Heating Irradiation Research Articles

A simple flash and freeze system for cryogenic time-resolved electron microscopy.

As the resolution revolution in CryoEM expands to encompass all manner of macromolecular complexes, an important new frontier is the implementation of cryogenic time resolved EM (cryoTREM). Biological macromolecular complexes are dynamic systems that undergo conformational changes on timescales from microseconds to minutes. Understanding the dynamic nature of biological changes is critical to understanding function. To realize the full potential of CryoEM, time resolved methods will be integral in coupling static structures to dynamic functions. Here, we present an LED-based photo-flash system as a core part of the sample preparation phase in CryoTREM. The plug-and-play system has a wide range of operational parameters, is low cost and ensures uniform irradiation and minimal heating of the sample prior to plunge freezing. The complete design including electronics and optics, manufacturing, control strategies and operating procedures are discussed for the Thermo Scientific™ Vitrobot and Leica™ EM GP2 plunge freezers. Possible adverse heating effects on the biological sample are also addressed through theoretical as well as experimental studies.

Effects of infrared radiation heating temperature and time on starch gelatinization and technological, thermal, and pasting properties of parboiled rice

AbstractBackground and ObjectivesThe improvement of the physical, chemical, and sensorial parameters of parboiled rice is constantly sought by the industry. Thus, the objective was to evaluate the effects of infrared radiation heating temperature (80°C, 100°C, 120°C, and 140°C) and time (2, 6, 10, and 14 min) on starch gelatinization and technological, thermal, and pasting properties of parboiled rice.FindingsThe degree of gelatinization of rice starch subjected to infrared radiation heating ranged from 5.73% to 39.13% and the relative crystallinity from 49.70% to 42.30% in the treatments at 80°C for 6 min and 140°C for 14 min, respectively. The increase in head rice yield is related to an increase in the degree of gelatinization and a reduction in the relative crystallinity of the starch, making the grains more resistant to breakage. There was a tendency to reduce the cooking time at temperatures of 80°C and 140°C, regardless of the heating time. As for hardness, the opposite behavior was observed, with a tendency to increase at temperatures of 80°C and 140°C, regardless of the heating time.ConclusionsInfrared radiation heating can be used to produce parboiled rice. It is recommended to use temperatures between 100°C and 120°C for 6–10 min.Significance and NoveltyThe method validated in this study presented to the rice processing industry a new way to produce parboiled rice. The study showed that it is possible to use infrared radiation heating to gelatinize rice starch. The use of infrared radiation in rice processes is widely used in the industry as a source of heating, whether in drying or parboiling, with previous studies showing a reduction of up to 4.6 times in energy consumption compared to conventional sources of heating.

INFLUENCES OF TEMPORAL AND SPATIAL DISTRIBUTION OF LASER RADIATION HEAT ON THE CRACK PROPAGATION FOR CUTTING HIGH THICK MATERIALS

The temporal and spatial distribution of irradiated heat on the material surface will affect the temperature gradient of the heated area and subsequently change the stress field distribution inside the material. To this end, the influence mechanisms of spatial and temporal distribution on the internal temperature and stress fields are deeply investigated numerically. The influence of laser process parameters on the stress field of internal material along the cutting path is also revealed. The simulation results show that as the laser radiation area increases, the tensile stress concentration area on the material surface will extend from the surface to the thickness. The stress gradient and extreme value inside the material irradiated by elliptical spot laser are larger than that by circular spot laser. Compared with the single laser, the stress and temperature on the whole profile of the material irradiated by double-sided asymmetric simultaneous laser are symmetrical. At the same time, high tensile stress areas in front of the laser spot on the upper and lower surfaces gradually extended to the middle area along the thickness direction. This results in the crack formation in the middle, propagation on the upper and lower surfaces, faster crack extension speed, and less delay fracture than that of a single laser. The results will contribute to controlling the maximum tensile stress perpendicular to the scanning path to expand along the thickness direction and will realize rapid thermal stress-controlled fracture cutting of high thick materials.

