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Search Results: 1 - 10 of 179173 matches for " Peter H. "
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Tensors of Rank Two in Tensor Flight Dynamics  [PDF]
Peter H. Zipfel
Advances in Aerospace Science and Technology (AAST) , 2018, DOI: 10.4236/aast.2018.32002
Abstract:
Tensor flight dynamics solves flight dynamics problems using Cartesian tensors, which are invariant under coordinate transformations, rather than Gibbs’ vectors, which change under time-varying transformations. Three tensors of rank two play a prominent role and are the subject of this paper: moment of inertia, rotation, and angular velocity tensor. A new theorem is proven governing the shift of reference frames, which is used to derive the angular velocity tensor from the rotation tensor. As applications, the general strap-down INS equations are derived, and the effect of the time-rate-of-change of the moment of inertia tensor on missile dynamics is investigated.
Asymmetries of solar coronal extreme ultraviolet emission lines
H. Peter
Physics , 2010, DOI: 10.1051/0004-6361/201014433
Abstract: The profiles of emission lines formed in the corona contain information on the dynamics and the heating of the hot plasma. Only recently has data with sufficiently high spectral resolution become available for investigating the details of the profiles of emission lines formed well above 10^6 K. These show enhanced emission in the line wings, which has not been understood yet. Line profiles of Fe XV formed at 2.5 MK acquired by the Extreme ultraviolet Imaging Spectrometer (EIS) onboard the Hinode solar space observatory are studied using multi Gaussian fits, with emphasis on the resulting line widths and Doppler shifts. In the major part of the active region, the spectra are best fit by a narrow line core and a broad minor component. The latter contributes some 10% to 20% to the total emission, is about a factor of 2 broader than the core, and shows strong blueshifts of up to 50 km/s. On average, the line width increases from the footpoints to the loop top for both components. A component with high upflow speeds can be found also in small restricted areas. The coronal structures consist of at least two classes that are not resolved spatially but only spectroscopically and that are associated with the line core and the minor component. Because of their huge line width and strong upflows, it is proposed that the major part of the heating and the mass supply to the corona is actually located in source regions of the minor component. The siphon flows and draining loops seen in the line core component are consistent with structures found in a 3D MHD coronal model. Despite the quite different appearance of the large active region corona and small network elements seen in transition region lines, both show similar line profile characteristics. This indicates that the same processes govern the heating and dynamics of the transition region and the corona.
Magnetic field diagnostics and spatio-temporal variability of the solar transition region
H. Peter
Physics , 2013, DOI: 10.1007/s11207-013-0270-3
Abstract: Magnetic field diagnostics of the transition region from the chromosphere to the corona faces us with the problem that one has to apply extreme UV spectro-polarimetry. While for coronal diagnostic techniques already exist through infrared coronagraphy above the limb and radio observations on the disk, for the transition region one has to investigate extreme UV observations. However, so far the success of such observations has been limited, but there are various projects to get spectro-polarimetric data in the extreme UV in the near future. Therefore it is timely to study the polarimetric signals we can expect for such observations through realistic forward modeling. We employ a 3D MHD forward model of the solar corona and synthesize the Stokes I and Stokes V profiles of C IV 1548 A. A signal well above 0.001 in Stokes V can be expected, even when integrating for several minutes in order to reach the required signal-to-noise ratio, despite the fact that the intensity in the model is rapidly changing (just as in observations). Often this variability of the intensity is used as an argument against transition region magnetic diagnostics which requires exposure times of minutes. However, the magnetic field is evolving much slower than the intensity, and thus when integrating in time the degree of (circular) polarization remains rather constant. Our study shows the feasibility to measure the transition region magnetic field, if a polarimetric accuracy on the order of 0.001 can be reached, which we can expect from planned instrumentation.
Sensitivity of durum wheat (Triticum turgidum) to various postemergence herbicides  [PDF]
Nader Soltani, Christy Shropshire, Peter H. Sikkema
Agricultural Sciences (AS) , 2011, DOI: 10.4236/as.2011.24058
Abstract: There are a limited number of herbicide options available for durum wheat production in Ontario, Canada. Four field studies were conducted in Ontario, Canada over a three year period (2008, 2009 and 2010) to evaluate the sensitivity of spring planted durum wheat to post-emergence (POST) applications of dichlorprop/2,4-D, dicamba/ MCPA/mecoprop, clopyralid, bromoxynil/MCPA, pyrasulfotole/bromoxynil, thifensulfuron/tribenuron + MCPA amine, fluroxypyr + MCPA ester, tralkoxydim and fenoxaprop-p-ethyl/safener at the manufacturers’ recommended dose and twice that dose. Visible injury in durum wheat were 0 to 2.4% with dichlorprop/2,4-D, 0 to 6% with dicamba/MCPA/mecoprop, 0 to 0.4% injury with clopyralid, 0 to 1.4% injury with bromoxynil/MCPA, 0 to 3.5% with pyrasulfotole/bromoxynil, 0 to 5% with thifensulfuron/tribenuron + MCPA amine, 0 to 2.6% with fluroxypyr + MCPA ester, 0 to 5% with tralkoxydim and 0.4% to 8% with fenoxaprop-pethyl/safener at various evaluation dates (1, 2, 3 and 4 weeks after treatment). Durum wheat height was decreased as much as 5% with dicamba/ MCPA/mecoprop, 4% with pyrasulfotole/bromoxynil and 6% with fenoxaprop-pethyl/safener but was not affected with other herbicides evaluated. There was no decrease in durum wheat yield with the herbicides evaluated.
Urea Ammonium Nitrate as the Carrier for Herbicides in Winter Wheat  [PDF]
Nader Soltani, Christy Shropshire, Peter H. Sikkema
American Journal of Plant Sciences (AJPS) , 2012, DOI: 10.4236/ajps.2012.33050
Abstract: Urea ammonium nitrogen can be used as a carrier for herbicides to provide growers with an option for the control of broadleaf weeds and spraying nitrogen fertilizer in one pass in winter wheat. Field studies (six in total) were seeded in the autumn of 2005, 2006 and 2007 at Exeter and Ridgetown, Ontario, Canada to determine if UAN can be used as a carrier for bromoxynil/MCPA, dichlorprop/2,4-D, dicamba/MCPA/mecoprop, or thifensulfuron/tribenuron applied postemergence (POST) at three application timings (approximately April 20, May 1 and May 10) in winter wheat. Winter wheat injury was as much as 4%, 5%, 4% and 5% for bromoxynil/MCPA, dichloroprop/2,4-D, dicamba/MCPA/ mecoprop or thifensulfuron/tribenuron, respectively. There was minimal visible winter wheat injury with treatments evaluated at 4 and 9 week after treatment. There was no significant reduction in winter wheat height or yield with herbicides evaluated at various application timings except for dicamba/MCPA/mecoprop treatment which reduced height 3% and yield 25% at May 10 compared with April 20 application timing. Herbicides carrier had no effect on winter wheat height or yield with evaluated herbicides. Based on this research there is potential for co-application of UAN and bromoxynil/MCPA, dichlorprop/2,4-D, dicamba/MCPA/mecoprop, or thifensulfuron/tribenuron applied (POST) early in the spring in winter wheat.
Safening effect of bentazon on cloransulam-methyl and halosulfuron-methyl in dry bean  [PDF]
Nader Soltani, Christy Shropshire, Peter H. Sikkema
Agricultural Sciences (AS) , 2012, DOI: 10.4236/as.2012.33043
Abstract: Bentazon, applied as a tankmix, has been shown to have the potential for reducing the injury from some POST herbicides. Field experiments were conducted in 2008 and 2009 at Exeter, ON and in 2009 at Ridgetown, ON to determine if the addition of bentazon reduces the injury from cloransulam-methyl or halosulfuron-methyl applied POST in black, cranberry, kidney and white beans. Bentazon added to cloransulam-methyl reduced the level of injury 0 to 6% at 17.5 g·ai·ha–1 and 0 to 9% at 35 g·ai·ha–1 in dry bean. Bentazon added to halosulfuron-methyl reduced the level of injury as much as 4% at 35 g·ai·ha–1 and 6% at the 70 g·ai·ha–1. Bentazon added to cloransulam-methyl increased plant height as much as 3 cm. The addition of bentazon to halosulfuron-methyl had no effect on the height of various market classes of dry bean. Bentazon added to cloran-sulam-methyl generally has no effect on seed moisture content in black and white bean but decreased seed moisture content of cranberry and kidney bean as much as 4%. The addition of bentazon to halosulfuron-methyl caused no effect on seed moisture content of dry bean. Cloransulam-methyl caused a 7% to 18% reduction in dry bean yield compared to halosulfuron-methyl and 12% to 21% reduction in yield compared to bentazon. Bentazon added to cloransulam-methyl increased dry bean yield by 0.16 and 0.31 t·ha–1 at Exeter (2009) and Ridgetown (2009) respectively. The addition of bentazon to halosulfuron-methyl had no effect on dry bean yield.
Tolerance of mung bean to postemergence herbicides  [PDF]
Nader Soltani, Christy Shropshire, Peter H. Sikkema
Agricultural Sciences (AS) , 2013, DOI: 10.4236/as.2013.410075
Abstract:

