Search results for: positive temperature coefficient
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 14860

Search results for: positive temperature coefficient

5950 Noticing Nature: Benefits for Connectedness to Nature and Wellbeing

Authors: Dawn Watling, Lorraine Lecourtois, Adnan Levent, Ryan Jeffries, Aysha Bellamy

Abstract:

Mental health diagnoses are on the rise for adolescents worldwide, with many being unable to access support and increasing use of social prescribing time in nature. There is an increasing need to better understand the preventive benefits of spending time in nature. In this paper, research findings from 599 seven to 12-year-olds completed two sets of questionnaires (before the visit and after a walk in nature). Participants spent time in one of three different biodiverse habitats. Findings explore predictors (including age, sex, and mental health) of increases in connection to nature and well-being. Secondly, research findings from 313 eighteen to 87-year-olds who completed questionnaires and had their heart rate monitored, followed by a self-guided walk, will be discussed. Findings explore predictors (including age, sex, connectedness to nature, well-being, and heart rate as a proxy measure of stress) of increases in mood and feelings of restoration. The discussion will focus on the converging evidence for taking time to notice nature and the role of different environments in enhancing connection to nature, well-being, and positive mental health.

Keywords: nature, connectedness to nature, social prescribing, wellbeing

Procedia PDF Downloads 12
5949 Numerical Investigation into the Effect of Axial Fan Blade Angle on the Fan Performance

Authors: Shayan Arefi, Qadir Esmaili, Seyed Ali Jazayeri

Abstract:

The performance of cooling system affects on efficiency of turbo generators and temperature of winding. Fan blade is one of the most important components of cooling system which plays a significant role in ventilation of generators. Fan performance curve depends on the blade geometry and boundary condition. This paper calculates numerically the performance curve of axial flow fan mounted on turbo generator with 160 MW output power. The numerical calculation was implemented by Ansys-workbench software. The geometrical model of blade was created by bladegen, grid generation and configuration was made by turbogrid and finally, the simulation was implemented by CFX. For the first step, the performance curves consist of pressure rise and efficiency flow rate were calculated in the original angle of blade. Then, by changing the attack angle of blade, the related performance curves were calculated. CFD results for performance curve of each angle show a good agreement with experimental results. Additionally, the field velocity and pressure gradient of flow near the blade were investigated and simulated numerically with varying of angle.

Keywords: turbo generator, axial fan, Ansys, performance

Procedia PDF Downloads 355
5948 Influence Analysis of Profit Sharing Agreement and Financing Risk to Profitability in Islamic Bank of Indonesia

Authors: Irena Paramita Pramono

Abstract:

Islamic bank is a financial industry with huge potential to grow in Indonesia. Profit-sharing agreement in the operations of Islamic banks distinguishes Islamic banks with conventional banks. Profit-sharing agreement allows sharing of benefits and risks between shahibul maal and mudharib in islamic bank. This study aimed to observe the patterns of influence between the risk-sharing agreement, financing risk and Profitability in Islamic banks. This research used several Islamic banks as sample and path analysis method. The empirical results of this research shows that the profit-sharing agreement in deposits structure has no direct significant effect to ROA, but it has indirect effect to ROA through profit-sharing financing. On the other hand, profit-sharing financing has direct and indirect influence to ROA through financing risk. This research shows that profit-sharing financing has a positive significant effect to the financing risk and also to the ROA. The research recommends Islamic banks to continue using and developing profit-sharing agreement in its operational activities, hence to create value.

Keywords: Islamic bank, profit-loss sharing agreement, financing risk, profitability

Procedia PDF Downloads 786
5947 Investigating Changes in Hip and Knee Joints Position in Girls with Patellofemoral Syndrome

Authors: Taraneh Ashrafi Motlagh, Abdolrasoul Daneshjoo

Abstract:

Background and Aim: Increased fatigue causes injuries; the purpose of this article was to investigate the angular displacement of the hip and knee joints in girls with patellofemoral syndrome. Materials and Methods: Thirty girls with an average age (age 28.73±1.83, height 168.49±5.59, weight 63.73±12.73) participated in this study in two groups of 15, experimental and control. The jet evaluation test was taken from the subjects' knee and thigh angle, and then these tests were repeated with the application of different inclines of the treadmill; the tests were examined in a neutral position and in a positive and negative slope of 5 degrees. The mean and standard deviation were used to describe the data, and the Shapirovik test was used for the normalization of the data to compare and examine the variables in the two research groups using an independent t-test and repeated analysis of variance at a significance level of 0.05. Conclusion: In general, according to the current studies of people with patellofemoral syndrome, running on steep inclines, as well as running on a treadmill and making the incline angle of the treadmill within the limit of minus 5% to plus 5%, does not affect the improvement of this condition, and it is not recommended. And according to the research, girls with patellofemoral syndrome should be placed on the treadmill at an inclined angle to run.

