Search results for: subcritical water

Authors: Farzad Hosseini Hossein Abadi, Cristina Prieto Sierra, Cesar Álvarez Díaz

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Predicting streamflow accurately in flashy catchments prone to floods is a major research and operational challenge in hydrological modeling. Recent advancements in deep learning, particularly Long Short-Term Memory (LSTM) networks, have shown to be promising in achieving accurate hydrological predictions at daily and hourly time scales. In this work, a multi-timescale LSTM (MTS-LSTM) network was applied to the context of regional hydrological predictions at an hourly time scale in flashy catchments. The case study includes 40 catchments allocated in the Basque Country, north of Spain. We explore the impact of hyperparameters on the performance of streamflow predictions given by regional deep learning models through systematic hyperparameter tuning - where optimal regional values for different catchments are identified. The results show that predictions are highly accurate, with Nash-Sutcliffe (NSE) and Kling-Gupta (KGE) metrics values as high as 0.98 and 0.97, respectively. A principal component analysis reveals that a hyperparameter related to the length of the input sequence contributes most significantly to the prediction performance. The findings suggest that input sequence lengths have a crucial impact on the model prediction performance. Moreover, employing catchment-scale analysis reveals distinct sequence lengths for individual basins, highlighting the necessity of customizing this hyperparameter based on each catchment’s characteristics. This aligns with well known “uniqueness of the place” paradigm. In prior research, tuning the length of the input sequence of LSTMs has received limited focus in the field of streamflow prediction. Initially it was set to 365 days to capture a full annual water cycle. Later, performing limited systematic hyper-tuning using grid search, revealed a modification to 270 days. However, despite the significance of this hyperparameter in hydrological predictions, usually studies have overlooked its tuning and fixed it to 365 days. This study, employing a simultaneous systematic hyperparameter tuning approach, emphasizes the critical role of input sequence length as an influential hyperparameter in configuring LSTMs for regional streamflow prediction. Proper tuning of this hyperparameter is essential for achieving accurate hourly predictions using deep learning models.

Keywords: LSTMs, streamflow, hyperparameters, hydrology

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Authors: Malahat Rezaee, Mahiran Basri, Raja Noor Zaliha Raja Abdul Rahman, Abu Bakar Salleh

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Sodium diclofenac is one of the most commonly used drugs of nonsteroidal anti-inflammatory drugs (NSAIDs). It is especially effective in the controlling the severe conditions of inflammation and pain, musculoskeletal disorders, arthritis, and dysmenorrhea. Formulation as nanoemulsions is one of the nanoscience approaches that have been progressively considered in pharmaceutical science for transdermal delivery of drug. Nanoemulsions are a type of emulsion with particle sizes ranging from 20 nm to 200 nm. An emulsion is formed by the dispersion of one liquid, usually the oil phase in another immiscible liquid, water phase that is stabilized using surfactant. Palm kernel oil esters (PKOEs), in comparison to other oils; contain higher amounts of shorter chain esters, which suitable to be applied in micro and nanoemulsion systems as a carrier for actives, with excellent wetting behavior without the oily feeling. This research was aimed to study the effect of O/S ratio on stability and rheological behavior of sodium diclofenac loaded and unloaded palm kernel oil esters nanoemulsion systems. The effect of different O/S ratio of 0.25, 0.50, 0.75, 1.00 and 1.25 on stability of the drug-loaded and unloaded nanoemulsion formulations was evaluated by centrifugation, freeze-thaw cycle and storage stability tests. Lecithin and cremophor EL were used as surfactant. The stability of the prepared nanoemulsion formulations was assessed based on the change in zeta potential and droplet size as a function of time. Instability mechanisms including coalescence and Ostwald ripening for the nanoemulsion system were discussed. In comparison between drug-loaded and unloaded nanoemulsion formulations, drug-loaded formulations represented smaller particle size and higher stability. In addition, the O/S ratio of 0.5 was found to be the best ratio of oil and surfactant for production of a nanoemulsion with the highest stability. The effect of O/S ratio on rheological properties of drug-loaded and unloaded nanoemulsion systems was studied by plotting the flow curves of shear stress (τ) and viscosity (η) as a function of shear rate (γ). The data were fitted to the Power Law model. The results showed that all nanoemulsion formulations exhibited non-Newtonian flow behaviour by displaying shear thinning behaviour. Viscosity and yield stress were also evaluated. The nanoemulsion formulation with the O/S ratio of 0.5 represented higher viscosity and K values. In addition, the sodium diclofenac loaded formulations had more viscosity and higher yield stress than drug-unloaded formulations.

Keywords: nanoemulsions, palm kernel oil esters, sodium diclofenac, rheoligy, stability

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Authors: Samson Obiene, Khamati Shilabukha, Geoffrey Muga, James Kairo

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Mangroves play a vital role in the achievement of multiple goals of global sustainable development (SDG’s), particularly SDG SDG 14 (life under water). Their management, however, is faced with several shortcomings arising from inadequate knowledge on the perceptions of their ecosystem services, hence a need to map mangrove goods and services within SDGs while interrogating the disaggregated perceptions. This study therefore aimed at exploring the parities and disparities in attitudes and perceptions of mangrove ecosystem services among community members of Vanga and the link of the ecosystem services (ESs) to specific SDG targets. The study was based at the Kenya-Tanzania transboundary area in Vanga; where a carbon-offset project on mangroves is being up scaled. Mixed methods approach employing surveys, focus group discussions (FGDs) and reviews of secondary data were used in the study. A two stage cluster samplings was used to select the study population and the sample size. FGDs were conducted purposively selecting active participants in mangrove related activities with distinct socio-demographic characteristics. Sampled respondents comprised of males and females of different occupations and age groups. Secondary data review was used to select specific SDG targets against which mangrove ecosystem services identified through a value chain analysis were mapped. In Vanga, 20 ecosystem services were identified and categorized under supporting, cultural and aesthetic, provisioning and regulating services. According to the findings of this study, 63.9% (95% ci 56.6-69.3) perceived of the ESs as very important for economic development, 10.3% (95% ci 0-21.3) viewed them as important for environmental and ecological development while 25.8% (95% ci 2.2-32.8) were not sure of any role they play in development. In the social-economic disaggregation, ecosystem service values were found to vary with the level of interaction with the ecosystem which depended on gender and other social-economic classes within the study area. The youths, low income earners, women and those with low education levels were also identified as the primary beneficiaries of mangrove ecosystem services. The study also found that of the 17 SDGs, mangroves have a potential of influencing the achievement 12, including, SDGs 1, 2, 3, 4, 6, 8 10, 12, 13, 14, 15 and 17 either directly or indirectly. Generally therefore, the local community is aware of the critical importance mangroves for enhanced livelihood and ecological services but challenges in sustainability still occur as a result the diverse values and of the services and the contradicting interests of the different actors around the ecosystem. It is therefore important to consider parities in values and perception to avoid a ‘tragedy of the commons’ while striving to enhance sustainability of the Mangrove ecosystem.

Keywords: sustainable development, community values, socio-demographics, Vanga, mangrove ecosystem services

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Authors: Pushpa Debnath

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Buddhism implies the ultimate methodology to obtain the acknowledgment to get out from cycling existence applied by the sutras. The Buddha’s natural methodology is the highest way of cessation from suffering existence. To be out of it, one must know the suffering before having tentativeness. According to the Buddha’s methodology, one can observe every being suffer from chronologically grasping craving. It is because lack of knowledge that the Buddha finds the four noble truths which are the basic states. These are suffering, the origin of suffering, cessation of suffering, and the path leading to the cessation of suffering. The Buddha describes that birth is suffering, aging is suffering, sickness is suffering, death is suffering, association with the unexpected is suffering, separation from the pleasant is suffering, and not receiving what one desires is suffering, In brief, the five aggregates of clinging are suffering. As the five aggregates are form, feeling, perception, mental formation, and consciousness. These are known as the matter that we identify with “You, Me” or “He.” The second truth cause of suffering is craving which has three types: craving for sense pleasures, craving for existence, and craving for non-existence. The third truth is the obliteration of craving, suffering can be eliminated to attain the Nibbana. The fourth truth is the path of liberation is the noble eight-fold path consisting of the right view, right intention, right speech, right action, right livelihood, right effort, right mindfulness, and right concentration. The six senses are the media of the eye, ear, nose, tongue, body, and mind sense faculties relating with the five aggregates and the six senses objects visual objects, sounds, smells, tastes, touch, and mind-objects that are contained by every visible being. The first five internal sense bases are material while the mind is a non-material phenomenon. Contact with the external world maintains by receiving through the six senses; visual objects through the eye, sounds through the ear, smells through the nose, tastes through the tongue, touch through the body, and mind-objects through sense faculties. These are the six senses a living being experiences by craving. Everything is conglomerated with all senses faculties through the natural phenomenon which are earth, water, fire, and air element. In this analysis, it is believed that beings are well adapted to the natural phenomenon. Everybody has fear of life because we have hatred, delusion, and anger which are the primary resources of falling into (Samsara) continuously that is the continuity of the natural way. These are the reasons for the suffering that chronically self-diluting through the threefold way. These are the roots of the entire beings suffering so the Buddha finds the enlightenment to uproot from cycling existence and the understanding of the natural consequence. When one could uproot ignorance, one could able to realize the ultimate happiness of Nirvana. From the craving of ignorance, everything starts to be present to the future which gives us mental agonies in existence.

