1,720,998 research outputs found
Influence of ventilation on the microclimate parameters of the mine of St. Barbara : master's thesis
No full textU ovom diplomskom radu analizirat će se podatci prikupljeni mrežom senzora koji su postavljeni unutar rudnika koristeći programski jezik Python. Na temelju podataka prikazani su dijagrami i histogrami koji će pokazati uspješnost rada novog ventilatora koji je ugrađen radi smanjivanje vlage unutar rudnika. Analizom podataka koji su učitani u Python i potom uz korištenje programskog koda i algoritama dobiveni su rezultati kretanja rosišta, temperature i relativne vlage kroz vrijeme. Dobivena su ukupna vremena kad je ventilator radio tlačno, depresijski i kad je bio ugašen. Pokazano je da je ventilator opravdan u rudniku jer postoji nepovoljno vrijeme gdje bi moglo doći do kondenzacije vlage ako se ne upali ventilator. Koristeći unutranje senzore pokazalo se da nikad nije došlo do kondenzacije vlage unutar rudnika. Prikazana su kretanja apsolutne vlage kad ventilator radi i kad je ugašen. Analizom je prikazano da apsolutna vlaga pada dok ventilator radi, a raste kad je ugašen. Također u različitim periodima godine postoje i slučajevi gdje apsolutna vlažnost pada na senzorima bliže ulazu zračne struje a poraste na senzorima bliže izlazu zračne struje.This thesis will analyze data collected by a network of sensors placed inside the mine using the Python programming language. Based on the data, diagrams and histograms are presented that will show the success of the new fan installed to reduce moisture inside the mine. By analyzing the data that was loaded into python and then with the use of program code and algorithms, the results of the movement of the dew point, temperature and relative humidity over time were obtained. The total times when the ventilator was working in push mode, in pull mode and when it was turned off were obtained. It has been shown that the fan is justified in the mine because there is unfavorable weather where moisture condensation could occur if the fan is not turned on. Using internal sensors, it was shown that moisture condensation never occurred inside the mine. The movements of absolute humidity are shown when the fan is running and when it is turned off. The analysis showed that the absolute humidity falls while the fan is running, and rises when it is turned off. Also, in different periods of the year, there are cases where the absolute humidity drops on the sensors closer to the entrance of the air stream and rises on the sensors closer to the exit of the air stream
The influence of rock material properties on excavator productivity and optimal operating parameters : doctoral dissertation
No full textHidraulički bager jedan je od najčešće korištenih strojeva u rudarstvu te zbog toga postoji veliki interes istraživača za proučavanjem njegovoga učinka i optimizacije rada. Istraživanje u okviru ovog rada zasniva se na detaljnom proučavanju rada bagera u realnim uvjetima. Takva su istraživanja, prema dostupnoj literaturi, relativno skromna te postoji veliki prostor za napredak. Kako bi se pristupilo podatcima koji pružaju uvid u realni rad bagera potrebno je kontinuirano mjerenje produljenja i tlakova na hidrauličkim cilindrima. To je ostvareno pomoću specifičnoga mjernog sustava kojim se izvodi simultano mjerenje većeg broja parametara na bageru pri radu u realnim uvjetima. Izmjereni podatci obrađeni su pomoću računalnoga programa napisanoga u programskom jeziku Python. Pomoću standardnih kinematičkih i dinamičkih modela bagera dobivene su vrijednosti dinamičkih veličina rada (sila, snaga i utrošak energije pri kopanju) te geometrijskih veličina kopanja (kut upada zuba, duljina i površina reza). Terenska mjerenja izvedena su na pet različitih modela bagera te ukupno trinaest materijala. Laboratorijskim i terenskim ispitivanjima utvrđene su značajke materijala (granulacija, sadržaj vlage i nasipna gustoća). U radu je proračunat učinak kopanja koji predstavlja masu ili volumen iskopanog materijala u vremenu koje je bilo potrebno za izvođenje kopanja. U okviru statističke obrade podataka izvedene su višestruke regresijske analize utjecaja značajki materijala na dinamičke veličine rada bagera i geometriju kopanja. Regresijskom analizom također je prikazan utjecaj karakteristika materijala i geometrije kopanja na učinak. Utvrđeno je da granulometrijski sastav rastresitih materijala predstavlja najutjecajnije svojstvo na učinak kopanja, dok je duljina trajektorije kopanja najutjecajnija geometrijska veličina. Detaljnom analizom zasebnih ciklusa rada bagera utvrđena je razlika optimalne trajektorije kopanja u različitim materijalima. Predložena je klasifikacija učinka kopanja bagera u različitim materijalima. Također je predložen model za procjenu značajki materijala na temelju dinamičkih veličina rada bagera.The hydraulic excavator is one of the most commonly used machines in mining. Because of this, researchers have a great interest in studying its productivity and optimization of work. The research within this work is based on a detailed study of the operation of an excavator in real conditions. According to the available literature, such research is relatively modest and there is a lot of room for improvement. In order to access the data that provides insight into the real operation of the excavator, it is necessary to continuously measure the extension and pressures on the hydraulic cylinders. This is achieved by using a specific measuring system that can perform a simultaneous measurement