Vapor Liquid Research Articles

Molecular modeling and simulation of organic electrolyte solutions for lithium ion batteries.

Multi-criteria optimization is used for developing molecular models for ethylene carbonate (EC) and propylene carbonate (PC), organic solvents commonly used in Li-ion batteries. The molecular geometry and partial charges of the solvents are obtained from quantum mechanical calculations. Using a novel optimization strategy that combines systematic variations of the Lennard-Jones parameters with a reduced units approach, the models are fitted to experimental data on the liquid density, vapor pressure, relative permittivity, and self-diffusion coefficient. Since no experimental data for the self-diffusion coefficient of pure EC were available in the literature, they are measured in this work using a gradient-based nuclear magnetic resonance technique. For all pure component properties, excellent agreement between experiment and simulation is obtained. Moreover, the predictive capabilities of the new solvent models are assessed by comparison to experimental data for the liquid density and relative permittivity of mixtures of EC and PC. In addition, molecular models for the anions PF6-, BF4-, and ClO4- in solutions of their lithium electrolytes in PC are developed using experimental data on the solution densities. Finally, the self-diffusion coefficients of LiPF6 in PC and in aqueous solution are predicted and compared, showing that diffusion is much slower in the organic solution due to the formation of larger solvent shells around the ions. Furthermore, an analysis of the radial distribution functions in these solutions suggests that the ions have much less impact on the structure of the solvent PC than on water.

Numerical Modeling of Water Transport in a Microporous Layer-Coated Porous Transport Layer for a Polymer Electrolyte Membrane Water Electrolyzer with an Interdigitated Flow Field for Internal Gas-Liquid Separation

A novel design for interdigitated flow fields in polymer electrolyte membrane electrolyzers has been developed for both ground and space applications. This design separates oxygen and liquid water internally, eliminating the need for water circulators to remove bubbles and external gas-liquid separators with buoyancy. The capillary pressure in the hydrophobic microporous layer (MPL) of the anode porous transport layer facilitates internal separation of oxygen gas and pressurized liquid water. A finite element model (COMSOL Multiphysics) simulates water transport in the MPL, while electrochemical impedance spectra determine the electrochemical kinetic parameters for the model. The model takes into account the oxygen bubble coverage of the cathode, liquid water saturation in the MPL, and the current ratio between liquid water and water vapor at the MPL-cathode layer interface. The vapor from liquid water in the MPL is modeled to mix with oxygen for diffusion. A volumetric water evaporation rate as a linear function of liquid water saturation in the MPL is assumed, where the rate constant is estimated from vapor permeation tests.

Numerical Modeling of Water Transport in a Microporous Layer-Coated Porous Transport Layer for a Polymer Electrolyte Membrane Water Electrolyzer with an Interdigitated Flow Field for Internal Gas-Liquid Separation

A novel design for interdigitated flow fields in polymer electrolyte membrane electrolyzers has been developed for both ground and space applications. This design separates oxygen and liquid water internally, eliminating the need for water circulators to remove bubbles and external gas-liquid separators with buoyancy. The capillary pressure in the hydrophobic microporous layer (MPL) of the anode porous transport layer facilitates internal separation of oxygen gas and pressurized liquid water. A finite element model (COMSOL Multiphysics) simulates water transport in the MPL, while electrochemical impedance spectra determine the electrochemical kinetic parameters for the model. The model takes into account the oxygen bubble coverage of the cathode, liquid water saturation in the MPL, and the current ratio between liquid water and water vapor at the MPL-cathode layer interface. The vapor from liquid water in the MPL is modeled to mix with oxygen for diffusion. A volumetric water evaporation rate as a linear function of liquid water saturation in the MPL is assumed, where the rate constant is estimated from vapor permeation tests.

