ROCK MASS DAMAGED ZONE CAUSED BY BLASTING DURING TUNNEL EXCAVATION

Izrada podzemnih rudničkih prostorija, tunela i odlagališta radioaktivnog otpada, podrazumijevaju primjenu jednakih odnosno sličnih tehnologija. Uslijed iskopa tunela miniranjem dolazi do određenog stupnja oštećenja stijenske mase oko konture presjeka iskopa. Oštećenja stijenske mase koja nastaju u neposrednoj okolini konture presjeka tunela izražene su proširenjem postojećih i stvaranjem novih pukotina, odnosno promjenom fizičko-mehaničkih svojstava stijenske mase. Prilikom izrade dubokih geoloških odlagališta radioaktivnog otpada zahtjevi po pitanju što manjeg oštećivanja stijene su jednaki ili veći u odnosu na tunele. Opisana istraživanja usmjerena su određivanju dubine zone oštećenja nastale miniranjem. Dubina zone oštećenja određivana je mjerenjem promjena fizičko-mehaničkih svojstava stijenske mase oko konture iskopa tunela. Istraživanjem su parametri bušenja i miniranja uspoređeni s dubinom i veličinom prostiranja oštećenja.Design of underground spaces, including tunnels, and repositories for radioactive waste include the application of the same or similar technologies. Tunnel excavation by blasting inevitably results in the damage in the rock mass around the excavation profile. The damage in the rock mass immediately next to the tunnel profile emerges as the expanding of the existing cracks and the appearance of new cracks, i.e. as the change of the physical and-mechanical properties of the rock mass. Concerning the design of deep geological repositories, requirements in terms of damaged rock are the same or more rigorous than for the design of tunnel. The aforementioned research is directed towards determining the depth of damage zone caused by blasting. The depth of the damage zone is determined by measuring the changes of physical and-mechanical properties of the rock mass around the tunnel excavation profile. By this research the drilling and blasting parameters were correlated with the depth and size of the damage zone

