Controlled Humidity Conditions Research Articles

Prediction of Residual Compressive Strength after Impact Based on Acoustic Emission Characteristic Parameters.

This study proposes a prediction method for residual compressive strength after impact based on the extreme gradient boosting model, focusing on composite laminates as the studied material system. Acoustic emission tests were conducted under controlled temperature and humidity conditions to collect characteristic parameters, establishing a mapping relationship between these parameters and residual compressive strength under small sample conditions. The model accurately predicted the residual compressive strength of the laminates after impact, with the coefficient of determination and root mean square error for the test set being 0.9910 and 2.9174, respectively. A comparison of the performance of the artificial neural network model and the extreme gradient boosting model shows that, in the case of small data volumes, the extreme gradient boosting model exhibits superior accuracy and robustness compared to the artificial neural network. Furthermore, the sensitivity of acoustic emission characteristic parameters is analyzed using the SHAP method, revealing that indicators such as peak amplitude, ring count, energy, and peak frequency significantly impact the prediction results of residual compressive strength. The machine-learning-based method for assessing the damage tolerance of composite laminates proposed in this paper utilizes the global monitoring advantages of acoustic emission technology to rapidly predict the residual compressive strength after the impact of composite laminates, providing a theoretical approach for online structural health monitoring of composite laminates. This method is applicable to various composite laminate structures under different impact conditions, demonstrating its broad applicability and reliability.

In vitro Cytotoxicity and Genotoxicity/Antigenotoxicity Evaluation of Encapsulated Black Garlic Extracts on A549 Cells

Objectives: Black garlic is produced by fermenting fresh garlic under controlled temperature and humidity conditions for an extended period. Due to its sweeter taste and lack of pungent odor compared to fresh garlic, black garlic is easier to consume. Moreover, the increase in bioactive compounds such as polyphenols and flavonoids during fermentation has sparked interest in studying the health effects of black garlic. It is known that different fermentation and extraction methods can lead to variations in biological activities. Therefore, analyzing the effectiveness of black garlic processed by different methods is of critical importance. In our study, we investigated the cytotoxic, genotoxic, and antigenotoxic effects of different concentrations of encapsulated black garlic capsule extract (BGC) on lung cancer cells. Methods: The A549 cell line was used to investigate the effects of BGC. Cells treated with BGC at different concentrations (10, 25, 50, 100, 125, 250, 500, and 1000 µg/mL) for 24 hours were subjected to MTT and NRU assays to examine the cytotoxic effects. Alkaline comet assay was performed to investigate genotoxic and antigenotoxic effects. For antigenotoxicity analysis, cells pretreated with BGC were exposed to H2O2 to explore the protective effects of BGC. Results: According to the MTT results, cell viability remained at 90% even at concentrations higher than 125 µg/mL. However, in the NRU analysis, viability decreased to less than 70% at concentrations ranging from 50 µg/mL. Comet assay results revealed significant increases in tail length and tail intensity at different concentrations (specifically, at 250 µg/mL and above and at 50 µg/mL and 100 µg/mL, respectively). However, tail moments did not show any significant differences at any concentration. Additionally, BGC significantly reduced H2O2-induced DNA damage. Conclusions: Our research demonstrated that BGC reduces the viability of lung cancer cells and can have genotoxic effects. Additionally, its protective effect against oxidative damage was shown at the DNA level. Based on these data, further research can be conducted on the use of BGC against cancer.

Accelerated carbonation of waste paper fly ash by liquid process (NaHCO3) for stabilization of Ba and Pb

The increase of energy valorization of paper sludge waste and biomass due to their high calorific value by incineration leads to an increase of waste paper fly ash (WPFA) quantities, which are in most cases considered as hazardous, and must be dealt with accordingly. The Alternative options for the management of WPFA, such as stabilization/solidification, vitrification or sintering, are not fully developed or either costly. In the present study, accelerated carbonation technology was used to reduce the hazardous nature of WPFA by improving the stabilization of metallic and metalloids trace elements (MMTE), especially Barium (Ba) and Lead (Pb) leaching. The accelerated carbonation of WPFA was found to be optimal at a water/solid ratio of 0.3 L/kg under controlled temperature and humidity conditions. The use of water saturated with 25% sodium bicarbonate (NaHCO3) improved the carbonation of WPFA and the stabilization of Ba and Pb. Batch leaching tests based on thermodynamic equilibrium was used to evaluate the solubility of the MMTE as a function of pH and at the natural pH of non‑carbonated and carbonated WPFA. Thermogravimetry, X-ray diffraction, scanning electron microscopes and energy dispersive spectroscopy analyses were performed to investigate the evolution of carbonation over time and its effect on the chemical and mineralogical properties of WPFA. After 30 days of accelerated carbonation, the leaching concentration of Ba and Pb was below the French legal limit. The leaching concentration of Ba and Pb from carbonated samples decreased 99% and 99.5% respectively. The leaching and release potential behavior of carbonated WPFA were further evaluated using the four-step sequential extraction procedure proposed by the Commission of the European Communities Bureau of Reference (BCR). The speciation of MMTE underwent significant transformation, shifting predominantly from the soluble fraction to the carbonated fraction as a result of the carbonation reaction.

