Effect of Lemna minor population density on bioelectric parameters of electro-biosystems.

2021 ◽  
Vol 6 (4) ◽  
pp. 195-200
Author(s):  
Iryna Rusyn ◽  
◽  
Vasil Dyachok ◽  
Keyword(s):  
Population Density ◽  
Lemna Minor ◽  
Open Circuit ◽  
Bioelectric Potential ◽  
Minor Population ◽  
Positive Effect ◽  
Load Conditions

The article presents a study of the influence of Lemna minor population density on the bioelectric potential and current of model electro-biosystems in the laboratory сonditions using 500 and 1000 Ω resistors and in the open circuit. The positive effect of increasing the density of duckweed plants populations from 60 to 120 fronds/ml on the growth of bioelectric parameters of model electro-biosystems under load conditions and without resistors was revealed. Increasing the amount of duckweed biomass is a factor of enhancing the efficiency of electro-biosystems based on L. minor.

scholarly journals Comparative Study of Dual PM Vernier Machines

2021 ◽  
Vol 12 (1) ◽  
pp. 12
Author(s):  
Huan Qu ◽  
Zi Qiang Zhu ◽  
Toru Matsuura ◽  
Dusan Ivanovic ◽  
Takashi Kato ◽  
...  
Keyword(s):  
Comparative Study ◽  
Open Circuit ◽  
Torque Density ◽  
Halbach Array ◽  
Higher Power ◽  
Pole Structure ◽  
Consequent Pole ◽  
Torque Ripples ◽  
Two Machines ◽  
Load Conditions

In this paper, two types of dual permanent magnet (PM) machines, i.e., stator slot dual-PM (SSDPM) machine and split-tooth dual-PM (STDPM) machine, are investigated and compared. Both machines have consequent pole structure with Halbach array PMs. Their difference lies in the position of stator PM. The SSDPM machine has Halbach array PMs in the stator slots, while the STDPM machine has PMs between the split teeth. Torque characteristics, i.e., average torques and torque ripples, of different slot/pole number combinations of the two machines are compared. The 24 stator slots/20 rotor slots/4 armature pole pair (24S20R4Pa) SSDPM machine with distributed windings and the 24 stator slots/10 rotor slots/4 armature pole pair (12S20R4Pa) STDPM machine with concentrated windings are compared under both open-circuit and on-load conditions. The results show that the SSDPM machine is more competitive by delivering higher torque density and higher power density.

The rhizosphere of an aquatic plant (Lemna minor)

1969 ◽  
Vol 15 (8) ◽  
pp. 964-966 ◽  
Author(s):  
R. A. Coler ◽  
H. B. Gunner
Keyword(s):  
Population Density ◽  
Carrying Capacity ◽  
Aquatic Plant ◽  
Lemna Minor ◽  
Fold Increase ◽  
Inert Surfaces

Dominant epiphytes colonizing the surface of Lemna minor were identified and enumerated. The distribution of these organisms compared to populations on inert surfaces at depths 0, [Formula: see text], 1, 2, 4 and 8 in. revealed greater than a 100-fold increase in population density. This enhanced carrying capacity of the plant diminished with depth.

scholarly journals PENGARUH GLOBALISASI KEPADATAN PENDUDUK DAN PERTUMBUHAN EKONOMI TERHADAP DEGRADASI LINGKUNGAN DI INDONESIA

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Safriwan Safriwan ◽  
Idris Idris
Keyword(s):  
Population Density ◽  
Environmental Degradation ◽  
Research Result ◽  
Short Term ◽  
Method Error ◽  
Negative Effect ◽  
Economic Institute ◽  
Carbon Project ◽  
Positive Effect

Abstract : The study describes the effects on globalization population density andeconomic growth on environmental degradation in Indonesia. This research uses a timeseries data from year 1971 - 2017, with method Error Correction Model (ECM). Datasources from Global Carbon Project, KOF Swiss Economic Institute, and WorldBank. Research result explain that (1) Globalization in long term has a insignificantpositive effect on environmental degradation in Indonesia, but short term globalizationhas a insignificant negative effect on environmental degradation in Indonesia (2)Population density in long term has a significant positive , and short term has ainsignificant positive effect on environmental degradation in Indonesia (3) Economicgrowth in long and short term has a significant positive effect on environmentaldegradation in Indonesia.Keywords : Environmental Degradation, Globalization Population Density AndEconomic Growth.

