1,435 research outputs found
THIN FLUID FILM SQUEEZED WITH INERTIA BETWEEN 2 PARALLEL PLANE SURFACES
No full textThe present study is concerned with estimating the inertial effects on the draining of thin fluid layer between two parallel plane boundaries. In particular, we consider the case in which an initially stationary object with a circular plane lower surface begins suddenly moving under the action of a constant applied force toward a parallel plane wall when the inertia of the object and that of the intervening fluid in the gap are not negligible. The method of solution is a matched asymptotic expansion involving characterization of the solution by different characteristic time scales in different parts of the solution domain in the limit of small but finite Reynolds number based on the gap height. The asymptotic solution is presented for the time-dependent motion of the object and the fluid in the thin film including a proper description of the effects of both the inertia of the object and the inertia of the fluid
Maria Helena d'Eça Leal
No full textA minha homenagem a Maria Helena d'Eça Leal (na fotografia com Luís Filipe Costa), numa das capas mais bonitas dos meus livros. De uma entrevista de Clarisse Guerra (CG) a Luís Garlito (LG) (Arquivo da RTP AHD 14915), retiro o seguinte diálogo: CG: recordo-me que fui estagiar com a Maria Helena d’Eça Leal, que já aqui esteve neste programa. LG: E está, continua de facto a ser a voz do nosso indicativo [...]. CG: Fui estagiar com ela, porque sempre que entrava um locutor novo... Outros..
NONLINEAR EFFECTS IN THE DYNAMICS OF SHAPE AND VOLUME OSCILLATIONS FOR A GAS BUBBLE IN AN EXTERNAL FLOW
No full textThis paper considers the dynamics of a gas bubble in response to either a pressure pulse or a pressure step at t = 0, both in the presence and absence of a mean flow. Our work utilizes small-deformation, domain perturbation analysis carried to second and higher order in the amplitude of deformation, epsilon. In the absence of a mean flow, our analysis of the small deformation problem for an initial impulsive perturbation of the bubble volume and shape is closely related to recently published work by Longuet-Higgins on the time-dependent oscillations of an initially deformed bubble in a quiescent fluid. However, in the presence of a mean flow which deforms the bubble, the bubble response to pressure changes is more complex. Specifically, the present analysis identifies a number of different mechanisms for resonant interaction between shape deformation modes and the volume or radial breathing mode of oscillation. This includes not only a fundamental change in the resonant interactions at O(epsilon2)- where resonant interaction is also found in the absence of mean flow - but resonant interactions also at the level of O(epsilon3/2) which are not present without the mean flow. On the other hand, the bubble dynamics in response to a step change in the pressure distribution in a quiescent fluid exhibits similar resonant interactions at O(epsilon2) to those obtained for a pressure pulse in the presence of mean flow because the bubble oscillates around a non-spherical steady-state shape owing to the non-uniform pressure distribution on the bubble surface in both the cases
HYDRODYNAMIC INTERACTION OF A SMALL FLUID PARTICLE AND A SPHERICAL DROP IN LOW-REYNOLDS NUMBER FLOW
No full textThe present study is concerned with estimating the hydrodynamic interactions between a small droplet and a much larger fluid drop when both drops are translating through an otherwise quiescent fluid. The method of solution is a matched asymptotic expansion involving resolution of the local undisturbed flow produced by the motion of the large drop into component flows that provide the far-field boundary conditions for calculating the disturbance flows produced by the small droplet. In the limit of very small size ratio, the surface of the large drop appears as locally planar. The theory yields a complete trajectory equation including a proper description of the effect of hydrodynamic interactions between the two neighboring drops. The trajectory of the small droplet on approaching the large drop does not deviate significantly from the streamlines of the undisturbed flow until it comes within range of the hydrodynamic repulsion from the surface of the large drop. The magnitude of hydrodynamic repulsion becomes weaker as the viscosity of the droplet is reduced, and this effect is a strong function of the separation distance from the surface of the large drop
