Phase behavior and interfacial properties of nonadditive mixtures of Onsager rods

Within a second virial theory, we study bulk phase diagrams as well as the free planar isotropic-nematic interface of binary mixtures of nonadditive thin and thick hard rods. For species of the same type the excluded volume is determined only by the dimensions of the particles, whereas for dissimilar ones it is taken to be larger or smaller than that, giving rise to a nonadditivity that can be positive or negative. We argue that such a nonadditivity can result from modelling of soft interactions as effective hard-core interactions. The nonadditivity enhances or reduces the fractionation at isotropic-nematic ($IN$) coexistence and may induce or suppress a demixing of the high-density nematic phase into two nematic phases of different composition ($N_1$ and $N_2$), depending on whether the nonadditivity is positive or negative. The interfacial tension between co-existing isotropic and nematic phases show an increase with increasing fractionation at the $IN$ interface, and complete wetting of the $IN_2$ interface by the $N_1$ phase upon approach of the triple point coexistence. In all explored cases bulk and interfacial properties of the nonadditive mixtures exhibit a striking and quite unexpected similarity with the properties of additive mixtures of different diameter ratio.Comment: 12 pages, revised version, submitted to JC

Design and realisation of a MZI type polymer based high speed EO-modulator

We designed a 20 GHz Mach Zehnder interferometric EO-modulator based on a new developed polyesterimide. Measurements show a V/sub /spl pi// of 7.5 V, an insertion loss of 11 dB and an extinction ratio exceeding 20 dB for an interaction length of 2 cm

Natural hybridization between Populus nigra L. and P. x canadensis Moench. Hybrid offspring competes for niches along the Rhine river in the Netherlands

Black poplar (Populus nigra L.) is a major species for European riparian forests but its abundance has decreased over the decades due to human influences. For restoration of floodplain woodlands, the remaining black poplar stands may act as source population. A potential problem is that P. nigra and Populus deltoides have contributed to many interspecific hybrids, which have been planted in large numbers. As these Populus x canadensis clones have the possibility to intercross with wild P. nigra trees, their offspring could establish themselves along European rivers. In this study, we have sampled 44 poplar seedlings and young trees that occurred spontaneously along the Rhine river and its tributaries in the Netherlands. Along these rivers, only a few native P. nigra L. populations exist in combination with many planted cultivated P. x canadensis trees. By comparison to reference material from P. nigra, P. deltoides and P. x canadensis, species-specific AFLP bands and microsatellite alleles indicated that nearly half of the sampled trees were not pure P. nigra but progeny of natural hybridisation that had colonised the Rhine river banks. The posterior probability method as implemented in NewHybrids using microsatellite data was the superior method in establishing the most likely parentage. The results of this study indicate that offspring of hybrid cultivated poplars compete for the same ecological niche as native black poplars

Structuring for serendipity: family wealth creation, farmer autonomy and the pursuit of security in an uncertain Australian countryside

The social and economic particularities of family farms have captured researchers’ attention for many years; but rural scholarship still lacks a clear, analytical sense of how and why family farms are organised in the ways that they are. This thesis critically examines the internal logics underpinning the socio-economic organisation of Australian farms. It adopts Johnsen’s (2003) conceptualisation of farm enterprises as three-way coalitions between farm businesses, farm households and the respective property holdings. Changes to the Australian agricultural property regime are used as the lens through which to observe how the organisational logics of farm enterprises are recalibrated in response to environmental policy reforms; specifically, the separation of land and water titles. Despite the obvious economic significance of separating land and water titles, the impacts on farm organisation remain under-researched. Hence, this thesis uniquely brings together scholarship on family farming with that of water reforms. A qualitative research method – farm life history – is used to generate narratives of the development of 40 farms in Victoria, Australia. Twenty-one of these are from an irrigation district where land and water titles have been separated, and nineteen from a dry land region unaffected by the reforms. The interpretive chapters comprise an analysis of the ways in which the ownership configurations of farm businesses, land and water assets embody farmers’ aspirations for building wealth and maintaining autonomy. These aspirations are jointly articulated in the concept of ‘structuring for serendipity’, which elevates the notions of risk, uncertainty and security as critical drivers shaping farm-level responses to contemporary conditions. The thesis concludes that the organisational forms observed within the Australian agricultural sector ultimately represent farmers’ pursuit of a sense of security in a constantly changing and uncertain countryside

Inhibitory Deficits in reading disability depend on subtype: guessers but not spellers

