell walls. Thecate dinoflagellates, in particular, are renowned for their remarkable capacity to synthesize intricate cellulosic thecal plates (CTPs). Unlike the extracellular two-dimensional structure of plant cell walls, these CTPs are three-dimensional and reside within the cellular structure itself. The deposition of CTPs occurs with remarkable precision, and their arrangement serves as crucial taxonomic markers. It is noteworthy that these plates possess the hardness of wood, despite the absence of lignin. Partial and prolonged hydrolysis of CTPs results in the formation of uniform long bundles and lowdimensional, modular crystalline whiskers. This observation aligns with the consistent nanomechanical properties, suggesting a CTPboard structure. The unique composition and structural characteristics of CTPs distinguish them from other cellulose-based materials in the natural world. Spectroscopic studies using Raman and FTIR methods indicate a clear low crystallinity index, with the OH shift becoming more distinct following SDS treatment. Birefringence imaging confirms the highly organized structure of CTPs, demonstrating varying degrees of anisotropy in different regions, including both seaward and cytosolic passages. The knockdown of a cellulose synthase enzyme in dinoflagellates resulted in severe malformation of CTPs and hindered the life-cycle transition. Unlike certain other microalgal groups, these unique circum-spherical depositions of CTPs were not pre-fabricated and transported "to site," but synthesized within alveolar sacs at the specific site. Our research is particularly focused on unraveling the mechanisms underlying the biodeposition of CTPs and exploring their potential biotechnological applications. Understanding the processes involved in CTP formation can pave the way for harnessing their unique properties for various practical applications. Dinoflagellates play a crucial role as major agents of algal blooms and are also known for producing anti-greenhouse sulfur compounds such as DMS/DMSP, highlighting the significance of CTPs as a carbon-neutral source of cellulose. Grant acknowledgement: Research in the laboratory are supported by GRF16104523 from Research Grant Council to JTYW.

Keywords: cellulosic thecal plates, dinoflagellates, cellulose, cell wall

Procedia PDF Downloads 63

Authors: José M. Liñeira Del Río, Ramón Rial, Khodor Nasser, María J.G. Guimarey

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The need to develop new lubricants that offer better anti-friction and anti-wear performance in internal combustion vehicles is one of the great challenges of lubrication in the automotive field. The addition of nanoparticles has emerged as a possible solution and, combined with the lubricating power of ionic liquids, may become one of the alternatives to reduce friction losses and wear of the contact surfaces in the conditions to which tribo-pairs are subjected, especially in the contact of the piston rings and the cylinder liner surface. In this study, the improvement in SAE 10W-40 engine oil tribological performance after the addition of magnesium oxide (MgO) nanoadditives and two different phosphonium-based ionic liquids (ILs) was investigated. The nanoparticle characterization was performed by means of transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The tribological properties, friction coefficients and wear parameters of the formulated oil modified with 0.01 wt.% MgO and 1 wt.% ILs compared with the neat 10W-40 oil were performed and analyzed using a ball-on-three-pins tribometer and a 3D optical profilometer, respectively. Further analysis on the worn surface was carried out by Raman spectroscopy and SEM microscopy, illustrating the formation of the protective IL and MgO tribo-films as hybrid additives. In friction tests with sliding steel-steel tribo-pairs, IL3-based hybrid nanolubricant decreased the friction coefficient and wear volume by 7% and 59%, respectively, in comparison with the neat SAE 10W-40, while the one based on IL1 only achieved a reduction of these parameters by 6% and 39%, respectively. Thus, the tribological characterization also revealed that the MgO and IL3 addition has a positive synergy over the commercial lubricant, adequately meeting the requirements for their use in internal combustion engines. In summary, this study has shown that the addition of ionic liquids to MgO nanoparticles can improve the stability and lubrication behavior of MgO nanolubricant and encourages more investigations on using nanoparticle additives with green solvents such as ionic liquids to protect the environment as well as prolong the lifetime of machinery. The improvement in the lubricant properties was attributed to the following wear mechanisms: the formation of a protective tribo-film and the ability of nanoparticles to fill out valleys between asperities, thereby effectively smoothing out the shearing surfaces.

