Testing of the LSST's photometric calibration strategy at the CTIO 0.9 meter telescope

The calibration hardware system of the Large Synoptic Survey Telescope (LSST) is designed to measure two quantities: a telescope's instrumental response and atmospheric transmission, both as a function of wavelength. First of all, a "collimated beam projector" is designed to measure the instrumental response function by projecting monochromatic light through a mask and a collimating optic onto the telescope. During the measurement, the light level is monitored with a NIST-traceable photodiode. This method does not suffer from stray light effects or the reflections (known as ghosting) present when using a flat-field screen illumination, which has a systematic source of uncertainty from uncontrolled reflections. It allows for an independent measurement of the throughput of the telescope's optical train as well as each filter's transmission as a function of position on the primary mirror. Second, CALSPEC stars can be used as calibrated light sources to illuminate the atmosphere and measure its transmission. To measure the atmosphere's transfer function, we use the telescope's imager with a Ronchi grating in place of a filter to configure it as a low resolution slitless spectrograph. In this paper, we describe this calibration strategy, focusing on results from a prototype system at the Cerro Tololo Inter-American Observatory (CTIO) 0.9 meter telescope. We compare the instrumental throughput measurements to nominal values measured using a laboratory spectrophotometer, and we describe measurements of the atmosphere made via CALSPEC standard stars during the same run

SURFACE TREATMENT FOR THE MITIGATION OF WHEY PROTEIN FOULING

Heat transfer fouling experiments were carried out in a temperature controlled stirred vessel using aqueous solutions of whey protein concentrate in the concentration range of 3 to 3.5 wt-% at a bulk temperature of 50 °C and pH of 6. Heat transfer data were obtained from thermocouples embedded in an immersed electrical heating rod with various metal plates attached with-and-without surface treatments. Measurements included solution temperature, heating element surface temperature, and heat duty. Results are presented as fouling resistance versus time for aluminum, copper, stainless steel, electro-polished stainless steel, and surfaces coated with DLC and doped with Si , SiO, as well as DLC-coating of an electro-polished stainless steel. Reducing surface roughness was found to mitigate fouling but the combination of both surface treatments, DLC coatings, and electro-polishing gave the best performance. The experimental results demonstrate the potential and value for reducing the adhesive behavior of whey protein fouling layers using modified surfaces. Also a comparison of these results with those for crystallization fouling show the same effects of the surface modification on nucleation and crystal growth. Of particular importance is the influence on the cleaning performance where the main potential can be expected

EXTENDING THE INDUCTION PERIOD OF CRYSTALLIZATION FOULING THROUGH SURFACE COATING

To minimize the negative effects of scale formation in heat exchangers, new anti-fouling strategies are focusing on the modification of heat transfer surfaces. These modifications should lead to tailored made surfaces for different technical applications. Aim of this surface modification is the extension of the induction period to minimize the negative effects of fouling and maximize the endurance of the heat exchanger. To achieve such, different surface coatings on stainless steel were investigated in respect of fouling tendency. The effect of flow velocity respectively Reynolds number on the induction time of CaSO4 crystallization fouling were tested in different test units. Diamond like carbon coatings are extending the induction time in every measured flow velocity. At higher Reynolds numbers, the effect of different surface crystallization due to energetic modification is reduced because of the dominating effect of the low adhesive surface. Thus the induction time can be extended by the factor of 2 for low fluid velocities (DLC or SICON®) and more than 20 for higher Reynolds numbers (DLC and SICON®). The combination of limited nucleation spots due to electro-chemical treatment of the substrate before coating can be a tailored made surface with maximum induction time for crystallization fouling

INFLUENCE OF DIFFERENT SURFACE MATERIALS ON NUCLEATION AND CRYSTAL GROWTH IN HEAT EXCHANGERS

The influence of different materials on the fouling tendency in saline calcium sulfate solution was investigated. The effects of the untreated material on the crystallization process have been studied experimentally in the micro- and macroscopic scale. The crystallization in the induction period was visualized with SEM and AFM to locate preferred nucleation spots and to visualize the crystal growth. The different materials are showing different crystal growth behavior (number and size of the crystals). These results are corresponding with the macroscopic fouling results with limited shear stress. Also different roughness values on stainless steel have been studied with respect to fouling tendency. The induction time can be extended with smoother surfaces due to the limitation of nucleation spots. With higher fluid velocities, the adhesion of the forming crystals on the heat transfer surface dominates the length of the induction time

Examination of the value of community water fluoridation

Millions worldwide are affected by dental caries, which impacts the global economy and public health. Robust evidence demonstrates that water fluoridation prevents dental caries. However, there is evidence that high doses of fluoride can cause negative side effects. A literature review was conducted further to support reported evidence of the advantages of adopting water fluoridation at the community level. The economic evaluation of community water fluoridation highlighted the local cost savings by comparing it with the cost of disease prevention. Cumulative data revealed that dental issues prevention and economic benefits were highlighted in 38.6% of the research reported in the literature. The Pearson's chi-square test with Yates' continuity correction between economic benefits of fluoridation and dental issues helped identify the association between the two variables. The p-value of 0.0378 and X-squared=4.3141 show a strong correlation between dental issues in current research and demonstrate how curbing issues with increased community fluoridation can be economically beneficial. The review justifies findings that community water fluoridation can avert direct and indirect costs and help reduce dental ailments. The study further presents support for the finding that the return on investment regarding community water fluoridation depends on several factors including the size of the community, factors effecting health equality, and proper management and regulation of the fluoridation process. This study had limitations owing to the fact that the data being utilized from published reports came primarily from developed countries, resulting in a risk of cultural bias and lacking generalizability

Gluten Uses and Food Industry Needs

Established and supported under the Australian Government’s Cooperative Research Centre Progra

Improving Gluten Production: Development of a New Salt-Washing Process

Established and supported under the Australian Government’s Cooperative Research Centre Progra