EFFECTS OF TWO DIFFERENT TRAINING PROGRAMS ON THE SIT-UP TEST IN THE SEVENTH GRADE ELEMENTARY SCHOOL STUDENTS

Na nastavi TZK jedan od testova za provjeravanje motorièkih sposobnosti je podizanje trupa iz ležanja u sjed. Navedenim testom se provjerava repetitivna jakost trupa uèenika. Cilj je bio usporediti efikasnost dviju vrsta treninga: stabilizacijskih vježbi i pregiba trupa na test podizanje trupa iz ležanja u sjed kod uèenika sedmih razreda osnovne škole. Uzorak ispitanika saèinjavalo je 47 uèenika sedmih razreda osnovne škole. Razredi su sluèajnim odabirom podijeljeni na kontrolnu skupinu, koji su radili na tehnici trèanja (n=14), eksperimentalnu skupinu koja je provodila pregibe trupa (TRB, n=16) i eksperimentalnu skupinu koja je provodila stabilizacijske vježbe (STAB, n=17). Trenažni proces se odvijao u periodu od 6 tjedana. U tom periodu je provedeno 10 sati nastave TZK-a. Mjerenje je izvršeno na poèetku i nakon 6 tjedana trenažnog procesa. Prosjeèna razlika izmeðu rezultata u inicijalnom i finalnom mjerenju bila je najveæa kod uèenika koji su provodili dopunski trening stabilizacijskih vježbi (d=4,53), nešto manja kod kojima su sadržaj dopunskog treninga bile vježbe pregiba trupa (d=3,56), a najmanja kod uèenika u kontrolnoj grupi (0,29). Kod obje eksperimentalne skupine razlika izmeðu aritmetièke sredine u inicijalnom i finalnom stanju bila je statistièki znaèajna, dok kod uèenika kontrolne skupine navedena razlika nije dosegla razinu statistièke znaèajnosti. Stabilizacijske vježbe i pregibi trupa efikasno razvijaju repetitivnu jakost mišiæa prednje i boène strane trupa. Jakost mišiæa trupa bilo bi preporuèljivo razvijati stabilizacijskim vježbama, jer omoguæuju efikasno poboljšanje jakosti mišiæa trupa bez dugoroèno štetnih posljedica na kralježnicu.Sit-up tests are used for measuring muscular endurance at physical education class. The aim of the study was to compare the efficiency of two types of the training process: core stabilization exercises and traditional trunk exercises on the sit-up test performed by the seventh grade elementary students. Sixty students began with the participation in the experimental program, and forty seven of them (age 13,7 ± 0,3 years, height 161.6 cm ± 7.01 cm, weight 52.55 kg ± 11.73 kg) completed the program. The classes were randomly divided into a control group which worked on a running technique (RTE) (N=14), an experimental group which performed traditional trunk exercises (TTE, N=16) and another experimental group which performed core stabilization exercizes (CSE, N=17). The training process lasted for six weeks. During that period physical education classes were held ten times. The initial measurement was done a week before the beginning of the treatment, and the final measurement a week after finishing the treatment. The average difference between the results in the initial and final measurement was greatest with the students who performed the additional training of core stabilization exercises (d=4.53), somewhat smaller with those who performed the additional training of traditional trunk exercises (d=3.56), and the smallest with students in the control group (d=0.29). In both experimental groups the difference between the mean in the initial and final state was statistically significant, while at students in the control group the aforementioned difference did not reach the level of statistical significance. Core stabilization exercises and traditional trunk exercises efficiently improve the muscular endurance of the trunk muscles. Trunk muscle strengthening is better recommended with core stabilization exercises, since they enable an efficient improvement of the muscular endurance without longterm detrimental effects on the spine

ROCK MASS DAMAGED ZONE CAUSED BY BLASTING DURING TUNNEL EXCAVATION

Izrada podzemnih rudničkih prostorija, tunela i odlagališta radioaktivnog otpada, podrazumijevaju primjenu jednakih odnosno sličnih tehnologija. Uslijed iskopa tunela miniranjem dolazi do određenog stupnja oštećenja stijenske mase oko konture presjeka iskopa. Oštećenja stijenske mase koja nastaju u neposrednoj okolini konture presjeka tunela izražene su proširenjem postojećih i stvaranjem novih pukotina, odnosno promjenom fizičko-mehaničkih svojstava stijenske mase. Prilikom izrade dubokih geoloških odlagališta radioaktivnog otpada zahtjevi po pitanju što manjeg oštećivanja stijene su jednaki ili veći u odnosu na tunele. Opisana istraživanja usmjerena su određivanju dubine zone oštećenja nastale miniranjem. Dubina zone oštećenja određivana je mjerenjem promjena fizičko-mehaničkih svojstava stijenske mase oko konture iskopa tunela. Istraživanjem su parametri bušenja i miniranja uspoređeni s dubinom i veličinom prostiranja oštećenja.Design of underground spaces, including tunnels, and repositories for radioactive waste include the application of the same or similar technologies. Tunnel excavation by blasting inevitably results in the damage in the rock mass around the excavation profile. The damage in the rock mass immediately next to the tunnel profile emerges as the expanding of the existing cracks and the appearance of new cracks, i.e. as the change of the physical and-mechanical properties of the rock mass. Concerning the design of deep geological repositories, requirements in terms of damaged rock are the same or more rigorous than for the design of tunnel. The aforementioned research is directed towards determining the depth of damage zone caused by blasting. The depth of the damage zone is determined by measuring the changes of physical and-mechanical properties of the rock mass around the tunnel excavation profile. By this research the drilling and blasting parameters were correlated with the depth and size of the damage zone