Keywords: patellofemoral syndrome, angular displacement of the knee, angular displacement of the thigh

Procedia PDF Downloads 45
5946 Raising Multilingual Awareness towards Plurilingual Competence Development: Through Which Approach and Which Pedagogical Material-A Case Study in the Greek Primary Education

Authors: Eftychia Damaskou

Abstract:

This article intends to place the question of the adequate approach for teaching multilingualism within the public education. Linguistic education, as it is defined by the Common European Framework of Reference for the Languages, is no longer the proficiency in one or two languages. It’s about the development of a linguistic repertoire, where all linguistic skills find their place. In fact, the linguistic theories that frame the development of plurilingual competence point out the affective and intercultural aspect of such a process, insisting on an awareness of linguistic diversification, rather than an acquisition of communicative competence in many languages. In this spirit, our article attempts to go beyond a mere plurilingual awareness, present a research based on an experience in class, within 115 pupils, aiming at the development of plurilingual competence in five unknown foreign languages. This experience was held through a teaching unit personally conceived and applied, and consisted of a series of 6 activities based on a cross-linguistic content approach. The data analysis proves to be very interesting, as it reveals the development of plurilingual competences, as well as positive attitudes towards less common languages by the majority of our sample.

Keywords: multilingual awareness, multilingual teaching material, plurilingual competence

Procedia PDF Downloads 437
5945 Bio-Furan Based Poly (β-Thioether Ester) Synthesized via Thiol-Michael Addition Polymerization with Tunable Structure and Properties

Authors: Daihui Zhang, Marie J. Dumont

Abstract:

A derivative of 5-hydroxymethylfurfural (HMF) was synthesized for the thiol-Michael addition reaction. The efficiency of the catalysts (base and nucleophiles) and side reactions during the thiol-Michael addition were investigated. Dimethylphenylphosphine efficiently initiated the thiol-Michael addition polymerization for synthesizing a series of bio-based furan polymers with different structure and properties. The benzene rings or hydroxyl groups present in the polymer chains increased the glass transition temperature (Tg) of poly (β-thioether ester). Additionally, copolymers with various compositions were obtained via adding different ratio of 1,6-hexanedithiols to 1,4-benzenedithiols. 1H NMR analysis revealed that experimental ratios of two dithiols monomers matched well with theoretical ratios. The occurrence of a reversible Diels-Alder reaction between furan rings and maleimide groups allowed poly (β-thioether ester) to be dynamically crosslinked. These polymers offer the potentials to produce materials from biomass that have both practical mechanical properties and reprocessing ability.

Keywords: copolymers, Diels-Alder reaction, hydroxymethylfurfural, Thiol-Michael addition

Procedia PDF Downloads 316
5944 A Comparative Study on the Effectiveness of Conventional Physiotherapy Program, Mobilization and Taping with Proprioceptive Training for Patellofemoral Pain Syndrome

Authors: Mahesh Mitra

Abstract:

Introduction and Purpose: Patellofemoral Pain Syndrome [PFPS] is characterized by pain or discomfort seemingly originating from the contact of posterior surface of Patella with Femur. Given the multifactorial causes and high prevalence there is a need of proper management technique. Also a more comprehensive and best possible Physiotherapy treatment approach has to be devised to enhance the performance of the individual with PFPS. Purpose of the study was to: - Prevalence of PFPS in various sports - To determine if there exists any relationship between the Body Mass Index[BMI] and Pain Intensity in the person playing a sport. - To evaluate the effect of conventional Physiotherapy program, Mobilization and Taping with Proprioceptive training on PFPS. Hypothesis 1. Prevalence is not the same with different sporting activities 2. There is a relationship between BMI and Pain intensity. 3. There is no significant difference in the improvement with the different treatment approaches. Methodology: A sample of 200 sports men were tested for the prevalence of PFPS and their anthropometric measurements were obtained to check for the correlation between BMI vs Pain intensity. Out of which 80 diagnosed cases of PFPS were allotted into three treatment groups and evaluated for Pain at rest and at activity and KUJALA scale. Group I were treated with conventional Physiotherapy that included TENS application and Exercises, Group II were treated with compression mobilization along with exercises, Group III were treated with Taping and Proprioceptive exercises. The variables Pain on rest, activity and KUJALA score were measured initially, at 1 week and at the end of 2 weeks after respective treatment. Data Analysis - Prevalence percentage of PFPS in each sport - Pearsons Correlation coefficient to find the relationship between BMI and Pain during activity. - Repeated measures analysis of variance [ANOVA] to find out the significance during Pre, Mid and Post-test difference among - Newman Kuel Post hoc Test - ANCOVA for the difference amongst group I, II and III. Results and conclusion It was concluded that PFPS was more prevalent in volley ball players [80%] followed by football and basketball [66%] players, then in hand ball and cricket players [46.6%] and 40% in tennis players. There was no relationship between BMI of the individual and Pain intensity. All the three treatment approaches were effective whereas mobilization and taping were more effective than Conventional Physiotherapy program.

