bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental demonstration of enhanced self-amplified spontaneous emission by photocathode temporal shaping and self-compression in a magnetic wiggler
Authors: Zhang Zhen , Duris Joseph , MacArthur James P , Zholents Alexander , Huang Zhirong , Marinelli Agostino 
Published: June 2020

Abstract
In this paper we demonstrate experimentally the generation of attosecond soft x-ray free-electron laser (XFEL) pulses based on a novel approach to enhanced self-amplified spontaneous emission. Instead of utilizing an external laser, we shape the electron beam at the cathode by laser pulse stacking. We enhance the high-current spike in the beam profile through a self-compression process which uses short-range coherent synchrotron radiation in a wiggler and a downstream magnetic chicane. The undulator taper is then matched with the energy chirp along the beam for attosecond XFEL generation. Start-to-end simulations are performed to demonstrate the proposed method. The measured spectra suggest that a ∼250 as pulse duration is achieved at ∼940 eV in the experiment.
Green Economy for Sustainable and Adaptive Architectures and Cities: Objectives, Guidelines, Measures, Actions
Authors: Tucci F , Battisti A 
Published: June 2020

Abstract
Several analyses and reports in the world of Sustainable and Adaptive Design are pointing in the direction of what is known as a ‘Green City Approach’: an integrated, multisectoral approach to the planning and implementation of improvements that aim to increase levels of well-being, social inclusion and long-lasting development in cities, based on the now decisive aspects of the high environmental quality, efficiency and circularity of resources and on climate change mitigation and adaptation. In Italy, this new approach has been supported by significant contributions. The PRIN Research (Project of Relevant National Interest) “Adaptive Design and Technological Innovations for the Resilient Regeneration of Urban Districts in System of Climate Change” funded by the Italian Ministry of Scientific Research, has developed these themes for three years (2016-2019). In addition, in coordination with PRIN Research developments, in early 2017 the "La Città Futura" Manifesto, presented by lecturers from a dozen universities in the world, was launched as part of the initiatives of the State’s General of the Green Economy, and over the past year the development of this new approach has been boosted by the international Green City Network promoted by the Sustainable Development Foundation (2017-2019). The basic aim was to launch a debate - with a close confrontation with the international design experimentation scenario – and elaborate guidelines fostering future developments as regards the relationship between the main principals that lie at the heart of the Green Economy and Adaptive Design, architectural and urban growth, regeneration, and development, attempting to bring all the cities closer to the development approach of many cities in the world that have already achieved significant results as regards ‘green’ growth and redevelopment.
Evolution of Cryogenic Engineering
Authors: McIntosh G E , McIntosh R C 
Published: June 2020

Abstract
Individual scientists began to address technology problems that would fall in the category of cryogenics in the half century before 1900. Air was liquefied and, in several steps, distillation columns for air separation evolved. The need for pure oxygen and nitrogen motivated industrial improvements and a technology spinoff. Institutions with a department of cryogenic technology emerged in the Netherlands and United Kingdom along with isolated individual scientists. The need for pure oxygen for high altitude aviators in World War II gave local air separation a boost. Military applications provided a strong incentive for cryogenic development until the mid 1950’s. After the first Cryogenic Engineering Conference in September 1954, the technology would become the basis for space flight, superconductivity, high energy accelerators and other low temperature research applications. The introduction of multilayer insulation (MLI) in 1957 had a significant impact on all sizes and forms of liquid dewars. Liquid cylinders, field and storage artificial insemination dewars, liquid helium transport dewars and a wide range of technical applications ensued. Cryogenic engineering has matured and has proven equal to the challenges presented.
Northrop Grumman next generation Mini Cooler Plus performance
Authors: Amouzegar L , Nguyen T , Petach M , Dair E , Abelson L 
Published: June 2020

