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Solid-state quantum acoustodynamic (QAD) systems provide a compact platform for quantum information storage and processing by coupling acoustic phonon sources with superconducting or spin qubits. The multi-mode composite high-overtone bulk acoustic wave resonator (HBAR) is a popular phonon source well suited for QAD. However, scattering from defects, grain boundaries, and interfacial/surface roughness in the composite transducer severely limits the phonon relaxation time in sputter-deposited devices. Here, we grow an epitaxial-HBAR, consisting of a metallic NbN bottom electrode and a piezoelectric GaN film on a SiC substrate. The acoustic impedance-matched epi-HBAR has a power injection efficiency >99% from transducer to phonon cavity. The smooth interfaces and low defect density reduce phonon losses, yielding ( f × Q ) and phonon lifetimes up to 1.36 × 10 17  Hz and 500 µs respectively. The GaN/NbN/SiC epi-HBAR is an electrically actuated, multi-mode phonon source that can be directly interfaced with NbN-based superconducting qubits or SiC-based spin qubits. Acoustic resonators may find application for qubit coupling in compact quantum information and processing systems. Here the authors show a multi-phonon source with high quality factors and long phonon lifetimes via epitaxial high-overtone bulk acoustic resonators.

Distinctly, Intermittent Water Supply networks cycle between filling, pressurized supply and draining, leading users to withdraw water and store it for later consumption. While intermittent networks serve one in five piped water users, their characteristic hydraulic features cannot be readily represented in available, open‐source hydraulic modeling software. Several hydraulic modeling methods have been proposed in the literature, but these methods disagree in their construction and assumptions, and most are not reproducible, hindering the exploration of techniques to improve the quality and equality of service in intermittent networks. To improve the reproducibility, consistency, and numerical stability of hydraulic models of intermittent supply, we synthesize the best modeling practices in the literature into a recommended, reproducible method: SWMM for Intermittent Networks (SWMMIN). We outline and demonstrate how SWMMIN models network pipes and user behavior: withdrawing water subject to available pressure in the network, storing water, and consuming from storage for their various activities. For experienced IWS modelers, we provide quantitative evidence of numerical stability and mass conservation within SWMMIN (from >1,000 simulations of 3 network models); we recommend spatial and temporal discretizations that result in solution speeds between 40 and 200 m/s. To facilitate the adoption of our recommended modeling procedures, we share a Python package (GOSWMMIN) that automates the implementation of SWMMIN. Lastly, we propose a model reporting template to bolster reproducibility and call on fellow modelers to use it; accessibly and reproducibly described models of intermittent supply have the potential to accelerate research and transform practice.

An electroluminescence (EL) phenomenon in unipolar-doped GaN/AlN/GaN double-barrier heterostructures—without any p-type contacts—was investigated from 4.2 K to 300 K. In the range of 200–300 K, the extracted peak photon energies agree with the Monemar formula. In the range of 30 to 200 K, the photon energies are consistent with A-exciton emission. At 4.2 K, the exciton type likely transforms into B-exciton. These studies confirm that the EL emission comes from a cross-bandgap (or band-to-band) electron-hole radiative recombination and is excitonic. The excitons are formed by the holes generated through interband tunneling and the electrons injected into the GaN emitter region of the GaN/AlN heterostructure devices.

Epitaxy is a process by which a thin layer of one crystal is deposited in an ordered fashion onto a substrate crystal. The direct epitaxial growth of semiconductor heterostructures on top of crystalline superconductors has proved challenging. Here, however, we report the successful use of molecular beam epitaxy to grow and integrate niobium nitride (NbN)-based superconductors with the wide-bandgap family of semiconductors—silicon carbide, gallium nitride (GaN) and aluminium gallium nitride (AlGaN). We apply molecular beam epitaxy to grow an AlGaN/GaN quantum-well heterostructure directly on top of an ultrathin crystalline NbN superconductor. The resulting high-mobility, two-dimensional electron gas in the semiconductor exhibits quantum oscillations, and thus enables a semiconductor transistor—an electronic gain element—to be grown and fabricated directly on a crystalline superconductor. Using the epitaxial superconductor as the source load of the transistor, we observe in the transistor output characteristics a negative differential resistance—a feature often used in amplifiers and oscillators. Our demonstration of the direct epitaxial growth of high-quality semiconductor heterostructures and devices on crystalline nitride superconductors opens up the possibility of combining the macroscopic quantum effects of superconductors with the electronic, photonic and piezoelectric properties of the group III/nitride semiconductor family. Group III/nitride semiconductors have been grown epitaxially on the superconductor niobium nitride, allowing the superconductor’s macroscopic quantum effects to be combined with the semiconductors’ electronic, photonic and piezoelectric properties. Mix and match The perfect epitaxial growth of one crystalline semiconductor on another is a fundamental feature of many high-performance electronic and optoelectronic devices. Rusen Yan and colleagues demonstrate that a similar level of epitaxial integration can be achieved between the group III nitride semiconductors and the superconducting nitride metal NbN x . This ability to grow highly ordered, high-quality semiconducting structures directly on a crystalline superconductor provides a route for exploring a host of new device possibilities that combine the properties of the two subsystems.

