gebhart/patrepeval huggingface dataset:
Removal of all time-varying sea-surface effects by source deghosting and demultiple (2019)

ABSTRACT Seismic source deghosting and sea-surface-related demultiple have been long-standing problems in marine seismic data processing. Although the receiver ghost problem may be considered as solved by using collocated measurement of pressure and normal velocity wavefields, the source deghosting and demultiple algorithms are still limited by assumptions related to the sea-surface condition. We have investigated the impact of a time-varying rough sea surface on source deghosting and demultiple. Starting from Rayleigh’s reciprocity theorem for time-varying sea surfaces, we uncover a fundamental limitation for source deghosting of time-dependent wavefields, such as marine seismic data that contain a receiver ghost or sea-surface-related multiples. We use simple synthetic examples to study the impact of source deghosting on sea-surface-related multiples. To resolve this limitation, we derive a method for simultaneous source deghosting and sea-surface-related demultiple for time-variant wavefields. Finally, we use the complex geologic model Sigsbee 2B first to illustrate that the source deghosting operation brings significant errors when applied to a data set containing sea-surface multiples. Second, we find that this problem can be resolved by simultaneously performing source deghosting and demultiple operations even in the presence of time-varying sea surfaces.
Reservations inside clusters of all‐optical core nodes achieve distributed burst aggregation and switching improving efficiency and loss (2007)

Abstract Clustering neighbouring nodes of an all‐optical core network into medium‐sized rings controlled by a master node allows two‐way reservation‐based control to aggregate bursts destined for other clusters in a lossless way with tolerable delay. The densely packed bursts can then be sent over static or switched light paths and be received in the destination cluster ring without the delay of end‐to‐end reservations. This hybrid approach where two‐way reservations are geographically limited inside clusters only avoids both the handicap of heavy loss of one‐way Optical Burst Switching (OBS) and the intolerable delay and multiplexing gain of end‐to‐end reservations. In addition, the number of multi‐port space‐switching all‐optical nodes is reduced delegating part of this function to the distributed control of the laser sources of the ring under the guidance of the medium access protocol. Copyright © 2007 John Wiley & Sons, Ltd.
A surface-micromachined optical self-homodyne polarimetric sensor for noninvasive glucose monitoring (2000)

A surface micromachined, highly sensitive optical polarimetric sensor using a self-homodyne coherent detection method has been demonstrated. By detecting the small polarization rotation of polarized laser light passing through a glucose-containing fluid, this sensor is suitable for noninvasive glucose monitoring for diabetes patients. A resolution glucose level of 75 mg/dl has been obtained, with a 0.9956 correlation coefficient between the reference and the measured values. This polarimeter has the advantages of full system integration and compatibility with silicon processing industry, which makes an integrated, low-cost noninvasive glucose sensor feasible.
Exciton Correlations in Intramolecular Singlet Fission (2016)

We have synthesized a series of asymmetric pentacene-tetracene heterodimers with a variable-length conjugated bridge that undergo fast and efficient intramolecular singlet fission (iSF). These compounds have distinct singlet and triplet energies, which allow us to study the spatial dynamics of excitons during the iSF process, including the significant role of exciton correlations in promoting triplet pair generation and recombination. We demonstrate that the primary photoexcitations in conjugated dimers are delocalized singlets that enable fast and efficient iSF. However, in these asymmetric dimers, the singlet becomes more localized on the lower energy unit as the length of the bridge is increased, slowing down iSF relative to analogous symmetric dimers. We resolve the recombination kinetics of the inequivalent triplets produced via iSF, and find that they primarily decay via concerted processes. By identifying different decay channels, including delayed fluorescence via triplet-triplet annihilation, we can separate transient species corresponding to both correlated triplet pairs and uncorrelated triplets. Recombination of the triplet pair proceeds rapidly despite our experimental and theoretical demonstration that individual triplets are highly localized and unable to be transported across the conjugated linker. In this class of compounds, the rate of formation and yield of uncorrelated triplets increases with bridge length. Overall, these constrained, asymmetric systems provide a unique platform to isolate and study transient species essential for singlet fission, which are otherwise difficult to observe in symmetric dimers or condensed phases.
Demosaiced pixel super-resolution in digital holography for multiplexed computational color imaging on-a-chip (Conference Presentation) (2017)

