Modelling heat transfer and respiration of occupants in indoor climate

Although the terms "Human Thermal Comfort" and "Indoor Air Quality (IAQ)" can be highly subjective, they still dictate the indoor climate design (HVAC design) of a building. In order to evaluate human thermal comfort and IAQ, one of three main tools are used, a) direct questioning the subjects about their thermal and air quality sensation (voting, sampling etc.), b) measuring the human thermal comfort by recording the physical parameters such as relative humidity, air and radiation temperature, air velocities and concentration gradients of pollutants or c) by using numerical simulations either including or excluding detailed thermo-physiological models. The application of the first two approaches can only take place in post commissioning and/or testing phases of the building. Use of numerical techniques can however be employed at any stage of the building design. With the rapid development in computational hard- and software technology, the costs involved in numerical studies has reduced compared to detailed tests. Employing numerical modelling to investigate human thermal comfort and IAQ however demand thorough verification and validation studies. Such studies are used to understand the limitations and application of numerical modelling of human thermal comfort and IAQ in indoor climates. This PhD research is an endeavour to verify, validate and apply, numerical simulation for modelling heat transfer and respiration of occupants in indoor climates. Along with the investigations concerning convective and radiation heat transfer between the occupants and their surroundings, the work focuses on detailed respiration modelling of sedentary human occupants. The objectives of the work have been to: verify the convective and radiation numerical models; validate them for buoyancy-driven flows due to human occupants in indoor climates; and apply these validated models for investigating human thermal comfort and IAQ in a real classroom for which field study data was available. On the basis of the detailed verification, validation and application studies, the findings are summarized as a set of guidelines for simulating human thermal comfort and IAQ in indoor climates. This PhD research involves the use of detailed human body geometries and postures. Modelling radiation and investigating the effect of geometrical posture has shown that the effective radiation area varies significantly with posture. The simulation results have shown that by using an effective radiation area factor of 0.725, estimated previously (Fanger, 1972) for a standing person, can lead to an underestimation of effective radiation area by 13% for the postures considered. Numerical modelling of convective heat transfer and respiration processes for sedentary manikins have shown that the SST turbulence model (Menter, 1994) with appropriate resolution of near wall region can simulate the local air velocity, temperature and heat transfer coefficients to a level of detail required for prediction of thermal comfort and IAQ. The present PhD work has shown that in a convection dominated environment, the detailed seated manikins give rise to an asymmetrical thermal plume as compared to the thermal plumes generated by simplified manikins or point sources. Validated simulation results obtained during the present PhD work have shown that simplified manikins can be used without significant limitations while investigating IAQ of complete indoor spaces. The use of simplified manikins however does not seem appropriate when simulating detailed respiration effects in the immediate vicinity of seated humans because of the underestimation in the amount of re-inhaled CO2 and pollutants from the surroundings. Furthermore, the results have shown that due to the simplification in geometrical form of the nostrils, the CO2 concentration is much higher near the face region (direct jet along the nostrils) as compared to a detailed geometry (sideways jet). Simulating the complete respiration cycle has shown that a pause between exhalation and inhalation has a significant effect on the amount of re-inhaled CO2. Previous results have shown the amount of re-inhaled CO2 to range between 10 - 19%. The present study has shown that by considering the pause, this amount of re-inhaled CO2 falls down to values lower than 1%. A comparison between the simplified and detailed geometry has shown that a simplified geometry can cause an underestimation in the amount of re-inhaled CO2 by more than 37% as compared to a detailed geometry. The major contribution to knowledge delivered by this PhD work is the provision of a validated seated computational thermal manikin. This PhD work follows a structured verification and validation approach for conducting CFD simulations to predict human thermal comfort and indoor air quality. The work demonstrates the application of the validated model to a classroom case with multiple occupancy and compares the measured results with the simulation results. The comparison of CFD results with measured data advocates the use of CFD and visualizes the importance of modelling thermal manikins in indoor HVAC design rather than designing the HVAC by considering empty spaces as the occupancy has a strong influence on the indoor air flow. This PhD work enables the indoor climate researchers and building designers to employ simplified thermal manikin to correctly predict the mean flow characteristics in indoor surroundings. The present work clearly demonstrates the limitation of the PIV measurement technique, the importance of using detailed CFD manikin geometry when investigating the phenomena of respiration in detail and the effect of thermal plume around the seated manikin. This computational thermal manikin used in this work is valid for a seated adult female geometry

Sustainable Core Earnings & Stock Performance: An Evidence of the Pharmaceutical Sector of Pakistan

