The effects of addition of omega-3, 6, 9 fatty acids on the quality of bovine chilled and frozen-thawed sperm

This study was aimed to investigate the effects of omega-3, 6, 9 fatty acids on the characteristics of bovine chilled and frozen-thawed semen. For this purpose, oil containing different levels of omega-3, 6, 9 fatty acids were added to semen extender. To emulsify the oil in semen extender, polyethylene glycol (PEG) was added as a suitable solvent and the solution was finally sonicated. Five proven Holstein bulls were randomly selected and their ejaculates were collected using an artificial vagina. Groups were designed as control, treatments 1, 2, 3 and 4. The control group contained only the basic extender (Tris-citrate buffer, egg yolk and glycerol) without any additives. In treatment 1, only 5% PEG was added to the diluent; while in treatments 2, 3 and 4 different concentrations of omega-3, 6, 9 fatty acids (1.0, 2.5 and 5.0%) in combination with PEG were added to the basic extender. After dilution, the semen samples were packaged into 0.5 ml straws, a process that was followed by cooling the semen straws. Motility, viability and morphology of semen samples were evaluated after 24 and 48 h of storage in refrigerator (5 ˚C) or after one month of storage in the liquid nitrogen. Immotility was increased and all the other parameters including motility, viability and morphology were significantly decreased in all the groups compared with fresh samples during cold storage and freezing-thawing. Our results demonstrated the following: 1) PEG has significant detrimental effects, especially on the sperm motility; 2) addition of omega-3, 6, 9 fatty acids could not improve the sperm motility in chilled storage condition and after freezing-thawing; and 3) omega-3, 6, 9 fatty acidscould not also attenuate the other deleterious effects of PEG. In conclusion, our findings reveal that addition of these fatty acids to the semen extender does not enhance the resistance of the bovine sperm membrane to cooling and freezing-thawing and that further studies are required to find suitable candidate compounds that can boost the quality of semen that is chilled and freeze-thawed

Project Management Competences by Teaching and Research Staff for the Sustained Success of Engineering Education

Projects have become an essential instrument for the success of universities. In a context of globalization and increasing complexity, they must sharpen their resourcefulness to face these challenges and adapt to this changing environment. To reach these objectives, they undertake a series of activities of a unique, concrete and temporary nature, not always technical but managerial ones. If universities work with people on projects in the production, transmission and dissemination of knowledge, then they link with society to solve its problems. For this reason, teaching and research staff (TRS) should promote a range of professional project management (PM) competences in different areas for the proper management of the projects in which they take part. Through a Delphi technique, a panel of twenty-four accredited teaching experts who are carrying out significant research and holding directive roles, measured the importance of acquiring and/or improving professional PM competences by their TRS. Consensus and stability reached after two rounds of consultation confirmed there are a series of crucial competences for the practice of relevant teaching and pioneer research. Results obtained are the basis for a gap plan that allows the TRS to participate in and/or lead university projects with greater self-confidence and personal motivation

Electric Field

In the present book, various applications of electric field are introduced in health and biology like treating cancer and cell sorting and in engineering and technological applications like enhancing the heat transfer, colloidal hydrodynamics and stability, and lithography. Electric field is defined as a force field arising from the electric charges. Depending on the nature of the material (the ability to polarize) and the inherent or attained surface charges, the response of the electric field varies

HVAC System

In this book, various aspects of heating, ventilation, and air-conditioning (HVAC) systems are investigated. HVAC systems are milestones of building mechanical systems that provide thermal comfort for occupants accompanied with indoor air quality. HVAC systems can be classified into central and local systems according to multiple zones, location, and distribution. Primary HVAC equipment includes heating equipment, ventilation equipment, and cooling or air-conditioning equipment. Central HVAC systems are located away from buildings in a central equipment room and deliver the conditioned air by a delivery ductwork system. Central HVAC systems contain all-air, air-water, or all-water systems. Two systems should be considered as central such as heating and cooling panels and water-source heat pumps

Nanofluid Heat and Mass Transfer in Engineering Problems

In the present book, nanofluid heat and mass transfer in engineering problems are investigated. The use of additives in the base fluid like water or ethylene glycol is one of the techniques applied to augment heat transfer. Newly, innovative nanometer-sized particles have been dispersed in the base fluid in heat transfer fluids. The fluids containing the solid nanometer-sized particle dispersion are called ""nanofluids."" At first, nanofluid heat and mass transfer over a stretching sheet are provided with various boundary conditions. Problems faced for simulating nanofluids are reported. Also, thermophysical properties of various nanofluids are presented. Nanofluid flow and heat transfer in the presence of magnetic field are investigated. Furthermore, applications for electrical and biomedical engineering are provided. Besides, applications of nanofluid in internal combustion engine are provided

Microfluidics and Nanofluidics

In the present book, various applications of microfluidics and nanofluidics are introduced. Microfluidics and nanofluidics span a broad array of disciplines including mechanical, materials, and electrical engineering, surface science, chemistry, physics and biology. Also, this book deals with transport and interactions of colloidal particles and biomolecules in microchannels, which have great importance to many microfluidic applications, such as drug delivery in life science, microchannel heat exchangers in electronic cooling, and food processing industry. Furthermore, this book focuses on a detailed description of the thermal transport behavior, challenges and implications that involve the development and use of HTFs under the influence of atomistic-scale structures and industrial applications

Cooling process of liquid propellant rocket by means of kerosene-alumina nanofluid

Heat transfer augmentation of kerosene-alumina nanofluid is studied for the possible use in the regenerative cooling channel of semi cryogenic engine. The basic partial differential equations are reduced to ordinary differential equations which are solved using differential transformation method. Velocity and temperature profiles as well as the skin friction coefficient and Nusselt number are determined. The influence of pertinent parameters such as nanofluid volume fraction, viscosity parameter and Eckert number on the flow and heat transfer characteristics is discussed. The results indicate that adding alumina into the fuel of liquid rocket engine (kerosene) can be considered as the way of enhancing cooling process of chamber and nozzle walls. Nusselt number is an increasing function of viscosity parameter and nanoparticle volume fraction while it is a decreasing function of Eckert number