Liquid Bath Research Articles

Improving the induction motor power density by its operation at liquid nitrogen bath

This work presents a study of an induction motor at two different operating temperature conditions: room temperature and 77 K. The goal is to analyze its performance and obtain its most relevant features. Experimental tests were carried out in the laboratory under room temperature and liquid nitrogen (LN2) bath. The authors designed a prototype bench with a controlled load to measure magnitudes like torque, speed, current, power, power factor, efficiency, and others. The results show a considerable increase in the torque and efficiency, but in contrast, the starting torque is drastically reduced at cryogenic temperature. Besides, at 77 K, the slip is much lower than at room temperature. The experiments show a substantial rise in the motor’s power density, indicating that cooled induction motors can be applied in applications where volume and weight are restricted.

Evaporation of Leidenfrost droplet on thin soluble liquid bath with thermal non-equilibrium effect

Leidenfrost droplet evaporation on a liquid bath exhibits unique features such as ultra-low resistance to sample transition and low-temperature operation; however, the physical mechanisms responsible for these phenomena are incompletely understood. Droplet size and temperature are two key parameters influencing Leidenfrost droplet evaporation. We report herein the thermal non-equilibrium process of an FC-72 droplet over a thin oil layer. We show that the Leidenfrost droplet radius follows the power law R(t) ∼ (1 − t/τ)n, where τ is the characteristic droplet lifetime and n ranges from 0.63 to 0.91. Based on experimental results and theoretical predictions, the remarkable nonmonotonic variation of droplet temperature departs from the saturation-temperature assumption. For lower oil superheating, a cold (subcooled) droplet can sustain evaporation until it disappears. For higher oil superheating, the droplet goes through both subcooled and superheating stages. This phenomenon is well described by sensible heat absorption and release throughout droplet evaporation. These results are helpful for applications such as drug delivery, wherein a cold droplet can float on a liquid bath, thereby extending the lifetime of the biological sample in a high-temperature environment via a localized, low-temperature system.

Melting time of complex nickel-containing alloys in liquid steel

For development of new ferroalloys and their application, it is necessary to know their physical and chemical characteristics. The most important characteristics of the alloy, on which assimilation and distribution of the main elements of ferroalloys in the iron-carbon melt depend, are their time of melting and dissolution. Using a mathematical model for calculating the melting time, developed by the employees of the Ural Federal University and the Institute of Metallurgy of the Ural Branch of the Russian Academy of Sciences, the authors studied the duration of melting of complex nickel-containing ferroalloys in liquid steel. The program allows one to calculate the temperature of a piece of ferroalloy, thickness of the frozen steel crust, size of the alloy piece and duration of the melting periods depending on physicochemical and thermophysical characteristics of the ferroalloys. The melting mechanism of ferroalloys determines the time of their melting in liquid steel. This work contains mathematical modeling of melting of complex nickel ferroalloys containing %: ~10 Ni; 0.5 – 55.0 Cr; ~0.2 C; ~0.2 Si, in iron-carbon melt. It was found that all the alloys under consideration belong to the group of low-melting ferroalloys and process of their melting proceeds in three periods. With an increase in the initial diameter of ferroalloy piece from 3 to 100 mm, the melting time increases by 250 – 300 times. It is shown that an increase in Cr content up to 37 % in complex alloy leads to a decrease in the melting time, and with a further increase in the Cr content to 55 %, an increase in the melting time occurs. A decrease in temperature of liquid steel bath from 1700 to 1520 °С is accompanied by an increase in the duration of melting of complex ferroalloys by 7 – 8 times. In general, the considered complex nickel ferroalloys are characterized by a much faster melting process in liquid steel compared to standard ferrochrome and ferronickel.

Designing and Manufacturing of the Fully Configured Multiplet for the Super-FRS at FAIR

The First-of-Series (FoS) fully configured multiplet for the Superconducting FRagment Separator at FAIR was designed and manufactured. The cold mass column comprises three quadrupole, two embedded octupole, three sextupole and one steering dipole magnet. Its weight and length are 45 tons and 6.5 m, respectively. The magnets are cooled in a common liquid helium bath by up to 1600 liters of liquid helium. The cold test is currently underway at a dedicated cryogenic magnet test facility at CERN in the framework of a GSI/CERN collaboration. This paper presents the magnetic and cryogenic design as well as the manufacturing of the multiplet.

