Electromagnetic compatibility in various kinds of substations in Croatian transmission networks and mitigation measures

In the last two decades have been studied the conditions of electromagnetic compatibility (EMC) in different kind of substations in transmission networks of Croatia. Investigations have been done by measuring method using special measuring technique and also by computing simulations. In this paper will be shown conditions of EMC which have been studied by measuring method during normal or fault switching operations of disconnectors and circuit breakers. Conditions of EMC with particular stress on transient voltages in secondary circuits within various kind of transmission network objects have been carefully studied (AIS, GIS, old and new substation design type, rated voltages from 110 kV to 400 kV). In the paper will be given the review of some main data from those investigations made in the long period of time. Then main findings will be given and the differences in EMC conditions will be shown taking into account various parameters such as: design details of substations (distances, cable types, protective measures etc.). Also, it will be given a review of measuring methods and tools (oscilloscopes with low and deep acquisition memory, statistical tools for data processing, etc.). Generally, it was shown that overvoltatges in secondary equipment follows normal or Gaussian statistical distribution from which some typical data have been taken, such as 98% - probability values etc. Consequently, different kind of the mitigation measures have been proposed in cases of high overvoltages in secondary circuits. Typically, changes in earthing systems, in cable sheets connections etc. have been proposed to utilities. All proposed measures have been tested by measuring methods too and the effects have been very satisfactory in ensuring EMC conditions within substations. Some most interesting ways in reducing high level of TEVR in GIS substations will be shown in pictures. Given results and effects of mitigation measures in Croatian transmission network substations clearly show that the best method is experimental investigation which usually was followed by some necessary mitigation measures which ensure the conditions of EMC within substations according to international standards and recommendations

