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Представлены результаты исследований состава органических кислот интродуцированных, селекционных и аборигенных сортов винограда и виноматериалов для коньячного производства. Показано, что селекционные сорта винограда Первенец Магарача и Рислинг Магарача, а также интродуцированные сорта Коломбар, Совиньон зеленый, Ркацители при достижении технической зрелости способны накапливать высокий уровень содержания органических кислот, который зависит от климатических условий года и зоны произрастания винограда. Наиболее высокая доля винной кислоты отмечена в образцах винограда сортов Коломбар, Ркацители и Первенец Магарача, а наиболее низкая - в сорте винограда Совиньон зеленый, в составе органических кислот которого превалировала яблочная кислота. В сорте винограда Шабаш, отличающегося низкими значениями содержания титруемых кислот, отмечено минимальное значение суммарной доли винной и яблочной кислот. Анализ компонентов ароматобразующего комплекса коньячных виноматериалов из винограда, достигшего технической зрелости, выявил тесную обратную зависимость между показателями массовой концентрации титруемых кислот в винограде и суммы летучих компонентов виноматериалов, в том числе летучих кислот и высших спиртов. Установленные закономерности позволят регулировать содержание высших спиртов в коньячных дистиллятах с целью улучшения их качества.The organic acid composition of fruits and wine materials for brandy production was studied in European, newly-bred and autochthonous grape varieties. On attaining industrial ripeness, the newly-bred varieties ‘Pervenets Magaracha’ and ‘Riesling Magaracha’ as well as the introduced varieties ‘Colombar’, ‘Sauvignon vert’ and ‘Rkatsiteli’ accumulated high levels of organic acids depending on the climatic conditions of the year and the growing area. The highest proportion of tartaric acid was found in ‘Colombar’, ‘Rkatsiteli’ and ‘Pervenets Magaracha’ grapes while fruits of ‘Sauvignon vert’ had the lowest proportion of this component, with malic acid as its prevailing organic acid. The lowest summated proportion of total tartaric and malic acids was recorded in fruits of ‘Shabash’, the variety known for its low titratable acidity. Analysis of components of the aroma-forming complex of brandy wine materials derived from the study grapes at industrial ripeness revealed a close reverse interrelationship between titratable acidity of the study grapes and the sum of volatile components of the wine materials, including volatile acids and higher alcohols. The established regularities will make it possible to control levels of higher alcohols in brandy distillates to improve their quality.

Одной из важнейших проблем качества винопродукции является ее стабильность, обеспеченная научно обоснованными методами диагностики и приемами технологической обработки с целью предотвращения возникновения дестабилизации. Причиной кристаллообразования является нарушение ионного равновесия под влиянием изменений концентрации катионов и анионов, наличием в системе стимуляторов и ингибиторов этого процесса. Одним из тестов на склонность к кристаллическим помутнениям вин является показатель «температура насыщения», который рассчитывают по разнице электропроводности до и после добавления битартрата калия (Т(КНТar)). Целью работы являлось выявление взаимосвязи между компонентным составом вина и его физико-химическими свойствами, выраженными рН и Т(КНТar). Объектами исследований были белые и красные столовые сухие виноматериалы и вина. В образцах были определены рН, температура насыщения битартратом калия, содержание ионов калия, винной кислоты и ее форм. Объем выборки составил 83 образца. В результате исследования было установлено, что стабильные белые вина характеризовались значениями Т(КНТar) в интервале 10,9-13,5 С, красные вина - 14,4-16,8 С. Выявлена и математически описана взаимосвязь между показаниями теста кристаллической дестабилизации вина и содержанием участников процесса, которую обусловливает массовая концентрация битартрат-ионов, зависящая от величины рН и содержания винной кислоты. Результаты будут использованы для усовершенствования системы диагностики вин при оценке их склонности к кристаллической калиевой дестабилизации.Stability is an important element of the quality of wine and must be enabled by science-based diagnostic methods and treatment technologies with the view to prevent destablization. Crystal formation is caused by ionic imbalances as affected by changes in cation and anion levels and the presence of promotors or inhibitors of this process in the system. Potassium bitartrate saturation temperature (Т(КНТar)) is an index to be relied on while testing wines for liability to crystal haze, and is calculated by the difference in the conductivity measurements prior to and after the addition of potassium bitartrate. The study was aimed to reveal an interrelationship between the componential composition of wine and its physico-chemical characteristics in terms of рН и Т(КНТar). Red and white dry table wines and wine materials were used as objects of research. The sample number was formed by a total of 83 samples in which pH, saturation temperature Т(КНТar) and levels of ions of potassium, tartaric acid and its forms were measured. The Т(КНТar) values of stable white wines varied within 10.9-13.5С, and the Т(КНТar) values of stable red wines ranged from 14.4 to 16.8С. An interrelationship between the data derived from the test for crystalline destabilization of wine and the levels of the agents of the process was revealed and mathematically described. This interrelationship is determined by mass concentration of bitartrate ions which depends on pH values and the levels of tartaric acid. The results obtained will be used to improve the diagnostics system of wines in testing for liability to potassium crystalline destabilization.

