Experimental investigation on water injected twin screw compressor for fuel cell humidification

A water injection in Twin Screw compressors was examined in order to develop effective humidification and cooling schemes for fuel cell stacks as well as cooling for compressors. The temperature and the relative humidity of the air at suction and exhaust of the compressor were monitored under constant pressure and water injection rate and at variable compressor’s operating speeds. The experimental results showed that the relative humidity of the outlet air was increased by the water injection. The injection tends to have more effect on humidity at low operating speeds/ mass flow rates. Further humidification can be achieved at higher speeds as higher evaporation rate becomes available. It was also found that the rate of power produced by the fuel cell stack was higher than the rate used to run the compressor for the same amount of air supplied. The efficiency of the Balance-Of-Plant (BOP) was therefore higher when more air is delivered to the stack. However, this increase in the air supply needs additional subsystems for further humidification/ cooling of the BOP system

Aperiodic tilings and entropy

In this paper we present a construction of Kari-Culik aperiodic tile set - the smallest known until now. With the help of this construction, we prove that this tileset has positive entropy. We also explain why this result was not expected

Employer branding in european online job days virtual recruitment events:a case study

Abstract. As Finland suffers from a lack of work force, new ways to conduct international recruitment are implemented. The Finnish government’s plan includes drastically increasing the amount international talent recruited to Finnish companies. Companies themselves also increasingly conduct international recruitment. There are projects and services available to help the process. One such service is EURES. EURES organizes online recruitment events called European Online Job Days to help companies access the European labor market as well as enable the free movement of European workers. As more and more companies start attracting foreign talent, the competition for the attention of these professionals increases. Through employer branding companies can differentiate and create attractive opportunities. The thesis introduces employer branding based on previous research and theories and applies that to investigate how Finnish companies attending the European Online Job Days events conduct employer branding and how effectively they are able to utilize the platform. Some important topics recognized were online brand communities that are formed, for example, on social media platforms. The recruitment event platform could be considered a social media platform as it includes a social aspect. Another important topic is eWOM or electronic word of mouth. Organizational culture and employee ambassadors were found to be effective in employer branding and some companies observed utilized these theories in their recruitment efforts. The thesis examines four Finnish companies attending three different online events. Another type of event attendance introduced is an info point which is a local municipality or regional development organization, with the purpose of attracting jobseekers. The thesis discovered four different engagement levels of attendance. This was based on the many of the available tools the companies used during the event day and assessing how invested the company was. There could be seen a lack of understanding how to efficiently maximize the effectiveness of the tools and how to utilize the platform effectively to conduct international recruitment. As international recruitment will become increasingly important, hiring managers, HR professionals and CEOs should utilize all available tools to maximize the reach of their recruitment efforts. Tools such as the European Online Job Days are good at reaching thousands of jobseekers and a clear trend towards increasing interest from the jobseekers’ side shows that the now is the time start using the platform. The events are free and thus they are a low-bar first step in international recruitment

SWAT-based runoff modeling in complex catchment areas: Theoretical background and numerical procedures

This paper shows the structure of the SWAT-based model used in modeling of the 'rainfallrunoff' process. The SWAT model is hydro-dynamic and physically-based model for application in complex and large basins. Model inputs are as follows: rainfall, air temperature, soil characteristics, topography, vegetation, hydrogeology and other relevant physical parameters. The model is based on five linear reservoirs as follows: reservoir of the vegetation cover, snow accumulation and melting, surface reservoir, underground reservoir and surface runoff reservoir. The model uses GIS tools for preprocessing and post-processing. The basic modeling unit is the hydrologic response unit (HRU), defined as the network of elementary hydrologic areas with the selected discretization, measure of which is dependent upon the desired accuracy, as well as upon data accuracy. The total runoff on the exit profile of the catchment is computed by convolution of the sum of runoffs (surface and base runoffs). The model can be applied at the daily and hourly level of discretization and used for multiannual simulations. Illustration of operation of the SWAT based model will be presented on a selected part of the River Drina basin (with the total area of around 20.000 km2).

