projected area
Recently Published Documents


TOTAL DOCUMENTS

204
(FIVE YEARS 49)

H-INDEX

23
(FIVE YEARS 2)

2022 ◽  
Vol 8 ◽  
Author(s):  
Kiernan Kelty ◽  
Tori Tomiczek ◽  
Daniel Thomas Cox ◽  
Pedro Lomonaco ◽  
William Mitchell

This study investigates the potential of a Rhizophora mangrove forest of moderate cross-shore thickness to attenuate wave heights using an idealized prototype-scale physical model constructed in a 104 m long wave flume. An 18 m long cross-shore transect of an idealized red mangrove forest based on the trunk-prop root system was constructed in the flume. Two cases with forest densities of 0.75 and 0.375 stems/m2 and a third baseline case with no mangroves were considered. LiDAR was used to quantify the projected area per unit height and to estimate the effective diameter of the system. The methodology was accurate to within 2% of the known stem diameters and 10% of the known prop root diameters. Random and regular wave conditions seaward, throughout, and inland of the forest were measured to determine wave height decay rates and drag coefficients for relative water depths ranging 0.36 to 1.44. Wave height decay rates ranged 0.008–0.021 m–1 for the high-density cases and 0.004–0.010 m–1 for the low-density cases and were found to be a function of water depth. Doubling the forest density increased the decay rate by a factor two, consistent with previous studies for other types of emergent vegetation. Drag coefficients ranged 0.4–3.8, and were found to be dependent on the Reynolds number. Uncertainty in the estimates of the drag coefficient due to the measured projected area and measured wave attenuation was quantified and found to have average combined standard deviations of 0.58 and 0.56 for random and regular waves, respectively. Two previous reduced-scale studies of wave attenuation by mangroves compared well with the present study when their Reynolds numbers were re-scaled by λ3/2 where λ is the prototype-to-model geometric scale ratio. Using the combined data sets, an equation is proposed to estimate the drag coefficient for a Rhizophora mangrove forest: CD = 0.6 + 3e04/ReDBH with an uncertainty of 0.69 over the range 5e03 < ReDBH < 1.9e05, where ReDBH is based on the tree diameter at breast height. These results may improve engineering guidance for the use of mangroves and other emergent vegetation in coastal wave attenuation.


Urban Climate ◽  
2022 ◽  
Vol 41 ◽  
pp. 101033
Author(s):  
Zhengrong Li ◽  
Xiwen Feng ◽  
Xueke Fan ◽  
Jingting Sun ◽  
Zhaosong Fang

2021 ◽  
Author(s):  
Biying Han ◽  
Qi Wu ◽  
Chen Yu ◽  
Haiming Wang ◽  
Xiqi Gao ◽  
...  

Very high wind loads represent one of the major problems for the ultralarge-scale 5G base station array at the sub-6 GHz band, where dozens of or hundreds of antennas are used. An ultracompact dual-polarized cross-dipole antenna with an extremely small overall projected area is presented. The array with low wind load is realized by miniaturized cross dipoles and the replacement of the traditional ground plane with a defected ground structure (DGS) and metal mesh reflector. The DGS is utilized to realize size reduction and isolation enhancement. The projected area of the antenna is reduced by 70%. Therefore, each antenna in the array can be independently packaged using a streamlined radome with a low wind load. And the inter-radome spacing is large enough to make holes that are used to further reduce wind load. The antenna prototype is designed, fabricated, and measured for the sub-1 GHz band. The measured results show that the impedance bandwidth is 680-970 MHz, the polarization isolation is higher than 20 dB, and the gain is around 6.5 dBi. It is verified that the proposed ultracompact antenna of high radiation performance is very suitable for an ultralarge-scale array of low wind load in a 5G base station.


2021 ◽  
Author(s):  
Biying Han ◽  
Qi Wu ◽  
Chen Yu ◽  
Haiming Wang ◽  
Xiqi Gao ◽  
...  

