Torque Prediction Model of a CI Engine for Agricultural Purposes Based on Exhaust Gas Temperatures and CFD-FVM Methodologies Validated with Experimental Tests

A truly universal system to optimize consumptions, monitor operation and predict maintenance interventions for internal combustion engines must be independent of onboard systems, if present. One of the least invasive methods of detecting engine performance involves the measurement of the exhaust gas temperature (EGT), which can be related to the instant torque through thermodynamic relations. The practical implementation of such a system requires great care since its torque-predictive capabilities are strongly influenced by the position chosen for the temperature-detection point(s) along the exhaust line, specific for each engine, the type of installation for the thermocouples, and the thermal characteristics of the interposed materials. After performing some preliminary tests at the dynamometric brake on a compression-ignition engine for agricultural purposes equipped with three thermocouples at different points in the exhaust duct, a novel procedure was developed to: (1) tune a CFD-FVM-model of the exhaust pipe and determine many unknown thermodynamic parameters concerning the engine (including the real EGT at the exhaust valve outlet in some engine operative conditions), (2) use the CFD-FVM results to considerably increase the predictive capability of an indirect torque-detection strategy based on the EGT. The joint use of the CFD-FVM software, Response Surface Method, and specific optimization algorithms was fundamental to these aims and granted the experimenters a full mastery of systems’ non-linearity and a maximum relative error on the torque estimations of 2.9%

Associação entre o California Mastitis Test e a Contagem de Células Somáticas na avaliação da saúde da glândula mamária caprina

The relationship between the California Mastitis Test (CMT) and the somatic cells count (SCC) was studied in milk samples of 68 dairy goats of Anglo Nubian, Brown Alpine and Saanen breeds. The samples were collected twice a month, during seven months and tested by CMT, microbiological culture and SCC. Only milk samples negative in the microbiological examination were considered in the analysis. The results showed a significant positive correlation (p < 0.05) between CMT and SCC (r = 0.63), and a negative correlation (p < 0.05) between CMT, SCC and daily milk production (r = -0.27 and r = -0.28). In the association between the CMT and SCC it was obtained a mean of 0.78 x 10(6) cell/ml for the negatives reactions (N, T and 1+) and 5.32 x 10(6) cell/ml for the positive reactions (2+ and 3+). The results showed that in order to avoid the false positives results, other diagnostic test must be done together with CMT test to evaluate the goat milk to detect subclinical infections.A correlação entre os resultados do California Mastitis Test (CMT) e da Contagem de Células Somáticas (CCS) foi estudada em 68 cabras das raças Anglo-Nubiana, Pardo Alpina e Saanen. Os dados foram coletados quinzenalmente, durante sete meses, realizando-se a CCS em amostras de leite bacteriologicamente negativas. Os resultados mostraram uma correlação positiva e significativa (p < 0,05) entre os testes avaliados, com um coeficiente de r = 0,63. Quando os testes foram correlacionados com a produção de leite, observou-se uma correlação negativa e significativa (p < 0,05) de r = -0,27 e r = -0,28 para o CMT e a CCS, respectivamente. Na associação das reações do CMT com a CCS obtiveram-se médias de 0,78 x 10(6) céls/ml para as reações negativas (N, T e 1+) e média de 5,32 x 10(6) céls/ml para as reações positivas (2+ e 3+). Os resultados indicam que, para evitar resultados falso-positivos, outros testes diagnósticos deverão ser usados juntamente com o CMT, para se avaliar a saúde da glândula mamária caprina

Catastrophic NAD+ Depletion in Activated T Lymphocytes through Nampt Inhibition Reduces Demyelination and Disability in EAE

Nicotinamide phosphoribosyltransferase (Nampt) inhibitors such as FK866 are potent inhibitors of NAD+ synthesis that show promise for the treatment of different forms of cancer. Based on Nampt upregulation in activated T lymphocytes and on preliminary reports of lymphopenia in FK866 treated patients, we have investigated FK866 for its capacity to interfere with T lymphocyte function and survival. Intracellular pyridine nucleotides, ATP, mitochondrial function, viability, proliferation, activation markers and cytokine secretion were assessed in resting and in activated human T lymphocytes. In addition, we used experimental autoimmune encephalomyelitis (EAE) as a model of T-cell mediated autoimmune disease to assess FK866 efficacy in vivo. We show that activated, but not resting, T lymphocytes undergo massive NAD+ depletion upon FK866-mediated Nampt inhibition. As a consequence, impaired proliferation, reduced IFN-γ and TNF-α production, and finally autophagic cell demise result. We demonstrate that upregulation of the NAD+-degrading enzyme poly-(ADP-ribose)-polymerase (PARP) by activated T cells enhances their susceptibility to NAD+ depletion. In addition, we relate defective IFN-γ and TNF-α production in response to FK866 to impaired Sirt6 activity. Finally, we show that FK866 strikingly reduces the neurological damage and the clinical manifestations of EAE. In conclusion, Nampt inhibitors (and possibly Sirt6 inhibitors) could be used to modulate T cell-mediated immune responses and thereby be beneficial in immune-mediated disorders

