Star formation and accretion in the circumnuclear disks of active galaxies

We explore the evolution of supermassive black holes (SMBH) centered in a circumnuclear disk (CND) as a function of the mass supply from the host galaxy and considering different star formation laws, which may give rise to a self-regulation via the injection of supernova-driven turbulence. A system of equations describing star formation, black hole accretion and angular momentum transport was solved for an axisymmetric disk in which the gravitational potential includes contributions from the black hole, the disk and the hosting galaxy. Our model extends the framework provided by Kawakatu et al. (2008) by separately considering the inner and outer part of the disk, and by introducing a potentially non-linear dependence of the star formation rate on the gas surface density and the turbulent velocity. The star formation recipes are calibrated using observational data for NGC 1097, while the accretion model is based on turbulent viscosity as a source of angular momentum transport in a thin viscous accretion disk. We find that current data provide no strong constraint on the star formation recipe, and can in particular not distinguish between models entirely regulated by the surface density, and models including a dependence on the turbulent velocity. The evolution of the black hole mass, on the other hand, strongly depends on the applied star formation law, as well as the mass supply from the host galaxy. We suggest to explore the star formation process in local AGN with high-resolution ALMA observations to break the degeneracy between different star formation models.Comment: 13 pages, 15 figures, 6 tables, accepted at A&

Some implications of sampling choices on comparisons between satellite and model aerosol optical depth fields

The comparison of satellite and model aerosol optical depth (AOD) fields provides useful information on the strengths and weaknesses of both. However, the sampling of satellite and models is very different and some subjective decisions about data selection and aggregation must be made in order to perform such comparisons. This work examines some implications of these decisions, using GlobAerosol AOD retrievals at 550 nm from Advanced Along-Track Scanning Radiometer (AATSR) measurements, and aerosol fields from the GEOS-Chem chemistry transport model. It is recommended to sample the model only where the satellite flies over on a particular day; neglecting this can cause regional differences in model AOD of up to 0.1 on monthly and annual timescales. The comparison is observed to depend strongly upon thresholds for sparsity of satellite retrievals in the model grid cells. Requiring at least 25% coverage of the model grid cell by satellite data decreases the observed difference between the two by approximately half over land. The impact over ocean is smaller. In both model and satellite datasets, there is an anticorrelation between the proportion <i>p</i> of a model grid cell covered by satellite retrievals and the AOD. This is attributed to small <i>p</i> typically occuring due to high cloud cover and lower AODs being found in large clear-sky regions. Daily median AATSR AODs were found to be closer to GEOS-Chem AODs than daily means (with the root mean squared difference being approximately 0.05 smaller). This is due to the decreased sensitivity of medians to outliers such as cloud-contaminated retrievals, or aerosol point sources not included in the model

Taxation—Tax Benefit Rule Applicable to Section 357 Liquidations

Commissioner v. Anders, 414 F.2d 1283 (10th Cir. 1969)

Empowering effective fathering through an informational-relational model of local church men\u27s ministry

https://place.asburyseminary.edu/ecommonsatsdissertations/1427/thumbnail.jp

Taxation—Tax Benefit Rule Applicable to Section 357 Liquidations

Commissioner v. Anders, 414 F.2d 1283 (10th Cir. 1969)

EFFECTS OF PROXIMAL STABILITY TRAINING ON SPORT PERFORMANCE AND PROXIMAL STABILITY MEASURES

Proximal stability, or the ability to stabilize and actively control the spine, pelvis and trunk, has been reported to influence sport performance. Traditional training practices for the proximal segments have had little success improving sport performance. The purpose of this dissertation was to investigate the effects a sport specific proximal stability training program can have on throwing velocity and measures of muscular endurance and power which target the proximal segments of the pelvis, spine and trunk. A stratified randomized clinical trial was implemented with a pre- to post-intervention design. Forty-six healthy, Division III collegiate female softball (n=17) and male baseball (n=29) players were randomly assigned to one of two training groups for 7 weeks; a traditional endurance training group (ET) (n=21) or a power stability training group (PS) (n=25). The primary outcome measures were the change in peak throwing velocity/Kg of body weight in mph. Mean throwing velocity, power outputs from a one-repetition maximum chop test and lift test (watts/Kg body weight), and muscular endurance plank tests. Student’s independent t-tests were used to compare differences between change scores of all dependent variables. Peak throwing velocity change scores were significantly faster (ET= .21 ±.55 mph, PS= 3.4 ±1.1 mph, p\u3c .001) in the PS at post-intervention when compared to the ET group. Change scores were significantly greater in the PS group for mean throwing velocity, (ET= 1.1 ±1.6 mph vs. PS= 3.7 ±1.8 mph, p\u3c .001), chop (watts), (ET= 20 ±78 watts vs. PS= 105 ±68 watts, p\u3c .001), and lift, (ET= 49 ±62 watts vs. PS= 114 ±73 watts, p= .003). There were no change score differences for the side and prone plank endurance measures in seconds (p≥ .60). The PS group increased primary outcome measures over the ET program, indicating a more sport specific training regimen targeting the proximal segments is beneficial to both the power measures and throwing performance

Mechanical Recycling of Automotive Composites for Use as Reinforcement in Thermoset Composites

The aim of this research was to investigate the potential use of recycled glass fibre composite materials as a replacement for virgin reinforcing materials in new thermoset composites. Specifically the closed-loop mechanical recycling of composites used heavily in the automotive sector known as dough and sheet moulding composites, DMC and SMC respectively, are investigated. The recycling of glass reinforced thermoset polymer composite materials has been an area of investigation for many years and composites used in the automotive industry are of particular interest due to legislative and social pressures on the industry. The mechanical recycling process and then collection of useful fibrous grades of recycled materials, recyclate, by a novel air separation technique were investigated first. The properties of these recyclate fibres were characterised and compared directly with the properties of virgin glass fibres they were to be used to replace. Single fibre tensile tests were employed to compare the strengths of the fibres and single fibre pull-out tests were used to investigate the strength of the interface between the fibres and a polyester matrix. These tests showed the recyclate fibres to be weaker and have a poorer interface with the polyester matrix than the virgin glass fibres. Understanding the properties of the recyclate materials meant their reformulation into new composites could be carefully considered for the production of new high performance materials. Two grades of the collected recyclate materials were then reformulated in to new DMC and SMC composites, replacing percentages of the virgin glass fibre reinforcement. The mechanical properties of the resulting manufactured composites were characterised throughout for direct comparison against one another and an unmodified control material, using both three-point flexural tests and Charpy impact tests. Through the modification of existing manufacturing techniques and the development of novel production equipment it has been possible to successfully manufacture both DMC and SMC composites with the recyclate materials used to replace virgin glass fibres. Virgin glass fibres have successfully been replaced by recyclate materials without disrupting standard production techniques and with minimal reduction of the mechanical properties of the resulting composites. As the loadings of recyclate materials used were greatly increased both the flexural and impact strengths were significantly degraded and it was found that chemical modification of the composite could be used to improve these formulations. It has been shown that the recyclate materials should be considered and treated as a distinct reinforcing ingredient, separately from the remaining virgin glass fibres