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Introduction: Myocardial protection with cardioplegia is a crucial approach to mitigate myocardial damage during coronary bypass grafting surgery (CABG) with cardiopulmonary bypass (CPB). The major component of the del Nido cardioplegia solution, Plasma-Lyte A, is difficult to obtain in Iran due to high cost. The objective of the current study was to study if the lactated Ringer’s solution as the base for del Nido solution (LR DN) usage is a viable option as a substitute for Plasma-Lyte A in adult patients presenting for CABG surgery. Study design and methods: The present prospective, randomized, blinded study was performed on 18–75-year-old patients ejection fraction (EF) > 35% undergoing CABG with CPB. Patients were randomly allocated to LR DN (modified del Nido cardioplegia) and PL DN (standard del Nido cardioplegia solution) groups. Serum level of cardiac troponin I (cTnI), the type and dosage of inotrope agents, EF, rate of arrhythmia after clamp removal and lactate level were measured and compared between patients of LR DN and PL DN groups. Results: 109 patients were recruited. There were no statistically significant differences between groups for cardiopulmonary bypass times, cardiac enzymes, transfusion requirements, and arterial blood gases. There was no mortality for study patients. Postoperative serum levels of cTnI among patients in the LR DN group was significantly higher than patients of the PL DN group after ICU admission and 24 h post-ICU. Also, more patients needed epinephrine administration in the operating room in the LR DN group (29.8% vs. 11.5%; p: 0.019 vs. PL DN group). Conclusion: We concluded that the standard del Nido cardioplegia solution offers better myocardial protection compared with Ringer’s lactate-based del Nido cardioplegia in adult patients undergoing CABG with CPB. We recommend using standard del Nido cardioplegia with a PL base for patients presenting for CABG surgery.

Better evaluation of existing health programmes, appropriate policy making against emerging health threats, and reducing inequalities in Iran rely on a comprehensive national and subnational breakdown of the burden of diseases, injuries, and risk factors.

The wear resistance and corrosion behavior of titanium and 316L stainless steel were studied after depositing a composite coating of zirconia and hydroxyapatite using the cathodic plasma electrolytic deposition technique. No sign of adhesive wear was observed on coated samples due to the unique surface morphology of the treated samples, after a pin on disk wear test in Ringer’s solution. The average values of friction coefficient for treated titanium and steel samples were observed to be 0.2 which exhibited a decrease of about 4 fold for titanium and 7 fold for steel with respect to the substrates. As a result of potentiostatic cyclic tests in Ringer’s solution the corrosion current density of coated steel (2.47 × 10–10A cm–2) was found to be much lower than for the steel substrate (1.87 × 10–7A cm–2), treated and untreated Ti (6.60 × 10–6, 4.17 × 10–7A cm–2), indicated the increase in corrosion resistance of steel and decrease of it for titanium after coating.

Background: Caesarean section (CS) rates are increasing in both developed and developing countries. Vaginal birth after cesarean (VBAC) is an important option for reducing the CS rate. Objective: The purpose of this study is to explore clinicians' and midwives' views of factors influencing decision-making for VBAC based on the theory of planned behavior. Methods: This qualitative study was carried out in Urmia- Iran, during 2017-2018. Data were collected using in-depth semi-structured interviews with 21 obstetricians and midwives. Participants were selected among governmental hospitals through purposeful sampling until data saturation was reached. Data were analyzed through a directed content analysis approach using the MAXQDA software version 10. Results: Three themes and seven sub-themes including 1. "attitude toward VBAC": positive attitude and negative attitude; 2. "control belief": organizational support, fear, and self-efficacy; and 3. "subjective norms": peer recommendation and maternal perceived pressure were emerged from data analysis. Conclusion: Clinicians' and midwives' positive attitude and clinicians' self-efficacy could reinforce their intentions to select VBAC and support the mother. Insufficient organization support, clinicians' and midwives' negative attitude, clinicians' and women's fear, clinicians' peer recommendation and pressure of outside sources, which is perceived by mothers, could be barrier factors for VBAC.

