In this paper, a compact glucose concentration sensor is designed based on an electric-LC (ELC) resonator coupled with a coplanar waveguide (CPW) transmission line, and the ELC resonator is no longer aligned with the CPW transmission line axis. The principle of the sensor is based on the notch depth in the transmission coefficient (S ₂₁ ) depending on the glucose concentration, and it is applied using a micropipette into a cylindrical plastic sample chamber that covers the gap in the middle branch of the ELC resonator. The notch magnitude in the transmission coefficient response behavior was measured and analyzed in the range of 2.5-6 GHz with air, deionized water, phosphate buffered saline (PBS), and different glucose concentrations in deionized water and PBS in the range of 0%-20% (w/V). The experimental results showed that the proposed sensor has good detection of the glucose concentration with high linearity and wide dynamic range. A prototype of the sensor provides an opportunity for the development of a biological and chemical sensing application in the future.

The water displacement and flotation are two of the most accurate and rapid methods for grading and assessing freshness of agricultural products based on density determination. However, these techniques are still not suitable for use in agricultural inspections of products such as eggs that absorb water which can be considered intrusive or destructive and can affect the result of measurements. Here we present a novel proposal for a method of non-destructive, non-invasive, low cost, simple and real—time monitoring of the grading and freshness assessment of eggs based on density detection using machine vision and a weighing sensor. This is the first proposal that divides egg freshness into intervals through density measurements. The machine vision system was developed for the measurement of external physical characteristics (length and breadth) of eggs for evaluating their volume. The weighing system was developed for the measurement of the weight of the egg. Egg weight and volume were used to calculate density for grading and egg freshness assessment. The proposed system could measure the weight, volume and density with an accuracy of 99.88%, 98.26% and 99.02%, respectively. The results showed that the weight and freshness of eggs stored at room temperature decreased with storage time. The relationship between density and percentage of freshness was linear for the all sizes of eggs, the coefficient of determination (R²) of 0.9982, 0.9999, 0.9996, 0.9996 and 0.9994 for classified egg size classified 0, 1, 2, 3 and 4, respectively. This study shows that egg freshness can be determined through density without using water to test for water displacement or egg flotation which has future potential as a measuring system important for the poultry industry.

This is the first report of the construction of a metamaterial-inspired microwave sensor for concentration measurements of aqueous phosphate, nitrate, and mixed phosphate and nitrated solutions. The design of the proposed device is based on a microstrip line (ML) coupled square complementary split-ring resonator (SCSRR), which is squeezed to the narrow width of the slot in the active area. Phosphate, nitrate, and mixed phosphate and nitrate with different liquid sample concentrations inside a cylindrical tube modify the transmission coefficient ( S ₂₁ ) and resonance frequency ( f _r ) of the SCSRR. The method utilizes a microwave frequency in the range of 1.0-1.2 GHz with different sample concentrations ranging from 0 to 1 mg/ml. The change of electromagnetic properties can be used to monitor the phosphate, nitrate, and mixed phosphate and nitrate concentrations. Principle component analysis (PCA) is used for sample classification. This chemical sensing concept is potentially useful in biochemistry, medicine, agriculture, and the environment.