Search results for: temperature dependent materials
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 14618

Search results for: temperature dependent materials

2978 Integrating Non-Psychoactive Phytocannabinoids and Their Cyclodextrin Inclusion Complexes into the Treatment of Glioblastoma

Authors: Kyriaki Hatziagapiou, Konstantinos Bethanis, Olti Nikola, Elias Christoforides, Eleni Koniari, Eleni Kakouri, George Lambrou, Christina Kanaka-Gantenbein

Abstract:

Glioblastoma multiforme (GBM) remains a serious health challenge, as current therapeutic modalities continue to yield unsatisfactory results, with the average survival rarely exceeding 1-2 years. Natural compounds still provide some of the most promising approaches for discovering new drugs. The non-psychotropic cannabidiol (CBD) deriving from Cannabis sativa L. provides such promise. CBD is endowed with anticancer, antioxidant, and genoprotective properties as established in vitro and in in vivo experiments. CBD’s selectivity towards cancer cells and its safe profile suggest its usage in cancer therapies. However, the bioavailability of oral CBD is low due to poor aqueous solubility, erratic gastrointestinal absorption, and significant first-pass metabolism, hampering its therapeutic potential and resulting in a variable pharmacokinetic profile. In this context, CBD can take great advantage of nanomedicine-based formulation strategies. Cyclodextrins (CDs) are cyclic oligosaccharides used in the pharmaceutical industry to incorporate apolar molecules inside their hydrophobic cavity, increasing their stability, water solubility, and bioavailability or decreasing their side effects. CBD-inclusion complexes with CDs could be a good strategy to improve its properties, like solubility and stability to harness its full therapeutic potential. The current research aims to study the potential cytotoxic effect of CBD and CBD-CDs complexes CBD-RMβCD (randomly methylated β-cyclodextrin) and CBD-HPβCD (hydroxypropyl-b-CD) on the A172 glioblastoma cell line. CBD is diluted in 10% DMSO, and CBD/CDs solutions are prepared by mixing solid CBD, solid CDs, and dH2O. For the biological assays, A172 cells are incubated at a range of concentrations of CBD, CBD-RMβCD and CBD-HPβCD, RMβCD, and HPβCD (0,03125-4 mg/ml) at 24, 48, and 72 hours. Analysis of cell viability after incubation with the compounds is performed with Alamar Blue viability assay. CBD’s dilution to DMSO 10% was inadequate, as crystals are observed; thus cytotoxicity experiments are not assessed. CBD’s solubility is enhanced in the presence of both CDs. CBD/CDs exert significant cytotoxicity in a dose and time-dependent manner (p < 0.005 for exposed cells to any concentration at 48, 72, and 96 hours versus cells not exposed); as their concentration and time of exposure increases, the reduction of resazurin to resofurin decreases, indicating a reduction in cell viability. The cytotoxic effect is more pronounced in cells exposed to CBD-HPβCD for all concentrations and time-points. RMβCD and HPβCD at the highest concentration of 4 mg/ml also exerted antitumor action per se since manifesting cell growth inhibition. The results of our study could afford the basis of research regarding the use of natural products and their inclusion complexes as anticancer agents and the shift to targeted therapy with higher efficacy and limited toxicity. Acknowledgments: The research is partly funded by ΙΚΥ (State Scholarships Foundation) – Post-doc Scholarships-Partnership Agreement 2014-2020.

Keywords: cannabidiol, cyclodextrins, glioblastoma, hydroxypropyl-b-Cyclodextrin, randomly-methylated-β-cyclodextrin

Procedia PDF Downloads 173
2977 Effects of Local Decongestive Agents at Trachea and Lungs

Authors: Sertac Arslan, Guven Guney, Ayse Ipek Akyuz Unsal, Emre Demir, Buket Demirci

Abstract:

Purpose: There is little histologic data concerning effects of nasal decongestants on the respiratory tract. We aimed to put forth the effects of nasal decongestants on the trachea and lower airways of rats. Materials and Methods: Four to six months old 60 male rats were randomly categorized into 6 groups. Experimental drugs were applied to the same nostril of rats twice daily for 8 weeks (Xylometazolin, Benzalkolyum, EDTA, Sorbitol and combined drug solutions). We applied normal saline solution (NaCl %0.9) for the control group. In the end, trachea and both lungs were dissected and kept in formaldehyde for histopathologic evaluation. Results: Inflammation and bronchial edema were most common findings. While all rats in sorbitol group had increased numbers of type 2 pneumocytes; 80% of BAC group had increased numbers of type 2 pneumocytes. Spillover of tracheal epithelium was seen mostly in sorbitol, EDTA and combined drug groups (60%, 87.5%, 50% respectively). Bronchial smooth muscle hypertrophy was seen mostly in BAC and EDTA group (70%, 62.5% respectively). The number of goblet cells showed the significant difference between control-combined drug (p=0.025) and control-BAC (p=0.001) groups. Conclusions: Nasal decongestants can cause permanent changes at lower respiratory tract in addition to changes in upper respiratory tract.

Keywords: decongestive agents, xylometazoline, lung, trachea

Procedia PDF Downloads 172
2976 Multi-Criteria Assessment of Biogas Feedstock

Authors: Rawan Hakawati, Beatrice Smyth, David Rooney, Geoffrey McCullough

Abstract:

Targets have been set in the EU to increase the share of renewable energy consumption to 20% by 2020, but developments have not occurred evenly across the member states. Northern Ireland is almost 90% dependent on imported fossil fuels. With such high energy dependency, Northern Ireland is particularly susceptible to the security of supply issues. Linked to fossil fuels are greenhouse gas emissions, and the EU plans to reduce emissions by 20% by 2020. The use of indigenously produced biomass could reduce both greenhouse gas emissions and external energy dependence. With a wide range of both crop and waste feedstock potentially available in Northern Ireland, anaerobic digestion has been put forward as a possible solution for renewable energy production, waste management, and greenhouse gas reduction. Not all feedstock, however, is the same, and an understanding of feedstock suitability is important for both plant operators and policy makers. The aim of this paper is to investigate biomass suitability for anaerobic digestion in Northern Ireland. It is also important that decisions are based on solid scientific evidence. For this reason, the methodology used is multi-criteria decision matrix analysis which takes multiple criteria into account simultaneously and ranks alternatives accordingly. The model uses the weighted sum method (which follows the Entropy Method to measure uncertainty using probability theory) to decide on weights. The Topsis method is utilized to carry out the mathematical analysis to provide the final scores. Feedstock that is currently available in Northern Ireland was classified into two categories: wastes (manure, sewage sludge and food waste) and energy crops, specifically grass silage. To select the most suitable feedstock, methane yield, feedstock availability, feedstock production cost, biogas production, calorific value, produced kilowatt-hours, dry matter content, and carbon to nitrogen ratio were assessed. The highest weight (0.249) corresponded to production cost reflecting a variation of £41 gate fee to 22£/tonne cost. The weights calculated found that grass silage was the most suitable feedstock. A sensitivity analysis was then conducted to investigate the impact of weights. The analysis used the Pugh Matrix Method which relies upon The Analytical Hierarchy Process and pairwise comparisons to determine a weighting for each criterion. The results showed that the highest weight (0.193) corresponded to biogas production indicating that grass silage and manure are the most suitable feedstock. Introducing co-digestion of two or more substrates can boost the biogas yield due to a synergistic effect induced by the feedstock to favor positive biological interactions. A further benefit of co-digesting manure is that the anaerobic digestion process also acts as a waste management strategy. From the research, it was concluded that energy from agricultural biomass is highly advantageous in Northern Ireland because it would increase the country's production of renewable energy, manage waste production, and would limit the production of greenhouse gases (current contribution from agriculture sector is 26%). Decision-making methods based on scientific evidence aid policy makers in classifying multiple criteria in a logical mathematical manner in order to reach a resolution.