Synthesis of LiCrxMn2-xO4 (x~0.18) by glycine-nitrate method

LiCr0.18Mn1.82O4 spinel has been successfully synthesized by glycine-nitrate method. As a cathode material for lithium batteries it shows initial discharge capacity of 107.1 mAh/g and capacity retention of 93.3% after ten cycles.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Aplikasi Sistem Vertical Dan Horizontal Sub Surface Flow Wetland Dalam Pengolahan Kembali Effluent Ipal Perusahaan Obat Dan Obat Tradisional

Penelitian ini mengolah effluent IPAL Perusahaan obat dan obat tradisional yang telah memenuhi baku mutu untuk di buang ke badan perairan. Pengolahan dilakukan untuk meningkatkan kualitas effluent IPAL agar dapat memenuhi klasifikasi air kelas III pada PP No 82 Tahun 2001. Pengolahan kembali effluent IPAL ini dilakukan dengan menggunakan metode yang berbeda yakni metode lahan basah buatan (wetland) karena pengolahan sebelumnya telah menggunakan IPAL dengan metode pengolahan secara fisika dan kimia. Tujuan dari penelitian adalah untuk mengkaji peningkatan kualitas effluent IPAL Perusahaan obat yang telah diolah dengan menggunakan metode lahan basah buatan aliran bawah permukaan vertikal (VSSF Wetland) dan lahan basah buatan aliran bawah permukaan horizontal (HSSF Wetland) serta mengkaji efisiensinya.Parameter-parameter air limbah yang digunakan adalah BOD, COD, nitrit dan amonia yang masih melebihi baku mutu air kelas III. Penelitian dilakukan secara eksperimental dengan skala lab yang dilakukan menggunakan dua buah reaktor yang berukuran sama. Reaktor diisi dengan media tanam berupa pasir dan kerikil, serta menggunakan tanaman mendong (Frimbistylis globulosa). Pengambilan sampel dilakukan selama empat belas hari dimana pengujian kualitas sampel tersebut dilakukan sebanyak tujuh kaliHasil penelitian menunjukkan bahwa kualitas effluent setelah diolah menggunakan VSSF maupun HSSF Wetland lebih baik daripada sebelum dilakukan pengolahan menggunakan kedua metode tersebut. VSSF Wetland secara efektif dapat menurunkan BOD, COD, nitrit dan amonia dengan efisiensi berturut-turut sebesar 89.38%, 91.78%, 54.84% dan 71.58%; sedangkan efisiensi HSSF Wetland berturut-turut 93.56%, 94.64%, 74.19% dan 59.93%. Hasil uji statistik menunjukkan tidak terdapat perbedaan kualitas effluent yang diolah menggunakan sistem VSSF dan HSSF Wetland untuk variabel nitrit, amonia, COD dan BOD

