The term microcirculation refers to the group of blood vessels that have a diameter less than $100\mu \mathrm{m}$, which includes arterioles, meta-arterioles, capillaries, and venules.^1,2 It plays an essential role in delivering oxygen to cells and regulating blood pressure by modifying vascular resistance.^{1 – 4} Under normal physiological conditions, the microcirculatory status aligns with macrohemodynamic variables, such as blood pressure, heart rate, and cardiac output. However, in certain pathological states, such as sepsis or during shock resuscitation, this correlation can be disrupted, leading to a condition known as loss of hemodynamic coherence. In this state, microcirculation may be compromised even when macrohemodynamic variables remain within normal limits. This phenomenon is also referred to as microcirculatory shock.^{3,5 – 7}

Dissimilar aluminum joints have widespread applications across various industries, including the electronics and automotive sectors, owing to their unique combination of advantages, including reduced density and enhanced mechanical properties. These characteristics make them an innovative solution for multi-material processing challenges presented in the engineering industry. This article focuses on Friction Stir-Welded butt joints made using a weld–flip–weld approach between aluminum AA6061-T6 and pure copper C11000, exploring the effects of varying rotational speeds (1000, 1200, and 1400 RPM), offsets (0 and 1 mm) in the joint soundness, mechanical strength, and electrical conductivity. The welds were evaluated using non-destructive testing with phased-array ultrasound and tensile testing. Additionally, the electrical conductivity was measured to assess their response to electrical currents. The findings reveal a significant correlation between joint efficiency and electrical conductivity, with the highest values corresponding to a weld executed with a rotational speed of 1400 rpm, traverse speed of 40 mm/min, and 1 mm offset towards the aluminum, achieving the highest joint efficiency, reaching a joint efficiency of approximately 75% and 82.42% of the IACS for electrical conductivity.

The viscoelastic properties of the lung have important implications during respiratory mechanics in terms of lung movement or work of breathing, for example. However, this property has not been well characterized due to several reasons, such as the complex nature of the lung, difficulty accessing its tissues, and the lack of physical simulators that represent viscoelastic effects. This research proposes an electropneumatic system and a method to simulate the viscoelastic effect from temporary forces generated by the opposition of magnetic poles. The study was tested in a mechanical ventilation scenario with inspiratory pause, using a Hamilton-S1 mechanical ventilator (Hamilton Medical) and a simulator of the human respiratory system (SAMI-SII). The implemented system was able to simulate the stress relaxation response of a Standard Linear Solid model in the Maxwell form and showed the capacity to control elastic and viscous parameters independently. To the best of our knowledge, this is the first system incorporated into a physical lung simulator that represents the viscoelastic effect in a mechanical ventilation scenario.

Friction Stir Welding (FSW) has the advantage of generating sound welds on materials that generally present low weldability by traditional fusion welding processes, such as 2xxx and 7xxx aluminum alloys. Force measurement in FSW provides significant information about the process, the machine requirements, the effect of selected parameters, and weld soundness. In this paper, an axial force measuring device was designed, built, and tested to be used in a CNC adapted system. All tests were performed using AA 7075-T6 and a butt joint configuration. The forces obtained by the device match, in profile, key values, and trends, the ones found in literature which allows to conclude that this is a functional and sufficient device for the application.