Keywords: PFPS, KUJALA score, mobilization, proprioceptive training

Procedia PDF Downloads 303
5943 Protection of Human Rights in Europe: The Parliamentary Dimension

Authors: Aleksandra Chiniaeva

Abstract:

The following paper describes the activity of national and international parliamentary assemblies of the European region in protection and promotion of human rights. It may be said that parliamentarians have a “double mandate” — as members of the international assembly and of their respective national parliaments. In other words, parliamentarization at both international and national level provides a situation for parliamentarians, where they link people, national governments and international organizations. The paper is aimed towards demonstrating that the activity of the main international parliamentary assemblies of the European region have a real positive impact on the human rights situation in the European region. In addition, the paper describes the assemblies that include protection of human rights in their Agenda as one of the main subjects: the EP, the PACE, the OSCE PA and the IPA CIS. Co-operation activities such as joint election observation; participation in inter-parliamentary associations, such as the IPU; conclusion agreements allow assemblies to provide observation of human right situation in the states that are not members of the particular organization and as consequence make their impact broader.

Keywords: human rights, international parliamentary assembly, IPU, EP, PACE, OSCE, international election observation

Procedia PDF Downloads 350
5942 Hydrogen Storage in Salt Caverns: Rock Mechanical Design

Authors: Dirk Zapf, Bastian Leuger

Abstract:

For several years, natural gas and crude oil have been stored in salt caverns in Germany and also worldwide. The dimensioning concepts have been continuously developed from a rock mechanics point of view. In addition to the possibilities of realizing large numerical calculation models based on real survey data nowadays, especially the consideration of mechanical processes such as damage and healing played a role in the development of adequate material laws. In addition, thermodynamic aspects have had to be considered for some years in the operation of a gas storage cavern since temperature changes have a significant influence on the stress states in the vicinity of a storage cavern. The possibility of thermally induced fracturing processes is also investigated in the context of rock mechanics dimensioning. In recent years, the energy crisis and the finite nature of fossil fuel use have led to increased discussion of the use of salt caverns for hydrogen storage. In this paper, state of the art is presented, the current research work is described, and an outlook is given as to which questions still need to be answered from a rock mechanics point of view in connection with large-scale storage of hydrogen in salt caverns.

Keywords: cavern design, hydrogen, rock salt, thermomechanical coupled calculations

Procedia PDF Downloads 95
5941 Stochastic Frontier Application for Evaluating Cost Inefficiencies in Organic Saffron

Authors: Pawan Kumar Sharma, Sudhakar Dwivedi, R. K. Arora

Abstract:

Saffron is one of the most precious spices grown on the earth and is cultivated in a very limited area in few countries of the world. It has also been grown as a niche crop in Kishtwar district of Jammu region of Jammu and Kashmir State of India. This paper attempts to examine the presence of cost inefficiencies in saffron production and the associated socio-economic characteristics of saffron growers in the mentioned area. Although the numbers of inputs used in cultivation of saffron were limited, still cost inefficiencies were present in its production. The net present value (NPV), internal rate of return (IRR) and profitability index (PI) of investment in five years of saffron production were INR 1120803, 95.67 % and 3.52 respectively. The estimated coefficients of saffron stochastic cost function for saffron bulbs, human labour, animal labour, manure and saffron output were positive. The saffron growers having non-farm income were more cost inefficient as compared to farmers who did not have sources of income other than farming by 0.04 %. The maximum value of cost efficiency for saffron grower was 1.69 with mean value of 1.12. The majority of farmers have low cost inefficiencies, as the highest frequency of occurrence of the predicted cost efficiency was below 1.06.

Keywords: saffron, internal rate of return, cost efficiency, stochastic frontier model

Procedia PDF Downloads 137
5940 Antibacterial and Antioxidant Activities of Artemisia herba-alba Asso Essential Oil Growing in M’sila (Algeria)

Authors: Asma Meliani, S. Lakehal, F. Z. Benrebiha, C. Chaouia

Abstract:

There is an increasing interest in phytochemicals as new source of natural antioxidant and antimicrobial agents. Plants essential oils have come more into the focus of phytomedicine. Many researchers have reported various biological and/or pharmacological properties of Artemisia herba alba Asso essential oil. The present study describes antimicrobial and antioxidant properties of Artemisia herba alba Asso essential oil. Artemisia herba alba Asso essential oil obtained by hydrodistillation (using Clevenger type apparatus) growing in Algeria (M’sila) was analyzed by GC-MS. The essential oil yield of the study was 0.7%. The major components were found to be camphor, chrysanthenone et 1,8-cineole. The antimicrobial activity of the essential oil was tested against four bacteria (Gram-negative and Gram-positive) and three fungi using the diffusion method and by determining the inhibition zone. The oil was found to have significant antibacterial activity. In addition, antioxidant activity was determined by 1, 1-diphenyl-1-picrylhydrazyl (DPPH) assay, ferric reducing (FRAP) assay and β-carotene bleaching test, and high activity was found for Artemisia herba-alba oil.