In this study, Inconel 625 powder was deposited on ASTM A592 steel substrate using laser cladding process. In order to optimize and predict the quality of the obtained coating, empirical-statistical method was used and the linear relationship between the coating geometries for each sample (angle, width, height, depth of penetration and dilution) and cladding parameters (power, powder feeding rate, and scanning rate) was obtained by the use of regression method. Using these relationships, a process map has been extracted to obtain the best quality for the cladding process. Hence, it is possible to obtain the optimal parameters of coating geometry and the main laser parameters for the deposition of Inconel 625 powder on the ASTM A592 steel substrate with minimum porosity and without crack.

ABSTRACTHydrate formation and water accumulation during transmission process can be prevented by effective dehydration of gas streams. This study investigates the application of multi-layer perceptron artificial neural network to estimate natural gas dew point temperature using contactor temperature and TEG purity as independent variables. A dataset comprised of 173 data points is extracted from the literature. The proposed model is considered a great help for engineers to have precise dew point temperature predictive tool in wide ranges of concerning variables. Results obtained from the proposed model show R-squared and mean square error of 1.000 and 0.156, respectively. Accordingly, the remarkable agreement between predicted and experimental values is observed.

Cancer-induced immune responses affect tumour progression and therapeutic response. In multiple murine models and clinical datasets, we identified large variations of neutrophils and macrophages that define ‘immune subtypes’ of triple-negative breast cancer (TNBC), including neutrophil-enriched (NES) and macrophage-enriched subtypes (MES). Different tumour-intrinsic pathways and mutual regulation between macrophages (or monocytes) and neutrophils contribute to the development of a dichotomous myeloid compartment. MES contains predominantly macrophages that are CCR2-dependent and exhibit variable responses to immune checkpoint blockade (ICB). NES exhibits systemic and local accumulation of immunosuppressive neutrophils (or granulocytic myeloid-derived suppressor cells), is resistant to ICB, and contains a minority of macrophages that seem to be unaffected by CCR2 knockout. A MES-to-NES conversion mediated acquired ICB resistance of initially sensitive MES models. Our results demonstrate diverse myeloid cell frequencies, functionality and potential roles in immunotherapies, and highlight the need to better understand the inter-patient heterogeneity of the myeloid compartment. Kim et al. demonstrate neutrophil- and macrophage-enriched subtypes in triple-negative breast cancer and how these immune profiles affect therapeutic responses to immune checkpoint blockade.

ABSTRACTThis paper presents an intelligent method based on Improved Particle Swarm Optimisation to solve a unit commitment problem that takes into account the uncertainty in the demand. This uncertainty is included in the optimisation problem as a joint chance constraint that bounds the minimum value of the probability to jointly meet the deterministic power balance constraints. The demand is modelled as a multivariate, normally distributed, random variable and the correlation among different time periods is also considered. To demonstrate the effectiveness and robustness of the proposed algorithm, a system with 10 thermal and wind units with various conditions is simulated. The results and numerical experiments are compared with other methods to provide valuable information for both operational and planning problems.

Aim and Objective: The aim of this paper is to introduce HSBM as a green and environmentally friendly technique for the synthesis of thiochromeno[4,3-b]pyran and benzo[h]thiazolo[2,3-b]quinazoline derivatives over ZnAl2O4 nanopowders as an efficient catalyst. Materials and Methods: ZnAl2O4 nanopowders were synthesized via a co-precipitation of Zn(NO3)2 and Al(NO3)3 salts and were characterized by XRD, FE-SEM, TEM and DLS techniques. The as-prepared ZnAl2O4 nano-powders have been used as a catalyst on the synthesis of pyran nucleus using high-speed ball milling (HSBM) technique. The structure of products was confirmed with NMR analysis. Results: ZnAl2O4 exhibits a cubic crystal structure (Space group: Fd-3m) with the average crystallite size of 41 nm. The average particle size of ZnAl2O4 nano-powders determined by DLS technique is 55 nm. The catalytic activity of nano-powders was examined on the synthesis of 2- amino-4,5-dihydro-4-arylthiochromeno[4,3-b]pyran-3-carbonitriles, (8Z)-2-amino-8-arylidene-4,5, 7,8-tetrahydro-4-arylthiopyrano[4,3-b]pyran-3-carbonitriles, 4-aryl-3,4,5,6-tetrahydrobenzo[h]quinazoline- 2(1H)-thiones and 4-aryl-1,3,4,5-tetrahydro-2H-thiochromeno[4,3-d]pyrimidine-2-thione derivatives. All products were obtained in high yields with short reaction times. Conclusion: ZnAl2O4 nanopowders were prepared via a cost-effective co-precipitation method and showed good potential for the synthesis of 4H-pyran analogous in good yields. The salient advantages of HSBM technique include environmentally friendly with reduced solvents, is a simple technique and has low energy costs.

