Surface improvement on water and oil affinities and absorption rate of PVA/Tung oil-coated paperboard and fiberboard

A novel coating material on paperboard and fiberboard from poly(vinyl alcohol) (PVA) modified with Tung oil was developed. The PVA/Tung oil coating was cured at several conditions: 25, 40, 50, and 60°C, in the presence of two types of catalysts, i.e., thermal catalyst using potassium persulfate (KPS) and redox catalyst using KPS and sodium thiosulfate. The chemical crosslinked structure of PVA/Tung oil-coating films was confirmed by FTIR. The result indicated the decrease in the double bonds of Tung oil by crosslinking reaction, especially at 60°C. In comparison with the same curing temperature, the films with redox catalyst showed more reduction in the number of double bonds of Tung oil. DMA results of the PVA/Tung oil-coating materials with redox catalyst showed the lowering of the heights of both β transition peak of Tung oil and α transition peak of PVA. FTIR and DMA results confirmed the more efficient crosslinking reaction of redox catalytic system than that of the thermal catalytic system. The water resistance and mechanical properties of these coating materials exhibited better values as projected to higher curing temperature and redox catalyst. SEM images showed the smooth surface of PVA/Tung oil covered on the paperboards with ~72 µm in thickness. The contact angle of water or oil drop and dynamic change in contact angle on the surfaces of PVA/Tung oil-coated paperboards and fiberboards were investigated. The results show the contact angles for both water and oil were lower than those of the uncoated ones, indicating the improvement of water and oil affinities of the PVA/Tung oil-coating materials. The dynamic changes in contact angle of the coated ones also decreased, suggesting the reduction in water and oil absorption rates of these coated substrates.     

Simulation and thermodynamic analysis of chemical looping reforming and CO2 enhanced chemical looping reforming

The production of hydrogen from methane via two chemical looping reforming (CLR) processes was simulated and thermodynamically analysed, one process being the conventional CLR process, the other being a CO₂ sorption enhanced process. The aim of the work was to identify suitable operating conditions for obtaining an optimum hydrogen gas purity and yield, whilst operating auto-thermally, at atmospheric pressure and with no carbon formation. In both simulations, the reactors were simulated using the Gibbs minimisation technique. NiO was used as the oxygen storing species, whilst CaO was used as the CO₂ adsorbent.     

Detailed microkinetic modelling of syngas to hydrocarbons via Fischer Tropsch synthesis over cobalt catalyst

Fuels production from syngas via Fischer Tropsch synthesis (FTs) is an alternative technology for clean energy production. The microkinetic model is a promising approach for gaining insight into FTs activity. In this study, a systematic microkinetic model was proposed to develop a process for cobalt-catalyzed FTs. All possible elementary reactions based on the carbide mechanism and characteristics of catalyst sites were considered in the kinetic model. The effects of the reaction rate constant, reaction pathways, and H₂ to CO ratio were represented by a kinetic parameter, reaction path, and operating parameter, respectively. The model could accurately predict product distribution trends, with an R² value and mean absolute relative residuals percentage of 0.91–0.93 and 5–43%, respectively, in comparison with experimental data. Hydrogen utilization was predicted and analyzed. High model accuracy was achieved, with a 10^?10–10^?3% error in the material balance.     

Magnetic composite sponges based on chitosan and whey protein modified magnetite nanoparticles for dye removal from water

Journal of Porous Materials - In this work, a novel application of whey protein isolate (WPI) for surface coating of magnetic nanoparticles (MNPs) is demonstrated. WPI-modified MNPs (WPI-MNPs) were...     

Vibration effect on hardness measurement

In this paper, the effect of ground vibration on hardness measurement, Rockwell scale C hardness, Vickers scale HV1 hardness and Leeb hardness is studied. The hardness machines were placed on the vibration table. The vibration signal is single frequency sinusoidal wave, which frequency and amplitude of vibration can be controlled. The hardness value at free from vibration state is used as a reference to calculate the error of each hardness measurement at certain frequency and amplitude. Two Rockwell hardness testing machines are used to measure hardness blocks: 20, 40, and 60 HRC. Both machines give the same tendency. Significant negative errors occur around frequency 5–15 Hz. Moreover, ground vibration has more impact on the soft range of hardness than hard range. The result from this paper can be used as guideline for laboratory to control environmental vibration amplitude to be less than 0.01 m/s² for frequency (10 ± 5) Hz and 0.05 m/s² for other in Rockwell scale C hardness measurement. Effect of vibration on Vickers and Leeb hardness measurement is preliminarily studied. Results on 200 HV1 and 900 HV1 measurement show that vibration creates peak of error at frequency 20 Hz of amplitude more than 0.01 m/s² and the effect can be observable at all frequency for amplitude of 0.04 m/s². Different from Rockwell and Vickers, Leeb hardness measurement is not influenced by vibration in this experiment.     

Comparative composition,diversity, and abundance of oligosaccharides in early lactation milk from commercial dairy and beef cows

Prebiotics are nondigestible dietary ingredients, usually oligosaccharides (OS), that provide a health benefit to the host by directly modulating the gut microbiota. Although there is some information describing OS content in dairy-source milk, no information is available to describe the OS content of beef-source milk. Given the different trait emphasis between dairy and beef for milk production and calf survivability, it is plausible that OS composition, diversity, and abundance differ between production types. The goal of this study was to compare OS in milk from commercial dairy and beef cows in early lactation. Early-lactation multiparous cows (5–12 d in milk) from 5 commercial Holstein dairy herds and 5 Angus or Angus hybrid beef herds were sampled once. Milk was obtained from each enrolled cow and frozen on the farm. Subsequently, each milk sample was assessed for total solids, pH, and OS content and relative abundance. Oligosaccharide diversity and abundance within and between samples was transformed through principal component analysis to reduce data complexity. Factors from principal component analysis were used to create similarity clusters, which were subsequently used in a multivariate logistic regression. In total, 30 OS were identified in early-lactation cow milk, including 21 distinct OS and 9 isomers with unique retention times. The majority of OS detected in the milk samples were present in all individual samples regardless of production type. Two clusters described distribution patterns of OS for the study sample; when median OS abundance was compared between the 2 clusters, we found that overall OS relative abundance was consistently greater in the cluster dominated by beef cows. For several of the structures, including those with known prebiotic effect, the difference in abundance was 2- to 4-fold greater in the beef-dominated cluster. Assuming that beef OS content in milk is the gold standard for cattle, it is likely that preweaning dairy calves are deprived of dietary-source OS. Although supplementing rations with OS is an approach to rectify this deficiency, understanding the health and productivity effects of improving OS abundance being fed to preweaning calves is a necessary next step before recommending supplementation. These studies should account for the observation that OS products are variable for both OS diversity and structural complexity, and some products may not be suitable as prebiotics.