Despite efforts to expand infrastructure, billions of people still lack access to essential services. Traditional scaling-law (power-law) models of infrastructure estimate the size of infrastructure based on a city’s population, obscuring the consequences of inadequate access. Instead, we model infrastructure size as a power-law function of the population served by the infrastructure (not total population). This generalization better fitted data describing 6898 water and sewer networks in 53 countries—improving R2 by up to 32%. Even in cities with little access to infrastructure, we found economies of scale: infrastructure that serves more people can do so with less per beneficiary. Uniquely, our generalized scaling laws can model the infrastructure needed to expand access. We validate with 16 years of data from 3391 water and sewer networks in Brazil. If economies of scale are exploited at the cost of inter-city equality, sewer access can expand from 54% to 90% of Brazil’s population with 29% (89 000 km) fewer new sewers. Benefit- and equality-maximizing strategies to achieve universal access in Brazil differ by 220 million people-years of access. Our generalized model can estimate the infrastructure needed to expand access and quantify trade-offs between the benefits and equality of access expansions.

NFPA and EN design standards for systems of firefighting foams devolve the problem of flow calculations for each foam concentrate to the product manufacturers. The data provided by manufacturers do not represent the engineering specifications needed for foam system design. This contribution examines the rheology of foam concentrates, comprising three FfreeF (fluorine-free foams) and one AR-AFFF (alcohol-resistant aqueous film-forming foam). These foam concentrates comprise solutions of polymers (predominantly polysaccharides) combined with surfactants and solvents. We reveal that all products exhibit significant shear thinning and that the formulations display substantial yield stress and slow response to changes in stress. These foam concentrates are sensitive to shearing and require many hours to recover from any deformation during handling. These non-Newtonian properties of the concentrates arise mainly from the presence of polysaccharides in their chemical make-up. We provide guidance for the types of measurement needed to provide engineering specifications for fire system designers and the limits of use for these measurements. The contribution highlights the design implications of the slow-yielding foam concentrates for design of foam-based fire-suppression systems.

Cross-gap light emission is reported in n-type unipolar GaN/AlN double-barrier heterostructure diodes at room temperature. Three different designs were grown on semi-insulating bulk GaN substrates using molecular beam epitaxy (MBE). All samples displayed a single electroluminescent spectral peak at 360 nm with full-width at half-maximum (FWHM) values no greater than 16 nm and an external quantum efficiency (EQE) of [ap]0.0074% at 18.8 mA. In contrast to traditional GaN light emitters, p-type doping and p-contacts are completely avoided, and instead, holes are created in the GaN on the emitter side of the tunneling structure by direct interband (that is, Zener) tunneling from the valence band to the conduction band on the collector side. The Zener tunneling is enhanced by the high electric fields (~5 × 106 V cm-1 ) created by the notably large polarization-induced sheet charge at the interfaces between the AlN and GaN.

The disposal of misfolded proteins from the lumen of the endoplasmic reticulum (ER) is one of the quality control mechanisms present in the protein secretory pathway. Through ER-associated degradation, misfolded substrates are targeted to the cytosol where they are degraded by the proteasome. We have identified four maize (Zea mays) Der1-like genes (Zm Derlins) that encode homologs of Der1p, a yeast (Saccharomyces cerevisiae) protein implicated in ER-associated degradation. Zm Derlins are capable of functionally complementing a yeast Der1 deletion mutant. Such complementation indicates that the Der1p function is conserved among species. Zm Derlin genes are expressed at low levels throughout the plant, but appear prevalent in tissues with high activity of secretory protein accumulation, including developing endosperm cells. Expression of three of the four Zm Derlin genes increases during ER stress, with Zm Derlin1-1 showing the strongest induction. Subcellular fractionation experiments localized Zm Derlin proteins to the membrane fraction of microsomes. In maize endosperm, Zm Derlin proteins were found primarily associated with ER-derived protein bodies regardless of the presence of an ER stress response.

The new Koffman Southern Tier Incubator (KSTI) in Binghamton, New York is a three story facility that provides laboratories and shared facilities for start-up companies. The purpose of the facility is to offer resources and promote growth until these companies are strong enough to graduate from the incubator. Tenants have access to any available space, admission to all events hosted by the Incubator, and the ability to book the conference or event room. Information about the project's HVAC design parameters and corresponding design challenges is also offered.

We used whole genome scan association mapping to identify loci with major effect on oleic acid content in maize kernels. Single nucleotide polymorphism haplotypes at 8,590 loci were tested for association with oleic acid content in 553 maize inbreds. A single locus with major effect on oleic acid was mapped between 380 and 384 cM in the IBM2 neighbors genetic map on chromosome 4 and confirmed in a biparental population. A fatty acid desaturase, fad2, identified ~2 kb from the associated genetic marker, is the most likely candidate gene responsible for the differences in the phenotype. The fad2 alleles with high- and low-oleic acid content were sequenced and allelic differences in fad2 RNA level in developing embryos was investigated. We propose that a non-conservative amino acid polymorphism near the active site of fad2 contributes to the effect on oleic acid content. This is the first report of the use of a high resolution whole genome scan association mapping where a putative gene responsible for a quantitative trait was identified in plants.