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In ARL Publications

Abstract

The Adirondack Chronology is intended to be a useful resource for researchers and others interested in the Adirondacks and Adirondack history.

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DigitalDocument

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In President's Report

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DigitalDocument

In President's Report

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2006-2016: A decade in review

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DigitalDocument

In President's Report

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DigitalDocument

In President's Report

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DigitalDocument

In President's Report

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DigitalDocument

In President's Report

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In President's Report

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In President's Report

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DigitalDocument

In Steinmetz Symposium

Abstract

Silica aerogels are excellent thermal and acoustic insulators with high porosity, very low density and low thermal conductivity. They are also highly translucent. These characteristics make aerogel a potential material for use in fenestration systems. The aerogels would conserve energy while transmitting natural light, and providing thermal and acoustic insulation. This talk will review methods for making aerogel-based windows.

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VideoObject

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In Steinmetz Symposium

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Aerogels are nanoporous materials that are comprised of 95 - 99% air. They have unique properties, such as being insulating materials, as well as having a high specific area and porosity. Silica aerogels can be used to make windows due to their translucent nature. In the aerogel lab at Union College, various projects have been conducted to characterize these properties and learn more about aerogels. One of these projects includes producing colored aerogels through the use of different colored dyes, which has been successful. These can then be used in producing windows with a stained glass effect. My work builds on those experiments by investigating the ability to produce aerogels that experience photochromic effects, which means the color of the aerogel would change based on exposure to different light intensities. This could be useful in a real-world application as no shades would be needed since the window would act as its own shade, darkening when the sunlight is over a certain intensity. Initial experiments focused on the use of photochromic dyes. Due to the high temperature and pressure required for processing that the aerogel must undergo, that approach has not been successful: the resulting materials were not translucent aerogels. Another approach under investigation is to use salts in an ion-exchange method to produce a photochromic effect. Using silver nitrate (AgNO3) in the precursor solution for the aerogel resulted in gels that showed no photochromic properties. The current approach is to synthesize silver chloride (AgCl) nanoparticles to use in the aerogel solution and characterize the results. This presentation will focus on the approaches and results taken to obtain photochromic aerogels.

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In Steinmetz Symposium

Abstract

Over one billion automobiles are in use around the world, the majority of which employ internal combustion engines. Catalytic converters are used to convert the toxic compounds found in car exhaust -- carbon monoxide, nitrogen oxides (NOx) and hydrocarbons -- to less harmful gases. The typical catalytic converter employs, as three-way catalysts, expensive raw materials such as platinum, palladium and/or rhodium. Aerogel materials have high surface area and thermal stability, properties that make them attractive for catalysis applications. Aerogels made with transition metal oxides (TMOs) are candidates to replace platinum in the catalytic converter. Chromium oxide (chromia) materials have demonstrated catalytic activity in other applications due to favorable redox chemistry, stability and selectivity. In this work, sol-gel synthesis techniques, using a 1:5 mole ratio of chromium(III) to aluminum, are adapted to a patented rapid supercritical extraction (RSCE) method to fabricate chromia-alumina catalytic aerogels. Physical characterization via several methods, including XRD and SEM, is performed on the chromia-alumina aerogels as prepared and following heat treatment. Catalytic performance of these promising materials is evaluated using an in-house-constructed testbed in which the aerogel materials are exposed to simulated automotive exhaust under temperature conditions that approximate those experienced in a catalytic converter. Initial tests demonstrate that chromia-alumina aerogels act as three-way catalysts.

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VideoObject

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In Steinmetz Symposium

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Aerogels have high porosity and specific surface area, as well as the ability to maintain textural stability at high temperatures, making them good heterogeneous catalysts. Catalytic performance can be enhanced by adding metal salts in the synthesis process. One application of great interest of catalytic aerogels is found in their potential to replace the environmentally unfriendly three-way-catalysts (TWCs) employed in automobile catalytic converters. Characterization can provide information about aerogels' microstructure (availability of catalyst sites), which can reveal ways to optimize catalytic efficiency. Alumina aerogels were synthesized by two different methods and with varying amounts of copper using the patented Union College rapid supercritical extraction (RCSE) method. These aerogels were then characterized using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Copper(0) microrods and microparticles were identified, as well as microcrystals containing copper and chlorine (the latter from the alumina aerogel precursor). The catalytic activity of aerogels prepared with different copper loading was assessed using the Union Catalytic Aerogel Testbed (UCAT).

