Quick-cast: A method for fast and precise scalable production of fluid-driven elastomeric soft actuators

Fluid-driven elastomeric actuators (FEAs) are among the most popular actuators in the emerging field of soft robotics. Intrinsically compliant, with continuum of motion, large strokes, little friction, and high power-to-weight ratio, they are very similar to biological muscles, and have enabled new applications in automation, architecture, medicine, and human-robot interaction. To foster future applications of FEAs, in this paper we present a new manufacturing method for fast and precise scalable production of complex FEAs of high quality (leak-free, single-body form, with <0.2 mm precision). The method is based on 3d moulding and supports elastomers with a wide range of viscosity, pot life, and Young's modulus. We developed this process for two different settings: one in laboratory conditions for fast prototyping with 3d printed moulds and using multi-component liquid elastomers, and the other process in an industrial setting with 3d moulds micromachined in metal and applying compression moulding. We demonstrate these methods in fabrication of up to several tens of two-axis, three-chambered soft actuators, with two types of chamber walls: cylindrical and corrugated. The actuators are then applied as motion drivers in kinetic photovoltaic building envelopes

Kritischer Vergleich der literaturtheoretischen Methodik

Die Frage nach der richtigen Interpretation eines literarischen Werks und der damit verbundenen Anwendung einer bestimmten literaturtheoretischen Methodik sorgt nicht nur unter Literaturwissenschaftlern oft für Diskussionen. Das Werk von Franz Kafka hat dabei eine besondere Stellung, da seine Texte Ansatzpunkte und Interpretationsspielraum für so gut wie jede Literaturtheorie liefern. Aus diesem Grund wurde für diese Arbeit über einen „kritischen Vergleich der literaturtheoretischen Methodik“ eines von jenen Werken Kafkas ausgewählt, die beispielhaft für diese vielfältigen Interpretationsmöglichkeiten sind. „Das Urteil“ ist eine Geschichte, die derart viel Spielraum für unterschiedliche Methoden anbietet, dass bereits unzählige Analysen verschiedener literaturwissenschaftlicher Disziplinen zu ihr vorliegen. Um diese Vielfalt zu verdeutlichen, wurde als Grundlage für die vorliegende Arbeit „Kafkas »Urteil« und die Literaturtheorie – Zehn Modellanalysen“ ausgewählt. Nach ein paar allgemeinen Überlegungen im ersten Drittel der Arbeit werden im zweiten Teil einige dieser Modellanalysen untersucht und auch miteinander in Beziehung gebracht. Die Beispiele für angewandte Hermeneutik, Strukturalismus, Psychoanalyse und Dekonstruktion weisen sehr unterschiedliche Herangehensweisen an literarische Werke auf. Erwartungsgemäß führen diese verschiedenen Methoden oft zu widersprüchlichen Ergebnissen. Dennoch gibt es bei einem Vergleich der wissenschaftlichen Methoden auch erstaunliche Parallelen und Gemeinsamkeiten bei Anwendung Ergebnissen divergenter theoretischer Modelle. Dies wird anhand der ausgewählten Beispiele veranschaulicht. Konzentrieren sich die Methoden für ihre Analysen auf unterschiedliche Eigenschaften des Textes, so bewegen sie sich trotzdem stets im selben Bereich. Ausgangspunkte all dieser Modelle sind und bleiben der zu untersuchende Text und auf Vernunft und aktuellem Wissensstand basierende Interpretationen einzelner Eigenschaften des Textes. Das rührt daher, dass sämtliche literaturwissenschaftlichen Modelle auf Basis und als Ergänzung und Erweiterung der Hermeneutik entstanden sind, indem Methoden anderer philologischer Disziplinen herangezogen und für die Literaturwissenschaft adaptiert wurden. Diese fremde Herkunft vieler theoretischer Modelle hat zu einer Fokusverschiebung in deren Anwendung geführt. Bei vielen Analysen geht es weniger darum, durch die Anwendung der für das Untersuchungsobjekt passenden Methode zu eindeutigen und nachvollziehbaren Ergebnissen zu kommen. Literaturwissenschaftler konzentrieren sich oftmals mehr darauf zu veranschaulichen, dass ihre Wahl der Untersuchungsmethode die richtige ist. Dabei geht es, wie bereits erwähnt, weniger um neue Erkenntnisse, sondern eher darum, die Möglichkeit der Anwendung einer Methode zu beweisen und damit diese Entscheidung und auch die Existenz der philologischen Denkweise als literaturwissenschaftliches Instrument zu legitimieren. Mit der Frage nach einer richtigen oder gar universell anwendbaren Theorie hat dies jedoch denkbar wenig zu tun. Um für ein Werk die „richtige“ Interpretationsmethode zu finden, ist es notwendig, unvoreingenommen an einen Text heranzugehen. Durch eine hermeneutische Untersuchung, die nach und nach durch spezifischere Modelle erweitert wird, können im Ausschlussverfahren fruchtbare und unfruchtbare Methoden identifiziert werden. So ist es möglich, im Idealfall das ganze Bedeutungsspektrum des untersuchten Textes aufzuschlüsseln. Man könnte also sagen, dass es nicht darum geht, die „richtige“ Methode, sondern die richtige Kombination aus den zur Verfügung stehenden Denkansätzen zu finden

