135,658 research outputs found

    EUV Spectra of the Full Solar Disk: Analysis and Results of the Cosmic Hot Interstellar Plasma Spectrometer (CHIPS)

    Get PDF
    We analyze EUV spectra of the full solar disk from the Cosmic Hot Interstellar Plasma Spectrometer (CHIPS) spanning a period of two years. The observations were obtained via a fortuitous off-axis light path in the 140 -- 270 Angstrom passband. The general appearance of the spectra remained relatively stable over the two-year time period, but did show significant variations of up to 25% between two sets of Fe lines that show peak emission at 1 MK and 2 MK. The variations occur at a measured period of 27.2 days and are caused by regions of hotter and cooler plasma rotating into, and out of, the field of view. The CHIANTI spectral code is employed to determine plasma temperatures, densities, and emission measures. A set of five isothermal plasmas fit the full disk spectra well. A 1 -- 2 MK plasma of Fe contributes 85% of the total emission in the CHIPS passband. The standard Differential Emission Measures (DEMs) supplied with the CHIANTI package do not fit the CHIPS spectra well as they over-predict emission at temperatures below log(T) = 6.0 and above log(T) = 6.3. The results are important for cross-calibrating TIMED, SORCE, SOHO/EIT, and CDS/GIS, as well as the recently launched Solar Dynamics Observatory.Comment: 27 Pages, 13 Figure

    Competitive Foods

    Get PDF
    Describes the types of food items available to middle and high school students in forty California public secondary schools, as well as how well they match the nutrient standards defined in California's SB 12 legislation

    High yield fabrication process for 3D-stacked ultra-thin chip packages using photo-definable polyimide and symmetry in packages

    Get PDF
    Getting output of multiple chips within the volume of a single chip is the driving force behind development of this novel 3D integration technology, which has a broad range of industrial and medical electronic applications. This goal is achieved in a two-step approach. At first thinned dies are embedded in a polyimide interposer with a fine-pitch metal fan-out resulting Ultra-Thin Chip Packages (UTCP), next these UTCPs are stacked by lamination. Step height at the chip edge of these UTCPs is the major reason of die cracking during the lamination. This paper contains an approach to solve this issue by introduction of an additional layer of interposer which makes it flat at the chip edge and thus the whole packages is named as “Flat-UTCP”. In addition to that, randomness in non-functional package positions per panel reduces the overall yield of the whole process up to certain extent. A detailed analysis on these two issues to improve the process yield is presented in this paper. 3D-stacked memory module composed of 4 EEPROM dies was processed and tested to demonstrate this new concept for enhancing the fabrication yield

    Pilot scale pyrolyser : compliance and mechanistic modeling : a thesis presented in partial fulfillment of the requirement for the degree of Master of Engineering in Chemical and Process Engineering at Massey University, Palmerston North, New Zealand

