Search results for: co-toxicity coefficient

Authors: S. O. Oyamakin, A. U. Chukwu

Abstract:

Richard's growth equation being a generalized logistic growth equation was improved upon by introducing an allometric parameter using the hyperbolic sine function. The integral solution to this was called hyperbolic Richard's growth model having transformed the solution from deterministic to a stochastic growth model. Its ability in model prediction was compared with the classical Richard's growth model an approach which mimicked the natural variability of heights/diameter increment with respect to age and therefore provides a more realistic height/diameter predictions using the coefficient of determination (R2), Mean Absolute Error (MAE) and Mean Square Error (MSE) results. The Kolmogorov-Smirnov test and Shapiro-Wilk test was also used to test the behavior of the error term for possible violations. The mean function of top height/Dbh over age using the two models under study predicted closely the observed values of top height/Dbh in the hyperbolic Richard's nonlinear growth models better than the classical Richard's growth model.

Keywords: height, Dbh, forest, Pinus caribaea, hyperbolic, Richard's, stochastic

Procedia PDF Downloads 480

Authors: B. K. Sahoo

Abstract:

Superior thermoelectric (TE) efficiency of AlₓIn₁₋ₓN /GaN heterostructure (HS) requires a minimum value of thermal conductivity (k). A smaller k would lead to even further increase of TE figure of merit (ZT). The built-in polarization (BIP) electric field of AlₓIn₁₋ₓN /GaN HS enhances S, and σ of the HS, however, the effect of BIP field on k of the HS has not been explored. Study of thermal conductivities (k: without BIP and kp: including BIP) vs temperature predicts pyroelectric behavior of HS. Both k and kp show crossover at a temperature Tp. The result shows that below Tp, kp < k due to negative thermal expansion coefficient (TEC). However, above Tp, kp > k. Above Tp, piezoelectric polarization dominates over spontaneous polarization due to positive TEC. This generates more lattice mismatch resulting in the significant contribution of BIP field to thermal conductivity. Thus, Tp can be considered as primary pyroelectric transition temperature of the material as above Tp thermal expansion takes place which is the reason for the secondary pyroelectric effect. It is found that below Tp, kp is decreased; thus enhancing TE efficiency. For x=0.1, 0.2 and 0.3; Tp are close to 200, 210 and 260 K, respectively. Thus, k of the HS can be modified as per requirement by tailoring the Al composition; making it suitable simultaneously for the design of high-temperature pyroelectric sensors and TE module for maximum power production.

Keywords: AlₓIn₁₋ₓN/GaN heterostructure, built in polarization, pyroelectric behavior, thermoelectric efficiency

Procedia PDF Downloads 121

Authors: L. Foudia, K. Haddadi, M. Reffas

Abstract:

First principles study of structural, elastic, electronic and optical properties of the monoclinic perovskite type ScRhO₃ has been reported using the pseudo-potential plane wave method within the local density approximation. The calculated lattice parameters, including the lattice constants and angle β, are in excellent agreement with the available experimental data, which proving the reliability of the chosen theoretical approach. Pressure dependence up to 20 GPa of the single crystal and polycrystalline elastic constants has been investigated in details using the strain-stress approach. The mechanical stability, ductility, average elastic wave velocity, Debye temperature and elastic anisotropy were also assessed. Electronic band structure and density of states (DOS) demonstrated its semiconducting nature showing a direct band gap of 1.38 eV. Furthermore, several optical properties, such as absorption coefficient, reflectivity, refractive index, dielectric function, optical conductivity and electron energy loss function, have been calculated for radiation up to 40 eV.