A Real-Time Monitoring System for Investigating Electromagnetic Behaviors of an HTS Coil

This paper presents a system for real-time monitoring spatial and temporal electromagnetic behaviors of a high temperature superconductor (HTS) coil with the no-insulation (NI) winding technique. We implemented a real-time monitoring system that consists of Hall sensors and voltage taps to measure spatial and temporal magnetic fields, and local voltages. An NI HTS test coil was wound, and the real-time monitoring system was combined with the test coil. An experimental study was performed in a liquid nitrogen bath at 77 K, where the test coil was charged with a constant ramp rate of 0.05 As <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><inline-formula><tex-math notation="LaTeX">$-1$</tex-math></inline-formula></sup> up to its operating current of 100 A. To describe measurement results, including local voltages and magnetic fields, we propose a set of simulations for coil voltages and currents, current density including <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">screening current</i> , and field gradient including <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">screening current induced field</i> . Using this set, we successfully simulated spatial and temporal electromagnetic behaviors generated by the test coil to a reasonable extent. The discussion section will provide comparison results between calculations and measurements.

Progress on the Design of the 15 T Magnet of the EDIPO Test Facility

EDIPO 2 (the upgraded EDIPO test facility) will provide a unique testbed for superconducting cables for fusion magnets, accelerators, and other applications. Compared to the previous magnet assembly, the magnetic field is enhanced from 12.35 T to 15 T, the aperture is enlarged from 90×141 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> to 144×144 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and the uniform field length is increased from 680 mm to 1000 mm (assuming a 1% drop of the field along the sample axis). A number of magnet designs have been proposed for EDIPO 2 since the conceptual design activities started in 2017. The design iterations have converged into a flared-end block-coil dipole design with a purely rectangular cross-section (coil windings aligned on the high and the low-field side). The use of a two-stage cable design is considered in order to increase the operating current, reduce the coil inductance and consequently limit the discharge voltage. The magnet structural design keeps the pre-compression applied to the coil winding pack to a minimum and allows a gap to open between the coils and the test well during operation. Progress on the magnet design activities is reported, including the results of magnetic and mechanical analyses, as well as quench protection studies. The procurement of the helium vessel required to contain the liquid helium bath for magnet cooling is also discussed.

12 T Insulated REBCO Magnet Used as 1 MJ SMES: Protection Strategies and Preliminary Assembly Tests

In the framework of the BOSSE project, a 12 T insulated REBCO solenoid is being manufactured. This magnet will be used as a SMES with the objective to reach 1 MJ and a specific energy of 20 kJ/kg for the winding. To manufacture this solenoid and reach such performances, 21 insulated REBCO Double Pancakes (DPs) will be assembled and cooled in a liquid helium bath at 4.2 K. To validate the solenoid's electromagnetic design, a prototype DP tested in self-field up to its critical current (972 A), thanks to a sensitive protection system, was presented in a previous work. Here we present the background magnetic field test of this prototype DP which allowed to validate the coil's mechanical design. In order to validate the electromagnetic performances of the 21 DPs, each of them is tested in liquid helium up to its rated current. The performances of the 17 DPs already tested and validated will also be presented. Finally, we will present the tests and results of 2 preliminary assemblies of 3 and 5 DPs. These assemblies were tested with two different protection philosophies. The results of these tests show that an individual protection of each DP is to be preferred in order to obtain a better sensitivity on the protection signal.

Electro-Thermal Behavior of Layer-Wound BSCCO Coils With and Without Insulation

In this work, the electro-thermal behavior of two layer-wound High Temperature Superconducting (HTS) coils, realized with and without electrical insulation, is compared. Both coils are wound from the same BSCCO tape, and have a very similar geometry, with the same number of turns and layers. A heat input is applied to both coils, by tuning the current supplied to resistive heaters realized through stainless steel tapes wound on the mandrel at the inner surface of both coils. The heaters are in contact with one full inner turn of the winding. The coils are cooled in a liquid nitrogen bath, and the heaters are supplied with a constant current. Then, the windings are charged until the tape critical current is exceeded, and the tests are repeated for different heat loads. The signals acquired through voltage taps, suitably soldered at the same locations in both windings, are compared at the same testing conditions. Finally, the electrical characteristic of the different layers of the coils is related to the temperature of the heater and of the various turns of the coil by means of a 1-D thermal model.

