Visualizations of Gaussian and Mean Curvatures by Using Mathematica

U radu je dan prikaz programa, pisanog u jeziku Mathematica, koji omogućuje bojanje plohe bojom koja je funkcija njene Gaussove ili srednje zakrivljenosti kao i crtanje grafova tih funkcija. Dano je deset primjera vizualizacija dobivenih pomoću tog programa. Članak je mali ulomak iz studentskog rada [7] koji je 2004. godine nagrađen Rektorovom nagradom.The paper gives an overview of the program written in the language Mathematica, which enables colouring of a surface with the colour that is the function of its Gaussian and mean curvatures, as well as drawing the graphs of those functions. Ten examples of visualizations obtained by the use of that program are presented. The article is a small extract from the students\u27 paper which was awarded Rector\u27s Prize in 2004

So you bought your diploma? Private education in Croatia in the context of post-communism

Following the Homeland War and fall of the communist regime new private higher education institutions sprouted along Croatia and Eastern Europe. While accepted by governments in their inception and often incentivized in their establishment they are yet to be completely accepted by the public. In order to better understand their struggle for legitimacy a survey was issued to the Croatian public to learn what does it seek in a 'good university'. The Kano model was used to survey 67 participants using convenience sampling in various locations of the countries capital. Results show a consensus on what are the fundamental requirements for the institution but differ on what will enhance their performance and make them attractive. A clear path can be structured to appease the diverse groups that arose

So you bought your diploma? Private education in Croatia in the context of post-communism

Following the Homeland War and fall of the communist regime new private higher education institutions sprouted along Croatia and Eastern Europe. While accepted by governments in their inception and often incentivized in their establishment they are yet to be completely accepted by the public. In order to better understand their struggle for legitimacy a survey was issued to the Croatian public to learn what does it seek in a 'good university'. The Kano model was used to survey 67 participants using convenience sampling in various locations of the countries capital. Results show a consensus on what are the fundamental requirements for the institution but differ on what will enhance their performance and make them attractive. A clear path can be structured to appease the diverse groups that arose

PRIMJENA „EINSTEINOVE ZAGONETKE“ PRI RJEŠAVANJU PROBLEMA ALOKACIJE GRAĐEVINSKIH STROJEVA

“Einstein’s riddle” is a popular example of constraints satisfaction problem. Since its introduction, different forms and variations of the riddle have been presented. Regardless of the variant of the riddle, its solution is considered a tough challenge for humans. Researchers have developed and are still developing mathematical models, as well as computational simulation models for solving it. In this article, the authors have modified a previously published mathematical model and developed a computational spreadsheet model for solving the riddle, which provides a unique solution for the riddle. The model was also tested in a small and medium-scaled form for solving constraint satisfaction problems regarding the allocation of construction machines. The authors have also highlighted the model’s limitations for solving such problems and made suggestions regarding necessary modifications in the model to solve more complex problems in the same domain.„Einsteinova zagonetka“ je prepoznatljiv primjer kombinatornog problema ispunjenja ograničenja. Ova zagonetka je imala više verzija, no bez obzira na formulaciju, uglavnom se smatra vrlo teškim zadatkom. Znanstvenici su razvijali i dalje razvijaju matematičke modele, a potom i računalne simulacijske modele za rješavanje spomenutog problema. Autori su u ovome radu modificirali ranije predstavljeni matematički model, a potom prema njemu izradili računalni model, koristeći se proračunskim tablicama kako bi riješili zagonetku. Model je ponudio jedinstveno rješenje u vrlo kratkom vremenu, a potom je ispitan pri rješavanju sličnog problema u građevinskoj praksi. Istaknuta su ograničenja u primjeni modela u obliku kojim je riješena „Einstenova zagonetka“ te koje su modifikacije nužne za aplikaciju pri rješavanju kompleksnijih problema u istoj domeni

