thermal dissipation
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Electronics ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 236
Takayuki Ohba ◽  
Koji Sakui ◽  
Shinji Sugatani ◽  
Hiroyuki Ryoson ◽  
Norio Chujo

Bumpless Build Cube (BBCube) using Wafer-on-Wafer (WOW) and Chip-on-Wafer (COW) for Tera-Scale Three-Dimensional Integration (3DI) is discussed. Bumpless interconnects between wafers and between chips and wafers are a second-generation alternative to the use of micro-bumps for WOW and COW technologies. WOW and COW technologies for BBCube can be used for homogeneous and heterogeneous 3DI, respectively. Ultra-thinning of wafers down to 4 μm offers the advantage of a small form factor, not only in terms of the total volume of 3D ICs, but also the aspect ratio of Through-Silicon-Vias (TSVs). Bumpless interconnect technology can increase the number of TSVs per chip due to the finer TSV pitch and the lower impedance of bumpless TSV interconnects. In addition, high-density TSV interconnects with a short length provide the highest thermal dissipation from high-temperature devices such as CPUs and GPUs. This paper describes the process platform for BBCube WOW and COW technologies and BBCube DRAMs with high speed and low IO buffer power by enhancing parallelism and increasing yield by using a vertically replaceable memory block architecture, and also presents a comparison of thermal characteristics in 3D structures constructed with micro-bumps and BBCube.

Juan de Dios Unión-Sánchez ◽  
Manuel Jesús Hermoso-Orzáez ◽  
Manuel Jesús Hervás-Pulido ◽  
Blas Ogáyar-Fernández

Currently, LED technology is an established form of lighting in our cities and homes. Its lighting performance, durability, energy efficiency and light, together with the economic savings that its use implies, are displacing other classic forms of lighting. However, some problems associated with the durability of the equipment related to the problems of thermal dissipation and high temperature have begun to be detected, which end up affecting their luminous intensity and the useful life. There are many studies that show a direct relationship between the low quality of LED lighting and the aging of the equipment or its overheating, observing the depreciation of the intensity of the light and the visual chromaticity performance that can affect the health of users by altering circadian rhythms. On the other hand, the shortened useful life of the luminaires due to thermal stress has a direct impact on the LCA (Life Cycle Analysis) and its environmental impact, which indirectly affects human health. The purpose of this article is to compare the results previously obtained, at different contour temperatures, by theoretical thermal simulation of the 3D model of LED street lighting luminaires through the ANSYS Fluent simulation software. Contrasting these results with the practical results obtained with a thermal imaging camera, the study shows how the phenomenon of thermal dissipation plays a fundamental role in the lighting performance of LED technology. The parameter studied in this work is junction temperature (Tj), and how it can be used to predict the luminous properties in the design phase of luminaires in order to increase their useful life.

2022 ◽  
Dong Wang ◽  
Dingyao Liu ◽  
JianHua Xu ◽  
JiaJun Fu ◽  
Kai Wu

It is still a formidable challenge to develop ideal thermal dissipation materials with simultaneous high thermal conductivity, excellent mechanical softness and toughness, and spontaneous self-healing. Herein, we report the introduction...

2021 ◽  
Thales Caetano Oliveira ◽  
Juliana Silva Rodrigues Cabral ◽  
Leticia Rezende Santana ◽  
Germanna Gouveia Tavares ◽  
Luan Dionísio Silva Santos ◽  

Abstract Soybean (Glycine max L.) is an economically important crop worldwide. However, increasingly long periods of drought have reduced the productivity of this crop. Studies have shown that inoculation with arbuscular mycorrhizal fungi (AMF) provides a potential alternative strategy for mitigating drought. In the present study, we measured the physiological and morphological performance of two soybean cultivars under drought in symbiosis with Rhizophagus clarus. Soybean plants Anta82 and Desafio, were grown in pots previously inoculated with R. clarus. Water deficit (WD) was imposed at the V3 development stage and maintained for 7 days. A control group was performed in parallel with well-irrigated plants in the absence of R. clarus in a greenhouse. Three and seven days after the WD imposition the analysis were performed. Cultivar Anta82 showed a higher percentage of colonization, N and K leaf content, whereas Desafio, showed higher water potential, water-use efficiency under WD, and thermal dissipation that allowed higher values for Fv/Fm, A, and PH under WD+AMF. The Principal Components Analysis results were able to demonstrate that both cultivars in water deficit with AMF colonization clustered together with well-watered plants. These findings suggest that AMF had an effect on plants in order to reduce drought physiological impairment.

Dongjuan Niu ◽  
Huiru Wu

In this article, we study the global well-posedness and large-time behaviors of solutions to the two-dimensional tropical climate system with zero thermal diffusion for a small initial data in the whole space. The main approaches include high and low frequency decomposition method and exploiting the structure of system (1) to obtain the estimates of thermal dissipation. We utilize the time decay properties of the kernels to a linear differential equation to obtain the decay rates of solutions of the low frequency part and the decay property of exponential operator for the high frequency part. The key ingredient here is the explicit large-time decay rate of solutions.

