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2022 ◽  
Author(s):  
Zhi-Hao Dong ◽  
Xiaohua Pan ◽  
Chao-Sheng Tang ◽  
Bin Shi

Abstract Rock weathering fractures in nature are complex and fracture healing is an effective strategy for rock weathering mitigation. This study is a first attempt to apply microbially induced calcium carbonate precipitation (MICP) technology in the healing of nature-weathering-like rough fractures (NWLRF). Sandstone was studied as an example due to it is a wide-spread construction, sculpture and monuments material all over the world. In order to achieve a high healing efficiency, a repeated mixture injection strategy was proposed. Based on a series of laboratory MICP injection experiments on four types of NWLRF, we systematically explored the fundamental micro-healing mechanism and the influence of factors including fracture aperture, characteristics of branch fractures, and cementation solution concentration. Experimental results demonstrated that MICP healing with the repeated mixture injection strategy had the ability to efficiently heal the penetrated NWLRF well with length in centimeter-scale and aperture in millimeter-scale, but cannot heal the non-penetrated branch fractures under low injection pressure. The repeated mixture injection strategy furtherly achieved a high apparent fracture healing ratio and a significant reduction of transmissivity. The apparent fracture healing ratios of all main fractures were higher than 80% and the maximum was 99.1%. Fracture transmissivity was reduced by at least three orders of magnitude from about 1×10-4 m2/s to less than 1×10-7 m2/s, and the highest reduction reached to four orders. For the aspect of the effects, larger cementation solution concentration, finer aperture and the existing of penetrated branch fracture were beneficial to improve the healing effect. Moreover, the MICP healing mechanism with high fracture healing ratio and significant reduction of transmissivity on sandstone NWLRF was also analyzed. The research results have important theoretical significance and technical guidance value for the disaster prevention and mitigation of rock weathering.


2022 ◽  
Vol 2152 (1) ◽  
pp. 012023
Author(s):  
Shuwei Lv ◽  
Xinming Zhang ◽  
Xiaodong Yang ◽  
Ying Zhai

Abstract A chemical etching technique is used to prepare a superhydrophobic surface with a honeycomb rough structure on the aluminum surface. Use SEM, Optical contact angle meter and Surface tension detector to characterize the etched aluminum substrate. After the 8th etching, the surface of the sample showed the morphology of micro/nano-scale honeycomb pores and protrusions, and the water contact angle (WCA) is 135°. After being modified with octadecanethiol methanol solution, WCA is 153.1°. After modification, the contact angle of the sample surface decreases with the increase of the glucose solution concentration. When the glucose solution concentration reaches 1000 mg/L, the superhydrophobicity is lost.


2021 ◽  
Author(s):  
Xiaoming Qian ◽  
Yu Zhang ◽  
Zhaodong Wang ◽  
X.-Grant Chen ◽  
Yong Li ◽  
...  

Abstract Dispersoid-strengthened Al-Mg-Si-Mn aluminum alloys were produced by twin-roll casting (TRC) and conventional mold casting (MC). An extra-low temperature homogenization was performed at temperature of 430 °C for 6 h, which was followed by uniaxial hot compression tests. The results showed that the as-cast TRC samples had a lower eutectic fraction with a smaller size and a higher solid solution concentration compared to the as-cast MC samples. During the extra-low temperature homogenization, a large number of α-Al(Fe, Mn)Si dispersoids precipitated, and the dispersoids in the TRC sample had a greater number density than those in the MC sample. Precipitation-free zone (PFZ) formed near the eutectic regions, TRC sample had a lower PFZ fraction than that of MC sample. The TRC samples yielded higher flow stresses of hot deformation than MC sample owing to the stronger dispersoid strengthening effect. Severe edge cracking occurred in the deformed MC samples due to the high fraction of coarse AlFeMnSi intermetallic particles, no edge crack formed in the TRC samples owing to its lower fraction and fine intermetallics which improved the hot workability of TRC sample.


NANO ◽  
2021 ◽  
Author(s):  
Jun Zhu ◽  
Yihong Ren

We propose a new method to determine the concentration of a sucrose solution based on Fano resonance, demonstrate that the [Formula: see text]-shaped resonator and rectangular resonator structures can realize the Fano resonance, observe higher sensitivity up to 2142 nm/RIU, and use the structure to measure the concentration of a sucrose solution. This work shows that the Fano resonance wavelength removed to longer wavelengths as the concentration of the solution increased, and the resolution of solution concentration is [Formula: see text], which can be used for measuring the concentration of solutions other than sucrose. This research is an important first step towards creating the industrial application of photon properties to extend photon polariton applications throughout the infrared.


2021 ◽  
Vol 9 ◽  
Author(s):  
Tianyi Sui ◽  
Lichao Li ◽  
Bin Lin ◽  
Yuhang Zhang ◽  
Benyang Zhang ◽  
...  

Ceramics can achieve superlubricity under water lubrication; however, their running-in period is long and application is rather limited by wear limit. Thus, zeolite imidazole ester skeleton (ZIF), an important branch of metal organic framework materials (MOFs), is expected to improve the tribological properties of lubricants and associated additives. As such, it has broad application prospects within the field. In this paper, ZIF-8 nanoparticles of varying concentrations were prepared and linked with amino functional groups. Specimens were used in silicon nitride self-matching pairs and their tribological properties were observed. After the experiment, friction surfaces were analyzed by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), and Fourier transform infrared radiation (FTIR). The experimental results have shown that ZIF-8 nanoparticles greatly reduced both friction and wear. Comprehensively considering running-in time, average COF during the whole process and smooth friction period COF, optimal performance was obtained for the ZIF-8 nanoparticle solution concentration of 1wt%. Furthermore, it was concluded that the lubrication properties of amino-modified ZIF-8 nanoparticles are significantly better compared to that of the unmodified ZIF-8. The anti-friction mechanism of ZIF-8 as a ceramic water lubrication additive was mainly through the filling and forming of nanoparticle film on the ceramic surface.


