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Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 168
Author(s):  
Adam Rus Nugroho ◽  
Ichiro Tamagawa ◽  
Morihiro Harada

While many studies on the relationship between climate modes and rainfall in Indonesia already exist, studies targeting climate modes’ relationship to streamflow remain rare. This study applied multiple regression (MR) models with polynomial functions to show the teleconnection from the two prominent climate modes—El Niño–Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD)—to streamflow regimes in eight rivers in Java, Indonesia. Our MR models using data from 1970 to 2018 successfully show that the September–November (SON) season provides the best predictability of the streamflow regimes. It is also found that the predictability in 1970–1989 was better than that in 1999–2018. This suggests that the relationships between the climate modes and streamflow in Java were changed over periods, which is suspected due to the river basin development. Hence, we found no clear spatial distribution patterns of the predictability, suggesting that the effect of ENSO and IOD are similar for the eight rivers. Additionally, the predictability of the high flow index has been found higher than the low flow index. Having elucidated the flow regimes’ predictability by spatiotemporal analysis, this study gives new insight into the teleconnection of ENSO and IOD to the Indonesian streamflow.


2021 ◽  
pp. 163-172
Author(s):  
Junxiang Gao ◽  
Xiaoliang Gao ◽  
Wei Zou

Taking the lubrication system of rotary tillage engine as the research object, this paper makes a three-dimensional simulation study on the oil flow characteristics in the lubricating oil passage. The oil supply of the oil pump shall be greater than the circulating oil required by the lubrication system to ensure the lubrication of the rotary cultivator. Lubrication system is an important part to ensure the reliability and durability of rotary cultivator. The key component to achieve its performance is the oil pump. The geometric model of lubricating oil flow field in rotary tiller lubrication system is established by using FLUENT software. The results show that the pressure drop in the lubricating oil passage of the main bearing is the largest under the same working conditions. In the oil passage of the cylinder head, the pressure drop of the front main oil passage is the largest and the oil discharge is the largest. Add 1.6mm oil pump rotor on the basis of the thickness of the original oil pump rotor, the oil flow at the connecting rod nozzle reaches the flow index of the original rotary cultivator, and there is no cylinder pulling phenomenon of the rotary cultivator.


Author(s):  
Guoming Chen ◽  
Haihong Ma ◽  
Zhengfa Zhou ◽  
Fengmei Ren ◽  
Weibing Xu

Abstract The purpose of this study is to improve the properties of the feedstocks and shape retention of debinded parts by the reaction between 17-4PH stainless steel powders. Carboxyl-terminated hyperbranched polyester (CTHP) and epoxy-terminated hyperbranched polyester (ETHP) were used to treat the powders, and termed as CTHP-m and ETHP-m with carboxyl and epoxy group, respectively. Comparing with pristine, CTHP-m and ETHP-m, feedstock prepared from equal amount of CTHP-m and ETHP-m (CTHP-m/ETHP-m) possessed more excellent properties. The experimental results showed that the critical solids loading, flexural modulus, density and melt flow index of CTHP-m/ETHP-m feedstock were 63.8 vol.%, 2800 Mpa, 5.06 g/cm3 and 62 g/10min, respectively, which were obviously higher than that of others. Also, the shape retention of CTHP-m/ETHP-m debinded parts was the best of all the samples. The improved properties of CTHP-m/ETHP-m feedstock were attributed to the powder interaction between CTHP-m and ETHP-m formed by the chemical reaction between epoxy and carboxyl group.


Author(s):  
Dipanjana Ash ◽  
Sutapa Biswas Majee ◽  
Gopa Roy Biswas

Organogelators induce 3-D networked structures in apolar solvent molecules via cross-linking of non-covalent self-assembled aggregates below the gelation temperature. The objective of the present investigation was to evaluate the effects of different Span 40 concentrations on gelation kinetics and drug release behaviour of topical soybean oleogels. An inversely proportional relationship was observed between gelation time, melt flow index and concentration of Span 40 in soybean oleogels. Gompertz model was employed on gelation kinetics data to determine organogelator and oil parameters which are assumed to be associated with thermal stability and gel flexibility respectively. Formulation OGS2 (18% W/V Span 40) formed less viscous, thermally stable and presumably more flexible oleogel compared to other formulations. Nearly ideal zero-order release of paracetamol was achieved from OGS*2 following Fickian diffusion. However, slow drug release profiles, higher t50 values were observed with oleogels having 20-24% w/v Span 40 which followed Korsmeyer-Peppas kinetics with non-Fickian diffusion.


