Changes In Reflectance Research Articles

Inertinite Reflectance in Relation to Combustion Temperature

Inertinite, a product of wildfire, holds important information on global temperature change. The relationship between its reflectance and temperature has been widely used to identify wildfire events in paleo-sedimentary environments, but the currently used equations relating inertinite reflectance and combustion temperature are subject to large errors. Therefore, to clarify the relationship between inertinite reflectance and combustion temperature further, we systematically analyzed changes in inertinite reflectance under different combustion durations based on the literature’s data. Results confirmed that inertinite reflectance is related to combustion duration. Disregarding combustion duration, the combustion equation is T=267.52+110.19×RoR2=0.91, where T is the combustion temperature, Ro% is the measured inertinite reflectance, and R2 is the correlation coefficient. Under a combustion duration of 1 h, the equation is T=273.57+113.89×RoR2=0.91, and under a combustion duration longer than 5 h (including 5 h), the equation is T=232.91+110.6×RoR2=0.94. These three equations not only account for the temporal factor, but are also more precise than the commonly used formula. This study provides a scientific basis for research on paleo-wildfire.

Using contrasts in horizontal P-wave reflectivity to map the base of the continental lithosphere: Results for the central and eastern U.S.

Vertical-incidence seismic reflection profiles generated from global phases for 16 earthquakes recorded by stations of the Transportable Array (TA) show distinctive patterns of P-wave reflectivity in the uppermost mantle beneath the central and eastern United States. The overall distribution of reflections identified objectively using the sign test statistic applied to bootstrapped stacks is consistent with a westward increase in depth of the lithosphere-asthenosphere boundary (LAB) from roughly 110 to 250 km that is marked within the lower lithosphere by piecewise continuous segments of elevated horizontal P-wave reflectivity. For some profiles, the onsets of zones of increased reflectivity closely match depths corresponding to the maximum negative S-wave velocity gradients found by surface-wave tomography, suggesting that P-wave reflectivity can be used to help characterize properties of the lower lithosphere. We suggest that the vertical change in horizontal reflectivity straddles the lithosphere-asthenosphere transition, encompassing a broad zone of layering caused by increased strain in the lower lithosphere as well as drag-induced flow in the asthenosphere. Some of the lines also show waveforms that fall within the depth range of arrivals identified as midlithospheric discontinuities (MLDs) in overlapping Sp receiver-function profiles. The reflection waveforms observed in the TA lines are mostly multicyclic with a mix of polarities indicating a layered transition, consistent with previous observations and model studies that show the breakup of single Sp waveforms into a series of less prominent, shorter-period P-wave reflections as the dominant frequency of incident energy is increased.

Rapid-response, low-detection-limit, positive-negative air pressure sensing: GaN chips integrated with hydrophobic PDMS films

Despite the importance of positive and negative pressure sensing in numerous domains, the availability of a single sensing unit adept at handling this dual task remains highly limited. This study introduces a compact optical device capable of swiftly and precisely detecting positive and negative pressures ranging from −35 kPa to 35 kPa. The GaN chip, which serves as a core component of the device, is monolithically integrated with light-emitting and light-detecting elements. By combining a deformable PDMS film coated with a hydrophobic layer, the chip can respond to changes in optical reflectance induced by pressure fluctuations. The integrated sensing device has low detection limits of 4.3 Pa and −7.8 Pa and fast response times of 0.14 s and 0.22 s for positive and negative pressure variations, respectively. The device also demonstrates adaptability in capturing distinct human breathing patterns. The proposed device, characterized by its compactness, responsiveness, and ease of operation, holds promise for a variety of pressure-sensing applications.