Impedance Spectroscopy Study of Charge Transfer in the Bulk and Across the Interface in Networked SnO2/Ga2O3 Core–Shell Nanobelts in Ambient Air

Metal oxide core–shell fibrous nanostructures are promising gas-sensitive materials for the detection of a wide variety of both reducing and oxidizing gases. In these structures, two dissimilar materials with different work functions are brought into contact to form a coaxial heterojunction. The influence of the shell material on the transportation of the electric charge carriers along these structures is still not very well understood. This is due to homo-, hetero- and metal/semiconductor junctions, which make it difficult to investigate the electric charge transfer using direct current methods. However, in order to improve the gas-sensing properties of these complex structures, it is necessary to first establish a good understanding of the electric charge transfer in ambient air. In this article, we present an impedance spectroscopy study of networked SnO2/Ga2O3 core–shell nanobelts in ambient air. Tin dioxide nanobelts were grown directly on interdigitated gold electrodes, using the thermal sublimation method, via the vapor–liquid–solid (VLS) mechanism. Two forms of a gallium oxide shell of varying thickness were prepared via halide vapor-phase epitaxy (HVPE), and the impedance spectra were measured at 189–768 °C. The bulk resistance of the core–shell nanobelts was found to be reduced due to the formation of an electron accumulation layer in the SnO2 core. At temperatures above 530 °C, the thermal reduction of SnO2 and the associated decrease in its work function caused electrons to flow from the accumulation layer into the Ga2O3 shell, which resulted in an increase in bulk resistance. The junction resistance of said core–shell nanostructures was comparable to that of SnO2 nanobelts, as both structures are likely connected through existing SnO2/SnO2 homojunctions comprising thin amorphous layers.

Extractive distillation using salt-based deep eutectic solvent as entrainer for separating acetonitrile-water mixture

Salt-based deep eutectic solvents (DESs) have been proposed in this work for the separation of the azeotrope of acetonitrile and water (H2O). The vapor–liquid equilibrium experiments indicated that (ChCl:U:CaCl2)1:2:0.36 exhibits an higher selectivity among all of the entrainers investigated and eliminates the azeotropic point of acetonitrile and water mixture. Moreover, the calculated values by NRTL model coincide well with the experimental data for the systems (acetonitrile + H2O + (ChCl:U:CaCl2)1:2:0.36). Based on the thermodynamic study, the conceptual process design was established to evaluate the competitiveness of the suggested entrainers for the separation of acetonitrile and water. It was determined that the thermodynamic efficiency (η) in the extractive distillation (ED) process utilizing the new salt-based DESs entrainers increases 60.31 % compared with the benchmark entrainer ethylene glycol (EG). Conversely, the ED process using (ChCl:U:CaCl2)1:2:0.36) entrainer can reduce the total annual cost (TAC) by about 7.81 % and the CO2 emissions (ECO2) by 14.74 %. The ED process using (ChCl:U:CaCl2)1:2:0.36) as entrainer shows the high energy efficiency, low economy cost and low CO2 emissions with a great industrial application prospect when compared to the bench marked process.

Numerical modelling of autogenous shrinkage of rice husk ash blended cement mortar

Addition of rice husk ash (RHA) is an effective internal curing method to mitigate self-desiccation and autogenous shrinkage of hydrating cementitious materials. Although a certain number of experimental researches on this topic have been carried out, a comprehensive study about numerical simulation of mitigating effect of RHA on autogenous shrinkage of cementitious materials is still scarce. In this study, a numerical model of autogenous shrinkage of rice husk ash blended cement mortar was proposed. The proposed numerical model was based on Pickett model and improved by taking visco-elastic behaviour of rice husk ash blended cementitious materials into account. Final setting time, chemically bound water, compressive strength, internal relative humidity (RH) and autogenous shrinkage of pure Portland cementitious materials and rice husk ash blended cementitious materials were experimentally studied. Liquid absorption capacity and water vapour desorption isotherm of rice husk ash were also measured. The comparison between the simulated and measured autogenous shrinkage showed that the autogenous shrinkage of rice husk ash blended cement mortar can be predicted accurately with the proposed numerical model.

