Development and evaluation of transfer functions for a variable speed compressor

In this study, transfer functions of electronic expansion valve and variable speed scroll compressor in a chiller system are developed based on an experimental analysis. Dynamic behaviours of water temperature at chiller output and refrigerant superheat at evaporator outlet have either the first- or the second-order linear models, respectively. Different from the existing modelling studies in literature novel models are presented for variable speed refrigeration system with scroll compressor and liquid type evaporator. The scroll compressor used in the current study is not produced for variable speed operation however it is operated with some limitations in the range of 30 to 50 Hz through an inverter. Similar restrictions are presented for the electronic expansion valve as 10 per cent to 35 per cent opening range because of operational limitations. To validate transfer functions of the variable speed scroll compressor and electronic expansion valve, mean square error values for all transfer functions are calculated. The mean square error values vary between 0.0126 and 0.3116. In addition, all transfer functions are designed and tested using corresponding proportional-integral-derivative controllers in order to see their applicability. The results indicate that energy savings are a consequence of operating the chiller at smaller frequencies than the basic 50 Hz while partial load occurred. © Authors 2011

A microcontroller based test platform for controller design

The Institute of Electrical and Electronics Engineers (IEEE);IEEE Industrial Electronics Society (IES);IEEE Control Systems Society (CSS);Society of Instrument and Control Engineers (SICE-Japan);Politecnico di Bari2010 IEEE International Symposium on Industrial Electronics, ISIE 2010 -- 4 July 2010 through 7 July 2010 -- Bari -- 83019This paper presents a microcontroller based emulator which is developed for the design-test-and-redesign of controllers through examining the controller candidates on the emulated plants operating under the created real-time and real environmental conditions. The analog and digital peripheral units of the plant emulator provide the recreation of the real environmental conditions such that the whole emulator runs as if the real plant whenever the model implemented in the microcontroller is a right model for the plant. The emulator has the flexibility of changing the plant model and/or its parameters manually and it also enables to apply, in an automatic way, analog disturbances and analog parameter perturbations to the plant model. The developed plant emulator communicated with the simulator of the controller part both managed by a graphical user interface implemented in the computer constitutes a controller design-test-redesign platform which has the advantages of using simulated plants in the controller design providing a test-flexibility and also of testing the controller candidates on the emulated plants operating under the conditions very close to the real situations, so assuring the desired controller performances. © 2010 IEEE

Petrogenesis of basalts from southern Turkey: The Plio-Quaternary volcanism to the north of Iskenderun Gulf

The Quaternary volcanicity north of the Iskenderun Gulf in the eastern Mediterranean is represented by small basaltic scoria cones and flows. Approximately 115 km2 of land area is occupied by young basalts which straddle both the main (the Karatas-Osmaniye Fault Zone) strike-slip fault system which forms the Africa-Turkey Plate boundary and the suture of the southern arm of the former Neotethys Ocean. Detailed petrological and geochemical analyses of these rocks have been carried out, with the aim of trying to understand why they have erupted in this locality. The rocks consist mainly of basanites (43-46% silica; 3.9-6.5% alkalis) and some alkali olivine basalts (45% silica; 3.8-4.2% alkalis). Both the basanites and alkali olivine basalts are porphyritic, vitrophyric and highly vesiculated with euhedral and subhedral olivine (Fo82-Fo78) phenocrysts set in a fine-grained groundmass of olivine (Fo70), plagioclase (An71-An66), clinopyroxene and titanomagnetite. Olivine phenocrysts contain abundant Cr-spinel and titanomagnetite inclusions. Some geochemical characteristics of these basalts indicate similarity with extension-related alkali basalts; others indicate similarity with ocean island basalt; and yet others indicate subduction-related characteristics. This complexity leads to difficulties with interpretation, especially since there is no demonstrable local extension, subduction or mantle plume activity in the vicinity

Congenital central alveolar hypoventilation syndrome (Ondine's curse) associated with Hirschsprung's disease: A case report Doǧumsal santral alveoler hipoventilasyon sendromuna eşlik eden Hirschsprung hastaliǧi: Olgu sunumu

Congenital central alveolar hypoventilation syndrome named as "Ondine's curse" is commonly associated with other neurocrestopathies. Our case that is associated with Hirschsprung's disease, is presented to review the diagnostic modalities and stress the difficulties in treatment in our country

Evaluation of skeletal changes associated with surgically rapid palatal expansion without pterygomaxillary separation

Introduction: To evaluate skeletal and nasal volume changes before and after surgery in surgically assisted rapid palatal expansion (SARPE) without pterygomaxillary separation and compare the dental changes by digital model analysis and radiographic analysis