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Articles 29971 - 30000 of 291657

Full-Text Articles in Physical Sciences and Mathematics

Fluorescent Ph Indicators For Classroom Demonstration Of Buffer Action, Mark Muyskens, Mariana Dykstra, Yejin Chung Jan 2024

Fluorescent Ph Indicators For Classroom Demonstration Of Buffer Action, Mark Muyskens, Mariana Dykstra, Yejin Chung

University Faculty Publications and Creative Works

We report an attractive update to the demonstration of acid−base buffer action that is appropriate for ease of use and getting attention in the classroom. The twist is based on new fluorophore information and the recent availability of UV flashlights serving as an ideal, portable excitation light source. The pH-dependent fluorescence comes from a choice among three natural sources, namely narra tree wood extract, kidneywood extract, and scopoletin, which is a purchasable coumarin, that all perform equally well. We provide practical details for performing the buffer demonstration at scales of 100 and 1000 mL and give background information for context


Easy, Bright, Fluorescence Demonstration Of Buffer Action, Mariana Dykstra, Yejin Chung, Mark Muyskens Jan 2024

Easy, Bright, Fluorescence Demonstration Of Buffer Action, Mariana Dykstra, Yejin Chung, Mark Muyskens

University Faculty Publications and Creative Works

We report an attractive update to the demonstration of acid–base buffer action that is appropriate for ease of use and getting attention in the classroom. The twist is based on new fluorophore information and the recent availability of UV flashlights serving as an ideal, portable excitation light source. The pH-dependent fluorescence comes from a choice among three natural sources, namely narra tree wood extract, kidneywood extract, and scopoletin, which is a purchasable coumarin, that all perform equally well. We provide practical details for performing the buffer demonstration at scales of 100 and 1000 mL and give background information for context.


Using Deep Learning Techniques To Find The 4d Slice Genus Of A Knot, Dylan Skinner Jan 2024

Using Deep Learning Techniques To Find The 4d Slice Genus Of A Knot, Dylan Skinner

Undergraduate Honors Theses

Deep reinforcement learning (DRL) has proven to be exceptionally effective in addressing challenges related to pattern recognition and problem-solving, particularly in domains where human intuition faces limitations. Within the field of knot theory, a significant obstacle lies in the construction of minimal-genus slice surfaces for knots of varying complexity. This thesis presents a new approach harnessing the capabilities of DRL to address this challenging problem. By employing braid representations of knots, our methodology involves training reinforcement learning agents to generate minimal-genus slice surfaces. The agents achieve this by identifying optimal sequences of braid transformations with respect to a defined objective …


Phase-Slip Centers As Cooling Engines, Iris Mowgood, Serafim Teknowijoyo, Sara Chahid, Armen Gulian Jan 2024

Phase-Slip Centers As Cooling Engines, Iris Mowgood, Serafim Teknowijoyo, Sara Chahid, Armen Gulian

Mathematics, Physics, and Computer Science Faculty Articles and Research

Based on time-dependent Ginzburg-Landau system of equations, Éliashberg’s kinetic equations and finite element modeling, we analyze phonon emission by the phase-slip centers in superconducting filaments. Our results show that in the dissipative regime with these centers, thin superconducting filaments can be effective in originating not only positive but also negative thermal fluxes, i.e., they both generate and absorb phonons. In a stationary oscillatory regime, at a given moment of time, this generation and absorption of phonons reveals itself as positive and negative spectrum of phonons at different spectral ranges. Moreover, at a given spectral range, the emission reverses its sign …


Superconductivity Of Amorphous And Crystalline Re–Lu Films, Serafim Teknowijoyo, Armen Gulian Jan 2024

Superconductivity Of Amorphous And Crystalline Re–Lu Films, Serafim Teknowijoyo, Armen Gulian

