The reactions of acid halides with sodium, magnesium, zinc and amalgams

The reactions of acid halides with metals are of interest because there seems to be a possibility of abstracting the halogens from two molecules of the halide, and thereby bringing about a coupling reaction; or the formation of an intermediate organo-metallic compound which would react with another molecule of the acid halide. The result of these reactions should be the formation of diacetyl and acetyl chloride and of dibenzoyl or benzil from benzoyl chloride. This procedure would be far better than the usual procedures for the preparation of these compounds...The results reported in the literature by different workers, on the reaction of benzoyl chloride with metals, do not agree and very little work has been reported on the reaction of acetyl halides with metals. These facts suggested an investigation of this subject --Introduction, page 1-2

Globular Cluster Scale Sizes in Giant Galaxies: Orbital Anisotropy and Tidally Under-filling Clusters in M87, NGC 1399, and NGC 5128

We investigate the shallow increase in globular cluster half-light radii with projected galactocentric distance $R_{gc}$ observed in the giant galaxies M87, NGC 1399, and NGC 5128. To model the trend in each galaxy, we explore the effects of orbital anisotropy and tidally under-filling clusters. While a strong degeneracy exists between the two parameters, we use kinematic studies to help constrain the distance $R_\beta$ beyond which cluster orbits become anisotropic, as well as the distance $R_{f\alpha}$ beyond which clusters are tidally under-filling. For M87 we find $R_\beta > 27$ kpc and $20 < R_{f\alpha} 13$ kpc and $10 < R_{f\alpha} < 30$ kpc. The connection of $R_{f\alpha}$ with each galaxy's mass profile indicates the relationship between size and $R_{gc}$ may be imposed at formation, with only inner clusters being tidally affected. The best fitted models suggest the dynamical histories of brightest cluster galaxies yield similar present-day distributions of cluster properties. For NGC 5128, the central giant in a small galaxy group, we find $R_\beta > 5$ kpc and $R_{f\alpha} > 30$ kpc. While we cannot rule out a dependence on $R_{gc}$, NGC 5128 is well fitted by a tidally filling cluster population with an isotropic distribution of orbits, suggesting it may have formed via an initial fast accretion phase. Perturbations from the surrounding environment may also affect a galaxy's orbital anisotropy profile, as outer clusters in M87 and NGC 1399 have primarily radial orbits while outer NGC 5128 clusters remain isotropic.Comment: 16 pages, 7 figures, 4 tables, Accepted for publication in MNRA

Additively Manufactured RCS for Small Satellites and Landers

After a fifty year absence, NASA’s return to the lunar surface under the Artemis Program – for long term human exploration and utilization – is driving commercial and academic opportunities for small satellite and small lander platforms (e.g., Commercial Lunar Payload Services program – CLPS). Bipropellant thrusters are a reliable, low risk, and flight proven method for the propulsion and attitude control that is required for complex maneuvers such entry, descent, and landing (EDL) or in-space proximity operations. However, due to the increasingly competitive commercial spaceflight market in the last decade, satellite subsystems must also be affordable to buy their way into the final mission design and engineering solution. Therefore starting in 2019, and based off prior satellite integration work, Aerojet Rocketdyne (AR) undertook an advanced propulsion development effort to combine modern metal additive manufacturing (AM) techniques with thrust scalable hypergolic MON-25 propulsion technology to create a high performance and fully integrated (i.e., multiple thrusters integrated into a single package) reaction control system (RCS) at a fraction of the production cost when compared to the heritage designs that are assembled from individual thrusters. The point-of-departure for the RCS design comes from a new line of additively manufactured thrusters that stably burn volatile MON-25 oxidizer with monomethylhydrazine (MMH) fuel at thrust levels of 5 lbf and 100 lbf. Cost at the subsystem level is lowered by the AM integration of parts and functions which reduces the build of materials, touch labor, and assembly time. In addition, AM allows the design to be adaptable to changing requirements such as the number of thrusters, orientation, and thrust level. Cost at the satellite level is reduced by leveraging MON-25’s lower freezing point of -55 °C (compared to traditional dinitrogen tetroxide oxidizer) to minimize mass, thermal, and power requirements while operating in deep-space environments. In addition, thruster operation at the equal volume mixture ratio for MMH/MON-25 allows for a modular approach to tank design and a predictable center of gravity during maneuvering. This paper provides an overview of the ISE-5 and the ISE-100 MON-25 thruster technology that powers the integrated designs as well as the development progress of the AM RCS concept itself. This includes reduction to practice activities such as proof-of-concept AM material test demonstrators and water flow test units

Spatial Drift Dynamics of Shovelnose Sturgeon and Pallid Sturgeon Prelarvae in the Transition Zone of Ft. Peck Reservoir

Habitats in reservoir headwaters may cause high mortality of sturgeon prelarvae. Short inter-reservoir reaches export drifting prelarvae from hatch locations into reservoirs. However, flooded vegetation could entrain prelarvae. We used 2 day post hatch (dph) shovelnose sturgeon (Scaphirhynchus platorynchus) and 1-dph pallid sturgeon (Scaphirhynchus albus) to determine the spatial dynamics of drifting prelarvae.We released 220,000 2-dph shovelnose sturgeon 4 km upstream of Ft. Peck Reservoir and 135,000 1-dph pallid sturgeon 2.5 km upstream of the reservoir the following day. We recaptured shovelnose sturgeon prelarvae with nets deployed along three transects of the transition zone and within the headwaters of the reservoir.We sampled 5148.2 m3 of water and recaptured 323 prelarval shovelnose sturgeon for a recapture rate of 0.14 percent. Fifty-nine percent of recaptured prelarvae were recaptured from the thalweg, 12 percent from the flooded vegetation-main channel interface, 9 percent from the channel border, and 19 percent from the zero-velocity area of Ft. Peck Reservoir. We recaptured pallid sturgeon prelarvae with nets deployed along one transect of the transition zone and within the headwaters of the reservoir. We sampled 6608.5 m3 of water and recaptured 397 pallid sturgeon prelarvae for a recapture rate of 0.29 percent. Twenty one percent of prelarvae were recaptured within the thalweg, 0.25 percent were recaptured along the channel margins, and 79 percent from the zero-velocity area of Ft. Peck Reservoir. Although recapture rates were low, the majority of prelarvae were captured in the thalweg and transported to the headwaters of Ft. Peck Reservoir. The drift dynamics observed in this study provide a springboard for further research