Keywords: lubricant, nanoparticles, phosphonium-based ionic liquids, tribology

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Authors: Rute Martins, Margarida Mascarenhas, Elsa Pereira

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The importance between sport and the natural environment was researched through a systematic literature in order to analyse the available scientific articles on the association of sport -angling also the physical activity, active leisure and recreation- and environmental behaviour. The collected data were gathered within the last five years (from 2013 to April 2018) in the Scopus, Web of Science, ScienceDirect, Sage, Green Leaf Online Library, GreenFile (EBSCO) and Wiley online Library databases. The content analysis based on the qualitative methods employed in this study was made with Nvivo software. Regarding only the inclusion of scientific articles, more than half of the collected papers highlighted tourism as the main area where sports is being researched with regard to the environmental theme. Thus, it is possible to extract a perspective of the orientations of the ecological concerns in the sports tourism industry. As such, in the winter sports, the climate change is already an identified issue, wondering about the impact of the environment on the sports practice. In this context, there is a focus on the possible adaptative strategies, researching the characteristics of the sports tourist and the winter sports industry. Regarding the natural parks and protected areas (such as reefs), most of the research is on the environmental impact of the sports tourism, choosing the conservation and the protection of nature as the core topics. The research of the sports tourist profile is addressed by many articles, where the motives for practice and the environmental values are being scanned, and relations to the recreation specialization, environmental responsibility, environmental education, and place-attachment concepts are being made. Regarding the sustainable management, the sports tourism study area is approaching the research in a more holistic way; exploring the stakeholder’s interconnection, focusing on landscape planning and environmentally sustainable practices of sport tourism organizations. The natural parks, protected areas, coral reefs, and snow areas serve as the preferred case-studies for investigating the environmental impact and the ecotourism, in particular, studied through hiking and diving in the great majority. The results of the study are a valuable resource to understand the importance of the sports tourism in the environmental and sustainable action along with the need of embracing all stakeholders within the relationship between the sport and the natural environment.

Keywords: ecotourism, environmental behaviour, outdoor recreation, sport tourism

Procedia PDF Downloads 141

Authors: D. Desai, J.Dixon, N. Jain, M. Datta

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Microbial infections of scalp consist of symptomatic appearances associated with seborrhoeic dermatitis, folliculitis, furuncles, carbuncles and ringworm. The main causative organisms in these scalp-based infections are bacteria like S. aureus, P. aeruginosa and a fungus M. Furfur. Allopathic treatment of these infections is available and efficient, but occasionally, topical applications have been found to cause side effects. India is known as the botanical garden of the world and considered as the epicentre for utilization of traditional drugs. Many treatments based on herb extracts are commonly used in India. It has been observed treatment with ethnomedicines requires a higher dosage and greater time period. Additionally, repeated applications are required to obtain the full efficacy of the treatment. An attempt has been made to imbibe the traditional knowledge with nanotechnology to generate a proficient therapeutic against scalp infections. We have imbibed metallic nanoparticles with extracts from traditional medicines and propose to formulate an antimicrobial hair massager. Four commonly used herbs for treatment against scalp disorders like Zingiber officinale (ginger), Allium sativum (garlic), Azadirachta indica (neem) leaves and Citrus limon (lemon) peel was taken. 30 gms of dried homogenized powder was obtained and processed for obtaining the aqueous and ethanolic extract by soxhlet apparatus. The extract was dried and reconstituted to obtain working solution of 1mg/ml. Phytochemical analysis for the obtained extract was done. Synthesis of nanoparticles was mediated by incubating 1mM silver nitrate with extracts of various herbs to obtain silver nanoparticles. The formation of the silver nanoparticles (AgNPs) was monitored using UV-Vis spectroscopy. The AgNPs thus obtained were centrifuged and dried. The AgNPs thus formed were characterized by X Ray Diffraction, scanning electron microscopy and transmission electron microscopy. The size of the AgNPs varied from 10-20 nm and was spherical in shape. P. aeruginosa was plated on nutrient agar and comparative antibacterial activity was tested. Comparative antimicrobial potential was calculated for the extracts and the corresponding nanoconstructs. It was found AgNPs were more efficient than their aqueous and ethanolic counterparts except in the ase of C. limon. Statistical analysis was performed to validate the results obtained.

