A universal amperometric membrane-covered gas-sensing electrodes system: Measurement of dissolved oxygen, ozone and chlorine dioxide.

A Universal Amperometric Membrane-Covered Gas-Sensing Electrode System has been designed which can be used with a wide variety of electrochemical sensors. The system is composed of two parts: an electrode detection unit consists of an Intel 8051 microprocessor as the control unit which receives operational commands through the serial port of a personal computer. The assembly language has been written and is embedded in a 32K EPROM and the data collected are temporarily stored in a 32K RAM. A potentiostat with an auto-adjustable 100 nA to 100 {dollar}\\mu{dollar}A range is used to polarize the electrode. A 12 bit D/A convertor with 1 mV resolution can accurately control the potential between {dollar}-{dollar}2 V and +2 V, and a high resolution 12 bit A/D convertor is used to digitize the electrode signal. The system has been programmed for seven electrochemical techniques which can be applied to any amperometric sensor. The collected binary code is transferred to the PC via an RS-232 serial port. Software programmed with C language is operated on a Windows 95 platform and has a GUI front-end to allow the operator to select one of the seven methods as well as modify the appropriate parameters to conduct the experiment. The selected parameters are transferred to the electrode detection unit to automatically control the measurement. The collected data are shown graphically and numerically on the screen and can be saved, retrieved or printed. This Universal Sensor System has been used to measure low levels of oxygen, ozone and chlorine dioxide in water. Double potential step chronocoulometry has been used to eliminate the stirring effect commonly encountered with steady state amperometric membrane electrodes. Calibration curves are linear and detection limits of 30 {dollar}\\mu{dollar}g/L and 50 {dollar}\\mu{dollar}g/L were achieved for chlorine dioxide and ozone, respectively

Meja kot razlika, metafora in diskurz

Meje nacionalnih držav, pravita avtorici, so utelešenje stika med sistemom in življenjskim svetom, so učbeniško nazorna podoba tega, kako se družbeni prostori prevajajo v fizične in narobe. V članku razmišljata, kako se meje v prostoru vzpostavljajo, ohranjajo in tudi brišejo na podlagi razlik in opozicij (mi in oni, tukaj in tam, varnost in nevarnost, vključeni in izključeni ...). V primeru meja med nacionalnimi državami se razlike prepoznavajo in utemeljujejo izključno v sferi politike, natanko iste politike, ki potrebuje meje in razlike, da bi se sploh lahko konstituirala. Osrednji del besedila je kvalitativna raziskava vsakdanjega doživljanja in pomenov meje med Italijo in nekdanjo Jugoslavijo ter Slovenijo v treh obdobjih: ob vzpostavljanju meje v letih 1953/54, nato v desetletjih, ki so sledila vse do vstopa Slovenije v Evropsko unijo, in v obdobju "izginjanja meje" po letu 2004. Avtorici mislita, da je izkušnjam življenja ob meji skupno sporočilo, kako zelo je polje "absolutne politike" obvladovalo vsakdanja življenja ljudi in v prelomnih obdobjih tudi terjalo radikalne odločitve in identitetne preobrazbe.The borders of nation-states, the authors claim, are an embodiment of the junction between the system and life-world. They manifest the translation of the social into physical spaces and vice versa. The authors reflect the meaning of distinctions and oppositions (us and them, here and there, safety and danger, included and excluded etc.) in the construction, maintenance and disappearance of boundaries in space. When it comes to the borders of nation-states distinctions are identified within and grounded solely in the political sphere, the same sphere that needs borders and distinctions in order to constitute itself. A qualitative study about the experience and meaning of the Yugoslav-Slovenian-Italian border lies at the core of the article. Three historical periods are highlighted: the constitution of the border in 1953/54, followed by several decades leading up to Slovenia joining the European Union and the "border disappearance" period after 2004. The authors believe that the field of "absolute politics" dominated over the everyday experiences of the people living in the border area and, when some turning points occurred, demanded radical decisions and identity transformations

Living on the Border. Three Generations\u27 Biographies.

Borders of nation states, claim the authors, are embodiment of junction between system and lifeworld. They manifest the translation of social into physical spaces and vice versa. The authors reflect the meaning of distinctions and oppositions (us and them, here and there, safety and danger, included and excluded etc.) in construction, maintenance and disappearance of boundaries in space. In case of borders of nation states the distinctions are identified within and grounded solely upon the political sphere, the same sphere that needs borders and distinctions in order to constitute itself. A qualitative study about the experience and meaning of Yugoslav-Slovenian-Italian border is at the core of the article. Three historical periods are highlighted: the constitution of the border in the years 1953/54, followed by decades up to the entrance of Slovenia in European Union in 2004 and the period of “vanishing and reappearing border” after 2004. The authors believe that the field of “absolute politics” dominated over everyday experiences of people living in the border area and – when some turning points occurred – demanded radical decisions and identity transformations

Issue brief: Arab Americans and language policy

This brief describes the contemporary state of language policy in the US focusing on Arab Americans role in American language policy. Also it serves to show education rates and levels of discrimination on Arab Americans

Living on the Border: Three Generations\u27 Biographies

Borders of nation states are the embodiment of junction between system and lifeworld. They manifest the translation of social into physical spaces and vice versa. The authors reflect the meaning of distinctions and oppositions (us and them, here and there, safety and danger, included and excluded etc.) in construction, maintenance and disappearance of boundaries in space. In the case of borders of nation states the distinctions are identified within and grounded solely upon the political sphere, the same sphere that needs borders and distinctions in order to constitute itself. A qualitative study about the experience and meaning of Yugoslav-Slovenian-Italian border is at the core of the article. Three historical periods are highlighted: the constitution of the border in the years 1953/54, followed by decades up to the entrance of Slovenia in European Union in 2004 and the period of “vanishing and reappearing border” after 2004. The authors believe that the field of “absolute politics” dominated over every day experiences of people living in the border area and – when some turning points occurred – demanded radical decisions and identity transformations

Parallel batching with multi-size jobs and incompatible job families

Parallel batch scheduling has many applications in the industrial sector, like in material and chemical treatments, mold manufacturing and so on. The number of jobs that can be processed on a machine mostly depends on the shape and size of the jobs and of the machine. This work investigates the problem of batching jobs with multiple sizes and multiple incompatible families. A flow formulation of the problem is exploited to solve it through two column generation-based heuristics. First, the column generation finds the optimal solution of the continuous relaxation, then two heuristics are proposed to move from the continuous to the integer solution of the problem: one is based on the price-and-branch heuristic, the other on a variable rounding procedure. Experiments with several combinations of parameters are provided to show the impact of the number of sizes and families on computation times and quality of solutions