Low-cost Setup Research Articles

Improved 3D tracking and automated classification of rodents' behavioral activity using depth-sensing cameras.

Analysis of rodents' behavior/activity is of fundamental importance in many research fields. However, many behavioral experiments still rely on manual scoring, with obvious problems in reproducibility. Despite important advances in video-analysis systems and computational ethology, automated behavior quantification is still a challenge. The need for large training datasets, background stability requirements, and reduction to two-dimensional analysis (impairing full posture characterization), limit their use. Here we present a novel integrated solution for behavioral analysis of individual rats, combining video segmentation, tracking of body parts, and automated classification of behaviors, using machine learning and computer vision methods. Low-cost depth cameras (RGB-D) are used to enable three-dimensional tracking and classification in dark conditions and absence of color contrast. Our solution automatically tracks five anatomical landmarks in dynamic environments and recognizes seven distinct behaviors, within the accuracy range of human annotations. The developed free software was validated in experiments where behavioral differences between Wistar Kyoto and Wistar rats were automatically quantified. The results reveal the capability for effective automated phenotyping. An extended annotated RGB-D dataset is also made publicly available. The proposed solution is an easy-to-use tool, with low-cost setup and powerful 3D segmentation methods (in static/dynamic environments). The ability to work in dark conditions means that natural animal behavior is not affected by recording lights. Furthermore, automated classification is possible with only ~30 minutes of annotated videos. By creating conditions for high-throughput analysis and reproducible quantitative measurements of animal behavior experiments, we believe this contribution can greatly improve behavioral analysis research.

Exfoliated near infrared fluorescent silicate nanosheets for (bio)photonics

Imaging of complex (biological) samples in the near-infrared (NIR) is beneficial due to reduced light scattering, absorption, phototoxicity, and autofluorescence. However, there are few NIR fluorescent materials known and suitable for biomedical applications. Here we exfoliate the layered pigment CaCuSi4O10 (Egyptian Blue, EB) via ball milling and facile tip sonication into NIR fluorescent nanosheets (EB-NS). The size of EB-NS can be tailored to diameters <20 nm and heights down to 1 nm. EB-NS fluoresce at 910 nm and the fluorescence intensity correlates with the number of Cu2+ ions. Furthermore, EB-NS display no bleaching and high brightness compared with other NIR fluorophores. The versatility of EB-NS is demonstrated by in-vivo single-particle tracking and microrheology measurements in Drosophila melanogaster embryos. EB-NS can be uptaken by plants and remotely detected in a low-cost stand-off detection setup. In summary, EB-NS have the potential for a wide range of bioimaging applications.

Holographic astigmatic particle tracking velocimetry (HAPTV)

The formation of twin images in digital inline holography (DIH) prevents the placement of the focal plane in the center of a sample volume for DIH-based particle tracking velocimetry (DIH-PTV) with a single camera. As a result, it is challenging to apply DIH-PTV for flow measurements in large-scale laboratory facilities or many field applications where it would otherwise be desirable due to the low cost and compact setup. Here we introduce holographic astigmatic PTV (HAPTV) by inserting a cylindrical lens in the optical setup of DIH-PTV, generating distorted holograms. Such distortion is subsequently utilized in a customized reconstruction algorithm to distinguish tracers positioned on different sides of the focal plane which can in turn be placed in the middle of a sample volume. Our HAPTV approach is calibrated under high (1 µm pixel−1) and low (10 µm pixel−1) magnifications with an error standard deviation of 4.2 µm (one particle diameter) and 120.7 µm (~5 times the particle diameter), respectively. We compare the velocity field of a laminar jet flow obtained using HAPTV and conventional PIV to illustrate the accuracy of the technique when applied to practical flow measurement applications. The work demonstrates that HAPTV improves upon the depth of field of conventional astigmatic PTV and enables the implementation of DIH-based PTV for in situ applications.