Simultaneous monitoring of humidity and temperature by polarization volume gratings utilizing responsive cholesteric liquid crystals

Optical sensing devices are utilized for noncontact operation in harsh environments due to their advantage of local separation between the measurement and detector systems. Cholesteric liquid crystals (CLCs) with vivid structural colors are integrated into optical sensors, attracting significant interest for naked-eye detection. To enable vision-based, real-time remote monitoring, we propose a cost-effective method to convert the stimuli-responsive reflection change of CLCs into recordable diffraction patterns using polarization volume gratings (PVGs). This enables real-time remote readout of environmental parameters. PVGs are constructed through holographic polarization interference and photoalignment technologies. The diffraction efficiency of PVGs varies with relative humidity (RH). To improve sensing accuracy and extend the monitoring range of RH, we employ two methods: an orthogonal grating structure and dual-wavelength detection optical path. In addition, we demonstrate the simultaneous measurement of humidity and temperature by cascading independently responding PVGs. We believe that this work will provide a broader perspective and expand the application of light dimensions in LC-based optical sensing.

Efficacy and safety of azelastine hydrochloride and fluticasone propionate nasal spray in treating allergic rhinitis: a randomized controlled trial

Background: MP-AzeFlu (Dymista; Meda Pharma GmbH & Co., KG), a formulation combining azelastine hydrochloride and fluticasone propionate in a single spray, is superior to fluticasone propionate alone in relieving symptoms and improving the quality of life of patients with allergic rhinitis. Objectives: In this study, we evaluated whether the effect of AzeFlu, a generic drug manufactured from China, is equivalent to that of MP-AzeFlu. Methods: In total, 679 patients were recruited for a multicentre, randomized, double-blind, original drug-controlled, and parallel-group clinical trial. Overall, 339 and 340 patients were administered with AzeFlu and MP-AzeFlu, respectively. Efficacy was assessed by changes in the reflective total nasal symptom score, the area under the curve of reflective total nasal symptom score changes over time, changes from baseline in individual nasal symptom scores, and the Rhinoconjunctivitis Quality of Life Questionnaire. In addition, a safety evaluation was simultaneously performed. Results: AzeFlu and MP-AzeFlu reduced the reflective total nasal symptom score from baseline (AzeFlu −6.7 [standard deviation, 2.59]; MP-AzeFlu −6.7 [standard deviation, 2.76]; P = 0.905) and improved nasal symptoms and quality of life (AzeFlu −62.3 [standard deviation, 33.59]; MP-AzeFlu −64.7 [standard deviation, 33.73]; P = 0.394) in patients with allergic rhinitis. Significant differences were not observed between groups. Conclusion: AzeFlu showed effects equivalent to those of MP-AzeFlu in this clinical trial and may benefit Chinese patients with allergic rhinitis. Registration number: CTR20190189 (chinadrugtrials.org.cn/index.html)

Health literacy & somatic education: a salutogenic self-resource critical health intervention

Abstract Issue Non-communicable diseases (NCDs), such as musculoskeletal conditions, cause severe functional limitations. Therapeutic practices in this field have employed a theoretical-practical framework with a pathogenic and mechanistic bias. However, the causes of these NCD’s are also related to biopsychosocial factors. Therefore, a critical theoretical-practical approach, such as Somatic Education, becomes relevant as it introduces a subjective experience to an educational praxis, modifying the meaning processes in human movement experience in a complimentary approach to the pathogenic perspective. Description of the problem There is a perceptual poverty in movement experience, which dissociates doing from feeling. Somatic practices aim to foster movement awareness (perception) and autonomy (self-regulation), placing the individual as a valuable resource, strengthening the capacity for understanding, reflection and habitus change. This presentation will focus on the following research questions: Can Somatic Education, as a critical intervention of the body, contribute to increased levels of health literacy? Can somatic practices contribute to sustainable health development? Is it possible to create a new meaningful process in human movement experience through this practice incrementing its salutogenic emphasis? Results/Effects Somatic practices foster integrative approaches of health, promoting subjective bodily experience (interface between doing, thinking and feeling). Integrative progress can urge the embodiment of health literacy, encouraging more active and awareness of individuals related to their well-being, contributing to sustainable health development. Moreover, subjective bodily experience transforms the process of meaning in movement experience. Lessons Somatic practices enhance NCDs prevention and education, increasing health literacy rates through innovative conceptual foundations.