Digital holographic on-chip microscopy achieves large space-bandwidth-products (e.g., >1 billion) by making use of pixel super-resolution techniques. To synthesize a digital holographic color image, one can take three sets of holograms representing the red (R), green (G) and blue (B) parts of the spectrum and digitally combine them to synthesize a color image. The data acquisition efficiency of this sequential illumination process can be improved by 3-fold using wavelength-multiplexed R, G and B illumination that simultaneously illuminates the sample, and using a Bayer color image sensor with known or calibrated transmission spectra to digitally demultiplex these three wavelength channels. This demultiplexing step is conventionally used with interpolation-based Bayer demosaicing methods. However, because the pixels of different color channels on a Bayer image sensor chip are not at the same physical location, conventional interpolation-based demosaicing process generates strong color artifacts, especially at rapidly oscillating hologram fringes, which become even more pronounced through digital wave propagation and phase retrieval processes. Here, we demonstrate that by merging the pixel super-resolution framework into the demultiplexing process, such color artifacts can be greatly suppressed. This novel technique, termed demosaiced pixel super-resolution (D-PSR) for digital holographic imaging, achieves very similar color imaging performance compared to conventional sequential R,G,B illumination, with 3-fold improvement in image acquisition time and data-efficiency. We successfully demonstrated the color imaging performance of this approach by imaging stained Pap smears. The D-PSR technique is broadly applicable to high-throughput, high-resolution digital holographic color microscopy techniques that can be used in resource-limited-settings and point-of-care offices.
Islet amyloid: From fundamental biophysics to mechanisms of cytotoxicity (2013)

Pancreatic islet amyloid is a characteristic feature of type 2 diabetes. The major protein component of islet amyloid is the polypeptide hormone known as islet amyloid polypeptide (IAPP, or amylin). IAPP is stored with insulin in the β-cell secretory granules and is released in response to the stimuli that lead to insulin secretion. IAPP is normally soluble and is natively unfolded in its monomeric state, but forms islet amyloid in type 2 diabetes. Islet amyloid is not the cause of type 2 diabetes, but it leads to β-cell dysfunction and cell death, and contributes to the failure of islet cell transplantation. The mechanism of IAPP amyloid formation is not understood and the mechanisms of cytotoxicity are not fully defined.
Synthesis of Angular Benzodipyrazoles and Related Systems (1991)

A series of benzo [1,2-c:3,4-c']dipyrazoles was prepared from cyclohexane-1,3-dione. Several related systems with different central rings were also prepared. In addition, benzo[1,2-c:4,3-c']dipyrazoles were synthesized from 1,4-cyclohexanedione monoethylene ketal
Three-dimensional data storage using the photochromic protein bacteriorhodopsin (2002)

A three-dimensional computer memory architecture based on the optical properties of the integral membrane protein bacteriorhodopsin has been previously proposed. However, confirmation of the very important branched photocycle property of this protein has not been shown. Data confirming the existence of a branched photocycle by writing a long term stable bit of information within the center of a cube of protein is presented. The stable photoproduct is formed by pulsing a 635 nm laser followed by an intersecting 690 nm laser pulse. At the point of intersection a stable branched photo-product appears. We found that at elevated temperatures the rate of production of the stable photoproduct is greatly increased and therefore the experiments are performed at 40/spl deg/C. Data representing absorbance changes at 690 nm due to the bacteriorhodopsin photocycle at 40/spl deg/C is presented. This information is required to set the timing of the light pulses required to write a bit. Then the pulse-pulse experiment is performed with a corresponding increase in transmission observed during the 690 nm light pulse. This confirms the production of the stable photoproduct. The experiment is then repeated with both lasers pulsing simultaneously. If the photoproduct is formed from a branch off of the photocycle, the simultaneous pulses should form much less photoproduct, despite an equivalent number of photons. Data showing this result is presented confirming the branched production of the stable photoproduct, thus proving the three dimensional computer memory architecture.
Enhancing spectral efficiency of binary NRZ optical networks with electronic signal processing (2006)

