Pooya Saketi

Microrobotic platform for manipulation and flexibility measurement of individual paper fibers

This paper introduces a microrobotic platform to manipulate and characterize individual paper fibers. Mechanical characterization of individual paper fibers determines the key parameters which affect the quality of paper sheets. Current laboratory tests are based on bulk paper fiber measurements. This paper presents a microrobotic platform which is able to characterize the flexibility of individual paper fibers directly, not in bulk amount and using indirect estimations. The flexibility of three different pulp samples is measured and the experimental results are reported.

A flexible microrobotic platform for handling microscale specimens of fibrous materials for microscopic studies

One of the most challenging issues faced in handling specimens for microscopy, is avoiding artefacts and structural changes in the samples caused by human errors. In addition, specimen handling is a laborious and time‐consuming task and requires skilful and experienced personnel. This paper introduces a flexible microrobotic platform for the handling of microscale specimens of fibrous materials for various microscopic studies such as scanning electron microscopy and nanotomography. The platform is capable of handling various fibres with diameters ranging from 10 to 1000 μm and lengths of 100 μm–15 mm, and mounting them on different types of specimen holders without damaging them. This tele‐operated microrobotic platform minimizes human interaction with the samples, which is one of the main sources contributory to introducing artefacts into the specimens. The platform also grants a higher throughput and an improved success rate of specimen handling, when compared to the manual processes. The operator does not need extensive experience of microscale manipulation and only a short training period is sufficient to operate the platform. The requirement of easy configurability for various samples and sample holders is typical in the research and development of materials in this field. Therefore, one of the main criteria for the design of the microrobotic platform was the ability to adapt the platform to different specimen handling methods required for microscopic studies. To demonstrate this, three experiments are carried out using the microrobotic platform. In the first experiment, individual paper fibres are mounted successfully on scanning electron microscopy specimen holders for the in situ scanning electron microscopy diagonal compression test of paper fibres. The performance of the microrobotic platform is compared with a skilled laboratory worker performing the same experiment. In the second experiment, a strand of human hair and an individual paper fibre bond are mounted on a specimen holder for nanotomography studies. In the third experiment, individual paper fibre bonds with controlled crossing and vertical angles are made using the microrobotic platform. If an industrial application requires less flexibility but a higher speed when handling one type of sample to a specific holder, then the platform can be automated in the future.

Microrobotic platform for making, manipulating and breaking individual paper fiber bonds

This paper introduces a microrobotic platform to make, manipulate and break individual paper fiber bonds. An individual paper fiber bond is the construction unit of a paper sheet and its properties affect the strength of the entire network of a paper sheet. In one hand, conventional laboratory tests on paper fiber bonds are mainly performed in a hand-sheet level. On the other hand, reported methods for paper fiber bond strength tests in individual bond level are either direct which are manual, laborious and have a low throughput or indirect which require data interpretation. The microrobotic platform presented in this paper performs direct and individual tests on paper fiber bonds. Making, manipulating and breaking individual paper fiber bonds are accomplished successfully demonstrating the first steps towards individual bond strength measurement.

Automated handling of bio-nanowires for nanopackaging

The integration of biomaterials into micro/nano-sensors or micro/nano-systems is expected to improve the properties of such systems or even lead to the development of novel innovative systems. A key problem to be solved beforehand is the development and realization of proper preparation, handling and manipulation methods with respect to an industrial usage. To enable such a usage, the methods have to be automatable, robust to environmental changes as well as feasible in a scanning electron microscope (SEM). According to these points, the target of the presented efforts is to develop these methods for a future design of nanoelectronic parts and to solve packaging problems at the nanoscale. As a consequence, the paper presents a novel concept for the usage of biomaterials, such as DNA and wood fibers/fibrils, for the packaging at the nanoscale. Novel methods for the DNA-handling with an atomic force microscope (AFM) at dry conditions, which can also be used in the vacuum chamber of a SEM will be presented as well as wood fibers/fibrils manipulation methods in the SEM.

Experimental evaluation of Z-directional fibre-fibre bond strength using microrobotics

There is a large interest in the measurement of the Z-directional bond strength in pulp and paper/board industry. Several methods have been developed to measure the Z-directional strength at a handsheet level; however, there is not any reported device capable of the Z-directional fibre-fibre bond strength measurement at a fibre level. This paper presents a novel method for the experimental evaluation of the Z-directional bond strength using microrobotics and a Polyvinylidene fluoride (PVDF) film microforce sensor. In bond strength experiments, different deformation rates are needed. Therefore, the effect of the deformation rate on the performance of the proposed sensor is studied and successful experiments on unrefined bleached softwood kraft pulp fibres are demonstrated.

Electroplated nickel microspring and low-friction precision linear slider: A novel micro-force sensing tool

This paper introduces a novel micro-force sensing approach utilizing an electroplated nickel microspring and a precision linear slider (PLS) for micro-tensile testing applications. After investigating the effects of friction forces in a PLS, an electroplated nickel microspring is designed, fabricated and integrated into the PLS, and the proposed micro-force sensor concept is validated through experimental results. The microspring fabricated in this paper is limited to forces up to 6 mN with the average sensitivity of 36.63 μN/μm. It is shown that the friction forces introduce uncertainties only to the forces less than 500 μN. The proposed approach allows the fabrication of micro-force sensors for the force ranges of up to tens of Millinewtons for different applications.

Automatic image-based detection of paper fiber ends

Understanding the properties of paper fibers and paper fiber bonds can be really significant in improving the quality of paper. The problem in gathering measurement data from individual paper fibers is the lack of reliable and efficient research instruments. Also, without automation the yield of experiments will be low and the results will depend on the skills of the operator. This paper presents an image-based method to automatically detect the endpoints of paper fibers. The method will be utilized in automatic control of a novel and tailor-made paper fiber manipulation and measurement platform. Performance of the method is extremely promising with adequate speed and very accurate results.

Automated modular bacterial filtering system with embeddable microfluidic chips

This paper introduces an automated bacterial filtering system which has three unique advantages comparing to current available systems. Firstly, it is an automatic system which minimizes the human interaction with potentially hazardous bacterial samples, eliminates human errors and makes it suitable for frequent bacterial filtering procedures. Secondly, it provides an interface between milliliter volumes of sample and microfluidic chips requiring samples in microliter volumes. Thirdly, both bacteria collected on the filter and filtrate passed through the filter can be collected for analysis. The modular design of the system provides a large variety of filters for different applications.