Refrigerators are one of the most extensively used household appliances, accounting for approximately 4% of total household electricity consumption. Enhancing their energy performance can significantly reduce residential energy demand. As a result, this study focuses on reducing the energy consumption of a French-door, bottommount refrigerator using isobutane (R600a) as the working fluid. The performance improvement of the refrigerators has been obtained mainly through improving the vapor compression refrigeration cycle, with a particular emphasis on condenser design. This study explores the impact of three-pass serpentine microchannel condenser on energy performance, along with the effects of two distinct fan combinations. Charge optimization experiments were conducted to identify the optimal refrigerant mass for the refrigerator unit with microchannel condenser. Additionally, a comprehensive numerical model was developed to analyze the behavior of vapor compression cycle under various refrigerant charges. The experimental findings revealed that the refrigerator unit with the three-pass microchannel condenser reduces the energy consumption of isobutane-based domestic refrigerators up to 16% while reducing the refrigerant charge by 11% in comparison to the refrigerator unit with conventional wire-and-tube condenser.
Elastomeric composites are increasingly recognized as promising materials for thermal insulation applications in building technologies, owing to their unique blend of mechanical flexibility, thermal resistance, and durability. Utilizing sheet molding compounding (SMC), a versatile and efficient manufacturing method, enables the production of high-performance elastomeric fiber composites. In this study, we focus on formulating hydroxy-terminated polydimethylsiloxane (PDMS) composites reinforced with glass micro-balloons (GMBs). These formulations are designed to not only provide the necessary rheological properties for SMC processing but also to impart desirable thermomechanical characteristics to the cured PDMS composites. Our investigation explores the impact of filler content on the cure kinetics, rheological behavior, thermal insulation, and hardness properties of the PDMS composites. PDMS formulations with GMB contents below 40 wt.
Probabilistic uncertainties in the model parameters result in distributional uncertainties in the model predictions. While such uncertainty descriptions have been incorporated into model predictive control (MPC) formulations using polynomial chaos theory (PCT), more care is required to ensure integral action than in traditional MPC. This article thoroughly examines offset-free formulations of PCT-based MPC for multiple-input, multiple-output linear time-invariant systems. We compile, prove, and validate features of multiple stochastic MPC formulations. Under mild assumptions, these features include (i) guarantees for the existence of a full column-rank integrator to eliminate offset in multiple performance indices; (ii) guarantees of nominal closed-loop stability for the unconstrained systems, and (iii) computationally efficient, spectrally accurate resolution of parametric uncertainty. Application of our stochastic MPC formulations to setpoint tracking and disturbance rejection in numerical case studies demonstrate the asymptotic removal of offset in all higher-order contributions to output variation due to parametric uncertainty.
This article provides an overview of the smooth particle hydrodynamics (SPH) approach and its mathematical modeling. SPH is a numerical technique based on a mesh-free Lagrangian scheme for evaluating the continuum mechanics problems. This method is suitable in the case of continuum objects undergoing large deformation, as conventional finite element methods are unreliable due to mesh failure and convergence issues. It is a widely used approach in the field of astrophysics, fluid mechanics, structural mechanics, soil mechanics, automobiles, and so on. A numerical example is also considered in this research paper to demonstrate the applicability of the method. The simulation process was achieved using LS-Dyna explicit solver software, and plots related to cutting and thrust forces, von Mises stress, plastic strain, temperature distribution, and so on, were obtained. Also, the effect of Time-Scaling Factor (TSSFAC) on SPH simulations was observed in this research.
We present WSSAMNet, a weakly supervised method for medical image registration. Ours is a two step method, with the first step being the computation of segmentation masks of the fixed and moving volumes. These masks are then used to attend to the input volume, which are then provided as inputs to a registration network in the second step. The registration network computes the deformation field to perform the alignment between the fixed and the moving volumes. We study the effectiveness of our technique on the BraTSReg challenge data against ANTs and VoxelMorph, where we demonstrate that our method performs competitively.