Mathematics, Physics, and Computer Science Faculty Articles and Research

We report on superconducting properties of a novel material: rhenium-lutetium films. Different compositions of RexLu binary are explored from x ≈ 3.8 to close to pure Re stoichiometry. The highest critical temperature, up to 7 K, is obtained for x ≈ 10.5 in accordance with electron dispersive spectroscopy results. Depending on the deposition conditions, polycrystalline or amorphous films are obtainable, both of which are interesting for practical use. Crystalline structure of polycrystalline phase is identified as a non-centrosymmetric superconductor using grazing incidence x-ray diffractometry. Superconducting properties were characterized both resistively and magnetically. Magnetoresistivity and AC/DC susceptibility measurements allowed …


Some Remarks On Possible Superconductivity Of Composition Pb9Cup6O25, Pablo Abramian-Barco, A. Kuzanyan, Vahan Nikoghosyan, Serafim Teknowijoyo, Armen Gulian Jan 2024

Some Remarks On Possible Superconductivity Of Composition Pb9Cup6O25, Pablo Abramian-Barco, A. Kuzanyan, Vahan Nikoghosyan, Serafim Teknowijoyo, Armen Gulian

Mathematics, Physics, and Computer Science Faculty Articles and Research

A material called LK-99, a modified-lead apatite crystal structure with the composition Pb10xCux(PO4)6O (0.9 < x < 1.1) has been reported to be an above-room-temperature superconductor at ambient pressure. It is hard to expect that it will be straightforward for other groups to reproduce the original results. We provide here some remarks which may be helpful for a success.


Water Whiplash In Mediterranean Regions Of The World, Citlalli Madrigal, Rama Bedri, Thomas Piechota, Wenzhao Li, Glenn Tootle, Hesham El-Askary Jan 2024

Water Whiplash In Mediterranean Regions Of The World, Citlalli Madrigal, Rama Bedri, Thomas Piechota, Wenzhao Li, Glenn Tootle, Hesham El-Askary

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The presence of weather and water whiplash in Mediterranean regions of the world is analyzed using historical streamflow records from 1926 to 2023, depending on the region. Streamflow from the United States (California), Italy, Australia, Chile, and South Africa is analyzed using publicly available databases. Water whiplash—or the rapid shift of wet and dry periods—are compared. Wet and dry periods are defined based on annual deviations from the historical record average, and whiplash occurs when there is an abrupt change that overcomes an accommodated deficit or surplus. Of all the stations, there are more dry years (56%) than wet years …


On Modeling Arterial Blood Flow With Or Without Solute Transport And In Presence Of Atherosclerosis, Daniel N. Riahi, Saulo Orizaga Jan 2024

On Modeling Arterial Blood Flow With Or Without Solute Transport And In Presence Of Atherosclerosis, Daniel N. Riahi, Saulo Orizaga

School of Mathematical & Statistical Sciences Faculty Publications

In this article, we review previous studies of modeling problems for blood flow with or without transport of a solute in a section of arterial blood flow and in the presence of atherosclerosis. Moreover, we review problems of bio-fluid dynamics within the field of biophysics. In most modeling cases, the presence of red blood cells in the plasma is taken into account either by using a two-phase flow approach, where blood plasma is considered as one phase and red blood cells are counted as another phase, or by using a variable viscosity formula that accounts for the amount of hematocrit …


Digitizing Delphi: Educating Audiences Through Virtual Reconstruction, Kate Koury Jan 2024

Digitizing Delphi: Educating Audiences Through Virtual Reconstruction, Kate Koury

The Journal of Purdue Undergraduate Research

Implementing a 3D model into a virtual space allows the general public to engage critically with archaeological processes. There are many unseen decisions that go into reconstructing an ancient temple. Analysis of available materials and techniques, predictions of how objects were used, decisions of what sources to reference, puzzle piecing broken remains together, and even educated guesses used to fill gaps in information often go unobserved by the public. This work will educate users about those choices by allowing the side-by-side comparison of conflicting theories on the reconstruction of the Tholos at Delphi, which is an ideal site because of …


Promises And Risks Of Applying Ai Medical Imaging To Early Detection Of Cancers, And Regulation For Ai Medical Imaging, Yiyao Zhang Jan 2024

Promises And Risks Of Applying Ai Medical Imaging To Early Detection Of Cancers, And Regulation For Ai Medical Imaging, Yiyao Zhang

The Journal of Purdue Undergraduate Research

No abstract provided.