Результаты исследований последних лет показывают, что внесение воды в сусло или вино нарушает баланс ионов, изменяет значения физико-химических, органолептических и интегральных показателей. Одним из наиболее важных показателей, позволяющих установить добавку воды, является буферная емкость вина (БЕ). Буферная емкость вина представляет собой его способность противостоять изменениям рН после добавления сильной кислоты или основания. Сила кислоты характеризуется константой диссоциации. Её отрицательный логарифм pKa означает значение рН, при котором соотношение недиссоциированной и диссоциированной по I ступени форм кислоты составляет 1:1. Нами модифицирован метод определения буферной емкости, основанный на результатах ацидиметрического (БЕк) и алкалиметрического (БЕщ) титрования вина, с помощью которого можно оценить степень диссоциации органических кислот, соотношение их молекулярных и ионизированных форм, состояние ионов металлов, способность регулировать скорость химических реакций окисления и восстановления. В работе были использованы подлинные сухие белые и красные виноматериалы, полученные в условиях микровиноделия и производства в сезоны виноделия 2017-2018 гг. из винограда сортов Алиготе, Шардоне, Совиньон зеленый, Кокур белый, Каберне-Совиньон, Мерло, Санджовезе. Для изучения влияния разбавления виноматериалов водопроводной водой проводили ее добавку в количестве 10-70 %. Объем выборки составил 131 образец. Разбавление вина водой - это смешивание двух систем, одна из которых (вино) представляет собой раствор, содержащий органические кислоты и их кислые соли, обладающий рН и буферностью. Вода содержит соли жесткости, обусловливающие ее рН, но не обладает буферностью, соизмеримой по величине с той, которая встречается в винопродукции. Изучены некоторые характеристики смеси вина и воды: значение соотношений кислотной и щелочной составляющих буферной емкости, при которых буферные свойства системы меняют свой характер, что соответствует 70 % разбавлению; описаны математические модели процесса внесения воды в вино, позволяющие определить значения в любой точке разбавления, в том числе в контроле. Систематизация всей выборки позволила разделить образцы на два кластера, детерминирующие подлинные и разбавленные вина по показателю буферных свойств (ПБС), установлены значения показателя буферных свойств системы для подлинных (50-80) и разбавленных (80-100) вин.Studies of recent years demonstrate that introduction of water into must or wine upsets the balance of ions, changes the values of physico-chemical, organoleptic and integral indicators. One of the most important indicators to establish the addition of water is the buffering capacity of wine (BC). Buffering capacity of wine is its ability to resist changes in pH after addition of a strong acid or base. Acid strength is characterized by dissociation constant. Its negative pKa logarithm means pH value at which the non-dissociated and dissociated by stage I acid forms ratio is 1: 1. We have modified the method for buffer capacity determination based on acidimetric and alkalimetric wine titration results, which can be used to assess organic acids dissociation degree, the ratio between their molecular and ionized forms, the state of metal ions, the ability to control the chemical oxidation reactions and recovery rate. In our work we used genuine dry white and red base wines obtained in conditions of micro-winemaking and production during the wine-making seasons of 2017-2018 from grapevine cultivars ‘Aligote’, ‘Chardonnay’, ‘Sauvignon verde’, ‘Kokur Belyi’, ‘Cabernet Sauvignon’, ‘Merlot’, ‘Sangiovese’. To study the effect of base wines dilution with tap water, it was added in the amount of 10-70%. The sample size made 131 samples. Dilution of wine with water is the mixing of two systems, one of which (wine) is a solution containing organic acids and their acid salts, possessing a pH and buffering capacity. Water contains hardness salts that determine its pH, but does not possess buffering capacity comparable in quantity to that found in wine products. Certain characteristics of wine-water mixture were studied: the ratio between the acidic and alkaline components of the buffering capacity at which the buffering properties of the system change their nature, which corresponds to 70% dilution; mathematical models of the process of water introduction into wine were described, allowing to determine the values at any point of dilution, including the control. The entire sample systematization allowed dividing samples into two clusters, determining genuine and diluted wines by buffering property index (PBI); the system buffering property values for genuine (50-80) and diluted (80-100) wines were established.