Improvement of polyethylene fiber wettability and mechanical properties through an environmentally sustainable spinning process

Owing to its simple chain backbone and non-polar structure, polyethylene-based materials exhibit weak adhesion properties in both reinforcement and matrix form. Therefore, development of efficient production strategy is needed for polyethylene fibers with improved wettability and performance. Here, a novel single step modified melt spinning line (MMS) is investigated to obtain linear low-density (LLDPE) and medium density polyethylene (MDPE) fibers with high strength and improved wettability performance. The proposed cost-effective modified spinning system referred as MMS is able to manipulate fiber properties by using non-oily/non-toxic liquid baths, which are located between the melt spinneret and godets, during fiber spinning stage. The aim of this study is to examine the wetting behavior and mechanical properties of melt-spun PE fibers using non-oily/non-toxic liquid baths containing an organic additive. It is observed that higher drag force and interaction between fiber surface and non-oily/non-toxic liquid as ecological spinning liquid with higher dynamic viscosities provided enhanced mechanical properties of the fibers. Increasing the drag force to 0.138 N, resultant fibers exhibited modulus values of about 1 GPa and 1.3 GPa for MDPE and LLDPE, respectively at only 750 m/min take-up speed. Moreover, Arabic Gum (AG) as an organic additive into the liquid enhanced fiber wettability, i.e., water contact angle of 37.8° for MDPE samples. This versatile simple and ecological modified production line is capable of improving hydrophilicity and performance of PE fibers and can facilitate widespread use in composites for medical to defense applications at low manufacturing cost.

Optimal process conditions to recycled polyester dyeing using natural annatto dye

The growing interest in replacing synthetic dyes with natural sources is a result of environmental concern, since natural dyes are less aggressive and more biodegradable. Despite being a sustainable alternative, natural dyes have some limitations. In this context, this paper evaluates the natural annatto dye application in conventional (PES) and recycled polyester (rPES) fabrics, with a view to industrial application. For this purpose, operational parameters (temperature and pH) were varied to achieve the optimum dyeing process condition, regarding the color and quality of fabrics. The temperature oscillated from 98.3 °C to 136.2 °C, while the pH from 4.17 to 9.83 in the liquid bath during dyeing, at a fixed concentration of 1.5% of natural annatto dye, for 60 min. FTIR analysis was performed to characterize the presence of the dye molecule in the dye bath. The dyeing that showed the best results, for the exhaustion (95.6%), KS (2.21) and fastness scores (4/5), was carried out at 115 °C and pH 4.17. The dyed samples showed low light fastness values after 5 h of exposure. Further analysis to show the effect of dyeing time, presented that in 10 min the maximum fabric coloring is reached, with a KS value of 3.58. Also, the color parameters changes of the dye in water solution were evaluated at different pH values. In conclusion, the conditions evaluated for natural annatto dye application presented good dyeability for both fabrics (PES and rPES), demonstrating great potential for use in the textile industry.

Efektivitas Antibakteri Staphylococcus aureus Dari Sediaan Sabun Mandi Cair Dari Ekstrak Etanol Daun Beluntas (Pluchea indica L)

Beluntas leaves (Pluchea indica L.) is one of the plants that contain compounds such as flavonoids, alkaloids, tannins and saponins. This compound can be used to inhibit the growth of Staphylococcus aureus bacteria. The aim of this research is to make liquid bath soap preparation from ethanol extract beluntas leaves (Pluchea indica L.) and to know anthibactery activity against Staphylococcus aureus bacteria. The formula used in making liquid soap ethanol extract beluntas leaves (Pluchea indica L.) made with variation concentration 0%, 3%, 6% and 9%. The activity of extract of liquid soap beluntas leaves against the bacteria staphylococcus aureus by diffusion method using a concentration variation of 0%, 3%, 6% and 9% having the diameter of the inhibition zone respectively 4,48 mm, 6,23 mm and 7,3 mm. Statistical tests using parametic SPSS tests were carried out, the results obtained at concentrations of 6% and 9% had te same diameter inhibition zone, which was included in the category of moderate inhibition zone.

IEEE Transactions on Applied Superconductivity

Non-metallic structural materials that act as an electrical insulation are needed for cryogenic power applications. One of the extensively utilized materials is glass fiber reinforced resins (GFRR) and may also be known as GFRP and FRP. They are created from glass fiber cloth that are impregnated with an epoxy resin under pressure and heat. Although the materials based on GFRR have been employed extensively, reports about their dielectric properties at cryogenic temperatures and larger thicknesses are generally lacking in the literature. Therefore to guide electrical apparatus designers for cryogenic applications, GFRR samples with different thicknesses are tested in a liquid nitrogen bath. Scaling relation between the dielectric breakdown strength and the GFFR thickness is established. Their loss tangents are also reported at various frequencies.

