Preparation of a thick sponge-like structured amorphous silica ceramic coating on 6061 aluminum alloy by plasma electrolytic oxidation in TEOS solution

Plasma electrolytic oxidation (PEO) was performed on 6061 aluminum alloy in organosilicon electrolyte using a stepwise constant potential control method for 23 min. The resulting coating was a sponge-like structured amorphous silica ceramic with a thickness of about 130 μm. Its exceptional wear resistance was attributed to the high hardness of the silica ceramic and the low elastic modulus of the sponge-like structure. The corrosion resistance was enhanced by a dense layer of approximately 2 μm between the coating and the substrate. Impressively, the indentation depth of the PEO coating during nano-indentation tests was only 50–60% of that of 6061 aluminium alloy under varying loads, while the recovery depth of the PEO coating after unloading was 2.5–3.1 times greater than that of 6061 aluminium alloy. Due to its special composition and structure, the PEO coating caused serious wear to the high hardness Si₃N₄ friction balls during the friction and wear test. In the electrochemical tests, the coating reduced the corrosion current density from 1.056 × 10⁻⁵A·cm⁻² to 1.239 × 10⁻⁷A·cm⁻², while extending the passivation region from 0.322 V to 1.032 V.     

Electrical Resistance Tomography (ERT) applications to Chemical Engineering

Electrical Resistance Tomography (ERT) has the capability of offering time-evolving multidimensional comprehensive process knowledge, enrichment of fundamental process understanding and enhancement of the design and operation of process equipment by measuring the conductivity distribution within a process-plant of interest. This paper reviews the wide variety of previous work on ERT applications to Chemical Engineering. The applications are categorized based on the unit operations ERT has been applied to, the media under investigation, the purpose of ERT measurements and also other technologies used in conjunction with ERT. The aim of this taxonomy is to provide the reader with a general understanding of the current situation of ERT related research and proven applications in the Chemical Engineering field and to facilitate the recognition of research gaps for future investigation. Based on this detailed taxonomy and review the potential application of ERT to the milk powder processing industry was identified. Some results of the application of ERT to milk mixing/holding tanks and milk flow pipelines for the purpose of concentration and composition measurements, detection of abnormalities and faults, and multidimensional flow and velocity profile measurements have also been presented as a case study of using this taxonomy.     

Effect of dual reinforced ceramic particles on high temperature tribological properties of aluminum composites

The nature and distribution of hard ceramic particles in composite materials influences the properties to greater extent. In the present work, the role of hard ceramic reinforced particles on the tribological behaviour of aluminum metal matrix composites consisting of single (SRP) and dual reinforced particles (DRP) is studied at different temperatures. Zircon sand and silicon carbide particles of size 20–32 μm were used as reinforcement in commercial grade LM13 piston alloy. Composites of dual reinforced particles in aluminum matrix (DRP-AMCs) were developed by mixing 15 wt% reinforced particles by two step stir casting technique. The wear behaviour of DRP-AMCs and SRP-AMCs (single reinforced particles aluminum matrix composite) was investigated using a pin-on-disc method at high temperatures under dry sliding condition. The microstructural examination of developed composites shows globular and finely distributed eutectic silicon in the vicinity of the reinforced particles. Metallographic investigation revealed that the wear zone of the SRP composite consisted of a hardened layer, which is responsible for high wear loss observed in the SRP composite. The results further indicate a transition in the wear mode that occurs after 150 °C for all composites. Study reveals that the dual reinforcement of particles enhances the wear resistance as compared to single reinforced particles if mixed in a definite ratio. A combination of 3% zircon sand and 12% silicon carbide particle reinforced composite exhibits better wear resistance as compared to other combinations at all the temperatures for low and high loads both.     

Characterization of Sr1–xDyxCoO3–δ (x = 0.1, 0.2, 0.3) Cathode Materials for IT‐SOFCs

The cobaltate perovskites Sr_1–xDy_xCoO_3–δ (SDCO, x = 0.1, 0.2, 0.3) materials were synthesized and evaluated as cathode for La_0.8Sr_0.2Ga_0.8Mg_0.2O_3–δ solid electrolyte supported intermediate‐temperature‐solid oxide fuel cells (IT‐SOFCs). The crystal structure of Sr_0.9Dy_0.1CoO_3–δ was defined in the cubic Pm–3m space group (No. 221), Sr_0.8Dy_0.2CoO_3–δ and Sr_0.7Dy_0.3CoO_3–δ had a tetragonal I4/mmm structure. The electrical conductivities were all higher than 100 S cm^–1 in the temperature of 170–800 °C. The polarization resistance (R_p) and its activation energy (E_a) increased with increasing x. SEM analysis confirmed the porous microstructure of the SDCO cathodes and good LSGM|LDC|SDCO adherence. Sr_0.9Dy_0.1CoO_3–δ exhibited the best cathode characteristics with a maximum test‐cell power density of 841 mW cm^–2, being a high potential candidate of cathode material for IT‐SOFCs.     

