2,544 research outputs found
Study on the effect of contamination on the performance of X-ray telescopes
Modifications were made to the X-ray reflectometer located at the Space Sciences Laboratory, Marshall Space Flight Center. One was an automatic drive for the Large Micrometer Head. This system, interfaced with the Hewlett Packard Computer System, is used to record data and provides the X-ray reflectometer with an automated data-taking capability. Using this system, a complete scatter curve can be obtained automatically. Previously, it was necessary to manually reset the system after recording for each data point in the scatter curve. The second modification provided an externally controlled electrical drive to move the microfocus X-ray source along its axis. With this modification, one can translate the X-ray source while it is operating to locate the position providing maximum count rate
A laboratory program to develop improved grazing incidence X-ray optics
Grazing incident double reflection X-ray telescop
Evidence that process simulations reduce anxiety in patients receiving dental treatment: randomized exploratory trial
Process simulations – mental simulations that ask people to imagine the process of completing a task – have been shown to decrease anxiety in students facing hypothetical or psychological threats in the short term. The aim of the present study was to see whether process simulations could reduce anxiety in a sample of the general population attending a dental practice, and whether these effects could be sustained throughout treatment. Participants (N = 75) were randomized to an experimental condition where they were asked to simulate mentally the process of seeing the dentist, or to a control condition where they were asked to simulate mentally the outcome of seeing the dentist. Findings showed that participants in the experimental condition were significantly less anxious both before and after their consultations. Self-efficacy and self-esteem remained unchanged. This study suggests that process simulation is one active ingredient in anxiety treatment programs and further research is required to enhance its effects
Genetic variability of forage grass cultivars: A comparison of Festuca pratensis Huds., Lolium perenne L., and Dactylis glomerata L.
Three widely used cultivars of each of the species Festuca pratensis Huds., Lolium perenne L., and Dactylis glomerata L. were investigated by means of randomly amplified polymorphic DNA (RAPD) markers and vegetative growth traits in order to investigate genetic variability within each cultivar and to compare the level of diversity among cultivars and species. RAPD markers allowed a clear separation of the three species. Genetic variability based on RAPD markers was considerably lower for F. pratensis cultivars than for L. perenne and D. glomerata cultivars which showed similar levels of variability. The proportion of variability due to variation within cultivars, determined by an analysis of molecular variance, was lower in F. pratensis (64.6%) than in L. perenne (82.4%) and D. glomerata (85.1%). A comparison of F. pratensis and L. perenne, based on vegetative growth traits, confirmed the differences in genetic variability within cultivars. F. pratensis showed lower coefficients of genetic variation for eight of ten traits when compared to L. perenne. This study demonstrates considerable differences in genetic variability which may have consequences for the adaptability and persistency of individual cultivars
Pengaruh Gaya Kepemimpinan Transformasional Dan Transaksional Terhadap Kepuasan Kerja Karyawan (Studi Pada CV Kalingga Jaya Di Jakarta)
This research aims to examine and explain the effect of partially or simultaneously transformational and transactional leadership style on employee job satisfaction in CV Kalinga Jaya by using multiple regression analysis. The type of research used in this research is an explanatory research with a quantitative approach. Instruments in this study using a questionnaire that was distributed to employees Kalingga Jaya CV. Results from this study explains that there are significant partial and simultaneous among Transformational Leadership Style and Transactional Leadership Style on Job Satisfaction as measured by multiple regression analysis. Results of the analysis is also known that Transactional leadership style has significant influence partially on Employee Satisfaction Jaya CV Kalingga. The phenomenon can be concluded that the average employee criteria in Kalinga Jaya CV is the type of employees who expect a little risk in the work and it is difficult to get out of the comfort zone and working conditions like these can be created by the Transactional Leadership Style. According to research conducted by Leadership Style Bass that the private sector is more inclined to Transactional Leadership Styles
The Daily Consequences of Widowhood: The Role of Gender and Intergenerational Transfers on subsequent Housework Performance
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142738/1/Nesse-Carr-House_Perf-JFI-2004.pd
