Ecosystemic effects of salmon farming increase mercury contamination in wild fish

Net-pen salmon aquaculture has well-known effects on coastal ecosystems: farm waste increases sediment organic content and the incidence of sediment anoxia, supports increased production of deposit-feeding invertebrates, and attracts higher densities of demersal fish and other mobile carnivores. These impacts are widely considered to be localized and transitory, and are commonly managed by imposing a period of fallowing between cycles of production. The implications of these ecosystemic effects for contaminant cycling, however, have not previously been considered. We found elevated levels of mercury in demersal rockfishes near salmon farms in coastal British Columbia, Canada, attributable to a combination of higher rockfish trophic position and higher mercury levels in prey near farms. Mercury concentrations in long-lived species such as rockfishes change over a longer time scale than cycles of production and fallowing, and thus at least some important effects of fish farms may not be considered transitory.     

A Numerical Method for Multiphase Incompressible Thermal Flows with Solid–Liquid and Liquid–Vapor Phase Transformations

ABSTRACT

A numerical method for multiphase incompressible thermal flows with solid–liquid and liquid–vapor phase transformations is presented. The flow is mainly driven by thermocapillary force and vaporization. Based on the level set method and mixture continuum model, a set of governing equations valid for solid, liquid, and vapor phases is derived, considering phase boundary conditions as source terms in the transport equations. The vaporization process is treated as a source term in the continuity equation. The model developed is applied to the laser welding process, where the flow is coupled with optical phenomena. Formation and collapse of a laser-created hole is simulated.     

Self-Cleaning Transparent Dust Shields for Protecting Solar Panels and Other Devices

The development of transparent flexible dust shields using both single- and three-phase electrodynamic shields is reported here for possible application on Mars and Earth to minimize obscuration of solar panels from the deposition of dust. The electrodynamic screens (EDS) are made of transparent plastic sheets, such as polyethylene terephthalate (PET) for its UV radiation resistance, and a set of parallel conducting electrodes made of transparent indium tin oxide (ITO) embedded under a thin transparent film. The basic principle of EDS operation, a simplified mathematical model of particle trajectories, the experimental setup used for testing the screens, and their dust removal efficiencies (DRE) are described. Results of our measurements on dust removal efficiency of EDS as a function of the particle size and electrostatic charge distributions of Mars simulant dust are reported. The results show that the EDS technology has a strong potential for protecting solar panels against dust hazards with DRE higher than 80% for dust. The power requirements will be approximately 10 watts per square meter of the panels when cleaning is needed.     

Development of cardiac prescreening device for rural population using ultralow-power embedded system

The invention is inspired by the desire to understand the opportunities and expectations of developing economies in terms of healthcare. The designed system is a point-of-care (POC) device that can deliver heart-care services to the rural population and bridge the rural-urban divide in healthcare delivery. The product design incorporates several innovations including the effective use of adaptive and multiresolution signal-processing techniques for acquisition, denoising, segmentation, and characterization of the heart sounds (HS) and murmurs using an ultralow-power embedded Mixed Signal Processor. The device is able to provide indicative diagnosis of cardiac conditions and classify a subject into either normal, abnormal, ischemic, or valvular abnormalities category. Preliminary results demonstrated by the prototype confirm the applicability of the device as a prescreening tool that can be used by paramedics in rural outreach programs. Feedback from medical professionals also shows that such a device is helpful in early detection of common congenital heart diseases. This letter aims to determine a framework for utilization of automated HS analysis system for community healthcare and healthcare inclusion.     

Design and Performance of a Laboratory Spray Dryer to Realize Evaporation-Induced Self-Assembly of Nanoparticles

This work discusses the design, development, and performance of an indigenous laboratory spray dryer with a relatively slow drying rate. The drying time of droplets of colloidal silica (5 wt%) and sodium chloride solution (20 wt%) in this spray dryer was nearly 10 s. The present system was composed of a four-jet compressed air nebulizer that generates a droplet size of 2–5 µm with a nebulization rate of nearly 60 mL/h. The generated powder can be collected using a cyclone or a wire mesh collector. Design and characterization of this system as well as characterization of the micrometric self-assembled powder grains obtained by this spray dryer are discussed.     

19—THE EFFECTS OF THE CYLINDER SPEED,DRAFT, AND DELIVERY RATE IN THE JUTE BREAKER CARD

A study of the effects of the breaker-card-cylinder speed and delivery-roller speed on jute-yarn properties is reported. Though machine makers recommend a cylinder speed of 200 rev/min, a speed of 150 rev/min is shown to give a better yarn, even when the production is kept at the same level. Finer fibres absorb more power and yield yarn of higher strength. The strength realization of the fibre is also higher at a lower cylinder speed.     

Improved tire tread compounds using functionalized styrene butadiene rubber-silica filler/hybrid filler systems

Automotive industry is currently looking for an eco-friendly tire with low rolling resistance coefficient (RRc), better traction, wear resistance, and fatigue properties. Presently, solution styrene-butadiene rubber (SSBR)-silica systems are pursued for balancing between traction and RRc. However, the interaction between SSBR and silica is not enough to give satisfactory results. Functionalized-SSBR (FSSBR) leads to better rubber-silica interaction due to introduction of polar groups in the polymer chain. The present study investigates the influence of FSSBR, highly dispersible (HD) silica, and its hybrid filler systems with organically modified nanoclay (ONC) and exfoliated graphene nanoplatelet (xGnP). Both M_H, and Δtorque were higher for the FSSBR-HD silica compound (S1) with the lowest change in storage modulus (∆G') value, due to higher polymer-filler interaction. S1 exhibited 16% ice traction and 12% wet traction improvement with 29% lower rolling resistance over SSBR-silica compound. S1 showed the best wet traction rating and wear resistance. Replacing small portion of silica by ONC and xGnP improved the properties further. At 5 phr of nanofiller, TEM images revealed well-dispersed nanofillers in the FSSBR matrix. The xGnP compound showed the least crack growth. For both the cases, abradability decreased with higher nanofiller amount, due to better reinforcement of the rubber.