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β-phase gallium oxide (Ga2O3) is an emerging ultrawide bandgap (UWBG) semiconductor (EG ∼ 4.8 eV), which promises generational improvements in the performance and manufacturing cost over today's commercial wide bandgap power electronics based on GaN and SiC. However, overheating has been identified as a major bottleneck to the performance and commercialization of Ga2O3 device technologies. In this work, a novel Ga2O3/4H-SiC composite wafer with high heat transfer performance and an epi-ready surface finish has been developed using a fusion-bonding method. By taking advantage of low-temperature metalorganic vapor phase epitaxy, a Ga2O3 epitaxial layer was successfully grown on the composite wafer while maintaining the structural integrity of the composite wafer without causing interface damage. An atomically smooth homoepitaxial film with a room-temperature Hall mobility of ∼94 cm2/Vs and a volume charge of ∼3 × 1017 cm-3 was achieved at a growth temperature of 600 °C. Phonon transport across the Ga2O3/4H-SiC interface has been studied using frequency-domain thermoreflectance and a differential steady-state thermoreflectance approach. Scanning transmission electron microscopy analysis suggests that phonon transport across the Ga2O3/4H-SiC interface is dominated by the thickness of the SiNx bonding layer and an unintentionally formed SiOx interlayer. Extrinsic effects that impact the thermal conductivity of the 6.5 μm thick Ga2O3 layer were studied via time-domain thermoreflectance. Thermal simulation was performed to estimate the improvement of the thermal performance of a hypothetical single-finger Ga2O3 metal-semiconductor field-effect transistor fabricated on the composite substrate. This novel power transistor topology resulted in a ∼4.3× reduction in the junction-to-package device thermal resistance. Furthermore, an even more pronounced cooling effect is demonstrated when the composite wafer is implemented into the device design of practical multifinger devices. These innovations in device-level thermal management give promise to the full exploitation of the promising benefits of the UWBG material, which will lead to significant improvements in the power density and efficiency of power electronics over current state-of-the-art commercial devices.

Heteroepitaxy of β-phase gallium oxide (β-Ga2O3) thin films on foreign substrates shows promise for the development of next-generation deep ultraviolet solar blind photodetectors and power electronic devices. In this work, the influences of the film thickness and crystallinity on the thermal conductivity of (201)-oriented β-Ga2O3 heteroepitaxial thin films were investigated. Unintentionally doped β-Ga2O3 thin films were grown on c-plane sapphire substrates with off-axis angles of 0° and 6° toward ⟨1120⟩ via metal-organic vapor phase epitaxy (MOVPE) and low-pressure chemical vapor deposition. The surface morphology and crystal quality of the β-Ga2O3 thin films were characterized using scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. The thermal conductivities of the β-Ga2O3 films were measured via time-domain thermoreflectance. The interface quality was studied using scanning transmission electron microscopy. The measured thermal conductivities of the submicron-thick β-Ga2O3 thin films were relatively low as compared to the intrinsic bulk value. The measured thin film thermal conductivities were compared with the Debye-Callaway model incorporating phononic parameters derived from first-principles calculations. The comparison suggests that the reduction in the thin film thermal conductivity can be partially attributed to the enhanced phonon-boundary scattering when the film thickness decreases. They were found to be a strong function of not only the layer thickness but also the film quality, resulting from growth on substrates with different offcut angles. Growth of β-Ga2O3 films on 6° offcut sapphire substrates was found to result in higher crystallinity and thermal conductivity than films grown on on-axis c-plane sapphire. However, the β-Ga2O3 films grown on 6° offcut sapphire exhibit a lower thermal boundary conductance at the β-Ga2O3/sapphire heterointerface. In addition, the thermal conductivity of MOVPE-grown (201)-oriented β-(AlxGa1-x)2O3 thin films with Al compositions ranging from 2% to 43% was characterized. Because of phonon-alloy disorder scattering, the β-(AlxGa1-x)2O3 films exhibit lower thermal conductivities (2.8-4.7 W/m·K) than the β-Ga2O3 thin films. The dominance of the alloy disorder scattering in β-(AlxGa1-x)2O3 is further evidenced by the weak temperature dependence of the thermal conductivity. This work provides fundamental insight into the physical interactions that govern phonon transport within heteroepitaxially grown β-phase Ga2O3 and (AlxGa1-x)2O3 thin films and lays the groundwork for the thermal modeling and design of β-Ga2O3 electronic and optoelectronic devices.

Engineering nano- and microscale systems for water filtration, drug delivery, and biosensing is enabled by the intrinsic interactions of ionic compounds in aqueous environments and limited by our u...

