An unbalanced ion pair promoter (e.g.,
tetrabutylammonium sulfate),
consisting of a bulky and charge-delocalized cation and a small and
charge-localized anion, greatly accelerates nucleophilic fluorinations
using easy handling KF. We also successfully converted an inexpensive
and commercially available ion-exchange resin to the polymer-supported
ion pair promoter (A26–SO4
2–),
which could be reused after filtration. Moreover, A26–SO4
2– can be used in continuous flow conditions.
In our conditions, water is well-tolerated.
Safe and effective construction management requires tools for reducing delays, eliminating reworks, and avoiding accidents. Unfortunately, challenges still exist in current construction practices for enabling real-time interactions among project participants, field discoveries, and massive data. Extended reality (i.e., XR) could help to establish immersive and interactive virtual environments that enable real-time information exchange among humans, cyber processes, and physical environments during construction. However, limited studies have synthesized potentials, challenges, and scenarios of XR for ensuring construction safety and efficiency. This study provides a critical review that synthesizes XR in construction management. First, the authors used the PRISMA method to screen studies related to XR in construction management. Seventy-nine studies were selected and comprehensively analyzed. The authors conducted a bibliometric analysis to comprehend the spatiotemporal distributions of the selected studies. Then, the selected studies were classified into three categories: (1) progress control, (2) quality control, and (3) safety management. The authors also synthesized information for XR applications in various construction management scenarios and summarized the challenges related to XR applications. Finally, this review shed light on future research directions of XR for safe and effective construction management.
A simple and highly efficient palladium nanoparticles catalytic system was applied in Suzuki coupling reaction. This system could catalyze a variety of aryl halide and arylboronic acid substrates with a wide range of functional groups. A high turnover number of 90000 was obtained with the catalyst loading as low as 0.001 mol%. This catalyst system exhibited good stability and longevity.
In recent years, safety issues involving foundation pits have attracted extensive attention in the industry. The external angle of the foundation pit bears a greater load and is more prone to collapsing. Anchor support technology is one of the most widely used support technologies in construction engineering, but it has the problem of anchor rod crossing and colliding from the initial design stage, and this reduces anchoring force and eventually leads to many safety issues. Compared with traditional methods, Building Information Modeling (BIM) technology can save a lot of time as well as reduce costs, and applying it to concealed engineering can solve the problems that exist during the design stage and reduce unpredictable construction risks. This study proposes an optimization method based on BIM that can accurately and quickly optimize the drilling of anchor rods in the external angles of foundation pits. The results show that the proposed method can reduce the number of anchor rod collision points at the external angle of the foundation pit, minimize the loss of horizontal force caused by anchor rod collision, and ensure the safety and stability of the foundation pit support system.
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