Keywords: ab-initio, perovskite, DFT, band gap

Procedia PDF Downloads 80

Authors: Azazhu Wassie

Abstract:

This study tried to analyze the impact of the hydrologic and hydraulic parameters (catchment area, rainfall intensity, and runoff coefficient) on the referenced study area. The study was conducted in June 2023. The Aremenie River Dam has 30 years of record, which is reasonably sufficient data. It is a matter of common experience that, due to the failure of an instrument or the absence of a gauged river, the rainfall record at quite a number of stations is incomplete. From the analysis, the 50-year return period design flood is 62.685 m³/s at 1.2 hr peak time. This implies that for this watershed, the peak flood rate per km² area of the watershed is about this value, which ensures that high rainfall in the area can generate a higher rate of runoff per km² of the generating catchment. The Aremenie Rivers carry a large amount of sediment along with water. These sediments are deposited in the reservoir upstream of the dam because of the reduction in velocity. Sediment reduces the available capacity of the reservoir with continuous sedimentation; the useful life of the reservoir goes on decreasing.

Keywords: dam design, peak flood, rainfall, reservoir capacity, runoff

Procedia PDF Downloads 33

Authors: Behdoukht Mall Amiri, Zohreh Gheydar

Abstract:

The thrust of the current study was to investigate the relationship among EFL learners' creativity (CR), emotional intelligence (EI), and self-efficacy (SE). To this end, a group of 120 male and female learners, between the ages of 19 and 35 studying BA in English Translation and MA in Teaching English at Islamic Azad University, Central Tehran were selected using convenient sampling and were given three questionnaires: Bar-On’s EQ-I questionnaire by Bar-On (1997), the General Self-Efficacy Scale questionnaire (SGSES) by Sherer et al. (1982), and a questionnaire of creativity (CR) by O'Neil, Abedi, and Spielberger (1992). Analysis of the results through Pearson Moment Correlation Coefficient showed that there was not a significant relationship between students’ CR and EI, and EI and SE. In addition, CR and SE were correlated significantly but negatively. Multiple regressions revealed that CR could significantly predict SE. Regarding the findings of the study, the obtained results may help EFL teachers, teacher trainers, materials developers, and educational policy makers to possess a broader perspective and heightened degree knowledge toward the TEFL practice and to take practical steps toward the attainments of the desired objectives of the profession.

Keywords: creativity, emotional intelligence, self-efficacy, learning

Procedia PDF Downloads 448

Authors: Ahmed Abdelghany, Bernard Uguen, Christophe Moy, Dominique Lemur

Abstract:

The Internet of Things (IoT) is developed to ensure monitoring and connectivity within different applications. Thus, it is critical to study the channel propagation characteristics in Low Power Wide Area Network (LPWAN), especially Long Range Wide Area Network (LoRaWAN). In this paper, an in-depth investigation of the reciprocity between the uplink and downlink Channel State Information (CSI) is done by performing an outdoor measurement campaign in the area of Campus Beaulieu in Rennes. At each different location, the CSI reciprocity is quantified using the Pearson Correlation Coefficient (PCC) which shows a very high linear correlation between the uplink and downlink CSI. This reciprocity feature could be utilized for the physical layer security between the node and the gateway. On the other hand, most of the CSI shapes from different locations are highly uncorrelated from each other. Hence, it can be anticipated that this could achieve significant localization gain by utilizing the frequency hopping in the LoRa systems by getting access to a wider band.

Keywords: IoT, LPWAN, LoRa, effective signal power, onsite measurement

Procedia PDF Downloads 162

Authors: Z. Hormozi Moghaddam, M. Mokhtari-Dizaji, M. Movahedin, M. E. Ravari

Abstract:

Mechanical index (MI) is used for quantifying acoustic cavitation and the relationship between acoustic pressure and the frequency. In this study, modeling of the MI was applied to provide treatment protocol and to understand the effective physical processes on reproducibility of stem cells. The acoustic pressure and MI equations are modeled and solved to estimate optimal MI for 28, 40, 150 kHz and 1 MHz frequencies. Radial and axial acoustic pressure distribution was extracted. To validate the results of the modeling, the acoustic pressure in the water and near field depth was measured by a piston hydrophone. Results of modeling and experiments show that the model is consistent well to experimental results with 0.91 and 0.90 correlation of coefficient (p<0.05) for 1 MHz and 40 kHz. Low intensity ultrasound with 0.40 MI is more effective on the proliferation rate of the spermatogonial stem cells during the seven days of culture, in contrast, high MI has a harmful effect on the spermatogonial stem cells. This model provides proper treatment planning in vitro and in vivo by estimating the cavitation phenomenon.

