Energy,Exergy, Exergoeconomic and Exergoenvironmental Impact Analyses and Optimization of Various Geothermal Power Cycle Configurations

Energy, exergy, and exergoeconomic evaluations of various geothermal configurations are reported. The main operational and economic parameters of the cycles are evaluated and compared. Multi-objective optimization of the cycles is conducted using the artificial bee colony algorithm. A sensitivity assessment is carried out on the effect of production well temperature variation on system performance from energy and economic perspectives. The results show that the flash-binary cycle has the highest thermal and exergy efficiencies, at 15.6% and 64.3%, respectively. The highest generated power cost and pay-back period are attributable to the simple organic Rankine cycle (ORC). Raising the well-temperature can increase the exergy destruction rate in all configurations. However, the electricity cost and pay-back period decrease. Based on the results, in all cases, the exergoenvironmental impact improvement factor decreases, and the temperature rises. The exergy destruction ratio and efficiency of all components for each configuration are calculated and compared. It is found that, at the optimum state, the exergy efficiencies of the simple organic Rankine cycle, single flash, double flash, and flash-binary cycles respectively are 14.7%, 14.4%, 12.6%, and 14.1% higher than their relevant base cases, while the pay-back periods are 10.6%, 1.5% 1.4%, and 0.6% lower than the base cases.     

Design and Implementation of a Bandpass–Bandpass Diplexer Using Coupled Structures

Wireless Personal Communications - In this paper, a bandpass–bandpass two channels diplexer with operating frequencies of 1.7 GHz and 2.1 GHz is designed and fabricated on RT/duroid...     

Investigation of the formation of acid rain based on the sulfur tetroxide (SO4 (C2v)) and OH radical reaction

Structural Chemistry - The reaction pathways of sulfur tetroxide (SO4 (C2v)) with OH radical have been investigated at the MP2/6-31++G(d,p) and G3MP2B3 levels. The mechanism I (Transfer of O-atom...     

The performance assessment of nanofluid-based PVTs with and without transparent glass cover: outdoor experimental study with thermodynamics analysis

Journal of Thermal Analysis and Calorimetry - The main objective of current work is to scrutinize the performance of unglazed photovoltaic thermal system (PVTs) and transparent glazed photovoltaic...     

A computational investigation on the potential energy surface of thiosulfeno with O(3P) reaction

The reaction paths of thiosulfeno radical (HS₂) with O(³P) have been investigated at the UB3LYP/aug-cc-pV(T + d)Z and UCCSD(T)/aug-cc-pV(T + d)Z//B3LYP levels. Two stable collision intermediates, HSSO and SS(H)O, have been considered for the HS₂ + O(³P) reaction. Four products of S + HSO, H + SSO, HS + SO, and S₂ + OH are obtained by starting from HSSO and SS(H)O. The calculated results show that the most feasible paths for the formation of S + HSO, H + SSO, and HS + SO products include no transition states in reaction path, while that of S₂ + OH product includes relatively high energy barriers of 23.0 kcal/mol. Therefore, S + HSO, H + SSO, and HS + SO are main products (with the stability other of HS + SO > H + SSO > S + HSO) and S₂ + OH is the second product in HS₂ + O(³P) reaction. Because, all intermediates, transition states, and products involved in the reaction paths lie below the initial reactants, the HS₂ + O(³P) reaction is expected to be rapid even at low temperatures.     

Synthesis and Characterization of Carbon-Stabilized Magnesium Nanoparticles

Magnesium nanopowder has attracted many interests in the recent years, which has a very difficult and costly synthesis process because of its high activity. In this work, magnesium nanoparticles stabilized with amorphous carbon (Mg–C nanoparticles) were synthesized by submerged arc discharge technique in kerosene. The arc discharge was generated between two electrodes of magnesium at the arc current of 1 A and arc voltage of 50 V. Mg–C nanoparticles were characterized by various techniques. Dynamic light scattering result indicated that size of magnesium nanoparticles is about 35 nm. X-ray diffraction showed that the produced sample consisted of hexagonal magnesium and amorphous carbon and there was no presence of magnesium oxides in the pattern. Field emission scanning electron microscopy and transmission electron microscopy results illustrated that the sample has morphology of agglomerated nanospheres. Energy dispersive X-ray spectroscopy demonstrated formation of 57 percent magnesium and 43 percent carbon. Differential scanning calorimetry analysis showed that the amorphous carbon increased ignition temperature of nanoparticles by 180 °C compared to pure magnesium micron-sized powder. Therefore, Mg–C nanoparticles can have many applications in different fields similar to magnesium nanopowders. However, by producing Mg–C nanoparticles, there is no need for vacuum chamber or inert gases during production and after that, since amorphous carbon protects magnesium nanoparticles from oxidation.     