Foods ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3130
Author(s):  
Vojtěch Kumbár ◽  
Sylvie Ondrušíková ◽  
Daniel Trost ◽  
Adam Polcar ◽  
Šárka Nedomová

Liquid egg products are one of the basic raw materials for the food industry. Knowledge of their rheological and flow behaviour in real technical elements is absolutely necessary for the selection of suitable technological equipment for their processing. In this article, the rheological properties of liquid egg products were determined. Eggs from six different species of poultry are used: domestic hen (Gallus gallus domesticus) hybrid Hisex Brown; Japanese quail (Coturnix japonica); German carrier goose (Anser anser f. domestica); domestic ducks (Anas platyrhynchos f. domestica); domestic guinea fowl (Numida meleagris f. domestica); and domestic turkeys (Meleagris gallopavo f. domestica). Liquid egg products showed pseudoplastic behaviour in range of shear strain rates from 0.2 up to 200 s−1 and at the temperature of 18 °C. Thus, the flow curves were constructed using the Ostwald-de Waele rheological model, with respect to the pseudoplastic behaviour of liquid egg products. According to the values of the coefficients of determination (R2), the sum of squared estimate of errors (SSE) and the root mean square error (RMSE), this model was appropriately chosen. Using the consistency coefficient K, the flow index n and the adjusted equations for the flow rate of technical and biological fluids in standard pipelines, the 3D velocity profiles of liquid egg products were successfully modelled. The values of the Reynolds number of the individual liquid egg products were calculated, and the type of flow was also determined. A turbulent flow has been detected for some liquid egg products.


2021 ◽  
Vol 23 (12) ◽  
pp. 146-157
Author(s):  
Afroza Bano ◽  
◽  
Manish Kumar Gupta ◽  

Friction-based welding is one of the most cost-effective and dependable methods for joining thermoplastics. However, there has been minimal work that has demonstrated the procedure/methods/equipment for welding two distinct types of thermoplastics. There is, nevertheless, a significant possibility of connecting the various thermoplastic materials by matching their melt flow index (MFI). One way for modifying the MFI is to reinforce it with micro/nano sized fillers. Fused deposition modelling (FDM) is a fast prototyping technology that employs thermoplastic-based filament to print components. The current study focuses on connecting aluminium (Al) metal powder reinforced acrylonitrile butadiene styrene (ABS) and polyamide 6 (PA6) thermoplastic substrates (3D printed by FDM) utilising friction welding (FW) / friction stir welding (FSW) / friction stir spot welding (FSSW). It was observed that the PA6 with 50% Al fillers (PA6-50% Al) and ABS matrix with 15% Al fillers (ABS-15% Al) produced MFIs of 11.97g/10min and 11.57g/10min, respectively.


Author(s):  
Rupinder Singh ◽  
Sanjeev Kumar ◽  
Amrinder Pal Singh ◽  
Yang Wei

In the past two decades number of studies have been reported on the use of thermoplastics as a substrate for 3D printed patch antennas. However, no work has been reported on the thermoplastic-thermosetting composite-based substrate for 3D printed patch antennas and their mechanical, morphological, rheological, and radiofrequency (RF) characterization for sensing applications. In this study low-density polyethylene (LDPE) and LDPE-5% bakelite (BAK) composite-based patch antenna (resonating frequency 2.45 GHz) were printed (for secondary recycling) on fused deposition modeling (FDM) setup. The RF characteristics were measured using a vector network analyzer (VNA). Ring resonator test was used for measuring the dielectric properties of substrates (which suggests that the dielectric constant ([Formula: see text]) and loss tangent ([Formula: see text]) for LDPE was 2.282 and 0.0045, whereas for LDPE-5%BAK the calculated [Formula: see text] and [Formula: see text] was 2.0663, 0.0051 respectively). This study highlights that for the LDPE-5%BAK composite there was a marginal increase in the size of the patch antenna; but this resulted in improved transmittance, gain, and return loss for typical sensor applications. As regards to printability of substrate, 5% BAK resulted in a melt flow index (MFI) of 9.96 g/10 min in contrast to 12.208 g/10 min for a neat LDPE sample. The selected LDPE-5%BAK composite resulted in peak strength (PS) and break strength (BS) of 16.08 MPa and 14.47 MPa (at 180 °C screw temperature, 110 rpm, and 11 kg load) while processing with a twin-screw extruder (TSE), which was observed better than the neat LDPE (PS 11.98 MPa, BS 10.79 MPa). The results were supported with porosity (%), surface roughness (Ra) analysis based upon scanning electron microscopy (SEM) and bond strength using attenuated total reflection (ATR) based Fourier transformed infrared (FTIR) analysis.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Cristina Pascual-González ◽  
Cillian Thompson ◽  
Jimena de la Vega ◽  
Nicolás Biurrun Churruca ◽  
Juan P. Fernández-Blázquez ◽  
...  

