Uniaxial dry pressing (DP) and slip casting (SC) were used to form green bodies of nanocrystalline 8 mol% yttria‐stabilized zirconia powder processed via the glycine‐nitrate combustion method. The SC method was shown to be a more efficient, yielding more homogenous green bodies with higher green density (60% theoretical density) which contained smaller pores with narrower distribution. Improved green properties resulted in lowering the sintering temperature of SC bodies by about 200°C compared with DP compacts. Consequently, the grain growth in sintered bodies formed by SC was relatively abated. By taking the benefits of the wet conformation method, the final grain size of nearly full dense (>97% TD) structures was reduced by 39% (i.e. from 2.15 to 1.3 μm). To reveal the effect of sintering technique, DP bodies were sintered via both microwave and two‐step sintering methods. While the grain size of two‐step sintered samples was <300 nm, sintering via microwave radiation yielded a nearly full dense structure with a mean grain size of 0.9 μm. The results show that conventionally sintered SC bodies posses higher indentation fracture toughness (FT) (∼3 MPa·m1/2) compared with DP samples (1.6 MPa·m1/2). Interestingly, it was shown that, without applying any modified sintering technique, the hardness and FT of SC bodies with coarser structures are completely close to those of samples sintered via microwave heating.
Zeolitic imidazolate framework-8 (ZIF-8) was used as an adsorbent for the removal of toluene in its gas phase at different relative humidity (RH). High-purity ZIF-8 with an average particle size of 0.64 µm synthesized from an aqueous solution at room temperature, and then characterized by X-ray diffraction (XRD), fourier transform infrared (FT-IR) and scanning electron microscopy (SEM) techniques. Dynamic adsorption (continuous mode) experiments of toluene on ZIF-8 were studied using breakthrough curves. The effects of thermal pretreatment (activation) under dry air and N 2 atmospheres on the adsorbent performances was studied. ZIF-8 activated at 300 • C for 3 h under dry air showed the highest adsorption capacity of 562.17 mg•g −1. Furthermore, it was observed that the adsorption of toluene on ZIF-8 was significantly decreased at 80% RH. The experimental data of dynamic adsorption well fitted into the Thomas and Yan mathematical models.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
trans,trans‐Muconic acid has been widely used as a biomarker in biological monitoring of benzene‐exposed workers during routine occupational health services. In the present study, a novel microextraction technique, in‐syringe ionic liquid‐dispersive liquid–liquid microextraction, was implemented for preconcentration of trans,trans‐muconic acid followed by analytical determination by high‐performance liquid chromatography with ultraviolet detection. Moreover, the important variables affecting the performance of applied microextraction technique including needle diameter, volume of the spiked sample, volume of the ionic liquid, salt addition, rotation speed of centrifugation, centrifuge time, and ultrasonic time were optimized by experimental design. A good linear relationship was observed at the range of 0.032–10 μg/mL between the peak area and the concentration levels (R2 = 0.9997). The limit of detection and extraction recovery for trans,trans‐muconic acid were 0.011 μg/mL and >96.2%, respectively. This method provided easy and rapid analysis of low amounts of trans,trans‐muconic acid in human urine with simple equipment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.