1,721,151 research outputs found
Advance in Soil & Tillage Research
No full textIn this report a numerical simulation of the
interaction between soil and plough mouldboard has
been performed by utilising "finite volumes"
numerical approach. Simulation has been carried out
by utilising a 3D-free-surface model as well as a
medium soil with constitutive relationship of no-
Newtonian pseudo-plastic material. As a matter of
fact that "virtual" material could properly simulate
either the effects of the adhesive and internal friction
of the examined soil (sandy soil). Full field tests have
been performed to actually validate the aforementioned
experimental model. Piezo-resistive transducers have been used to detect the pressure values on 14 points located on plough mouldboard working surface. Besides, obtained pressure distribution deriving by spatial interpolation on working surface has been compared with numerical simulation data results.
The maximum error detected while comparing numerical results and experimental data set has been less than 10 %. This procedure allow to study the problem of optimising geometrical shape of working surface while reducing input costs. In this way it is possible to minimize either draught force and the energy spent
Ottimizzazione Tecnologica e Produttiva di Macchine per la Criomacerazione delle uve mediante l'iniezione diretta di CO2
No full textvalutazioni tecniche di macchine per la criomacerazione delle uve mediante iniezione diretta di CO2, in condizioni termodinamiche differenti
No full textMessa a punto di un’apparecchiatura per lo studio delle caratteristiche meccaniche dei terreni insaturi.
No full textSimplified triaxial apparatus to test agricultural soils
No full textA simplified cell for triaxial testing of soil samples has been developed. The apparatus allows the initial volume of the sample and the changes in volume that take place during both hydrostatic and triaxial compression tests to be measured, with an accuracy of 0.1 cm3. All samples prepared have been obtained and precompacted using a standardized procedure and the results plotted in diagrams. Thus, the behaviour of agricultural soil and how it reacts to principal stress could be determined. The results of triaxial tests on different samples, specifically prepared with loose sandy soil of given composition and water content, using the simplified apparatus, are examined. The equipment was not expensive and easy to use and it also had the same degree of accuracy as other commercially available equipment
Rheological analysis to monitor the leavining process of pizza dough prepared in different conditions
No full textTo appraise the effects of the microbial activity on rheological characterustics of pizza dough, it has been set an opportune equipment denominated "modified alveograph". It allows, through opportune acquisition and elaboration of the data, to evaluate contemporaly both the pressure (Dp) of the air blowed that acts on a disk of standard test piece of pizza dough and either the consequent variation of volume (DV) of the bubble of pizza dough considered up to its brek-up. The experimentation has interested the rheological evaluation of pizza dough performed in standard conditions (raw material and technology of production) and whose only variable is represented by the use of different starters selected that are able to influence with different formality, the mechanical and acidimetric characteristics of the pizza dough considered
Sul calcolo grafico dell’interferenza d’accoppiamento
No full textIn merito alla determinazione dell'interferenza da realizzare tra corpi tubolari destinati ad accoppiarsi per forzamento si prospetta una soluzione grafìca atta sulla base di elementarissime costruzioni geometriche a visualizzare la cedevolezza dell'uno come dell'altro elemento della coppia
Messa a punto di un’apparecchiatura per lo studio delle caratteristiche meccaniche dei terreni insaturi.
No full textStudy of Rope Joints for Forestry Aerial Ropeway
No full textIn this article the problem of ropes joints for forestry aerial ropeway plants has been studied. The existing legislation defines in way uniform the design criterions related to the ropes in the ropeway sector. Such norm covers all the aspects related to this matter, from the criterions of sizing, to the specifications related to the top connection and to the rope splice, to the check methods and the cut off criterions. Indeed in this study a procedure it has been set up that allows with a simple algorithm to reach the formulation of the bending maximum stress rising in the joints muffs for line of the ropeway plants. In fact considering the different lines has been possible to obtain four differential equations, with second order, non homogeneous, that have been integrated with the method of the variation of the constants. For them the constants of integration have been determined calculating in correspondence of every section of transition, the deflections and the rotations of the lines that meet in it. In such way making some positions it is possible to obtain a correct formula for this case considered. Such formula is nevertheless interesting because its structure recalls that simpler and summary of Isaachsen and therefore easy results the comparison with it. By mean the computational program FEMLAB has been possible to verify the stress course inside the rope
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