Feasibility study of a current mode gamma radiation dosimeter based on a commercial pin photodiode and a custom made auto-ranging electrometer

An experimental study has been conducted to evaluate the feasibility of a current mode gamma radiation dosimeter, consisting of a commercial PIN photodiode as a radiation sensor, and a custom made auto-ranging electrometer for real-time measurement of the PIN photodiode’s response under radiation exposure. The radiation induced direct current response for single PIN photodiodes with different active areas, as well as for multiple PIN photodiodes connected in parallel, has been investigated. Three types of commercial silicon PIN photodiodes have been chosen for evaluation - S1223, BPW34, and PS100-6-CER2 PIN. During the experiment, five samples have been tested - three samples made of single PIN photodiodes (one sample of each photodiode type) and two samples formed by connecting multiple photodiodes in parallel (two BPW34 photodiodes in parallel and four BPW34 photodiodes in parallel). The samples have been irradiated with a 60Co gamma ray source and the relations between the induced photocurrent and the dose rate, and between the accumulated charge and the absorbed dose, have been determined. For measuring the photodiodes response, a custom made auto-ranging electrometer controlled by a personal computer, and capable of measuring direct currents from 50 pA to 10 mA with relative error less than 2.5%, has been used. Obtained results have shown very good linearity between the dose rate and the induced photocurrent for dose rates ranging from 0.93 Gy/h to 67 Gy/h. Also, very good linearity has been observed between the accumulated charge and the absorbed dose for all tested samples, within the investigated range of absorbed doses from 472 mGy to 3.3 Gy. On the basis of the obtained results, a simple model has been derived, enabling the estimation of the photodiode’s current response as a function of the dose rate and the photodiode’s geometry (active area and depletion layer width). [Projekat Ministarstva nauke Republike Srbije, br. 43011

The Forces of Architectural Design

Greg Lynn’s theorization of the animate form and animate design in architecture referred to the consideration of structural changes in the creation of architectural form caused by the advent of computer-aided design. His concept of animate form represented a departure from the idea of the autonomy of form created in abstract, atemporal space. In contrast, Lynn recognizes in the new software the opportunity to subordinate the (virtual) architectural form to the dynamic principles of motion and force. Similar to Deleuze’s idea that “[f]orce is presence and not action,” Lynn defines force as virtual motion and identifies it in the logic of 3D software’s vector curvilinearity, which indexically signifies the continual change in the form’s geometry. However, the “virtual force,” representing a simple geometric law, is also an analogue of the material force that actualizes the form by translating it into a technical structure. This duality, which echoes Leibniz’s distinction between the primitive and derivative forces, allows the category of force to overcome the paradigm of realization of the (autonomous) form. In this presentation, this double character of force will be used to interpret the point of “/” as that in which one can encounter simultaneity and absolute parallelism of the ideal and real aspects of architectural design

Bašlar en vacances: subjekt nadracionalizma i njegova funkcionalna vrednost

This paper deals with the problem of the subject in Bachelard’s concept of surrationalism. Focusing on the epistemological character of surrational creativity, the issue of the subject is approached through the analysis of the relationship between subjectivity and objectivity in the surrational act. Comparing the character of novelty in surrealism and surrationalism, the paper introduces Bachelard’s distinction between formal and material imagination, with the latter further discussed through the prepositions “against” [contre] and “in” [dans]. Bachelard’s theory of the internal dialectic – the theory of subdivision of the subject – is analyzed through his concept of reverie. The last chapter deals with the dialectic between the apodictic and the assertoric subject, aiming to reconsider the idea of interiority and repose.Rad se bavi problemom subjekta unutar Bašlarovog koncepta nadracionalizma. Fokusirajući se na epistemološki karakter nadracionalne kreativnosti, pitanju subjekta se pristupa kroz analizu odnosa subjektivnosti i objektivnosti u činu nadracionalizma. Sa ciljem poređenja karaktera novog u nadrealizmu i nadracionalizmu, pristupljeno je analizi Bašlarove distinkcije između formalne i materijalne imaginacije, čiji se dijalektički karakter dalje razmatra kroz predloge „protiv“ [contre] i „u“ [dans]. Takođe, Bašlarova teorija unutrašnje dijalektike – teorija podele subjekta – analizira se kroz njegov koncept sanjarije. U poslednjem poglavlju se ovaj problem analizira unutar dijalektike između apodiktičkog i asertoričkog subjekta, sa namerom da se preispita ideja unutrašnjosti i počinka

