Global Journal of Technology and Optimization

Fine dust, especially those fractions below 10 and 2.5 microns can cause serious heart and respiratory disease and stringently requires effective pollutant standards and methods for their reduction. Therefore stricter emission European Union regulations [1, 2] were recently established, in order to improve the fine dust situation of the ambient air in Europe. Nowadays among different technical separation devices, filtering, regenerate dust separators are the most suitable ones to meet very low dust emission concentrations of industrial exhaust gases. But the disadvantage of this separator is the relative high pressure drop and sometimes a premature filter media clogging, which requires its costly replacement. In order to minimise this disadvantage, suitable design and standard laboratory test methods are in use. E.g. in Europe a German guideline (VDI 3926) [2] exists, by which in laboratory test runs optimal filter media can be evaluated. The problem is that within these test methods a so called aging procedure is included. The clogging behaviour of the aging procedure was basically investigated in this paper and a new test procedure for comparing different filter media with respect to the aging was developed

Iterative clustering algorithms commonly do not lead to optimal cluster solutions. Partitions that are generated by these algorithms are known to be sensitive to the initial partitions that are fed as an input parameter. A “good” selection of initial partitions is an essential clustering problem. In this paper we introduce a new method for constructing the initial partitions set to be used by the Expectation-Maximization clustering algorithm (EM algorithm). Our approach follows ideas from the Cross- Entropy method. We use a sample clustering provided by means of the EM algorithm as an alternative for the simulation phase of the Cross-Entropy method. Experimental results reflect a good performance with respect to the offered method.

The aim of the work is to develop a method of simple characterization of solid fuels combustion in fixed bed, which would be useful for CFD modelling. In this work, the measurements were performed in a test rig, where a combustion front propagates against the airflow. Concentrations of flue gas species were registered at the exit of a fixed bed reactor and the temperature of burning coal was measured in selected points of the reactor as functions of time. Furthermore, developed functions were applied for defining the boundary conditions at the interface between the fixed bed and gas phase using FLUENT. The simulations of a domestic boiler have been done and the relative effects of different factors in CFD code were evaluated by sensitivity analysis

Solar photovoltaic (PV) electrification is an important renewable energy source. The electric which is converted directly from solar irradiation via PV panel is not steady due to different solar intensity. To maximize the PV panel output power, perturb and observe (P&O) maximum power point tracking (MPPT) has been implemented into the PV system. Through a buck-boost DC-DC converter, MPPT is able to vary the PV operating voltage and search for the maximum power that the PV panel can produce. The implementation of fuzzy logic is proposed in this paper. Based on the change of power, and change of power with respect to change of voltage, fuzzy determines the size of the perturbed voltage. In this paper, the performance of fuzzy logic with various membership functions (MFs) is tested to optimize the MPPT. Fuzzy logic can facilitate the tracking of maximum power faster and minimize the voltage variation. Simulation results show that the performance of fuzzy based MPPT with five membership functions (5MFs) is better than fuzzy based MPPT with three membership functions (3MFs), followed by the conventional P&O MPPT.

This paper presents the new integrated monitoring system for high voltage electric power substation system. The substation has a crucial function to maintain the reliability and to keep the quality of an electric power transmission system. On the other hand, the exposure to high voltage environment may also be able to cause risk to human health. Therefore an integrated monitoring system is crucial to be implemented for easy monitoring and controlling the substation while minimizing interaction of human to the substation devices. All the substation devices conditions are displayed integratedly in Graphical User Interface (GUI) developed using LabVIEW software. The developed display contains several windows and said window display. As a result, the parameters of the substation devices such as: frequency, voltage, load impedance, reluctance, oil level, temperature, cooling condition, power and protection system are successful displayed and monitored.