The out-of-court procedure for enforcement of hypothec

Предмет докторске дисертације је дефинисање суштинског значења вансудске реализације хипотеке из хипотековане непокретности. Зато обухвата хипотекарову власт да сâм, односно да овлашћено лице покрене процесноправни механизам уновчења хипотековане непокретности, од момента кад облигациони дужник западне у доцњу и изазове законом и/или уговором предвиђене услове за активацију хипотекареве власти. Та установа потпуно искључује улогу или бар надзор суда или другог органа државне власти, што значи да целокупан поступак има све битне елементе, по нарави – приватног извршења. Ту власт хипотекар изводи непосредно из закона. Наиме, законски је концепт да хипотекар ex lege стиче дискрециону власт да сâм или посредством овлашћеног лица које се уговором именује за „независно и професионално лице“: прво, да оцени доспелост потраживања; друго, да процени висину свога потраживања; треће, да утврди цену хипотековане непокретности; четврто, да је уновчи. Хипотекар има и ex lege власт да на аукцији својим потраживањем сâм купи од овлашћеног лица хипотековану непокретност. То овлашћено лице се именује у фази обезбеђења потраживања као главни услов да корисник кредита или зајмопримац уопште добије тражени кредит/зајам. У тој фази обезбеђења потраживања није спорно да су стране у неједнаком положају, да је посреди адхезиони уговор – припремљен и састављен по диктату хипотекара. Не може бити спорно ни то да, изузев свих осталих уговорних састојака, хипотекар, подразумевано, овлашћује лице од поверења које ће испуњавати његове захтеве. Притом, тако овлашћено лице није независно, иако га законодавац у Закону о хипотеци Србије предвиђа као лице које се професионално бави пословима који спадају у његову редовну делатност, а у Закону о извршењу и обезбјеђењу Црне Горе дословно: јавни извршитељ, адвокат и агенција за промет непокретности. У Србији то лице наступа по самој сили закона као „законски заступник“ власника хипотековане непокретности, а у Црној Гори наступа „у име“ власника хипотековане непокретности. Те законске „спојнице“ овлашћеног лица с власником хипотеке непокретности откривају сву суштину проблема. Обе земље су, по сопственим признањима, такав процесни механизам преузеле из правне установе mortgage (даље: моргиџ) карактеристичне за систем common law, односно из права Сједињених Америчких Држава. Међутим, сада је јасно да се није водило рачуна о правној структури моргиџа и, још више, о бројним особеностима система common law, наспрам система civil law. Наши законодавци се нису повели чињеницом да ту установу, то јест процесни механизам који се одвија у приватној режији, ипак није преузела ниједна земља Евопске уније, односно система civil law, где је тај независан трећи субјект, по традиционалном правилу, суд или пак субјекти под будним надзором суда. Тим путем је у наше правне поретке закорачио својеврстан реметилачки правни иритант, који је и нарушио и оштетио наше ионако крхке правне системе.The subject of doctoral dissertation is the definition of the constitutive meaning of the out-of-court enforcement of hypothec from the mortgaged immovable property. Hence, it includes a mortgagee’s power to institute on his own, or by an authorized person, a procedural-law mechanism of collecting a pecuniary claim out of a mortgaged property from the moment when the enforcement debtor is in default to pay the debt and causes the law and/or contract prescribed stipulations for putting the mortgagee’s authorization into enforcement. A concrete institution completely excludes the role or at least the custody of the Court or other state body which means that the whole procedure in nature has all the necessary elements of private enforcement. An authorization to do so by a mortgagee directly arises from the Law. Namely, the Law has been conceptualized in a way that the mortgagee ex lege acquires a discretionary authority to appraise that the claims are being due for payment by himself or with an authorized person being appointed as “an independent and professional person” prescribed by the Agreement; the second - to appraise the amount of his claims; the third - to determine the value of his claims; and the fourth - to cash it. Mortgagee has also an ex lege authority to “purchase” a mortgaged property by means of his own claims on a public auction. Such authorized person is appointed at a phase when claims are being secured as a precondition for credit beneficiary or a borrower to be granted a concerned credit/ loan. At that phase of securing the claims it’s not disputable that parties may be in an unequal position, that it is in force an Adhesive Agreement – upon a mortgagee’s order. It may also not be disputable that, except all other contract elements, that a mortgagee may authorize a person who will meet his requests. Besides, such authorized person cannot act independently, irrespective of the fact that they are being provided for as a person who professionally performs his own tasks which fall within his regular activity by the Law on Mortgage of the Republic of Serbia, where in the Montenegrin Law on the Enforcement and Securing of Claims literally provides for as a public enforcement officers, attorneys at law and estate agencies. In Serbia such person who acts by virtue of law is a “legal representative” of the owner of a mortgaged property. And in Montenegro he acts “on behalf” of the owner of mortgaged property. Such legal “joints” of authorized person with the owner of mortgaged property reveal the nature of the problem. Both countries avowedly have adopted a concerned procedural mechanism from the legal institution Mortgage Common Law System which falls within USA Law. However, now it is obvious that our lawmakers didn’t take care about a legal structure of mortgage and numerous particularities of Common law system in relation to Civil law system. Our lawmakers were not guided by the fact that this institution, that is a procedural mechanism which is carried out in private was not adopted by any other EU country, respectively a Civil law system where that independent third party is traditionally a court or an entity under the custody of a court. In such way, a legal irritant has been introduced into our legal system and both violated and affected our already fragile legal systems. This legal transposition of the out-of–court enforcement of hypothec has stirred up “an endless suit” among circles of legal practitioners as well as deviations in practice. An immense room for miscellaneous malpractices has opened

First Experience in Monitoring of Line Surge Arresters Installed on 110 kV Transmission Line Ston – Komolac in Croatia

In paper are presented some first results and experience in real time monitoring of line surge arresters installed on 110 kV transmission line Ston – Komolac in southern part of Croatia. Mentioned line is the first line in Croatian transmission network equipped with line surge arresters (LSA). The line with its length of 43,95 km is situated in region with high soil resistance, exposed to one of the highest level of lightning activity in Croatia. At the same time it is the most important line in connecting HPP Dubrovnik (240 MVA) to the main part of 110 kV transmission network. Due to all mentioned reasons and great number of annual outages, it was decided to equip the line with LSA for improving the lightning performance and the availability of line. As result of performed numerical simulations on simulation line model it was decided to install 110 kV gapless, IEC Class II line arresters. Also, to improve analysis of expected results the 61 line arresters were equipped with Excount-II type of monitoring sensors. The main goal was to determine the behaviour of line arresters arrangement across the line during overvoltage events on towers. This installed “realtime” monitoring system enables remote control and wireless exchange the collected data from local data logger installed on LSA. Line arresters activity is monitoring through numbers, date and time and level of surges and the condition state of LSA, through the measuring of leakage current. First results in application of LSA are showing significant reduction of line outages with registered relatively strong activity of monitored line arresters. Also, as it was expected some particular part of line is espied to be exposed to higher frequency and higher level of registered arresters surge current. During collecting the data of LSA activity, some practical problems were encountered with time synchronization between monitoring devices and it is mentioned and discussed in paper, too. Although the analysed time period of eight months with LSA application is too short to allow strong final conclusions, obtained first experience will be very helpful in assessment of further LSA application in Croatian transmission network