Keywords: anaerobic digestion, biomass as feedstock, decision matrix, renewable energy

Procedia PDF Downloads 457
2975 Costume Design Influenced by Seventeenth Century Color Palettes on a Contemporary Stage

Authors: Michele L. Dormaier

Abstract:

The purpose of the research was to design costumes based on historic colors used by artists during the seventeenth century. The researcher investigated European art, primarily paintings and portraiture, as well as the color palettes used by the artists. The methodology examined the artists, their work, the color palettes used in their work, and the practices of color usage within their palettes. By examining portraits of historic figures, as well as paintings of ordinary scenes, subjects, and people, further information about color palettes was revealed. Related to the color palettes, was the use of ‘broken colors’ which was a relatively new practice, dating from the sixteenth century. The color palettes used by the artists of the seventeenth century had their limitations due to available pigments. With an examination of not only their artwork, and with a closer look at their palettes, the researcher discovered the exciting choices they made, despite those restrictions. The research was also initiated with the historical elements of the era’s clothing, as well as that of available materials and dyes. These dyes were also limited in much the same manner as the pigments which the artist had at their disposal. The color palettes of the paintings have much to tell us about the lives, status, conditions, and relationships from the past. From this research, informed decisions regarding color choices for a production on a contemporary stage of a period piece could then be made. The designer’s choices were a historic gesture to the colors which might have been worn by the character’s real-life counterparts of the era.

Keywords: broken color palette, costume color research, costume design, costume history, seventeenth century color palette, sixteenth century color palette

Procedia PDF Downloads 173
2974 Deep Cryogenic Treatment With Subsequent Aging Applied to Martensitic Stainless Steel: Evaluation of Hardness, Tenacity and Microstructure

Authors: Victor Manuel Alcántara Alza

Abstract:

The way in which the application of the deep cryogenic treatment DCT(-196°C) affects, applied with subsequent aging, was investigated, regarding the mechanical properties of hardness, toughness and microstructure, applied to martensitic stainless steels, with the aim of establishing a different methodology compared to the traditional DCT cryogenic treatment with subsequent tempering. For this experimental study, a muffle furnace was used, first subjecting the specimens to deep cryogenization in a liquid Nitrogen bath/4h, after being previously austenitized at the following temperatures: 1020-1030-1040-1050 (°C) / 1 hour; and then tempered in oil. A first group of cryogenic samples were subjected to subsequent aging at 150°C, with immersion times: 2.5 -5- 10 - 20 - 50 – 100 (h). The next group was subjected to subsequent tempering at temperatures: 480-500-510-520-530-540 (°C)/ 2h. The hardness tests were carried out under standards, using a Universal Durometer, and the readings were made on the HRC scale. The Impact Resistance tests were carried out in a Charpy machine following the ASTM E 23 – 93ª standard. Measurements were taken in joules. Microscopy was performed at the optical level using a 1000X microscope. It was found: For the entire aging interval, the samples austenitized at 1050°C present greater hardness than austenitized at 1040°C, with the maximum peak aged being at 30h. In all cases, the aged samples exceed the hardness of the tempered samples, even in their minimum values. In post-tempered samples, the tempering temperature hardly have effect on the impact strength of material. In the Cryogenic Treatment: DCT + subsequent aging, the maximum hardness value (58.7 HRC) is linked to an impact toughness value (54J) obtained with aging time of 39h, which is considered an optimal condition. The higher hardness of steel after the DCT treatment is attributed to the transformation of retained austenite into martensite. The microstructure is composed mainly of lath martensite; and the original grain size of the austenite can be appreciated. The choice of the combination: Hardness-toughness, is subject to the required service conditions of steel.

Keywords: deep cryogenic treatment; aged precipitation; martensitic steels;, mechanical properties; martensitic steels, hardness, carbides precipitaion

Procedia PDF Downloads 71
2973 Measurement of Natural Radioactivity and Health Hazard Index Evaluation in Major Soils of Tin Mining Areas of Perak

Authors: Habila Nuhu

Abstract:

Natural radionuclides in the environment can significantly contribute to human exposure to ionizing radiation. The knowledge of their levels in an environment can help the radiological protection agencies in policymaking. Measurement of natural radioactivity in major soils in the tin mining state of Perak Malaysia has been conducted using an HPGe detector. Seventy (70) soil samples were collected at widely distributed locations in the state. Six major soil types were sampled, and thirteen districts around the state were covered. The following were the results of the 226Ra (238U), 228Ra (232Th), and 40K activity in the soil samples: 226Ra (238U) has a mean activity concentration of 191.83 Bq kg⁻¹, more than five times the UNSCEAR reference limits of 35 Bq kg⁻¹. The mean activity concentration of 228Ra (232Th) with a value of 232.41 Bq kg⁻¹ is over seven times the UNSCEAR reference values of 30 Bq kg⁻¹. The average concentration of 40K activity was 275.24 Bq kg⁻¹, which was less than the UNSCEAR reference limit of 400 Bq Kg⁻¹. The range of external hazards index (Hₑₓ) values was from 1.03 to 2.05, while the internal hazards index (Hin) was from 1.48 to 3.08. The Hex and Hin should be less than one for minimal external and internal radiation threats as well as secure use of soil material for building construction. The Hₑₓ and Hin results generally indicate that while using the soil types and their derivatives as building materials in the study area, care must be taken.

Keywords: activity concentration, hazard index, soil samples, tin mining

Procedia PDF Downloads 105
2972 Nutritional Evaluation of Sea Buckthorn “Hippophae rhamnoides” Berries and the Pharmaceutical Potential of the Fermented Juice

Authors: Sobhy A. El-Sohaimy, Mohamed G. Shehata, Ashwani Mathur, Amira G. Darwish, Nourhan M. Abd El-Aziz, Pammi Gauba, Pooja Upadhyay

Abstract:

