Settling of superparamagnetic silica encapsulated DNA microparticles in river water

Particle tracers are sometimes used to track sources and sinks of riverine particulate and contaminant transport. A potentially new particle tracer is ~200 nm sized superparamagnetic silica encapsulated DNA (SiDNAFe). The main objective of this research was to understand and quantify the settling and aggregation behaviour of SiDNAFe in river waters based on laboratory settling experiments. Our results indicated, that in quiescent conditions, more than 60% of SiDNAFe settled within 30 h, starting with a rapid settling phase followed by an exponential-like slow settling phase in the three river waters we used (Meuse, Merkske, and Strijbeek) plus MilliQ water. In suspensions of 1000× higher particle concentrations, the hydrodynamic diameter (Dh-DLS) of SiDNAFe increased over time, with its polydispersity index (PDI) positively correlated with particle size. From these observations, we inferred that the rapid SiDNAFe settling was mainly due to homo-aggregation and not due to hetero-aggregation (e.g., with particulate matter present in river water). Incorporating a first-order mass loss term which mimics the exponential phase of the settling in quiescent conditions seems to be an adequate step forward when modelling the transport of SiDNAFe in river injection experiments. Furthermore, we validated the applicability of magnetic separation and up-concentration of SiDNAFe in real river waters, which is an important advantage for carrying out field-scale SiDNAFe tracing experiments.Water ResourcesEnvironmental Fluid Mechanic

Mechanical performance characterization of lignin-modified asphalt mixture

Lignin, as a bio-based waste, has been utilized in the asphalt industry due to various advantages. This study aimed to investigate the effects of two lignin products (lignin powder and lignin fiber) on the mechanical properties of asphalt mixtures. The raveling, rutting, thermal and fatigue cracking resistance, and moisture susceptibility of different asphalt mixtures were respectively evaluated by the Cantabro test, wheel loading tracking test, semicircular bending test, four-point beam bending test, and freezing-thaw cyclic test. Results show that asphalt mixture with lignin powder-modified asphalt improved the overall mechanical performance. However, lignin fiber showed contradictory effects on certain mechanical properties, i.e., improved rutting resistance and thermal cracking resistance of asphalt mixture, degraded abrasion resistance, fatigue performance, and moisture stability. Therefore, cautions need to be taken when incorporating lignin fiber into asphalt mixture.Pavement Engineerin

Knitting 4D garments with elasticity controlled for body motion

In this paper, we present a new computational pipeline for designing and fabricating 4D garments as knitwear that considers comfort during body movement. This is achieved by careful control of elasticity distribution to reduce uncomfortable pressure and unwanted sliding caused by body motion. We exploit the ability to knit patterns in different elastic levels by single-jersey jacquard (SJJ) with two yarns. We design the distribution of elasticity for a garment by physics-based computation, the optimized elasticity on the garment is then converted into instructions for a digital knitting machine by two algorithms proposed in this paper. Specifically, a graph-based algorithm is proposed to generate knittable stitch meshes that can accurately capture the 3D shape of a garment, and a tiling algorithm is employed to assign SJJ patterns on the stitch mesh to realize the designed distribution of elasticity. The effectiveness of our approach is verified on simulation results and on specimens physically fabricated by knitting machines. Accepted Author ManuscriptMaterials and ManufacturingMechatronic Desig

Maximizing eco-environmental gains: Exploring underground wastewater treatment plants in Beijing for sustainable urban water management

This study assessed the evolution of wastewater systems during the rapid urbanization of Beijing, with special focuses on the carbon footprints and growing underground WWTPs (u-WWTPs). Specifically, the Bishui plant (in situ constructed u-WWTP) was assessed in detail regarding eco-environmental benefits. Our results showed that, the direct emission intensity of 65 WWTPs decreased from 0.47 to 0.24 kg CO2eq/m3, when the electricity intensity increased from 0.22 to 0.39 kWh/m3 from 2010 to 2020. Bishui u-WWTP emitted 36.6 kt CO2eq/year (0.09 kg CO2eq/m3), with electricity intensity of 0.43 kg CO2eq/m3. Additionally, compare to the hypothetical relocating scenario, it saved 6.67 × 104 m2 land and 33.0 kt CO2eq/year, and the created urban river carries 6.5 × 1013 J/year heat outside town. The evaluation and balance of choice for conventional or underground WWTP should be made case by case. However, this study demonstrated that u-WWTP is not only a construction manner, but a sustainable management model with positive eco-environment effects, algin with future city expansion, and circular economy visions.Water ManagementSanitary Engineerin

Impacts of ridge with plastic mulch-furrow irrigation on soil salinity, spring maize yield and water use efficiency in an arid saline area

The inadequate soil and water management has resulted in ecological and environmental problems in Hetao Irrigation District, which is characterized by low precipitation, high evaporation and soil salinity issues. A two-year field experiment was conducted to investigate the effects of the combined application of irrigation methods, irrigation amounts and plastic mulching modes on soil moisture, soil salinity, and water use efficiency of spring maize. This experiment included four treatments: (i) border irrigation partially mulched by plastic film with full irrigation amount (CK), (ii) ridge-furrow irrigation not mulched by plastic film with high irrigation amount (NRF), (iii) ridge with plastic mulch-furrow irrigation with high irrigation amount (PRF), (iv) ridge with plastic mulch-furrow irrigation with low irrigation amount (PRL). The results demonstrated that soil water and soil salinity mainly changed in the upper 80 cm soil layer. The proportion of the amount of deep percolation in the total growing season ranged from 9.3% to 29.5% and the highest deep percolation amount appeared in CK. Less irrigation amount generally resulted in a higher salt accumulation in the upper 40 cm soil layer. At harvest, the highest salt accumulation appeared in PRL and the lowest salt accumulation appeared in PRF among the three ridge-furrow irrigation treatments. Compared with the CK treatment, the average grain yields in the PRF, PRL and NRF treatments were increased by 29.6%,12.2% and 14.4% in 2015, and increased by 5.5%, 4.2% and 2.5% in 2016, respectively. The highest water use efficiency was found in the treatment with PRF in 2015 growing season, and in the treatment with PRL in 2016 growing season. Irrigation water use efficiency was lower in PRF than in PRL, whereas higher than in CK and NRF. Fully considering maize yield, soil water storage, soil salt balance and water use efficiency in the Hetao Irrigation District, ridge with plastic mulch-furrow irrigation with about 300 mm of irrigation water can be recommended as the effective soil and water management practice. (C) 2017 Published by Elsevier B.V