Search results for: short fiber reinforced composite

Authors: M. Nerantzaki, I. Koliakou, D. Bikiaris

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This study evaluates the hypothesis that the incorporation of fibrous hydroxyapatite nanoparticles (nHA) with high crystallinity and high aspect ratio, synthesized by hydrothermal method, into Poly(butylene succinate) (PBSu), improves the bioactivity of the aliphatic polyester and affects new bone growth inhibiting resorption and enhancing bone formation. Hydroxyapatite nanorods were synthesized using a simple hydrothermal procedure. First, the HPO42- -containing solution was added drop-wise into the Ca2+-containing solution, while the molar ratio of Ca/P was adjusted at 1.67. The HA precursor was then treated hydrothermally at 200°C for 72 h. The resulting powder was characterized using XRD, FT-IR, TEM, and EDXA. Afterwards, PBSu nanocomposites containing 2.5wt% (nHA) were prepared by in situ polymerization technique for the first time and were examined as potential scaffolds for bone engineering applications. For comparison purposes composites containing either 2.5wt% micro-Bioglass (mBG) or 2.5wt% mBG-nHA were prepared and studied, too. The composite scaffolds were characterized using SEM, FTIR, and XRD. Mechanical testing (Instron 3344) and Contact Angle measurements were also carried out. Enzymatic degradation was studied in an aqueous solution containing a mixture of R. Oryzae and P. Cepacia lipases at 37°C and pH=7.2. In vitro biomineralization test was performed by immersing all samples in simulated body fluid (SBF) for 21 days. Biocompatibility was assessed using rat Adipose Stem Cells (rASCs), genetically modified by nucleofection with DNA encoding SB100x transposase and pT2-Venus-neo transposon expression plasmids in order to attain fluorescence images. Cell proliferation and viability of cells on the scaffolds were evaluated using fluoresce microscopy and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide) assay. Finally, osteogenic differentiation was assessed by staining rASCs with alizarine red using cetylpyridinium chloride (CPC) method. TEM image of the fibrous HAp nanoparticles, synthesized in the present study clearly showed the fibrous morphology of the synthesized powder. The addition of nHA decreased significantly the contact angle of the samples, indicating that the materials become more hydrophilic and hence they absorb more water and subsequently degrade more rapidly. In vitro biomineralization test confirmed that all samples were bioactive as mineral deposits were detected by X-ray diffractometry after incubation in SBF. Metabolic activity of rASCs on all PBSu composites was high and increased from day 1 of culture to day 14. On day 28 metabolic activity of rASCs cultured on samples enriched with bioceramics was significantly decreased due to possible differentiation of rASCs to osteoblasts. Staining rASCs with alizarin red after 28 days in culture confirmed our initial hypothesis as the presence of calcium was detected, suggesting osteogenic differentiation of rACS on PBSu/nHAp/mBG 2.5% and PBSu/mBG 2.5% composite scaffolds.

Keywords: biomaterials, hydroxyapatite nanorods, poly(butylene succinate), scaffolds

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Authors: Raymond Treacy, Paul Humphreys, Ronan McIvor, Trevor Cadden, Alan McKittrick

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This study employed event study methodology to examine the role of institutions, resources and dynamic capabilities in the relationship between the Environmental Management System ISO 14001 adoption and firm performance. Utilising financial data from 140 ISO 14001 certified firms and 320 non-certified firms, the results of the study suggested that the UK and Irish manufacturers were not implementing ISO 14001 solely to gain legitimacy. In contrast, the results demonstrated that firms were fully integrating the ISO 14001 standard within their operations as certified firms were able to improve both financial and operating performance when compared to non-certified firms. However, while there were significant and long lasting improvements for employee productivity, manufacturing cost efficiency, return on assets and sales turnover, the sample firms operating cycle and fixed asset efficiency displayed evidence of diminishing returns in the long-run, underlying the observation that no operating advantage based on incremental improvements can be everlasting. Hence, there is an argument for investing in dynamic capabilities which help renew and refresh the resource base and help the firm adapt to changing environments. Indeed, the results of the regression analysis suggest that dynamic capabilities for innovation acted as a moderator in the relationship between ISO 14001 certification and firm performance. This, in turn, will have a significant and symbiotic influence on sustainability practices within the participating organisations. The study not only provides new and original insights, but demonstrates pragmatically how firms can take advantage of environmental management systems as a moderator to significantly enhance firm performance. However, while it was shown that firm innovation aided both short term and long term ROA performance, adaptive market capabilities only aided firms in the short-term at the marketing strategy deployment stage. Finally, the results have important implications for firms operating in an economic recession as the results suggest that firms should scale back investment in R&D while operating in an economic downturn. Conversely, under normal trading conditions, consistent and long term investments in R&D was found to moderate the relationship between ISO 14001 certification and firm performance. Hence, the results of the study have important implications for academics and management alike.