Author(s):  
Hesham Salem ◽  
Amany Abdelaziz ◽  
Aliaa Gamal ◽  
Ramy El Sabaa

A dependable, sensitive, basic and cheap spectrofluorimetric approach has been created for test of sulfur-containing drug; ixabepilone in bulk powder, vials and human plasma. The approach depends on the quenching effect of ixabepilone on the fluorescence intensity of acetoxymercuric fluorescene (AMF) reagent at λem of 530 nm and λex of 500 nm. Parameters which will control the reaction such as pH, AMF solution concentration, temperature, time and solvents were examined and optimized. According to the optimized conditions, the proposed approach was practiced over the concentration area of 20-100 ng mL-1 with adequate linearity (r = 0.9998). The developed approach was approved confirming to ICH rules in terms of accuracy, precision, linearity, LOD and LOQ. The proposed approach was practiced to analyze ixabepilone in Ixempra® vials with satisfactory recovery % of 99.89 and RSE% of 1.24. The results achieved were compared to those achieved by an already reported HPLC approach.


Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4312
Author(s):  
Pedro J. Rivero ◽  
Juan P. Fuertes ◽  
Adrián Vicente ◽  
Álvaro Mata ◽  
José F. Palacio ◽  
...  

In this work, a one-step electrospinning technique has been implemented for the design and development of functional surfaces with a desired morphology in terms of wettability and corrosion resistance by using polycaprolactone (PCL) and zinc oxide nanoparticles (ZnO NPs). The surface morphology has been characterized by confocal microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM) and water contact angle (WCA), whereas the corrosion resistance has been evaluated by Tafel polarization curves. Strict control over the input operational parameters (applied voltage, feeding rate, distance tip to collector), PCL solution concentration and amount of ZnO NPs have been analyzed in depth by showing their key role in the final surface properties. With this goal in mind, a design of experiment (DoE) has been performed in order to evaluate the optimal coating morphology in terms of fiber diameter, surface roughness (Ra), water contact angle (WCA) and corrosion rate. It has been demonstrated that the solution concentration has a significant effect on the resultant electrospun structure obtained on the collector with the formation of beaded fibers with a higher WCA value in comparison with uniform bead-free fibers (dry polymer deposition or fiber-merging aspect). In addition, the presence of ZnO NPs distributed within the electrospun fibers also plays a key role in corrosion resistance, although it also leads to a decrease in the WCA. Finally, this is the first time that an exhaustive analysis by using DoE has been evaluated for PCL/ZnO electrospun fibers with the aim to optimize the surface morphology with the better performance in terms of corrosion resistance and wettability.


Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4230
Author(s):  
Chung-Cheng Chang ◽  
Kwang-Ming Lee ◽  
Chia-Hong Huang

In this paper, it is reported that a metal-free and non-conjugated polymer, MA-PEG 8000-BADGE (MP8B), exhibits an antireflective property and substrate-dependent photoluminescence (SDP). MP8B was constructed from maleic anhydride, poly(ethylene glycol) and bisphenol-A diglycidyl ether. Self-assembled nanoparticles are found in MP8B and can prospectively act as scattering centers to improve light trapping and extraction. MP8B films prepared from MP8B solutions have been characterized by photoluminescence (PL), atomic force microscopy (AFM), tunnelling electron microscope (TEM), reflectance, transmittance, and UV-Vis absorption spectrum. MP8B films can suppress light reflection and enhance light transmission. The PL spectrum of MP8B film on ITO peaks at approximately 538 nm, spanning from 450 to 660 nm at a concentration of 25 mM. Meanwhile, the effects of concentration and substrate on the PL of MP8B films are also investigated in this study. Surface roughness becomes larger with concentration. A red shift of the PL spectrum is observed as solution concentration increases. Meanwhile, aggregation-caused quenching (ACQ) is insignificant. Moreover, the PL spectra of MP8B films show a substrate-dependent phenomenon due to dielectric screening. The optical band-gap energy of MP8B is approximately 4.05 eV. It is concluded that MP8B is a promising candidate for a host material, and its film can be utilized as a multifunctional layer (i.e., antireflective and light-scattering functions) for optoelectronic applications.


2021 ◽  
Vol 947 (1) ◽  
pp. 012018
Author(s):  
Nguyen Thi Truc Phuong ◽  
Tran Thi Hong Ngoc ◽  
Le Nguyen Quang Tu ◽  
Nguyen Quang Long

Abstract In this work, the metastable aqueous-aqueous interfacial approach was used to prepare MnO2 with enhanced surface area, which helps to save energy, decrease cost and protect the environment. The material characteristic success was proven through using powder X-ray diffraction for the crystalline properties and N2 adsorption-desorption isotherm for high surface area. The relationship between the calcination temperature and the crystallinity as well the specific material surface area was also interested. The catalytic decomposition of hydrogen peroxide was investigated by the closed system measuring produced oxygen. After the H2O2 decomposition comparison between synthesized samples and commercial MnO2 in terms of both the efficiency and the speed, the M-200 sample was considered as a typical sample with outstanding performance to examine the reaction conditions (H2O2 solution concentration, catalyst amount and reaction temperature). The optimal reaction condition results are 0.9% H2O2 solution concentration, 0.2g/L catalyst, and room temperature. Besides, the leaching test and the catalytic regeneration were also conducted.


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