Sandia capabilities for the measurement, characterization, and analysis of heliostats for CSP.

The Concentrating Solar Technologies Organization at Sandia National Laboratories has a long history of performing important research, development, and testing that has enabled the Concentrating Solar Power Industry to deploy full-scale power plants. Sandia continues to pursue innovative CSP concepts with the goal of reducing the cost of CSP while improving efficiency and performance. In this pursuit, Sandia has developed many tools for the analysis of CSP performance. The following capabilities document highlights Sandia's extensive experience in the design, construction, and utilization of large-scale testing facilities for CSP and the tools that Sandia has created for the full characterization of heliostats. Sandia has extensive experience in using these tools to evaluate the performance of novel heliostat designs

Building capacity for collaborative research between basic scientists and underrepresented communities in cancer research

Purpose: Basic science research is critical for understanding biological mechanisms essential to advances in cancer prevention, diagnoses and treatment. However, most of this research is conducted outside of the purview of community observation or input, leaving these research processes mysterious and subsequent findings disconnected from the communities they intend to benefit. This paper discusses strategies to build capacity for collaborations between basic scientists and Hispanic community members at the University of Arizona Cancer Center (UACC). Methods: Through partnership of the Cancer Biology Program and Office of Community Outreach and Engagement both at UACC, the Research Outreach for Southern Arizona (ROSA) program was developed as a way to forward the following strategies to build capacity for collaboration: forming a community working group, launching a community and student ambassador program, hosting scientific cafés and developing a community-based survey. Results: The strategies underpinning the ROSA program have been integral in bridging dialogue between basic scientists and the community and fostering bidirectional learning opportunities. Each of the strategies presented have documented successes and based on the lessons learned, they have evolved into productive and integral parts of UACC’s overall strategy of bridging scientific research and communities. Conclusion: While the strategies discussed are evolving, they help foster dialogue and exchange between basic scientists and community members that demystifies basic science research and facilitates culturally tailored approaches to address health disparities of vulnerable communities. These strategies also have the potential to shift cancer research into a paradigm that is more collaborative and transformative.12 month embargo; first published 03 June 2023This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Uranyl acetate induced DNA single strand breaks and AP sites in Chinese hamster ovary cells

The aim of this study is to characterize the genotoxicity of depleted uranium (DU) in Chinese Hamster Ovary cells (CHO) with mutations in various DNA repair pathways. CHO cells were exposed to 0-300 mu M of soluble DU as uranyl acetate (UA) for 0-48 h. Intracellular UA concentrations were measured via inductively coupled mass spectrometry (ICP-MS) and visualized by transmission electron microscopy (TEM). Cytotoxicity was assessed in vitro by clonogenic survival assay. DNA damage response was assessed via Fast Micromethod (R) to determine UA-induced DNA single strand breaks. Results indicate that UA is entering the CHO cells, with the highest concentration localizing in the nucleus. Clonogenic assays show that UA is cytotoxic in each cell line with the greatest cytotoxicity in the base excision repair deficient EM9 cells and the nuclear excision repair deficient UV5 cells compared to the non-homologous end joining deficient V3.3 cells and the parental AA8 cells after 48 h. This indicates that UA is producing single strand breaks and forming UA DNA adducts rather than double strand breaks in CHO cells. Fast Micromethod (R) results indicate an increased amount of single strand breaks in the EM9 cells after 48 h UA exposure compared to the V3.3 and AA8 cells. These results indicate that DU induces DNA damage via strand breaks and uranium-DNA adducts in treated cells. These results suggest that: (1) DU is genotoxic in CHO cells, and (2) DU is inducing single strand breaks rather than double strand breaks in vitro.National Institutes of Health [CA096281, CA096320, ES019703, F31ES014971]; Partnership for Native American Cancer Prevention [U54CA143924]; Southwest Environmental Health Sciences Centers [P30ES006694]; Alfred P. Sloan Foundation; More Graduate Education at Mountain States Alliance12 month embargo; published online: 24 April 2018This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Final Report Comparative Health Services Evaluation Project Navajo Health Authority 1967-1977

