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An offshore wind farm can be located close to traffic lanes of commercial and passenger ships, which may lead to possible collision. The work presented in this paper aims to understand both the crushing behaviour and the nacelle dynamics of a monopile offshore wind turbine when impacted by a ship. Another objective was to deeply investigate the influence of various parameters like ship impact velocity and location, wind direction, soil stiffness and deformability of the striking ship. First, nonlinear numerical simulations of ship - Offshore Wind Turbine (OWT) collisions have been carried out with a rigid striking ship for a better understanding of the OWT's structural behaviour during collision. Different configurations for the wind turbine's structure have been used in order to highlight the modifications in behaviour induced by changing the soil conditions or the loading scenario. The resulting resistant force and internal energies have been compared as well as the tower top (nacelle) displacements and accelerations. Then, another series of simulations have been performed with a deformable ship in order to investigate the influence of the deformability of the striking ship on the OWT's behaviour. It was shown that a slight variation of the impact velocity can lead to consequences ranging from minor damage of the OWT to collapse. Furthermore, the behaviour of the OWT during collision is highly sensitive to wind loads as it was shown that in some cases the OWT can collapse for an impact velocity of only 3 m/s and, in the worst case, can fall directly on the ship. The results obtained showed that it is important to account for the soil flexibility when performing collision simulations because considering the monopile as being clamped at the base would lead to an overestimation of the plastic deformation of the collided structure. Moreover, when the OWT is collided by a deformable striking ship, the deformations of the OWT are 2 times smaller comparing to the deformations caused by impact with a rigid ship and the structure can withstand collisions without collapsing with an impact velocity up to 6 m/s.

This paper presents a simplified analytical method to evaluate the resistance of a single plating lock gate impacted by a river barge. The approach is based on the assumption that the gate behavior may be divided into two successive phases. At the beginning of the collision, local crushing of some structural elements occurs concomitantly with small overall elastic motion of the entire gate. Then, when the penetration of the barge into the gate becomes important, a global plastic mechanism develops over the entire structure. In addition to the membrane and bending deformations occurring classically in such collisions, the particular flat shape of the striking barge bow leads to shear deformations near the gate edges. For all these deformation modes, closed-form expressions of the gate resistance are derived for both local and global deformation phases by applying the upper-bound method. These analytical developments are then validated through comparisons with numerical solutions obtained from non-linear finite-element simulations.

This paper presents a meshless method to perform the seismic analysis of a plane lock gate. The approach is based on the analytical derivation of the total hydrodynamic pressure, with due consideration for the gate flexibility. In particular, the flexibility of the gate and the fluid–structure interaction are taken into account in the calculation of the equivalent force that has to be applied on the gate to model the action of the water. To reach this goal, the Rayleigh–Ritz method is first used to determine the modal properties of the dry structure. This is achieved by using mode shapes extracted from the beam theory as generating functions. The results obtained in this way are validated by comparison with numerical solutions. The second step consists in performing the dynamic analysis of the gate by deriving a weak form of the equilibrium equation. Based on the Galerkin method, a matrix formulation is derived and the Newmark integration scheme is used for the evaluation of the pressure during the earthquake. Here again, non-linear finite element simulations including water modeling are carried out to corroborate the analytical developments. In addition, the lumped-mass method is also investigated and a criteria is proposed to check its applicability. Finally, some concluding remarks are given to perform more easily the seismic analysis of lock gates.

The aim of this paper is to present a simplified analytical method for estimating the crushing resistance of an oblique cylinder impacted by the stem of a striking ship. The collision angle of the vessel is arbitrary, i.e. oblique collisions are also considered in this article. The two extremities of the tube are assumed to be clamped. These developments are intended to be used for evaluating the crashworthiness of an offshore wind turbines jacket. To achieve this goal, closed-form expressions are first derived for the particular situations of a horizontal and a vertical cylinder by applying the upper-bound method. An interpolation formula is then proposed to get the resistance opposed by the tube for any inclination angle. In order to validate these theoretical developments, some comparisons are made with the results of numerical simulations. These latter are performed using the finite elements software LS-DYNA. In almost all cases, the analytical prediction of the resistance is found to be in quite good agreement with the numerical ones. Finally, another comparison is made by simulating an OSV collision with a full jacket. In this case, the theoretical model is found to be insufficient for large impact energies and points out the need of further research.

This paper provides a new contribution to the simplified analytical treatment of collisions between two ships. It is directly connected to the well-known super-elements method, which is a simplified procedure allowing for a quick estimation of the damages caused to both the striking and struck vessels during such events. In this article, a new analytical formulation is presented for estimating the impact resistance provided by inclined ship side panels. Two different scenarios are treated. We first deal with the case of an impact between the oblique plate and the stem of the striking ship, and then we consider the situation where the inclined panel is impacted by the bulb. For these two scenarios, an analytical formulation relating the force and the penetration is provided and these developments are validated by comparing them to the results of finite elements simulations. Finally, the new inclined plate super-element is integrated in a simplified model of a frigate collided by another ship, and the resistance given by the super-elements method is then compared to the one obtained by a numerical simulation of this collision.

