Physical Sciences and Mathematics Commons^™

Electrically Driven Reprogrammable Phase-Change Metasurface Reaching 80% Efficiency, Sajjad Abdollahramezani, Omid Hemmatyar, Mohammad Taghinejad, Hossein Taghinejad, Alex Krasnok, Ali A. Eftekhar, Christian Teichrib, Sanchit Deshmukh, Mostafa A. El-Sayed, Eric Pop, Matthias Wuttig, Andrea Alù, Wenshan Cai, Ali Adibi

Advanced Science Research Center

Phase-change materials (PCMs) offer a compelling platform for active metaoptics, owing to their large index contrast and fast yet stable phase transition attributes. Despite recent advances in phase-change metasurfaces, a fully integrable solution that combines pronounced tuning measures, i.e., efficiency, dynamic range, speed, and power consumption, is still elusive. Here, we demonstrate an in situ electrically driven tunable metasurface by harnessing the full potential of a PCM alloy, Ge₂Sb₂Te₅ (GST), to realize non-volatile, reversible, multilevel, fast, and remarkable optical modulation in the near-infrared spectral range. Such a reprogrammable platform presents a record eleven-fold change in …

Amm Problem #12279, Brad Isaacson

Publications and Research

No abstract provided.

Using Data Science Tools For Investigating Chat Logs From The Conti Ransomware Group, Boyan Kostadinov, Joseph Liu, Julio Rayme

Publications and Research

The main goal of this paper is to showcase some results from a comprehensive data analysis that we did on the cache of chat logs from the notorious ransomware group Conti. The chat logs were made publicly available on February 27, 2022. They were translated from Russian into English, and contain 393 json files with chat logs from the instant messaging service Jabber. We employ a variety of modern data science tools for text mining, natural language processing, network analysis and geospatial analysis to investigate the Conti chat logs so that we can understand the command and control structure of …

A Monolithic 3d Printed Axisymmetric Co-Flow Single And Compound Emulsion Generator, Amirreza Ghaznavi, Yang Lin, Mark Douvidzon, Adam Szmelter, Alannah Rodrigues, Malik Blackman, David Eddington, Tal Carmon, Lev Deych, Lan Yang, Jie Xu

Publications and Research

We report a microfluidic droplet generator which can produce single and compound droplets using a 3D axisymmetric co-flow structure. The design considered for the fabrication of the device integrated a user-friendly and cost-effective 3D printing process. To verify the performance of the device, single and compound emulsions of deionized water and mineral oil were generated and their features such as size, generation frequency, and emulsion structures were successfully characterized. In addition, the generation of bio emulsions such as alginate and collagen aqueous droplets in mineral oil was demonstrated in this study. Overall, the monolithic 3D printed axisymmetric droplet generator could …

Trapped Surfaces, Topology Of Black Holes, And The Positive Mass Theorem, Lan-Hsuan Huang, Dan A. Lee

Publications and Research

No abstract provided.

Satellite Evidence Of Canopy-Height Dependence Of Forest Drought Resistance In Southwestern China, Peipei Xu, Wei Fang, Tao Zhou, Hu Li, Xiang Zhao, Spencer Berman, Ting Zhang, Chuixiang Yi

Publications and Research

The frequency and intensity of drought events are increasing with warming climate, which has resulted in worldwide forest mortality. Previous studies have reached a general consensus on the size-dependency of forest resistance to drought, but further understanding at a local scale remains ambiguous with conflicting evidence. In this study, we assessed the impact of canopy height on forest drought resistance in the broadleaf deciduous forest of southwestern China for the 2010 extreme drought event using linear regression and a random forest (RF) model. Drought condition was quantified with standardized precipitation evapotranspiration index (SPEI) and drought resistance was measured with the …

Combinatorial Optimization With Photonics-Inspired Clock Models, Mostafa Honari-Latifpour, Matthew S. Mills, Mohammad-Ali Miri

Publications and Research

NP-hard combinatorial optimization problems are in general hard problems that their computational complexity grows faster than polynomial scaling with the size of the problem. Thus, over the years there has been a great interest in developing unconventional methods and algorithms for solving such problems. Here, inspired by the nonlinear optical process of q-photon down-conversion, in which a photon is converted into q degenerate lower energy photons, we introduce a nonlinear dynamical model that builds on coupled single-variable phase oscillators and allows for efficiently approximating the ground state of the classical q-state planar Potts Hamiltonian. This reduces the exhaustive search in …

