Single-Particle Analysis in An Indoor Working Environment in Valencia, Spain

Actually is recognized the importance of indoor air environment and associated health risks. In order to evaluate indoor air quality and to characterize the particles in terms of size, composition and shape were done measurements of the suspended particulate matter in a mechanical workshop of the Polytechnic University of Valencia (Spain). These measurements were performed using scanning electron microscope (SEM) with energy dispersive X-ray microanalysis (EDX) and image digital analysis. To differentiation of individual particles in the fine- ultrafine fraction, in some case, was used the atomic force microscopy (AFM). Multivariate statistics, such as hierarchical cluster analysis and factor analysis were appliqued and allowed to establish groups of elements and in this way to facilitate the identification of the natural and anthropogenic sources. It is confirmed that indoor air is influenced by outdoor surroundings and the anthropogenic sources due to the daily activity.

HERMITE MATRIX POLYNOMIALS AND SECOND ORDER MATRIX DIFFERENTIAL EQUATIONS

In this paper we introduce the class of Hermite's matrix polynomials which appear as finite series solutions of second order matrix differential equations Y'-xAY'+BY=0.An explicit expression for the Hermite matrix polynomials,the orthogonality property and a Rodrigues' formula are given.

Reassessment of Prejanopterus curvirostris, a Basal Pterodactyloid Pterosaur from the Early Cretaceous of Spain

Prejanopterus curvirostra, from the Early Cretaceous of La Rioja province, was the first pterosaur genus and species described from Spain. The material comprises disarticulated cranial and postcranial remains from several individuals. The fossil-bearing bed is assigned to the lacustrine Leza Formation （eastern Cameros Basin, NW margin of the Iberian Range）. This unit is regarded as either Berriasian-Valanginian or Barremian-Aptian. Prejanopterus curvirostris （specific name emended） was originally diagnosed on the basis of several characters of which the most significant was a lateral curvature of the rostrum. Re-examination of the holotype （rostrum） and paratype （partial rostrum with teeth） indicates that there is no genuine sideways bend of the preserved premaxilla-maxilla segments, but a slight dorsal curvature. Prejanopterus is characterized by a unique combination of characters： an emended diagnosis is provided. In contrast with previous estimates, the wing span of Prejanopterus was probably not much （if ever） in excess of 2 m. A phylogenetic analysis suggests that Prejanopterus is a basal pterodactyloid positioned between Pterodactylus and Cycnorhamphus- Gallodactylus. Prejanopterus represents the first evidence of Pterodactylidae in the Early Cretaceous of the Iberian Peninsula.

Application of Statistical Methods to Assess Carbon Monoxide Pollution Variations within an Urban Area

In recent years there have been considerable new legislation and efforts by vehicle manufactures aimed at reducing pollutant emission to improve air quality in urban areas. Carbon monoxide is a major pollutant in urban areas, and in this study we analyze monthly carbon monoxide (CO) data from Valencia City, a representative Mediterranean city in terms of its structure and climatology. Temporal and spatial trends in pollution were recorded from a monitoring net- work that consisted of five monitoring sites. A multiple linear model, incorporating meteorological parameters, annual cycles, and random error due to serial correlation, was used to estimate the temporal changes in pollution. An analysis performed on the meteorologically adjusted data reveals a significant decreasing trend in CO concentrations and an annual seasonal cycle. The model parameters are estimated by applying the least-squares method. The standard error of the parameters is determined while taking into account the serial correlation in the residuals. The decreasing trend im- plies to a certain extent an improvement in the air quality of the study area. The seasonal cycle shows variations that are mainly associated with traffic and meteorological patterns. Analysis of the stochastic spatial component shows that most of the intersite covariances can be analyzed using an exponential variogram model.

线型和非线型分子转动光谱强度的统计模型(英文)

In this study, we found regular behavior, from a statistical point of view, in the intensities of rotational spectra for several organic and inorganic molecules at room temperature. Non-linear molecules, for which a common intensity behavior was derived, were especially interesting. We provided theoretical support for the obtained results based on the Boltzmann distribution. Boltzmann power laws were used to reproduce the statistical behavior of the intensities from the spectra of linear and non-linear molecules. We only used statistical arguments and no specific details of any molecule were used. Therefore, these results are applicable to a large class of atoms and molecules and the model is valid when considering similar conditions to those used in this study.

Some additive results on Drazin inverse

In this paper, we investigate additive results of the Drazin inverse of elements in a ring R. Under the condition ab = ha, we show that a ＋ b is Drazin invertible if and only if aaD （a ＋ b） is Drazin invertible, where the superscript D means the Drazin inverse. Furthermore we find an expression of （a ＋ b）D. As an application we give some new representations for the Drazin inverse of a 2 × 2 block matrix.

