Širokopojasni prijenos podataka elektroenergetskom mrežom

The paper presents an overview to broadband over powe lines. Over the past few years advances in signal processing technology have enabled the advent of modem chips that are able to overcome the transmission difficulties associated with sending communications signals over electrical power lines. There are two predominant types of BPL communications configurations: Access BPL and In-Home BPL. One of the largest commercial markets for BPL is the ability to provide Internet Services by means of the Transmission Control Protocol/Internet Protocol (TCP/IP) protocols. Another significant benefit of BPL is the ability to employ “intelligent” power line networks that make use of SCADA devices.U radu je opisan pregled širokopojasnog prijenosa podataka elektroenergetskom mrežom. Razvoj tehnologije prijenosa signala omogućio je prevladavanje problema prijenosa komunikacijskih signala putem elektroenergetske mreže. Time je omogućen širokopojasni prijenos podataka kojim se osigurava pristup Internetu koristeći postojeću infrastrukturu. Ovakva komunikacija dijeli se na: pristupnu i kućnu. Najveći ekonomski značaj ove tehnologije je mogućnost pružanja pristupa Internetu TCP/IP protokolom. Osim pristupa Internetu omogućava i implementaciju pametne elektroenergetske mreže (SCADA)

How COVID-19 lockdown has impacted demand curves of Croatia and the surrounding countries

Electrical energy is a specific commodity because it can’t be stored in significant quantities, so accurate day-ahead forecasting of total consumption plays a crucial role in stable operation of the whole power system. In order to maintain the adequacy, power generation and electricity consumption have to be constantly in a balance. Electricity demand curve is very sensitive and vulnerable to a lot of different factors that can be categorized in several main groups that include social, stochastic and weather dependent factors. In condition of global pandemic caused by COVID 19, prediction of total consumption is even more challenging task. New restrictive rules, that completely changed behavior of consumers, their daily routine and habits, have been adopted in most of the European countries. Hence, this lockdown restrictive measures affected the volume of electricity consumption and the shape of demand curves as well. This paper analyzes some of the cases with very variable electricity load, due to volatile households’ behavior, on cases of Croatia and countries in the region. Additionally, results are compared with the electricity load of Italy and Sweden whose economy and industry are well developed. Consumption of Sweden was interesting to observe because of its totally different approach of mitigating corona virus, without lockdown restrictions

An analysis of accidents in inland navigation in context of autonomous shipping

The collection of data on accidents in inland navigation is not mandatory in many European countries. The lack of a harmonized methodology or a centralized database of information on accidents makes it difficult to obtain a comprehensive picture of safety on European inland waterways. Consequently, the possibilities for improvement of technical standards are limited. The problem becomes particularly evident in light of the significant navigational challenges such as the introduction of autonomous shipping. Attempting to provide a better understanding of safety in inland navigation, the paper presents the results of an analysis of data on some 700 accidents which took place on the inland waterways in Austria and Serbia, over a 15-year period (2001/2002-2017). The analysis indicates the fundamental conditions in which it would be possible to reduce the human presence or even remove the crew from inland ships

Ispitivanje uticaja nekih imunosupresivnih faktora na pojavu kampilobakterioze živine

