scholarly journals Thermal Analyses of Nanowarming-Assisted Recovery of the Heart From Cryopreservation by Vitrification

2021 ◽  
Author(s):  
Purva Joshi ◽  
Lili Ehrlich ◽  
Zhe Gao ◽  
John Bischof ◽  
Yoed Rabin

Abstract This study explores thermal design aspects of nanowarming-assisted recovery of the heart from indefinite cryogenic storage, where nanowarming is the volumetric heating effect of ferromagnetic nanoparticles excited by a radio-frequency electromagnet field. This study uses computation means, while focusing on the human heart and the rat heart models. The underlying nanoparticle loading characteristics are adopted from a recent, proof-of-concept experimental study. While uniformly distributed nanoparticles can lead to uniform rewarming, and thereby minimize adverse effects associated with ice crystallization and thermomechanical stress, the combined effects of heart anatomy and nanoparticle loading limitations present practical challenges which this study comes to address. Results of this study demonstrate that under less-than-ideal conditions, nonuniform nanoparticles warming may lead to a subcritical rewarming rate in some parts of the domain, excessive heating in others, and increased exposure potential to cryoprotective agents (CPAs) toxicity. Nonetheless, results of this study also demonstrate that computerized planning of the cryopreservation protocol and container design can help mitigate the associated adverse effects, with examples relating to adjusting the CPA and/or nanoparticle concentration, and selecting heart container geometry and size. In conclusion, nanowarming provides superior conditions for organ recovery from cryogenic storage, which comes with an elevated complexity of protocol planning and optimization.

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
David P. Eisenberg ◽  
John C. Bischof ◽  
Yoed Rabin

This study focuses on thermomechanical effects in cryopreservation associated with a novel approach of volumetric heating by means on nanoparticles in an alternating electromagnetic field. This approach is studied for the application of cryopreservation by vitrification, where the crystalline phase is completely avoided—the cornerstone of cryoinjury. Vitrification can be achieved by quickly cooling the material to cryogenic storage, where ice cannot form. Vitrification can be maintained at the end of the cryogenic protocol by quickly rewarming the material back to room temperature. The magnitude of the rewarming rates necessary to maintain vitrification is much higher than the magnitude of the cooling rates that are required to achieve it in the first place. The most common approach to achieve the required cooling and rewarming rates is by exposing the specimen's surface to a temperature-controlled environment. Due to the underlying principles of heat transfer, there is a size limit in the case of surface heating beyond which crystallization cannot be prevented at the center of the specimen. Furthermore, due to the underlying principles of solid mechanics, there is a size limit beyond which thermal expansion in the specimen can lead to structural damage and fractures. Volumetric heating during the rewarming phase of the cryogenic protocol can alleviate these size limitations. This study suggests that volumetric heating can reduce thermomechanical stress, when combined with an appropriate design of the thermal protocol. Without such design, this study suggests that the level of stress may still lead to structural damage even when volumetric heating is applied. This study proposes strategies to harness nanoparticles heating in order to reduce thermomechanical stress in cryopreservation by vitrification.


Aerospace ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 150
Author(s):  
Yeon-Kyu Park ◽  
Geuk-Nam Kim ◽  
Sang-Young Park

The CANYVAL-C (CubeSat Astronomy by NASA and Yonsei using a virtual telescope alignment for coronagraph) is a space science demonstration mission that involves taking several images of the solar corona with two CubeSats—1U CubeSat (Timon) and 2U CubeSat (Pumbaa)—in formation flying. In this study, we developed and evaluated structural and thermal designs of the CubeSats Timon and Pumbaa through finite element analyses, considering the nonlinearity effects of the nylon wire of the deployable solar panels installed in Pumbaa. On-orbit thermal analyses were performed with an accurate analytical model for a visible camera on Timon and a micro propulsion system on Pumbaa, which has a narrow operating temperature range. Finally, the analytical models were correlated for enhancing the reliability of the numerical analysis. The test results indicated that the CubeSats are structurally safe with respect to the launch environment and can activate each component under the space thermal environment. The natural frequency of the nylon wire for the deployable solar panels was found to increase significantly as the wire was tightened strongly. The conditions of the thermal vacuum and cycling testing were implemented in the thermal analytical model, which reduced the differences between the analysis and testing.


Author(s):  
Jun Su Park ◽  
Namgeon Yun ◽  
Hokyu Moon ◽  
Kyung Min Kim ◽  
Sin-Ho Kang ◽  
...  