纳米TiO2/PTFE复合材料的干摩擦磨损性能

利用磨损试验机、扫描电子显微镜等方法研究了表面处理与未处理纳米TiO2(质量分数为6％)填充聚四氟乙烯(PTFE)复合材料的干摩擦性能。结果表明,纳米TiO2能明显提高：PTFE耐磨性并改变其磨屑形成机理。表面处理纳米TiO2在PTFE中能较均匀分散。纳米TiO2填充PTFE复合材料的摩擦系数比PTFE稍大,纳米TiO2表面处理与否对PTFE复合材料的摩擦系数影响不大,但表面处理纳米TiO2填充聚四氟乙烯耐磨性比PTFE有显著提高,表面处理与表面未处理纳米TiO2填充PTFE复合材料的耐磨性比PTFE可分别提高7倍和3倍左右。导致PTFE磨损的重要机理是粘着磨损。     

Are Chemical Compounds Important for Soybean Resistance to <Emphasis Type="Italic">Anticarsia gemmatalis</Emphasis>?

The identification and quantification of flavonoids (rutin and genistin) present in extracts of soybean genotypes, and their effects on the biology and physiology of Anticarsia gemmatalis Hübner (Lep.: Noctuidae) were studied. Analysis of covariance and bicoordinate utilization plots were used to remove the effect of feeding time from pupal weight and consumption as well as to separate pre- and postingestive effects of treatment on A. gemmatalis growth. Genotypes PI 274454, PI 227687, and “IAC-100” extracts in general, caused higher mortality, negatively influenced initial larval and pupal weight, and elongated larval cycle. Larvae fed on the “IAC-100” extract diet ingested larger amounts of food per unit of time, but were less efficient in its conversion to biomass. Leaf extracts of PI 227687 had the largest concentration of rutin (quercitin 3-O-rhamnosylglucoside), followed by PI 274454, and “IAC-100”; PI 74454 also had the highest genistin (genistein 7-O-glucoside) content. The susceptible cultivar “BR-16” showed only a kaempferol-based flavonoid in its chemical profile, indicating that after successive crosses, secondary compounds responsible for plant defenses were eliminated. Genotypes PI 274454, PI 227687, and “IAC-100” showed accentuated resistance characteristics and were considered inadequate sources for the development of A. gemmatalis. Considering rutin and genistin concentration in these genotypes, it is suggested that flavonoids are important factors conferring resistance to A. gemmatalis.     

组合肋板式陶瓷换热器材质的研究

以耐火粘土、高矾土及滑石为原料研制了堇青石基陶瓷材料,并对其组织和性能尤其是抗热震性进行了研究。结果表明,堇青石基上分布着针状莫来石的材料具有更高的抗热震性。对评价换热器用陶瓷材料抗热震性参数进行了讨论,指出抗热震损伤参数R″″更适合于作为优选陶瓷换热器用材质的指标。     

冷环境下织物保暖性研究

本文研究了冷环境下的织物保暖性。在实验的基础上,对织物的原料、厚度、环境温度、组织等诸因素与热阻的关系作了分析,比较了诸因素对热阻的影响状况,并得到一系列关系图。为新产品在保暖性方面的相关设计提供了依据。     

UiO-66/PES混合基质超滤膜的制备及性能

以聚醚砜(PES)为主要膜材料、溶剂热法合成UiO-66并掺入铸膜液中,通过非溶剂相转化法(NIPS)制备了混合基质超滤膜.利用X射线衍射仪(XRD)、傅里叶红外光谱(FTIR)、扫描电镜(SEM)、接触角测量仪及原子力显微镜(AFM)对制备的UiO-66和混合基质膜进行表征.重点考察了UiO-66添加量对膜表面形貌、...     

Rational Optimization of Dihydropyrimidinone-Quinoline Hybrids as Plasmodium falciparum Glutathione Reductase Inhibitors

A series of dihydropyrimidinone-based antimalarial compounds were designed and synthesised based on the previously identified amide-based quinoline hybrids which showed good resistance reversal ability against the resistant strain of Plasmodium falciparum. The aromatic ring on the dihydropyrimidinone of the original hits was exchanged for a methyl group to bring the molecular weights below 500 Da and also determine the effect of the aromatic ring count on the resistance reversal ability of the hybrids. Apart from the previously used amide bond, the hybrid linker was also extended to the triazole linker. Although the triazole linker is synthetically easier to access, the use of an amide linker seems to have an activity advantage. The synthesised compounds in addition to the previously identified hits were subjected to molecular docking particularly targeting the orthosteric site of Plasmodium falciparum glutathione reductase (PfGR) protein. The ligand with the best binding interaction was rationally optimised to increase its suitability as a competitive inhibitor against the cofactor of the PfGR. Two of the optimised ligands showed better binding affinities than the cofactor while one of the two ligands displayed hydrophobically packed correlated hydrogen-bond which is very important in maintaining the ligand stability within the protein. In silico ADME predictions of the synthesised compounds indicate that these compounds possess good pharmacokinetic properties.