Keywords: purification, morality, natural phenomenon, analysis, development of mind, observatory, Nirvana

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Authors: Nothando Gwazani, K. R. Marembo

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An increase in the atmospheric concentration of carbon dioxide (CO₂) from fossil fuel and land use change necessitates identification of strategies for mitigating threats associated with global warming. Oceans are insufficient to offset the accelerating rate of carbon emission. However, the challenges of oceans as a source of reducing carbon footprint can be effectively overcome by the storage of carbon in terrestrial carbon sinks. The gases with special optical properties that are responsible for climate warming include carbon dioxide (CO₂), water vapors, methane (CH₄), nitrous oxide (N₂O), nitrogen oxides (NOₓ), stratospheric ozone (O₃), carbon monoxide (CO) and chlorofluorocarbons (CFC’s). Amongst these, CO₂ plays a crucial role as it contributes to 50% of the total greenhouse effect and has been linked to climate change. Because plants act as carbon sinks, interest in terrestrial carbon sequestration has increased in an effort to explore opportunities for climate change mitigation. Removal of carbon from the atmosphere is a topical issue that addresses one important aspect of an overall strategy for carbon management namely to help mitigate the increasing emissions of CO₂. Thus, terrestrial ecosystems have gained importance for their potential to sequester carbon and reduce carbon sink in oceans, which have a substantial impact on the ocean species. Field data and electromagnetic spectrum bands were analyzed using ArcGIS 10.2, QGIS 2.8 and ERDAS IMAGINE 2015 to examine the vegetation distribution. Satellite remote sensing data coupled with Normalized Difference Vegetation Index (NDVI) was employed to assess future potential changes in vegetation distributions in Eastern Cape Province of South Africa. The observed 5-year interval analysis examines the amount of carbon absorbed using vegetation distribution. In 2015, the numerical results showed low vegetation distribution, therefore increased the acidity of the oceans and gravely affected fish species and corals. The outcomes suggest that the study area could be effectively utilized for carbon sequestration so as to mitigate ocean acidification. The vegetation changes measured through this investigation suggest an environmental shift and reduced vegetation carbon sink, and that threatens biodiversity and ecosystem. In order to sustain the amount of carbon in the terrestrial ecosystems, the identified ecological factors should be enhanced through the application of good land and forest management practices. This will increase the carbon stock of terrestrial ecosystems thereby reducing direct loss to the atmosphere.

Keywords: remote sensing, vegetation dynamics, carbon sequestration, terrestrial carbon sink

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Authors: Xiaoqian Zhang, Ping Zou, Pengcheng Li

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Salt stress is one of the most serious abiotic stresses, and it can lead to the reduction of agricultural productivity. High salt concentration makes it more difficult for roots to absorb water and disturbs the homeostasis of cellular ions resulting in osmotic stress, ion toxicity and generation of reactive oxygen species (ROS). Compared with the normal physiological conditions, salt stress could inhibit the photosynthesis, break metabolic balance and damage cellular structures, and ultimately results in the reduction of crop yield. Therefore it is vital to develop practical methods for improving the salt tolerance of plants. Chitooligomers (COS) is partially depolymerized products of chitosan, which is consisted of D-glucosamine and N-acetyl-D-glucosamine. In agriculture, COS has the ability to promote plant growth and induce plant innate immunity. The bioactivity of COS closely related to its degree of polymerization (DP) and acetylation (DA). However, most of the previous reports fail to mention the function of COS with different DP and DAs in improving the capacity of plants against salt stress. Accordingly, in this study, chitooligomers (COS) with different degrees of DAs were used to test wheat seedlings response to salt stress. In addition, the determined degrees of polymerization (DPs) COS(DP 4-12) and a heterogeneous COS mixture were applied to explore the relationship between the DP of COSs and its effect on the growth of wheat seedlings in response to salt stress. It showed that COSs, the exogenous elicitor, could promote the growth of wheat seedling, reduce the malondialdehyde (MDA) concentration, and increase the activities of antioxidant enzymes. The results of mRNA expression level test for salt stress-responsive genes indicated that COS keep plants away from being hurt by the salt stress via the regulation of the concentration and the increased antioxidant enzymes activities. Moreover, it was found that the activities of COS was closely related to its Das and COS (DA: 50%) displayed the best salt resistance activity to wheat seedlings. The results also showed that COS with different DP could promote the growth of wheat seedlings under salt stress. COS with a DP (6-8) showed better activities than the other tested samples, implied its activity had a close relationship with its DP. After treatment with chitohexaose, chitoheptaose, and chitooctaose, the photosynthetic parameters were improved obviously. The soluble sugar and proline contents were improved by 26.7%-53.3% and 43.6.0%-70.2%, respectively, while the concentration of malondialdehyde (MDA) was reduced by 36.8% - 49.6%. In addition, the antioxidant enzymes activities were clearly activated. At the molecular level, the results revealed that they could obviously induce the expression of Na+/H+ antiporter genes. In general, these results were fundamental to the study of action mechanism of COS on promoting plant growth under salt stress and the preparation of plant growth regulator.

Keywords: chitooligomers (COS), degree of polymerization (DP), degree of acetylation (DA), salt stress

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Authors: Steven Hidalgo, Patricio Neumann

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The growth of societies has increased the consumption of raw materials and food obtained from nature. This has influenced the services offered by ecosystems to humans, mainly supply and regulation services. One of the indicators used to evaluate these services is Net Primary Productivity (NPP), which is understood as the energy stored in the form of biomass by primary organisms through the process of photosynthesis and respiration. The variation of NPP by defined area produces changes in the properties of terrestrial and aquatic ecosystems, which alter factors such as biodiversity, nutrient cycling, carbon storage and water quality. The analysis of NPP to evaluate variations in ecosystem services includes harvested NPP (understood as provisioning services), which is the raw material from agricultural systems used by humans as a source of energy and food, and the remaining NPP (expressed as a regulating service) or the amount of biomass that remains in ecosystems after the harvesting process, which is mainly related to factors such as biodiversity. Given that agriculture is a fundamental pillar of Chile's integral development, the purpose of this study is to evaluate provisioning and regulating ecosystem services in the agricultural sector, specifically in cereal production, in the communes of the central-southern regions of Chile through a conceptual framework based on the quantification of the fraction of Human Appropriation of Net Primary Productivity (HANPP) and the fraction remaining in the ecosystems (NPP remaining). A total of 161 communes were analyzed in the regions of O'Higgins, Maule, Ñuble, Bio-Bío, La Araucanía and Los Lagos, which are characterized by having the largest areas planted with cereals. It was observed that the region of La Araucanía produces the greatest amount of dry matter, understood as provisioning service, where Victoria is the commune with the highest cereal production in the country. In addition, the maximum value of HANPP was in the O'Higgins region, highlighting the communes of Coltauco, Quinta de Tilcoco, Placilla and Rengo. On the other hand, the communes of Futrono, Pinto, Lago Ranco and Pemuco, whose cereal production was important during the study, had the highest values of remaining NPP as a regulating service. Finally, an inverse correlation was observed between the provisioning and regulating ecosystem services, i.e., the higher the cereal or dry matter production in a defined area, the lower the net primary production remaining in the ecosystems. Based on this study, future research will focus on the evaluation of ecosystem services associated with other crops, such as forestry plantations, whose activity is an important part of the country's productive sector.

