gebhart/patrepeval huggingface dataset:
Theory of the strain-symmetrized silicon-based Ge-Si superlattice laser (1998)

A unipolar p-i-p silicon-based intersubband laser consisting of a symmetrically strained GeSi superlattice on a relaxed Si/sub 0.5/Ge/sub 0.5/ buffer layer is modeled and analyzed. The strain-symmetrization removes the limitation on the size of the superlattice. The procedure for calculating the in-plane energy dispersion is extended to a superlattice. Analysis of the in-plane energy dispersion shows that the population inversion is local-in-k-space. For an 11 ML/11 ML superlattice (15.4 /spl Aring//15.4 /spl Aring/), interminiband lasing between HH2 and HH1 is predicted at /spl lambda/=2.2 /spl mu/m. From the envelope functions and material properties, the miniband lifetimes and laser gain are calculated. For a current density of 10 kA/cm/sup 2/, a gain of G/sub L/=96/cm is calculated. Alternate structures with larger expected gains are considered. Quantum-parallel, quantum-cascade, and quantum-staircase lasing are examined.
Nitrogen Enriched Combustion of a Natural Gas Engine to Reduce NOx Emissions (2004)

Nitrogen enrichment of intake air is proposed as an alternative to Exhaust Gas Recirculation (EGR). Experimental results of nitrogen enriched combustion of a Kohler M12 engine (converted to operate with natural gas) are presented in this paper. A 70% reduction in NOx emissions was observed at full load (4 kW) and ignition timing (IT) equal to −20 ATDC with 2.1% NO2 enrichment (40 slpm). However, NOx reduction was minimal at lower loads. The effect of spark or ignition timing along with nitrogen enrichment is also reported for full load. It is recognized that advancing the ignition timing from conventional values has more advantages than retarding the same. A 68% reduction in NOx and a 0.8% drop in Fuel Conversion Efficiency (FCE) were observed at −30 ATDC ignition timing. However, the maximum ignition timing advance with stable engine operation was limited to −40 ATDC. Some of the drawbacks encountered were engine misfire at higher concentrations of nitrogen-rich air and retarded spark timing resulting in poor FCE.
Bandgap Engineering of Coal-Derived Graphene Quantum Dots (2015)

Bandgaps of photoluminescent graphene quantum dots (GQDs) synthesized from anthracite have been engineered by controlling the size of GQDs in two ways: either chemical oxidative treatment and separation by cross-flow ultrafiltration, or by a facile one-step chemical synthesis using successively higher temperatures to render smaller GQDs. Using these methods, GQDs were synthesized with tailored sizes and bandgaps. The GQDs emit light from blue-green (2.9 eV) to orange-red (2.05 eV), depending on size, functionalities and defects. These findings provide a deeper insight into the nature of coal-derived GQDs and demonstrate a scalable method for production of GQDs with the desired bandgaps.
Novel high-resolution computed tomography-based radiomic classifier for screen-identified pulmonary nodules in the National Lung Screening Trial (2018)

Our novel radiomic LDCT-based approach for indeterminate screen-detected nodule characterization appears extremely promising however independent external validation is needed.
Synthesis of Poly(arylene ether ether ketone ketone) Copolymers Containing Pendant Sulfonic Acid Groups Bonded to Naphthalene as Proton Exchange Membrane Materials (2004)

A new series of wholly aromatic poly(ether ether ketone ketone) containing pendant sulfonic acid groups (SPAEEKK) were conveniently prepared by potassium carbonate mediated nucleophilic polycondensation reactions of inexpensive commercially available monomers 1,3-bis(4-fluorobenzoyl)benzene (BFBB), sodium 6,7-dihydroxy-2-naphthalenesulfonate (DHNS), and 4,4‘-biphenol or hydroquinone in N-methyl-2-pyrrolidone (NMP) at 170 °C. FT-IR and NMR were used to characterize the structures and the sulfonate or sulfonic acid contents (SC) of the polymers. Flexible membrane films were obtained by casting N,N-dimethylacetamide (DMAc) solutions of copolymers. Membrane films in acid form were then obtained by treating the sodium form membrane films in 2 N sulfuric acid at room temperature. Glass-transition temperatures (Tg's) and decomposition temperatures (Td's) of SPAEEKKs in both sodium and acid forms were determined. Water uptake and swelling ratio values increased with SCs and temperatures. The proton conductivities of acid form membrane films increased with SC value and temperature and reached 5.6 × 10-2 S/cm at 100 °C for SPAEEKK-100.
Scaling Structure of Electrocardiographic Waveform During Prolonged Ventricular Fibrillation in Swine (2000)

