On the length of chains of proper subgroups covering a topological group

We prove that if an ultrafilter L is not coherent to a Q-point, then each analytic non-sigma-bounded topological group G admits an increasing chain <G_a : a of its proper subgroups such that: (i) U_{a in b(L)} G_a=G; and $(ii)$ For every sigma-bounded subgroup H of G there exists a such that H is a subset of G_a. In case of the group Sym(w) of all permutations of w with the topology inherited from w^w this improves upon earlier results of S. Thomas

THE INFLUENCE OF VARIOUS PRINT PARAMETERS ON THE MECHANICAL PROPERTIES OF TEST SPECIMENS PRODUCED BY FDM TECHNOLOGY

Tema ovog završnog rada je utjecaj različitih parametara ispisa na mehanička svojstva probnih uzoraka izrađenih FDM tehnologijom. Korištena su 3 materijala za 3D ispis pomoću FDM tehnologije, te je tako izrađeno 27 epruveta. Promatrale su se epruvete koje su isprintane pomoću 3D printera Prusa i3 MK2 sa ispunama od 15%, 45% i 75% , te utjecaj postotka ispune epruvete na njezinu vlačnu čvrstoću. Razlog odabira navedene teme je sve veći rast i napredak korištenja aditivnih tehnologija, s naglaskom na FDM tehnologiju budući se u praksi često možemo susresti sa 3D printerima namijenjenim upravo za taj postupak izrade modela. Takav printer zauzima vrlo malo mjesta, može koristiti razne vrste materijala, jednostavan je za korištenje, te se na tržištu može naći po prihvatljivoj cijeni. Kao i sve aditivne tehnologije zanimljiv je jer može izraditi prototip ili malu seriju modela sa izrazito kompliciranom geometrijom, odnosno ono što se nacrta u CAD programu vrlo brzo se može imati u opipljivom obliku čime se štedi vrijeme i novac. U teorijskom dijelu ovog rada opisana je aditivna proizvodnja, povijest i tehnologije. Naglasak je na FDM tehnologiji koja se koristi u eksperimentalnom dijelu. Također, zbog sve češćeg korištenja aditivnih tehnologija, naglasak je stavljen i na utjecaj materijala na ekologiju. U eksperimentalnom dijelu ispitana su 3 materijala koja se najčešće koriste za 3D ispis FDM tehnologijom. PLA, PETG, te materijal V. generacije FACILAN C8 – mješavina na bazi PLA. Pratio se utjecaj promjene parametara ispisa ispune epruvete na njenu vlačnu čvrstoću. Na kraju rada analizirani su podaci dobiveni ispitivanjem, te je donesen zaključak.The subject of this thesis is the influence of different print parameters on the mechanical properties of test samples made with FDM technology. 3 materials for 3D printing were used to produce 27 test specimens. These specimens were printed using 3D printer Prusa i3 MK2 with infill of 15%, 45%, and 75% and the influence of the infill percentage on its tensile strength was observed. The reason for choosing this topic is the increasing growth and advancement of the use of additive technologies, with an emphasis on FDM technology, since in practice we can often encounter 3D printers designed specifically for this model making process. Such a printer takes up very little space, can use various types of materials, is easy to use, and can be found on the market at an affordable price. Like all additive technologies, it is interesting because it can produce a prototype or a small series of models with extremely complicated geometry. What is drawn in a CAD program very quickly can be in tangible form, saving time and money. The theoretical part of this paper describes additive manufacturing, history and technologies. The emphasis is on FDM technology used in the experimental section. Also, due to the increased use of additive technology, emphasis is also placed on material impact on the ecology. In the experimental part we tested three materials that are commonly used for 3D printing FDM technology. PLA, PETG, and V-generation FACILAN C8 - PLA based blend. The effect of changing the print parameters of the test samples filling on its tensile strength was monitored. At the end of the paper, the test data were analyzed and a conclusion was reached

Model-Theoretic Properties of Countable Ultraproducts Without the Continuum Hypothesis.

We examine model-theoretic properties of U-Prod N where U is a non-principal ultrafilter on w, and N is the structure w together with all its finitary functions and relations. This structure is w(,1)-saturated, hence saturated if CH holds. We examine what can occur in models of ZFC + ('(NOT))CH. The first model we consider is the one obtained by adding k (GREATERTHEQ) w(,2) Cohen reals to a model of ZFC + GCH. Here, we show that for all regular uncountable cardinals a,b (LESSTHEQ) k there exist ultrafilters U(,a,b) such that the non-st and ard part of U-Prod(w, w(,w), there will be continuum many of these. Moreover when k (GREATERTHEQ) w(,3) we can get continuum many ultrafilters whose ultraproducts of (w,+,*) are non-isomorphic. (Under CH, all such ultraproducts are isomorphic). We also consider the model obtained by adding k (GREATERTHEQ) w(,2) r and om reals to a model of ZFC + GCH. It is easy to see that all ultraproducts in this model will have cofinality = w(,1), which precludes saturation. We prove the existence of ultraproducts with the following saturation property: they consist of a saturated model of the theory of N plus a top sky. The properties of these ultrafilters are discussed. This seems to be the maximal amount of saturation possible in this model: There are Dedekind cuts in the top sky of every ultraproduct where the cofinality of the lower segment and the coinitiality of the upper segment are both w(,1). Also we show that in this model there are, for any uncountable regular a, ultrafilters U such that a is the coinitiality of the non-st and ard part of U-Prod(w,<).Ph.D.MathematicsUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/158962/1/8224919.pd