Keywords: provisioning services, regulating services, net primary productivity, agriculture

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Authors: Yik Sin Chan, Bee Ling Chuah, Wei Quan Chan, Ri Jin Cheng, Yan Hang Oon, Kong Soo Khoo, Nam Weng Sit

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Traditionally, medicinal plants have been used to treat different kinds of ailments including infectious diseases. They serve as a good source of lead compounds for the development of new and safer anti-infective agents. This study aimed to investigate the antimicrobial potential of the leaves of three medicinal plants, namely Catunaregam spinosa (Rubiaceae; Mountain pomegranate), Houttuynia cordata (Saururaceae; "fishy-smell herb") and Rhapis excelsa (Arecaceae; “broadleaf lady palm”). The leaves extracts were obtained by sequential extraction using hexane, chloroform, ethyl acetate, ethanol, methanol and water. The antibacterial and antifungal activities were assessed using a colorimetric broth microdilution method against a panel of human pathogenic bacteria (Gram-positive: Bacillus cereus and Staphylococcus aureus; Gram-negative: Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa) and fungi (yeasts: Candida albicans, Candida parapsilosis and Cryptococcus neoformans; Moulds: Aspergillus fumigatus and Trichophyton mentagrophytes) respectively; while antiviral activity was evaluated against the Chikungunya virus on monkey kidney epithelial (Vero) cells by neutral red uptake assay. All the plant extracts showed bacteriostatic activity, however, only 72% of the extracts (13/18) were found to have bactericidal activity. The lowest minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were given by the hexane extract of C. spinosa against S. aureus with the values of 0.16 and 0.31 mg/mL respectively. All the extracts also possessed fungistatic activity. Only the hexane, chloroform and ethyl acetate extracts of H. cordata exerted inhibitory activity against A. fumigatus, giving the lowest fungal susceptibility index of 16.7%. In contrast, only 61% of the extracts (11/18) showed fungicidal activity. The ethanol extract of R. excelsa exhibited the strongest fungicidal activity against C. albicans, C. parapsilosis and T. mentagrophytes with minimum fungicidal concentration (MFC) values of 0.04–0.08 mg/mL, in addition to its methanol extract against T. mentagrophytes (MFC=0.02 mg/mL). For anti-Chikungunya virus activity, only chloroform and ethyl acetate extracts of R. excelsa showed significant antiviral activity with 50% effective concentrations (EC50) of 29.9 and 78.1 g/mL respectively. Extracts of R. excelsa warrant further investigations into their active principles responsible for antifungal and antiviral properties.

Keywords: bactericidal, Chikungunya virus, extraction, fungicidal

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Authors: Anna Wolowicz, Katarzyna Staszak, Zbigniew Hubicki

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Nowadays heavy metal ions as well as surfactants are widely used throughout the world due to their useful properties. The consequence of such widespread use is their significant production. On the other hand, the increasing demand for surfactants and heavy metal ions results in production of large amounts of wastewaters which are discharged to the environment from mining, metal plating, pharmaceutical, cosmetic, fertilizer, paper, pesticide and electronic industries, pigments producing, petroleum refining and from autocatalyst, fibers, food, polymer industries etc. Heavy metal ions are non-biodegradable in the environment, cable of accumulation in living organisms and organs, toxic and carcinogenic. On the other hand, not only heavy metal ions but also surfactants affect the purity of water and soils. Some of surfactants are also toxic, harmful and dangerous because they are able to penetrate into surface waters causing foaming, blocked diffusion of oxygen from the atmosphere and act as emulsifiers of hydrophobic substances and increase solubility of many the dangerous pollutants. Among surfactants the anionic ones dominate and their share in the global production of surfactants is around 50 ÷ 60%. Due to the negative impact of heavy metals and surfactants on aquatic ecosystems and living organisms, removal and monitoring of their concentration in the environment is extremely important. Surfactants and heavy metal ions removal can be achieved by different biological and physicochemical methods. The adsorption as well as the ion-exchange methods play here a significant role. The aim of this study was heavy metal ions removal from aqueous solutions using different types of ion exchangers in the presence of anionic surfactants. Preliminary studies of copper(II), nickel(II), zinc(II) and cobalt(II) removal from acidic solutions using ion exchangers (Lewatit MonoPlus TP 220, Lewatit MonoPlus SR 7, Purolite A 400 TL, Purolite A 830, Purolite S 984, Dowex PSR 2, Dowex PSR3, Lewatit AF-5) allowed to select the most effective ones for the above mentioned sorbates and then to checking their removal efficiency in the presence of anionic surfactants. As it was found out Lewatit MonoPlus TP 220 of the chelating type, show the highest sorption capacities for copper(II) ions in comparison with the other ion exchangers under discussion, e.g. 9.98 mg/g (0.1 M HCl); 9.12 mg/g (6 M HCl). Moreover, cobalt(II) removal efficiency was the highest in 0.1 M HCl using also Lewatit MonoPlus TP 220 (6.9 mg/g) similar to zinc(II) (9.1 mg/g) and nickiel(II) (6.2 mg/g). As the anionic surfactant sodium dodecyl sulphate (SDS) was used and surfactant parameters such as viscosity (η), density (ρ) and critical micelle concentration (CMC) were obtained: η = 1.13 ± 0,01 mPa·s; ρ = 999.76 mg/cm3; CMC = 2.26 g/cm3. The studies of copper(II) removal from acidic solutions in the presence of SDS of different concentration show negligible effects on copper(II) removal efficiency. The sorption capacity of Cu(II) from 0.1 M acidic solution of 500 mg/L initial concentration was equal to 46.8 mg/g whereas in the presence of SDS 45.3 mg/g (0.1 mg SDS/L), 47.1 mg/g (0.5 mg SDS/L), 46.6 mg/g (1 mg SDS/L).

Keywords: anionic surfactant, heavy metal ions, ion exchanger, removal

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Authors: Nivedhitha Venkatakrishnan

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Walking down busy temple streets in India is an experience in lifetime. Especially the temple streets are one of the most energetic places not only because of the divinity but also because of the streets itself which provides place for people to relax, meet, shop, linger, just walk around these activities create a set of experience which results in memories that lasts longer. Thinking of any temple street in India the image that comes to anyone’s mind are the elegantly sculpted Gopurams (Gateway) that depicts the craftsmanship and the history of the place, people taking a holy dip in the water, the aroma of the agarbathi’s, flowers with the divine Vedic chants and the sound of the temple bell flock of pigeons flying from the niches of the Gopuram with the sun in the backdrop. It gives a feeling of impulse energy that brings in life to these streets. Any temple street with even any one factor missing would look dead. This will be amiss in the essence in the scene of one’s experiences. These Temple Streets traditionally cater not only for religious purpose but to a wide range of activities. A vibrant street that facilitates such activities are preferred by the public any day. The research seeks to understand and find out the definition of Vibrancy in Indian Context. What is Vibrancy? What brings in the feeling of Vibrancy/Liveliness/Energy? Is it the Built structure and the city? Or is it the people? Or is it the Activity? Or is it Built structure – city – People – Activity put together brings the sense of Vibrancy to a place? How to define Vibrancy? Is it measurable? For which a case of Car Street Udupi, Karnataka is taken. The research is carried out in two stages. ‘Stage One’ makes use of ethnographic fieldwork as a basic method, complimented by structured field observations using a behavioral mapping procedure of the streets. Stage Two’ utilizes surveys that collected. This stage seeks to understand what design characteristics and furniture arrangements are associated with stationary, social and gathering activities of people by each cultural group and all groups collectively. The main conclusion from this research is that retail activities remain the main concern of people in cultural streets. Management and higher-level planning of retail activities on the streets could encourage and motivate possible Shops to enrich the trade variety of the street that provides a means for social and cultural diversity. In addition to business activities, spatial design characteristics are found to have an influence on people’s behavior and activity. The findings of this research suggest that retail and business activities, together with the design and skillful management of the public areas, could support a wider range of static and social activities among people of various ethnic backgrounds.

Keywords: activity, liveliness, temple street, vibrancy

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Authors: Sara R. Knigge, Sugat R. Tuladhar, Hans-Klaus HöFfler, Tobias Schilling, Tim Kaufeld, Axel Haverich

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Tissue engineered (TE) heart valves based on degradable electrospun fiber scaffold represent a promising approach to overcome the known limitations of mechanical or biological prostheses. But the mechanical stress in the high-pressure system of the human circulation is a severe challenge for the delicate materials. Hence, the prediction of the scaffolds` in vivo degradation kinetics must be as accurate as possible to prevent fatal events in future animal or even clinical trials. Therefore, this study investigates whether long-term testing in full blood provides more meaningful results regarding the degradation behavior than conventional tests in simulated body fluids (SBF) or Phosphate Buffered Saline (PBS). Fiber mats were produced from a polycaprolactone (PCL)/tetrafluoroethylene solution by electrospinning. The morphology of the fiber mats was characterized via scanning electron microscopy (SEM). A maximum physiological degradation environment utilizing a test set-up with porcine full blood was established. The set-up consists of a reaction vessel, an oxygenator unit, and a roller pump. The blood parameters (pO2, pCO2, temperature, and pH) were monitored with an online test system. All tests were also carried out in the test circuit with SBF and PBS to compare conventional degradation media with the novel full blood setting. The polymer's degradation is quantified by SEM picture analysis, differential scanning calorimetry (DSC), and Raman spectroscopy. Tensile and cyclic loading tests were performed to evaluate the mechanical integrity of the scaffold. Preliminary results indicate that PCL degraded slower in full blood than in SBF and PBS. The uptake of water is more pronounced in the full blood group. Also, PCL preserved its mechanical integrity longer when degraded in full blood. Protein absorption increased during the degradation process. Red blood cells, platelets, and their aggregates adhered on the PCL. Presumably, the degradation led to a more hydrophilic polymeric surface which promoted the protein adsorption and the blood cell adhesion. Testing degradable implants in full blood allows for developing more reliable scaffold materials in the future. Material tests in small and large animal trials thereby can be focused on testing candidates that have proven to function well in an in-vivo-like setting.

