Optimal placing and sizing of parking lots including different levels of charging stations in electric distribution networks

Background: Low emission, high efficiency, and convenience of using plug-in electric vehicles (PEVs) are considered as significant benefits of PEVs. However, installation of parking lots (PLs) in order to supply PEVs causes some financial and technical challenges for electric distribution networks. The changes in system reliability, power loss, voltage drop, and costs associated with the installation of PLs are considered as some of the aforementioned challenges. Therefore, optimal placing and sizing of PEV PLs including different levels of charging stations ((CS); slow, medium, and fast) are presented in this paper. Since PLs have the potential to exchange electricity by electric network, they can be taken into account as distributed generations (DGs) and their installation can be considered from the perspective of installation of DGs. An objective function including system reliability, power loss, voltage drop, and PL cost/revenue is proposed for the optimal planning. Results: Genetic algorithm is employed to solve the optimisation problem. Simulation is carried out on a 33-bus radial distribution network. For the planning purposes of PLs, three different levels of CSs (slow, medium, and fast) in PLs are considered. The effect of increasing the penetration of PEVs in PLs is also examined on planning the PLs. The effect of different dispatch times on the selection of different CS levels (slow, medium, and fast) is investigated as well. Furthermore, the effect of applying tariffs and incentives for the customers is analysed for the selection of CS levels. Finally, the effect and importance of combinations of the CSs with different levels are investigated.     

Omega-3 Polyunsaturated Fatty Acids Concentration Using Synthesized Poly-Vinylidene Fluoride (PVDF) Asymmetric Membranes

In this study, the performance of synthesized poly‐vinylidene fluoride (PVDF) membranes to concentrate ω3‐polyunsaturated fatty acids from lantern fish oil was evaluated. The PVDF membranes were prepared via the phase inversion method. The effect of coagulation bath temperatures (CBT: 0, 25 and 50 °C) on the morphology of the membranes and the ω3‐PUFA concentration process was examined and discussed. Scanning electron microscopy images showed that an increasing coagulation bath temperature (CBT) leads to a more porous structure in the membranes as well as a larger pore diameter. ω3‐PUFA concentration was evaluated at different pressures and temperatures, ranging from 3 to 5 bar and 20 to 40 °C, respectively. The PVDF membrane prepared at a CBT of 0 °C (M1) resulted in the best ω3‐PUFA concentration (40.4 %) at a pressure and temperature of 5 bar and 30 °C, respectively. Conversely, the PVDF membrane formed at CBT of 50 °C (M3) showed the highest oil flux. In addition, fouling analysis indicates that complete pore blocking was the predominant mechanism for the M1 membrane and intermediate pore blocking for the M2 and M3 membranes.     

Investigating the effect of PGA on physical and mechanical properties of electrospun PCL/PGA blend nanofibers

In the field of tissue engineering there is always a need for new engineered polymeric biomaterials which have ideal properties and functional customization. Unfortunately the demands for many biomedical applications need a set of properties that no polymers can fulfill. One method to satisfy these demands and providing desirable new biomaterials is by mixing two or more polymers. In this work, random nanofibrous blends of poly (ε‐caprolactone) (PCL) and polyglycolic acid (PGA) with various PCL/PGA compositions (100/0, 80/20, 65/35, 50/50, and 0/100) were fabricated by electrospinning method and characterized for soft‐tissue engineering applications. Physical, chemical, thermal, and mechanical properties of PCL/PGA blend nanofibers were measured by scanning electron microscopy (SEM), porosimetry, contact angle measurement, water uptake, attenuated total reflectance Fourier transform‐infrared spectroscopy (ATR‐FT‐IR), X‐ray diffraction (XRD), differential scanning calorimetric (DSC), dynamic mechanical thermal analysis (DMTA), and tensile measurements. Morphological characterization showed that the addition of PGA to PCL results in an increase in the average diameter of the nanofibers. According to these results, when the amount of PGA in the blend solution increased, the hydrophilicity and water uptake of the nanofibrous scaffolds increased concurrently, approaching those of PGA nanofibers. Differential scanning calorimetric studies showed that the PCL and PGA were miscible in the nanofibrous structure and the mechanical characterization under dry conditions showed that increasing PGA content results in a tremendous increase in the mechanical properties. In conclusion, the random nanofibrous PCL/PGA scaffold used in this study constitutes a promising material for soft‐tissue engineering. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

An offset cancellation technique for comparators using body-voltage trimming

A novel offset cancellation technique based on body-voltage trimming is presented to be used in the comparators employed in high-speed analog-to-digital converters (ADCs) such as Flash ADCs. The proposed offset cancellation is achieved by body-voltage adjustment using a low-power simple analog control feedback circuit without any additional capacitive loading at the comparator output or complicated digital calibration scheme. The accuracy of the proposed technique is higher than its digital calibration counterparts due to its analog nature. Simulation results in a 1.8?V 0.18???m CMOS technology show that using the proposed technique the standard deviation of the comparator offset is significantly reduced from 36.2 to 7.1?mV operating at 1?GHz with only 32???W of power dissipation in the offset cancellation circuit.     

Influence of Alumina Particles on Thermal Behavior of High Density Polyethylene (HDPE)

This study evaluated the effects of alumina (Al₂O₃) particles on thermal properties of High Density Polyethylene (HDPE). HDPE and HDPE/5, 10 & 15 wt% Al₂O₃ composites were prepared by compression molding. Differential scanning calorimetery (DSC) was used to analyze the thermal and crystallization behavior of the samples. The results indicated that the alumina particles affected the crystallization behavior of HDPE matrix, significantly. However, the DSC results showed that alumina content did not influence the melting temperature of HDPE in this composite. The results also showed that the incorporation of alumina particles caused the decrease of specific heat capacity coefficient and entropy.     