The Comparative Health Services Evaluation Project (CHSEP) Phase 3 was conducted by the Navajo Health Authority, Division of Health Statistics and Research, for the Navajo Area Indian Health Service (IHS) from July 1976 through June 30, 1977. Through this project and two preceding projects, valuable knowledge regarding health care providers and consumers all over the Reservation of various socioeconomic and cultural levels was obtained. The purpose and goals of the CHSEP was to provide baseline information on health care needs and priorities for the Navajo IHS and to insure better planning and evaluation of its health program in the future. The provider survey instrument was a self-administered questionnaire that utilized yes/no answers. It was designed to solicit attitudes regarding satisfaction with four specific areas and one profile category: 1) Profile category; 2) Quality of Financing; 3) Administration of the Facility; 4) Satisfaction with Financing; and 5) Professional Satisfaction. Information obtained from the consumer survey was done by personal interview on a target population of 79 households that were randomly selected. Several tables and narratives were used to describe the data.The Provider Survey revealed that non-Indian professionals most often held top positions for longer time spans than equally qualified Indian health professionals. Kayenta reported the lowest level of satisfaction in quality care: over 50% of the workers were dissatisfied with the administration. The Gallup area showed the highest level of professional satisfaction with a direct correlation to working in a modern facility. The consumer survey (interview) revealed that transportation, communication, water and waste disposal facilities contributed to limited use of IHS factilities and in some cases, generated health problems.The authors concluded that the providers feel they are a part of a high quality organization that is drastically under funded and under staffed. Funds should by increased to improve facilities and increase staffing at IHS units. Increases in funds, personnel, and facilities should be actively sought from other funding sources, i.e., agreements with universities, special funding sources, etc. There were no specific recommendations for the consumer situation except that Navajo speaking people should continually be used when conducting such surveys

Characterization of Particle Flow in a Free-Falling Solar Particle Receiver

Falling particle receivers are being evaluated as an alternative to conventional fluid-based solar receivers to enable higher temperatures and higher efficiency power cycles with direct storage for concentrating solar power (CSP) applications. This paper presents studies of the particle mass flow rate, velocity, particle-curtain opacity and density, and other characteristics of free-falling ceramic particles as a function of different discharge slot apertures. The methods to characterize the particle flow are described, and results are compared to theoretical and numerical models for unheated conditions. Results showed that the particle velocities within the first 2 m of release closely match predictions of free-falling particles without drag due to the significant amount of air entrained within the particle curtain, which reduced drag. The measured particle-curtain thickness (∼2 cm) was greater than numerical simulations, likely due to additional convective air currents or particle–particle interactions neglected in the model. The measured and predicted particle volume fraction in the curtain decreased rapidly from a theoretical value of 60% at the release point to less than 10% within 0.5 m of drop distance. Measured particle-curtain opacities (0.5–1) using a new photographic method that can capture the entire particle curtain were shown to match well with discrete measurements from a conventional lux meter

