802 research outputs found
Computer-controlled stereoscopic profiling
This paper presents a computer controlled stereoscopic vision system that will profile the contour and shape of the bottom of the human foot in its natural weight bearing position. The design will have no moving parts and will be restricted to an error of no more than {dollar}\pm{dollar}1 mm; Stereoscopic vision was chosen as the solution to profiling mainly because its use for this purpose is well documented. It is used in many fields that require range resolution. Mechanical engineers have used it in the development of robot vision for years and their applications range from control systems for robot welding to the determination of metal fatigue in aircraft (2). Radar engineers have used it since the early 1940\u27s to determine the range of incoming flying objects (1). Many other fields have used it for even more far reaching purposes. Our use is another in that long list
Investigation of Non-Conventional Bio-Derived Fuels for Hybrid Rocket Motors
Non-conventional bio-derived fuels have been evaluated for use in hybrid rocket motors. Tests were conducted at combustion pressures in the range of 100 â 220 psig and thrust levels of 40 â 170 newtons. Beeswax was tested with oxygen as the oxidizer and showed a regression rate at least three times as high as traditional hybrid propellant combinations such as hydroxyl-terminated polybutadiene (HTPB) and liquid oxygen (LOX). This provides the promise of a high thrust hybrid rocket motor using a simple, single port geometry and overcomes the main weakness of traditional hybrid rocket motor propellants, which are low regression rates. Beeswax was also tested with nitrous oxide as an oxidizer, but further testing is needed to attain high enough combustion chamber pressures to achieve stable combustion. Experimental evaluation of the specific impulse for beeswax and oxygen was moderately successful for lab scale testing, but needs further refinement. Analytical studies were performed to evaluate the theoretical performance of non-conventional hybrid rocket motors. This analysis indicates beeswax, lard, a mixture of paraffin and lard, and combinations of beeswax and aluminum should all perform better than traditional hybrid rocket propellants considered when burned with oxygen. For a combustion chamber pressure of 500.38 psig, beeswax and oxygen yielded a maximum specific impulse of 327 s. The high specific impulse combined with a high regression rate combine to make beeswax and oxygen a potentially high performing hybrid rocket motor propellant for launch vehicles, suborbital rockets, or orbital kick motors
Synthesis and MALDI-ToF characterization of dendronized poly(ethylene glycol)s
Well-defined hybrids of linear poly(ethylene glycol)s (PEGs) and dendritic polyesters were prepared via the dendronization of the alcohol end groups of the mono and difunctional linear PEGs. Though useful for rudimentary product characterization, GPC and NMR could not verify the overall structural purity of these linear-dendritic hybrids. On the other hand, the detailed data provided by MALDI-ToF mass spectrometry enabled confirmation of the high structural purity of the dendronized PEGs at each step of the dendronization procedure. The well-defined number of functionalities on these dendronized PEGs, renders them particularly useful for research in the biomedical sphere where functionality and purity are of the utmost importance. The MALDI-ToF mass spectrometric approach described herein represents a valuable technique for detailed monitoring of these dendronization reactions, as well as a variety of other polymer end group modifications.HĂbridos bem definidos de poli(etilenoglicol) lineares (PEGs) e poliĂ©steres dendrimĂ©ricos foram preparados via "dendronização" de ĂĄlcool e grupos de PEGs lineares mono e bifuncionais. Embora Ășteis para a caracterização rudimentar de produtos, Cromatografia por Permeação em Gel e RMN podem nĂŁo demonstrar a pureza estrutural global desses hĂbridos lineares dendrĂticos. Por outro lado, informaçÔes detalhadas provenientes de espectrometria de massas MALDI-ToF permitiram a confirmação de elevada pureza estrutural de PEGs "dendronizados" em cada passo do processo de "dendronização". O nĂșmero de funcionalidades bem definidas destes PEGs "dendronizados", torna-os particularmente Ășteis para pesquisa na ĂĄrea biomĂ©dica, na qual funcionalidade e pureza sĂŁo de grande importĂąncia. A abordagem de espectrometria de massas MALDI-ToF descrita aqui representa uma tĂ©cnica valiosa para o monitoramento detalhado destas reaçÔes de "dendronização", bem como diversas modificaçÔes de outros polĂmeros e grupos
Mainstreaming ecosystem science in spatial planning practice : exploiting a hybrid opportunity space
