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Sandwich composites stand out especially in the aerospace industry owing to their high strength-to-weight ratio, one of the most prominent factors for material selection. Polymeric foams as core material in sandwich composites are likely to prevent delamination between face sheets and core by augmenting the contact surface area, resulting from their closed-cell structure. Polymeric foam properties can be enhanced by adding nanomaterials such as carbon nanotubes (CNTs), however increased CNT content or the type of CNTs might arise critical problems such as agglomeration and irregular distribution of nanomaterials. Cellulose nanocrystals (CNCs) are claimed to be good candidates to prevent nanomaterial reinforcing related issues and further, their inclusion enables reinforcing of polymeric foams using an optimum CNT/CNC concentration. In this work, CNT/CNC reinforced polyurethane (PU) foam-cored sandwich composites were manufactured and characterized for the influence of nanomaterial addition on the mechanical properties with an aim to find the optimum nanomaterial content. 0.1 wt.% CNT, CNC, CNT/CNC (1:1), and CNT/CNC (1:2) reinforced PU foam-cored sandwich composites were subjected to simultaneous three-point bending tests and acoustic emission tests, one of the promising non-destructive testing methods enabling in-situ monitoring of the damage mechanisms to understand how damage evolves. The effects of these nanomaterial additives on damage mechanisms and the mechanical properties were examined thoroughly via both mechanical and morphological characterizations. The test results were found to be promising in terms of revealing how these reinforcements affect the retardation and/or elimination of damage mechanisms including core damage, face sheet-core debonding, matrix cracking, and fiber breakage in the sandwich composite structures. The results suggested that with the addition of 0.1 wt.% CNT, the mechanical properties of PU foam were increased; therefore, the ratio of AE signals related to fiber breakage and core damage were decreased because of the strengthened core material.

The failure of carbon fiber reinforced epoxy matrix composites has been attributed to different mechanisms involving tensile, compressive and shear failure of the fibers or the matrix. This researc...

Depositing carbon nanotubes (CNTs) into carbon fiber reinforced polymer composites (CFRPs) is challenging because of the need for complicated lab-scale processes and toxic chemical dispersants that makes conventional means of processing less compatible with existing industrial procedures for large-scale applications. In this work, a scalable supercritical CO2-assisted atomization technique is used to effectively deposit hybrid CNTs in CFRPs allowing them to boost their functionality and tailor the microstructure. Cellulose nanocrystals (CNCs) are utilized to create hybrid nanostructures with CNTs (CNC bonded CNT) that enables stabilization of CNTs in nontoxic media, i.e., water, and this promotes the scalability of the process. According to Zeta potential values, CNCs successfully stabilize CNTs in water suspension. Scanning electron microscopy (SEM) micrographs show hybrid CNC bonded CNTs are homogeneously dispersed on the carbon fiber surface. According to the in-situ bending test under the optical microscope, crack propagation is hindered by engineered hybrid CNT nanostructures in the modified CFRP whereas neat CFRP exhibits low crack growth resistance due to the uninterrupted crack propagation in the continuous epoxy matrix. Our results imply that this strategy probes the importance of new controlled manufacturing of hybrid nanostructures through evaporation‑induced self‑assembly of nanocolloidal droplets, and allows for tailoring of the desired properties of nanostructured composites.

The focus of this study is to investigate how to lightweight SMC composites for automotive applications without compromising their performance. This is accomplished by replacing, at least partially, the heaviest materials such as the glass fibers (GF) or calcium carbonate (CaCO3) with nanocellulose or nanoclays. In addition, the chopped glass fibers are replaced by glass fabric in order to better control the location and orientation of the glass fiber reinforcement and thus engineer the mechanical properties. Unsaturated polyester resin (UPR) is used as the resin, and a pilot scale sheet molding compounds (SMC) is used to make the SMC. The composites are made by stacking plies of SMC layers in a mold, after appropriate conditioning of the SMC, and compression molding. The properties of interest are the tensile and flexural modulus and strength according to the corresponding ASTM standards and the density of the composites. The void content is also determined using acid digestion and scanning electron microscopy. The main goal is to replace traditional chopped glass fibers (GF) used in SMC with unidirectional glass fabric coated with cellulose nanocrystals (CNC). The reasoning is to enhance properties with a better UPR/GF interface and controlled fiber orientation while reducing density. The glass fiber fabric is coated with nanocellulose using a scalable spraying technique that leads to homogeneous coatings. The four different glass fiber fabrics that were used in this study vary in CNC coating amount. To understand the effect of the nanocellulose, the glass fiber content of all composite formulations was kept constant at about 30 vol%. In addition, to determine the mechanical properties of the composites, the viscosity was verified for all formulations to ensure processability using the SMC pilot line. SEM micrographs show the quality of the CNC coating on the glass fiber fabric. Water uptake of all composites was also determined. The expected results address design, processing, and testing challenges, and successes and failures. The question to be addressed is whether CNC coated fabric is significantly advantageous for SMC compared to randomly oriented, chopped GF.

