Ammonia–Nitrate Mixture Dominated by NH4+–N Promoted Growth, Photosynthesis and Nutrient Accumulation in Pecan (Carya illinoinensis)

Although ammonia–nitrogen (NH4+–N) and nitrate–nitrogen (NO3−–N) are the two main forms of N absorbed and utilized by plants, the preferences of plants for these forms are still unclear. In this study, we analyzed the growth, photosynthesis, and nutrients of pecan under different NH4+:NO3− ratios (0/0, 0/100, 25/75, 50/50, 75/25, 100/0) by indoor aerosol incubation. The results showed that additions of different N forms promoted the growth and development of pecan seedlings. When NO3−–N was used as the sole N source, it significantly promoted the ground diameter growth of pecan and increased the leaf pigment content and photosynthetic rate. The NH4+:NO3− ratio of 75:25 and NH4+–N as the sole N source significantly increased the soluble sugars in stems and roots, starch in leaves, stems and roots, soluble protein in leaves and stems, and soluble phenols in stems and roots. Additionally, the NH4+:NO3− ratio of 75:25 increased plant height, leaf number, root soluble protein, and leaf soluble phenol contents. In conclusion, regarding the physiological aspects of pecan growth, pecans are more inclined to use NH4+–N. Considering that the NH4+–N as the only N source may lead to nutrient imbalance or even toxicity, the NH4+:NO3− ratio of 75:25 was most favorable for the growth and development of pecan seedlings.

FIRE SAFETY OF HEAT-TRANSFER AGENTS FOR HEAT GENERATORS

Рассмотрены свойства двух групп теплоносителей, используемых для понижения рабочей температуры и для повышения рабочей температуры. В первую группу теплоносителей включены: этиленгликоль, диэтиленгликоль, триэтиленгликоль, пропиленгликоль, глицерин. Вторую группу теплоносителей составляют: дифенильная смесь, масло АМТ-300, масло ТЛВ-330, мобильтерм-600, дикумилметан, дитолилметан, тетрахлордифенил, тетракрезилсиликат, нафталин, тройная нафталиновая смесь, нитрит-нитратная смесь. Приводятся физико-химические и пожароопасные свойства названных теплоносителей, а также перечень профилактических противопожарных мероприятий и средств пожаротушения. There are considered the properties of two groups of heat-transfer agents used to reduce the operating temperature and to increase the operating temperature. The following substances are included in the first group of heat-transfer agents: ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, glycerin. The following substances are included in the second group of heat-transfer agents: diphenyl mixture, AMT-300 oil, TLV-330 oil, mobileterm-600, dicumylmethane, ditolylmethane, tetrachlorodiphenyl, tetracresyl silicate, naphthalene, triple naphthalene mixture, nitrite-nitrate mixture. There are cited the physicochemical and fire hazardous properties of the mentioned heat-transfer agents, as well as the list of preventive fire-fighting measures and fire-extinguishing facilities.

Growth and UV Absorption of 5 mol% Zn-Doped CeO2 Nanoparticle Synthesized with a Simple Precipitation Process

Nanoparticles of the 5 mol% Zn-doped CeO2 have been synthesized by simple precipitation process from aqueous/alcoholic solution of cerium nitrate and zinc nitrate mixture at room temperature. Dried precipitates were calcined at 300-700°C for 2 hours. The structure and growth of 5 mol% Zn-doped CeO2 was investigated using X-ray diffraction measurement. All the peaks in X-ray diffraction patterns are identified and indexed as single crystalline phase of cubic fluorite CeO2. The enhancement in calcination temperature increases the crystallite size from 5.51 to 15,56 nm and improves crystallinity of that nanoparticle. The low activation energy for crystallite growth of the 5 mol% Zn-doped CeO2 is found to be 10.85 kJ/mol. The UV-Vis spectrophotometer measurement shows the UV absorption property of the 5 mol% Zn-doped CeO2 enhanced with the increasing calcination temperature. The 5 mol% Zn-doped CeO2 nanoparticle calcined at temperature 600°C is found to be more effective as UV-blocker.