Load Bearing Clip Angle Design -- Phase II

The report presents the second phase of a research project aimed at developing design methods for three limit states of CFS clip angles: shear, compression, and pull-over of the screw connections. In the Phase II work, the research focus was on investigating (1) the fastener pattern effects on the behavior and strength of clip angles; (2) the serviceability of clip angles subjected to tension; (3) the strength and behavior of clip angles subjected to combined shear and bending. Based on the research findings, revision to the Phase I method was proposed to account for the impact of the fastener spacing. Analytical approach to evaluate the serviceability of clip angles in tension was developed. The experimental results of the combined loading verified design equations proposed in this research project

HpGAN: Sequence Search with Generative Adversarial Networks

Sequences play an important role in many engineering applications and systems. Searching sequences with desired properties has long been an interesting but also challenging research topic. This article proposes a novel method, called HpGAN, to search desired sequences algorithmically using generative adversarial networks (GAN). HpGAN is based on the idea of zero-sum game to train a generative model, which can generate sequences with characteristics similar to the training sequences. In HpGAN, we design the Hopfield network as an encoder to avoid the limitations of GAN in generating discrete data. Compared with traditional sequence construction by algebraic tools, HpGAN is particularly suitable for intractable problems with complex objectives which prevent mathematical analysis. We demonstrate the search capabilities of HpGAN in two applications: 1) HpGAN successfully found many different mutually orthogonal complementary code sets (MOCCS) and optimal odd-length Z-complementary pairs (OB-ZCPs) which are not part of the training set. In the literature, both MOCSSs and OB-ZCPs have found wide applications in wireless communications. 2) HpGAN found new sequences which achieve four-times increase of signal-to-interference ratio--benchmarked against the well-known Legendre sequence--of a mismatched filter (MMF) estimator in pulse compression radar systems. These sequences outperform those found by AlphaSeq.Comment: 12 pages, 16 figure

High energy product of MnBi by field annealing and Sn alloying

Permanent-magnet materials are one cornerstone of today’s technology, abundant in disk drives, motors, medical equipment, wind generators, and cars. A continuing challenge has been to reconcile high permanent-magnet performance with low raw-material costs. This work reports a Mn-Bi-Sn alloy exclusively made from inexpensive elements, exhibiting high values of Curie-temperature, magnetization, anisotropy, coercivity, and energy product. The samples are produced by field annealing of rapidly quenched Sn-containing MnBi alloys, where the improvement of the magnetic properties is caused by the substitutional occupancy of the 2c sites in the hexagonal NiAs structure by Sn. The substitution modifies the electronic structure of the compound and enhances the magnetocrystalline anisotropy, thereby improv- ing the coercivity of the compound. The energy product reaches 114 kJ/m3 (14.3 MGOe) at room temperature and 86 kJ/m3 (10.8 MGOe) at 200○C; this value is similar to that of the Dy-free Nd2Fe14B and exceeds that of other rare-earth-free permanent-magnet bulk alloys, as encountered in automotive applications

Texture development and coercivity enhancement in cast alnico 9 magnets

The effect of Y addition and magnetic field on texture and magnetic properties of arc-melted alnico 9 magnets has been investigated. Small additions of Y (1.5 wt.%) develop a (200) texture for the arc-melted alnico 9 magnet. Such a texture is hard to form in cast samples. To achieve this goal, we set up a high-field annealing system with a maximum operation temperature of 12500 C. This system enabled annealing in a field of 45 kOe with subsequent draw annealing for the solutionized buttons; we have been able to substantially increase remanence ratio and coercivity, from 0.70 and 1200 Oe for the Y-free alnico 0 to 0.90 and 1400 Oe for the Y-doped alnico 9, respectively. A high energy product of 7.3 MGOe has been achieved for the fully heat-treated Y-doped alnico 9. The enhancement of coercvity is believed to arise from the introduction of magnetocrystalline anisotropy from 80 nm Y2Co17- type grains, which are exchange-coupled to the main-phase alnico rods

Identification of genes regulated by Wnt/β-catenin pathway and involved in apoptosis via microarray analysis

