67 research outputs found
Phase 9 Fiber Optic Cable Microbending and Temperature Cycling Tests
Optical fibers represent the back bone of the current communications networks. Their performance in the field lacks long term testing data because of the continuous evolution of the manufacturing of fibers and cables. An optical fiber cable that is installed in NASA's KSC has experienced a dramatic increase in attenuation after three years of use from 0.7 dB/km to 7 dB/km in some fibers. A thorough study is presented to assess the causes of such an attenuation increase. Material and chemical decomposition testing showed that there are no changes in the composition of the fiber which might have caused the increase in attenuation. Microbending and heat cycling tests were performed on the cable and individual fibers. It was found that the increase in attenuation is due to microbending caused by excessive stress exerted on the fibers. This was the result of manufacturing and installation irregularities
2022 Upgrade and Improved Low Frequency Camera Sensitivity for CMB Observation at the South Pole
Constraining the Galactic foregrounds with multi-frequency Cosmic Microwave
Background (CMB) observations is an essential step towards ultimately reaching
the sensitivity to measure primordial gravitational waves (PGWs), the sign of
inflation after the Big-Bang that would be imprinted on the CMB. The BICEP
Array telescope is a set of multi-frequency cameras designed to constrain the
energy scale of inflation through CMB B-mode searches while also controlling
the polarized galactic foregrounds. The lowest frequency BICEP Array receiver
(BA1) has been observing from the South Pole since 2020 and provides 30 GHz and
40 GHz data to characterize the Galactic synchrotron in our CMB maps. In this
paper, we present the design of the BA1 detectors and the full optical
characterization of the camera including the on-sky performance at the South
Pole. The paper also introduces the design challenges during the first
observing season including the effect of out-of-band photons on detectors
performance. It also describes the tests done to diagnose that effect and the
new upgrade to minimize these photons, as well as installing more dichroic
detectors during the 2022 deployment season to improve the BA1 sensitivity. We
finally report background noise measurements of the detectors with the goal of
having photon noise dominated detectors in both optical channels. BA1 achieves
an improvement in mapping speed compared to the previous deployment season.Comment: Proceedings of SPIE Astronomical Telescopes + Instrumentation 2022
(AS22
Deep inelastic inclusive and diffractive scattering at values from 25 to 320 GeV with the ZEUS forward plug calorimeter
Deep inelastic scattering and its diffractive component, , have been studied at HERA with the ZEUS
detector using an integrated luminosity of 52.4 pb. The method has
been used to extract the diffractive contribution. A wide range in the
centre-of-mass energy (37 -- 245 GeV), photon virtuality (20 -- 450
GeV) and mass (0.28 -- 35 GeV) is covered. The diffractive cross
section for GeV rises strongly with , the rise becoming
steeper as increases. The data are also presented in terms of the
diffractive structure function, , of the proton. For fixed
and fixed , \xpom F^{\rm D(3)}_2 shows a strong rise as \xpom \to
0, where \xpom is the fraction of the proton momentum carried by the
Pomeron. For Bjorken-, \xpom F^{\rm D(3)}_2 shows
positive scaling violations, while for
negative scaling violations are observed. The diffractive structure function is
compatible with being leading twist. The data show that Regge factorisation is
broken.Comment: 89 pages, 27 figure
Analysis and Design of a New Dual Band Microstrip Patch Antenna Based on Slot Matching Y-Shaped
A new compact microstrip slot antenna with Y-shaped coupling aperture is proposed. This antenna is based on a rectangular form with a microstrip fed line for excitation, and consists of slots on the edge of the radiation patch to provide dual-band operation. The design and simulation of the antenna were performed using CST Microwave Studio simulator. A prototype of the proposed antenna has been constructed and tested. In order to validate the return loss of the prototype antenna, the experimental results are presented. The results show two available bands with –10 dB band S at 2.7 GHz and band C at 5 GHz. Also, good radiation performance and antenna gain over the two frequency ranges have been obtained. Computation results confirm the experimental findings
Emoji alter the perception of emotion in affectively neutral text messages
Previous studies of emoji effects on text sentiment demonstrate mixed findings. Further, these studies are limited by confounds, e.g., underlying text sentiment, lack of ecological validity. We considered emoji effects on the emotional valence of affectively neutral English-language text messages. We additionally considered differences across US-American, British, and Danish participants. 217 participants considered screenshots of question-and-response text message exchanges with/without emoji, in a 4 (emoji type: no emoji, negative, neutral, positive) × 3 (nationality: American, British, Danish) mixed-factors design. Cumulative link mixed-effects models demonstrated that messages + negative emoji were rated more-negatively than any other emoji conditions. Responses + positive emoji were rated more-positively than any other emoji condition. Responses + neutral emoji and responses without emoji were perceived as equally emotive. There was no emoji type × nationality interaction, suggesting that emoji effects were consistent across participants. Findings are considered viz linguistic processing, social interactions, education, marketing, and public health interventions
Experimental and numerical study of chemiluminescent species in low-pressure flames
Kathrotia T, Riedel U, Seipel A, Moshammer K, Brockhinke A. Experimental and numerical study of chemiluminescent species in low-pressure flames. APPLIED PHYSICS B. 2012;107(3):571-584
Deposition and derivation of clastic carbonates on a Mesozoic continental margin, Othris, Greece
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