Abstract
Northrop Grumman Aerospace Systems (NGAS) has expanded its cryocooler product line with the introduction of the Mini Cooler Plus (MCP) pulse tube cryocooler. The cooler is developed to provide a long-life, low-mass, high cooling capacity cryocooler for hyperspectral and infrared imaging payloads in tactical airborne and space applications.
The MCP is a split configuration pulse tube cooler with a passive coaxial cold head connected through a transfer line to a vibrationally balanced back-to-back linear compressor. Designed for space and non-space applications, the MCP’s compressor is scaled from NGAS’ larger flight proven TRL9 family of compressors and contains non-wearing pistons suspended on flexure bearings. The reliability and ten-year lifetime are among the features of this class of pulse tube cryocooler, and have been verified by in-orbit operation of NGAS space flight cryocoolers.
At 300 K reject, this 2.7-kg thermal mechanical unit can lift 1.5 W at 46 K with 150 W electrical input. This cooler is capable of cooling hyperspectral, LWIR (Long-Wave Infrared) and HOT (High Operating Temperature) IR payloads. This paper describes the MCP, its components and interfaces and presents the test data obtained in its laboratory configuration over a range of input powers and reject temperatures.
Vibration-heating in ADR Kevlar suspension systems
Authors: Tuttle James , Jahromi Amir , Canavan Edgar , DiPirro Michael , Kimball Mark , Shirron Peter , Gunderson Chloe , Nellis Jacob 
Published: June 2020

Abstract
The cryogenics group at NASA’s Goddard Space Flight Center has a long-standing development and test program for laboratory and space-flight adiabatic demagnetization refrigerators (ADRs). These devices are used to cool components to temperatures as low as 0.05 K. At such low temperatures the ADR systems can provide a few micro-Watts of cooling power, so it is important to minimize the conduction of heat to these cold stages from the surroundings. The cold ADR elements are held in place by thin tensioned strings made of Kevlar, chosen for its high strength and stiffness and low thermal conductivity. During laboratory testing, we have observed that occasional significant additional heat loads on the coldest ADR stages correlate with unusually high vibration levels in the cryostat due to a noisy mechanical cryocooler. We theorized that this heat results from plastic deformation of the Kevlar fibers and frictional interactions among them, driven by the cryostat vibrations. We describe tests and calculations performed in attempt to confirm this source of the heating.
Theoretical investigation of a closed liquid CO2 energy storage system
Authors: Ji W , Chen L B , Guo L N , Xu H , An B L , Wang J J 
Published: June 2020

Abstract
In order to overcome the disadvantages of uncertainty, randomness and intermittency brought by wind and solar energy, different energy storage systems were put forwarded. Liquid air energy storage is an important technology in solving the grid connection problem of large-scale renewable energy. However, the production of liquid air needs a cryogenic liquefaction technology below a temperature of -150°C, which has a high facility cost and cold loss. Therefore a closed hybrid wind-solar-liquid CO2 energy storage (WS-LCES) system was proposed. In the WS-LCES system, wind power was used to liquefy CO2 and the CO2 was stored in liquid phase with different pressures (90 bar and 8 bar) and temperatures (35°C and -45°C) at both energy storage and release stages. Also, the solar power was stored to increase the energy storage efficiency. For the high density of liquid CO2, the system has a large storage capacity and no geographic constraints. A thermodynamic and parametric analysis was conducted to investigate the optimum system performance.
A two-condenser pulsating heat pipe for use as a passive thermal disconnect in redundant cryocooler implementations
Authors: Mueller B W , Pfotenhauer J M , Miller F K 
Published: June 2020

