This study explores the efficacy of dimples in influencing the aerodynamic performance of a straight rectangular wing. Computational Fluid Dynamics based numerical simulations were performed to model turbulent flow and quantify the forces exerted on the wing. The k-ω Shear-Stress Transport turbulence model was chosen to solve the underlying equations. To ascertain reliability, the results of numerical simulations were compared with both experimental and simulation results of the previous studies. The impact of various dimple configurations, placed at 15%, 50% and 85% of the chord length, on the aerodynamic performance of the wing was investigated. The evaluation involved analyzing the drag coefficient (CD), lift coefficient (CL), lift-to-drag (L/D) ratio, streamlines and the flow field around wing in both chordwise and spanwise directions. The findings indicated that a wing with a dimpled surface could yield a reduced drag coefficient of up to 6.6% compared to the unmodified wing. This reduction is attributed to the dimples ability to sustain attached airflow and delay flow separation. The results demonstrated negligible deviation in the lift coefficient with the incorporation of dimples. The incorporation of dimples on the wing surface has been demonstrated to enhance the aerodynamic performance of lifting surfaces.

This paper presents the results of an experimental study to evaluate the possibility of using SLM additive technology to produce structures with specific surface morphological features. Qualitative and quantitative tests were conducted on samples fabricated by 3D printing from titanium (Ti6Al4V)-powder-based material and analysed in direct relation to the possibility of their use in medicine for the construction of femoral stem and models with a specific degree of porosity predicted by process-control in the self-decision-making 3D printing machine. This paper presents the results of the study, limitations of the method, recommendations that should be used in the design of finished products, and design proposals to support the fabrication process of 3D printers. Furthermore, the study contains an evaluation of how the printing direction affects the formation of certain structures on the printed surface. The research can be used in the development of 3D printing standardization, particularly in the consideration of process control and surface control.

This paper described unique hysteresis phenomena that appear in the hydrodynamic lubrication properties of dimpled thrust bearings. A seal-type thrust bearing specimen was textured with dimples. The load-carrying capacity and frictional torque were measured with a constant film thickness and compared to those of a dimple-free specimen. For examining the size of cavitation bubbles that occurred in various conditions, the lubricating area was observed during experiments. The used dimpled specimen produced the load-carrying capacity, and it exhibited an interesting hysteresis phenomenon, the difference in the values in the increasing and decreasing processes of rotational speed. The visualization test results revealed that the size of cavitation bubbles occurring within the dimples strongly affected this phenomenon. In addition, the dimpled specimen was able to reduce the frictional torque compared to the dimple-free specimen. However, the frictional torque did not show the hysteresis loop similar to that shown in the load-carrying capacity.

In this paper, the influence of occurrence of surface texture features on the values of surface topography parameters calculated after the application of various data processing techniques was presented. Different types of surface topographies were considered, as follows: cylinder liners, some with additionally burnished dimples, turned, ground, milled, laser-textured, composite, ceramic, or isotropic in general. The effects of feature size on the areal form removal, noise suppressions, or end-effect reducing in surface texture measurements were studied. The variations of the ISO 25178 standard surface topography parameters were taken into consideration in detail. It was assumed that some of the feature sizes, distributions, and densities have a substantial impact on the values of surface topography parameters calculated after applications of regular (commonly used) algorithms and procedures, defined as basic operations, provided for raw surface texture data obtained directly from the measurement process. In the end, some of the practical applications for receiving the relevant values of surface topography parameters were proposed.

AlSi10Mg alloy branches were fabricated by selective laser melting (SLM), and the branches were employed to evaluate their effect on the mechanical properties. When the porous branches were compressed along its building direction, the tree column structures-type AlSi10Mg alloy branches collapsed twice, which had typical elastic, shear, collapse, and densification stages. The compressive stress concentration at the interface between the support and the porous body caused the fracture of the tree column structures-type AlSi10Mg alloy branches. The fracture surface indicated that the prepared tree-type branches were distributed with different shapes of dimples, and the Si content inside the dimples was higher than that of the edge. The morphology of the Al-Si eutectic structure formed by SLM and the stress concentration at the Al/Al-Si-eutectic interface affected the fracture morphology and Si content distribution.

This review presents a summary of the results in the domain of microscopic liquid film hydrodynamics for several decades of experimental and theoretical research. It mainly focuses on the validation, application and further development of the Stefan-Reynolds theory on the liquid drainage, based on the accumulated knowledge of surface forces, surface tension caused by the surfactant adsorption, and diffusion of surfactants. Liquid films are of primary significance for colloidal disperse systems, and diverse industrial processes. The transient stability of the froth phase and the froth drainage is a function of the drainage and rupture of liquid films between air bubbles. In flotation, the bubble-particle attachment is controlled by the thinning and rupture of the intervening liquid film between an air bubble and a mineral particle. Both the experimental and theoretical results are mostly related to the foam liquid films between two bubbles, but can be principally generalized for emulsion films, formed in another liquid, as well as wetting films between a bubble and a solid surface.

Of individuals with Amyoplasia, 16.8% (94/560) involve only the upper limbs (Upper Limb Amyoplasia-ULA) and 15.2% (85/560) involve only the lower limbs (Lower Limb Amyoplasia-LLA). The accompanying paper deals with other forms of Amyoplasia [Hall et al., 2013] and discusses etiology. An excess of one of monozygotic (MZ) twins is seen in both groups (ULA 4/94 (4.3%), LLA 5/85 (5.9%)), gastrointestinal (GI) abnormalities thought to be of vascular origin (bowel atresia and gastroschisis) (ULA 16/94 (17%), LLA 4/85 (4.7%)), small or partial absence of digits (ULA 6/94 (6.2%), LLA 8/85 (9.4%)), and umbilical cord wrapping around the limbs at birth (ULA 3/94 (3.2%), LLA 7/85 (8.2%)) (severe enough to leave a permanent groove). Pregnancy complications occurred in 42/60 (70%) of ULA and 36/54 (67%) of LLA. Prenatal diagnosis, after ultrasound usage became routine, occurred in only 7/25 (28%) of ULA and 5/12 (12%) of LLA. This series may represent an over estimate of the complications and associations occurring in ULA and LLA. Differential diagnoses separating LLA from the genetic forms of \"lower limb only\" arthrogryposis and ULA from \"upper limb only\" genetic forms of arthrogryposis and Erb\'s palsy is provided.