One-dimensional dynamics of nearly unstable axisymmetric liquid bridges

A general one-dimensional model is considered that describes the dynamics of slender, axisymmetric, noncylindrical liquid bridges between two equal disks. Such model depends on two adjustable parameters and includes as particular cases the standard Lee and Cosserat models. For slender liquid bridges, the model provides sufficiently accurate results and involves much easier and faster calculations than the full three-dimensional model. In particular, viscous effects are easily accounted for. The one-dimensional model is used to derive a simple weakly nonlinear description of the dynamics near the instability limit. Small perturbations of marginal instability conditions are also considered that account for volume perturbations, nonequality of the supporting disks, and axial gravity. The analysis shows that the dynamics breaks the reflection symmetry on the midplane between the supporting disks. The weakly nonlinear evolution of the amplitude of the perturbation is given by a Duffing equation, whose coefficients are calculated in terms of the slenderness as a part of the analysis and exhibit a weak dependence on the adjustable parameters of the one-dimensional model. The amplitude equation is used to make quantitative predictions of both the (first stage of) breakage for unstable configurations and the (slow) dynamics for stable configurations

ВЛИЯНИЕ ГЕНОТИПА БЫКОВ-ПРОИЗВОДИТЕЛЕЙ ГОЛШТИНСКОЙ ПОРОДЫ НА УРОВЕНЬ НЕКОТОРЫХ ПОКАЗАТЕЛЕЙ АЗОТИСТОГО ОБМЕНА ПОТОМСТВА В УСЛОВИЯХ ЗАПАДНОЙ СИБИРИ

The results of studies of indicators of nitrogen metabolism in the blood serum of the descendants of four bulls at the age of 12-13 months are presented. The studies were conducted in the South of Western Siberia at Vaganovo OJSC on the livestock population of Holstein breed. The creatinine concentration in the blood serum samples of the sons was determined using a set of reagents from Vector-Best (Russia). In the regions of animal breeding, constant monitoring of water, soil, feed, animal organs and tissues is carried out. It was established that in the areas in which the studied breeds were bred, the content of macro- and microelements did not exceed the MPC. The level of serum creatinine in the examined animals on average for all groups of sons was 308.2 ± 24.1 μmol / L, which exceeds the generally accepted values   of this indicator. However, taking into account age and sex and breed characteristics, taking into account data on the overall health of the animals examined, information on the ecological well-being of the breeding zone, the results can be considered as reference values   for healthy Holstein bulls in Western Siberia. It was shown that in the blood serum of the sons of some fathers, the creatinine content was 1.7 times higher (364.2 ± 52.7 μmol / L) than in the descendants of other manufacturers (p> 0.95). A group of half-siblings was found, which were characterized by a low hereditary predisposition to creatinine content. Discovered differences in the creatinine content in the blood serum of sons reflect the differentiation of bulls and indicate genetically determined features of the functioning of the homeostasis system. In this case, most likely, there is a different ability of descendants to adapt to environmental and climatic conditions.Изложены результаты исследований показателей азотистого обмена в сыворотке крови потомков четырех быков-производителей в возрасте 12–13 месяцев. Исследования проведены на юге Западной Сибири в ОАО «Ваганово» на популяции скота голштинской породы. Концентрация креатинина в пробах сыворотки крови сыновей была определена с помощью набора реактивов фирмы «Вектор-Бест» (Россия). В регионах разведения животных проводится постоянный мониторинг воды, почвы, кормов, органов и тканей животных. Установлено, что в районах, в которых разводились исследуемые породы, содержание макро- и микроэлементов не превышало ПДК. Уровень сывороточного креатинина у обследованных животных в среднем по всем группам сыновей составил 308,2±24,1 мкмоль/л, что превышает общепринятые значения данного показателя. Однако учитывая половозрастные и породные особенности, принимая во внимание данные о полном здоровье обследованных животных, сведения об экологическом благополучии зоны разведения, полученные результаты можно считать референсными значениями для здоровых быков голштинской породы в условиях Западной Сибири. Показано, что в сыворотке крови сыновей некоторых отцов содержание креатинина было в 1,7 раза выше (364,2±52,7 мкмоль/л), чем у потомков других производителей (p>0,95). Обнаружена группа полусибсов, которые отличались низкой наследственной предрасположенностью к содержанию креатинина. Обнаруженные различия по содержанию креатинина в сыворотке крови сыновей отражают дифференциацию быков-производителей и указывают на генетически детерминированные особенности функционирования системы гомеостаза. При этом, вероятнее всего, возникает и разная способность потомков адаптироваться к эколого-климатическим условиям