Keywords: supply chain management, environmental management systems, quality management, sustainability, firm performance

Procedia PDF Downloads 313

Authors: Javier Menéndez, Jorge Loredo

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Large scale energy storage systems (LSESS) such as pumped-storage hydro-power (PSH) are required in the current energy transition towards a low carbon economy by using green energies that produce low levels of greenhouse gas (GHG) emissions. Coal mines are currently being closed in the European Union and their underground facilities may be used to build PSH plants. However, the development of this projects requires the excavation of a network of tunnels and a large cavern that would be used as a powerhouse to install the Francis turbine and motor-generator. The technical feasibility to excavate the powerhouse cavern has been analyzed in the North of Spain. Three-dimensional numerical models have been conducted to analyze the stability considering shale and sandstone rock mass. Total displacements and thickness of plastic zones were examined considering different support systems. Systematic grouted rock bolts and fibre reinforced shotcrete were applied at the cavern walls and roof. The results obtained show that the construction of the powerhouse is feasible applying proper support systems.

Keywords: closed mines, mine water, numerical model, pumped-storage, renewable energies

Procedia PDF Downloads 100

Authors: F. Boudet, V. Galano, D. Gmira, L. Munoz, A. Reina

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Commodities pricing needs a specific approach as they are often linked to each other and so are expectedly doing their prices. They are called co-integrated when at least one stationary linear combination exists between them. Though widespread in economic literature, and even if many equilibrium relations and co-movements exist in the economy, this principle of co-movement is not developed in derivatives field. The present study focuses on the following problem: How can the price of a forward agreement on a commodity be simulated, when it is co-integrated with other ones? Theoretical analysis is developed from Gibson-Schwartz model and an analytical solution is given for short maturities contracts and under risk-neutral conditions. The application has been made to crude oil and heating oil energy commodities and result confirms the applicability of proposed method.

Keywords: co-integration, commodities, forward pricing, Gibson-Schwartz

Procedia PDF Downloads 287

Authors: Antonis Skouloudis, Konstantinos Evangelinos, Walter Leal-Filho, Panagiotis Vouros, Ioannis Nikolaou

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Organizational resilience capacity to extreme weather events (EWEs) has sparked a growth in scholarly attention over the past decade as an essential aspect in business continuity management, with supporting evidence for this claim to suggest that it retains a key role in successful responses to adverse situations, crises and shocks. Small and medium-sized enterprises (SMEs) are more vulnerable to face floods compared to their larger counterparts, so they are disproportionately affected by such extreme weather events. The limited resources at their disposal, the lack of time and skills all conduce to inadequate preparedness to challenges posed by floods. SMEs tend to plan in the short-term, reacting to circumstances as they arise and focussing on their very survival. Likewise, they share less formalised structures and codified policies while they are most usually owner-managed, resulting in a command-and-control management culture. Such characteristics result in them having limited opportunities to recover from flooding and quickly turnaround their operation from a loss making to a profit making one. Scholars frame the capacity of business entities to be resilient upon an EWE disturbance (such as flash floods) as the rate of recovery and restoration of organizational performance to pre-disturbance conditions, the amount of disturbance (i.e. threshold level) a business can absorb before losing structural and/or functional components that will alter or cease operation, as well as the extent to which the organization maintains its function (i.e. impact resistance) before performance levels are driven to zero. Nevertheless, while it seems to be accepted as an essential trait of firms effectively transcending uncertain conditions, research deconstructing the enabling conditions and/or inhibitory factors of SMEs resilience capacity to natural hazards is still sparse, fragmentary and mostly fuelled by anecdotal evidence or normative assumptions. Focusing on the individual level of analysis, i.e. the individual enterprise and its endeavours to succeed, the emergent picture from this relatively new research strand delineates the specification of variables, conceptual relationships or dynamic boundaries of resilience capacity components in an attempt to provide prescriptions for policy-making as well as business management. This study will present the development of a flood resilience capacity index (FRCI) and its application to Greek SMEs. The proposed composite indicator pertains to cognitive, behavioral/managerial and contextual factors that influence an enterprise’s ability to shape effective responses to meet flood challenges. Through the proposed indicator-based approach, an analytical framework is set forth that will help standardize such assessments with the overarching aim of reducing the vulnerability of SMEs to flooding. This will be achieved by identifying major internal and external attributes explaining resilience capacity which is particularly important given the limited resources these enterprises have and that they tend to be primary sources of vulnerabilities in supply chain networks, generating Single Points of Failure (SPOF).

Keywords: Floods, Small & Medium-Sized enterprises, organizational resilience capacity, index development

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Authors: Nassim Bessaad, Qilian Bao, Zhao Jiangkang

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The fiber optics gyroscope in the strap-down inertial navigation system (FOG-SINS) suffers from precision degradation due to the influence of random errors. In this work, an enhanced Allan variance (AV) stochastic modeling method combined with discrete wavelet transform (DWT) for signal denoising is implemented to estimate the random process in the FOG signal. Furthermore, we devise a measurement-based iterative adaptive Sage-Husa nonlinear filter with augmented states to integrate a star tracker sensor with SINS. The proposed filter adapts the measurement noise covariance matrix based on the available data. Moreover, the enhanced stochastic modeling scheme is invested in tuning the process noise covariance matrix and the augmented state Gauss-Markov process parameters. Finally, the effectiveness of the proposed filter is investigated by employing the collected data in laboratory conditions. The result shows the filter's improved accuracy in comparison with the conventional Kalman filter (CKF).