PREGLED DOSTIGNUĆA PRIMJENE BIM KONCEPTA U HRVATSKOJ, ČEŠKOJ, NJEMAČKOJ I SLOVENIJI

Building information modelling (BIM) may currently be considered the fastest developing concept in the field of construction management, aiming to become a global standard. Although the roots of the concept date back to the mid-1970s, some original expectations are still missing from its implementation. There has been a time gap between its theoretical and practical implementations. While the simultaneous development of information technologies is one reason for the implementation delay, other reasons remain unclear. This paper analyzes the gaps between theoretical and practical BIM application, as well as the legislation regarding BIM implementation in four countries (in alphabetical order: Croatia, the Czech Republic, Germany, and Slovenia). The paper additionally presents a survey of current practical BIM applications as well as general and theoretical feedback from construction projects that implemented BIM.Jedan od najbrže razvijajućih koncepata u domeni metoda i alata za upravljanje građevinskim projektima, uz konačni cilj da postane globalni standard, je informacijsko modeliranje građevina, tj. BIM. Iako se koncept razvija od sredine 1970-ih, neka od originalnih očekivanja u njegovoj primjeni i danas nedostaju. Očito je da postoji vremensko odstojanje između njegove teorijske i praktične primjene. Istovremeno, razvijanje nužnih alata informacijske tehnologije je jedan od razloga zašto praktična primjena zaostaje, no ostali razlozi su još nejasni. U ovome radu autori analiziraju razlike između teoretske i praktične primjene BIM-a u zemljama odakle dolaze (Hrvatske, Češke, Njemačke i Slovenije). Rad predstavlja pregled trenutačnih dostignuća primjene BIM-a te povratnih informacija s projekata na kojima je BIM primijenjen

Development of a new and modification of existing elastic clips for rails fastening

Jedan od problema sustava za pričvršćenje tračnica na podlogu (sustav pričvršćenja) koji se javlja s razvojem željeznica jest oštećenje elastičnih pritiskalica, čime se gubi konstrukcijski integritet između tračnice i podloge. Stoga postoji potreba za razvojem novih ili poboljšanjem postojećih pritiskalica. U radu je kroz dosadašnja istraživanja opisan doprinos i uloga pojedinih komponenata sustava pričvršćenja pri djelovanju raznih slučajeva opterećenja, a kao alatu čijom se promjenom parametara može utjecati na učinkovitost sustava pričvršćenja, posebno je usmjereno na pritiskalice. Detaljno je opisan postupak izrade numeričkih modela kojima je moguće provođenje parametarskih analiza za razvoj novih ili modifikaciju postojećih pritiskalica za pričvršćenje tračnica.One of the problems of railway fastening systems (fastening system) that occurs due to the development of railways is the damage of the elastic clips, which leads to the loss of structural integrity between the rail and the base. Therefore, there is a need to develop new clips or improve existing ones. The paper describes the contribution and role of each component of the fastening system in different loading cases. As a tool whose parameters can affect the efficiency of the fastening system, special attention is given to the clips. Finally, an example is briefly described for creating numerical models that can be used to perform parametric analyses in order to develop new clips or improve existing ones

Seismic risk for Croatia: overview of research activities and present assessments with guidelines for the future

Iz pozicije glavnog izvršitelja za procjene rizika od potresa za Hrvatsku, napravljen je pregled brojnih i metodološki različitih procjena rizika, uključujući nepovezane pojedinačne inicijative. Cilj rada je pozicionirati i osvrnuti se na doprinose svake od procjena, ali i upozoriti na manjkavosti odnosno ograničenja. Opisana je i uobičajena metodologija analizirajući svaki od faktora seizmičkog rizika, dajući pregled sadašnjeg stanja istraživanja u Hrvatskoj i u svijetu te nudeći smjernice za daljnje strateško djelovanje jer svi postojeći rezultati ističu potres kao neprihvatljiv rizik za Hrvatsku.An overview of numerous methodologically different risk assessments, including sporadic individual initiatives, is presented from the perspective of a leading expert for earthquake risk assessments for Croatia. The aim of the paper is to evaluate and discuss contributions of each of the assessments, but also to caution about their deficiencies i.e. limitations. A common methodology for estimating seismic risk is described by analysing each of its factors, by providing an overview of current research in Croatia and worldwide, and by offering guidelines for further strategic actions, as all existing results reveal that earthquake is an unacceptable risk for Croatia

