The Cover Feature shows construction machinery actively engaged in a distibene project. The picture refers to a compound bearing the highly encumbered Ar* ligand (Ar* = C6H2−2,6‐(CHPh2)2−4‐iPr), ...which was isolated from salt‐free metathesis reactions – alongside other novel dipnictenes – during this study. The distibene shown at the construction site protrudes from other compounds of this class, as it exhibits the currently longest Sb=Sb distance 2.8605(5) Å of all thus far reported distibenes. “Construction” of dipnictenes with elongated bonds between the heavier atoms is currently of great interest in the research community, as such compounds are promising candidates for the application in the controlled activation of small molecules. More information can be found in the Research Article by R. C. Fischer and co‐workers.
A literature review revealed several major shortcomings in the analysis of construction equipment operations data, for example, the lack of using realistic or real-time positioning data that can feed ...into an equipment operations analysis or simulation model. This paper presents technology and algorithms that have the potential in aiding the automated assessment of construction site equipment operations. Utilizing commercially available low-cost global positioning system (GPS) devices enables the continuous data logging of equipment location in addition to simultaneously recording timestamps. However, before any such spatio-temporal equipment data can be reliably collected on construction sites, the error rate of the GPS devices had to be evaluated. Data analysis methods and rules for monitoring construction site equipment operations and activity were then defined. A detailed software interface was finally created that allows a user to set, analyze, and visualize several important equipment parameters towards achieving the goal of creating more realistic equipment operation analysis and potential for inclusion in simulation models. Results from field experiments show that the developed technology is able to identify and track equipment activity- and safety-related information automatically for job site performance and layout decision making, respectively. The presented work will aid construction project managers in making better decisions to plan, manage, and control equipment-related work tasks on construction sites.
Display omitted
► Continuous data collection in construction equipment operation is lacking detail. ► GPS data loggers can collect reliable location tracking data for further analysis. ► A software user interface allows detection and visualization of active job site areas. ► Information to equipment cycles, hours of operation, and proximity can be collected. ► Data can be used in application, e.g., construction equipment simulation and safety.
Over six hundred construction worker deaths occurred in the United States during the inclusive years of 2004 to 2006 that were related to construction equipment and contact collisions. This paper ...presents findings about emerging radio frequency (RF) remote sensing and actuating technology that can improve construction safety by warning or alerting workers-on-foot and equipment operators in a pro-active real-time mode once equipment gets too close in proximity to unknown or other equipment. A review is provided on the background and importance of safety related to various pieces of construction equipment. Pro-active real-time proximity and alert technology for daily construction operations is introduced to solve this problem. Results of various field experiments that tested the proximity and alert technology are presented. A discussion follows on how such technology can improve objective construction site safety data collection and lead to more effective construction workforce safety training and education.
In the construction industry, the operator's mental fatigue is one of the most important causes of construction equipment-related accidents. Mental fatigue can easily lead to poor performance of ...construction equipment operations and accidents in the worst case scenario. Hence, it is necessary to propose an objective method that can accurately detect multiple levels of mental fatigue of construction equipment operators. To address such issue, this paper develops a novel method to identify and classify operator's multi-level mental fatigue using wearable eye-tracking technology. For the purpose, six participants were recruited to perform a simulated excavator operation experiment to obtain relevant data. First, a Toeplitz Inverse Covariance-Based Clustering (TICC) method was used to determine the number of levels of mental fatigue using relevant subjective and objective data collected during the experiments. The results revealed the number of mental fatigue levels to be 3 using TICC-based method. Second, four eye movement feature-sets suitable for different construction scenarios were extracted and supervised learning algorithms were used to classify multi-level mental fatigue of the operator. The classification performance analysis of the supervised learning algorithms showed Support Vector Machine (SVM) was the most suitable algorithm to classify mental fatigue in the face of various construction scenarios and subject bias (accuracy between 79.5% and 85.0%). Overall, this study demonstrates the feasibility of applying wearable eye-tracking technology to identify and classify the mental fatigue of construction equipment operators.
•A novel approach for detecting construction equipment operator’s mental fatigue based on eye movement data is proposed.•TICC method is adopted to identify multiple levels of mental fatigue and label relevant eye movement data.•Supervised learning algorithms are used to learn four different sets of eye movement features.•Results show that SVM and LDA yield high classification performance.•The feasibility of the proposed method for detecting multi-level mental fatigue is discussed.
