Automatic, nondestructive test monitors in-process weld quality

Instrument automatically and nondestructively monitors the quality of welds produced in microresistance welding. It measures the infrared energy generated in the weld as the weld is made and compares this energy with maximum and minimum limits of infrared energy values previously correlated with acceptable weld-strength tolerances

Fractal analysis of fingerprints

Current methods for comparing fingerprints have weaknesses that have opened them to criticism. Current methods concentrate on the comparison of minutia in the print either manually or with the assistance of a computer algorithm. This causes these methods to depend highly on the presence of minutia and their relationship to one another. Absence or rotations of minutia can prevent current methods form making accurate comparisons. The goal of this process is to develop a new method for analyzing fingerprints that addresses many of the concerns with current methods.;The developed process uses an iterated function sequence (IFS) to convert the image of a fingerprint into a fractal pattern. The input for the IFS is constructed by a random walk through the image. Once a fingerprint is converted into a fractal pattern, the fractals can be used to make comparisons. Fractals are well defined mathematical objects that make them far easier to compare than fingerprints themselves. This process addresses many of the issues with current methods. This method is global in nature and thus it is not dependent on a set number of minutiae. Moreover, the rules for the random walk are constructed so as to make the fractal produced invariant of orientation of the print.;This method offers a new fast way to compare images. This method can be used to increase confidence, both in court and public opinion, in the use of fingerprints as identification. It can offer both an independent and/or supplemental method to the current ones used

Accretion from debris disks onto white dwarfs : Fingering (thermohaline) instability and derived accretion rates

Recent observations of a large number of DA and DB white dwarfs show evidence of debris disks, which are the remnants of old planetary systems. The infrared excess detected with \emph{Spitzer} and the lines of heavy elements observed in their atmospheres with high-resolution spectroscopy converge on the idea that planetary material accretes onto these stars. Accretion rates have been derived by several authors with the assumption of a steady state between accretion and gravitational settling. The results are unrealistically different for DA and DB white dwarfs. When heavy matter is accreted onto stars, it induces an inverse $\mu$-gradient that leads to fingering (thermohaline) convection. The aim of this letter is to study the impact of this specific process on the derived accretion rates in white dwarfs and on the difference between DA and DB. We solve the diffusion equation for the accreted heavy elements with a time-dependent method. The models we use have been obtained both with the IRAP code, which computes static models, and the La Plata code, which computes evolutionary sequences. Computations with pure gravitational settling are compared with computations that include fingering convection. The most important result is that fingering convection has very important effects on DAs but is inefficient in DBs. When only gravitational settling is taken into account, the time-dependent computations lead to a steady state, as postulated by previous authors. When fingering convection is added, this steady state occurs much later. The surprising difference found in the past for the accretion rates derived for DA and DB white dwarfs disappears. The derived accretion rates for DAs are increased when fingering convection is taken into account, whereas those for DBs are not modified. More precise and developed results will be given in a forthcoming paper

Design, manufacture, and test of infrared cross wire resistance micro-welding system Final report, 20 Jun. 1967 - 20 Mar. 1968

Design, equipment specifications, and operating characteristics for cross wire resistance microwelding syste

National Institute of Allergy and Infectious Diseases workshop report: "Chlamydia vaccines: The way forward".

Chlamydia trachomatis (Ct), an intracellular pathogen, is the most common bacterial sexually transmitted infection. In addition to acute cervicitis and urethritis, Ct can lead to serious sequelae of significant public health burden including pelvic inflammatory disease (PID) and infertility. Ct control efforts have not resulted in desired outcomes such as reduced incidence and reinfection, and this highlights the need for the development of an effective Ct vaccine. To this end, NIAID organized a workshop to consider the current status of Ct vaccine research and address critical questions in Ct vaccine design and clinical testing. Topics included the goal(s) of a vaccine and the feasibility of achieving these goals, animal models of infection including mouse and nonhuman primate (NHP) models, and correlates of protection to guide vaccine design. Decades of research have provided both whole cell-based and subunit vaccine candidates for development. At least one is currently in clinical development and efforts now need to be directed toward further development of the most attractive candidates. Overall, the discussions and presentations from the workshop highlighted optimism about the current status of Ct vaccine research and detailed the remaining gaps and questions needed to move vaccines forward

Barrier Lowering and Field Penetration at Metal-Dielectric Interfaces

We report here photoemission measurements on Si-SiO_2-Al structures in which the metal-SiO_2 barrier energy has been determined as a function of the electric field strength E in the dielectric. The expected barrier lowering is the sum of two terms: a) the Schottky term, proportional to E^(1/2) and b) a term due to the penetration of the electric field into the metal electrode, proportional to E. The experimental results are in good agreement with the model, where the Schottky effect involves the optical value of the dielectric constant of the oxide and the Thomas-Fermi screening distance in the metal is 1 Å. To our knowledge this represents the first unambiguous quantitative determination of either effect in a polar dielectric, although the Schottky effect alone has been observed in silicon

Clinical outcomes and risk factors for COVID-19 among migrant populations in high-income countries: a systematic review

