Mechanical properties of continuous bamboo fiber-reinforced biobased polyamide 11 composites

This study is devoted to the analysis of the properties of continuous bamboo fiber (BF)-reinforced polyamide 11 (PA 11) composites. The SEM observations highlighted continuity between BFs and the polymeric matrix showing a high density of hydrogen bonds. The comparative calorimetric study of the matrix and its composites showed that the crystallinity of PA 11 was not modified by the presence of bamboo fibers. The physical aging observed in PA 11 is no more observed in composites due to physical interactions between PA 11 and BFs. The mechanical properties were investigated by tensile strength and dynamic mechanical analysis. The introduction of BFs enhanced Young's modulus of the matrix by a factor of 10. The presence of BFs also improved the storage shear modulus G′ over the whole temperature range. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47623.     

Coupling heat storage to nuclear reactors for variable electricity output with baseload reactor operation

Nuclear reactors produce heat and thus can couple to heat storage systems to provide dispacthable electricity while the reactor operates at full power. Six classes of heat storage technologies couple to light-water reactors with steam cycles. Firebrick Resistance-Heated Energy Storage (FIRES) converts low-price electricity into high-temperature stored heat for industry or power. FIRES and brick recuperators coupled to nuclear brayton power cycles may enable high-temperature reactors to buy electricity when prices are low and sell electricity at higher price.     

Poly(N-isopropylacrylamide)/mesoporous silica thermosensitive composite hydrogels for drug loading and release

Temperature-sensitive hydrogels are attracting increasing attention for controlled drug delivery. However, achieving high drug loadings and sustained drug release remains challenging. Herein, we describe the successful synthesis of a series of novel temperature-sensitive poly(N-isopropylacrylamide) (PNIPA)/mesoporous silica nanoparticles (MSN) hydrogels by physical crosslinking of NIPA with MSN. The external and internal structures, temperature sensitivity, drug-loading capacity, and blood compatibility of the PNIPA/MSN composite hydrogels are studied. Results show that MSN addition improved the network structure and adjusted the size of the hole, MSN could also act as drug carrier, thereby enhancing the drug loading capacity. The composite hydrogels underwent a phase transition at 33.7 °C (at the lower critical solution temperature). The hemolysis rate of the composite hydrogels was less than 1%, thus they can be classified as a nonhemolytic materials with good biocompatibility. The composite hydrogels reported here thus have great potential in drug transport and temperature-activated drug release. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48391.     

Risks of modular integrated construction: A review and future research directions

Stakeholders remain skeptical in adopting modular integrated construction (MiC) because of the associated risks and uncertainties, although its benefits have been extensively documented. The unique business model of MiC nurtures several risks and uncertainties different from those of the conventional construction approach. Despite the growing attention on MiC with its market expansion, no systematic evaluation is in place to monitor its risks research progress. Accordingly, this research reviewed published literature addressing the risks associated with MiC from 1992 to 2019. Analysis reveals that the research publications on risks of MiC witnessed a steady growth, with considerable progress occurring in the last decade. Result implies that the risk of MiC has gained extra attention in the construction engineering and management domain in recent times. Existing empirical studies have focused heavily on perceived implementation risks, supply chain risks, schedule risks, investment risks, structural risks, ergonomic risks, and MiC risk management strategies, which indicate that MiC is associated with a host of risk events. The research further identified the critical risk events (CREs) in the application of MiC based on frequency of occurrence. The identified CREs contributes to the checklists of risk events in the implementation of offsite construction (OSC). The latter may be useful in risk planning, especially where the MiC is less developed, and fewer or no bespoke risk assessment exists. Research gaps in existing studies are highlighted in this research, and areas for further studies are then proposed. Thus, it makes a useful contribution to the scholarly literature on the risk of OSC and may prove useful to offsite construction researchers, industry practitioners, and project managers.     

Sulfolane biodegradation potential in aquifer sediments at sour natural gas plant sites

Sulfolane is used in the treatment of sour natural gas. It is a highly water soluble compound that has been introduced into soils and groundwaters at a number of sour gas processing plant sites. Aquifer sediments from contaminated locations at three sites in western Canada were assessed for microbial activity and their ability to degrade sulfolane under aerobic and five anaerobic (nitrate-, Mn(IV)-, Fe(III)-, sulfate- and CO₂-reducing) conditions. The microcosms were supplemented with 200 mg/L sulfolane and adequate supplies of N, P, and the appropriate terminal electron acceptor. Microcosms containing contaminated aquifer sediments from each of the three sites were able to degrade sulfolane aerobically at 8°C and 28°C, and the biodegradation followed zero-order kinetics. The lag times before the onset of sulfolane biodegradation were shorter when sulfolane-contaminated sediments were used as inocula than when uncontaminated soils were used. No anaerobic sulfolane biodegradation was observed at 28°C, nor was sulfolane biodegradation observed at 8°C under Fe(III)-, sulfate- and CO₂-reducing conditions. At 8°C, anaerobic degradation of sulfolane coupled to Mn(IV) reduction was observed in microcosms from two sites, and degradation coupled to nitrate reduction was seen in a microcosm from one of the contaminated sites.     

The choice of an input-output table embedded in regional econometric input-output models

In this paper, we investigate the role of input-output data sources in regional econometric input-output models. While there has been a great deal of experimentation focused on the accuracy of alternative methods for estimating regional inputoutput coefficients, little attention has been directed to the role of accuracy when the input-output system is nested within a broader accounting framework. The issues of accuracy were considered in two contexts, forecasting and impact analysis focusing on a model developed for the Chicago region. We experimented with three input-output data sources: observed regional data, national input-output, and randomly generated inputoutput coefficients. The effects of different sources of input-output data on regional econometric input-output models revealed that there are significant differences in results obtained in both forecast and impact analyses. The adjustment processes inherent in the econometric input-output system did not mask the differences imbedded in input-output tables derived from different data sources. Since applications of these types of models involve both impact and forecasting exercises, there should be strong motivation for basing the syste on the most accurate set of input-output accounts.     

Removing metals from waste solutions with low rank coals and related materials

Ion exchange media were produced by contacting brown coal, peat or wood sawdust with a solution of calcium hydroxide, preferably as an aqueous slurry of lime. The resultant calcium loading on the media, which ranged up to 8% for sawdust, 12% for peat and to 19% for brown coal, was exchanged for many metals in solution.Preliminary work showed the method to be amenable to extraction of copper, nickel, chromium, cadmium, lead, zinc, mercury, cobalt, silver, iron, manganese, vanadium, germanium, gallium, aluminium, antimony and uranium. For most of the metals more than 99% was removed from I g 1⁻¹ solutions.In more detailed work, confined to calcium loaded brown coal and solutions having metal concentrations more typical of industrial operations, minimum residual metal concentrations of 0.0005 mg l⁻¹ mercury; 0.02 mg 1⁻¹ copper; 0.02 mg 1⁻¹ zinc; <0.05 mg l⁻¹ cadmium; 0.1 mg 1⁻¹ lead and 0.2 mg l⁻¹ manganese were obtained. These results compare favourably with those reported for other relevant processes and there might be operational advantages in the method.The method can be applied either by agitating the calcium loaded media in the solution and then filtering, or by passing the solution through packed beds of the media. Where appropriate, dilute solutions can be up-graded for re-use by stripping the metals from the media which can also be re-used. Alternatively, the loaded media can be combusted and the metals recovered from the residues.The method might be applicable to mine drainage and to effluents from metallurgical processing and electroplating, but more work is required to assess costs.It is suggested that the method is environmentally preferable to other common effluent treatment procedures because it enables collection and recycling of heavy metal pollutants.