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HaptX Team Final Project Report
Get PDFA traditional haptic device utilizes motors to impose feedback motion constraints on a user interacting with it. However, primary concerns with human-robot interaction include safety, stability, and ease of manufacturing. It is therefore desired to develop a passive haptic device that users can interact with by moving the system along constrained single degree of freedom (SDOF) paths while restricting motion in other directions. The goal of the project is to develop a planar passive haptic system that can restrict motion paths while allowing only the prescribed SDOF paths.
The device is required to have at least six SDOF paths and force resistance capable of blocking the user when they deviate away from an SDOF path and preventing them from damaging the device. Additionally, the minimum angle between adjacent SDOF paths must be less than 90 degrees.
The design that we chose was a system of six linkages connected by brakes at each joint. These brakes are pneumatically powered and turn on and off to hold and release the motion of the linkages. Rotary encoders are mounted at the bottom of the brakes to track the relative position of the joints and the handle that is moved by the user. The primary requirements were that the system had at least 6 SDOF paths and could resist a maximum torque of 11Nm, produced by a user at the handle.
To test that the device matched the characteristics and requirements that it was designed, the assembled prototype was subject to many tests, as well as virtual simulations. Some requirements and constraints were achieved simply by nature of the design. For example, the six SDOF paths are inherently included in the design by the addition of 6 brakes, and therefore it does not need to be confirmed through testing. However, some tests were performed to test the functionality, including both angle measurement and force testing for one linkage, as well as the full system. In addition, MATLAB simulations verified the angle change between the different degrees of freedom paths. Each of these tests verified different parts of the requirements. All of these tests were successful.
There are no major modifications that need to be made to the device moving forward. All requirements for design have been met. However, there are modifications that should be made to increase the ability and accuracy of the device. Currently there is too much slack in the joints that will not only affect force, but position measurements as well. This issue should be address to improve the device
Supported Ni-Au Colloid Precursors for Active, Selective, and Stable Alkyne Partial Hydrogenation Catalysts
No full textBimetallic NiAu catalysts have garnered broad interest for a variety of reactions including automotive emissions, selective hydrogenation, selective oxidation, hydrodechlorination, and biomass conversion. However, the bulk immiscibility of the two metals, complicating catalyst synthesis, has limited studies of this bimetallic system. We report a solution-phase synthesis for Ni and bimetallic NiAu heterogeneous catalysts. Using oleylamine as a capping agent, an optimized synthesis for Ni catalysts led to supported particles with a narrow size distribution (4.7 ± 0.4 nm). Gold was added to the Ni nanoparticles via galvanic displacement of Ni in organic solution, the particles were deposited onto commercial alumina, and oleylamine capping agent was removed. The catalytic activity of the bimetallic materials in 1-octyne partial hydrogenation was in between the activity of monometallic Ni and Au catalysts. At high space velocity, the bimetallic catalysts largely maintained the high alkene selectivity associated with Au catalysts (\u3e90% alkene selectivity at a 95% conversion). At lower space velocities, the NiAu catalysts also had a reduced propensity to overhydrogenate the alkene (relative to Ni). A simple catalyst performance parameter, which combined activity, selectivity, and space velocity, was developed and used to describe the overall performance of each catalyst under varying reaction conditions. By this metric, the bimetallic catalysts had considerably better performance than monometallic Ni. The most active bimetallic catalyst was examined with a week-long stability test; it showed no activity loss with a 100% carbon balance. Catalysts were characterized by transmission electron microscopy, X-ray diffraction, H2 and N2 adsorption, and inductively coupled plasma-optical emission spectroscopy (ICP-OES). The reactivity and characterization studies suggest the active catalysts are likely composed of bimetallic NiAu surfaces. The incorporation of Au into the catalysts suppresses H2 adsorption on Ni, leading to lower hydrogen coverage during catalysis; this contributes to slowing undesirable alkene hydrogenation and improving catalyst selectivity
Pharmacologic IRE1/XBP1s Activation Confers Targeted ER Proteostasis Reprogramming
Get PDFActivation of the IRE1/XBP1s signaling arm of the unfolded protein response (UPR) is a promising strategy to correct defects in endoplasmic reticulum (ER) proteostasis implicated in diverse diseases. However, no pharmacologic activators of this pathway identified to date are suitable for ER proteostasis remodeling through selective activation of IRE1/XBP1s signaling. Here, we use high-throughput screening to identify non-toxic compounds that induce ER proteostasis remodeling through IRE1/XBP1s activation. We employ transcriptional profiling to stringently confirm that our prioritized compounds selectively activate IRE1/XBP1s signaling without activating other cellular stress-responsive signaling pathways. Furthermore, we demonstrate that our compounds improve ER proteostasis of destabilized variants of amyloid precursor protein (APP) through an IRE1-dependent mechanism and reduce APP-associated mitochondrial toxicity in cellular models. These results establish highly selective IRE1/XBP1s activating compounds that can be widely employed to define the functional importance of IRE1/XBP1s activity for ER proteostasis regulation in the context of health and disease. [Figure not available: see fulltext.]
