Unexpected Bridge Research Articles

Isocyanide Cu(I) complexes with unexpected μ2‐bridging pseudohalides: Synthesis, characterization and catalytic activity towards CuAAC

Three neutral Cu(I) complexes bearing 2,6‐dimethylphenyl isocyanide (CNXyl) and different triatomic pseudohalogens (SCN−, OCN− and N3−) as ligands were efficiently synthesized and characterized. The solid‐state structures were unambiguously determined through single‐crystal X‐ray diffraction, revealing unexpected bridging coordination modes in the case of OCN− and N3−. All the complexes were tested for azide‐alkyne cycloaddition (CuAAC), showing interesting catalytic activity towards the formation of 1,4‐disubstituted‐1,2,3‐triazoles for the cyanato and the azido Cu(I) complexes. Both species afforded yields above 90% with 0.5 mol% of catalyst at 50°C for 24 h. Several alkynes and azides were tested using the more active azido Cu(I) complex, affording the corresponding triazoles in high yields. The azido Cu(I) complex also induced the intramolecular CuAAC in the presence of dimethyl acetylenedicarboxylate and benzyl bromide/phenylacetylene.

Subnanometer Topological Tuning of the Liquid Intrusion/Extrusion Characteristics of Hydrophobic Micropores.

Intrusion (wetting)/extrusion (drying) of liquids in/from lyophobic nanoporous systems is key in many fields, including chromatography, nanofluidics, biology, and energy materials. Here we demonstrate that secondary topological features decorating main channels of porous systems dramatically affect the intrusion/extrusion cycle. These secondary features, allowing an unexpected bridging with liquid in the surrounding domains, stabilize the water stream intruding a micropore. This reduces the intrusion/extrusion barrier and the corresponding pressures without altering other properties of the system. Tuning the intrusion/extrusion pressures via subnanometric topological features represents a yet unexplored strategy for designing hydrophobic micropores. Though energy is not the only field of application, here we show that the proposed tuning approach may bring 20–75 MPa of intrusion/extrusion pressure increase, expanding the applicability of hydrophobic microporous materials.

Matthias Bel and the Russian Academic Milieu during the Enlightenment

Since the 1950s the Czech, Slovak, and Hungarian scholars have carried out research aimed at analysing the personal correspondence of Matthias Bel, a Hungarian polymath and one of the most significant intellectuals of the first half of the 18th century in the Habsburg monarchy. Analysis of Bel’s letters has revealed many interesting facts about Bel’s life as a Baroque scholar. It has also brought to light the sphere of his collaborations with various colleagues, both domestic and foreign ones. Amongst Bel’s contacts, there were also German scientists from the St Petersburg Academy of Sciences, most importantly, Gottlieb Siegfried Bayer and Christian Goldbach. With the recent emergence of the projects supporting the publication of the bilingual Latin-Slovak translations of Bel’s major work Notitia Hungariae novae historico geographica, historians have been seeking for to widen a range of its possible interpretations or to compare Bel’s opus magnum with similar works of his contemporaries. The study thus focuses on the analysis of a trace, which Bel’s communication left in the Russian historical milieu in the first half of the 18th century. On the basis of historical sources, and with corresponding relevant scholarship, a connection with Vasilii Nikitich Tatishchev’s work Istoriia rossiiskaia is outlined. With Bayer being in contact with both Bel and Tatishchev, a rather unexpected bridge was built between the Hungarian and Russian science in the era of the early Enlightenment. The aim of the study is to introduce new, and yet unpublished discoveries about the work of Matthias Bel and Vasilii Nikitich Tatishchev.

Front Cover: Unveiling the Unique Roles of Metal Coordination and Modulator in the Polymorphism Control of Metal‐Organic Frameworks (Chem. Eur. J. 70/2021)

The extraordinary coordination versatility of the Th4+ cation and the unexpected bridging role of formate allows polymorphism control of thorium–organic frameworks (TOFs) with five distinct phases, wherein the highest degree of porosity and interpenetration for TOFs have been achieved. More information can be found in the Full Paper by J. Lin et al. (DOI: 10.1002/chem.202103062).