Keywords: Artemisia herba-alba, essential oil, antibacterial activity, antioxidant activity

Procedia PDF Downloads 317
5939 Development of a Robust Procedure for Generating Structural Models of Calcium Aluminosilicate Glass Surfaces

Authors: S. Perera, T. R. Walsh, M. Solvang

Abstract:

The structure-property relationships of calcium aluminosilicate (CAS) glass surfaces are of scientific and technological interest regarding dissolution phenomena. Molecular dynamics (MD) simulations can provide atomic-scale insights into the structure and properties of the CAS interfaces in vacuo as the first step to conducting computational dissolution studies on CAS surfaces. However, one limitation to date is that although the bulk properties of CAS glasses have been well studied by MD simulation, corresponding efforts on CAS surface properties are relatively few in number (both theoretical and experimental). Here, a systematic computational protocol to create CAS surfaces in vacuo is developed by evaluating the sensitivity of the resultant surface structure with respect to different factors. Factors such as the relative thickness of the surface layer, the relative thickness of the bulk region, the cooling rate, and the annealing schedule (time and temperature) are explored. Structural features such as ring size distribution, defect concentrations (five-coordinated aluminium (AlV), non-bridging oxygen (NBO), and tri-cluster oxygen (TBO)), and linkage distribution are identified as significant features in dissolution studies.

Keywords: MD simulation, CAS glasses, surface structure, structure-property, CAS interface

Procedia PDF Downloads 83
5938 Manufacturing an Eminent Mucolytic Medicine Using an Efficient Synthesis Path

Authors: Farzaneh Ziaee, Mohammad Ziaee

Abstract:

N-acetyl-L-cysteine (NAC) is a well-known mucolytic agent, and recently its efficacy has been examined for the prevention and remediation of several diseases such as lung infections caused by Coronavirus. Also, it is administrated as the main antidote in paracetamol overdose and is effective for the treatment of idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD). This medicine is used as an antioxidant to prevent diabetic kidney disease (nephropathy). In this study, a method for the acylation of amino acids is employed to manufacture this drug in a height yield. Regarding this patented path, NAC can be made in a single batch step at ambient pressure and temperature. Moreover, this study offers a technique to make peptide bonds which is of interest for pharmaceutical and medicinal industries. The separation process was undertaken using appropriate solvents to achieve an excellent purification level. The synthesized drug was characterized via proton nuclear magnetic resonance (1H NMR), high-performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FT-IR), elemental analysis, and melting point.

Keywords: N-acetylcysteine, synthesis, mucolytic medication, lung anti-inflammatory, COVID-19, antioxidant, pharmaceutical supplement, characterization

Procedia PDF Downloads 179
5937 Mathematical Study of CO₂ Dispersion in Carbonated Water Injection Enhanced Oil Recovery Using Non-Equilibrium 2D Simulator

Authors: Ahmed Abdulrahman, Jalal Foroozesh

Abstract:

CO₂ based enhanced oil recovery (EOR) techniques have gained massive attention from major oil firms since they resolve the industry's two main concerns of CO₂ contribution to the greenhouse effect and the declined oil production. Carbonated water injection (CWI) is a promising EOR technique that promotes safe and economic CO₂ storage; moreover, it mitigates the pitfalls of CO₂ injection, which include low sweep efficiency, early CO₂ breakthrough, and the risk of CO₂ leakage in fractured formations. One of the main challenges that hinder the wide adoption of this EOR technique is the complexity of accurate modeling of the kinetics of CO₂ mass transfer. The mechanisms of CO₂ mass transfer during CWI include the slow and gradual cross-phase CO₂ diffusion from carbonated water (CW) to the oil phase and the CO₂ dispersion (within phase diffusion and mechanical mixing), which affects the oil physical properties and the spatial spreading of CO₂ inside the reservoir. A 2D non-equilibrium compositional simulator has been developed using a fully implicit finite difference approximation. The material balance term (k) was added to the governing equation to account for the slow cross-phase diffusion of CO₂ from CW to the oil within the gird cell. Also, longitudinal and transverse dispersion coefficients have been added to account for CO₂ spatial distribution inside the oil phase. The CO₂-oil diffusion coefficient was calculated using the Sigmund correlation, while a scale-dependent dispersivity was used to calculate CO₂ mechanical mixing. It was found that the CO₂-oil diffusion mechanism has a minor impact on oil recovery, but it tends to increase the amount of CO₂ stored inside the formation and slightly alters the residual oil properties. On the other hand, the mechanical mixing mechanism has a huge impact on CO₂ spatial spreading (accurate prediction of CO₂ production) and the noticeable change in oil physical properties tends to increase the recovery factor. A sensitivity analysis has been done to investigate the effect of formation heterogeneity (porosity, permeability) and injection rate, it was found that the formation heterogeneity tends to increase CO₂ dispersion coefficients, and a low injection rate should be implemented during CWI.