In this study, children with the guessing subtype of dyslexia (who read fast and inaccurately) were compared with children with the spelling subtype (who read slowly and accurately) on three aspects of executive functioning (EF): response inhibition, susceptibility to interference from irrelevant information, and planning. It was found that guessers were impaired in their ability to inhibit inappropriate responding on all tasks used to assess EF (the stop signal task, the Stroop task, and the Tower of London task). This raises the question of whether the specific reading disorder of guessers may be linked to the same executive deficits which underlie ADHD. In order to unite a fast/inaccurate reading style with executive deficiencies, an attempt is made to incorporate the concept of executive control into models of lexical activation

Transient nucleation driven by solvent evaporation

We theoretically investigate homogeneous crystal nucleation in a solution containing a solute and a volatile solvent. The solvent evaporates from the solution, thereby continuously increasing the concentration of the solute. We view it as an idealized model for the far-out-of-equilibrium conditions present during the liquid-state manufacturing of organic electronic devices. Our model is based on classical nucleation theory, taking the solvent to be a source of the transient conditions in which the solute drops out of solution. Other than that, the solvent is not directly involved in the nucleation process itself. We approximately solve the kinetic master equations using a combination of Laplace transforms and singular perturbation theory, providing an analytical expression for the nucleation flux, predicting that (i) the nucleation flux lags slightly behind a commonly used quasi-steady-state approximation, an effect that is governed by two counteracting effects originating from the solvent evaporation: while a faster evaporation rate results in an increasingly larger influence of the lag time on the nucleation flux, this lag time itself we find to decrease with increasing evaporation rate, (ii) the nucleation flux and the quasi-steady-state nucleation flux are never identical, except trivially in the stationary limit and (iii) the initial induction period of the nucleation flux, which we characterize with a generalized induction time, decreases weakly with the evaporation rate. This indicates that the relevant time scale for nucleation also decreases with increasing evaporation rate. Our analytical theory compares favorably with results from numerical evaluation of the governing kinetic equations

До питання про культурну атрибутацію шару ранньозалізного віку на городищі Теребовля І

У статті на основі досліджень І.Русанової, Р.Миська та М.Ягодинської проведено атрибутацію культурного шару ранньозалізного віку на городищі літописної Теребовлі. Висловлюється припущення, що перші оборонні споруди на городищі Теребовля І «Замкова Гора», вал 3-ій та 4-ий городища збудовані носіями висоцької культури у ІХ-VIII ст. до н.е

RNA topology remolds electrostatic stabilization of viruses

Simple RNA viruses efficiently encapsulate their genome into a nano-sized protein shell-the capsid. Spontaneous co-assembly of the genome and the capsid proteins is driven predominantly by electrostatic interactions between the negatively charged RNA and the positively charged inner capsid wall. Using field theoretic formulation we show that the inherently branched RNA secondary structure allows viruses to {\sl maximize} the amount of encapsulated genome and make assembly more efficient, allowing viral RNAs to out-compete cellular RNAs during replication in infected host cell

Перспективы развития рынка огнеупоров для сталеплавильного комплекса Украины

Основной эффект в снижении удельного расхода огнеупоров достигается за счет создания новых видов огнеупорных материалов, технологических усовершенствований при их производстве, развития новых конструкционных схем футеровки технологических агрегатов, совершенствования условий эксплуатации и ремонта футеровки и т. п. На металлургических предприятиях Украины в этом плане в последние годы наблюдается достаточно устойчивая тенденция повышения стойкости футеровки конвертеров, дуговых сталеплавильных печей, сталеразливочных и промежуточных ковшей.Основний ефект у зниженні питомої витрати вогнетривів досягається за рахунок створення нових видів вогнетривких матеріалів, технологічних удосконалень при їх виробництві, розвитку нових конструкційних схем футерівки технологічних агрегатів, удосконалення умов експлуатації та ремонту футерівки тощо. На металургійних підприємствах України в цьому плані в останні роки спостерігається досить стійка тенденція підвищення стійкості футерівки конвертерів, дуго- вих сталеплавильних печей, сталерозливних і проміжних ковшів.The main effect in reducing the specific consumption of refractories is reached by the creation of new types of refractory materials, technological improvements in their production, development of new structural patterns lining process units, improved operating conditions and lining repair, etc. In this regard, at Ukrainian metallurgical enterprises in recent years there has been quite stable tendency to increase the resistance of lining converters, electric arc steel furnaces, steel-teeming and tundish ladles