Search results for: density functional theoretical

Authors: Yalong Jiang, Zheru Chi

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In this paper, we study the factors which determine the capacity of a Convolutional Neural Network (CNN) model and propose the ways to evaluate and adjust the capacity of a CNN model for best matching to a specific pattern recognition task. Firstly, a scheme is proposed to adjust the number of independent functional units within a CNN model to make it be better fitted to a task. Secondly, the number of independent functional units in the capsule network is adjusted to fit it to the training dataset. Thirdly, a method based on Bayesian GAN is proposed to enrich the variances in the current dataset to increase its complexity. Experimental results on the PASCAL VOC 2010 Person Part dataset and the MNIST dataset show that, in both conventional CNN models and capsule networks, the number of independent functional units is an important factor that determines the capacity of a network model. By adjusting the number of functional units, the capacity of a model can better match the complexity of a dataset.

Keywords: CNN, convolutional neural network, capsule network, capacity optimization, character recognition, data augmentation, semantic segmentation

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Authors: Pranav Gunhal., Krish Jhurani

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This study tackles the significant computational challenge of predicting excited state dynamics in organic photovoltaic (OPV) materials—a pivotal factor in the performance of solar energy solutions. Time-dependent density functional theory (TDDFT), though effective, is computationally prohibitive for larger and more complex molecules. As a solution, the research explores the application of transformer neural networks, a type of artificial intelligence (AI) model known for its superior performance in natural language processing, to predict excited state dynamics in OPV materials. The methodology involves a two-fold process. First, the transformer model is trained on an extensive dataset comprising over 10,000 TDDFT calculations of excited state dynamics from a diverse set of OPV materials. Each training example includes a molecular structure and the corresponding TDDFT-calculated excited state lifetimes and key electronic transitions. Second, the trained model is tested on a separate set of molecules, and its predictions are rigorously compared to independent TDDFT calculations. The results indicate a remarkable degree of predictive accuracy. Specifically, for a test set of 1,000 OPV materials, the transformer model predicted excited state lifetimes with a mean absolute error of 0.15 picoseconds, a negligible deviation from TDDFT-calculated values. The model also correctly identified key electronic transitions contributing to the excited state dynamics in 92% of the test cases, signifying a substantial concordance with the results obtained via conventional quantum chemistry calculations. The practical integration of the transformer model with existing quantum chemistry software was also realized, demonstrating its potential as a powerful tool in the arsenal of materials scientists and chemists. The implementation of this AI model is estimated to reduce the computational cost of predicting excited state dynamics by two orders of magnitude compared to conventional TDDFT calculations. The successful utilization of transformer neural networks to accurately predict excited state dynamics provides an efficient computational pathway for the accelerated discovery and design of new OPV materials, potentially catalyzing advancements in the realm of sustainable energy solutions.

Keywords: transformer neural networks, organic photovoltaic materials, excited state dynamics, time-dependent density functional theory, predictive modeling

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Authors: Luv Sharma

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Sex determination has been the most intriguing puzzle for forensic pathologists and anthropologists, for which efforts have been made for a long. Sexual dimorphism is well established in the adult pelvis, and it is known to provide the highest level of information about sexual dimorphism. This study was conducted to know whether this dimorphism exists in fetal bones or not. A total of 34 pairs of fetal pelvis bones (22 males and 12 Females), ages ranging from 4 months to full term, were collected from unidentified dead fetuses brought to the Department of Forensic Medicine for routine medicolegal autopsies to study for sexual dimorphism in the Department of Anatomy, Pt. BD Sharma PGIMS, Rohtak. Samples were divided into 2 age groups, and various metric parameters were recorded with the help of a digital vernier caliper. Data obtained was subjected to descriptive and discriminant functional analysis. Results of Descriptive and Discriminant Functional Analysis showed that sex determination can be done with 100% accuracy by using different combinations of parameters of fetal ilium. This study illustrates that sexual dimorphism exists from early fetal life after mid-pregnancy; it can be clearly established by discriminant functional analysis.

Keywords: Ilium, fetus, sex determination, morphometric

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Authors: Lotanna Ezeonu, Jason P. Robbins, Ziyu Tang, Xiaofang Yang, Bruce E. Koel, Simon G. Podkolzin

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The interaction of organic molecules with metal surfaces is of interest in numerous technological applications, such as catalysis, bone replacement, and biosensors. Acetic acid is one of the main products of bio-oils produced from the pyrolysis of hemicellulosic feedstocks. However, their high oxygen content makes them unsuitable for use as fuels. Hydrodeoxygenation is a proven technique for catalytic deoxygenation of bio-oils. An understanding of the energetics and control of the bond-breaking sequences of biomass-derived oxygenates on metal surfaces will enable a guided optimization of existing catalysts and the development of more active/selective processes for biomass transformations to fuels. Such investigations have been carried out with the aid of ultrahigh vacuum and its concomitant techniques. The high catalytic activity of platinum in biomass-derived oxygenate transformations has sparked a lot of interest. We herein exploit infrared reflection absorption spectroscopy(IRAS), temperature-programmed desorption(TPD), and density functional theory(DFT) to study the adsorption and decomposition of acetic acid on a Pt(111) surface, which was then compared with Ni(111), a model non-noble metal. We found that acetic acid adsorbs molecularly on the Pt(111) surface, interacting through the lone pair of electrons of one oxygen atomat 90 K. At 140 K, the molecular form is still predominant, with some dissociative adsorption (in the form of acetate and hydrogen). Annealing to 193 K led to complete dehydrogenation of molecular acetic acid species leaving adsorbed acetate. At 440 K, decomposition of the acetate species occurs via decarbonylation and decarboxylation as evidenced by desorption peaks for H₂,CO, CO₂ and CHX fragments (x=1, 2) in theTPD.The assignments for the experimental IR peaks were made using visualization of the DFT-calculated vibrational modes. The results showed that acetate adsorbs in a bridged bidentate (μ²η²(O,O)) configuration. The coexistence of linear and bridge bonded CO was also predicted by the DFT results. Similar molecular acid adsorption energy was predicted in the case of Ni(111) whereas a significant difference was found for acetate adsorption.