Keywords: CO₂ mass transfer, carbonated water injection, CO₂ dispersion, CO₂ diffusion, cross phase CO₂ diffusion, within phase CO2 diffusion, CO₂ mechanical mixing, non-equilibrium simulation

Procedia PDF Downloads 155
5936 Recovery of Essential Oil from Zingiber Officinale Var. Bentong Using Ultrasound Assisted-Supercritical Carbon Dioxide Extraction

Authors: Norhidayah Suleiman, Afza Zulfaka

Abstract:

Zingiber officinale var. Bentong has been identified as the source of high added value compound specifically gingerol-related compounds. The extraction of the high-value compound using conventional method resulted in low yield and time consumption. Hence, the motivation for this work is to investigate the effect of the extraction technique on the essential oil from Zingiber officinale var. Bentong rhizome for commercialization purpose in many industries namely, functional food, pharmaceutical, and cosmeceutical. The investigation begins with a pre-treatment using ultrasound assisted in order to enhance the recovery of essential oil. It was conducted at a fixed frequency (20 kHz) of ultrasound with various time (10, 20, 40 min). The extraction using supercritical carbon dioxide (scCO2) were carried out afterward at a specific condition of temperature (50 °C) and pressure (30 MPa). scCO2 extraction seems to be a promising sustainable green method for the extraction of essential oil due to the benefits that CO2 possesses. The expected results demonstrated the ultrasound-assisted-scCO2 produces a higher yield of essential oil compared to solely scCO2 extraction. This research will provide important features for its application in food supplements or phytochemical preparations.

Keywords: essential oil, scCO2, ultrasound assisted, Zingiber officinale Var. Bentong

Procedia PDF Downloads 121
5935 Optimizing Cellulase Production from Municipal Solid Wastes (MSW) Following a Solid State Fermentation (SSF) by Trichoderma reesei and Aspergillus niger

Authors: Jwan J. Abdullah, Greetham Darren, Gregory A, Tucker, Chenyu Du

Abstract:

Solid-state fermentation (SSF) is an alternative to liquid fermentations for the production of commercially important products such as antibiotics, single cell proteins, enzymes, organic acids, or biofuels from lignocellulosic material. This paper describes the optimisation of SSF on municipal solid waste (MSW) for the production of cellulase enzyme. Production of cellulase enzymes was optimised by Trichoderma reesei or Aspergillus niger for temperature, moisture content, inoculation, and period of incubation. Also, presence of minerals, and alternative carbon and nitrogen sources. Optimisation revealed that production of cellulolytic enzymes was optimal when using Trichoderma spp at 30°C with an incubation period of 168 hours with a 60% moisture content. Crude enzymes produced from MSW, by Trichoderma were evaluated for the saccharification of MSW and compared with activity of a commercially available enzyme, results demonstrated that MSW can be used as inexpensive lignocellulosic material for the production of cellulase enzymes using Trichoderma reesei.

Keywords: SSF, enzyme hydrolysis, municipal solid waste (MSW), optimizing conditions, enzyme hydrolysis

Procedia PDF Downloads 539
5934 Dietary Ergosan as a Supplemental Nutrient on Growth Performance, and Stress in Zebrafish (Danio Rerio)

Authors: Ehsan Ahmadifar, Mohammad Ali Yousefi, Zahra Roohi

Abstract:

In this study, the effects of different levels of Ergosan (control group (0), 2, 4 and 6 gr Ergosan per Kg diet) as a nutritional supplement were investigated on growth indices and stress in Zebrafish for 3 months. Larvae (4-day-old after hatching) were fed with experimental diet from the beginning of feeding until adult (adolescence) (average weight: 69.3 g, length: 5.1 cm). Different levels of Ergosan had no significant effect on rate survival (P < 0.05). The results showed that diet containing 6 gr Ergosan significantly caused the best FCR in Zebrafish (P < 0.05). By increasing the Ergosan diet, specific growth rate increased. Body weight gain and condition factor had significant differences (P < 0.05) as the highest and the lowest were observed in treatment 3 gr of Ergosan and control, respectively. The results showed that fish fed with experimental diet, had the highest resistance to environmental stresses compared to control, and the test temperature, oxygen, salinity and alkalinity samples containing 6 gr/kg, was significantly more resistance compared to the other treatments (P < 0.05). Overall, to achieve high resistance to environmental stress and increase final biomass using 6 gr/kg Ergosan in diet fish Zebrafish.

Keywords: Ergosan, stress, growth performance, Danio rerio

Procedia PDF Downloads 235
5933 The English Classroom: Scope and Space for Motivation

Authors: Madhavi Godavarthy

Abstract:

The globalized world has been witnessing the ubiquity of the English language and has made it mandatory that students be equipped with the required Communication and soft skills. For students and especially for students studying in technical streams, gaining command over the English language is only a part of the bigger challenges they will face in the future. Linguistic capabilities if blended with the right attitude and a positive personality would deliver better results in the present environment of the digitalized world. An English classroom has that ‘space’; a space if utilized well by the teacher can pay rich dividends. The prescribed syllabus for English in the process of adapting itself to the challenges of a more and more technical world has meted out an indifferent treatment in including ‘literary’ material in their curriculum. A debate has always existed regarding the same and diversified opinions have been given. When the student is motivated to reach Literature through intrinsic motivation, it may contribute to his/her personality-development. In the present paper, the element of focus is on the scope and space to motivate students by creating a specific space for herself/himself amidst the schedules of the teaching-learning processes by taking into consideration a few literary excerpts for the purpose.

