Quality Comparison of Three Fused Deposition Modeling (FDM) Printers at Different Cost Levels

The purpose of this study was to better define how quality in terms of surface quality, dimensional accuracy, consistency/repeatability, and total build time vary based upon 3D printers in different cost levels. One FDM printer was chosen at cost levels of entry level, intermediate level, and commercial level. A test block with various raised and recessed geometrical shapes was printed on each printer to analyze average surface roughness, dimensional accuracy, consistency/repeatability and total print time. When comparing the results, the most significant advantage with increased printer cost was the decrease in total print time. The commercial level printer, the Fortus 450, had a decrease in total build time to less than a fifth of the intermediate level printer, the 3D Platform printer. The 3D Platform decreased build time by nearly half as compared to the entry level printer, the MakerBotz 18s. Dimensional accuracy did not vary significantly between the printers, but the Fortus 450 did show the best consistency and repeatability. As far as surface roughness, the least rough measurements were taken on the test block side in the direction of increased layer height, while the measurements taken on the test block bottom/top in the direction parallel to the printer build plate, were roughest. When comparing surface roughness by printer there was not significant difference, but the Fortus 450 visually showed more consistent surface quality with minimal or no gap in the filament beads and also showed very consistent surface roughness measurements in three directions. Based upon the results when choosing a 3D printer as the cost increases, the driving factors appear to be total print time and consistency in accuracy and surface quality but in general, the best printer to choose is based upon how cost, surface quality, dimensional accuracy, consistency/repeatability, and total print time are ranked based upon the project

Materials for education in biochemistry at secondary school - smooth and skeletal muscle

Modern society gives humanity many guarantees and many benefits. Although one of the biggest problems nowadays is that most of us spend much time sitting at computers or TVs. Another problem is the excess of an unsuitable diet, which threatens our health. This lifestyle harms our health and contributes to the outbreak of diseases in civilization, among other things. These diseases are the leading cause of death in civilized countries. It is no wonder that some parts of society are already aware of this issue, and its goal is to motivate people to spend their free time actively, for example, with regular exercise or sports. It is necessary to emphasize the relationship between health problems and a sedentary lifestyle by integrating such topics into teaching grammar school subjects. We could combine chemistry, biology and physical education with helping students find new ways to understand the importance of physical activity. The work focuses on skeletal and smooth muscle because it is closely related to movement and is also the subject of teaching in secondary schools. However, in the current teaching materials, this topic is conceived rather descriptively, with students learning many medical terms, and the interpretation of the mechanism of muscle activity is limited to skeletal muscles. This...Moderní spole nost dává lov ku adu jistot a výhod, avšak jedním z jejích vážných problém je i to že v tšina z nás tráví nep irozen dlouhou dobu sedavým zp sobem u po íta , televizí apod., což má spolu s nadbytkem nevhodné stravy na naše zdravý velmi neblahý vliv a p ispívá mimo jiné k "epidemii" civiliza ních chorob, které obsazují první p í ky v p í inách úmrtí civilizovaného lov ka. Není divu, že ást spole nosti, která si toto uv domuje, si klade za cíl, aby lidi trávili sv j volný as aktivn , tedy pohybem a sportem. Aby se situace zlepšila, je t eba tuto problematiku více zd raz ovat a nezapomínat ji za le ovat i do výuky st edoškolských p edm t , pomoci žák m hledat nové cesty k pochopení významu podstaty pohybu a k tomu je vhodné využít a propojit chemií, biologií a t lesnou výchovu. Problematika kosterní a hladké svaloviny je na st ední škole p edm tem výuky biologie lov ka, zde je však výuka tématu pojatá spíše popisnou formou, p i níž se žáci u í spoust odborných termín (vesm s léka ských pojm ) a samotný výklad mechanismu svalové innosti se omezuje jen na popis kosterní (p í n pruhované) svaloviny. K podpo e výuku této problematiky na st edních školách gymnaziálního typu se snaží p isp t tato bakalá ská práce. Sou ástí práce je rozbor vybraných st edoškolských u ebnic chemie a biologie,...Department of Chemistry EducationKatedra učitelství a didaktiky chemiePřírodovědecká fakultaFaculty of Scienc