Ventricular fibrillation (VF) is the most common arrhythmia causing sudden cardiac death. However, the likelihood of successful defibrillation declines with increasing duration of VF. Because the morphology of the electrocardiogram (ECG) waveform during VF also changes with time, this study examined a new measure that describes the VF waveform and distinguishes between early and late VF. Surface ECG recordings were digitized at 200 samples/s from nine swine with induced VF. A new measure called the scaling exponent was calculated by examining the power-law relationship between the summation of amplitudes of a 1,024-point (5.12 second) waveform segment and the time scale of measurement. The scaling exponent is a local estimate of the fractal dimension of the ECG waveform. A consistent power-law relationship was observed for measurement time scales of 0.005-0.040 seconds. Calculation of the scaling exponent produced similar results between subjects, and distinguished early VF (< 4-minute duration) from late VF (> or = 4-minute duration). The scaling exponent was dependent on the order of the data, supporting the hypothesis that the surface ECG during VF is a deterministic rather than a random signal. The waveform of VF results from the interaction of multiple fronts of depolarization within the heart, and may be described using the tools of nonlinear dynamics. As a quantitative descriptor of waveform structure, the scaling exponent characterizes the time dependent organization of VF.
Efficient Metal-Free Electrocatalysts for Oxygen Reduction: Polyaniline-Derived N- and O-Doped Mesoporous Carbons (2013)

The oxygen reduction reaction (ORR)-one of the two half-reactions in fuel cells-is one of the bottlenecks that has prevented fuel cells from finding a wide range of applications today. This is because ORR is inherently a sluggish reaction; it is also because inexpensive and sustainable ORR electrocatalysts that are not only efficient but also are based on earth-abundant elements are hard to come by. Herein we report the synthesis of novel carbon-based materials that can contribute to solving these challenges associated with ORR. Mesoporous oxygen- and nitrogen-doped carbons were synthesized from in situ polymerized mesoporous silica-supported polyaniline (PANI) by carbonization of the latter, followed by etching away the mesoporous silica template from it. The synthetic method also allowed the immobilization of different metals such as Fe and Co easily into the system. While all the resulting materials showed outstanding electrocatalytic activity toward ORR, the metal-free, PANI-derived mesoporous carbon (dubbed PDMC), in particular, exhibited the highest activity, challenging conventional paradigms. This unprecedented activity by the metal-free PDMC toward ORR was attributed to the synergetic activities of nitrogen and oxygen (or hydroxyl) species that were implanted in it by PANI/mesoporous silica during pyrolysis.
High-frequency modulation without the relaxation oscillation resonance in quantum cascade lasers (2001)

Quantum cascade (QC) lasers, based on intersubband transitions in semiconductor quantum wells, are characterized by ultrafast (picosecond) carrier lifetimes. An important consequence of this unique property is the expected absence of relaxation oscillations in the transient response of these devices. Here, we discuss and experimentally verify this prediction by measuring the modulation response of several 8-μm-QC lasers, properly processed and packaged for high-speed operation, up to 10 GHz.
Thermocouple Rakes for Measuring Boundary Layer Flows Extremely Close to Surface (2001)

