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Fabricating new and efficient materials aimed at containment of water contamination, in particular removing toxic heavy metal based oxo‐anions (e. g. CrO42−, TcO4−) holds paramount importance. In this work, we report two new highly stable imidazolium based ionic porous organic polymers (iPOPs) decorated with multiple interaction sites along with electrostatics driven adsorptive removal of such oxo‐anions from water. Both the iPOPs (namely, iPOP‐3 and iPOP‐4) exhibited rapid sieving kinetics and very high saturation uptake capacity for CrO42− anions (170 and 141 mg g−1 for iPOP‐3 and iPOP‐4 respectively) and ReO4− (515.5 and 350.3 mg g−1 for iPOP‐3 and iPOP‐4 respectively), where ReO4− anions being the non‐radioactive surrogative counterpart of radioactive TcO4− ions. Noticeably, both iPOPs showed exceptional selectivity towards CrO42− and ReO4− even in presence of several other concurrent anions such as Br−, Cl−, SO42−, NO3− etc. The theoretical binding energy calculations via DFT method further confirmed the preferential interaction sites as well as binding energies of both iPOPs towards CrO42− and ReO4− over all other competing anions which corroborates with the experimental high capacity and selectivity of iPOPs toward such oxo‐anions. [ABSTRACT FROM AUTHOR]

Graphical abstract A post-synthetically modified MOF has been employed for sensing of bisulfite anion in water medium. This MOF based selective turn on response towards bisulfite anion has also been demonstrated in presence of concurrent anions. Abstract A metal–organic framework (MOF) based luminescent probe was strategically designed for selective recognition of bisulfite anion (HSO 3 −) in water medium. The chemically stable MOF, NH 2 -MIL-68(In) was decorated with specific recognition site via post synthetic modification. The post synthetically modified MOF showed a selective turn on response towards bisulfite anion retaining its structural integrity. This selective recognition is also persistent even in presence of competing anions. [ABSTRACT FROM AUTHOR]

In the protection scheme of fault management in a WDM optical network, corresponding to every source-destination path used for data transmission, a backup path is maintained in a stand-by mode. In the case of a failure (either due to a fiber cut or due to equipment failure) in the primary path, data transmission is quickly switched to the backup path. In order to tolerate any single fault, the backup path must be edge (or node) disjoint from the primary path. Most often a shortest path between the source and the destination is chosen as the primary path. To obtain a link (node) disjoint backup (or secondary) path, the links (nodes) of the primary path are removed from the graph and then a shortest path in the modified graph is chosen as the backup path. The attractive feature of this scheme is its simplicity. However, the scheme has a severe drawback. Due to the choice of a shortest path as the primary path, the length of a link disjoint secondary path may be unacceptably large. In this paper, we propose a novel way of choosing the primary and the secondary paths so that the lengths of both the paths are small. Unfortunately, the problem of choosing primary and secondary paths in this way turns out to be NP-complete. We provide the NP-completeness proof of both the edge disjoint and the node disjoint version of the problem. We provide an approximation algorithm for the problem with a guaranteed performance bound of 2 and a mathematical programming formulation for the exact solution of the problem. Though the approximate solution provides a performance bound of 2, through extensive experimental evaluation, we find that the approximate solution is very close to the optimal solution and the ratio between the approximate to the optimal solution never exceeds 1.2. Although we discuss the single fault scenario in this paper, the algorithms discussed here, can be used equally effectively for the multiple fault scenario also. Finally, we discuss other variations o... [ABSTRACT FROM AUTHOR]

We study geometric variations of the discriminating code problem. In the discrete version of the problem, a finite set of points P and a finite set of objects S are given in R d . The objective is to choose a subset S ∗ ⊆ S of minimum cardinality such that for each point p i ∈ P , the subset S i ∗ ⊆ S ∗ covering p i satisfies S i ∗ ≠ ∅ , and each pair p i , p j ∈ P , i ≠ j , we have S i ∗ ≠ S j ∗ . In the continuous version of the problem, the solution set S ∗ can be chosen freely among a (potentially infinite) class of allowed geometric objects. In the 1-dimensional case ( d = 1 ), the points in P are placed on a horizontal line L, and the objects in S are finite-length line segments aligned with L (called intervals). We show that the discrete version of this problem is NP-complete. This is somewhat surprising as the continuous version is known to be polynomial-time solvable. This is also in contrast with most geometric covering problems, which are usually polynomial-time solvable in one dimension. Still for the 1-dimensional discrete version, we design a polynomial-time 2-approximation algorithm. We also design a PTAS for both discrete and continuous versions in one dimension, for the restriction where the intervals are all required to have the same length. We then study the 2-dimensional case ( d = 2 ) for axis-parallel unit square objects. We show that both continuous and discrete versions are NP-complete, and design polynomial-time approximation algorithms that produce (16 · O P T + 1) -approximate and (64 · O P T + 1) -approximate solutions respectively, using rounding of suitably defined integer linear programming problems. Finally, we apply our techniques to a related variant of the discrete problem, where instead of points and geometric objects we just have a set S of objects. The goal is to select a small subset S ∗ of objects so that all objects of S are discriminated by their intersection with the objects of S ∗ . This problem can be viewed as a graph problem by stating it in terms of the vertices of the geometric intersection graph of S. Under this graph-theoretical form, it is known as the identifying code problem. We show that the identifying code problem for axis-parallel unit square intersection graphs (in d = 2 ) can be solved in the same manner as for the discrete version of the discriminating code problem for unit square objects described above, and all our positive approximation results still hold in this setting. [ABSTRACT FROM AUTHOR]