Algorithms for simulation of trains as coupled detailed spatial and simplified one-dimensional models of rail vehicles are considered. Such an approach to train dynamics allows evaluation of in-train forces and their influence on dynamic characteristics related, e.g. to the safety problems or ride comfort. Initially, the method has been developed for the analysis of derailment accidents and further it has been implemented as a mechanical solver in six-degrees-of-freedom train simulator TRENSIM, which features are discussed in the paper. An algorithm for parallelisation on multi-core processors for the simulation of rail vehicles and trains is presented.

Background and objective Numerous autoimmune diseases (AIDs) have been linked to chronic spontaneous urticaria (CSU). Here, we provide the first extensive and comprehensive evaluation of the prevalence of AIDs in patients with CSU and vice versa . Methods A Pubmed and Google Scholar search was performed to identify studies reporting the prevalence of various AIDs in CSU and vice versa published before April 2017. Results The prevalence of individual AIDs in CSU is increased (≥ 1% in most studies vs ≤ 1% in the general population). AIDs with relatively high prevalence in the general population are also quite common in CSU patients, whereas those with low prevalence remain a rare finding in CSU. The rates of comorbidity in most studies were ≥ 1% for insulin-dependent diabetes mellitus, rheumatoid arthritis (RA), psoriasis and celiac disease (CD), ≥ 2% for Graves' disease, ≥ 3% for vitiligo, and ≥ 5% for pernicious anemia and Hashimoto's thyroiditis. Organ-specific AIDs are more prevalent in CSU than systemic (multiorgan or non organ-specific) AIDs. > 2% of CSU patients have autoimmune polyglandular syndromes encompassing autoimmune thyroid disease (ATD) and vitiligo or pernicious anemia. Antithyroid and antinuclear antibodies are the most prevalent AID-associated autoantibodies in CSU. > 15% of CSU patients have a positive family history for AIDs. The prevalence of urticarial rash in AID patients is > 1% in most studies. This rash is more prevalent in eosinophilic granulomatosis with polyangiitis, ATD, systemic lupus erythematosus, RA and CD. Conclusions CSU patients have an increased risk of AIDs, especially adult female patients and those with a positive family history and a genetic predisposition for AIDs, who should be screened for signs and symptoms of AIDs.

According to current guidelines, non-sedative H1-antihistamines (nsAH) are the first-line therapy of chronic spontaneous urticaria (CSU). But even up-dosed antihistamines (to four times the standard dose) produce symptom resolution in less than 50% of patients. Biomarkers that can predict the response to nsAH are still unknown. We carried out a prospective study and used discriminant analysis to evaluate the combination of D-dimer, fibrinogen, C-reactive protein and ESR values for predicting the outcome of treatment with levocetirizine in 84 CSU patients. We found that elevation of these parameters is associated with more active disease, low quality of life and lack of response to standard doses of levocetirizine. Thus, evaluation of these markers may be considered useful before starting treatment with nsAH. The mechanisms behind the increase in these parameters in CSU patients need to be elucidated in further studies.

Chronic urticaria (CU) is a widespread skin disease, characterized by the recurrence of transient wheals and itch for more than 6 weeks. Besides autoimmune mechanisms, coagulation factors, in particular tissue factor and thrombin, might also participate in the disease pathophysiology. Tissue factor expressed by eosinophils can induce activation of blood coagulation generating thrombin which in turn can increase vascular permeability both directly, acting on endothelial cells, and indirectly, inducing degranulation of mast cells with release of histamine, as demonstrated in experimental models. D-dimer, a fibrin degradation product, generated following activation of the coagulation cascade and fibrinolysis, has been found to be increased during urticaria exacerbations; moreover, it has been proposed as a biomarker of severity and resistance to H1-antihistamines in CU patients. The possible role of coagulation in CU is also supported by case reports, case series and a small controlled study showing the efficacy of anticoagulant therapy in this disease. The purpose of this review was to summarize the available data on the possible contribution of coagulation to the pathophysiology of CU focusing on clinical aspects and possible future therapeutic developments.

