In-situ density estimation by four nondestructive techniques on Norway spruce from built-in wood structures

Needle penetration resistance (NPR), screw withdrawal resistance (SWR), core drilling (CD) and drilling chips extraction (DCE) are nondestructive and semi-destructive techniques used to estimate density in timber structures. In most of the previous studies, these techniques were tested in clear sawn timber and clear specimens. The goal of the present paper is to study the relationship between density and these techniques by means of five different devices in whole pieces of timber from built-in engineering structures, which are from 12 4.5-m long structural timber joists of Norway spruce from a 19th century building in Barcelona (Catalonia, Spain). Although determination coefficients (R2) for density estimation models were lower than those from clear timber, the results obtained confirmed that these four techniques are suitable for in-situ density estimation of woods in buildings. The best results were obtained by CD (the bigger the bit, the higher the correlation), followed by DCE, and SWR. The worst correlation was found for NPR devices, but the results could be probably improved with more measurements.Peer ReviewedPostprint (published version

Determination of the mechanical properties of corn grains and olive fruits required in DEM simulations

Discrete element method (DEM) is a numerical technique widely used for simulating the mechanical behavior of granular materials involved in many food and agricultural industry processes. Additionally, this technique is also a powerful tool to understand many complex phenomena related to the mechanics of granular materials. However, to make use of the potential of this technique it is necessary to develop DEM models capable of representing accurately the reality. For that, among some other questions, it is essential that the values of the microscopic material properties used to define the numerical model are accurately determined

Determinación del coeficiente de rozamiento grano-pared en silos de pared corrugada mediante el método de los elementos discretos

El comportamiento de los materiales granulares almacenados en silos se ve afectado por varios parámetros, tanto aquellos característicos del material como de la geometría del silo. La determinación del coeficiente de rozamiento pared-partícula es uno de los parámetros de mayor importancia, siendo habituales en su determinación el uso de ensayos de corte directo. En el presente trabajo se estudia dicho coeficiente para el supuesto de una pared corrugada, el cual, teóricamente, debe representar a un valor efectivo que depende tanto del coeficiente de rozamiento grano-pared (para el caso de una pared lisa) y el ángulo de rozamiento interno del material. La determinación del rozamiento efectivo se ha realizado a través de la simulación por elementos discretos de un ensayo de corte sobre una pared corrugada. Los valores obtenidos han sido comparados con las prescripciones expuestas en la normativa vigente. La potencialidad del método de los elementos discretos permite el estudio de diversas configuraciones geométricas de la pared corrugada de los silos sin necesidad de realizar ensayos de laboratorio. Esto permitirá, en trabajos sucesivos, investigar la influencia de muy diversos factores en el valor del rozamiento efectivo grano-pared en este tipo de paredes. The mechanical behaviour of granular materials stored in silos is affected by numerous parameters, some of them being related to the characteristic of the stored materials and others to the geometry of the silo. The determination of the particle-wall friction coefficient (or wall friction) is of great importance and direct shear tests are usually conducted in order to obtain its value. In this work this variable is analysed for the case of a corrugated wall. This value is expected to be an effective value between the particle-wall friction coefficient (obtained for a flat wall) and the internal friction coefficient of the material under study. The effective wall friction determination has been carried out by using a discrete element model to simulate a direct shear test on a corrugated wall. The values obtained have been compared with prescriptions given in the current standards. The potential of the discrete element method allows different geometries of the silo corrugated wall to be considered without the necessity of developing laboratory tests. In future works it will allow the influence of numerous parameters on the effective wall friction in corrugated walls to be studied

The effect of moisture content on nondestructive probing measurements

When assessing existing timber structures it is not possible to obtain density as the ratio mass/volume, so nondestructive probing methods are used to predict density. As in other nondestructive techniques, moisture content influences measurements. The goal of this paper is to study the influence of timber moisture content on two nondestructive probing techniques (penetration resistance and pullout resistance). 25 large cross section specimens of laricio pine from Spain were measured. The moisture content ranged from 65.1% to 8.3%. Penetration depth decreases and screw withdrawal strength increases when moisture content decreases below the fiber saturation point. There are lineal tendencies in both techniques. No moisture content influence was found in measures above fiber saturation point

Influence of temperature and moisture content in Non-destructive values of Scots pine (Pinus sylvestris L.)

Good results evaluating material properties using non-destructive testing (NDT) techniques have been achieved for decades. Several studies to understand the influence of temperature and moisture content on NDT have concluded different effects. In this study, NDT parameters were measured on the principal structural Spanish sawn timber species, Scots pine (Pinus sylvestris L.). NDT were conducted on 216 specimens of nominal dimensions 20 by 20 by 400 mm. Specimens were divided into several groups and studied at six different temperatures and four different moisture contents. Commercial equipment and techniques applied were Sylvatest Duo (ultrasonic wave technique), Steinkamp BPV (ultrasonic wave technique), and Grindo Sonic Mk5 "Industrial" (vibration analysis technique). Differences in NDT values within specimens at different temperatures and moisture contents were obtained. Main results of this study and relationships that describe changes in NDT values by effect of temperature and moisture content are presented