Automatic Cephalometric Landmark Detection On X-Ray Images Using Object Detection, Cheng-Ho King, Yin-Lin Wang, Chia-Ling Tsai

Publications and Research

We propose a new deep convolutional cephalometric landmark detection framework for orthodontic treatment. Our proposed method consists of two major steps: landmark detection using a deep neural network for object detection, and landmark repair to ensure one instance per landmark class. For landmark detection, we modify the loss function of the backbone network YOLOv3 to eliminate the constrains on the bounding box and incorporate attention mechanism to improve the detection accuracy. For landmark repair, a triangle mesh is generated from the average face to eliminate superfluous instances, followed by estimation of missing landmarks from the detected ones using Laplacian Mesh. …

A Novel Tropical Geometry-Based Interpretable Machine Learning Method: Pilot Application To Delivery Of Advanced Heart Failure Therapies, Heming Yao, Harm Derkson, Jessica R. Golbus, Justin Zhang, Keith D. Aaronson, Jonathan Gryak, Kayvan Najarian

Publications and Research

Abstract—A model’s interpretability is essential to many practical applications such as clinical decision support systems. In this paper, a novel interpretable machine learning method is presented, which can model the relationship between input variables and responses in humanly understandable rules. The method is built by applying tropical geometry to fuzzy inference systems, wherein variable encoding functions and salient rules can be discovered by supervised learning. Experiments using synthetic datasets were conducted to demonstrate the performance and capacity of the proposed algorithm in classification and rule discovery. Furthermore, we present a pilot application in identifying heart failure patients that are eligible …

Technical Note: Novel Estimates Of The Leaf Relative Uptake Rate Of Carbonyl Sulfide From Optimality Theory, Georg Wohlfahrt, Albin Hammerle, Felix M. Spielmann, Florian Kitz, Chuixiang Yi

Publications and Research

In order to estimate the gross primary productivity (GPP) of terrestrial ecosystems from the canopy uptake of carbonyl sulfide (COS), the leaf relative uptake rate (LRU) of COS with respect to carbon dioxide needs to be known a priori. Currently, the variability of the LRU between plant species in different biomes of the world is poorly understood, making the choice of an appropriate LRU uncertain and hampering further progress towards developing COS as an alternative tracer of GPP. Here we propose a novel approach for estimating LRU based on plant optimality principles, validate it against in situ leaf gas exchange …

Topics In Analytic Number Theory And Consecutive Primitive Roots, Nelson Carella

Publications and Research

This monograph proves the existence of various configurations of $(k+1)$-tuples of consecutive and quasi consecutive primitive roots $n+a_0, n+a_1, n+a_2, ,,,, n+a_k$ in the finite field $\F_p$, where $a_0,a_1, \ldots, a_k$ is a fixed $(k+1)$-tuples of distinct integers.

High-Resolution Cryo-Electron Microscopy Structure Of Photosystem Ii From The Mesophilic Cyanobacterium, Synechocystis Sp. Pcc 6803, Christopher J. Gisriel, Jimin Wang, Jinchan Liu, David A. Flesher, Krystle M. Reiss, Hao-Li Huang, Ke R. Yang, William H. Armstrong, M. R. Gunner, Victor S. Batista, Richard J. Debus, Gary W. Brudvig

Publications and Research

Photosystem II (PSII) enables global-scale, light-driven water oxidation. Genetic manipulation of PSII from the mesophilic cyanobacterium Synechocystis sp. PCC 6803 has provided insights into the mechanism of water oxidation; however, the lack of a highresolution structure of oxygen-evolving PSII from this organism has limited the interpretation of biophysical data to models based on structures of thermophilic cyanobacterial PSII. Here, we report the cryo-electron microscopy structure of PSII from Synechocystis sp. PCC 6803 at 1.93-Å resolution. A number of differences are observed relative to thermophilic PSII structures, including the following: the extrinsic subunit PsbQ is maintained, the C terminus of the …

Cuny York College–Hosted Nasa Stem Outreach Program Graduates Over 30,000 Students – The Legacy Continues Amidst The Covid-19 Pandemic, Nazrul I. Khandaker

Publications and Research

The NASA MUREP (Minority University Research and Education Project) and SEMAA (Science, Engineering, Mathematics and Aerospace Academy) at York College CUNY (City University of New York), borough of Queens, New York City, recently earned a distinction by graduating over 30,000 underrepresented minority students since 1999 with the culmination of the fall 2021 session! African American students are leading the graduates, followed by Hispanic and Asian students being almost equal in proportion. The primary objective of both MAA (MUREP Aerospace Academy) and SEMAA is getting underrepresented minority students exposure to innovative STEM content and prepare many of them to enter higher …

