Primjene vrijednosti retencijskih sila CEKA ankera

Retention o f a partial denture is the resistance of retaining elements to forces which endeavour to dislodge it from its base. Basic retention is obtained by means o f clasps, attachments, diaphragms, telescopic crowns, magnets etc. The aim of the present study was to determine the dynamics o f reduced retention forces in CEKA attachments (OL 694). An instrument, especially constructed for the purpose, was used to measure retention forces, and the test was carried out with and without the addition o f saliva. The results of the study, which are presented graphically and in tables, and described by exponential law, show that at the commencement o f the test the value of retention force in the attachment, without the addition o f saliva, amounted to approximately 10.2 N, and after 1200 cycles o f insertion and removal, 3.4 N. With the addition o f saliva the retention force o f the attachment amounted to 9.92 N at the commencement o f the test and after 1200 cycles o f insertion and removal, 5.12 N. A fundamental factor which has a cardinal effect on the extent of the retention force is wear and fatigue o f the material. Although in this study no significant differences in the reduction o f retention fo rces were found than had been anticipated, it is recommended that special attention should be paid to the choice of retention technique in partial dentures.Retencija djelomične proteze jest otpor retencijskih elemenata silama koje je nastoje pomaknuti s ležišta. Osnovna retencija dobiva se s pomoću kvačica, ankera, prečki, teleskop krunica, magneta i dr. Ovim radom nastojala se utvrditi dinamika smanjenja retetncijske sile kod CEKA ankera (OL 694), Ispitivalo se je s pomoću aparature za mjerenje retencijske sile, koja je konstruirana u tu svrhu. Ispitivanje je rađeno s nazočnošću sline i bez nje. Rezultati istraživanja - koji su prikazanai grafički i tablicama, a opisani eksponencijslnim zakonom - pokazuju da je vrijednost retencijske sile kod etečmena bez nazočnosti sline na početku ispitivanja iznosila prosječno 10.2 N. Nakon 1200 ciklusa stavljanja i vađenja, izmjerena je sila 3,4 N. Promjena retencijske sile etečmena s nazočnošću sline iznosila je od početnih 9,92 N do 5,12 N nakon 1200 ciklusa stavljanja i vađenja. Čimbenik koji bitno utječe na veličinu retencijske sile jest trošenje i zamor materijala. Iako u ovom istraživanju nisu vidljive velike razlike u opadanju retencijskih sila od pretpostavljenih, može se preporučiti posebna pozornost izboru načina retencije djelomične proteze

Analysis of beach nourishment and construction in Croatia

Plaže istočne obale Jadrana čine temelj turističke ponude Hrvatske, ali su pod iznimnim pritiskom turizma i klimatskih promjena. Za upravljanje obalom potrebni su podatci, a zasad izostaje i nacionalna strategija. Podatci o plažama prikupljeni su iz regionalnih programa svake županije, potom su prikupljeni podatci o postupku dohranjivanja obale putem ankete jedinica lokalne samouprave, a posebno su i analizirane snimke iz zraka za podatke o nasipavanju (tj. izgradnji) obale. Hrvatska ima 1904 pretežito male šljunčane plaže, provodi dohranu svake druge godine u malim količinama, a ujedno je i nasipala 27 % nove površine, sve pretežito za potrebe plaža, luka i turizma.Beaches on the eastern Adriatic coast are the basis of Croatia’s tourism offering while also being under pressure from climate change. Data is necessary to manage beaches effectively, but data is lacking as well as the long awaited national strategy for coastal management. This paper collected data about beaches from regional documents, nourishment data was obtained by survey from local municipalities while beach construction data was obtained from aerial photogrammetry. Croatia has more than 1904 small gravel beaches and nourishment is performed in small increments beinnaly, while more than 27 % of existing beach area has been constructed all primarily for the needs of beaches, marines and tourism