The current paper aims to present a cooling concept for future centralized platforms of ECUs (Electronic Control Units) from the automotive industry that involves grouping multiple electronic devices into a single system and cooling them with forced convection dielectric coolant. The enhancement consists of replacing the inside air of the module with a dielectric coolant that has a higher thermal conductivity than air and employing an additional prototype system that aids in forced liquid cooling. To meet automotive requirements, the experiments were exposed to an ambient temperature of 85 °C. Temperature measurements on these solutions’ hot spots were compared to those on a thermal paste-only reference electronic module. This study used DFSS (Design for Six Sigma) techniques to determine the ideal pump flow rate, fan air flow rate, and liquid volume in the housing, leading to an optimization in heat dissipation. Finding a trustworthy transfer function that could forecast the impact of the crucial design parameters that had been found was the main goal. The electronics cooled by forced convection coolant improved heat dissipation by up to 60% when compared to the reference module. This demonstrates that the DoE (Design of Experiments) method, which is based on a limited number of measurements, can estimate the behavior of the ECU without the need for a more involved theoretical framework.

Background: This study explored the potential of MCM-48 mesoporous silica matrices as a drug delivery system for metformin hydrochloride, aimed at improving the therapeutic management of type 2 diabetes mellitus. The objectives included the synthesis and characterization of MCM-48, assessment of its drug loading capacity, analysis of drug release profiles under simulated physiological conditions, and the development of a multifractal dynamics-based theoretical framework to model and interpret the release kinetics. Methods: MCM-48 was synthesized using a sol–gel method and characterized by SEM-EDX, TEM, and nitrogen adsorption techniques. Drug loading was performed via adsorption at pH 12 using metformin hydrochloride solutions of 1 mg/mL (P-1) and 3 mg/mL (P-2). In vitro dissolution studies were conducted to evaluate the release profiles in simulated gastric and intestinal fluids. A multifractal dynamics model was developed to interpret the release kinetics. Results: SEM-EDX confirmed the uniform distribution of silicon and oxygen, while TEM images revealed a highly ordered cubic mesoporous structure. Nitrogen adsorption analyses showed a high specific surface area of 1325.96 m²/g for unloaded MCM-48, which decreased with drug loading, confirming efficient incorporation of metformin hydrochloride. The loading capacities were 59.788 mg/g (P-1) and 160.978 mg/g (P-2), with efficiencies of 99.65% and 89.43%, respectively. In vitro dissolution studies showed a biphasic release profile: an initial rapid release in gastric conditions followed by sustained release in intestinal fluids, achieving cumulative releases of 92.63% (P-1) and 82.64% (P-2) after 14 hours. The multifractal dynamics-based theoretical release curves closely matched the experimental data. Conclusions: MCM-48 mesoporous silica effectively enhanced metformin delivery, offering a controlled release profile well-suited for type 2 diabetes management. The multifractal theoretical framework provided valuable insights into drug release dynamics, contributing to the advancement of innovative drug delivery systems.

This paper presents a study on the movement precision and accuracy of an extruder system related to the print bed on a 3D printer evaluated using the features of 2D circular trajectories generated by simultaneous displacement on x and y-axes. A computer-assisted experimental setup allows the sampling of displacement evolutions, measured with two non-contact optical sensors. Some processing procedures of the displacement signals are proposed in order to evaluate and to describe the circular trajectories errors (e.g., open and closed curves fitting, the detection of recurrent periodical patterns in x and y-motions, low pass numerical filtering, etc.). The description of these errors is suitable to certify that the 3D printer works correctly (keeping the characteristics declared by the manufacturer) for maintenance purpose sand, especially, for computer-aided correction of accuracy (e.g., by error compensation).

This paper presents some advances in condition monitoring for rotary machines (particularly for a lathe headstock gearbox) running idle with a constant speed, based on the behaviour of a driving three-phase AC asynchronous induction motor used as a sensor of the mechanical power via the absorbed electrical power. The majority of the variable phenomena involved in this condition monitoring are periodical (machines having rotary parts) and should be mechanically supplied through a variable electrical power absorbed by a motor with periodical components (having frequencies equal to the rotational frequency of the machine parts). The paper proposes some signal processing and analysis methods for the variable part of the absorbed electrical power (or its constituents: active and instantaneous power, instantaneous current, power factor, etc.) in order to achieve a description of these periodical constituents, each one often described as a sum of sinusoidal components with a fundamental and some harmonics. In testing these methods, the paper confirms the hypothesis that the evolution of the electrical power (instantaneous and active) has a predominantly deterministic character. Two main signal analysis methods were used, with good, comparable results: the fast Fourier transform of short and long signal sequences (for the frequency domain) and the curve fitting estimation (in the time domain). The determination of the amplitude, frequency and phase at origin of time for each of these components helps to describe the condition (normal or abnormal) of the machine parts. Several achievements confirm the viability of this study: a characterization of a flat driving belt condition and a beating power phenomenon generated by two rotary shafts inside the gearbox. For comparison purposes, the same signal analysis methods were applied to describe the evolution of the vibration signal and the instantaneous angular speed signal at the gearbox output spindle. Many similarities in behaviour among certain mechanical parts (including their electrical power, vibration and instantaneous angular speed) were highlighted.

In this paper we studied the influence of micromachining parameters on processed surface quality. Usually in discussions about micro-cutting or micromachining, the grinding or diamond turning processes are considered. Cutting tools used in the mentioned processes do not have regular constructive geometry and, in this case, it is difficult to use constructive geometric parameters such as clearance angle α or rake angle γ to optimize the quality of the machined surface. In order to determine the influence of the cutting tool’s constructive geometry on the hardness of the machined material, we used a fractional factorial design of a centered and rotatable type 2⁶⁻¹. A mathematical model based on five independent cutting parameters was created that allowed optimization of surface quality based on obtained roughness. The results can be applied in micromilling or microturning.

This paper experimentally reveals some of the resources offered by the instantaneous active electric power in describing the state of three-phase AC induction asynchronous electric motors (with a squirrel-cage rotor) operating under no-load conditions. A mechanical power is required to rotate the rotor with no load, and this mechanical power is satisfactorily reflected in the constant and variable part of instantaneous active electric power. The variable part of this electrical power should necessarily have a periodic component with the same period as the period of rotation of the rotor. This paper proposes a procedure for extracting this periodic component description (as a pattern by means of a selective averaging of instantaneous active electrical power) and analysis. The time origin of this pattern is defined by the time of a selected first passage through the origin of an angular marker placed on the rotor, detectable by a proximity sensor (e.g., a laser sensor). The usefulness of the pattern in describing the state of the motor rotor has been demonstrated by several simple experiments, which show that a slight change in the no-load running conditions of the motor (e.g., by placing a dynamically unbalanced mass on the rotor) has clear effects in changing the shape of the pattern.