Pad-Printing as a Fabrication Process for Flexible and Compact Multilayer Circuits

The purpose of this paper is to present a newly developed process for the fabrication of multilayer circuits based on the pad-printing technique. Even though the maturity level, in terms of accuracy, substrate type and print size of several printing industrial processes is relatively high, the fabrication complexity of multilayer printed electronics remains relatively high. Due to its versatility, the pad-printing technique allows the superposition of printed conductive and insulating layers. Compared to other printing processes, its main advantage is the ability to print on various substrates even on flexible, curved or irregular surfaces. Silver-based inks were used for the formulation of conductive layers while UV inks were employed to fulfil the functionality of the insulating layers. To demonstrate the functionality of the pad-printing results, a multilayer test pattern has been designed and printed on Kapton®. Furthermore, to demonstrate the efficacy of this approach, a multilayer circuit composed of three stacked layers has been designed and printed on various substrates including Kapton®, paper and wood. This electronic circuit controls an array of LEDs through the manipulation of a two-key capacitive touch sensor. This study, allowed us to define recommendations for the different parameters leading to high printing quality. We expect a long-term beneficial impact of this study towards a low-cost, fast, and environmental-friendly production of printed electronics.

effect of age and font on reading ability

To inform our knowledge of the typographical variables of stroke weight, letter width, and letter spacing, and their effects on different age groups and reading scenarios, we used Radner Reading Chart, where we measured reading speed at different sizes, to compare the fonts KBH Text, KBH Display, and Gill Sans Light. The experiment showed that for older participants, reading Gill Sans resulted in faster reading speed compared to KBH Text. However, Gill Sans could not be recognized at small sizes by either the younger or older participants. For critical print size (CPS), older participants were better at reading small print sizes at a regular reading speed when the text was set in KBH Text than when it was set in Gill Sans. The findings indicate that older readers are more sensitive to font legibility differences than younger readers. We discuss the implications of different reading scenarios putting different demands on the fonts as well as the perspective of older readers benefitting from certain visual qualities of fonts.

Simulating Visibility and Reading Performance in Low Vision

PurposeLow vision reduces text visibility and causes difficulties in reading. A valid low-vision simulation could be used to evaluate the accessibility of digital text for readers with low vision. We examined the validity of a digital simulation for replicating the text visibility and reading performance of low-vision individuals.MethodsLow-vision visibility was modeled with contrast sensitivity functions (CSFs) with parameters to represent reduced acuity and contrast sensitivity. Digital filtering incorporating these CSFs were applied to digital versions of the Lighthouse Letter Acuity Chart and the Pelli-Robson Contrast Sensitivity Chart. Reading performance (reading acuity, critical print size, and maximum reading speed) was assessed with filtered versions of the MNREAD reading acuity Chart. Thirty-six normally sighted young adults completed chart testing under normal and simulated low-vision conditions. Fifty-eight low-vision subjects (thirty with macular pathology and twenty-eight with non-macular pathology) and fifteen normally sighted older subjects completed chart testing with their habitual viewing. We hypothesized that the performance of the normally sighted young adults under simulated low-vision conditions would match the corresponding performance of actual low-vision subjects.ResultsWhen simulating low-vision conditions with visual acuity better than 1.50 logMAR (Snellen 20/630) and contrast sensitivity better than 0.15 log unit, the simulation adequately reduced the acuity and contrast sensitivity in normally sighted young subjects to the desired low-vision levels. When performing the MNREAD test with simulated low vision, the normally sighted young adults had faster maximum reading speed than both the Non-macular and Macular groups, by an average of 0.07 and 0.12 log word per minute, respectively. However, they adequately replicated the reading acuity as well as the critical print size, up to 2.00 logMAR of both low-vision groups.ConclusionA low-vision simulation based on clinical measures of visual acuity and contrast sensitivity can provide good estimates of reading performance and the accessibility of digital text for a broad range of low-vision conditions.

Increased letter spacing and greater letter width improve reading acuity in low vision readers

Low vision readers depend on magnification, but magnification reduces the amount of text that can be overviewed and hampers text navigation. In this study, we evaluate the effects that font variations letter spacing, letter width, and letter boldness have on low vision reading. We tested 20 low-vision patients with age-related macular degeneration (AMD) and used the Radner Reading Chart, which measures reading acuity (logRAD), maximum reading speed, and critical print size. The results demonstrated a small, but measurable effect of letter spacing and letter width on reading acuity near critical font sizes.

Differences in Graphomotor Skills by the Writing Medium and Children’s Gender

Factors of graphomotor skills may serve as indicators to determine a writer’s handwriting proficiency or acclimation to different writing surface textures. This study examines differences in children’s graphomotor skills based on types of writing medium and gender. Participants were 97 six-year-old Korean preschool children who had not received formal writing training prior to the study. Writing tasks were completed on a tablet screen and paper. Writing samples were analyzed using the Eye and Pen software to investigate spatial, temporal, and pressure exertion exhibited during the writing tasks. A repeated measures ANOVA revealed differences in graphomotor skills such as print size, writing speed, and writing pressure. Writing on a tablet screen decreased clarity of writing; print size and speed increased as the stylus slides across the tablet surface with relatively less friction, thereby decreasing the exertion of writing pressure. Analysis of writing differences according to gender indicated that boys generated larger print sizes than girls. Results suggest that while simple writing tasks may be feasible on the tablet screen, providing children with a larger writing medium and encouraging larger print sizes for writing practice, especially for boys, may be beneficial in the development of graphomotor skills among young learners.