There are a limited number of postemergence (POST) herbicides available for weed management in mung bean production in Ontario. Five field studies were conducted in 2010, 2011 and 2012 near Exeter, Ontario and in 2011 and 2012 near Ridgetown, Ontario to determine the tolerance of mung bean to fomesafen, bentazon, bentazon + fomesafen and halosulfuron applied POST at the 1X and 2X proposed manufacturer’s recommended rate. Bentazon caused 5%-29%, 4%-31%, and 2%-18% injury, fomesafen caused 3%-17%, 1%-7%, and 0%-6% injury, bentazon + fomesafen caused 6%-40%, 4%-37%, and 1%-20% injury, and halosulfuron caused 13%-65%, 8%-75%, and 5%-47% injury in mung bean at 1, 2, and 4 weeks after treatment (WAT), respectively. At Exeter, fomesafen had no adverse effect on height of mung bean but bentazon, bentazon + fomesafen and halosulfuron decreased mung bean height as much as 5% compared to the untreated control. At Ridgetown, there was no decrease in mung bean height due to the herbicides applied. Fomesafen had no adverse effect on shoot dry weight of mung bean but bentazon, bentazon + fomesafen and halosulfuron decreased shoot dry weight of mung beans as much as 43%, 47%, and 57%, respectively. Fomesafen, bentazon, bentazon + fomesafen and halosulfuron had no adverse effect on the seed moisture content and seed yield of mung bean with the exception of halosulfuron applied POST at 70 g ai ha-1 which increased seed moisture content 0.4% at Exeter and 1.4% at Ridgetown and decreased yield 16% at Exeter compared to the untreated control. Based on these results, there is not an adequate margin of crop safety for bentazon, bentazon + fomesafen and halosulfuron applied POST in mung bean. However, there is potential for fomesafen applied POST at the proposed manufacturer’s rate of 240 g ai ha-