Stability of liquid bridges between coaxial equidimensional disks to axisymmetric finite perturbations: A review

This paper reviews the dynamics of breaking or oscillating axisymmetric liquid bridges, and estimates of the energy which is needed to break a liquid bridge. We consider a liquid bridge spanning two coaxial equal disks with sharp edges and held by surfacetension forces. The liquid volume is assumed to be conserved under perturbations, and the contact lines are pinned to the disk edges. The perturbations are finite and axisymmetric. An analysis is based on the one-dimensional models previously used in capillary jet theory and last several decades for study a liquid bridge dynamics. According to the scientific project JEREMI (Japanese and European Research Experiment on Marangoni Instabilities), the first stage of the space experiment on ISS will involve an isothermal liquid bridge with a gas blowing parallel to the axial direction of the bridge. The geometry corresponds to a cylindrical volume liquid bridge coaxially placed into an outer cylinder with solid walls. The gas enters the annular duct bounded by the outer cylinder and the internal system consisting of supporting vertical rods and the liquid bridge. Considering that the bridge is small (the rod's radii are 3 mm) and the gas velocity is typically (0.25 / 0.37) m/s, the perturbations cannot be considered small. Thus, one may assume that the amplitude of the liquid bridge perturbations is sufficiently large that departures from linearity must be considered. © Springer Science+Business Media B.V. 2012.SCOPUS: re.jinfo:eu-repo/semantics/publishe