Estimating usual intakes mainly affects the micronutrient distribution among infants, toddlers and pre-schoolers from the 2012 Mexican National Health and Nutrition Survey
Abstract Objective To compare estimates from one day with usual intake estimates to evaluate how the adjustment for within-person variability affected nutrient intake and adequacy in Mexican children. Design In order to obtain usual nutrient intakes, the National Cancer Institute’s method was used to correct the first 24 h dietary recall collected in the entire sample ( n 2045) with a second 24 h recall collected in a sub-sample ( n 178). We computed estimates of one-day and usual intakes of total energy, fat, Fe, Zn and Na. Setting 2012 Mexican National Health and Nutrition Survey. Subjects A total of 2045 children were included: 0–5·9 months old ( n 182), 6–11·9 months old ( n 228), 12–23·9 months old ( n 537) and 24–47·9 months old ( n 1098). From these, 178 provided an additional dietary recall. Results Although we found small or no differences in energy intake (kJ/d and kcal/d) between one-day v . usual intake means, the prevalence of inadequate and excessive energy intake decreased somewhat when using measures of usual intake relative to one day. Mean fat intake (g/d) was not different between one-day and usual intake among children >6 months old, but the prevalence of inadequate and excessive fat intake was overestimated among toddlers and pre-schoolers when using one-day intake ( P< 0·05). Compared with usual intake, estimates from one day yielded overestimated prevalences of inadequate micronutrient intakes but underestimated prevalences of excessive intakes among children aged >6 months. Conclusions There was overall low variability in energy and fat intakes but higher for micronutrients. Because the usual intake distributions are narrower, the prevalence of inadequate/excessive intakes may be biased when estimating nutrient adequacy if one day of data is used
Revisiting (some of) the Lasting Impacts of the Liberty Ships Via A Metallurgical Analysis of Rivets from the SS John W. Brown
During World War II, 2710 Liberty ships were built in the United States across 18 ship yards. The rate of production of these ships was at a scale not previously witnessed, reflecting a strategic marshaling of national assets critical to the war effort. For the metallurgist, metallurgical engineer, or materials scientist, these ships also struck commanding images regarding their catastrophic failures. The study of these failures led to increased understanding of brittle fracture, fracture mechanics, and ductile-to-brittle transition temperatures. The post-mortem studies of Liberty ships highlighted the importance of composition and microstructure in controlling the properties of steel in fracture-critical applications. This study examines a rivet from the SS “John W. Brown”, which was assembled in Baltimore, Maryland, and launched in September 1942, The “John W. Brown” was restored between 1988 and 1991. Classical metallurgical analysis of a rivet from the original 1942 vessel is compared with modern rivets used during its restoration. The rivets provide an analogue to the plate material used in these ships. A comparison of these materials is presented along with a discussion of the importance of composition–microstructure–property relationships that concomitantly evolved
Oxidation behavior and microstructural evolution of Ti-6Al-4V and Ti-6Al-4V-1B sheet
A direct comparison between the oxidation behavior of Ti-6Al-4V and Ti-6Al-4V + 1B has been conducted to elucidate whether the addition of boron to Ti-6Al-4V impacts the oxidation behavior. Industrially prepared sheet of Ti-6Al-4V and Ti-6Al-4V + 1B were oxidized at temperatures between 650 and 950 °C for holding times of 25 and 50 h. Weight-gain measurements and characterization of surface and near-surface microstructures showed that the addition of 1 wt% B increased the material’s oxidation resistance. Additionally, the ingress of oxygen tends to decrease the solubility of other alloying species in α-Ti and leads to the formation of a distinctive and atypical microstructure with a distinct morphology
Oxidation behavior and microstructural evolution of Ti-6Al-4V and Ti-6Al-4V-1B sheet
A direct comparison between the oxidation behavior of Ti-6Al-4V and Ti-6Al-4V + 1B has been conducted to elucidate whether the addition of boron to Ti-6Al-4V impacts the oxidation behavior. Industrially prepared sheet of Ti-6Al-4V and Ti-6Al-4V + 1B were oxidized at temperatures between 650 and 950 °C for holding times of 25 and 50 h. Weight-gain measurements and characterization of surface and near-surface microstructures showed that the addition of 1 wt% B increased the material’s oxidation resistance. Additionally, the ingress of oxygen tends to decrease the solubility of other alloying species in α-Ti and leads to the formation of a distinctive and atypical microstructure with a distinct morphology
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