Reflection Of Sunlight Research Articles

A Scalable Hybrid Fiber and Its Textile with Pore and Wrinkle Structures for Passive Personal Cooling

AbstractA radiative cooling garment is proposed as a promising strategy for ordinary people to attain high thermal comfort indoors and outdoors. However, low production and poor cooling capability restrict its wide applications. Herein, a high‐performance fiber and its textile with pore and wrinkle structures are fabricated that consist of polyethylene (PE) and polyethylene oxide. This specific structure endows the fiber and textile with high IR absorbance/emissivity (90.97%) and sunlight reflectance (93.77%). Therefore, the hybrid porous PE fiber and textile show good cooling capabilities and avoid the human body overheating by 6.8 °C under direct solar irradiation. The inner temperature of the transparent house with a roof covered by the textile decreases by 20.3 and 12.5 °C compared to the states of no extra cover and cotton cover, respectively. Apart from that, the results of the simulating and real human body measurements demonstrate that the porous PE textile enables the human body to acquire the same thermal comfort as the bare state. More importantly, the porous PE fiber and textile are superlight, flexible, moisture‐permeable, and waterproof, and meanwhile, have excellent tensile strength and UV protection properties. The good comprehensive performance indicates that the textile is appealing for fabricating summer clothes.

Outdoor Target Positioning Using Wii Remote IR Camera and Signal Modulation.

This paper investigates the use of the Wii remote IR (infrared) camera for outdoor target positioning. The Wii remote IR camera is widely used in various applications because of its capability of detection of up to four IR light sources with a fast frame rate (100 Hz) and a relatively low price. However, previous applications are limited to indoor uses due to the obvious reason of sunlight interference for outdoor applications. In this paper, a signal modulation technique is introduced, which enables the IR camera to look for a particular pattern encoded in an IR beacon. In this way, the IR camera can distinguish the IR beacon from the sunlight interference. The irradiance of the sunlight reflection is also analyzed to guarantee that the IR camera can detect the IR beacon even under extremely sunny weather conditions. As the Wii remote IR camera sensor is overloaded under an extremely bright condition that blocks the camera to see any light sources, we propose the use of a filter to dim the camera. Experimental results for outdoor tests are provided to validate the proposed methods.

The practice of responsible research and innovation in “climate engineering”

AbstractSunlight reflection and carbon removal proposals for “climate engineering” (CE) confront governance challenges that many emerging technologies face: their futures are uncertain, and by the time one can discern their shape or impacts, vested interests may block regulation, and publics are often left out of decision‐making about them. In response to these challenges, “responsible research and innovation” (RRI) has emerged as a framework to critique and correct for technocratic governance of emerging technologies, and CE has emerged as a prime case of where it can be helpfully applied. However, a critical lens is rarely applied to RRI itself. In this review, we first survey how RRI thinking has already been applied to both carbon removal and sunlight reflection methods for climate intervention. We examine how RRI is employed in four types of activities: Assessment processes and reports, principles and protocols for research governance, critical mappings of research, and deliberative and futuring engagements. Drawing upon this review, we identify tensions in RRI practice, including whether RRI forms or informs choices, the positionalities of RRI practitioners, and ways in which RRI activities enable or disable particular climate interventions. Finally, we recommend that RRI should situate CE within the long arc of sociotechnical proposals for addressing climate change, more actively connect interrogations of the knowledge economy with reparative engagements, include local or actor‐specific contexts, design authoritative assessments grounded in RRI, and go beyond treating critique and engagement as “de facto” governance.This article is categorized under: Policy and Governance > Private Governance of Climate Change Social Status of Climate Change Knowledge > Climate Science and Decision Making

Assessment of building daylight systems considering sunscreens under real conditions of the sky

