Kinetics of the O plus O3 reaction

The gas phase reaction O + O3 yields 2 O2 was studied directly in a flow system under conditions of excess ozone, with O-atoms produced by thermal decomposition of Ar-O3 mixtures on a Nernst Glower, and measurement of the spatial O-atom decay by O + NO chemiluminescence with small, variable NO additions. The rate constant was found to be (9.6 + or - 0.7) x 10 to the minus 15th power cu/cm/molecule/sec at 298 K. Over the temperature range 269 to 409 K a rate expression (1.78 + or - 0.28) x 10 to the 11th power exp((-4.46 + or - 0.10 kcal/mole)/RT) is reported. The effects of interference by O2 (delta sub g) and product excitation are discussed, and the present results are compared with earlier investigations

Fundamental ignition study for material fire safety improvement, part 2

The autoignition behavior of polymeric compositions in oxidizing media was investigated as well as the nature and relative concentration of the volatiles produced during oxidative decomposition culminating in combustion. The materials investigated were Teflon, Fluorel KF-2140 raw gum and its compounded versions Refset and Ladicote, 45B3 intumenscent paint, and Ames isocyanurate foam. The majority of the tests were conducted using a stagnation burner arrangement which provided a laminar gas flow and allowed the sample block and gas temperatures to be varied independently. The oxidizing atmospheres were essentially air and oxygen, although in the case of the Fluorel family of materials, due to partial blockage of the gas inlet system, some tests were performed unintentionally in enriched air (not oxygen). The 45B3 paint was not amenable to sampling in a dynamic system, due to its highly intumescent nature. Consequently, selected experiments were conducted using a sealed tube technique both in air and oxygen media

From imagery to ecology: Leveraging time series of all available Landsat observations to map and monitor ecosystem state and dynamics

https://zslpublications.onlinelibrary.wiley.com/doi/full/10.1002/rse2.24Published versio

Develop and test fuel cell powered on-site integrated total energy systems: Phase 3, full-scale power plant development

A 25 cell stack of the 13 inch x 23 inch cell size (about 4kW) remains on test after 6000 hours, using simulated reformate fuel. A similar stack was previously shut down after 7000 hours on load. These tests were carried out for the purpose of assessing the durability of fuel cell stack components developed through the end of 1983. In light of the favorable results obtained, a 25kW stack that will contain 175 cells of the same size is being constructed using the same technology base. The components for the 25kW stack have been completed. A methanol steam reformer with a design output equivalent to 50kW has been constructed to serve as a hydrogen generator for the 25kW stack. This reformer and the balance of the fuel processing sub system are currently being tested and debugged. The stack technology development program focused on cost reduction in bipolar plates, nonmetallic cooling plates, and current collecting plates; more stable cathode catalyst support materials; more corrosion resistant metal hardware; and shutdown/start up tolerance

Develop and test fuel cell powered on-site integrated total energy systems

On-going testing of an 11 cell, 10.7 in. x 14 in. stack (about 1 kW) reached 2600 hours on steady load. Nonmetallic cooling plates and an automated electrolyte replenishment system continued to perform well. A 10 cell, 10.7 in. x 14 in. stack was constructed with a modified electrolyte matrix configuration for the purpose of reducing cell IR loss. The desired effect was achieved, but the general cell performance level was irregular. Evaluation is continuing. Preparations for a long term 25 cell, 13 in. x 23 in. test stack (about 4 kW) approached completion. Start up in early May 1984 is expected

Develop and test fuel cell powered on-site integrated total energy system

Test results are presented for a 24 cell, two sq ft (4kW) stack. This stack is a precursor to a 25kW stack that is a key milestone. Results are discussed in terms of cell performance, electrolyte management, thermal management, and reactant gas manifolding. The results obtained in preliminary testing of a 50kW methanol processing subsystem are discussed. Subcontracting activities involving application analysis for fuel cell on site integrated energy systems are updated

Recurrent violent injury: magnitude, risk factors, and opportunities for intervention from a statewide analysis.

INTRODUCTION: Although preventing recurrent violent injury is an important component of a public health approach to interpersonal violence and a common focus of violence intervention programs, the true incidence of recurrent violent injury is unknown. Prior studies have reported recurrence rates from 0.8% to 44%, and risk factors for recurrence are not well established. METHODS: We used a statewide, all-payer database to perform a retrospective cohort study of emergency department visits for injury due to interpersonal violence in Florida, following up patients injured in 2010 for recurrence through 2012. We assessed risk factors for recurrence with multivariable logistic regression and estimated time to recurrence with the Kaplan-Meier method. We tabulated hospital charges and costs for index and recurrent visits. RESULTS: Of 53 908 patients presenting for violent injury in 2010, 11.1% had a recurrent violent injury during the study period. Trauma centers treated 31.8%, including 55.9% of severe injuries. Among recurrers, 58.9% went to a different hospital for their second injury. Low income, homelessness, Medicaid or uninsurance, and black race were associated with increased odds of recurrence. Patients with visits for mental and behavioral health and unintentional injury also had increased odds of recurrence. Index injuries accounted for $105 million in costs, and recurrent injuries accounted for another$25.3 million. CONCLUSIONS: Recurrent violent injury is a common and costly phenomenon, and effective violence prevention programs are needed. Prevention must include the nontrauma centers where many patients seek care

Develop and test fuel cell powered on site integrated total energy sysems: Phase 3: Full-scale power plant development

A 25-cell stack of the 13 inch x 23 inch cell size (about 4kW) remains on test after 8300 hours, using simulated reformate fuel. A similar stack was previously shut down after 7000 hours on load. These tests have been carried out for the purpose of assessing the durability of fuel cell stack components developed through the end of 1983. A 25kW stack containing 175 cells of the same size and utilizing a technology base representative of the 25-cell stacks has been constructed and is undergoing initial testing. A third 4kW stack is being prepared, and this stack will incorporate several new technology features

Aerosol effect on the distribution of solar radiation over the clear-sky global oceans derived from four years of MODIS retrievals

International audienceA four year record of MODIS spaceborne data provides a new measurement tool to assess the aerosol direct radiative effect at the top of the atmosphere. MODIS derives the aerosol optical thickness and microphysical properties from the scattered sunlight at 0.55?2.1 ?m. The monthly MODIS data used here are accumulated measurements across a wide range of view and scattering angles and represent the aerosol's spectrally resolved angular properties. We use these data consistently to compute with estimated accuracy of ±0.3 Wm?2 the reflected sunlight by the aerosol over global oceans in cloud free conditions. The MODIS high spatial resolution (0.5 km) allows observation of the aerosol impact between clouds that can be missed by other sensors with larger footprints. We found that over the clear-sky global ocean the aerosol reflected 5.0±0.3Wm?2 with an average radiative efficiency of 46±2 Wm?2 per unit optical thickness. The seasonal and regional distribution of the aerosol radiative effects are discussed. The analysis adds a new measurement perspective to a climate change problem dominated so far by models

Cross Linking and Degradation Mechanisms in Model Sealant Candidates

Model compounds were investigated as to which type of heterocyclic ring is the most advantageous for curing sealants based on perfluoroalkylether chains. The relative thermal, thermal oxidative, hydrolytic, and fuel stability of potential crosslinks were determined. Specifically substituted materials were synthesized and evaluation of their stabilities in air, inert atmosphere, water, and Jet-A fuel at 235 and 325 C was made. Three heterocyclic ring systems were considered, namely, triazine, 1,2,4- and 1,3,4-oxadiazoles