Keywords: ethnomedicine, nanoconstructs, scalp infections, Zingiber officinale

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Authors: Akinwumi Omotayo, Badu-B Apraku, Joseph Olobasola, Petra Abdul Saghir, Yinka Sobowale

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In southwestern Nigeria, climate change has led to loss of at least two months of rainfall. Consequently, only one cycle of maize can now be grown because of the shorter duration of rainy season as against two cycles in the past. The Early and Extra-early maturing varieties of maize were originally developed for the semi-arid and arid zones of West and Central Africa where there are seasonal challenges of water threatening optimum performance of the traditional maize grown, which are commonly late in maturity (115 to 120 days). The early varieties of maize mature in 90 to 95 days; while the Extra-Early maize varieties reach physiological maturity in less than 90 days. It was broadly hypothesized that the extra early varieties of maize could mitigate the effects of climate change in southwestern Nigeria with higher levels of rainfall by reinstating the original two cycles of rain-fed maize crop. Trials were therefore carried out in southwestern Nigeria on the possibility of adapting the extra early maize to mitigate the effects of climate change. The trial was the Mother/Baby design. The mother trial involves the evaluation of extra-early varieties following ideal recommendations and closely supervised centrally at the University research farm and the Agricultural Development Programmes (ADPs). This requires farmers to observe and evaluate the technology and the management regime meant to precede the second stage of evaluation at several satellite farmers field managed by selected farmers. The Baby Trial is expected to provide a realistic assessment of the technology by farmers in their own environment. A stratified selection of thirty farmers for the Baby Trial ensured appropriate representation across the different categories of the farming population by age and gender. Data from the trials indicate that extra early maize can be grown in two cycles rain fed in south west Nigeria and a third and fourth cycle could be obtained with irrigation. However the long duration varieties outyielded the extra early maize in both the mother and baby trials. When harvested green, the extra early maize served as source of food between March and May when there was scarcity of food. This represents a major advantage. The study recommends that further work needs to be done to improve the yield of extra early maize to encourage farmers to adopt.

Keywords: adaptation, climate change, extra early, maize varieties, mitigation

Procedia PDF Downloads 177

Authors: Sonia Bedhiaf-Romdhani

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The sheep (Ovis aries) was domesticated, approximately 11,000 years ago (YBP), in the Fertile Crescent from Asian Mouflon (Ovis Orientalis). The Northern African (NA) sheep is 7,000 years old, represents a remarkable diversity of sheep populations reared under traditional and low input farming systems (LIFS) over millennia. The majority of small ruminants in developing countries are encountered in low input production systems and the resilience of local communities in rural areas is often linked to the wellbeing of small ruminants. Regardless of the rich biodiversity encountered in sheep ecotypes there are four main sheep breeds in the country with 61,6 and 35.4 percents of Barbarine (fat tail breed) and Queue Fine de l’Ouest (thin tail breed), respectively. Phoenicians introduced the Barbarine sheep from the steppes of Central Asia in the Carthaginian period, 3000 years ago. The Queue Fine de l’Ouest is a thin-tailed meat breed heavily concentrated in the Western and the central semi-arid regions. The Noire de Thibar breed, involving mutton-fine wool producing animals, has been on the verge of extinction, it’s a composite black coated sheep breed found in the northern sub-humid region because of its higher nutritional requirements and non-tolerance of the prevailing harsher condition. The D'Man breed, originated from Morocco, is mainly located in the southern oases of the extreme arid ecosystem. A genetic investigation of Tunisian sheep breeds using a genome-wide scan of approximately 50,000 SNPs was performed. Genetic analysis of relationship between breeds highlighted the genetic differentiation of Noire de Thibar breed from the other local breeds, reflecting the effect of past events of introgression of European gene pool. The Queue Fine de l’Ouest breed showed a genetic heterogeneity and was close to Barbarine. The D'Man breed shared a considerable gene flow with the thin-tailed Queue Fine de l'Ouest breed. Native small ruminants breeds, are capable to be efficiently productive if essential ingredients and coherent breeding schemes are implemented and followed. Assessing the status of genetic variability of native sheep breeds could provide important clues for research and policy makers to devise better strategies for the conservation and management of genetic resources.

Keywords: sheep, farming systems, diversity, SNPs.

