Residual life estimation of cracked aircraft structural components

Predmet ovog istraživanja je usmeren na uspostavljanje proračunske procedure za analizu čvrstoće elemenata avionskih konstrukcija sa aspekta zamora i mehanike loma. Za tu svrhu ovde će biti uspostavljena proračunska procedura za procenu preostalog veka elemenata avionskih konstrukcija tipa dela oplate krila i uški pod dejstvom cikličnih opterećenja konstantne amplitude i spektra opterećenja. Poseban aspekt istraživanja se odnosi na primenu gustine energije deformacije (GED) za procenu preostalog veka elemenata konstrukcija sa inicijalnim oštećenjima tipa prskotina. Za određivanje analitičkih izraza za faktore intenziteta napona ovde su korišćeni specijalni singularni konačni elementi. Verifikacija proračunskih procedura za procene preostalog veka je podržana sa sa analitičkim i eksperimentalnim rezultatima uključivši i testove na zamor posebno sa aspekta eksperimentalnog određivanja malociklusnih zamornih karakteristika materijala.The subject of this investigation is focused on developing computation procedure for strength analysis of damaged aircraft structural components with respect to fatigue and fracture mechanics. For that purpose, here will be defined computation procedures for residual life estimation of aircraft structural components such as wing skin and attachment lugs under cyclic loads of constant amplitude and load spectrum. A special aspect of this investigation is based on using of the Strain Energy Density (SED) method in residual life estimation of structural elements with initial cracks. To determine analytic formulae for the stress intensity factors here singular finite elements are used. Verification of computation procedures for residual life estimations will be supported with corresponding experimental tests for determination of low cyclic fatigue properties of materials and corresponding parameters of fracture mechanics, including fatigue tests of representative aircraft structural elements

Determination of piroxicam in pharmaceutical based on an oscillating chemical reaction

A novel procedure for kinetic determination of piroxicam (PX) by the concentration perturbations of the Bray-Liebhafsky (BL) oscillatory chemical system was proposed. The response of the BL matrix in a stable non-equilibrium stationary state close to the bifurcation point, to the perturbation by different concentrations of PX, is followed by a Pt-electrode. Under the optimized reaction conditions, the linear relationship between maximal potential shift ΔEm, and PX concentration was obtained in the concentration range 6.8 × 10−5 mol L−1 − 1.7 × 10−3 mol L−1 with a detection limit of 3.5 × 10−5 mol L−1 . The method had a rather good sample throughput (ST) of 45 samples h−1 with the recovery RCV = 103.7 %. Applicatibility of the proposed method to the direct determination of PX in pharmaceutical formulation (injections) was demonstratedPhysical chemistry 2012 : 11th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 201

Schizotypy: Current concepts and future research implications

Shizotipija je konstrukt koji se koristi kako bi se opisala grupa osoba sa simptomima koji ne ispunjavaju kriterijume za postavljanje dijagnoze shizofrenije, ali imaju sličnosti sa ovim kompleksnim i heterogenim psihiajtrijskim oboljenjem. MKB-10 opisuje shizotipiju kao privremeno stanje (shizotipalni poremećaj), dok je DSM-5 opisuje kao trajniji poremećaj (shizotipalni poremećaj ličnosti). S obzirom da se shizotipija prostire kroz normalnu, supkliničku i kliničku populaciju, temeljno teorijsko razumevanje ovog koncepta može biti od pomoći prilikom razvijanja mera procene shizotipije. Do sada, najveći deo psihometrijske evaluacije shizotipije bazirao se na varijetetima individualnih razlika (poremećaja) ličnosti. Ovaj članak se fokusira na evoluciju termina shizotipije, na razumevanje ovog fenomena, mogućnosti psihometrijske procene u skladu sa trenutnim modelima ličnosti i na klinička razmatranja koja bi dovela do poboljšane detekcije i intervencije u ovoj oblasti.Schizotypy is a construct used to describe a group of persons with symptoms which do not fulfill criteria for schizophrenia, but have some similarities with this complex and heterogeneous psychiatric disorder. ICD-10 describes schizotypy as a state (schizotypal disorder), while DSM-5 labels it as a trait marker (schizotypal personality disorder). Considering how schizotypy encompasses through the normal, subclinical and clinical population, a thorough theoretical understanding of this concept could be helpful in developing measures of assessment. So far, most of the tools for psychometric evaluation of schizotypy have focused only on abnormal personality. The present article focuses on the evolution of the term schizotypy, its current understanding, the possibilities of psychometric assessment in relation to contemporary constructs of personality and on clinical considerations for improved detection and intervention in this field

