Analyzing Impacts of Interfacial Instabilities on the Sweeping Power of Newtonian Fluids to Immiscibly Displace Power-Law Materials

Injection of Newtonian fluids to displace pseudoplastic and dilatant fluids, governed by the power-law viscosity relationship, is common in many industrial processes. In these applications, changing the viscosity of the displaced fluid through velocity alteration can regulate interfacial instabilities, displacement efficiency, the thickness of the static wall layer, and the injected fluid’s tendency to move toward particular parts of the channel. The dynamic behavior of the fluid–fluid interface in the case of immiscibility is highly complicated and complex. In this study, a code was developed that utilizes a multi-component model of the lattice Boltzmann method to decrease the computational cost and accurately model these problems. Accordingly, a 2D inclined channel, filled with a stagnant incompressible Newtonian fluid in the initial section followed by a power-law material, was modeled for numerous scenarios. In conclusion, the results indicate that reducing the power-law index can regulate interfacial instabilities leading to dynamic deformation of static wall layers at the top and the bottom of the channel. However, it does not guarantee a reduction in the thickness of these layers, which is crucial to improve displacement efficiency. The impacts of the compatibility factor and power-law index variations on the filling pattern and finger structure were intensively evaluated.

Meta-Motivation and the Big Five Personality Factors

The present study aims to identify the five major factors of personality and their relationship to meta-motivation among university students. The two researchers used the correlational descriptive approach, and the study population consisted of 5260 male and female students pursuing a bachelor's degree from Palestine Technical University. The two researchers chose the sample by a simple random method, which consisted of 377 students split between 133 males and 244 females. The results showed that the extraversion factor, one of the five major personality factors, is the most prevalent factor among students of Palestine Technical University, whereas the neurotic factor is the least prevalent factor. They also showed a direct correlation between the five major factors (extraversion, openness, conscientiousness and all dimensions of meta-motivation), the existence of an inverse correlation between the neurotic factor and all dimensions of meta-motivation and the absence of a correlation between the compatibility factor and all dimensions of meta-motivation. The study recommends conducting field studies to enhance meta-motivation among university students while depending on the five major personality factors and forming the ideal personality for a university student.

Achieving High Thermoelectric Performance in Rare-Earth Element-Free CaMg2Bi2 with High Carrier Mobility and Ultralow Lattice Thermal Conductivity

CaMg2Bi2-based compounds, a kind of the representative compounds of Zintl phases, have uniquely inherent layered structure and hence are considered to be potential thermoelectric materials. Generally, alloying is a traditional and effective way to reduce the lattice thermal conductivity through the mass and strain field fluctuation between host and guest atoms. The cation sites have very few contributions to the band structure around the fermi level; thus, cation substitution may have negligible influence on the electric transport properties. What is more, widespread application of thermoelectric materials not only desires high ZT value but also calls for low-cost and environmentally benign constituent elements. Here, Ba substitution on cation site achieves a sharp reduction in lattice thermal conductivity through enhanced point defects scattering without the obvious sacrifice of high carrier mobility, and thus improves thermoelectric properties. Then, by combining further enhanced phonon scattering caused by isoelectronic substitution of Zn on the Mg site, an extraordinarily low lattice thermal conductivity of 0.51 W m-1 K-1 at 873 K is achieved in (Ca0.75Ba0.25)0.995Na0.005Mg1.95Zn0.05Bi1.98 alloy, approaching the amorphous limit. Such maintenance of high mobility and realization of ultralow lattice thermal conductivity synergistically result in broadly improvement of the quality factor β. Finally, a maximum ZT of 1.25 at 873 K and the corresponding ZTave up to 0.85 from 300 K to 873 K have been obtained for the same composition, meanwhile possessing temperature independent compatibility factor. To our knowledge, the current ZTave exceeds all the reported values in AMg2Bi2-based compounds so far. Furthermore, the low-cost and environment-friendly characteristic plus excellent thermoelectric performance also make the present Zintl phase CaMg2Bi2 more competitive in practical application.

