The Alternating Surface Segmented Lap Joint: a Design for Thin Highly Loaded Joints

The combination of thin airfoil sections and high aerodynamic loads on many wind tunnel models presents a major problem for attachment of flap elements. Conventional methods of attaching fixed control elements such as lap and tongue-in-groove joints are not rigid enough to provide surface continuity required in high Reynolds number research. For the extreme cases, the solution has been to fabricate separate wings for each flap setting with the flap element being and integral part of the wing. Here an attractive solution to this problem, the alternating surface segmented lap joint, is discussed. This joint provides increased rigidity and lower stress levels than conventional joints. Additionally, attachment fastener loading is low and the joint can be designed to accommodate high shear levels due to bending without the use of dowel pins

Investigation of Low-temperature Solders for Cryogenic Wind Tunnel Models

The advent of high Reynolds number cryogenic wind tunnels has forced alteration of manufacturing and assembly techniques and eliminated usage of many materials associated with conventional wind tunnel models. One of the techniques affected is soldering. Solder alloys commonly used for wind tunnel models are susceptible to low-temperature embrittlement and phase transformation. The low-temperature performance of several solder alloys is being examined during research and development activities being conducted in support of design and fabrication of cryogenic wind tunnel models. Among the properties examined during these tests are shear strength, surface quality, joint stability, and durability when subjected to dynamic loading. Results of these tests and experiences with recent models are summarized

G94-1207 Scab of Wheat

The identification of and disease cycle of wheat scab is described along with its management. Guidelines for using wheat contaminated with vomitoxin also are included. Scab or Fusarium head blight is an important disease of wheat, barley, oats, rye and wheatgrasses. Scab manifests itself by the premature death or blighting of spikelets in the wheat head. Direct yield losses are often minor, but can be higher than 50 percent in severely infected fields. The economic significance is magnified by the possibility that the low quality, shriveled grain also can become contaminated by mycotoxins (e.g. vomitoxin, zearalenone)

Foliage Plants for Removing Indoor Air Pollutants from Energy-efficient Homes

No abstract availabl

G92-1097 Root and Crown Rot: Winterkill Complex of Winter Wheat

Root and crown rot--winterkill complex is discussed, including nature of the complex, symptoms, control, and management rationale. Root and crown rot of winter wheat is an interrelated disease complex caused by the interaction of infection of roots and crowns by Bipolaris sorokiniana and/or Fusarium graminearum and harsh winter conditions. It is an insidious, persistent and inconspicuous disease complex that reduces wheat yields each year. In extreme cases, entire fields or large areas within fields are killed. The ultimate effect is loss of stands, poor plant vigor, reduced yield and lower grain quality

Hachimoji DNA and RNA: A genetic system with eight building blocks

Reported here are DNA and RNA-like systems built from eight (hachi-) nucleotide letters (-moji) that form four orthogonal pairs. This synthetic genetic biopolymer meets the structural requirements needed to support Darwinism, including a polyelectrolyte backbone, predictable thermodynamic stability, and stereoregular building blocks that fit a Schrödinger aperiodic crystal. Measured thermodynamic parameters predict the stability of hachimoji duplexes, allowing hachimoji DNA to double the information density of natural terran DNA. Three crystal structures show that the synthetic building blocks do not perturb the aperiodic crystal seen in the DNA double helix. Hachimoji DNA was then transcribed to give hachimoji RNA in the form of a functioning fluorescent hachimoji aptamer. These results expand the scope of molecular structures that might support life, including life throughout the cosmos

