Calculations Research Articles

Impact of Geotechnical Barrier Modelled in the Vicinity of a Building Structures Located in Mining Area

The paper presents a new geotechnical solution indicating a possibility of effective building structures protection. The presented solutions enable minimization of negative effects of underground mining operations. Results of numerical modelling have been presented for an example of design of preventive ditches reducing the influence of mining operations on the ground surface. To minimize the mining damage or to reduce its reach it is reasonable to look for technical solutions, which would enable effective protection of building structures. So far authors concentrated primarily on the development of building structure protection methods to minimize the damage caused by the underground mining. The application of geotechnical methods, which could protect building structures against the mining damage, was not considered so far in scientific papers. It should be noticed that relatively few publications are directly related to those issues and there are no practical examples of effective geotechnical protection. This paper presents a geotechnical solution indicating a possibility of effective protection of building structures. The presented solutions enable minimization of negative effects of underground mining operations. Results of numerical modelling have been presented for an example of design of preventive ditches reducing the influence of mining operations on the ground surface. The calculations were carried out in the Abaqus software, based on the finite element method.

Use of specific contrast-enhanced CT regions of interest to differentiate renal oncocytomas from small clear cell and chromophobe renal cell carcinomas.

PURPOSE We aimed to examine the usefulness of utilizing a specific contrast-enhanced computed tomog raphy (CT) region of interest (ROI) to differentiate renal oncocytoma (RO) from small clear cell renal cell carcinoma (ccRCC) and chromophobe renal cell carcinoma (chRCC). METHODS A retrospective analysis of pre-contrast phase (PCP), corticomedullary phase (CMP), and nephro graphic phase (NP) contrast-enhanced CT images of the histopathologically confirmed initial cohort (27 ROs, 74 ccRCCs, and 36 chRCCs) was conducted. Small, medium, large, and whole ROIs (S-ROI, M-ROI, L-ROI, and W-ROI, respectively) were utilized for CT attenuation value of tumor (AVT), lesion-to-cortex attenuation (L/C), and heterogeneous degree of tumor (HDT) calcula tions. Differences in these parameters were then compared between RO and ccRCC/chRCC, with receiver operating characteristic (ROC) curves being utilized to gauge the diagnostic utility of the statistically significant parameters. Logistic regression analyses were employed to identify key factors capable of differentiating RO and ccRCC/chRCC, with predictive models further being established. A validation cohort (6 ROs, 30 ccRCCs, and 12 chRCCs) was then employed to vali date the performance of the predictive models. RESULTS Of the parameters evaluated using different ROIs, L/C-CMP (S-ROI) (0.88 ± 0.15 vs. 1.13 ± 0.25, P < .001) and HDT-CMP (W-ROI) (23.02 (12.00-51.21) vs. 37.81 (16.09-89.45), P < .001) were best suited to differentiating RO and ccRCC, yielding respective area under the curve (AUC) values of 0.803 and 0.834. AVT-NP (S-ROI) (122.85 ± 18.87 vs. 86.50 ± 18.65, P < .001) and AVT-NP (M-ROI) (119 (86-167) vs. 81.5 (53-142), P < .001) were better able to differentiate RO and chRCC, yielding respective AUC values of 0.918 and 0.906. Logistic regression analyses revealed that L/C-CMP (S-ROI) and HDT-PCP, as well as AVT-NP (S-ROI) and HDT-CMP, were the primary factors capable of differentiating RO from ccRCC and chRCC, respectively. The predictive model developed to dif ferentiate between RO and ccRCC exhibited a sensitivity of 66.67% and 55.14% in the initial and validation cohorts, respectively, with corresponding specificity of 94.59% and 93.55%, accuracy of 87.13% and 86.84%, and AUC of 0.908 and 0.876. The predictive model developed to differ entiate between RO and chRCC exhibited a sensitivity of 85.19% and 100.00% in the initial and validation cohorts, respectively, with corresponding specificity of 94.59% and 92.86%, accuracy of 87.30% and 95.24%, and AUC of 0.944 and 0.959. CONCLUSION These data demonstrate that a combination of quantitative parameters measured with particu lar ROIs can enable the efficient and reliable differentiation of RO from ccRCC and chRCC for use in routine patient differential diagnosis.