Autohtoni sojevi roda Lactobacillus izolirani iz Istarskog sira kao potencijalne starter kulture

Istrian ewe’s milk cheese is an autochthonous product that is manufactured for generations on small family farms in the Croatian peninsula Istria. Traditional Istrian cheese is made from unpasteurized ewe’s milk, without the addition of starter cultures. Consequently, the specific flavour and texture of the Istrian cheese is owed to metabolic processes of indigenous microflora of which Lactobacillus species play pivotal role. Characterisation and selection of indigenous lactobacilli may result in the potential use of selected strains as starter, bioprotective or even probiotic cultures. This study focuses on potential use of Lactobacillus plantarum and Lactobacillus casei isolated from traditional Istrian cheese as starter cultures, by using methods that determine their proteolytic, lipolytic, antimicrobial and haemolytic potential, as well as their ability of acidification, autoaggregation and survival in simulated gastrointestinal conditions. Our results indicated that from 12 representative strains most revealed a low or moderate proteolytic activity as well as absence of lipolytic and haemolytic activities. From 12 strains, 5 of them showed a medium to strong acidification ability and lowered the pH of milk below 5.00 after 24 hours of incubation. Furthermore, almost all isolates exhibited antimicrobial activity against Serratia marcescens, and lowest number of isolates showed antimicrobial activity against Staphylococcus aureus and Listeria innocua. The studied Lactobacillus strains revealed high survival rate in a simulated oral cavity and duodenum conditions, while the survival ability in a simulated gastric conditions was much lower. Ability to aggregate was low for all tested strains, after 3 hours and after 5 hours of incubation.Tradicionalni Istarski sir proizvodi se od nepasteriziranog ovčjeg mlijeka, bez dodatka starter kultura. Prema tome, specifična aroma i tekstura Istarskog sira pripisuje se, uz ostale faktore, metaboličkim procesima autohtone mikroflore od kojih vrste roda Lactobacillus imaju ključnu ulogu. Karakterizacija i izbor autohtonih sojeva laktobacila može dovesti do potencijalnog korištenje odabranih sojeva kao starter, zaštitnih ili probiotičkih kultura. U ovom istraživanju željeli smo istražiti tehnološki i probiotički potencijal sojeva Lactobacillus plantarum i Lactobacillus casei izoliranih iz tradicionalnog Istarskog sira pomoću metoda koje određuju njihov proteolitički, kazeinolitički, lipolitički, antimikrobni i hemolitički potencijal, kao i njihovu sposobnost zakiseljavanja, autoagregacije i preživljavanja u simuliranim gastrointestinalnim uvjetima. Svih 12 reprezentativnih sojeva pokazuju nisku do umjerenu proteolitičku aktivnost te odsutnost lipolitičke i hemolitičke aktivnosti. Od 12 sojeva, 5 je pokazalo jaku sposobnost zakiseljavanja, spuštajući pH mlijeka ispod 5,00 nakon 24 sati inkubacije. Nadalje, gotovo svi izolati pokazuju antimikrobno djelovanje u odnosu na vrstu Serratia marcescens te slabo antimikrobno djelovanje u odnosu na Staphylococcus aureus i Listeria innocua. Istraživani sojevi pokazali su visoku prosječnu stopu preživljavanja u simuliranim uvjetima usne šupljine i dvanaesnika, dok je prosječna stopa preživljavanja u simuliranim želučanim uvjetima bila znatno niža. Nakon 5 sati inkubacije, autoagregacijska sposobnost svih istraživanih sojeva bila je niska

Pulse perturbation technique for determination of piroxicam in pharmaceuticals using an oscillatory reaction system