Potential effects of soil petroleum contamination on decomposition of Artemisia annua plant litter.

The accumulation of petroleum contaminants in phytoremediating plants can significantly impact the decomposition of their litter. However, the mechanisms underlying these effects and the potential influence of the contaminant concentration remain unclear. In this study, litter from Artemisia annua plants grown in soil with varying concentrations of petroleum (0, 15, 30, and 45 g kg-1) was collected. The litter samples were then inoculated with soil microorganisms and subjected to an indoor simulation of decomposition under controlled temperature and humidity conditions. Changes in the chemical properties, activities of decomposition-related enzymes in the litter, and decomposition rates were measured. Additionally, structural equation modeling was employed to analyze the mechanism through which soil petroleum contamination affects litter decomposition. The findings revealed several key points: (1) increasing soil petroleum contamination tended to reduce the concentration of carbon and nitrogen in litter while increasing those of lignin and total petroleum hydrocarbons (TPH). (2) Soil petroleum contamination tended to increase the activities of both total lignocellulases and total nutrient cycling-related enzymes in litter. (3) Soil petroleum contamination might indirectly inhibit the activity of lignocellulases by increasing the concentration of lignin and TPH in litter. However, it might also directly accelerate the activity of these enzymes, resulting in contradictory effects on litter decomposition. (4) Finally, A. annua litter produced in soil contaminated with 15 and 30 g kg-1 of petroleum exhibited significantly lower decomposition rates than that from uncontaminated soil.

Elephant Black Garlic's Beneficial Properties for Hippocampal Neuronal Network, Chemical Characterization and Biological Evaluation.

Garlic has been used for decades as an important food and additionally for its beneficial properties in terms of nutrition and ancestral therapeutics. In this work, we compare the properties of fresh (WG) and aged (BG) extract obtained from elephant garlic, harvested on Chiloe Island, Chile. BG was prepared from WG with a 20-day aging process under controlled temperature and humidity conditions. We observed that in BG, compounds such as diallyl disulfide decrease, and compounds of interest such as 5-hydroxymethylfurfural (69%), diallyl sulfide (17%), 3H-1,2-Dithiole (22%) and 4-Methyl-1,2,3-trithiolane (16%) were shown to be increased. Using 2,2-diphenyl-1-picrylhydrazyl (DPPH, BG: 51 ± 5.7%, WG: 12 ± 2.6%) and 2,20-azino-bis-(3-ethylbenzothiazoline-6 sulfonate) diammonium salt (ABTS, BG: 69.4 ± 2.3%, WG: 21 ± 3.9%) assays, we observed that BG possesses significantly higher antioxidant activity than WG and increased cell viability in hippocampal slices (41 ± 9%). The effects of WG and BG were shown to improve the neuronal function through an increased in intracellular calcium transients (189 ± 4%). In parallel, BG induced an increase in synaptic vesicle protein 2 (SV-2; 75 ± 12%) and brain-derived neurotrophic factor (BDNF; 32 ± 12%) levels. Thus, our study provides the initial scientific bases to foster the use of BG from Chiloe Island as a functional food containing a mixture of bioactive compounds that may contribute to brain health and well-being.

Anomalous increase of leakage current in epoxy moulding compounds under wet conditions

An interdigitated capacitor embedded in the EMC has been realized and characterized under controlled humidity conditions by applying a DC step voltage and monitoring the leakage current as a function of time. Both experimental characterization and TCAD simulations of dry and wet EMC samples have been carried out to fully understand the involved charge transport mechanisms. The anomalous increase of current with time in wet conditions is explained assuming a build-up of space charge directly induced by the high-injection at the metal electrodes. The assumption is confirmed by TCAD simulations.

