Surface roughness modeling of CBN hard steel turning

Study in the paper investigate the influence of the cutting conditions parameters on surface roughness parameters during turning of hard steel with cubic boron nitrite cutting tool insert. For the modeling of surface roughness parameters was used central compositional design of experiment and artificial neural network as well. The values of surface roughness parameters Average mean arithmetic surface roughness (Ra) and Maximal surface roughness (Rmax) were predicted by this two-modeling methodology and determined models were then compared. The results showed that the proposed systems can significantly increase the accuracy of the product profile when compared to the conventional approaches. The results indicate that the design of experiments modeling technique and artificial neural network can be effectively used for the prediction of the surface roughness parameters of hard steel and determined significantly influential cutting conditions parameters

Evaluation of Pyrocondensates as a Polymerization Raw Material

Two pyrocondensate samples were examined in order to evaluate them as polymerization raw materials. The components were identified or undoubtedly characterized by means of mass spectral data taken by GC-MS and by gas chromatography retention data. Quantitative analysis of pyrocondensates and the residues which remained after cationic, thermal or free radical polymerizations was made by high resolution gas chromatography, Pyrocondensates contained mainly alkyl and alkenyl substituted benzenes and fused ring compounds. In one sample bicyclic components, with cyelopentadiene and cyclohexadiene as constitutive bases, were found. As the samples contained a fairly high portion of components able to polymerize, they were found to be of interest for polymerization into resins. Polimerization yields of the whole sample and of a single reactive component depended on the type of polymerization. Cationic polymerization gave the highest and polymerization by peroxides the lowest polymerization yield in the whole sample. Alkenylbenzenes and indenes reacted in the cationic polymerization better than in the other two kinds of polymerization, while bicyeles gave the best yield in the polymerization of thermal type

Investigations of Tll Suspensions

Thallous iodide suspensions were obtained by direct mixing of TlN03 and Na! solutions. The amount of TH was kept constant in the systems, while the concentrations of Na! (in excess), laurylamine nitrate (LAN) or myristylamine nitrate (MAN) were varied. Tyndallometric values were recorded as the function of Na!, LAN, and MAN concentrations respectively, for suspensions aged for various times. Particle sizes of differently aged TH in \u27Suspensions containing Na! and Eu(N03)a in solution were determined. Tyndal.:. lometry and electronmicroscopy showed fast particle growth of TH in suspension. After about 10 minutes the TH particle grew up to 1.3 μ. The zero point of charge, determined by microelectrophoresis, was attained at 0.001-0.005 M Na! and 0.0001-0.0005 M LAN depending on the conditions under which the system had been prepared. The results of radiometrically recorded adsorption- desorption equilibria show a constant increase of the adsorption capacity as the electrolyte concentration increases

Investigations of Tll Suspensions

Thallous iodide suspensions were obtained by direct mixing of TlN03 and Na! solutions. The amount of TH was kept constant in the systems, while the concentrations of Na! (in excess), laurylamine nitrate (LAN) or myristylamine nitrate (MAN) were varied. Tyndallometric values were recorded as the function of Na!, LAN, and MAN concentrations respectively, for suspensions aged for various times. Particle sizes of differently aged TH in \u27Suspensions containing Na! and Eu(N03)a in solution were determined. Tyndal.:. lometry and electronmicroscopy showed fast particle growth of TH in suspension. After about 10 minutes the TH particle grew up to 1.3 μ. The zero point of charge, determined by microelectrophoresis, was attained at 0.001-0.005 M Na! and 0.0001-0.0005 M LAN depending on the conditions under which the system had been prepared. The results of radiometrically recorded adsorption- desorption equilibria show a constant increase of the adsorption capacity as the electrolyte concentration increases

Promene EKG tokom hiperinfuzione terapije konja sa hroničnim opstruktivnim oboljenjima

This study describes investigations into the electrocardiogram changes in 27 horses with chronic obstructive pulmonary disease (COPD), during hyperinfusion therapy with isotonic saline solution. Immediately after hyperinfusion therapy the equine ECG showed a temporary sinus tachycardia without atrial and ventricular rhythm disturbances. After infusion a highly significant shortening of the PQ-, QT and TP-intervals was observed. There was a positive correlation between the RR-interval and the duration of the PQ- and QT-intervals, but not with the duration of the P-, QRS- and T-waves.Ova studija opisuje ispitivanja promena u elektrokardiogramu 27 konja sa hroničnim plućnim oboljenjima (COPD) utoku hiperinfuzione terapije izotoničnim rastvorom soli. Neposredno posle hiperinfuzione terapije, EKG konja je pokazivao postojanje povremene sinusne tahikardije bez poremećaja ritma rada pretkomora i komora. Posle infuzije zapaženo je veoma izraženo skraćenje PQ, QT, TP intervala. Izražena je povezanost između RR intervala i trajanja PQ i QT intervala, ali ne i sa pojavom P, QRS i T talasa

