Continuity of bridges composed of simple-span precast prestressed concrete girders made continuous

Bridges composed of simple-span, precast, prestressed concrete girders made continuous via cast-in-place decks and diaphragms are continuous only for live loads and superimposed dead loads. The continuity diaphragms often crack due to time dependent effects in the girders. These cracks not only impair bridge ascetics and durability, but also reduce degree of continuity . A related issue is that joint construction is time consuming and expensive due to reinforcement congestion. This dissertation presents a series of field tests, analytical studies, and laboratory experiments concerning the design and performance of this type of bridge. Based on a survey of the state departments of transportation in the U.S. and a literature review, the current practice is evaluated. Three bridges in New Jersey were instrumented and tested. Results show that the degree of continuity ranges from 0% to 90%. A comparison of the support detail suggests that anchor bolts be sheathed to allow free rotation of the girders. A computer program called CONTINUITY is developed to analyze the restraint moments and the degree of continuity of bridges up to four continuous spans. The program takes into account concrete creep and shrinkage and strand relaxation. For concrete creep and shrinkage, users can choose from three different models: ACI-209 (American Concrete Institute), CEB-FIP (European) and HPC (High Performance Concrete). Support details and cracking of the composite girder and diaphragm sections are also considered in the program. Three-dimensional finite element analyses have been carried out to further study factors affecting restraint moments. The study confirms that the girder age at continuity plays a vital role in developing the restraint moments and that the amount of positive moment reinforcement at the support has a negligible effect on the resultant mid-span moment. As part of this research a new continuity connection is developed using Carbon Fiber Reinforced Polymer (CFRP) composites. By making the girders continuous for slab self-weight as well, the additional negative moment over the continuity support will counteract the positive restraint moment and limit it below the cracking moment. Thus, cracks will not form and positive moment reinforcement is not needed in the diaphragm. Total 20 laboratory tests were carried out to validate the new connection. Results show that CFRP is effective for improving the continuity and performance of bridges of this type. Recommendations for the use of CFRP reinforcement and a design example are also presented

Learning to Use Chopsticks in Diverse Gripping Styles

Learning dexterous manipulation skills is a long-standing challenge in computer graphics and robotics, especially when the task involves complex and delicate interactions between the hands, tools and objects. In this paper, we focus on chopsticks-based object relocation tasks, which are common yet demanding. The key to successful chopsticks skills is steady gripping of the sticks that also supports delicate maneuvers. We automatically discover physically valid chopsticks holding poses by Bayesian Optimization (BO) and Deep Reinforcement Learning (DRL), which works for multiple gripping styles and hand morphologies without the need of example data. Given as input the discovered gripping poses and desired objects to be moved, we build physics-based hand controllers to accomplish relocation tasks in two stages. First, kinematic trajectories are synthesized for the chopsticks and hand in a motion planning stage. The key components of our motion planner include a grasping model to select suitable chopsticks configurations for grasping the object, and a trajectory optimization module to generate collision-free chopsticks trajectories. Then we train physics-based hand controllers through DRL again to track the desired kinematic trajectories produced by the motion planner. We demonstrate the capabilities of our framework by relocating objects of various shapes and sizes, in diverse gripping styles and holding positions for multiple hand morphologies. Our system achieves faster learning speed and better control robustness, when compared to vanilla systems that attempt to learn chopstick-based skills without a gripping pose optimization module and/or without a kinematic motion planner

Comprehensive analysis of clinical significance of stem-cell related factors in renal cell cancer

<p>Abstract</p> <p>Background</p> <p>C-MYC, LIN28, OCT4, KLF4, NANOG and SOX2 are stem cell related factors. We detected whether these factors express in renal cell carcinoma (RCC) tissues to study their correlations with the clinical and pathological characteristics.</p> <p>Methods</p> <p>The expressions of c-MYC, LIN28, SOX2, KLF4, OCT4 and NANOG in 30 RCC patients and 5 non-RCC patients were detected with quantitative real-time reverse transcription-PCR (qRT-PCR). The data were analyzed with Wilcoxon signed rank sum test and x²test.</p> <p>Results</p> <p>In RCC group, c-MYC expression was significantly higher in RCC tissues compared with normal tissues (P < 0.05). The expression levels of OCT4, KLF4, NANOG and SOX2 were significantly lower in RCC tissues compared with normal tissues (P < 0.05). LIN28 expression level was not significant. No difference was observed when it comes to clinical and pathological characteristics such as gender, age, tumor size, cTNM classification and differentiation status (P > 0.05). Also the expression levels of all above factors were not significantly changed in non-RCC group (P > 0.05).</p> <p>Conclusions</p> <p>The present analysis strongly suggests that altered expression of several stem cell related factors may play different roles in RCC. C-MYC may function as an oncogene and OCT4, KLF4, NANOG and SOX2 as tumor suppressors.</p