Analysis of the selected swimmer's breaststroke technique

Title: Analysis of the selected swimmer's breaststroke technique Complained by: Petr Honomichl Supervisor: Mgr. Aleš Zenáhlík Objectives: The aim of the study was to analyse the breaststroke swimming technique of a selected swimmer. Within the framework of the performed analysis, we focus on the control of technical deficiencies in the movement of individual body segments with a link to the overall movement coordination, which affects the resulting efficiency of movement in the aquatic environment. Methods: From the video footage, an analysis of the breaststroke swimming technique was performed. The data collection was carried out at the swimming pool of the swimming club SK Motorlet Praha. During filming, videos of the swimmer from the side above the water, from the side and the front under the water were taken. The video material was taken with a camera borrowed from the fund of the Department of Swimming, Aquatic and Technical Sports, FTVS UK. The video footage was processed using Kinovea software. Images with technical flaws were selected. Based on the technical deficiencies found, appropriate corrective exercises were suggested to improve the given deficiencies in technical execution. Results: On the basis of the analysis of the breaststroke swimming technique after the first shooting,...Název: Analýza techniky plaveckého způsobu prsa vybraného plavce Zpracoval: Petr Honomichl Vedoucí: Mgr. Aleš Zenáhlík Cíle práce: Cílem práce bylo provést analýzu plavecké techniky plaveckého způsobu prsa u vybraného plavce. V rámci provedené analýzy se zaměřujeme na kontrolu technických nedostatků v pohybu jednotlivých tělesných segmentů s vazbou na celkovou pohybovou souhru, která ovlivňuje výslednou efektivitu pohybu ve vodním prostředí. Metodika práce: Z pořízených videomateriálů byla provedena analýza techniky plaveckého způsobu prsa. Sběr dat byl realizován na bazénu plaveckého oddílu SK Motorlet Praha. Při natáčení byly pořízeny videa plavce z boku nad hladinou, z boku a čela pod hladinou. Videomateriál by pořízen kamerou GoPro HERO 10 zapůjčenou z fondu Katedry plaveckých, vodních a technických sportů FTVS UK. Pořízený videomateriál byl zpracován pomocí softwaru Kinovea. Byly vybrány snímky, na kterých se vyskytují nedostatky v technickém provedení. Na základě nalezených technických nedostatku byla navržena vhodná korekční cvičení pro zlepšení daných nedostatků v technickém provedení. Výsledky práce: Na základě analýzy techniky plaveckého způsobu prsa po prvním natáčení byla navržena korekční cvičení, která si kladla za cíl eliminovat nalezené technické nedostatky. Komparací s druhým...Katedra plaveckých, vodních a technických sportůDepartment of Swimming, Water and Technical SportsFaculty of Physical Education and SportFakulta tělesné výchovy a sport

Satellite data validation: a parametrization of the natural variability of atmospheric mixing ratios

High-resolution model data are used to estimate the statistically typical mixing ratio variabilities of trace species as a function of distance and time separation. These estimates can be used to explain the fact that some of the differences between observations made with different observing systems are due to the less-than-perfect co-location of the measurements. The variability function is approximated by a two-parameter regression function, and lookup tables of the natural variability values as a function of distance separation and time separation are provided. In addition, a reparametrization of the variability values as a function of latitudinal gradients is proposed, and the seasonal independence of the linear approximation of such a function is demonstrated

Testing a scalable web and smartphone based intervention to improve depression, anxiety, and resilience: A randomized controlled trial

Psychological interventions targeting wellbeing can reliably increase wellbeing and decrease depressive symptoms. However, only a handful of studies have implemented wellbeing interventions online, and those studies have largely done so in a way that prioritizes experimental control over realism and scalability. We sought to take existing wellbeing interventions with established efficacy and to evaluate their impact when translated into a format that is publicly accessible, scalable, and designed with the goal of engaging users. Participants in this fully online trial were first-time registrants of the Happify platform, a fully automated web and mobile wellbeing intervention grounded in positive psychology, cognitive-behavioral therapy, and mindfulness-based stress reduction, which has offered wellbeing programs to over 3 million registrants to date. Consenting participants were randomly assigned to access the full Happify platform or a psychoeducation comparison condition and further categorized by their usage during the study: recommended usage (a minimum of 2-3 activities per week) or low usage (usage less than the recommended level). Participants were assessed on depressive symptoms, anxiety symptoms, and a composite measure of resilience at baseline and 8 weeks later. Participants who used Happify at the recommended level reported fewer depressive and anxiety symptoms and greater resilience after 8 weeks than participants who used Happify at a low level or participants who used the psychoeducation condition at any level. The Happify group also experienced greater rates of reduction in depression and anxiety symptom severity category, and had a greater net benefit (% users who improved minus % users who deteriorated), compared to the other groups. The results of this study suggest a successful first attempt at implementing and scaling a comprehensive package of lab-tested wellbeing interventions without losing efficacy

