gebhart/patrepeval huggingface dataset:
Composite Membranes for Medium-Temperature PEM Fuel Cells (2003)

▪ Abstract The main obstacles to greater commercialization of polymer electrolyte fuel cells are mostly related to the low-proton conductivity at low-relative humidity of the known ionomeric membranes, to their high methanol permeability and poor mechanical properties above ∼130°C. A possible solution for these problems has been found in the development of composite membranes, where particles of suitable fillers are dispersed in the ionomer matrix. The preparation methods for obtaining composite membranes are described, and recent work dealing with composite ionomeric membranes containing silica, heteropolyacids, layered metal phosphates, and phosphonates is reviewed. Finally, new strategies for the preparation of nano-composite membranes and for the filling of porous polymeric membranes with highly conductive zirconium phosphonates are described. The expected influence of size and orientation of these particles on membrane properties, such as conductivity and permeability to methanol, is also discussed.
Statistical approach to color rendition properties of solid state light sources (2011)

Versatile spectral power distribution of solid-state light sources offers vast possibilities in color rendition engineering. The optimization of such sources requires the development and psychophysical validation of an advanced metric for assessing their color quality. Here we report on the application and validation of the recently introduced statistical approach to color quality of illumination. This new metric uses the computational grouping of a large number of test color samples depending on the magnitude and direction of color-shift vectors in respect of just perceived differences of chromaticity and luminance. This approach introduces single-format statistical color rendition indices, such as Color Fidelity Index, Color Saturation Index and Color Dulling Index, which are the percentages of test color samples with particular behavior of the color-shift vectors. The new metric has been used for the classification of practical phosphor conversion white light-emitting diodes (LEDs) and polychromatic LED clusters into several distinct categories, such as high-fidelity, color saturating, and color dulling light sources. We also report on the development of the tetrachromatic light source with dynamically tailored color rendition properties and using this source for the psychophysical validation of the statistical metric and finding subjective preferences to the color quality of lighting.
Retinotopic to Spatiotopic Mapping in Blind Patients Implanted With the Argus II Retinal Prosthesis (2017)

The brain accurately maps the artificial vision induced by a retinal prosthesis based on instantaneous gaze position. Remapping based on eye position is feasible and will increase visual stability in prosthetic vision.
Efficient Induction and Expansion of Human Alloantigen-Specific CD8 Regulatory T Cells from Naive Precursors by CD40-Activated B Cells (2009)

Although recent studies have focused on CD4(+) regulatory T cells (Treg), CD8(+) Treg have also been reported to play important roles in the induction and maintenance of immune tolerance. Adoptive transfer of CD8(+) Treg in rodents or induction of CD8(+) Treg in humans can prevent or treat allograft rejection and autoimmune diseases. However, no approaches have been reported for the generation of human Ag-specific CD8(+) Treg at a practical scale for clinical use. Here, we found that two novel CD8(+) T cell subsets with different levels of CD8 surface expression, CD8(high) and CD8(low), could be induced from naive CD8(+) precursors in vitro by allogeneic CD40-activated B cells, whereas only CD8(high) T cells were alloantigen-specific Treg with relatively poor alloantigen-specific cytotoxicity. Importantly, alloantigen-specific CD8(high) Treg could be induced and expanded from naive CD8(+)CD25(-) T cells at a large scale after 3 wk of culture without exogenous cytokines. These induced alloantigen-specific Treg were CD45RO(+) and CCR7(-) memory cells, and they expressed Foxp3, CD25, CD27, CD28, and CD62L. The induction and expansion of CD8(high) Treg by CD40-activated B cells were dependent on endogenously expressed IFN-gamma, IL-2, IL-4, and CTLA-4. This approach may facilitate the clinical application of CD8(+) Treg-based immunotherapy in transplantation and autoimmune diseases.
Blind timing and channel estimation for UWB multi-user ad hoc access (2005)