Transistores de Película Delgada Basados en Oxido de Zinc por Spray Pyrolysis Ultrasónico de Alta Frecuencia a Baja Temperatura

En este artículo, se reporta la fabricación de transistores de película delgada con óxido de zinc (ZnO TFTs) sobre sustratos de plástico por spray pyrolysis ultrasónico de alta frecuencia a baja temperatura. La máxima temperatura de fabricación fue de 200°C. Spin-on glass fue usado como dieléctrico de compuerta. El tereftalato de polietileno (PET) es usado como sustrato de plástico. Los ZnO TFTs exhiben una movilidad de electrones de 1.25 cm2/Vs y voltaje de umbral de 10.5V, mientras la relación de corriente on/off fue de 104. Adicionalmente, la densidad de trampas en la capa activa y en la interfaz dieléctrico/semiconductor son calculados. Además, capacitores metal-dieléctrico-metal fueron fabricados sobre plástico y caracterizados para evaluar el dieléctrico de compuerta.

In The Solution of Nonlinear Equation

In this work, we present numerical method in order to solve non-linear equation of solar cell based on single diode model using two suitable approximations; Illinois Algorithm and Classic Chord techniques. Algorithms have discussed the tolerances of the values. It is founded that the new proposed method has the lesser number of evaluations than the other ones. Numerical examples are presented in order to test the efficiency, accuracy and the performance of this method. Numerical calculations observe that the proposed method is compatible with the famous existing methods and in this case gives the better results. The results obtained explain that the new suggested technique is more easy, accurate to use and efficient than other numerical methods are introduced.

Türkiye Şeftali Piyasasının Ekonomik Analizi ve Pazarlama Marjları

Çalışmada gıda sanayisine ham madde oluşturması, insan sağlığına sunduğu katkılar, enerji kaynağı ve gübre olarak kullanılabilmesi gibi özellikleriyle her geçen gün önemi artan şeftali piyasasının analizi amaçlanmıştır. Veri seti; TÜİK ve TOB istatistiklerinden temin edilen 2003-2017 yıllarına ait; üretici fiyatı, tüketici fiyatı, üretim, tüketim, ihracat, ithalat ve girdi fiyatlarına ilişkin verilerden oluşturulmuştur. Türkiye şeftali piyasasını analiz etmek amacıyla; arz ve talep fonksiyonları ile ilgili modeller tahmin edilmiş, pazarlama marjı ve zincirleme indeks hesaplamaları yapılmıştır. Regresyon tahmin sonuçları, üretim üzerinde; gübre fiyatlarının negatif yönlü, tarımsal işgücü ücretlerinin ise pozitif yönlü bir ilişki içerisinde olduğunu ortaya koymuştur. Talep üzerinde pozitif yönlü etkiye sahip faktörün nüfus olduğu belirlenmiştir. Reel fiyatlara göre; ortalama pazarlama marjı 0.60 TL kg-1, üreticinin eline geçen değer %53.92 olarak hesaplanmıştır. 2008-2011 yılları arasında ortalama %60.92 olan reel üreticinin eline geçen değerin 2017 yılına gelindiğinde %48.28 oranına gerilemesi; piyasada her geçen yıl elde edilen kazançtan üreticiye daha az pay düştüğünün göstergesidir. Üreticinin eline geçen değer artarken pazarlama marjının azalması hem üretici hemde tüketicinin lehine olacağı için, üreticilerin kooperatifler gibi pazarlama marjını azaltabilecek oluşumlara teşvik edilmesi önem taşımaktadır.

An Automatic Vehicle Routing and Tracking Technique Based on Video and Image Processing Techniques

In this research work an advanced route tracking application is designed based on video and image camera stabilization technique. The initial input video can convert the images and contain noise as well as extreme distortions. Therefore the following elements can affect the route tracking as well as mis-information gathering. In this paper a multi-media tool based mute tracking application is introduced to obtain mad condition as well as route features. The initial images are filtered by using adaptive median filter to minimize the noise. After filtration road condition can easily identified and separate the target and background, moreover the boundary conditions helpful for extracting the neighborhood target images. The following process is working based on angle, derivative-path and curvature calculations. After this primary process, preview image can be obtained on the screen, according to this the driving speed can be controlling to front wheel rotations. The random pursuit matching algorithm controls the later information and realization. The experimental outcomes show that proposed application has been helpful for driver less vehicle tracking easily. This investigation had been verified on various references speeds and managed with 0.04 meters.

