In this article, we propose a novel microfluidic microstrip electromagnetic band gap (EBG) sensor realized using cost-effective 3D printing technology. Microstrip sensor allows monitoring of the ...fluid properties flowing in the microchannel embedded between the microstrip line and ground plane. The sensor's operating principle is based on the phase-shift method, which allows the characterization at a single operating frequency of 6 GHz. The defected electromagnetic band gap (EBG) structure is realized as a pattern in the microstrip ground plane to improve sensor sensitivity. The designed microfluidic channel is fabricated using a fused deposition modelling (FDM) 3D printing process without additional supporting layers, while the conductive layers are realized using sticky aluminium tape. The measurement results show that the change of permittivity of the fluid in the microfluidic channel from 1 to 80 results in the phase-shift difference of almost 90°. The potential application is demonstrated through the implementation of a proposed sensor for the detection of toluene concentration in toluene-methanol mixture where various concentrations of toluene were analysed.
This paper presents an autonomous robotic system, an unmanned ground vehicle (UGV), for in-field soil sampling and analysis of nitrates. Compared to standard methods of soil analysis it has several ...advantages: each sample is individually analyzed compared to average sample analysis in standard methods; each sample is georeferenced, providing a map for precision base fertilizing; the process is fully autonomous; samples are analyzed in real-time, approximately 30 min per sample; and lightweight for less soil compaction. The robotic system has several modules: commercial robotic platform, anchoring module, sampling module, sample preparation module, sample analysis module, and communication module. The system is augmented with an in-house developed cloud-based platform. This platform uses satellite images, and an artificial intelligence (AI) proprietary algorithm to divide the target field into representative zones for sampling, thus, reducing and optimizing the number and locations of the samples. Based on this, a task is created for the robot to automatically sample at those locations. The user is provided with an in-house developed smartphone app enabling overview and monitoring of the task, changing the positions, removing and adding of the sampling points. The results of the measurements are uploaded to the cloud for further analysis and the creation of prescription maps for variable rate base fertilization.
Due to the global water crisis, there is a strong need for real-time water quality monitoring with high temporal and spatial resolutions. This article presents an economical multiparameter water ...quality monitoring system for continuous monitoring of fresh waters. It is based on a sensor node that integrates turbidity, temperature, and conductivity sensors, a miniature 18-channel spectrophotometer, and a sensor for the detection of thermotolerant coliforms, which is a major novelty of the system. Due to the influence of water impurities on the measurement of thermotolerant coliforms, a heuristic method has been developed to mitigate this effect. Moreover, the sensor is low power, and with an integrated long-range wide-area network module, it comprises a system that is wireless sensor network ready and can send data to a dedicated server. In addition, the system is submersible, capable of long-term field operation, and significantly cheaper in comparison to existing solutions. The purpose of the system is to give early warning of incidental pollution situations, thus enabling authorities to take action regarding further prevention of such occasions.
The connection of macrosystems with microsystems for in-line measurements is important in different biotechnological processes as it enables precise and accurate monitoring of process parameters at a ...small scale, which can provide valuable insights into the process, and ultimately lead to improved process control and optimization. Additionally, it allows continuous monitoring without the need for manual sampling and analysis, leading to more efficient and cost-effective production. In this paper, a 3D printed microfluidic (MF) chip for glucose (Glc) sensing in a liquid analyte is proposed. The chip made in Poly(methyl methacrylate) (PMMA) contains integrated serpentine-based micromixers realized via stereolithography with a slot for USB-like integration of commercial DropSens electrodes. After adjusting the sample's pH in the first micromixer, small volumes of the sample and enzyme are mixed in the second micromixer and lead to a sensing chamber where the Glc concentration is measured via chronoamperometry. The sensing potential was examined for Glc concentrations in acetate buffer in the range of 0.1-100 mg/mL and afterward tested for Glc sensing in a cell culturing medium. The proposed chip showed great potential for connection with macrosystems, such as bioreactors, for direct in-line monitoring of a quality parameter in a liquid sample.
Microfluidic chips have become attractive devices with enormous potential for a wide range of applications. The optimal performances of microfluidic platforms cannot be achieved using a single ...fabrication technique. The method of obtaining the dominant characteristic of a microfluidic chip is to combine the best qualities of different technological processes and materials. In this paper, we propose a novel, cost-effective, hybrid microfluidic chip manufacturing technologies that combine 3D printing process and xurographic technique. The standard Y-mixer was 3D printed using thermoplastic polymers, while the enclosure of the channel was achieved using the PVC lamination foils. The influence of the fabrication parameters, materials and bonding layers on the channel dimensions, performances and durability in the process of chip realization have been analysed and tested. Optimized parameters have been established for 3D fabrication process. The potential application in biomedicine and material science has been demonstrated on the example with nickel-titanium (NiTi) orthodontic archwire.
