168,008 research outputs found
Recent Results From the EU POF-PLUS Project: Multi-Gigabit Transmission Over 1 mm Core Diameter Plastic Optical Fibers
Full text linkRecent activity to achieve multi-gigabit transmission over 1 mm core diameter graded-index and step-index plastic optical fibers for distances up to 50 meters is reported in this paper. By employing a simple intensity-modulated direct-detection system with pulse amplitude or digital multi-tone modulation techniques, low-cost transceivers and easy to install large-core POFs, it is demonstrated that multi-gigabit transmission up to 10 Gbit/s over 1-mm core diameter POF infrastructure is feasible. The results presented in this paper were obtained in the EU FP7 POF-PLUS project, which focused on applications in different scenarios, such as in next-generation in-building residential networks and in datacom applications
Employing M1 direct calibration/de-embedding approaches for large signal model validation at mm-wave frequencies
No full textIn this contribution, we employ direct calibration/de-embedding approaches to validate the large signal device model of state-of-the-art HBTs and CMOS technologies operating in the mm-wave frequency band WR6. The capability of placing the first tier calibration reference plane in close proximity to the DUT allows the large signal metric to be directly compared with foundry models.Green 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.Electronic
Development and specifics of the construction of a LKMK 8000 large crank press
No full textThe article deals with the development of large forging presses for die forging. It analyses individual aspects of the development of large presses. This is followed by market analysis and a search of design solutions by individual manufacturers. Set of design recommendations has been compiled from a variety of technical solutions, according to which a press that surpasses the competition can be properly assembled
MM-Forecast: A Multimodal Approach to Temporal Event Forecasting with Large Language Models
Full text linkWe study an emerging and intriguing problem of multimodal temporal event forecasting with large language models. Compared to using text or graph modalities, the investigation of utilizing images for temporal event forecasting has not been fully explored, especially in the era of large language models (LLMs). To bridge this gap, we are particularly interested in two key questions of: 1) why images will help in temporal event forecasting, and 2) how to integrate images into the LLM-based forecasting framework. To answer these research questions, we propose to identify two essential functions that images play in the scenario of temporal event forecasting, i.e., highlighting and complementary. Then, we develop a novel framework, named MM-Forecast. It employs an Image Function Identification module to recognize these functions as verbal descriptions using multimodal large language models (MLLMs), and subsequently incorporates these function descriptions into LLM-based forecasting models. To evaluate our approach, we construct a new multimodal dataset, MidEast-TE-mm, by extending an existing event dataset MidEast-TE-mini with images. Empirical studies demonstrate that our MM-Forecast can correctly identify the image functions, and further more, incorporating these verbal function descriptions significantly improves the forecasting performance. The dataset, code, and prompts are available at https://github.com/LuminosityX/MM-Forecast
Large-scale QM/MM free energy simulations of enzyme catalysis reveal the influence of charge transfer
No full textHybrid quantum mechanical-molecular mechanical (QM/MM) simulations provide key insights into enzyme structure–function relationships. Numerous studies have demonstrated that large QM regions are needed to systematically converge ground state, zero temperature properties with electrostatic embedding QM/MM. However, it is not well known if ab initio QM/MM free energy simulations have this same dependence, in part due to the hundreds of thousands of energy evaluations required for free energy estimations that in turn limit QM region size. Here, we leverage recent advances in electronic structure efficiency and accuracy to carry out range-separated hybrid density functional theory free energy simulations in a representative methyltransferase. By studying 200 ps of ab initio QM/MM dynamics for each of five QM regions from minimal (64 atoms) to one-sixth of the protein (544 atoms), we identify critical differences between large and small QM region QM/MM in charge transfer between substrates and active site residues as well as in geometric structure and dynamics that coincide with differences in predicted free energy barriers. Distinct geometric and electronic structure features in the largest QM region indicate that important aspects of enzymatic rate enhancement in methyltransferases are identified with large-scale electronic structure.<br
