Engineering Commons^™

Hourly Simulated Power Production Data With Snow Loss Model At Queued Utility-Scale Pv Sites Simulated As Fixed-Tilt Systems In The U.S. Eastern Interconnection For Weather Year 2014, Shelbie Wickett, Ana Dyreson

Simulated Solar Capacity Including Snow Cover in the Eastern U.S.

Using 2014 weather data, we ran PySAM power production simulations for utility-scale PV sites in the U.S. Eastern Interconnection queue. Site IDs, capacities, and locations (counties) were extracted from Lawrence Berkeley National Laboratory’s Queued Up: 2024 Edition dataset. No panel mount information was provided, so all sites were assumed to be 30-degree, fixed tilt systems. Sites’ latitudes and longitudes were assumed to be the centers of the installation counties. See queued_site_metadata.csv file for individual site metadata.

Hourly Simulated Power Production Data With Snow Loss Model At Queued Utility-Scale Pv Sites Simulated As Fixed-Tilt Systems In The U.S. Eastern Interconnection For Weather Year 2017, Shelbie Wickett, Ana Dyreson

Simulated Solar Capacity Including Snow Cover in the Eastern U.S.

Using 2017 weather data, we ran PySAM power production simulations for utility-scale PV sites in the U.S. Eastern Interconnection queue. Site IDs, capacities, and locations (counties) were extracted from Lawrence Berkeley National Laboratory’s Queued Up: 2024 Edition dataset. No panel mount information was provided, so all sites were assumed to be 30-degree, fixed tilt systems. Sites’ latitudes and longitudes were assumed to be the centers of the installation counties. See queued_site_metadata.csv file for individual site metadata.

Hourly Simulated Power Production Data With Snow Loss Model At Queued Utility-Scale Pv Sites Simulated As Fixed-Tilt Systems In The U.S. Eastern Interconnection For Weather Year 2019, Shelbie Wickett, Ana Dyreson

Simulated Solar Capacity Including Snow Cover in the Eastern U.S.

Using 2019 weather data, we ran PySAM power production simulations for utility-scale PV sites in the U.S. Eastern Interconnection queue. Site IDs, capacities, and locations (counties) were extracted from Lawrence Berkeley National Laboratory’s Queued Up: 2024 Edition dataset. No panel mount information was provided, so all sites were assumed to be 30-degree, fixed tilt systems. Sites’ latitudes and longitudes were assumed to be the centers of the installation counties. See queued_site_metadata.csv file for individual site metadata.

Hourly Simulated Power Production Data With Snow Loss Model At Queued Utility-Scale Pv Sites Simulated As Fixed-Tilt Systems In The U.S. Eastern Interconnection For Weather Year 2021, Shelbie Wickett, Ana Dyreson

Simulated Solar Capacity Including Snow Cover in the Eastern U.S.

Using 2021 weather data, we ran PySAM power production simulations for utility-scale PV sites in the U.S. Eastern Interconnection queue. Site IDs, capacities, and locations (counties) were extracted from Lawrence Berkeley National Laboratory’s Queued Up: 2024 Edition dataset. No panel mount information was provided, so all sites were assumed to be 30-degree, fixed tilt systems. Sites’ latitudes and longitudes were assumed to be the centers of the installation counties. See queued_site_metadata.csv file for individual site metadata.

Hourly Simulated Power Production Data With Snow Loss Model At Queued Utility-Scale Pv Sites Simulated As Fixed-Tilt Systems In The U.S. Eastern Interconnection For Weather Year 2022, Shelbie Wickett, Ana Dyreson

Simulated Solar Capacity Including Snow Cover in the Eastern U.S.

Using 2022 weather data, we ran PySAM power production simulations for utility-scale PV sites in the U.S. Eastern Interconnection queue. Site IDs, capacities, and locations (counties) were extracted from Lawrence Berkeley National Laboratory’s Queued Up: 2024 Edition dataset. No panel mount information was provided, so all sites were assumed to be 30-degree, fixed tilt systems. Sites’ latitudes and longitudes were assumed to be the centers of the installation counties. Seequeued_site_metadata.csv file for individual site metadata.