Unbuilding: How Deconstruction Is Saving The Planet By Giving Building Materials A Second Life, Diana M. Ducroz

Capstones

In 2018, more than 600 million tons of construction and demolition (C&D) waste was generated in the United States, more than twice the volume of ordinary trash created by American households and businesses. Even though 80-95% of this concrete, asphalt, steel, wood, drywall, glass and brick can be reused, repurposed or recycled, a quarter of it – or 145 million tons in 2018 – ends up in landfills. Thirty million tons of wood alone – often sturdy, irreplaceable old-growth lumber – is being trashed every year.

Now, a budding ‘build reuse’ movement, made up of environmentalists, architects, historic preservationists, city …

Computational Thinking For Teachers, Susan Imberman

Open Educational Resources

This is a syllabus for a course in computational thinking. The course described introduces preservice and inservice teachers to the fundamental concepts of computer science, including web design, coding, ethics, computational thinking, course resources, etc.

Plastic Recycling Is Inefficient And Expensive, Clark S. Adomaitis

Capstones

Plastics production and incineration contributes more than 850 million metric tons to the emissions that are causing climate change. Emissions are growing at a moment when scientists and world leaders are in agreement that they need to dramatically decrease. Environmentalists say that plastic production makes up 4.5% of global greenhouse gas emissions. New plastic plants opening in the U.S. do not line up with emission reduction goals.

At the end of plastics’ lives, a lot of what we’re putting into our recycling bins isn’t getting recycled. In fact, only 18% of trash from New York City homes is actually recycled. …

Quantum Mechanics-Based Computational Chemistry Has Become A Powerful Partner In The Scientific Research Of Nitrogen-Rich Compounds, Paving The Way For Important Advances In Biochemical, Pharmacological And Other Related Fields, Dobrushe Denburg

Student Theses and Dissertations

The Computational Chemistry of Nitrogen-Rich Compounds; Insight into Pioneering Research

Nitrogen-rich functional groups have long been studied for their diversity; nitrogen can form single, double and triple bonds with itself, and will therefore exist in a very broad range of molecular arrangements. Poly-nitrogen compounds are highly energetic and electron rich, and many compounds display unique properties that allow participation in very specialized chemical reactions. Of import is their ubiquity in biological systems, and throughout the past century and currently, their biological relevance is deeply and widely explored in biochemistry and biomedicine, from their involvement in natural biological processes and complex …

Messiness: Automating Iot Data Streaming Spatial Analysis, Christopher White, Atilio Barreda Ii

Publications and Research

The spaces we live in go through many transformations over the course of a year, a month, or a day; My room has seen tremendous clutter and pristine order within the span of a few hours. My goal is to discover patterns within my space and formulate an understanding of the changes that occur. This insight will provide actionable direction for maintaining a cleaner environment, as well as provide some information about the optimal times for productivity and energy preservation.

Using a Raspberry Pi, I will set up automated image capture in a room in my home. These images will …

Measurement Of Speed Of Sound Using Smartphones, Omotolani Adelekan

Publications and Research

The goal of this experiment is to determine the speed of sound in air. To measure the speed of sound, I used two smartphones and an app called Phyphox This app uses the microphone of the smartphone to detect the time between two acoustic events The “acoustic stopwatch” tool on the app is used to measure the time between two sound signals These two signals are produced by hand clapping In this experiment, the speed of sound is determined using the time of flight method This method is based on measuring the time delay between the generation and the detection …

An Analysis Of Comparison-Based Sorting Algorithms, Jacob M. Gomez, Edgar Aponte, Brad Isaacson

Publications and Research

Our names are Edgar Aponte and Jacob Gomez and we are Applied Mathematics students at City Tech. Our mentor is Prof. Isaacson and we conducted an analysis of comparison-based sorting algorithms, meaning that they can sort items of any type for which a “less-than” relation is defined. We implemented 24 comparison-based sorting algorithms and elaborated on 6 for our poster. We analyzed the running times of these sorting algorithms with various sets of unsorted data and found that introspective sort and timsort were the fastest and most efficient, with introspective sort being the very fastest.

