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This research deals with thermal effect of hot and cold storage materials for a cooling system operating by an absorption cooling cycle of lithium bromide-water with a capacity of 4 tons. The heat needed to operate the system was gain from a solar parabolic concentric collector. It heats the hot tank through which it operates the generator of absorption cycle, which is the first part of the system. The extra heat is stored in hot tank as well as a cold tank is used to store the extra cooling capacity for air-conditioning a certain space of (80 m²). The best volume for the hot and cold storage tanks has been chosen along with the solar collector used with the appropriate coefficient of performance, which is determined after simulating the absorption cycle. When the system stops working and this occurs when the temperature of the hot tank is less than (65 ℃), then the cold tank performs air-conditioning process. The hot tank volume has been resized (from 0.55 m³ to 1.4 m³) as well as changed the area of solar collector to give the highest temperature that the hot tank could reach with a variation cooling load, which was calculated hourly by Carrier_HAP420 software during the day. The effect of these coefficients has been studied and analyzed separately by setting the area of solar collector and hot tank capacity and changing the volume of cold tank (from 0.9 m³ to 1.5 m³) that receives the extra cooling capacity. The system has been simulated by simplifying and deriving all related equations of thermal balances for hot and cold tanks, solar collector and cooling system with all its parts. The simulation has been performed to predict the best fluid performance used in both tanks. The glycerin was chosen because its withstands high temperatures in hot tank and the very low temperatures in cold tank. The most appropriate volume for hot storage tank is (0.55 m³) when the area of solar collector is (11.7 m²), working to cover (13) hours from 9 a.m. to 10 p.m. The most appropriate volume for cold storage tank is (1.5 m³), giving (3) working hours from 10 p.m. to 12 a.m. [ABSTRACT FROM AUTHOR]

Tanks are building structures that are used mainly for capturing and treating water but also other liquids. Different materials and shapes are used for their construction, also the use of tanks can be different. The floor plan shapes of the tanks depend mainly on the purpose of use, on the technological process taking place in the tank, and the method of construction as well. The most common floor shapes of tanks are rectangular, polygonal, circular, or other. Tanks with a circular floor plan are advantageous from both the static, but also an economic point of view. The construction of the bottom depends on the properties of the subsoil, groundwater, exploitation and dimensions of the tank, and due to the stored liquid. The thickness of the bottom depends on the compressibility of the soil. In this paper, the wall of a concrete cylindrical tank is assessed for different types of support, for different load cases using the RFEM computer program. Gradually, the volume of water in the tank, and the depth of immersion of the tank into the foundation soil will change. Extremes will be considered, full tank not buried - empty tank completely buried, but also other load combinations. In the case of foundation soil, a one-parameter subsoil model is considered, for which it is necessary to calculate the compressibility coefficient of the subsoil. Finally, a comparison and selection of the design of the tank foundation, which is the most advantageous for the given construction, is given. [ABSTRACT FROM AUTHOR]

From August, 1919 to January 3, 1920, Latvian, Lithuanian, Polish and the Red armies were involved in battles for Daugavpils. The battles were fought in several phases - in August 1919 (the first phase), September, 1919 (the second phase), and January, 1920 (the third phase). By the end of 1919, Daugavpils suburbs on the left bank of the Daugava were under the control of Lithuanian and Polish armed forces, while the right bank of the Daugava and the city of Daugavpils were controlled by the Red Army. The periodical press of that time may prove useful to the investigation of these battles. In 1919, more than 65 different newspapers, newssheets, and journals were published in Latvian. The most important party newspapers at a national level at this time were "Sociāldemokrāts", "Brīvā Zeme", "Baltijas Vēstnesis", "Tautas Balss", non-party newspapers "Jaunākās Ziņas", "Latvijas Sargs", the official paper "Valdības Vēstnesis", and the Bolshevik daily "Krievijas Cīņa" which was published in Moscow. The tradition of issuing regional newspapers was only at the stage of development yet. In 1919, just a few numbers of the Latgalian paper "Latgolas Vords" were issued. A new feature of the development of press was a foundation of Latvian Press Bureau (LPB) "Latopress" in 1919. The task of LPB was to inform world news agencies and local media about the events taking place on the territory of Latvia. Making use of information broadcast by the Moscow (Soviet Russia) and Neuen (Germany) radios, LPB prepared news reports and published them in Latvian newspapers. These reports included the infor­mation about military operations at Daugavpils as well. The information about the events at Daugavpils published in periodicals can be classified into several relative groups. First, newspapers published front reports by the General Headquarters of armies on the advancement of armed forces to Daugavpils, on battles at the settlements near Daugavpils. Second, the readers were informed about the rivalry between Lithuanian and Polish armies in fight for the influence in the region and also about the battles for Daugavpils. Third, as much as it was possible, readers were given infor- mation about the proportion of the forces of warring parties, armament, and also spirits. Fourth, newspaper columns also reflected an important battle episode - the use of French tanks by the Polish army. Maintaining lively interest about the events taking place in Daugavpils, newspapers, however, occasionally published unchecked and even false news, including the occupation of Daugavpils. Then this news was checked and called off. The newspaper information on the events on the front, given under the conditions of military operations, has to be evaluated quite critically. Though considering that Latvian press is a valuable source of history, a more extensive research on the events in Daugavpils suburbs in 1919 would be desirable nevertheless. The information about the events on the front, given by newspapers of different political orientation under the conditions of military operations, is to be evaluated critically, since the phenomena are reflected from the stand­point of warring parties. [ABSTRACT FROM AUTHOR]