scholarly journals Drainage of a Water Tank with Pipe Outlet Loaded by a Passive Rotor

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1872
Author(s):  
Mohamed Elgamal ◽  
Karim Kriaa ◽  
Mohamed Farouk
Keyword(s):  
Negative Impact ◽  
Angular Speed ◽  
Temporal Variations ◽  
Speed Ratio ◽  
Water Tank ◽  
Drainage Rate ◽  
Processing Techniques ◽  
First Time ◽  
Engineering Projects ◽  
Pipe Outlet

The optimal design of pipe outlets is an essential objective for many engineering projects. For the first time, this paper reports the results of a laboratory investigation on the effect of using a passive rotor (added at the pipe outlet) on the outlet performance. Different sizes and numbers of blades of rotors were considered. Through the Tracker software package, video and image processing techniques were applied to capture the temporal variations of the tank water depth and the passive rotor’s angular speed. In addition, a normalized average drainage rate (NADR) parameter is defined to quantify the changes in the tank drainage rate as a result of passive rotor utilization. It is noted that adding a 4-bladed symmetric passive rotor will increase NADR by up to 9.0%. The study also shows that the highest increase in NADR is attained when the rotor diameter size is approximately 1.73 times the pipe outlet’s diameter for the case of symmetric 4-blade rotors, and the corresponding average tip rotor speed ratio is 1.65. It is also found that using an asymmetric 3-blade rotor has a negative impact on the NADR due to the significant perturbation produced by the rotor asymmetry.

A novel predictive method for filler coflocculation with cellulose microfibrils

TAPPI Journal ◽  
2019 ◽  
Vol 18 (11) ◽  
pp. 653-664
Author(s):  
IGNACIO DE SAN PIO ◽  
KLAS G. JOHANSSON ◽  
PAUL KROCHAK
Keyword(s):  
Negative Impact ◽  
High Strength ◽  
Strength Properties ◽  
Cellulose Microfibrils ◽  
Paper Strength ◽  
Flow Loop ◽  
Cationic Starch ◽  
Reflectance Measurement ◽  
Drainage Rate ◽  
Complete Study

Different strategies aimed at reducing the negative impact of fillers on paper strength have been the objective of many studies during the past few decades. Some new strategies have even been patented or commercialized, yet a complete study on the behavior of the filler flocs and their effect on retention, drainage, and formation has not been found in literature. This type of research on fillers is often limited by difficulties in simulating high levels of shear at laboratory scale similar to those at mill scale. To address this challenge, a combination of techniques was used to compare preflocculation (i.e., filler is flocculated before addition to the pulp) with coflocculation strategies (i.e., filler is mixed with a binder and flocculated before addition to the pulp). The effect on filler and fiber flocs size was studied in a pilot flow loop using focal beam reflectance measurement (FBRM) and image analysis. Flocs obtained with cationic polyacrylamide (CPAM) and bentonite were shown to have similar shear resistance with both strategies, whereas cationic starch (CS) was clearly more advantageous when coflocculation strategy was used. The effect of flocculation strategy on drainage rate, STFI formation, ash retention, and standard strength properties was measured. Coflocculation of filler with CPAM plus bentonite or CS showed promising results and produced sheets with high strength but had a negative impact on wire dewatering, opening a door for further optimization.

scholarly journals Hydrostatic Densitometer for Monitoring Density in Freshwater to Hypersaline Water Bodies

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1842
Author(s):  
Ziv Mor ◽  
Hallel Lutzky ◽  
Eyal Shalev ◽  
Nadav G. Lensky
Keyword(s):  
Continuous Monitoring ◽  
Pressure Sensors ◽  
Temporal Variations ◽  
Dead Sea ◽  
Conductivity Measurements ◽  
Lake Levels ◽  
Density Profiles ◽  
Water Column Stratification ◽  
Hypersaline Water ◽  
First Time

Density, temperature, salinity, and hydraulic head are physical scalars governing the dynamics of aquatic systems. In coastal aquifers, lakes, and oceans, salinity is measured with conductivity sensors, temperature is measured with thermistors, and density is calculated. However, in hypersaline brines, the salinity (and density) cannot be determined by conductivity measurements due to its high ionic strength. Here, we resolve density measurements using a hydrostatic densitometer as a function of an array of pressure sensors and hydrostatic relations. This system was tested in the laboratory and was applied in the Dead Sea and adjacent aquifer. In the field, we measured temporal variations of vertical profiles of density and temperature in two cases, where water density varied vertically from 1.0 × 103 kg·m−3 to 1.24 × 103 kg·m−3: (i) a borehole in the coastal aquifer, and (ii) an offshore buoy in a region with a diluted plume. The density profile in the borehole evolved with time, responding to the lowering of groundwater and lake levels; that in the lake demonstrated the dynamics of water-column stratification under the influence of freshwater discharge and atmospheric forcing. This method allowed, for the first time, continuous monitoring of density profiles in hypersaline bodies, and it captured the dynamics of density and temperature stratification.

