Theoretical and Experimental Studies of the Temperature Difference at the Inlet and Outlet of a Pump as a Function of Time and Pressure

In the article, the characteristics of the function of temperature difference of a working fluid at the inlet and outlet of gear pumps with different efficiency and at different pressures are theoretically and experimentally investigated. A method is proposed for determining the efficiency of pumps during its operation at variable pressure, based on the hypothesis that the performed useful work of the pump is characterized by the area under the pressure curve, and the lost energy is the area under the temperature difference curve.

Utilizing Asphalt Heat Energy in Finnish Climate Conditions

Geothermal energy is a form of renewable energy, which offers carbon-free solutions for heating and cooling spaces. This study evaluates the use of renewable asphalt heat energy in frozen ground conditions. Asphalt heat energy can be harnessed using a low-energy network, heat collection pipes and heat pumps. This study measured temperatures under the asphalt layer during a three-year period between 2014 and 2017. Measurements were made using a distributed temperature sensing method based on light scattering. Temperatures taken at four different depths under the asphalt (0.5 m, 1.0 m, 3.0 m and 10 m) are presented here. These temperatures are compared with that detected at the depth at which the temperature remains constant all year round. The temperature difference curve between 0.5 m depth and the constant soil temperature depth indicates that from April to October the soil at 0.5 m depth is warming and the temperature difference is positive, even as much as 18 °C. Instead, at the 3.0 m depth, the difference curve is smoother and it varies only from −5 to +5 °C. It is positive from June to November. The surface layer (0 m–1.0 m) is suitable for harvesting heat that can be stored in a deeper (1.5 m–3.0 m) purpose-built storage or in a bedrock heat battery. The calculated heat capacities indicate that asphalt energy, because of high temperatures, is a noteworthy renewable energy source.

Effect of machine speed on formation and strength efficiency in twin-wire roll forming of never-dried unbleached softwood kraft pulp

There is a constant drive to increase machine speed in the production of kraftliner and most other major paper grades, but the separate effect of the machine speed on the paper properties has been unclear. The effect of machine speed in twin-wire roll forming of never-dried unbleached softwood kraft pulp was evaluated here in a pilot machine investigation by examining three machine speed levels (500, 750, and 1000 m/min) over a series of jet-to-wire speed differences. Similar headbox consistency and draw from wire section to winding were employed at the different machine speed levels. An increase in the machine speed had a favorable effect on formation and Z-strength efficiency over a wide range of jet-to-wire speed differences, whereas the machine speed had an insignificant effect on tensile strength efficiency and tensile stiffness efficiency. For all properties, the overall shape of the jet-to-wire speed difference curve remained similar when changing the machine speed.

Strain modal-based damage identification method and its application to crane girder without original model

Although there are many methods to identify structural damage of the crane girder, almost all of them are used by means of comparing specific parameters of original and existing structures. And it leads to difficulties in practice. So, a method to identify damage of the crane girder is proposed based on strain modal without original model. First, the strain modal difference curve was obtained by using difference algorithm to deal with strain modal and cubic spline interpolation algorithm to fit the curve, and the damage location was realized by constructing and comparing damage sensitive index (IDSI). Then, the data of undamaged checkpoints adjacent to damaged checkpoints are stationary and modeled by Auto-Regressive Moving-Average Model, with this modeling the original data of the damaged checkpoints was predicted, and variation of the got strain modal difference curve was used to determine damage degree. Finally, the application of this method was implemented by some experiments and numerical calculations, and the results demonstrated that this method can effectively identify the damage of the crane girder.

Testing Equality of Curves after Covariate Adjustment

SummaryThis paper is concerned with providing simple methodological approaches for global and local tests of difference between the mean of treatment and control groups when the measured outcome is a function. The added complexity is that for every subject we have repeated samples for the same curve and additional covariates of interest. We propose a permutation based approach to test for a global difference between the averages of two functional processes after covariate adjustment. The within group averages are estimated by modeling the relationship of the functional outcome on the covariate using functional regression methods and then averaging with respect to the covariate distribution in each group. The test statistic is the L2 area under the squared difference curve. We also test for the localized differences between the two average curves using a nonparametric bootstrap of subjects to obtain the 95% pointwise and joint confidence intervals for the estimated covariate-adjusted difference curve. Extensive simulation studies illustrate that the proposed tests preserve the type one error and are highly sensitive to detecting departures from the null assumption. We illustrate our method by studying the differences in time varying oxygen consumption between the frail Interleukin 10tm1Cgn (IL10tm) mice and the wildtype mice after adjusting for body composition measures.

Numerical Simulation on Interface Delamination of Composite Foam Sandwich Tube under Axial Load

The compressive capacity of composite foam sandwich tube is influenced by the fabrication process. Foam sandwich composite tube is made with technology of filled foam precut and curing molding together with prepreg ply. In order to clarify the interface to the bearing capacity, dynamics finite element software LS-DYNA was used to simulate the model whose interface is polished and waxed or not. The delamination was observed by the deformation cloud picture and displacement difference curve. The simulation showed that the composite foam sandwich tube which interface was polished and waxed before it was formed has relatively higher carrying capacity than that none-polished and none-waxed.

Research on Curvature Mode Characteristics of Damaged Simply Supported Beam

This paper approaches the rules of curvature mode and curvature mode difference about a simply supported beam. On the basis of the theory of curvature mode, through numerical simulation analysis of simply supported beam on four conditions, the result of simply supported beam with curvature mode and curvature mode difference were obtained. The results show that for the damaged beam information with numerical simulation, the curvature mode and curvature mode difference index calculated by difference method at the unit length unevenly is with strong noise, which can even submerge the beam damage information, and for different damage index of the beam, damage information from curvature mode difference curve is stronger and effected by unit length weaker than those from curvature mode curve, and damage information from curvature mode curve and curvature mode difference curve decrease with the increasing mode order.

The Temperature Distribution Research of Foaming Gypsum Mold in the Fabrication and Pouring Process

This paper describes study of temperature variation in the gelling and hardening, thermal baking and pouring stage of foaming gypsum mold. The temperature difference curve in the gelling and hardening process shows an rapid decline, tending to the placid downward eventually after a clipping rise. During the thermal baking stage, owing to the low heat conduction coefficient of the foaming gypsum mold, the actual temperature of each thermocouple lags behind the craft temperature, lag degree increases gradually with the extension of baking temperature and holding time. At the initial period of pouring process for molten aluminum, the temperature of center position in the mold increases fast by absorbing lots of heat in the solidification process, whereas, slower temperature rising curve occurs in the edge and intersection position. Coupled with the ongoing of air convection heat transfer, resulting in a continuous falling of temperature, therefore the temperature difference curve of each point inside the mold shows a successive upward trend with the solidification process of molten aluminum alloy.

A Quick Edit Method of Curve Network’s Interpolated Surface Based on Combined Subdivision

A simple and effective combined subdivision surface’s modification method is proposed, which is realized by editing its curve network locally. After discussing the overlapping principles of Catmull-Clark subdivision and combined subdivision, a quick update method of the modified surface is given by building the difference curve network from the original curve network and the edited curve network and overlapping the mesh from the difference curve network to the mesh from the original curve network. This method is closely related with the features of combined subdivision, so it is simple and high efficiency. It is useful in the concept design of complex product.