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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

SU-G-TeP4-15: The Roucoulette: A Set of Quality Control Tests for Dynamic Trajectory (4Pi) Treatment Delivery Techniques

Purpose: To present and validate a set of quality control tests for trajectory treatment delivery using synchronized dynamic couch (translation and rotation), MLC and collimator motion. Methods: The quality control tests are based on the Picket fence test, which consist of 5 narrow band 2mm width spaced at 2.5cm intervals, and adds progressively synchronized dynamic motions. The tests were exposed on GafChromic EBT3 films. The first test is a regular (no motion and MLC static while beam is on) Picket Fence test used as baseline. The second test includes simultaneous collimator and couch rotation, each stripe corresponding to a different rotation speed. Errors in these tests were introduced (0.5 degree and 1 degree error in rotation synchronization) to assess the error sensitivity of this test. The second test is similar to the regular Picket Fence but now including dynamic MLC motion and couch translation (including acceleration during delivery) while the beam is on. Finally in the third test, which is a combination of the first and second test, the Picket Fence pattern is delivered using synchronized collimator and couch rotation and synchronized dynamic MLC and couch translation including acceleration. Films were analyzed with FilmQA Pro. Results: The distance between the peaks in the dose profile where measured (18.5cm away from the isocentre in the inplane direction where non synchronized rotation would have the largest effect) and compared to the regular Picket Fence tests. For well synchronized motions distances between peaks where between 24.9–25.4 mm identical to the regular Picket Fence test. This range increased to 24.4–26.4mm and 23.4–26.4mm for 0.5 degree and 1 degree error respectively. The amplitude also decreased up to 15% when errors are introduced. Conclusion: We demonstrated that the Roucoulette tests can be used as a quality control tests for trajectory treatment delivery using synchronized dynamic motion.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

A New Genomics-Driven Taxonomy of Bacteria and Archaea: Are We There Yet?

Taxonomy is often criticized for being too conservative and too slow and having limited relevance because it has not taken into consideration the latest methods and findings. Yet the cumulative work product of its practitioners underpins contemporary microbiology and serves as a principal means of shaping and referencing knowledge. Here, using methods drawn from the field of exploratory data analysis, this minireview examines the current state of the field as it transitions from a taxonomy based on 16S rRNA gene sequences to one based on whole-genome sequences and tests the validity of some commonly held beliefs.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

CRADA 376 Final Report Development of Protective Coatings for 1 kW Hot Zone

Pacific Northwest National Laboratory (PNNL) has extensive experience in the development, fabrication, and evaluation of surface treatments and protective coatings for metallic solid oxide fuel cell (SOFC) components. For example, modified (Mn,Co)3O4 spinel coatings and coating/metal interfaces have been shown to substantially improve oxidation resistance, electrical performance, and oxide scale adhesion of ferritic stainless steel interconnects in planar SOFC stacks. At the time of the establishment of this CRADA, Protonex Technology Corporation had been working in the field of SOFC development for over 12 years and had demonstrated more than 250 thermal cycles with a less than 15 minutes start time and more than 2000 hours of continuous operation on a 250W tubular solid oxide hot zone module as part of a program for the Office of the Secretary of Defense (OSD). An industrial version of the military system, denoted P200i, had been developed that was launched at the 2015 Fuel Cell Expo in Tokyo. Feedback during beta testing of this unit was very positive. However, Protonex recognized that to transition from military markets, the commercial system would require longer life time and higher power. Leveraging their novel thermal management strategy from the tubular hot zone that allowed for rapid and repeated thermal cycling, Protonex developed a planar 1kW module aimed at the industrial and commercial market. However, more robust interconnect coatings were needed to bring the system into the 1000+ hour life time requested by customers. Therefore, PNNL’s experience and technology were engaged to enable the 1kw system to transition from military applications to commercial and industrial applications. In this CRADA, PNNL teamed with Protonex to leverage PNNL’s expertise in protective coating techniques for solid oxide fuel cell (SOFC) applications. As the first step in the collaboration, protective spinel coatings were fabricated at PNNL onto ten AISI 440 stainless steel bus bars provided by Protonex. A precursor slurry containing spinel powder was applied to the steel surfaces via an ultrasonic spray process. The coated bars were then subjected to a reducing atmosphere heat treatment (i.e., heated to 850°C at 3°C/min in a hydrogen atmosphere and held at that temperature for five hours). Five of the bars were left in this reduced condition; the other five bars were subjected to an oxidizing heat treatment (i.e., heated to 1000°C at 3°C/min in air and held at that temperature for one hour). The bars were then sent to Protonex for testing. Subsequently, Protonex decided to discontinue their SOFC development activities, so they had no further interest in continuing the collaboration with PNNL, and the CRADA activities were terminated.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2012