A simple and reliable novel kinetic method for the determination of piroxicam (PX) was proposed and validated. For quantitative determination of PX, the Bray-Liebhafsky (BL) oscillatory reaction was used in a stable non-equilibrium stationary state close to the bifurcation point. Under the optimized reaction conditions (T = 55.0A degrees C, [H2SO4](0) = 7.60x10(-2) mol L-1, [KIO3](0) = 5.90x10(-2) mol L-1, [H2O2](0) = 1.50x10(-1) mol L-1 and j (0) = 2.95x10(-2) min(-1)), the linear relationship between maximal potential shift Delta E (m) , and PX concentration was obtained in the concentration range 11.2-480.5 A mu g mL(-1) with a detection limit of 9.9 A mu g mL(-1). The method had a rather good sample throughput of 25 samples h(-1) with a precision RSD = 4.7% as well as recoveries RCV a parts per thousand currency sign 104.4%. Applicability of the proposed method to the direct determination of piroxicam in different pharmaceutical formulations (tablets, ampoules and gel) was demonstrated

Risk Behaviors for Getting HIV Infection among University Students in Serbia

The objective of this study was to determine risk-taking behaviors for getting HIV infection among university students in Serbia. The study is based on a cross-sectional survey. Five hundred forty four undergraduate, first year students from two Belgrade universities were selected through random sampling, to answer a self-administrated anonymous questionnaire. Data were collected from 252 students from the Faculties of Medical Sciences, University of Belgrade (FMS) and 292 students from the Faculties of Arts, University of Arts Belgrade (FA). The differences between two groups of students and between students with risk and non-risk behavior were assessed by the χ2 and t-test. Besides that, multivariate techniques such as factor analysis and multivariate logistic regression were used in statistical analysis. Smoking (Odds Radio – OR=5.05, 95% Confidence Interval – CI=3.10–8.24), studying FA, (OR=4.17, 95%CI=2.69–6.46), male sex (OR=3.85, 95% CI=2.38–6.25), committing offences (OR=1.51, 95%CI=1.09–2.08) and older age (OR=1.31, 95%CI=1.10–1.55) were the most significant factors connected with the risk-taking behaviors for HIV transmission among the students. In conclusion, HIV prevention efforts must be sustained and designed to reach young people and to prevent patterns of risky behaviors before they start

Ima li sindrom izgaranja nastavnika na poslu sezonski karakter?

The aim of this cross-sectional study was to compare occupational burnout in two groups of teachers from the district of Bijeljina (Bosnia and Herzegovina) measured with the Serbian version of the Maslach Burnout Inventory survey for workers in human services (MBI-HSS) at the beginning (group 1) and the end of the school year 2018/2019 (group 2) to see if there are seasonal differences. The questionnaire also included standard sociodemographic data and job description (primary and/or secondary school position, length of service, and overtime work). The prevalence of emotional exhaustion and depersonalisation was low in both groups. However, emotional exhaustion and depersonalisation scores significantly shifted to higher values between the beginning and the end of the school year. We also found a statistically significant association between emotional exhaustion and overtime and between depersonalisation and work in a secondary school (p<0.05). These findings invite further research of occupational burnout seasonality in schoolteachers, preferably by following up cohorts which would be controlled for sociodemographic and work-related variables.U ovom je presječnom istraživanju uspoređena prevalencija sindroma izgaranja na poslu u dvjema skupinama nastavnika na području Bijeljine u Bosni i Hercegovini te je procijenjen njegov sezonski karakter. Sindrom izgaranja na poslu mjeren je na početku (skupina I.) i na kraju školske 2018./2019. godine (skupina II.). Za potrebe ovoga istraživanje korištena je srpska inačica Maslachina upitnika izgaranja na poslu za stručnjake pomagačkih zanimanja (izv. Maslach Burnout Inventory Survey for Workers in Human Services, krat. MBI-HSS). Upitnik je uključivao i standardne sociodemografske podatke, kao i podatke o radnomu mjestu (rad u osnovnoj i/ili srednjoj školi, dužina radnog staža i prekovremeni rad). Prevalencija emocionalne iscrpljenosti i depersonalizacije bila je niska u objema skupinama ispitanika na početku mjerenja, ali se na kraju školske godine povećala. Utvrđena je statistički značajna razlika između emocionalne iscrpljenosti i prekovremenoga rada, kao i između depersonalizacije i rada u srednjim školama (p<0,05). Rezultati istraživanja upućuju na potrebu daljnjeg ispitivanja sezonskoga karaktera sindroma izgaranja na nastavničkom poslu, po mogućnosti kohortnim istraživanjem kojim bi se pratile sociodemografske i radne varijable ispitanika