Keywords: Electrospun scaffold, full blood degradation test, long-term polymer degradation, tissue engineered aortic heart valve

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Authors: M. S. Stepanova, V. V. Zakharov, P. D. Khavlyuk, I. D. Skurlov, A. Y. Dubovik, A. L. Rogach

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Carbon dots are small carbon-based spherical nanoparticles, which are typically less than 10 nm in size that can be modified with surface passivation and heteroatoms doping. The light-absorbing ability of carbon dots has attracted a significant amount of attention in photoluminescence for bioimaging and fluorescence sensing applications owing to their advantages, such as tunable fluorescence emission, photo- and thermostability and low toxicity. In this study, carbon dots were synthesized by the solvothermal method from citric acid and ethylenediamine dissolved in water. The solution was heated for 5 hours at 200°C and then cooled down to room temperature. The carbon dots films were obtained by evaporation from a high-concentration aqueous solution. The increase of both luminescence intensity and light transmission was obtained as a result of a 405 nm laser exposure to a part of the carbon dots film, which was detected using a confocal laser scanning microscope (LSM 710, Zeiss). Blueshift up to 35 nm of the luminescence spectrum is observed as luminescence intensity, which is increased more than twofold. The exact value of the shift depends on the time of the laser exposure. This shift can be caused by the modification of surface groups at the carbon dots, which are responsible for long-wavelength luminescence. In addition, a shift of the absorption peak by 10 nm and a decrease in the optical density at the wavelength of 350 nm is detected, which is responsible for the absorption of surface groups. The obtained sample was also studied with time-resolved confocal fluorescence microscope (MicroTime 100, PicoQuant), which made it possible to receive a time-resolved photoluminescence image and construct emission decays of the laser-exposed and non-exposed areas. 5 MHz pulse rate impulse laser has been used as a photoluminescence excitation source. Photoluminescence decay was approximated by two exhibitors. The laser-exposed area has the amplitude of the first-lifetime component (A1) twice as much as before, with increasing τ1. At the same time, the second-lifetime component (A2) decreases. These changes evidence a modification of the surface groups of carbon dots. The detected effect can be used to create thermostable fluorescent marks, the physical size of which is bounded by the diffraction limit of the optics (~ 200-300 nm) used for exposure and to improve the optical properties of carbon dots or in the field of optical encryption. Acknowledgements: This work was supported by the Ministry of Science and Higher Education of Russian Federation, goszadanie no. 2019-1080 and financially supported by Government of Russian Federation, Grant 08-08.

Keywords: carbon dots, photoactivation, optical properties, photoluminescence and absorption spectra

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Authors: Ahmed Elsayed, Andrew Shea, Nicolas Kelly, John Allison

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In northern European climates, domestic space heating and hot water represents a significant proportion of total primary total primary energy use and meeting these demands from a national electricity grid network supplied by renewable energy sources provides an opportunity for a significant reduction in EU CO₂ emissions. However, in order to adapt to the intermittent nature of renewable energy generation and to avoid co-incident peak electricity usage from consumers that may exceed current capacity, the demand for heat must be decoupled from its generation. Storage of heat within the fabric of dwellings for use some hours, or days, later provides a route to complete decoupling of demand from supply and facilitates the greatly increased use of renewable energy generation into a local or national electricity network. The integration of thermal energy storage into the building fabric for retrieval at a later time requires much evaluation of the many competing thermal, physical, and practical considerations such as the profile and magnitude of heat demand, the duration of storage, charging and discharging rate, storage media, space allocation, etc. In this paper, the authors report investigations of thermal storage in building fabric using concrete material and present an evaluation of several factors that impact upon performance including heating pipe layout, heating fluid flow velocity, storage geometry, thermo-physical material properties, and also present an investigation of alternative storage materials and alternative heat transfer fluids. Reducing the heating pipe spacing from 200 mm to 100 mm enhances the stored energy by 25% and high-performance Vacuum Insulation results in heat loss flux of less than 3 W/m², compared to 22 W/m² for the more conventional EPS insulation. Dense concrete achieved the greatest storage capacity, relative to medium and light-weight alternatives, although a material thickness of 100 mm required more than 5 hours to charge fully. Layers of 25 mm and 50 mm thickness can be charged in 2 hours, or less, facilitating a fast response that could, aggregated across multiple dwellings, provide significant and valuable reduction in demand from grid-generated electricity in expected periods of high demand and potentially eliminate the need for additional new generating capacity from conventional sources such as gas, coal, or nuclear.

Keywords: fabric integrated thermal storage, FITS, demand side management, energy storage, load shifting, renewable energy integration

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Authors: Surekha Barkur, Aseefhali Bankapur, Santhosh Chidangil

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Raman Tweezers technique has become prevalent in single cell studies. This technique combines Raman spectroscopy which gives information about molecular vibrations, with optical tweezers which use a tightly focused laser beam for trapping the single cells. Thus Raman Tweezers enabled researchers analyze single cells and explore different applications. The applications of Raman Tweezers include studying blood cells, monitoring blood-related disorders, silver nanoparticle-induced stress, etc. There is increased interest in the toxic effect of nanoparticles with an increase in the various applications of nanoparticles. The interaction of these nanoparticles with the cells may vary with their size. We have studied the effect of silver nanoparticles of sizes 10nm, 40nm, and 100nm on erythrocytes using Raman Tweezers technique. Our aim was to investigate the size dependence of the nanoparticle effect on RBCs. We used 785nm laser (Starbright Diode Laser, Torsana Laser Tech, Denmark) for both trapping and Raman spectroscopic studies. 100 x oil immersion objectives with high numerical aperture (NA 1.3) is used to focus the laser beam into a sample cell. The back-scattered light is collected using the same microscope objective and focused into the spectrometer (Horiba Jobin Vyon iHR320 with 1200grooves/mm grating blazed at 750nm). Liquid nitrogen cooled CCD (Symphony CCD-1024x256-OPEN-1LS) was used for signal detection. Blood was drawn from healthy volunteers in vacutainer tubes and centrifuged to separate the blood components. 1.5 ml of silver nanoparticles was washed twice with distilled water leaving 0.1 ml silver nanoparticles in the bottom of the vial. The concentration of silver nanoparticles is 0.02mg/ml so the 0.03mg of nanoparticles will be present in the 0.1 ml nanoparticles obtained. The 25 ul of RBCs were diluted in 2 ml of PBS solution and then treated with 50 ul (0.015mg) of nanoparticles and incubated in CO2 incubator. Raman spectroscopic measurements were done after 24 hours and 48 hours of incubation. All the spectra were recorded with 10mW laser power (785nm diode laser), 60s of accumulation time and 2 accumulations. Major changes were observed in the peaks 565 cm-1, 1211 cm-1, 1224 cm-1, 1371 cm-1, 1638 cm-1. A decrease in intensity of 565 cm-1, increase in 1211 cm-1 with a reduction in 1224 cm-1, increase in intensity of 1371 cm-1 also peak disappearing at 1635 cm-1 indicates deoxygenation of hemoglobin. Nanoparticles with higher size were showing maximum spectral changes. Lesser changes observed in case of 10nm nanoparticle-treated erythrocyte spectra.

Keywords: erythrocytes, nanoparticle-induced toxicity, Raman tweezers, silver nanoparticles

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Authors: Sara Saboonian, Pierre Filion

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There are two distinct planning approaches attempting to transform the North American suburb so as to reduce its adverse environmental impacts. The first one, the recentralization approach, proposes intensification, multi-functionality and more reliance on public transit and walking. It thus offers an alternative to the prevailing low-density, spatial specialization and automobile dependence of the North American suburb. The second approach concentrates instead on the provision of green infrastructure, which rely on natural systems rather than on highly engineered solutions to deal with the infrastructure needs of suburban areas. There are tensions between these two approaches as recentralization generally overlooks green infrastructure, which can be space consuming (as in the case of water retention systems), and thus conflicts with the intensification goals of recentralization. The research investigates three Canadian planned suburban centres in the Greater Toronto Area, where recentralization is the current planning practice, despite rising awareness of the benefits of green infrastructure. Methods include reviewing the literature on green infrastructure planning, a critical analysis of the Ontario provincial plans for recentralization, surveying residents’ preferences regarding alternative suburban development models, and interviewing officials who deal with the local planning of the three centres. The case studies expose the difficulties in creating planned suburban centres that accommodate green infrastructure while adhering to recentralization principles. Until now, planners have been mostly focussed on recentralization at the expense of green infrastructure. In this context, the frequent lack of compatibility between recentralization and the space requirements of green infrastructure explains the limited presence of such infrastructures in planned suburban centres. Finally, while much attention has been given in the planning discourse to the economic and lifestyle benefits of recentralization, much less has been made of the wide range of advantages of green infrastructure, which explains limited public mobilization over the development of green infrastructure networks. The paper will concentrate on ways of combining recentralization with green infrastructure strategies and identify the aspects of the two approaches that are most compatible with each other. The outcome of such blending will marry high density, public-transit oriented developments, which generate walkability and street-level animation, with the presence of green space, naturalized settings and reliance on renewable energy. The paper will advance a planning framework that will fuse green infrastructure with recentralization, thus ensuring the achievement of higher density and reduced reliance on the car along with the provision of critical ecosystem services throughout cities. This will support and enhance the objectives of both green infrastructure and recentralization.

