Search results for: density functional theoretical
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 9299

Search results for: density functional theoretical

7529 Impact of Air Pressure and Outlet Temperature on Physicochemical and Functional Properties of Spray-dried Skim Milk Powder

Authors: Adeline Meriaux, Claire Gaiani, Jennifer Burgain, Frantz Fournier, Lionel Muniglia, Jérémy Petit

Abstract:

Spray-drying process is widely used for the production of dairy powders for food and pharmaceuticals industries. It involves the atomization of a liquid feed into fine droplets, which are subsequently dried through contact with a hot air flow. The resulting powders permit transportation cost reduction and shelf life increase but can also exhibit various interesting functionalities (flowability, solubility, protein modification or acid gelation), depending on operating conditions and milk composition. Indeed, particles porosity, surface composition, lactose crystallization, protein denaturation, protein association or crust formation may change. Links between spray-drying conditions and physicochemical and functional properties of powders were investigated by a design of experiment methodology and analyzed by principal component analysis. Quadratic models were developed, and multicriteria optimization was carried out by the use of genetic algorithm. At the time of abstract submission, verification spray-drying trials are ongoing. To perform experiments, milk from dairy farm was collected, skimmed, froze and spray-dried at different air pressure (between 1 and 3 bars) and outlet temperature (between 75 and 95 °C). Dry matter, minerals content and proteins content were determined by standard method. Solubility index, absorption index and hygroscopicity were determined by method found in literature. Particle size distribution were obtained by laser diffraction granulometry. Location of the powder color in the Cielab color space and water activity were characterized by a colorimeter and an aw-value meter, respectively. Flow properties were characterized with FT4 powder rheometer; in particular compressibility and shearing test were performed. Air pressure and outlet temperature are key factors that directly impact the drying kinetics and powder characteristics during spray-drying process. It was shown that the air pressure affects the particle size distribution by impacting the size of droplet exiting the nozzle. Moreover, small particles lead to more cohesive powder and less saturated color of powders. Higher outlet temperature results in lower moisture level particles which are less sticky and can explain a spray-drying yield increase and the higher cohesiveness; it also leads to particle with low water activity because of the intense evaporation rate. However, it induces a high hygroscopicity, thus, powders tend to get wet rapidly if they are not well stored. On the other hand, high temperature provokes a decrease of native serum proteins which is positively correlated to gelation properties (gel point and firmness). Partial denaturation of serum proteins can improve functional properties of powder. The control of air pressure and outlet temperature during the spray-drying process significantly affects the physicochemical and functional properties of powder. This study permitted to better understand the links between physicochemical and functional properties of powder, to identify correlations between air pressure and outlet temperature. Therefore, mathematical models have been developed and the use of genetic algorithm will allow the optimization of powder functionalities.

Keywords: dairy powders, spray-drying, powders functionalities, design of experiment

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7528 A Framework for Assessing and Implementing Ecological-Based Adaptation Solutions in Urban Areas of Shanghai

Authors: Xin Li

Abstract:

The uncertainty and the complexity of the urban environment combining with the threat of climate change are contributing factors to the vulnerability in multiple-dimensions in Chinese megacities, especially in Shanghai. The urban area occupied high valuable technological infrastructure and density buildings is under the threats of climate change and can provide insufficient ecological service to remain the trade-off on urban sustainable development. Urban ecological-based adaptation (UEbA) combines practices and theoretical work and integrates ecological services into multiple-layers of urban environment planning in order to reduce the impact of the complexity and uncertainty. To understand and to respond to the challenges in the urban level, this paper considers Shanghai as the research objective. It is necessary that its urban adaptation strategies should be reflected and contain the concept and knowledge of EbA. In this paper, we firstly use software to illustrates the visualizing patterns and trends of UEBA research in the current 10 years. Specifically, Citespace software was used for interpreting the significant hubs, landmarks points of peer-reviewed literature on the context of ecological service research in recent 10 years. Secondly, 135 evidence-based EbA literature were reviewed for categorizing the methodologies and framework of evidence-based EbA by the systematic map protocol. Finally, a conceptual framework combined with culture, economic and social components was developed in order to assess the current adaptation strategies in Shanghai. This research founds that the key to reducing urban vulnerability does not only focus on co-benefit arguments but also should pay more attention to the concept of trade-off. This research concludes that the designed framework can provide key knowledge and indicates the essential gap as a valuable tool against climate variability in the process of urban adaptation in Shanghai.

Keywords: urban ecological-based adaptation, climate change, sustainable development, climate variability

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7527 GeneNet: Temporal Graph Data Visualization for Gene Nomenclature and Relationships

Authors: Jake Gonzalez, Tommy Dang

Abstract:

This paper proposes a temporal graph approach to visualize and analyze the evolution of gene relationships and nomenclature over time. An interactive web-based tool implements this temporal graph, enabling researchers to traverse a timeline and observe coupled dynamics in network topology and naming conventions. Analysis of a real human genomic dataset reveals the emergence of densely interconnected functional modules over time, representing groups of genes involved in key biological processes. For example, the antimicrobial peptide DEFA1A3 shows increased connections to related alpha-defensins involved in infection response. Tracking degree and betweenness centrality shifts over timeline iterations also quantitatively highlight the reprioritization of certain genes’ topological importance as knowledge advances. Examination of the CNR1 gene encoding the cannabinoid receptor CB1 demonstrates changing synonymous relationships and consolidating naming patterns over time, reflecting its unique functional role discovery. The integrated framework interconnecting these topological and nomenclature dynamics provides richer contextual insights compared to isolated analysis methods. Overall, this temporal graph approach enables a more holistic study of knowledge evolution to elucidate complex biology.

Keywords: temporal graph, gene relationships, nomenclature evolution, interactive visualization, biological insights

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7526 Proposition of an Integrative Model for Assessing the Effectiveness of the Performance Management System

Authors: Mariana L. de Araújo, Pedro P. M. Menezes

Abstract:

