Finite-Weber-Number Motions of Bubbles Through a Nearly Inviscid Liquid

A method is described for computing the motion of bubbles through a liquid under conditions of large Reynolds and finite Weber numbers. Ellipsoidal harmonics are used to approximate the shapes of the bubbles and the flow induced by the bubbles, and a method of summing flows induced by groups of bubbles, using a fast multipole expansion technique is employed so that the computational cost increases only linearly with the number of bubbles. Several problems involving one, two and many bubbles are examined using the method. In particular, it is shown that two bubbles moving towards each other in an impurity-free, inviscid liquid touch each other in a finite time. Conditions for the bubbles to bounce in the presence of non-hydrodynamic forces and the time for bounce when these conditions are satisfied are determined. The added mass and viscous drag coefficients and aspect ratio of bubbles are determined as a function of bubble volume fraction and Weber number

Angle-dependent magnetoresistance in the weakly incoherent interlayer transport regime

We present comparative studies of the orientation effect of a strong magnetic field on the interlayer resistance of $\alpha$-(BEDT-TTF)$_2$KHg(SCN)$_4$ samples characterized by different crystal quality. We find striking differences in their behavior which is attributed to the breakdown of the coherent charge transport across the layers in the lower quality sample. In the latter case, the nonoscillating magnetoresistance background is essentially a function of only the out-of-plane field component, in contradiction to the existing theory.Comment: 4 pges, 3 figure

Staggered Spin Order of Localized pi-electrons in the Insulating State of the Organic Conductor kappa-BETS)2Mn[N(CN)2]3

Magnetic properties of the conduction pi-electron system of kappa-BETS)2Mn[N(CN)2]3 have been probed using 13C NMR. At ambient pressure, the metal-insulator transition observed in the resistivity measurements below T~23K is shown to be accompanied by ordering of the pi-spins in a long-range staggered structure. As the metal-insulator transition is suppressed by applying a small pressure of ~0.5 kbar, the pi-spin system maintains the properties of the metallic state down to 5K.Comment: 13 pages, 4 figure

Мікроскопічна будова прямої кишки свійської качки

As a rule, researchers pay less attention to the features of the large intestine than to the small intestine. The purpose of the study was to determine the features of the microscopic structure of the rectum of ducks during the first year of the postnatal period of ontogenesis. For histological examinations, the material was selected from Ukrainian white-breasted ducks of 9 age groups: 1-, 3-, 7-, 14-, 21-day-old, 1-, 2-, 6-month-old and 1-year-old. Morphometric parameters of microstructures were set on cross sections of the midgut. The general change pattern in the morphometric parameters of the microstructures of the rectum of ducks was their increase, which was asynchronous and uneven. There was observed an active intestinal morphogenesis continued, as evidenced by the process of formation of villi and crypts in the group of 1-3-day-old ducks. The most intensive morphometric parameters of the rectum changed in the first month of the postnatal period of ontogenesis, during which – in the first week. In the first week, first and second month of life of ducks, the wall thickness of the rectum increased by 93.1, respectively; 199.5 and 20.4 %, the thickness of the mucous membrane – 81.0; 167.1 and 19.5 %, the thickness of the muscular membrane – by 126.1; 285.3 and 22.7 %, the height of the villi – by 113.2; 208.7 and 7.2 %, the width of the villi – by 84.7; 70.9 and 12.5 %, their surface area – by 293.8; 427.6 and 20.6 %, the depth of the crypt – by 85.1; 49.9 and 52.3 %, muscle plate thickness – by 254.0; 750.8 and 15.0 %. The most stable indicators of the rectum during the first year of the postnatal period of ontogenesis were the density of villi and crypts, the number of which after 7 days of age had no significant difference compared to that of a younger age. The indicates of adult birds morphometric parameters of the rectum of ducks corresponded at different ages: in 1-year-old – the thickness of the serous membrane and the density of villi; at 6 months – the diameter of the intestine, the surface area of the villi; at 2 months of age – the thickness of the wall and its mucous membrane, the width of the villi, the depth of the crypt; at 1 month – the thickness of the muscular membrane and plate, the height of the villi, the epithelium of the villi and crypt; at 3 days of age – the density of crypts; at 1 day of age – the width of the crypt.Метою роботи було визначити особливості мікроскопічної будови прямої кишки качок упродовж першого року постнатального періоду онтогенезу. Для гістологічних досліджень матеріал було відібрано від качок української білогрудої породи 9 вікових груп: 1-, 3-, 7-, 14-, 21-добового, 1-, 2-, 6-місячного і 1-річного віку. Морфометричні параметри мікроструктур встановлювали на поперечних зрізах середньої ділянки кишки. Загальною закономірністю змін морфометричних показників мікроструктур прямої кишки качок було їх збільшення, яке мало асинхронний і нерівномірний характер. У качок 1–3-добового віку продовжувався активний морфогенез кишечнику, про що свідчив процес утворення ворсинок і крипт. Найбільш інтенсивно морфометричні показники прямої кишки змінювались у перший місяць постнатального періоду онтогенезу, упродовж якого – в перший тиждень. У перший тиждень, перший і другий місяць життя качок товщина стінки прямої кишки збільшилась відповідно на 93,1; 199,5 і 20,4 %, товщина слизової оболонки – на 81,0; 167,1 і 19,5 %, товщина м’язової оболонки – на 126,1; 285,3 і 22,7 %, висота ворсинок – на 113,2; 208,7 і 7,2 %, ширина ворсинок – на 84,7; 70,9 і 12,5 %, площа їхньої поверхні – на 293,8; 427,6 і 20,6 %, глибина крипт – на 85,1; 49,9 і 52,3 %, товщина м’язової пластинки – на 254,0; 750,8 і 15,0 %. Найбільш стабільними показниками прямої кишки упродовж першого року постнатального періоду онтогенезу були щільність ворсинок і крипт, кількість яких після 7-добового віку не мала достовірної відмінності порівняно з таким меншого віку. Значенням дорослої птиці морфометричні показники прямої кишки качок відповідали в різному віці: в 1-річному – товщина серозної оболонки і щільність ворсинок; в 6-місячному – діаметр кишки, площа поверхні ворсинок; в 2-місячному віці – товщина стінки і її слизової оболонки, ширина ворсинок, глибина крипт; в 1-місячному – товщина м’язової оболонки і пластинки, висота ворсинок, епітелію ворсинок і крипт; у 3-добовому віці – щільність крипт; в 1-добовому віці – ширина крипт

