Use of zeolite-rich rocks and waste materials for the production of structural lightweight concretes

This paper aims at testing the use of mixtures constituted by natural zeolitized products and SiC-bearing industrial wastes (sludge deriving from polishing of porcelain stoneware tiles, hereafter DPM) for the production of lightweight expanded aggregates as constituents of structural and/or thermo-insulating lightweight concretes. Two commercial products have been used as zeolite natural source: Cab70 (Yellow facies of Campanian Ignimbrite) and IZclino (Turkish clinoptilolite-rich epiclastite). Different amounts of a calcareous material (Pozzano limestones — hereafter CP) from the Sorrento peninsula (Naples — Italy) were also added to a Cab70–DPM mixture. All raw materials were characterized by means of mineralogical (XRPD) and chemical (XRF) analyses. All the products and mixtures were tested from a technological point of view by means of fusibility and firing tests in order to evaluate the expanding properties. It was evidenced that the expansion of the mixture was deeply depending on the occurrence of SiC in the industrial waste. The addition of CP (10 wt.%) to the mixtures accounts for an even increased expansion, though this is accompanied by a worsening of the mechanical features of the material.These results along with literature data allowed to select 3 mixtures (70% Cab70–30% DPM, 70% IZclino–30% DPM, 60% Cab70–30% DPM–10% CP) and each of them was used for the preparation of 5 l of lightweight aggregates afterward employed for the manufacture of lightweight concretes. It was remarked that natural zeolitized materials mixed with DPM (30 wt.%) can provide lightweight aggregates with densities ranging between 0.8 and 1.0 g/cm³ suitable for the preparation of structural lightweight concretes. The addition to the mixture of CP (10 wt.%) produces less dense aggregates (0.6–0.7 g/cm³) potentially useful for the manufacture of thermo insulating lightweight concretes.     

Hydroprocessing peculiarities of Fischer–Tropsch syncrude

When catalysts developed for crude oil hydroprocessing are used for syncrude, there are syncrude-specific peculiarities to consider. These relate to differences in the nature and abundance of heteroatoms, olefins, metal species, waxes and aqueous products. Some important aspects are (a) heat release during naphtha and distillate hydroprocessing is very high, but wax hydrocracking is almost isothermal; (b) syncrude is sulphur-free and the use of sulphided base-metal hydroprocessing catalysts require the addition of sulphur-containing compounds to the syncrude; (c) oxygenates strongly adsorb on some catalytic surfaces to affect catalytic behaviour; (d) carbonyl–carboxylic acid interconversion and water produced by hydrodeoxygenation (HDO) may result in catalyst degradation by acid and hydrothermal attack; (e) carboxylic acids in syncrude result in equipment corrosion and catalyst leaching; (f) metal carboxylates are the main metal-containing species in syncrude and are not removed by hydrodemetallation (HDM) catalysis, but by thermal decomposition.     

Esthetic decision‐making: How do people select colours for real settings?

A feature of the empirical literature in colour psychology is that little attention has been given to how people in real settings engage in colour selection. Surprisingly, with rare exceptions, we know almost nothing about this. Besides its theoretical significance within psychology, this question has practical implications for industries where colour choice is important. A study is reported into that most ubiquitous of activities, selecting a paint colour for the home. This used a retrospective method supported by qualitative data analysis (NVivo) in which participants described their process of colour selection. The results indicate a process that is far from uniform, but one that consists of two essential stages. The first involves arriving at what we refer to as an affective specification of the qualities sought. Once constructed, this leads to the second stage of matching colour attributes to that specification. Selecting a wall colour emerges as a surprisingly complex process, and one that corresponds more closely to a search than to a simple affective choice. A parallel is drawn with decision research, particularly the field of naturalistic decision‐making. From participants' reports, colour selection also emerges as a process that women appear to understand better than men. © 2007 Wiley Periodicals, Inc. Col Res Appl, 33, 55–60, 2008     

Genotoxic effect of Physalis angulata L. (Solanaceae) extract on human lymphocytes treated in vitro

