Adhesively-bonded GFRP-glass sandwich components for structurally efficient glazing applications

Composite sandwich structures made of thick glass face sheets adhesively-bonded to glass fibre-reinforced polymer (GFRP) core profiles have the potential to outperform existing non-composite glazing configurations but their feasibility has yet to be investigated and there are no analytical models that describe their structural response. This paper presents the new analytical models for predicting deflections and strains in adhesively-bonded GFRP-glass sandwich beams. The new analytical models successfully account for: the shear deformations of the core and adhesive layers; the local bending of the constituent parts about their centroidal axes; and the global bending of the sandwich component as a whole. The deflections and strains predicted by analytical models are validated by finite element simulations and compared with the results of destructive tests performed on adhesively-bonded GFRP-glass beams in a four-point bending configuration. The analytical models were also evaluated for alternative GFRP-glass configurations tested by others. The GFRP-glass beams specially assembled in this study confirm the physical feasibility of constructing these proposed components.The authors would like to thank the Engineering and Physical Sciences Research Council – United Kingdom for the financial support of the project

Geographic Determinants of Healthy Lifestyle Change in a Community-Based Exercise Prescription Delivered in Family Practice

Background: Evidence is unequivocal that exercise training can improve health outcomes. However, despite this evidence, adoption of healthy lifestyles is poor. The physical environment is one possible determinant of successful adoption of healthy lifestyles that could influence outcomes in community-based intervention strategies. We developed a novel exercise prescription delivered in two different cohorts of older sedentary adults—one delivered by family physicians to patients with identified cardiovascular risk factors (CRF) and the other delivered at a community exercise facility to a larger cohort of healthy sedentary adults (HSA). We then determined whether the place of residence and proximity to facilities promoting physical activity and healthy or unhealthy eating could influence clinical changes related to these community-based exercise prescriptions.Methods: Two different cohorts of older patients were administered similar exercise prescriptions. The CRF cohort was a sedentary group of 41 older adults with either high-normal blood pressure (120–139 mmHg/85–89 mmHg) or impaired glucose tolerance (fasting glucose 6.1–6.9 mmol/l) who were prescribed exercise by their family physicians at baseline and followed over 12 months. The HSA cohort consisted of 159 sedentary older adults who were prescribed a similar exercise prescription and then participated in a chronic training program over 5 years at a community-based training facility. Out- comes of interest were change in fitness (VO2max), resting systolic blood pressure (rSBP) and body mass index (BMI). GIS-determined shortest distance to local facilities promoting physical activity and healthy versus unhealthy were compared at baseline and follow up using simple logistic regression.Those subjects in CRF group were further identified as responders (exhibited an above average change in VO2max) and were then compared to non-responders according to their patterns of proximity to physical activity and eating facilities.Results: In the CRF cohort at baseline, greater GIS-distance to golf courses correlated with higher rSBP (r = 0.38, p = 0.02) while greater distance to bike paths correlated with greater BMI (r = 0.32, p = 0.05). CRF responders who lived closer to a park had higher BMI (r = −0.46, p = 0.05) while no other relationship among responders and proximity to either physical activity or eating facilities was observed. CRF non-responders lived closer to formal physical activity facilities (community centres) and higher fat eating facilities. In the HSA cohort, higher fitness was correlated with greater distance to both formal and informal physical activity facilities (baseball fields or dance studios) while this was also correlated with a higher rSBP (r = 0.17, p = 0.04). In general, physical activity facilities were often located near higher-fat eating facilities regardless of cohort.Conclusion: Those prescribed exercise by their family physician for the presence of health risk tended to closer to any type of physical activity facility compared to those who joined an exercise program on their own. A positive response to the intervention at 12 months was associated with closer access to informal physical activity facilities while non-responders lived closer to both types of physical activity facility as well as high fat eating facilities. In contrast, healthy chronic exercise trainees in the community did not show any meaningful relation between fitness and proximity to healthy lifestyle facilities. Hence, the access to facilities is not as important to those who adopt physical activity on their own whereas those targeted by physicians may be influenced by access. Furthermore, the response or lack thereof to exercise interventions in those at risk may be influenced by proximity to both physical activity and unhealthy eating facilities

