149 research outputs found

    Non-Waste-Wax-Formwork technology

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    Die heutigen marktgängigen Systemschalungen sind darauf ausgelegt, „günstigen“ Beton schnell und unter Reduktion von Arbeit in einfache Geometrien zu gießen. Es entstehen massenintensive Betonbauteile unter Einsatz von mehr Ressourcen (graue Energie / CO2) als nötig. Durch die Entwicklung digitaler Entwurfs- und Berechnungsprogramme ist es heute theoretisch möglich, in noch nie dagewesener Form filigrane und materialeffiziente Konstruktionen zu realisieren. Ihre Herstellung z.B. aus UHPC erfordert allerdings aufwendige, teure und abfallintensive Sonderschalungen, die nicht wirtschaftlich sind und als Grund gesehen werden können, warum solche Konstruktionen heute nur selten realisiert werden. Hier setzt die vorliegende Arbeit an. Mit der Entwicklung einer digital gefertigten, voll recycelbaren Non-Waste-Wachsschalungstechnologie soll die Lücke zwischen dem digital Planbaren und dem ökonomisch und ökologisch Umsetzbaren geschlossen werden. Diese mit dem Innovationspreis der Zulieferindustrie Betonbauteile 2017 ausgezeichnete Schalungstechnologie basiert dabei auf 100 % wiederverwendbaren technischen Wachsen, die mittels zerspanender CNC Bearbeitung geformt werden. Durch die erreichbare hochpräzise Formgebung ist sie neben Normalbeton insbesondere für feinkörnigen UHPC geeignet. Zu Beginn erfolgt die Selektion eines geeigneten Wachses, wozu die definierten Anforderungen an Sonderschalungen mit den experimentell ermittelten Analyseergebnissen 29 unterschiedlicher Wachse verglichen werden. Neben der Entwicklung eines Verfahrens zur Herstellung großformatiger spannungsarmer Wachsblöcke, werden im Folgenden die, in Zusammenarbeit mit dem Institut für Werkzeugmaschinen und Fertigungstechnik (IWF) der TU Braunschweig ermittelten, optimierten Fräswerkzeuge und Bearbeitungsparameter dargestellt. Zur Evaluation der Non-Waste-Wachsschalungstechnologie bezüglich Gestaltungsfreiheit und Präzision werden anschließend die hergestellten, unterschiedlich geometrisch komplexen Wachsschalungen und Betonbauteile mittels einer Form- und Maßanalyse bewertet. Die Nachhaltigkeit und Wirtschaftlichkeit wird ferner u.a. an verschiedenen realisierten Anwendungsbeispielen aufgezeigt und evaluiert. Zusätzlich wird die prinzipielle Anwendbarkeit von komplexen Wachs-Verdrängungskörpern (Hohlraum-Wachsschalungen) dargestellt. Abschließend werden Ausblicke auf weiterführende Forschungsprojekte am ITE zum Transfer der Technologie in die industrielle Anwendung gegeben.Today's marketable system formworks are designed to pour "cheap” concrete quickly into simple geometries with a reduction in work. This results in mass-intensive concrete structural elements using more resources (grey energy / CO2) than necessary. Through the development of digital design and calculation programs, it is theoretically possible today to realize filigree and material-efficient constructions in an unprecedented form. Their production e.g. from UHPC, however, requires complex, expensive and waste-intensive special formwork, which is not economical and can be seen as a reason why such constructions have rarely been realized. This is the starting point of this thesis. With the development of a digitally manufactured, fully recyclable Non-Waste-Wax-Formwork technology, the gap between the digitally plannable and the economically and ecologically feasible should be closed. This formwork technology, which was awarded with the innovation prize of the supplier industry for concrete components in 2017, is based on 100 % reusable technical waxes, which are formed using CNC machining. The high-precision shaping that can be achieved makes it in addition to normal concrete particularly suitable for fine-grained UHPC. The first step is the selection of a suitable wax by comparing the defined requirements for special formwork with the experimentally determined analysis results of 29 different waxes. In addition to the development of a process for the production of large-format, low-stress wax blocks, the optimized milling tools and machining parameters determined in cooperation with the Institute of Machine Tools and Production Technology (IWF) of TU Braunschweig are presented. In order to evaluate Non-Waste-Wax-Formwork technology in terms of freedom of design and precision, the wax formwork and concrete components produced with different geometric complexity are evaluated by use of a shape and dimension analysis. The sustainability and economic efficiency is further i.a. shown and evaluated on different realized application examples. In addition, the principle applicability of complex wax displacement bodies (cavity wax formwork) is presented. Finally, perspectives on further research projects at the ITE on the transfer of the technology for industrial applications are given

