gebhart/patrepeval huggingface dataset:
New Cu-Cl Thermochemical Cycle for Hydrogen Production with Reduced Excess Steam Requirements (2009)

Abstract The Cu-Cl (copper–chlorine) thermochemical cycles for hydrogen production are leading examples of water-splitting methods. In this article, the heat requirements of different types of Cu-Cl cycles with various numbers of steps are analyzed, and their thermal design features are discussed in terms of water requirements, heat quantity, and heat grade. A challenge arises from the excess steam quantity requirement in the hydrolysis of CuCl2. To address this challenge, a new type of Cu-Cl cycle is proposed in this article. It is found that the steam requirement can decrease by up to ten times, compared with conventional Cu-Cl cycles, and the heat grade of the hydrolysis step in the new cycle is significantly lowered from 375°C to 150°C. The engineering challenges of the new cycle are also discussed in the article. Keywords: Copper-chlorine cycleHydrogen productionThermochemical water splitting ACKNOWLEDGMENTS Financial support from AECL (Atomic Energy of Canada Limited) and OREF (Ontario Research Excellence Fund) is gratefully acknowledged.
Application of ac tomography to crack identification (2007)

The depth of penetration of alternating currents in conductors depends on their frequency and material properties. A tomographiclike technique was proposed, in which the frequency is systematically varied to detect and size flaws (emerging and hidden) in electrical conductors, based on an analysis of the skin effect [Saguy and Rittel, Appl. Phys. Lett. 89, 094107 (2006); 87, 084103 (2005)]. Initial results were reported for notched specimens [Saguy and Rittel, NDT & E Int. 40, 505 (2007)] This letter presents experimental results on the detection of actual sharp fatigue cracks, differing from notches in terms of sharpness and partial conduction through the crack flanks. The results show that hidden cracks with arbitrary crack-front shape can be accurately identified.
Negative Resistance Values in Locally Resolved Impedance Spectra of Polymer Electrolyte Fuel Cells (2009)

This work demonstrates that the appearance of negative resistance values in locally resolved impedance spectra of PEFCs is, in general, a direct consequence of down the channel inhomogeneities due to changing concentration of oxidant, fuel or water along the flow channels. It is shown that the local polarization resistance becomes negative, as the local change in i)concentration polarization and/or ii)ohmic loss exceeds the total perturbation voltage amplitude at low frequencies. This forces the local cell current to decrease despite a higher total cell polarization. For the first time, this effect is shown here as a consequence of fuel and water depletion along the flow channels of a linear PEFC. Based on our earlier experimental results for the effect of oxygen depletion in H2/air PEFCs, we present a pseudo 2D transient model to further illustrate the impact of mass transport limitations along the cathode flow channels on locally resolved impedance response.
A Reliable Soil Moisture Sensing Methodology for Agricultural Irrigation (2017)

Agricultural irrigation accounts for two-thirds of global fresh water use and plays a pivotal role in addressing the challenge of water shortage. Soil moisture sensors can improve the water use efficiency of irrigation and this work is a study on sensor deployment and fault detection in the context of agricultural irrigation. Previous works are mostly oriented toward general applications and focused on optimizing complicated sensor networks. In agricultural irrigation, the sensor network is relatively simple, while the expectation to system reliability is quite high. In this work, a reliability-driven soil moisture sensing methodology is developed and discussed. It includes a genetic algorithm based optimization technique and a fault detection technique. Simulations are performed to compare the proposed methodology with previous works. The results indicate that the proposed methodology considerably improves system reliability in term of mean time to failure.
Retinoic acid inhibits induction of c-Jun protein by ultraviolet radiation that occurs subsequent to activation of mitogen-activated protein kinase pathways in human skin in vivo. (1998)

