Saddle Force Mapping

In horseback riding, the size and shape of a saddle can drastically effect the comfort, attitude and performance of the horse as well as the effectiveness of the rider. In an effort to create an accurate means of fitting the saddle to the horse, I have created a pressure sensing device that maps the force differences along critical areas of the horse\u27s back during motion. Using an Arduino microprocessor and appropriate circuits, data was collected about the pressure levels between the saddle and the horse\u27s back and a graphic representation of the findings was created

Atomic force microscopic investigation of commercial pressure sensitive adhesives for forensic analysis

Pressure sensitive adhesive (PSA), such as those used in packaging and adhesive tapes, are very often encountered in forensic investigations. In criminal activities, packaging tapes may be used for sealing packets containing drugs, explosive devices, or questioned documents, while adhesive and electrical tapes are used occasionally in kidnapping cases. In this work, the potential of using atomic force microscopy (AFM) in both imaging and force mapping (FM) modes to derive additional analytical information from PSAs is demonstrated. AFM has been used to illustrate differences in the ultrastructural and nanomechanical properties of three visually distinguishable commercial PSAs to first test the feasibility of using this technique. Subsequently, AFM was used to detect nanoscopic differences between three visually indistinguishable PSAs

Structured Water Molecules on Membrane Proteins Resolved by Atomic Force Microscopy

Water structuring on the outer surface of protein molecules called the hydration shell is essential as well as the internal water structures for higher-order structuring of protein molecules and their biological activities in vivo. We now show the molecular-scale hydration structure measurements of native purple membrane patches composed of proton pump proteins by a noninvasive three-dimensional force mapping technique based on frequency modulation atomic force microscopy. We successfully resolved the ordered water molecules localized near the proton uptake channels on the cytoplasmic side of the individual bacteriorhodopsin proteins in the purple membrane. We demonstrate that the three-dimensional force mapping can be widely applicable for molecular-scale investigations of the solid–liquid interfaces of various soft nanomaterials

Identification Techniques Applied to a Passive Elasto-magnetic Suspension

The paper presents an experimental passive elasto-magnetic suspension based on rare-earth permanent magnets, characterized by negligible dependence on mass of its natural frequency. The nonlinear behaviour of this system, equipped with a traditional linear elastic spring coupled to a magnetic spring, is analysed in time domain, for non-zero initial conditions, and in frequency domain, by applying sweep excitations to the test rig base. The dynamics of the system is very complex in dependence of the magnetic contribution, showing both hardening behaviour in the elasto-magnetic setup, and softening motion amplitude dependent behaviour in the purely magnetic case. Hence it is necessary to adopt nonlinear identification techniques, such as non-parametric restoring force mapping method and direct parametric estimation technique, in order to identify the system parameters in the different configurations. Finally, it is discussed the ability of identified versus analytical models in reproducing the nonlinear dependency of frequency on motion amplitude and the presence of jump phenomen

Nano-imaging and its applications to biomedicine

Nanotechnology tools, such as Atomic Force Microscopy (AFM), are now becoming widely used in life sciences and biomedicine. AFM is a versatile technique that allows studying at the nanoscale the morphological, dynamic, and mechanical properties of biological samples, such as living cells, biomolecules, and tissues under physiological conditions. In this article, an overview of the principles of AFM will be first presented and this will be followed by discussion of some of our own recent work on the applications of AFM imaging to biomedicine

A Cost-Effective and Smart Sensing Tissue-like Testbed for Surgical Training

A low-cost tissue-like testbed with six nodes of varying stiffness was developed for surgical training to provide pressure and force feedback data through image reception to human operators. Using SolidWorks, a 3D model of the box trainer housing was created. A pad for the distribution of smartsensing nodes and microcontroller connections was designed with open spaces for the respective components. The pad was 3D-printed with PLA filament. Flat piezoelectric pressure sensors were fabricated with conductive materials and velostat sensor material. Using static and dynamic analyses, three top sensors were chosen to be used in three pressure sensing nodes. A calibration process was performed on the pressure sensors to find the linear relationship between voltage and pressure, which was then used to create a conversion equation for each sensor. These equations were used to collect data at the three pressure sensing nodes on the silicone testbed pad. Conductive TPU filament was used to 3D-print vertical force sensors, which were designed using SolidWorks. The force sensors were calibrated with a squeezing mechanism to find a relationship between voltage and force and to subsequently develop a conversion equation for each sensor. We used these equations to collect force data from the three force sensing nodes on the testbed pad. Through static and dynamic analyses, the force sensors were found to be functional, but to need improvements in accuracy. The mechatronic system was designed and developed to integrate all six sensors and to collect data from the testbed pad using an Arduino microcontroller. The flat pressure and vertical force sensors were embedded in each node to measure the pressure and force that occurs during the deformation of the six nodes. Data was collected and imported into MATLAB. This data was used in displaying pressure and force mapping of the nodes over a live video of the silicone pad. Pressure and force mapping was realized by drawing color-coded circles on each of the six nodes that correspond to a range of force or pressure values. From this development, the surgical testbed provides multi-stiffness tissue training with live pressure and force mapping overlaid on a live video of the emulated surgical field