Effect of Basil Seed and Xanthan Gums Coating on Colour and Surface Change Kinetics of Peach Slices During Infrared Drying

The article presented conducts the research of infrared radiation power effect on the colour and surface changes of peach slices coated with basil seeds gum (BSG) and xanthan gum during drying. The colour indices include redness (a*), yellowness (b*), lightness (L*), and total colour difference (∆E), which were used for the purposes of colour change calculation. As the IR radiation power increased from 150 W to 375 W, the average values of L*, a* and b* of uncoated and coated peach slices decreased from 67.45 to 65.41; 7.95 to 5.89; and 49.21 to 38.52, respectively. The lowest ∆E and surface change values were observed in peach samples coated with BSG. The modelling results showed that the MMF model was the best model to describe the total colour difference of uncoated and coated peach slices (the average correlation coefficient was equal to 0.991 and the average standard error was equal to 1.791). The surface area change (%) of uncoated and coated peach slices increased with the progression of drying time, but the rate of changes was lower for the coated peach slices with BSG. The current research indicated that BSG coating has the potential to improve surface colour and appearance quality of dried peach slices.

Three competitors in three dimensions: photogrammetry reveals rapid overgrowth of coral during multispecies competition with sponges and algae

Competition for limited space is an important driver of benthic community structure on coral reefs. Studies of coral-algae and coral-sponge interactions often show competitive dominance of algae and sponges over corals, but little is known about the outcomes when these groups compete in a multispecies context. Multispecies competition is increasingly common on Caribbean coral reefs as environmental degradation drives loss of reef-building corals and proliferation of alternative organisms such as algae and sponges. New methods are needed to understand multispecies competition, whose outcomes can differ widely from pairwise competition and range from coexistence to exclusion. In this study, we used 3D photogrammetry and image analyses to compare pairwise and multispecies competition on reefs in the US Virgin Islands. Sponges (Desmapsamma anchorata, Aplysina cauliformis) and macroalgae (Lobophora variegata) were attached to coral (Porites astreoides) and arranged to simulate multispecies (coral-sponge-algae) and pairwise (coral-sponge, coral-algae) competition. Photogrammetric 3D models were produced to measure surface area change of coral and sponges, and photographs were analyzed to measure sponge-coral, algae-coral, and algae-sponge overgrowth. Coral lost more surface area and was overgrown more rapidly by the sponge D. anchorata in multispecies treatments, when the sponge was also in contact with algae. Algae contact may confer a competitive advantage to the sponge D. anchorata, but not to A. cauliformis, underscoring the species-specificity of these interactions. This first application of photogrammetry to study competition showed meaningful losses of living coral that, combined with significant overgrowths by competitors detected from image analyses, exposed a novel outcome of multispecies competition.

Time Series Remote Sensing Data-Based Identification of the Dominant Factor for Inland Lake Surface Area Change: Anthropogenic Activities or Natural Events?

Inland lake variations are considered sensitive indicators of global climate change. However, human activity is playing as a more and more important role in inland lake area variations. Therefore, it is critical to identify whether anthropogenic activity or natural events is the dominant factor in inland lake surface area change. In this study, we proposed a method that combines the Douglas-Peucker simplification algorithm and the bend simplification algorithm to locate major lake surface area disturbances. These disturbances were used to extract the features that been used to classify disturbances into anthropogenic or natural. We took the nine lakes in Yunnan Province as test sites, a 31-year long (from 1987 to 2017) time series Landsat TM/OLI images and HJ-1A/1B used as data sources, the official records were used as references to aid the feature extraction and disturbance identification accuracy assessment. Results of our method for disturbance location and disturbance identification could be concluded as follows: (1) The method can accurately locate the main lake changing events based on the time series lake surface area curve. The accuracy of this model for segmenting the time series of lake surface area in our study area was 94.73%. (2) Our proposed method achieved an overall accuracy of 87.75%, with an F-score of 85.71 for anthropogenic disturbances and an F-score of 88.89 for natural disturbances. (3) According to our results, lakes in Yunnan Province of China have undergone intensive disturbances. Human-induced disturbances occurred almost twice as much as natural disturbances, indicating intensified disturbances caused by human activities. This inland lake area disturbance identification method is expected to uncover whether a disturbance to inland lake area is human activity-induced or a natural event, and to monitor whether disturbances of lake surface area are intensified for a region.

Time Series Remote Sensing Data-Based Identification of the Dominant Factor for Inland Lake Surface Area Change: Anthropogenic Activities or Natural Events?

