A Taxonomy for MAC Protocols in Wireless Sensor Networks Based on Traffic Prioritization

Wireless Personal Communications - Various media access control (MAC) protocols have been developed to deal with the heterogenous traffic in wireless sensor networks (WSN). In many emerging...     

The ultrafiltration molecular weight cut-off has a limited effect on the concentration and protein profile during preparation of human milk protein concentrates

Optimizing protein intake for very low birth weight (<1,500 g) infants is fundamental to prevent faltering postnatal growth with the potential association of impaired neurodevelopment. The protein content of human milk is not sufficient to support the growth of very low birth weight infants. To meet their elevated protein requirements, human milk is currently fortified using typically bovine milk-based protein isolates (>85% on a dry basis). However, these products have several limitations for use in this vulnerable population. To overcome the shortcomings of bovine milk-based protein supplement, a human milk protein concentrate (HMPC) was developed. In preliminary attempts using 10 kDa ultrafiltration (UF) membranes, it was not possible to reach the protein content of commercial protein isolates, presumably due to the retention of human milk oligosaccharides (HMO). Consequently, it was hypothesized that the use of a UF membrane with a higher molecular weight cut-off (50 kDa rather than 10 kDa) could improve the transmission of carbohydrates, including HMO, in the permeate, thus increasing the protein purity of the subsequent HMPC. The results showed that permeate fluxes during the concentration step were similar to either UF molecular weight cut-off, but the 50-kDa membrane had a higher permeate flux during the diafiltration sequence. However, it was not sufficient to increase the protein purity of the human milk retentate, as both membranes generated HMPC with similar protein contents of 48.8% (10 kDa) and 50% (50 kDa) on a dry basis. This result was related to the high retention of HMO, mainly during the concentration step, although the diafiltration step was efficient to decrease their content in the HMPC. As the major bioactive proteins (lactoferrin, lysozyme, bile salt stimulated lipase, and α1-antitrypsin) in human milk were detected in both HMPC, the 50-kDa membrane seems the most appropriate to the preparation of HMPC in terms of permeation flux values. However, improving the separation of HMO from proteins is essential to increase the protein purity of HMPC.     

Energy conservation in US buildings: Solving the high potential/low adoption paradox from a behavioural perspective

The US building sector can ‘produce’ 30–50% of its energy needs by more efficient use of energy, ie by conservation. The cost of such energy conservation is usually below that of imported oil or new electric generation capacity. Yet, paradoxically, consumer adoption of this type of ‘energy’ is quite low. This stems from energy analysis traditionally dominated by engineering and economic perspectives, and ignoring a critically relevant behavioural perspective. Unless all three perspectives are integrated, little can be expected in the way of speedy market penetration of energy conservation. In this article the engineering, economic and behavioural perspectives are discussed, and the importance of integration is emphasized. The framework for diffusion of innovations is shown to be useful in an understanding of how demand for energy conservation forms and spreads. Specific recommendations to speed the adoption of energy conservation are outlined.     

Analysis of shear stresses in bulk carriers

A method is given for calculating the shear stress distribution over a ship section of a bulk carrier. The method is programmed for the Alexandria University IBM computer. The ship section is considered with minimum idealization to the double bottom structure so as to obtain realistic values of the shear stresses.Several ship section configurations are studied and the results are analysed. A summary of the analysis is given together with a numerical example. A simplified expression is developed for calculating an approximate value of the maximum shear stress in the side shell plating. The results of this expression compare favourably with computer results.The necessary conditions to safeguard against shear buckling and yielding of side shell, hopper and top wing tanks are specified.It is shown that: (i) The side shell plating between the hopper and top wing tanks may be subjected to high shear stresses since it carries about 35% of the total shearing force, (ii) The hopper and top wing tanks may be subjected to unfavourable stress conditions.     

Effect of structure on the thermal stability of photocurable urethane acrylate formulations

The effect of structural segments on the thermal stability of photocurable urethane acrylates was studied. A series of model compounds, where one segment of the molecular structure was varied at a time while keeping the remainder of the molecule unchanged, was tested for thermal stability. The results from this study indicate a prominent equivalent weight effect: Increasing the equivalent weight decreases the thermal stability within a given series of model compounds. Polyol-based urethanes were found to be more stable than their amine counterparts. Of the hydroxy-terminated starting materials, polycaprolactones were found to produce the greatest thermal stability, whereas polyethers resulted in the least stable photocurable materials. The diisocyanate segment exhibits a marked effect on the thermal stability of the cured material also. Surprisingly, the dicycloaliphatic diisocyanates resulted in greater stability than the aromatic diisocyanates, while the monocycloaliphatic diisocyanates yielded the least stable materials in the model compound series tested.     

Citation Ootprint Analysis Part I: UK and US Chemical Engineering Academics

A novel method of displaying the publication and citation characteristics of outputs of researchers using a graphical "footprint" has been developed. Its first application has been to compare the publication and citation characteristics of a small group of top UK, and US academic chemical engineers. The footprint demonstrates the Relationship Factors of publications in a number of related disciplines, as defined by ISI's Journal Citation Reports. The technique has been used to compare both individual academics and each national group as a whole. The results clearly show that US academic chemical engineers are far more interdisciplinary in their output than their UK counterparts. The technique has a number of potential applications, including tracking changes in a discipline over time, tracking individual academics' output over time, and comparing different disciplines for their interdisciplinarity.     

