Owing to better mechanical properties and shape memory effect, the NiTi composites fabricated by powder metallurgy are suitable for biomedical implants. However, the excessive porosity and formation of micro-cracks are the major issues related to the NiTi composite. This work focused on developing crack-free dense NiTi composites by newly developed uni-axial compaction die. The work includes the design and manufacturing of uni-axial compaction die. The die was tested by SOLIDWORKS software in a simulated environment. Further, composite samples were successfully fabricated without circumferential micro-cracks at 1910.82 MPa compaction pressure. The effects of compaction pressure on microstructural, densification, and mechanical behavior of NiTi composites were also analyzed. Microstructural characterization shows that the Ni-rich phase increased and the Ti-rich phase decreased with the increase of compaction pressure. The porosity reduces from 17.04 to 8.75% by increasing the compaction pressure from 1273.88 to 1910.82 MPa, and a maximum density of 5.50 g.cm–3 was obtained. The NiTi150 composite has similar Young’s modulus, and compressive strength (6.93 GPa and 94.36 MPa) compared to cortical and cancellous bone. The high compaction pressure also increases the micro-hardness of NiTi composite up to 453.8 HV0.5.

Repeated soil amendment with industrial waste can affect the accumulation of chemical elements, mainly heavy metals, in plants. We therefore evaluated the accumulation of Cr, Cd, Ni, and Pb in cowpea (Vigna unguiculata [L.] Walp.) shoots and grains in soil amended for three consecutive years with tannery sludge compost (TSC). Tannery sludge compost was applied annually starting in 2009 at 0, 2.5, 5, 10, and 20 t ha-1 and cowpea was sown. At 40 and 60 d after cowpea sowing, the accumulation of Cr, Cd, Pb, and Ni was evaluated in the shoots and grains, respectively. The experiment used completely randomized design with four replicates and data were subjected to ANOVA and F-test (5%). Only Cr accumulation was significant (P < 0.05) in the cowpea shoots after 3 yr of TSC amendment; accumulation increased as TSC rates were applied. However, there was no significant Cr, Cd, Ni, and Pb accumulation in grains. After 3 yr of consecutive TSC soil amendments, Cr accumulated in the shoots, but it was not translocated to the grains.

A geração de resíduos de curtume está aumentando a cada ano e um método adequado para o manejo do resíduo de curtume é necessário para diminuir o problema ambiental. A compostagem é reconhecido como um método adequado para a reciclagem do lodo. O objetivo do trabalho foi investigar o efeito da aplicação de composto de lodo de curtume (CLC) sobre o crescimento, nodulação e acumulação de nitrogênio do feijão-caupi. Solos arenoso e argiloso foram adubados com CLC em doses de 0, 7,5, 15, 30 e 60 t ha-1. O comprimento da parte aérea do feijão-caupi foi maior, aos 45 dias após a emergência das plantas (DAE), no solo com aplicação de CLC do que no solo sem aplicação. No solo arenoso, a massa dos nódulos, aos 45 DAE, aumentou com a aplicação do CLC. No solo argiloso, aos 45 DAE, em doses superiores a 7,5 t ha-1, houve um decréscimo na massa nodular quando comparado ao solo sem aplicação. A aplicação do CLC aumentou a acumulação de N nas plantas de feijão-caupi. Os resultados sugerem que o feijão-caupi responde diferentemente ao CLC sendo dependente da dose de aplicação e do tipo de solo.

Tannery wastes generation is increasing every year and a suitable method for tannery sludge management is necessary in order to decrease this environmental problem. The composting is recognized as a suitable method for sludge recycling.. The effect of tannery sludge compost (TSC) rates on growth, nodulation and N fixation of cowpea was investigated. Sandy and clayey soils were amended with TSC at rates of 0, 7.5, 15, 30, and 60 t ha-1. The shoot dry weight of cowpea plants 45 days after emergence (DAE) was greater in the TSC-amended than in the unamended soil. In the sandy soil, nodule dry weight increased with TSC application 45 DAE. In the clayey soil, 45 DAE, nodule dry weight decreased with TSC amendment levels greater than 7.5 t ha-1 compared to the unamended control. The application of TSC increased N accumulation in the cowpea plants. The results suggest that cowpea responds differently to TSC depending on the amendment rate and initial soil type.