SSSL: Shoulder Surfing Safe Login

Classical PIN-entry methods are vulnerable to a broad class of observation attacks (shoulder surfing, key-logging). A number of alternative PIN-entry methods that are based on human cognitive skills have been proposed. These methods can be classified into two classes regarding information available to a passive adversary: (i) the adversary fully observes the entire input and output of a PIN-entry procedure, and (ii) the adversary can only partially observe the input and/or output. In this paper we propose a novel PIN-entry scheme- Shoulder Surfing Safe Login (SSSL). SSSL is a challenge response protocol that allows a user to login securely in the presence of the adversary who can observe (via key-loggers, cameras) user input. This is accomplished by restricting the access to SSSL challenge values. Compared to existing solutions, SSSL is both user-friendly (not mentally demanding) and cost efficient. Our usability study reveals that the average login time with SSSL is around 8 sec in a 5-digit PIN scenario. We also show the importance of considering side-channel timing attacks in the context of authentication schemes based on human cognitive skills

Chemical properties of topsoil in relation to lithology and geomorphology of high karst

Visokogorsko područje dinarskog krša obilježeno je raznolikošću reljefnih formi, koje su u kombinaciji s humidnom klimom i različitim odnosima dolomita i vapnenaca, posebice u pogledu brzine i načina trošenja, dodatni izvor varijabilnosti fiziografije tla. U Nacionalnom parku Risnjak dimenzijama se ističu dvije ponikve (Viljska ponikva - VIP i Velika ponikva - VP) gdje smo testirali hipotezu o postojanju značajnih razlika u fiziografiji površinskog dijela tla. Cilj je bio istražiti u kojoj se mjeri uzduž osojne i prisojne padine ponikve mijenjaju kemijske značajke površinskog dijela tla i očituje li se pri tomu i razlika između dviju ponikvi, s obzirom na postojanje razlike u njihovoj litološkoj građi i poziciji unutar gorskog masiva. Istraživanja su provedena tako da je u svakoj ponikvi postavljen transekt u pravcu ~sjever-jug preko dna ponikve, na komu je obavljeno uzorkovanje tla do dubine od 15 cm (ili do stijene, ako je tlo pliće). Pokazalo se da je u VIP izraženija diferencijacija prirode humusa u organičnom horizontu i da ona dobro korespondira s diferencijacijom vegetacije. U VP se fizička trošivost stijena (dolomitični supstrat) odražava na fiziografiji tla u obliku karbonatnosti i više pH-vrijednosti, koja u VIP raste od dna prema rubu ponikve, dok se u VP pH-vrijednost značajno ne mijenja uzduž padina. Na osojnoj ekspoziciji u VIP je udio organskog ugljika u tlu značajno veći (377 g kg–1) od udjela na prisojnoj ekspoziciji (97 g kg–1), pri čemu na osojnoj ekspoziciji udio organskog ugljika opada od dna prema rubu ponikve, a na prisojnoj ekspoziciji se očituje blagi rast. Za razliku od navedonoga, u VP udjel organskog ugljika ima obrnuti trend. Slične odnose i trendove pokazuje i udjel ukupnog dušika, osim pri dnu osojne padine u VIP, gdje je Ntot relativno nizak, a Corg relativno visok.Zaključno, fiziografija tla dubokih gorskih ponikvi krša pod snažnim je utjecajem prirode stijena u pogledu dolomitičnosti. Tlo povrh dolomita i dolomitičnih vapnenaca obilježeno je karbonatnošću. U ponikvama u masivima čvrstih vapnenaca može se očekivati na njihovim osojnim padinama karakteristične trendove pH-vrijednosti tla te udjela organskog ugljika i ukupnog dušika zbog vrlo izraženog hidrotermičkog, odnosno bioklimatskog trenda. Na prisojnim ekspozicijama takvih ponikvi analogni trendovi s karakterističnim gradijentima izostaju, što korespondira i s izostankom prepoznatljivog vegetacijskog slijeda.The high mountain area of ​​the Dinaric karst is characterized by a variety of relief forms, which in combination with humid climate and different relationships of dolomite and limestone, especially in