Procedia PDF Downloads 128

Authors: Fazli Rahim Shinwari, Ulrich Dittmer

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Like many megacities around the world, Kabul is facing severe problems due to the rising frequency of urban flooding. Since 2001, Kabul is experiencing rapid population growth because of the repatriation of refugees and internal migration. Due to unplanned development, green areas inside city and hilly areas within and around the city are converted into new housing towns that had increased runoff. Trenches along the roadside comprise the unplanned drainage network of the city that drains the combined sewer flow. In rainy season overflow occurs, and after streets become dry, the dust particles contaminate the air which is a major cause of air pollution in Kabul city. In this study, a stormwater management model is introduced as a basis for a systematic approach to urban drainage planning in Kabul. For this purpose, Kabul city is delineated into 8 watersheds with the help of one-meter resolution LIDAR DEM. Storm, water management model, is developed for Wazirabad catchment by using available data and literature values. Due to lack of long term metrological data, the model is only run for hourly rainfall data of a rain event that occurred in April 2016. The rain event from 1st to 3rd April with maximum intensity of 3mm/hr caused huge flooding in Wazirabad Catchment of Kabul City. Model-estimated flooding at some points of the catchment as an actual measurement of flooding was not possible; results were compared with information obtained from local people, Kabul Municipality and Capital Region Independent Development Authority. The model helped to identify areas where flooding occurred because of less capacity of drainage system and areas where the main reason for flooding is due to blockage in the drainage canals. The model was used for further analysis to find a sustainable solution to the problem. The option to construct new canals was analyzed, and two new canals were proposed that will reduce the flooding frequency in Wazirabad catchment of Kabul city. By developing the methodology to develop a stormwater management model from digital data and information, the study had fulfilled the primary objective, and similar methodology can be used for other catchments of Kabul city to prepare an emergency and long-term plan for drainage system of Kabul city.

Keywords: urban hydrology, storm water management, modeling, SWMM, GEO-SWMM, GIS, identification of flood vulnerable areas, urban flooding analysis, sustainable urban drainage

Procedia PDF Downloads 131

Authors: Aisyiyah Fauziah Rahmah

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Generally, an urban city has a rapid growth, it has frequent a variety of problems, especially of convenience in public space usage. The density of population in urban areas and the high activity is also indicated as a cause of urban resident lifestyle for the worse in social relationships and allow for the stress. Streets and green space (parks) are the only public space in a residential area which is used as a place to build social activity, to meet and interact with the other housing dweller. The high level of activity and social interaction that occurs will affect the spatial arrangement. It can be effected the space structures in housing more complex. Ease in access to public space is the reason many dweller prefer doing social activities there. Hillier in Carmona et al (2003) explains that the pattern and intensity of movement of individuals is influenced by the configuration of space, even the space structure can be regarded as the single most influential determinant of movements in the space. Whyte in Zhang and Lawson (2009) also suggest some factors such as seats, trees, water and legibility of space encourage people to stay in public outdoor space. Furthermore this activities can attract more activities. Villa Bukit Tidar is a housing in Lowokwaru District which highest number of people in Malang City, so social activity is also high there. It has natural and recreational concept and provided with view of Malang City from heights. This potential is able to attract the people who live there to stay in public outdoor space and doing activities there. From this study we can find whether the ease of access to public space and visual satisfaction of Villa Bukit Tidar housing affect the usage of public space. This study was carried out by observing the streets pattern and plot pattern to know the configuration space of Villa Bukit Tidar housing through values of connectivity and integrity by resulting from space sintax analysis. Distributing questionnaires also carried out to determine the level of satisfaction and importance perception of visual condition in the public space in Villa Bukit Tidar housing through Important Performance Analysis (IPA). Results of this research indicated that the public spaces in Villa Bukit Tidar housing who has high connectivity and integrity is considered to be visually satisfied and it has a higher public space usage than has low connectivity and integrity are considered to be visually dissatisfied.

Keywords: configuration space, visual perception, social activities, public space usage

Procedia PDF Downloads 468

Authors: Ross J. Maestas

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Biofuels are derived from multiple renewable bioenergy feedstocks including animal fats, wood, starchy grains, and oil seeds. Transportation agencies have considered growing the latter two on underutilized and nontraditional lands that they manage, such as in the Right of Way (ROW), abandoned weigh stations, and at maintenance yards. These crops provide the opportunity to generate revenue or supplement fuel once converted and offer a solution to increasing fuel costs and instability by creating a ‘home-grown’ alternative. Biofuels are non-toxic, biodegradable, and emit less Green House Gasses (GHG) than fossil fuels, therefore allowing agencies to meet sustainability goals and regulations. Furthermore, they enable land managers to achieve soil erosion and roadside aesthetic strategies. The research sought to understand if the cultivation of a biofuel feedstock within the Arkansas State Highway Transportation Department’s (AHTD) managed and marginalized lands is feasible by identifying potential land areas and crops. To determine potential plots the parcel data was downloaded from Arkansas’s GIS office. ArcGIS was used to query the data for all variations of the names of property owned by AHTD and a KML file was created that identifies the queried parcel data in Google Earth. Furthermore, biofuel refineries in the state were identified to optimize the harvest to transesterification process. Agricultural data was collected from federal and state agencies and universities to assess various oil seed crops suitable for conversion and suited to grow in Arkansas’s climate and ROW conditions. Research data determined that soybean is the best adapted biofuel feedstock for Arkansas with camelina and canola showing possibilities as well. Agriculture is Arkansas’s largest industry and soybean is grown in over half of the state’s counties. Successful cultivation of a feedstock in the aforementioned areas could potentially offer significant employment opportunity for which the skilled farmers already exist. Based on compiled data, AHTD manages 21,489 acres of marginalized land. The result of the feasibility assessment offer suggestions and guidance should AHTD decide to further investigate this type of initiative.