scholarly journals Impact of VOCs on the formation of ozone in a central China city during severe pollution periods

2018 ◽  
Author(s):  
Bowei Li ◽  
Steven Sai Hang Ho ◽  
Sunling Gong ◽  
Jingwei Ni ◽  
Huairui Li ◽  
...  
Keyword(s):  
Temporal Variations ◽  
Central China ◽  
Compressed Natural Gas ◽  
Pmf Model ◽  
Sampling Campaign ◽  
Time Period ◽  
Ozone Formation Potential ◽  
Range Transport ◽  
Volatile Organic ◽  
First Time

Abstract. In this work, a five-month sampling campaign was conducted for volatile organic compounds (VOCs) for the first time in Zhengzhou City, Henan province, China, where ozone (O3) pollution has shown an increasing trend in recent years. Fifty-seven VOCs defined by the Photochemical Assessment Monitoring Stations (PAMS) were sampled using canister method. Meanwhile, other O3 precursor gases were monitored online at four different sites between the time period of May–September, 2017. The results indicated that the average mixing ratio of ΣPAMS (31.57 ± 23.35 ppbv) in Zhengzhou was lower than the other megacities in China, while alkyne was in a significantly higher proportion. The abundances, compositions and ratios of PAMS showed strong spatial and temporal variations. Alkenes were the largest contributors to the ozone formation potential (OFP). On clear days, higher O3 levels were often accompanied with high ΣPAMS/NOx ratio at each site, demonstrating that the VOCs were more sensitive during the O3 formation period in Zhengzhou. Furthermore, source apportionmemt was conducted with Positive Matrix Factorization (PMF) model, and it was found that the use of compressed natural gas (CNG), the evaporation of gasoline and the exhaust from vehicles were the important sources for ambient VOCs at all four sites. Besides, the meterological conditions and long-range transport from other surrounding provinces also had an impact on the air quality determined using the cluster analysis. It is worth mentioning that the reduction in VOCs' emissions is necessary to suppress the O3 pollution.

scholarly journals Spatial and temporal variations of CO<sub>2</sub> mole fractions observed at Beijing, Xianghe and Xinglong in North China

2021 ◽  
Author(s):  
Yang Yang ◽  
Minqiang Zhou ◽  
Ting Wang ◽  
Bo Yao ◽  
Pengfei Han ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Human Activities ◽  
North China ◽  
Terrestrial Ecosystem ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Boundary Layer Height ◽  
The Mean ◽  
The Impact ◽  
First Time

Abstract. Atmospheric CO2 mole fractions are observed at Beijing (BJ), Xianghe (XH), and Xinglong (XL) in North China using the Picarro G2301 Cavity Ring-Down Spectroscopy instruments. The measurement system is described comprehensively for the first time. The geo-distances among these three sites are within 200 km, but they have very different surrounding environments: BJ is inside the megacity; XH is in the suburban area; XL is in the countryside on a mountain. The mean and standard deviation of CO2 mole fractions at BJ, XH, and XL between October 2018 and September 2019 are 448.4 ± 12.8 ppm, 436.0 ± 9.2 ppm and 420.6 ± 8.2 ppm, respectively. The seasonal variations of CO2 at these three sites are similar, with a maximum in winter and a minimum in summer, which is dominated by the terrestrial ecosystem. However, the seasonal variations of CO2 at BJ and XH are more affected by human activities as compared to XL. By using CO2 at XL as the background, CO2 enhancements are observed simultaneously at BJ and XH. The diurnal variations of CO2 are driven by the boundary layer height, photosynthesis and human activities at BJ, XH and XL. Moreover, we address the impact of the wind on the CO2 mole fractions at BJ and XL. This study provides an insight into the spatial and temporal variations of CO2 mole fractions in North China.

