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This article describes a process of fabricating highly porous paper from cellulosic fibers and carbon black (CB) with tunable conductivity. By embossing such paper, its porosity decreases while its conductivity increases. Tuning the porosity of composite paper alters the magnitude and trend of conductivity over a spectrum of concentrations of conductive particles. The largest increase in conductivity from 8.38 × 10-6 to 2.5 × 10-3 S/m by a factor of ∼300 occurred at a percolation threshold of 3.8 wt % (or 0.36 vol %) with the composite paper plastically compressed by 410 MPa, which caused a decrease of porosity from 88% to 42% on average. Our composite paper showed stable piezoresistive responses within a broad pressure range from 1 kPa up to 5.5 MPa for 800 cycles. The piezoresistive sensitivities of the composite paper were dependent on concentration and decreased with pressure. Composite paper with 7.5 wt % CB had sensitivities of -0.514 kPa-1 over applied pressures ranging from 1 to 50 kPa and -0.215 kPa-1 from 1 to 250 kPa. This piezoresistive paper with embossed patterns enabled touch sensing and detection of damage from darts and punches. Understanding the percolation behavior of three-phase composites (cellulosic fibers/conductive particles/air) and their response to damage, pressure, and processing conditions has the potential to enable scalable applications in prosthetics and robotics, haptic feedback, or structural health monitoring on expansive surfaces of buildings and vehicles.

Motivated by the need to interpret the results from a combined use of in vivo brain Magnetic Resonance Elastography (MRE) and Diffusion Tensor Imaging (DTI), we developed a computational framework to study the sensitivity of single-frequency MRE and DTI metrics to white matter microstructure and cell-level mechanical and diffusional properties. White matter was modeled as a triphasic unidirectional composite, consisting of parallel cylindrical inclusions (axons) surrounded by sheaths (myelin), and embedded in a matrix (glial cells plus extracellular matrix). Only 2D mechanics and diffusion in the transverse plane (perpendicular to the axon direction) was considered, and homogenized (effective) properties were derived for a periodic domain containing a single axon. The numerical solutions of the MRE problem were performed with ABAQUS and by employing a sophisticated boundary-conforming grid generation scheme. Based on the linear viscoelastic response to harmonic shear excitation and steady-state diffusion in the transverse plane, a systematic sensitivity analysis of MRE metrics (effective transverse shear storage and loss moduli) and DTI metric (effective radial diffusivity) was performed for a wide range of microstructural and intrinsic (phase-based) physical properties. The microstructural properties considered were fiber volume fraction, and the myelin sheath/axon diameter ratio. The MRE and DTI metrics are very sensitive to the fiber volume fraction, and the intrinsic viscoelastic moduli of the glial phase. The MRE metrics are nonlinear functions of the fiber volume fraction, but the effective diffusion coefficient varies linearly with it. Finally, the transverse metrics of both MRE and DTI are insensitive to the axon diameter in steady state. Our results are consistent with the limited anisotropic MRE and co-registered DTI measurements, mainly in the corpus callosum, available in the literature. We conclude that isotropic MRE and DTI constitutive models are good approximations for myelinated white matter in the transverse plane. The unidirectional composite model presented here is used for the first time to model harmonic shear stress under MRE-relevant frequency on the cell level. This model can be extended to 3D in order to inform the solution of the inverse problem in MRE, establish the biological basis of MRE metrics, and integrate MRE/DTI with other modalities towards increasing the specificity of neuroimaging.

The Primordial Inflation Polarization ExploreR (PIPER) is a balloon-borne instrument optimized to measure the polarization of the CMB at large angular scales. It will map 85% of the sky over a series of conventional balloon flights from the Northern and Southern hemispheres, measuring the B-mode polarization power spectrum over a range of multipoles from 2-300 covering both the reionization bump and the recombination peak, with sensitivity to measure the tensor-to-scalar ratio down to r = 0.007. PIPER will observe in four frequency bands centered at 200, 270, 350, and 600 GHz to characterize dust foregrounds. The instrument has background-limited sensitivity provided by fully cryogenic (1.7 K) optics focusing the sky signal onto kilo-pixel arrays of time-domain multiplexed Transition-Edge Sensor (TES) bolometers held at 100 mK. Polarization sensitivity and systematic control are provided by front-end Variable-delay Polarization Modulators (VPMs). PIPER had its engineering ight in October 2017 from Fort Sumner, New Mexico. This papers outlines the major components in the PIPER system discussing the conceptual design as well as specific choices made for PIPER. We also report on the results of the engineering flight, looking at the functionality of the payload systems, particularly VPM, as well as pointing out areas of improvement.

