Search Results (67)

With increasing popularity of food delivery services, the microbial safety of transported meals should be ensured. An effect of the type of a meal (cooked rice; mashed potatoes; mushroom sauce), inner primary packaging (sugarcane bagasse [SB] tray; polypropylene [PP] tray), secondary container (polyester/polyethylene foam/aluminum foil [PPA] bag; PP box) on the time interval of the internal hot ready-to-eat (RTE) meal temperature decrease to the value critical for Bacillus cereus growth (40 °C) was tested during a simulated delivery; in aliquot samples of the same meals, B. cereus growth was quantified presuming a natural contamination of the meals. Type of a meal had no effect on the tested time interval (p > 0.05). Packaging a meal in the PP tray as compared to the SB tray and inserting primary trays into the PP box instead of PPA bag delayed (p < 0.05) the internal meal temperature decrease by 50 and 15 min, respectively. Average B. cereus counts in the naturally contaminated meals after the four-hour culturing at 40 °C was 2.99 log CFU·g⁻¹. It was concluded that a hot RTE meal delivered up to four hours under the tested conditions is not likely to facilitate B. cereus growth above unacceptable levels. Full article

Based on the engineering background of a new type of segmental-assembled steel temporary beam buttress, the fatigue strength evaluation method of the steel box girders with open longitudinal ribs was taken as the research objective. The fatigue stress calculation analysis and the full-scale fatigue loading test for the steel box girder local component were carried out. The accuracy of the finite-element model was verified by comparing it with the test results, and the rationality of the fatigue strength evaluation methods for welded joints was deeply explored. The results indicate that the maximum nominal stress occurs at the weld toe between the transverse diaphragm and the top plate at the edge of the loading area, which is the fatigue-vulnerable location for the steel box girder local components. The initial static-load stresses at each measuring point were in good agreement with the finite-element calculation results. However, the static-load stress at the measuring point in the fatigue-vulnerable position shows a certain decrease with the increase in the number of cyclic loads, while the stress at other measuring points remains basically unchanged. According to the finite-element model, the fatigue strengths obtained by the nominal stress method and the hot-spot stress method are 72.1 MPa and 93.8 MPa, respectively. It is reasonable to use the nominal stress S-N curve with a fatigue life of 2 million cycles at 70 MPa and the hot-spot stress S-N curve with a fatigue life of 2 million cycles at 90 MPa (FAT90) to evaluate the fatigue of the welded joints in steel box girders with open longitudinal ribs. According to the equivalent structural stress method, the fatigue strength corresponding to 2 million cycles is 94.1 MPa, which is slightly lower than the result corresponding to the main S-N curve but within the range of the standard deviation curve. The research results of this article can provide important guidance for the anti-fatigue design of welded joints in steel box girders with open longitudinal ribs. Full article

A novel approach to the quantum version of $\kappa$-entropy that incorporates it into the conceptual, mathematical and operational framework of quantum computation is put forward. Various alternative expressions stemming from its definition emphasizing computational and algorithmic aspects are worked out: First, for the case of canonical Gibbs states, it is shown that $\kappa$-entropy is cast in the form of an expectation value for an observable that is determined. Also, an operational method named “the two-temperatures protocol” is introduced that provides a way to obtain the $\kappa$-entropy in terms of the partition functions of two auxiliary Gibbs states with temperatures $\kappa$-shifted above, the hot-system, and $\kappa$-shifted below, the cold-system, with respect to the original system temperature. That protocol provides physical procedures for evaluating entropy for any $\kappa$. Second, two novel additional ways of expressing the $\kappa$-entropy are further introduced. One determined by a non-negativity definite quantum channel, with Kraus-like operator sum representation and its extension to a unitary dilation via a qubit ancilla. Another given as a simulation of the $\kappa$-entropy via the quantum circuit of a generalized version of the Hadamard test. Third, a simple inter-relation of the von Neumann entropy and the quantum $\kappa$-entropy is worked out and a bound of their difference is evaluated and interpreted. Also the effect on the $\kappa$-entropy of quantum noise, implemented as a random unitary quantum channel acting in the system’s density matrix, is addressed and a bound on the entropy, depending on the spectral properties of the noisy channel and the system’s density matrix, is evaluated. The results obtained amount to a quantum computational tool-box for the $\kappa$-entropy that enhances its applicability in practical problems. Full article

