An inexpensive platform has been developed for automated measurements of air quality. Low-cost sensors for aerosol optical thickness, ozone, temperature, relative humidity, and pressure were combined with a low-cost computer (Raspberry Pi) for automated monitoring. The Raspberry Pi is well-suited to automated measurements because of: (1) its low cost, (2) its low power consumption, (3) its ability to communicate over Ethernet or wireless networks and (4) its ability to interface with many sensors through analog-to-digital converters or directly through Universal Serial Bus (USB), serial port, Inter-Integrated Circuit (I2C), and Serial Peripheral Interface (SPI). This setup is appropriate for use in, e.g., undergraduate atmospheric research groups, where the cost of typical automated sensors is prohibitively expensive. We report measurements taken over a two-month period which includes evidence of high nighttime ozone due to being downwind of a forest fire. This platform can be expanded to enable other atmospheric measurements from a number of sensors.

SummaryScholars worldwide leverage science gateways/virtual research environments (VREs) for a wide variety of research and education endeavors spanning diverse scientific fields. Evaluating the value of a given science gateway/VRE to its constituent community is critical in obtaining the financial and human resources necessary to sustain operations and increase adoption in the user community. In this article, we feature a variety of exemplar science gateways/VREs and detail how they define impact in terms of, for example, their purpose, operation principles, and size of user base. Further, the exemplars recognize that their science gateways/VREs will continuously evolve with technological advancements and standards in cloud computing platforms, web service architectures, data management tools and cybersecurity. Correspondingly, we present a number of technology advances that could be incorporated in next‐generation science gateways/VREs to enhance their scope and scale of their operations for greater success/impact. The exemplars are selected from owners of science gateways in the Science Gateways Community Institute (SGCI) clientele in the United States, and from the owners of VREs in the International Virtual Research Environment Interest Group (VRE‐IG) of the Research Data Alliance. Thus, community‐driven best practices and technology advances are compiled from diverse expert groups with an international perspective to envisage futuristic science gateway/VRE innovations.

The future for science gateways warrants exploration as we consider the possibilities that extend well beyond ’science’ and high-performance computing into new interfaces, applications and user communities. In this paper, we look retrospectively at the successes of representative gateways thus far. This serves to highlight existing gaps gateways need to overcome in areas such as accessibility, usability and interoperability, and in the need for broader outreach by drawing insights from technology adoption research. We explore two particularly promising opportunities for gateways - computational social sciences and virtual reality – and make the case for the gateway community to be more intentional in engaging with users to encourage adoption and implementation, especially in the area of educational usage. We conclude with a call for focused attention on legal hurdles in order to realize the full future potential of science gateways. This paper serves as a roadmap for a vision of science gateways in the next ten years.

Students used an Excel spreadsheet and a Jupyter notebook located at https://chemcompute.org/jupyterhub/ to generate data in lieu of face-to-face laboratory instruction during COVID-19. This communication discusses strengths and weaknesses of both exercises. First, students generated absorbance data using an Excel spreadsheet, but they were overwhelmingly put off by simulated noise in their absorbance values. Second, students simulated running an HPLC using a Jupyter notebook and designed a method to separate three components of Excedrin. Students reported that the simulation helped them to understand HPLC and suggested that the online activity be used as a supplement when face-to-face laboratory instruction resumes. The main weakness of the online activities was that students did not perform any sample preparation. Therefore, they did not experience the extractions and dilutions required to prepare the analytical sample and had a difficult time working backward to calculate starting amounts from simulated sample concentrations. Concerns that students would extract answers from the equations used in the spreadsheet and Jupyter notebook were not realized.

The Chem Compute Science Gateway (chemcompute.org) is a free website where undergraduate chemistry students can easily setup a job, submit it to an XSEDE supercomputer, and visualize the output. Our website has several advantages over installing software packages locally. First, it is free to use and available anywhere on any device; it can be accessed by students off campus so that they can start a long job before class, leaving class time for data analysis. Second, jobs are run on XSEDE servers, enabling great computational power and long run times. Third, a web-interface is familiar to students, helping to put them more at ease with a difficult and feared subject. Fourth, several lab exercises are built into the website, eliminating the need for faculty to find or create computational labs. This free resource eliminates many barriers to computational chemistry such as cost of software, hardware, and faculty workload. This chapter describes the author's early attempts and failures at using free computational packages in class, the web-based science gateway that was built to enable graphically-based access to these packages, and the successes encountered after using the gateway in classes at a primarily undergraduate institution.

This publication describes a method for the quantification by high-performance liquid chromatography (HPLC) of resinous compounds known as α-acids found in freshly harvested, unprocessed hops. This method provides consistent, efficient, and accurate results as well as the theories and rationale involved in HPLC method development. A system of quality checks was utilized as well as the validation of numerous developmental variables. By starting with a theoretical approach in preparation, extraction, and instrumental techniques and then further developing these practices by experimentation, a reproducible method was developed. Following the validation, fresh cascade hops grown in Sonoma County were analyzed during the 2017 harvest season and found to be within the predicted range specific to this cultivar. This method encompasses the techniques necessary to analyze fresh or dried hops, considering variability between different laboratories.