Inland lake variations are considered sensitive indicators of global climate change. However, human activity is playing as a more and more important role in inland lake area variations. Therefore, it is critical to identify whether anthropogenic activity or natural event is playing as the dominant factor in inland lake surface area change. In this study, we proposed a Douglas-Peucker simplification algorithm and bend simplification algorithm combined method to locate major lake surface area disturbances; these disturbances were then characterized to extract the time series change features according to documented records; and the disturbances were finally classified into anthropogenic or natural. We took the nine lakes in Yunnan Province as test sites, a 31 years long (from 1987 to 2017) time series Landsat TM/OLI images and HJ-1A/1B used as data sources, the official records was used as references to aid the feature extraction and disturbance identification accuracy. Results of our method for both disturbance location and the disturbance identification could be concluded as follows: 1) The method can accurately locate the main lake changing events based on the time series lake surface area curve. The accuracy of this model for segmenting the lake area time series curves in our study area was 95.24%. 2) Our proposed method achieved an overall accuracy of 91.67%, with F-score of 94.67 for anthropogenic disturbances and F-score of 85.71 for natural disturbances. 3) According to our results, lakes in Yunnan Provence, China, have undergone extensive disturbances, and the human-induced disturbances occurred almost twice as often as natural disturbances, indicating intensified disturbances caused by human activities. This inland lake area disturbance identification method is expected to uncover whether a disturbance to inland lake area is human activity-induced or natural event.

Enhanced Evaporation of Microscale Droplets With an Infrared Laser

Enhancement of water droplet evaporation by added infrared radiation was modeled and studied experimentally in a vertical laminar flow channel. Experiments were conducted on droplets with nominal initial diameters of 50 μm in air with relative humidities ranging from 0% to 90% RH. A 2800 nm laser was used with radiant flux densities as high as 4 × 105 W/m2. Droplet size as a function of time was measured by a shadowgraph technique. The model assumed quasi-steady behavior, a low Biot number liquid phase, and constant gas–vapor phase material properties, while the experimental results were required for model validation and calibration. For radiant flux densities less than 104 W/m2, droplet evaporation rates remained essentially constant over their full evaporation, but at rates up to 10% higher than for the no radiation case. At higher radiant flux density, the surface-area change with time became progressively more nonlinear, indicating that the radiation had diminished effects on evaporation as the size of the droplets decreased. The drying time for a 50 μm water droplet was an order of magnitude faster when comparing the 106 W/m2 case to the no radiation case. The model was used to estimate the droplet temperature. Between 104 and 5 × 105 W/m2, the droplet temperature changed from being below to above the environment temperature. Thus, the direction of conduction between the droplet and the environment also changed. The proposed model was able to predict the changing evaporation rates for droplets exposed to radiation for ambient conditions varying from dry air to 90% relative humidity.

Glacier change in the Cariboo Mountains, British Columbia, Canada (1952–2005)

We applied photogrammetric methods with aerial photography from 11 different years between 1946 and 2005 to assess changes in area and volume of 33 glaciers in the Cariboo Mountains of British Columbia for the latter half of the 20th century. These are used to identify changes in extent and elevation primarily for the periods 1952–1985, 1985–2005, and 1952–2005. All glaciers receded during the period 1952–2005; area retreat averaged −0.19 ± 0.05 % a−1. From 1952 to 1985, nine glaciers advanced; following 1985, retreat rates accelerated to −0.41 ± 0.12% a−1. Thinning rates of a subset of seven glaciers likewise accelerated, from −0.14 ± 0.04 m w.e. a−1 (1952–1985) to −0.50 ± 0.07 m w.e. a−1 for the period 1985–2005. Temperatures increased from the earlier to the latter period for the ablation (+0.38 °C) and accumulation (+0.87 °C) seasons, and average precipitation decreased, particularly in the accumulation season (−32 mm, −3.2%). Our comparison of surface area change with glacier morphometry corroborates previous studies that show primary relations between extent change and surface area. We also find that the strength and sign of these relations varied for different epochs. Our results also indicate that the 1985 glacier extent for the study area reported previously by other studies may be slightly overestimated due to errant mapping of late-lying snow cover.

Satellite observations show no net change in the percentage of supraglacial debris-covered area in northern Pakistan from 1977 to 2014

Spatial evolution of supraglacial debris cover on mountain glaciers is a largely unmonitored and poorly understood phenomenon that directly affects glacier melt. Supraglacial debris cover for 93 glaciers in the Karakoram, northern Pakistan, was mapped from Landsat imagery acquired in 1977, 1998, 2009 and 2014. Surge-type glaciers occupy 41% of the study area and were considered separately. The time series of debris-covered surface area change shows a mean value of zero or near-zero change for both surging and non-surging glaciers. An increase in debris-covered area is often associated with negative regional mass balances. We extend this logic to suggest that the stable regional mass balances in the Karakoram explain the zero or near-zero change in debris-covered area. This coupling of trends combined with our 37 year time series of data suggests the Karakoram anomaly extends further back in time than previously known.