Vacuum Heat Research Articles

Strategi Pengembangan Kemasan Berbasis Kualitas Untuk Produk Ikan: Studi Implementasi di Desa Tlesah, Pamekasan

This study aims to evaluate quality-based packaging development strategies for fish products in Tlesah Village, Tlanakan Sub-district, Pamekasan Regency. The applied packaging uses vacuum heating and thermal coating technology to improve the freshness and shelf life of fish products. The research methodology included a qualitative design with a comprehensive assessment of the existing packaging conditions, application of the new technology, and evaluation of the results through laboratory tests and market surveys. The results showed that the new packaging increased the shelf life of fish products by 30%, with a 40% reduction in trimethylamine (TMA) levels compared to the old packaging. Consumer surveys revealed a 90% increase in satisfaction, and sales data showed a 25% increase in product sales with the new packaging. Challenges included initial costs for packaging materials and technology, and the need for external support. The research suggests continuous improvements in packaging techniques and materials and provides practical recommendations for processor groups and stakeholders. Implications for future research include exploring factors of packaging adoption in different contexts and developing innovations in environmentally friendly packaging materials.

Transformation of Metal-Organic Framework from Kinetic to Thermodynamic Product for Controlled Delivery of Vitamin C.

A biocompatible metal-organic framework (MOF), named HSTC-4, constructed using the flexible 4,4'-oxybis(benzoic acid) (OBA), was developed to enable efficient loading and controlled release of vitamin C (VC) through a combination of strategies involving ligand length, structure design, and metal selection. The kinetic product HSTC-4 demonstrates a propensity for transforming into the thermodynamically stable HSTC-5 under external stimuli, such as photoillumination and vacuum heating, as witnessed by single-crystal to single-crystal transformation. Density functional theory (DFT) calculations reveal that the VC guest molecules exhibit stronger binding affinity with HSTC-5 due to its narrower pores compared to HSTC-4, resulting in a slower release of VC from VC@HSTC-5. Furthermore, precise control over VC release can be achieved by introducing surface modifications involving SiO2 onto the structure of VC@HSCT-5, while simultaneously adjusting environmental factors such as pH and temperature conditions. Preliminary cell culture experiments and cytotoxicity assays highlight the biocompatibility of HSTC-5, suggesting that it is a promising platform for sustained drug delivery and diverse biomedical applications.

Mg doping induced enhancement of persistent luminescence of ZGGO: Cr3+ nanoparticles for time-gate optical encryption

Herein, ZMGGO:Cr3+ nanoparticles were prepared by incorporating Mg2+ ions into Cr3+-doped zinc gallogermenate nanoparticles through a hydrothermal path in combination with a vacuum heating. The average size of ZMGGO:Cr3+ nanoparticles minishes from 59 to 12 nm with growing Mg2+ concentration. Meanwhile their luminescence intensity at 696 nm of ZMGGO:Cr3+ nanoparticles was only decreased by less than half of that of the undoped nanoparticles due to the decreased particle size after Mg doping. Meanwhile, the integral luminescence intensity of their entire emission band shows an increasing trend with increasing temperature due to the enhanced phonon sideband luminescence at high temperature. More important, it is found that the formation energies associated with Mg′Ga-GaoZn and Zn′Ga-GaoZn defects are −1.2 and 1.69 eV, respectively, suggesting the enhanced afterglow intensity of ZMGGO:Cr3+ can be ascribed to Mg doping leading to the increased number of these anti-site traps. Finally, the dual-level time-gate optical encryption was demonstrated using phosphorescent inks containing ZMGGO:Cr3+ nanoparticles with different afterglow intensities.