The Impact Of Accessible Data On Cyberstalking, Elise Kwan Jan 2024

The Impact Of Accessible Data On Cyberstalking, Elise Kwan

The Journal of Purdue Undergraduate Research

No abstract provided.


Model Selection Through Cross-Validation For Supervised Learning Tasks With Manifold Data, Derek Brown Jan 2024

Model Selection Through Cross-Validation For Supervised Learning Tasks With Manifold Data, Derek Brown

The Journal of Purdue Undergraduate Research

No abstract provided.


The Effects Of Wildfire Aerosol Emissions On Air Quality, Emma Braun, Audrey Shirley Jan 2024

The Effects Of Wildfire Aerosol Emissions On Air Quality, Emma Braun, Audrey Shirley

The Journal of Purdue Undergraduate Research

No abstract provided.


Upleft: Pick Up Leftovers, Uplift Those In Need, Veronica Galles Jan 2024

Upleft: Pick Up Leftovers, Uplift Those In Need, Veronica Galles

The Journal of Purdue Undergraduate Research

No abstract provided.


Characterizing Differential Reflectivity Calibration Dependence On Environmental Temperature Using The X-Band Teaching And Research Radar (Xtrra): Looking For A Relationship Between Temperature And Differential Reflectivity Bias, Emma Miller Jan 2024

Characterizing Differential Reflectivity Calibration Dependence On Environmental Temperature Using The X-Band Teaching And Research Radar (Xtrra): Looking For A Relationship Between Temperature And Differential Reflectivity Bias, Emma Miller

The Journal of Purdue Undergraduate Research

Calibration scans are important for the maintenance of data and the quality of the information that radars output. In this study we looked for a temperature dependency in a full year’s worth of differential reflectivity (ZDR) calibration scan data collected by the X-band Teaching and Research Radar (XTRRA) located near the Purdue University campus. In a vertically pointing calibration scan, the radar scans the drops from below while rotating. From this angle, the overall shape will be circular, which corresponds to a ZDR value of approximately 0 dB. To process the data for the year 2021, a Python script was …


Machine Learning Of Big Data: A Gaussian Regression Model To Predict The Spatiotemporal Distribution Of Ground Ozone, Jerry Gu Jan 2024

Machine Learning Of Big Data: A Gaussian Regression Model To Predict The Spatiotemporal Distribution Of Ground Ozone, Jerry Gu

The Journal of Purdue Undergraduate Research

Tracking pollution levels on the ground is important to the environment and public health. One of the pollutants of concern is ozone, which, at high concentrations, can cause respiratory and cardiovascular problems. The National Center for Atmospheric Research (NCAR) has published valuable ozone data obtained from ground-based sensors installed at selected locations. Because it is unfeasible to measure the exact ozone levels everywhere at any time, it would be valuable to predict the temporal-spatial distributions of ozone concentration based on existing data. This would help us better understand the patterns and trends in the data and make better decisions to …


A Computational Profile Of Invasive Lionfish In Belize: A New Insight On A Destructive Species, Joshua E. Balan Jan 2024

A Computational Profile Of Invasive Lionfish In Belize: A New Insight On A Destructive Species, Joshua E. Balan

The Journal of Purdue Undergraduate Research

Since their discovery in the region in 2009, invasive Indonesian-native lionfish have been taking over the Belize Barrier Reef. As a result, populations of local species have dwindled as they are either eaten or outcompeted by the invaders. This has led to devastating losses ecologically and economically; massive industries in the local nations, such as fisheries and tourism, have suffered greatly. Attempting to combat this, local organizations, from nonprofits to ecotourism companies, have been manually spear-hunting them on scuba dives to cull the population. One such company, Reef Conservation Institute (ReefCI), operating out of Tom Owens Caye outside of Placencia, …