COUPLED OPTICAL-THERMAL-FLUID MODELING OF A DIRECTLY HEATED TUBULAR SOLAR RECEIVER FOR SUPERCRITICAL CO2 BRAYTON CYCLE

Recent studies have evaluated closed-loop supercritical carbon dioxide (s-CO2) Brayton cycles to be a higher energy density system in comparison to conventional superheated steam Rankine systems. At turbine inlet conditions of 923K and 25 MPa, high thermal efficiency (similar to 50%) can be achieved. Achieving these high efficiencies will make concentrating solar power (CSP) technologies a competitive alternative to current power generation methods. To incorporate a s-CO2 Brayton power cycle in a solar power tower system, the development of a solar receiver capable of providing an outlet temperature of 923 K (at 25 MPa) is necessary. The s-CO2 will need to increase in temperature by similar to 200 K as it passes through the solar receiver to satisfy the temperature requirements of a s-CO2 Brayton cycle with recuperation and recompression. In this study, an optical-thermal-fluid model was developed to design and evaluate a tubular receiver that will receive a heat input similar to 2 MWth from a heliostat field. The ray-tracing tool SolTrace was used to obtain the heat-flux distribution on the surfaces of the receiver. Computational fluid dynamics (CFD) modeling using the Discrete Ordinates (DO) radiation model was used to predict the temperature distribution and the resulting receiver efficiency. The effect of flow parameters, receiver geometry and radiation absorption by s-CO2 were studied. The receiver surface temperatures were found to be within the safe operational limit while exhibiting a receiver efficiency of similar to 85%

Contribution of reactive oxygen species to the pathogenesis of pulmonary arterial hypertension.

Pulmonary arterial hypertension is associated with a decreased antioxidant capacity. However, neither the contribution of reactive oxygen species to pulmonary vasoconstrictor sensitivity, nor the therapeutic efficacy of antioxidant strategies in this setting are known. We hypothesized that reactive oxygen species play a central role in mediating both vasoconstrictor and arterial remodeling components of severe pulmonary arterial hypertension. We examined the effect of the chemical antioxidant, TEMPOL, on right ventricular systolic pressure, vascular remodeling, and enhanced vasoconstrictor reactivity in both chronic hypoxia and hypoxia/SU5416 rat models of pulmonary hypertension. SU5416 is a vascular endothelial growth factor receptor antagonist and the combination of chronic hypoxia/SU5416 produces a model of severe pulmonary arterial hypertension with vascular plexiform lesions/fibrosis that is not present with chronic hypoxia alone. The major findings from this study are: 1) compared to hypoxia alone, hypoxia/SU5416 exposure caused more severe pulmonary hypertension, right ventricular hypertrophy, adventitial lesion formation, and greater vasoconstrictor sensitivity through a superoxide and Rho kinase-dependent Ca2+ sensitization mechanism. 2) Chronic hypoxia increased medial muscularization and superoxide levels, however there was no effect of SU5416 to augment these responses. 3) Treatment with TEMPOL decreased right ventricular systolic pressure in both hypoxia and hypoxia/SU5416 groups. 4) This effect of TEMPOL was associated with normalization of vasoconstrictor responses, but not arterial remodeling. Rather, medial hypertrophy and adventitial fibrotic lesion formation were more pronounced following chronic TEMPOL treatment in hypoxia/SU5416 rats. Our findings support a major role for reactive oxygen species in mediating enhanced vasoconstrictor reactivity and pulmonary hypertension in both chronic hypoxia and hypoxia/SU5416 rat models, despite a paradoxical effect of antioxidant therapy to exacerbate arterial remodeling in animals with severe pulmonary arterial hypertension in the hypoxia/SU5416 model

On-sun testing of an advanced falling particle receiver system

A 1 MWth high-temperature falling particle receiver was constructed and tested at the National Solar Thermal Test Facility at Sandia National Laboratories. The continuously recirculating system included a particle elevator, top and bottom hoppers, and a cavity receiver that comprised a staggered array of porous chevron-shaped mesh structures that slowed the particle flow through the concentrated solar flux. Initial tests were performed with a peak irradiance of ~300 kW/m2 and a particle mass flow rate of 3.3 kg/s. Peak particle temperatures reached over 700 °C near the center of the receiver, but the particle temperature increase near the sides was lower due to a non-uniform irradiance distribution. At a particle inlet temperature of ~440 °C, the particle temperature increase was 27 °C per meter of drop length, and the thermal efficiency was ~60% for an average irradiance of 110 kW/m2 . At an average irradiance of 211 kW/m2 , the particle temperature increase was 57.1 °C per meter of drop length, and the thermal efficiency was ~65%. Tests with higher irradiances are being performed and are expected to yield greater particle temperature increases and efficiencies