Bioconjugate of Lysozyme and the Antibacterial Marine Sesquiterpene Quinone Avarone and Its Derivatives

A conjugate of lysozyme with avarone, a bioactive sesquiterpene quinone of marine origin, and its three derivatives were synthesized. MALDI TOF mass spectral analysis and tryptic digestion showed that the only residue in lysozyme that was modified by all derivatives was lysine 97. The identity of the residue was in full correlation with the prediction obtained by molecular modeling. All bioconjugates preserved most of the enzymatic activity of lysozyme. The melting point of the conjugates was slightly increased in comparison to lysozyme, indicating a slight stabilization of structure. The antibacterial activity of all the conjugates to both Gram positive and Gram negative bacteria was stronger than the activity of either lysozyme or the quinones, the MIC values being in low micromolar range for some conjugates.This is the peer-reviewed version of the article: Novaković, I., Anđelković, U., Zlatović, M., Gašić, M.J., Sladić, D., 2012. Bioconjugate of Lysozyme and the Antibacterial Marine Sesquiterpene Quinone Avarone and Its Derivatives. Bioconjugate Chem. 23, 57–65. [https://doi.org/10.1021/bc200330m

Post-earthquake damage assessment of buildings – procedure for conducting building inspections

Procjene oštećenja i uporabljivosti građevina u Hrvatskoj, iskočile su u prvi plan nakon potresa u Zagrebu 22. ožujka 2020. S obzirom na manjkavosti pripremne faze, pri čemu nije provedena edukacija stručnjaka prije potresa, nego u hodu, procjene su sadržavale dozu subjektivnosti i interpretacije na temelju znanja, iskustva, ali i intuicije pojedinaca. U radu je detaljno prikazana metodologija koja može pomoći u brzim procjenama te kod detaljnih inženjerskih pregleda koji se moraju napraviti prije obnove. Prikazana metodologija se može iskoristiti u slučaju novoga razornog potresa koji se može dogoditi već sutra.Assessments of building damage and usability were of primary importance after the Zagreb earthquake of 22 March 2020. Due to deficiencies of preparatory phase, where education of experts was not carried out before the earthquake, but later on, the assessments contained certain subjectivity and interpretations, based on knowledge and experience, but also on intuition of individuals. Detailed methodology, which should improve rapid assessments and detailed engineering inspections to be performed before reconstruction, is highlighted in the paper. This methodology may be utilized if another devastating earthquake occurs, which could happen already tomorrow

Zagreb earthquake of 22 March 2020 – preliminary report on seismologic aspects and damage to buildings

U radu su opisane bitne značajke i glavne posljedice potresa magnitude 5,5 koji je u jeku pandemije virusa COVID-19 zadesio Zagreb i okolicu. Premda je potres, seizmološki gledano, bio umjerene magnitude, prouzročio je gubitak jednoga života i veliku materijalnu štetu. Napravljen je pregled stanja prije trešnje te prikaz lokacije, seizmičke aktivnosti i organizacije pregleda zgrada. Grubo su razvrstani podaci o oštećenjima, s težištem na povijesnoj jezgri i četvrtima blizu epicentra. Na kraju su istaknute nužne aktivnosti koje je odavno trebalo provesti, s nadom da će ih ovaj potres potaknuti.Significant characteristics and main consequences of the 5.5 magnitude earthquake that struck Zagreb and its surroundings in the midst of the COVID-19 pandemic are presented in the paper. Although, from the seismologic aspect, the earthquake was of moderate magnitude, it caused the loss of one life and considerable material damage. An overview of the situation before the quake is given, and information about the location, seismic activity, and organisation of building inspection activity, is presented. The data on damage are roughly classified, with the focus on historic core of the city and districts situated close to the epicentre. A strong emphasis is placed on indispensable activities that should have been carried out a long time ago, in the hope that they will be prompted by this earthquake