Hydrodynamic interaction between spheres coated with deformable thin liquid films
No full textIn this article, we considered the hydrodynamic interaction between two unequal spheres coated with thin deformable liquids in the asymptotic lubrication regime. This problem is a prototype model for drop coalescence through the so-called "film drainage" mechanism, in which the hydrodynamic contribution comes dominantly from the lubrication region apart from the van der Waals interaction force. First, a general formulation was derived for two unequal coated spheres that experienced a head-to-head collision at a very close proximity. The resulting set of the evolution equations for the deforming film shapes and stress distributions was solved numerically. The film shapes and hydrodynamic interaction forces were determined as functions of the separation distance, film thickness, viscosity ratios, and capillary numbers. The results show that as the two spheres approach each other, the films begin to flatten and eventually to form negative curvature (or a broad dimple) at their forehead areas in which high lubrication pressure is formed. The dimple formation occurs earlier as the capillary number increases. For large capillary numbers, the film liquids are drained out from their forehead areas and the coated liquid films rupture before the two films "touch" each other. Meanwhile, for small capillary numbers, the gap liquid is drained out first and the two liquid films eventually coalesce. (C) 2002 Elsevier Science (USA).This paper was accomplished with a research fund, “Support for Faculty
Research Abroad,” granted to Professor Seung-ManYang by theKorea Research
Foundation
Analysis of SIA „LG Electronics Latvia” Marketing Communications
No full textBakalaura darba tēma ir „SIA „LG Electronics Latvia” mārketinga komunikāciju analīze”. Bakalaura darba mērķis ir, pamatojoties uz mārketinga teorētisko avotu analīzi, izpētīt SIA „LG Electronics Latvia” veidoto mārketinga komunikāciju efektivitāti, kā arī izstrādāt priekšlikumus tās uzlabošanai.
Darba gaitā autors izmanto dažādas informācijas apkopošanas un analīzes metodes. Teorētiskās daļas veidošanai darba autors izmantoja literatūras referatīvās analīzes metodi. Informācijas iegūšanai par SIA „LG Electronics Latvia” tika izmantoti autora personīgās darba pieredzes laikā izdarītie novērojumi, kā arī tika izanalizētas uzņēmuma reklāmas, sabiedriskās saskares un citi informācijas avoti. Pētījuma daļā darba autors izstrādāja anketu ar mērķi noskaidrot sabiedrības domas par SIA „LG Electronics Latvia” veiktajiem mārketinga komunikācijas pasākumiem. Aptaujas iegūtos rezultātus autors apkopoja un veica to analīzi.
Darba kopējais apjoms, neieskaitot pielikumus, ir 67 lapaspuses. Darbā ir iekļauti 18 attēli, 3 tabulas, 3 pielikumi. Izmantotās literatūras avotu saraksts satur 18 avotus.The subject of the bachelor paper is “Analysis of the Marketing Communications of the LG Electronics Latvia Ltd”. The goal of the study is to investigate efficiency of LG Electronics Latvia Ltd marketing communications by applying a method of theoretical sources analysis and to develop proposals for its enhancement.
Various methods of information gathering and analysis have been applied by the author. For the development of the theoretical part, the author used a method of the publications analysis. For acquiring of the information about the LG Electronics Latvia Ltd, the author used his own observations on the enterprise that have been based on his earlier working experience within the company. Moreover, advertisements, promotions, public communication and other materials of the company have been analysed. For the research part of the bachelor work, the author elaborated a questionnaire - in order to clarify a public opinion on the marketing communication measures performed by the LG Electronics Latvia Ltd. The obtained date were compiled and analysed.