Effective determination of clomazone and oxyfluorfen in aqueous samples by differential pulse stripping voltammetry

Two novel types of electrochemical sensors were obtained by chemical deposition of Pt and MoO2 nanoparticles onto multi walled carbon nano tubes (MWCNT) and used for determination of frequently used pesticides clomazone and oxyfluorfen in aqueous media via differential pulse stripping voltammetry (DPSV). Clomazone was determined in 0.1 M phosphate buffer solution at pH 7.0 in the concentration range 0.61-20.56 ng cm-3, with LOQ = 0.61 and LOD = 0.38 ng cm-3. Oxyfluorfen was determined with good reproducibility (RSD <2.4%) in the concentration range 2.5-34.5 ng cm-3, with r = 0.99 and a LOQ of 1.5 ng cm-3. Results were in the same range measured by HPLC/DAD, which was used as comparative method. Structural characterization of the dopped MWCNT performed by Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron (HR-TEM), and X-ray crystallography revealed a preserved MWCNT structure decorated with well dispersed species of the platinum and MoO2 nanoparticles.IX International Scientific Conference "Technics. Technologies. Education. Safety"; June 07-10, 2021; Borovets, Bulgari

First Experience in Monitoring of Line Surge Arresters Installed on 110 kV Transmission Line Ston – Komolac in Croatia

In paper are presented some first results and experience in real time monitoring of line surge arresters installed on 110 kV transmission line Ston – Komolac in southern part of Croatia. Mentioned line is the first line in Croatian transmission network equipped with line surge arresters (LSA). The line with its length of 43,95 km is situated in region with high soil resistance, exposed to one of the highest level of lightning activity in Croatia. At the same time it is the most important line in connecting HPP Dubrovnik (240 MVA) to the main part of 110 kV transmission network. Due to all mentioned reasons and great number of annual outages, it was decided to equip the line with LSA for improving the lightning performance and the availability of line. As result of performed numerical simulations on simulation line model it was decided to install 110 kV gapless, IEC Class II line arresters. Also, to improve analysis of expected results the 61 line arresters were equipped with Excount-II type of monitoring sensors. The main goal was to determine the behaviour of line arresters arrangement across the line during overvoltage events on towers. This installed “realtime” monitoring system enables remote control and wireless exchange the collected data from local data logger installed on LSA. Line arresters activity is monitoring through numbers, date and time and level of surges and the condition state of LSA, through the measuring of leakage current. First results in application of LSA are showing significant reduction of line outages with registered relatively strong activity of monitored line arresters. Also, as it was expected some particular part of line is espied to be exposed to higher frequency and higher level of registered arresters surge current. During collecting the data of LSA activity, some practical problems were encountered with time synchronization between monitoring devices and it is mentioned and discussed in paper, too. Although the analysed time period of eight months with LSA application is too short to allow strong final conclusions, obtained first experience will be very helpful in assessment of further LSA application in Croatian transmission network

Učinci hiperbaričnog kisika na vidne funkcije u bolesnika s ishemičnom optičkom neuropatijom

The effects of hyperbaric oxygen therapy were studied in nine patients with non-arteritic anterior ischaemic optic neuropathy, who had been unsatisfactorily treated with corticosteroids. In four patients with signs of optic disc atrophy there was no improvement of visual functions after hyperbaric oxygen treatment, whereas in the other five patients, who had no signs of optic disc atrophy, visual acuity and visual field improved. The achieved improvements were maintained al a control examination six months later. Results suggest that hyperbaric oxygen might be a new remedy for the selected cases of non-arteritic ischaemic optic neuropathy and call for a controlled clinical study aiming to acurately assess its efficacy.Ispitivani su učinci tretmana hiperbaričnim kisikom u devet bolesnika s nearteritičinim oblikom prednje ishemične optikoneuropatije, koji su prethodno liječeni kortikosteroidima bez uspjeha. U četiri bolesnika sa znakovima atrofije optičkog diska, nakon tretmana hiperbaričnim kisikom, nije nađeno nikakvo poboljšanje vidnih funkcija, dok je u ostalih pet, bez znakova atrofije optičkog diska, ustanovljeno poboljšanje oštrine vida i vidnog polja. Ova poboljšanja nađena su i na kontrolnom pregledu nakon šest mjeseci. Rezultati ispitivanja sugeriraju hiperbaričnu oksigenaciju kao moguć način liječenja selekcioniranih slučajeva nearteritičnog oblika ishemične optikoneuropatije, kao i kontrolirani klinički pokus, radi egzaktnijeg utvrđivanja efikasnosti hiperbarične oksigenacije u ovih bolesnika