Relationship Between Attrition Faces and Signs of TMD

Smatra se da su brusne fasete znak funkcijskih i parafunkcijskih aktivnosti, te ih nalazimo na okluzalnim i incizalnim plohama zuba obično kao posljedicu procesa atricije. Brusne fasete razlikuju se opsegom i pozicijom na zubima. Bruksizam, kao parafunkcijska aktivnost, smatra se jednim od etioloških čimbenika za nastanak disfunkcije stomatognatoga sustava. Cilj rada bio je istražiti moguću povezanost između pojavnosti brusnih faseta, kao znak bruksizma, i znakova temporomandibularne disfunkcije. Temeljem nalaza brusnih faseta nakon izvršena kliničkog pregleda izdvojeno je 100 ispitanika, određenih za daljnje istraživanje. Opsežnost brusnih faseta procjenjivana je modificiranim indeksom Pullingera i Seligmana: stupanj 0 = nema vidljive atricije; 1 = minimalna atricija kvržica ili incizalnih bridova (u caklini); 2 = fasete usporedne s normalnim područjima kontura ploha (caklina); 3 = zamjetna zaravnjenja kvržica ili incizalnih bridova (caklina); 4 = potpuni gubitak kontura ploha/bridova i ekspozicija dentina do polovice visine nekadašnje krune zuba; 5 = potpuni gubitak kontura i ekspozicija dentina za više od polovice nekadašnje krune zuba. Svi ispitanici podvrgnuti su kliničkim ispitivanjima kako bi se utvrdilo postojanja znakova TMD-a. Rezultati su pokazali da ne postoji statistički znatna povezanost između znakova TMD-a i pojavnosti brusnih faseta te ni između znakova TMD-a i opsežnosti brusnih faseta. Rezultati ovoga istraživanja slažu se s ostalim recentnim studijama da brusne fasete nisu pouzdan pokazatelj za procjenjvanje funkcijskog stanja stomatognatoga sustava. Ovim istraživanjem nije utvrđeno postojanje povezanosti između pojavnosti brusnih faseta i znakova temporomandibularne disfunkcije.Attrition faces are usually seen on the occlusal or incisal surfaces of teeth worn by attrition. They are considered to be a sign of functional and parafunctional activities, and can differ by wideness and position on the teeth. Bruxizm, as a parafunctional activity, is considered to be a risk factor for dysfunction of the masticatory system. The aim of the study was to investigate the possible relationship between attritional faces, as a sign of bruxizm, and signs of temporomandibular dysfunction. By clinical examination, a group of 100 subjects was selected for trial, based on findings of attritional faces. The severity of attrition faces was quantified on a fivepoint scale ( modified assessment for determination of incisal tooth wear according to Pullinger and Seligman: 0 = no visible tooth wear; 1 = minimal wear of cusps or incisal tips (enamel); 2 = faces parallel to normal planes of contour (enamel); 3 = noticeable flattening of cusp or incisal edges (enamel); 4 = total loss of contour and dental exposure when identifiable (dentin exposure up to half of former crown of tooth): 5 = total loss of contour and dental exposure over half of former crown of tooth). Selected subjects were then examined by standard procedure to investigate the presence of TMD signs. Results showed that there was no statistical significance between signs of TMD and presence of attrition faces, and neither between signs of TMD and severity of attrition faces. Results of this study are compatible with other recent investigations, which show that attrition faces are not a reliable sign for assessing the functional status of the masticatory system. According to this investigation there is no association between attrition faces and signs of temporomandibular dysfunction

A blind H i survey in the Canes Venatici region

We have carried out a blind H i survey using the Westerbork Synthesis Radio Telescope to make an inventory of objects with small H i masses (between 106 and 108 M⊙) and to constrain the low-mass end of the H i mass function. The survey has been conducted in a part of the volume containing the nearby Canes Venatici groups of galaxies. The surveyed region covers an area on the sky of about 86 deg2 and a range in velocity from about −450 to about 1330 km s−1. We find 70 sources in the survey by applying an automated searching algorithm. Two of the detections have not been catalogued previously, but they can be assigned an optical counterpart, based on visual inspection of the second-generation Digital Sky Survey images. Only one of the H i detections is without an optical counterpart. This object is detected in the vicinity of NGC 4822, and it has been already detected in previous H i studies. 19 of the objects have been detected for the first time in the 21-cm emission line in this survey. The distribution of the H i properties of our detections confirms our ability to find low-mass objects. 86 per cent of the detections have profile widths less than 130 km s−1, and they can be considered dwarf galaxy candidates. The H i fluxes measured imply that this survey goes about 10 times deeper than any previous blind H i survey. The H i mass function and the optical properties of the detected sources will be discussed in future paper

