Electropneumatic linear gimbal actuation system, model nv-bi, 29 june 1963 - 29 june 1964

Electropneumatic linear actuator for thrust vector control on J- 2 rocket engin

An instrument for measuring size-resolved aerosol hygroscopicity at both sub- and super-micron sizes

The article of record as published may be found at http://dx.doi.org/10.1080/02786820701506955A new instrument to measure the size-resolved hygroscopic growth of both sub- and super-micron atmospheric aerosol is described. It consists of two white-light optical particle counters measuring the same sample aerosol simultaneously at two different controlled relative humidities. Calibration with aerosols of different refractive index confirms the expected relative insensitivity of the instrument to index of refraction. Data obtained in the field from airborne sampling support the utility of the instrument in measuring differences in size-resolved hygroscopicity in the marine boundary layer and also in addressing the issue of kinetic limitations to aerosol condensational growth.Office of Naval ResearchGrant no. N0014-97-1-013

Material Availability: A Study of Academic Library Performance

This article reports the findings of a study modeled after Saracevic, Shaw, and Kantor\u27s efforts to identify and quantify the causes of users\u27 failures to identify and locate library materials. The researchers analyzed patron-reported and librarian-observed subject and known-item searches and found an overall success rate of only 54 percent. The problems that led to the 46 percent failure rate were analyzed by source and type of failure, and subjective observations concerning problems encountered by patrons were recorded. Recommendations are made for reducing library malfunctions and circulation, patron, and acquisition errors

Libro de Actas del I Congreso español de gestión integral de deyecciones ganaderas

Postprint (published version

Clear-column radiative closure during ACE-Asia: Comparison of multiwavelength extinction derived from particle size and composition with results from Sun photometry

From March to May 2001, aerosol size distributions and chemical compositions were measured using differential mobility analyzers (DMA), an aerodynamic particle sizer (APS), Micro-Orifice Uniform Deposit Impactors (MOUDI), and denuder samplers onboard the Twin Otter aircraft as part of the Aerosol Characterization Experiment (ACE)-Asia campaign. Of the 19 research flights, measurements on four flights that represented different aerosol characteristics are analyzed in detail. Clear-column radiative closure is studied by comparing aerosol extinctions predicted using in situ aerosol size distribution and chemical composition measurements to those derived from the 14-wavelength NASA Ames Airborne Tracking Sun photometer (AATS-14). In the boundary layer, pollution layers, and free troposphere with no significant mineral dust present, aerosol extinction closure was achieved within the estimated uncertainties over the full range of wavelengths of AATS-14. Aerosol extinctions predicted based on measured size distributions also reproduce the wavelength dependence derived from AATS-14 data. Considering all four flights, the best fit lines yield Predicted/Observed ratios in boundary and pollution layers of 0.97 ± 0.24 and 1.07 ± 0.08 at λ = 525 nm and 0.96 ± 0.21 and 1.08 ± 0.08 at λ = 1059 nm, respectively. In free troposphere dust layers, aerosol extinctions predicted from the measured size distributions were generally smaller than those derived from the AATS-14 data, with Predicted/Observed ratios of 0.65 ± 0.06 and 0.66 ± 0.05 at 525 and 1059 nm, respectively. A detailed analysis suggests that the discrepancy is likely a result of the lack of the knowledge of mineral dust shape as well as variations in aerosol extinction derived from AATS-14 data when viewing through horizontally inhomogeneous layers

In situ aerosol-size distributions and clear-column radiative closure during ACE-2