Research on strategic human resource management (SHRM) has made progress in the last few decades, showing a relationship between policies and practices of human resource management (HRM) and improving organizational results. That's because demonstrating the effectiveness of any HRM or other organizational practice, which means the extent that this can operate as a tool to achieve organizational performance, is a complex and arduous task to execute. Even today, there isn't consensus about "effectiveness," and the tools to measure the effectiveness are disconnected and not convincing. It is not different from the performance management system (PMS) effectiveness. A disproportionate focus on specific criteria adopted and an accumulation of studies that don't relate to the others, which damages the development of the field. Therefore, it aimed to evaluate the effectiveness of the PMS through models, dimensions, criteria, and measures. The objective of this study is to propose a theoretical-integrative model for evaluating PMS based on the literature in the PMS field. So, the PRISMA protocol was applied to carry out a systematic review, resulting in 57 studies. After performing the content analysis, we identified six dimensions: learning, societal impact, reaction, financial results, operational results and transfer, and 22 categories. In this way, a theoretical-integrative model for assessing the effectiveness of PMS was proposed based on the findings of this study, in which it was possible to confirm that the effectiveness construct is somewhat complex when viewing that most of the reviewed studies considered multiple dimensions in their assessment. In addition, we identified that the most immediate and proximal results of PMS are the most adopted by the studies; conversely, the studies adopted less distal outcomes to assess the effectiveness of PMS. Another finding of this research is that the reviewed studies predominantly analyze from the individual or psychological perspective, even when it comes to criteria whose phenomena are at an organizational level. Therefore, this study converges with a trend recently identified when referring to a process of "psychologization" in which GP studies, in general, have demonstrated macro results of the GP system from an individual perspective. Therefore, given the identification of a methodological pattern, the predominant influence of individual and psychological aspects in studies on HRM in administration is highlighted, demonstrated by the reflection on the practically absolute way of measuring the effectiveness of PMS from perceptual and subjective measures. Therefore, based on the recognition of the patterns identified, the model proposed to promote studies on the subject more broadly and profoundly to broaden and deepen the perspective of the field of management's interests so that the evaluation of the effectiveness of PMS can promote inputs on the impact of the PMS system in organizational performance. Finally, the findings encourage reflections on assessing the effectiveness of PMS through the theoretical-integrative model developed so that the field can promote new theoretical and practical perspectives.

Keywords: performance management, strategic human resource management, effectiveness, organizational performance

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7525 The Main Characteristics of Destructive Motivation

Authors: Elen Gasparyan, Naira Hakobyan

Abstract:

One of the leading factors determining the effectiveness of work in a modern organization is the motivation of its employees. In the scientific psychological literature, this phenomenon is understood mainly as constructive forms of motivation and the search for ways to increase it. At the same time, the motivation of employees can sometimes lead to a decrease in the productivity of the organization, i.e., destructive motivation is usually not considered from the point of view of various motivational theories. This article provides an analysis of various forms of destructive motivation of employees. These forms include formalism in labor behavior, inadequate assessment of the work done, and an imbalance of personal and organizational interests. The destructive motivation of personnel has certain negative consequences both for the employees themselves and for the entire organization - it leads to a decrease in the rate of production and the quality of products or services, increased conflict in the behavior of employees, etc. Currently, there is an increase in scientific interest in the study of destructive motivation. The subject of psychological research is not only modern socio-psychological processes but also the achievements of scientific thought in the field of theories of motivation and management. This article examines the theoretical approaches of J. S. Adams and Porter-Lawler, provides an analysis of theoretical concepts, and emphasizes the main characteristics of the destructiveness of motivation. Destructive work motivation is presented at the macro, meso, and micro levels. These levels express various directions of development of motivation stimuli, such as social, organizational, and personal ones. At the macro level, the most important characteristics of destructive motivation are the high-income gap between employers and employees, а high degree of unemployment, weak social protection of workers, non-compliance by employers with labor legislation, and emergencies. At the organizational level, the main characteristics are decreasing the diversity of work and insufficient work conditions. At the personal level, the main characteristic of destructive motivation is a discrepancy between personal and organizational interests. A comparative analysis of the theoretical and methodological foundations of the study of motivation makes it possible to identify not only the main characteristics of destructive motivation but also to determine the contours of psychological counseling to reduce destructiveness in the behavior of employees.

Keywords: destructive, motivation, organization, behavior

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7524 An Investigation on Fresh and Hardened Properties of Concrete While Using Polyethylene Terephthalate (PET) as Aggregate

Authors: Md. Jahidul Islam, A. K. M. Rakinul Islam, M. Salamah Meherier

Abstract:

This study investigates the suitability of using plastic, such as polyethylene terephthalate (PET), as a partial replacement of natural coarse and fine aggregates (for example, brick chips and natural sand) to produce lightweight concrete for load bearing structural members. The plastic coarse aggregate (PCA) and plastic fine aggregate (PFA) were produced from melted polyethylene terephthalate (PET) bottles. Tests were conducted using three different water–cement (w/c) ratios, such as 0.42, 0.48, and 0.57, where PCA and PFA were used as 50% replacement of coarse and fine aggregate respectively. Fresh and hardened properties of concrete have been compared for natural aggregate concrete (NAC), PCA concrete (PCC) and PFA concrete (PFC). The compressive strength of concrete at 28 days varied with the water–cement ratio for both the PCC and PFC. Between PCC and PFC, PFA concrete showed the highest compressive strength (23.7 MPa) at 0.42 w/c ratio and also the lowest compressive strength (13.7 MPa) at 0.57 w/c ratio. Significant reduction in concrete density was mostly observed for PCC samples, ranging between 1977–1924 kg/m³. With the increase in water–cement ratio PCC achieved higher workability compare to both NAC and PFC. It was found that both the PCA and PFA contained concrete achieved the required compressive strength to be used for structural purpose as partial replacement of the natural aggregate; but to obtain the desired lower density as lightweight concrete the PCA is most suited.

Keywords: polyethylene terephthalate, plastic aggregate, concrete, fresh and hardened properties

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7523 Comparison of Different Activators Impact on the Alkali-Activated Aluminium-Silicate Composites

Authors: Laura Dembovska, Ina Pundiene, Diana Bajare

Abstract:

Alkali-activated aluminium-silicate composites (AASC) can be used in the production of innovative materials with a wide range of properties and applications. AASC are associated with low CO₂ emissions; in the production process, it is possible to use industrial by-products and waste, thereby minimizing the use of a non-renewable natural resource. This study deals with the preparation of heat-resistant porous AASC based on chamotte for high-temperature applications up to 1200°C. Different fillers, aluminium scrap recycling waste as pores forming agent and alkali activation with 6M sodium hydroxide (NaOH) and potassium hydroxide (KOH) solution were used. Sodium hydroxide (NaOH) is widely used for the synthesis of AASC compared to potassium hydroxide (KOH), but comparison of using different activator for geopolymer synthesis is not well established. Changes in chemical composition of AASC during heating were identified and quantitatively analyzed by using DTA, dimension changes during the heating process were determined by using HTOM, pore microstructure was examined by SEM, and mineralogical composition of AASC was determined by XRD. Lightweight porous AASC activated with NaOH have been obtained with density in range from 600 to 880 kg/m³ and compressive strength from 0.8 to 2.7 MPa, but for AAM activated with KOH density was in range from 750 to 850 kg/m³ and compressive strength from 0.7 to 2.1 MPa.