Vacuum processing temperature effect on highly coercive recycled NdFeB permanent magnets with Pr-based alloy addition

This study presents a modified method for recycling NdFeB scrap magnets, producing up to 100 kg of recycled sintered NdFeB magnets per batch. By adding a Pr-based alloy to N40H-grade NdFeB scrap and optimizing vacuum sintering and heat treatment conditions, we enhanced the magnetic properties and corrosion resistance of the recycled magnets. Various analyses, including BH Tracer measurements, FE-EPMA, accelerated corrosion tests, and C/N/O content analysis, evaluated differences in magnetic properties, microstructure, corrosion resistance, and impurity content. Optimal recycling involved vacuum sintering at 1085 °C, followed by heat treatments at 900 °C and 470 °C. Recycled magnets with PrCoGa alloy showed superior properties, such as an intrinsic coercivity (iHc) of 1414 kA/m, remanence (Br) of 1.290 T, and a maximum magnetic energy product ((BH)max) of 315.4 kJ/m, meeting N40H standards. Accelerated corrosion tests also indicated enhanced corrosion resistance in recycled magnets with Pr90Co8Ga2 alloy. This research offers a commercially viable approach for NdFeB magnet and rare earth element recycling.

Investigation the effect of surface treatment on the mechanical properties of coating

AbstractThe study analyzed surface treatment's impact on mechanical properties of Fe-based amorphous coatings. Specimens underwent six-hour treatments at 670 and 770 °C using vacuum heat. Results revealed distinct mechanical features in the coating: Vickers hardness reached 755, scanning electron microscope images displayed glassy phases, showcasing good wear resistance and compressive residual stresses at around −55 MPa. A remarkable 122% increase in compressive residual stress was noted through combined vacuum heat treatment and sandblasting. Volume wear decreased from the initial 18 to 14 mm3 after treatment at 670 °C followed by sandblasting, indicating a 30% enhancement in wear resistance. Yet, using vacuum heat treatment at 770 °C negatively impacted the coating's properties.

Uniformizing the temperature of turbine blades during the heat treatment process from the perspective of radiation energy distribution

Nickel-based single-crystal turbine blades are critical components of jet engines. Due to element segregation and microstructural defects in as-cast blades, vacuum heat treatment is essential. Controlling the blades’ heat treatment temperature is crucial for improving mechanical performance. However, when treating multiple blades simultaneously, large temperature differences often occur, making it challenging to ensure consistent and uniform temperatures. This paper establishes a numerical algorithm that links blade temperature with radiant energy, optimizing blade arrangement to achieve uniform energy distribution and temperature field homogenization. The improved view factor finite element algorithm is more suitable for blade structures. The Particle Swarm Optimization (PSO) and Coordinate Descent (CD) methods were used to solve the optimization function, aiming to minimize the temperature difference among blades. Finite element simulation was utilized to model the temperature field of the blades during radiative heat transfer from heating elements. The PSO and CD optimization methods were employed to find the local optimal solution that minimizes the view factor variance, reducing it from 2.24 before optimization to about 1. Simultaneously, the optimized maximum average temperature difference of the blades was 71.1 °C, approximately 50 % lower than the 138.8 °C before optimization. By comparing the view factor values with the simulated temperature fields, the strong correlation between the view factor and blade temperature was verified. This paper innovatively proposes a numerical method for optimizing blade arrangement to homogenize the temperature field, effectively enhancing temperature consistency during the heat treatment process.

In-situ synchrotron x-ray photoelectron spectroscopy study of medium-temperature baking of niobium for SRF application

In order to determine optimal parameters of vacuum thermal processing of superconducting radiofrequency niobium cavities exhaustive information on the initial chemical state of niobium and its modification upon a vacuum heat treatment is required. In the present work the chemical composition of the niobium surface upon ultra-high vacuum baking at 200 ∘C–400 ∘C similar to ‘medium-temperature baking’ and ‘furnace baking’ of cavities is explored in-situ by synchrotron x-ray photoelectron spectroscopy (XPS). Our findings imply that below the critical thickness of the Nb2O5 layer ( ≈1nm ) niobium starts to interact actively with surface impurities, such as carbon and phosphorus. By studying the kinetics of the native oxide reduction, the activation energy and the rate-constant relation have been determined and used for the calculation of the oxygen-concentration depth profiles. It has been established that the controlled diffusion of oxygen is realized at temperatures 200 ∘C–300 ∘C, and the native-oxide layer represents an oxygen source, while at 400 ∘C the pentoxide is completely reduced and the doping level is determined by an ambient oxygen partial pressure. Fluorine (F to Nb atomic ratio is 0.2) after the buffered chemical polishing was found to be incorporated into the surface layer probed by XPS ( ≈4.6nm ), and its concentration increased during the low-temperature baking (F/Nb = 0.35 at 230 ∘C) and depleted at higher temperatures (F/Nb = 0.11 at 400 ∘C). Thus, the influence of fluorine on the performance of mid-T baked, nitrogen-doped and particularly mild-baked (120 ∘C/48 h) cavities must be considered. The possible role of fluorine in the educed Nb+5→Nb+4 reaction under the impact of an x-ray beam at room temperature and during the thermal treatment is also discussed. The range of temperature and duration parameters of the thermal treatment at which the niobium surface would not be contaminated with impurities is determined.

