Impact of independent and non-independent parameters on various elements’ rejection by nanofiltration employed in groundwater treatment

Nanofiltration is one of the widely used robust methods in water sweetening throughout the world. This work highlights the comparison of the impact of independent and non-independent parameters on element rejection to treat groundwater of a region located in Qazvin province, Iran. A pilot-scale FILMTEC-NF90-4040 nanofilter membrane was applied. Samples were collected from three various wells and the volume of 50 cc was tested, each of which was tested three times, and then cations and anions were measured in raw water and treated water by ion chromatography. The data collection and operation of the system was performed by the 761 compact IC version 1.1 software where statistical analyses were performed with SPSS, version 19. Results showed that the degradation efficiency of divalent ions was greater than that of monovalent cations. The content of ion rejection in the nanofilter membrane was not an independent phenomenon. For instance, the results revealed that the presence of high magnesium ion is very effective in disposing sodium ion. At the same time, the rejection rate of ions does not always follow the Van’t Hoff series. Optimal pressure was determined to be 10 bar

An intelligent energy management strategy for an off-road plug-in hybrid electric tractor based on farm operation recognition

Abstract Due to the growing emergence of vehicle electrification, agricultural tractor developers are launching hybrid powertrains in which energy management strategy (EMS) assumes a prominent role. This work mainly aims at developing an EMS for a plug-in hybrid electric tractor (PHET) to minimise fuel consumption and increase the operating range. The developed off-road PHET power sources are composed of a biogas-fuelled Internal Combustion Engine Generator (Bio-Gen), a photovoltaic system, and a battery pack. To control the power flow among different sources, a two-layer EMS is formulated. In this regard, initially, the farm operating mode is recognised by means of classification of a working cycle's features. Then, a control strategy based on a multi-mode fuzzy logic controller (MFLC) is employed to manage the power flow. At each sequence, the classifier identifies the farm operation condition and accordingly activates the relative mode of the MFLC to meet the requested power from the Bio-Gen. The performance of the proposed EMS has been evaluated based on three real-world typical agricultural working cycles. The results demonstrate the successful performance of the proposed intelligent EMS under farm conditions by maintaining the energy sources' operation in a high-efficiency zone which can lead to the extension of the working range and decrease fuel consumption

The treatment of printing and packaging wastewater by electrocoagulation– flotation: the simultaneous efficacy of critical parameters and economics

In this work, electrocoagulation–flotation (ECF) following sedimentation was applied as a printing and packaging wastewater treatment using four Al electrodes with a parallel monopolar configuration. A sedimentation process was applied after the ECF as a post-treatment phase to remove large pollutants. The simultaneous efficacy of the operating parameters initial color content (1,843.44–12,156.56 ADMI), initial pH (3.56–10.44), current density (6.02–22.18 mA/cm2), and treatment time (5.62–74.38 min) on color and chemical oxygen demand (COD) removal efficiencies were evaluated alongside processing costs. Response surface methodology (RSM) and central composite design (CCD) optimized these key parameters to achieve the highest removal efficiencies and lowest operating costs. Based on the results analyzed by RSM-CCD, using initial color content of 5,576.38 ADMI, initial pH of 7.29, the current density of 18.49 mA/cm2, and treatment time of 59.76 min as optimum operational conditions can result in 97.8% and 92.1% for color and COD removal efficiencies, respectively. At these optimum conditions, operating costs (OPCs), including electrodes material and energy consumption, were 0.07 US$/(kg color removed) and 0.4 US$/(kg COD removed). The results confirm ECF-sedimentation as a promising and costeffective tool for the treatment of printing and packaging wastewater

Liveness verification in trss using tree automata and termination analysis

This paper considers verification of the liveness property Live(.R, I, G) for a term rewrite system (TRS) R, where I (Initial states) and G (Good states) are two sets of ground terms represented by finite tree automata. Considering I and G, we transform R to a new TRS R' such that termination of R' proves the property Live(R,I,G)

Application of acceptance probability approach for determination of optimal rain gauge network density (Case study: South Khorasan province)

For accurate estimation of rainfall, as a key element in agricultural and water balance studies, an optimum density of raingauges is required. Although many approaches based on geostatistic are developed to optimize raingauges network, but majority of them suffer from drawbacks. This study aimed to assess a newly developed method in geostatistic based on acceptance probability, for designing the raingauge network with least error in South Khorasan province. The linear moment method was used for testing the homogeneity of the study stations. Then, by choosing a suitable semi-variogram, the acceptance probability in the region was calculated. Based on the spatial pattern of annual rainfall, the acceptance probability was worked out for various parts of the province and the acceptance accuracy (AP) values were analyzed at different levels of probability. The results showed that 20 stations of existing network had no significant effect on estimating the rainfall and it can be recommended to shift their location in order to obtain an optimal network. Also, similar to the existing network of 63 stations, the remaining 43 stations could cover 36% of the province at the probability acceptance level of 80%. Besides, the results indicated that by adding 27 rain gauges to the locations specified in the optimal density, the performance of the optimized network will be approximately doubled comparing to previously existing one, which means 65% coverage of province

Sol–gel processed pyridinium ionic liquid-modified silica as a new sorbent for separation and quantification of iron in water samples

1-Hexylpyridinium hexafluorophosphate [C6py][PF6] ionic liquid (IL) was firstly used for chemical modification of silica utilizing the acid-catalyzed sol–gel processing. The obtained pyridinium IL-modified silica was employed as a solid phase extraction (SPE) sorbent for removal of trace levels of Fe(III) ions from aqueous samples. The influence of different variables on the separation efficiency, including the concentration of chelating agent, pH, sample flow rate and volume, eluent type, concentration and volume, and interfering ions was investigated by flame atomic absorption spectrometry (FAAS). In the optimum experimental conditions, the limit of detection (3s), limit of quantification (LOQ) and pre-concentration factor were 0.7 μg L−1, 2.5 μg L−1, and 200, respectively. The relative standard deviation (RSD) for nine replicate determinations of 25 μg L−1 Fe was 3.2%. The calibration graph using the pre-concentration system was linear in the range of 2.5–50 μg L−1 with a correlation coefficient of 0.9997. The developed method was validated by the analysis of certified reference material and applied successfully to the separation and determination of iron in several water samples