An overview of microflown technologies

The Microflown is an acoustic sensor measuring particle velocity instead of sound pressure, which is usually measured by conventional microphones. Since its recent invention it is mostly used for measurement purposes (1D and 3D-sound intensity measurement and acoustic impedance). The Microflown is also used for measuring DC-flows, that can be considered as particle velocity with a frequency of 0Hz. Furthermore the Microflown is used in the professional audio as a low frequency add on microphone for pressure gradient microphones (figure of eight; directional microphones). Due to its small dimensions and silicon based production method the Microflown is very suitable for mobile applications like mobile telephones or smartcards. Nowadays sound-energy determination, array applications and three-dimensional impulse response are under investigation. Although the Microflown was invented only some years ago, the device is already commercially available

The microflown : a true particle velocity microphone; sound intensity application

The Microflown is world's first particle velocity microphone that enables numerous new acoustical applications, due to the combination of its unique acoustical performance and small dimensions. Several patents have been granted since its invention in 1994. This abstract will focus on one application: sound intensity measurements. The direct measurement of particle velocity makes it possible to measure sound intensity in one place. The advantage of this is that the complete audio band can be measured at once now, in the near field, far field and also both in reactive and nonreactive fields. With the use of the Microflown, the realisation of very small three dimensional sound intensity probes will become feasible soon. Some background information of the microflown concerning the manufacturing, signal and noise properties and preamplifiers will be presented

A particle velocity sensor to measure the sound from a structure in the presence of background noise

The performance (or quality) of a product is often checked by measuring the radiated sound (noise) from the vibrating structure. Often this test has to be done in an environment with background noise, which makes the measurement difficult. When using a (pressure) microphone the background noise can be such that it dominates the radiated sound from the vibrating structure. However, when using a particle velocity sensor, the Microflown [1,2], near the vibrating structure, the background noise has almost no influence (it is almost cancelled) and the sound from the structure is measured with a good S/N ratio. The experimental results are explained in terms of the different boundary conditions at the surface of the vibrating structure for the pressure and the particle velocity

The microflown, from die to product

This article reports on various steps to transform a concept to a product. A sound intensity probe based on a micro-machined acoustic sensor "the Microflown" is used as an example. Requirements for the micromachined part are simplicity and uncomplicated processing to reach a high throughput. For monitoring the quality, simple and reliable characterisation tools should be designed as well. To gain credibility independent labs should test the product. The product should offer a complete solution that competes in overall costs and performance, and it must be possible to connect it into existing systems

Within- and between-pen transmission of Classical Swine Fever Virus: a new method to estimate the basic reproduction ratio from transmission experiments

We present a method to estimate basic reproduction ratio R0 from transmission experiments. By using previously published data of experiments with Classical Swine Fever Virus more extensively, we obtained smaller confidence intervals than the martingale method used in the original papers. Moreover, our method allows simultaneous estimation of a reproduction ratio within pens R0w and a modified reproduction ratio between pens R'0b. Resulting estimates of R0w and R'0b for weaner pigs were 100 (95% CI 54.4-186) and 7.77 (4.68-12.9), respectively. For slaughter pigs they were 15.5 (6.20-38.7) and 3.39 (1.54-7.45), respectively. We believe, because of the smaller confidence intervals we were able to obtain, that the method presented here is better suited for use in future experiments

An intuitive handheld acoustic noise source finder

ABSTRACT - An apparatus has been developed to find acoustic sound sources in the near field of a radiating object operating in a noisy environment. It is based on two orthogonally placed particle velocity probes (two Microflowns[1], [2]). The complete signal processing is done in real time with battery powered analogue circuitry, resulting in a very small and handheld measurement device. One Microflown is used to display the sound level and to listen to the source whilst rejecting the background noise and another Microflown is used to create a stereo\ud indication in which direction the device must be moved to pinpoint the noise source

Chronic Stress, Inflammation, and Colon Cancer: A CRH System-Driven Molecular Crosstalk.

Chronic stress is thought to be involved in the occurrence and progression of multiple diseases, via mechanisms that still remain largely unknown. Interestingly, key regulators of the stress response, such as members of the corticotropin-releasing-hormone (CRH) family of neuropeptides and receptors, are now known to be implicated in the regulation of chronic inflammation, one of the predisposing factors for oncogenesis and disease progression. However, an interrelationship between stress, inflammation, and malignancy, at least at the molecular level, still remains unclear. Here, we attempt to summarize the current knowledge that supports the inseparable link between chronic stress, inflammation, and colorectal cancer (CRC), by modulation of a cascade of molecular signaling pathways, which are under the regulation of CRH-family members expressed in the brain and periphery. The understanding of the molecular basis of the link among these processes may provide a step forward towards personalized medicine in terms of CRC diagnosis, prognosis and therapeutic targeting

Source localization using acoustic vector sensors: a music approach

Traditionally, a large array of microphones is used to localize multiple far field sources in acoustics. We present a sound source localization technique that requires far less channels and measurement locations (affecting data channels, setup times and cabling issues). This is achieved by using an acoustic vector sensor (AVS) in air that consists of four collocated sensors: three orthogonally placed acoustic particle velocity sensors and an omnidirectional sound pressure transducer. Experimental evidence is presented demonstrating that a single 4 channel AVS based approach accurately localizes two uncorrelated sources. The method is extended to multiple AVS, increasing the number of sources that can be identified. Theory and measurement results are presented. Attention is paid to the theoretical possibilities and limitations of this approach, as well as the signal processing techniques based on the MUSIC method

ACALYPTRATAE FLIES (DIPTERA: SCHIZOPHORA) FROM VINEGAR TRAPS FROM THE VALBONA VALLEY NATIONAL PARK (ALBANIA)

With an acetic acid trap, ten new Diptera species for the fauna of Albania were caught in the Valbona Valley National Park