Concurrent Engineering Approach in Design of Test Equipment for Detecting Farm Tractors Mechanical Performances: Application to Development of Hub-Adapter

The development of a test system to complete existing equipment in a research laboratory is a real design-activity, with even high complexity levels and many constraints, in terms of resistance to mechanical stresses and geometric connectivity to existing mechanical interfaces as well. Such a project must also be focussed, if possible, on cost saving and realisation speed, to make the best possible use of research funds, having often a limited time-availability. Concurrent Engineering (CE), born in the early 90s, is as a well-defined system approach to optimize the design and engineering cycles, with emphasis on tasks parallelization. In particular, CE revolves around the concept of considering all elements of a product lifecycle in the early design phases. By doing so, the resulting project is virtually free from design errors, which are expensive to be corrected in existing components and critical for the success of that project. The “Theory of Inventive Problem Solving” or TRIZ includes a practical methodology, some tools, a knowledge-base and a model-based technology for generating innovative solutions for problem solving. CE and TRIZ together can be particularly-effective also in the design of unique components, e.g. those composing the equipment of a research laboratory. This work illustrates the approach followed in defining a component of a system to measure the agricultural machinery performance. This rig will connect the rear wheels of a tractor to an existing PTO-dyno through two multiplication stages. In particular, the cited methodologies have been applied in the development of a hub adapter, i.e. the element that interfaces with the machine in test. The research for technical documentation and standards, the direct measurement of existing parts, the computer-aided design with 3D-modelling and finite element calculation of the components, have allowed to obtain iteratively a project verified in all aspects, ready to be realized

Some Metrological Observations on the Use of the Exhaust Gas Temperature for the Indirect Measurement of the Torque in Agricultural Engines

The temperature of the exhaust gases can easily be correlated to the torque that an internal combustion engine is instantaneously delivering. Therefore, the temperature measurement is a concrete and viable possibility for indirectly quantifying the performance of agricultural machinery, even in terms of retrofitting, if the considered farm tractor is not natively equipped with any electronic system to interface with. The positioning of a thermocouple along the exhaust line must, however, be accompanied by a series of technical considerations and preliminary trials to test its main metrological characteristics (firstly: its “time constant”) and, hence, its overall suitability. The experimental campaign carried out in this study involved the characterization of a K-type thermocouple in water (at the temperature of melting ice and at the boiling point) and, then, in an installation close to the one which could be used for an endothermic engine performance monitoring system, i.e., along the exhaust line. Both the thermowell and the installation setup have a non-negligible influence on the overall time constant of the sensor: the former increases the time constant by 12.8 times, the latter by a factor of 42.5 with reference to the thermocouple alone. This evidence has interesting implications for possible installations of a monitoring system, starting with the possibility of using more conductive metals for the thermowell or even installing the thermocouple without any thermowell to purse the maximum possible quickness of response for this sensor

Assessment and Classification of Farm Tractor Rims for Mechanical Testing

The propulsion system of an agricultural machine is in charge for the delivery of the engine power to the soil and allows a vehicle travelling and performing its duties. Based on the type of this system, agricultural machines can be divided in tracked and wheeled. Although the former have their own specific applications and advantages, the latter are the most widely used. Over the time, different tyre typologies have been developed keeping into account many factors, such as tractor models, sizes and types of field/tillage operations, and wheel rims were changed accordingly. Notwithstanding an attempt of standardization by ISO, the design of these components is still conditioned by manufacturers’ previous choices and there are some interchangeability issues. The knowledge of existing differences/dimensions is useful when there is the need for maintenance, substitution or connection of whatever device to a tractor axle. So, with the aim of developing a universal piece of experimental equipment to be used to detect the tractor performances (torque, power) at the wheels, i.e. a hub adapter, a systematic study of the different rim types has been performed. After having collected many data through direct measurements or interviews, all information has been elaborated using many statistical tools, such as scatter plots, frequency charts and clustering algorithms. Finally, four different classification keys have been applied to identify a minimum set of dimensional/functional classes of tractors using similar rims and, hence, capable of using the same hub adapters. The results of this study were then successfully used to design two optimized adapters. Their features (dimensions, number of holes) would let these two adapters connect the test equipment to the axle shafts of up to 1961 tractors of our database, corresponding to 81 % of the farm tractors below 100 kW on the Italian and European market, thus maximizing the cost-benefit ratio for these components