Accounting for environmental stress in restoration of intertidal foundation species

Abstract Restoration of foundation species in historical habitat may be difficult if adult facilitation is obligatory for survival of early life stages. On intertidal Mediterranean coasts, large‐scale loss of the dominant forest‐forming macroalga Ericaria amentacea have prompted restoration efforts using recruits. Yet, early life stages may be more susceptible to the abiotic stress that characterizes their habitat. We tested strategies to enhance resilience of lab‐cultured juveniles of E. amentacea to environmental stress in historical habitat lacking conspecifics. Juveniles were exposed in culture to fluctuations of the dominant physical stressors, irradiance and temperature, and then outplanted in upper and lower zones of their native intertidal range. Without adult canopy, juvenile outplant survival was limited to the lower tidal range, with nearly complete mortality in the upper zone. Survival was also strongly determined by spatial clumping of recruits within the outplant substrate. Longer‐term growth in the lower zone was enhanced by fluctuating mild stress in culture, with variable irradiance and concurrent heat pulses increasing post‐outplant cover by 40%–60% after 4 months. Clumping also promoted growth across experimental treatments. Synthesis and applications. Reliance on self‐facilitation feedbacks is a common barrier to foundation species restoration in high‐stress habitats. Our results suggest that without adult habitat amelioration, environmental stress limits recruit survival in intertidal algal forest. Yet, exposure to transient, low environmental stress in culture and outplanting of clumped individuals may confer resilience and allow successful establishment of early life stages in zones of reduced abiotic stress, providing a source for gradual colonization of more high‐stress areas.

Self‐Healing, Photothermal‐Responsive, and Shape Memory Polyurethanes for Enhanced Mechanical Properties of 3D/4D Printed Objects

AbstractAdditive manufacturing is a promising technology that can directly fabricate structures with complex internal geometries, which is barely achieved by traditional manufacturing. However, the mechanical properties of fused deposition modeling (FDM)‐printed objects are inferior to those of conventionally manufactured products. To improve the mechanical properties of the printed products, a series of novel thermoplastic polyurethanes with self‐healing properties, intrinsic photothermal effects, and excellent printability are designed and synthesized by introducing dynamic oxime–carbamate bonds and hydrogen bonds into the polymer chains. On‐demand introduction of near‐infrared (NIR) irradiation, direct heating, and sunlight irradiation enhances interfacial bonding strength and thus improve the mechanical properties of the printed product. Additionally, mechanical anisotropy of the printed products can be sophistically manipulated by regulating the self‐healing conditions. Support‐free printing and healing of damaged printed products are also achieved owing to the self‐healing properties of the material. Moreover, the as‐prepared materials exhibit shape‐memory properties NIR irradiation or direct heating effectively triggers shape‐memory recovery and demonstrates their potential in 4D printing by printing a man‐like robot. This study not only provides a facile strategy for obtaining high‐performance printed products but also broadens the potential applications of FDM technology in intelligent devices.

Microwave- and Thermally Promoted Iminyl Radical Cyclizations: A Versatile Method for the Synthesis of Functionalized Pyrrolines.

A detailed study of iminyl radical cyclizations of O-aryloximes tethered to alkenes is reported. The reactions can be triggered by either microwave irradiation or conventional heating in an oil bath. A variety of radical traps can be employed, enabling C-C, C-N, C-O, C-S, or C-X bond formation and producing a diverse array of functionalized pyrrolines. Substrates containing an allylic sulfide furnish terminal alkenes by a tandem cyclization-thiyl radical β-elimination pathway. Cyclizations of hydroxylated substrates exhibit moderate diastereoselectivity that in some cases can partially be attributed to intramolecular hydrogen bonding. Computational studies suggested a possible role for thermodynamics in controlling the stereochemistry of cyclizations. The reaction temperature can be lowered from 120 to 100 °C by employing O-(p-tert-butylphenyl)oximes instead of O-phenyloximes as substrates, and these second-generation iminyl radical precursors can be used in a one-pot oxime ether formation-cyclization that is promoted by conventional heating. The functionalized pyrrolines obtained from these reactions can be conveniently transformed in several different ways.