Keywords: alkali activation, alkali activated materials, elevated temperature application, heat resistance

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7522 A Study of Transferable Strategies in Multilanguage Learning

Authors: Zixi You

Abstract:

With the demand of multilingual speakers increasing in the job market, multi-language learning programs have become more and more popular among undergraduate students. A study on multi-language learning strategies is therefore highly demanded on both practical and theoretical levels. Based on previous classification of learning strategies in SLA, and an investigation of BA Modern Language program students (with post-A level L2 and ab initio L3 learning experience from year one), this study explores and compares different types of learning strategies used by multi-language speakers and learners, transferable learning strategies between L2 and L3, and factors affecting the transfer. The results indicate that all the 23 types of learning strategies of L2 are employed when learning L3 from ab initio level, yet with different tendencies. Learning strategy transfer from L2 to L3 (i.e., the learners attribute the applying of these L3 learning strategies to be a direct result of their L2 learning experience) are observed in all 23 types of learning strategies. Comparatively, six types of “cognitive strategies” have higher transfer tendency than others. With regard to the failure of the transfer of some particular L2 strategies and the development of independent L3 strategies of individual learners, factors such as language proficiency, language typology and learning environment have played important roles among others. The presentation of this study will provide audiences with detailed data, insightful analysis and discussion on both theoretical and practical aspects of multi-language learning that will benefit both students and educators.

Keywords: learning strategy, multi-language acquisition, second language acquisition, strategy transfer

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7521 Synthesis of Multi-Functional Iron Oxide Nanoparticles for Targeted Drug Delivery in Cancer Treatment

Authors: Masome Moeni, Roya Abedizadeh, Elham Aram, Hamid Sadeghi-Abandansari, Davood Sabour, Robert Menzel, Ali Hassanpour

Abstract:

Significant number of studies and preclinical research in formulation of cancer nano-pharmaceutics have led to an improvement in cancer care. Nonetheless, the antineoplastic agents have ‘failed to live up to its promise’ since their clinical performance is moderately low. For almost ninety years, iron oxide nanoparticles (IONPS) have managed to keep its reputation in clinical application due to their low toxicity, versatility and multi-modal capabilities. Drug Administration approved utilization of IONPs for diagnosis of cancer as contrast media in magnetic resonance imaging, as heat mediator in magnetic hyperthermia and for the treatment of iron deficiency. Furthermore, IONPs have high drug-loading capacity, which makes them good candidates as therapeutic agent transporters. There are yet challenges to overcome for successful clinical application of IONPs, including stability of drug and poor delivery, which might lead to (i) drug resistance, (ii) shorter blood circulation time, and (iii) rapid elimination and adverse side effects from the system. In this study, highly stable and super paramagnetic IONPs were prepared for efficient and targeted drug delivery in cancer treatment. The synthesis procedure was briefly involved the production of IONPs via co-precipitation followed by coating with tetraethyl orthosilicate and 3-aminopropylethoxysilane and grafting with folic acid for stability targeted purposes and controlled drug release. Physiochemical and morphological properties of modified IONPs were characterised using different analytical techniques. The resultant IONPs exhibited clusters of 10 nm spherical shape crystals with less than 100 nm size suitable for drug delivery. The functionalized IONP showed mesoporous features, high stability, dispersibility and crystallinity. Subsequently, the functionalized IONPs were successfully loaded with oxaliplatin, a chemotherapeutic agent, for a controlled drug release in an actively targeting cancer cells. FT-IR observations confirmed presence of oxaliplatin functional groups, while ICP-MS results verified the drug loading was ~ 1.3%.

Keywords: cancer treatment, chemotherapeutic agent, drug delivery, iron oxide, multi-functional nanoparticle

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7520 The Effects of Exercise Training on LDL Mediated Blood Flow in Coronary Artery Disease: A Systematic Review

Authors: Aziza Barnawi

Abstract:

Background: Regular exercise reduces risk factors associated with cardiovascular diseases. Over the past decade, exercise interventions have been introduced to reduce the risk of and prevent coronary artery disease (CAD). Elevated low-density lipoproteins (LDL) contribute to the formation of atherosclerosis, its manifestations on the endothelial narrow the coronary artery and affect the endothelial function. Therefore, flow-mediated dilation (FMD) technique is used to assess the function. The results of previous studies have been inconsistent and difficult to interpret across different types of exercise programs. The relationship between exercise therapy and lipid levels has been extensively studied, and it is known to improve the lipid profile and endothelial function. However, the effectiveness of exercise in altering LDL levels and improving blood flow is controversial. Objective: This review aims to explore the evidence and quantify the impact of exercise training on LDL levels and vascular function by FMD. Methods: Electronic databases were searched PubMed, Google Scholar, Web of Science, the Cochrane Library, and EBSCO using the keywords: “low and/or moderate aerobic training”, “blood flow”, “atherosclerosis”, “LDL mediated blood flow”, “Cardiac Rehabilitation”, “low-density lipoproteins”, “flow-mediated dilation”, “endothelial function”, “brachial artery flow-mediated dilation”, “oxidized low-density lipoproteins” and “coronary artery disease”. The studies were conducted for 6 weeks or more and influenced LDL levels and/or FMD. Studies with different intensity training and endurance training in healthy or CAD individuals were included. Results: Twenty-one randomized controlled trials (RCTs) (14 FMD and 7 LDL studies) with 776 participants (605 exercise participants and 171 control participants) met eligibility criteria and were included in the systematic review. Endurance training resulted in a greater reduction in LDL levels and their subfractions and a better FMD response. Overall, the training groups showed improved physical fitness status compared with the control groups. Participants whose exercise duration was ≥150 minutes /week had significant improvement in FMD and LDL levels compared with those with <150 minutes/week.Conclusion: In conclusion, although the relationship between physical training, LDL levels, and blood flow in CAD is complex and multifaceted, there are promising results for controlling primary and secondary prevention of CAD by exercise. Exercise training, including resistance, aerobic, and interval training, is positively correlated with improved FMD. However, the small body of evidence for LDL studies (resistance and interval training) did not prove to be significantly associated with improved blood flow. Increasing evidence suggests that exercise training is a promising adjunctive therapy to improve cardiovascular health, potentially improving blood flow and contributing to the overall management of CAD.

Keywords: exercise training, low density lipoprotein, flow mediated dilation, coronary artery disease

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7519 Modeling and Optimization of a Microfluidic Electrochemical Cell for the Electro-Reduction of CO₂ to CH₃OH

Authors: Barzin Rajabloo, Martin Desilets

Abstract:

First, an electrochemical model for the reduction of CO₂ into CH₃OH is developed in which mass and charge transfer, reactions at the surface of the electrodes and fluid flow of the electrolyte are considered. This mathematical model is developed in COMSOL Multiphysics® where both secondary and tertiary current distribution interfaces are coupled to consider concentrations and potentials inside different parts of the cell. Constant reaction rates are assumed as the fitted parameters to minimize the error between experimental data and modeling results. The model is validated through a comparison with experimental data in terms of faradaic efficiency for production of CH₃OH, the current density in different applied cathode potentials as well as current density in different electrolyte flow rates. The comparison between model outputs and experimental measurements shows a good agreement. The model indicates the higher hydrogen evolution in comparison with CH₃OH production as well as mass transfer limitation caused by CO₂ concentration, which are consistent with findings in the literature. After validating the model, in the second part of the study, some design parameters of the cell, such as cathode geometry and catholyte/anolyte channel widths, are modified to reach better performance and higher faradaic efficiency of methanol production.

