bluuebunny/crossref_metadata_2025 huggingface dataset:
Polarized evanescent waves reveal trochoidal dichroism
Authors: McCarthy Lauren A. , Smith Kyle W. , Lan Xiang , Hosseini Jebeli Seyyed Ali , Bursi Luca , Alabastri Alessandro , Chang Wei-Shun , Nordlander Peter , Link Stephan
Published: June 2020

Significance

The ability of certain materials to discriminate between two opposite light polarizations is the basic principle behind several technologies such as liquid crystal displays and three-dimensional glasses. While there are numerous forms of light polarization, only linear and circular polarizations, which have wave motion in a flat sheet or helix, respectively, are typically used. Here, we utilize trochoidal polarizations with cartwheeling wave motion. We demonstrate that single gold nanorod dimers can discriminate between trochoidal fields rotating in opposite directions, which we term trochoidal dichroism. Trochoidal dichroism forms an additional classification of polarized light–matter interaction and could inspire the development of optical studies uniquely sensitive to molecules with cartwheeling charge motion, potentially relevant for probing key light-harvesting antennas.
The E3 ubiquitin ligase MARCH1 regulates antimalaria immunity through interferon signaling and T cell activation
Authors: Wu Jian , Xia Lu , Yao Xiangyu , Yu Xiao , Tumas Keyla C. , Sun Wenxiang , Cheng Yang , He Xiao , Peng Yu-chih , Singh Brajesh K. , Zhang Cui , Qi Chen-Feng , Bolland Silvia , Best Sonja M. , Gowda Channe , Huang Ruili , Myers Timothy G. , Long Carole A. , Wang Rong-Fu , Su Xin-zhuan
Published: June 2020

Significance

Malaria kills ∼0.4 million people a year. Malaria parasite infection triggers complex immune responses that may control the infection or result in severe disease. The molecular mechanisms underlying host–parasite interaction and immune regulation are not completely understood. We perform a genome-wide genetic screen during earlyPlasmodium yoeliiinfection in mice and identify a large number of host and parasite genes/loci for future studies of the complex host–parasite interactions. We next investigate the functions of one of these host genes that encodes an E3 ubiquitin ligase (MARCH1). We show that MARCH1 regulates type I interferon signaling, T cell activation, and IFN-γ production during malaria infections. MARCH1 is a key molecule in immune responses and a potential target for immunotherapies.
Rocks in the auxin stream: Wound-induced auxin accumulation and
ERF115
expression synergistically drive stem cell regeneration
Authors: Canher Balkan , Heyman Jefri , Savina Maria , Devendran Ajay , Eekhout Thomas , Vercauteren Ilse , Prinsen Els , Matosevich Rotem , Xu Jian , Mironova Victoria , De Veylder Lieven
Published: June 2020

Significance

Plants show remarkable regenerative abilities, allowing them to recover from wounds and organ loss. This regenerative capacity is controlled in part by auxin, the most promiscuous plant hormone controlling organogenesis and tissue patterning. We show that stem cell death diverges the auxin flow, much like rocks in a stream, resulting in an auxin accumulation in the tissues surrounding the wound. We demonstrate that within these tissues, wound-induced expression of the plant-specific transcription factor ERF115 works synergistically with the change in auxin accumulation, thereby specifying stem cell identity in the cells surrounding the damaged stem cells. This gain of stem cell identity drives formative divisions, allowing replacement of the lost stem cells and thus successful regeneration.
The effects of heritage language experience
on lexical and morphosyntactic outcomes
Authors: Lloyd-Smith Anika , Bayram Fatih , Iverson Michael
Published: June 2020

In heritage language (HL)
bilingualism, recent work has focused on
understanding the dynamic effects that different
input types can have on heritage language
development and outcomes (e.g., Bayram et al.,
2017; Kupisch & Rothman, 2018; Polinsky,
2018; Putnam & Sanchez, 2013; Karayayla &
Schmid, 2019). The underlying question is
to what extent one’s individual experiences with
the HL modulate HL development and its outcomes.
Following this line of research, we provide
evidence from two datasets of Turkish as a HL in
Germany that attempts to identify the relative
ability of various aspects of language experience
(parental background, language use at home, time
spent in the HL country, age of exposure to the
societal majority language, and quality of HL use)
to predict lexical and morphosyntactic performance
in Turkish. The results for the first HS group
(adolescents) indicate that ‘parental language
background’ was the strongest predictor of both
lexical diversity and morphosyntactic complexity;
for the second HS group (adults), “Turkish use in
the home” and “Current Turkish use” were the
strongest predictors. We interpret these results
as evidence for the variable role played by
different types of input in shaping HL outcomes,
highlighting the need for more systematic
approaches to measuring (and predicting) the
effects of input across different areas of
language.
Convergence in the encoding of motion
events in heritage Turkish in Germany
Authors: Goschler Juliana , Schroeder Christoph , Woerfel Till
Published: June 2020