Keywords: inertial navigation, adaptive filtering, star tracker, FOG

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Authors: Yazhi Huang, Jing Yang, Dingge Ying, Yan Zhang, Vorasuk Shotelersuk, Nattiya Hirankarn, Pak Chung Sham, Yu Lung Lau, Wanling Yang

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Human leukocyte antigen (HLA) typing from next generation sequencing (NGS) data has the potential for applications in clinical laboratories and population genetic studies. Here we introduce a novel technique for HLA typing from NGS data based on read-mapping using a comprehensive reference panel containing all known HLA alleles and de novo assembly of the gene-specific short reads. An accurate HLA typing at high-digit resolution was achieved when it was tested on publicly available NGS data, outperforming other newly-developed tools such as HLAminer and PHLAT.

Keywords: human leukocyte antigens, next generation sequencing, whole exome sequencing, HLA typing

Procedia PDF Downloads 670

Authors: Davoud Beheshtizadeh, Farzin Malekpour

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The progress of technology and producing new machinery have made a big change in excavation operations and construction of underground structures. The limitations of space and some other economic, politic and military considerations gained the attention of most developed and developing countries towards the construction of these structures for mine, military, and development objectives. Underground highways, tunnels, subways, oil reservoir resources, fuels, nuclear wastes burying reservoir and underground stores are increasingly developing and being used in these countries. The existence and habitability of the cities depend on these underground installations or in other words these vital arteries. Stopping the flow of water, gas leakage and explosion, collapsing of sewage paths, etc., resulting from the earthquake are among the factors that can severely harm the environment and increase the casualty. Lack of sewage network and complete stoppage of the flow of water in Bam (Iran) is a good example of this kind. In this paper, we investigate the effect of wave orientation on structures and deformation of them and the effect of faulting on underground structures, and then, we study resistance of reinforced concrete against earthquake, simulate two different samples, analyze the result and point out the importance of paying attention to underground installations.

Keywords: underground structures, earthquake, underground installations, axial deformations

Procedia PDF Downloads 197

Authors: Ram Dhani chauhan

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Tribology is a term that was developed from the Greek words ‘tribos’ (rubbing) and ‘logy’ (knowledge). In other words, a study of wear, friction and lubrication of material is known as Tribology. In groundwater irrigation, the life of submersible pump components like impeller, bush and wear ring will depend upon the wear and corrosion resistance of casted material. Leaded tin bronze (LTB) is an easily castable material with good mechanical properties and tribological behaviour and is utilised in submersible pumps at large. It has been investigated that, as Sn content increases from 4-8 wt. % in LTB alloys, the hardness of the alloys increases and the wear rate decreases. Similarly, a composite of copper with 3% wt. Graphite (threshold limit of mix) has a lower COF (coefficient of friction) and the lowest wear rate. In LTB alloys, in the initial low-speed range, wear increases and in the higher range, it was found that wear rate decreases.

Keywords: coefficent of friction, coefficient of wear, tribology, leaded tin bronze

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Authors: Safa Adi

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This paper will consider the problem of sequential mining patterns embedded in a database by handling the time constraints as defined in the GSP algorithm (level wise algorithms). We will compare two previous approaches GTC and PSP, that resumes the general principles of GSP. Furthermore this paper will discuss PG-hybrid algorithm, that using PSP and GTC. The results show that PSP and GTC are more efficient than GSP. On the other hand, the GTC algorithm performs better than PSP. The PG-hybrid algorithm use PSP algorithm for the two first passes on the database, and GTC approach for the following scans. Experiments show that the hybrid approach is very efficient for short, frequent sequences.

Keywords: database, GTC algorithm, PSP algorithm, sequential patterns, time constraints

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Authors: Lorenzo Gontrani, Marilena Carbone, Domenica Tommasa Donia, Elvira Maria Bauer, Pietro Tagliatesta

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One of the fields where DES shows remarkable added values is the synthesis Of inorganic materials, in particular nanoparticles. In this field, the higher- ent and highly-tunable nano-homogeneities of DES structure give origin to a marked templating effect, a precious role that has led to the recent bloom of a vast number of studies exploiting these new synthesis media to prepare Nanomaterials and composite structures of various kinds. In this contribution, the most recent developments in the field will be reviewed, and some ex-citing examples of novel metal oxide nanoparticles syntheses using non-toxic type-IV Deep Eutectic Solvents will be described. The prepared materials possess nanometric dimensions and show flower-like shapes. The use of the pre- pared nanoparticles as fluorescent materials for the detection of various contaminants is under development.

Keywords: metal deep eutectic solvents, nanoparticles, inorganic synthesis, type IV DES, lamellar

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Authors: Thomas P. Roper, Brad Forbes, Jurij Karlovšek

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Shear displacement along bedding defects is a well-recognised behaviour when tunnelling and mining in stratified rock. This deformation can affect the durability and integrity of installed rock bolts. In-situ monitoring of rock bolt deformation under bedding shear cannot be accurately derived from traditional strain gauge bolts as sensors are too large and spaced too far apart to accurately assess concentrated displacement along discrete defects. A possible solution to this is the use of fiber optic technologies developed for precision monitoring. Distributed Optic Sensor (DOS) embedded rock bolts were installed in a tunnel project with the aim of measuring the bolt deformation profile under significant shear displacements. This technology successfully measured the 3D strain distribution along the bolts when subjected to bedding shear and resolved the axial and lateral strain constituents in order to determine the deformational geometry of the bolts. The results are compared well with the current visual method for monitoring shear displacement using borescope holes, considering this method as suitable.