Introduction. Lighting engineering is a complex scientific field which requires the generalization of knowledge in visual comfort evaluation, design and architectural solutions as well as in other areas including the humanities. Global ecological problems and the drive for Sustainable Development require achieving maximum energy efficiency from architectural designers. The tasks of designing daylight systems under real sky conditions cannot be solved without considering the problems of insolation and sunscreens. Russian and foreign standards cover long-put questions about the need to improve the daylight calculation method considering additional light reflected from adjacent surfaces under the clear and partially cloudy skies. The objective of the study is analysis and improvement of the daylight system calculation method considering sunscreens under intermediate sky conditions. Materials and methods. The methods of searching and selecting relevant literature in international abstract databases with well-developed tools for thematic search as well as analytical methods are described. Results. A method for calculating daylight system considering sunscreens under the intermediate sky conditions is suggested. The analysis of the obtained formulae confirmed the proposed theory: under the influence of direct sunlight, reflection from adjacent surfaces significantly increases the daylight level in a room. Conclusions. Assessment of daylight in a room under the intermediate sky conditions should take into account a reflection of the direct sunlight. Correcting the problem under conditions of the CIE overcast sky model in the calculation is associated with the availability of a light climate database. This approach makes it possible to formulate the criteria for a dynamic daylight assessment. Combination of an artificial lighting system with an automatic control mode guarantees the requirements of indoor illuminance and energy saving.

Infrared radiative performance of urban trees: spatial distribution and interspecific comparison among ten species in the UK by in-situ spectroscopy

Understanding the ways in which tree species interact with solar radiation has previously focused on transmission and reflection of sunlight, typically by examining individual leaves. Here we used a tree crown spectroscopy measurement method to conduct in-situ tests on the radiative performance of ten commonly planted tree species in the UK. Tree crown transflectance (comprehensive effect of transmission and reflection) was examined to determine i), how radiative performance of individual trees varies spatially within a species, and ii), how infrared radiative performance differs between tree species. Our results show that tree crown transflectance depends on the combination of tree crown morphology, local foliage distribution (leaf density, gaps in crown foliage contour, concave or convex crown shapes), solar altitude and leaf size. Spatially, the strongest tree crown transflection was found primarily towards sky on the sunlit side of trees rather than towards the zenith, meaning that infrared transflection towards surrounding buildings and pedestrians is substantial. For all ten species, the tree crown transflectance in the frontal sunlit area was linearly correlated with solar altitude on sunny days. Hence, a solar altitude of 45° was chosen as the benchmark condition for comparing interspecific differences. Interspecific comparison indicated that interspecific differences in the infrared radiative performance levels were strongly dependent on leaf size when no obvious gaps or concave shapes were present within the tree crowns. Our findings provide insights for understanding radiative interactions between urban trees and surrounding built environment, as well as for tree species selection in urban heat stress mitigation.

Dynamic LED light versus static LED light for depressed inpatients: results from a randomized feasibility trial

BackgroundRetrospective studies conducted in psychiatric wards have indicated a shorter duration of stay for depressed inpatients in bright compared to dim daylight-exposed rooms, pointing to a possible antidepressant effect of daylight conditions. Dynamic LED lighting, aiming to mimic daylight conditions, are currently been installed in several hospitals, but their feasibility is poorly investigated.MethodsTo investigate the feasibility of these systems, we developed and installed a LED-lighting system in four rooms in a psychiatric inpatient ward. The system could function statically or dynamically regarding light intensity and colour temperature. The system consisted of (A) a large LED luminaire built into the window jamb mimicking sunlight reflections, (B) two LED light luminaires in the ceiling and (C) a LED reading luminaire. In the static mode, the systems provided constant light from A and B. In the dynamic mode, the system changed light intensity and colour temperature using A, B and C. Patients with unipolar or bipolar depression were randomised to dynamic or static LED lighting for 4 weeks, in addition to standard treatment. Primary outcome was the rate of patients discontinuing the trial due to discomfort from the lighting condition. Secondary outcomes were recruitment and dropout rates, visual comfort, depressive symptoms and suicidal ideation.ResultsNo participants discontinued due to discomfort from the LED lighting. Recruitment rate was 39.8%, dropout from treatment rates were 56.3% in the dynamic group and 33.3% in the static group. 78.1% in the dynamic group were satisfied with the lighting compared with 71.8% in the static group. Discomfort from the light (glare) was reported by 11.5% in the dynamic group compared to 5.1% in the static group. Endpoint suicidal scores were 16.8 (10.4) in the dynamic and 16.3 (14.9) in the static group. The lighting system was 100% functional. The light sensor system proved unstable.ConclusionDropout from treatment was high primarily due to early discharge and with a lack of endpoint assessments. The feasibility study has influenced an upcoming large-scale dynamic lighting efficacy trial where we will use a shorter study period of 3 weeks and with more emphasis on endpoint assessments. The lighting was well tolerated in both groups, but some found intensity too low in the evening. Thus, we will use higher intensity blue-enriched light in the morning and higher intensity amber (blue-depleted) light in the evening in the upcoming study. The light sensor system needs to be improvedTrial registrationClinicalTrials.gov: NCT03363529