Generation and transport of fast hydrogen atoms in glow discharges

Ова докторска дисертација има за тему истраживање настанка и транспорта брзих атома водоника у тињавим пражњењима. Појава брзих атома у пражњењима је први пут примећена пре нешто више од две деценије и до данас је предмет експерименталних и теоријских истраживања у више лабораторија широм света. Аномално проширени профили спектралних линија водоника су указали на присуство атома изузетно високих енергија. Преовлађујући ''колизиони модел'' објашњава ову појаву убрзавањем водоникових јона у електричном пољу пражњења и конверзијом јона у атоме у процесима измене наелектрисања и у сударима са површином катоде. Осим колизионог модела данас постоје и конкурентске теорије. Циљ овог рада је била верификација колизионог модела и испитивање његове примене на тињава пражњења. У тези су коришћене експерименталне методе оптичке емисионе спектроскопије као и декомпозиција измерених профила Балмер алфа линије праћена математичком анализом. Испитивани су извори нискотемпературне плазме на сниженим притисцима. Коришћена су четири типа тињавих пражњења са једносмерном, импулсном и наизменичном струјом, са водоником и мешавином водоника и аргона као радним гасом. Зрачење је испитивано у два правца посматрања. Испитиван је утицај параметара једносмерних пражњења на брзе атоме водоника. Резултати су показали да независне промене притиска и напона утичу на популацију брзих атома различито. Спроведен је експеримент за испитивање утицаја катоде са малом атомском рефлексијом на аномално проширене профиле и одговарајуће особине популације брзих атома у абнормалном тињавом пражњењу. При посебним условима у пражњењу са нискорефлективном катодом је забележена трансформација облика профила линије. Спектроскопска испитивања су вршена у имплусном тињавом пражњењу као и у диелектричном баријерном пражњењу. У раду су описани детаљи развијене Монте Карло симулације за протоне и брзе атоме у тињавом пражњењу и дати резултати поређења са експериментом. Резултати и анализе приказани у овом раду се могу сматрати верификацијом колизионог модела за брзе атоме у тињавим пражњењима. Развијене технике за испитивање расподела и особина брзих атома на основу емисионог профила линије се могу користити у различитим врстама плазми...The subject of this dissertation is the investigation of generation and transport of fast hydrogen atoms in glow discharges. The phenomenon of fast atoms in glow discharges was first observed over two decades ago and is still a subject of experimental and theoretical investigations in several laboratories worldwide. The excessive Doppler broadened profiles of hydrogen spectral lines have indicated the presence of atoms with exceptionally high energies. The commonly excepted ''collision model'' explains this phenomenon through acceleration of hydrogen ions in the electric filed of the discharge, and conversions of ions into atoms in the charge exchange processes and in the collisions with cathode surface. Apart from the collision model, competitive theories exist today. The aim of this work was to verify the collision model and investigate of its application to glow discharges. Experimental methods of optic emission spectroscopy were used in the dissertation; as well as decomposition of measured Balmer alpha line profiles followed by mathematical analysis. Sources of low temperature plasma at low pressures were investigated. Four types of glow discharges were used, with direct current, pulse and alternative current; in hydrogen and argon-hydrogen mixture. Radiation was examined in two directions of observation. The influence of discharge parameters of direct current discharges on the fast atoms was investigated. Results have shown that independent variations of pressure and voltage affect the species of fast atoms differently. An experiment was undertaken to examine the influence of cathode with reduced atomic reflection on excessively broadened line profiles and corresponding characteristics of fast atoms species in the abnormal glow discharge. In the specific discharge conditions, transformation of line profile shape was detected with use of low reflective cathode. Spectroscopic investigations were performed in a pulse glow discharge and in the dielectric barrier discharge. In the work the details of developed Monte Carlo simulation for protons and fast atoms are presented and results of comparison with experiment are given. Results and analysis presented in this work may be regarded as verification of collision model for fast atoms in glow discharges. The techniques developed here for examination of distributions and characteristics of fast atoms based on emission line profile may be used in different types of plasma..

Tadija Smičiklas and the Greek Catholic Seminary

Autor u radu razmatra neke od najvažnijih razdoblja u životu Tadije Smičiklasa. Osvrće se na razdoblje njegova učiteljevanja u Osijeku, studiranje u Pragu i Beču, profesuru na gimnaziji u Rijeci, te razdoblje kada je bio ravnatelj Grkokatoličkog sjemeništa u Zagrebu.The author in this work analyses the most important periods in Tadija Smičiklas’s life, using to a great extent currently still unknown sources from the Archive of the diocese of Križevci: the correspondence between T. Smičiklas and his uncle, Bishop Đuro Smičiklas of Križevci. After a brief survey of the history of the Smičiklas family, the author reflects on the first period of Smičiklas’s education, when he was a pupil at the Greek Catholic Seminary in Zagreb. At that time, Smičiklas was an active member of the Ilirsko društvo [Illyrian society] and the “reading room,” and he also participated as an author in the weekly Vienac [The garland]. After finishing his secondary education, Smičiklas left the Seminary and went to Osijek, where he worked as a teacher of Croatian language and history. Longing for higher education, he went to study history in Prague. During his stay there he made a great contribution to the Croatian scholarship by discovering the correspondence of the Zrinski family and other manuscripts important for Croatian history. During the period from 1865 to 1869, Smičiklas continued his study in Vienna at the Institut für die österreichische Geschichtsforschungen, and during that period he was financially supported by his uncle, Bishop Đuro. After finishing his studies in Vienna, Smičiklas was appointed lecturer at the gymnasium in Rijeka. He considered this a provincial town and the appointment as a setback. His wish to work in Zagreb was fulfilled in 1873, when he was elected director of the Greek Catholic Seminary. In 1887 he was elected professor of historical auxiliary sciences on the Faculty of Arts in Zagreb. In conclusion, the author emphasises the point that there were two factors which influenced to a great extent Smičiklas’s educational and scientific biography: his time at the Greek Catholic Seminary in Zagreb, and the supportive role of his uncle, Bishop Đuro Smičiklas of Križevci