Milling of the optical surfaces

Tato bakalářská práce je orientována na mikrofrézování optických plošek prototypového světlometu sportovního automobilu. V práci jsou zvoleny nástroje pro mikrofrézování za užití vysokootáčkového vřetene. Byly navrženy různé řezné podmínky a na základě fotometrických testů byly vybrány optimální řezné podmínky.This bachelor thesis focuses on the micro-milling of the optical surfaces of the prototype headlamp of a sports car. The tools for micro-milling using the high-speed spindle are selected. Different and optimum cutting conditions based on photometric tests were chosen.632 - Katedra materiálů a technologií pro automobilyvelmi dobř

Optimizing Production for Selected Products to Increase Productivity at Hermle C32U Machining Center

PROKOP, J. Optimalizace výroby u vybraných výrobků s cílem zvýšení produktivity na obráběcích centrech Hermle C32U. Ostrava: VŠB – Technická univerzita Ostrava, Fakulta strojní, Katedra obrábění a montáže, 2018, 61 s. Vedoucí práce: Lichovník, J. Bakalářská práce pojednává o optimalizaci výroby na obráběcím centru Hermle C32U. Teoretickým rozborem daného problému. Návrh řešení dané problematiky, zlepšení výroby dvou zvolených zástupců nástrojů na této fréze vyráběných. Výrobě polotovarů pro nástroje, popis stávajícího stavu a úvaha za účelem jeho zlepšení. Provedení technicko-ekonomického zhodnocení optimalizace výroby, odstranění zbytečných časových mezer, snížení nákladů, navržení technických zlepšení. V závěru je provedeno shrnutí zjištěných údaju a analýza nákladů.PROKOP, J. Optimizing production for Selected Products to Increase Productivity a Hermle C32U Machining Center. Ostrava: VSB – Technical University of Ostrava, Faculty of Engineering, Department of Machining and Assembly 2018, 61p. Supervisor: Lichovník, J. Bachleor thesis deals with the optimalization of production at Hermle C32U Machining Center. Teoretical analysis of given problem. Proposal solution of given problematics, improving production of two selected machining tools on this Machining Centre manufactured. About production of semi-finished products for machining tools. Execution of technological-ekonomic evaluation of production optimalization, eliminating unnecessary downtimes, lowering of costs, proposing of technological improvements. In conclusion is done summary of achieved informations, and alalysis of costs.346 - Katedra obrábění, montáže a strojírenské metrologievýborn

Implementation of cover for motor-generator unit

Tato diplomová práce s názvem Realizace kapotáže motorgenerátorové jednotky má za cíl navrhnout a zkonstruovat kapotáž motorgenerátorové jednotky, výrobní dokumentaci a připravit jednotku pro používání. V kapitole Rešerše současné produkce motorgenerátorů je stručně charakterizován záložní zdroj energie, stav rozdělení motorgenerátorových jednotek a vhodný výběr jednotky dle požadavků. Mimo jiné je zde popsán stav „blackout“ a jeho možný negativní dopad na obyvatele. Následuje popis návrhu části jednoty a její realizace. Ve čtvrté části se věnuji funkčním požadavkům. Celou práci uzavírá shrnutí výsledků a závěr. Diplomová práce může sloužit jako zdroj informací při návrhu krytování motorgenerátorové jednotky.The thesis is entitled Implementation of cover for motor-generator unit. Its aim is to design and construct a motor generator unit hood, production documentation and prepare the unit for use. The chapter Searching the current production of motor generators briefly characterizes the backup energy source, the state of distribution of motor generator units and the appropriate selection of the unit according to requirements. Moreover, the state of "blackout" and its possible negative impact on the population is described here. The following part concerns a description of the design of part of the unity and its implementation. The fourth part deals with functional requirements. The whole work concludes with a summary of the results and a conclusion. The diploma thesis can serve as a source of information in the design of the motor generator unit cover.632 - Katedra materiálů a technologií pro automobilyvelmi dobř

Cylindrospermopsin biodegradation abilities of Aeromonas sp. isolated from Rusałka Lake

The occurrence of the cyanobacterial toxin cylindrospermopsin (CYN) in freshwater reservoirs is a common phenomenon. However, the biodegradation of this toxin in environmental samples has been observed only occasionally. In this work the biodegradation ability of cylindrospermopsin was investigated based on isolates from lakes with previous cyanotoxin history. Bacterial strains were identified based on the 16S rDNA and rpoD gene comparison. CYN biodegradation was monitored using the HPLC method. The R6 strain identified as Aeromonas sp. was documented as being capable of CYN removal. This biodegradation was dependent on the pH and temperature. Additionally, the stimulation of the growth of the R6 strain in the presence of CYN was indicated. Our discovery supports the hypothesis that (in analogy to the well-known phenomenon of microcystin biodegradation) in lakes dominated by potential CYN-producing cyanobacteria, the processes of microbial utilization of this toxin may occur

