Study on preformed and in situ spinel containing alumina castable for steel ladle: Effect of fume silica content

In the present study, the effect of fume silica content on preformed and in situ spinel containing alumina spinel castable was studied by varying fume silica content at 1 and 4 wt.%. Spinel content for preformed alumina spinel castables varied from 10 to 30 wt.% and MgO content for in situ alumina spinel castables varied from 2.8 to 8.4 wt.%, respectively, and the distribution coefficient (q value) was maintained at .21 and .29 as per Dinger and Funk model. Different castable compositions were processed as per conventional processing technique and further evaluated for densification and strength studies after heat treatment at 110, 1000, and 1550°C. Fired samples at 1550°C were further evaluated for the hot modulus of rupture study at 1400°C and phase analysis study of the matrix phase. Also, the fired samples were studied for microstructural evaluation.     

Microstructure and mechanical characterization of Cu–Ni/Al2O3 nanocomposites fabricated using a novel in situ reactive synthesis

Chemical-based synthesis of co-formed oxide (CuO–NiO–Al₂O₃) nanoparticles, followed by selective hydrogen reduction of the Cu and Ni oxides and ultimately consolidation into pellets, produced various compositions of Cu–Ni/Al₂O₃ nanocomposites. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy analyses were used to characterize the powders. The generated powders ranged in size from 20 to 70 nm, with a considerable presence of agglomerates. According to SEM examination, the powders were homogeneous in shape and particle size. Cold pressed nanocomposite powders were sintered for 2 h at 950 °C. SEM with energy dispersive spectroscopy (EDS) was also used to study the microstructure of the sintered specimens. In addition, the physical and mechanical properties of sintered specimens were studied. When the Al₂O₃ content increased, a more uniform distribution of nanosized Al₂O₃ particles in the Cu–Ni matrix was attained, resulting in a reduction in particle size. The results also demonstrated that as the Al₂O₃ concentration was raised, the microhardness and compressive strength of the nanocomposites rose by 74% and 67% compared to pure alloy, with the exception of fracture strain, which decreased dramatically.     

In-situ hydrophobic environment triggering reactive fluorescence probe to real-time monitor mitochondrial DNA damage

Mitochondrial DNA has a special structure that is prone to damage resulting in many serious diseases,such as genetic diseases and cancers.Therefore,the rapid and specific monitoring of mitochondrial DNA damage is urgently needed for biological recognition.Herein,we constructed an in situ hydrophobic environment-triggering reactive fluorescence probe named MBI-CN.The fluorophore was 2-styrene-1H-benzo[d]imidazole,and malononitrile was introduced as a core into a molecule to initiate the hydrolysis reaction in the specific environment containing damaged mitochondrial DNA.In this design,MBI-CN conjugates to mitochondrial DNA without causing additional damages.Thus,MBI-CN can be hydrolyzed to generate MBI-CHO in an in situ hydrophobic environment with mitochondrial DNA damage.Meanwhile,MBI-CHO immediately emitted a significative fluorescence signal changes at 437 and 553 nm within 25 s for the damaged mitochondria DNA.Give that the specific and rapid response of MBI-CN does not cause additional damages to mitochondrial DNA,it is a potentially effective detection tool for the real-time monitoring of mitochondrial DNA damage during cell apoptosis and initial assessment of cell apoptosis.     

Reinforced chloroprene rubber by in situ generated silica particles: Evidence of bound rubber on the silica surface

Nano silica is generated in situ inside the uncrosslinked chloroprene rubber (CR) by the sol‐gel reaction of tetraethoxysilane (TEOS). This results in appreciable improvement in mechanical properties of the CR composites at relatively low filler content. Furthermore, exploitation of reactive organosilanes, γ‐aminopropyltrimethoxysilane (γ‐APS) in particular, in the silica synthesis process facilitates growing of spherical silica particles with a size distribution in the range of 20‐50 nm. The silica particles are found to be uniformly dispersed and they do not suffer from filler‐filler interaction. Additionally, it is observed that the silica particles are coated by silane and rubber chains together which are popularly known as bound rubber. The existence of the bound rubber on silica surface has been supported by the detailed investigations with transmission electron microscopy (TEM), energy filtered transmission electron microscopy (EFTEM) and energy dispersive X‐ray spectroscopy (EDAX). The interaction between rubber and silica, via bi‐functionality of the γ‐APS, has been explored by detailed FTIR studies. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43717.     

In‐situ Preparation of a Porous Copper Based Nano‐Energetic Composite and Its Electrical Ignition Properties

In this paper, the in‐situ preparation and characterization of a porous copper‐sodium perchlorate energetic nano‐composite (PCu/NaClO₄) and its electrical ignition properties are presented. Porous copper was in‐situ produced by electro‐deposition on a Ni/Cr alloy wire, which acts as a cathode during the electro‐deposition. The PCu/NaClO₄ nano‐composite was produced by dipping the bridge with porous copper into a saturated sodium perchlorate acetone solution. SEM, EDS, and XRD were used to characterize the composite and DSC was used to study the thermal decomposition of the composite. The copper grain size was reduced by using additives such as CTAB in the electrolyte. The PCu/NaClO₄ nano‐composite on the bridge can be ignited by feeding a current through the bridge and the ignition delay time and electrical ignition sensitivity were measured.     

