Some effects of thermal-cycle-induced deformation in rocket thrust chambers

The deformation process observed in the hot gas side wall of rocket combustion chambers was investigaged for three different liner materials. Five thrust chambers were cycled to failure by using hydrogen and oxygen as propellants at a chamber pressure of 4.14 MN/cu m. The deformation was observed nondestructively at midlife points and destructively after failure occurred. The cyclic life results are presented with an accompanying discussion about the problems of life prediction associated with the types of failures encountered in the present work. Data indicating the deformation of the thrust chamber liner as cycles are accumulated are presented for each of the test thrust chambers. From these deformation data and observation of the failure sites it is evident that modeling the failure process as classic low cycle thermal fatigue is inadequate as a life prediction method

Design considerations and test facilities for accelerated radiation effects testing

Test design parameters for accelerated dose rate radiation effects tests for spacecraft parts and subsystems used in long term mission (years) are detailed. A facility for use in long term accelerated and unaccelerated testing is described

The role of right and left parietal lobes in the conceptual processing of numbers

Neuropsychological and functional imaging studies have associated the conceptual processing of numbers with bilateral parietal regions (including intraparietal sulcus). However, the processes driving these effects remain unclear because both left and right posterior parietal regions are activated by many other conceptual, perceptual, attention, and response-selection processes. To dissociate parietal activation that is number-selective from parietal activation related to other stimulus or response-selection processes, we used fMRI to compare numbers and object names during exactly the same conceptual and perceptual tasks while factoring out activations correlating with response times. We found that right parietal activation was higher for conceptual decisions on numbers relative to the same tasks on object names, even when response time effects were fully factored out. In contrast, left parietal activation for numbers was equally involved in conceptual processing of object names. We suggest that left parietal activation for numbers reflects a range of processes, including the retrieval of learnt facts that are also involved in conceptual decisions on object names. In contrast, number selectivity in right parietal cortex reflects processes that are more involved in conceptual decisions on numbers than object names. Our results generate a new set of hypotheses that have implications for the design of future behavioral and functional imaging studies of patients with left and right parietal damage

Effective thermal conductivities of four metal ceramic composite coatings in hydrogen-oxygen rocket firings

An experimental investigation was conducted to determine the effective conductivities of four plasma-arc-sprayed, metal-ceramic gradated coatings on hydrogen-oxygen thrust chambers. The effective thermal conductivities were not a function of pressure or oxidant-to-fuel ratio. The various materials that made up these composites do not seem to affect the thermal conductivity values as much as the differences in the thermal conductivities of the parent materials would lead one to expect. Contact resistance evolving from the spraying process seems to be the controlling factor. The thermal conductivities of all the composites tested fell in the range of 0.75 to 7.5 watts per meter kelvin

Reliability and effective thermal conductivity of three metallic-ceramic composite insulating coatings on cooled hydrogen-oxygen rockets

An experimental investigation of the structural integrity and effective thermal conductivity of three metallic-ceramic composite coatings was conducted. These coatings were plasma sprayed onto the combustion side of water-cooled, 12.7-centimeter throat diameter, hydrogen-oxygen rocket thrust chambers operating at 2.07 to 4.14 meganewtons per square meter chamber pressure. The metallic-ceramic composites functioned for six to 17 cycles and for as long as 213 seconds of rocket operations and could have probably provided their insulating properties for many additional cycles. The effective thermal conductivity of all the coatings was in the range of 0.7472 to 4.483 w/(m)(K), which makes the coatings a very effective thermal barrier. Photomicrographic studies of cross-sectioned coolant tubes seem to indicate that the effective thermal conductivity of the coatings is controlled by contact resistance between the particles, as a result of the spraying process, and not the thermal conductivity of the bulk materials

Design considerations for a LORAN-C timing receiver in a hostile signal to noise environment

The environment in which a LORAN-C Timing Receiver may function effectively depends to a large extent on the techniques utilized to insure that interfering signals within the pass band of the unit are neutralized. The baseline performance manually operated timing receivers is discussed and the basic design considerations and necessary parameters for an automatic unit utilizing today's technology are established. Actual performance data is presented comparing the results obtained from a present generation timing receiver against a new generation microprocessor controlled automatic acquisition receiver. The achievements possible in a wide range of signal to noise situations are demonstrated

The impact of poor asthma control among asthma patients treated with inhaled corticosteroids plus long-acting β2-agonists in the United Kingdom : a cross-sectional analysis

This study was sponsored by Boehringer Ingelheim Ltd UK, which was involved in all stages of the study conduct and analysis and also funded all costs associated with the development of the manuscript. The authors acknowledge Kantar Health and Errol J Philip for providing medical writing support. Editorial assistance and medical writing support was also provided by Michelle Rebello, PhD, and Suchita Nath-Sain, PhD, of Cactus Communications. This study was sponsored by Boehringer Ingelheim Ltd., UK, which also funded all costs associated with the development of the manuscript. Author Correction, npj Primary Care Respiratory Medicine 27, Article number: 65 (2017) doi:10.1038/s41533-017-0063-5, 05 December 2017 Correction to:npj Primary Care Respiratory Medicine (2017); doi:10.1038/s41533-017-0014-1; Published 09 March 2017Peer reviewedPublisher PD

Archeological Significance Testing at Sites 41MU54, 41MU55, and 41MU57, Montague County, Texas with A Data Recovery Plan for Site 41MU55