Keywords: acetic acid, platinum, nickel, infared-absorption spectrocopy, temperature programmed desorption, density functional theory

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Authors: Shokouh Momeni, Mohammad Reza Salamat, Ali Asghar Rastegari

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Background: Osteoporosis is the most prevalent metabolic bone disease in postmenopausal women associated with reduced bone mass and increased bone fracture. Measuring bone density in the lumbar spine and hip is a reliable measure of bone mass and can therefore specify the risk of fracture. Dual-energy X-ray absorptiometry(DXA) is an accurate non-invasive system measuring the bone density, with low margin of error and no complications. The present study aimed to investigate the relationship between biochemical parameters with bone density in postmenopausal women. Materials and methods: This cross-sectional study was conducted on 87 postmenopausal women referred to osteoporosis centers in Isfahan. Bone density was measured in the spine and hip area using DXA system. Serum levels of calcium, phosphorus, alkaline phosphatase and magnesium were measured by autoanalyzer and serum levels of vitamin D were measured by high-performance liquid chromatography(HPLC). Results: The mean parameters of calcium, phosphorus, alkaline phosphatase, vitamin D and magnesium did not show a significant difference between the two groups(P-value>0.05). In the control group, the relationship between alkaline phosphatase and BMC and BA in the spine was significant with a correlation coefficient of -0.402 and 0.258, respectively(P-value<0.05) and BMD and T-score in the femoral neck area showed a direct and significant relationship with phosphorus(Correlation=0.368; P-value=0.038). There was a significant relationship between the Z-score with calcium(Correlation=0.358; P-value=0.044). Conclusion: There was no significant relationship between the values ​​of calcium, phosphorus, alkaline phosphatase, vitamin D and magnesium parameters and bone density (spine and hip) in postmenopaus

Keywords: osteoporosis, menopause, bone mineral density, vitamin d, calcium, magnesium, alkaline phosphatase, phosphorus

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Authors: Rayenne Djemil

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The mechanism of oxidation reaction of linoleic acid C18: 2 (9 cis12) by singlet oxygen 1O2 were theoretically investigated via using quantum chemical methods. We explored the four reaction pathways at PM3, Hartree-Fock HF and, B3LYP functional associated with the base 6-31G (d) level. The results are in favor of the first and the last reaction ways. The transition states were found by QST3 method. Thus the pathways between the transition state structures and their corresponding minima have been identified by the IRC calculations. The thermodynamic study showed that the four ways of oxidation of linoleic acid are spontaneous, exothermic and, the enthalpy values confirm that conjugate hydroperoxydes are the most favorable products.

Keywords: echanism, quantum mechanics, oxidation, linoleic acid H

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Authors: Benson Ade Eniola Afere

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Over the years, kernel density estimation has been extensively studied within the context of nonparametric density estimation. The fundamental components of kernel density estimation are the kernel function and the bandwidth. While the mathematical exploration of the kernel component has been relatively limited, its selection and development remain crucial. The Mean Integrated Squared Error (MISE), serving as a measure of discrepancy, provides a robust framework for assessing the effectiveness of any kernel function. A kernel function with a lower MISE is generally considered to perform better than one with a higher MISE. Hence, the primary aim of this article is to create kernels that exhibit significantly reduced MISE when compared to existing classical kernels. Consequently, this article introduces a cluster of hybrid polynomial kernel families. The construction of these proposed kernel functions is carried out heuristically by combining two kernels from the classical polynomial kernel family using probability axioms. We delve into the analysis of error propagation within these kernels. To assess their performance, simulation experiments, and real-life datasets are employed. The obtained results demonstrate that the proposed hybrid kernels surpass their classical kernel counterparts in terms of performance.

Keywords: classical polynomial kernels, cluster of families, global error, hybrid Kernels, Kernel density estimation, Monte Carlo simulation

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Authors: Maher J. Tadros, Yaseen Ananbeh

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The study area is located in Ajluon Forest Reserve northern part of Jordan. It consists of Mediterranean hills dominated by open woodlands of oak and pistachio. The aims of the study were to investigate the positive and negative relationships between the locals and the protected area and how it can affect the long-term forest conservation. The main research objectives are to review the impact of establishing Ajloun Forest Reserve on nature conservation and on the livelihood level of local communities around the reserve. The Ajloun forest reserve plays a fundamental role in Ajloun area development. The existence of initiatives of nature conservation in the area supports various socio-economic activities around the reserve that contribute towards the development of local communities in Ajloun area. A part of this research was to conduct a survey to study the impact of Ajloun forest reserve on biodiversity composition. Also, studying the biodiversity content especially for vegetation to determine the economic impacts of Ajloun forest reserve on its surroundings was studied. In this study, several methods were used to fill the objectives including point-centered quarter method which involves selecting randomly 50 plots at the study site. The collected data from the field showed that the absolute density was (1031.24 plant per hectare). Density was recorded and found to be the highest for Quecus coccifera, and relative density of (73.7%), this was followed by Arbutus andrachne and relative density (7.1%), Pistacia palaestina and relative density (10.5%) and Crataegus azarulus (82.5 p/ha) and relative density (5.1%),

