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Here, we present a 3D printed experimental apparatus that students can use to acquire interference and diffraction quantitative data from light passing through a single or double-slit experiment. We built a linear screw stage with a multiturn potentiometer connected to its leadscrew as a position sensor. Using an Arduino, we collected light intensity data (from a photodiode mounted in the linear stage) as a function of position. The apparatus is a low-cost and compact alternative with data acquisition to optics physics laboratories.

We present an Arduino approach to collect pressure and temperature data from electronic sensors. Using a constant volume-metal-vessel immersed in a water bath and changing its temperature, we measure the pressure as a function of the temperature inside the vessel. With this apparatus, it is possible to demonstrate Gay-Lussac's law. Based on measurements of pressure and temperature we can establish the absolute Kelvin temperature scale.

João N Beato,1,2 João Esteves-Leandro,1 David Reis,3 Manuel Falcão,1,2 Vítor Rosas,1 Ângela Carneiro,1,2 Fernando Falcão Reis1,2 1Department of Ophthalmology, São João Hospital, Porto, Portugal; 2Department of Surgery and Physiology, Faculty of Medicine, University of Porto, Porto, Portugal; 3Faculty of Medicine, University of Porto, Porto, PortugalCorrespondence: João N BeatoDepartment of Ophthalmology, São João Hospital, Al Prof Hernâni Monteiro, Porto 4200-319, PortugalTel +351 225 51 2168Fax +351 225 51 3669Email joao.nuno.beato@gmail.comPurpose: To compare corneal structure and endothelial morphological features between patients with type 2 diabetes mellitus (DM) and non-diabetic patients; and determine if the DM duration, glycated hemoglobin (HbA1c) levels, and diabetic retinopathy (DR) stage affect corneal morphological properties.Patients and Methods: Sixty diabetic patients and 47 age- and sex-matched controls were enrolled in this cross-sectional study. DM group was analyzed according disease duration, HbA1c levels, and presence of retinopathy. Endothelial cell density (ECD) and morphology (average and coefficient of variation [CV] of cell size, percentage of hexagonal cells) were recorded using non-contact specular microscopy. Central corneal thickness (CCT) and corneal volume were measured by scheimpflug tomography. Univariate and multivariate linear regression analyses were performed to evaluate the relationship between demographical, clinical, and ocular variables with CCT and ECD.Results: There were no statistically significant differences in the endothelium cell density or morphology between DM and non-DM groups (p> 0.05). Also, there was no statistical difference between groups for CCT or corneal volume (p> 0.05). Multivariate linear regression analysis showed that older age (p=0.028) was significantly associated with lower ECD; CCT was found to be significantly greater in males (p< 0.001) and positively associated with corneal volume (p< 0.001).Conclusion: The present study did not find any statistically significant differences between the corneal structural and endothelial characteristics of diabetic and non-diabetic subjects; other demographical parameters, such as age and gender, seem to be more determinant for the corneal properties.Keywords: diabetes mellitus, endothelium, central corneal thickness

The author reports on a case study investigating how one nonnative English-speaking teacher (NNEST) struggled to claim professional legitimacy as a university-level ESL writing instructor. Using Vygotskian sociocultural theory (Vygotsky, 1978, 1986; Wertsch, 1985) and Bucholtz and Hall's (2005) indexicality principle, the author explores the relationship between the participant's professional self-concept and teaching practice as well as how in-service professional development experiences impacted his thinking, discourse, and action. The findings suggest that coursework and professional development addressing the native speaker myth can provide NNESTs with mediational tools through which to reimagine themselves as legitimate speakers and professionals in English Language Teaching (ELT). (Contains 1 footnote.)

We investigate experimentally and using first-principles theory the generation of phonons and the relaxation of carriers on picosecond timescales across the Brillouin zone of photo-excited Ge by inter-valley electron–phonon scattering. The phonons generated are typical of those generated in semiconductor devices, contributing to the accumulation of heat within the material. We simulate the time-evolution of phonon populations, based on first-principles band structure and electron–phonon and phonon–phonon matrix elements, and compare them to data from time-resolved x-ray diffuse scattering experiments, performed at the Linac Coherent Light Source x-ray free-electron laser facility, following photo-excitation by a 50 fs near-infrared optical pulse. We show that the intensity of the non-thermal x-ray diffuse scattering signal, which is observed to grow substantially near the L-point of the Brillouin zone over 3–5 ps, is due to phonons generated by scattering of carriers between the Δ and L valleys. These phonons have low group velocities, resulting in a heat bottleneck. With the inclusion of phonon decay through 3-phonon processes, the simulations also account for other non-thermal features observed in the x-ray diffuse scattering intensity, which are due to anharmonic phonon–phonon scattering of the phonons initially generated by electron–phonon scattering. [ABSTRACT FROM AUTHOR]

Author(s): M. F. DeCamp (corresponding author) [1]; D. A. Reis [1]; P. H. Bucksbaum [1]; B. Adams [2]; J. M. Caraher [1]; R. Clarke [1]; C. W. S. Conover [3]; [...]

RMn2Si2 (R = Tm, Dy, and Tb) and HoCoSi alloys, presenting multiple magnetic phase transitions (except for TmMn2Si2 and HoCoSi) and large magnetocaloric effect (MCE), were physically mixed to produce a composite magnetic refrigerant. The used concentration of each alloy was 0.1(TmMn2Si2) + 0.35(DyMn2Si2) + 0.4(TbMn2Si2) + 0.15(HoCoSi). X-ray diffraction and magnetization measurements were used to investigate the crystallographic and magnetic properties of the samples. The results indicate the maximum values of magnetic entropy change (− ∆ S M max ) of ~ 4.6 J/kg K under magnetic field change (ΔH) of 50 kOe. A large table-like MCE was observed for the composite sample. The full width at half maximum of ΔSM peak (δTFWHM) values reaches ~ 60.4 K (ΔH = 20 kOe) and ~ 67.2 K (ΔH = 50 kOe), which correspond to a respective ΔSM peak broadening of 230% and 180% for the composite sample compared with each compound studied individually. Such property is important for a material to operate in an ideal Ericsson cycle. [ABSTRACT FROM AUTHOR]

In this study, plasma treatment was performed to increase the surface hardness, followed by the deposition of MoS2-TiN multilayer films by magnetron sputtering to reduce friction and facilitate sliding contact. The tribological test was performed with a tribometer (cylinder-disc type) developed exclusively to simulate the behavior of these components under pressure and movement conditions similar to those present in the common rail injection system (CRIS). The results obtained in this work showed a considerable increase in surface hardness due to the formation of iron nitrides caused by the plasma treatment, which slightly decreased by solid lubrication coating (MoS2). The increase in cycles in the tribological test causes a reduction in surface roughness due to the softness of the MoS2 layers by plastic deformation. The combination of plasma treatment and MoS2-TiN multilayer films contributed to the decrease in mass loss and better performance of the studied components. [ABSTRACT FROM AUTHOR]