Stanje površinskog sloja materijala obratka kod visokoučinskog brušenja

This paper focuses on the development of high temperatures in the cutting zone during high performance grinding. In order to identify the influence of grinding temperature on surface integrity, temperatures were measured in the workpiece surface layer under different machining conditions. Beside this, under the same conditions, the surface layer properties of the workpiece material were determined through metallographic examination. Microstructureand microhardness of the workpiece surface layer, as well as the burned surfaces and microcracks phenomena were investigated. The conducted experimental investigations allow the surface layer properties of the workpiece material in high performance grinding to be defined.U članku se ukazuje na pojavu visokih temperatura u zoni rezanja pri visokoučinskom brušenju. Da bi se ustanovio utjecaj temperature brušenja na kvalitet obrađene površine, izmjerene su temperature u površinskom sloju materijala obratka pri različitim uvjetima obrade. Ujedno je pri istim uvjetima obrade određeno stanje površinskog sloja materijala obratka metalografskim ispitivanjima. Ispitane su mikrostruktura i mikrotvrdoća površinskog sloja obratka i pojava nagorjelih površina i mikropukotina. Izvedena eksperimentalna istraživanja defi niraju stanje površinskog sloja materijala obratka kod visokoučinskog brušenja

Cognitive cultural models and politeness principles in academic discourse: Serbia and Spain as case studies Когнитивные культурные модели и принципы вежливости в академическом дискурсе: тематические исследования на примере Сербии и Испании Modelos culturales cognitivos y principios de cortesía en discurso académico: Serbia y España como estudios de caso

Oвa докторскa дисертацијa бави се когнитивним културним моделима у спрези са принципима учтивости у академском дискурсу у српској и шпанској академској заједници. Реч је о интердисциплинарном истраживању из перспективе критичке социолингвистике, когнитивне социолингвистике, когнитивне антропологије и критичке анализе дискурса. Циљ рада био је да се испита, упореди и прикаже дискурс између професора Универзитетâ у Београду/Крагујевцу/Гранади и студената докторских студија. Специфични циљеви били су: препознати и тумачити моделе комуникације у обе земље, упоредити когнитивне културне моделе и испитати како учесници виде учтивост. Крајњи циљ био је да се однос моћи у дискурсу аргументује као однос сарадње. Примењена је квалитативна истраживачка метода, студија случаја, док су методе прикупљања података биле опсервацијe, полуструктурирани интервјуи и критичка анализа академског дискурса. Корпус су чинили сви прикупљени записи током опсервација, примери из интервјуа и интерпретација академског дискурса. Анализа резултата указала је на висок степен подударања између заједницâ. У професорском дискурсу заступљен је когнитивни културни модел модернизације, без строгих правила понашања. Традиционални когнитивни културни модел изражен је код српских студената, док код шпанских преовладава модел модернизације. Когнитивни културни модел академије једнако поседују сви, као и модел који обједињује аспекте више модела дефинисан као когнитивни културни модел индивидуалног испољавања. Општи закључак је да нема великих ни суштинских разлика, што показује да су у оквиру обе академске заједнице присутни исти или веома слични когнитивни културни модели. Академски дискурс одвија се на исти начин или уз извесне разлике, при чему влада принцип учтиве сарадње између саговорника.This doctoral dissertation deals with cognitive cultural models in connection with the politeness principles in academic discourse in the Serbian and Spanish academic communities. It is an interdisciplinary research from the perspective of critical sociolinguistics, cognitive sociolinguistics, cognitive anthropology and critical discourse analysis. The aim of the paper was to examine, compare and present a discourse between professors at the Universities of Belgrade/Kragujevac/Granada and PhD students. Specific goals were to: identify and interpret communication models in both countries, compare cognitive cultural models and examine how the participants perceive politeness. The ultimate goal was to argue the power in discourse as a collaboration relationship. A qualitative research method was used, a case study, while the methods used to collect data were observations, semi-structured interviews and critical analysis of academic discourse. The corpus consisted of all collected notes during observations, interview examples and the interpretation of the academic discourse. The analysis of the results has indicated a high degree of compatibility between the communities. In the professor's discourse is presented a cognitive cultural model of modernization, without strict rules of behavior. The traditional cognitive cultural model is present in the case of Serbian students, while the modernization model is predominant among the Spanish ones. The cognitive cultural model of academia is equally shared by everyone, as is a model that integrates aspects of multiple models defined as a cognitive cultural model of individual expression. The general conclusion is that there are neither major nor essential differences, which indicates that the same or very similar cognitive cultural models are present within both academic communities. Academic discourse takes place in the same way or with certain differences, whereby the principle of polite cooperation is dominant between the interlocutors