Keywords: English language, teaching and learning process, reader response theory, intrinsic motivation, literary texts

Procedia PDF Downloads 599
5932 Comparison of Two Artificial Accelerated Weathering Methods of Larch Wood with Natural Weathering in Exterior Conditions

Authors: I. Sterbova, E. Oberhofnerova, M. Panek, M. Pavelek

Abstract:

With growing popularity, wood of European larch (Larix decidua, Mill.) is being more often applied into the exterior, usually as facade elements, also without surface treatment. The aim of this work was to compare two laboratory tests of artificial accelerated weathering of wood with two ways of natural weathering in the exterior. To assess changes in selected surface characteristics of larch wood, accelerated weathering methods in the Xenotest and UV chamber were used, both in combination with temperature cycling, for 6 weeks. They were compared with natural weathering results at exposition under 45° and 90° in the exterior for 12 months. The changes of colour, gloss, contact angle of water and also changes in visual characteristics were evaluated. The results of wood surfaces changes after 6 weeks of accelerated weathering in Xenotest are closer to 12 months of natural weathering in the exterior at an angle of 90° compared to the UV chamber testing. The results, especially the colour changes, of the samples exposed at an angle of 45° in the exterior were significantly different. Testing in Xenotest more closely simulates the weathering of façade elements in the exterior compared to the UV chamber testing.

Keywords: larch wood, wooden facade, wood accelerated weathering, weathering methods

Procedia PDF Downloads 131
5931 Influence of Silica Fume on the Hydration of Cement Pastes Studied by Simultaneous TG-DSC Analysis

Authors: Anton Trník, Lenka Scheinherrová, Robert Černý

Abstract:

Silica fume is a by-product of the ferro-silicon and silicon metal industries. It is mainly in the form of amorphous silica. Silica fume belongs to pozzolanic active materials which can be used in concrete to improve its final properties. In this paper, the influence of silica fume on hydration of cement pastes is studied using differential scanning calorimetry (DSC) and thermogravimetry (TG) at various curing times (2, 7, 28, and 90 days) in the temperature range from 25 to 1000 °C in an argon atmosphere. Samples are prepared from Portland cement CEM I 42.5 R which is partially replaced with the silica fume of 4, 8, and 12 wt.%. The water/binder ratio is chosen as 0.5. It is identified and described the liberation of physically bound water, calcium–silicate–hydrates dehydration, portlandite and calcite decomposition in studied samples. Also, it is found out that an exothermic peak at 950 °C is observed without a significant mass change for samples with 12 wt.% of silica fume after two days of hydration. This peak is probably caused by the pozzolanic reaction between silica fume and Portland cement. Its size corresponds to the degree of crystallization between Ca and Si. The portlandite content is lower for the samples with a higher amount of silica fume.

Keywords: differential scanning calorimetry, hydration, silica fume, thermogravimetry

Procedia PDF Downloads 228
5930 Local Government Digital Attention and Green Technology Innovation: Analysis Based on Spatial Durbin Model

Authors: Xin Wang, Chaoqun Ma, Zheng Yao

Abstract:

Although green technology innovation faces new opportunities and challenges in the digital era, its theoretical research remains limited. Drawing on the attention-based view, this study employs the spatial Durbin model to investigate the impact of local government digital attention and digital industrial agglomeration on green technology innovation across 30 Chinese provinces from 2011 to 2021, as well as the spatial spillover effects present. The results suggest that both government digital attention and digital industrial agglomeration positively influence green technology innovation in local and neighboring provinces, with digital industrial agglomeration exhibiting a positive moderating effect on this direct local and indirect spatial spillover relationship. The findings of this study provide a new theoretical perspective for green technology innovation research and hold valuable implications for the advancement of the attention-based view and green technology innovation.

Keywords: local government digital attention, digital industrial agglomeration, green technology innovation, attention-based view

Procedia PDF Downloads 54
5929 Conceptual Analysis of the Implications of Black Fathers’ Lifestyles and Their Involvement in their Children’s Early Development

Authors: Chinedu Ifedi Okeke

Abstract:

The behavioural orientations of fathers, which resonate in the way they relate to members of their families and other community members, appear to have a variety of implications for the early development of children. In this paper, a conceptual map of fathers’ lifestyles is adopted to provide an interconnected network of father lifestyles. Empirical evidence from a qualitative case study of 25 Black fathers, who had been purposively selected from a suburb in one rural Eastern Cape municipality in South Africa, is reported in this paper. Semi-structured in-depth interviews were used to obtain data, which was analysed thematically. Findings identify and provide evidence of father lifestyles that are incongruent with the kind of parental behaviour needed to support the healthy early development of children. Findings suggest that these negative lifestyles appear to incapacitate fathers who fail to make a positive contribution to their children’s early development. To ensure that fathers make the expected contributions to their children’s early development, policies aimed at rehabilitating fathers who are involved in the negative lifestyles reported in this paper should be put in place.

