Nonlinear thermal analysis of multi-holed lightweight concrete blocks used in external and non-habitable floors by FEM

The aim of this current and innovative work is the numerical thermal analysis of multi-holed lightweight concrete blocks for external and non-habitable floors by the finite element method (FEM). Twelve different block designs with the same external dimensions 0.57 × 0.45 × 0.20 m were built varying the number of the horizontal intermediate bulkheads, from 3 to 12. Besides, five different compositions of the lightweight aggregate concrete (LWAC) and five different bulk temperatures have been taken into account, giving place to a total of 600 different floor configurations, 300 cases per each heat flow direction: upward and downward heat flows. A nonlinear thermal problem is solved for all cases analysed and then, it is possible to choose the best candidate block from the standard rule requirements. Mathematically, the nonlinearity due to the radiation boundary condition inside the inner recesses of the blocks is tackled by the matrix radiation method. Once the nonlinear thermal problem is solved, the temperature distribution is obtained and the thermal characteristic values of the floors, both for downward and upward heat flows, are calculated. From the numerical results, we can conclude that the main variables in the thermal performance are the total number of recesses and the material conductivities. Therefore, increasing the number of horizontal intermediate bulkheads and decreasing the material conductivities, the best thermal efficiency is obtained. The selection of the best candidate block of external floors and floors in contact with non-habitable spaces is carried out through the following parameters: the average mass overall thermal efficiency and the equivalent thermal conductivity. Finally, detailed instructions are provided in order to select the appropriate floor satisfying the standard rule requirements and conclusions of this work are exposed.     

Physicochemical characterisation of raw fish and stickwater from fish meal production

Chemical and microbiological properties of raw fish (RF) and chemical properties of stickwater (SW) samples were studied as a function of the staleness level of the fish. As time elapsed from fish capture increased, the microbial count in RF, volatile nitrogen content in RF and SW, and dissolved solids and dissolved protein in SW, increased. The apparent viscosity of SW increased as the temperature decreased and as the dry solids or suspended matter content increased. The size distribution of suspended particles in SW depended on the sample preparation technique, method used to measure particle size and whether the size distribution was expressed in terms of the weight or population of fractions. The average size (by weight) of suspended solids in SW was 2.5 μm as estimated by electronic counting. The solubility of protein in SW decreased when acid or alkali were added or thermal treatment (1 h at 90°C) applied. A minimal solubility point occurred near pH 5. The molecular weight of most dissolved proteins in SF was 3 kD. SF also contained a small proportion of 67 kD proteins. The significance of this basic characterisation study for the selection of improved processes for stickwater recovery is discussed.     

COMPUTATION OF HEAT AND FLUID FLOW IN DUCTS OF ARBITRARY CROSS SECTION

This paper reports on connective heat transfer in irregular ducts maintained under a constant wall temperature. In particular, due to the complexity of the geometry, the paper investigates in detail the fluid flow and convective heat transfer in right-triangular and semicircular ducts. The hydrodynamically fully developed flow and the developing temperature in these geometries are obtained analytically/numerically from the solution of the energy equation employing the method of lines. The energy equation is reformulated by a system of a first-order differential equation controlling the temperature along each line. It was found that reliable closed-form solutions for the temperature distribution in the thermal entrance region can be obtained utilizing 21 lines, or less, displayed in the cross-stream direction of the duct. The grid pattern chosen provides: drastic savings in computing time. Results for the thermal entry region flow heat transfer are presented in tabular and graphical forms. The representative curves illustrating the variation of bulk temperature and Nusselt numbers with pertinent parameters in the entire thermal entry region are plotted. The computed results are compared against some analytical/numerical findings reported in the literature. In all cases, satisfactory comparison is obtained. The asymptotic Nusselt numbers are 1.90, 2.25, and 2.29 for 15°, 30°, and 45° right-triangular ducts, respectively, and 6.030 for semicircular ducts     

Content of free phenolic compounds in bananas from Tenerife (Canary Islands) and Ecuador

Determination of free gallic acid and catechin (cianidanol) in banana samples was optimized using a high-performance liquid chromatographic (HPLC) method with on-line photodiode array detection. This method was applied for cultivars of bananas (Gran Enana and Pequeña Enana) harvested in Tenerife (Canary Islands) and for bananas (Gran Enana) from Ecuador. The contents of catechin and gallic acid in bananas from Ecuador were higher (P<0.05) and lower than in bananas produced in Tenerife. Variations in the contents of these polyphenolic compounds in the bananas from Tenerife according to cultivation method (greenhouse and outdoors), farming style (conventional and organic) and region of production (north and south) were observed.     

