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India has witnessed a substantial growth in the production of plastics and an increased consumption of plastic. In the absence of adequate waste collection and segregation process, the management of the waste created by discarded used plastics items, especially ones used for packaging applications has become a challenging task. This article provides an overview of the resource recovery from plastic waste with consideration of integrated waste management (IWM), to evaluate the best possible option for tackling waste in Indian circumstances.

The measurement of patients’ dosages of radiation caused by medical diagnostics continues to be challenging. A Cantor sequence photonic crystal structure using porous silicon doped with a polymer of polyvinyl alcohol, carbol fuchsin and crystal violet (DPV) is proposed. The influence rules of geometrical and optical parameters such as the radiation doses, number of periods, porosity of porous layers, incident angle and thickness of layers are investigated using MATLAB based on the transfer matrix method. The transmittance of the Cantor sequence of a defective photonic crystal sensor under different conditions is investigated to select the optimum conditions. The proposed system recorded the accepted sensitivity of 0.265nm/Gy, FoM of 6.5Gy${}^{-1}$, Q of 12,701, RS of $6\times 10^{-3}$ and LoD of $8\times 10^{-3}$ for gamma radiation. The suggested detector has simple design, accurate monitoring efficiency and immense potential for gamma radiation sensing.

Mesoscale simulation techniques have helped to bridge the length scales and time scales needed to predict the microstructures of cured epoxies, but gaps in computational cost and experimental relevance have limited their impact. In this work, we develop an open-source plugin epoxpy for HOOMD-Blue that enables epoxy crosslinking simulations of millions of particles to be routinely performed on a single modern graphics card. We demonstrate the first implementation of custom temperature-time curing profiles with dissipative particle dynamics and show that reaction kinetics depend sensitively on the stochastic bonding rates. We provide guidelines for modeling first-order reaction dynamics in a classic epoxy/hardener/toughener system and show structural sensitivity to the temperature-time profile during cure. We conclude with a discussion of how these efficient large-scale simulations can be used to evaluate ensembles of epoxy processing protocols to quantify the sensitivity of microstructure on processing.

The effects of different percentages of multiwall carbon nanotube (MWCNT) on natural frequencies of polymer composite plates of varying edge-to-thickness ratio, aspect ratio and boundary conditions at ambient temperature are investigated experimentally and numerically. Conventional hand lay-up technique is used to prepare the MWCNT polymer composite plates with different percentages of carbon nanotubes (CNTs) mixed to the polymer. The elastic properties are determined experimentally by conducting uniaxial tensile test in the universal testing machine INSTRON 8862 as per ASTM D-3039. A set of experiments were conducted for the natural frequencies of vibration of MWCNT composite plates using the Bruel and Kjaer Fast Fourier Transform (FFT) analyzer with pulse platform. Detailed parametric studies are carried out to determine the effect of weight fraction of CNTs, aspect ratios, edge-to-thickness ratios and boundary conditions on the natural frequency of composite plates. Numerical solutions were obtained by the commercial finite element method (FEM) package ABAQUS. A simulation model is developed using the same geometrical and material properties determined experimentally from which the frequency responses are obtained. The simulation results are found to be consistent with the experimental ones. The results obtained showed an increase in elastic properties and natural frequencies up to 0.3 wt.% of MWCNT and decrease thereafter for all cases due to agglomeration of CNT in the polymer matrix. The morphology and dispersion of the CNTs in composites at micro level are investigated by using scanning electron microscopy (SEM) to further corroborate the behavior of specimens.

Membrane technologies are essential for water treatment, bioprocessing and chemical manufacturing. Stimuli-responsive membranes respond to changes in feed conditions (e.g., temperature, pH) or external stimuli (e.g., magnetic field, light) with a change in performance parameters (permeability, selectivity). This enables new functionalities such as tunable performance, self-cleaning and smart-valve behavior. Polymer self-assembly is a crucial tool for manufacturing such membranes using scalable methods, enabling easier commercialization. This review surveys approaches to impart stimuli responsive behavior to membrane filters using polymer self-assembly.

The glass transition temperature (T_g) values of three classes of vinyl polymers, i.e. polystyrenes, polyacrylates, and polymethacrylates, were predicted by using a quantitative structure–property relationship (QSPR) model constructed by back-propagation (BP) neural network. The four descriptors (the rigidness descriptor R_HR resulted by hydrogen-bonding moieties group and/or rings, the chain mobility n, the molecular average polarizability α, the net charge of the most negative atom q^-) were obtained directly from the polymers' monomer structures. Stepwise multiple linear regression analysis (MLRA) and artificial neural network (ANN) were used to generate the model. Simulated with the final optimum BP neural network [4–2–1], the results showed that the predicted T_g values were in good agreement with the experimental data, with a training set root-mean-square (rms) error of 20.478 K (R = 0.955) and a prediction set rms error of 20.174 K (R = 0.955).

