A Parametric Study of the Impacts of Pitched Roofs on Flow and Pollution Dispersion in Street Canyons

This study uses Computational Fluid Dynamics (CFD) to simulate flow and pollutant dispersion in a regular urban structure that consists of six equally spaced street canyons with a centred test street. This structure is known to be adverse for local ventilation and pollutant removal. The impacts of pitch rise and roof arrangement on the flow and dispersion in the test street are studied parametrically. The pitch rise is set in the range of 1–3m, which gives rise-to-run ratios of 2:12–6:12. Four different roof arrangements of flat and pitched roofs on the adjacent buildings of the test street are tested, to give a total of 12 case studies. The case with flat roofs on all the buildings is modelled to provide a reference for comparison. It is found that for all the studied cases, the flow in the test street canyon maintains a single vortex flow pattern. However, all the studied cases have lower velocity and TKE in the test canyon, which leads to reduced ventilation. After analysing the results of each case, we conclude that a high pitch rise and the presence of a pitched roof on the leeward building are the main contributors to this adverse effect. Owing to the lower velocity and TKE, the average pollutant concentration in the canyon is increased in each studied case. In the worst case scenario, the average pollutant concentration is increased by 19%

“Breakthrough Therapies” for Breast Cancer Metastasis.

Breast Cancer Metastasis (MBC) is an ultimate death sentence remains a challenge for clinicians worldwide.According to the Metastatic Breast Cancer (MBC) Awareness Network about 155,000 patients are living nowadays with MBC, and about 40,000 deaths are reported annually in the United States of America. About 10% of the patients visiting the clinic or appearing at the emergency sittings are diagnosed with stage IV breast cancer at the initial screening and require an urgent and effective treatment, which mainly focuses on controlling the disease and improve the quality of life. A breakthrough in the clinical trials for the treatment of breast cancer metastasis has been observed recently, most of these treatments are mainly drug therapies

Laryngeal and respiratory patterns in patients with paradoxical vocal fold motion

SummaryThe purposes of this study were to determine the differences in spirometric measures obtained from patients with endoscopically-documented paradoxical vocal fold motion (PVFM) and to compare them to a group of normal subjects without endoscopically-documented paradoxical vocal fold motion during non-provocative breathing and following speech. Thirty eight subjects with documented paradoxical vocal fold motion using transnasal flexible laryngoscopy (TFL) and no history of asthma and 21 normal subjects with documented normal breathing patterns and normal findings on endoscopy underwent flow-volume loop studies. Endoscopic judgments of vocal fold motion from three breathing conditions were made by two observers. The results of the endoscopic judgments indicate that paradoxical motion occurs whether breathing through the nose or mouth in the PVFM subjects, mainly after speaking and inhalation. In addition, the spirometry results indicated that the inspiratory measure of FIVC%, FVC% and FIV0.5/FIVC were significantly lower in the PVFM group compared to the normal subjects. The data supports the hypothesis that in patients with PVFM, inspiratory spirometric values play a role in identifying patients with PVFM. The finding of vocal fold closure following a speech utterance in the majority of the PVFM subjects but not in the normal control group warrants further investigation

Effect of fire smoke on some biochemical parameters in firefighters of Saudi Arabia

<p>Abstract</p> <p>Background</p> <p>Firefighters who are facing fires, are frequently exposed to hazardous materials including carbon monoxide, hydrogen cyanide, hydrogen chloride, benzene, sulphur dioxide, etc. This study aimed to evaluate some relevant serum biochemical and blood hematological changes in activity involved firefighters in comparison to normal subjects.</p> <p>Subjects and Methods</p> <p>Two groups of male firefighters volunteered to participate in the study. The first included 28 firefighters from Jeddah, while the second included 21 firefighters from Yanbu, with overall age ranged 20–48 years. An additional group of 23 male non-firefighters volunteered from both cities as normal control subjects, of age range 20–43 years. Blood samples were collected from all volunteer subjects and investigated for some relevant serum biochemical and blood hematological changes.</p> <p>Results</p> <p>The results obtained showed that, there were statistically significant differences in liver function, kidney function, serum lipid profile, cortisol, creatine kinase, lactate dehydrogenase, iron and its biologically active derivatives, and blood picture in firefighters as compared with the normal control group. These results indicate that, fire smoke mainly affects serum biochemical and blood hematological parameters. Such results might point out to the need for more health protective and prophylactic measures to avoid such hazardous health effects that might endanger firefighters under their highly drastic working conditions.</p> <p>Conclusion</p> <p>Besides using of personal protective equipments for firefighters to protect them against exposure to toxic materials of fire smoke, it is recommended that, firefighters must be under continuous medical follow up through a standard timetabled medical laboratory investigations to allow for early detection of any serum biochemical or blood hematological changes that might happen during their active service life and to allow for early treatment whenever necessary.</p