Investigating fire NOx emissions with TROPOMI

<p>Most of the anthropogenic emissions of nitrogen oxides (NOx = NO<sub>2</sub> + NO) are linked to burning of fossil fuels for energy production, transportation or industrial processes. However, biomass burning and in particular large wild fires in tropical and sub-tropical regions can also be large sources of nitrogen oxides at least locally. Depending on the size of the fires, particles and gases can be lifted into the free troposphere and even higher, increasing the atmospheric lifetime of NOx and enabling long range transport.</p><p>The TROPOMI instrument on board of Sentinel 5 precursor (S5p) is a nadir viewing UV/vis imaging spectrometer launched in October 2017 and operationally providing data since July 2018. One of the main products that can be retrieved from TROPOMI spectra is tropospheric and total column NO<sub>2</sub>. Compared to previous UV/vis satellite instruments such as GOME, SCIAMACHY, GOME2 and OMI, TROPOMI has a higher spatial resolution of 3.5 x 5.5 km<sup>2</sup>. This reduced foot print size enables detection and evaluation of more localised sources such as individual fires and their plumes, and better separation of different contributions to the overall NO<sub>2</sub> loading.</p><p>In this presentation, IUP-Bremen TROPOMI NO<sub>2</sub> retrievals are evaluated for biomass burning signatures during the years 2018 to 2020, three years with very different burning seasons. The amounts and spatial distributions of NO<sub>2</sub> from fires are compared between the years and between different fire regions, and their impact on regions downwind of the sources is investigated.</p>

The effects of amblyopia on children’s reading performance after patching treatment

Purpose: The purpose of this study was to evaluate the effects of amblyopia on children’s reading performance after the successful patching treatment with 20/20 visual acuity (VA) in the treated eye. Methods: The treated amblyopes group included 10 children with strabismic amblyopia diagnosed on the first visit presenting VA equal or better than 0.0 logMAR (20/20 Snellen) in the better vision eye and VA worse than 0.2 logMAR (20/32 Snellen) in the worse eye that underwent patching treatment of amblyopia reaching a final VA equal to 0.0 logMAR in the treated eye. The control group comprised 10 children matched by age, gender and school-grade with no visual disorders. Reading performance was evaluated according to reading acuity (RA), critical print size (CPS), reading speed (RS) at 0.7 logMAR, and maximum reading speed (MRS) using the MNREAD chart. Results: Binocular reading performance was compared between groups and no statistically significant differences were found on RA, CPS, RS, or MRS ( p > 0.05). When analyzing monocular reading performances of treated amblyopes, a worse RA ( p = 0.04) and CPS ( p = 0.04) were observed on the previously amblyopic eye when compared to the fellow eye. When comparing the fellow eye from treated amblyopes and a randomly selected eye from controls, no statistically significant differences on RA, CPS, RS, or MRS were found ( p > 0.05). Conclusions: The results suggest that even patients who reached 20/20 VA in the treated eye after patching treatment for amblyopia may present persistent impaired reading performance. These findings reinforce the importance of reading performance testing as a tool when evaluating the visual function development in amblyopic patients.

Reconciling print-size and display-size constraints on reading

Two fundamental constraints limit the number of characters in text that can be displayed at one time—print size and display size. These dual constraints conflict in two important situations—when people with normal vision read text on small digital displays, and when people with low vision read magnified text. Here, we describe a unified framework for evaluating the joint impact of these constraints on reading performance. We measured reading speed as a function of print size for three digital formats (laptop, tablet, and cellphone) for 30 normally sighted and 10 low-vision participants. Our results showed that a minimum number of characters per line is required to achieve a criterion of 80% of maximum reading speed: 13 characters for normally sighted and eight characters for low-vision readers. This critical number of characters is nearly constant across font and display format. Possible reasons for this required number of characters are discussed. Combining these character count constraints with the requirements for adequate print size reveals that an individual’s use of a small digital display or the need for magnified print can shrink or entirely eliminate the range of print size necessary for achieving maximum reading speed.

What can we learn from TROPOMI observations of biomass burning NO2?

<p>Most of the anthropogenic emissions of nitrogen oxides (NOx = NO<sub>2</sub> + NO) are linked to burning of fossil fuels for energy production, transportation or industrial processes. However, biomass burning and in particular large wild fires in tropical and sub-tropical regions can also be important sources of nitrogen oxides, at least locally. Depending on the size of the fires, particles and gases are lifted into the free troposphere and even higher, increasing the atmospheric lifetime of NOx in these plumes and enabling long range transport.</p><p>The TROPOMI instrument on board of Sentinel 5 precursor (S5p) is a nadir viewing UV/vis imaging spectrometer launched in October 2017 and operationally providing data since July 2018. One of the main products that can be retrieved from TROPOMI spectra is tropospheric and total column NO<sub>2</sub>. Compared to previous UV/vis satellite instruments such as GOME, SCIAMACHY, GOME2 and OMI, TROPOMI has a higher spatial resolution of 3.5 x 5.5 km<sup>2</sup>. This reduced foot print size enables detection and evaluation of more localised sources such as individual fires and their plumes, and better separation of different contributions to the overall NO<sub>2</sub> loading.</p><p>In this presentation, IUP-Bremen TROPOMI NO<sub>2</sub> retrievals are evaluated for biomass burning signatures during 2018 and 2019, two years with very different burning seasons. The amounts and spatial distributions of NO<sub>2</sub> from fires are compared between the two years and between different fire regions, and their impact on regions downwind of the sources is investigated.</p>