Predictors of Engagement in a Parenting Intervention Designed to Prevent Child Maltreatment

Objective: The objectives of this analysis were to: 1) assess the impact of sociodemographic factors, and perceived costs and benefits on engagement in a parenting program designed to prevent child maltreatment, 2) determine if perceived costs and benefits mediated the association between sociodemographic factors and engagement, and 3) assess whether or not race/ethnicity moderated the relationship between sociodemographic factors, perceived costs and benefits, and engagement.Methods: Perceived costs and benefits of the intervention were assessed from parents providing self-reports, including satisfaction/ usefulness of the program (benefits), and time/difficulty associated with the program (costs). Engagement was defined as attendance at both the mid-point and then the number of visits attended throughout the remainder of the intervention. To investigate the direct and indirect effects (through perceived costs and benefits) of parental sociodemographic factors (education, age, gender, number of children, household income) on program engagement, data were analyzed with structural equation modeling (SEM). To assess the potential moderating effect of race/ethnicity, separate models were tested for White and African-American parents.Results: Perceived benefits positively impacted attendance for both White (n=227) and African-American (n=141) parents, whereas perceived costs negatively influenced attendance only for White parents. Parent education and age directly impacted attendance for White parents, but no sociodemographic factor directly impacted attendance for African-American parents. The indirect impact of sociodemographic characteristics on attendance through perceived costs and perceived benefits differed by race/ethnicity.Conclusions: Results suggest that White parents participate in a parenting program designed to prevent child maltreatment differently based upon their perceived benefits and costs of the program, and based on benefits only for African-American parents. Parental perception of costs and/or benefits of a program may threaten the effectiveness of interventions to prevent child maltreatment for certain racial/ethnic groups, as it keeps them from fully engaging in empirically validated programs. Different methods may be required to retain participation in violence prevention programs depending upon race/ethnicity

Forskningens rolle i forbedringer af matematikundervisning

Artiklen bringes med tilladelse fra Springer Science+Business Media. Den er udgivet iEducational Studies in Mathematics, vol. 2, nr. 2/3, Addresses of the First InternationalCongress on Mathematical Education (december 1969), s. 232-244. Udgivet af: SpringerStable, www.jstor.org/stable/3482078

Mother-Infant Interactions: How Mothers of Hearing-Impaired Infants Interact With Their Babies Through Touch

Since the majority of their caregivers are hearing and use spoken language, most hearing-impaired infants (HII) are faced with a different language-learning problem than their age-matched hearing (AM) peers. A hearing mismatch occurs when a caregiver and her child receive variant levels of auditory input due to their different hearing abilities. Given that HII do not treat speech as a primary mode of communication, it is possible that their caregivers may exploit non-speech modalities when interacting with their infants—similar to deaf parents of deaf infants. However, due to mismatched hearing statuses, parents of HII may have a difficulty in utilizing the modality that best corresponds with their infants’ abilities. It is imperative to understand how hearing caregivers interact with their HII in order to explore the most relevant method of communication to enhance infants’ language learning. We video- and audio-recorded play interactions between mothers of HII (4 cochlear implant users; 2 hearing aid users) and mothers of AM peers (6 hearing). Mothers were given three toys and asked to play with their child, “as they would at home.” We measured pitch, duration, and intensity in their production of the names of the toys. We also measured the number and types of touches mothers produced. Results revealed that mothers of HII and AM peers had very similar measures for pitch, duration, and intensity. However, the number and type of touches were distinct: HII were touched more than three times more frequently than AM peers. Thus, findings from this study suggest that mothers of HII may exploit non-speech modalities when they have a hearing mismatch with their child