Structure and immunohistochemistry of the human lenticulostriate arteries

Background: Data about the structure and immunohistochemistry of the lenticulostriatearteries (LSAs), although very important for medical research and clinicalpractice, have been rarely reported in literature.Materials and methods: Fourty serially sectioned LSAs were stained with hematoxilinand eosin, and prepared for immunohistochemistry.Results: Our examination revealed a typical endothelial lining and a narrow subendothelialspace with subintimal smooth muscle cells occasionally. The internalelastic lamina was fragmented or absent in the smallest LSAs branches. The mediacoat, with a mean diameter of 148.5 μm, contained typical smooth muscle cellswhich formed 14.2 layers on average and showed a positive immune reactions foralfa-actin, desmine, laminin and collagen IV. The thin adventitial coat containedfibroblasts, collagen fibers, and nerve bundles, with the strongest immunopositivityto thyrosin hydroxilase. The immune reactions against CD31 and CD34 proteins,endothelial nitric oxide synthase, S 100 protein, neurofilament protein and synaptophysin,seem to be performed in the LSAs wall for the first time. Similarly,the thickness of the LSAs wall and its coats have never been reported, nor thenumber of the smooth muscle cell layers.Conclusions: Our results related to the structure and immunohistochemistry ofthe LSAs could be important in cerebrovascular pathology, neurology and neurosurgery

THE RELATIONS BETWEEN MECHANISMS OF THE REGULATION OF MOVEMENT AND THE COGNITIVE ABILITIES OF HANDBALL PLAYERS OF VARIOUS RANKS OF COMPETITION

Abstract On a sample of 180 handball players divided into 3 subsamples number 60 participants each, who belong to the I, II and republic handball league of Serbia,a system of 9 variables (6 motor and 3 cognitive) was applied with the aim of determining the statistically significant relations between the system of variables of motor and cognitive variables. The data were processed using a canonical correlation analysis. Using Bartlett’s Chi-square test for handball players of various ranks of competition we tested the statistical significance of the coefficients of the canonical correlation which explains the linear combinations between the groups of variables, that is, the connection between two systems of variables. By solving the characteristic equations of the cross-correlation matrix we obtained, as the roots of these equations, the coefficients of the determination of the canonical correlation for I league handball players (Rc2=.23, Rc2=.10, Rc2=.08), for II league handball players (Rc2=.24) and national level handball players (Rc2=.23). By analyzing the obtained canonical factors of both groups of variables we may say that the cognitive mechanisms have a certain significance for achieving success in handball, at the level of concrete, individual and isolated motor and cognitive abilities, and thus of the greatest importance for handball in general, irrespective of the level of the competition and level of success. A further more detailed study of the connection between the effectiveness of the parallel processor which is responsible for the visual spatialization and the factor of the structuring of movement is needed. Key words: handball, intelligence, motor skills

An Extended Evaluation of Schema Issues Advisor in the Azure SQL Database

The analysis of the telemetry data in Azure SQL database has revealed that most of the problems affecting the customers are due to the schema inconsistency errors. An assumption has been made that direct e-mail notifications sent to the customers about the current problems could significantly shorten time to resolve them. The prospective benefits are first validated by sending e-mail recommendations manually. Then, in an iterative way, the schema issue advisor that detects anomalies and automatically sends the appropriate notifications to the customers is implemented on top of Azure resources. Finally, an extended evaluation has confirmed the expected benefits of direct communications with the customers

Leaching of chromium from chromium contaminated soil: Speciation study and geochemical modeling

Distribution of chromium between soil and leachate was monitored. A natural process of percolating rainwater through the soil was simulated in the laboratory conditions and studied with column leaching extraction. Migration of chromium in the soil is conditioned by the level of chromium soil contamination, the soil organic matter content, and rainwater acidity. Chromium (III) and chromium(VI) were determined by spectrophotometric method with diphenilcarbazide in acidic media. Comparing the results of chromium speciation in leachate obtained by experimental model systems and geochemical modelling calculations using Visual MINTEQ model, a correlation was observed regarding the influence of the tested parameters. Leachate solutions showed that the concentration of Cr depended on the organic matter content. The influence of pH and soil organic matter content is in compliance after its definition through experimental and theoretical way. The computer model - Stockholm Humic Model used to evaluate the leaching results corresponded rather well with the measured values