of several parameters on the excavator during its work in real conditions. The measured data was processed using a computer program written in the Python programming language. Using standard kinematic and dynamic models of excavators, values of dynamic parameters of work (force, power, and energy consumption during digging) and geometric parameters of digging (tooth angle, length, and cutting area) were obtained. The field measurements were performed on 5 different machines and a total of 13 materials. Laboratory and field measurements determined the characteristics of the material (granulation, moisture content, and bulk density). In the paper, the productivity of digging was calculated, which represents the mass or volume of the excavated material in the time it took to perform the digging. In the frame of the statistical processing of data, multiple regression analyses have been performed on the influence of the characteristics of the material on the dynamic parameters of the excavator and the digging geometry. By regression analysis, the influence of the characteristics of the rocks and the geometry of digging on the productivity of digging are also shown. The size distribution has been found to be the most influential property of non-cohesive materials on the productivity of digging, while the length of the digging trajectory is the most influential geometric size. Through detailed analysis of the separate work cycles of the excavators, the difference in optimal digging trajectory in different materials has been determined. The classification of productivity of excavators digging in different materials is proposed. A model for assessing the characteristics of the materials based on the dynamic working parameters of the excavator is also proposed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Analiza točke rosišta atmosferskog zraka u okolini Rudnika sv. Barbara u Rudama : završni rad
No full textRad se bavi teorijskom obradom atmosferskog zraka i njegove vlage te zatim proračunom temperature rosišta kroz 10 godina i njegovo prikazivanje dijagramima i histogramima, sve rađeno u svrhu smanjenja vlažnosti unutar samog rudnika sv. Barbare u Rudama..Cilj ovog rada je utvrditi vrijeme kada je točka rosišta ispod temperature stijene u rudniku, čime se osigurava da neće doći do kondenzacije vlage , a zrak ima određeni kapacitet da primi dio vlage sa podgrede i stijenki rudnika
The influence of rock material properties on excavator productivity and optimal operating parameters : doctoral dissertation
No full textHidraulički bager jedan je od najčešće korištenih strojeva u rudarstvu te zbog toga postoji veliki interes istraživača za proučavanjem njegovoga učinka i optimizacije rada. Istraživanje u okviru ovog rada zasniva se na detaljnom proučavanju rada bagera u realnim uvjetima. Takva su istraživanja, prema dostupnoj literaturi, relativno skromna te postoji veliki prostor za napredak. Kako bi se pristupilo podatcima koji pružaju uvid u realni rad bagera potrebno je kontinuirano mjerenje produljenja i tlakova na hidrauličkim cilindrima. To je ostvareno pomoću specifičnoga mjernog sustava kojim se izvodi simultano mjerenje većeg broja parametara na bageru pri radu u realnim uvjetima. Izmjereni podatci obrađeni su pomoću računalnoga programa napisanoga u programskom jeziku Python. Pomoću standardnih kinematičkih i dinamičkih modela bagera dobivene su vrijednosti dinamičkih veličina rada (sila, snaga i utrošak energije pri kopanju) te geometrijskih veličina kopanja (kut upada zuba, duljina i površina reza). Terenska mjerenja izvedena su na pet različitih modela bagera te ukupno trinaest materijala. Laboratorijskim i terenskim ispitivanjima utvrđene su značajke materijala (granulacija, sadržaj vlage i nasipna gustoća). U radu je proračunat učinak kopanja koji predstavlja masu ili volumen iskopanog materijala u vremenu koje je bilo potrebno za izvođenje kopanja. U okviru statističke obrade podataka izvedene su višestruke regresijske analize utjecaja značajki materijala na dinamičke veličine rada bagera i geometriju kopanja. Regresijskom analizom također je prikazan utjecaj karakteristika materijala i geometrije kopanja na učinak. Utvrđeno je da granulometrijski sastav rastresitih materijala predstavlja najutjecajnije svojstvo na učinak kopanja, dok je duljina trajektorije kopanja najutjecajnija geometrijska veličina. Detaljnom analizom zasebnih ciklusa rada bagera utvrđena je razlika optimalne trajektorije kopanja u različitim materijalima. Predložena je klasifikacija učinka kopanja bagera u različitim materijalima. Također je predložen model za procjenu značajki materijala na temelju dinamičkih veličina rada bagera.The hydraulic excavator is one of the most commonly used machines in mining. Because of this, researchers have a great interest in studying its productivity and optimization of work. The research within this work is based on a detailed study of the operation of an excavator in real conditions. According to the available literature, such research is relatively modest and there is a lot of room for improvement. In order to access the data that provides insight into the real operation of the excavator, it is necessary to continuously measure the extension and pressures on the hydraulic cylinders. This is achieved by using a specific measuring system that can perform a simultaneous measurement of several parameters on the excavator during its work in real conditions. The measured data was processed using a computer program written in the Python