Optimization of 3xx Aluminum Alloy Microstructures and Mechanical Properties for New Generation Ford Motor Company Engine Blocks

The use of cast aluminum components in automotive applications is increasing rapidly. Cast Al components are allowing the industry to meet the current as well as future customer and legislative requirements regarding vehicle size and performance. The 319 Al alloy, which contains 3-4wt%Cu and 6-7wt%Si, is utilized in Ford automobile engine block castings. After heat treatment, this alloy exhibits higher yield and tensile strength levels than other grades of cast Al alloys. However, some other mechanical properties of the 319 Al alloy need to be improved, and thus a lot of these alloys are not applicable for engine blocks. The bulkhead section of the engine block is susceptible to high cycle fatigue (HCF) during operation. Recent IRC work showed that it might be possible to improve microstructures and mechanical properties of 300-series of cast Al alloys through the optimization of Si, Cu and Sr levels in the castings. This project concerns the optimization of Si, Cu and Sr contents for the improvement of microstructures and properties of 300-series casting Al alloys, particularly HCF properties. In order to investigate the effects of chemical composition and cooling rate (CR) on microstructures and properties, six plates with various chemical compositions were cast at Ford CPDC. The plates were chilled at one end so that temperature gradients and different CR were created. This research project has investigated the effects of chemical compositions (Si, Cu and Sr), temperature gradient and CR on the microstructures, properties and casting defects of the Al alloys typically utilized for automotive engine blocks. A criterion has been developed for the improvement of next-generation engine component durability through the optimization of chemical compositions, and solidification conditions. The influences of heat treatment parameters on Cu phase(s) area fractions and hardness have also been investigated. The experimental work performed showed that the secondary Dendrite Arm Spacing (SDAS), Silicon Modification Level (SML), Porosity Area Fraction (PAF), Cu phase(s) area fraction (CuAF) and hardness were affected by the CR. Slight changes on the above parameters were caused by microalloying changes

Investigation on soft landing impact test of scale lunar lander model

According to the disadvantages of soft landing in two impact tests, the lunar lander full scale model within the moon gravitational field and 1/6 scale model within gravity field of the earth, the passage provides a new approach for the impact test of 1/3 scale model within gravity field of the earth. Test principle and test scheme is analyzed. Scale model prototype of the lunar lander is designed. Emulated lunar soil is prepared in terms of volcanic ash as raw material, and its mechanics performance is tested. Crushing test of selected aluminum honeycomb buffer material is analyzed as well. Also the measurement requirement of the data test is analyzed. The whole test system is verified and analyzed. Test results show that the test system presented in this test could simulate the soft landing process on the moon surface by the lunar lander. The overload would arrive minimum when the lunar lander is landing along the downhill on the symmetric mode, at the same, the rigid foot pad would not apply to lunar lander

Allylic oxidation of olefins with a manganese-based metal-organic framework

Selective oxidation of olefins to α,β-unsaturated ketones under mild reaction conditions have attracted considerable interest, since α,β-unsaturated ketones can serve to be synthetic precursors for various downstream chemical products. The major challenges inherently with this chemical oxidation are chem-, regio-selectivity as well as environmental concerns, i.e. catalyst recycle, safety and cost. Using atmospheric oxygen as an environmental friendly oxidant, we found that a metal-organic framework (MOF) constructed with Mn and tetrazolate ligand (CPF-5) showed good activity and selectivity for the allylic oxidation of olefins to α,β-unsaturated ketones. Under the optimized condition, we could achieve 98% conversion of cyclohexene and 87% selectivity toward cyclohexanone. The combination of a substoichiometric amount of TBHP (tert-butylhydroperoxide) and oxygen not only provides a cost effective oxidation system but significantly enhances the selectivity to α,β-unsaturated ketones, outperforming most reported oxidation methods. This catalytic system is heterogeneous in nature, and CPF-5 could be reused at least five times without a significant decrease in its catalytic activity and selectivity

Generation of Transgene-Free Maize Male Sterile Lines Using the CRISPR/Cas9 System

Male sterility (MS) provides a useful breeding tool to harness hybrid vigor for hybrid seed production. It is necessary to generate new male sterile mutant lines for the development of hybrid seed production technology. The CRISPR/Cas9 technology is well suited for targeting genomes to generate male sterile mutants. In this study, we artificially synthesized Streptococcus pyogenes Cas9 gene with biased codons of maize. A CRISPR/Cas9 vector targeting the MS8 gene of maize was constructed and transformed into maize using an Agrobacterium-mediated method, and eight T0 independent transgenic lines were generated. Sequencing results showed that MS8 genes in these T0 transgenic lines were not mutated. However, we detected mutations in the MS8 gene in F1 and F2 progenies of the transgenic line H17. A potential off-target site sequence which had a single nucleotide that was different from the target was also mutated in the F2 progeny of the transgenic line H17. Mutation in the MS8 gene and the male sterile phenotype could be stably inherited by the next generation in a Mendelian fashion. Transgene-free ms8 male sterile plants were obtained by screening the F2 generation of male sterile plants, and the MS phenotype could be introduced into other elite inbred lines for hybrid production

Improving Negative-Prompt Inversion via Proximal Guidance

DDIM inversion has revealed the remarkable potential of real image editing within diffusion-based methods. However, the accuracy of DDIM reconstruction degrades as larger classifier-free guidance (CFG) scales being used for enhanced editing. Null-text inversion (NTI) optimizes null embeddings to align the reconstruction and inversion trajectories with larger CFG scales, enabling real image editing with cross-attention control. Negative-prompt inversion (NPI) further offers a training-free closed-form solution of NTI. However, it may introduce artifacts and is still constrained by DDIM reconstruction quality. To overcome these limitations, we propose Proximal Negative-Prompt Inversion (ProxNPI), extending the concepts of NTI and NPI. We enhance NPI with a regularization term and reconstruction guidance, which reduces artifacts while capitalizing on its training-free nature. Our method provides an efficient and straightforward approach, effectively addressing real image editing tasks with minimal computational overhead.Comment: Code at https://github.com/phymhan/prompt-to-promp

Facile Fabrication of Hierarchical MOF–Metal Nanoparticle Tandem Catalysts for the Synthesis of Bioactive Molecules

Multifunctional metal–organic frameworks (MOFs) that possess permanent porosity are promising catalysts in organic transformation. Herein, we report the construction of a hierarchical MOF functionalized with basic aliphatic amine groups and polyvinylpyrrolidone-capped platinum nanoparticles (Pt NPs). The postsynthetic covalent modification of organic ligands increases basic site density in the MOF and simultaneously introduces mesopores to create a hierarchically porous structure. The multifunctional MOF is capable of catalyzing a sequential Knoevenagel condensation–hydrogenation–intramolecular cyclization reaction. The unique selective reduction of the nitro group to intermediate hydroxylamine by Pt NPs supported on MOF followed by intramolecular cyclization with a cyano group affords an excellent yield (up to 92%) to the uncommon quinoline N-oxides over quinolines. The hierarchical MOF and polyvinylpyrrolidone capping agent on Pt NPs synergistically facilitate the enrichment of substrates and thus lead to high activity in the reduction–intramolecular cyclization reaction. The bioactivity assay indicates that the synthesized quinoline N-oxides evidently inhibit the proliferation of lung cancer cells. Our findings demonstrate the feasibility of MOF-catalyzed direct synthesis of bioactive molecules from readily available compounds under mild conditions