The Stability of a Hydrodynamic Bravais Lattice

We present the results of a theoretical investigation of the stability and collective vibrations of a two-dimensional hydrodynamic lattice comprised of millimetric droplets bouncing on the surface of a vibrating liquid bath. We derive the linearized equations of motion describing the dynamics of a generic Bravais lattice, as encompasses all possible tilings of parallelograms in an infinite plane-filling array. Focusing on square and triangular lattice geometries, we demonstrate that for relatively low driving accelerations of the bath, only a subset of inter-drop spacings exist for which stable lattices may be achieved. The range of stable spacings is prescribed by the structure of the underlying wavefield. As the driving acceleration is increased progressively, the initially stationary lattices destabilize into coherent oscillatory motion. Our analysis yields both the instability threshold and the wavevector and polarization of the most unstable vibrational mode. The non-Markovian nature of the droplet dynamics renders the stability analysis of the hydrodynamic lattice more rich and subtle than that of its solid state counterpart.

Role of Surface Tension in Microrobot Penetration in Membranes.

cell-membrane fusion using microrobots can be a useful technique for delivering bioactive compounds to cellular systems. The role of membrane curvature and lipid ordering in the cell membrane penetration process is well known. However, once the fusion into the cell membrane is already initiated, the fluid dynamics of microrobot penetration based on tension difference of the microrobot solution and membrane curvature at the fusion pore has not been explored yet. Here, we demonstrate how surface tension difference among merging interfaces plays role in microrobot droplet penetration into a liquid bath, mimicking cell membrane fusion. The maximum penetration of a microrobot droplet into a liquid bath depends on the positive difference of surface tension between the droplet and liquid bath, longitudinal curvature of the bridge region, and the size of the droplet.

Portable Heating System Based on a Liquid Metal Bath for Rapid PCR

With the outbreak of COVID-19 around the world, rapid and accurate detection of new coronaviruses is the key to stop the transmission of the disease and prevent and control the novel coronavirus, among which polymerase chain reaction (PCR) is the mainstream nucleic acid detection method. A temperature cycling device is the core of the PCR amplification micro-device. The precision of the temperature control and temperature change rate directly affect the efficiency of PCR amplification. This study proposes a new PCR method based on rapid PCR chip optimization of a liquid metal bath, which realizes precise and rapid temperature rise and fall control. We systematically explored the feasibility of using liquid metals with different melting points in the system and proposed a 47 °C bismuth-based liquid metal bath as the heat conduction medium of the system to optimize the system. The heat conduction properties of the thermally conductive silicone oil bath were compared. Compared with the thermally conductive silicone oil bath, thermal cycle efficiency is improved nearly 3 times. The average heating rate of the liquid metal bath is fast, and the temperature control stability is good, which can significantly reduce the hysteresis, and the temperature change curve is more gentle, which can greatly improve the efficiency of PCR amplification. The results of gene amplification using rat DNA as the template and SEC61A as the target also indicate that the system can be successfully used in PCR devices, and the types of PCR containers can be not limited to PCR tubes. Based on the experiment, we proved that the PCR method optimized by the liquid metal bath multi-gene rapid PCR chip can further improve the temperature response speed. It has the advantages of accurate data, fast response speed, low price, safety, and environmental protection and can effectively reduce the time of PCR and improve the application efficiency. As far as we know, this is the first international report on using a liquid metal bath to do rapid-cooling PCR.

Mechanisms ruling the lifetimes of films of liquid mixtures

Foams and bubbles formed in liquid mixtures have lifetimes longer by several orders of magnitude than in pure liquids of similar viscosities. We have shown recently that this effect results from slight differences in molecular concentrations between bulk and surfaces, which give rise to a thickness-dependent surface tension of liquid films. We present a quantitative description of the enhanced stability of liquid films in binary mixtures, based on experimental data and theoretical analysis. Experiments were performed with mixtures of different natures and compositions: foams of stationary heights were obtained by continuous injection of gas, on one hand, and single bubbles were swollen under the surface of a liquid bath, on the other hand. Remarkably, the lifetimes measured in both experiments exhibit the same variations with mixture composition, and follow a power law with the microscopic length that characterises the amplitude of the thickness-dependent surface tension. In addition, the lifetimes vary with the squared film thicknesses at the onset of bursting. We suggest that two stages occur between the birth of liquid films and their rupture. We show how the thickness-dependent surface tension allows an equilibrium shape to be reached at the end of a first stretching stage. We give an analytical description of this shape, which is fully consistent with experimental findings. We suggest a possible mechanism for final rupture of the film, and discuss it in light of existing theoretical predictions. Finally, we compare the properties of liquid mixtures and surfactant solutions, and in particular their surface rheology.

