Search results

The problem of estimating mechanical properties of buildings materials is a major issue in civil engineering, especially when dealing with existing structures.
Introduction When dealing with existing building structures, or with buildings materials quality control, Non Destructive Testings (NDT) are powerful tools for evaluating mechanical parameters of materials and structures without affecting buildings functionality and serviceability.
It has been noticed, for example, that moisture content leads to an underestimation of Ir and to an overestimation of V; similarly, concrete age leads to Ir increasing and V decreasing; concrete carbonation adversely affects Ir, which increases becoming less representative of the strength.
The parameter a represents a scaling factor, while the parameters b and c correspond to strength percentage variations induced by a unitary percentage variation of experimental values of V and Ir respectively.

Published literature is rich with investigations of mechanical properties of composites, but fewer publications are focused on thermal properties.
Their mechanical behaviours have some common features [7].
The properties of nanocomposites, like a normal composite, depend on its components and their interface properties.
Other factors may overshadow the potential advantages that these layers can offer to the thermal conductivity of nanocomposites.
The intention of this paper is to review and compare some correlations between two different nanocomposites in order to investigate how deeply we can understand the thermal transfer mechanisms in composites and the factors which affect their thermal conductivity.

The metal magnetic memory testing is based on magneto-mechanical effect and expected to solve the problem of evaluating the degree of fatigue damage [8-10].
In this paper, the normal component of magnetic field, Hp(y), is measured during dynamic tension test on the surfaces of ferromagnetic specimens with different stress concentration factors, in order to study the relationship between fatigue damage and magnetic signals, even to evaluate the fatigue initiation life.
It has high tension strength and good integrated mechanical property, which is usually applied in manufacturing critical heavy-duty gear and shaft components, also used for carburized bearing steel.
Many factors, such as heat treatment condition, machining process and transport situation, intensively affect the initial magnetic signal, therefore, all the specimens were inductive demagnetized before experiments in order to study the relationship between loads and magnetic memory signals in initial state [11].
The concentration factor, Kt, of specimen was 5.

The research has shown that the most convenient microstructure variables in the austenitic crystals of polycrystalline sample, affecting the microcrack deviation, are microstructure, crystallography and the homogenous length of slip bands.
From the analyses, we have carried out, follows that in the physical model of plasticity of polycrystalline materials the major factors are the process parameters (amplitude, frequency, temperature) as well as the crystallography of slip, deformation twinning and crack formation.
In this regard, a scale factor should necessarily be taken into account, since for large bodies brittleness increases while for small ones it decreases.
Starting from the above considerations, the scale factor acquires a significant importance for thinning of samples (mainly of TEM samples), while in this case internal stresses relax faster.
Such kind of study and accumulation of statistical data, will definitely contribute to the design of alloys with the improved physical and mechanical properties.

When these substances get into the soil, they migrate into groundwater, which causes them to enter the food chain, technogenically affecting all living things [1, 2, 3].
They are able to adapt to various environmental conditions and can survive in conditions of increased metal content due to their adaptive properties [4, 5, 6].
However, there are more significant factors that instantly create conditions for exceeding the concentration of heavy metals in the soil, which accordingly affects the biometric parameters of plants - these are military actions.
It is known that nickel, due to its structure and ability to accumulate and assimilate, is toxic for most types of plants, affecting the activity of amylase, protease and ribonuclease enzymes, thereby slowing down the germination of seeds and the growth of many crops [10, 11].
The choice of statistical analysis methods and software depends on a number of factors, including the type of data, the purpose of the study, and available resources.

The physical and chemical properties of soil are shown in Table 2.
Properties of soil Chemical properties SiO2 Al2O3 CaO K2O MgO P2O5 Fe2O3 TiO2 LOI Content (%) 76.22 10.512 0.193 2.373 - 0.076 4.057 0.756 5.8 Physical properties Specific gravity (g/cm3) Liquid limit (%) Plasticity index (%) Content (%) 2.315 35.3 18.1 Results and discussion Effect of sodium hydroxide-sodium silicate ratio on geopolymerization.
It was indicated that curing temperature is one of important factor on strength of geopolymer soil.
Rangan, Development and Properties of Low-Calcium Fly ash based Geopolymer Concrete, Research report GC-1, Curtin University of Technology, Perth, Australia, 2005
Hongling et al., Synthesis And Mechanical Properties Of Metakaolinite-Based Geopolymer, Colloids Surf.A: Physicochem .Eng.Asp, 268, (2005), p.1-6

The grain structure and intensities of the relevant magnetic texture of the hot band affect remarkable the resulting microstructure and texture in the cold rolled and annealed nonoriented electrical steel grades based on ferritic Fe-Si alloys.
The coiling or annealing after finishing the hot rolling process is an important factor, which gives rise to different grain structure across the thickness.
Introduction The magnetic properties of the finally fabricated Fe-Si steels critically depend on the microstructure and on the occurring texture components.
The resulting microstructure and texture is affected already by the hot rolling and the resulting thermal treatment after finishing the rolling process [1, 4].
The resulting grain structure and texture intensities are remarkable governed by gradients of strain and temperature during the thermo-mechanical process.

A CAE Approach for Pretest analysis of vehicle body frame vibration test LU Shou Wei 1, a, FENG Hui Hua 1,b , ZUO Zheng Xing 1,c , YUE Feng Lai 2,d 1School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China 2School of Mechanical Engineering, Tianjin University, Tianjin 300072, China alswwt007@163.com, bfenghh@bit.edu.cn, czxzuo@bit.edu.cn, dyuefl@163.com Keywords: vehicle body frame, pretest analysis, NVH Abstract: Pretest analysis is a crucial step of the process for experimental modal analysis, directly affect the test accuracy.
Introduction During the past decade, experimental modal analysis has been extensively investigated, aiming at the improvement of vehicle NVH property.
The main difficulty in this approach is uncertain of excitation location and sensor placement, which have significant impact properties of test specimen on modal testing and measuring accuracy, therefore many researches are conducted in measurement location optimize involved pretest analysis.
As a consequence, the scaling factor ak is also purely imaginary
Theoretically the signal of impact force in time domain approximate express as: (6) Fast Fourier Transform process as: (7) Impact energy distribution is decided by two factors which are impulse force width and amplitude.

Composites based on graphene have shown improved mechanical strength, electronic conductivity, and electrochemical properties [4-6].
The obtained nanocomposites present markedly improved crystallinity, rate of crystallization, mechanical properties, electrical conductivity and fire resistance.
The properties are dependent on the dispersion and loading content of graphene, showing percolation threshold at 0.08 wt%.
Graphene reinforces the nanocomposites but cuts down the interactions among the polymer matrix, which leads to reduced mechanical properties.
However, the major drawback affecting the practical applications of SnO2 is its poor cycling performance caused by volume expansion during the charge-discharge process.

A summary of the mechanical properties of bone is shown in Table 2.
The mechanical properties (Table 4) of HA make it improper for load bear application.
HA is normally sintered to improve its mechanical properties.
Mechanical properties of Hydroxyapatite [6].
Hydroxyapatite synthesis Purity, morphology, stoichiometry, and microstructure of HA are critical factors affecting its cell toxicity, mechanical properties, osteoconductivity, biocompatibility and bioactivity.