In this investigation, equilibrium molecular dynamics simulations were conducted to assess the influence of the interface modeling approach on the calculation of hydrodynamic slip in carbon nanochannels. A Green-Kubo formalism was implemented for the calculation of the slip length in water confined by graphite layers. The nonbonded interactions between solid and liquid atoms (interface models) were modeled using parameters optimized to represent the wetting behavior and adsorption energy curves from electronic structure calculations. Conventional carbon-oxygen-only interaction models were compared against comprehensive models able to represent the molecular-orientation-dependent energy of interaction. Quasi-universal relationships built under the premise of the slip length dependence on the water-graphite affinity and characterized by macroscopic wettability were critically assessed. It was found that the wetting behavior cannot fully characterize the hydrodynamic slip because interface models that produced the same surface wettability yielded different values of the friction coefficient. Alternatively, the density depletion length, used to characterize the interfacial liquid structuring and the availability of momentum carriers (interfacial water molecules), was able to accurately represent the slip length trends independently of the interface model. These findings reassert the importance of physically sound interface models to study interfacial transport properties and the need of reliable parameters and characterization procedures to support theoretical models that seek to unveil the inconsistencies in hydrodynamic slip calculations.

In this contribution, we report on the nanoscale mechanisms responsible for enhancing the dielectric constant in the interfacial region of polymer-based nanocomposites. Recent experiments indicate ...

This study analyzes the effectivity of a freeze-dried additive formulated with inulin (I), Stevia (St), and ultrafiltered bovine plasma proteins (P) as a sugar substitute on the final properties of a sugar-free and low-fat muffins formulation. The following analysis were performed: shape factor, moisture loss, lamella thickness, final volume, aeration, pore size distribution and textural analysis. The addition of the binary combination 50%(P + St + I) + 50%(Sucralose) generated a synergistic effect: increasing the shape factor, final volume and aeration, and improving the pore size distribution and moisture loss. Given the success, the concentration of (P + St + I) was adjusted. A 12.5% concentration of (P + St + I) generated a hardness decrease during the studied period and did not exhibit statistical significant differences when compared to the control sample. Therefore this study demonstrated the effectiveness of the combination of Stevia, inulin, and bovine plasma proteins as sugar substitute.

β-phase gallium oxide (Ga

Heteroepitaxy of β-phase gallium oxide (β-Ga

In this investigation, the thermal transport across graphite–water interfaces was studied by means of nonequilibrium classical molecular dynamics (NEMD) simulations. The main focus of this work was...

A parametric optimization of a novel hybrid configuration of liquid-cooled heat sinks is presented herein. Such a hybrid design encompasses a combination of channels and microjets for optimal performance of chip scale high-power density electronic packages. Fractal flow channel geometries were used to create variants consisting of 16, 32, and 64 channels and a corresponding number of microjets in the impingement cavity. In addition to the conventional coplanar setup, where channels and area enhancing features align with the main flow direction, an out-of-plane network of channels was created to allow for removal of the cooling fluid in the opposite direction of the impinging jets. The parametric analysis was performed via 3-D CFD simulations to investigate the tradeoff between hydraulic and thermal resistances in jet cooling systems. The thermal resistance of the heat sinks was estimated and the pressure losses were calculated for every design. Observations of the flow patterns were used to inform on the optimization process of the architecture of the flow channels. A metric able to merge thermal and hydraulic performance was defined, such that the thermo-fluid characteristics of a liquid cooled heat sink are represented using one parameter. The utilization of this parameter led to a unique performance assessment of the proposed hybrid liquid-cooled heat sinks and allowed to identify an optimum design, which yields the lowest thermal resistance with minimum pumping power input.

Made available in DSpace on 2019-10-06T15:32:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-04-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Microsatellite loci were used to assess pollen contamination and mating patterns in an Eucalyptus urophylla seedling seed orchard (SO2) along with inbreeding and outbreeding depression in a second generation progeny test (PT2) established with SO2 seeds. We measured survival, diameter at breast height (DBH), and height (H) in SO2, PT2, and two other stands (SO1, PT) located at a distance of at least 210 m from SO2. Pollen contamination was substantial (11.9%), with the largest proportion coming from the closer SO1 stand (6.1%) than PT (4.7%) and 1.1% from unknown sources. The pollen dispersal pattern was isolation by distance but reached long distances (600 m). PT2 offspring were mainly the result of outcrossing (92.6%), but mating in SO2 was not random due to self-fertilization (7.4%), mating among relatives (6.6%), correlated mating (13.7%), and high male fertility success of trees with large DBH. Thus, families are a mixture of different levels of relatedness and some inbreeding (12.7%). Inbreeding depression was variable among traits; it was higher for selfing (39.6–49.5%) than mating among relatives (11.6–20.9%) and higher for mating between full-sibs (4.4%) than half-sibs (2.2%). Outbreeding depression was higher for pollen immigration from less improved sources (33.9–41.2%). Non-random mating resulted in a coancestry (0.152) higher than expected for half-sib families and an overestimation of heritability by 17.8%. Our results indicate that isolation distances greater than 600 m are necessary to avoid pollen contamination in Eucalyptus seed orchards. Furthermore, pollen immigration results in outbreeding depression, and selfing results in higher levels of inbreeding depression than mating among related trees. Universidade Estadual de São Paulo (UNESP/Ilha Solteira), Av. Brasil Centro, 56, CP 31, CEP 15385-000, Ilha Solteira Instituto Florestal de São Paulo (IF), CP 1322, CEP 01059-970 Universidade Estadual Paulista (UNESP/Botucatu), Rua José Barbosa de Barros, 1780, CEP 18.603-970 Instituto de Pesquisas e Estudos Florestais (IPEF), Via Comendador Pedro Morganti, 3500, CEP 13.415-000 Eldorado Brasil, Rodovia BR 158 – km 231, CEP 79.641-300 Suzano Papel e Celulose, Avenida Dr. José Lembo, 2215, CEP 18207-780 Universidade Estadual de São Paulo (UNESP/Ilha Solteira), Av. Brasil Centro, 56, CP 31, CEP 15385-000, Ilha Solteira Universidade Estadual Paulista (UNESP/Botucatu), Rua José Barbosa de Barros, 1780, CEP 18.603-970 FAPESP: 2014/03407-7