Hyperspectral Imaging Reveals Differential Carotenoid and Chlorophyll Temporal Dynamics and Spatial Patterns in Scots Pine Under Water Stress.

Drought-related die-off events have been observed throughout Europe in Scots pine (Pinus sylvestris L.). Such events are exacerbated by carbon starvation that is, an imbalance of photosynthetic productivity and resource usage. Recent evidence suggests that optically measurable photosynthetic pigments such as chlorophylls and carotenoids respond to water stress (WS). However, there is a lack of measurements using imaging spectroscopy, and the mechanisms linking xanthophyll-related changes in reflectance captured by the photochemical reflectance index (PRI) and chlorophyll changes in red edge position (REP) to WS are not understood. To probe this, we conducted a greenhouse experiment where 3-year-old Pinus sylvestris saplings were subjected to water limitation and followed using hyperspectral imaging (HSI) spectroscopy, water status and photosynthetic measurements. Carotenoids (e.g., xanthophyll cycle) and chlorophylls responded to WS, which was observed using the HSI-derived indices PRI and REP respectively. The spatial-temporal response in these two pigment-reflectance groupings differed. The spatial distribution of PRI represented the light intensity around the time of the measurement, whereas REP reflected the daily averaged light intensity over the experimental course. A further difference was noted upon rewatering, where the carotenoid-related PRI partially recovered but the chlorophyll-related REP did not.

HAMSTER: Hyperspectral Albedo Maps dataset with high Spatial and TEmporal Resolution

Abstract. Surface albedo is an important parameter in radiative-transfer simulations of the Earth's system as it is fundamental for correctly calculating the energy budget of the planet. The Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on NASA's Terra and Aqua satellites continuously monitor daily and yearly changes in reflection at the planetary surface. The MODIS Surface Reflectance Black-Sky Albedo dataset (version 6.1 of MCD43D) provides detailed albedo maps for seven spectral bands in the visible and near-infrared range. These albedo maps allow us to classify different Lambertian surface types and their seasonal and yearly variability and change, albeit only into seven spectral bands. However, a complete set of albedo maps covering the entire wavelength range is required to simulate radiance spectra and correctly retrieve atmospheric and cloud properties from remote sensing observations of the Earth. We use a principal component analysis (PCA) regression algorithm to generate hyperspectral albedo maps of the Earth. By combining different datasets containing laboratory measurements of hyperspectral reflectance for various dry soils, vegetation surfaces, and mixtures of both, we reconstruct albedo maps across the entire wavelength range from 400 to 2500 nm. The PCA method is trained with a 10-year average of MODIS data for each day of the year. We obtain hyperspectral albedo maps with a spatial resolution of 0.05° in latitude and longitude, a spectral resolution of 10 nm, and a temporal resolution of 1 d (day). Using the hyperspectral albedo maps, we estimate the spectral profiles of different land surfaces, such as forests, deserts, cities, and icy surfaces, and study their seasonal variability. These albedo maps will enable us to refine calculations of the Earth's energy budget and its seasonal variability and improve climate simulations.

