Feasibility of reduced gravity experiments involving quiescent, uniform particle cloud combustion

The study of combustible particle clouds is of fundamental scientific interest as well as a practical concern. The principal scientific interests are the characteristic combustion properties, especially flame structure, propagation rates, stability limits, and the effects of stoichiometry, particle type, transport phenomena, and nonadiabatic processes on these properties. The feasibility tests for the particle cloud combustion experiment (PCCE) were performed in reduced gravity in the following stages: (1) fuel particles were mixed into cloud form inside a flammability tube; (2) when the concentration of particles in the cloud was sufficiently uniform, the particle motion was allowed to decay toward quiescence; (3) an igniter was energized which both opened one end of the tube and ignited the suspended particle cloud; and (4) the flame proceeded down the tube length, with its position and characteristic features being photographed by high-speed cameras. Gravitational settling and buoyancy effects were minimized because of the reduced gravity enviroment in the NASA Lewis drop towers and aircraft. Feasibility was shown as quasi-steady flame propagation which was observed for fuel-rich mixtures. Of greatest scientific interest is the finding that for near-stoichiometric mixtures, a new mode of flame propagation was observed, now called a chattering flame. These flames did not propagate steadily through the tube. Chattering modes of flame propagation are not expected to display extinction limits that are the same as those for acoustically undisturbed, uniform, quiescent clouds. A low concentration of fuel particles, uniformly distributed in a volume, may not be flammable but may be made flammable, as was observed, through induced segregation processes. A theory was developed which showed that chattering flame propagation was controlled by radiation from combustion products which heated the successive discrete laminae sufficiently to cause autoignition

When daily planning improves employee performance: the importance of planning type, engagement, and interruptions

Does planning for a particular workday help employees perform better than on other days they fail to plan? We investigate this question by identifying two distinct types of daily work planning to explain why and when planning improves employees’ daily performance. The first type is time management planning (TMP)—creating task lists, prioritizing tasks, and determining how and when to perform them. We propose that TMP enhances employees’ performance by increasing their work engagement, but that these positive effects are weakened when employees face many interruptions in their day. The second type is contingent planning (CP) in which employees anticipate possible interruptions in their work and plan for them. We propose that CP helps employees stay engaged and perform well despite frequent interruptions. We investigate these hypotheses using a two-week experience-sampling study. Our findings indicate that TMP’s positive effects are conditioned upon the amount of interruptions, but CP has positive effects that are not influenced by the level of interruptions. Through this study, we help inform workers of the different planning methods they can use to increase their daily motivation and performance in dynamic work environments

A Statistical Approach to Improve the Residential Life in UB

This project aims at improving the residential life in the University of Bridgeport , with a special emphasis on North Hall and South Hall. With this motivation, this study depicts the facilities that are provided to the UB students and analyzes the problems that residents are facing in the dormitories. A survey has been conducted among the residents using the study published by Serwint, J. R., Feigelman, S., Dumont-Driscoll, M., Collins, R., Zhan, M., & Kittredge, D. After the data collection, the data have been analyzed to provide customized solutions for the improvement of the student residential life. Resident satisfaction was defined as satisfied or not satisfied on a survey sheet

Pulse detonation engines and components thereof

A pulse detonation engine comprises a primary air inlet; a primary air plenum located in fluid communication with the primary air inlet; a secondary air inlet; a secondary air plenum located in fluid communication with the secondary air inlet, wherein the secondary air plenum is substantially isolated from the primary air plenum; a pulse detonation combustor comprising a pulse detonation chamber, wherein the pulse detonation chamber is located downstream of and in fluid communication with the primary air plenum; a coaxial liner surrounding the pulse detonation combustor defining a cooling plenum, wherein the cooling plenum is in fluid communication with the secondary air plenum; an axial turbine assembly located downstream of and in fluid communication with the pulse detonation combustor and the cooling plenum; and a housing encasing the primary air plenum, the secondary air plenum, the pulse detonation combustor, the coaxial liner, and the axial turbine assembly

A novel flow battery: a lead acid battery based on an electrolyte with soluble lead(II) Part IX. Electrode and electrolyte conditioning with hydrogen peroxide