Sea buckthorn is a temperate bush plant native to Asian and European countries, explored across the world in traditional medicine to treat various diseases due to the presence of an exceptionally high content of phenolics, flavonoids and antioxidants. In addition to the evaluation of nutrients and active compounds, the focus of the present work was to assess the optimal levels for L. plantarum RM1 growth by applying response surface methodology (RSM), and to determine the impact of juice fermentation on antioxidant, anti-hypertension and anticancer activity, as well as on organoleptic properties. Sea buckthorn berries were shown to contain good fiber content (6.55%, 25 DV%), high quality of protein (3.12%, 6.24 DV%) containing: histidine, valine, threonine, leucine and lysine (with AAS 24.32, 23.66, 23.09, 23.05 and 21.71%, respectively), and 4.45% sugar that pro- vides only 79 calories. Potassium was shown to be the abundant mineral content (793.43%, 22.66 DV), followed by copper and phosphorus (21.81 and 11.07 DV%, respectively). Sea buckthorn juice exhibited a rich phenolic, flavonoid and carotenoid content (283.58, 118.42 and 6.5 mg/g, respec- tively), in addition to a high content of vitamin C (322.33 mg/g). The HPLC profile indicated that benzoic acid is the dominant phenolic compound in sea buckthorn berries (3825.90 mg/kg). Antiox- idant potentials (DPPH and ABTS) of sea buckthorn showed higher inhibition than ascorbic acid. Antimicrobial potentials were most pronounced against Escherichia coli BA12296 (17.46 mm). The probiotic growth was 8.5 log cfu/mL, with juice concentration, inoculum size and temperature as the main contributors to probiotic growth with a 95% confidence level. Fermentation of sea buck- thorn juice with L. plantarum RM1 enhanced the functional phenolic and flavonoid content, as well as antioxidant and antimicrobial activities. The fermentation with L. plantarum RM1 enhanced the anti-hypertension and anticancer properties of the sea buckthorn juice and gained consumers’ sensorial overall acceptance.

Keywords: sea buckthorn juice, L. plantarum RM1, fermentation, antioxidant, antimicrobial, angiotensin converting enzyme inhibition

Procedia PDF Downloads 93
2971 Behaviour of Model Square Footing Resting on Three Dimensional Geogrid Reinforced Sand Bed

Authors: Femy M. Makkar, S. Chandrakaran, N. Sankar

Abstract:

The concept of reinforced earth has been used in the field of geotechnical engineering since 1960s, for many applications such as, construction of road and rail embankments, pavements, retaining walls, shallow foundations, soft ground improvement and so on. Conventionally, planar geosynthetic materials such as geotextiles and geogrids were used as the reinforcing elements. Recently, the use of three dimensional reinforcements becomes one of the emerging trends in this field. So, in the present investigation, three dimensional geogrid is proposed as a reinforcing material. Laboratory scaled plate load tests are conducted on a model square footing resting on 3D geogrid reinforced sand bed. The performance of 3D geogrids in triangular and square pattern was compared with conventional geogrids and the improvement in bearing capacity and reduction in settlement and heave are evaluated. When single layer of reinforcement was placed at an optimum depth of 0.25B from the bottom of the footing, the bearing capacity of conventional geogrid reinforced soil improved by 1.85 times compared to unreinforced soil, where as 3D geogrid reinforced soil with triangular pattern and square pattern shows 2.69 and 3.05 times improvement respectively compared to unreinforced soil. Also, 3D geogrids performs better than conventional geogrids in reducing the settlement and heave of sand bed around the model footing.

Keywords: 3D reinforcing elements, bearing capacity, heavy, settlement

Procedia PDF Downloads 296
2970 Design and Modelling of Ge/GaAs Hetero-structure Bipolar Transistor

Authors: Samson Mil'shtein, Dhawal N. Asthana

Abstract:

The presented heterostructure n-p-n bipolar transistor is comprised of Ge/GaAs heterojunctions consisting of 0.15µm thick emitter and 0.65µm collector junctions. High diffusivity of carriers in GaAs base was major motivation of current design. We avoided grading of the base which is common in heterojunction bipolar transistors, in order to keep the electron diffusivity as high as possible. The electrons injected into the 0.25µm thick p-type GaAs base with not very high doping (1017cm-3). The designed HBT enables cut off frequency on the order of 150GHz. The Ge/GaAs heterojunctions presented in our paper have proved to work better than comparable HBTs having GaAs bases and emitter/collector junctions made, for example, of AlGaAs/GaAs or other III-V compound semiconductors. The difference in lattice constants between Ge and GaAs is less than 2%. Therefore, there is no need of transition layers between Ge emitter and GaAs base. Significant difference in energy gap of these two materials presents new scope for improving performance of the emitter. With the complete structure being modelled and simulated using TCAD SILVACO, the collector/ emitter offset voltage of the device has been limited to a reasonable value of 63 millivolts by the dint of low energy band gap value associated with Ge emitter. The efficiency of the emitter in our HBT is 86%. Use of Germanium in the emitter and collector regions presents new opportunities for integration of this vertical device structure into silicon substrate.

Keywords: Germanium, Gallium Arsenide, heterojunction bipolar transistor, high cut-off frequency

Procedia PDF Downloads 417
2969 Embodied Empowerment: A Design Framework for Augmenting Human Agency in Assistive Technologies

Authors: Melina Kopke, Jelle Van Dijk

Abstract:

Persons with cognitive disabilities, such as Autism Spectrum Disorder (ASD) are often dependent on some form of professional support. Recent transformations in Dutch healthcare have spurred institutions to apply new, empowering methods and tools to enable their clients to cope (more) independently in daily life. Assistive Technologies (ATs) seem promising as empowering tools. While ATs can, functionally speaking, help people to perform certain activities without human assistance, we hold that, from a design-theoretical perspective, such technologies often fail to empower in a deeper sense. Most technologies serve either to prescribe or to monitor users’ actions, which in some sense objectifies them, rather than strengthening their agency. This paper proposes that theories of embodied interaction could help formulating a design vision in which interactive assistive devices augment, rather than replace, human agency and thereby add to a persons’ empowerment in daily life settings. It aims to close the gap between empowerment theory and the opportunities provided by assistive technologies, by showing how embodiment and empowerment theory can be applied in practice in the design of new, interactive assistive devices. Taking a Research-through-Design approach, we conducted a case study of designing to support independently living people with ASD with structuring daily activities. In three iterations we interlaced design action, active involvement and prototype evaluations with future end-users and healthcare professionals, and theoretical reflection. Our co-design sessions revealed the issue of handling daily activities being multidimensional. Not having the ability to self-manage one’s daily life has immense consequences on one’s self-image, and also has major effects on the relationship with professional caregivers. Over the course of the project relevant theoretical principles of both embodiment and empowerment theory together with user-insights, informed our design decisions. This resulted in a system of wireless light units that users can program as a reminder for tasks, but also to record and reflect on their actions. The iterative process helped to gradually refine and reframe our growing understanding of what it concretely means for a technology to empower a person in daily life. Drawing on the case study insights we propose a set of concrete design principles that together form what we call the embodied empowerment design framework. The framework includes four main principles: Enabling ‘reflection-in-action’; making information ‘publicly available’ in order to enable co-reflection and social coupling; enabling the implementation of shared reflections into an ‘endurable-external feedback loop’ embedded in the persons familiar ’lifeworld’; and nudging situated actions with self-created action-affordances. In essence, the framework aims for the self-development of a suitable routine, or ‘situated practice’, by building on a growing shared insight of what works for the person. The framework, we propose, may serve as a starting point for AT designers to create truly empowering interactive products. In a set of follow-up projects involving the participation of persons with ASD, Intellectual Disabilities, Dementia and Acquired Brain Injury, the framework will be applied, evaluated and further refined.