Genetic Algorithm-Markovian Model for Predictive Bridge Asset Management

Abstract Rapid or unexpected bridge deterioration can lead to partial collapse, which can subsequently hinder transportation activities and result in economic and human losses. Heavily adopted by t...

Early warning system for the detection of unexpected bridge displacements from radar satellite data

Several hundred satellites are monitoring our planet every day, some of which are able to measure subtle ground movement. Satellites that carry synthetic aperture radar (SAR) sensors are capable of providing high-resolution weather-independent imagery of the Earth. By taking several images of an area of interest at different times and analyzing them with advanced processing techniques such as interferometric SAR (InSAR), millimeter-level motion on ground structures can be detected and measured. Ground motion maps have been validated for several scenarios over the past 20 years utilizing Earth Observation (EO) technology. This paper presents InSAR basics and the methodology to apply this mature EO technology to bridges with a focus on the interpretation and validation of satellite data and their use for 3D visualization and early warning of unexpected bridge displacements. The concept of thermal sensitivity and its use to monitor bridge behavior is introduced. Two case studies are provided to illustrate and validate the application, and specific calculation methods are proposed to determine the extent of thermal movement for given types of bridges. Finally, a new 3D visualization tool that incorporates processed satellite data is briefly presented, which will serve in future development phases as a platform for bridge movement assessment and early warning to identify and flag abnormal bridge displacements, and to help avoid failures.

The bridge piers sagging problem under permafrost subbase degradation conditions and the possible solution

Permafrost soils are common for extensive areas of our country and when building engineering structures in such conditions, it is necessary to take into account the factor supporting subbase on the permafrost soil, which may initially have high stress-related characteristics. But the permafrost degradation phenomenon with frost retreat no less common. It can be happening both for natural reasons due to global warming, and for man-made reasons, when interference during construction and further the structure itself initiates subsoil frost retreat. For the most part, permafrost soils lose their strength and elastic properties during the frost retreat, turning into an almost liquid consistency, which entails the failure of the supports in the bearing capability and position stability. With the road network development and the bridge’s construction in the northern regions at the end of the 60s — early 70s of the XX century, the first principle of the design was widely applied. It was for use and maintenance of the subsoil in a frozen state, which means not require a deep foundation required. However, after 20 — 30 years of operation, cases of unexpected and significant bridge piers sagging began to be noted, as it turned out, was the result of permafrost soils frost retreat to the entire depth of the foundation. It was also noted that in some cases the bridge piers sagging is preceded by its frost boil phenomena, which appear shortly before piers sinking and almost complete failure. In this article case of an unexpected bridge piers failure examined on a specific bridge. After 30 years of proper functioning, pierces received such significant sagging, so in just three years that got to the point when it’s not only traffic safety but the cohesiveness of the entire structure. And before that, a frost boil was noted at some of the bridge pierce. The purpose of this study is to analyze the frost boil mechanism and sagging of the bridge pierce’ foundations due to the progressive permafrost degradation and to suggest restoring and maintaining ways for pierces’ operation capacity. Overall, the reasons and principles of permafrost subbase degradation were analyzed in this paper. through calculations using a specific example, significant sagging and bridge pierce bearing capability loss observations were justified and substantiated the effectiveness of the proposed in this article structural reinforcement measures.

Resisting Broken Windows

Concurrent housing and opioid crises have increased exposure to street-crime, homelessness and addiction in American cities. What are the political consequences of this increased neighborhood disorder? We examine a change in social context following the relocation of homelessness and drug treatment services in Boston. In 2014, an unexpected bridge closing forced nearly 1000 people receiving emergency shelter or addiction treatment to relocate from an island in the Boston Harbor to mainland Boston, causing sustained increases in drug-use, loitering, and other features of neighborhood disorder. Residents near the relocation facilities mobilized to maintain order in their community. In the subsequent Mayoral election, their turnout grew 9% points while participation in state and national elections was unchanged. However, increased turnout favored the incumbent Mayor, consistent with voter learning about candidate quality following local shocks. Voters responded to neighborhood changes at the relevant electoral scale and rewarded responsive politicians.

