bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Non-Uniformity of Electric Field on Breakdown Strength of Cryogenic Gaseous Insulation Media for Superconducting Power Applications
Authors: Telikapalli S. , Kvitkovicova M. , Cheetham P. , Park C. , Kim C.H. , Graber L. , Pamidi S. 
Published: June 2020

Abstract
A new experimental set up for measuring the breakdown strength of gas media in weakly non-uniform electric field at cryogenic temperatures and high pressures is described. Measure of breakdown strength of helium gas at 77 K and 293 K in a non-uniform electric field with a field efficiency factor 62.5% are presented. The results suggest that the breakdown strength in weakly non-uniform electric field relate to that of uniform electric field by the field efficiency factor, η. This relationship holds good for both 293 K and 77 K data. This observation expands our previously reported systematics of dielectric strength in uniform electric field to the weakly non-uniform electric field conditions, which is important for designing HTS power applications. The established relationship eliminates the need for costly experiments for measuring the dielectric strength at a specific operating temperature and pressure and in the required non-uniformity of the electric field.
Thermal and Electrical Properties of Isocyanate Derived Organic Aerogels for Cryogenic Insulation Applications
Authors: Churu G , Demko J A , Mole A , Duckworth R C , Lu H , Malakooti S , Leventis N 
Published: June 2020

Abstract
The use and storage of cryogens such as liquefied nitrogen, helium, hydrogen among others requires reliable and efficient thermal insulation systems. Passive insulation from high performance materials that are well-known for their inherent low thermal conductivity would reduce the overall costs involved in design, manufacture and maintenance of such systems. One such class of materials are referred to as aerogels. These materials are known for their low density, high mesoporosity, high surface areas, low thermal conductivity and high acoustic impedance. Aerogels were invented by S.S. Kistler in 1931 and the most common type are those made of silica. However, the inherent fragility of silica aerogels makes them hard to mass produce, and therefore applications have been limited. A major breakthrough was introduced by our team almost 20 years ago with the invention of polymer crosslinked silica aerogels. Those materials shifted attention to all-polymer aerogels that have overcome all fragility issues associated with their inorganic counterparts. This study focuses on such polymeric aerogels that can be mass produced as large monoliths while maintaining the low thermal conductivity of traditional silica aerogels over a wide temperature range. Manufacturing flexibility of polymeric aerogels allows fabrication of blocks and sheets that can be applied in various configurations to insulate cryogenic and superconducting devices. The thermal conductivity with 80 K and room temperature boundary are reported as well as other properties (electrical), that need to be considered when designing devices for cryogenic applications.
Macroflash boiloff calorimetry instrument for the measurement of heat transmission through materials
Authors: Fesmire J E , Bateman C D , Thomas J L 
Published: June 2020

Abstract
The Macroflash is a flat plate boiloff calorimeter that provides effective thermal conductivity (ke) data for a wide range of materials from thermal insulation to structural composites to ceramics. The apparatus and method provide a practical, standardized way to measure heat transmission through materials under steady-state conditions at below-ambient temperatures and under different compressive loads. Another unique feature of this device is that it can provide test data at both large and small temperature differences. Using liquid nitrogen as a method to directly measure the heat flow rate, the device is applicable to testing under an ambient pressure environment at a wide range of temperatures, from 77 K to 403 K. Test specimens may be isotropic or non-isotropic; homogeneous or non-homogeneous. The Macroflash is currently calibrated in the range from approximately 10 mW/m-K to 1,000 mW/m-K using well-characterized materials. Reference data for hundreds of test specimens including foams, powders, aerogels, plastics, composites, carbon composites, wood, glass, ceramic, metal, and multi-layered composites have been compiled from Macroflash testing. The Macroflash apparatus is described and its operation, instrumentation, and control system discussed. The calibration approach is detailed as well as analysis of key data sets of standard materials.
Understanding Surface Flashover in Helium Gas Cooled High Temperature Superconducting Devices
Authors: Al-Taie A , Cheetham P , Kim C H , Park C , Graber L , Pamidi S V 
Published: June 2020