Targeted Delivery Of Rapamycin Via Epidermal Growth Factor Receptors In Pancreatic Cancer Cells Inhibits Cell Proliferation And Induces Apoptosis, Adeolu S. Oluremi, Christofer Baldwin, Nickolas L. Gustavision, Mujeebat Bashiru, Adeniyi Nsiah Oyebade, Noureen Siraj, Raj Raghavendra Rao, N. Ali

Biomedical Engineering Faculty Publications and Presentations

Pancreatic cancer (PC) is aggressive and deadly; most PC cells overexpress an epidermal growth factor receptor (EGFR). EGFR-targeting peptide (GE11) was conjugated to gold nanoparticles (AuNPs) for delivering rapamycin (Rap), an mTOR inhibitor that reduces proliferation and induces apoptosis. Biophysical techniques confirmed the conjugation. Rap loading efficiency was 41.5%, with sustained release at a lower pH. Conjugates showed higher uptake in PANC-1 cells than unmodified AuNPs. It also inhibited proliferation and induced apoptosis via pathways involving reactive oxygen species, mitochondrial damage, and caspase activation. This approach represents a promising nanoparticle-based therapeutic strategy targeting PC cells, utilizing GE11-EGFR interactions to minimize …

Photocatalytic Self-Pumping Membranes, Lily D. Farmer, David Warsinger, Sudharshan Anandan

Discovery Undergraduate Interdisciplinary Research Internship

The physics of nanofiltration is not well understood, as many types of membranes and filters exist, but they all interact very differently with the substance they are filtering. This research investigates membranes that can autonomously pump fluid through catalytic reactions. The first set of experiments was to collect zeta potential measurements as zeta potential is a critical property that directly affects fluid transport. Zeta potential was measured using the Anton Parr SURPASS 3, which measures the sample by streaming a given solution through a channel of membranes and uses the Smoluchowski equation to return the zeta potential value. Measurements were …

Flight Instructor Enhanced Qualification Training Program, Brendan Aug

Aviation Student Publications

Due to December 2024 regulatory changes made to 14 CFR Part 61.195(h)— Qualifications to provide ground or flight training to initial flight instructor applicants—a new training program, titled the Flight Instructor Enhanced Qualification Training Program (FIEQTP), must be developed under 61.195(h)(3).

The purpose of this packet is, in response to regulatory changes, to conduct a thorough training needs analysis, and utilizing its conclusions, develop a new 14 CFR Part 141 course and assessment plan that meets the requirements of Part 61.195(h)(3) Flight instructor enhanced qualification training program.

Analysis Of A Saline Dust Storm From The Aralkum Desert – Part 2: Atmospheric Flow Precursors In The Euro-Atlantic Region, Xin Xi

Michigan Tech Publications

Wind-blown dust emissions from the man-made Aralkum Desert pose significant environment and human health risks across Central Asia. Yet, little is known about the atmospheric circulation patterns favoring dust outbreaks from the region. This study examines the role of upstream atmospheric blocking and recurrent transient Rossby wave packets (RWPs) in initiating a severe dust storm from the Aralkum Desert in May 2018. Results show that the dust event was triggered by an unusual early-summer cold air outbreak and attendant postfrontal northerly winds reaching 24–31 m/s. The compound cold air and dust outbreaks were preceded by repeated meridional flow amplification linked …

Targeting Poor Solubility Of Docetaxel: Computational Screening Of Ionic Liquids Using Cosmo-Rs, Najihah Mohd Noor, Amal A.M. Elgharbawy, Huma Warsi Khan, Yumi Zuhanis Has-Yun Hashim, Muhammad Moniruzzaman, Mohd Firdaus Abd. Wahab, Hamzah Mohd Salleh, Siti Nur Idayu Matusin

