Primjena toplinskog spremnika za povećanje učinkovitosti i isplativosti pogona postrojenja u sklopu centraliziranih toplinskih sustava

Visokoučinkovita kogeneracija i centralizirani sustavi grijanja i hlađenja imaju velik potencijal za smanjenjem troškova primarne energije, koji je u zemljama EU u velikoj mjeri neiskorišten. Centralizirani toplinski sustavi imaju veliku važnost u planiranju i vođenju budućih energetskih sustava s obzirom da omogućavaju veću implementaciju obnovljivih izvora energije, veću fleksibilnost vođenja i potencijalno im smanjuju troškove. Primjena toplinskih spremnika može imati pozitivan utjecaj na centralizirani toplinski sustav povećavajući mu efikasnost rada proizvodnih jedinica, što često znači i smanjenje troškova. U kombinaciji s dizalicama topline toplinski spremnici imaju velik potencijal u integraciji obnovljivih izvora. Ovaj rad se bavi upravo implementacijom toplinskog spremnika i dizalice topline u centralizirani toplinski sustav. U sklopu rada izrađen je model za optimizaciju troškova rada, koji uključuje energetske tokove na izlazu iz analiziranih postrojenja, njihove učinkovitosti i rad toplinskog spremnika, na temelju kojeg je provedena analiza slučaja za grad Karlovac

Eksperimentalno određivanje hidrodinamičkih značajki osigurača protoka plina

Cilj ovoga rada je eksperimentalno određivanje hidrodinamičkih značajki osigurača protoka plina. Određivane su hidrodinamičke značajke osigurača protoka plina PL-GS 25 Z, tip C. Takvi osigurači imaju veliku primjenu u postojećoj niskotlačnoj gradskoj plinskoj mreži s ulaznim tlakom do bar i protokom do m3/h. Glavna namjena im je zaustavljanje protoka plina unutar niskotlačnog plinskog cjevovoda u slučaju vanjskih oštećenja ili bilo kakvih drugih pojava koje uzrokuju nagli pad tlaka iza samog osigurača. Ovakva izvedba osigurača u uporabi je već više od godina. Unatoč njihovoj dugogodišnjoj primjeni osigurači protoka plina dosad nisu u potpunosti teorijski analizirani, radi čega se pristupilo eksperimentalnom određivanju njihovih hidrodinamičkih značajki u okviru ovog rada. Rad je proveden kroz nekoliko segmenata: - Definiran je hidrodinamički model temeljen na pretpostavkama izotermičkog, nestlačivog i jednodimenzijskog strujanja zraka kroz ispitivani osigurač protoka plina. Dimenzijskom analizom utvrđena je međusobna ovisnost osnovnih bezdimenzijskih značajki. - Osigurač je nadograđen aluminijskim utorom koji na sebi ima navoj za regulaciju pomaka pomičnog dijela osigurača. Ovime se dobiva točno određena promjena površine kroz koju struji plin u ovisnosti o pomaku pomičnog dijela osigurača. - Osigurač je ugrađen u postojeću instalaciju za ispitivanje kućnih regulatora tlaka u Gradskoj plinari Zagreb namijenjenu ispitivanju raznih uređaja koji se uobičajeno koriste u niskotlačnoj plinskoj mreži. Provedene su manje modifikacije sustava s obzirom na brtvljenje postojeće instalacije. - Provedena su mjerenja tlaka, protoka i temperature fluida za zadano područje otvora pomičnog dijela osigurača, te za zadano područje ulaznih tlakova i protoka. Ispitivanja su provedena za pomake otvora pomičnog dijela od 0,2625 mm do 1,05 mm, vrijednosti ulaznog pretlaka od 20 mbar do 420 mbar i protoke u području od 0 m3/h do 25 m3/h. - Analiza rezultata mjerenja je provedena s obzirom na ovisnost koeficijenta lokalnog gubitka o Reynoldsovom broju za zadano područje otvora osigurača. Izvedeni su matematički izrazi koji kvantificiraju hidrodinamičke značajke osigurača protoka plina

Incidence of Age Related Macular Degeneration in Correlation with Age, Sex and Occupation

This study assesses the relation between age related macular degeneration (ARMD) and age, sex and occupation. It is designed as a retrospective study conducted on patients presenting to the Eye Polyclinic »Dr. L. Pavi~evi}«, Rijeka, Croatia, during the years 1995, 2000 and 2005. and included total of 6617 patients. The number of patients diagnosed with ARMD, their age and sex distribution, as well as the correlation between occupation type (indoor /outdoor) and the incidence of ARMD were analyzed. The results of our study show that the incidence of ARMD is slightly increased in female vs. male, strongly age related, as expected, and significantly increased in patients with outdoor type of occupation. Besides, an increasing trend of incidence is noted