Keywords: Arkansas highways, biofuels, renewable energy initiative, marginalized lands

Procedia PDF Downloads 308

Authors: N. Pérez-Rodríguez, D. García-Bernet, A. Torrado-Agrasar, J. M. Cruz, A. B. Moldes, J. M. Domínguez

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World economy is based on non-renewable, fossil fuels such as petroleum and natural gas, which entails its rapid depletion and environmental problems. In EU countries, the objective is that at least 20% of the total energy supplies in 2020 should be derived from renewable resources. Biogas, a product of anaerobic degradation of organic substrates, represents an attractive green alternative for meeting partial energy needs. Nowadays, trend to circular economy model involves efficiently use of residues by its transformation from waste to a new resource. In this sense, characteristics of agricultural residues (that are available in plenty, renewable, as well as eco-friendly) propitiate their valorisation as substrates for biogas production. Corn cob is a by-product obtained from maize processing representing 18 % of total maize mass. Corn cob importance lies in the high production of this cereal (more than 1 x 109 tons in 2014). Due to its lignocellulosic nature, corn cob contains three main polymers: cellulose, hemicellulose and lignin. Crystalline, highly ordered structures of cellulose and lignin hinders microbial attack and subsequent biogas production. For the optimal lignocellulose utilization and to enhance gas production in anaerobic digestion, materials are usually submitted to different pretreatment technologies. In the present work, enzymatic hydrolysis, ultrasounds and combination of both technologies were assayed as pretreatments of corn cob for biogas production. Enzymatic hydrolysis pretreatment was started by adding 0.044 U of Ultraflo® L feruloyl esterase per gram of dry corncob. Hydrolyses were carried out in 50 mM sodium-phosphate buffer pH 6.0 with a solid:liquid proportion of 1:10 (w/v), at 150 rpm, 40 ºC and darkness for 3 hours. Ultrasounds pretreatment was performed subjecting corn cob, in 50 mM sodium-phosphate buffer pH 6.0 with a solid: liquid proportion of 1:10 (w/v), at a power of 750W for 1 minute. In order to observe the effect of the combination of both pretreatments, some samples were initially sonicated and then they were enzymatically hydrolysed. In terms of methane production, anaerobic digestion of the corn cob pretreated by enzymatic hydrolysis was positive achieving 290 L CH4 kg MV-1 (compared with 267 L CH4 kg MV-1 obtained with untreated corn cob). Although the use of ultrasound as the only pretreatment resulted detrimentally (since gas production decreased to 244 L CH4 kg MV-1 after 44 days of anaerobic digestion), its combination with enzymatic hydrolysis was beneficial, reaching the highest value (300.9 L CH4 kg MV-1). Consequently, the combination of both pretreatments improved biogas production from corn cob.

Keywords: biogas, corn cob, enzymatic hydrolysis, ultrasound

Procedia PDF Downloads 252

Authors: Donghyun Lee, Cam Nguyen

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Multi-band systems offer a great deal of benefit in modern communication and radar systems. In particular, multi-band antenna-array radar systems with their extended frequency diversity provide numerous advantages in detection, identification, locating and tracking a wide range of targets, including enhanced detection coverage, accurate target location, reduced survey time and cost, increased resolution, improved reliability and target information. An accurate calibration is a critical issue in antenna array systems. The amplitude and phase errors in multi-band and multi-polarization antenna array transceivers result in inaccurate target detection, deteriorated resolution and reduced reliability. Furthermore, the digital beam former without the RF domain phase-shifting is less immune to unfiltered interference signals, which can lead to receiver saturation in array systems. Therefore, implementing integrated front-end architecture, which can support calibration function with low insertion and filtering function from the farthest end of an array transceiver is of great interest. We report a dual K/Ka-band T/R/Calibration switch module with quasi-elliptic dual-bandpass filtering function implementing a Q-enhanced metamaterial transmission line. A unique dual-band frequency response is incorporated in the reception and calibration path of the proposed switch module utilizing the composite right/left-handed meta material transmission line coupled with a Colpitts-style negative generation circuit. The fabricated fully integrated T/R/Calibration switch module in 0.18-μm BiCMOS technology exhibits insertion loss of 4.9-12.3 dB and isolation of more than 45 dB in the reception, transmission and calibration mode of operation. In the reception and calibration mode, the dual-band frequency response centered at 24.5 and 35 GHz exhibits out-of-band rejection of more than 30 dB compared to the pass bands below 10.5 GHz and above 59.5 GHz. The rejection between the pass bands reaches more than 50 dB. In all modes of operation, the IP1-dB is between 4 and 11 dBm. Acknowledgement: This paper was made possible by NPRP grant # 6-241-2-102 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors.