The effective elastic-piezoelectric properties of nanostructures have been shown to be strongly size-dependent. In this paper, a nonlocal second-order shear deformation formulation is presented to study the size-dependent thermal buckling of embedded sandwich piezoelectric nanoplates with functionally graded core. Temperature is considered as uniform and nonlinear distributions across plate’s thickness direction. Based on the developed nonlocal second-order shear deformation theory, the size-dependent equations of motion are derived. The nonlocal thermal buckling responses of simply supported nanoplates are solved via Navier method. The reliability of present approach is verified by comparing the existing results provided in the open literature. The influences of nonlocal parameter, gradient index, electric voltage, and Winkler–Pasternak parameters on the thermal buckling characteristics of functionally graded nanoplates are examined.

In the current study, a set of urea–formaldehyde microcapsules (UFMs) were synthesized at different conditions via the in situ polymerization method. Encapsulation ability of the UFMs was studied by altering the synthesis parameters, such as formaldehyde to urea molar ratio (0.94, 1.88, 2.81), time (1, 4, 7h), temperature (25, 55, 85°C) and pH (3, 7, 11). The capsules were characterized by optical and electron microscopy (OM, SEM and TEM), particle size analysis (PSA), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric/differential thermal analysis (TG/DTA). According to the results, for successful formation of UFMs, the pH value of the synthesis solution must be below 7 and the F/U molar ratio value must exceed 0.94. Effects of temperature and the pH value of the prepared solution were interdependent. To conclude, the results led to determination of the optimum UFM synthesis condition which presented the most effective formation of UFMs. The higher F/U molar ratio as well as higher curing temperatures in UFM-9, increased the UFMs degradation temperature. In order to further investigate the results, the synthesis of the optimized UFM (UFM-Opt.) was conducted, presenting the most effective development of UFMs.

To provide photocatalytic textiles, application of TiO2nanoparticles by surface modifications during the manufacturing process is known as a reliable choice. In this study, nitrogen-doped TiO2nanoparticles were synthesized by sol–gel route at two different water/triethylamine ratios and applied to the textiles which provides photocatalytic properties that unlike the conventional photocatalytic textiles, does not necessarily need UV radiations of high energy photons. N-doped TiO2nanoparticles were coated over textiles during the synthesizing process. Microstructure and morphology of synthesized N-doped TiO2nanoparticles were evaluated by XRD, PSA and SEM/EDS analysis. The results of XRD analysis indicated that the amorphous phase transformed slightly into an anatase crystallite without calcination at high temperature. The morphology confirmed that doping process had significant effect on the appearance of the synthesized nanoparticles and implied the effect of the presence of the N-doped source material on the morphology. The PSA analysis showed narrow distribution of about 15nm for diameter of synthesized N-doped TiO2nanoparticles. According to UV–vis spectra, the band gap energy was measured 2.98eV which exhibits high absorption in visible light range due to its low band gap energy. The results show that adding nitrogen increases the absorption wavelength of the N-doped TiO2nanoparticles and N-doped TiO2coated textiles shows super hydrophilic behavior examined by DSA analysis. The photodegradation of methylene blue (MB) over textiles was investigated under UV-radiation, visible light and dark conditions. Super-hydrophilicity and methylene blue photodegradation properties with the most homogenous nanoparticle distribution over textiles were achieved without utilization of UV radiation.

