How Lignin, Hemicellulose, and Cellulose Affect the Properties of Oxygen Versus Kraft Pulps

A batch of chips was subjected to an oxygen pulping and a kraft pulping system. The resulting pulp was tested in its unbleached condition. It was then bleached, tested again. Handsheets were tested using the Pulmac zero span tensile tester and other standard physical tests. The pulps were tested using the Pulmac permeability tester. This procedure gave the opportunity to look at how the differences between the individual fibers and their components affect the differences in the strength between oxygen and kraft pulp handsheets. The oxygen pulp was severely degraded than was the kraft pulp. This led to shorter, weaker individual fibers, but fibers with better bondability. The increased bondability gave oxygen pulp handsheets with superior strength in every test except tear. The increased bondability was caused by the higher hemicellulose content in the oxygen pulp. Bleaching increased the strength of both pulps, but oxygen pulp strength was increased to a higher degree. The oxygen pulp also had a larger specific surface area than did the kraft pulp. This increased the number of sites available for bonding which helped to increase the sheet strength. For these handsheets, the bondability played a more important role in the final strength than did the strength of the individual fibers

Comparison of ARAC calculations with surface and airborne measurements for the ACE field trials

These Atmospheric Collection Equipment (ACE) trials were sponsored by the Air Force Technical Applications Center (AFTAC) for the purpose of investigating specific tracer monitoring methods and equipment. Three different tracers (sulfur hexafluoride and two particulate tracers) were released simultaneously for each experiment. This document provides a brief summary of the sulfur hexafluoride modeling results for three of the remaining four ACE trials (the tracer plume from the fifth trial was not located by the monitoring teams and provided no tracer measurements for model comparison). This summary is followed by a discussion of model results for the two particulate tracers which were co-released with sulfur hexafluoride

Low-cost high-performance W-band LNA MMICs for millimeter-wave imaging

The main limitation to the sensitivity of a radiometer or imager is its equivalent noise temperatures, T_e. Placing a low noise amplifier (LNA) at a radiometer's front end can dramatically reduce T_e. LNA performance has steadily improved over recent years, and here we report on a W-band LNA with the lowest T_e measured at room temperature. Furthermore, we present statistical RF data showing high yield and consistency for future high volume production that is needed for commercial radiometric imaging array applications such as security screening, aircraft landing, and other systems

Low-cost high-performance W-band LNA MMICs for millimeter-wave imaging

The main limitation to the sensitivity of a radiometer or imager is its equivalent noise temperatures, T_e. Placing a low noise amplifier (LNA) at a radiometer's front end can dramatically reduce T_e. LNA performance has steadily improved over recent years, and here we report on a W-band LNA with the lowest T_e measured at room temperature. Furthermore, we present statistical RF data showing high yield and consistency for future high volume production that is needed for commercial radiometric imaging array applications such as security screening, aircraft landing, and other systems

High performance MMICs with submillimeter wave InP-based HEMTs

This paper presents some recently developed MMICs based on a 0.1-/spl mu/m gate-length InAlAs/InGaAs/InP HEMT process with an f/sub max/ above 600 GHz. InP-based HEMTs provide more power gain and lower noise at higher frequencies than any other transistor, including GaAs-based pHEMTs. A number of state-of-the-art InP HEMT MMICs will be presented. This includes a 150-205 GHz amplifier with 15 dB of gain, a broadband 60-140 GHz amplifier with 25 mW output power at 140 GHz, a high gain Ka-band LNA and static frequency-divider circuits operating at clock rates above 45 GHz. The high frequency performance of a next-generation 0.08-/spl mu/m-gate InAlAsSb/InAlAs/InGaAs/InP HEMT technology will also be presented

Practical Approach to Surge and Surge Control Systems

TutorialPg. 147-174This paper addresses the area of compressor stability, surge and surge control and relates to the practical aspects involved. An emphasis is placed on the physical understanding of surge phenomena and on the practical limitations of surge control systems. Topics discussed are physical interpretation of instability, causative factors, types of stall, machine and process design factors, surge effects and characteristics, control system types and practical application aspects. Some case studies also are presented. The discussion primarily relates to centrifugal compressors, but several aspects pertain to axial flow compressors as well. The paper is split into three sections: Section A consists of an introduction to surge and a discussion of centrifugal compressor design and process factors that affect operating stability. Section B discusses the various types of control schemes and surge protection devices. Several examples and common pitfalls are addressed. Section C addresses the important design tool, surge system simulation. Several references are provided to enable the reader to pursue this topic in greater detail