This paper presents the new integrated monitoring system for high voltage electric power substation system. The substation has a crucial function to maintain the reliability and to keep the quality of an electric power transmission system. On the other hand, the exposure to high voltage environment may also be able to cause risk to human health. Therefore an integrated monitoring system is crucial to be implemented for easy monitoring and controlling the substation while minimizing interaction of human to the substation devices. All the substation devices conditions are displayed integratedly in Graphical User Interface (GUI) developed using LabVIEW software. The developed display contains several windows and said window display. As a result, the parameters of the substation devices such as: frequency, voltage, load impedance, reluctance, oil level, temperature, cooling condition, power and protection system are successful displayed and monitored.

This article deals with combined production of heat and electricity for small premises, such as households, where energy consumption is around few kilowatts. This proposal of micro cogeneration unit uses as a heat source an automatic burner for combustion of wood pellets. Construction of an equipment for the heat transport can be designed using different basic ways of heat transfer. Electricity is produced by the two-stroke steam engine and the generator.

This paper proposes the applications of non-traditional stochastic optimization techniques as real coded genetic algorithm namely ”LXPM” and Differential Evolution(DE) for determination of optimal machining conditions for turning process on Computer Numerically Controlled (CNC) machines. The problem, discussed in the present study comprises several nonlinear constraints with an optimum criteria based on minimizing total production time that affects the production rate as well. The various constraints arise due to restricted machining features and are imposed on cutting force, power, tool-chip interface temperature and surface. The determination of optimal cutting parameters has significant importance for economic machining and plays an important role in reducing machining errors as tool breakage, tool wear, tool chatter etc. as well. The performances of employed heuristics are compared with several other optimization methods available in literature. The computational results demonstrate convincingly, the reliability and efficiency of considered methods for predicting optimal machining conditions for achieving the desired goal.

A two-colored digraph D(2) is a digraph D whose each of its arcs is colored by either red or blue. A two-colored digraph D(2) is primitive provided that there is a positive integer h+k such that any pair of vertices in D(2) can be connected by a walk of length h+k consisting of h red arcs and k blue arcs. The smallest of such positive integer h+k is the exponent of D(2) and is denoted by exp(D(2)). The exponent of a vertex v in a two-colored digraph D(2) is the smallest positive integer s+t such that for each vertex x in D(2) there is a walk of length s+t consisting of s red arcs and t blue arcs. In this paper we discuss the vertex exponents of a primitive twocolored extremal ministrong digraph D(2) on n vertices. If D(2) has one blue arc, we show that the exponents of vertices of D(2) lie on [n2 – 5n + 8, n2 – 3n + 1]. If D(2) has two blue arcs, we show that the exponents of vertices in D(2) lie on [n2 – 4n + 4, n2 – n].

This article describes the acquisition of low potential of geothermal energy with vertical ground heat exchangers. This system will be part of the device (simulator) for the transport of low-potential heat. This facility will include U-tube with forced circulation and heat pipes, through which the phase transition in evaporating and condensing section of the tube at temperatures below 0° C will receive low potential energy. The device thus allows the development of research activities in the verified production technology heat pipe suitable for the use of lowpotential heat of the earth in a laboratory environment. The content of the paper is the structural design of these devices. The role of the individual components of the device is to allow research thermo-kinetic parameters of transport of heat from the rocks to heat the carrier to transport simulator for low-potential heat. The device allows the physical modeling of heat flow from the rock into the heat transfer fluid.

Wireless sensor networks (WSN) are an increasingly attractive means to bridge the gap between the physical and virtual world. WSNs are envisioned to be used to fulfill complex monitoring tasks. Space and time play a crucial role in wireless sensor networks, since sensor nodes are used to collaboratively monitor physical phenomena and their space-time properties. A number of techniques and distributed algorithms for location estimation and time synchronization have been developed specifically for sensor networks. Time synchronization is a crucial component of WSNs. Time synchronization schemes developed for traditional networks are ill-suited for WSNs and more appropriate approaches should be suggested. There are many similarities in space and time domains. This affects the location estimation and time synchronization, ranging from applications and requirements to basic approaches and concrete algorithmic techniques. The purpose of this paper is to make this close affinity explicit in order to further a better understanding and improving both domains.