The present article is concerned with the resistance of a ship during a collision with another ship. The paper is directly related to the so called super-elements method developed to estimate the capability of a ship to withstand to an impact. This approach consists of dividing the structure into several elements (the so-called super-elements), whose resistance to collision is evaluated individually. At the recent stage of development, the super-elements method is only able to treat the case of perpendicular collision scenarios. The purpose of this paper is to go one step further, by establishing analytical formulations giving the resistance of various super-elements to an oblique impact.As a first step, the paper gives a short description of the original super-elements method. After that, analytical calculations in oblique collision cases are performed for the different super-elements involved in the procedure. Finally, the formulations are validated by comparison with results provided by classical nonlinear finite element method. As a conclusion, some perspectives on the future work are presented.

The objective of this study was to validate near-infrared reflectance spectroscopy (NIRS) applied to faeces (FNIRS) for estimating the grass in vivo organic matter digestibility (G-OMD) and the grass dry matter intake (G-DMI, kg/d) of concentrate-supplemented grazing dairy cows. The G-OMD estimates from one FNIRS model were compared with two estimates using faecal nitrogen indicator (FNI) methods. Similarly, two FNIRS models were compared with the ratio technique (RT) and with three animal performance methods (APM) for estimating G-DMI. The results were analysed at cow and herd level in two grazed paddocks (P1 and P2) in a rotational grazing scheme. For both G-OMD and G-DMI, the FNIRS estimations were correlated (P r = 0.61 for G-OMD and r = 0.63–0.88 for G-DMI). Depending on the estimation method, the G-OMD varied from 0.689 (FNIRS) to 0.773 (FNI). The FNI estimates were generally higher and were similar to the G-OMD estimates obtained from NIRS analyses of grass sampled in the field. The FNIRS and FNI estimates were biased at cow and paddock level by 0.01–0.1 digestibility units (P Depending on the estimation method, the G-DMI estimates varied from 11.9 to 16.4 kg/d. FNIRS and APM produced similar estimates of G-DMI at both cow and herd level. The RT estimates of G-DMI were 3 kg/d higher than the FNIRS and APM estimates (P For both G-OMD and G-DMI and for all the estimation methods, inter-cow and intra-paddock variations, expressed through the coefficient of variation (SD/mean), ranged from 0.05 to 0.40. As the accuracy of the FNIRS models, expressed through the standard error of cross validation (SECV), was lower than these inter-animal and intra-paddock variations, we suggest that FNIRS could be used to record, quickly and easily, the evolution of grass digestibility and the intake of grazing dairy cows. These estimates could be implemented through decision-support systems aimed at improving the management of grazing dairy herds.

Aquatic ferns (AFs) such as Azolla filiculoides and Salvinia molesta are grown on swine lagoons in the tropics and used in diets for pigs. The present work is aimed at evaluating their potential as feed ingredients for sows. When presented with ad libitum AFs, gilts weighing 110 ± 14 kg (mean ± SD), were able to ingest 9.1–9.7 kg fresh AF per day (from 597 to 630 g dry matter (DM) per day) and from 1240 to 1428 g DM per day when presented in a dry, ground form. A digestibility study was conducted, using sows weighing 213 ± 9 kg (mean ± SD), which were fed diets containing maize, soybean meal and 0, 150 or 300 g AF kg−1 diet. The presence of AFs had a negative impact on the faecal digestibility of the crude protein, NDF and energy content of the whole diet (P 0.05) but increased the weight of the rest of the gastrointestinal tract (P

Aquatic ferns (AFs) such as Azolla filiculoides and Salvinia molesta are grown on swine lagoons in the tropics and used to feed pigs. The present work aimed to determine their nutritional value. Azolla samples collected in Colombian pig farms contained from 184 to 317 g crude protein/kg DM, 469–620 g NDF and 98–145 g ash. Those of Salvinia contained from 112 to 169 g crude protein/kg DM, 518–629 g NDF and 161–232 g ash. The content in all macro- and micro-minerals were high and exceeded the pig's requirements expressed per kg diet. The proteins of the two species presented a similar amino acid profile and contained from 47 to 53 g lysine/kg protein, 11–17 g methionine, 53–55 g threonine and 14–15 g tryptophan. A digestibility study in 60 kg pigs was carried out with diets containing maize, soybean meal, minerals and 0, 125 or 250 g AF/kg diet. The weight and length of the digestive organs was also measured. The presence of AF decreased the faecal digestibility of crude protein, NDF and gross energy of the diet (P

