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A reliable knowledge processing framework for combustion science using foundation models

Energy and AI 2024年第2期16卷 396-416页

作者： Vansh Sharma venkat raman Department of Aerospace Engineering University of MichiganAnn Arbor48109-2102MIUSA

This research explores the integration of large language models (LLMs) into scientific data assimilation, focusing on combustion science as a case study. Leveraging foundational models integrated with Retrieval-Augmented Generation (RAG) framework, the study introduces an approach to process diverse combustion research data, spanning experimental studies, simulations, and literature. The multifaceted nature of combustion research emphasizes the critical role of knowledge processing in navigating and extracting valuable information from a vast and diverse pool of sources. The developed approach minimizes computational and economic expenses while optimizing data privacy and accuracy. It incorporates prompt engineering and offline open-source LLMs, offering user autonomy in selecting base models. The study provides a thorough examination of text segmentation strategies, conducts comparative studies between LLMs, and explores various optimized prompts to demonstrate the effectiveness of the framework. By incorporating an external vector database, the framework outperforms a conventional LLM in generating accurate responses and constructing robust arguments. Additionally, the study delves into the investigation of optimized prompt templates for the purpose of efficient extraction of scientific literature. Furthermore, we present a targeted scaling study to quantify the algorithmic performance of the framework as the number of prompt tokens increases. The research addresses concerns related to hallucinations and false research articles by introducing a custom workflow developed with a detection algorithm to filter out inaccuracies. Despite identified areas for improvement, the framework consistently delivers accurate domain-specific responses with minimal human oversight. The prompt-agnostic approach introduced holds promise for future improvements. The study underscores the significance of integrating LLMs and knowledge processing techniques in scientific research, provi

关键词： Large language models(LLM) Foundation models Combustion Knowledge processing Retrieval-augmented generation(RAG)

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A data-driven reduced-order model for stiff chemical kinetics using dynamics-informed training

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Energy and AI 2024年第1期15卷 181-192页

作者： Vijayamanikandan Vijayarangan Harshavardhana A.Uranakara Shivam Barwey Riccardo Malpica Galassi Mohammad Rafi Malik Mauro Valorani venkat raman Hong G.Im CCRC King Abdullah University of Science and TechnologyThuwalSaudi Arabia Argonne Leadership Computing Facility Argonne National LaboratoryLemontIL 60439USA Mechanical and Aerospace Engineering Department Sapienza University of RomeVia Eudossiana18Rome 00184Italy Department of Aerospace Engineering University of MichiganAnn ArborMI 48109USA

A data-based reduced-order model(ROM)is developed to accelerate the time integration of stiff chemically reacting systems by effectively removing the stiffness arising from a wide spectrum of chemical time ***,the objective of this work is to develop a ROM that acts as a non-stiff surrogate model for the time evolution of the thermochemical state vector(temperature and species mass fractions)during an otherwise highly stiff and nonlinear ignition *** model follows an encode-forecast-decode strategy that combines a nonlinear autoencoder(AE)for dimensionality reduction(encode and decode steps)with a neural ordinary differential equation(NODE)for modeling the dynamical system in the AE-provided latent space(forecasting step).By means of detailed timescale analysis by leveraging the dynamical system Jacobians,this work shows how data-based projection operators provided by autoencoders can inherently construct the latent spaces by removing unnecessary fast timescales,even more effectively than physics-based counterparts based on an eigenvalue analysis.A key finding is that the most significant degree of stiffness reduction is achieved through an end-to-end training strategy,where both AE and neural ODE parameters are optimized simultaneously,allowing the discovered latent space to be *** addition to end-to-end training,this work highlights the vital contribution of AE nonlinearity in the stiffness reduction *** the prediction of homogeneous ignition phenomena for H2-air and C2H4-air mixtures,the proposed ROM achieves several ordersof-magnitude increase in the integration time step size when compared to(a)a baseline CVODE solver for the full-chemical system,(b)statistical technique–principal component analysis(PCA),and(c)computational singular perturbation(CSP),a vetted physics-based stiffness-reducing modeling framework.

