Study of Interference Effects on Chimneys Shruti, K; Rajesh, Sreeram; Sabareesh, GR ...
Journal of physics. Conference series,
08/2019, Letnik:
1276, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Fluid flow studies play a vital role in proper assessing of wind loadson buildings and other civil engineering structures with various shapes. The presence of adjacent structure may alter wind loads ...on the structure of interest, by altering the fluid dynamics surrounding the structure. This effect is termed as interference effect and it depends on various factors such as terrain category, wind angle, geometry & orientation of the structure, spacing between the structures etc. Thus, proper assessment of interference effect with above factors, can lead to efficient design of structures that can withstand the load variations due to the presence of interfering structures. The existing literature on wind interference effects, focuses more on experimental analysis of the problem, which is both expensive and time consuming. In this regard, computational fluid dynamics (CFD) approach can serve as a quicker and efficient tool. In an attempt to study the effect of geometry &orientation of structures on interference phenomenon, turbulent flows around the buildings, cooling towers and chimneys have been simulated through CFD approach by performing Large Eddy Simulation (LES). In the present study, interference factors of a typical chimney structure has been evaluated by considering the presence of an identical chimney at varying distances, under different wind angles.
A series of Ce
1 − x
–Zr
x
O
2 − δ
(x = 0.2, 0.5, and 0.8) mixed oxides were prepared by coprecipitation method and explored for selective oxidation of vanillyl alcohol employing O
2
and acetonitrile ...as the oxidant and solvent, respectively under base-free conditions. To ascertain the key factors responsible for vanillyl alcohol oxidation, the physicochemical properties of the synthesized catalysts were investigated by various characterization techniques namely, XRD, BET surface area, Raman, XPS, and H
2
-TPR. It was observed from this exercise that the catalytic activity dependents on the Ce:Zr mole ratio, which is related to the degree of reducibility of the catalyst. Interestingly, the catalytic activity is enhanced with the increase of Ce content in the Ce–Zr mixed oxide. Among the investigated catalysts, the Ce
0.8
Zr
0.2
O
2
combination exhibited a high catalytic activity with ~ 98% conversion and ~ 99% selectivity to vanillin. Smaller crystallite size, large BET surface area, more number of oxygen vacancies, improved redox properties, and strong synergetic interaction are found to be the key factors to promote the oxidation ability of Ce
0.8
Zr
0.2
O
2
catalysts towards vanillyl alcohol oxidation. Further, the influence of reaction parameters such as time, solvent, temperature, and oxygen pressure were also studied to optimize the catalytic process for vanillyl alcohol oxidation. As revealed by these studies, the high activity of Ce
0.8
Zr
0.2
O
2
catalyst could be retained up to five cycles without appreciable loss in the activity and selectivity.
Graphical Abstract
Nanosized Ce
0.8
Zr
0.2
O
2
catalyst exhibited an excellent catalytic activity and superior selectivity to vanillin in the liquid phase oxidation of vanillyl alcohol under ecofriendly conditions
Internet of Things (IoT) based healthcare monitoring system is becoming the present and the future of the medical field around the world. Here the monitoring system acquires the regular health ...details of hospital discharged patients like elderly patients, patients out of critical operations, and patients from remote areas, etc., and transmits it to the doctors. But the system is highly susceptible to sensor faults. Hence a data-driven hybrid approach of Hidden Markov Model (HMM) based on baum-welch algorithm with Support Vector Machine (SVM) is proposed to predict the abnormality caused by the medical sensors. The proposed work first perform the abnormality detection on the sensor data using the HMM based on baum-welch algorithm in which the normal data is separated from abnormal data followed by classifying the abnormal data as critical patient data or sensor fault data using the SVM. Here the proposed work efficiently performs fault diagnosis with an overall accuracy of 99.94% which is 0.59% better than the existing SVM model. And also a comparison is made between the hybrid approach and the existing ML algorithms in terms of recall and F1-score where the proposed approach outperforms the other algorithms with a recall value of 100% and F1-score of 99.7%.
Background and aims: Mutations in the cationic trypsinogen (protease, serine, 1 (trypsin 1); PRSS1) gene are causally associated with recurrent acute and chronic pancreatitis. We investigated whether ...mutations in the PRSS1 gene are associated with hereditary and non-hereditary pancreatitis. As a modifier role has been proposed for trypsin inhibitor (serine protease inhibitor, Kazal type I; SPINK1) mutations, the role of SPINK1 mutations in these patients was also analysed. Subjects and methods: The coding regions of PRSS1 and SPINK1 genes were sequenced in 290 controls and 198 patients, of whom 120 were diagnosed as idiopathic (ICP), 41 as alcoholic (ACP), and 37 as hereditary pancreatitis (HP). Twenty four unaffected relatives of HP probands were also analysed and genotype-phenotype correlations and statistical analyses were performed. Results: No mutations in the PRSS1 gene were detected in any of the patients, including HP patients, while the N34S mutation was observed in the SPINK1 gene in the majority of HP patients (73%). Similarly, 26.8% of ACP (11 of 41) and 32.5% (39 of 120) of ICP patients also had SPINK1 mutations. The N34S mutation was observed in both homozygous and heterozygous conditions. In comparison, only 2.76% of the control population had the N34S allele (p<0.001). The P55S mutation was observed in one ICP and one ACP patient, and in three normal individuals. Genotype-phenotype correlations did not suggest any significant difference in the age of onset, severity of disease, or pancreatic endocrine insufficiency in patients with or without mutated SPINK1 and irrespective of the allelic status of N34S SPINK1. Conclusions: Irrespective of the aetiology, mutations in the PRSS1 gene are not associated with chronic pancreatitis, including HP. In contrast, the N34S mutation in the SPINK1 gene shows a significant correlation in these patients. A comparable phenotype in terms of age of onset, diabetes mellitus, and other phenotypic features in patients with or without SPINK1 mutations and N34S homozygotes and heterozygotes suggests that there may still be involvement of other genetic or environmental factors.