Co-culture with Sertoli cells promotes proliferation and migration of umbilical cord mesenchymal stem cells

Highlights: Black-Right-Pointing-Pointer Co-culture of Sertoli cells (SCs) with human umbilical cord mesenchymal stem cells (UCMSCs). Black-Right-Pointing-Pointer Presence of SCs dramatically increased proliferation and migration of UCMSCs. Black-Right-Pointing-Pointer Presence of SCs stimulated expression of Mdm2, Akt, CDC2, Cyclin D, CXCR4, MAPKs. -- Abstract: Human umbilical cord mesenchymal stem cells (hUCMSCs) have been recently used in transplant therapy. The proliferation and migration of MSCs are the determinants of the efficiency of MSC transplant therapy. Sertoli cells are a kind of 'nurse' cells that support the development of sperm cells. Recent studies show that Sertoli cells promote proliferation of endothelial cells and neural stem cells in co-culture. We hypothesized that co-culture of UCMSCs with Sertoli cells may also promote proliferation and migration of UCMSCs. To examine this hypothesis, we isolated UCMSCs from human cords and Sertoli cells from mouse testes, and co-cultured them using a Transwell system. We found that UCMSCs exhibited strong proliferation ability and potential to differentiate to other cell lineages such as osteocytes and adipocytes. The presence of Sertoli cells in co-culture significantly enhanced the proliferation and migration potential of UCMSCs (P < 0.01). Moreover, these phenotypic changes were accompanied with upregulation of multiple genes involved in cell proliferation and migration including phospho-Akt, Mdm2, phospho-CDC2, Cyclin D1, Cyclin D3 as well as CXCR4, phospho-p44 MAPK and phospho-p38 MAPK. These findings indicate that Sertoli cells boost UCMSC proliferation and migration potential.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

Damage mechanisms in PBT-GF30 under thermo-mechanical cyclic loading

The scope of this paper is the investigation of damage mechanisms at microscopic scale on a short glass fiber reinforced polybutylene terephthalate (PBT-GF30) under thermo-mechanical cyclic loading. In addition the principal mechanisms are verified through micro mechanical FE models. In order to investigate the fatigue behavior of the material both isothermal strain controlled fatigue (ISCF) tests at three different temperatures and thermo-mechanical fatigue (TMF) tests were conducted on plain and notched specimens, manufactured by injection molding. The goal of the work is to determine the damage mechanisms occurring under TMF conditions and to compare them with the mechanisms occurring under ISCF. For this reason fracture surfaces of TMF and ISCF samples loaded at different temperature levels were analyzed using scanning electron microscopy. Furthermore, specimens that failed under TMF were examined on microsections revealing insight into both crack initiation and crack propagation. The findings of this investigation give valuable information about the main damage mechanisms of PBT-GF30 under TMF loading and serve as basis for the development of a TMF life estimation methodology.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Calibration of an ultra-low-background proportional counter for measuring {sup 37}Ar

An ultra-low-background proportional counter design has been developed at Pacific Northwest National Laboratory (PNNL) using clean materials, primarily electro-chemically-purified copper. This detector, along with an ultra-low-background counting system (ULBCS), was developed to complement a new shallow underground laboratory (30 meters water-equivalent) at PNNL. The ULBCS design includes passive neutron and gamma shielding, along with an active cosmic-veto system. This system provides a capability for making ultra-sensitive measurements to support applications like age-dating soil hydrocarbons with {sup 14}C/{sup 3}H, age-dating of groundwater with {sup 39}Ar, and soil-gas assay for {sup 37}Ar to support On-Site Inspection (OSI). On-Site Inspection is a key component of the verification regime for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Measurements of radionuclides created by an underground nuclear explosion are valuable signatures of a Treaty violation. For OSI, the 35-day half-life of {sup 37}Ar, produced from neutron interactions with calcium in soil, provides both high specific activity and sufficient time for inspection before decay limits sensitivity. This work describes the calibration techniques and analysis methods developed to enable quantitative measurements of {sup 37}Ar samples over a broad range of proportional counter operating pressures. These efforts, along with parallel work in progress on gas chemistry separation, are expected to provide a significant new capability for {sup 37}Ar soil gas background studies.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2015