P‐100: Control of Vacuum Pressure in Vacuum Drying Process for Uniform Film Formation of Inkjet‐Printed OLEDs

To enhance the performance of inkjet OLED/QLED devices, achieving a uniform film during the drying process is crucial. This study aims to improve both intra‐pixel and inter‐pixel uniformity in the drying process of inkjet printing technology. We conducted a comprehensive analysis of drying characteristics under various mixed solvent boiling points in nitrogen(N2) conditions. Additionally, during vacuum drying process, we carefully studied the characteristics based on adjustments in vacuum pressure and heating. Our focus was on analyzing the thickness profiles of dried pixel arrays in different positions: top, center, bottom, and left parts. Through the optimization of vacuum drying using solvents with a high boiling point (BP), we successfully achieved uniform film formation within and between pixels in inkjet‐printed pixel arrays.

The impact of Activation on the Performance of Optical Oxygen Sensing with the Luminescent Metal–Organic Framework MOF‐76(Eu)

AbstractThe influence of activation as key parameter for oxygen sensing by luminescent metal–organic frameworks has been investigated and quantified for the archetype MOF‐76(Eu). Activation at different conditions (regarding temperature and solvent‐exchange for distinct vacuum pressure and heating time), shows an influence on the overall quenching, response time and cyclability due to different pore accessibility and surface area and therefore on the overall performance of the sensor. The optical sensing process is based on luminescence quenching, analyzed from high vacuum (10−7 bar) to ambient pressure by dosing oxygen from 0.01 bar to 1 bar. Strong influence of the different activation parameters is observed, as MOF‐76(Eu) activated at 50 °C shows limited quenching of the luminescence intensity within 30 min, while methanol‐exchange and subsequent activation at 250 °C leads to a quenching rate of 98.6 %. In addition, the sensor response occurs more than 1000 times faster within 0.2 s. These results correlate well with physisorption data, which reveal a significant change in porosity and surface area according to the degree of activation. For a better understanding of the involved processes, adsorption isotherms were recorded, surface areas determined and correlated to the photophysical parameters, including Stern‐Volmer kinetics and cycling experiments for the differently activated MOF sensors.

Optical properties of lead-free Cs3Bi2I9 nanowire arrays prepared by template

Bismuth-based (Bi) perovskites have garnered significant interest as alternatives to lead-based (Pb) perovskites in photoelectric applications due to their non-toxicity and diverse structural properties. However, the inherent high limitation of electrons presents a significant challenge to their further utilization in various applications. Herein, all-inorganic Cs3Bi2I9 nanowire arrays have been successfully prepared by AAO template combined with the two-step method of low-temperature solution. Compared to the Cs3Bi2I9 film, the Cs3Bi2I9 nanowire arrays obtained the higher photoluminescence intensity, indicating a strong interaction between Cs3Bi2I9 and AAO, resulting from the significant weakening of the high electron confinement in the valence band of Cs3Bi2I9, which presenting as the valence band of the Cs3Bi2I9-AAO is mainly contributed by the O 2p orbital, while the conduction band does not change significantly. In addition, the Cs3Bi2I9 nanowire arrays have been demonstrated with the enhanced environmental and thermal stability, which maintain 90 % of their initial photoluminescence intensity after 120 h (in a vacuum) heating at 80 °C or after 10 days in the air (relative humidity of 40 %).

