1,299 research outputs found
Beyond biotemplating: multiscale porous inorganic materials with high catalytic efficiency
No full textBiotemplating makes it possible to prepare materials with complex structures by taking advantage of nature's ability to generate unique morphologies. In this work, we designed and produced a multi-scale porosity (MSP) scaffold starting from sea urchin spines by adding an additional nano-porosity to its native micro-porosity. The final replica shows porosity in both length scales and is an effective high-performing photocatalytic material
04-08 Under the Fig Tree: From Judaism to Lutheranism with Sam Aizenberg
No full textIn this episode of Under the Fig Tree, hosts Rev. Micah Glenn and Dr. Ben Haupt chat with Sam Aizenberg, a fourth-year Master of Divinity student. Raised by a Jewish father and Southern Baptist mother, Sam took a long and winding road to Lutheranism. After being raised in the Conservative Jewish faith, he attended Faith Lutheran High School in Las Vegas, where he was first exposed to Lutheran doctrine and beliefs. After attending a nondenominational Christian church for several years, he eventually started attending a Lutheran church as an undergraduate. “The first time I went in there, the Lutheran church, it was like drinking water for the first time in four or five years,” he recalls. “The people were so kind and friendly but really that feeling of having that thirst quenched, that great spiritual thirst, was during the sermon. It felt like home.” Sam also shares why his vicarage year was the “very best year” and offers some advice for prospective students. “You don’t need to compare yourself to others and where you come from,” he says. “I think some people think, ‘Wow, I need to have some incredible story,’ or ‘I need to be the ninth generation or something.’ No, if you want to pursue church work, go for it. … Just come and be willing to be formed. God will use you in the capacity that He’s going to. Remember, you’re not the gift to the church. The church is Christ’s gift to you.
“Under the Fig Tree” is a video and audio podcast of Concordia Seminary, St. Louis. New video and audio episodes are added weekly each Monday during the academic year. “Under the Fig Tree” can be found on YouTube, the Seminary’s Scholar site (scholar.csl.edu) and most podcast platforms including Spotify, Apple Podcasts and Google Podcasts. Those interested in vocational ministry are invited to join the Seminary contact list at Request-Information. You can learn more about Concordia Seminary at csl.edu or by contacting the admissions team at [email protected] or 800-822-9545
Directional wetting in anisotropic inverse opals
No full textPorous materials display interesting transport phenomena due to the restricted motion of fluids within the nano- to micro-scale voids. Here, we investigate how liquid wetting in highly ordered inverse opals is affected by anisotropy in pore geometry. We compare samples with different degrees of pore asphericity and find different wetting patterns depending on the pore shape. Highly anisotropic structures are infiltrated more easily than their isotropic counterparts. Further, the wetting of anisotropic inverse opals is directional, with liquids filling from the side more easily. This effect is supported by percolation simulations as well as direct observations of wetting using time-resolved optical microscopy
The Ethics of AI in Human Resources
No full textGreen Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Cyber Securit
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Raspberry-colloid-templated catalysts as a model thermocatalytic platform
No full textNanoparticle (NP)-supported catalysts are critical to the industrial production of over 90% of the chemicals and raw materials used today. Their catalytic performance is predicated on a combination of geometric and electronic descriptors associated with the properties of the NPs, support, and the (NP–support) interactions between them. However, existing catalyst preparative methods of nucleating and/or immobilizing NPs on support surfaces do not permit independent variation of NP or support properties as NP nucleation and growth characteristics are dependent on the support chemistry and vice versa. Consequently, such interconnected material properties cannot enable systematic investigations whereby individual NP or support properties are independently tuned to elucidate unambiguous and valuable structure–property relationships to guide future catalyst designs. Separately, this challenge is also exacerbated under thermocatalytic reaction conditions of high temperature, pressure, and mechanical agitation, which accelerates NP sintering and uncontrolled NP size growth, further confounding catalytic analyses. An effective model catalytic platform for fundamental structure–property studies should thus possess two pre-requisites: independent tunability of structural properties (NP and support) and high thermomechanical stability to preserve these as-synthesized structural properties under typical reaction conditions.
