The aim of this work is to show the possibility to realize accelerometers through 3D-printing technique and to investigate the potentiality of these devices. The feasibility of such accelerometers is studied considering the capability of printers to extrude both insulating and conductive materials. Different types of geometries with different characteristics and performance are carefully analyzed and their advantages and disadvantages are determined. The research focuses mainly on differential capacitive accelerometers, today extremely widespread and that can be realized relatively easily via 3D printing, provided that both insulating and conductive materials can be used with the same printer. The printed sensor has been stimulated on each axis with mechanical oscillations produced by a loudspeaker connected to a signal generator. The output signal from the sensor has been read employing an electronic interface for differential capacitive sensors. The obtained experimental results are in a good accordance with those theoretically predicted.
This work focuses on the temperature monitoring inside a polydimethylsiloxane microfluidic chip, suitable for DNA amplification. In order to achieve this aim, the microfluidic chip has been thermally coupled with a lab-on-chip integrating, on a single glass substrate, temperature sensors and thin film heater. The wells of the chip have been filled with thermochromic liquid crystals, that change their optical properties at a precise transition temperature (TT). Experiments have been performed cycling the chip temperatures between 90 ℃ and 50 ℃, two temperatures very close to the annealing and denaturation steps of the standard Polymerase Chain Reaction (PCR), utilized for DNA amplification. Results state that the temperature distribution inside the wells follows values and spatial uniformity required by the PCR cycles, guaranteeing an effective heat transfer from the thin film resistor to the microfluidic chip. Gel electrophoresis of amplified samples showed the presence of the amplifications and thus the successful implementation of the PCR in our lab-on-chip.
The selective detection of volatile organic compounds (VOCs) represents a recently investigated approach that could provide information about the alteration of biological processes. As reported in literature, human biological samples (e.g., saliva, urine, breath, etc.) express different VOCs that could provide information on human health status (e.g., drugs therapies, metabolic/biochemical processes, lung cancer, oral squamous cell carcinoma, hepatocarcinoma etc.). In this work we focused on the detection of butanoic, propanoic, and butanedioic acids since they are contained in different biochemical processes. The aim of this work is the fabrication of thin nanoporous films of synthetic zeolite for the selective adsorption/desorption of butyric, propionic, and succinic acids. The detection is performed by the assessment of emission profiles through a photoionization technique. Results evidenced that zeolite layer is highly selective to propionic acid, allowing a higher adsorption. Conversely, butyric acid emissive profile evidenced adsorption levels 5 times less respect to the propionic acid.
A feasibility study on micromanipulation performed by a novel, multi-hinge microgripper with high mechanical dexterity and complex in-plane motion is herein presented. Thanks to design concepts based on selective flexibility, the device is highly compact and easy to be manufactured by means of MEMS technologies. In the presented experimental test case, the microgripper was immersed in a complex mixture, made of saline solution with floating agarose-based microbeads as target objects; direct contact tests were carried out via microscope observation of the jaw-tips operational window. The results highlight the function capability of clamping objects of tens of microns in size, encouraging further developments toward the manipulation of actual cells.
Construction sites are risky places for work-related injuries. Constant monitoring of workers and people within the site is particularly important, and this can be achieved by using smart devices. This work proposes a system based on UHF RFID technology, which uses tags to monitor workers and gear access to the site. It also communicates detected data on a remote server using MQTT protocol, that ensure high scalability of the system, allowing the use of several nodes to also in different areas and so making it possible to evaluate workers position.