2021 ◽  
Vol 118 (51) ◽  
pp. e2114952118
Yuichi Yokochi ◽  
Yuka Fukushi ◽  
Ken-ichi Wakabayashi ◽  
Keisuke Yoshida ◽  
Toru Hisabori

Thioredoxin (Trx) is a protein that mediates the reducing power transfer from the photosynthetic electron transport system to target enzymes in chloroplasts and regulates their activities. Redox regulation governed by Trx is a system that is central to the adaptation of various chloroplast functions to the ever-changing light environment. However, the factors involved in the opposite reaction (i.e., the oxidation of various enzymes) have yet to be revealed. Recently, it has been suggested that Trx and Trx-like proteins could oxidize Trx-targeted proteins in vitro. To elucidate the in vivo function of these proteins as oxidation factors, we generated mutant plant lines deficient in Trx or Trx-like proteins and studied how the proteins are involved in oxidative regulation in chloroplasts. We found that f-type Trx and two types of Trx-like proteins, Trx-like 2 and atypical Cys His-rich Trx (ACHT), seemed to serve as oxidation factors for Trx-targeted proteins, such as fructose-1,6-bisphosphatase, Rubisco activase, and the γ-subunit of ATP synthase. In addition, ACHT was found to be involved in regulating nonphotochemical quenching, which is the mechanism underlying the thermal dissipation of excess light energy. Overall, these results indicate that Trx and Trx-like proteins regulate chloroplast functions in concert by controlling the redox state of various photosynthesis-related proteins in vivo.

2021 ◽  
Vol 12 ◽  
Gaia Pasqualotto ◽  
Vinicio Carraro ◽  
Eloy Suarez Huerta ◽  
Tommaso Anfodillo

A remarkable increase in vapor pressure deficit (VPD) has been recorded in the last decades in relation to global warming. Higher VPD generally leads to stomatal closure and limitations to leaf carbon uptake. Assessing tree conductance responses to VPD is a key step for modeling plant performances and productivity under future environmental conditions, especially when trees are cultivated well outside their native range as for hazelnut (Corylus spp.). Our main aim is to assess the stand-level surface canopy conductance (Gsurf) responses to VPD in hazelnut across different continents to provide a proxy for potential productivity. Tree sap flow (Fd) was measured by Thermal dissipation probes (TDP) probes (six per sites) in eight hazelnut orchards in France, Italy, Georgia, Australia, and Chile during three growing seasons since 2016, together with the main meteorological parameters. We extracted diurnal Fd to estimate the canopy conductance Gsurf.. In all the sites, the maximum Gsurf occurred at low values of VPD (on average 0.57 kPa) showing that hazelnut promptly avoids leaf dehydration and that maximum leaf gas exchange is limited at relatively low VPD (i.e., often less than 1 kPa). The sensitivity of the conductance vs. VPD (i.e., -dG/dlnVPD) resulted much lower (average m = −0.36) compared to other tree species, with little differences among sites. We identified a range of suboptimal VPD conditions for Gsurf maximization (Gsurf > 80% compared to maximum) in each site, named “VPD80,” which multiplied by the mean Gsurf might be used as a proxy for assessing the maximum gas exchange of the orchard with a specific management and site. Potential gas exchange appeared relatively constant in most of the sites except in France (much higher) and in the driest Australian site (much lower). This study assessed the sensitivity of hazelnut to VPD and proposed a simple proxy for predicting the potential gas exchange in different areas. Our results can be used for defining suitability maps based on average VPD conditions, thus facilitating correct identification of the potentially most productive sites.

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1523
Haroon Ur Rasheed ◽  
Saeed Islam ◽  
Maha M. Helmi ◽  
Sam Alsallami ◽  
Zeeshan Khan ◽  

This research investigates the influence of the combined effect of the chemically reactive and thermal radiation on electrically conductive stagnation point flow of nanofluid flow in the presence of a stationary magnetic field. Furthermore, the effect of Newtonian heating, thermal dissipation, and activation energy are considered. The boundary layer theory developed the constitutive partial differential momentum, energy, and diffusion balance equations. The fundamental flow model is changed to a system of coupled ordinary differential equations (ODEs) via proper transformations. These nonlinear-coupled equations are addressed analytically by implementing an efficient analytical method, in which a Mathematica 11.0 programming code is developed for numerical simulation. For optimizing system accuracy, stability and convergence analyses are carried out. The consequences of dimensionless parameters on flow fields are investigated to gain insight into the physical parameters. The result of these physical constraints on momentum and thermal boundary layers, along with concentration profiles, are discussed and demonstrated via plotted graphs. The computational outcomes of skin friction coefficient, mass, and heat transfer rate under the influence of appropriate parameters are demonstrated graphically.

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