BERGSTRÖM-BOYCE VS. HYPERELASTIC RUBBER MODELS IN STRUCTURAL ANALYSIS OF TIRES

New viscoelastic/viscoplastic material models, such as Bergström-Boyce (BB) model, are known to bring advantages in finite element analysis (FEA) of rubber-based components. To test if the same is true in FEA of tires, a study was performed in which the hyperelastic Yeoh model, BB and dynamic Bergström-Boyce (DBB) models were used to characterize the tread of an existing 205/65 R16 tire. Curve fitting results for all material models as well as the results of the footprint and steady state rolling tire analyses are presented in the paper. There are notable differences between the obtained results at higher strain rates, when viscoelastic material behavior is dominant

DETECTION AND HANDLING EXCEPTIONS IN BUSINESS PROCESS MANAGEMENT SYSTEMS USING ACTIVE SEMANTIC MODEL

Although business process management systems (BPM) have been used over the years, their performance in unpredicted situations has not been adequately solved. In these cases, it is common to request user assistance or invoke predefined procedures. In this paper, we propose using the Active Semantic Model (ASM) to detect and handle exceptions. This is a specifically developed semantic network model for modeling of semantic features of the business processes. ASM is capable of classifying new situations based on their similarities with existing ones. Within BPM systems this is then used to classify new situations as exceptions and to handle the exceptions by changing the process based on ASM’s previous experience. This enables automatic detection and handling of exceptions which significantly improves the performance of bpm systems

USER DEFINED GEOMETRIC FEATURE FOR THE CREATION OF THE FEMORAL NECK ENVELOPING SURFACE

There is a growing demand for application of personalized bone implants (endoprostheses or macro-scaffolds, and fixators) which conform the anatomy of patient. Hence the need for a CAD procedure that enables fast and sufficiently accurate digital reconstruction of the traumatized bone geometry. Research presented in this paper addresses digital reconstruction of the femoral neck fracture. The results point out that User-Defined (geometric) Feature (UDF) concept is the most convenient to use in digital reconstruction of numerous variants of the same topology, such as in this kind of bone region. UDF, named FemoNeck, is developed to demonstrate capability of the chosen concept. Its geometry, controlled by a dozen of parameters, can be easily shaped according to anatomy of femoral neck region of the specific patient. That kind of CAD procedure should use minimally required set of geometric (anatomical) parameters, which can be easily captured from X-ray or Computed Tomography (CT) images. For the statistical analysis of geometry and UDF development we used CT scans of proximal femur of 24 Caucasian female and male adults. The validation of the proposed method was done by applying it for remodeling four femoral necks of four different proximal femurs and by comparing the geometrical congruency between the raw polygonal models gained directly from CT scan and reconstructed models

REVIEW OF BONE SCAFFOLD DESIGN CONCEPTS AND DESIGN METHODS

The paper brings out a review of existing, state-of-the-art approaches to designing the geometry of the scaffolds that are used for tissue engineering with a special emphasis on the macro scaffolds aimed for bone tissue recovery. Similar concepts of different authors are organized into groups. The focus of the paper is on determining the existing concepts as well as their advantages and disadvantages. Besides the review of scaffolds' geometry solutions, the analysis of the existing designs points to some serious misconceptions regarding the scaffold role within the (bone) tissue recovery. In the last section of the paper, the main requirements regarding geometry, that is, architecture and corresponding mechanical properties and permeability are reconsidered

Application of the AHP Method for Comparative Analysis of Software Systems in Traffic from the Aspect of Traffic Safety

It is generally known that traffic safety is influenced by humans, vehicles, and roads. Nowadays, when new technologies have taken over a large part of the traffic industry, the selection of relevant software, whose competition is great, presents a big problem for the decision-maker. Intelligent systems, such as Motion, SCOOT, and SCATS, are used for the implementation of a control strategy in order to manage signals on the traffic network, with the goal of increasing efficiency and traffic safety. These systems operate on the demand-responsive principle and have logic for traffic optimization which represents their main difference along with the optimization subject and method of the system functioning. The research included consideration of mentioned differences, software, and hardware architecture that have a significant impact on the system’s functionality since the detector’s locations themselves depend on the optimization subject. The implementation benefits are considered through the existing world’s projects. Based on the obtained data, the criteria used for the comparative analysis of these three systems were defined, from the aspect of traffic safety

