Modelling of the lactation curve of grazing Mongolian mare

Current research was performed to determine the yield and composition of milk during entire lactation period, which lasts June to February of following year and describe fit of lactation curve using different mathematical models. Total 8 mares, aged from 5 to 12 years were used in the study. The total milk yield, calculated by Fleischmann's method, as well as the models were various and shape of curves for Linear, Quadratic, Cubic, and Quartic equations, and Wood's curve were different. The determination index (R2) of the milk yield and composition curve models ranged from 0.474-0.987, and R2 of Quartic curve model for milk yield (0.987) was the highest. Study result showed that the above models were able to describe the lactation curve of the milk yield and composition, and the Quartic model best fit to data collected from Mongolian mare and allowed a suitable description of the shape and dynamics of curve. Бэлчээрийн маллагаатай Монгол гүүний лактацын муруйн загварчлал Монгол гүүний саалийн нийт хугацаанд буюу VI сараас дараа жилийн III сар хүртэл саамны гарц, найрлагын хэмжээг үндэслэн математик загваруудаар лактацын муруй байгуулах, монгол гүүний лактацын муруйд хамгийн нийцэл сайтай загварыг сонгон тодорхойлох зорилгоор энэхүү ажлыг хийж гүйцэтгэлээ. Судалгаанд 5-12 насны 8 гүүг ашиглав. Сүүний нийт гарц, найрлагын хэмжээг Вүүд (Wood’s)-ын загвар болон шугаман, шугаман бус регрессын тэгшитгэлээр загварчлахад лактацын муруйн загварууд харилцан адилгүй байв. Саамны гарц, найрлагын муруйн загваруудын детерминацийн индекс (R2) нь 0.474-0.987-ийн хооронд хэлбэлзэж, биквадрат загварын хувьд хамгийн нийцэл өндөр буюу 0.987 байв. Судалгааны үр дүнд дээрх аргуудаар саамны гарц, найрлагын лактацын муруйг загварчлах боломжтой нь харагдаж байсан ба эдгээрээс биквадрат тэгшитгэлийн загвар нь бэлчээрийн маллагаатай монгол гүүний саамны өгөгдөлтэй хамгийн сайн нийцэж, лактацын муруйн хэлбэр, хөдлөлзүйн хувьд тохирч байв. Түлхүүр үг: саамны гарц, саамны найрлага, лактацын муруй

Using molecular dynamics to unravel phase composition behavior of nano-size pores in frozen soils: Does Young–Laplace equation apply in low temperature range?

The phase composition curve of frozen soils is a fundamental relationship in understanding permafrost and seasonally frozen soils. However, due to the complex interplay between adsorption and capillarity, a clear physically based understanding of the phase composition curve in the low temperature range, i.e., <265 K, is still absent. Especially, it is unclear whether the Young–Laplace equation corresponding to capillarity still holds in nano-size pores where adsorption could dominate. In this paper, a framework based on molecular dynamics was developed to investigate the phase transition behavior of water confined in nano-size pores. A series of simulations was conducted to unravel the effects of the pore size and wettability on the freezing and melting of pore water. This is the first time that the phase composition behavior of frozen soils is analyzed using molecular dynamics. It is found that the Young–Laplace equation may not apply in the low temperature range.

First principles studies of silicon as a negative electrode material for lithium-ion batteries

An investigation of Li–Si alloys using density functional theory is presented. Various calculation methods and pseudopotentials are analyzed to best reproduce the potential versus composition curve of a Li/LixSi electrochemical cell at high temperature using the experimentally observed Li–Si phases. Total energy calculations, structural optimizations, and bulk modulus estimations were completed for the Si, Li12Si7, Li7Si3, Li13Si4, Li15Si4, Li22Si5, and Li phases. The potential plateaus of the co-existing phase regions, obtained using the projector augmented wave (PAW) method, have an average absolute error of 31 mV with respect to experiment. The Li7Si3 and Li15Si4 compositions are discussed and the Li15Si4 phase is found to have a lower bulk modulus relative to the other phases.

Electrochemical Charge for the Formation of Metal Hydrides from LiH+M (M=Mg, Al)

For a formation of metal hydride of MgH2 or AlH3 under room temperature and ambient pressure, the cathode electrodes of metal and lithium hydride are electrochemically charged with Li anode electrodes in the system of Li-ion extraction. For MgH2 formation, the VC (Voltage-Composition) curve of Mg + 2LiH during charge shows a plateau voltage at 0.6 V until the final composition of 1.05 Li extraction. After charge MgH2 phase is observed by the XRD measurement. Therefore MgH2 is produced by the electrochemical charge from Mg and LiH. For AlH3 formation, Al + 3LiH is charged until the final composition of 0.6 Li at a plateau voltage of 0.8 V which corresponds to the reaction between Al and LiH for the formation of AlH3. In the XRD profile after charge AlH3 phase is not detected although the intensities of Al and LiH decrease compared with these before charge, which suggests the reaction leading to the formation of AlH3.

Some Physicochemical Studies on Organic Eutectics and Molecular Complex: Urea – p-nitrophenol System

The phase diagram of urea–p-nitrophenol system, in the form of a temperature-composition curve, shows the formation of a 1: 1 molecular complex surrounded by two eutectics containing 0.216 and 0.777 mole fraction of p-nitrophenol. Data on growth velocity (v), obtained by measuring the rate of movement of the interface at different undercoolings (ΔT), suggest that they obey the Hillig–Turnbull equation, i.e., v = u (ΔT)n, where u and n are constants depending on the nature of materials involved. From the heat of fusion values, determined by the differential scanning calorimetry (DSC) method, heat of mixing, entropy of fusion, roughness parameter, interfacial energy, radius of the critical nucleus, and the excess thermodynamic functions were calculated. While the x-ray diffraction data show that the eutectics are not mechanical mixtures of the components under investigation, the microstructural investigations give their characteristic features.

Heat-of-mixing for the partially miscible system N2/C2H6

Heats-of-mixing for the liquid system nitrogen/ethane have been measured at 92.3 K and 0.6309 MPa using a cryogenic flow calorimeter. The heat-of-mixing versus composition curve shows that the system is only partially miscible; the compositions between which liquid–liquid separation occurs have been estimated.