A new wireless asynchronous data communications module for industrial applications

All the sensors such as temperature, humidity, and pressure used in industry provide analog outputs as inputs for their control units. Wireless transmission of the data has advantages on wired transmission such as USB port, parallel port and serial port and therefore has great importance for industrial applications. In this work, a new wireless asynchronous data communications module has been developed to send the earth magnetic field data around a ferromagnetic material detected by a KMZ51 AMR sensor. The transmitter module transmits the analog data obtained from a source to a computer environment where they are stored and then presented in a graphical form. In this design, an amplitude shift keying (ASK) transceiver working at the frequency of 433.92 MHz which is a frequency inside the so called Industrial Scientific Medical band (ISM band) used for wireless communications. The analog data first fed into a 10-bit ADC controlled by a PIC microcontroller and then the digital data is sent to the transmitter. A preamble bit string is added in front of the data bits and another bit string for achieving synchronization and determination the start of the data is used. The data arriving at the receiver is taken by the microcontroller and sent to a LCD display as well as the serial port of a computer where it is written in a text file. A Visual Basic based graphics interface is designed to receive, store and present the data in the form of graphical shapes. In the paper, all the work has been explained in detail.     

Comparison of open and closed circuit HPGR application on dry grinding circuit performance

A conventional cement grinding circuit is composed of a two compartment tube mill, a mill filter which collects the fine material inside the mill and a dynamic air separator where final product with required fineness is collected. In general the material fed to the circuit has a top size of 50 mm which is very coarse for the ball mill. For this purpose, later in 1980s, high pressure grinding rolls (HPGR) has found applications as a pregrinder which increased throughput of the grinding circuit at the same fineness.In early applications, HPGR was operated in open circuit. But later as the operating principle of the equipment based on the compression, some portion of the HPGR discharge recycled back to improve efficiency of the mill or operated closed circuit with classifiers. Within this study effect of open and closed circuit HPGR applications on dry grinding circuit performance was examined. For this purpose sampling studies around three different cement grinding circuit were completed. In the first study, a circuit including open circuit HPGR, ball mill and air separator was sampled and chosen as the basic condition. As the final product size distribution is important for grinding circuit, model structure of each equipment was developed. The second and third surveys were carried out around closed circuit HPGR operation with V and VSK separator to develop models for the separators. Finally the separator models were used in basic condition to simulate closed circuit HPGR application.It was understood from the studies that closed circuit HPGR operation improved the overall circuit efficiency at the same final product fineness by reducing the specific energy consumption.     

Sustainable energy production and consumption in Turkey: A review

In this century, energy has been the driving force of the global economy and it will, for sure, continue to be one of the most important element for the sustainable socio-economic development for the coming centuries. Therefore, energy producers and governors have a vital duty to provide enough energy in good quality continuously with low cost for the sustainable development. The subject of energy production and energy politics in Turkey generally comes at first privilege. Ahead of the 21st century, Turkish energy diplomacy started to affect the future course of Turkey’s relations with the Eurasian countries as well as the Western countries. This paper describes energy production and consumption strategies in Turkey and criticizes Turkish energy policies. If the present pattern of energy production and consumption in Turkey is maintained, there will be serious problems to meet future energy demands due to shortages of resources and low financial inputs, combined with the environmental care for the country. As a result, major components of Turkey’s strategy for sustainable development should include changing the present energy production and consumption patterns, expanding energy sources and the structure of power production, and creating an energy structure that is less or not at all risky to the environment.     

An optimal policy for competitive processing of high- and low-priority arrivals

We consider two mutually independent traffic streams whose arrivals are stored in an infinite capacity buffer. The two arrival traffics are modelled by renewal processes and are competing for service by a single processor, where one of the processes requires a strict upper bound on the total delay per arrival. It is assumed that the processing per arrival, for both processes, is a constant; the value of this constant is different for each of the two traffic streams. Given the above model, we consider policies that operate in a non-interruptive mode. We first find the optimal scheduling policy, which attains throughput one and minimizes the expected delays of both traffic streams. The delays induced by the latter policy are analysed via a methodology based on the regenerative theorem. The theoretical results are supported by numerical examples.     

Realization of Current-Mode Third Order Butterworth Filters Employing Equal Valued Passive Elements and Unity Gain Buffers

This paper describes current-mode third-order Butterworth filter topologies realized with unity gain active elements and minimum number of passive components. All capacitors and resistors are equal valued. The core of the circuit realizes HP, BP and LP functions easily. The filter exhibits high output impedance. Experimental results are included to verify theory.     

An experimental investigation on frictional behavior of statically loaded micro-grooved journal bearing

Performances of plain and micro-grooved engine journal bearings were investigated in this study. Numerous experiments were performed under different static loads by using the purpose-built journal bearing test rig. Micro-grooves were made by cutting micro-channels both around and across the engine journal bearing surfaces. Stribeck curves for the micro-grooved and the plain journal bearings were then experimentally and theoretically generated while frictional torque versus angular velocity curves were also plotted. The results showed that the highest value of coefficient of friction as well as the frictional torque was obtained on the transversal micro-grooved journal bearings.