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VideoObject

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In Steinmetz Symposium

Abstract

Virtually all cars on the road today use catalytic converters to reduce harmful emissions and comply with government regulations. Without catalytic converters these gases, like nitrous oxide and carbon monoxide, would deplete the ozone layer, contributing to climate change, or generate harmful smog. Most catalytic converters are made of two main components, a honeycomb corderite base and a washcoat saturated with platinum group metals (PGMs). The most crucial component of a catalytic converter is the platinum group metals within the washcoat as they catalyze the harmful gases released by the combustion process. The Union College aerogel lab has researched the possibility of replacing the PGM based washcoat used in catalytic converters with aerogels impregnated with less expensive, but still catalytically active, metals such as copper and cobalt. This seeks to take advantage of the properties of aerogels, such as high surface area and porosity, to augment the catalytic ability of these cheaper metals. The Union College aerogel lab has also attempted to theoretically model the catalytic ability of CoAl aerogels using the activation energy and kinetics of the reactions that occur during catalysis. My project started with attempts to synthesize an aerogel with PGM, but due to my inability to perform on campus experiments the focus of the project has shifted to modeling the catalytic performance of aerogels that have already been tested experimentally using a kinetic model in matlab. This poster will go over the experiments that I accomplished during my first term to synthesize PGM aerogels and the kinetic modeling that I am doing in my second term.

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DigitalDocument

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In Steinmetz Symposium

Abstract

Diesel engines release Diesel Particulate Matter (DPM). DPM is a pollutant composed of a complex mixture of very small particles of unburned fuel, lube oil, ash, sulfates, and water; and there are also traces of carcinogens such as benzene and formaldehyde. DPM poses significant risk to human health and the environment. Aerogels have unique properties (high surface area, low density, and low thermal conductivity) that make them potentially very well suited for the catalyzation and filtration of gas phase and particulate exhaust pollutants. In order to study the interaction between aerogels and DPM, a method of exposing the aerogels to DPM in a controllable way needed to be developed. To avoid the inconsistency and impracticality of using a real engine in the lab a DPM generator was developed to simulate the DPM exhaust of a diesel engine. Aerogels are placed in the simulated exhaust made by this generator, the soot DPM is captured and measured for aerogels of different chemical composition (Silica, etc.). This poster presents recent improvements made to the aerogel DPM filtration test bed and experimental methods used to quantify aerogel DPM filtration performance. Alongside these developments, due to the advent of coronavirus, a different direction for the project was taken after the campus was closed and access to the laboratory was no longer possible. Research was done to pinpoint typical vehicle specifications for both light and heavy-duty diesel engines in today market, as well as defining a Diesel Particulate Filter (DPF) model based upon thermal, fluid, mass, and momentum mechanics. This model was then used to designate important variables based upon the filter medium, and examine how these variables will function with the change from conventional DPM materials to Aerogels. This model helps to generate simulated outputs for proposed aerogel DPMs , and will work to help corroborate experimental data when we are able to get back into the lab.

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DigitalDocument

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In Steinmetz Symposium

Abstract

Silica aerogels are unique nanoporous materials that can be used in a variety of applications. Silica aerogels are attractive for window applications as they are monolithic, thermally insulating, and extremely lightweight. They also can be made transparent or translucent. Aerogels can be made using a variety of methods; in this work, a rapid supercritical extraction method (RSCE) is employed. Although typically translucent, silica aerogels can have dyes incorporated within them to create aerogels of a variety of colors. We are investigating the usage of dyed monolithic silica aerogels in window applications to improve aesthetic effects. However, the high temperatures and pressures required for the RSCE process can lead to dye degradation. In this presentation, we demonstrate how to incorporate Rhodamine 6B, Rhodamine B, and Fluorescein into monolithic silica aerogels. Rhodamine B experiences thermal degradation during monolithic aerogel synthesis. Adjusting processing parameters, including temperature and pressure, can minimize thermal degradation while ensuring the structural integrity of the aerogel. Ultraviolet radiation can also lead to dye degradation, which would be problematic for aerogels in a window application. Future work will focus on spectroscopic characterization of the dyed aerogel monoliths.

