ORIGINAL_ARTICLEBesides the outer shell, it is the internal structures that contribute the most to the mechanical integrity of an additively manufactured component. In order to investigate the influence of the geometrically different internal structures and infill density on the Young’s modulus, tensile strength and failure strain, tensile specimens of polylactic Acid (PLA) were prepared using fused deposition modeling and tested at room temperature. There was a significant influence of the infill density, the manufacturing process and the resulting microstructure on the mechanical properties. In summary, the position of the microstructure relative to the load direction is found to be a significant factor of influence.https://acc-ern.tul.cz/archiv/PDF/ACC_2021_1_01.pdf2021-06-3071610.15240/tul/004/2021-1-001Fused deposition modelingPLAInfillTensile testMechanical propertiesMicrostructureWolfgangFörsterwolfgang.foerster@ba-sachsen.de1Berufsakademie Sachsen, Staatliche Studienakademie Glauchau, Industrielle ProduktionAUTHORThomasPucklitzschthomas.pucklitzsch@ba-sachsen.de2Berufsakademie Sachsen, Staatliche Studienakademie Glauchau, Industrielle ProduktionAUTHORDanielaNickeldaniela.nickel@ba-sachsen.de3Berufsakademie Sachsen, Staatliche Studienakademie Glauchau, Industrielle ProduktionAUTHORALAFAGHANI, A.; QATTAWI, A.; ALRAWI, B.; GUZMAN, A.: Experimental Optimization of Fused Deposition Modelling Processing Parameters: A Design-forManufacturing Approach. Procedia Manufacturing110.1016/j.promfg.2017.07.079LUZANIN, O.; MOVRIN, D.; PLANCAK, M.: Effect of layer thickness, deposition angle, and infill on maximum flexural force in FDM-built specimens. Journal for Technology of Plasticity. 2014, Vol. 39, Issue 1, pp. 49–57. ISSN 0354-3870.2ALAFAGHANI, A.; QATTAWI, A.: Investigating the effect of fused deposition modeling processing parameters using Taguchi design of experiment method. Journal of Manufacturing Processes.310.1016/j.jmapro.2018.09.025FERNANDEZ-VICENTE, M.; CALLE, W.; FERRANDIZ, S.; CONEJERO, A.: Effect of Infill Parameters on Tensile Mechanical Behavior in Desktop 3D Printing. 3D Printing and Additive Manufacturing.410.1089/3dp.2015.0036JOHNSON, G. A.; FRENCH, J. J.: Evaluation of Infill Effect on Mechanical Properties of Consumer 3D Printing Materials. Advances in Technology Innovation. 2018, Vol. 3, Issue 4, pp. 179–184. ISSN 2415-0436. e-ISSN 2518-2994.5RODRÍGUEZ-PANES, A.; CLAVER, J.; CAMACHO, A. M.: The Influence of Manufacturing Parameters on the Mechanical Behaviour of PLA and ABS Pieces Manufactured by FDM: A Comparative Analysis. Materials.610.3390/ma11081333RISMALIA, M.; HIDAJAT, S. C.; PERMANA, I. G. R.; HADISUJOTO, B.; MUSLIMIN, M.; TRIAWAN, F.: Infill pattern and density effects on the tensile properties of 3D printed PLA material. Journal of Physics: Conference Series.710.1088/1742-6596/1402/4/044041PANDZIC, A.; HODZIC, D.; MILOVANOVIC, A.: Effect of Infill Type and Density on Tensile Properties of PLA Material for FDM Process. In: Katalinic, B. (ed.), Proceedings of the 30th DAAAM International Symposium on Intelligent Manufacturing and Automation. DAAAM International, Vienna, Austria, 2019, pp. 0545–0554. ISBN 978-3-902734-22-8. ISSN 1726-9679810.2507/30th.daaam.proceedings.074CHACÓN, J. M.; CAMINERO, M. A.; GARCÍA-PLAZA, E.; NÚÑEZ, P. J.: Additive manufacturing of PLA structures using fused deposition modelling: Effect of process parameters on mechanical properties and their optimal selection. Materials & Design.910.1016/j.matdes.2017.03.065SUKINDAR, N. A. B.; ARIFFIN, M. K. A. B. M.; BAHARUDIN, B. T. H. T. B.; JAAFAR, C. N. A. B.; ISMAIL, M. I. S. B.: Analysis on the impact process parameters on tensile strength using 3D printer repetier-host software. ARPN Journal of Engineering and Applied Sciences. 