With the increase in the number of people exposed to anesthetic gases, there is a critical need to examine the prevalence of neurotoxic symptoms in these individuals using reliable tools. The aim of this study was to evaluate the psychometric characteristics of EUROQUEST questionnaire and to measure the rate of neurotoxic symptoms in the anesthesiology personnel.This research was a cross-sectional study. This study was a cross-sectional one. Participants included 404 personnel of the operating room in western Iran. EUROQUEST questionnaire was translated into Persian and used to measure the rate of neurotoxic symptoms. Reliability of the questionnaire was examined by Cronbach's alpha, while face and construct validities were evaluated using SPSS 16 (SPSS Inc., Chicago, IL, USA) and AMOS 18 (IBM, Chicago, IL, USA) software.The results indicated that EUROQUEST questionnaire had acceptable reliability and validity. The most prevalent symptoms were observed in memory and concentration, fatigue, and sleepiness. The prevalence of fatigue was higher than other dimensions, with 28% of participants in the third and fourth quartiles. Also, there was no relationship between symptoms and work experience.EUROQUEST questionnaire can be applied in studies of the neurotoxic symptoms. The study of the prevalence of symptoms also indicated that most participants complained about memory and concentration, fatigue, and sleepiness, and these symptoms were observed in all individuals regardless of their work experience.

Dispersing carbon nanomaterials in solvents is effective in transferring their significant mechanical and functional properties to polymers and nanocomposites. However, poor dispersion of carbon nanomaterials impedes exploiting their full potential in nanocomposites. Cellulose nanocrystals (CNCs) are promising for dispersing and stabilizing pristine carbon nanotubes (pCNTs) and graphene nanoplatelets (pGnP) in protic media without functionalization. Here, the underlying mechanisms at the molecular level are investigated between CNC and pCNT/pGnP that stabilize their dispersion in polar solvents. Based on the spectroscopy and microscopy characterization of CNCpCNT/pGnP and density functional theory (DFT) calculations, an additional intermolecular mechanism is proposed between CNC and pCNT/pGnP that forms carbonoxygen covalent bonds between hydroxyl end groups of CNCs and the defected sites of pCNTs/pGnPs preventing re-agglomeration in polar solvents. This work's findings indicate that the CNC-assisted process enables new capabilities in harnessing nanostructures at the molecular level and tailoring the performance of nanocomposites at higher length scales.

Two scalable coating techniques, slot die and spray coating (SC), are used to apply cellulose nanocrystals (CNCs) to the surface of glass fibers with the goal of enhancing interfacial interactions between glass fibers and epoxy and, consequently, the strength of fiber-reinforced composites. The quality of the cellulose coatings and the interfacial shear strength, assessed via the single fiber fragmentation test, are determined as a function of the method and conditions used to coat the fibers. In addition, a comparison with glass fibers coated with identical CNC formulations using a laboratory-scale dip coating (DC) technique is provided. Results from both scalable methods were found to be comparable or superior to the DC technique, with SC outperforming DC by up to 18% on average depending on the coating applied. Further analysis was conducted on coating morphology, fracture behavior, elemental composition, and surface loading. The observed differences can be used to determine which technique is most appropriate for a given application. This work demonstrates the viability in adapting existing, scalable processes for CNC glass fiber coatings and establishes key avenues for future process optimization.

