Membrane treatment of side-stream cooling tower water for reduction of water usage

A pilot study was conducted to determine whether membrane treatment on a side stream of recirculating cooling-tower water could reduce overall water usage and discharge. The treated permeate was returned to the cooling tower while the concentrate was discharged to the sanitary sewer. Flow rates, pressures and water chemistry were monitored. The pilot demonstrated potential substantial water savings. Maximum make-up water and discharge reduction were 16% and 49%, respectively. As high as possible permeate recovery is needed to maximize water conservation. Silica scaling on the membranes limited water savings in this pilot. Development of membranes with a solute-rejection capacity less than the 92% average of the membranes used in the pilot would assist in optimizing water savings. Decreased water outlays compensated for the additional energy used by membrane treatment. Scaling control is critical for economic operation.     

Reduced Carbon and Energy Footprint in Highway Operations: The Highway Energy Assessment (HERA) Methodology

Global demand for mobility is increasing and the environmental impact of transport has become an important issue in transportation network planning and decision-making, as well as in the operational management phase. Suitable methods are required to assess emissions and fuel consumption reduction strategies that seek to improve energy efficiency and furthering decarbonization. This study describes the development and application of an improved modeling framework – the HERA (Highway EneRgy Assessment) methodology – that enables to assess the energy and carbon footprint of different highways and traffic flow scenarios and their comparison. HERA incorporates an average speed consumption model adjusted with a correction factor which takes into account the road gradient. It provides a more comprehensive method for estimating the footprint of particular highway segments under specific traffic conditions. It includes the application of the methodology to the Spanish highway network to validate it. Finally, a case study shows the benefits from using this methodology and how to integrate the objective of carbon footprint reductions into highway design, operation and scenario comparison.     

Activated carbons as potentially useful non-nutritive additives to prevent the effect of fumonisin B1 on sodium bentonite activity against chronic aflatoxicosis

Aflatoxin B₁ (AFB₁) and fumonisin B₁ (FB₁) are mycotoxins that often co-occur in feedstuffs. The ingestion of AFB₁ causes aflatoxicosis in humans and animals. Sodium bentonite (NaB), a cheap non-nutritive unselective sequestering agent incorporated in animal diets, can effectively prevent aflatoxicosis. Fumonisins are responsible for equine leukoencephalomalacia and porcine pulmonary oedema, and often have subclinical toxic effects in poultries. Fumonisin B₁ and aflatoxin B₁ are both strongly adsorbed in vitro on sodium bentonite. Co-adsorption studies, carried out with a weight ratio of FB₁ to AFB₁ that mimics the natural occurrence (200:1), showed that FB₁ greatly decreases the in vitro ability of NaB to adsorb AFB₁. The ability of two activated carbons to adsorb FB₁ was also investigated. Both carbons showed high affinity for FB₁. A complex behaviour of the FB₁ adsorption isotherms with pH was observed. In vitro results suggest that under natural contamination levels of AFB₁ and FB₁, a mixture of activated carbon and sodium bentonite might be potentially useful for prevention of sub-acute aflatoxicosis.     

Modification of the La0.6Sr0.4CoO3 coating deposited on ferritic stainless steel by spray pyrolysis after oxidation in air at high temperature

The behaviour of La_0.6Sr_0.4CoO₃ applied to ferritic stainless steel (AISI 430) by spray pyrolysis was investigated after oxidation at 800 °C in air. The film was characterized with regard to its morphology, structure and adhesion. The film was regular over the entire surface and adhered well to the metallic substrate. Oxidation modified the film structure, forming an oxide (SrCrO₄) in the metal/coating region due to Sr diffusion from the coating and Cr diffusion from the metallic substrate. A thermodynamic computational simulation confirmed the formation and stability of this oxide.     

Effects of docosahexaenoic acid on retinal development: Cellular and molecular aspects