Demonstration of In Situ Radio‐Frequency Heating at a Former Industrial Site

In situ radio‐frequency heating (ISRFH) combined with soil vapor extraction was demonstrated at a contaminated field site of a former hydrotreatment plant in Zeitz near Leipzig. The project was carried out in several phases including cold soil vapor extraction for comparison. During the test, a soil volume of about 300 m³ was heated to an average temperature of 54 °C. As expected, the extraction rate for hydrocarbons (especially the main contaminant benzene) was markedly enhanced by soil heating. Furthermore, microbial degradation of organic compounds was supported. Although a total amount of approximately 1.4 t of hydrocarbons was removed from the soil, the demonstration project was not aimed at complete remediation of the site. Conditions limiting the extent of cleanup are discussed in detail and conclusions for an efficient application of ISRFH in soil remediation are derived whereas experiences from other sites are also implied.     

Fabrication and in vitro investigation of nanohydroxyapatite,chitosan, poly(L‐lactic acid) ternary biocomposite

The nanohydroxyapatite/chitosan/poly(L ‐lactic acid) (HA/CS/PLLA) ternary biocomposites were prepared by blending the hydroxyapatite/chitosan (HA/CS) nanocomposites with poly(L ‐lactic acid) (PLLA) solution. Surface modification by grafting D ‐, L ‐lactic acid onto the HA/CS nanocomposites was designed to improve the bonding with PLLA. The FTIR and ¹³C‐NMR spectrum confirmed that the oligo(lactic acid) was successfully grafted onto the HA/CS nanocomposites, and the time‐dependent phase monitoring showed that the grafted copolymers were stable. The TEM morphology of the HA/CS/PLLA ternary nanocomposites showed that nano‐HA fibers were distributed homogeneously, compacted closely and wrapped tightly by the CS and PLLA matrix. The ternary biocomposites with the HA content of 60 and 67 wt % exhibited high compressive strength of about 160 MPa and suitable hydrophilicity. The in vitro tests exhibited that the ternary biocomposites have good biodegradability and bioactivity when immersed in SBF solutions. All the results suggested that the n‐HA/CS/PLLA ternary biocomposites are appropriate to application as bone substitute in bone tissue engineering. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Superior ammonia sensing properties of PET-supported polyaniline/reduced graphene oxide/zinc ferrite ternary nanocomposite thin film at room temperature

This article introduces a ternary nanocomposite-based flexible thin film ammonia sensor developed on transparent polyethylene terephthalate (PET) substrate in the well-known in situ chemical oxidative polymerization technique. The nanocomposite consists of three different materials: polyaniline (PANI), reduced graphene oxide (rGO), and zinc ferrite (ZF). Keeping the PANI amount constant, seven PANI/rGO/ZF (PRZ) samples are produced by performing stoichiometric variation between rGO and ZF. Later on, various structural, morphological, and spectroscopic analysis of all the composite materials is accomplished with field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and ultraviolet–visible spectroscopy (UV–Vis). The sensing performance of the as-produced sensors toward ammonia (NH₃) is examined in the concentration range from 250 ppb to 100 ppm. The study reveals the excellent sensing ability of the PRZ3 sensor (rGO = 30%, ZF = 20%) achieving minimum and maximum responsivity values of ~51% and ~1052%, respectively, at the lowest (250 ppb) and highest (100 ppm) concentration of ammonia. The sensor also exhibits admirable repeatability, good dynamic responsivity, rapid response (t_res ~2.9–5 s), moderately faster recovery (t_rec ~37.9–69.7 s), superb linearity against ppm variation (R² ~ 0.989), low detection limit (~123 ppb), and exceptional selectivity toward ammonia. The substrate temperature variation divulges that room temperature (30°C) is the ideal temperature for getting outstanding responsivity of the sensor. The study is further accompanied by humidity variation in the incoming air and bending flexibility test of the substrate. A compulsory and legitimate model regarding the sensing mechanism is presented at the end.     

POE/SAN的原位增容

通过扭矩测定,傅里叶变换红外光谱、差示扫描量热法分析等方法研究了苯乙烯-丙烯腈共聚物(SAN)与聚烯烃弹性体(POE)大分子间的Friedel-Crafts烷基化反应。结果表明:适量无水AlCl3可以引发SAN与POE发生Friedel-Crafts烷基化反应,生成的POE-g-SAN接枝共聚物起到了原位增容POE/SAN共混物的作用,提高了其力学性能;当m(POE)/m(SAN)为60.0∶40.0,反应温度为180℃,AlCl3用量为0.4 phr时,POE/POE-g-SAN/SAN共混物性能较好;进一步提高AlCl3用量,SAN分子结构中侧链氰基与铝离子络合作用增强,导致SAN分散相聚集,POE/POE-g-SAN/SAN共混物刚性下降。     

Combined recovery of valuable metals from LiFePO4–LiCoO2 system without adding oxidant and reductant

Based on the oxidation of ferrous ions in lithium iron phosphate and reduction of trivalent cobalt ions in lithium cobaltate, an innovative combined recovery process of lithium iron phosphate and lithium cobaltate powders is proposed. The effects of leaching conditions on leaching performance are studied and the optimal leaching conditions are obtained. Under these conditions, the leaching efficiencies of lithium and cobalt ions reach up to 99.92% and 81.11%, respectively. After removing ferric ions from leachate, the cobalt and lithium ions are separately recovered from the leaching solution. The final precipitation rate of cobalt ions is up to 97.71% with the purity of cobalt oxalate as 99.94%. In addition, the precipitation rate of lithium ions is 78.54% and the purity of lithium carbonate reaches up to 99.94%. Finally, the reaction path and mechanism for the combined recovery of lithium iron phosphate–lithium cobaltate system are preliminary investigated.