Heat Production Partition in Sheep Fed above Maintenance from Indirect Calorimetry Data

The objective of this study is to compare the partition of heat energy (HE) in two sheep breeds by indirect calorimetry and integral calculus. An experiment was conducted with two Spanish native sheep breeds (dry and non-pregnant) which were fed with pelleted mixed diets above maintenance. Six Guirras and six Manchegas breed sheep were selected (58.8 ± 3.1 and 60.2 ± 3.2 kg body weight, respectively). All sheep were fed with the same concentrate mixed ration (0.300 kg cereal straw as forage and 0.700 kg concentrate) in two meals. Half the daily ration was offered at 800 h and another half at 1600 h. The sheep had free access to water. Sheep were allocated in metabolic cages;energy balance and gas exchange were assessed in each sheep. The statistical analyses included the fixed effect of breed and random effect of sheep. The metabolic energy (ME) for maintenance represented 69% of the total ME intake and the average was 354 kJ per kg of metabolic body weight (kg0.75 BW) on average. The basal metabolism (HeE) was greater (P < 0.05) in Guirra than Manchega breed (270 ± 18 vs. 247 ± 15 kJ/kg0.75 BW and day). As sheep were fed with above maintenance, the retained energy in the body accounted for 22% of the ME intake and 77% of the ME intake was lost as heat. 51% of the MEI was converted to HeE;5% was lost as physical activity of standing and lying down (HjE), and 13% was associated with the process of feeding and work of digestion and metabolism (HdE). Within HdE, 47% represented the cost of intake and feeding and 54% the cost of digestion and metabolism. No differences in HE partition between breeds were found, although Guirra breed showed less efficiency of energy retention than Manchega breed. Therefore, this study demonstrated a tentative approach of partitioning HE, combining indirect calorimetry and integral calculus.

Environmental Impacts (ER CO₂) of an Improved Multi-Fuel Gasifier Forced Air Cookstove in the City of Kinshasa

Sub-Saharan African countries depend 80% on the biomass-wood to meet their daily needs in terms of cooking foods. Traditional cookstoves are much more used to this effect. Many change programmes for replacing cookstove model have been planned. Yet many of these programmes have not been preceded by environmental impact studies. This work offers high-performance cookstove models and determines their impact on the reduction of CO2 emissions, a very harmful greenhouse gas causing the planet warming and climate change. Replacing the traditional cookstove by an improved stove may lead to an economy in terms of fuel ranging from 33.2% to 75.4% according to the model of cookstoves. Yet the Gasifier using pellets as fuel remains the most beneficial stove in terms of fuel saving (75.4%) and in terms of ER CO2, i.e. 2748 t CO2/Year. An improved gasifier cookstove is multi-fuel. He can use charcoal, pellets and wood. This is an indispensable cooking tool with alternative fuels. In this work, the ER CO2 was evaluated using two methods. The KPT, which is a field method and the CCT which is a laboratory method. By the KPT method a gasifier ICS/GAS/P records up to an ERCO2 of 2748 t CO2/Year, while with the same gasifier, an ERCO2 of 2619 t CO2/year is found by the CCT method. The comparison between the two methods shows the same trend but with very high values of ERCO2 for the KPT method results. The variation between the two methods ranges between 1% approximately to 6.9 percent.

Modeling Multiple Quantum Well and Superlattice Solar Cells

The inability of a single-gap solar cell to absorb energies less than the band-gap energy is one of the intrinsic loss mechanisms which limit the conversion efficiency in photovoltaic devices. New approaches to “ultra-high” efficiency solar cells include devices such as multiple quantum wells (QW) and superlattices (SL) systems in the intrinsic region of a p-i-n cell of wider band-gap energy (barrier or host) semiconductor. These configurations are intended to extend the absorption band beyond the single gap host cell semiconductor. A theoretical model has been developed to study the performance of the strain-balanced GaAsP/InGaAs/GaAs MQWSC, and GaAs/GaInNAs MQWSC or SLSC. Our results show that conversion efficiencies can be reached which have never been obtained before for a single-junction solar cell.

Ostrowski’s Method for Solving Nonlinear Equations and Systems

The dynamic characteristics and the efficiency of the Ostrowski’s method allow it to be crowned as an excellent tool for solving nonlinear problems.This article shows different versions of the classic method that allow it to be applied to a wide range of engineering problems.Among them stands out the derivative-free definition applying divided differences,the introduction of memory and its extension to the resolution of nonlinear systems of equations.All of these versions are compared in a numerical simulations section where the results obtained are compared with other classic methods.