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DigitalDocument

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In Steinmetz Symposium

Abstract

Passenger vehicles with internal combustion engines are a major air pollution contributor due to their production of significant amounts of NOx, CO, and unburned hydrocarbons. Catalytic converters are used for automotive pollution mitigation. Aerogels are remarkable materials due to their highly porous nanostructure that is approximately 90-99% air by volume. Their high surface area and thermal stability make them attractive for catalytic applications. In this study, chromia-alumina aerogels were synthesized and characterized in order to evaluate their promise as catalysts for automotive applications. The sol-gel synthesis consisted of combining aluminum chloride hexahydrate, chromium(III) nitrate nonahydrate, ethanol (EtOH), and propylene oxide. The wet gels then underwent EtOH solvent exchanges over a series of days, and were processed by a rapid supercritical extraction method to yield aerogel samples. A heat-treatment process was then performed over 24 h at rising temperature increments to 800‚ÑÉ. The chromia-alumina aerogels were characterized through SEM and XRD, and will further be studied through the use of surface area measurements and IR spectroscopy. In preliminary work, these chromia-alumina aerogels were shown to catalyze the oxidation of CO and hydrocarbons and the reduction of NO.

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DigitalDocument

Rights Statement

In Steinmetz Symposium

Abstract

Internal combustion engines produce harmful exhaust gases. Catalytic converters are implemented to combat these harmful emissions. Located between the engine and exhaust, the catalytic converter speeds up the reactions that turn the gases leaving the engine into less harmful gases before they enter the atmosphere. To function properly, catalytic converters must reach a certain temperature, known as light-off temperature. Generally it takes two to three minutes for the modern catalytic converter to reach light-off temperature, during which about 70% of the harmful emissions produced are emitted into the atmosphere. To reduce the time to light-off temperature, I studied the thermal effects of using catalytically active aerogels in place of the traditional alumina washcoat used within the catalytic converter. Aerogels unique properties, notably low density and thermal stability, make it an ideal material for this application. I developed a finite-difference model of a flow channel in a catalytic converter and analyzed the thermal response of copper-alumina aerogel compared to alumina washcoat. Using copper-alumina aerogels in place of the alumina washcoat was found to significantly decrease the time to light-off temperature, and therefore reduce the amount of harmful emissions released into the atmosphere.

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DigitalDocument

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In Steinmetz Symposium

Abstract

The unique characteristics of silica aerogels allow them to be used in a wide variety of applications. They are extremely porous and have a low density, low thermal conductivity, large surface area and are relatively translucent. They can be used in a wide variety of applications such as in window systems, acoustic devices and in insulation. Making a large monolithic aerogel requires the use of a supercritical extraction process. At Union, we use the patented Rapid Supercritical Extraction (RSCE) method which uses a hydraulic hot press and confined metal mold, and have produced a 10 cm x 11 cm x 1.5 cm aerogel in a little over 10 hours. Various studies have been completed to understand what factors lead to the formation of cracks in the silica aerogel monoliths under some processing conditions. In this work, we statistically analyzed the factors that have the largest effect on the quality of the aerogel, i.e., the amount of cracking in each sample. The goal was to minimize cracking, thus maximize the quality. An initial screening design studied the effects of the heating rate, cooling rate, maximum temperature, sealing force, amount of grease, catalyst gel time, and force release rate, and found that the heating and cooling rates were the most important factors. A low heating rate and high cooling rate were found to best prevent crack formation. From this, a second screening was set up to look more closely at the cooling rate (how fast) and the length of the dwell time used at high temperature and pressure before the actual supercritical extraction step. In the end, we developed a set of parameters to produce a crack free aerogel that included a heating rate of 2 ¬?F/min, cooling rate of 30 ¬?F/min, and a dwell time of 60 min. Using these settings, it only takes a little over 6 hours in the hot press to produce an aerogel which is a 40% reduction in production time.

