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A novel lightweight, radiation-shielding Mg-Ta-Al layered metal-matrix composite (LMC) was successful designed by doping the extremely refractory metal (Ta) into Mg sheets. These Mg-based LMCs sheets shows excellent radiation-dose shield effect, about 145 krad·a−1, which is about 17 times of traditional Mg alloy, while its surface density is only about 0.9 g·cm−2, reducing by 60% than that of pure Ta. The quantitate relationship between radiation-dose and the materials’ thickness was also confirmed to the logistic function when the surface density is in the range of 0.6–1.5 g·cm−2. Meantime, the rolling parameters, interface microstructure and mechanical properties in both as-rolled and annealing treated samples were evaluated. The sheets possess a special dissimilar atoms diffusion transitional zone containing an obvious inter-diffusion Mg-Al interface and the unique micro-corrugated Ta-Al interface, as well as a thin Al film with a thickness of about 10 µm. The special zone could reduce the stress concentration and enhance the strength of Mg-Ta-Al LMCs. The interface bonding strength reaches up to 54–76 MPa. The ultimate tensile strength (UTS) and yield strength (TYS) of the Mg-Ta-Al sheet were high to 413 MPa and 263 MPa, respectively, along with an elongation of 5.8%. The molecular dynamics (MD) analysis results show that the two interfaces exhibit different formation mechanism, the Mg-Al interface primarily depended on Mg/Al atoms diffusion basing point defects movement, while the Ta-Al interface with a micro-interlock pining shape formed by close-packed planes slipping during high temperature strain-induced deformation process.

The deformation behavior of hot-roll-bonded Mg/Al laminated metal composites (LMCs) is investigated, focusing on the crack formation around the interface. The material demonstrates a positive strain rate sensitivity mainly arising from the Mg matrix. A diffusion layer was formed at the Mg/Al interface with a serrated morphology during the two-pass rolling process, which consists of the Al3Mg2 and Mg17Al12 phases. The mechanical responses of the LMCs are evaluated using uniaxial tension, interfacial debonding tests (in normal and shear modes), and microstructure characterization techniques, which clarify the interfacial heterogeneity. The fracture constants of the interface were calibrated and incorporated in the finite element models to predict the failure modes of heterogeneous Mg/Al interface under three-point bending. With the increased thickness ratio of the Mg layer, the damage accumulation rate decreases at the interface and increases in the Mg matrix. As a result, the failure mode transferred from interface failure to matrix fracture. The findings of the present work provide new insight into the failure mechanism in laminated metal composites under bending conditions and can provide theoretical guidance for the plastic forming of such materials.

In this study, we present an explicit crystal plasticity finite element model (CPFEM) to investigate the texture evolution during multipass tube spinning of a TA15 alloy. The texture formation mechanism is further revealed by analyzing grain rotation and slip behaviors. The results indicate that, for the grains whose c-axes are far from the normal direction (ND), the basal slip is dominant under the significant compression deformation state of spinning. Therefore, the c-axis gradually turns toward the ND. However, for the grains whose c-axes are close to the ND, the contribution ratios of other slip systems increase, especially that of prism . Under these conditions, the c-axis deviates slightly from the ND, and grains mainly rotate around the c-axis. Therefore, most of the {0001} poles cluster around the ND and {10-10} poles are distributed in the rolling-hoop plane, exhibiting an obvious basal texture component. These results imply that the CPFEM can effectively predict the formation of basal texture component during spinning. With an increase in the number of spinning pass, the texture distribution becomes slightly inhomogeneous along the ND owing to the uneven distribution of macroscopic strain. In addition, the grain rotation first increases and then decreases with deformation. The smaller grain rotation at the first pass is because a large number of basal preferentially operates in the grain with favorable orientation, resulting in localized inhomogeneous deformation. The decrease at larger deformation is due to the lower Schmidt factor of basal , which limits the grain rotation.

