1,126 research outputs found
A holistic analysis method to assess the controllability of commercial buildings and their systems
This paper describes a novel design process for advanced MIMO (multiple inputs and multiple outputs) control system design and simulation for buildings. The paper describes the knowledge transfer from high technology disciplines such as aerospace flight control systems and the space industry to establish a three-step modelling and design process. In step 1, simplified, but holistic nonlinear and linearised dynamic models of the building and its systems is derived. This model is used to analyse the controllability of the building. In step 2, further synthesis of this model leads to the correct topology of the control system design. This is proved through the use of simulation using the simple building model. In step 3, the controller design is proved using a fully detailed building simulation such as ESP-r that acts as a type of virtual prototype of the building. The conclusions show that this design approach can help in the design of superior and more complex control systems especially for buildings designed with a Climate Adaptive Building (CAB) philosophy where many control inputs and outputs are used to control the building's temperature, concentration of CO2, humidity and lighting levels
Effectiveness of Pulmonary Rehabilitation in Patients with COPD
Background: Pulmonary rehabilitation (PR) is beneficial for patients with COPD, with improvement in exercise capacity and health-related quality of life. Despite these overall benefits, the responses to PR vary significantly among different individuals. It is not clear if PR is beneficial for patients with COPD and normal exercise capacity. Although it is believed that longer pulmonary rehabilitation programs can provide better results, most of the evidence comes from short-term programs.
Objective: The objective of this analysis was to determine the effectiveness of respiratory services provided in the hospital or community by respiratory therapists (RTs) in reducing health care utilization and improving patient outcomes. The aim was to evaluate the outcomes of a comprehensive pulmonary rehabilitation (PR) in chronic obstructive pulmonary disease.
Methodology: All 65 Pakistani patients who met the inclusion criteria with ages between 40 to 65 years, including both male and female, with mild to severe COPD were enrolled in the study on the basis of convenient sampling. Informed consent was taken from each patient starting about the study and their rights to withdraw from study. A demographics detail (name, age, sex) was noted along with the necessary medical history. A questionnaire was made to see the effects of pulmonary rehabilitation in patients with COPD. All necessary tests were performed to evaluate the patient betterment completely.
Results: The mean FEV1 in the subjects was 1.29 ± 0.47 L/min, 64.8 ± 23.0% of predicted. Clinically there is a little effect on CXR pattern, FEV1 and FEV1/FVC after pulmonary rehabilitation. But overall quality of life improved after pulmonary rehabilitation. Mainly improvement occurs in peak expiratory flow rate, BORG dyspnea scale, 6 mint walk test distance (meters) and Oxygen saturation after rehabilitation.
Conclusion: These results showed that patients with COPD had benefited from a comprehensive PR program in an out-patient setting regardless of disease severity. Exercise training can result in significant improvement in health-related quality of life, exercise capacity, respiratory muscle strength, and exertional dyspnea in subjects with COPD and normal exercise capacity
Compression properties of polymeric syntactic foam composites under cyclic loading
Syntactic foams are composite materials frequently used in applications
requiring the properties of low density and high damage tolerance. In the
present work, polymer-based syntactic foams were studied under cyclic
compression in order to investigate their compressibility, recoverability,
energy dissipation and damage tolerance. These syntactic foams were
manufactured by adding hollow polymer microspheres of various sizes and wall
thicknesses into a polyurethane matrix. The associated loading and unloading
curves during cyclic testing were recorded, revealing the viscoelastic nature
of the materials. SEM images of the samples were obtained in order to study
potential damage mechanisms during compression. It was observed that these
syntactic foams exhibit high elastic recovery and energy dissipation over a
wide range of compressional strains and the addition of polymer microspheres
mitigate the damage under compressional loading.Comment: 25 pages, 13 figure
