Optimization of the Hemispherical Solar Distiller Performance Augmented by Different Basin Materials (steel, zinc, and copper) and Reflective Mirrors

The present comprehensive study aims to solve the problem of declining drinking water productivity from solar distillers. The hemispherical distillers are characterized by having the large condensing and receiving surface area, so the utilization of basin materials with high thermal conductivity and reflective mirrors are very effective to enhance a cumulative production of hemispherical distillation. To get the optimal basin materials with the reflective mirror that achieves the highest hemispherical distiller’s performance, three high thermal conductivity basin materials (steel, zinc, and copper) with reflective mirror were tested at the same conditions and compared to reference hemispherical unit. To realize this idea, four distillers was fabricated and tested at a same climate condition namely: Hemispherical solar Distiller with Black Silicone Walls (HSD-BSW), Hemispherical Solar Distiller with Steel Plate and Reflective Mirror (HSD-SPRM), Hemispherical Solar Distiller with Zinc Plate and Reflective Mirror (HSD-ZPRM), and Hemispherical Solar Distiller with Copper Plate and Reflective Mirror (HSD-CPRM). The experimental results presented that the utilization of copper basin materials and reflective mirror (HSD-CPRM) represents the good option to achieve the highest performance of hemispherical distiller, use the copper basin materials and reflective mirror (HSD-CPRM) gives a cumulative production reached 9500 mL/m2 day with improvement of 104.3% compared to reference hemispherical distiller (HSD-BSW). Also, use the copper basin materials and reflective mirror (HSD-CPRM) improves the daily thermal efficiency and exergy efficiency by 102.4% and 194.9%, respectively compared to HSD-BSW. The comprehensive economic analysis concluded that the use of copper basin materials and reflective mirrors (HSD-CPRM) reduced the distillate water cost per liter by 44.1% compared to HSD-BSW.

Reflective mirror-based line-scan adaptive optics OCT

Line-scan OCT, incorporated with adaptive optics (AO), offers high resolution, speed and sensitivity for imaging retinal structure and function in vivo. Here, we introduce its implementation with reflective mirror-based afocal telescopes, optimized for imaging light-induced retinal activity (optoretinography) and weak retinal reflections at the cellular scale. A non-planar optical design was followed based on previous recommendations with key differences specific to a line-scan geometry. The three beam paths fundamental to an OCT system -illumination/sample, detection, and reference - were modeled in Zemax optical design software to yield theoretically diffraction-limited performance over a 2.2 deg. field-of-view and 1.5 D vergence range at the eye's pupil. The performance for imaging retinal structure was exemplified by cellular-scale visualization of retinal ganglion cells, macrophages, foveal cones, and rods in human observers. The performance for functional imaging was exemplified by resolving the light-evoked optical changes in foveal cone photoreceptors where the spatial resolution was sufficient for cone spectral classification at an eccentricity 0.3 deg. from the foveal center. This enabled the first in vivo demonstration of reduced S-cone (short-wavelength cone) density in the human foveola, thus far observed only in ex vivo histological preparations. Together, the feasibility for high resolution imaging of retinal structure and function demonstrated here holds significant potential for basic science and translational applications.

Towards airborne laser Doppler vibrometry for structural health monitoring of large and curved structures

Laser Doppler vibrometry is an important sensing technology for many structural health monitoring (SHM) methods, such as modal analysis. However, when it comes to large civil structures, for example historic structures and bridges, the applicability of laser Doppler vibrometry is significantly constrained by inaccessible remote surfaces. Some of these surfaces are fully inaccessible to a ground-mounted laser Doppler vibrometer (LDV), while others are partially inaccessible, and measurements are only possible for low incident angles. Consequently, LDV measurements are either impossible or have a weak signal strength. In this study, the concept of constructing an airborne LDV for SHM is explored, including the examination of a recently developed mechanism, the partially airborne LDV, comprising a reflective mirror attached to a drone. Preliminary proof of concept laboratory tests have been successfully conducted using two different set-ups and drone models.

PRODUCTION OF ORNAMENTAL PYRAMID PEPPER WITH REFLECTIVE MATERIAL ON BENCHES IN DIFFERENT ENVIRONMENTS

Pepper trees have great ornamental value due to the varied colors of their fruits. Thus, the objective was to evaluate the Pyramid cultivar's production in different cultivation environments using benches with reflective material. The experiment was carried out in two protected environments: a) agricultural greenhouse with 42-50% shade screen under the plastic film and b) agricultural screen with black monofilament screen with 18% shade. Inside the environments, the production system was tested with and without reflective material on the cultivation bench. The experiments were conducted in a completely randomized design, with four replicates and six plants per plot. Joint analysis was used to compare environments. At 45, 60, and 75 days after transplantation, plant height, stem diameter, number of leaves, canopy area, and number of fruits were evaluated. The agricultural greenhouse with a 42/50% shade screen under the plastic film provided the formation of higher plants with greater stem diameter, greater number of leaves and fruits, and greater top diameter than the screen with 18% shading. The reflective mirror material showed positive results only for plant height.

REFLECTIVE MATERIALS AND SEEDS FROM DIFFERENT PLANT POSITIONS FOR PRODUCTION OF ACHACHAIRU SEEDLINGS

The plant environment in the production of Achachairu (Garcinia humilis) seedlings aims to obtain quality plants for orchards' formation. The present study aimed to evaluate reflective materials on benches and fruit seeds harvested from different plant positions to produce Achachairu seedlings. The reflective materials used under the cultivation benches were aluminum foil, "fake sequin" fabric, mirror, and tetra pak®. The fruit collection positions in the plants were at the top, median and bottom. The largest seedlings were obtained on the bench with reflective material of Tetra Pak®; however, in this material, there was a greater relationship between the height and diameter of the seedlings' neck, which is not desired for quality seedlings. The largest number of sheets was observed on the benches with reflective material of Tetra Pak® and "false sequin" fabric. The lowest dry masses of the root system and the lowest Dickson quality indexes were obtained from seedlings grown on the bench with reflective mirror material, forming lesser quality seedlings. The fruit collection place in the matrix plant did not influence the seedlings' quality. The use of reflective material on the bench is not recommended for the cultivation of Achachairu seedlings.

Optimization of Thickness Uniformity Distribution on a Large-Aperture Concave Reflective Mirror and Shadow Mask Design in a Planetary Rotation System

Improving the spatial resolution of remote sensing satellites has long been a challenge in the field of optical designing. Although the use of large-aperture reflective mirrors significantly improves the resolution of optical systems, controlling the film thickness uniformity remains an issue. The planetary rotation system (PRS) has received significant attention owing to the excellent uniformity of the coating applied to the large-aperture reflective mirror. However, the development of the PRS remains hindered by a lack of research on its properties and the design method of the shadow mask. To address this, we performed a theoretical analysis of the distribution of film thickness and uniformity in the PRS, which is impacted by parameters of geometric configuration in the vacuum chamber. We present a film thickness expression based on Knudsen’s law and the geometric configuration of the vacuum chamber that incorporates an additional shading function. Moreover, the variation of uniformity in the standard and counter PRSs was elucidated by changing the location of the evaporation source. Finally, a fixed-position shadow mask, which was obtained by theoretical design, allows the nonuniformity of the concave reflective mirror (with a 700 mm aperture) to reduce from 2.43% to 0.7%, highlighting the importance of initial shape design.