Unveiling the matrix effect on Bacillus licheniformis and Bacillus subtilis spores heat inactivation between plant-based milk alternatives, bovine milk and culture medium.

This study examined the inactivation of spores of Bacillus licheniformis and Bacillus subtilis in four pea-based milk alternatives, semi-skimmed bovine milk and Brain Heart Infusion (BHI) broth to assess the matrix impact on the thermal inactivation of bacterial spores. Heat inactivation was performed with the method of capillary tubes in temperature range 97-110 °C. A four-parameter non-linear model, including initial level, shoulder duration, inactivation rate and tailing, was fitted to the data obtained.

A profile of two different applicant test batteries with regards to sex and age in successful law enforcement applicants.

Background: Law enforcement (LE) applicant assessments and initial academy training vary greatly across the United States of America (USA), with 820+ academies operating across 50 different states. Rising obesity and declining physical fitness underscore the need for benchmarks of applicant physical performance.

Objective: Create a "point-in-time" descriptive profile of the performance of LE applicants and determine any differences between males, females, and age using two applicant test batteries (ATBs).

On the area-averaged effective sound absorption coefficient of porous materials excited by a monopole.

The area-averaged effective sound absorption coefficient (SAC) of a rigid-backed homogeneous porous material subjected to a monopole excitation is calculated as the absorbed-to-incident sound power ratio. Using Allard's model to describe the sound propagation above the porous material, an analytical model for this power-based SAC is proposed and proves to give a good approximation of the sound absorption performance under monopole excitation of sufficiently large areas of material. The impact of factors on the power-based SAC, such as monopole height, material radial dimension used to calculate the sound powers, and material properties is discussed.

Series and parallel coupling of 3D printed micro-perforated panels and coiled quarter wavelength tubes.

Micro-perforated panel sound absorbers are widely used in noise control applications in the fields of architectural acoustics and transport acoustics. Combining micro-perforated panels with other resonant or sound absorbing systems may broaden the frequency range in which they absorb sound while ensuring that large sound absorption values are reached. In this work, a hybrid sound absorber that combines a micro-perforated panel and a coiled quarter wavelength tube is proposed.

Comparison of three full-field optical measurement techniques applied to vibration analysis.

Digital image correlation, deflectometry and digital holography are some of the full-field optical measurement techniques that have matured in recent years. Their use in vibroacoustic applications is gaining attention and there is a need for cataloging their performance in order to provide, to a broad community of users and potential future users, quantitative and qualitative evaluations of these three approaches. This paper presents an experimental comparison of the three optical methods in the context of vibration measurements, along with classical reference measurements provided by an accelerometer and a laser Doppler vibrometer.