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Climatology archive and accurate weather forecasts depend strongly on availability of observed properties of the atmosphere and can benefit significantly from higher temporal resolution of measurements on atmospheric temperature, pressure, relative humidity, wind speed and direction. Weather ballooning with radiosonde payloads can provide these data with relatively low initial capital costs while providing educational benefits for students, especially undergraduates in STEM majors. For example, recently we conducted a field campaign, Atmospheric Dynamics over the Gulf Stream (ADOGS), by launching radiosondes hourly during January 6 – 9, 2025 from New Haven, Connecticut. We observed rapid changes in the troposphere during that week and provided a great weather ballooning educational platform for students from Northeastern US, especially those at Primarily Undergraduate Institutions (PUIs) and Emerging Research Institutions (ERIs). Our results provide practical field experiences that may benefit the planning of future radiosonde campaigns, especially those with ballooning education and student engagement focuses, by the high-altitude ballooning (HAB) community. 

Weather ballooning with radiosonde payloads can provide field-based, observational meteorological data for operational weather forecasts and research on the atmosphere and the climate. Despite the relatively low initial capital costs when comparing to aircraft/satellite methods, the costs of ground stations/trackers (GSTs) receiving and decoding the radiosonde telemetry may pose a significant financial challenge to institutions with limited resources and to flight missions with high temporal resolution (launch intervals of less than 3 hours). We conducted a Radiosonde and Ground Station/Tracker Intercomparison (RGSTI) study in April 2025 to evaluate some of the current low-cost GSTs options and the Sondehub (SH) multi-receiver radiosonde tracking network. Although yielding varied data based on radiosonde models, SH demonstrated less dependence on antenna alignment, longer radiosonde tracking and data telemetry, and the capacity of tracking multiple radiosondes with minimal hardware requirements and financial barriers. Our results provide a comprehensive review on the data matrix of different radiosonde/GST combinations and recommendations that may benefit the planning of future high temporal resolution radiosonde campaigns by the high altitude ballooning community. 

Degradable polymers are promising materials for use to reduce plastic waste and advance biomedical applications. However, to meet the demands of specific applications, tailoring the properties of degradable polymers through precise modification of their chemical structures is critical. Herein, we present a new class of degradable and functionalizable polyacetals synthesized by the ring-opening metathesis copolymerization (ROMP) of two commercially available monomers: dimethyl oxanorbornadiene-2,3-dicarboxylate (OND) and 4,7-dihydro-1,3-dioxepin (DXP). The resulting polyacetals are not only acid-degradable but also readily and efficiently functionalizable via thia–Michael addition, yielding degradable polymer materials with various functional groups and tunable thermal properties. 

Here we report the design and synthesis of acid-degradable and functionalizable polymers via alternating ring-opening metathesis copolymerization of oxanorbornadiene dicarboxylate and 2,3-dihydrofuran. The resulting polymers can undergo post-polymerization modification through... 

Biomass-derived polymer materials are emerging as sustainable and low-carbon footprint alternatives to the current petroleum-based commodity plastics. In the past decade, the ring-opening metathesis polymerization (ROMP) technique has been widely used for the polymerization of cyclic olefin monomers derived from biorenewable resources, giving rise to a diverse set of biobased polymer materials. However, most synthetic biobased polymers made by ROMP are nondegradable because of their all-carbon backbones. Herein, we present a modular synthetic strategy to acid-degradable poly(enol ether)s via ring-opening metathesis copolymerization of biorenewable oxanorbornenes and 3,4-dihydropyran (DHP). 1H NMR analysis reveals that the percentage of DHP units in the resulting copolymers gradually increases as the feed ratio of DHP to oxanorbornene increases. The composition of the copolymers plays a pivotal role in governing their thermal properties. Thermogravimetric analysis shows that an increasing percentage of DHP results in a decrease in the decomposition temperatures, suggesting that the incorporation of enol ether groups in the polymer backbone reduces the thermal stability of the copolymers. Moreover, a wide range of glass transition temperatures (16–165 °C) can be achieved by tuning the copolymer composition and the oxanorbornene structure. Critically, all of the poly(enol ether)s developed in this study are degradable under mildly acidic conditions. A higher incorporation of DHP in the copolymer leads to enhanced degradability, as evidenced by smaller final degradation products. Altogether, this study provides a facile approach for synthesizing biorenewable and degradable polymer materials with highly tunable thermal properties desired for their potential industrial applications. 

