Search results for: natural and anthropogenic safety

Authors: Mujahid Muhammad, Paul Kearney, Adel Aneiba

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The ability for vehicles to communicate with other vehicles (V2V), the physical (V2I) and network (V2N) infrastructures, pedestrians (V2P), etc. – collectively known as V2X (Vehicle to Everything) – will enable a broad and growing set of applications and services within the intelligent transport domain for improving road safety, alleviate traffic congestion and support autonomous driving. The telecommunication research and industry communities and standardization bodies (notably 3GPP) has finally approved in Release 14, cellular communications connectivity to support V2X communication (known as LTE – V2X). LTE – V2X system will combine simultaneous connectivity across existing LTE network infrastructures via LTE-Uu interface and direct device-to-device (D2D) communications. In order for V2X services to function effectively, a robust security mechanism is needed to ensure legal and safe interaction among authenticated V2X entities in the LTE-based V2X architecture. The characteristics of vehicular networks, and the nature of most V2X applications, which involve human safety makes it significant to protect V2X messages from attacks that can result in catastrophically wrong decisions/actions include ones affecting road safety. Attack vectors include impersonation attacks, modification, masquerading, replay, MiM attacks, and Sybil attacks. In this paper, we focus our attention on LTE-based V2X security and access control mechanisms. The current LTE-A security framework provides its own access authentication scheme, the AKA protocol for mutual authentication and other essential cryptographic operations between UEs and the network. V2N systems can leverage this protocol to achieve mutual authentication between vehicles and the mobile core network. However, this protocol experiences technical challenges, such as high signaling overhead, lack of synchronization, handover delay and potential control plane signaling overloads, as well as privacy preservation issues, which cannot satisfy the adequate security requirements for majority of LTE-based V2X services. This paper examines these challenges and points to possible ways by which they can be addressed. One possible solution, is the implementation of the distributed peer-to-peer LTE security mechanism based on the Bitcoin/Namecoin framework, to allow for security operations with minimal overhead cost, which is desirable for V2X services. The proposed architecture can ensure fast, secure and robust V2X services under LTE network while meeting V2X security requirements.

Keywords: authentication, long term evolution, security, vehicle-to-everything

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Authors: Foruzan Taheri, Seyedeh Negar Hosseinian, Katayoon Alizadeh

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The small countryside city of Shandiz, with a population of about 13.297 is located 35 km to the west of the Mashhad metropolitan. Due to Shandiz’s natural beauty, suitable climate, and its close proximity to Mashhad which is the largest city in the eastern half of the country, many people own second houses in this area. In addition to this, Shandiz hosts millions of visitors annually. Its economic role, which is parallel and complementary to Mashhad, has caused population growth, the increase of activities, and physical expansion, all of which exceed the city’s capacity. The aim of this descriptive and analytical study was to evaluate the impact of city expansion on the environment and aid in preventing further harm to the natural environment of this perimeter. Data were collected from population and housing statistics during a different period of time-based on GIS. Results show that the existence of an integrated environmental management system in order to coordinate development projects and the expansion of tourism programs that meet environmental conditions are necessary and achieving sustainable development with quality of life in this area without considering environmental limitations and capabilities cannot be sustained.

Keywords: population growth, tourism, physical development, environmental impact, Shandiz City

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Authors: Khaled Klib, Yousri Azzam, Ibrahim Maarouf

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Tourism is one of the most important and fastest growing economic activities in the world, which has a prominent role in the growth and development of countries and has become increasingly important as business and trade after the World War II. The tourism development is one of the most important aspects of urban development, which aims to plan and develop tourist attractions and improve the urban environment within cities. Tourism development has become a priority for the urban development policy of cities, particularly those which have many tourist potentials. Complementary services, such as infrastructure, roads’ networks, transportation, and communications are needed for these potentials to function properly. In order to achieve these functionalities, also a new planning for the new areas as an expansion is required, or developing and renovating the existing urban areas according to pre-prepared plans to avoid random expansion of the urban structure of the city. This paper aims to determine the tourist attractions of Al-Khomse city, by reviewing the most important tourist attractions such as the Roman city (Leptis Magna), the geographical location on the Mediterranean coast, the temperate climate and diversity of the natural environment. The paper also examines the reality of the infrastructure and tourist services in the city and its suitability to serve the tourism sector. The paper also includes a proposed for tourism development in the city as one of the city's urban expansion trends, which can guide the development strategy in the future. The paper concludes with a vision for the tourism development areas as one of the trends for urban expansion in the future. The paper also concludes tourism development will have an effective role in the growth and development of urban, economic and social, in addition to preserving the natural environment. The paper recommended the need to emphasize the role of tourism development as one of the pillars and trends for the development policy and expansion of Al-Khomse city, preservation of tourist attractions and natural resources and developing infrastructure and tourist services such as accommodation, entertainment, mobility, and accessibility.

Keywords: tourism, tourist attractions, tourism development, urban expansion

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Authors: Azad Khalid, Sifa Dogan

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Because of its persistence in conventional treatment plants and broad prevalence in water bodies, the pharmaceutical chemical carbamazepine (CBZ) has been suggested as an anthropogenic marker to evaluate water quality. This study provides a thorough examination of the origins and occurrences of CBZ in water bodies, as well as the drug's toxicological effects and laws. Given CBZ's well-documented negative consequences on the human body when used medicinally, cautious monitoring in water is advised. CBZ residues in drinking water may enter embryos and newborns via intrauterine exposure or breast-feeding, causing congenital abnormalities and/or neurodevelopmental issues over time. The insufficiency of solo solutions was shown after an in-depth technical study of traditional and sophisticated treatment technologies. Nanofiltration and reverse osmosis membranes are more successful at removing CBZ than traditional activated sludge and membrane bioreactor techniques. Recent research has shown that severe chemical cleaning, which is essential to prevent membrane fouling, may lower long-term removal efficiency. Furthermore, despite the efficacy of activated carbon adsorption and advanced oxidation processes, a few issues such as chemical cost and activated carbon renewal must be carefully examined. Individual technology constraints lead to the benefits of combined and hybrid systems, namely the heterogeneous advanced oxidation process.