Keywords: childhood development, fathering, fathers, intervention strategies, lifestyles, South Africa

Procedia PDF Downloads 117
5928 The Impact of Student-Led Entrepreneurship Education through Skill Acquisition in Federal Polytechnic, Bida, Niger State, Nigeria

Authors: Ibrahim Abubakar Mikugi

Abstract:

Nigerian graduates could only be self-employed and marketable if they acquire relevant skills and knowledge for successful establishment in various occupation and gainful employment. Research has shown that entrepreneurship education will be successful through developing individual entrepreneurial attitudes, raising awareness of career options by integrating and inculcating a positive attitude in the mind of students through skill acquisition. This paper examined the student- led entrepreneurship education through skill acquisition with specific emphasis on analysis of David Kolb experiential learning cycle. This Model allows individual to review their experience through reflection and converting ideas into action by doing. The methodology used was theoretical approach through journal, internet and Textbooks. Challenges to entrepreneurship education through skill acquisition were outlined. The paper concludes that entrepreneurship education is recognised by both policy makers and academics; entrepreneurship is more than mere encouraging business start-ups. Recommendations were given which include the need for authorities to have a clear vision towards entrepreneurship education and skill acquisition. Authorities should also emphasise a periodic and appropriate evaluation of entrepreneurship and to also integrate into schools academic curriculum to encourage practical learning by doing.

Keywords: entrepreneurship, entrepreneurship education, active learning, Cefe methodology

Procedia PDF Downloads 500
5927 Small and Medium-Sized Enterprises in West African Semi-Arid Lands Facing Climate Change

Authors: Mamadou Diop, Florence Crick, Momadou Sow, Kate Elizabeth Gannon

Abstract:

Understanding SME leaders’ responses to climate is essential to cope with ongoing changes in temperature and rainfall. This study analyzes the response of SME leaders to the adverse effects of climate change in semi-arid lands (SAL) in Senegal. Based on surveys administrated to 161 SME leaders, this research shows that 91% of economic units are affected by climatic conditions, although 70% do not have a plan to deal with climate risks. Economic actors have striven to take measures to adapt. However, their efforts are limited by various obstacles accentuated by a lack of support from public authorities. In doing so, substantial political, institutional and financial efforts at national and local levels are needed to promote an enabling environment for economic actors to adapt. This will focus on information and training about the threats and opportunities related to global warming, the creation of an adaptation support fund to support local initiatives and the improvement of the institutional, regulatory and political framework.

Keywords: small and medium-sized enterprises, climate change, adaptation, semi-arid lands

Procedia PDF Downloads 192
5926 A Rare Case of Atypical Guillian-Barre Syndrome Following Antecedent Dengue Infection

Authors: Amlan Datta

Abstract:

Dengue is an arboviral, vector borne infection, quite prevalent in tropical countries such as India. Approximately, 1 to 25% of cases may give rise to neurological complication, such as, seizure, delirium, Guillian-Barre syndrome (GBS), multiple cranial nerve palsies, intracranial thrombosis, stroke-like presentations, to name a few. Dengue fever, as an antecedent to GBS is uncommon, especially in adults.Here, we report a case about a middle aged lady who presented with an acute onset areflexic ascending type of polyradiculoneuropathy along with bilateral lower motor neuron type of facial nerve palsy, as well as abducens and motor component of trigeminal (V3) weakness. Her respiratory and neck muscles were spared. She had an established episode of dengue fever (NS1 and dengue IgM positive) 7 days prior to the weakness. Nerve conduction study revealed a demyelinating polyradiculopathy of both lower limbs and cerebrospinal fluid examination showed albuminocytological dissociation. She was treated with 5 days of intravenous immunoglobulin (IVIg), following which her limb weakness improved considerably. This case highlights GBS as a potential complication following dengue fever.

Keywords: areflexic, demyelinating, dengue, polyradiculoneuropathy

Procedia PDF Downloads 239
5925 Flexural Behavior of Heat-Damaged Concrete Beams Reinforced with Fiber Reinforced Polymer (FRP) Bars

Authors: Mohammad R. Irshidat, Rami H. Haddad, Hanadi Al-Mahmoud

Abstract:

Reinforced concrete (RC) is the most common used material for construction in the world. In the past decades, fiber reinforced polymer (FRP) bars had been widely used to substitute the steel bars due to their high resistance to corrosion, high tensile capacity, and low weight in comparison with steel. Experimental studies on the behavior of FRP bar reinforced concrete beams had been carried out worldwide for a few decades. While the research on such structural members under elevated temperatures is still very limited. In this research, the flexural behavior of heat-damaged concrete beams reinforced with FRP bars is studied. Two types of FRP rebar namely, carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP), are used. The beams are subjected to four levels of temperature before tested to monitor their flexural behavior. The results are compared with other concrete beams reinforced with regular steel bars. The results show that the beams reinforced with CFRP bars and GFRP bars had higher flexural capacity than the beams reinforced with steel bars even if heated up to 400°C and 300°C, respectively. After that the beams reinforced with steel bars had the superiority.