Human skin is exposed daily to solar ultraviolet (UV) radiation. UV induces the matrix metalloproteinases collagenase, 92-kD gelatinase, and stromelysin, which degrade skin connective tissue and may contribute to premature skin aging (photoaging). Pretreatment of skin with all-trans retinoic acid (tRA) inhibits UV induction of matrix metalloproteinases. We investigated upstream signal transduction pathways and the mechanism of tRA inhibition of UV induction of matrix metalloproteinases in human skin in vivo. Exposure of human skin in vivo to low doses of UV activated EGF receptors, the GTP-binding regulatory protein p21Ras, and stimulated mitogen-activated protein (MAP) kinases, extracellular signal-regulated kinase (ERK), c-Jun amino-terminal kinase (JNK), and p38. Both JNK and p38 phosphorylated, and thereby activated transcription factors c-Jun and activating transcription factor 2 (ATF-2), which bound to the c-Jun promoter and upregulated c-Jun gene expression. Elevated c-Jun, in association with constitutively expressed c-Fos, formed increased levels of transcription factor activator protein (AP) 1, which is required for transcription of matrix metalloproteinases. Pretreatment of human skin with tRA inhibited UV induction of c-Jun protein and, consequently, AP-1. c-Jun protein inhibition occurred via a posttranscriptional mechanism, since tRA did not inhibit UV induction of c-Jun mRNA. These data demonstrate, for the first time, activation of MAP kinase pathways in humans in vivo, and reveal a novel posttranscriptional mechanism by which tRA antagonizes UV activation of AP-1 by inhibiting c-Jun protein induction. Inhibition of c-Jun induction likely contributes to the previously reported prevention by tRA of UV induction of AP-1-regulated matrix-degrading metalloproteinases in human skin.
Photooxidative degradation of graphene‐reinforced high‐density polyethylene nanocomposites (2018)

ABSTRACT Natural weathering of high‐density polyethylene (HDPE) and its graphene nanocomposites was studied. The nanocomposites, prepared by in situ polymerization of ethylene, were exposed to the natural environment for 30, 60, and 90 days. The effects of weathering on the crystallinity, melting temperature, and lamellar thickness distribution were studied using differential scanning calorimetry. The changes in chain microstructure and molecular weight were determined by crystallization analysis fractionation and gel permeation chromatography, respectively. The effects of weathering on the dynamic mechanical properties and the morphology of the nanocomposite were also determined. The parent HDPE suffered severe degradation as expected. However, graphene‐reinforced HDPE nanocomposites show resistance to degradation. The changes in the crystallinity, lamellar thickness, molecular weight, and dynamic mechanical properties of graphene nanocomposites were less pronounced as compared to the parent HDPE. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47030.
An inverse geometry CT system with stationary source arrays (2011)

Traditional CT systems face a tradeoff between temporal resolution, volumetric coverage and cone beam artifacts and also have limited ability to customize the distribution of incident x-rays to the imaging task. Inverse geometry CT (IGCT) can overcome some of these limitations by placing a small detector opposite a large, rotating scanned source array. It is difficult to quickly rotate this source array to achieve rapid imaging, so we propose using stationary source arrays instead and investigate the feasibility of such a system. We anticipate that distinct source arrays will need to be physically separated, creating gaps in the sinogram. Symmetry can be used to fill the missing rays except those connecting gaps. With three source arrays, a large triangular field of view emerges. As the small detector orbits the patient, each source spot must be energized at multiple specifically designed times to ensure adequate sampling. A timing scheme is proposed that avoids timing clashes, efficiently uses the detector, and allows for simple collimation. The two-dimensional MTF, noise characteristics, and artifact levels are all found to be comparable to parallel-beam systems. A complete, 100 millisecond volumetric scan may be feasible.
Improved Reconstruction of DPCM-Coded Pictures (1982)

A new scheme for the reconstruction of DPCM-coded signals is presented. In this scheme, instead of assigning one representative level to the prediction error whenever it is in a range determined by the decision levels of a DPCM quantizer, surrounding local picture structure is used to improve the reconstruction. No extra transmission is required. Mean-absolute-reconstruction error is decreased by over 20 percent, and the picture quality is significantly improved in flat, as well as high, detailed areas of still pictures and sequences of pictures containing motion.
Integrated photoacoustic and fluorescence confocal microscopy (2011)