One of the major challenges at the physical layer of an ultrawideband (UWB) network is the accuracy and speed of the synchronization and channel estimation tasks. Especially in ad hoc multiaccess scenarios, acquiring timing and channel information blindly is instrumental for user separation and bandwidth efficient demodulation. Relying on intermittently transmitted asymmetric pulse-amplitude modulated (PAM) signals, we derive novel blind timing and channel estimators for UWB point-to-point and multiaccess communication links for use in ad hoc networks. Both intersymbol interference (ISI)-free as well as ISI channels are considered. Comparisons are provided and performance of the resultant algorithms is evaluated analytically and with bit-error rate (BER) simulations.
A Contrarotating Propeller Design for a High Speed Patrol Boat with Pod Propulsion. (1995)

Abstract : A contrarotating (CR) propeller design with a tractor pod for a high speed patrol boat is addressed. In the current arrangement, a CR propeller is placed at the forward end of a pod which is aligned with the local inflow. The powering and cavitation experiments show the performance prediction agree well with measurements. Compared to the existing controllable pitch propeller with shaft and strut configuration, the pod-mounted CR propeller show a 28% reduction in power consumption at design speed with a 7 knot improvement in cavitation inception speed. At full power, a larger pod is required, which will reduce the gain in power consumption.
Dual-Injection Airlift Pumps: An Enhanced Performance (2012)

Abstract The airlift pump is a device for raising liquids or mixtures of liquids and solids through a vertical pipe, which partially submerged in the liquid, by using compressed air introduced at the lower end of the pipe. Airlift pumps are finding increasing use where reliability and low maintenance are required, and when compressed air or gas are readily available as an energy source for water and oil pumping applications. In comparison with other conventional pumps, the particular merit of the airlift pump is the mechanical simplicity. However, the main disadvantage of these pumps is their low efficiency especially at low liquid submergence ratio. In the present study, a dual injector is designed in order to increase the pump efficiency. The new injector is manufactured and tested for different water submergence ratios. The efficiency of the new design is found to be at least 30% higher than that of a conventional design. A proposed model for the analysis of the pump performance is presented and validated using the obtained experimental data. The model prediction of the pump performance is found to be in the range of ±15% of the obtained experimental data. Keywords: airlift pumpsannular injectiondual-injectionmulti-injectiontwo-phase flow Acknowledgments The authors would like to thank Hossam Al-Ghofaily and Rakan Al-Ajmi for taking the measurements and Romeo Agua for manufacturing the injector. The funding support of the Deanship of Scientific Research (DSR) at King Fahd University of Petroleum & Minerals (KFUPM) under Project No. IN111023 is gratefully acknowledged.
Free-water imaging in Parkinson’s disease and atypical parkinsonism (2015)

