Fiber orientation in viscous fluid flow with and without vibration

This early-stage investigation is related to determination of flow speed gradients of fresh steel fiber-reinforced concrete (SFRC). They are assumed to be the key parameters for computer modeling of orientation of steel fibers in form casting process. The aim of the research is to elaborate a computer model for evaluation of steel fiber orientation in casting process, which would provide an attractive possibility to predict concrete mechanical properties, optimization of casting process and costs due to proper use of ingredients. Fiber orientation in FRC is important for ensuring the best mechanical properties in the places where it is necessary. Task can be solved as: to obtain optimal fiber concentration and orientation or to use appropriate casting approach of concrete with the goal to obtain required mechanical properties in appropriate locations of the composite element. As an example the paper considers the case of trench filling by fiber concrete. Simulations provided distributions of vertical and horizontal velocities in real-time scale. Behavior of a single fiber in an inclined container with a viscous transparent liquid (potato-starch solution) was analyzed in order to confirm the possibility to obtain orientation of fibers on the basis of velocity gradients in viscous fluid. For precise modeling of potato-starch liquid, coefficient of dynamic viscosity was determined. The experiments performed on fibers in an inclined container demonstrated satisfactory agreement with the simulation results. Performed analysis indicates that velocity gradients can be applied for determination of position and orientation of fibers in fabrication of fiber-reinforced concrete product

Numerical modeling of fiber pull-out micromechanics in concrete matrix composites

The presented research work compares numerical results of single fiber pull-out of elastic matrix with the experimental data obtained for single steel fiber pulled out of highstrength concrete matrix. The pull-out process was studied by means of accurate 2D elastic and 3D elasto-plastic finite element models taking into account the nonlinearity. Numerical modeling was performed for straight-shaped fiber embedded into the elastic matrix under variable angle with respect to applied pulling force and at variable depth. Friction between fiber and matrix, matrix shrinkage as well as elastic and plastic deformations in the fiber were taken into account. The objective of numerical modeling was to evaluate significance of different phenomena such as friction between steel fiber and concrete matrix, matrix shrinkage and fiber plasticity in a single fiber pull-out process by taking into consideration experimental findings

Fiber orientation in viscous fluid flow with and without vibration

This early-stage investigation is related to determination of flow speed gradients of fresh steel fiber-reinforced concrete (SFRC). They are assumed to be the key parameters for computer modeling of orientation of steel fibers in form casting process. The aim of the research is to elaborate a computer model for evaluation of steel fiber orientation in casting process, which would provide an attractive possibility to predict concrete mechanical properties, optimization of casting process and costs due to proper use of ingredients. Fiber orientation in FRC is important for ensuring the best mechanical properties in the places where it is necessary. Task can be solved as: to obtain optimal fiber concentration and orientation or to use appropriate casting approach of concrete with the goal to obtain required mechanical properties in appropriate locations of the composite element. As an example the paper considers the case of trench filling by fiber concrete. Simulations provided distributions of vertical and horizontal velocities in real-time scale. Behavior of a single fiber in an inclined container with a viscous transparent liquid (potato-starch solution) was analyzed in order to confirm the possibility to obtain orientation of fibers on the basis of velocity gradients in viscous fluid. For precise modeling of potato-starch liquid, coefficient of dynamic viscosity was determined. The experiments performed on fibers in an inclined container demonstrated satisfactory agreement with the simulation results. Performed analysis indicates that velocity gradients can be applied for determination of position and orientation of fibers in fabrication of fiber-reinforced concrete product

Mathematical model of «engine - power supply system with a mixture Of diesel and biodiesel»

В даній статті розглядається математична модель системи «двигун – система живлення сумішшю дизельного та біодизельного палив». Наведена методика визначення раціонального відсоткового складу суміші за умови максимального використання біодизельного палива та забезпечення необхідних параметрів роботи двигуна.В данной статье рассматривается математическая модель системы «двигатель - система питания смесью дизельного и биодизельного топлив». Приведена методика определения рационального процентного состава смеси при максимальногоBiodiesel has not gained widespread because it is more commonly used mixture with diesel fuel. However, mixtures with a low content of biodiesel cannot fully use the potential of biodiesel. but increased its content in the mixture manifests its negative aspects. Therefore, this article is devoted to the definition of rational percentage composition of the mixture depending on the operating mode of the engine. This paper deals with a mathematical model of the system "Engine - power supply system with a mixture of diesel and biodiesel fuels." Power system provides a dynamic change in the percentage composition of biodiesel and diesel fuels. This definition of rational percentage of the mixture of biodiesel and diesel fuel, provided the maximum use of biodiesel. The resulting mixture should provide equivalent characteristics and specifications when operating on diesel fuel. The criteria for evaluation were taken power and duration of injection and combustion of fuel mixture, that determine the content of biodiesel in the blend and cyclic fuel supply. Dynamic management of percentage structure somewhat complicates the construction, but also provides an opportunity to make the most of the advantages of each of the fuels. The system is universal, as an alternative you can use other fuels. Knowing their chemical and physical properties, the mathematical model provide the necessary operating parameters of the engine power

Критерії навчання нечіткого класифікатора на основі відстані між головними конкурентами