Keywords: composition, density, frequency, importance value, point-centered quarter, structure, tree cover

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Authors: T. S. Olugbemi, T. S. Friday, O. O. Olusola

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This experiment was carried out to assess the effect of different stocking densities and vitamin C supplementation on the performance of Japanese quails. Five hundred and twenty (520) unsexed quail birds of two (2) weeks of age were allotted randomly into nine (9) groups with 3 replicates each in a 3x3 factorial arrangement (3 stocking density levels and 3 graded vitamin C levels) with densities of 150, 120, 90 cm2/bird(11, 16, 21 birds). During the five weeks growing trial (2- 6 weeks), results showed that stocking density had significant effects on final weight (131.59g compared to 111.10g for the lowest), total and daily weight gain. No significance difference was observed for feed conversion ratio, age at first lay and first egg weight. Observations on haematological parameters (packed cell volume (PCV), total protein (TP), haemoglobin, red blood cell (RBC), lymphocyte, heterophil) on stocking density showed no significant differences. Vitamin C supplementation at 50mg/kg and 100mg/kg did not have any significant effect on the growth performance parameters of growing quails. Stocking density at 150cm2/bird had a better performance with or without vitamin C supplementation hence it is recommended that stocking rates of quails between the ages of 2 – 6 weeks should not be below 150cm2/bird.

Keywords: anti-oxidants, performance, stress, stocking density

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Authors: Jiwuer Jilili, Ulrich Eckern, Udo Schwingenschlogl

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We present first principles results for the electronic, magnetic, and optical properties of the BiFeO3 /La2/3Sr1/3MnO3 heterostructure as obtained by spin polarized calculations using density functional theory. The electronic states of the heterostructure are compared to those of the bulk compounds. Structural relaxation turns out to have only a minor impact on the chemical bonding, even though the oxygen octahedra in La2/3Sr1/3MnO3 develop some distortions due to the interface strain. While a small charge transfer affects the heterointerfaces, our results demonstrate that the half-metallic character of La2/3Sr1/3MnO3 is fully maintained.

Keywords: BiFeO3, La2/3Sr1/3MnO3, superlattice, half-metallicity

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Authors: Oluwafemi Babatunde Oduntan, Isaac A. Bamgboye

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The solid waste disposal and its management from pineapple juice processing constitute environmental contamination affecting public health. The use of this by-product called pomace has potentials to reduce cost of aquafeed. Pineapple pomace collected after juice extraction was dried and milled. The interactive effects of feeding rate (1.28, 1.44 and 1.60kg/min), screw speed (305, 355 and 405rpm), moisture content (16, 19 and 22%), temperatures (60, 80, 100 and 120°C), cutting speed (1300, 1400 and 1500rpm), pomace inclusion ratio (5, 10, 15, 20%) and open surface die (50, 75 and 100%) on the extrudate physical properties (bulk density, unit density, expansion ratio, durability and floatability) were investigated using optimal custom design (OCD) matrix and response surface methodology. The predicted values were found to be in good agreement with the experimental values for, expansion ratio, durability and floatability (R2 = 0.7970; 0.9264; 0.9098 respectively) with the exceptions of unit density and bulk density (R2 = 0.1639; 0.2768 respectively). All the extrudates showed relatively high floatability, durability. The inclusion of pineapple pomace produced less expanded and more compact textured extrudates. Results indicated that increased in the value of pineapple pomace, screw speed, feeding rate decreased unit density, bulk density, expansion ratio, durability and floatability of the extrudate. However, increasing moisture content of feed mash resulted in increase unit density and bulk density. Addition of extrusion temperature and cutting speed increased the floatability and durability of extrudate. The proportion of pineapple pomace in aquafeed extruded product was observed to have significantly lower effect on the selected responses.

Keywords: aquafeed, extrusion, physical properties, pineapple pomace, waste

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Authors: Milenko Košutić, Jelena Filipović, Zvonko Nježić

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Extrusion technology is thermal processing that is applied to improve the nutritional, hygienic, and physical-chemical characteristics of the raw material. Overall, the extrusion process is an efficient method for the production of a wide range of food products. It combines heat, pressure, and shear to transform raw materials into finished goods with desired textures, shapes, and nutritional profiles. The extruded products’ quality is remarkably dependent upon feed material composition, barrel temperature profile, feed moisture content, screw speed, and other extrusion system parameters. Given consumer expectations for snack foods, a high expansion index and low bulk density, in addition to crunchy texture and uniform microstructure, are desired. This paper investigates the effects of simultaneous different types of corn (white corn, yellow corn, red corn, and black corn) addition and different screw speed (350, 500, 650 rpm) on the physical, technological, and functional properties of flakes products. Black corn flour and screw speed at 350 rpm positively influenced physical, technological characteristics, mineral composition, and antioxidant properties of flake products with the best total score analysis of 0,59. Overall, the combination of Tukey's HSD test and PCA enables a comprehensive analysis of the observed corn products, allowing researchers to identify them. This research aims to analyze the influence of different types of corn flour (white corn, yellow corn, red corn, and black corn) on the nutritive and sensory properties of the product (quality, texture, and color), as well as the acceptance of the new product by consumers on the territory of Novi Sad. The presented data point that investigated corn flakes from black corn flour at 350 rpm is a product with good physical-technological and functional properties due to a higher level of antioxidant activity.