Keywords: carbon dioxide, electrochemical reduction, methanol, modeling

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7518 Nanoscale Photo-Orientation of Azo-Dyes in Glassy Environments Using Polarized Optical Near-Field

Authors: S. S. Kharintsev, E. A. Chernykh, S. K. Saikin, A. I. Fishman, S. G. Kazarian

Abstract:

Recent advances in improving information storage performance are inseparably linked with circumvention of fundamental constraints such as the supermagnetic limit in heat assisted magnetic recording, charge loss tolerance in solid-state memory and the Abbe’s diffraction limit in optical storage. A substantial breakthrough in the development of nonvolatile storage devices with dimensional scaling has been achieved due to phase-change chalcogenide memory, which nowadays, meets the market needs to the greatest advantage. A further progress is aimed at the development of versatile nonvolatile high-speed memory combining potentials of random access memory and archive storage. The well-established properties of light at the nanoscale empower us to use them for recording optical information with ultrahigh density scaled down to a single molecule, which is the size of a pit. Indeed, diffraction-limited optics is able to record as much information as ~1 Gb/in2. Nonlinear optical effects, for example, two-photon fluorescence recording, allows one to decrease the extent of the pit even more, which results in the recording density up to ~100 Gb/in2. Going beyond the diffraction limit, due to the sub-wavelength confinement of light, pushes the pit size down to a single chromophore, which is, on average, of ~1 nm in length. Thus, the memory capacity can be increased up to the theoretical limit of 1 Pb/in2. Moreover, the field confinement provides faster recording and readout operations due to the enhanced light-matter interaction. This, in turn, leads to the miniaturization of optical devices and the decrease of energy supply down to ~1 μW/cm². Intrinsic features of light such as multimode, mixed polarization and angular momentum in addition to the underlying optical and holographic tools for writing/reading, enriches the storage and encryption of optical information. In particular, the finite extent of the near-field penetration, falling into a range of 50-100 nm, gives the possibility to perform 3D volume (layer-to-layer) recording/readout of optical information. In this study, we demonstrate a comprehensive evidence of isotropic-to-homeotropic phase transition of the azobenzene-functionalized polymer thin film exposed to light and dc electric field using near-field optical microscopy and scanning capacitance microscopy. We unravel a near-field Raman dichroism of a sub-10 nm thick epoxy-based side-chain azo-polymer films with polarization-controlled tip-enhanced Raman scattering. In our study, orientation of azo-chromophores is controlled with a bias voltage gold tip rather than light polarization. Isotropic in-plane and homeotropic out-of-plane arrangement of azo-chromophores in glassy environment can be distinguished with transverse and longitudinal optical near-fields. We demonstrate that both phases are unambiguously visualized by 2D mapping their local dielectric properties with scanning capacity microscopy. The stability of the polar homeotropic phase is strongly sensitive to the thickness of the thin film. We make an analysis of α-transition of the azo-polymer by detecting a temperature-dependent phase jump of an AFM cantilever when passing through the glass temperature. Overall, we anticipate further improvements in optical storage performance, which approaches to a single molecule level.

Keywords: optical memory, azo-dye, near-field, tip-enhanced Raman scattering

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7517 The Impact of Blended Learning on the Perception of High School Learners Towards Entrepreneurship

Authors: Rylyne Mande Nchu, Robertson Tengeh, Chux Iwu

Abstract:

Blended learning is a global phenomenon and is essential to many institutes of learning as an additional method of teaching that complements more traditional methods of learning. In this paper, the lack of practice of a blended learning approach to entrepreneurship education and how it impacts learners' perception of being entrepreneurial. E-learning is in its infancy within the secondary and high school sectors in South Africa. The conceptual framework of the study is based on theoretical aspects of systemic-constructivist learning implemented in an interactive online learning environment in an entrepreneurship education subject. The formative evaluation research was conducted implementing mixed methods of research (quantitative and qualitative) and it comprised a survey of high school learners and informant interviewing with entrepreneurs. Theoretical analysis of literature provides features necessary for creating interactive blended learning environments to be used in entrepreneurship education subject. Findings of the study show that learners do not always objectively evaluate their capacities. Special attention has to be paid to the development of learners’ computer literacy as well as to the activities that would bring online learning to practical training. Needs analysis shows that incorporating blended learning in entrepreneurship education may have a positive perception of entrepreneurship.

Keywords: blended learning, entrepreneurship education, entrepreneurship intention, entrepreneurial skills

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7516 The Effects of Electron Trapping by Electron-Ecoustic Waves Excited with Electron Beam

Authors: Abid Ali Abid

Abstract:

One-dimensional (1-D) particle-in-cell (PIC) electrostatic simulations are carried out to investigate the electrostatic waves, whose constituents are hot, cold and beam electrons in the background of motionless positive ions. In fact, the electrostatic modes excited are electron acoustic waves, beam driven waves as well as Langmuir waves. It is assessed that the relevant plasma parameters, for example, hot electron temperature, beam electron drift speed, and the electron beam density significantly modify the electrostatics wave's profiles. In the nonlinear stage, the wave-particle interaction becomes more evident and the waves have obtained its saturation level. Consequently, electrons become trapped in the waves and trapping vortices are clearly formed. Because of this trapping vortices and mixing of the electrons in phase space, finally, lead to electrons thermalization. It is observed that for the high-density value of the beam-electron, the solitary waves having a bipolar form of the electric field. These solitons are the nonlinear Brenstein-Greene and Kruskal wave mode that attributes the trapping of electrons potential well of phase-space hole. These examinations revealed that electrostatic waves have been exited in beam-plasma model and producing waves having broad-frequency ranges, which may clarify the broadband electrostatic noise (BEN) spectrum studied in the auroral zone.