Very high wind loads represent one of the major problems for the ultralarge-scale 5G base station array at the sub-6 GHz band, where dozens of or hundreds of antennas are used. An ultracompact dual-polarized cross-dipole antenna with an extremely small overall projected area is presented. The array with low wind load is realized by miniaturized cross dipoles and the replacement of the traditional ground plane with a defected ground structure (DGS) and metal mesh reflector. The DGS is utilized to realize size reduction and isolation enhancement. The projected area of the antenna is reduced by 70%. Therefore, each antenna in the array can be independently packaged using a streamlined radome with a low wind load. And the inter-radome spacing is large enough to make holes that are used to further reduce wind load. The antenna prototype is designed, fabricated, and measured for the sub-1 GHz band. The measured results show that the impedance bandwidth is 680-970 MHz, the polarization isolation is higher than 20 dB, and the gain is around 6.5 dBi. It is verified that the proposed ultracompact antenna of high radiation performance is very suitable for an ultralarge-scale array of low wind load in a 5G base station.


2021 ◽  
pp. 2102276
Author(s):  
Alessandro Gandin ◽  
Veronica Torresan ◽  
Lorenzo Ulliana ◽  
Tito Panciera ◽  
Paolo Contessotto ◽  
...  
Keyword(s):  

2021 ◽  
Author(s):  
Lujing Qian ◽  
Yubang Yang ◽  
Shuyu Sun ◽  
Tengchao Huang

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Bünyamin Demir ◽  
Bahadır Sayıncı ◽  
Mehmet Yaman ◽  
Ahmet Sümbül ◽  
Ercan Yıldız ◽  
...  

Abstract In the present study, the biochemical composition and shape and dimensional traits of 25 rosehip (Rosa canina) genotypes were investigated. The shape and dimensional traits were determined by image processing technique. Seed-propagated rosehip genotypes belonging to R. canina were collected from the natural flora of Mesudiye (Ordu) and Talas (Kayseri) districts. Antioxidant activity (39.510–72.673 mmol · kg−1), total flavonoids (287.80–1,686.20 mg quercetin equivalent (QE) · kg−1) and total phenolics (38,519.40–79,080.60 mg gallic acid equivalent · kg−1) of the genotypes exhibited large variations. Width (12.2 mm) and thickness (12.5 mm) of fruits averages were found to be close to each other. The genotypes exhibited fruit lengths between 12.0 mm and 29.5 mm. Average projected area at horizontal orientation (179.7 mm2) was greater than the projected area at vertical orientation (120.4 mm2). Sphericity average was calculated as 71.4%. According to principal component (PC) analysis, the most important dimensional traits discriminating genotypes from each other were identified as surface area, geometric mean diameter and volume. In terms of shape attributes, distinctive differences were observed in sphericity, circularity, elongation and surface closure rates (SCR) of the genotypes. According to elliptic Fourier analysis (EFA), genotypes look like a sphere. In terms of shape, there were long, spherical, flat bottomed, pointed bottomed and asymmetric-looking genotypes indicating how environment and genotype affect the fruit shape. The greatest shape variation was transverse contraction and expansion. According to the clustering analysis for shape attributes, rosehip genotypes were classified into six groups. Dendrogram, scatter plots of linear discriminant analysis and paired comparison test results put forth the shape differences of the genotype successfully.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1309
Author(s):  
Lucila Garcia-Contreras ◽  
Vasu Sethuraman ◽  
Masha Kazantseva ◽  
Anthony Hickey