In this investigation, the thermal transport across 3C-type silicon carbide (SiC) and water interfaces was analyzed by means of nonequilibrium molecular dynamics (NEMD) simulations. To understand the details of the mechanisms involved in the transport of energy across hard-soft interfaces, spectral mapping methods were implemented. It was observed that the phonon density of states (DOS) at the interface is affected by the atomic surface termination, crystallographic plane, and the wetting conditions for both phases, indicating that different vibrational modes contribute to the interfacial heat transfer process based on the interface configuration. Low-frequency modes were found to contribute the most for the C- and Si-terminated SiC(1 0 0) planes and the C-terminated SiC(1 1 1) plane, while a noticeable contribution from high-frequency modes was observed for the Si-terminated SiC(1 1 1) plane. Out-of-plane modes significantly contributed to the heat transfer in all the analyzed surfaces, while the heat flux composition by in-plane modes was notably smaller, particularly for the SiC(1 1 1) plane. The in-plane modes lower contribution to the interfacial heat flux was related to the interfacial bonding strength and liquid structuring formed at the interface. An agreement was found between the thermal boundary conductance dependence on the DOS overlap and the interfacial liquid structure, while the interfacial bonding strength did not conclusively inform on the thermal transport behavior across these interfaces.

Submitted by DARLIN ULISES GONZALEZ ZARUMA (darlin.gonzalez@unesp.br) on 2020-05-22T05:13:52Z No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Submitted by DARLIN ULISES GONZALEZ ZARUMA (darlin.gonzalez@unesp.br) on 2020-05-22T05:13:52Z No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Approved for entry into archive by Ana Lucia de Grava Kempinas (algkempinas@fca.unesp.br) on 2020-05-22T12:10:05Z (GMT) No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Submitted by DARLIN ULISES GONZALEZ ZARUMA (darlin.gonzalez@unesp.br) on 2020-05-22T05:13:52Z No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Approved for entry into archive by Ana Lucia de Grava Kempinas (algkempinas@fca.unesp.br) on 2020-05-22T12:10:05Z (GMT) No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Submitted by DARLIN ULISES GONZALEZ ZARUMA (darlin.gonzalez@unesp.br) on 2020-05-22T05:13:52Z No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Made available in DSpace on 2020-05-22T12:10:05Z (GMT). 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No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Previous issue date: 2020-02-27 Submitted by DARLIN ULISES GONZALEZ ZARUMA (darlin.gonzalez@unesp.br) on 2020-05-22T05:13:52Z No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Approved for entry into archive by Ana Lucia de Grava Kempinas (algkempinas@fca.unesp.br) on 2020-05-22T12:10:05Z (GMT) No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Approved for entry into archive by Ana Lucia de Grava Kempinas (algkempinas@fca.unesp.br) on 2020-05-22T12:10:05Z (GMT) No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Made available in DSpace on 2020-05-22T12:10:05Z (GMT). No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Previous issue date: 2020-02-27 Approved for entry into archive by Ana Lucia de Grava Kempinas (algkempinas@fca.unesp.br) on 2020-05-22T12:10:05Z (GMT) No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Made available in DSpace on 2020-05-22T12:10:05Z (GMT). No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Previous issue date: 2020-02-27 Made available in DSpace on 2020-05-22T12:10:05Z (GMT). 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No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Previous issue date: 2020-02-27 Approved for entry into archive by Ana Lucia de Grava Kempinas (algkempinas@fca.unesp.br) on 2020-05-22T12:10:05Z (GMT) No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Approved for entry into archive by Ana Lucia de Grava Kempinas (algkempinas@fca.unesp.br) on 2020-05-22T12:10:05Z (GMT) No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Made available in DSpace on 2020-05-22T12:10:05Z (GMT). No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Previous issue date: 2020-02-27 Approved for entry into archive by Ana Lucia de Grava Kempinas (algkempinas@fca.unesp.br) on 2020-05-22T12:10:05Z (GMT) No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Made available in DSpace on 2020-05-22T12:10:05Z (GMT). No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Previous issue date: 2020-02-27 Approved for entry into archive by Ana Lucia de Grava Kempinas (algkempinas@fca.unesp.br) on 2020-05-22T12:10:05Z (GMT) No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Made available in DSpace on 2020-05-22T12:10:05Z (GMT). No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Previous issue date: 2020-02-27 Made available in DSpace on 2020-05-22T12:10:05Z (GMT). No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Previous issue date: 2020-02-27 Made available in DSpace on 2020-05-22T12:10:05Z (GMT). No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Previous issue date: 2020-02-27 Approved for entry into archive by Ana Lucia de Grava Kempinas (algkempinas@fca.unesp.br) on 2020-05-22T12:10:05Z (GMT) No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Made available in DSpace on 2020-05-22T12:10:05Z (GMT). No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Previous issue date: 2020-02-27 Approved for entry into archive by Ana Lucia de Grava Kempinas (algkempinas@fca.unesp.br) on 2020-05-22T12:10:05Z (GMT) No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Made available in DSpace on 2020-05-22T12:10:05Z (GMT). No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Previous issue date: 2020-02-27 Made available in DSpace on 2020-05-22T12:10:05Z (GMT). No. of bitstreams: 1 zaruma_dug_dr_botfca.pdf: 3109271 bytes, checksum: 47991aa6cd556e840b9b258fd666e992 (MD5) Previous issue date: 2020-02-27 Outra As espécies florestais possuem grande importância econômica, pois oferecem diversos produtos fundamentais para a sociedade, mas dada a impossibilidade de se separar ações de melhoramento das de conservação de recursos genéticos, técnicas como os testes combinados de progênies e procedências, tanto para espécies exóticas ou nativas, visam a seleção de árvores pelo valor genético e a transformação dos experimentos em PSM (pomares de semente por mudas). Os pomares de sementes são os vetores de produção de sementes de alta qualidade genética, que ligam as atividades de melhoramento das árvores às práticas de conservação. No anterior contexto, sementes de polinização aberta provenientes de uma população base de Eucalyptus camaldulensis e de um fragmento de Cerrado com Hymenaea stigonocarpa, foram coletadas e plantadas na Faculdade de Engenharia de Ilha Solteira (FEIS/UNESP), em Selvíria-MS. O objetivo deste trabalho foi verificar a variação genética e ganhos genéticos a partir do desbaste dentro de progênies de E. camaldulensis aos 10 anos de idade e estimar parâmetros genéticos populacionais, por meio de marcadores moleculares do tipo microssatélites para H. stigonocarpa, com vistas ao melhoramento genético e conservação, respectivamente. Para análise quantitativa, os caracteres altura (ALT), diâmetro a altura do peito (DAP), volume (VOL), densidade básica (DBM) e sobrevivência (SOB) foram utilizados. Assim os valores observados para sobrevivência (>90%) de E. camaldulensis indicam boa adaptação da espécie ao local e estimativas consideradas de alta magnitude para o coeficiente de variação genética aditiva individual, herdabilidade em nível de medias de progênies e acurácia. A estratégia de seleção dentro de progênies, com desbaste de 40% dos indivíduos com base no caráter DAP, revelou baixos ganhos com seleção. Em quanto H. stigonocarpa mostrou altos níveis de diversidade genética para adultos (54 alelos) e progênies (40 alelos), e uma estrutura genética espacial de até 75 m. o sistema de reprodução foi pôr cruzamento (0,99) entre parentes (0,125), resultando em um coeficiente de coancestria de 0,140, com progênies de meios-irmãos. Em conclusão, este estudo gerou informações sobre a variabilidade genética e permite orientar ações para transformá-los em pomares de sementes por mudas. Forest species are of great economic importance, as they offer several fundamental products for society, but given the impossibility of separating actions to improve those from the conservation of genetic resources, techniques such as the combined testing of progenies and provenances for both exotic and native species, aim at the selection of trees by their genetic value and the transformation of the experiments in PSM (seed orchards by seedlings). Seed orchards are the vectors of seed production of high genetic quality, which link tree improvement activities to conservation practices. In the previous context, open pollination seeds from a base population of Eucalyptus camaldulensis and a fragment of Cerrado with Hymenaea stigonocarpa, were collected and planted at the Faculty of Engineering of Ilha Solteira (FEIS/UNESP), in Selvíria-MS. The objective of this work was to evaluate the genetic variation and genetic gains from thinning within E. camaldulensis progeny at 10 years of age, and to estimate population genetic parameters, using microsatellite molecular markers for H. stigonocarpa, with a view to genetic improvement and conservation, respectively. For quantitative analysis, the characters height (H), diameter at breast height (DBH), volume (VOL), basic density (DBM) and survival (SUR) were used, thus the values observed for survival (> 90%) indicate good adaptation of the species to the place. Estimates considered to be of high magnitude were obtained for the coefficient of individual additive genetic variation, heritability of the mean of progenies and accuracy. The selection strategy within progenies, with thinning of 40% of the individuals based on the DAP character, revealed gains in the selection. High levels of genetic diversity for adults (54 alleles) and progenies (40 alleles) have been recorded, and a spatial genetic structure of up to 75 m. The average crossing rate was 0.99, indicating a breeding system for breeding the species. The crossing rate between relatives was 0.125, resulting in a coancestry coefficient of 0.140, with half-sib progenies. This study generated information on genetic variability and allows guiding actions to transform them into seed orchards for seedlings. Programa de becas SENESCYT - Convocatoria abierta - 2014 - Primeira fase: CIBAE-023-2014/ AR7L-000913-2016 - IFTH

