Explore the vast range of titles available.

As wireless network devices and IOT connectivity develop, the application and demand for small, low power, in situ sensors and instruments will expand. There are continuous efforts in the miniaturization of sensors and scientific instrument systems for conventional to field deployable and rugged hand held units for personal use to extreme harsh environment applications. This work investigates mesoscale cylindrical ion trap (CIT) mass analyzer design and the benefits of CITs realized via additive manufactured metalized ceramic material systems for improved ion signal, low power performance, and extended dynamic range. Rugged monolithic miniature mass spectrometer ceramic CIT chips have been produced that have increased signal output with reduced power consumption. We have demonstrated via simulation and experiment ~80% and greater CIT ion detection efficiency, signal improvement of the percentage of analyzed ions detected, from 50% detection for conventional CIT designs. Utilizing a unique notched ring electrode design that increases the ion signal output to the detector, the electron ionization quantity and power required for mass spectrum generation and tuning was reduced by ~1 watt or 33%, as well as the required gain of the ion detector. Increased CIT ion detection efficiency effectively increases the total amount of the sample analyzed versus what is lost, thus increasing the instrument sensitivity and data collected, reducing duty cycle and power. Identical CITs of a ring electrode radius, ro = 1 mm, were fabricated from low temperature co-fired ceramic (LTCC) and the stainless steel (SS) for performance comparison and were tested in mass instability scanning and resonance ejection modes to produce Perfluorotribuytlamine (PFTBA) mass spectra. The ceramic material system offers design anFd material benefits which reduce the CIT power consumption by 29x from ~10.20 mW power consumption of the stainless steel CIT design to 0.36 mW for the ceramic CIT, as well as enabling batch fabrication, reduced cost and manufacturing defects. While the stated design and material system benefits may facilitate CIT and MS system miniaturization, and the production of the ceramic CIT chip, the proof of concept of CIT ion ejection efficiency via the notched ring electrode may enhance ion trap designs at any scale.

An ion source may include first, second, and third electrodes. The first electrode may be a repeller having a V-shaped groove. The second electrode may be an electron emitter filament disposed adjacent the base of the V-shaped groove. The third electrode may be an anode that defines an enclosed volume with an aperture formed therein adjacent the electron emitter filament. A potential of the first electrode may be less than a potential of the second electrode, and the potential of the second electrode may be less than a potential of the third electrode. A fourth electrode that is disposed between the electron emitter filament and the anode may be used to produce a more collimated electron beam.

Comets are currently believed to be a mixture of interstellar and nebular material. Many of the volatiles in comets are attributed to interstellar chemistry, because the same species of carbonaceous compounds are also observed in ices in interstellar molecular (ISM) clouds. Comets are thus likely to be a relatively pristine reservoir of primitive material and carbonaceous compounds in our solar system. They could be a major contributor to the delivery of prebiotic organic compounds, from which life emerged through impacts on early Earth. Mass spectrometers are very powerful tools to identify unknown chemicals, and much progress bas been made in miniaturizing mas spectrometers for space applications. Most miniatu rized mass spectrometers developed to date, however, are still relatively large, power hungry, complicated to assemble, and would have significant impact on space flight vehicle total payload and resource allocations.

Traditional mirrors at optical wavelengths use thin metalized or dielectric layers of uniform thickness to approximate a perfect electric field boundary condition. The electron gas in such a mirror configuration oscillates in response to the incident photons and subsequently re-emits fields where the propagation and electric field vectors have been inverted and the phase of the incident magnetic field is preserved. We proposed fabrication of sub-wavelength-scale conductive structures that could be used to interact with light at a nano-scale and enable synthesis of the desired perfect magnetic-field boundary condition. In a magnetic mirror, the interaction of light with the nanowires, dielectric layer and ground plate, inverts the magnetic field vector resulting in a zero degree phase shift upon reflection. Geometries such as split ring resonators and sinusoidal conductive strips were shown to demonstrate magnetic mirror behavior in the microwave and then in the visible. Work to design, fabricate and test a magnetic mirror began in 2007 at the NASA Goddard Space Flight Center (GSFC) under an Internal Research and Development (IRAD) award Our initial nanowire geometry was sinusoidal but orthogonally asymmetric in spatial frequency, which allowed clear indications of its behavior by polarization. We report on the fabrication steps and testing of magnetic mirrors using a phase shifting interferometer and the first far-field imaging of an optical magnetic mirror.