Guided learning of control graphs for physics-based characters

The difficulty of developing control strategies has been a primary bottleneck in the adoption of physics-based simulations of human motion. We present a method for learning robust feedback strategies around given motion capture clips as well as the transition paths between clips. The output is a control graph that supports real-time physics-based simulation of multiple characters, each capable of a diverse range of robust movement skills, such as walking, running, sharp turns, cartwheels, spin-kicks, and flips. The control fragments which comprise the control graph are developed using guided learning. This leverages the results of open-loop sampling-based reconstruction in order to produce state-action pairs which are then transformed into a linear feedback policy for each control fragment using linear regression. Our synthesis framework allows for the development of robust controllers with a minimal amount of prior knowledge.Computer Science, Department ofScience, Faculty ofUnreviewedFacult

Taxonomic revision of the genus Xenogryllus Bolívar, 1890 (Orthoptera, Gryllidae, Eneopterinae, Xenogryllini)

Jaiswara, Ranjana, Dong, Jiajia, Ma, Libin, Yin, Haisheng, Robillard, Tony (2019): Taxonomic revision of the genus Xenogryllus Bolívar, 1890 (Orthoptera, Gryllidae, Eneopterinae, Xenogryllini). Zootaxa 4545 (3): 301-338, DOI: https://doi.org/10.11646/zootaxa.4545.3.

Taxonomic revision of the genus Xenogryllus Bolívar, 1890 (Orthoptera, Gryllidae, Eneopterinae, Xenogryllini)

International audienceSubfamily Eneopterinae has been studied for its diversified acoustic modalities and disjunct distribution. The genus Xenogryllus Bolívar, 1890 is one of the oldest genera of the subfamily, and the first genus of the tribe Xenogryllini. Xenogryllus is known for its low-frequency calling songs and wide distribution across Africa and Asia. It is known from six species and has never been subject to formal taxonomic revision and description of acoustic features of their calling songs is lacking. Therefore, this study consists of a detailed taxonomic revision of all the species. We redescribe or append their taxonomic features using external morphological features and internal genitalic structures. We update the list of Xenogryllus by describing three new species from Africa. In addition, we provide keys to identify species and describe the calling songs of five species

Sampling-based Contact-rich Motion Control

(a) A forward roll transformed to a dive roll. (b) A cartwheel retargeted to an Asimo-like robot. (c) A walk transformed onto a balance beam. Figure 1: Physically based motion transformation and retargeting. Human motions are the product of internal and external forces, but these forces are very difficult to measure in a general setting. Given a motion capture trajectory, we propose a method to reconstruct its open-loop control and the implicit contact forces. The method employs a strategy based on randomized sampling of the control within user-specified bounds, coupled with forward dynamics simulation. Sampling-based techniques are well suited to this task because of their lack of dependence on derivatives, which are difficult to estimate in contact-rich scenarios. They are also easy to parallelize, which we exploit in our implementation on a compute cluster. We demonstrate reconstruction of a diverse set of captured motions, including walking, running, and contact rich tasks such as rolls and kip-up jumps. We further show how the method can be applied to physically based motion transformation and retargeting, physically plausible motion variations, and referencetrajectory-free idling motions. Alongside the successes, we point out a number of limitations and directions for future work.

Characterization of aroma profiles and volatile organic compounds in silver carp surimi gel by GC-IMS, SPME-GC-MS, and sensory evaluation: Affected by okara insoluble dietary fiber with varied particle sizes

This study aimed to investigate the effects of okara insoluble dietary fiber (IDF) with different particle sizes on the volatile organic compounds (VOCs) and characteristic aroma compounds of silver carp surimi gel. VOCs of nano-sized IDF (NIDF), micro-sized IDF (MIDF), and silver carp surimi gels with 0.8% (w/w) NIDF or 0.8% (w/w) MIDF were analyzed by electronic nose, gas chromatography-ion mobility spectrometry (GC-IMS) and Solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC–MS) combined with sensory evaluation. Results revealed that the addition of NIDF and MIDF could affect the VOCs of surimi gels. NIDF reduced the odor activity value of some fishy aroma compounds, such as hexanal, nonanal, (E,E)-2,4-heptadienal, and 1-octen-3-ol. Moreover, NIDF increased the concentrations of VOCs with branched chains or a benzene ring, such as 2-methylbutanal, 3-methylbutanal, benzaldehyde, and phenylacetaldehyde. The overall sensory preference of surimi gel could be improved with the addition of NIDF. This study provides new ideas for the applications of okara in aroma regulation of surimi products