Investigation on Saturation Vapor Pressure of NH3–H2O–LiBr in Absorption Energy Storage System

Energy storage technology applied between building energy and renewable energy exhibits inherent characteristics of continuity, stability, and high efficiency of energy density. To improve the energy storage density and efficiency of solution absorption energy storage system, an innovative method is proposed by adding ammonia to regulate the saturated vapor pressure of Lithium Bromide solution, which is used as the energy storage working fluid for the absorption energy storage system. Based on the static method principle of vapor–liquid equilibrium of multiple working fluids, a testing platform for the vapor pressure of multiple working fluids was built. The pressure of the Lithium Bromide solution and the Lithium Bromide solution added Ammonia with a concentration of 58% were measured. The results show that the pressure of the Lithium Bromide solution added Ammonia is 2–5 times higher than that of the Lithium Bromide solution. The maximum relative deviations between the calculated value of the models fitted by Antoine equation and Peng Robinson state equation and the experimental value are 4.65% and 10.88%, respectively. That indicates that the model fitted by Antoine equation is more precise for the calculation of the equilibrium pressure of the ternary working fluid. The equilibrium pressure of the Lithium Bromide solution added Ammonia is predicted by the model fitted by the Antoine equation.

On the Multi-Layered Adsorption of Alcanols in the Vicinity of Liquid–Vapor Transition at the Saturated Hydrocarbon–Water Interface

Structure of adsorption layer of long-chain monoatomic alcohols: 1-dodecanol and 1-tetracosanol at the interfaces n-hexane – water and n-hexadecane – water in the vicinity of “liquid – vapor” thermotropic phase transition is investigated by the method of X-ray reflectometry at synchrotron source. Model-independent structural data obtained on the adsorption layers under investigation deviate considerably from the structural parameters which have been proposed previously within a model-based representation and discussed in previous publications on said systems. It is shown that in the low-temperature mesophase the adsorption film consists of a Gibbs monolayer, a transitional liquid region with thickness of two to three monolayers ~50 Å and an extended (wide up to 200 Å) layer of micelles. Presence of a plane of the closest approach of micellar layer to the adsorption film at the interface is established. Transition to the high-temperature mesophase is followed by liquefying and partial evaporation of alcanol film along with observed depletion of micellar layer down to its complete disappearance.

Numerical analysis of multistage ultrasonic atomization enhanced ammonia-water falling film absorption

The absorption refrigeration system is a widely used system that utilizes waste heat and is environmentally friendly. However, many current systems still suffer from challenges such as large volume, and high initial investment. Meanwhile, optimizing the absorber is crucial for enhancing system performance as it is one of the main components. In this study, a novel absorber model is proposed and its influencing factors of performance are comprehensively analyzed. In this model, the traditional falling film absorber is divided into multiple stages, with an ultrasonic atomizer (UA) installed in each stage to enhance absorption. In each stage, falling film and atomization absorption occur simultaneously, and their outputs are combined and weighted at the exit to maintain continuous droplet absorption, effectively utilizing the entire absorber volume. In this process, the vapor–liquid contact area is increased through atomization, and simultaneously, generated heat is removed by the cooling water during mixing. As a result, the absorber’s absorption capacity increases, and the outlet solution temperature decreases. The results demonstrate that compared to the traditional falling film absorber, the proposed absorber, when divided into two stages with a droplet diameter of 50 μm and an atomization rate x = 0.7, shows a 60.64 % increase in ammonia absorbed rate. Additionally, compared to double-stage absorber, triple-stage absorber increases the ammonia absorption by 9.52 %. As the number of stages increased, the strengthening effect persisted, albeit with a gradually diminishing rate of increase. Scaling up to ten stages results in a 152.63 % absorption rate increase and a size optimization of 60.43 %. In this paper, multi-stage ultrasonic atomization is innovatively introduced into the falling film absorber, which enhances ammonia absorption and reduces the volume of the absorber. Additionally, the multi-stage atomization offers an innovative method to improve the droplet absorption process.

TAMie Force Field for Alkanethiols: Multifidelity Gaussian Processes for Dealing with Scarce Experimental Data.

