•Mode-locked erbium-doped fiber laser with MAX phase Ti3AlC2 as saturable absorber.•The MAX phase embedded in PVA exhibits a saturable absorption of 2%.•The mode-locked captured owns an ultrashort ...pulse of 3.68 ps at 1557.77 nm.•The maximum peak power was 2.2 kW at the pump power of 131 mW.
We presented an ultrashort pulse generation in an erbium-doped fiber laser cavity using MAX-PVA as a mode-locker. A thin film of SA was prepared by mixing PVA with Ti3AlC2 as a saturable absorber inside the laser cavity. The optical nonlinearity was also demonstrated, revealing a saturable absorption of 2%, a non-saturable absorption of 58.2%, and a saturation intensity of 1.63 MW/cm2. The excellencies of MAX-PVA was proven as it initiates ultrafast laser with a duration of 3.68 ps corresponds to a repetition rate of 1.887 MHz. The ease of preparation, together with its superior optical, physical, thermal, and mechanical properties, makes it a favorable SA for pulse generation in an all-fiberized laser cavity.
Microalgae technology, if managed properly, has promising roles in solving food-water-energy nexus. The Achilles' heel is, however, to lower the costs associated with cultivation and harvesting. As a ...favorable technique, application of membrane process is strongly limited by membrane fouling. This study evaluates performance of nylon 6,6 nanofiber membrane (NFM) to a conventional polyvinylidene fluoride phase inverted membrane (PVDF PIM) for filtration of Chlorella vulgaris. Results show that nylon 6,6 NFM is superhydrophilic, has higher size of pore opening (0.22 vs 0.18 μm) and higher surface pore density (23 vs 18 pores/μm2) leading to higher permeance (1018 vs 493 L/m2hbar) and better fouling resistant. Such advantages help to outperform the filterability of PVDF PIM by showing much higher steady-state permeance (286 vs 120 L/m2hbar), with comparable biomass retention. In addition, unlike for PVDF PIM, imposing longer relaxation cycles further enhances the performance of the NFM (i.e., 178 L/m2hbar for 0.5 min and 236 L/m2hbar for 5 min). Overall findings confirm the advantages of nylon 6,6 NFM over the PVDF PIM. Such advantages can help to reduce required membrane area and specific aeration demand by enabling higher flux and lowering aeration rate. Nevertheless, developments of nylon 6,6 NFM material with respect to its intrinsic properties, mechanical strength and operational conditions of the panel can still be explored to enhance its competitiveness as a promising fouling resistant membrane material for microalgae filtration.
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•This study compares performance of nylon 6,6 NFM with PVDF PIM.•Nylon 6,6 nanofiber has structural and surface chemistry advantages.•Nylon 6,6 NFM has more than double in productivity over the PVDF PIM.•Nylon 6,6 has a great potential as a NFM for microalgae harvesting.
A review of advances in the use of lubrication techniques during machining operations as well as the application of state-of-the-art nanofluids in machining is presented in this research article. A ...brief review of the available literature on the environmental impact and the health hazards associated with metal working fluids is also included. The performance and drawbacks of different techniques are discussed in terms of machining parameters and output variables. The review of different lubrication techniques finally ends up in the favor of minimum quantity lubrication and cooling technique as a potential alternate to flooded and conventional cooling conditions in different machining processes in terms of dealing with the ecological, social and human health concerns and the finances coupled with the use of metal working fluids in machining processes.
► Dense CNT were grown on carbon fiber and glass fiber by use of floating catalyst CVD method. ► CNT showed different growing mechanism on carbon and glass fiber. ► Short fiber-CNT-composites showed ...enhanced mechanical properties. ► CNT coating enhanced fiber–matrix interaction and acted as additional reinforcement.
Dense carbon nanotubes (CNTs) were grown uniformly on the surface of carbon fibers and glass fibers to create hierarchical fibers by use of floating catalyst chemical vapor deposition. Morphologies of the CNTs were investigated using scanning electronic microscope (SEM) and transmission electron microscope (TEM). Larger diameter dimension and distinct growing mechanism of nanotubes on glass fiber were revealed. Short carbon and glass fiber reinforced polypropylene composites were fabricated using the hierarchical fibers and compared with composites made using neat fibers. Tensile, flexural and impact properties of the composites were measured, which showed evident enhancement in all mechanical properties compared to neat short fiber composites. SEM micrographs of composite fracture surface demonstrated improved adhesion between CNT-coated fiber and the matrix. The enhanced mechanical properties of short fiber composites was attributed to the synergistic effects of CNTs in improving fiber–matrix interfacial properties as well as the CNTs acting as supplemental reinforcement in short fiber-composites.