Despite the potential for more realistic results, the behavior of anisotropic structures has not been comprehensively studied. Consequently, a numerical investigation is conducted to examine both static and dynamic deflections in nano-sized plates composed of triclinic materials, which necessitate a more complex formulation involving 21 independent elastic components. To model the triclinic plate, a higher order shear deformable theory is employed, which includes 7 unknowns and is combined with Eringen nonlocal model in differential form. The differential quadrature method is then utilized as a numerical tool to solve the problem, accounting for various edge boundary conditions. Subsequently, numerical examples are provided to demonstrate the behavior of static and time-dependent transversal deflections, as well as normal and shear stresses, in rectangular triclinic plates, considering nonlocality, geometrical parameters, and boundary conditions. Moreover, a unique comparison is presented to highlight the significance of anisotropy when compared to isotropic approximations. The data reported herein not only represents a mechanical investigation but also serves as a valuable reference for future research on triclinic materials.

A novel proton-exchange polymer composite membrane was synthesized using Nafion®, tetraethoxysilane-modified carbon nanotubes (CNTs) and phosphotungstic acid-modified carbon nanotubes with the aim of using direct methanol fuel cells (DMFCs). Physicochemical properties of the modified CNTs and fabricated composite membranes were investigated by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, water uptake, thermogravimetric analysis, ion exchange capacity, proton conductivity and methanol permeability tests. It was demonstrated that chemical surface modification of CNTs and introduction of the phosphotungstic acid (PWA) groups effectively improved the performance of DMFC. It was found that the presence of PWA groups on the surface of CNTs led to the formation of strong electrostatic interactions between the PWA groups and clusters of sulfonic acid in Nafion®macromolecules. Hence, the incorporation of inorganic phosphotungstic super-acid-doped silicon oxide-covered carbon nanotubes (CNT@SiO2-PWA) into Nafion®matrices enhanced the proton conductivity of the prepared membranes. Moreover, the methanol permeability was reduced to 2.63 × 10−7cm2s−1in comparison with the recast Nafion®membrane (2.25 × 10−6cm2s−1). Enhancing the proton conductivity and reducing the methanol permeability, the selectivity of the prepared nanocomposite membranes was enhanced to a greater value of 330,700 S s cm−3as compared to the value of 38,222 S s cm−3for recast Nafion®.

In this paper, the size-dependent effects on the time-dependent bending and shearing responses of single-layer graphene sheets (SLGSs) induced by displacement of the concentrated moving load along the SLGSs are studied. Hence, the equations of motion are derived by applying two-variable refined plate theory in conjunction with the nonlocal elasticity theory via Hamilton’s principle. The two independent unknowns denoting the dynamic behaviour of plates are defined by the developing state-space method for this case, and Navier-solution method is employed to obtain the bending and shearing deflections due to the variation of velocity and time. The primary results for free and forced vibrations of nanoplates are approved by existing literature to illustrate the correctness of the present formulation and solution methods. Next, a solution including both the bending and shearing dynamic deflections of SLGSs under the moving load is derived for the first time in this research. Moreover, the roles of different parameters such as load velocity, length-to-thickness ratio, and small-scale effects on the dynamic deflections of SLGSs are addressed and discussed.

In this study, the size-controlled synthesis of silver nanoparticles (Ag NPs) via chemical reduction method by NaBH4as a reducing agent and poly(vinyl pyrrolidone) or PVP as a stabilizing agent is reported. Changing of ratios between reducing agent and stabilizing agent relative to AgNO3-optimized conditions for synthesis of stable Ag NPs was studied. The formation of Ag NPs was tracked by UV–Vis spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. Particle size distribution was studied by particle size analyzer, and the morphology was examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The optical properties of the synthesized Ag NPs were also investigated. The optimized Ag NPs were very stable even after 1 month that was due to effective stabilization by PVP molecules. The mechanism of Ag NPs formation and stabilization is discussed in detail.

AbstractIn this study, to design an efficient control system for a Reverse osmosis (RO) desalination plant, a model predictive control (MPC) was established and compared to the obtained control system based on proportional–integral–derivative (PID) controllers. In order to control two controlled variables, namely permeate flow rate and conductivity, two PID controllers’ parameters were tuned based on the internal model control (IMC) rule and an MPC controller was established using the dynamic matrix control algorithm. The control performance assessment of both PID and MPC controllers were carried out using prediction error approach and their control performances were compared to that of the PID controllers which tuned by Ziegler–Nichols rule from the literature. The results showed that among the designed controllers, the PID controllers tuned by IMC method are more capable than other controllers to control the considered RO desalination plant.

