Synthesis of Salt Responsive Spherical Polymer Brushes

A facile preparation of novel salt responsive spherical polymer brushes (SPB) consisting of a carbon spheres core and a shell of sodium polystyrene sulfonate (PSSNa) was described. The SPB were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The radius R of carbon spheres and hydrodynamic radius Rh of SPB were ca. 370 nm and 785 nm, respectively. The brushes had Mw of 393600 g/mol with polydispersity Mw/Mn of 1.58. Furthermore, the dependence of PSSNa brushes on ionic strength and pH was investigated

Harnessing Path Optimization to Enhance the Strength of Three-Dimensional (3D) Printed Concrete

The path-dependent strength of three-dimensional printed concrete (3DPC) hinders further engineering application. Printing path optimization is a feasible solution to improve the strength of 3DPC. Here, the mix ratio of 3DPC was studied to print standard concrete specimens with different printing paths using our customized concrete 3D printer, which features fully sealed extrusion and ultrathin nozzles. These paths include crosswise, vertical, arched, and diagonal patterns. Their flexural and compressive strengths were tested. In order to verify the tested results and expose the mechanism of strength enhancement, digital image correlation (DIC) was used to capture the dynamic gradual fracture in the flexural tests. Also, the meso- and microstructures of the 3D-printed concrete specimens were pictured. The results reported here show that arched-path concrete has 30% more flexural strength than others because it makes better use of filament-wise strength. The findings here provide a pathway to improve the strength of 3D-printed concrete by path optimization, boosting 3DPC’s extensive application in civil engineering

Adsorption of Lead with Silica Gel Modified with Polyamidoamine Dendrimer and Thiomalic Acid

New adsorbents PAMAM-n.0TMSG (n=1,2,3,4) with thiomalic acid as functional group has been prepared based on polyamidoamine dendrimer modified silica gel and characterized with FTIR, SEM and TG. Microcolumn enrichment and measurement of Pb2+ with graphite furnace atomic absorption spectroscopy (GFAAS) was investigated with PAMAM-n.0TMSG (n=1,2,3,4) as adsorbent. The adsorption conditions were optimized. The increase of grafted generation of PAMAM-n.0TMSG could effectively improved the adsorption performance of adsorbents. The adsorption capacity of adsorbents was 14.42, 16.19, 20.79 and 25.32 mg g-1 respectively, With PAMAM-4.0TMSG as adsorbent, microcolumn enrichment and measurement of Pb2+ with GFAAS was proposed. The relative standard deviation (R.S.D.) was 1.4% (n=11) for 0.2 μg mL-1 of Pb2+. The limit of detection (LOD) of 2.9ng mL−1 was achieved. The proposed column enrichment method was applied for detection of Pb2+ in tap water and sea water samples successfully

Adsorption of Lead with Silica Gel Modified with Polyamidoamine Dendrimer and Thiomalic Acid

New adsorbents PAMAM-n.0TMSG (n=1,2,3,4) with thiomalic acid as functional group has been prepared based on polyamidoamine dendrimer modified silica gel and characterized with FTIR, SEM and TG. Microcolumn enrichment and measurement of Pb2+ with graphite furnace atomic absorption spectroscopy (GFAAS) was investigated with PAMAM-n.0TMSG (n=1,2,3,4) as adsorbent. The adsorption conditions were optimized. The increase of grafted generation of PAMAM-n.0TMSG could effectively improved the adsorption performance of adsorbents. The adsorption capacity of adsorbents was 14.42, 16.19, 20.79 and 25.32 mg g-1 respectively, With PAMAM-4.0TMSG as adsorbent, microcolumn enrichment and measurement of Pb2+ with GFAAS was proposed. The relative standard deviation (R.S.D.) was 1.4% (n=11) for 0.2 μg mL-1 of Pb2+. The limit of detection (LOD) of 2.9ng mL−1 was achieved. The proposed column enrichment method was applied for detection of Pb2+ in tap water and sea water samples successfully

Study on Evacuation Speed based on Psychological panic in Railway Tunnel

In order to probe the panic psychology effect on the evacuation characteristics and evacuation efficiency under an emergency such as a fire in a railway tunnel, this paper uses a combination of theoretical derivation and 3D simulation technology to study personnel evacuation, investigates the psychological panic effect coefficient of the evacuation speed under various situations such as different numbers of personnel and structural parameters in emergency rescue evacuation facilities (emergency rescue stations, emergency exits, shelters) of railway tunnels to determine the range of influence factors of crowd evacuation speed under psychological panic. Studies show that: ①Considering the effects of psychological panic factors, the speed of evacuation should increase by about 1.25 to 1.49 times, with an average of about 1.37 times; ②The panic reduction factor for the crowd evacuation time at the emergency rescue station of the railway tunnel is 0.8 ~ 1, and the panic reduction factor for the crowd evacuation time at the emergency exit and refuge is 0.75 ~ 1.05

Evaluation indicators for Integrated Coastal Management (ICM) in China: lessons learned from Xiamen

Integrated Coastal Management (ICM) initiatives spread all over the world to cope with declining conditions and intensifying user conflicts to achieve sustainable development of coastal resources and environment. A set of indicators with regard to sustainable development and governance aspects were developed in Xiamen to monitor the State of Coasts (SOC) under ICM implementation. In developing the evaluation indicators for Xiamen, a number of lessons were learned related to data compilation, indicator development, public participation and scaling up. The experience of Xiamen was believed to contribute to develop evaluation indicators for ICM in China

Polyethyleneimine-Functionalized Carbon Nanotubes Enabling Potent Antimycotic Activity of Lyticase

In this work, the positively-charged polymer polyethyleneimine was used to functionalize carbon nanotubes and activated carbon to load antimycotic enzyme lyticase. Interestingly, polyethyleneimine played a dual role functionalizing carbon materials to synergistically enhance antimycotic activity of loaded lyticase as well as exhibiting its own apparent antimycotic activity, where the enhanced enzymatic activity of loaded lyticase on functionalized carbon nanotubes was more than 2.8 times as high as the activity of free enzyme in solution. The actual activity of loaded lyticase on functionalized carbon nanotubes was applied with Penicillium janthinellum, exhibiting much faster digesting lysis of the bacteria in comparison with free lyticase. The synergistic and potent antimycotic activities from combined action of antimycotic lyticase and polyethyleneimine on carbon nanotubes provides a new antimycotic protection for medicine, food industry, and other biochemical processes