Optical-resolution photoacoustic microscopy has demonstrated utility in imaging and characterizing microvasculature networks in vivo. This work presents a novel imaging system that integrates optical-resolution photoacoustic microscopy and fluorescence confocal microscopy for simultaneous photoacoustic and fluorescence imaging. The integrated system can acquire intrinsically registered photoacoustic and fluorescence images in a single scan. Capable of providing micrometer scale microscopic imaging of both optical absorption and fluorescence contrasts, the system demonstrates in vivo imaging of oxygen saturation and oxygen partial pressure in mouse ears.
Design, implementation, and evaluation of highly available distributed call processing systems (2002)

This paper presents the design of a highly available distributed call processing system and its implementation on a local area network of commercial, off-the-shelf workstations. A major challenge of using off-the-shelf components is meeting the strict performance and availability requirements in place for existing public telecommunications systems in a cost-effective manner. Traditional checkpointing and message logging schemes for general distributed applications are not directly applicable since call processing applications built using these schemes suffer from high failure-free overhead and long recovery delays. We propose an application-level fault-tolerance scheme that takes advantage of general properties of distributed call processing systems to avoid message logging and to limit checkpointing overhead. The proposed scheme, applied to a call processing system for wireless networks, shows average call setup latencies of 180 ms, failover times of less than three seconds, and recovery times of less than seventeen seconds. System availability is estimated to be 0.99995. The results indicate that using our proposed scheme meets the above challenge.
Nonlinearities, SHG, and poling in silica fibers (1996)

Summary form only given. Progress in establishing a large second-order nonlinearity in silica fibers is reviewed. A second order nonlinearity has been induced in germanosilicate fibers by poling the fiber with a large applied electric field and either an elevated temperature [100 - 200 C] or UV irradiation [193 nm or 248 nm]. Nonlinearities approaching that of LiNbO/sub 3/ have been reported. Once the nonlinearity is established, the field can be removed leaving a permanent effect.
A framework for personalization of coronary flow computations during rest and hyperemia (2012)

We introduce a Computational Fluid Dynamics (CFD) based method for performing patient-specific coronary hemodynamic computations under two conditions: at rest and during drug-induced hyperemia. The proposed method is based on a novel estimation procedure for determining the boundary conditions from non-invasively acquired patient data at rest. A multi-variable feedback control framework ensures that the computed mean arterial pressure and the flow distribution matches the estimated values for an individual patient during the rest state. The boundary conditions at hyperemia are derived from the respective rest-state values via a transfer function that models the vasodilation phenomenon. Simulations are performed on a coronary tree where a 65% diameter stenosis is introduced in the left anterior descending (LAD) artery, with the boundary conditions estimated using the proposed method. The results demonstrate that the estimation of the hyperemic resistances is crucial in order to obtain accurate values for pressure and flow rates. Results from an exhaustive sensitivity analysis have been presented for analyzing the variability of trans-stenotic pressure drop and Fractional Flow Reserve (FFR) values with respect to various measurements and assumptions.
Words recognition using associative memory (2002)

Introduces the application of an analog associative memory chip to word recognition, which is a fundamental topic of the text recognition process. The word recognition method takes advantage of a statistical evaluation of the behavior of the optical character recognition system preceding it. That statistical information leads to the creation of a coding that is used to store a lexicon of the most used words in the chip. An input pattern is matched against the full database of the associative memory, and a set of closest patterns is returned. The precision reached by this operation ranges from 93% to 99%. These encouraging results demonstrate the general aptitude of the chip to solve classes of problems that need to use an associative memory.
Automatic detection of rib metastasis in chest CT volume data (2007)