Keywords: ultrasound, mechanical index, modeling, stem cell

Procedia PDF Downloads 334

Authors: Azadeh Askari, Ali Nasery Mohamad Abadi

Abstract:

The present study was conducted to investigate the relationship between career anchors and job satisfaction with emphasis on the mediating role of person-job fit. 502 managers and supervisors of ten operational areas of a large energy Company were selected as a cluster sample appropriate to the volume. The instruments used in this study were Career Anchor Questionnaire, Job Satisfaction Questionnaire and Person-job fit Questionnaire. Pearson correlation coefficient was used to analyze the data and AMOS software was used to determine the effect of career anchor variables and person-job fit on job satisfaction. Anchors of service and dedication, pure challenge and security and stability increase the person-job fit among managers and also the person-job fit plays a mediating role in relation to the effect it has on job satisfaction through these anchors. In contrast, the anchors of independence and autonomy reduce the person-job fit. Considering the importance of positive organizational attitudes and in order to have an optimal fit between job and worker, it is better that in human resources processes such as hiring and employing, the career anchors of the person should be considered so that the person can have more job satisfaction; and thus bring higher productivity for themselves and the organization.

Keywords: career anchor, job satisfaction, person-job fit, energy company, managers

Procedia PDF Downloads 121

Authors: F. Amireche, I. Mokbel, J. Jose, B. F. Belaribi

Abstract:

The experimental vapour-liquid equilibria (VLE) at isothermal conditions and excess molar Gibbs energies GE are carried out for the three binary mixtures: 1, 2- dichloroethane + ethylene glycol dimethyl ether, + diethylene glycol dimethyl ether or + diethylene glycol diethyl ether, at ten temperatures ranging from 273 to 353.15 K. A good static device was employed for these measurements. The VLE data were reduced using the Redlich-Kister equation by taking into consideration the vapour pressure non-ideality in terms of the second molar virial coefficient. The experimental data were compared to the results predicted with the DISQUAC and Dortmund UNIFAC group contribution models for the total pressures P, the excess molar Gibbs energies GE and the excess molar enthalpies HE.

Keywords: Disquac model, Dortmund UNIFAC model, 1, 2- dichloroethane, excess molar Gibbs energies GE, polyethers, VLE

Procedia PDF Downloads 269

Authors: K. B. Rajasekarababu, J. Karthik, G. Vinayagamurthy

Abstract:

This paper is intended to explain the influence of major axis on aerodynamic characteristics of elliptical section. Many engineering applications such as off shore structures, bridge piers, civil structures and pipelines can be modelled as a circular cylinder but flow over complex bodies like, submarines, Elliptical wing, fuselage, missiles, and rotor blades, in which the parameters such as axis ratio can influence the flow characteristics of the wake and nature of separation. Influence of Major axis in Flow characteristics of elliptical sections are examined both experimentally and computationally in this study. For this research, four elliptical models with varying major axis [*AR=1, 4, 6, 10] are analysed. Experimental works have been conducted in a subsonic wind tunnel. Furthermore, flow characteristics on elliptical model are predicted from k-ε turbulence model using the commercial CFD packages by pressure based transient solver with Standard wall conditions.The analysis can be extended to estimation and comparison of Drag coefficient and Fatigue analysis of elliptical sections.

