All Faculty Deposits
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The "All Faculty Deposits" collection contains works deposited by faculty and appointed delegates from the Elements (EFARs) system. For help with Elements, see Frequently Asked Questions on the Provost's website. In general, items can only be deposited if the item is a scholarly article that is covered by Virginia Tech's open access policy, or the item is openly licensed or in the public domain, or the item is permitted to be posted online under the journal/publisher policy, or the depositor owns the copyright. See Right to Deposit on the VTechWorks Help page. If you have questions email us at vtechworks@vt.edu.
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- Resolving Land Use ConflictsTideman, Nicolaus (Farm Foundation, 1972)
- The alleged existence of partially oxidized Mg[Pt(CN)4]Cl0.28.7H2O and the attempted preparation of the analogous beryllium(2+) and barium(2+) derivatives. A caveatKoch, Timothy R.; Gebert, E.; Williams, Jack M. (American Chemical Society, 1976-06)
- Postemergence growth of the ovarian follicles of Aedes aegyptiHagedorn, H. H.; Turner, Sarah; Hagedorn, E. A.; Pontecorvo, David; Greenbaum, Paula; Wheelock, Geofrey; Flanagan, T. R. (1977)Growth of the ultimate follicle to the resting stage in Aedes aegypti is linear and reaches maximum development about 6Ohr after emergence. Decapitations and ligations at various times after emergence indicate that growth of the follicles is under the control of factors from the head and thorax. Release of head factor occurs within one day after emergence and is relatively sudden. The thoracic factor is released gradually over a 2 to 3 day period. Near normal growth of follicles in isolated abdomens after topical application of juvenile hormone (JH) indicates that the thoracic factor is JH from the corpora allata and demonstrates the feasibility of using this system as a JH assay. When ecdysone was injected simultaneously with JH the follicles failed to grow.
- X-ray diffuse scattering of one-dimensional tetracyanoplatinate saltsSchultz, A. J.; Stucky, G. D.; Williams, Jack M.; Koch, Timothy R.; Maffly, R. L. (Elsevier, 1977-01)
- Structural studies of precursor and partially oxidized conducting complexes. II. A neutron diffraction study of disodium dibromotetracyanoplatinate dihydrateMaffly, Robert L.; Johnson, Paul L.; Koch, Timothy R.; Williams, Jack M. (International Union of Crystallography, 1977-02-01)
- Structural studies of precursor and partially oxidized conducting complexes. VI. A neutron diffraction study of dicesium tetracyanoplatinate(II) monohydrateJohnson, Paul L.; Koch, Timothy R.; Williams, Jack M. (International Union of Crystallography, 1977-04-15)
- Structural studies of precursor and partially oxidized conducting complexes. VII. A neutron diffraction study of disodium tetracyanoplatinate(II) trihydrateJohnson, Paul L.; Koch, Timothy R.; Williams, Jack M. (International Union of Crystallography, 1977-06-01)
- Structural studies of precursor and partially oxidized conducting complexes. XI. A neutron diffraction study of barium dibromotetracyanoplatinate(IV) hydrateKoch, Timothy R.; Johnson, Paul L.; Washecheck, Donald M.; Cornish, Thomas L.; Williams, Jack M. (International Union of Crystallography, 1977-10-01)
- Cucumber pollen germination and tube elongation inhibited or reduced by pesticides and adjuvantsGentile, A. G.; Vaughan, A. W.; Pfeiffer, Douglas G. (1978)
- Coleoptera of poultry manure in caged-layer houses in North CarolinaPfeiffer, Douglas G. (1980)
- Effect of tree fertilization on numbers and development of pear psylla (Homoptera: Psyllidae), and on fruit damagePfeiffer, Douglas G.; Burts, E. C. (1983)
- Effect of tree fertilization on protein and free amino acid content and feeding rate of pear psylla (Homoptera: Psyllidae)Pfeiffer, Douglas G.; Burts, E. C. (1984)
- Liquidity as a Latent Variable - an Application of the Mimic ModelSpanos, Aris (Blackwell, 1984-01-01)
- Effects of field applications of paraquat on densities of Panonychus ulmi (Koch) and Neoseiulus fallacis (Garman)Pfeiffer, Douglas G. (1986)Neoseiulus fallacis (Garman) is the most important acarine predator of the European red mite, Panonychus ulmi (Koch), in sprayed apple orchards in the eastern United States [Poe, S. L., and W. R. Enns. 1969. Predaceous mites (Acarina: Phytoseiidae) associated with Missouri orchards. Trans. Missouri Acad. Sci. 3: 69-82; Berkett, L. P., and H. Y. Forsythe. 1980. Predaceous mites (Acari) associated with apple foliage in Maine. Can. Entomol. 112: 497-502]. Populations of this predator are often present only at very low densities in Virginia orchards, however. The herbicide paraquat has been shown to be toxic to N. fallacis using slide-dip bioassays [Rock, G. C., and D. R. Yeargan. 1973. Toxicity of apple orchard herbicides and growth-regulating chcmicnls to Neoseiulus fallacis and twospotted spider mite. J. Econ. Entomol. 66: 1342-1343; Hislop, R. G., and R. J. Prokopy. 1981 . Integrated management of phytophagous mites in Massachusetts (U.S.A.) apple orchards. 2. Influence of pesticides on the predator Amblyseius fallacis (Acarina: Phytoseiidae) under laboratory field conditions. Protect. Ecol. 3: 157-1721. Paraquat is commonly applied in Virginia apple orchards in early spring while N. fallacis is still in its overwintering site in the orchard ground cover. The purpose of this study was to determine if field applications of paraquat affect densities of P. ulmi and its predator, N. fallacis, in the tree canopy. Slide-dip bioassay data, while very useful for comparing toxicity from topical applications of pesticides, are highly artificial and do not reflect other factors in mortality (contact with dried residues, behavioral responses, habitat modification). Other methods should be employed to complement slide-dip data (Dennehey, T. J., J. Granett, and T. F. Leigh. 1983. Relevance of slide-dip and residual bioassay comparisons to detection of resistance in spider mites. J. Econ. Entomol. 76: 1225-1230).
