Adaptive Honeycomb Based on Additive Manufacturing: Research on Rapid Generation Algorithm, Manufacturing Process, and Mechanical Characteristics

In order to solve the problems of low efficiency and complex process in the current generation algorithm and process verification of hexagonal honeycomb structures for complex spatial shapes and arbitrarily curved surfaces, this paper proposes an adaptive hexagonal grid calculation method based on the intracellular splitting iteration method for the first time. This method can better adapt to the complex spatial shape and arbitrary curved surface structure in the three-dimensional space, and it can also achieve the purpose of enhancing the mechanical performance while maintaining the lightweight structure. According to the principle of the above algorithm, different structural models including honeycomb cells are calculated and generated. 316L Stainless Steel material and Selective Laser Melting additive manufacturing processes are also used for printing actual samples. The printed samples are mechanically compressed. According to the results of the compression curve, the critical yield force of the honeycomb grid parts with iteration is higher than that of the homogeneous honeycomb grid parts, and the value is basically greater than 30%-40%. Finally, the energy absorption efficiency can be increased by more than 20% according to the compression characteristics of the adaptive iterative honeycomb analyzed.

Harnessing Synergistic Biostimulatory Processes: A Plausible Approach for Enhanced Crop Growth and Resilience in Organic Farming

Demand for organically grown food crops is rising substantially annually owing to their contributions to human health. However, organic farm production is still generally lower compared to conventional farming. Nutrient availability, content consistency, uptake, assimilation, and crop responses to various stresses were reported as critical yield-limiting factors in many organic farming systems. In recent years, plant biostimulants (BSs) have gained much interest from researchers and growers, and with the objective of integrating these products to enhance nutrient use efficiency (NUE), crop performance, and delivering better stress resilience in organic-related farming. This review gave an overview of direct and indirect mechanisms of microbial and non-microbial BSs in enhancing plant nutrient uptake, physiological status, productivity, resilience to various stressors, and soil-microbe-plant interactions. BSs offer a promising, innovative and sustainable strategy to supplement and replace agrochemicals in the near future. With greater mechanistic clarity, designing purposeful combinations of microbial and non-microbial BSs that would interact synergistically and deliver desired outcomes in terms of acceptable yield and high-quality products sustainably will be pivotal. Understanding these mechanisms will improve the next generation of novel and well-characterized BSs, combining microbial and non-microbial BSs strategically with specific desired synergistic bio-stimulatory action, to deliver enhanced plant growth, yield, quality, and resilience consistently in organic-related cultivation.

Clouds of bubbles in a viscoplastic fluid

Viscoplastic fluids can hold bubbles/particles stationary by balancing the buoyancy stress with the yield stress – the key parameter here is the yield number $Y$ , the ratio of the yield stress to the buoyancy stress. In the present study, we investigate a suspension of bubbles in a yield-stress fluid. More precisely, we compute how much is the gas fraction $\phi$ that could be held trapped in a yield-stress fluid without motion. Here the goal is to shed light on how the bubbles feel their neighbours through the stress field and to compute the critical yield number for a bubble cloud beyond which the flow is suppressed. We perform two-dimensional computations in a full periodic box with randomized positions of the monosized circular bubbles. A large number of configurations are investigated to obtain statistically converged results. We intuitively expect that for higher volume fractions, the critical yield number is larger. Not only here do we establish that this is the case, but also we show that short-range interactions of bubbles increase the critical yield number even more dramatically for bubble clouds. The results show that the critical yield number is a linear function of volume fraction in the dilute regime. An algebraic expression model is given to approximate the critical yield number (semi-empirically) based on the numerical experiment in the studied range of $0\le \phi \le 0.31$ , together with lower and upper estimates.

Determination of Critical Productivity Level on Cluster-Based Area of Rice Crop Insurance in Java

<strong>Indonesian</strong><br />Kesenjangan tingkat produktivitas padi di Indonesia cukup besar yang di antaranya dipengaruhi oleh luasnya wilayah pertanaman. Hal ini berdampak pada desain dan penerapan model Asuransi Usaha Tani Padi (AUTP) berbasis produktivitas. Perluasan klaster pada tingkat provinsi diperkirakan dapat mengurangi keragaman produktivitas di tingkat wilayah kota/kabupaten sebagai risiko dasar pemanfaatan skema AUTP berbasis klaster. Klaster, sebagai wilayah atau zona, diperlukan untuk menentukan indeks kritis produktivitas yang akurat dalam rangka penghitungan tingkat premi yang tepat. Kajian ini bertujuan untuk menentukan tingkat produktivitas kritis pada lahan padi yang menerapkan skema AUTP. Kajian ini menggunakan analisis statistik dengan pendekatan batas bawah <em>Two Sigma</em> yang dapat dianggap sebagai batas produktivitas kritis untuk setiap klaster. Teknik ini memberikan persentase yang rendah atas klaim yang terjadi, serta ekspektasi dan simpangan baku dari risiko dasar kerugian. Tarif premi murni yang diperoleh adalah Rp85.191,18, hampir 2,5 kali lipat lebih kecil dibandingkan dengan menggunakan teknik lain sebagai batas poduktivitas. Hasil kajian ini mengungkapkan bahwa penggunaan skema berbasis klaster lebih baik dari skema berbasis provinsi, sebagaimana ditunjukkan oleh nilai TVaR. Kajian ini menyarankan agar Kementerian Pertanian dapat merancang model AUTP berbasis produktivitas berdasarkan klaster dengan setiap klaster memiliki nilai indeks produktivitas kritis yang berbeda untuk menetapkan tingkat premi yang dikenakan.<br /><br /><br /><strong>English</strong><br />There is a large gap in productivity of paddy in Indonesia which is, among others affected by the area size of crop planting. This condition should influence the design and application model of the rice crop insurance scheme. Developing clusters under the province level is recommended to reduce the heterogeneous productivity as basis risk within regencies/municipalities in improving the area yield index of crop insurance policy in Indonesia. Clusters, as the zone, are necessary to determine accurate critical yield index leading to a more precise premium rate making. This study aims to determine critical productivity level on rice crop insurance area. This study applied statistical analysis using the lower bound of Two Sigma as a critical yield for each cluster. This technique provides a small percentage of claim, and the expectation and standard deviation of basis risk loss. The pure premium rate obtained from the analysis is IDR85,191.18, that is almost 2.5 times less than using other methods as trigger productivity. The analysis result emphasized that the use of the cluster-based scheme is better than the province-based as shown by TVaR value. The study suggests that the Ministry of Agriculture could design the area yield index based on clusters as each cluster will have a different critical productivity index with adjusted premium rate value.