THE INFLUENCE OF VARIOUS PRINT PARAMETERS ON THE MECHANICAL PROPERTIES OF TEST SPECIMENS PRODUCED BY FDM TECHNOLOGY

Tema ovog završnog rada je utjecaj različitih parametara ispisa na mehanička svojstva probnih uzoraka izrađenih FDM tehnologijom. Korištena su 3 materijala za 3D ispis pomoću FDM tehnologije, te je tako izrađeno 27 epruveta. Promatrale su se epruvete koje su isprintane pomoću 3D printera Prusa i3 MK2 sa ispunama od 15%, 45% i 75% , te utjecaj postotka ispune epruvete na njezinu vlačnu čvrstoću. Razlog odabira navedene teme je sve veći rast i napredak korištenja aditivnih tehnologija, s naglaskom na FDM tehnologiju budući se u praksi često možemo susresti sa 3D printerima namijenjenim upravo za taj postupak izrade modela. Takav printer zauzima vrlo malo mjesta, može koristiti razne vrste materijala, jednostavan je za korištenje, te se na tržištu može naći po prihvatljivoj cijeni. Kao i sve aditivne tehnologije zanimljiv je jer može izraditi prototip ili malu seriju modela sa izrazito kompliciranom geometrijom, odnosno ono što se nacrta u CAD programu vrlo brzo se može imati u opipljivom obliku čime se štedi vrijeme i novac. U teorijskom dijelu ovog rada opisana je aditivna proizvodnja, povijest i tehnologije. Naglasak je na FDM tehnologiji koja se koristi u eksperimentalnom dijelu. Također, zbog sve češćeg korištenja aditivnih tehnologija, naglasak je stavljen i na utjecaj materijala na ekologiju. U eksperimentalnom dijelu ispitana su 3 materijala koja se najčešće koriste za 3D ispis FDM tehnologijom. PLA, PETG, te materijal V. generacije FACILAN C8 – mješavina na bazi PLA. Pratio se utjecaj promjene parametara ispisa ispune epruvete na njenu vlačnu čvrstoću. Na kraju rada analizirani su podaci dobiveni ispitivanjem, te je donesen zaključak.The subject of this thesis is the influence of different print parameters on the mechanical properties of test samples made with FDM technology. 3 materials for 3D printing were used to produce 27 test specimens. These specimens were printed using 3D printer Prusa i3 MK2 with infill of 15%, 45%, and 75% and the influence of the infill percentage on its tensile strength was observed. The reason for choosing this topic is the increasing growth and advancement of the use of additive technologies, with an emphasis on FDM technology, since in practice we can often encounter 3D printers designed specifically for this model making process. Such a printer takes up very little space, can use various types of materials, is easy to use, and can be found on the market at an affordable price. Like all additive technologies, it is interesting because it can produce a prototype or a small series of models with extremely complicated geometry. What is drawn in a CAD program very quickly can be in tangible form, saving time and money. The theoretical part of this paper describes additive manufacturing, history and technologies. The emphasis is on FDM technology used in the experimental section. Also, due to the increased use of additive technology, emphasis is also placed on material impact on the ecology. In the experimental part we tested three materials that are commonly used for 3D printing FDM technology. PLA, PETG, and V-generation FACILAN C8 - PLA based blend. The effect of changing the print parameters of the test samples filling on its tensile strength was monitored. At the end of the paper, the test data were analyzed and a conclusion was reached

A Structural Comparison of Spatial Organization in Conventional and Unconventional Military Systems: the Case of the 1954 Algerian Revolution.

We use the Algerian Revolutionary War to do two things of theoretical and substantive importance: to reconsider space as an organizing concept in human behavior, and to direct the attention of military sociology to the study of field operations. Military operational behavior is based on the assumption that space is related to social behavior: military systems control the behavior of the opposition, and of themselves, by controlling the space in which that behavior occurs. This is not just a matter of territoriality, the control of space includes controlling both 'what the space means' and how it is to be exploited. Military systems actively reify operational environments. Most important, the operational environments reified by military systems have organizational consequences. It is these organizational consequences that attract our attention in Algeria in 1954.Ph.D.SociologyUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/159713/1/8402254.pd