Keywords: microwaves, millimeter waves, T/R switch, wireless communications, wireless communications

Procedia PDF Downloads 145

Authors: A. G. Back

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In the context of global climate change, extreme weather events are increasingly intense and frequent, challenging the adaptability of urban space. In this sense, urban planning is a relevant instrument for addressing, in a systemic manner, various sectoral policies capable of linking the urban agenda to the reduction of social and environmental risks. The Master Plan of the Municipality of Sao Paulo, 2014, presents innovations capable of promoting the transition to sustainability in the urban space. Among such innovations, the following stand out: i) promotion of density in the axes of mass transport involving mixture of commercial, residential, services, and leisure uses (principles related to the compact city); ii) vulnerabilities reduction based on housing policies, including regular sources of funds for social housing and land reservation in urbanized areas; iii) reserve of green areas in the city to create parks and environmental regulations for new buildings focused on reducing the effects of heat island and improving urban drainage. However, long-term implementation involves distributive conflicts and may change in different political, economic, and social contexts over time. Thus, the central objective of this paper is to identify which factors limit or support the implementation of these policies. That is, to map the challenges and interests of converging and/or divergent urban actors in the sustainable urban development agenda and what resources they mobilize to support or limit these actions in the city of Sao Paulo. Recent proposals to amend the urban zoning law undermine the implementation of the Master Plan guidelines. In this context, three interest groups with different views of the city come into dispute: the real estate market, upper middle class neighborhood associations ('not in my backyard' movements), and social housing rights movements. This paper surveys the different interests and visions of these groups taking into account their convergences, or not, with the principles of sustainable urban development. This approach seeks to fill a gap in the international literature on the causes that underpin or hinder the continued implementation of policies aimed at the transition to urban sustainability in the medium and long term.

Keywords: adaptation, ecosystem-based adaptation, interest groups, urban planning, urban transition to sustainability

Procedia PDF Downloads 101

Authors: Icaro V. Soares, Guilherme L. F. Brandao, Ursula D. C. Resende, Glaucio L. Siqueira

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Electrical energy can be wirelessly transmitted through resonant coupled coils that operate in the near-field region. Once in this region, the field has evanescent character, the efficiency of Resonant Wireless Power Transfer (RWPT) systems decreases proportionally with the inverse cube of distance between the transmitter and receiver coils. The commercially available RWPT systems are restricted to short and mid-range applications in which the distance between coils is lesser or equal to the coil size. An alternative to overcome this limitation is applying metamaterial structures to enhance the coupling between coils, thus reducing the field decay along the distance between them. Metamaterials can be conceived as composite materials with periodic or non-periodic structure whose unconventional electromagnetic behaviour is due to its unit cell disposition and chemical composition. This new kind of material has been used in frequency selective surfaces, invisibility cloaks, leaky-wave antennas, among other applications. However, for RWPT it is mainly applied as superlenses which are lenses that can overcome the optical limitation and are made of left-handed media, that is, a medium with negative magnetic permeability and electric permittivity. As RWPT systems usually operate at wavelengths of hundreds of meters, the metamaterial unit cell size is much smaller than the wavelength. In this case, electric and magnetic field are decoupled, therefore the double negative condition for superlenses are not required and the negative magnetic permeability is enough to produce an artificial magnetic medium. In this work, the influence of the magnetic permeability of a metamaterial slab inserted between two loosely coupled coils is studied in order to find the condition that leads to the maximum transmission efficiency. The metamaterial used is formed by a subwavelength unit cell that consist of a capacitor-loaded split ring with an inner spiral that is designed and optimized using the software Computer Simulation Technology. The unit cell permeability is experimentally characterized by the ratio of the transmission parameters between coils measured with and without the presence of the metamaterial slab. Early measurements results show that the transmission coefficient at the resonant frequency after the inclusion of the metamaterial is about three times higher than with just the two coils, which confirms the enhancement that this structure brings to RWPT systems.