The encoding of motion is a
particularly interesting domain of German-Turkish
language contact. German is a “satellite-framed
language” that easily combines manner-of-motion
verbs with path expressions outside of the verb
stem. Turkish, on the other hand, is considered a
“verb-framed language”, where the combination of
semantically heavy manner-of-motion verbs with
path expressions does not occur. In a sentence
acceptability study with monolingual Turkish and
bilingual German-Turkish students, we tested the
acceptability of Turkish sentences which violate
the canonical Turkish structure to different
degrees. Bilingual Turkish-German speakers more
readily accepted combinations of semantically
heavy manner-of-motion verbs and path
expressions than the monolingual Turkish speakers.
The difference did not show in combinations of
semantically light manner-of-motion verbs and
Path devices. We conclude that we cannot speak of
ad-hoc transfer or a general “insecurity” in the
Turkish of Turkish-German bilinguals. Rather, the
results show evidence for the development of new
grammatical patterns in heritage Turkish in
Germany, influenced by the characteristic encoding
patterns of German.
Taro koji of Amorphophallus konjac enabling hydrolysis of konjac polysaccharides to various biotechnological interest
Authors: Adachi Osao , Hours Roque A , Akakabe Yoshihiko , Arima Hideyuki , Taneba Rie , Tanaka Junya , Kataoka Naoya , Matsushita Kazunobu , Yakushi Toshiharu
Published: June 2020

Due to the indigestibility, utilization of konjac taro, Amorphophallus konjac has been limited only to the Japanese traditional konjac food. Koji preparation with konjac taro was examined to utilize konjac taro as a source of utilizable carbohydrates. Aspergillus luchuensis AKU 3302 was selected as a favorable strain for koji preparation, while Aspergillus oryzae used extensively in sake brewing industry was not so effective. Asp. luchuensis grew well over steamed konjac taro by extending hyphae with least conidia formation. Koji preparation was completed after 3-day incubation at 30°C. D-Mannose and D-glucose were the major monosaccharides found in a hydrolyzate giving the total sugar yield of 50 g from 100 g of dried konjac taro. An apparent extent of konjac taro hydrolysis at 55°C for 24 h seemed to be completed. Since konjac taro is hydrolyzed into monosaccharides, utilization of konjac taro carbohydrates may become possible to various products of biotechnological interest.
The intraocular pressure response to lower‐body and upper‐body isometric exercises is affected by the breathing pattern
Authors: Vera Jesús , Redondo Beatriz , Perez‐Castilla Alejandro , Koulieris George‐Alex , Jiménez Raimundo , Garcia‐Ramos Amador
Published: June 2020

We assessed the mediating role of the breathing pattern adopted during isometric exercise on the intraocular pressure (IOP) response in the back squat and biceps curl exercises. Twenty physically active young adults performed sets of 1‐minute isometric effort against a load corresponding to 80% of the maximum load while adopting three different breathing patterns: (i) Constant breathing: 10 cycles consisting of 3 s of inhalation and 3 s of exhalation, (ii) 10‐sec Valsalva: 3 cycles consisting of 10 s holding the breath and 10 s of normal breathing, and (iii) 25‐sec Valsalva: 2 cycles consisting of 25 s of the Valsalva maneuver and 5 s of normal breathing. A rebound tonometer was used to semi‐continuously assesses IOP during the six sets of 1‐minute isometric effort (2 exercises × 3 breathing patterns). We found a progressive IOP rise during isometric effort (P < 0.001, = 0.83), with these increases being greater when the breath was held longer (P < 0.001, = 0.58; 25‐sec Valsalva > 10‐sec Valsalva = constant breathing). There was a trend towards higher IOP values for the back squat in comparison to the biceps curl, although these differences did not reach statistical significance for any breathing pattern (corrected P‐value ≥ 0.146, d ≤ 0.69). These findings reveal that glaucoma patients or those at risk should avoid activities in which the breath is held, especially when combined with physical exercise modalities that also promote an increment in IOP values (e.g. isometric contractions).
Quasi-Two-Dimensional Diffusion in Adherent Cells Revealed by Three-Dimensional Single Quantum Dot Tracking
Authors: Jiang Chao , Li Bo , Dou Shuo-Xing , Wang Peng-Ye , Li Hui
Published: June 2020