    Learning volition: A longitudinal study of developing intentional awareness in Tourette syndrome

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    Tourette syndrome (TS) is characterized by the presence of involuntary movements (tics) which are, at least partly, generated within ‘voluntary’ motor pathways. Here we reassess 16 TS patients (age 19 ± 2.3 years) who participated in a mental chronometry study of volition 5.5 years previously (Ganos C et al. Cortex. 2015 Mar.; 64:47–54), and 16 age-matched controls. Participants estimated the time of their own voluntary movements (Libet's M judgement), or of conscious intention to make voluntary movements (Libet's W judgement), in separate blocks. We considered M judgement as a control condition. Therefore, the experience of an intention to move occurring prior to actual movement onset, as measured by the W-M gap, was taken as the cardinal feature of volition. Time estimates of the TS group did not differ significantly from controls, for either M or W judgement. Further, M and W time estimates in the TS group had not changed significantly between the two assessments. However, exploratory analyses revealed a strong relation between disease duration and the development of M- and W-judgements: the longer was the disease duration, the less was the developmental increase in the W-M gap (linear regression, p = .003). In conclusion, our results suggest compromised development of experience of volition in developing TS patients. The developmental difficulty in processing internal premotor signals for voluntary actions could reflect the chronic persistence of tics from adolescence to adulthood

    Good images, effective messages? Working with students and educators on academic practice understanding

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    Work at Northumbria University has focussed on activity that extends opportunities for students to engage directly with the skills development necessary for sound academic practice. This has included highly visual campaigns on the "Plagiarism trap", providing access to Turnitin plagiarism detection software, guides and sessions to highlight use of associated referencing tools. Sessions on a variety of topics, such as supporting study skills and reading originality reports, have been provided for students on taught, undergraduate and postgraduate programmes. This provision has included students working on collaborative partners' sites and also those on research programmes. Alongside the activities with students, "designing out" approaches have been embedded in staff development within the educator community at Northumbria. Formative use of Turnitin is integrated throughout programmes and academic practice development is formally recognised within the University Learning and Teaching Strategy's focus on information literacy. This article outlines and reviews these activities in a critical institutional context and evaluates responses from a variety of students and educators to determine how effective these measures have been

    The spectrum of involuntary vocalizations in humans: A video atlas

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    In clinical practice, involuntary vocalizing behaviors are typically associated with Tourette syndrome and other tic disorders. However, they may also be encountered throughout the entire tenor of neuropsychiatry, movement disorders, and neurodevelopmental syndromes. Importantly, involuntary vocalizing behaviors may often constitute a predominant clinical sign, and, therefore, their early recognition and appropriate classification are necessary to guide diagnosis and treatment. Clinical literature and video‐documented cases on the topic are surprisingly scarce. Here, we pooled data from 5 expert centers of movement disorders, with instructive video material to cover the entire range of involuntary vocalizations in humans. Medical literature was also reviewed to document the range of possible etiologies associated with the different types of vocalizing behaviors and to explore treatment options. We propose a phenomenological classification of involuntary vocalizations within different categorical domains, including (1) tics and tic‐like vocalizations, (2) vocalizations as part of stereotypies, (3) vocalizations as part of dystonia or chorea, (4) continuous vocalizing behaviors such as groaning or grunting, (5) pathological laughter and crying, (6) vocalizations resembling physiological reflexes, and (7) other vocalizations, for example, those associated with exaggerated startle responses, as part of epilepsy and sleep‐related phenomena. We provide comprehensive lists of their associated etiologies, including neurodevelopmental, neurodegenerative, neuroimmunological, and structural causes and clinical clues. We then expand on the pathophysiology of the different vocalizing behaviors and comment on available treatment options. Finally, we present an algorithmic approach that covers the wide range of involuntary vocalizations in humans, with the ultimate goal of improving diagnostic accuracy and guiding appropriate treatment

    Is it cheating or learning the craft of writing? Using Turnitin to help students avoid plagiarism