scholarly journals V-belt transmissions of agricultural machines

2021 ◽  
Vol 1 (3) ◽  
pp. 31-36
Author(s):  
N.P. Balovnev ◽  
◽  
Y.I. Brovkina ◽  
L.A. Dmitrieva ◽  
◽  
...  
Keyword(s):  
Shock Loading ◽  
Open Circuit ◽  
Operating Conditions ◽  
Special Method ◽  
Agricultural Machinery ◽  
Belt Drives ◽  
Regulatory Documents ◽  
Guide Roller ◽  
Positive Effect ◽  
Agricultural Machines

The article is devoted to the analysis of design features and operating conditions of V-belt trans-missions of agricultural machinery. When designing these gears, it is recommended to give prefer-ence to gears made according to an open circuit or with a tension roller located outside the belt con-tour, to avoid cross and semi-cross gears, as well as multi-pulley gears with crossing shaft axles. To make the wider use of more progressive types of belts. It was shown that the features of V-belt transmissions of agricultural machinery require clarification of the methods for calculating trans-missions with progressive types of V-belts and automatic belt tensioning methods. It was noted that special attention should be paid to transmissions with multi-profile belts, which calculation has not been sufficiently reflected in domestic regulatory documents. The advantages of such belts are es-pecially noticeable under variable and shock loading. Based on the analysis, the recommendations for clarifying the calculation of belt drives with multi-profile belts were given. Analytical dependencies are proposed for determining the value of the nominal power transmitted by one belt (stream) of a multi-profile belt, allowing automation of the calculation of V-belt transmissions of agricultural machinery. For gears with a tension or guide roller that add an extra (sometimes reverse) bend of the belt, it is proposed to determine the coeffi-cient taking into account different degrees of bending on the pulleys according to a graph built tak-ing into account the linear hypothesis of summation of damages. It is recommended to calculate gears with spring-loaded tensioning rollers and design tensioning devices for such transmissions using a special method that takes into account the belt tensioning method. At the same time, the required value of the pre-tension of the belt can be significantly re-duced, which will have a positive effect on its resource, without losing the traction capacity of the transmission itself. Expressions are given for finding the value of the pre-tension of belts, both for gears with tension due to the elasticity of the belt, and for gears with spring-loaded tension rollers. Conclusions and directions for further research are formulated.

scholarly journals Improving efficiency and lowering operating costs of evaporative cooling

2021 ◽  
Vol 338 ◽  
pp. 01027
Author(s):  
Jan Taler ◽  
Bartosz Jagieła ◽  
Magdalena Jaremkiewicz
Keyword(s):  
Electricity Consumption ◽  
Open Circuit ◽  
Dew Point ◽  
Operating Costs ◽  
Water Evaporation ◽  
Total Water ◽  
Point Temperature ◽  
Dew Point Temperature ◽  
Adiabatic Cooling ◽  
Positive Effect

Cooling towers, or so-called evaporation towers, use the natural effect of water evaporation to dissipate heat in industrial and comfort installations. Water, until it changes its state of aggregation, from liquid to gas, consumes energy (2.257 kJ/kg). By consuming this energy, it lowers the air temperature to the wet-bulb temperature, thanks to which the medium can be cooled below the ambient temperature. Evaporative solutions are characterized by continuous water evaporation (approx. 1.5% of the total water flow) and low electricity consumption (high EER). Evaporative (adiabatic) cooling also has a positive effect on the reduction of electricity consumption of cooled machines. Lowering the relative humidity (RH) by approx. 2% lowers the wet-bulb temperature by approx. 0.5°C, which increases the efficiency of the tower, operating in an open circuit, expressed in kW, by approx. 5%, while reducing water consumption and treatment costs. The use of the M-Cycle (Maisotsenko cycle) to lower the temperature of the wet thermometer to the dew point temperature will reduce operating costs and increase the efficiency of cooled machines.

The influence of low-frequency laser emission on phyto- and zooplankton productivity properties

2020 ◽  
Vol 12 (2) ◽  
pp. 196-201
Author(s):  
Lidiia Khuda ◽  
Larysa Cheban ◽  
Oleksii Khudyi
Keyword(s):  
Population Density ◽  
Catalase Activity ◽  
Laser Emission ◽  
Low Frequency ◽  
Positive Influence ◽  
The Other ◽  
Control Group ◽  
Microalgae Biomass ◽  
Frequency Laser ◽  
Positive Effect