关键词： Stiff system Chemical kinetics Reacting flows Autoencoders Neural ODE

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A generative adversarial network (GAN) approach to creating synthetic flame images from experimental data

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Energy and AI 2023年第3期13卷 14-24页

作者： Anthony Carreon Shivam Barwey venkat raman University of Michigan Department of AerospaceAnn ArborMIUSA Argonne Leadership Computing Facility Argonne National LaboratoryLemontILUSA

Modern diagnostic tools in turbulent combustion allow for highly-resolved measurements of reacting flows;however,they tend to generate massive data-sets,rendering conventional analysis intractable and *** alleviate this problem,machine learning tools may be used to,for example,discover features from the data for downstream modeling and prediction *** this end,this work applies generative adversarial networks(GANs)to generate realistic flame images based on a time-resolved data set of hydroxide concentration snapshots obtained from planar laser induced fluorescence measurements of a model *** generative model is able to generate flames in attached,lifted,and intermediate configurations dictated by the ***𝑙-means clustering and proper orthogonal decomposition,the synthetic image set produced by the GAN is shown to be visually similar to the real image set,with recirculation zones and burned/unburned regions clearly present,indicating good GAN performance in capturing the experimental data statistical *** with techniques for controlling the configuration of generated flames,this work opens new avenues towards tractable statistical analysis and modeling of flame behavior,as well as rapid and inexpensive flame data generation.

关键词： Generative adversarial network Combustion modeling Data-driven modeling

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Evaluating spatial and elevation-wise daytime/nighttime LST trends across the Indus River Basin

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Journal of Mountain Science 2023年第11期20卷 3154-3172页

作者： Suraj MAL Kavya AGRAWAL Seema RANI Pyarimohan MAHARANA Viswanathan Anantha venkat raman Center for the Study of Regional Development Jawaharlal Nehru UniversityNew Delhi 110067India. Department of Geography Shaheed Bhagat Singh CollegeUniversity of DelhiNew Delhi 110017India Seth Phool Chand Bagla(P.G.)College Hathras(Dr Bhimrao Ambedkar University) Uttar Pradesh 204101India4 Department of GeographyInstitute of ScienceBanaras Hindu UniversityVaranasiUttar Pradesh 221005India Department of Environmental Studies Delhi College of Arts and CommerceUniversity of DelhiNetaji NagarNew Delhi110023India

Land surface temperature(LST)is a crucial parameter for understanding the Earth's surface energy balance,which provides insights into climate dynamics and local environmental ***,the present study aims to evaluate the spatial and elevation-wise trends in the daytime,nighttime,and mean LST across the Indus River Basin(IRB)using MODIS 8-day product for the period between 2002 and *** elevation,cloud cover,and land cover type data are used for explaining the emerging LST *** Theil slope estimator and MannKendall significance test were used for estimating the seasonal and annual LST *** findings show warming in mean daytime(0.020-0.024℃/yr)(except winter and post-monsoon),nighttime(0.013-0.049℃/yr),and mean(0.001-0.042℃/yr)LST in all the seasons(highest in monsoon).The annual mean nighttime LST(0.025℃/yr)is rising significantly faster than the mean daytime LST(0.0016℃/yr),showing the presence of a“nighttime warming effect”,which possibly increases human discomfort,particularly during the warm pre-monsoon and humid monsoon ***-dependent warming(EDW)is predominant in mean daytime LST in two elevation zones,namely(i)0-3 km and(ii)above 4 km,in all seasons,except in *** contrast,EDW in mean nighttime LST is observed up to 3 km and above 6 km in the basin in all the seasons,excluding *** warming trend in LST may be attributed to rising atmospheric moisture,cloud cover,declining snow cover,and changes in land cover to non-vegetated ***,further investigations will involve exploring the underlying factors contributing to the observed anomalies in nighttime LST,considering variables such as regional energy balance and atmospheric *** research contributes to an understanding of the thermal dynamics in the mountain basin,aiding in climate studies,land management,and the development of effective adaptation strategies in the IRB.

关键词： Land surface temperature Elevation dependent warming Indus river basin South Asia

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Comparison of outcomes between 2 week versus 4 week stenting in pediatric pyeloplastyd——A single centre observational study

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Asian Journal of Urology 2020年第4期7卷 327-331页

作者： Santosh Dey venkat Shankar raman Tarun Peela Karunesh Chand Naveen Chandra Department of Pediatric Surgery Army HospitalPuneIndia

Objective:To compare the surgical outcomes,improvement in renal function and complications between early stent removal(2 weeks)and late stent removal(4 weeks)after pediatric open ***:A total of 72 open pyeloplasty were included in the ***-three underwent late stent removal(Group 1)and 29 underwent early stent removal(Group 2).Pre-operative and post-operative follow-up data were compared to see the effect of early stent removal on the postoperative drainage pattern at 6 months after surgery and improvement in split function of affected *** complications between the two groups were also ***:Both the groups were matched with respect to age,sex,side and antero-posterior diameter of ***-operative mean split function in Group 1 was 42%(26%e54%)while it was 39%(19%e42%)in Group 2(pZ0.37).Postoperative improvement in drainage pattern was seen in 69 out of 72(96%)patients,41 out of 43(95%)in Group 1 and 28 out of 29(97%)in Group *** in split function occurred in 35 of 38(97%)in Group 1 and 23 of 26(88%)patients in Group 2(pZ0.51).Complications were seen in nine out of 72(12.5%)*** of complication in Group 1 was 16%(7/43)and Group 2 was 7%(2/29),and relative risk was ***:A shorter duration of double J stenting is as effective as a longer stenting period in terms of surgical success outcomes and improvement in split renal function along with a decreased risk of stent related complications.