Spectroscopic Analysis of Thermodynamic Changes in Shataputi Abhrak Bhasma at Various Stages of its Preparation

Introduction: The science of Rasashastra needs to be upgraded with the help of technological advances of today's world, which shall open up new avenues for drug processing, development, and therapeutics in Ayurveda. Bhasma Kalpana is a widely used pharmaceutical form that demands exploration in view of the thermodynamic changes occurring in a closed system during incinerations. Shataputi Abhrak Bhasma encompassing a wide range of Putas was selected for assessing the quantum mechanical changes due to repeated incinerations. Aims and objectives: To analyze the effect of preparatory procedures on molecular structure, particle size, elemental assay, effect of rise in temperature on mass, and the percentage reflectance and absorbance of sunlight of Shataputi Abhrak Bhasma. Materials and methods: Shataputi Abhrak Bhasma was prepared in accordance to reference from Rasa Jala Nidhi. Shodhan was done with Nirvap in Godugdha and Maran was done with hundred Gajaputas adopting Bhavana with Gomutra. Abhrak Bhasma samples of various stages of incineration were subjected to advanced analytical tests like X-ray diffraction (XRD), inductive coupled plasma-atomic electron spectroscopy (ICP–AES), field emission gun-scanning electron microscopy (FEG-SEM), transmission electron microscopy (TEM), thermogravimetric analysisdifferential thermal analysis (TGA-DTA), and ultraviolet-visible-infrared spectroscopy (UV-Vis-IR) at the Indian Institute of Technology-Bombay. Results and conclusion: Advanced spectroscopic analytical tests revealed significant changes with increase in incinerations like complete destruction of the original compound, formation of newer compounds, significant change in the percentage of original elements, particle size reduction to the nanometer scale, thermal decomposition and recrystallization, and decrease in reflectance of sunlight. Clinical significance: The number of incinerations of a Bhasma is directly related to its therapeutic potential. Understanding the physical and chemical changes occurring at the molecular level of the Bhasma during incinerations highlighted the significance attached with the process of Maran. The study helped standardize and update the knowledge regarding differently incinerated Abhrak Bhasma and also explore the therapeutic potential of Shataputi Abhrak Bhasma that is regarded as a Rasayan.

Taking advantage of the the textile influence to add the dimension of concrete to the works of the artist (Claude Monet )

The impressionist artists' works are famous for their new distinctive visual features which resulted in an artistic revolution in the fields of drawing, painting and colours effects. They depend greatly on colour and light effects in achieving the three dimension perspective, and the effect of the sunlight on things and objects and how does it give different impressions with the sunlight's reflection. The word impressionism is actually derived from the impression on elements of nature. This term is in fact used to describe the artists of the mid nineteenth century who have contributed greatly in changing the manner of drawing forms in an enlightened way (pulsing with light), as an attempt to focus on what the human eye sees in a glance, and not what the seer feels towards this natural scene. This school marks a turning point and an inspiration in the transitional period from classical arts to modern arts. which consequently aims at recording the impression as perceived by the eye and this is achieved through the reflection of light, climate, season and time.

With Covid-19: Attempt of learning to observe the moon using a telescope at home

AbstractStudents took an assembly-type telescope kit from a public elementary school and brought it to their homes in 2019. Three classes attempted to observe the Moon at home using the Kaifu-NAOJ Telescope Kit. As a result, all children observed the Moon at home using the kit. From their observations, around 90% identified the existence of craters and understood the reflection of sunlight on the Moon’s surface. As Covid-19 prevention measures in education, we propose the introduction of at-home telescopic observations for STEAM activities.

