scholarly journals Dampak Pelaksanaan Pembatasan Sosial Berskala Besar (PSBB) Terhadap Konsentrasi PM10 di Pekanbaru

Jurnal Ecolab ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 13-22
Author(s):  
rosita rakhim ◽  
Keyword(s):  
Polar Plot

Dampak Pelaksanaan Pembatasan Sosial Berskala Besar (PSBB) Terhadap Konsentrasi PM10 di Pekanbaru. Salah satu faktor penurunan kualitas udara dapat disebabkan oleh aktivitas manusia. Penetapan Pembatasan Sosial Berskala Besar (PSBB) karena pandemi Covid-19 mengakibatkan penurunan aktivitas masyarakat diluar ruangan. Tujuan penelitian ini adalah membandingkan kondisi kualitas udara di Pekanbaru sebelum dan saat diterapkan PSBB. Data yang digunakan adalah data konsentrasi PM10 hasil pengukuran PM10 Analyzer, BAM1020. Statistik deskriptif dan uji Mann-Whitney U test sebagai uji non-parametrik untuk menentukan perubahan signifikansi dari PM10 sebelum dan saat PSSB. Hasil penelitian menunjukkan bahwa sebelum dan saat PSBB, konsentrasi PM10 di Pekanbaru berada dalam kategori baik (0-50 µg/m3). Berdasarkan distribusi frekuensi kondisi sebelum PSBB, konsentrasi PM10 lebih tinggi jika dibandingkan saat kondisi PSBB. Kemudian berdasarkan polar plot sebaran konsentrasi PM10 bervariasi dengan konsentrasi terbesar sebelum PSBB yaitu antara 12-14 µg/m3 pada arah Barat Laut, sedangkan untuk kondisi saat PSBB konsentrasi terbesar antara 9-10 µg/m3 pada arah Timur Laut. Berdasarkan rata-rata periode waktu per jam dan harian menunjukkan bahwa konsentrasi PM10 cenderung lebih tinggi saat malam hari dibandingkan siang hari dan konsentrasi PM10 tertinggi terjadi pada hari Selasa dan terendah pada hari Minggu. Hasil Uji Mann-Whitney menunjukkan ada perubahan yang signifikan dalam konsentrasi PM10 sebelum dan saat PSBB di Pekanbaru.

scholarly journals Analysis of Segmental Strain for the Detection of Chronic Ischemic Scars in Non-Contrast Cardiac MRI Cine Images: A Feasibility Study

2020 ◽  
Author(s):  
Malgorzata Polacin ◽  
Mihaly Karolyi ◽  
Matthias Eberhard ◽  
Alexander Gotschy ◽  
Bettina Baessler ◽  
...  
Keyword(s):  
Wall Motion ◽  
Circumferential Strain ◽  
Radial Strain ◽  
Scar Tissue ◽  
Remote Myocardium ◽  
Healthy Individuals ◽  
Polar Plot ◽  
Global Strain ◽  
Motion Assessment ◽  
Global Peak