Understanding optical and structural properties of the CH3NH3PbI3 nanocrystal thin films under humidity conditions

Low-dimensional organic-inorganic hybrid perovskite materials have drawn a lot of interest in optoelectronic applications because of their unique optoelectronic performance in comparison to their bulk counterparts. There is an influence of humidity conditions on the stability of perovskite in both positive and negative ways. The passivation of surface and bulk defects in the thin film of perovskite by the H2O molecules is a positive way. The negative way is that the material's stability will hinder the commercialization of perovskite-based devices. Herein, CH3NH3PbI3 nanocrystals are synthesized by the hot-injection method. The optical and structural properties of the thin film of the synthesized nanocrystals under different humidity conditions are studied through photoluminescence (PL), TRPL, Raman, X-ray diffraction (XRD), UV–Vis, spectroscopic ellipsometry, and FTIR techniques for 4 weeks. The redshift in the PL spectra of the thin film with an increase in PL intensity and carrier lifetime is caused by the shallow trap-assisted radiative recombination and localization of the charge carriers at the interface of the CH3NH3PbI3/water. The XRD, Raman, and FTIR peaks of the thin film are also shifted due to defect formation and structure distortion of the CH3NH3PbI3 crystal lattice. The thin films of these nanocrystals exhibit very high PLQY of 56% and 60% after 5 h and 1 week respectively. The results pave the way to analyse the stability of CH3NH3PbI3 nanocrystals through their optical and structural behaviour under different humidity conditions. The results also reflect that the photoemission of the synthesized material can be tuned by regulating the defect density and the structural deformation of the nanocrystals under controlled humidity conditions.

The topical application of different galenic formulations can alter the thermographic images of skin: Limitations for public thermal screening on infection control situations

To analyze whether the application of topical formulas as cosmetics or sunscreens could affect the skin thermographic readings in terms of infection control in pandemic situations. The temperature of the skin of the dorsal region of the back and the face of 20 volunteers was followed after the application of 6 different types of gels, sunscreens, and make-up under controlled temperature and humidity conditions. High-resolution thermographic images were analyzed to calculate the temperature of treated skin compared to skin free of topical products. The application of hydroalcoholic gel resulted in a mean drop of more than 2°C just after 1minute followed by organic sunscreens until 1.7°C. Recovery was observed progressively until minute 9. Color make-up type formulas, rich in iron oxide as well as sunscreens with mineral filters had little or no effect on the skin thermal response. It is possible to alter the skin temperature almost immediately by using hydroalcoholic gels and sunscreen cosmetics. So, it is possible to produce false negative data in the readings of patients screened thermically.

Achieving a full color palette with thickness, temperature, and humidity in cholesteric hydroxypropyl cellulose

Hydroxypropyl cellulose (HPC) is a sustainable, cost-efficient, and bio-compatible cellulose derivative that forms cholesteric liquid crystalline phases in highlyconcentrated water solutions that reflects colour in the visible range. While there have been studies exploiting HPC’s structural coloration and transferring the cholesteric order of the solutions into solid form via cross-linking, there is still lack of understanding on the thermotropic mechanisms that enable the transfer of the structural ordering of the pure HPC at higher temperatures. In this work, we demonstrate the balance between the temperature, humidity, and film thickness to achieve a full color palette of pure HPC. We reveal that at the early stages of the evaporation, formation of a dense skin over the lyotropic phase facilitates the thermal expansion of the HPC during the heat treatment. Increasing the thickness, applying higher drying temperatures, and exposing the samples to higher humidity during the evaporation all result with increased pitch values that cause a red-shift in coloration in the solid state. Our analysis of the HPC samples dried in controlled temperature and humidity conditions at a fixed thickness provided an understanding of the dominance of the thermal expansion which drives the final structural organization in the solid cholesteric phase. When the thickness of the films was varied against fixed temperature and humidity conditions, the color shift from red to violet follows the thickness gradient of the sample due to the change in the drying time required to reach the solid form.