Electromagnetic radiation reflection, transmission and absorption characteristics of charcoal-containing materials impregnated with chlorides aqueous solutions

The experimentally established regularities of changes in electromagnetic radiation reflection, transmission and absorption characteristics in the frequency range of 2.0–17.0 GHz of materials are presented. These materials contained powdered activated birch charcoal impregnated with chlorides aqueous solutions (calcium chloride, magnesium chloride and sodium chloride). Using the established regularities, it was determined that materials based on powdered activated birch charcoal impregnated with calcium chloride aqueous solution are radioabsorbing if they interact with electromagnetic radiation in the frequency ranges of 3.5–4.5 and 5.5–17.0 GHz. In turn, materials based on powdered activated birch charcoal impregnated with magnesium and sodium chlorides aqueous solutions are radioabsorbing if they interact with electromagnetic radiation in the frequency ranges of 2.0–17.0 and 2.0–7.5 GHz (magnesium chloride solution), 10.0–17.0 GHz (sodium chloride solution). Electromagnetic radiation absorption coefficient values of the studied materials reach 0.95. These materials seem promising for the manufacture of partitions to shield sectors of premises where electronic devices sensitive to electromagnetic interference are located.

Change of bioactive properties, spectral reflectance, and color characteristics of European cranberry (Viburnum opulus L.) juice as affected by foam mat drying technique

The European cranberry bush, known for its health benefits, can only be consumed through fermentation. This study aimed to develop a fruit leather made from European cranberry bush using quince seed gel and the foam drying method. For this purpose, quince seed gel was added to European cranberry juice to increase consistency. Then, European cranberry fruit leather was obtained by drying at 70, 80, and 90 °C air temperatures using foam mat drying technology. Spectral reflectance, color, drying kinetics, anthocyanin, ascorbic acid, and total phenolic content, antiradical activity, and macro-micronutrient concentrations of the resulting fruit pulp were investigated. The foam mat drying process at 90 °C had the greatest values of ascorbic acid (0.996 mg g− 1), anthocyanin (275.9 mg kg− 1), DPPH (47.77%), and ABTS.+ (68.76 µg TE g− 1). In addition, the highest value of total phenolic content (37.75 mg g− 1) was obtained in the foam mat drying process at 80 °C. The highest concentration of P, Na, Mg, K, Ca, and Mn in fruit leather was obtained at 70 °C, and the highest concentration of S, Cu, and Zn was obtained at 90 °C. The lowest spectral reflectance values were measured at 90 °C. In conclusion, the present study explored the fact that adding quince seed gel, extremely rich in biochemical content, significantly enhanced the bioactivity properties of European cranberry bush fruit leather.

Investigation on the reaction of sulphur with Ag–Cu–Zn-Ge alloy: Experimental and computational study

Silver and its alloys undergo tarnishing with time, which is a black stain on the surface due to the formation of Ag2S. Developing a tarnish resistant Ag alloy was attempted by alloying Ag with elements that form a passive oxide layer on the surface. Germanium is proven to provide better tarnish resistance to sterling Silver alloy (92.5 wt% pure) which is available under the trade name of Argentium©. The present work investigates the tarnish resistance behavior of sterling silver alloy (92.5 wt% pure) containing various additions of Copper, Zinc, and Germanium. The alloys were prepared by melting and casting route, followed by Passivation Heat Treatment (PHT) to create a stable and continuous oxide layer. The temperature for PHT was optimized using thermogravimetry analysis (TGA) of the alloys prepared. Accelerated tarnish test was carried out to investigate the tarnishing behavior of alloy samples obtained before and after PHT. The samples were characterized using XRD, SEM-EDX, and micro-Raman Spectroscopy. The change in reflectance of the samples after tarnish test is determined using UV–Visible reflectance spectroscopy. The mechanism behind the tarnish resistance was derived using Density Functional Theory (DFT) by comparing sulphur (S2) and Oxygen (O2) adsorption energies (BE) of the alloying elements. The lower value of S2 (BE)/O2 (BE) indicates better oxidation and tarnish resistance. The ratio ranges between 222 % (Pure Ag) and 132 % (for Ag-4.2Cu-2.8Zn-1.4Ge) and the p-p between Ge and O has contributed to the reduction in the ratio.

