UTJECAJ PETROGRAFSKIH OBILJEŽJA SILIKATNIH STIJENA NA KVALITETU AGREGATA

The mechanical properties of chrushed rock aggregates are greatly influenced by the petrographic characteristics of parent rock. The main objective of this study was to determine the relation between the petrographic characteristics of some volcanic and subvolcanic (silicate) rocks from Croatia, and the chrushing resistance of aggregates produced by their comminution. The aggregate resistance to chrusing was tested by means of the Los Angeles abrasion test. During this testing, an aggregate is subjected to dynamic load by impact and abrasion. The petrographic characteristics were examined with the petrographic and scanning electron microscope and by X-ray powder diffraction with CuKa (1,54 A) radiation. In order to obtain the most correct evaluation of aggregates chrushing resistance, four different values had been used - the recrushing index (Ir), the reduction ratio (RR), the Los Angeles abrasion value (LA) and the Los Angeles abrasion value residue (LAr). On the basis of the obtained results, the following petrographic factors have been revealed as the most important ones for rock aggregates resistance to crushing: a - the size of crystals, b - the form, arrangement and dimensions ratio of crystals, and, especially c - the presence of microfractures in parent rock.Petrografska obilježja ishodišne stijene bitno utječu na mehanička svojstva drobljenih kamenih agregata. Glavni cilj ovog rada bio je utvrditi odnose između petrografskih obilježja nekih vulkanskih i subvulkanskih (silikatnih) stijena i otpornosti prema drobljenju agregata dobivenih njihovih usitnjavanjem. Otpornost prema drobljenju ispitivana je metodom "Los Angeles". Tijekom ispitivanja agregat je izložen dinamičkim opterećenjima na udar i habanje. Mineralni sastav i druga petrografska obilježja određeni su petrografskim i elektronskim mikroskopom, te metodom rendgenske difrakcije na prahu vertikalnim rendgenskim goniometrom s CuKu (1,54 A) zračenjem. Kako bi se što točnije ocijenila otpornost prema drobljenju ispitivanih agregata korištena su četiri različita pokazatelja: koeficijent Los Angeles (LA), koeficijent Los Angeles ostatka (LAr), indeks pregranulacije (Ir) i stupanj usitnjavanja (PR). Na temelju dobivenih rezultata kao najvažnija petrografska obilježja kamenih agregata u pogledu otpornosti prema drobljenju izdvojeni su: a- veličina kristala; b- oblik, prostorni raspored i međusobni odnos veličine kristala; i, posebice c - prisustvo mikropukotina u ishodišnoj stijeni

Testing rock mass deformability with large flat jacks

U Iranu su na više mjesta obavljena velika ispitivanja deformabilnosti stijenske mase in situ za potrebe temeljenja nekoliko građevina. U radu su prikazani rezultati i način izvođenja pokusa velikim tlačnim jastucima i dan je kritički osvrt na metode interpretacije rezultata mjerenja. Opisana je potreba injektiranja kontakta jastuka i stijenske mase. Uspostavljen je odnos izmjerenih deformacijskih modula i modula određenih empirijskim postupcima za vapnenačku stijensku masu.Large scale rock-mass deformability testing was conducted in situ on several locations in Iran in order to define foundation possibilities for several structures. Test results and methods, involving the use of large flat jacks, are presented, and a critical overview on the interpretation of measurement results is given. The need to grout contact zones between the flat jack and the rock mass is explained. The relationship between the measured moduli of deformation, and the moduli determined by empirical limestone testing procedures, is defined

Endocrinological outcomes of pure endoscopic transsphenoidal surgery: a Croatian Referral Pituitary Center experience