Abstract
A proof-of-concept, two-condenser nitrogen pulsating heat pipe (PHP) for use as a passive thermal switch in applications with redundant cryocooler installations is developed and tested. The PHP design comprises two independent PHP condensers, each thermally linked to an independent cryocooler cold head, with the two associated PHP evaporators attached to a common cold plate heat load. The design allows the cold plate heat load to be continuously cooled when one cryocooler is non-operating. This is accomplished by leveraging the thermal isolation provided by dryout in the PHP associated with the non-operating cryocooler to limit the parasitic load on the common cold plate (and therefore on the remaining operating cryocooler) from the ambient environment. Mechanical actuation is not required as the PHP thermal switch is fully passive. Instrumentation is included in the proof-of-concept device to measure the heat loads and effective thermal conductivities of each PHP. The design of the system is presented in detail, along with preliminary measurements of PHP heat loads and PHP effective thermal conductivities in states of both pulsating advection and dryout.
Design of a two-stage gas-coupled high-frequency pulse tube cryocooler working around 4 K
Authors: Liu Xuming , Chen Liubiao , Wang Junjie , Zhou Yuan 
Published: June 2020

Abstract
High-frequency pulse tube cryocooler have unique advantages for aerospace and ground applications. However, it is difficult to obtain lower cooling temperature: to obtain the liquid helium temperature, three-stage or four-stage structure by thermal coupling are currently used. In order to further improve the compactness, a two-stage gas-coupled high-frequency multi-bypass coaxial pulse tube cryocooler has been designed. The simulation results indicate that the designed cryocooler can provide a cooling capacity of 25 mW@4.2 K with 416 W input electrical work. The interaction between structural parameters and operating conditions, as well as some preliminary test results will be presented in this paper.
30 K to 2 K vibration free remote cooling systems
Authors: Trollier T. , Tanchon J. , Lacapere J. , Camus P. 
Published: June 2020

Abstract
Absolut System has built a 30 K and a 10 K remote Helium cooling loops used as a vibration free cooling source, respectively for IR detectors electro-optical characterization test bench and two-stage optical cryostat. The circulation loops are based on a by-passed flowrate from either a two-stage Gifford–McMahon cryocooler or a two-stage Pulse Tube cryocooler. Dedicated compact and high efficiency tubes & shell heat exchangers have been designed and produced for the recuperators. The paper describes the design and the performances of the vibration free cooling system produced. The current work towards a 4 K low vibration cooling source will be introduced as well.
Distillation Based CO2 Removal from Natural Gas for Small and Medium Sized Plant
Authors: Manek V , Ghiaasiaan S M , Patelczyk J 
Published: June 2020

Abstract
The removal of excess CO2 from natural gas to levels as low as 50 ppm is essential for the safe and reliable operation of liquefied natural gas (LNG) transport and delivery systems. Current chemical purification techniques, which are suitable for large processing plants, might not be suitable for small or mid-size plants which are expected to operate in future LNG delivery networks. The feasibility of purification of natural gas (NG) from CO2 down to a concentration of 50 ppm by multi-stage distillation is studied. A three-column distillation system is proposed that can purify NG to lower than 50 ppm concentration of CO2, while avoiding CO2 freezeout. The columns include a 30-stage demethanizer, in which high purity methane is obtained in the distillate by separating the impurities from natural gas including CO2; a 50-stage extractive column where the azeotrope between CO2 and ethane is broken; and a 50-stage solvent recovery column that recovers a mixture of heavy hydrocarbons suitable for recycling as a solvent back into the extractive column. The proposed system avoids CO2 freezeout by utilizing a multi component feed of some heavier hydrocarbons added to natural gas; propane, butane and pentane additives are injected into stage 20 of the demthanizer column alongside the raw feed. Furthermore, arrangements are made to break the CO2-ethane azeotrope, which may occur in the bottoms stream of the demthanizer by administering a solvent stream in the extractive column. The proposed system can operate in a closed loop arrangement where the bottoms stream that leaves the recovery column can be recycled and injected into the extractive column for azeotrope prevention.
Oxygen separation in a vortex tube with applied magnetic field
Authors: Raymond J , Bunge C , Henderson G , Leachman J 
Published: June 2020