2017, Vol. 12, Issue 10, pp. 3341–3346. ISSN 1819- 6608.10KOTLINSKI, J.: Mechanical properties of commercial rapid prototyping materials. Rapid Prototyping Journal.1110.1108/RPJ-06-2012-0052LANZOTTI, A.; GRASSO, M.; STAIANO, G.; MARTORELLI, M.: The impact of process parameters on mechanical properties of parts fabricated in PLA with an opensource 3-D printer. Rapid Prototyping Journal.1210.1108/RPJ-09-2014-0135

ORIGINAL_ARTICLEThe Gottesacker (“God’s acre”) in Herrnhut (Upper Lusatia, Saxony) has been a graveyard for almost 300 years. G. ZSCHIESCHANG has mapped its fungal community since the 1960ies. Combining these findings and those of other mycologists, mycological data that cover about 55 years are reported here. In this context, we discuss the fungal biodiversity with special emphasis on CHEGD species (Clavariaceae-Hygrocybe-Entoloma-Geoglossaceae-Dermoloma). These species are used to classify and assess the conservation value of grasslands by monitoring their fungal communities. According to the determined CHEGD profile, the Gottesacker graveyard is ranked as a grassland of international importance. In addition, we present macroscopic and microscopic characteristics of two rare CHEGD species: Entoloma brunneosericeum and Clavaria messapica. These are the first records of both species for Germany and Saxony, respectively.https://acc-ern.tul.cz/archiv/PDF/ACC_2021_1_02.pdf2021-06-30172810.15240/tul/004/2021-1-002CHEGDClavaria messapicaEntoloma brunneosericeumHygrocybeBiodiversityFungiAlexanderKarichalexander.karich@tu-dresden.de1TU Dresden, International Institute Zittau, Department of Bio- and Environmental SciencesAUTHORRenéUllrichrene.ullrich@tu-dresden.de2TU Dresden, International Institute Zittau, Department of Bio- and Environmental SciencesAUTHORMartinHofrichtermartin.hofrichter@tu-dresden.de3TU Dresden, International Institute Zittau, Department of Bio- and Environmental SciencesAUTHORCARDINALE, B. J.; DUFFY, J. E.; GONZALEZ, A.; HOOPER, D. U.; PERRINGS, Ch.; VENAIL, P.; NARWANI, A.; MACE, G. M.; TILMAN, D.; WARDLE, D. A.; KINZIG, A. P.; DAILY, G. C.; LOREAU, M.; GRACE, J. B.; LARIGAUDERIE, A.; SRIVASTAVA, D. S.; NAEEM, S.: Biodiversity loss and its impact on humanity. Nature. DOI: 10.1038/nature111481GRIFFITH, G. W.; GAMARRA, J. G. P.; HOLDEN, E. M.; MITCHEL, D.; GRAHAM, A.; EVANS, D. A.; EVANS, S. E.; ARON, C.; NOORDELOOS, M. E.; KIRK, P. M.; SMITH, S. L. N.; WOODS, R. G.; HALE, A. D.; EASTON, G. L.; RATKOWSKY, D. A.; STEVENS, D. P.; HALBWACHS, H.: The international conservation importance of Welsh ‘waxcap’ grasslands. Mycosphere. 210.5943/mycosphere/4/5/10HALBWACHS, H.; KARASCH, P.; GRIFFITH, G. W.: The diverse habitats of Hygrocybe – peeking into an enigmatic lifestyle. Mycosphere. 310.5943/mycosphere/4/4/14HALBWACHS, H.; EASTON, G. L.; BOL, R.; HOBBIE, E. A.; GARNETT, M. H.; PERŠOH, D.; DIXON, L.; OSTLE, N.; KARASCH, P.; GRIFFITH, G.W.: Isotopic evidence of biotrophy and unusual nitrogen nutrition in soil‐dwelling Hygrophoraceae. Environmental Microbiology.410.1111/1462-2920.14327RUTHSATZ, B.: Was haben Pilze wie die Saftlinge (Gattung Hygrocybe s. l.) auf magerem Grünland zu suchen? Tuexenia.510.14471/2018.38.007TELLO, S. A.; SILVA-FLORES, P.; AGERER, R.; HALBWACHS, H.; BECK, A.; PERŠOH, D.: Hygrocybe virginea is a systemic endophyte of Plantago lanceolata. Mycological Progress. 