Cycloaddition reactions are among the most important tools for the construction of cyclic compounds in organic synthesis, since these reactions are vital to access natural products and biologically ...active compounds. Organocatalysis plays an increasingly pivotal role in these reactions, often allowing several stereocenters to be selectively created and integrated in the target molecule. Among the large number of efficient types of organocatalysts available, the diarylprolinol silyl ethers have been established as one of the most frequently used in aminocatalysis allowing for novel activation modes and reaction concepts. In this review, we will focus on the different activation modes made available by the diarylprolinol silyl ether system with the aim of highlighting their applicability in asymmetric cycloadditions for the assembly of complex molecular architectures.
Organocatalysis as a paint palette for asymmetric cycloaddition reactions.
Construction equipment related accidents, such as collisions between equipment and pedestrian workers, pose a major challenge to occupational safety at construction sites. Decrement of operators' ...hazard detection ability resulting from attention failure is a leading cause of these accidents. Although mental fatigue induced by prolonged and monotonous operating tasks is known as the primary cause of this type of failure, little is revealed on how mental fatigue influences operators' ability to detect hazardous situations and associated visual attention features. To address this issue, this study uses wearable eye-tracking technology to evaluate the impact of mental fatigue on operators' ability in hazard detection and the corresponding patterns of visual attention allocation. Twelve healthy participants performed a simulated excavator operating task in a laboratory experiment. Subjective mental fatigue assessment, hazard detection task performance, and eye movement metrics were recorded and analyzed. In the experiment, mental fatigue was effectively induced and manipulated by a Time-On-Operating (TOO) procedure. Results revealed that operators' hazard detection ability decreased with the increase in subjective mental fatigue level, reflected by significant increases in reaction time for hazards and the number of misdetections. Attention allocation-related data were further analyzed to explain the specific manifestations of hazard detection failure in visual attention. The results indicated that the decrease of operators' hazard detection ability is associated with the changes of the distributions of fixation and gaze point while mental fatigue level increases. Consequently, clear observation of surrounding hazards and related details becomes difficult for operators. The findings demonstrate the effectiveness of wearable eye-tracking technology in measuring and quantifying operators' mental fatigue and hazard detection ability. More importantly, the findings offer insights into the impairing effect of mental fatigue on operators' hazard detection ability from a visual attention perspective. Such insights provide a solid basis for developing effective safety interventions and attentional guidance-based safety training methods to mitigate relevant site accidents.
•Mental fatigue induced by prolonged operating task is assessed by utilizing wearable eye tracker.•The decrement of hazard detection ability is quantified using eye movement metrics.•The impairing effect of mental fatigue on operators' ability to detect hazard was found.•Interventions and training methods have been discussed to reduce hazard detection failures.
Over the past decades, detailed individual building energy models (BEM) on the one side and regional and country-level building stock models on the other side have become established modes of ...analysis for building designers and energy policy makers, respectively. More recently, these two toolsets have begun to merge into hybrid methods that are meant to analyze the energy performance of neighborhoods, i.e. several dozens to thousands of buildings. This paper reviews emerging simulation methods and implementation workflows for such bottom-up urban building energy models (UBEM). Simulation input organization, thermal model generation and execution, as well as result validation, are discussed successively and an outlook for future developments is presented.
The ruthenium-catalyzed azide alkyne cycloaddition (RuAAC) affords 1,5-disubstituted 1,2,3-triazoles in one step and complements the more established copper-catalyzed reaction providing the ...1,4-isomer. The RuAAC reaction has quickly found its way into the organic chemistry toolbox and found applications in many different areas, such as medicinal chemistry, polymer synthesis, organocatalysis, supramolecular chemistry, and the construction of electronic devices. This Review discusses the mechanism, scope, and applications of the RuAAC reaction, covering the literature from the last 10 years.
Isocyanides have a broad range of applications in multicomponent reactions such as Passerini and Ugi processes. Recent advances in metal catalysis have tremendously increased the versatility of ...isocyanides in organic chemistry. Suitable metal catalysts could selectively activate various C-H bonds to allow direct functionalization under mild conditions, which represents a chemical process with broad synthetic potential. The synergy from the combination of isocyanide insertion and C-H bond activation offers an efficient and powerful tool to establish complicated reactions and to construct useful substances, from which the high potential of such strategy has been convincingly demonstrated in drug discovery, organic synthesis, and materials science. The present review highlights the most recent advances of isocyanide chemistry in metal-catalyzed C-H bond functionalization.
This review demonstrates the metal-catalyzed incorporation of isocyanides into C-H functionalization to establish complicated reactions utilizing synergistic effects.
PDF