Abstract
The large scale and efficiency of air separation units remain key barriers towards modular, distributed liquid oxygen systems. Identifying new physical separation mechanisms, or novel combinations of established methods, could enable the development of smaller, more modular air separation systems. This paper investigates the combination of centrifugal separation with paramagnetism of liquid oxygen in a vortex tube. The magnetic field is applied via externally mounted 1.5-T bar magnets along the length of the periphery of the vortex tube. Calibrated air mixtures with 21.1-21.4% oxygen and the remainder nitrogen are tested. Inlet vortex tube fluid conditions are held between 89 and 90 K and 305-320 kPa and expanded to 162-286 kPa. Gas chromatography analysis on the calibrated air samples shows the magnetic field gradient on the vortex tube produces up to a 42.09% purity as opposed to 27.95% purity in identical trials without a gradient. Purity and yield are shown to be inversely related in the periphery and directly related in the core. The results indicate a potential to increase oxygen purity and yield in a more compact form factor.
Freeze-out purifier for helium refrigeration system applications
Authors: Kroll D , Hasan N , Ganni V , Fila A , Engeda A 
Published: June 2020

Abstract
Purification systems are necessary to support commissioning and operation of helium refrigeration and associated experimental systems. These systems are typically designed for a low level of impurity (i.e., in parts per million), since a 4.5 K or 2 K helium system will solidify, or freeze out every other substance. The trace impurities can block and/or change the flow distribution in heat exchangers and potentially damage turbines or cryogenic compressors operating at high speed. Experimental systems, such as superconducting magnets, require helium purification due to inherent characteristics in their construction. These are also used for the commissioning of sub-systems, like the compressors, and cold boxes. As known from experience, molecular sieves do not remove low-level moisture impurity sufficiently. Typical commercial freeze-out purifiers using molecular sieves have very short operating times between regeneration and are inefficient requiring substantial utilities like liquid nitrogen and high-pressure operation. Based upon proven experience from a freeze-out purifier design for Brookhaven National Lab (BNL) in 1983, a liquid nitrogen assisted freeze-out purifier has been designed. This design includes a multi-pass and multi-stream heat exchanger and an activated carbon bed. The heat exchanger design is expected to minimize the liquid nitrogen usage and extend the capacity and the operating pressure range, thereby the time interval between regeneration. The goal is to provide a simple design procedure to develop and operate an efficient purifier system.
Development of a Chatbot Application for Cryogenic System
Authors: Li H.C. , Cheng C. C. , Tsai H.H. , Hsiao F.Z. , Lin Y.Z. , Liao W.R. , Chuang P.S. , Chiou W.S. , Chang S.H. 
Published: June 2020

Abstract
The vacuum group of NSRRC developed a task-oriented chatbot application based on LINE message platform in 2018. LINE message is a cross-platform communication software that can be easily used on mobile phone, tablets, and PC. This interactive user interface can not only reply the real-time status of sub-systems when the user has a query but also proactively report alert. The TPS cryogenic system also introduces this application which like a virtual assistant to help cryogenic engineer management system more efficiency. In this paper we present the configuration and operation of this task-oriented chatbot application for cryogenic system.
Testing of Heat Flux Sensors at Cryogenic Temperatures
Authors: Johnson W L , Balasubramaniam R , Westra K 
Published: June 2020

Abstract
Normally, in order to characterize multilayer insulation installed onto a test tank, the boil-off of the tank is measured and then heat loads from structural and fluid penetrations are calculated from temperature measurements throughout the system. For the Structural Heat Intercept, Insulation, and Vibration Evaluation Rig testing, it was determined that this approach would have significant uncertainties (over 50%) and that another method was needed to characterize the heat load through the blanket. Heat flux sensors are widely used to measure heat loads and characterize insulation systems at room temperature, however, the heat fluxes measured are usually two orders of magnitude higher than high performance MLI. Three different heat flux sensors were initially checked out on a liquid hydrogen calorimeter. One was chosen for actual implementation and 20 sensors were ordered. Of those sensors, calibration was attempted on 7 of the sensors. The results from testing and calibration are discussed.
High level gamma radiation effects on platinum and silicon diode cryogenic temperature sensors
Authors: Courts S S 
Published: June 2020