Keywords: electromagnetic lens, loosely coupled coils, magnetic permeability, metamaterials, resonant wireless power transfer, subwavelength unit cells

Procedia PDF Downloads 132

Authors: Sayed M. Ahmed, Sawsan S. Darwish, Nagib A. Elmarzugi, Mohammad A. Al-Dosari, Mahmoud A. Adam, Nadia A. Al-Mouallimi

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Historical stone surfaces and architectural heritage may undergo unwanted changes due to the exposure to many physical and chemical deterioration factors, the innovative properties of the nano - materials can have advantageous application in the restoration and conservation of the cultural heritage with relation to the tailoring of new products for protection and consolidation of stone. The current work evaluates the effectiveness of inorganic compatible treatments; based on nanosized particles of silica (SiO2) dispersed in silicon based product, commonly used as a water-repellent/ consolidation for the construction materials affected by different kinds of decay. The nanocomposites obtained by dispersing the silica nanoparticles in polymeric matrices SILRES® BS OH 100 (solventless mixtures of ethyl silicates), in order to obtain a new nanocomposite, with hydrophobic and consolidation properties, to improve the physical and mechanical properties of the stone material. The nanocomposites obtained and pure SILRES® BS OH 100 were applied by brush Experimental stone blocks. The efficacy of the treatments has been evaluated after consolidation and artificial Thermal aging, through capillary water absorption measurements, Ultraviolet-light exposure to evaluate photo-induced and the hydrophobic effects of the treated surface, Scanning electron microscopy (SEM) examination is performed to evaluate penetration depth, re-aggregating effects of the deposited phase and the surface morphology before and after artificialaging. Sterio microscopy investigation is performed to evaluate the resistant to the effects of the erosion, acids and salts. Improving of stone mechanical properties were evaluated by compressive strength tests, colorimetric measurements were used to evaluate the optical appearance. All the results get together with the apparent effect that, silica/polymer nanocomposite is efficient material for the consolidation of artistic and architectural sandstone monuments, completely compatible, enhanced the durability of sandstone toward thermal and UV aging. In addition, the obtained nanocomposite improved the stone mechanical properties and the resistant to the effects of the erosion, acids and salts compared to the samples treated with pure SILRES® BS OH 100 without silica nanoparticles.

Keywords: colorimetric measurements, compressive strength, nanocomposites, porous stone consolidation, silica nanoparticles, sandstone

Procedia PDF Downloads 240

Authors: Madjid Karimirad

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Floating solar was not very well-known in the renewable energy field a decade ago; however, there has been tremendous growth internationally with a Compound Annual Growth Rate (CAGR) of nearly 30% in recent years. To reach the goal of global net-zero emission by 2050, all renewable energy sources including solar should be used. Considering that 40% of the world’s population lives within 100 kilometres of the coasts, floating solar in coastal waters is an obvious energy solution. However, this requires more robust floating solar solutions. This paper tries to enlighten the fundamental requirements in the design of floating solar for offshore installations from the hydrodynamic and offshore engineering points of view. In this regard, a closer look at dynamic characteristics, stochastic behaviour and nonlinear phenomena appearing in this kind of structure is a major focus of the current article. Floating solar structures are alternative and very attractive green energy installations with (a) Less strain on land usage for densely populated areas; (b) Natural cooling effect with efficiency gain; and (c) Increased irradiance from the reflectivity of water. Also, floating solar in conjunction with the hydroelectric plants can optimise energy efficiency and improve system reliability. The co-locating of floating solar units with other types such as offshore wind, wave energy, tidal turbines as well as aquaculture (fish farming) can result in better ocean space usage and increase the synergies. Floating solar technology has seen considerable developments in installed capacities in the past decade. Development of design standards and codes of practice for floating solar technologies deployed on both inland water-bodies and offshore is required to ensure robust and reliable systems that do not have detrimental impacts on the hosting water body. Floating solar will account for 17% of all PV energy produced worldwide by 2030. To enhance the development, further research in this area is needed. This paper aims to discuss the main critical design aspects in light of the load and load effects that the floating solar platforms are subjected to. The key considerations in hydrodynamics, aerodynamics and simultaneous effects from the wind and wave load actions will be discussed. The link of dynamic nonlinear loading, limit states and design space considering the environmental conditions is set to enable a better understanding of the design requirements of fast-evolving floating solar technology.

