The objective of the research is to find low cost alternative for conventional recreational lagoons that consume water and energy used for desalination which is the only alternative for water treatment in most touristic villages all over the world. The study uses low cost recreational lagoon with new technology that use brackish water from deep wells and purify this water before entering the lagoon by controlled pulses and energy-efficient ultrasound filtration. This allows to maintain the water within pre-defined parameters, guaranteeing standardized water quality in all lagoons. The research introduces the lagoon new technology and its low cost design including feeding and drainage wells, second, the hydrographic survey-ing for the coastline in the study area, third water quality modelling for the production and injection wells, fourth, use SOBEK 1-2 Mathematical Model for determine the water depth and perspective water volume for the designed lagoon. The aim of this model: Determine the relation between the water depth and the water volume for the canal and the lakes. Sec-ond, calculate the evaporation rate from the surface, Determine the number and capacity of the water wells needed to fill the canal and the lakes, and Find out the relationship between the discharge and the time needed to circulate the water in the canal and the lakes to keep their water quality.

The results of the measurements from the observation well prove that the optimal discharge per each well is 0.022 m3·s–1. The construction of suggested new green technology lagoon are very low cost, completely environmentally friendly, in addition fulfils the highest standards of environmental safety.

Almost every construction investment should contain elements of risk forecasting, whose validity depends, among other things, on the correct assessment of potential threats. These risks were defined by the Authors as risk factors that were characterized and then grouped on the basis of performed research in the scope of their identification. Due to lack of method of scheduling railway investments on the construction market, including risk assessment, a research effort was undertaken [14-17], the result of which is the proposed method. The article presents the main assumptions of the original method of rail investment planning, which on the one hand, will take into account the impact of potential threats identified previously by the Authors, and, on the other, will allow project managers to refer to the conditions in which the implementation of a specific facility is planned. The assumption was made that the method, relatively easy to implement, supported by an appropriate computational program, will encourage teams planning the implementation of railway undertakings to its application and will improve the reliability of the schedules they develop.

The student of Ottoman Empire always keeps a watchful eye open for the rare, sometimes unique record which has somehow survived from the heyday of Ottoman historiography or archival treasuries and illuminates an aspect of history otherwise unknown to us. One such records concerns is the Book VI of Hašt Bihišt, written by Idrīs Bidlīsī (1457–1520), who is undoubtedly one of the most original and important intellectual figures in the Ottoman-Iranian borderland in the sixteenth-century. This paper deals with critical edition and translation of an unpublished tahniyat-nāma, given in Hašt Bihišt VI, which Bidlīsī dedicated to the first marriage of Mehmed II.

The paper presents equations of a mathematical model to calculate flow parameters in characteristic cross-sections in the steam-water injector. In the model, component parts of the injector (steam nozzle, water nozzle, mixing chamber, condensation wave region, diffuser) are treated as a series of connected control volumes. At first, equations for the steam nozzle and water nozzle are written and solved for known flow parameters at the injector inlet. Next, the flow properties in two-phase flow comprising mixing chamber and condensation wave region are determined from mass, momentum and energy balance equations. Then, water compression in diffuser is taken into account to evaluate the flow parameters at the injector outlet. Irreversible losses due to friction, condensation and shock wave formation are taken into account for the flow in the steam nozzle. In two-phase flow domain, thermal and mechanical nonequilibrium between vapour and liquid is modelled. For diffuser, frictional pressure loss is considered. Comparison of the model predictions with experimental data shows good agreement, with an error not exceeding 15% for discharge (outlet) pressure and 1 K for outlet temperature.

This paper presents the numerical solution to the unsteady natural convection problem in micropolar fluid in the vicinity of a vertical plate, heat flux of which rises suddenly at a given moment. In order to solve this problem the method of finite differences was applied. The numerical results have been presented for a range of values of the dimensionless material properties and fluid Prandtl number. The analysis of the results shows that the intensity of the heat transfer in micropolar fluid is lower compared to the Newtonian fluid.

Authors paid attention to anatomy and clinical implications which are associated with the variations of the sphenoid sinus. We discuss also anatomical structure of the sphenoid bone implementing clinical application of this bone to diff erent invasive and miniinvasive procedures (i.e. FESS).