A general low frequency acoustic radiation capability for NASTRAN

A new capability called NASHUA is described for calculating the radiated acoustic sound pressure field exterior to a harmonically-excited arbitrary submerged 3-D elastic structure. The surface fluid pressures and velocities are first calculated by coupling a NASTRAN finite element model of the structure with a discretized form of the Helmholtz surface integral equation for the exterior fluid. After the fluid impedance is calculated, most of the required matrix operations are performed using the general matrix manipulation package (DMAP) available in NASTRAN. Far field radiated pressures are then calculated from the surface solution using the Helmholtz exterior integral equation. Other output quantities include the maximum sound pressure levels in each of the three coordinate planes, the rms and average surface pressures and normal velocities, the total radiated power and the radiation efficiency. The overall approach is illustrated and validated using known analytic solutions for submerged spherical shells subjected to both uniform and nonuniform applied loads

The development of planned industrial districts in the Boston Metropolitan Area

Thesis (M.C.P.) Massachusetts Institute of Technology. Dept. of Architecture, 1954.Bibliography: leaf 46.by William F. Lipman.M.C.P

Wide-angle metamaterial absorber with highly insensitive absorption for TE and TM modes.

Being incident and polarization angle insensitive are crucial characteristics of metamaterial perfect absorbers due to the variety of incident signals. In the case of incident angles insensitivity, facing transverse electric (TE) and transverse magnetic (TM) waves affect the absorption ratio significantly. In this scientific report, a crescent shape resonator has been introduced that provides over 99% absorption ratio for all polarization angles, as well as 70% and 93% efficiencies for different incident angles up to [Formula: see text] for TE and TM polarized waves, respectively. Moreover, the insensitivity for TE and TM modes can be adjusted due to the semi-symmetric structure. By adjusting the structure parameters, the absorption ratio for TE and TM waves at [Formula: see text] has been increased to 83% and 97%, respectively. This structure has been designed to operate at 5 GHz spectrum to absorb undesired signals generated due to the growing adoption of Wi-Fi networks. Finally, the proposed absorber has been fabricated in a [Formula: see text] array structure on FR-4 substrate. Strong correlation between measurement and simulation results validates the design procedure

Descriptive account of 18 adults with known HIV infection hospitalised with SARS-CoV-2 infection

OBJECTIVE: To report on the clinical characteristics and outcome of 18 people living with HIV (PLWH) hospitalised with SARS-CoV-2 infection in a London teaching hospital. METHODS: The hospital notes of 18 PLWH hospitalised with SARS-CoV-2 infection were retrospectively reviewed alongside data concerning their HIV demographics from an established HIV Database. RESULTS: The majority (16/18) had positive PCR swabs for SARS-CoV-2, and two had negative swabs but typical COVID-19 imaging and history. Most were male (14/18, 78%), median age 63 years (range 47-77 years). Two-thirds were migrants, nine (50%) of Black, Asian and minority ethnicity (BAME). All were diagnosed with HIV for many years (range 8-31 years), and all had an undetectable HIV viral load (<40 copies/mL). The median CD4 prior to admission was 439 (IQR 239-651), and 10/16 (63%) had a CD4 nadir below 200 cells/mm3. Almost all (17/18) had been diagnosed with at least one comorbidity associated with SARS-CoV-2 prior to admission. 3/18 patients died. None received mechanical ventilation. Hospital stay and clinical course did not appear prolonged (median 9 days). CONCLUSIONS: Our data suggest that PLWH may not necessarily have prolonged or complex admissions to hospital when compared with the general hospital and national population admitted with COVID-19. Many had low nadir CD4 counts and potentially impaired functional immune restoration. The PLWH group was younger than generally reported for COVID-19, and the majority were male with multiple complex comorbidities. These patients had frequent contact with hospital settings increasing potential for nosocomial acquisition and increased risk of severe COVID-19

Extention of Finite Solvable Torsors over a Curve

Let $R$ be a discrete valuation ring with fraction field $K$ and with algebraically closed residue field of positive characteristic $p$. Let $X$ be a smooth fibered surface over $R$ with geometrically connected fibers endowed with a section $x\in X(R)$. Let $G$ be a finite solvable $K$-group scheme and assume that either $|G|=p^n$ or $G$ has a normal series of length 2. We prove that every quotient pointed $G$-torsor over the generic fiber $X_{\eta}$ of $X$ can be extended to a torsor over $X$ after eventually extending scalars and after eventually blowing up $X$ at a closed subscheme of its special fiber $X_s$.Comment: 16 page

Evidence of Rapid Phenocryst Growth of Olivine During Ascent in Basalts From the Big Pine Volcanic Field: Application of Olivine‐Melt Thermometry and Hygrometry at the Liquidus

