24 research outputs found
Modeliranje i detekcija kvara u medicinskim elektrodama
In this paper we have studied the failures in medical electrodes such as electroencephalogram electrodes (EEG) being used for collecting brain signals. As those electrodes have to guarantee high level of reliability it is important to explore and predict the possible occurrence of failures in there structure. The electrode tip (needle) made of stainless steel is covered with thin oxide film acting as a dielectric and determing the total electrode resistance. In fact, studying the fluctuations of that resistance gives the insight into defects of the whole structure. The electrical properties of the oxide layer are characterized by charge hopping mechanism and the total resistance could be modeled by implementing random resistance network (RRN) methodology. The applied computational algorithm is based on Monte Carlo simulation procedure with direct and iteration methods. The obtained simulation results show non-gaussian Bramwell-Holdsworth-Pinton (BHP) distribution of the total resistance fluctuations, and they verified by the experiments.U ovom je radu razvijen model za simulaciju predviÄanja defekata u posebnim elektrodama koje se koriste pri mjerenju i prikupljanju signala mozga. KljuÄni dio elektrode je njen ÄeliÄni vrh prekriven tankim oksidnim slojem koji ujedno djeluje kao dielektrik. Upravo fluktuacije vrijednosti otpora dielektrika odnosno njihovo rasipanje od normalne do BHP raspodjele, koriÅ”tene su kao osnova predloženog modela. Pritom je primjenjena metodologija mreže nasumiÄnih otpora (RRN), algoritam temeljen na Monte-Carlo simulacijama kao i teorija usmjerene perkolacije. Definiran je i poseban parametar kao indeks intervala valjanosti za svaku elektrodu. Simulacije su potvrÄene mjerenjem u laboratorijskim uvjetima na komercijalnim EEG elektrodama
OdreÄivanje sklonosti toplim pukotinama aluminijskih legura metodom lijevanja prstena
Ovaj rad sastoji se od dva dijela: teorijskog i eksperimentalnog. U teorijskom dijelu detaljno je opisan proces skruÄivanja aluminija i njegovih legura te mehanizam nastanka toplih pukotina. Tople pukotine su Äesta i ozbiljna greÅ”ka u ljevarskim legurama te jedan od glavnih pokazatelja koji definiraju sposobnost lijevanja neke legure. Pukotine nastaju u zadnjoj fazi skruÄivanja u temperaturnim podruÄjima blizu solidusa, a nalaze se unutar ili na povrÅ”ini odljevka. \Na sklonost odreÄene legure prema nastanku toplih pukotina utjeÄu razni Äimbenici, meÄu kojima svakako valja izdvojiti kemijski sastav legure, veliÄinu zrna, temperaturu ulijevanja te brzinu ohlaÄivanja. U eksperimentalnom dijelu ovog rada provedeno je ispitivanje sklonosti Al-legura prema nastanku toplih pukotina metodom prstenova razliÄitih Å”irina R. Legure su lijevane u jednokratne pjeÅ”Äane kalupe. Kalupna mjeÅ”avina sastojala se od osnovnog materijala (kvracni pijesak), veziva (bentonit), vode i dodataka. Eksperimentalni dio rada proveden je na Fakultetu strojarstva i brodogradnje u Zagrebu, u Laboratoriju za ljevarstvo. Cilj ovog rada bio je ispitati legure AlSi12, AlSi9Mg i AlMg1. Ispitivanje je provedeno lijevanjem Äetiri prstena razliÄitih unutarnjih promjera za svaku leguru. Vanjski promjer je bio isti, a varirana je Å”irina prstena R, promjenom unutarnjeg radijusa. \Nakon lijevanja provedena je simulacija punjenja kalupa i skruÄivanja odljevka. Rezultati pokazuju da je legura AlMg1 vrlo sklona nastanku toplih pukotina i ne smije se lijevati u kalupe koji ne dopuÅ”taju slobodno stezanje legure prilikom skruÄivanja. Legure AlSi12 i AlSi9Mg nisu sklone nastanku toplih pukotina
Endobronchial ultrasound-guided transbronchial fine needle aspiration (EBUSTBNA): Solitary fibrous tumor of the mediastinum
A solitary fibrous tumor is a rare type of mesenchymal neoplasm with a described incidence of 1 new case in a million people a year. It is slowgrowing tumor that can arise almost anywhere in the body, usually with benign characteristics with little or no symptoms, until it grows big enough to cause symptoms of compression. In this case report we presented a patient with a rare case of a mediastinal solitary fibrous tumor
SPONTANI PNEUMOMEDIJASTINUM NAKON SPIROMETRIJE U BOLESNIKA DVA MJESECA NAKON PREBOLJENJA PNEUMONIJE COVID-19