Intracellular diffusion is critical for molecule translocation in cytoplasm and mediates many important cellular processes. Meanwhile, the diffusion dynamics is affected by the heterogeneous cytoplasm. Previous studies on intracellular diffusion are mainly based on two-dimensional (2D) measurements under the assumption that the three-dimensional (3D) diffusion is isotropic. However, the real behaviors of 3D diffusion of molecules in cytoplasm are still unclear. Here, we have built a 3D single-particle tracking (SPT) microscopy and studied the 3D diffusion of quantum dots (QDs) in adherent A549 cells. Notably, we found that the intracellular diffusion of QDs is quasi-2D, with the axial motion being severely confined. Further investigations demonstrated that disrupting the cytoskeleton component or endoplasmic reticulum (ER) does not alter the quasi-2D diffusion pattern, although ER reduces the diffusion rates and slightly relieves the constraint in the axial diffusion. The preferred quasi-2D diffusion is quite robust and attributed to the complex cytoarchitectures in the flat adherent cells. With the aid of 3D SPT method, the quasi-2D diffusion in cells was revealed, shedding new light on the physical nature of cytoplasm.
Strain-induced vibrational properties of few layer black phosphorus and MoTe2 via Raman spectroscopy
Authors: Karki Bhupendra , Freelon Byron , Rajapakse Manthila , Musa Rajib , Riyadh S M Shah , Morris Blake , Abu Usman , Yu Ming , Sumanasekera Gamini , Jasinski Jacek B
Published: June 2020

We studied and compared the effect of tensile strain on the Raman spectra of black phosphorus (BP) and molybdenum ditelluride (MoTe2) crystals by using a simple custom strain device. In-situ Raman spectroscopy on BP revealed clear red shifting of all three phonon modes, A1
g, B2g and A2
g, under tensile stress. From our theoretical analyses, we found that such red shifting strongly depends on the direction of the strain exerted on the system even within the elastic deformation limit (i.e. strain ≤ 1 %). In particular, calculated results for the strain along the armchair direction are consistent with our experimental data, confirming that the strain applied to the sample acts effectively along the armchair direction. In a comparative study, we found that the effect of strain on the Raman shifting is larger for BP than that for MoTe2, presumably due to the smaller Young’s modulus of BP. We also see a remarkable resemblance between donor-type intercalation induced vibrational properties and tensile stress-induced vibrational properties in BP. We anticipate that our method of in-situ Raman spectroscopy can be an effective tool that can allow observation of strain effect directly which is critical for future flexible electronic devices.
Effective suppression of nano-textured black silicon surface recombination channels through sputtered aluminum oxide: A comparison study with ALD grown films
Authors: Parashar Piyush Kumar
Published: June 2020

This accepted manuscript was withdrawn on 2 November 2020 on the author's request.

In this work, the effective surface passivation of nano-textured silicon (NT-Si) using sputtered aluminum oxide (AlOx) films has been demonstrated and established a comparison with atomic layer deposition (ALD) grown AlOx films. Silver assisted wet chemical etching (SAWCE) is used to prepare optically black NT-Si. Sub-wavelength size features of NT-Si surface optimized to control the surface defect states which act as trap centres for charge carriers and proportional to the surface area. Sputtered and ALD grown AlOx films used to passivate the NT-Si surfaces are analyzed primarily in context of available trap centres. The AlOx/NT-Si interface is quantiﬁed by the density of interface trap states (Dit) and the total fixed charge (Qf) that correlated with effective surface recombination velocity (Seff) of carriers. The estimated Dit and Qf of sputtered AlOx films are ~4 x 1011 eV-1cm-2 and ~7 x 1012 cm-2, respectively which results in the Seff of ~37 cm/s due to the field-effect passivation. While the Dit and Qf of ALD grown AlOx films are 1.1 x 1011 eV-1cm-2 and ~7.8 x 1012 cm-2 results in the Seff of ~22 cm/s owing to both the chemical and field-effect passivation.
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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.
Process control system evolution for the LHC Cold Compressors at CERN
Authors: Bradu B , Delprat L , Duret E , Ferlin G , Ivens B , Lefebvre V , Pezzetti M
Published: June 2020

The Large Hadron Collider (LHC) operates using superfluid helium provided by eight large refrigeration units (2.4 kW @ 1.8 K each). These units supplied by specialized cryogenic industrial suppliers are composed of serial hydrodynamic cold compressors based on an axial-centrifugal impeller coupled with volumetric warm screw compressors. The process control systems delivered by the suppliers have been installed, commissioned and operated reliably for more than 13 years. However, the implemented process control closed configuration approach limits of the operational diagnostic, and required operational flexibility and adaptability of the cold compressors systems. In the frame of the CERN evolution of process control standards, the LHC cryogenic operational requirements together with the end of electronic components life cycle has motivated an upgrade of the whole process control system.