Publications and Research

Docetaxel (DTX), a chemotherapeutic agent widely used in cancer treatment, has limited therapeutic efficacy owing to its poor oral absorption and low bioavailability. This study aims to improve DTX solubility by predicting its compatibility with ionic liquids (ILs) using conductor-like screening model for real solvents (COSMO-RS) computational modelling. A library of 340 ILs comprising 17 cations and 20 anions was screened for their potential to dissolve DTX, with a particular focus on imidazolium-based ILs that enhance its solubility and pertinence to cytotoxic applications. Computational analysis identifies ILs containing cations such as 1-methylimidazolium [MIM] and 1,3-dimethylimidazolium [DMIM] and anions such as …

Enhanced Energy Harvesting From Nf-Pvdf Piezoelectric Material For Wearable Electronics: I– V Characterization And Charge-Discharge Performance, Ahmed Emara, Afaf Farag, Gehad Ali, Mohamed Mamdouh, Sameh O. Abdellatif, Khaled Nassar, Tamer Hamoud

Electrical Engineering

This study explores the utilization of fabricated piezoelectric polyvinylidene fluoride nanofiber (NF-PVDF) materials in wearable electronic sensing applications by investigating their current-voltage ( I − V ) characteristics under controlled ultra-low-frequency excitation forces. The results demonstrate a significant power harvesting capability, achieving an output power of 0.12 µW/mm2 at an operating point of 5.04 V and 7.7 µA. Additionally, the piezoelectric harvester was integrated into a charging-discharge circuit alongside a rectifier capacitor and a typical IoT wearable sensor, leveraging the advantages of a flexible substrate. Experimental measurements of the charging and discharging curves confirm the effective energy management of the …

Preparation And Characterization Of Electrospun Pvdf-Based Nanocomposite Fibers For Energy Harvesting And Storage Applications, Ahmed Ramzy, Electrochemistry And Corrosion Laboratory, Physical Chemistry Department, National Research Centre, Dokki, Cairo, 12622, Egypt, Ahmed M. El-Mahalawy

Nanotechnology Research Centre

This study introduces the development of multifunctional electrospun polyvinylidene fluoride (PVDF) composite films doped with potassium octatitanate (KTO) for advanced energy applications. The research tackles key challenges in energy generation and storage through innovative material design and detailed characterization. Adding 0.2 wt% KTO to PVDF electrospun fibers resulted in a notable increase in crystallinity to 78.51 %, marking a significant enhancement in material properties. Structural analysis using X-ray diffraction and Fourier transform infrared spectroscopy confirmed optimal phase composition, while morphological features were verified through field emission scanning electron microscopy. The composite films showed exceptional electrochemical performance, with bulk electrolyte resistance …

Deformation And Earthquake Potential On The North America - Caribbean - Cocos Triple Junction In Guatemala, Jeremy Maurer, Andreas Eckert, Qiaoqi Sun, Jonathan Obrist-Farner

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The triple junction between the Cocos (CO), North American (NA), and Caribbean (CA) tectonic plates in Guatemala is a region of high seismic risk and includes many large faults and historic earthquakes. Previous analyses of the tectonic system have been overly simplified, resulting in discrepancies between geologically derived and geodetic models of fault slip rate. This study leverages available geodetic, seismic, and geologic data to develop new strain rate maps and faulting models for the region. We find that locking on the regional faults matches historic reports of large earthquakes and that multiple minor fault segments are active and accommodate …

Uptake, Distribution, And Activity Of Pluronic F68 Adjuvant In Wheat And Its Endophytic Bacillus Isolate, Anthony Cartwright, Mohammad Zargaran, Anagha Wankhade, Astrid Jacobson, Joan E. Mclean, Anne J. Anderson, David W. Britt

