Design of cylindrical plastic pipe linings to resist buckling due to collapse pressures

Flexible (non-bonded) polymeric sewer linings are used extensively to renovate both gravity and pressure pipes. Linings for both types of pipe are subject to collapse pressures, and in the case of gravity pipes this is the dominant source of loading; the efficient design of linings to sustain collapse pressures is therefore an important problem. In this paper, the buckling of an ideal thinwalled elastic lining in a rigid cylindrical cavity is first presented as a simple closed form solution, and The effect of a representative small imperfection shown to be significant. The different types of imperfection that can be encountered in practical lined pipe systems are identified, and the situations in which each can arise are discussed. A generalised procedure for obtaining the structural imperfections in, and hence buckling capacities of, practical systems is then presented and two example applications are used to illustrate its application in specific situations

Effect of compaction pressure on consolidation behaviour of unsaturated silty soil

The effect of compaction pressure on subsequent soil behaviour during isotropic consolidation has been investigated by conducting controlled-suction triaxial tests on samples of an unsaturated compacted silty soil. A comprehensive set of laboratory experiments was carried out in a double-walled triaxial apparatus on samples of unsaturated soil that were prepared using two different compaction pressures. The axis translation technique was used for creating the desired suctions in the samples. In the experiments, the soil samples were subjected to isotropic consolidation under constant suctions. The results show that different compaction pressures produce different fabrics in a soil and therefore affect the behaviour of the soil. The results also show that the value of yield stress and the location of the loading¿collapse (LC) yield curve are functions of soil fabric. Furthermore, it is shown that the slopes of normal consolidation lines for densely and loosely compacted samples differ in unsaturated conditions but are the same in saturated soils. A comparison is made between the behaviour of the dense and loose samples, and the difference in the behaviour is explained

Monitoring of Rat Colonies for Antibodies to CAR Bacillus

The cilia associated respiratory (CAR) bacillus is a respiratory pathogenic bacterium of rats and other species of animal. We determined by enzymelinked immunosorbent assay (ELISA) antibudies t0 CAR bacillus antigen in sera from 20 colonies of rats. Six out of 10 Mycoplasma pulmoms ELISA positive experimental colonies contained CAR bacillus seropositive rats, comprising 26 out of 45 (58 %) samples. CAR bacillus infection was not diagnosed by ELISA in 183 samples from 10 M. pulmonis free SPF-rat breeding colonies

Promise and pitfalls in the application of big data to occupational and environmental health

EditorialIs “big data” merely a catchphrase, or does the approach hold real promise in informing occupational and environmental health? Can challenges related to messy and unrepresentative data and spurious findings be overcome

Most European SPF ‘pasteurella free’ guineapig colonies are Hacmophilus spp antibody positive

During 1993 - 1998 we tested sera of ´'pasteurella free’ guineapigs from 14 SPF breeding units of 8 European breeders by ELISA using whole cell antigens of 4 growth factor independent Pasteurellaceae (Actinoburi/lus-like taxon 5. P. mulluctda, P. pneumatmpica and SP group pasteurella) and 2 V - factor requiring Pasteurellaceae (Haemophilus Sp). Seropositiye guineapigs were detected in all 14 breeding units. The ELISAS performed with Haemophilus antigens detected significantly more positive samples than ELISAs done with non-Haemophihts antigens. In most units Showmg antibody activity against more than one Pasteurellaeeae antigen, median antibody levels detected by Huemophi/ux ELISAS were significantly higher than levels measured by the other assays. In 4 colonies also examined by culture the serological findings were confirmed by growth of Haemophims Sp, but growth factor independent Pasteurellaceae were not detected. Our findings indicate that Eurupeun ‘pasteurella free’ guineapig breeding colonies are very likely infected by V—faetor dependent Pasteurellaeeae (Haemopltilus Sp)