Keywords: distributed optical strain sensing, rock bolt, bedding shear, sandstone tunnel

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Authors: Abas Mohsenzadeh, Tariq Bashir, Waseen Tahir, Ulf Stigh, Mikael Skrifvars, Kim Bolton

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The area of artificial muscles has received significant attention from many research domains including soft robotics, biomechanics and smart textiles in recent years. Poly(vinylidene fluoride) (PVDF) has been used to form artificial muscles since it contracts upon heating when under load. In this study, PVDF fibers were produced by melt spinning technique at different solid state draw ratios and then actuation mechanism for PVDF tie molecules within the semicrystalline region of PVDF polymer has been investigated using molecular dynamics simulations. Tie molecules are polymer chains that link two (or more) crystalline regions in semicrystalline polymers. The changes in fiber length upon heating have been investigated using a novel simulation technique. The results show that conformational changes of the tie molecules from the longer all-trans conformation at low temperature (β structure) to the shorter conformation (α structure) at higher temperature accrue by increasing the temperature. These results may be applied to understand the actuation observed for PVDF upon heating.

Keywords: poly(vinylidene fluoride), molecular dynamics, simulation, actuators, tie molecules, semicrystalline

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Authors: Ekeh Greg

Abstract:

Learning has been part of human existence from time immemorial. The aim of every learning is to know the truth. In education, it is desirable that true knowledge is imparted and imbibed. For this to be achieved, there is need for honesty, in this context, academic honesty among students, especially in e-learning. This is an ethical issue since honesty bothers on human conduct. However, research findings have shown that academic honesty has remained a big challenge to online learners, especially among the university students. This is worrisome since the university education is the final education system and a gateway to life in the wider society after schooling. If they are practicing honesty in their academic life, it is likely that they will practice honesty in the in the society, thereby bringing positive contributions to the society wherever they find themselves. With this in mind, the significance of this study becomes obvious. On grounds of this significance, this paper focuses on strategies that are adjudged certain to enhance the practice of honesty in e-learning so as to enable learners to be well equipped to contribute to the society through honest ways. The aim of the paper is to contribute to the efforts of instilling the consciousness and practice of honesty in the minds and hearts of learners. This will, in turn, promote effective teaching and learning, academic high standard, competence and self-confidence in university education. Philosophical methods of conceptual analysis, clarification, description and prescription are adopted for the study. Philosophical perspective is chosen so as to ground the paper on the basis of rationality rather than emotional sentiments and biases emanating from cultural, religious and ethnic differences and orientations. Such sentiments and biases can becloud objective reasoning and sound judgment. A review of related literature is also carried out. The findings show that academic honesty in e-learning is a cherished value, but it is bedeviled by some challenges, such as care-free attitude on the part of students and absence of monitoring. The findings also show that despite the challenges facing academic honesty, strategies such as self-discipline, determination, hard work, imbibing ethical and philosophical principles, among others, can certainly enhance the practice of honesty in e-learning among university students. The paper, therefore, concludes that these constitute strategies for enhancing academic honesty among students. Consequently, it is suggested that instructors, school counsellors and other stakeholders should endeavour to see that students are helped to imbibe these strategies and put them into practice. Students themselves are enjoined to cherish honesty in their academic pursuit and avoid short-cuts. Short-cuts can only lead to mediocrity and incompetence on the part of the learners, which may have long adverse consequences, both on themselves and others.

Keywords: academic, ethical, philosophical, strategies

Procedia PDF Downloads 84

Authors: C. P. Providakis, G. M. Angeli, M. J. Favvata, N. A. Papadopoulos, C. E. Chalioris, C. G. Karayannis

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An effort for the detection of damages in the reinforcement bars of reinforced concrete members using PZTs is presented. The damage can be the result of excessive elongation of the steel bar due to steel yielding or due to local steel corrosion. In both cases the damage is simulated by considering reduced diameter of the rebar along the damaged part of its length. An integration approach based on both electromechanical admittance methodology and guided wave propagation technique is used to evaluate the artificial damage on the examined longitudinal steel bar. Two actuator PZTs and a sensor PZT are considered to be bonded on the examined steel bar. The admittance of the Sensor PZT is calculated using COMSOL 3.4a. Fast Furrier Transformation for a better evaluation of the results is employed. An effort for the quantification of the damage detection using the root mean square deviation (RMSD) between the healthy condition and damage state of the sensor PZT is attempted. The numerical value of the RSMD yields a level for the difference between the healthy and the damaged admittance computation indicating this way the presence of damage in the structure. Experimental measurements are also presented.