Biological Engineering Student Research

Surfactants are widely utilized in agriculture as emulsifying, dispersing, anti-foaming, and wetting agents. In these adjuvant roles, the inherent biological activity of the surfactant is secondary to the active ingredients. Here, the hydrophilic non-ionic surface-active tri-block copolymer Pluronic^® F68 is investigated for direct biological activity in wheat. F68 binds to and inserts into lipid membranes, which may benefit crops under abiotic stress. F68’s interactions with Triticum aestivum (var Juniper) seedlings and a seed-borne Bacillus spp. endophyte are presented. At concentrations below 10 g/L, F68-primed wheat seeds exhibited unchanged emergence. Root-applied fluorescein-F68 (fF68) was internalized in root epidermal cells and …

Investigating The Impact Of Agent Openness On Planning In Multi-Agent Systems, Bala Subramanyam Duggirala

School of Computing: Dissertations, Theses, and Student Research

Multi-agent systems (MAS) possess significant potential for modeling real-world scenarios requiring coordinated actions (like wildfire fighting or ridesharing) among autonomous entities or agents (e.g., wildfire fighting agents) in complex, dynamic environments. Effective decision-theoretic planning (where each agent must carefully consider both the immediate and the future situations or states, and coordinate with the other agents (neighbors) to evaluate what needs to be done at present) within MAS, especially multiagent planning, where the planning agent directly models its neighbors in order to estimate their optimal actions, is critical, yet challenged by factors like partial observability, openness, and diverse agent types with …

Modeling The Influence Of Silicon Content On Electrochemical Performance Of Silicon-Graphite Blended Electrodes Considering Voltage Hysteresis, Mohamed Atwair, Paul T. Coman, Ralph E. White

Faculty Publications

Silicon, with its high specific capacity, is a highly promising material for lithium-ion battery anodes. To enhance durability, it is commonly combined with graphite in composite anodes. Despite this, the electrochemical dynamics between silicon and graphite are not yet fully understood. Modeling serves as an important tool for analyzing and improving batteries, but current models lack comprehensive representation of the coupled electrochemical and structural behavior of silicon-graphite blended electrodes. Herein, we present a comprehensive model for blended Si/Gr electrodes that incorporates the distinct properties and kinetics of each material. Our approach accounts for the dependence of electrode thickness and solid …

Influence Of Zinc Oxide Nanoparticles On The Efficiency Of Oxytetracycline Removal From Wastewater Using Continuous Catalytic Ozonation, Sarmad Al-Anssari, Hassanain A. Hassan, Maha K. Mohsin, Ahmed A. Mohammed

Research outputs 2022 to 2026

Antibiotics must be fully eliminated before they are released into the environment. In most cases, conventional wastewater treatment systems are not built to handle polar microcontaminants such as antibiotics. Oxytetracycline (OTC) is one of these antibiotics, an environmental hazard contaminant in aqueous solutions. Therefore, an advanced treatment method is needed for wastewater contaminated with antibiotics. In this study, we employed zinc oxide nanoparticles (ZnO), and the catalytic ozonation procedure was employed to increase the ozonation efficiency. A continuous experiment was carried out to compare the effectiveness of catalytic and single ozonation in degrading OTC in a continuous reactor. The flow …

Single-Step Conversion Of Metal Impurities In Cnts To Electroactive Metallic Nitride Nanoclusters For Electrochemical Co2 Reduction, Ahmed Badreldin, John Pellessier, Francisco Alejandro Ospina Acevedo, Siyuan Fang, Carter Racine, Jin Feng, Alvin Chang, Yulu Ge, Yang Gang, Shengyao Wang, Xiaokun Yang, Sergei Ivanov, Zhenxing Feng, Yun Hang Hu, Perla B. Balbuena, Ying Li