Sub-ambient cooling effect and net energy efficiency of a super-amphiphobic self-cleaning passive sub-ambient daytime radiative cooling coating applied to various buildings

In this study, a super-amphiphobic passive sub-ambient daytime radiative cooling (PSDRC) coating was applied to various buildings in different climatic regions in China. Irrespective of sunny, cloudy, and rainy weather conditions, the roof and west-facing wall surfaces coated with the PSDRC coating exhibited distinct sub-ambient cooling effects. Compared with the cool-white and grey roof surface temperatures, the roof surface temperature due to PSDRC coating was lower by 10.1 °C and 33.1 °C, respectively. Consequently, the room interior temperatures of different buildings were lower than the ambient air temperature during the day because of heat conduction and convection. The room with a window coated by the PSDRC coating had 18.2 °C lower interior temperature than that with a west-facing glass window. Thus, the PSDRC coating decreased the cooling energy consumption of buildings in the summer but increased the heating energy consumption in the winter. However, the net energy savings were considerable because of low solar irradiance and high heating energy demand when the sub-ambient cooling effect was diminished, which minimised the difference between the roof surface and room interior temperatures of the PSDRC and control buildings. After five-cycle dirt resistance tests, the solar reflectance of the super-amphiphobic PSDRC coating was reduced only by 0.0051. After 2000 h of artificial accelerated weathering tests, the solar reflectance of the superamphiphobic PSDRC coating was attenuated by 0.021 on average. This indicates the significance of the super-amphiphobic self-cleaning capability, which endowed the coating with a long-term sub-ambient cooling effect.

Comparison of microwave irradiation and conventional thermal heating on volatile profiles and degree of oxidation in corn oil

SummaryVolatile profiles and degree of oxidation in corn oils after microwave treatment for 50 min were compared to oils with conventional heating at 180°C for 4 h. Oil microwaved for 10 and 50 min showed a similar degree of oxidation compared to the oil heated at 180°C for 1 and 3 h, respectively, based on the primary and secondary oxidation products. However, the total volatile contents of 50 min‐microwaved oil were significantly lower than that of corn oil heated for 1 h at 180°C (P < 0.05). Microwave treatment accelerated the rates of lipid oxidation by 4.6 times compared to 180°C thermal oxidation. Relatively short treatment with microwave irradiation may not provide sufficient time to generate volatiles from oil. Microwaved corn oil for 50 min had higher contents of hexanal and t‐2‐heptenal and lower contents of 2,4‐decadienal and nonanal than the oils heated at 180°C for 3 h. Reactive oxygen species may be involved in volatile formation in microwave‐irradiated oils.

Verification of Bison fission product species conservation under TRISO reactor conditions

When assessing the reliability and predictive capabilities of a simulation tool, code verification is used to ensure that the implemented numerical algorithm is a faithful representation of its underlying mathematical model, including partial differential or integral equations, initial and boundary conditions, and auxiliary relationships. During this process, numerical results in a discrete solution are compared to the analytical solution of the mathematical model. In this paper, the code verification process is applied to one-dimensional spatiotemporal problems that exercise partial differential equation governing the conservation of fission product species (or mass diffusion). Numerical experiments were performed in the Bison fuel performance code to evaluate its predictive capability under various TRISO reactor conditions such as base irradiation and safety heating test conditions for either short- or long-lived fission product species, as well as a case concerning evaporation from the outer surface of a particle. The code predictions were compared with the expected exact results obtained from the analytical expressions, and the fact that they demonstrate the correct analytical behavior provides strong evidence of proper numerical algorithm implementation.

How to Reduce the Flammability of Plastics and Textiles through Surface Treatments: Recent Advances

The high flammability of plastics, polymer composites, textiles, and foams represents a severe and stringent issue that significantly limits their use in all those sectors, where resistance to a flame or an irradiative heat flux is mandatory [...]

Assessment of seasonal Borehole Thermal Energy Storage in the seawater intrusion region of a carbonate aquifer

