Kenaf Bast Fibers—Part I: Hermetical Alkali Digestion

The objective of this study was to develop a hermetical alkali digestion process to obtain single cellulosic fibers from kenaf bast. Kenaf bast were hermetically digested into single fiber using a 5% sodium hydroxide solution for one hour at four different temperatures (80°C, 110°C, 130°C, and 160°C). The hermetical digestion process used in this study produced fibers with high cellulose content (84.2–92.3%) due to the removal of lignin and hemicelluloses. The surface hardness and elastic modulus of the fibers digested at 130°C and 160°C were improved significantly compared with those digested at 80°C. The tensile modulus and tensile strength of the individual fibers reduced as the digestion temperature increased from 110°C to 160°C. Micropores were generated in fiber cell wall when the fibers were digested at 130°C and 160°C. The studies on the composites that were made from polypropylene reinforced with the digested fibers indicated that the compatibility between the digested fibers and polypropylene matrix was poor

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Oxygen-peroxide (Eop) Delignification and Peroxide (P) Bleaching of Bagasse Kraft Pulp

699-706An EopQP sequence is used to delignify and bleach a bagasse kraft pulp. In the Eop step, a reduction of the kappa number by 60 per cent and improvement in the brightness by 16.5 units were achieved. The Q step reduces the content of Mn, Fe and Cu ions by 48-60 per cent. A bleaching system consisting of 4 per cent H2O2, 2.5 per cent NaOH, 0.3 per cent MgSO4, and 0.05 per cent DTPMPA could bleach the EopQ treated pulp to 80 per cent ISO brightness, 2.6 kappa number and ~700 mL/g viscosity. The brightness is increased to 82 per cent at reasonable viscosity values (> 650 mL/g) by adding 0.05 per cent 1, 10-phenanthroline to a bleaching system containing lower peroxide concentration (3 per cent) and higher DTPMPA charge (0.1 per cent)

Pulping of <i>Casuarina glauca </i>with ASAM - An Environmental Friendly Process

799-806ASAM pulping process has been experimented on Casuarina glauca. The pulping parameters such as methanol concentration, cooking time, chemical charge, and alkali ratio, affecting the chemical and physical properties of the pulp are determined .. For ASAM I cooks, NaOH is the supporting alkali, while in ASAM II pulping, Na2CO3 is the supporting alkali. The best ASAM I pulping is achieved at 22.5 and 25 per cent chemical charge with 0.7 and 0.8 alkali ratio while the best ASAM II pulping is achieved at 27.5 per cent chemical charge and 0.6 alkali ratio. When both the pure alkalies were used, some changes in the pulp properties were observed by varying the ratio of NaOH: Na2CO3. Pulp- and papermaking properties of Casuarina cooked by the ASAM process are observed to be superior to Casuarina pulp obtained by the kraft process

Amino-Functionalized Cellulose Nanofiber/Lignosulfonate New Aerogel Adsorbent for the Removal of Dyes and Heavy Metals from Wastewater

Due to the increasingly widespread water pollutants and the high cost of treatment methods, there is a demand for new, inexpensive, renewable, and biodegradable adsorbent materials for the purification of wastewater contaminants. In this study, a new biocomposite aerogel (Amf-CNF/LS) was prepared using a chemically cross-linking method between the amino-functionalized cellulose nanofibers (Amf-CNF) and lignosulfonates (LS). The physical and chemical properties of the prepared aerogel were investigated using several techniques including elemental analysis, scanning electron microscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), and N2 adsorption-desorption analysis. The Amf-CNF/LS aerogel was then applied for the removal of methylene blue (MB), rhodamine B dye (RhB), and the heavy metal cadmium ion (Cd2+) from synthetic wastewater solutions. The adsorption parameters controlling the adsorption process including the pH, contact time, adsorbent dosage, and adsorbate concen-tration were optimized. High adsorption kinetics and isotherms were observed, with the adsorption isotherms of the Amf-CNF/LS aerogel fitting the Langmuir model with maximum adsorption capacities of 170.94, 147.28, and 129.87 mg/g for MB, RhB, and Cd2+, respectively. These results show that Amf-CNF/LS aerogel is a promising green and inexpensive adsorbent for MB, RhB, and Cd2+ removal from wastewater