Kinetics of the Bray-Liebhafsky oscillatory reaction perturbed by polymer supported cobalt catalyst

The Bray-Liebhafsky (BL) oscillatory reaction generated in the batch reactor at 62- 68 oC was perturbed by cobalt(II)-nitrate, supported on the macroreticular copolymer of poly-4-vinylpyridine with divinylbenzene (Co-PVPDVB). The kinetic data was analyzed of the complex pathways of the hydrogen peroxide decomposition in the examined BL reaction. The obtained results confirm that the kinetics of the BL reaction in the presence Co-PVPDVB comes partially from the Co-catalyst and partially from the macroreticular copolymer support.Oscilatorna reakcija Bray-Liebhafsky (BL) realizovana u zatvorenom reaktoru na temperaturi 62-68 oC je perturbovana sa kobalt(II)nitratom ugrađenim na makroretikularnom kopolimeru poli-4-vinilpiridina sa divinilbenzenom (Co- PVPDVB). Analizirani su kinetički podaci kompleksnih reakcionih puteva razlaganja vodonikperoksida u ispitivanoj BL reakciji. Dobijeni rezultati potvrđuju da je u prisustvu Co-PVPDVB kinetika BL reakcije delimično određena Co-katalizatorom, a delimično makromolekularnim kopolimernim nosačem katalizatora

Las bacterias del ácido láctico en la producción de los chorizos crudo-fermentados tradicionales