Temperature adaptive passive daytime radiative cooling: The impact of their essential properties on energy performance of different building types

Passive daytime radiative cooling (PDRC) materials can reduce building cooling demands during hot periods but increase heating needs in colder times, known as heating penalties, limiting their practicality. Temperature adaptive (TA) materials offer a solution, yet optimal TA PDRC properties, such as changes in reflectivity or emissivity from high surface temperature (HST) to low surface temperature (LST) states and the switch temperature at which these changes occur, are under-researched. To address this, a wavelength-dependent PDRC model was coupled with EnergyPlus to identify the optimal reflectivity or emissivity in HST and LST states and determine the appropriate switch temperature. Results show that different reflectivity and emissivity values are needed for various climates to maximize TA PDRC benefits. Switch temperatures from 15 °C to 30 °C primarily affect cooling benefits with minimal impact on heating penalties. Additionally, the heating penalty and cooling benefit of TA PDRC vary across building types, requiring alignment between TA PDRC operational characteristics and HVAC systems to optimize advantages. Among building types, malls benefit the most from PDRC application.

In-plane thermal conductivity measurements of Si μ-cantilevers using the suspended thermo-reflectance (STR) technique.

The Suspended Thermoreflectance (STR) technique is described in this paper. This optoelectronic measurement tool performs thermal characterization of freestanding micro-/nanoscale materials. STR performs thermal mapping at the submicron level and produces unconstrained thermal conductivity unlike other optical measurement techniques where independent conductivity measurement is not possible due to their reliance on heat capacity. STR works by changing the temperature of a material and collecting the associated change in light reflection from multiple points on the sample surface. Reflection is a function of the material being tested, the wavelength of the probe light, geometry, and the composition of the specimen for transparent and quasi-transparent materials. In this article, Si μ-cantilevers are studied. In addition, a thermal analytical model is developed and incorporated with optical equations to characterize the conductivity of the Si μ-cantilevers. The analytical model is compared with a finite element model to check its applicability in the STR experiment and data analysis. To validate the technique, the thermal conductivity of 2 and 3 µm thick Si μ-cantilevers was determined using STR at a temperature range of 20-350K and compared to simulations using the equation of phonon radiative transfer and literature values.

Estimation on powdery mildew of wheat canopy based on in-situ hyperspectral responses and characteristic wavelengths optimization

Wheat powdery mildew (WPM) mainly damages leaves, which leads to yield reduction. Although spectroscopy has been considered as one of the effective methods to detect crop diseases, the severity estimation of WPM is challenged by complex changes of wheat canopy reflection, wavelength redundancy in hyperspectral data, et al., so that to reduce the accuracy of disease index (DI) estimation. Aiming to estimate DI of WPM, an optimization method combined of band intervals and sensitive wavelengths screening was proposed by in-situ reflected spectral responses. Field experiments were conducted in 2022 and 2023. With regards to data processing, after preprocessing by Savitzky-Golay (SG) and multiplicative scatter correction (MSC) methods, the backward interval partial least squares (Bipls) method was used to featuring band interval. Then, the characteristic wavelengths in the selected interval were optimized by the variable important in projection (VIP), maximal information coefficient (MIC) and variable importance measure based on random forest (RFVIM) method, separately. Finally, partial least squares regression (PLSR) was used to establish the DI estimating model of WPM, and the best model was selected by comparing the performance among the models. The results indicate that the Bipls-VIP-PLSR model has the best performance (2022: =0.78, RMSEV =10.94%; 2023: =0.75, RMSEV=11.73%), and it was used to estimate the DI changes in the field. The distribution map of DI provided a potential for WPM monitoring and plant protection decision-making.

