Axial and radial thermal responses of energy pile under six storey residential building

The axial and radial thermal responses of a cast-in-place energy pile, 10 m long and 0.6 m in diameter, installed in unsaturated sand under a six storey building are examined during a heating–cooling cycle. The instrumentation in the pile was configured to compare radial and axial thermal responses at the same elevations and to evaluate the temperature and axial thermal stress distribution across the cross-sectional area of the pile. The magnitudes of the axial thermal strains were more constrained than the radial thermal strains at all depths, leading to the development of axial and radial thermal stresses of up to –4.5 and –0.015 MPa, respectively, for a change in average pile temperature of 24.1 °C. The magnitudes of the radial thermal stresses with changes in pile temperature were significantly lower than the axial thermal stresses at all depths of the pile, indicating that the radial thermal expansion had negligible effects on the development of axial thermal strains and stresses. The temperature distribution over the cross section of the pile showed low variations at all depths, indicating that it would be justified to consider a uniform temperature distribution at least in piles of similar dimensions and with even heat exchanger layouts

Axial and radial thermal responses of an energy pile under a 6-storey residential building

The axial and radial thermal responses of a cast-in place 10 m long energy pile and 0.6 m in diameter, installed in unsaturated sand under a 6-storey building, are examined during a heating-cooling cycle. The instrumentation in the pile was configured to compare radial and axial thermal responses at the same elevations and to evaluate the temperature and axial thermal stress distribution across the cross-sectional area of the pile. The magnitudes of the axial thermal strains were more constrained than the radial thermal strains at all depths, leading to the development of axial and radial thermal stresses of up to -4.5 MPa and -0.015 MPa, respectively, for a change in average pile temperature of 24.1°C. The magnitudes of the radial thermal stresses with changes in pile temperature were significantly lower than the axial thermal stresses at all depths of the pile, indicating that the radial thermal expansion had negligible effects on the development of axial thermal strains and stresses. The temperature distribution over the cross-section of the pile showed low variations at all depths, indicating that it would be justified to consider a uniform temperature distribution at least in piles of similar dimensions and with even heat exchanger layouts.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Recruitment and baseline characteristics of young adults at risk of early-onset knee osteoarthritis after ACL reconstruction in the SUPER-Knee trial

Objectives:The study aims to (1) report the process of recruiting young adults into a secondary knee osteoarthritis prevention randomised controlled trial (RCT) after anterior cruciate ligament reconstruction (ACLR); (2) determine the number of individuals needed to be screened to include one participant (NNS) and (3) report baseline characteristics of randomised participants. Methods:The SUpervised exercise-therapy and Patient Education Rehabilitation (SUPER)-Knee RCT compares SUPER and minimal intervention for young adults (aged 18-40 years) with ongoing symptoms (ie, mean score of &lt;80/100 from four Knee injury and Osteoarthritis Outcome Score subscales (KOOS4)) 9-36 months post-ACLR. The NNS was calculated as the number of prospective participants screened to enrol one person. At baseline, participants provided medical history, completed questionnaires (demographic, injury/surgery, rehabilitation characteristics) and underwent physical examination. Results:1044 individuals were screened to identify 567 eligible people, from which 184 participants (63% male) enrolled. The sample of enrolled participants was multicultural (29% born outside Australia; 2% Indigenous Australians). The NNS was 5.7. For randomised participants, mean±SD age was 30±6 years. The mean body mass index was 27.3±5.2 kg/m2, with overweight (43%) and obesity (21%) common. Participants were, on average, 2.3 years post-ACLR. Over half completed &lt;8 months of postoperative rehabilitation, with 56% having concurrent injury/surgery to meniscus and/or cartilage. The most affected KOOS (0=worst, 100=best) subscale was quality of life (mean 43.7±19.1). Conclusion:Young adults post-ACLR were willing to participate in a secondary osteoarthritis prevention trial. Sample size calculations should be multiplied by at least 5.7 to provide an estimate of the NNS. The SUPER-Knee cohort is ideally positioned to monitor and intervene in the early development and trajectory of osteoarthritis.</p