Mixed-frequency medium-voltage aging analysis of epoxy in the absence of partial discharges and dielectric heating

Premature failures of polymeric insulation under inverter-type electrical stress are predominantly associated with partial discharge (PD) erosion or dielectric heating. In the present contribution, an approach for aging analysis in the absence of the aforementioned mechanisms is proposed and applied to anhydride-cured epoxy samples, which are designed with a recessed shape to achieve PD-free aging. Dielectric heating was found to be negligible under all applied experimental conditions. Aging of samples was performed with a specialized setup for the generation of mixed-frequency medium-voltage (MF-MV) waveforms under controlled temperature and humidity conditions. The health state of samples was evaluated before and after different aging sequences by analysis of potential aging markers, namely the short-term AC breakdown strength, the complex dielectric permittivity (real and imaginary part), the volume resistivity, the glass transition temperature and the characteristic absorbance peaks obtained by Fourier-transform infrared spectroscopy (FTIR). Of these, only the breakdown strength exhibited significant aging effects under hygroelectric stress, which is hypothesized to be attributed to localized microcracking caused by electromechanical stress. Pure electrical MF-MV stress (i.e. at room temperature and dry conditions) was not found to be critical under the applied experimental conditions. By means of FTIR, hydrolysis was excluded as a possible aging mechanisms. In summary, the proposed aging analysis approach was found to be suitable to reveal aging effects empirically as well as to give indications about the underlying aging mechanisms without the need for excessively long or accelerated lifetime testing.

P‐15.2: Light Output Degradation of Full‐frame Projection Laser Displays

Laser display technology can be applied to laser TV, laser projector and other products. In different applications, laser sources have different quantity and packages of lasers. Laser display technology has the advantages of large color gamut, high brightness and low power consumption. One of the benefits of laser is the narrow spectral bandwidth. As a consequence, the display can have a very large color gamut. Affected by a number of factors, the light output of laser display could possibly change with the operation time. Some failure factors of optical elements composing full‐frame projection laser displays that contribute to the degradation of light output are summarized, and under controlled temperature and humidity conditions, the light output degradation of two groups of DUTs were tested.

Morphology Effect of Photoconverted Silver Nanoparticles on the Performance of Surface-Enhanced Raman Spectroscopy Substrates.

Nowadays, surface-enhanced Raman spectroscopy (SERS) substrates are of great interest for many researchers, aiming to fabricate substrates with high sensitivity and low fabrication costs. In this study, we photoconverted Ag nanoparticles by using a simple and affordable red-green-blue light-emitting diode photoreactor. The obtained dispersions were transformed into a paste of nanoparticles and used to fabricate SERS substrates by a simple drop-casting process under controlled humidity conditions. The performance of these substrates was tested using p-aminothiophenol as a Raman probe. The results indicate that the particle shape has an influence on the Raman intensities and substrate sensitivity, showing a significant enhancement as the number of faces and vertices in the particle increases.

A comprehensive study of the effect of thermally induced surface terminations on nanodiamonds electrical properties

Nanodiamonds (NDs) gained increasing attention in multiple research areas due to the possibility of tuning their physical and chemical features by functionalizing their surface. This has a crucial impact on their electrical properties, which are essential in applications such as the development of innovative sensors and in the biomedical field. The great interest in electrical conduction in NDs has driven the scientific community to its extensive investigation. The role of various functionalities has been considered and different conduction mechanisms have been proposed. In this work, we reported on a systematic study of the modification of the electrical properties of differently sized NDs, as a function of different thermal treatments in air, hydrogen or inert atmosphere. Samples were electrically characterized in controlled humidity conditions to consider the influence of water on conductivity. NDs electrical properties were interpreted in connection with their surface chemistry and structural features, probed with infrared and Raman spectroscopies. The presence of surface graphite, hydrogen terminations or water adsorbed on hydrophilic oxygen-containing functional groups rendered NDs more conductive. These moieties indeed enabled different conduction mechanisms, which were respectively graphite-mediated conduction, water-induced transfer doping and Grotthus mechanism in surface-adsorbed water. The effect of particles size on conductivity has also been evaluated and discussed. Our experimental findings shed light on the link between surface modifications and electrical properties of NDs, providing at the same time an interpretative key to understanding the effect of particles dimensions.

Dried human-cultured epidermis accelerates wound healing in a porcine partial-thickness skin defect model.