Campylobacteria are widely distributed in domestic and wild animals. Avian species are the most common host of campylobacteria, thus an important source for human infection caused by this organism. Campylobacteriosis in animals frequently proceeds without clinical symptoms, which may be due to the different virulence of the agent, as well as to the immune status of the infected animal. In this trial we investigated the effects of the vaccine against infective bursal disease (IBD) on occurrence and clinical manifestation of campylobacteriosis in conditions of controlled experimental infection with the strain Campylobacter jejuni. The immunosuppressive effects of a live attenuated vaccine against IBD on development of clinically manifest campylobacteriosis in perorally challenged chickens were assessed. The investigation was performed on 90 chickens in experimental conditions. The presence of Campylobacter jejuni was confirmed by reisolation, while identification of the organism was performed on the basis of its morphological, cultural and biochemical characteristics. Specific antibody titer and humoral immune response to C. jejuni specific antibodies were monitored using the complement fixation reaction method. Clinical symptoms of the disease were observed in chickens infected with Campylobacter jejuni and vaccinated against infective bursal disease. Pathomorphological findings revealed changes in the intestines and liver, from which Campylobacter jejuni was isolated. C. jejuni specific antibodies were detected in the infected birds in the third week post infection, with titer values ranging from 1:4 to 1:16. Results of our research strongly imply an immunosuppressive effect of the IBD vaccine on development of campylobacteriosis, which is supported by the clinical and morphological findings, i.e. isolation of the agent and detection of specific antibodies.Kampilobakterije su kod domaćih i divljih životinja široko rasprostranjeni mikroorganizmi, a živina je jedan od glavnih nosilaca kampilobakterija i važan izvor infekcija ljudi. Klinički simptomi kampilobakterioze kod živine se relativno retko javljaju, a razloge treba tražiti u različitoj virulenciji uzročnika i u imunološkom statusu inficiranih jedniki. U ovom radu je ispitivan uticaj vakcine protiv infektivnog burzitisa živine na nastanak i kliničku pojavu kampilobakterioze, posle veštačke infekcije terenskim sojem Campylobacter jejuni. Ispitivanje je izvršeno na 90 pilića u eksperimentalnim uslovima. Prisustvo Campylobacter jejuni u organizmu veštački inficiranih pilića dokazivano je reizolacijom uzročnika, a identifikacija izolovanih bakterija vršena je na osnovu njihovih morfoloških, kulturelnih i biohemijskih osobina. Prisustvo titra specifičnih antitela i kretanje humoralnog imunskog odgovora na antigene Campylobacter jejuni kod pilića u ogledu praćeno je primenom reakcije vezivanja komplementa (RVK). Kod pilića inficiranih sojem Campylobacter jejuni i imunizovanih vakcinom protiv infektivnog burzitisa uočeni su klinički znaci bolesti. Patomorfološkim ispitivanjem utvrđene su promene na crevima i jetri pilića iz kojih je izolovan Campylobacter jejuni. Specifična antitela za C. jejuni dokazana su kod inficiranih jedinki u trećoj nedelji od veštačke infekcije, a vrednosti njihovog titra su iznosile od 1:4 do 1:16. Rezultati ovih ispitivanja su potvrdili imunospresivno delovanje vakcine protiv infektivnog burzitisa koje je imalo za rezultat klinički manifestnu kampilobakteriozu. Infekcija je potvrđena na osnovu kliničkih simptoma i patomorfoloških promena, izolacijom uzročnika, kao i na osnovu vrednosti titra specifičnih antitela utvrđenih u uzorcima krvnih seruma oglednih pilića

Shallow-draught vessels for the Vessel Train

The Vessel Train is a novel semi-autonomous waterborne transport concept which implies a convoy of digitally connected vessels. Only the first vessel in the Vessel Train (the so-called “lead vessel”) is fully manned, while the remaining vessels (the so-called “following vessels”) are remotely controlled from the lead vessel and thus may sail either with a reduced crew or with the crew off-duty. The Vessel Train was the subject of the research project NOVIMAR (NOVel Iwt and MARitime transport concepts), funded by the European Commission within the framework of the Horizon 2020 program. One of the tasks of the project concerned the design of novel vessels for the Vessel Train. The Vessel Train ships were designed in compliance with a specific requirement: to utilize the horizontal (Ro-Ro) container handling. Additionally, two inland vessels had to fulfil another condition: to have as low design draught as possible, so as to provide for uninterrupted navigation even during the low-water periods which tend to be extended and more extreme on all major European inland waterways. Both the Ro-Ro handling of containers and the shallow draught considerably affect the ship general arrangement, cargo stowage and handling, structural strength, intact and damage stability, etc. Thus, this paper discusses the challenges encountered in design of large inland container Ro-Ro vessels with extremely shallow draughts, intended for the use in the Vessel Train