The Soft X-ray Spectrometer (SXS) instrument, one of several instruments on JAXA’s Astro-H mission, will observe diffuse X-ray sources with unparalleled spectral resolution using a microcalorimeter array operating at 50 mK. The array is cooled with a multi-stage Adiabatic Demagnetization Refrigerator mounted on a 40 l helium tank. The tank is at the center of a typical “shell in shell” cryostat, with the innermost shield cooled by a JT cryocooler, and successive outer shields cooled by stirling-cycle cryocoolers. To achieve a multi-year liquid helium lifetime and to avoid exceeding the limited capacity of the JT cooler, very strict requirements are placed on every source of heat leak into these surfaces from the higher temperature shields. However, each ADR stage draws a maximum of 2 A, and the Wiedemann–Franz Law precludes even an optimized set of normal-metal leads capable of such high current from achieving the required low thermal conductance. Instead, a set of lead assemblies have been developed based on narrow high temperature superconductor (HTS) tapes derived from commercially available coated conductors. Although the HTS tapes are flexible and have high tensile strength, they are extremely sensitive to damage through a number of mechanisms. A robust set of assemblies have been developed that provide mechanical support to the tapes, provide appropriate interfaces at either end, and yet still meet the challenging thermal requirements. An Engineering Model (EM) set of HTS lead assemblies have survived environmental testing, both as individual units and as part of the EM cryostat, and have performed without problem in recent operation of the EM instrument. The Flight Model (FM) HTS lead assemblies are currently nearing completion.

The Primordial Inflation Polarization Explorer (PIPER) is a balloon-borne telescope mission to search for inflationary gravitational waves from the early universe. PIPER employs two 32x40 arrays of superconducting transition-edge sensors, which operate at 100 mK. An open bucket dewar of liquid helium maintains the receiver and telescope optics at 1.7 K. We describe the thermal design of the receiver and sub-kelvin cooling with a continuous adiabatic demagnetization refrigerator (CADR). The CADR operates between 70-130 mK and provides ~10 uW cooling power at 100 mK, nearly five times the loading of the two detector assemblies. We describe electronics and software to robustly control the CADR, overall CADR performance in flight-like integrated receiver testing, and practical considerations for implementation in the balloon float environment., Comment: 14 pages, 12 figures

This paper presents a theory to explain how detectable defects are generated during a material’s transition from a liquid state into a solid film. The hypothesis of defect formation is that it occurs as a result of an imbalance of molecular forces and molecular motion during the material phase transition. Experimental validation was done using a model spin-on silicon hardmask. Spin time and bake temperature were studied as process parameters to control defect counts. Wide variations in the resulting defect counts show strong statistical significance. The experimental results fit very well with the hypothesis. This preliminary study on defect mechanisms gives a direction to develop nextgeneration defect-free materials. 10.1149/06001.0293ecst ©The Electrochemical Society ECS Transactions, 60 (1) 293-302 (2014)

This paper presents the results of efforts to achieve a very wide processing window lithography using a spin-on trilayer patterning stack. Materials design and processing are based on physical and chemical properties as well as optical field distribution and focus on molecular forces between resist and substrate. All of these factors closely affect line edge roughness/line width roughness (LER/LWR) and critical dimension (CD) processing window (PW). The technique aims to provide an extremely wide CD PW for producing lines and contact patterns in a single lithographic process. The wide depth of focus (DOF) performance allows the printing of difficult patterns having low image contrast, simplifying optical proximity correction (OPC) and source mask optimization (SMO) to make patterning more robust. Scanning electron microscope (SEM) cross sections of the lithography results are presented, and these results are compared to optical simulations.

Background: Current health care practices aim for cost reduction to achieve maximal benefit. Because of the increasing number of spinal fusions, this area has become a target for both hospitals and payment organizations. Length of stay (LOS) is one potentially modifiable variable to help reduce overall cost. Attempting to predict the LOS in spinal surgery based on patient factors has not revealed a set of variables that are consistently associated with increased stay. Methods: Medical records from all patients who underwent posterior lumbar spinal fusion by a single neurosurgeon at a single facility were retrospectively examined in a blind fashion. Data were obtained including age, gender, body mass index (BMI), American society of Anesthesiologists (ASA) and analyzed to determine a potential relationship with LOS. Results: A total of 1360 patients were identified for analysis. There were significant but small correlations between age, ASA, BMI, and LOS. Conclusions: There is an effect of age, ASA, and BMI on LOS. However, the significance of this effect is small. Future studies aiming to identify additional factors, which could potentially be modifiable, in order to work on decreasing LOS in lumbar spinal fusion patients.

