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

Photoelectron Spectroscopy of Adamantane and Some Adamantanones

The photoelectron (PE) spectra of adamantane (1) , adamantanone (2), 2-noradamantanone (3), 9-noradamantanone (4), 9-homonoradamantanone (5), 4-protoadamantanone (6), 4,5-protoadamantandione (7) an:l 2,6-adamantandione (8) were recorded

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

Utjecaj mikrostrukture na proces nastajanja strugotine za konvencionalnu i polutekuću lijevanu Al-Cu leguru

For many metal alloys, the process of metal cutting is accompanied by extensive plastic deformation and fracture. To study this process, quick stop sectional samples of hypoeutectic Al-Cu alloy chip formation, either as conventionally cast alloy or as “semi solid metal” are used. The type of chip formation is classified according to crack formation mechanism and propagation. During cutting, in all specimens used, quasi-continuous chips with built-up edge (BUE) are obtained. The formation of BUE is undesirable since it is a highly deformed body with a semi stable top which periodically breaks away giving rise to poor workpiece surface quality.Za mnoge metalne legure, proces rezanja je praćen intenzivnom plastičnom deformacijom i lomom. Za istraživanje tog procesa u radu je korištena metoda brzog zaustavljanja procesa rezanja. Materijal uzorka je podeutektička Al-Cu legura, lijevana konvencionalno i kao „polu čvrsti metal“ (semi solid metal-SSM). Vrsta strugotine koja je obrazovana klasifi cirana je prema mehanizmu nastajanja i širenja pukotina. Tokom rezanja, u svim uzorcima nastajala je, kvazi-kontinuirano strugotina sa naslagama (BUE). Stvaranje BUE je nepoželjan proces, jer je to jako deformirani volumen sa polu stabilnim oblikom, koji povremeno raste i odvaja se, što dovodi do lošeg kvaliteta obrađene površine

The microstructure infl uence on the chip formation process of Al-Cu alloy cast conventionally and in semi solid state

For many metal alloys, the process of metal cutting is accompanied by extensive plastic deformation and fracture. To study this process, quick stop sectional samples of hypoeutectic Al-Cu alloy chip formation, either as conventionally cast alloy or as “semi solid metal” are used. The type of chip formation is classifi ed according to crack formation mechanism and propagation. During cutting, in all specimens used, quasi-continuous chips with built-up edge (BUE) are obtained. The formation of BUE is undesirable since it is a highly deformed body with a semi stable top which periodically breaks away giving rise to poor workpiece surface quality

Photoelectron Spectra of Lignin Model Compounds

The He I photoelectron (PE) spectra of the 77 lignin subunits were measured and arranged in classes of compounds according to the following functional groups: aldehydes, ketones, alcohols, carboxylic acids, functionalized polymethyl benzenes and miscellaneous lignin subunits. In all spectra the highest occupied molecular orbital (HOMO) was assigned to a jt-orbital

Photoelectron Spectroscopy of Adamantane and Some Adamantanones

The photoelectron (PE) spectra of adamantane (1) , adamantanone (2), 2-noradamantanone (3), 9-noradamantanone (4), 9-homonoradamantanone (5), 4-protoadamantanone (6), 4,5-protoadamantandione (7) an:l 2,6-adamantandione (8) were recorded

Chiral 1,4-Benzodiazepines. X. Further Investigations of Configurational Stability of the Chiral Centre C(3)

For various at C(3)-chiral 1,4-benzodiazepin-2-ones rate determinations of racemisation (ka.- for C(3)-0CH3 derivative ( + )-1), degenerate nucleophilic exchange (k0 - for rac. 1 and rac. 2), and solvolysis (k5 - for C(3)-hemisuccinyl derivative 4) have been performed. These investigations revealed; (a) retention of .configuration during methanolysis of ( + )-3, (b) slow racemisation of ( + )-1 during solvolytic degenerate nucleophilic substitution (kefko. - - 4), (c} no participation of SNl retentive reaction, possible via intramolecular transfer of the methoxy group within intermediary compounds 4-6, (d) thermodi:namic parameters for racemisation of ( + )-1 between 20-40 °c; liH"" = 18.0 ± 0.8 kcal/moll**, liS"" = = - 7.2 ± 2.5 e. u.*** Mechanistic scheme is offered which accounts for all experimental results. The effect of the electrocyclic equilibrium on the electronic structure of N(4) protonated benzodiazepines, and its possible consequences for their mechanisms of biological activity on the central nervous system (CNS), have briefly been discussed

Dijagnoza, anestezija i operativni zahvat kod rupture mokraćne bešike novorođene ždrebadi

This study describes methods for the diagnosis, anesthesia and operative repair in 4 neonatal foals with urinary bladder rupture. Diagnosis was based on case history, clinical signs, changes in serum chemistry analyzes (hyponatremia, hyperkalemia, hypochloremia, metabolic acidosis and increased serum creatinine and urea nitrogen levels), abdominocentesis, ultrasound and electrocardiographs. As electrolyte abnormalities and acid-base derangement can lead to the development of cardiac arrhythmia during general anesthesia, surgical treatment of urinary bladder rupture in neonatal foals should be performed when the animal's condition has been stabilized. This includes infusion of physiological saline solution, 5 % glucose infusion with insulin (0.1U/kg) and 1.4% sodiumdrogencarbonate.Ova studija opsuje dijagnostikovanje, anesteziju i operativni tretman pri rupturi mokraćne bešike novorođene ždrebadi. Dijagnoza je zasnovana na istoriji bolesti, kliničkim simptomima, promenama u serumu ustanovljenim biohemijskim analizama (hiponatrijemija, hipokalijemija, hipohloremija, metabolička acidoza sa porastom nivoa serumskog kreatinina i ureje), abdominocintezi, ultrazvuku i elektrokardiografiji. Kao što poremećaji elektrolita i acido-bazne ravnoteže mogu dovesti do pojave srčane aritmije u toku opšte anestezije, hirurški tretman rupture bešike kod novorođene ždrebadi može biti primenjen kada je stabilizovano zdravstveno stanje životinje. Ovo uključuje infuziju fiziološkog rastvora, 5% glukoze sa insulinom (0,1 U/kg) i 1,4% Na-bikarbonat