Abstract
Surface flashover voltage on solid insulators in gas cooled superconducting power devices is studied. The relationship between the surface flashover voltage and the dielectric strength of the gas media is established. Analysis of the data on surface flashover voltage measurements on cylindrical samples made of high-pressure fiberglass laminate (G10) in three different gas media with varying dielectric strength and pressure showed a positive correlation between the surface flashover voltage and the dielectric strength of the gas both at room temperature and 77 K. The positive relationship, however, is not linear. The results suggest that using gas media with higher dielectric strength, employing higher pressure, and lowering temperature in HTS power devices leads to higher surface flashover voltages and higher operating voltages because surface flashover is usually the limiting voltage in devices that use solid support structures and possess voltage gradients.
High throughput and variable temperature superconductor integrated circuit test and evaluation using ICE-T
Authors: Sahu A , Chonigman B , Talalaevskii A , Dotsenko V , Ruotolo S , Tang J , Gupta D 
Published: June 2020

Abstract
Superconductor digital integrated circuits (ICs) require rapid evaluation of multiple copies to obtain statistical operational data. These data are used for assessing model-to-hardware correlation and facilitate iterative IC design development. The Integrated Cryogenic Electronics Testbed (ICE-T) is a cryogen-free test platform, which can test multiple chips simultaneously with similar convenience to a liquid-helium immersion probe and with cooldown times of between 3.3 to 4.5 hours. We have developed a three-chip insert to increase the volume of chip testing and demonstrated simultaneous cooling of six chips with two such inserts. We report the test statistics collected from 27 chips across a single wafer. We have also used the ICE-T’s convenient temperature control system to evaluate chips in the 3.5 - 6 K range. Such evaluation determines the robustness of circuit design and its tolerance to critical current fluctuations due to fabrication variation.
A study on the extent of Ag protrusions in different TiO2-coated Bi-2212 wires
Authors: Hossain S I , Jiang J , Trociewitz U P , Lu J , Bosque E , Kim Y , Larbalestier D C , Hellstrom E 
Published: June 2020

Abstract
We report on the extent of Ag protrusions into the TiO2 insulation layer on 9 different Bi-2212 wires after overpressure heat treatment. These wires were made with different powders and had different diameters and geometries, including aspected and twisted wires. To replicate coil heat treatments, we also studied whether increased time spent in the melt state affects the protrusions. We found that Ag protrusions are not universal and increasing the time in the melt state does not affect the protrusions.
The effect of APC/YBCO interface on the angular range of effective pinning by one-dimensional artificial pinning centers in YBa2Cu3O7-xnanocomposite films
Authors: Ogunjimi V , Gautam B , Sebastian M.A. , Haugan T , Wu J 
Published: June 2020

AbstractThe APC/YBCO interface has been reported to directly affect the pinning efficiency of 1D APCs atB//c-axis. This raises a question on how the APC/YBCO interface affects angular range of the pinning effectiveness for a given 1D APC. In this work, two types of 1D APCs of different APC/YBCO interfaces and hence pinning efficiencies were selected to understand the correlation of the pinning efficiency atB//c-axis and the angular range of the effectiveness. Specifically, BaZrO3(BZO) and BaHfO3(BHO) 1D APCs were selected for a comparative study in the APC/YBCO nanocomposite films. The BZO and BHO 1D APCs have comparable diameters in the range of 5-6 nm. In the doping range of 2-6 vol.%, both BZO and BHO formc-axis aligned 1D APCs in YBCO films. However, differences are present at their interfaces with YBCO. While the BZO/YBCO interface is semi-coherent, a coherent BHO/YBCO interface has been found to be critical to the higher pinning efficiency of the BHO 1D APCs. Therefore, they provide ideal systems for investigation of the angular range of pinning effectiveness by 1D APCs. By evaluating the nanocomposites’ maximum pinning force density (Fp, max) and its locationBmax, normalized to that of the reference YBCO film as functions of magnetic field (B) orientation at temperatures of 65–77 K, a quantitative correlation between the pinning efficiency of the BZO 1D-APCs and their effective angular range was obtained. Our results indicate that all 1D APCs can provide enhancedBmaxover certain angular ranges away from thec-axis. However, 1D APCs with higher pinning efficiency, such as BHO 1D APCs can have enhancedFp, maxover the entire angular range ofB-orientations at temperatures of 65-77 K with respect to that for the reference YBCO sample.
Homopolar superconducting AC machines, with HTS dynamo driven field coils, for aerospace applications
Authors: Kalsi S , Badcock R A , Hamilton K , Storey J G 
Published: June 2020

