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The motion of the lymph has a very important role in the immune system, and it is influenced by the porosity of the lymph nodes: more than 90% takes the peripheral path without entering the lymphoid compartment. In this paper, we construct a mathematical model of a lymph node assumed to have a spherical geometry, where the subcapsular sinus is a thin spherical shell near the external wall of the lymph node and the core is a porous material describing the lymphoid compartment. For the mathematical formulation, we assume incompressibility and we use Stokes together with Darcy–Brinkman equation for the flow of the lymph. Thanks to the hypothesis of axisymmetric flow with respect to the azimuthal angle and the use of the stream function approach, we find an explicit solution for the fully developed pulsatile flow in terms of Gegenbauer polynomials. A selected set of plots is provided to show the trend of motion in the case of physiological parameters. Then, a finite element simulation is performed and it is compared with the explicit solution.

The aim of the paper is to propose a mathematical model for the flow of the interstitial fluid in a lymph node, which main feature is the presence of a porous bulk region with a very low permeability, surrounded by a thin channel where the fluid can flow freely. The flow is driven by a pulsatile pressure gradient. An explicit solution is found in the case of a laminar flow in a simplified situation, while some finite element simulations are presented in a more realistic geometry.

One challenge for the Ford chassis research team in the recent past was to investigate lightweight solutions for the upcoming Transit platform, for the end customer benefits of higher payload, reduced emission and better fuel consumption. As first application within the platform, the Camper /Motorhome was chosen. One of the promising items which was looked at were the rear longitudinal leaf springs. Replacing the standard steel springs with equivalent parts in composite material, generated a weight saving of about fifty percent, or about fifteen kilograms per vehicle. The spring had to be entirely redesigned, to obtain best in class performance, considering the new material properties and limitations. The project covered all the necessary steps, from the first research state to series implementation. Three important aspects which are discussed here are the design, the testing and finally the manufacturing process.

8th International Conference on Fatigue Design, Fatigue Design 2019, Senlis, France, 20 Nov 2019 - 21 Nov 2019; Procedia structural integrity 19, 645-654 (2019). doi:10.1016/j.prostr.2019.12.070 special issue: "Fatigue Design 2019, International Conference on Fatigue Design, 8th Edition / Edited by Fabien Lefebvre, Pascal Souquet Cetim", Published by Elsevier, Amsterdam

The objective was the development of a new suspension architecture for Ford’s global CD platform. This suspension architecture was required to improve vehicle driving comfort and noise without compromising the high level of steering and handling performance of the Ford Mondeo to date. Moreover, the new suspension architecture had to fulfil a number of challenging package requirements. The newly developed rear suspension is an integral link suspension. This is an independent suspension system connecting a wheel carrier to an isolated subframe by means of a lower control arm, a camber link and a toe link. The wheel carrier is directly connected to the lower control arm via a pivot point and indirectly via an additional link, the integral link. This link decouples castor compliance from longitudinal compliance and prevents the need for a trailing link or control blade. The most important result is a substantial reduction of cruising interior noise. Impact harshness, noise and aftershake have significantly improved. The improvements in vehicle comfort have not affected the vehicle steering and handling performance. As a result, the new Ford Mondeo suits both relaxed and sporty driving styles.

The reactivity of zirconia-supported RH 4 (CO) 12 and Mo(CO) 6 has been studied by temperature-programmed desorption (TPD) into vacuum and temperature-programmed reaction (TPR). Thermal activation of the carbonyl precursors results in a complex reaction system including CO disproportionation, water gas shift reaction and oxidative interaction of Rh o species with hydroxyl groups on the support. The surface species formed after chemisorption of CO on the reduced samples exhibit different reactivity compared with the original metal carbonyls. K 2 O added to ZrO 2 promotes the shift reaction and selectivity to methanol but suppresses CO hydrogenation; Mo(CO) 6 co-adsorbed with Rh 4 (CO) 12 brings on formation of surface sites exhibiting weak adsorption properties towards CO and high hydrogenation activity. TPR experiments in flow of H 2 -CO mixture show that above 500 K the thermodynamically favoured products CH 4 and CO 2 rapidly become predominant; however, with RhMo/ZrO 2 , a good selectivity to oxygenated products can be obtained in a restricted temperature range by operating at high CO pressure.