New Media and Online Mathematics Learning for Teachers

In this chapter we offer a case study of an online Mathematics for Teachers course through the lens of four affordances of new media: democratization, multimodality, collaboration and performance. Mathematics, perhaps more so than other school subjects, has traditionally been a subject that people do not talk about outside of classroom settings. However, we demonstrate through the case of the Mathematics for Teachers course that this does not have to be the case. Mathematics, even mathematics that traditionally has been seen as abstract or inaccessible, can be talked about in ways that can engage not only adults but also young children. The affordances of new media can help us rethink and disrupt our existing views of mathematics (for teachers and for students) and of how it might be taught and learned, by (1) blurring teacher/student distinctions and crossing hierarchical curriculum boundaries; (2) communicating mathematics in multimodal ways; (3) seeing mathematics as a collaborative enterprise; and (4) helping us learn how to relate good math stories to classmates and family when asked “What did you do in math today?

Sleep Is Compromised in −12° Head Down Tilt Position

Recent studies are elucidating the interrelation between sleep, cranial perfusion, and cerebrospinal fluid (CSF) circulation. Head down tilt (HDT) as a simulation of microgravity reduces cranial perfusion. Therefore, our aim was to assess whether HDT is affecting sleep (clinicaltrials.gov; identifier NCT 02976168). 11 male subjects were recruited for a cross-over designed study. Each subject participated in two campaigns each comprising 3 days and 2 nights. Intervention started on the second campaign day and consisted of maintenance of horizontal position or −12° HDT for 21 h. Ultrasound measurements were performed before, at the beginning and the end of intervention. Polysomnographic measurements were assessed in the second night which was either spent in horizontal posture or at −12° HDT. Endpoints were sleep efficiency, sleep onset latency, number of sleep state changes and arousals, percentages of N3, REM, light sleep stages and subjective sleep parameters. N3 and REM sleep reduced by 25.6 and 19.1 min, respectively (P = 0.002, g = -0.898; P = 0.035, g = -0.634) during −12° HDT. Light sleep (N1/2) increased by 33.0 min at −12° HDT (P = 0.002, g = 1.078). On a scale from 1 to 9 subjective sleep quality deteriorated by 1.3 points during −12° HDT (P = 0.047, g = -0.968). Ultrasonic measurement of the venous system showed a significant increase of the minimum (P = 0.009, P &lt; 0.001) and maximum (P = 0.004, P = 0.002) cross-sectional area of the internal jugular vein at −12° HDT. The minimum cross-sectional area of the external jugular vein differed significantly between conditions over time (P = 0.001) whereas frontal skin tissue thickness was not significantly different between conditions (P = 0.077, P = 0.811). Data suggests venous congestion at −12° HDT. Since subjects felt comfortable with lying in −12° HDT under our experimental conditions, this posture only moderately deteriorates sleep. Obviously, the human body can almost compensate the several fold effects of gravity in HDT posture like an affected CSF circulation, airway obstruction, unusual patterns of propioception and effects on the cardiovascular system

Phylogeny of the tropical tree family Dipterocarpaceae based on nucleotide sequences of the chloroplast RBCL gene

The Dipterocarpaceae, well-known trees of the Asian rain forests, have been variously assigned to Malvales and Theales. The family, if the Monotoideae of Africa (30 species) and South America and the Pakaraimoideae of South America (one species) are included, comprises over 500 species. Despite the high diversity and ecological dominance of the Dipterocarpaceae, phylogenetic relationships within the family as well as between dipterocarps and other angiosperm families remain poorly defined. We conducted parsimony analyses on rbcL sequences from 35 species to reconstruct the phylogeny of the Dipterocarpaceae. The consensus tree resulting from these analyses shows that the members of Dipterocarpaceae, including Monotes and Pakaraimaea, form a monophyletic group closely related to the family Sarcolaenaceae and are allied to Malvales. The present generic and higher taxon circumscriptions of Dipterocarpaceae are mostly in agreement with this molecular phylogeny with the exception of the genus Hopea, which forms a clade with Shorea sections Anthoshorea and Doona. Phylogenetic placement of Dipterocarpus and Dryobalanops remains unresolved. Further studies involving representative taxa from Cistaceae, Elaeocarpaceae, Hopea, Shorea, Dipterocarpus, and Dryobalanops will be necessary for a comprehensive understanding of the phylogeny and generic limits of the Dipterocarpaceae