    Get PDF
    "A pyrolysis reactor was built in a previous project by Bridges et al (2013).The reactor is cylindrical in geometry, with a height of 1000 mm and an internal diameter of 750 mm, it stands vertically. There is a 900 mm tall and 100 mm in diameter perforated core in the center of the reactor. At the base, a combustion chamber provides the hot gases required for heating. The hot gases produced travel up and around the reactor through an annulus region of 11 mm. Heat from the gases is transferred to the reactor wall and then to the wood-chips inside. As drying and pyrolysis reactions occur, gases flow in the same direction as the heat towards the perforated core at the center. Hot pyrolysis gases then flow downwards towards the combustion chamber where they are partially combusted before flowing around the reactor and out the flue stack. This project aimed at mathematically modeling this reactor and also improving the way emissions are released so that it complies with EPA air quality standards. A mathematical model of an ‘open source’ pilot-scale pyrolysis reactor was produced to predict the product yield, carbon foot-print, biochar quality and the time taken to achieve complete pyrolysis. A non-equilibrium thermodynamic approach was used which allowed for the use of COMSOL Multi-Physics to solve the model. The Finite Element Method (FEM) was used to solve the system of equations. Pyrolysis kinetics are complex and no single model has yet been widely accepted, therefore simplifications were necessary in this model so that a reasonable solution time could be achieved while producing acceptable results. The model profile of the centre temperature closely followed that of the experimental results and thus the model was considered valid. In addition, modifications were made to the original design of the pyrolyser in order to improve emissions compliance and improve operations of the pyrolysis. It was important to manage fugitive emissions and completely combust any volatile vapours that would be released into the atmosphere while controlling the operating parameters. In order to achieve this, the following were implemented: 1) The combustion chamber was sealed completely so that no fugitive emissions can escape while limiting the ingress of oxygen. 2) A secondary blower was installed in order to better control the oxygen supply to the burners. 3) The original steel lid, which warped during pyrolysis runs resulting in gaseous leaks, was replaced with a more rigid ceramic lid that doesn’t effectively expand when heated. 4) Two 3.4 kW burners were added to the single 3.4 kW burner flare. This gives a total power of 10.2 kW, which is estimated to be enough to completely burn all gaseous products leaving the system"--Prefac

    Chandra News

    Get PDF
    The Chandra Newsletter contains articles about the CXC and the Chandra mission. The Chandra Newsletter appears once a year and is edited by Paul J. Green, with editorial assistance and layout by Evan Tingle. We welcome contributions from readers. Comments on the newsletter, or corrections and additions to the hardcopy mailing list should be sent to: [email protected]

    Implantable RF-coiled chip packaging

    Get PDF
    In this paper, we present an embedded chip integration technology that utilizes silicon housings and flexible parylene radio frequency (RF) coils. As a demonstration of this technology, a flexible parylene RF coil has been integrated with an RF identification (RFID) chip. The coil has an inductance of 16 ΌH, with two layers of metal completely encapsulated in parylene-C. The functionality of the embedded chip is verified using an RFID reader module. Accelerated-lifetime soak testing has been performed in saline, and the results show that the silicon chip is well protected and the lifetime of our parylene-encapsulated RF coil at 37 °C is more than 20 years

    Second-generation bioethanol from industrial wood waste of South American species

    Get PDF
    There is a global interest in replacing fossil fuels with renewable sources of energy. The present review evaluates the significance of South-American wood industrial wastes for bioethanol production. Four countries have been chosen for this review, i.e., Argentina, Brazil, Chile, and Uruguay, based on their current or potential forestry industry. It should be noted that although Brazil has a global bioethanol market share of 25%, its production is mainly first-generation bioethanol from sugarcane. The situation in the other countries is even worse, in spite of the fact that they have regulatory frameworks in place already allowing the substitution of a percentage of gasoline by ethanol. Pines and eucalyptus are the usually forested plants in these countries, and their industrial wastes, as chips and sawdust, could serve as promising raw materials to produce second-generation bioethanol in the context of a forest biorefinery. The process to convert woody biomass involves three stages: pretreatment, enzymatic saccharification, and fermentation. The operational conditions of the pretreatment method used are generally defined according to the physical and chemical characteristics of the raw materials and subsequently determine the characteristics of the treated substrates. This article also reviews and discusses the available pretreatment technologies for eucalyptus and pines applicable to South-American industrial wood wastes, their enzymatic hydrolysis yields, and the feasibility of implementing such processes in the mentioned countries in the frame of a biorefinery.Fil: Vallejos, MarĂ­a Evangelina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Ciencias Exactas QuĂ­micas y Naturales. Instituto de Materiales de Misiones; ArgentinaFil: Kruyeniski, Julia. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Ciencias Exactas QuĂ­micas y Naturales. Instituto de Materiales de Misiones; ArgentinaFil: Area, Maria Cristina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Ciencias Exactas QuĂ­micas y Naturales. Instituto de Materiales de Misiones; Argentin
    • 

    corecore