A novel application of cellulose aerogel composites from pineapple leaf fibers and cotton waste: Removal of dyes and oil in wastewater

Journal of Porous Materials - In a world where demands for freshwater are ever-growing, wastewater remediation becomes a global concern. Especially, water, which is contaminated by oil, dyes, poses...     

Crystal growth inhibition of tetrahydrofuran hydrate with poly(N-vinyl piperidone) and other poly(N-vinyl lactam) homopolymers

Poly(N-vinyl pyrrolidone) (PVP) containing the 5-ring lactam and poly(N-vinyl caprolactam) (PVCap) containing the 7-ring lactam are well-known kinetic hydrate inhibitors (KHIs). For the first time we have synthesised and studied the performance of poly(N-vinyl piperidone) (PVPip), containing the 6-ring lactam, as a kinetic hydrate inhibitor. In the first part of the study we have investigated the ability of PVPip to inhibit the growth of tetrahydrofuran SII hydrate crystals. The results are compared to those of PVP and PVCap. Various polymer molecular weights have been investigated at varying subcoolings. PVPip shows an intermediate growth inhibition performance compared to PVP and PVCap at similar polymer molecular weights. In addition, the weight percentage concentration of polymer needed to achieve complete THF hydrate crystal growth inhibition increases as the polymer molecular weight decreases.     

Drastic enhancement of mechanical properties of Ca3Co4O9 by B4C addition

Ca₃Co₄O₉ with B₄C additions in different proportions (0, 0.10, 0.25, 0.5, and 0.75 wt.%) have been fabricated using the classical solid-state method. Powder XRD patterns have displayed that Ca₃Co₄O₉ phase is the major one in all samples. Microstructural observations showed that B₄C has been superficially oxidized, producing liquid B₂O₃ during sintering, and reacting with the Ca₃Co₄O₉ grains to produce bridges between them. In spite of the increase of porosity, these bridges led to an important raise (more than two times) of mechanical properties when compared to the pristine materials. On the other hand, while B₄C addition has not influenced S values, it has decreased electrical resistivity, thermal conductivity, and thermal expansion. Consequently, ZT values have been also increased, reaching 0.24 at 800 °C in 0.25 wt.% B₄C containing samples, which is very close to the best values reported in the literature, and two times higher than the obtained in pure materials in this work.     

Flexible Pressure Sensors for Objective Assessment of Motor Disorders

Monitoring body motion is relevant to motor control disorders as well as assessment of fine motor skills in child development. Furthermore, motion tracking is necessary for rehabilitation monitoring and injury prevention and benefits both sick and healthy individuals. Flexible pressure sensors based on resistors, capacitors, inductors, or transistors are reviewed in the context of healthcare measurements, ranging from physiological signals to body movement characteristics such as grip and gait. To demonstrate the use of flexible pressure sensors for motor assessment, a touch sensing glove that evaluates fine motor skills in autism research is developed. The results show that autistic children perform fewer taps per minute compared to typically developing children, with larger variations in tap durations. In a second example, a force and motion sensing glove is developed to assess spasticity, a neuromuscular disorder that causes muscle stiffness/resistance and jerky movement. Analyses of force versus velocity show movement‐dependent muscle resistance in a patient with spasticity. Through these flexible sensor systems, the shift from subjective scores to objective measurement will promote better diagnosis and dramatically improve the accuracy in tracking patient response to therapy.     

Elucidating the Detectivity Limits in Shortwave Infrared Organic Photodiodes

While only few organic photodiodes have photoresponse past 1 µm, novel shortwave infrared (SWIR) polymers are emerging, and a better understanding of the limiting factors in narrow bandgap devices is critically needed to predict and advance performance. Based on state‐of‐the‐art SWIR bulk heterojunction photodiodes, this work demonstrates a model that accounts for the increasing electric‐field dependence of photocurrent in narrow bandgap materials. This physical model offers an expedient method to pinpoint the origins of efficiency losses, by decoupling the exciton dissociation efficiency and charge collection efficiency in photocurrent–voltage measurements. These results from transient photoconductivity measurements indicate that the main loss is due to poor exciton dissociation, particularly significant in photodiodes with low‐energy charge‐transfer states. Direct measurements of the noise components are analyzed to caution against using assumptions that could lead to an overestimation of detectivity. The devices show a peak detectivity of 5 × 10¹⁰ Jones with a spectral range up to 1.55 µm. The photodiodes are demonstrated to quantify the ethanol–water content in a mixture within 1% accuracy, conveying the potential of organics to enable economical, scalable detectors for SWIR spectroscopy.     

Application of quantitative 19F and 1H NMR for reaction monitoring and in situ yield determinations for an early stage pharmaceutical candidate

Quantitative NMR spectrometry (qNMR) is an attractive, viable alternative to traditional chromatographic techniques. It is a fast, easy, accurate, and nondestructive technique which allows an analyst to gain quantitative information about a component mixture without the necessity of authentic reference materials, as is the case with most other analytical techniques. This is ideal for the synthesis of active pharmaceutical ingredients (API) that are in the early stages of development where authentic standards of the analytes may not be available. In this paper, the application of (19)F and (1)H qNMR for reaction monitoring and in situ potency determinations will be discussed for an early stage pharmaceutical candidate with several analytical challenges. These challenges include low UV absorption, low ionization, thermal instability, and lack of authentic reference standards. Quantitative NMR provided quick, fit-for-purpose solutions for process development where conventional separation techniques were limited.