Keywords: floating solar, offshore renewable energy, wind and wave loading, design space

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Authors: Neeraj Vij, Christian Leber, Kenneth Schmidt

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Introduction: Total knee arthroplasty is a common procedure. It is well known that the biomechanics of the knee do not fully return to their normal state. Motion analysis has been used to study the biomechanics of the knee after total knee arthroplasty. The purpose of this scoping review is to summarize the current use of gait analysis in total knee arthroplasty and to identify the preoperative motion analysis parameters for which a systematic review aimed at determining the reliability and validity may be warranted. Materials and Methods: This IRB-exempt scoping review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist strictly. Five search engines were searched for a total of 279 articles. Articles underwent a title and abstract screening process followed by full-text screening. Included articles were placed in the following sections: the role of gait analysis as a research tool for operative decisions, other research applications for motion analysis in total knee arthroplasty, gait analysis as a tool in predicting radiologic outcomes, gait analysis as a tool in predicting clinical outcomes. Results: Eleven articles studied gait analysis as a research tool in studying operative decisions. Motion analysis is currently used to study surgical approaches, surgical techniques, and implant choice. Five articles studied other research applications for motion analysis in total knee arthroplasty. Other research applications for motion analysis currently include studying the role of the unicompartmental knee arthroplasty and novel physical therapy protocols aimed at optimizing post-operative care. Two articles studied motion analysis as a tool for predicting radiographic outcomes. Preoperative gait analysis has identified parameters than can predict postoperative tibial component migration. 15 articles studied motion analysis in conjunction with clinical scores. Conclusions: There is a broad range of applications within the research domain of total knee arthroplasty. The potential application is likely larger. However, the current literature is limited by vague definitions of ‘gait analysis’ or ‘motion analysis’ and a limited number of articles with preoperative and postoperative functional and clinical measures. Knee adduction moment, knee adduction impulse, total knee range of motion, varus angle, cadence, stride length, and velocity have the potential for integration into composite clinical scores. A systematic review aimed at determining the validity, reliability, sensitivities, and specificities of these variables is warranted.

Keywords: motion analysis, joint replacement, patient-reported outcomes, knee surgery

Procedia PDF Downloads 75

Authors: Alexandru Achim, Tamás Szűcsborus, Viktor Sasi, Ferenc Nagy, Zoltán Jambrik, Attila Nemes, Albert Varga, Călin Homorodean, Olivier F. Bertrand, Zoltán Ruzsa

Abstract:

Aim: Our study aimed to establish the safety and the technical success of distal radial access for balloon aortic valvuloplasty (DR-BAV). The secondary objective was to determine the effectiveness and appropriate role of DR-BAV within half year follow-up. Methods: Clinical and angiographic data from 32 consecutive patients with symptomatic aortic stenosis were evaluated in a prospective pilot single-center study. Between 2020 and 2021, the patients were treated utilizing dual distal radial access with 6-10F compatible balloons. The efficacy endpoint was divided into technical success (successful valvuloplasty balloon inflation at the aortic valve and absence of intra- or periprocedural major complications), hemodynamic success (a reduction of the mean invasive gradient >30%), and clinical success (an improvement of at least one clinical category in the NYHA classification). The safety endpoints were vascular complications (major and minor Valve Academic Research Consortium (VARC)-2 bleeding, diminished or lost arterial pulse or the presence of any pseudo-aneurysm or arteriovenous fistula during the clinical follow-up) and major adverse events, MAEs (the composite of death, stroke, myocardial infarction, and urgent major aortic valve replacement or implantation during the hospital stay and or at one-month follow-up). Results: 32 patients (40 % male, mean age 80 ± 8,5) with severe aortic valve stenosis were included in the study and 4 patients were excluded. Technical success was achieved in all patients (100%). Hemodynamic success was achieved in 30 patients (93,75%). Invasive max and mean gradients were reduced from 73±22 mm Hg and 49±22 mm Hg to 49±19 mm Hg and 20±13 mm Hg, respectively (p = <.001). Clinical success was achieved in 29 patients (90,6%). In total, no major adverse cardiac or cerebrovascular event nor vascular complications (according to VARC 2 criteria) occurred during the intervention. All-cause death at 6 months was 12%. Conclusion: According to our study, dual distal radial artery access is a safe and effective option for balloon aortic valvuloplasty in patients with severe aortic valve stenosis and can be performed in all patients with sufficient lumen diameter. Future randomized studies are warranted to investigate whether this technique is superior to other approaches.

Keywords: mean invasive gradient, distal radial access for balloon aortic valvuloplasty (DR-BAV), aortic valve stenosis, pseudo-aneurysm, arteriovenous fistula, valve academic research consortium (VARC)-2

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