The response surface methodology was employed to make mathematical modeling and optimization of the temperature and pressure for centrifugal compressor. ProSimulator software was used for simulation of process parameter mainly temperature (x) and pressure (y). We considered a polynomial regression model equation between independent variable (x) and dependent variable (y). The simulation parameter revealed that the modeled values were in good agreement with simulated ones.

This paper examines the prospects of using semiconductor layered A3B6 type-photovoltaic cells and the photoresistors as receptors for quantitative and qualitative measurements of carbon oxides. Carbon compounds in gaseous state form absorption bands of electromagnetic radiation in a wide range of spectrum (200-100 000 cm-1). The light absorbed or emitted in these bands at the excitations with ionizing radiation (X, Y) or strong electric fields contain direct information about the concentration of these molecules. The frequencies that correspond to maxima of these bands are characteristic parameters of absorbing molecules. Fundamental absorption bands of CO, CO2 and NC have the edge of band at the border of ultraviolet-vacuum, while the emission bands d cover their full range of wave numbers from 45000 cm-1 to 10000 cm-1. Two types of radiation receptors from lamellar semiconductor type photosensitive in this spectral range are studied.

The trajectories described by the seeds on the planned double inclined surface play an important role in sorting seeds by density on the vibrating tables. The article develops the mathematical models of the particles trajectory supported by friction on double inclined plane surfaces subject to a motion by rectilinear translation harmonic oscillation and it emphasizes the difference between the particles trajectory with various friction coefficients. The values of such friction coefficients are in accordance with the variable density of the seeds which thus entails different places of seeds collection by their density on one of the sides of the surface.

This article tries to present the basic elements of the main guidelines, international standards and methodologies (methods) used in project management. In this category we include: the PMBOKRGuide (elaborated by the Project Management Institute), the PRINCE method (elaborated by the British Office of Government Commerce), the ISO 21500:2012 standard (elaborated by the International Organization for Standardization) etc. At the basis of these guidelines, standards and methodologies stay a great practice experience. Depending on the particularity and type of project, of management philosophy and culture of the organization that runs the project, we can choose to apply a certain guide, standard or methodologies (methods). The stated goal of these guidelines, standards and methodologies (methods) is to provide an optimum framework, the best practice for manage project to success. Applying these guidelines, standards and methodologies (methods) may be prerequisite project success, being a necessary but not always sufficient.

This paper evaluates the impact caused by inertia force of beam with non-uniform mass distribution. The impact is made by non-uniform beam falling on supports. Then, stresses of this model are analysed and optimized by using position of the supporting forces, mass distribution and convenient geometry. Results of this study, present the solutions for better design of the beam and having the highest resistance for it, and also have some suggestions for better geometry until the beam get stronger. In this paper, useful relations between bending stress on the beam due to inertia shock, mass distribution and position of supporting forces are demonstrated. The study reveals some interesting findings related to the best bar configuration in terms of geometrical design, design of supports location, mass distribution and use of multi-material components. The studied problem takes place in many of the mechanical systems such as exhaust and suspension systems and etc.

The aim of this research is to ascertain the functionality and practical applicability of a developed generalized model for investigation of the energy efficiency of mechanical handling machines and systems in its specific application for the continuous-transport individual machines and systems. A typical industrial system for transportation and fragmentation of rock materials is chosen as an investigation object. The investigation procedure is entirely based on the model being validated. The obtained results demonstrate the presence of possibilities for practical application of the model and reveal a low energy-efficiency level. If the belt conveyors' load is optimal, the electric energy consumption of the site can be decreased by 45 % as the potential energy losses can be reduced to 0.66 % in case of reconstruction.

The aim of the current work was to analyse the influence of the process parameters (tool diameter, size of the vertical step of tool, feed rate and spindle speed) on the quality of the processed surface, expressed in terms of roughness and macrostructure in the case of parts processed by single point incremental forming. The analysis was made on A1050 aluminium metal sheets. The obtained results revealed that the process parameters influence differently the surface quality, the worst influence being exerted by the increase of the vertical step of tool.

Polymeric materials reprocessing leads to modification of polymeric materials flow properties. In this paper there are summarized the correlations n-y(obtained from previous experimental research), for several types of virgin and reprocessed polymeric materials, comparatively presented. Models and simulations were performed for the extruding polymeric materials reprocessing, the screw functional feature Q(p)-with and without considering the leaks over the screw helix flight tip-to assess changes in the performances.

Operators worldwide are using hazardous substances in the production process and after the completion of production processes, those substances can cause major accidents with serious consequences on the health and safety of people and the environment. This paper describes some of the methods of risk analysis in plants who use hazardous substances in the production process, in order to identify a method combined-complete, to provide the data needed to calculate the effects of chemical accidents and emergency planning.

This paper presents the mathematical expressions for calculating the temperatures between the layers of a plan, tubular or spherical composite, by natural or forced conduction and convection or under the influence of stationary heat flow. Here there are taken into account two possibilities of contact between the layers: one is the perfect contact or the other acknowledges the existence of casual imperfections. The expressions also take into consideration the influence of added protection on the wall surface or the possible deposits of solids materials that can occur during the operation of the structure.

The declining water quality in Sriwijaya University has been caused by the presence of heavy metal contents such as Iron (Fe) and Zinc (Zn) in the treatment and distribution of water. A simple method is proposed in this work to minimize the heavy metal content in water by using filtration technology. This research was carried out using ceramic filter made of 77.5% natural clay, 20% fly ash, and 2.5% iron powder. The results showed an increase in the quality of raw water that is in accordance with the requirement of drinking water standard. The rejection percentage of TDS, Iron (Fe) and Zinc (Zn) content in feed water tended to be high and met the regulation number 492/MENKES/PER/IV/2010 for standards of drinking water in Indonesia.