Conventional single tensor diffusion analysis models have provided mixed findings in the substantia nigra of Parkinson's disease, but recent work using a bi-tensor analysis model has shown more promising results. Using a bi-tensor model, free-water values were found to be increased in the posterior substantia nigra of Parkinson's disease compared with controls at a single site and in a multi-site cohort. Further, free-water increased longitudinally over 1 year in the posterior substantia nigra of Parkinson's disease. Here, we test the hypothesis that other parkinsonian disorders such as multiple system atrophy and progressive supranuclear palsy have elevated free-water in the substantia nigra. Equally important, however, is whether the bi-tensor diffusion model is able to detect alterations in other brain regions beyond the substantia nigra in Parkinson's disease, multiple system atrophy, and progressive supranuclear palsy and to accurately distinguish between these diseases. Free-water and free-water-corrected fractional anisotropy maps were compared across 72 individuals in the basal ganglia, midbrain, thalamus, dentate nucleus, cerebellar peduncles, cerebellar vermis and lobules V and VI, and corpus callosum. Compared with controls, free-water was increased in the anterior and posterior substantia nigra of Parkinson's disease, multiple system atrophy, and progressive supranuclear palsy. Despite no other changes in Parkinson's disease, we observed elevated free-water in all regions except the dentate nucleus, subthalamic nucleus, and corpus callosum of multiple system atrophy, and in all regions examined for progressive supranuclear palsy. Compared with controls, free-water-corrected fractional anisotropy values were increased for multiple system atrophy in the putamen and caudate, and increased for progressive supranuclear palsy in the putamen, caudate, thalamus, and vermis, and decreased in the superior cerebellar peduncle and corpus callosum. For all disease group comparisons, the support vector machine 10-fold cross-validation area under the curve was between 0.93-1.00 and there was high sensitivity and specificity. The regions and diffusion measures selected by the model varied across comparisons and are consistent with pathological studies. In conclusion, the current study used a novel bi-tensor diffusion analysis model to indicate that all forms of parkinsonism had elevated free-water in the substantia nigra. Beyond the substantia nigra, both multiple system atrophy and progressive supranuclear palsy, but not Parkinson's disease, showed a broad network of elevated free-water and altered free-water corrected fractional anisotropy that included the basal ganglia, thalamus, and cerebellum. These findings may be helpful in the differential diagnosis of parkinsonian disorders, and thereby facilitate the development and assessment of targeted therapies.
Slit-enabled linear-array photoacoustic tomography with near isotropic spatial resolution in three dimensions (2017)

Slit-enabled photoacoustic tomography (PAT) is a newly developed technique that improves the elevation resolution and signal to noise ratio of a linear array. The slit, placed along the transducer array focus, forms an array of virtual detectors with high receiving angle, which subsequently allows for three dimensional (3D) imaging with near-isotropic spatial resolution. Our development addressed the long-standing issue of high quality 3D imaging with a linear array and will have broad applications in preclinical and clinical imaging. This study presented the principle of slit-PAT and demonstrated its efficiency in phantom, animal, and human experiments.
A series array of microliter-sized microbial fuel cell (2011)

We report an array of three microliter-sized microbial fuel cells (MFC) that can produce 100 μW. Individual MFCs were integrated on two sandwiched glass slides, and had two 50 μL-sized chambers each (Geobactor sp. in the anode, ferricyanide in the cathode chambers, respectively) separated by a cation exchange membrane (CEM). The three MFCs were formed in a series array to produce 1.8 V at the maximum power delivery of 100 μW (power density of 33 μW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ). The 100 μW total power and 33 μW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> power density are approximately ten and three times higher, respectively, than the maximum values of previously reported microliter-sized MFCs.
Magnitude and spatial orientation of the hydrophobic moments of multi-domain proteins (2006)

The distributions of residue hydrophobicity for individual domains as well as for the aggregates of domains on a single chain have been found to exhibit well-defined second-order hydrophobic moment profiles. This indicates that most of the domains do fold into a stable entity with a core composed predominantly of hydrophobic residues as well as a prevalence of hydrophobic residues at the interface between domains. A simple scoring function based upon the relative hydrophobic moment dipole orientations shows that 80% of the dipoles of adjacent domains point to each other, highlighting hydrophobic residue prevalence at the domain interfaces.
Room-temperature soldering with nanostructured foils (2003)

Self-propagating formation reactions in nanostructured multilayer foils provide rapid bursts of heat and can act as local heat sources to melt solder layers and join materials. This letter describes the room-temperature soldering of stainless steel specimens using freestanding, nanostructured Al/Ni foils. The products, heats, and velocities of the reactions are described, and the microstructure and the mechanical properties of the resulting joints are characterized. A tensile shear strength of 48 MPa was measured for the reactive foil joints, compared to 38 MPa for conventional joints. Both numerical predictions and infrared measurements show limited heat exposure to the components during reactive joining.
Structure and Mechanism of Micropump Using Thermoresponsive Polymer Actuator. (1992)