Keywords: corn types, flakes product, nutritive quality, acceptability

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Authors: Shu-Ching Chen, Li-Yun Lee

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The purpose of the study was to identify the factors associated with head and neck cancer-related lymphoedema (HNCRL)-related symptoms, body image, and HNCRL-related functional outcomes among patients with resected advanced head and neck cancer. A cross-sectional correlational design was conducted to examine the predictors of HNCRL-related functional outcomes in patients with resected advanced head and neck cancer. Eligible patients were recruited from a single medical center in northern Taiwan. Consecutive patients were approached and recruited from the Radiation Head and Neck Outpatient Department of this medical center. Eligible subjects were assessed for the Symptom Distress Scale–Modified for Head and Neck Cancer (SDS-mhnc), Brief International Classification of Functioning, Disability and Health (ICF) Core Set for Head and Neck Cancer (BCSQ-H&N), Body Image Scale–Modified (BIS-m), The MD Anderson Head and Neck Lymphedema Rating Scale (MDAHNLRS), The Foldi’s Stages of Lymphedema (Foldi’s Scale), Patterson’s Scale, UCLA Shoulder Rating Scale (UCLA SRS), and Karnofsky’s Performance Status Index (KPS). The results showed that the worst problems with body HNCRL functional outcomes. Patients’ HNCRL symptom distress and performance status are robust predictors across over for overall HNCRL functional outcomes, problems with body HNCRL functional outcomes, and activity and social functioning HNCRL functional outcomes. Based on the results of this period research program, we will develop a Cancer Rehabilitation and Lymphedema Care Program (CRLCP) to use in the care of patients with resected advanced head and neck cancer.

Keywords: head and neck cancer, resected, lymphedema, symptom, body image, functional outcome

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Authors: Kobus-Cisowska Joanna, Flaczyk Ewa, Gramza-Michalowska Anna, Kmiecik Dominik, Przeor Monika, Marcinkowska Agata, Korczak Józef

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The object of this study was to develop recipes and technology of production of functional bread with morus alba fruit addition. There were prepared four samples of functional breads and the control sample also. Bread recipe was designed for supporting the treatment of anemia, diabetes, obesity and cardiovascular diseases. Samples of bread were baked with mixes directly after preparation and after three months' storage, each time preparing the water and methanol extracts. The sensory analysis and nutritional value were estimated. The antioxidant activity were estimated used tests such as the ability to scavenge free radical DPPH, the ability to scavenge the ABTS cation, chelating properties and the total content of polyphenols. The study results showed that the prepared sample of functional breads were characterized by a high nutritional value with high concentration of biologically active compounds which showed antioxidant activity. In addition, the profile sensory of bread samples was highly rated. However, to determine whether they can be considered as a new product preset pro-health properties require additional nutritional studies - clinical trials.

Keywords: functional food, breads, white mulberry, bioactive components

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Authors: A. Boursali, A. Guen-Bouazza

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We present a simulation of a HEMT (high electron mobility transistor) structure with and without a field plate. We extract the device characteristics through the analysis of DC, AC and high frequency regimes, as shown in this paper. This work demonstrates the optimal device with a gate length of 15 nm, InAlN/GaN heterostructure and field plate structure, making it superior to modern HEMTs when compared with otherwise equivalent devices. This improves the ability to bear the burden of the current density passes in the channel. We have demonstrated an excellent current density, as high as 2.05 A/m, a peak extrinsic transconductance of 0.59S/m at VDS=2 V, and cutting frequency cutoffs of 638 GHz in the first HEMT and 463 GHz for Field plate HEMT., maximum frequency of 1.7 THz, maximum efficiency of 73%, maximum breakdown voltage of 400 V, leakage current density IFuite=1 x 10-26 A, DIBL=33.52 mV/V and an ON/OFF current density ratio higher than 1 x 1010. These values were determined through the simulation by deriving genetic and Monte Carlo algorithms that optimize the design and the future of this technology.