Airborne Measurements of Surface Wind and Slope Statistics over the Ocean

AbstractAs reported in 1954, more than a half century ago, C. Cox and W. Munk developed an empirical model of the slope distribution of ocean surface waves that has been widely used ever since to model the optical properties of the sea surface and is of particular importance to the satellite remote sensing community. In that work, the reflectance of sunlight was photographed from a Boeing B-17G bomber and was then analyzed. In this paper, surface slope statistics are investigated from airborne scanning topographic lidar data collected during a series of field experiments off the coast of California and in the Gulf of Mexico, over a broad range of environmental conditions, with wind speeds ranging from approximately 2 to 13 m s−1. Unlike the reflectance-based approach of Cox and Munk, the slope distribution is computed by counting laser glints produced by specular reflections as the lidar is scanned over the surface of the ocean. We find good agreement with their measurements for the mean-square slope and with more recent (2006) results from Bréon and Henriot that were based on satellite remote sensing. Significant discrepancies for the higher-order statistics are found and discussed. We also demonstrate here that airborne scanning lidar technology offers a viable means of remotely estimating surface wind speed and momentum flux.

Effect of storage on the quality of processed palm oil collected from local milling points within Ile-Ife, Osun State, Nigeria.

The influence of storage practices on physicochemical and microbial changes in crude palm oil (CPO) from milling points in Ile-Ife, Nigeria were investigated. Freshly milled CPO samples were collected from four traditional milling points, dispensed in 150mL portions in sterile bottles and stored under two different conditions (sunlight reflection and in the dark, both at room temperature) for 4months. Samples were obtained periodically during the storage period for microbiological and physicochemical analysis following established methods. The aerobic mesophilic (2.16 × 106cfu/mL) and Enteric bacterial (1.6 × 106cfu/mL) counts of the fresh CPO samples decreased during storage with those exposed to sunlight reflections having very high significant difference (P < 0.00) compared to those stored in the dark at P ≤ 0.05. The bacterial isolates were identified as Bacillus pasteurii (29%), Staphylococcus aureus (22%), Enterobacter aerogenes (17%), Micrococcus sp. (12%), Escherichia coli (8%), Pseudomonas aeruginosa (7%) and Serratia marcescens (5%). Of the physicochemical parameters studied, moisture content (MC) reduced significantly from between 2.55 and 5.50% in fresh sample to between 0.1 and 0.5% at the end of storage while the free fatty acids (FFA) increased from between 0.5 and 1.0% to between 2.2 and 3.1% respectively. Storage under the influence of sunlight resulted in significant increase in iodine value of CPO from Mills 1, 2 and 4, indicating oxidative instability of the palm oil. It could be concluded that storage of freshly milled palm oil at room temperature (in the dark or exposure to sunlight) for a period of 4months resulted in reduced bacterial load, decrease in MC and stable peroxide value and FFA.

Raspberry-Shaped Thermochromic Energy Storage Nanocapsule with Tunable Sunlight Absorption Based on Color Change for Temperature Regulation.

A novel raspberry-shaped thermochromic energy storage nanocapsule (RTESN) is successfully designed and fabricated with switchable sunlight absorption capacity based on color change for temperature regulation. The RTESN is developed by grafting amino-modified silica shell thermochromic nanoparticles (amino-TLD@SiO2 ) on the surface of epoxy-functionalized energy storage nanocapsules (paraffin@PSG), with a total particle size about 450 nm. RTESN exhibits a deep color under low temperatures, which can absorb sunlight for heating. During the continuous thermal energy supply, paraffin@PSG is capable of storing thermal energy owing to its large latent heat capacity of 118.7 J g-1 , thereby maintaining the slow temperature increase. When the temperature is higher than the phase change temperature of paraffin@PSG, the color of amino-TLD@SiO2 turns to white with more reflection of sunlight so that it reduces the absorption of thermal energy and prevents the further increase of temperature. The thermal regulation behavior is confirmed by setting up a wooden house with the surface covered with RTESN. Compared with the blank wooden house, the RTESN covered wooden house (RTESN-H) displays thermal insulation performances during heating and cooling with a maximum temperature difference of 7 °C.

