Level-of-detail for cognitive real-time characters

We present a solution for the real-time simulation of artificial environments containing cognitive and hierarchically organized agents at constant rendering framerates. We introduce a level-of-detail concept to behavioral modeling, where agents populating the world can be both reactive and proactive. The disposable time per rendered frame for behavioral simulation is variable and determines the complexity of the presented behavior. A special scheduling algorithm distributes this time to the agents depending on their level-of-detail such that visible and nearby agents get more time than invisible or distant agents. This allows for smooth transitions between reactive and proactive behavior. The time available per agent influences the proactive behavior, which becomes more sophisticated because it can spend time anticipating future situations. Additionally, we exploit the use of hierarchies within groups of agents that allow for different levels of control. We show that our approach is well-suited for simulating environments with up to several hundred agents with reasonable response times and the behavior adapts to the current viewpoin

Simultaneous formation of ferrite nanocrystals and deposition of thin films via a microwave-assisted nonaqueous sol-gel process

Combination of the surfactant-free nonaqueous sol-gel approach with the microwave technique makes it possible to synthesize Fe3O4, CoFe2O4, MnFe2O4, and NiFe2O4 nanoparticles of about 5-6nm and with high crystallinity and good morphological uniformity. The synthesis involves the reaction of metal acetates or acetylacetonates as precursors with benzyl alcohol at 170°C under microwave irradiation of 12min. Immersion of glass substrates in the reaction solution results in the deposition of homogeneous metal ferrite films whose thickness can be adjusted through the precursor concentration. If preformed nickel nanoparticles are used as a type of curved substrate, the ferrite nanoparticles coat the seeds and form core-shell structures. These results extend the microwave-assisted nonaqueous sol-gel approach beyond the simple synthesis of nanoparticles to the preparation of thin films on flat or curved substrate

Transparent conducting Sn:ZnO films deposited from nanoparticles

Homogeneous transparent conducting Sn:ZnO films on fused silica substrates were prepared by dip-coating from nanoparticle dispersions, while the nanocrystalline Sn:ZnO particles with different dopant concentrations were synthesized by microwave-assisted non-aqueous sol-gel process using Sn(IV) tert-butoxide and Zn(II) acetate as precursors and benzyl alcohol as solvent. The dopant concentration had a great impact on the electrical properties of the films. A minimum resistivity of 20.3Ωcm was obtained for a porous Sn:ZnO film with initial Sn concentration of 7.5mol% after annealing in air and post-annealing in N2 at 600°C. The resistivity of this porous film could further be reduced to 2.6 and 0.6Ωcm after densified in Sn:ZnO and Al:ZnO reaction solution, respectively. The average optical transmittance of a 400-nm-thick Sn:ZnO film densified with Sn:ZnO after the two annealing steps was 91

Microwave-Assisted Nonaqueous Sol–Gel Deposition of Different Spinel Ferrites and Barium Titanate Perovskite Thin Films

Rapid and selective heating of solvents by microwave irradiation coupled to nonaqueous sol–gel chemistry makes it possible to simultaneously synthesize metal oxide nanoparticles within minutes and deposit them on substrates. The simple immersion of substrates, such as glass slides, in the reaction solution results after microwave heating in the deposition of homogeneous porous thin films whose thickness can be adjusted through the precursor concentration. Here we use such a microwave-assisted nonaqueous sol–gel process for the formation of various spinel ferrite MFe2O4 (M = Fe, Co, Mn, Ni) and BaTiO3 nanoparticles and their deposition as thin films. The approach offers high flexibility with respect to controlling the crystal size by adjusting the reaction time and/or temperature. Based on the example of CoFe2O4 nanoparticles, we show how the crystal size can carefully be tuned from 4 to 8 nm, resulting in a continuous change of the magnetic properties

Bottom-Up Design of a Green and Transient Zinc-Ion Battery with Ultralong Lifespan

Transient batteries are expected to lessen the inherent environmental impact of traditional batteries that rely on toxic and critical raw materials. This work presents the bottom-up design of a fully transient Zn-ion battery (ZIB) made of nontoxic and earth-abundant elements, including a novel hydrogel electrolyte prepared by cross-linking agarose and carboxymethyl cellulose. Facilitated by a high ionic conductivity and a high positive zinc-ion species transference number, the optimized hydrogel electrolyte enables stable cycling of the Zn anode with a lifespan extending over 8500 h for 0.25 mA cm−2 – 0.25 mAh cm−2. On pairing with a biocompatible organic polydopamine-based cathode, the full cell ZIB delivers a capacity of 196 mAh g−1 after 1000 cycles at a current density of 0.5 A g−1 and a capacity of 110 mAh g−1 after 10 000 cycles at a current density of 1 A g−1. A transient ZIB with a biodegradable agarose casing displays an open circuit voltage of 1.123 V and provides a specific capacity of 157 mAh g−1 after 200 cycles at a current density of 50 mA g−1. After completing its service life, the battery can disintegrate under composting conditions.The authors gratefully acknowledge financial support from ETH Zurich (ETH Research Grant ETH-45 18-1) and from the Global Training program of the Basque Government. Financial support from the “2021 Euskampus Missions 1.0. Programme” granted by Euskampus Fundazioa is acknowledged. D.K. acknowledges the UNSW for the support through the academic start-up grant. Xavier Aeby from Cellulose and Wood Materials Laboratory, EMPA, is thanked for his support in the degradation experiments. The authors also acknowledge support from the Scientific Center for Optical and Electron Microscopy (ScopeM) of ETH Zurich