Nalaz specifičnih antitela protiv Leptospira interrogans u krvnom serumu goveda

U petogodišnjem periodu na području devet opština Južnobačkog regiona serološki je ispitano 24208 uzoraka krvnih seruma goveda, što čini 31,18 posto od ukupnog reproduktivnog fonda goveda. Uzorci su ispitani metodom mikroskopske aglutinacije, živim antigenima 9 serotipova leptospira: L. pomona, L. icterohaemorrhagiae, L. grippotyphosa, L. sejroe, L. tarassovi, L. australis, L. bataviae, L. canicola i L. hardjo. Specifična antitela protiv leptospira utvrđena su kod 286 ili 1,18 posto uzoraka seruma goveda. Nivo seroprevalencije infekcije izazvane leptospirama na godišnjem nivou bio je od 2,56 posto do 0,05 posto. Najveći broj seropozitivnih grla iznosio je 151 grlo, ili 3,54 posto i ustanovljen je u opštini Novi Sad. Tokom posmatranog perioda kod goveda je dijagnostikovano prisustvo četiri serotipa leptospira: L. pomona, L. icterohaemorrhagiae, L. grippotyphosa i L. hardjo. Najzastupljeniji serotip je L. hardjo 41,02 posto, dok su serotipovi L. grippotyphosa 34,61 posto, L. icterohaemorrhagiae 14,74 posto i L. pomona 9,61 posto dijagnostikovani u nižem procentu. Zapažen je trend porasta broja inficiranih grla leptospirama za 0,195 posto na godišnjem nivou. Na osnovu prikazane analize može da se predvidi sa verovatnoćom od 95 posto da će leptospiroza kod goveda za naredni period u Južnobačkom epizootiološkom području biti u intervalu od 0,09 posto do 3,50 posto.Serological investigations were performed on 24,208 samples of cattle blood serum, representing 31.18% of the reproductive cattle fund in the teritory of nine municipalities in the Southern Backa region over a period of five years. The samples were examined using the method of microscopic agglutination, with live antigens of nine leptospira serotypes: L.pomona, L.icterohaemorrhagiae, L.grippotyphosa, L.sejroe, L.tarassovi, L.australis, L.bataviae, L.canicola, and L.hardjo. Specific antibodies against leptospira were established in 286 or 1.18% samples of cattle serum. The level of seroprevalence of leptospira infection at an annual level ranged from 2.56% to 0.05%. The biggest number of seropositive cattle were registered in the municipality of Novi Sad – 151 cattle, or 3.54%. In the course of the observation period, the presence of four serotypes of leptospira were diagnozed in catle: L.pomona, L.icterohaemorrhagiae, L.grippotyphosa, L.hardjo. The most represented serotype was L.hardjo, 41.02%, while the serotypes L.grippotyphosa (34.61%), L.icterohaemorrhagiae (14.74%) and L.pomona (9.61%) were diagnozed in smaller percentages. An increasing tendency was observed in the number of cattle infected with leptospira at an annual level of 0.195%. On the basis of the presented analysis, it can be predicted with a probability of 95%, that leptospirosis in cattle will appear within the range of 0.09% to 3.50% in the epizootiological region of Southern Backa in the coming period

Modelling of fuel in the nuclear reactor using the ANSYS code

Iako se gorivni elementi razlikuju od reaktora do reaktora, gorivna šipka je približno jednaka za svaki tip. Sastoji se od obloge koju čini cijev od cirkonijeve legure, a punjena je gorivnim tabletama. Između goriva i obloge je zazor ispunjen helijem. Gorivna šipka čini prvu barijeru za obranu od širenja radioaktivnosti, stoga se velika pažnja pridaje sigurnosnima analizama u svrhu očuvanja njezina integriteta. Zato je potrebno stalno odvoditi toplinu kako ne bi došlo do širenja radioaktivnosti uslijed oksidacije i oštećenja košuljice . Temperaturna analiza napravljena je u programu ANSYS gdje je pokazano da se u normalnim uvjetima u pogonu temperatura u gorivu i košuljici ne približava kritičnim vrijednostima.Despite the fact that the design of the fuel assembley depends of the reactor type, design of their fuel rods is more or less the same. It consists of cladding tube into which fuel pellets are inserted. Between cladding and the fuel pelletes, there is helium gap. Fuel rod also presents first barrier in defence against radioactivity releas, therefore, it is very importatnt to carry out security analsys in order to preserve its integrity. In order to prevent cladding and fuel melt which leads to radioactivity releas, it is crucial to continuously cool the fuel rods. Temperature distribution analysis in ANSYS shows that under normal operating conditions, temperatures in cladding tube and fuel are not close to critical values

