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In the present work, three-dimensional computational fluid dynamics analysis is employed to study the droplet dynamics of Newtonian and non-Newtonian droplets impinging on a hot surface under various impact conditions. The Navier–Stokes equations for unsteady, incompressible, and viscous fluid flow are solved using a control volume method. The volume-of-fluid (VOF) technique is also used to track the free-surface of the liquid. The effect of viscosity, density and surface tension on droplet dynamics is evaluated considering their dependence of temperature. The results indicate that the temperature dependence of the both Newtonian and non-Newtonian physicochemical liquid properties must be considered to obtain better agreement of the numerical results with experimental data. After ensuring the accuracy of the numerical methodology, the internal behavior of the droplets is examined, which is shown that the receding velocity of the non-Newtonian droplet is slower than the Newtonian one.

The flow structures of jet impingement dominate heat and mass transfer process, even the whole thermal performance. In this study, we have inspected the flow structures and mechanism of nanofluid jet impingement onto a dimpled target surface with different design parameters. Investigations are performed for the relative depth of dimple ($\delta /D$), the jet-to-plate spacing ($H/d$), nanoparticle volume concentration ($\varphi$), and Reynolds number (Re) ranging to explore the mechanism of flow structure variations. Results indicate that these parameters have a significant effect on the flow structure of nanofluid jet impingement near the dimpled target surface. The flow begins to separate after passing the edge of the dimple along with the curvature of a dimple. $\delta /D$ will affect the form and location of flow separation and reattachment, and $\varphi$ will affect the intensity of separation flow. The length of the flow separation bubble varies in different $H/d$ cases. When $H/d$ increases, the impinging energy and the velocity near the dimple edge decreases. The different Re has little effect on the length of the flow separation bubble and the tendency of the pressure coefficient (Cp). These results can provide further mechanism inspiration for the design of the flow structure of nanofluid jet impingement.

We present a case of radiocapitellar impingement caused by osteochondral fragment after type II capitellar fracture. Painful extension limitation of the elbow was treated successfully by diagnostic arthroscopy and mini-open removal of loose body. A displaced type II capitellar fracture in children is extremely rare, but must be carefully diagnosed and treated.

Rotator cuff tendinosis is a disease whose etiology and pathophysiology are still under debate. Three mechanisms have been proposed as giving rise to rotator cuff disease: the intrinsic mechanism, the extrinsic mechanism and overuse. Evidence for and against each one as being the primary cause of disease abounds. The current consensus is that the etiology is probably multifactorial and each factor plays different roles in different patients. The histologic features of rotator cuff disease are fibroblast hyperplasia, collagen disorganization and neovascularization. These findings together are termed angiofibroblastic hyperplasia, believed to be a reflection of unsuccessful attempts at repair of tendon with a tendency towards degeneration. The concept supports the current view that rotator cuff disease is a tendinosis, a degenerative process, rather than a tendinitis, an inflammatory one. This poor healing response is seen in the collagen content of diseased tendon. Production of collagen fails to shift from the initial type III collagen to the mature type I collagen, causing the tendon to become weak. Most current treatment modalities fail to address the biologic processes going on within the tendon and future directions need to address these problems.

Rapid progress in science and information technology, growing manufacturing activities and increase in globalization have boosted the demand for advanced electronics devices. Moreover, increase in microprocessor power dissipation coupled with the reduction in feature sizes due to manufacturing process improvements have resulted in continuously increasing heat fluxes. Thus, ever increasing heat fluxes have required the development of novel, reliable and affordable thermal management technologies. Although some of those proposed solutions for high flux cooling problems based on liquid cooling methods such as spray and evaporative cooling; air cooling is still commonly preferred due to its availability, reliability, easiness and low cost. Therefore, over the last decade microfluidics devices such as synthetic jets have been investigated as an alternative to conventional air moving devices, and have been shown as highly effective for cooling of electronics in compact thermal real estates.

Synthetic jets are meso scale fluidics devices, which operate on the “zeronet-mass-flux” principle. However, they create a positive net momentum flux to the external environment, and are able to produce effective cooling similar to a fan without posing ducting, reliability, and large dimension issues. These devices, which alternate suction and ejection of fluid through an orifice bounding a small cavity, by the time periodic motion of a diaphragm built into one of the walls of the cavity. A unique feature of these jets is that they are formed entirely from the working fluid in which they are deployed. Moreover, unlike conventional jets, synthetic jets produce fluid flow with no mass addition to the system and without the need for complex plumbing. Since, the rate of heat removal from the thermal source is expected to depend on the location, orientation, strength, and shape of the jet, in the current paper, an overview of the state of the art for synthetic jet technology, research, design approaches and also possible applications is presented. Heat transfer enhancements in natural and forced convection, recent progresses in modeling and heat transfer predictions are presented. Finally, recent practical applications of synthetic jets are discussed.