programming language. Using standard kinematic and dynamic models of excavators, values of dynamic parameters of work (force, power, and energy consumption during digging) and geometric parameters of digging (tooth angle, length, and cutting area) were obtained. The field measurements were performed on 5 different machines and a total of 13 materials. Laboratory and field measurements determined the characteristics of the material (granulation, moisture content, and bulk density). In the paper, the productivity of digging was calculated, which represents the mass or volume of the excavated material in the time it took to perform the digging. In the frame of the statistical processing of data, multiple regression analyses have been performed on the influence of the characteristics of the material on the dynamic parameters of the excavator and the digging geometry. By regression analysis, the influence of the characteristics of the rocks and the geometry of digging on the productivity of digging are also shown. The size distribution has been found to be the most influential property of non-cohesive materials on the productivity of digging, while the length of the digging trajectory is the most influential geometric size. Through detailed analysis of the separate work cycles of the excavators, the difference in optimal digging trajectory in different materials has been determined. The classification of productivity of excavators digging in different materials is proposed. A model for assessing the characteristics of the materials based on the dynamic working parameters of the excavator is also proposed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Fires and explosions in underground exploitation : master's thesis
No full textU diplomskom radu su obrađene opasnosti u podzemnoj eksploataciji s naglaskom na požare i eksplozije. Navedeni su svi uzroci požara i eksplozija u rudarstvu, njihova prevencija i svladavanje. Koristeći programe Word i Excel iz Office paketa, statistički su obrađene nesreće u rudarstvu tijekom posljednjih 20 godina. Rezultati statističke obrade su prikazani u obliku dijagrama koji se odnose na smrtno stradale rudare u nesrećama, te uzroke i lokacije tih nesreća. U posljednjih 20 godina je kroz ovaj pregled ustanovljeno 3880 smrtno stradalih rudara, od kojih je najveća većina stradala od požara i eksplozija u ugljenokopima, što čini 3530 žrtava, odnosno 91 % svih stradalih. Postoje mnogi čimbenici koji utječu na sigurnost, te koji mogu biti reducirani, ali nikad u potpunosti eliminirani.The Master´s thesis deals with the dangers of underground exploitation with emphasis on fires and explosions. All causes of fires and explosions in mining, their prevention and control are listed. Using Word and Excel from the Office suite, mining accidents have been statistically analyzed over the last 20 years. The results of the statistical analysis are presented in the form of diagrams relating to the deaths of miners in accidents and the causes and locations of such accidents. Over the past 20 years, this survey has identified 3880 deceased miners, the largest majority of whom have been killed by fires and explosions in coal mines, accounting for 3530 casualties, or 91 % of all casualties. There are many factors that affect security that can be reduced but never completely eliminated
Analiza potrošnje goriva kamiona istresača na površinskom kopu Očura : završni rad
No full textU ovom radu izračunata je potrošnja goriva kamiona istresača na površinskom kopu Očura. Iz tvrtke su dobiveni podaci o trasama kretanja kamiona i ti podaci su obrađeni. Trase su podijeljene na dionice pomoću programa Google Earth Pro te je za svaku dionicu računato: otpor nagiba, otpor kotrljanja, radijus krivine, duljinu. Pomoću tih podataka i podataka koji su nađeni u brošuri tvrtke Bell o kamionima koji se koriste, računata je vučna sila pa je pomoću nje iščitana brzina kretanja kamiona. Zatim je računata potrebna snaga, brzine kretanja, koeficijent snage, vrijeme kretanja te na kraju potrošnju goriva. Rezultati rada su zadovoljavajući. Za trasu 1 potrošnja goriva iznosi 16,96428 kg/h , a za trasu 2 potrošnja iznosi 14,48 kg/h. Prava potrošnja goriva iznosi 12 kg/h
Assesment of the angle of cone in cylinder method testing : master’s thesis
Full text linkU ovom radu objašnjene su različite metode mjerenja kuta sipanja materijala. Pomoću kutomjera, podne šablone, 2D i 3D fotografije izvedena su mjerenja kuta te su opisane i metode formiranja kutova sipanja materijala. Za potrebe usporedbe mjerenja kutova korišteni su referentni stošci različitih kutova od 25°, 28°, 35°. Referentni stošci izrađeni su pomoću papira i 3D ispisivanjem. Mjerenja su izvršena i na stvarnoj gomili formiranoj pomoću metode cilindra. U radu su prikazani rezultati mjerenja kuta sipanja na referentnim stošcima, te na stvarnim hrpama. Poseban naglasak pri mjerenju kutova stavljen je na metodu 3D mjerenje kuta.This thesis describes different angle measuring methods of angle of repose. Angle measurements were performed with a usage of protractor, floor template, 2D and 3D photographs. For comparison, there were used reference cone of different angles 25°, 28°, 35°. Reference cones were made with paper and 3D printing while measurement were made on real pile formed by The cylinder method. In thesis are presented the results of measuring angles of repose and on real piles. When measuring angles a special emphasis was placed on 3D method of measuring angles
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