Keywords: HEMT, silvaco, field plate, genetic algorithm, quantum

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Authors: Sreejani Barua, P. P. Srivastav

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Formulation of new functional food products for diabetes patients and obsessed people is a challenge for food industries till date. Starch is a certainly happening, ecological, reasonable and profusely obtainable polysaccharide in plant material. In the present scenario, there is a great interest in modifying starch functional properties without destroying its granular structure using different modification techniques. Resistant starch (RS) contains almost zero calories and can control blood glucose level to prevent diabetes. The current study focused on modification of mung bean starch which is a good source of legumes carbohydrate for the production of functional food. Heat moisture treatment (HMT) of mung starch was conducted at moisture content of 10-30%, temperature of 80-120 °C and time of 8-24 h.The content of resistant starch after modification was significantly increased from native starches containing RS 7.6%. The design combinations of HMT had been completed through Central Composite Rotatable Design (CCRD). The effects of HMT process variables on the yield of resistant starch was studied through Rapid Surface Methodology (RSM). The highest increase of resistant starch was found up to 34.39% when treated the native starch with 30% m.c at 120 °C temperature for 24 h.The functional properties of both native and modified mung bean starches showed that there was a reduction in the swelling power and swelling volume of HMT starches. However, the solubility of the HMT starches was higher than that of untreated native starch and also observed change in structural (scanning electron microscopy), X-Ray diffraction (XRD) pattern, blue value and thermal (differential scanning calorimetry) properties. Therefore, replacing native mung bean starch with heat-moisture treated mung bean starch leads to the development of new products with higher resistant starch levels and functional properties.

Keywords: Mung bean starch, heat moisture treatment, functional properties, resistant starch

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Authors: Li Guoyou, Zhang Tao, Ji Wenzhan, Huo Liang, Lin Xiqiang, Zhang Nan

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The three dimensional (3D) printing technology has undergone rapid development in the last few years and it is possible to print engineering structures. 3D printing buildings use wastes from constructions, industries and mine tailings as “ink”, and mix it with property improved materials, such as cement, fiber etc. This paper presents a study of the Thermodynamic performance of 3D printed walls using cement and steel slag powder. Analyses the thermal simulation regarding 3D printed walls and solid brick wall by the way of the hot-box methods and the infrared technology, and the results were contrasted with theoretical calculation. The results show that the excellent thermodynamic performance of 3D printed concrete wall made it suitable as the partial materials for self-thermal insulation walls in residential buildings. The thermodynamic performance of 3D printed concrete walls depended on the density of materials, distribution of holes, and the filling materials. Decreasing the density of materials, increasing the number of holes or replacing the filling materials with foamed concrete could improve its thermodynamic performance significantly. The average of heat transfer coefficient and thermal inertia index of 3D printed steel slag powder concrete wall all better than the traditional solid brick wall with a thickness of 240mm.

Keywords: concrete, 3D printed walls, thermodynamic performance, steel slag powder

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Authors: Sirapat Lookrak, Anol Paisal

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Space debris has numerous manifestations, including ferro-metalize and non-ferrous. The electric field will induce negative charges to split from positive charges inside the space debris. In this research, we focus only on conducting materials. The assumption is that the electric charge density of a conducting surface is proportional to the electric field on that surface due to Gauss's Law. We are trying to find the induced charge density from an external electric field perpendicular to a conducting spherical surface. An object is a sphere on which the external electric field is not uniform. The electric field is, therefore, considered locally. The localised spherical surface is a tangent plane, so the Gaussian surface is a very small cylinder, and every point on a spherical surface has its own cylinder. The electric field from a circular electrode has been calculated in near-field and far-field approximation and shown Explanation Touchless maneuvering space debris orbit properties. The electric charge density calculation from a near-field and far-field approximation is done.

Keywords: near-field approximation, far-field approximation, localized Gauss’s law, electric charge density

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Authors: Monique Joyce L. Disamburum, Nicole C. Faustino, Ashley Angela A. Fazon, Jessie F. Rubonal

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Traditional jeepneys contribute significantly to air pollution in the Philippines, negatively affecting both the environment and people. In response, the researchers investigated Sphagnum moss which has high adsorbent properties and can be used as a filter. Therefore, this research aims to create a muffler filter additive to reduce the smoke density emitted by traditional jeepneys. Various materials, such as moss, cornstarch, a metal pipe, bolts, and a papermaking screen frame, were gathered. The moss underwent a blending process with a cornstarch mixture until it achieved a pulp-like consistency, subsequently molded using a papermaking screen frame and left for sun drying. Following this, a metal prototype was created by drilling holes around the tumbler and inserting bolts. The mesh wire containing the filter was carefully placed into the hole, secured by two bolts. In the final phase, there were three setups, each undergoing one trial in the LTO emission testing. Each trial consisted of six rounds of purging, and after that the average smoke density was measured. According to the findings of this study, the filter aided in lowering the average smoke density. The one layer setup produced an average of 1.521, whereas the two layer setup produced an average of 1.082. Using One-Way Anova, it was demonstrated that there is a significant difference between the setups. Furthermore, the Tukey HSD Post Hoc test revealed that Setups A and C differed significantly (p = 0.04604), with Setup C being the most successful in reducing smoke density (mean difference -1.4128). Overall, the researchers came to the conclusion that employing Sphagnum moss as a filter can lower the average smoke density released by traditional jeepneys.