A versatile low-cost experimental set-up and measurement protocol for temperature dependent electrical measurements in the temperature range 100 K – 500 K

A versatile low-cost experimental set-up and adjoining measurement protocol for continuous temperature dependent electrical measurements in the temperature range of 100 K – 500 K is described. The set-up can perform continuous measurements of DC and AC electrical properties of a sample under test (SUT) as a function of its temperature in the mentioned temperature range without any artefacts. The SUT can be in the form of film, or, powders pressed into pellets. The set-up comprises of automatic data acquisition system equipped with LabVIEW programme for real time data acquisition during measurements. The errors involved in the measurements using the set-up have been calculated by measuring the temperature dependent resistance of standard Pt100 RTD temperature sensor and from temperature response of dielectric constant of standard polycrystalline BaTiO3. The high measurement accuracy of the present set-up in artefact-free AC and DC electrical measurements has been demonstrated by measuring the temperature response of the electrical properties of standard polycrystalline BaTiO3, standard polycrystalline SnO2 and nano polycrystalline SnO2 samples.

Estimation of Effect of Fog on Terrestrial Free Space Optical Communication Link

Free Space Optical Communication Technology is expected as the successor to the existing communication technologies as many of its features like high bandwidth, high data rate, low bit error rate, high ease of deployment, license free and hacking free communication (which is almost impossible for the RF systems). Any free space optical link that is to be established at any place needs to be optimized according to the climatic conditions that prevail in that geographical location. Amongst all the climatic conditions like rain, fog, haze, snow, scintillation etc., fog plays predominant role in deteriorating the strength of the signal at a higher rate such that the signal level falls below the Threshold level which leads to outage period. Therefore, the effect of fog on the free space optical link is simulated and analyzed using the parameters like received optical power corresponding electrical power and quality factor. To support the discussion on the effect of fog on FSO link a low-cost experimental setup was designed and the performance of the signal was analyzed. It was observed that both the simulated and experimental results followed a similar pattern.

Novel Grass Hopper optimization based MPPT of PV systems for complex partial shading conditions

Recently depletion of fossil fuels and environmental concerns triggered the extensive research on alternative energy resources, paricularly solar energy. The power of PV systems may be decreased by the oscillation, random fluctuation, and slow speed of their power tracking. To tackle these issues, a novel grasshopper optimization (GHO) technique is implemented to the MPPT controller under fast varying irradiance and PS conditions. A thorough comparison is made with well-established techniques, such as P&O, ABC, PSO, DFO, PSOGS, and CS optimization techniques under 5 different cases of weather conditions. The shortcomings of existing techniques are exposed under complex partial shading (CPS). An adaptive search and skip method is incorporated into GHO to enhance its robustness. Detailed qualitative and statistical analysis is made and results are presented to solidify the feasibility of GHO. The analysis confirms the effectiveness of the proposed GHO over existing bio-inspired MPPT techniques. Results show that the proposed GHO is highly robust with the tracking efficiency of up to 99.5%. The oscillation reduction of up to 85% is achieved along with 14–60% faster tracking. Experimental validation on low-cost setup further solidifies the practicality of the proposed technique in real-world applications.

Measuring the Raman spectrum of water with a smartphone, laser diodes and diffraction grating

We show how low-cost apparatus based on the use of commercial laser diodes, inexpensive diffraction transmission gratings coupled with a smartphone camera, can be assembled and employed to quantitavely measure the wavelengths of photons scattered inelastically as a consequence of the Raman effect. In particular, we measured the Raman shift of water stimulated by violet and green laser radiation.

Accuracy of sand beach topography surveying by drones and photogrammetry

Beaches are characterized by high morphodynamic activity, and high-frequency measurements are needed to understand their states and rates of change. Ideally, beach survey methods should be at once accurate, rapid and low-cost. Recently, unmanned aerial systems (drones) have been increasingly utilized to measure beach topography. In this paper, we present a review of the state of art in drones and photogrammetry for beach surveys and the respective achieved measurement quality (where reported). We then show how drones with a minimal configuration and a low-cost setup can meet the high accuracy and rapidity required for beach surveys. To test a minimal drone and ground control point configuration, we used consumer-grade equipment to perform the same flight path with different cameras and at different altitudes. We then used photogrammetry to produce digital elevation models of the beach. Using a GNSS-RTK system, we collected 2950 independent control points to evaluate the accuracy of the digital elevation models. Results show that, once a few potential sources of uncertainties in the final digital elevation model are taken into account, the average RMSE(z) of the digital elevation models was ~5 cm, with a survey efficiency of ca. 3 m2 min−1. Digital elevation models taken at different times were used to calculate the before–after sediment budget following a storm that hit a sandy coast in Sylt Island at the German North Sea coast.

