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1. Raman Spectroscopy and Modeling and Simulation of Quantum Dots and Nanomaterials for Optoelectronic and Sensing Applications

   https://doi.org/10.32604/icces.2024.013296  

   Misra, Prabhakar; Alghamdi, Hawazin; Garcia-Sanchez, Raul; Mitchell, Wyatt; Powell, Allison; Vohra, Nikhil (January 2024, The International Conference on Computational & Experimental Engineering and Sciences)

   Semiconducting quantum dots (Q-dots) with strain-tunable electronic properties are good contenders for quantum computing devices, as they hold promise to exhibit a high level of photon entanglement. The optical and electronic properties of Q-dots vary with their size, shape, and makeup. An assortment of Q-dots has been studied, including ZnO, ZnS, CdSe and perovskites [1]. We have employed both Raman spectroscopy (to precisely determine their vibrational frequencies) and UV-VIS spectroscopy (to determine accurately their band gap energies). The electronic band structure and density of states of the ZnO and ZnS Q-dots have been investigated under strain using Density Functional Theory (DFT). The computer program SIESTA (Spanish Initiative for Electronic Simulations with Thousands of Atoms) was used to perform the DFT calculations via the linear combination of atomic orbitals (LCAO) method. The spin polarization of such systems may itself be used to encode information or influence the electronic properties of semiconducting Q-dots, which deserve special attention, as they have potential applications in lasers, photovoltaic cells, and imaging. In addition, we have investigated pristine and functionalized graphene nanoplatelets and metal oxides for sensing applications. 

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2. Blockchains and Databases: Opportunities and Challenges for the Permissioned and the Permissionless

   https://doi.org/10.1007/978-3-030-54832-2_1  

   Agrawal, D.; El Abbadi, A.; Amiri, M.J.; Maiyya, S.; Zakhary, V. (August 2020, Advances in Databases and Information Systems)

   Darmont, J; Novikov, B.; Wrembel, R. (Ed.)

   Bitcoin [12] is a successful and interesting example of a global scale peer-to-peer cryptocurrency that integrates many techniques and protocols from cryptography, distributed systems, and databases. The main underlying data structure is blockchain, a scalable fully replicated structure that is shared among all participants and guarantees a consistent view of all user transactions by all participants in the system. In a blockchain, nodes agree on their shared states across a large network of untrusted participants. Although originally devised for cryptocurrencies, recent systems exploit its many unique features such as transparency, provenance, fault tolerance, and authenticity to support a wide range of distributed applications. Bitcoin and other cryptocurrencies use permissionless blockchains. In a permissionless blockchain, the network is public, and anyone can participate without a specific identity. Many other distributed applications, such as supply chain management and healthcare, are deployed on permissioned blockchains consisting of a set of known, identified nodes that still might not fully trust each other. This paper illustrates some of the main challenges and opportunities from a database perspective in the many novel and interesting application domains of blockchains. These opportunities are illustrated using various examples from recent research in both permissionless and permissioned blockchains. Two main themes unite the various examples: (1) the important role of distribution and consensus in managing large scale systems and (2) the need to tolerate malicious failures. The advent of cloud computing and large data centers shifted large scale data management infrastructures from centralized databases to distributed systems. One of the main challenges in designing distributed systems is the need for fault-tolerance. Cloud-based systems typically assume trusted infrastructures, since data centers are owned by the enterprises managing the data, and hence the design typically only assumes and tolerates crash failures. The advent of blockchain and the underlying premise that copies of the blockchain are distributed among untrusted entities has shifted the focus of fault-tolerance from tolerating crash failures to tolerating malicious failures. These interesting and challenging settings pose great opportunities for database researchers. 

