An analytical model for quantification of geosynthetic benefits in roadway base stabilization

Stabilization of base aggregate using geosynthetics may provide improved performance in flexible pavements. Through the aggregate-geosynthetic interaction, the induced shear stress in the base aggregates is transferred to the geosynthetic resulting in the development of tensile stresses. The tensioned geosynthetic applies in turn additional lateral confinement to the aggregates to restrain their movement under repeated traffic loading. The use of geosynthetics in base stabilization has been reported to result in reduced rutting depths in roadways. Design guidelines, either empirical or mechanistic-empirical, have been established for the design of non-stabilized roadways. These guidelines, however, do not take the geosynthetic effect into account. Accordingly, the geosynthetic benefits in base stabilization need to be quantified in a way that can easily be incorporated into the existing design procedures. This study proposed an analytical model to achieve this goal. In this study, the additional lateral confinement provided by the geosynthetic was modeled as a uniform additional confining stress within the geosynthetic influence zone. The pavement section was considered as an infinitely long elastic solid under plane strain conditions, which allowed the model framework to be established using the theory of elasticity. The aggregate-geosynthetic interaction, on the other hand, was modeled using the soil-geosynthetic composite (SGC) model. As a result, an additional confining stress could be defined from the stress-displacement relationships in the elastic model framework. An increased elastic modulus could then be predicted from the additional confining stress with a specific criterion for equivalency of the original base course with additional confinement and an alternative base course with enhanced elastic modulus but without additional confinement. The increased modulus can be used as an updated property for the geosynthetic-stabilized base aggregate in mechanistic-empirical pavement design procedures. The predicted equivalent increased moduli were validated using the results from repeated loading triaxial tests of two published studies. Overall, reasonably good agreement was found between model predictions and the test results. Predictions from this model were also compared against those of another analytical model, and close results were observed. A sensitivity analysis conducted using the proposed model indicated that model predictions are particularly sensitive to the original base modulus, geosynthetic properties (including confined geosynthetic stiffness and the stiffness of the soil-geosynthetic composite) and the thickness of the geosynthetic influence zone.Civil, Architectural, and Environmental Engineerin

CARLA-Loc: Synthetic SLAM Dataset with Full-stack Sensor Setup in Challenging Weather and Dynamic Environments

The robustness of SLAM algorithms in challenging environmental conditions is crucial for autonomous driving, but the impact of these conditions are unknown while given the difficulty of arbitrarily changing the relevant environmental parameters of the same environment in the real world. Therefore, we propose CARLA-Loc, a synthetic dataset of challenging and dynamic environments built on CARLA simulator. We integrate multiple sensors into the dataset with strict calibration, synchronization and precise timestamping. 7 maps and 42 sequences are posed in our dataset with different dynamic levels and weather conditions. Objects in both stereo images and point clouds are well-segmented with their class labels. We evaluate 5 visual-based and 4 LiDAR-based approaches on varies sequences and analyze the effect of challenging environmental factors on the localization accuracy, showing the applicability of proposed dataset for validating SLAM algorithms

A Strategy to Optimize Recovery in Orthopedic Sports Injuries

An important goal for treatment of sports injuries is to have as short a recovery time as possible. The critical problem with current orthopedic implants is that they are designed to be permanent and have a high complication rate (15%) that often requires removal and replacement with a second surgery; and subsequently a second rehabilitation cycle. This study was designed to test the feasibility of having a device that could provide the needed mechanical properties, while promoting healing, for a specified amount of time and then degrade away, to shorten the recovery time. The specific strategy was to create a surface layer on a degradable metal alloy with a controllable degradation rate. Previous studies have shown the feasibility of using surface treatments to alter the surface integrity (i.e., topography, microhardness, and residual stress) leading to increased fatigue strength and a decreased degradation rate. This study was an extension of these previous studies to look at the changes in surface integrity and mechanical properties initially as well as the degradation over time for two surface treatments (shot peening and burnishing). Although the treatments improved initial properties and the burnishing treatment slowed degradation rate, the faster degradation of the base material in vitro (compared to previous studies) probably reduced the overall impact. Therefore although the study helped support the feasibility of this approach by showing the ability of the surface treatment to modify surface integrity, initial mechanical properties, and degradation rate; the degradation rate of the base material used needs to be slower and/or the surface treatment needs to create a bigger change in the degradation rate. Further it ultimately needs to be shown that the surface treatment can produce a material that will allow orthopedic devices to meet the required clinical design constraints in vivo