CogNS: A Simulation Framework for Cognitive Radio Networks

Cognitive radio technology has been used to efficiently utilize the spectrum in wireless networks. Although many research studies have been done recently in the area of cognitive radio networks (CRNs), little effort has been made to propose a simulation framework for CRNs. In this paper, a simulation framework based on NS2 (CogNS) for cognitive radio networks is proposed. This framework can be used to investigate and evaluate the impact of lower layers, i.e., MAC and physical layer, on the transport and network layers protocols. Due to the importance of packet drop probability, end-to-end delay and throughput as QoS requirements in real-time reliable applications, these metrics are evaluated over CRNs through CogNS framework. Our simulations demonstrate that the design of new network and transport layer protocols over CRNs should be considered based on CR-related parameters such as activity model of primary users, sensing time and frequency.     

Two Reliable Simple Relationships between Flash Points of Hydrocarbon Kerosene Fuels and Their Molecular Structures

This study presents two new reliable simple correlations for predicting flash point of kerosene hydrocarbons using multiple linear regression method. The methodology assumes that the flash point of kerosene fuels can be expressed as a function of elemental composition and several structural parameters. The proposed correlations have determination coefficients of 0.910 and 0.977. Also, the first model has root mean square deviation (RMSD) and the average absolute deviations (AAD) of 10.6 and 8.2 K, respectively, for 111 kerosene fuels with different molecular structures as training set. The RMSD and AAD for the second improved model are 5.39 and 4.33 K, respectively. The predictive power of two correlations is checked using a cross validation method. (R² = 0.977, Q²_Ext = 0.975, and Q²_LMO = 0.979). Also, these correlations give good predictions for further 25 kerosene fuels as test set. The proposed model can also be applied for designing novel kerosene fuels.     

On‐line determination of sarcosine in biological fluids utilizing dummy molecularly imprinted polymers in microextraction by packed sorbent

Several years ago, sarcosine received attention as a prostate‐cancer marker. Prostate cancer is one of the most widespread types of tumor diseases in men. The prostate‐specific antigen is normally used as a marker, and it can only be detected in blood with a sensitivity of approximately 80%. In the present study, dummy molecularly imprinted polymers in microextraction by packed sorbent with on‐line liquid chromatography coupled to tandem mass spectrometry was used for the determination of sarcosine in human plasma and urine samples. The polymer network glycine was used for the dummy molecularly imprinted polymers. The selectivity of the method was evaluated using similar prostate‐cancer biomarkers. In addition, various parameters affecting the extraction performance were investigated. The method limits of detection and quantification in the plasma and urine were 1.0 and 3.0 ng/mL, respectively. The values of the coefficient of determination were over 0.99 for all runs in the studied concentration range (3.0–10 000 ng/mL). The method recovery was 87 and 89% in plasma and urine, respectively. The intraday and interday precisions of sarcosine in the plasma and urine samples were in the ranges of 4.0–7.1, 3.0–6.3, 2.9–4.7, and 5.0–6.7, respectively.     

Activated nitriles in heterocyclic synthesis: Synthesis of 6-thiophen-2-yl and 6-furan-2-ylthiazolo[2,3—a]pyridine derivatives

A variety of new 6-thiophen-2-yl and 6-furan-2-ylthiazolo[2,3—a]pyridine derivatives could be prepared via the reaction of 2-functionally substituted methyl-2-thiazolin-4-one with cyanomethylenethiophen-2-yl and cyanomethylenefuran-2-yl derivatives. The structure of the reaction products was established based on spectral data.

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Aktivierte Nitrile in der Heterocyclen-Synthese: Die Synthese von 6-Thiophen-2-yl-und 6-Furan-2-yl-thiazolo[2,3—a]pyridin-Derivaten

Zusammenfassung Es konnte eine Reihe neuer 6-Thiophen-2-yl- und 6-Furan-2-yl-thiazolo-[2,3—a]pyridine über die Reaktion von 2-funktionell-substituierten Methyl-2-thiazolin-4-onen mit Cyanomethylenthiphen-2-yl bzw. Cyanomethylenfuran-2-yl-Derivaten hergestellt werden. Die Struktur der Reaktionsprodukte wurde mit spektroskopischen Methoden ermittelt.