Heavy metal ions retention by bi-functionalized lignin: Synthesis,applications, and adsorption mechanisms

Bi-functionalized lignin with amino and sulfonic groups (ASL) was synthesized via Mannich reaction and sulfomethylation. It was systematically characterized by FT-IR, element analysis, surface charge and XPS. Effects of initial pH, contact time and initial metal ion concentration on the adsorption of Cu(II) and Pb(II) onto ALS were studied. Results indicated that the biosorbent showed excellent performance for metals even from low pH solutions. The adsorption kinetics and isotherms could be described well with Pseudo-second-order and D–R model, respectively. Further investigation of the metal-loaded ASL by FT-IR and XPS elucidated the amino and sulfonic groups reacted with metals in different way.     

Copper brazing response of some advanced high strength steel grades

Sheet steels are commonly used in automotive powertrain applications wherein formed and assembled components undergo a copper brazing operation as part of the manufacturing process. For high performance applications including transmission pump housings and turbines, specially processed microalloyed steels have been developed and specified in order to develop the desired mechanical properties after exposure to brazing temperatures of ～1100 °C. New families of advanced high strength steel (AHSS) sheet are currently being developed and implemented. These are typified by increased alloy levels and exhibit unique property combinations that are particularly suited to auto body applications requiring the dual characteristics of high formability and high strength. Here it is considered that such grades may also be suited to powertrain components requiring high initial formability coupled with high final strength after copper brazing. That is, transformation strengthening during cooling after brazing is envisioned as a potential strengthening mechanism available with these new steels. In this work, initial screening results are reported to elucidate the response of some experimental AHSS to a simulated copper brazing operation during which the steels are taken into the austenitic temperature range and subsequently cooled at moderate rates to ambient conditions.     

Fatigue crack growth and fracture behavior of as-cast Ti-43.5Al-4Nb-1Mo-0.1B (TNM) compared to Ti-48Al-2Nb-2Cr (4822)

The effects of sample orientation and load ratio on the room-temperature fatigue crack growth and fracture behavior of a third-generation gamma titanium aluminide Ti-43.5Al-4Nb-1Mo-0.1B (TNM) were determined and compared with that of a second-generation alloy Ti-48Al-2Nb-2Cr (4822). Both materials are currently used as low pressure turbine blades in fuel-efficient gas turbine engines. Bend bar specimens, excised from the as-cast articles in the longitudinal and transverse directions to the casting direction, were tested at room temperature in lab air. Load ratios in the range 0.1–0.9 were used in fatigue testing to determine their effects on the fatigue threshold, Paris law slope, and stress intensity at overload in fatigue. Microscopy and fractography were used to document the effects of sample orientation on the fatigue crack path and morphology. Significant effects of changes in load ratio were observed on the fatigue threshold and Paris law slope, while effects of sample orientation were minimal for both alloys. The effects of microstructure length scale and differences in micro-constituents are discussed in relation to the properties measured.     

Nano-ruthenium particles supported on a core-shell shuttle: As an efficient lipophilic catalyst for the aerobic oxidation of biomass-derived 5-(Hydroxymethyl)furfural

We synthesize a novel mesoporous core-shell shuttle, which is lipophilic. It was used as the precursor loading the ruthenium nanoparticles to afford the catalyst for the aerobic oxidation of 5-(Hydroxymethyl)furfural. The whole oxidation process with the catalyst is highly efficient and chemo-selective. The shuttle can take Ru nanoparticles (RuNP) to the organic phase for catalyzing and make the reaction homogeneous resulting in a high conversion of 5-(Hydroxymethyl)furfural. The catalyst is stable and can be reused for at least five runs.     

Evaluation of biogenic amines in wine: Determination by an improved HPLC-PDA method

An improved, simple and sensitive method to quantify the biogenic amines ethanolamine, methylamine, ethylamine, isoamylamine and the usually investigated β-phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine, spermine has been developed and validated in red and white wines. The analytes were derivatised with dansyl chloride and separated by HPLC coupled with PDA detector. The calibration curves showed good linearity (r > 0.9990) and biogenic amines recovery varied from 72 to 97%. The repeatability ranged from 1 to 8% for red wine and from 1 to 5% for white wine. The detection and quantification limits were from 0.02 to 0.10 mg/L and from 0.08 to 0.30 mg/L, respectively. The method was successfully applied to detect and quantify biogenic amines in Italian red and white wines from Abruzzo Region. The proposed method is suitable for simultaneous detection and for accurate and precise quantification of eleven biogenic amines in wines.     

