323,770 research outputs found
Construction of a tensile tester for light loads
No full textPri razvoju in izdelavi biorazgradljivih polimernih filamentov se pojavljajo problemi s premajhno trdnostjo in krhkostjo materiala. Vse izdelke je potrebno testirati, da se lahko optimira parametre izdelave. Kot podpora izdelavi biorazgradljivih materialov smo v sklopu dela zasnovali in izdelali manjšo napravo za natezni preizkus, ki bo na voljo pri izdelavi filamentov. Za osnovo je bila vzeta kovinska konstrukcija odslužene naprave za merjenje hrapavosti. Izdelali smo sistem za merjenje sile z merilno celico in raztezka s kamero. Izvedli smo natezne preizkuse na filamentih ter natisnjenih epruvetah in preverili ali sistem ustreza standardu ISO 527, ki določa pravila za merjenje nateznih lastnosti plastik.In the development and production of biodegradable polymer filaments, problems arise with insufficient strength and fragility of the material. All products must be tested in order to optimize the manufacturing parameters. To support the production of biodegradable materials, we have designed and produced a small device for tensile testing, which will be available during the production of filaments. The metal structure of roughness measuring device, which was no longer in use, was taken as the basis. We made a system for measuring force with a measuring cell and elongation with a camera. We performed tensile tests on filaments and printed tubes and checked whether the system complies with the ISO 527 standard, which defines the rules for measuring the tensile properties of plastics
Effect of diet on hair cortisol and DHEA concentrations in mouse
No full textObesity and MetS (Metabolic Syndrome) are both linked to persistent long-term hormonal
and metabolic changes. In most of the studies, cortisol (C) and dehydroepiandrosterone
(DHEA) concentrations have been measured in obese and normal-weight subjects,
obtaining heterogeneous results. Plasma, saliva and urine, matrices that represent timepoint
or short-term steroids exposure, were used for these studies. The aim was to study
C, DHEA and C/DHEA ratio of mice pups in the hair, matrix capable of providing
cumulative hormonal exposure. Sixty C57Bl/6 mice pups (30 males and 30 females)
were housed in a temperature-controlled environment (22±2°C) and on a 12h light/dark
schedule, under ad-libitum access to food and water for 16 weeks (welfare: Italian Law
Decree 116-92 and EC Directive 86-609-EEC). Control and experimental diets were
offered immediately after weaning (3 weeks old pups), for 16 weeks. Four experimental
checkpoints were established (T1: 4 weeks, T2: 8 weeks, T3: 12 weeks and T4: 16 weeks
of diet). T3 and T4 showed the hormonal concentrations of pubertal animals. Twentyseven
pups (13 females and 14 males) were randomly group-housed in cages (6 for T1, 5
for T2, 6 for T3, 10 for T4) and assigned to control diet (CTRL: D12328, Research Diets,
New Brunswick, NJ). 33 pups (17 females and 16 males) were randomly group-housed in
cages (5 for T1, 6 for T2 and T3, 16 for T4) and assigned to the HFHC diet (HFHC: D12331, Research Diets, New Brunswick, NJ - plus 42g/L fructose/sucrose in drinking
water). At each experimental checkpoint, all the animals of one cage for each
experimental group were suppressed. Hair strands were carefully cut with scissors as
close as possible to the skin from the back of the mice, paying attention to not to wound
the animals. Hair was stored in an envelope at RT in a dry room until use. C and DHEA
hair concentrations was measured by a solid-phase microtiter RIA assay (Peric et al., 2016 adapted in the mouse). Only at 8 weeks the HFHC group showed significantly
higher C concentrations than the CTRL group (1.56±0.06 vs 1.92±0.130 pg/mgP<0.05).
DHEA concentrations were significantly reduced in the HFHC group than the CTRL
group at 4 (114.64±13.93 vs 69.08±5.33 pg/mgP<0.05), 8 (71.67±7.08 vs 50.38±4.74
pg/mgP<0.05), 12 (73.27±8.29 vs 41.59±1.60 pg/mgP<0.01) and 16 weeks
(65.26±3.35 vs 55.05±1.84 pg/mgP<0.05). The C/DHEA ratio was significantly
increased in the HFHC than the CTRL group, at 8 (0.023±0.002 vs 0.040±0.005P<0.01),
12 (0.024±0.003 vs 0.036±0.004P<0.05) and 16 weeks (0.019±0.001 vs 0.025±0.002P<0.01). The gender effect was not significant. Taking into account the lag time required
for the hair emersion from the skin (about 1 week), the significant stimulation of the C at
8 weeks in the HFHC group refers to its chronic elevation from 5 to 7 weeks of treatment
when the animals were not pubertal. Conversely, DHEA shows a chronic reduction in
obese mice leading to consider an independent adrenal regulation of C and DHEA, both
stimulated by ACTH.
Research was supported by the Project CBM (MIUR DM60643).
Peric et al. 2016 J Appl Anim Welf Sci 18:1-8
An analysis of purchase resources and an upgrade of decision making process using a multi-criteria decision model in Ebm-papst company.