Waterlogging and salinity management in the Sindh Province. Volume 1 - The irrigated landscape: resource availability across the hydrological divides
Irrigation management / River basins / Irrigated farming / Climate / Irrigation systems / Irrigation canals / Discharges / Water balance / Waterlogging / Salinity / Groundwater development / Tube wells / Water table / Drainage / Public sector / Land reclamation / Pakistan / Sindh Province / Indus Basin / Rohri / Larkana / Shikarpur / Hairdin / North Dadu / Ghotki / East Khairpur / Sukkur Barrage
Supernova remnants and gamma-ray sources
A review of the possible relationship between gamma-ray sources and supernova
remnants (SNRs) is presented. Particular emphasis is given to the analysis of
the observational status of the problem of cosmic ray acceleration at SNR shock
fronts. All positional coincidences between SNRs and unidentified gamma-ray
sources listed in the Third EGRET Catalog at low Galactic latitudes are
discussed on a case by case basis. For several coincidences of particular
interest, new CO(J=1-0) and radio continuum maps are shown, and the mass
content of the SNR surroundings is determined. The contribution to the
gamma-ray flux observed that might come from cosmic ray particles (particularly
nuclei) locally accelerated at the SNR shock fronts is evaluated. We discuss
the prospects for future research in this field and remark on the possibilities
for observations with forthcoming gamma-ray instruments.Comment: Final version of a review article, to appear in the Physics Reports
(82 pages, 31 figures). Figures requiring high quality are just too large and
too many to be included here. Please download them from
http://www.angelfire.com/id/dtorres/down3.htm
Investigation of vibrations at the skin surface caused by the flow disturbance in stenosed tubes
An occlusion in an artery (a stenosis) induces disturbances in the downstream flow and those disturbances produce mechanical waves that impinge on the vessel wall causing it to vibrate. These vibrations then travel through the soft tissues to the skin surface where they can be detected, thus providing a possible method for the non-invasive diagnosis of the underlying disease. Hence, in this study, the potential of measuring those disturbances was explored. Experiments were set-up to model the behaviour of carotid artery under different con-ditions. A 40:60 (by volume) glycerine-water solution was selected to simulate the vis-cosity of blood (approximately 4cP). A thin walled (250 μm - 350μm wall thickness) latex Penrose drain tube, with an external diameter of 6.35mm and a Young’s Modulus value of around 0.9MPa (for circumferential strains between 0.08 - 0.10), was used to mimic the carotid artery. Different severities (60%, 75% and 90% area reduction) of the stenoses, with a circular cross-section, were investigated. Two different types, axisym-metric and non-axisymmetric, were investigated to study the effects of asymmetry in the stenoses. The stenoses were 3D printed in an opaque VeroWhite material to mimic the occlusion. The stenosed artery was then embedded into a standardised neck phantom (filled with Parker Aquasonic 100 ultrasound gel) to mimic the soft tissues and the top of the phantom was sealed with a thin (50μm) polyurethane film (Platilon), with a stiffness value of approximately 21MPa, to simulate the skin. To detect the disturbance on the phantom surface, different equipment (including ac-celerometers, and a Laser Doppler Vibrometer [LDV]) were tested. The LDV proved to be the most reliable under all conditions and was chosen as the standard measurement method for all the phantom experiments. Having selected the appropriate materials and measurement techniques, the effects of flow rate, stenosis severity, stenosis symmetry and fluid viscosity were investigated. Both, steady and pulsatile flows were perfused through the phantom with flows ranging from 0-450ml/min for steady flow and 308-340ml/min for pulsatile flow. On modifying the viscosity of the fluid, it was seen that increasing the viscosity reduced the perturbations in the flow. This was expected due to the increased viscous forces in the flow, as the viscosity of the fluid increased. Furthermore, the experiments showed that, on increasing the flow rate, the stenosis severity, and/or introducing asymmetry in the stenosis, the post-stenotic perturbations in the flow were amplified and their zone of origin moved nearer to the stenosis. These features were confirmed by conducting bare tube experiments as well as some ultrasound scans in a modified phantom. On further investigation it was found that along with the positional dependence of these perturbations, their range of frequencies was increased with increasing flow rate, stenosis