We have recently shown that docosahexaenoic acid (DHA) is necessary for survival and differentiation of rat retinal photoreceptors during development in vitro. In cultures lacking DHA, retinal neurons developed normally for 4 d; then photoreceptors selectively started an apoptotic pathway leading to extensive degeneration of these cells by day 11. DHA protected photoreceptors by delaying the onset of apoptosis; in addition, it advanced photoreceptor differentiation, promoting opsin expression and inducing apical differentiation in these neurons. DHA was the only fatty acid having these effects. Mitochondrial damage accompanied photoreceptor apoptosis and was markedly reduced upon DHA supplementation. This suggests that a possible mechanism of DHA-mediated photoreceptor protection might be the preservation of mitochondrial activity; a critical amount of DHA in mitochondrial phospholipids might be required for proper functioning of these organelles, which in turn might be essential to avoid cell death. Müller cells in culture appeared to be involved in DHA processing: they took up DHA, incorporated in into glial phospholipids, and channeled it to photoreceptors in coculture. Both Müller cells, when cocultured with neuronal cells, and the glial-derived neurotrophic factor (GDNF) protected photoreceptors from cell death. These results suggest that glial cells may play a central role in regulating photoreceptor survival during development through the provision of trophic factors. The multiple effects of DHA on photoreceptors suggest that in addition to its structural role, DHA might be one of the trophic factors required by these cells.     

Montmorillonite as support for peroxide in the melt grafting of maleic anhydride onto polypropylene

Grafting of maleic anhydride onto polypropylene was performed in a Haake torque rheometer, in the presence of organically modified montmorillonite, MMT (used as support for the peroxide), according to a 2³ factorial design, where the maleic anhydride concentration (C_MA), peroxide concentration (C_per) and reaction time (t_r) were varied. For comparison, the reaction in the absence of MMT was also conducted. Polypropylene degradation was assessed by parallel plate rheometry and size exclusion chromatography (SEC) and percentage of reacted maleic anhydride (%MA_g) was obtained by titration and FTIR spectroscopy. The results showed differences in both systems, conventional and in the presence of MMT. The structure of polypropylene grafted with maleic anhydride, PP‐g‐MA, indicates longer branches are formed in the presence of MMT compared to in its absence, demonstrated by FTIR analysis. As in conventional reaction systems, an increase in C_per caused an increase in %MA_g and a reduction in molar mass. The variable C_MA showed to be not significant in the grafting reaction in the presence of MMT, even at high DCP levels, at a 5% significance level. On the other hand, increase in C_MA resulted in significant increase in viscosity. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44134.     

基于SR7265硬件的虚拟锁相放大器、频谱仪、阻抗计和半导体参数分析仪

锁相放大器是用来测量微弱信号的专用仪器.即使噪音上千倍于被测信号,通过锁相放大器,也能得到精确结果.随着数字信号处理技术在仪器中的应用,可编程仪器变得越来越灵活.结合虚拟仪器的技术,论文通过对SR7265的硬件重新编程,在同一个硬件上实现了虚拟锁相放大器、虚拟频谱仪、虚拟阻抗计和虚拟半导体参数分析仪等等功能.本虚拟仪器采用了4层的逻辑结构.同样的功能也在一个FPGA板上成功地部署.     

Effect of surface roughness and stainless steel finish on Listeria monocytogenes attachment and biofilm formation

The purpose of this study was to evaluate the effect of surface roughness (Ra) and finish of mechanically polished stainless steel (Ra = 0.26 +/- 0.05, 0.49 +/- 0.10, and 0.69 +/- 0.05 microm) and electropolished stainless steel (Ra = 0.16 +/- 0.06, 0.40 +/- 0.003, and 0.67 +/- 0.02 microm) on Listeria adhesion and biofilm formation. A four-strain cocktail of Listeria monocytogenes was used. Each strain (0.1%) was added to 200 ml of tryptic soy broth (TSB), and coupons were inserted to the mixture for 5 min. For biofilm formation, coupons with adhesive cells were incubated in 1:20 diluted TSB at 32 degrees C for 48 h. The experiment was performed by a randomized block design. Our results show that the level of Listeria present after 48 h of incubation (mean = 7 log CFU/cm2) was significantly higher than after 5 min (mean = 6.0 log CFU/cm2) (P < 0.01). No differences in initial adhesion were seen in mechanically finished (mean = 6.7 log CFU/cm2) when compared with electropolished stainless steel (mean = 6.7 log CFU/cm2) (P > 0.05). Listeria initial adhesion (values ranged from 5.9 to 6.1 log CFU/cm2) or biofilm formation (values ranged from 6.9 to 7.2 log CFU/cm2) was not significantly correlated with Ra values (P > 0.05). Image analysis with an atomic force microscope showed that bacteria did not colonize the complete surface after 48 h but were individual cells or grouped in microcolonies that ranged from 5 to 10 microm in diameter and one to three cell layers in thickness. Exopolymeric substances were observed to be associated with the colonies. According to our results, electropolishing stainless steel does not pose a significant advantage for food sanitation over mechanically finished stainless steel.