Through a step-by-step analysis process including the initial operational risk analysis, CERN has conceived and engineered two prototypes with their dedicated functional analysis and process control logic to cover the complete range of system operation. These prototypes have been initially fully tested in an off-line configuration and after that validated in real system operation.

This paper presents the whole process, the successful results obtained and the perspectives for the future deployment during the LHC Long Shut-Down 2 (2019-2020) period.
Cryogenic system design for the electron-ion collider at Brookhaven National Laboratory
Authors: Ravikumar DJ , Than R
Published: June 2020

Any upgrade of the Relativistic Heavy Ion Collider (RHIC) to an electron-ion collider (EIC) will involve large scale upgrades to the existing cryogenic infrastructure. The challenges to such a project at Brookhaven are unique because of the existing central cryogenic plant. The central plant is oversized for current RHIC operations and can handle the EIC’s heat loads comfortably. However, a lot of equipment will require 2 K cooling for which extra local cryogenic systems are needed. Any new systems will have to be designed to work in tandem with the existing RHIC cryogenic system. This places further constraints on the design of the system, with respect to the cryodistribution system. This study discusses the various baseline configurations for each local cryogenic system for the EIC upgrade.
Helium Management of ESS Cryoplants with Common Safety Relief Header and Recovery System
Authors: Su X T , Arnold P , Nilsson P , Goncalves R , Wang X L , Weisend J. G.
Published: June 2020

The European Spallation Source (ESS) is a neutron-scattering facility being built with extensive international collaboration in Lund, Sweden. Three cryogenic plants with a vast cryogenic distribution system meet the cooling requirements of the superconducting RF cavities in the accelerator (ACCP), the cold hydrogen moderators in the target (TMCP), a cryomodule test stand and the sample environments for neutron instruments (TICP). The first of the three plants, the TICP has been successfully installed, commissioned and acceptance tested in 2018 by Air Liquide Advanced Technologies. Meanwhile the other two cryoplants (ACCP and TMCP) are under commissioning and testing by Linde Kryotechnik AG. The cryoplants share common helium buffer tanks, safety relief headers and helium recovery system due to historical, economical and architectural reasons. The helium recovery strategy and system configuration will be described in the paper. Resulting challenges, risks and safety relevant events that happened during, especially parallel, commissioning activities will be presented. The measures implemented to mitigate major risk and lessons learned are addressed as well.
Oxygen storage module with physisorption technology for closed-circuit respirators
Authors: Swanger A M , Fesmire J E , Fernando R
Published: June 2020

The new Cryogenic Flux Capacitor (CFC) technology employs nano-porous aerogel composites to store large quantities of fluid molecules in a physisorbed solid-state condition at moderate pressures and cryogenic temperatures. By its design architecture, a CFC device can be “charged” and “discharged” quickly and on demand according to standby/usage requirements. One of three main application areas is the CFC-Life for breathing air or oxygen supply to meet new demands in life support systems. Through the Liquid Oxygen Storage Module (LOXSM) Project, the National Institute for Occupational Safety and Health, and Cryogenics Test Laboratory have partnered to test the feasibility of applying the CFC technology to Closed-Circuit Escape Respirators (CCER), or respirators operating on the closed-circuit principle in general. The envisioned Cryogenic Oxygen Storage Module (COSM) is an innovative concept to store oxygen in solid-state form, according to physisorption processes at any cryogenic temperature, and deliver it as a gas using the CFC as the core storage element. Gaseous oxygen would be admitted into the breathing loop of the CCER by introducing heat into the storage module. Potentially replacing the gaseous or chemical based oxygen supply used in today’s closed-circuit respirators, the COSM is a high capacity, conformal, small-size solution for future life support equipment of all kinds. In particular, are the CCER devices that must to be carried on the person, ready to be quickly deployed and used for escape in an emergency. Initial test data for physisorption of oxygen in aerogel materials and CFC core modules are presented. The basic operational parameters for charging and discharging are summarized through prototype testing of the cryogenic oxygen storage module.
Commissioning plan for LCLS II 2 K cold box
Authors: Bhattacharya R. , Arenius D. , Kaufmann C. , Laverdure N. , Scanlon C. , Hogan J. , Bevins M.
Published: June 2020