Protein-ligand binding affinities from large-scale quantum mechanical simulations
No full textThe accurate prediction of protein-drug binding affinities is a major aim of computational drug optimisation and development. A quantitative measure of binding affinity is provided by the free energy of binding, and such calculations typically require extensive configurational sampling of entities such as proteins with thousands of atoms. Current binding free energy methods use force fields to perform the configurational sampling and to compute interaction energies. Due to the empirical nature of force fields and the neglect of electrons, electron polarisation and charge transfer are not accounted for explicitly. This can limit the accuracy with which interactions are calculated and consequently the free energies obtained. Ideally ab initio quantum chemistry approaches should be used as these explicitly include the electrons. However, conventional ab initio approaches are not suitable due to their prohibitively high computational cost and unfavourable scaling.In this thesis we use large-scale ab initio quantum chemistry calculations within the Density Functional Theory (DFT) method to address the above mentioned limitations of force fields. To obtain quantitative results with ab initio approaches it is important to converge the calculations with the size of the basis set. For this reason we have used the ONETEP program, which is capable of linear-scaling DFT with near-complete basis set accuracy.A well known binding free energy approach is the Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA), which obtains free energies from evaluation of the energy of configurations in an implicit solvent model. We present the first application of a “QM-PBSA” approach to a protein-ligand system containing over 2600 atoms. In this QM-PBSA approach the energies of the configurations in vacuum are evaluated with ONETEP. The solvation energies were also obtained with ONETEP using a minimal parameter implicit solvent model within the self-consistent calculation. Large-scale DFT calculations were also applied within a more theoretically rigorous free energy approach which can, in principle, obtain the full entropic contributions to free energy change. The method performs a mutation from a molecular mechanical (MM) description to an quantum mechanical (QM) description of a system. As a result a QM correction is added to the relative binding free energy obtained from a thermodynamic integration calculation within the MM description.This approach was combined with an electrostatic embedding model within ONETEP and used to calculate the hydration energies of small molecules. As well as the computation of more accurate energies, large-scale DFT calculation compute the electron density of the entire system. Using electron density analysis approaches, such as the Hirshfeld density analysis, in combination with energy decomposition approaches, such as a second order perturbation estimate of natural bond orbital interactions, both qualitative and quantitative understandings can be gained into the contributions of particular chemical functional groups that define protein-ligand interactions. These two approaches where applied to study complexes of the Phosphodiesterase type 5 protein and used to rank ligand binding affinities that agree well with then experimentally observed trends
Icing wind tunnel measurements of supercooled large droplets using the 12 mm total water content cone of the Nevzorov probe
Full text linkSupercooled large droplet (SLD) icing can occur behind the protected surfaces of an aircraft and create severe aerodynamic disturbances, which represent a safety hazard for aviation. Liquid water content (LWC) measurements in icing conditions that contain SLDs require instruments that are able to sample unimodal and bimodal droplet size distributions with droplet diameters from 2 to 2000 µm. No standardized detection method exists for this task. A candidate instrument, which is currently used in icing wind tunnel (IWT) research, is the Nevzorov probe. In addition to the standard 8 mm total water content (TWC) collector cone, a novel instrument version also features a 12 mm diameter cone, which might be advantageous for collecting the large droplets characteristic of SLD