Spontano fermentirane trajne kobasice, koje se proizvode u domaćoj radinosti, prepoznati su i cijenjeni tradicionalni proizvodi. Odlikuju se specifičnim senzornim karakteristikama i izvor su vrijednih hranjivih sastojaka. Međutim, različit izbor sirovine i dodataka te varijabilni uvjeti proizvodnje dovode do neujednačene mikrobiološke i senzorne kvalitete tradicionalnih kobasica. Ključnu ulogu u osiguravanju zdravstvene ispravnosti takvih proizvoda imaju prirodno prisutne, autohtone populacije bakterija mliječne kiseline (BMK). Selektirane i aplicirane kao starter kulture autohtone populacije BMK mogle bi smanjiti rizike uzorkovane mikrobiološkom kontaminacijom za vrijeme klanja, odnosno lova i tijekom prerade mesa te povoljno utjecati na organoleptičke karakteristike krajnjeg proizvoda. Stoga je cilj ovog rada pokazati specifičnosti bakterija mliječne kiseline i mogućnosti njihove aplikacije u fermentaciji tradicionalnih suhih kobasica proizvedenih od mesa domaćih ili divljih životinja.Spontaneously fermented dry sausages that are produced locally are considered to be recognized and appreciated traditional products. They are characterized by specific sensory properties and represent a source of valuable nutrients. However, a multiple choice of raw materials and additives, as well as varying production conditions affect variable microbiological and sensory quality of traditional sausages. The inherently present, indigenous population of lactic acid bacteria (LAB) plays a key role in ensuring the health and safety of such products. Indigenous populations of LAB that are selected and applied as starter cultures could not only reduce risks caused by microbial contamination during slaughtering or hunting and during the processing of meat, but could also favourably affect the organoleptic properties of the end product. The aim of this paper was therefore to demonstrate the specificity of lactic acid bacteria and the possibility of their application in the fermentation of traditional dry sausages that are produced from the meat of domestic or wild animals.Hausgemachte spontan fermentierte Dauerwürste aus Wildeisch sind ein anerkanntes und geschätztes Traditionsprodukt, das sich durch besondere sensorische Eigenschaften auszeichnet und eine Quelle von hochwertigen Nährstoen darstellt. Die Wahl von unterschiedlichen Rohstoen und Zusätzen sowie die veränderlichen Produktionsbedingungen führen zu einer unausgewogenen mikrobiologischen und sensorischen Qualität solcher Würste. Eine ausschlaggebende Rolle bei der Sicherstellung der gesundheitlichen Unbedenklichkeit solcher Produkte haben die von Natur aus anwesenden, autochthonen Populationen der Milchsäurebakterien. Als Starterkulturen selektiert und appliziert, könnten die Populationen der Milchsäurebakterien die durch die mikrobiologische Kontaminierung während der Jagd und/oder während der Fleischverarbeitung verursachten Risiken reduzieren und sich günstig auf die organoleptischen Eigenschaften des Endprodukts auswirken. Das Ziel dieser Arbeit ist es daher, die Besonderheiten der Milchsäurebakterien und die Möglichkeiten ihrer Anwendung in der Fermentierung von Wildwurst aufzuzeigen.Le salsicce di selvaggina a lunga conservazione, fermentate spontaneamente e prodotte artigianalmente, sono un prodotto noto e apprezzato. Esse hanno speciche caratteristiche sensoriali e sono fonte d’ingredienti altamente nutrienti. Tuttavia, una di!erente scelta delle materie prime e degli additivi e la variabilità delle condizioni di produzione rendono la qualità microbiologica e sensoriale di queste salsicce non uniforme. La popolazione autoctona di batteri lattici (BL), naturalmente presente, svolge un ruolo chiave nel garantire l’idoneità sanitaria di simili prodotti. Selezionati e applicati come cultura starter della popolazione autoctona di BL, potrebbero ridurre i rischi causati dalla contaminazione microbiologica durante la caccia e/o durante la lavorazione delle carni e incidere positivamente sulle caratteristiche organolettiche del prodotto nale. L’obiettivo di questo lavoro, quindi, consiste nel mostrare la specicità dei batteri lattici e la possibilità della loro applicazione nella fermentazione delle salsicce di selvaggina.Los chorizos crudo-fermentados de la carne de caza fermentados espontáneamente y hechos en casa son productos tradicionales reco- nocidos y valiosos. Son caracterizados por sus propiedades sensoriales especícas y son la fuente de los ingredientes altamente nutritivos. No obstante, tanto la selección diferente de la materia cruda y de los aditivos como las condiciones variables llevan a las calidades microbiológicas y sensoriales desniveladas de estos tipos de chorizos. Las bacterias del ácido láctico (BAL) autóctonas, que están presentes de forma natural, tienen el papel clave en la provisión de la seguridad sanitaria de este tipo de productos. Seleccionadas y aplicadas como cultivos iniciadores de la populación autóctona, las BAL podrían disminuir el riesgo causado por la contaminación microbiológica durante la caza y/o durante el procesamiento de la carne y de esta manera inuir positivamente sobre las propiedades organolépticas del producto nal. Por lo tanto el n de este trabajo fue mostras las especidades de las bacterias del ácido láctico y las posibilidades de su aplicación durante la fermentación de los chorizos de carne de caza

Risks for First Nonfatal Myocardial Infarction in Belgrade

The aim of this study was to investigate which one among possible risk factors are independently related to first nonfatal myocardial infarction (MI) in Belgrade population. Case-control study was conducted in Belgrade during the period 2005–2006. Case group comprised 100 subjects 35–80 years old who were hospitalized because of first nonfatal MI at the coronary care unit in Urgent Center, Belgrade. Control group consisted of 100 persons chosen among patients treated during the same period at the Institute of Rheumatology, Institute for Gastroenterology, and Clinic for Orthopedics, Belgrade, Serbia. Cases and controls were individually matched by sex, age (±2 years) and place of residence (urban/ rural communities of Belgrade). According to the multivariate analysis risk factors for MI occurrence were »good« socioeconomic conditions (OR=2.76), total alcohol consumption (OR=2.62) and consumption of brandy (OR=6.73), stressful life events taken together (OR=3.13) and stress because of close relative Ns death (OR=3.35), great financial problems (OR=31.64) and small financial problems (OR=8.47), hypertension (OR=2.39), MI among all relatives (OR=3.66), MI in father (OR=6.24), and low level of high density lipoprotein cholesterol (OR=152.41). Amateur sport activity in the past was negatively associated with MI development. The results obtained are mainly in accordance with other studies results and can be of help in development of strategy for coronary heart disease prevention in Serbia