Changes in the quality parameters of seedling tea due to height and frequency of mechanical harvesting

Quality parameters of black tea change due to the use of a mechanical harvester, varying plucking round lengths and plucking heights. Compared with hand plucking, mechanically harvested teas have inferior quality as measured by volatile flavour compounds, theaflavins and caffeine. Similarly, longer plucking rounds produced inferior teas compared with shorter rounds. Raising mechanical plucking height by 2 cm from the previous plucking height caused less quality deterioration than increasing the height by 1 cm irrespective of plucking rounds.     

Fully Coupled 3-D Conjugate Heat Transfer Algorithm for Borehole Heat Exchanger Performance Prediction

Quantitative three-dimensional prediction of the thermal performance of a vertical borehole heat exchanger (BHE) in a ground-source heat pump installation is sought. As BHE installation exhibits exceptionally disparate characteristic length scales, an alternative formation-fluid-thermal fully coupled algorithm is derived to quickly predict the 3-D temperature distributions. The time scale of the steady prediction is of order minutes. This simulation capability can be readily coupled to long-time (order months) unsteady simulation of an entire wellbore field. Algorithm prediction is validated by comparison with data from an instrumented commercial installation for a unique BHE conduit design, followed by illustrative design optimization or variation assessments.     

Design of Managed Aquifer Recharge for Agricultural and Ecological Water Supply Assessed Through Numerical Modeling

The Walla Walla Basin, in Eastern Oregon and Washington, USA, faces challenges in sustaining an agricultural water supply while maintaining sufficient flow in the Walla Walla River for endangered fish populations. Minimum summer river flow of 0.71 m³/s is required, forcing irrigators to substitute groundwater from a declining aquifer for lost surface water diversion. Managed Aquifer Recharge (MAR) was initiated in 2004 attempting to restore groundwater levels and improve agricultural viability. The Integrated Water Flow Model (IWFM) was used to compute surface and shallow groundwater conditions in the basin under water management scenarios with varying water use, MAR, and allowable minimum river flow. A mean increase of 1.5 m of groundwater elevation, or 1.5 % of total aquifer storage, was predicted over the model area when comparing maximum MAR and no MAR scenarios where minimum river flow was increased from current level. When comparing these scenarios a 53 % greater summer flow in springs was predicted with the use of MAR. Results indicate MAR can supplement irrigation supply while stabilizing groundwater levels and increasing summer streamflow. Potential increase in long-term groundwater storage is limited by the high transmissivity of the aquifer material. Increased MAR caused increased groundwater discharge through springs and stream beds, benefiting aquatic habitat rather than building long-term aquifer storage. Judicious siting of recharge basins may be a means of increasing the effectiveness of MAR in the basin.     

Needed: Early-term adjustments for Lake Erie phosphorus target loads to address western basin cyanobacterial blooms

For Lake Erie, it is already time to revise the phosphorus target loads set to address the problem of cyanobacterial blooms in the Western Basin. Current targets were proposed by the Annex 4 task group in 2015, adopted by U.S. and Canadian governments in 2016, and set as objectives of domestic action plans in 2017. These targets, applicable to all spring discharges below the 90th percentile, set a maximum load for both total phosphorus (TP) and dissolved reactive phosphorus (DRP) equivalent to 60% of their 2008 spring loads. This essentially mandates 40% reductions in both particulate phosphorus (PP) and DRP loading relative to 2008 loads. These targets do not explicitly incorporate the difference in bioavailability between DRP (~100% bioavailable) and PP (~25% bioavailable). From 2008 to 2017, DRP comprised 24% of the spring TP load and over half (~56%) of the total bioavailable phosphorus (TBAP) load, while PP comprised 76% of the TP load but only ~44% of the TBAP load. Subsequent deposition of PP in the estuarine and nearshore zones further reduces its significance in bloom development. By ignoring differences in bioavailability, the current targets provide no guidance for choosing among practices based on their relative effectiveness in reducing DRP or PP and their combined reductions in TBAP loading. Current targets place more emphasis on PP than needed to efficiently reach targeted cyanobacterial bloom reductions. To clarify appropriate management approaches and lead to greater success in reducing cyanobacterial blooms, target loads should be based on TBAP.     

Noise-shaping sense amplifier for MRAM cross-point arrays

A sensing technique using a voltage-mode architecture, noise-shaping modulator, and digital filter (a counter) is presented for use with cross-point MRAM arrays and magnetic tunnel junction memory cells. The presented technique eliminates the need for precision components, the use of calibrations, and reduces the effects of power supply noise. To obviate the effects of cell-to-cell variations in the array, a digital self-referencing scheme using the counter is presented. Measured experimental results in a 180-nm CMOS process indicate an RMS sensing noise of 20 /spl mu/V for a 5-/spl mu/s sense time. Further increases in sense time are shown to increase the signal-to-noise ratio. The current used by the sense amplifier and counter was measured as 10 /spl mu/A when running at 100 MHz or 10 mA when 1000 sense amplifiers are used with a memory subarray having 1000 bitlines.     

We have always been transgenic

This dialogue concerns the nature of ethical responsibility in contemporary art practice, and its relation to questions of creativity; the role of writing in shaping the perception of transgenic art and related practices; and the problems that may be associated with trusting artists to act with integrity in the unchartered waters of their enthusiastic engagement with genetic technologies.     

The utility of event-based knowledge elicitation

The purpose of this investigation was to describe and evaluate an event-based knowledge elicitation technique. With this approach experts are provided with deliberate and controlled job situations, allowing investigation of specific task aspects and the comparison of expert responses. For this effort a videotape was developed showing an instructor pilot and student conducting a training mission. Various job situations were depicted in the video to gather information pertinent to understanding team situational awareness. The videotape was shown to 10 instructors and 10 student aviators in the community, and responses to the videotape were collected using a questionnaire at predetermined stop points. Consistent with expectations, the results showed that more experienced respondents (i.e., instructors) identified a richer database of cues and were more likely than students to identify strategies for responding to the situations depicted, providing some empirical evidence for the validity of the event-based technique. This method may serve as a useful knowledge elicitation technique, especially in the later stages of a job analysis when focused information is sought.     

RESIDENCE TIMES OF TWO- AND THREE-COMPONENT MIXTURES IN CASCADING ROTARY DRYERS

The residence times of the components of two- and three-component mixtures of fine (195 µm), coarse (1315 µm) and very coarse (5040 µm) sands were measured in a pilot-scale cascading rotary dryer. The effects of mixture composition and air velocity (0-5.4 m s^-1) were determined. With no air flowing through the drum, the residence times of the individual components were almost the same as that of the overall mixture. Increasing the gas velocity caused a large decrease in residence time. In contrast, particle size had very little effect. The spread of residence times increased with air velocity, peaking between 2 and 4 m s^-1; composition had very little effect on the spread. The residence time of the overall mixture could be calculated using the particle transport model of Matchett and Baker if both the modified drag coefficient Φ_d and the particle Reynolds number Re_p were based on the superficial air velocity and the mass-average particle diameter.