Clean Diesel Engine Component Improvement Program Diesel Truck Thermoelectric Generator

Hi-Z Technology, Inc. (Hi-Z) is currently developing four different auxiliary generator designs that are used to convert a portion (5 to 20%) of the waste heat from vehicle engines exhaust directly to electricity. The four designs range from 200 Watts to 10 kW. The furthest along is the 1 kW Diesel Truck Thermoelectric Generator (DTTEG) for heavy duty Class 8 Diesel trucks, which, under this program, has been subjected to 543,000 equivalent miles of bouncing and jarring on PACCARâs test track. Test experience on an earlier version of the DTTEG on the same track showed the need for design modifications incorporated in DTTEG Mod 2, such as a heavy duty shock mounting system and reinforcement of the electrical leads mounting system, the thermocouple mounting system and the thermoelectric module restraints. The conclusion of the 543,000 mile test also pointed the way for an upgrading to heavy duty hose or flex connections for the internal coolant connections for the TEG, and consideration of a separate lower temperature cooling loop with its own radiator. Fuel savings of up to $750 per year and a three to five year payback are believed to be possible with the 5 % efficiency modules. The economics are expected to improve considerably to approach a two year payback when the 5 kW to 10 kW generators make it to the market in a few years with a higher efficiency (20%) thermoelectric module system called Quantum Wells, which are currently under development by Hi-Z. Ultimately, as automation takes over to reduce material and labor costs in the high volume production of QW modules, a one year payback for the 5 kW to10 kW generator appears possible. This was one of the stated goals at the beginning of the project. At some future point in time, with the DTTEG becoming standard equipment on all trucks and automobiles, fuel savings from the 25% conversion of exhaust heat to useable electricity nationwide equates to a 10% reduction in the 12 to 15 million barrels per day of imported oil, that much less air pollution, and an equivalent reduction in the trade deficit, which is expected to lower the inflation rate

Clean Diesel Engine Component Improvement Program Diesel Truck Thermoelectric Generator