Computer models of freight cars with three-piece and Y25 bogies are considered and compared. Efficient numeric methods for simulation of vehicle models in the presence of frictional contacts are discussed. Some simulation results on derailment safety analysis and influence of track gauge value on freight-car dynamics are presented. Methods of stress loading and durability analysis based on computer simulation and some results are presented. A tribodynamic model of railway vehicle-track interaction and results of computation of wheel and rail profile wear are discussed.

Serious problems with wheel and rail profile design arise particularly when combined freight and passenger traffic exists on the line or this task should be solved on a big railway network scale. Profile selection policies and real practices are described. An example of practical approach to profile evaluation is given. A scientific approach to profiles evolution and optimization is described and some results are presented. Some aspects of profile management and control are presented. An approach to profiles evaluation and optimization based on combined scientific and practical methods is described.

Chronic spontaneous urticaria (CSU) is a common mast cell-driven disease characterized by the development of wheals (hives), angioedema (AE), or both for > 6 weeks. It is thought that autoimmunity is a common cause of CSU, which is often associated with autoimmune thyroiditis, whereas the link to other autoimmune disorders such as systemic lupus erythematosus (SLE) has not been carefully explored. Here, we systematically reviewed the existing literature for information on the prevalence of CSU in SLE (and vice versa) and we examined the possible clinical and pathogenetic relationship between CSU and SLE. The prevalence of CSU and CSU-like rash in SLE was investigated by 42 independent studies and comorbidity in adult patients reportedly ranged from 0% to 21.9% and 0.4% to 27.5%, respectively (urticarial vasculitis: 0-20%). In children with SLE, CSU was reported in 0-1.2% and CSU-like rash in 4.5-12% (urticarial vasculitis: 0-2.2%). In contrast, little information is available on the prevalence of SLE in patients with CSU, and more studies are needed to determine the rate of comorbidity. Recent insights on IgG- and IgE-mediated autoreactivity suggest similarities in the pathogenesis of CSU and SLE linking inflammation and autoimmunity with the activation of the complement and coagulation system. Future studies of patients with either or both conditions could help to better define common pathomechanisms in CSU and SLE and to develop novel targeted treatment options for patients with CSU and SLE.

A physically simple but mathematically cumbersome problem of rotating heavy string with one fixed top point was studied. A nonlinear equation of its two-dimensional shapes of relative equilibrium was obtained and solved numerically. A linear case of small displacements was analyzed in terms of Bessel functions. The qualitative and quantitative behavior of the problem is discussed with the help of a bifurcation diagram. Dynamics of the two-dimensional model near the equilibrium positions were studied with the help of a simulation using the absolute nodal coordinate formulation (ANCF); the equilibriums were found to be instable. The reason for instability is explained using a variational principle. The outlines for further full three-dimensional analysis are briefly proposed in this paper, and the full derivation will be explained in the next paper.

A review of the current state of the absolute nodal coordinate formulation (ANCF) is proposed for large-displacement and large-deformation problems in flexible multibody dynamics. The review covers most of the known implementations of different kinds of finite elements including thin and thick planar and spatial beams and plates, their geometrical description inherited from FEM, and formulations of the most important elements of equations of motion. Much attention is also paid to simulation examples that show reasonableness and accuracy of the formulations applied to real physical problems and that are compared with experiments having significant geometrical nonlinearity. Current and further development directions of the ANCF are also briefly outlined.

Many previous studies have conducted computer-aided simulations ofelastic bodies undergoing large deflections and deformations, but therehave not been many attempts to validate their numerical results. Thesubject of this paper is a thin clamped plate undergone large vibrationdue to attached end-point weight. The main aim of this paper is to showthe validity of the absolute nodal coordinate formulation (ANCF) bycomparing to the real experiments. Large oscillations of thin plates arestudied in the paper with taking into account effects of an attachedend-point weight and aerodynamic damping forces. The physicalexperiments are carried out using a high-speed camera and dataacquisition system. For numerical modeling of the plate, the absolutenodal coordinate formulation is used.