OA Förderung 2022 Arsenic contamination of groundwater occurs due to both geogenic and anthropogenic processes. Conventional arsenic remediation techniques require extraction of groundwater into pump-and-treat systems, which are expensive and require long operational times. Hence, there is a need for cost-effective remediation. In this study, we assessed and validated the in situ remediation of arsenic contamination in groundwater resources using permeable reactive barriers (PRBs) made of injectable, colloidal iron oxide nanoparticles in the laboratory and in field-scale pilot tests. Sand-packed, flow-through column studies were used in order to assess the sorption behavior of the iron oxide nanoparticles using field materials (sand, groundwater) in the laboratory. The breakthrough curves were analyzed using a reactive transport model considering linear and nonlinear adsorption isotherms and were fitted best with a chemical nonequilibrium consideration. The results were used to design a pilot-scale field test. The injected 28 m(3) of nanoparticles (ca. 280 kg dry weight of iron oxide) were successfully delivered to the aquifer via an injection well. No mobile iron was detected downstream, confirming that a stable in situ barrier was formed that did not move with the groundwater flow. Arsenic concentrations in groundwater were reduced to the aimed 50% of the background value, despite the relatively short contact time between arsenic and the iron oxide in the barrier, due to the high flow velocity of 1.21 m/day. We compared the results of the laboratory and field tests and concluded that the single-parameter models based on retardation factor and/or adsorption capacity fail to predict the longevity of the barrier and the evolution of arsenic breakthrough with time, most likely because they do not consider the chemical nonequilibrium effects. Therefore, we propose that upscaling the laboratory findings to field design must be carried out with care and be coupled with detailed reactive transport models.

Background: The average lifespan and the aging population are rising worldwide. So Neurodegenerative Disease (ND) will be one of the most common challenges associated with this population and would be more prevalent in future. The use of Acetylcholinesterase (AChE) inhibitors is one of the most important strategies for memory impairment. Medicinal plants are the most known natural source for accessing the new therapeutic agents. Objective: In this work, we aimed to study in vitro anticholinesterase effect of different concentrations (10, 100, 250, 500, 750 and 1000 μg/ml) of total extract of N. sativa (NTE) and its separated fractions and to study the kinetic of AChE enzyme in the presence of two concentrations of NTE (10 and 100 μg/ml). Methods: Maceration method was used for NTE preparation and different fractions of Petroleum Ether (PTE), Chloroform (CHF) and Methanol (MF). NTE, fractions and the main component of the plant, Thymoquinone (TQ), were assayed for AChE inhibition, using Ellman’s method. Kinetic study of the AChE enzyme was studied in the presence of NTE at 10 and 100 μg/ml using Linweaver- Burk plot too. Results: NTE and all the separated fractions inhibited AChE enzyme in a concentration-dependent manner. The greatest inhibition was shown by CHF and PEF fractions (86.97% and 79.99% at 1000 μg/ml, respectively). With less intensity, NTE, TQ and MF exhibited 76.32%, 68.98 % and 48.39% enzyme inhibition at 1000μg/ml, respectively. The least IC50 value was due to CHF fraction in AChE inhibition (98.28 ± 6.74 μg/ml). Kinetic profile exhibited the mixed mode of AChE inhibition by NTE. This indicates that a particular substance could not be responsible for AChE inhibition, and probably a collection of phytochemicals are involved in this process. Conclusions: N. sativa is a good candidate for seeking the new anticholinesterase agent and could be considered as a good supplement for the health of the elderly.

Background: The safety of the use of medicinal plants is a general challenge among consumers. To improve the use, it is necessary to provide complete profiles of the natural medications for quality control and the therapeutic and toxicity effects. This study was conducted to evaluate the structural and functional toxicity of the methanolic extracts of Salvia rhytidea and Glycine max plants in mice. Methods: After determining the LD50, NMRI mice with mean weight of 25-30 g were treated intraperitoneally with 100, 200 and 400 mg/kg, and orally with 800 mg/kg of the extracts for 7 consecutive days. After the last treatment, the serum samples were prepared and used for the biochemical assays. The liver and left kidney were removed from the animals and fixed in 10% formalin for histopathological examinations. Results: The results indicated that the biochemical parameters of liver and kidneys were not significantly different among the experimental and control groups (P>0.05). Mild degenerative changes in the liver and kidneys were observed at the IP dose of 400 mg/kg and oral dose of 800 mg/kg of both extracts. Conclusion: The use of these plants’ extracts did not induce severe toxicity in the short-term; however, caution should be exercised with the long-term use.

Integrating carbon nanotubes (CNTs) in carbon fiber reinforced polymer (CFRP) composites enhances structural and functional properties; however, it often involves chemical functionalization or proc...