Structural and functional screening in human induced-pluripotent stem cell-derived cardiomyocytes accurately identifies cardiotoxicity of multiple drug types

Safety pharmacology studies that evaluate new drug entities for potential cardiac liability remain a critical component of drug development. Current studies have shown that in vitro tests utilizing human induced pluripotent stem cell-derived cardiomyocytes (hiPS-CM) may be beneficial for preclinical risk evaluation. We recently demonstrated that an in vitro multi-parameter test panel assessing overall cardiac health and function could accurately reflect the associated clinical cardiotoxicity of 4 FDA-approved targeted oncology agents using hiPS-CM. The present studies expand upon this initial observation to assess whether this in vitro screen could detect cardiotoxicity across multiple drug classes with known clinical cardiac risks. Thus, 24 drugs were examined for their effect on both structural (viability, reactive oxygen species generation, lipid formation, troponin secretion) and functional (beating activity) endpoints in hiPS-CM. Using this screen, the cardiac-safe drugs showed no effects on any of the tests in our panel. However, 16 of 18 compounds with known clinical cardiac risk showed drug-induced changes in hiPS-CM by at least one method. Moreover, when taking into account the Cmax values, these 16 compounds could be further classified depending on whether the effects were structural, functional, or both. Overall, the most sensitive test assessed cardiac beating using the xCELLigence platform (88.9%) while the structural endpoints provided additional insight into the mechanism of cardiotoxicity for several drugs. These studies show that a multi-parameter approach examining both cardiac cell health and function in hiPS-CM provides a comprehensive and robust assessment that can aid in the determination of potential cardiac liability. - Highlights: • 24 drugs were tested for cardiac liability using an in vitro multi-parameter screen. • Changes in beating activity were the most sensitive in predicting cardiac risk. • Structural effects add in-depth insight towards mechanism of cardiac toxicity. • Testing functional and structural endpoints enhances early cardiac risk assessment.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Miniature High Temperature Testing Unit for HEPA Filter Materials R and D

The objective of this research is to develop and deploy advances in High Efficiency Particulate Air (HEPA) filter technology to benefit nuclear facilities. There is a need for better HEPA filter materials, especially those able to withstand moisture and higher temperatures as experienced in fire conditions. In order to test these materials, student teams at California Polytechnic State University (Cal Poly) have developed tools with the sponsorship and direction of Lawrence Livermore National Laboratory (LLNL). The Miniature High Temperature Testing Unit (MiniHTTU) can rapidly, efficiently and inexpensively test a large number of new and innovative materials for HEPA filter components. MiniHTTU test results will be used to down select the most promising materials for HEPA filter components (e.g., media, sealants, gaskets) for full scale testing in the full size High Temperature Testing Unit (HTTU). Using both testing units, future teams will be able to develop advances in HEPA filter technology (e.g., related to ceramic HEPA filters), the deployment of which will benefit DOE nuclear facilities by providing lower life-cycle costs and reducing or eliminating certain safety basis costs associated with safety class and safety significant systems in nuclear facilities. (authors)

36 MATERIALS SCIENCE↗
DOE OSTI2019

Emplacement Room Mock-up Structure for Testing the Placement of Nuclear Waste Within a Deep Geologic Repository - 19271

The Nuclear Waste Management Organization (NWMO) has conceptualized a unique method of long-term storage for spent nuclear waste. The concept encompasses all aspects of the end-of-life process from the point the spent fuel is no longer in-service; including handling, shipping, containing, storing, monitoring, and finally decommissioning. The equipment developed for each process is unique and designed specifically for each operation. Since these methods have not been implemented before, it is required to prove each process and the related equipment through simulations and eventually practical tests to evaluate performance and to confirm effective and safe operation. The spent fuel will be stored in an underground repository several hundred meters below the surface using autonomous machinery. Considering the significant investment and labour involved in creating full-scale tests underground, it would be impractical at this project stage to attempt tests of the newly developed machinery and methods in other than a surface setting. Therefore, our scope was to provide a customizable mock-up structure to simulate the conditions and constraints an underground repository would present. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2025