Keywords: environmental-based planning, green infrastructure, multi-functionality, recentralization

Procedia PDF Downloads 131

Authors: Michalina Aniola, Andrzej Katrusiak

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4,4-Bipyridine is an important compound often used in chemical practice and more recently frequently applied for designing new metal organic framework (MoFs). Here we present a systematic high-pressure study of its hydrobromide salt. 4,4-Bipyridine hydrobromide monohydrate, 44biPyHBrH₂O, at ambient-pressure is orthorhombic, space group P212121 (phase a). Its hydrostatic compression shows that it is stable to 1.32 GPa at least. However, the recrystallization above 0.55 GPa reveals a new hidden b-phase (monoclinic, P21/c). Moreover, when the 44biPyHBrH2O is heated to high temperature the chemical reactions of this compound in methanol solution can be observed. High-pressure experiments were performed using a Merrill-Bassett diamond-anvil cell (DAC), modified by mounting the anvils directly on the steel supports, and X-ray diffraction measurements were carried out on a KUMA and Excalibur diffractometer equipped with an EOS CCD detector. At elevated pressure, the crystal of 44biPyHBrH₂O exhibits several striking and unexpected features. No signs of instability of phase a were detected to 1.32 GPa, while phase b becomes stable at above 0.55 GPa, as evidenced by its recrystallizations. Phases a and b of 44biPyHBrH2O are partly isostructural: their unit-cell dimensions and the arrangement of ions and water molecules are similar. In phase b the HOH-Br- chains double the frequency of their zigzag motifs, compared to phase a, and the 44biPyH+ cations change their conformation. Like in all monosalts of 44biPy determined so far, in phase a the pyridine rings are twisted by about 30 degrees about bond C4-C4 and in phase b they assume energy-unfavorable planar conformation. Another unusual feature of 44biPyHBrH2O is that all unit-cell parameters become longer on the transition from phase a to phase b. Thus the volume drop on the transition to high-pressure phase b totally depends on the shear strain of the lattice. Higher temperature triggers chemical reactions of 44biPyHBrH2O with methanol. When the saturated methanol solution compound precipitated at 0.1 GPa and temperature of 423 K was required to dissolve all the sample, the subsequent slow recrystallization at isochoric conditions resulted in disalt 4,4-bipyridinium dibromide. For the 44biPyHBrH2O sample sealed in the DAC at 0.35 GPa, then dissolved at isochoric conditions at 473 K and recrystallized by slow controlled cooling, a reaction of N,N-dimethylation took place. It is characteristic that in both high-pressure reactions of 44biPyHBrH₂O the unsolvated disalt products were formed and that free base 44biPy and H₂O remained in the solution. The observed reactions indicate that high pressure destabilized ambient-pressure salts and favors new products. Further studies on pressure-induced reactions are carried out in order to better understand the structural preferences induced by pressure.

Keywords: conformation, high-pressure, negative area compressibility, polymorphism

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Authors: Prajakta Khare

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There is a huge number of social enterprises operating in India, across all enterprise sizes and forms addressing diverse social issues. Some cases such as such as Aravind eye care, Narayana Hridalaya, SEWA have been studied extensively in management literature and are known cases in social entrepreneurship. But there are several smaller social enterprises in India that are not called so per se due to the lack of understanding of the concept. There is a lack of academic research on social entrepreneurship in India and the term ‘social entrepreneurship’ is not yet widely known in the country, even by people working in this field as was found by this study. The present study aims to identify the most prominent form of social enterprises in India, the profile of the entrepreneurs, challenges faced, the lessons (theory and practices) emerging from their functioning and finally the factors contributing to the enterprises’ success. This is a preliminary exploratory study using primary data from 30 social enterprises in India. The study used snow ball sampling and a qualitative analysis. Data was collected from founders of social enterprises through written structured questionnaires, open-ended interviews and field visits to enterprises. The sample covered enterprises across sectors such as environment, affordable education, children’s rights, rain water harvesting, women empowerment etc. The interview questions focused on founder’s background and motivation, qualifications, funding, challenges, founder’s understanding and perspectives on social entrepreneurship, government support, linkages with other organizations etc. apart from several others. The interviews were conducted across 3 languages - Hindi, Marathi, English and were then translated and transcribed. 50% of founders were women and 65% of the total founders were highly qualified with a MBA, PhD or MBBS. The most important challenge faced by these entrepreneurs is recruiting skilled people. When asked about their understanding of the term, founders had diverse perspectives. Also, their understandings about the term social enterprise and social entrepreneur were extremely varied. Some founders identified the terms with doing something good for the society, some thought that every business can be called a social enterprise. 35% of the founders were not aware of the term social entrepreneur/ social entrepreneurship. They said that they could identify themselves as social entrepreneurs after discussions with the researcher. The general perception in India is that ‘NGOs are corrupt’- fighting against this perception to secure funds is also another problem as pointed out by some founders. There are unique challenges that social entrepreneurs in India face, as the political, social, economic environment around them is rapidly changing; and getting adequate support from the government is a problem. The research in its subsequent stages aims to clarify existing, missing and new definitions of the term to provide deeper insights in the terminology and issues relating to Social Entrepreneurship in India.

Keywords: challenges, India, social entrepreneurship, social entrepreneurs

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Authors: Sylvain Perrin, Thomas Saillour

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The Grande-Motte port and seafront development project on the French Mediterranean coastline entailed evaluating wave impact loads (pressures and forces) on the new beach seawall and comparing the resulting scour potential at the base of the existing and new seawall. A physical model was built at ARTELIA’s hydraulics laboratory in Grenoble (France) to provide insight into the evolution of scouring overtime at the front of the wall, quasi-static and impulsive wave force intensity and distribution on the wall, and water and sand overtopping discharges over the wall. The beach was constituted of fine sand and approximately 50 m wide above mean sea level (MSL). Seabed slopes were in the range of 0.5% offshore to 1.5% closer to the beach. A smooth concrete structure will replace the existing concrete seawall with an elevated curved crown wall. Prior the start of breaking (at -7 m MSL contour), storm-driven maximum spectral significant wave heights of 2.8 m and 3.2 m were estimated for the benchmark historical storm event dated of 1997 and the 50-year return period storms respectively, resulting in 1 m high waves at the beach. For the wave load assessment, a tensor scale measured wave forces and moments and five piezo / piezo-resistive pressure sensors were placed on the wall. Light-weight sediment physical model and pressure and force measurements were performed with scale 1:18. The polyvinyl chloride light-weight particles used to model the prototype silty sand had a density of approximately 1 400 kg/m3 and a median diameter (d50) of 0.3 mm. Quantitative assessments of the seabed evolution were made using a measuring rod and also a laser scan survey. Testing demonstrated the occurrence of numerous impulsive wave impacts on the reflector (22%), induced not by direct wave breaking but mostly by wave run-up slamming on the top curved part of the wall. Wave forces of up to 264 kilonewtons and impulsive pressure spikes of up to 127 kilonewtons were measured. Maximum scour of -0.9 m was measured for the new seawall versus -0.6 m for the existing seawall, which is imputable to increased wave reflection (coefficient was 25.7 - 30.4% vs 23.4 - 28.6%). This paper presents a methodology for the setup and operation of a physical model in order to assess the hydrodynamic and morphodynamic processes at a beach seawall during storms events. It discusses the pros and cons of such methodology versus others, notably regarding structures peculiarities and model effects.