The aim of this study was to evaluate the influence of bovine colostrum supplementation on the immune Th1/Th2 response in weaned piglets. After weaning at 21 d, 3 groups of 7 piglets were fed ad libitum with a starter diet and received daily 0, 1 or 5 g of spray-dried bovine colostrum. Spleen and gut-associated lymphoid tissues (GALT): ileal Peyer's patch (iPP), jejunum wall (M) and mesenteric lymph node (MLN)) biopsies were collected on each piglet after 3 wk of treatment and analysed for their cytokine mRNA expression (IL-2, IL-4, IL-10, IL-12 and IFN gamma) by RT-PCR. The supplementation with bovine colostrum induced an increase (P < 0.05) in IL-12 in the JW, in IL-2, IL-10 and IL-12 in the MLN and in IL-4, IL-10 and IL-12 in the iPP. In the latter, bovine colostrum also decreased IFN gamma production (P < 0.01). Finally, no effect of the treatments was recorded in the spleen. These results suggest an immunomodulatory effect of bovine colostrum on the GALT, which responded by producing at different levels both Th1 pro-inflammatory cytokines (IL-2, IFN-gamma and IL-12) and Th2 anti-inflammatory cytokines (IL-4 and IL-10). This Th1 Th2 bipolar response protects the weaned piglets from both allergic (food) and infectious (pathogens) diseases. (c) 2007 Elsevier B.V All rights reserved.

Two experiments were undertaken to investigate the influence of (1) pig bodyweight and (2) dietary fibre content of the diet on the in vitro gas production of sugar beet pulp fibre using faecal inoculum. In the first experiment, inocula prepared from young pigs (Y; 16–50 kg), growing pigs (G; 62–93 kg) and sows (S; 216–240 kg) were compared. Sugar beet pulp, hydrolysed in vitro with pepsin and then pancreatin, was used as the fermentation substrate. The cumulated gas productions over 144 h were modelled and the kinetics parameters compared. Lag times (Y: 4.6 h; G: 6.4 h; S: 9.2 h) and half-times to asymptote (Y: 14.7 h; G: 15.9 h; S: 20.8 h) increased with pig bodyweight (P In the second experiment hydrolysed sugar beet pulp was fermented with four inocula prepared from pigs fed diets differing in their total and soluble dietary fibre contents, i.e. low fibre diet rich in soluble fibre (LOW-S) or in insoluble fibre (LOW-I) or high fibre diet rich in soluble fibre (HIGH-S) or in insoluble fibre (HIGH-I). The total and the soluble dietary fibres influenced the kinetics of gas production. The presence of soluble fibres decreased the lag times, whatever the total dietary fibre content (2.7 h for LOW-S versus 3.5 h for LOW-I, 4.0 h for HIGH-S versus 4.4 h for HIGH-I; P In conclusion, the bodyweight of the faeces donors and the dietary fibre composition of the pig diet influence the in vitro fermentation kinetics of hydrolysed sugar beet pulp, but not the final gas production.

Two experiments were undertaken to adapt the in vitro gas production technique in syringes, used for ruminants, to fibre fermentation studies in the large intestine of pigs. In a first experiment, two inocula (faeces and large intestine content) were compared at four dilution levels in a buffer solution (0.025, 0.05, 0.1 and 0.2 g ml−1) with two substrates: wheat bran and sugar–beet pulp. The accumulated gas produced over 72 h was modelled and the kinetics parameters compared. The time to half asymptote was lower for the intestinal inoculum (5.5 versus 8.0 h, P 0.05) was observed between inocula and substrates. The dilution of the samples in the buffer solution increased (P A second experiment aimed to study the effect of an in vitro pepsin–pancreatin hydrolysis of the sample prior to the gas test. Six substrates were tested: maize, wheat bran, sugar–beet pulp, lupins, peas and soybean meal. The enzymatic hydrolysis affected (P In conclusion, the method using faeces as a source of microbial inoculum is reliable to characterise the fermentation kinetics of ingredients in the large intestine of pigs. However, it is important to hydrolyse the substrates with pepsin and pancreatin before the gas tests.

