The origin of interparticle potential of electrorheological fluids

The particles of electrorheological fluids can be modelled as dielectric spheres (DS) immersed in a continuum dielectric. When an external field is applied, polarization charges are induced on the surfaces of the spheres and can be represented as point dipoles placed in the centres of the spheres. When the DSs are close to each other, the induced charge distributions are distorted by the electric field of the neighbouring DSs. This is the origin of the interaction potential between the DSs. The calculation of this energy is very time consuming, therefore, the DS model cannot be used in molecular simulations. In this paper, we show that the interaction between the point dipoles appropriately approximates the interaction of DSs. The polarizable point dipole model provides better results, but this model is not pair-wise additive, so it is not that practical in particle simulations.Comment: 10 pages, 5 figure

Monte Carlo simulation of the electrical properties of electrolytes adsorbed in charged slit-systems

We study the adsorption of primitive model electrolytes into a layered slit system using grand canonical Monte Carlo simulations. The slit system contains a series of charged membranes. The ions are forbidden from the membranes, while they are allowed to be adsorbed into the slits between the membranes. We focus on the electrical properties of the slit system. We show concentration, charge, electric field, and electrical potential profiles. We show that the potential difference between the slit system and the bulk phase is mainly due to the double layers formed at the boundaries of the slit system, but polarization of external slits also contributes to the potential drop. We demonstrate that the electrical work necessary to bring an ion into the slit system can be studied only if we simulate the slit together with the bulk phases in one single simulation cell.Comment: 11 pages, 8 figure

Ultrastructural studies of the mitochondriae in the striated muscles of birds with regard to experimental hypokinesis

Electron microscopic studies were carried out on the mitochrondria of the transversely striated muscles with regard to experimental hypokinesia. As compared to the central group the mitochondria of m. pectoralis thoracicus and the m. iliotibialis posterior in hypokinetic birds reveal marked changes. In filamentous and ovoid mitochondria, vacuoles can be observed which in some cases produced larger light formations with following disappearance of the cristae and destruction of mitochondria. Fat particles located at the poles of the altered mitochondria, sporadically occurring also laterally, presented another finding. The Z-lines of the sarcomere did not form a continuous line, but were somewhat shifted

Electron microscopical and histochemical studies on the transverse striated muscles of birds after prolonged hypokinesis

Studies of the gastrocnemius muscle were carried out in 4 month old cockerels of the laying hybrid after hypokinesis lasting 15 and 30 days. It was found that restricted movement resulted in dystrophic changes of myotibrils, enlargement of the sarcoplasmic reticulum and oedem of interfibrillar spaces. Histochemical studies revealed focuses of increased activity of non-specific esterase, decreased activity of dehydrogenase of lactic acid and a positive reaction of acid phosphatase

You never surf alone. Ubiquitous tracking of users' browsing habits

In the early age of the internet users enjoyed a large level of anonymity. At the time web pages were just hypertext documents; almost no personalisation of the user experience was o ered. The Web today has evolved as a world wide distributed system following specific architectural paradigms. On the web now, an enormous quantity of user generated data is shared and consumed by a network of applications and services, reasoning upon users expressed preferences and their social and physical connections. Advertising networks follow users' browsing habits while they surf the web, continuously collecting their traces and surfing patterns. We analyse how users tracking happens on the web by measuring their online footprint and estimating how quickly advertising networks are able to pro le users by their browsing habits

Spontaneous polarisation of the neutral interface for valence asymmetric coulombic systems

In this paper, we discuss the phenomenon of a spontaneous polarisation of a neutral hard planar interface for valence asymmetric coulombic systems. Within a field theoretical description, we account for the existence of non trivial charge density and electric potential profiles. The analysis of the phenomenon shows that the effect is related to combinatorics in relation with the existence of the two independent species cations and anions. This simple and basic feature is related to the quantum mechanical properties of the system. The theoretical results are compared with numerical simulations data and are shown to be in very good agreement, which a fortiori justifies our physical interpretation.Comment: 12 pages, 11 figure