Analyze And Examine Wildfire Events In California, Aleena Hoodith, Sakim Zaman, Safoan Hossain, Jiehao Huang

Publications and Research

•A wildfire is an unplanned, unwanted, uncontrolled fire in an area of combustible vegetation starting in rural areas and urban areas. •Recent studies have shown that the effect of anthropogenic climate change has fueled the wildfire events, leading to an increase in the annual burned areas and number of events. •California is one of the places having the most deadliest and destructive wildfire seasons. With the global warming effect of 1°C since 1850, the 20 largest wildfires events that have occurred in California, 8 of them were in 2017. (Center For Climate And Energy Solutions) •Climate change is primarily caused …

Role Played By Edge-Defects In The Optical Properties Of Armchair Graphene Nanoribbons, Thi-Nga Do, Godfrey Gumbs, Danhong Huang, Bui D. Hoi, Po-Hsin Shih

Publications and Research

We explore the implementation of specific optical properties of armchair graphene nanoribbons (AGNRs) through edge-defect manipulation. This technique employs the tight-binding model in conjunction with the calculated absorption spectral function. Modification of the edge states gives rise to the diverse electronic structures with striking changes in the band gap and special flat bands at low energy. The optical-absorption spectra exhibit unique excitation peaks, and they strongly depend on the type and period of the edge extension. Remarkably, there exist the unusual transition channels associated with the flat bands for selected edge-modified systems. We discovered the special rule governing how the …

Me3al-Mediated Domino Nucleophilic Addition/Intramolecular Cyclisation Of 2-(2-Oxo-2-Phenylethyl)Benzonitriles With Amines; A Convenient Approach For The Synthesis Of Substituted 1-Aminoisoquinolines, Krishna M. S. Adusumalli, Lakshmi N.S. Konidena, Hima B. Gandham, Krishnaiah Kumari, Krishan R. Valluru, Satya K.R. Nidasanametla, Venkateswara R. Battula, Hari K. Namballa

Publications and Research

A simple and efficient protocol for the construction of 1-aminoisoquinolines was achieved by treating 2-(2-oxo-2- phenylethyl)benzonitriles with amines in the presence of Me 3 Al. The reaction proceeds via a domino nucleophilic addition with subsequent intramolecular cyclisation. This method provides a wide variety of substituted 1-aminoisoquinolines with good func- tional group tolerance. Furthermore, the synthetic utility of this protocol was demonstrated in the successful synthesis of the anti- tumor agent CWJ-a-5 in gram scale.

Treatment Selection Using Prototyping In Latent-Space With Application To Depression Treatment, Akiva Kleinerman, Ariel Rosenfeld, David Benrimoh, Robert Fratila, Caitrin Armstrong, Joseph Mehltretter, Eliyahu Shneider, Amit Yaniv-Rosenfeld, Jordan Karp, Charles F. Reynolds, Gustavo Turecki, Adam Kapelner

Publications and Research

Machine-assisted treatment selection commonly follows one of two paradigms: a fully personalized paradigm which ignores any possible clustering of patients; or a sub-grouping paradigm which ignores personal differences within the identified groups. While both paradigms have shown promising results, each of them suffers from important limitations. In this article, we propose a novel deep learning-based treatment selection approach that is shown to strike a balance between the two paradigms using latent-space prototyping. Our approach is specifically tailored for domains in which effective prototypes and sub-groups of patients are assumed to exist, but groupings relevant to the training objective are not …

The Temperature-Dependent Conformational Ensemble Of Sars-Cov-2 Main Protease (Mpro), Ali Ebrahim, Blake T. Riley, Desigan Kumaran, Babak Andi, Martin R. Fuchs, Sean Mcsweeney, Daniel A. Keedy

Publications and Research

The COVID-19 pandemic, instigated by the SARS-CoV-2 coronavirus, continues to plague the globe. The SARS-CoV-2 main protease, or M^pro, is a promising target for development of novel antiviral therapeutics. Previous X-ray crystal structures of M^pro were obtained at cryogenic temperature or room temperature only. Here we report a series of high-resolution crystal structures of unliganded M^pro across multiple temperatures from cryogenic to physiological, and another at high humidity. We interrogate these datasets with parsimonious multiconformer models, multi-copy ensemble models, and isomorphous difference density maps. Our analysis reveals a temperature-dependent conformational landscape for M^pro, including …