The total volumes of the bachelor paper, excluding the annex, are 67 pages. The paper also includes 18 figures, 3 tables, 3 annexes. The list of used literature comprises 18 reference items
Analisis Penjualan Lemari Es Merek Lg Pada PT. Lg Electronics Indonesia Cabang Pekanbaru
No full text: PT. LG Electronics Indonesia Branch of Pekanbaru is one trading company that sells a wide range of electronic products including Refrigerator. This study aims to: (1). Knowing the sales made by the management of PT. LG Electronics Indonesia Branch of Pekanbaru. (2). Knowing the factors that leads failure to achieve sales targets Refrigerator Brand LG At PT. LG Electronics Indonesia Branch of Pekanbaru. The population in this study is the whole of the object that is the entire consumer Refrigerator LG brand in the PT. LG Electronics Indonesia Pekanbaru Branch in 2013 as many as 8563 people. Because of the limitations of the author, then a swab which is considered to represent the customer as many as 100 people with slovin formula. Data analysis was performed using descriptive analysis method. The variables used are product, price, and promotion. Based on the results obtained, not the achievement of sales targets Refrigerator LG brand in the PT. LG Electronics Indonesia Branch Pekanbaru because the products offered have not been fully in accordance with the wishes and expectations of consumers, the price offered is not fully in accordance with the general economic conditions, as well as the promotion is not maximized
Dilemma frumarkernorum Leal, 2008, new species
No full textDilemma frumarkernorum new species (Figures 1–33, 58) Diagnosis. Shell with sculpture of coarse growth lines; escutcheon not well separated from remainder of shell; foot filiform; byssus relatively thick, robust; siphonal cowl of moderate size; siphonal tentacles arranged around entire incurrent siphonal opening; septal ostia arranged to define three pairs of line segments deployed around byssal opening, roughly delineating a hexagon; siphonal ostia distributed as follows: three anterior, four median, and four posterior. Description. SHELL (Figures 1–29, 33): Apparently nacreous internally, thin, equivalve (except for slight anteroposterior overlap at umbo), inequilateral, strongly compressed in anteroposterior direction, cardioid in lateral outline. Large byssal gap present in anteroventral position, on central portion of anterior shell surface. Shell sculpture consisting of coarse growth lines, with well-developed carina separating anterior from posterior shell regions. Carina sometimes set by a constriction that resembles a “pinched” line parallel to main shell outline. Umbones (Figure 26, U) projecting dorsally, located in anterior position. Umbonal cavity, large, spacious. Hinge with subtriangular, cardinal-like tooth (Figure 26, CT) in each valve, tooth in left valve with cleft distal extremity and more developed than that in right. Corresponding sockets (Figure 26, HS) present in each valve, that in right valve deeper than that in left valve. Posterior lateral tooth elongate, about 1 / 10 shell height, low, present on right valve only (Figures 25, 26, 27, LAT) interlocking with notched depression on left valve (Figure 27, LG). Ligament (Figures 25, 26, 27, LI) external, sunken; inner ligamental layer (Figure 28, IL) in part white, hard, possibly calcified (Figure 28, CIL); outer ligamental layer (Figure 28, OL) brown, with dorsal periostracum adhering to outer layer. Anterior adductor muscle scar (Figures 25, 26, 29, AAS) located on projection close to margin of valve, dorsal to byssal gap. Posterior adductor muscle scar (Figure 25, PAS) about same size as anterior adductor scar. Anterior byssal retractor scar (Figure 26, 29, ABS) small, relatively deep, situated on internal entrance to umbonal cavity. Posterior byssal retractor scar (Figure 25, PBS) larger than posterior adductor scar, elongate. Pallial line (Figures 25, 29, PAL) continuous, strong. Lunule absent. Escutcheon relatively poorly defined, not separated by a prominent groove, but distinguishable from remainder of shell by slightly smoother texture and commarginal band of lighter color. In specimens examined, shell color ranging from dull light-brown to