Anisotropic polymer/nanoparticle composites display unique mechanical, thermal, electrical, and optical properties depending on confirmation and configuration control of the composing elements. Processes, such as vapor deposition, ice-templating, nanoparticle self-assembly, additive manufacturing, or layer-by-layer casting, are explored to design and control nanoparticle microstructures with desired anisotropy or isotropy. However, limited attempts are made toward nanoparticle patterning during continuous fiber spinning due to the thin-diameter cross section and 1D features. Thus, this research focuses on a new patterning technique to form ordered nanoparticle assembly in layered composite fibers. As a result, distinct layers can be retained with innovative tool design, unique material combinations, and precise rheology control during fiber spinning. The layer multiplying-enabled nanoparticle patterning is demonstrated in a few material systems, including polyvinyl alcohol (PVA)-boron nitride (BN)/PVA, polyacrylonitrile (PAN)-aluminum (Al)/PAN, and PVA-BN/graphene nanoplatelet (GNP)/PVA systems. This approach demonstrates an unprecedentedly reported fiber manufacturing platform for well-managed layer dimensions and nanoparticle manipulations with directional thermal and electrical properties that can be utilized in broad applications, including structural supports, heat exchangers, electrical conductors, sensors, actuators, and soft robotics. W.X. and R.F. contributed equally to this work. This work was funded by the Global Sports Institute (GSI) at Arizona State University and the U.S. National Science Foundation (NSF, EAGER 1902172). Scopus

Though a revolutionary process, additive manufacturing (AM) has left more to be desired from printed parts, specifically, improved interlayer strength and minimal defects such as porosity. To overcome these common issues, nanocomposites have become one of the most popular materials used in AM, with various nanoparticles used to achieve a variety of characteristics. The use of these technologies together allows for both to synergistically enhance the final printed parts by improving the process and products simultaneously. Here, we introduce a novel, scalable technique to coat ABS pellets with cellulose nanocrystal (CNC) bonded carbon nanotubes (CNT), to improve the adhesion between layers as well as the mechanical properties of printed parts. An aqueous suspension of CNT-CNC is used to coat ABS pellets before they are dried and extruded into filament for printing. The filament produced using this manufacturing method showed an increase in tensile and interlayer strength as well as improved thermal conductivity. This process uses water as solvent and pristine nanoparticles without the need for any functionalization or surfactants, promoting its scalability. This process has the potential to be used with various polymers and nanoparticles, which allows the materials to be specifically tailored to the end application, (i.e. strength, conductivity, antibacterial, etc.). These nanocomposite filaments have the potential to revolutionize the way that additive manufacturing is utilized in a variety of industries.

Nanoparticle spray deposition finds numerous applications in pharmaceutical, electronics, manufacturing, and energy industries and has shown great promises in engineering the functional properties of the coated parts. However, current spray deposition systems either lack the required precision in controlling the morphology of the deposited nanostructures or do not have the capacity for large-scale deposition applications. In this study, we introduce a novel spray system that uses supercritical CO2 to assist the atomization process and create uniform micron-size water droplets that are used as cellulose nanocrystal (CNC) carriers. CNCs are selected in this study as they are abundant, possess superior mechanical properties, and contain hydroxyl groups that facilitate interaction with neighboring materials. We fundamentally investigate the effect of different process parameters, such as injection pressure, gas-to-liquid ratio, the axial distance between the nozzle and substrate, and CNC concentration on the final patterns left on the substrate upon evaporation of water droplets. To this end, we show how tuning process parameters control the size of carrier droplets, dynamics of evaporation, and self-assembly of CNCs, which in turn dictate the final architecture of the deposited nanostructures. We will particularly investigate the morphology of the nanostructures deposited after evaporation of micron-size droplets that has not been fully disclosed to date. Different characterization techniques such as laser diffraction, polarized microscopy, and high-resolution profilometry are employed to visualize and quantify the effect of each process parameter. Numerical simulations are employed to inform the design of experiments. Finally, it is shown that the fabricated nanostructures can be engineered based on the size of the carrier droplets controlled by adjusting spray parameters and the concentration of nanoparticles in the injected mixture. Process parameters can be selected such that nanoparticles form a ring, disk, or dome-shaped structure. Moderate operational conditions, simplicity and time efficiency of the process, and use of abundant and biodegradable materials, i.e., water, CNC, and CO2 promote the scalability and sustainability of this method.

The present article provides a review on the nonlinear mechanical behavior of polymer matrix composites (PMCs). Initially, essential mechanisms driving the nonlinear response of PMCs under differen...