Late Pleistocene And Early Holocene Sea-Level History And Glacial Retreat Interpreted From Shell-Bearing Marine Deposits Of Southeastern Alaska, Usa, James F. Baichtal, Alia J. Lesnek, Risa J. Carlson, Nicholas S. Schmuck, Jane L. Smith, Dennis J. Landwehr, Jason P. Briner

Publications and Research

We leverage a data set of >720 shell-bearing marine deposits throughout southeastern Alaska (USA) to develop updated relative sea-level curves that span the past ~14,000 yr. This data set includes site location, elevation, description when avail-able, and 436 14C ages, 45 of which are published here for the first time. Our sea-level curves suggest a peripheral forebulge developed west of the retreating Cordilleran Ice Sheet (CIS) margin between ca. 17,000 and 10,800 calibrated yr B.P. By 14,870 ± 630 to 12,820 ± 340 cal. yr B.P., CIS mar-gins had retreated from all of southeastern Alaska’s fjords, channels, and passages. At …

Tailoring Plasmon Excitations In Alpha − T 3 Armchair Nanoribbons, Andrii Iurov, Liubov Zhemchuzhna, Godfrey Gumbs, Danhong Huang, Paula Fekete, Farhana Anwar, Dipendra Dahal, Nicholas Weekes

Publications and Research

We have calculated and investigated the electronic states, dynamical polarization function and the plasmon excitations for α − T ₃ nanoribbons with armchair-edge termination. The obtained plasmon dispersions are found to depend significantly on the number of atomic rows across the ribbon and the energy gap which is also determined by the nanoribbon geometry. The bandgap appears to have the strongest effect on both the plasmon dispersions and their Landau damping. We have determined the conditions when relative hopping parameter α of an α − T ₃ lattice has a strong effect on the plasmons which makes our material distinguished …

Crossing The Great Divide: Bridging The Researcher–Practitioner Gap To Maximize The Utility Of Remote Sensing For Invasive Species Monitoring And Management, Kelsey Parker, Arthur Elmes, Peter Boucher, Richard A. Hallett, John E. Thompson, Zachary Simek, Justin Bowers, Andrew B. Reinmann

Advanced Science Research Center

Invasive species are increasingly present in our ecosystems and pose a threat to the health of forest ecosystems. Practitioners are tasked with locating these invasive species and finding ways to mitigate their spread and impacts, often through costly field surveys. Meanwhile, researchers are developing remote sensing products to detect the changes in vegetation health and structure that are caused by invasive species, which could aid in early detection and monitoring efforts. Although both groups are working towards similar goals and field data are essential for validating RS products, these groups often work independently. In this paper, we, a group of …

Tectonic And Geotechnical Review Of Bengal Basin For Seismic Risk Assessment In Bangladesh, Mir Fazlul Karim, Jnana Ranjan Kayal, Daya Shanker, Nazrul I. Khandaker, Arif M. Sikder, M Zillur Rahman, Muhammad Qumrul Hassan

Publications and Research

Four major geotectonic provinces of the basin are recognized: 1) the continental slope to the west of the Hinge Zone, 2) the stable shelf, 3) the deep central trough (Sylhet-Hatiya) and 4) the Chittagong-Tripura fold belt to the east. The ~300 km long Dauki Fault demarcates the elevated Shillong Plateau, part of the Indian Shield to the north and the deep basin to the south. The basin experienced three strong to major intraplate earthquakes: a) 1885 Bengal earthquake (rev. Mw 6.8) close to the Hinge Zone, b) 1918 Srimangal earthquake (rev. Mw 7.1) on the Sylhet (trough) fault and c) …

Addressing The Learning Loss During The Covid-19 Pandemic Through The Adaptation Of Virtual Platforms, Nazrul I. Khandaker, Anika Nawar Mayeesha, Violeta Escandon Correa, Toralv Munro, Andrew Singh, Matthew Khargie, Ality Aghedo, Jasmin Budhan, Krishna Mahabir, Belal A. Sayeed

Publications and Research

The York College-hosted NASA MAA (MUREP AEROSPACE ACADEMY) has always played a pivotal role in minimizing the learning loss during the summer months, which was heightened during the pandemic. Support from AT&T, Con Edison and NASA enabled the MAA program at York College to offer a virtual STEM education with an earth science concentration to 1000 plus underserved K1-12 students from the community last summer, including 160 high school students. Two factors made this endeavor fruitful: allowing additional time to engage in STEM lessons and increasing self-motivation to successfully accomplish assigned tasks. Students built partnerships and resolved technical issues with …