Mixed-batch scheduling to minimize total tardiness using deep reinforcement learning

This study addresses the issue of scheduling batch machine to minimize total tardiness. Vacuum heat treatment allows multiple jobs to be processed as a batch, as long as they do not exceed the machine's weight and size limits; the weight and size of the jobs both impact the batch processing time. By considering the differences in the release time and due date for each job, a mixed-integer linear programming model is developed and validated using small-scale instances. To tackle large-scale scheduling problems, an intelligent algorithm based on deep reinforcement learning is proposed. Double deep Q-learning networks are designed, and the environmental state feature matrix is extracted as input parameters for the networks. Four job-sorting rules and three scheduling time windows are defined, resulting in twelve action rules within the action space. The most suitable action rule is dynamically selected based on the current batch's environmental status during the scheduling process. Through extensive comparison using large-scale random data, the proposed algorithm demonstrates significantly improved scheduling performance compared to the benchmark algorithms.

Superior Catalytic Performance and Methanol Tolerance of Co@Mesoporous Graphene Nanocomposites toward Oxygen Reduction Reaction

AbstractThe global energy crisis and growing concerns about environmental pollution have spurred researchers to explore eco‐friendly methods of generating clean energy. Previous studies have often relied on noble metal catalysts to facilitate oxygen reduction reactions (ORR) in energy production reactions. However, their high cost has limited their widespread adoption, making the development of highly active and affordable ORR catalysts a significant challenge. In this study, a vacuum heat treatment technique was employed to fabricate a cobalt‐loaded mesoporous graphene (Co−Gs) nanocomposite. The inclusion of cobalt in graphene enhances the reaction, while the presence of mesoporous graphene provides a larger surface area to accommodate the active sites of Co. This synergistic effect promotes the improvement of catalytic performance. Additionally, the stability and methanol tolerance of Co−Gs nanocomposites is also superior than that of Pt−C. The excellent catalytic performance of the Co−Gs nanocomposite is attributed to a four‐electron pathway within the nanocomposite, as demonstrated by electrocatalytic kinetics investigations. Additionally, the interface interaction between the Co nanoparticles and Gs enhances the efficiency of electron transfer, effectively improving the catalytic performance. These findings highlight the potential of Co‐loaded graphene nanocomposites as highly efficient and cost‐effective electrocatalysts for clean energy application.

Structure and optical properties of aluminum oxide films (Al2O3) after heating in water vapor and vacuum

Structure and optical properties of aluminum oxide films (Al2O3) after heating in water vapor and vacuum

Investigation on a mobile fire extinguishing approach using liquid carbon dioxide as inert medium for underground mine.

Injecting carbon dioxide is the most effective means of preventing and extinguishing fires in sealing hazardous areas, but the traditional method slowly and remotely injects carbon dioxide gas into the well after gasification on the ground, which is dependent on the complete mine pipe network without cooling effect. To inject liquid directly from the tank with vacuum interlayer and heat insulating powder for rapid inerting and cooling, a new approach using track mobile platform to go deep into the underground mine disaster area is proposed, so the liquid can be delivered to the nozzle at the end of DN40 large diameter pipe, and the continuous gasification jet can be realized. The experimental results show that: (1) The liquid volume in a tank of vacuum degree within 2.0 Pa and 200 mm interlayer reduced no more than 15.5% after 48 days; (2) Taking the pressure in the tank as the power source, because of environmental differences inside and outside the pipe after 100 m pressure holding delivery, the physical form of liquid and gas could be converted instantly; (3) The continuous discharge time without ice blocking for a tank full of 2 m3 liquid was about 10.5 min under 25 L dual mode nitrogen pressurization, which is 1/12 of injection time after ground gasification; (4) Based on the temperature decrease trend measured at different positions, the cooling characteristics on liquid gasification jet path are quantified, and the calculation formula of temperature changing with time on the center line of liquid gasification jet is obtained. Through this new approach, the integration of vacuum insulated storage, safe mobile transportation, and continuous and rapid release with large flow can be achieved for the liquid carbon dioxide.