Michigan Tech Publications

A novel single-step low-temperature pyrolysis method is developed to efficiently remove encapsulated Ni nanoparticles (NPs, 10–50 nm) from both regular-grade (< 5 wt.% metal impurities) and industrial-grade (< 10 wt.% metal impurities) carbon nanotubes (CNTs). This approach eliminates the need for conventional multi-step purification processes, which often involve high-temperature corrosive gas oxidation and acid washing. The new strategy transforms and redistributes encapsulated Ni-NPs into homogeneously sized nanoclusters (NCs, ≈1 nm) that are evenly dispersed on the surface of CNTs. Surface and bulk sensitive spectroscopic analyses reveal the predominant formation of Ni3N-NCs, along with some metallic Ni-NCs. The treated materials demonstrate exceptional electroactivity toward CO2 reduction to CO, with the best-performing CNT-PTFE-Mel-650 sample achieving an ultra-low onset overpotential of −19 mV and 98% CO selectivity in a current density range of 100–700 mA cm⁻². This NC catalyst demonstrates 25% lower voltage at 700 mA cm⁻² compared to the single atom catalyst (SAC) control. Experimentally verified ab initio molecular dynamics (AIMD) models are simulated, and subsequent density functional theory (DFT) calculations further support the thermodynamic stability of Ni3N-NCs and their favorability for CO2 reduction. This work establishes a new method for creating ligand-free electroactive NCs for efficient electrochemical reactions.

Modeling Self-Discharge In Li/S Batteries Through Electrochemical Anode Reactions: A Theoretical Perspective, Ralph E. White, Paul T. Coman

Faculty Publications

The growing demand for high-energy-density batteries has renewed interest in lithium–sulfur (Li/S) systems, which offer significant advantages but suffer from severe self-discharge during rest. While prior studies attribute this degradation to chemical parasitic reactions or polysulfide shuttling, they overlook the inherently electrochemical nature of anode-side processes. In this work, a 1D physics-based model of a Li/S battery was developed to explicitly incorporate lithium-metal oxidation and the stepwise electrochemical reduction of polysulfides at the anode. Using COMSOL Multiphysics, galvanostatic discharge followed by open-circuit rest under two conditions was analyzed - with and without parasitic anode reactions. The results show that when …

A Descriptive Case Study On How Suburban Texas Police Department Drone Use Conforms To Public Opinion, Terrill Brett Spell

Doctoral Dissertations and Projects

The purpose of this qualitative case study was to describe the use of drones by suburban police departments in Texas, and its central research question asked how that drone use aligns with what prior research found the public supports. The research design used a holistic multiple-case approach that involved interviewing police officers who use drones as part of their law enforcement responsibilities. Relevant theoretical frameworks were social contract theory, Packer’s theory on law enforcement, and evidence-based policing theory. Data collection involved semistructured interviews of 13 officers representing the same number of Texas suburban police departments. The data collected and analyzed …

A Longitudinal Analysis Of Morphological Shape Variation Of Spleen In Patients With Fontan Surgery, Varatharajan Nainamalai, Håvard Bjørke Jenssen, Mostafa Rezaeitaleshmahalleh, Djinaud Prophete, Jordan Gosnell, Sarah Khan, Marcus Haw, Jingfeng Jiang, Joseph Vettukattil

Michigan Tech Publications

Background: Splenic size serves as a surrogate biomarker for predicting portal vein hyper-tension and liver abnormalities in subjects with Fontan Associated Liver Disease (FALD). We analyze the long-term shape variation of the spleen in FALD subjects using morphological shape features of radiomic features. Methods: We used 154 (84 from computed tomography and 70 from magnetic resonance) image volumes obtained from 36 individuals who underwent stage 3 Fontan procedure and 145 computed tomography images from controls to assess splenomegaly. To understand the splenomegaly, thirteen shape features of the spleen over three 10-year intervals, and variations between controls and FALD subjects were …

Quantifying Electrokinetics Of Naca0.6V6O163h2O Cathode In Aqueous Zinc-Ion Batteries With Znso4 Electrolyte, Shichen Sun, Boyu Wang, Kevin Huang

Faculty Publications

Aqueous zinc-ion batteries (AZIBs) have been actively studied in recent years as a promising solution for next-generation stationary energy storage due to their inherent safety, low cost, and high energy density. However, their practical deployment remains hindered by the limited cycling stability of cathode materials. Overcoming this challenge requires a detailed understanding of cathodic electrokinetics and degradation mechanisms. In this study, we investigate the electrokinetic behavior of a NaCa_0.6V₆O₁₆3H₂O (NaCaVO) cathode in ZnSO4 electrolyte through a combined application of the galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS). For the …

