An accelerated flow around a sphere

AbstractA solution for the initial laminar boundary-layer flow around a sphere which suddenly starts to move with the velocity U = U0 + U1t + U2t2 has been developed in powers of the time from the start of the motion. The time series is valid past the time when separation occurs and a number of characteristic flow properties can be calculated to third order

A Study Of Oseen Flow Using Integral Conditions

The primary objective of this work is to analyze the steady two-dimensional flow of a viscous incompressible fluid past a conformally-mappable cylinder in an unbounded field. The main concern is the correct satisfaction of the boundary conditions at large distances from the cylinder. It is shown that the steady-state asymmetrical flow problem needs careful examination, particularly with regard to the satisfaction of these conditions. A general method is developed to solve this class of problem, under the assumption that flow is governed by the Oseen linearized equations of motion. The method is based on satisfaction of the proper conditioning for the vorticity of integral type. This is considered as a very important part of the solution procedure since the integral conditions ensure both the correct decay of the vorticity at large distances from the cylinder and satisfaction of the physically essential results for the existence of the flow. For Oseen flow the method enables one to obtain the vorticity separately from the stream function.;As an example of the application of the method, the uniform flow past an elliptic cylinder at an arbitrary angle of incidence at low Reynolds number R sc E is considered. An analytical expression for the vorticity on the surface of the elliptic cylinder is obtained correct to the order of (R sc E) (lnR sc E) {dollar}\sp{lcub}-1{rcub}{dollar}, the lowest order term being O((lnR sc E) {dollar}\sp{lcub}-1{rcub}).{dollar} The leading terms for the asymptotic expansions for the life, drag coefficients and the circulation round a large contour surrounding the elliptic cylinder are determined in terms of R sc E. In this case the Reynolds number R sc E is based on the length of the major axis of the ellipse. The method is also applied to the cases of symmetrical and asymmetrical flows past circular cylinders. A paradox is obtained for asymmetrical flow generated by a rotating circular cylinder. The first Oseen paradox may be stated as No steady two-dimensional asymmetrical Oseen flow of a viscous incompressible fluid past a rotating circular cylinder is possible . It is found to be impossible to obtain a solution in this case in which the circulation is non-zero

Representations Of the ‘Self’ and the ‘Other’ In Travel Narratives: Daniel Defoe’s Robinson Crusoe and A.W. Kinglake’s Eothen

As travel and travel accounts are as old as history of mankind. With the beginnings of first examples of literary writings, it is hard to separate travelling and writing within each other. Looking at the 18th century travel literature and its tendencies, this paper explores the argument that the narrative of travel allows the writer to imagine and disseminate images of the self. Defoe and Kinglake, through the discourse of the travel narrative, portray idealised images of the “self” in the construction of the central character and that this is based on social ideals of the time. This paper also shows briefly the idea in both works that is important to the representation of “self” is the representation of the home culture. The main question for this essay could be, to what extent that the narrative of travel allows the writer to imagine and disseminate images of the Self

"Rain Follows the Plow" and Dryfarming Doctrine: The Climate Information Problem and Homestead Failure in the Upper Great Plains, 1890-1925.

In the late 19th and early 20th centuries, the North American agricultural frontier moved into semi-arid regions of the Great Plains where farming was vulnerable to drought. Farmers who migrated to the region had to adapt their crops, techniques, and farm sizes to better fit the environment. But there was very incomplete information for making these adjustments, and ultimately they were insufficient: too many small, dry-land wheat farms were founded, only to be abandoned in the midst of drought. Two episodes of homestead settlement and collapse in western Kansas in 1893-94 and in eastern Montana in 1917-21 are examined. We go beyond the existing literature by explicitly detailing the weather information problem facing settlers and showing precisely why widespread homestead failure occurred. We present a Bayesian learning model to indicate how new climate information was incrementally incorporated to revise views of agricultural prospects. Primary data are used to show the lagged response of homesteaders to new drought information and to illustrate the differential impact of drought on small farms. Dryfarming doctrine arose as a solution to the problems faced by farmers in the region. Despite its optimistic claims, it was an imperfect response to drought. Indeed, some dryfarming practices increased the likelihood of homestead failure. "No one need be in doubt about the sharp change in climate that occurs somewhere between the 96th and 100th meridians. It can be felt on the lips and skin, observed in the characteristic plant and animal life, seen in the clarity and/or dustiness of the atmosphere, determined by measurements of rainfall and evaporation, tested by attempts at unaided agriculture. Practically every western traveler in the early years remarked the facts of aridity, though not all used the word 'desert'.." Stegner (1954, 399) "Dame Nature of the West holds out most alluring charms, and those who woo and win her smile reap a reward beyond compare. The one thing most needed is correct and accurate information."Buffin (1909, 16) "That dry-farming is a system of agricultural practice which requires the application of high skill and intelligence is admitted; that it is precarious is denied. The year of drought is ordinarily the year in which the man failed to do properly his share of the work." Widtsoe (1911, 412).

