title: Determining acoustical directionality in an impedance tube using multiple fixed microphones

authors: Pennington, Kyle

abstract: Acoustic impedance of a port or object is a valuable piece of knowledge describing how well sound is transmitted or reflected. The commonly used slotted-line method is labourious and time consuming, requiring manual movement to find the maxima and minima at each frequency. This paper outlines a technique to computationally determine the magnitude and phase of the constituent travelling waves from the standing plane sound wave measurements in an impedance tube. Measured magnitude and phase data from multiple fixed microphones carefully spaced along the length of the impedance tube is numerically fitted to incident and reflected wave models, which can then be used to calculate the complex acoustic impedance at each frequency of interest.

text: Determining acoustical directionality in an impedance tube using multiple fixed microphones Acoustic impedance of a port or object is a valuable piece of knowledge describing how well sound is transmitted or reflected. The commonly used slotted-line method is labourious and time consuming, requiring manual movement to find the maxima and minima at each frequency. This paper outlines a technique to computationally determine the magnitude and phase of the constituent travelling waves from the standing plane sound wave measurements in an impedance tube. Measured magnitude and phase data from multiple fixed microphones carefully spaced along the length of the impedance tube is numerically fitted to incident and reflected wave models, which can then be used to calculate the complex acoustic impedance at each frequency of interest.

year: 2011

title: Evaluation of the mechanical properties of powder metallurgy Ti-6Al-7Nb alloy

authors: Bolzoni, Leandro

subjects: Titanium alloy

abstract: Titanium and its alloys are common biomedical materials owing to their combination of mechanical properties, corrosion resistance and biocompatibility. Powder metallurgy (PM) techniques can be used to fabricate biomaterials with tailored properties because changing the processing parameters, such as the sintering temperature, products with different level of porosity and mechanical performances can be obtained. This study addresses the production of the biomedical Ti-6Al-7Nb alloy by means of the master alloy addition variant of the PM blending elemental approach. The sintering parameters investigated guarantee that the complete diffusion of the alloying elements and the homogenization of the microstructure is achieved. The sintering of the Ti-6Al-7Nb alloy induces a total shrinkage between 7.4% and 10.7% and the level of porosity decreases from 6.2% to 4.7% with the increment of the sintering temperature. Vickers hardness (280–300 HV30) and tensile properties (different combination of strength and elongation around 900 MPa and 3%) are achieved.

text: Evaluation of the mechanical properties of powder metallurgy Ti-6Al-7Nb alloy Titanium and its alloys are common biomedical materials owing to their combination of mechanical properties, corrosion resistance and biocompatibility. Powder metallurgy (PM) techniques can be used to fabricate biomaterials with tailored properties because changing the processing parameters, such as the sintering temperature, products with different level of porosity and mechanical performances can be obtained. This study addresses the production of the biomedical Ti-6Al-7Nb alloy by means of the master alloy addition variant of the PM blending elemental approach. The sintering parameters investigated guarantee that the complete diffusion of the alloying elements and the homogenization of the microstructure is achieved. The sintering of the Ti-6Al-7Nb alloy induces a total shrinkage between 7.4% and 10.7% and the level of porosity decreases from 6.2% to 4.7% with the increment of the sintering temperature. Vickers hardness (280–300 HV30) and tensile properties (different combination of strength and elongation around 900 MPa and 3%) are achieved.

year: 2017-03

title: Sweet as – the [ADJ + as] intensifier construction in Māori English/ Aotearoa English.

authors: Calude, Andreea S.

abstract: We introduce the Waikato Māori English Conversation (MEC) corpus, which consists of 43 dyadic conversations between 49 young adults who self-recorded informal conversations with close friends, in their own homes, with no topic of conversation specified (83 hours of dialogue; nearly 800,000 words). The resulting materials are colloquial and unstructured, capturing a wider range of pragmatic and stylistic modes than is possible in a standard sociolinguistic interview. Here, we report on one such feature, the [ADJ + as] construction, for example: ‘sorry some of the questions are like awkward as’ and ‘that caused a big as drama eh’. This intensifier construction has been identified as a distinctive New Zealand English (NZE) innovation, yet little has been written about this it. However, the Waikato MEC corpus presents the opportunity to analyse the construction in a more systematic manner and to fill existing gaps in analyses of Māori English grammar.

text: Sweet as – the [ADJ + as] intensifier construction in Māori English/ Aotearoa English. We introduce the Waikato Māori English Conversation (MEC) corpus, which consists of 43 dyadic conversations between 49 young adults who self-recorded informal conversations with close friends, in their own homes, with no topic of conversation specified (83 hours of dialogue; nearly 800,000 words). The resulting materials are colloquial and unstructured, capturing a wider range of pragmatic and stylistic modes than is possible in a standard sociolinguistic interview. Here, we report on one such feature, the [ADJ + as] construction, for example: ‘sorry some of the questions are like awkward as’ and ‘that caused a big as drama eh’. This intensifier construction has been identified as a distinctive New Zealand English (NZE) innovation, yet little has been written about this it. However, the Waikato MEC corpus presents the opportunity to analyse the construction in a more systematic manner and to fill existing gaps in analyses of Māori English grammar.

year: 2025