МАКРО- И МИКРОЭЛЕМЕНТЫ В ПОЧВАХ И КОРМОВЫХ ТРАВАХ ПРИФЕРМЕРСКИХ ПОЛЕЙ БАРНАУЛЬСКОГО ПРИОБЬЯ

The authors highlight significant and relevant problem, which is seen as fulfilling people needs in environmentally safe plant, and animal production, which is rich in minerals. The paper points out farmlands closely located to industrial centres that pollute environment and require specific controlling measures. The authors explore and assess macro and microelements composition of soils and plant production from farmlands of agricultural enterprises located in the suburbs of Barnaul. The researchers investigated soils and hay of perennial grasses from by-farm fields of Barnaulskoe enterprise and Sibirskie bychki enterprise. Mixed samples of soil were received from 0-20 sm plough-layer whereas grass hay was applied from rolls. Agrochemical properties of soils were investigated by means of general and standard methods. The researchers explored total concentration of macro and microelements in the soil and ash by means of atomic emission spectrometry and grating spectrograph PGS-2, arc argon two-spool plasmotron and multi-channel analyzer of emission spectrums. The researchers measured concentration of macro- and microelements in the soil in acetate-ammoniacal buffer solution with рН 4,8 by means of atomic emission spectrometry. Accuracy control was carried out by means of applying corresponding standards. The research results has shown lack of agrogenic or technogenic pollution caused by heavy metals and feeding grasses on by-farm fields of livestock enterprises located in the suburbs of the industrial city. Otherwise, the researchers revealed the problem of feeding crops in these farmlands. This problem deals with lack of concentration of elements P, Ca, Co, Cu, Mg, Mn, Na and Zn in feeding crops. Low concentration of elements in plant production shows insufficient mineral concentration and agrochemical problem, which is depletion of minerals necessary for plants.Обеспечение населения экологически безопасной и минерально полноценной продукцией растениеводства и животноводства - актуальная проблема. Особого внимания и контроля требуют сельскохозяйственные угодья вблизи промышленных центров, загрязняющих окружающую среду разными веществами. С этой целью изучен и оценен макро- и микроэлементный состав почв и растительной продукции прифермских полей сельхозпредприятий вблизи города Барнаула. Объектами исследования служили почвы и сено многолетних сеяных злаковых трав с прифермских полей ОАО Племпредприятие «Барнаульское» и ОАО «Сибирские бычки». Смешанные пробы почв брали из слоя 0-20 см пахотного горизонта, а сена трав - из рулонов. Агрохимические свойства почв изучали стандартными методами. Валовое содержание макро- и микроэлементов в почвах и золе растений определяли методом атомно-эмиссионной спектрометрии с использованием дифракционного спектрографа PGS-2, дугового аргонового двухструйного плазмотрона, многоканального анализатора эмиссионных спектров. Концентрацию подвижной формы макро- и микроэлементов в почвах в ацетатно-аммонийном буферном растворе с рН 4,8 измеряли методом атомно-абсорбционной спектрометрии. Контроль точности измерений макро- и микроэлементов в почвах и растениях проводили с использованием соответствующих стандартных образцов. Результаты исследования показали отсутствие экологической проблемы агрогенного и техногенного загрязнения тяжелыми металлами почв и кормовых трав на прифермских полях животноводческих предприятий вблизи крупного промышленного центра. Напротив, выявлена биогеохимическая проблема дефицита в кормовых культурах на этих сельскохозяйственных угодьях таких эссенциальных макро- и микроэлементов, как P, Ca, Co, Cu, Mg, Mn, Na, Zn. Их низкое содержание в растительной продукции указывает на её недостаточную минеральную полноценность и свидетельствует о наличии агрохимической проблемы - истощения в почвах запасов их подвижной и доступной растениям формы

Direct observation of pH-induced coalescence of latex-stabilized bubbles using high-speed video imaging

The coalescence of pairs of 2 mm air bubbles grown in a dilute electrolyte solution containing a lightly cross-linked 380 nm diameter PEGMA-stabilized poly(2-vinylpyridine) (P2VP) latex was monitored using a high-speed video camera. The air bubbles were highly stable at pH 10 when coated with this latex, although coalescence could be induced by increasing the bubble volume when in contact. Conversely, coalescence was rapid when the bubbles were equilibrated at pH 2, since the latex undergoes a latex-to-microgel transition and the swollen microgel particles are no longer adsorbed at the air−water interface. Rapid coalescence was also observed for latex-coated bubbles equilibrated at pH 10 and then abruptly adjusted to pH 2. Time-dependent postrupture oscillations in the projected surface area of coalescing P2VP-coated bubble pairs were studied using a high-speed video camera in order to reinvestigate the rapid acid-induced catastrophic foam collapse previously reported [Dupin, D.; et al. J. Mater. Chem. 2008, 18, 545]. At pH 10, the P2VP latex particles adsorbed at the surface of coalescing bubbles reduce the oscillation frequency significantly. This is attributed to a close-packed latex monolayer, which increases the bubble stiffness and hence restricts surface deformation. The swollen P2VP microgel particles that are formed in acid also affected the coalescence dynamics. It was concluded that there was a high concentration of swollen microgel at the air−water interface, which created a localized, viscous surface gel layer that inhibited at least the first period of the surface area oscillation. Close comparison between latex-coated bubbles at pH 10 and those coated with 66 μm spherical glass beads indicated that the former system exhibits more elastic behavior. This was attributed to the compressibility of the latex monolayer on the bubble surface during coalescence. A comparable elastic response was observed for similar sized titania particles, suggesting that particle size is a significant factor in defining the interfacial elasticity of particle-coated bubble