Lab scale optimization of various factors for photocatalytic hydrogen generation over low cost Cu0.02Ti0.98O2-δ photocatalyst under UV/Visible irradiation and sunlight

We have demonstrated earlier that maximum H₂ generated @ 1.167 l/h/m² over Cu_0.02Ti_0.98O_2-δ photocatalyst with apparent quantum efficiency, AQE of 7.5% and solar fuel efficiency, SFE of 3.9% under sunlight. With an aim to scale-up the solar photocatalytic hydrogen process to pilot plant, optimization studies at lab scale as well as in upscaled photoreactors were performed over Cu_0.02Ti_0.98O_2-δ, photocatalyst under UV/visible and sunlight. Cu_0.02Ti_0.98O_2-δ was synthesized by facile sol-gel route and characterized by relevant techniques. Several operational parameters were investigated in order to finalize the conditions which are most favourable for photocatalytic hydrogen yield. Factors such as photocatalyst loadings, v/v concentration of sacrificial reagent, replacement of methanol by industrial waste glycerol, role of different configuration of light source with reactor, effect of stirring during the photocatalytic reaction, effect of fluctuations of solar flux at hourly basis, illumination area on hydrogen yield were studied. Contribution of each factor in determining the hydrogen yield was quantified. Relative standard deviation in hydrogen yield as a function of each factor was estimated. Our findings suggest that in addition to catalyst loadings and sacrificial reagent, improved dispersion of photocatalyst obtained by stirring the reaction mixture in horizontal geometry resulted in enhanced H₂ yield. Hydrogen yield obtained at lab scale can be appropriately extrapolated with respect to illumination area instead of weight of photocatalyst. A relative standard deviation (RSD) of ± 3.82% and ± 4.53% in H₂ yield was calculated for sunny and cloudy days in time zone of 10.30–16.30 h IST. Deviation of H₂ yield was more on cloudy days and beyond 16:30 h. These studies have provided a daily window of 11:00–15:00 h to be utilized throughout the year for a commercial scaled up process, prohibiting the illumination during less productive hours of the day for shaping the improved economics of solar hydrogen generation. Our results obtained at lab scale would be useful to perform sunlight driven scaled –up photocatalytic process using low cost visible light efficient photocatalyst, Cu_0.02Ti_0.98O_2-δ.     

Microemulsion synthesis of ms/tz-BiVO4 composites: The effect of pH on crystal structure and photocatalytic performance

In this work, BiVO₄ composites, containing the tetragonal zircon phase (tz-BiVO₄), and monoclinic scheelite phase (ms-BiVO₄), were synthesized using the microemulsion method. The effect of pH on phase composition and photocatalytic activity were investigated. Based on X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), a ms/tz-BiVO₄ composite forms at pH = 1.0 and pure ms-BiVO₄ is obtained in the pH range 4.0–10.0. The three primary steps in preparing BiVO₄ were monitored by optical microscopy and the role played by the microemulsion on the phase composition of BiVO₄ is explained. Photoluminescence spectroscopy (PL), UV–visible diffuse reflectance spectroscopy (UV-DRS), Brunauer-Emmett-Teller (BET), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) were employed to characterize the physical and chemical properties of BiVO₄ composites. The composite formed at pH = 1 exhibited the lowest hole-electron (h⁺-e^-) recombination rate, resulting in the highest photocatalytic activity towards microcystin-LR (MC-LR), with near 100% removal of MC-LR in 5 h. ESR and trapping experiments indicated that MC-LR degradation was mediated primarily by hydroxyl radicals (•OH), superoxide radicals (O₂^•−) and photogenerated holes (h⁺).     

Effect of microstructure on the fatigue crack growth behaviour of a near-α Ti alloy

Fatigue crack growth behaviour of Ti–6Al–2Zr–1.5Mo–1.5V (VT-20 a near-α Ti alloy) was studied in lamellar, bimodal and acicular microstructural conditions. Fatigue crack growth tests at both increasing and decreasing stress intensity factor range values were performed at ambient temperature and a loading ratio of 0.3 using compact tension samples. Lamellar and acicular microstructures showed lower fatigue crack growth rates as compared to the bimodal microstructure due to the tortuous nature of cracks in the former and the cleavage of primary α in the latter. The threshold stress intensity factor range was highest for acicular microstructure.     

预裂爆破减震机理及效果分析

本文将爆炸应力波以预裂缝高度将其分成上部应力波和底部应力波，分别应用节理刚度模型和应力波理论解释了预裂缝对其减弱和阻隔作用，从理论上说明了预裂爆破的减震机理，并进一步讨论了预裂缝宽度的影响和减震效果分析。     

GPJ-120型加压过滤机在太原选煤厂的应用

分析了太原选煤厂浮选精煤脱水系统存在的问题，介绍了应用加压过滤机后的工艺效果，实践证明，加压过滤机过滤处理能力大，滤饼水分低，自动化程度高。     

某铜矿5401残矿溶浸采矿初步研究

本文简要地介绍了本溶浸研究组对5401残矿溶浸采矿初步研究结果。内容包括工艺矿物学研究、浸出原理、浸出方法、浸出措施及效果。本文的发表将对高泥矿石的原地破碎浸出有一定的参考价值。     

独头工作面通风降温新方法及效果分析

在贯穿风流温度较低的矿井，可用通风的方法解决独头作业面的降温问题，并在分析常规局部通风存在诸多缺点的基础上，提出了用小型高压鼓风机与刚性轻质小断面PVC风筒配合的沐浴局部通风降温新方法，并对该方案的效果进行了分析和计算。结果表明，该 方案在理论上是可行的，并具有许多显著的优点。     

金川二矿区围岩-充填体应力场的本构关系

本文结合金川二矿区充填机理研究工作的长期实践,应用粘弹塑性理论和增量计算方法,论述了围岩、矿体、充填体三者共同吻合变形作用的本构关系,较好地解决了金川二矿区一号矿体下向大面积胶结充填体和岩体共同作用时围岩的稳定性问题,计算结果与现场观测的围岩变形位移基本符合。为二矿区一号矿体采用大面积下向胶结充填、沿走向连续回采而不留间隔矿柱回采提供了理论依据。本项成果已在金川二矿区应用并取得了明显的效益。     

影响煤系高岭土表面改性效果的研究

通过分析改性煤系高岭土在橡胶中的补强作用及机理，研究了原料粒度、煅烧和改性剂配方对煤系高岭土表面改性效果的影响。高岭土粒度越小，与橡胶基体形成的界面层面积越大，补强效果越好。在同样的表面改性处理条件下，未煅烧煤系高岭土比煅烧高岭土的改性效果好，对橡胶的补强作用强。偶联剂类型和用量是影响表面改性的重要因素。     

山西煤矿安全监控系统建设

瓦斯是煤矿井工开采经常面临的主要灾害之一。具有突发性、严重的破坏性、残酷的杀伤性等特点。随着现代科技的不断发展，特别是数据处理技术在各行业的成熟应用，在煤炭行业通过计算机和数据处理技术管理煤矿井下生产活动和进行灾害报警预防的条件基本成熟。山西省煤炭工业局出台煤炭行业灾害治理政策，在全省范围内加大安全装备投入，对所有生产矿井进行安全监控系统建设和各级煤炭生产监督、安全监察部门进行网络建设．实行瓦斯网络化实时监控．对防止煤矿重大事故，提高安全生产，具有重大意义。