Influence of viscous shear boundary layers on the sound performance of acoustic metasurfaces

Acoustic metasurfaces are mostly designed in a static medium, ignoring the influence of flow characteristics. However, in actual aeroacoustic noise reduction, e.g., aircraft engine liner design, the background flow can have effects on the sound performance of acoustic metasurfaces, especially for a viscous shear flow. The effect of a viscous shear flow is often neglected in previous studies on the design and sound field prediction of acoustic metasurfaces. For considering the viscous and thermal dissipation effects, an analytical model is developed to predict the sound field of a periodic metasurface in a viscous shear boundary layer. In this model, the effective impedance based on the high-frequency limits is utilized to consider both the actual impedance of the acoustic metasurface and the effect of a finite-thickness viscous shear boundary layer. An acoustic metasurface designed in the static medium or even redesigned with only the effect of an inviscid shear flow is not suitable for wave manipulation when the Reynolds number (Re) changes significantly, since the viscosity is an important and non-negligible factor affecting the sound performance. For the cases in this work, the sound performance gradually deteriorates with the decrease in Re when Re≥5×106. When Re≤1×106, especially at Re=1×105, the existence of viscous shear flows could result in the destruction of expected anomalous reflection and significant intensity change of the reflected waves. This research provides a method for the design of acoustic metasurfaces under viscous shear flow conditions, which is significant for future aeroacoustic applications.

‘How far I’ve come’: the value of reviewing past written reflections

ABSTRACT Promoting reflection on experience and developing students’ reflective skills is an important element of curricula across the health professions. Students often do not find reflection easy and educators use a range of approaches to facilitate this. This qualitative study analysed final year medical students’ written reflections about important and difficult concepts they had encountered at medical school and personal change. As part of this, students were expected to look back on their written reflections from earlier years of the undergraduate programme. An initial analysis identified ‘learning from past reflections’ as an important theme. Here we report an in-depth analysis of this theme. Thirty-six final year volunteer students’ reflections were analysed and 6 themes identified where students explicitly referred to earlier written reflections. These were: managing emotions; holistic, patient-centred care; uncertainty and ambiguity; self-regulation; growth in identity and sense of self efficacy; and reflective practice changes. Asking students to reflect on past reflections appeared to help students identify personal change, and how their understanding of ‘important concepts’ and their views and approach to reflective practice have developed. Experienced by students as a motivating, profound, sometimes cathartic process, this activity could be a useful addition to reflective writing training in health professions.

Hyperspectral imaging for chloroplast movement detection.

We employed hyperspectral imaging to detect chloroplast positioning and assess its influence on common vegetation indices. In low blue light, chloroplasts move to cell walls perpendicular to the direction of the incident light. In high blue light, chloroplasts exhibit the avoidance response, moving to cell walls parallel to the light direction. Irradiation with high light results in significant changes in leaf reflectance and the shape of the reflectance spectrum. Using mutants with disrupted chloroplast movements, we found that blue-light-induced changes in the reflectance spectrum are mostly due to chloroplast relocations. We trained machine learning methods in the classification of leaves according to the chloroplast positioning, based on the reflectance spectra. The convolutional network showed low levels of misclassification of leaves irradiated with high light even when different species were used for training and testing, suggesting that reflectance spectra may be used to detect chloroplast avoidance in heterogeneous vegetation. We also examined the correlation between chloroplast positioning and values of indices of normalized-difference type for various combinations of wavelengths and identified an index sensitive to chloroplast positioning. We found that values of some of the vegetation indices, including those sensitive to the carotenoid levels, may be altered due to chloroplast rearrangements.

