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A marine antifouling compound, N-octyl-2-hydroxybenzamide (OHBA), inspired by ceramide and paeonol molecules, was created. First, methyl salicylate was synthesized with salicylic acid and methanol, followed by n-octylamine through an ester-amine condensation reaction. Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and mass spectrometry confirmed the characteristic structure of the OHBA compound. Bioassays showed that OHBA inhibits the growth of typical marine fouling organisms, such as Vibrio azureus, Navicula subminuscula, Ulva pertusa, Mytilus edulis, and Amphibalanus amphitrite, indicating its broad-spectrum antifouling ability. A one-year marine real-sea test further demonstrated the excellent antifouling properties of OHBA. OHBA is also extremely biodegradable, with a half-life of 6.3 days, making it a less environmentally harmful replacement for widely-used heavy metal-containing antifoulants. [ABSTRACT FROM AUTHOR]

Al-CNTs composite coatings were successfully prepared on AZ31 alloy using laser cladding (LC). The effect of TiC nanoparticles on microstructure and corrosion resistance of the LC Al-CNTs and Al-TiC-CNTs composite coatings were investigated. The LC composite coatings were composed of α-Mg solid solution phase and β-Al12Mg17, Mg2Al3, Mg32(Al,Zn)49 and TiC compound phases. A sound metallurgical bonding interface was produced between the LC composite coatings and AZ31 alloy. The surface microhardness and corrosion resistance of the LC composite coatings, which were gradually decreased with increasing the content of carbon nanotubes (CNTs) and TiC nanoparticles, were significantly enhanced compared to those of the AZ31 alloy. The LC Al-CNTs (99 wt% Al + 1 wt% CNTs) composite coating exhibits excellent surface microhardness and corrosion resistance. The mean surface microhardness, self-corrosion potential and self-corrosion current were 266.4 HV, −1.233 V and 2.55 × 10−5 A, which were 426.2%, 78.9% and 16.5% of the AZ31 alloy, respectively. [ABSTRACT FROM AUTHOR]

Polyurethane (PU) and polyurea (PUA) materials have shown significant potential for application in tissue repair. Herein, we design a glycerol ethoxylate (PEG)-based poly(urethane-urea) for bone tissue repair. The polymer precursor was prepared from the reaction of PEG and isophorone diisocyanate (IPDI). The cystine dimethyl ester was used as a cross-linker for the preparation of poly(urethane-urea) elastomers. The material was further strengthened by physical blending of nano-hydroxyapatite (nHA). The physical and biological properties of final material were evaluated by mechanical testing, scanning electron microscopy characterization, degradation tests, cell proliferation and cell differentiation assays. The obtained scaffolds showed good mechanical strength, excellent biocompatibility and osteogenic capability. All the evidences demonstrated that this type of materials has good prospects for bone tissue repair application. [ABSTRACT FROM AUTHOR]

High corrosion resistance Al-Cu powder-reinforced AZ31 Mg-based composites were produced by a laser cladding (LC) and FSP hybrid method. The microstructure characteristics, phase distribution, corrosion performance, and corrosion mechanism were ascertained using SEM, EDS, XRD and an electrochemical workstation. The composite coating of Al-Cu/AZ31 magnesium matrix composite mainly contains α-Mg solid solution, and β-Al12Mg17, AlCu4 and Al2CuMg intermetallic compounds. The intermetallic compounds did not change significantly with the proportion of Al and Cu powders. A large number of pores and microcracks in the composite coating prepared by LC were formed, whereas a sound bonding interface was observed between the LC Al-Cu coating and the matrix. In addition to the complete elimination of pores and microcracks, the microstructure of the LC composite coating became more refined, homogenized and densified due to dynamic recrystallization when it was subjected to FSP, especially FSP with pin. The sound bonding interface was not affected by FSP. The Al-Cu/AZ31 composite fabricated by LC and FSP hybrid method exhibited optimum corrosion performance. The maximum self-corrosion potential and self-corrosion current reached −0.907 V and 3.80 × 10−5 A, respectively, and 58.0% and 24.5% of the matrix, respectively. The corrosion damage behavior was dominated by pitting corrosion. [ABSTRACT FROM AUTHOR]

To describe the influence of design parameters on energy consumption, a structured information description framework oriented to energy-saving design of machinery equipment is proposed, which is composed of two sub-models: the energy consumption description model, and the design – energy consumption information correlation model. Firstly, the energy consumption composition of running procedures is analysed and the energy balance equations based on the kinetic energy theorem are built. Furthermore, a structured energy consumption description model – energy breakthrough structure (EBS) – is proposed; EBS is composed of some interrelated energy factors, and the energy factors are divided into two types: the energy element (EE) and the energy control unit (EC), where EE is the basic energy consumption description unit, and EC is the upper lower of energy factor, which is determined by the lower-level EE and EC. The relationships among energy factors can be divided into three types: Or, And, Proportional And; the energy relationships could be determined based on working conditions, design proposals or product structures. Additionally, based on the bond graph theory, the extracting method of energy features (such as force, displacement, pressure and flow) is brought forward, and a model related to the design parameters and energy was built. Finally, the feasibility of these models and methods was illustrated by taking the horizontal machining centre feed system as an example. [ABSTRACT FROM AUTHOR]

In this paper, we study rigid formation control systems modelled by double integrators. Two kinds of double-integrator formation systems are considered, namely formation stabilisation systems and flocking control systems. Novel observations on the measurement requirement, the null space and eigenvalues of the system Jacobian matrix will be provided, which reveal important properties of system dynamics and the associated convergence results. We also establish some new links between single-integrator formation systems and double-integrator formation systems via a parameterised Hamiltonian system, which, in addition, provide novel stability criteria for different equilibria in double-integrator formation systems by using available results in single-integrator formation systems. [ABSTRACT FROM AUTHOR]

In this study, we first sequenced and described the complete mitochondrial genome and phylogeny of Dicrurus hottentottus. The whole genome of D. hottentottus was 16,963 bp in length, and contained 13 protein-coding genes, 22 transfer RNA genes, 2 ribosome RNA genes, and 1 non-coding control regions. The overall base composition of the mitochondrial DNA was 32.56% for A, 25.56% for T, 27.72% for C, and 14.15% for G, with a GC content of 41.87%. A phylogenetic tree strongly supported that D. hottentottus (Dicruridae) is closely related to Corvidae and Laniidae with a high probability. [ABSTRACT FROM AUTHOR]

The Chinese kukri snake Oligodon chinensis belongs to family Colubridae and is distributed in southern China and North Vietnam. In this study, the total mitochondrial genome of O. chinensis was determined using next-generation sequencing. It is a circular molecule of 17,146 bp in length and contains 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and 2 control regions (CR1 and CR2), with a base composition of A 33.6%, G 12.2%, T 25.6%, and C 28.6%. Interestingly, a special 136 bp non-coding region, which was identified as the repeated sequence in CR1 and CR2. Oligodon chinensis lay a basal position within Colubrinae (Clade A). Ptyas mucosa was the nearest sister to Elaphe carinata and they were clustered in other species of Elaphe. The molecular data presented here would be useful for further study of O. chinensis. [ABSTRACT FROM AUTHOR]