A new lane following method based on deep learning for automated vehicles using surround view images

In this study, a lane following method based on deep learning from surround view images for autonomous driving of a ground vehicle is proposed. Previous methods can be suffered from false detection by hand-craft feature extraction in color-based binarization especially when the surround view images are exposed to unfavorable conditions such as strong shadow, sunlight reflections or shallow puddles on the roads. Thus the proposed method adopts a modified convolutional neural network structure to estimate the 6 coefficients of the left and right lane lines modeled by two quadratic functions from the surround view images of a vehicle. Then, a desired steering wheel angle is calculated using Stanley method to make a test vehicle follow a test lane autonomously by the proposed method. Autonomous driving experiment of the test vehicle using the proposed method was carried out on the test lane with various unfavorable conditions high-curvature lane of a test field. Experiment results showed that the vehicle was self-driven autonomously and stably without any lane departures on the test lane.

Deep Space Observations of Sun Glints from Marine Ice Clouds

The Earth Polychromatic Camera (EPIC) onboard the Deep Space Climate Observatory (DSCOVR) spacecraft takes images of the sunlit face of the earth from a million miles away. Earlier work showed that EPIC detected the specular reflection of sunlight (i.e., sun glint) from ice crystals floating in cold clouds over land; here we show that this phenomenon can also be detected over oceans. Furthermore, the results show that—using its observations at oxygen A-band absorption bands—EPIC can distinguish glints off marine ice clouds from those off the ocean surface. The analysis of more than two years of EPIC data reveals that the two kinds of glints are detected with comparable frequency. Glints off clouds are shown to be generally brighter but smaller in spatial extent. It is also demonstrated that glints off ice clouds have a discernible effect on the regional mean reflectance and that EPIC observations can help constrain the radiative contribution of oriented ice crystals.

There is no Plan B for dealing with the climate crisis

ABSTRACTTo halt global warming, the emission of carbon dioxide into the atmosphere by human activities such as fossil fuel burning, cement production, and deforestation needs to be brought all the way to zero. The longer it takes to do so, the hotter the world will get. Lack of progress towards decarbonization has created justifiable panic about the climate crisis. This has led to an intensified interest in technological climate interventions that involve increasing the reflection of sunlight to space by injecting substances into the stratosphere which lead to the formation of highly reflective particles. When first suggested, such albedo modification schemes were introduced as a “Plan B,” in case the world economy fails to decarbonize, and this scenario has dominated much of the public perception of albedo modification as a savior waiting in the wings to protect the world against massive climate change arising from a failure to decarbonize.But because of the mismatch between the millennial persistence time of carbon dioxide and the sub-decadal persistence of stratospheric particles, albedo modification can never safely play more than a very minor role in the portfolio of solutions. There is simply no substitute for decarbonization.

Dispensing Technology of 3D Printing Optical Lens with Its Applications

Current 3D printed lens technology faces reduced efficiency due to stepped and stacked lens surfaces. This research employs a faster jet dispensing method which reduces these issues. It uses UV-curable material and merges droplets before they are cured to obtain very smooth lens surfaces without any post-processing and without manufacturing a mold for lens structures. This technology can be applied to lens manufacturing in a variety of products, especially in the form of arrays, saving development time and reducing cost. Two experiments of LED (Light-emitting diode) lens and solar cell lens array mask implementations are presented to demonstrate the power of the method. Furthermore, this study analyzes the effect of different contact angles created by jet dispensing technology, including a detailed exploration of fluid viscosity and tooling heating parameters. Our results show that the LED lens can be manufactured to increase the luminous flux of large angles. Furthermore, the lens array mask for solar cells can be manufactured to reduce sunlight reflection and increase secondary refraction, which enables solar cells to achieve higher photoelectric conversion efficiency and to increase their power generation up to 4.82%.