Advances in National Capabilities for Consequence Assessment Modeling of Airborne Hazards

This paper describes ongoing advancement of airborne hazard modeling capabilities in support of multiple agencies through the National Atmospheric Release Advisory Center (NARAC) and the Interagency Atmospheric Modeling and Atmospheric Assessment Center (IMAAC). A suite of software tools developed by Lawrence Livermore National Laboratory (LLNL) and collaborating organizations includes simple stand-alone, local-scale plume modeling tools for end user's computers, Web- and Internet-based software to access advanced 3-D flow and atmospheric dispersion modeling tools and expert analysis from the national center at LLNL, and state-of-the-science high-resolution urban models and event reconstruction capabilities

Analysis of a seeder-feeder and freezing drizzle event

Surface icing can cause dramatic consequences on human activities. What is more, numerical weather prediction models are not very accurate in determining freezing drizzle, which creates uncertainty when forecasting this type of weather phenomenon. Therefore, it is essential to improve the forecast accuracy of these models for such phenomena to mitigate risks caused by unforeseen freezing drizzle events. On 5 February 2012, an episode of freezing drizzle took place in the Guadarrama Mountains, at the center of the Iberian Peninsula. This episode was preceded by weak snowfall. After the freezing drizzle, moderate snowfall was recorded in the study area. This event was simulated using the Weather Research and Forecasting model. Through this analysis, we identified the meteorological factors at both synoptic scale and mesoscale that caused this episode. Wind perpendicular to an orographic barrier-generated updrafts and retention of moisture upwind, which caused orographic clouds to appear on the north side of the Guadarrama Mountains. Atmospheric stability prevented cloud formation at midlevels at the time of the freezing drizzle, which maintained cloud top temperatures warmer than −15ºC during the episode. The entrance of moisture and instability at midlevels caused cloud top temperatures substantially colder than −15º C, which coincided with snow in the mountain range. Cloud top temperature and thickness control the efficiency of the glaciation process, thereby determining the type of precipitation at the surface. Freezing drizzle risk and in-cloud icing algorithms were developed with the aim of predicting similar events in the study area, which could mitigate impacts on human activities.This paper was supported by the following grants: TEcoAgua, METEORISK PROJECT (RTC-2014-1872-5), Granimetro (CGL2010-15930) and CGL2011-25327 of MINECO, and LE220A11-2 and LE003B009 awarded by the Junta de Castilla y León

Development of in vitro selection strategies for generating new catalytic nucleic acids and peptides

Design of a nucleic acid library is an essential foundation for an in vitro selection. Increasing the starting diversity of a pool will increase the sampling of sequence space but other strategies must be considered to access rare secondary structures including varying random region length, modularity of the secondary structure and introducing complexity. Efforts to understand these characteristics are reviewed. In vitro evolution of peptides and proteins has been enabled by display technologies such as phage and mRNA display, but each has limitations. To bypass these, a new system that utilizes peptide-DNA conjugations was designed by employing in vitro compartmentalization, which colocalized genotype and phenotype allowing selections. This system could permit a 1014 starting diversity. To optimize DNA and RNA stability in the coupled transcription/translation reaction and the compartmentalized reaction, DNA constructs were designed to code for reporter peptides and altered to increase mRNA stability and translation yields. Pool construction was then optimized and the flanking fixed sequences as well as four bioorthogonal moieties were installed. A mock selection was optimized using an electrophoretic shift mobility assay (EMSA) leading to the same result in the positive and negative controls, which suspended the project. In vitro selection of a ssDNA pool was performed in the presence of fluorescein mono-β-D-galactopyranoside (FMG) and fluorescein di(β-D-galactopyranoside (FDG), substrates for a β-galactosidase. Twenty-one rounds of selection were performed with increasing stringency including a decrease of substrate to 2 µM, a decrease of incubation to 10s and addition of 7 M urea and incubation at 95 °C after the selection reaction. Fluorescence increases were observed when FDG and FMG were incubated with ssDNA from rounds 19 and 21 as well as with individual DNA clones from round 21. Incubation of individual clones with boronate affinity gel did not result in detectable binding, indicating that galactose had not been transferred from the substrate to the DNA clone. Reselection of the DNA pool was performed by competitively eluting bound ssDNA sequences with 0.1 M ribose but it did not result in enrichment of the DNA pool for active sequences over the six additional rounds of selection