Effects of Changes in Surface Water Regime and/or Land Use on the Vertical Distribution of Water Available for Wetland Vegetation: Dynamic Model of the Zone of Aeration (Part 1 of Completion Report for Project A-023-ARK)

A mathematical model by Green, simulating one-dimensional vertical ground-water movement in unsaturated soils of the prairie region of Kansas, has been adapted for use in a wetlands environment typified by the wetlands forest of Eastern Arkansas. The model consists of two second-order, non-linear, partial differential equations and an algorithm for their numerical solution. The original model was extended to include functions for seasonal changes in transpiration and for drainage of excess precipitation. Before the addition of the two functions, the model reliability was limited to one growth season

Effects of Changes in Surface Water Regime and/or Land Use on the Vertical Distribution of Water Available for Wetland Vegetation: Dynamic Model of the Zone of Aeration (Appendix to Part 1 of Completion Report for Project A-023-ARK)

Appendix to Part 1 of Completion Report for Project A-023-AR

Portable Environmental Data Logger and Sensor

An instrumentation and recording package and several transducers were constructed and used to collect data on the environmental parameters thought to affect wetland vegetation growth and reproduction. These parameters were temperature, humidity, wind velocity, depth of water table, and amount of surface water. The data were collected four times a day and recorded on a magnetic cassette tape that could record for as long as 90 days. The tapes were read and the data were converted to engineering units by a microcomputer-based instrument constructed for that purpose

Effects of Changes in Surface Water Regime and/or Land Use on the Vertical Distribution of Water Available for Wetland Vegetation: Portable Environmental Data Logger and Sensors (Part II of Completion Report for Project A-023-ARK)

An instrumentation and recording package and several transducers were constructed and used to collect data on the environmental parameters thought to affect wetland vegetation growth and reproduction. These parameters were temperature, humidity, wind velocity, depth of water table, and amount of surface water. The data were collected four times a day and recorded on a magnetic cassette tape that could record for as long as 90 days. The tapes were read and the data were converted to engineering units by a microcomputer-based instrument constructed for that purpose

Dynamic Model of the Zone of Aeration

A mathematical model by Green (1), simulating one-dimensional vertical ground-water movement in unsaturated soils of the prairie region of Kansas, has been adapted for use in a wetlands environment typified by the wetlands forest of Eastern Arkansas. The model consists of two second-order, non-linear, partial differential equations and an algorithm for their numerical solution. The original model was extended to include functions for seasonal changes in transpiration and for drainage of excess precipitation. Before the addition of the two functions, the model reliability was limited to one growth season. With the mathematical model presented in this work it is possible to study interactions between hydrologic changes and the long term vegetative changes. The model potentially is a versatile management tool which could be used to help predict the environmental impact of proposed flood control projects

The role of tool geometry in process damped milling

The complex interaction between machining structural systems and the cutting process results in machining instability, so called chatter. In some milling scenarios, process damping is a useful phenomenon that can be exploited to mitigate chatter and hence improve productivity. In the present study, experiments are performed to evaluate the performance of process damped milling considering different tool geometries (edge radius, rake and relief angles and variable helix/pitch). The results clearly indicate that variable helix/pitch angles most significantly increase process damping performance. Additionally, increased cutting edge radius moderately improves process damping performance, while rake and relief angles have a smaller and closely coupled effect

Magnetorheological landing gear: 2. Validation using experimental data

Aircraft landing gears are subjected to a wide range of excitation conditions with conflicting damping requirements. A novel solution to this problem is to implement semi-active damping using magnetorheological (MR) fluids. In part 1 of this contribution, a methodology was developed that enables the geometry of a flow mode MR valve to be optimized within the constraints of an existing passive landing gear. The device was designed to be optimal in terms of its impact performance, which was demonstrated using numerical simulations of the complete landing gear system. To perform the simulations, assumptions were made regarding some of the parameters used in the MR shock strut model. In particular, the MR fluid's yield stress, viscosity, and bulk modulus properties were not known accurately. Therefore, the present contribution aims to validate these parameters experimentally, via the manufacture and testing of an MR shock strut. The gas exponent, which is used to model the shock strut's nonlinear stiffness, is also investigated. In general, it is shown that MR fluid property data at high shear rates are required in order to accurately predict performance prior to device manufacture. Furthermore, the study illustrates how fluid compressibility can have a significant influence on the device time constant, and hence on potential control strategies

Dynamic pricing and benchmarking in AirBnB

AbstractSince Airbnb opened in 2008, renting private accommodation has evolved into a strong market presence worldwide. Recent research has focused on whether this new supply will negatively affect hotel performance. Studies mainly focus on market performance and professionalization, but there is an absence of research regarding available knowledge and experience of pricing considerations. This research focuses on pricing decisions for individual apartment rental, examining the relationship between Airbnb pricing and knowledge transfer from related fields, such as hotel revenue management, benchmarking and online travel agencies. The primary research was conducted through semi-structured interviews with industry professionals, complemented by data examples that show the relevance of individual pricing. Findings confirm that applied revenue management and benchmarking concepts can enhance a host’s booking performances. Motivation and pricing experience amongst professional/non-professional hosts differ. Benchmarking professionals identify that market research becomes a key activity for running a successful business