Knowledge-Based Engineering in the design for manufacture of prefabricated façades: current gaps and future trends

The use of prefabricated façades provides a timely means to increase efficiency in the delivery of buildings, while maximising the expected environmental service performance. In order to achieve high performance and low cost, these products require manufacturability and supply chain knowledge to be integrated earlier than usual in the design process. Knowledge-Based Engineering (KBE) applications can potentially fulfil this need by providing a digital Product Model that informs designers about manufacturability aspects and expected performance. This paper explores the currently-available digital tools, as well as KBE and its applicability in façade design. It is first demonstrated that there is a fundamental gap in state-of-the-art digital tools: rather than integrating design principles and manufacturing constraints, existing and emerging tools continue to focus on single-disciplines with no consideration for the actual manufacturing stage. The applicability of KBE is then evaluated by reviewing the current use of this approach in the building and other industries, namely, aerospace and shipbuilding. It is found that, although KBE is rarely used in facade design, there are significant opportunities for it to be applied in this sector, due to the similarity in terms of design tasks and priorities with the two other industries reviewed in this paper.The authors would like to thank the Engineering and Physical Science Research Council (EPSRC) and Laing O’Rourke Plc for supporting the present research programme

Knowledge-rich optimisation of prefabricated façades to support conceptual design

One of the principal challenges in façade design is to support the architectural intent by devising technically viable (i.e. standard-compliant and manufacturable) solutions from as early as possible in the design stage. This is increasingly relevant as prefabricated façades increase in complexity and bespokedness in response to current societal, financial and environmental challenges. In this paper a process that addresses this challenge is presented. The process consists of two sub-processes 1) to build product-oriented knowledge bases and digital tools for supporting design on a project-by-project basis and 2) to help designers identify a set of optimal solutions that consider the façade-specific trade-off between architectural intent and performance requirements, while meeting the largest number of production-related constraints. This process was applied to a case study and the results were compared with those obtained from a recently-developed façade. It was found that, although the proposed process produces optimal solutions that are approximated, designers can benefit from more control over the product’s manufacturability, performance and architectural intent in less time.Laing O'Rourke pl

Validity of values for metabolic equivalents of task during submaximal all-extremity exercise and reliability of exercise responses in frail older adults

Background and Purpose. Physical therapists and rehabilitation professionals in hospital and long-term care centers are using all-extremity semirecumbent exercise machines in their treatment programs. This study was undertaken to investigate the concurrent validity of values for software-generated metabolic equivalents of task (MET) from an all-extremity semirecumbent exercise machine and directly measured values for MET from a portable metabolic unit across a range of submaximal exercise intensities. A second purpose of this study was to determine the test-retest reliability of oxygen consumption and heart rate responses in older adults between standardized sessions of submaximal all-extremity aerobic exercise. Subjects and Methods. The study participants were 18 older adults (mean age=82 years, SD=5; 3 women, 15 men) who were living in long-term care centers and who completed 2 test sessions of a standardized exercise protocol 1 week apart. The exercise protocol included a warm-up period, three 4-minute stages of exercise at incremental workload levels, and a cool-down period. The breath-by-breath metabolic data from the portable metabolic unit, heart rate, MET values from the exercise machine, Borg Rating of Perceived Exertion, and watts were recorded continuously throughout the exercise protocol. Results. The concurrent validity of the MET values from the exercise machine and the portable metabolic unit ranged from very good to excellent on both day 1 and day 2 (r=.85-.97). The test-retest reliability of subjects\u27 heart rate responses and MET values from the portable metabolic unit was moderate to high across submaximal exercise intensities (intraclass correlation coefficients [2,1]=.85-.91). Discussion and Conclusion. The exercise machine software-generated MET values were representative of directly measured oxygen consumption values across a range of submaximal intensities during all-extremity semirecumbent exercise in older adults with multisystem impairments. © 2008 American Physical Therapy Association

