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

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

New Materials to Support the Teaching of Biochemistry in Secondary Schools - Carbohydrates and Other Selected Nutrients and Their Role in Nutrition and Human Health

Humanity has undergone many changes throughout its history, with one of the most significant being the change in our diet, particularly in the composition and quantity of products consumed. An increase in the amount of carbohydrate-dominated foods has been typical, which, combined with a lack of exercise, has led to the development of obesity and related to civilisation diseases. Affected individuals also experience a significant reduction in life expectancy and quality of life. In addition, as the number of individuals suffering from civilisation disease increases, so do the costs of healthcare. The state and some sections of society are aware of these dire consequences and are trying to educate people on these issues through various support and education programmes. However, these efforts are counteracted by the policies of industrial companies whose commercial interest is to sell highly processed food. They provide us with food products that usually have an appealing taste but a completely inappropriate nutritional composition. This may be a major factor contributing to the unhealthy eating habits of a significant proportion of the population. A person who has received good education in the field and who understands the basic processes of the human body can make right decisions about his or her...Lidstvo v průběhu své historie prošlo řadou změn, přičemž mezi nejvýznamnější patří změna našeho stravování, především co se týče složení a množství konzumovaných produktů. Typický je nárůst množství potravin s převahou sacharidů, což v kombinaci s nedostatkem pohybu vede k rozvoji obezity a souvisejících civilizačních chorob. U postižených jedinců se také významně snižuje délka a kvalita života. Navíc s rostoucím počtem jedinců trpících civilizačními chorobami narůstají i náklady na zdravotní péči. Stát a některé části společnosti si tyto neblahé důsledky uvědomují a snaží se lidem poskytovat vzdělání v této problematice prostřednictvím různých podpůrných a vzdělávacích programů. Avšak proti tomuto úsilí působí politika průmyslových společností, jejichž komerčním zájmem je prodej vysoce průmyslově zpracovaných potravin. Ty nám podbízejí potraviny obvykle s lákavou chutí, ale se zcela nevhodným nutričním složením. To může být hlavním faktorem přispívajícím k nevhodným stravovacím návykům značné části populace. Člověk, kterému se v dané oblasti dostalo kvalitního vzdělání, a který rozumí základním procesům probíhajícím v lidském těle, se může o svém stravování správně rozhodovat sám a nepodlehne snadno manipulacím či reklamním sloganům. Proto je důležité předávání porozumění a pochopení vztahu mezi...Department of Chemistry EducationKatedra učitelství a didaktiky chemieFaculty of SciencePřírodovědecká fakult

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

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

The National Cybersecurity Teaching Coalition: Expanding Cybersecurity Education Opportunities

The increasing prevalence of cybersecurity threats and the shortage of qualified professionals necessitate innovative solutions for cybersecurity education at all levels. Despite the expansion of post-secondary cybersecurity programs, employer dissatisfaction with graduates and a lack of standardized introductory curricula highlights the need for structured secondary education pathways. The National Cybersecurity Teaching Coalition (NCTC) and its National Cybersecurity Teaching Academy (NCTA) address this gap by equipping high school educators with the necessary knowledge and credentials to teach cybersecurity effectively. NCTA offers an 18-credit cybersecurity graduate certificate program to ensure teachers are competent and confident to develop and teach cybersecurity curriculum with consistent learning outcomes across institutions. This paper examines the state of the cybersecurity workforce, the development of the NCTA program and curriculum, and the evolution of the program. Additionally, this paper evaluates the NCTA program based on external evaluation results, emphasizing the importance of qualified educators in fostering cybersecurity awareness and career readiness. Future initiatives focus on professionalizing cybersecurity, developing state-level licensing and endorsements, and reinforcing the role of educators in securing the nation against evolving cyber threats

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

An Observationally Constrained Evaluation of the Oxidative Capacity in the Tropical Western Pacific Troposphere

Hydroxyl radical (OH) is the main daytime oxidant in the troposphere and determines the atmospheric lifetimes of many compounds. We use aircraft measurements of O3, H2O, NO, and other species from the Convective Transport of Active Species in the Tropics (CONTRAST) field campaign, which occurred in the tropical western Pacific (TWP) during January–February 2014, to constrain a photochemical box model and estimate concentrations of OH throughout the troposphere. We find that tropospheric column OH (OHCOL) inferred from CONTRAST observations is 12 to 40% higher than found in chemical transport models (CTMs), including CAM-chem-SD run with 2014 meteorology as well as eight models that participated in POLMIP (2008 meteorology). Part of this discrepancy is due to a clear-sky sampling bias that affects CONTRAST observations; accounting for this bias and also for a small difference in chemical mechanism results in our empirically based value of OHCOL being 0 to 20% larger than found within global models. While these global models simulate observed O3 reasonably well, they underestimate NOx (NO + NO2) by a factor of two, resulting in OHCOL ~30% lower than box model simulations constrained by observed NO. Underestimations by CTMs of observed CH3CHO throughout the troposphere and of HCHO in the upper troposphere further contribute to differences between our constrained estimates of OH and those calculated by CTMs. Finally, our calculations do not support the prior suggestion of the existence of a tropospheric OH minimum in the TWP, because during January–February 2014 observed levels of O3 and NO were considerably larger than previously reported values in the TWP

The convective transport of active species in the tropics (Contrast) experiment

The Convective Transport of Active Species in the Tropics (CONTRAST) experiment was conducted from Guam (13.5degN, 144.8degE) during January-February 2014. Using the NSF/NCAR Gulfstream V research aircraft, the experiment investigated the photochemical environment over the tropical western Pacific (TWP) warm pool, a region of massive deep convection and the major pathway for air to enter the stratosphere during Northern Hemisphere (NH) winter. The new observations provide a wealth of information for quantifying the influence of convection on the vertical distributions of active species. The airborne in situ measurements up to 15-km altitude fill a significant gap by characterizing the abundance and altitude variation of a wide suite of trace gases. These measurements, together with observations of dynamical and microphysical parameters, provide significant new data for constraining and evaluating global chemistry climate models. Measurements include precursor and product gas species of reactive halogen compounds that impact ozone in the upper troposphere/lower stratosphere. High-accuracy, in situ measurements of ozone obtained during CONTRAST quantify ozone concentration profiles in the upper troposphere, where previous observations from balloon-borne ozonesondes were often near or below the limit of detection. CONTRAST was one of the three coordinated experiments to observe the TWP during January-February 2014. Together, CONTRAST, Airborne Tropical Tropopause Experiment (ATTREX), and Coordinated Airborne Studies in the Tropics (CAST), using complementary capabilities of the three aircraft platforms as well as ground-based instrumentation, provide a comprehensive quantification of the regional distribution and vertical structure of natural and pollutant trace gases in the TWP during NH winter, from the oceanic boundary to the lower stratosphere