Synthesis of Geometric Primary Circles of Externally Meshed Skew-Axes Gears

1989 ◽  
Author(s):  
V. Abadjiev ◽  
D. Petrova
Keyword(s):  
Constant Speed ◽  
Mutual Position ◽  
Speed Ratio ◽  
First Time

Abstract What are considered are geometric primary circles of gears which transform rotations between fixed skewed axes with a constant speed ratio. These imaginary circles differ from the pitch ones of the gears with parallel or intersecting axes. It seems they are used succeessfully for the first time as a start point in designing hyperbolic gears. Both the diameters and the mutual position parameters of the geometric primary circles are needed when gear over-alls and mounting distances as well as teeth geometry are determined.

Trust, Ethnicity and Integrity in East Africa: Experimental Evidence from Kenya and Tanzania

2017 ◽  
Vol 2 (1) ◽  
pp. 88-123 ◽  
Author(s):  
Dominic Burbidge ◽  
Nic Cheeseman
Keyword(s):  
Ethnic Diversity ◽  
Negative Impact ◽  
Common Knowledge ◽  
Individual Level ◽  
Trust Games ◽  
Negative Effect ◽  
Experimental Games ◽  
The Individual ◽  
The Impact ◽  
First Time

AbstractPolitical economy comparisons of Kenya and Tanzania have often found the political salience of ethnicity to be far higher in the former than the latter, with a negative impact on intercommunal trust. This difference has tended to be explained on the basis of the different kinds of leadership that the two countries experienced after independence. However, these findings have typically been demonstrated using aggregate or survey data. This paper assesses the salience of ethnicity at the individual level for the first time, deploying monetized two-round trust games in urban Kenya and Tanzania. The experimental games isolate the comparative impact of common knowledge of ethnicity and integrity among a quasi-random selection of 486 citizens. Verifying previous findings, we observe higher levels of trust and trustworthiness in Tanzania as compared with Kenya. Further, in comparison with Kenya, any shared knowledge of ethnic identities in Tanzania leads players to transfer fewer resources, while common knowledge that both players are “honest” led to higher transfers there than in Kenya. These results provide robust evidence of higher levels of trust in Tanzania, and of the negative effect in that country of common knowledge of ethnicity on levels of cooperation. The findings demonstrate the way in which political context can shape the impact of ethnic diversity, and encourage further experimental research that looks at the intersubjective dynamics of social cooperation.

scholarly journals Acetamiprid Affects Destruxins Production but Its Accumulation in Metarhizium sp. Spores Increases Infection Ability of Fungi

Toxins ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 587
Author(s):  
Monika Nowak ◽  
Przemysław Bernat ◽  
Julia Mrozińska ◽  
Sylwia Różalska
Keyword(s):  
Secondary Metabolism ◽  
Pest Control ◽  
Entomopathogenic Fungi ◽  
Negative Impact ◽  
Fungal Growth ◽  
Growth Environment ◽  
Anthropogenic Pollutants ◽  
Control Factors ◽  
Natural Pest Control ◽  
First Time

Metarhizium sp. are entomopathogenic fungi that inhabit the soil environment. Together, they act as natural pest control factors. In the natural environment, they come into contact with various anthropogenic pollutants, and sometimes, they are used together and interchangeably with chemical insecticides (e.g., neonicotinoids) for pest control. In most cases, the compatibility of entomopathogens with insecticides has been determined; however, the influence of these compounds on the metabolism of entomopathogenic fungi has not yet been studied. Secondary metabolites are very important factors that influence the fitness of the producers, playing important roles in the ability of these pathogens to successfully parasitize insects. In this study, for the first time, we focus on whether the insecticide present in the fungal growth environment affects secondary metabolism in fungi. The research revealed that acetamiprid at concentrations from 5 to 50 mg L−1 did not inhibit the growth of all tested Metarhizium sp.; however, it reduced the level of 19 produced destruxins in direct proportion to the dosage used. Furthermore, it was shown that acetamiprid accumulates not only in plant or animal tissues, but also in fungal cells. Despite the negative impact of acetamiprid on secondary metabolism, it was proofed to accumulate in Metarhizium spores, which appeared to have a stronger infectious potential against mealworm Tenebrio molitor, in comparison to the insecticide or the biological agent alone.