The concentration of the stratospheric ozone layer is of great interest to the atmospheric science community, since it is critical in blocking the harmful UV radiation from the sun. Typically, regular weather balloons with Electrochemical Cell (ECC) ozonesondes are used to determine the vertical profile of ozone column concentration within a flight time of ~2 hours, with a limited fraction of the data relevant to the ozone layer. Therefore, it would be ideal if ozonesonde flights can be maintained within the ozone layer (~60,000 to 80,000 ft) to maximize the efficiency in data acquisition, especially considering the rising costs of ozonesonding and high-altitude ballooning. We adapted the vented balloon with altitude-control flight capability from the Nationwide Eclipse Ballooning Program (NEBP) for atmospheric ozonesonding and deployed a commercial ECC ozonesonde payload with this approach from Central Texas during the 2024 total solar eclipse in the hope of (1) field testing the performance and application potential of vented balloons in horizontal ozone layer profiling and (2) monitoring the stratospheric ozone layer during the solar eclipse for an extended period of time. The adapted vent valve successfully lowered the balloon from 71,000 ft to 41,000 ft within minutes and demonstrated promising performance in the field. Unfortunately, unexpected radio communication difficulties were experienced from six hours before the totality to two hours after, leaving the second research objective largely unobtainable. 

Degradable polymers made via ring-opening metathesis polymerization (ROMP) hold tremendous promise as eco-friendly materials. However, most of the ROMP monomers are derived from petroleum resources, which are typically considered less sustainable compared to biomass. Herein, we present a synthetic strategy to degradable polymers by harnessing alternating ROMP of biomass-based cyclic olefin monomers including exo-oxanorbornenes and cyclic enol ethers. A library of well-defined poly(enol ether)s with modular structures, tunable glass transition temperatures, and controlled molecular weights was achieved, demonstrating the versatility of this approach. Most importantly, the resulting copolymers exhibit high degrees of alternation, rendering their backbones fully degradable under acidic conditions. 

The current insufficient recycling of commodity polymer waste has resulted in pressing environmental and human health issues in our modern society. In the quest for next-generation polymer materials, chemists have recently shifted their attention to the design of chemically recyclable polymers that can undergo depolymerization to regenerate monomers under mild conditions. During the past decade, ring-closing metathesis reactions have been demonstrated to be a robust approach for the depolymerization of polyolefins, producing low-strain cyclic alkene products which can be repolymerized back to new batches of polymers. In this review, we aim to highlight the recent advances in chemical recycling of polyolefins enabled by ring-closing metathesis depolymerization (RCMD). A library of depolymerizable polyolefins will be covered based on the ring size of their monomers or depolymerization products, including five-membered, six-membered, eight-membered, and macrocyclic rings. Moreover, current limitations, potential applications, and future opportunities of the RCMD approach will be discussed. It is clear from recent research in this field that RCMD represents a powerful strategy towards closed-loop chemical recycling of novel polyolefin materials. 

Abstract It is shown that a decaying neutralino in a supergravity unified framework is a viable candidate for dark matter. Such a situation arises in the presence of a hidden sector with ultraweak couplings to the visible sector where the neutralino can decay into the hidden sector’s lightest supersymmetric particle (LSP) with a lifetime larger than the lifetime of the universe. We present a concrete model where the MSSM/SUGRA is extended to include a hidden sector comprised of $$U(1)_{X_1} \times U(1)_{X_2}$$ U ( 1 ) X 1 × U ( 1 ) X 2 gauge sector and the LSP of the hidden sector is a neutralino which is lighter than the LSP neutralino of the visible sector. We compute the loop suppressed radiative decay of the visible sector neutralino into the neutralino of the hidden sector and show that the decay can occur with a lifetime larger than the age of the universe. The decaying neutralino can be probed by indirect detection experiments, specifically by its signature decay into the hidden sector neutralino and an energetic gamma ray photon. Such a gamma ray can be searched for with improved sensitivity at Fermi-LAT and by future experiments such as the Square Kilometer Array (SKA) and the Cherenkov Telescope Array (CTA). We present several benchmarks which have a natural suppression of the hadronic channels from dark matter annihilation and decays and consistent with measurements of the antiproton background.