Greenhouse gas emissions reduction strategies that maximize portfolio-wide life cycle cost reduction, resilience, and environmental justice benefits

While strategies to achieve net-zero emissions at an individual site are well understood, new analysis methods are required for organizations seeking to achieve net-zero across multiple facilities, each with concurrent priority goals. At a portfolio level, distinct locations present varied challenges that cannot be addressed through singular solutions, and competing goals can take precedence with the assumption that net-zero emissions strategies deter from energy resilience and cost savings, therefore negatively impacting nearby communities. This study tests these assumptions by analyzing 16 diverse sites (varying in size, climate, and energy use) to identify strategies that reduce emissions and assess the impact these strategies have on life cycle costs, resilience, and communities with environmental justice concerns. Methods were developed to approximate missing information essential to net-zero evaluation. Established methods were augmented to evaluate life cycle costs, resilience, and environmental justice impacts across a set of strategies and accommodate the multi-criteria analyses. Potential benefits from identified strategies were quantified using site characteristics and a set of corresponding metrics. The net-zero analysis found that 11 sites could use on-site strategies to eliminate all but 2% of emissions generated. The remaining emissions can be offset, for instance through sequestration, executed at the portfolio scale. On-site carbon-free energy was found to reduce 51% of emissions across all sites; efficiency reduced 19% of emissions; sequestration 16%; procured carbon-free energy 15%; fuel switching 1.6%; and fleet electrification 1.3%. Building electrification, however, increased emissions by 4.4%. Different strategies also provide cost, resilience, and/or environmental justice benefits—the degree to which varies with individual site conditions. The findings indicate an advantage to considering the strategies as a comprehensive set, which leads to co-benefits, both in the ability to achieve net-zero goals and in advancing other goals. The results present the case for comprehensive advanced planning at the portfolio level to prioritize investments that will balance the minimization of emissions and life cycle cost with the maximization of resilience and environmental justice benefits. The novel methods for evaluation and integration, valuation of benefits, and consideration at the portfolio scale allow organizations to select investments that simultaneously address multiple key priorities.

Net-Zero Emissions↗
DOE OSTI2018

Effects of the Electron Beam Welding Process on the Microstructure, Tensile, Fatigue and Fracture Properties of Nickel Alloy Nimonic 80A

The purpose of this study was to evaluate rotary bending high-cycle fatigue properties and crack growth of Nimonic 80A-based metal and electron beam-welded joints. All the tests were performed at room temperature. Fracture surfaces under high-cycle fatigue and fatigue crack growth were observed by scanning electron microscopy. Microstructure, hardness and tensile properties were also evaluated in order to understand the effects on the fatigue results obtained. It was found that the tensile properties, hardness and high-cycle fatigue properties of the welded joint are lower than the base metal. The fracture surface of the high-cycle fatigue shows that fatigue crack initiated from the surface under the high stress amplitude and from the subsurface under the low stress amplitude. The effect of the welding process on the statistical fatigue data was studied with a special focus on probabilistic life prediction and probabilistic lifetime limits. The fatigue crack growth rate versus stress intensity factor range data were obtained from the fatigue crack growth tests. From the results, it was evident that the fatigue crack growth rates of the welded are higher than the base metal. The mechanisms and fracture modes of fatigue crack growth of welded specimens were found to be related to the stress intensity factor range ΔK. In addition, the effective fatigue crack propagation thresholds and mismatch of welded joints were described and discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Pathways to IEC Standards for Heliostat Design Qualification and Site Acceptance in Central Receiver CSP Applications