Of vital interest to aerodynamic researchers is precise knowledge of the flow velocity profile next to the surface. This information is needed for turbulence model development and the calculation of viscous shear force. Though many instruments can determine the flow velocity profile near the surface, none of them can make measurements closer than approximately 0.01 in. from the surface. The thermocouple boundary-layer rake can measure much closer to the surface than conventional instruments can, such as a total pressure boundary layer rake, hot wire, or hot film. By embedding the sensors (thermocouples) in the region where the velocity is equivalent to the velocity ahead of a constant thickness strut, the boundary-layer flow profile can be obtained. The present device fabricated at the NASA Glenn Research Center microsystem clean room has a heater made of platinum and thermocouples made of platinum and gold. Equal numbers of thermocouples are placed both upstream and downstream of the heater, so that the voltage generated by each pair at the same distance from the surface is indicative of the difference in temperature between the upstream and downstream thermocouple locations. This voltage differential is a function of the flow velocity, and like the conventional total pressure rake, it can provide the velocity profile. In order to measure flow extremely close to the surface, the strut is made of fused quartz with extremely low heat conductivity. A large size thermocouple boundary layer rake is shown in the following photo. The latest medium size sensors already provide smooth velocity profiles well into the boundary layer, as close as 0.0025 in. from the surface. This is about 4 times closer to the surface than the previously used total pressure rakes. This device also has the advantage of providing the flow profile of separated flow and also it is possible to measure simultaneous turbulence levels within the boundary layer.
Fault location in three-terminal line with use of limited measurements (2005)

Limited availability of measurements, i.e. one-end measurements with additional information on amplitudes of load currents from the remote sections, for locating faults on three- terminal power line is considered. The delivered fault location algorithm consists of three subroutines designated for locating faults in particular sections of the line. In case of the subroutines for the sections, which are not adjacent to the main measurement terminal, the analytic shift of measurements to the tap point is applied. Special selection procedure is used for indication of the valid subroutine. The delivered fault location technique has been tested with the fault data obtained from versatile ATP-EMTP simulations. The sample examples are reported and discussed.
12-lead surface electrocardiogram reconstruction from implanted device electrograms (2010)

After individual post-implantation correlation with the surface EKG, reconstruction using a time-independent transfer matrix accurately reproduces the surface EKG, is free from gating requirements, and retains validity during aberrant depolarization. These findings have significant implications for further study relating IC electrogram to surface tracings. The techniques may be used for real-time or remote monitoring and diagnosis of rhythm disturbances, cardiac ischaemia, and lead integrity and stability.
Server liquid cooling with chiller-less data center design to enable significant energy savings (2012)

This paper summarizes the concept design and hardware build efforts as part of a US Department of Energy cost shared grant, two year project (2010–2012) that was undertaken to develop highly energy efficient, warm liquid cooled servers for use in chiller-less data centers. Significant savings are expected in data center energy, refrigerant and make up water use. The technologies being developed include liquid cooling hardware for high volume servers, advanced thermal interface materials, and dry air heat exchanger (chiller-less with all year “economizer”) based facility level cooling systems that reject the Information Technology (IT) equipment heat load directly to the outside ambient air. Substantial effort has also been devoted towards exploring the use of high volume manufacturable components and cost optimized cooling designs that address high volume market design points. Demonstration hardware for server liquid cooling and data center economizer based cooling has been built and is operational for a 15 kW rack fully populated with liquid cooled servers. This design allows the use of up to 45 °C liquid coolant to the rack. Data collection has commenced to document the system thermal performance and energy usage using sophisticated instrumentation and data collection software methodologies. The anticipated benefits of such energy-centric configurations are significant energy savings at the data center level of as much as 30% and energy-proportional cooling in real time based on IT load and ambient air temperatures. The objective of this project is to reduce the cooling energy to 5% or less of a comparable typical air cooled chiller based total data center energy. Additional energy savings can be realized by reducing the IT power itself through reduced server fan power and potentially less leakage power due to lower device temperatures on average for most locations. This paper focuses on the server liquid cooling, the rack enclosure with heat exchanger cooling and liquid distribution, and the data center level cooling infrastructure. A sample of recently collected energy-efficiency data is also presented to provide experimental validation of the concept demonstrating cooling energy use to be less than 3.5% of the IT power for a hot summer day in New York.
<title>Phase variations in a fluctuation-based processor</title> (1996)