Mechanical characterization and comparison of additive manufactured ABS, Polyflex™ and ABS/Polyflex™ blended functional prototypes

Purpose Additive manufacturing (AM) is one of the latest and most advanced technologies that are continuously expanding into various field applications. Undoubtedly, fused deposition modeling (FDM) is one of the oldest and extensively used AM technologies not only because of the advantage of low cost, comparatively moderate production speed and negligible wastage but also due to acceptance of a wide range of thermoplastics, reinforced and blended feedstock for making the end product suitable for service. The purpose of this work to perform mechanical characterization of standard samples printed on FDM with acrylonitrile butadiene styrene (ABS), shape memory polymer (SMP; make PolyflexTM) and ABS/PolyflexTM blend and a comparative study from AM view point. Design/methodology/approach A low-cost desktop-based FDM setup was used for the fabrication of the test specimens under different processing conditions. Experiments were conducted as per obtained control log, and statistical analysis was conducted to understand the effect of selected variables in response of measured properties. Further, scanning electron microscopy-based micrographs were analyzed to understand the fracture mechanisms. Findings The obtained results highlighted that the mechanical properties of FDM parts are strongly influenced by the selected process variables. However, in case of most of the measured properties, selection of suitable feedstock has dominated the other input variables. Further, the results of test parts made with in-house developed ABS/SMP blend have showed the attainment of remarkable values of both strength and elasticity. Originality/value This work is held to empower the use of FDM technology to fabricate advanced and robust components for serving highly demanding applications.

Hardness and toughness evaluation of developed Al metal matrix composite using stir casting method

Composite materials have many unique properties which mostly conventional materials usually do not comprise. One of these properties is the better volume to weight ratio which is very useful for designing of components of aircrafts, automobiles, domestic appliances and electronic devices. However some challenges occur in development of homogenous metal matrix composites because of different phases of matrix material and reinforcement materials. In this study, three different aluminium based metal matrix composites have been developed by varying the percentage of matrix (Al6063) and reinforcement (flyash and Al2O3) materials by using stir casting method and after that the hardness and toughness have been determined. Stir casting method has been used because of its low cost setup and portability. Result shows that the contribution of Al2O3 particles plays an important role in increasing the hardness of composite material.

Deep learning virtual colorful lens-free on-chip microscopy

Currently, it is generally known that lens-free holographic microscopy, which has no imaging lens, can realize a large field-of-view imaging with a low-cost setup. However, in order to obtain colorful images, traditional lens-free holographic microscopy should utilize at least three quasi-chromatic light sources of discrete wavelengths, such as red LED, green LED, and blue LED. Here, we present a virtual colorization by deep learning methods to transfer a gray lens-free microscopy image into a colorful image. Through pairs of images, i.e., grayscale lens-free microscopy images under green LED at 550 nm illumination and colorful bright-field microscopy images, a generative adversarial network (GAN) is trained, and its effectiveness of virtual colorization is proved by applying it to hematoxylin and eosin stained pathological tissue samples imaging. Our computational virtual colorization method might strengthen the monochromatic illumination lens-free microscopy in medical pathology applications and label staining biomedical research.

Using smartphone flashlight as slit lamp light source.

In the event of a power outage, the smartphone flashlight may be used as a light source for the slit lamp. First, the outer casing of the slit lamp tower is removed [Fig. 1], followed by the removal of the bulb and the condensing lens [Fig. 2]. The phone flashlight is turned on, centered over the slit apparatus and taped in place [Figs. 3 and 4]. This produces a bright slit beam of adjustable height/width comparable to that of the original bulb. The cobalt blue filter can be applied as needed. This low-cost setup may be useful in an emergency when the power outage occurs unexpectedly when there is a bulb malfunction without an adequate replacement, or in areas of low resources during electricity rationing.[1]Figure 1: The outer casing of the slit lamp tower is removedFigure 2: The bulb and condensing lens are removedFigure 3: Smart phone flashlight is turned on, centered over the slit apparatus and taped in placeFigure 4: A bright, adjustable slit beam is producedFinancial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Sensors, Biosensors, and Analytical Technologies for Aquaculture Water Quality.