In this study, a new compact “hot-box” prototype with a volume of 0.602 m³ has been designed, instrumented, and implemented to experimentally characterize the thermal conductivity of specimens measuring 25 cm × 25 cm, with the thickness of the specimen varying up to a maximum of 10 cm. The prototype features a novel design aimed at enhancing flexibility and speed in changing specimens, thereby reducing downtime when testing different materials. It requires minimal space and incurs low development and maintenance costs. To validate the prototype’s functionality for measuring thermal conductivity, an oak wood specimen with a thickness of 3.81 cm was experimentally tested. The results indicate that the control system maintains key parameters under steady-state conditions for a significant duration. The thermal conductivity obtained for the oak wood specimen is 0.1695 W/m·K, with an expanded uncertainty of 0.0183 W/m·K for a 95% confidence interval. Full article

Background/Objectives: Carvacrol, a monoterpenoid phenol found in essential oils, exhibits many biological activities, including anticancer properties through mechanisms such as induction of apoptosis. These properties can be enhanced if encapsulated within nanoparticles. This study focuses on producing functionalized carvacrol-loaded nanostructured lipid carriers (NLCs) applied to the treatment of breast cancer. Methods: NLCs were produced by hot emulsification with the sonication method and optimized by the Box–Behnken design, considering Precirol^® (1, 4, 7%), carvacrol (1, 5, 9%), and Tween^® (0.1, 0.5, 0.9%) as independent variables. Results: The optimized NLC containing 2% carvacrol had a particle size of 111 ± 2 nm, PdI of 0.26 ± 0.01, and zeta potential of −24 ± 0.8 mV. The solid lipid (Precirol^®) was the variable that most influenced particle size. NLCs were functionalized with Pluronic^® F68, cholesterol, chitosan, and polyethylene glycol (0.05–0.2%), with oNLC-Chol presenting the most promising results, with no significant increase in particle size (±12 nm) and high encapsulation efficiency (98%). Infrared spectra confirm effective carvacrol encapsulation, and stability tests showed no significant physicochemical changes for 120 days of storage at 4 °C. When incubated with albumin (5 mg/mL), NLCs showed overall good stability over 24 h, except for oNLC-Chol, which increased slightly in size after 24 h. In addition, oNLC increased the cytotoxic effect of carvacrol by 12-fold, resulting in an IC₅₀ of 7 ± 1 μg/mL. Conclusions: Therefore, it was possible to produce stable, homogeneous NLCs with nanometric sizes containing 2% carvacrol that displayed improved anticancer efficacy, indicating their potential as a delivery system. Full article

The traditional timber architecture of Qiandongnan represents a rich cultural heritage. However, urbanization has led to the replacement of these structures with concrete and brick buildings, resulting in the loss of both functionality and cultural identity. To bridge the gap between traditional architecture and modern building needs, this study conducted field surveys to extract key design parameters from local structures, enabling the development of a modular framework for Structural Insulated Panels (SIPs) based on the dimensions of traditional dwellings. Four types of SIPs were developed using Chinese fir, OSB, EPS, and XPS, and their thermal performance and heat stability were evaluated through theoretical analysis and hot box testing. The results show that all specimens met the required heat transfer coefficient. The combination of OSB and XPS showed a slightly lower heat transfer coefficient of 0.60 compared to Chinese fir, which had a coefficient of 0.62. However, the Chinese fir–XPS combination provided the longest time lag of 6.34 h, indicating superior thermal stability. Due to the widespread use of Chinese fir in local construction and its compatibility with the landscape, this combination is ideal for both energy efficiency and cultural preservation. Full article

