In Situ Synthesis of Surface-Mounted Novel Nickel(II) Trimer-Based MOF on Nickel Oxide Hydroxide Heterostructures for Enhanced Methanol Electro-Oxidation

Engineering the heterogeneous interface fusing MOFs and inorganic active component is an effective strategy to improve the electrochemical performance. Herein, we report a new Ni3-based MOF (denoted as CTGU-24) with an infrequent two-fold interpenetrating 3D (3,8)-connected network constructed from Ni(II) trimer and mixed tripodal tectonics for the electrocatalytic methanol oxidation reaction (MOR). In order to improve its stability and activities, the heterogeneous hybrid CTGU-24@NiOOH has been fabricated successfully via the first preparation of the NiOOH nanosphere and then in situ formation of CTGU-24 decorated on the NiOOH surface. Moreover, the integration of CTGU-24@NiOOH and different additives [acetylene black (AB) and ketjen black (KB)], resulting in the optimized hybrid sample AB&CTGU-24@NiOOH (4:4). It attains better MOR performance with an area-specific peak current density of 34.53 mA·cm−2 than pure CTGU-24 (14.99 mA·cm−2) and improved durability in an alkali medium. The new findings indicate that the CTGU-24@NiOOH heterostructure formed in situ and the integration of moderate additives are critical to optimizing and improving electrocatalytic activity of pure MOF crystalline material.

Development of Graphene-Doped TiO2-Nanotube Array-Based MIM-Structured Sensors and Its Application for Methanol Sensing at Room Temperature

This work concerns the development of a good quality graphene doped TiO2 nanotube array sensor for efficient detection of methanol. A pure and graphene doped TiO2 nanotube array was synthesized by electrochemical anodization. Morphological, structural and optical characterizations were performed to study the samples. Both the nanotube samples were produced in Au/TiO2 nanotube/Ti type MIM-structured devices. Pure and graphene-doped TiO2 nanotubes offered a response magnitude of 20% and 28% to 100 ppm of methanol at room temperature, respectively. Response/Recovery time was fast for the graphene doped TiO2 nanotube array (34 s/40 s) compared to a pure TiO2 nanotube array (116 s/576 s) at room temperature. This study confirmed the notable enhancement in methanol sensing due to the formation of local heterojunctions between graphene and TiO2 in the hybrid sample.

Production of an Efficient Magnetic Adsorbent From Babassu Coconut Endocarp and Ni Particles for Easy Dye Removal From Mimetic Contaminated Effluents

Ni metal particles, with sizes ranging from 70 to 110 nm, dispersed in activated carbon produced from the babassu coconut endocarp (BAC) were successfully synthesized and evaluated by scanning electron microscopy, dispersive energy X-ray spectroscopy, flame atomic absorption spectroscopy and powder X-ray diffraction. These hybrid BACNi-X materials (where X is the Ni / BAC ratio, equal to 10, 20 or 30) exhibit crystalline Ni particles with suitable magnetic properties, shown by increased saturation magnetization and a gradual reduction in coercive fields (varying 80 to 150 Oe) as the Ni content increases. Relatively large values ​​of pore volume (in the range of 0.28-0.37 cm3/g), specific surface area (560-740 m2/g) are achieved, favoring their applications for magnetic remediation of mimetic contaminated effluents. All hybrid samples were tested positively for the adsorption of methylene blue in contaminated synthetic effluents and the greatest removal was achieved by the hybrid sample BACNi-10, which has the largest specific area and reasonable magnetic properties that allowed the manipulation of the sample by an external field.

Tribological and aging behavior of hybrid Al 7075 composite reinforced with B4C, SiC, and TiB2

In this study, B4C+SiC/B4C +TiB2/SiC+TiB2 hybrid reinforcements were added to Al 7075 matrix via the powder metallurgy method. The powders were subjected to mechanical grinding for 240 min, as shown in the graphical abstract. The hybrid composite powder structure produced by the mechanical grinding was then placed in a vertical casting chamber and molten Al 7075 (main matrix) was added to obtain the samples. Samples were dissolved for 1 h at 480 ?C, and then aged at 120 ?C in 4-h increments (32 h in total). After the aging process, the wear behavior of the samples was investigated. In the study, FESEM images were examined for microstructural analysis, and hardness plots of the aged samples were created depending on the time after the solutioning treatment. The friction coefficient, volume loss, and worn surface images were investigated to determine the wear behavior of the hybrid structures. Results showed that the increased reinforcement rate and the reinforcement size and type directly affected the hardness and wear behavior. In the experiments, the highest hardness and wear resistance behavior were obtained in the hybrid sample of 3% B4C + 3% SiC after 12 h of aging.