Keywords: concrete reinforcement, damage detection, electromechanical admittance, experimental measurements, finite element method, guided waves, PZT

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Authors: Tatjana Kochetkova

Abstract:

This paper explores the pivotal role of environmental education, specifically outdoor education, in facilitating a psychological connection to nature among young adults. This research aims to contribute to building an empirical and conceptual basis of ecopsychology by providing a picture of psyche-nature interaction. It presents the results of the four-day connection-to-nature workshop. It intends to find out the effects of the awareness of nature on subjective well-being and perception of the meaning of life. This led to finding a battery-recharging effect of nature and the influence of nature at four levels of awareness: external physical perception, internal (bodily) sensation, emotions, and existential meaning. The research on the psychological bond of humans with the natural environment, the subject of ecopsychology, is still in its infancy. However, despite several courageous and fruitful attempts, there are still no direct answers to the fundamental questions about the way in which the natural environment influences humans and the specific role of nature in the human psyche. The urge to address this question was the primary reason for the current experiment. The methodology of this study was taken from the study of Patterson, and from White and Hendee. The methodology included a series of assignments on the perception of nature (the exercises are described in the attachment). Experiences were noted in a personal diary, which we used later for analysis. There are many trustworthy claims that contact with nature has positive effects on human subjective well-being and that it is of essential psychological and spiritual value. But, there is a need for more support and theoretical explanation for this phenomenon. As a contribution to filling these gaps, this qualitative study was conducted. The aim of this study is to explore the psychological effects of short-term awareness of wilderness on one’s subjective well-being and on one’s sense of the meaning of life. This specific study is based on the more general hypothesis that there are positive relationships between the experience of wilderness and the development of the self, feelings of community, and spiritual development. It restricted the study of the psychological effects of short term stay in nature to two variables (subjective well-being and the sense of meaning of life). The study aimed at (i) testing the hypothesis that there are positive effects of the awareness of wilderness on the subjective sense of well-being and meaning in life, (ii) understanding the nature of the psychological need for wilderness. Although there is a substantial amount of data on the psychological benefits of nature, we still lack a theory that explains the findings. The present research aims to contribute to such a theory. This is an experiment aimed specifically at the effects of nature on the sense of well-being and meaning in life.

Keywords: environmental education, psychological connection to nature, subjective well-being, symbolic meaning of nature, emotional reaction to nature, meaning of life

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Authors: K. B. Ghazaryan, R. A. Ghazaryan

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Based on the constitutive model and anti-plane equations of anisotropic elastic body of monoclinic symmetry we consider the problem of shear wave propagation in multi-layered disordered composite structure with point defect. Using transfer matrix method the analytic expression is obtained providing solutions of shear Floquet wave propagation in periodic disordered anisotropic structure. The usefulness of the obtained analytical expression was discussed also in reflection and refraction problems from multi-layered reflector as well as in vibration problem of multi-layered waveguides. Numerical results are presented highlighting the effects arising in disordered periodic structure due to defects of multi-layered structure.

Keywords: shear elastic waves, monoclinic anisotropic media, periodic structure, disordered multilayer laminae, multi-layered waveguide

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Authors: Vilma Deltuvaitė

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Comparisons of financial development across countries are central to answering many of the questions on factors leading to economic development. For this reason this study analyzes the implications of financial system’s development on country’s economic development. The aim of the article: to analyze the impact of financial system’s development on economic development. The following research methods were used: systemic, logical and comparative analysis of scientific literature, analysis of statistical data, time series model (Autoregressive Distributed Lag (ARDL) Model). The empirical results suggest about positive short and long term effect of stock market development on GDP per capita.

Keywords: banking sector, economic development, financial system’s development, stock market, private bond market

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Authors: Min Ju Kim, Beom Jin Park, Deuk Jae Sung, Na Yeon Han, Kichoon Sim

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Purpose: The purpose of this study is to determine the significant magnetic resonance (MR) imaging factors of lateral pelvic lymph node (LPLN) on the assessment of survival outcomes of neoadjuvant combined chemotherapy and radiation therapy (CRT) in patients with mid/low rectal cancer. Materials and Methods: The institutional review board approved this retrospective study of 63 patients with mid/low rectal cancer who underwent MR before and after CRT and patient consent was not required. Surgery performed within 4 weeks after CRT. The location of LPLNs was divided into following four groups; 1) common iliac, 2) external iliac, 3) obturator, and 4) internal iliac lymph nodes. The short and long axis diameters, numbers, shape (ovoid vs round), signal intensity (homogenous vs heterogenous), margin (smooth vs irregular), and diffusion-weighted restriction of LPLN were analyzed on pre- and post-CRT images. For treatment response using size, lymph node groups were defined as group 1) short axis diameter ≤ 5mm on both MR, group 2) > 5mm change into ≤ 5mm after CRT, and group 3) persistent size > 5mm before and after CRT. Clinical findings were also evaluated. The disease-free survival and overall survival rate were evaluated and the risk factors for survival outcomes were analyzed using cox regression analysis. Results: Patients in the group 3 (persistent size >5mm) showed significantly lower survival rates than the group 1 and 2 (Disease-free survival rates of 36.1% and 78.8, 88.8%, p < 0.001). The size response (group 1-3), multiplicity of LPLN, the level of carcinoembryonic antigen (CEA), patient’s age, T and N stage, vessel invasion, perineural invasion were significant factors affecting disease-free survival rate or overall survival rate using univariate analysis (p < 0.05). The persistent size (group 3) and multiplicity of LPLN were independent risk factors among MR imaging features influencing disease-free survival rate (HR = 10.087, p < 0.05; HR = 4.808, p < 0.05). Perineural invasion and T stage were shown as independent histologic risk factors (HR = 16.594, p < 0.05; HR = 15.891, p < 0.05). Conclusion: The persistent size greater than 5mm and multiplicity of LPLN on both pre- and post-MR after CRT were significant MR factors affecting survival outcomes in the patients with mid/low rectal cancer.

