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Directed energy deposition (DED) additive manufacturing (AM) enables the production of components at a high deposition rate. For certain alloys, interpass temperature requirements are imposed to control heat accumulation and microstructure transformation, as well as to minimize distortion under varying thermal conditions. A typical strategy to comply with interpass temperature constraints is to increase the interpass dwell time, which can lead to an increase in the total deposition time. This study aims to develop an optimized tool path that ensures interpass temperature compliance and reduces overall deposition time relative to the conventional sequential deposition path during the DED process. To evaluate this, a compact analytic thermal model is used to predict the thermal history during laser-based directed energy deposition (DED-LB/M) hot wire (lateral feeding) of ER100S-G, a welding wire equivalent to high yield steel. A greedy algorithm, integrated with the thermal model, identifies a tool path order that ensures compliance with the interpass requirement of the material while minimizing interpass dwell time and, thus, the total deposition time. The proposed path planning algorithm is validated experimentally with in situ temperature measurements comparing parts fabricated with the baseline (sequential) deposition path to the modified path (resulting from the greedy algorithm). The experimental results of this study demonstrate that the proposed path planning algorithm can reduce the deposition time by 9.2% for parts of dimensions 66 mm × 73 mm × 16.5 mm, comprising 15 layers and a total of 300 beads. Predictions based on the proposed path planning algorithm indicate that additional reductions in deposition time can be achieved for larger parts. Specifically, increasing the (experimentally validated) part dimension perpendicular to the deposition direction by five-times is expected to result in a 40% reduction in deposition time. 

Laser Hot Wire (LHW) Directed Energy Deposition (DED) Additive Manufacturing (AM) processes are capable of manufacturing parts with a high deposition rate. There is a growing research interest in replacing large cast Nickel Aluminum Bronze (NAB) components using LHW DED processes for maritime applications. Understanding thermomechanical behavior during LHW DED of NAB is a critical step towards the production of high-quality NAB parts with desired performance and properties. In this paper, finite element simulations are first used to predict the thermomechanical time histories during LHW DED of NAB test coupons with an increasing geometric complexity, including single-layer and multilayer depositions. Simulation results are experimentally validated through in situ measurements of temperatures at multiple locations in the substrate as well as displacement at the free end of the substrate during and immediately following the deposition process. The results in this paper demonstrate that the finite element predictions have good agreement with the experimental measurements of both temperature and distortion history. The maximum prediction error for temperature is 5% for single-layer samples and 6% for multilayer samples, while the distortion prediction error is about 12% for single-layer samples and less than 4% for multilayer samples. In addition, this study shows the effectiveness of including a stress relaxation temperature at 500 °C during FE modeling to allow for better prediction of the low cross-layer accumulation of distortion in multilayer deposition of NAB. 

ABSTRACT Linear enamel hypoplasias (LEHs) are development defects appearing as lines or grooves on enamel surfaces. Forming when physiological stressors disrupt developing teeth, LEHs provide retrospective insight into stress experienced in early development. Here, LEHs in Cayo Santiago rhesus macaques (Macaca mulatta) were observed with respect to decade of birth, whether an individual was transferred from the free‐ranging colony to the captive facility during probable crown formation periods, and matriline of birth. It was hypothesized that later decades would exhibit higher prevalence than earlier decades as climatic conditions in Puerto Rico worsened over time. Transfer was expected to affect LEH formation because the process of transfer, and subsequent restriction to captivity, is thought to be stressful. Matriline membership was hypothesized to relate to LEH formation because there is some evidence of a genetic influence on susceptibility to form LEH and because offspring of matrilines of different dominance ranks are known to experience different levels of aggression. Lower third premolars with minimal enamel surface wear were scored for LEH using a digital microscope, while a follow‐up analysis of the two matrilines with the most extreme differences in LEH frequency was conducted using enamel surface profiles. Results were: (1) individuals born during the 1990s had significantly greater LEH prevalence than those born in the 1960s, (2) transferred individuals exhibited weak evidence of greater LEH prevalence than nontransferred comparison groups, and (3) matrilines did not differ in LEH expression in the initial or follow‐up analysis. Although sample sizes were small for some comparisons, these results suggest that not all decades saw an equal prevalence of LEH, that there might be a small effect of transfer from free‐ranging to captive conditions on LEH prevalence that is difficult to detect, and that the matriline into which an individual is born is not related to LEH expression. 