Research on infrared emission spectra of pulverized coal ash deposits

U ovom radu se opisuje istraživanje spektralnih i totalnih emisivnosti toplotnog zračenja naslaga pepela ugljenog praha u ložištima termoelektrana. Spektri normalne emisivnosti u intervalu talasne dužine 2.5-25 μm, te totalna normalna emisivnost, su izmereni na dva uzorka sprašenog pepela u sloju debljine reda veličine mm, na 560→1460→560 K u toku zagrevanja i - hlađenja. Spektralna emisivnost raste sa porastom temperature kao i talasne dužine zračenja pepela. Sprašeni pepeo se sinteruje i topi na temperaturi nad 1200K. Emisivnost sinterovanog pepela je veća od emisivnosti nesinterovanog praha. Autori predlažu, navodeći jedan konkretan primer, korelisanje eksperimentalno dobijenih spektralnih emisivnosti naslaga pepela, kontinualnim krivama čije formule definišu zavisnosti emisivnosti od talasne dužine i temperature t.j. ε = ε (λ,T). Može se očekivati da će korišćenje predložene formule, uz vrednosti parametara određene pomoću predloženog postupka, u velikoj meri pojednostaviti praktičnu primenu eksperimentalno određenih emisivnosti u okviru toplotnog proračuna postojećih kao i novih ložišta parnih kotlova na ugljeni prah.This paper deals with thermal radiation properties of ash deposits on a pulverized coal boiler of an electric power plant. Normal emittance spectra in the 2.5-25 μm interval, and total normal emittance, were measured on 2 kinds of ash layers of a mm magnitude order thickness, at 560→1460→560 K in heating and cooling. The emittance increases with ash radiation wavelength and temperature. Ash powder is sintered and fused above 1200 K. The emittance of the sintered layer is above that of the unsintered layer. The authors propose, and explain by example, correlating the experimentally obtained emittance spectra of ash deposits with a continuous curve, the formula of which defines the dependence of the emittance on wavelength and temperature, i.e. ε = ε (λ,T). Use of this formula, with parameter values determined by the proposed methodology, may greatly simplify the practical application of the experimentally determined emittances in the thermal design of existing and new steam boiler furnaces

Colorectal anastomosis dehiscence following radical surgical operation for rectal carcinoma

Background/Aim. Colorectal cancer (CRC) is one of the biggest health problems of modern humanity, especially in highly developed countries. In Serbia about 3,200 patients suffer from CRC, out of whom about 1,100 patients suffer from rectal cancer (RC), while about 2,100 patients suffer from other colon segments cancer. The aim of the study was to show the incidence genesis of one of the possible early postoperative complications regarding dehiscence of the colorectal anastomosis (CRA) with a group of patients suffering from RC and operated by using sphincter-saving procedures, in the period from 1993 to 2007, and then to compare the incidence genesis of these complications with those in the published series of the reporting colorectal institutions. Methods. The research included 242 patients radically operated on for RC in a 15-year period using some of sphincter-saving procedures following by a careful analysis of the symptoms of subclinical dehyscencias not solved with the reintervention as well as of the clinically evidented dehyscencias mostly solved by reoperation. Results. With 22 (9.1%) patients in the first 10 postoperative days there were early postoperative symptoms of CRA dehiscence. In 6 (2.47%) of the patients there were subclinical signs of raised body temperature, less quantity of feces content, and after the conservative treatment they ended in spontaneous process of rehabilitation. In 16 (6.61%) patients there was clinically evidented anastomosis dehiscence followed by abundant drainage of feces content, signs of local peritonitis, pelvic sepsis, so we had to undertake surgical intervention. Conclusion. Comparing the results of a few tenths of published studies with our results we proved that performing and operative technique of colorectal anastomosis in the patients suffered and radically surgically treated for RC, is quite adequate with the operative technique in reporting world institutions that are engaged in surgical treatment of RC

Usporedba odziva modela pneumatika s detaljnim gaznim slojem i pojednostavljenog modela za analizu kotrljanja pneumatika u stacionarnom stanju

This paper deals with the level of detail that is necessary for representation of tread pattern in finite element tire models. Different methods for creation of tire tread mesh are systematized by two different criteria: the most common approaches and the finite element analysis type. Some of the representative approaches found in literature are given in more detail and their advantages and disadvantages discussed. An example from author’s experience, which describes the creation of finite element tire model with detailed tread for steady-state rolling analysis, is presented. The paper also brings a head-to-head comparison of the response of simplified and detailed tread tire models, subjected to a range of finite element analyses, from footprint analysis at static loading conditions to steady-state rolling cornering analysis.Ovaj rad se bavi razinom detalja koja je potrebna za prikaz šare gaznoga sloja u modela pneumatika namjenjenih analizi primjenom metode konačnih elemenata. Različite metode za izradu mreže konačnih elemenata su sistematizirane po dva različita kriterija: najčešćih pristupa i tipa analize primjenom metode konačnih elemenata. Neki od tipičnih pristupa koji se mogu naći u literaturi opisani su u više detalja i navedene su njihove prednosti i nedostaci. U članku je dat primjer iz iskustva autora, koji opisuje stvaranje modela pneumatika s detaljnim gaznim slojem za analizu kotrljanja u stacionarnom stanju. U radu je također prikazana izravna usporedba odziva pojednostavljenog modela pneumatika i modela s detaljnim gaznim slojem, podvrgnutih nizu analiza, od analize kontakta između tla i pneumatika pod statičkim uvjetima opterećenja do skretanja pri kotrljanju u stacionarnom stanju