This paper develops a framework for improved mainstreaming of ecosystem science in policy and decision-making within a spatial planning context. Ecosystem science is advanced as a collective umbrella to capture a body of work and approaches rooted in social-ecological systems thinking, spawning a distinctive ecosystem terminology: ecosystem approach, ecosystem services, ecosystem services framework and natural capital. The interface between spatial planning and ecosystem science is explored as a theoretical opportunity space to improve mainstreaming processes adapting Rogersâ (2003) diffusion model. We introduce the twin concepts of hooks (linking ecosystem science to a key policy or legislative term, duty or priority that relate to a particular user group) and âbridgesâ (linking ecosystem science to a term, concept or policy priority that is used and readily understood across multiple groups and publics) as translational mechanisms in transdisciplinary mainstreaming settings. We argue that ecosystem science can be embedded into the existing work priorities and vocabularies of spatial planning practice using these hooks and bridges. The resultant framework for mainstreaming is then tested, drawing on research funded as part of the UK National Ecosystem Assessment Follow-On programme (2012-2014), within 4 case studies; each reflecting different capacities, capabilities, opportunities and barriers. The results reveal the importance of leadership, political buy in, willingness to experiment outside established comfort zones and social learning as core drivers supporting mainstreaming processes. Whilst there are still significant challenges in mainstreaming in spatial planning settings, the identification and use of hooks and bridges collectively, enables traction to be gained for further advances; moving beyond the status quo to generate additionality and potential behaviour change within different modes of mainstreaming practice. This pragmatic approach has global application to help improve the way nature is respected and taken account of in planning systems nationally and globally
Longitudinal analysis of the developing rhesus monkey brain using magnetic resonance imaging: birth to adulthood.
We have longitudinally assessed normative brain growth patterns in naturalistically reared Macaca mulatta monkeys. Postnatal to early adulthood brain development in two cohorts of rhesus monkeys was analyzed using magnetic resonance imaging. Cohort A consisted of 24 rhesus monkeys (12 male, 12 female) and cohort B of 21 monkeys (11 male, 10 female). All subjects were scanned at 1, 4, 8, 13, 26, 39, and 52Â weeks; cohort A had additional scans at 156Â weeks (3Â years) and 260Â weeks (5Â years). Age-specific segmentation templates were developed for automated volumetric analyses of the T1-weighted magnetic resonance imaging scans. Trajectories of total brain size as well as cerebral and subcortical subdivisions were evaluated over this period. Total brain volume was about 64Â % of adult estimates in the 1-week-old monkey. Brain volume of the male subjects was always, on average, larger than the female subjects. While brain volume generally increased between any two imaging time points, there was a transient plateau of brain growth between 26 and 39Â weeks in both cohorts of monkeys. The trajectory of enlargement differed across cortical regions with the occipital cortex demonstrating the most idiosyncratic pattern of maturation and the frontal and temporal lobes showing the greatest and most protracted growth. A variety of allometric measurements were also acquired and body weight gain was most closely associated with the rate of brain growth. These findings provide a valuable baseline for the effects of fetal and early postnatal manipulations on the pattern of abnormal brain growth related to neurodevelopmental disorders
NCPT â managing environmental gains and losses
How a new practical tool enables non-specialists to systematically assess and manage planning and development impacts on natural capital
Continuous Truth II: Reflections
Abstract. In the late 1960s, Dana Scott first showed how the Stone-Tarski topological interpretation of Heytingâs calculus could be extended to model intuitionistic analysis; in particular Brouwerâs continuity prin-ciple. In the early â80s we and others outlined a general treatment of non-constructive objects, using sheaf modelsâconstructions from topos theoryâto model not only Brouwerâs non-classical conclusions, but also his creation of ânew mathematical entitiesâ. These categorical models are intimately related to, but more general than Scottâs topological model. The primary goal of this paper is to consider the question of iterated extensions. Can we derive new insights by repeating the second act? In Continuous Truth I, presented at Logic Colloquium â82 in Florence, we showed that general principles of continuity, local choice and local com-pactness hold in the gros topos of sheaves over the category of separable locales equipped with the open cover topology. We touched on the question of iteration. Here we develop a more gen-eral analysis of iterated categorical extensions, that leads to a reflection schema for statements of predicative analysis. We also take the opportunity to revisit some aspects of both Continuous Truth I and Formal Spaces (Fourman & Grayson 1982), and correct two long-standing errors therein
In What Ways Are Deep Neural Networks Invariant and How Should We Measure This?