It is of significance to reveal the low-cycle fatigue deformation mechanism of titanium alloy with tri-modal microstructure for improving its properties. This work developed a crystal plasticity finite element model based on realistic microstructure to predict the low-cycle fatigue behavior of TA15 titanium alloys with tri-modal microstructure containing primary α (αp), secondary lamellar α (αl) and transformed β (βt). During modelling, plastic strain accumulation (PSA) and energy dissipation were used as the fatigue indicator parameter (FIP) to predict fatigue damage and life. It is found that the fatigue deformation prefers to localize at the interfaces of αp/β, αl/β and at triple junctions, which leads to the initiation of fatigue crack. In addition, the soft geometry of αl will also contribute to the strain localization inside αl grains causing fatigue damage. This is because the local lattice rotation is more prone to occur at these locations due to the tension-compression asymmetry of lattice rotation, which induces the occurrence of the microtexture and aggravates the heterogeneity of the lattice rotation, leading to the localized PSA and the total energy dissipation. And the asymmetry of lattice rotation in each cycle also leads to the tension-compression asymmetry of flow behavior. Both of the two FIPs can effectively predict fatigue life. With the strain amplitude increasing, the PSA-based model shows a relatively higher predictive accuracy of fatigue life than that of the accumulated energy dissipation-based model. The predicted fatigue life is in accordance with the C-M model.

In order to study the multi-mode damage and fracture mechanisms of thin-walled tubular parts with cross inner ribs (longitudinal and transverse inner ribs, LTIRs), the Gurson–Tvergaard–Needleman (GTN) model was modified with a newly proposed stress state function. Thus, tension damage and shear damage were unified by the new stress state function, which was asymmetric with respect to stress triaxiality. Tension damage dominated the modification, which coupled with the shear damage variable, ensured the optimal prediction of fractures of thin-walled tubular parts with LTIRs by the modified GTN model. This included fractures occurring at the non-rib zone (NRZ), the longitudinal rib (LIR) and the interface between the transverse rib (TIR) and the NRZ. Among them, the stripping of material from the outer surface of the tubular part was mainly caused by the shearing of built-up material in front of the rollers under a large wall thickness reduction (ΔT). Shear and tension deformation were the causes of fractures occurring at the NRZ, while axial tension under a large TIR interval (l) mainly resulted in fractures on LIRs. Fractures at the interface between the TIR and NRZ were due to the shearing applied by rib grooves and radial tension during the formation of ribs. This study can provide guidance for the manufacturing of high-performance aluminum alloy thin-walled tubular components with complex inner ribs.

In this study, the microstructural evolution and mechanical behaviour of the GH3128 alloy during hot deformation were investigated, which is crucial for optimising hot processing. The investigation was performed by hot tensile deformation at 750–950 °C and analysis by electron backscatter diffraction (EBSD), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results show that two types of second-phase M23C6 and MC carbide particles existed during hot deformation, with content percentages and distributions relating to the temperature. The increase in temperature gradually promoted the precipitation of the second phase in the grain boundary. Dynamic recrystallisation occurred during hot deformation via coexisting mechanisms of twin-induced nucleation and particle-stimulated nucleation. The dynamic recrystallisation fraction gradually increased with an increase in temperature. In addition, the variation law of mechanical behaviour with temperature was revealed and explained from the perspective of microstructural evolution. In particular, the elongation decreased with an increase in temperature from 800 °C to 950 °C, mainly due to the precipitation of the second phase in the grain boundary at high temperatures, coarsening of grains and decreasing of grain uniformity. Concomitantly, the fracture mechanism changed from ductile fracture to ductile brittle fracture with an increase in temperature. These results provide a theoretical basis and guidance for the hot-working process of GH3128.

