Parallel flow in Hele-Shaw cells with ferrofluids

Parallel flow in a Hele-Shaw cell occurs when two immiscible liquids flow with relative velocity parallel to the interface between them. The interface is unstable due to a Kelvin-Helmholtz type of instability in which fluid flow couples with inertial effects to cause an initial small perturbation to grow. Large amplitude disturbances form stable solitons. We consider the effects of applied magnetic fields when one of the two fluids is a ferrofluid. The dispersion relation governing mode growth is modified so that the magnetic field can destabilize the interface even in the absence of inertial effects. However, the magnetic field does not affect the speed of wave propagation for a given wavenumber. We note that the magnetic field creates an effective interaction between the solitons.Comment: 12 pages, Revtex, 2 figures, revised version (minor changes

On the association between greater family identification and lower paranoid ideation among non-clinical individuals: evidence from Cypriot and Spanish students

A large literature has provided evidence of the 'social cure': a positive relationship between group identification (a sense of group belonging) and mental wellbeing, commonly measured in terms of levels of depression, anxiety, or stress. However, non-clinical populations may experience other symptoms of mental distress, including paranoia. We hypothesised that since group identification promotes satisfying and supportive relationships (something paranoid individuals appear to lack), there should be a negative relationship between family identification and paranoid ideation. We confirmed this in a cross-sectional study with Cypriot students (N = 108) and in a two-wave longitudinal study with Spanish students (N = 206). The second study also revealed that family identification predicts paranoia over time, but not vice versa. These studies are the first to confirm that family identification is a negative predictor of paranoid ideation, and highlight the need to further explore the effects of group identification on psychotic-like symptoms

Improving the Spatial Accuracy of UAV Platforms Using Direct Georeferencing Methods: An Application for Steep Slopes

The spatial accuracy of unmanned aerial vehicles (UAVs) and the images they capture play a crucial role in the mapping process. Researchers are exploring solutions that use image-based techniques such as structure from motion (SfM) to produce topographic maps using UAVs while accessing locations with extremely high accuracy and minimal surface measurements. Advancements in technology have enabled real-time kinematic (RTK) to increase positional accuracy to 1–3 times the ground sampling distance (GSD). This paper focuses on post-processing kinematic (PPK) of positional accuracy to achieve a GSD or better. To achieve this, precise satellite orbits, clock information, and UAV global navigation satellite system observation files are utilized to calculate the camera positions with the highest positional accuracy. RTK/PPK analysis is conducted to improve the positional accuracies obtained from different flight patterns and altitudes. Data are collected at altitudes of 80 and 120 meters, resulting in GSD values of 1.87 cm/px and 3.12 cm/px, respectively. The evaluation of ground checkpoints using the proposed PPK methodology with one ground control point demonstrated root mean square error values of 2.3 cm (horizontal, nadiral) and 2.4 cm (vertical, nadiral) at an altitude of 80 m, and 1.4 cm (horizontal, oblique) and 3.2 cm (vertical, terrain-following) at an altitude of 120 m. These results suggest that the proposed methodology can achieve high positional accuracy for UAV image georeferencing. The main contribution of this paper is to evaluate the PPK approach to achieve high positional accuracy with unmanned aerial vehicles and assess the effect of different flight patterns and altitudes on the accuracy of the resulting topographic maps

Long waves in parallel flow in Hele-Shaw cells

During the past several years the flow of immiscible flow in Hele-Shaw cells and porous media has been investigated extensively. Of particular interest to most studies has been frontal displacement, specifically viscous fingering instabilities and finger growth. The practical ramifications regarding oil recovery, as well as many other industrial processes in porous media, have served as the primary driving force for most of these investigations. By contrast, little attention has been paid to the motion of lateral fluid interface, which are parallel to the main flow direction. Parallel flow is an often encountered, although much overlooked regime. The evolution of fluid interfaces in parallel flow in Hele-Shaw cells is studied both theoretically and experimentally in the large capillary number limit. It is shown that such interfaces support wave motion, the amplitude of which for long waves is governed by the KdV equation. Experiments are conducted in a long Hele-Shaw cell that validate the theory in the symmetric case. 35 refs., 16 figs