Calibration Method for Dynamic Deflection Measurement of Bridges by Photogrammetry

Heavy vehicular traffic and aggressive environmental conditions can cause unexpected bridge deterioration, thus, periodic inspections to identify and assess possible defects are required. One indicator is the amount of vertical deflection that occurs during loading. Some different types of transducers can be used to measure the deflection. One of them is the photogrammetry. It is a typical noncontact measurement method. Unfortunately, it is difficult to calibrate this type of instruments. The key point is the evaluation of the dynamic deflection measurement capability. A dynamic calibration system of bridge photogrammetric measurement system was composed of the motorized linear stage, LED target and computer. The Fréchet distance was used as a model to evaluate the dynamic deflection measurement capability of bridge deflection photogrammetry. The photogrammetric bridge deflection measuring instruments are products of BIOET, which are used to carry out the measurement experiment. The results show that this system can calibrate the dynamic deflection measurement error of photogrammetric bridge deflection measuring instruments. Fréchet distance can reflect the relationship between the curves. This evaluation method is more accurate than the current evaluation method based on the error of indication of maximum dynamic deflection.

An unexpected bridge between chemical bonding indicators and electrical conductivity through the localization tensor.

While the modern theory of the insulating state shows that the conducting or insulating properties of a system can be extracted solely from the ground state properties via the so-called localization tensor (LT), no chemical reading of this important quantity has ever been offered. Here, a remarkable link between the LT and the bond orders as described by the delocalization indices (DIs) of chemical bonding theory is reported. This is achieved through a real space partition of the LT into intra- and interatomic contributions. We show that the convergence or divergence of the LT in the thermodynamic limit, which signals the insulating or conducting nature of an extended system, respectively, can be nailed down to DIs. This allows for the exploitation of traditional chemical intuition to identify essential and spectator atomic groups in determining electrical conductivity. The thermodynamic limit of the LT is controlled by the spatial decay rate of the interatomic DIs, exponential in insulators and power-law in conductors. Computational data of a few selected toy systems corroborate our results.

Structural monitoring of movable bridge mechanical components for maintenance decision-making

This paper presents a unique study of Structural Health Monitoring (SHM) for the maintenance decision making about a real life movable bridge. The mechanical components of movable bridges are maintained on a scheduled basis. However, it is desired to have a condition-based maintenance by taking advantage of SHM. The main objective is to track the operation of a gearbox and a rack-pinion/open gear assembly, which are critical parts of bascule type movable bridges. Maintenance needs that may lead to major damage to these components needs to be identified and diagnosed timely since an early detection of faults may help avoid unexpected bridge closures or costly repairs. The fault prediction of the gearbox and rack-pinion/open gear is carried out using two types of Artificial Neural Networks (ANNs): 1) Multi-Layer Perceptron Neural Networks (MLP-NNs) and 2) Fuzzy Neural Networks (FNNs). Monitoring data is collected during regular opening and closing of the bridge as well as during artificially induced reversible damage conditions. Several statistical parameters are extracted from the time-domain vibration signals as characteristic features to be fed to the ANNs for constructing the MLP-NNs and FNNs independently. The required training and testing sets are obtained by processing the acceleration data for both damaged and undamaged condition of the aforementioned mechanical components. The performances of the developed ANNs are first evaluated using unseen test sets. Second, the selected networks are used for long-term condition evaluation of the rack-pinion/open gear of the movable bridge. It is shown that the vibration monitoring data with selected statistical parameters and particular network architectures give successful results to predict the undamaged and damaged condition of the bridge. It is also observed that the MLP-NNs performed better than the FNNs in the presented case. The successful results indicate that ANNs are promising tools for maintenance monitoring of movable bridge components and it is also shown that the ANN results can be employed in simple approach for day-to-day operation and maintenance of movable bridges.

