Internal stresses in steel plate generated by shape memory alloy inserts

Neutron strain scanning was employed to investigate the internal stress fields in steel plate coupons with embedded prestrained superelastic NiTi shape memory alloy inserts. Strain fields in steel were evaluated at T = 21 °C and 130 °C on virgin coupons as well as on mechanically and thermally fatigued coupons. Internal stress fields were evaluated by direct calculation of principal stress components from the experimentally measured lattice strains as well as by employing an inverse finite element modeling approach. It is shown that if the NiTi inserts are embedded into the elastic steel matrix following a carefully designed technological procedure, the internal stress fields vary with temperature in a reproducible and predictable way. It is estimated that this mechanism of internal stress generation can be safely applied in the temperature range from −20 °C to 150 °C and is relatively resistant to thermal and mechanical fatigue. The predictability and fatigue endurance of the mechanism are of essential importance for the development of future smart metal matrix composites or smart structures with embedded shape memory alloy components

Aplikasi Citra Satelit Landsat 8 Untuk Identifikasi Daerah Prospek Panas Bumi Daerah Songgoriti Batu Dan Sekitarnya

Dalam menentukan daerah prospek panas bumi, pemetaan permukaan diperlukan untuk menentukan titik atau area prospek yang dapat dikaji bawah permukaannya. Pemetaan permukaan bumi dapat dilakukan menggunakan citra satelit landsat 8. Penelitian ini dilakukan untuk memetakan struktur , temperatur permukaan tanah dan batuan permukaan. Hasil yang didapatkan dikorelasikan dengan geologi. Data citra yang digunakan pada penelitian ini adalah citra satelit landsat 8 dengan band 4, band 5, band 7 dan band 11. Untuk memperoleh informasi struktur bawah permukaan dilakukan komposit pada band 4, band 5, band 7. Untuk menentukan temperatur permukaan digunakan band 11 yang dikoreksi atmosfer terlebih dahulu untuk menghilangkan pengaruh atmosfer dalam wilayah termal. Untuk menentukan titik batuan teralterasi maka dilakukan komposit band 7, band 4, band 2. Hasil yang didapatkan adalah struktur bawah permukaan, temperature permukaan dan batuan permukaan tanah

Residual Strain Dependence on Matrix Structure in RHQ-Nb3Al Wires by Neutron Diffraction Measurement

We prepared three types of non-Cu RHQ-Nb3Al wire samples with different matrix structures: an all-Ta matrix,a composite matrix of Nb and Ta with a Ta inter filament, and an all-Nb matrix. Neutron diffraction patterns of the wire samples were measured at room temperature in J-PARC "TAKUMI". To obtain residual strains of materials, we estimated lattice constant a by multi-peak analysis in the wire. Powder sample of each wire was measured, where the powder was considered to be strain-free. The grain size of all the powder samples was below 0.02 mm. For wire sample with the all-Nb matrix, we also obtained lattice spacing d by a single-peak analysis. Residual strains of Nb3Al filament were estimated from the two analysis results and were compared. Result, residual strains obtained from the multi-peak analysis showed a good accuracy with small standard deviation. The multi-peak analysis results for the residual strains of Nb3Al filament in the three samples were all tensile residual strain in the axial direction, they are 0.12%, 0.12%, and 0.05% for the all-Ta matrix, the composite matrix, and the all-Nb matrix, respectively. Difference in the residual strain of Nb3Al filament between the composite and all-Nb matrix samples indicates that type of inter-filament materials show a great effect on the residual strain. In this paper, we report the method of measurement, method of analysis, and results for residual strain in the tree types of non-Cu RHO-Nb3Al wires.Comment: 7 pages, 8 figure

Case Report: Sublingual Microcirculatory Alterations in a Covid-19 Patient With Subcutaneous Emphysema, Venous Thrombosis, and Pneumomediastinum

The Corona virus disease 2019 (Covid-19) has brought a wide range of challenges in intensive care medicine. Understanding of the pathophysiology of Covid-19 relies on interpreting of its impact on the vascular, particularly microcirculatory system. Herein we report on the first use of the latest generation hand-held vital microscope to evaluate the sublingual microcirculation in a Covid-19 patient with subcutaneous emphysema, venous thrombosis and pneumomediastinum. Remarkably, microcirculatory parameters of the patient were increased during the exacerbation period, which is not a usual finding in critically ill patients mostly presenting with a loss of hemodynamic coherence. In contrast, recovery from the disease led to a subsequent amelioration of these parameters. This report clearly shows the importance of microcirculatory monitoring for evaluating the course and the adequacy of therapy in Covid-19 patients

Creating spaces: testimonio, impossible knowledge, and academe

Postprint upload.This article examines what it means to engage seriously with speech and writing events, such as testimonio, articulated by people whose theoretical base lies primarily in experience outside the walls of academe. I argue that we dismiss such unfamiliar scholarship to the detriment of all involved. If we are truly committed to learning, then we must expose ourselves to language forms and cultural norms that are different from those with which we are familiar. We must learn from them how to acknowledge the limits of our analysis and how to find “impossible knowledge” in unaccustomed places

Developing an interatomic potential for martensitic phase transformations in zirconium by machine learning

Interatomic potentials: predicting phase transformations in zirconium Machine learning leads to a new interatomic potential for zirconium that can predict phase transformations. A team led by Hongxian Zong at Xi’an Jiaotong University, China, and Turab Lookman at Los Alamos National Laboratory, U.S.A, used a Gaussian-type machine learning approach to produce an interatomic potential that predicted phase transformations in zirconium. They expressed each atomic energy contribution via changes in the local atomic environment, such as bond length, shape, and volume. The resulting machine-learning potential successfully described pure zirconium’s physical properties. When used in molecular dynamics simulations, it predicted a zirconium phase diagram as a function of both temperature and pressure that agreed well with previous experiments and simulations. Developing learnt interatomic potentials in phase-transforming systems could help us better simulate complex systems

Laterally focused attention modulates asymmetric coupling in rhythmic interlimb coordination.

Peters (J Motor Behav 21:151-155, 1989; Interlimb coordination: neural, dynamical and cognitive constraints, Academic, Orlando, pp 595-615, 1994) suggested that expressions of handedness in bimanual coordination may be reflections of an inherent attentional bias. Indeed, previous results indicated that focusing attention on one of the limbs affected the relative phasing between the limbs in a manner comparable to the effects of hand dominance. The present study extended the comparison between the effects of attentional focus and handedness by testing their impact on the interactions between the limbs. Both left-handed and right-handed participants performed rhythmic bimanual coordination tasks (in-phase and antiphase coordination), while directing attention to either limb. Using brief mechanical perturbations, the degree to which the limbs were influenced by each other was determined. The results revealed that the non-dominant limb was more strongly affected by the dominant limb than vice versa and that, in line with Peters' proposition, this handedness-related asymmetry in coupling strength was reduced when attention was focused on the non-dominant limb, thereby highlighting the potential relation between inherent (handedness-related) asymmetries and voluntary attentional asymmetries. In contrast to previous findings, the (commonly observed) phase lead of the dominant limb was attenuated (rather than accrued) when attention was focused on this limb. This unexpected result was explained in terms of the observed attention-related difference in amplitude between the limbs. © 2006 Springer-Verlag