AIM: To analyze early remission, complications, and pituitary function recovery after pure endoscopic endonasal transsphenoidal surgery (PEETS), a novel method in pituitary adenoma treatment. ----- METHODS: Testing of all basal hormone values and magnetic resonance imaging (MRI) were performed preoperatively and postoperatively (postoperative MRI only in nonfunctioning adenomas) in 117 consecutive patients who underwent PEETS in the period between 2007 and 2010. The series consisted of 21 somatotroph adenomas, 61 prolactinomas, and 4 corticotroph and 31 nonfunctioning adenomas. Sixty-three were macroadenomas and 54 were microadenomas. Remission was defined as hormonal excess normalization on the seventh postoperative day in functioning adenomas and as normal MRI findings approximately four months postoperatively in nonfunctioning adenomas. The presence of hypogonadism, growth hormone deficiency, and hypothyroidism was assessed on the seventh postoperative day. Hypocortisolism was assessed through necessity for replacement therapy within 18 months postoperatively. ----- RESULTS: Remission was achieved in 84% of patients: in 100% of microadenoma and 70% of macroadenoma patients (P<0.001, odds ratio [OR], 28.16, 95% confidence interval [CI], 1.61-491.36), respectively. Endocrinological complications occurred in 17.1% of patients: in 9% of microadenoma and 24% of macroadenoma patients (P=0.049, OR, 3.06; 95% CI, 1.03-9.08). Duration of empirical hydrocortisone replacement therapy was significantly shorter in microadenoma patients (P<0.001). Thirty-five percent of preoperatively present hormonal deficiencies improved after the surgery. Between tumor types there were no significant differences in remission, complications, and normal pituitary function recovery. ----- CONCLUSION: Patients with microadenomas had higher remission and lower complication rates following PEETS, emphasizing the necessity for early detection and treatment of pituitary adenomas. PEETS is a discussion-worthy method for microprolactinoma treatment

ODREĐIVANJE OTPONOSTI KAMENIH AGREGATA NA PREGRANULACIJU

The stone aggregates of dolomite, andesitic and spililized diabase were tested to estimate their response to abrasive-impact strain. Standardized and non-standardized estimation of recrushing action were utilized in the experiment. The focus of the study was to improve the estimation of resistance to the recrushing process. The assumption that there is a relationship between the degree of recrushing of the stone aggregates and the grain surface before recrushing was confirmed The investigation was performed by the use of the standardised method according to the HRN Standard (Los Angeles). For the complete evaluation of the aggregate several other methods in accordance to HRN were also applied. The values obtained are found to be the result of several factor which include structural, textural and mineral properties, as well as genesis, tectonics (postgenetic strain producing the micro-cleavage and cataclasis) and recrystallization. The influence of the size, shape together with the interrelationship of crystals and micro-blocks on the physical and mechanical properties were determined by electronic microscopy.Kameni agregati dolomita, andezita i spilitiziranog dijabaza podvrgnuti su ispitivanju na udarno huhajuća opterećenja. Korištene su normirane i nenormirane metode ocjene pregranulacijc. Posebna pažnja posvećena je poboljšanju ocjene otpornosti prema pregranulaciji. Potvrđene su pretpostavke da postoji ovisnost stupnja pregranulacije kamenih agregata o površini zrna agregata prije predrobljvanja. Ispitivanje je obavljeno normiranom metodom prema normativu HRN (LosAngeles). Za potpunu ocjenu agregata korištene su i druge metode ispitivanja prema HRN-u. Utvrđeno je da su dobivene vrijednosti posljedica strukturno-teksturnih i mineralnih značajki, geneze, tektonike (postgenetskih naprezanja koja uzrokuju mikroraspucanost i kataklaziranje) i rekristalizacije. Elektronskim je mikroskopom utvrđen utjecaj veličine, oblika i međusobne povezanosti kristala i mikroblokova na fizička i mehanička svojstva

Analysis of hydraulic properties of unsaturated expansive soil

Polazi se od toga da je za kvantitativni opis ponašanja ekspanzivnog tla nužno odrediti njegove hidrauličke značajke: krivulje retencije vode i promjene volumena te funkciju hidrauličke provodljivosti. Opisani su eksperimentalni i analitički postupci kojima su te karakteristike istraživanog tla procijenjene. Inicijalno zasićeni uzorci ekspanzivnog tla podvrgnuti su sušenju. Pokusi sušenja uspješno su simulirani numeričkim modelom ne temelju procijenjenih značajki materijala.The paper starts with assertion that, in order to make a quantitative description of expansive soil behaviour, it is indispensable to determine its hydraulic properties: water retention curves and changes in volume, and the hydraulic conductivity function. Experimental and analytic procedures that were used to determine these properties of the studied soil are described. Initially saturated specimens of expansive soil were subjected to drying. The drying tests were successfully simulated via numerical model, based on the estimated properties of material

