Identification of mineral associations in skarn-rare-metallic deposits in Western Uzbekistan

This article solves the applied scientific problem of identifying mineral carriers and mineral associations of platinum mineralization in the skarn-gold-rare metal Koytash and Lyangar deposits. One of the applied research tasks was to identify the forms of mineral carriers and mineral associations of platinum-metal mineralization for these deposits. We carried out geological fieldwork of the Koytash and Lyangar deposits, which included a sampling of sulphide-rare metal and silver-polymetallic ores, and conducted laboratory studies by using mass spectrometry, atomic absorption, electron microprobe, and other modern methods. This article addresses the complex formation of sulphide-rare-metal and silver-polymetallic ores of the above-mentioned deposits. The formation of mineral associations bearing rare-metal (W-Mo) mineralization that formed in the early alkaline stage, in almost all sites, is completed by sulphide-rare metal and silver-polymetallic mineralization that often carry industrial-grade concentrations of noble and other metals. We have identified a recommended location for the concomitant extraction of useful components, the mineral composition, and the impure elements in them. These data show the prospects of sulphide-rare metals and sulphidepoly-metallic ores in the Koytash deposit for precious metals, bismuth, etc

PHOTOLUMINESCENCE AND RAMAN SPECTRA OF DIAMOND MICROPOWDERS PLACED IN PHOTON TRAPS

The photoluminescence and Raman spectra of diamond micropowders placed in photon traps under repetitively pulsed excitation by a copper vapor laser are studied. The recorded spectra of the photoluminescence and Raman spectra of micro-diamond powders were characterized by anomalously high intensity, which was associated with the trapping of exciting radiation in microparticles, the size of which significantly exceeded the lasing wavelength

PHOTOLUMINESCENCE AND RAMAN SPECTRA OF DIAMOND MICROPOWDERS PLACED IN PHOTON TRAPS

The photoluminescence and Raman spectra of diamond micropowders placed in photon traps under repetitively pulsed excitation by a copper vapor laser are studied. The recorded spectra of the photoluminescence and Raman spectra of micro-diamond powders were characterized by anomalously high intensity, which was associated with the trapping of exciting radiation in microparticles, the size of which significantly exceeded the lasing wavelengt

A Farm in Kumsangir of Tajikistan: A Perspective of Water/land Use along Pyandzh River

We carried out an assessment of natural resources use and management along with the on-farm observations and experience gathered through a fieldwork expedition along the riparian basin of Pyandzh River from Tajik side. It is described the natural vegetation irrigation history, technologies, agriculture, crops diversity and farmer development system through this vast area of Khatlon Province of Southwestern Tajikistan. Target area is Kumsangir District and Mumin Farm in the district along Pyandzh River. By performing this survey, we could further examine our preliminary studies on the potentials for agriculture using of Subsurface Drip Irrigation (SDI) technique on the right bank of Pyandzh River. Many of the local farmers, pastoralist communities, and some of the agricultural authorities and governmental leaders were interviewed to help understand the history of their irrigation infrastructures, their concerns on the issue of land use and agricultural activities, and their outlook and desires to implement cost-effective watershed-scale water saving technologies

A seasonal forecasting procedure for reservoir inflows in Central Asia

This study develops a procedure for seasonal forecasting river discharge from headwaters above strategically important hydropower plants in Kyrgyzstan and Tajikistan. The El Niño Southern Oscillation, North Atlantic Oscillation, and Indian Ocean Dipole indices were used as inputs. Predictability was evaluated for average summer inflows conditional on the tercile of the preceding winter climate mode. We find that the winter Niño 3.4 index was significantly positively correlated with following summer inflows to Nurek, Andijan, and Toktogul reservoirs during the period 1941–1980. Kruskal–Wallis and Kolmogorov–Smirnov tests show significant differences in the distributions of summer inflows depending on previous winter Niño 3.4 for all three reservoirs. At Nurek, summer inflows were on average 19% greater following a winter El Niño. During 1941–2016, mean summer inflows to Nurek reservoir linked to previous November–December Niño 3.4 achieved a Heidke Hit Proportion of 51–59% (compared with 33% expected by chance). Acceptable predictions of summer inflow volume were made 44% of the time. Higher inflows are explained by a south‐ westerly moisture flux that brings above average precipitation to Central Asia during winter El Niño conditions. Our procedure requires limited data, technical or computing resources—all considerations in data sparse, low capacity regions. Given planned developments of other large, headwater impoundments in Central Asia, early outlooks of discharge could contribute to improved dam safety, economic performance, and transboundary water sharing around such projects

Organic Cation Substitution in Hybrid Perovskite CH₃NH₃PbI₃ with Hydroxylammonium (NH₃OH⁺): A First-Principles Study

The exceptional success of hybrid perovskite materials in the next generation of photovoltaics has attracted the interest of scientists across many fields in photophysics. Structural and optoelectronic properties are of main importance when searching for potential compounds beyond photovoltaics or as top-cell absorbers. In this article, we theoretically study the thermodynamic stability and electronic properties of organic cation substituted MAPbI₃ with hydroxylammonium ions. Results from structural relaxations are compared to predictions from Goldschmidt tolerance factors. Our findings evidence that size effects and the initial orientation of the central cation result in strongly alternated octahedral distortions and markedly different optoelectronic properties. The latter becomes noticeable mainly due to band gap variations and significant frontier orbital splitting, which is observed in the case of relativistic calculations and seems to highly depend on the inorganic network deformation