Using Food Wastes in Farm-Based Anaerobic Digesters

DAIRY PRODUCERS ARE INCREASINGLY INTERESTED in mixing food wastes with animal manure as feedstock for anaerobic digesters. Anaerobic digestion (AD) is a biochemical degradation process that converts complex organic materials into biogas in the absence of oxygen. Biogas is composed of methane, carbon dioxide and trace amounts of hydrogen sulfide. Animal wastes, especially dairy manure, have proven to be ideal feedstocks for anaerobic digesters. Food wastes, mostly generated from food processing and food service, also can be excellent feedstocks for AD. Food wastes typically have high ratios of volatile solids-to-total solids (80 – 90%), which indicate high energy content. The volatile solids are the fraction of total solids that can potentially be converted into biogas

The development of an intelligent hybrid active-passive vibration isolator

A hybrid active-passive vibration isolator made up of electromagnetic actuator and air spring in parallel can be used to effectively isolate the broadband and line spectrum vibration of mechanical equipment simultaneously. However, due to its reliability and safety problems caused by the impact, its application in ships is limited. In this paper, an impactresistant structure and an air gap self-sensing method of the passive-active hybrid vibration isolator are proposed and developed on the base of modelling, simulation and analysis. A thin magnetic rubber is filled into the air gap of electromagnetic actuator, which can avoid rigid collision between the armature and the permanent magnet under the action of impact. A suspension armature structure including pre-compression spring is suggested, which can automatically compensate the deformation caused by impact and protect the coil and permanent magnet from impact damage. An air gap self-sensing method is developed through detecting the voltage between the input and output terminals of actuator, which is verified by experiments

Failure behavior of concrete subjected to high dynamic loading of new spiral projectile

A new spiral warhead structure which makes concrete failure by self-rotation is proposed in this paper. Concrete dynamic response when subjected to the oval and new proposed spiral projectile vertical and oblique-angle (from 60° to 70°) impacts of different velocities is studied numerically. This investigation obtains the specific law between different residual velocity and rotation angle when concrete target subjected to the impact loading of spiral projectile ranging from 700 m/s ~ 1000 m/s. It also shows the law between different residual velocity and the groove depth. The rotational angular velocity vs time curves for different working condition are given

Acyclic stereocontrol and chemical diversity & application to the total synthesis of Bafilomycin A₁

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal

Bias-Flip Technique for Frequency Tuning of Piezo-Electric Energy Harvesting Devices

Devices that harvest electrical energy from mechanical vibrations have the problem that the frequency of the source vibration is often not matched to the resonant frequency of the energy harvesting device. Manufacturing tolerances make it difficult to match the Energy Harvesting Device (EHD) resonant frequency to the source vibration frequency, and the source vibration frequency may vary with time. Previous work has recognized that it is possible to tune the resonant frequency of an EHD using a tunable, reactive impedance at the output of the device. The present paper develops the theory of electrical tuning, and proposes the Bias-Flip (BF) technique, to implement this tunable, reactive impedance