Synthesis of improved phenolic resins

Twenty seven addition cured phenolic resin compositions were prepared and tested for their ability to give char residues comparable to state-of-the-art phenolic resins. Cyanate, epoxy, allyl, acrylate, methacrylate and ethynyl derivatized phenolic oligomers were investigated. The novolac-cyanate and propargyl-novolac resins provided anaerobic char yields at 800 C of 58 percent. A 59 percent char yield was obtained from modified epoxy novolacs. A phosphonitrilic derivative was found to be effective as an additive for increasing char yields. The novolac-cyanate, epoxy-novolac and methacrylate-epoxy-novolac systems were investigated as composite matrices with Thornel 300 graphite fiber. All three resins showed good potential as composite matrices. The free radical cured methacrylate-epoxy-novolac graphite composite provided short beam shear strengths at room temperature of 93.3 MPa (13.5 ksi). The novolac-cyanate graphite composite produced a short beam shear strength of 74 MPa (10.7 ksi) and flexural strength of 1302 MPa (189 ksi) at 177 C. Air heat aging of the novolac-cyanate and epoxy novolac based composites for 12 weeks at 204 C showed good property retention

Portable Recovery System for an Unmanned Aircraft with a Straight Wing and a Tractor Propeller

The recovery system development effort for an unmanned aircraft (UA) has been documented and examined. The development effort existed to satisfy a customer's need to recover an 80 lb aircraft on unimproved terrain. The recovery system had to be able to be transported in a small portion of the bed of a pickup truck, set up in less than 15 minutes, and operated by highly tasked individuals. The customer was willing to accept impacts to aircraft performance, but impacts were to be minimized to the greatest extent possible. Multiple iterations of designs were developed and tested, starting from a previously established arresting wire recovery system design, evolving through many barrier net configurations. Testing was conducted by suspending an analogue aircraft from a truck-mounted aircraft recovery simulator mechanism, pushing an aircraft through the recovery system, launching an unpowered aircraft into the recovery system, and flying a fully functional aircraft into the recovery system during flight testing. The current design is a barrier system that secures the airframe and decelerates it via two disk brake dissipaters. All of the on-runway recoveries of the mature designs resulted in successful recoveries of the aircraft. Some of the off-runway recoveries resulted in damage to the aircraft. Design changes were implemented to avoid future malfunctions. Additional improvements are proposed for consideration

Comparing and theorizing state-diaspora relations

Alexandra Délano and Alan Gamle

1862-03-11 George A. Delano wishes reimbursement for caring for the ailing Franklin B. Chase at his public house

https://digitalmaine.com/cw_me_1st_cav/1225/thumbnail.jp

Selection of Web Services Based on Opinion Mining of Free-Text User Reviews

When multiple web services exist that perform identical tasks, non-functional attributes must be considered in order to choose the best service. Quality-of-service (QoS) attributes are often used to differentiate functionally redundant web services. However, ranking services according to QoS attributes is a complex problem. Additionally, the use of test data to establish those QoS ratings does not always yield accurate results. Therefore, this paper proposes a method that utilizes opinion mining techniques to extract information about the QoS attributes of a web service based on free-text user reviews. This method not only has the advantage of using real-world data rather than test data, but it also ensures that a variety of use cases are tested that would be common in the everyday usage of that service

Monitoring Relative Abundance of American Shad in Virginia Rivers 2005 Annual Report