Carbon nanomaterial (CNM)-reinforced polymer composite is broadly employed in emergent industrial needs due to advanced mechanical properties. In this research paper, a comparatively innovative integrated approach (SOA–CoCoSo) is proposed by using Principal Component Analysis (PCA)-based Combined Compromise Solution (CoCoSo) and Seagull Optimization Algorithm (SOA). This modified module is used in the drilling operation of zero-dimensional (0D) carbon nano-onion (CNO)-reinforced polymer (epoxy) composite. The desired machining performances, namely, surface roughness ($R_a$), thrust force (Th), and Torque (Tr), are optimized to improve the quality and productivity concerns. The control of process constraints, i.e. the wt.% of nanomaterial ($A$), spindle speed ($B$), and feed rate ($C$), was performed to achieve the desired objective value. The drilling experimentation was executed at three different levels of Box–Behnken Design (BBD). The objective function of PCA–CoCoSo was fed as input into the SOA. To acquire a better work efficiency, higher spindle speed, lower feed rate, and incremental wt.% of nanomaterial reinforcement are considered. The results demonstrated that the wt.% of CNO reinforcement and feed rate are the most influential factors for optimal machining performance results. The optimal constraints condition from the SOA–CoCoSo hybrid module is found at a combination of lower level of CNO wt.% (0.5wt.%) and feed rate (61mm/min) and high value of spindle speed (1500rpm). Also, the hybrid SOA–CoCoSo module shows a lesser amount of error percentage than the usual PCA–CoCoSo. The experiments were performed to confirm the feasibility of the suggested hybrid module for optimizing the varying machining parameters. The results indicated that the hybrid method is more efficient than the conventional method.

A novel and shape-controlled synthesis method for uniformly-shaped poly(p-phenylenediamine) (PpPD) microparticles was developed using (NH₄)₂S₂O₈ (APS) as an oxidant. The results demonstrated that the morphologies of PpPD varied from nanofibers to nanospheres and nest-like microspheres by tuning the pH of solution. Tiny pH change leads to the significant change in product morphology. The structure of microspheres is similar to graphene which was first discovered. Further study showed that the PpPD nanofibers were dimer. The difference in the structure of PpPD nanofibers and nanospheres (microspheres) resulted in different solubility in water. The nanosized oligomer crystallites served as starting templates for the nucleation of PpPD nanofibers. Further growth of nanofibers was proceeded by the self-organization of phenazine units or their blocks located at the ends of the PpPD chains.

Sensing is a basic ability of smart structures. Self-sensing involves the structural material sensing itself. No device incorporation is needed, thus resulting in cost reduction, durability enhancement, sensing volume increase and absence of mechanical property diminution. Carbon fiber renders electrical conductivity to a composite material. The effect of strain/damage on the electrical conductivity enables self-sensing. This review addresses self-sensing in structural composite materials that contain carbon fiber reinforcement. The composites include polymer-matrix composites with continuous carbon fiber reinforcement (relevant to aircraft and other lightweight structures) and cement–matrix composites with short carbon fiber reinforcement (relevant to the civil infrastructure). The sensing mechanisms differ for these two types of composite materials, due to the difference in structures, which affects the electrical and electromechanical behaviors. For the polymer–matrix composites with continuous carbon fiber reinforcement, the longitudinal resistivity in the fiber direction decreases upon uniaxial tension, due to the fiber residual compressive stress reduction, while the through-thickness resistivity increases, due to the fiber waviness reduction; upon flexure, the tension surface resistance increases, because of the reduction in the current penetration from the surface, while the compression surface resistance decreases. These strain effects are reversible. The through-thickness resistance, oblique resistance and interlaminar interfacial resistivity increase irreversibly upon fiber fracture, delamination or subtle irreversible change in the microstructure. For the cement–matrix composites with short carbon fiber reinforcement, the resistivity increases upon tension, due to the fiber–matrix interface weakening, and decreases upon compression; upon flexure, the tension surface resistance increases, while the compression surface resistance decreases. Strain and damage cause reversible and irreversible resistance changes, respectively. The incorporation of carbon nanofiber or nanotube to these composites adds to the costs, while the sensing performance is improved marginally, if any. The self-sensing involves resistance or capacitance measurement. Strain and damage cause reversible and irreversible capacitance changes, respectively. The fringing electric field that bows out of the coplanar electrodes serves as a probe, with the capacitance decreased when the fringing field encounters an imperfection. For the cement-based materials, a conductive admixture is not required for capacitance-based self-sensing.