- Relative susceptibility to slide-dip application of cyhexatin in three populations of Panonychus ulmi (Koch) in Virginia apple orchardsPfeiffer, Douglas G.; Pfeiffer, S. W. (1986)
- Nitrogen and potassium fertilization effects on yield and quality of burley tobaccoEvanylo, Gregory K.; Sims, J. L. (1987)Field studies were conducted in 1983 and 1984 at Lexington, KY to examine the effects of N and K fertilizer on yield and chemical quality of burley tobacco (Nicotiana tabacum L. cv. Ky 14). Treatments included: NH4NO3 at rates of 112, 280, and 448 kg N ha-1; and two sources (K2SO4 and KC1), each at rates of 0, 112, 224, and 448 kg K ha-1. The following agronomic and chemical characteristics were examined: yield, price, leaf N, P, K, Ca, Mg, Cl, Mo, total alkaloid, and solanesol concentrations. Cured leaf yield, price, and solanesol concentration were strongly influenced by N X K interactions. Each was raised by increasing N rates when no K was applied; however, at higher K levels, increasing N rates resulted in smaller price increases, no yield changes, and reductions in solanesol concentrations. Reductions in cured leaf Mo concentration relative to N, K, and Mg levels with increasing K fertilization beyond 0 kg ha-1 were exaggerated as N rates were raised. No effect of N rates on total alkaloids or solanesol concentrations were noted while increased K rates increased concentrations of both. Greater cured leaf yields and Mo concentrations were achieved with KC1 than with K2SO4. The positive effect of KC1 on Mo concentration at low N application rates was reduced by increased N fertilization suggesting that Mo uptake was enhanced by Cl_ but reversed at high levels of NO_3 application.
- Disruption of olfactory communication in oriental fruit moth and lesser appleworm in a Virginia peach orchardPfeiffer, Douglas G.; Killian, J. C. (1988)
- Optimum Current Control for a High Speed Axial Gap Permanent Magnet Synchronous MotorLai, J. S.; Bailey, J. M.; Young, R. W.; Sohns, C. W.; Hawsey, R. A. (IEEE, 1989-01-01)A high-speed (20,000 r/min) axial-gap permanent magnet (PM) synchronous motor constructed and controlled using a novel algorithm is described. An optimization algorithm using the Newton-Raphson method is proposed to solve the maximum torque/amp problem for salient-type PM motors. The optimum voltage and torque angle for different speeds are further derived from optimum dq-axes currents so that decoupled control can be applied to a six-step inverter. The complete drive system can be implemented using open-loop optimum voltage and torque angle trajectories or closed-loop control with one variable controlled by a lookup table and the other variable controlled by a closed-loop controller. The open-loop and closed-loop control systems are simulated. Although torque pulsation cannot be avoided with a six-step inverter, acceleration is quite smooth due to high load inertia.
- Impact of Automation on the Reliability of the Athens Utilities Board's Distribution SystemLawler, J. S.; Lai, J. S.; Monteen, L. D.; Patton, J. B.; Rizy, D. T. (IEEE, 1989-01-01)In this paper we discuss the reliability effects of distribution automation on the Athens Utilities Board (AUB) in Athens, Tennessee. This investigation is part of the Athens Automation and Control Experiment sponsored by the U. S. Department of Energy, Office of Energy Storage and Distribution, Electric Energy Systems Program. In this experiment, distribution feeder equipment on twelve feeders connected to three substations is being remotely controlled from a central dispatch center, A supervisory control and data acquisition system provides substation and feeder monitoring and remote control of feeder circuit breakers, power reclosers, and load break switches. An analytical study is presented to show the improvement in conventional distribution system reliability indices that are achieved at AUB as a function of the penetration of automation equipment. The value of automation predicted by the study is highly sensitive to the historical outage data used in the analysis and to the economic worth of reliability assigned by the utility. These sensitivities are well known and account, at least in part, for the reluctance of some upper utility managers to invest in automation systems. Operating experience with the AUB automation system has shown that there are significant intangible reliability benefits and tangible cost savings associated with automation that are outside the scope of conventional distribution reliability indices. Eight case studies are described, from actual AUB operations, where the automation system resulted in significant cost savings and reliability benefits that are not captured by conventional reliability indices, Other utilities should expect similar benefits, which will be difficult to quantify analytically but, which add to the value of and justification for distribution automation. © 1989 IEEE