We have analyzed a scheme using electrical prefiltering at the transmitter and electronic signal processing at the receiver to enhance the spectral efficiency of binary non-return-to-zero (NRZ) wavelength-division-multiplexed (WDM) networks consisting of typical terrestrial dispersion maps employing standard single-mode fiber (SSMF) and erbium-doped fiber amplifiers (EDFAs). Our analysis shows that up to 1.6 bits/s/Hz of spectral efficiency is achievable using this technique with orthogonal polarization launch of alternate channels in 10.7 Gb/s binary NRZ systems for transmission distances up to 800 km typically used in metropolitan optical networks.
A Practical Method For Stabilizing Lithiated Halogenated Aromatic Compounds (2008)

An exothermic decomposition was observed during a metalation/acylation of 3,4-difluoroanisole (5), resulting in a significant thermal hazard. The lithiated anion 6 was found to decompose exothermically at temperatures above −47 °C showing an adiabatic temperature rise at a peak rate of 120 °C/min. A literature search revealed similar observations for metalation/acylation in analogous aromatic difluoro compounds. This sequence of reactions was evaluated thermochemically. Control experiments at −55 °C over 2 h indicated anion 6 was stable at temperatures below −55 °C under dilute reaction concentrations. This runaway hazard could be addressed using MgCl2 to stabilize the reactive species and thereby decrease its decomposition rate. Thermochemical experiments suggested MgCl2 forms a weak interaction with lithiated species 6, rather than via complete lithium−magnesium exchange. The process was successfully piloted on a multikilo scale by use of MgCl2 as an additive.
2-Acetylpyridine thiosemicarbazones. 1. A new class of potential antimalarial agents (1979)

Based on the antimalarial properties observed for 2-acetylpyridine 4-phenyl-3-thiosemicarbazone (1), an extensive series of related thiosemicarbazones was prepared and tested against Plasmodium berghei in mice. Screening results indicated that the presence of the 2-pyridylethylidene group was critical and that certain phenyl, benzyl, phenethyl, or cycloalkyl groups at N4 of the thiosemicarbazone moiety also contribute to antimalarial activity.
In vitro T lymphopoiesis of human and rhesus CD34+ progenitor cells (1996)

Differentiation of hematopoietic progenitor cells into T lymphocytes generally occurs in the unique environment of the thymus, a feature that has hindered efforts to model this process in the laboratory. We now report that thymic stromal cultures from rhesus macaques can support T-cell differentiation of human or rhesus CD34+ progenitor cells. Culture of rhesus or human CD34+ bone marrow-derived cells depleted of CD34+ lymphocytes on rhesus thymic stromal monolayers yielded CD3+CD4+CD8+, CD3+CD4+CD8-, and CD3+CD4-CD8+ cells after 10 to 14 days. In addition to classical T lymphocytes, a discrete population of CD3+CD8loCD16+CD56+ cells was detected after 14 days in cultures inoculated with rhesus CD34+ cells. CD3+ T cells arising from these cultures were not derived from contaminating T cells present in the CD34+ cells used to inoculate thymic stromal monolayers or from the thymic monolayers, as shown by labeling of cells with the lipophilic membrane dye PKH26. Expression of the recombinase activation gene RAG-2, which is selectively expressed in developing lymphocytes, was detectable in thymic cultures inoculated with CD34+ cells but not in CD34+ cells before thymic culture or in thymic stromal monolayers alone. Reverse transcriptase-polymerase chain reaction analysis of T cells derived from thymic stromal cultures of rhesus and human CD34+ cells showed a polyclonal T-cell receptor repertoire. T-cell progeny derived from rhesus CD34+ cells cultured on thymic stroma supported vigorous simian immunodeficiency virus replication in the absence of exogenous mitogenic stimuli. Rhesus thymic stromal cultures provide a convenient means to analyze T-cell differentiation in vitro and may be useful as a model of hematopoietic stem cell therapy for diseases of T cells, including acquired immunodeficiency syndrome.
Higher order parametric excitation modes for spaceborne quadrupole mass spectrometers (2011)