Ultra-High Temperature Materials (UHTMs) are at the base of entire aerospace industry; these high stable materials at temperatures exceeding 1600 °C are used to manage the heat shielding to protect ...vehicles and probes during the hypersonic flight through reentry trajectory against aerodynamic heating and reducing plasma surface interaction. Those materials are also recognized as Thermal Protection System Materials (TPSMs). The structural materials used during the high-temperature oxidizing environment are mainly limited to SiC, oxide ceramics, and composites. In addition to that, silicon-based ceramic has a maximum-use at 1700 °C approximately; as it is an active oxidation process over low temperature and water vapor environment condition. However, a great emphasis is required for developing structural materials in oxidation and rapid heating environment where the temperature is greater than 1700 °C. This review covers briefly all main types of Thermal Protection Systems (TPSs) and all the materials are used to fabricate them with the maximum operational temperatures. Also, it covers the promised UHTMs (SiC, ZrB2, HfB2, SiB6 and B4C) which are currently using for several aerospace applications, especially for TPS. Besides, it discusses the oxidation of SiC, B4C, SiB6, ZrB2 and HfB2. Therefore, the carbides and borides of the transition metals, Zr and Hf have a high-melting temperature and good stability in forming high-melting temperature oxides.
We have reported a simple chemical preparation method of gold nanorods (AuNR) incorporated reduced graphene oxide (rGO) nanocomposite. Thus, synthesized AuNR decorated rGO (AuNR@rGO) nanocomposite ...has directly coated on glassy carbon electrode (GCE) for the highly sensitive and selective electrochemical sensing of Dihydronicotinamide adenine dinucleotide (NADH). The electrocatalytic activity of AuNR@rGO/GCE-modified electrode towards the oxidation of NADH has elaborately discussed. From the analysis of results, the amperometric current is increased linearly while increasing the NADH concentration in the range of 1–31 μM and the small limit of detection (LoD) has estimated as 0.22 μM (S/N = 3). Furthermore, the interferent study of the AuNR@rGO/GCE-modified electrode confirms for the sensitivity and unique detection ability of the electrode when other competitive biomolecules like glucose, uric acid, ascorbic acid, and dopamine are present.
•A simple chemical preparation method of Au NR @rGO nanocomposite.•The cyclic voltammetric studies of the Au NR @rGO/GCE-modified electrode.•AuNR@rGO/GCE-modified electrode demonstrated enhanced electrocatalytic activity towards NADH detection.•AuNR@rGO which enabled the NADH to be detected by a simple amperometric sensor.
Sprouty proteins are involved in organogenesis, particularly during the branching of endothelial tubes, and existing evidence suggests that Sprouty's point of action lies downstream of receptor ...signaling to inhibit the activation of the central Ras/Erk pathway. How Sprouty proteins accomplish their inhibitory action and whether they interact with other signaling pathways are significant questions. Sprouty proteins are devoid of any recognizable protein interaction domain, and clues as to how they function have been mainly derived from screening for interacting partners. Conserved across all the Sprouty proteins are three sequences: a Cbl-tyrosine kinase-binding (TKB) binding motif centered on an obligatorily phosphorylated tyrosine (Y55 in Sprouty2), a serine-rich motif (SRM) and a cysteine-rich domain (CRD). With the exception of a handful of proteins that bind to the N-terminus, most of the binding to Sprouty occurs via the CRD, predominantly by serine/threonine kinases that target sites within the SRM on Sprouty. Some of the resultant increase in phosphorylation is opposed by activated protein phosphatase 2A that binds to the N-terminal Cbl-TKB binding motif. Significantly, two ubiquitin E3 ligases also bind to the N-terminus of Sprouty: c-Cbl binds with high affinity to the TKB binding motif and SIAH2 binds constitutively to a different site; both proteins are able to direct the ubiquitination of Sprouty proteins and its destruction. The collective evidence points to Sprouty proteins as being substantially covalently-modified to control its location, stability, association, and destruction. With such stringent control of the Sproutys, the main question is what key proteins does this facilitator bring together?
In machining, heat concentration is generated at the surface contact between the tool and workpiece. This is the effect of hard frictions at the shear cutting plane to remove hard and brittle ...materials. The highly adhesive behavior of aluminum alloy 6061-T6 is more severe in higher cutting temperature, which may affect tool failures such as flank wear, tool chip and built-up edge, particularly on the edge of cutting inserts during the process. As a result, this may lead to the rough surface and low-dimensional accuracy of the machined parts. Realizing that metal-cutting industry players are demanding high-quality products with better surface finish and dimensional accuracy led to this study. Aluminum alloy 6061-T6 is a standard alloy used in automotive, aerospace and food packaging due to good hardness, high strength-to-weight ratio, resistance to corrosion and weldability. In order to address this problem, a newly developed metal working fluid which is SiO
2
-Al
2
O
3
-ZrO
2
tri-hybrid nanofluid is applied in the cutting zone to achieve a good surface finish of the machined parts and lowering the cutting temperature. This study is the first attempt to enhance machining performance, particularly at high-speed machining, by employing a combination of tri-hybrid nanofluids and a minimum quantity lubricant technique. Industrial standards include uncoated tungsten carbide and CVD TiCN-Al
2
O
3
carbide used during machining of aluminum alloy 6061-T6. The minimum quantity lubricant method is an alternative in supplying the lubricant into the machining zone due to flood machining and conventional fluid possess safety, health, economic and environmental effects. In this study, the experimental data were analyzed statistically using analysis of variance and response surface methodology. The responses studied were reduced significantly when tri-hybrid nanoparticles present at the cutting interface with higher MQL flow rate and concentration. There are two-factor interactions which are significant to the responses studied. Therefore, the combinations of MQL and excellent tri-hybrid nanofluids characteristics have enhanced between 16 and 76% of surface roughness and the cutting temperature, respectively, which is very promising in the future.
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