We describe a system for the automatic detection of rib metastasis in thoracic CT volume. Rib metastasis manifest itself as alterations of bone intensities or shapes, and the detection of these alterations is the goal of the algorithm. According to the tubular shape of the rib structures, the detection is based on the construction of 2D cross-sections planes along the full lengths of each of the individual ribs. The set of planes is orthogonal to the rib centerline, with is extracted by a previously developed segmentation algorithm based on recursive tracing. On each of these planes, a 2D image is constructed by interpolation in the region of interest around the centerline intersection and the plane. From this image the cortical and trabecular bones are segmented separately. The appearance and geometric properties of the bone structures are analyzed and categorized according to a set of rules that summarize the possible variation types due to metastasis. The features extracted from the cross-sections along a short length of the centerline are jointly evaluated. A positive detection is accepted only if the alteration of shape and appearance is consistent with a number of consecutive cross-sections along the rib centerline.
Dynamic Multi-View Autostereoscopy (2019)

With advantages of motion parallax and viewing convenience, multi-view autostereoscopic displays have attracted increasing attention in recent years. It is obvious that increasing the number of views improves the quality of 3D images/videos and leads to better motion parallax. However, it requires huge amount of computing resources to generate large numbers of view images in real time. In principle, objects appearing near the screen plane have very small absolute disparity. It can use fewer views to present these objects for achieving the same level of motion parallax. The concept of dynamic multi-view autostereoscopy is to dynamically control the number of views to generate for the points in 3D space based on their disparity. Points with larger absolute disparity use more views, while points with smaller absolute disparity use fewer views. As a result, fewer computing resources are required for real-time generation of view images. Subjective assessments show that only slight degradation in 3D experience is resulted on its realization over 2D plus depth based multi-view autostereoscopic display. However, the amount of computation for generating view images can be reduced by about 44.3% when 3D scenes are divided into three spaces.
The Force Awakens: Illuminating the role of kynurenine in cancer progression and treatment. (2018)

Abstract Cancer is the second leading cause of death in the US and, despite progress in treatment options, there is a critical need for novel treatments that specifically target cancerous cells. Our immune system routinely identifies potential cancer cells and eliminates them without the need for clinical intervention. However, to evade immune clearance, many cancers elevate tryptophan catabolism in the tumor microenvironment (TME) by upregulating the enzymes indoleamine 2, 3-dioxygenase (IDO) or, alternatively, tryptophan 2, 3- dioxygenase (TDO). This results in greater tryptophan turnover, accumulation of IDO/TDO product, kynurenine (L-kyn), and immune suppression in the TME. Whether the resulting immunosuppression arises from tryptophan depletion or L-kyn accumulation remains highly controversial. This work aims to (1) clarify L-kyn’s effect on T-cells and (2) whether its depletion can relieve tumor burden. Exposing T cells to L-kyn in vitro results in gene expression changes consistent with regulatory T-cell generation and the suppression of naïve T-cell proliferation; establishing L-kyn as a key therapeutic target for depletion to relieve TME immune suppression. Using a pharmacologically optimized kynureninase (KynU) enzyme, we tested L-kyn depletion therapy in murine cancers. KynU administration potently inhibits tumor growth, reduces L-kyn concentration, and results in a significant increase in the infiltration and proliferation of polyfunctional T-lymphocytes. Our ongoing study of KynU’s efficacy and L-kyn’s in vitro effects will illuminate details of L-kyn’s elusive mechanism of action, resolving critical mechanisms of tumor tolerance while creating a more innovative and effective cancer treatment strategy.
Studies on the effect of human lys-plasminogen in a rat model of global cerebral ischemia. (1997)