In aquaculture industry, fish, shellfish, and aquatic plants are cultivated in fresh, salt, or brackish waters. The increasing demand of aquatic products has stimulated the rapid growth of aquaculture industries. How to effectively monitor and control water quality is one of the key concerns for aquaculture industry to ensure high productivity and high quality. There are four major categories of water quality concerns that affect aquaculture cultivations, namely, (1) physical parameters, e.g., pH, temperature, dissolved oxygen, and salinity, (2) organic contaminants, (3) biochemical hazards, e.g., cyanotoxins, and (4) biological contaminants, i.e., pathogens. While the physical parameters are affected by climate changes, the latter three are considered as environmental factors. In this review, we provide a comprehensive summary of sensors, biosensors, and analytical technologies available for monitoring aquaculture water quality. They include low-cost commercial sensors and sensor network setups for physical parameters. They also include chromatography, mass spectrometry, biochemistry, and molecular methods (e.g., immunoassays and polymerase chain reaction assays), culture-based method, and biophysical technologies (e.g., biosensors and nanosensors) for environmental contamination factors. According to the different levels of sophistication of various analytical techniques and the information they can provide (either fine fingerprint, highly accurate quantification, semiquantification, qualitative detection, or fast screening), we will comment on how they may be used as complementary tools, as well as their potential and gaps toward current demand of real-time, online, and/or onsite detection.

Low-cost conditioned place preference setup including video recording and analysis of behaviour

The conditioned place preference (CPP) paradigm is widely used in rodent research to test the rewarding and aversive properties of different stimuli. Despite its relative simplicity, commercially available CPP systems are often costly. Here we describe the construction of a CPP setup and a behavioral data analysis pipeline incorporating:• a CPP box which can be built in a single day by using widely available and affordable materials.• an open source computer system for data acquisition (based on Raspberry Pi).• a freely available behavioural analysis software.The behavioural analysis allows for measurement of both locomotor activity and time spent in a zone of interest. Including all components, our setup costs ~1/10 of the cost of the least expensive commercially available CPP boxes alone (not including data acquisition and analysis). We validated the setup by showing that a 4 mg/kg dose of amphetamine increases locomotor activity acutely in adolescent male mice and induces conditioned preference for the drug-paired compartment in the CPP test.

Mechanical characterization of millimetric agarose spheres using a resonant technique

This paper presents a methodology for the mechanical characterization of agarose millimetric spheres using resonant principles. Detection of the modes of vibration was conducted using a low-cost experimental setup based on an electret microphone adapted with a thin latex elastic membrane for the sensing stage and a piezoelectric actuator driven by a conventional transformer for the excitation stage. The identification of vibration modes is supported through an ANSYS Finite Element model of the experimental setup. Experimental and numerical results demonstrate that two modes of vibration, known as Quadrupole and Octupole, appear in the amplitude spectrum and can be used to obtain stiffness values for the samples. Following this approach, Young’s modulus of 209 ± 19.80, 338 ± 35.30 and 646 ± 109 kPa for 2%, 3% and 4% agarose millimetric spheres were calculated.

Robust Plane Wave Generator Design in Small Anechoic Chamber Setup Using Parameterized Field Method

Plane Wave Generator (PWG) has attracted great research interest in the industry and academia for sub-6 GHz massive MIMO base station (BS) measurement, thanks to its low-cost and smaller system setup. One major concern in the small setup is its high reflectivity level inside the anechoic chamber, which might distort the quiet zone performance significantly. Meanwhile, it is critical that the quiet zone performance is insusceptible to system inaccuracies. However, these two aspects are largely overlooked in the plane wave synthesis (PWS) study in the literature. In this article, a new PWS strategy is proposed based on parametrized field distribution over an enlarged sampling area. The proposed method offers robust design and low reflectivity level. The effectiveness and robustness of the proposed PWS strategy is demonstrated in a numerical simulation.