This paper presents thermal analyses of the cooling system of a transition piece, which is one of the primary hot components in a gas turbine engine. The thermal analyses include heat transfer distributions induced by heat and fluid flow, temperature, and thermal stresses. The purpose of this study is to provide basic thermal and structural information on transition piece, to facilitate their maintenance and repair. The study is carried out primarily by numerical methods, using the commercial software, Fluent and ANSYS. First, the combustion field in a combustion liner with nine fuel nozzles is analyzed to determine the inlet conditions of a transition piece. Using the results of this analysis, pressure distributions inside a transition piece are calculated. The outside of the transition piece in a dump diffuser system is also analyzed. Information on the pressure differences is then used to obtain data on cooling channel flow (one of the methods for cooling a transition piece). The cooling channels have exit holes that function as film-cooling holes. Thermal and flow analyses are carried out on the inside of a film-cooled transition piece. The results are used to investigate the adjacent temperatures and wall heat transfer coefficients inside the transition piece. Overall temperature and thermal stress distributions of the transition piece are obtained. These results will provide a direction to improve thermal design of transition piece.


2018 ◽  
Author(s):  
Milica Markovic ◽  
Juliana Alves Americo ◽  
Inês Julia Ribas Wajsenzon ◽  
Yasmin Rodrigues da Cunha ◽  
Thaísa Vieira Santos de Souza ◽  
...  

Background. Insufficient quantities of freshly harvested Limnoperna fortunei gametes and embryos constrain reproduction research in the laboratory. Cryopreservation would allow the accumulation and storage of gametes when they are available. The lack of available cryopreservation protocol for Limnoperna fortunei in the literature led our research group to undertake a study to establish which cryoprotective agents can be might be most useful for cryopreservation of this species’ sperm. Methods. 2%, 5%, and 10% concentration of ethylene glycol, dimethyl sulfoxide, glycerol, and polyethylene glycol 4000 as well as 0.2 M glucose, sucrose, and trehalose (mixed into the 10% concentration of the aforementioned agents) were tested in a 1:1 ratio with sperm, in 0.25 ml straws, frozen in liquid nitrogen. Results. After 48 hours the best survival rate was in the samples with 10% polyethylene glycol 4000, 36.1%, which also resulted in viable sperm after 7 and 15 days.


2018 ◽  
Author(s):  
Milica Markovic ◽  
Juliana Alves Americo ◽  
Inês Julia Ribas Wajsenzon ◽  
Yasmin Rodrigues da Cunha ◽  
Thaísa Vieira Santos de Souza ◽  
...  

Background. Insufficient quantities of freshly harvested Limnoperna fortunei gametes and embryos constrain reproduction research in the laboratory. Cryopreservation would allow the accumulation and storage of gametes when they are available. The lack of available cryopreservation protocol for Limnoperna fortunei in the literature led our research group to undertake a study to establish which cryoprotective agents can be might be most useful for cryopreservation of this species’ sperm. Methods. 2%, 5%, and 10% concentration of ethylene glycol, dimethyl sulfoxide, glycerol, and polyethylene glycol 4000 as well as 0.2 M glucose, sucrose, and trehalose (mixed into the 10% concentration of the aforementioned agents) were tested in a 1:1 ratio with sperm, in 0.25 ml straws, frozen in liquid nitrogen. Results. After 48 hours the best survival rate was in the samples with 10% polyethylene glycol 4000, 36.1%, which also resulted in viable sperm after 7 and 15 days.


2004 ◽  
Vol 1 (1) ◽  
pp. 1-8 ◽  
Author(s):  
G. Hanreich ◽  
M. Mayer ◽  
M. Mündlein ◽  
J. Nicolics

The lower thermal conductivity of gallium arsenide (GaAs) compared to silicon (Si) requires a careful thermal design for optimizing device performance and reliability. In this paper a recently developed thermal simulation tool (TRESCOM II) is applied for investigating the thermal behavior of a heterojunction GaAs power field effect transistor (FET). Main features of the simulation tool are an easy model creation procedure and an efficient numerical solver. Moreover, the tool allows to consider temperature dependent material properties and temperature dependent boundary conditions. The investigation of the thermal behavior of the power transistor has two goals. First goal is to establish the temperature distribution within the active layer of the FET to allow predictions of thermal-electrical interactions. A deeper insight into thermal-electrical interaction will lead to better equivalent circuit models used in electrical circuit design. Due to the fact that reliability of the component is mainly determined by thermal load and induced thermomechanical stress, second goal of this work is to investigate the influence of chip thickness and die bonding variations on the thermal behavior. Thermal response on different power levels is investigated and the influence of chip thickness tolerances and die bonding on the thermal performance of the device is discussed.