Keywords: carbamazepine, occurrence, toxicity, conventical treatment, advanced oxidation process (AOPs)

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Authors: Miroslaw Wendeker, Piotr Kacejko, Mariusz Duk, Pawel Karpinski

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The research in the field of aircraft internal combustion engines is currently driven by the needs of decreasing fuel consumption and CO2 emissions, while fulfilling the level of safety. Currently, reciprocating aircraft engines are found in sports, emergency, agricultural and recreation aviation. Technically, they are most at a pre-war knowledge of the theory of operation, design and manufacturing technology, especially if compared to that high level of development of automotive engines. Typically, these engines are driven by carburetors of a quite primitive construction. At present, due to environmental requirements and dealing with a climate change, it is beneficial to develop aircraft piston engines and adopt the achievements of automotive engineering such as computer-controlled low-pressure injection, electronic ignition control and biofuels. The paper describes simulation research of the innovative power and control systems for the aircraft radial engine of high power. Installing an electronic ignition system in the radial aircraft engine is a fundamental innovative idea of this solution. Consequently, the required level of safety and better functionality as compared to the today’s plug system can be guaranteed. In this framework, this research work focuses on describing a methodology for optimizing the electronically controlled ignition system. This attempt can reduce emissions of toxic compounds as a result of lowered fuel consumption, optimized combustion and engine capability of efficient combustion of ecological fuels. New, redundant elements of the control system can improve the safety of aircraft. Consequently, the required level of safety and better functionality as compared to the today’s plug system can be guaranteed. The simulation research aimed to determine the vulnerability of the values measured (they were planned as the quantities measured by the measurement systems) to determining the optimal ignition angle (the angle of maximum torque at a given operating point). The described results covered: a) research in steady states; b) velocity ranging from 1500 to 2200 rpm (every 100 rpm); c) loading ranging from propeller power to maximum power; d) altitude ranging according to the International Standard Atmosphere from 0 to 8000 m (every 1000 m); e) fuel: automotive gasoline ES95. The three models of different types of ignition coil (different energy discharge) were studied. The analysis aimed at the optimization of the design of the innovative ignition system for an aircraft engine. The optimization involved: a) the optimization of the measurement systems; b) the optimization of actuator systems. The studies enabled the research on the vulnerability of the signals to the control of the ignition timing. Accordingly, the number and type of sensors were determined for the ignition system to achieve its optimal performance. The results confirmed the limited benefits, in terms of fuel consumption. Thus, including spark management in the optimization is mandatory to significantly decrease the fuel consumption. This work has been financed by the Polish National Centre for Research and Development, INNOLOT, under Grant Agreement No. INNOLOT/I/1/NCBR/2013.

Keywords: piston engine, radial engine, ignition system, CFD model, engine optimization

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Authors: Teagan Fink, Lynn Chong, Michael Hii, Brett Knowles

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Background: Telemedicine is a rapidly advancing field providing healthcare to patients at a distance from their treating clinician. There is a paucity of high-quality evidence detailing the safety and acceptability of telemedicine for postoperative outpatient follow-up. This randomized controlled trial – conducted prior to the COVID 19 pandemic – aimed to assess patient satisfaction and safety (as determined by readmission, reoperation and complication rates) of telephone compared to face-to-face clinic follow-up after uncomplicated general surgical procedures. Methods: Patients following uncomplicated laparoscopic appendicectomy or cholecystectomy and laparoscopic or open umbilical or inguinal hernia repairs were randomized to a telephone or face-to-face outpatient clinic follow-up. Data points including patient demographics, perioperative details and postoperative outcomes (eg. wound healing complications, pain scores, unplanned readmission to hospital and return to daily activities) were compared between groups. Patients also completed a Likert patient satisfaction survey following their consultation. Results: 103 patients were recruited over a 12-month period (21 laparoscopic appendicectomies, 65 laparoscopic cholecystectomies, nine open umbilical hernia repairs, six laparoscopic inguinal hernia repairs and two laparoscopic umbilical hernia repairs). Baseline patient demographics and operative interventions were the same in both groups. Patient or clinician-reported concerns on postoperative pain, use of analgesia, wound healing complications and return to daily activities at clinic follow-up were not significantly different between the two groups. Of the 58 patients randomized to the telemedicine arm, 40% reported high and 60% reported very high patient satisfaction. Telemedicine clinic mean consultation times were significantly shorter than face-to-face consultation times (telemedicine 10.3 +/- 7.2 minutes, face-to-face 19.2 +/- 23.8 minutes, p-value = 0.014). Rates of failing to attend clinic were not significantly different (telemedicine 3%, control 6%). There was no increased rate of postoperative complications in patients followed up by telemedicine compared to in-person. There were no unplanned readmissions, return to theatre, or mortalities in this study. Conclusion: Telemedicine follow-up of patients undergoing uncomplicated general surgery is safe and does not result in any missed diagnosis or higher rates of complications. Telemedicine provides high patient satisfaction and steps to implement this modality in inpatient care should be undertaken.

Keywords: general surgery, telemedicine, patient satisfaction, patient safety

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Authors: Divya Haridas, C. B. Sobhan

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Laser interferometric methods have been utilized for the measurement of natural convection heat transfer from a heated vertical flat plate, in the investigation presented here. The study mainly aims at comparing two different fringe orientations in the wedge fringe setting of Mach-Zehnder interferometer (MZI), used for the measurements. The interference fringes are set in horizontal and vertical orientations with respect to the heated surface, and two different fringe analysis methods, namely the stepping method and the method proposed by Naylor and Duarte, are used to obtain the heat transfer coefficients. The experimental system is benchmarked with theoretical results, thus validating its reliability in heat transfer measurements. The interference fringe patterns are analyzed digitally using MATLAB 7 and MOTIC Plus softwares, which ensure improved efficiency in fringe analysis, hence reducing the errors associated with conventional fringe tracing. The work also discuss the relative merits and limitations of the two methods used.

Keywords: Mach-Zehnder interferometer (MZI), natural convection, Naylor method, Vertical Flat Plate

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Authors: Ghulam Abbas, Ikramul Haq, Ghulam Ghouse

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Bread wheat Triticum aestivum L. (Poaceae) is the major source of the staple food for a number of countries of the world including Pakistan. Since it is the staple food of the country, it has been desired, and efforts have been made, that it does not undergo application of pesticides to ensure the food safety. Luckily, wheat does not face a serious threat of insect pests, in ecological conditions of Pakistan, except aphids and armyworm which infest the wheat prior to maturity. It has been observed that almost 5 species of aphid have been reported to attack wheat ie. Ropalosiphum maidi, R. Padi, Schizaphis graminum, Diuraphis noxia, and Sitibion miscanthi but due to natural rise in temperature in terminal season of wheat, the population of aphid gradually decreases and wheat has a safe escape from its infestation. In case, mild temperatures 15ºC to 30ºC prolong, the infestation of aphids also prolongs and it can severely damage wheat in patches, and it has potential to substantially reduce the yield of wheat in infested patch. In years 2013, 2014, and 2015 the studies were undertaken to determine the potential of damage caused by aphid complex in 10 fields in infested patches. The damage caused by aphid complex was calculated on the basis of 1000 grain weight of wheat grains taken from the infested patch and were compared with 1000 grain weight of the healthy plants of the same fields. It was observed that there was 26 to 42% decrease in the weight of grain in infested patches. This patch also escaped from general harvesting by combine harvester and enhanced the loss 13 to 46%. The quality of the wheat straw was also reduced and its acceptance to the animals was also affected up to 50 to 100%. Moreover, the population of naturally existing beneficial fauna was recorded and factors promoting establishment and manipulation of beneficial fauna were studied and analysed.

