Participatory forest management in Burkina Faso: Members’ perception of performance

This study examines variations in the performance of participatory forest management programs among four forest management groups (FMGs) in southern Burkina Faso, and assesses the factors that influence their members’ perceptions of performance through a household survey of 216 members. Variations in performance scores among the FMGs were analyzed through multivariate analysis of variance while multinomial regression analysis was used to identify factors that influence their perception of the performance. The results reveal significant differences in performance scores among FMGs. Members of some FMGs perceived that the participatory forest management program enabled them to get benefits from the sale of fuelwood while performance scores in the forest conservation and decision-making processes is generally poor. The score for economic performance of FMGs in turn was related to better access to roads and markets. Group size tended to enhance economic performance via its strong influence on annual fuelwood harvest, while the resource base appeared to be inconsequential. Members of the forest management groups perceived that large group size and group heterogeneity, particularly in terms of ethnicity, as well as knowledge and awareness of problems related to the forest environment have no influence on the performance of their respective groups. For rural communities to have a favorable disposition toward sustainable forest management, differences in member understanding of collective actions and their impact before and during the implementation of participatory forest management programs should be considered

Solid state formation of Ti4AlN3 in cathodic arc deposited (Ti1-xAlx)N-y alloys

Reactive cathodic arc deposition was used to grow substoichiometric solid solution cubic c-(Ti1-xAlx)N-y thin films. The films were removed from the substrate and then heated in an argon environment to 1400 degrees C. Via solid state reactions, formation of MAX phase Ti4AlN3 was obtained. Additional phases such as Ti2AlN, c-TiN, w-AIN, Al5Ti2 and Al3Ti were also present during the solid state reaction. Ti4AlN3 formation was observed in samples with an Al metal fraction x amp;lt; 0.63 and a nitrogen content 0.4 amp;lt; y amp;lt; 0.6. Regardless of the initial composition, formation of Ti4AlN3 started in Ti2AlN crystal plates in the temperature range between 1200 and 1400 degrees C. Accompanying the onset of Ti4AlN3 was the presence of an intermediate structure identified as Ti6Al2N4, consisting of alternating layers of intergrown Ti2AlN and Ti4AlN3 phases with a half-unit-cell stacking. We suggest that the formation of Ti4AlN3 occurred via intercalation of aluminum and nitrogen along the basal plane accompanied by a simultaneous detwinning process. In addition we propose that this formation mechanism can be used to obtain MAX phases of high n order. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.Funding Agencies|European Unions Erasmus Mundus doctoral program DocMASE; Swedish Research Council [621-2012-4401]; Swedish government strategic research area grant AFM SFO MatLiU [2009-00971]; VINNOVA (M - Era.net project MC2) [2013-02355]; European Research Council under the European Communitys Seventh Framework Program (FP) [335383]; DFG; federal state government of Saarland [INST 256/298-1 FUGG, INST 256/431-1 FUGG]; European Regional Development Fund [AME-Lab C/4-EFRE-13/2009/Br]</p

Eutectic modification by ternary compound cluster formation in Al-Si alloys

Abstract Al-alloys with Si as the main alloying element constitute the vast majority of Al castings used commercially today. The eutectic Si microstructure in these alloys can be modified from plate-like to coral-like by the addition of a small amount of a third element to improve ductility and toughness. In this investigation the effects of Eu and Yb are studied and their influence on the microstructure is compared to further understand this modification. The two elements impact the alloy differently, where Eu modifies Si into a coral-like structure while Yb does not. Atom probe tomography shows that Eu is present within the Si phase in the form of ternary compound Al2Si2Eu clusters, while Yb is absent in the Si phase. This indicates that the presence of ternary compound clusters within Si is a necessary condition for the formation of a coral-like structure. A crystallographic orientation relationship between Si and the Al2Si2Eu phase was found, where the following plane normals are parallel: 011Si//0001Al2Si2Eu, 111Si//6$$\bar{7}$$ 7¯ 10Al2Si2Eu and 011Si//6$$\bar{7}$$ 7¯ 10Al2Si2Eu. No crystallographic relationship was found between Si and Al2Si2Yb. The heterogeneous formation of coherent Al2Si2Eu clusters inside the Si-phase is suggested to trigger the modification of the microstructure

Enhanced thermal stability and mechanical properties of nitrogen deficient titanium aluminum nitride (Ti0.54Al0.46Ny) thin films by tuning the applied negative bias voltage

Aspects on the phase stability and mechanical properties of nitrogen deficient (Ti0.54Al0.46)N-y alloys were investigated. Solid solution alloys of (Ti,Al)N were grown by cathodic arc deposition. The kinetic energy of the impinging ions was altered by varying the substrate bias voltage from -30V to -80 V. Films deposited with a high bias value of -80V showed larger lattice parameter, finer columnar structure, and higher compressive residual stress resulting in higher hardness than films biased at -30V when comparing their as-deposited states. At elevated temperatures, the presence of nitrogen vacancies and point defects (anti-sites and self-interstitials generated by the ion-bombardment during coating deposition) in (Ti0.54Al0.46)N-0.87 influence the driving force for phase separation. Highly biased nitrogen deficient films have point defects with higher stability during annealing, which cause a delay of the release of the stored lattice strain energy and then accelerates the decomposition tendencies to thermodynamically stable c-TiN and w-AlN. Low biased nitrogen deficient films have retarded phase transformation to w-AlN, which results in the prolongment of age hardening effect up to 1100 degrees C, i.e., the highest reported temperature for Ti-Al-N material system. Our study points out the role of vacancies and point defects in engineering thin films with enhanced thermal stability and mechanical properties for high temperature hard coating applications. Published by AIP Publishing.Funding Agencies|European Unions Erasmus Mundus doctoral program in Materials Science and Engineering (DocMASE); Swedish Research Council [621-2012-4401]; Swedish government strategic research area grant AFM - SFO MatLiU [2009-00971]; VINNOVA [2013-02355]; DFG; federal state government of Saarland [INST 256/298-1 FUGG]; European Regional Development Fund [AME-Lab C/4-EFRE-13/2009/Br]</p