Keywords: assistive technology, design, embodiment, empowerment

Procedia PDF Downloads 276
2968 Local Buckling of Web-Core and Foam-Core Sandwich Panels

Authors: Ali N. Suri, Ahmad A. Al-Makhlufi

Abstract:

Sandwich construction is widely accepted as a method of construction especially in the aircraft industry. It is a type of stressed skin construction formed by bonding two thin faces to a thick core, the faces resist all of the applied edge loads and provide all or nearly all of the required rigidities, the core spaces the faces to increase cross section moment of inertia about common neutral axis and transmit shear between them provides a perfect bond between core and faces is made. Material for face sheets can be of metal or reinforced plastics laminates, core material can be metallic cores of thin sheets forming corrugation or honeycomb, or non-metallic core of Balsa wood, plastic foams, or honeycomb made of reinforced plastics. For in plane axial loading web core and web-foam core Sandwich panels can fail by local buckling of plates forming the cross section with buckling wave length of the order of length of spacing between webs. In this study local buckling of web core and web-foam core Sandwich panels is carried out for given materials of facing and core, and given panel overall dimension for different combinations of cross section geometries. The Finite Strip Method is used for the analysis, and Fortran based computer program is developed and used.

Keywords: local buckling, finite strip, sandwich panels, web and foam core

Procedia PDF Downloads 347
2967 Starch Valorization: Biorefinery Concept for the Circular Bioeconomy

Authors: Maider Gómez Palmero, Ana Carrasco Pérez, Paula de la Sen de la Cruz, Francisco Javier Royo Herrer, Sonia Ascaso Malo

Abstract:

The production of bio-based products for different purposes is one of the strategies that has grown the most at European and even global levels, seeking to contribute to mitigating the impacts associated with climate change and to achieve the ambitious objectives set in this regard. However, the substitution of fossil-based products for bio-based products requires a challenging and deep transformation and adaptation of the secondary and primary sectors and, more specifically, in the latter, the agro-industries. The first step to developing a bio-based value chain focuses on the availability of a resource with the right characteristics for the substitution sought. This, in turn, requires a significant reshaping of the forestry/agricultural sector but also of the agro-industry, which has a relevant potential to be deployed as a supplier and develop a robust logistical supply chain and to market a biobased raw material at a competitive price. However, this transformation may involve a profound restructuring of its traditional business model to incorporate biorefinery concepts. In this sense, agro-industries that generate by-products in their processes that are currently not valorized, such as potato processing rejects or the starch found in washing water, constitute a potential raw material that can be used for different bio-applications. This article aims to explore this potential to evaluate the most suitable bio applications to target and identify opportunities and challenges.

Keywords: starch valorisation, biorefinery, bio-based raw materials, bio-applications

Procedia PDF Downloads 44
2966 Effect of Inclusion of Rubber on the Compaction Characteristics of Cement - MSWIFA- Clayey Soil Mixtures

Authors: Gehan Aouf, Diala Tabbal, Abd El Rahim Sabsabi, Rashad Aouf

Abstract:

The aim of this study is to show the effect of adding cement municipal solid incineration fly ash and rubber as stabilizer materials on weak soil. A detailed experimental study was conducted in order to show the viability of using these admixtures in improving the maximum dry density and optimum moisture content of the composite soil. Soil samples were prepared by adding Rubber and Cement to municipal solid waste incineration fly-ash - oil mix at different percentages. Then, a series of laboratory tests were performed, namely: Sieve analysis, Atterberg limits tests, Unconfined compression test, and Proctor tests. Three different percentages of fly ash (10%, 20%, and 30%) MSWFA by total dry weight of soil and three different percentages of Portland cement (10%, 15%, and 20%) by total dry weight of the mix and 0%, 5%, 10% for Rubber by total dry weight of the mix were used to find the optimum value. The test results reveal that adding MSWIFA to the soil up to 20% increased the MDD of the mixture and decreased the OMC, then an opposite trend for results were found when the percentage of MSWIFA exceeded 20%. This is due to the low specific gravity of MSWIFA and to the greater water absorption of MSWIFA. The laboratory tests also indicate that adding Rubber to the mix Soil-MSWIFA-Cement decreases its MDD due to the low specific gravity of rubber and it affects a slight decrease in OMC because the rubber has low absorption of water.

Keywords: clayey soil, MSWIFA, proctor test, rubber

Procedia PDF Downloads 112
2965 Breaking Sensitivity Barriers: Perovskite Based Gas Sensors With Dimethylacetamide-Dimethyl Sulfoxide Solvent Mixture Strategy

Authors: Endalamaw Ewnu Kassa, Ade Kurniawan, Ya-Fen Wu, Sajal Biring

Abstract:

Perovskite-based gas sensors represent a highly promising materials within the realm of gas sensing technology, with a particular focus on detecting ammonia (NH3) due to its potential hazards. Our work conducted thorough comparison of various solvents, including dimethylformamide (DMF), DMF-dimethyl sulfoxide (DMSO), dimethylacetamide (DMAC), and DMAC-DMSO, for the preparation of our perovskite solution (MAPbI3). Significantly, we achieved an exceptional response at 10 ppm of ammonia gas by employing a binary solvent mixture of DMAC-DMSO. In contrast to prior reports that relied on single solvents for MAPbI3 precursor preparation, our approach using mixed solvents demonstrated a marked improvement in gas sensing performance. We attained enhanced surface coverage, a reduction in pinhole occurrences, and precise control over grain size in our perovskite films through the careful selection and mixtures of appropriate solvents. This study shows a promising potential of employing binary and multi-solvent mixture strategies as a means to propel advancements in gas sensor technology, opening up new opportunities for practical applications in environmental monitoring and industrial safety.

Keywords: sensors, binary solvents, ammonia, sensitivity, grain size, pinholes, surface coverage

Procedia PDF Downloads 98
2964 Ensemble Methods in Machine Learning: An Algorithmic Approach to Derive Distinctive Behaviors of Criminal Activity Applied to the Poaching Domain

Authors: Zachary Blanks, Solomon Sonya

Abstract:

Poaching presents a serious threat to endangered animal species, environment conservations, and human life. Additionally, some poaching activity has even been linked to supplying funds to support terrorist networks elsewhere around the world. Consequently, agencies dedicated to protecting wildlife habitats have a near intractable task of adequately patrolling an entire area (spanning several thousand kilometers) given limited resources, funds, and personnel at their disposal. Thus, agencies need predictive tools that are both high-performing and easily implementable by the user to help in learning how the significant features (e.g. animal population densities, topography, behavior patterns of the criminals within the area, etc) interact with each other in hopes of abating poaching. This research develops a classification model using machine learning algorithms to aid in forecasting future attacks that is both easy to train and performs well when compared to other models. In this research, we demonstrate how data imputation methods (specifically predictive mean matching, gradient boosting, and random forest multiple imputation) can be applied to analyze data and create significant predictions across a varied data set. Specifically, we apply these methods to improve the accuracy of adopted prediction models (Logistic Regression, Support Vector Machine, etc). Finally, we assess the performance of the model and the accuracy of our data imputation methods by learning on a real-world data set constituting four years of imputed data and testing on one year of non-imputed data. This paper provides three main contributions. First, we extend work done by the Teamcore and CREATE (Center for Risk and Economic Analysis of Terrorism Events) research group at the University of Southern California (USC) working in conjunction with the Department of Homeland Security to apply game theory and machine learning algorithms to develop more efficient ways of reducing poaching. This research introduces ensemble methods (Random Forests and Stochastic Gradient Boosting) and applies it to real-world poaching data gathered from the Ugandan rain forest park rangers. Next, we consider the effect of data imputation on both the performance of various algorithms and the general accuracy of the method itself when applied to a dependent variable where a large number of observations are missing. Third, we provide an alternate approach to predict the probability of observing poaching both by season and by month. The results from this research are very promising. We conclude that by using Stochastic Gradient Boosting to predict observations for non-commercial poaching by season, we are able to produce statistically equivalent results while being orders of magnitude faster in computation time and complexity. Additionally, when predicting potential poaching incidents by individual month vice entire seasons, boosting techniques produce a mean area under the curve increase of approximately 3% relative to previous prediction schedules by entire seasons.