Keywords: electron acoustic waves, trapping of cold electron, Langmuir waves, particle-in cell simulation

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7515 Evolution of Nettlespurge Oil Mud for Drilling Mud System: A Comparative Study of Diesel Oil and Nettlespurge Oil as Oil-Based Drilling Mud

Authors: Harsh Agarwal, Pratikkumar Patel, Maharshi Pathak

Abstract:

Recently the low prices of Crude oil and increase in strict environmental regulations limit limits the use of diesel based muds as these muds are relatively costlier and toxic, as a result disposal of cuttings into the eco-system is a major issue faced by the drilling industries. To overcome these issues faced by the Oil Industry, an attempt has been made to develop oil-in-water emulsion mud system using nettlespurge oil. Nettlespurge oil could be easily available and its cost is around ₹30/litre which is about half the price of diesel in India. Oil-based mud (OBM) was formulated with Nettlespurge oil extracted from Nettlespurge seeds using the Soxhlet extraction method. The formulated nettlespurge oil mud properties were analysed with diesel oil mud properties. The compared properties were rheological properties, yield point and gel strength, and mud density and filtration loss properties, fluid loss and filter cake. The mud density measurement showed that nettlespurge OBM was slightly higher than diesel OBM with mud density values of 9.175 lb/gal and 8.5 lb/gal, respectively, at barite content of 70 g. Thus it has a higher lubricating property. Additionally, the filtration loss test results showed that nettlespurge mud fluid loss volumes, oil was 11 ml, compared to diesel oil mud volume of 15 ml. The filtration loss test indicated that the nettlespurge oil mud with filter cake thickness of 2.2 mm had a cake characteristic of thin and squashy while the diesel oil mud resulted in filter cake thickness of 2.7 mm with cake characteristic of tenacious, rubbery and resilient. The filtration loss test results showed that nettlespurge oil mud fluid loss volumes was much less than the diesel based oil mud. The filtration loss test indicated that the nettlespurge oil mud filter cake thickness less than the diesel oil mud filter cake thickness. So Low formation damage and the emulsion stability effect was analysed with this experiment. The nettlespurge oil-in-water mud system had lower coefficient of friction than the diesel oil based mud system. All the rheological properties have shown better results relative to the diesel based oil mud. Therefore, with all the above mentioned factors and with the data of the conducted experiment we could conclude that the Nettlespurge oil based mud is economically and well as eco-logically much more feasible than the worn out and shabby diesel-based oil mud in the Drilling Industry.

Keywords: economical feasible, ecological feasible, emulsion stability, nettle spurge oil, rheological properties, soxhlet extraction method

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7514 Study of Operating Conditions Impact on Physicochemical and Functional Properties of Dairy Powder Produced by Spray-drying

Authors: Adeline Meriaux, Claire Gaiani, Jennifer Burgain, Frantz Fournier, Lionel Muniglia, Jérémy Petit

Abstract:

Spray-drying process is widely used for the production of dairy powders for food and pharmaceuticals industries. It involves the atomization of a liquid feed into fine droplets, which are subsequently dried through contact with a hot air flow. The resulting powders permit transportation cost reduction and shelf life increase but can also exhibit various interesting functionalities (flowability, solubility, protein modification or acid gelation), depending on operating conditions and milk composition. Indeed, particles porosity, surface composition, lactose crystallization, protein denaturation, protein association or crust formation may change. Links between spray-drying conditions and physicochemical and functional properties of powders were investigated by a design of experiment methodology and analyzed by principal component analysis. Quadratic models were developed, and multicriteria optimization was carried out by the use of genetic algorithm. At the time of abstract submission, verification spray-drying trials are ongoing. To perform experiments, milk from dairy farm was collected, skimmed, froze and spray-dried at different air pressure (between 1 and 3 bars) and outlet temperature (between 75 and 95 °C). Dry matter, minerals content and proteins content were determined by standard method. Solubility index, absorption index and hygroscopicity were determined by method found in literature. Particle size distribution were obtained by laser diffraction granulometry. Location of the powder color in the Cielab color space and water activity were characterized by a colorimeter and an aw-value meter, respectively. Flow properties were characterized with FT4 powder rheometer; in particular, compressibility and shearing test were performed. Air pressure and outlet temperature are key factors that directly impact the drying kinetics and powder characteristics during spray-drying process. It was shown that the air pressure affects the particle size distribution by impacting the size of droplet exiting the nozzle. Moreover, small particles lead to more cohesive powder and less saturated color of powders. Higher outlet temperature results in lower moisture level particles which are less sticky and can explain a spray-drying yield increase and the higher cohesiveness; it also leads to particle with low water activity because of the intense evaporation rate. However, it induces a high hygroscopicity, thus, powders tend to get wet rapidly if they are not well stored. On the other hand, high temperature provokes a decrease of native serum proteins, which is positively correlated to gelation properties (gel point and firmness). Partial denaturation of serum proteins can improve functional properties of powder. The control of air pressure and outlet temperature during the spray-drying process significantly affects the physicochemical and functional properties of powder. This study permitted to better understand the links between physicochemical and functional properties of powder to identify correlations between air pressure and outlet temperature. Therefore, mathematical models have been developed, and the use of genetic algorithm will allow the optimization of powder functionalities.

Keywords: dairy powders, spray-drying, powders functionalities, design of experiment

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7513 Evaluation of Technology Tools for Mathematics Instruction by Novice Elementary Teachers

Authors: Christopher J. Johnston

Abstract:

This paper presents the finding of a research study in which novice (first and second year) elementary teachers (grades Kindergarten – six) evaluated various mathematics Virtual Manipulatives, websites, and Applets (tools) for use in mathematics instruction. Participants identified the criteria they used for evaluating these types of resources and provided recommendations for or against five pre-selected tools. During the study, participants participated in three data collection activities: (1) A brief Likert-scale survey which gathered information about their attitudes toward technology use; (2) An identification of criteria for evaluating technology tools; and (3) A review of five pre-selected technology tools in light of their self-identified criteria. Data were analyzed qualitatively using four theoretical categories (codes): Software Features (41%), Mathematics (26%), Learning (22%), and Motivation (11%). These four theoretical categories were then grouped into two broad categories: Content and Instruction (Mathematics and Learning), and Surface Features (Software Features and Motivation). These combined, broad categories suggest novice teachers place roughly the same weight on pedagogical features as they do technological features. Implications for mathematics teacher educators are discussed, and suggestions for future research are provided.

Keywords: mathematics education, novice teachers, technology, virtual manipulatives

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7512 Optimization of Thermopile Sensor Performance of Polycrystalline Silicon Film

Authors: Li Long, Thomas Ortlepp

Abstract:

A theoretical model for the optimization of thermopile sensor performance is developed for thermoelectric-based infrared radiation detection. It is shown that the performance of polycrystalline silicon film thermopile sensor can be optimized according to the thermoelectric quality factor, sensor layer structure factor, and sensor layout geometrical form factor. Based on the properties of electrons, phonons, grain boundaries, and their interactions, the thermoelectric quality factor of polycrystalline silicon is analyzed with the relaxation time approximation of the Boltzmann transport equation. The model includes the effect of grain structure, grain boundary trap properties, and doping concentration. The layer structure factor is analyzed with respect to the infrared absorption coefficient. The optimization of layout design is characterized by the form factor, which is calculated for different sensor designs. A double-layer polycrystalline silicon thermopile infrared sensor on a suspended membrane has been designed and fabricated with a CMOS-compatible process. The theoretical approach is confirmed by measurement results.