This study extends the transferable anisotropic Mie potential (TAMie) to alkanethiols. The force field parameters are optimized by using an analytic equation of state as a surrogate model. Given the lack of experimental density data at elevated temperatures where Monte Carlo simulations have high statistical precision, the equation of state is supplemented by a linear multifidelity Gaussian process approach to bridge the temperature gap. Force field parameters are adjusted by minimizing squared deviations of calculated vapor pressures and liquid densities from experimental data of 1-propanethiol, 1-butanethiol and 1-pentanethiol leading to small mean absolute relative deviations in liquid densities and vapor pressures. The force field is transferable to higher 1-thiols, as shown for 1-hexanethiol and 1-octanethiol. Individual parameter sets are provided for methanethiol and ethanethiol. The shear viscosity of pure substances is predicted in fair agreement with experimental data, considering that it is not included in the parametrization. Further, the phase behavior of binary mixtures of alkanethiols with alkanes is studied, and predictions of the TAMie model are found in excellent agreement with experimental data.

Modeling the thermodynamic properties of cyclic alcohols with the SAFT-γ Mie approach: application to cyclohexanol and menthol systems

Cyclic alcohols are commonly found in natural and synthetic products and are involved in many biological processes. An ability to model their thermodynamic properties is of interest in food, flavouring, and pharmaceutical manufacturing, particularly for mixtures for which available experimental data are limited. Good examples are mixtures including menthol, a naturally occurring cyclic alcohol widely used in the food and pharmaceutical industries, well-known for its cooling-sensation properties and its role in the discovery of the TRPM8 receptor. Here, we extend the SAFT-γ Mie group-contribution method to model cyclic alcohols, by introducing a new cCHOH group (c for cyclic) composed of two identical Mie segments. Three association sites (two electronic sites of type e and one hydrogen site of type H) are also included to mediate hydrogen bonding. New parameters that characterise the group interactions (one new like interaction and 26 new unlike interactions) are developed and are employed to determine the thermophysical properties (vapour pressure, saturation density, vaporisation enthalpy, and second-order thermodynamic derivative properties) of pure cyclic alcohols, and mixture properties (vapour–liquid equilibria, liquid–liquid equilibria, solid–liquid equilibria, density, and excess enthalpy) of cyclic alcohols in several solvents. The quality of the model is evaluated by comparing predictive calculations with experimental data of 76 systems: six pure fluids and 70 binary mixtures, selected from a large range of solvent families: cyclic, linear, and branched alkanes, 1-alcohols, 2-alcohols, 2-ketones, esters, aromatic compounds, water, and carbon dioxide. Very good overall agreement is found, including for the prediction of solid–liquid solubility, which confirms the transferability of the new group parameters. Together with previously developed parameters, these open the way for the prediction of the thermodynamic properties of further complex mixtures.

Thermo-hydrodynamic characterization and mapping of the two-phase flow in a capillary tube

The study presents an experimental investigation on the behavior of condensate film and liquid–vapor meniscus in the unit cell of a pulsating heat pipe (PHP) at different operating boundary conditions, and their respective roles in determining PHP’s performance. The orientation and the temperatures of evaporator and condenser sections are taken as the variable operating boundary conditions whereas the amplitude of oscillations influences the performance of the PHP. The entire thermo-hydrodynamic phenomenon is captured using high-speed imaging. By tracking the interface of liquid film and vapor, different regimes for film flow in the condenser section are observed and characterized. Also, the oscillation amplitude has been quantified at different operating boundary conditions. Despite a quite small tube diameter, gravity plays a key role in determining the liquid and vapor phase distributions in the tube. The variation of oscillation amplitude is intimately linked with the nuances of film flow regimes and inter-regime transitions. The optimum inclination angle, and evaporator and condenser temperatures are found to exist for the PHP unit cell which maximize the oscillation amplitude. The dependence of optimum inclination angle on condenser temperature has also been understood along with. Further, the associated film flow regime in condenser which facilitates these optima has also been recognized. All variable operating boundary conditions are observed to have a peculiarly mixed influence on the flow regimes and thus oscillation amplitude. The study would help to achieve a better elementary understanding of the role of condensate film flow in determining PHP’s performance and develop a flow regime map particularly for PHPs.

