Forced convection heat transfer to water with air injection through on porous heated wall of a rectangular duct

Imperial Users onl

Letter, 1969 June 9, from Earl Grant to Eva Jessye

2 pages, Grant is an old friend. George Gershwin is mentioned

‘Summative’ and ‘Formative’: Confused by the assessment terms?

The terms ‘formative’ and ‘summative’ when linked to assessment can cause confusion. Should these terms be dropped? Should we move on from them? This paper argues that it is the common shortening of the full and meaningful terms, ‘assessment for formative purposes’ and ‘assessment for summative purposes’ that contributes to a confusion over assessments, information and methods, particularly for pre-service teachers and those with less teaching experience. By being well-informed about both purpose and assessment activity, teachers will have greater clarity in understanding, communication and practice regarding these important and useful concepts

Confidence in assessment decisions when using ICT

The central question addressed in this paper is: How can teachers and schools have confidence in their assessment decisions when using information communication technologies (ICT)? The answer centres on what makes quality assessment. Assessing and evaluating children’s achievement and progress is critical to development of sound curriculum programmes that focus on student outcomes. With the increasing use of ICT in schools and classrooms for a range of assessment purposes such as recording, data analysis and online activities, teachers and school leaders must be assessment capable in order to make informed decisions about assessment design, selection and modification that utilises ICT. Based on examining assessment purpose and the three principles of quality assessment (validity, reliability and manageability), this paper offers guidelines for classroom teachers, those with responsibility for student achievement and those who lead ICT policy and practice in schools to be critical consumers of ICT-based assessment tools, strategies and evidence. Vignettes of assessment practice using ICT are used to illustrate sound school and classroom practices in relation to validity, reliability, and manageability. Drawing from the work of assessment writers such as Crooks, Sutton, and Darr, the guidelines will assist teachers in the effective use of ICT for both formal and informal information gathering as well as for analysis and interpretation of information for summative and formative purposes. This knowledge is needed to underpin teacher confidence in their assessment decisions when using ICT towards ‘best fit’ for purpose

4R\u27s of Irrigation Management

This fact sheet introduces the concept of the 4\u27R\u27s of irrigation management and discusses some factors to consider in each of the 4R\u27s, right source, right rate. right time, and right place

Combined Forced and Free Convection in Stratified and Unstratified Flows

The laminar, steady, horizontal flow past a hot or cold two-dimensional body is examined; the fluid is unbounded, diffusive, and viscous. The presence of significant ambient stable temperature (or density) stratification, or significant buoyancy-induced convection, or both, is considered. A detailed understanding of the fundamental structure of such flows is obtained by developing effective analytical and numerical solution procedures. Chapter 2: This chapter considers the general problem of stably stratified, Oseen flow at large distances upstream and downstream of a body which is represented as a line sink of horizontal or vertical momentum, or as a line heat source or heat dipole. The analysis is focused on the general properties of the horizontal velocity component, as well as on explicit calculation of the horizontal velocity profiles and disturbance streamfunction fields for varying degrees of stratification. For stable stratifications, the flow fields for all four types of singularities exhibit the common feature of multiple recirculating rotors of finite thicknesses, which leads to an alternating jet structure. both upstream and downstream for the horizontal velocity component and to lee-waves in the overall flow. Self-similar formulae for the velocity, temperature, and pressure at very large distances upstream and downstream are also derived and compared with the Oseen solutions Chapter 3: The simultaneous forced and free convection flow of a neutrally- or stably-stratified fluid past a hot or cold horizontal flat plate is investigated by numerically solving the full equations of motion and thermal energy subject only to the Boussinesq approximation. The solutions span the parameter ranges 10 &#8804; Re &#8804; 100, 0.1 &#8804; Pr &#8804; 10, -2.215 &#8804; Gr/Re5/2 &#8804; +2.215, and O &#8804; Ri &#8804; 6.325, where Re, Pr, Gr, and Ri are based on the overall plate length ℓ and the ambient free stream fluid properties evaluated at the plate level. For all degrees of stratification a hot plate causes an acceleration of the boundary flow near the plate surface relative to the corresponding forced convection flow, thereby increasing both the local skin friction and heat transfer coefficients. On the other hand, the boundary flow adjacent to a cold plate is decelerated and the local skin friction and heat transfer rate are decreased. This deceleration effect is enhanced by either further cooling or increasing the amount of ambient stratification, Ri, leading to boundary-layer separation in some cases. When the effect of the ambient stratification dominates that of local heating or cooling, the boundary-layer displacement increases for decreasing Ri, due to the buoyancy restoring force lessening, thus diminishing the drag. The dimunition in the drag, for the same decrease in Ri, lessens (increases) by slightly heating (cooling) the plate. When the effect of local heating or cooling dominates that of the ambient stratification, the drag is diminished by increasing Ri. A wave-structure exists only for stably-stratified fluids, with the amplitudes and wavelengths of the waves being decreased for increasing Ri.</p

Measuring and Building Soil Health

This fact sheet provide facts about soil health and will help land managers understand what soil health is, how to measure it, and how to potentially build it on their soils

Considerations for Crop Rotation from Alfalfa to Corn

The importance of rotating out of a declining alfalfa stand is well established. As the alfalfa stand ages, forage yield and quality decline, while weed, insect, and disease pressures increase. Terminating the stand and growing one or more other crops for several (2–3) years allows a grower to press the reset button on a piece of ground. These years of growing another crop will result in more productive alfalfa when a new stand is planted again