Keywords: polycrystalline silicon, relaxation time approximation, specific detectivity, thermal conductivity, thermopile infrared sensor

Procedia PDF Downloads 145
7511 Breast Cancer Risk Factors: A Big Data Analysis of Black and White Women in the USA

Authors: Tejasvi Parupudi, Mochen Li, Lakshya Mittal, Ignacio G. Camarillo, Raji Sundararajan

Abstract:

With breast cancer becoming a global pandemic, it is very important to assess a woman’s risk profile accurately in a timely manner. Providing an estimate of the risk of developing breast cancer to a woman gives her an opportunity to consider options to decrease this risk. Women at low risk may be suggested yearly screenings whereas women with a high risk of developing breast cancer would be candidates for aggressive surveillance. Fortunately, there is a set of risk factors that are used to predict the probability of a woman being diagnosed with breast cancer in the future. Studying risk factors and understanding how they correlate to cancer is important for early diagnosis, prevention and reducing mortality rates. The effect of crucial risk factors among black and white women was compared in this study. The various risk factors analyzed include breast density, age, cancer in a first-degree relative, menopausal status, body mass index (BMI) and prior breast cancer diagnosis, etc. Breast density, age at first full-term birth and BMI were utilized in this study as important risk factors for the comparison of incidence rates between women of black and white races in the USA. Understanding the differences could lead to the development of solutions to reduce disparity in mortality rates among black women by improving overall access to care.

Keywords: big data, breast cancer, risk factors, incidence rates, mortality, race

Procedia PDF Downloads 276
7510 Exploring the 1,3-Dipolar Cycloaddition Reaction between Nitrilimine and 6-Methyl-4,5-dihydropyridazin-3(2h)-one through MEDT and Molecular Docking Analysis

Authors: Zineb Ouahdi

Abstract:

Spirocyclic compound derivatives, with their unique heterocyclic motifs, serve as a continual source of inspiration in the pursuit of developing potential therapeutic agents. These compounds are diverse in their chemical structures; some have fully saturated skeletons, while others are partially unsaturated. Nevertheless, these compounds share a characteristic feature with natural products - the presence of at least one heteroatom in one of their rings. The inclusion of a C = O dipolarophile in pyridazinones imparts an exciting aspect for 1,3-dipolar cycloaddition reactions, the focal point of our study. Our research has involved a detailed theoretical investigation of the reaction between ethyl (Z)-2-bromo-2-(2-(p-tolyl)hydrazono)acetate and 6-methyl-4,5-dihydropyridazine-3(2H)-one. This has been accomplished using the DFT/B3LYP/6-31g(d,p) method, intending to illuminate the chemical pathway of this reaction. The chemical reactivity theories we used for this purpose included FMO, TS, and local and global indices derived from conceptual DFT. The theoretical framework outlined in this study allowed us to propose a reaction mechanism for cycloaddition reactions. It also enabled the identification of the potential activities of the analyzed compounds (P1, P2, P3, P4, P5, and P6) against the major protease of the coronavirus disease (COVID-19). This was achieved using various computational tools, including AutoDock Tools, Autodock Vina, Autodock 4, and PYRX.

Keywords: MEDT, pyridazin, cycloaddition, FMO, DFT, docking

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7509 Soil Properties and Yam Performance as Influenced by Poultry Manure and Tillage on an Alfisol in Southwestern Nigeria

Authors: E. O. Adeleye

Abstract:

Field experiments were conducted to investigate the effect of soil tillage techniques and poultry manure application on the soil properties and yam (Dioscorea rotundata) performance in Ondo, southwestern Nigeria for two farming seasons. Five soil tillage techniques, namely ploughing (P), ploughing plus harrowing (PH), manual ridging (MR), manual heaping (MH) and zero-tillage (ZT) each combined with and without poultry manure at the rate of 10 tha-1 were investigated. Data were obtained on soil properties, nutrient uptake, growth and yield of yam. Soil moisture content, bulk density, total porosity and post harvest soil chemical characteristics were significantly (p>0.05) influenced by soil tillage-manure treatments. Addition of poultry manure to the tillage techniques in the study increased soil total porosity, soil moisture content and reduced soil bulk density. Poultry manure improved soil organic matter, total nitrogen, available phosphorous, exchangeable Ca, k, leaf nutrients content of yam, yam growth and tuber yield relative to tillage techniques plots without poultry manure application. It is concluded that the possible deleterious effect of tillage on soil properties, growth and yield of yam on an alfisol in southwestern Nigeria can be reduced by combining tillage with poultry manure.

Keywords: poultry manure, tillage, soil chemical properties, yield

Procedia PDF Downloads 448
7508 Risk of Cardiovascular Diseases: Evaluation of Serum Lipid Profiles in Urban and Rural Population of Sindh

Authors: Mohsin Ali Baloch, Saira Baloch

Abstract:

Objective: The aim of this study was to evaluate the levels of serum lipid profiles in Urban and Rural Population of Sindh, to indicate the existing risk of cardiovascular diseases. Material and Methods: Study was conducted at Liaquat University of Medical & Health Sciences, in the cities of Jamshoro and Hyderabad of Sindh. Blood samples from 300 healthy individuals were collected in fasting condition, out them 100 were from rural population, 100 were urban while 100 were used as control group. The biochemistry of these samples was obtained by the analysis of total Cholesterol, high density lipoprotein Cholesterol (HDL), low-density lipoprotein Cholesterol (LDL) and Triglycerides using kit method on Analyzer Clinical Chemistry. Results and Conclusion: Serum levels of total cholesterol, Triglycerides, and LDL cholesterol were significantly raised in the rural and urban males, whereas HDL cholesterol was decreased as compared to the Healthy controls that indicated significant risk of CVD. Urban population was with more risk of CVD and male gender in both groups was at more risk. The worst lipid profile in gender wise distribution was observed in male gender of urban population with highest Total Cholesterol/HDL Ratio while female gender also shown moderate risk of CVD with highest LDL/HDL Ratio.