Clouds In The Ancient Lunar Atmosphere: Water Ice Nucleation On Aerosol Simulants, Mariana C. Aguilar Jan 2024

Clouds In The Ancient Lunar Atmosphere: Water Ice Nucleation On Aerosol Simulants, Mariana C. Aguilar

The Journal of Purdue Undergraduate Research

Today’s moon is vastly different from what it was 3 billion years ago. At that time, it was home to a collisional atmosphere formed through massive amounts of volcanism, releasing enough subsurface gas to sustain surface pressures of up to 1 kPa. Observations of our solar system have taught us that all dense atmospheres are host to clouds and aerosols, and we expect the Moon’s to be no different. Knowing when, where, and under what conditions cloud particles form is important for understanding the evolution of the lunar atmosphere, how it reacted to temperature gradients, and how it cycled volatiles. …


The Aim To Decentralize Economic Systems With Blockchains And Crypto, Mary Lacity Jan 2024

The Aim To Decentralize Economic Systems With Blockchains And Crypto, Mary Lacity

Arkansas Law Review

As an information systems (“IS”) professor, I wrote this Article for legal professionals new to blockchains and crypto. This target audience likely is most interested in crypto for its legal implications—depending on whether it functions as currencies, securities, commodities, or properties; however, legal professionals also need to understand crypto’s origin, how transactions work, and how they are governed.


Acknowledgement Of Reviewers Jan 2024

Acknowledgement Of Reviewers

Journal of Sustainable Mining

No abstract provided.


A Survey On Training Challenges In Generative Adversarial Networks For Biomedical Image Analysis, Muhammad Muneeb Saad, Ruairi O'Reilly, Mubashir Husain Rehmani Jan 2024

A Survey On Training Challenges In Generative Adversarial Networks For Biomedical Image Analysis, Muhammad Muneeb Saad, Ruairi O'Reilly, Mubashir Husain Rehmani

Department of Computer Science Publications

In biomedical image analysis, the applicability of deep learning methods is directly impacted by the quantity of image data available. This is due to deep learning models requiring large image datasets to provide high-level performance. Generative Adversarial Networks (GANs) have been widely utilized to address data limitations through the generation of synthetic biomedical images. GANs consist of two models. The generator, a model that learns how to produce synthetic images based on the feedback it receives. The discriminator, a model that classifies an image as synthetic or real and provides feedback to the generator. Throughout the training process, a GAN …


Dinsar Analysis And Geophysical Modeling Of 2022 November 23 Gölyaka-Düzce Earthquake, Şükrü Onur Karaca, Gülteki̇n Erten, Batuğhan Yikmaz, Seli̇m Özalp Jan 2024

Dinsar Analysis And Geophysical Modeling Of 2022 November 23 Gölyaka-Düzce Earthquake, Şükrü Onur Karaca, Gülteki̇n Erten, Batuğhan Yikmaz, Seli̇m Özalp

Turkish Journal of Earth Sciences

Numerous significant earthquakes have occurred along the North Anatolian Fault Zone (NAFZ), Türkiye’s most important fault zone. An earthquake with magnitude of Mw 6.0 occurred near the Gölyaka District of Düzce Province at 04:08 local time on November 23, 2022. According to the moment tensor solutions published by national and international seismology centers, the earthquake occurred at the northeast end of the Karadere segment within the NAFZ and was caused by a right-lateral strike-slip fault in the NW-SE direction. In this study, the differential interferometric synthetic aperture radar (InSAR) method was employed to analyze the deformation. Four Sentinel-1A complex datasets …


Evaluating The Neotectonic Activities Of The Eastern Makran At The Northern Edge Of The Triple Junction In Southwest Pakistan, Waseem Khan, Ke Zhang, Hao Liang Jan 2024

Evaluating The Neotectonic Activities Of The Eastern Makran At The Northern Edge Of The Triple Junction In Southwest Pakistan, Waseem Khan, Ke Zhang, Hao Liang