Keywords: rectal cancer, MRI, lymph node, combined chemoradiotherapy

Procedia PDF Downloads 155

Authors: C. P. Providakis, G. M. Angeli, M. J. Favvata, N. A. Papadopoulos, C. E. Chalioris, C. G. Karayannis

Abstract:

An effort for the detection of damages in the reinforcement bars of reinforced concrete members using PZTs is presented. The damage can be the result of excessive elongation of the steel bar due to steel yielding or due to local steel corrosion. In both cases the damage is simulated by considering reduced diameter of the rebar along the damaged part of its length. An integration approach based on both electro-mechanical admittance methodology and guided wave propagation technique is used to evaluate the artificial damage on the examined longitudinal steel bar. Two actuator PZTs and a sensor PZT are considered to be bonded on the examined steel bar. The admittance of the Sensor PZT is calculated using COMSOL 3.4a. Fast Furrier Transformation for a better evaluation of the results is employed. An effort for the quantification of the damage detection using the root mean square deviation (RMSD) between the healthy condition and damage state of the sensor PZT is attempted. The numerical value of the RSMD yields a level for the difference between the healthy and the damaged admittance computation indicating this way the presence of damage in the structure. Experimental measurements are also presented.

Keywords: concrete reinforcement, damage detection, electromechanical admittance, experimental measurements, finite element method, guided waves, PZT

Procedia PDF Downloads 295

Authors: Ling-Ling E, Lin Feng, Hong-Chen Liu, Dong-Sheng Wang, Zhanping Shi, Juncheng Wang, Wei Luo, Yan Lv

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The objective of this study was to compare the effects of the two calcium phosphate composite scaffolds on the attachment, proliferation and osteogenic differentiation of rabbit dental pulp stem cells (DPSCs). One nano-hydroxyapatite/collagen/poly (L-lactide) (nHAC/PLA), imitating the composition and the micro-structure characteristics of the natural bone, was made by Beijing Allgens Medical Science & Technology Co., Ltd. (China). The other beta-tricalcium phosphate (β-TCP), being fully interoperability globular pore structure, was provided by Shanghai Bio-lu Biomaterials Co, Ltd. (China). We compared the absorption water rate and the protein adsorption rate of two scaffolds and the characterization of DPSCs cultured on the culture plate and both scaffolds under osteogenic differentiation media (ODM) treatment. The constructs were then implanted subcutaneously into the back of severe combined immunodeficient (SCID) mice for 8 and 12 weeks to compare their bone formation capacity. The results showed that the ODM-treated DPSCs expressed osteocalcin (OCN), bone sialoprotein (BSP), type I collagen (COLI) and osteopontin (OPN) by immunofluorescence staining. Positive alkaline phosphatase (ALP) staining, calcium deposition and calcium nodules were also observed on the ODM-treated DPSCs. The nHAC/PLA had significantly higher absorption water rate and protein adsorption rate than ß-TCP. The initial attachment of DPSCs seeded onto nHAC/PLA was significantly higher than that onto ß-TCP; and the proliferation rate of the cells was significantly higher than that of ß-TCP on 1, 3 and 7 days of cell culture. DPSCs+ß-TCP had significantly higher ALP activity, calcium/phosphorus content and mineral formation than DPSCs+nHAC/PLA. When implanted into the back of SCID mice, nHAC/PLA alone had no new bone formation, newly formed mature bone and osteoid were only observed in β-TCP alone, DPSCs+nHAC/PLA and DPSCs+β-TCP, and this three groups displayed increased bone formation over the 12-week period. The percentage of total bone formation area had no difference between DPSCs+β-TCP and DPSCs+nHAC/PLA at each time point，but the percentage of mature bone formation area of DPSCs+β-TCP was significantly higher than that of DPSCs+nHAC/PLA. Our results demonstrated that the DPSCs on nHAC/PLA had a better proliferation and that the DPSCs on β-TCP had a more mineralization in vitro, much more newly formed mature bones in vivo were presented in DPSCs+β-TCP group. These findings have provided a further knowledge that scaffold architecture has a different influence on the attachment, proliferation and differentiation of cells. This study may provide insight into the clinical periodontal bone tissue repair with DPSCs+β-TCP construct.

Keywords: dental pulp stem cells, nano-hydroxyapatite/collagen/poly(L-lactide), beta-tricalcium phosphate, periodontal tissue engineering, bone regeneration

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Authors: S. Amanpour, F. Mohamadian, S. A. Tabatabai

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With the number of accidents and fatalities in recent years can be concluded that Iran is the status of road accidents, remains in a crisis. Investigate the causes of such incidents in all countries is a necessity. By doing this research, the results of the number and type of accidents and the location of the crash will be available. It is possible to prioritize economic and rational solutions to fix the flaws in the way of short-term the results are all the more strict rules about the desire to have black spots and cursory glance at the change of but results in long-term are desired to change the system or increase the width of the path or add extra track. In general, the relationship between the analysis of the accidents and near police statistics is the number of accidents in one year. This could prove the accuracy of the analysis done.

Keywords: traffic, IHSDM, crash, modeling, Khuzestan

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Authors: Shilpa Kapoor, Namrata Yaduvanshi, Pooja Pawar, Sadhna Singh

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A Three Body Interaction Potential (TBIP) model is developed to study the high pressure phase transition of SrS having NaCl (B1) structure at room temperature. This model includes the long range Columbic, three body interaction forces, short range overlap forces operative up to next nearest neighbors and zero point energy effects. We have investigated the phase transition with pressure, volume collapse and second order elastic constants and found results well suited with available experimental data.

