A review on alloyed quantum dots and their applications as photocatalysts

Semiconductor driven artificial photocatalysis is the most sustainable technology towards addressing the growing energy and environmental pollution issues. In this context, alloyed quantum dots (QDs) are an emerging class of promising nanomaterials gathering tremendous attention in this area due to several beneficial features. Compared to other bulk semiconductors, alloyed QDs are cost-effective, stable, less-toxic with superior optoelectronic features, which significantly enhances their solar energy conversion efficiency. Herein, the present review summarizes the fundamentals of alloyed QDs, various synthesis techniques, and discusses optical as well as structural properties from data interpretation point of view taking suitably reported literature. Moreover, we have provided a comprehensive summary of recent state of art metal chalcogenides based alloyed QD systems towards H₂ evolution, CO₂ reduction, and pollutant degradation. Finally, the review discusses the associated challenges and future prospects of alloyed QDs with a special focus on preparation, property engineering, theoretical aspect, stability and other field application. Additionally, the overarching aim is to provide researchers an in-depth understanding in the field of alloyed QDs relating to synthesis, characterisation, and promotes their photocatalytic applications, and can foster as a manual to future researchers.     

The study of ignition and emission characteristics of hydrogen-additive hydro-processed renewable diesel

This study was conducted to understand the effects of hydrogen (H₂) addition on the combustion and emission characteristics of hydro-processed renewable diesel. Experiments were performed in a constant volume combustion chamber (CVCC) at varying H₂ concentrations (0%, 5%, and 10% (by vol.)) relative to air (100%, 95%, and 90% (by vol.)), initial temperatures (T_ini) of 600, 650 and 700 K, equivalence ratios (φ) of 0.5, 1.0, and 1.5 and a fixed initial pressure (P_ini) of 10 bar. Overall, HRD has lower ignition delay (ID) and total ID. However, H₂ addition to HRD delayed the fuel's auto-ignition due to excess H₂ oxidation (H₂+OHhttps://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/dbnd.gif" alt="double bond">H₂O + H) reaction taking place, which turns the chain reactions from branching to propagation, resulting from increasing in ID. Moreover, increasing of H₂ concentrations enhanced the maximum pressure rise (P_max) and heat release rate (HRR), whereas carbon dioxide (CO₂) and unburned hydrocarbon (HC) were decreased due to the higher magnitude of the lower heating value of H₂ than that of pure HRD. Since H₂ itself is a carbon-free molecule, the carbon content of the fuel is reduced. H₂ has the characteristics of fast combustion, resulting in a more flammable and complete mixture, which also makes HC emissions to become lower. However, the higher energy density of H₂ significantly raises the combustion temperature, and subsequent nitrogen oxides (NOx) were increased. The kinetic modeling predictions revealed that the IDs for HRD-H₂ were elongated due to the increased hydroperoxyl (HO₂) and hydrogen peroxide (H₂O₂) mole fractions which led to improved stability.     

低致敏蛋白Ara h 1复合益生菌发酵花生乳制备工艺优化

目的:研制低致敏复合乳酸菌发酵花生乳。方法:利用试剂盒测定不同品种花生中的粗蛋白含量及Ara h 1含量，选取Ara h 1含量最低的花生品种制作发酵乳；以接菌量、接菌种类、发酵时间及糖添加量为考察因素，Ara h 1含量为测定结果，采用响应面法优化致敏蛋白Ara h 1含量下降最多的发酵花生乳制备工艺；制作复合益生菌发酵花生乳，并对产品的口感、组织状态和风味进行感官评价。结果:当接菌量为4%、接种嗜热链球菌和保加利亚乳杆菌、发酵4 h、糖添加量为6%时，发酵花生乳中的主要过敏原Ara h 1减少70%,含量为48μg/g,且感官评分达到80分。结论:经工艺优化获得了致敏蛋白Ara h 1含量低，凝乳效果好，口味怡人的复合益生菌发酵花生制品。     

Tribological properties of h‐BN nanoparticles as lubricant additive on cylinder liner and piston ring

Friction and wear behaviour of different concentrations of hex‐boron nitride (h‐BN) nanoparticles in engine oil of grade SAE 20W50 were studied at various loads. These tribological studies were conducted using a four‐ball wear test machine and a pin‐on‐disc universal tribometer. Anti‐wear properties of SAE 20W50 + h‐BN were studied on the four‐ball wear test machine as per ASTM D4172 standard. Friction and wear properties of SAE 20W50 + h‐BN on piston ring and cylinder liner tribo‐pair were studied using the universal tribometer. Nanoparticles of h‐BN mixed in lubricant showed excellent tribological performance. In most of the cases, h‐BN nanoparticles as additive reduced the wear loss by 30–70% at various loads. The minimum value of coefficient of friction (0.0401) was found with SAE 20W50 + 3 wt% of h‐BN at normal load of 100 N. Scanning electron microscopy and Raman spectroscopy were used for characterisation of h‐BN and wear scars. Copyright © 2016 John Wiley & Sons, Ltd.