Three-dimensional deformation measurement techniques in space multi-physical fields based on digital image correlation

Aiming at the three-dimensional deformation measurement requirement of the high-stability structure of spacecraft in space multi-physical fields, a comprehensive instrument protection device in a vacuum high-low temperature environment is developed using ultra-low temperature anti-condensation and vacuum heat insulation technology. This ensures that the digital image correlation (DIC) measurement camera always remains in a constant temperature and pressure environment and can stably exert its original efficiency in space multi-physical field environments. Subsequently, a path-dependent DIC method based on a graphics processing unit computing parallel acceleration is proposed by combining a pre-interpolation strategy and integrated image technology, which realizes high-precision matching of digital images before and after deformation in a spatial multi-physical field environment and improves the computing efficiency. To address the problem that a common reference point may deform significantly in a space environment with a large temperature change, which leads to inaccurate system accuracy, combined with a random sampling consistency algorithm and singular value decomposition method, the optimal registration of the coordinate system and the solution of deformation were realized by setting the threshold of the reference point margin screening. Finally, a three-dimensional deformation measurement system in high- and low-temperature vacuum environments was built, and the three-dimensional deformation measurement of the satellite antenna in high- and low-temperature vacuum environments was verified, which proves the effectiveness and accuracy of the above method.

Understanding the effect of bondcoat surface treatment on enhanced lifetime of suspension plasma sprayed thermal barrier coatings

Thermal barrier coatings (TBCs) are extensively used in gas turbine engines in power generation and aerospace applications. Improvements in TBC performance and lifetime are continuously pursued by the gas turbine industry. Suspension plasma spraying (SPS) has shown promising results in recent years as it could produce a porous columnar TBC microstructure exhibiting low thermal conductivity and high durability. Further improvements in lifetime and fundamental understanding of failure mechanisms would lead to their wider application.Lifetime of a TBC system is dependent not only on the topcoat microstructure and chemistry, but also on topcoat-bondcoat interface and bondcoat characteristics as they influence the growth rate of thermally grown oxide (TGO) layer as well as the mismatch stresses generated in the topcoat during operation. Moreover, in SPS TBCs, the column density and porosity in the topcoat are also affected by the bondcoat surface roughness which in turn affects TBC lifetime. In previous work, it was shown that bondcoat surface treatment by shot peening followed by light grit blasting can significantly enhance the cyclic lifetime of SPS TBCs.The objective of this work was to gain further insight into the lifetime improvements due to surface treatment of bondcoat. Commercial NiCoCrAlY powder was deposited by high velocity air fuel (HVAF) and high velocity oxy fuel (HVOF) spraying while SPS was used to deposit yttria stabilised zirconia topcoat. Before spraying the topcoat, the bondcoat samples were subjected to vacuum heat treatment, shot peening, and/or grit blasting. Residual stress measurements were performed by X-ray diffraction on samples with different variants of bondcoat treatments and compared with Almen strip tests. The lifetime was examined by thermal cyclic fatigue testing. The relationships between changes in bondcoat surface roughness, residual stress state and microstructure due to surface treatments, and resultant topcoat microstructure and lifetime were studied and discussed.

Reducing two-level systems dissipations in 3D superconducting niobium resonators by atomic layer deposition and high temperature heat treatment

Superconducting qubits have arisen as a leading technology platform for quantum computing, which is on the verge of revolutionizing the world's calculation capacities. Nonetheless, the fabrication of computationally reliable qubit circuits requires increasing the quantum coherence lifetimes, which are predominantly limited by the dissipations of two-level system defects present in the thin superconducting film and the adjacent dielectric regions. In this paper, we demonstrate the reduction of two-level system losses in three-dimensional superconducting radio frequency niobium resonators by atomic layer deposition of a 10 nm aluminum oxide Al2O3 thin films, followed by a high vacuum heat treatment at 650 °C for few hours. By probing the effect of several heat treatments on Al2O3-coated niobium samples by x-ray photoelectron spectroscopy plus scanning and conventional high resolution transmission electron microscopy coupled with electron energy loss spectroscopy and energy dispersive spectroscopy, we witness a dissolution of niobium native oxides and the modification of the Al2O3-Nb interface, which correlates with the enhancement of the quality factor at low fields of two 1.3 GHz niobium cavities coated with 10 nm of Al2O3.