Urinary F2-Isoprostanes and Metabolic Markers of Fat Oxidation

Metabolomic studies of increased fat oxidation showed increase in circulating acylcarnitines C2, C8, C10, and C12 and decrease in C3, C4, and C5. We hypothesize that urinary F2-isoprostanes reflect intensity of fatty acid oxidation and are associated with circulating C2, C8, C10, and C12 directly and with C3, C4, and C5 inversely. Four urinary F2-isoprostane isomers and serum acylcarnitines are quantified using LC-MS/MS within the Insulin Resistance Atherosclerosis Study nondiabetic cohort (n = 682). Cross-sectional associations between fasting urinary F2-isoprostanes (summarized as a composite index) and the selected acylcarnitines are examined using generalized linear models. F2-isoprostane index is associated with C2 and C12 directly and with C5 inversely: the adjusted beta coefficients are 0.109, 0.072, and −0.094, respectively (P \u3c 0.05). For these acylcarnitines and for F2- isoprostanes, the adjusted odds ratios (ORs) of incident diabetes are calculated from logistic regression models: the ORs (95% CI) are 0.77 (0.60–0.97), 0.79 (0.62–1.01), 1.18 (0.92–1.53), and 0.51 (0.35–0.76) for C2, C12, C5, and F2-isoprostanes, respectively.The direction of the associations between urinary F2-isoprostanes and three acylcarnitines (C2, C5, and C12) supports our hypothesis. The inverse associations of C2 and C12 and with incident diabetes are consistent with the suggested protective role of efficient fat oxidation

Geology of Niobrara State Park, Knox County, Nebraska, and Adjacent Areas, with a Brief History of the Park, Gavins Point Dam, and Lewis and Clark Lake

Location Niobrara State Park is located in northwestern Knox County, Nebraska, just west of the town of Niobrara and on the west side of the Niobrara River. The present park was opened in the summer of 1987. Mostly north of Nebraska Highway 12, the site is hilly with bluffs overlooking the Missouri and Niobrara rivers. Excellent facilities include paved roads, cabins, an outdoor swimming pooi, hiking trails, picnic and camping sites, horseback riding trails, playgrounds, restrooms, a group lodge, and an interpretive shelter. Many vantage points in the park have beautiful views of the lower Niobrara Valley and the middle Missouri Valley. Lovers of native plants and wildlife can see many different species in and near the park. Park grounds are open all year. The park office, about 1.5 miles northwest of the park entrance, is open daily from mid-April to mid-November, and weekdays at other times of the year (figs. 1 and 2). Purposes This educational circular describes the prehistory and history of Niobrara State Park, Gavins Point Dam and its reservoir-Lewis and Clark Lake-and several aspects of the geology of the park and nearby or adjoining areas. Sections include information on minerals, fossils, stratigraphy, and geologic history, but the principal focuses of this circular are on the work of and changes in the Niobrara River and on geologic hazards in the area. Cautions Caution is advised when visiting the park or any other area. A void walking on landslide areas. Stay away from steep hill slopes. Be careful when working on dark shale exposures on hot days because temperatures on these shales reach well above 100 degrees F. Poison ivy, stinging insects, and other such hazards occur. Be careful! We remind readers that collecting of any kind is prohibited in the park and that permission must be obtained from property owners before going on or collecting from private property

Spin-Peierls transitions in magnetic donor-acceptor compounds of tetrathiafulvalene (TTF) with bisdithiolene metal complexes

The spin-Peierls transition is considered as a progressive spin-lattice dimerization occurring below a transition temperature in a system of one-dimensional antiferromagnetic Heisenberg chains. In the simplest theories, the transition is second order and the ground state is a singlet with a magnetic gap. The historical origins and theoretical development of the concept are examined. Magnetic susceptibility and EPR measurements on the π-donor-acceptor compounds TTF·MS4C4(CF3)4 (M=Cu, Au; TTF is tetrathiafulvalene) are reported. These compounds exhibit clearly the characteristics of the spin-Peierls transition in reasonably good agreement with a mean-field theory. The susceptibility of each compound has a broad maximum near 50 K, while the transitions occur at 12 and 2.1 K for M=Cu and Au, respectively. EPR linewidth observations over a broad temperature range are examined. Areas for further experimental and theoretical work are indicated, and a critical comparison is made of related observations on other materials