Analysis and Experimental Investigation of Vibration Characteristics of Rotary Platform of Hydraulic Excavator under Complex Working Conditions

The rotary platform is the load-bearing substrate of a hydraulic excavator. The dynamic characteristics of the rotary platform directly affect the reliability and safety of the whole machine of a hydraulic excavator. In this work, the characteristics of the main external excitations acting on the hydraulic excavator such as the engine excitation, pressure pulsation excitation of the piston pump, inertial excitation of the working device, and road excitation are analyzed. The vibration transmission paths under the action of external excitations are ascertained. A vibration test method for the rotary platform of the hydraulic excavator is proposed. The vibration characteristics of the rotary platform under complex working conditions are researched, and the internal relationships between the vibration characteristics of the rotary platform and the engine excitation, pressure pulsation excitation of the piston pump, and road excitation are analyzed experimentally. The results show that the rotary platform is subjected to different excitations when it is under different working conditions. Moreover, the internal relationships between the dynamic characteristics of the rotary platform and the external excitation characteristics can be discovered by analyzing the vibration signals of the rotary platform, and the dynamic characteristics of the whole machine of the hydraulic excavator can be deeply studied based on the vibration characteristics of the rotary platform.

Hydrogen Safety Prediction and Analysis of Hydrogen Refueling Station Leakage Accidents and Process Using Multi-Relevance Machine Learning

Hydrogen energy vehicles are being increasingly widely used. To ensure the safety of hydrogenation stations, research into the detection of hydrogen leaks is required. Offline analysis using data machine learning is achieved using Spark SQL and Spark MLlib technology. In this study, to determine the safety status of a hydrogen refueling station, we used multiple algorithm models to perform calculation and analysis: a multi-source data association prediction algorithm, a random gradient descent algorithm, a deep neural network optimization algorithm, and other algorithm models. We successfully analyzed the data, including the potential relationships, internal relationships, and operation laws between the data, to detect the safety statuses of hydrogen refueling stations.

Understanding the Evolution of Government Attention in Response to COVID-19 in China: A Topic Modeling Approach

The effective control over the outbreak of COVID-19 in China showcases a prompt government response, in which, however, the allocation of attention, as an essential parameter, remains obscure. This study is designed to clarify the evolution of the Chinese government’s attention in tackling the pandemic. To this end, 674 policy documents issued by the State Council of China are collected to establish a text corpus, which is then used to extract policy topics by applying the latent dirichlet allocation (LDA) model, a topic modelling approach. It is found that the response policies take different tracks in a four-stage controlling process, and five policy topics are identified as major government attention areas in all stages. Moreover, a topic evolution path is highlighted to show internal relationships between different policy topics. These findings shed light on the Chinese government’s dynamic response to the pandemic and indicate the strength of applying adaptive governance strategies in coping with public health emergencies.

DNA barcodes and morphology reveal two new species of Monodiamesa Kieffer (Diptera: Chironomidae: Prodiamesinae) in Tibetan Plateau

Two Monodiamesa species collected in all stages and both sexes from the Tibetan Plateau are erected as M. secunditibetica Han and Tang, sp. n. and M. bonalpicola Han and Tang, sp. n. Molecular analysis of barcodes (COI-5P) for some related known species confirms the species validity and allows inference of internal relationships. Detailed description, habitat ecology and geographical information of two new species are provided. Additionally, brief comments on some known eastern Palaearctic species of Monodiamesa are made to give insights on further study.

Importance of the postcranial skeleton in eusuchian phylogeny: Reassessing the systematics of allodaposuchid crocodylians

Our current knowledge on the crocodyliform evolution is strongly biased towards the skull morphology, and the postcranial skeleton is usually neglected in many taxonomic descriptions. However, it is logical to expect that it can contribute with its own phylogenetic signal. In this paper, the changes in the tree topology caused by the addition of the postcranial information are analysed for the family Allodaposuchidae, the most representative eusuchians in the latest Cretaceous of Europe. At present, different phylogenetic hypotheses have been proposed for this group without reaching a consensus. The results of this paper evidence a shift in the phylogenetic position when the postcranium is included in the dataset, pointing to a relevant phylogenetic signal in the postcranial elements. Finally, the phylogenetic relationships of allodaposuchids within Eusuchia are reassessed; and the internal relationships within Allodaposuchidae are also reconsidered after an exhaustive revision of the morphological data. New and improved diagnoses for each species are here provided.

Two new, remarkably colored species of the Neotropical catfish genus Cetopsorhamdia Eigenmann & Fisher, 1916 (Siluriformes, Heptapteridae) from Chapada dos Parecis, western Brazil, with an assessment of the morphological characters bearing on their phylogenetic relationships

Two new species of heptapterid catfish genus Cetopsorhamdia are described from close localities in western Brazil, at Chapada dos Parecis, an area with extremely high level of endemism. One species is from the upper Rio Madeira system, Rondônia State, and the other from the upper Rio Tapajós system, Mato Grosso State. The two species are diagnosed, among several other features, by their markedly distinctive color patterns, with the former having well-defined quadrangular marks in trunk flanks while the latter bearing irregular, vertical bars along the trunk. The monophyly of Cetopsorhamdia is discussed, with two putative synapomorphies being proposed to support the genus. Potentially informative morphological characters to resolve the internal relationships of the genus are presented and discussed. Despite the striking external differences between the two species herein described, they are found to likely form a clade.