BACKGROUND: Wnt/β-catenin pathway has critical roles in development and oncogenesis. Although significant progress has been made in understanding the downstream signaling cascade of this pathway, little is known regarding Wnt/β-catenin pathway modification of the cellular apoptosis. METHODS: To identify potential genes regulated by Wnt/β-catenin pathway and involved in apoptosis, we used a stably integrated, inducible RNA interference (RNAi) vector to specific inhibit the expression and the transcriptional activity of β-catenin in HeLa cells. Meanwhile, we designed an oligonucleotide microarray covering 1384 apoptosis-related genes. Using oligonucleotide microarrays, a series of differential expression of genes was identified and further confirmed by RT-PCR. RESULTS: Stably integrated inducible RNAi vector could effectively suppress β-catenin expression and the transcriptional activity of β-catenin/TCF. Meanwhile, depletion of β-catenin in this manner made the cells more sensitive to apoptosis. 130 genes involved in some important cell-apoptotic pathways, such as PTEN-PI3K-AKT pathway, NF-κB pathway and p53 pathway, showed significant alteration in their expression level after the knockdown of β-catenin. CONCLUSION: Coupling RNAi knockdown with microarray and RT-PCR analyses proves to be a versatile strategy for identifying genes regulated by Wnt/β-catenin pathway and for a better understanding the role of this pathway in apoptosis. Some of the identified β-catenin/TCF directed or indirected target genes may represent excellent targets to limit tumor growth

Chiral Magnetism and High-Temperature Skyrmions in B20-Ordered Co-Si

Magnets with chiral crystal structures and helical spin structures have recently attracted much attention as potential spin-electronics materials, but their relatively low magnetic-ordering temperatures are a disadvantage. While cobalt has long been recognized as an element that promotes high-temperature magnetic ordering, most Co-rich alloys are achiral and exhibit collinear rather than helimagnetic order. Crystallographically, the B20-ordered compound CoSi is an exception due to its chiral structure, but it does not exhibit any kind of magnetic order. Here, we use nonequilibrium processing to produce B20-ordered Co1+xSi1−x with a maximum Co solubility of x = 0.043. Above a critical excess-Co content (xc = 0.028), the alloys are magnetically ordered, and for x = 0.043, a critical temperature Tc = 328 K is obtained, the highest among all B20-type magnets. The crystal structure of the alloy supports spin spirals caused by Dzyaloshinskii-Moriya interactions, and from magnetic measurements we estimate that the spirals have a periodicity of about 17 nm. Our density-functional calculations explain the combination of high magnetic- ordering temperature and short periodicity in terms of a quantum phase transition where excess-cobalt spins are coupled through the host matrix

Authenticating the geographic origins of Atractylodes lancea rhizome chemotypes in China through metabolite marker identification

IntroductionAtractylodes lancea is widely distributed in East Asia, ranging from Amur to south-central China. The rhizome of A. lancea is commonly used in traditional Chinese medicine, however, the quality of products varies across different regions with different geochemical characteristics.MethodThis study aimed to identify the chemotypes of A. lancea from different areas and screen for chemical markers by quantifying volatile organic compounds (VOCs) using a targeted metabolomics approach based on GC–MS/MS.ResultsThe A. lancea distributed in Hubei, Anhui, Shaanxi, and a region west of Henan province was classified as the Hubei Chemotype (HBA). HBA is characterized by high content of β-eudesmol and hinesol with lower levels of atractylodin and atractylon. In contrast, the Maoshan Chemotype (MA) from Jiangsu, Shandong, Shanxi, Hebei, Inner Mongolia, and other northern regions, exhibited high levels of atractylodin and atractylon. A total of 15 categories of VOCs metabolites were detected and identified, revealing significant differences in the profiles of terpenoid, heterocyclic compound, ester, and ketone among different areas. Multivariate statistics indicated that 6 compounds and 455 metabolites could serve as candidate markers for differentiating A. lancea obtained from the southern, northern, and Maoshan areas.DiscussionThis comprehensive analysis provides a chemical fingerprint of selected A. lancea. Our results highlight the potential of metabolite profiling combined with chemometrics for authenticating the geographical origin of A. lancea