Antibacterial hemostatic dressings with nanoporous bioglass containing silver

Nanoporous bioglass containing silver (n-BGS) was fabricated using the sol-gel method, with cetyltrimethyl ammonium bromide as template. The results showed that n-BGS with nanoporous structure had a surface area of 467 m2/g and a pore size of around 6 nm, and exhibited a significantly higher water absorption rate compared with BGS without nanopores. The n-BGS containing small amounts of silver (Ag) had a slight effect on its surface area. The n-BGS containing 0.02 wt% Ag, without cytotoxicity, had a good antibacterial effect on Escherichia coli, and its antibacterial rate reached 99% in 12 hours. The n-BGS’s clotting ability significantly decreased prothrombin time (PT) and activated partial thromboplastin time (APTT), indicating n-BGS with a higher surface area could significantly promote blood clotting (by decreasing clotting time) compared with BGS without nanopores. Effective hemostasis was achieved in skin injury models, and bleeding time was reduced. It is suggested that n-BGS could be a good dressing, with antibacterial and hemostatic properties, which might shorten wound bleeding time and control hemorrhage

Using fuzzy clustering and weighted cumulative probability distribution techniques for optimal design of phase change material thermal energy storage

This paper presents the development and application of a bi-objective optimisation strategy to optimise the design of thermal energy storage (TES) systems using phase change materials (PCMs). The overall objective is to maximise the average heat transfer effectiveness of the PCM TES system, while minimising the effective PCM charging time. The proposed strategy featured with the utilisation of a fuzzy clustering algorithm and a weighted cumulative probability distribution (FC-WCPD) technique to identify optimal designs of the PCM TES systems. The fuzzy clustering algorithm was first time introduced in a bi-objective optimisation algorithm and was used to evaluate and select the potential optimal solutions in each generation by taking into account the trade-off between the two conflicting optimisation objectives. The weighted cumulative probability distribution technique was used to transfer the optimal characteristics through iterations and facilitate the convergence of the optimisation process. The optimal design identified for the case studied was the inlet air temperature of 42 °C, the air flow rate of 74.91 l/s, the number of the PCM bricks in the air flow direction of 5, and the number of air channels of 4 when the weight factors were 0.5 for both optimisation objectives. By using this optimal design, the average heat transfer effectiveness of the PCM TES system and the effective PCM charging time were 61.87% and 6.61 h, respectively. Further comparison showed that the optimal design was consistent with the optimal solutions identified using a controlled elitist non-dominated sorting genetic algorithm (NSGA) and a multi-criteria decision-making (MCDM) process

Thermal performance investigation and optimization of buildings with integrated phase change materials and solar photovoltaic thermal collectors

This paper presents the thermal performance investigation and optimization of buildings with integrated phase change materials (PCMs) and solar photovoltaic thermal (PVT) collectors. PCMs are embedded into building envelopes to increase local thermal mass while PVT collectors are used to generate both electricity and low grade thermal energy for winter space heating. The thermal performance of a typical Australian house with PVT collectors and three different types of PCMs is simulated and analyzed by comparing with that of the house using PVT collectors only, using PCMs only, and without using PVT collectors and PCMs. The results showed that using PVT collectors and PCMs simultaneously can substantially improve the indoor thermal performance of the house. The Coefficients of Thermal Performance Enhancement (CTPE) of the house using PVT collectors and PCMs of RT18HC, SP21E and SP24E with a thickness of 20 mm were improved to 43.4, 48.8 and 46.2% respectively, compared to that of the house using the PCMs only (-9.1, 2.6 and 0.2% for RT18HC, SP21E and SP24E, respectively). The CTPE of the house can be increased to 70.2% if Taguchi method is used to determine the optimal air flow rate of PVT collectors, thickness of PCM layers, PCM type and additional wall insulation. The optimization results also showed that the additional wall insulation of the house was a critical factor affecting the thermal performance of the PCM enhanced buildings with PVT collectors

Preparation, thermal characterization and examination of phase change materials (PCMs) enhanced by carbon-based nanoparticles for solar thermal energy storage