CO2 capture by modified clinoptilolite and its regeneration performance

This study focuses on CO2 capture by pressure swing adsorption (PSA), with modified clinoptilolite as the adsorbent. Natural clinoptilolite is modified by roasting, by acid pickling, by a combination of acid pickling and roasting, and by ion exchange. Modification by acid pickling–roasting and by ion exchange are found to give the highest CO2 adsorption capacities, of 730 mL/g and 876.7 mL/g, respectively. It is found that regeneration of clinoptilolite by a combination of vacuum desorption and heating enables recovery of as much as 89% of its previous CO2 adsorption capacity. To examine the CO2 adsorption capacity of clinoptilolite when applied to mixed gas, a simulated coking exhaust containing 12% CO2 and 4% O2 is used, and it is found that ion exchange modified clinoptilolite achieves a CO2 removal efficiency of 92.5%. A BET test reveals that acid pickling–roasting and Na+ modification enhance the porosity of clinoptilolite, thereby improving its adsorption capacity. This work demonstrates the feasibility of applying modified clinoptilolite as an effective adsorbent for CO2 capture, providing a promising tool for dealing with greenhouse gases.

Effect of dry heat and its combination with vacuum heat on physicochemical, rheological and release characteristics of Alocasia macrorrhizos retrograded starches

Retrograded starches have received increasing attention due to their potential excipient properties in pharmaceutical formulations. However, to evade its application-oriented challenges, modification of retrograded starch is required. The study emphasizes influence of dry heating and the dual heat treatment by dry heating amalgamation with the vacuum heat treatment on quality parameters of retrograded starch. The starch was isolated by using two different extraction media (0.05 % w/v NaOH and 0.03 % citric acid) from Alocasia macrorrhizos and then retrograded separately. Further, retrograded starches were first modified by dry heating and afterwards modified with combination of dry and vacuum heating. Modification decreased moisture, ash content and increased solubility. Modified Samples from NaOH media had higher water holding capacity and amylose content. X-ray diffraction revealed type A and B crystals with increasing crystallinity of retrograded heat-modified samples from NaOH media. Thermogravimetric analysis, differential scanning calorimetry confirmed thermal stability. Shear tests showed shear-thinning behavior whereas dominant storage modulus (G/) over loss modulus (G//), depicting gel-like behavior. Storage, loss, and complex viscosity initially increased, then decreased with temperature. In-vitro release reflects, modified retrograded starches offers versatile drug release profiles, from controlled to rapid. Tailoring starch properties enables precise drug delivery, enhancing pharmaceutical formulation flexibility and efficacy.

Highly efficient (V2O5)0.91Zn0.09 powdered catalyst for water organic pollutant elimination

(V2O5)1-x Znx powdered samples with different light doping levels (x = 0.03–0.09) were prepared by a solid-state thermal reaction and studied by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), energy dispersive analysis (EDAX), and optical diffuse reflectance spectroscopies. The prepared samples has been revealed that the increments in Zn-doping levels accompanied by vacuum heat treatment lead to the appearance of an additional V12O26 phase beside the pure V2O5 oxide, resulting not only in more donor vanadium atom liberation but also in multi-heterojunction component formation. Besides, Eg values decrease from 2.38 to 2.2 eV as Zn doping increases from x = 0 to x = 0.09. All previous observations improve the process of purifying water from pollutants by increasing the number of free carriers of V2O5 powder by adding Zn atoms and making vacuum heat treatments. The photocatalytic examination has been carried out using constants of 0.5 g and 0.01 g/L (10 ppm) of the catalyst quantity and MB-dye concentration, respectively, under Vis – irradiations. The acidic solution medium with a pH of 2 strongly motivated the degradation activity. The highest catalytic efficiency of 99.78% was attained by the (V2O5)0.91 Zn 0.09 compound within a time of 70 min and continued invariably for 5 hours in the dark. These catalytic results have proved the possibility of their reusability.