Keywords: phase transition, second order elastic constants, three body interaction forces, volume collapses

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Authors: Mohammad Abu-Shaira, Weishi Shi

Abstract:

Adaptive learning, a commonly employed solution to drift, involves updating predictive models online during their operation to react to concept drifts, thereby serving as a critical component and natural extension for online learning systems that learn incrementally from each example. This paper introduces LSTM-SCCM “Long Short-Term Memory Stream Cruise Control Method”, a drift adaptation-as-a-service framework for online learning. LSTM-SCCM automates drift adaptation through prompt detection, drift magnitude quantification, dynamic hyperparameter tuning, performing shortterm optimization and model recalibration for immediate adjustments, and, when necessary, conducting long-term model recalibration to ensure deeper enhancements in model performance. LSTM-SCCM is incorporated into a suite of cutting-edge online regression models, assessing their performance across various types of concept drift using diverse datasets with varying characteristics. The findings demonstrate that LSTM-SCCM represents a notable advancement in both model performance and efficacy in handling concept drift occurrences. LSTM-SCCM stands out as the sole framework adept at effectively tackling concept drifts within regression scenarios. Its proactive approach to drift adaptation distinguishes it from conventional reactive methods, which typically rely on retraining after significant degradation to model performance caused by drifts. Additionally, LSTM-SCCM employs an in-memory approach combined with the Self-Adjusting Memory (SAM) architecture to enhance real-time processing and adaptability. The framework incorporates variable thresholding techniques and does not assume any particular data distribution, making it an ideal choice for managing high-dimensional datasets and efficiently handling large-scale data. Our experiments, which include abrupt, incremental, and gradual drifts across both low- and high-dimensional datasets with varying noise levels, and applied to four state-of-the-art online regression models, demonstrate that LSTM-SCCM is versatile and effective, rendering it a valuable solution for online regression models to address concept drift.

Keywords: automated drift detection and adaptation, concept drift, hyperparameters optimization, online and adaptive learning, regression

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Authors: Bibi Asma, Rokonozzaman Reza, Majharul Islam, Muhammad Foyez Ahmed, Mohammad Tayub

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Since the beginning of human civilization, natural dyes have been adored in textile coloration due to their non-hazardous nature compared to commercial dyes, recyclability, safety and a plethora of congenial attributes. Henna is an herb leaf that is used to color hands in Muslim fes-tivals, hence it is a part of tradition. In this study, Henna (Lawsoniainermis L.) has been used to dye nylon fabric with and without mordants. In the case of the mordanting process, metal chela-tion of Ferrous Sulphate (FeSO₄) and Copper Sulphate (CuSO₄) was used. The dyeing behavior of natural dye Henna with or without mordant was examined by analysis of colorimetric properties of color, depth of shade measurement and colorfastness properties of dyed fabric sample was also assessed as well. The study shows dye absorption of fiber has considerably increased by using mordants which in return exhibits a greater depth of shade, also the dyed samples demonstrated excellent fastness ratings in wash fastness, rubbing fastness, and Perspiration fastness with little to no change in color obtained.

Keywords: sustainable dyeing, henna, mordanting, metal chelation

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Authors: Raouf Mbarki, Fadi Al Khatib, Malek Adouni

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Knee collateral ligaments play a significant role in restraining excessive frontal motion (varus/valgus rotations). In this investigation, a multiscale frame was developed based on structural hierarchies of the collateral ligaments starting from the bottom (tropocollagen molecule) to up where the fibred reinforced structure established. Experimental data of failure tensile test were considered as the principal driver of the developed model. This model was calibrated statistically using Bayesian calibration due to the high number of unknown parameters. Then the model is scaled up to fit the real structure of the collateral ligaments and simulated under realistic boundary conditions. Predications have been successful in describing the observed transient response of the collateral ligaments during tensile test under pre- and post-damage loading conditions. Collateral ligaments maximum stresses and strengths were observed near to the femoral insertions, a results that is in good agreement with experimental investigations. Also for the first time, damage initiation and propagation were documented with this model as a function of the cross-link density between tropocollagen molecules.

Keywords: multiscale model, tropocollagen, fibrils, ligaments commas

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Authors: Sagardeep Talukdar, Riki Dutta, Gautam Kumar Saharia, Sudipta Nandy

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In non-linear optics, the Fokas-Lenells equation (FLE) is a well-known integrable equation that describes how ultrashort pulses move across the optical fiber. It admits localized wave solutions, just like any other integrable equation. We apply the Hirota bilinearization method to obtain the soliton solution of FLE. The proposed bilinearization makes use of an auxiliary function. We apply the method to FLE with a vanishing boundary condition, that is, to obtain a bright soliton solution. We have obtained bright 1-soliton and 2-soliton solutions and propose a scheme for obtaining an N-soliton solution. We have used an additional parameter that is responsible for the shift in the position of the soliton. Further analysis of the 2-soliton solution is done by asymptotic analysis. In the non-vanishing boundary condition, we obtain the dark 1-soliton solution. We discover that the suggested bilinearization approach, which makes use of the auxiliary function, greatly simplifies the process while still producing the desired outcome. We think that the current analysis will be helpful in understanding how FLE is used in nonlinear optics and other areas of physics.

