In this study, a mathematical model for predicting the response of a conductometric urea biosensor was developed and numerically simulated. The biosensor features a planar interdigitated electrode array with immobilized urease. The enzymatic hydrolysis of urea generates ionic products, such as ammonium (NH₄⁺)and bicarbonate (HCO3-) ions, altering the solution's electrical conductivity. To optimize the biosensor performance, key physicochemical processes were analyzed through numerical modeling and validated against experimental data, showing strong agreement. Simulations under varying conditions supported the experimental design, improved the analytical performance, and reduced the development costs. While previous studies have explored conductometric urea biosensors, few have addressed optimizations through numerical modeling. This study addresses this gap by examining the effects of temperature, pH, enzyme layer thickness, and CO2 concentration using the COMSOL Multiphysics software. The model accurately predicted conductivity variations across different urea concentrations, with optimal responses being observed at 37 °C, 5% CO2, pH 7.4, and an enzymatic zone length of 500 μm. These results offer valuable insights for enhancing the design and application of conductometric urea biosensors in biomedical and environmental fields.

Software has been developed using the MATLAB language to analyze laser diode having the architecture InGaAsP/InP .The cavity length of active region of multi quantum well semiconductor laser effect on threshold current, quantum efficiency and optical output power of InGaAsP/InP and separate confinement heterostructure (SCH) is investigated. High-speed communication systems, especially those that use optical fiber communication for high-speed data transmission, use lasers with a wavelength of 1.55 μm. here, the performance of changing the cavity length values of active region between 250 to 500 μm at room temperature is study in this work. The characteristics power–current (P–I)and related features, threshold current and slope efficiency have been investigated. The threshold current decreases with increase of cavity lengths because the carrier density in the quantum well is very high. This effect is particularly pronounced in the shortest cavity measured (250μm), we extractIth=6.25ma,αi=30mA and ηd=63%. These modifications show that our proposed structure is better compared to the GaInP/GaAs 5QW laser structure (Ith=360mA and ηd=51%).

In the present study, ultra-thin layer ZnS is inserted in the structure of standard solar cell between CdS buffer layer and CZTS absorber layer to represent the Second Phase (SP) often forms on the top of CZTS. The impact of this layer on the performance of CZTS solar cells is illustrated by the diverse results obtained by simulation using SCAPS-1D. The formation of ZnS on the CZTS surface has harmful effects on the solar cells parameters where the conversion efficiency (η) decreases by 2%. When varying thickness of ZnS SP of 2% to 20% corresponding of the total absorber layer the efficiency decreases by about 0.65%. The ZnS SP can deteriorate the photovoltaic power conversion efficiency from 10.2% to levels of 8.8%, depending on the material buffer layer and the thickness of ZnS SP. Using the ZnS as buffer layer mitigates harmful effects of the ZnS secondary phase forms on the top of CZTS absorber layer.