Modeling profile and kinematic analysis of two circular-arc cams

The paper presents a methodology for modeling profile of two circular-arc cams, which is based on the application of homogeneous coordinate transformation method. Analytical expressions that allow complete determining of all design parameters and coordinates of all the points of two circular-arc cams profile are defined. Also, analytical expressions for determining the kinematic performance such as displacement, velocity, acceleration and jerk are derived. The defined methodology is applied on concrete examples for which the analysis of the kinematic performance is also performed. Additionally, it is shown that a proper choice of the design parameters can significantly affect the improvement of the kinematic performance, especially the reduction of jerk as one of the most unfavorable occurrences in these mechanisms. The given methodology allows very efficient determination of all input data for parametric modeling and production of two circular-arc cams on numerical machines. This approach allows the fulfillment of one of the most important requirements of modern production–reduction of time necessary for design and manufacturing which causes reduction of costs.     

Statistical analysis of the characteristics of some basic mass-produced passive electrical circuits used in measurements

Statistical properties of some basic mass-produced passive electrical circuits used in measurements are analyzed in this paper, using methods for expressing measurement uncertainty of indirectly measured quantities. The focus of this paper is on electrical circuits whose defining parameters are obtained as non-linear functions of component parameters. Variants of voltage divider and Wheatstone bridge circuits significant for measurement practice are investigated in detail. Even if distributions with symmetrical probability density functions (PDFs), such as uniform or normal, are adopted for the parameters of the components comprising a circuit, non-linearity of the circuit function gives rise to asymmetry in the PDF of the circuit’s parameter. The asymmetry of the PDF causes the mean and the nominal value of the circuit parameter to differ.     

Prediction of brake friction materials recovery performance using artificial neural networks

The brake friction materials in an automotive brake system are considered as one of the key components for overall braking performance of a vehicle. The sensitivity of friction material performance and accordingly brake performance, versus different operating regimes, has always been an important aspect of its functioning. In this paper, the influences not only on the brake operation conditions but also on the formulation and manufacturing conditions of friction materials have been investigated regarding friction materials recovery performance by means of artificial neural networks. A new neural network model of friction material recovery performance, trained by the Bayesian Regulation algorithm, has been developed.     

Authentication study of volatile flavour compounds composition in Slavonian traditional dry fermented salami “kulen”

Volatiles from famous Slavonian salami “kulen” were isolated by nitrogen purge and steam distillation (NPSD) and analysed, for the first time, by gas chromatography and mass spectrometry (GC and GC–MS). In all, 119 organic compounds were identified that originated from lipid oxidation, amino acid degradation, smoke treatment and added spices with different distribution among NPSD traps. NPSD method enabled comprehensive profiling with almost exclusive distribution of several major compounds in particular trap with little or no interference from abundant lipid constituents in the samples. The major identified flavour important compounds were methylphenols, methoxyphenols, organosulphur compounds (diallyl sulphide, diallyl disulphide, methylallyl disulphide, diallyl trisulphide and methional) and several derivatives of 2-cyclopenten-1-one such as ethyl cyclotene. Non-important flavour constituents such as high-molecular fatty acids, alcohols and aldehydes were also present among abundant compounds. General trends for possible discrimination of “kulen” volatiles profile among other European salami volatiles were noticed (lower amount of terpenes and higher percentages of diallyl sulphide, methoxyphenols, methylphenols and 2-cyclopenten-1-one derivatives).     

Independent publications from Serbia in the Science Citation Index Expanded: a bibliometric analysis

This paper presents a bibliometric analysis of articles from the Republic of Serbia in the period 2006–2012 that are indexed in the Thomson Reuters SCI-EXPANDED database. The Republic of Serbia is a small country in Europe with about seven million citizens that became an independent country in 2006. Since 2006, Serbian science has achieved some recognition. Analysis included 14,293 articles with authors all from Serbia. Distribution of published articles in the Web of Science categories, journals, scientific-research institutions and researchers were analysed. Most cited independent research articles from Serbia were also analysed. The Y-index indicator for rating the productivity of researchers and institutions was used. This indicator takes into account the contribution of the researcher to the published results. The results showed that the productivity of articles from Serbia is significant compared to neighbouring Serbian countries, taking into account the number of researchers in these countries, their GDPs and the percentages of GDPs spent on research.     

Synthesis of Lead Nickel Niobate–Lead Zirconate Titanate Solid Solutions by a B-site Precursor Method

A modified processing method for lead nickel niobate–lead zirconate titanate (Pb(Ni_1/3Nb_2/3)O₃–Pb(Zr,Ti)O₃, PNN–PZT) solid solutions is presented. This method is based on the high-temperature synthesis of a precursor that contains all the B-site cations (Ti, Zr, Ni, and Nb). This synthesis yields a diphasic mixture that contains a ZrTiO₄-like phase and a rutile-like phase. Both phases exhibit a cationic valence of 4; thus, it is concluded that the mixing of Ni and Nb cations is adequate for the preparation of PNN–PZT solid solutions. Indeed, a pure perovskite phase has been obtained after calcination with lead oxide for compositions that contain 40 and 50 mol% PNN. Moreover, their electromechanical properties have been shown to be superior to values reported for standard columbite routes. This conclusion has been interpreted in terms of enhanced chemical homogeneity.     

Adopting Software Engineering Trends in AI

Designing and developing reliable, robust, well-architected, and easy-to-extend software applications or tools in any field requires conformance to sound principles and rules of software engineering. Intelligent systems, especially AI development tools, are no exception. Although AI has always been a wellspring of ideas that software engineering has later adopted, most of its gems remain buried in laboratories, available only to a few AI practitioners. This paper believes that AI tools should be integrated with mainstream SE tools and thus become more widely known and used. To that end, this paper presents the development of Air, an integrated AI development environment based on model-driven-architecture concepts. Using the philosophy of MDA in Air, familiar and mainstream software technologies are used and expanded with new functionalities