Direct Modeling: Easy Changes in CAD?

Direct Modeling is an emerging CAD technology that uses direct manipulation of the geometry to effect changes in the part model, and is based on a boundary representation database. This paper highlights the differences between Direct Modeling and conventional history-based solid modeling, compares emerging technologies, and discusses what this means for engineering graphics educators

Innovations in (U–Th)/He, Fission Track, and Trapped Charge Thermochronometry with Applications to Earthquakes, Weathering, Surface‐Mantle Connections, and the Growth and Decay of Mountains

A transformative advance in Earth science is the development of low‐temperature thermochronometry to date Earth surface processes or quantify the thermal evolution of rocks through time. Grand challenges and new directions in low‐temperature thermochronometry involve pushing the boundaries of these techniques to decipher thermal histories operative over seconds to hundreds of millions of years, in recent or deep geologic time and from the perspective of atoms to mountain belts. Here we highlight innovation in bedrock and detrital fission track, (U–Th)/He, and trapped charge thermochronometry, as well as thermal history modeling that enable fresh perspectives on Earth science problems. These developments connect low‐temperature thermochronometry tools with new users across Earth science disciplines to enable transdisciplinary research. Method advances include radiation damage and crystal chemistry influences on fission track and (U–Th)/He systematics, atomistic calculations of He diffusion, measurement protocols and numerical modeling routines in trapped charge systematics, development of 4He/3He and new (U–Th)/He thermochronometers, and multimethod approaches. New applications leverage method developments and include quantifying landscape evolution at variable temporal scales, changes to Earth\u27s surface in deep geologic time and connections to mantle processes, the spectrum of fault processes from paleoearthquakes to slow slip and fluid flow, and paleoclimate and past critical zone evolution. These research avenues have societal implications for modern climate change, groundwater flow paths, mineral resource and petroleum systems science, and earthquake hazards

Modelling the relationships of internal governance mechanisms on innovation: empirical insight from utility tokens

The purpose of this paper is to determine the impact internal corporate governance mechanisms have on innovation. Current studies are inconclusive on the conceptual relationship given the wide range of institutions that influence corporate governance in countries around the world. This paper examines the impact of ownership structure and advisory board structure on innovation output in the context of utility tokens, which is an idyllic setting as there are no notable regulations that apply to utility token offerings as contracts are enforced through smart contracts, on blockchain, thus serving as a fruitful laboratory for exploring the conceptual relationships. The analyses were conducted on 525 utility tokens, which held their initial offerings within a period of three years. Several linear regressions were conducted, with the natural logarithm of pull requests merged on GitHub files as the dependent variable, representing innovation output. The percentage of token supply owned by whales represented ownership concentration, the number of institutional owners represented institutional ownership and advisory boards size and technical intensity represented advisory board structure. To test potential quadratic relationships, the squared terms of each independent variable was also considered. Findings suggest that ownership concentration, represented by the percentage owned by whales, has a quadratic, inverse-U relationship on innovation output, which may reconcile the positive and negative linear findings from prior research. Institutional ownership had a strong, positive relationship on innovation output. In this context, institutions were all venture capital firms and this advances knowledge as venture capital firms have not been isolated from other institutional investors in prior research due to difficulty with access to data. The findings also cemented predictions for advisory board structure, namely that the technical intensity of the advisory board explained more variance for innovation outcomes than the raw number of advisors. This is the first study to empirically examine advisory boards of organizations. The main contribution of this research is the modelling of conceptual relationships between governance and innovation in a context without much formal institutional forces influencing governance, and the testing of quadratic instead of strictly linear relationships. This research concludes with discussions of its limitations, implications for governance regulatory bodies and investors and methodological contributions on using the utility token environment as a laboratory for testing governance relationships

Cam Design Projects in an Advanced CAD Course for Mechanical Engineers

The objective of this paper is to present applications of solid modeling aimed at modeling of complex geometries such as splines and blended surfaces in advanced CAD courses. These projects, in CAD-based Mechanical Engineering courses, are focused on the use of the CAD system to solve design problems for applications in machine design, namely the geometric and mechanical design of cam mechanisms

Message from the Chair

As I sit down to write this message, the spring sunshine is pouring through my window after a long, cold winter. Each year we have this wonderful time of new beginnings. By the time you read this message, the Engineering Design Graphics Division will have installed its new slate of officers, and they will begin their work to carry out the mission of the division. I will hand over the gavel of leadership to Ron Paré, assisted as vice chair by Ted Branoff. Our new director of Technical and Professional, Nate Hartman, and Director of Zones, Pat Connolly, bring their enthusiasm to those committees. I hope that you will all give them your utmost support along with the other officers of the division as we work together to strengthen our membership and strive towards educating our students in Engineering Graphics.   Springtime is also a time of endings in our academic year, as we wrap up our courses and say goodbye to our graduating seniors, so too, I say goodbye to you as your division chair. I would like to thank all of the officers who have worked so hard to keep the division going. There are many active members in addition to the elected officers, and so I will not mention them all individually, but I want you all to know that I deeply appreciate your commitment to the division. I look forward to seeing you all at the annual meeting in Portland, and the midyear meeting in Fort Lauderdale.   I say goodbye to you as your division chair. I would like to thank all of the officers who have worked so hard to keep the division going