Background and purposeBreast cancer is a rapidly raising healthcare problem worldwide. DESTINY-Breast04 demonstrated that trastuzumab deruxtecan (T-Dxd) had a survival advantage comparing to the physician's choice of chemotherapy for patients with HER2-low metastatic breast cancer. But at the same time, this expensive novel treatment also brought an economic burden. This study assessed the cost-effectiveness of T-Dxd based on results of DESTINY-Breast04 from the perspective of Chinese healthcare system.Materials and methodsA three-state partitioned-survival model [progression-free survival (PFS), progressive disease (PD) and death] based on data from DESTINY-Breast04 and Chinese healthcare system was used to estimate the incremental cost-effectiveness ratio (ICER) of T-Dxd vs. the physician's choice of chemotherapy for HER2-low metastatic breast cancer. Costs, quality-adjusted life-years (QALYs) and the ICER in terms of 2022 US$ per QALY gained were calculated for both hormone receptor–positive cohort and all patients. One-way and probabilistic sensitivity analyses were performed to assess the model robustness.ResultsCompared with the physician's choice of chemotherapy, T-Dxd increased costs by $104,168.30, while gaining 0.31 QALYs, resulting in an ICER of $336,026.77 per QALY in all patients. The costs of T-Dxd and the utility of PFS were the crucial factors in determining the ICER. In the hormone receptor–positive cohort, the ICER was lower than that in all patients, with the ICER of $274,905.72 per QALY. The ICER was much higher than the commonly accepted willingness-to-pay threshold ($357,96.83 per QALY).ConclusionT-Dxd as second- or subsequent-line treatment is not a cost-effective treatment option for HER2-low metastatic breast cancer from the perspective of the Chinese healthcare system.

A two-dimensional discrete dislocation plasticity model was used to examine the role of strain rate asymmetry on the Bauschinger effect (BE). A simple single crystal single slip plane model was used first to investigate stress–strain response within high strain rate regimes where the rate sensitivity is mainly governed by dislocation nucleation and the free-flight of dislocations. Both the yield strength and the BE of the specimen showed a strong correlation to the forward and reverse deformation rate. Simulations were also carried out on a single crystal with multiple slip systems. The effect of source and obstacle density on the BE and its rate dependence was investigated. We find that the rate dependence of the BE is enhanced by increasing the source density in obstacle-free specimens and is reduced by obstacles when they are present. At low strain rates, where thermally-activated dislocation escape from obstacles becomes the predominant rate-controlling mechanism, the BE of single crystals is only affected by strain rates if the activation energy is low. Grain boundaries in polycrystalline specimens and obstacles with high activation energies act as barriers to dislocation motion, suggesting that the rate dependence under low strain rate regimes is enhanced by decreasing the grain size or reducing the activation energy associated with dislocation escape from obstacles. The effect mechanisms of strain rate asymmetry on the BE can be fundamentally crucial for multiple industrial applications, including lifetime assessments of aero-engine disks, zirconium cladding of nuclear reactor and the spring-back prediction of metal forming.

Abstract Compared with conventional forming processes, ultrasonic-assisted forming technology with a high frequency and small amplitude can significantly improve the forming quality of materials. Owing to the advantages of reduced forming force, improved surface quality, avoidance of forming defects, and strengthened surface structure, ultrasonic-assisted forming technology has been applied to increasingly advanced forming processes, such as incremental forming, spinning, and micro-forming. However, in the ultrasonic-assisted forming process, there are multiple ultrasonic mechanisms, such as the volume effect and surface effect. The explanation of the effect of ultrasonic vibration (UV) on plastic deformation remains controversial, hindering the development of related technologies. Recently, many researchers have proposed many new theories and technologies for ultrasonic-assisted forming. To summarize these developments, systematic discussions on mechanisms, theoretical models, and forming performances are provided in this review. On this basis, the limitations of the current study are discussed. In addition, an outlook for ultrasonic-assisted forming is proposed: efficient and stable UV systems, difficulty forming components with complex geometry, explanation of the in-depth mechanism, a systematic theoretical prediction model, and multi-field-coupling energy-assisted forming are considered to be hot spots in future studies. The present review enhances existing knowledge of ultrasonic-assisted forming, and facilitates a fast reference for related researchers.