Turkish Journal of Earth Sciences

A number of five GIS-based indices, such as stream slope (Ss), surface roughness (Sr), asymmetric factor (Af), hypsometry integral (Hi), and stream-length gradient (SL), were summarised to examine the intensity of the index of tectonic activity (IAT) in 43 subbasins of Hingol Basin at the northern edge of the triple junction in southwest Pakistan. In addition, tectonic influences were identified by knickpoints spatial distribution and field surveys. The majority of the indices are consistent and display roughly the same classifications. The uncertain results have a less substantial impact on the obtained results in most of the 43 subbasins. Using these …


Microfacies, Geometry And Growth Phases Of Microbial Mound In Gucheng Area, Southeastern Tarim Basin, China, Xu Chen, Iftikhar Satti, Yuwen Dong Jan 2024

Microfacies, Geometry And Growth Phases Of Microbial Mound In Gucheng Area, Southeastern Tarim Basin, China, Xu Chen, Iftikhar Satti, Yuwen Dong

Turkish Journal of Earth Sciences

Microbial mound is favorable carbonate reservoir for petroleum exploration, especially for the deep tight reservoirs in the Tarim petroliferous basin. Due to lack of effective research methods, it is difficult to analyze its unique sedimentary structure and evolution process. In this study, based on cores, thin-sections, logging, 3D seismic data and geochemical test data, the petrographic texture, microfacies, geometry and growth phases of microbial mound in Gucheng area, Southeastern Tarim Basin were investigated, which can be used to reconstruct dynamic evolution of the microbial mounds and discuss the controlling factors. The major results are as follows: (1) Gucheng area is …


Genesis Of Efficient Reservoirs In Mixed Sedimentary Setting: A Case Study Of Benxi Formation In The Gaoqiao Area, Ordos Basin, Shu Liu, Jinbu Li, Fengbo Jin, Haifeng Liu, Meng Wang, Yulin Cheng, Yulin Cheng, Xiaohong Zhong, Hao Lu Jan 2024

Genesis Of Efficient Reservoirs In Mixed Sedimentary Setting: A Case Study Of Benxi Formation In The Gaoqiao Area, Ordos Basin, Shu Liu, Jinbu Li, Fengbo Jin, Haifeng Liu, Meng Wang, Yulin Cheng, Yulin Cheng, Xiaohong Zhong, Hao Lu

Turkish Journal of Earth Sciences

The Benxi-Taiyuan Formation in the southern region of the Ordos Basin represents a typical mixed sedimentary system, which has witnessed recent breakthroughs in the exploration of tight sandstone gas within the Benxi Formation. However, the development patterns of reservoirs in this mixed sedimentary area remain unclear, influenced by the sedimentary model and the distribution scale of sedimentary sandstone bodies. This study investigates the paleogeomorphology, sedimentary model, sandstone body type, petrological characteristics, and pore structure of the Benxi Formation. Field profiles, drilling core observations, microscopic section analysis, scanning electron microscopy (SEM), high-pressure mercury injection (HPMI), and physical property analysis are employed. …


Mineralogical And Geochemical Characteristics Of The Upper Cretaceous And Lower Paleocene Parts Of The Germav Formation: Southeastern Türkiye, Sema Teti̇ker Jan 2024

Mineralogical And Geochemical Characteristics Of The Upper Cretaceous And Lower Paleocene Parts Of The Germav Formation: Southeastern Türkiye, Sema Teti̇ker

Turkish Journal of Earth Sciences

The mineralogical and chemical characteristics of Upper Cretaceous-Lower Paleocene claystone sediment samples taken from Mardin and Batman, located in southeastern Türkiye, were analyzed in the present study. The clay mineral paragenesis in the Upper Cretaceous units consisted of chlorite-smectite (C-S) and illite, whereas the Lower Paleocene unit consisted of chlorite-vermiculite (CV) and vermiculite minerals. Analyses conducted on clay samples indicated high levels of Al, Mg, Fe, Cr, V, Ni, and Zr. Low levels of alkali and alkaline earth elements (Mg, Na, Ca, K) in the clay-rich sediments suggest relatively high-grade weathering in the source area. The mineralogical compositions, major elemental …