Between the Primitive and Plastic: Deleuzian Ontology of Architectural Design

The discursive difference between the ideal and material architectural object could almost be completely reduced to the issue of translation of the former into the latter. Within such a perspective, it becomes difficult to think of architectural design beyond the order of precedence, which defines the Form’s ontological autonomy from its material expression. In my presentation, I will try to reinterpret this relationship using Deleuze’s theory of fold. Regarding Leibniz’s distinction between the primitive and (derivative) plastic forces, through which Deleuze interprets the difference between soul and matter as the difference between the one and many, the concept of fold offers the possibility of a “twofold” reading of design methodology. Such duality would refer to overcoming the paradigm of “materialization” of form, that is, the always one-way translation process, understood as the multiplication of the one. In other words, Leibnizian hylomorphism is reflected in the concept of the fold on the level of its position between the corresponding processes of unification and multiplication. Using the concept of harmony, which is the unity of the multiple, Deleuze defines this kind of correspondence as a necessary twofoldness, i.e. “the double operation of transcendental actualization and realization” – the former as intrinsic and the second as extrinsic folding. Nevertheless, their mutual order remains an order of precedence: the intrinsic folding is necessarily primitive, or primary since its only reference is the self. In the methodology of architectural design, however, this order becomes impossible with the question of form being posed with respect to the problem of morphogenesis. Between the actual and the real, the morphogenetic process itself then turns into an infinite correspondence, whereby the primitive quality of form would have to identify with its plasticity

Numerical simulation of multiphase flow around suction plates of ventilation mill in the function of extending its remaining working life

Ovaj rad prestavlja mogućnost korišćenja rezltata numeričkih simulacija, za smanjenje habanja radnih delova ventilacionog mlina za mlevenje uglja u termoelektrani Kostolac B. Mogućnost revitalizacije usisnih ploča ventilacionog mlina je zasnovan na 3D numeričkoj simulaciji multifaznog strujanja u ventilacionom mlinu. Čvrste čestice smeše ugalj, mineralne materije, pesak tokom procesa mlevenja izazivaju veliko habanje usisnih ploča. Primenom softverskog paketa ANSYS FLUENT 12, dobiće se detaljniji prikaz multifaznog strujanja i brzine mešavine koja omogućuje da se na osnovu intenziteta i smera brzine, preciznije odrede kritične zone u kojima će se pojaviti oštećenja kod usisnih ploča ventilacionog mlina. Korišćen je Euler-Euler model mešavine. Rezultati dobijeni pomoću numeričke simulacije koristiće se za izbor optimalne tehnologije revitalizacije usisnih ploča ventilacionog mlina. Primenom ovog pristupa rešavanja problema smanjio bi se broj mogućih interventnih popravki i produžio bi se period između neophodnih kompletnih remonta postrojenja, čime bi se ostvarili značajni ekonomski efekti i ujedno povećala energetska efikasnost termoenergetskih agregata.This paper presents results of the analyses obtained by numerical simulation for the possibilities of increasing the wear resistance of the ventilation mill working parts for coal grinding in the Kostolac B power plant. The possibilities for modification are based on 3D numerical simulation of multiphase flow of ventilation mill. Mineral materials during the process of milling in the ventilation mill cause strong wear of the suction plates. The multiphase flow simulations are performed in order to obtain the mineral materials paths and velocity vectors. The mixture model of the Euler-Euler approach is used. The results obtained in the numerical simulation serve for the selection of an optimal redesign of the suction plates. The application of this approach can reduce the number of possible repairs and extends the period between them, resulting in significant economic effects

Numerical simulation of multiphase flow around suction plates of ventilation mill in the function of extending its remaining working life

Ovaj rad prestavlja mogućnost korišćenja rezltata numeričkih simulacija, za smanjenje habanja radnih delova ventilacionog mlina za mlevenje uglja u termoelektrani Kostolac B. Mogućnost revitalizacije usisnih ploča ventilacionog mlina je zasnovan na 3D numeričkoj simulaciji multifaznog strujanja u ventilacionom mlinu. Čvrste čestice smeše ugalj, mineralne materije, pesak tokom procesa mlevenja izazivaju veliko habanje usisnih ploča. Primenom softverskog paketa ANSYS FLUENT 12, dobiće se detaljniji prikaz multifaznog strujanja i brzine mešavine koja omogućuje da se na osnovu intenziteta i smera brzine, preciznije odrede kritične zone u kojima će se pojaviti oštećenja kod usisnih ploča ventilacionog mlina. Korišćen je Euler-Euler model mešavine. Rezultati dobijeni pomoću numeričke simulacije koristiće se za izbor optimalne tehnologije revitalizacije usisnih ploča ventilacionog mlina. Primenom ovog pristupa rešavanja problema smanjio bi se broj mogućih interventnih popravki i produžio bi se period između neophodnih kompletnih remonta postrojenja, čime bi se ostvarili značajni ekonomski efekti i ujedno povećala energetska efikasnost termoenergetskih agregata.This paper presents results of the analyses obtained by numerical simulation for the possibilities of increasing the wear resistance of the ventilation mill working parts for coal grinding in the Kostolac B power plant. The possibilities for modification are based on 3D numerical simulation of multiphase flow of ventilation mill. Mineral materials during the process of milling in the ventilation mill cause strong wear of the suction plates. The multiphase flow simulations are performed in order to obtain the mineral materials paths and velocity vectors. The mixture model of the Euler-Euler approach is used. The results obtained in the numerical simulation serve for the selection of an optimal redesign of the suction plates. The application of this approach can reduce the number of possible repairs and extends the period between them, resulting in significant economic effects