An Electron-Rich Molybdenum-Molybdenum Quintuple Bond Spanned by One Lithium Atom

Take five: A unique quintuply bonded dimolybdenum complex [Mo(2)(μ-Li){μ-HC(N-2,6-Et(2)C(6)H(3))(2)}(3)] (see picture) was synthesized and characterized. The Mo-Mo interaction includes an unexpected bridging Li(+) ion. Calculations indicate the bridging Li(+) ion does not perturb the Mo-Mo bond length (2.0612(4) Å), but results in a relatively small effective Mo-Mo bond order of 3.67.

Estimating Route Choice and Travel Time Reliability with Field Observations of Bluetooth Probe Vehicles

Route choice is often assessed with either a modeling technique or field observations. Field observations have historically used a variation of license plate matching. The proposed technique assesses route choice and travel time that uses an anonymous Bluetooth media access control (MAC) address sampling technique as a surrogate for license plate matching to assess route choice. The Bluetooth sampling technique was used to evaluate the impact of an unexpected bridge closure in northwest Indiana, including an assessment of the proportion of vehicles using each of four alternate routes. The Bluetooth technology also provided a means to collect travel time data for each alternate route; these observed travel times were also compared with travel time estimates obtained by route classification and link distance. In general, the route choice behavior was consistent with observed travel time estimates. The Bluetooth sampling technique is cost-effective to deploy, and although results are approximate, direct measurement of travel times and route choice is useful for public agencies to assess mobility and travel time reliability along alternate routes.

Density Functional Theory Study of the Reaction Mechanism for Competitive Carbon−Hydrogen and Carbon−Halogen Bond Activations Catalyzed by Transition Metal Complexes

Carbon-hydrogen and carbon-halogen bond activations between halobenzenes and metal centers were studied by density functional theory with the nonempirical meta-GGA Tao-Perdew-Staroverov-Scuseria functional and an all-electron correlation-consistent polarized valence double-zeta basis set. Our calculations demonstrate that the hydrogen on the metal center and halogen in halobenzene could exchange directly through a kite-shaped transition state. Transition states with this structure were previously predicted to have high energy barriers (J. Am. Chem. Soc. 2005, 127, 279), and this prediction misled others in proposing a mechanism for their recent experimental study (J. Am. Chem. Soc. 2006, 128, 3303). Furthermore, other halo-carbon activation pathways were found in the detailed mechanism for the competitive reactions between cationic titanium hydride complex [Cp*((t)Bu(3)P=N)TiH](+) and chlorobenzene under different pressure of H(2). These pathways include the ortho-C-H and Ti-H bond activations for the formation and release of H(2) and the indirect C-Cl bond activation via beta-halogen elimination for the movement of the C(6)H(4) ring and the formation of a C-N bond in the observed final product. A new stable isomer of the observed product with a similar total energy and an unexpected bridging between the Cp* ring and the metal center by a phenyl ring is also predicted.

Adiponectin and Adaptive Immunity

See related article, pages 218–225 Obesity, characterized by an excess of adipose tissue mass, is closely associated with an increase in cardiovascular morbidity and mortality attributable to atherosclerosis.1 Obesity is a major underlying risk factor for atherosclerosis through other well-known risk factors, including the major risk factors (hypercholesterolemia, hypertension, hyperglycemia) and emerging risk factors (atherogenic dyslipidemia, insulin resistance, proinflammatory and prothrombotic state).2 The clinical value of novel risk factors such as high-sensitivity C-reactive protein are currently subject of ongoing discussions.3 The clustering of major and emerging risk factors that is found in most obese patients is defined as the metabolic syndrome.2 Among various cytokine-like hormones secreted by adipose tissue, the most abundant and adipose-specific is adiponectin (Figure).4 Reduced plasma levels of adiponectin, which are found in obese patients, are closely associated with obesity-related diseases, including atherosclerotic cardiovascular diseases, type 2 diabetes, hypertension, and dyslipidemia.4 Emerging experimental evidence indicates that adiponectin mediates antiatherogenic and antithrombotic effects through direct protective actions on endothelial cells, smooth muscle cells, macrophages, and platelets.1,5,6 Figure. Antiatherogenic effects of adiponectin. The cytokine-like hormone adiponectin, which is selectively expressed by adipose cells, exhibits antiatherogenic properties through direct and indirect effects on endothelial cells (EC), smooth muscle cells (SMC), platelets, macrophages, and T lymphocytes. IL indicates interleukin; IL-1RA, IL-1 receptor antagonist; NF-κB, nuclear factor κB. …