Savonius Wind Turbine Performances on Wind Concentrator

2017 ◽  
Vol 8 (1) ◽  
pp. 376
Author(s):  
Dygku. Asmanissa Awg. Osman ◽  
Norzanah Rosmin ◽  
Nor Shahida Hasan ◽  
Baharruddin Ishak ◽  
Aede Hatib Mustaamal@Jamal ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Electrical Power ◽  
Vertical Axis ◽  
Angular Speed ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Air Compressor ◽  
Tip Speed Ratio ◽  
Savonius Wind Turbine ◽  
Air Streams

The air streams from the outlet of an air compressor can be used to generate electricity. For instance, if a micro-sized Vertical-Axis Wind-Turbine (VAWT) is installed towards the airflow, some amount of electricity can be generated before being stored in a battery bank. The research’s objectives are to design, fabricate and analyze the performance of Helical Savonius VAWT blade rotors, which is tested with and without using a wind concentrator. The Helical Savonius VAWT is tested at 0 cm without the concentrator, whereas the blade rotor is tested at concave-blade position when using the concentrator. The blade and the wind concentrator designs were based on the dimensions and the constant airflow of the air compressor. The findings suggested that the blade produced its best performance when tested using wind concentrator at concave-blade position in terms of angular speed (<em>ω</em>), tip speed ratio (<em>TSR</em>) and the generated electrical power (<em>P</em><em><sub>E</sub></em>). The findings concluded that the addition of wind concentrator increases the airflow which then provided better performances on the blades.

scholarly journals Spaceborne GNSS-R Observation of Global Lake Level: First Results from the TechDemoSat-1 Mission

2019 ◽  
Vol 11 (12) ◽  
pp. 1438 ◽  
Author(s):  
Liwen Xu ◽  
Wei Wan ◽  
Xiuwan Chen ◽  
Siyu Zhu ◽  
Baojian Liu ◽  
...  
Keyword(s):  
Satellite System ◽  
Temporal Variations ◽  
Strong Correlations ◽  
Lake Levels ◽  
The Caspian Sea ◽  
First Results ◽  
The Uk ◽  
Global Navigation Satellite ◽  
Inland Water Bodies ◽  
First Time

Spaceborne global navigation satellite system reflectometry (GNSS-R) data collected by the UK TechDemoSat-1 (TDS-1) satellite is applied to retrieve global lake levels for the first time. Lake levels of 351 global lakes (area greater than 500 km2 and elevation lower than 3000 m each) are estimated using TDS-1 Level 1b data over 2015–2017. Strong correlations (overall R2 greater than 0.95) are observed among lake levels derived from TDS-1 and other altimetry satellites such as CryoSat-2, Jason, and Envisat (the latter two are collected by Hydroweb), although with large root-mean-square error (RMSE) (tens of meters) mainly due to the fact that TDS-1 is not dedicated for altimetry measuring purpose. Examples of the Caspian Sea and the Poyang Lake show consistent spatial and temporal variations between TDS-1 and other data sources. The results in this paper provide supportive information for further application of GNSS-R constellations to measure altimetry of inland water bodies.

scholarly journals Kinetics of Biotic and Abiotic CO Production during the Initial Phase of Biowaste Composting

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5451
Author(s):  
Sylwia Stegenta-Dąbrowska ◽  
Karolina Sobieraj ◽  
Jacek A. Koziel ◽  
Jerzy Bieniek ◽  
Andrzej Białowiec
Keyword(s):  
Initial Phase ◽  
Occupational Safety ◽  
Negative Impact ◽  
Order Kinetic ◽  
K Value ◽  
Thermochemical Process ◽  
Full Study ◽  
Order Kinetic Model ◽  
First Time ◽  
Kinetics Of

Knowledge of kinetic parameters of CO production during biowaste composting is significantly important for the prediction of its course and estimation of total gas quantity. This allows increasing the control of the process, to minimize its negative impact on the environment and to protect the occupational safety of employees exposed to CO in the biowaste composting plant. For the first time, a full study of the influence of temperature and biowaste sterilization on the kinetics of CO production is presented. The lab-scale experiments used a mixture of green waste, dairy cattle manure, and sawdust in two variants: sterilized and non-sterilized samples. The process was carried out in controlled temperature reactors with measuring the concentrations of CO, O2, and CO2 every 12 h.CO production and k value increased with temperature. However, higher CO production was observed in biotic conditions between 10~50 °C, suggesting the biotic CO formation and 1st-order kinetics. The abiotic (thermochemical) process was more efficiently generating CO above 50 °C, described with a 0-order kinetic model. Additionally, the rate constant (k) value of CO production under biotic conditions was increasing up to a temperature of 60 °C, above which a slight decrease in CO production rate was observed at 70 °C. The presented results are the basis for further studies focused on the feasibility of (1) the mitigation and (2) valorization of CO production during the biowaste biostabilization are warranted.

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