We studied the possibility of using low frequency laser emission to improve production properties of feed hydrobionts, in particular microalgae Desmodesmus armatus and Daphnia magna, which are highly applied in aquaculture. It was shown that low-frequency laser emission with the wavelength 650 nm has a positive influence on production properties of both phyto- and zooplankton. In 24 hours the biomass of irradiated D. armatus was 25% larger than non-irradiated one. Meanwhile, application λ 420 and 530 nm did not show credible accumulation of microalgae biomass. If it comes to daphnia, positive dynamic in population density enlarging was observed only since 5-7th day of cultivation, depending on emission exposition. Differences in low-frequency laser emission with λ 420 and 530 efficacy on D. magna production properties were observed while using different exposition. Thus, maximal culture density was observed when λ 420 nm for 90 s and λ 650 nm for 60 s were applied. Longer irradiation with red laser did not have positive effect. It was established that in daphnia tissues, which were influenced by λ 420 nm laser emission, TBA-active products were accumulating more. Meanwhile, for daphnias, which were irradiated with red laser, TBA amount was not different from the control group one. Catalase activity increased while applying λ 650 nm laser emission. On the other hand, λ 420 nm did not cause credible increasing of catalase activity in comparison with control group. Taking received results about photobiological effects of low-frequency laser emission on D. armatus and D. magna into consideration, both biomasses enlargement during co-cultivation can be obtained if wavelength 650 nm is used.

The effect of offering concentrate supplement to twin- and triplet-bearing ewes grazing a 60 mm herbage sward height on lamb birth weight, heat production and post-natal growth

2009 ◽  
Vol 147 (5) ◽  
pp. 613-624 ◽  
Author(s):  
J. I. KERSLAKE ◽  
P. R. KENYON ◽  
K. J. STAFFORD ◽  
S. T. MORRIS ◽  
P. C. H. MOREL
Keyword(s):  
Birth Weight ◽  
Heat Production ◽  
Open Circuit ◽  
Gamma Glutamyl Transferase ◽  
Blood Samples ◽  
Positive Effects ◽  
Sward Height ◽  
Herbage Intake ◽  
Glutamyl Transferase ◽  
Positive Effect

SUMMARYThe current study investigated the effect of offering concentrate supplement to ewes in late pregnancy on twin- and triplet-born lamb heat production at 24–36 h old and performance from birth until lactation day 94 (L94). Twin- (n=40) and triplet-bearing (n=28) ewes were grazed on a 60 mm sward height from day 70 of pregnancy (P70) until L94. From P100, half of the ewes from each litter size were offered 400 g/ewe/day of concentrate sheep pellets. Ewe liveweight and body condition were recorded on P50, 100, 130, 135 and 140. Ewe blood samples were also collected on P130, 135 and 140, and ewe herbage intake was estimated from P133–136 using the n-alkane method. Lamb measurements included liveweight and body size at birth, production of heat using indirect open-circuit calorimetry at 24–36 h old and liveweight at L94. Blood samples were also collected from lambs at 24–36 h old and directly before and after calorimetry measurements. While estimates of ewe herbage intake suggested that substitution of herbage for concentrate did not occur, offering concentrate supplement failed to improve ewe liveweight gain, or birth weight of lambs. Offering concentrate supplement, however, did have a positive effect (P<0·05) on the maximal amount of heat a triplet-born lamb can produce on a per kg of body weight basis (concentrate 21±1·3 W/kg, non-concentrate 17±0·6 W/kg). It also had a positive effect (P<0·05) on lamb square-root-transformed plasma gamma-glutamyl transferase (GGT) concentrations, an indicator of colostrum uptake (concentrate 46±3·1 U/l, non-concentrate 38±2·9 U/l). Irrespective of lamb birth rank, offering concentrate supplement had a positive effect (P<0·01) on liveweight gain per day from birth until L94 (concentrate 261±5·7 g/day, non-concentrate 239±5·8 g/day), although there was no effect on the total weight of lamb reared/ewe. Supplementation with concentrate resulted in triplet-born lambs that produced more heat which may have positive effects on the ability of the newborn lamb to deal with cold stress and potentially its survival. Offering concentrate supplement also produced greater lamb growth in twin- and triplet-born lambs.

scholarly journals The importance of intraspecific diversity on duckweed growth with and without salt stress

2021 ◽  
Author(s):  
Sofia Julia van Moorsel
Keyword(s):  
Salt Stress ◽  
Growth Rates ◽  
Lemna Minor ◽  
Freshwater Ecosystems ◽  
Intraspecific Diversity ◽  
Natural Community ◽  
Experimental Mesocosms ◽  
Freshwater Plants ◽  
Stressful Environments ◽  
Positive Effect