Abstract
High energy physics research facilities require a vast cryogenic infrastructure to cool superconducting magnets, superconducting RF cavities, and other components to their necessary operational temperatures. The temperature sensors used to monitor this infrastructure are invariably exposed to leakage radiation in varying doses depending upon their location. Compared to many other cryogenic temperature sensors, platinum resistance thermometers (PRTs) and silicon diode thermometers (SiDTs) have the advantages of adhering to standard curves and requiring a single fixed current for operation. This work examines the gamma radiation-induced calibration offsets on two PRT models, the ceramic encapsulated PT-103 and the glass encapsulated PT-111, and a SiDT model DT-670-SD, all manufactured by Lake Shore Cryotronics. Subgroups of each model were subjected to a gamma radiation dose ranging from 10 kGy to 5 MGy with temperature calibrations performed pre- and post-irradiation over their respective operating ranges. The data were analyzed in terms of the temperature-equivalent change in the measured parameter. The PRTs behaved very well in radiation with the PT-103 and PT-111 subgroup average offsets for all tested irradiation levels being less than ±25 mK and ±35 mK respectively over the 20 K to 325 K temperature range. The SiDT model DT-670-SD behavior was more complicated with a clear change in response at 30 K. Below 30 K, the offsets consistently increased from slightly positive to roughly -5 K as the radiation dose increased. Above 30 K, the induced offset had nearly saturated at 10 kGy ranging from about 0 K at 30 K to +23 K at 300 K, and exhibiting that same behavior and offset for all higher radiation doses. Equivalent temperature offset data over the sensors’ operating temperature ranges are presented by sensor model and total gamma dose.
Thermal Acoustic Oscillations: Short Review and Countermeasures
Authors: Putselyk S. 
Published: June 2020

Abstract
Thermally driven oscillations in capillaries of helium cryogenic systems could be observed when a local heat source occurs or a continuous cold to warm temperature transition along capillary exists. These oscillations could lead to a significant heat flux as well as for pressure disturbances. Therefore, it is practically important to design cryogenic systems robust against possible disturbances due to Thermal Acoustic Oscillations (TAO). In the present paper, a short review on available theoretical and experimental results related to the TAO is given. Some tips for a design as well as in-situ countermeasures are discussed.
Cryogenic System for Shanghai Synchrotron Radiation Facility
Authors: Barbier Anne , Xu Jieping , Cui Jian , Machefel Annelise , Mantileri Christophe , Maccagnan Michel , Rogez Edouard , Roig Mathieu 
Published: June 2020

Abstract
The Shanghai Synchrotron Radiation Facility (SSRF) is an intermediate energy light source built at Zhang-Jiang Hi-Tech Park in Shanghai, China. The RF power and voltage required for storing the electron beam are provided by means of three SC (superconducting) cryomodules, each containing one 500 MHz superconducting cavity. A cryogenic plant with cooling capacity of 650 W at 4,5 K (herein called SSRF-I cryoplant) supplied by Air Liquide advanced Technologies has been in operation since August of 2008 to provide cooling for the three superconducting cavities.
In order to further improve the performance of SSRF, the following SC devices are to be applied for the SSRF upgrade (SSRF-II):
1) 2 harmonic SRF (superconducting radio frequency) cavities with 1,5 GHz will run alternatively at 2 K (31 mbar).
2) One superconducting wiggler is to be used for one of the new-built beam lines, ultra-hard multi-functional beam line. The SC wiggler will be cooled by cryocoolers at 4,2 K region.
To support the operation of the new cavities, AL-aT (Air Liquide advanced Technologies) has designed, manufactured and started a new cryogenic system including a 2K system with equivalent cooling capacity of at least 650 W at 4,5 K and 60 W at 2K. The system is mainly constituted of a refrigerator HELIAL MF, an auxiliary 2 K cold box and of a 2 K warm pumping station.
This cryogenic unit has been started successfully at the end of 2018 and has proven performances both at 4,5K and at 2K.