Background: Bevacizumab biosimilars are slowly making their way into cancer treatment, but the data on their efficacy and safety in cancer patients are still poor. We systematically summarized the current evidence for the efficacy and safety of bevacizumab biosimilars in patients with advanced non-small cell lung cancer (NSCLC) or metastatic colorectal cancer (CRC).Methods: This review searched CNKI, VIP, PubMed, Medline (Ovid), Embase, and Cochrane Library (Ovid) for randomized controlled trials of bevacizumab biosimilars treated in adults with advanced NSCLC or metastatic CRC. A pairwise meta-analysis and a Bayesian network meta-analysis based on the random-effect model were performed to summarize the evidence. We rated the certainty of evidence according to the Grading of Recommendations Assessment, Development, and Evaluation framework.Results: Ten eligible trials with a total of 5526 patients were included. Seven trials (n = 4581) were for the NSCLC population, while three trials (n = 945) were for patients with CRC. According to the pairwise meta-analysis, the efficacy (objective response rate: risk ratio (RR) 0.98 [0.92–1.04], p = 0.45; progression-free survival: hazard ratio (HR) 1.01 [0.92–1.10], p = 0.85; and overall survival: HR 1.06 [0.94–1.19], p = 0.35) and safety (incidence of grade 3–5 adverse events: odds ratio (OR) 1.03 [0.91–1.16], p = 0.65) of bevacizumab biosimilars performed no significant difference with reference biologics in patients with NSCLC as well as metastatic CRC patients (objective response rate: RR 0.97 [0.87–1.09], p = 0.60; overall survival: HR 0.94 [0.70–1.25], p = 0.66; incidence of grade 3–5 adverse events: OR 0.78 [0.59–1.02], p = 0.73). Network estimates displayed 7 types of bevacizumab biosimilars in the medication regime of NSCLC patients who had no significant difference among each other in terms of efficacy and safety. The certainty of the evidence was assessed as low to moderate. Three types of biosimilars were found to be clinically equivalent to each other in the patients with CRC, which were evaluated with very low to moderate certainty.Conclusion: In patients with advanced NSCLC or metastatic CRC, the efficacy and safety of bevacizumab biosimilars were found to be comparable with those of reference biologics and each other.

Magnesium-lithium (Mg-Li) alloys, due to their high specific strength, have great potential in the modern aviation industry. The superplastic characteristics, microstructure evolution, mechanical properties, and forming process of LZ91 Mg-Li alloys at 200°C–300°C were studied in this paper. Tensile tests show that the optimal elongation of tensile specimens is 812.6% at 300°C under a strain rate of 5 × 10 −4 s −1 . The flow stress of the material increases with strain during the high-temperature tensile testing due to the grain coarsening . Meanwhile, low dislocation densities were observed during tension, which is not sufficient for dynamic recrystallisation to occur. The finite element method is used to investigate the forming schemes of a narrow-mouth box component. Finally, this component was manufactured by the powder pressure bulging process at 300°C experimentally.

The initial texture effect of strain rate sensitivity response in magnesium alloys was studied using the quasi in situ electron backscatter diffraction technique. The strain accumulations, under uniaxial loading of both tensile and compression along the rolling direction, showed strain rate dependency. For the AZ31 magnesium sheets with strong basal texture (max intensity to 11.2), twinning first occurs at the onset of plastic deformation, resulting in macroscopic strain rate insensitivity. With further loading, the strain rate sensitivity significantly increases (with the strain rate sensitivity coefficient m increased from 0.0025 to 0.012), arising from the initiation of slip. For the WE43 alloy sheets with weak basal texture (max intensity to 2.6), the overall deformation is sensitive to strain rate under both tensile and compression. The twinning growth rate and twinned volume fraction have been used to identify whether the process is twin-dominated or slip-dominated during the plastic deformation of a magnesium alloy.