Abstract
There is worldwide interest in high-speed motors and generators with characteristics of compactness, light weight and high efficiency for aerospace applications. Several options are under consideration. However, machines employing high temperature superconductors (HTS) look promising for enabling machines with the desired characteristics. Machines employing excitation field windings on the rotor are constrained by the stress limit of rotor teeth and mechanisms for holding the winding at very high speed. Homopolar AC synchronous machines characteristically employ both the DC field excitation winding and AC armature windings in the stator. The rotor is merely a magnetic iron forging with salient pole lumps, which could be rotated at very high speeds up to the stress limit of the rotor materials. Rotational speeds of 50,000 RPM and higher are achievable. The high rotational speed enables more compact lightweight machines.
This paper describes a 2 MW 25,000 RPM concept designs for machines employing HTS field excitation windings. The AC armature winding is made of actively cooled copper Litz conductor. The field winding consists of a small turn-count HTS coil that could be ramped up or down with a contactless HTS dynamo. This eliminates current leads spanning room-temperature and cryogenic regions and are major source for thermal conduction into the cryogenic region and thereby increase thermal load to be removed with refrigerators. For early adaption of this technology for the aerospace applications, this 2 MW machine weighing 380 kg with an efficiency > 99% represents an attractive option.
2-layer Cable-in-Conduit for Hybrid-Coil Magnets
Authors: Breitschopf J , Chavez D , Elliott T. , Kellams J , McIntyre P , Sattarov A 
Published: June 2020

Abstract
Recent results are reported in the development of 2-layer cable-in-conduit (SuperCIC) that is designed for use in hybrid-coil magnets. SuperCIC preserves the full performance of the individual wires, and can be formed into flared-end windings for dipoles into layer-wound toroids and solenoids for hybrid windings for tokamaks. The structure of the SuperCIC windings is designed to accommodate winding and heat-treating sub-windings of Bi-2212, Nb3Sn, and NbTi separately and then assembling them and preloading in the magnet.
Development of HTS Current Leads for the ITER Project
Authors: Bauer P , Ballarino A , Devred A , Ding K , Dong Y , Niu E , Du Q , Gung C Y , Han Q , Heller R , Huang X , Ichihara T , Lee S , Li J , Liu C , Liu Cl , Lu K , Mitchell N , Song Y , Spina T , Ran Q , Taylor T , Yamada S , Yang Y , Zhou T 
Published: June 2020

Abstract
The HTS current leads for the ITER project will be the largest ever operated, with unprecedented currents, up to 68 kA and voltages, up to 14 kV. According to the ITER agreement they will be provided in-kind by China. After an extensive development program at the Hefei Institute of Plasma Physics (ASIPP), the ITER current leads were designed and qualified. The following discusses the main highlights of this development, with particular emphasis on the description of the design of the different types of ITER current leads and their final qualification in dedicated cold tests in nominal conditions.
Evaluation of triangle´s triple restriction on conventional construction and modular construction-Example: New building of the University of the Coast
Authors: de la Puente Molina S E , Espitia Ticora J L , Capera Rodríguez O A , Palomeque Sánchez Z A 
Published: June 2020