severity and/or stenosis asymmetry. In the phantom experiments the disturbances were barely detectable for an area reduc-tion of 60% and were weakly present at 75%. However, strong disturbances were seen for the highly (90%) stenosed tube. A possible cause of the unexpectedly small effect of the 75% stenosis was speculated to be the stenosis symmetry: in-vivo, atherosclerotic plaques are invariably not symmetrical. To show this, experiments were conducted with an asymmetric stenosis where higher level of disturbances were detected (even with the 75% stenosis severity), hence, emphasising the impact of stenosis symmetry. A preliminary computational simulation was also set-up to allow for future detailed modelling of the effects of changing the physical conditions on the signals arriving at the skin. The simulations (whose accuracy yet remains to be validated) showed similar effects of the increasing flow rates and the stenosis severity as the disturbances were amplified and moved nearer to the stenosis on increasing the value of either variable. Following this, an attempt was made to develop a fluid-structure interaction model to simulate the neck phantom and a sample simulation was set-up. This study developed a novel method for detecting the disturbances in the post-stenotic region, and the experimental results from this study suggest the feasibility of using LVD to infer the presence of a stenosis at an early stage before the symptoms are evident
Accurate <i>ab initio</i> ro-vibronic spectroscopy of the X<sup>2</sup>∏ CCN radical using explicitly correlated methods
Explicitly correlated CCSD(T)-F12b calculations have been carried out with systematic sequences of correlation consistent basis sets to determine accurate near-equilibrium potential energy surfaces for the X<sup>2</sup>∏ and a<sup>4</sup>Σ<sup>−</sup> electronic states of the CCN radical. After including contributions due to core correlation, scalar relativity, and higher order electron correlation effects, the latter utilizing large-scale multireference configuration interaction calculations, the resulting surfaces were employed in variational calculations of the ro-vibronic spectra. These calculations also included the use of accurate spin-orbit and dipole moment matrix elements. The resulting ro-vibronic transition energies, including the Renner-Teller sub-bands involving the bending mode, agree with the available experimental data to within 3 cm<sup>−1</sup> in all cases. Full sets of spectroscopic constants are reported using the usual second-order perturbation theory expressions. Integrated absorption intensities are given for a number of selected vibronic band origins. A computational procedure similar to that used in the determination of the potential energy functions was also utilized to predict the formation enthalpy of CCN, ΔH<sub>f</sub>(0K) = 161.7 ± 0.5 kcal/mol
A randomised controlled trial of a brief cognitive behavioural intervention for men who have hot flushes following prostate cancer treatment (MANCAN)
OBJECTIVE: Hot flushes and night sweats (HFNS) are experienced by up to 80% of prostate cancer patients undergoing androgen deprivation therapy (ADT). This study evaluates the effects of a guided self-help cognitive behavioural therapy (CBT) intervention on HFNS problem-rating (primary outcome), HFNS frequency, mood and health-related quality of life (secondary outcomes) in patients undergoing ADT. METHODS: Patients reporting treatment-induced HFNS were randomly assigned to CBT (n = 33) or treatment as usual (TAU) (n = 35), stratified for cancer type. The CBT intervention included a booklet, CD plus telephone contact during a 4-week period. Validated self-report questionnaires were completed at baseline, 6 weeks and 32 weeks after randomisation. The primary outcome was HFNS problem rating (perceived burden of HFNS) at 6 weeks after randomisation. Potential moderators and mediators were examined. Data analysis was conducted on a modified intention-to-treat basis. RESULTS: Compared with TAU, CBT significantly reduced HFNS problem rating (adjusted mean difference: -1.33, 95% CI -2.07 to -0.58; p = 0.001) and HFNS frequency (-12.12, 95% CI -22.39 to -1.84; p = 0.02) at 6 weeks. Improvements were maintained at 32 weeks, but group differences did not reach significance. There were significant reductions in negative HFNS Beliefs and Behaviours following CBT, but not in mood or quality of life. CONCLUSIONS: Guided self-help CBT appears to be a safe and effective brief treatment for men who have problematic HFNS following prostate cancer treatments. Further research might test the efficacy of the intervention in a multicentre trial
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