Hematite (U-Th)/He Thermochronometry Detects Asperity Flash Heating During Laboratory Earthquakes

Evidence for coseismic temperature rise that induces dynamic weakening is challenging to directly observe and quantify in natural and experimental fault rocks. Hematite (U-Th)/He (hematite He) thermochronometry may serve as a fault-slip thermometer, sensitive to transient high temperatures associated with earthquakes. We test this hypothesis with hematite deformation experiments at seismic slip rates, using a rotary-shear geometry with an annular ring of silicon carbide (SiC) sliding against a specular hematite slab. Hematite is characterized before and after sliding via textural and hematite He analyses to quantify He loss over variable experimental conditions. Experiments yield slip surfaces localized in an ∼5–30-µm-thick layer of hematite gouge with71% ± 1% (1σ) and 18% ± 3% He loss, respectively. Documented He loss requires short-duration, high temperatures during slip. The spatial heterogeneity and enhanced He loss from FM zones are consistent with asperity flash heating (AFH). Asperities \u3e200–300 µm in diameter, producing temperatures \u3e900 °C for ∼1 ms, can explain observed He loss. Results provide new empirical evidence describing AFH and the role of coseismic temperature rise in FM formation. Hematite He thermochronometry can detect AFH and thus seismicity on natural FMs and other thin slip surfaces in the upper seismogenic zone of Earth’s crust

Excitatory amino acids and intracellular pH in motoneurons of the isolated frog spinal cord

Double-barrelled pH-sensitive micro-electrodes were used to measure changes of intracellular and extracellular pH in and around motoneurons of the isolated frog spinal cord during application of excitatory amino acids. It was found that N-methyl- -aspartate, quisqualate and kainate produced a concentration-dependent intracellular acidification. Extracellularly, triphasic pH changes (acid-alkaline-acid going pH transients) were observed during the action of these amino acids. The possible significance of such pH changes for the physiological and pathophysiological effects of excitatory amino acids are discussed

Genetic comparison of water molds from embryos of amphibians Rana cascadae, Bufo boreas and Pseudacris regilla

Water molds that cause the disease saprolegniasis have been implicated in widespread mortality of amphibian embryos. However, because of the limitations of traditional identification methods, water mold species involved in die-offs or utilized in ecological studies often remain unidentified or identified only as Saprolegnia ferax. Furthermore, water mold taxonomy requires revision, so very distinct organisms may all be called S. ferax. Recent DNA-based studies indicate that the diversity of water molds infecting amphibian embryos is significantly higher than what was previously known, but these studies rely on culture methods, which may be biased towards taxa that grow best under laboratory conditions. In this study, total embryo-associated DNA was extracted from 3 amphibian species in a pond in central Washington, USA. The internal transcribed spacer (ITS) region of DNA was amplified with primers capable of amplifying a broad array of eukaryotic microorgansisms, and was used to construct clone libraries. Individual clones were sequenced and relationships among newly recovered sequences and previously studied taxa were analyzed using phylogenetics. These methods recovered several new taxa in association with amphibian embryos. Samples grouped into 11 distinct phylotypes with ITS sequence differences ranging from 4 to 28%. The water mold communities recovered differed among Rana cascadae, Bufo boreas, and Pseudacris regilla egg masses. Furthermore, the diversity of water molds increased as egg masses aged, and members comprising this diversity changed over time

The Formal Institutional Context of Informal Entrepreneurship: A Cross-National, Configurational-Based Perspective

While previous comparative research has identified the formal institutional conditions that differentiate countries on their degree of informal entrepreneurship, this paper examines the characteristics that shape cross-national diversity in its type. Based on a series of fuzzy-set qualitative comparative analyses (fs/QCA) of 138 country cases, we find evidence of causal heterogeneity in the configuration of institutional conditions associated with entrepreneurial outcomes that are informal and growth-oriented and those that are informal and subsistence-oriented. Given our results, we propose that the formal institutional-based conditions that differentiate between types of informal sectors are best identified by the conjoint mixture of strength and weakness of state capabilities across multiple domains, rather than by uniform weakness, or voids, along all state functions. In our discussion, we explore the implication of our configurational-based findings for the comparative analysis of national systems of informal entrepreneurship and for the tailoring of policies to account for the multiple institutional-based pathways by which entrepreneurs come to enter into the informal economy

Use of Technology Solutions to Improve CAD Instruction

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