Keywords: concrete beams, FRP rebar, flexural behavior, heat-damaged

Procedia PDF Downloads 430
5924 Macroscopic Evidence of the Liquidlike Nature of Nanoscale Polydimethylsiloxane Brushes

Authors: Xiaoxiao Zhao

Abstract:

We report macroscopic evidence of the liquidlike nature of surface-tethered poly(dimethylsiloxane) (PDMS) brushes by studying their adhesion to ice. Whereas ice permanently detaches from solid surfaces when subjected to sufficient shear, commonly referred to as the material’s ice adhesion strength, adhered ice instead slides over PDMS brushes indefinitely. When additionally methylated, we observe a Couette-like flow of the PDMS brushes between the ice and silicon surface. PDMS brush ice adhesion displays shear-rate-dependent shear stress and rheological behavior reminiscent of liquids and is affected by ice velocity, temperature, and brush thickness, following scaling laws akin to liquid PDMS films. This liquidlike nature allows it to detach solely by self-weight, yielding an ice adhesion strength of 0.3 kPa, 1000 times less than low surface energy, perfluorinated monolayer. The methylated PDMS brushes also display omniphobicity, repelling all liquids essentially with vanishingly small contact angle hysteresis. Methylation results in significantly higher contact angles than previously reported, nonmethylated brushes, especially for polar liquids of both high and low surface tension.

Keywords: omniphobic, surface science, polymer brush, icephobic surface

Procedia PDF Downloads 52
5923 A New Correlation between SPT and CPT for Various Soils

Authors: Fauzi Jarushi, Sinan Mohsin AlKaabi

Abstract:

The Standard Penetration Test (SPT) is the most common insitu test for soil investigations. On the other hand, the Cone Penetration Test (CPT) is considered one of the best investigation tools. Due to the fast and accurate results that can be obtained it complaints the SPT in many applications like field explorations, design parameters, and quality control assessments. Many soil index and engineering properties have been correlated to both of SPT and CPT. Various foundation design methods were developed based on the outcome of these tests. Therefore it is vital to correlate these tests to each other so that either one of the tests can be used in the absence of the other, especially for preliminary evaluation and design purposes. The primary purpose of this study was to investigate the relationships between the SPT and CPT for different types of soil in Florida. Data for this research were collected from number of projects sponsored by the Florida Department of Transportation (FDOT), six sites served as the subject of SPT-CPT correlations. The correlations were established between the cone resistance (qc) and the SPT blows (i.e., N) for various soils. A positive linear relationship was found between fs and N for various soils. In general, qc versus N showed higher correlation coefficients than fs versus N. qc/N ratios were developed for different soil types and compared to literature values, the results of this research revealed higher ratios than literature values.

Keywords: in situ tests, correlation, SPT, CPT

Procedia PDF Downloads 386
5922 Antibacterial and Antioxidant Properties of Artemisia herba-alba Asso Essential Oil Growing in M’sila, Algeria

Authors: Asma Meliani, S. Lakehal, F. Z. Benrebiha, C. Chaouia

Abstract:

There is an increasing interest in phytochemicals as new source of natural antioxidant and antimicrobial agents. Plants essential oils have come more into the focus of phytomedicine. Many researchers have reported various biological and/or pharmacological properties of Artemisia herba alba Asso essential oil. The present study describes antimicrobial and antioxidant properties of Artemisia herba alba Asso essential oil. Artemisia herba alba Asso essential oil obtained by hydrodistillation (using Clevenger type apparatus) growing in Algeria (M’sila) was analyzed by GC-MS. The essential oil yield of the study was 0.7 %. The major components were found to be camphor, chrysanthenone et 1,8-cineole. The antimicrobial activity of the essential oil was tested against four bacteria (Gram-negative and Gram-positive) and one fungi using the diffusion method and by determining the inhibition zone. The oil was found to have significant antibacterial activity. In addition, antioxidant activity was determined by 1,1-diphenyl-1-picrylhydrazyl (DPPH) assay, ferric reducing (FRAP) assay and β-carotene bleaching test, and high activity was found for Artemisia herba-alba oil.

Keywords: Artemisia herba-alba, essential oil, antibacterial activity, antioxidant activity

Procedia PDF Downloads 452
5921 Day of the Week Patterns and the Financial Trends' Role: Evidence from the Greek Stock Market during the Euro Era

Authors: Nikolaos Konstantopoulos, Aristeidis Samitas, Vasileiou Evangelos

Abstract:

The purpose of this study is to examine if the financial trends influence not only the stock markets’ returns, but also their anomalies. We choose to study the day of the week effect (DOW) for the Greek stock market during the Euro period (2002-12), because during the specific period there are not significant structural changes and there are long term financial trends. Moreover, in order to avoid possible methodological counterarguments that usually arise in the literature, we apply several linear (OLS) and nonlinear (GARCH family) models to our sample until we reach to the conclusion that the TGARCH model fits better to our sample than any other. Our results suggest that in the Greek stock market there is a long term predisposition for positive/negative returns depending on the weekday. However, the statistical significance is influenced from the financial trend. This influence may be the reason why there are conflict findings in the literature through the time. Finally, we combine the DOW’s empirical findings from 1985-2012 and we may assume that in the Greek case there is a tendency for long lived turn of the week effect.

Keywords: day of the week effect, GARCH family models, Athens stock exchange, economic growth, crisis

Procedia PDF Downloads 396