Phase behavior of the carbon dioxide/toluene/poly(ethylene glycol) ternary system

The phase behavior of a carbon dioxide (CO2)/toluene (Tol)/poly(ethylene glycol) (PEG) ternary system was investigated in this study to consider the effect of the polymer species on the phase diagram. Measurements were performed using a synthetic method combined with laser displacement and turbidity measurements. Bubble points (vapor–liquid phase separation) were determined from changes in the piston displacement and cloud points (liquid–liquid (LL) phase separation) were determined from changes in the turbidity. The phase boundaries of the CO2 mass fractions ranging from 0.113 to 0.496 were measured by varying the Tol/PEG mass ratio. The homogeneous phase area decreased when the mass ratio of PEG to Tol increased and/or the temperature decreased. These changes in the LL phase-separation behavior were explained by referring to the free volume fraction and solubility parameter estimated using the Sanchez–Lacombe equation of state. The free volume integral fraction could explain the phase diagram, but not the solubility parameter; the effect of polymer species on the Px phase diagram of the ternary system was explained by considering specific interactions between dissimilar components. These results could promote a comprehensive understanding of the phase diagram of CO2/organic solvent/polymer systems and aid the prediction of phase behavior.

Comparison of methods for calculating the enthalpy of vaporization of binary azeotropic mixtures

Objectives. To calculate the molar enthalpy of vaporization of binary homogeneous mixtures based on isothermal and isobaric vapor–liquid equilibrium data, and to compare the results of calculation of molar enthalpy of vaporization by different methods with experimental data.Methods. Simulation of the vapor–liquid equilibrium of binary systems according to the Non-Random Two Liquid “local compositions” equation and thermodynamic calculations of molar vaporization enthalpies of binary mixtures at different conditions of vapor–liquid equilibrium were used.Results. Arrays of calculated data were obtained with regard to molar enthalpies of vaporization for 25 compositions of binary azeotropes (isothermal, isobaric conditions of phase equilibrium), and the full range of compositions of the benzene–ethanol system at atmospheric pressure.Conclusions. The accuracy of thermodynamic methods for calculating the vaporization enthalpy of binary azeotropic mixtures according to vapor–liquid equilibrium data is higher in 85% of cases for isothermal, and in 75% of cases for isobaric conditions. By taking into account the influence of temperature on the activity coefficients of components in the liquid phase, the values of excess molar enthalpy both for azeotrope compositions and for the full concentration range of the benzene–ethanol system under isobaric conditions of liquid–vapor phase equilibrium can be accurately reproduced.

Biomimetic bilayer phase change hydrogels with enhanced water adsorption and desorption for evaporative cooling

Hygroscopic hydrogels, reliable carriers for water-based evaporative materials, undergo shrinkage after evaporative cooling, and the consequent reduction in hygroscopic sites can significantly impair their recyclability in cooling period. To realize cyclic evaporative cooling for rapid regeneration and evaporation, bilayer phase change hydrogel (BPH) concept combining an upper layer of hygroscopic polymer film (CaCl2@ carboxymethyl cellulose/konjac glucomannan films, CaCl2@CMC/KGM, MAF) with a lower layer of hygroscopic hydrogel (CaCl2@poly(vinyl alcohol)/sodium tetraborate decahydrate hydrogel, CaCl2@PVA/Borax, PCH), is presented in this paper. The high liquid–vapor phase change enthalpy of BPH (1274 J/g) enables it to continuously and rapidly remove heat. Benefiting from the MAF hygroscopic porous skeleton, the saturated BPH exhibited a faster water evaporation rate (2.15 kg m−2 h−1) and comparable water vapor transmission rate (1.61 kg m−2 h−1) at 50 °C. After being heated at 50 °C for 1 h, BPH requires 9h to regain its initial mass at 25 °C, 90 % RH. Fifteen moisture adsorption–desorption cycles demonstrate the excellent cyclic regeneration capability of BPH. COMSOL Multiphysics simulation results indicate that evaporative cooling in BPH provides excellent heat dissipation (reduced by about 27 °C). BPH reduces the peak temperatures of a mobile phone by 7.8 °C while charging and 6.5 °C while gaming. This design will contribute to the future cooling of heat-related devices and global sustainability.