Thin-film evaporation is relevant for electronics cooling, water desalination, and some energy conversion processes, and the overall performance of such applications relies on the adequate understanding of heating-induced phase-change mechanisms. Given the importance of polar compounds, such as alumina, for nanoporous membranes in water desalination, the effects of electrostatic forces on thin-film evaporation were investigated in this paper by means of molecular dynamics simulations. The influence of the electrostatic interactions was assessed by modelling the alumina-water interactions using two approaches: i) accounting for electrostatic and dispersive van der Waals (vdWs) forces between the solid and liquid atoms (LJ+Coulombic model), and ii) considering only dispersive vdWs interactions (LJ model). Additionally, a theoretical model based on the Schrage relationships was developed to compare theory and simulations. The results showed considerable differences in the evaporation rates obtained from the two interfacial models. For the LJ+Coulombic model, the liquid films were 40% thicker, and the maximum evaporation mass flux was lower than the LJ model by a factor of two. The theoretical Schrage relationships deviated from the simulation evaporation fluxes with errors of 2.2-18.1% and 24.0-57.9% for the LJ+Coulombic and LJ models, respectively. These observations suggest that the partial charges in the solid affect the evaporation behavior of water if the films are ∼5 nm or thinner. Moreover, the significant deviations in the evaporation behavior demonstrated the importance of a robust interfacial modelling approach to investigate thin-film evaporation in polar interfaces.

Thermal transport across interfaces made of 3C-type silicon carbide (SiC) and water was investigated by means of nonequilibrium classical molecular dynamics. The effects of different crystallographic planes and atomic surface terminations were studied, as it pertains to interfacial heat transfer. Hydrophilic and hydrophobic conditions were analyzed by modifying the interfacial bonding strength between the solid and liquid phases. The formation of structures in the liquid molecules close to the solid substrate was observed and found that such structures are sensitive to the uppermost atomic layer termination, the wettability condition, and the temperature of the system. It was found that the interfacial heat transfer and the wetting properties are not universally related and to obtain a more comprehensive description, it is required to include the structuring observed in the liquid phase at the interface. A reconciliation of the thermal boundary conductance calculations was found after the density depletion length was utilized as the descripting parameter.

Background Due to the nature of effective school food and nutrition education (SFNE) and the recent emphasis on it, FAO has developed a tool to assist member countries assess capacities, strengths, and gaps for developing and implementing successful SFNE programs at national and/or subnational level. Objective To describe the process used for applying FAO's SFNE Capacity Assessment Tool in El Salvador. Study Design, Setting, Participants A cross-sectional qualitative study conducted through the following 5 phases: 1) setting up an FAO's facilitation team; 2) a SFNE stakeholder mapping (n = 15, from government/NGOs staff to teachers and families); 3) background research of national secondary data, policies, reports, and materials relevant to SFNE; 4) interviews with key actors (n = 7) and facilitation of multi-stakeholder consultative workshops (n = 5); and 5) report and follow-up. Measurable Outcome/Analysis The tool comprises a series of guiding questions to assess individual SFNE capacities, as well as organizational capacity and the policy environment. Key variables of interest comprised policy frameworks, political commitment, program-related capacities, school system, individual training schemes, among others. Descriptive content analysis was carried out to synthesize the results from each dimension. Results Main capacity gaps identified were: weak institutional coherence, exclusion of SFNE in the formal school curriculum, lack of opportunities to engage all school-level stakeholders in learning activities, and insufficient educational materials for all schools. Key strengths focused on the inclusion of SFNE into key policies, and the availability of SFNE training schemes for front-line educators. Prioritized proposed solutions centered around advocacy for the allocation of SFNE-specific government budget, leveraging on existing multisector platforms to enhance institutional coherence, and strengthening of training of curriculum developers. Conclusion The application of the tool evidenced key SFNE capacity gaps that needed to be addressed at national level, and provided a clear and nationally-endorsed roadmap to enhance the impact of SFNE in El Salvador.