The adrenocortical response to synthetic ACTH following a trek to high altitude

Background: Gradual ascent to high altitude is typically associated with reduced resting aldosterone and unchanged cortisol, features that may facilitate acclimatization but are poorly understood. Aims: To investigate the cortisol and aldosterone response to adrenocorticotrophic hormone at altitude. Methods: Eleven subjects underwent a 250 µg short synacthen test at sea-level and again after trekking to 3600 m in Nepal. Cortisol and aldosterone were measured by conventional assay from blood samples taken immediately prior to the administration of synacthen (T0) and then 30 (T30) and 60 (T60) minutes later. Results: At 3600 m resting basal cortisol and aldosterone levels were both significantly lower than they were at sea-level (p=0.004, p=0.003 respectively). Cortisol values at T30 and T60 were no different between sea-level and 3600 m but the increment after synacthen was significantly (p=0.041) greater at 3600 m due to a lower basal value. Aldosterone at T30 and T60 was significantly lower (p=0.003 for both) at 3600 m than at sea-level and the increment following synacthen was also significantly (p=0.003) less at 3600 m. Conclusions: At 3600 m there appears to be a divergent adrenal response to synthetic adrenocorticotrophic hormone with an intact cortisol response but a reduced aldosterone response, relative to sea-level. This may reflect a specific effect of hypoxia on aldosterone synthesis and may be beneficial to acclimatization

Goals and outcomes of hospitalised older people:does the current hospital care match the needs of older people?

Background Due to the rising number of acutely hospitalised older people in the coming years, there is increased interest in tailoring care to the individual goals and preferences of patients in order to reach patient-centred care. Aims To investigate the goals of older hospitalised patients and the extent to which these goals were reached during hospitalisation. Methods A single-centre prospective cohort study was performed in The Netherlands between December 2017 and January 2018. Participants aged 70 years or older were included. In the first 3 days of hospitalisation, a semi-structured interview was conducted to assess the patient goals regarding the hospital admission. At 1-2 weeks after discharge, patients were asked to what extent the recent hospitalisation had contributed to reaching their goals. Results One hundred and four patients were included and follow up was completed for 86 patients. The main goals reported at hospital admission were 'remaining alive' (72.1%), 'feeling better' (71.2%) and 'improving condition' (65.4%). Hospitalisation seemed to have a positive contribution to reaching the goals 'remaining alive', 'knowing what is wrong', 'feeling better', 'reducing pain' and 'controlling disease'. Hospitalisation seemed to contribute little to reaching the goals in the categories 'enjoying life', 'independency and freedom', 'improving daily functioning', 'hobbies and work' and 'social functioning'. Conclusions It is important for healthcare professionals to know the goals of their patients. The majority of these goals were not achieved at hospital discharge. It is important to be aware of this, so sufficient aftercare can be arranged and patients can be prepared

Supporting employees with chronic conditions to stay at work:perspectives of occupational health professionals and organizational representatives

Contains fulltext : 231735.pdf (publisher's version ) (Open Access)Background: Supporting employees with chronic conditions can prevent work-related problems and facilitate sustainable employment. Various stakeholders are involved in providing support to these employees. Understanding their current practices and experienced barriers is useful for the development of an organizational-level intervention to improve this support. The aim of this study was to explore the current practices of occupational physicians and organizational representatives, identifying both barriers to providing support and opportunities for improvement. Methods: Two focus groups with sixteen occupational physicians and seven semi-structured interviews with organizational representatives were held between January and June 2018. Data was analyzed using thematic content analysis. Results: Several barriers to offer support were identified, including barriers at the organizational level (negative organizational attitudes towards employees with chronic conditions), the employee level (employees' reluctance to collaborate with employers in dealing with work-related problems), and in the collaboration between occupational physicians and organizational representatives. In addition, barriers in occupational health care were described, e.g. occupational physicians' lack of visibility and a lack of utilization of occupational physicians' support. Opportunities to optimize support included a shared responsibility of all stakeholders involved, actively anchoring prevention of work-related problems in policy and practice and a more pronounced role of the health care sector in preventing work-related problems. Conclusions: Preventing work-related problems for employees with chronic conditions can be achieved by addressing the identified barriers to provide support. In addition, both occupational physicians and organizational representatives should initiate and secure preventive support at the organizational level and in occupational health care. These insights are helpful in developing an intervention aimed at supporting employees with chronic conditions to stay at work.13 p