Background and PurposeThe KEYNOTE-181 study demonstrated that pembrolizumab for advanced or metastatic esophageal cancer in patients with programmed death ligand-1 (PD-L1) combined positive score (CPS) ≥ 10 had a survival advantage and better tolerability than chemotherapy. However, at the same time, pembrolizumab places an economic burden on patients. This study assessed the cost-effectiveness of pembrolizumab based on the KEYNOTE181 study.Materials and MethodsA three-state Markov model [progression-free survival (PFS), progressive disease (PD), and death] based on data from the KEYNOTE-181 study was used to estimate the incremental cost-effectiveness ratio (ICER) of pembrolizumab versus chemotherapy for advanced or metastatic esophageal cancer. The model evaluates the outcomes from the Chinese society's perspective. Costs, quality-adjusted life-years (QALYs), and the ICER in terms of 2021 US$ per QALY gained, were calculated. one-way and probabilistic sensitivity analyses were performed to evaluate the model robustness.ResultsCompared with chemotherapy, pembrolizumab increased costs by $37,201.68, while gaining 0.23 QALYs, resulting in an ICER of $163,165.26 per QALY in patients with PD-L1 CPS ≥ 10. The ICER is $202,708.62 per QALY and $163,643.19 per QALY in the total population and patients with esophageal squamous cell carcinoma, respectively. The ICER was much higher than the commonly accepted willingness-to-pay threshold ($11,105.8 per QALY). One-way and sensitivity analyses showed that the costs of pembrolizumab and the utility of PD were the crucial factors in determining the ICER, and probabilistic sensitivity analyses demonstrated pembrolizumab is unlikely to be cost-effective at a willingness-to-pay threshold of $11,105.8 per QALY. The result was robust across sensitivity analyses.ConclusionPembrolizumab is not a cost-effective treatment option for the second-line treatment of esophageal cancer from the perspective of Chinese society.

The manufacturing process is inevitably accompanied with the production of scraps, which leads to resource waste and environmental pollution. Recycling and remanufacturing are the most commonly used approaches for metal scraps due to their well-established advantages from economic and environmental perspectives. In this study, spinning experiments with 2195 Al-Li alloy tailor welded blanks produced by friction stir welding from metal scraps were conducted under different process parameter designs. And then the effects of various process parameters on spinning of thin-walled curved surface parts were systematically studied. The results of the corresponding experimental groups show that the roller attack angle, the spinning clearance, and the installation method of tailor welded blanks have the most significant effect on the weld torsion angle. In addition, it was found that along the longitude direction of spun parts, the surface roughnesses of the weld of spun parts were greatly improved under the roller nose radius of 10 mm, the spinning clearance of 1.0 mm, the constant linear velocity, and the installation method of tailor welded blanks (the lower surface of tailor welded blanks is spun by rollers), while the process parameters have little significant effect on the surface roughness along the latitude direction of spun parts. Furthermore, it can be concluded that the forming profiles of spun parts fitted the mandrel well under the roller nose radius of 6 mm, double rollers, the roller attack angle of 30° and 45°, spinning clearance of 1.5 mm, and the installation method of tailor welded blanks (the upper surface of tailor welded blanks is spun by rollers). The research results will provide guidance for the precise spinning of thin-walled curved surface parts with tailor welded blanks. Thereby, it is also beneficial for green manufacturing involving recycling and remanufacturing of metal scraps.

Cold dwell fatigue is a well-known problem in the titanium components of aircraft engines. The high temperature and low dwell stress of in-service conditions have been reported to give rise to dwell fatigue resistance through a thermal-mechanical alleviation process. Here, dwell fatigue tests at room temperature and the component operating temperature were performed on IMI834 titanium alloy to assess the microstructural effects on thermal-mechanical alleviation of cold dwell fatigue while eliminating the effect of chemical composition. The ratcheting strain rates under different loading conditions were quantitatively investigated to aid the understanding of thermal-mechanical alleviation.

To facilitate precise and convenient control of biological sample temperature, we developed a low-cost device that can be used independently or with any stereomicroscope. The purpose of the device is to control the thermal environment during experimental intervals in which a specimen must be manipulated outside of an incubator, e.g. for dissection or slide-mounting in preparation for imaging. Sample temperatures can be both cooled to below and heated to above room temperatures, and stably maintained at a precision of +/- 0.1˚C. To demonstrate the utility of this device, we report improved characterization of the penetrance of a short-acting temperature-sensitive allele in C. elegans embryos, and identification of the upper temperature threshold for embryonic viability for six Caenorhabditis species. By controlling the temperature environment even as a specimen is manipulated, this device offers consistency and flexibility, reduces environmental noise, and enables precision timing in experiments requiring temperature shifts.