Molecular kinetic modelling of non-equilibrium evaporative flows

Recent years have seen the emergence of new technologies that exploit nanoscale evaporation, ranging from nanoporous membranes for distillation to evaporative cooling in electronics. Despite the increasing depth of fundamental knowledge, there is still a lack of simulation tools capable of capturing the underlying non-equilibrium liquid–vapour phase changes that are critical to these and other such technologies. This work presents a molecular kinetic theory model capable of describing the entire flow field, i.e. the liquid and vapour phases and their interface, while striking a balance between accuracy and computational efficiency. In particular, unlike previous kinetic models based on the isothermal assumption, the proposed model can capture the temperature variations that occur during the evaporation process, yet does not require the computational resources of more complicated mean-field kinetic approaches. We assess the present kinetic model in three test cases: liquid–vapour equilibrium, evaporation into near-vacuum condition, and evaporation into vapour. The results agree well with benchmark solutions, while reducing the simulation time by almost two orders of magnitude on average in the cases studied. The results therefore suggest that this work is a stepping stone towards the development of an accurate and efficient computational approach to optimising the next generation of nanotechnologies based on nanoscale evaporation.

Modeling Dipolar Molecules with PCP-SAFT: A Vector Group-Contribution Method.

Predicting thermodynamic equilibrium properties is essential to develop chemical and energy conversion processes in the absence of experimental data. For the modeling of thermodynamic properties, statistical associating fluid theory (SAFT)-based equations of state, such as perturbed-chain polar (PCP)-SAFT, have been proven powerful and found broad application. The PCP-SAFT parameters can be predicted by group-contribution (GC) methods. However, their application to the dipole term is substantially limited: current GC methods neglect the dipole term or only allow for a single dipolar group per substance to avoid handling the molecular dipole moment's symmetry effects. Still, substances with multiple dipolar groups are highly relevant, and their description substantially improves by including the dipole term in SAFT models. To overcome these limitations, this work proposes a vector-addition-based (Vector-)GC method for the dipole term of PCP-SAFT that accounts for molecular symmetry. The Vector-GC employs information on the substance's molecular 3D structure to predict the molecular dipole moment through a vector addition of bond contributions. Combining the proposed sum rule for dipole moments with established sum rules for the remaining parameters yields a consistent GC method for PCP-SAFT for dipolar substances. The prediction capabilities of the Vector-GC method are analyzed against experimental data for two substance classes: nonassociating oxygenated and halogenated substances. We demonstrate that the Vector-GC method improves vapor pressure and liquid density predictions compared to neglecting the dipole term. Moreover, we show that the Vector-GC method enables differentiation between cis- and trans-isomers. The Vector-GC method, hence, substantially increases the predictive capabilities and applicability domain of GC methods. All parameters are provided as JSON and CSV files, and the Vector-GC method is available through an open-source python package. Additionally, the developed regression framework for GC methods for PCP-SAFT is openly available. The regression framework can be employed to regress the Vector-GC method to other substance classes and is easily adaptable to other sum rules for PCP-SAFT.

Slip velocity and field information of two-phase cavitating flows

In this work, laser-induced florescent particle image velocimetry was performed to measure simultaneously the liquid and vapor velocity fields at the mid-span of a small-scale Venturi type section to determine the presence of a slip velocity between the phases. Various dynamic behavior and Kelvin–Helmholtz (K-H) instability involved in the cloud cavity shedding regime are discussed at four different cavitation numbers. The velocity, vorticity, and turbulence field information of the two phases are analyzed. The liquid–vapor mixture in a cavitating flow is usually considered a homogeneous medium in currently used computational models, but it is shown in this study that the two phases have very different dynamics. The measurements of the time-averaged velocities highlight the existence of a noteworthy slippage between the liquid and the vapor phases, especially in the upstream part of the cavitation region, where the slippage between the two phases can reach about 50% of the liquid velocity. Using phase-locked average, it is shown that the slip velocity in the upstream region is mainly located at the upper liquid–vapor interface, while the slip velocity in the closure area is near the bottom wall, due to the reentrant jet. These results contradict a primary assumption of the current models, where the medium is usually considered as a homogeneous mixture with a unique velocity field, thus providing a reference for future computational model improvement.