Abstract
This document evaluates and compares the modular construction system against the conventional construction system, analyzing it from the triangle of the triple restriction of the PMBOK guide (5th edition), which corresponds to the analysis of the scope, time and cost that can be achieve in the execution, which is focused directly on a real building of higher education, as a case study was used the university corporation of the CUC coast located in the city of Barranquilla. The main purpose of the research is to demonstrate the strengths, advantages and disadvantages of each construction system and once the real results were obtained to be able to make the application in professional practice for the management of the works and the execution of higher education projects, in this way the new construction processes are potentialized as a contribution to the development of architecture and innovation in Colombia, which is a country that is seeking to enter new methodologies and construction systems which must be aligned with the management issues that are being applied in the construction guild.
Evaluation of the coughing power of the Opuntia ficus indica for removal of turbidity in waters of the Guatapuri River (Colombian Caribbean)
Authors: Vidal-Tovar C R , Moscote-Vides E M , Vides-Redondo A J , Severiche-Sierra C A 
Published: June 2020

Abstract
The purpose of this article is to publicize the evaluation of the effectiveness of Opuntia ficus indica as a coagulant during the treatment of raw water from the middle basin of the Guatapurí River, in the Department of Cesar, Colombia. Tuna coagulant is purely organic; it has been shown by phytochemical studies performed on Opuntia ficus indica the presence of some minerals among some others; contains glycides or carbohydrates. The evaluation was carried out using the jug test equipment, which operated by varying the revolutions per minute (20, 30 and 40), keeping the mixture fast at 125 rpm and settling for 30 minutes. The samples were physically characterized (Turbidity, Alkalinity, pH and total suspended solids) taking into account the methods specified for parameter in the Standard Methods. With samples of 345.9 NTU and 2799.1 NTU at optimal doses of 658.75 mg/L and 1976.3 mg/L respectively, removals up to 97% and 99.5% were observed in the same order. It was shown that the variation of the slow mixture only influenced with the sample of 2799.1 NTU, being the most effective treatment at 30 RPM.
Obtaining a sugar syrup from the use of the extract of the guácimo fruit (Guazuma ulmifolia lam)
Authors: Vidal-Tovar C R , Cadavid-Osorio C A , Angulo-Blanquicet G E , Severiche-Sierra C A 
Published: June 2020

AbstractThe main objective of this work was to elaborate a sugary syrup from the use of Guácimo fruit extract (Guazuma Ulmifolia Lam) using the leaching method (solid - liquid), which can be used as a partial or total substitute for sugar. The experimental design that was applied for the extraction process was a factorial design 23; the data obtained were evaluated with the software Statgraphics. Once the extracts were obtained, physico-chemical tests were carried out and reductive sugars and dextrose equivalent were determined in each one. To obtain the syrup, the four extracts having the highest% ED were concentrated at constant temperature and time (50 ° C and 4 hours); The determination of the presence of reducing sugars was done using the techniques of colorimetric analysis (miller’s method) and chromatography (HPLC). The products that were obtained during the process were extreme conversion syrups with a range of dextrose equivalents of 90.13% - 98.27%. The syrup that obtained the highest percentage of equivalent dextrose (J3) was subjected to a sensory hedonic test, which consisted of 3 samples of sweetened coffee at different concentrations of sweet sugar syrup and sugar (sucrose), where M1 contained 80% sugar syrup of guácimo and 20% of table sugar. M2 contained 50% guácimo sugar syrup and 50% table sugar. M3 contained 100% sugar guacimo syrup and 0% table sugar. The results showed that the mixture that obtained the highest organoleptic acceptance was M2, followed by M3, which states that the syrup can substitute partially the common sugar. The above data allow the guácimo fruit to be taken into account as an alternative raw material for the production of sugar syrups and other products aimed at human consumption.
Scientific reasoning skills and patterns of use of Information and Communication Technologies. The case of the students of the Universidad de Santander (Valledupar, Colombia)
Authors: Angulo Blanquicett G E , Angulo Blanquicett G E , Vidal-Tovar C R , Rios-Dominguez I C 
Published: June 2020