This paper surveys the existing landscape of standards relevant to heliostats, identifies their gaps, and proposes a path forward to a comprehensive set of heliostat guidelines, technical specifications, and standards under the framework of International Electrotechnical Commission (IEC) TC 117. Gaps in existing guidelines and standards are surveyed using a three-tiered taxonomy: component-level, heliostat-level, and field-level. At each level, the gap analysis is followed by a proposal for a coordinated path forward on the development of standards. At the component level, advances in the understanding of wind loading should inform a technical specification for drives and structures. Reflectors require consolidation of measurement guidelines into existing standards documents. Communications & controls require technical standards to inform their selection and secure implementation. At the heliostat level, IEC 62817 (solar trackers) adequately characterizes drive systems, structures, and electronics, but requires adaptation to heliostats' use patterns, operating modes, and expected life cycles. IEC 62817 does not address heliostat beam quality and pointing accuracy, but the process for determining both is elaborated in the SolarPACES Guideline for Heliostat Performance Testing. This SolarPACES document requires two main modifications: adaptation to IEC language and inclusion of testing after heliostats which have undergone accelerated weathering and mechanical cycling (to understand performance degradation). At the field level, IEC 62862-4-2 addresses the function and control of heliostat fields but does not cover the statistically rigorous testing of heliostat groups, or field performance factors like security and soiling. The addition of documents under IEC-62862-4 is proposed to address this gap.

beam↗
DOE OSTI2018

Ectopic Organogenesis after Allotransplantation of Freshly Removed or Cryopreserved Neonatal Testicle under the Renal Capsule in Rats

In experiments on white outbred male rats, a freshly removed (20 experiments) or cryopreserved (10 experiments) testicle from newborn rats (1-2 days after birth) was transplanted under the renal capsule after bilateral orchiectomy. In all experiments with transplantation of freshly removed testicle, it was engrafted. In 3 months, histological examination revealed the formation of mature seminiferous tubules, but spermatogenesis was blocked at the stage of spermatogonia; groups of proliferating Leydig cells in the loose connective tissue between the tubules were also seen. In 6 and 12 months, the status of the seminiferous tubules remained unchanged, but structures typical of the epididymis and developing vas deferens were revealed. The number of proliferating Leydig cells increased. The initially low testosterone concentration in the blood of castrated males increased significantly as soon as in 1 month after transplantation and grew up to 3 months, remaining at a level ~50% of normal. Engraftment of cryopreserved neonatal testicular tissue was observed in 60% cases, however, engrafted tissue, similar to the fresh one, retained the ability for organogenesis with the formation of mature seminiferous tubules, epididymis, and groups of proliferating Leydig cells. The dynamics of blood testosterone concentration in rats with cryopreserved and fresh transplantation was similar. Subcapsular transplantation did not adversely affect the kidneys, which was seen from normal histological structure of the kidneys and creatinine and urea concentrations in the blood.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

The nematode Caenorhabditis elegans survives subfreezing temperatures in an isochoric system

This study is the first experimental evidence showing that a living multicellular organism, the nematode Caenorhabditis elegans, can survive subfreezing temperatures in an isochoric (constant volume) thermodynamic system, while immersed in a simple isotonic solution, without the addition of cryoprotectants. Some of the test conditions were more extreme than those found at the ice/water interface of the Antarctic subglacial Vostok lake. On earth, life takes place in an isobaric (constant pressure) environment. In isobaric systems, subfreezing temperature survival of organisms in nature and subfreezing temperature preservation of living material for biotechnology and medicine, is made possible by use of cryoprotective chemicals additives. Our theoretical thermodynamic studies suggested that in an isochoric system, living biological material could survive subfreezing temperatures, without any cryoprotective chemicals. By confirming the theoretical predictions, this paper suggests a new technology for subfreezing preservation of cells, organs and organisms of possible value for biotechnology and medicine as well as new possible mechanisms of living organism survival in nature. - Highlights: • Preservation of biological materials at, subfreezing temperatures, in an isochoric system, is demonstrated. • Experiments were performed with Caenorhabditis elegans to pressures of 65 MPa and temperatures of −6 °C. • Isochoric subfreezing temperature is a new preservation method that does not require the use of cryoprotectants.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Novel localization of Aurora A kinase in mouse testis suggests multiple roles in spermatogenesis