Abstract The Cayo Santiago rhesus macaque colony represents one of the most important nonhuman primate resources since their introduction to the Caribbean area in 1938. The 85 years of continuing existence along with the comprehensive database of the rhesus colony and the derived skeletal collections have provided and will continue to provide a powerful tool to test hypotheses about adaptive and evolutionary mechanisms in both biology and medicine. 

Biological nanopores are increasingly used in molecular sensing due to their single-molecule sensitivity. The detection of per- and polyfluoroalkyl substances (PFAS) like perfluorooctanoic acid and perfluorooctane sulfonic acid is critical due to their environmental prevalence and toxicity. Here, we investigate selective interactions between PFAS and four cyclodextrin (CD) variants (α-, β-, γ-, and 2-hydroxypropyl-γ-CD) within an α-hemolysin nanopore. We demonstrate that PFAS molecules can be electrochemically sensed by interacting with a γ-CD in a nanopore. Using HP-γ-CDs with increased steric resistance, we can identify homologs of the perfluoroalkyl carboxylic acid and the perfluoroalkyl sulfonic acid families and detect common PFAS in drinking water at 0.4 to 2 parts per million levels, which are further lowered to 400 parts per trillion by sample preconcentration. Molecular dynamics simulations reveal the underlying chemical mechanism of PFAS-CD interactions. These insights pave the way toward nanopore-based in situ detection with promises in environmental protection against PFAS pollution. 

Abstract Cupin dioxygenases such as salicylate 1,2‐dioxygense (SDO) perform aromatic C−C bond scission via a 3‐His motif tethered iron cofactor. Here, transient kinetics measurements are used to monitor the catalytic cycle of SDO by using a nitro‐substituted substrate analog, 3‐nitrogentisate. Compared to the natural substrate, the nitro group reduces the enzymatick_catby 500‐fold, thereby facilitating the detection and kinetic characterization of reaction intermediates. Sums and products of reciprocal relaxation times derived from kinetic measurements were found to be linearly dependent on O₂concentration, suggesting reversible formation of two distinct intermediates. Dioxygen binding to the metal cofactor takes place with a forward rate of 5.9×10³ M⁻¹ s⁻¹: two orders of magnitude slower than other comparable ring‐cleaving dioxygenses. Optical chromophore of the first intermediate is distinct from thein situgenerated SDO Fe(III)−O₂⋅⁻complex but closer to the enzyme‐substrate precursor. 

The rich records of Rhesus macaques at Cayo Santiago (CS) with detailed information of individual and family relationships enables extended genetic analyses of the reproductive history of the colony. As a part of a collaborative effort to build a Knowledge Model of the history of health of the CS Rhesus colony, this study further delves into the intricate social group interactions and reproduction dynamics to provide an integrated perspective for a deeper understanding of familial connections and genetic aggregations. Leveraging matrilineal lineage developed from previous work and patrilineal tracing made available since mid-1970’s, as well as inter-group transfer data, this study attempted to provide retrospective views of group evolution history, with an emphasis on dyad interactions regarding their natal and transferred groups. Employing tools and techniques popular in social community analysis, including graph database and Gephi, this study conducted a comparative analysis focused on animals born between 2005 and 2014. Preliminary results indicated that communities identified by using Gephi matched well with census records, while deviations from historical sketches of group evolution summaries existed as well. Upcoming results from using Neo4j, a graph database system, will be compared with these findings, which can be integrated more smoothly with CSViewer for Analysts, the graphical user interfaces for the CS Knowledge Model to be introduced in a workshop at AABA 2024 annual meeting. Findings of this research can help add one more perspective to pathological studies seeking correlations with environmental factors such as food provision and natural disasters like hurricanes. 

Abstract--The Cayo Santiago rhesus, established and maintained for 85 years, has evolved into a valuable resource for researchers across various disciplines. This research paper outlines an ongoing NSF project aimed at developing a comprehensive database and user-friendly software application, CSViewer, to uncover hidden knowledge. Using a big data approach, the paper focuses on key events in the colony's population dynamics, emphasizing gender-specific analyses. It also explores data exploration and preparation processes, along with the application of the genealogy model in inbreeding analysis and genetic tracing. Future efforts, including the expansion of CSViewer's functions, are also addressed.