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3. Public concerns and connected and automated vehicles: safety, privacy, and data security

   https://doi.org/10.1057/s41599-022-01110-x  

   Lee, Dasom; Hess, David J. (December 2022, Humanities and Social Sciences Communications)

   Abstract One dimension of the emerging politics of connected and automated vehicles (CAVs) is the development of public concerns over their societal implications and associated policy issues. This study uses original survey data from the United States to contribute to the anticipation of future policy and political issues for CAVs. Several studies have surveyed the public regarding CAVs; however, there are few studies that highlight the multidimensional public concerns that CAVs will most likely bring. The study breaks down the concept of “public” by showing that the demographic variables of gender, age, race, ethnicity, income, location (rural, suburban, urban), and political ideology (conservative, moderate, liberal) are significantly associated with three of the most salient public concerns to date (safety, privacy, and data security). Furthermore, the effects of demographic variables also vary across the type of policy issue. For example, women tend to be more concerned about safety than their male counterparts, and Hispanics (Latinx) tend to be more concerned about privacy than non-Hispanics. The research shows how the social scientific analysis of the “politics” of CAVs will require attention to the variegated connections between different types of public concern and different demographic variables. 

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4. Surfaces, silica and semivolatile organics—limonene uptake and desorption indoors and outdoors

   https://doi.org/10.1039/D5EM00275C  

   Reynolds, Ryan S; Johnson, Kristen N; Pacaud, Katelyn; Ezell, Michael; Lakey, Pascale_S J; Shiraiwa, Manabu; Finlayson-Pitts, Barbara J (July 2025, Environmental Science: Processes & Impacts)

   Adsorption of organics on surfaces is important in both outdoor and indoor environments. Surfaces can serve as sinks for gas-phase species, act as reservoirs by emitting previously partitioned organics back into the gas phase, and can facilitate heterogeneous chemistry. We report here studies of the uptake and desorption energetics of gas-phase limonene, a volatile and widely-distributed monoterpene, on solid silica nanoparticles using a unique apparatus that allows for temperature programmed desorption (TPD) measurements of surface binding energies as well as Knudsen cell gas uptake measurements. A multiphase kinetic model was applied to these data to provide additional molecular-level understanding of the processes involved. TPD experiments yielded an average desorption energy of 47.5 ± 8.2 kJ mol-1 (±1s, sample standard deviation), the first direct experimental measurement of this parameter over a broad temperature range (150–320 K). Initial net uptake coefficients (0,net) range from (1.7 ± 0.3) ×10-3 (±1s) at 210 K to (2.3 ± 0.4) ×10-4 (±1s) at 250 K, reflecting increased rates of desorption with an increase in temperature combined with increased rates of diffusion and re-adsorption within the pores between adjacent silica nanoparticles. Effective Langmuir constants, which also reflect the effects of pore diffusion and re-adsorption, were determined from the uptake data and vary from (1.8–0.3)×10-13 cm3 molecule-1 over the same temperature range. These results are in excellent agreement with previous studies around room temperature and with theoretical calculations of the energetics of the limonene-silica interaction. The strong attraction between limonene and the polar silica surface shows the importance of including such interactions in models of the atmospheric fates of terpenes both indoors and outdoors. 

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5. Geometry, analysis, and morphogenesis: Problems and prospects

   https://doi.org/10.1090/bull/1765  

   Lewicka, Marta; Mahadevan, L. (July 2022, Bulletin of the American Mathematical Society)

   The remarkable range of biological forms in and around us, such as the undulating shape of a leaf or flower in the garden, the coils in our gut, or the folds in our brain, raise a number of questions at the interface of biology, physics, and mathematics. How might these shapes be predicted, and how can they eventually be designed? We review our current understanding of this problem, which brings together analysis, geometry, and mechanics in the description of the morphogenesis of low-dimensional objects. Starting from the view that shape is the consequence of metric frustration in an ambient space, we examine the links between the classical Nash embedding problem and biological morphogenesis. Then, motivated by a range of experimental observations and numerical computations, we revisit known rigorous results on curvature-driven patterning of thin elastic films, especially the asymptotic behaviors of the solutions as the (scaled) thickness becomes vanishingly small and the local curvature can become large. Along the way, we discuss open problems that include those in mathematical modeling and analysis along with questions driven by the allure of being able to tame soft surfaces for applications in science and engineering. 

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