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    Plagiarism is a growing problem for universities, many of which are turning to software detection for help in detecting and dealing with it. This paper explores issues around plagiarism and reports on a study of the use of Turnitin in a new university. The purpose of the study was to inform the senior management team about the plagiarism policy and the use of Turnitin. The study found that staff and students largely understood the university’s policy and Turnitin’s place within it, and were very supportive of the use of Turnitin in originality checking. Students who had not used Turnitin were generally keen to do so. The recommendation to the senior management team, which was implemented, was that the use of Turnitin for originality checking should be made compulsory where possible - at the time of the study the use of Turnitin was at the discretion of programme directors. A further aim of the study was to contribute to the sector’s body of knowledge. Prevention of plagiarism through education is a theme identified by Badge and Scott (2009) who conclude an area lacking in research is "investigation of the impact of these tools on staff teaching practices". Although a number of recent studies have considered educational use of Turnitin they focus on individual programmes or subject areas rather than institutions as a whole and the relationship with policy

    When One Hemisphere Takes Control: Metacontrol in Pigeons (Columba livia)

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    Vertebrate brains are composed of two hemispheres that receive input, compute, and interact to form a unified response. How the partially different processes of both hemispheres are integrated to create a single output is largely unknown. In some cases one hemisphere takes charge of the response selection--a process known as metacontrol. Thus far, this phenomenon has only been shown in a handful of studies with primates, mostly conducted in humans. Metacontrol, however, is even more relevant for animals like birds with laterally placed eyes and complete chiasmatic decussation since visual input to the hemispheres is largely different.Homing pigeons (Columba livia) were trained with a color discrimination task. Each hemisphere was trained with a different color pair and therefore had a different experience. Subsequently, the pigeons were binocularly examined with two additional stimuli that combined the positive color of one hemisphere with a negative color that had been shown to the other, omitting the availability of a coherent solution and confronting the pigeons with a conflicting situation. Some of the pigeons responded to both stimuli, indicating that none of the hemispheres dominated the overall preference. Some birds, however, responded primarily to one of the conflicting stimuli, showing that they based their choice on the left- or right-monocularly learned color pair, indicating hemispheric metacontrol.We could demonstrate for the first time that metacontrol is a widespread phenomenon that also exists in birds, and thus in principle requires no corpus callosum. Our results are closely similar to those in humans: monocular performance was higher than binocular one and animals displayed different modes of hemispheric dominance. Thus, metacontrol is a dynamic and widely distributed process that possibly constitutes a requirement for all animals with a bipartite brain to confront the problem of choosing between two hemisphere-bound behavioral options

    A Stated Preference Investigation into the Chinese Demand for Farmed vs. Wild Bear Bile

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    Farming of animals and plants has recently been considered not merely as a more efficient and plentiful supply of their products but also as a means of protecting wild populations from that trade. Amongst these nascent farming products might be listed bear bile. Bear bile has been exploited by traditional Chinese medicinalists for millennia. Since the 1980s consumers have had the options of: illegal wild gall bladders, bile extracted from caged live bears or the acid synthesised chemically. Despite these alternatives bears continue to be harvested from the wild. In this paper we use stated preference techniques using a random sample of the Chinese population to estimate demand functions for wild bear bile with and without competition from farmed bear bile. We find a willingness to pay considerably more for wild bear bile than farmed. Wild bear bile has low own price elasticity and cross price elasticity with farmed bear bile. The ability of farmed bear bile to reduce demand for wild bear bile is at best limited and, at prevailing prices, may be close to zero or have the opposite effect. The demand functions estimated suggest that the own price elasticity of wild bear bile is lower when competing with farmed bear bile than when it is the only option available. This means that the incumbent product may actually sell more items at a higher price when competing than when alone in the market. This finding may be of broader interest to behavioural economists as we argue that one explanation may be that as product choice increases price has less impact on decision making. For the wildlife farming debate this indicates that at some prices the introduction of farmed competition might increase the demand for the wild product

    Factors associated with worse lung function in cystic fibrosis patients with persistent staphylococcus aureus