Investigation of University Students' in-Class Smartphones Usage with Association Rules

This study aimed to investigate the university students' usage of smartphones in-class and reveal the relationships among the frequency of use, the purpose of use, reasons for the smartphone using in course, and demographic variables (gender and class). To achieve this aim, we used the correlational survey model. The study sample was selected from the students studying in an Education Faculty of a University in the east of Turkey in the spring semester of 2019-2020 academic year. The sample determined by the snowball sampling method consisted of a total of 577 students. The survey technique was used to collect data. The descriptive and relation analysis were used in the analysis of the data. Frequency and percentage calculations were made for descriptive analysis. For relational analysis, the association rule, one of the data mining methods, was used. It has been revealed that most of the students use their smartphones occasionally and mostly in messages, to do research and connect to social networks. It was observed that the main reasons that motivated students to use their smartphones in the courses were doing research about the course and using them in emergencies. Besides, students gave close answers about the effect of smartphone use on academic performance, and most of the students stated that they did not have difficulty focusing when using smartphones in the courses. Some students also stated that they did not use the phone as it distracted them, and it was forbidden to use it in the course. Results revealed that the boring course, negative attitudes towards the lecturer, and the course cause students to message and connect to social media. It was concluded that the occasional use of smartphones in the courses in cases of emergency and messaging does not affect students' academic performance and does not cause any problems in focusing on the course. Besides, most people who use their smartphones for researching, reading news, and messaging in the courses stated that they use their smartphones for educational purposes. Some suggestions were developed at the end of the study based on the results.

INVESTIGATION OF KNOWLEDGE OF MATHEMATICS TEACHERS ABOUT PROBABILITY PROBLEMS

The probability subject and problems about this subject can cause some difficulties for teachers as well as for students. In this context, this study aims to investigate the knowledge and opinions of mathematics teachers about the subject of probability. This research was designed as a case study, which is one of the qualitative research designs. The sample of the study consisted of a total of 28 mathematics teachers, 18 of whom were females and 10 of whom were males, working in state schools in a southern city of Turkey. In addition, interviews were also conducted with a total of 8 mathematics teachers, 6 females and 2 males, among the teachers who participated in the study in order to investigate their general opinions about the subject of probability. In order to collect data, the probability problems test was used to determine the knowledge of mathematics teachers about probability problems, and a semi-structured interview form was used to investigate their general opinions on probability. The results of the research showed that the teachers’ rate of determining the type of probability problems correctly was 80.6 %. It was also seen that the 37.75% of the mathematics teachers used formulas, 29.6% of them used procedural methods and 31.60% of them used graphical methods in the calculations to solve probability problems. Article visualizations:

ADOPSI TECHNOLOGY ACCEPTANCE MODEL (TAM) TERHADAP PERILAKU MINAT GENERASI MILENIAL DALAM BERINVESTASI DI PASAR MODAL

This study aims to determine the effect of technology acceptance on the interests of the millennial generation to invest in the capital market. The adoption of the TAM model was used in this study, with a quantitative descriptive method approach, data collection using a questionnaire with a sample of 135 people based on calculations with the Slovin formula. Data were analyzed using smart partial least square. The results of this study provide answers to the proposed hypothesis in which the variable perceived ease of use, perceived usefulness, perceived enjoyment have a positive and significant effect on the variable of behavioral intention to use, then the variable perceived enjoyment and behavioral intention to use also have a positive and significant effect on variables actual to use, but there is one variable that does not significantly influence the effect of the variable perceived usefulness on the variable actual to use. This research clarifies how the role of technology applied in online stock trading can influence the behavior of the interests of investors in the Indonesian capital market, especially among millennials. This research is expected to be useful for the development of science and for the development of capital markets with a clearer understanding of how the TAM model influences the behavior of millennial generation interests to become investors in the capital market.