Band gap characteristic of flexural metamaterial beams has been an active area of research for its potential application in providing low-frequency band gaps. The present work brings out ...investigations on flexural metamaterial beams, highlighting the influence of their design parameters. The metamaterial beams were fabricated by introducing periodic cavities in a thin uniform beam, and filling the cavities by a Viscoelastic Membrane (VEM), and a Resonant Mass (RM). Twelve different metamaterial beams were fabricated for experimental and numerical investigations, by varying the geometrical shape of the cavity or the type of VEM or the mass of RM. Vibration characteristics and band gaps of these metamaterial beams were studied through vibration trials on a vibration shaker. Their vibration characteristics were compared with that of a uniform beam, without any cavity. Two prominent low-frequency band gaps were discernible for the metamaterial beams, which are referred to as ‘local resonance band gaps (LRBGs)’. Dependence of these LRBGs on various design parameters of the metamaterial beam has been presented. Further, the band gap characteristic of a metamaterial beam has been compared to that of a beam with multiple-Tuned Mass Dampers to get further insight into the band gaps of a metamaterial structure.
Microvascular abnormalities and impaired gas transfer have been observed in patients with COVID-19. The progression of pulmonary changes in these patients remains unclear.
Do patients hospitalized ...with COVID-19 without evidence of architectural distortion on structural imaging exhibit longitudinal improvements in lung function measured by using 1H and 129Xe MRI between 6 and 52 weeks following hospitalization?
Patients who were hospitalized with COVID-19 pneumonia underwent a pulmonary 1H and 129Xe MRI protocol at 6, 12, 25, and 51 weeks following hospital admission in a prospective cohort study between November 2020 and February 2022. The imaging protocol was as follows: 1H ultra-short echo time, contrast-enhanced lung perfusion, 129Xe ventilation, 129Xe diffusion-weighted, and 129Xe spectroscopic imaging of gas exchange.
Nine patients were recruited (age 57 ± 14 median ± interquartile range years; six of nine patients were male). Patients underwent MRI at 6 (n = 9), 12 (n = 9), 25 (n = 6), and 51 (n = 8) weeks following hospital admission. Patients with signs of interstitial lung damage were excluded. At 6 weeks, patients exhibited impaired 129Xe gas transfer (RBC to membrane fraction), but lung microstructure was not increased (apparent diffusion coefficient and mean acinar airway dimensions). Minor ventilation abnormalities present in four patients were largely resolved in the 6- to 25-week period. At 12 weeks, all patients with lung perfusion data (n = 6) showed an increase in both pulmonary blood volume and flow compared with 6 weeks, although this was not statistically significant. At 12 weeks, significant improvements in 129Xe gas transfer were observed compared with 6-week examinations; however, 129Xe gas transfer remained abnormally low at weeks 12, 25, and 51.
129Xe gas transfer was impaired up to 1 year following hospitalization in patients who were hospitalized with COVID-19 pneumonia, without evidence of architectural distortion on structural imaging, whereas lung ventilation was normal at 52 weeks.
The Very Large Array Sky Survey (VLASS) is a synoptic, all-sky radio sky survey with a unique combination of high angular resolution ( 2 5), sensitivity (a 1 goal of 70 Jy/beam in the coadded data), ...full linear Stokes polarimetry, time domain coverage, and wide bandwidth (2-4 GHz). The first observations began in 2017 September, and observing for the survey will finish in 2024. VLASS will use approximately 5500 hr of time on the Karl G. Jansky Very Large Array (VLA) to cover the whole sky visible to the VLA (decl. > −40°), a total of 33 885 deg 2 . The data will be taken in three epochs to allow the discovery of variable and transient radio sources. The survey is designed to engage radio astronomy experts, multi-wavelength astronomers, and citizen scientists alike. By utilizing an "on the fly" interferometry mode, the observing overheads are much reduced compared to a conventional pointed survey. In this paper, we present the science case and observational strategy for the survey, and also results from early survey observations.