A total of 68 species of starchy foods, tropical fruits, leaves and tubers (101 samples), were collected on the foothills of the Colombian Andes and in the rain forests of the Colombian Pacific coast. Their edible portion was analyzed for mineral content (Ca, P, Mg, K, Na, Cl, S, Mn, Zn, Fe, Cu, Se, Co, Ni). The foods were generally high in K (36–1.782 mg K/100 g edible portion) and low in sodium (

Six male goats, fitted with ruminal cannulae, were used to study effects of feed block supplementation on the ruminal ecosystem of browsing goats during spring. Ruminal fermentation parameters (i.e. pH, ammonia N, and volatile fatty acids (VFA)) in rumen liquor were measured monthly three times in a day (i.e. 0, 2 and 6 h after starting shrub land pasturing). A rumen in situ technique was used to examine disappearance of dry matter (DMD), crude protein (CPD), and organic matter (OMD), and rate and extent of gas production was studied. The browse species evaluated were Arbutus unedo, Calycotum villosa, Cistus salvifolius, Erica arborea, Phillyrea angustifolia, Pistacia lentiscus, Myrtus communis, and Quercus suber. There were no effects of feed blocks on ruminal pH, NH3–N and VFA concentrations. Browse species varied widely in CP (55–221 g/kg DM) and condensed tannin contents (10–383 g/kg DM), but DMD, OMD and CPD did not differ in unsupplemented vs. supplemented goats. There was also no effect of the origin of the rumen inoculum (i.e. from unsupplemented vs. supplemented goats) on patterns of gas production. Feed block supplementation did not affect the ruminal ecosystem of goats browsing on shrub land during the growing season due to either sufficient nutrients consumed without supplementation, or the inability of feed block supplementation to inactivate tannins in the browse species.

Two experiments were conducted to investigate the effects of PEG and feed blocks on digestion of shrub species consumed by goats (experiment 1) and kid growth while browsing during the dry season (experiment 2). In experiment 1, in vitro gas production was determined using a rumen fermenter. Six shrub species were incubated separately ( Erica arborea , Phillyrea angustifolia , Pistacia lentiscus , Myrtus communis , Quercus suber , and Viburnum tinus ). Effects of polyethylene glycol (PEG 4000) and feed block supply were investigated. In experiment 2, 21 local kids, 18.75 (±1.4) kg body weight (BW) were allowed to browse in shrub-lands and allocated to three treatments in a production trial lasting 147 days (July–December). Control group receive no supplement, whereas the two other groups received either PEG-free (B) or PEG-containing feed blocks (B-PEG). All shrubs were low in crude protein (59–91 g kg −1 dry matter) but high in total condensed tannins; mean content was 43 g kg −1 DM (8.8–65) for bound condensed tannin and 205 g kg −1 DM (10.8–363) for free condensed tannin. Gas volume produced after 24 h differed among shrub species (P V. tinus produced the highest volume (77.8 ml g −1 organic matter) and Q. suber the lowest (35 ml g −1 OM). The mean rate of fermentation was 0.135 h −1 (0.121–0.150 h −1 ). PEG addition increased gas production by 48.5%, volatile fatty acid by 38.4% and organic matter fermented by 41.7% of the mixture of shrubs (P −1 , the bloc supplemented groups grew at 12 g day −1 (−PEG) and 24 (+PEG) g day −1 .

In vitro gas production of seven species (i.e., Arbutus unedo, Calycotum villosa, Erica arborea, Phillyrea angustifolia, Pistacia lentiscus, Myrtus communis, Quercus suber) that are widely browsed by goats were measured through 120 h and related to in situ dry matter disappearance (DMD) and chemical composition. Three goats fitted with ruminal cannulae were used for the in vitro and in situ studies. Browses varied in their crude protein (CP: 55–221 g/kg DM) and neutral detergent fibre (360–551 g/kg DM) contents. High levels of total condensed tannins (TCT) were observed in Pistacia lentiscus, and the lowest levels were in Calycotum villosa and Phillyrea angustifolia. The browses varied widely in potential (145.7–224.0 ml/g DM) and fractional rates (0.038–0.075/h) of gas production, and there were differences among species in DMD (P

Yearly nutrient balances were established between August 1979 and October 1981 for the organic layers of beech and spruce forests. Principal component analysis has been applied to the monthly nutrient balances in order to understand the important differences which appear between both types of organic layers. Three main processes affect the redistribution of elements from the organic layers: exchange and solubilization, organic matter mineralization and nitrate immobilization and release. The relative importance of these three processes within the beech and the spruce layers is different. Moreover, it is shown that variations in the rainfall regime is an important factor which govern nitrogen redistribution and that rainfall acidity promotes phosphate leachings from the organic layers of both forests.

The leaching of nutrient cations (Na + , K + , Mg 2+ and Ca 2+ ) from undisturbed beech and spruce litters was followed in relation to the following environmental factors: nature of the organic layers, temperature, rainfall, quality of rain and stage of humus development. Among them, temperature, quality of rain and type of humus were predominant in modifying leaching rates of the nutrients. But, when the time of sampling was considered, the effects of physical, chemical and biological transformations of the humus on the leaching of cations had to be accounted for. The complexity of the interactions occurring during leaching is also exemplified.