Direct Measurement of the Magnetocaloric Effect through Time-Dependent Magnetometry

The magnetocaloric effect of a given material is typically assessed through indirect estimates of the isothermal magnetic entropy change, ΔSM. While estimating the adiabatic temperature difference, ΔTad, is more relevant from the standpoint of refrigeration device engineering, this requires specialized experimental setups. We here present an approach to directly measure ΔTad through time-dependent magnetometry in a commercial superconducting quantum interference device (SQUID) device. We use as reference material gadolinium under a 20-kOe field change, and compare our results with those of the literature. Under nonadiabatic experimental conditions, a remarkably similar ΔTad(T) curve profile is obtained; however, its peak amplitude is underestimated. With a simple compensation methodology we are able to further approximate the profile of the ΔTad(T) curve obtaining the peak amplitude, the maximizing temperature, and the FWHM within relative errors of -4%, -0.7%, and 11%, respectively. Our reported approach makes the measurement of both ΔSM(T) and ΔTad(T) possible with a single instrument, enabling accelerated progress towards new, competitive, and industry-ready materials.publishe

Constructed response or multiple-choice questions for assessing declarative programming knowledge? That is the question!

Aim/Purpose This paper presents a data mining approach for analyzing responses to advanced declarative programming questions. The goal of this research is to find a model that can explain the results obtained by students when they perform exams with Constructed Response questions and with equivalent Multiple-Choice Questions. Background The assessment of acquired knowledge is a fundamental role in the teachinglearning process. It helps to identify the factors that can contribute to the teacher in the developing of pedagogical methods and evaluation tools and it also contributes to the self-regulation process of learning. However, better format of questions to assess declarative programming knowledge is still a subject of ongoing debate. While some research advocates the use of constructed responses, others emphasize the potential of multiple-choice questions. Methodology A sensitivity analysis was applied to extract useful knowledge from the relevance of the characteristics (i.e., the input variables) used for the data mining process to compute the score. Contribution Such knowledge helps the teachers to decide which format they must consider with respect to the objectives and expected students results. Findings The results shown a set of factors that influence the discrepancy between answers in both formats. Recommendationsfor Practitioners Teachers can make an informed decision about whether to choose multiplechoice questions or constructed-response taking into account the results of this study. Recommendations for Researchers In this study a block of exams with CR questions is verified to complement the area of learning, returning greater performance in the evaluation of students and improving the teaching-learning process. Impact on Society The results of this research confirm the findings of several other researchers that the use of ICT and the application of MCQ is an added value in the evaluation process. In most cases the student is more likely to succeed with MCQ, however if the teacher prefers to evaluate with CR other research approaches are needed. Future Research Future research must include other question formats.info:eu-repo/semantics/publishedVersio

Dois Casos de Quérion por Trichophyton Mentagrophytes

Introdução: O Quérion é uma forma rara e infl amatória de tinea capitis causada por fungos dermatófi tos. O diagnóstico é difi cultado pela demora no exame cultural e possibilidade de várias etiologias no diagnóstico diferencial. O tratamento é prolongado e implica o recurso a antifúngicos sistémicos. Novos fármacos têm sido considerados após a descontinuação da griseofulvina em Portugal. Casos clínicos: Apresentamos duas crianças com lesões dolorosas do couro cabeludo com reação infl amatória exuberante, exsudativa e alopécia local acompanhadas de febre. O exame bacteriológico foi negativo e o micológico revelou Trichophyton mentagrophytes. Foram medicados com fl ucloxacilina endovenosa, antifúngicos orais (griseofulvina e itraconazol), corticoide e antifúngico tópicos. A resposta foi favorável com evolução lenta para a cura com área de alopécia residual. Conclusão: Estes casos destacam -se pela sua raridade e ilustram a exuberância das manifestações clínicas desta entidade. O diagnóstico precoce, a identificação e tratamento da fonte de contágio e as medidas de higiene e vigilância sanitária são primordiais para o controlo da infecção

On the mutual effect of ion temperature gradient instabilities and impurity peaking in the reversed field pinch

The presence of impurities is considered in gyrokinetic calculations of ion temperature gradient (ITG) instabilities and turbulence in the reversed field pinch device RFX-mod. This device usually exhibits hollow Carbon/Oxygen profiles, peaked in the outer core region. We describe the role of the impurities in ITG mode destabilization, and analyze whether ITG turbulence is compatible with their experimental gradients.Comment: 19 pages, 9 figures, accepted for publication in Plasma Phys. Control. Fusio

Biometria de frutos em um plantio de açaí em Porto Velho, Rondônia.

O objetivo deste trabalho foi realizar a biometria de frutos em um plantio de açaí em Porto Velho, Rondônia

Produção inicial de frutos num plantio de açaí em Porto Velho, Rondônia.

O objetivo deste estudo foi avaliar a produção inicial de frutos entre de um plantio de açaí BRS Pará em Rondônia

On the nature of the (de)coupling of the magnetostructural transition in Er5_5Si4_4

In this report, a successful thermodynamical model was employed to understand the structural transition in Er$_5$Si$_4$, able to explain the decoupling of the magnetic and structural transition. This was achieved by the DFT calculations which were used to determine the energy differences at 0 K, using a LSDA+U approximation. It was found that the M structure as the stable phase at low temperatures as verified experimentally with a $\Delta F_0 = -$0.262 eV. Finally, it was achieved a variation of Seebeck coefficient ($\sim$ 6 $\mu$V) at the structural transition which allow to conclude that the electronic entropy variation is negligible in the transition.Comment: 17 pages, 3 figures, 1 tabl