Alleviation of Heat Stress in Tomato by Exogenous Application of Sulfur

Temperature is a key factor influencing plant growth and productivity, however sudden increases in temperature can cause severe consequences in terms of crop performance. We evaluated the influence of elementary sulfur application on the physiology and growth of two tomato genotypes (“Ahmar” and “Roma”) grown in two growth chambers (at 25 and 45 °C). Plants were sprayed with 2, 4, 6, and 8 ppm sulfur 45 days after sowing (untreated plants were kept as control). Plants of the “Roma” cultivar receiving 6 ppm sulfur exhibited maximal shoot and root biomass values followed by those receiving 4 ppm under both temperature conditions. Maximal CO2 index, photosynthetic rate, transpiration rate, and greenness index values (188.1 µmol mol−1, 36.3 µmol CO2 m−2 s−1, 1.8 µmol H2O m−2 s−1, and 95 SPAD, respectively) were observed in plants of “Roma” cultivar grown at 25 °C, indicating positive influences of sulfur on tomato physiology. Similarly, sulfur maximized proline, nitrogen, phosphorus, and potassium contents in leaves of both genotypes at both temperatures. The differences between control and sulfur-treated plants grown under heat stress indicate a possible role of sulfur in mitigating heat stress. Overall, our results suggest that 6 ppm of sulfur is the best dose to alleviate tomato heat stress and enhance the morphological, physiological, and biochemical attributes of tomato plants.

Research on green technologies for immobilizing mercury in waste to minimize chemical footprint

This paper is devoted to the use of the principles of green chemistry in the search for technologies to reduce the chemical footprints of areas. The chemical footprint for mercury and its compounds was taken as an example to study. These chemicals belong to priority pollutants and their ever-increasing amounts in the environment have caused concern around the world, which is reflected in the adoption of the Minamata Convention. The Minamata Convention aims to protect human health and the environment from anthropogenic releases of mercury and mercury compounds. This Convention is an important component of efforts to achieve sustainable, inclusive and resilient human development through SDGs, which were adopted in September 2015 and especially SDG Goal 12: Ensure sustainable consumption and production patterns. Relevancy of this work is due to the need for the adopting of a series of measures to withdraw some mercury-containing goods from the production cycle. Also, one of the most important statements of the Convention is in reference to the issue of mercury contamination when recycling mercury. An important aspect of the work described in this paper is the reduction of mercury pollution from mercury-containing waste products by the development of technology in accordance with the principles of green chemistry. These are energy-efficient and without waste -water discharge technology. The main result of this work is the fundamental research for a transformation of elemental mercury and its compounds into less dangerous forms for the human body and the environment, providing a guaranteed absence of mercury-containing waste in the atmosphere and water systems. Various conditions for reaction of the immobilization of metallic mercury in mercury-containing wastes were investigated and it was established that it proceeded best under the following conditions: Reaction of metallic mercury with elementary sulfur;A ball mill is used as a reactor, which ensures constant updating of the contact area of the phases;For a good dispersion of mercury and for a relatively quick and complete reaction a large excess of sulfur up to 6500 % by stoichiometry (e.g. ratio of mercury:sulfur = 1:1.5 by weight) is necessary;The addition of a very small amount of water also has a positive effect (hydromodulus of Solid:Liquid = 3:1 by weight).

Biological Denitrification of Nitrate Contaminated Ground Water with Elementary Sulfur

Extensive utilization of synthetic fertilizer and release of improperly treated wastewater from industrial or municipal facilities are the causes of nitrate contamination in natural water systems. Nitrate is one of the main contributors to eutrophication of surface water bodies which can cause severe ecological and environmental problems. Consumption of nitrates can have several detrimental health effects. One adverse health effect is methemoglobinemia or “blue-baby" syndrome. Sulfur based biological denitrification process is autotrophic denitrification using Thiobacillus denitriflcans, in which process is conducted by denitrifying bacteria which require inorganic carbon for carbon source. These denitrifying bacteria oxidizes elemental sulfur to sulphate while reducing nitrate to nitrogen gas, thereby eliminating the need for addition of organic carbon compounds as energy sources to drive denitrification. This Study was conducted on biological denitrification with elemental sulfur packed small-scale bed columns and it was found to be maximum 39 percent efficiency of NO3-N removal at 1.5 hours HRT having bicarbonate range 153.72 to 207.40 mg/l and that of TIN removal was up to 35 percent removal efficiency. In this biological process, elemental sulfur is converted into sulfate, and this renders the method unsuitable for the treatment of ground water containing high levels of endogenous sulfate.

Fabrication of Ag2S/CdS Heterostructured Nanosheets via Self-Limited Cation Exchange

Highly crystalline vertically aligned Ag2S/CdS heterostructured nanosheets with lateral sizes of several micrometers and thicknesses of a few nanometers are prepared directly on silver surfaces by a two-step process. Firstly, Ag2S sheets were prepared by direct reaction of partially dissolved elementary sulfur in methanol with a solid silver surface in methanol at room temperature. The second step involves a self-limited cation exchange of Ag+ vs. Cd2+ to achieve the formation of large-area Ag2S/CdS heteronanosheets on the solid substrate. The cation exchange was proven and investigated over time via several analytical methods, e.g. X-ray diffraction, Raman spectroscopy and three-dimensional photoluminescence mapping.