OBJECTIVE:The aim was to evaluate the performance of the initial Chinese geriatric trigger tool to detect adverse drug events (ADEs) in Chinese older patients, to attempt to shorten this list for improving the efficiency of the trigger tool, and to study the incidence and characteristics of ADEs in this population. METHODS:A sample of 25 cases was randomly selected per half a month from eligible patients who aged 60 years and older, hospitalized more than 24 hours, and discharged or died between January 1, 2015 and December 31, 2017 in West China hospital. A two-stage retrospective chart review of the included inpatients were conducted. ADEs were detected using a list of 42 triggers previously selected by an expert panel by means of a Delphi method. The number of triggers identified and ADEs detected were recorded and the positive predictive value (PPV) of each trigger was calculated to select the most efficient triggers. Several variables were recorded, including age, sex, number of diseases, length of hospital stay and so on, to analyze the risk factor of ADEs. RESULTS:Among 1800 patients, 1646 positive triggers and 296 ADEs were detected in 234 (13.00%) patients. Older patients who were younger, had more medications, longer stays or more admission, and did not experience surgical operation more likely experienced ADEs. Triggers with PPV less than 5% were eliminated, which resulted in the upgraded version of Chinese geriatric trigger tool of 20 triggers with a PPV of 28.50%. This upgraded tool accounted for 99.66% of all ADEs detected. CONCLUSIONS:The upgraded version of Chinese geriatric trigger tool was an efficient tool for identifying ADEs in Chinese older patients. Future, the trigger tool could be incorporated into routine screen systems to provide real-time identification of ADEs, thereby enabling timely clinical interventions.

Neuroendocrine circuits encode environmental information via changes in gene expression and other biochemical activities to regulate physiological responses. Previously, we showed that daf-7 TGF[Formula: see text] and tph-1 tryptophan hydroxylase expression in specific neurons encode food abundance to modulate lifespan in Caenorhabditis elegans, and uncovered cross- and self-regulation among these genes (Entchev et al., 2015). Here, we now extend these findings by showing that these interactions between daf-7 and tph-1 regulate redundancy and synergy among neurons in food encoding through coordinated control of circuit-level signal and noise properties. Our analysis further shows that daf-7 and tph-1 contribute to most of the food-responsiveness in the modulation of lifespan. We applied a computational model to capture the general coding features of this system. This model agrees with our previous genetic analysis and highlights the consequences of redundancy and synergy during information transmission, suggesting a rationale for the regulation of these information processing features.

Control effect is not ideal for traditional control method and wired control system, since greenhouse temperature has such characteristics as nonlinear and longtime lag. Therefore, Fuzzy- PID control method was introduced and radio frequency chip CC1110 was applied to design greenhouse wireless intelligent monitoring and control system. The design of the system, the component of nodes and the developed intelligent management software system were explained in this paper. Then describe the design of the control algorithm Fuzzy-PID. By simulating the new method in Matlab software, the results showed that Fuzzy-PID method small overshoot and better dynamic performance compared with general PID control. It has shorter settling time and no steady-state error compared with fuzzy control. It can meet requirements in greenhouse production.

In this paper, the initial values of damage parameters in the Gurson−Tvergaard−Needleman (GTN) model are determined by a microscopic test combined with empirical formulas, and the final accurate values are determined by finite element reverse calibration. The original void volume fraction (f0), the volume fraction of potential nucleated voids (fN), the critical void volume fraction (fc), the void volume fraction at the final failure (fF) of material are assigned as 0.006, 0.001, 0.03, 0.06 according to the simulation results, respectively. The hemispherical punch stretching test of commercially pure titanium (TA1) sheet is simulated by a plastic constitutive formula derived from the GTN model. The stress and strain are obtained at the last loading step before crack. The forming limit diagram (FLD) and the forming limit stress diagram (FLSD) of the TA1 sheet under plastic forming conditions are plotted, which are in good agreement with the FLD obtained by the hemispherical punch stretching test and the FLSD obtained by the conversion between stress and strain during the sheet forming process. The results show that the GTN model determined by the finite element reverse calibration method can be used to predict the forming limit of the TA1 sheet metal.