Keywords: Triticum aestivum, wheat, Pakistan, beneficial fauna, aphid complex

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Authors: Jinhoa Lee

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The relationships between environmental quality, energy use and economic output have created growing attention over the past decades among researchers and policy makers. Focusing on the empirical aspects of the role of carbon dioxide (CO2) emissions and energy use in affecting the economic output, this paper is an effort to fulfill the gap in a comprehensive case study at a country level using modern econometric techniques. To achieve the goal, this country-specific study examines the short-run and long-run relationships among energy consumption (using disaggregated energy sources: crude oil, coal, natural gas, electricity), CO2 emissions and gross domestic product (GDP) for Egypt using time series analysis from the year 1980-2010. To investigate the relationships between the variables, this paper employs the Augmented Dickey-Fuller (ADF) test for stationarity, Johansen maximum likelihood method for co-integration and a Vector Error Correction Model (VECM) for both short- and long-run causality among the research variables for the sample. The long-run equilibrium in the VECM suggests some negative impacts of the CO2 emissions and the coal and natural gas use on the GDP. Conversely, a positive long-run causality from the electricity consumption to the GDP is found to be significant in Egypt during the period. In the short-run, some positive unidirectional causalities exist, running from the coal consumption to the GDP, and the CO2 emissions and the natural gas use. Further, the GDP and the electricity use are positively influenced by the consumption of petroleum products and the direct combustion of crude oil. Overall, the results support arguments that there are relationships among environmental quality, energy use, and economic output in both the short term and long term; however, the effects may differ due to the sources of energy, such as in the case of Egypt for the period of 1980-2010.

Keywords: CO2 emissions, Egypt, energy consumption, GDP, time series analysis

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Authors: Alvarez Barrantes, Robert Dorrell, Christopher Hackney, Anne Baar, Roberto Fernandez, Daniel Parsons

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Microplastic particles entering fluvial environments are deposited with natural sediments. Their settling properties can change by the absorption or adsorption of contaminants, organic matter, and organisms. These deposits include positively, neutrally, and negatively buoyant particles. This study aims to understand how plastic particles of different densities interact with natural sediments as they settle and how they are stored within the sediment deposit. The results of this study contribute to a better understanding of the deposition of microplastic particles and associated pollution in rivers. A set of 48 experiments was designed to investigate the settling process of microplastic particles in freshwater. The experimental work describes the vertical variation of cohesive and/or non-cohesive sediment versus microplastic densities in deposited sediment. The experiment consisted of adding microplastic particles, sediment, and water in a waterproof carton tube of a height of 24 cm and a diameter of 5 cm. The plastic selected is positively, neutrally, and negatively buoyant. The sediments consist of sand and clay with four different concentrations. The mixture of materials was shaken until is thoroughly mixed and left to settle for 24 hours. After the settlement, the tubes were frozen at -20 °C to be able to cut them and measure the thickness of the deposits and analyze the sediment and plastic distribution. The most representative experiments were repeated in a glass tube of the same size; to analyse the influences of current flows and depositional process. Finally, the glass tube experiments were used to study organic materials adsorption in plastic, settling the sample for four months. Defined microplastic layers were identified as the density of the plastic change. Preliminary results show that most of the positive buoyancy particles floated, neutral buoyancy particles form a layer above the sediment and negative buoyancy particles mixed with the sediment. The vertical grain size distribution of the deposits was analysed to determine deposition variation with and without plastic. It is expected that the positively buoyant particles are trapped in the sediment by the currents flows and sink due to organic material adsorption. Finally, the experiments will explain how microplastic particles, including positively buoyant ones, are stored in natural sediment deposits.

Keywords: microplastic adsorption process, microplastic deposition in natural sediment, microplastic pollution in rivers, storages of positive buoyancy microplastic particles

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Authors: T. Ghatauray, J. Ingram, P. Holborn

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The transition from a ‘carbon rich’ fossil fuel dependent to a ‘sustainable’ and ‘renewable’ hydrogen based society will see the deployment of hydrogen fuel cells (HFC) in transport applications and in the generation of heat and power for buildings, as part of a decentralised power network. Many deployments will be low power HFCs for domestic combined heat and power (CHP) and commercial ‘transportable’ HFCs for environmental situations, such as lighting and telephone towers. For broad commercialisation of small fuel cells to be achieved there needs to be significant confidence in their safety in both domestic and environmental applications. Low power HFCs are housed in protective steel enclosures. Standard enclosures have plain rectangular ventilation openings intended for thermal management of electronics and not the dispersion of a buoyant gas. Degradation of the HFC or supply pipework in use could lead to a low-level leak and a build-up of hydrogen gas in the enclosure. Hydrogen’s wide flammable range (4-75%) is a significant safety concern, with ineffective enclosure ventilation having the potential to cause flammable mixtures to develop with the risk of explosion. Mechanical ventilation is effective at managing enclosure hydrogen concentrations, but drains HFC power and is vulnerable to failure. This is undesirable in low power and remote installations and reliable passive ventilation systems are preferred. Passive ventilation depends upon buoyancy driven flow, with the size, shape and position of ventilation openings critical for producing predictable flows and maintaining low buoyant gas concentrations. With environmentally sited enclosures, ventilation openings with pressed horizontal and angled louvres are preferred to protect the HFC and electronics inside. There is an economic cost to adding louvres, but also a safety concern. A question arises over whether the use of pressed louvre vents impairs enclosure passive ventilation performance, when compared to same opening area plain vents. Comparison small enclosure (0.144m³) tests of same opening area pressed louvre and plain vents were undertaken. A displacement ventilation arrangement was incorporated into the enclosure with opposing upper and lower ventilation openings. A range of vent areas were tested. Helium (used as a safe analogue for hydrogen) was released from a 4mm nozzle at the base of the enclosure to simulate a hydrogen leak at leak rates from 1 to 10 lpm. Helium sensors were used to record concentrations at eight heights in the enclosure. The enclosure was otherwise empty. These tests determined that the use of pressed and angled louvre ventilation openings on the enclosure impaired the passive ventilation flow and increased helium concentrations in the enclosure. High-level stratified buoyant gas layers were also found to be deeper than with plain vent openings and were within the flammable range. The presence of gas within the flammable range is of concern, particularly as the addition of the fuel cell and electronics in the enclosure would further reduce the available volume and increase concentrations. The opening area of louvre vents would need to be greater than equivalent plain vents to achieve comparable ventilation flows or alternative schemes would need to be considered.