This paper describes a technique to significantly improve upon the mass peak shape and mass resolution of spaceborne quadrupole mass spectrometers (QMSs) through higher order auxiliary excitation of the quadrupole field. Using a novel multiresonant tank circuit, additional frequency components can be used to drive modulating voltages on the quadrupole rods in a practical manner, suitable for both improved commercial applications and spaceflight instruments. Auxiliary excitation at frequencies near twice that of the fundamental quadrupole RF frequency provides the advantages of previously studied parametric excitation techniques, but with the added benefit of increased sensed excitation amplitude dynamic range and the ability to operate voltage scan lines through the center of upper stability islands. Using a field programmable gate array, the amplitudes and frequencies of all QMS signals are digitally generated and managed, providing a robust and stable voltage control system. These techniques are experimentally verified through an interface with a commercial Pfeiffer QMG422 quadrupole rod system. When operating through the center of a stability island formed from higher order auxiliary excitation, approximately 50% and 400% improvements in 1% mass resolution and peak stability were measured, respectively, when compared with traditional QMS operation. Although tested with a circular rod system, the presented techniques have the potential to improve the performance of both circular and hyperbolic rod geometry QMS sensors.
Composite signature based watermarking for fingerprint authentication (2005)

Digital watermarking is a technology to hide information in digital media. We extend the digital watermarking technique Phasemark™, originally developed solely for image authentication, to biometrics to assist in forensic analysis. Using a signature extracted from the Fourier phase of the original image, we hide an encoded signature back into the original image forming a watermarked image. The hiding occurs in the Fourier transform frequency domain. The detection process computes the Fourier transform of the watermarked images, extracts the embedded signature and then correlates it with a calculated signature. Various correlation metrics determine the identity degree of biometric authentication. We show how a composite filter can be used in conjunction with Phasemark™ for robust authentication of fingerprints.
Predicting episodes of atrial fibrillation using RR-intervals and ectopic beats (2017)

Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with an increased risk of stroke and mortality. Research into the prediction of AF onset has been motivated by the necessity to develop better pacing therapy to reduce the incidence of AF and maintain the heart's normal sinus rhythm. In this paper, we address a similar problem to that posed in the Computers in Cardiology Challenge 2001, but develop patient specific models to distinguish between epochs of ECG located far away from AF rhythms and those located just prior to the onset of those episodes. Our approach is validated using a publicly available dataset.
A Novel Fluid Structure Interaction-EHD Model and Optimization Procedure for an Asymmetrical Axially Balanced External Gear Machine (2014)