Grain-scale strain heterogeneity characteristics play a critical role in the ductile damage behavior and mechanical properties of two-phase titanium alloys. In this work, the grain-scale strain distribution, strain heterogeneity, and strain localization of titanium alloy with tri-modal microstructure (consisting of equiaxed α (αp), lamellar α (αl), and β transformed matrix (βt)) during tensile deformation were experimentally investigated. The results show that the strain probability distribution of the whole microstructure obeys normal distribution during deformation. Significant strain heterogeneities exist in each constituent (αp, αl, and βt) and the whole microstructure. At lower macro-strain, αp and αl exhibit higher average strain than those of βt and the whole of the microstructure. Meanwhile, strain heterogeneity of each constituent is small and has a negligible change. The strain heterogeneity of the whole microstructure is mainly determined by αp. At larger macro-strain, some highly deformed regions produce and their positions do not change during further deformation. As a result, the strain heterogeneity of each constituent increases fast, and the strain heterogeneity of whole microstructure is mainly related to αl in this deformation stage. On the other hand, two types of strain localization may be generated within αp and αl and at the αp/βt and αl/βt boundaries, respectively. The former type is caused by transgranular intense slip deformation and presents crystal orientation dependence. The latter type is related to the boundary sliding and presents spatial distribution dependence for αl. These strain localizations greatly determine the micro-damages, thus forming the corresponding micro-voids within αp and αl and the micro-cracks at αp/βt and αl/βt boundaries in tri-modal microstructure at larger deformation.

Electromagnetic forming (EMF), a technology with advantages of contact-free force and high energy density, generally aims at forming parts by using a fixed coil and one-time discharge. In this study, multi-stage EMF is introduced to form a panel with stiffened grid ribs. The forming rules of the stiffened panel is revealed via analyzing the distribution and evolution of the simulated stress and strain in the ribs and web, where the grid-rib panels were decomposed as the flat panel and two panels with uni-directional ribs (ribs only in X direction or Y direction). It is shown that the forming depth is mainly attributed to the forces on the web, although electromagnetic force is applied on both the ribs and the web, especially, large force on the ribs. The ribs are subjected to uniaxial stress parallel to their directions, and the web is subjected to plane stress in the deformation region. Furthermore, the change of the uniaxial stress characteristic in the X-direction ribs is influenced by the electromagnetic force, reverse bend and inertial effect. The plastic deformation mainly occurs in the Y-direction ribs of the deformation region under a three-direction strain state.

How the nervous system internally represents environmental food availability is poorly understood. Here, we show that quantitative information about food abundance is encoded by combinatorial neuron-specific gene-expression of conserved TGFβ and serotonin pathway components in Caenorhabditis elegans. Crosstalk and auto-regulation between these pathways alters the shape, dynamic range, and population variance of the gene-expression responses of daf-7 (TGFβ) and tph-1 (tryptophan hydroxylase) to food availability. These intricate regulatory features provide distinct mechanisms for TGFβ and serotonin signaling to tune the accuracy of this multi-neuron code: daf-7 primarily regulates gene-expression variability, while tph-1 primarily regulates the dynamic range of gene-expression responses. This code is functional because daf-7 and tph-1 mutations bidirectionally attenuate food level-dependent changes in lifespan. Our results reveal a neural code for food abundance and demonstrate that gene expression serves as an additional layer of information processing in the nervous system to control long-term physiology.