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    Background Staphylococcus aureus is an important pathogen in cystic fibrosis (CF). However, it is not clear which factors are associated with worse lung function in patients with persistent S. aureus airway cultures. Our main hypothesis was that patients with high S. aureus density in their respiratory specimens would more likely experience worsening of their lung disease than patients with low bacterial loads. Methods Therefore, we conducted an observational prospective longitudinal multi-center study and assessed the association between lung function and S. aureus bacterial density in respiratory samples, co-infection with other CF-pathogens, nasal S. aureus carriage, clinical status, antibiotic therapy, IL-6- and IgG-levels against S. aureus virulence factors. Results 195 patients from 17 centers were followed; each patient had an average of 7 visits. Data were analyzed using descriptive statistics and generalized linear mixed models. Our main hypothesis was only supported for patients providing throat specimens indicating that patients with higher density experienced a steeper lung function decline (p<0.001). Patients with exacerbations (n = 60), S. aureus small-colony variants (SCVs, n = 84) and co-infection with Stenotrophomonas maltophilia (n = 44) had worse lung function (p = 0.0068; p = 0.0011; p = 0.0103). Patients with SCVs were older (p = 0.0066) and more often treated with trimethoprim/sulfamethoxazole (p = 0.0078). IL-6 levels positively correlated with decreased lung function (p<0.001), S. aureus density in sputa (p = 0.0016), SCVs (p = 0.0209), exacerbations (p = 0.0041) and co-infections with S. maltophilia (p = 0.0195) or A. fumigatus (p = 0.0496). Conclusions In CF-patients with chronic S. aureus cultures, independent risk factors for worse lung function are high bacterial density in throat cultures, exacerbations, elevated IL-6 levels, presence of S. aureus SCVs and co-infection with S. maltophilia

    Does Global Warming Increase Establishment Rates of Invasive Alien Species? A Centurial Time Series Analysis

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    BACKGROUND: The establishment rate of invasive alien insect species has been increasing worldwide during the past century. This trend has been widely attributed to increased rates of international trade and associated species introductions, but rarely linked to environmental change. To better understand and manage the bioinvasion process, it is crucial to understand the relationship between global warming and establishment rate of invasive alien species, especially for poikilothermic invaders such as insects. METHODOLOGY/PRINCIPAL FINDINGS: We present data that demonstrate a significant positive relationship between the change in average annual surface air temperature and the establishment rate of invasive alien insects in mainland China during 1900-2005. This relationship was modeled by regression analysis, and indicated that a 1 °C increase in average annual surface temperature in mainland China was associated with an increase in the establishment rate of invasive alien insects of about 0.5 species year⁻¹. The relationship between rising surface air temperature and increasing establishment rate remained significant even after accounting for increases in international trade during the period 1950-2005. Moreover, similar relationships were detected using additional data from the United Kingdom and the contiguous United States. CONCLUSIONS/SIGNIFICANCE: These findings suggest that the perceived increase in establishments of invasive alien insects can be explained only in part by an increase in introduction rate or propagule pressure. Besides increasing propagule pressure, global warming is another driver that could favor worldwide bioinvasions. Our study highlights the need to consider global warming when designing strategies and policies to deal with bioinvasions

    Simian Varicella Virus Infection of Rhesus Macaques Recapitulates Essential Features of Varicella Zoster Virus Infection in Humans

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    Simian varicella virus (SVV), the etiologic agent of naturally occurring varicella in primates, is genetically and antigenically closely related to human varicella zoster virus (VZV). Early attempts to develop a model of VZV pathogenesis and latency in nonhuman primates (NHP) resulted in persistent infection. More recent models successfully produced latency; however, only a minority of monkeys became viremic and seroconverted. Thus, previous NHP models were not ideally suited to analyze the immune response to SVV during acute infection and the transition to latency. Here, we show for the first time that intrabronchial inoculation of rhesus macaques with SVV closely mimics naturally occurring varicella (chickenpox) in humans. Infected monkeys developed varicella and viremia that resolved 21 days after infection. Months later, viral DNA was detected only in ganglia and not in non-ganglionic tissues. Like VZV latency in human ganglia, transcripts corresponding to SVV ORFs 21, 62, 63 and 66, but not ORF 40, were detected by RT-PCR. In addition, as described for VZV, SVV ORF 63 protein was detected in the cytoplasm of neurons in latently infected monkey ganglia by immunohistochemistry. We also present the first in depth analysis of the immune response to SVV. Infected animals produced a strong humoral and cell-mediated immune response to SVV, as assessed by immunohistology, serology and flow cytometry. Intrabronchial inoculation of rhesus macaques with SVV provides a novel model to analyze viral and immunological mechanisms of VZV latency and reactivation
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