Passive safety containment systems in the nuclear power plant

Porast tlaka za vrijeme teške nesreće predstavlja jedan od glavnih problema po pitanju sigurnosti nuklearne elektrane. Sustavi za odzračivanje kontejnmenta i kontolirano ispuštanje plinova kroz filtre ( eng.conteinment filter venting system CFVS) osmišljeni su upravo s ciljem rjšavanja tog gorućeg problema. U uvjetima teške nesreće najučinkovitijim su se pokazali pasivni sustavi (PCFV) koji za svoj rad ne trebaju električnu energiju, intervenciju operatera kao ni pomoćne sustave. Pokreću se samostalno, pucanjem rupture diska na određenom tlaku, a glavna zadaća uz snižavanje tlaka im je filtiranje zraka prije otpusta u atmosferu. Postoje različite metode filtracije, čija je premjerna zadaća eliminacija organskog i elementarnog joda te aerosola. Kako bi se osigurala iznimna efikasnost filtriranja, postupak se provodi u više koraka. Rapidan porast tlaka mogu izazvati eksplozije smjese plinova poput vodika i ugljičnog monoksida, pa je jedan od ključnih postupaka pri očuvanju integriteta kontejnmneta zadržavanje njihove koncentracije na niskoj razini. To se postiže pasivnim autokatalitičkim rekombinatorima (PAR) koji kemijskom reakcijom između vodika / ugljičnog monoksida i kisika oslobađaju toplinu uz nastanak vodene pare.Pressure increas during severe accidents is one of the major problems of nuclear power plant safety. Containment filter venting systems are designed in order to deal with such issue by reducng pressure build-up in containment. In severe accidents conditions, passive containment filtered venting systems (PCFV) have been shown as the most effective, while they have no need for electrical power, operator intervention or any other support system. They are activated independently by bursting rupture disc if containment pressure reachs certain set point and besides decreasing pressure their main goal is to filter contaminated venting gas flow before its release in the atmosphere. There are few different filter venting sytems whose main purpose is to retain radioactive aerosols and fission products such as iodine (both elemental and organic) from venting gas. In order to ensure exceptional filtration efficiency, the process is carried out in several steps. Rapid pressurization of containment can be also caused by explosions of gas mixtures such as hydrogen and carbon monoxide, so one of key procedures for preserving containment itegrity is to keep their concentration low. This is achieved by passive autocatalytic recombiner (PAR) which, by chemical reaction between hydrogen / carbon monoxide and oxygen release heat with formation of aerated watter