Uticaj nivoa mlečnosti na osobine plodnosti krava crno bele rase

In this study a relationship between the milk yield and following reproduction traits: number of inseminations per conception [AIS], service period [SP], age at calving [AC], calving interval [CI] and birth weight [BW] is studied. The research involved dairy cows of European type of Black and White cattle which are being intensively improved by the genes of Holstein - Friesian breed. Mean values of general average for number of inseminations per conception, service period, age at calving, calving interval and birth weight are: 2.00; 98.78; 1088.08; 376.70 and 36.40, respectively. In general, the estimated phenotypic correlations (rp) between the milk yield over standard lactations and fertility traits were positive and unfavorable, and ranged from 0.24 for the relationship between milk yield and birth weight to 0.70 for relationship between milk yield and age at calving.U radu je ispitivan odnos između prinosa mleka i sledećih osobina plodnosti: indeks osemenjavanja [IO], servis period [SP], uzrast pri teljenju [UT], međutelidbeni interval [MI] i masa teladi pri rođenju [MTR]. Ispitivanja su se odnosila na mlečne krave evropskog tipa crno-belih goveda koje se intenzivno oplemenjuju genima holštajn-frizijske rase. Za analizu je korišćen Metod najmanjih kvadrata - LSMLMW (HARVEY, 1990), fiksni model. Srednje vrednosti opšteg proseka za indeks osemenjavanja, servis period, uzrast pri teljenju, međutelidbeni interval i masu teladi pri rođenju su: 2,00; 98,78; 1088,08 ; 376,70 i 36,40, respektivno. Procenjene fenotipske korelacije (rp) između prinosa mleka i osobina plodnosti generalno su bile pozitivne i nepovoljne, i imale su vrednosti od 0,24 za odnos između prinosa mleka i masu teladi pri rođenju do 0,70 za odnos između prinosa mleka i uzrasta pri teljenju

Uticaj farme i meseca laktacije na mlečnost ovaca

The production of milk in a sheep breed households was 128.05 kg, with variations between 123.14 and 138.63 kg. Period of lactation was 165.04 days. Content of milk fat was 6.53%. There were significant differences in dependence of farms. Maximal daily production was in the first month of lactation. Milk yield was 1.046 kg. From the beginning till the end of lactation, milk yield was reduced for 0.479 kg, so at the end the yield was 0.567 kg. Content of milk fat at the first control was 5.30%, at the second, 6.23%, at the third, 6.98% and at the fourth control it was 7.62%. The influence was very significant on the daily production of milk.U ovom radu prikazani su rezultati kontrole mlečnosti kod ovaca svrljiške pramenke. Istraživanje je obavljeno na šest gazdinstava i ukupno je kontrolisano 130 grla. Na osnovu dobijenih rezultata utvrđeno je trajanje laktacionog perioda od 165,04 dana. Količina proizvedenog mleka prosečno je iznosila 128,05 kg, u kojem je bilo 6,53% mlečne masti. Podaci pokazuju da postoji vrlo značajna statistička razlika (P (lt) 0,01) u prinosu mleka između ovaca na gazdinstvu III u odnosu na II gazdinsitvo. Razlika je iznosila 15,49 kg ili 12,58%. Razlike između gazdinstava III > IV od 10,30 kg (8,03%); III > II od 9,86 kg (7,66%) bile su takođe statistički vrlo značajne (P (lt) 0,01). Prosečna dnevna mlečnost se smanjivala od prve do četvrte kontrole, tj. laktacija je imala stalni descendentni tok. Količina dnevne mlečnosti 30-tog dana laktacije tj. kod prve kontrole prosečno je iznosila 1,046 kg, druge kontrole 0,878 kg, treće 0,736 kg i četvrte 0,567 kg. Sadržaj mlečne masti u mleku se povećava od prve do četvrte kontrole. Vrednosti su bile 5,30% mlečne masti kod prve, 6,23% druge, 6,98% treće i 7,62% četvrte kontrole. Gazdinstvo tj. farma je imala značajan uticaj na ukupnu količinu namuženog mleka