A Model for Identifying the Behavior of Alzheimer’s Disease Patients in Smart Homes

Wireless Personal Communications - In recent years, Smart Cities and Smart Homes have been studied as an important field of research. The design and construction of smart homes have flourished so...     

Effect of l-Histidine Substitution on Sol–Gel of Transition Metal Coordinated Poly Ethyleneimine: Synthesis and Biochemical Characterization

The study was aimed to investigate the effect of chemical modification of branched poly ethyleneimine (PEI) on chelation of transition metal ions (Me²⁺) including Zn²⁺, Cu²⁺ or Ni²⁺ and sol–gel conversion thereof. To modulate chelation property of PEI, imidazole moieties were introduced into the polymer backbone by carbodiimide chemistry at different molar ratios of fmoc-protected l-histidine. The synthesis was characterized by ¹H-NMR spectroscopy and size exclusion chromatography. Potentiometric titration of PEI/Me²⁺ aqueous dispersions showed formation of stable complexes at pH above 5 depending on the degree of l-histidine substitution. FT-IR spectroscopy showed the imidazole ring of l-histidine was involved in the coordination interactions between PEI and Me²⁺. Addition of Zn²⁺ to PEI solution induced sol–gel conversion at a critical molar ratio decreasing by a higher degree of l-histidine modification. The gelation process led to formation of stable globular nanostructures as confirmed by atomic force microscopy with projected mean diameters less than 200 nm. Cellular experiment showed that l-histidine substitution enhanced cyto-compatibility of PEI, moreover cytotoxicity decreased significantly upon coordination of Zn²⁺ with the polymers. Conclusively, the coordination complexes of Zn²⁺ and l-histidine substituted PEI could serve as a nano system for biomedical applications.     

Design of a 10 W high‐efficiency balanced power amplifier using a combination of load‐pull and load‐line methods for ISM band

In this article, a 10 W power amplifier has been designed and constructed at 2.4 GHz. The source and load‐pull impedance data published by the manufacturer at a nearby frequency of 2.5 GHz have been adopted to power match the transistor at the intended design frequency. For this purpose, the linear model of the GaN transistor has been derived from the S‐parameter data. The load‐line at the dependent current source plane and the impedance at the intrinsic gate‐source capacitance have been simulated in the presence of the source and load‐pull impedances at 2.5 GHz. The extracted impedances have been retained in the design of the power amplifier at 2.4 GHz. In a novel approach, the input and output matching circuits interacted with the linear model of the transistor to provide the same load‐line conditions at the virtual drain plane and the intrinsic gate‐source capacitance plane. In contrast to conventional load‐pull methods that give no information about the harmonic terminations, harmonic terminations can be easily controlled in this method. The insight into the transistor linear model allows the harmonic terminations at the virtual drain plane to be set to low values for proper class‐B operation.     

Environmental Assessment of a Wastewater System under Water demand management policies

Water demand management policies (WDMPs) are considered necessary for sustainable water supplies to affect urban water infrastructures from various aspects, which has less attention in previous studies. Hence, this study is focused on proposing a comprehensive novel approach to provide helpful insight for researchers and policy-makers towards the environmental effects of applying WDMPs on wastewater systems. The life cycle assessment (LCA) method assesses the environmental burdens of utilizing WDMPs in the operation stage of a real wastewater system in Baharestan city, Iran. A detailed inventory is considered, including maintenance of sewer pipelines, replacement of manhole covers, civil works, road rehabilitation, energy consumption, chemical usage, transportation, and air emissions of the WWCN and WWTP using SimaPro software. Results show that a significant part of the environmental impacts accounts for energy consumption, which has strong effects on most midpoint categories and has a great change in different scenarios. For example, energy’s impact on the global warming category is reduced from around 18.4 to 8.5 million kg CO₂ eq. from scenario 0 to scenario 4 with an average of 165.4 to 94 L/capita/day of wastewater production, respectively. Besides, the results demonstrate that the environmental effects driven by the WWTP are eightfold the corresponding WWCN’s impacts. Overall, the outcomes from the present study reveals that implementing WDMPs can lead to diminishing environmental impacts. For instance, reducing wastewater production up to 68% can decrease 18% of the WDMPs’ environmental impacts of the wastewater system in the operation stage.

     

Pseudo-operational matrix method for the solution of variable-order fractional partial integro-differential equations

The main purpose of this paper is to utilize the collocation method based on fractional Genocchi functions to approximate the solution of variable-order fractional partial integro-differential equations. In the beginning, the pseudo-operational matrix of integration and derivative has been presented. Then, using these matrices, the proposed equation has been reduced to an algebraic system. Error estimate for the presented technique is discussed and has been implemented the error algorithm on an example. At last, several examples have been illustrated to justify the accuracy and efficiency of the method.