Poster 105: Nanowarming by Inductive Heating of Vitrified Large Articular Cartilage Specimens, In Vivo Testing with Hanford Mini Pigs

Poster 105: Nanowarming by Inductive Heating of Vitrified Large Articular Cartilage Specimens, In Vivo Testing with Hanford Mini Pigs

A LN2-based cryogenic system prototype for future PandaX experiment

This paper describes results on R&D of an economical and efficient cryogenic system prototype for future liquid xenon detector. The test module of the prototype has a “coldhead” attached to a copper rod, which is specially designed to transport heat loads to a free-boiling liquid nitrogen bath. The performance of the test module and commercial refrigerators is compared. The module with an optimized copper rod has demonstrated more than 1500 W cooling power at 178 K. The temperature of the “cold head” can be kept stable with an error of 0.02 K, its fluctuation is within 0.1 K.

Physical characteristic and antioxidant activities of liquid bath soap with substitution of β-carotene crude extract from Gracilaria sp.

Synthetic antioxidant BHT is widely used in bath soap products as an antioxidant and prevents rancidity in bath soaps, but BHT is harmful to the skin if the addition is excessive. So we need natural antioxidants that can replace the role of BHT as an antioxidant. The purpose of this study was to determine the effect of substitution of BHT with β-carotene Gracilaria sp. on the physical properties of liquid bath soap and determine the best concentration of BHT substitution with β-carotene Gracilaria sp. added to liquid bath soap formulations. This study used a completely randomized design (CRD) consisting of 3 substitution treatments for BHT with β-carotene, namely (1g BHT : 0g β-carotene), (0,5g BHT : 0,5g β-carotene), and (0g BHT : 1g β-carotene) in 100 ml of liquid soap, with 6 repetitions each. Parameters observed were pH, foam stability, viscosity, hedonic, physical stability, and antioxidant activity. The results of this study the substitution of β-carotene Gracilaria sp. the liquid bath soap had a significant effect (p<0.05) on the pH parameter and no significant effect (p<0.05) on the foam stability test and viscosity test parameters. Based on the hedonic test value, soap with the addition of 0,5 g BHT: 0,5g β-carotene has the highest test value to produce the best quality soap.

Technological basis for the process of application of diffusion coatings in liquid metal melts with use of electric furnaces with air atmosphere

Diffusion saturation of the components surfaces in the melts of low-melting metals is the most efficient among known technologies for application of coatings from a liquid phase. However, as soon as this technology is realized at present time with use of special units with protective media, it restricts principally its wide practice. This work presents the results of examination of application processes for diffusion coatings in the melts of low-melting metals using electric furnaces with air atmosphere. Use of this process in shaft or muffle furnaces, which are widely applied at the modern machine-building production facilities, means introduction of the important innovations in the existing technology due to the effect of electric furnace oxidizing medium on quality of obtained coatings. Thereby two following aims of the conducted investigations were formulated: comprehensive study of coatings forming regularities with use of liquid metal melts in the conditions of oxidizing effect in electric furnaces with air atmosphere, as well as development of practical recommendations for elimination of harmful influence of high-temperature oxidation of melt and processing product on quality of coatings. Testing of suggested technological routes for forming of diffusion metallic coatings on steel products in low-melting metal melts using electric furnaces with air atmosphere is an actual problem. Protection of final melt and product surface from oxidation using different fluxes is proposed. Use of the mix of NaCl-Na2CO3 salts didn&rsquo;t provide protection of liquid metal bath and steel product surface from high-temperature oxidation. Use of Na2B4O7 as a protective flux also didn&rsquo;t provide efficient protection from high-temperature oxidation, because porous inhomogeneously distributed diffusion nickel coating with thickness 9-10 &mu;m was obtained. The best result was achieved using CaO-Li2CO3-B2O3 flux. As a result, single-layered, uniform, porous-free, homogeneously distributed diffusion nickel coating with thickness 20-22 &mu;m was obtained.