As part of the second Aerosol Characterization Experiment (ACE-2) during June and July of 1997, aerosol-size distributions were measured on board the CIRPAS Pelican aircraft through the use of a DMA and 2 OPCs. During the campaign, the boundary-layer aerosol typically possessed characteristics representative of a background marine aerosol or a continentally influenced aerosol, while the free-tropospheric aerosol was characterized by the presence or absence of a Saharan dust layer. A range of radiative closure comparisons were made using the data obtained during vertical profiles flown on 4 missions. Of particular interest here are the comparisons made between the optical properties as determined through the use of measured aerosol-size distributions and those measured directly by an airborne 14-wavelength sunphotometer and 3 nephelometers. Variations in the relative humidity associated with each of the direct measurements required consideration of the hygroscopic properties of the aerosol for size-distribution-based calculations. Simultaneous comparison with such a wide range of directly-measured optical parameters not only offers evidence of the validity of the physicochemical description of the aerosol when closure is achieved, but also provides insight into potential sources of error when some or all of the comparisons result in disagreement. Agreement between the derived and directly-measured optical properties varied for different measurements and for different cases. Averaged over the 4 case studies, the derived extinction coefficient at 525 nm exceeded that measured by the sunphotometer by 2.5% in the clean boundary layer, but underestimated measurements by 13% during pollution events. For measurements within the free troposphere, the mean derived extinction coefficient was 3.3% and 17% less than that measured by the sunphotometer during dusty and non-dusty conditions, respectively. Likewise, averaged discrepancies between the derived and measured scattering coefficient were −9.6%, +4.7%, +17%, and −41% for measurements within the clean boundary layer, polluted boundary layer, free troposphere with a dust layer, and free troposphere without a dust layer, respectively. Each of these quantities, as well as the majority of the >100 individual comparisons from which they were averaged, were within estimated uncertainties

Airborne sunphotometer, airborne in-situ, space-borne, and ground-based measurements of tropospheric aerosol in ACE-2

The North Atlantic Regional Aerosol Characterization Experiment (ACE-2) of the International Global Atmospheric Chemistry Project (IGAC) ran from 16 June to 25 July 1997. The results presented in this study are part of the "Clear-sky column closure experiment" (CLEARCOLUMN) activity, one of 6 ACE-2 activities [1]. Clear-sky column closure experiments call for characterization of aerosol layers by simultaneous measurements using different techniques that can be related using models [2]. A wide range of aerosol types was encountered throughout the ACE-2 area, including background Atlantic marine, European pollution-derived and African mineral dust. In a series of papers, we reported on ACE-2 CLEARCOLUMN results obtained by combining airborne sunphotometer and in-situ measurements taken aboard the Pelican aircraft, spaceborne NOAA/VHRR data and ground-based lidar and sunphotometer measurements [3]-[10]. Those and other CLEARCOLUMN results have been summarized in [11]. In this paper we only report on results not shown in this form in [3]-[11]

Impacts of Remote Physical Exercises on Functional Status and Mobility among Community-Dwelling Pre-Disabled Seniors during the Covid-19 Lockdown

peer reviewedObjectives: To assess whether remote physical exercise interventions helped maintain function in daily life, level of physical activities, basic mobility and frailty status in pre-disabled seniors during the first Covid-19 lockdown. Design: This is an interventional study conducted from May 2020 to May 2021. Setting: Community-dwelling older adults in 2 Canadian cities. Participants: 84 pre-disabled seniors. Intervention: 12-week physical exercise programs (1 hour/ 3 times/ week) in kinesiologist-guided groups using Zoom or phone-supervised individual booklet-based home-program (n=44) vs. Control (usual life habits; n=40). Measurements: Functional status in daily activities (OARS scale); Daily level of aerobic (TAPA-1) and strengthening/flexibility (TAPA-2) physical activities; Basic mobility abilities (SPPB: balance, lower limbs strength, walking speed; Timed Up-and-Go) and Frailty (SOF index) were assessed at baseline and at 3, 6, 9 and 12-month follow-ups. Results: The participants’ mean age was 78.5 ± 7.2 and 76.5 % were women. There was a group * time effect for the OARS scale (p=0.02), the TAPA-1 (p=0.06) and the TAPA-2 (p=0.007) scores. For these outcomes, scores significantly improved during the first 3 months of follow-up and then stabilised in the intervention group whereas they remained constant in the control group over time. There was an overall time effect for the SPPB (p=0.004), the 4-m walking speed (p=0.02) and for the SOF index (p=0.004), with no between-group differences. Finally, no effect was observed for the TUG. Conclusion: Remote home-based physical exercise interventions and monitoring during the first Covid-19 lockdown seemed to have helped maintain seniors’ level of physical activities without impacting on basic mobility abilities. Further studies are needed to identify parameters of remote exercise programs that can improve daily function and mobility in this population