"Rain Follows the Plow" and Dryfarming Doctrine: The Climate Information Problem and Homestead Failure in the Upper Great Plains, 1890-1925

In the late 19th and early 20th centuries, the North American agricultural frontier moved for the first time into semi-arid regions where farming was vulnerable to drought. Farmers who migrated to the region had to adapt their crops, techniques, and farm sizes to better fit the environment. But there was very incomplete information for making these adjustments, and ultimately they were insufficient: too many small, dry land wheat farms were founded, only to be abandoned in the midst of drought. In this paper, we examine why homestead failure occurred in the Great Plains, by analyzing two episodes in western Kansas in 1893-94 and in eastern Montana in 1917-21. We focus on the weather information problem facing migrants to the region. We examine the learning process by which migrants mis-interpreted new rainfall information and failed to adequately perceive drought. Homesteaders had neither an analytical framework nor sufficient data for predicting fluctuations in rainfall. Knowledge of the climate was primitive and the underlying mechanisms triggering droughts were not understood. Long-term precipitation records did not exist. Homesteaders gambled on the continuation of previous wet periods due to a possible climate change because of cultivation, and on the optimistic opinions of dryfarming experts.' Dryfarming doctrine argued that moisture could be saved in the soil, allowing small wheat farms to endure any dry period. Accordingly, homesteaders discounted new information that indicated drought. The subsequent waves of homestead busts that swept the region during severe droughts were part of the adjustment toward agricultural techniques, crops, and farm sizes more appropriate for a semi-arid region.

Der Bologna Prozess

Eines der wesentlichen Diskussionsthemen an Universitäten in der letzten Dekade war und ist der Bologna-Prozess. Die vorliegende Studie behandelt diesen Prozess und versucht, diese aktuelle Thematik im Zusammenhang mit den Begriffen Globalisierung, Internationalisierung und Europäisierung zu bearbeiten. Ziel dieser Arbeit ist es, die Hintergründe und Schritte dieses Prozesses aus politischer Perspektive zu behandeln und unterschiedliche Blicke darauf zu bieten. Dafür war eine vorhergehende Analyse der Globalisierungs-, Internationalisierungs-, und Europäisierungsprozesse im Hochschulbereich notwendig. Wiederum wurde der theoretische Zugang der Arbeit behandelt. In diesem Sinne wurde Funktionalismus im Zusammenhang mit dem Bologna-Prozess bearbeitet. Nach der Bearbeitung des Hintergrunds des Bologna- Prozesses werden dessen Entwicklungsverlauf und seine Neuheiten aufgezeigt. Aus Sicht der aktuellen Situation des Prozesses werden auch Ausblicke auf die Zukunft dargestellt.Since the last decade, one of the major topics of discussion at universities has been the Bologna Process. This thesis deals with the process in connection with the terms globalization, internationalization and Europeanization. The aim of this work is to provide background information and give details about the phases of the process from a political point of view. For that, preceding analysis of globalization, internationalization and Europeanization processes in higher education was required. Besides, the theoretical framework of the Bologna process was also discussed. In this sense, Bologna Process has been linked to functionalism. After pointing out the background of the Bologna process, its evolution and effects were identified. The current situation of the process has been applied to its future

The influence of post-fixation on visualising vimentin in the retina using immunofluorescence method

Background: Post-fixation of sections is especially required for cryostat sections of fresh frozen tissues. Vimentin is an intermediate filament in both fibrillary and non-fibrillary form, expressed in Müller’s cells and astrocytes of the retina. Our aim was to determine the best post-fixation method for visualising vimentin in archival mouse eyes. Materials and methods: We used an archival mouse eye, slightly pre-fixed with paraformaldehyde and stored at –80°C for 4 years. We tried three fixatives (pa­raformaldehyde [PFA], alcohol/acetic acid [AAA] and methanol) for post-fixation of eye sections. Results: We showed that post-fixation alters the labelling properties of vimentin expressed in the retina. In the sections with no post-fixation, vimentin positivity was observed in and around the nuclei in non-fibrillary form. In PFA post-fixed sections, the vimentin in the retina was not observed as fibrils. Positivity was observed in the nuclei and in perinuclear regions of the cells. In AAA post-fixed sections, positive labelling was observed around the nuclei as fibrils. In methanol post-fixed sections, labelling was observed around the nuclei as fibrils. Conclusions: We conclude that post-fixation with AAA is more convenient for immunofluorescent labelling of vimentin in the retina for slightly PFA pre-fixed and long-term stored retina. (Folia Morphol 2018; 77, 2: 246–252

Formation of the sural nerve in foetal cadavers

The purpose of this study was to provide a morphologic description and assessmenton the formation level of the sural nerve (SN) and its components. Alsowe aimed to reveal histological features of the SN components. An anatomicalstudy of the formation of the SN was carried out on 100 limbs from 50 embalmedfoetuses. The results showed that the SN was formed by the union ofthe medial sural cutaneous nerve (MSCN) and the peroneal communicatingbranch (PCB) in 71% of the cases (Type A); the MSCN and PCB are branches ofthe tibial and common peroneal nerve (CPN) or lateral sural cutaneous nerves(LSCN), respectively. Formation level of the SN was at the distal third of the legin 43% of the cases, at the middle third of the leg in 46% of the cases, and atthe upper third of the leg in 11% of the cases. The PCB originated in the CPN in68% and the PCB originated in the LSCN in 3% of the cases. The SN wasformed only by the MSCN in 20% of the cases (Type B). Type C was divided intofour subgroups: in the first group the PCB and fibres of the posterior femoralcutaneous nerve joined the MSCN in 4% of cases; in the second group theMSCN, PCB, and sciatic nerve did not unite and coursed separately in 1% ofcases; in the third group the SN arose directly from the sciatic nerve alone andthe MSCN made a little contribution in 2% of cases; and in the fourth groupthe PCB, fibres of the sciatic nerve, and the MSCN formed the SN in 1% of thecases. The SN was formed only by the PCB in 1% of the cases (Type D). Distancesof the formation level of the SN to the intercondylar line and the lateralmalleolus were measured and also noted. A detailed knowledge of the anatomyof the SN and its contributing nerves are important in many interventionalprocedures