Landslide Susceptibility Assessment Of The Asi Watershed, Southern Türkiye, Senem Teki̇n, Adolfo Quesada Román, Tolga Çan Jan 2024

Landslide Susceptibility Assessment Of The Asi Watershed, Southern Türkiye, Senem Teki̇n, Adolfo Quesada Román, Tolga Çan

Turkish Journal of Earth Sciences

Landslides constitute recurrent natural hazards worldwide with greater socioeconomic impacts in low-income places. Landslide susceptibility studies are carried out to determine the potential for landslides to occur in a region, to predict possible risks in the future and to integrate this information into sustainable planning and management strategies. Slip-type landslides occur in limited areas of less than 1% of the Asi watershed in Southern Türkiye. Therefore, meaningful estimations cannot be made with classical statistical models. So, using the maximum entropy approach (MaxEnt), a technique for estimating based on a small number of observations, a landslide susceptibility assessment was constructed. The …


An Experimental Investigation On The Discrete Poisson’S Upward Continuation Of Anomalous Gravity Field Data, Mehmet Si̇mav, Bi̇hter Erol, Muhammet Aki̇f Gülender, Serdar Erol Jan 2024

An Experimental Investigation On The Discrete Poisson’S Upward Continuation Of Anomalous Gravity Field Data, Mehmet Si̇mav, Bi̇hter Erol, Muhammet Aki̇f Gülender, Serdar Erol

Turkish Journal of Earth Sciences

The Poisson upward continuation of gravity field functionals, typically given on the Earth’s irregular topography with limited spatial extent, necessitates some proper treatments due to the theoretical requirements. This study reviews the Poisson theory and investigates a more rigorous methodology for the numerical solution of the spherical integral equation by addressing many issues such as spherical-Earth model implementation, far-zone effect, Poisson kernel modification, and suitable ground data reduction scheme. We first explore the far-zone effect and search for an optimal near-zone spherical cap radius above which the truncation error is negligible. We then compare different variants of remove-restore technique with …


Triberta And Beyond: Redefining Entity Resolution With Large Language Models, Bi Foua Jan 2024

Triberta And Beyond: Redefining Entity Resolution With Large Language Models, Bi Foua

Theses and Dissertations

Entity resolution (ER) plays a pivotal role across domains by enabling data integration and quality improvement. This dissertation delves into the evolving landscape of ER, introducing innovative approaches that redefine this fundamental task. The first contribution is TriBERTa, a novel representation learning model tailored for ER. TriBERTa sets new benchmarks in entity matching and demonstrates versatility across ER processes like data blocking and resolution. Empirical evaluations on diverse datasets showcase TriBERTa’s superior performance over existing representations, including from large language models. The second contribution explores the use generative language models like GPT-3.5 and Dolly 2.0 for cross-domain entity matching using …


The Outburst Probability Index (Ww) As A New Tool In The Coal Seam Outburst Hazard Forecasting, Marcin Dreger, Piotr Celary Jan 2024

The Outburst Probability Index (Ww) As A New Tool In The Coal Seam Outburst Hazard Forecasting, Marcin Dreger, Piotr Celary

Journal of Sustainable Mining

Gas and rock outbursts are one of the most unpredictable natural hazards in Polish and worldwide underground mining. The complexity and unpredictability of this phenomenon make forecasting and underground prevention difficult to achieve. Gas-geodynamic phenomenon occurs in greater intensity in the southern part of the Upper Silesian Coal Basin (USCB) – close to the Bzie-Czechowice fault zone. The relatively low firmness of coal combined with high methane content and pressure may result in a coal seam outburst. To forecast the gas and rock outburst occurrence, the sorption capacity and gas diffusion parameters are used in Polish coal mining. To provide …