Volunteer Glyphosate and Glufosinate Resistant Corn Competitiveness and Control in Glyphosate and Glufosinate Resistant Corn  [PDF]
Nader Soltani, Christy Shropshire, Peter H. Sikkema
Agricultural Sciences (AS) , 2014, DOI: 10.4236/as.2014.55042
Abstract:

Glyphosate and glufosinate resistant (RR/LL) volunteer corn has become a problem when hybrid RR/LL corn follows hybrid RR/LL corn in the rotation. A total of six field trials were conducted over a three-year period (2008 to 2010) in southwestern Ontario to 1) evaluate the competitiveness of volunteer RR/LL corn in hybrid RR/LL corn, and 2) determine how to control volunteer RR/LL corn in hybrid RR/LL corn. The predicted volunteer RR/LL corn density to reduce hybrid RR/LL corn yield by 5% was 1.7 volunteer RR/LL corn plants m-2. There was no crop injury in hybrid RR/LL corn with herbicides evaluated at 1 and 2 WAA except for rimsulfuron(15 g·ai·ha-1) and foramsulfuron (35 g·ai·ha-1) which caused as much as 5% and 11% injury in hybrid RR/LL corn, respectively. Glyphosate (1800 g·ae·ha-1), glufosinate(500 g·ae·ha-1) and glyphosate + glufosinate (1800 + 500 g·ae·ha-1) provided up to 18%, 10% and 21% control of volunteer RR/LL corn, respectively. The POST application of rimsulfuron (15 g·ai·ha-1), nicosulfuron (25 g·ai

Battery Modeling: A Versatile Tool to Design Advanced Battery Management Systems  [PDF]
Peter H. L. Notten, Dmitri L. Danilov
Advances in Chemical Engineering and Science (ACES) , 2014, DOI: 10.4236/aces.2014.41009
Abstract:

Fundamental physical and (electro) chemical principles of rechargeable battery operation form the basis of the electronic network models developed for Nickel-based aqueous battery systems, including Nickel Metal Hydride (NiMH), and non-aqueous battery systems, such as the well-known Li-ion. Refined equivalent network circuits for both systems represent the main contribution of this paper. These electronic network models describe the behavior of batteries during normal operation and during over (dis) charging in the case of the aqueous battery systems. This makes it possible to visualize the various reaction pathways, including convention and pulse (dis) charge behavior and for example, the self-discharge performance.

Response of cranberry and kidney beans to linuron  [PDF]
Nader Soltani, Christy Shropshire, Peter H. Sikkema
Agricultural Sciences (AS) , 2013, DOI: 10.4236/as.2013.412087
Abstract:

Field studies were conducted in 2009 and 2010 at the Huron Research Station, Exeter, Ontario and the University of Guelph Ridgetown Campus, Ridgetown, Ontario to determine the tolerance of four cultivars of cranberry bean (“Etna”, “Hooter”, “SVM Taylor”, and “Capri”) and four cultivars of kidney bean (“Red Hawk”, “Pink Panther”, “Calmont”, and “Majesty”) to linuron applied preemergence at 1125 and 2250 g·ai·ha-1. One week after emergence (WAE), linuron applied PRE caused 0.4% to 1.2% injury in “Etna”, “Hooter”, “SVM Tayler”, and “Capri” cranberry bean and 3.1% to 3.6% injury in “Red Hawk”, “Pink Panther”, “Calmont”, and “Majesty” kidney bean. At 2 and 4 WAE, there was no difference in injury among the dry bean cultivars. Contrast comparing injury due to linuron in cranberry vs kidney bean cultivars indicated 2.3%, 1.7%, and 1.2% greater injury in kidney bean compared to cranberry bean at 1, 2, and 4 WAE, respectively. Linuron PRE caused slightly greater injury in kidney bean compared to cranberry bean but crop injury was minimal with no adverse effect on plant height, shoot dry weight, seed moisture content, and yield under the environments evaluated. Based on this research,

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