Fluctuations are always present in underwater sound propagation, and are generally viewed as a complication in signal detection and identification. However, in some cases where the signals fluctuate less than the noise, it is possible to take advantage of the different magnitudes of fluctuations of signal and noise to improve detection. Wagstaff's integration silencing processor (WISPR) is an example of such a processor. The original version of the WISPR processor utilized power values derived from complex pressures in a given frequency bin, but ignored the phases of these complex pressures. An improved processor that takes advantage of the phase as well as the amplitude is described below. Its performance is verified using measured data, where detection has been accomplished by a margin of 4 decibels. Simulations using synthetic data show that the new processor can be effective for signal-to-noise ratios greater than minus 20 decibels.
Rapid Diagnosis of Nocardiosis with an Enzyme Immunoassay (1987)

Diagnosis of nocardiosis is often delayed because of the frequently nonspecific nature of the illness and because of the long incubation period required to isolate the organism in the microbiology laboratory. Past experience with serological methods for diagnosing nocardiosis have met with little success, primarily because there was no suitable antigen. Using a previously identified Nocardia asteroides-specific protein, we developed an enzyme immunoassay for the rapid diagnosis of nocardiosis. We evaluated sera from 22 patients with nocardiosis, 83 hospitalized controls, and 21 patients with tuberculosis. Twenty (91%) of the sera from patients with nocardiosis had titers of antibody greater than or equal to 1:256, whereas all of the sera from controls and from patients with tuberculosis had titers less than 1:256. This assay represents a highly sensitive and specific serodiagnostic tool for evaluating patients with possible nocardiosis.
A Laminar Flow-Based Microfluidic Tesla Pump via Lithography Enabled 3D Printing (2016)

Tesla turbine and its applications in power generation and fluid flow were demonstrated by Nicholas Tesla in 1913. However, its real-world implementations were limited by the difficulty to maintain laminar flow between rotor disks, transient efficiencies during rotor acceleration, and the lack of other applications that fully utilize the continuous flow outputs. All of the aforementioned limits of Tesla turbines can be addressed by scaling to the microfluidic flow regime. Demonstrated here is a microscale Tesla pump designed and fabricated using a Digital Light Processing (DLP) based 3D printer with 43 µm lateral and 30 µm thickness resolutions. The miniaturized pump is characterized by low Reynolds number of 1000 and a flow rate of up to 12.6 mL/min at 1200 rpm, unloaded. It is capable of driving a mixer network to generate microfluidic gradient. The continuous, laminar flow from Tesla turbines is well-suited to the needs of flow-sensitive microfluidics, where the integrated pump will enable numerous compact lab-on-a-chip applications.
NOx Adsorber Desulfation Techniques for Heavy-Duty On-Highway Diesel Engines (2002)

<div class="htmlview paragraph">A 5.9 liter medium-heavy-duty diesel engine, equipped with a diesel exhaust emission control system consisting of catalyzed diesel particulate filters (CDPF) and NOx adsorber catalysts arranged in a dual-path configuration, was evaluated with the goal of developing desulfation strategies for in-use NOx adsorber desulfation. NOx adsorber desulfation was accomplished by providing reductant via a secondary exhaust fuel injection system and exhaust flow via an exhaust bypass valve. An alternating restriction of the exhaust flow between the two flow paths allowed reductant injection and adsorber desulfation to occur under very low space velocity conditions. An exhaust bypass valve connecting the dual path configuration upstream of the catalyzed diesel particulate filters allowed controlled addition of exhaust into the desulfating pathway for desulfation method development. Exotherms from the oxidation of reductant on the CDPF, and subsequent convective heat transfer from the CDPF to the NOx adsorbers generated adsorber catalyst temperatures in excess of 750°C. The control of space velocity through the desulfating pathway minimized cooling, allowing the temperature to be held in the target desulfation temperature range for prolonged periods of time. Sulfur release in the form of hydrogen sulfide and sulfur dioxide was measured using a chemical ionization mass spectrometer.</div>
A Nonparametric Temperature Controller With Nonlinear Negative Reaction for Multi-Point Rapid MR-Guided HIFU Ablation (2014)