Transient Rechargeable Battery with a High Lithium Transport Number Cellulosic Separator

Transient batteries play a pivotal role in the development of fully autonomous transient devices, which are designed to degrade after a period of stable operation. Here, a new transient separator-electrolyte pair is introduced for lithium ion batteries. Cellulose nanocrystals (CNCs) are selectively located onto the nanopores of polyvinyl alcohol membranes, providing mobile ions to interact with the liquid electrolyte. After lithiation of CNCs, membranes with electrolyte uptake of 510 wt%, ionic conductivities of 3.077 mS center dot cm(-1), electrochemical stability of 5.5 V versus Li/Li+, and high Li+ transport numbers are achieved. Using an organic electrolyte, the separators enable stable Li metal deposition with no dendrite growth, delivering 94 mAh center dot g(-1) in Li/LiFePO4 cells at 100 mA center dot g(-1) after 200 cycles. To make the separator-electrolyte pair transient and non-toxic, the organic electrolyte is replaced by a biocompatible ionic liquid. As a proof of concept, a fully transient Li/V2O5 cell is assembled, delivering 55 mAh center dot g(-1) after 200 cycles at 100 mA center dot g(-1). Thanks to the reversible Li plating/stripping, dendrite growth suppression, capacity retention, and degradability, these materials hold a bright future in the uptake of circular economy concepts applied to the energy storage field.The authors gratefully acknowledge financial support from ETH Zurich (ETH Research Grant ETH-45 18-1). The authors thank Medicell Membranes Ltd. for kindly providing Visking dialysis membranes. The authors acknowledge support from the Scientific Center for Optical and Electron Microscopy (ScopeM) of ETH Zurich. The authors also thank Dr. Dipan Kundu for helpful discussions on transport number

Simultaneous formation of ferrite nanocrystals and deposition of thin films via a microwave-assisted nonaqueous sol-gel process

Combination of the surfactant-free nonaqueous sol-gel approach with the microwave technique makes it possible to synthesize Fe3O4, CoFe2O4, MnFe2O4, and NiFe 2O4 nanoparticles of about 5-6 nm and with high crystallinity and good morphological uniformity. The synthesis involves the reaction of metal acetates or acetylacetonates as precursors with benzyl alcohol at 170 °C under microwave irradiation of 12 min. Immersion of glass substrates in the reaction solution results in the deposition of homogeneous metal ferrite films whose thickness can be adjusted through the precursor concentration. If preformed nickel nanoparticles are used as a type of curved substrate, the ferrite nanoparticles coat the seeds and form core-shell structures. These results extend the microwave-assisted nonaqueous sol-gel approach beyond the simple synthesis of nanoparticles to the preparation of thin films on flat or curved substrates. © 2010 Springer Science+Business Media, LLC

Anatase-silica composite aerogels: a nanoparticle-based approach

Herein we present the synthesis of anatase-silica aerogels based on the controlled gelation of preformed nanoparticle mixtures. The monolithic aerogels with macroscopic dimensions show large specific surface areas, and high and uniform porosities. The major advantage of such a particle-based approach is the great flexibility in pre-defining the compositional and structural features of the final aerogels before the gelation process by fine-tuning the properties of the titania and silica building blocks (e.g., size, composition and crystallinity) and their relative ratio in the dispersion. Specific surface functionalization enables control over the interaction between the nanoparticles and thus over their distribution in the aerogel. Positively charged titania nanoparticles are co-assembled with negatively charged Stoeber particles, resulting in a binary aerogel with a crystalline anatase and amorphous silica framework directly after supercritical drying without any calcination step. Titania-silica aerogels combine the photocatalytic activity of the anatase nanoparticles with the extensive silica chemistry available for silica surface functionalization

Stiffness-Dependent Intracellular Location of Cylindrical Polymer Brushes

Cylindrical polymer brushes (CPBs) are macromolecules with nanoparticle proportions. Their modular synthesis enables tailoring of their chemical composition as well as the dialing-up of overall dimensions and physicochemical properties. In this study, two rod-like poly[(ethylene glycol) methyl ether methacrylate] (PEGMA)-based CPBs with varying stiffness but otherwise comparable features and functionality, are synthesized. Differences in particle stiffness are assessed using small angle neutron scattering (SANS). It is observed that the fate of the two CPBs within cells is distinctly different. Stiffer CPBs seem to gravitate toward the mitochondria, whereas CPBs with reduced stiffness are present in different intracellular vesicles

Probing solvent-ligand interactions in colloidal nanocrystals by the NMR line broadening

Although solvent-ligand interactions play a major role in nanocrystal synthesis, dispersion formulation, and assembly, there is currently no direct method to study this. Here we examine the broadening of H-1 NMR resonances associated with bound ligands and turn this poorly understood descriptor into a tool to assess solvent-ligand interactions. We show that the line broadening has both a homogeneous and a heterogeneous component. The former is nanocrystal-size dependent, and the latter results from solvent-ligand interactions. Our model is supported by experimental and theoretical evidence that correlates broad NMR lines with poor ligand solvation. This correlation is found across a wide range of solvents, extending from water to hexane, for both hydrophobic and hydrophilic ligand types, and for a multitude of oxide, sulfide, and selenide nanocrystals. Our findings thus put forward NMR line-shape analysis as an indispensable tool to form, investigate, and manipulate nanocolloids