scholarly journals Technical note: Dimensioning IRGA gas sampling system: laboratory and field experiments

2015 ◽  
Vol 8 (10) ◽  
pp. 10735-10754
Author(s):  
M. Aubinet ◽  
L. Joly ◽  
D. Loustau ◽  
A. De Ligne ◽  
H. Chopin ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Field Experiments ◽  
Technical Note ◽  
Limiting Factor ◽  
Strong Impact ◽  
Sampling System ◽  
Gas Sampling ◽  
Eddy Covariance Measurements ◽  
Set Up ◽  
The Impact

Abstract. Both laboratory and field experiments were carried out in order to define suitable configuration ranges for the gas sampling systems (GSS) of infrared gas analyzers (IRGA) used in eddy covariance measurements. In the laboratory, an original dynamic calibration bench was developed in order to test the frequency attenuation and pressure drop generated by filters. In the field, IRGAs equipped with different filters or different rain cups were installed and run and the real frequency response of the complete set-up was tested. The main results are that: – Filters may have a strong impact on the pressure drop in the GSS and this impact increases with flow rate. – On the contrary, no impact of the tested filters on cut off frequency was found, GSS with and without filters presenting similar cut off frequencies. – The main limiting factor of cut off frequency in the field was found to be the rain cup design. In addition, the impact of this design on pressure drop was also found noteworthy.

scholarly journals Dimensioning IRGA gas sampling systems: laboratory and field experiments

2016 ◽  
Vol 9 (3) ◽  
pp. 1361-1367 ◽  
Author(s):  
Marc Aubinet ◽  
Lilian Joly ◽  
Denis Loustau ◽  
Anne De Ligne ◽  
Henri Chopin ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Field Experiments ◽  
Limiting Factor ◽  
Dynamic Calibration ◽  
Strong Impact ◽  
Gas Sampling ◽  
Real Frequency ◽  
Sampling Systems ◽  
The Impact ◽  
Original Dynamic

Abstract. Both laboratory and field experiments were carried out in order to define suitable configuration ranges for the gas sampling systems (GSSs) of infrared gas analyzers (IRGAs) used in eddy covariance measurements.In the laboratory, an original dynamic calibration bench was developed in order to test the frequency attenuation and pressure drop generated by filters. In the field, three IRGAs of the same type equipped with different filters or different rain caps were installed and run and the real frequency response of the complete setup was tested. The main results are as follows. – Filters may have a strong impact on the pressure drop in the GSS and this impact increases with flow rate. – Conversely, no impact of the tested filters on cut-off frequency was found, GSSs with and without filters presenting similar cut-off frequencies. – The main limiting factor of cut-off frequency in the field was found to be the rain cap design. In addition, the impact of this design on pressure drop was also found to be noteworthy.

Can We Engineer Better Multistage Horizontal Completions? Evidence of the Importance of Near-wellbore Fracture Geometry from Theory, Lab and Field Experiments

2015 ◽  
Author(s):  
B.. Lecampion ◽  
J.. Desroches ◽  
X.. Weng ◽  
J.. Burghardt ◽  
J.E.. E. Brown
Keyword(s):  
Pressure Drop ◽  
Field Experiments ◽  
Horizontal Wells ◽  
Fracture Plane ◽  
Hydraulic Fractures ◽  
Multiple Fractures ◽  
Fracture Geometry ◽  
Complex Fracture ◽  
Limited Entry ◽  
The Impact

Abstract There is accepted evidence that multistage fracturing of horizontal wells in shale reservoirs results in significant production variation from perforation cluster to perforation cluster. Typically, between 30 and 40% of the clusters do not significantly contribute to production while the majority of the production comes from only 20 to 30% of the clusters. Based on numerical modeling, laboratory and field experiments, we investigate the process of simultaneously initiating and propagating several hydraulic fractures. In particular, we clarify the interplay between the impact of perforation friction and stress shadow on the stability of the propagation of multiple fractures. We show that a sufficiently large perforation pressure drop (limited entry) can counteract the stress interference between different growing fractures. We also discuss the robustness of the current design practices (cluster location, limited entry) in the presence of characterized stress heterogeneities. Laboratory experiments highlight the complexity of the fracture geometry in the near-wellbore region. Such complex fracture path results from local stress perturbations around the well and the perforations, as well as the rock fabric. The fracture complexity (i.e., the merging of multiple fractures and the reorientation towards the preferred far-field fracture plane) induces a strong nonlinear pressure drop on a scale of a few meters. Single entry field experiments in horizontal wells show that this near-wellbore effect is larger in magnitude than perforation friction and is highly variable between clusters, without being predictable. Through a combination of field measurements and modeling, we show that such variability results in a very heterogeneous slurry rate distribution; and therefore, proppant intake between clusters during a stage, even in the presence of limited entry techniques. We also note that the estimated distribution of proppant intake between clusters appears similar to published production log data. We conclude that understanding and accounting for the complex fracture geometry in the near-wellbore is an important missing link to better engineer horizontal well multistage completions.