The Quaternary Big Pine (BP) volcanic field in eastern California is notable for the occurrence of mantle xenoliths in several flows. This points to rapid ascent of basalt through the crust and precludes prolonged storage in a crustal reservoir. In this study, the hypothesis of phenocryst growth during ascent is tested for several basalts (13–7 wt% MgO) and shown to be viable. Phenocrysts of olivine and clinopyroxene frequently display diffusion‐limited growth textures, and clinopyroxene compositions are consistent with polybaric crystallization. When the most Mg‐rich olivine in each sample is paired with the whole‐rock composition, resulting Fe2+‐MgKD(olivine‐melt) values (0.31–0.36) match those calculated from literature models (0.32–0.36). Application of a Mg‐ and a Ni‐based olivine‐melt thermometer from the literature, both calibrated on the same experimental data set, leads to two sets of temperatures that vary linearly with whole‐rock MgO wt%. Because the Ni thermometer is independent of water content, it provides the actual temperature at the onset of olivine crystallization (1247–1097°C), whereas the Mg thermometer gives the temperature under anhydrous conditions and thus allows ΔT (=TMg − TNi = depression of liquidus due to water) to be obtained. The average ΔT for all samples is ~59°C, which is consistent with analyzed water contents of 1.5–3.0 wt% in olivine‐hosted melt inclusions from the literature. Because the application of olivine‐melt thermometry/hygrometry at the liquidus only requires microprobe analyses of olivine combined with whole‐rock compositions, it can be used to obtain large global data sets of the temperature and water contents of basalts from different tectonic settings.Plain Language SummaryBasaltic lavas are a window into their mantle source regions, which is why it is important to determine their temperatures and water contents. In this study, a new approach that allows these two parameters to be quantified is demonstrated for basalts from the Big Pine volcanic field, CA. They were targeted because many contain chunks of dense mantle rocks, which precludes storage in a crustal magma chamber and points to direct ascent from the mantle to the surface along fractures. Two hypotheses are proposed, tested, and shown to be viable in this study: (1) olivine crystallized in the basalts during ascent, and (2) the most Mg‐rich olivine analyzed in each basalt represents the first olivine to grow during ascent. This enables the most Mg‐rich olivine to be paired with the whole‐rock composition in the application of olivine‐melt thermometry and hygrometry. The results match those from published, independent studies. The success of this approach paves the way for the attainment of large, high‐quality data sets for basalts from a wide variety of tectonic settings. This, in turn, may allow global variations in mantle temperature and volatile content to be mapped in greater detail and better understood.Key PointsRapid phenocryst growth occurs during ascent in Mg‐rich basalts (some carry mantle xenoliths) from the Big Pine volcanic field, CAThe most Mg‐rich olivine can be paired with the whole‐rock composition to apply olivine‐melt thermometry/hygrometry at the liquidusLarge, high‐quality data sets on the temperature and water content of basalts from various tectonic settings can be obtained by this methodPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163434/3/ggge22329-sup-0001-2020GC009264-SI.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163434/2/ggge22329.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163434/1/ggge22329_am.pd

Mattia Damiani (1705–1776), poet and scientist in eighteenth century Tuscany

Mattia Damiani da Volterra (1705–1776), “renowned Doctor,” was the author in 1754 of a collection of scientifi c poems, Le Muse Fisiche (The Physical Muses) on two subjects: Newtonian physics and the plurality of the worlds. Damiani’s interest in science was precocious, but even at that, it was superimposed on his studies in jurisprudence completed in Pisa in 1726. In 2003, Damiani’s lost text, De Hygrometris et eorum defectibus disputatio (Disputation about hygrometers and their defects), which was printed in 1726 in Pisa, was brought to light. It characterizes him as a young scientist who refl ected upon the properties and limits of laboratory instruments and on nascent aspects of climatology. In this Disputation, a delightful amalgamation of scientifi c and humanistic literature is pursued. A discussion of the properties and limits of contemporary hygrometers and a comparison of the Cartesian and Newtonian hypotheses about cloud formations are interspersed with quotations of verses on natural phenomena, mostly from poems of the classic age—a prelude to the author’s future involvement in writing scientifi c verses. The poetry of Damiani, which often shows a musicality comparable to that of the poet Giacomo Leopardi (1798–1837), deserves to be recognized and saved from oblivion. Especially remarkable is the implicit “multimedia” project of a union among science, poetry, theater, and music. The rediscovered Disputation about hygrometers opens a new window on the personages involved and on the evolution of meteorological concepts in Europe in the context of the then-new Galilean and Newtonian physics