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DigitalDocument

Rights Statement

In Steinmetz Symposium

Abstract

Internal combustion engines utilize catalytic converters to combat the production of toxic compounds found in car exhaust, such as nitrogen oxides, carbon monoxide, and hydrocarbons, by converting them to more environmentally friendly gasses, such as carbon dioxide, water vapor, and nitrogen gas. Aerogels' high porosity and high surface area, as well as the ability to maintain textural stability at high temperatures, make them good candidates for heterogeneous catalysis applications. Past research in the Union College Aerogel Lab has shown that the catalytic performance of granular or powdered aerogels can be augmented by adding metal salts in the synthesis process. Unfortunately, free-standing granular aerogels would be an unaccommodating substitute for traditional catalytic converters as they are difficult to contain. While the low-difficulty, low-cost pathway into the commercialization of aerogel catalytic converters is through the introduction of aerogels into the conventional wash-coating process used to coat the catalytic converter substrate with a catalyst material, monolithic models may prove to be more feasible to produce and more effective at improving the catalysis of automotive emissions. Aerogels have high surface areas and are very porous, however, the rate of diffusion of gases through a monolithic aerogel is not suitable for use in a catalytic converter. The purpose of this research is to develop an aerogel catalytic converter prototype, and by doing so accomplish three things: 1) create multiple monolithic aerogel substrate models; 2) quantitatively compare the substrate models against each other to prescribe the most effective model; 3) and lastly, test the catalytic performance of the model when doped with catalytic metals. Five inert substrate models were created, and the model with the most reproducibility and mechanical stability under flow conditions was the laser cut two sides lined up model. This model was then doped with heat treated copper alumina aerogel granules and catalytically tested. While the catalytic testing showed that the first monolithic catalytic aerogel substrate iteration was inert when compared to previous union college granular catalytic aerogels, promising future iterations arose that could make monolithic catalytic converter substrates feasible.

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In Honors Theses

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Healthcare is a unique industry due to the high-level of governmental involvement and its importance to national economies and wellness. Policies that result in low reimbursement rates, low patient volumes, staffing shortages, and strict regulations have led many hospitals, primarily rural ones, to precipice of closure. Losing a hospital can be damaging for a community as it can greatly reduce access to care, worsen the quality of care, and increase healthcare costs overall. Many hospitals choose to affiliate with other provider organizations in order to avoid closure and/or improve their finances. While agreements can supply hospitals with additional resources, affiliation can also rob rural hospitals of their autonomy. This hinders hospitals' ability to address the needs of the communities that they serve. Additionally, health systems using hospital affiliation to expand into new markets exhibit, monopolistic behavior through horizontal integration. The effects of the affiliation trend have been studied more commonly from the hospital's perspective, as opposed to the patient's. Thus, this paper will investigate how hospital affiliation affects patient welfare. Patient welfare is defined along three axes, cost, access, and quality. A panel regression analysis was used to uncover the result of hospital affiliation on these three categories. The analysis showed that costs increase, access increased, and quality decreased.

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In Honors Theses

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One major reason for the evolutionary success of insects is their unique tracheal respiratory system. However, during development when oxygen demands are high, the tracheal system may not be able to deliver adequate oxygen to the tissues. In developing grasshoppers (Schistocerca americana), body mass can double during the intermolt period. Also during the intermolt period, jumping performance decreases while jumping muscle lactate production increases, suggesting oxygen delivery problems at the end of the instar. We hypothesize that decreased oxygen delivery during the instar is due to increasing body mass within the rigid exoskeleton compressing the air-filled tracheal system. To test this hypothesis, we identified female sixth instar S. americana. Similar to previous work, body mass increased 95% during the instar from 0.71g to 1.38g while femur length remained constant at 19.1mm. Using a Bruker SkyScan1272 micro-computed tomography (uCT) system, we scanned grasshoppers during the sixth instar (n=30). uCT image (TIF) files were reconstructed using NRecon and the tracheal system was segmented using Amira 3D and Biomedisa. Total body and tracheal volumes were analyzed using Amira 3D. Tracheal volume decreased by 82% during the instar; early instar tracheal volume was 0.29mL, while late instar tracheal volume was 0.06mL. While tracheal volume decreased, total body volume increased 97%. Therefore, the relative proportion of tracheal volume to body volume ratio decreased from 44.5% to 4.27% during the instar. Our findings that tracheal volumes decrease during the intermolt period support previous work showing that late stage grasshoppers rely more on anaerobic metabolism during repeated jumping.