Abstract Aims Cardiac magnetic resonance imaging (MRI) with late gadolinium enhancement (LGE) is considered the gold standard for scar detection after myocardial infarction. In times of increasing skepticism about gadolinium depositions in brain tissue and contraindications of gadolinium administration in some patient groups, tissue strain-based techniques for detecting ischemic scars should be further developed as part of clinical protocols. Therefore, the objective of the present work was to investigate the feasibility of scar detection in segmental strain calculations based on routinely acquired non-contrast cine images in patients with chronic infarcts.Methods Forty-six patients with chronic infarcts and scar tissue in LGE images (5 female, mean age 52 ± 19 years) and 24 gender- and age- matched healthy controls (2 female, mean age 47 ± 13 years) were included. Global (global peak circumferential [GPCS], global peak longitudinal [GPLS], global peak radial strain [GPRS]) and segmental (segmental peak circumferential [SPCS], segmental peak longitudinal [SPLS], segmental peak radial strain [SPRS]) strain parameters were calculated from standard balanced SSFP cine sequences using commercially available software (Segment CMR, Medviso, Sweden). Two independent blinded readers localized potentially infarcted segments in segmental circumferential strain calculations (endo-/epicardially contoured short axis cine and resulting polar plot strain map) and by visual wall motion assessment of cine images. Results Global strain values were reduced in patients compared to controls (GPCS p= 0.02; GPLS p= 0.04; GPRS p= 0.01). Patients with preserved ejection fraction showed also reduced GPCS compared to healthy individuals (p=0.04). In patients, mean SPCS was significantly impaired in subendocardially (- 5,4% +/- 2) and in transmurally infarcted segments (- 1,2% ± 3) compared to remote myocardium (-12,9% +/- 3, p= 0.02 and 0.03, respectively). ROC analysis revealed an optimal cut- off value for SPCS for discriminating infarcted from remote myocardium of - 7,2 % with a sensitivity of 89,4 % and specificity of 85,7%. Mean SPRS was impeded in transmurally infarcted segments (15,9 % +/- 6) compared to SPRS of remote myocardium (31,4% +/- 5; p= 0.02). The optimal cut-off value for SPRS for discriminating scar tissue from remote myocardium was 16,6% with a sensitivity of 83,3% and specificity of 76,5%. 80.3 % of all in LGE infarcted segments (118/147) were correctly localized in segmental circumferential strain calculations based on non-contrast cine images compared to 53.7% (79/147) of infarcted segments detected by visual wall motion assessment (p > 0.01). Conclusion Global strain parameters are impaired in patients with chronic infarcts compared to healthy individuals. Mean SPCS and SPRS in scar tissue is impeded compared to remote myocardium in infarcts patients. Blinded to LGE images, two readers correctly localized 80% of infarcted segments in segmental circumferential strain calculations based on non-contrast cine images, in contrast to only 54% of infarcted segments detected by visual wall motion assessment. Analysis of segmental circumferential strain shows a promising alternative for scar detection based on routinely acquired, non-contrast cine images for patients who cannot receive or decline gadolinium.

scholarly journals Comparison of surgically induced astigmatism between anterior and total cornea in 2.2 mm steep meridian incision cataract surgery

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Young-chae Yoon ◽  
Minji Ha ◽  
Woong-Joo Whang
Keyword(s):  
Cataract Surgery ◽  
Intraocular Lens ◽  
Corneal Surface ◽  
Polar Plot ◽  
Mean Values ◽  
Surgically Induced Astigmatism ◽  
Induced Astigmatism ◽  
The Mean ◽  
Surgically Induced ◽  
Corneal Refractive Power

Abstract Background This study aimed to compare surgically induced astigmatism (SIA) on the anterior and total cornea during cataract surgery through a 2.2 mm steep meridian incision. Methods The study included 69 left eyes of 69 patients who had undergone cataract surgery. The 69 eyes were classified into three subgroups according to the preoperative steep meridian. Following phacoemulsification, an intraocular lens was inserted into the bag. The keratometric measurements were taken 12 months postoperatively, on the anterior cornea (automated keratometer and anterior keratometry [K] from a rotating Scheimpflug camera) and total cornea (equivalent K reading [EKR] 3.0 mm, EKR 4.5 mm, total corneal refractive power (TCRP) 2.0 mm ring, TCRP 3.0 mm zone, TCRP 4.0 mm zone). The SIA was analyzed for each parameter. Results On the double-angle polar plot, the summated vector mean values of SIA determined by the automated keratometer and Scheimpflug anterior K were 0.28 diopter (axis: 177°) and 0.37 diopter (axis: 175°) in with-the-rule (WTR) astigmatism; 0.03 diopter (axis: 156°) and 0.18 diopter (axis: 177°) in oblique astigmatism; 0.15 diopter (axis: 96°) and 0.17 diopter (axis: 73°) in against-the-rule (ATR) astigmatism. The mean SIAs on the total cornea ranged from 0.31 to 0.42 diopter in WTR astigmatism; from 0.16 to 0.27 diopter in oblique astigmatism; from 0.04 to 0.11 diopter in ATR astigmatism. Mean magnitude SIA ranged from 0.41 to 0.46 diopter on anterior corneal surface and 0.50 to 0.62 diopter on total cornea. J0 and J45 of the posterior cornea showed no significant changes after cataract surgery, and the changes in J0 and J45 did not show any statistical differences between the anterior and total cornea (all p > 0.05). Conclusions There were no differences in the summed vector mean values of SIA between the anterior cornea and the total cornea.