Expression of Brassica napus GLO1 is sufficient to breakdown artificial self-incompatibility in Arabidopsis thaliana

Members of the Brassicaceae family have the ability to regulate pollination events occurring on the stigma surface. In Brassica species, self-pollination leads to an allele specific interaction between the pollen small cysteine-rich peptide ligand (SCR/SP11) and the stigmatic S-receptor kinase (SRK) that activates the E3 ubiquitin ligase ARC1 (Armadillo repeat-containing 1), resulting in proteasomal degradation of various compatibility factors including Glyoxalase I (GLO1) which is necessary for successful pollination. Suppression of GLO1 was sufficient to reduce compatibility, and overexpression of GLO1 in self-incompatible Brassica napus stigmas resulted in partial breakdown of the self-incompatibility response. Here, we verified if BnGLO1 could function as a compatibility factor in the artificial self-incompatibility system of Arabidopsis thaliana expressing AlSCRb, AlSRKb and AlARC1 proteins from A. lyrata. Overexpression of BnGLO1 is sufficient to breakdown self-incompatibility response in A. thaliana stigmas, suggesting that GLO1 functions as an inter-species compatibility factor. Therefore, GLO1 has an indisputable role as a compatibility factor in the stigma in regulating pollen attachment and pollen tube growth. Lastly, this study demonstrates the usefulness of an artificial self-incompatibility system in A. thaliana for interspecific self-incompatibility studies.

Stigma Receptivity is controlled by Functionally Redundant MAPK Pathway Components in Arabidopsis

SummaryIn angiosperms, the process of pollination relies on species-specific interaction and signaling between the male (pollen) and female (pistil) counterparts where the interplay between several pollen and stigma proteins decides the fate of the pollen. In Brassicaceae, the dry stigmatic papillary cells control pollen germination by releasing resources only to compatible pollen thereby allowing pollen to hydrate and germinate. Despite the identification of a number of stigmatic proteins that facilitate pollination responses, the signaling mechanisms that regulate functions of these proteins have remained unknown. Here we show that, in Arabidopsis, an extremely functionally redundant mitogen-activated protein kinase (MAPK) cascade is required for maintaining stigma receptivity to accept compatible pollen. Our genetic analyses demonstrate that in stigmas, five MAPK kinases (MKKs), MKK1/2/3/7/9 are required to transmit upstream signals to two MPKs, MPK3/4, to mediate compatible pollination. Compromised functions of these five MKKs in the quintuple mutant (mkk1/2/3RNAi/mkk7/9) phenocopied pollination defects observed in the mpk4RNAi/mpk3 double mutant. We further show that this MAPK nexus converges on Exo70A1, a previously identified stigmatic compatibility factor essential for pollination. Given that pollination is the crucial initial step during plant reproduction, understanding the mechanisms that govern successful pollination could lead to development of strategies to improve crop yield.

Modelling a Segmented Skutterudite-Based Thermoelectric Generator to Achieve Maximum Conversion Efficiency

Thermoelectric generator (TEG) modules generally have a low conversion efficiency. Among the reasons for the lower conversion efficiency is thermoelectric (TE) material mismatch. Hence, it is imperative to carefully select the TE material and optimize the design before any mass-scale production of the modules. Here, with the help of Comsol-Multiphysics (5.3) software, TE materials were carefully selected and the design was optimized to achieve a higher conversion efficiency. An initial module simulation (32 couples) of unsegmented skutterudite Ba0.1Yb0.2Fe0.1Co3.9Sb12 (n-type) and Ce0.5Yb0.5Fe3.25Co0.75Sb12 (p-type) TE materials was carried out. At the temperature gradient T∆ = 500 K, a maximum simulated conversion efficiency of 9.2% and a calculated efficiency of 10% were obtained. In optimization via segmentation, the selection of TE materials, considering compatibility factor (s) and ZT, was carefully done. On the cold side, Bi2Te3 (n-type) and Sb2Te3 (p-type) TE materials were added as part of the segmentation, and at the same temperature gradient, an open circuit voltage of 6.2 V matched a load output power of 45 W, and a maximum simulated conversion efficiency of 15.7% and a calculated efficiency of 17.2% were achieved. A significant increase in the output characteristics of the module shows that the segmentation is effective. The TEG shows promising output characteristics.