AZOLLA: POTENTIAL BIOFERTILIZER FOR INCREASING RICE PRODUCTIVITY, AND GOVERNMENT POLICY FOR IMPLEMENTATION

Rice is the staple food for the significant population of Asia. Due to projected population growth in this region, the demand for this food is also predicted to be increased exponentially soon. Nitrogen (N) plays a dominant role in increasing rice yield as it is the most critical yield-limiting nutrient of rice. Chemical N fertilizers which are a major source in supplying N nutrients to rice, have adverse effects on overall soil and environmental health in the long term. The application of free-floating aquatic fern Azolla as a biofertilizer can be an alternative to improve rice yield without degrading the environment. It provides a natural source of many nutrients, especially N, improves the availability of other nutrients, plays a critical role in weed suppression, enhances soil organic matter, and improves efficiency of the inorganic fertilizers while maintaining the suitable soil pH condition for rice growth, which overall contribute to rice yield increment. Therefore, Azolla application has tremendous potential to improve soil health and boost yield sustainability.

Tectonic regime variety and stability in mantle convection with strain-induced weakening

&lt;p&gt;Earth's tectonic evolution and its link to global mantle dynamics are controlled by the pre-existing structure of the lithosphere which guides how strain localizes and causes the necessary weakness to (re-)activate plate boundaries. Recent models of global-scale mantle convection have self-consistently reproduced Earth-like tectonic regimes, consistent with several aspects of today&amp;#8217;s observed tectonics. In many cases these models ignore the memory on pre-existing deformation though. Here, a mantle convection model is advanced to include the associated rheological inheritance via a parameterization of strain-induced plastic (brittle) weakening. Based on more than 180 simulations in a wide 2D cartesian box, the control of strain-induced weakening on the resulting tectonic regime is demonstrated. Strain-induced brittle weakening impacts the stability fields of the different tectonic regimes observed, but to first order it does not generate new tectonic regimes or change the dynamics of a given regime (e.g., its characteristic surface mobility). A time-dependent plate-like regime similar to Earth's becomes more feasible with decreasing critical strain at (and above) which maximum weakening is observed. It is less feasible with increasing temperature-dependence of the healing rate, but remains a possibility at small critical strain. While the critical yield stress that still allows for plate-like behavior is apparently larger with strain-induced weakening considered, the effective shift (incorporating the yield stress reduction due to strain weakening) is relatively small and only about 10% under the tested conditions. Strain accumulation in stable continental lithosphere is generally small because of the necessity of high rheological strength. This holds true even for continental collision events, although at least some strain is accumulated and preserved following such events in the immediate proximity of the colliding continental margins.&lt;/p&gt;&lt;div&gt;&amp;#160;&lt;/div&gt;

Machine Learning for Predicting the Critical Yield Stress of High Entropy Alloys

We applied machine learning models to predict the relationship between the yield stress and the stacking fault energies landscape in high entropy alloys. The data for learning in this work were taken from phase-field dislocation dynamics simulations of partial dislocations in face-centered-cubic metals. This study was motivated by the intensive computation required for phase-field simulations. We adopted three different ways to describe the variations of the stacking fault energy (SFE) landscape as inputs to the machine learning models. Our study showed that the best machine learning model was able to predict the yield stress to approximately 2% error. In addition, our unsupervised learning study produced a principal component that showed the same trend as a physically meaningful quantity with respect to the critical yield stress.

Chemical Mechanical Planarization-Related to Contaminants: Their Sources and Characteristics

Chemical mechanical planarization (CMP) process has been widely used to planarize a variety of materials including dielectrics, metal, and semiconductors in Si-based semiconductor devices. It is one of the most critical steps to achieve the nanolevel wafer and die scale planarity. However, various contaminants are observed on the wafer surfaces after the CMP process, and they become the most critical yield detractor over many generations of rapidly diminishing feature sizes because they have the most direct impacts on device performance and reliability. This book chapter provides (1) CMP consumables-induced contaminants such as residual particles, surface residues, organic residues, pad debris and metallic impurities, pad contamination, watermark, etc., (2) brush-induced cross-contamination during post CMP cleaning, (3) post-CMP cleaning for removing these contaminants. Fundamental understanding of the formation of various types of CMP contaminants and their characteristics will significantly benefit the development of next-generation CMP slurries and post-CMP cleaning solutions.