It is well known that patterning materials are sensitive to many factors that determine lithography performance. For example, when the same resist is used with various underlayers optimized to the same optical distribution, the different underlayers can produce totally different outcomes. In addition to possible chemical effects (diffusion, acid/quencher interaction, etc.), molecular forces could help explain the entire phenomenon if a pattern profile is built up incorporating fluid dynamics simulation. Because current simulation tools do not take into account the molecular forces, comparing experimental data to simulation results can help isolate the effects of such forces. In this work, a full physics model of the PROLITH™ simulation tool was used to run simulations and to fit experimental lithography data. Experimental data were obtained from KrF contact holes patterned using two different underlayer materials. From this comparison, we can postulate that controlling molecular forces, such as surface tension, can help improve lithography performance beyond what simulation predicts. This approach allows for a potentially wider critical dimension (CD) process window by deviating from traditional lithography modeling. As patterning processes are developed to produce increasingly smaller feature sizes, molecular forces will have a greater effect on optical imaging and should be given more attention.

Despite competition, newspapers still have a potentialcompetitive advantage as a community resource and leader. Therefore, if newspapers want to succeed, they need to position themselves as “community assets.” This research establishes the current measures of circulation and penetration as weak indicators of community service, and presents a simple and straightforward measure of how well a given newspaper serves its entire community using a summary statistical measure of inequality, the Gini coefficient.

This study develops an analytical framework which helpsexplain how media convergence can impact ownership decisions of largemedia companies. It then uses data on nine large U.S. media companies toexamine what impact the Internet and media convergence have had on their M&A activity. The study finds that how a firm conceptualizes theInternet relative to its existing business has a significant impact on M&Aactivity—and understanding investing in the Internet as being more about change than simply growth is key to success.

The Changing Business of Journalism and Its Implications for Democracy. David A. L. Levy and Rasmus Kleis Nielsen, eds. Oxford, UK: Reuters Institute for the Study of Journalism, 2010. 89 pp. £12 pbk.Much of what is written today, especially in the United States, about the business of journalism focuses on one of two issues: the significant decline in both audiences and revenue for traditional journalism enterprises, especially newspapers, and the role of the Internet in precipitating or exacerbating these declines. This "crisis" is generally seen as a serious threat to the contribution that these organizations make to democratic societies-indeed, this perceived harm to democracy is the driver of much of this literature. Moreover, there is usually an implicit assumption that what is happening in the United States is also happening elsewhere or soon will.Enter now this slim new book published by the Reuters Institute for the Study of Journalism at the University of Oxford, a volume that represents the collective effort of a dozen internationally known scholars, mainly European, and part of the Reuters Institute's continuing series. The book's stated purpose is to challenge the doom and gloom that dominates much of the current narrative by offering a systematic overview of what is happening in a diverse range of countries. And it very effectively accomplishes this goal.The book's global approach adds three important elements to the current discussion about the future of the journalism business. First, it emphasizes the need to isolate the role of cyclical factors in the current crisis-in particular, the impact of the current recession-from more fundamental ones. Second, it provides an approach to distinguishing between challenges that are the result of the Internet per se and those that stem from structural characteristics of the journalism industry in a given country. Finally, by taking a neutral approach to the Internet's impact on traditional news businesses and on the health of democracy, it provides a framework for considering a wide range of possible positive outcomes.The first three chapters of the book provide the conceptual and empirical foundation for the seven country studies that are the heart of this volume. This introductory section begins with the book's editors-both research fellows at the Reuters Institute- presenting a wide variety of statistics (on advertising and other news media revenues, profits, public funding, newspaper circulation, and Internet usage) to make the point that the current state of news media is very different across the seven countries.Then Robert Picard, the Reuters Institute research director, offers an excellent summary of the key factors underlying the current crisis in the news media. In doing so, he links two important points: (1) that "serious news" itself has never been profitable as a business and has always required some sort of subsidization and (2) that the decline in newspaper circulation is not the result of a decline in citizen demand for serious news (which in his view has always been limited) nor greater competition in producing it but rather an increase in competition for other types of news (sports, arts and entertainment, celebrity, travel, etc. …

We have measured the thermal conductance of a mechanical heat switch actuated by a piezoelectric positioner, the PZHS (PieZo electric Heat Switch), at cryogenic temperatures. The thermal conductance of the PZHS was measured between 4 K and 10 K, and on/off conductance ratios of about 100–200 at lowest and highest measures temperature were achieved when the positioner applied its maximum force of 8 N, respectively. We discuss the advantages of using this system in cryogenic applications, and estimate the ultimate performance of an ideal PZHS.