PENAMPILAN REPRODUKSI SAPI POTONG LOKAL DI KECAMATAN BOLAANG KABUPATEN BOLAANG MONGONDOW

REPRODUCTIVE PERFORMANCE OF LOCAL BEEF COWS IN BOLAANG DISTRICT OF BOLAANG MONGONDOW REGENCY. This study aims to determine the reproductive performance of local beef cattle in Bolaang District, BolaangMongondow Regency. This study used local beef cattle owned by breeders who were taken as samples in several villages in Bolaang District, Bolaang Mongondow Regency. This study used a survey method to obtain primary and secondary data collection. Data analysis regarding the studied variables used descriptive analysis referring to the measurement of each variable. The results showed that service per conception was 1.38, conception rate was 70%, pregnancy period was 276.47 days, animal age of first calving was 32.022 months, and calving interval was 375.26 days. Based on these results of study, it can be concluded that the reproductive performance of local beef cattle in Bolaang district, Bolaang Mongondow regency was categorized into normal reproductive performance of local beef cattle. Key word: Reproduction, Local beef cow, Bolaang district, 

Technológiai Előretekintési Program

Az Országos Mûszaki Fejlesztési Bizottság döntése alapján 1998-ban átfogó elemzés kezdôdött Technoló- giai Elôretekintési Program (TEP) néven. A program célja, hogy a piaci és technológiai lehetôségek feltá- rásával hozzájáruljon a hosszú távú versenyképesség növeléséhez és ezen keresztül az életminôség javításá- hoz. A TEP a gazdasági, társadalmi folyamatok, a tudo- mány és technika eredményeinek elemzésével megje- löli azon kulcskérdéseket, döntési pontokat, amelyek meghatározzák az egyes szakmai területek illetve az ország jövôjét a következô 15-25 évben. Az Irányító Testület és a munkacsoportok elemezték a jelenlegi helyzetet, eltérô jövôképeket vázoltak fel, és a legked- vezôbbnek ítélt – de a mai feltételek mellett, tudatos, összehangolt erôfeszítések nélkül nem feltétlenül a leg- valószínûbb – jövôkép megvalósítását célzó ajánlásokat fogalmaztak meg. A legkedvezôbb jövôképbôl leve- zetett ajánlások tehát mindazoknak szólnak, akik köz- vetlenül vagy közvetve hatással lehetnek az egyes szakterületek vagy a magyar társadalom és gazdaság egészének jövôjére

Dielectric constant of the polarizable dipolar hard sphere fluid studied by Monte Carlo simulation and theories

A systematic Monte Carlo (MC) simulation and perturbation theoretical (PT) study is reported for the dielectric constant of the polarizable dipolar hard sphere (PDHS) fluid. We take the polarizability of the molecules into account in two different ways. In a continuum approach we place the permanent dipole of the molecule into a sphere of dielectric constant Ɛ∞ in the spirit of Onsager. The high frequency dielectric constant Ɛ∞ is calculated from the Clausius-Mosotti relation, while the dielectric constant of the polarizable fluid is obtained from the Kirkwood-Frohlich equation. In the molecular approach, the polarizability is built into the model on the molecular level, which makes the interactions non- pairwise additive. Here we use Wertheim’s renormalized PT method to calculate the induced dipole moment, while the dielectric constant is calculated from our recently introduced formula [22]. We also apply a series expansion for the dielectric constant both in the continuum and the molecular approach. These series expansions ensure a better agreement with simulation results. The agreement between our MC data and the PT results in the molecular approach is excellent for low to moderate dipole moments and polarizabilities. At stronger dipolar interactions ergodicity problems and anizotropic behaviour appear where simulation results become uncertain and the theoretical approach becomes invalid.Приведено результати систематичного вивчення методом Монте Карло (МК) та теорії збурень (ТЗ) діелектричної сталої рідини поляризаційних дипольних твердих сфер. Поляризація молекул враховується двома способами. У підході неперервного середовища постійний диполь молекули поміщається у сферу з діелектричною сталою Ɛ∞, так як це робиться Онзагером. Високочастотна діелектрична стала Ɛ∞ рахується зі співвідношення Клаузіса-Мозотті, тоді як діелектрична стала поляризаційної рідини отримується з рівняння Кірквуда-Фройліха. У молекулярному підході поляризація враховується на молекулярному рівні, внаслідок чого взаємодії не є парно адитивними. Для розрахунку індикованого дипольного моменту використовується ренормалізаційний метод ТЗ Вертхайма, а для діелектричної сталої використовується оригінальна формула [22]. Ми також застосовуємо групові розклади для діелектричної сталої в обох підходах. Групові розклади забезпечують кращу узгодженість з комп’ютерними результатами. Узгодженість між МК даними і результатами ТЗ є дуже доброю у діапазоні низьких та середніх дипольних моментів та поляризації. Для сильних дипольних взаємодій проявляються проблеми ергодичності та анізотропної поведінки і комп’ютерні дані стають сумнівними, а теоретичні результати – необгрунтованими