MICROCIRCULATION OF THE SKIN IN WORKERS OF GAS-PROCESSING PLANT

Microcirculatory disorders play an important role in the pathogenesis of dermatoses, including those caused by the influence of adverse factors of production environment. 158 men from the Astrakhan gas processing plant (AGPS) aged from 28 to 59 years (40.23 ± 0.49 years) and 77 healthy volunteers, resident in the city of Astrakhan in age from 25 to 55 years (38,18 ± 0,99 years) were examined. Depending on the technological stage of processing of reservoir gas workers AGPS had contact with various harmful and dangerous factors, among which were the formation of gas, elementary sulfur, hydrocarbons, saturated and unsaturated aliphatic compound, nitrogen oxides, etc. In more than 90% of cases in the skin of workers AGPS serious violations of blood perfusion in small vessels, and in the surface areas more often than in the deep, while marked asymmetry of cutaneous microcirculation were revealed. Laser Doppler flowmetry can be recommended as a noninvasive method of monitoring the condition of microcirculation and early diagnosis of premorbid changes in the skin of workers of the gas processing plant exposed to adverse factors of production environment.

A Comparative CFD Simulation Study of Two-Channel and Three-Channel Claus Reactors

The Claus reactors is widely used to recover elementary sulfur from hydrogen sulfide that is contained in fresh natural gas. It involves thermal oxidation of hydrogen sulfide and its reaction with sulfur dioxide to form sulfur and water vapor. To improve the efficiency of the process, we built two kinds of 3-dimensional Claus reactor models to explore the key factors that affect the combustion reactions. The two-channel Claus reactor consisted of an air channel and an acid gas channel (60% H2S, 33% CO2, 7%H2O) while the three-channel Claus reactor consisted of two air channels and an acid gas channel (60% H2S, 33% CO2, 7%H2O). The two-channel model was built according to the devices used in the factory while the three-channel model was improved by us from the two-channel model. In both the two models, air and acid gas turned into swirling flow in their channels respectively before their mixture. Then air and acid gas mixed and burned at the throat of the models. The most remarkable difference between the two kinds of Claus reactors was that the three-channel reactor had an additional inner air channel inside the acid gas channel that can be helpful to the mix of the acid gas and air. The second difference was that the two kinds of reactors had different deflectors to swirl in the flow fields. In this study, we compared the flow fields and concentration fields of the two kinds of Claus reactors by using a computational fluid dynamics (CFD) tool. The simulation results indicated that the swirling intensity and the mix intensity played an important role in the combustion reactions. The efficiency of sulfur recovery in Claus reactors increased with an increase of the swirling intensity or the mix intensity. The stronger the swirling intensity or the mix intensity was, the sooner the mixture of air and acid gas reached to the best stoichiometric ratio. The three-channel reactor had a better performance than that of the two-channel reactor due to the additional inner air channel which can strengthen the mix of the acid gas and air from the inside of the acid gas. Moreover, the helix deflectors in the three-channel reactor had a better swirling performance than that of the vane deflectors in the two-channel reactor. From the comparison of the two models, we can obtain a way to improve the process of elementary sulfur recovery in the industry, which can be helpful to reduce pollution emissions and improve economic performance.

Nitrogen loss by volatilization of nitrogen fertilizers applied to coffee orchard

ABSTRACT Ammonia volatilization (N-NH3) is one of the main pathways of Nitrogen loss reducing nitrogen use efficiency in coffee orchard. This work aimed at quantifying ammonia volatilization (N-NH3) losses from N-sources to be used in coffee plantations fertilization in Brazil. The experiment was conducted in the field on a dystrophic red latosol (Ferralsol in FAO's classification) at the Coffee Research Sector, University of Lavras, MG, Brazil. The experimental design was of complete randomized blocks with three repetitions of the following treatments: conventional urea, ammonium nitrate and urea + 0.15% Cu and 0.4% B, urea + anionic polymers, urea + elementary sulfur (S0) + polymers, and urea + plastic resin. These N sources were split into three doses of 150 kg ha-1 and band applied. The N-NH3 losses by volatilization and variations of pH (H2O) were measured, before and after N application. The N-sources contributed to reduce the soil pH, measured after the third nitrogen fertilization. The N-NH3 losses by volatilization (average from three applications) was as follows: urea + anionic polymers (35.8%) > conventional urea (31.2%) = urea + S0 + polymers (31.0%) > urea + 0.15% Cu + 0.4 % B (25.6%) > urea + plastic resin (8.6%) = ammonium nitrate (1.0%).

Tribological Properties of Nanolamellar MoS2Doped with Copper Nanoparticles

This study aimed at examining the tribological properties of nanolamellar molybdenum disulfide doped with copper nanoparticles. Nanolamellar molybdenum disulfide was produced using self-propagating high-temperature synthesis via the reaction between elementary sulfur and nanosized molybdenum powder prepared by electrical explosion of wires. Copper nanoparticles were also prepared by electrical explosion of copper wires. Comparative tribological tests were carried out for nanolamellar and commercial molybdenum disulfides doped with 7 wt.% of copper nanoparticles. It was demonstrated that doping copper nanoparticles additives reduce wear of the friction body when using both commercial and nanolamellar molybdenum disulfide.