  This study furnishes a new measure of earnings quality that pertains to the sustainability of core-component & non-core components of earnings measured through firms’ and industry profitability benchmark and finds its impact on the stock performance in the context of the pharmaceutical sector of Pakistan. The study identifies twelve major determinants of sustainable earnings in the firms of the pharmaceutical sector of Pakistan that are mainly classified into core and non-core earnings and sub-classified into the firms’ and industry profitability benchmark and all three profitability measures (Gross Profit, Operating Profit & Net Profit). Based upon the core and non-core earnings components, the intensity of core earnings is measured and its impact on the stock performance is analyzed. For this purpose, a balanced panel data of 09 firms of the pharmaceutical sector that are listed in Pakistan stock exchange for 10 years i.e. 2010 to 2019 is used. The study employs two estimators: one, Random Effects Model for finding the determinants of sustainable earnings and its ability of sustainability and predictability, second, dynamic GMM model for measuring the impact of sustainable earnings on stock performance. This study affirms that the earnings of the firms operating in the pharmaceutical sector are sustainable; firms’ intensity of core earnings is a significant determinant of its profitability and industry intensity of core earnings is an insignificant determinant of firms’ profitability for the firms operating in the pharmaceutical sector of Pakistan. Lastly, the study did not find any significant impact of unexpected earnings on the stock’s performance on the firms. This study is of vital interest to investors, auditors, analysts, educational institutes, researchers and regulators

Impact of diabetes mellitus on nerves

Background: Involvement of the peripheral and autonomic nervous systems is probably the most common complication of diabetes. The main symptoms of diabetic polyneuropathy include negative symptoms (those related to nerve fiber loss or dysfunction) such as numbness and weakness, and positive symptoms (those related to abnormal function of surviving nerve fibers) such as tingling and pain.Methods: This was a cross-sectional study held in diabetic clinic of Nishter hospital, Multan, Pakistan. The study included any diabetic patients showing symptoms of neuropathy.Results: There were total of 140 in this study. This study included 85% of male and 15% of female. Most common symptoms of diabetic neuropathy were pain (70%) and tingling (70%) followed by numbness in 65% of patients. There were 28 patients in 5 years duration of diabetes, 35 people in 6-10 years duration, 21 patients in 11-15 years duration, and 14 patients in 20+ years duration.Conclusions: Neuropathy due to diabetes is crippling especially when pain is the prominent symptoms. Autonomic symptoms like constipation and lightheadedness are discomforting for the patients. The most commonly used screening test is vibrating tuning fork test which is east to perform is clinical setting and is not time consuming. Diabetic patients need to take special care of

Coupling a model of human thermoregulation with computational fluid dynamics for predicting human-environment interaction

This paper describes the methods developed to couple a commercial CFD program with a multi-segmented model of human thermal comfort and physiology. A CFD model is able to predict detailed temperatures and velocities of airflow around a human body, whilst a thermal comfort model is able to predict the response of a human to the environment surrounding it. By coupling the two models and exchanging information about the heat transfer at the body surface the coupled system can potentially predict the response of a human body to detailed local environmental conditions. This paper presents a method of exchanging data, using shared files, to provide a means of dynamically exchanging simulation data with the IESD-Fiala model during the CFD solution process. Additional code is used to set boundary conditions for the CFD simulation at the body surface as determined by the IESD-Fiala model and to return information about local environmental conditions adjacent to the body surface as determined by the CFD simulation. The coupled system is used to model a human subject in a naturally ventilated environment. The resulting ventilation flow pattern agrees well with other numerical and experimental work

A2ML1 and otitis media : novel variants, differential expression, and relevant pathways

A genetic basis for otitis media is established, however, the role of rare variants in disease etiology is largely unknown. Previously a duplication variant within A2ML1 was identified as a significant risk factor for otitis media in an indigenous Filipino population and in US children. In this report exome and Sanger sequencing was performed using DNA samples from the indigenous Filipino population, Filipino cochlear implantees, US probands, Finnish, and Pakistani families with otitis media. Sixteen novel, damaging A2ML1 variants identified in otitis media patients were rare or low-frequency in population-matched controls. In the indigenous population, both gingivitis and A2ML1 variants including the known duplication variant and the novel splice variant c.4061 + 1 G>C were independently associated with otitis media. Sequencing of salivary RNA samples from indigenous Filipinos demonstrated lower A2ML1 expression according to the carriage of A2ML1 variants. Sequencing of additional salivary RNA samples from US patients with otitis media revealed differentially expressed genes that are highly correlated with A2ML1 expression levels. In particular, RND3 is upregulated in both A2ML1 variant carriers and high-A2ML1 expressors. These findings support a role for A2ML1 in keratinocyte differentiation within the middle ear as part of otitis media pathology and the potential application of ROCK inhibition in otitis media.Peer reviewe