A parametric study of the effect of roof height and morphology on air pollution dispersion in street canyons

We investigate the effect of conventional pitched roofs on ventilation and pollution in street canyons using Computational Fluid Dynamics and a parametric approach. We studied parallel street canyons with several street morphologies, created by assigning a set of streets with pitched roofs, and varying their pitch and arrangement for three different height-to-width aspect ratios. The distribution of flow properties and pollution concentrations within the street canyons are examined and the effect of different parameter combinations is assessed. We find the relationship between these properties and the street morphology to be complex and case specific. For most morphologies, the pitched roofs lead to higher average pollution concentrations, and in some cases to pollution hotspots near emission sources especially on the leeward side. The pitched roofs are rarely beneficial to ventilation of the street canyons, but a few roof arrangements lead to reduced concentrations on the windward side. Roof slope is shown to significantly relate to both average pollution concentrations and their distribution inside the street; in some street geometries more than others. The results have implications for pedestrian and residential pollution exposure, and for conservation of building facades on historical buildings

Formant analysis in dysphonic patients and automatic Arabic digit speech recognition

<p>Abstract</p> <p>Background and objective</p> <p>There has been a growing interest in objective assessment of speech in dysphonic patients for the classification of the type and severity of voice pathologies using automatic speech recognition (ASR). The aim of this work was to study the accuracy of the conventional ASR system (with Mel frequency cepstral coefficients (MFCCs) based front end and hidden Markov model (HMM) based back end) in recognizing the speech characteristics of people with pathological voice.</p> <p>Materials and methods</p> <p>The speech samples of 62 dysphonic patients with six different types of voice disorders and 50 normal subjects were analyzed. The Arabic spoken digits were taken as an input. The distribution of the first four formants of the vowel /a/ was extracted to examine deviation of the formants from normal.</p> <p>Results</p> <p>There was 100% recognition accuracy obtained for Arabic digits spoken by normal speakers. However, there was a significant loss of accuracy in the classifications while spoken by voice disordered subjects. Moreover, no significant improvement in ASR performance was achieved after assessing a subset of the individuals with disordered voices who underwent treatment.</p> <p>Conclusion</p> <p>The results of this study revealed that the current ASR technique is not a reliable tool in recognizing the speech of dysphonic patients.</p

Modelling of street canyon geometries in CFD - A comparison with experimental results

Street canyon design lias a large effect on the microclimate conditions at street level. Yet modeling the outdoor urban environment is a significant challenge and validation with experimental flows is crucial to these efforts. A CFD model was constructed to simulate flow passing several street canyon geometries and the results were compared with those obtained from a laboratory study. The turbulence model chosen was the Re-Normalization Group (RNG) k-s model which we had found to be a suitable steady state turbulence model for this application. Different inlet boundary conditions were applied and made a comparison between a uniform velocity profile, a velocity profile characterized by a mathematic function and a velocity profile by importing measured velocities directly. The velocity profile characterized by a mathematic function was found to be slightly superior to the other two choices. The velocity fields and turbulence information of the CFD model were compared qualitatively and quantitatively with experimental results. The laboratory7 experiments were carried out in a water channel and measurements of velocity field within and above models of street canyons were obtamed through Particle Image Velocimetry (PIV). Velocity contours were found to be quite consistent inside the street canyon except the near wall regions. Turbulent level predicted by CFD was less reliable than velocity, but it was still qualitatively consistent in most regions inside street canyon. However, the turbulent level is predicted inaccurately at roof level

Development of the Arabic Voice Pathology Database and Its Evaluation by Using Speech Features and Machine Learning Algorithms

A voice disorder database is an essential element in doing research on automatic voice disorder detection and classification. Ethnicity affects the voice characteristics of a person, and so it is necessary to develop a database by collecting the voice samples of the targeted ethnic group. This will enhance the chances of arriving at a global solution for the accurate and reliable diagnosis of voice disorders by understanding the characteristics of a local group. Motivated by such idea, an Arabic voice pathology database (AVPD) is designed and developed in this study by recording three vowels, running speech, and isolated words. For each recorded samples, the perceptual severity is also provided which is a unique aspect of the AVPD. During the development of the AVPD, the shortcomings of different voice disorder databases were identified so that they could be avoided in the AVPD. In addition, the AVPD is evaluated by using six different types of speech features and four types of machine learning algorithms. The results of detection and classification of voice disorders obtained with the sustained vowel and the running speech are also compared with the results of an English-language disorder database, the Massachusetts Eye and Ear Infirmary (MEEI) database