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In Honors Theses

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The loss of heat through windows accounts for 25% of in-home heating and cooling losses. Due to climate change, conserving energy is more important than ever. If the interspace of windows was filled with silica-based aerogel, which has low thermal conductivity (0.012- 0.020 W/mK), it would result in significant energy savings. Monolithic silica-based aerogels have been previously synthesized using tetraethyl orthosilicate (TEOS) with transparency from 700-800 nm of 45%-73%. This presentation focuses on using a design-of-experiments approach to testing the conditions needed to produce monolithic TEOS-based aerogels with sufficient transparency for window applications by a patented rapid supercritical extraction (RSCE) method. Two designs of experiments (DOE) were carried out. The variables (1) quantity of time mixed in hydrolysis step, (2) quantity of time waiting in the hydrolysis step, (3) quantity of ethanol, (4) concentration of oxalic acid, (5) concentration of ammonia catalyst, and (6) quantity of water were tested to determine their effects on translucency and cracking of the resulting aerogel. The DOE results indicated that the concentration of ammonia catalyst and the quantity of time waiting in the hydrolysis step had the largest effect on the resulting aerogel's translucency.

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In Honors Theses

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Aerogels possess physical properties that make them interesting in research for better catalytic converters. They have a low density as well as a high surface area and porosity. Catalytic converters currently employ precious metals such as platinum, palladium, and rhodium to catalyze the oxidation of carbon monoxide (CO) and unburned hydrocarbons (HCs) and reduce nitrous oxides (NO_x). These precious metals are expensive and in low abundance in the earth's crust. Aerogels containing catalytic metals such as copper or nickel could be a cheaper alternative to the modern solution. Past work on copper-, nickel-, and cobalt-containing silica and alumina aerogels have shown promise for replacing current catalytic converters. The aerogels are fabricated using a sol-gel method and then ethanol excreted out using the rapid supercritical extraction (RSCE) method, patented by Union College. After fabrication, the aerogels underwent heat treatment to 800 ?C, above the highest temperature at which a catalytic convertor routinely performs. Through the use of powder x-ray diffraction (XRD) with thermal control, the aerogels were tested to determine their morphology before and after heat treatment as well as at elevated temperatures. The XRD patterns of the aerogels showed structural changes as heat treatment occurred. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were employed to show dispersion of impregnated metal as well as nano crystalline structures within the aerogel.

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In Honors Theses

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Over the past twenty years, marijuana has been the most widely accessible and widely used illicit drug in the United States of America. Marijuana is often labeled a gateway drug and is illegal to possess, use, or cultivate under federal law. However, movements of medical marijuana advocates see the drug as a potentially beneficial substance used to treat a variety of ailments including multiple sclerosis, Crohn’s Disease, and seizures. A strong push in support of legalizing marijuana for medicinal use has quickly gained nationwide traction. Since California first adopted medical marijuana legislation in 1996, twenty-eight states and Washington D.C. have passed similar medical marijuana legislation. Marijuana may be associated as a compliment or a substitute for other health related risky behaviors, leading to possible increases or decreases in tobacco use. The potential impact of long-term legalization of medical and recreational marijuana on greater cigarette co-use in adults is something that must be taken into account. This paper investigates the effect of medical marijuana legalization on individuals’ tobacco smoking participation, initiation, and cessation rates using the National Longitudinal Survey of Youth 1997 (NLSY97) data set from 1997 to 2015. The results I find indicate that those respondents living in states that legalized medical marijuana are associated with an increase in regular cigarette use and regular marijuana use. However, there is no evidence to show medical marijuana legalization had an effect on cigarette use initiation and cessation. These findings suggest potential negative effects of medical marijuana legalization on smoking outcomes. The negative implications of these effects are far reaching across the U.S. healthcare system.

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