Defect-Density-Controlled Phase-Change Phenomena.

Juxtaposing hydrophilicity and hydrophobicity on the same surface, known as hybrid surface engineering, can enhance phase-change heat transfer. However, controlling hydrophilicity on hybrid surfaces in a scalable fashion is a challenge, limiting their application. Here, using widely available metal meshes with variable dimensions and by controlling the patterning pressure, we scalably fabricate hybrid surfaces having spot and gridlike patterns using stamping. Using fog harvesting in a controlled chamber, we show that optimized hybrid surfaces have a ∼37% higher fog harvesting rate when compared to homogeneous superhydrophobic surfaces. Furthermore, condensation frosting experiments reveal that, on grid-patterned hybrid surfaces, frost propagates at ∼160% higher velocity and provides ∼20% less frost coverage when compared to homogeneous superhydrophobic surfaces. During defrost, our hybrid surfaces retain more water when compared to superhydrophobic surfaces due to the presence of hydrophilic patterns and melt water pinning. We adapt our fabrication technique to roll-to-roll patterning, demonstrating wettability contrast on round metallic geometries via atmospheric water vapor condensation. This work provides guidelines for the rapid, substrate-independent, and scalable fabrication of hybrid wettability surfaces for a wide variety of applications.

Durability and Degradation Mechanisms of Antifrosting Surfaces.

Rapid implementation of renewable energy technologies has exacerbated the potential for economic loss and safety concerns caused by ice and frost accretion, which occurs on the surfaces of wind turbine blades, photovoltaic panels, and residential and electric vehicle air-source heat pumps. The past decade has seen advances in surface chemistry and micro- and nanostructures that can promote passive antifrosting and enhance defrosting. However, the durability of these surfaces remains the major obstacle preventing real-life applications, with degradation mechanisms remaining poorly understood. Here, we conducted durability tests on antifrosting surfaces, including superhydrophobic, hydrophobic, superhydrophilic, and slippery liquid-infused surfaces. For superhydrophobic surfaces, we demonstrate durability with progressive degradation for up to 1000 cycles of atmospheric frosting-defrosting and month-long outdoor exposure tests. We show that progressive degradation, as reflected by increased condensate retention and reduced droplet shedding, results from molecular-level degradation of the low-surface-energy self-assembled monolayer (SAM). The degradation of the SAM leads to local high-surface-energy defects, which further deteriorate the surface by promoting accumulation of atmospheric particulate matter during cyclic condensation, frosting, and melt drying. Furthermore, cyclic frosting and defrost tests demonstrate the durability and degradation mechanisms of other surfaces to show, for example, the loss of water affinity of superhydrophilic surfaces after 22 days due to atmospheric volatile organic compound (VOC) adsorption and significant lubricant drainage for lubricant-infused surfaces after 100 cycles. Our work reveals the degradation mechanism of functional surfaces during exposure to long-term frost-defrost cycling and elucidates guidelines for the development of future surfaces for real-life antifrosting/icing applications.

Tunable Self-Assembled Peptide Hydrogel Sensor for Pharma Cold Supply Chain.

Defrost sensors are a crucial element for proper functioning of the pharmaceutical cold chain. In this paper, the self-assembled peptide-based hydrogels were used to construct a sensitive defrost sensor for the transportation and storage of medications and biomaterials. The turbidity of the peptide hydrogel was employed as a marker of the temperature regime. The gelation kinetics under different conditions was studied to detect various stages of hydrogel structural transitions aimed at tuning the system properties. The developed sensor can be stored at room temperature for a long period, irreversibly indicates whether the product has been thawed, and can be adjusted to a specific temperature range and detection time.

Transparent Electrothermal Film Defoggers and Antiicing Coatings based on Wrinkled Graphene.