Keywords: cardiovascular diseases, lipid profiles, urban and rural population, LDL/HDL Ratio

Procedia PDF Downloads 409
7507 The Reproducibility and Repeatability of Modified Likelihood Ratio for Forensics Handwriting Examination

Authors: O. Abiodun Adeyinka, B. Adeyemo Adesesan

Abstract:

The forensic use of handwriting depends on the analysis, comparison, and evaluation decisions made by forensic document examiners. When using biometric technology in forensic applications, it is necessary to compute Likelihood Ratio (LR) for quantifying strength of evidence under two competing hypotheses, namely the prosecution and the defense hypotheses wherein a set of assumptions and methods for a given data set will be made. It is therefore important to know how repeatable and reproducible our estimated LR is. This paper evaluated the accuracy and reproducibility of examiners' decisions. Confidence interval for the estimated LR were presented so as not get an incorrect estimate that will be used to deliver wrong judgment in the court of Law. The estimate of LR is fundamentally a Bayesian concept and we used two LR estimators, namely Logistic Regression (LoR) and Kernel Density Estimator (KDE) for this paper. The repeatability evaluation was carried out by retesting the initial experiment after an interval of six months to observe whether examiners would repeat their decisions for the estimated LR. The experimental results, which are based on handwriting dataset, show that LR has different confidence intervals which therefore implies that LR cannot be estimated with the same certainty everywhere. Though the LoR performed better than the KDE when tested using the same dataset, the two LR estimators investigated showed a consistent region in which LR value can be estimated confidently. These two findings advance our understanding of LR when used in computing the strength of evidence in handwriting using forensics.

Keywords: confidence interval, handwriting, kernel density estimator, KDE, logistic regression LoR, repeatability, reproducibility

Procedia PDF Downloads 126
7506 Production of Buttermilk as a Bio-Active Functional Food by Utilizing Dairy Waste

Authors: Hafsa Tahir, Sanaullah Iqbal

Abstract:

Glactooligosaccharide (GOS) is a type of prebiotic which is mainly found in human milk. GOS belongs to those bacteria which stimulates the growth of beneficial bacteria in human intestines. The aim of the present study was to develop a value-added product by producing prebiotic (GOS) in buttermilk through trans galactosylation. Buttermilk is considered as an industrial waste which is discarded after the production of butter and cream. It contains protein, minerals, vitamins and a smaller amount of fat. Raw milk was pasteurized at 100º C for butter production and then trans galactosylation process was induced in the butter milk thus obtained to produce prebiotic GOS. Results showed that the enzyme (which was obtained from bacterial strain of Esecrshia coli and has a gene of Lactobacillus reuteri L103) concentration between 400-600µl/5ml can produce GOS in 30 minutes. Chemical analysis and sensory evaluation of plain and GOS containing buttermilk showed no remarkable difference in their composition. Furthermore, the shelf-life study showed that there was non-significant (P>0.05) difference in glass and pouch packaging of buttermilk. Buttermilk in pouch packaging maintained its stability for 6 days without the addition of preservatives. Therefore it is recommended that GOS enriched buttermilk which is generally considered as a processing waste in dairy manufacturing can be turned into a cost-effective nutritional functional food product. This will not only enhance the production efficiency of butter processing but also will create a new market opportunity for dairy manufacturers all over the world.

Keywords: buttermilk, galactooligosaccharide, shelf Life, transgalactosylation

Procedia PDF Downloads 292
7505 Development and Validation of a Coronary Heart Disease Risk Score in Indian Type 2 Diabetes Mellitus Patients

Authors: Faiz N. K. Yusufi, Aquil Ahmed, Jamal Ahmad

Abstract:

Diabetes in India is growing at an alarming rate and the complications caused by it need to be controlled. Coronary heart disease (CHD) is one of the complications that will be discussed for prediction in this study. India has the second most number of diabetes patients in the world. To the best of our knowledge, there is no CHD risk score for Indian type 2 diabetes patients. Any form of CHD has been taken as the event of interest. A sample of 750 was determined and randomly collected from the Rajiv Gandhi Centre for Diabetes and Endocrinology, J.N.M.C., A.M.U., Aligarh, India. Collected variables include patients data such as sex, age, height, weight, body mass index (BMI), blood sugar fasting (BSF), post prandial sugar (PP), glycosylated haemoglobin (HbA1c), diastolic blood pressure (DBP), systolic blood pressure (SBP), smoking, alcohol habits, total cholesterol (TC), triglycerides (TG), high density lipoprotein (HDL), low density lipoprotein (LDL), very low density lipoprotein (VLDL), physical activity, duration of diabetes, diet control, history of antihypertensive drug treatment, family history of diabetes, waist circumference, hip circumference, medications, central obesity and history of CHD. Predictive risk scores of CHD events are designed by cox proportional hazard regression. Model calibration and discrimination is assessed from Hosmer Lemeshow and area under receiver operating characteristic (ROC) curve. Overfitting and underfitting of the model is checked by applying regularization techniques and best method is selected between ridge, lasso and elastic net regression. Youden’s index is used to choose the optimal cut off point from the scores. Five year probability of CHD is predicted by both survival function and Markov chain two state model and the better technique is concluded. The risk scores for CHD developed can be calculated by doctors and patients for self-control of diabetes. Furthermore, the five-year probabilities can be implemented as well to forecast and maintain the condition of patients.

Keywords: coronary heart disease, cox proportional hazard regression, ROC curve, type 2 diabetes Mellitus

Procedia PDF Downloads 220
7504 Association of Neck Circumference as an Indicator of Upper Body Obesity with Cardio-Metabolic Risk Factors among First Degree Relatives of Diabetes Patients

Authors: Hadi Abdollahi, Bijan Iraj, Maryam Mirpourian, Behzad Shariatifar

Abstract:

Background: The aim of the present study was to determine the relationship between neck circumferences (NC), as an indicator of upper body obesity, with anthropometric and cardio-metabolic factors among the first degree relatives of diabetes patients. Materials and Methods: This cross-sectional study was performed on first degree relatives of diabetes patients (n = 213). Weight, height, waist circumference (WC), hip circumference (HC), systolic blood pressure (SBP), diastolic blood pressure (DBP) and NC were measured. Laboratory data included oral glucose tolerance test (OGTT) results, high density lipoprotein (HDL), low density lipoprotein, triglyceride (TG) and total cholesterol. Results: There was no difference in NC among different results of OGTT in men or women. Factors including weight, body mass index (BMI), WC and HC were strongly associated with NC in both genders (r = 0.420-0.711). NC was weakly associated with SBP in women (r = 0.195) and moderately with DBP in men (r = 0.314). Regarding lipid profile, HDL and TG were associated with NC only in women (r = −0.268-0.325). Conclusions: NC has a significant correlation with gender and anthropometric variables, including BMI, weight and waist and HCs in both men and women, but it does not differ significantly in patients with different status in OGTT.

