[en] The iron and steel industry, which accounts for between two and three percent of all energy consumed in this country, is also striving to improve its energy efficiency. The amount of energy required to produce a ton of steel has decreased by more than 40% since 1975. This reduction has been accomplished in part through adoption of more energy-efficient and productive processing steps. However, the capital to invest in new technologies is increasingly limited, especially as the costs of environmental control continue to rise. Other than foreign competition, the biggest challenge facing the industry today is compliance with environmental regulations. The Clean Air Act and the Resource Conservation and Recovery Act have had significant impacts on the industry. Since 1970, the industry has invested approximately $6 billion in pollution control systems. The industry spent approximately $230 million in both 1993 and 1994 on capital expenditures for pollution abatement. In a typical year, 15% of the industry's capital investments go to environmental projects. The industry faces even more challenges in the future as new, more stringent regulations are enacted. Topics covered here are: market trends and statistics; energy and materials consumption; and an environmental overview

[en] After outlining the space and time discretization methods used in the N3S thermal hydraulic code developed at EDF/NHL, we describe the possibilities of the peripheral version, the Adaptative Mesh, which comprises two separate parts: the error indicator computation and the development of a module subdividing elements usable by the solid dynamics code ASTER and the electromagnetism code TRIFOU also developed by R and DD. The error indicators implemented in N3S are described. They consist of a projection indicator quantifying the space error in laminar or turbulent flow calculations and a Navier-Stokes residue indicator calculated on each element. The method for subdivision of triangles into four sub-triangles and tetrahedra into eight sub-tetrahedra is then presented with its advantages and drawbacks. It is illustrated by examples showing the efficiency of the module. The last concerns the 2 D case of flow behind a backward-facing step. (authors). 9 refs., 5 figs., 1 tab

[en] This paper deals with the introduction of a second moment closure turbulence model (Reynolds Stress Model) in an industrial finite element code, N3S, developed at Electricite de France.The numerical implementation of the model in N3S will be detailed in 2D and 3D. Some details are given concerning finite element computations and solvers. Then, some results will be given, including a comparison between standard k-ε model, R.S.M. model and experimental data for some test case. (authors). 22 refs., 3 figs

[en] Alternative technologies must be developed and implemented considering sanitation and preservation of eggs mainly for risk population. Food irradiation is an alternative to free Salmonella spp. and Campylobacter spp. eggs, as a low dose point to a safety assurance. This study presents the correlation between irradiation doses (0.5 kGy up to 5 kGy at dose rate of 1.0 kGy/h) and some of functional and nutritional egg properties. Viscosimetry of non-irradiated and irradiated eggs was evaluated by means of VT550 Haake with an NV sensor and co-axes cylinders. After irradiation at 5 kGy, the yolk colour die (pale yellow) and the white egg was modified to a turbid yellow. The Cross equation was utilized to viscosimetry curves. Based on the assymptotics viscosimetry data indicated that increase of doses corresponds to an increase of the yolk and a decrease of white egg viscosimetry as such a Newton behaviour. Irradiation effects on nutritional properties were evaluated by means of egg protein patterns that were assessed by polyacrylamide gel electrophoresis. Lipids were identified by TLC. Based on results the sanitation dose is lower than the limit dose for the decrease of the main eggs properties

[en] The specific heat (c_p) of the dilute antiferromagnet Fe_xZn_1-xF₂ has been measured in absence of external magnetic fields for x = 0, 0.26, 0.31, 0.34, 0.36, 0.38, 0.41, 0.45, 0.56, 0.88, 0.97, and 1.0. For x > 0.45, a sharp peak associated to the antiferromagnetic (AF) phase transition at T_N(x) is the only observed feature. For 0.31 ≤ x ≤ 0.41, this peak becomes smaller with decreasing x and a rounded bump appears at higher temperatures T. Closer to the percolation concentration (x_p = 0.24), the peak characteristic of the AF phase transition disappears and the rounded bump becomes the only observed feature. The low-T c_p behavior confirms a crossover from AF long range order at large x to a spin glass behavior close to x_p. At intermediate x, the low-T joint signature of both phenomena indicates a coexistence of AF order and a cluster-glass phase. The x-dependence of the Neel temperature was accounted for using a simple phenomenological model.