conditions. In the scope of the two EU projects, SENSors and certifiable hybrid architectures for safer aviation in ICing Environment (SENS4ICE) and ICE GENESIS, we performed measurement campaigns in SLD icing conditions in IWTs in Germany, Austria and the USA. We obtained a comprehensive data set of measurements from the LWC sensor, the 8 mm cone sensor and the 12 mm cone sensor of the Nevzorov probe, and from the tunnel reference instrumentation. In combination with measurements of the particle size distribution, we experimentally derive a collision efficiency curve that is based on a suitable functional form for the new 12 mm cone for median volume diameters (MVDs) between 12 and 58 µm and wind tunnel speeds from 40 to 85 m s−1. Knowledge of this curve allows us to correct the LWC measurements of the 12 mm cone (LWC12) in particular for the inevitably high decrease in collision efficiency for small droplet diameters. In unimodal SLD conditions, with MVDs between 128 and 720 µm, LWC12 generally agrees within ±20 % with the tunnel LWC reference values from a WCM-2000 and an isokinetic probe. An increase in the difference between LWC12 and the WCM-2000 measurements at larger MVDs indicates better droplet collection properties of the 12 mm cone. Similarly, the favorable detector dimensions of the 12 mm cone explain a 7 % enhanced detection efficiency compared to the 8 mm cone; however this difference falls within the instrumental uncertainties. Data collected in various bimodal SLD conditions with MVDs between 16 and 534 µm and LWCs between 0.22 and 0.72 g m−3 also show an agreement within ±20 % between LWC12 and the tunnel LWC, which demonstrates the suitability of the Nevzorov sensor head with the 12 mm cone for measurements of LWC in Appendix O icing conditions.Aircraft Noise and Climate Effect
Outcomes of Conventional 8.0-mm Versus Large 9.0-mm Diameter Deep Anterior Lamellar Keratoplasty for Keratoconus
No full textPurpose:The purpose of the study was to compare the clinical outcomes of large 9.0-mm diameter and conventional 8.0-mm big-bubble deep anterior lamellar keratoplasty (DALK).Methods:In this comparative, retrospective interventional case series, medical records of 124 cases of large 9.0-mm diameter DALK from January 2017 to December 2019 and 133 conventional 8.0-mm DALK from January 2014 to December 2016 performed by a single surgeon for the indication of keratoconus were reviewed. Main outcome measures were best spectacle-corrected visual acuity (BSCVA), refractive astigmatism (RA), and postoperative complication rates.Results:Postoperative logarithm of the minimum angle of resolution BSCVA did not significantly differ between 9.0-mm and 8.0-mm DALK at any time points. Although the cumulative percentage of eyes achieving Snellen BSCVA of 20/40 or better was comparable between groups (9.0-mm DALK: 93%, 8.0-mm DALK: 90%, P = 0.571), the cumulative percentage of eyes achieving 20/20 or better (9.0-mm DALK: 44%, 8.0-mm DALK: 26%, P = 0.01) and 20/25 or better (9.0-mm DALK: 74%, 8.0-mm DALK: 59%, P = 0.03) was significantly higher in the 9.0-mm DALK group. RA was significantly lower in the 9.0-mm DALK group compared with the 8.0-mm DALK group during all time points (P < 0.001). The percentage of eyes with RA less than or equal to 4.0 D was significantly lower in the 9.0-mm DALK patients (90%) compared with in 8.0-mm DALK group (72%) (P = 0.002). Postoperative complication rates were similar between groups.Conclusions:Compared with conventional 8.0-mm DALK, large 9.0-mm DALK can provide superior visual outcomes at higher levels of Snellen BSCVA and significantly lower degrees of astigmatism without an increased risk of immune rejection and graft failure
Auxiliary device for accurate measurement by the smartvision system
No full textThe article deals with the design of equipment for accurate measurement or checking linear dimensions using a smart vision system. Commercial smart vision systems can not accurately measure large linear dimensions because the precision of the camera sensor decreases with distance from measured object. The main benefit of the proposed solution is the possibility of continuous measuring in production lines with high precision even for very long dimensions. © 2018, MM publishing Ltd. All rights reserved.APVV-15-0602, APVV, Agentúra na Podporu Výskumu a Vývoja; NPU I LO1303, MŠMT, Ministerstvo Školství, Mládeže a TělovýchovyAgency for Research and Development [APVV-15-0602and, NPU I LO1303]; Ministry of Education, Youth and Sports of the Czech RepublicMinistry of Education, Youth & Sports - Czech Republi
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