Preparation and light-to-heat conversion efficiency of paraffin/graphene aerogel shape-stable phase change materials

A kind of shape-stable phase change materials (SSPCMs) was prepared by using graphene aerogel (GA) with different pore size adsorbing molten paraffin wax via vacuum impregnation. The characteristics of SSPCMs were determined by scanning electron microscopy (SEM), X-ray diffractometer (XRD), differential scanning calorimetry (DSC) and TCi thermal conductivity analyzer. The SSPCMs possessed a high comprehensive performance: a high thermal conductivity of 1.432?W/m·K (more than 400% increase over pure paraffin), a good capacity of thermal energy storage (more than 200?J/g), a ability to light-to-heat energy storage and coating effect (encapsulation ratio is about 55%) due to the three-dimensional GA foam structure with functions of thermal conductivity and adsorptive property. In addition, an energy conversion from light to heat was realized with the SSPCMs. For different morphologies of GA, as pore size of GA decreases, SSPCMs’ thermal conductivity and solar energy usage efficiency increases and their leakage rate reduces. This means that pore size of GA can influence the properties of SSPCMs to some extent.     

Boosting Alkaline Hydrogen and Oxygen Evolution Kinetic Process of Tungsten Disulfide-Based Heterostructures by Multi-Site Engineering

Alkaline water electrolysis is an advanced technology for scalable H₂ production using surplus electricity from intermittent energy sources, but it remains challenging for non-noble electrocatalysts to split water into hydrogen and oxygen efficiently, especially for tungsten disulfide (WS₂)-based catalysts. Density functional theory calculations in combination with experimental study are used to establish a multi-site engineering strategy for developing robust WS₂-based hybrid electrocatalyst on mesoporous bimetallic nitride (Ni₃FeN) nanoarrays for bifunctional water splitting. This ingenious design endows the catalyst with numerous edge sites chemically bonded with the conductive scaffold, which are favorable for water dissociation and hydrogen adsorption. Benefiting from the synergistic advantages, the N-WS₂/Ni₃FeN hybrid exhibits exceptional bifunctional properties for hydrogen and oxygen evolution reactions (HER and OER) in base with excellent large-current durability, requiring 84 mV to afford 10 mA cm^?2 for HER, and 240 mV at 100 mA cm^?2 for OER, respectively. Assembling the catalytic materials as both the anode and cathode to construct an electrolyzer, it is actualized very good activities for overall water splitting with only 1.5 V to deliver 10 mA cm^?2, outperforming the IrO₂⁽⁺⁾//Pt^(?) coupled electrodes and many non-noble bifunctional electrocatalysts thus far. This work provides a promising avenue for designing WS₂-based heterogeneous electrocatalysts for water electrolysis.     

银型抗菌白炭黑的改性研究

通过添加表面活性剂和有机溶剂对银型抗菌白炭黑进行改性研究。运用ICP、粒度分布仪对改性后银型抗菌白炭黑中抗菌离子含量、粒度分布进行表征;利用菌落计数法对改性后材料的抗菌性能进行研究;并与未改性的银型抗菌白炭黑进行比较。结果表明,改性后的银型抗菌白炭黑中抗菌离子含量高于未改性前;结构较改性前松散,且分散性好;粒径主要分布在3~6μm且均一;具有较好的热稳定性和光稳定性。     

Physicochemical characterization,identification and improved photo-stability of alpha-lipoic acid-loaded nanostructured lipid carrier

Objective: The ultimate goal of this research is to corroborate the physicochemical characterization of nanostructured lipid carrier (NLC) loading unstable lipophilic active ingredients with an antioxidant function, such as alpha-lipoic acid (ALA), and monitoring its photochemical stability of ALA-NLC against natural daylight. NLC is an innovative active compound delivery system in pharmaceutical and cosmetic fields. It has been recommended as active substance carriers to enhance the effectiveness of lipophilic compounds.

Methods: ALA-NLC was manufactured using hot high pressure homogenization technique to increase the water solubility and photo-stability. The physicochemical characterization properties of ALA-NLC have been determined in terms of nanoparticle size, zeta potential, polydispersity index value and size distribution. Size analysis was implemented through photon correlation spectroscopy and laser diffractometry. Morphological profile of nanoparticles was observed via atomic force microscopy. The loading of NLC containing ALA was evaluated by high performance liquid chromatography. ALA-NLC was subjected to UV-Vis spectrophotometer to validate the existence of ALA. Water contact angle measurement was manipulated to determine the hydrophilicity of the sample. The photo-stability of ALA-NLC within 120 days was assessed by the retention of ALA.

Results: The ALA-NLC provided maximum ALA retention of 93.9% in 30 days exposure to natural daylight, the retention of free ALA only 42.5%. About 88.5% of the initial ALA in NLC system remained after 120 days under the same conditions, while the retention of free ALA only 0.7% under natural daylight irradiation. The photo-stability of ALA was considerably enhanced by NLC formulation compared with free ALA itself. Therefore, the NLC formulation provided a reliable protection of ALA against natural daylight, enhancing its photochemical stability.

Conclusion: The present investigation elucidated that the NLC drastically improved the water solubility, particularly the facilitation of photo-stability of ALA exposure to natural daylight.     