Diffraction suppressed mirrors having an invisible edge are disclosed for incident light at both targeted wavelengths and broadband incident light. The mirrors have a first having at least one discontiguous portion having a plurality of nanostructured apertures. The discontiguous mirror portion impedance matches a relatively high impedance portion of the mirror to a relatively low impedance portion of the mirror, thereby reducing the diffraction edge effect otherwise present in a conventional mirror.

When he first came to Dalat, Sarawak, a village of wooden homes by the Oya river in 1988, there was nothing for him to look forward to. The priestless St Bernard's Church was badly neglected while the 5,000 Melanau Roman Catholic residents led a casual but unchallenging life on the batang (river). Then Massang decided that something more had to be done for the Melanau youth in the Dalat township. Dalat was inaccessible until recently, with developments in the State. Even so, to reach it you'll need about three hours on the road to Sibu (if the muddy 34km stretch of the Selangau-Mukah road is in good condition), followed by a dangerous two-hour journey by sea-and-river (or a 25-minute flight by Twin Otter) to Mukah and from there, a 40-minute drive to reach Dalat.

Machine learning offers an intriguing alternative to first-principle analysis for discovering new physics from experimental data. However, to date, purely data-driven methods have only proven successful in uncovering physical laws describing simple, low-dimensional systems with low levels of noise. Here we demonstrate that combining a data-driven methodology with some general physical principles enables discovery of a quantitatively accurate model of a non-equilibrium spatially extended system from high-dimensional data that is both noisy and incomplete. We illustrate this using an experimental weakly turbulent fluid flow where only the velocity field is accessible. We also show that this hybrid approach allows reconstruction of the inaccessible variables – the pressure and forcing field driving the flow. Reinbold et al. propose a physics-informed data-driven approach that successfully discovers a dynamical model using high-dimensional, noisy and incomplete experimental data describing a weakly turbulent fluid flow. This approach is relevant to other non-equilibrium spatially-extended systems.

Coffee, cashew and avocado are of high socio-economic importance in many tropical smallholder farming systems around the globe. As plantation crops with a long lifespan, their cultivation requires long-term planning. The evaluation of climate change impacts on their biophysical suitability is therefore essential for developing adaptation measures and selecting appropriate varieties or crops. In this study, we modelled the current and future suitability of coffee arabica, cashew and avocado on a global scale based on climatic and soil requirements of the three crops. We used climate outputs of 14 global circulation models based on three emission scenarios to model the future (2050) climate change impacts on the crops both globally and in the main producing countries. For all three crops, climatic factors, mainly long dry seasons, mean temperatures (high and low), low minimum temperatures and annual precipitation (high and low), were more restrictive for the global extent of suitable growing regions than land and soil parameters, which were primarily low soil pH, unfavourable soil texture and steep slopes. We found shifts in suitable growing regions due to climate change with both regions of future expansion and contraction for all crops investigated. Coffee proved to be most vulnerable, with negative climate impacts dominating in all main producing regions. For both cashew and avocado, areas suitable for cultivation are expected to expand globally while in most main producing countries, the areas of highest suitability may decrease. The study reveals that climate change adaptation will be necessary in most major producing regions of all three crops. At high latitudes and high altitudes, however, they may all profit from increasing minimum temperatures. The study presents the first global assessment of climate change impacts on cashew and avocado suitability.

In this report, investigators in Germany detected the spread of the novel coronavirus (2019-nCoV) from a person who had recently traveled from China to Germany for a business trip. This transmission occurred before the apparent onset of illness in the index patient and was associated with additional transmission events in Germany.

This paper shows the importance of correcting for sample selection when investing in illiquid assets that trade endogenously. Using a sample of 32,928 paintings that sold repeatedly between 1960 and 2013, we find an asymmetric V-shaped relation between sale probabilities and returns. Adjusting for the resulting selection bias reduces average annual index returns from 8.7% to 6.3%, lowers Sharpe ratios from 0.27 to 0.11, and materially impacts portfolio allocations. Investing in a broad portfolio of paintings is not attractive, but targeting specific styles or top-selling artists may add value. The methodology naturally extends to other asset classes.