Determination of optimal reversed field with maximal electrocaloric cooling by a direct entropy analysis

Application of a negative field on a positively poled ferroelectric sample can enhance the electrocaloric cooling and appears as a promising method to optimize the electrocaloric cycle. Experimental measurements show that the maximal cooling does not appear at the zero-polarization point, but around the shoulder of the P-E loop. This phenomenon cannot be explained by the theory based on the constant total entropy assumption under adiabatic condition. In fact, adiabatic condition does not imply constant total entropy when irreversibility is involved. A direct entropy analysis approach based on work loss is proposed in this work, which takes the entropy contribution of the irreversible process into account. The optimal reversed field determined by this approach agrees with the experimental observations. This study signifies the importance of considering the irreversible process in the electrocaloric cycles

The Association Between Morphology, Speed, Power and Agility in Young Tennis Players

The aim of this study was to investigate the correlation of anthropometric variables and motor abilities in change of direction speed and reactive agility performance in young tennis players. 50 tennis players (age 12.3 ± 1.2 years, height 156.7 ± 12.8 cm, body mass 45.9 ± 8.9 kg), who were ranked within the top 50 ranking places of the National Tennis Association, as well as within the top 300 on the international "Tennis Europe" rankings, participated in the study. The sample of anthropometric variables in this study comprised the measurement of participant height, body mass, body mass index and percentage of body fat. Also, participants performed tests assessing speed (5, 10, and 20 m sprints), agility (20 yards, 4x10 yards, T–test, TENCODS, and TENRAG), and explosive power (countermovement jump, single-leg countermovement jump, squat jump, standing long jump and single-leg triple jump). The results showed that there is a statistically significant correlation of agility with anthropometric characteristics, running speed tests and horizontal explosive power variables, whereas there was no significant correlation with vertical explosive power variables. In conclusion, the results of this research confirmed the hypothesis that there is a significant correlation in almost all anthropometric variables and motor abilities in change of direction speed and reactive agility performance in young tennis players. Thus, our findings provide useful information for coaches to create a wide range of tennis-specific exercises to develop performance, especially in a players neuromuscular fitness

Which education model for the Armed Forces and National Security to choose – Can Croatia learn from Portugal?

This paper seeks to answer whether the concept development of education for the Croatian Armed Forces and national security may learn from Portuguese experience. By doing so, it reviewed theoretical notions of defence and security studies, contemporary concepts in education for the armed forces and national security, and it offered a case study of Portugal in this field. The current objectives of the national security in Croatia, as defined in National Security Strategy 2017, point towards the need of establishing an adequate education system, at the state level. The paper offers contemporary Portuguese experience as a potential example for implementation in Croatia

Hepatalna adenomatoza - prikaz rijetke indikacije za transplantaciju jetre

The most successful treatment option for end-stage liver failure is liver transplantation. Cirrhosis, acute liver failure, and liver cancer are the most common reasons for liver transplantation. Croatia is a member of the Eurotransplant program and performs more than 100 liver transplants annually.Transplantacija jetre je trenutno najuspješniji modalitet liječenja jetrenih bolesti u završnom stadiju. Najčešće indikacije za transplantaciju jetre su ireverzibilno zatajenje jetre uzrokovano cirozom, akutno fulminantno zatajenje te karcinom jetre. Republika Hrvatska je uspješna članica Eurotransplant programa, a godišnje se provede više od 100 transplantacija jetre

Europski demos - Postoji li politička potpora Europskoj uniji nakon pristupanja Republike Hrvatske?

Rad se bavi pitanjem postojanja europskog demosa i s tim povezane političke potpore Europskoj uniji nakon ulaska posljednje države članice, Republike Hrvatske, u ljeto 2013. godine. Konceptualni okvir koji nudi predstavlja kombinaciju teorijskih pretpostavki Davida Eastona i Dietera Fuchsa o difuznoj potpori političkoj zajednici i režimu. Metoda analize i prikupljanja podataka je kvantitativna metoda utemeljena na nalazima standardnih Eurobarometara, a vremenski okvir na koje se istraživanje referira obuhvaća nalaze Eurobarometra nakon ulaska posljednje članice u EU-a do danas. Na kraju rada donosi se kratka rasprava o nalazima istraživanja te se nudi adekvatan zaključak

Analiza županija u Republici Hrvatskoj - povijest, demografija, gospodarstvo

Uspostava sadašnjeg sustava lokalne samouprave u Republici Hrvatskoj započela je 1992. godine postavljanjem temeljnog zakonodavnog okvira. Sustav je uspostavljen 1993. godine, a oživotvoren je provedbom prvih lokalnih izbora. U Republici Hrvatskoj ustrojeno je ukupno 555 jedinica lokalne samouprave i to: 428 općina, 127 gradova, te 20 jedinica područne (regionalne) samouprave, odnosno županija. Grad Zagreb, kao glavni grad Republike Hrvatske, ima poseban status grada i županije, tako da je u Republici Hrvatskoj sveukupno 576 jedinica lokalne i regionalne samouprave. Današnji ustroj jedinica lokalne i regionalne samouprave i uprave postoji 22 godine i utemeljen je u specifičnim društvenim, političkim i gospodarskim uvjetima. Taj okvir je danas promijenjen, a to utječe i na svrsishodno funkcioniranje ovoga sustava. Velike su razlike među županijama, općinama i gradovima. One se očituju u demografskim, gospodarskim, organizacijskim i ljudskim disproporcijama. Potrebno je povećati regionalnu konkurentnost županija. Analiza regionalne konkurentnosti omogućava uvid i praćenje napredovanja ili zaostajanja pojedine županije ili regije kao i njezinu sposobnost u „hvatanju koraka“ s razvijenijima od sebe.The establishment of the current system of local government in the Republic of Croatia started in 1992 by bringing the basic legislative framework. The system was established in 1993, and was implemented through the implementation of the first local elections. In Croatia there are a total of 555 local governments: 428 municipalities, 127 cities and 20 district (regional) governments, or counties. City of Zagreb as Croatian capital, has a special status of the city and county, so that in the Republic of Croatia there are total of 576 local and regional governments. The structure of local and regional self-government exists 23 years and is based in specific social, political and economic conditions. This framework has now changed and that affects the practical functioning of this system. There are great differences between counties, municipalities and towns. They are reflected in the demographic, economic, organizational and human disproportion. It is necessary to increase regional competitiveness of counties. Analysis of regional competitiveness will offer insight and tracking progress or falling behind individual counties or regions as well as its ability to "catch up" with developed than themselves

Electric-field-temperature phase diagram of the ferroelectric relaxor system (1-x)Bi1/2Na1/2TiO3-xBaTiO3 doped with manganese

The electric-field-temperature phase diagram for the lead-free relaxor material (1 - x)(Bi1/2Na1/2)TiO3 - xBaTiO 3 (x = 0.03, 0.06, and 0.09) doped with 0.5 mol% Mn (BNT-100xBT:Mn) was established. Transition lines between ergodic or nonergodic relaxor states and the field-induced ferroelectric state were determined at constant temperatures with electric-field-dependent measurements of the polarization as well as of the piezoelectric coefficient and permittivity. Near the depolarization temperature Td, the switching between two ferroelectric poling directions occurs in two steps via an intermediate relaxor state. This effect is closely related to the pinching of the ferroelectric hysteresis loop.open2