A comparative study on the removal of Pb(II), Zn(II), Cd(II) and As(V) by natural, acid activated and calcined halloysite

Trace elements like lead, zinc, cadmium and arsenic are among the most hazardous for the environment. They tend to accumulate in living organisms and exhibit carcinogenic or toxic properties. With the intensive development of the global industry these elements spread and infiltrate into soil and water, what results in contamination. Clay minerals play an important role in the environment as natural adsorbents. This is due to their ability of attracting ions from water solutions. The contaminants are accumulated by the structure of clay minerals, which leads to their immobilization. Halloysite is a clay mineral, belonging to the kaolin group minerals. Its structure is composed of stacked 1:1 layers built from octahedral (alumina) and tetrahedral (silica) sheets, linked through hydrogen bonds. Due to the fact that Poland has several kaolin deposits it is important to undertake research concerning possibility of using them as a natural scavenger of pollutants (Matusik & Bajda 2013, Matusik & Wścisło 2014). Thus, the purpose of the research was to investigate the sorption affinity of natural, acid activated and calcined halloysite toward Pb(II), Zn(II), Cd(II) and As(V). In the study three mineral samples were chosen: natural halloysite – H, acid activated halloysite – HA and calcined halloysite – HC. The H sample used in the study came from Polish deposit located in Dunino near Legnica which is owned and exploited by the Intermark company. The last two samples are produced by Intermark on an industrial scale, by modifying H sample. The materials were characterized using XRD and FTIR methods. Additionally the cation exchange capacity (CEC) and specific surface area (SBET) were measured. The CEC of tested materials were measured by adsorption of methylene blue. The SBET was determined on the basis of the low temperature nitrogen adsorption isotherm measured at -196°C and calculated in accordance with the Brunauer-Emmet-Teller (BET) methodology. The materials sorption affinity towards Pb(II), Zn(II), Cd(II) and As(V) was investigated. Experiments were carried out at pH 5. After mixing 50 mg of each material with 2.5 ml of appropriate solution (20 g/L - solid/solution ratio), sample portions were shaken for 24 h at room temperature to reach equilibrium. The concentration of metals – Pb(II), Cd(II) and Zn(II) in supernatant solutions was determined using AAS method while the As(V) was measured using colorymetric molybdenum blue method. The XRD pattern of the H sample showed a basal peak at 7.20 Å, which is attributed to dehydrated halloysite-7(Å). There were no significant changes in the XRD pattern of HC sample, which indicated that there were no serious changes in the clay structure due to calcined. In contrast, the XRD pattern of HA sample showed a decrease in intensity of ~7.20 Å peak of halloysite and the appearance of new peak at 7.63 Å was observed. Also, there were changes in the 19-25°2θ region, what is an effect of structural disorder caused by sulfuric acid treatment. It is worth notifying that the FTIR spectra of H and HC samples did not differ significantly. In turn, the bands changes for the HA are noticeable, which is in accordance with XRD results. After acid treatment the bands shape and intensity in 1300-1000 cm-1 region has changed indicating structural disorder of tethraedral sheet. The spectra revealed that the octahedral sheet and OH hydroxyls were not significantly altered. The HA sample exhibited the largest SBET (171.6 m2/g) while the SBET for the H sample was the lowest (49.5 m2/g). The calcination led to slight increase of SBET value to 52.1 m2/g in comparison to the H sample. The CEC results showed that differences between H (8.79 meq/100 g) and HC (8.19 meq/100 g) samples are insignificant, moreover the CEC of H sample is slightly higher. Such decrease can be explained by the loss of some the cation exchange sites, induced by heat treatment (Ho & Handy 1964). The enhancement in CEC was observed for the HA sample (10.69 meq/100 g). Sorption mechanism for raw halloysite can take place via ion-exchange and surface complexation through silanol Si-OH and aluminol Al-OH groups. The Pb(II) ions are more likely to hydrolyze and create PbOH+ forms, which may link to deprotonated groups. This process is called surface complexation. Heavy metals such as Zn(II) and Cd(II) tend to adsorb through ion-exchange. The adsorption behavior of tested heavy metals onto tested materials differs. The sorption capacity for H sample was found to follow the sequence As(V)>Pb(II)>Cd(II)>Zn(II). In the case of cations, this behavior reflects the cations hydrolysis constants, which are equal to 7.71, 8.96, and 10.08 respectively. The sorption capacity for H sample reached 168.4 mmol As/kg, 37.2 mmol Pb/kg, 3.7 mmol Cd/kg and 1.9 mmol Zn/kg. The sorption onto HC sample was found to be the following: Pb(II)≈Zn(II)>Cd(II)>As(V). Comparing sorption results for HC to the results for H sample, the increase of sorption for all tested heavy metals was observed. The sorption of cations reached an equilibrium equal to: 219 mmol Pb/kg, 212 mmol Zn/kg and 134.4 mmol Cd/kg. The sorption of As(V) decreased slightly in comparison to H sample. The acid activation resulted in an increase of active sites capable for Pb(II) adsorption and a decrease of active sites responsible for As(V) adsorption. Sorption equilibrium reached 235 mmol Pb/kg and 66 mmol As/kg. The results obtained for Zn(II) and Cd(II) indicated that sorption was not observed which may be due to lack of ion-exchange sites. The explanation of this behavior requires further studies. It is was worth to underline the highest sorption capacity of H sample towards As(V) which is most likely due to surface complexation. The results indicated that depending on the type of pollutants an appropriate type of halloysite-based sorbent needs to be chosen.   