Characterization of Si-DLC films synthesized by low cost plasma-enhanced chemical vapor deposition

Diamond-like carbon (DLC) coatings offer versatile applications in surface engineering due to high hardness and strength, chemical and radiation resistance, biocompatibility and low friction coefficient. When doped with Si, such coatings demonstrate even more beneficial properties, such as lower friction coefficient and higher thermal stability. We demonstrate the instrumental developments of a plasma-enhanced chemical vapor deposition (PECVD) method and the use of an original low-cost set-up aimed to synthesize Si-doped DLC films using polyphenylmethylsiloxane (PFMS) precursors. These films on the surface of glass substrate were characterized by means of XPS, AFM, Raman spectroscopy, and nanoindentation. Dry fiction coefficient was found to be reduced for Si-doped DLC for 4–6 times in comparison with glass substrate.

Biophysical Characterization of (Silica-coated) Cobalt Ferrite Nanoparticles for Hyperthermia Treatment.

Magnetic hyperthermia is a technique that describes the heating of material through an external magnetic field. Classic hyperthermia is a medical condition where the human body overheats, being usually triggered by a heat stroke, which can lead to severe damage to organs and tissue due to the denaturation of cells. In modern medicine, hyperthermia can be deliberately induced to specified parts of the body to destroy malignant cells. Magnetic hyperthermia describes the way that this overheating is induced and it has the inherent advantage of being a minimal invasive method when compared to traditional surgery methods. This work presents a particle system that offers huge potential for hyperthermia treatments, given its good loss value, i.e., the particles dissipate a lot of heat to their surroundings when treated with an ac magnetic field. The measurements were performed in a low-cost custom hyperthermia setup. Additional toxicity assessments on Jurkat cells show a very low short-term toxicity on the particles and a moderate low toxicity after two days due to the prevalent health concerns towards nanoparticles in organisms.

Experimental Investigation of the Settling Characteristics of Carbon and Metal Oxide Nanofuels

Fuels dispersed with engineered nanoparticle additives, or nanofuels, are desirable for the vastly different combustion properties such as combustion rate and ignition delay they exhibit compared to base fuels. The stability of such nanofuels over time and under different particle loadings is a very important parameter to consider before they can be put into practical use. Many techniques exist today to analyze suspension stability, which have been developed to analyze water-based nanofluids. Sometimes these techniques can be expensive, and/or require specialized equipment, and/or require a method that is invasive and disturbs the suspension. Present research uses a non-contact, non-invasive, low-cost experimental setup to analyze suspension stability over long periods of time. Nanofuels made from carbon-based nanomaterials (acetylene black, multiwalled carbon nanotubes) and metal oxide nanomaterials (copper oxide, aluminum oxide) with hydrocarbon fuels (canola biodiesel, petrodiesel) have been prepared and their settling rates have been analyzed over the period of three days. It is found that metal oxides go through several metastable states as they settle. The effect of initial concentration and liquid column height is shown. It is hoped that present research showcases the positive traits of the presented technique and will spark further interest in nanofuel stability.

Fluctuating light experiments and semi-automated plant phenotyping enabled by self-built growth racks and simple upgrades to the IMAGING-PAM

BackgroundOver the last years, several plant science labs have started to employ fluctuating growth light conditions to simulate natural light regimes more closely. Many plant mutants reveal quantifiable effects under fluctuating light despite being indistinguishable from wild-type plants under standard constant light. Moreover, many subtle plant phenotypes become intensified and thus can be studied in more detail. This observation has caused a paradigm shift within the photosynthesis research community and an increasing number of scientists are interested in using fluctuating light growth conditions. However, high installation costs for commercial controllable LED setups as well as costly phenotyping equipment can make it hard for small academic groups to compete in this emerging field.ResultsWe show a simple do-it-yourself approach to enable fluctuating light growth experiments. Our results using previously published fluctuating light sensitive mutants, stn7 and pgr5, confirm that our low-cost setup yields similar results as top-prized commercial growth regimes. Moreover, we show how we increased the throughput of our Walz IMAGING-PAM, also found in many other departments around the world. We have designed a Python and R-based open source toolkit that allows for semi-automated sample segmentation and data analysis thereby reducing the processing bottleneck of large experimental datasets. We provide detailed instructions on how to build and functionally test each setup.ConclusionsWith material costs well below USD$1000, it is possible to setup a fluctuating light rack including a constant light control shelf for comparison. This allows more scientists to perform experiments closer to natural light conditions and contribute to an emerging research field. A small addition to the IMAGING-PAM hardware not only increases sample throughput but also enables larger-scale plant phenotyping with automated data analysis.