Класифікація це віднесення об`єкта за деякими ознаками до одного з класів. До класифікації зводяться різноманітні задачі прийняття рішень в інженерії, економіці, медицині, соціології та в інших областях. В нечітких класифікаторах залежність «входи – вихід» описуються за допомогою лінгвістичних правил , антецеденти яких містять нечіткі терми «низький», «середній», «високий» тощо. Для підвищення безпомилковості нечіткий класифікатор навчають за експериментальними даними. В даній роботі запропоновано нові критерії навчання нечіткого класифікатора, які враховують різницю належностей нечіткого висновку лише до головних конкурентів. За правильної класифікації головним конкурентом прийнятого рішення є клас, що має другий за величиною ступінь належності. У випадку неправильної класифікації помилково прийняте рішення є головним конкурентом правильного класу. Проведені комп`ютерні експерименти із навчання нечіткого класифікатора для розпізнавання трьох сортів італійських вин засвідчили суттєву перевагу нових критеріїв. Серед нових критеріїв помірну перевагу має критерій на основі квадратичної відстані між головними конкурентами з штрафом за помилкове рішення. Нові критерії можуть застосовуватися не лише для навчання нечітких класифікаторів, але і для навчання деяких інших моделей, наприклад, нейронних мереж.The classification problem is the assignment an object with certain features to one of classes. Various engineering, management, economic,political, medical, sport, and other problems are reduced to classification. In fuzzy classifiers «inputs – output» relation is described by linguistic rules. Antecedents of these rules contain fuzzy terms «low», «average», «high» etc. To increase the correctness it is necessary totune the fuzzy classifier on experimental data. The new criteria for fuzzy classifier learning that take into account the difference ofmembership degrees to the main competitors only are proposed. When the classification is correct, the main competitor of the decision is theclass with the second largest membership degree. In cases of misclassification the wrong decision is the main competitor to the correct class.Computer experiments with learning the fuzzy classifier of 3 kinds of Italian wines recognition showed a significant advantage of the newcriteria. Among new learning criteria the criterion in the form of squared distance between main competitors with the penalty for wrongdecision has minor advantage. New criteria can be used not only for tuning fuzzy classifiers but for tuning some other models, such as neuralnetworks

Atrasentan and renal events in patients with type 2 diabetes and chronic kidney disease (SONAR): a double-blind, randomised, placebo-controlled trial

Background: Short-term treatment for people with type 2 diabetes using a low dose of the selective endothelin A receptor antagonist atrasentan reduces albuminuria without causing significant sodium retention. We report the long-term effects of treatment with atrasentan on major renal outcomes. Methods: We did this double-blind, randomised, placebo-controlled trial at 689 sites in 41 countries. We enrolled adults aged 18–85 years with type 2 diabetes, estimated glomerular filtration rate (eGFR)25–75 mL/min per 1·73 m 2 of body surface area, and a urine albumin-to-creatinine ratio (UACR)of 300–5000 mg/g who had received maximum labelled or tolerated renin–angiotensin system inhibition for at least 4 weeks. Participants were given atrasentan 0·75 mg orally daily during an enrichment period before random group assignment. Those with a UACR decrease of at least 30% with no substantial fluid retention during the enrichment period (responders)were included in the double-blind treatment period. Responders were randomly assigned to receive either atrasentan 0·75 mg orally daily or placebo. All patients and investigators were masked to treatment assignment. The primary endpoint was a composite of doubling of serum creatinine (sustained for ≥30 days)or end-stage kidney disease (eGFR <15 mL/min per 1·73 m 2 sustained for ≥90 days, chronic dialysis for ≥90 days, kidney transplantation, or death from kidney failure)in the intention-to-treat population of all responders. Safety was assessed in all patients who received at least one dose of their assigned study treatment. The study is registered with ClinicalTrials.gov, number NCT01858532. Findings: Between May 17, 2013, and July 13, 2017, 11 087 patients were screened; 5117 entered the enrichment period, and 4711 completed the enrichment period. Of these, 2648 patients were responders and were randomly assigned to the atrasentan group (n=1325)or placebo group (n=1323). Median follow-up was 2·2 years (IQR 1·4–2·9). 79 (6·0%)of 1325 patients in the atrasentan group and 105 (7·9%)of 1323 in the placebo group had a primary composite renal endpoint event (hazard ratio [HR]0·65 [95% CI 0·49–0·88]; p=0·0047). Fluid retention and anaemia adverse events, which have been previously attributed to endothelin receptor antagonists, were more frequent in the atrasentan group than in the placebo group. Hospital admission for heart failure occurred in 47 (3·5%)of 1325 patients in the atrasentan group and 34 (2·6%)of 1323 patients in the placebo group (HR 1·33 [95% CI 0·85–2·07]; p=0·208). 58 (4·4%)patients in the atrasentan group and 52 (3·9%)in the placebo group died (HR 1·09 [95% CI 0·75–1·59]; p=0·65). Interpretation: Atrasentan reduced the risk of renal events in patients with diabetes and chronic kidney disease who were selected to optimise efficacy and safety. These data support a potential role for selective endothelin receptor antagonists in protecting renal function in patients with type 2 diabetes at high risk of developing end-stage kidney disease. Funding: AbbVie

Fiber Orientation in Viscous Fluid Flow with and without Vibration

This early - stage oinvestigation is related to determination of flow speed gradients of fresh steel fiber - reinforced concrete (SFRC). They are assumed to be the key parameters for computer modeling of orientation of steel fiber in form casting process