Canonical blow-ups of Grassmannians II

We give a linear algebraic construction of the Lafforgue spaces associated to the Grassmannians $G(2,n)$ by blowing up certain explicitly defined monomial ideals, which sharpens and generalizes a result of Faltings. As an application, we provide a family of homogeneous varieties with high complexity and with nice compactifications, which exhibits the notion of homeward compactification introduced in our previous work in a non-spherical setting

Preparation and Properties of Masonry Mortar from Spontaneous Combustion Coal Gangue

To solve the problem of gangue stockpiling, this paper intends to study the feasibility of preparing masonry mortar based on spontaneous combustion gangue. After crushing the spontaneous combustion gangue, the gangue below 4.75 mm was selected, and substituted manufactured sand to prepare masonry mortar in equal quantity. The single factor test method was used to select the replacement rate of spontaneous combustion gangue, water-binder ratio (W/B) and water reducer dosage as variables to explore their effects on the basic properties of fresh mortar mixtures, such as fluidity, apparent density and water retention of fresh mortar, and the mechanical properties of hardened mortar. The anti-frost resistance of gangue mortar was evaluated by a freezing-thawing cycle test. SPSS.20 software was used for variance analysis, and the results showed that the replacement rate of spontaneous combustion gangue, W/B and water reducer dosage on mechanical properties of mortar differences are significant (P < 0.001). With the increase of the replacement rate of spontaneous combustion gangue, the mortar strength decreases, and with the rise of W/B, the mortar strength raises first and then reduces, while with the increase of the water reducer dosage, the mortar strength increases first and then decreases. Spontaneous combustion gangue mortar shows better anti-frost resistance under the freezing-thawing cycle. After 50 freezing-thawing cycles, the maximum mass and strength loss rate of mortar specimens are 2.4 % and 12.67 %, respectively. When the replacement rate of spontaneous combustion coal gangue is 100 %, the mechanical properties and anti-frost resistance of mortar both meet the requirements of the standard and realize the maximum utilization of gangue waste resources. This paper aims to provide theoretical support for the application of spontaneous combustion gangue in masonry mortar

Characterization and Analysis of Plastic Instability in an Ultrafine‐Grained Medium Mn TRIP Steel

Herein, the mechanical and magnetic behavior of an ultrafine-grained (UFG) medium manganese (Mn) transformation-induced plasticity (TRIP) steel is focused on in its plastic instability. The in situ methods of digital image correlation (DIC) and magnetic Barkhausen noise (MBN) are used to macroscopically characterize the propagation of the Lüders band (stretcher–strain marks) and the evolution of MBN activities during quasistatic tensile deformation. The evolution of microstructure during the plastic instability is investigated ex situ using X-Ray diffraction (XRD) and transmission electron microscopy (TEM) for selected plastic strain states. It is showed in the results that the plastic instability of this steel is associated with an increase of hardness and enrichment of dislocation density, which can also amplify the MBN signal, while the derived coercivity behaves reversely on an overall trend due to work hardening. The different stress response of the medium Mn steel is closely related to the kinetic martensite microstructure, which in turn modifies the domain–structure response. Thus, the MBN can be used as a potential means for nondestructive evaluation (NDE) for the strengthening of the UFG medium Mn TRIP steel

SOCIAL MEDIA GENERIC ADVERTISEMENTS AND DEMAND FOR CALIFORNIA WALNUTS

61 pagesWe designed an online field experiment to examine the impact of social–media generic advertising related to walnuts on consumers’ purchasing behavior and willingness to pay (WTP). Volunteers (n = 751) were assigned into three different groups with one control and two treatment groups, shown advertisements in the form of Twitter posts, and surveyed. The control group was shown ten coffee advertisements rather than walnut advertisements. The two treatment groups randomly received either ten posts related to the health benefits of California walnuts or recipes using walnuts. After browsing the posts, participants were asked to reveal their WTP for ten different products, including raw walnuts, salted walnuts, unsalted walnuts, raw pecans, raw cashews, and more. Our results suggested that participants in the two treatment groups had higher WTP for walnuts than participants in the control group. Moreover, posts about the health benefits of walnuts increased subjects’ WTP more than posts with recipes using walnuts. In addition, the walnut–related posts also increased participants’ WTP for pecan and cashew products. This indicates that social–media generic advertising has a positive spillover effect on pecan and cashews