This paper concerns measurements and CFD simulations of vacuum-insulated glazing (VIG), which consists of two glass panes separated by a narrow gap from which air has been removed. Distancers, e.g., in the form of small balls, are inserted into this gap every few centimeters to prevent the glass from deflecting. In the first part, simulations of two-pane VIG thermal transmittance with the Ansys Fluent program are described, resulting in thermal transmittance of VIG without the network of distancers equal to 2.18 W/(m²K) and with the distancers equal to 2.29 W/(m²K). The influence of the supports on the thermal transmittance of VIG is also determined. The CFD results show that the supporting balls increase the two-pane VIG thermal transmittance by about 0.15% with respect to the glazing without the distancers. Then, VIG is analyzed both numerically and tested in two measurement stands. Firstly, the tests are performed in a guarded hot-plate apparatus, according to the EN ISO 8302 standard. The two-pane glazing with one low-emissivity coating has a measured thermal transmittance equal to 1.75 W/(m²K). Other measurements were undertaken in the calorimetric chamber equipped with the hot-box apparatus. The results of the numerical assessment are then compared to the measurements of the existing three-pane vacuum-insulated glazing with two low-emissivity coatings, the same as simulated. The procedure follows the EN ISO 8990 standard. Measurement results of 1.10 W/(m²K) are compared to the simulation results of VIG thermal transmittance equal to 1.09 W/(m²K). A satisfactory agreement is reached. Additionally, this paper considers a new correction coefficient to thermal transmittance according to standard EN 673 in order to achieve a proper calculation of vacuum-insulated glazing in the center-of-glass region. The authors propose to use an adjustment coefficient of 1.05 when calculating the thermal transmittance of vacuum-insulated glazing without taking into account convection in the vacuum space and the thermal influence of distancers. Full article

This study explores the valorization of non-commercial chestnut waste from the Portuguese chestnut industry to develop biocomposites. The composites were obtained by hot compression molding, and a Box–Behnken Design model was employed to optimize the mechanical, thermal, and water resistance properties of the chestnut-based composite, using fruit and shell fibers, respectively, as the polymeric matrix and reinforcement agent. The optimal formulation, comprising 70% chestnut, no glycerol, a molding temperature of 120 °C, and applying a pressure of 2.93 MPa for 30 min, achieved a Flexural Strength of 9.00 MPa and a Flexural Modulus of 950 MPa. To enhance water resistance, shellac was added as a natural hydrophobic coating. Water interaction tests indicated that shellac-treated biocomposites exhibited superior water resistance, absorbing approximately two times less water than those containing glycerol or untreated samples. Thermal analysis revealed that glycerol acted as a plasticizer, improving flexibility and reducing the glass transition temperature. Additionally, the chestnut-based biocomposite demonstrated an out-of-plane thermal conductivity of 0.79 W/m·K, categorizing it as a thermal insulator. The final prototype application was a candle holder, showcasing the potential for the practical and sustainable use of chestnut-based composite. This research highlights the potential for chestnut waste to be repurposed into eco-friendly products, offering an alternative to conventional plastics and contributing to a circular economy. Full article

The accurate thermal performance assessment of building components is critical for improving energy efficiency in buildings, mainly as space climatization accounts for a large percentage of energy consumption. The literature review points out multiple parameters that influence the measurement of the U-value using the HFM method. However, most of these studies are focused on in situ tests and little information exists on the variability of the results of the hot box method to assess thermal resistance. According to EN 1934, a baffle must be positioned between the surface of the specimen and the fans of the climatic chamber to maintain acceptable air temperature gradients and uniform air temperature distribution to minimize the convective effects. However, no clear information about its position is given. This study investigates the variability in the measurement of the thermal resistance of double leaf brick wall specimen using the hot box method, focusing on the effect of the layout configuration. An experimental campaign was carried out and three configurations were considered: no baffle, a baffle positioned 1.15 m from the wall, and a baffle positioned 0.05 m from the specimen. The experimental results demonstrate that baffle positioning significantly influences measurement variability. The best-performing configuration (P1) resulted in the lowest variability and the closest agreement with theoretical values, with an average R-value deviation of approximately 25%. These findings are relevant for optimizing testing protocols and improving the reliability of thermal resistance assessments. Furthermore, the results have implications for energy efficiency policies and building retrofitting strategies, aligning with global sustainability goals to reduce building energy demand and carbon emissions. Full article