It is often said that a deep learning model is "invariant" to some specific
type of transformation. However, what is meant by this statement strongly
depends on the context in which it is made. In this paper we explore the nature
of invariance and equivariance of deep learning models with the goal of better
understanding the ways in which they actually capture these concepts on a
formal level. We introduce a family of invariance and equivariance metrics that
allows us to quantify these properties in a way that disentangles them from
other metrics such as loss or accuracy. We use our metrics to better understand
the two most popular methods used to build invariance into networks: data
augmentation and equivariant layers. We draw a range of conclusions about
invariance and equivariance in deep learning models, ranging from whether
initializing a model with pretrained weights has an effect on a trained model's
invariance, to the extent to which invariance learned via training can
generalize to out-of-distribution data.Comment: To appear at NeurIPS 202
SMEs and Certified Management Standards: The Effect of Motives and Timing on Implementation and Commitment
Existing research on certifiable management standards (CMS) and corporate social responsibility (CSR) tends to focus on large companies and is characterised by disagreement about the role of these standards as drivers of CSR. We contribute to the literature by shifting the analytical focus to the behaviour of small and medium-sized enterprises (SMEs) that subscribe to multiple CSR related standards. We argue that, in respect of motive and commitment, SMEs are not as different from large companies as the literature suggests, as they are guided by similar institutional and economic motives. Results, based on ISO 9001, ISO 14001 and OHSAS 18001 certified SMEs in Greece, demonstrate that later adopters are more susceptible to coercive and mimetic motives and are less likely to commit fully to the CMS requirements, while earlier adopters react to normative motives and considerations of internal efficiency gains and tend to carry out CMS requirements with greater diligence
The Opportunities for Digital Conservation in Making Smarter Cities More Natural
Globally, the pace of urbanisation is increasing with 68 % of the worldâs population projected to be urban by 2050. The quality of life for and engagement of these urban citizens is coming to the fore as a key issue for urban planners and decision makers as they pursue place-based initiatives to optimise city performance and sustainability credentials. Decision makers tackling multiple urban discourses such as the Smart City and Natural (or green or biophilic) Cities, which now heavily influence research policy and practice agendas, find themselves addressing tricky inter-disciplinary problems. Traditional sectoral silo approaches often hinder integration, reduce the quality of the natural environment and so often fail to deliver the multiple benefits expected by communities. Drawing on a desk based systematic review of the evidence base and a workshop involving key city stakeholders, we consider how digital conservation might contribute to new integrated approaches that consider people and nature together to contribute to the wider need to deliver public services in more innovative ways within cities that are both smart and natural. We suggest that added value is identified through the combination of new technologies and this potential new governance framework, to evidence and deliver the benefits of nature for urban citizens. This builds in citizen engagement for enhancing the natural environment by embedding and exploiting the potential of digital solutions. We comment on the strengths and weaknesses of how this new conceptual approach can improve integration of service delivery, whether it can also help overcome some of the problems and risks associated with digital conservation and if, by encouraging innovation through participatory governance, also help to inform the design a more inclusive smarter and natural city.
Key words: smart, natural, digital conservation, green, co-production
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