Dynamic response of functionally graded plates with a porous middle layer under time-dependent load

A dynamic analytical solution for a simply supported, rectangular functionally graded plate with a porous middle layer under time-dependent load based on a refined third-order shear deformation theory with a cubic variation of in-plane displacements according to the thickness and linear/quadratic transverse displacement is presented. The solution achieved in the trigonometric series form and rests on the Green's function method. Two porosity types and their influence on material properties, and mechanical behavior are considered. The network of pores is assumed to be empty or filled with low-pressure air, and the material properties are calculated using the power-law distribution idealization. Numerical calculations have been carried out to demonstrate the accuracy of the kinematic model for the dynamic problem, the effect of porosity, thickness of porous layers, power-law index, and type of loading on the dynamic response of an imperfect functionally graded material plate.

Performance prediction of flat sheet commercial nanofiltration membrane using Donnan-Steric Pore Model

The rejection of sodium chloride (NaCl) and calcium chloride (CaCl2) single salt solutions were carried out for commercial nanofiltration NFDK membrane. Results showed that the NFDK membrane had a negative surface charge and had a higher observed rejection of 93.65% for calcium (Ca2+) ion and 78.27% for sodium (Na+) ions. Prediction of rejection for aqueous solutions of both salts was made using Donnan Steric Pore Model based on Extended Nernst-Planck Equation in addition to concentration polarization film theory. A MATLAB program was developed to execute the model calculations. Absolute Average Relative Error (% AARE) was found below 5% for real rejection of the NFDK membrane. This research could be used successfully to assess the membrane characterization parameter using a proposed procedure which can reduce the number of experiments.

Water and Dioxide Carbon Effects on Di or Tri Saccharides Degradation by Density Functional Theory at Level: B3LYP/6-311++G (d, p)

Storing paddy rice over a long period changes its physical properties. It transforms its chemical structure. But the mechanism of this degradation remains little known. This work aims to help elucidate it. It’s studying the possibilities of hydrogen bonding between the di or the trisaccharide with water or carbon dioxide. This research uses the methods of quantum chemistry. These make it feasible to determine the geometric and energy parameters of the complexes. These supramolecules consist of di or trisaccharide associated with water or carbon dioxide. The calculations lead to the following result. The trisaccharide remains stable during its interactions with water and carbon dioxide, the latter strengthening the hydrogen bonds of the complex disaccharide-water. It disadvantages its degradation.

Criação e usos do aplicativo LineAlg como objeto de aprendizagem na Educação Básica

RESUMO: O letramento matemático é indispensável aos processos educativos que têm por finalidade a formação de pessoas capazes de exercer plenamente sua cidadania. A escola contemporânea também não pode prescindir de tecnologias como a dos computadores e dos dispositivos eletrônicos móveis. Este trabalho articulou ambas as necessidades com o objetivo de desenvolver um aplicativo para auxiliar processos de ensino-aprendizagem de matrizes, determinantes e sistemas de equações lineares no Ensino Médio. Para tanto, houve a realização de pesquisas bibliográficas sobre o ensino desses tópicos da álgebra linear e, consequentemente, o desenvolvimento de uma aplicação móvel utilizando a linguagem Python e a biblioteca Kivy. Foram criadas funções que permitem calcular e verificar o passo a passo dos cálculos, bem como tomar lições por meio de um chatbot, ainda uma aplicação para o balanceamento de equações químicas. Além desses usos, sugere-se uma atividade com o aplicativo, a fim de evidenciar seu potencial de incrementar aulas de matemática e estudos individuais dos alunos em tópicos de álgebra, inclusive de forma remota.&#x0D; PALAVRAS-CHAVE: Ensino de Matemática, Tecnologias digitais, Álgebra linear.