Abstract Alpinia galanga (L.) Willd. is a valuable medicinal crop found in specific tropical regions of southeast Asia. Its crude extracts are well known for their wide medicinal properties and many ...compounds identified from these extracts are of great interest currently. 1’S-1’-Acetoxychavicol acetate (ACA) obtained from rhizomes of A.galanga is one such well-illustrated compound. This study strives to progress and simplifies the purification protocol for ACA from A.galanga rhizomes. It also studies the cytotoxicity and antiproliferative activity of ACA against Dukes’ type B, colorectal adenocarcinoma (SW480). HPLC standardisation was carried out for purification of ACA from rhizomes of Alpinia galanga . MTT assay was executed to estimate the IC50 value of ACA against SW480 cell line. This value was used to study the apoptosis, nuclear morphological changes and mitochondrial membrane permeability using Acridine orange/ethidium bromide, DAPI, and JC-1 staining. The DNA fragmentation assay was used to substantiate the nuclear fragmentation of DNA observed in the DAPI staining. Further, cell cycle analysis was performed using flow cytometry to study the exact stage of the cell cycle where SW480 cells are arrested due to ACA, western blot analysis of relevant genes were done to further understand at molecular level. A comprehensive 1.89 g of 1’S-1’-Acetoxychavicol acetate (ACA) was recovered from 500 g of A.galanga rhizomes. ACA significantly suppressed the proliferation of SW480 cells at an IC50 of 80 μM (48 h). The mode of SW480 cell death due to ACA was initially identified as apoptosis and cell cycle halted at G0 /G1 checkpoint with considerable DNA damage and mitochondrial depolarization. The expression of p21 was increased and concomitantly Cyclin D was downregulated in ACA treated in comparison to control. This study suggests that 1’S-1’-Acetoxychavicol acetate has potent anti-colorectal adenocarcinoma activity.
Selective allylic oxidation of cyclohexene was investigated over nanostructured CeO
2
/SiO
2
and CeO
2
–Sm
2
O
3
/SiO
2
catalysts synthesized by a feasible deposition precipitation method. The CeO
2
...–Sm
2
O
3
/SiO
2
catalyst showed excellent catalytic efficiency with ~89 % cyclohexene conversion and ~90 % selectivity for allylic products (i.e., 2-cyclohexen-1-ol and 2-cyclohexene-1-one), while only ~50 and ~35 % cyclohexene conversion was observed, respectively, over CeO
2
/SiO
2
and CeO
2
catalysts. Systematic characterization of the designed catalysts was undertaken to correlate their catalytic activity with the physicochemical properties using X-ray diffraction (XRD) analysis, Brunauer–Emmett–Teller (BET) surface area measurements, Raman spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and NH
3
-temperature programmed desorption (TPD) techniques. The results revealed that doping of Sm
3+
into the ceria lattice and simultaneous dispersion of resultant Ce–Sm mixed oxides on the silica surface led to improved structural, acidic, and catalytic properties. The better catalytic efficiency of CeO
2
–Sm
2
O
3
/SiO
2
was due to high specific surface area, more structural defects, and high concentration of strong acid sites, stimulated by synergistic interaction between various oxides in the catalyst. The cyclohexene conversion and selectivity for allylic products depended on the reaction temperature, nature of solvent, molar ratio of cyclohexene to oxidant, and reaction time. Possible reaction pathways are proposed for selective allylic oxidation of cyclohexene towards 2-cyclohexen-1-ol and 2-cyclohexene-1-one products.
Graphical Abstract
SiO
2
-supported CeO
2
–Sm
2
O
3
nanocatalyst exhibited outstanding catalytic performance with superior selectivity for allylic products in liquid-phase selective oxidation of cyclohexene under mild reaction conditions.
The transport of pregnant women to an appropriate health facility plays a pivotal role in preventing maternal deaths. In India, state-run call-centre based ambulance systems ('108' and '102'), along ...with district-level Janani Express and local community-based innovations, provide transport services for pregnant women. We studied the role of '108' ambulance services in transporting pregnant women routinely and obstetric emergencies in India.
This study was an analysis of '108' ambulance call-centre data from six states for the year 2013-14. We estimated the number of expected pregnancies and obstetric complications for each state and calculated the proportions of these transported using '108'. The characteristics of the pregnant women transported, their obstetric complications, and the distance and travel-time for journeys made, are described for each state.
The estimated proportion of pregnant women transported by '108' ambulance services ranged from 9.0 % in Chhattisgarh to 20.5 % in Himachal Pradesh. The '108' service transported an estimated 12.7 % of obstetric emergencies in Himachal Pradesh, 7.2 % in Gujarat and less than 3.5 % in other states. Women who used the service were more likely to be from rural backgrounds and from lower socio-economic strata of the population. Across states, the ambulance journeys traversed less than 10-11 km to reach 50 % of obstetric emergencies and less than 10-21 km to reach hospitals from the pick-up site. The overall time from the call to reaching the hospital was less than 2 h for 89 % to 98 % of obstetric emergencies in 5 states, although this percentage was 61 % in Himachal Pradesh. Inter-facility transfers ranged between 2.4 % -11.3 % of all '108' transports.
A small proportion of pregnant women and obstetric emergencies made use of '108' services. Community-based studies are required to study knowledge and preferences, and to assess the potential for increasing or rationalising the use of '108' services.
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