Hi-Z Technology, Inc. (Hi-Z) is currently developing four different auxiliary generator designs that are used to convert a portion (5 to 20%) of the waste heat from vehicle engines exhaust directly to electricity. The four designs range from 200 Watts to 10 kW. The furthest along is the 1 kW Diesel Truck Thermoelectric Generator (DTTEG) for heavy duty Class 8 Diesel trucks, which, under this program, has been subjected to 543,000 equivalent miles of bouncing and jarring on PACCARâs test track. Test experience on an earlier version of the DTTEG on the same track showed the need for design modifications incorporated in DTTEG Mod 2, such as a heavy duty shock mounting system and reinforcement of the electrical leads mounting system, the thermocouple mounting system and the thermoelectric module restraints. The conclusion of the 543,000 mile test also pointed the way for an upgrading to heavy duty hose or flex connections for the internal coolant connections for the TEG, and consideration of a separate lower temperature cooling loop with its own radiator. Fuel savings of up to $750 per year and a three to five year payback are believed to be possible with the 5 % efficiency modules. The economics are expected to improve considerably to approach a two year payback when the 5 kW to 10 kW generators make it to the market in a few years with a higher efficiency (20%) thermoelectric module system called Quantum Wells, which are currently under development by Hi-Z. Ultimately, as automation takes over to reduce material and labor costs in the high volume production of QW modules, a one year payback for the 5 kW to10 kW generator appears possible. This was one of the stated goals at the beginning of the project. At some future point in time, with the DTTEG becoming standard equipment on all trucks and automobiles, fuel savings from the 25% conversion of exhaust heat to useable electricity nationwide equates to a 10% reduction in the 12 to 15 million barrels per day of imported oil, that much less air pollution, and an equivalent reduction in the trade deficit, which is expected to lower the inflation rate

Substitution Effect by Deuterated Donors on Superconductivity in κ\kappa-(BEDT-TTF)2_2Cu[N(CN)2_2]Br

We investigate the superconductivity in the deuterated BEDT-TTF molecular substitution system $\kappa$-[(h8-BEDT-TTF)$_{1-x}$(d8-BEDT-TTF)$_x$]$_2$Cu[N(CN)$_2$]Br, where h8 and d8 denote fully hydrogenated and deuterated molecules, respectively. Systematic and wide range ($x$ = 0 -- 1) substitution can control chemical pressure finely near the Mott boundary, which results in the modification of the superconductivity. After cooling slowly, the increase of $T_{\textrm{c}}$ observed up to $x \sim$ 0.1 is evidently caused by the chemical pressure effect. Neither reduction of $T_{\textrm{c}}$ nor suppression of superconducting volume fraction is found below $x \sim$ 0.5. This demonstrates that the effect of disorder by substitution is negligible in the present system. With further increase of $x$, both $T_{\textrm{c}}$ and superconducting volume fraction start to decrease toward the values in $x$ = 1.Comment: J. Phys. Soc. Jp

Fullerene Black: Relationship between Catalytic Activity in n-alkanes Dehydrocyclization and Reactivity in Oxidation, Bromination and Hydrogenolysis

The reactivity of fullerene black in oxidation (by air oxygen or ions MnO4–or Cr2O7 2– in solution), bromination (by Br2 or (C4H9)4NBr3) and hydrogenolysis (without hydrogenation catalyst) are studied. The dehydrocyclization of n-alkanes over fullerene black is realized via the monofunctional mechanism, i.e. the dehydrogenation and cyclization stages proceed on the same catalytic center. The addition of alumina to the catalyst transforms dehydrocyclization mechanism to bifunctional one, when fullerene black acts as dehydrogenation agent. Reactivity studies and ESR spectroscopy data for initial and annealed fullerene black show the presence in fullerene black structure of both non-conjugated multiple and dangling bonds. Nonconjugated bonds determine catalytic activity and reactivity of fullerene black. They are localized in amorphous part of fullerene black. Technological aspects of fullerene black as alkanes dehydrocyclization catalyst are discussed

Impurity Effect on Superconducting Properties in Molecular Substituted Organic Superconductor κ\kappa-(ET)2_2Cu(NCS)2_2

We report an impurity effect in the organic superconductor $\kappa$-(ET)$_2$Cu(NCS)$_2$ by substitution of the ET molecule with an analogue, bis(methyleneditio)tetrathiafulvalene (MT). The superconducting transition temperature decreases with increasing substitution. The in-plane magnetic penetration depth is enhanced with substitution, which is quantitatively attributed to the decrease in the in-plane mean free path. The enhancement of the penetration depth can also explain the reduction of the effective pinning in terms of the condensation energy.Comment: 4 pages, submitted to J. Phys. Soc. Jp