In hydrotreating heavy crudes, shale oils and coal liquefaction products, the cost of the catalyst is expected to be a critical factor in the process economy. This is due to non-volatile metal components in the feedstocks which cause high catalyst consumption. In a systematic study of the use of natural bauxite as carrier for low cost hydrotreating catalysts, the catalytic performance of bauxite-based catalysts in hydrotreating a 60% reduced crude from the Adriatic Sea region has been determined in a trickle-bed reactor. The following systems have been considered: MoO 3 /bauxite, WO 3 /bauxite, CoO-MoO 3 /bauxite, NiO-MoO 3 bauxite, NiO-WO 3 /bauxite. Data on a commercial catalyst,containing 4 and 12 wt % of CoO and MoO 3 respectively, are included for comparison. For maximum surface dispersion of the active components, Mo(VI) and W(VI) were incorporated on bauxite by anionic exchange. The Mo(VI) and W(VI) contents of the catalysts (6.6 wt % MoO 3 and 11.6 wt % WO 3 ) correspond to the chemisorption capacity of the natural material (after thermal activation). The catalytic properties of the bauxite-based catalysts resemble those of alumina-based catalysts. The synergistic effect of cobalt and nickel on molybdenum and tungsten in hydrodesulfurization (HDS) is evident. Tungsten-based catalysts are less active than molybdenum-based systems, in accordance with literature data. The lower activity of all bauxite-based catalysts, compared with the commercial CoO-MoO 3 -a1umina system, is attributed to differences in composition and surface properties. All of the catalysts examined promoted the production of a low boiling fraction in similar amounts, i.e., all catalytic systems show similar cracking activity. However, hydrogen uptake, as measured by the increase of the H/C ratio of the product, is substantially different and suggests large differences in the hydrogen-ating activity of the catalysts. Activity in hydrodenitrogenation (HDN) is lower than in HDS. Also the nitrogen removal properties of bauxite-based catalysts are comparable with the alumina-based systems. Differences in the kinetic steps involved in the HDS and HDN processes have been proposed; the experimental data indicate that the nitrogen removal process takes place through a number of kinetically important steps and this is consistent with the reaction network proposed for the HDN of model compounds. In metal removal, bauxite-based catalysts exhibit about the same activity as the commercial catalyst; this result is attributable to the relevant role played in this reaction by the pore structure of the support. These data show that, by the use of appropriate evaluation criteria, natural minerals, such as bauxites, can be selected to prepare efficient hydrotreating catalysts and that the activity and selectivity of these systems can be, to a certain extent, adjusted by a proper choice of chemical composition.

IR spectra of toluene, ethylbenzene and styrene adsorbed on pressed discs of hematite between room temperature and 400°C are described. Mechanisms of adsorption and transformation are discussed and compared with those reported on the basis of kinetic measurements of ethylbenzene dehydrogenation on iron oxide catalysts.

Extensive investigations of the “Seveso mixture” by advanced thermoanalytical techniques and engineering experiments allow an explanation of the Seveso accident and a definition of the criteria for conduction of the process for the production of 2,4,5-trichlorophenol. A critical comparison of the process in methanol and in ethylene glycol as reaction medium points to the latter as being more controllable and consequently safer.

Benzene adsorption on α-Fe2O3 in the temperature range 300–673 K has been studied. Two different molecular adsorbed forms can be distinguished due to their spectroscopic behavior and the different equilibrium pressures needed for their formation. The more stable form, in which the benzene molecule is π-bonded on exposed metal cations, slowly transforms at room temperature into combustion products. This process is inhibited by the presence on the surface of the second form of adsorbed benzene.

Coal and catalysts are examples of substances of great technical importance, whose knowledge has advanced for many years empirically. They are considered as disordered and complex materials. FT-IR/PAS suggests models closer to the real systems as the samples can be examined “as they are”: coal with the same sampling procedure as for ASTM analysis and catalysts “during catalysis” without manipulation. Some examples are reported.

Etude par thermogravimetrie, calorimetrie differentielle a balayage, de la stabilite thermique des chlorures et bromures nitro benzyliques

A sample of bauxite, containing 28% Fe 2 O 3 , was activated by hydrothermal treating and molybdenum impregnation, and tested as a catalyst in the hydro-treating of a heavy petroleum residue in a bench-scale trickle-bed reactor. The thermally treated bauxite exhibited a significant demetalation activity, attributable to iron sulfide. After addition of a small amount of molybdenum (4.7% MoO 3 ) to the activated bauxite, hydrodesulfurization was strongly promoted. At highest conversion, hydrogen consumption was less than 100 Nm 3 /m 3 of oil. NMR analysis of the products showed a limited saturation of aromatic rings. Hydrocracking, significant in the presence of activated bauxite, was somewhat reduced by molybdenum addition.

The use of cobalt and rhodium catalysts derived from carbonyl clusters and supported on Al2O3, Al2O3–ZnO, ZrO2 and SiO2 for the CO + H2 reaction has been investigated. Only Rh-containing catalysts were active in the formation of oxygenated compounds (essentially ethanol). In all the runs the selectivity to methane plus ethanol was > 90%. The ratios of the rates of ethanol and methane formation or the rate of ethanol formation and the CO reaction reach a maximum when equal amounts of Rh and Co are present on the catalyst surface. Cobalt alone does not form oxygenates, but when mixed with rhodium it increases the selectivity to ethanol.