olive-brown, sometimes suffused with peach-orange, usually on posteroventral part of valves. Periostracum light-brown, laid in coarse commarginal lamellae, mostly flaking in live-collected specimens. Macroanatomy. MANTLE MARGIN AND SIPHONS: Mantle margins fused (Figure 31, FM) leaving two siphonal openings (Figures 30, 32, 33, ES, IS) and byssal gape (Figure 31, BGA). Byssal gape circular to elliptical. Siphonal apertures separate; siphonal area sometimes colorful in freshly preserved animals, siphons formed by fusion of inner mantle folds (“ Type A” of Yonge, 1982). Incurrent siphonal opening (Figures 30, 32, IS) located ventrally, much larger (at least twice as wide) than that of excurrent siphonal opening (Figures 30, 32, 33, ES); siphonal cowl (Figure 32, SC) inverted, resting inside infraseptal chamber, covering incurrent siphonal opening internally, probably eversible for prey capture, relatively short. Base of incurrent siphon surrounded by 15 tentacles (Figures 30–32, TN); tentacles simple, tapered. Large unpaired tentacle (Figures 30, 32, UT) present along fused mantle margin dorsal to excurrent siphonal opening; following six (3 + 3) tentacles deployed along membranous hem-like projection of middle mantle fold on each side of intersiphonal junction. Remaining eight tentacles arranged around incurrent siphonal opening. Incurrent siphonal opening located almost ventrally, at least twice as wide as excurrent siphonal opening. Excurrent siphonal opening located posteriorly; angle formed by junction of margins of two valves in posterior direction subtending excurrent siphonal opening (Figures 30, 33). MANTLE CAVITY: Septum (Figure 32, SE) located dorso-ventrally within mantle cavity; septum roughly parallel to anterior shell surface. Septum thin, strong, dividing the mantle cavity into two chambers, the supraseptal (posterior) (Figure 32, SSC) and infraseptal (anterior) (Figure 32, ISC) chambers. Septum attaching to dorsal region of shell posterior to anterior adductor muscles but attaching to ventral region of shell anterior to posterior adductor muscle. Septum perforated by byssal opening (Figure 58 [left], BO) and by groups of ostia arranged to define three pairs of line segments deployed around byssal opening, roughly delineating a hexagon. Ostia distributed as follows: three anterior (Figure 58 [left], ASO), four median (Figure 58 [left], MSO), and four posterior (Figure 58 [left], PSO). MAJOR SHELL MUSCLES: Strong modification of shell shape associated with shape and positioning of adductor muscles: adductor muscles almost parallel to valve surfaces to which they are attached. Anterior adductor muscles (Figures 31, 32, AA) short, flattened; posterior adductor muscles (Figures 30, 32, PA) longer, also flattened. Posterior byssal retractor muscles (Figure 30, 32, PBR) Y-shaped, very well developed, attaching to locations close to posterior margin of valves. Anterior byssal retractor muscles much thinner, attaching dorsally to internal surface of entrance to umbonal cavity. Septal attachment muscles difficult to observe given poor preservation of specimens. BYSSUS AND FOOT: Byssus (Figures 31, 32, BY) well-developed, prominent, circular in cross section, in preserved animals attached to grains of calcareous sediment, consisting of bundle of very fine, fused filaments, cylindrical in cross-section. Byssus originating from a thickened section of vestigial foot (Figure 31, F), which is narrow and filiform. Position and size of vestigial foot indicates that it might never exit infraseptal chamber. MOUTH AND LABIAL PALPS: Mouth ridged internally along entire circumference; posterior labial palps reduced to two vestigial projections flush with surrounding surface. Anterior labial palps very well developed, broad, folded over mouth, potentially expandable in posterodorsal direction. ALIMENTARY SYSTEM: Esophagus with strong folds, very short, opening anterodorsally into stomach. Stomach (Figure 30, ST) of Type II, compact, slightly elongate dorsoventrally, forming posteroventral projection, internally ridged, with ridges stronger in ventral surface. Crystalline style situated just ventral to esophagus opening, projecting slightly into stomach, surrounded by chitinous shield. Openings of digestive