This project was supported by the Polish National Science Centre under research project awarded by decision No. DEC-2011/01/D/ST10/06814.Trace elements like lead, zinc, cadmium and arsenic are among the most hazardous for the environment. They tend to accumulate in living organisms and exhibit carcinogenic or toxic properties. With the intensive development of the global industry these elements spread and infiltrate into soil and water, what results in contamination. Clay minerals play an important role in the environment as natural adsorbents. This is due to their ability of attracting ions from water solutions. The contaminants are accumulated by the structure of clay minerals, which leads to their immobilization. Halloysite is a clay mineral, belonging to the kaolin group minerals. Its structure is composed of stacked 1:1 layers built from octahedral (alumina) and tetrahedral (silica) sheets, linked through hydrogen bonds. Due to the fact that Poland has several kaolin deposits it is important to undertake research concerning possibility of using them as a natural scavenger of pollutants (Matusik & Bajda 2013, Matusik & Wścisło 2014). Thus, the purpose of the research was to investigate the sorption affinity of natural, acid activated and calcined halloysite toward Pb(II), Zn(II), Cd(II) and As(V). In the study three mineral samples were chosen: natural halloysite – H, acid activated halloysite – HA and calcined halloysite – HC. The H sample used in the study came from Polish deposit located in Dunino near Legnica which is owned and exploited by the Intermark company. The last two samples are produced by Intermark on an industrial scale, by modifying H sample. The materials were characterized using XRD and FTIR methods. Additionally the cation exchange capacity (CEC) and specific surface area (SBET) were measured. The CEC of tested materials were measured by adsorption of methylene blue. The SBET was determined on the basis of the low temperature nitrogen adsorption isotherm measured at -196°C and calculated in accordance with the Brunauer-Emmet-Teller (BET) methodology. The materials sorption affinity towards Pb(II), Zn(II), Cd(II) and As(V) was investigated. Experiments were carried out at pH 5. After mixing 50 mg of each material with 2.5 ml of appropriate solution (20 g/L - solid/solution ratio), sample portions were shaken for 24 h at room temperature to reach equilibrium. The concentration of metals – Pb(II), Cd(II) and Zn(II) in supernatant solutions was determined using AAS method while the As(V) was measured using colorymetric molybdenum blue method. The XRD pattern of the H sample showed a basal peak at 7.20 Å, which is attributed to dehydrated halloysite-7(Å). There were no significant changes in the XRD pattern of HC sample, which indicated that there were no serious changes in the clay structure due to calcined. In contrast, the XRD pattern of HA sample showed a decrease in intensity of ~7.20 Å peak of halloysite and the appearance of new peak at 7.63 Å was observed. Also, there were changes in the 19-25°2θ region, what is an effect of structural disorder caused by sulfuric acid treatment. It is worth notifying that the FTIR spectra of H and HC samples did not differ significantly. In turn, the bands changes for the HA are noticeable, which is in accordance with XRD results. After acid treatment the bands shape and intensity in 1300-1000 cm-1 region has changed indicating structural disorder of tethraedral sheet. The spectra revealed that the octahedral sheet and OH hydroxyls were not significantly altered. The HA sample exhibited the largest SBET (171.6 m2/g) while the SBET for the H sample was the lowest (49.5 m2/g). The calcination led to slight increase of SBET value to 52.1 m2/g in comparison to the H sample. The CEC results showed that differences between H (8.79 meq/100 g) and HC (8.19 meq/100 g) samples are insignificant, moreover the CEC of H sample is slightly higher. Such decrease can be explained by the loss of some the cation exchange sites, induced by heat treatment (Ho & Handy 1964). The enhancement in CEC was observed for the HA sample (10.69 meq/100 g). Sorption mechanism for raw halloysite can take place via ion-exchange and surface complexation through silanol Si-OH and aluminol Al-OH groups. The Pb(II) ions are more likely to hydrolyze and create PbOH+ forms, which may link to deprotonated groups. This process is called surface complexation. Heavy metals such as Zn(II) and Cd(II) tend to adsorb through ion-exchange. The adsorption behavior of tested heavy metals onto tested materials differs. The sorption capacity for H sample was found to follow the sequence As(V)>Pb(II)>Cd(II)>Zn(II). In the case of cations, this behavior reflects the cations hydrolysis constants, which are equal to 7.71, 8.96, and 10.08 respectively. The sorption capacity for H sample reached 168.4 mmol As/kg, 37.2 mmol Pb/kg, 3.7 mmol Cd/kg and 1.9 mmol Zn/kg. The sorption onto HC sample was found to be the following: Pb(II)≈Zn(II)>Cd(II)>As(V). Comparing sorption results for HC to the results for H sample, the increase of sorption for all tested heavy metals was observed. The sorption of cations reached an equilibrium equal to: 219 mmol Pb/kg, 212 mmol Zn/kg and 134.4 mmol Cd/kg. The sorption of As(V) decreased slightly in comparison to H sample. The acid activation resulted in an increase of active sites capable for Pb(II) adsorption and a decrease of active sites responsible for As(V) adsorption. Sorption equilibrium reached 235 mmol Pb/kg and 66 mmol As/kg. The results obtained for Zn(II) and Cd(II) indicated that sorption was not observed which may be due to lack of ion-exchange sites. The explanation of this behavior requires further studies. It is was worth to underline the highest sorption capacity of H sample towards As(V) which is most likely due to surface complexation. The results indicated that depending on the type of pollutants an appropriate type of halloysite-based sorbent needs to be chosen. This project was supported by the Polish National Science Centre under research project awarded by decision No. DEC-2011/01/D/ST10/06814