Keywords: enclosure, fuel cell, helium, hydrogen safety, louvre vent, passive ventilation

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Authors: Radhika Ramanchi

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The oil market during 2014-2015 in India with large price fluctuations is very confusing to individual investor. The drop in oil prices supported stocks of some oil marketing companies (OMCs) like Bharat Petroleum Corporation, Hindustan Petroleum Corporation (HPCL) and Indian Oil Corporation etc their shares rose 84.74%, 128.63% and 59.16%, respectively. Lower oil prices, and lower current account, a smaller subsidy burden are the reasons for outperformance. On the other hand, lower crude prices giving downward pressure on upstream companies like Oil and Natural Gas Corp. Ltd (ONGC) and Reliance Petroleum (RIL) Oil India Ltd (OIL). Not having clarity on a subsidy sharing mechanism is the reason for downward trend on these stocks. Shares of ONGC and RIL have underperformed so far in 2015. When the oil price fall profits of the companies will effect, generate less money and may cut their dividends in Long run. In this situation this paper objective is to study investment strategies in oil marketing companies, by applying CAPM and Security Market Line.

Keywords: petrol industry, price fluctuations, sharp single index model, SML, Markowitz model

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

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

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

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Authors: Jo, Eui Chang, Shin, Heekang, Mun, A. Young , Kim, Hong Kyu

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Regarding change on population and family structure in Korea after the 1980s, there has been a rapid change of low fertility, graying and increase of single household that cannot be found in any other parts of the world. With the result of total population residence by the National Statistical Office, Korea will hold 52,160,065 people in 2030 and reduction is predicted and from 2025 people above the age of 65 will take 20% of the total population, which means the entry of a super aging society. Also, average number in a family will be 2.71 in 2015 and decrease to 2.33 in 2035. On the other hand, proportion of single and two person household will be 53.7% in 2015 and it will increase up to 68.4% in 2035. Old population will increase greatly, single and two person household will take 2/3 of the total households. Delphi research was processed in 3 steps on 40 professionals about the importance and changing factors of residential environment of apartment followed by the change of population structure. For interior plan, space variety, variability, safety, convenient installation, eco-friendly installation, and IT installation were important factors for construction plan, plan on aged and single households, convenient installation, safety installation, eco-friendly installation for subdivision plan, education/child care facility, parks/gymnasium facility, community facility, and accessibility of transportation were predicted as important factors.

Keywords: change of population structure, super-graying, change of residential environment of apartment, single household, interior plan, construction plan, subdivision plan, Delphi research

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Authors: A. Abdullah, N. Faghih Mirzaei, S. Hany Haron

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Neighbourhood environment walkability on reported physical activity (PA) levels of students of Universiti Sains Malaysia (USM) in Malaysia. Compared with previous generations, today’s young people spend less time playing outdoors and have lower participation rates in PA. Research suggests that negative perceptions of neighbourhood walkability may be a potential barrier to adolescents’ PA. The sample consisted of 200 USM students (to 24 years old) who live outside of the main campus and engage in PA in sport halls and sport fields of USM. The data were analysed using the t-test, binary logistic regression, and discriminant analysis techniques. The present study found that youth PA was affected by neighbourhood environment walkability factors, including neighbourhood infrastructures, neighbourhood safety (crime), and recreation facilities, as well as street characteristics and neighbourhood design variables such as facades of sidewalks, roadside trees, green spaces, and aesthetics. The finding also illustrated that active students were influenced by street connectivity, neighbourhood infrastructures, recreation facilities, facades of sidewalks, and aesthetics, whereas students in the less active group were affected by access to destinations, neighbourhood safety (crime), and roadside trees and green spaces for their PAs. These results report which factors of built environments have more effect on youth PA and they message to the public to create more awareness about the benefits of PA on youth health.

Keywords: fear of crime, neighbourhood built environment, physical activities, street characteristics design

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Authors: Kittipon Chittanukul, Chayut Bureethan, Chutimon Piromyaporn

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In Thailand, the natural gas pipeline system requires the preparation of an Environmental Impact Assessment (EIA) report for approval by the relevant agency, the Office of Natural Resources and Environmental Policy and Planning (ONEP), in the pre-construction stage. As of December 2022, PTT has a lot of gas pipeline system spanning around the country. Our experience has shown that the EIA is a significant part of the project plan. In 2011, There was a catastrophic flood in multiple areas of Thailand. It destroyed lives and properties. This event is still in Thai people’s mind. Furthermore, rainfall has been increasing for three consecutive years (2020-2022). Moreover, municipalities are situated in low land river basin and tropical rainfall zone. So many areas still suffer from flooding. Especially in 2022, there will be a 60% increase in water demand compared to the previous year. Therefore, all activities will take into account the quality of the receiving water. The above information emphasizes water and wastewater management are significant in EIA report. PTT has accumulated a large number of lessons learned in water and wastewater management. Our pipeline system execution is composed of EIA stage, construction stage, and operation and maintenance phase. We provide practical Information on water and wastewater management to enhance the EIA process for the pipeline system. The examples of lessons learned in water and wastewater management include techniques to address water and wastewater impact throughout the overall pipelines systems, mitigation measures and monitoring results of these measures. This practical information will alleviate the anxiety of the ONEP committee when approving the EIA report and will build trust among stakeholders in the vicinity of the gas pipeline system area.