In coastal areas the seawater intrusion region underlying freshwater aquifers represents a low quality but wide and deep geo resource. Seasonal thermal energy storage and recovery is an important component of district heating and cooling system to manage renewable energy fluctuations, such as solar irradiance or waste heat from industrial processes, and the corresponding mismatch of thermal energy demand and supply. A numerical tool to evaluate the performance of seasonal Borehole Thermal Energy Storage (BTES) system to store and recover solar energy in the seawater intrusion region, underlying the shallow freshwater aquifer and with thermally and hydraulically insulated upper borehole section is developed and applied to the coastal carbonate aquifer of the metropolitan area of Bari (Italy). The hourly thermal demand of the University Sport Centre of Bari is used as benchmark. The design and performance of the BTES system is strongly dependent on the geological and hydrogeological context as well as on the environmental and operational conditions. The aquifer characterization suggests to locate BTES zone at a depth higher than 100 m from the freshwater – saltwater interface where carbonate unit appears less fractured and karstified showing a value of bulk permeability less than 10−12 m2 and the groundwater flow is slow (∼10−3 md−1). Rayleigh number criterion is used as constraint to determine the maximum heat storage temperature (∼70°C) in order to preserve the lateral thermal stratification and the thermal impact on the shallow freshwater resource. A novel mathematical and computational model is developed to help the design of BTES system and to evaluate its efficiency. The results indicate that the thermal losses within thermally insulated zone influence the effective thermal recovery factor which, according to the baseline scenario, is equal to 47% after five years of operation. The heat energy production of the solar heating system, covers the heat demand with percentage range of 79–117%. The location of BTES in deep seawater region attenuates the decreases of efficiency due to the groundwater flow which became significant at specific discharge around 10−2 md−1. Changing the operation schedule with a shorter heating storage period increases the thermal recovery factor of the BTES of 11.19% after five years of operation, but at the same time the trend of the heat energy production shows a surplus during the midseason and deficit during the winter and summer season respect to the thermal demand. Great care must be taken on the maximum heat storage temperature. A low heat storage temperature ensures a wider safety margin with regards to the thermal stratification and the thermal impact on the shallow aquifer. Anyway, a decrease of 10°C on the maximum heat storage temperature produces a deficit of the heat production respect to the thermal demand in the range of 15%–21%.

Effects of Radiative Diffusion on Dynamical Corotation Torque in Three-dimensional Protoplanetary Disks

The dynamical corotation torque arising from the deformation of horseshoe orbits, along with the vortensity gradient in the background disk, is important for determining the orbital migration rate and direction of low-mass planets. Previous two-dimensional studies have predicted that the dynamical corotation torque is positive, decelerating inward planet migration. In contrast, recent three-dimensional studies have shown that buoyancy resonance makes the dynamical corotation torque negative, accelerating inward migration. In this paper, we study the dependence of the dynamical corotation torque on thermal transport, using three-dimensional simulations. We first show that our results are consistent with previous three-dimensional studies when the disk is fully adiabatic. In more realistic radiative disks, however, radiative diffusion suppresses buoyancy resonance significantly, especially in high-altitude regions, and yields a positive dynamical corotation torque. This alleviates the issue of rapid migration being caused by the negative dynamical corotation torque in adiabatic disks. Our results suggest that radiative diffusion, together with stellar irradiation and accretion heating, are needed to accurately describe the migration of low-mass planets.

Theoretical and Experimental Assay of Shock Experienced by Yeast Cells during Laser Bioprinting.

Laser-induced forward transfer (LIFT) is a useful technique for bioprinting using gel-embedded cells. However, little is known about the stresses experienced by cells during LIFT. This paper theoretically and experimentally explores the levels of laser pulse irradiation and pulsed heating experienced by yeast cells during LIFT. It has been found that only 5% of the cells in the gel layer adjacent to the absorbing Ti film should be significantly heated for fractions of microseconds, which was confirmed by the fact that a corresponding population of cells died during LIFT. This was accompanied by the near-complete dimming of intracellular green fluorescent protein, also observed in response to heat shock. It is shown that microorganisms in the gel layer experience laser irradiation with an energy density of ~0.1–6 J/cm2. This level of irradiation had no effect on yeast on its own. We conclude that in a wide range of laser fluences, bioprinting kills only a minority of the cell population. Importantly, we detected a previously unobserved change in membrane permeability in viable cells. Our data provide a wider perspective on the effects of LIFT-based bioprinting on living organisms and might provide new uses for the procedure based on its effects on cell permeability.