Keywords: beach, impacts, scour, seawall, waves

Procedia PDF Downloads 153

Authors: Ying-Chang Yu, Yuan-Lung Lo

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Building envelope design is one of the most popular design fields of architectural profession in nowadays. The main design trend of such system is to highlight the designer's aesthetic intention from the outlook of building project. Due to the trend of current façade design, the building envelope contains more and more layers of components, such as double skin façade, photovoltaic panels, solar control system, or even ornamental components. These exterior components are designed for various functional purposes. Most researchers focus on how these exterior elements should be structurally sound secured. However, not many researchers consider these elements would help to improve the performance of façade system. When the exterior elements are deployed in large scale, it creates an additional layer outside of original façade system and acts like a porous interface which would interfere with the aerodynamic of façade surface in micro-scale. A standard façade performance consists with 'water penetration, air infiltration rate, operation force, and component deflection ratio', and these key performances are majorly driven by the 'Design Wind Load' coded in local regulation. A design wind load is usually determined by the maximum wind pressure which occurs on the surface due to the geometry or location of building in extreme conditions. This research was designed to identify the air damping phenomenon of micro turbulence caused by porous exterior layer leading to surface wind load reduction for improvement of façade system performance. A series of wind tunnel test on dynamic pressure sensor array covered by various scale of porous exterior skin was conducted to verify the effect of wind pressure reduction. The testing specimens were designed to simulate the typical building with two-meter extension offsetting from building surface. Multiple porous exterior skins were prepared to replicate various opening ratio of surface which may cause different level of damping effect. This research adopted 'Pitot static tube', 'Thermal anemometers', and 'Hot film probe' to collect the data of surface dynamic pressure behind porous skin. Turbulence and distributed resistance are the two main factors of aerodynamic which would reduce the actual wind pressure. From initiative observation, the reading of surface wind pressure was effectively reduced behind porous media. In such case, an actual building envelope system may be benefited by porous skin from the reduction of surface wind pressure, which may improve the performance of envelope system consequently.

Keywords: multi-layer facade, porous media, facade performance, turbulence and distributed resistance, wind tunnel test

Procedia PDF Downloads 217

Authors: Anne C. Richer-De-Forges, Dominique Arrouays, Songchao Chen, Mercedes Roman Dobarco

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Most of the digital soil mapping (DSM) products rely on machine learning (ML) prediction models and/or the use or pedotransfer functions (PTF) in which calibration data come from soil analyses performed in labs. However, many other observations (often qualitative, nominal, or ordinal) could be used as proxies of lab measurements or as input data for ML of PTF predictions. DSM and ML are briefly described with some examples taken from the literature. Then, we explore the potential of an ordinal qualitative variable, i.e., the hand-feel soil texture (HFST) estimating the mineral particle distribution (PSD): % of clay (0-2µm), silt (2-50µm) and sand (50-2000µm) in 15 classes. The PSD can also be measured by lab measurements (LAST) to determine the exact proportion of these particle-sizes. However, due to cost constraints, HFST are much more numerous and spatially dense than LAST. Soil texture (ST) is a very important soil parameter to map as it is controlling many of the soil properties and functions. Therefore, comes an essential question: is it possible to use HFST as a proxy of LAST for calibration and/or validation of DSM predictions of ST? To answer this question, the first step is to compare HFST with LAST on a representative set where both information are available. This comparison was made on ca 17,400 samples representative of a French region (34,000 km2). The accuracy of HFST was assessed, and each HFST class was characterized by a probability distribution function (PDF) of its LAST values. This enables to randomly replace HFST observations by LAST values while respecting the PDF previously calculated and results in a very large increase of observations available for the calibration or validation of PTF and ML predictions. Some preliminary results are shown. First, the comparison between HFST classes and LAST analyses showed that accuracies could be considered very good when compared to other studies. The causes of some inconsistencies were explored and most of them were well explained by other soil characteristics. Then we show some examples applying these relationships and the increase of data to several issues related to DSM. The first issue is: do the PDF functions that were established enable to use HSFT class observations to improve the LAST soil texture prediction? For this objective, we replaced all HFST for topsoil by values from the PDF 100 time replicates). Results were promising for the PTF we tested (a PTF predicting soil water holding capacity). For the question related to the ML prediction of LAST soil texture on the region, we did the same kind of replacement, but we implemented a 10-fold cross-validation using points where we had LAST values. We obtained only preliminary results but they were rather promising. Then we show another example illustrating the potential of using HFST as validation data. As in numerous countries, the HFST observations are very numerous; these promising results pave the way to an important improvement of DSM products in all the countries of the world.

Keywords: digital soil mapping, improvement of digital soil mapping predictions, potential of using hand-feel soil texture, soil texture prediction

Procedia PDF Downloads 223

Authors: Anderson Braga Mendes

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Itaipu Hydroelectric Power Plant is settled on the Paraná River, which is a natural boundary between Brazil and Paraguay; thus, the facility is shared by both countries. Itaipu Power Plant is the biggest hydroelectric generator in the world, and provides clean and renewable electrical energy supply for 17% and 76% of Brazil and Paraguay, respectively. The plant started its generation in 1984. It counts on 20 Francis turbines and has installed capacity of 14,000 MWh. Its historic generation record occurred in 2016 (103,098,366 MWh), and since the beginning of its operation until the last day of 2016 the plant has achieved the sum of 2,415,789,823 MWh. The distinct sedimentologic aspects of the drainage area of Itaipu Power Plant, from its stretch upstream (Porto Primavera and Rosana dams) to downstream (Itaipu dam itself), were taken into account in order to best estimate the increase/decrease in the sediment yield by using data from 2001 to 2016. Such data are collected through a network of 14 automatic sedimentometric stations managed by the company itself and operating in an hourly basis, covering an area of around 136,000 km² (92% of the incremental drainage area of the undertaking). Since 1972, a series of lifespan studies for the Itaipu Power Plant have been made, being first assessed by Sir Hans Albert Einstein, at the time of the feasibility studies for the enterprise. From that date onwards, eight further studies were made through the last 44 years aiming to confer more precision upon the estimates based on more updated data sets. From the analysis of each monitoring station, it was clearly noticed strong increase tendencies in the sediment yield through the last 14 years, mainly in the Iguatemi, Ivaí, São Francisco Falso and Carapá Rivers, the latter situated in Paraguay, whereas the others are utterly in Brazilian territory. Five lifespan scenarios considering different sediment yield tendencies were simulated with the aid of the softwares SEDIMENT and DPOSIT, both developed by the author of the present work. Such softwares thoroughly follow the Borland & Miller methodology (empirical method of area-reduction). The soundest scenario out of the five ones under analysis indicated a lifespan foresight of 168 years, being the reservoir only 1.8% silted by the end of 2016, after 32 years of operation. Besides, the mass balance in the reservoir (water inflows minus outflows) between 1986 and 2016 shows that 2% of the whole Itaipu lake is silted nowadays. Owing to the convergence of both results, which were acquired by using different methodologies and independent input data, it is worth concluding that the mathematical modeling is satisfactory and calibrated, thus assigning credibility to this most recent lifespan estimate.

Keywords: Borland and Miller method, hydroelectricity, Itaipu Power Plant, lifespan, mass balance

Procedia PDF Downloads 274

Authors: Asmamaw Yehun

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The name “TANA” is one of International Geodetic Service (IGS) Global Positioning System (GPS) station which is found in Bahir Dar University in Institute of Land Administration. The station name taken from one of big Lakes in Africa ,Lake Tana. The Institute of Land Administration (ILA) is part of Bahir Dar University, located in the capital of the Amhara National Regional State, Bahir Dar. The institute is the first of its kind in East Africa. The station is installed by cooperation of ILA and Sweden International Development Agency (SIDA) fund support. The Continues Operating Reference Station (CORS) is a network of stations that provide global satellite system navigation data to help three dimensional positioning, meteorology, space, weather, and geophysical applications throughout the globe. TANA station was as CORS since 2013 and sites are independently owned and operated by governments, research and education facilities and others. The data collected by the reference station is downloadable through Internet for post processing purpose by interested parties who carry out GNSS measurements and want to achieve a higher accuracy. We made a first observation on TANA, monitor stations on May 29th 2013. We used Leica 1200 receivers and AX1202GG antennas and made observations from 11:30 until 15:20 for about 3h 50minutes. Processing of data was done in an automatic post processing service CSRS-PPP by Natural Resources Canada (NRCan) . Post processing was done June 27th 2013 so precise ephemeris was used 30 days after observation. We found Latitude (ITRF08): 11 34 08.6573 (dms) / 0.008 (m), Longitude (ITRF08): 37 19 44.7811 (dms) / 0.018 (m) and Ellipsoidal Height (ITRF08): 1850.958 (m) / 0.037 (m). We were compared this result with GAMIT/GLOBK processed data and it was very closed and accurate. TANA station is one of the second IGS station for Ethiopia since 2015 up to now. It provides data for any civilian users, researchers, governmental and nongovernmental users. TANA station is installed with very advanced choke ring antenna and GR25 Leica receiver and also the site is very good for satellite accessibility. In order to test hydrostatic and wet zenith delay for positional data quality, we used GAMIT/GLOBK and we found that TANA station is the most accurate IGS station in East Africa. Due to lower tropospheric zenith and ionospheric delay, TANA and ADIS IGS stations has 2 and 1.9 meters 3D positional accuracy respectively.

