Passage of Bolides Through the Atmosphere

Different fragmentation models are applied to a number of events, including the entry of TC3 2008 asteroid in order to reproduce existing observational data. Keywords meteoroid entry fragmentation modeling 1 Introduction Fragmentation is a very important phenomenon which occurs during the meteoroid entry into the atmosphere and adds more drastic effects than mere deceleration and ablation. Modeling of bolide fragmentation (100 106 kg in mass) may be divided into several approaches. Detail fitting of observational data (deceleration and/or light curves) allows the determination of some meteoroid parameters (ablation and shape-density coefficients, fragmentation points, amount of mass loss) (Ceplecha et al. 1993; Ceplecha and ReVelle 2005). Observational data with high accuracy are needed for the gross-fragmentation model (Ceplecha et al. 1993), which is used for the analysis of European and Desert bolide networks data. Hydrodynamical models, which describe the entry of the meteoroid including evolution of its material, are applied mainly for large bodies (>106 kg) (Boslough et al. 1994; Svetsov et al. 1995; Shuvalov and Artemieva 2002, and others). Numerous papers were devoted to the application of standard equations for large meteoroid entry in the attempts to reproduce dynamics and/or radiation for different bolides and to predict meteorite falls. These modeling efforts are often supplemented by different fragmentation models (Baldwin and Sheaffer, 1971; Borovi.ka et al. 1998; Artemieva and Shuvalov, 2001; Bland and Artemieva, 2006, and others). The fragmentation may occur in different ways. For example, few large fragments are formed. These pieces initially interact through their shock waves and then continue their flight independently. The progressive fragmentation model suggests that meteoroids are disrupted into fragments, which continue their flight as independent bodies and may be disrupted further. Similar models were suggested in numerous papers, beginning with Levin (1956) and initial interaction of fragments started to be taken into account after the paper by Passey and Melosh (1980). The progressive fragmentation model with lateral spreading of formed fragments is widely used (Artemieva and Shuvalov, 1996; Nemtchinov and Popova, 1997; Borovi.ka et al. 1998; Bland and Artemieva, 2006)

Content of the scope of the companies' business efficiency controlling

The peculiarities of the current economic conditions associated with significant sophistication and extension of linkages between individual systems and elements of the companies require the managers to improve the business parameters’ monitoring procedures

Modeling the accuracy in the process of mechanical treatment of worm-wheels of worm gears with a concave profile of the worm turn

Вперше теоретично доведено й експериментально підтверджено необхідність та доцільність підвищення точності механічної обробки черв’ячних коліс шляхом застосування нових черв’ячних фрез із поділеним на три частини по висоті профілем інструментальної рейки. Встановлено, що для підвищення точності механічної обробки черв’ячного колеса профіль інструментальної рейки черв’ячної фрези необхідно поділити на три частини по висоті, а кількість зубців фрези повинна дорівнювати 12. Отримано математичні моделі процесу механічної обробки черв’ячних коліс циліндричних черв’ячних передач з угнутим профілем витка черв’яка.For the first time it was theoretically proved and experimentally confirmed the necessity and expediency in increase of accuracy in mechanical treatment of worm-wheels using new worm hobs with a divided in three parts according to the height profile of a tool rack. It was stated that in order to increase the accuracy of mechanical treatment of a worm-wheel, the profile of a tool rack of a worm hob should be divided in three parts according to the height and the quantity of teeth of the hob should equal 12. We received mathematical models of the process of treatment of worm-wheels of cylindrical worm gears with concave profile of a worm turn. The object of the research included geometrical characteristics of a worm-wheel such as deviation of output circuit (left and right sides) of teeth of the worm-wheel Fα, μm; deviation of pitch (left and right sides) of teeth of the worm-wheel from nominal fPt, μm; accumulated error of a pitch (left and right sides) FP, μm; radial runout Fn, μm; deviation in tooth profile of a worm-wheel (left and right sides) ff , μm; diameter of a wheel cave Df, mm. We disclosed positive dependence in the process of mechanical treatment of a worm-wheel on the quantity of parts of profile division according to the height of tool rack of a worm hob N, which under other equal conditions with the increase of N there is a redistribution of allowance between passes and a change in the scheme of metal removal out of the caves between teeth of a wheel which is being cut. As a result the quantity of passes of the hob nпр decreases which leads to a decrease in a wheel’s tooth cut and in deviation of output circuit of the right and left sides of a tooth of a worm-wheel which increases the accuracy of treatment. Also we disclosed a considerable influence of the quantity of teeth of the worm hob on the deviation of the output circuit of a worm-wheel under mechanical treatment using tangential infeed. The increase of the number of racks increases the quantity of cuts which allows improving the accuracy of treatment. Moreover, the increase in number of racks leads to the increase of the coefficient of front overlap in machine engagement of a worm hob- blank. This allows decreasing irregularity in cutting, dynamic loading and increasing the accuracy of treatment. Due to the fact that the worm hob with a divided in three parts profile according to the height of a tool rack has located on the same helix teeth for the first, second and third passes with equal diameter of caves and different outer diameters, the treatment of a worm-wheel is carried out with one installation which improves the accuracy in treatment