610.1007/s11557-013-0928-0KARICH, A.; KELLNER, H.; SCHMIDT, M.; ULLRICH, R.: Ein bemerkenswertes Mykotop im Zittauer Gebirge mit Microglossum rufescens als Erstnachweis für Deutschland. Boletus. 2015, Vol. 36, Issue 2, pp. 151–163.7DÖRFELT, H.; HEKLAU, H.: Die Geschichte der Mykologie. Einhorn-Verlag Dietenberger, Schwäbisch Gmünd, 1998. ISBN 3927654442.8NCBI: GenBank. [online]. 2021. [accessed 2021-03-09]. Available from WWW: https://www.ncbi.nlm.nih.gov/9NILSSON, R. H.; LARSSON, K.-H.; TAYLOR, A. F. S.; BENGTSSON-PALME, J.; JEPPESEN, T. S.; SCHIGEL, D.; KENNEDY, P.; PICARD, K.; GLÖCKNER, F. O.; TEDERSOO, L.; SAAR, I.; KÕLJALG, U.; ABARENKOV, K.: The UNITE database for molecular identification of fungi: handling dark taxa and parallel taxonomic classifications. Nucleic Acids Research. 1010.1093/nar/gky1022DGfM: Pilze Deutschlands. [online]. 2021. [accessed 2021-03-09]. Available from WWW: http://www.pilze-deutschland.de/11VILA, J.; CARBÓ, J.; CABALLERO, F.; CATALÀ, S.; LLIMONA, X.; NOORDELOOS, M. E.: A first approach to the study of the genus Entoloma subgenus Nolanea s.l. using molecular and morphological data. Fungi non Delineati. 2013, Vol. 66 (Studies on Entoloma): Edizioni Candusso, Alassio. ISSN 1128-6008.12DONDL, M.: Hias’ Schwammerlseiten: Entoloma: Nr. 13: Entoloma brunneosericeum Noordel., Vila, F. Caball. & E. Suárez. [online]. 2021. [accessed 2021-03-09]. Available from WWW: http://www.interhias.de/schwammerlseiten/bestimmungen/2014/entoloma/entoloma.htm l#ank1313AGNELLO, C.; KAUTMANOVÁ, I.; CARBONE, M.: Clavaria messapica, una nuova specie del sud della Puglia. Rivista di Micologia. 2014, Vol. 3, pp. 195–210.14KARICH, A.; ULLRICH, R.: Lamelloclavaria petersenii, a Clavariaceae with agaric hymenophor-First German record. Boletus. 2019, Vol. 40, Issue 1, pp. 17–23.15JÜLICH, W.: Die Nichtblätterpilze, Gallertpilze und Bauchpilze. VEB Gustav Fischer Verlag, Jena, 1984. ISBN 3437202820.16KNUDSEN, H.; SHIRYAEV, A. G.; KAUTMANOVÁ I.: Clavaria L.: Fr. In: Knudsen H.; Vesterholt J. (eds), Funga Nordica, 2nd edition. 2018. ISBN 9788798396130.17CORNER, E. J. H.: A Monograph of Clavaria and Allied Genera. Oxford University Press, London, 1950. ISBN 8121104602.18ARNOLDS, E. J. M.: Ecology and coenology of macrofungi in grasslands and moist heathlands in Drenthe, the Netherlands. J. Cramer im AR Grantner Verlag Vaduz, 1981. ISBN 9783768213141.19NITARE, J.: Jordtungor, en svampgrupp pa tillbakagang i naturligafodermarker. Svensk Botanisk Tidskrift. 1988, Vol. 82, pp. 341–368.20RALD, E.: Vokshatte som indikatorarter for mykologisk vaerdifulde overdrevslokaliteter. Svampe. 1985, Vol. 11, pp. 1–9.21ROTHEROE, M.: Mycological survey of selected semi-natural grasslands in Carmarthenshire. Contract Science Report No. 340. Countryside Council for Wales, Bangor, 1999.22LEGON, N. W.; HENRICI, A.: Checklist of the British & Irish Basidiomycota. Royal Botanic Gardens, Kew, 2005. ISBN 1842461214.23KOBAYASHI, H.; HATANO, K.: A morphological study of the mycorrhiza of Entoloma clypeatum f. hybridum on Rosa multiflora. Mycoscience.2410.1007/BF02463979NOORDELOOS, M. E.: Entoloma, s.l. (Fungi Europaei 5). Libreria editrice Giovanna Biella, Saronno, 1992.25CORNER, E. J. H.: Supplement to “A Monograph of Clavaria and allied Genera”. Nova Hedwigia, Beihefte, Vol. 33, 1970. ISBN 978-3-768-25433-5.26LÜDERITZ, M.: Kooperation im mykologischen Artenschutz – Hotspot auf Fehmarn entdeckt. In: Jahresbericht 2016 zur biologischen Vielfalt – Jagd- und Artenschutz. Ministerium für Energiewende, Landwirtschaft, Umwelt und ländliche Räume des Landes Schleswig Holstein, Kiel, Germany, 2016.27BOERTMANN, D.: The genus Hygrocybe. 