In this study, to design an efficient control system for a Reverse osmosis (RO) desalination plant, a model predictive control (MPC) was established and compared to the obtained control system based on proportional–integral–derivative (PID) controllers. In order to control two controlled variables, namely permeate flow rate and conductivity, two PID controllers’ parameters were tuned based on the internal model control (IMC) rule and an MPC controller was established using the dynamic matrix control algorithm. The control performance assessment of both PID and MPC controllers were carried out using prediction error approach and their control performances were compared to that of the PID controllers which tuned by Ziegler–Nichols rule from the literature. The results showed that among the designed controllers, the PID controllers tuned by IMC method are more capable than other controllers to control the considered RO desalination plant.

In this study, mechanical and dielectric properties of epoxy nanocomposites with two types of graphene, < 10 layer stacks (GEC10) and < 30 layer stacks (GEC30) were investigated. Results showed that the number of graphene layers remarkably affected the dielectric properties of epoxy nanocomposites. The real and imaginary parts of relative permittivity and loss tangent of GEC10 samples were noticeably enhanced and reached to 1.29, 20 and 15.6 times respectively for 1 wt-% graphene sample compared to GEC30 samples. Meanwhile, tensile tests showed a peak for tensile strength of GEC10 and GEC30 samples with 0.1 wt-% graphene, which improved by 13 and 7.9% with respect to pure epoxy respectively. In addition, flexural properties did not change significantly compared to the pure epoxy.

In this study, mechanical and dielectric properties of epoxy nanocomposites with two types of graphene,

Background: Many researchers have tried to enhance materials functions in different aspects of science using nano-modification method, and in many cases the results have been encouraging. To evaluate the histopathological responses of the micro-/nano-size cement-type biomaterials derived from calcium silicate-based composition with addition of nano tricalcium aluminate (3CaO.Al2O3) on bone healing response. Material and Methods: Ninety mature male rabbits were anesthetized and a bone defect was created in the right mandible. The rabbits were divided into three groups, which were in turn subdivided into five subgroups with six animals each based on the defect filled by: white mineral trioxide aggregate (WMTA), Nano-WMTA, WMTA without 3CaO.Al2O3, Nano-WMTA with 2% Nano-3CaO.Al2O3, and empty as control. Twenty, forty and sixty days postoperatively the animals were sacrificed and the right mandibles were removed for histopathological evaluations. Kruskal-Wallis test with post-hoc comparisons based on the LSMeans procedure was used for data analysis. Results: All the experimental materials provoked a moderate to severe inflammatory reaction, which significantly differed from the control group (p< 0.05). Statistical analysis of bone formation and bone regeneration data showed significant differences between groups at 40- and 60- day intervals in all groups. Absence of 3CaO.Al2O3 leads to more inflammation and foreign body reaction than other groups in all time intervals. Conclusions: Both powder nano-modification and addition of 2% Nano-3CaO.Al2O3 to calcium silicate-based cement enhanced the favorable tissue response and osteogenesis properties of WMTA based materials. [ABSTRACT FROM AUTHOR]

An understanding of the mechanisms determining MYC’s transcriptional and proliferation-promoting activities in vivo could facilitate approaches for MYC targeting. However, post-translational mechanisms that control MYC function in vivo are poorly understood. Here, we demonstrate that MYC phosphorylation at serine 62 enhances MYC accumulation on Lamin A/C-associated nuclear structures and that the protein phosphatase 2A (PP2A) inhibitor protein CIP2A is required for this process. CIP2A is also critical for serum-induced MYC phosphorylation and for MYC-elicited proliferation induction in vitro. Complementary transgenic approaches and an intestinal regeneration model further demonstrated the in vivo importance of CIP2A and serine 62 phosphorylation for MYC activity upon DNA damage. However, targeting of CIP2A did not influence the normal function of intestinal crypt cells. These data underline the importance of nuclear organization in the regulation of MYC phosphorylation, leading to an in vivo demonstration of a strategy for inhibiting MYC activity without detrimental physiological effects.