Hourly Sulfur Dioxide Observations Over North America: First Retrieval Results From Tempo, Can Li, Nickolay A. Krotkov, Joanna Joiner, Simon Carn, Vitali Fioletov, Chris Mclinden, Debora Griffin, Xiong Liu, Heesung Chong

Michigan Tech Publications

We present the first sulfur dioxide (SO2) retrievals from Tropospheric Emissions: Monitoring of Pollution (TEMPO), the first geostationary atmospheric composition sensor to cover North America, along with some potential applications of TEMPO SO2 data. We show that high resolution (∼10 km²) TEMPO measurements can be used to produce good quality SO2 retrievals with relatively small noise and biases. We demonstrate that hourly TEMPO data are useful for monitoring volcanic hazards, by providing frequent updates on the plume location and additional information on the plume height or winds. With the large number of measurements from TEMPO, it is also …

Quantifying Electrokinetics Of Naca0.6V6O16·3h2O Cathode In Aqueous Zinc-Ion Batteries With Znso4 Electrolyte, Shichen Sun, Boyu Wang, Kevin Huang

Faculty Publications

Aqueous zinc-ion batteries (AZIBs) have been actively studied in recent years as a promising solution for next-generation stationary energy storage due to their inherent safety, low cost, and high energy density. However, their practical deployment remains hindered by the limited cycling stability of cathode materials. Overcoming this challenge requires a detailed understanding of cathodic electrokinetics and degradation mechanisms. In this study, we investigate the electrokinetic behavior of a NaCa_0.6V₆O₁₆·3H₂O  (NaCaVO) cathode in ZnSO₄ electrolyte through a combined application of the galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS). For …

Collaborative Class Zine: Weekly Reflection Assignment With Powerpoint Template, Brett Whysel

Open Educational Resources

Abstract

This collaborative class zine assignment uses a shared PowerPoint format to deepen student learning while building community. Students contribute visual reflections (graphics, diagrams, quotes, or doodles) weekly or periodically throughout the semester. Faculty provide reflection prompts about key takeaways and unclear concepts (sample prompts included). The resource includes both sample LMS instructions and a ready-to-use PowerPoint zine template that works across all disciplines. By combining metacognitive reflection with creative expression, students consolidate learning by finding new connections and applications. The collaborative format creates community connections and joy while students learn from peers' diverse perspectives.

The Impact Of Clean Energy Technology Incentives On Mineral Demand: An Economic Framework For Measuring Response, Hamdiya Orleans-Boham, Mahelet G. Fikru, Kwame Awuah-Offei

Economics Faculty Research & Creative Works

The existing literature establishes the link between clean energy technology (CET) expansion and rising mineral demand but lacks a comprehensive analysis of the transmission mechanisms through which CET policy incentives particularly production and consumption subsidies affect mineral markets. This study addresses the gap by developing an economic model where a CET producer optimally determines mineral input demand and production volume, where the concept of elasticity is used to measure the response of mineral demand to policy incentives. Analytical results demonstrate that the elasticity of mineral demand with respect to CET policies is highly sensitive to returns to scale of CET …

A Perovskite Nanocomposite And Self-Assembled Nanoparticle-Decorated Cathode For Low Temperature Sofcs, Chunyang Yang, Guoan Wang, Xingjian Xue

Faculty Publications

One-pot route synthesis of an A-site Sm-doped simple perovskite with nominal composition Sm_0.10Ba_0.90Co_0.8Fe_0.2O_3−δ leads to a novel perovskite nanocomposite containing ∼90% A-site cation deficient cubic simple perovskite Ba0.925(Co/Fe)0.962Sm0.038O_3−δ and ∼10% orthorhombic layered perovskite SmBa(Co/Fe)₂O_5+δ. The synergy of the two phases in the nanocomposite results in high electrochemical kinetic properties at low temperatures. With the novel perovskite nanocomposite, a surface nanoparticle-decorated nanocomposite cathode is self-assembled through a one-step sintering process. The corresponding anode-supported cell delivers a peak power density of 1271 mW cm^{−2 …}

