•A novel optimization procedure for photovoltaic water pumping systems for irrigation is proposed.•An hourly simulation model is the basis of the optimization procedure.•The effectiveness of the new ...optimization approach has been tested to an existing photovoltaic water pumping system.
Photovoltaic water pumping technology is considered as a sustainable and economical solution to provide water for irrigation, which can halt grassland degradation and promote farmland conservation in China. The appropriate design and operation significantly depend on the available solar irradiation, crop water demand, water resources and the corresponding benefit from the crop sale. In this work, a novel optimization procedure is proposed, which takes into consideration not only the availability of groundwater resources and the effect of water supply on crop yield, but also the investment cost of photovoltaic water pumping system and the revenue from crop sale. A simulation model, which combines the dynamics of photovoltaic water pumping system, groundwater level, water supply, crop water demand and crop yield, is employed during the optimization. To prove the effectiveness of the new optimization approach, it has been applied to an existing photovoltaic water pumping system. Results show that the optimal configuration can guarantee continuous operations and lead to a substantial reduction of photovoltaic array size and consequently of the investment capital cost and the payback period. Sensitivity studies have been conducted to investigate the impacts of the prices of photovoltaic modules and forage on the optimization. Results show that the water resource is a determinant factor.
This paper proposes new algorithms for the assembly line balancing problem with hierarchical worker assignment (ALBHW). The ALBHW appears in real industrial contexts, where companies deal with a ...multi-skilled workforce. It considers task execution times that vary depending on the worker type to whom the task is assigned. Qualification levels among workers are ranked hierarchically, where a lower qualified worker costs less but requires larger execution times then a higher qualified one. The aim is to assign workers and tasks to the stations of an assembly line, in such a way that cycle time and precedence constraints are satisfied, and the total cost is minimised. In this paper, we first present a mathematical model and improve it with preprocessing techniques. Then, we propose a constructive heuristic and a variable neighbourhood descent that are useful to solve large instances. Extensive computational experiments on benchmark instances prove the effectiveness of the algorithms.
Chitosan-based thin films were assembled using the layer-by-layer technique, and the axial composition was accessed using X-ray photoelectron spectroscopy with depth profiling. Chitosan (CHI) samples ...possessing different degrees of acetylation ( D A ̅ ) and molecular weight ( M v ̅ ) produced via the ultrasound-assisted deacetylation reaction were used in this study along with two different polyanions, namely, sodium polystyrenesulfonate (PSS) and carboxymethylcellulose (CMC). When chitosan, a positively charged polymer in aqueous acid medium, was combined with a strong polyanion (PSS), the total positive charge of chitosan, directly related to its D A ̅ , was the key factor affecting the film formation. However, for CMC/CHI films, the pH of the medium and M v ̅ of chitosan strongly affected the film structure and composition. Consequently, the structure and the axial composition of chitosan-based films can be finely adjusted by choosing the polyanion and defining the chitosan to be used according to its DA and M v ̅ for the desired application, as demonstrated by the antibacterial tests.
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•A new 3,6-O,O’- dimyristoyl chitosan (DMC) derivative was synthesized and characterized.•DMC micelles were obtained and promoted PTX solubilization.•The derivative polymer and DMC ...micelles presented good biocompatibility in cytotoxicity studies.•The drug in vitro permeability was evaluated in different cell models.
The aim of the present study was to investigate the potential application of 3,6-O,O’- dimyristoyl chitosan DMCh, an amphiphilic derivative of chitosan, for improving the oral bioavailability of paclitaxel (PTX), a water insoluble anticancer drug. The O-acylation of chitosan with myristoyl chloride was carried out by employing high (≈13.3) or low (2.0) molar excess of chitosan to result in samples DMCh07 and DMCh12, respectively. The successful O-acylation of chitosan was confirmed by FTIR and 1H NMR spectroscopy, the latter allowing also the determination of average degree of substitution (DS). The critical aggregation concentration (CAC) of samples DMCh07 (DS≈6.8%) and DMCh12 (DS≈12.0%) were 8.9×10−3mg/mL and 13.2×103mg/mL, respectively. It was observed by TEM that the DMCh micelles showed spherical shape while DLS measurements allowed the determination of their average size (287nm–490nm) and zeta potential (+32mV to +44mV). Such DMCh micelles were able to encapsulate paclitaxel with high drug encapsulation efficiency (EE), as confirmed by HPLC analyses. Studies on the cytotoxicity of DMCh07 micelles toward Caco-2 and HT29-MTX cells showed that, regardless the PTX loaded, DMCh07 micelles slightly decreased cellular viability at low micelles concentration (≤1μg/mL) while at high concentration (>10μg/mL) PTX-loaded DMCh07 micelles were less toxic toward Caco-2 cells when compared to free PTX. The PTX permeation across Caco-2 monoculture and Caco-2/HT29-MTX co-culture model confirmed the potential of DMCh micelles in improving the intestinal absorption of PTX. These results suggest that DMCh micelles may be a promising carrier to encapsulate PTX aiming cancer therapy.