Graphene: New bridge between condensed matter physics and quantum electrodynamics

Graphene is the first example of truly two-dimensional crystals—it is just one layer of carbon atoms. It turns out to be a gapless semiconductor with unique electronic properties resulting from the fact that charge carriers in graphene demonstrate charge-conjugation symmetry between electrons and holes and possess an internal degree of freedom similar to “chirality” for ultrarelativistic elementary particles. It provides an unexpected bridge between condensed matter physics and quantum electrodynamics (QED). In particular, the relativistic Zitterbewegung leads to the minimum conductivity of the order of conductance quantum e 2 / h in the limit of zero doping; the concept of Klein paradox (tunneling of relativistic particles) provides an essential insight into electron propagation through potential barriers; vacuum polarization around charge impurities is essential for understanding of high electron mobility in graphene; an index theorem explains the anomalous quantum Hall effect.

Time-Dependent Behavior of a Concrete Integral Abutment Bridge

Time-dependent behavior of an integral abutment bridge near Rochester, Minnesota, was investigated from the beginning of construction through 7 years of service by using field data collected from more than 150 instruments installed in the bridge during construction. Long-term bridge shortening was observed from the readings of horizontal extensometers installed behind the abutments. Measured pile curvatures steadily increased with time. To understand this unexpected bridge behavior better, a time-dependent numerical study using the creep and shrinkage models from American Concrete Institute Committee 209 was conducted. The results obtained in this research indicate that concrete creep and shrinkage had a significant effect on the behavior of the concrete integral abutment bridge over the course of the 7-year study.

Three new modes of adenine-copper(II) coordination: interligand interactions controlling the selective N3-, N7- and bridging μ-N3,N7-metal-bonding of adenine to different N-substituted iminodiacetato-copper(II) chelates

The reaction of Cu2CO3(OH)2, various N-substituted-iminodiacetic acids [R-N(CH2CO2H)2)] and adenine (AdeH) in water yields crystalline samples of mixed-ligand copper(II) complexes of formulas [Cu(A)(N7-AdeH)(H2O)]·H2O (A=N-methyl- or N-ethyl-iminodiacetato(2−); compounds 1 and 2, respectively), [Cu(B)(N3-AdeH)(H2O)]·H2O (B=N-benzyl- or N-(p-methylbenzyl)-iminodiacetato(2−); compounds 3 and 4, respectively) as well as [Cu4(pheida)4(μ-N3,N7-AdeH)2(H2O)4]·2H2O (pheida=N-phenethyl-iminodiacetato(2−)). Crystal structures of the acid H2pheida and compounds 1–5 are reported. H2pheida acid exhibits a typical zwitterionic structure. Copper(II) compounds were also studied by TG analysis (with FT-IR study of the evolved gasses), IR, electronic and ESR spectra and magnetic susceptibility data. The N-alkyl- or N-benzyl-like-iminodiacetato(2−) ligands (A or B) give complexes with Cu(II)/(A or B)/AdeH equimolar ratio, whereas pheida yields an unexpected tetranuclear compound with a 2:2:1 Cu(II)/pheida/AdeH molar ratio. In 1 and 2 AdeH binds to the metal by N7, whereas in 3 and 4 the N3 atom is used. An unexpected bridging μ-N3,N7-AdeH-dicopper(II) binding mode is found in the tetra-nuclear compound 5 (without interligand π,π-stacking interactions). These AdeH-Cu(II) binding modes have not been referred in the literature before. The difference in AdeH-Cu(II) binding modes in compounds 1 or 2 and 3 or 4 is rationalised on the basis of the absence or presence of a flexible N-benzyl-like substituent in the iminodiacetato(2−) ligand skeleton, which prevents or permits the interligand π,π-stacking interactions.

