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The operation of gas generators brings relatively high thermo-mechanical loads on the gas generator structure. The objective of this article is to determine the operating conditions, in terms of mechanical loads at extremely high temperatures in very limited and narrow space, of a multifunctional bulkhead for application on specific kinds of gas generators with back-to-back rotor concept. The paper contains numerical analysis and experimental investigation for determining the loads and behavior of the structure. Numerical analysis indicates that there is significant influence of the Tesla turbine effect on flow parameters. Also, uneven pressure distribution and significant thermal loads are identified. With experimental investigation and subsequent exploitation tests, it was concluded that the presented methodology identifies the operating conditions, truthfully simulates the bulkhead stress state and deformations and that the presented design solution satisfied all demands. Regarding results obtained by these numerical simulations, the innovative design solution for the multifunctional bulkhead was proposed.

Reducing natural resources caused by the growth of the world’s population, meeting the growing demands of consumers, and preventing environmental pollution requires the development of sustainable and efficient procedures that include the valorization of wastes [...]

Recently, a multiple-resonator structure was proposed as a robust and computationally efficient tool for harmonic analysis. Two trivial cases have been previously observed. The first case exhibits good out-of-band suppression and elimination of unwanted harmonics, but with a high latency. In the second case, a phase frequency response around the passband centre is zero-flat, that provides fast estimates. However, in this case, resonant peaks at the ends of the passband and high interharmonic gains cause large overshoots. In general, the basic algorithm performance requirements: selectivity and speed, are contradictory which makes it impossible to completely fulfil both of them. In this paper, the Constrained Linear Least-Squares (CLLS) optimization method is used to obtain a compromise solution. As a result, the resonant peaks in the passband are avoided and side lobes are mitigated, simultaneously minimizing the group delay in the middle of the passband. Performed simulations confirmed the effectiveness of the proposed algorithm.

Diverging notions of what is meant with and under narrative(s), it’s (their) function and use has been in the centre of research and practical attention in previous years especially regarding the narrative and rhetorical structure of urban theory, planning and design. The concept of narrative is ’’borrowed’’ from literary theory, where notion of narratology is commonly described as the study of narrative structure, looking at what narratives have in common and what makes one different from another.

Wearable power supply devices and systems are important necessities for the emerging textile electronic applications. Current energy supply devices usually need more space than the device they power, and are often based on rigid and bulky materials, making them difficult to wear. Fabric-based batteries without any rigid electrical components are therefore ideal candidates to solve the problem of powering these devices. Printing technologies have greater potential in manufacturing lightweight and low-cost batteries with high areal capacity and generating high voltages which are crucial for electronic textile (e-textile) applications. In this review, we present various printing techniques, and battery chemistries applied for smart fabrics, and give a comparison between them in terms of their potential to power the next generation of electronic textiles. Series combinations of many of these printed and distributed battery cells, using electrically conducting threads, have demonstrated their ability to power different electronic devices with a specific voltage and current requirements. Therefore, the present review summarizes the chemistries and material components of several flexible and textile-based batteries, and provides an outlook for the future development of fabric-based printed batteries for wearable and electronic textile applications with enhanced level of DC voltage and current for long periods of time.