关键词： Pelvi-ureteric junction obstruction Anderson-Hynes pyeloplasty Double J stenting Outcomes

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Socialist Market Economy and the Challenge of ＇Social Management＇ in China

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Fudan Journal of the Humanities and Social Sciences 2014年第1期7卷 119-123页

作者： G. venkat raman Humanities and Liberal Arts in Management Indian Institute of Management KozhikodeKozhikode 673570 Kerala India

Paolo Urio is Professor Emeritus in the University of Geneva, Switzerland and teaches Public Administration and Management. In this book Urio has presented his findings and understanding of China on the basis of his very active involvement in the management of the second phase of the ＂Sino-Swiss Management Training Programme in the Public Sector of China.＂ He mentions in his book that the project lasted 6 years （1997-2003） and it was during these years that he got an opportunity to come into close contact with Chinese scholars, administrators, party cadres along with providing him an opportunity to travel the mainland extensively.

关键词：社会管理中国学者社会主义市场经济公共行政公共部门调查结果管理人员党员干部

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A set of SCAR markers in cluster bean (<i>Cyamopsis tetragonoloba</i>L. Taub) genotypes

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Advances in Bioscience and Biotechnology 2014年第2期5卷 131-141页

作者： Pratibha Sharma Vinod Kumar K. venkat raman Kapil Tiwari Department of Bioscience & Biotechnology Banasthali University Rajasthan India National Research Center on Plant Biotechnology IARI New Delhi India

Cluster bean, one of the most important cash legume crop has played an increasingly important role in wide range of industries. Owing to the significance of molecular marker studies in numerous applications including in genetic improvement of crops, there is an obvious need to undertake such studies in cluster bean. In the present work, 35 genotypes of cluster bean were collected from different states of India and analyzed using RAPD and ISSR markers. Further SCAR marker system was introduced in order to increase the reproducibility of the polymorphism and specificity. For this polymorphic (RP-3, 1000 bp;RP-19, 1250 bp and 1100 bp) and geographical specific bands (RP-9, 650 bp) from RAPD as well as genotype specific band (IS-8, 550 bp) from genotype RGC-1031 (Rajasthan) from ISSR were selected and converted into SCAR markers. The study revealed first set of sequence-based SCAR markers in cluster bean which found more specific information using RAPD and ISSR profiles. One genotype specific SCAR-20 for RGC-1031 (tolerant genotype against Macrophomina phaseolina), could be used to prove identity of the genotype for improvement as well for its genetic purity assessment. Another SCAR-8 was selected due to its specificity for cluster bean genotypes from Rajasthan which might be important for population admixture studies.

关键词： Cluster Bean ISSR RAPD SCAR

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Tuning Optical Properties of Graphene Oxide under Compressive Strain Using Wet Ball Milling Method

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Graphene 2016年第2期5卷 73-80页

作者： M. venkat Narayana S. Narayana Jammalamadaka Magnetic Materials and Device Physics Laboratory Department of Physics Indian Institute of Technology Hyderabad Hyderabad-502285 India

We report on the effect of compressive stress on the optical properties of graphene oxide using a wet ball milling technique. For this purpose, graphene oxide was prepared using the modified Hummer’s method and subsequently processed with wet ball milling. X-ray diffraction infers a peak at 9.655° which is the allowed reflection for the graphene oxide. The Williamson-Hall method is used to quantify the strain on the 10 hrs and 20 hrs ball milled graphene oxide samples and is found to be 4.2% and 4.8% respectively. Although we applied strain on the graphene oxide, it actually helped to reduce the defects which are confirmed by the intensity drop-off of D-peak in raman spectroscopy. Indeed there exists a band gap alteration of 0.14 eV for an applied compressive strain of ~4.8%, hinting that the reduction in oxygen functional groups and the same is confirmed with the Fourier Transform Infrared Spectroscopy (FTIR). The present results would be helpful in developing graphene oxide based flexible memories and optoelectronic devices.

关键词： Graphene Oxide Band Gap Oxygen Functional Groups Optical Properties

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