This is the author's manuscript version. The version of record is available via DOI: 10.1016/j.jpowsour.2009.10.109Available online:13 November 2009Extended cycling of a soluble lead acid battery can lead to problems due to an imbalance in the coulombic efficiency leading to deposits of Pb and PbO2 on the electrodes. Periodic addition of hydrogen peroxide to the electrolyte of the soluble lead acid flow battery largely overcomes several operational problems seen during extended cycling, using a 10 cm × 10 cm parallel plate flow cell. It is shown that this treatment greatly extends the number of cycles that can be achieved with a reasonable energy-, voltage-, and charge efficiency of 54–66%, 71%, and 77–91%.DTI Technology Programm

Age and trust as moderators in the relation between procedural justice and turnover: a large-scale longitudinal study

Item does not contain fulltextThe current study investigated the moderating roles of age and trust in the relation of procedural justice with turnover. It was expected that the relation between procedural justice and turnover was weaker for older workers and those with high prior trust in their leader. Older workers are better at regulating their emotions, and focus more on positive aspects of their relationships with others, and therefore react less intensely to unfair treatment. Moreover, people with high trust are more likely to attribute unfair treatment to circumstances instead of deliberate intention than people with low trust. Finally, we expected a three-way interaction between age, trust, and procedural justice in relation to turnover, where older workers with high trust would have less strong reactions than younger workers and older workers with low trust. Results from a three-wave longitudinal survey among 1,597 Dutch employees indeed revealed significant interactions between trust and procedural justice in relation to turnover. Furthermore, the three-way interaction was significant, with negative relations for younger workers, but a non-significant relation was found for older workers with low trust. Contrary to expectations, negative relations were found between procedural justice and turnover for older workers with high trust

DEVELOPMENT AND VALIDATION OF A SPECIAL PURPOSE SENSOR AND PROCESSOR SYSTEM TO CALCULATE EQUILIBRIUM MOISTURE CONTENT OF WOOD

Percent Moisture Content (MC %) of wood is defined to be the weight of the moisture in the wood divided by the weight of the dry wood times 100%. Equilibrium Moisture Content (EMC), moisture content at environmental equilibrium is a very important metric affecting the performance of wood in many applications. For best performance in many applications, the goal is to maintain this value between 6% and 8%. EMC value is a function of the temperature and the relative humidity of the surrounding air of wood. It is very important to maintain this value while processing, storing or finishing the wood. This thesis develops a special purpose sensor and processor system to be implemented as a small hand-held device used to sense, calculate and display the value of EMC of wood depending on surrounding environmental conditions. Wood processing industry personnel would use the hand-held EMC calculating and display device to prevent many potential problems that can show significant affect on the performance of wood. The design of the EMC device requires the use of sensors to obtain the required inputs of temperature and relative humidity. In this thesis various market available sensors are compared and appropriate sensor is chosen for the design. The calculation of EMC requires many arithmetic operations with stringent precision requirements. Various arithmetic algorithms and systems are compared in terms of meeting required arithmetic functionality, precision requirements, and silicon implementation area and gate count, and a suitable choice is made. The resulting processor organization and design is coded in VHDL using the Xilinx ISE 6.2.03i tool set. The design is synthesized, validated via VHDL virtual prototype simulation, and implemented to a Xilinx Spartan2E FPGA for experimental hardware prototype testing and evaluation. It is tested over various ranges of temperature and relative humidity. Comparison of experimentally calculated EMC values with the theoretical values of EMC derived for corresponding temperature and relative humidity points resulted in validation of the EMC processor architecture, functional performance and arithmetic precision requirements

Current-voltage characteristics of TaSi2/Si and MOS devices using Labview

Analyses of current-voltage (LV) characteristics of Schottky Barrier Diodes (Tantalum Suicide) and Metal Oxide Semiconductor (MOS) Devices, using LabVIEWTM, has been presented here. LabVIEWTMTM, a graphical program development application, has been used to program a computer-driven Keithley Source Measure Unit (SMU) for device characterization. The SMU, which can be used as a Source Voltage - Measure Current as well as Source Current - Measure Voltage instrument, is used in the Source Voltage -Measure Current mode in this study. A General Purpose Interface Bus (GPIB) IEEE 488.2 has been used to interface the SMU with LabVIEWTMTM. LabVIEWTM has been successfully implemented to obtain the current-voltage characteristics of semiconductor devices, such as TaSi2 /Si and MOS structures. Based on this characterization, factors such as the barrier height for TaSi2 /Si and current conduction mechanisms in MOS device structures have been evaluated