Autologous cultured epidermis (CE) is an effective approach for overcoming the deficiency of donor sites to treat extensive burns. However, the production of autologous CE takes 3-4 weeks, which prevents its use during the life-threatening period of severe burns. In contrast, allogeneic CE can be prepared in advance and used as a wound dressing, releasing several growth factors stimulating the activity of recipient cells at the application site. Dried CE is prepared by drying CEs under controlled temperature and humidity conditions until all the water is completely removed and no viable cells are present. Dried CE accelerates wound healing in a murine skin defect model and is potentially a new therapeutic strategy. However, the dried CE safety and efficacy have not yet been studied in large animal models. Therefore, we studied the safety and efficacy of human-dried CE in wound healing using a miniature swine model. Human CE was manufactured using Green's method from donor keratinocytes. Three types of CEs (Fresh, Cryopreserved, and Dried) were prepared, and the ability of each CE to promote keratinocyte proliferation was confirmed invitro. Extracts of the three CEs were added to keratinocytes seeded in 12-well plates, and cell proliferation was evaluated using the WST-8 assay for 7 days. Next, we prepared a partial-thickness skin defect on the back of a miniature swine and applied three types of human CE to evaluate wound healing promotion. On days 4 and 7, the specimens were harvested for hematoxylin-eosin, AZAN, and anti-CD31 staining to assess epithelialization, granulation tissue, and capillary formation. The conditioned medium containing dried CE extract significantly enhanced keratinocyte proliferation compared to the control group (P<0.05). Invivo experiments revealed that human-dried CE significantly accelerated epithelialization at day 7 to the same extent as fresh CE, compared to the control group (P<0.05). The three CE groups similarly affected granulation formation and neovascularization. Dried CE accelerated epithelialization in a porcine partial-thickness skin defect model, suggesting that it may be an effective burn treatment alternative. A clinical study with a long-term follow-up is needed to assess the applicability of CEs in clinics.

Study of the water content on the CdO + CdTiO3 crystalline grains distribution in thin films obtained by sol-gel and their effect on the morphological, optical, and photocatalytic properties

CdO+CdTiO3 multicomponent oxide thin films were obtained by mixing the CdO and TiO2 sol-gel precursor solutions, keeping Ti/Cd = 0.65. TiO2 solution water content was varied from 0 to 5 mol (X) for each Ti mol in steps of 1 mol to evaluate its effect on the properties of the CdO+CdTiO3 films. The films were obtained by the dip coating method under controlled temperature and relative humidity conditions. Superficial morphology images by optical and scanning electron microscopy revealed a strong effect of the water content on the CdO and CdTiO3 crystalline grains distribution, showing three different zones. This result was remarked from X-ray diffraction, EDS measurements, UV-Vis, and Raman spectroscopy. In addition, the photocatalytic activity of CdO+CdTiO3 films was evaluated from the methylene blue in water photobleaching. For the first time, a notable effect of the distribution and content of CdO and CdTiO3 crystalline grains on the photocatalytic activity of the films is reported. The best photocatalytic activity (k = 0.66 h−1) is obtained for the films deposited with X = 4 mol, corresponding to those with crystalline grains distribution most homogeneous. Also, for these films, the highest Cd excess content to Ti is found (30%), so the highest photocatalytic activity is explained by the higher amount of CdO and CdTiO3 crystalline grains coupled.

Humidity-driven degradation of sputtered molybdenum oxide and molybdenum–titanium-oxide thin films

IR measurements reveal the enhanced hydrolysis resistance of molybdenum titanium oxide compared to molybdenum oxide when exposed to controlled humidity conditions.

The discovery of new cocrystals of 5-fluorocytosine using amine–carboxylate supramolecular synthon

Supramolecular synthon strategy is an often-employed principle to guide the discovery of novel pharmaceutical cocrystals. The amine–carboxylate (N–H···―OOC) intermolecular interaction has been confirmed as a member of the supramolecular toolbox, and a cocrystal of 5-fluorocytosine (FC) with L-proline (FC–L-PRO) containing this heterosynthon was previously harvested. Herein, two new cocrystals of FC with sarcosine (SAR) or dimethylglycine (DMG) were successfully screened out. Similar to FC–L-PRO, the N–H···―OOC synthon presents as the most important hetero-molecular interaction between FC and SAR/DMG in their crystal structures. And the FC molecular ribbons via homo-molecular N–H⋯N and N–H⋯O hydrogen bonds were observed in all of the cocrystal structures, which also exist in the structure of FC. Theoretical calculations show that the formations of FC–L-PRO and FC–DMG are thermodynamically favorable. While for FC–SAR–MeOH, the calculated result is not applicable. The coformer competitive experiments reveal that FC–L-PRO and FC–DMG have similar relative stability and FC–SAR–MeOH is the relative unstable form. These cocrystals exhibit weakened physical stability under high humidity condition (75% RH), then should be stored in controlled humidity conditions (≤50% RH). Additionally, FC–L-PRO demonstrates reduced intrinsic dissolution rate (IDR) in pH 1.2 medium (simulated gastric fluid), which may provide positive contribution to alleviate its toxic side effects.