Buildings consume significant energy, much of which is used for heating and cooling. Insulation reduces undesired heat transfer to save on heating and cooling energy usage. Radiant barriers are a type of insulation technology that reduces radiant heat absorbed by a structure. Applying radiant barriers to buildings reduces costs and improves both energy efficiency and occupant comfort. However, homes often have favorable thermal gradients that could also be used to reduce energy usage if the insulation properties were switched dynamically. This article introduces two dynamic radiant barriers intended for residential attics, which can switch between reflecting and transmitting states as needed. These radiant barriers are manufactured as a single deformable assembly using sheet materials and are compatible with various actuation mechanisms. The efficacy of these radiant barriers is reported based on a hotbox experiment and numerical calculations. The experimental results demonstrate that both proposed dynamic radiant barrier designs increase effective thermal resistance by factors of approximately 2 when comparing insulating to conducting states, and by approximately 4 when comparing the insulating state to the case without a radiant barrier. Additionally, the dynamic radiant barriers achieve heat flux reductions up to 41.9% in the insulating state compared to tests without a dynamic radiant barrier. Full article

Utilizing phase change materials (PCMs) in passive energy-saving wall panels to regulate indoor temperatures during hot seasons can improve people’s thermal comfort and reduce the energy consumption of air conditioning systems. This study is based on the hot summer and warm winter climatic characteristics of Hainan. According to local meteorological data and residents’ living habits, a suitable phase change temperature of approximately 28 °C was determined. A composite PCM of paraffin and stearic acid n-butyl ester was prepared and tested for thermal performance. Encased in an aluminum box with non-penetrating aluminum rods to enhance heat transfer, the phase change panel was applied to the inner side of exterior walls. Thermal tests demonstrated that increasing the mass ratio of stearic acid n-butyl ester to paraffin lowers the melting point and latent heat. At a 3:7 mass ratio, the melting point of the composite PCM was 28.30 °C, and the latent heat was 128.26 J/g. The 20 mm thick panel maintained a stable phase change process, with unheated surface temperatures between 28 °C and 29 °C for up to 180 min. Compared to panels without aluminum rods, those with rods exhibited a 20% longer phase change time, extended heat transfer paths, and reduced liquid-phase convective heat transfer rates, demonstrating improved PCM utilization. Therefore, the phase change panel with non-penetrating aluminum rods exhibits excellent insulation and temperature control properties. Full article

This study explored the combined administration of docetaxel (DOC) and erlotinib (ERL) using nanostructured lipid carriers (NLCs), with folic acid (FA) conjugation to enhance their synergistic anticancer efficacy against triple-negative breast cancer. NLCs were developed through hot melt homogenization–ultrasound dispersion, and optimized by a quality-by-design (QbD) approach using Plackett–Burman design and Box–Behnken design. Plots were generated based on maximum desirability. Spherical, nanosized dispersions (<200 nm) with zeta potential ranging from −16.4 to −14.15 mV were observed. These nanoformulations demonstrated ~95% entrapment efficiency with around 5% drug loading. Stability tests revealed that the NLCs remained stable for 6 months under storage conditions at 4 °C. In vitro release studies indicated sustained release over 24 h, following Higuchi and Korsmeyer–Peppas models for NLCs and FA NLCs, respectively. Additionally, an in vitro pH-stat lipolysis model exhibited a nearly fivefold increase in bioaccessibility compared to drug-loaded suspensions. The DOC–ERL-loaded formulations exhibited dose- and time-dependent cytotoxicity, revealing synergism at a 1:3 molar ratio in MDA-MB-231 and 4T1 cells, with combination indices of 0.35 and 0.37, respectively. Co-treatment with DOC–ERL-loaded FA NLCs demonstrated synergistic anticancer effects in various in vitro assays. Full article