Purpose This paper aims to develop a novel strategy to manufacture poly-lactic acid (PLA) filaments reinforced with Mg particles for fused filament fabrication of porous scaffolds for biomedical applications. Design/methodology/approach The mixture of PLA pellets and Mg particles was extruded twice, the second time using a precision extruder that produces a filament with zero porosity, constant diameter and homogeneous dispersion of Mg particles. The physico-chemical properties of the extruded filaments were carefully analysed to determine the influence of Mg particles on the depolymerisation of PLA during high temperature extrusion and the optimum melt flow index to ensure printability. Findings It was found that the addition of a polyethylene glycol (PEG) plasticizer was necessary to allow printing when the weight fraction of Mg was above 4%. It was possible to print porous face-centre cubic scaffolds with good geometrical accuracy and minimum porosity with composite filaments containing PEG. Originality/value The new strategy is easily scalable and seems to be very promising to manufacture biodegradable thermoplastic/metal composite filaments for 3D printing that can take advantage of the different properties of both components from the viewpoint of tissue engineering.


2021 ◽  
Vol 22 (4) ◽  
pp. 40-49
Author(s):  
A.N. Martekha ◽  
◽  
V.N. Andreev ◽  

Rheological properties are an important parameter for the quality of mayonnaise. This article in-vestigated the effect of adding olive oil on the rheological properties and color change of mayon-naise. The influence of the storage time of mayonnaise in the refrigerator on the change in rheo-logical properties was also investigated. Mayonnaise was prepared on a laboratory rotary disperser of the Turrex type with a rotor / stator system with a rotor speed range (10000-30000 rpm) at room temperature. Mayonnaise contains 75% oil with varying proportions of sunflower oil and ol-ive oil. Rheological measurements were carried out on a Brookfield rotary viscometer with con-centric cylinders at temperatures of 10 ° C and 25 ° C. Based on the data obtained, the consistency coefficient of the rheological parameters, the flow index and the apparent viscosity were calculat-ed. The color of the test samples of mayonnaise was measured using a three-color colorimeter. All mayonnaise samples exhibit non-Newtonian pseudoplastic flow with a defined thixotropic loop area. Research results have shown that the addition of olive oil affects the rheological properties and color of mayonnaise. The addition of olive oil to the oil phase of mayonnaise reduces shear stress, apparent viscosity, consistency factor and color change at 25 ° C and 10 ° C. When storing mayonnaise in the refrigerator for 15 days, the rheological parameters change. Sunflower oil may-onnaise (75%) has the highest value (L), which means it is measured instrumentally as the bright-est.


2021 ◽  
Author(s):  
Achia Nemet ◽  
Michael Mimouni ◽  
Fadi Haddad ◽  
Shadi Safuri ◽  
Asaf Achiron ◽  
...  

Abstract PURPOSE: Pseudophakic cystoid macular edema (CME) occurs in up to 2% of uneventful cataract surgeries. This study evaluates changes in macular blood flow succeeding uneventful phacoemulsification cataract extraction among otherwise visually healthy subjects.METHODS: This prospective study included 18 eyes of 18 patients undergoing routine phacoemulsification. Optical coherence tomography angiography (OCT-A) was performed using the Angio-Retina 6x6mm protocol with the XR Avanti Angio-Vue system (Optovue Inc., Fremont, California) prior to the surgery and 4-8 weeks thereafter. Exclusion criteria included motion artifacts, segmentation errors and signal strength index (SSI) ˂40. The main outcome measure was change in flow index (FI) measured in all 4 retinal segmentation layers within an area of 1mm diameter around the foveal center.RESULTS: Following surgery, a significant increase in SSI (46.65±8.62 versus 53.12±8.07, p=0.01), superficial plexus FI (0.98±0.23 versus 1.16±0.16, p=0.02) and deep plexus FI (0.54±0.46 versus 0.93±0.39, p=0.01) was found. No significant changes were noted in the outer retina or the choriocapillaris. CONCLUSION: The study demonstrates a significant increase in FI in the superficial and deep retinal plexus following uneventful cataract surgery, with the greatest changes occurring in the latter. These findings corroborate evidence from structural imaging and support the vascular etiology of pseudophakic CME.


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