Keywords: body mass index, cardiovascular, diabetes, neck circumference, obesity

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7503 Further Study of Mechanism of Contrasting Charge Transport Properties for Phenyl and Thienyl Substituent Organic Semiconductors

Authors: Yanan Zhu

Abstract:

Based on the previous work about the influence mechanism of the mobility difference of phenyl and thienyl substituent semiconductors, we have made further exploration towards to design high-performance organic thin-film transistors. The substituent groups effect plays a significant role in materials properties and device performance as well. For the theoretical study, simulation of materials property and crystal packing can supply scientific guidance for materials synthesis in experiments. This time, we have taken the computational methods to design a new material substituent with furan groups, which are the potential to be used in organic thin-film transistors and organic single-crystal transistors. The reorganization energy has been calculated and much lower than 2,6-diphenyl anthracene (DPAnt), which performs large mobility as more than 30 cm²V⁻¹s⁻¹. Moreover, the other important parameter, charge transfer integral is larger than DPAnt, which suggested the furan substituent material may get a much better charge transport data. On the whole, the mechanism investigation based on phenyl and thienyl assisted in designing novel materials with furan substituent, which is predicted to be an outperformed organic field-effect transistors.

Keywords: theoretical calculation, mechanism, mobility, organic transistors

Procedia PDF Downloads 138
7502 Stochastic Modeling for Parameters of Modified Car-Following Model in Area-Based Traffic Flow

Authors: N. C. Sarkar, A. Bhaskar, Z. Zheng

Abstract:

The driving behavior in area-based (i.e., non-lane based) traffic is induced by the presence of other individuals in the choice space from the driver’s visual perception area. The driving behavior of a subject vehicle is constrained by the potential leaders and leaders are frequently changed over time. This paper is to determine a stochastic model for a parameter of modified intelligent driver model (MIDM) in area-based traffic (as in developing countries). The parametric and non-parametric distributions are presented to fit the parameters of MIDM. The goodness of fit for each parameter is measured in two different ways such as graphically and statistically. The quantile-quantile (Q-Q) plot is used for a graphical representation of a theoretical distribution to model a parameter and the Kolmogorov-Smirnov (K-S) test is used for a statistical measure of fitness for a parameter with a theoretical distribution. The distributions are performed on a set of estimated parameters of MIDM. The parameters are estimated on the real vehicle trajectory data from India. The fitness of each parameter with a stochastic model is well represented. The results support the applicability of the proposed modeling for parameters of MIDM in area-based traffic flow simulation.

Keywords: area-based traffic, car-following model, micro-simulation, stochastic modeling

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7501 Investigation of Chemical Effects on the Lγ2,3 and Lγ4 X-ray Production Cross Sections for Some Compounds of 66dy at Photon Energies Close to L1 Absorption-edge Energy

Authors: Anil Kumar, Rajnish Kaur, Mateusz Czyzycki, Alessandro Migilori, Andreas Germanos Karydas, Sanjiv Puri

Abstract:

The radiative decay of Li(i=1-3) sub-shell vacancies produced through photoionization results in production of the characteristic emission spectrum comprising several X-ray lines, whereas non-radiative vacancy decay results in Auger electron spectrum. Accurate reliable data on the Li(i=1-3) sub-shell X-ray production (XRP) cross sections is of considerable importance for investigation of atomic inner-shell ionization processes as well as for quantitative elemental analysis of different types of samples employing the energy dispersive X-ray fluorescence (EDXRF) analysis technique. At incident photon energies in vicinity of the absorption edge energies of an element, the many body effects including the electron correlation, core relaxation, inter-channel coupling and post-collision interactions become significant in the photoionization of atomic inner-shells. Further, in case of compounds, the characteristic emission spectrum of the specific element is expected to get influenced by the chemical environment (coordination number, oxidation state, nature of ligand/functional groups attached to central atom, etc.). These chemical effects on L X-ray fluorescence parameters have been investigated by performing the measurements at incident photon energies much higher than the Li(i=1-3) sub-shell absorption edge energies using EDXRF spectrometers. In the present work, the cross sections for production of the Lk(k= γ2,3, γ4) X-rays have been measured for some compounds of 66Dy, namely, Dy2O3, Dy2(CO3)3, Dy2(SO4)3.8H2O, DyI2 and Dy metal by tuning the incident photon energies few eV above the L1 absorption-edge energy in order to investigate the influence of chemical effects on these cross sections in presence of the many body effects which become significant at photon energies close to the absorption-edge energies. The present measurements have been performed under vacuum at the IAEA end-station of the X-ray fluorescence beam line (10.1L) of ELETTRA synchrotron radiation facility (Trieste, Italy) using self-supporting pressed pellet targets (1.3 cm diameter, nominal thicknesses ~ 176 mg/cm2) of 66Dy compounds (procured from Sigma Aldrich) and a metallic foil of 66Dy (nominal thickness ~ 3.9 mg/cm2, procured from Good Fellow, UK). The present measured cross sections have been compared with theoretical values calculated using the Dirac-Hartree-Slater(DHS) model based fluorescence and Coster-Kronig yields, Dirac-Fock(DF) model based X-ray emission rates and two sets of L1 sub-shell photoionization cross sections based on the non-relativistic Hartree-Fock-Slater(HFS) model and those deduced from the self-consistent Dirac-Hartree-Fock(DHF) model based total photoionization cross sections. The present measured XRP cross sections for 66Dy as well as for its compounds for the L2,3 and L4 X-rays, are found to be higher by ~14-36% than the two calculated set values. It is worth to be mentioned that L2,3 and L4 X-ray lines are originated by filling up of the L1 sub-shell vacancies by the outer sub-shell (N2,3 and O2,3) electrons which are much more sensitive to the chemical environment around the central atom. The present observed differences between measured and theoretical values are expected due to combined influence of the many-body effects and the chemical effects.

Keywords: chemical effects, L X-ray production cross sections, Many body effects, Synchrotron radiation

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7500 Predicting Response to Cognitive Behavioral Therapy for Psychosis Using Machine Learning and Functional Magnetic Resonance Imaging

Authors: Eva Tolmeijer, Emmanuelle Peters, Veena Kumari, Liam Mason

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Cognitive behavioral therapy for psychosis (CBTp) is effective in many but not all patients, making it important to better understand the factors that determine treatment outcomes. To date, no studies have examined whether neuroimaging can make clinically useful predictions about who will respond to CBTp. To this end, we used machine learning methods that make predictions about symptom improvement at the individual patient level. Prior to receiving CBTp, 22 patients with a diagnosis of schizophrenia completed a social-affective processing task during functional MRI. Multivariate pattern analysis assessed whether treatment response could be predicted by brain activation responses to facial affect that was either socially threatening or prosocial. The resulting models did significantly predict symptom improvement, with distinct multivariate signatures predicting psychotic (r=0.54, p=0.01) and affective (r=0.32, p=0.05) symptoms. Psychotic symptom improvement was accurately predicted from relatively focal threat-related activation across hippocampal, occipital, and temporal regions; affective symptom improvement was predicted by a more dispersed profile of responses to prosocial affect. These findings enrich our understanding of the neurobiological underpinning of treatment response. This study provides a foundation that will hopefully lead to greater precision and tailoring of the interventions offered to patients.

Keywords: cognitive behavioral therapy, machine learning, psychosis, schizophrenia

Procedia PDF Downloads 275