Exergoeconomic (Thermoeconomic) Analysis and Performance Assessment of a Gas Engine–Driven Heat Pump Drying System Based on Experimental Data

Exergoeconomic analysis has been used as a powerful tool to study and optimize various types of energy-related systems. In this study, we use the specific exergy cost (SPECO) method to calculate exergy-related parameters and display cost flows for all streams and components in a gas engine–driven heat pump drying system based on the experimental data. We analyze and evaluate the performance of the drying system components and the drying process for three different medicinal and aromatic plants from an exergoeconomic point of view. We also investigate the effect of varying dead (reference) state temperatures on exergoeconomic performance parameters for the drying system components and drying process. Although the condenser and drying chamber of the gas engine–driven heat pump dryer were significantly affected by the ambient temperature, the gas engine was slightly influenced by the ambient temperature. At low ambient temperatures, the exergy rates increased and the most effective performance obtained from this dryer was at 0°C. The performance of the drying process also increased at low ambient temperatures. This study demonstrated that exergoeconomic analysis can provide more information than exergy analysis, and the results obtained from the exergoeconomic analysis provided cost-based information, suggesting potential locations for drying system improvement.     

Arsenic removal from drinking water by electrocoagulation using iron electrodes

Arsenic removal from drinking water was investigated using electrocoagulation (EC) followed by filtration. A sand filter was used to remove flocs generated in the EC process. Experiments were performed in a batch electrochemical reactor using iron electrodes with monopolar parallel electrode connection mode to assess their efficiency. The effects of several operating parameters on arsenic removal such as current density (1.5–9.0 mA cm^?2), initial arsenic concentration (50–500 μg L^?1), operating time (0–15 min), electrode surface area (266–665 cm²), and sodium chloride concentrations (0.01 and 0.02M) were examined. The EC process was able to decrease the residual arsenic concentration to less than 10 μg L^?1. Optimum operating conditions were determined as an operating time of 5 min and current density of 4.5 mA cm^?2 at pH of 7. The optimum electrode surface area for arsenic removal was found to be 266 cm² taking into consideration cost effectiveness. The residual iron concentration increased with increasing residence time, and maximum residual iron value was measured as 287 μg L^?1 for electrode surface area of 266 cm². The addition of sodium chloride had no significant effect on residual arsenic concentration, but an increase in current density was observed.     

Laser speckle reduction via TiO2-sapphire composite rotating wheel in laser projection

Laser sources have been considered to be better light sources compared to traditional lamps or light-emitting diodes used in projectors, which enables the projector to create images with higher color saturation, brightness, and energy efficiency. However, the speckle noise caused by the coherent nature of the laser is a major technology obstacle for laser projection, which severely affects the image quality. To suppress laser speckle, a TiO₂-sapphire composite (TSC) with rough and high reflectivity surface and high thermal conductivity substrate is designed, which reduces the laser speckle by creating spatial diversity. Moreover, combined with a micro motor, the design and fabrication of the TSC rotating wheel are realized, which further reduces the laser speckle by creating time diversity. The experimental results show that the laser speckle contrast can be reduced from 9.0% to 2.2% when placing the TSC rotating wheel in the light path, which is below the speckle perception limit of the human eye (<4%). This new type of laser speckle suppression device is simple to use, low in cost, high in energy utilization, high in thermal conductivity, easy to mass production, and has great application potential in high-power laser projection.     

Influence of Sliding Rate and Load with Friction on NiTi Shape Memory Alloy Wear Resistance

Metal Science and Heat Treatment - The effect of load and sliding rate on wear resistance of a NiTi alloy in martensitic and austenitic conditions with dry friction by a ball–disk scheme is...     

Analysis of Microstructures and Mechanical Properties of Particle Reinforced AlSi7Mg2 Matrix Composite Materials

The present study examined the microstructures and mechanical properties (tensile and impact strength, hardness) of selected metal matrix composite materials. SiCp reinforced AlSi7Mg2 matrix composites were produced using gravity and squeeze casting methods and subsequently T6 heat treated. Some of the squeeze casted composites were shaped by extrusion. The extrusion generated an equiaxed matrix structure and SiCp caused a homogeneous distribution. The quasi absence of porosity in the squeeze casted composites led to improved mechanical properties. Whereas an increase in the SiCp ratio resulted in an increase of the tensile strength, it led to a decrease of the impact strength values. The enhancement of the mechanical properties following an applied heat treatment was better for materials shaped by extrusion.     

In situ investigation of surfactants’ effect onto electrochemical synthesis and properties of polyfurans

Polyfuran (PFu) films were electrochemically deposited onto gold electro-quartz crystal microbalance (EQCM) electrodes using acetonitrile (ACN)/LiClO₄ solvent-electrolyte in presence of dodecylbenzenesulfonic acid (anionic, DBSA) and polyethylene glycol sorbitan monolaurate (non-ionic, Tween 20) surfactants. The effect of surfactants on structural and conductivity properties of the polymer films was investigated using Fourier transform-infrared spectroscopy (FT-IR) and four-probe conductivity measurements. The doping effects of surfactants onto the properties of PFu were correlated with mass gain using in situ EQCM. The conductivity of PFu polymer was measured for PFu with no surfactant and for PFu in presence of two surfactants (Tween 20 and DBSA). Our data indicate that although a fast polymerization, a sharp shift in the frequency and mass changes of the polymer films as well as the highest recorded conductivity of 0.048 S cm^?1 were all obtained for the PFu/Tween 20-2 sample, significantly more PFu films formed with PFu/DBSA than with PFu/Tween 20 samples. We concluded that more PFu films can be obtained when an oxidant and an anionic surfactant (DBSA) are used than when an oxidant is used alone, or when an oxidant is used with a non-ionic surfactant (Tween 20). A part of an anionic surfactant can be incorporated into a PFu structure like an oxidant anion and can act as co-dopant.     