Because of extraordinary physical, chemical and mechanical properties, graphene nanosheets (GNS) are suitable fillers for optimizing the properties of different polymers. In this research, the effect of GNS content (up to 1 wt.%) on tensile and flexural properties, morphology of fracture surface, and toughening mechanism of epoxy were investigated. Results of mechanical tests showed a peak for tensile and flexural strength of samples with 0.1 wt.% GNS such that the tensile and flexural strength improved by 13% and 3.3%, respectively. The Young’s modulus and flexural modulus increased linearly with GNS content, although the behavior of the Young’s modulus was more remarkable. Morphological investigations confirmed this behavior because the GNS dispersion in the epoxy matrix was uniform at lower contents and agglomerated at higher contents. Finally, microscopical observation showed that the major toughening mechanism of graphene-epoxy nanocomposites was crack path deflection, which changed the mirror fracture surface of the pure epoxy to rough surface.

In this paper, the free vibration of simply supported rectangular nanoplates based on two-variable refined plate theory using strain gradient elasticity theory is presented. Various formats of gradient elasticity theory are available in the literature. In this work, strain gradient elasticity theory with two gradient constants is used. An analytical method is adopted to find the natural frequencies of rectangular nanoplates. Present results are compared with the results of other works done previously. It is mentioned that it is the first time that two-variable refined theory and strain gradient elasticity theory with two gradient constants are used together for free vibration of nanostructures, so the results of the present work can be used as bench mark for future works.

The propagation of bulk waves in rectangular nanoplates is studied on the basis of nonlocal three-dimensional elasticity theory. The nonlocal theory applies to both thin and thick rectangular orthotropic nanoplates. The dispersion relation for the waves is derived analytically. Our results are checked against data for macroplates. The influence of nonlocality and other parameters on the wave frequency and phase velocity is discussed.

In this work, powder metallurgy was performed for preparation of iron-based soft magnetic composites (SMCs). For this purpose, iron powders were coated with a thin alumina insulating layer using the sol–gel process, and then compacted for characterization. Microstructural analysis confirmed the formation of an alumina insulating layer with high thermal stability and uniform coverage on the powder surfaces. The alumina coating increased the magnetic permeability of the composites at high frequencies as a result of increased electrical resistivity and decreased eddy current loss. In addition, the different components of the total loss factor were calculated by means of a loss separation method. It was found that by addition of 8 wt.% insulation, the hysteresis loss coefficient increased from 2.7 × 10-3to 4 × 10-3while the eddy current loss coefficient decreased from 3.00 × 10-6to 1.53 × 10-6as compared with pure iron compacts.

The mechanical decomposing and mechanochemical reductions of silver oxide for preparation of nanocrystalline silver powders by high planetary ball mill was investigated. XRD and HRSEM techniques were used to characterize the structural evolution and morphological changes of products. The results show that the nanostructured silver with an average crystallite size of 14 nm and internal strain of 0.75% is synthesized by mechanical decomposing of Ag2O after 95 h milling. While, the product of mechanochemical reduction of silver oxide using graphite after 22 h milling is nanostructured silver with an average crystallite size of 28 nm and internal strain of 0.44%.

This study proposes a systematic approach to analyzing and optimizing combined gas turbine (GT) and reverse osmosis (RO) systems. Two systems combining RO to produce freshwater and a GT power plant to generate the required power for the RO system were modeled. In the first system, the coupling between the RO and the power plant was only mechanical; while in the second system, the coupling was both mechanical and thermal, using a refrigeration cycle. The effects of seawater temperature and intake air temperature on the freshwater production of the systems were investigated and their optimal values were calculated. Economic modeling was applied in order to calculate the unit product cost of freshwater. The second system, with two RO units under optimal operation conditions, can increase freshwater production by 26% and save 21% in the production cost of 1 m3of freshwater as compared to the first system as a base system.