How to carry out assembly line–cell conversion? A discussion based on factor analysis of system performance improvements

The line–cell (or line–seru) conversion is an innovation of assembly systems that has received less attention. Its essence is dismantling an assembly conveyor line and adopting a mini-assembly unit, called seru (or cell). In this paper, we discuss how to do such line–cell conversions, especially focusing on assembly cell formation (ACF) and assembly cell loading (ACL). We perform 64 arrays of full factorial experiment analysis that incorporate three factors: work stations, product types, and product lot sizes. We construct a two-objective line–cell conversion model that minimises the total throughput time (TTPT) and the total labour hours (TLH). Three non-dominated solutions obtained from the two-objective model are used to evaluate the performance of the line–cell conversion. By investigating the experimental results of the ACF and the ACL, we summarise several managerial insights that could be used to help successful line–cell conversions.     

Modeling of the emission rates of methyl ethyl ketone and effects of additives on the emission rate

Abstract

VOC(Volatile organic compound) emission rate was modelled in this study. The effects of the different environmental factors and the additives upon the emission rates were also determined. The study was conducted in a test chamber and in the field for determination of the emission rate of methyl ethyl ketone (MEK). Additionally, the theory of mass transfer was used to derive an MEK emission model with three variables (temperature, humidity, ventilation rate) and five coefficients (T ₁, R ₁, K_B , ACH_std and C_std ); these were determined by the results of emission rate in a test chamber. The emission rate of MEK ranged from 16.1 × 10³ to 101.0 × 10³ mg/m²/hr/(g‐MEK) for those cases which used solvents and plasticizer, and from 5.6×10³ to 58.1×10³ mg/m²/hr/(g‐MEK) when PVC powder was added. Additionally, the MEK emission rates increased with an increase in temperature, humidity, and ventilation rate. The mass transfer coefficients of MEK determined from the VOC emission model were approximately 0.00246 m/sec for those cases which used solvents and plasticizer, and decreased by a factor of 0.67 to 0.00164 m/sec for those cases which used solvents, plasticizer and PVC powder.     

Self-assembled core-shell polydopamine@MXene with synergistic solar absorption capability for highly efficient solar-to-vapor generation

As a renewable and environment-friendly technology for seawater desalination and wastewater purification, solar energy triggered steam generation is attractive to address the long-standing global water scarcity issues. However, practical utilization of solar energy for steam generation is severely restricted by the complex synthesis, low energy conversion efficiency, insufficient solar spectrum absorption and water extraction capability of state-of-the-art technologies. Here, for the first time, we report a facile strategy to realize hydrogen bond induced self-assembly of a polydopamine (PDA)@MXene microsphere photothermal layer for synergistically achieving wide-spectrum and highly efficient solar absorption capability (≈ 96% in a wide solar spectrum range of 250–1,500 nm wavelength). Moreover, such a system renders fast water transport and vapor escaping due to the intrinsically hydrophilic nature of both MXene and PDA, as well as the interspacing between core-shell microspheres. The solar-to-vapor conversion efficiencies under the solar illumination of 1 sun and 4 sun are as high as 85.2% and 93.6%, respectively. Besides, the PDA@MXene photothermal layer renders the system durable mechanical properties, allowing producing clean water from seawater with the salt rejection rate beyond 99%. Furthermore, stable light absorption performance can be achieved and well maintained due to the formation of ternary TiO2/C/MXene complex caused by oxidative degradation of MXene. Therefore, this work proposes an attractive MXene-assisted strategy for fabricating high performance photothermal composites for advanced solar-driven seawater desalination applications.

     

Automatic Detection of Aortic Dissection Based on Morphology and Deep Learning

Aortic dissection (AD) is a kind of acute and rapidly progressing cardiovascular disease. In this work, we build a CTA image library with 88 CT cases, 43 cases of aortic dissection and 45 cases of health. An aortic dissection detection method based on CTA images is proposed. ROI is extracted based on binarization and morphology opening operation. The deep learning networks (InceptionV3, ResNet50, and DenseNet) are applied after the preprocessing of the datasets. Recall, F1-score, Matthews correlation coefficient (MCC) and other performance indexes are investigated. It is shown that the deep learning methods have much better performance than the traditional method. And among those deep learning methods, DenseNet121 can exceed other networks such as ResNet50 and InceptionV3.     

Biradical-Featured Stable Organic-Small-Molecule Photothermal Materials for Highly Efficient Solar-Driven Water Evaporation

With recent progress in photothermal materials, organic small molecules featured with flexibility, diverse structures, and tunable properties exhibit unique advantages but have been rarely applied in solar-driven water evaporation owing to limited sunlight absorption resulting in low solar–thermal conversion. Herein, a stable croconium derivative, named CR-TPE-T, is designed to exhibit the unique biradical property and strong π–π stacking in the solid state, which facilitate not only a broad absorption spectrum from 300 to 1600 nm for effective sunlight harvesting, but also highly efficient photothermal conversion by boosting nonradiative decay. The photothermal efficiency is evaluated to be 72.7% under 808 nm laser irradiation. Based on this, an interfacial-heating evaporation system based on CR-TPE-T is established successfully, using which a high solar-energy-to-vapor efficiency of 87.2% and water evaporation rate of 1.272 kg m⁻² h⁻¹ under 1 sun irradiation are obtained, thus making an important step toward the application of organic-small-molecule photothermal materials in solar energy utilization.