Effects of thermal annealing on the morphology of the AlxGa(1x)N films

Cataloged from PDF version of article.Effects of thermal annealing on the morphology of the AlxGa(1-x)N films with two different high Al-contents (x=0.43 and 0.52) have been investigated by atomic force microscopy (AFM). The annealing treatments were performed in a nitrogen (N-2) gas ambient as short-time (4 min) and long-time (30 min). Firstly, the films were annealed as short-time in the range of 800-950 degrees C in steps of 50-100 degrees C. The surface root-mean-square (rms) roughness of the films reduced with increasing temperature at short-time annealing (up to 900 degrees C), while their surface morphologies were not changed. At the same time, the degradation appeared on the surface of the film with lower Al-content after 950 degrees C. Secondly, the Al0.43Ga0.57N film was annealed as long-time in the range of 1000-1200 degrees C in steps of 50 degrees C. The surface morphology and rms roughness of the film with increasing temperature up to 1150 degrees C did not significantly change. Above those temperatures, the surface morphology changed from step-flow to grain-like and the rms roughness significantly increased. (C) 2009 Elsevier Ltd. All rights reserved

LOCALIZATION AND MORPHOMETRY OF MANDIBULAR FORAMEN

Foramen mandibulae, ramus mandibulae'nın orta kısmının arkasında bulunur, içinden nervus alveolaris inferior ve damarlar geçer. Amaç: Bu çalışmanın amacı, foramen mandibulae'nın morfometrik ölçümlerinin ve lokalizasyonunun belirlenmesidir. Gereç ve Yöntem: Bu çalışma 102 kuru mandibula'da yapıldı (204 taraf). Foramen mandibulae'larda altı ayrı morfometrik ölçüm yapıldı. Foramen mandibulae ile caput mandibulae, ramus mandibulae'nın arka kenarı, ramus mandibulae'nın ön kenarı, corpus mandibulae'nın alt kenarı, incisura mandibulae ve angulus mandibulae arası uzaklıklar ölçüldü. Bulgular: Foramen mandibulae ile caput mandibulae, ramus mandibulae'nın arka kenarı, ramus mandibulae'nın ön kenarı, corpus mandibulae'nın alt kenarı, incisura mandibulae'nın en derin noktası ve angulus mandibulae'nın en çıkıntılı noktası arası ortalama uzaklıklar sırasıyla, sağda 41,73 ± 3,97 mm; 14,32 ± 2,09 mm; 12,86 ± 2,46 mm; 29,51 ± 3,93 mm; 23,65 ± 3,38 mm; 22,80 ± 4,32 mm ve solda 41,36 ± 4,37 mm; 14,59 ± 2,13 mm; 12,77 ± 1,90 mm; 26,39 ± 4,05 mm; 24,18 ± 3,02 mm; 22,18 ± 3,90 mm olarak ölçüldü. Sağ ve sol taraf karşılaştırmasında foramen mandibulae ile incisura mandibulae'nın en derin noktası ve foramen mandibulae ile angulus mandibulae'nın en çıkıntılı noktası arası uzaklıkların ortalama değerleri anlamlı bir fark gösterdi. Sonuç: Foramen mandibulae'nın lokalizasyonu, mandibular anestezide, ağız içi girişimlerde, dentofasyal deformitelerin restorasyonunda ve maksillofasyal cerrahide önemlidir. Mandibular sinirin hasarından kaçınmak için bu bölge anatomisinin iyi bilinmesi gerekmektedir. Bu çalışmada, foramen mandibulae'nın morfometrik anatomisini ve lokalizasyonunu tanımlamaya çalıştık. Bu bilgilerden diş hekimliğinde, ağız içi, maksillofasyal cerrahide yararlanılabilir. Mandibular foramen is located just posterior to the middle of the ramus of mandible which transmits the inferior alveolar nerve and vessels. Objective of this study is to determine the localization and morphometric measurements of mandibular foramen. Material and methods: This study was conducted on 102 dry mandibles (204 sides). Six morphometric measurements were taken from mandibular foramen. The tances between mandibular foramen and head of mandible, posterior margin of ramus of mandible, anterior margin of ramus of mandible, inferior margin of mandibular body, the deepest point of mandibular notch and the most prominent point of mandibular angle were measured. Results: The average distances between mandibular foramen and head of mandible, mandibular foramen and posterior margin of ramus of mandible, mandibular foramen and anterior margin of ramus of mandible, mandibular foramen and inferior margin of mandibular body, mandibular foramen and the deepest point of mandibular notch and mandibular foramen and the most prominent point of mandibular angle were 41.73 ± 3.97 mm; 14.32 ± 2.09 mm; 12.86 ± 2.46 mm; 29.51 ± 3.93 mm; 23.65 ± 3.38 mm; 22.80 ± 4.32 mm on the right side and 41.36 ± 4.37 mm; 14.59 ± 2.13 mm; 12.77 ± 1.90 mm; 26.39 ± 4.05 mm; 24.18 ± 3.02 mm; 22.18 ± 3.90 mm on the left side, respectively. The correlation between distance of mandibular foramen - the deepest point of mandibular notch and mandibular foramen- the most prominent point of mandibular angle on the left and right side were showed significant difference. Conclusion: The localization of mandibular foramen is important in mandibular anesthesia, oral procedures, restoration of dentofacial deformities and maxillofacial surgery. It is necessary to know this anatomic area for avoiding to damage mandibular nerve. In this study, we tried to determine the localization and morphometric anatomy of mandibular foramen. These information may be helpful for oral procedures, maxillofacial surgery and dentistry