La terapia de luz de bajo nivel (LLLT; Por sus siglas en inglés) y la terapia fotodinámica (PDT; Por sus siglas en inglés) son dos técnicas biofotónicas que ofrecen una solución alternativa de bajo costo y con mínimos o nulos efectos secundarios a problemas médicos como lo son las heridas crónicas. En el presente estudio se evaluó a la LLLT y a la PDT en la mejora del proceso de cicatrización de heridas cutáneas. La PDT involucra la activación de un colorante fotosensibilizador con una longitud de onda específica. Los fotosensibilizadores (FSs) utilizados fueron azul de metileno (AM) y rosa de bengala (RB), los cuales fueron activados a 633 nm (luz roja) y 532 nm (luz verde) respectivamente. La densidad de energía empleada en la activación de los FSs fue de 10 J/cm^2. Esta misma densidad de energía (10 J/cm^2) fue utilizada como dosis de luz para la LLLT en longitudes de onda dentro del espectro del azul, verde y rojo; Además se analizó el efecto de la LLLT en una terapia que combina las tres longitudes de onda (10 J/cm^2 de luz azul, 10 J/cm^2 de luz verde y 10 J/cm^2 de luz roja). El trabajo se realizó con un total de 35 ratas alopécicas (Rattus orvegicus) divididas aleatoriamente en 7 grupos experimentales: i) Control, ii) LLLT R, iii) LLLT V, iv) LLLT A, v) LLLT RVA, vi) PDT-AM y vii) PDT-RB. Para todos los animales de cada grupo, se realizaron 2 heridas circulares (1 cm de diámetro) en el dorso. Posteriormente, se realizó el tratamiento respectivo en cada herida a los días 0, 1, y 2 y se monitoreó el proceso de cicatrización mediante fotografías diarias hasta el día 21. Para estudiar los cambios histológicos provocados en el tejido epitelial se sacrificaron periódicamente los animales de experimentación correspondientes (días 3, 5, 7, 14 y 21) y se realizaron biopsias sobre la región de las heridas, las cuales fueron procesadas y evaluadas mediante cortes histológicos y tinción hematoxilina y eosina (HE). Los resultados demuestran que ambos tipos de tratamiento (LLLT y PDT) tuvieron un efecto beneficioso sobre el proceso de cicatrización, especialmente se observó un proceso de reepitelización mejorado que al de los controles. La LLLT roja y la LLLT con azul, verde y rojo, mostraron una buena separación y reestructuración de las capas epiteliales, la LLLT verde, en especial la LLLT azul promovieron principalmente la formación de la epidermis, de igual manera que la PDT verde con RB en donde se observó una exagerada respuesta en la formación de la capa

The heat transfer performance of liquid-cooled heat sinks with a constructal design of the flow field configurations is assessed in the present investigation. Y- and Ψ-shaped microfluidic networks embedded on a silicon substrate are numerically analyzed and compared in order to propose an alternative cooling layer for integrated circuits (ICs). The shape, path and geometric dimensions of the flow channels are designed with the Phi number and Allometric scaling laws based on constructal networks, resulting in tree-shaped flow paths with variable hydraulic diameter. The thermal and hydraulic performances of eight different configurations are discussed in terms of the average surface temperature and pressure drop, respectively. Results indicate that the Ψ-shaped heat sink designs offer a higher degree of temperature uniformity than Y-shaped designs, with the penalty of a slightly higher flow restriction. It was observed that the Phi number ratio has a strong effect on thermal performance, with enhanced results for higher ratios. Discussions about heat transfer area, temperature uniformity and pressure drop are given for the different cases, proposing an enhanced design for electronics cooling applications.