Two approaches for simulation of dynamics of complex beam structures such as drill strings are considered. In the first approach, the drill string is presented as a set of uniform beams connected via force elements. The beams can undergo arbitrary large displacements as absolutely rigid bodies but its flexible displacements due to elastic deformations are assumed to be small. Flexibility of the beams is simulated using the modal approach. Thus, each beam has at least twelve degrees of freedom: six coordinates define position and orientation of a local frame and six modes are used for modeling flexibility. The second approach is dynamic simulation of the drill string using nonlinear finite element model. The proposed beam finite element uses Cartesian coordinates of its nodes and node rotation angles around axis of Cartesian coordinate system as generalized coordinates. The nonlinear finite element is developed based on method of large rotation vectors. Rotation angles in the nodes can be arbitrary large. Equations of motion of beam structure are derived in the paper. The number of degrees of freedom is decreased by factor two as compared with the modal approach. Thereby, computational efficiency under simulation of dynamics of long drill strings is considerably increased. The features of creating the models and numerical methods as well as results obtained by applying both approaches are discussed in the paper.

A subsystem technique consisting of a preliminary division of a large multibody system (MBS) into several parts is discussed. The method allows a considerable reduction of efforts on all stages of MBS modeling: description of a system, computer-aided generation of the equations and their integration. Synthesis of the equations of motion including differential and algebraic parts is studied. Numerical methods for efficient integration of the resulting equations are considered.

Numerical methods for the efficient integration of both stiff and nonstiff equations of motion of multibody systems having the form of differential-algebraic equations (DAE) of index 3 are discussed. Linear multi-step ABM and BDF methods are considered for the non-iterational integration of nonstiff DAE. The Park method is proposed for integration of stiff equations.

The selection of optimal operational parameters for drilling oil and gas wells is a complex dynamic problem that depends on multiple parameters. Numerous physical and mechanical processes such as rock cutting, friction, hydraulics, and different modes of vibrations, occur during drilling, which should be accounted for in numerical models. It is widely accepted that bottom hole assembly (BHA) vibrations are the primary source of drilling equipment premature failure. Over the last 30 years, progress of computational sciences has enabled the use of numerical simulations of drillstring dynamics as a useful tool to understand and mitigate sources of harmful vibrations. The majority of these models have been based on nonlinear finite elements. There are several significant limitations with this approach, including an extremely high number of degree of freedom (DOF) required to represent geometries with 105 ratio of axial to lateral dimensions and also the complexity of modeling variable contacts in bifurcating systems. While it is relatively new for simulating drilling dynamics, the advantage of the proposed rigid-flexible multibody system approach has been proven for modeling complex dynamic systems in other industries. Using a rigid-flexible multibody system approach to analyze dynamic effects both in frequency and time domains, dynamic modeling of BHA and drillstring is proposed. Drillstring is simulated as a set of uniform flexible beams connected via linear viscous-elastic force elements. Each beam can undergo arbitrary large displacements as absolutely rigid body, but its flexible displacements due to elastic deformations are small. A method of floating frame of reference for flexible bodies and component mode synthesis is used for modeling beams dynamics. Parameters of the coupling force elements are calculated automatically based on stiffness and inertia characteristics of the connected beams. This paper discusses the development of the rigid-flexible multibody system for modeling drillstring dynamics and the influence of model parameters on simulation accuracy and calculation time. A close match is shown between theoretical and numerical results for static and buckling problems as well as resonant frequency values. Several transient drillstring dynamics problems are analyzed for wellbores with uniform diameter. Examples of the analysis of resonant conditions during drilling planning stage are also presented. It is also shown how transient time domain analysis can provide further insights into lateral and torsional vibrations, whirl behavior, and effect of local wellbore curvatures on the drillstring performance.

A review of the current state of the absolute nodal coordinate formulation (ANCF) is proposed for large-displacement and large-deformation problems in flexible multibody dynamics. The review covers most of the known implementations of different kinds of finite elements including thin and thick planar and spatial beams and plates, their geometrical description inherited from FEM, and formulations of the most important elements of equations of motion. Much attention is also paid to simulation examples that show the reasonableness and accuracy of the formulation applied to real physical problems and that are compared with experiments having significant geometrical non-linearity. Current and further development directions of the ANCF are also briefly outlined.Copyright © 2005 by ASME

Some methods and algorithms for optimal computer-aided modeling of multibody systems are considered. Special approaches to the computerized symbolic generation of motion equations are discussed. The methods described are realized in the program package Universal Mechanism (UM). Their application to modeling technical objects such as a six-legged walking mechanism and spatial cable systems are presented.