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Geometric Sensitivity of Measured Rotations in Axial Moment-Rotation Response for 2D Models of Longitudinal Joints in Segmental Tunnel Liners
No full textSegmental tunnel lining systems cannot be considered as continuous rings due to the existence of longitudinal joints. Each joint is characterized by an axial load-dependent moment-rotation behavior. Numerous studies have used numerical models to explain this segment interaction at a joint contact, but have not defined the importance of how model rotations are measured. In this study, multiple 2D numerical simulations of flat non-bolted longitudinal joints are performed in positive bending with ABAQUS. When using nodal displacements to quantify the joint rotation behavior of longitudinal joints the selection of this location is critical to plotting the correct response. Due to the geometric sensitivity of longitudinal joint profiles, the selection of nodal displacement locations is investigated. The modeling techniques employed to simulate this behavior as well as existing theoretical solutions to moment-rotation behavior are carefully described and discussed. Modeling techniques were verified using a segment profile with a general joint geometry and loading scheme, and then additional models were developed to compare with the experiments conducted by Hordijk and Gijsbers (1996) and Ouyang (2024). It was concluded that selecting a distance on either side of the simulated joint equal to the depth of the jointcontact yields the closest results to theoretical and experimental behaviors. More specifically, selecting the edge of the joint deformation zone defined by Janssen (1983) produces a curve with the most accurate behavior at large rotations (after joint opening). Selecting a nodal distance equal to the full thickness of the segment yielded the highest resemblance of initial rotational stiffness to Janssen\u27s theoretical solution</p
STEM Interest and Achievement in High School Freshmen with ADHD: Multisystemic Predictors
No full textThe transition from middle to high school can be especially challenging for students with attention-deficit/hyperactivity disorder (ADHD). Also, students with disabilities experience greater barriers when considering careers in science, technology, engineering, and math (STEM) fields. Academic interest and social support may play a critical role in self-regulatory processes and school success in this period. The current study investigated the roles of school-level support, parent support, teacher emotional support, and teacher academic support on math/science interest development and overall high school math/science high school grade point average (GPA) among about 1,730 ninth grade students with ADHD entering high school (70% male). The average age of students was 14.55 (SD = .69). A national dataset from the High School Longitudinal Study of 2009 (HSLS:09) was analyzed using structural equation modeling (SEM). It was hypothesized that all types of social support would positively predict math/science interest development and achievement. It was also hypothesized that ninth and 11th grade math/science interest would mediate the relationship between social supports and achievement. Students with ADHD demonstrated unique motivational and achievement patterns. School-level support did not predict any outcome variables, and parent support negatively predicted science interest. Perceived teacher emotional support positively predicted ninth grade interest across domains. Teacher support for deep cognitive engagement positively predicted math GPA, but teacher support for surface cognitive engagement negatively predicted math/science interest. Surprisingly, academic interest emerged as a negative predictor of GPA in both domains. Mediation effects were observed, but potential suppression effects complicated the interpretation of results. The findings highlight the importance of providing developmentally appropriate and individualized supports for increasing interest and achievement in high school students with ADHD. </p
Implementing Recycling Methods for Linear Systems in Python with an Application to Multiple Objective Optimization
No full textSequences of linear systems arise in the predictor-corrector method when
computing the Pareto front for multi-objective optimization. Rather than
discarding information generated when solving one system, it may be
advantageous to recycle information for subsequent systems. To accomplish this,
we seek to reduce the overall cost of computation when solving linear systems
using common recycling methods. In this work, we assessed the performance of
recycling minimum residual (RMINRES) method along with a map between
coefficient matrices. For these methods to be fully integrated into the
software used in Enouen et al. (2022), there must be working version of each in
both Python and PyTorch. Herein, we discuss the challenges we encountered and
solutions undertaken (and some ongoing) when computing efficient Python
implementations of these recycling strategies. The goal of this project was to
implement RMINRES in Python and PyTorch and add it to the established Pareto
front code to reduce computational cost. Additionally, we wanted to implement
the sparse approximate maps code in Python and PyTorch, so that it can be
parallelized in future work
Representing the World in Language and Thought
No full textInternal representations guide our navigation of the world, while language allows us to share some of what is encoded internally with others. I have been interested in the content of thought, the nature of word meanings and what they reveal about thought, and how thoughts are expressed in words. My work has combined evidence from laboratory experimentation with observation of word use in natural settings, including from people who speak different languages. Some of the ideas guiding the work are these: understanding entities in the world non‐linguistically engages different representations and processes than talking about them; patterns of word use in a language reflect cultural and linguistic history, not only conceptual representations of current speakers; linguistic and non‐linguistic knowledge is therefore at least partially independent, and so language and thought will not always closely parallel one another; the beliefs people express about their concepts and word meanings may not accurately reflect the implicit knowledge they draw on in interacting with and talking about the world; and only by carefully observing actual word use can we understand how word meanings come about and how linguistic knowledge is used to select words for communication. , I have been interested in thought, word meanings, and how thoughts are expressed in words. My work has used laboratory experiments and observations in natural settings and includes evidence from children and people who speak different languages. This paper provides an overview of my program of research
Individualized Language Plans