Liposomes, as vehicles alone or in combination with rifampicin (RIF) microparticles (RMs), were evaluated as vehicles to enhance the permeation of RIF into granulomas. RIF liposomes (RLs) were extruded through a 0.1 µm polypropylene membrane. RMs were prepared by the solvent evaporation method. Four weeks after infection, guinea pigs (GPs) were assigned to groups treated with a combination of RM-RLs or RLs alone. RLs were nebulized after extrusion whereas RMs were suspended in saline and nebulized to GPs in a nose-only inhalation chamber. Necropsy was performed after the treatment; the lungs and spleen were resected for bacteriology. RLs had mean diameters of 137.1 ± 33.7 nm whereas RMs had a projected area diameter of 2.48 µm. The volume diameter of RMs was 64 ± 1 µm, indicating that RMs were aggregated. The treatment of TB-infected GPs with RLs significantly reduced their lung bacterial burden and wet spleen weight compared with those treated with blank liposomes. The treatment of TB-infected animals with RM-RLs also reduced their lung bacterial burden and wet spleen weight even though these reductions were not statistically different. Based on these results, the permeation of RIF into granulomas appears to be enhanced when encapsulated into liposomes delivered by the pulmonary route.


2021 ◽  
Vol 43 (7) ◽  
pp. 547-556
Author(s):  
Hyun-Hoon Jung ◽  
Ji-Yun Seon ◽  
Tea-Hyoung Lim ◽  
Seung-Mok Lee ◽  
Seung-Kyun Park

Objectives : MBR (Membrane BioReactor) is well established wastewater treatment that combines biological and physical method with high quality effluent. The purpose of this study is to utilize an air scouring integral immersed hollow fiber membrane module through efficient structural improvement developed to reduce membrane fouling. In addition, the scouring aeration was optimized to determine the energy savings.Methods : In this study, membrane fouling test was evaluated in various of scouring aeration flow with range of 40 to 140 m3 air/m2 projected area・hr and influent and effluent was analyzed by water quality standard.Results and Discussion : In scouring aeration test, effective membrane contamination control was possible with supplying 80 m3 air/m2 projected area・hr, scouring aeration rate gradually increased the differential pressure from below 60 m3 air/m2 projected area・hr, which accelerates the membrane contamination phenomenon. By reducing more than 20% of the existing general scouring aeration rate of 100~140 m3 air/m2 projected area・hr, electricity and maintenance costs can be reduced due to aeration control, and at the same time, it is confirmed that the technology has the same performance. The pilot test results of SJMBR with the developed module showed that the effluent was BOD of 1.4 mg/L, COD of 4.2 mg/L, SS of 0.7 mg/L, T-N of 5.56 mg/L, T-P of 0.56 mg/L, total coliform group of 0 ea/mL, and ecotoxicity of 0 TU, respectively.Conclusions : These results are combined, when using an air scouring integral immersed hollow fiber membrane module, it is expected to reduce the amount of scouring air by more than 20% by optimizing the supply of scouring air. In addition, it can also be determined by technology that satisfy the same permeability and treated water quality as existing technologies.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 835
Author(s):  
Sara B. E. Andersson ◽  
Göran Frenning ◽  
Göran Alderborn

The objective of this study was to determine the intrinsic drug dissolution rate (IDR) and the solute effective transport rate of some drugs, using a single particle dissolution technique, satisfying qualified dissolution conditions. The IDR of three poorly water-soluble compounds was measured in milli-Q water using four different fluid velocities. The enveloped surface area of the particles was calculated from the projected area and the perimeter of the particle observed in the microscope. Furthermore, computational fluid dynamics (CFD) simulations were used to theoretically investigate the flow conditions and dissolution rate, comparing box shaped particles and spherical particles with similar dimensions and surface area as the particles used the experiments. In this study, the IDR measurement of the single particles was determined within 5–60 min using particles with an initial projected area diameter (Dp) between 37.5–104.6 µm. The micropipette-assisted microscopy technique showed a good reproducibility between individual measurements, and the CFD simulations indicated a laminar flow around the particles at all flow velocities, even though there were evident differences in local particle dissolution rates. In conclusion, the IDR and solute effective transport rate were determined under well-defined fluid flow conditions. This type of approach can be used as a complementary approach to traditional dissolution studies to gain in-depth insights into the dissolution process of drug particles.


Sign in / Sign up

Export Citation Format

Share Document