Pd-Supported Co3O4/C Catalysts as Promising Electrocatalytic Materials for Oxygen Reduction Reaction

This paper describes the activity of PdCo3O4/C obtained by wet impregnation towards the oxygen reduction reaction (ORR). For this purpose, the Co3O4/C substrate was synthesized using the microwave irradiation heating method with further annealing of the substrate at 400 °C for 3 h (Co3O4/C-T). Then, the initial Co3O4/C substrate was impregnated with palladium chloride (Pd-Cl2-Co3O4/C), and then part of the obtained Pd-Cl2-Co3O4/C catalyst was annealed at 400 °C for 3 h (PdOCo3O4/C). The electrocatalytic activity of the prepared catalysts was investigated for the oxygen reduction reaction in alkaline media and compared with the commercial Pt/C (Tanaka wt. 46.6% Pt) catalyst. It was found that the annealed PdOCo3O4/C catalyst showed the largest ORR current density value of −11.27 mA cm−2 compared with Pd-Cl2-Co3O4/C (−7.39 mA cm−2) and commercial Pt/C (−5.25 mA cm−2).

Thin-layer drying characteristics, modeling and quality attributes of tomato slices dried with infrared radiation heating

An Infrared dryer was used to examine the drying of tomato slices. In this investigation, the influence of infrared radiation (IR) on the rate of drying, physical quality, energy combustion of tomato was estimated at three different levels of intensity at 0.15, 0.20, and 0.35 W/cm² under different air flows of 0.5, 1, and 1.5 m/s. Tomato slices were dried with an initial moisture content of 19.7 to 0.17 g water/g dry solids by infrared drying. The moisture content and drying rates are found to be dramatically affected by infrared density. An increase in the drying rate and a decrease in the drying period occurred with increasing infrared intensity. A decrease in energy consumption was detected with the increase of radiation intensity. The results clarified that the shrinkage ratio increased with increasing infrared intensity. The rehydration ratio raised with the increase in radiation intensity. The change in the colour difference of dried slices increased with an increase in radiation intensity. The models were in comparison using (R²) coefficient of determination, modelling efficiency (EF), and (χ²) reduced chi-square. Midilli model was fit for simulation of all drying conditions and could be used to estimate tomato moisture content at any time during the infrared drying process.

Flame retarded polymer systems based on the sol-gel approach: recent advances and future perspectives

AbstractThe ease of flammability of polymers represents a key issue that limits their applications in different advanced sectors. In this context, a reliable and effective solution regards the use of flame retardants, i.e., additives that are able to slow down (or even stop) the flame propagation and to enhance the resistance to an irradiative heat flux. Among the different flame retardants designed, synthesized, and applied up-to-now, the utilization of inorganic particles, inorganic and hybrid organic-inorganic coatings has gathered a great interest from either the academic and industrial community, as these structures can provide remarkable flame retardant features to different polymer systems, in which they are embedded or applied onto. In particular, the in situ generation (through sol-gel processes, i.e. hydrolysis and condensation reactions from tailored alkoxide precursors) of ceramic phases, either in the form of particles or as surface coatings, has clearly demonstrated its effectiveness in creating a physical barrier that limits the degradation of the polymer when subjected to the application of a flame or an irradiative heat flux. It also lowers the heat and mass transfer from the degrading polymer to the surroundings and vice versa, hence providing an overall enhancement of heat and fire resistance. This review work seeks to provide an up-to-date overview of the most recent advances in the use of sol-gel methods for conferring flame retardant features to bulk polymers, cellulosic textiles (cotton), and polymer foams. In addition, the current limitations and the potential progresses of these approaches are discussed.

Precise prediction of photothermally induced irreversible bending deformation based on non-uniform thermal expansion of layer-structure films

Although photothermally induced self-bending films based on nonuniform thermal expansion are created, heat transfer and shape-deformation procedures are not investigated very well, limiting the understanding of such complicated behavior and the achievement of precise shape control. Here, thermally expanded microspheres (TEMs) were added into polydimethylsiloxane (PDMS) to create active layers as PDMS-TEM single-layer films that were attached onto pure PDMS passive layer to create PDMS/PDMS-TEM bi-layer films subsequently. After heating, TEMs in the film undergo phase transition and present irreversible thermal expansion, driving deformation of films. Combined with steady-state (uniform heating) deformation simulations and experiments, a deformation model was established before a non-steady state (light irradiation) heat transfer model was set up to simulate the heat transfer process of films under light irradiation. Then the temperature distribution was coupled with the deformation model to simulate the photothermally induced deformation of the samples. The PDMS-TEM single-layer films also presented bending deformation under illumination due to the non-uniform thermal expansion caused by temperature gradient. For bi-layer films, different degrees of thermal expansion between two layers lead to bending deformation. The films with TEM concentration of 30 wt% can achieve great deformation, and the bending curvature was 0.07 mm−1. The geometric parameters including thickness, layer thickness ratio and aspect ratio had little effect on deformation degrees of the films. Deformation mode was varied with aspect ratio. A long side bending and diagonal bending were achieved in bi-layer films at aspect ratios of 7:1 and 1:1. In combination with experimental results, the heat transfer model and deformation model were constructed to demonstrate the complex deformation process, which provides guidance for the structural design of the photothermally induced shape-changing films in practical applications.