Keywords: elliptical section, major axis, aerodynamic characteristics, k-ε turbulence model

Procedia PDF Downloads 436

Authors: Harish Kumar Sharma

Abstract:

The influence of different levels of inulin as a fat replacer on the quality of ice cream was investigated. The physicochemical, rheological and textural properties of control ice cream and ice cream prepared with inulin in different proportions were determined and correlated to the different parameters using Pearson correlation and Principle Component Analysis (PCA). Based on the overall acepectability, ice cream with 4% inulin was found best and was selected for preparation of ice cream with inulin:SPI in different proportions. Compared with control ice cream, Inulin:SPI showed different rheological properties, resulting in significantly higher apparent viscosities, consistency coefficient and greater deviations from Newtonian flow. In addition, both hardness and melting resistance significantly increased with increase in the SPI content in ice cream prepared with inulin: SPI. Also hardness value increased for inulin based ice cream compared to control ice cream but it melted significantly faster than the latter. Colour value significantly decreased in both the cases compared to the control sample. The deliberation shall focus on the effect of incorporation of inulin on the quality of ice-cream.

Keywords: fat replacer, inulin, ice cream, viscosity, principal component analysis

Procedia PDF Downloads 384

Authors: Cristian P. Topa, Esteban A. Valencia, Victor H. Hidalgo, Marco A. Martinez

Abstract:

Wind tunnel experiments for aerodynamic profiles display numerous advantages, such as: clean steady laminar flow, controlled environmental conditions, streamlines visualization, and real data acquisition. However, the experiment instrumentation usually is expensive, and hence, each test implies a incremented in design cost. The aim of this work is to select and implement a low-cost static pressure data acquisition system for a NACA 2412 airfoil in an open cycle wind tunnel. This work compares wind tunnel experiment with Computational Fluid Dynamics (CFD) simulation and parametric analysis. The experiment was evaluated at Reynolds of 1.65 e⁵, with increasing angles from -5° to 15°. The comparison between the approaches show good enough accuracy, between the experiment and CFD, additional parametric analysis results differ widely from the other methods, which complies with the lack of accuracy of the lateral approach due its simplicity.

Keywords: wind tunnel, low cost instrumentation, experimental testing, CFD simulation

Procedia PDF Downloads 180

Authors: N. Chetty, K. Singh

Abstract:

In this work, the relationship between the melanin content in a tissue and subsequent absorption of light through that tissue was determined using a digital camera. This technique proved to be simple, cost effective, efficient and reliable. Tissue phantom samples were created using milk and soy sauce to simulate the optical properties of melanin content in human tissue. Increasing the concentration of soy sauce in the milk correlated to an increase in melanin content of an individual. Two methods were employed to measure the light transmitted through the sample. The first was direct measurement of the transmitted intensity using a conventional lux meter. The second method involved correctly calibrating an ordinary digital camera and using image analysis software to calculate the transmitted intensity through the phantom. The results from these methods were then graphically compared to the theoretical relationship between the intensity of transmitted light and the concentration of absorbers in the sample. Conclusions were then drawn about the effectiveness and efficiency of these low cost methods.

Keywords: tissue phantoms, scattering coefficient, albedo, low-cost method

Procedia PDF Downloads 271

Authors: Samuel Oluwafemi Oyamakin, Angela Unna Chukwu

Abstract:

Richrads growth equation being a generalized logistic growth equation was improved upon by introducing an allometric parameter using the hyperbolic sine function. The integral solution to this was called hyperbolic Richards growth model having transformed the solution from deterministic to a stochastic growth model. Its ability in model prediction was compared with the classical Richards growth model an approach which mimicked the natural variability of heights/diameter increment with respect to age and therefore provides a more realistic height/diameter predictions using the coefficient of determination (R2), Mean Absolute Error (MAE) and Mean Square Error (MSE) results. The Kolmogorov-Smirnov test and Shapiro-Wilk test was also used to test the behavior of the error term for possible violations. The mean function of top height/Dbh over age using the two models under study predicted closely the observed values of top height/Dbh in the hyperbolic Richards nonlinear growth models better than the classical Richards growth model.

