Ethanol absorption from CO2 using solutions of glycerol and glycols

CO₂ stripping during fermentation is a possible way of increasing the production of ethanol in distilleries. Ethanol, water, and carbon dioxide are the main compounds in the exiting gas mixture. To date, few studies have proposed the use of absorption to recover ethanol from this mixture or have considered different absorbents for this purpose. This work evaluates different absorbent solutions used to recover ethanol vapor from CO₂ gas. Glycols and glycerol can provide easier separation of ethanol than water, with lower distillation energy demand. A statistical experimental design was used to compare the mass transfers of ethanol from the gas phase to the liquid phase, using solutions of glycerol, ethylene glycol, and diethylene glycol. High concentrations of these substances did not favor the absorption of ethanol. The best results were achieved with 25% absorbent solutions, which offered better options than water for the recovery of ethanol from CO₂ gas in absorption columns and could increase the productivity of first generation bioethanol production.     

A parametric investigation on seat/occupant contact forces and their relationship with initially perceived discomfort using a configurable seat

The present work investigates the contact forces between sitters and seat as well as their correlations with perceived discomfort. Twelve different economy class aeroplane seat configurations were simulated using a multi-adjustable experimental seat by varying seat pan and backrest angles, as well as seat pan compressed surface. Eighteen males and 18 females, selected by their body mass index and stature, tested these configurations for two sitting postures. Perceived discomfort was significantly affected by seat parameters and posture and correlated both with normal force distribution on the seat-pan surface and with normal forces at the lumbar and head supports. Lower discomfort ratings were obtained for more evenly distributed normal forces on the seat pan. Shear force at the seat pan surface was at its lowest when sitters were allowed to self-select their seat-pan angle, supporting that a shear force should be reduced but not zeroed to improve seating comfort.

Practitioner Summary: The effects of seat-pan and backrest angle, anthropometric dimensions and sitting posture on contact forces and perceived discomfort were investigated using a multi-adjustable experimental seat. In addition to preferred seat profile parameters, the present work provides quantitative guidelines on contact force requirement for improving seating comfort.     

Salmonella in eggs: From shopping to consumption—A review providing an evidence-based analysis of risk factors

Nontyphoidal salmonellae are among the most prevalent foodborne pathogens causing gastrointestinal infections worldwide. A high number of cases and outbreaks of salmonellosis are associated with the consumption of eggs and egg products, and several of these occur at the household level. The aim of the current study is to critically evaluate the current status of knowledge on Salmonella in eggs from a consumer's perspective, analyzing the hazard occurrence and the good practices that should be applied to reduce salmonellosis risk. Following a HACCP (Hazard Analysis and Critical Control Point) based approach, some steps along the food journey were identified as Critical Consumer Handling (CCH)—steps in which consumers, through their behavior or choice, can significantly reduce the level of Salmonella in eggs and egg products. From shopping/collecting to consumption, each of these steps is discussed in this review to provide an evidence-based overview of risk factors of human salmonellosis related to egg consumption. The main message to consumers is to choose Salmonella-free eggs (those that some official entity or producer guarantees that does not contain Salmonella), when available, especially for dishes that are not fully heat treated. Second, as guaranteed Salmonella-free eggs are only available in a few countries, refrigerated storage from the point of collection and proper cooking will significantly reduce the risk of salmonellosis. This will require a revision of the actual recommendations/regulations, as not all ensure that eggs are maintained at temperatures that prevent growth of Salmonella from collection until the time of purchasing.     

Antibiofilm activity of the essential oil of citronella (Cymbopogon nardus) and its major component,geraniol, on the bacterial biofilms of Staphylococcus aureus

Food Science and Biotechnology - Medicinal plants with antimicrobial action have been investigated for uses against biofilms, among which, Cymbopogon nardus, citronella, stands out as a promising...     

A Comparison Between Kinetic Test Results and Natural Weathering: The Abandoned Kettara Mine Tailings Pond

More than three million tons of sulfide tailings were discarded without any protection for more than 36 years at the since-abandoned Kettara mine. The impact of these tailings as well as the coarse wastes disorderly dumped on the surface site is highlighted by the elevated sulfate levels in the wells downstream of the wastes. Kinetic tests carried out on these sulfide tailings over 10 years ago, showed similar trends in metal dissolution despite large difference in test duration (21 and 53 weeks for the weathering and humidity cell tests, respectively). 40% of the sulfate release occurred in the first 3 weeks of the humidity test. However, in this study, the elevated sulfate levels in the groundwater was shown not be linked to the tailings, where the original sulfide material is still present under an oxidized layer of 10 cm–1.2 m. Thus, kinetic test results should not be extrapolated to field scale without accounting for site-specific factors, especially particle size and climate.     

In vivo assessment of the corrosion of nickel–titanium orthodontic archwires by using scanning electron microscopy and atomic force microscopy

This study was undertaken to assess in vivo the corrosion in two commercial nickel–titanium (NiTi) orthodontic archwires removed from the oral cavity of patients using fluoride mouthwashes. Five volunteers took part in this study on the corrosion behavior of two brands of NiTi archwires (3M and AO (brand of archwire)) during use of two mouthwashes with neutral sodium fluoride 1.1%, one with acidulated fluoride 1.1%, and one with placebo and a control group. Each patient used one mouthwash in three different periods of time for 1 min a day for 30 days. The archwires were assessed with scanning electron microscopy and atomic force microscopy for qualitative and quantitative analysis. The values obtained with atomic force microscopy (AFM) were submitted to normality test, two‐way analysis of variance, and Tukey's test at a significance level of 5%. The AFM images showed a gradual qualitative increase in the roughness of both types of wire between the treatments: control < placebo < neutral fluoride < acidulated fluoride. The arithmetic average of the roughness and root mean square of the roughness were similar. As for 3M archwires, only the acidulated fluoride group differed statistically from the others. As for AO archwires, the control and placebo groups did not differ from each other, but differed from the other fluoride treatments. The group using neutral fluoride also differed significantly from the acidulated fluoride group. 3M archwires were not affected by daily oral challenges. AO archwires were not affected by daily oral challenges either; their association with fluoride, either neutral or acidulated, increased their roughness.