Branched micro/nano Se was prepared by the redaction of L-Cys•HCl and H2SeO3 in hydrothermal method, as β-CD was used as soft template. The structures of products were characterized by SEM, TEM and XRD. Some important factors influencing the morphology of products were studied and discussed, including the amounts of soft template, the reaction temperature and the reaction time. The results showed that external causes had a potent effect on the morphology of micro/nano Se. The uniform branched micro/nano Se prepared under the optimal reaction condition was rhombohedral trigonal selenium t-Se0, but its crystallinity degree was low.
The Olefin aromatization is an important method for the upgrade of catalytic cracking (FCC) gasoline and production of fuel oil with high octane number. The nano-ZSM-5 zeolite was synthesized via a seed-induced method, a series of modified nano-ZSM-5 zeolite samples with different Ga deposition amount were prepared by Ga liquid deposition method. The XRD, N2 physical adsorption, SEM, TEM, XPS, H2-TPR and Py-IR measurements were used to characterize the morphology, textural properties and acidity of the modified ZSM-5 zeolites. The catalytic performance of the Hexene-1 aromatization was evaluated on a fixed-bed microreactor. The effects of Ga modification on the physicochemical and catalytic performance of nano-ZSM-5 zeolites were investigated. The Ga species in the modified nano-ZSM-5 zeolites mainly exist as the form of Ga2O3 and GaO+, which provide strong Lewis acid sites. The aromatics selectivity over Ga modified nano-ZSM-5 zeolite in the Hexene-1 aromatization was significantly increased, which could be attributed to the improvement of the dehydrogenation activity. The selectivity for aromatics over the Ga4.2/NZ5 catalyst with suitable Ga deposition amount reached 55.4%.
Public-Private Partnerships (PPPs) are mostly presented as a means to introduce efficient procurement methods and better value for money to taxpayers. However, the complexity of the PPP mechanism, their lack of transparency, accounting rules and implicit liabilities make it often impossible to perceive the amount of public expenditure involved and the long-run impact on taxpayers, providing room for fiscal illusion, i.e., the illusion that PPPs are much less expensive than traditional public investments. This psaper, thanks to a systematic review of the literature on the EU countries experience, tries to unveil the sources of this illusion by looking at the reasons behind the PPPs’ choice, their real costs, and the sources of fiscal risks. The literature suggests that PPPs are more costly than public funding, especially when contingent liabilities are not taken into account, and are employed as mechanisms to circumvent budgetary restrictions and to spend off-balance. The paper concludes that the public sector should share more risks with private sectors by reducing the amount of guarantees, and should prevent governments from operating through a sleight of hand that deflects attention away from off-balance financing, by applying a neutral fiscal recording system.
Dormancy is a state of lack of germination/sprouting in seed/tuber although required conditions (temperature, humidity, oxygen and light) are provided. Dormancy is based on hard seed coat dormancy or lack of supply and activity of enzymes (internal dormancy) necessary for germination/sprouting. Dormancy is an important factor limiting production in many field crops. Several physical and chemical pretreatments to production material (seed/tuber) are carried out for overcoming dormancy. Physical and physiological dormancy can be found together in some plants and this event makes it difficult to provide high frequency healthy seedling growth. Whereas, emerging of all production material (seed, tuber) sown/planted and forming healthy seedling are prerequisites of plant production.
In this paper, a detailed mineralogical and genesis investigation have been carried out in the seven locations of the Iron Ore in Hazara area. Thick bedded iron ore have been observed between Kawagarh Formation and Hangu Formation i.e., Cretaceous-Paleocene boundary. At the base of Hangu Formation, variable thickness of these lateritic beds spread throughout the Hazara and Kohat-Potwar plateau. This hematite ore exists in the form of unconformity. X-ray diffraction technique (XRD), X-ray fluorescence spectrometry (XRF), detailed petroghraphic study and scanning electron microscope (SEM) techniques indicated that those iron bears minerals including hematite, chamosite and quartz, albite, clinochlore, illite-montmorillonite, kaolinite, calcite, dolomite, whereas ankerite are the impurities present in these beds. The X-ray fluorescence (XRF) results show that the total Fe2O3 ranges from 39 to 56%, with high silica and alumina ratio of less than one. Beneficiation requires for significant increase in ore grade. The petroghraphic study revealed the presence of ooids fragments as nuclei of other ooids with limited clastic supply, which indicate high energy shallow marine depositional setting under warm and humid climate. The overall results show that Langrial Iron Ore is a low-grade iron ore which can be upgraded up to 62% by applying modern mining techniques so as to fulfill steel requirements of the country.
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