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1.
J Sci Educ Technol ; 31(3): 322-339, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35106048

RESUMO

Augmented reality (AR) has the capacity to afford a virtual experience that obviates the reliance on using two-dimensional representations of 3D molecules for teaching stereochemistry to undergraduate students. Using a combination of quantitative instruments and qualitative surveys/interviews, this study explored the relationships between students' attitudes, perceived cognitive load, spatial ability, and academic performance when engaging in an asynchronous online stereochemistry activity. Our activity was designed using elements of game-based learning, and integrated AR technologies. The control group was provided with a copy of our activity that used two-dimensional drawings, whereas the AR group completed an activity using the AR technologies. For this cohort of students, results indicated significant improvement in academic performance in both the control and AR groups. The introduction of AR technologies did not result in the AR group outperforming the control group. Participants from both groups displayed significant improvements in spatial ability throughout the research period. Further, a moderate correlation (r s = 0.416) between students' spatial ability and academic performance was found. No significant intergroup differences in the perceived cognitive loads of students were observed. A significant difference was observed on one item of the Intellectual Accessibility subscale of the ASCI (V2), Complicated-Simple. We found no correlation for student attitude or cognitive load with academic performance. The findings of this study provide insights for future AR-related studies to explore the role of spatial ability, student attitude, and cognitive load in learning performance. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10956-022-09957-0.

2.
Chimia (Aarau) ; 75(1): 18-26, 2021 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-33637142

RESUMO

The chemistry foundation year at the University of East Anglia is a diverse cohort with a wide range of prior educational experience and confidence levels. A flexible learning program combining extensive online materials intended for asynchronous study and face to face peer instruction is provided. Study is divided into weekly topics. Students are directed to take a short introductory quiz at the beginning of the week, feedback on which allows them to tailor the extent of asynchronous learning to their own needs. All students attend a highly interactive synchronous teaching session which utilises active learning to develop their conceptual understanding. The week concludes with a reflective formative test. Measures of student activity on the online platform and audience response technology in the lecture theatre provide a quantitative picture of engagement with tailored blended learning, while semi-structured interviews provide qualitative insight into the student perception.

3.
J Acoust Soc Am ; 136(4): 1942-50, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25324093

RESUMO

Studies have been made of the normal modes of a 20.7 cm diameter steel gamelan gong. A finite-element model has been constructed and its predictions for normal modes compared with experimental results obtained using electronic speckle pattern interferometry. Agreement was reasonable in view of the lack of precision in the manufacture of the instrument. The results agree with expectations for an axially symmetric system subject to small symmetry breaking. The extent to which the results obey Chladni's law is discussed. Comparison with vibrational and acoustical spectra enabled the identification of the small number of modes responsible for the sound output when played normally. Evidence of non-linear behavior was found, mainly in the form of subharmonics of true modes. Experiments using scanning laser Doppler vibrometry gave satisfactory agreement with the other methods.

4.
J Acoust Soc Am ; 131(3): 2288-94, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22423723

RESUMO

The geometrical structure of the Indian elephant bell is presented and the requirements on its normal modes from group representation theory are described. These are in good agreement with the results of a finite-element model (FEM) for a specific 16-tine case. The spectrum consists of a sequence of families of modes lying on saturation curves, completely different from those of conventional bells. Physical explanations for the occurrence of these families are presented in terms of the tines behaving as a closed loop of coupled cantilevers with constraints from the dome. Each family is found to consist of modes in one of two specific sequences of symmetry types. Experimental measurements of the modes of this same 16-tine bell, using electronic speckle pattern interferometry (ESPI), have been made and are compared with the FEM predictions. Although the interpretation of the interferograms is difficult in all but the simpler cases, agreement in terms of frequencies is surprisingly good for the first few family sequences. The ESPI study also showed up numerous harmonics and subharmonics of true normal modes, showing the system to be rather non-linear and making comparisons with the FEM results tricky.

5.
J Acoust Soc Am ; 130(5): 2746-55, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22087903

RESUMO

The results of numerical modeling of sonic crystals with resonant array elements are reported. The investigated resonant elements include plain slotted cylinders as well as their various combinations, in particular, Russian doll or Matryoshka configurations. The acoustic band structure and transmission characteristics of such systems have been computed with the use of finite element methods. The general concept of a locally resonant sonic crystal is proposed that utilizes acoustic resonances to form additional band gaps that are decoupled from Bragg gaps. An existence of a separate attenuation mechanism associated with the resonant elements that increases performance in the lower frequency regime has been identified. The results show a formation of broad band gaps positioned significantly below the first Bragg frequency. For low frequency broadband attenuation, a most optimal configuration is the Matryoshka sonic crystal, where each scattering unit is composed of multiple concentric slotted cylinders. This system forms numerous gaps in the lower frequency regime, below Bragg bands, while maintaining a reduced crystal size viable for noise barrier technology. The finding opens alternative perspectives for the construction of sound barriers in the low frequency range usually inaccessible by traditional means including conventional sonic crystals.


Assuntos
Acústica/instrumentação , Som , Simulação por Computador , Cristalização , Desenho de Equipamento , Análise de Elementos Finitos , Modelos Teóricos , Movimento (Física) , Ruído/prevenção & controle , Análise Numérica Assistida por Computador , Pressão , Vibração
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