Keywords: ensemble methods, imputation, machine learning, random forests, statistical analysis, stochastic gradient boosting, wildlife protection

Procedia PDF Downloads 287
2963 Special Single Mode Fiber Tests of Polarization Mode Dispersion Changes in a Harsh Environment

Authors: Jan Bohata, Stanislav Zvanovec, Matej Komanec, Jakub Jaros, David Hruby

Abstract:

Even though there is a rapid development in new optical networks, still optical communication infrastructures remain composed of thousands of kilometers of aging optical cables. Many of them are located in a harsh environment which contributes to an increased attenuation or induced birefringence of the fibers leading to the increase of polarization mode dispersion (PMD). In this paper, we report experimental results from environmental optical cable tests and characterization in the climate chamber. We focused on the evaluation of optical network reliability in a harsh environment. For this purpose, a special thermal chamber was adopted, targeting to the large temperature changes between -60 °C and 160 C° with defined humidity. Single mode optical cable 230 meters long, having six tubes and a total number of 72 single mode optical fibers was spliced together forming one fiber link, which was afterward tested in the climate chamber. The main emphasis was put to the polarization mode dispersion (PMD) changes, which were evaluated by three different PMD measuring methods (general interferometry technique, scrambled state-of-polarization analysis and polarization optical time domain reflectometer) in order to fully validate obtained results. Moreover, attenuation and chromatic dispersion (CD), as well as the PMD, were monitored using 17 km long single mode optical cable. Results imply a strong PMD dependence on thermal changes, imposing the exceeding 200 % of its value during the exposure to extreme temperatures and experienced more than 20 dB insertion losses in the optical system. The derived statistic is provided in the paper together with an evaluation of such as optical system reliability, which could be a crucial tool for the optical network designers. The environmental tests are further taken in context to our previously published results from long-term monitoring of fundamental parameters within an optical cable placed in a harsh environment in a special outdoor testbed. Finally, we provide a correlation between short-term and long-term monitoring campaigns and statistics, which are necessary for optical network safety and reliability.

Keywords: optical fiber, polarization mode dispersion, harsh environment, aging

Procedia PDF Downloads 379
2962 Parametric Investigation of Aircraft Door’s Emergency Power Assist System (EPAS)

Authors: Marshal D. Kafle, Jun H. Kim, Hyun W. Been, Kyoung M. Min

Abstract:

Fluid viscous damping systems are well suited for many air vehicles subjected to shock and vibration. These damping system work with the principle of viscous fluid throttling through the orifice to create huge pressure difference between compression and rebound chamber and obtain the required damping force. One application of such systems is its use in aircraft door system to counteract the door’s velocity and safely stop it. In exigency situations like crash or emergency landing where the door doesn’t open easily, possibly due to unusually tilting of fuselage or some obstacles or intrusion of debris obstruction to move the parts of the door, such system can be combined with other systems to provide needed force to forcefully open the door and also securely stop it simultaneously within the required time i.e.less than 8seconds. In the present study, a hydraulic system called snubber along with other systems like actuator, gas bottle assembly which together known as emergency power assist system (EPAS) is designed, built and experimentally studied to check the magnitude of angular velocity, damping force and time required to effectively open the door. Whenever needed, the gas pressure from the bottle is released to actuate the actuator and at the same time pull the snubber’s piston to operate the emergency opening of the door. Such EPAS installed in the suspension arm of the aircraft door is studied explicitly changing parameters like orifice size, oil level, oil viscosity and bypass valve gap and its spring of the snubber at varying temperature to generate the optimum design case. Comparative analysis of the EPAS at several cases is done and conclusions are made. It is found that during emergency condition, the systemopening time and angular velocity, when snubber with 0.3mm piston and shaft orifice and bypass valve gap of 0.5 mm with its original spring is used,shows significant improvement over the old ones.

Keywords: aircraft door damper, bypass valve, emergency power assist system, hydraulic damper, oil viscosity

Procedia PDF Downloads 421
2961 Effects of in silico (Virtual Lab) And in vitro (inside the Classroom) Labs in the Academic Performance of Senior High School Students in General Biology

Authors: Mark Archei O. Javier

Abstract:

The Fourth Industrial Revolution (FIR) is a major industrial era characterized by the fusion of technologies that is blurring the lines between the physical, digital, and biological spheres. Since this era teaches us how to thrive in the fast-paced developing world, it is important to be able to adapt. With this, there is a need to make learning and teaching in the bioscience laboratory more challenging and engaging. The goal of the research is to find out if using in silico and in vitro laboratory activities compared to the conventional conduct laboratory activities would have positive impacts on the academic performance of the learners. The potential contribution of the research is that it would improve the teachers’ methods in delivering the content to the students when it comes to topics that need laboratory activities. This study will develop a method by which teachers can provide learning materials to the students. A one-tailed t-Test for independent samples was used to determine the significant difference in the pre- and post-test scores of students. The tests of hypotheses were done at a 0.05 level of significance. Based on the results of the study, the gain scores of the experimental group are greater than the gain scores of the control group. This implies that using in silico and in vitro labs for the experimental group is more effective than the conventional method of doing laboratory activities.

Keywords: academic performance, general biology, in silico laboratory, in vivo laboratory, virtual laboratory

Procedia PDF Downloads 188
2960 The Effect of the Earthworm (Lumbricus rubellus) as the Source of Protein Feed and Pathogen Antibacterial for Broiler

Authors: Waode Nurmayani, Nikmatul Riswanda

Abstract:

Broilers are chickens which are kept with the most efficient time and hoped get a good body weight. All things are done, for example with the improvement of feed and use antibiotics. Feed cost is the most cost to be spent. Nearly 80% of the cost is spent just for buy feed. Earthworm (Lumbricus rubellus) is a good choice to reduce the cost of feed protein source. The Earthworm has a high crude protein content of about 48.5%-61.9%, rich with proline amino acid about 15% of the 62 amino acids. Not only about protein, this earthworm also has a role in disease prevention. Prevention of disease in livestock usual with use feed supplement. Earthworm (Lumbricus rubellus) is one of the natural materials used as feed. In addition, several types of earthworms that have been known to contain active substances about antibacterial pathogens namely Lumbricus rubellus. The earthworm could be used as an antibiotic because it contain the antibody of Lumbricine active substance. So that, this animal feed from Lumbricus rubellus could improve the performance of broilers. Bioactive of anti-bacterial is called Lumbricine able to inhibit the growth of pathogenic bacteria in the intestinal wall so that the population of pathogenic bacteria is reduced. The method of write in this scientific writing is divided into 3 techniques, namely data completion, data analysis, and thinking pan from various literature about earthworm (Lumbricus rubellus) as broiler feed. It is expected that innovation of feed material of earthworm (Lumbricus rubellus) could reduce the cost of protein feed and the use of chemical antibiotics.