Didymosphenia geminata: Algal blooms in oligotrophic streams and rivers

In recent decades, the diatom Didymosphenia geminata has emerged as nuisance species in river systems around the world. This periphytic alga forms large “blooms” in temperate streams, presenting a counterintuitive result: the blooms occur primarily in oligotrophic streams and rivers, where phosphorus (P) availability typically limits primary production. The goal of this study is to examine how high algal biomass is formed under low P conditions. We reveal a biogeochemical process by which D. geminata mats concentrate P from flowing waters. First, the mucopolysaccaride stalks of D. geminata adsorb both iron (Fe) and P. Second, enzymatic and bacterial processes interact with Fe to increase the biological availability of P. We propose that a positive feedback between total stalk biomass and high growth rate is created, which results in abundant P for cell division. The affinity of stalks for Fe in association with iron-phosphorus biogeochemistry suggest a resolution to the paradox of algal blooms in oliogotrophic streams and rivers

Observations of ozone-poor air in the tropical tropopause layer

Ozonesondes reaching the tropical tropopause layer (TTL) over the west Pacific have occasionally measured layers of very low ozone concentrations - less than 15 ppbv - raising the question of how prevalent such layers are and how they are formed. In this paper, we examine aircraft measurements from the Airborne Tropical Tropopause Experiment (ATTREX), the Coordinated Airborne Studies in the Tropics (CAST) and the Convective Transport of Active Species in the Tropics (CONTRAST) experiment campaigns based in Guam in January-March 2014 for evidence of very low ozone concentrations and their relation to deep convection. The study builds on results from the ozonesonde campaign conducted from Manus Island, Papua New Guinea, as part of CAST, where ozone concentrations as low as 12 ppbv were observed between 100 and 150 hPa downwind of a deep convective complex. TTL measurements from the Global Hawk unmanned aircraft show a marked contrast between the hemispheres, with mean ozone concentrations in profiles in the Southern Hemisphere between 100 and 150 hPa of between 10.7 and 15.2 ppbv. By contrast, the mean ozone concentrations in profiles in the Northern Hemisphere were always above 15.4 ppbv and normally above 20 ppbv at these altitudes. The CAST and CONTRAST aircraft sampled the atmosphere between the surface and 120 hPa, finding very low ozone concentrations only between the surface and 700 hPa; mixing ratios as low as 7 ppbv were regularly measured in the boundary layer, whereas in the free troposphere above 200 hPa concentrations were generally well in excess of 15 ppbv. These results are consistent with uplift of almost-unmixed boundary-layer air to the TTL in deep convection. An interhemispheric difference was found in the TTL ozone concentrations, with values < 15 ppbv measured extensively in the Southern Hemisphere but seldom in the Northern Hemisphere. This is consistent with a similar contrast in the low-level ozone between the two hemispheres found by previous measurement campaigns. Further evidence of a boundary-layer origin for the uplifted air is provided by the anticorrelation between ozone and halogenated hydrocarbons of marine origin observed by the three aircraft

Die Welt erlesen: Leseförderung in Chemnitz, Glauchau, Hohenstein-Ernstthal und Leipzig

37 % aller Kinder wird niemals ein Buch vorgelesen, weder im Elternhaus noch im Kindergarten oder in der Schule. Dies geht aus einer aktuellen Umfrage der Stiftung Lesen hervor. Dabei ist das Vorlesen die Mutter des Lesens, wie Goethe schon wusste

Bimodal distribution of free tropospheric ozone over the tropical western Pacific revealed by airborne observations

A recent airborne field campaign over the remote western Pacific obtained the first intensive in situ ozone sampling over the warm pool region from oceanic surface to 15-km altitude (near 360-K potential temperature level). The new data set quantifies ozone in the tropical tropopause layer under significant influence of convective outflow. The analysis further reveals a bimodal distribution of free tropospheric ozone mixing ratio. A primary mode, narrowly distributed around 20-ppbv, dominates the troposphere from the surface to 15-km. A secondary mode, broadly distributed with a 60-ppbv modal value, is prominent between 3 and 8-km (320-K to 340-K potential temperature levels). The latter mode occurs as persistent layers of ozone-rich drier air and is characterized by relative humidity under 45%. Possible controlling mechanisms are discussed. These findings provide new insight into the physical interpretation of the >S>-shaped mean ozone profiles in the tropics.Peer Reviewe