Human lys-plasminogen and the corresponding formulation buffer were tested in a rat model of global cerebral ischemia (clamping of both carotid arteries, withdrawal of 5 ml blood for 30 min). The two main parameters, tested in different experimental set-ups, were 1. brain edema (water content) 23.5 h after reperfusion and 2. assessment of neurological deficits 24, 48 and 72 h after reperfusion. In some groups of animals of the first set-up, brains were examined histologically for microvascular fibrin deposits. In a separate group of animals the fibrinolytic plasma activity of rats treated with 500 CU/kg lys-plasminogen was studied. Concerning brain water content lys-plasminogen completely antagonized the formation of brain edema when given with 500 caseolytic Units (CU)/kg i.v. with blood reperfusion and was still effective when given 30 min later. 200 CU/kg i.v. given with blood reperfusion as well as 500 CU/kg i.v. given 60 min after blood reperfusion proved ineffective. In none of the brains investigated microvascular fibrin deposits were found. In experiments with assessment of neurological deficits, animals treated with 500 CU/kg lys-plasminogen i.v. showed almost no disabilities (like sham operated animals) when compared to ischemic (positive) controls which were rather severely handicapped. The formulation buffer of lys-plasminogen, tested in an equivalent volume, was without any effect in both set-ups. No fibrinolytic activity was found in plasma samples of rats up to 240 min after treatment with 500 CU/kg lys-plasminogen i.v. It is concluded from these experiments that human lys-plasminogen has a protective effect in rats against the sequelae of global cerebral ischemia which is not related to the well-known fibrinolytic potential but might be a separate quality.
Friends of an enemy (2010)

In this work we show that once a single peer-to-peer (P2P) bot is detected in a network, it may be possible to efficiently identify other members of the same botnet in the same network even before they exhibit any overtly malicious behavior. Detection is based on an analysis of connections made by the hosts in the network. It turns out that if bots select their peers randomly and independently (i.e. unstructured topology), any given pair of P2P bots in a network communicate with at least one mutual peer outside the network with a surprisingly high probability. This, along with the low probability of any other host communicating with this mutual peer, allows us to link local nodes within a P2P botnet together. We propose a simple method to identify potential members of an unstructured P2P botnet in a network starting from a known peer. We formulate the problem as a graph problem and mathematically analyze a solution using an iterative algorithm. The proposed scheme is simple and requires only flow records captured at network borders. We analyze the efficacy of the proposed scheme using real botnet data, including data obtained from both observing and crawling the Nugache botnet.
Efficient quarter-Joule KrF laser with corona preionization (1979)

Conventional KrF excimer lasers which are pumped by means of an avalanche discharge use the ultraviolet radiation generated by a series of spark discharges to preionize the discharge region in order to obtain a uniform discharge. This paper describes the design and operating characteristics of a KrF avalanche-discharge laser which uses a corona discharge to preionize the discharge region. Such a preionization technique, along with the unconventional use of Ne rather than He as the buffer gas, has enabled this laser to generate over <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\frac{1}/{4}</tex> J of output energy with an overall efficiency of 1.3 percent while operating at a pulse rate of 2 Hz. This same general technique has enabled us to generate 55 W of average power from a gas transport KrF laser operating at higher pulse rates.
Wide-field reflection phase microscope (2011)

Wide-field reflection phase microscopy is highly desired for depth-resolved measurement of cellular structures without the need for raster scanning. We report a low coherence reflection phase microscope based on time-domain optical coherence tomography and off-axis interferometry. The setup uniquely provides the desired angular shift to the reference beam for off-axis interferometry while promising equal path length across the whole reference beam. We show sub-nanometer path-length sensitivity of our instrument and demonstrate high-speed imaging of membrane fluctuations in eukaryotic cells.
Knife-edge scanning measurements of subwavelength focused light beams (1977)

This note describes a convenient working technique for measuring the minimum size focused spot formed by a lens system. The technique is routinely capable of measurement precision of better than ?lambda. The theory of knife-edge scanning is presented, and the relationship of the measured spot profile to the actual spot profile is shown to be relatively insensitive to the acceptance solid angle of the photodetector. Finally, some typical results of high resolution microscope objectives are presented.