Controls on Carbonate Platform Architecture and Reef Recovery Across the Palaeozoic to Mesozoic Transition: A High-Resolution Analysis of the Great Bank of Guizhou
No full textCarbonate platforms spanning intervals of global change provide an opportunity to identify causal links between the evolution of marine environment and depositional architecture. This study investigates the controls on platform geometry across the Palaeozoic to Mesozoic transition and yields new stratigraphic and palaeoenvironmental constraints on the Great Bank of Guizhou, a latest Permian to earliest Late Triassic isolated carbonate platform in the Nanpanjiang Basin of south China. Reconstruction of platform architecture was achieved by integrating field mapping, petrography, biostratigraphy, satellite imagery analysis and δ13C chemostratigraphy. In contrast to previous interpretations, this study indicates that: (i) the Great Bank of Guizhou transitioned during Early Triassic time from a low-relief bank to a platform with high relief above the basin floor (up to 600 m) and steep slope angles (preserved up to 50°); and (ii) the oldest-known platform-margin reef of the Mesozoic Era grew along steep, prograding clinoforms in an outer-margin to lower-slope environment. Increasing platform relief during Early Triassic time was caused by limited sediment delivery to the basin margin and a high rate of accommodation creation driven by Indosinian convergence. The steep upper Olenekian (upper Lower Triassic) slope is dominated by well-cemented grainstone, suggesting that high carbonate saturation states led to syndepositional or rapid post-depositional sediment stabilization. Latest Spathian reef initiation coincided with global cooling following Early Triassic global warmth. The first Triassic framework-building metazoans on the Great Bank of Guizhou were small calcareous sponges restricted to deeper water settings, but early Mesozoic reef builders were volumetrically dominated by Tubiphytes, a fossil genus of uncertain taxonomic affinity. In aggregate, the stratigraphic architecture of the Great Bank of Guizhou records sedimentary response to long-term environmental and biological recovery from the end-Permian mass extinction, highlighting the close connections among marine chemistry, marine ecosystems and carbonate depositional systems
From the Cinema to Beyond: Homer in Comics, Television, Apps, and New Media
No full textThe last twenty-five years have seen many new forms of Homeric reception, including those in comics, video and board games, and animé
Reading the Myth of American Freedom: The U.S. Immigration Video
Get PDFThe U.S. Citizenship and Immigration Services (USCIS) department offers immigrants wishing to naturalize, or become citizens, a package of study aids for the citizenship test, including a video. This essay argues that the video is much more than a study aid; it furthers the myth of American freedom, a myth that effectively erases the struggles of marginalized groups. Situated within critical cultural studies and semiotics, the essay describes the content of the video and interprets the myth. The deployment of diversity is considered, along with implications for immigrants who intersect with some of the marginalized or absent groups
Thermal Performance of Helical Coils with Reversed Loops and Wire Coil Inserts
No full textFlow and heat transfer characteristics of water in a newly designed helical coil heat transfer device were investigated in this experimental study. The conventional helical coil configuration was structurally modified aiming to improve its heat transfer performance. Specifically, 360° plastic tubing with or without wire coil inserts was added after each 180° of the main helical coil loop to enhance fluid mixing and redistribute the flow, which should have a direct effect on the thermal performance of the helical coil heat transfer device. Experimental results show that the structural modifications of the conventional helical coil configuration led to enhanced heat transfer in the test section while the pressure drop penalty increased slightly. Furthermore, the heat transfer performance of the overall test section improved by using wire coil inserts in the plastic tubing after every 180° of the main helical coil loop. The results reveal that the modified helical coil section offers a good trade-off between heat transfer enhancement and pressure drop penalty