Fog, frost, ice, and other natural phenomena can inevitably affect human life and the function of equipment. Therefore, removal or prevention is an urgent problem to be solved. As a new type of 2D material, graphene possesses great application potential in defogging and antiicing. In this work, a graphene film with intentionally increased defects and uniformly distributed wrinkles is synthesized on copper-zinc alloy substrates by chemical vapor deposition, and transparent electrothermal film defoggers are prepared based on such material. The defoggers can completely remove fog within 5 s when supplying a safe voltage of 28 V. The surface resistance of the defoggers is sensitive to humidity and it can monitor the defogging process in real time. Such outstanding performance is attributed to the ultrafast evaporation mechanism, which can prevent excessive water accumulation. The antiicing performance of wrinkled graphene (WG) is further studied. The antiicing coatings can delay freezing for 1.25 h at -15 °C or 2.8 h at -10 °C. The superior performance of WG can be explained by its unique surface structure and nanoscale roughness. Taken together, WG is expected to be used in antifog glass, rearview mirror defogging, aircraft surface deicing, and other applications.

Perda por degelo em carcaças de frangos congeladas / Ice break up loss on frozen chicken carcasses

O consumo de frango congelado aumentou nos últimos anos. O fator de degelo, água absorvida pelo músculo da ave durante o processamento industrial, é um indicador de qualidade e economicidade para este produto. Com objetivo de avaliar perdas de peso por degelo em carcaças de frango, por meio do método de gotejamento (Drip test), foram analisadas 25 amostras de 5 diferentes marcas (10 evisceradas e 15 não evisceradas). Os resultados das amostras individuais demonstraram que das 25 amostras, 14 amostras (56%) evidenciaram perda por degelo acima do permitido pela legislação pertinente que é de 6%. Observou-se também que as amostras com vísceras tiveram médias de perda por degelo bem superiores àquelas evisceradas: 7,3% e 5,2%, respectivamente. Considerando valores médios de 5 amostras por marca, apenas as com vísceras apresentaram não conformidade em relação à perda de peso por degelo. Todas as amostras contendo vísceras apresentaram irregularidades e 20% das amostras evisceradas tiveram percentual de degelo ligeiramente acima do máximo permitido. Diante dos resultados concluiu-se que: as condições "eviscerado" e "não eviscerado" influenciaram sobremaneira os valores de perda por degelo, que a maioria das amostras analisadas apresentou percentuais elevados de degelo e que a aquisição de carcaça eviscerada é a melhor opção de compra para este tipo de produto considerando a economicidade.

As principais contribuições de Winnicott à prática clínica / Las principales contribuiciones de Winnicott a la práctica clínica / Winnicott's main contributions to clinical practice

O trabalho de Winnicott abre-nos possibilidades de analisar pacientes difíceis, com a teoria do “amadurecimento pessoal” e o uso dos fenômenos de “regressão à dependência” na interação paciente/analista, que fornece o holdingnecessário e deve decidir quando falar e quando silenciar, particularmente nas situações de “descongelamento” do trauma, quando a aceitação das críticas do paciente às falhas do analista, sem revidar ou se justificar, é um importante elemento de retomada do desenvolvimento, sobretudo em casos de pacientes bordelines, esquizóides e narcísicos graves, nos quais o mais importante é a “sobrevivência do analista.

El trabajo de Winnicott abre posibilidades de analizar pacientes difíciles, con la teoría de la “maduración personal” y el uso de los fenómenos de “regresión a la dependencia” en la interacción paciente y analista, que ofrece el holding necesario y debe decidir cuando hablar y cuando silenciar, particularmente en las situaciones de “descongelamiento” del trauma, cuando la aceptación de las críticas del paciente a las fallas del analista, sin retrucar o justificarse, es un elemento importante de retomada del desarrollo, sobre todo en los casos de pacientes bordelines, esquizoides y narcísicos graves, donde lo más importante es la “supervivencia del analista.

Winnicott offers possibilities of analysing difficult patients, with theory on “personal maturation” and the usage of “regression to dependence” phenomenon in the interaction between patient and analyst, which supplies the necessary “holding” and has to decide when to speak and when to be silent, mainly in trauma “defrosting” situations, in which acceptance of patient’s criticism towards the analyst’s faults, lacking revenge or justification, is an important element for reconducting development, mainly in cases of borderline, schizoid and severely narcissistic patients, where the most important aspect is the “analyst’s survival”.