Laser-powder bed fusion additive manufacturing (LPBF-AM) of metals is rapidly becoming one of the most important materials processing pathways for next-generation metallic parts and components in a number of important applications. However, the large parametric space that characterizes laser-based LPBF-AM makes it challenging to understand what are the variables controlling the microstructural and mechanical property outcomes. Sensitivity studies based on direct LPBF-AM processing are costly and lengthy to conduct, and are subjected to the specifications and variability of each printer. Here we develop a fast-throughput numerical approach that simulates the LPBF-AM process using a cellular automaton model of dynamic solidification and grain growth. This is accompanied by a polycrystal plasticity model that captures grain boundary strengthening due to complex grain geometry and furnishes the stress-strain curves of the resulting microstructures. Our approach connects the processing stage with the mechanical testing stage, thus capturing the effect of processing variables such as the laser power, laser spot size, scan speed, and hatch width on the yield strength and tangent moduli of the processed materials. When applied to pure Cu and stainless 316L steel, we find that laser power and scan speed have the strongest influence on grain size in each material, respectively.

Psychological research on empathy typically focuses on understanding its effects on empathizers and empathic targets. Little is known, however, about the effects of empathy beyond its dyadic context. Taking an extradyadic perspective, we examined how third-party observers evaluate empathizers. Seven experiments documented that observers' evaluations of empathizers depend on the target of empathy. Empathizers (vs. nonempathizers) of a stressful experience were respected/liked more when the empathic target was positive (e.g., children's hospital worker), but not when the target was negative (e.g., White supremacist; Experiments 1 and 2). Empathizers were respected/liked more when responding to a positive target who disclosed a positive experience (i.e., a personal accomplishment), but less when responding to a negative target who disclosed a positive experience (Experiment 3). These effects were partly, but not solely, attributable to the positivity of empathic responses (Experiment 4). Expressing empathy (vs. condemnation) toward a negative target resulted in less respect/liking when the disclosed experience was linked to the source of target valence (i.e., stress from White supremacist job; Experiments 5 through 7), but more respect/liking when the experience was unrelated to the source of target valence (i.e., stress from cancer; Experiment 7). Overall, empathizers were viewed as warmer, but to a lesser extent when responding to a negative target. These findings highlight the importance of considering the extradyadic impact of empathy and suggest that although people are often encouraged to empathize with disliked others, they are not always favored for doing so. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

An innovative cross-layer routing approach, MCORCA (Multi-Channel On-demand Routing with Coordinate Awareness), is presented that utilizes multiple channels to im- prove the performance of wireless ad-hoc networks. The proposed cross-layer scheme adapts the strategy of channel assignment and the mechanism of dealing with conflicts. Channels are divided into a control channel and data channels; the control channel is used for scheduling, and data channels are used for data transmissions. MCORCA is an extension of an on- demand routing protocol for single channel wireless networks, called ORCA (On-demand Routing with Coordinates Awareness). Simulation results indicate that MCORCA yields a significant capacity improvement as well as lower end-to-end delays by using multiple channels.

The majority of the routing protocols designed to date for mobile ad hoc networks (MANET) rely on flooding of route requests for the establishment of routes on demand. A novel approach called CBORCA (Cut-Based On-demand Routing with Coordinate Awareness) is introduced. CBORCA improves the efficiency with which route requests are disseminated by parti- tioning the designated route forwarders in distinct quadrants and by selecting at most one “pivot” within each quadrant. Each new pivot is required to pass a distance test before joining the pivot set. Message complexity at each hop is shown to be O(C) ≍ O(1). Experimental results using simulations demonstrate that the performance of CBORCA achieves better results than ORCA (On-demand Routing with Coordinate Awareness) in packet- delivery ratio, signaling overhead, and end-to-end delay.

The rapid growth of urban areas and concerns over climate change make it vital to improve the energy sustainability of cities. Understanding the complex interactions within different sectors (sectoral) and localities (spatial) of cities plays a crucial role in improving efficiency and sustainability, which is extremely challenging due to the complex urban morphology. State-of-the-art energy concepts do not facilitate a detailed consideration of both sectoral and spatial coupling that energy infrastructure maintains at the urban scale. This has become a significant challenge when designing interconnected urban energy infrastructure. The Urban Cell concept is introduced to address this bottleneck. A novel computational model using a modular approach is introduced to create an interconnected urban infrastructure, including the energy, building, and transportation sectors. Optimal sizing of the distributed energy system (including renewables, energy storage, and dispatchable sources) and optimal urban morphology is determined within a modular unit. A game-theoretic approach is used to model the interactions between urban cells (modular units). The study revealed that the urban cell concept can reduce the net present value of the interconnected energy infrastructure by 37% while increasing the installed renewable energy capacity by 25%. This demonstrates the benefit potential of urban cells and the importance of considering interactions between different sectors and different parts within a city. The Urban Cell concept can be used to present the complex interactions maintained within a city.