Passive safety containment systems in the nuclear power plant

Porast tlaka za vrijeme teške nesreće predstavlja jedan od glavnih problema po pitanju sigurnosti nuklearne elektrane. Sustavi za odzračivanje kontejnmenta i kontolirano ispuštanje plinova kroz filtre ( eng.conteinment filter venting system CFVS) osmišljeni su upravo s ciljem rjšavanja tog gorućeg problema. U uvjetima teške nesreće najučinkovitijim su se pokazali pasivni sustavi (PCFV) koji za svoj rad ne trebaju električnu energiju, intervenciju operatera kao ni pomoćne sustave. Pokreću se samostalno, pucanjem rupture diska na određenom tlaku, a glavna zadaća uz snižavanje tlaka im je filtiranje zraka prije otpusta u atmosferu. Postoje različite metode filtracije, čija je premjerna zadaća eliminacija organskog i elementarnog joda te aerosola. Kako bi se osigurala iznimna efikasnost filtriranja, postupak se provodi u više koraka. Rapidan porast tlaka mogu izazvati eksplozije smjese plinova poput vodika i ugljičnog monoksida, pa je jedan od ključnih postupaka pri očuvanju integriteta kontejnmneta zadržavanje njihove koncentracije na niskoj razini. To se postiže pasivnim autokatalitičkim rekombinatorima (PAR) koji kemijskom reakcijom između vodika / ugljičnog monoksida i kisika oslobađaju toplinu uz nastanak vodene pare.Pressure increas during severe accidents is one of the major problems of nuclear power plant safety. Containment filter venting systems are designed in order to deal with such issue by reducng pressure build-up in containment. In severe accidents conditions, passive containment filtered venting systems (PCFV) have been shown as the most effective, while they have no need for electrical power, operator intervention or any other support system. They are activated independently by bursting rupture disc if containment pressure reachs certain set point and besides decreasing pressure their main goal is to filter contaminated venting gas flow before its release in the atmosphere. There are few different filter venting sytems whose main purpose is to retain radioactive aerosols and fission products such as iodine (both elemental and organic) from venting gas. In order to ensure exceptional filtration efficiency, the process is carried out in several steps. Rapid pressurization of containment can be also caused by explosions of gas mixtures such as hydrogen and carbon monoxide, so one of key procedures for preserving containment itegrity is to keep their concentration low. This is achieved by passive autocatalytic recombiner (PAR) which, by chemical reaction between hydrogen / carbon monoxide and oxygen release heat with formation of aerated watter

Passive safety containment systems in the nuclear power plant

Porast tlaka za vrijeme teške nesreće predstavlja jedan od glavnih problema po pitanju sigurnosti nuklearne elektrane. Sustavi za odzračivanje kontejnmenta i kontolirano ispuštanje plinova kroz filtre ( eng.conteinment filter venting system CFVS) osmišljeni su upravo s ciljem rjšavanja tog gorućeg problema. U uvjetima teške nesreće najučinkovitijim su se pokazali pasivni sustavi (PCFV) koji za svoj rad ne trebaju električnu energiju, intervenciju operatera kao ni pomoćne sustave. Pokreću se samostalno, pucanjem rupture diska na određenom tlaku, a glavna zadaća uz snižavanje tlaka im je filtiranje zraka prije otpusta u atmosferu. Postoje različite metode filtracije, čija je premjerna zadaća eliminacija organskog i elementarnog joda te aerosola. Kako bi se osigurala iznimna efikasnost filtriranja, postupak se provodi u više koraka. Rapidan porast tlaka mogu izazvati eksplozije smjese plinova poput vodika i ugljičnog monoksida, pa je jedan od ključnih postupaka pri očuvanju integriteta kontejnmneta zadržavanje njihove koncentracije na niskoj razini. To se postiže pasivnim autokatalitičkim rekombinatorima (PAR) koji kemijskom reakcijom između vodika / ugljičnog monoksida i kisika oslobađaju toplinu uz nastanak vodene pare.Pressure increas during severe accidents is one of the major problems of nuclear power plant safety. Containment filter venting systems are designed in order to deal with such issue by reducng pressure build-up in containment. In severe accidents conditions, passive containment filtered venting systems (PCFV) have been shown as the most effective, while they have no need for electrical power, operator intervention or any other support system. They are activated independently by bursting rupture disc if containment pressure reachs certain set point and besides decreasing pressure their main goal is to filter contaminated venting gas flow before its release in the atmosphere. There are few different filter venting sytems whose main purpose is to retain radioactive aerosols and fission products such as iodine (both elemental and organic) from venting gas. In order to ensure exceptional filtration efficiency, the process is carried out in several steps. Rapid pressurization of containment can be also caused by explosions of gas mixtures such as hydrogen and carbon monoxide, so one of key procedures for preserving containment itegrity is to keep their concentration low. This is achieved by passive autocatalytic recombiner (PAR) which, by chemical reaction between hydrogen / carbon monoxide and oxygen release heat with formation of aerated watter