STUDIES OF IRANIAN HEAVY OILS PERTINENT TO RESERVOIR CONDITIONS FOR THEIR AUTO-IGNITION TO INITIATE FIRE FLOODING

In this work, the potential for the auto-ignition of Iranian heavy oil during in situ combustion (ISC) process conditions was studied. Kinetic studies were carried out using thermal analysis techniques. Effects of oxygen partial pressure, reservoir pressure, and clay on the auto-ignition condition were investigated. Based on the experimental results obtained, a kinetic equation was derived for each of the different oil samples in the presence of different sands. The effect of partial pressure of oxygen in the injected air showed that at atmospheric pressure, low temperature combustion (LTC) was initiated at 275°C. Also, enriching the injected air by oxygen lowers the initial LTC temperature by up to 50°C. ARC experiments were undertaken to extend the studies to reservoir pressure conditions (1300 psi). It was found that activation energy in the LTC region was lowered as a consequence. As a result, initiation of LTC commenced at 115°C when air was injected. The effect of clay as a catalyst was also studied, and it was found that the activation energy decreases considerably when clay is present in the system. Experiments in a high-pressure combustion tube showed that LTC was initiated in the temperature range 120°–150°C, which is in line with the results obtained in the ARC. Fire flooding was sustained during the combustion tube test.     

Effect of structural parameters of porous yarns and fabric on air permeability and moisture transfer of double-face woven fabrics

In this study, effect of fabric structural parameters of double-face woven fabrics including kind of porous yarn namely micro-porous yarn and hollow yarn, hole size of hollow yarn, percentage of these yarns in double-face woven fabric structure, and finally weft density on air permeability and moisture transfer of woven fabrics was evaluated. These yarns were produced by using water-soluble continuous polyvinyl alcohol filaments as core part for hollow yarns and as doubling yarn in micro-porous yarn. Results revealed the effect of kind of porous yarn, hole size of hollow yarn, and weft density on air permeability and moisture transfer of woven fabrics. The percentage of porous yarns as weft did not show obvious trend. Analysis of variance was used to study the effect of these variables on air permeability and moisture transfer of double-face woven fabrics statistically.     

Activated carbon nanofibers as an alternative cathode catalyst to platinum in a two-chamber microbial fuel cell

This paper evaluated the oxygen reduction reaction (ORR) in a microbial fuel cell (MFC) system by using chemically and physically activated electrospun carbon nanofibers (ACNFs) in an MFC and comparing their performance with that of plain carbon paper. The chemical and physical activation was carried out by KOH reagents and CO₂ gas to increase the electrode surface area and the catalytic activity. As a result, it was found that the MFC with the chemically activated carbon nanofibers (ACNFs) exhibited better catalytic activity than that of the physically activated ACNFs. Chemically ACNFs with 8 M KOH were found to be one of the most promising candidates for the ORR and could generate up to 3.17 times more power than that of the carbon paper. The ACNFs with 8 M KOH exhibited 78% more power generation than that of the physically activated ACNFs and exhibited 16% more power generation than the chemically activated ACNFs with 4 M KOH. The power per cost of ACNFs with 8 M KOH is 2.65 times greater than that of the traditionally used platinum cathode. Thus, ACNFs are a good alternative catalyst to Pt for MFCs.     

Loofa immobilized Bacillus sp. DSM 2523 as a whole cell biocatalyst for production of cyclodextrin glucanotransferase in an airlift reactor with a net draft tube

Cyclodextrin glucanotransferase (CGTase) production was studied using loofa-immobilized Bacillus sp. DSM 2523 and starch substrate. The bacterial cells from 2- and 4-day old cultures were used in the flask studies. Loofa and chitosan were added for cell immobilization and cell flocculation, respectively, and different treatments were considered according to the timing of their addition. The cell responses were evaluated for their degree of cell immobilization and level of CGTase activity. With the use of the selected treatment, testing was carried out in an airlift reactor with a net draft tube having specific geometric properties. The cell capacity for reusability also was examined. The production of CGTase was higher in the second cycle in the reactor operated at 0.25 vvm where the enzyme activity reaching 0.20?U/ml within 2?h. In the flask experiments, CGTase activity reached 0.23?U/ml after 19?h in the second cycle.     

Artificial Neural Network Modeling of the Deposition Rate of Lactose Powder in Spray Dryers

A spray dryer is the ideal equipment for the production of food powders because it can easily impart well-defined end product characteristics such as moisture content, particle size, porosity, and bulk density. Wall deposition of particles in spray dryers is a key processing problem and an understanding of wall deposition can guide the selection of operating conditions to minimize this problem. The stickiness of powders causes the deposition of particles on the wall. Operating parameters such as inlet air temperature and feed flow rate affect the air temperature and humidity inside the dryer, which together with the addition of drying aids can affect the stickiness and moisture content of the product and hence its deposition on the wall. In this article, an artificial neural network (ANN) method was used to model the effects of inlet air temperature, feed flow rate, and maltodextrin ratio on wall deposition flux and moisture content of lactose-rich products. An ANN trained by back-propagation algorithms was developed to predict two performance indices based on the three input variables. The results showed good agreement between predicted results using the ANN and the measured data taken under the same conditions. The optimum condition found by the ANN for minimum moisture content and minimum wall deposition rate for lactose-rich feed was inlet air temperature of 140°C, feed rate of 23 mL/min, and maltodextrin ratio of 45%. The ANN technology has been shown to be an excellent investigative and predictive tool for spray drying of lactose-rich products.