Abstract
This research establishes the relationship that has had the development of the skills of scientific reasoning and the patterns of use of tools and resources of information and communication technology (ICT). For that, it is necessary to use Lawson Test and to have into account ICT National Standards for students that USA International Society for Technology in Education (ISTE) suggest. Also, this paper is tackled from a non-experimental design featuring a correlational – transectional range. The population consists of 2035 students from a higher education institution of the Colombian Caribbean coast. Besides, stratified random sampling is used defining, defining strata and a representative sample for academic programs. Personal survey was used to collect information. The existence of relationship between scientific reasoning skills and patterns of use of information and communication technology was confirmed.
Traffic flow prediction model and probability of congestion
Authors: Pilamunga Poveda M , Lavin J M , Aldás Sánchez M , Ríos Insua D 
Published: June 2020

Abstract
Investment in the management of integrated activities for better community development determines the progress of a city. Generate actions directed to change and evolution can promote greater satisfaction among its inhabitants. One of those activities is the one concerning transit, which is one of the most transcendental factors in the quality of life of a modern city. Thus, good road planning is of vital importance for their development. To do this, studies must be conducted that allow us to have a diagnosis of reality and thus make decisions would help to minimize or avoid problems that are occurring or that may appear in the future. However, to make a study of this type whenever it is required is expensive in terms of time and resources. This work proposes a model that allows predictions of traffic flows in different relevant sections of a city and, predict issues such as traffic saturation in them, thus determining possible solutions to road congestion, it can be presented at a given moment. These possible alternative solutions could consequently would reduce costs in time, fuel, pollution among others.
Identification of critical variables in conventional transformers in distribution networks
Authors: Marriaga-Márquez I.A. , Gómez-Sandoval K.Y. , Grimaldo-Guerrero J.W. , Nuñez-Álvarez JR 
Published: June 2020

Abstract
Transformers are essential equipment to the operation of electrical power systems, a failure causes the lack of electricity supply to end-users, affecting the operating indicators of companies in the distribution sector. The investigation presents an identification of the faults in transformers through a fishbone diagram, an evaluation of the variables that cause the identified failure using the cross-impact matrix method and a proposal to improve the performance. The results will enable a plan to be developed for taking action with monitoring plans to avoid faults that could put the electrical asset at risk and achieve a better performance of the distribution network.
Drivers of Biomass Power Generation Technologies: Adoption in Colombia
Authors: Reyes-Calle W , Grimaldo-Guerrero J.W. 
Published: June 2020

Abstract
The share of non-conventional renewable energies in Colombia represents less than 4% of electricity generation; the government aims to increase the net installed electricity generation capacity to over 10% by 2028. A structural analysis was carried out for decision-making: international experiences was used to identify Social, Environmental, Technical and Economic indicators and with the MICMAC method, the key variables were identified to define improvement strategies. This research determined the driver elements that will allow Colombia to effectively include biomass as an electrical energy source.
Degradation of Cyanide from Gold Mining Wastewater Using Photocatalysis
Authors: Mestre-Martinez R M , Marrugo-Pautt I , Correa-Turizo R R , Severiche Sierra C A , Baldiris-Navarro I 
Published: June 2020

Abstract
In recent years, water quality issues related with hazardous wastewater and toxic substances have attracted worldwide attention. Cyanide is a major toxin in wastewater resulting from a diversity of industries, including gold mining. Cyanide has adverse health effects on people as well as other living organisms. The toxic effects of cyanide are so important to cause nerve damage and thyroid glands malfunctioning. In this paper, the degradation of cyanide in waters resulting from gold mining activity was carried out in a batch system with two catalysts TiO2 Degussa P-25 and TiO2 doped with copper heteropolyimolybdate, that was synthesized in laboratory and characterized by FTIR and XRD. Assays showed a degradation of 98.55% with a concentration of 0.3 g/L of TiO2 and 97.17% with TiO2 doped with 1% of Cu heteropolyimolybdate (1 g/L) in 50 min of reaction. A real mining sample showed a cyanide degradation of 55.76% with TiO2 in 240 min of reaction. All the assays were made applying photodegradation using a 125-Watt mercury lamp as source. These results are encouraging to use this technology for the removal of cyanide coming from highly contaminated aqueous effluents.