2018 ◽  
Author(s):  
Milica Markovic ◽  
Juliana Alves Americo ◽  
Inês Julia Ribas Wajsenzon ◽  
Yasmin Rodrigues da Cunha ◽  
Thaísa Vieira Santos de Souza ◽  
...  

Background. Insufficient quantities of freshly harvested Limnoperna fortunei gametes and embryos constrain reproduction research in the laboratory. Cryopreservation would allow the accumulation and storage of gametes when they are available. The lack of available cryopreservation protocol for Limnoperna fortunei in the literature led our research group to undertake a study to establish which cryoprotective agents can be might be most useful for cryopreservation of this species’ sperm. Methods. 2%, 5%, and 10% concentration of ethylene glycol, dimethyl sulfoxide, glycerol, and polyethylene glycol 4000 as well as 0.2 M glucose, sucrose, and trehalose (mixed into the 10% concentration of the aforementioned agents) were tested in a 1:1 ratio with sperm, in 0.25 ml straws, frozen in liquid nitrogen. Results. After 48 hours the best survival rate was in the samples with 10% polyethylene glycol 4000, 36.1%, which also resulted in viable sperm after 7 and 15 days.


2012 ◽  
Vol 2012 (0) ◽  
pp. _S192011-1-_S192011-5
Author(s):  
Ryota INOUE ◽  
Hiroto OGAWA ◽  
Tsuyoshi TOTANI ◽  
Masashi WAKITA ◽  
Harunori NAGATA

2017 ◽  
Vol 139 (05) ◽  
pp. 44-49
Author(s):  
Yoed Rabin ◽  
Jedediah Lewis

This article focuses on various technological innovations in the field of cryopreservation of human tissues. In order to further explore how engineers from various disciplines can offer a broader and improved set of tools to tackle preservation challenges, ASME and the Organ Preservation Alliance are co-organizing the Summit on Organ Banking through Converging Technologies in Boston, Mass., in August 2017. Techniques for successful cryopreservation have been developed over the past five decades for several tissue types. To achieve vitrification, cryobiologists introduce glass-promoting solutions known as cryoprotective agents (CPAs) into the tissue. As researchers push the boundaries on the ability to cryopreserve bulky tissues and large organs, a new thermal challenge emerges called rapid cooling, which can potentially give rise to dangerous thermomechanical stress driven by the tendency of the material to contract with temperature.


Author(s):  
E. J. J. Beyer ◽  
K. J. Craig

This paper describes the design process followed by Westinghouse Electric South Africa for the insertion of hot internals into the Reactivity Control System (RCS) and Reserve Shutdown System (RSS) Units Under Test (UUTs) at the Helium Test Facility (HTF) at Pelindaba, South Africa. The aim of the UUTs is to allow the validation of the high temperature operation of the RCS and RSS systems for implementation into the proposed Demonstration Power Plant of the PBMR. The units use electrical heaters to obtain pebble-bed reactor thermal conditions for both the control rods and small absorber spheres (SAS) under a pressurized helium environment. Design challenges include providing for strength under elevated temperatures (900°C maximum); pressure boundary integrity (9MPa maximum); separation of different volumes (representing core barrel, reactor citadel and other Reactor Pressure Vessel (RPV) volumes); thermal protection of carbon steel vessels by using thermal insulation; allowing for diverse thermal expansion coefficients of different materials; allowing for depressurization events within the insulation and internals; having access for temperature, pressure, stress and proximity sensors and electrical wiring through high pressure penetrations; and provision for assembly of the hot internals both on and off-site. Several thermal analyses using Computational Fluid Dynamics (CFD) were performed to evaluate both worst-case and operational conditions of the UUTs. Factors that were considered include thermal insulation properties, heat transfer modes (internal radiation, external radiation and natural convection, forced internal convection for cooling) and operating pressure (ranging from 1 to 9MPa). The thermal design uses elements originally proposed for hot gas duct design. The results obtained show that the proposed design satisfies ASME VIII requirements of the pressure boundary and that all challenges are successfully met.


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