Effect of Stacking Sequences on Mechanical Properties of Kenaf Hybrid Composites

In the current project, Kenaf fiber (K) and carbon fiber (C) with epoxy resin were utilized to form carbon-kenaf hybrid composites using a vacuum infusion technique. The volume fraction of fiber and thickness of a hybrid composite was fixed at 40 vol.% and 3mm, respectively. Four different sequences were introduced in the current project including CCCCC, KKKKK, KCKCK, and CKCKC. Mechanical testing such as tensile and flexural tests were performed according to ASTM D3039 and ASTM D790, respectively. Scanning Electron Microscope (SEM) and Optical Microscope (OM) were used to identify modes of failures in both tensile and flexural tests of carbon/kenaf hybrid composites. The hybrid CKCKC sample displayed a higher value in tensile strength (264.23 MPa), tensile modulus (11.06 GPa), flexural strength (438.51 MPa) and flexural modulus (25.13 GPa) as compared than KCKCK hybrid sample.

Spectral attributes of sub-amorphous thermal conductivity in cross-linked organic–inorganic hybrids

Comparison of thermal conductivity in hybrid and pristine inorganic models and the modal spectrum of each sample showing the approximately unchanged number of propagating modes and a significant number of added localized modes in the hybrid sample.

Multiquery Motion Planning in Uncertain Spaces: Incremental Adaptive Randomized Roadmaps

Sampling-based motion planning is a powerful tool in solving the motion planning problem for a variety of different robotic platforms. As its application domains grow, more complicated planning problems arise that challenge the functionality of these planners. One of the main challenges in the implementation of a sampling-based planner is its weak performance when reacting to uncertainty in robot motion, obstacles motion, and sensing noise. In this paper, a multi-query sampling-based planner is presented based on the optimal probabilistic roadmaps algorithm that employs a hybrid sample classification and graph adjustment strategy to handle diverse types of planning uncertainty such as sensing noise, unknown static and dynamic obstacles and an inaccurate environment map in a discrete-time system. The proposed method starts by storing the collision-free generated samples in a matrix-grid structure. Using the resulting grid structure makes it computationally cheap to search and find samples in a specific region. As soon as the robot senses an obstacle during the execution of the initial plan, the occupied grid cells are detected, relevant samples are selected, and in-collision vertices are removed within the vision range of the robot. Furthermore, a second layer of nodes connected to the current direct neighbors are checked against collision, which gives the planner more time to react to uncertainty before getting too close to an obstacle. The simulation results for problems with various sources of uncertainty show a significant improvement compared with similar algorithms in terms of the failure rate, the processing time and the minimum distance from obstacles. The planner is also successfully implemented and tested on a TurtleBot in four different scenarios with uncertainty.

Exploring Influence of Sampling Strategies on Event-Based Landslide Susceptibility Modeling

This study explores two modeling issues that may cause uncertainty in landslide susceptibility assessments when different sampling strategies are employed. The first issue is that extracted attributes within a landslide inventory polygon can vary if the sample is obtained from different locations with diverse topographic conditions. The second issue is the mixing problem of landslide inventory that the detection of landslide areas from remotely-sensed data generally includes source and run-out features unless the run-out portion can be removed manually with auxiliary data. To this end, different statistical sampling strategies and the run-out influence on random forests (RF)-based landslide susceptibility modeling are explored for Typhoon Morakot in 2009 in southern Taiwan. To address the construction of models with an extremely high false alarm error or missing error, this study integrated cost-sensitive analysis with RF to adjust the decision boundary to achieve improvements. Experimental results indicate that, compared with a logistic regression model, RF with the hybrid sample strategy generally performs better, achieving over 80% and 0.7 for the overall accuracy and kappa coefficient, respectively, and higher accuracies can be obtained when the run-out is treated as an independent class or combined with a non-landslide class. Cost-sensitive analysis significantly improved the prediction accuracy from 5% to 10%. Therefore, run-out should be separated from the landslide source and labeled as an individual class when preparing a landslide inventory.

Fish Hybridization Leads to Uncertainty Regarding Ciguatera Fish Poisoning Risk; Confirmation of Hybridization and Ciguatoxin Accumulation with Implications for Stakeholders

Globally, ciguatera fish poisoning (CFP) avoidance efforts rely primarily on local knowledge of the fish being consumed, its collection location, and association with illnesses. In 2016, several fish that appeared to be hybrids between a local commercially prized species, Ocyurus chrysurus, and a regionally prohibited species Lutjanus apodus (due to CFP concerns), were caught nearshore in United States Virgin Islands waters, leading to confusion regarding the safety of consuming the fish. The hybrid status of the fish was verified as O. chrysurus (male) × L. apodus (female) by comparing two sets of gene sequences (mitochondrial CO1 and nuclear S7). Using an in vitro mouse neuroblastoma (N2a) assay, one of the hybrid fish exhibited a composite cytotoxicity of 0.038 ppb Caribbean ciguatoxin-1 (C-CTX-1) equivalents (Eq.); a concentration below the US Food and Drug Administration (FDA) guidance level for safety in fish products for CFP (0.1 ppb C-CTX-1 Eq.) but approximately 2× above the maximum described in the commercially prized parent species (0.019 ppb C-CTX-1 Eq./g). C-CTX-1 was confirmed in the hybrid sample by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The second hybrid fish tested negative for CTXs. This research confirms hybridization between two species with contrasting commercial statuses, discusses CTX accumulation implications for hybridization, and provides a methodology for future studies into novel CFP vectors, with the goal of providing critical information for fishermen and consumers regarding CFP risk management.