scholarly journals Avaliação da Acurácia do Produto de Altimetria do Laboratório de Agricultura e Floresta (Evaluation of the Accuracy of the Product of Altimetry of the laboratory of Agriculture and Forest)

2014 ◽  
Vol 7 (4) ◽  
pp. 702
Author(s):  
João Mauricio Batista Filho ◽  
Arcilan Trevenzoli Assire ◽  
Egidio Arai ◽  
Nívea Adriana Dias Pons ◽  
Ramon Freitas
Keyword(s):  
Global Positioning System ◽  
Ground Truth ◽  
Base Station ◽  
Virtual Laboratory ◽  
Regional Studies ◽  
Polar Plot ◽  
Thematic Map ◽  
Verification Methods ◽  
Global Positioning ◽  
Scientific Project

Os dados do Shuttle Radar Thematic Map (SRTM) vêm sendo amplamente utilizados para aplicações em geomorfologia, topografia, estimativas de Tsunami e estudos urbanos, dentre outros. Recentemente, um projeto científico (http://www.dsr.inpe.br/laf/canasat) desenvolveu um aplicativo livre e amigável para visualização instantânea da elevação local dentro do conceito de laboratórios virtuais. Esta ferramenta, chamada de Laboratório de Agricultura e Floresta (LAF) permite estimativas da anisotropia da elevação em torno de um ponto geográfico selecionado. A visualização da anisotropia baseia-se em um gráfico polar de elevação em torno de dois círculos concêntricos, e permite uma visualização rápida da topografia em torno do ponto selecionado. Entretanto, o estudo sobre a confiabilidade deste produto exige verificações quanto a sua acurácia por comparações com medições de alta precisão, como o Sistema Diferencial de Posicionamento Global (DGPS). Neste trabalho é apresentado um estudo baseado em dados representativos e considerados verdade de campo, levantado a partir de DGPS, em uma região de relevo complexo no município de Itajubá (MG). Os resultados indicam e eficiência da ferramenta, mas apontam alguns cuidados necessários para a utilização acurada da mesma.    A B S T R A C T Since Shuttle Radar Thematic Map (SRTM) data became available, many studies utilized them for applications in geomorphology, topography, vegetation cover studies, tsunami assessment, and urban studies, among others. Recently, a scientific project (http://www.dsr.inpe.br/laf/canasat) engendered on Brazilian National Institute for Space Research, developed a free and friendly tool for instantaneous visualization of local elevation within the concept of a virtual laboratory framework. This tool, named Laboratory of Agriculture and Forest, was build to assess the elevation anisotropy around selected points. The anisotropy visualization is a simple polar plot of elevation around two simple circles, allowing a rapid view of the topography around the selected point. This tool allows interactivity and provides a range of distance between the center of the selected coordinate and the sampled circles. However, overall assessment of the accuracy of this product requires additional regional studies involving accuracy verification methods with higher level of precision, such as the Differential Global Positioning System (DGPS). The study presented in this paper is based on ground truth control collected with DGPS system, with differential base station data, in a mountain in the Itajubá city. The results pointed out to the efficiency of the tool but indicate some necessary care for their accurate use. Keywords: Topography, Elevation, Accuracy.  