Poly(hydroxyethyl methacrylate-co-methacryloylamidotryptophane) nanospheres and their utilization as affinity adsorbents for porcine pancreas lipase adsorption

Novel nanospheres with an average size of 350 nm utilizing N-methacryloyl-(l)-tryptophane methyl ester (MATrp) as a hydrophobic monomer were prepared by surfactant free emulsion polymerization of 2-hydroxyethyl methacrylate (HEMA), (MATrp) conducted in an aqueous dispersion medium. MATrp was synthesized using methacryloyl chloride and (l)-tryptophane methyl ester. Specific surface area of the non-porous nanospheres was found to be 1902.3 m²/g. poly(HEMA–MATrp) nanospheres were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and scanning electron microscopy (SEM). Average particle size and size distribution measurements were also performed. Elemental analysis of MATrp for nitrogen was estimated at 1.36 mmol/g nanospheres. Then, poly(HEMA–MATrp) nanospheres were used in the adsorption of porcine pancreas lipase in a batch system. Using an optimized adsorption protocol, a very high loading of 558 mg enzyme/g nanospheres was obtained. The adsorption phenomena appeared to follow a typical Langmuir isotherm. The K_m value for immobilized lipase (16.26 mM) was higher than that of free enzyme (10.34 mM). It was observed that enzyme could be repeatedly adsorbed and desorbed without significant loss in adsorption amount or enzyme activity. These findings show considerable promise for this material as an adsorption matrix in industrial processes.     

An Empirical Comparison of Search Approaches for Moving Agents

This study empirically compares existing search approaches used for path planning of moving agents, namely, incremental and real‐time search approaches. The comparisons are performed in both stationary and moving target search problems separately. In each problem domain, well‐known representatives of both approaches are evaluated in partially observable environments where the agent senses a limited area based on its sensor range. In addition to the available algorithms, we propose two algorithms to be used in each problem. The simulations conducted on random grid and maze structures show that the algorithms behave differently and have advantages over each other especially as the sensor range varies. Therefore, the proposed study enables the agent to determine the most appropriate algorithm depending on its priorities and sensor range.     

Synthesis,physical properties,and application of aminated poly(glycidyl methacrylate)/zeolite composite

Poly(glycidyl methacrylate)/zeolite (PGMA/Z) composite was prepared by free radical polymerization and it was further modified to contain amino groups on its surface, by reacting to hexamethylenediamine. FTIR, TG, and SEM analyses were performed and investigated its potential as an adsorbent for removal of anionic dyes; namely, Reactive Red 120 (RR120) and Reactive Blue 4 (RB4). The effect of operational parameters was investigated. Maximum RR120 and RB4 adsorption capacities of composite were calculated as 136.5 and 189.8 mg g⁻¹, respectively. Isotherm, kinetic, and thermodynamic studies were also performed. It was found that the adsorption process might be heterogeneous by nature, and adsorption kinetics of reactive dyes followed the pseudo‐second order. The thermodynamic calculations showed that adsorption process was spontaneous and exothermic. POLYM. COMPOS., 37:2313–2322, 2016. © 2015 Society of Plastics Engineers     

Electrochromic properties of some bis‐chalcone derivatives‐based nanofibers

Two bis‐chalcone derivatives, (2E,6E)‐2,6‐bis[(thiophen‐2‐yl)methylene]cyclohexanone ( C1 ) and (2E,6E)‐2,6‐bis[(furan‐2‐yl)methylene]cyclohexanone ( C2 )‐based electrochromic (EC) nanofibers were produced in the presence of poly(methyl methacrylate) (PMMA) as supporting polymer using the electrospinning technique. The scanning electron microscopy (SEM) and energy dispersive X‐ray spectroscopy were used to examine morphology and chemical compositions of nanofibers before and after stability test. SEM images of the obtained smooth and bead‐free nanofibers before the stability test showed that both bis‐chalcone derivatives were homogeneously dispersed on the surface of the electrospun nanofibers. Nanofibers of bis‐chalcone derivatives were characterized with Fourier‐transform infrared spectroscopy. The electrochemical and EC properties of these bis‐chalcone derivatives were investigated. The C1 ‐PMMA nanofiber‐based electrochromic device (ECD) showed higher ΔT_max (41.47%) than that of the C2 ‐PMMA nanofiber‐based ECD (4.67%) during coloration/bleaching at 715 nm. The switching times for coloration and bleaching of C1 ‐PMMA nanofiber‐based ECD were found to be 4.42 and 1.12 s, respectively, and the coloration efficiency was 136.18 cm²/C. Repeated cyclic voltammograms and 1000 cycles of chronoamperometric measurements of the bis‐chalcone derivatives indicated that ECDs have long‐term redox stability. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46010.