Quantitative imaging has become a vital technique in biological discovery and clinical diagnostics; a plethora of tools have recently been developed to enable new and accelerated forms of biological investigation. Increasingly, the capacity for high-throughput experimentation provided by new imaging modalities, contrast techniques, microscopy tools, microfluidics and computer controlled systems shifts the experimental bottleneck from the level of physical manipulation and raw data collection to automated recognition and data processing. Yet, despite their broad importance, image analysis solutions to address these needs have been narrowly tailored. Here, we present a generalizable formulation for autonomous identification of specific biological structures that is applicable for many problems. The process flow architecture we present here utilizes standard image processing techniques and the multi-tiered application of classification models such as support vector machines (SVM). These low-level functions are readily available in a large array of image processing software packages and programming languages. Our framework is thus both easy to implement at the modular level and provides specific high-level architecture to guide the solution of more complicated image-processing problems. We demonstrate the utility of the classification routine by developing two specific classifiers as a toolset for automation and cell identification in the model organism Caenorhabditis elegans. To serve a common need for automated high-resolution imaging and behavior applications in the C. elegans research community, we contribute a ready-to-use classifier for the identification of the head of the animal under bright field imaging. Furthermore, we extend our framework to address the pervasive problem of cell-specific identification under fluorescent imaging, which is critical for biological investigation in multicellular organisms or tissues. Using these examples as a guide, we envision the broad utility of the framework for diverse problems across different length scales and imaging methods.

Electromagnetic forming (EMF), as a high-speed forming technology by applying the electromagnetic forces to manufacture sheet or tube metal parts, has many potential advantages, such as contact-free and resistance to buckling and springback. In this study, EMF is applied to form several panels with stiffened ribs. The distributions and variations of the electromagnetic force, the velocity and the forming height during the EMF process of the bi-directional panel with gird ribs are obtained by numerical simulations, and are analyzed via the comparison to those with the flat panel (non-stiffened) and two uni-directional panels (only with X-direction or Y-direction ribs). It is found that the electromagnetic body force loads simultaneously in the ribs and the webs, and the deformation of the panels is mainly driven by the force in the ribs. The distribution of force in the grid-rib panel can be found as the superposition of the two uni-directional stiffened panels. The velocity distribution for the grid-rib panel is primarily affected by the X-directional ribs, then the Y-directional ribs, and the variation of the velocity are influenced by the force distribution primarily and secondly the inertial effect. Mutual influence of deformation exists between the region undergoing deformation and the deformed or underformed free ends. It is useful to improve forming uniformity via a second discharge at the same position. Comparison between EMF and the brake forming with a stiffened panel shows that the former has more advantages in reducing the defects of springback and buckling.

Tube spinning is an effective plastic-forming technology for forming light-weight, high-precision and high-reliability components in high-tech fields, such as aviation and aerospace. However, cracks commonly occur in tube spinning due to the complexity of stress state, which severely restricts the improvement of the forming quality and forming limit of components. In this study, a finite element (FE) model coupled with Gurson-Tvergaard-Needleman (GTN) damage model for forward tube spinning of 3A21-O aluminum alloy is established and its applicability is evaluated by experiment. Meanwhile, the GTN damage model is employed to study the damage evolution for forward tube spinning of 3A21-O aluminum alloy. The results show that the FE model is appropriate for predicting the macroscopic crack appearing in uplift area for forward tube spinning, while the damage evolution in deformation area could not be predicted well due to the negative stress triaxiality and the neglect of shear deformation. Accumulation of damage in forward tube spinning occurs mainly in the uplift area. Void volume fraction (VVF) in the outer surface of the tube is higher than that in the inner surface. In addition, it is prone to cracking in the outer surface of tube in the material uplift area.

We study boundary output tracking for a flexible beam with tip payload and boundary nonlinear disturbance. By constructing an infinite-dimensional extended state observer (ESO), the total disturbance is estimated on line. A servomechanism corresponding to the reference signal and servomechanism-based output feedback control law are designed. Under such control law, we prove that the performance boundary output tracks exponentially the reference signal. By virtue of the Riesz basis approach, the Riesz basis generation and exponential stability of an coupled system are verified, and thereby the boundedness of closed-loop system is obtained. Some numerical simulations are presented to illustrate the effectiveness. [ABSTRACT FROM AUTHOR]