Commissioning of the LCLS II cryogenic plant has been planned with respect to electrical and mechanical systems checkout, equipment cleanup, cool-down, and individual performance evaluation. This plant consists of warm and cold storage, helium compressors, 4.5 K and 2 K cold boxes, and all auxiliaries typical for helium refrigeration processes. The 2 K cold box, consisting of five cold compressors in series to produce the flow and pressures necessary for 2K operation, will be the last equipment installed and, along with an additional 10,000 L helium dewar, will allow the entire plant to be commissioned as a single entity. The pre-commissioning stages, commissioning plan for 2 K cold box without connecting to the LCLS II LINAC, additional test equipment needed to simulate the loads, all process studies and associated results are described herein.
Frequency Loss Induced Quench (FLIQ) Protection System for Insulated Coil REBCO Magnets
Authors: Ijagbemi K , Davis D , Stiers E , Bai H , Pamidi S
Published: June 2020

Frequency Loss Induced Quench (FLIQ) system is a novel technique that relies on generating AC losses to uniformly heat a superconducting coil to induce a safe and rapid quench. FLIQ drives an imbalance in the transport current between two or more sections of the magnet. To drive the imbalance, FLIQ uses an H-bridge design with Insulated Gate Bipolar Transistor (IGBT)s, whose gates are controlled based on the current feedback, allowing the system to operate at resonance. Simulation of estimated energy per volume deposited by FLIQ and sensitivity analysis of its parameters are performed and the results presented. Application of FLIQ for protection of high temperature superconducting (HTS) magnet systems is described.
Electrical faults in high temperature superconducting power cables for MVDC power systems of all-electric ships
Authors: Stamm T , Choi J H , Cheetham P , Park C , Kim C , Graber L , Pamidi S
Published: June 2020

High temperature superconducting (HTS) power cables are expected to be used in the future in electric ships that will have integrated power and energy systems (IPES). There have been a few studies on understanding electrical faults in power systems consisting of HTS cables; however, there are no comprehensive studies on the response of HTS cables for various types of electrical faults. We have recently initiated a research project on understanding various electrical faults in shipboard medium voltage direct current (MVDC) power systems and the duration of the fault, maximum voltage, and maximum current that the HTS cables will encounter during the fault. This paper presents investigations on the potential cable architectures being developed for MVDC power systems, and the type of faults that HTS cables will encounter in such systems. The paper will assess the relative merits of these architectures in terms of their suitability for accommodating the limitations of cryogenically cooled HTS cables and offer design suggestions for resilient power systems. Electrical and cryogenic thermal models of HTS cables that are suitable for assessing the response of HTS cables for electrical faults, as well as HTS cable designs that can endure electrical faults without catastrophic damage will also be discussed.
Design, Procurement, Installation and Commissioning of the Cryogenic Infrastructure for a New Superconducting RF Test Facility with Beam at CERN
Authors: Delprat L , Brodzinski K , Claudet S , Derking H
Published: June 2020

The High-Luminosity LHC project (HL–LHC), aiming at peak luminosity above 5.0 × 1034
cm
−2
s
−1, considers replacing the matching sections on both sides of the ATLAS and CMS experiments. To complement new focusing quadrupoles, this upgrade considers using the so-called superconducting crab cavities, never operated before with protons and therefore requiring qualification with beam. To this aim, a new cryogenic infrastructure for a superconducting RF test facility was initiated and recently installed at CERN SPS accelerator in 2018. From the early studies of heat load and design principles to the successful tests passed during late 2018, this paper describes the main cryogenic requirements for such a test facility, its design challenges, procurement, installation, and commissioning up to stable operation of the crab cavities module in superfluid helium at 2 K.
Fermilab Cryogenic Test Facilities
Authors: Hurd Joseph , Hansen Benjamin , Wang Renzhuo , Makara Jerry
Published: June 2020

Fermi National Accelerator Laboratory (Fermilab) has multiple cryogenic test facilities, undertaking testing of superconducting magnets, Superconducting Radio Frequency (SRF) cavities, SRF cryomodules and other helium cryogenic components. The test areas within Fermilab include: Meson Cryogenic Test facility (Meson), Industrial Building 1 (IB-1), Heavy Assembly Building/Illinois Accelerator Research Center (HAB/IARC), New Muon Lab, (NML) and the Cryomodule Test Facility (CMTF). Meson and HAB/IARC utilize repurposed Tevatron era reciprocating engine based cryogenic refrigerator systems, whereas CMTF and IB-1 utilize gas bearing turbine based coldboxes. Each of these test areas support the various Fermilab projects and collaborations including the Linear Coherent Light Source II (LCLS-II), Proton Improvement Plan II (PIP-II), High Luminosity Large Hadron Collider (HL-LHC), and Mu2e. This paper outlines the diverse and extensive cryogenic test capabilities within Fermilab.