Magnetic resonance-guided high intensity focused ultrasound (MRgHIFU) is a noninvasive method for thermal ablation, which exploits the capabilities of magnetic resonance imaging (MRI) for excellent visualization of the target and for near real-time thermometry. Oncological quality of ablation may be obtained by volumetric sonication under automatic feedback control of the temperature. For this purpose, a new nonparametric (i.e., model independent) temperature controller, using nonlinear negative reaction, was designed and evaluated for the iterated sonication of a prescribed pattern of foci. The main objective was to achieve the same thermal history at each sonication point during volumetric MRgHIFU. Differently sized linear and circular trajectories were investigated ex vivo and in vivo using a phased-array HIFU transducer. A clinical 3T MRI scanner was used and the temperature elevation was measured in five slices simultaneously with a voxel size of 1 ×1 ×5 mm(3) and temporal resolution of 4 s. In vivo results indicated a similar thermal history of each sonicated focus along the prescribed pattern, that was 17.3 ± 0.5 °C as compared to 16 °C prescribed temperature elevation. The spatio-temporal control of the temperature also enabled meaningful comparison of various sonication patterns in terms of dosimetry and near-field safety. The thermal build-up tended to drift downwards in the HIFU transducer with a circular scan.
Metabolic Engineering of a Phosphoketolase Pathway for Pentose Catabolism in <i>Saccharomyces cerevisiae</i> (2004)

Low ethanol yields on xylose hamper economically viable ethanol production from hemicellulose-rich plant material with Saccharomyces cerevisiae. A major obstacle is the limited capacity of yeast for anaerobic reoxidation of NADH. Net reoxidation of NADH could potentially be achieved by channeling carbon fluxes through a recombinant phosphoketolase pathway. By heterologous expression of phosphotransacetylase and acetaldehyde dehydrogenase in combination with the native phosphoketolase, we installed a functional phosphoketolase pathway in the xylose-fermenting Saccharomyces cerevisiae strain TMB3001c. Consequently the ethanol yield was increased by 25% because less of the by-product xylitol was formed. The flux through the recombinant phosphoketolase pathway was about 30% of the optimum flux that would be required to completely eliminate xylitol and glycerol accumulation. Further overexpression of phosphoketolase, however, increased acetate accumulation and reduced the fermentation rate. By combining the phosphoketolase pathway with the ald6 mutation, which reduced acetate formation, a strain with an ethanol yield 20% higher and a xylose fermentation rate 40% higher than those of its parent was engineered.
Cylindrical Rotating Triboelectric Nanogenerator (2013)

We demonstrate a cylindrical rotating triboelectric nanogenerator (TENG) based on sliding electrification for harvesting mechanical energy from rotational motion. The rotating TENG is based on a core-shell structure that is made of distinctly different triboelectric materials with alternative strip structures on the surface. The charge transfer is strengthened with the formation of polymer nanoparticles on surfaces. During coaxial rotation, a contact-induced electrification and the relative sliding between the contact surfaces of the core and the shell result in an "in-plane" lateral polarization, which drives the flow of electrons in the external load. A power density of 36.9 W/m(2) (short-circuit current of 90 μA and open-circuit voltage of 410 V) has been achieved by a rotating TENG with 8 strip units at a linear rotational velocity of 1.33 m/s (a rotation rate of 1000 r/min). The output can be further enhanced by integrating more strip units and/or applying larger linear rotational velocity. This rotating TENG can be used as a direct power source to drive small electronics, such as LED bulbs. This study proves the possibility to harvest mechanical energy by TENGs from rotational motion, demonstrating its potential for harvesting the flow energy of air or water for applications such as self-powered environmental sensors and wildlife tracking devices.
Optical Detection of SARS-CoV-2 Utilizing Antigen-Antibody Binding Interactions (2021)

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for the coronavirus disease (COVID-19) pandemic, is sweeping the world today. This study investigates the optical detection of SARS-CoV-2, utilizing the antigen-antibody binding interactions utilizing a light source from a smart phone and a portable spectrophotometer. The proof-of-concept is shown by detecting soluble preparations of spike protein subunits from SARS-CoV-2, followed by detection of the actual binding potential of the SARS-CoV-2 proteins with their corresponding antigens. The measured binding interactions for RBD and NCP proteins with their corresponding antibodies under different conditions have been measured and analyzed. Based on these observations, a "hump or spike" in light intensity is observed when a specific molecular interaction takes place between two proteins. The optical responses could further be analyzed using the principle component analysis technique to enhance and allows precise detection of the specific target in a multi-protein mixture.