Transient dynamic impact suppression of a Baja chassis using frontal and rear shock absorbers

This paper investigates the behaviour of impact loading on a Baja vehicle chassis with frontal and rear shock absorbers, using transient dynamic analysis under different assumptions of contact conditions. Using a Baja car, a transient dynamic impact is performed in ANSYS Workbench 14.0, where the maximum deformation, stress and strains are calculated over duration of the particular impact. The mathematical model of the chassis is derived based on Kelvin model in order to design the best parameters of stiffness and damping coefficient in shock absorbers to minimise the deformation of the frame with the same impact. To study the effects of shock absorber under loading on a vehicle chassis, multiple finite element simulations are performed with different methodologies. Each methodology uses a different assumption on loading and boundary conditions, which leads to different results

New homogeneous and alternating Mn(II)-azido 1D systems

Abstract Reaction of sodium azide with manganese(II) and 4-amino-1,2,4-triazol or 3-chloropyridine leads to the 1D systems [Mn(N 3 ) 2 (4-amtr) 2 ] n (1) or {[Mn(N 3 ) 2 (3-Clpy) 2 ] AE 1/2(3-Clpy)} n (2), respectively. Compound 1 crystallises in the C2/m (monoclinic) group and consists of chains of Mn(II) cations bridged by double l 1,3 -azido bridges in trans arrangement. Compound 2 crystallises in the I2/a (monoclinic) group and in this case the 1D system shows alternating double l 1,1 and l 1,3 bridges. Magnetic properties follow the expected antiferromagnetic (compound 1) and alternating ferro-antiferromagnetic (compound 2) behaviour

Source Evaluation and Trace Metal Contamination in Benthic Sediments from Equatorial Ecosystems Using Multivariate Statistical Techniques

race metals (Cd, Cr, Cu, Ni and Pb) concentrations in benthic sediments were analyzed through multi-step fractionation scheme to assess the levels and sources of contamination in estuarine, riverine and freshwater ecosystems in Niger Delta (Nigeria). The degree of contamination was assessed using the individual contamination factors (ICF) and global contamination factor (GCF). Multivariate statistical approaches including principal component analysis (PCA), cluster analysis and correlation test were employed to evaluate the interrelationships and associated sources of contamination. The spatial distribution of metal concentrations followed the pattern Pb>Cu>Cr>Cd>Ni. Ecological risk index by ICF showed significant potential mobility and bioavailability for Cu, Cu and Ni. The ICF contamination trend in the benthic sediments at all studied sites was Cu>Cr>Ni>Cd>Pb. The principal component and agglomerative clustering analyses indicate that trace metals contamination in the ecosystems was influenced by multiple pollution sources

EPR and Spectral Studies of a Molecular and Crystal Structure of Cu (3,5-dimethylpyridine)3\text{}_{3}(NO3\text{}_{3})2\text{}_{2}

X-band single crystal EPR, IR and UV-VIS data are used to deduce a molecular and crystal structure of a new compound with a chemical formula Cu(3,5-dimethylpyridine)$\text{}_{3}$(NO$\text{}_{3}$)$\text{}_{2}$. EPR shows that four magnetically inequivalent molecules exist in the crystal unit cell of C$\text{}_{4v}$ symmetry. IR spectra suggested that both monodentate and bidentate NO$\text{}_{3}$-groups exist in the crystal. A most probable Cu(II) complex geometry with d$\text{}_{x²-y²}$ ground state is a square pyramid with three nitrogens from 3,5-dimethylpyridine molecules and one oxygen from monodentate nitrato group in a basal plane and an oxygen from NO$\text{}_{3}$-group in apical position. There exists a chemical contact between complexes as it is indicated by the exchange interaction with |J| ≤ 1 cm$\text{}^{-1}$. It suggests that square pyramid complexes are arranged in polymeric chains with semi-coordination of bidentate NO$\text{}_{3}$-group to the adjacent Cu(II) ion. An extended analysis of an exchange averaging effect between EPR lines from two and four Cu(II) sites is presented with equations relating molecular and crystal g-factors

New homogeneous and alternating Mn(II)-azido 1D systems

Reaction of sodium azide with manganese(II) and 4-amino-1,2,4-triazol or 3-chloropyridine leads to the 1D systems [Mn(N-3)(2) (4-amtr)(2)](,) (1) or {[Mn(N-3)(2)(3-Clpy)(2)]center dot 1/2(3-Clpy)}(n) (2), respectively. Compound 1 crystallises in the C2/m (monoclinic) group and consists of chains of Mn(II) cations bridged by double mu(1,3)-azido bridges in trans arrangement. Compound 2 crystallises in the I2/a (monoclinic) group and in this case the 1D system shows alternating double mu(1,1) and mu(1,3) bridges. Magnetic properties follow the expected antiferromagnetic (compound 1) and alternating ferro-antiferromagnetic (compound 2) behaviour. (c) 2005 Published by Elsevier Ltd