Keywords: atmosphere, GNSS, neutral atmosphere, precipitable water vapour

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Authors: Toslim Uddin Khan, Jesmin Akter, Mohiuddin Ahmed

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Menstrual hygiene management (MHM) and personal health-care practice is a critical issue to prevent morbidity and other reproductive health complications among adolescent girls in Bangladesh. Inadequate access to water, sanitation and hygiene (WASH) facilities lead to unhealthy MHM practices that resulted in poor reproductive health outcomes. It is evident from different studies that superstitions and misconception are more common in rural communities that limit young girls’ access to and understanding of the menstrual hygiene and self care practices. The state-of-the-art approach of Social Marketing Company (SMC) is proved to be instrumental in delivering reinforcing health messages, making public health and hygiene products available at the door steps of the community through community mobilization programs in rural Bangladesh. School health program is one of the flagship interventions of SMC to equip adolescent girls and boys with correct knowledge of health and hygiene practices among themselves, their families and peers. In Bangladeshi culture, adolescent girls often feel shy to ask fathers or male family members about buying sanitary napkin from local pharmacy and they seem to be reluctant to seek help regarding their menstrual problems. A recent study reveals that 48% adolescent girls are using sanitary napkins while majority of them are unaware of menstrual hygiene practices in Bangladesh. Under school adolescent program, SMC organizes health education sessions for adolescent girls from grade seven to ten using enter-educate approach with special focus on sexual and reproductive health and menstrual hygiene issues including delaying marriage and first pregnancy. In addition, 2500 rural women entrepreneurs branded as community sales agents are also involved in disseminating health messages and selling priority health products including sanitary napkin at the household level. These women entrepreneurs are serving as a source of sustainable supply of the sanitary napkins for the rural adolescent girls and thereby they are earning profit margins on the sales they make. A recent study on the impact of adolescent program activities reveals that majority (71%) of the school adolescent girls are currently using sanitary napkins. Health education equips and empowers adolescent girls with accurate knowledge about menstrual hygiene practices and self-care as well. Therefore, engagement of female entrepreneurs in school adolescent health program at the community level is one of the promising ways to improve menstrual hygiene practices leading to increased use of sanitary napkin in rural and semi-rural communities in Bangladesh.

Keywords: school adolescent program, social marketing, women entrepreneurs, menstrual hygiene management

Procedia PDF Downloads 197

Authors: Anuruddha Jayasuriya, Thanakorn Pheeraphan

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In this paper, a review of different mathematical models which can be used as prediction tools to assess the time to crack reinforced concrete (RC) due to corrosion is investigated. This investigation leads to an experimental study to validate a selected prediction model. Most of these mathematical models depend upon the mechanical behaviors, chemical behaviors, electrochemical behaviors or geometric aspects of the RC members during a corrosion process. The experimental program is designed to verify the accuracy of a well-selected mathematical model from a rigorous literature study. Fundamentally, the experimental program exemplifies both one-dimensional chloride diffusion using RC squared slab elements of 500 mm by 500 mm and two-dimensional chloride diffusion using RC squared column elements of 225 mm by 225 mm by 500 mm. Each set consists of three water-to-cement ratios (w/c); 0.4, 0.5, 0.6 and two cover depths; 25 mm and 50 mm. 12 mm bars are used for column elements and 16 mm bars are used for slab elements. All the samples are subjected to accelerated chloride corrosion in a chloride bath of 5% (w/w) sodium chloride (NaCl) solution. Based on a pre-screening of different models, it is clear that the well-selected mathematical model had included mechanical properties, chemical and electrochemical properties, nature of corrosion whether it is accelerated or natural, and the amount of porous area that rust products can accommodate before exerting expansive pressure on the surrounding concrete. The experimental results have shown that the selected model for both one-dimensional and two-dimensional chloride diffusion had ±20% and ±10% respective accuracies compared to the experimental output. The half-cell potential readings are also used to see the corrosion probability, and experimental results have shown that the mass loss is proportional to the negative half-cell potential readings that are obtained. Additionally, a statistical analysis is carried out in order to determine the most influential factor that affects the time to corrode the reinforcement in the concrete due to chloride diffusion. The factors considered for this analysis are w/c, bar diameter, and cover depth. The analysis is accomplished by using Minitab statistical software, and it showed that cover depth is the significant effect on the time to crack the concrete from chloride induced corrosion than other factors considered. Thus, the time predictions can be illustrated through the selected mathematical model as it covers a wide range of factors affecting the corrosion process, and it can be used to predetermine the durability concern of RC structures that are vulnerable to chloride exposure. And eventually, it is further concluded that cover thickness plays a vital role in durability in terms of chloride diffusion.

Keywords: accelerated corrosion, chloride diffusion, corrosion cracks, passivation layer, reinforcement corrosion

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Authors: D. Falliano, G. Ricciardi, E. Gugliandolo

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Foamed concrete belongs to the category of lightweight concrete. It is characterized by a density which is generally ranging from 200 to 2000 kg/m³ and typically comprises cement, water, preformed foam, fine sand and eventually fine particles such as fly ash or silica fume. The foam component mixed with the cement paste give rise to the development of a system of air-voids in the cementitious matrix. The peculiar characteristics of foamed concrete elements are summarized in the following aspects: 1) lightness which allows reducing the dimensions of the resisting frame structure and is advantageous in the scope of refurbishment or seismic retrofitting in seismically vulnerable areas; 2) thermal insulating properties, especially in the case of low densities; 3) the good resistance against fire as compared to ordinary concrete; 4) the improved workability; 5) cost-effectiveness due to the usage of rather simple constituting elements that are easily available locally. Classic foamed concrete cannot be extruded, as the dimensional stability is not permitted in the green state and this severely limits the possibility of industrializing them through a simple and cost-effective process, characterized by flexibility and high production capacity. In fact, viscosity enhancing agents (VEA) used to extrude traditional concrete, in the case of foamed concrete cause the collapsing of air bubbles, so that it is impossible to extrude a lightweight product. These requirements have suggested the study of a particular additive that modifies the rheology of foamed concrete fresh paste by increasing cohesion and viscosity and, at the same time, stabilizes the bubbles into the cementitious matrix, in order to allow the dimensional stability in the green state and, consequently, the extrusion of a lightweight product. There are plans to submit the additive’s formulation to patent. In addition to the general benefits of using the extrusion process, extrudable foamed concrete allow other limits to be exceeded: elimination of formworks, expanded application spectrum, due to the possibility of extrusion in a range varying between 200 and 2000 kg/m³, which allows the prefabrication of both structural and non-structural constructive elements. Besides, this contribution aims to present the significant differences regarding extrudable and classic foamed concrete fresh properties in terms of slump. Plastic air content, plastic density, hardened density and compressive strength have been also evaluated. The outcomes show that there are no substantial differences between extrudable and classic foamed concrete compression resistances.

Keywords: compressive strength, extrusion, foamed concrete, fresh properties, plastic air content, slump.

Procedia PDF Downloads 174

Authors: Aaron Liggett

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This research focuses on the visionary proposal made by the Olmsted Brothers Landscape Architecture firm in the 1920s for a network of interconnected parkways in Los Angeles. Their envisioned parkways aimed to address environmental and cultural strains by providing green space for recreation, wildlife habitat, and stormwater management while serving as multimodal transportation routes. Although the parkways were never constructed, through an evidence-based approach, this research presents a framework for evaluating the potential functionality and success of the parkways by modeling and visualizing their quantitative and qualitative landscape performance and benefits. Historical documents and innovative digital modeling tools produce detailed analysis, modeling, and visualization of the parkway designs. A set of 1928 construction documents are used to analyze and interpret the design intent of the parkways. Grading plans are digitized in CAD and modeled in Sketchup to produce 3D visualizations of the parkway. Drainage plans are digitized to model stormwater performance. Planting plans are analyzed to model urban forestry and biodiversity. The EPA's Storm Water Management Model (SWMM) predicts runoff quantity and quality. The USDA Forests Service tools evaluate carbon sequestration and air quality. Spatial and overlay analysis techniques are employed to assess urban connectivity and the spatial impacts of the parkway designs. The study reveals how the integration of blue infrastructure, green infrastructure, and transportation infrastructure within the parkway design creates a multifunctional landscape capable of offering alternative spatial and temporal uses. The analysis demonstrates the potential for multiple functional, ecological, aesthetic, and social benefits to be derived from the proposed parkways. The analysis of the Olmsted Brothers' proposed Los Angeles parkways, which predated contemporary ecological design and resiliency practices, demonstrates the potential for providing multiple functional, ecological, aesthetic, and social benefits within urban designs. The findings highlight the importance of integrated blue, green, and transportation infrastructure in creating a multifunctional landscape that simultaneously serves multiple purposes. The research contributes new methods for modeling and visualizing landscape performance benefits, providing insights and techniques for informing future designs and sustainable development strategies.