Physalis angulata L (Solanaceae) is a medicinal plant from North of Brazil, whose different extracts and infusions are commonly used in the popular medicine for the treatment of malaria, asthma, hepatitis, dermatitis and rheumatism. However, the genotoxic effects of P. angulata on human cells is not well known. The main purpose of the present study was to evaluate the in vitro genotoxic effects of aqueous extract of P. angulata using the comet assay and the micronucleus assay in human lymphocytes provided from 6 healthy donors. Treatments with P. angulata extracts were performed in vitro in order to access the extent of DNA damage. The comet assay has shown that treatments with P. angulata at 0.5, 1.0, 2.0, 3.0 and 6.0 microg/mL in culture medium were genotoxic. Lymphocytes treated with P. angulata at the concentrations of 3.0 and 6.0 microg/mL in culture medium showed a statistically significant increase in the frequency of micronucleus (p<0.05), however, the cytokinesis blocked proliferation index (CBPI) was not decreased after P. angulata treatment. In conclusion, the present work demonstrated the genotoxic effects of P. angulata extract on human lymphocytes in vitro.     

Nisin expression production from Lactococcus lactis in milk whey medium

BACKGROUND: Nisin is a commercially available bacteriocin produced by Lactococcus lactis ATCC 11454 and used as a natural agent in the biopreservation of food. In the current investigation, milk whey, a byproduct from dairy industries was used as a fermentation substrate for the production of nisin. Lactococcus lactis ATCC 11454 was developed in a rotary shaker (30 °C/36 h/100 rpm) using two different media with milk whey (i) without filtration, pH 6.8, adjusted with NaOH 2 mol L^?1 and without pH adjustment, both autoclaved at 121 °C for 30 min, and (ii) filtrated (1.20 µm and 0.22 µm membrane filter). These cultures were transferred five times using 5 mL aliquots of broth culture for every new volume of the respective media. RESULTS: The results showed that culture media composed of milk whey without filtration supplied L. lactis its adaptation needs better than filtrated milk whey. Nisin titers, in milk whey without filtration (pH adjusted), was 11120.13 mg L^?1 in the second transfer, and up to 1628‐fold higher than the filtrated milk whey, 6.83 mg.L^?1 obtained in the first^t transfer. CONCLUSIONS: Biological processing of milk byproducts (milk whey) can be considered a profitable alternative, generating high‐value bioproducts and contributing to decreasing river disposals by dairy industries. Copyright © 2008 Society of Chemical Industry     

A new ZVS-PWM unity power factor rectifier with reduced conductionlosses

This paper introduces a new single-phase high power factor rectifier, which features regulation by conventional PWM, soft commutation and instantaneous average line current control. Furthermore, thanks to the use of a single converter, instead of the conventional configuration composed of a four-diode front-end rectifier followed by a boost converter, a significant reduction in the conduction losses is achieved. A prototype rated at 1.6 kW, operating at 70 kHz, with an input AC voltage of 220 Vrms and an output voltage of 400 V_DC has been implemented in the laboratory. An efficiency of 97.8 % at 1.6 kW has been measured. Analysis, design, and the control circuitry are also presented in the paper     

Principal axes and surface fitting methods for three-dimensional image registration

We evaluated the effect of the image acquisition parameters on the accuracy of the principal axes and surface-fitting techniques for three-dimensional image registration. Using two types of phantom objects, MR brain image and a mathematically defined ellipsoid, we simulated pairs of scans with known acquisition parameters, including longitudinal coverage, magnitude of mis-registration, number of sections and section thickness. Both methods are sensitive to the systematic deformation of contours. The principal axes method is also sensitive to incomplete scan coverage and to the x-axis and y-axis misangulation. Both methods are insensitive to the number of sections, section thickness and the number of points per section. Surface fitting performed well without user supervision. There is no need for routine inclusion of the scaling factors as search parameters. The results confirm the feasibility of three-dimensional multimodality registration of brain scans with accuracy 1-2 mm, with surface fitting being the method of choice.