Objectives Almond has been listed in the low FODMAPs (Fermentable Oligo-, Di-, Mono saccharides And Polyols) and is recommended for infant diarrhea and gastrointestinal problem in Iranian folk medicine. In this work, sachet of almond has been designed, formulated and is studied on the clinical symptoms of diarrhea prominent irritable bowel syndrome (IBS-D). Design: almond was standardized on the basis of total protein and carbohydrate content. A sachet of almond and wheat flour (placebo) was formulated and their physicochemical characteristics were investigated. Intervention: In a double blind randomized trial, fifty IBS-D patients were randomly enrolled into the almond and placebo groups, ranked in respect to the severity of symptoms to mild-moderate and severe disease. The patients received almond or placebo sachet (40 g/day,20 days) respectively. Main outcome measure: Patients were assessed for bowel habit, pain severity and frequency and bloating and data was recorded in a data collecting form. Results: The results showed that none of the primary outcomes of the disease is improved in the patients treated with almond. The bowel movement and severity of the pain was significantly increased in the almond treated patients compared to the placebo and baseline (p Conclusion Almond contains high content of oligo-fructan which in high intake might result in a large amount of fermentable carbohydrates that can exacerbate the symptoms of the disease. So, despite the almond inclusion in the low-FODMAPs, the amount of almond intake is a determining factor and here we have controversial results for almond intake in patients with IBS. Mental health and physical activity of patients are also involved in the disease.

This work was aimed to prepare Fe doped TiO2 on an ionic liquid template so that nanoparticles (IL-Fe/TiO2(Ar)) could be formed to degrade acetaminophen (ACE) using the photocatalytic process. The synthesized nanoparticles were characterized using XRD, DRS, FTIR and FESEM–EDX. IL-Fe/TiO2(Ar) enhanced ACE photodegradation using the response surface methodology based on central composite design. The results evidenced that the presence of the 1-octadecyl-3-methylimidazolium bromide template led to development of nanocrystals with a uniform, small grain size. Moreover, the band gap energy calculated for IL-Fe/TiO2(Ar) was observed to be 1.6 eV. The ANOVA results of the photodegradation process revealed a second term model with an adjusted R2 equal to 0.996. The results also showed an ACE removal efficiency of 90.35% under optimal conditions (IL-Fe/TiO2(Ar) dosage = 0.63 g/L, pH 9 and UV irradiation time = 90.35 min). According to the findings, the pseudo first order model was introduced to study photodegradation kinetics. The findings also yielded insight into the most effective variables on degradation of ACE, which were time, IL-Fe/TiO2(Ar) and pH, respectively. Moreover, IL-Fe/TiO2(Ar) had high potential for the removal of ACE by photodegradation and proved to be an appropriate method to obtain optimum operating conditions.

Background & objectives: Leishmaniasis is a major global health problem with no safe and effective therapeutic drugs. This study evaluated the cytotoxic and apoptotic effects of crude extract and fractions of Gossypium hirsutum bulb on Leishmania major stages using advanced experimental models. Methods: Bulbs of G. hirsutum were collected from the Kerman province of Iran. The bulb was extracted using Soxhlet apparatus and different fractions were obtained by column chromatography (CC). Different concentrations of the extract and the fractions were evaluated against L. major and compared with Glucantime®. The cytotoxicity and apoptotic values were analysed by flow cytometry. The fractions obtained in CC were monitored by thin layer chromatography, and fractions with similar chromatographic patterns were mixed. Results: The extract and two fractions, F4 and F5 inhibited the proliferation of L. major promastigotes and amastigotes in a dose-dependent manner at 72 h post-treatment. No significant cytotoxic effects were observed for extract and fractions, as the selectivity index was over 1000, far beyond >10. The mean apoptotic values for L. major were superior to those of Glucantime®. Interpretation & conclusion: Both the crude extract and fractions (F4 and F5) had significant antileishmanial effects on L. major stages, and were were superior relative to Glucantime®. No cytotoxic effects were associated with the extract or fractions and they showed excellent apoptotic index, a possible mechanism behind inducing parasite death. Further investigations are essential to study the effect of G. hirsutum bulb fractions in animal model and clinical settings for planning strategies for the prevention and control of leishmaniasis.

In this study, a modified mesoporous adsorbent (MSU-S) impregnated by aluminum was used to remove the aromatic sulfur compounds from n-decane as the model fuel. Physical and chemical properties of as-synthesized adsorbent were investigated by XRD (X-Ray Diffraction), SEM (Scanning Electron Microscopy), FTIR (Fourier Transform Infrared spectroscopy) and BET (Brunauer–Emmett–Teller) method. Adsorptive desulfurization of model fuel was studied through batch and continues processes under mild temperature and normal atmospheric pressure. The equilibrium adsorption was modeled by Langmuir, Temkin, and Freundlich and the kinetics of adsorption was studied through first, second and intraparticle diffusion models. It was figured out that Temkin and the pseudo-second-order model were best fitting the adsorption equilibrium and describing the kinetics, respectively.