Copper formulations in bacterial blight control and toxic effects on coffee seedlings

Bacterial blight of coffee (Pseudomonas syringae pv. garcae) is an important coffee disease and can be controlled using antibiotics and copper-based compounds. However, copper-based compounds raise doubts among coffee growers regarding bacterial blight control efficiency and phytotoxic potential. In this work, coffee plants were sprayed with different copper molecules in order to study their efficiency on bacterial blight control and the phytotoxic potential. Seven copper formulations, cuprous oxide, copper oxychloride, copper nitrate, copper hydroxide 1 (water-dispersible granules) and 2 (concentrated suspension), copper sulfate 1 (complexed with gluconic acid) and 2 (Bordeaux mixture) were studied. The copper formulations efficiency was compared with the antibiotic kasugamycin, saline solution, and control. In controlled environmental conditions of temperature, relative humidity, and photoperiod, coffee seedlings were sprayed with the treatments and after 24 hours they were inoculated with Pseudomonas syringae pv. garcae suspension. Disease incidence and severity assessments were performed in a 2-day interval during a 16-day period. Phytotoxicity incidence and severity, mapping, and quantification of copper on the leaf tissue surface, dried leaves weight, and total copper leaf content were assessed 16 days after pathogen inoculation. Data were submitted to the Scott-Knott test (p &lt; 0.05). Cuprous oxide and copper sulfate 2 proved most efficient to bacterial blight control, causing lower phytotoxicity effect, best covering, and persistence on leaf tissues. Copper nitrate and copper sulfate complexed with gluconic acid were more phytotoxicity compared to other copper formulations.

Egg development and viability in three species of Cyclocephala (Coleoptera: Scarabaeidae: Dynastinae).

Different species of Cyclocephala scarab beetles (Scarabaeidae, Dynastinae) perform key functional roles in both natural and agricultural systems, such as the cycling of organic matter and pollination, while also being known as destructive pests both as immatures and adults. Therefore, the identification of biological parameters is crucial for defining strategies for their conservation and efficient pest management. In a forest fragment within the Brazilian Atlantic Forest biodiversity hotspot, we field-captured adult individuals of Cyclocephala cearae, C. celata, and C. paraguayensis then reared and bred them under controlled temperature and humidity conditions. On a daily basis, we individually weighted eggs of all three species, from oviposition until hatching, and monitored egg development parameters (i.e., incubation duration, viability, and egg weight increase). Our findings provide novel empirical evidence showing (i) a positive correlation between egg weight and incubation duration, (ii) idiosyncratic characteristics on egg development, and (iii) a negative (involuntary) effect of manipulation on egg development and viability. Thus, the successful breeding and rearing of Cyclocephala spp. is correlated with egg integrity and the targeted species. Our analyses present a quantitative understanding of the egg phase and can assist in refining strategies for ovicidal activity and pest management of Cyclocephala spp. in agriculture systems. Moreover, they can provide a basis for new studies related to captivity breeding, pollinator management, and developmental biology for biodiversity conservation.

Drop impact of dairy product solutions at the onset of drying

Vertical impacts of heated dairy product droplets onto stainless steel surfaces have been experimentally studied using high-speed photography. The experiments were carried out under conditions of controlled temperature and humidity within an environmental chamber, and a numerical model was used to simulate the initial heating and evaporation processes. The droplets consisted of non-Newtonian (shear-thinning) solutions of infant formula or whole milk reconstituted at 45 wt % total solids content in water. Data obtained from image analysis were used to determine the effect of air and surface temperatures up to 140 °C on droplets during impact and spreading. The results show that drop spreading following an initial drying treatment depends on the type of drying applied. Droplets spread further with increasing air temperature, whereas it was found that surface temperatures below 120 °C only had a minor effect on droplet spreading. Moreover, the drops spread less with increasing chamber air temperature when they were air-dried at room temperature in an acoustic levitator for two minutes prior to impact. These trends have been analysed by considering the fluid viscosity, which decreases with temperature in bulk samples, but increases within any outer crust of dried liquid. Impacts were recorded for drop diameters in the range 1.5–3 mm at an impact velocity of 2.90 ± 0.03 m/s. This research should assist with understanding spray-drying of dairy products, and will be more broadly applicable to drop impacts involving heat flows and complex, non-Newtonian fluids.