Climate change is not a matter of the future. These are processes that are already happening and have the most unfavorable impact on the water sector in Serbia, but also in all countries in the region. Unfavorable consequences are especially pronounced in Serbia, because it has previously had water regimes among the most unfavorable in Europe - from the point of view of time unevenness during the year, as well as from the point of view of spatial distribution of water on the territory. As a consequence of climate change, deterioration of water regimes is already being registered: dry periods are getting longer, small waters are getting smaller and with longer duration, big waters are getting bigger, more torrential, with more and more devastating consequences, groundwater renewal intensity is decreasing and becoming more more vulnerable groundwater sources. It is especially bad that the biggest deteriorations of water regimes are in parts of Serbia (east, southeast, south), where water regimes are still the most unfavorable. The current planned actions in the world are limited to efforts to slow down greenhouse gas (GHG) emissions. These actions are not operational enough for the water sector. Achieving the necessary resilience of water management systems can only be achieved through new accumulation and strengthening of line flood protection systems. Reservoirs are gaining an increasing role in active flood protection - by mitigating flood waves. In such conditions, the absolute priority is spatial planning, which will protect all the necessary spaces for the development of water management infrastructure in the new, worsened conditions. This includes planned protection of the space necessary for the construction of new reservoirs and retentions, protection of all groundwater and surface water sources, and space for strengthening line flood protection systems. Based on studies done for the Spatial Plan of the Republic of Serbia and the Study of the Impact of Climate Change on the Water Management of the Vrbas Basin, the article analyzes the need to build new reservoirs in order to make water management systems sufficiently reliable and resilient and in new conditions. The example of the Vrbas and its tributaries the Vrbanja shows that the construction of smaller reservoirs, instead of large ones, the realization of which is prevented by unplanned occupation of the valley area, can significantly increase the reliability of the irrigation system. Experiences from Serbia are also cited, which must provide the new reservoirs with the necessary reliability of water management systems in the new, worsened conditions caused by climate change. Klimatske promene nisu stvar neke dalje budućnosti. To su procesi koji se već dešavaju i najnepovoljnije se odražavaju upravo na sektor voda u Srbiji, ali i u svim zemljama u regionu. Nepovoljne posledice su posebno izražene u Srbiji, jer je ona i ranije imala vodne režime među najnepovoljnijim u Evropi - sa gledišta vremenske neravnomernosti tokom godine, kao i sa gledišta prostorne raspodele vode po teritoriji. Kao posledica klimatskih promena već se uočavaju pogoršanja vodnih režima: sušni periodi postaju sve duži, male vode su sve manje i sa sve dužim trajanjem, velike vode postaju sve veće, bujičnije, sa sve razornijim posledicama, smanjuje se intenzitet obnavljanja podzemnih voda i postaju sve ranjivija izvorišta podzemnih voda. Posebno je loše to što su najveća pogoršanja vodnih režima upravo u delovima Srbije (istok, jugistok, jug), gde su i sada vodni režimi najnepovoljniji. Sadašnje planirane akcije u svetu svode se samo na napore da se uspore emisije gasova staklene bašte (GSB). Te akcije nisu dovoljno operativne za sektor voda. Ostvarivanje potrebne izdržljivosti (resiliency) vodoprivrednih sistema može se ostvariti samo novim akumulacijama i ojačanjem linijskih sistema zaštite od poplava. Akumulacije dobijaju sve veću ulogu i u aktivnoj zaštiti od poplava - ublažavanjem poplavnih talasa. U takvim uslovima apsolutni prioritet ima prostorno planiranje koje će zaštititi sve neophodne prostore za razvoj vodoprivredne infrastrukture u novim, pogoršanim uslovima. To podrazumeva plansku zaštitu prostora neophodnih za izgradnju novih akumulacija i retenzija, zaštitu svih izvorišta podzemnih i površinskih voda, i prostora za ojačavanje linijskih sistema zaštite od poplava. U članku se na bazi studija urađenih za Prostorni plan Republike Srbije, i Studije uticaja klimatskih promena na upravljanje vodama sliva Vrbasa, analizira neophodnost izgradnje novih akumulacija, kako bi se vodoprivredni sistemi učinili dovoljno pouzdanim i izdržljivim i u novim uslovima. Na primeru Vrbasa i njegove pritoke Vrbanje pokazuje se da se izgradnjom i manjih akumulacija, umesto velike, čija je realizacija onemogućena neplanskim zaposedanjem dolinskog prostora, može značajno povećati pouzdanost funkcionisanja sistema za navodnjavanje. Navode se i iskustva iz Srbije, koja mora novim akumulacijama obezbediti neophodnu pouzdanost vodoprivrednih sistema u uslovima izazvanim klimatskim promenama.

It is known that meteorological variables from meteorological online services can be used for the design of photovoltaic (PV) water pumping systems for irrigation. The software LORENTZ COMPASS in such a manner uses as inputs solar irradiation, precipitation, and ambient temperature collected by the NASA Langley Research Centre over a period of more than 20 years. This paper proposes a novel procedure that uses the sunshine duration, precipitation, and ambient temperature as inputs. These inputs were collected by Weather Online UK during a period of 25 years. The effects of different data collection periods and data availabilities on the design of the PV water pumping system are also analysed and discussed. Along with the meteorological data, the proposed procedure uses as inputs datasheets from manufacturers of pumping systems and PV modules. The procedure is based on the Sivkov model that correlates the global horizontal irradiation with the sunshine duration and the elevation angle of the Sun. A case study, i.e., an existing PV water pumping system designed using LORENTZ COMPASS is used as reference for purposes of comparison and validation of the procedure. The results of the comparison showed a high level of accuracy, and a number of interesting conclusions are drawn from them.