We present a case report of a middle-aged man who developed spontaneous pneumomediastinum and pneumothorax after performing spirometry. The patient was evaluated in post-COVID-19 outpatient hospital 70 days after his initial hospitalization for severe COVID-19 pneumonia. After performing forced expiratory maneuver on spirometry, high-resolution computed tomography (HRCT) showed a small right-sided pneumothorax and pneumomediastinum along the bronchi, large blood vessels, and cardiac contour with āground-glassā opacifications in all lung lobes. The patient was cardiopulmonary compensated and conservative treatment was recommended. The long-term consequences of COVID-19 pneumonia are still not suffi ciently known. Spontaneous pneumomediastinum can very rarely occur as a complication during regular investigation of lung function caused by forced expiratory maneuver on spirometry. Due to lung parenchymal damage, pneumomediastinum with or without pneumothorax in post-COVID-19 patients occurring after spirometry can be expected as a rare but possible complication.Spontani pneumomedijastinum (SPM) je rijetka komplikacija pluÄnih bolesti. U ovom prikazu bolesnika opisan je bolesnik koji je 70 dana nakon hospitalizacije zbog teÅ”ke pneumonije COVID-19 nakon izvoÄenja spirometrije dobio spontani pneumomedijastinum i pneumotoraks. Na HRCT-u (CT toraksa visoke rezolucije) prsnog koÅ”a nakon spirometrije bio je vidljiv manji desnostrani pneumotoraks te pneumomedijastinum uz uzorak takozvanog \u27mlijeÄnog stakla\u27 u svim pluÄnim režnjevima. BuduÄi da je bolesnik bio kardiopulmonalno kompenziran, preporuÄen je konzervativni pristup i daljnje praÄenje. BuduÄi da su dugoroÄne posljedice pneumonije COVID-19 joÅ” uvijek nedovoljno poznate, uÄinci infekcije na respiracijski te druge organske sustave pratit Äe se u iduÄim godinama. SPM može nastati kao vrlo rijetka komplikacija redovnog ispitivanja pluÄne funkcije spirometrijom tijekom koje se provodi forsirani ekspirij. S obzirom na oÅ”teÄenje pluÄnog parenhima uzrokovano pneumonijom COVID-19, Pneumomedijastinum se može oÄekivati kao moguÄa, iako rijetka komplikacija nakon provoÄenja spirometrije u razdoblju bolesti \u27post-COVID-19\u27
Insulation Verification Using Low Voltage and High Current Sensitivity
The classic approach for determining insulating resistance by using commercial testers is not reliable for testing different types of insulation, especially for cables with one conductor and nanoelectronic oxide-based devices (nanotransistors). In this paper an alternative low-voltage method for measuring insulation resistance based on strongly increased current sensitivity is proposed. The proposed method of measuring insulation resistance at low voltages is realized by using a high sensitivity Keithley SMU 2612 unit. The verification of the proposed method is made by measuring insulation resistance of medical Corkscrew Electrode and gate oxide resistance for nano-scaled MOSFET. Finally, results of measuring insulation resistance obtained by commercial testers and proposed method in the verification process are compared
Guest Editorial: Smart Systems and Architectures
none5siÅ oliÄ, P. ; PerkoviÄ, T. ; MarasoviÄ, I. ; LĆ³pez-De-IpiƱa, D. ; Patrono, L.Å oliÄ, P.; PerkoviÄ, T.; MarasoviÄ, I.; LĆ³pez-De-IpiƱa, D.; Patrono, L
Web shop selling products of small farms
U ovom radu opisana je izrada funkcionalne mrežne aplikacije za prodaju proizvoda. Sastoji se od dvije baze podatka: jedna za registraciju korisnika i druga za prodaju proizvoda. Mrežna aplikacija omoguÄuje korisnicima pretraživanje veÄ predanih oglasa, odnosno proizvoda, predaju oglasa i naruÄivanje proizvoda. Aplikacija je izraÄena pomoÄu ASP.NET Web Formi, koje su takoÄer detaljno opisane u ovom radu. Posebno se opisuju znaÄajke i prednosti ASP.NET Web Formi i zbog Äega je upravo ta tehnologija koriÅ”tena za izradu mrežne aplikacije. Za spremanje podataka u bazu podataka koriÅ”tena je LINQ tehnologija, stoga je ukazano koje su prednosti i važnost te tehnologije u odnosu na SQL.This work describes the creation of a functional web application for product sales. It consists of two databases: one for user registration and another for sale of products. A network application allows users to search already submitted products, submitting and ordering products. The application was created using ASP.NET Web Forms, which is also described in detail in this work. Particularly describes the features and benefits of ASP.NET Web Forms, which is why this technology was used to create this web application. LINQ technology was used to store data in the database, so the advantages and importance of this technology were compared to SQL