The scattering by the perfectly electric conducting (PEC) half-plane and PEC zero thickness disk placed on parallel planes is considered. The fields are represented in the spectral domain, i.e. in the domain of Fourier transform. The operator equations with respect to the Fourier amplitudes of the scattered field are obtained. The kernel functions of these equations contain poles. After regularization procedure, which is connected with the elimination of the poles, operator equations are converted to the system of singular integral equations. The convergence of the solution is based on the corresponding theorems. The scattered field consists of the plane wave, reflected by the infinite part of the half-plane, cylindrical waves, which appear as a result of scattering by the edge of the half-plane, and spherical waves, which appear as a result of scattering by the disk and multiple re-scattering by the disk-half-plane. The total near-field distribution and far-field patterns of cylindrical waves are presented.

With the LAMOST DR4 and Gaia DR2 common red clump giant stars, we investigate the three-dimensional kinematics of Milky Way disk stars in mono-age populations between Galactocentric distances of R = 6 and 15 kpc. We confirm the 3D asymmetrical motions of recent works, and provide time tagging of the Galactic outer disk asymmetrical motions. Radial motions present a north-south asymmetry in the region corresponding to recent density and velocity substructures that were sensitive to the perturbations in the early 6 Gyr. What’s more, we discover a new velocity substructure in the north side corresponding to density dip found recently (“south-middle opposite”) in the radial and azimuthal velocity. Meanwhile, the vertical velocity with clear vertical bulk motions or bending mode motions has no clear asymmetry corresponding to the in-plane asymmetrical features.

The AAOmega Evolution of Galactic Structure (AEGIS) survey (P.I. Keller) was a moderate scale (45 nights) spectroscopic survey carried out with the AAOmega multi-fiber spectrograph at the Anglo-Australian Telescope. The input catalogue for the spectroscopic observations was derived from photometry of approximately 200 two-degree diameter fields obtained during the commissioning of the SkyMapper survey. The data consists of medium-resolution (R ~ 2,000) spectroscopy for approximately 70,000 thick disk and halo stars spanning a survey footprint of 4,900 square degrees. We plan to use the AEGIS data to further characterize the properties of the disk and halo systems and better constrain the assembly history of the Galaxy based on the behavior of the CEMP-no and CEMP-s stars in the sample.

We investigate here the effect of the selection function on the metallicity distribution function (MDF) as well as on the vertical metallicity gradient by studying similar lines-of-sight using four different spectroscopic surveys (APOGEE, LAMOST, RAVE and Gaia-ESO) which have different targeting strategies and therefore different selection functions. We create mock fields for each survey using two stellar population synthesis models, GALAXIA and TRILEGAL. The effects of the selection function are studied in detail by applying the selection function to the two models and comparing the MDF as well as vertical metallicity gradients of the selected sources with that of the underlying sample. We find a negligible selection function effect on the MDF as well as on the vertical metallicity gradients for APOGEE, RAVE and LAMOST, and estimate a mean vertical metallicity gradient of -0.241±0.028 dex kpc−1.

In order to find the most effective and economical method of incorporation, six preplant herbicides for cotton (Gossypium hirsutum L.) were incorporated with a tandem disk or field cultivator, or sprayed on unbedded soil prior to bedding with a disk bedder. These treatments were compared to incorporating sprayed beds with a rolling cultivator and no incorporation. A mixed population of pigweed (Amaranthus hybridus L. # AMACH and Amaranthus retroflexus L. # AMARE) was present each year. There was no significant difference in pigweed control among incorporation with a disk, field cultivator, or rolling cultivator. Puncturevine (Tribulus terrestris # TRBTE) and barnyardgrass [Echinochloa crus-galli (L.) Beauv. # ECHCG] were controlled best following rolling cultivator incorporation. Cotton lint yields were not affected by incorporation methods or herbicides. Economic analysis and weed control indicate that the field cultivator was the best way of incorporation.

Field studies were conducted in 1986-87 and 1988-89 to compare chiseling, disking, and skewtreading to no-till and to compare 0.3 and 0.4 kg ai ha−1 pronamide applied before or after fall tillages for weed control in fallow. Chiseling or disking in October 1986 when weeds were emerged reduced the dry weight of volunteer wheat about 90% the following spring; however, only disking reduced the dry weight of downy brome 90%. Disking or skewtreading in October 1988 before weeds germinated reduced the dry weight of volunteer wheat about 95% 6 mo later, but none of the three tillages reduced the dry weight of downy brome. Pronamide applied at 0.3 and 0.4 kg ha−1 to emerged downy brome and volunteer wheat with either chiseling or disking before or after herbicide application reduced the dry weight of both species 90% or more 6 mo later compared with tillage alone. If weeds did not emerge until early November, then only pronamide at 0.4 kg ha−1 applied in no-till or after fall tillage controlled both species at least 90%.

A field study was conducted to develop systems using cultural and chemical methods for control of bermudagrass (Cynodon dactylon L.) in cotton (Gossypium hirsutum L.). Several control options were promising. On areas prepared either with a moldboard plow or a disk, the sodium and magnesium salts of dalapon (2,2-dichloropropionic acid) at 4.7 kg/ha directed to 25-cm-high cotton and repeated at the 40-cm height or the ethyl ester of difenopenten {4-[4-[4-(trifluoromethyl)phenoxy] phenoxy]-2-pentenoic acid} directed to 15-cm-high cotton and repeated at the 30-cm height, with either standard or close cultivation as needed, provided good bermudagrass control. On areas prepared with a moldboard plow, the isopropyl amine salt of glyphosate [N-(phosphonomethyl)glycine] at 4.4 kg/ha over-the-top as a fall application with cultivation as needed was promising.

Field experiments were conducted to study the effects of various tillage and mulching practices on fruit maturity and weed suppression in pumpkins. Conventional tillage (CT), disking, no tillage with rye removed (RR), no tillage with standing rye (SR), and strip tillage (ST) were evaluated with and without ethalfluralin plus halosulfuron (1.5 plus 0.036 kg ai/ha, respectively) applied preemergence. In 2001, when heavy rain after herbicide application caused significant crop injury, the herbicides delayed maturity and significantly reduced yields of mature pumpkins within each herbicide treatment, total yields did not differ with tillage. In 2002, weed populations were significantly greater than those in 2001, and in 2002, regardless of herbicides, yields of mature fruit were greater in tillage treatments with higher rye residues (SR, ST). Although weed populations were less in one year than the other, herbicides provided effective control in both seasons, and RR, ST, and SR effectively suppressed weeds compared with CT. Averaged over treatments, greater yield losses were attributable to weed competition (42%) in 2002 than to herbicide injury (32%) in 2001.

This short review is intended to be a snapshot of some recent observational facts and open questions regarding the study of chemical evolution in the innermost regions of the Milky Way, as traced by spectroscopy of cool giant and supergiant stars.

We review our knowledge about the spiral structure of the disk of our Galaxy using tracers of star formation. These tracers reveal a 4-arm picture of the Galaxy.

A new method to extract information from color-magnitude diagrams (CMDs) is presented. We employ a Richardson-Lucy (RL) algorithm to the analysis of the observational uncertainties. The resulting reconstruction is a cleaned data set with which to perform analyses of the star formation history. For this task, synthetic stellar populations are built and compared with the data CMD. As an application, the star formation rate in the solar vicinity is recovered.

We minimize, with respect to shape, the moment of inertia of a turbine having the given lowest eigenfrequency of the torsional oscillations. The necessary conditions of optimality in conjunction with certain physical parameters admit a unique optimal design.