Formation of the synaptonemal complex in a gynogenetic allodiploid hybrid fish

Introduction: The correct pairing and separation of homologous chromosomes during meiosis is crucial to ensure both genetic stability and genetic diversity within species. In allodiploid organisms, synapsis often fails, leading to sterility. However, a gynogenetic allodiploid hybrid clone line (GDH), derived by crossing red crucian carp (Carassius auratus ♀) and common carp (Cyprinus carpio ♂), stably produces diploid eggs. Because the GDH line carries 100 chromosomes with 50 chromosomes from the red crucian carp (RCC; ♀, 2n = 2x = 100) and 50 chromosomes from the common carp (CC; C. carpio L., ♂, 2n = 2x = 100), it is interesting to study the mechanisms of homologous chromosome pairing during meiosis in GDH individuals.Methods: By using fluorescence in situ hybridization (FISH) with a probe specific to the red crucian carp to label homologous chromosomes, we identified the synaptonemal complex via immunofluorescence assay of synaptonemal complex protein 3 (SCP3).Results: FISH results indicated that, during early ovarian development, the GDH oogonium had two sets of chromosomes with only one set from Carassius auratus, leading to the failure formation of normal bivalents and the subsequently blocking of meiosis. This inhibition lasted at least 5 months. After this long period of inhibition, pairs of germ cells fused, doubling the chromosomes such that the oocyte contained two sets of chromosomes from each parent. After chromosome doubling at 10 months old, homologous chromosomes and the synaptonemal complex were identified.Discussion: Causally, meiosis proceeded normally and eventually formed diploid germ cells. These results further clarify the mechanisms by which meiosis proceeds in hybrids

GEF Innovative Forest Management Plan—Taking Grassland Forest Farm in Fengning County as an Example

Currently, China’s forest ecosystem focus is shifting from a single management objective to multiple management objectives, aiming to improve forest quality and maximize the benefits of ecosystem services. Many difficulties and problems are encountered in the long-term development of most northern state-owned forest farms—for example, the fragmentation and degradation of forest landscapes caused by poor forest management and extensive land use—resulting in an ecosystem that is unable to provide optimal services. This research was conducted on the Fengning Grassland Forest Farm, which is based on the GEF project of state-owned forest farms. We applied lessons from international advanced concepts, such as landscape restoration, and combinecombined all types of existing data and supplementary survey data on forest farms. In addition, we used multivariate statistical analysis and geostatistical analysis methods to optimize spatial layout and forest landscape structure. Strategies of landscape restoration and optimization, forest quality improvement, and grassland ecological restoration were proposed. A forest growth model was established to predict the annual growth of forests, calculate sustainable levels of annual cutting, calculate biomass and carbon sequestration in the management period, and evaluate the value of the ecological service functions of forest ecosystems in forest farms. Finally, a set of forest management methods was developed to effectively improve the sustainable management level of state-owned forest farms and enhance the service function of forest ecosystems

Spatial transformation in Shanghai: the strategy, institutional arrangement and planning procedures - the case of EXPO 2010

Within the background of post-industrialization and globalization, Shanghai is one of the initial Chinese cities to make their reflections. Also it is the one-and-only city of the developing countries which ever hosted EXPO, thus it was making the great endeavor in order to make itself as a paradigm. According to this case, we would witness the “big event” was used as a trigger of urban regeneration and development, the vision of “pre-post” strategy has become the foundation of the financial support, the “urban development corporation” - a public and quasi-public partnership was set up to implement the strategies, and the interactions between the administration and the other actors such as experts made the planning procedure more effective

CSR implementation in large enterprises : Comparision between China and Sweden

Corporate Social Responsibility (CSR) has been widely talked about over decades. CSR is a concept proposed in Western Countries firstly and it asks for business to contribute sustainable economic development and to improve the quality of life by involving other stakeholders at the same time. The CSR among countries in Asia has beenspreadingin recent years. This thesis takes a closer comparison on the CSR between China and Sweden. As a case study with qualitative strategy, its main aims are to compare the driving forces, barriers, activities and deliverables in implementation of CSR in a Sweden-China context. Two Swedish enterprises and one Chinese enterprise are used as examples here in this study and both of their primary data by interview and secondary data by CSR or Sustainability Report are utilized. Theories refer to the implementation of CSR, the CSR in China and Sweden are used to establish the conceptual framework of this study. Empirical findings show that Chinese and Swedish enterprises both implement CSR in a similar way while the differences still exist. For instance, the Swedish enterprises stress the work on philanthropic responsibility to participate in local activities, while the Chinese enterprises contribute to the society by donation in natural disaster. Their activities, driving forces, barriers and deliverables are summarized in a model, respectively. Base on this fact, this thesis argues that the difference is due to the influence of cultural and political factors. Consequently, it leads to a situation that the Swedish enterprises have an advantage in implementation on caring of employees while the Chinese enterprises are good at making contributions to the larger society. This thesis can hopefully provide insightful comparison between the implementation of CSR in both Swedish and Chinese enterprises. As a conclusion, the study recommends that the future research should focus on CSR implementation of political influence