Time course chromatic adaptation under highly saturated illuminants

The goal of this study was to investigate the time course characteristics of chromatic adaptation under highly saturated illuminants. A psychophysical experiment with neutral matching method was conducted on a mobile display at different luminance levels. Models of chromatic adaptation degree against duration of time were fitted using a proportional rate growth function. The upper limit and growth rate of adaptation degree were studied. It was found that higher adapting luminance and lower display luminance led to higher degree and faster speed of chromatic adaptation. This study also proposed the time to achieve stable chromatic adaptation.

Material Properties of Discarded Textiles for Manufacturing Feedstocks

Presently, many textiles are discarded, in a condition that would allow a significant percentage of them to be able to be completely reused or recycled. Recent consumption practices embodied by “fast fashion”, fast purchasing, and fast disposal of out of style clothing has increased the volume of discarded clothing, as the repurposing and/or recycling of discarded textile materials has not increased at a proportional rate. Consequently, discarded clothing may have nearly no wear and tear or extensive use before consumers choose to dispose of these textiles. Increasing the recovery of textiles from municipal solid waste streams involves understanding the material properties that discarded textiles possess. Measuring the material properties available from discarded textiles will allow for understanding whether these textiles can be reused. At the same time as disposal of textiles has increased, geotextile purchase and use has been increasing rapidly. In the current study, tensile strength (break force) and permittivity of discarded clothing samples made of cotton, polyester, and cotton-polyester blends were measured and compared with material properties that are commonly specified for geotextile applications. Average break force values measured for discarded cotton and polyester and average permittivity values measured for 50%/50% cotton-polyester blends and polyester are higher than what is commonly recommended for common geotextile applications. Polyester materials showed promise for drainage and erosion control applications that would be commonly serviced by geotextiles, as polyester samples yielded average break force and permittivity values are above typically recommended geotextile minimum values for these applications.

Thermal and evaporative resistance measured in a vertically and a horizontally oriented air gap by Permetest skin model

This paper is a study of the correlation of the thermal resistance (Rct ) and the evaporative resistance (Ret ) in vertically and horizontally oriented air gaps by using the portable Permetest skin model. Experiments were done in a climatic chamber; an isothermal condition for Ret tests and non-isothermal condition for Rct tests. Foamed polyethylene air gap distance rings were prepared with a thickness of 2, 4 and 5 mm and their combinations to simulate the air gap distance from 0 to 16 mm which is more than the expected average gap in clothing systems. Test samples were woven fabric of 100 percent cotton, 100 percent polyester and their blends plus 100 percent of polypropylene, all have similar weight and structure. Results showed that with the increasing thickness of the air gap, Rct increased in a polynomial trend and Ret in a linear proportional rate up to 12 mm then started to change due to the effect of free convection and the different properties of materials. The surprising positive observation is that results from the horizontally and vertically oriented air gaps are very similar, and most of the results from the vertical air gap are slightly lower than the results from the horizontal air gap in all materials.

Response of grain sorghum to low rates of glufosinate and nicosulfuron

Previous research has shown that glufosinate and nicosulfuron at low rates can cause yield loss to grain sorghum. However, research has not been conducted to pinpoint the growth stage at which these herbicides are most injurious to grain sorghum. Therefore, field tests were conducted in 2016 and 2017 to determine the most sensitive growth stage for grain sorghum exposure to both glufosinate and nicosulfuron. Field test were designed with factor A being the herbicide applied (glufosinate or nicosulfuron). Factor B consisted of timing of herbicide application including V3, V8, flagleaf, heading, and soft dough stages. Factor C was glufosinate or nicosulfuron rate where a proportional rate of 656 g ai ha−1 of glufosinate and 35 g ai ha−1 of nicosulfuron was applied at 1/10×, 1/50×, and 1/250×. Visible injury, crop canopy heights (cm), and yield were reported as a percent of the nontreated. At the V3 growth stage visible injury of 32% from the 1/10× rate of glufosinate and 51% from the 1/10× rate of nicosulfuron was observed. This injury was reduced by 4 wk after application (WAA) and no yield loss occurred. Nicosulfuron was more injurious than glufosinate at a 1/10× and 1/50× rate when applied at the V8 and flagleaf growth stages resulting in death of the shoot, reduced heading, and yield. Yield losses from the 1/10× rate of nicosulfuron were observed from V8 through early heading and ranged from 41% to 96%. Yield losses from the 1/50× rate of nicosulfuron were 14% to 16% at the flagleaf and V8 growth stages respectively. The 1/10× rate of glufosinate caused 36% visible injury 2 WAA when applied at the flagleaf stage, which resulted in a 16% yield reduction. By 4 WAA visible injury from either herbicide at less than the 1/10× rate was not greater than 4%. Results indicate that injury can occur, but yield losses are more probable from low rates of nicosulfuron at V8 and flagleaf growth stages.

Comparison analysis of chattering in smooth sliding mode controlled DC-DC buck converter using constant plus proportional reaching law and proposed reaching laws

This paper presents a comparative analysis of chattering in sliding mode controlled DC-DC buck converter for chattering suppression using constant plus proportional reaching law and proposed reaching laws. A smooth SMC is used for chattering suppression in buck converter. The different switching functions are used in proposed reaching laws and constant plus proportional reaching law applied to SMC buck converter, the tan hyperbolic reaching law, sigmoid reaching law and constant plus proportional rate reaching law. The proposed method tan hyperbolic gives less switching loss among the reaching laws and stable output voltage. Inturn, performance of the buck converter increases, tanhyperbolic reaching law is more sensitive to matched, mismatched disturbance and parameter uncertainties. Loading conditions are also applied to the buck converter to measure the disturbances and parametric variations. The results are verified by MATLAB/Simulink.

The time course of chromatic adaptation under immersive illumination

Chromatic adaptation is a major contributory mechanism to constancy, yet its extent depends on many factors - spectral, spatial and temporal - which vary between studies and hence may contribute to differences in reported constancy indices. Here, we use the achromatic adjustment method to characterise the temporal progression of chromatic adaptation under a wide range of illuminations in an immersive environment. We control both the spectral properties of the illumination at the eye and the spatial context of the adjusted surface, to disentangle global adaptation from local contrast effects. We measure the timecourse of chromatic adaptation by assessing achromatic adjustments in 6 discrete time slots over 340 seconds. We find that the change over time of the adaptation state, proximally indicated by colour constancy indices (quantified by the relative closeness of the perceptual whitepoint to the test illumination chromaticity), (a) can be modelled by a proportional rate growth function, typically requiring more than 5 minutes to stabilise; (b) depends on the contrast between the test surface and its background, specifically increasing with decreasing test-background contrast; and (c) is generally similar in both extent and rate for different test illumination chromaticities. Adaptation progression does not differ significantly between illuminations on or off the daylight locus. Our results highlight the importance of considering exposure duration and stimulus configuration, as well as the distance between the pre-adaptation (reference) and test illumination chromaticities, when using achromatic adjustment as a measure of colour constancy.