Keywords: environmental impact assessment, gas pipeline system, low land basin, high risk flooding area, mitigation measure

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Authors: Carlos M. Goncalves, Luisa Duarte, Teresa Cartaxo

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The aim of this work was to understand the reasons behind the underutilization of electroconvulsive therapy (ECT) in the younger population and raise possible solutions. We conducted a non-systematic review of literature throughout a search on PubMed, using the terms ‘children’, ‘adolescents’ and ‘electroconvulsive’, ‘therapy’. Candidate articles written in languages other than English were excluded. Articles were selected according to title and/or abstract’s content relevance, resulting in a total of 5 articles. ECT is a recognized effective treatment in adults for several psychiatric conditions. As in adults, ECT in children and adolescents is proven most beneficial in the treatment of severe mood disorders, catatonia, and, to a lesser extent, schizophrenia. ECT in adults has also been used to treat autism’s self-injurious behaviours, Tourette’s syndrome and resistant first-episode schizophrenia disorder. Despite growing evidence on its safety and effectiveness in children and adolescents, like those found in adults, ECT remains a controversial and underused treatment in patients this age, even when it is clearly indicated. There are various possible reasons to this; limited awareness among professionals (lack of knowledge and experience among child psychiatrists), stigmatic public opinion (despite positive feedback from patients and families, there is an unfavourable and inaccurate representation in the media, contributing to a negative public opinion), legal restrictions and ethical controversies (restrictive regulations such as a minimum age for administration), lack of randomized trials (the currently available studies are retrospective, with small size samples, and most of the publications are either case reports or case series). This shows the need to raise awareness and knowledge, not only for mental health professionals, but also to the general population, through the media, regarding indications, methods and safety of ECT in order to provide reliable information to the patient and families. Large-scale longitudinal studies are also useful to further demonstrate the efficacy and safety of ECT and can aid in the formulation of algorithms and guidelines as without these changes, the availability of ECT to the younger population will remain restricted by regulations and social stigma. In conclusion, these results highlight that lack of adequate knowledge and accurate information are the most important factors behind the underutilization of ECT in younger population. Mental healthcare professionals occupy a cornerstone position; if data is given by a well-informed healthcare professional instead of the media, general population (including patients and their families) will probably regard the procedure in a more favourable way. So, the starting point should be to improve health care professional’s knowledge and experience on this choice of treatment.

Keywords: adolescents, children, electroconvulsive, therapy

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Authors: Manoj Sarda, Abhishek Agarwal, Juhi Kaushik, Vatsal Sanjay, Arup Kumar Das

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Railways in India remain primary mode of transport having one of the largest networks in the world and catering to billions of transits yearly. Catastrophic economic damage and loss to life is encountered over the past few decades due to fire to locomotives. Study of fire dynamics and fire propagation plays an important role in evacuation planning and reducing losses. Simulation based study of propagation of fire and soot inside an air conditioned coach of Indian locomotive is done in this paper. Finite difference based solver, Fire Dynamic Simulator (FDS) version 6 has been used for analysis. A single air conditioned 3 tier coupe closed to ambient surroundings by glass windows having occupancy for 8 people is the basic unit of the domain. A system of three such coupes combined is taken to be fundamental unit for the entire study to resemble effect to an entire coach. Analysis of flame and soot contours and concentrations is done corresponding to variations in heat release rate per unit volume (HRRPUA) of fire source, variations in conditioned air velocity being circulated inside coupes by vents and an alternate fire initiation and propagation mechanism via ducts. Quantitative results of fractional area in top and front view of the three coupes under fire and smoke are obtained using MATLAB (IMT). Present simulations and its findings will be useful for organizations like Commission of Railway Safety and others in designing and implementing safety and evacuation measures.

Keywords: air conditioned coaches, fire propagation, flame contour, soot flow, train fire

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Authors: A. M. Merino-Lechuga, A. González-Caro, D. Suescum-Morales, E. Fernández-Ledesma, J. R. Jiménez, J. M. Fernández-Rodriguez

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Since the mid-19th century, the boom in the economy and industry has grown exponentially. This has led to an increase in pollution due to rising Greenhouse Gas (GHG) emissions and the accumulation of waste, leading to an increasingly imminent future scarcity of raw materials and natural resources. Carbon dioxide (CO₂) is one of the primary greenhouse gases, accounting for up to 55% of Greenhouse Gas (GHG) emissions. The manufacturing of construction materials generates approximately 73% of CO₂ emissions, with Portland cement production contributing to 41% of this figure. Hence, there is scientific and social alarm regarding the carbon footprint of construction materials and their influence on climate change. Carbonation of concrete is a natural process whereby CO₂ from the environment penetrates the material, primarily through pores and microcracks. Once inside, carbon dioxide reacts with calcium hydroxide (Ca(OH)2) and/or CSH, yielding calcium carbonates (CaCO3) and silica gel. Consequently, construction materials act as carbon sinks. This research investigated the effect of accelerated carbonation on the physical, mechanical, and chemical properties of two types of non-structural vibrated concrete pavers (conventional and draining) made from natural aggregates and two types of recycled aggregates from construction and demolition waste (CDW). Natural aggregates were replaced by recycled aggregates using a volumetric substitution method, and the CO₂ capture capacity was calculated. Two curing environments were utilized: a carbonation chamber with 5% CO₂ and a standard climatic chamber with atmospheric CO₂ concentration. Additionally, the effect of curing times of 1, 3, 7, 14, and 28 days on concrete properties was analyzed. Accelerated carbonation in-creased the apparent dry density, reduced water-accessible porosity, improved compressive strength, and decreased setting time to achieve greater mechanical strength. The maximum CO₂ capture ratio was achieved with the use of recycled concrete aggregate (52.52 kg/t) in the draining paver. Accelerated carbonation conditions led to a 525% increase in carbon capture compared to curing under atmospheric conditions. Accelerated carbonation of cement-based products containing recycled aggregates from construction and demolition waste is a promising technology for CO₂ capture and utilization, offering a means to mitigate the effects of climate change and promote the new paradigm of circular economy.

