Construction of the Water Supply System of the Požega Area for Conditions of Maximum Use of the Well Field on the Foothills of Papuk

Ovim radom prikazan je razvoj vodoopskrbnog sustava Požeštine, posebno mogućnosti korištenja voda s izvorišta na obroncima Papuka, od njegove hidrauličke koncepcije sve do potrebe za daljinskim upravljanjem i kontrolom toka vode. Specifičnost tzv. „brdskih“ izvorišta jest visoka kakvoća vode, ali i promjena izdašnosti u periodu ljeto – zima. Vodoopskrbna konfiguracija u načelu je izgrađena tako da je moguće koristiti se tim vodama, no za njihovu maksimalnu iskoristivost u uvjetima proširenja vodoopskrbnog sustava i uključivanja novih potencijalnih brdskih izvorišta potrebno je ugraditi odgovarajuće regulacijske ventile i postaviti algoritme rada kako bi se vodoopskrba u što većoj mjeri automatizirala.The Požega area was always characterised by scarcity of wate for human use in the summer months. The current well fields can be divided into well fields in the lowland areas by the Orljava river and hillside water intakes on the foothills of Papuk. Even though the area of Papuk has a relatively large catchment area, due to its specific geological structure there is no possibility for significant accumulation of groundwater that could be used for water supply to the population throughout the year. However, water from hillside water intakes is of high quality and, due to its elevation, enables water supply without spending additional energy, which is an element that they aimed and still aim to make maximum use of. Thus for a number years the water supply structure has been developed so as to enable receiving hillside water in all seasons and, if necessary, supplement it with water from the well field in the Orljava river valley. Recent hydrogeological research showed that, by drilling deeper in the Papuk hills, additional quantities of water can be encountered that could be, with additional energy consumption, used in the summer months when water shortages occur regularly, which is also an additional burden on the expansion of the public water supply system in the entire Požega area. Inclusion of such well fields in hillside parts of the water supply system with maximum use of existing hillside water intakes would be made possible by forming an adequate water supply structure but, more importantly, by managing and controlling the flow of water from available sources. In order for that to be possible it is necessary to properly install appropriate regulation valves at precisely selected locations that would be connected to the SCADA system. This system, but also adequate algorithms for operation of the water supply system, shall enable maximum use of water of high quality that complies with all requirements of the current Ordinance on Sanitary Quality of Drinking Water and, due to elevation, enables mostly gravity water supply that reduces energy consumption

Uparena optimizacijska metoda

U ovom članku analiziramo metode gradijentnog i zrcalnog spusta u području konveksne optimizacije s danim naglaskom na njihove brzine konvergencije. Nadalje, uparujući dvije spomenute metode dobivamo takozvanu uparenu metodu čija analiza konvergencije pokazuje ubrzanje u odnosu na gradijentnu i zrcalnu metodu, te bilo koju drugu nama poznatu metodu prvoga reda

The influence of spring valve on the efficiency of water supply systems

Analizirane su karakteristike rada i učinkovitost ventila za regulaciju nizvodnog tlaka s posebnim osvrtom na mehaničke opružne ventile. Iznesene su teoretske osnove rada opružnih ventila s kritičkim osvrtom na njihovu funkcionalnost i učinkovitost u usporedbi s hidrauličkim ventilima. Na konkretnim primjerima dan je usporedni prikaz rada opružnih i hidrauličkih ventila za regulaciju tlakova s aspekta generiranja određenih hidrauličkih stanja i učinkovitost u upravljanju vodnim gubitcima. Dobiveni rezultati upućuju na potrebu da se opružni ventili zamijene hidrauličkima.The operating characteristics and efficiency of the valve used for regulation of downstream pressure are analysed, and a special emphasis is placed on mechanical spring valves. Theoretical notions about operation of spring valves are given, with a critical review of their functionality and efficiency as compared to hydraulic valves. Spring valves and hydraulic valves are compared on real-life examples with regard to their use for regulation of pressure from the aspect of generation of specific hydraulic states and efficiency in water loss management. The results obtained in this research point to the need to replace spring valves with hydraulic valves

Faraday tomography of LoTSS-DR2 data: I. Faraday moments in the high-latitude outer Galaxy and revealing Loop III in polarisation

Observations of synchrotron emission at low radio frequencies reveal a labyrinth of polarised Galactic structures. However, the explanation for the wealth of structures remains uncertain due to the complex interactions between the interstellar medium and the magnetic field. A multi-tracer approach to the analysis of large sky areas is needed. This paper aims to use polarimetric images from the LOFAR Two metre Sky Survey (LoTSS) to produce the biggest mosaic of polarised emission in the northern sky at low radio frequencies (150 MHz) to date. The large area this mosaic covers allows for detailed morphological and statistical studies of polarised structures in the high-latitude outer Galaxy, including the well-known Loop III region. We produced a 3100 square degree Faraday tomographic cube using a rotation measure synthesis tool. We calculated the statistical moments of Faraday spectra and compared them with data sets at higher frequencies (1.4 GHz) and with a map of a rotation measure derived from extragalactic sources. The mosaic is dominated by polarised emission connected to Loop III. Additionally, the mosaic reveals an abundance of other morphological structures, mainly {narrow and extended} depolarisation canals, which are found to be ubiquitous. We find a correlation between the map of an extragalactic rotation measure and the LoTSS first Faraday moment image. The ratio of the two deviates from a simple model of a Burn slab (Burn 1966) along the line of sight, which highlights the high level of complexity in the magnetoionic medium that can be studied at these frequencies.Comment: 20 pages, 25 figures, accepted for publication in A&

LOFAR Deep Fields: Probing faint Galactic polarised emission in ELAIS-N1

We present the first deep polarimetric study of Galactic synchrotron emission at low radio frequencies. Our study is based on 21 observations of the European Large Area Infrared Space Observatory Survey-North 1 (ELAIS-N1) field using the Low-Frequency Array (LOFAR) at frequencies from 114.9 to 177.4 MHz. These data are a part of the LOFAR Two-metre Sky Survey Deep Fields Data Release 1. We used very low-resolution ($4.3'$) Stokes QU data cubes of this release. We applied rotation measure (RM) synthesis to decompose the distribution of polarised structures in Faraday depth, and cross-correlation RM synthesis to align different observations in Faraday depth. We stacked images of about 150 hours of the ELAIS-N1 observations to produce the deepest Faraday cube at low radio frequencies to date, tailored to studies of Galactic synchrotron emission and the intervening magneto-ionic interstellar medium. This Faraday cube covers $\sim36~{\rm deg^{2}}$ of the sky and has a noise of $27~{\rm \mu Jy~PSF^{-1}~RMSF^{-1}}$ in polarised intensity. This is an improvement in noise by a factor of approximately the square root of the number of stacked data cubes ($\sim\sqrt{20}$), as expected, compared to the one in a single data cube based on five-to-eight-hour observations. We detect a faint component of diffuse polarised emission in the stacked cube, which was not detected previously. Additionally, we verify the reliability of the ionospheric Faraday rotation corrections estimated from the satellite-based total electron content measurements to be of $~\sim0.05~{\rm rad~m^{-2}}$. We also demonstrate that diffuse polarised emission itself can be used to account for the relative ionospheric Faraday rotation corrections with respect to a reference observation.Comment: 15 pages, 15 figures, accepted for publication in A&