Acoustic emission in bearing steel during isothermal formation of midrib

The first attempt of an acoustic emission (AE) application for the control of isothermal transformation, at the temperature near the martensite start (M _S ) in 100CrMnSi6-4 bearing steel, is made herein. A unique method for recording the signals of the AE was developed. The Short Time Fourier Transform algorithm was used for displaying the signal values on the spectrogram graphs. Acoustic emission showed the nucleation and growth of the isothermal martensite in the residual austenite. The maximum power spectral density of signals was determined using the relative intensity of the RMS values. The observed energy of separated signals during the second stage of residual austenite decomposition is comparable to the energy of the initial stage at lower temperatures. It was proposed as a new process concept under paraequilibrium that involves the midrib formation and swing back in the kinetics of lower bainite.     

Aerated whey protein gels as a controlled release system of creatine investigated in an artificial stomach

A controlled creatine-release system has been developed from whey protein-based gels. Their functionalization was carried out by aeration and sodium ions induced “cold gelation” processes. The effect of protein concentration in the aerated whey protein gels at pH 7.0 and 8.0 was analyzed. Physicochemical properties of the aerated gels were evaluated. It was possible to obtain the ions induced whey protein aerated gel with well distributed creatine and different microstructure as well as rheological properties. Different protein concentrations and pH enabled obtaining gels with different rheological properties, texture, air fraction, diameter of air bubbles, microstructure and surface roughness. An increase in the protein concentration enhanced the hardness of the samples, regardless of their pH. The mechanical strength of gels prepared at pH 8 were higher than those obtained at pH 7, as was manifested by the smaller storage modulus of the latter. The former gel exhibited a microstructure between particulate and fine-stranded. A stronger gel matrix produced smaller air bubbles. Aerated gels produced at pH 7.0 had higher roughness than those obtained at pH 8.0. Optimal conditions for inclusion of air bubbles into the gel matrix were: 9% protein concentration at pH 8.0 and this aerated gel was selected for digestion in the artificial stomach. There is a small conversion of creatine to creatinine in the artificial stomach digestion process (9.6% after 6 h). The diffusion of creatine crystals from the aerated gel matrix was the mechanism responsible for the release process. Aerated whey protein gels can be used as matrices for time extended releasing of creatine in the stomach.     

A potential biogenetic membrane constructed by hydrophilic carbonized rice husk for sustaining electricity generation from hydrovoltaic conversion

In recent years, the research on hydrovoltaic conversion has made rapid progress, showing potential prospect in the field of power generation. However, it still faces many issues, such as expensive, uncontrollable engineering, undetermined mechanism and difficulty in commercialization. To provide a low-cost, undemanding and practical strategy, the carbonized rice husk was first used to construct a biogenetic membrane device in this work, giving a sustaining hydrovoltaic voltage at ∼160 mV. Relevant studies that associated with mechanism and key factors for hydrovoltaic process were also implemented founded on different test conditions. It is proved that the fluids flow driven by evaporation and capillary effect is an essential prerequisite for hydrovoltaic conversion. The mechanism for generating electricity should be attributed to the streaming potential theory, which can provide an electric potential difference by selective transmission of ions owing to the Debye shielding effect. Based on this as-proposed theory, the controlling projects like improving pressure difference (ΔP) of fluid, ambient temperature and humidity, which generally enhance the hydrodynamic driving force and effective flowing area, logically demonstrate positive answers on hydrovoltaic performance. Moreover, in view of the super hydrophilicity of carbonized rice husk, this biogenetic membrane has demonstrated strong sensitivity on human breath monitoring with rapid response for every breath, which provides a potential way for the practical application of hydrovoltaic effect.