•Waveguide structure supporting acoustic spoof plasmon polaritons perturbed by a defect.•Controllable transmission with uniform phase distribution and steep narrowband response.•Potential ...applications include advanced filters, isolators, and sensor technology.
We study a waveguide structure supporting acoustic spoof plasmon polaritons (aSSPPs) perturbed by a defect, whose specifically tailored geometry enables controllable transmission characterized by a uniform phase distribution and very steep narrowband response. The structure is analyzed using transmission-line theory and numerical simulations, providing evidence for its use in advanced filters, isolators and sensor technology. In order to demonstrate the applicability of the aSSPP waveguide with defect, two selective narrowband filter designs are discussed and explored. Furthermore, we propose an acoustic isolator that exploits steady fluid flow to break reciprocity and provide large isolation in a narrowband region. We also propose a sensor for liquid analytes, in which the grooves of the aSSPP waveguide serve as microfluidic channels, while the sensing principle is based on the spectral shift of the transmission peak for different mixtures of water and glycerol. The sensor shows a good sensitivity and fast response, with a potential for further development for applications in water quality monitoring.
In the last decade, biocidal materials have been extensively researched and applied as a coating for various touchscreen devices, in medicine and civil engineering. This research addresses important ...practical issues in application of surface- modified biocidal glass in water, and inspects optical properties in the spectral range between 350 nm and 500 nm, the range important for bacteria fluorescence detection. Testing of biocidal efficiency has been conducted in an environment rich with microorganisms and algae. To incorporate silver ions in soda lime glass plates, an ion-exchange process in a molten bath was used. The optical characterization of as-synthesized samples indicates very high transparency, above 90% at 440 nm, specifically important for escherichia coli detection. fter 140 days in the bioreactor, it was found that glass heated for 15 min at 350
C produced best results, maintaining transparency above 85% in spectral range from 350 nm to 1000 nm.
In the last decade, biocidal materials have been extensively researched and applied as a coating for various touchscreen devices, in medicine and civil engineering. This research addresses important ...practical issues in application of surface- modified biocidal glass in water, and inspects optical properties in the spectral range between 350 nm and 500 nm, the range important for bacteria fluorescence detection. Testing of biocidal efficiency has been conducted in an environment rich with microorganisms and algae. To incorporate silver ions in soda lime glass plates, an ion-exchange process in a molten bath was used. The optical characterization of as-synthesized samples indicates very high transparency, above 90% at 440 nm, specifically important for escherichia coli detection. fter 140 days in the bioreactor, it was found that glass heated for 15 min at 350
C produced best results, maintaining transparency above 85% in spectral range from 350 nm to 1000 nm.
•Plant-O-Meter is suitable for low-cost, easy-to-perform, plant status measurements.•The device is supported by android app for generation of real-time maps of vegetation indices.•NDVI measured by ...the device was strongly correlated to the NDVI obtained by hyperspectral camera.•The performance of the device is not affected by the different illumination conditions.
Plant stress monitoring is of crucial importance to understand the plant response to environmental conditions, and has been widely applied in various fields including biology, agronomy, botany, and horticulture. A number of methods and instruments for plant stress monitoring have been proposed, most of which show significant disadvantages such as high cost, poor accuracy or complex operation that limit the use of such devices. In this paper, we propose a low cost, portable active multispectral optical device for precise plant stress detection and field mapping named Plant-O-Meter. The device has an integrated multispectral source that comprises light sources of the four most indicative wavelengths (850, 630, 535 and 465 nm), and enables simultaneous illumination of the whole plant. Sequential illumination and detection provide rapid reflectance measurements, which are wirelessly transmitted to android operated devices for processing and data storing. The device was tested in laboratory conditions comparing the Plant-O-Meter measurements with the image results from a SPECIM hyperspectral camera and a GreenSeeker handheld device and under field conditions with the GreenSeeker. The comparison revealed comparable performance, showing strong correlation with both the hyperspectral (R2 = 0.997) and the GreenSeeker handheld (R2 = 0.954 from the laboratory measurements and R2 = 0.886 from the field experiments), indicating that the device exhibits strong potential for accurate plant stress measurements. Moreover, owing to the very simple operating principle, the device represents a compact, cost-effective, and easy-to-operate solution.
In this paper, we propose a novel microstrip-ridge gap waveguide (MS-RGW) filter configuration, which is based on cavity resonators with mushroom inclusions. The resonators are realized as defects in ...surrounding mushroom-based perfect magnetic conductor (PMC), and thus, the filter configuration does not require additional conductive layers nor rearrangement of the PMC elements. The hosting MS-RGW is fed through transition from SMA to microstrip ridge, enabling simple fabrication and excellent impedance matching in a wide frequency range. To demonstrate the potential of the proposed structure, four narrowband filters have been designed, fabricated, and measured. The filters exhibit excellent in-band characteristics and small dimensions.
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