Keywords: height, diameter at breast height, DBH, hyperbolic sine function, Pinus caribaea, Richards' growth model

Procedia PDF Downloads 392

Authors: Sungroul Kim, Yeonjin Kim

Abstract:

This study was conducted by comparing the concentrations of heavy metals analyzed from the same samples with three X-Ray fluorescence (XRF) spectrometer in three different global research institutions, including PAN (A Branch of Malvern Panalytical, Seoul, South Korea), RTI (Research Triangle Institute, NC, U.S.A), and aerosol laboratory in Harvard University, Boston, U.S.A. To achieve our research objectives, the indoor air filter samples were collected at homes (n=24) of adults or child asthmatics then analyzed in PAN followed by Harvard University and RTI consecutively. Descriptive statistics were conducted for data comparison as well as correlation and simple regression analysis using R version 4.0.3. As a result, detection rates of most heavy metals analyzed in three institutions were about 90%. Of the 25 elements commonly analyzed among those institutions, 16 elements showed an R² (coefficient of determination) of 0.7 or higher (10 components were 0.9 or higher). The findings of this study demonstrated that XRF was a useful device ensuring reproducibility and compatibility for measuring heavy metals in PM2.5 collected from indoor air of asthmatics’ home.

Keywords: heavy metals, indoor air quality, PM2.5, X-ray fluorescence

Procedia PDF Downloads 200

Authors: Talal Al-Bazali

Abstract:

Air drilling has recently received increasing acceptance by the oil and gas industry due to its unique advantages. The main advantages of air drilling include the higher rate of penetration, less formation damage, lower risk of loss of circulation. However, these advantages cannot be fully realized if thermal effects in air drilling are not well understood and minimized. Due to its high frictional coefficient, low heat conductivity, and high compressibility, air can impact the temperature distribution of bit and thus affect its bit performances. Based on energy and mass balances, a transient thermal model that predicts bit temperature is presented along with numerical solutions in this paper. In addition, several important parameters that influence bit temperature distribution are analyzed. Simulation results show that the bit temperature increases with increasing weight on bit and rotary speed but decreases as the standpipe pressure and flow rate increase. These results can be used to optimize drilling operations and flow parameters for an improved bit performance as shown in this paper.

Keywords: air drilling, rate of penetration, temperature, rotary speed

Procedia PDF Downloads 285

Authors: Monika Chuchro

Abstract:

This paper presents a preliminary attempt to apply classification of time series using meta-clusters in order to improve the quality of regression models. In this case, clustering was performed as a method to obtain a subgroups of time series data with normal distribution from inflow into waste water treatment plant data which Composed of several groups differing by mean value. Two simple algorithms: K-mean and EM were chosen as a clustering method. The rand index was used to measure the similarity. After simple meta-clustering, regression model was performed for each subgroups. The final model was a sum of subgroups models. The quality of obtained model was compared with the regression model made using the same explanatory variables but with no clustering of data. Results were compared by determination coefficient (R2), measure of prediction accuracy mean absolute percentage error (MAPE) and comparison on linear chart. Preliminary results allows to foresee the potential of the presented technique.

Keywords: clustering, data analysis, data mining, predictive models

Procedia PDF Downloads 466

Authors: Kazem Samadi

Abstract:

In today’s world, public agencies like customs have become vital institutions in international trade processes and in maintaining national economic security due to increasing economic and commercial complexities. In this regard, human resource management (HRM) is crucial to achieving organizational goals. This research employed a descriptive survey method, in which the statistical population consisted of all customs employees. Using Cochran's formula, 300 employees were selected from the central customs office. A researcher-made questionnaire was used as the data collection tool, with content validity and reliability confirmed using Cronbach's alpha coefficient. The collected data were analyzed through structural modeling using SPSS and AMOS 24. The results indicated that leadership culture significantly affected employee motivation, efficiency, and performance in customs. Customs managers and leaders in Iran can improve organizational productivity by fostering this culture, thereby facilitating individual and organizational development for their staff.

