Recent advances in the development of aerospace materials

Pollution assessment of heavy metals in soils of India and ecological risk assessment: A state-of-the-art.

Land degradation is a global issue receiving much attention currently. In order to objectively reveal the research situation of land degradation, bibliometrix and biblioshiny software packages have been used to conduct data mining and quantitative analysis on research papers in the fields of land degradation during 1990–2019 (data update time was 8 April 2019) in the Web of Science core collection database. The results show that: (1) during the past 20 years, the number of papers on land degradation has increased. According to the number of articles, it is divided into four stages: a low-production exploration period, a developmental sprout period, expansion of the promotion period, and a high-yield active period. (2) Land-degradation research covers 93 countries or regions. The top five countries in terms of research volume are China, the United States, the United Kingdom, Germany, and Australia. China, the United States, and the United Kingdom are the most important countries for international cooperation in the field of land degradation. However, cooperation between countries is not very close overall. (3) Land degradation, degradation, desertification, remote sensing, soil erosion, and soil degradation are high-frequency keywords in the field of land degradation in recent years. (4) The research hotspots in the field of land degradation mainly focus on research directions such as restoration and reconstruction of land degradation, and sustainable management of land resources. (5) The themes of various periods in the field of land degradation are diversified, and the evolutionary relationship is complex. There are 15 evolutionary paths with regard to dynamic monitoring of land degradation, environmental governance of land degradation, and responses of land degradation to land-use change. Finally, the paper concludes that the research directions on land degradation in future include the process, mechanism, and effect of land degradation, the application of new technologies, new monitoring methods for land degradation, theory enhancement, methods and models of ecological restoration, reconstruction of degraded land, multidisciplinary integrated system research, constructing a policy guarantee system for the reconstruction of degraded land, and strengthening research on land resource engineering.

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A Bibliometric Analysis on Land Degradation: Current Status, Development, and Future Directions

In recent year's aluminum and aluminum alloys are widely used in automotive industries. These are light weight (density of about 2.7g/cc),having good malleability and formability, high corrosion resistance and high electrical and thermal conductivity. High machinability and workability of aluminum alloys are prone to porosity due to gases dissolved during melting processes. However, in the engineering application pure aluminum and its alloys still have some problems such as relatively low strength, unstable mechanical properties. The microstructure can be modified and mechanical properties can be improved by alloying, cold working and heat treatment in this regards, this paper reports the influences of some alloying elements on the microstructures and mechanical properties of Aluminum alloys and aluminum alloy composites.

http://www.ijsrp.org/research_paper_jun2012/ijsrp-June-2012-10.pdf

Reviews on the Influences of Alloying elements on the Microstructure and Mechanical Properties of Aluminum Alloys and Aluminum Alloy Composites

Digital mapping of soil properties using multiple machine learning in a semi-arid region, central Iran

Assessment and Monitoring of Soil Degradation during Land Use Change Using Multivariate Analysis

In this investigation, the effect of Al–5Zr and Al–5Ti–1B grain refiners and cooling rate on an Al–Zn–Mg–Cu alloy with high amount of zinc was studied. Microstructural examinations were conducted by X-ray diffractometry, optical and scanning electron microscopy coupled with energy dispersive spectrometry. Constituents were identified as α(Al), η-MgZn2, T-Al2Mg3Zn3 and S-Al2CuMg phases. The optimum level of Zr as Al–5Zr and Ti as Al–5Ti–1B grain refiners was found to be 0.3 and 0.05 wt.%, respectively. Increasing cooling rate through reduced sections, decreases grain size and dendrite arm spacing, but Ti-refined specimens showed lowest sensitivity to cooling rate. After homogenization at 455 °C for 24 h, constituents were α(Al) and Zn-free S-phase. T6 heat treatment including quenching to room temperature and aging at 120 °C for 24 h were employed to reach to maximum strength. Increasing cooling rate results in higher strength and Ti-refined specimens showed highest tensile strength and elongation values. Data scatter of tensile tests attributed to casting defects and fractography studies revealed a predominantly intergranular brittle fracture.

The effect of Ti and Zr elements and cooling rate on the microstructure and tensile properties of a new developed super high-strength aluminum alloy

The microstructure, hardness and tensile properties of a new super high strength aluminum alloy with Zr addition

Effects of Al-5Ti-1B and Al-5Zr master alloys on the structure, hardness and tensile properties of a highly alloyed aluminum alloy

In this study, an Al/Al-Zn-Mg-Cu laminated composite was successfully produced for the first time by using Al 1050 and a super high strength 7xxx aluminum alloy sheets through accumulative roll bonding (ARB) process at an elevated temperature. In this process after sandwich preparation, in per cycle applied 50% reduction in total thickness. The microstructural investigations after different ARB cycles showed that ARB process led to a fine distribution of the secondary phases and also a relatively remarkable decrease in their particle size in the Al-Zn-Mg-Cu (AZMC) layer. Furthermore, it was observed that all the layers of the ARBed sheets remained relatively straight without any necking or fracture during the plastic deformation in the first two cycles. Also, the macrostructure showed elongated and ultra-fine grains after the fourth cycle in the AZMC and pure Al (PA) layers, respectively. In addition, computer simulation demonstrated strain and stress gradients in the ARBed sheet. The mechanical examinations displayed a significant improvement of elongation and ultimate tensile strength (UTS) values and also microhardness values of the AZMC layer with increasing the ARB cycles. However, the microhardness variations were so slight (

Soheila Ebrahimi

Papers

Assessment and Monitoring of Soil Degradation during Land Use Change Using Multivariate Analysis

The effect of Ti and Zr elements and cooling rate on the microstructure and tensile properties of a new developed super high-strength aluminum alloy

The microstructure, hardness and tensile properties of a new super high strength aluminum alloy with Zr addition

Effects of Al-5Ti-1B and Al-5Zr master alloys on the structure, hardness and tensile properties of a highly alloyed aluminum alloy

Investigation on microstructure and mechanical properties of Al/Al-Zn-Mg–Cu laminated composite fabricated by accumulative roll bonding (ARB) process