Derivation of Analytical, Closed‐form Formulas for the Calculations of Instantaneous Screw Axes of Arbitrary Rigid 3D Multi‐Body Systems

Derivation of Analytical, Closed‐form Formulas for the Calculations of Instantaneous Screw Axes of Arbitrary Rigid 3D Multi‐Body Systems

Gluten-free Foods and Their Contribution to Total Diet in Patients with Celiac Disease

Background. Gluten-free diet continues being the most effective treatment of celiac disease but current evidence on its nutritional characteristics and metabolic effects rises concerns. Objectives. To assess the total diet of adult celiac patients and the contribution of gluten-free foods to it, in Chilean celiac patients. Methodology. Sociodemographic and clinical characteristics were registered and a food frequency questionnaire including detailed data about gluten-free foods was applied to 71 celiac patients older than 12 years of age receiving medical care at INTA, University of Chile, in Santiago. Total food intake, dietary adequacy and diet nutritional quality was calculated using descriptive statistics. Principal Findings. Of 71 patients, 81.6% were female, 93% were 19-65 years of age and 65% were on GFD for 2 years or more. Nutritional status classified in underweight and overweight/obesity in 2.9% and 35.7%, respectively. 2.8% patients declared to consume willingly gluten containing bread. The whole diet was normocaloric, normoproteic, hyperlipidic and hypoglucidic (FAO/WHO); when calculations were based for individuals’ requirements, 65% of cases consumed excess calories, proteins, and carbohydrates. Gluten-free foods contributed to 17.7%, 11.6%, 11.5% and 23.9% of the total daily intake of calories, protein, lipids, and carbohydrates, respectively. GFF were characterized by having a low protein content. Conclusions. Although the whole diet appeared close to WHO/FAO recommendations when calculated as average for the study group, 65% of participants consumed excess calories, proteins, lipids, and carbohydrates when calculations were made on individual basis. There was neither moderate-severe undernutrition nor overweight/obesity in the group studied. It is interesting that both the total diet quality and the nutritional status of the celiac patients assessed were better than those described in the general local population.

Approximate calculation of the static analysis of a lifted stay cable in super-long span cable-stayed bridges

The sag effect of long stay cables is one of the key factors restricting further increase in the span of cable-stayed bridges. Based on the formerly proposed concept of long stay cables lifted by an auxiliary suspension cable in cross-strait cable-stayed bridges, corresponding static approximate calculations and analytical theory based on catenary and parabolic cable configurations are established. Taking a main span 1400 m cable-stayed bridge as the research object, three typical lifting conditions and the whole process of auxiliary cable lifting are analyzed and discussed. The results show that the sag effect is effectively reduced. The support efficiency is only improved when the cables are lifted above the original cable chord. Reduction of the horizontal component force of the cable is limited. The equivalent elastic modulus and the vertical support stiffness of the lifted cables are significantly increased with increased horizontal projection length and not sensitive to the change of the lifting point position. The scheme of lifting the cable to the chord midpoint is more economical because of the less steel required for the auxiliary suspension cable, but its effect on improving the vertical support efficiency is limited. The support efficiency is better when the cable is lifted to the cable end tangential to the original cable chord, but the lifting force and the cross-sectional area of the auxiliary suspension cable are doubled. The approximate calculation results of the lifted cables are very close to the numerical analysis results, which verifies the applicability of the approximation method proposed in this study. The results of parabolic approximation calculations are approximately equal to that of catenary cable geometry. As the parabolic approximation analysis theory of lifted cables is more convenient in mathematical processing, it is feasible to use parabolic approximation analysis theory as the analytical method for the conceptual design of lifted cables of super-long span cable-stayed bridges.

Host rock peculiarities and influence of major structures on gold and base metal sulfide mineralization in northern Pakistan

For decades, the streams and rivers in northern areas of Pakistan are being explored for gold but the source rock for primary gold is yet to be located. Recent geological surveys have identified several areas for follow-up study for Cu-Au mineralization in Chitral and Gilgit-Baltistan regions. The rocks exposed at various localities are variably altered and/ or mineralized and intensely deformed, which mostly include diorite, granodiorite, greenschists, limestones and undeformed volcanic rocks and granitoids of the Kohistan island arc. The results of petrographic and X-ray diffraction (XRD) analyses of a variety of representative rock samples from a number sites have revealed that mineralization in the Chitral and Gilgit-Baltistan regions is dominantly in the form of pyrite, tetrahedrite, chalcopyrite and galena with subordinate amounts of magnetite, malachite and azurite. The associated/ gangue minerals include albite, quartz, actinolite, biotite, chlorite, epidote, calcite, garnet, illite and titanite (sphene). Diffraction patterns of glycolated samples did not show the existence of swelling clay (e.g., smectite). Sericitic, chloritic and carbonatic alterations have been observed in the studied altered rocks. Mass balance calculations indicate that most of the sulfide-bearing samples are enriched in Cu, Au, Sb, As and Pb and depleted in the rest of the metals reflecting differences in elements mobility during the ore-forming processes. Some of the mineralized rocks especially limestone have experienced a significant volume change due to mobilization of some of the major element oxides e.g. CaO, Fe2O3, SiO2 and ore-forming components e.g. Cu and Pb. The mineralization is of epithermal type in most of the investigated sites, however a few areas show ore formation though orogenic processes and very rarely the ore deposit displays features of the volcanogenic massive sulfide type. Some of the areas are quite promising with respect to their ore element contents and the highly mineralized zones lie in close proximity to major structures in the region. Besides, results from the current study indicate that the mineralization shows close spatial association and hence a strong genetic link with strike slip faults especially where they bend and merge together.