Keywords: leadership culture, organizational culture, employee performance, customs

Procedia PDF Downloads 19

Authors: Samar Aoujia, Théo Guérineaub, Rayan Zaitera, Evelyne Fargina, Younès Messaddeqb, Thierry Cardinala

Abstract:

Two barium gallo-germanate glass series were elaborated to investigate the effect of the yttrium introduction on the glass physicochemical properties and crystallization behavior. One to twenty mol% of YO3/2 were either added into the glass matrix or substituted for gallium oxide. The glass structure was studied by Raman spectroscopy, and the thermal, optical, thermo-mechanical and physical properties are examined. The introduction of yttrium ions in both glass series increases the glass transition temperature, crystallization temperature, softening temperature, coefficient of linear thermal expansion and density. Through differential scanning calorimetry and X-ray diffraction analyses, it was found that competition occurs between the gallo-germanate zeolite-type phase and the yttrium-containing phase. From 13 mol% of YO3/2, the yttrium introduction impedes the formation of surface crystallization in these glasses.

Keywords: photonic, heavy-metal oxide, glass, crystallization

Procedia PDF Downloads 144

Authors: N. Ouslimani, M. T. Abadlia, S. Yakoub, F. Tebbani

Abstract:

Water has always been synonymous with life and growth. Blue gold is first essential to the survival of the human being whose body consists of more than 65% with the development of industrialization and consumption patterns; volumes of wastewater discharges have increased considerably whether industrial or domestic, waste water must be purified before discharge. Treatment, therefore, aims to reduce the pollution load which contain. The resources in Algeria are limited and unevenly distributed. Thus, to meet all the water needs of the country and to preserve the waters of good quality drinking water supply, one solution would be to use them according to their quality and to irrigate crops for the food or be directed to the irrigation of green areas or sports complex. The purification performance of this STEP has been established since the pH analyzed pollution criteria (7.36) and temperature (16°C), MES (10 mg / l), electrical conductivity (1122 / µs / cm), DBO5 (6mg / l), DCO (15mg / l) meet the discharge standards. Arguably the purified water discharged out of the boumerdes STEP comply with Algerian regulations and can be reused in agriculture. COD biodegradability of the coefficient / BOD5 is 2.5 (less than 3) indicates that of the effluent are biodegradable hence their urban origin.

Keywords: irrigation, recovery, treated, wastewater

Procedia PDF Downloads 253

Authors: Rizwan Arshad, Alessio Panza, Nimra Inayat, Syeda Mariam Batool Kazmi, Shawana Azmat

Abstract:

The rapidly expanding use of immunotherapy for a wide range of cancers from late to early stages has, predictably, been accompanied by evidence of inequities in access to these highly effective but costly treatments. In this survey-based case study, we aimed to develop a One-window services model (OWSM) based on Anderson’s behavioral model to enhance competence in accessing cancer medications, particularly immunotherapies, through the analysis of 20 patient surveys conducted in the Armed forces bone marrow transplant center of the district, Rawalpindi from November to December 2022. The purposive sampling technique was used. Cronbach’s alpha coefficient was found to be 0.71. It was analyzed using SPSS version 26 with descriptive analysis, and results showed that the majority of the cancer patients were non-competent to access their prescribed cancer immunotherapy because of individual-level, socioeconomic, and organizational barriers.

Keywords: cancer immunotherapy, one-window services model, accessibility, competence

Procedia PDF Downloads 76

Authors: Mohamed S. Osman, Mohamed R. Nosair

Abstract:

The study aims to determine the effects of mindfulness on self-efficacy and professional success among educators of general and special education at Qatar Independent. The study sample will consist of 100 educators from the males and females divided to (50) educators of general education and (50) educators of Special Education in primary, and high schools. They will response to mindfulness scale and the scale of self-efficacy. In addition, use reports of the assessment by the Department of Education for their performance and assessments of their supervisors. The study will examine the effect of some variables such as differences between educators from general and special education, as well as the differences between males and females and years of experience. The study will use a statistic descriptive approach and Correlative analysis such as; means and the Pearson correlation coefficient. The study may predicts differences between educators in all variables study.