Background: Migrants, including refugees, asylum seekers, labour migrants, and undocumented migrants, now constitute a considerable proportion of most high-income countries’ populations, including their skilled and unskilled workforces. Migrants may be at increased risk of COVID-19 due to their health and social circumstances, yet the extent to which they are being affected and their predisposing risk factors are not clearly understood. We did a systematic review to assess clinical outcomes of COVID-19 in migrant populations (cases, hospitalisations, deaths), indirect health and social impacts, and to determine key risk factors. / Methods: We did a systematic review following PRISMA guidelines, registered with PROSPERO (CRD42020222135). We searched databases including PubMed, Global Health, Scopus, CINAHL, and pre-print databases (medRxiv) via the WHO Global Research on COVID-19 database to Nov 18, 2020 for peer-reviewed and grey literature pertaining to migrants (defined as foreign born) and COVID-19 in 82 high-income countries. We used our international networks to source national datasets and grey literature. Data were extracted on our primary outcomes (cases, hospitalisations, deaths) and we evaluated secondary outcomes on indirect health and social impacts, and risk factors, using narrative synthesis. / Results: 3016 data sources were screened with 158 from 15 countries included in the analysis (35 data sources for primary outcomes: cases [21], hospitalisations [4]; deaths [15]; 123 for secondary outcomes). We found that migrants are at increased risk of infection and are disproportionately represented among COVID-19 cases. Available datasets suggest a similarly disproportionate representation of migrants in reported COVID-19 deaths, as well as increased all-cause mortality in migrants in some countries in 2020. Undocumented migrants, migrant health and care workers, and migrants housed in camps and labour compounds may have been especially affected. In general, migrants have higher levels of many risk factors and vulnerabilities relevant to COVID-19, including increased exposure to SARS-CoV-2 due to high-risk occupations and overcrowded accommodation, and barriers to health care including inadequate information, language barriers, and reduced entitlement to healthcare coverage related to their immigration status. / Conclusions: Migrants in high-income countries are at high risk of exposure to, and infection with, COVID-19. These data are of immediate relevance to national public health responses to the pandemic and should inform policymaking on strategies for reducing transmission of COVID-19 in this population. Robust data on testing uptake and clinical outcomes in migrants, and barriers and facilitators to COVID-19 vaccination, are urgently needed, alongside strengthening engagement with diverse migrant groups. / Competing Interest Statement: The authors have declared no competing interest. / Clinical Protocols: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD4202022213

Fixed base simulator study of an externally blown flap STOL transport airplane during approach and landing

A fixed-base simulator study was conducted to determine the flight characteristics of a representative STOL transport having a high wing and equipped with an external-flow jet flap in combination with four high-bypass-ratio fan-jet engines during the approach and landing. Real-time digital simulation techniques were used. The computer was programed with equations of motion for six degrees of freedom and the aerodynamic inputs were based on measured wind-tunnel data. A visual display of a STOL airport was provided for simulation of the flare and touchdown characteristics. The primary piloting task was an instrument approach to a breakout at a 200-ft ceiling with a visual landing

SWIRP (Submm-Wave and Long Wave InfraRed Polarimeter); Development and Characterization of a Sub-Mm Polarimeter for Ice Cloud Investigations

A major source of uncertainty in climate models is the presence, shape and distribution of ice particles in the uppermost layers of the clouds. The effects of this component are poorly constrained, turning ice particles into an almost-free variable in many climate models.NASA-GSFC is developing a new instrument aimed at measuring the size and shape of ice particles. The instrument consists of two sub-mm polarimeters (at 220 and 670 GHz) coupled with a long-wave infrared polarimeter at 10 micron. Each polarimeter has identical V-pol and H-pol channels; the axes of polarization are defined geometrically by the orientation of the waveguide elements, and the purity has been measured in the lab. The instrument is configured as a conical scanner, suitable for deployment as a payload on a small satellite or on a high-altitude sub-orbital platform. From a 400 km orbit, the instrument has a 3dB spatial resolution of 20 (10) km at 220 (670) GHz and a swath of 600 km over 180 degrees of view.The BAPTA (Bearing And Power Transfer Assembly) carries heritage from the SSMIS design, now in its 22nd year of on-orbit operation, but with a much reduced SWaP (Size Weight and Power) footprint, suitable for a small satellite.The main components of the instrument have been fabricated and are undergoing final testing prior to their integration as a single unit. The sub-mm channels have dedicated secondary reflectors which illuminate a shared primary reflector. The receiving units are placed behind the focal point of the optical arrangement, so that all beams equally illuminate the primary reflector and are almost co-located on the ground (within a single 220 GHz footprint). Primary and secondary beam patterns have been measured and verified to match the as-designed expectations. A Zytex (TM) window is deployed to protect the secondary reflectors and the feed horns from debris and other contaminants, and to reduce the heat load from the active (hot) IR calibration unit. The insertion loss of Zytex has been measured and is accounted in the calibration equation of the sub-mm channels.The radiometric performance of the sub-mm receivers has been characterized in the lab and under operational conditions of temperature and pressure.This paper discusses the design constraints on the sub-mm components, details of the scientific goals and their flowdown, and describes the characterization of the polarimeters. Options to optimize the layout and distribution of the masses within the assembly, with the goal of making the instrument even more compact and fully-compatible with cubesat-class satellites will be presented