Recent Advances In Modelling Of Frost Formation For Mechanical Systems, Yong Tao

Mechanical Engineering Faculty Publications

The physics underlying frost and ice formation has been extensively studied over the past few decades, with significant contributions to our understanding of this phenomenon. These insights have primarily been applied to engineering systems with refrigerated surfaces, such as refrigerators, freezers and heat pumps of various sizes. Despite considerable progress, the dynamic and complex mechanisms governing frost and ice formation remain an active area of research, as competing factors continue to challenge predictive accuracy. The increasing interest from stakeholders in reducing energy consumption and carbon footprints in mechanical systems further underscores the importance of advancing modelling and simulation capabilities in …

Predicting Sleep And Sleep Stage In Children Using Actigraphy And Heartrate Via A Long Short-Term Memory Deep Learning Algorithm: A Performance Evaluation, Robert Weaver Med, Phd, James White, Olivia Finnegan, Hongpeng Yang, Zifei Zhong, Keagan Kiely, Catherine Jones, Yan Tong, Srihari Nelakuditi, Rahul Ghosal, David E. Brown, Russell R. Pate Ph.D., Gregory J. Welk, Massimiliano De Zambotti, Yuan Wang, Sarah Burkart, Elizabeth L. Adams Phd, Bridget Armstrong, Michael Beets Med, Mph, Phd

Faculty Publications

Children's ambulatory sleep is commonly measured via actigraphy. However, traditional actigraphy measured sleep (e.g., Sadeh algorithm) struggles to predict wake (i.e., specificity, values typically < 70) and cannot predict sleep stages. Long short-term memory (LSTM) is a machine learning algorithm that may address these deficiencies. This study evaluated the agreement of LSTM sleep estimates from actigraphy and heartrate (HR) data with polysomnography (PSG). Children (N = 238, 5–12 years,52.8% male, 50% Black 31.9% White) participated in an overnight laboratory polysomnography. Participants were referred be-cause of suspected sleep disruptions. Children wore an ActiGraph GT9X accelerometer and two of three consumer wearables(i.e., Apple Watch Series 7, Fitbit Sense, Garmin Vivoactive 4) on their non-dominant wrist during the polysomnogram. LSTM estimated sleep versus wake and sleep stage (wake, not-REM, REM) using raw actigraphy and HR data for each 30-s epoch. Logistic regression and random forest were also estimated as a benchmark for performance with which to compare the LSTM results. A 10-fold cross-validation technique was employed, and confusion matrices were constructed. Sensitivity and specificity were calculated to assess the agreement between research-grade and consumer wearables with the criterion polysomnography. For sleep versus wake classification, LSTM outperformed logistic regression and random forest with accuracy ranging from 94.1to 95.1, sensitivity ranging from 94.9 to 95.9 across different devices, and specificity ranging from 84.5 to 89.6. The addition of HR improved the prediction of sleep stages but not binary sleep versus wake. LSTM is promising for predicting sleep and sleep staging from actigraphy data, and HR may improve sleep stage prediction.

Solar Absorption Cooling Systems – A Case Study In Egypt, Hesham Safwat, Iman El-Mahallawi

Mechanical Engineering

Climate change with Egypt’s increasingly hot weather and plans towards energy transition, addressing an approach for clean HVAC (Heating, Ventilation, and Air Condition) solutions is becoming requisite. This paper examines the potential of utilizing solar absorption cooling systems in institutional buildings by presenting a case study of a proposed solar absorption cooling system for a library building with an area of 4402 m2, located at the British University in Egypt. The proposed solution is to replace 30% of the existing conventional air conditioning units with a hot-water driven single-effect absorption chiller powered by solar thermal vacuum tube solar collectors, coupled …