The Texas Department of Transportation (TxDOT) conducted archeological significance testing at Sites 41MU54, 41MU55, and 41MU57, which are within the right-of-way of proposed road FM 677 between Illinois Bend, a community in Montague County, Texas, and a proposed bridge crossing the Red River at a location south of Courtney, a community in Love County, Oklahoma. As the construction will connect with a bridge that will be built with partial federal funding, the testing was undertaken under the guidelines of the National Historic Preservation Act of 1966 and its implementing regulations, 36CFR, Part 800, and the National Environmental Policy Act. At Site 41MU54, a total of 74 work-hours was spent on hand-excavation of five square meters. No cultural remains were located, and the site is considered not significant. No additional research is recommended for this site. At Site 41MU55, 107 work-hours were spent on the hand-excavation of approximately eight square meters. Both historic and prehistoric components were identified. The historic component apparently represented casual disposal of household refuse during the first half of the twentieth century and is considered not significant. The prehistoric component appears to represent a single occupation or event, probably dating to the Late Archaic time period. However, no diagnostic artifacts were recovered. The lower part of the prehistoric deposit, perhaps 15 to 20 cm thick, appears to be intact, and four features, identified as hearths, were located. Because of the presence of intact features within an apparent discrete Late Archaic component it is believed that this site is significant. Therefore, additional research is proposed for this site prior to construction, and the report includes a proposed data recovery plan. At Site 41MU57, 72 work-hours were spent excavating five square meters by hand and three trenches, each approximately 14 meters in length, by backhoe. Excavations revealed a very sparse lithic scatter confined to near surface deposits, and probably representing the remains of a small hunting camp which provided a good vantage point over the adjacent Red River floodplain. Because of erosion, the remains are almost certainly located within disturbed soils forming on deflated surfaces. No diagnostic artifacts were located. The site is believed to be not significant, and no additional research is recommended for this site

Archeological Significance Testing at Site 41SR191, Starr County, Texas

The Texas Department of Transportation (TxDOT) conducted archeological significance testing at Site 41SR191, within the right-of-way of proposed improvements to US 83 in Starr County. The site was recorded in 1991 during an archeological survey of additional rights-of-way required for highway improvements. At that time, the site was recorded as a surface scatter of burned rock fragments and lithic debitage in a fallow field, covering an area approximately 50 meters east-west by 150 meters north-south. Although it was thought that the site was unlikely to yield substantial significant information, the site was considered to be one of the two (out of a total of 25 recorded during the survey) most likely to yield significant information. Thus, additional testing was recommended for this site as the project involves federal funding. As the improvements will utilize federal funding, the testing was undertaken under the guidelines of the National Historic Preservation Act of 1966 and its implementing regulations, 36CFR, Part 800, and the National Environmental Policy Act. A total of 120 work-hours was spent on hand-excavation of eight square meters and machine excavation of two trenches, each approximately 40 meters in length and two meters in depth. The testing yielded only five prehistoric biface fragments, none of which was temporally or culturally diagnostic, and relatively small quantities of lithic debitage, all confined within approximately 30 cm of the surface. Historic artifacts were found throughout the same depths of deposit. Thus, it was concluded that the site was extremely disturbed by historic land clearing and cultivation activities, and that the site was unlikely to yield any significant information. It is recommended that no additional cultural resources investigations be carried out at the site, and that the project be allowed to proceed

Significance Testing at Sites 41FY170 and 41FY509, Fayette County, Texas

The State Department of Highways and Public Transportation (SDHPT) conducted archaeological significance testing at Sites 41FY170 and 41FY509 which are within the right-of-way proposed improvements to State Highway 71 in the vicinity of Plum, a community in Fayette County. As the construction will use federal funding, the testing was undertaken under the guidelines of the National Historic Preservation Act of 1966 and its implementing regulations, 36CFR, Part 800, and the National Environmental Policy Act. Testing at Site 41FY170 revealed both prehistoric and historic artifacts. The prehistoric artifacts, none of which are temporally or culturally diagnostic, indicate that the area was used for the selection and preliminary reduction of chert gravels which occur naturally on the ridge. No stratification within the cultural zone was observed, nor were any cultural features observed. The historic artifacts appear to represent a thin sheet midden of domestic remains, probably dating to the late 1800s and associated with a historic structure on the property. Test excavations at Site 41FY509 revealed large quantities of cultural debris. However, most consisted of lithic fragments which could not be associated with a particular temporal period or specific cultural group; and those few artifacts that were temporally diagnostic indicated that the site had been occupied (at least intermittently) over a long period of time (from the Paleoindian/Archaic Transition through the Neoarchaic), and that there was neither stratigraphic nor horizontal separation of artifacts from different time periods. No cultural features were located. Based on the results of the test excavations and subsequent laboratory analysis of recovered materials, neither of the sites is considered to meet the criteria for significance defined in 36CFR, Part 60.4. Based on these assessments, no additional cultural research is recommended prior to construction activities. Although there is little or no probability for the presence of significant areas of undisturbed buried cultural remains, there is a slight possibility that small, isolated cultural features may still be present within the area, and thus such features may be encountered during earth-moving operations. Machine operators/supervisors should be alerted to the possibility of such features. If features are encountered, construction should be stopped until qualified archaeologists have had an opportunity to assess the remains. The probability of encountering such remains is considered too low to warrant archaeological monitoring