terms of rate and nature of weathering, are an additional source of variability of soil physiography. In the Risnjak National Park, two sinkholes stand out in terms of dimensions (Viljska ponikva - VIP and Velika ponikva - VP), where we tested the hypothesis of the existence of significant differences in the physiography of the surface part of the soil. The aim was to investigate the extent to which the chemical characteristics of the surface part of the soil change along the shady and sunny slopes of the sinkhole and whether the difference between the two sinkholes is evident, given the difference in their lithological structure (VIP is sinkhole in limestone and VP is sinkhole in dolomitic limestones and calcite dolomites) and positions within the mountain massif. The research was carried out in such a way that in each sinkhole a transect was placed in the direction north-south over the bottom of the sinkhole, on which soil sampling was performed to a depth of 15 cm (or to the rock, if the soil is shallower). Sampling was performed on rows of profiles in 5 replicates, which were placed perpendicular to the transect with a height difference of 10 m (Fig. 1). In each sinkhole, 22 rows of profiles were set up, on which 110 soil samples were collected, and the pH value, carbonate content, organic carbon content and total nitrogen content were measured on them. The research showed that on the shady slope in VIP, in addition to vertical vegetation differentiation, there is also a differentiation of the nature of humus in the organic horizon (hemimor, modermor, sphagnomor). This differentiation is much less pronounced in the VP, and on the sunny slope in both sinkholes it is almost absent. In VP, the physical weathering of rocks (dolomitic substrate) is reflected in the physiography of the soil in the form of free carbonate and higher pH values ​​(Figs. 9 and 10). In VIP the pH rises from the bottom towards the edge of the sinkhole, both on the shady and sunny slope, while in VP the pH value does not change significantly, both along the shady and along the sunny slope. A recognizable factor in the spatial variability of carbonate content and pH value of this soil is phytopedoturbation in the form of tree felling and ejection of carbonate particles on the surface of the sinkhole slope, where they are exposed to gravitational and water erosion and further redistribution down the slope.At the shady slope in VIP, the share of organic carbon in the soil is significantly higher (377 g kg – 1) than the share at sunny slope (97 g kg – 1). At the shady slope the share of organic carbon decreases from the bottom to the edge of the sinkhole (Fig. 11), and a slight increase is evident on the sunny slope. In VP, the mean values ​​on the slopes and the trends of these shares on the slopes in relation to VIP have the opposite relationship (Fig. 12). Similar relatios and trends are shown by the share of total nitrogen (Fig. 13), except at the bottom of the shady slope in VIP. Here, the share of Ntot is relatively low, and the share of Corg is relatively high, so only in this part within both transects does C/N differ significantly from the remaining parts of the transects (Fig. 14).In conclusion, the soil physiography of deep karst sinkholes is strongly influenced by the nature of the rocks in terms of dolomiticity. The soil above the dolomite and dolomitic limestones is marked by carbonates. In deep sinkholes in solid limestone massifs, characteristic trends of soil pH and the content of organic carbon and total nitrogen can be expected on their shady slopes due to a very pronounced hydrothermal and bioclimatic trend. Analogous trends with characteristic gradients are absent on the sunny slopes of such sinkholes, which corresponds to the absence of a recognizable vegetation sequence

Laboratory germination testing of the sweet chestnut (Castanea sativa Mill.) according to ISTA rules