Keywords: accelerated carbonation, CO₂ curing, CO₂ uptake and construction and demolition waste., circular economy

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Authors: Sezer Kefeli, Sertaç Arslan

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Supercavitation is a pressure dependent process which gives opportunity to eliminate the wetted surface effects on the underwater vehicle due to the differences of viscosity and velocity effects between liquid (freestream) and gas phase. Cavitation process occurs depending on rapid pressure drop or temperature rising in liquid phase. In this paper, pressure based cavitation is investigated due to the fact that is encountered in the underwater world, generally. Basically, this vapor-filled pressure based cavities are unstable and harmful for any underwater vehicle because these cavities (bubbles or voids) lead to intense shock waves while collapsing. On the other hand, supercavitation is a desired and stabilized phenomena than general pressure based cavitation. Supercavitation phenomena offers the idea of minimizing form drag, and thus supercavitating vehicles are revived. When proper circumstances are set up, which are either increasing the operating speed of the underwater vehicle or decreasing the pressure difference between free stream and artificial pressure, the continuity of the supercavitation is obtainable. There are 2 types of supercavitation to obtain stable and continuous supercavitation, and these are called as natural and artificial supercavitation. In order to generate natural supercavitation, various mechanical structures are discovered, which are called as cavitators. In literature, a lot of cavitator types are studied either experimentally or numerically on a CFD platforms with intent to observe natural supercavitation since the 1900s. In this paper, firstly, experimental results are obtained, and trend lines are generated based on supercavitation parameters in terms of cavitation number (), form drag coefficientC_D, dimensionless cavity diameter (d_m/d_c), and length (L_c/d_c). After that, natural cavitation verification studies are carried out for disk and cone shape cavitators. In addition, supercavitation parameters are numerically analyzed at different operating conditions, and CFD results are fitted into trend lines of experimental results. The aims of this paper are to generate one generally accepted drag coefficient equation for disk and cone cavitators at different cavitator half angle and investigation of the supercavitation parameters with respect to cavitation number. Moreover, 165 CFD analysis are performed at different cavitation numbers on FLUENT version 21R2. Five different cavitator types are modeled on SCDM with respect tocavitator’s half angles. After that, CFD database is generated depending on numerical results, and new trend lines are generated based on supercavitation parameters. These trend lines are compared with experimental results. Finally, the generally accepted drag coefficient equation and equations of supercavitation parameters are generated.

Keywords: cavity envelope, CFD, high speed underwater vehicles, supercavitation, supercavitating flows, supercavitation parameters, drag reduction, viscous force elimination, natural cavitation verification

Procedia PDF Downloads 131

Authors: Ismayanti Magfirah, Sartohadi Junun, Samodra Guruh

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Landslides are one of the most frequent and devastating natural disasters in Indonesia. Many studies have been conducted regarding this phenomenon. However, there is a lack of attention in the landslide inventory mapping. The natural condition (dense forest area) and the limited human and economic resources are some of the major problems in building landslide inventory in Indonesia. Considering the importance of landslide inventory data in susceptibility, hazard, and risk analysis, it is essential to generate landslide inventory based on available resources. In order to achieve this, the first thing we have to do is identify the landslides' location. The presence of Sentinel-1A and Sentinel-2A data gives new insights into land monitoring investigation. The free access, high spatial resolution, and short revisit time, make the data become one of the most trending open sources data used in landslide mapping. Sentinel-1A and Sentinel-2A data have been used broadly for landslide detection and landuse/landcover mapping. This study aims to generate landslide map by integrating Sentinel-1A and Sentinel-2A data use change detection method. The result will be validated by field investigation to make preliminary landslide inventory in the study area.

Keywords: change detection method, landslide inventory mapping, Sentinel-1A, Sentinel-2A

Procedia PDF Downloads 171

Authors: Paulo Teodoro De Luna Carada, Toru Fujii, Kazuya Okubo

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Natural fibers have wide variety of uses (e.g., rope, paper, and building materials). One specific application of it is in the field of composite materials (i.e., green composites). Huge amount of research are being done in this field due to rising concerns in the harmful effects of synthetic materials to the environment. There are several natural fibers used in this field, one of which can be extracted from a plant called kenaf (Hibiscus cannabinus L.). Kenaf fiber is regarded as a good alternative because the plant is easy to grow and the fiber is easy to extract. Additionally, it has good properties. Treatments, which are classified as mechanical or chemical in nature, can be done in order to improve the properties of the fiber. The aim of this study is to assess the effects of heat treatment in kenaf fiber. It specifically aims to observe the effect in the tensile strength and modulus of the fiber. Kenaf fiber bundles with an average diameter of at most 100μm was used for this purpose. Heat treatment was done using a constant temperature oven with the following heating temperatures: (1) 160̊C, (2) 180̊C, and (3) 200̊C for a duration of one hour. As a basis for comparison, tensile test was first done to kenaf fibers without any heat treatment. For every heating temperature, three groups of samples were prepared. Two groups of which were for doing tensile test (one group was tested right after heat treatment while the remaining group was kept inside a closed container with relative humidity of at least 95% for two days). The third group was used to observe how much moisture the treated fiber will absorb when it is enclosed in a high moisture environment for two days. The results showed that kenaf fiber can retain its tensile strength when heated up to a temperature of 160̊C. However, when heated at a temperature of about 180̊C or higher, the tensile strength decreases significantly. The same behavior was observed for the tensile modulus of the fiber. Additionally, the fibers which were stored for two days absorbed nearly the same amount of moisture (about 20% of the dried weight) regardless of the heating temperature. Heat treatment might have damaged the fiber in some way. Additional test was done in order to see if the damage due to heat treatment is attributed to changes in the viscoelastic property of the fiber. The findings showed that kenaf fibers can be heated for at most 160̊C to attain good tensile strength and modulus. Additionally, heating the fiber at high temperature (>180̊C) causes changes in its viscoelastic property. The results of this study is significant for processes which requires heat treatment not only in kenaf fiber but might also be helpful for natural fibers in general.

Keywords: heat treatment, kenaf fiber, natural fiber, mechanical properties

Procedia PDF Downloads 353

Authors: A. Robak, M. Pieńko, E. Błazik-Borowa, J. Bęc, I. Szer

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The analyzes and classifications presented in the article were based on the research carried out in year 2016 and 2017 on a group of nearly one hundred scaffoldings assembled and used on construction sites in different parts of Poland. During scaffolding selection process efforts were made to maintain diversification in terms of parameters such as scaffolding size, investment size, type of investment, location and nature of conducted works. This resulted in the research being carried out on scaffoldings used for church renovation in a small town or attached to the facades of classic apartment blocks, as well as on scaffoldings used during construction of skyscrapers or facilities of the largest power plants. This variety allows to formulate general conclusions about the technical condition of used frame scaffoldings. Exploitation damages of the frame scaffolding elements were divided into three groups. The first group includes damages to the main structural components, which reduce the strength of the scaffolding elements and hence the whole structure. The qualitative analysis of these damages was made on the basis of numerical models that take into account the geometry of the damage and on the basis of computational nonlinear static analyzes. The second group focuses on exploitation damages such as the lack of a pin on the guardrail bolt which may cause an imminent threat to people using scaffolding. These are local damages that do not affect the bearing capacity and stability of the whole structure but are very important for safe use. The last group consider damages that reduce only aesthetic values and do not have direct impact on bearing capacity and safety of use. Apart from qualitative analyzes the article will present quantitative analyzes showing how frequently given type of damage occurs.