The Negative Impact of Solar Reflections Caused by Reflective Buildings’ Facades: Case Study of the Nasher Museum in Texas

Large reflective facades in buildings can cause severe visual discomfort due to the reflection of sunlight falling on buildings’ surfaces. These intense reflections can cause a intolerable glare and contribute to overheating the interior of surrounding buildings. An example of reflective building materials causing glare is experienced in Dallas, Texas, where a residential tower, which was fitted with a fully glazed façade, has caused intense specular reflections into the Nasher sculpture museum. The problem has caused glare and overheating of the interior spaces in the museum, thus leading to the damage and deterioration of the sculptures on display.In order to examine the negative impact of the Museum Tower’s reflective façade on the visual comfort inside the Nasher museum, glare simulations are carried out at different times of the year. Additionally, to examine a possible solution to the glare problem, a proposed solution of using a less reflective material on the tower’s facade is examined via glare simulations. The initial set of simulations confirmed that tower skin contributed to blinding glare particularly at 12:00 and 15:00 on the summer and winter solstice, and the spring equinox. Use of less reflective material on the tower façade concluded that the tower façade still contributed to glare and that is due to its convex geometry.

Approach to fabricating high-performance cooler with near-ideal emissive spectrum for above-ambient air temperature radiative cooling

Radiative cooling is a passive cooling method that can radiate heat into the universe through transparent atmospheric windows. A good radiative cooler should possess not only a suitable emissive spectrum profile but also characteristics such as flexibility, large-area, low-cost, and angle-independency. To satisfy these demands, we propose an approach to fabricate a photonic crystal-structured UV-curable adhesive (PCSUVA) on a polyethylene terephthalate (PET) substrate using UV nanoimprint lithography. The PCSUVA-based radiative cooler has a near-ideal emissive spectrum in the wavelength range of 0.4–25 μm and the cooler is successful in cooling its object, no matter the object needs sunlight or not. When the PCSUVA is coated on a transparent substrate (i.e. PET), it can reduce the temperature of the underlying silicon wafer by 1.2 ± 0.2 °C, and when the PCSUVA is coated on PET backed with an Ag layer, it can reduce the temperature of the underlying silicon wafer by 7.7 ± 0.2 °C on a summer day. The achieved cooling effect can be attributed to the reflection of sunlight by the Ag layer and the thermal emission of the PCSUVA. The approach is cost-effective, making it a suitable candidate for a flexible, large-area, low-cost, and angle-independent radiative cooler.

Hyperspectral analysis of objects under shadow conditions based on field reflectance measurements.

Shaded objects in remote sensing data are usually neglected because of their low reflectance. The common treatment for detecting shadows consists of simple identification and straightforward removal; however, this approach is often criticized owing to the complexity and difficulty of its application and the incompleteness of the treated data. Recent efforts with hyperspectral field reflectance measurements have provided alternatives to scrutinize the issues of shadows. To demonstrate our proposed framework, we first gathered basic hyperspectral data with a spectrometer at Peking University, Beijing, China. Subsequently, we classified the spectral reflectances into three types: sunlight reflectance, shadow reflectance, and simulated reflectance. The spectral characteristics of shadows can provide pertinent classification information despite their low reflectance. Under full shadow conditions, the simulated reflectance was close to the sunlight reflectance because the same reduction ratio was used for the spectralon panel during the measurement process. In addition, the ratio of the shadow reflectance to the sunlight reflectance seemed to be related to the characteristics of the obstruction. The findings in this paper can contribute to a comprehensive understanding of the influence of shadows in remote sensing research, demonstrating the potential of fully utilizing typically neglected shadow information.

Lighting Environment Optimization of Highway Tunnel Entrance Based on Simulation Research

At the entrance of a tunnel, reflection of sunlight from the surrounding environment and a lack of adequate lighting usually cause some vision problems. The purpose of this study is to optimize the lighting environment at the entrance of highway tunnels. Firstly, based on a highway tunnel in Zhejiang Province, the natural illumination intensity in different seasons and climate conditions inside and outside the tunnel entrance was analyzed by means of DIALux simulation software. Then the variation in illumination conditions with distance at the entrance of the tunnel was analyzed. Finally, based on the results above, this study proposes four solutions as follows: setting up a shading shed, auxiliary lighting facilities, decelerating reflective markings, and an adaptive dimming system.