Keywords: earthworm, broiler, protein, antibiotic

Procedia PDF Downloads 150
2959 Inventory Management System of Seasonal Raw Materials of Feeds at San Jose Batangas through Integer Linear Programming and VBA

Authors: Glenda Marie D. Balitaan

Abstract:

The branch of business management that deals with inventory planning and control is known as inventory management. It comprises keeping track of supply levels and forecasting demand, as well as scheduling when and how to plan. Keeping excess inventory results in a loss of money, takes up physical space, and raises the risk of damage, spoilage, and loss. On the other hand, too little inventory frequently causes operations to be disrupted and raises the possibility of low customer satisfaction, both of which can be detrimental to a company's reputation. The United Victorious Feed mill Corporation's present inventory management practices were assessed in terms of inventory level, warehouse allocation, ordering frequency, shelf life, and production requirement. To help the company achieve their optimal level of inventory, a mathematical model was created using Integer Linear Programming. Due to the season, the goal function was to reduce the cost of purchasing US Soya and Yellow Corn. Warehouse space, annual production requirements, and shelf life were all considered. To ensure that the user only uses one application to record all relevant information, like production output and delivery, the researcher built a Visual Basic system. Additionally, the technology allows management to change the model's parameters.

Keywords: inventory management, integer linear programming, inventory management system, feed mill

Procedia PDF Downloads 77
2958 Development of Enzymatic Amperometric Biosensors with Carbon Nanotubes Decorated with Iron Oxide Nanoparticles

Authors: Uc-Cayetano E. G., Ake-Uh O. E., Villanueva-Mena I. E., Ordonez L. C.

Abstract:

Carbon nanotubes (CNTs) and other graphitic nanostructures are materials with extraordinary physical, physicochemical and electrochemical properties which are being aggressively investigated for a variety of sensing applications. Thus, sensing of biological molecules such as proteins, DNA, glucose and other enzymes using either single wall or multiwall carbon nanotubes (MWCNTs) has been widely reported. Despite the current progress in this area, the electrochemical response of CNTs used in a variety of sensing arrangements still needs to be improved. An alternative towards the enhancement of this CNTs' electrochemical response is to chemically (or physically) modify its surface. The influence of the decoration with iron oxide nanoparticles in different types of MWCNTs on the amperometric sensing of glucose, urea, and cholesterol in solution is investigated. Commercial MWCNTs were oxidized in acid media and subsequently decorated with iron oxide nanoparticles; finally, the enzymes glucose oxidase, urease, and cholesterol oxidase are chemically immobilized to oxidized and decorated MWCNTs for glucose, urease, and cholesterol electrochemical sensing. The results of the electrochemical characterizations consistently show that the presence of iron oxide nanoparticles decorating the surface of MWCNTs enhance the amperometric response and the sensitivity to increments in glucose, urease, and cholesterol concentration when compared to non-decorated MWCNTs.

Keywords: WCNTs, enzymes, oxidation, decoration

Procedia PDF Downloads 125
2957 Human Activities Damaging the Ecosystem of Isheri Ogun River, South West Nigeria

Authors: N. B. Ikenweiwe, A. A. Alimi, N. A. Bamidele, O. A. Ewumi, K. Fasina, S. O. Otubusin

Abstract:

A study on the physical, chemical and biological parameters of the lower course of Ogun River, Isheri-Olofin was carried out between January and December 2014 in order to determine the effects of the anthropogenic activities of the Kara abattoir and domestic waste depositions on the quality of the water. Water samples were taken twice each month at three selected stations A, B and C (based on characteristic features or activity levels) along the water course. Samples were analysed using standard methods for chemical and biological parameters the same day in the laboratory while physical parameters were determined in-situ with water parameters kit. Generally, results of Transparency, Dissolved Oxygen, Nitrates, TDS and Alkalinity fall below the permissible limits of WHO and FEPA standards for drinking and fish production. Results of phosphates, lead and cadmium were also low but still within the permissible limit. Only Temperature and pH were within limit. Low plankton community, (phytoplankton, zooplankton), which ranges from 3, 5 to 40, 23 were as a result of low levels of DO, transparency and phosphate. The presence of coliform bacteria of public health importance like Escherichia coli, Proteus vulgaris, Aeromonas sp., Shigella sp, Enterobacter aerogenes as well as gram negative bacteria Proteus morganii are mainly indicators of faecal pollution. Fish and other resources obtained from this water stand the risk of being contaminated with these organisms and man is at the receiving end. The results of the physical, chemical and some biological parameters of Isheri, Ogun River, according to this study showed that the live forms of aquatic and fisheries resources there are dwelling under stress as a result of deposition of bones, horns, faecal components, slurry of suspended solids, fat and blood into the water. Government should therefore establish good monitoring system against illegal waste depositions and create education programmes that will enlighten the community on the social, ecological and economic values of the river.

Keywords: damage, ecosystem, human activities, Isheri ogun river

Procedia PDF Downloads 536
2956 Housing Delivery in Nigeria’s Urban Areas: The Plight of the Poor in Owerri, Capital of Imo State, Nigeria

Authors: Joachim Onyike

Abstract:

The Federal Government of Nigeria in 2012 came up with a new National Housing Policy; one of its major objectives was to make housing affordable to the poor. Six years down the line, this study was carried out to find out whether the poor have fared better under the new housing policy. Owerri, the capital of Imo State, was adopted as a case study to mirror the situation nationwide. The study population was made up of low-income civil servants, i.e., grade levels 1–6 in the Imo State Civil Service. The study looked at household size, household income, rental levels, house prices, costs of major building materials, land values, land tenure, the interest rate on mortgages, inflation rate, and the status of government interventions, owing to their obvious effect on housing affordability by the low-income earners. The study made use of physical observations, questionnaires, and interviews as well as library studies to elicit relevant information. Housing affordability by the subject population did not improve. It rather dropped. The study came to the conclusion that in spite of the new National Housing Policy, housing affordability by the low-income earners has not improved. The policy as it affects the poor has not been duly implemented by both Federal and State Governments.