Keywords: mindfulness, educators, general education, special education, academic performance, self-efficacy

Procedia PDF Downloads 354

Authors: P. C. Okafor, A. J. Ekpunobi

Abstract:

Mn doped copper sulphide (CuS:Mn) nano-films were deposited on indiums coated tin oxide (ITO) glass substrates using electrodeposition method. Electrodeposition was carried out using bath of PH = 3 at room temperature. Other depositions parameters such as deposition time (DT) are kept constant while Mn doping was varied from 3% to 23%. Absorption spectra of CuS:Mn films was obtained by using JENWAY 6405 UV-VIS -spectrophotometer. Optical band gap (E_g ), optical conductivity (σo) and electrical conductivity (σe) of CuS:Mn films were determined using absorption spectra and appropriate formula. The effect of Mn doping % on these properties were investigated. Results show that film thickness (t) for the 13.27 nm to 18.49 nm; absorption coefficient (α) from 0.90 x 1011 to 1.50 x 1011 optical band gap from 2.29eV to 2.35 eV; optical conductivity from 1.70 x 1013 and electrical conductivity from 160 millions to 154 millions. Possible applications of such films for solar cells fabrication and optoelectronic devices applications were also discussed.

Keywords: copper sulphide (CuS), Manganese (Mn) doping, electrodeposition, optical band gap, optical conductivity, electrical conductivity

Procedia PDF Downloads 722

Authors: Yuyan Yi, Jingyi Zheng, Nedret Billor

Abstract:

Independent component analysis (ICA) is one of the most commonly used blind source separation (BSS) techniques for signal pre-processing, such as noise reduction and feature extraction. The main parameter in the ICA method is the number of independent components (IC). Although there have been several methods for the determination of the number of ICs, it has not been given sufficient attentionto this important parameter. In this study, wereview the mostused methods fordetermining the number of ICs and providetheir advantages and disadvantages. Further, wepropose an improved version of column-wise ICAByBlock method for the determination of the number of ICs.To assess the performance of the proposed method, we compare the column-wise ICAbyBlock with several existing methods through different ICA methods by using simulated and real signal data. Results show that the proposed column-wise ICAbyBlock is an effective and stable method for determining the optimal number of components in ICA. This method is simple, and results can be demonstrated intuitively with good visualizations.

Keywords: independent component analysis, optimal number, column-wise, correlation coefficient, cross-validation, ICAByblock

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Authors: Bharatendra Rai

Abstract:

Predictive data analysis and modeling involving machine learning techniques become challenging in presence of too many explanatory variables or features. Presence of too many features in machine learning is known to not only cause algorithms to slow down, but they can also lead to decrease in model prediction accuracy. This study involves housing dataset with 79 quantitative and qualitative features that describe various aspects people consider while buying a new house. Boruta algorithm that supports feature selection using a wrapper approach build around random forest is used in this study. This feature selection process leads to 49 confirmed features which are then used for developing predictive random forest models. The study also explores five different data partitioning ratios and their impact on model accuracy are captured using coefficient of determination (r-square) and root mean square error (rsme).

Keywords: housing data, feature selection, random forest, Boruta algorithm, root mean square error

Procedia PDF Downloads 323

Authors: Bushra Mussawar, Saleha Younus

Abstract:

Students often view their academic life demanding and stressful. However, apart from academics, stress springs from various other sources namely, finance, family, health, friends etc. The present study aims to assess the level of perceived stress in medical and fine arts students, and to determine the coping strategies used by the students to mitigate stress. The sample of the study consisted of 178 medical and fine arts students. The sample was selected through purposive sampling. Pearson correlation coefficient and T-test were used to analyze data. Results of the study revealed that there exists a positive relationship between perceived stress and coping strategies. Additionally, the two groups showed marked differences in terms of stress perception and coping styles. The level of perceived stress was found to be high in medical students nonetheless, they employed more positive coping strategies than fine arts students who scored high on negative coping strategies which are deleterious to the overall wellbeing.