Large‐scale nuclear power plant production of iodine radionuclides (129I, 131I) pose huge threat in the events of nuclear disaster. Effective removal of radioiodine from nuclear waste is one of the most critical challenge because of the drawbacks of state‐of‐the‐art adsorbents such as high cost, low uptake capacity and non‐recyclability. Herein, two hydroxy‐functionalized (‐OH) hypercrosslinked polymers (HCPs), namely HCP‐91 and HCP‐92, have been synthesized and employed towards capture of iodine. High chemical stability along with synergistic harmony of high porosity and functionality of these materials makes them suitable candidates for capture of iodine from both vapor phase and water medium. Moreover, both the HCPs showed superior iodine removal performance from water in terms of fast kinetics and high removal efficiency (2.9 g g−1 and 2.49 g g−1 for HCP‐91 and HCP‐92 respectively). The role of functionality (‐OH groups) and porosity has been established with the help of HCP‐91, HCP‐92 and non‐functionalized biphenyl HCP for the efficient capture of I3− ions from water. In addition, both HCPs exhibited excellent selectivity and recyclability towards triiodide ions, rendering the potential of these materials towards real‐time applications. Lastly, Density functional theoretical studies revealed key insights and corroborate well with the experimental findings. [ABSTRACT FROM AUTHOR]

In this paper, we study the problem of mobile target tracking using the fewest number of mobile trackers for two different types of targets. Given the target trajectories and the period of observation, we propose techniques to compute the minimum number of trackers and their trajectories required to track all mobile targets. Two classes of mobile targets are considered in this paper: 1) targets that need tracking for the entire duration of observation and 2) targets that need tracking at least once during the period of observation. We show that even when target trajectories are known in advance, the problem is computationally hard, i.e., NP-complete. We formulate the problem as a network flow problem and propose algorithms for its solution. We evaluate the performance of our algorithms through simulation and study the impact of parameters such as the speed and sensing range of the trackers. [ABSTRACT FROM AUTHOR]

Two porous hydrogen-bonded organic frameworks (HOFs) based on arene sulfonates and guanidinium ions are reported. As a result of the presence of ionic backbones appended with protonic source, the compounds exhibit ultra-high proton conduction values ( σ) 0.75× 10−2 S cm−1 and 1.8×10−2 S cm−1 under humidified conditions. Also, they have very low activation energy values and the highest proton conductivity at ambient conditions (low humidity and at moderate temperature) among porous crystalline materials, such as metal-organic frameworks (MOFs) and covalent organic frameworks (COFs). These values are not only comparable to the conventionally used proton exchange membranes, such as Nafion used in fuel cell technologies, but is also the highest value reported in organic-based porous architectures. Notably, this report inaugurates the usage of crystalline hydrogen-bonded porous organic frameworks as solid-state proton conducting materials. [ABSTRACT FROM AUTHOR]

Two porous hydrogen-bonded organic frameworks (HOFs) based on arene sulfonates and guanidinium ions are reported. As a result of the presence of ionic backbones appended with protonic source, the compounds exhibit ultra-high proton conduction values ( σ) 0.75× 10−2 S cm−1 and 1.8×10−2 S cm−1 under humidified conditions. Also, they have very low activation energy values and the highest proton conductivity at ambient conditions (low humidity and at moderate temperature) among porous crystalline materials, such as metal-organic frameworks (MOFs) and covalent organic frameworks (COFs). These values are not only comparable to the conventionally used proton exchange membranes, such as Nafion used in fuel cell technologies, but is also the highest value reported in organic-based porous architectures. Notably, this report inaugurates the usage of crystalline hydrogen-bonded porous organic frameworks as solid-state proton conducting materials. [ABSTRACT FROM AUTHOR]

Keywords: anions; DFT calculations; dual capture; hyper-cross-linked polymers; radioiodine; water remediation EN anions DFT calculations dual capture hyper-cross-linked polymers radioiodine water remediation 1 1 1 11/29/22 20221101 NES 221101 B The cover feature image illustrates b a family of hydroxy-functionalized hypercrosslinked polymers (HCPs) toward efficient capture of radioactive iodine from both vapour and water phase. Anions, DFT calculations, dual capture, hyper-cross-linked polymers, radioiodine, water remediation Cover Feature: Hydroxy-Functionalized Hypercrosslinked Polymers (HCPs) as Dual Phase Radioactive Iodine Scavengers: Synergy of Porosity and Functionality (ChemPlusChem 11/2022). [Extracted from the article]