Made available in DSpace on 2018-11-12T17:28:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-12-01. Added 1 bitstream(s) on 2021-07-14T17:52:01Z : No. of bitstreams: 1 S2236-89062015000400641.pdf: 1267005 bytes, checksum: 03ef2c50bdb049ac0808bbcb17b5c6ab (MD5) Atualmente a vegetação natural do Cerrado encontra-se altamente fragmentada, causando a perda da variabilidade genética e, concomitantemente, risco de extinção das populações remanescentes nestes fragmentos. Não indiferente a isto, o objetivo desse trabalho foi estimar a variabilidade genética de um teste de progênies de Dipteryx alata, formado a partir do material da Estação Ecológica de Paulo de Faria, para efetivar a conservação genética do que ainda resta da espécie no Estado de São Paulo e subsidiar um método de seleção visando a formação de pomar de sementes com qualidade genética para serem empregadas na restauração do Cerrado. O teste de progênies, composto por 59 progênies, 17 repetições e uma planta por parcela, foi instalado no dia 10 de julho de 2013, na Fazenda de Ensino, Pesquisa e Extensão (FEPE) da Universidade Estadual Paulista, Ilha Solteira, SP, Brasil. As estimativas dos parâmetros genéticos foram baseadas na altura total de plantas com 3, 7 e 21 meses de idade. As estimativas de herdabilidade média, coeficiente de variação genética individual, acurácia (0,81, 39,88 e 0,90, respectivamente, aos três meses) e correlações genéticas entre ALT e DMC (0,74) indicaram que a formação do teste de progênies permitiu resgatar o material genético com variabilidade genética suficiente para garantir a formação de novas populações e as estimativas dos parâmetros genéticos apresentaram base genética promissora, o que permite ganhos na seleção em programas de melhoramento e a formação de pomar de sementes para utilização em programas de restauração. ABSTRACT Currently, the natural vegetation of the Cerrado is highly fragmented, causing the loss of genetic variability and concomitant risk of extinction of the remaining populations in these fragments. Not indifferent to this, the aim of this study was to estimate the genetic variability of a progeny test of Dipteryx alata, formed from the material of Estação Ecológica Paulo de Faria, to effect the genetic conservation of what remains of the species in the State of São Paulo and subsidize a selection method aimed the formation of a seed orchard with genetic quality to be used in the Cerrado restoration. The progeny test, with 59 progenies, 17 replications and a plant per plot, was installed on July 10, 2013, in the Fazenda de Pesquisa, Ensino e Extensão (FEPE) of Universidade Estadual Paulista, Ilha Solteira, SP, Brazil. The genetic parameter estimates were based on total plant height of 3, 7, and 21 months of age. Estimates of average heritability, individual genetic variation coefficient, accuracy (0.81, 39.88, and 0.90, respectively, at three months), and genetic correlations between ALT and DMC (0.74) indicated that the formation of the test progenies allowed to rescue the genetic material with enough genetic variability to ensure the formation of new populations and estimates of genetic parameters showed promising genetic basis, which allows gains in selection in breeding programs and seed orchard formation for use in restoration programs. Universidade Estadual Paulista Faculdade de Engenharia de Ilha Solteira Universidade Estadual Paulista Faculdade de Ciências Agronômicas Instituto Florestal Universidade Estadual Paulista Faculdade de Engenharia de Ilha Solteira Universidade Estadual Paulista Faculdade de Ciências Agronômicas

An experimental characterization of hybrid water-cooled heat sinks for multi-core CPUs was conducted. The hybrid heat sinks consist of a water block containing fractal channel manifolds ending in an array of jet nozzles attached to a copper plate. Advanced additive manufacturing techniques were required for the fabrication of the heat sinks due to the manifolds complexity. The effects of the jet nozzles number and distribution, depth of the flood chamber, and surface enhancing features were investigated in terms of hydraulic and thermal performance. A minimum pressure drop variation was observed for different number of jet nozzles (16, 32, and 64 jets), which is consistent with previous simulation results. Alternatively, the pressure drop associated with a 3-mm size reduction of the flood chamber generated a two-fold increase in the pressure drop difference, but under 5% of the total pressure drop. A sharp temperature increase (~30 °C) was observed from idle operation within 10 s after applying a full load on the CPU and the system reached steady state in ~74 s. The highest core temperature was observed using the heat sink with 32 jets, while the heat sinks with 16 and 64 jets had similar thermal performance. Area enhancing features added to the copper plate produced negligible effects on the hydraulic performance, while average core temperature reductions up to 3 °C were measured using circular pin fins. To further analyze the thermo-hydraulic performance, the thermal resistance and the pumping power were calculated. The overall performance assessment was conducted using a metric formed by the combination of the thermal resistance and pumping power. This metric helped to identify the best heat sink based on the thermo-fluid characteristics, i.e., the lowest core temperature with the least pumping power.

The RNA-guided Cas9 nuclease, from the type II prokaryotic clustered regularly interspersed short palindromic repeats (CRISPR) adaptive immune system, has been adapted by scientists to enable site specific genome editing of eukaryotic cells both in vitro and in vivo. Previously, we reported the development of an adeno-associated virus (AAV)-mediated CRISPR Streptococcus pyogenes (Sp) Cas9 system, in which the genome editing function can be regulated by controlling the expression of the guide RNA (sgRNA) in a doxycycline (Dox)-dependent manner. Here, we report the development of an AAV vector tool kit utilizing the Cas9 from Staphylococcus aureus (SaCas9). We demonstrate in vitro genome editing in human derived 293FT cells and mouse derived Neuro2A (N2A) cells and in vivo in neurons of the mouse brain. We also demonstrate the ability to regulate the induction of genome editing temporally with Dox and spatially with Cre-recombinase. The combination of these systems enables AAV-mediated CRISPR/Cas9 genome editing to be regulated both spatially and temporally.