AbstractThis article presents a novel fluid structure interaction (FSI) model for lateral lubricating interfaces in an asymmetrically balanced external gear pump. Due to the asymmetry in the geometry of the floating lateral bushes responsible for sealing the displacement chambers in such machines, the lubricating interfaces on either side of the gears have been modeled as distinct but coupled lubricating films. An elastohydrodynamic (EHD) lubrication regime was modeled in all simulations and film thickness predictions for both lubricating interfaces have been achieved. The novel FSI model for the asymmetric lateral gaps is then used in an automatic optimization procedure to design the optimal axial balance in the reference external gear machine (EGM). The optimal axial balance is achieved by determining the optimal balance area on the lateral bush by considering specific design variables associated with it. The procedure aims to find the best feasible design solution that minimizes the total power losses in the lubricating interfaces while also minimizing the nonuniformities in the orientation of these gaps between two significant operating conditions of the EGM. The developed procedure highlights the potential to virtually design the axial balance in EGMs—which represent a key design aspect of pressure compensated EGM—by using an advanced FSI-EHD model.KEY WORDS: Gear Hydraulic PumpsPressure Compensated PumpsLubricating GapsEHL NomenclatureA=Area (m2)d=Wheelbase of the pump (m)F=Force (N)h=Film thickness (m)M=Moment (N-m)O=Order of magnitudeP=Power loss (Nm/s)p=Pressure (Pa)Q=Volumetric flow rate (m3)R=Outer radius of gears (m)T=Torque (Nm)v=Cartesian velocity vector (m/s)X=Cartesian X coordinateY=Cartesian Y coordinateλ, ξ=Lame's coefficientsμ=Kinematic viscosity of working fluid (Pa-s)ρ=Density (kg/m3)τzx=Shear stress in XY plane in the X direction (N/m2)ω=Angular velocity (rad/s)Subscriptsavg=AverageBlk=Bearing blockb=Bottom surfaceDn=Driven gearDr=Driver gear=Losses due to leakages=Losses due to fluid shearmax=Maximummin=MinimumPis=Balance pistonRef=ReferenceRes=Resultantt=Top surfaceUD=Undeformed
A low-power multi-bit /spl Sigma//spl Delta/ modulator in 90-nm digital CMOS without DEM (2005)

Multi-bit sigma-delta modulators are widely used in analog-to-digital conversion especially in the modern deep-submicron CMOS process. As the quantizer resolution of /spl Sigma//spl Delta/ modulators increases, the SNR performance improves. However, the feedback DAC has to maintain high linearity. The general practice to achieve that is to use dynamic element matching (DEM). The methodology proposed in this paper will greatly reduce the complexity or even avoid usage of DEM for multi-bit /spl Sigma//spl Delta/ modulators. The proposed methodology-truncation error shaping and cancellation-reduces the feedback DAC levels for multi-bit quantizers. A prototype was designed in a standard CMOS 90-nm process to demonstrate the proposed methodologies. It achieved targeted performance without DEM at low power consumption with small silicon area.
Active material based active sealing technology: Part 1. Active seal requirements vs. active material actuator properties (2010)

Current seals used for vehicle closures/swing panels are essentially flexible, frequently hollow structures whose designs are constrained by numerous requirements, many of them competing, including door closing effort (both air bind and seal compression), sound isolation, prevention of water leaks, and accommodation of variations in vehicle build. This paper documents the first portion of a collaborative research study/exploration of the feasibility of and approaches for using active materials with shape and stiffness changing attributes to produce active seal technologies, seals with improved performance. An important design advantage of an active material approach compared to previous active seal technologies is the distribution of active material regions throughout the seal length, which would enable continued active function even with localized failure. Included as a major focus of this study was the assessment of polymeric active materials because of their potential ease of integration into the current seal manufacturing process. In Part 1 of this study, which is documented in this paper, potential materials were evaluated in terms of their cost, activation mechanisms, and mechanical and actuation properties. Based on these properties, simple designs were proposed and utilized to help determine which materials are best suited for active seals. Shape memory alloys (SMA) and electroactive polymers (EAP) were judged to be the most promising.
Electrical Resistance Tomography for Steam Injection Monitoring and Process Control (1995)

We used electrical resistance tomography (ERT) to map, in near-real time, the subsurface effects of two in situ thermal treatment processes: steam injection and ohmic heating. These effects were monitored at a gasoline-contaminated site as part of a demonstration of an environmental restoration process known as Dynamic Underground Stripping. ERT uses a dipole-dipole measurement technique to measure the bulk electrical resistivity distribution in the soil mass. We detected the effects of steam invasion and ohmic heating by mapping spatial and temporal changes in soil resistivity. During steam injection, there sistivity changes in the saturated zone were caused primarily by increases in pore water and soil temperatures, and to a lesser extent by changes in liquid saturation and groundwater electrical conductivity. During ohmic heating, the resistivity changes were caused by temperature increases, liquid saturation changes, and changes in the groundwater's electrical conductivity. This test demonstrated that ERT tomographs, used in combination with other data such as temperature, can be used reliably to monitor and control the progress of subsurface thermal remediation.