Developing A Method for Inter-Seed Effect Correction in 125I Interstitial Brachytherapy Using Artificial Neural Network

Introduction: Treatment planning systems use TG-43 dose calculation protocol for brachytherapy sources. Dose calculations based on TG-43 formalism do not correct the perturbations due to the presence of tissue inhomogeneity, applicators, and inter-seed effects. Inter-seed attenuation has an important effect on dosimetry in permanent implant brachytherapy. The aim of this study is to evaluate the inter-seed attenuation effect for I-125 permanent implants. Then, a software was developed to find the real dose distribution for different combinations of sources. Materials and methods: In the first step, a hypothetical generic source model was designed based on the configurations of different commercial source types. MCNP5 Monte Carlo code was utilized to simulate the single active generic source at the center of the phantom, and an inactive placed at various positions inside the phantom. An algorithm was introduced using artificial neural network models that can estimate the dose distribution in presence of inactive sources. Results: The Monte Carlo calculation results showed that the dose distribution is clearly affected by the inter-seed attenuation effect. Comparison of the artificial neural network results with the Monte Carlo simulation results show that the artificial neural networks can predict the inter-seed attenuation with acceptable accuracy, and with not much greater than 3% deviation.Discussion and conclusions: Inter-seed effect is dependent on the distance between the seeds. Decreasing distances would cause more effect. According to the results, it seems that the artificial neural network can be used as a tool for correction of inter-seed attenuation effect in treatment planning systems.

Vertical load on a conduit buried under a sloping ground

Conduits are commonly installed below the ground for utility conveyance around the world. Vertical load on a buried conduit is an important parameter that needs to be known to ensure its safe design and installation. Consideration of soil arching in load calculations helps achieve a more realistic and efficient design. In the past, considering the arching effect, the design charts have been presented for use by practicing engineers to calculate the vertical load on the conduit buried below the level ground. There are currently no design charts for calculating the vertical load on the conduit buried under a sloping ground. In this paper, an attempt has been made to present the derivation of a generalized analytical expression considering that the soil mass overlying the conduit has a sloping face and the arching phenomenon takes place. The developed generalized expression has been used to present some design charts considering specific values of slope geometry, soil properties and burial depths. Furthermore, analytical results for specific soil parameters have been compared with the results extracted from a commercial software PLAXIS 2D, for a developed numerical model and an independent study.

A unified approach to shear and torsion in reinforced concrete

Reinforced concrete (RC) beams can be subjected to a complex combination of shear forces (V), torsional moments (T), flexural moments (M) and axial loads (N). This paper proposes a unified approach for the analysis of these elements. An existing model for the analysis of orthogonally reinforced concrete membrane elements subjected to in-plane shear and normal stresses is generalized to apply to the case of beams subjected to the complex loading. The combination of V and T can be critical. Torsion is modelled using the hollow-tube analogy. A direct equation for the calculation of the thickness of the equivalent hollow tube is proposed, and the shear stresses caused by V and T are combined using a simple approach. The development and the evaluation of the model are described. The calculations of the model are compared to experimental data from 350 beams subjected to various combinations of stress-resultants and to the calculations of the ACI and the CSA codes. The proposed model provides the most favorable results. It is also shown that it can accurately model the interaction between V and T. The proposed model provides a unified treatment of shear in beams subjected to complex stress-resultants and in thin membrane elements subjected to in-plane stresses.