No full textV magistrskem delu obravnavamo analizo nabavnih virov in nadgrajujemo proces odločanja z uporabo večkriterijskega odločitvenega modela. V izbranem podjetju Ebm-papst so se zaradi vedno večje konkurenčnosti in v želji kreiranja nabavnih prihrankov lotili iskanja novih nabavnih virov na področju jugovzhodne Evrope za blagovno skupino aluminijastih odlitkov. Z analizo smo ugotovili, da imajo v podjetju definiran zgolj proces ocenjevanja obstoječih dobaviteljev, zato smo se lotili nadgradnje procesa izbora novega dobavitelja. V prvem koraku smo na podlagi pregleda strokovne literature empirično proučili ter izpostavili najpomembnejše kriterije pri izboru novega dobavitelja. Ti so bili izbrani na podlagi matrike SPM in PPM. Za pridobivanje podatkov smo uporabili kvantitativno in kvalitativno znanstvenoraziskovalno metodo. Analizo smo opravili na podlagi izpolnjenih vprašalnikov ter ocenjevanj, opravljenih med obiskom pri dobaviteljih. Opravljen pa je bil tudi nestrukturiran globinski intervju s petimi strokovnjaki, nabavniki aluminijastih odlitkov. Zaradi kompleksnosti smo problem odločanja razdelili na dve stopnji. V prvi stopnji smo definirali izločitvene kriterije in s t testom preverili hipotezi. Pripravili smo odločitveni model z uporabo metode DEX ter definirali štiri strategije pristopa do novih dobaviteljev pri vključevanju teh v panel dobaviteljev, kar bo imelo praktične implikacije za izbrano podjetje in širše. Opravili smo vrednotenje dvanajstih dobaviteljev ter na podlagi praktičnih testov ocenili razviti model ter predlagali tudi izboljšave, vezane na model. V zaključku smo podali predloge izboljšav za celoten proces izbora novih dobaviteljev v izbranem podjetju.In the master\u27s thesis, we discuss the analysis of procurement sources and we upgrade the decision-making process using a multi-criteria decision model. Due to increasing competitiveness and the desire to make purchasing savings, the selected company Ebm-papst started searching for new purchasing sources in the area of Southeast Europe for the aluminum castings product group. With the analysis, we found that the company has only defined the process of evaluating existing suppliers, so we proceeded to upgrade the selection process of a new supplier. In the first step, based on a review of the professional literature, we empirically examine and highlight the most important criteria in selecting a new supplier. These were selected based on the SPM and PPM matrix. For obtaining data, quantitative and qualitative research methods were used. The analysis was performed on the basis of completed questionnaires and assessments performed during a visit to suppliers. An unstructured in-depth interview was also conducted with five experts, purchasers of aluminum castings. Due to the complexity, we divided the decision-making problem into two stages. In the first stage, we defined the exclusion criteria and tested the hypotheses with a t-test. We prepared a decision model using the DEX method and defined four strategies of approach to new suppliers in the inclusion of the latter in the panel of the suppliers, which will have practical implications for the selected company and more. We evaluated twelve suppliers and, based on practical tests, we evaluated the developed model and we also proposed model-related improvements. In conclusion, we made suggestions for improvements for the entire process of selecting new suppliers in the selected company
Production of filament from polyvinyl alcohol and microcrystalline cellulose
No full textUporaba aditivnih tehnologij je v porastu. Ena izmed teh je tudi tehnologija ciljnega nalaganja. 3D tiskalniki, ki delujejo po principu ciljnega nalaganja, uporabljajo filamente iz različnih polimerov. Zaradi svetovnih razmer so v ospredju raziskav biorazgradljivi materiali. V nalogi obravnavamo izdelavo okolju prijaznega filamenta za 3D tiskalnik iz polivinil alkohola z dodatkom mikrokristalne celuloze za izboljšanje mehanskih lastnosti. Izdelali smo testne granule iz polivinil alkohola in mikrokristalne celuloze v različnih koncentracijah. S postopkom ekstruzije smo granule pretvorili v filamente z različnimi vsebnostmi celuloze. Na vzorcih filamentov smo opravili optične analize in dimenzijske meritve. Ugotovili smo, da so filamenti v večini homogeni in dobro strukturirani. Vendar so za uporabo filamenta na 3D tiskalniku še potrebne dodelave.The use of additive manufacturing technologies is on the rise. One of these is also Fused Filament Fabrication. 3D printers, that use FFF technology, use polymer filaments. Due to the global situation, biodegradable materials are at the forefront of research. The aim of the thesis is to make an environmentally friendly filament for 3D printers from polyvinyl alcohol with the addition of microcrystalline cellulose to improve mechanical properties. Test granules from polyvinyl alcohol and microcrystalline cellulose in different concentrations were transformed into filaments with different cellulose contents using extrusion process. Optical analyses and dimensional measurements were carried out on filament samples. We found out that filaments are mostly homogenous and well structured. But for use on a 3D printer out methodology needs some finishing
Sexual Hormone Fluctuation in Chinchillas.
No full textThe data about chinchilla (Chinchilla laniger) reproduction are limited and in some cases discordant. The aim of this study was to monitor the sexual hormone fluctuation by fecal progesterone level and colpocytology analysis by vaginal smears in order to evaluate the different phases of the oestrus cycle. Twenty-four non pregnant chinchillas aged from 1 to 4 years old and subdivided in three groups were monitored. In contrast with findings reported in other study, the high values of progesterone recorded in autumn suggested the presence of a ciclicity also in this period. The data indicate that chinchilla presents a continuous cycle
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
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