The development of micro and nanoscale devices spans a wide range of purposes and the presence of solid-liquid interfaces is observed in several applications, especially in the biomedical field. The interfacial solid-liquid interactions are short-ranged and dominant in a region 1.0–1.5 nm thick adjacent to the interface, where the liquid particles tend to form organized complex structures. The existence of interfacial liquid structuring has demonstrated to influence heat transfer across solid-liquid interfaces. In this investigation, silicon carbide (SiC) was considered due to its promising properties, such as high electron mobility, high saturation drift velocity, and biocompatibility. The structural properties of water films were studied numerically by means of Molecular Dynamics (MD) simulations. It was observed that energy potential wells generated by the solid phase prompted the formation of periodic concentration regions in the first hydration layer adjacent to the solid. In high-temperature systems, the mobility of the liquid atoms increased; however, the periodic structures formed at the interface remained observable. Structural parameters, such as the structure factor and radial distribution function suggested a water interfacial structure between ice and liquid, but the vibrational behavior did not implicate the same conclusion.

One of the determinant factors in the success of breeding pro­grams that aim to select genotypes for different geographical regions is understanding the interaction between genotypes and environments (GxE). The objectives of this study were to evaluate GxE interaction, stability, and adaptability, and deter­mine the need for environmental stratification of open pollina­ted progenies of Eucalyptus urophylla. Five progeny tests were established in study areas with different environmental condi­tions in southeast and mid-west Brazil. We used a complete randomized block experimental design with 138 to 167 proge­nies, and variations in the numbers of replicates and plants per plot. The trait measured was diameter at breast height (DBH) at two years of age and the AMMI method was used to determine patterns of GxE interaction. Significant effects were detected for genotypes, environments, and for GxE interaction. The effect of environment was responsible for the greatest propor­tion of the phenotypic variation, followed by the effect of genotypes and GxE interaction. Some progenies with greater productivity and stability were identified, although stability is not associated with productivity. The stratification of the selec­tion in three specific environments is necessary due to the occurrence of a complex GxE interaction.

UNESP-Universidade Estadual Paulista Julio de Mesquita Filho FEIS-Faculdade de Engenharia de Ilha Solteira, Avenida Brasil, n. 56-Centro

The new generation of integrated-circuit chips demands novel cooling techniques for enhancing device performance. Air-cooling techniques are not sufficient anymore to reach the necessary dissipation for these devices while liquid-cooling techniques have proved to be an efficient solution. The addition of nanoparticles to conventional cooling fluid changes its thermo-physical properties based on the type of the particle material, base fluid, particle volume fraction and size, pumping power, etc. The present study proposes a flow field pattern for a nanofluid-cooled heat sink in order to improve the heat transfer and the flow distribution based on a new design. Al2O3 - water nanofluid is the working fluid. The results show the comparison between the simple conventional use of water and the use of a nanofluid, by way of implementing critical factors for performance evaluation: thermal resistance, temperature uniformity, highest base temperature, and pressure drop. The analysis enables to determine that the heat sink thermal performance is definitely improved by the use of a nanofluid.

In this paper we discuss how Finite Element Analysis (FEA) can be used to simulate Micro Electro Mechanical Systems (MEMS). The mechanical behavior of many MEMS devices is a direct result of non-mechanical physical phenomena, such as electrostatics, electromagnetics or heat transfer. This coupling of mechanical behavior with another physical effect, combined with considerations associated with their small dimensions, poses significant challenges to the analysis of MEMS. These challenges can be met by FEA software capable of performing multiphysics analysis with no limitations on the dimensions of the objects in a model. With such software at their disposal, engineers can use the results of their simulations to design MEMS devices.

The understanding of nanoscale heat transfer across solid-liquid interfaces poses similar challenges as solid-solid interfaces; however, the higher mobility of liquid particles increases the complexity of this problem. It has been observed that liquid particles tend to form organized structures in the vicinity of solid surfaces; additionally, the formation of such structures has been reported to correlate with heat transfer across interfaces. Classical molecular dynamics simulations were used to investigate the behavior of liquid water in contact with crystalline and amorphous silicon. The in-plane and out-of-plane structure of interfacial water was characterized under different artificial wettability conditions, i.e., the silicon-water interaction potentials were calibrated to reproduce a wide range of wettability conditions. The change in the vibrational density of states was analyzed in order to quantify the mismatch between modes on both sides of the solid-liquid interfaces. Linear response theory was used to calculate the thermal boundary conductance at the different interfaces and a correlation was found between surface chemistry and heat transfer.