Occurrence of salmonellae in retail chicken carcasses and their products in Spain

This study examined the incidence of Salmonella in Spanish poultry products. Samples included chicken carcasses, chicken parts (wings, legs and giblets-livers and hearts) and processed chicken products (red sausages, white sausages and hamburgers). The average detection rate was 49%, with the highest (55%) in chicken carcasses (skin) and the lowest (20%) in hamburgers. The chicken carcasses purchased in supermarkets were more contaminated (75%) than those from poulterers shops (25%). Salmonella Enteritidis, S. Poona, S. Paratyphi B and S. Worthington were isolated in 34.3%, 11.4%, 2.8% and 1.4% of the samples, respectively. One (1.4%) red sausage sample harboured two serotypes (S. Enteritidis and S. Worthington). This fact emphasizes the usefulness of subtyping several Salmonella isolates from the same sample in epidemiological studies.     

Study of pressure and temperature developing profiles in crude oil pipe flows

Pressure and temperature developing profiles for crude oil transportation pipelines are simulated under a diversity of external boundary conditions. MOLCV is used in this research to convert a system of partial differential equations into a system of ordinary first order differential equations in cylindrical coordinates. Momentum and energy balance equations are coupled in crude oil flows because of thermal–physical property variations. Simulation solutions show the effect of boundary conditions in the pressure drop profile, which provide potential model predictive applications to account for weather forecast in crude oil transportation operations.     

Effect of Crude Oil Composition and Blending on Flowing Properties

The effect of crude oil n-paraffin molecular weight distribution on wax crystallization risk was studied. Sixteen highly paraffinic crude oils from Eastern Venezuela were characterized, in terms of hydrocarbon family distribution, by High Temperature Simulate Distillation (HTSD), Gel Permeation Chromatography (GPC), and wax content. n-Paraffin chain length was correlated with crude oil cloud point and pour point. It was demonstrated that high molecular weight linear paraffins are responsible for crude oil wax precipitation. A quantitative correlation between molecular weight distribution and crude oil flowing properties was also obtained. It was found that the wider the molecular weight distribution, the lower is the wax crystallization risk. Blends of different paraffinic crude oils were prepared and their flowing properties were evaluated in comparison with the original crudes. Cloud points below the mean value were obtained. In some cases, a synergistic effect was observed (cloud points below the minimum of the two crude oils). Blends of some of these crudes with condensates afforded improvements on crude oil flow and a reduction of wax crystallization tendency (cloud point). This phenomenon can be attributed to a combination of two factors: I. increases in C24-n-paraffins, and II. a wider molecular weight distribution.     

Method for analyzing series resistance and diode quality factors from field data of photovoltaic modules

A procedure is detailed in which the effects of series resistance and diode quality factors are separately analyzed and quantified using current–voltage (IV) data gathered in situ from three photovoltaic (PV) modules. Series resistance losses are implicated to be largely responsible for reduction in the fill factor values for intensities of 60% of one sun or greater. The data presented are from one cadmium telluride (CdTe) and two amorphous silicon (a-Si) modules and were taken in field deployment with a data acquisition system.     

Damage tolerance investigations on rails

The paper summarises damage tolerance investigations on railway rails which the authors have carried out in the context of the German-French joint project NOVUM (novel methods for quantitative prediction of rail performance at increased service loads) [Girardi L, Heyder R, Dider L, Boulanger D. IDR2-NOVUM promises lower rail maintenance costs. Railway Gazette Int 2005;(July):439-41[1]]. The investigations include the determination of the crack driving force as a function of the various loading components a rail is subjected to and the simulation of residual lifetime. Features such as the local load input at the rail-wheel interface, dynamic effects and statistical aspects of crack resistance are explicitly taken into account.     

La CLAve to increase psychosis literacy of Spanish-speaking community residents and family caregivers.

The authors developed and tested a 35-min psychoeducational program with the goal of increasing Spanish-speaking persons’ literacy of psychosis. The program uses popular cultural icons derived from music, art, and videos, as well as a mnemonic device—La CLAve (The Clue)—to increase (a) knowledge of psychosis, (b) efficacy beliefs that one can identify psychosis in others, (c) attributions to mental illness, and (d) professional help-seeking. Assessments were conducted before and after administering the program to both community residents (n = 57) and family caregivers of persons with schizophrenia (n = 38). For community residents, the authors observed increases across the 4 domains of symptom knowledge, efficacy beliefs, illness attributions, and recommended help-seeking. For caregivers, increases were observed in symptom knowledge and efficacy beliefs. La CLAve is a conceptually informed psychoeducational tool with a developing empirical base aimed at helping Spanish-speaking Latinos with serious mental illness obtain care in a timely manner. (PsycINFO Database Record (c) 2010 APA, all rights reserved)