Impact of urban form on concentration of air pollutants within street canyons at pedestrian level

Recent estimates published by WHO reported that in 2018 air pollution caused eight million premature deaths worldwide. The same report highlighted that outdoor air pollution was responsible for 4.2 million deaths. This implies that further efforts and mitigations are needed to reduce individuals’ exposure to harmful air pollutants. In this respect, governments around the world developed and published a number of air quality plans and frameworks. However, they either ignored or paid less attention to microclimate and urban form attributes and their impact on air pollution concentrations or dispersion in urban spaces, particularly within urban street canyons. Considering the above, this study postulates that there is a correlation between urban form and air quality. Therefore, the core focus of this thesis is to investigate this relationship in greater depth and to propose a set of recommendations that can create a desirable microclimate within various urban street canyons capable of mitigating air pollution concentrations and thereby reducing its negative impact on human health. This thesis employs a variety of methods, including fieldwork, computational modelling, and correlation analysis, to measure the influence of various street canyon configurations on the concentration of air pollution. The findings of this study confirmed several correlations between air pollution concentrations and urban form within street canyons. This study generated new knowledge on air pollution and microclimate behaviour within various street canyons. It provided recommendations for 30 distinct urban street canyon configurations in order to increase dispersion and protect pedestrians from harmful levels of air pollution. It also offered much needed knowledge and recommendations for urban designers and planners to consider to make informed design decisions to encourage greater dispersion of air pollution within various urban street canyons, particularly in areas with high pedestrian traffic to reduce and limit public exposure to harmful air pollution

Spring search algorithm for simultaneous placement of distributed generation and capacitors

Purpose. In this paper, for simultaneous placement of distributed generation (DG) and capacitors, a new approach based on Spring Search Algorithm (SSA), is presented. This method is contained two stages using two sensitive index Sv and Ss. Sv and Ss are calculated according to nominal voltageand network losses. In the first stage, candidate buses are determined for installation DG and capacitors according to Sv and Ss. Then in the second stage, placement and sizing of distributed generation and capacitors are specified using SSA. The spring search algorithm is among the optimization algorithms developed by the idea of laws of nature and the search factors are a set of objects. The proposed algorithm is tested on 33-bus and 69-bus radial distribution networks. The test results indicate good performance of the proposed methodЦель. В статье для одновременного размещения распределенной генерации и конденсаторов представлен новый подход, основанный на "пружинном" алгоритме поиска (Spring Search Algorithm, SSA). Данный метод состоит из двух этапов с использованием двух показателей чувствительности Sv и Ss. Показатели чувствительности Sv и Ss рассчитываются в соответствии с номинальным напряжением и потерями в сети. На первом этапе определяются шины-кандидаты для установки распределенной генерации и конденсаторов согласно Sv и Ss. Затем, на втором этапе размещение и калибровка распределенной генерации и конденсаторов выполняются с использованием алгоритма SSA. "Пружинный" алгоритм поиска входит в число алгоритмов оптимизации, разработанных на основе идей законов природы, а факторы поиска представляют собой набор объектов. Предлагаемый алгоритм тестируется на радиальных распределительных сетях с 33 и 69 шинами. Результаты тестирования показывают хорошую эффективность предложенного метода

The induction and growth of potato (Solanum tuberosum. L) microtubers (sante cultivar) in response to the different concentrations of 6-benzylaminopurine and sucrose

The effects of different concentrations of 6-benzylaminopurine (BAP) and sucrose as induction combinations on microtuber formation and the time of this process, numbers and fresh and dry weight of microtubers were investigated. A two-stage culture was used to study the effect of hormonal and sucrose treatments. In the first stage, a liquid MS medium containing 0.5 mgl-1 BAP + 0.4 mgl-1 gibberellic acid (GA3) + 20 gl-1 sucrose was used for the increase of branches. The cultures of single node were grown against white light (4000 to 5000 LUX) and on sucrose for one month. In the second stage, microtuber formation induced on fluid MS medium containing different concentrations of sucrose (30, 40, 60, 80 mgl-1) and BAP (1, 2, 5, 10 mgl-1) was used in continuous darkness. Microtuber formation was investigated within 10 weeks after induction.Key words: Potato (Solanum tuberosum L.), 6-benzylaminopurine, sucrose, microtuber formation

Video Data Compression by Progressive Iterative Approximation

In the present paper, the B-spline curve is used for reducing the entropy of video data. We consider the color or luminance variations of a spatial position in a series of frames as input data points in Euclidean space R or R3. The progressive and iterative approximation (PIA) method is a direct and intuitive way of generating curve series of high and higher fitting accuracy. The video data points are approximated using progressive and iterative approximation for least square (LSPIA) fitting. The Lossless video data compression is done through storing the B-spline curve control points (CPs) and the difference between fitted and original video data. The proposed method is applied to two classes of synthetically produced and naturally recorded video sequences and makes a reduction in the entropy of both. However, this reduction is higher for syntactically created than those naturally produced. The comparative analysis of experiments on a variety of video sequences suggests that the entropy of output video data is much less than that of input video data

Phase mixing of standing Alfven waves with shear flows in solar spicules

Alfvenic waves are thought to play an important role in coronal heating and solar wind acceleration. Here we investigate the dissipation of such waves due to phase mixing at the presence of shear flow and field in the stratified atmosphere of solar spicules. The initial flow is assumed to be directed along spicule axis and to vary linearly in the x direction and the equilibrium magnetic field is taken 2-dimensional and divergence-free. It is determined that the shear flow and field can fasten the damping of standing Alfven waves. In spite of propagating Alfven waves, standing Alfven waves in Solar spicules dissipate in a few periods. As height increases, the perturbed velocity amplitude does increase in contrast to the behavior of perturbed magnetic field. Moreover, it should be emphasized that the stratification due to gravity, shear flow and field are the facts that should be considered in MHD models in spicules.Comment: Accepted for publication in Astrophysics & Space Scienc

Two-Photon Spectroscopy of the NaLi Triplet Ground State

We employ two-photon spectroscopy to study the vibrational states of the triplet ground state potential ($a^3\Sigma^+$) of the $^{23}$Na$^{6}$Li molecule. Pairs of Na and Li atoms in an ultracold mixture are photoassociated into an excited triplet molecular state, which in turn is coupled to vibrational states of the triplet ground potential. Vibrational state binding energies, line strengths, and potential fitting parameters for the triplet ground $a^3\Sigma^+$ potential are reported. We also observe rotational splitting in the lowest vibrational state.Comment: 7 pages, 3 figure