The pollution of freshwater ecosystems is threatening freshwater plant species diversity worldwide. Freshwater plants, such as duckweed (Lemna minor), are potentially sensitive to novel stressful environments. To test if intraspecific diversity could increase resistance to stressful environments, I used seven L. minor populations and assessed their growth rates in the absence and presence of moderate salt stress across an intraspecific diversity gradient.I grew the populations (ecotypes) of L. minor over five months in 92 experimental mesocosms in a glasshouse either in ecotype monocultures or in polyculture with either one or three conspecific ecotypes (23 unique compositions). The experiment was conducted in semi-natural conditions, including a natural community of algae and microbes. After assessing the duckweed growth rate in unperturbed conditions, the cultures were subjected to moderate salt stress (50mM NaCl) for several weeks. Population abundances were assessed weekly, both on the ecotype level and the whole-population level.Throughout the experiment, the ecotypes differed in their growth rates, the fastest growing at twice the rate of others. Whether the ecotypes grew in monoculture or in polyculture with other conspecifics further shaped the ecotype growth rates. Ecotype polycultures showed higher abundances towards the end of the experiment, indicating that over time, as the environment deteriorated, intraspecific diversity gained in importance. These findings show that intraspecific variation in growth rates can translate to a positive effect of intraspecific diversity on whole-population abundance. Exposure of L. minor to moderate salt levels did not significantly impact growth rates.

scholarly journals Utjecaj pripravka na bazi fluopirama i tekućega pilećeg stajnjaka na nematode korijenovih kvržica (Meloidogyne spp.) u nasadu mrkve

Poljoprivreda ◽  
2019 ◽  
Vol 25 (2) ◽  
pp. 25-30
Author(s):  
Mirjana Brmež ◽  
Brigita Popović ◽  
Dinka Grubišić ◽  
Tamara Siber ◽  
Emilija Raspudić ◽  
...  
Keyword(s):  
Community Structure ◽  
Population Density ◽  
Block Design ◽  
Chicken Manure ◽  
Random Block ◽  
Meloidogyne Spp ◽  
Random Block Design ◽  
Set Up ◽  
Nematode Biodiversity ◽  
Positive Effect

The aim of this study was to investigate the nematocidal effect of the preparations based on fluopyram (pesticide) and liquid chicken manure (natural amendment) on the population density of the root-knot nematodes, Meloidogyne spp. in carrot crops. The field experiment was set up in four treatments: control (C), fluopyram (FLU), fluopyram and liquid chicken manure (FLU+LCM) and liquid chicken manure (LCM) by a random block design in four replicates. Population density of Meloidogyne spp. juveniles varied between the treatments, and the number of Meloidogyne spp. was significantly decreased in all treatments with fluopyram (FLU and FLU+LCM). All amended treatments (FLU, FLU+LCM, LCM) decreased galling of the roots and had a positive effect on carrot yield. The population of Meloidogyne spp. juveniles increased with the plant growth, regardless of the treatments applied. Fluopyram negatively affected the biodiversity indicating greater disturbance for the nematode community structure in the soil. It can be concluded that fluopyram and liquid chicken manure have nematicidal potential, while liquid chicken manure maintained or enhanced nematode biodiversity.

Homeownership, Neighbourhood Characteristics and Children’s Positive Behaviours among Low- and Moderate-income Households

Urban Studies ◽  
2012 ◽  
Vol 49 (16) ◽  
pp. 3545-3563 ◽  
Author(s):  
Michal Grinstein-Weiss ◽  
Clinton Key ◽  
Yeong Hun Yeo ◽  
Joan Yoo ◽  
Krista Holub ◽  
...  
Keyword(s):  
Population Density ◽  
Propensity Score ◽  
Selection Bias ◽  
Hierarchical Regression ◽  
Significant Positive Effect ◽  
Propensity Score Weighting ◽  
The Us ◽  
Neighbourhood Characteristics ◽  
Using Data ◽  
Positive Effect

Using data on low-to-moderate-income households in the US Community Advantage Program survey, this paper examines homeownership, neighbourhood characteristics and the interaction between the two on the positive behaviour of children from low- and moderate-income households. To control for potential selection bias and endogeneity problems, propensity score weighting and hierarchical regression are employed to tease apart the effects of homeownership, neighbourhood characteristics and their interaction on child positive behaviour. No effect is found of homeownership or neighbourhood characteristics on children’s positive behaviour when the interaction between the two is not included in the model. However, homeownership was found to have a stronger positive effect on children’s positive behaviour as neighbourhood population density increases and, at approximately 4000 persons per square mile (approximate population density of San Diego, CA), homeownership has a significant positive effect on children’s overall scores on the positive behaviour scale.

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