An Experimental Investigation of the Air-Side Convective Heat Transfer Coefficient on Wire and Tube Refrigerator Condenser Coils

This thesis presents the results of an experimental investigation of the convective airside heat transfer from wire and tube condensers. The ftrst law of thermodynamics is applied to the "refrigerant", water in this investigation, flowing through the tubes in order to determine the total heat loss from the condenser. The test section is 910 mm (36 in) wide by 300 mm (12 in) tall; thus the coil is tested in an essentially inftnite stream. During the course of the experiments, the influence of the free stream air velocity ranging from 0.15 rn/s to 2.0 rn/s (0.49 ftls to 6.56 ftls) is established. The angle of attack, n, was varied from - 40 degrees to 40 degrees with the air flow always normal to the tubes ('11= 1t/2) and varied from -20 degrees to 20 degrees with the air flow normal to the wires ('II = 0). A method for , calculating view factors and the radiation heat transfer for wire and tube condensers is derived. The effect of the length of the coil is measered at 0 and -5??angle of attack. In addition, the influence of the ftn efftciency on the heat transfer is investigated and accounted for in the deftnition of the heat transfer coefftcient. The heat transfer data in the inertia dominated regime (Richardson number less than 0.0013) are correlated assuming NUcoil = t(Re, n, 'II)' g( S: ) with the Reynolds number based on the wire diameter. The range of Reynolds numbers covered is 15.7 < Rew < 207.5. The ranges of coil geometric parameters (nondimensionlized by dividing by the wire diameter) covered in this study are: 3.022 < nondimensional tube diameter < 5.134, 18.84 < nondimensional tube spacing < 40.94,2.819 < nondimensional wire spacing < 4.427,53.80 < nondimensional tube length< 143.6, and 207.2 < nondimensional wire length < 500.2. The function is represented by tl(a)??Reh (a) for 'II = 0 and h(a).Rei4 (a) for'll=1t/2. Approximately 1700 tests were performed in this investigation using seven different coils. The ftnal correlation is capable of predicting the data with 2cr equal to 16.7% for Ri < 0.0013. A limited natural convection study is also presented.Air Conditioning and Refrigeration Center Project 4

Parameters of CO2 bands near 3.6 microns

The intensities, widths, and positions of lines of three CO2 bands near 2750/cm were determined. The results are in general agreement with other measured and estimated values

Comment with the Copyright Office Regarding a Proposed Exemption Under 17 U.S.C. Section 1201 for Software Security Research (Class 25)

Professor Candice Hoke, Cleveland State University, and others (Douglas W. Jones, University of Iowa; Professor Deirdre Mulligan, University of California, Berkeley; Professor Vern Paxson, University of California, Berkeley;Professor Pamela Samuelson, University of California, Berkeley; Bruce Schneier Erik Stallman, Center for Democracy & Technology (CDT); comment addressing Proposed Class 25: Software Security Research and an exemption for software security research in order to promote the active research and testing efforts necessary to keep pace with evolving cybersecurity risks. Software and related access controls are increasingly embedded in a wide range of systems, from consumer goods to medical devices to infrastructure to industrial equipment. This trend carries tremendous opportunities, but it inevitably will bring a raft of new security flaws and vulnerabilities as well. Due to the widespread integration of software in tangible products and physical world processes, these flaws pose risks that are qualitatively different from the risks associated with traditional security defects confined to the digital environment. The emergence of the Internet of Things is one example of the spreading risk. In this rapidly evolving environment, active security research and testing are crucial

Comments on expanding civic participation in voting by expanded use of the Internet

Hoke\u27s comments to the FCC on expanding civic participation in voting by expanded use of the Internet. Hoke recommends that the FCC not become involved in election regulatory issues concerning the Internet, but will support a different federal regulatory agency with national security and technical-cybersecurity expertise receiving primary jurisdiction over election cybersecurity