Experimental and Numerical Assessment of Cross Flow Vertical Axis Wind Turbine

2019 ◽  
Author(s):  
Sivamani Seralathan ◽  
Micha Premkumar Thomai ◽  
Rian Leevinson Jayakumar ◽  
Basireddy Venkata Lokesh Reddy ◽  
Hariram Venkatesan
Keyword(s):  
Wind Turbine ◽  
Renewable Energy Sources ◽  
Cross Flow ◽  
Experimental Investigations ◽  
Speed Ratio ◽  
Positive Interaction ◽  
Polar Plot ◽  
Tip Speed Ratio ◽  
Wind Speeds ◽  
Low Wind Speeds

Abstract Due to increase in energy demand along with environmental awareness, the attention is shifting towards renewable energy sources. A wind turbine developed from Banki water turbine is used in this study as it starts at low-wind speeds and has high starting torque. Experimental investigations are carried out on a test rig equipped with open jet wind tunnel with wind velocity varying from 7 to 11 m/s. Later, 3D steady-state numerical analyses are performed using ANSYS CFX for better understanding of the flow physics of cross flow VAWT. The experimental investigations revealed that cross flow VAWT has a good self-starting ability at relatively low-wind speeds. A peak power coefficient (Cp, max) value of 0.059 is observed for the tip speed ratio (λ) of 0.30. As the tip speed ratio is raised further, the Cp value is observed to decrease gradually. The numerical simulations reveal the reason for the drop in Cp value. This is due to lessening of positive interaction between the flow and cross flow VAWT blades at higher λ due to vortex formation. The torque coefficient is found to decrease almost linearly from a peak value of around 0.49 at λ = 0 to a value of 0 around λ = 0.60. Polar plot between angle and torque shows that torque output of the turbine is nearly same in all directions which reinforce the potency of cross flow VAWT to be omni-directional as it produces the same performance regardless of wind directions.

Polar Plot

2016 ◽  
pp. 215-225
Author(s):  
Keon-Woong Moon
Keyword(s):  
Polar Plot

A three-dimensional turbulent boundary layer

1965 ◽  
Vol 22 (2) ◽  
pp. 285-304 ◽  
Author(s):  
A. E. Perry ◽  
P. N. Joubert
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Three Dimensional ◽  
Outer Part ◽  
Outer Region ◽  
Experimental Results ◽  
Mean Velocity ◽  
Polar Plot ◽  
Law Of The Wall ◽  
The Mean

The purpose of this paper is to provide some possible explantions for certain observed phenomena associated with the mean-velocity profile of a turbulent boundary layer which undergoes a rapid yawing. For the cases considered the yawing is caused by an obstruction attached to the wall upon which the boundary layer is developing. Only incompressible flow is considered.§1 of the paper is concerned with the outer region of the boundary layer and deals with a phenomenon observed by Johnston (1960) who described it with his triangular model for the polar plot of the velocity distribution. This was also observed by Hornung & Joubert (1963). It is shown here by a first-approximation analysis that such a behaviour is mainly a consequence of the geometry of the apparatus used. The analysis also indicates that, for these geometries, the outer part of the boundary-layer profile can be described by a single vector-similarity defect law rather than the vector ‘wall-wake’ model proposed by Coles (1956). The former model agrees well with the experimental results of Hornung & Joubert.In §2, the flow close to the wall is considered. Treating this region as an equilibrium layer and using similarity arguments, a three-dimensional version of the ‘law of the wall’ is derived. This relates the mean-velocity-vector distribution with the pressure-gradient vector and wall-shear-stress vector and explains how the profile skews near the wall. The theory is compared with Hornung & Joubert's experimental results. However at this stage the results are inconclusive because of the lack of a sufficient number of measured quantities.

Assessing accuracy of a non-invasive monitor for cardiac output, compared to the LiDCOrapid: the polar plot method

2013 ◽  
Vol 30 ◽  
pp. 48-48
Author(s):  
Lombana V. Anillo ◽  
R. Schiraldi ◽  
Martinez M.M. Lopez ◽  
G. Maggi ◽  
N. Brogly ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Polar Plot ◽  
Non Invasive
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