Vulnerability of Patagonian planktonic copepods to fluctuations in temperature and UV radiation

Crustaceana ◽  
2014 ◽  
Vol 87 (3) ◽  
pp. 291-304 ◽  
Author(s):  
Patricia Elizabeth Garcia ◽  
María C. Dieguez
Keyword(s):  
South America ◽  
Effect Of Temperature ◽  
Limiting Factor ◽  
South American ◽  
The Andes ◽  
High Solar Radiation ◽  
Set Up ◽  
Solar Radiation Exposure ◽  
Increasing Temperature ◽  
The Impact

The aim of this investigation is to address the impact of fluctuations in temperature and ultraviolet radiation (UVR) on three species of South American copepods, Boeckella antiqua, B. gracilis and B. brevicaudata. These copepods are cold stenotherm and occur in high latitude lakes of South America and in mountain lakes in the Andes. The forecast scenarios for climate change in southern South America anticipate raising temperature and UVR levels. These changes may have the potential to impact high altitude and latitude ecosystems, including lakes and their cold adapted biota, such as those in Patagonia. Laboratory experiments, consisting of 10 day and 2 day incubations, were set up to analyse copepod mortality in relation with: (i) temperature, and (ii) the combined effect of temperature (5, 8, 12, 16, 20°C) and UV-B dose (61, 194 and 324 J m−2). The results obtained showed up that temperature is a limiting factor for B. brevicaudata that did not survive above 12°C. B. antiqua and B. gracilis withstood the temperature range although their mortality was higher at 12-16°C. The survivorship of these copepod species to radiation was found to depend on the UV-B dose, resulting in higher mortality at the highest UV-B dose. Overall, at least one Boeckella species showed an acute sensitivity to increasing temperature, and the three species studied proved tolerant to the UV-B experimental exposure. The survivorship patterns observed in Boeckella species reflect clearly their adaptation to high solar radiation exposure and to temperate to cold environmental conditions.

scholarly journals Impact of Postgraduate Student Internships During the COVID-19 Pandemic in China

2022 ◽  
Vol 12 ◽  
Author(s):  
Wenyi Zhang ◽  
Xiaozhong Lu ◽  
Derong Kang ◽  
Jiaxin Quan
Keyword(s):  
Mental Health ◽  
Strong Impact ◽  
Mild Depression ◽  
Psychological Counseling ◽  
Postgraduate Students ◽  
Employment Conditions ◽  
Set Up ◽  
Internship Programs ◽  
And Control ◽  
The Impact

To understand the impact of the COVID-19 pandemic on postgraduate students’ internships in China, 911 students from different regions of China were surveyed through online questionnaires. Among the postgraduate students surveyed, 48.51% of which believed that the pandemic had its greatest impact on colleagues interaction, and 59.60% believed that the pandemic had a strong impact on practical skills. In total, 31.8% of postgraduate internship programs were impacted by COVID-19. The proportions of respondents having severe, moderate, and mild anxiety levels were 1.42%, 4.72%, and 15.92%, respectively; and the rates of severe, moderate, and mild depression were 1.64%, 10.86%, and 21.84%, respectively. ANOVA found that major, degree type, and degree of impact of the pandemic on colleague interactions and improved practical abilities all affected postgraduate mental health. The findings suggest that the mental health of postgraduate students should be monitored during a pandemic, and targeted psychological counseling should be offered. Postgraduate internships should be emphasized as to ensure a smooth internship process during a pandemic period. Psychological counseling and assistance should be provided to those whose internships were affected by the pandemic, and programs should be set up to aid postgraduate students in adapting to the new internship and employment conditions brought on by the “new normal” of pandemic prevention and control.