New dustywings (Neuroptera, Coniopterygidae) from mid-Cretaceous amber of Myanmar reveal spectacular diversity

Two new genera and species of Coniopterygidae (Neuroptera) are described and illustrated from mid Cretaceous (Cenomanian) amber of Myanmar. Mulleroconis hyalina gen. n. et sp. n., attributed to the Coniopteryginae, bears a unique combination of venation characters and an abdomen without plicatures. The second new genus, attributed to the Aleuropteryginae, i.e. Palaeoconis azari gen. n. et sp. n., displays a unique pattern of crossveins 1m-cua and 2mp2-cua, with the latter crossing the pigmented spot. A check-list of all fossil genera and species of Coniopterygidae is provided

La parcimonie de Wagner sur base de caractères morphologiques: une nouvelle méthode pour les études paléosynécologiques

The limits and difficulties related to the tools currently in use for palaeosynecological comparisons of faunas or floras of different geological periods are discussed. The new method of the Wagner parsimony Applied to Palaeosynecology Using Morphology (WAPUM method), is defined and tested on morphological characters gathered from two insect groups Odonatoptera and Thripida. The difficulties related to the monophyly of the taxonomic groups used in the more traditional approaches are no longer a problem when using the WAPUM method. In the WAPUM a character is ‘presence versus absence of species bearing a morphological structure’. The results obtained from use of the WAPUM minimize the number of changes among character states. Application of the WAPUM could reveal signals to confirm or object the currently available scenarios for the global changes in the evolution of past diversity and disparity of organisms (major changes or global crises of diversity).Les limites et difficultés inhérentes aux outils actuellement utilisés dans les comparaisons paléosynécologiques de faunes ou de flores de différentes périodes géologiques sont discutées. La nouvelle méthode de la parsimonie de Wagner appliquée à la paléosynécologie sur la base de caractères morphologiques (méthode WAPUM), est définie et testée à partir des caractères morphologiques de deux groupes d’insectes, les Odonatoptera et les Thripida. Les difficultés liées à la monophylie des groupes taxonomiques utilisés dans les approches plus traditionnelles disparaissent avec la méthode WAPUM. Dans l’approche WAPUM, un caractère est ‘présence/absence d’une espèce portant une structure morphologique’. Les résultats obtenus à partir de la méthode WAPUM minimisent le nombre de changements d’état de caractères. Cet outil permet de tester les scénarios actuellement disponibles pour les changements globaux dans l’évolution de la diversité et de la disparité passée des organismes (changements majeurs ou crises globales de la diversité).Museo de La Plat