Engineering rock mechanics, testing, dilatometer, rock mass, deformability, dilatometer model

Prikazana su iskustva u primjeni različitih tipova dilatometara pri ispitivanju stijena. Uz teorijske osnove daju se i preporuke za upotrebu odgovarajućeg tipa dilatometra ovisno o deformabilnosti stijenske mase. Ističe se važnost interpretacije izmjerenih veličina i pravilne primjene rezultata. Ocjenjuju se rezultati mjerenja različitim tipovima dilatometara na više lokacija. Uspostavljena je korelacija dilatometarskog modula i modula iz velikih in situ ispitivanja vapnenca.Experience gained in the use of various dilatometer types in rock testing is presented. In addition to theoretical background information, the authors present recommendations for the use of individual dilatometer types depending on rock mass deformability. The significance of interpretation of measurement results and proper use of resulting information is emphasized. Measurement results obtained by different dilatometer types on a number of locations are analyzed. The correlation between the dilatometer module and the modules originating from big in situ limestone tests is established

Ishemijska apopleksija hipofize, hipopituitarizam i dijabetes insipidus: trijada specifična za nekrotizirajući hipofizitis

A rare case of necrotizing hypophysitis (NH) in a 52-year-old man presenting with pituitary apoplexy and sterile meningitis is described. This case indicates that the diagnosis of NH could be made without biopsy, based on concomitant presence of diabetes insipidus, hypopituitarism and radiologic features of ischemic pituitary apoplexy. Conservative management of pituitary apoplexy should be advised in NH. Additionally, this is the first report of a case of sterile meningitis caused by ischemic pituitary apoplexy.Autori prikazuju rijedak slučaj nekrotizirajućeg hipofizitisa u 52-godišnjeg muškarca koji se inicijalno prezentirao apopleksijom hipofize i sterilnim meningitisom. Ovaj slučaj ukazuje na mogućnost da je dijagnozu nekrotizirajućeg hipofizitisa moguće postaviti i bez biopsije ako postoji patognomonična trijada ovoga sindroma: dijabetes insipidus, hipopituitarizam i radiološki znakovi ishemijske apopleksije hipofize. Dodatno, ovo je prvi opisani slučaj sterilnog meningitisa uzrokovanog ishemijskom apopleksijom hipofize

Validation of diabetes knowledge questionnaire in Croatian with assessment of diabetes knowledge and quality of life in patients with type 2 diabetes mellitus

Background. Diabetes mellitus (DM) is one of the biggest challenges in global healthcare and society in general. Assessment of the patient’s level of knowledge regarding diabetes is an important step in adapting group education programs to achieve better treatment outcomes. The aim of this study was to validate Diabetes Knowledge Questionnaire (DKQ) in Croatian language, to evaluate knowledge about diabetes and examine the relationship between knowledge and quality of life among type 2 DM patient’s in Croatia.Methods. The study was conducted as a cross-sectional study on 500 subjects. Validation of DKQ questionnaire in Croatian language was done using forward-backward method and internal consistency was examined using Cronbach’s Alpha. Quality of life was assessed using WHOQOL-BREF Questionnaire.Results. Good reliability and internal consistency of DKQ was confirmed (a = 0,740). Overall knowledge about diabetes was satisfactory (average DKQ score was 12,13). Longer duration of disease and previous education about diabetes were observed as predictive factors of better knowledge. No association was found between diabetes knowledge and quality of life.Conclusions. Our study confirms that DKQ is a good tool for assessing diabetes knowledge in Croatian language. Patients with DM demonstrated good diabetes knowledge but education in areas of self-care and nutrition needs to be improved which may increase quality of life