Fully Automated Carbonate Petrography Using Deep Convolutional Neural Networks
No full textCarbonate rocks are important archives of past ocean conditions as well as hosts of economic resources such as hydrocarbons, water, and minerals. Geologists typically perform compositional analysis of grain, matrix, cement and pore types in order to interpret depositional environments, diagenetic modification, and reservoir quality of carbonate strata. Such information can be obtained primarily from petrographic analysis, a task that is costly, labor-intensive, and requires in-depth knowledge of carbonate petrology and micropaleontology. Recent studies have leveraged machine learning-based image analysis, including Deep Convolutional Neural Networks (DCNN), to automate description, classification and interpretation of thin sections, subsurface core images and seismic facies, which would accelerate data acquisition and reproducibility for these tasks. In carbonate rocks, this approach has been applied primarily to recognize carbonate lithofacies, and no attempt has been made to individually identify and quantify various types of carbonate grains, matrix, and cement. In this study, the applicability and performance of DCNN-based object detection and image classification approaches are assessed with respect to carbonate compositional analysis. The training data comprised of more than 13,000 individually labelled objects from nearly 4000 carbonate petrographic images. The dataset is grouped into six and nine different classes for the image classification and object detection tasks, respectively. Even with a small and relatively imbalanced training set, the DCNN was able to achieve an F1 score of 92% for image classification and 84% mean precision for object detection by combining one-cycle policy, class weight, and label mixup-smoothing methods. This study highlights the inefficiency of image classification as an approach to replicating human description and classification of carbonate petrography. By contrast, DCNN-based object detection appears capable of approaching human speed and accuracy in the area of carbonate petrography because it is able to individually locate and identify different carbonate components with greater cost-efficiency, speed, and reproducibility than conventional (human) petrographic analysis
Sequence Predictive Recognition of Proteins and Peptides by Synthetic and Natural Receptors
No full textThe highly sequence-selective molecular recognition of proteins and peptides in Nature inspires and informs the development of synthetic receptors to mimic, measure, and modulate these processes. This chapter focuses on the cucurbit[n]urils, which have been particularly powerful in this regard. We describe the discovery and elaboration of the sequence-selective recognition of peptides by cucurbit[n]urils. In addition, we overview the development of this supramolecular chemistry into myriad applications and the extension to protein recognition. Finally, we compare the binding properties of synthetic receptors with those of natural N-recognins, proteases, and other sequence-selective protein receptors. The strong correlation between natural and synthetic receptors in their molecular basis for sequence recognition should serve to improve the design of next-generation compounds
Structure and Unprecedented Reactivity of a Mononuclear Nonheme Cobalt(III) Iodosylbenzene Complex
Get PDFA mononuclear nonheme cobalt(III) iodosylbenzene complex, [CoIII(TQA)(OIPh)(OH)]2+ (1), is synthesized and characterized structurally and spectroscopically. While 1 is a sluggish oxidant in oxidation reactions, it becomes a competent oxidant in oxygen atom transfer reactions, such as olefin epoxidation, in the presence of a small amount of proton. More interestingly, 1 shows a nucleophilic reactivity in aldehyde deformylation reaction, demonstrating that 1 has an amphoteric reactivity. Another interesting observation is that 1 can be used as an oxygen atom donor in the generation of high-valent metal-oxo complexes. To our knowledge, we present the first crystal structure of a CoIII iodosylbenzene complex and the unprecedented reactivity of metal-iodosylarene adduct