Removal of selected anions by raw halloysite and smectite clay

The structure of clay minerals is made up from tetrahedral and octahedral sheets, which can be stacked in different ways, forming 1:1, 2:1 and 2:1:1 layers. Halloysite, which belongs to the kaolin group, is composed of 1:1 layers while smectite group minerals exhibit 2:1 dioctahedral layered structure. The most important feature of these minerals is the presence of numerous active centers on their surface and/or in the interlayer space, which allows them to attract and exchange ions from aqueous solutions. These makes them perfect candidates which could be used for the purification of wastewaters from harmful ions (Bhattacharyya & Gupta 2008; Lee & Tiwari 2012). The aim of this work was to examine the sorption capacity of natural halloysite and smectite clay towards P(V), As(V) and Cr(VI). Two samples used in the research came from Polish deposits. Natural halloysite (H) was obtained from Dunino deposit, while smectite clay (SC) was obtained from Bełchatów Lignine Mine where it forms an overburden cover. For the both raw samples the XRD patterns and FTIR spectra were collected. The sorption of P(V), As(V) and Cr(VI) was conducted as a function of anions concentration in the range from 0.05 to 50 mmol/L for initial pH 5 in a single-element system. The suspension of H or SC and an adequate solution (solid/solution ratio: 20 g/L) was shaken for 24 h at 25°C. Afterwards the anions concentration in the supernatant solution was measured using colorimetric methods. The P(V) and As(V) concentration was determined with molybdenum blue method, while Cr(VI) concentration was measured with diphenylcarbazide method. The XRD pattern of the H sample showed a basal peak at 7.20 Å, which confirms the presence of dehydrated halloysite-(7 Å). In turn, the SC exhibited a peak centered at ~12.5 Å with an asymmetric profile starting from ~15.0 Å. Such reflection suggests the presence of smectite which has both Na+ and Ca2+ cations in its interlayer space. The peaks at 4.26 Å and 3.34 Å are associated with quartz. The IR spectra of the H showed bands characteristic for kaolin group minerals related to the OH-stretching region (3700-3620 cm-1), vibrations of water molecules (~1630 cm-1) and bands assigned to stretching and bending vibrations of aluminosilicate framework (1200-400 cm-1). The IR spectrum of SC shows bands characteristic for smectite minerals i.e. 3623 cm-1 band attributed to OH hydroxyl located inside the 2:1 layer and a broad band centered at ~3400 cm-1 due to interlayer water surrounding cations. Also the structural vibrations of the 2:1 layer may be observed in the 1200-400 cm-1 region. The results of the experiment indicated that the sorption capacity of the H sample and the SC sample were relatively high. The amount of removed P(V) was the highest for both materials, where the sorption was respectively equal to: 201 and 256 mmol/kg. The sorption capacity of As(V) for the H was equal to 168 mmol/kg, while it was significantly lower on the SC (96 mmol/kg). In the case of H the Cr(VI) sorption reached only 36 mmol/kg and for the SC it was equal to 104 mmol/kg. In most cases the sorption isotherms were fitted to the Freundlich model. The only exception was for P(V) sorption on the H sample, which was better described by Langmuir model. The specific surface areas (SBET) of the studied materials do not differ significantly: SC = 69.10 m2/g and H = 49.52 m2/g. The sorption centers that may attract anions in both, H and SC samples, were limited, because isomorphic substitutions in tetrahedral and/or octahedral sheets generate positively charged sites, which attract cations. It is believed that the mechanism responsible for the adsorption of anions on both materials is mainly surface complexation, which occurs at the crystals edges (Bradl 2004). The sorption capacity of the H and the SC was significantly lower than that reported for hydrotalcite-based anion-exchange materials (HTLc). For comparison, the sorption capacity towards P(V), As(V) and Cr(VI) on uncalcined HTLc was as follows: 498 mmol/kg (Kuzawa et al. 2006), 596 mmol/kg (Wu et al. 2013) and 314 mmol/kg (Alvarez-Ayuso & Nugteren 2005). Nevertheless, the examined mineral samples might be useful as sorbents for industrial wastewater treatment involving the removal of P(V) and As(V)