Erodibility of loess depending on its weathering: field experiments

2021 ◽  
Author(s):  
Jan Vojtisek ◽  
Jiri Bruthans
Keyword(s):  
Erosion Rate ◽  
Field Experiments ◽  
Ground Surface ◽  
Drill Hole ◽  
Original Structure ◽  
Strong Impact ◽  
Surface Zone ◽  
Rill Erosion ◽  
Initial Shape ◽  
The Impact

<p>Piping is an erosion process in which cracks and macropores extend into channels with a diameter of cm or more. The study of loess erosion is important because loess covers about ten percent of the continents surface and is susceptible to piping, formation of gullies and intense erosion of agricultural soil. Study was done in Střeleč quarry (Czech Republic), where a several meters thick loess cover occurs in the upper part, sometimes with cracks and macropores. Rill erosion and piping conduits are formed in the loess cover and this makes it an ideal place for field experiments and observations. The erosion rate of the loess by water trickle at quarry face, erosion of the drill hole and erosion under the impact of the droplets were studied. The erosion rate of the rills was measured using long screws screwed directly into the rill. Rapid erosion occurred within first tens of centimeters from original ground surface in the zone where the loess structure was disintegrated by frost or wetting-drying cycles. Below this zone, the erosion rate was much lower, and it ceased with time as rill deepened. Small piping conduits developed rapidly by pouring water into small desiccation cracks on the loess surface. On the other hand, the dril hole did not expand into piping conduit in deeper zone of loess. Moisture content of small loess blocks have strong impact on final degree of erosion. While dry blocks began to disintegrate relatively quickly into incoherent material, the pre-wetted samples did not disintegrated and more or less kept their initial shape. This shows that slaking is responsible for disintegration of small dry blocks on loess surface. While the surface zone of the loess is highly erodible by flowing water, probably due to the loss of its original structure, the loess in the deeper zone is far less erodible in the quarry and even pre-formed conduit (dril hole) do not develop into larger conduit.</p><p> </p><p>Many thanks to the management of Střeleč Quarry for enabling of the field documentation and experiments. The research was supported by Charles University Grant Agency (GAUK #1292119).</p>

scholarly journals The Impact of Brand Image and Customer Commitment on Loyalty: An Empirical Study of Automobile Sector

2013 ◽  
Vol 5 (4) ◽  
pp. 181-193 ◽  
Author(s):  
Yu-TeTu Yu-TeTu ◽  
Tan-Kui Hsu .
Keyword(s):  
Brand Image ◽  
Relevant Literature ◽  
Operating Cost ◽  
Initial Study ◽  
Strong Impact ◽  
Corporate Brand ◽  
Customer Commitment ◽  
Set Up ◽  
The Impact

Corporate brand image has been assessed as an important antecedent of customer commitment and loyalty. Corporate brands help companies achieving higher performance, such as sales. A poor brand image will lead to disaster, and lose customers. Marketing exists to deliver more value to satisfy customers as well as build a long-term and mutually profitability relationship with customers. If a firm’s products or services do not satisfy or meet the customer’s needs and wants, all the strategies are insufficient. With loyal customers, companies can have higher market share and reduce the operating cost. This initial study was from relevant literature, then set up research structure and hypotheses. Survey was employed, and respondents were collected from automobile sector in Taiwan. There were 170 usable questionnaires to analyze normality, convergent and discriminant validities, and SEM model by PASW 18 and AMOS 18.0. The research found that corporate brand image significantly affects customer commitment and loyalty, and customer commitment has strong impact on customer loyalty for the sample. Therefore, firms need to specifically focus on a long-term and mutually profitability relationship with a customer and create loyalty as competitive advantages in the markets.

Prediction of root damaging during mechanical shaking of fruit trees

2014 ◽  
Vol 10 (1) ◽  
pp. 1-15
Author(s):  
Z. Láng
Keyword(s):  
Field Experiments ◽  
Calculated Data ◽  
Fruit Trees ◽  
List Type ◽  
Structure Model ◽  
Root Damage ◽  
Set Up ◽  
Simple Tree ◽  
The Given ◽  
Cherry Trees

The possible effect of shaker harvest on root damage of 10-year-old cherry trees was studied on a simple tree structure model. The model was composed of elastic trunk and rigid main roots, the ends of which were connected to the surrounding soil via springs and dumping elements. Equations were set up to be able to calculate the relation between shaking height on the trunk and strain in the roots. To get the data for root break and their elongation at different shaking heights on the trunk, laboratory and field experiments were carried out on cherry trees and on their roots. Having evaluated the measured and calculated data it could be concluded that root damage is to be expected even at 3.6% strain and the risk of it increases with increased trunk amplitudes, i.e.with the decrease of shaking heightat smaller stem diameters (i.e. in younger plantation), andif the unbalanced mass of the shaker machine is too large for the given tree size.