This paper deals with a kind of micromachine based on a polymer gel actuator system. The polymer actuator has many merits in comparison with other actuators. ( 1 ) It is flexible because it is a polymer material. ( 2 ) It is light in weight. ( 3 ) It is easy to make into an arbitrary shape. Among the polymer gel actuators, we propose a micropump using a thermoresponsive polymer gel. This micropump consists of two one-way valves which make use of a high-water-absorbing polymer gel as a blocking ball. The overall size of this micropump prototype is 8 mm in diameter and 14.5 mm in length. Its weight is 3.2 g. A polymer gel actuator is constituted of the poly (vinyl methyl ether) static polymer (PVME). The mechanism of this micropump is as follows. ( 1 ) By heating the PVME, the gel shrinks. Then the volume of the pump chamber increases, resulting in the inflow of liquid from the inlet to the chamber. ( 2 ) By cooling the PVME, the gel swells in the water. Then the volume of the pump chamber decreases resulting the liquid flow the chamber to the outlet. ( 3 ) By repeating the heating and cooling processes, the micropump provides liquid flow from the inlet to the outlet. The micropump was tested, replacing heating by a nichrome wire with electric current, and showed satisfactory responses.
Real-time FPGA transmitter and receiver for coherent optical OFDM (2014)

We demonstrate a real-time FPGA implementation of coherent optical OFDM transmitter and receiver. It is implemented using two 2.5 GS/s DACs and one FPGA for transmitter, two ADCs and one FPGA for receiver, and FPGA based real-time digital signal processing for coherent optical OFDM transmission.
Synthesis of Biocompatible Liquid Crystal Elastomer Foams as Cell Scaffolds for 3D Spatial Cell Cultures (2017)

Here, we present a step-by-step preparation of a 3D, biodegradable, foam-like cell scaffold. These scaffolds were prepared by cross-linking star block co-polymers featuring cholesterol units as side-chain pendant groups, resulting in smectic-A (SmA) liquid crystal elastomers (LCEs). Foam-like scaffolds, prepared using metal templates, feature interconnected microchannels, making them suitable as 3D cell culture scaffolds. The combined properties of the regular structure of the metal foam and of the elastomer result in a 3D cell scaffold that promotes not only higher cell proliferation compared to conventional porous templated films, but also better management of mass transport (i.e., nutrients, gases, waste, etc.). The nature of the metal template allows for the easy manipulation of foam shapes (i.e., rolls or films) and for the preparation of scaffolds of different pore sizes for different cell studies while preserving the interconnected porous nature of the template. The etching process does not affect the chemistry of the elastomers, preserving their biocompatible and biodegradable nature. We show that these smectic LCEs, when grown for extensive time periods, enable the study of clinically relevant and complex tissue constructs while promoting the growth and proliferation of cells.
<title>SERODS: a new medium for high-density optical data storage</title> (1998)

A new optical dada storage technology based on the surface- enhanced Raman scattering (SERS) effect has been developed for high-density optical memory and three-dimensional data storage. With the surface-enhanced Raman optical data storage (SERODS) technology, the molecular interactions between the optical layer molecules and the nanostructured metal substrate are modified by the writing laser, changing their SERS properties to encode information as bits. Since the SERS properties are extremely sensitive to molecular nano- environments, very small 'spectrochemical holes' approaching the diffraction limit can be produced for the writing process. The SERODS device uses a reading laser to induce the SERS emission of molecules on the disk and a photometric detector tuned to the frequency of the RAMAN spectrum to retrieve the stored information. The results illustrate that SERODS is capable of three-dimensional data storage and has the potential to achieve higher storage density than currently available optical data storage systems.
Resonance on the web (2009)