Methodology of incereasing reamening working life parts of ventilation mills

Последњих година спроводе се значајна истраживања, која се односе на продужење животног века радних делова термоенергетских постројења. Опрема у термоелектранама је изложена дуготрајном дејству високих температура и притисака, хабању и цикличном оптерећењу. У наведеним условима експлоатације различити узроци могу довести до оштећења, појединих компонената као што је хабање радних делова вентилационог млина. Последице су смањење производног капацитета и вентилационог дејства млина у односу на пројектовану вредност, као и чести застоји због замене делова, што значајно утиче на продуктивност, економичност и енергетску ефикасност термоелектране. Уколико се констатује оштећење компоненте, које може довести до поремећаја у раду постројења, у пракси постоје три могућности: да се она остави у погону уз редовну и чешћу контролу, да се изврши ревитализација компоненте или да се замени потпуно новом компонентом. Одлука се доноси на основу техничких, технолошких и економских критеријума у зависности од могућности набавке новог дела, цене замене или ревитализације, могућности заустављања постројења и аспеката сигурности и заштите околине. У овиру ове докторске тезе пажња је усмерена на анализу радних услова и израду процедуре за продужење радног века делова вентилационог млина у Термоелектрани Костолац Б, поступцима наваривања и метализације. Тачније, предмет ових истраживања ће бити да се на основу техничко – технолошке анализе рада и стања компоненти вентилационог млина, које су доминантно изложене абразивном и ерозивном хабању, изврши избор радног дела, у овом случају усисних плоча, као и карактеризација основног материјала. Први део дисертације је усмерен и на примену савремених метода нумеричке симулације вишефазног струјања у вентилационом млину у циљу детаљније анализе услова хабања (проблема) везаних за појаву абразије и ерозије изабране компоненте. На овај начин, применом софтверског пакета ANSYSFLUENT 12, добиће се детаљнији приказ мултифазног струјања и брзине мешавине која омогућује да се на основу интензитета и смера брзине, прецизније одреде критичне зоне у којима ће се појавити оштећења елемената вентилационог млина. Ове зоне се по правилу налазе у оним деловима млина, у којима је због смера и брзине струјања као и удела чврстих честица смеше (угаљ, минералне материје, песак) највеће хабање истих...In recent years implemented significant research, concerning the extension of the life of the working parts of a thermal energy plant. Equipment in thermal power plants exposed to long-term effect of high temperatures and pressure, abrasion and load cycle counting. In these circumstances the exploitation of different causes can lead to damages, the individual components such as the wear and tear of working parts of an air mill. The consequences of the reduction in production capacity and air operations of the mill compared to the projected value, as well as frequent delays due to the replacement of parts, which significantly affects the productivity, profitability and energy efficiency of thermal power plants. If is detected damage to components, which can lead to disturbances in the plant, in practice there are three possibilities: that it be left in the drive with a regular and frequent control, to carry out a revitalization component or to replace entirely new component. The decision is made on the basis of technical, technological and economic criteria, depending on the possibilities for acquiring new works, replacement rates or revitalization, the possibilities of stopping the plant and aspects of safety and environmental protection. As part of this doctoral thes is in focus on the analysis of working conditions and create procedures for the extension of the service life of parts of the ventilation mill in thermal power plant Kostolac B, surfacing and metallization processes. More specifically, the subject of this research will be that based on the technical - technological analysis of the work and the state of the components of the ventilation mills, which are predominantly exposed to abrasive and erosive wear, make the selection of the working part, in this case the suction plate and the characterization of the base material. The first part of the dissertation will focus on the use of modern methods of numerical simulation of multiphase flow in ventilation mill for the purpose of detailed analysis of problems related to the occurrence of abrasion and erosion of the selected component. In this way, using the software package ANSYS FLUENT 12, will get a more detailed view of multiphase flow and speed of the mixture that enables that based on the intensity and direction of speed, precisely identify critical areas in which will appear the breakdown of the ventilation mill. These zones are typically located in those parts of the mill, which is due to the direction of flow velocity and content of solid particles mixtures (coal, minerals, sand) maximum wear them...