[en] The Press-Ryden-Spergel (PRS) algorithm is a modification to the field theory equations of motion, parametrized by two parameters (α and β), implemented in numerical simulations of cosmological domain wall networks, in order to ensure a fixed comoving resolution. In this paper we explicitly demonstrate that the PRS algorithm provides the correct domain wall dynamics in (N+1)-dimensional Friedmann-Robertson-Walker universes if α+β/2=N, fully validating its use in numerical studies of cosmic domain evolution. We further show that this result is valid for generic thin featureless domain walls, independently of the Lagrangian of the model.

[en] We develop a velocity-dependent one-scale model describing p-brane dynamics in flat homogeneous and isotropic backgrounds in a unified framework. We find the corresponding scaling laws in frictionless and friction-dominated regimes considering both expanding and collapsing phases.

[en] The thermo-catalytic degradation of polyethylene (PE) and ultra-high molecular weight polyethylene (UHMWPE) was studied in the presence of zeolites (ZSM-5, ZSM-22, and ferrierite) with different pore systems and textural properties. The zeolites were physically mixed with polymers in the proportion of 30 wt% and submitted to thermogravimetric analysis at heating rates of 5, 10, 20, and 30 °C.min^-1. The activation energy of the degradation process was determined using the Flynn-Wall-Ozawa method. The addition of zeolites to polymers has considerably reduced the temperature of degradation. ZSM-22 demonstrated greater efficiency in the degradation of PE because it has a smaller crystallite size, promoting a shorter diffusional path for the polymer fragments coming from the surface. Ferrierite showed a lower energy level in the degradation of UHMWPE, showing the need for synergy between the accessibility of the structure and acidity of the catalyst to promote the cracking of this polymer. (author)

[en] Infusion medical devices are used in field applications, namely in clinical environments, here are used several types of liquids, according to the therapeutic to be administrated into the patient. In order to determine the influence of the fluids physical properties, such as viscosity and density and to produce an adequate reference liquid, tests were performed with a syringe pump, using the gravimetric method as reference calibration method

[en] Morphological and functional state of hepatopancreas were analyzed in Palaemonetes argentinus from two environments with different pesticide concentrations. Los Padres lagoon (Argentina) is an area subjected to contamination due to the slow exchange of water, the shallow depth and the input of contaminated water. Prawns living in this lagoon accumulate high amounts of organochlorine pesticides in their tissues. Hepatopancreas of prawns from Canal 5, an adjacent shallow stream where the amount of pesticides is below toxic levels, and from Los Padres lagoon were processed by standard histological techniques with light microscopy and transmission electronic microscopy. At Los Padres lagoon, there were found important tissular alterations, such as intertubular infiltration of haemocytes and connective tissue, epithelial retraction in some tubules, and a folded basal lamina. Important necrotic desquamation, with cariolysis, cariorrexis and lack of cellular details were also observed. Numerous tubules presented an enlarged and irregular lumen with the epithelium atrophied or completely absent. In general, the lesions were particularly located in the medullar region of the organ. At the ultrastructural level, R and F cells were the most damaged. Both cell types had nuclear retraction, chromatin condensation and cytoplasmic lysis. Some R cells also had dilated mitochondria and numerous lysosomes, and the basal cytoplasm was nearly completely lysed. The hepatopancreas of prawns from Canal 5 did not evidence any alterations. The histopathological study of the hepatopancreas is a highly sensitive tool to evaluate the physiological condition of prawns and water quality. Other environmental conditions were similar, so it can be assumed that pollutants were the main cause of organ deterioration. (author)