Factors Influencing Sleeve Grouting Quality for Prefabricated Building: An Interpretive Structural Modeling Approach

The defect in quality caused by the noncompactness of sleeve grouting has become the main obstacle restricting the further implementation of the prefabricated building in China. Studies have been conducted to explore the influencing factors of inadequate grouting; however, few studies attempt to investigate the complex interrelationship and lack of systematic cognition among these factors. To fill this gap, this study conducted a comprehensive literature review to collect the influencing factors of sleeve grouting and verified the reliability of these factors using the combined methods of brainstorming and semistructured expert discussion. A total of 18 key factors were identified and determined. The structural interpretation model (SIM) and Matrice d’Impacts Croisés Multiplication Appliquée à un Classement (MICMAC) approaches were then used to analyze, depict, and explain the internal relationships between the factors. The results indicate that all factors were classified into six levels, among which poor responsibility of supervisors and weather conditions are the most basic factors, while grouting speed and a loose-sealing rubber plug are the most important factors. Finally, a three-level control strategy was proposed to improve the compactness quality of sleeve grouting. The research findings provide valuable guidelines for managers to eliminate the grouting quality defect and to further the development of prefabricated buildings in China.

Mentality as Category of Social Philosophy in the Post-Pandemic Society

The concept of mentality in the context of today's post-pandemic society, its role in the development of historical and socio-postmodern scientific thought are analyzed. Its correlation with other categories has been determined, revealing phenomena that are close in meaning. Revealed the significance of the category of mentality for the study of the development of society.Mentality as a system is a categorical characteristic of a nation, and hence of a society, the core of which is a given nation. The study of mentality allows us to understand the internal relationships in society identify the internal reasons for the development of society and do praxeological research. The analysis of mentality within the framework of social philosophy cannot be limited to a certain time period (era), this category characterizes the nation and society at the present stage, accumulating in itself all the historical influences and changes projected at the present.The article examines the phenomenon of mentality as a system of internal deep-psychological socio-cultural attitudes of the individual. The article considers and substantiates a mental approach to understanding the phenomena of socially individual life. The philosophical and educational aspects of the formation of personality mentality and the main "problematic sides" of modern education through the prism of the mental approach are actualized.

A milestone for Pentatomoidea: Grazia et al. 2008—What do we know and where can we go?

Pentatomoidea is the third largest superfamily in Heteroptera. The internal systematics and classification of this superfamily have an intricate history. The paper by Grazia et al. (2008) is a milestone to the phylogenetic hypothesis of Pentatomoidea. Subsequent papers explored the limited conclusions and unanswered questions left by Grazia et al. (2008). We proposed to look at the body of knowledge produced since Grazia et al. (2008) and to compile the molecular data for Pentatomoidea deposited in Genbank to achieve three aims: (i) to evaluate the advances on the phylogenetic relationships of the Pentatomoidea; (ii) to produce a phylogenetic hypothesis based on molecular data deposited in Genbank; and (iii) to highlight the shortcomings and strengths of the available data. We retrieved sequences of four molecular markers (COI, 16S, 18S, and 28S) for 167 terminal taxa, including 149 pentatomoids. A concatenated matrix was analyzed under maximum likelihood (ML) and parsimony (MP). Both methods supported the monophyly of Pentatomoidea, and poorly resolved internal relationships among the families. Acanthosomatidae, Dinidordae, Pentatomidae, Scutelleridae, Thaumastellidae, and Urostylididae were monophyletic (under ML and MP), and also Plataspidae and Thyreocoridae (under ML). Tessaratomidae and Cydnidae were non-monophyletic under both methods. Our results were compared to the phylogenetic hypotheses proposed for Pentatomoidea. The analysis of the data available on the GenBank allowed us to affirm that many problems mentioned previously remain unsolved, even though the sampling of terminals has increased. In summary, the efforts in the last two decades to better understand the relationships within the Pentatomoidea have been insufficient to propose robust advances in phylogenetic hypothesis for the group. We discuss topics we understand are paramount to upcoming developments:1) better taxon sample; 2) collection management; 3) increased markers; and 4) morphology and anatomical ontology.

Balance of the built environment in structural terms

he s ubject o f t his w ork i s a n i ndepth analysis of the structure of the built environment as a system of organised relations. Three elementary aspects expressed in binary oppositions were distinguished: interior – exterior (formal aspect), individual – collective (social aspect), variable – permanent (dynamic aspect). These aspects reflect the diverse psychophysical needs and existential states of a human being. The reorganisation of a habitat is a change in the internal relationships of these categories in a specific region and spatial scale. A healthy environment can be defined as one that balances polar categories at each level of the analysis. Reforms and re-evaluations in the built environment can be interpreted as attempts to restore balance, as illustrated with examples from the history of architecture and urban planning. The results of the work contribute to the general theory of the built environment, essential for the proper design process in a wide spectrum of spatial scale.