Immunofluorescence and biochemical investigation of the protective effects of naringin and diosmin on the freezability of Merino ram semen

BACKGROUND: Various antioxidant substances are added to sperm extenders to protect spermatozoa against oxidative stress and cryodamage. OBJECTIVE: To investigate the effects of the flavonoid diosmin (DIO) and a flavanone glycoside naringin (NAR) on the freezability of ram semen. MATERIALS AND METHODS: In this study, six Merino rams were used during the breeding season. The ejaculates were pooled after collection from the rams. Pooled ejaculates were divided into six groups: control, NAR 1 mM, NAR 2 mM, NAR 4 mM, DIO 2 mM, and DIO 4 mM, and then diluted with a TRIS-based diluent. The pooled semen was equilibrated, placed in 0.25 mL pipettes with 10 × 107 sperm cells in each pipette, and frozen in liquid nitrogen vapor. After 24 h, the pipettes were thawed at 37°C for 25 s and analyzed in terms of spermatological parameters. RESULTS: The highest plasma membrane integrity ratio was found in the DIO 4 mM group, whereas a statistically significant difference was found between the NAR 1 mM and NAR 2 mM groups (p<0.05). While the DIO 4 mM group had the highest acrosome integrity rate, a statistically significant difference was found between the other groups (p<0.05). Mitochondrial activity was the highest in the NAR 4 mM, DIO 4 mM and DIO 2 mM groups (p<0.05). In the analysis of the sperm membrane lipid profile, it was observed that the DIO group had the highest lipid-phospholipid ratio. In sperm membrane protein profile analysis, it was found that both additives exerted protective effects at different levels. The highest total protein content was seen in the DIO 4 mM and NAR 4 mM groups. 8-hydroxydeoxyguanosine (8-OhDG) positivity was more common in the control group than in the DIO and NAR groups. Cu-Zn superoxide dismutase (SOD) expression was lower in the control group and more intense in all other groups. Positive results were especially observed in the acrosome of the sperm cells. CONCLUSION: The addition of NAR and DIO to the ram semen extender increased the quality of sperm parameters after the freeze-thaw process.

Effect of different concentrations of inulin on ram sperm quality during cryopreservation

BACKGROUND: In reproductive biotechnology, sperm cryopreservation has a vital role to play. Cryopreservation of sperm produces reactive oxygen species (ROS), which disrupt sperm function and structural competence. Numerous protective chemicals, including fructans, have been used during sperm cryopreservation. OBJECTIVES: To evaluate the effect of different concentrations of the fructosan inulin on ram sperm quality parameters, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) production after freezing and thawing. MATERIALS AND METHODS: The pooled samples from four healthy rams were divided into seven equal aliquots and diluted in a Tris-base extender supplemented with 1, 2, 4, 8, 16, and 28 mM of inulin or without inulin supplementation (control). By using liquid nitrogen vapor, the semen was frozen and stored at 196°C. RESULTS: The total motility, viability, and DNA integrity were significantly improved after freezet-hawing with 28 mM inulin, compared to other treatment groups (P<0.05). A Tris-based extender containing 16 and 28 mM of inulin displayed the highest levels of ram sperm membrane integrity when compared with the control (p<0.05). The abnormality of ram sperm was increased during freeze-thawing at control and 1 mM of inulin, compared to 16 and 28 mM of inulin (P<0.05). Additionally, 28 mM of inulin decreased MDA and increased SOD activity in ram sperm in comparison with the other treatments (P<0.05). CONCLUSION: As a result, 28 mM of inulin could be beneficial for the cryopreservation industry and reduce the harmful effects of freeze-thawing on ram sperm.