ASSESSING LAND SURFACE TEMPERATURE IN URBAN AREAS USING OPEN-SOURCE GEOSPATIAL TOOLS

Abstract. Land surface temperature (LST) in urban areas can be traditionally observed by thermal remote sensors. The increasing availability of 3D city models provides an alternative approach based on geospatial modeling. Using solar radiation tools and scripting in GRASS GIS, we have developed a physically-based LST model that can be used to estimate LST in urban areas represented by vector 3D city models. It uses standard input parameters such as solar irradiance, albedo or convection heat transfer coefficient for urban surfaces. The solar irradiance is estimated using the v.sun solar radiation add-on module in GRASS GIS. The LST values are calculated using map algebra operations using a Python script. The suggested methodology was applied to the study area in the city of Košice, Slovakia. Results indicate that urban morphology has a strong impact on spatial distribution of LST during the daylight hours. The accurate parameterization of urban surfaces can increase the accuracy of the model that can be used for urban planning, optimization of energy use in buildings or mitigation of urban heat island effects.

Study on the Heat Absorption Coefficient of Tungsten as the Plasma-Facing Material for the Upgraded EAST Lower Divertor

Divertor is one of the key plasma-facing components (PFCs) for Experimental Advanced Superconducting Tokamak (EAST) since they play important roles in resisting the energetic particle irradiation and huge heat deposition from the core plasma as well as efficaciously dispelling such energy load. Tungsten is used as the plasma-facing material for PFCs due to the excellent properties. During the thermal analysis and the high heat flux test of the PFCs, the heat absorption coefficient is an important parameter that directly affects the availability and reliability of the design structure. Previous studies have shown that there is a large deviation in the measured heat absorption coefficient of tungsten. Therefore, it is very important to accurately measure the heat absorption coefficient of tungsten. In this article, the heat absorption coefficient of tungsten was tested by the e-beam device of the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). In this test, 36 sets of inlet and outlet water temperature data were obtained by changing the water flow rate and the incident heat flux. The heat absorption coefficient of tungsten was calculated by the theoretical calculation using water calorimetry. The results indicate that the heat absorption coefficient of tungsten is stable at ~0.54, which can be used as a reference for the engineering design of PFCs of the upgraded EAST lower divertor. All test parameters for EAST will provide important reference and guidance to the next-generation fusion facility China Fusion Engineering Test Reactor (CFETR).

Intensifying the co-production of vapor and salts by a one-way brine-flowing structure driven by solar irradiation or waste heat

Interfacial evaporation technology holds great promise in seawater desalination with zero liquid discharge. Here, a salt-extraction evaporator enabling high-productivity co-generation of vapor and salts is designed by combining a one-way brine-flowing evaporation structure with solar irradiation or waste heat. A highly scalable thermo-evaporative structure, prepared by growing polypyrrole (PPy) onto glass fiber (PPy-GF), is employed for investigations. Modeling tools are further developed to guide the rational geometric design of the evaporator based on PPy-GF. This merit also allows us to investigate the complex effects of salt concentration and ionic species on the evaporation-salt generation behaviors to achieve intensified site-specific co-production of vapor and salts. Specifically, this evaporator enables the concentrated seawater to evaporate at an average evaporation rate of 1.12 kg m−2 h−1 and simultaneously produces 4.21 g of salts in 24 h under 1 sun. In addition, the stable evaporation rate of 2.58 kg m−2 h−1 and a salt production amount of 12.92 g in the concentrated seawater are obtained under 60 °C in continuous 30 h. This study is believed to provide a novel avenue for stable and efficient seawater desalination with zero liquid discharge.