Threshold berg balance scale scores for gait-aid use in elderly subjects: A secondary analysis

Purpose: To determine the threshold Berg Balance Scale (BBS) scores that discriminate among levels of gait-aid use in elderly subjects. Methods: A secondary analysis of data combined from two projects was performed. Both projects determined BBS performance, self-selected gait speed, and gait-aid use in samples of community-dwelling, independently ambulant individuals older than 65 years of age. Receiver operating characteristic curves were used to identify BBS scores that optimized identification of individuals with different levels of ambulation. Results: Previously determined associations between BBS score and various indicators of ambulatory ability were reproduced with the combined data set. Threshold BBS scores were identified for ability to walk without an aid (≥49/56) and ability to walk without a four-wheeled walker (≥43/56). The percent agreement values for the identified threshold scores ranged from 51% to 87%. Conclusions: Although some threshold BBS scores could be determined, the accuracies of the scores render them of limited use for guiding gait-aid prescription in individual clients

Qualitative analysis of patient responses to the ABCD FreeStyle Libre audit questionnaire

The Abbott FreeStyle Libre® flash glucose monitoring system is a novel sensor‐based, factory‐calibrated device that allows individuals with diabetes to monitor their interstitial glucose levels, capture up to 8 hours of interstitial glucose data, and predict future changes in interstitial glucose by scanning a temporary implantable glucose sensor with a reader device or compatible mobile phone. The study aim was to determine whether use of a flash glucose monitoring system had an impact on quality of life and to explore why this was the case. Raw data were collected as part of a brief semi‐structured interview supported by the ABCD FreeStyle Libre Follow‐Up Visit Data Collection form. Data were collected pragmatically at outpatient clinic follow‐up visits, and the first 40 patients to complete six months of continuous use were included in the study. Feedback on use of the device was overwhelmingly (although not unanimously) positive. A number of basic themes were identified independently by the investigators, which were then grouped into four organising themes: Contrast with capillary blood glucose monitoring; Impact on hypoglycaemia experience; Glycaemic control and complications; and Improved wellbeing and quality of life. These themes are analysed and illustrated in the article

Renormalization group and 1/N expansion for 3-dimensional Ginzburg-Landau-Wilson models

A renormalization-group scheme is developed for the 3-dimensional O($2N$)-symmetric Ginzburg-Landau-Wilson model, which is consistent with the use of a 1/N expansion as a systematic method of approximation. It is motivated by an application to the critical properties of superconductors, reported in a separate paper. Within this scheme, the infrared stable fixed point controlling critical behaviour appears at $z=0$, where $z=\lambda^{-1}$ is the inverse of the quartic coupling constant, and an efficient renormalization procedure consists in the minimal subtraction of ultraviolet divergences at $z=0$. This scheme is implemented at next-to-leading order, and the standard results for critical exponents calculated by other means are recovered. An apparently novel result of this non-perturbative method of approximation is that corrections to scaling (or confluent singularities) do not, as in perturbative analyses, appear as simple power series in the variable $y=zt^{\omega\nu}$. At least in three dimensions, the power series are modified by powers of $\ln y$.Comment: 20 pages; 5 figure

Critical-point scaling function for the specific heat of a Ginzburg-Landau superconductor

If the zero-field transition in high temperature superconductors such as YBa_2Cu_3O_7-\delta is a critical point in the universality class of the 3-dimensional XY model, then the general theory of critical phenomena predicts the existence of a critical region in which thermodynamic functions have a characteristic scaling form. We report the first attempt to calculate the universal scaling function associated with the specific heat, for which experimental data have become available in recent years. Scaling behaviour is extracted from a renormalization-group analysis, and the 1/N expansion is adopted as a means of approximation. The estimated scaling function is qualitatively similar to that observed experimentally, and also to the lowest-Landau-level scaling function used by some authors to provide an alternative interpretation of the same data. Unfortunately, the 1/N expansion is not sufficiently reliable at small values of N for a quantitative fit to be feasible.Comment: 20 pages; 4 figure