Keywords: asymptotic analysis, fokas-lenells equation, hirota bilinearization method, soliton

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Authors: M. Shirinbayan, J. Fitoussi, N. Abbasnezhad, A. Lucas, A. Tcharkhtchi

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Sheet Molding Compounds (SMCs) with special microstructures are very attractive to use in automobile structures especially when they are accidentally subjected to collision type accidents because of their high energy absorption capacity. These are materials designated as standard SMC, Advanced Sheet Molding Compounds (A-SMC), Low-Density SMC (LD-SMC) and etc. In this study, testing methods have been performed to compare the mechanical responses and damage phenomena of SMC, LD-SMC, and A-SMC under quasi-static and high strain rate tensile tests. The paper also aims at investigating the effect of an initial pre-damage induced by fatigue on the tensile dynamic behavior of A-SMC. In the case of SMCs and A-SMCs, whatever the fibers orientation and applied strain rate are, the first observed phenomenon of damage corresponds to decohesion of the fiber-matrix interface which is followed by coalescence and multiplication of these micro-cracks and their propagations. For LD-SMCs, damage mechanisms depend on the presence of Hollow Glass Microspheres (HGM) and fibers orientation.

Keywords: SMC, Sheet Molding Compound, LD-SMC, Low-Density SMC, A-SMC, Advanced Sheet Molding Compounds, HGM, Hollow Glass Microspheres, damage

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Authors: Santhosh K. S. Annayappa, Nupur Pruthi

Abstract:

The region of dentate nucleus is a common site for various pathologies like hematomas, tumours, etc. We aimed to study in detail the relationship of this region with the vermis, especially the pyramid using microscopic fibre dissection technique. To achieve this aim, 20 cerebellar hemispheres were studied from the 11 cerebellums. Dissection was performed using wooden spatulas and micro dissectors under a microscope following Klingler’s preservation technique. The relationship between the pyramid of vermis and the dentate nucleus was studied in detail. A similar relationship was studied on the MRI of randomly selected trigeminal neuralgia patients and correlated with anatomical findings. Results show the mean distance of the lateral margin of the dentate nucleus from the midline on anatomic specimens was 21.4 ± 1.8 mm (19-25 mm) and 23.4 ± 3.4 mm (15-29 mm) on right and left side, respectively. Similar measurements made on the MRI were 22.97 ± 2.0 mm (20.03-26.15 mm) on the right side and 23.98 ± 2.1 mm (21.47-27.67 mm) on the left side. The amount of white matter dissection required to reach the dentate nucleus at the pyramidal attachment area was 7.3 ± 1.0 mm (6-9 mm) on the right side and 6.8 ± 1.4 mm (5-10 mm) on the left side. It was concluded that the pyramid of vermis has a constant relationship with the dentate nucleus and can be used as an excellent landmark during surgery to localise the dentate nucleus on the suboccipital surface.

Keywords: fiber dissection, micro neurosurgery, the dentate nucleus of cerebellum, the pyramid of vermis

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Authors: Nizamuddin Zainuddin, Adam Mohd Saifudin, Ahmad Yusni Bahaudin, Mohd Hanizan Zalazilah, Roslan Jamaluddin

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Students’ enhanced experience through simulation is a crucial factor that brings reality to the classroom. The enhanced experience is all about developing, enriching and applications of a generic process flow in the field of logistics and transportations. As educational technology has improved, the effective use of simulations has greatly increased to the point where simulations should be considered a valuable, mainstream pedagogical tool. Additionally, in this era of ongoing (some say never-ending) assessment, simulations offer a rich resource for objective measurement and comparisons. Simulation is not just another in the long line of passing fads (or short-term opportunities) in educational technology. It is rather a real key to helping our students understand the world. It is a way for students to acquire experience about how things and systems in the world behave and react, without actually touching them. In short, it is about interactive pretending. Simulation is all about representing the real world which includes grasping the complex issues and solving intricate problems. Therefore, it is crucial before stimulate the real process of inbound and outbound logistics and transportation a generic process flow shall be developed. The paper will be focusing on the validization of the process flow by looking at the inputs gains from the sample. The sampling of the study focuses on multi-national and local manufacturing companies, third party companies (3PL) and government agency, which are selected in Peninsular Malaysia. A simulation flow chart was proposed in the study that will be the generic flow in logistics and transportation. A qualitative approach was mainly conducted to gather data in the study. It was found out from the study that the systems used in the process of outbound and inbound are System Application Products (SAP) and Material Requirement Planning (MRP). Furthermore there were some companies using Enterprises Resources Planning (ERP) and Electronic Data Interchange (EDI) as part of the Suppliers Own Inventories (SOI) networking as a result of globalized business between one countries to another. Computerized documentations and transactions were all mandatory requirement by the Royal Custom and Excise Department. The generic process flow will be the basis of developing a simulation program that shall be used in the classroom with the objective of further enhanced the students’ learning experience. Thus it will contributes to the body of knowledge on the enrichment of the student’s employability and also shall be one of the way to train new workers in the logistics and transportation filed.

Keywords: enhancement, simulation, process flow, logistics, transportation

Procedia PDF Downloads 331