No full textIn the United States, individualized language plans (ILPs) have gained traction across K–12 schools. Much like the Individualized Education Programs (IEPs) used in special education, ILPs outline individualized goals, accommodations, and services for multilingual learners for their language development; however, unlike IEPs, ILPs are developed at the local level with no federal oversight or guidance. While scholars have recently called for the implementation of ILPs as a mechanism for promoting systemic change, there is a scarcity of scholarship that critically discusses or examines ILPs. In response to this gap, in this Teaching Issue article, we draw upon a combination of prior research, policy guidance, and our own review of ILP templates mandated or recommended in various states across the United States, to identify the characteristics, affordances, and constraints of ILPs. After discussing the promises and pitfalls of large‐scale implementation of these tools, we close this paper with two recommendations for teachers and policymakers who may consider adopting ILPs: to emphasize instructional support and a multiplicity of data and voices
Surface Analysis Insight Note
No full textIt is common practice to describe the coordination of metal atoms in a binding configuration with their nearest neighbors in terms of oxidation state, a measure by which the number of electrons redistributed between atoms forming chemical bonds. In XPS terms, change to an oxidation state is commonly inferred by correlating photoemission signal with binding energy. The assumption, when classifying photoemission signals into distinct spectral shapes, is that a distribution of intensities shifted to lower binding energy is evidence of a reduction in oxidation state. In this Insight note, we raise the prospect that changes in photoemission peak shape may occur without obvious changes, determined by XPS in stoichiometry for a material. It is well known that TiO 2 measured by XPS yields reproducible Ti 2p photoemission peaks. However, on exposing TiO 2 to ion beams, Ti 2p photoemission evolves to complex distributions in intensity, which are particularly difficult to analyze by traditional fitting of bell‐shaped curves to these data. For these reasons, in this Insight note, a thin film of TiO 2 deposited on a silicon substrate is chosen for analysis by XPS and linear algebraic techniques. Alterations in spectral shapes created from modified TiO 2 , which might be interpreted as the change in oxidation state, are assessed in terms of relative proportions of titanium to oxygen. It is found through detailed analysis of spectra that quantification by XPS, using procedures routinely used in practice, is not in accord with the typical interpretations of photoemission shapes. The data processing methods used and results presented in this work are of particular relevance to elucidating fundamental phenomena governing the surface evolution of materials‐enabled energy processes where cyclic/non‐steady usage changes the nature of bonding, especially in the presence of contaminants
Future transition from forests to shrublands and grasslands in the western United States is expected to reduce carbon storage
No full textAbstractClimate change is expected to impact vegetation in the western United States, leading to shifts in dominant Plant Functional Types and carbon storage. Here, we used a biogeographic model integrated with a biogeochemical model to predict changes in dominant Plant Functional Type by 2070‚àí2100. Results show that under the Representative Concentration Pathway 4.5 scenario, 40% of the originally forested areas will transition to shrubland (7%) or grassland (32%), while under the Representative Concentration Pathway 8.5 scenario, 58% of forested areas shift to shrubland (18%) or grassland (40%). These shifts in Plant Functional Types result in a net overall loss in carbon storage equal to ‚àí60 gigagram of carbon and ‚àí82 gigagram of carbon under Representative Concentration Pathway 4.5 and 8.5, respectively. Our findings highlight the need for urgent action to mitigate the effects of climate change on vegetation and carbon storage in the region.</jats:p
Computational Fluid Dynamic Analysis of a High-Pressure Spatial Chemical Vapor Deposition (HPS-CVD) Reactor for Flow Stability
No full textHigh indium-content group-III nitrides are of interest to further expand upon our ability to produce highly efficient optical emitters at longer visible/IR wavelengths or to broaden bandgap engineering opportunities in the group-III nitride material system. Current synthesis approaches are limited in their capabilities, in part due to the low decomposition temperature of indium nitride. A new high-pressure spatial chemical vapor deposition (HPS-CVD) has been proposed which can operate at pressures up to 100 atmospheres, thereby significantly raising the growth temperature of indium nitride more than 100 kelvins and permitting the investigation of the impact of pressure on precursor stability and reactivity. This study systematically analyzes an HPS-CVD reactor design using computational fluid dynamic modeling in order to understand favorable operating conditions for growth of group III nitrides. Specifically, the relationship between inlet gas type (nitrogen, hydrogen, or ammonia), inlet gas velocity, gas flow rate, and rotational speed of the wafer carrier is evaluated for conditions under which a smooth and dominant vortex-free flow are obtained over the wafer. Heater power was varied to maintain a wafer temperature of 1250–1300 K. Favorable operating conditions were identified that were simultaneously met for all three gas types, providing a stable operating window for a wide range of gas chemistries for growth; at one atmosphere, a disk rotational speed of 50 rpm and a flow rate of 12 slm for all gas types is desired.</jats:p
Partisan animosity through the lens of blame: Partisan animosity can be reduced by a historicist thinking intervention
No full textPartisan animosity has been on the rise in America. Partisan animosity involves blame, wherein political partisans blame outparty members for their beliefs and actions. Here, we examine whether a historicist thinking intervention—drawn from research on blame mitigation—can reduce partisan animosity. The intervention consisted of three components: (1) a narrative about the idiosyncratic development of one political opponent paired with (2) a message about how unique life experiences shape everyone’s political beliefs and (3) a suggestion that outparty members can be changed by future formative experiences. Experiments 1 and 2 showed that the intervention reduced cold feelings—measured via Feeling Thermometer—towards the outparty for both Democrats and Republicans. Experiments 3 and 4 focused on more specific emotional changes. Experiment 3 showed that, for Democrats, the intervention increased compassion. Experiment 4 showed that, for Republicans, the intervention reduced disgust, disapproval, anger, and contempt, but had no impact on compassion. For Democrats, but not for Republicans, reductions in animosity were mediated by reduced perceptions of control of self-formation, the mediator identified in prior work on historicist thinking and blame mitigation.</jats:p