Concern about the decline in landings of American shad (Alosa sapidissima) along the Atlantic coast prompted the development of an interstate fisheries management plan (FMP) under the auspices of the Atlantic States Marine Fisheries Management Program (ASMFC 1999). Legislation enables imposition of federal sanctions on fishing in those states that fail to comply with the FMP. To be in compliance, coastal states are required to implement and maintain fishery-dependent and fishery-independent monitoring programs as specified by the FMP. For Virginia, these requirements include spawning stock assessments, the collection of biological data on the spawning run (e.g., age-structure, sex ratio, and spawning history), estimation of total mortality, indices of juvenile abundance, and evaluation of restoration programs by detection and enumeration of hatchery-released fish. This annual report documents continued compliance with Federal law. Since 1998, scientists at the Virginia Institute of Marine Science have monitored the spawning run of American shad in the James, York and Rappahannock rivers. The information resulting from this program is reported annually to the ASMFC, has formed the basis for a significant number of technical papers published in the professional literature, and is contributing substantially to our understanding of the status and conservation of this important species. Data collected in the Virginia monitoring program was recently used in a revised stock assessment of American shad scheduled for peer review in summer 2007. A number of individuals make significant contributions to the monitoring program and the preparation of this report. Commercial fishermen Tony Kellum, Raymond Kellum, Marc Brown and Jamie Sanders construct, set, and fish the sampling gear and offer helpful advice. They have participated in the sampling program since its beginning in 1998. Their contributions as authors of historic log books during the 1980s and as expert shad fishermen are essential elements of the monitoring program. In 2006, the staff and students of the Virginia Institute of Marine Science who participated in the program were: K. Delano, B. Watkins, P. Crewe, A. Rhea, R. Harris, J. Hoffman, T. Tuckey, A. Aunins, S. Upton, and M. Chattin. Their dedication, consistent attention to detail and hard work in the field and in the laboratory are appreciated. K. Delano prepared data summaries for this report and B. Watkins determined age s of fish. Fish product from the sentinel fishery are donated to the Food Bank of Newport News, Virginia. We offer our thanks to Mr. Bud Davenport who facilitates this donation and to the Hunters for the Hungry (Virginia Hunters Who Care) organization for their assistance

Comparative analysis of rigidity across protein families

We present a comparative study in which 'pebble game' rigidity analysis is applied to multiple protein crystal structures, for each of six different protein families. We find that the main-chain rigidity of a protein structure at a given hydrogen bond energy cutoff is quite sensitive to small structural variations, and conclude that the hydrogen bond constraints in rigidity analysis should be chosen so as to form and test specific hypotheses about the rigidity of a particular protein. Our comparative approach highlights two different characteristic patterns ('sudden' or 'gradual') for protein rigidity loss as constraints are removed, in line with recent results on the rigidity transitions of glassy networks

The Liquidus Temperature for Methanol-Water Mixtures at High Pressure and Low Temperature, with Application to Titan

Methanol is a potentially important impurity in subsurface oceans on Titan and Enceladus. We report measurements of the freezing of methanol-water samples at pressures up to 350~MPa using a volumetric cell with sapphire windows. For low concentrations of methanol, the liquidus temperature is typically a few degrees below the corresponding ice freezing point, while at high concentrations it follows the pure methanol trend. In the Ice-III regime, we observe several long-lived metastable states. The results suggest that methanol is a more effective antifreeze than previously estimated, and might have played an important role in the development of Titan's subsurface ocean

Long-term efficiency of cataract surgery with hydrophilic acrylic Ioflex intraocular lens

OBJECTIVE: To evaluate the efficiency of long-term cataract surgery using low-cost intraocular lens implantation in community campaigns. METHODS: Fifty-eight randomly selected patients were evaluated four years after phacoemulsification and Ioflex intraocular lens implantation. Causes of low visual acuity related to the intraocular lens were evaluated, and treatment costs were calculated. RESULTS: The mean age of patients was 72±10.2 years. Four years after surgery, 25 eyes (43.0%) had decreased visual acuity related to the intraocular lens: posterior capsule opacification was noted in 24 eyes (41.3%), and intraocular lens opacification was noted in one eye (1.7%). The total cost of the post-surgical complication treatments represented 6.3% of the initial budget of the entire surgical patient group. CONCLUSIONS: The efficiency of cataract surgery with low-cost Ioflex intraocular lens implantation was significantly reduced in a long-term follow-up study because postoperative complications related to intraocular lenses emerged at higher rates than when the gold-standard treatment was used