Evaluation of the performance of sulfonated esparto grass lignin as a plasticizer-water reducer for cement

The objective of the work described in this first paper of a series is an investigation of the preparation of a sulfonated esparto grass lignin (SEL) and its behavior as a plasticizing-water-reducing agent for cement-water systems. SEL is prepared by extracting the lignin from the black liquor of a soda esparto grass pulping process and then sulfonating it with a mixture of sodium sulfite and formaldehyde.Analyses and characterization of SEL carried out with high-performance size exclusion chromatography (HPSEC), reversed phase chromatography (RPC), infrared spectrometry and chemical methods show that both the molecular weight average and the combined sulfur content are relatively high. Moreover, HPSEC shows that SEL has a relatively more uniform molecular weight distribution (MWD) than the commercial products obtained from the sulfite wood pulping process. On the other hand, SEL could reduce the water content, improve the workability and compressive strength of mortars. SEL also permits a very low rate of slump loss of cements without excessive extension of the final set time.     

Vibrational Diver

The paper is concerned with dynamics of light solid in cavity with liquid subjected to rotational vibration in the external force field. New vibrational phenomenon – diving of a light cylinder to the cavity bottom is found. The experimental investigation of a horizontal annulus with a partition has shown that under vibration a light body situated in the upper part of the layer is displaced in a threshold manner some distance away from the boundary. In this case the body executes symmetric tangential oscillations. An increase of the vibration intensity leads to a tangential displacement of the body near the external boundary. This displacement is caused by the tangential component of the vibrational lift force, which appears as soon as the oscillations lose symmetry. In this case the trajectory of the body oscillatory motion has the form of a loop. The tangential lift force makes stable the position of the body on the inclined section of the layer and even in its lower part. A theoretical interpretation has been proposed, which explains stabilization of a quasi-equilibrium state of a light body near the cavity bottom in the framework of vibrational hydromechanics.     

Spectral analysis of thermoelastic systems under nonclassical thermal models

We study some spectral properties of the solutions to generalized thermoelastic systems under Lord–Shulman, Green–Lindsay, and Green–Naghdi of type-II models. First, we prove that the linear operator of each model has compact resolvent and generates a C₀?semigroup in an appropriate Hilbert space. We also show that there is a sequence of generalized eigenfunctions of the linear operator that forms a Riesz basis. By a detailed spectral analysis, we obtain the expressions of the spectrum and we deduce that the spectrum-determined growth condition holds. Therefore, if the imaginary axis is not an asymptote of the spectrum, we prove that the energy of each model decays exponentially to a rate determined explicitly by the physical parameters. Finally, some simulations are given for each model to support our results.     

Three novel angiotensin I-converting enzyme (ACE) inhibitory peptides from cuttlefish (Sepia officinalis) using digestive proteases

The angiotensin I-converting enzyme (ACE) inhibitory activities of protein hydrolysates prepared from muscle of cuttlefish (Sepia officinalis) by treatment with various digestive proteases were investigated. The most active hydrolysate was obtained with the crude protease extract from the hepatopancreas of cuttlefish (64.47 ± 1.0% at 2 mg of dry weight/ml) with a degree of hydrolysis of 8%. By gel filtration on Sephadex G-25 and RP-HPLC on C18 column, three novel peptides with high ACE-inhibitory activity were purified and their molecular masses and amino acid sequences were determined. The three peptides Val-Tyr-Ala-Pro, Val-Ile-Ile-Phe and Met-Ala-Trp with IC₅₀ values of 6.1, 8.7 and 16.32 μM, respectively, were novel ACE-inhibitory peptides. Lineweaver–Burk plots suggest that the three purified peptides act as non-competitive inhibitors against ACE. These results suggest that some peptides from cuttlefish could be a beneficial ingredient for nutraceuticals against hypertension.     

An ice rink floor thermal model suitable for whole-building energy simulation analysis

This paper presents a thermal model for an ice rink floor system that is integrated into EnergyPlus, a whole-building energy simulation tool, to improve design, evaluation, and operation of ice rink facilities. The developed ice rink floor thermal model, based on the conduction transfer function method, is validated against experimental data obtained under laboratory testing conditions. Two control strategies for indoor ice rink floor systems were modeled and evaluated including a brine temperature control strategy and an ice surface temperature control strategy.     

High performance sensorless speed vector control of SPIM Drives with on-line stator resistance estimation

The aim of this paper is to implement a sensorless Indirect Stator Field Oriented Control (ISFOC) of Single-Phase Induction Motor Drive (SPIMD) with stator resistance tuning. The proposed method for the estimation of speed is based only on measurement of stator currents. A very simple identification algorithm using d-axis stator current error for identifying the stator resistance is proposed. Experimental results for SPIMD are presented and analyzed by using a dSpace system with DS1104 control board based on the Digital Signal Processor (DSP) TMS320F240. Simulated results are compared with experimental results on a test 1.1 kW SPIM setup. The agreement between simulated and experimental results proves the validity of the proposed method.     

Optimal parameter selection for qualitative regional erosion risk monitoring: A remote sensing study of SE Ethiopia

Arid and semi-arid regions are susceptible to high levels of erosion. A rapid and cost effective methodological erosion assessment for these regions is required to describe and monitor the processes that control erosion. This study uses remote sensing to describe the contribution of several factors that control erosion. Topography, land use, vegetation density, soil properties and climatic proxies are used to determine erosion risk and to provide basic maps of water and soil conservation practices. A hierarchical decision tree is used to sum and combine the weight of parameters controlling the erosion. The assigned weights of each spatial unit express the susceptibility to erosion. We focus on the catchment basin of the Maleka Wakena reservoir, located in the southeastern portion of the main Ethiopian Rift, where erosion is the major environmental problem. Three different combinations of the dominant controlling factors are yielded in this study. In order to optimize the qualitative erosion risk assessment, each combination is discussed and evaluated depending on the contribution of parameters involved in the erosion process.     

Effect of Quillaja saponaria dietary administration on colour, oxidative stability and volatile profile of muscle longissimus dorsi of Barbarine lamb

Eighteen Barbarine lambs were assigned during 77days to three dietary treatments (n=6): control, oat hay ad libitum and 400g of concentrate; QS60 and the QS90 control diet supplemented with 60mg and 90mg Quillaja saponaria (QS) bark extract/kg dry matter, respectively. The analysis of pre-frozen longissimus dorsi muscle showed that the QS90 treatment reduced meat redness (a*) and saturation (C*) measured after 2h of blooming. It also reduced the rate of decrease in a* values (P=0.02) during 14days of refrigerated storage. Supplementation with QS extended meat colour stability by reducing (P<0.05) the rate of increase in hue angle (H*) values. Neither the rate of metmyoglobin accumulation at the meat surface nor lipid peroxidation over storage duration differed between treatments. The overall meat volatile compound profile was similar between the groups. We conclude that supplementing QS affects meat colour development at the meat surface and extends its stability without producing detrimental effects on meat volatile compounds.     

Fundamentals of technology diffusion and mobile phone case study

The fundamentals of technology diffusion are introduced in this paper. Mathematical and heuristic (loose) modeling are defined and illustrated with real data. Starting with the embryonic phase, diffusion undergoes growing and mature phases and ends in the aging phase. The cumulative adoption function (of time) denoting the total number of users of a certain product is the output of the diffusion model used to either predict future trends (e.g. sales) or estimate certain model parameters. Problems often encountered in mathematical modeling and analysis are presented. Some of these shortcomings can be alleviated through loose modeling. A case study of mobile telephone diffusion in Finland is presented to illustrate some of the modeling principles and analysis.