U radu su prikazani rezultati ispitivanja laboratorijske klijavosti i morfoloških značajki klijanaca europskoga pitomoga kestena (Castanea sativa Mill.). Uzorci za istraživanja sakupljeni su u submediteranskom području Hrvatske, a radni uzorak za ispitivanje klijavosti iznosio je 8×25 sjemenki. Sjeme je do ispitivanja klijavosti čuvano tri mjeseca u hladnjaku na temperaturi od 3 °C. Postotak laboratorijske klijavosti utvrđen je prema postotku pravilnih klijanaca koji su normalno proklijali nakon 27 dana ispitivanja. Ispitivanje je provedeno u laboratoriju prema uvjetima koje propisuje ISTA (International Seed Testing Association). Izrađen je katalog sa slikama i opisom nepravilnih klijanaca. Na osnovi definiranih kodova nepravilnih klijanaca moguće je preventivno djelovati kako bi se reducirale nepoželjne jedinke. Rezultati ovog istraživanja od velike su koristi za razumijevanje složenoga procesa klijanja sjemena, kako u laboratoriju, tako i šumskim rasadnicima.The paper presents the results of laboratory germination testing and morphological characteristics of sweet chestnut (Castanea sativa Mill.) seedlings. The research samples were collected in the sub-Mediterranean region of Croatia, and the working sample for germination testing was 8×25 seeds. Prior to germination testing, the seeds were stored in a refrigerator for three months at 3°C. The percentage of laboratory germination was established according to the percentage of regular seedlings which germinated normally after 27 days of testing. The testing was carried out in a laboratory under the conditions prescribed by ISTA (International Seed Testing Association). A digital photo camera was used to take photos of all abnormal seedlings, which were then catalogued with their pictures and descriptions. The results of this research are very useful for nursery practice and can be applied in producing plants from seeds, rootstocks for grafting, and further raising of seedlings to be grown in plantations

Ispitivanje laboratorijske klijavosti pitomoga kestena (Castanea sativa Mill.) u skladu s pravilima ISTA

U radu su prikazani rezultati ispitivanja laboratorijske klijavosti i morfoloških značajki klijanaca europskoga pitomoga kestena (Castanea sativa Mill.). Uzorci za istraživanja sakupljeni su u submediteranskom području Hrvatske, a radni uzorak za ispitivanje klijavosti iznosio je 8×25 sjemenki. Sjeme je do ispitivanja klijavosti čuvano tri mjeseca u hladnjaku na temperaturi od 3 °C. Postotak laboratorijske klijavosti utvrđen je prema postotku pravilnih klijanaca koji su normalno proklijali nakon 27 dana ispitivanja. Ispitivanje je provedeno u laboratoriju prema uvjetima koje propisuje ISTA (International Seed Testing Association). Izrađen je katalog sa slikama i opisom nepravilnih klijanaca. Na osnovi definiranih kodova nepravilnih klijanaca moguće je preventivno djelovati kako bi se reducirale nepoželjne jedinke. Rezultati ovog istraživanja od velike su koristi za razumijevanje složenoga procesa klijanja sjemena, kako u laboratoriju, tako i šumskim rasadnicima

Ispitivanje laboratorijske klijavosti pitomoga kestena (Castanea sativa Mill.) u skladu s pravilima ISTA

U radu su prikazani rezultati ispitivanja laboratorijske klijavosti i morfoloških značajki klijanaca europskoga pitomoga kestena (Castanea sativa Mill.). Uzorci za istraživanja sakupljeni su u submediteranskom području Hrvatske, a radni uzorak za ispitivanje klijavosti iznosio je 8×25 sjemenki. Sjeme je do ispitivanja klijavosti čuvano tri mjeseca u hladnjaku na temperaturi od 3 °C. Postotak laboratorijske klijavosti utvrđen je prema postotku pravilnih klijanaca koji su normalno proklijali nakon 27 dana ispitivanja. Ispitivanje je provedeno u laboratoriju prema uvjetima koje propisuje ISTA (International Seed Testing Association). Izrađen je katalog sa slikama i opisom nepravilnih klijanaca. Na osnovi definiranih kodova nepravilnih klijanaca moguće je preventivno djelovati kako bi se reducirale nepoželjne jedinke. Rezultati ovog istraživanja od velike su koristi za razumijevanje složenoga procesa klijanja sjemena, kako u laboratoriju, tako i šumskim rasadnicima