The Web is a dynamic, ever-changing collection of information accessed in a dynamic way. This paper explores the relationship between Web page content change (obtained from an hourly crawl of over 40K pages) and people's revisitation to those pages (collected via a large scale log analysis of 2.3M users). We identify the relationship, or resonance, between revisitation behavior and the amount and type of changes on those pages. By coupling our large scale log analysis with a complementary user study we explore the intent behind the revisitation behavior we observed. Using the notion of resonance to identify the likely content of interest, we describe a number of ways interaction with changing and revisited information can be better supported. We illustrate how understanding the association between change and revisitation might improve browser, crawler, and search engine design, and present a specific example of how knowledge of both can enable relevant content to be highlighted.
Development and characterization of an omni-directional photoacoustic point source for calibration of a staring 3D photoacoustic imaging system (2009)

Photoacoustic imaging is a modality which makes use of the contrast provided by optical imaging techniques and the spatial resolution and penetration depth similar to acoustic imaging modalities. We have developed a method for fast 3D photoacoustic imaging using a sparse hemispherical array of transducers. Such a system requires characterization of the transducer's response to an ideal point source in order to accurately reconstruct objects in the imaging volume. First, an attempt was made to design an ideal photoacoustic point source via a combination of liquids which would appropriately scatter and absorb the light such that a spherical distribution was achieved. Methylene blue (MB(+)) was used as the primary optical absorber while Intralipid (IL) was used as the liquid responsible for the optical scatter. A multitude of combinations were tested and the signal uniformity was characterized. The combination of 200 microM MB(+) and 0.09% IL was found to produce the most uniform signal over the range of transducers in the hemispherical array. The liquid source was then characterized over a broader range of azimuthal and zenith angles where it was shown the azimuthal consistency was much greater than the stability seen in different zenith elevations. The source was then used in a calibration scan for an imaging volume of 40 x 40 x 40 mm(3). At 216 points evenly spaced in the imaging volume, parameters were recorded for signal amplitude, width, and time-of-flight. These calibration parameters could then be applied to an iterative reconstruction algorithm in an attempt to more accurately produce images.
Extending multi‐level STT‐MRAM cell lifetime by minimising two‐step and hard state transitions in hot bits (2017)

Shifting market trends towards mobile, Internet of things, and data‐centric applications create opportunities for emerging low‐power non‐volatile memories. The attractive features of spin‐torque‐transfer magnetic‐RAM (STT‐MRAM) make it a promising candidate for future on‐chip cache memory. Two‐bit multiple‐level cell (MLC) STT‐MRAMs suffer from higher write energy, performance overhead, and lower cell endurance when compared with single‐level counterpart. These unwanted effects are mainly due to write operations known as two‐step (TT) and hard transitions (HT). Here, the authors offer a solution to tackle write energy problem in MLC STT‐MRAM by minimising the number of TT and HT transitions. By analysing real applications, it was observed that specific locations within a cache block undergo much more TT and HT transitions resulting in hot locations when compared with other ones (cold locations). These hot locations are more detrimental to the lifetime and reliability of MRAM device. In this work, the authors propose a simple and intuitive dynamic encoding scheme that eliminates all TT and HT at hot locations, hence reducing energy consumption and improving MLC STT‐MRAM lifetime. Results on PARSEC benchmarks demonstrate the effectiveness and scalability of the proposed approach to potentially prolong MLC STT‐MRAM lifetime.
Airborne wind profiling with the data acquisition and processing system for a pulsed 2-micron coherent doppler lidar system (2012)

A pulsed 2-micron coherent Doppler lidar system at NASA Langley Research Center in Virginia flew on the NASA's DC-8 aircraft during the NASA Genesis and Rapid Intensification Processes (GRIP) during the summer of 2010. The participation was part of the project Doppler Aerosol Wind Lidar (DAWN) Air. Selected results of airborne wind profiling are presented and compared with the dropsonde data for verification purposes. Panoramic presentations of different wind parameters over a nominal observation time span are also presented for selected GRIP data sets. The real-time data acquisition and analysis software that was employed during the GRIP campaign is introduced with its unique features.