AbstractThis study proposes a systematic approach to analyzing and optimizing combined gas turbine (GT) and reverse osmosis (RO) systems. Two systems combining RO to produce freshwater and a GT power plant to generate the required power for the RO system were modeled. In the first system, the coupling between the RO and the power plant was only mechanical; while in the second system, the coupling was both mechanical and thermal, using a refrigeration cycle. The effects of seawater temperature and intake air temperature on the freshwater production of the systems were investigated and their optimal values were calculated. Economic modeling was applied in order to calculate the unit product cost of freshwater. The second system, with two RO units under optimal operation conditions, can increase freshwater production by 26% and save 21% in the production cost of 1 m3of freshwater as compared to the first system as a base system.

Sliding wear behavior of severely deformed 6061 aluminum alloy sheets by accumulative roll bonding (ARB) process subjected to dry sliding wear at different loading and sliding velocities was investigated using a pin on disc wear machine. The sheets were processed up to five ARB cycles in order to induce a high strain (~ 4.0) to the samples. EBSD results showed that after five cycles of ARB, sheets were found to contain ultra-fine grains with high fraction of high angle grain boundaries. Wear was continuously monitored by measuring the weight losses and morphologies of worn surfaces by scanning electron microscope (SEM), and a model for the wear of the ARB-processed samples was proposed.

A micro-computer program was developed to plot deformation mechanism maps for metals and substitutional solid solutions such as Ti-6 wt% Al. The package written in Turbo Basic is versatile and can be run to print out maps, using the related stored data files. In modelling the maps, the rate equations governing different deformation mechanisms were employed to find the dominant mechanisms and strain rate contours. In particular, the map for Ti-6 wt% Al was generated and it was found that the power law creep dominated over a wider range of stresses and temperatures than that of pure titanium. It is concluded that the strengthening effect of aluminium has shifted the iso-strain rate contours to higher stresses and temperatures.

The aim of present paper is to improve the efficiency and increase the accuracy of models for carbon nanotubes (CNTs) reinforced nanocomposites by eliminating three theoretical assumptions: 1- The CNT's structure is pristine and has no defect, 2- The CNTs as reinforcements have uniformly distributed pattern in the nanocomposites, 3- The lack of curvature in the structure of CNTs as reinforcements. Experimental observations show different types of defects such as vacancy and stone–wales defects in produced CNTs. Therefore, the assumption of pristine CNTs is not accurate. On the other hand, it can be seen by different types of microscopes that CNTs have some aggregations in specific points in the nanocomposites when the synthesis process of nanocomposites is over. Images taken by microscopes also show that the CNTs reinforced nanocomposites do not have straight structure and they have curvatures. In this paper, first, it is decided to concentrate on CNTs despite their defects, and after that, it is focused on the agglomerations of CNTs, and in the last step, the waviness of CNTs is included in present model. For this purpose, a higher order integral plate theory is derived with considering the defected/aggregated/wavy CNTs and after that, vibration and wave propagation of nanocomposites are studied. It is noted that the size effect is also included here by adopting Eringen's nonlocal elasticity theory. To show the accuracy of present model, the results are calibrated with experimental results and are compared with theoretical models. After verifying present model, three main goals of this paper are examined. The first goal is comparing the results of nanocomposites for uniformly distributed and aggregated CNTs, and the second goal is making comparison between the results of nanocomposites for pristine and defected CNTs, and at the end, the behaviors of nanocomposites for wavy and straight CNTs are compared.

Elastic bulk wave characteristics of doubly curved nanoshell made of functionally graded (FG) anisotropic material are studied. The effective properties of FG anisotropic material vary along the thickness direction. A higher-order shear deformation shell theory and the Bi-Helmholtz nonlocal strain gradient theory are, respectively, utilized to model the nanoshell as a continuum model and predicting the size-dependent behavior. The Hamiltonian principle is adopted to obtain the governing equations of wave motion. These equations are solved analytically to evaluate the wave characteristics of the nanoshell. Emphasizing the effect of parametric excitation, the influences of small-scale parameters, exponential factor, magnetic field intensity, initial stress, elastic foundation parameters, and wave number are assessed on the wave dispersion response of FG anisotropic nanoshell.