Configuration Synthesis and Performance Analysis of Finger Soft Actuator

Compared with the traditional rigid finger actuator, the soft actuator has the advantages of light weight and good compliance. This type of finger actuator can be used for data acquisition or finger rehabilitation training, and it has broad application prospects. The motion differences between the soft actuator and finger may cause extrusion deformation at the binding point, and the binding forces along nonfunctional direction may reduce drive efficiency. In order to reduce the negative deformation of soft structure and improve comfort, the configuration synthesis and performance analysis of the finger soft actuator were conducted for the present work. The configuration synthesis method for soft actuator was proposed based on the analysis of the physiological structure of the finger, and the soft actuator can make the human-machine closed-loop structure including n joints (n=1, 2, 3) meet the requirement of DOF (degrees of freedom). Then the typical feasible configurations were enumerated. The different typical configurations were analyzed and compared based on the establishment of mathematical models and simulation analysis. Results show that the configuration design method is feasible. This study offers a theoretical basis for designing the configuration of finger soft actuator

A Survey of Bioinspired Jumping Robot: Takeoff, Air Posture Adjustment, and Landing Buffer

A bioinspired jumping robot has a strong ability to overcome obstacles. It can be applied to the occasion with complex and changeable environment, such as detection of planet surface, postdisaster relief, and military reconnaissance. So the bioinspired jumping robot has broad application prospect. The jumping process of the robot can be divided into three stages: takeoff, air posture adjustment, and landing buffer. The motivation of this review is to investigate the research results of the most published bioinspired jumping robots for these three stages. Then, the movement performance of the bioinspired jumping robots is analyzed and compared quantitatively. Then, the limitation of the research on bioinspired jumping robots is discussed, such as the research on the mechanism of biological motion is not thorough enough, the research method about structural design, material applications, and control are still traditional, and energy utilization is low, which make the robots far from practical applications. Finally, the development trend is summarized. This review provides a reference for further research of bioinspired jumping robots

State-of-the-art review of soft computing applications in underground excavations

Soft computing techniques are becoming even more popular and particularly amenable to model the complex behaviors of most geotechnical engineering systems since they have demonstrated superior predictive capacity, compared to the traditional methods. This paper presents an overview of some soft computing techniques as well as their applications in underground excavations. A case study is adopted to compare the predictive performances of soft computing techniques including eXtreme Gradient Boosting (XGBoost), Multivariate Adaptive Regression Splines (MARS), Artificial Neural Networks (ANN), and Support Vector Machine (SVM) in estimating the maximum lateral wall deflection induced by braced excavation. This study also discusses the merits and the limitations of some soft computing techniques, compared with the conventional approaches available.publishedVersio

Primary tumor resection improves survival in patients with multifocal intrahepatic cholangiocarcinoma based on a population study

Abstract The purpose of our study was to evaluate the effect of surgery on the survival and prognosis of patients with multifocal intrahepatic cholangiocarcinoma (ICCA). Patients with multifocal ICCA were selected from the SEER (Surveillance, Epidemiology, and End Results) database between 2010 and 2016. Kaplan–Meier analyses and log-rank tests were used to evaluate the difference in survival between the surgery group and the non-surgery group. We applied the Cox proportional hazards regression model to identify prognostic factors of overall survival (OS) and cancer-specific survival (CSS). In total, 580 patients were enrolled in our study, including 151 patients who underwent surgery and 429 patients who did not. The median survival time of surgical patients was longer than non-surgical patients (OS: 25 months vs. 8 months, p < 0.001; CSS: 40 months vs. 25 months, p < 0.001). Similarly, the 5-year survival rate in the surgery group was significantly higher than those in the non-surgery group (5-year OS rate: 12.91% vs. 0%; p < 0.001; 5-year CSS rate:26.91% vs. 0%; p < 0.001). Multivariate Cox analysis showed that the OS (HR:0.299, 95% CI: 0.229–0.390, p < 0.001) and CSS (HR:0.305, 95% CI:0.222–0.419, p < 0.001) of patients undergoing surgical resection were significantly improved. Meanwhile, after propensity score matching (PSM) of the original data, we come to the same conclusion