Altitude control in simulated flight using 3‐D objects and terrain texture

Abstract— In this study, the effects of manipulating the properties of 3‐D objects and terrain texture on the control of altitude in simulated flight has been investigated. 3‐D objects were found to be as effective as terrain texture for controlling altitude, and this result was interpreted as suggesting that both terrain texture and 3‐D objects can serve as effective carriers of information about motion parallax and optical expansion and contraction. The present results, which were obtained using a vertically defined flight task, are inconsistent with the findings of Patterson et al., who reported that 3‐D objects were more effective than terrain texture for controlling a horizontally defined heading task. The present results indicate that, when terrain texture is present, the motion parallax or optical expansion associated with the presence of 3‐D objects does not improve altitude control.     

Radiation Synthesis of Carboxymethyl Cellulose Hydrogels for Removal of Organic Contaminants from Its Aqueous Solution

Preparation of hydrogels based on carboxymethyl cellulose (CMC) using direct radiation grafting technique for removal of organic contaminant such as 4‐chlorophenol and 2,4‐dichlorophenoxyacetic acid (2,4‐D) was carried out. The prepared hydrogels which are composed of individual radiation grafting of methacrylic acid onto CMC to form poly(CMC/MAA) the other hydrogel composed of binary acrylamide/methacrylic acid grafted onto CMC to form poly(CMC/MAA:AAm) hydrogels. The two selected composition poly(CMC/MAA:AAm) (1/60:40 wt%) poly(CMC/MAA) (1:20) wt% hydrogels due to its high chelating properties obtained from our previous work by the same authors. The properties of the selected two prepared hydrogels were evaluated by using different analytical tools such as Fourier transform infrared (FTIR), X‐ray diffraction (XRD), and thermogravimetric analysis (TGA). The gel (%) and the swelling behavior of poly(CMC/MAA:AAm) is higher than poly(CMC/MAAc) hydrogel. It is found that the adsorption capacity of poly(CMC/MAA) hydrogel (1:20 wt%) toward 4‐chlorophenol and 2,4 dichlorophenoxy acetic acid was higher than that of poly(CMC/MAA:AAm) (1/60:40 wt%) hydrogel. Also The obtained results showed that the adsorption capacity of both poly(CMC/MAA:AAm) (1/60:40 wt%) and poly(CMC/MAA) (1:20) wt% hydrogels toward 2,4 dichlorophenoxy acetic acid was higher than of 4‐chlorophenol. J. VINYL ADDIT. TECHNOL., 26:362–369, 2020. © 2019 Society of Plastics Engineers     

Cold atmospheric plasma decontamination of the pericarps of fruit

This investigation describes the inactivation by cold atmospheric plasmas of one pathogenic and three spoilage organisms on the pericarps of mangoes and melons. The operating voltage necessary for efficient microbial decontamination of fruit pericarps was first established using Escherichia coli at a concentration of 10(7) CFU/cm2 on the surface of mango. It was found that, when the plasma was sustained slightly above its breakdown voltage of 12 kV (peak to peak), no inactivation was detected when cells were plated onto tryptone soya extract agar (TSA). However, when plated onto eosin methylene blue agar, sublethal injury corresponding to approximately 1 log reduction was achieved, whereas on TSA supplemented with 4% NaCl a greater reduction of 1.5 log was revealed. When the voltage was increased by 33% to 16 kV, a reduction in cell counts of 3 log was achieved on all three plating media. Further investigations at these new operating conditions were conducted using a range of spoilage microorganisms (Saccharomyces cerevisae, Pantoea agglomerans, and Gluconacetobacter liquefaciens) all at a surface concentration of 106 CFU/cm2 on the pericarps of mango and melon. P. agglomerans and G. liquefaciens were reduced below the detection limit (corresponding to 3 log) after only 2.5 s on both fruits, whereas E. coli required 5 s to reach the same level of inactivation. S. cerevisae was the most resistant organism studied and was reduced in numbers below the detection limit after 10 s on mango and 30 s on melon. The optical emission spectra generated by the cold atmospheric plasma at both high and low operating voltages were compared in order to identify putative lethal species. It was shown that an increase in the applied voltage led to more efficient production of reactive plasma species, particularly oxygen atoms, and the production of oxygen atoms was related to the level of bacterial inactivation achieved. Production of atomic oxygen could be used as an indicator of inactivation efficiency for scaling up cold plasma systems for whole fruit.     

The role of offsets in a post-Kyoto climate agreement: The power sector in China

This paper considers how an offset scheme specific to the electricity generation sector could incentivize emissions cuts while avoiding the problems encountered by the Clean Development Mechanism (CDM). It proposes an approach to project evaluation based on measures of additionality, economic viability and contribution to sustainable development specific to this sector and re-evaluates 460 registered CDM projects in China that generate electricity using wind, natural gas or small hydro. It concludes that many small hydro schemes would be viable without the CDM subsidy. Although these projects have zero emissions from operations, offsets issued to projects that are viable without subsidy permit increased emissions in developed countries and lead to a net increase in global emissions. To provide some indication of the sustainable development benefits that CDM projects bring to their host countries, the paper includes estimates of the projects’ benefit to public health due to the reduced use of coal for generation. The paper provides insights into the economics of projects and their value to host countries that are missed by the official CDM methodologies. It contributes to the debate over the design of sector-specific offset schemes that may be part of a new global agreement on combating climate change.