Keywords: sphagnum moss, Jeepney filter, smoke density, Jeepney emission

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Authors: Jiajia Yao, Guanlin Wu, Fang Liu, Junshuai Xue, Yue Hao

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As the production process of self-standing GaN substrates evolves, the commercialization of low dislocation density, large-scale, semi-insulating self-standing GaN substrates is gradually becoming a reality. This advancement has given rise to increased interest in GaN materials' homoepitaxial technology. However, at the homoepitaxial interface, there are considerable concentrations of impurity elements, including C, Si, and O, which generate parasitic leakage channels at the re-growth junction. This phenomenon results in leaked HEMTs that prove difficult to switch off, rendering them effectively non-functional. The emergence of leakage channels can also degrade the high-frequency properties and lower the power devices' breakdown voltage. In this study, the uniform epitaxy of AlGaN/GaN heterojunction with high electron mobility was accomplished through the surface treatment of the GaN substrates prior to growth and the design of the AlN isolation layer structure. By employing a procedure combining gallium atom in-situ cleaning and plasma nitridation, the C and O impurity concentrations at the homoepitaxial interface were diminished to the scale of 10¹⁷ cm-³. Additionally, the 1.5 nm nitrogen-rich AlN isolation layer successfully prevented the diffusion of Si impurities into the GaN channel layer. The result was an AlGaN/GaN heterojunction with an electron mobility of 1552 cm²/Vs and an electron density of 1.1 × 10¹³ cm-² at room temperature, obtained on a Fe-doped semi-insulating GaN substrate.

Keywords: MBE, AlGaN/GaN, homogenerous epitaxy, HEMT

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Authors: A. Iqbal Banauaji, Muchamad Sholikun

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Diabetes mellitus (DM) is a metabolism disorder that tends to increase its prevalence in the world, including in Indonesia. The development of DM type 2 can cause oxidative stress characterized by an imbalance between oxidants and antioxidants in the body Increased oxidative stress causes type 2 diabetes mellitus to require intake of exogenous antioxidants in large quantities to inhibit oxidative damage in the body. Bran can be defined as a functional food because it consists of 11.39% fiberand 28.7% antioxidants and the purple yam consists of anthocyanin which functions as an antioxidant. With abundant amount and low price, purple yam and bran can be used for analog rice as the effort to diversify functional food. The antioxidant’s activity of analog rice from purple yam and bran which is measured by using DPPH’s method is 12,963%. The rough fiber’s level on the analog rice from purple yam is 2.985%. The water amount of analog rice from purple yam and bran is 8.726%. Analog rice from purple yam and bran has the similar texture as the usual rice, tasted slightly sweet, light purple colored, and smelled like bran.

Keywords: antioxidant, analog rice, functional food, diabetes mellitus

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Authors: Mao-Sheng Su, Santhanamoorthi Nachimuthu, Jyh-Chiang Jiang

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Climate change is widely recognized as a global crisis, with anthropogenic CO₂ emissions from fossil fuel combustion and industrial processes being major contributors. To address this challenge, carbon capture and sequestration (CCS) technology has emerged as a key strategy for selectively capturing CO₂ from flue gas streams. Among the various solid adsorbents, metal–organic frameworks (MOFs) are notable for their extensive surface area and controllable pore chemistry. The porous MOF structure is comprised of metal ions or clusters coordinated to organic linker compounds. In particular, the pore parameters of MOFs are readily tunable, making them promising materials for CO₂ capture applications. Among these, amine-functionalized MOFs have demonstrated exceptional CO₂ capture abilities because their high uptake capacity and selectivity. In this study, we have investigated the CO₂ capture abilities and adsorption mechanisms of the diamine-appended framework N-Ethylethylenediamine-Mg₂(4,4’-dioxidobiphenyl-3,3’-dicarboxylate) (e-2-Mg₂(dobpdc)) using density functional theory (DFT) calculations. Previous studies have suggested that CO₂ can be captured via both outer- and inner-amine binding sites. Our findings reveal that CO₂ adsorption at the outer amine site is kinetically more favorable compared to the inner amine site, with a lower energy barrier of 1.34 eV for CO₂ physisorption to chemisorption compared to the inner amine, which has an activation barrier of 1.60 eV. Furthermore, we find that CO₂ adsorption is significantly enhanced in an alkaline environment, as deprotonation of the diamine molecule reduces the energy barrier to 0.24 eV. This theoretical study provides detailed insights into CO₂ adsorption in diamine-appended e-2-Mg₂(dobpdc) MOF, offering a deeper understanding of CO₂ capture mechanisms and valuable information for the advancement of effective CO₂ sequestration technologies.

Keywords: DFT, MOFs, CO₂ capture, catalyst

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Authors: R. Shrestha, D. P. Subedi, R. B. Tyata, C. S. Wong,

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In this paper, a technique for the determination of electron temperatures and electron densities in atmospheric pressure Argon/air discharge by the analysis of optical emission spectra (OES) is reported. The discharge was produced using a high voltage (0-20) kV power supply operating at a frequency of 27 kHz in parallel electrode system, with glass as dielectric. The dielectric layers covering the electrodes act as current limiters and prevent the transition to an arc discharge. Optical emission spectra in the range of (300nm-850nm) were recorded for the discharge with different inter electrode gap keeping electric field constant. Electron temperature (Te) and electron density (ne) are estimated from electrical and optical methods. Electron density was calculated using power balance method. The optical methods are related with line intensity ratio from the relative intensities of Ar-I and Ar-II lines in Argon plasma. The electron density calculated by using line intensity ratio method was compared with the electron density calculated by stark broadening method. The effect of dielectric thickness on plasma parameters (Te and ne) have also been studied and found that Te and ne increases as thickness of dielectric decrease for same inter electrode distance and applied voltage.