Incorporation of Y2O3 Particles into 410L Stainless Steel by a Powder Metallurgy Route

Addition of yttria to steels has been proposed for the fabrication of oxide-dispersion-strengthened materials for nuclear power applications. We have investigated materials prepared from 12 Cr martensitic stainless steel, AISI 410L, produced by powder metallurgy. Materials were produced with and without yttria addition, and two different sizes of yttria were used, 0.9 µm and 50 nm. Tensile and mini-creep tests were performed to determine mechanical properties. Optical microscopy, SEM, TEM, and EDX analysis were used to investigate the microstructures and deformation mechanisms and to obtain information about non-metallic inclusion particles. SiO2, MnS, and Y2Si2O7 inclusion particles were observed. An SiO2 and Y2O3 interaction was seen to have occurred during the ball milling, which impaired the final mechanical properties. Small-angle neutron scattering experiments showed that the matrix chemistry prevented effective dissolution of the yttria. © The Author(s) 201

Exploiting a wheat EST database to assess genetic diversity

Expressed sequence tag (EST) markers have been used to assess variety and genetic diversity in wheat (Triticum aestivum). In this study, 1549 ESTs from wheat infested with yellow rust were used to examine the genetic diversity of six susceptible and resistant wheat cultivars. The aim of using these cultivars was to improve the competitiveness of public wheat breeding programs through the intensive use of modern, particularly marker-assisted, selection technologies. The F2 individuals derived from cultivar crosses were screened for resistance to yellow rust at the seedling stage in greenhouses and adult stage in the field to identify DNA markers genetically linked to resistance. Five hundred and sixty ESTs were assembled into 136 contigs and 989 singletons. BlastX search results showed that 39 (29%) contigs and 96 (10%) singletons were homologous to wheat genes. The database-matched contigs and singletons were assigned to eight functional groups related to protein synthesis, photosynthesis, metabolism and energy, stress proteins, transporter proteins, protein breakdown and recycling, cell growth and division and reactive oxygen scavengers. PCR analyses with primers based on the contigs and singletons showed that the most polymorphic functional categories were photosynthesis (contigs) and metabolism and energy (singletons). EST analysis revealed considerable genetic variability among the Turkish wheat cultivars resistant and susceptible to yellow rust disease and allowed calculation of the mean genetic distance between cultivars, with the greatest similarity (0.725) being between Harmankaya99 and Sönmez2001, and the lowest (0.622) between Aytin98 and Izgi01

Left ventricular morphology and function in adolescents: Relations to fitness and fatness.

BACKGROUND: Obesity in childhood predisposes individuals to cardiovascular disease and increased risk of premature all-cause mortality. The aim of this study was to determine differences in LV morphology and function in obese and normal-weight adolescents. Furthermore, relationships between LV outcomes, cardiorespiratory fitness (CRF) and adiposity were explored. METHODS: LV morphology was assessed using magnetic resonance imaging (MRI) in 20 adolescents (11 normal-weight [BMI equivalent to 18kg/m(2)-25kg/m(2)] and 9 obese [BMI equivalent to ≥30kg/m(2)]); 13.3±1.1years, 45% female, Tanner puberty stage 3 [2-4]) using magnetic resonance imaging (MRI). Global longitudinal strain (GLS), strain rate (SR) and traditional echocardiographic indices were used to assess LV function. CRF (peak oxygen consumption), percent body fat (dual-energy x-ray absorptiometry), abdominal adipose tissue (MRI), and blood biochemistry markers were also evaluated. RESULTS: Adolescents with obesity showed significantly poorer LV function compared to normal-weight adolescents (P0.05). Moderate to strong associations between myocardial contractility and relaxation, adiposity, arterial blood pressure and cardiorespiratory fitness were noted (r=0.49-0.71, P<0.05). CONCLUSION: Obesity in adolescence is associated with altered LV systolic and diastolic function. The notable relationship between LV function, CRF and adiposity highlights the potential utility of multidisciplinary lifestyle interventions to treat diminished LV function in this population. CLINICAL TRIAL REGISTRATION: NCT01991106