RESOLVING DATABASE CONSTRAINT COLLISIONS USING IIS*CASE TOOL

Integrated Information Systems*Case (IIS*Case) R.6.21 is a CASE tool that we developed to support automated database (db) schema design, based on a methodology of gradual integration of independently designed subschemas into a database schema. It provides complete intelligent support for developing db schemas and enables designers to work together and cooperate reaching the most appropriate solutions. The process of independent design of subschemas may lead to collisions in expressing the real world constraints and business rules. IIS*Case uses specialized algorithms for checking the consistency of constraints embedded in the database schema and the subschemas. IIS*Case supports designers in reviewing and validating results obtained after each step of the design process. The paper outlines the process of resolving collisions. A case study based on an imaginary production system is used to illustrate the application of IIS*Case. Different outcomes and their consequences are presented

RESOLVING DATABASE CONSTRAINT COLLISIONS USING IIS*CASE TOOL

Integrated Information Systems*Case (IIS*Case) R.6.21 is a CASE tool that we developed to support automated database (db) schema design, based on a methodology of gradual integration of independently designed subschemas into a database schema. It provides complete intelligent support for developing db schemas and enables designers to work together and cooperate reaching the most appropriate solutions. The process of independent design of subschemas may lead to collisions in expressing the real world constraints and business rules. IIS*Case uses specialized algorithms for checking the consistency of constraints embedded in the database schema and the subschemas. IIS*Case supports designers in reviewing and validating results obtained after each step of the design process. The paper outlines the process of resolving collisions. A case study based on an imaginary production system is used to illustrate the application of IIS*Case. Different outcomes and their consequences are presented

CYFRA 21-1 in Non-Small Cell Lung Cancer – Standardisation and Application during Diagnosis

There is no ideal tumour marker at present. The clinical application of CYFRA 21-1 is possible once a thorough standardisation process is carried out. Standardisation is achieved by determining the reference range in asymptomatic population, benign and malignant lung diseases, and benign and malignant diseases of other organs. Furthermore, it depends on knowledge of research population characteristics, patient medical histories and individual diagnostic procedure results, the size of research target samples and the clinically defined control groups. The cut-off level of CYFRA 21-1 for non-small cell lung cancer (NSCLC) is 1.72 ng/mL in the Croatian population. It is based on the clinically applicable sensitivity of 78% and specificity of 95% in benign lung diseases. The cut-off value is verified by clinical findings. For clinicians the level of CYFRA 21-1 is an early sign of NSCLC in relation to all the benign lung diseases and all the benign diseases of other organs, of which it was confirmed that they can influence the above level, provided that NSCLC is verified using standard diagnostic methods. The level of CYFRA 21-1 is also influenced by the time of sampling in relation to other diagnostic invasive procedures. The marker is clinically applicable if clinical findings verify it; otherwise, it is useless. This research has involved 343 healthy persons, 474 patients with a benign disease and 4440 patients with a malignant disease, 2453 of whom suffer from NSCLC. The sensitivity of CYFRA 21-1 in NSCLC is 78%, in squamous cell lung cancer (SQC) 84.6%, in adenocarcinomas (AD) 74.3% and in large cell lung cancer (LCC) 75.3%. The level of CYFRA 21-1 differs significantly between healthy persons, benign and malignant diseases (p<10–3). There are differences between the three histological types of NSCLC (p<10–6) and according to T and N (p<10–3). The level of CYFRA 21-1 prompts clinicians to repeat the clinical procedure during diagnosis, and helps to detect the disease earlier and implement treatment in NSCLC. We have achieved high concordance between marker findings and clinical diagnostic

Changes in the anterior segment of the eye in workers employed in the manufacture of coke

Provedeno ispitivanje u odnosu na očne smetnje u radnika u proizvodnji koksa pokazalo je u visokom postotku promjene prednjeg segmenta oka. Registrirani simptomi hiperemije konjunktive, pingvekula, pigmentacije i konjunktivitisa najvjerojatnije su vezani za specifičan rad i izloženost ugljenoj prašini i neugodnim nadražljivcima. U radnika s manje od dvije godine ekspozicije nema promjena u sekreciji suza, u onih koji rade između 2 - 7 godina dominira hipersekrecija, a nakon duže izloženosti dolazi u većini izloženih radnika do hiposekrecije.An investigation carried out of eye disorders in workers employed in the manufacture of coke demonstrated a high percentage of changes in the anterior segment of the eye. Registered symptoms such as conjunctival hyperemia, pinguecula, pigmentation and conjuctivitis were most probably connected with specific work and exposure to coal dust and irritants. In workers exposed for less than two years there were no changes in lacrimal secretion. In those working for 2 - 7 years excessive hypersecretion dominated, and after a longer period of exposure the majority of workers had hyposecretion