diverticula not observed because of poor fixation. Digestive diverticula located in dorsal “horns” (Figures 30, DD). Midgut short, connecting to stomach anteroventral position, ventral to esophagus, curving to more posterodorsal position, anus opening in supra-septal chamber near opening of excurrent siphon between posterior byssal retractor muscles. STOMACH CONTENTS: Examination of stomach contents of four paratypes revealed, in one specimen, partially digested remains of unidentifiable ostracod species. KIDNEYS: Kidneys situated posterodorsally between the remainder of visceral mass and posterior byssal retractor muscle. Kidneys comprising two elongate structures, one on each side of the midline of posterior region (Figure 30, K). REPRODUCTIVE SYSTEM: Testes (Figure 31, TE) elongated situated in anteroventral position in relation to ovaries, ovary overlying the testes. Ovaries (Figures 30, OV) consisting of pair of elongated sacs symmetrically deployed on each side of midline. Ovaries and testis ventral to digestive diverticula. Type material. Holotype, BMSM 15029, (length×height×width [in mm] = 7.41×20.37×16.55) Paratype 1, USNM 1112670 (6.61×16.76×14.87). Paratype 2, UF 416419 (7.85×17.34×14.90), Paratype 3, collection of Steve Kern unnumbered (6.79×17.24×14.52), Paratype 4, collection of Frank Frumar (6 × 16 × 14; not measured with same accuracy as other types), unnumbered. All from type locality, Steve Kern coll. May 2006, dredged, lobster boat. Type locality. Southwest of Key West, Monroe County, Florida, USA, 229 m depth. Abbreviations: AAS = scar of anterior adductor muscle; ABS = scar of anterior byssal retractor muscle; ASC = scar of anterior septal muscle; CIL = calcified part of inner ligament layer; CT = cardinal-like tooth; HS = hinge socket; IL = inner ligament layer; LAT = lateral tooth; LG = lateral groove; LI = ligament; OL = outer ligament layer; PAL = pallial line; PAS = scar of posterior adductor muscle; PBS = scar of posterior byssal retractor muscle; PE = periostracum; OL = outer ligament layer; U = umbo. Etymology. The new species is named simultaneously after Frank Frumar and Steve Kern, for kindly making the material available for study. Remarks on habitat and type locality. The depth given above for the type locality is as related by the collector. The two other congeners (below) were collected much deeper, between 805 and 961 m depth. Remarks. See comparative remarks below, under Dilemma spectralis new species and Dilemma inexpectatum new combination.Published as part of Leal, Jos Ẽ H., 2008, A remarkable new genus of carnivorous, sessile bivalves (Mollusca: Anomalodesmata: Poromyidae) with descriptions of two new species, pp. 1-18 in Zootaxa 1764 on pages 5-8, DOI: 10.5281/zenodo.18199
Azimuthal anisotropy of Lg attenuation in eastern Tibetan Plateau
No full textThe Q of seismic phase Lg is measured to approach the crustal Q(beta), which can be used to infer crustal rheology. A reverse two-station/event method is used to measure the interstation Q(Lg), which theoretically eliminates effects from the source and site response. Strong azimuthal anisotropy of 1/Q(Lg) in northern Tibet is observed, which approximately correlates with the seismic velocity anisotropy observed using both surface waves and teleseismic S waves. Both the intrinsic and scattering attenuation contribute the isotropic Q, whereas the anisotropic Q may be associated with the fractures and faults in the crust. Strong 1/Q(Lg) is observed in the northwestern Songpan-Ganzi fold belt, where the high-Q directions correspond with the orientations of major strike-slip faults. Intrinsic and scattering Q values are estimated for different tectonic terranes in eastern Tibetan Plateau. The intrinsic Q values are approximately 500 in the northern Tibetan Plateau, which suggests a hot (similar to 700 degrees C) crust, consistent with low seismic velocity measurements. Our result suggests that the crust of northwestern Songpan-Ganzi fold belt may be hotter than that of the Qiangtang terrane, which may be related to the strain heating along the major strike slip fault zones that dominate the northernmost Tibet.Geochemistry & GeophysicsSCI(E)5ARTICLEnull11
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