Keywords: scaffolding, damage, safety, numerical analysis

Procedia PDF Downloads 259

Authors: Tiago do Carmo Nogueira, Cássio Dener Noronha Vinhal, Gélson da Cruz Júnior, Matheus Rudolfo Diedrich Ullmann

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Generating automatic image descriptions through natural language is a challenging task. Image captioning is a task that consistently describes an image by combining computer vision and natural language processing techniques. To accomplish this task, cutting-edge models use encoder-decoder structures. Thus, Convolutional Neural Networks (CNN) are used to extract the characteristics of the images, and Recurrent Neural Networks (RNN) generate the descriptive sentences of the images. However, cutting-edge approaches still suffer from problems of generating incorrect captions and accumulating errors in the decoders. To solve this problem, we propose a model based on the encoder-decoder structure, introducing a module that generates the weights according to the importance of the word to form the sentence, using the part-of-speech (PoS). Thus, the results demonstrate that our model surpasses state-of-the-art models.

Keywords: gated recurrent units, caption generation, convolutional neural network, part-of-speech

Procedia PDF Downloads 102

Authors: Mark McGuire, Eric Shannon, John Parmigiani

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Timber harvesting increasingly involves mechanized equipment. This has increased the efficiency of harvesting, but has also introduced worker-safety concerns. One such concern arises from the use of harvesters. During operation, harvesters subject saw chain to large dynamic mechanical stresses. These stresses can, under certain conditions, cause the saw chain to fracture. The high speed of harvester saw chain can cause the resulting open chain loop to fracture a second time due to the dynamic loads placed upon it as it travels through space. If a second fracture occurs, it can result in a projectile consisting of one-to-several chain links. This projectile is referred to as a chain shot. It has speeds similar to a bullet but typically has greater mass and is a significant safety concern. Numerous examples exist of chain shots penetrating bullet-proof barriers and causing severe injury and death. Improved harvester-cab barriers can help prevent injury however a comprehensive scientific understanding of chain shot is required to consistently reduce or prevent it. Obtaining this understanding requires a test machine with the capability to cause chain shot to occur under carefully controlled conditions and accurately measure the response. Worldwide few such test machine exist. Those that do focus on validating the ability of barriers to withstand a chain shot impact rather than obtaining a scientific understanding of the chain shot event itself. The purpose of this paper is to describe the design, fabrication, and use of a test machine capable of a comprehensive scientific investigation of chain shot. The capabilities of this machine are to test all commercially-available saw chains and bars at chain tensions and speeds meeting and exceeding those typically encountered in harvester use and accurately measure the corresponding key technical parameters. The test machine was constructed inside of a standard shipping container. This provides space for both an operator station and a test chamber. In order to contain the chain shot under any possible test conditions, the test chamber was lined with a base layer of AR500 steel followed by an overlay of HDPE. To accommodate varying bar orientations and fracture-initiation sites, the entire saw chain drive unit and bar mounting system is modular and capable of being located anywhere in the test chamber. The drive unit consists of a high-speed electric motor with a flywheel. Standard Ponsse harvester head components are used to bar mounting and chain tensioning. Chain lubrication is provided by a separate peristaltic pump. Chain fracture is initiated through ISO standard 11837. Measure parameters include shaft speed, motor vibration, bearing temperatures, motor temperature, motor current draw, hydraulic fluid pressure, chain force at fracture, and high-speed camera images. Results show that the machine is capable of consistently causing chain shot. Measurement output shows fracture location and the force associated with fracture as a function of saw chain speed and tension. Use of this machine will result in a scientific understanding of chain shot and consequently improved products and greater harvester operator safety.

Keywords: chain shot, safety, testing, timber harvesters

Procedia PDF Downloads 152

Authors: Hajar Zarei, AliAkbar Zarenejadatashgah, Vuk Uskoković, Hiroshi Watabe

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The reactive oxygen species (ROS) generated by radiation in nuclear diagnostic imaging and radiotherapy could damage the structure of the proteins in noncancerous cells surrounding the tumor. The critical factor in many age-related diseases, such as Alzheimer, Parkinson, or Huntington diseases, is the oxidation of proteins by the ROS as molecular triggers of the given pathologies. Our studies by spectroscopic experiments showed doses close to therapeutic ones (1 to 5 Gy) could lead to changes of secondary and tertiary structures in BSA protein macromolecule as a protein model as well as the aggregation of polypeptide chain but without the fragmentation. For this reason, we investigated the radioprotective effects of natural (vitamin C and E) and synthetic materials (CNPs and FIOMPs) on the structural changes in BSA protein induced by gamma irradiation at a therapeutic dose (3Gy). In the presence of both vitamins and synthetic materials, the spectroscopic studies revealed that irradiated BSA was protected from the structural changes caused by ROS, according to in vitro research. The radioprotective property of CNPs and FIOMPs arises from enzyme mimetic activities (catalase, superoxide dismutase, and peroxidase) and their antioxidant capability against hydroxyl radicals. In the case of FIOMPs, a porous structure also leads to increased ROS recombination with each other in the same radiolytic track and subsequently decreased encounters with BSA. The hydrophilicity of vitamin C resulted in the major scavenging of ROS in the solvent, whereas hydrophobic vitamin E localized on the nonpolar patches of the BSA surface, where it did not only neutralize them thanks to the moderate BSA binding constant but also formed a barrier for diffusing ROS. To the best of our knowledge, there has been a persistent lack of studies investigating the radioactive effect of mentioned materials on proteins. Therefore, the results of our studies can open a new widow for application of these common dietary ingredients and new synthetic NPs in improving the safety of radiotherapy.