To address this gap, I adapted the raspberry-colloid-templating (RCT) strategy previously developed by the Aizenberg group. In Chapter 1, I outline the RCT synthetic methodology and highlight two key design features: partial NP entrenchment into the support which confers enhanced catalytic stability against NP sintering, and synthetic modularity for independent combinatorial variations of the catalyst’s building blocks and their spatial organization from the nanoscale to macroscale. These two unique features yield thermomechanically stable RCT catalysts with numerous degrees of freedom to isolate and independently tune potential catalytic descriptors, thereby facilitating unambiguous studies to derive newfound structure–property relationships that guide future catalyst designs.
In the rest of this dissertation, I describe how I leveraged on these two key design features to employ the RCT strategy as a well-defined and synthetically robust model thermocatalytic platform to elucidate important structural insights into catalyst design that cannot be easily achieved using traditional catalyst preparation methods. Specifically, I highlight my investigations into three structural features found in practically all NP-supported catalysts: properties of NP ensembles as a collective entity, NP–support interfaces, and individual NP properties. First, I demonstrate how using pre-formed colloidal NPs, in combination with the synthetic decoupling of the NP and support formation steps in the RCT method, disentangle the effects of NP proximity (Chapter 2), a collective NP ensemble property, from the effects of NP size (Chapter 3), to independently tune catalytic activity and selectivity, respectively. Second, I illustrate how the support chemistry and NP embedding effects can be deconvoluted to accentuate catalytic contributions arising from NP–support interfacial sites (Chapter 4), while also revealing nanoscale wetting phenomena at the interface that I subsequently exploited to direct bimetallic catalyst synthesis (Chapter 5). Third, I show how the RCT method can be applied to isolate individual NP properties from (all) other potential structural descriptors to facilitate systematic evaluations into individual NPs properties. This point is exemplified through separate studies into nanoscale effects of the surface Pd ensemble sizes in dilute Pd-in-Au alloyed NPs on competitive reactant adsorption energetics (Chapter 6), and distinguishing the surface- and vapor-mediated sintering pathways of Pt and Pd diesel oxidation catalysts (Chapter 7). Finally, I summarize my work, provide an outlook on the RCT catalyst platform, and discuss future opportunities, challenges, and applications (Chapter 8).Chemistry and Chemical Biolog
Computer-Aided Comparative Assessment of Inflammatory Lesions in MRI of the Spine in Axial Spondyloarthritis Patients
No full textDetection of inflammatory lesions in magnetic resonance imaging (MRI) of the spine in axial Spondyloarthritis (SpA) patients is a labor-intensive task. Current scoring methods often require an expert reader to visually assess 23 vertebral units (VU) on multiple MRI slices. Furthermore, monitoring of progressive changes consists of a manual search and alignment of the 23 VUs in both baseline and follow-up scans, followed by side-by-side comparison of two images. We present a semi-automated framework for comparative visualization of inflammatory lesions in MRI of the spine in axial SpA patients. The first part of our method localizes and segments the VUs using a fully automatic algorithm based on quasi-periodicity of vertebral column intensity profile and tissue class probability maps. The second part uses these segmentations to align baseline and follow-up scans by deriving a locally rigid transform from a pre-computed deformable registration. To facilitate visual comparison, the co-registered baseline and follow-up images are fused in a single color-encoded difference image. This allows an expert reader to efficiently interpret progressive changes while focusing on just one image. Experiments in which an expert reader used the proposed framework to score inflammatory changes in axial SpA patients were performed. Results showed strong agreement with ground truth scores for cases of full lesion occurrence/remission.Signals & SystemsIntelligent SystemsElectrical Engineering, Mathematics and Computer Scienc
Exchange Rates and the Price Level in the Socialist Economy
No full textA change in the gold content of the ruble and in its exchange rate took place on January 1, 1961. The gold content of the ruble was set at 0.987412 grams of pure gold, and its exchange rate at 90 kopecks to the American dollar, replacing the gold content of 0.222168 grams and a four-ruble exchange rate set in 1950. The price of gold purchased by the USSR State Bank was set at one ruble per gram.
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