2 nd revised edition (Fungi of nordern Europe Vol. 1). Narayana Press, Roskilde, 2010. ISBN 9788798358176.28KUČERA, V.; LIZOŇ, P.; TOMŠOVSKÝ, M.; KUČERA, J.; GAISLER, J.: Reevaluation of the morphological variability of Microglossum viride and M. griseoviride sp. nov. Mycologia. 2910.3852/106.2.282KUČERA, V.; LIZOŇ, P.; TOMŠOVSKÝ, M.: Taxonomic divergence of the green naked-stipe members of the genus Microglossum (Helotiales). Mycologia,3010.1080/00275514.2016.1274620NOORDELOOS, M. E.: Entoloma s.l. Supplemento. Massimo Candusso, Alassio, 2004. ISBN 9788890105746.31LUDWIG, E.: Pilzkompendium, Bd. 2: Beschreibungen. Die größeren Gattungen der Agaricales mit farbigem Sporenpulver (ausgenommen Cortinariaceae). Fungicon Verlag. Berlin, 2007. ISBN 9783940316011.32KOKKONEN, K.: A survey of boreal Entoloma with emphasis on the subgenus Rhodopolia. Mycological Progress. 3310.1007/s11557-015-1135-yCLÉMENÇON, H.: Taxonomische und nomenklatorische Notizen zur Gattung Camarophyllus. Schweizer Zeitschrift für Pilzkunde. 1979, Vol. 57, Issue 8, pp. 113– 118.34CLÉMENÇON, H.: Kompendium der Blätterpilze: Camarophyllus. Beihefte zur Zeitschrift für Mykologie. 1982, Vol. 4, pp. 39–56.35HARDTKE, H. J.: Interessante weissliche Camarophyllus-Arten. Mykologisches Mitteilungsblatt. 1985, Vol. 28, pp. 43–46.36CANDUSSO, M.: Hygrophorus s.l. (Fungi Europaei 6). Candusso Edizioni, Alassio, 1997.37WHITE, T. J.; BRUNS, T.; LEE, S.; TAYLOR, J.: Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In: Innis, M. A.; Gelfand, D. H.; Sninsky, J. J.; White, T. J. (eds.), PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990. pp. 315–322.3810.1016/B978-0-12-372180- 8.50042-1

ORIGINAL_ARTICLEA vibration having a character of self-excited chatter oscillation known from machine tools is observed during intermittent motion of ink rollers of offset printing machines. This vibration occurs under specific operating conditions and is often accompanied by an increased noise level. To explain this unusual vibration behavior, a simple analytical model of two rollers interaction is derived. The calculated oscillation is compared with the measurement of ductor roller displacement. The model results confirm the possibility of self-excited vibration development in the presence of viscous forces, negative damping effects and continuous supply of external energy from roller rotation.https://acc-ern.tul.cz/archiv/PDF/ACC_2021_1_03.pdf2021-06-30293610.15240/tul/004/2021-1-003Self-excited oscillationViscous friction forceNegative dampingOffset printing machineMartinPustkamartin.pustka@vuts.cz1VÚTS, a.s., Measurement Department,AUTHORPavelŠidlofpavel.sidlof@vuts.cz2VÚTS, a.s., Measurement Department,AUTHORKIPPHAN, H. (ed.): Handbook of Print Media: Technologies and Production Methods. Springer-Verlag Berlin Heidelberg, 2001. ISBN 978-3-540-67326-2. eBook ISBN 978- 3-540-29900-4. 110.1007/978-3-540-29900-4QUINTANA, G.; CIURANA, J.: Chatter in machining processes: A review. International Journal of Machine Tools and Manufacture. 2011, Vol. 51, Issue 5, pp. 363–376.210.1016/j.ijmachtools.2011.01.001TONDL, A.: To the problem of self-excited vibration suppression. Engineering Mechanics. 2008, Vol. 15, Issue 4, pp. 297–307. Available from WWW: http://www.engineeringmechanics.cz/pdf/15_4_297.pdf3BREPTA, R.; PŮST, L.; TUREK, F.: Mechanické kmitání. Sobotáles, Praha, 1994. ISBN-13 978-80-901684-8-0. ISBN 80-901684-8-5.4CHHABRA, R. P.: Non-Newtonian Fluids: An Introduction. In: Krishnan J.; Deshpande A.; Kumar P. (eds), Rheology of Complex Fluids. Springer, New York, NY, 2010, pp. 3–34. ISBN 978-1-4419-6493-9. Online ISBN 978-1-4419-6494-6.510.1007/978-1-4419-6494-6_1