Keywords: perceived stress, coping strategies, medical, fine arts students

Procedia PDF Downloads 307

Authors: Apolinar Picado, Ronald Solís, Rafael Gamero

Abstract:

The thin-layer drying characteristics of instant coffee solution were investigated in a laboratory tunnel dryer. Drying experiments were carried out at three temperatures (80, 100 and 120 °C) and an air velocity of 1.2 m/s. Drying experimental data obtained are fitted to six (6) thin-layer drying models using the non-linear least squares regression analysis. The acceptability of the thin-layer drying model has been based on a value of the correlation coefficient that should be close to one, and low values for root mean square error (RMSE) and chi-square (x²). According to this evaluation, the most suitable model for describing drying process of thin-layer instant coffee solution is the Page model. Further, the effective moisture diffusivity and the activation energy were computed employing the drying experimental data. The effective moisture diffusivity values varied from 1.6133 × 10⁻⁹ to 1.6224 × 10⁻⁹ m²/s over the temperature range studied and the activation energy was estimated to be 162.62 J/mol.

Keywords: activation energy, diffusivity, instant coffee, thin-layer models

Procedia PDF Downloads 262

Authors: L. Foudia, K. Haddadi, M. Reffas

Abstract:

First principles study of structural, elastic, electronic and optical properties of the monoclinic perovskite type ScRhO₃ has been reported using the pseudo-potential plane wave method within the local density approximation. The calculated lattice parameters, including the lattice constants and angle β are in excellent agreement with the available experimental data, which proving the reliability of the chosen theoretical approach. Pressure dependence up to 20 GPa of the single crystal and polycrystalline elastic constants has been investigated in details using the strain-stress approach. The mechanical stability, ductility, average elastic wave velocity, Debye temperature and elastic anisotropy were also assessed. Electronic band structure and density of states (DOS) demonstrated its semiconducting nature showing a direct band gap of 1.38 eV. Furthermore, several optical properties, such as absorption coefficient, reflectivity, refractive index, dielectric function, optical conductivity and electron energy loss function have been calculated for radiation up to 40 eV.

Keywords: ab-initio, perovskite, DFT, band gap.

Procedia PDF Downloads 74

Authors: Li Zhang, Yuehong Su

Abstract:

Lightpipe as a mature solar light tube technique has been employed worldwide. Accurately assessing the performance of lightpipe and evaluate daylighting available has been a challenging topic. Previous research had used regression model and computational simulation methods to estimate the performance of lightpipe. However, due to the nonlinear nature of solar light transferring in lightpipe, the methods mentioned above express inaccurate and time-costing issues. In the present study, a neural network model as an alternative method is investigated to predict the transmittance of lightpipe. Four types of commercial lightpipe with bended angle 0°, 30°, 45° and 60° are discussed under clear, intermediate and overcast sky conditions respectively. The neural network is generated in MATLAB by using the outcomes of an optical software Photopia simulations as targets for networks training and testing. The coefficient of determination (R²) for each model is higher than 0.98, and the mean square error (MSE) is less than 0.0019, which indicate the neural network strong predictive ability and the use of the neural network method could be an efficient technique for determining the performance of lightpipe.

Keywords: neural network, bended lightpipe, transmittance, Photopia

Procedia PDF Downloads 152

Authors: A. Maouassi, A. Beghidja, S. Daoud, N. Zeraibi

Abstract:

This paper illustrates a practical application of nanoparticles (TiO₂) as working fluid to stimulate solar flat plate collector efficiency with heat transfer modification properties. A numerical study of nanofluids laminar forced convection, permanent and stationary, is conducted in a solar flat plate collector. The effectiveness of these nanofluids are compared to conventional working fluid (water), wherein the dynamic and thermal properties are evaluated for four volume concentrations of nanoparticles (1%, 3%, 5% and 10%), and this done for Reynolds number from 25 to 800. Results from the application of those nonfluids are obtained versus pressure drop coefficient and Nusselt number are discussed later in this paper. Finally, we concluded that the heat transfer increases with increasing both nanoparticles concentration and Reynolds number.

Keywords: CFD, forced convection, nanofluid, solar flat plate collector efficiency, TiO₂ nanoparticles

Procedia PDF Downloads 160