In the experiment "How can you measure a reaction enthalpy without going into the lab?" we have students use computational thermochemistry to explore the properties and reaction thermodynamics of hydrofluoropropanes. This guided inquiry lab was developed under the Process Oriented Guided Inquiry Lab Physical Chemistry Laboratory (POGIL-PCL) project. Students are asked to find the "best" replacement for the hydrofluoropropane CFC-227ea, which has been used in military fire suppression systems. The compound has been known to decompose at high temperatures to produce poisonous HF, resulting in some casualties. Students are asked to choose an alternative compound based upon properties predicted with computational chemistry. The number of possibilities is large enough that a class will have to pool data to make a selection. As part of their study, students are also asked to evaluate calculational methods for speed and accuracy and to cooperatively choose the "best" method for the class's analysis. The evaluation of methods requires them to compare computational results with experimental values. Finally, students must use their calculational data to rationalize a choice about the "best" fire suppressant molecule.

A Web site is described that facilitates use of the free computational chemistry software: General Atomic and Molecular Electronic Structure System (GAMESS). Its goal is to provide an opportunity for undergraduate students to perform computational chemistry experiments without the need to purchase expensive software.

Aqueous hydroxyl radical (similar to 10(-12) M) oxidation of glycolaldehyde (1 mM), followed by droplet evaporation, forms secondary organic aerosol (SOA) that exhibits an effective liquid vapor pressure and enthalpy of vaporization of similar to 10(-7) atm and similar to 70 kJ/mol, respectively, similar to the mix of organic acids identified in reaction samples. Salts of these acids have vapor pressures about three orders of magnitude lower (e.g., ammonium succinate similar to 10(-11) atm), suggesting that the gas-particle partitioning behavior of glycolaldehyde SOA depends strongly on whether products are present in the atmosphere as acids or salts. Several reaction samples were used to simulate cloud droplet evaporation using a vibrating orifice aerosol generator. Samples were also analyzed by ion chromatography (IC), electrospray ionization mass spectrometry (ESI-MS), IC-ESI-MS, and for total carbon. Glycolaldehyde SOA mass yields were 50-120%, somewhat higher than yields reported previously (40-60%). Possible reasons are discussed: (1) formation of oligomers from droplet evaporation, (2) inclusion of unquantified products formed by aqueous photooxidation, (3) differences in gas-particle partitioning, and (4) water retention in dried particles. These and similar results help to explain the enrichment of organic acids in particulate organic matter above clouds compared with those found below clouds, as observed previously in aircraft campaigns.

Secondary organic aerosol (SOA) formation is enhanced on acidic seed particles; SOA also forms during cloud processing reactions where acidic sulfate is prevalent. Recently several studies have focused on the identification of organosulfates in atmospheric aerosols or smog chamber experiments, and upon the mechanism of formation for these products. We identify several organosulfate products formed during the laboratory OH radical oxidation of dilute aqueous glycolaldehyde in the presence of sulfuric acid. We propose a radical–radical reaction mechanism as being consistent with formation of these products under our experimental conditions. Using a kinetics model we estimate that organosulfates account for less than 1% of organic matter formed from these precursors during cloud processing. However, in wet acidic aerosols, where precursors are highly concentrated and acidic sulfate makes up close to half of the aerosol mass, this radical–radical reaction could account for significant organosulfate production.

There is a growing understanding that secondary organic aerosol (SOA) can form through reactions in atmospheric waters (i.e., clouds, fogs, and aerosol water). In clouds and wet aerosols, water-soluble organic products of gas-phase photochemistry dissolve into the aqueous phase where they can react further (e. g., with OH radicals) to form low volatility products that are largely retained in the particle phase. Organic acids, oligomers and other products form via radical and non-radical reactions, including hemiacetal formation during droplet evaporation, acid/base catalysis, and reaction of organics with other constituents (e.g., NH4+).This paper provides an overview of SOA formation through aqueous chemistry, including atmospheric evidence for this process and a review of radical and non-radical chemistry, using glyoxal as a model precursor. Previously unreported analyses and new kinetic modeling are reported herein to support the discussion of radical chemistry. Results suggest that reactions with OH radicals tend to be faster and form more SOA than non-radical reactions. In clouds these reactions yield organic acids, whereas in wet aerosols they yield large multifunctional humic-like substances formed via radical-radical reactions and their O/C ratios are near 1.

Introduction Conclusions References

Organic particulate matter (PM) formed in the atmosphere (secondary organic aerosol; SOA) is a substantial yet poorly understood contributor to atmospheric PM. Aqueous photooxidation in clouds, fogs and aerosols is a newly recognized SOA formation pathway. This study investigates the potential for aqueous glycolaldehyde oxidation to produce low volatility products that contribute SOA mass. To our knowledge, this is the first confirmation that aqueous oxidation of glycolaldehyde via the hydroxyl radical forms glyoxal and glycolic acid, as previously assumed. Subsequent reactions form formic acid, glyoxylic acid, and oxalic acid as expected. Unexpected products include malonic acid, succinic acid, and higher molecular weight compounds, including oligomers. Due to (1) the large source strength of glycolaldehyde from precursors such as isoprene and ethene, (2) its water solubility, and (3) the aqueous formation of low volatility products (organic acids and oligomers), we predict that aqueous photooxidation of glycolaldehyde and other aldehydes in cloud, fog, and aerosol water is an important source of SOA and that incorporation of this SOA formation pathway in chemical transport models will help explain the current under-prediction of organic PM concentrations.