Keywords: house prices, housing affordability, housing policy, land values, low-income earners

Procedia PDF Downloads 192
2955 Zeolite Origin within the Pliocene Sedimentary-Pyroclastic Deposits in the Southwestern Part of Syria

Authors: Abdulsalam Turkmani, Mohammed Khaled Yezbek, Farouk Al Imadi

Abstract:

Geological surveys in the southwestern part of Syria showed the presence of sedimentary-pyroclastic deposits, volcanic tuff, to the age of the Upper Pliocene and contain the following minerals according petrographical study and XRD, SEM, XRF analysis and surface properties. X-Ray diffraction results indicate the presence of analcime, phillipsite and chabazite in in all the studied localities. There are also amorphous materials and clay minerals such as illite and montmorillonite. The non-zeolite constituents include olivine, clinopyroxene orthopyroxene and spinel, and less of magnetite and feldspar. Some major oxides were determined through XRF geochemical analyses which include SiO₂, Al₂O₃, K₂O, Fe₂O₃, and CaO for volcanic tuff and zeolite. The formation of these depositions can be summarized in the following stages during the Pliocene: Volcanic activity at the edges of Al Rutba uplift and Jabal Al Arab depression was a rich by tuff bearing ultra basic and basic xenoliths plus second phase by scoria, during the early Pliocene. Volcanic calm with the activity of erosion and form lakes in which deposition of a set of wastes, including olivine resulting from the disintegration of xenoliths during the middle Pliocene. Zeolites minerals form later, which make up about 15-20% and increase and decrease in reverse relation with the olivine sand. Zeolite is formed from volcanic glass, and the results of SEM show that the zeolites minerals very well crystallized.

Keywords: minerals, origin, pyroclastic, zeolite

Procedia PDF Downloads 179
2954 Critical Factors in the Formation, Development and Survival of an Eco-Industrial Park: A Systemic Understanding of Industrial Symbiosis

Authors: Iván González, Pablo Andrés Maya, Sebastián Jaén

Abstract:

Eco-industrial parks (EIPs) work as networks for the exchange of by-products, such as materials, water, or energy. This research identifies the relevant factors in the formation of EIPs in different industrial environments around the world. Then an aggregation of these factors is carried out to reduce them from 50 to 17 and classify them according to 5 fundamental axes. Subsequently, the Vester Sensitivity Model (VSM) systemic methodology is used to determine the influence of the 17 factors on an EIP system and the interrelationship between them. The results show that the sequence of effects between factors: Trust and Cooperation → Business Association → Flows → Additional Income represents the “backbone” of the system, being the most significant chain of influences. In addition, the Organizational Culture represents the turning point of the Industrial Symbiosis on which it must act correctly to avoid falling into unsustainable economic development. Finally, the flow of Information should not be lost since it is what feeds trust between the parties, and the latter strengthens the system in the face of individual or global imbalances. This systemic understanding will enable the formulation of pertinent policies by the actors that interact in the formation and permanence of the EIP. In this way, it seeks to promote large-scale sustainable industrial development, integrating various community actors, which in turn will give greater awareness and appropriation of the current importance of sustainability in industrial production.

Keywords: critical factors, eco-industrial park, industrial symbiosis, system methodology

Procedia PDF Downloads 116
2953 Physicochemical and Microbiological Assessment of Source and Stored Domestic Water from Three Local Governments in Ile-Ife, Nigeria

Authors: Mary A. Bisi-Johnson, Kehinde A. Adediran, Saheed A. Akinola, Hamzat A. Oyelade

Abstract:

Some of the main problems man contends with are the quantity (source and amount) and quality of water in Nigeria. Scarcity leads to water being obtained from various sources and microbiological contaminations of the water may thus occur between the collection point and the point of usage. Thus, this study aims to assess the general and microbiological quality of domestic water sources and household stored water used within selected areas in Ile-Ife, South-Western part of Nigeria for microbial contaminants. Physicochemical and microbiological examination were carried out on 45 source and stored water samples collected from well and spring in three different local government areas i.e. Ife east, Ife-south, and Ife-north. Physicochemical analysis included pH value, temperature, total dissolved solid, dissolved oxygen, and biochemical oxygen demand. Microbiology involved most probable number analysis, total coliform, heterotrophic plate, faecal coliform, and streptococcus count. The result of the physicochemical analysis of samples showed anomalies compared to acceptable standards with the pH value of 7.20-8.60 for stored and 6.50-7.80 for source samples as the total dissolved solids (TDS of stored 20-70mg/L, source 352-691mg/L), dissolved oxygen (DO of stored 1.60-9.60mg/L, source 1.60-4.80mg/L), biochemical oxygen demand (BOD stored 0.80-3.60mg/L, source 0.60-5.40mg/L). General microbiological quality indicated that both stored and source samples with the exception of a sample were not within acceptable range as indicated by analysis of the MPN/100ml which ranges (stored 290-1100mg/L, source 9-1100mg/L). Apart from high counts, most samples did not meet the World Health Organization standard for drinking water with the presence of some pathogenic bacteria and fungi such as Salmonella and Aspergillus spp. To annul these constraints, standard treatment methods should be adopted to make water free from contaminants. This will help identify common and likely water related infection origin within the communities and thus help guide in terms of interventions required to prevent the general populace from such infections.

Keywords: domestic, microbiology, physicochemical, quality, water

Procedia PDF Downloads 354
2952 Surface Modified Polyvinylidene Fluoride Membranes for Potential Use in Membrane Distillation

Authors: Lebea Nthunya, Arne Verliefde, Bhekie Mamba, Sabelo Mhlanga

Abstract:

A study aimed at developing membrane distillation (MD) processes that can be used for brackish/saline water purification will be presented. MD is a membrane-based technology that presents a possibility to counteract challenges associated with pressure driven membranes at high separation efficiencies. Membrane distillation membranes (MDM) are affected by wettability and fouling. Wetting inside the pores of the membrane is elevated by the hydrophilic characteristic of the membrane, while fouling is mostly induced by the hydrophobic-hydrophobic interaction of pollutants and the surface of the hydrophobic membranes, hence block the pores of the membranes. These properties are not desirable. As such, a carefully designed polyvinylidene fluoride (PVDF) MDM composed of a super-hydrophobic modified backbone and a super-hydrophilic thin layer has been developed to concurrently overcome these challenges. The membranes were characterized using contact angle measurements to confirm their hydrophobicity/hydrophilicity. SEM and SAXS were used to study the morphology and pore distribution on the surface of the membrane. The contact angles of the active surface ≤ 30º and that of the backbone ≥ 140º has thus revealed that the active surface was highly hydrophilic while the backbone was highly hydrophobic. The SEM and the SAXS results have also confirmed that the membranes are highly porous. These materials demonstrated a potential to remove salts from water at high efficiencies.