Keywords: electron density, electron temperature, optical emission spectra,

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Authors: Sunitha Thappa

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Business environment is a set of complex interdependent dimensions that corporates have to always be vigil in identifying the influential waves. Over the year business environment has evolved into a basket of uncertainties. Every organization strives to counter this dynamic nature of business environment by recurrently evaluating the primary and support activities of its value chain. This has led to companies redesigning their business models, reinvent business processes and operating procedure on unremitting basis. A few specific issues that are placed before the present day managers are breaking down the functional interpretation of any challenge that organizations confronts, reduction in organizational hierarchy and tackling the components of the value chain to retain their competitive advantage. It is how effectively managers detect the changes and swiftly reorient themselves to these changes that define their success or failure. Given the complexity of decision making in this dynamic environment, two important question placed before the B-schools of today. Firstly, are they grooming and nurturing managerial talent proficient enough to thrive in this multifaceted business environment? Secondly, are the management graduates walking through their portals, able to view challenges from a cross-functional perspective with emphasis to customer and process rather than hierarchy and functions. This paper focuses on the need for a process oriented approach to management education.

Keywords: management education, pedagogy, functional, process

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Authors: Atif Naim, Faisal E. Ahmed, Sershen

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A field experiment was conducted for two consecutive winter seasons at the Demonstration Farm of the Faculty of Agriculture, University of Khartoum, Sudan, to study effects of different levels of irrigation regime and plant density on yield of introduced small seeded (desi type) chickpea cultivar (ILC 482). The experiment was laid out in a 3X3 factorial split-plot design with 4 replications. The treatments consisted of three irrigation regimes (designated as follows: I1 = optimum irrigation, I2 = moderate stress and I3 = severe stress; this corresponded with irrigation after drainage of 50%, 75% and 100% of available water based on 70%, 60% and 50% of field capacity, respectively) assigned as main plots and three plant densities (D₁=20, D₂= 40 and D₃= 60 plants/m²) assigned as subplots. The results indicated that the yield components (number of pods per plant, number of seeds per pod, 100 seed weight), seed yield per plant, harvest index and yield per unit area of chickpea were significantly (p < 0.05) affected by irrigation regime. Decreasing irrigation regime significantly (p < 0.05) decreased all measured parameters. Alternatively, increasing plant density significantly (p < 0.05) decreased the number of pods and seed yield per plant and increased seed yield per unit area. While number of seeds per pod and harvest index were not significantly (p > 0.05) affected by plant density. Interaction between irrigation regime and plant density was also significantly (p < 0.05) affected all measured parameters of yield, except for harvest index. It could be concluded that the best irrigation regime was full irrigation (after drainage of 50% available water at 70% field capacity) and the optimal plant density was 20 plants/m² under conditions of semi-arid regions.

Keywords: irrigation regime, Cicer arietinum, chickpea, plant density

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Authors: Soufiene Ilahi

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Photothermal effect occurs when absorbed light energy that generate a thermal wave that propagate into the sample and surrounding media. Subsequently, the propagation of the vibration of phonons or electrons causes heat transfer. In fact, heat energy is provided by non-radiative recombination process that occurs in semiconductors sample. Three heats sources are identified: surface recombination, bulk recombination and carrier thermalisation. In the last few years, Photothermal Deflection Technique PTD is a nondestructive and accurate technique that prove t ability for electronics properties investigation. In this paper, we have studied the influence of doping on minority carrier lifetime, i.e, nonradiative lifetime, surface and diffusion coefficient. In fact, we have measured the photothermal signal of two sample of GaAs doped with C et Cr.In other hand , we have developed a theoretical model that takes into account of thermal and electronics diffusion equations .In order to extract electronics parameters of GaAs samples, we have fitted the theoretical signal of PTD to the experimental ones. As a results, we have found that nonradiative lifetime is around of 4,3 x 10-8 (±11,24%) and 5 x 10-8 (±14,32%) respectively for GaAs : Si doped and Cr doped. Accordingly, the diffusion coefficient is equal 4,6 *10-4 (± 3,2%) and 5* 10-4 (± 0,14%) foe the Cr, C and Si doped GaAs respectively.

Keywords: nonradiative lifetime, mobility of minority carrier, diffusion length, surface and interface recombination in GaAs

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Authors: R. Sabre, W. Horrigue, J. C. Simon

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This paper is interested in two difficulties encountered in practice when observing a continuous time process. The first is that we cannot observe a process over a time interval; we only take discrete observations. The second is the process frequently observed with a constant additive error. It is important to give an estimator of the spectral density of such a process taking into account the additive observation error and the choice of the discrete observation times. In this work, we propose an estimator based on the spectral smoothing of the periodogram by the polynomial Jackson kernel reducing the additive error. In order to solve the aliasing phenomenon, this estimator is constructed from observations taken at well-chosen times so as to reduce the estimator to the field where the spectral density is not zero. We show that the proposed estimator is asymptotically unbiased and consistent. Thus we obtain an estimate solving the two difficulties concerning the choice of the instants of observations of a continuous time process and the observations affected by a constant error.

