Search results for "Laboratory experiment"

Manual packing and soil reuse effects on determination of saturated hydraulic conductivity of a loam soil

2022

Abstract Performing laboratory measurement of saturated hydraulic conductivity, Ks, of sieved soil is important for many scientific purposes such as testing theories and methods to determine Ks. A given soil mass can be used only once or it can be reused after a previous use. Little is known on the dependence of the Ks measurements on both the applied packing method and the reuse of the same soil mass. This lack of knowledge makes comparisons among different investigations more or less uncertain. Four packing methods were tested on an initially dry loam soil by measuring Ks with the simplified falling head (SFH) technique. The four methods differed by the used compacting procedure (dropping…

Revisiting the Trade-off Between Risk and Incentives: The Shocking Effect of Random Shocks?

2019

Despite its central role in the theory of incentives, empirical evidence of a trade-off between risk and incentives remains scarce. We reexamine this trade-off in a workplace lab environment and find that, in line with theory, principals increase fixed pay while lowering performance pay when the relationship between effort and output is noisier. Unexpectedly, agents produce substantially more in the noisy environment than in the baseline despite weaker incentives. In addition, principals’ earnings are significantly higher in the noisy environment. We show that these findings can be accounted for when agents maximize a non-CARA utility function or when they exhibit loss aversion. Data and t…

Thermal inertia modeling for soil surface water content estimation: A laboratory experiment

2012

We are proposing a new method for estimating soil surface water content from thermal inertia distributions retrieved from visible–near infrared (VISNIR)and thermal infrared (TIR) images. A drying experiment was conducted on three fi ne-textured soils while acquiring multispectral VIS-NIR and TIR images. Simultaneous measurements of soil water content and thermal inertia were conducted by the thermogravimetric method and the heat pulse technique, respectively. Direct measurements were used to test the thermal inertia approach proposed by Murray and Verhoef that requires only knowledge of soil porosity and can be easily inverted to derive soil water content from thermal inertia. For the three…

The effects of virtuality level on task-related collaborative behaviors: The mediating role of team trust

2013

This study aims to analyze the mediating role of team trust in the relationship between virtuality level and task-related collaborative behaviors. Three types of task-related collaborative behaviors were studied, namely team coordination, team cooperation, and team information exchange. Drawing upon theory and research on virtual teams and trust, we hypothesized that team trust partially mediated the effects of virtuality level on team coordination, team cooperation, and team information exchange. A laboratory experiment was carried out with 65 four-person teams randomly assigned to three communication media with different virtuality levels (face-to-face, video conference and computer-media…

Investigating face-to-face and virtual teamwork over time: When does early task conflict trigger relationship conflict?

2012

North Carolina State UniversityPast research has indicated that early task consict can trigger subsequent relationshipconsict during teamwork. The current study examines conditions that may exacerbateor attenuate this relationship. SpeciÞcally, this study examines the moderating role ofprocess consict and communication medium on the link between task consict andrelationship consict over time. A longitudinal laboratory experiment was carried outcomparing 22 face-to-face (FTF) groups, 22 videoconference (VC) groups, and 22synchronous computer mediated (i.e., OchatO) communication (CMC) groups workingon a complex team task over a period of 1 month. Results highlight the robust insuenceof early…

Measurement of the Convective Heat-Transfer Coefficient

2014

We propose an experiment for investigating how objects cool down toward the thermal equilibrium with its surrounding through convection. We describe the time dependence of the temperature difference of the cooling object and the environment with an exponential decay function. By measuring the thermal constant tau, we determine the convective heat-transfer coefficient, which is a characteristic constant of the convection system.

Turbulent Flow Structures For Different Roughness Conditions of Channel Walls: Results of experimental investigation in laboratory flumes

2013

Do Tengmalm's owls see vole scent marks visible in ultraviolet light?

1997

Scent markings (urine and faeces) of small mammals are visible in ultraviolet (UV) light. Diurnal kestrels, Falco tinnunculususe them as a cue to find areas of food abundance. We studied whether vole-eating, nocturnal Tengmalm's owls, Aegolius funereuscan see vole scent marks using UV-vision. In a laboratory experiment, 14 young (less than 6 months old) and 14 adult (more than 6 months old) owls were individually given a choice between four adjacent arenas: (1) an arena with vole urine and faeces in UV light; (2) an arena with vole urine and faeces in visible light; (3) a clean arena in UV light; and (4) a clean arena in visible light. Owls did not prefer any of the four arenas. Our results…

UV reflecting vole scent marks attract a passerine, the great grey shrike Lanius excubitor

2002

Diurnal raptors have been shown to use ultraviolet vision and UV-reflecting vole scent marks to find suitable hunting areas. We studied if a passerine species, the great grey shrike Lanius excubitor that uses voles as its primary food, may also detect prey-patches in the same way. We conducted a laboratory experiment with ten shrikes. Each individual shrike had four options to choose from: (1) scent marks with UV light, (2) scent marks without UV light, (3) clean arena with UV light, and (4) clean arena without UV light. The birds preferred the scent-marked arena with UV light as measured by the number of scans and the time spent above it. Therefore, we suggest that great grey shrike probab…

Why Real Leisure Really Matters: Incentive Effects on Real Effort in the Laboratory

2013

On-the-job leisure is a pervasive feature of the modern workplace. We studied its impact on work performance in a laboratory experiment by either allowing or restricting Internet access. We used a 2×2 experimental design in which subjects completing real-effort work tasks could earn cash according to either individual- or team-production incentive schemes. Under team pay, production levels were significantly lower when Internet browsing was available than when it was not. Under individual pay, however, no differences in production levels were observed between the treatment in which Internet was available and the treatment in which it was not. In line with standard incentive theory, individu…