This paper presents the preparation and thermal characterization of phase change materials (PCMs) enhanced by carbon-based nanoparticles, including graphene nanoplatelets (GNPs), multi-walled carbon nanotubes (MWCNTs) and nano-graphite (NG). A systematic experimental framework, consisting of material selection and preparation, material property characterization and thermal performance examination, was proposed and used in this study to facilitate the development of nano-enhanced PCMs (NePCMs) for solar thermal energy storage applications. By applying this framework, the characteristics and potential performance of PCM composites can be comprehensively understood, and better assessed before practical applications. It was found that the thermal conductivity of the myristic acid (MA) can be significantly enhanced by adding the nanoparticles in particular GNPs as additives into the PCM. The thermal conductivity of the PCM composites can be improved by 176.26%, 47.30% and 44.01% respectively under the solid phase, by adding GNPs, MWCNTs and NG with a concentration of 3 wt%. However, the concentration of the nanoparticles needs to be carefully determined to maximise the benefit in thermal conductivity enhancement. Different from that under the solid phase, the thermal conductivity enhancement of the NePCMs developed under the liquid phase followed linear increasing trends with relatively low increasing rates, when increasing the concentration of the nanoparticles. Besides the thermal conductivity enhancement, the adding of nanoparticles also modified the phase change process with a smaller phase change temperature range and eliminated supercooling while maintaining the high latent heat capacity. A further thermal performance examination demonstrated that the prepared NePCMs showed high thermal and chemical stability, which can be used to substantially reduce the phase transition time, and therefore are good potential candidates for solar thermal energy storage applications

Analysis of Surface Deformation Induced by Backfill Mining Considering the Compression Behavior of Gangue Backfill Materials

Coal gangue, as a solid waste produced in the coal mining process, can be disposed by being prepared into backfill materials and then filled in underground goafs, thus controlling strata movement and surface subsidence. However, gangue backfill materials are non-continuous; therefore, research into the surface deformation induced by backfill mining should consider the creep compression behavior of gangue backfill materials. The research took a backfill panel in Tangshan Coal Mine (Tangshan City, Hebei Province, China) as the background. In addition, broken coal gangue was collected in the field to prepare specimens of gangue backfill materials, and their creep compression properties were measured. The corresponding constitutive equation of creep compression was then established and embedded in the numerical software, FLAC3D. By building the numerical model for surface deformation induced by backfill mining, the surface deformation above the backfill panel under conditions of different creep durations of backfill materials was simulated and evaluated. In addition, two measuring lines were arranged on the surface to monitor changes in surface subsidence. After surface subsidence stabilized, the maximum surface subsidence was 163.4 mm, which satisfied the fortification criterion of surface buildings. This means the backfill mining did not affect nearby buildings. The results provide a theoretical basis for predicting surface deformation induced by backfill mining and its effective control

Facile Fabrication of Biomimetic Chitosan Membrane with Honeycomb-Like Structure for Enrichment of Glycosylated Peptides

In the study of glycoproteomics with mass spectrometry, certain pretreatments of samples are required for eliminating the interference of nonglycopeptides and improving the efficiency of glycopeptides detection. Although hydrophilic interaction chromatography (HILIC) has been developed for enrichment of glycosylated peptides, a plethora of hydrophilic materials always suffered from large steric hindrance, great cost, and difficulty with modifications of high-density hydrophilic groups. In this work, a 1 mm thick biomimetic honeycomb chitosan membrane (BHCM) with honeycomb-like accessible macropores was directly prepared by the freeze-casting method as an adsorbent for HILIC. The N-glycopeptides from trypsin digests of immunoglobulin G (IgG), mixture of IgG and bovine serum albumin (BSA), and serum proteins were enriched using this material and compared with a commercial material ZIC-HILIC. The biomimetic membrane could identify as many as 32 N-glycopeptides from the IgG digest, exhibiting high sensitivity (about 50 fmol) and a wide scope for glycopeptide enrichment. A molar ratio of IgG trypsin digest to bovine serum albumin trypsin digest as low as 1/500 verified the outstanding specificity and efficiency for glycopeptide enrichment. In addition, 270 unique N-glycosylation sites of 400 unique glycopeptides from 146 glycosylated proteins were identified from the triplicate analysis of 2 mu L human serum. Furthermore, 48 unique O-glycosylation sites of 278 unique O-glycopeptides were identified from the triplicate analysis of 30 mu g deglycosylated fetuin digest. These results indicated that the chitosan-based membrane prepared in this work had great potential for pretreatment of samples in glycoproteomics