Keywords: reactive oxygen species, spectroscopy, bovine serum albumin, gamma radiation, radioprotection

Procedia PDF Downloads 86

Authors: Ji-Seok Koo, Hee‑Yong Kwon, Hui-Young Yun, Kyung-Hui Wang, Youn-Seo Koo

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This paper presents a forecasting system for PM2.5 levels in Seoul, South Korea, leveraging a combination of chemical transport modeling and ConvLSTM-DNN machine learning technology. Exposure to PM2.5 has known detrimental impacts on public health, making its prediction crucial for establishing preventive measures. Existing forecasting models, like the Community Multiscale Air Quality (CMAQ) and Weather Research and Forecasting (WRF), are hindered by their reliance on uncertain input data, such as anthropogenic emissions and meteorological patterns, as well as certain intrinsic model limitations. The system we've developed specifically addresses these issues by integrating machine learning and using carefully selected input features that account for local and distant sources of PM2.5. In South Korea, the PM2.5 concentration is greatly influenced by both local emissions and long-range transport from China, and our model effectively captures these spatial and temporal dynamics. Our PM2.5 prediction system combines the strengths of advanced hybrid machine learning algorithms, convLSTM and DNN, to improve upon the limitations of the traditional CMAQ model. Data used in the system include forecasted information from CMAQ and WRF models, along with actual PM2.5 concentration and weather variable data from monitoring stations in China and South Korea. The system was implemented specifically for Seoul's PM2.5 forecasting.

Keywords: PM2.5 forecast, machine learning, convLSTM, DNN

Procedia PDF Downloads 54

Authors: Bryony Pound

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This study investigated how views of green or urban space affect learning performance. It provides evidence of the value of visual access to greenspace in work and learning environments, and builds on the extensive research into the cognitive and learning-related benefits of access to green and natural spaces, particularly in learning environments. It demonstrates that benefits of visual access to natural spaces whilst learning can produce statistically significant faster responses than those facing urban views after only 5 minutes. The primary hypothesis of this research was that a greenspace view would improve short-term learning. Participants were randomly assigned to either a view of parkland or of urban buildings from the same room. They completed a psychological test of two stages. The first stage consisted of a presentation of words from eight different categories (four manmade and four natural). Following this a 2.5 minute break was given; participants were not prompted to look out of the window, but all were observed doing so. The second stage of the test involved a word recognition/false memory test of three types. Type 1 was presented words from each category; Type 2 was non-presented words from those same categories; and Type 3 was non-presented words from different categories. Participants were asked to respond with whether they thought they had seen the words before or not. Accuracy of responses and reaction times were recorded. The key finding was that reaction times for Type 2 words (highest difficulty) were significantly different between urban and green view conditions. Those with an urban view had slower reaction times for these words, so a view of greenspace resulted in better information retrieval for word and false memory recognition. Importantly, this difference was found after only 5 minutes of exposure to either view, during winter, and with a sample size of only 26. Greenspace views improve performance in a learning task. This provides a case for better visual access to greenspace in work and learning environments.

Keywords: benefits, greenspace, learning, restoration

Procedia PDF Downloads 127

Authors: Shahril Anuar Bahari, Mohd Azrie Mohd Kepli, Mohd Ariff Jamaludin, Kamarulzaman Nordin, Mohamad Jani Saad

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Formaldehyde release from wood-based panel composites can be very toxicity and may increase the risk of human health as well as environmental problems. A new bio-composites product without synthetic adhesive or resin is possible to be developed in order to reduce these problems. Apart from formaldehyde release, adhesive is also considered to be expensive, especially in the manufacturing of composite products. Natural bonded composites can be termed as a panel product composed with any type of cellulosic materials without the addition of synthetic resins. It is composed with chemical content activation in the cellulosic materials. Pulp and paper making method (chemical pulping) was used as a general guide in the composites manufacturing. This method will also generally reduce the manufacturing cost and the risk of formaldehyde emission and has potential to be used as an alternative technology in fiber composites industries. In this study, the natural bonded bamboo fiber composite was produced from virgin Malaysian bamboo fiber (Bambusa vulgaris). The bamboo culms were chipped and digested into fiber using this pulping method. The black liquor collected from the pulping process was used as a natural binding agent in the composition. Then the fibers were mixed and blended with black liquor without any resin addition. The amount of black liquor used per composite board was 20%, with approximately 37% solid content. The composites were fabricated using a hot press machine at two different board densities, 850 and 950 kg/m³, with two sets of hot pressing time, 25 and 35 minutes. Samples of the composites from different densities and hot pressing times were tested in flexural strength and internal bonding (IB) for strength performance according to British Standard. Modulus of elasticity (MOE) and modulus of rupture (MOR) was determined in flexural test, while tensile force perpendicular to the surface was recorded in IB test. Results show that the strength performance of the composites with 850 kg/m³ density were significantly higher than 950 kg/m³ density, especially for samples from 25 minutes hot pressing time. Strength performance of composites from 25 minutes hot pressing time were generally greater than 35 minutes. Results show that the maximum mean values of strength performance were recorded from composites with 850 kg/m³ density and 25 minutes pressing time. The maximum mean values for MOE, MOR and IB were 3251.84, 16.88 and 0.27 MPa, respectively. Only MOE result has conformed to high density fiberboard (HDF) standard (2700 MPa) in British Standard for Fiberboard Specification, BS EN 622-5: 2006. Microstructure characteristics of composites can also be related to the strength performance of the composites, in which, the observed fiber damage in composites from 950 kg/m³ density and overheat of black liquor led to the low strength properties, especially in IB test.

Keywords: bamboo fiber, natural bonded, black liquor, mechanical tests, microstructure observations

Procedia PDF Downloads 254

Authors: Sujith Gunawardhana

Abstract:

The circular economy is a system in which resources and energy are derived from renewable sources, utilized efficiently, recycled, and reused to reduce waste, reduce nonrenewable resource consumption, and mitigate negative environmental impacts. However, it poses moral questions about sustainability, the environment, and societal issues. Many societies face challenges when implementing the circular economy, as the concept is still young. The equitable distribution of the advantages and costs of circularity should be ensured during implementation, as some communities, particularly disadvantaged or marginalized ones, may suffer unfairly disproportionately from the harmful effects of production and recycling facilities. Prioritizing the health and safety of workers, communities, and the environment is essential, and strict rules must be implemented to guard against harm. However, most underdeveloped countries need a legal safeguard for this situation. The ultimate objective of the circular economy is to improve social, environmental, and economic performance, but its implementation also requires consideration of the ethics of care and non-epistemic values. Those are often hindered in underdeveloped countries, as the availability of infrastructure and technology, affordability, and legislative framework are poor. To achieve long-term success in the circular economy, evaluating implementation steps and considering health, safety, environmental, and social risks is crucial. To implement the circular economy, respect ethics of care and non-epistemic values. Adopt Kantian Ethics and control technology design to ensure equal benefits for all involved. Ethical gaps may lead underdeveloped countries to generate social pressure against the circular economy.

Keywords: circular economy, ethics, values, sustainability

Procedia PDF Downloads 109