The development and application of a functionalized carbon nanotubes paste electrode (CNPE) modified with crosslinked chitosan for determination of Cu(II) in industrial wastewater, natural water and ...human urine samples by linear scan anodic stripping voltammetry (LSASV) are described. Different electrodes were constructed using chitosan and chitosan crosslinked with glutaraldehyde (CTS-GA) and epichlorohydrin (CTS-ECH). The best voltammetric response for Cu(II) was obtained with a paste composition of 65% (m/m) of functionalized carbon nanotubes, 15% (m/m) of CTS-ECH, and 20% (m/m) of mineral oil using a solution of 0.05
mol
L
−1 KNO
3 with pH adjusted to 2.25 with HNO
3, an accumulation potential of −0.3
V
vs. Ag/AgCl (3.0
mol
L
−1 KCl) for 300
s and a scan rate of 100
mV
s
−1. Under these optimal experimental conditions, the voltammetric response was linearly dependent on the Cu(II) concentration in the range from 7.90
×
10
−8 to 1.60
×
10
−5
mol
L
−1 with a detection limit of 1.00
×
10
−8
mol
L
−1. The samples analyses were evaluated using the proposed sensor and a good recovery of Cu(II) was obtained with results in the range from 98.0% to 104%. The analysis of industrial wastewater, natural water and human urine samples obtained using the proposed CNPE modified with CTS-ECH electrode and those obtained using a comparative method are in agreement at the 95% confidence level.
Recently the squid pens, a rich source of β-chitin containing low contents of inorganic compounds, have become available in considerable amounts as a refuse of the fishery industries in Brazil. Thus, ...the aim of this work is to use squid pens from
Loligo sanpaulensis and
Loligo plei, species found in the Brazilian coast, as the raw material for the extraction of β-chitin. The squid pens were submitted to the usual sequence of treatments used for chitin extraction – demineralization and deproteinization – but due to its low content of inorganic compounds a two-step alkaline treatment was enough to produce β-chitin with low contents of ash (⩽0.7%). Indeed, the low contents of ash and metals, such as Ca (⩽10.4
ppm), Mg (⩽2.5
ppm), Mn (⩽3.1
ppm) and Fe (⩽1.8
ppm), are lower than those reported in most of the papers found in the literature. Also, the β-chitin extracted by employing only the alkaline treatment was more acetylated than the other samples prepared in this work. Regardless of the treatment employed for the extraction of the β-chitin from the squid pens, its infrared spectra and X-ray diffraction pattern presented only minor differences, however they were clearly distinguished from commercial α-chitin.
Abstract
The Italian Minister for University and Research has recently funded a large program for an Innovative Research Infrastructure on applied Superconductivity (IRIS) in Italy. Based on the LASA ...laboratory in Milan, it is a partnership, in the form of a strongly coordinated work, of existing laboratories of various institutes: INFN (leader, participating with 4 labs: Frascati, Genoa, Milan, Salerno); CNR (SPIN institute in Genoa, Naples and Salerno); five Universities: Genoa, Milan, Naples, Salento and Salerno. IRIS will be an upgrade of existing infrastructures, with new state-of-the-art instruments, reinforcing the capability of Italy in the domain of superconductivity aimed to accelerators. IRIS foresees a strong coordination of the activity of the participating laboratories until 2035, at least, thus enhancing the participation of Italian laboratories to future projects requiring advanced superconducting technology, like FCC or the Muon-Collider, and also for developing societal applications of technologies, pursued for high-energy accelerators, especially for the energy domain and the medical sector. In this paper, we present the two novel demonstrators, part of the initial IRIS program: 1) a green superconducting line, 130 m long and designed for 40 kA current capability at 25 kV; 2) a 1 m long HTS dipole magnet with some characteristics similar to LHC dipoles: 10 T, 50 mm × 80 mm bore, but operating at 20 K rather than 1.9 K.
Multidrug-resistant bacteria represent a global health and economic burden that urgently calls for new technologies to combat bacterial antimicrobial resistance. Here, we developed novel ...nanocomposites (NCPs) based on chitosan that display different degrees of acetylation (DAs), and conjugated polymer cyano-substituted poly(p-phenylene vinylene) (CNPPV) as an alternative approach to inactivate Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria. Chitosan’s structure was confirmed through FT-Raman spectroscopy. Bactericidal and photobactericidal activities of NCPs were tested under dark and blue-light irradiation conditions, respectively. Hydrodynamic size and aqueous stability were determined by DLS, zeta potential (ZP) and time-domain NMR. TEM micrographs of NCPs were obtained, and their capacity of generating reactive oxygen species (ROS) under blue illumination was also characterized. Meaningful variations on ZP and relaxation time T2 confirmed successful physical attachment of chitosan/CNPPV. All NCPs exhibited a similar and shrunken spherical shape according to TEM. A lower DA is responsible for driving higher bactericidal performance alongside the synergistic effect from CNPPV, lower nanosized distribution profile and higher positive charged surface. ROS production was proportionally found in NCPs with and without CNPPV by decreasing the DA, leading to a remarkable photobactericidal effect under blue-light irradiation. Overall, our findings indicate that chitosan/CNPPV NCPs may constitute a valuable asset for the development of innovative strategies for inactivation and/or photoinactivation of bacteria.
This paper presents a simulation approach to enhance the performance of heuristics for multiproject scheduling. Unlike other heuristics available in the literature that use only one priority ...criterion for resource allocation, this paper proposes a structured way to sequentially apply more than one priority criterion for this purpose. By means of simulation, different feasible schedules are obtained to; therefore, increase the probability of finding the schedule with the shortest duration. The performance of this simulation approach was validated with the MPSPLib library, one of the most prominent libraries for resource-constrained multiproject scheduling. These results highlight the proposed method as a useful option for addressing limited time and resources in portfolio management.
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