Content of the scope of the companies' business efficiency controlling

The peculiarities of the current economic conditions associated with significant sophistication and extension of linkages between individual systems and elements of the companies require the managers to improve the business parameters’ monitoring procedures

Timeline as service of interactive training within discipline “History of computer facilities”

В статье приведен обзор сервисов для создания лент времени. Показаны примеры использования лент времени при изучении дисциплины история вычислительной техники.The review of services for creation of timeline is provided in article. Examples of use of timeline when studying discipline “History of computer facilities” are shown

Біблеїзми vs вульгаризми – барометр соціальної освіченості (Biblical expressions vs vulgarisms – barometer of social accomplishment)

Стаття має наметі дослідити конотативно-забарвлені лексичні одиниці – біблеїзми та вульгаризми – у перед виборчому дискурсі США. Біблеїзми та вульгаризми представляють собою семантичну опозицію та взаємовиключність сфер вживання. Разом з тим, саме передвиборчий дискурс США здатен продемонструвати стирання такого чіткого розділу сфер уживання даних лексичних одиниць. (The article deals with the research of connotatively charged lexical units in pre-election discourse of the USA. The connotatively charged lexical units to be considered are biblical expressions and vulgarisms. They present semantic opposition and have exclusive spheres of usage. This means that the sphere characterized by the usage of biblical expressions, for example, will never approve the usage of vulgarisms. Still the very pre-election discourse of the USA is capable to absorb both categories that is dictated by the very features of the discourse, its characteristics and modern tendencies to simplification and approaching to colloquial features. The aim of the article is to prove and to approve usage of the both connotatively charged lexical units (biblical expressions and vulgarisms) in the pre-election discourse of the USA. On the one hand, the first category (biblical expressions) shows addressant’s exclusive ability to control his speech and to present himself in the best light, to follow old traditions of the rhetoric speech which are badly needed for a theatrical strategy. And the second category (vulgarisms), vice versa, is to show lack of experience and self control. Still, the popularity of the pre-election discourse of the USA and contextual sense of the used lexical units may change such a rigid division and definition.

Determination Methods Of Defrosted Protein-vegetable Mixtures Parameters Development

The aim of the work is to develop methods of investigating the influence of semolina and extruded semolina on quality and quantity parameters of mixtures with milk-protein concentrates in a cycle of freezing-defrost that allows to substantiate resource-saving in semi-products manufacturing.Obtained results of changes of the quality of protein-vegetable mixtures after the effect of negative temperatures confirm cryo-protective properties of carbohydrates of products of wheat processing.There were studied methods of extracting proteins of whey for getting albumin mass and using in the composition of milk-protein concentrates. It was established, that adding collagen-containing ingredients in amount 0,4 % for intensifying thermal coagulation of whey proteins decreases the duration of precipitation to (55±2) and (40±2) min respectively depending on a type of raw material processing. There were studied both native whey and protein concentrate, obtained by the method of ultra-filtration with mass share of dry substances (16±2) %.The method of thermal analysis determined a cryoscopic temperature of sour-milk fatless cheese and also albumin mass, obtained using «Collagen pro 4402». The calculation method, based on cryoscopic temperature indices determined an amount of moisture, frozen out in milk-whey mixtures with wheat processing products. The presented information is enough for estimating traditional modes of freezing milk-protein concentrates objectively.The obtained results of the studies indicate the effectiveness of the offered methods for determining parameters of protein-vegetable mixtures after defrosting. Measurements of quality parameters may be used for correcting mass losses of concentrates effectively

Inversionless light amplification and optical switching controlled by state-dependent alignment of molecules

We propose a method to achieve amplification without population inversion by anisotropic molecules whose orientation by an external electric field is state-dependent. It is based on decoupling of the lower-state molecules from the resonant light while the excited ones remain emitting. The suitable class of molecules is discussed, the equation for the gain factor is derived, and the magnitude of the inversionless amplification is estimated for the typical experimental conditions. Such switching of the sample from absorbing to amplifying via transparent state is shown to be possible both with the aid of dc and ac control electric fields.Comment: AMS-LaTeX v1.2, 4 pages with 4 figure

Політичний дискус США як поле реалізації біблеїзмів «god», «bless»

Беручи за точку відліку місце біблеїзмів у політичному дискурсі США, у статті здійснюється аналіз частоти вживання лексичних одиниць «God» та «bless» у підготовленому та непідготовленому мовленні. Кількісні показники та аналіз семантичної складової слугують підтвердженням тенденції про зближення характеристик усного та письмового мовлення. (Taking into account biblical expressions in a political discourse of the USA the article gives the analysis of «God» and «bless» lexical units frequency in prepared and non-prepared speech. Quantity markers and semantic analysis prove the tendency of oral and written speech characteristics coming closer.