Keywords: landscape architecture, ecological urban design, greenway, landscape performance

Procedia PDF Downloads 130

Authors: Noureddine Ben Ayed, Abdelkader Soumaya, Saïd Maouche, Ali Kadri, Mongi Gueddiche, Hayet Khayati-Ammar, Ahmed Braham

Abstract:

The archaeological monument of Utica, located in north-eastern Tunisia, was founded (8th century BC) By the Phoenicians as a port installed on the trade route connecting Phoenicia and the Straits of Gibraltar in the Mediterranean Sea. The flourishment of this city as an important settlement during the Roman period was followed by a sudden abandonment, disuse and progressive oblivion in the first half of the fifth century AD. This decadence can be attributed to the destructive earthquake of 5 July 408 - 410 AD, affecting this historic city as documented in 1906 by the seismologist Fernand De Montessus De Ballore. The magnitude of the Utica earthquake was estimated at 6.8 by the Tunisian National Institute of Meteorology (INM). In order to highlight the damage caused by this earthquake, a field survey was carried out at the Utica ruins to detect and analyse the earthquake archaeological effects (EAEs) using structural geology methods. This approach allowed us to highlight several structural damages, including: (1) folded mortar pavements, (2) cracks affecting the mosaic and walls of a water basin in the "House of the Grand Oecus", (3) displaced columns, (4) block extrusion in masonry walls, (5) undulations in mosaic pavements, (6) tilted walls. The structural analysis of these EAEs and data measurements reveal a seismic cause for all evidence of deformation in the Utica monument. The maximum horizontal strain of the ground (e.g. SHmax) inferred from the building oriented damage in Utica shows a NNW-SSE direction under a compressive tectonic regime. For the seismogenic source of this earthquake, we propose the active E-W to NE-SW trending Utique - Ghar El Melh reverse fault, passing through the Utica Monument and extending towards the Ghar El Melh Lake, as the causative tectonic structure. The active fault trace is well supported by instrumental seismicity, geophysical data (e.g., gravity, seismic profiles) and geomorphological analyses. In summary, we find that the archaeoseismic records detected at Utica are similar to those observed at many other archaeological sites affected by destructive ancient earthquakes around the world. Furthermore, the calculated orientation of the average maximum horizontal stress (SHmax) closely match the state of the actual stress field, as highlighted by some earthquake focal mechanisms in this region.

Keywords: Tunisia, utica, seimogenic fault, archaeological earthquake effects

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Authors: Isidro Perez, Maryam Nazari

Abstract:

Numerous earthquakes, which have taken place across the world, led to catastrophic damage and collapse of structures (e.g., 1971 San Fernando; 1995 Kobe-Japan; and 2010 Chile earthquakes). Engineers are constantly studying methods to moderate the effect this phenomenon has on structures to further reduce damage, costs, and ultimately to provide life safety to occupants. However, there are regions where structures, cities, or water reservoirs are built near fault lines. When an earthquake occurs near the fault lines, they can be categorized as near-field earthquakes. In contrary, a far-field earthquake occurs when the region is further away from the seismic source. A near-field earthquake generally has a higher initial peak resulting in a larger seismic response, when compared to a far-field earthquake ground motion. These larger responses may result in serious consequences in terms of structural damage which can result in a high risk for the public’s safety. Unfortunately, the response of structures subjected to near-field records are not properly reflected in the current building design specifications. For example, in ASCE 7-10, the design response spectrum is mostly based on the far-field design-level earthquakes. This may result in the catastrophic damage of structures that are not properly designed for near-field earthquakes. This research investigates the knowledge that the effect of near-field earthquakes has on the response of structures. To fully examine this topic, a structure was designed following the current seismic building design specifications, e.g. ASCE 7-10 and ACI 318-14, being analytically modeled, utilizing the SAP2000 software. Next, utilizing the FEMA P695 report, several near-field and far-field earthquakes were selected, and the near-field earthquake records were scaled to represent the design-level ground motions. Upon doing this, the prototype structural model, created using SAP2000, was subjected to the scaled ground motions. A Linear Time History Analysis and Pushover analysis were conducted on SAP2000 for evaluation of the structural seismic responses. On average, the structure experienced an 8% and 1% increase in story drift and absolute acceleration, respectively, when subjected to the near-field earthquake ground motions. The pushover analysis was ran to find and aid in properly defining the hinge formation in the structure when conducting the nonlinear time history analysis. A near-field ground motion is characterized by a high-energy pulse, making it unique to other earthquake ground motions. Therefore, pulse extraction methods were used in this research to estimate the maximum response of structures subjected to near-field motions. The results will be utilized in the generation of a design spectrum for the estimation of design forces for buildings subjected to NF ground motions.

Keywords: near-field, pulse, pushover, time-history

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Authors: Kirsi Laurén, Tiina Seppä

Abstract:

This study focuses on human-mire relations in the context of digital aestheticization and the long-standing tradition of folklore concerning mires. The study concentrates on the Patvinsuo mire in Eastern Finland and the Viiankiaapa mire in Finnish Lapland. Patvinsuo is a national park, and Viiankiaapa is a protected mire area with hiking trails and other recreational infrastructure. Perceiving the environment through digital technology can help to notice aesthetic details in nature. In addition, sharing images and texts digitally through social media adds a sense of community to the relationship with nature and, at the same time, creates a different kind of living heritage where old and new traditions meet and mingle. People visiting and camping in these areas 'self-care' themselves through recreation in nature. However, these practices and digital aestheticization can sometimes lead to the erosion of fragile mires. The research focuses on understanding the impact of digital aestheticization, such as taking digital photos, on the relationship with nature for individuals moving and working in mires. Additionally, the study aims to explore the contemporary perception of the water environment in mires and its cultural heritage, including mythical and folkloric elements. The research material consists of senso-digital walking interviews and digital recordings (audio recordings, photographs, videos) made during the mire walks, as well as archival material from the Finnish Literature Society’s Archives on mire folklore. The analysis of the material relies centrally on theories from sensory anthropology on the relationship between sensory perception and culture. The modern-day interviewees include outdoor enthusiasts spending their leisure time in mires, artists treating mires in their art, and nature experts (scientists, civil servants, and nature guides). The senso-digital walking interviews were conducted in Patvinsuo and Viiankiaapa mires on a trail chosen by the interviewees themselves. The material selected from the archive consists mainly of folk beliefs and folk poetry from the 19th and 20th centuries that express the relationship of the narrator to the mires. The interview and archival materials date from different periods and are different in character, which has to be taken into account in the analysis. However, in the analysis of both materials, particular attention is paid to the descriptions of sensations that appear in them. Analyzing the materials in parallel is limited by the fact that they date from different periods, but on the other hand, it is their different ages that make it possible to perceive the changes in the cultural heritage of mires.

Keywords: mires, living heritage, digital aestheticization, folklore, sensory anthropology

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Authors: Saddam Hussain, Ghadeer Mohsen Albadrani

Abstract:

Pakistan is one of the most vulnerable countries to climate change. Being a country where 23% of the country’s GDP relies on agriculture, this is a serious cause of concern. Introducing industrial hemp in Pakistan can help build climate resilience in the agricultural sector of the country, as hemp has recently emerged as a sustainable, eco-friendly, resource-efficient, and climate-resilient crop globally. Hemp has the potential to absorb huge amounts of CO₂, nourish the soil, and be used to create various biodegradable and eco-friendly products. Hemp is twice as effective as trees at absorbing and locking up carbon, with 1 hectare (2.5 acres) of hemp reckoned to absorb 8 to 22 tonnes of CO₂ a year, more than any woodland. Along with its high carbon-sequestration ability, it produces higher biomass and can be successfully grown as a cover crop. Hemp can grow in almost all soil conditions and does not require pesticides. It has fast-growing qualities and needs only 120 days to be ready for harvest. Compared with cotton, hemp requires 50% less water to grow and can produce three times higher fiber yield with a lower ecological footprint. Recently, the Government of Pakistan has allowed the cultivation of industrial hemp for industrial and medicinal purposes, making it possible for hemp to be reinserted into the country’s economy. Pakistan’s agro-climatic and edaphic conditions are well-suitable to produce industrial hemp, and its cultivation can bring economic benefits to the country. Pakistan can enter global markets as a new exporter of hemp products. The production of hemp in Pakistan can be most exciting to the workforce, especially for farmers participating in hemp markets. The minimum production cost of hemp makes it affordable to small holding farmers, especially those who need their cropping system to be as highly sustainable as possible. Dr. Saddam Hussain is leading the first pilot project of Industrial Hemp in Pakistan. In the past three years, he has been able to recruit high-impact research grants on industrial hemp as Principal Investigator. He has already screened the non-toxic hemp genotypes, tested the adaptability of exotic material in various agroecological conditions, formulated the production agronomy, and successfully developed the complete value chain. He has developed prototypes (fabric, denim, knitwear) using hemp fibre in collaboration with industrial partners and has optimized the indigenous fibre processing techniques. In this lecture, Dr. Hussain will talk on hemp agronomy and its complete fibre value chain. He will discuss the current progress, and will highlight the major challenges and future research direction on hemp research.

Keywords: industrial hemp, agricultural sustainability, agronomic evaluation, hemp value chain

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