A magneto-structural correlation between the Heisenberg constant, J, and the MnOMn angle in [Mn IV(μ-O)] 2 dimers

In our ongoing studies of high valent manganese dimers of the general formula [Mn IV(Schiff base)(μ-O)] 2 as models for the oxygen evolving complex (OEC) of photosystem II (PSII), we now report several new Mn complexes that allow us to define a magneto-structural correlation between the Heisenberg exchange constant, J, from the Heisenberg exchange equation ( H=−2 J[S 1 · S 2]) and the MnOMn angle of the [Mn IV(μ-O)] 2 core. The new and unique structures of [Mn IV(3,5-di- t-busalpn)(μ-O)] 2 ( 2) and [Mn IV(μ-3,5-di-Cl-salpn)(μ-O)] 2 ( 3) exhibit unexpected structures compared with those of [Mn IV(salpn)(μ-O)] 2 ( 1) (H 2(salpn)= N, N′-bis(salicylideneimino)-1,3-diaminopropane). The structure of 2, unlike that of 1, does not have a molecular inversion center due to a ‘rotation’ of one ligand. Instead, there exists a pseudo-C 2 axis through the oxo bridges of the [Mn IV(μ-O)] 2 core. The MnMn distance of 2 is 2.7753(8) Å and that of 3 is 2.7430(8) Å. The 3,5-di-Cl-salpn 2− ligand of 3 adopts an unexpected bridging mode between the manganese ions. The magneto-structural correlation is valid for these new Schiff base complexes and other non-Schiff base containing compounds. The J values range over 110 cm −1 versus a MnOMn range of 3.9°. The data imply that a ferromagnetically coupled [Mn IV(μ-O)] 2 would be unlikely to occur in the OEC, wherein such may be invoked to generate an S=5/2 ground state for the g=4.1 EPR signal observed in the S 2 state.

The dimension subgroup problem

Whether the terms of the lower central series of a group are associated with the powers of the augmentation ideal of its integral group ring is a question which has been open for over thirty years. This question, the dimension subgroup problem, has achieved notoriety for the number of false proofs it has elicited. In this paper, we record general observations on the problem, verify the conjecture for several new classes of groups and develop generalizations which indicate new lines of research. In a subsequent paper [20], we examine the subgroups attached to group rings over arbitrary coefficient domains. The general properties of dimension subgroups are set forth in the first section. Several equivalent formulations of the conjecture are given. The subgroups are calculated in a number of special cases. A minimal counterexample is a finite p-group with cyclic center. In the second section, we take the approach that such reductions make available. The conjecture is established for Abelian-by-cyclic groups and for split extensions of Abelian groups by groups satisfying the conjecture; it follows inductively that the Sylow subgroups of the symmetric groups satisfy the problem and so every p-group embeds in a p-group for which the conjecture is verified. This analysis provides an unexpected bridge to the work of Passi who conjectured a strong result about the properties of factor sets of extensions of divisible groups byp-groups and showed how it would establish the dimension subgroup conjecture. Here another way of using Passi’s conjecture to solve the problem is introduced and applied in a minimal counterexample to obtain new results. The third section places the problem in a wider context: I f G, is associated with I”, then G, is associated with even larger ideals. It may be that these ideals will have to be identified before the dimension subgroup problem can be resolved affirmatively. Some such ideals are discovered by expanding the methods of Passi and Moran. The results obtained are used to establish the