Highlights: • Aurora A kinase is a previously identified mitotic kinase. • Developing male germ cells express Aurora A including spermatogonia, spermatocytes, and spermatids. • Aurora A kinase and its activated form are localized to the flagella of sperm. • Activated Aurora A kinase is enriched in motile sperm of the epididymis suggesting a role in sperm motility. Male germ cells are transformed from undifferentiated stem cells into spermatozoa through a series of highly regulated steps together termed spermatogenesis. Spermatogonial stem cells undergo mitosis and differentiation followed by two rounds of meiotic division and then proceed through a series of dramatic cell shape changes to form highly differentiated spermatozoa. Using indirect immunofluorescence, we investigated a role for the mitotic kinase, Aurora A (AURKA), in these events through localization of this protein in mouse testis and spermatozoa. AURKA is expressed in several cell types in the testis. Spermatogonia and spermatocytes express AURKA as expected based on the known role of this kinase in cell division. Surprisingly, we also found AURKA localized to spermatids and the flagellum of spermatozoa. Total AURKA and activated AURKA are expressed in different compartments of the sperm flagellum with total AURKA found in the principal piece and its phosphorylated and activated form found in the sperm midpiece. In addition, active AURKA is enriched in the flagellum of motile sperm isolated from cauda epididymis. These results provide evidence for a unique role for AURKA in spermatogenesis and sperm motility. Defining the signaling mechanisms that govern spermatogenesis and sperm cell function is crucial to understanding and treating male infertility as well as for development of new contraceptive strategies.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Ataxin-3 promotes testicular cancer cell proliferation by inhibiting anti-oncogene PTEN

Highlights: • Ataxin-3 is up-regulated in TC tissues. • Ataxin-3 promoted TC cell proliferation. • Ataxin-3 inhibited the expression of PTEN in TC cells. • Ataxin-3 indirectly activated the AKT/mTOR signaling pathway in TC cells. Human Ataxin-3 protein was first identified as a transcript from patients with Machado-Joseph disease (MJD), also known as spinocerebellar ataxia type 3 (SCA3). Recent studies have demonstrated that Ataxin-3 is involved in gastric cancer and lung cancer. However, the role of Ataxin-3 in testicular cancer (TC) remains poorly understood. This study aims to explore the significance of Ataxin-3 expression in TC. Firstly, we investigated 53 paired TC and para-tumor tissues and found that Ataxin-3 was overexpressed in TC tissues, and this overexpression of Ataxin-3 was correlated with tumor stages. Functionally, Ataxin-3 overexpression promoted cell proliferation, and Ataxin-3 knockdown inhibited cell proliferation. In addition, up-regulation of Ataxin-3 inhibited the expression of PTEN and activated the AKT/mTOR pathway. Conversely, inhibition of Ataxin-3 suppressed the expression of p-AKT and p-mTOR, and increased the expression of p-4EBP1. These findings may provide a better understanding about the mechanism of TC and suggest that Ataxin-3 may be a potential prognostic biomarker and therapeutic target for TC.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Red warning for air pollution in China: Exploring residents' perceptions of the first two red warnings in Beijing

Highlights: • We explore residents' perceptions of the first two red warnings issuance and its emergency measures in Beijing. • There is a significant different perception of the first two red warnings issuance. • People recommended that instead of reducing the number of red warnings, the red warning emergency measure should be adjusted. • Groups influenced by red warning gave less support its emergency measures. Air pollution early warnings have been issued in China to mitigate the effects of high pollution days. Public perceptions and views about early warning signals can affect individual behaviors and play a major role in the public's response to air pollution risks. This study examined public attitudes and responses to the first two red warnings for air pollution in Beijing in 2015. An online survey was sent out, and 664 respondents (response rate = 90%) provided their perspectives on the red warnings. Descriptive statistics, sign tests and binary logit models were used to analyze the data. More than half of the respondents reported that their life and work were affected by the red warning in December 2015. In contrast to their perceptions about the second red warning period, the public thought that the first red warning should have been issued earlier and that the number of consecutive days of warnings should have been reduced. The respondents also recommended that instead of reducing the number of red warnings, the red warning emergency measures should be adjusted. Specifically, the public preferred the installation of air purifiers in schools rather than closing schools and strengthening road flushing and dust pollution controls over restrictions on driving. Data analyses were conducted to examine the affected groups and different groups' perceptions of the necessity of implementing emergency measures. The results indicated that men and more educated respondents were more likely to be affected by driving limitations, and men were less supportive of these limitations. The age and education of respondents were significantly negatively associated with the opinion that schools should be closed, whereas wealthier respondents were more supportive of school closings. The finding of a negative attitude among the public toward the first two red warnings may be used to help local governments modify protective measures and pollution mitigation initiatives to increase acceptance.

54 ENVIRONMENTAL SCIENCES↗