Keywords: membrane distillation, modification, energy efficiency, desalination

Procedia PDF Downloads 250
2951 Synthesis of Chitosan/Silver Nanocomposites: Antibacterial Properties and Tissue Regeneration for Thermal Burn Injury

Authors: B.L. España-Sánchez, E. Luna-Hernández, R.A. Mauricio-Sánchez, M.E. Cruz-Soto, F. Padilla-Vaca, R. Muñoz, L. Granados-López, L.R. Ovalle-Flores, J.L. Menchaca-Arredondo, G. Luna-Bárcenas

Abstract:

Treatment of burn injured has been considered an important clinical problem due to the fluid control and the presence of microorganisms during the healing process. Conventional treatment includes antiseptic techniques, topical medication and surgical removal of damaged skin, to avoid bacterial growth. In order to accelerate this process, different alternatives for tissue regeneration have been explored, including artificial skin, polymers, hydrogels and hybrid materials. Some requirements consider a nonreactive organic polymer with high biocompatibility and skin adherence, avoiding bacterial infections. Chitin-derivative biopolymer such as chitosan (CS) has been used in skin regeneration following third-degree burns. The biological interest of CS is associated with the improvement of tissue cell stimulation, biocompatibility and antibacterial properties. In particular, antimicrobial properties of CS can be significantly increased when is blended with nanostructured materials. Silver-based nanocomposites have gained attention in medicine due to their high antibacterial properties against pathogens, related to their high surface area/volume ratio at nanomolar concentrations. Silver nanocomposites can be blended or synthesized with chitin-derivative biopolymers in order to obtain a biodegradable/antimicrobial hybrid with improved physic-mechanical properties. In this study, nanocomposites based on chitosan/silver nanoparticles (CS/nAg) were synthesized by the in situ chemical reduction method, improving their antibacterial properties against pathogenic bacteria and enhancing the healing process in thermal burn injuries produced in an animal model. CS/nAg was prepared in solution by the chemical reduction method, using AgNO₃ as precursor. CS was dissolved in acetic acid and mixed with different molar concentrations of AgNO₃: 0.01, 0.025, 0.05 and 0.1 M. Solutions were stirred at 95°C during 20 hours, in order to promote the nAg formation. CS/nAg solutions were placed in Petri dishes and dried, to obtain films. Structural analyses confirm the synthesis of silver nanoparticles (nAg) by means of UV-Vis and TEM, with an average size of 7.5 nm and spherical morphology. FTIR analyses showed the complex formation by the interaction of hydroxyl and amine groups with metallic nanoparticles, and surface chemical analysis (XPS) shows low concentration of Ag⁰/Ag⁺ species. Topography surface analyses by means of AFM shown that hydrated CS form a mesh with an average diameter of 10 µm. Antibacterial activity against S. aureus and P. aeruginosa was improved in all evaluated conditions, such as nAg loading and interaction time. CS/nAg nanocomposites films did not show Ag⁰/Ag⁺ release in saline buffer and rat serum after exposition during 7 days. Healing process was significantly enhanced by the presence of CS/nAg nanocomposites, inducing the production of myofibloblasts, collagen remodelation, blood vessels neoformation and epidermis regeneration after 7 days of injury treatment, by means of histological and immunohistochemistry assays. The present work suggests that hydrated CS/nAg nanocomposites can be formed a mesh, improving the bacterial penetration and the contact with embedded nAg, producing complete growth inhibition after 1.5 hours. Furthermore, CS/nAg nanocomposites improve the cell tissue regeneration in thermal burn injuries induced in rats. Synthesis of antibacterial, non-toxic, and biocompatible nanocomposites can be an important issue in tissue engineering and health care applications.

Keywords: antibacterial, chitosan, healing process, nanocomposites, silver

Procedia PDF Downloads 286
2950 Shared Versus Pooled Automated Vehicles: Exploring Behavioral Intentions Towards On-Demand Automated Vehicles

Authors: Samira Hamiditehrani

Abstract:

Automated vehicles (AVs) are emerging technologies that could potentially offer a wide range of opportunities and challenges for the transportation sector. The advent of AV technology has also resulted in new business models in shared mobility services where many ride hailing and car sharing companies are developing on-demand AVs including shared automated vehicles (SAVs) and pooled automated vehicles (Pooled AVs). SAVs and Pooled AVs could provide alternative shared mobility services which encourage sustainable transport systems, mitigate traffic congestion, and reduce automobile dependency. However, the success of on-demand AVs in addressing major transportation policy issues depends on whether and how the public adopts them as regular travel modes. To identify conditions under which individuals may adopt on-demand AVs, previous studies have applied human behavior and technology acceptance theories, where Theory of Planned Behavior (TPB) has been validated and is among the most tested in on-demand AV research. In this respect, this study has three objectives: (a) to propose and validate a theoretical model for behavioral intention to use SAVs and Pooled AVs by extending the original TPB model; (b) to identify the characteristics of early adopters of SAVs, who prefer to have a shorter and private ride, versus prospective users of Pooled AVs, who choose more affordable but longer and shared trips; and (c) to investigate Canadians’ intentions to adopt on-demand AVs for regular trips. Toward this end, this study uses data from an online survey (n = 3,622) of workers or adult students (18 to 75 years old) conducted in October and November 2021 for six major Canadian metropolitan areas: Toronto, Vancouver, Ottawa, Montreal, Calgary, and Hamilton. To accomplish the goals of this study, a base bivariate ordered probit model, in which both SAV and Pooled AV adoptions are estimated as ordered dependent variables, alongside a full structural equation modeling (SEM) system are estimated. The findings of this study indicate that affective motivations such as attitude towards AV technology, perceived privacy, and subjective norms, matter more than sociodemographic and travel behavior characteristic in adopting on-demand AVs. Also, the results of second objective provide evidence that although there are a few affective motivations, such as subjective norms and having ample knowledge, that are common between early adopters of SAVs and PooledAVs, many examined motivations differ among SAV and Pooled AV adoption factors. In other words, motivations influencing intention to use on-demand AVs differ among the service types. Likewise, depending on the types of on-demand AVs, the sociodemographic characteristics of early adopters differ significantly. In general, findings paint a complex picture with respect to the application of constructs from common technology adoption models to the study of on-demand AVs. Findings from the final objective suggest that policymakers, planners, the vehicle and technology industries, and the public at large should moderate their expectations that on-demand AVs may suddenly transform the entire transportation sector. Instead, this study suggests that SAVs and Pooled AVs (when they entire the Canadian market) are likely to be adopted as supplementary mobility tools rather than substitutions for current travel modes

Keywords: automated vehicles, Canadian perception, theory of planned behavior, on-demand AVs

Procedia PDF Downloads 70
2949 Relative Influence of Self-Regulation, Emotional Intelligence, Self-Efficacy, and Goal Orientation on School Engagement among Public Secondary School Students in Ibadan, Nigeria

Authors: Ogunremi Beatrice, Oluwole David Adebayo

Abstract:

Public secondary school students are face with some challenges from the parents, government and teachers in school. Some of the challenges that arises from the parents are lack of attention and adequate communication. From the government are unavailability of useful instructional materials, competent and professionally trained teachers for each subject the students do in school. The challenges that arise from the teachers most often are mismanagement of time, inability to understand the capacity of the student and lack class management and follow up. This study investigated self-regulation, emotional intelligence, self-efficacy and goal orientation as predictors of school engagement among public secondary school students in Ibadan. A structured questionnaire was administered on 258 students from six mixed secondary schools in Ibadan. Pearson Product Moment Correlation method was used for data analysis. Four hypothesis were raised and answered, the results showed there is positive and significant relationships between school engagement among public secondary school students and each of the independent variable: Self-regulation, Emotional intelligence, Self-efficacy, Goal orientation. On the basis of these findings, it was recommended that the parents have to encourage their children on how to be goal oriented ,build their self-efficacy skill, to be self-regulated and emotionally intelligent in order to be effective in school and be able to increase their intellectual ability.

Keywords: emotional intelligence, self-efficacy, goal orientation, school engagement, self-regulation

Procedia PDF Downloads 478