Implementation and Simulation Study of 802.11b-Based Multi Rate WLAN and Ad Hoc Networks

Abstract The focus of this project will be on studying the behaviour of throughput changes of the cell when nodes send their data in different bit rate. The main goal of this thesis was to develop techniques and tools that can cope with multiple data rate, behaviour. The project involved the following goals: · Gain a deeper understanding of how 802.11/802.11b works both at the PHY and MAC Layer. · Implementation of 802.11b extension in NS-2. · Simulate maximum achievable throughput for one single UDP session · Analyse throughput, delay and jitter of a station with mobility. · Analyse throughput, delay and jitter of a station with mobility and pause time. · Analyse throughput, delay and jitter of one-hop behaviour where stations in a cell send their data with different bit rate. · Analyse throughput, delay and jitter of two-hop and three-hop behaviour where stations in a cell send their data with different bit rate. After conducting throughput analysis on simulation it is found that the throughput obtained by wireless node is much smaller then the nominal bit rate of 11 Mbps. Co-existence between the fast and slow host in the radio channel decreases the performance of fast host considerably. The main reason for this is the basic CSMA/CA protocol. This access method guarantees that the long-term probability for accessing the channel is equal for all hosts, so when a slow host takes control of the medium for long time it penalizes the fast transmitting host. Furthermore if RTS-CTS mechanism is used it imposes additional delay as these packets are exchanged before any data packets are sent. In the case when there are flows with multi-hop, additional delay will be imposed and the packet drops in the intermediate nodes. This can stem from packet collisions or buffer overflows. However when there are multi-hop flows concurrently with on-hop flows sending at same data rate considerable decrease in throughput for one-hop flow will happen. In the case when there is different and lower data rate for multi-hop flow, it happens that in period the fast host captures the channel leading to starvation for the slower-flows

DNBs transformation journey from bank to technology player - A case study of innovation capabilities in DNB

Master in Business Administration (MBA) - Nord universitet 2019Sperret til 2022-12-1

Urgent need for the introduction of Tenecteplase in Pakistan: A Call to action for improved stroke and Mi Care

Madam, Tenecteplase is a recombinant tissue plasminogen activator (tPA) that is used in many countries worldwide for reperfusion in acute ischemic stroke (AIS) and STEMI because of its longer half-life and high fibrin specificity compared to other tPAs (e.g., alteplase) and Streptokinase.1 Tenecteplase binds with fibrin-rich clots using its fibronectin finger-like and kringle-2 domains. The binding allows the protease domain to cleave the Arg/Val bond, converting plasminogen into plasmin, which breaks the fibrin matrix of the thrombus, resulting in clot dissolution. While Stroke and MI remain in the top 5 leading causes of death in Pakistan2, this highly efficient thrombolytic agent is not yet accessible in most hospitals for reperfusion in acute ischemic stroke and myocardial infarction cases. Many studies offer promising results, with tenecteplase being a better thrombolytic agent for acute ischemic stroke and STEMI than alteplase. In India, studies declare tenecteplase effective and safe in STEMI patients with clinically successful thrombolysis reported in 80.67% of patients, while intracranial hemorrhage associated with tenecteplase was only 0.39%.3 Tenecteplase is more efficient and at least as safe as alteplase for acute ischemic stroke. According to a meta-analysis involving 2031 patients, the patients given Tenecteplase showed higher recanalization rates (ARD=0.11, 95%CI) and early neurological improvement (ARD=0.10, 95% CI) compared to patients given alteplase.4 Tenecteplase also has a lower cost and a more favorable pharmacokinetic profile allowing bolus injection. Regrettably, Tenecteplase is not yet accessible in Pakistan due to unclear political and administrative factors, and border restrictions. Studies claim that only six hospitals in Pakistan currently offer intravenous thrombolytic therapy with alteplase, all being private tertiary care hospitals.5 While the world is adopting Tenecteplase instead of alteplase because of its better results, a more favourable side effects profile, and lower cost, our healthcare system is still dependent on SK for IV thrombolysis in cases of STEMI, which too is sometimes not available in many hospitals. In light of available evidence suggesting Tenecteplase as a better alternative to alteplase and Streptokinase, the health government and hospital policymakers should consider introducing tenecteplase in Pakistan as the standard care for STEMI, New Onset LBBB (Left Bundle Branch Block), Acute Ischemic Stroke, Prosthetic Valve Thrombosis, Pulmonary Embolism, and Deep Venous Thrombosis