When Do Psychopathic Traits Affect Cooperative Behavior?: An Iterated Prisoner's Dilemma Experimental Study

2020 ◽  
Author(s):  
M Testori ◽  
M Kempf ◽  
RB Hoyle ◽  
Hedwig Eisenbarth
Keyword(s):  
Prisoner's Dilemma ◽  
Cooperative Behavior ◽  
Prisoner’S Dilemma ◽  
Selection Procedure ◽  
Psychopathic Traits ◽  
Strong Impact ◽  
Iterated Prisoner's Dilemma ◽  
Human Decision ◽  
The Impact ◽  
Iterated Prisoner’S Dilemma

© 2019 Hogrefe Publishing. Personality traits have been long recognized to have a strong impact on human decision-making. In this study, a sample of 314 participants took part in an online game to investigate the impact of psychopathic traits on cooperative behavior in an iterated Prisoner's dilemma game. We found that disinhibition decreased the maintenance of cooperation in successive plays, but had no effect on moving toward cooperation after a previous defection or on the overall level of cooperation over rounds. Furthermore, our results underline the crucial importance of a good model selection procedure, showing how a poor choice of statistical model can provide misleading results.

INFLUENCE OF THE DIFFERENT SOIL PREPARATION METHODS ON THE PEA YIELD

2018 ◽  
pp. 16-20
Author(s):  
А. М. Grebennikov ◽  
А. S. Frid ◽  
V. P. Belobrov ◽  
V. А. Isaev ◽  
V. М. Garmashоv ◽  
...  
Keyword(s):  
Field Experiments ◽  
Morphological Properties ◽  
Mineral Fertilizers ◽  
First Year ◽  
Zero Tillage ◽  
Preparation Methods ◽  
Soil Preparation ◽  
Multifactor Analysis ◽  
The Impact ◽  
Central Chernozem

The article assesses the relationships between the morphological properties of agrochernozems and yield of peas on the plots, experience with different methods of basic treatment (moldboard plowing at the depth of 20 - 22, 25 - 27 and 14 - 16 cm, moldboard plowing to a depth of 14 - 16 cm, combined midwater moldboard, mid-water subsurface, surface to a depth of 6 - 8 cm and zero tillage) is inherent in V.V. Dokuchaev Research Institute of Agriculture of the Central Black Earth strip, in the fall of 2014. The research was conducted in 2015 - 2016, with the application of mineral fertilizers (N60Р60К60) and unfertilized background. The highest pea yields in the fertilized as the background, and without the use of fertilizers was observed in dumping plowing and especially in the variant with deep moldboard plowing, which creates in comparison with other ways of handling the best conditions for the growth and development of peas. The lowest yield of pea was obtained with zero processing. Apparently legalistic migrational-mizelial agrochernozems the Central Chernozem zone of minimum tillage in the cultivation of peas are not effective, what is evident already in the first year after the laying of experience with different basic treatments. As shown by the results of applying multifactor analysis of variance studied the mapping properties of the soil can have the same significant impact on the yield of agricultural crops, as options for the field experiments aimed at assessing the impact of various treatments on yield.

The effect of brain vitalization activity on dementia incidence in elderly at Budi Luhur Nursing Home of Yogyakarta, Kasongan, Bantul

2020 ◽  
Vol 1 (3) ◽  
pp. 43-50
Author(s):  
Firstyono Miftahul Aziz ◽  
Suratini Suratini
Keyword(s):  
Nursing Home ◽  
The Elderly ◽  
Control Group ◽  
P Value ◽  
Sampling System ◽  
Randomized Sampling ◽  
Care For The Elderly ◽  
Dementia Incidence ◽  
The Family ◽  
The Impact

For some people, dementia is considered as a disease that is common in elderly, regardless the impact of dementia. Taking care for the elderly with dementia brings stress for the family. It can cause and increase the family burden. Brain vitalization gymnastics is one of the methods to improve memory. The study aims to investigate the effect of brain vitalization activity on dementia incidence in elderly at Budi Luhur Nursing Home of Yogyakarta. The study used Quasi Experimental with Pretest-Posttest control group and randomized sampling system. The samples were taken randomly as many as 26 respondents and were divided into two groups namely 13 respondents of experimental group and 13 respondents of control group. The statistical test used Wilcoxon Match Pairs Test. The result showed that Wilcoxon Match pairs test obtained p value 0,003, which is smaller than 0,005. There is an effect of brain vitalization activity on dementia incidence in elderly at Budi Luhur Nursing Home of Yogyakarta

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