Keywords: spectral density, stable processes, aliasing, periodogram

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Authors: Tim Bolle, Franziska Kreimendahl, Thomas Gries, Stefan Jockenhoevel

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The therapeutic treatment of extensive, deep wounds is limited. Autologous split-skin grafts are used as a so-called ‘gold standard’. Most common deficits are the defects at the donor site, the risk of scarring as well as the limited availability and quality of the autologous grafts. The aim of this project is a tissue engineered dermal-epidermal skin replacement to overcome the limitations of the gold standard. A key requirement for the development of such a three-dimensional implant is the formation of a functional capillary-like network inside the implant to ensure a sufficient nutrient and gas supply. Tailored three-dimensional warp knitted spacer fabrics are used to reinforce the mechanically week fibrin gel-based scaffold and further to create a directed in vitro pre-vascularization along the parallel-oriented pile yarns within a co-culture. In this study various three-dimensional warp knitted spacer fabrics were developed in a factorial design to analyze the influence of the machine parameters such as the stitch density and the pattern of the fabric on the scaffold performance and further to determine suitable parameters for a successful fibrin gel-incorporation and a physiological performance of the scaffold. The fabrics were manufactured on a Karl Mayer double-bar raschel machine DR 16 EEC/EAC. A fine machine gauge of E30 was used to ensure a high pile yarn density for sufficient nutrient, gas and waste exchange. In order to ensure a high mechanical stability of the graft, the fabrics were made of biocompatible PVDF yarns. Key parameters such as the pore size, porosity and stress/strain behavior were investigated under standardized, controlled climate conditions. The influence of the input parameters on the mechanical and morphological properties as well as the ability of fibrin gel incorporation into the spacer fabric was analyzed. Subsequently, the pile yarns of the spacer fabrics were colonized with Human Umbilical Vein Endothelial Cells (HUVEC) to analyze the ability of the fabric to further function as a guiding structure for a directed vascularization. The cells were stained with DAPI and investigated using fluorescence microscopy. The analysis revealed that the stitch density and the binding pattern have a strong influence on both the mechanical and morphological properties of the fabric. As expected, the incorporation of the fibrin gel was significantly improved with higher pore sizes and porosities, whereas the mechanical strength decreases. Furthermore, the colonization trials revealed a high cell distribution and density on the pile yarns of the spacer fabrics. For a tailored reinforcing structure, the minimum porosity and pore size needs to be evaluated which still ensures a complete incorporation of the reinforcing structure into the fibrin gel matrix. That will enable a mechanically stable dermal graft with a dense vascular network for a sufficient nutrient and oxygen supply of the cells. The results are promising for subsequent research in the field of reinforcing mechanically weak biological scaffolds and develop functional three-dimensional scaffolds with an oriented pre-vascularization.

Keywords: fibrin-gel, skin replacement, spacer fabric, pre-vascularization

Procedia PDF Downloads 256

Authors: Luciana P. Mazur, Tatiana A. Pozdniakova, Rui A. R. Boaventura, Vitor J. P. Vilar

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The principal mechanism of metal ions sequestration by brown algae involves the formation of complexes between the metal ion and functional groups present on the cell wall of the biological material. To understand the role of functional groups on copper(II) uptake by Ascophyllum nodosum, some functional groups were chemically modified. The esterification of carboxylic groups was carried out by suspending the biomass in a methanol/HCl solution under stirring for 48 h and the blocking of the sulfonic groups was performed by repeating the same procedure for 4 cycles of 48 h. The methylation of amines was conducted by suspending the biomass in a formaldehyde/formic acid solution under shaking for 6 h and the chemical modification of sulfhydryl groups on the biomass surface was achieved using dithiodipyridine for 1 h. Equilibrium sorption studies for Cu2+ using the raw and esterified algae were performed at pH 2.0 and 4.0. The experiments were performed using an initial copper concentration of 300 mg/L and algae dose of 1.0 g/L. After reaching the equilibrium, the metal in solution was quantified by atomic absorption spectrometry. The biological material was analyzed by Fourier Transform Infrared Spectroscopy and Potentiometric Titration techniques for functional groups identification and quantification, respectively. The results using unmodified algae showed that the maximum copper uptake capacity at pH 4.0 and 2.0 was 1.17 and 0.52 mmol/g, respectively. At acidic pH values most carboxyl groups are protonated and copper sorption suffered a significant reduction of 56%. Blocking the carboxylic, sulfonic, amines and sulfhydryl functional groups, copper uptake decreased by 24/26%, 69/81%, 1/23% and 40/27% at pH 2.0/4.0, respectively, when compared to the unmodified biomass. It was possible to conclude that the carboxylic and sulfonic groups are the main functional groups responsible for copper binding (>80%). This result is supported by the fact that the adsorption capacity is directly related to the presence of carboxylic groups of the alginate polymer, and the second most abundant acidic functional group in brown algae is the sulfonic acid of fucoidan that contributes, to a lower extent, to heavy metal binding, particularly at low pH.

Keywords: biosorption, brown marine macroalgae, copper, ion-exchange

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Authors: M. Kakavand, S. A. Naeini

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Dynamic properties of soil in small strains, especially for geotechnical engineers, are important for describing the behavior of soil and estimation of the earth structure deformations and structures, especially significant structures. This paper presents the effect of density on the shear modulus and damping ratio of saturated clean sand at various isotropic confining pressures. For this purpose, the specimens were compared with two different relative densities, loose Dr = 30% and dense Dr = 70%. Dynamic parameters were attained from a series of consolidated undrained fixed – free type torsional resonant column tests in small strain. Sand No. 161 is selected for this paper. The experiments show that by increasing sand density and confining pressure, the shear modulus increases and the damping ratio decreases.

Keywords: dynamic properties, shear modulus, damping ratio, clean sand, density, confining pressure, resonant column/torsional simple shear, TSS

Procedia PDF Downloads 121