Radon concentration in caves as a proxy for tectonic activity in the cantabrian mountains (Spain)

Radon (Rn) constitutes a good geochemical tracer for neotectonic activity in faults since associated fracturing near the surface favours fluid escape to the atmosphere. In this contribution, we measured the Rn concentration in the air inside karst caves to constraints the recent fault activity in the Cantabrian Mountains (N Spain). Rock formations exhumed during the uplifting of the Cantabrian Mountains record a long history of fracturing, which has the potential to connect deeper sources of Rn with the surface. In this regional study, we correlate Rn measurements with cave survey data and geological structures using a Geographic Information Systems. Thirty-four Rn average concentration was recorded by CR-39 detectors during 8 integrated months. The method is applied to the central part of the Cantabrian Mountains that is built on sedimentary and low-grade metamorphic rocks relatively poor in U. Dominant tectonic structures and Rn concentration are examined in 28 cavities. The concentration of Rn values is higher than 0.5 kBq·m-3 in caves developed preferably following fractures with the direction N30oW, being the concentration greater than 0.8 kBq·m-3 in cavities located less than 200±50 m from subvertical faults with such orientation. Rn anomalies point to relative high connectivity along subvertical fault zones NW-trending, preserving fracture connectivity in the most recent structures in the Cantabrian Mountains. Finally, in the study area there is a low but significant radioactive hazard which is associated to fault zones in a fractured rock massif. It contrasts with other active tectonic settings where the radioactive hazard may come from fault movements

In vitro study of the viability of Caco-2 cells in presence of two compound of Allium spp essential oil

El aceite esencial de los componentes del género Allium, principalmente ajo y cebolla, presenta propiedades antioxidantes y antibacterianas debidas a la presencia de compuestos azufrados en su composición. La industria alimentaria ha comenzado a desarrollar nuevos sistemas de envasado activo a partir de polímeros seleccionados, a los que se incorporan aceites esenciales que, por sus propiedades, contribuyen a aumentar la vida útil de los alimentos perecederos. En este sentido, se hace necesario evaluar la seguridad asociada al uso de estas sustancias en envases alimentarios que van a estar en contacto con el consumidor a través del alimento. El objetivo del presente estudio fue determinar la citotoxicidad producida por dipropil sulfuro y dipropil disulfuro, dos de los componentes del aceite esencial de ajo y cebolla, en la línea celular Caco-2, células humanas procedentes de carcinoma de colon. Los biomarcadores ensayados fueron el contenido total de proteínas, la captación de rojo neutro y la reducción de la sal de tetrazolio (3-(4,5-dimetiltiazol-2- il)-5-(3-carboximetoxifenil)-2-(4sulfofenil)-2H-tetrazolio). Las células fueron expuestas durante 2, 4 y 8 h a concentraciones comprendidas entre 0 y 200 μM. Los resultados no mostraron diferencias significativas frente al control para ninguno de los tres marcadores, lo que demuestra que bajo las condiciones de los ensayos ambos compuestos azufrados no son citotóxicos para esta línea celular gastrointestinal y podrían ser útiles en la industria alimentaria para desarrollar envases activos.Allium spp. essential oil, mainly from garlic and onion, possesses different beneficial properties, for example antioxidant and antimicrobial effects, due to the presence of sulfur compounds. Food industry is developing new active packaging systems that include the essential oil of garlic in their structure, in order to improve the shelf-life of perishable products. Therefore it is necessary to evaluate the safety associated with the use of these substances in food packaging that will be in contact with the consumer through food. The aim of our study was to evaluate in vitro the cytotoxicity of dipropyl sulfide and dipropyl disulfide. For this purpose, we used the human Caco-2 cell line, from human small intestinal mucosa carcinoma. The assayed cytotoxicity biomarkers were the total protein content, neutral red uptake and reduction of the 3-( 4, 5 - dimethylthiazol - 2 - y l ) - 5 - ( 3 - carboximethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium salt. Cells were exposed to dipropyl sulfide and dipropyl disulfide in concentrations between 0-200 μM for 2, 4 and 8 h. After periods of exposure, no alterations were observed in any of the biomarkers assayed. These results suggest that both organosulfur compounds are safety options for food industry and could be a choice in the development of active packaging.Ministerio de Ciencia e Innovación (España) AGL2012-38357-C02-01Junta de Andalucía AGR-7252Servicio de Biología del Centro de Investigación, Tecnología e Innovación de la Universidad de Sevilla (CITIUS

Estudio de la citotoxicidad basal de compuestos antioxidantes presentes en el aceite esencial de orégano: CARVACROL y TIMOL

Ministerio de Ciencia e Innovación AGL2012-38357-C02-01Junta de Andalucía AGR-725

Estrés oxidativo producido por carvacrol y su combinación con timol en la línea celular CACO-2

Ministerio de Ciencia e Innovación AGL2012-38357-C02-01Junta de Andalucía AGR-725

Estudio in vitro de compuestos sulfurados del aceite esencial de ajo para su potencial uso en la industria alimentaria

Ministerio de Ciencia e Innovación AGL2012-38357-C02-0