To further improve the manufacturing process and product performance of decorated bamboo filament board, the Box–Behnken response surface analysis method was used to analyze the correlation between the hot-pressing parameters and surface bonding strength, and the optimal process optimization parameters were obtained. In addition, the wettability and color of each group of samples were tested. The results show that the optimum process parameters of decorated bamboo filament boards were 130 °C, 165 s and 2.00 MPa, and the surface bonding strength was 1.58 MPa. The relative error between the measured value and the predicted value was less than 5%. The contact angle of the bamboo filament after hot pressing was higher than without hot pressing. However, there was no correlation between wettability and the hot-pressing parameters. There was no effect on the change in bamboo surface color. This indicates that the temperature range selected in this study meets the requirements of surface color control in production. Full article

Through the study of the thermal rheological behavior of Ti6Al4V alloy at different temperatures (500 °C, 600 °C, 700 °C, and 800 °C) and different strain rates (0.1 s⁻¹, 0.05 s⁻¹, 0.01 s⁻¹, and 0.005 s⁻¹), a constitutive model was developed for Ti6Al4V alloy across a wide temperature range in the hot stamping process. The model’s correlation coefficient reached 0.9847, indicating its high predictive accuracy. Hot processing maps suitable for the hot stamping process of Ti6Al4V alloy were developed, demonstrating the significant impact of the strain rate on the hot formability of Ti6Al4V alloy. At higher strain rates (>0.05 s⁻¹), the hot processing of Ti6Al4V alloy is less prone to instability. Combining hot processing maps with hot stamping experiments, it was found that the forming quality and thickness uniformity of parts improved significantly with the increase in stamping speed. The phase composition and microstructures of the forming parts under different heating temperature conditions have been investigated using SEM, EBSD, XRD, and TEM, and the maximum heating temperature of hot stamping forming was determined to be 875 °C. The recrystallization mechanism in hot stamping of Ti6Al4V alloys was proposed based on EBSD tests on different sections of a hot stamping formed box-shaped component. With increasing deformation, the effect of dynamic recrystallization (DRX) was enhanced. When the thinning rate reached 15%, DRX surpassed dynamic recovery (DRV) as the dominant softening mechanism. DRX grains at different thinning rates were formed through both discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX), with CDRX always being the dominant mechanism. Full article

The use of thermoplastic composites (TPCs) as one of the lightweight solutions will inevitably encounter problems in connection. Resistance welding has the characteristics of high strength, simplicity, and high reliability, and is considered a very potential hot-melt connection technology. The resistance welding technology of unidirectional carbon fiber-reinforced polyphenylene sulfide composites (UCF/PPS) was systematically studied. The experimental results show that the 100-mesh brass mesh has the best resin wetting effect and heating efficiency, and the PPS/oxidized 100-mesh brass mesh composite resistance element (Ox-RE/PPS) has the highest welding strength. The welding failure mode changes from interface failure and RE failure to interlayer structure damage and fiber fracture. The single-factor experimental results show that the maximum welding strength is reached at 310 °C, 1.15 MPa, and 120 kW/m². According to the conclusion of the single-factor experiment, the Box–Behnken method was further used to design a three-factor, three-level experiment, and a quadratic regression model was established according to the test results. The results of variance analysis, fitting curve analysis, and perturbation plot analysis proved that the model had high fitting and prediction abilities. From the 3D surface diagram analysis, the influence of power density is the largest, and the interaction between welding temperature and power density is the most significant. Combined with the analysis of Design Expert 13 software, the optimal range of process parameters was obtained as follows: welding temperature 313–314 °C, welding pressure 1.04–1.2 MPa, and power density 124–128 kW/m². The average strength of resistance welding joints prepared in the optimal range of process parameters was 13.58 MPa. Full article