Glass serviceability limits: new evidence from human-centred studies

AbstractThe performance of the building envelope is crucial for minimizing operational carbon emissions of buildings and maintaining indoor comfort. Contemporary building envelopes, such as engineered glazed façades, achieve high performance levels but often add a significant amount of embodied carbon. There is therefore an incentive to reduce the thickness of the glass panels, but the minimum thickness possible is often not governed by strength or manufacturing limits but rather by the deflection (serviceability) limits. Despite objective criteria guiding serviceability limits, user acceptance of deformation remains unexplored, leading to conservative designs. This paper introduces a novel method for measuring user satisfaction with glass deformations, aiming to establish acceptance thresholds comparable to objective criteria. The study involves a novel experimental campaign to assess volunteers' levels of perception and acceptance of various glass deformations. The glass was deformed using a bespoke electro-pneumatic system at levels corresponding to below, above, and at the current serviceability limit. The results demonstrate the feasibility of measuring human responses to deformations in the glazing and provide essential data for setting serviceability limits. The experiments and corresponding user satisfaction feedback indicate that the current serviceability limit of L/50, may be relaxed, thereby presenting opportunities for material efficiency, such as the adoption of thinner glass in facades. The methodology effectively captures human responses, revealing that changes in reflection were the primary reason for the perception of movement; leading to a higher perception of glazing movement and a lower acceptance at night. Overall, participants felt safe regardless of their prior knowledge on glass properties, and providing this information to participants did not improve acceptance, which was already sufficiently high. The findings from this research fill an important knowledge gap in understanding user acceptance of glass deformations, crucial for comprehensive user satisfaction assessments and evidence-based reductions in glazing thickness.

Revealing complex subsurface dynamics with continuous seismic monitoring: Observations using distributed acoustic sensing and surface orbital vibrators during hydraulic fracturing

Understanding hydraulic fracturing is crucial to improving the stimulation of unconventional reservoirs and increasing fluid production. This study develops a novel seismic monitoring technology using distributed acoustic sensing (DAS) and surface orbital vibrators (SOV) to capture fracture seismic response and mechanical properties at high temporal intervals. We analyze continuous time-lapse vertical seismic profiling (VSP) data acquired every hour during the first nine days of treatment of an unconventional reservoir in the Austin Chalk/Eagle Field Laboratory. The VSP data contain clear seismic signals scattered from the activated fractures. The spatiotemporal changes of the fracture reflectivity revealed by the SOV/DAS data correlate well with the observations of fracture locations inferred from low-frequency DAS data. These results capture the fracture opening and closure processes, as well as highlight potential prestage activations of the fractures due to hydraulic connectivity with preexisting fracture systems. Therefore, analysis of the presented data set provides a unique opportunity to understand fracture initiation and subsequent evolution, not only in the context of unconventional resources but also in enhanced geothermal systems.

In Situ Studies on the Influence of Surface Symmetry on the Growth of MoSe2 Monolayer on Sapphire Using Reflectance Anisotropy Spectroscopy and Differential Reflectance Spectroscopy

The surface symmetry of the substrate plays an important role in the epitaxial high-quality growth of 2D materials; however, in-depth and in situ studies on these materials during growth are still limited due to the lack of effective in situ monitoring approaches. In this work, taking the growth of MoSe2 as an example, the distinct growth processes on Al2O3 (112¯0) and Al2O3 (0001) are revealed by parallel monitoring using in situ reflectance anisotropy spectroscopy (RAS) and differential reflectance spectroscopy (DRS), respectively, highlighting the dominant role of the surface symmetry. In our previous study, we found that the RAS signal of MoSe2 grown on Al2O3 (112¯0) initially increased and decreased ultimately to the magnitude of bare Al2O3 (112¯0) when the first layer of MoSe2 was fully merged, which is herein verified by the complementary DRS measurement that is directly related to the film coverage. Consequently, the changing rate of reflectance anisotropy (RA) intensity at 2.5 eV is well matched with the dynamic changes in differential reflectance (DR) intensity. Moreover, the surface-dominated uniform orientation of MoSe2 islands at various stages determined by RAS was further investigated by low-energy electron diffraction (LEED) and atomic force microscopy (AFM). By contrast, the RAS signal of MoSe2 grown on Al2O3 (0001) remains at zero during the whole growth, implying that the discontinuous MoSe2 islands have no preferential orientations. This work demonstrates that the combination of in situ RAS and DRS can provide valuable insights into the growth of unidirectional aligned islands and help optimize the fabrication process for single-crystal transition metal dichalcogenide (TMDC) monolayers.