This chapter gives a brief description of the definition, development history and classification of cosmetics, and introduces the advantages and beautiful prospects of adaptive and functional polymers in the cosmetics field. We also further discuss the properties and cosmetic applications of five types of typical adaptive and functional polymers in this chapter, which are: hydrogels, cyclodextrins, polysaccharides, shape memory polymers and nanopolymer particles.

The monomeric and polymeric tetra-aminophthalocyane to, cobalt(II) species adsorbed onto graphite electrodes are active in electrocatalytic oxygen reduction. While the monomeric species is unstable, the polymerized species is an effective and stable reduction catalyst over a wide pH range. Both the two-electron reduction of oxygen to hydrogen peroxide and the four-electron reduction of oxygen to water are characterized by cyclic voltammetry, rotating disc and rotating ring-disc studies with appropriate theoretical analysis. Some mechanistic information is obtained. This is the first cobalt phthalocyanine species to provide a four-electron reduction pathway which exists over a wide pH range and is stable. The stability is associated with the polymerization since the monomeric species is not stable.

In this study, we describe the synthesis, characterization and evaluation of colloidal dispersion gels (CDGs) to be used as in-situ fluid diversion. The chemical stability of CDGs was improved by modifying the polymer mixture. The CDGs were synthesized by free radical crosslinking polymerization using 2-acrylamido-2-methylpropane sulfonic acid (AMPS), Acrylic acid (AAc), partially hydrolyzed polyacrylamide (HPAM) and chromium triacetate crosslinker. The effect of crosslinker/polymer concentration, salinity, gelation time, rheological behavior, particle size distribution of CDGs, also their thermo-chemical stabilities and resistance/residual resistance factor (RRF) were investigated.

Devices such as solar and fuel cells have been studied for many decades and noticeable improvements have been achieved. This paper proposes a Micro Photosynthetic Power Cell (μPSC) as an alternative energy-harvesting device based on photosynthesis of blue-green algae. The effect of important biodesign parameters on the performance of the device, such as no-load performance and voltage–current (V–I) characteristics, were studied. Open-circuit voltage as high as 993 mV was measured while a peak power of 175.37 μW was obtained under an external load of 850 Ω. The proposed μPSC device could produce a power density of 36.23 μW/cm², voltage density of 80 mV/cm² and current density of 93.38 μA/cm² under test conditions.

Immunotherapy has offered an alternative therapy method for cancer patients with metastatic tumors or who are not suitable for surgical resection. Different from traditional surgery, radiotherapy and chemotherapy, immunotherapy mainly restores the activity of the body’s own immune cells silenced in the tumor microenvironment to achieve anticancer therapy. Gene therapy which corrects abnormal expression of immune cells in tumor microenvironment by delivering exogenous genes to specific immune cells, is the most widely studied immunotherapy. Although most available gene delivery vectors are still viral vectors, the further application of viral vectors is still limited by the immunogenicity and mutagenesis. Based on this, cationic polymeric gene vectors with high flexibility, high feasibility, low cost and high safety have been widely used in gene delivery. The structural variability of polymers allows specific chemical modifications to be incorporated into polymer scaffolds to improve their physicochemical properties for more stable loading of genes or more targeted delivery to specific cells. In this review, we have summarized the structural characteristics and application potential in cancer immunotherapy of these polymeric gene vectors based on poly(L-lysine), poly(lactic-co-glycolic acid), polyethyleneimine, poly(amidoamine) and hydrogel system.

Nowadays tools based on Scanning Probe Methods (SPM) have become indispensable in a wide range of applications such as cell imaging and spectroscopy, profilometry, or surface patterning on a nanometric scale. Common to all SPM techniques is a typically slow working speed which is one of their main drawbacks. The SPM speed barrier can be improved by operating a number of probes in parallel mode. A key element when developing probe array devices is a convenient read-out system for measurements of the probe deflection. Such a read-out should be sufficiently sensitive, resistant to the working environment, and compatible with the operation of large number of probes working in parallel. In terms of fabrication, the geometrical uniformity i.e. the realisation of large numbers of identical probes, is a major concern but also the material choice compatible with high sensitivity, the detection scheme and the working environment is a challenging issue. Examples of promising applications using parallel SPM are dip-pen-nanolithography, data storage, and parallel imaging.

We consider two self-avoiding polygons (2SAPs) each of which spans a tubular sublattice of ℤ³. A pattern theorem is proved for 2SAPs, that is any proper pattern (a local configuration in the middle of a 2SAP) occurs in all but exponentially few sufficiently large 2SAPs. This pattern theorem is then used to prove that all but exponentially few sufficiently large 2SAPs are topologically linked. Moreover, we also use it to prove that the linking number Lk of an n edge 2SAP G_n satisfies lim_n→∞ℙ(|Lk(G_n)| ≥ f(n))=1 for any function . Hence the probability of a non zero linking number for a 2SAP approaches one as the size of the 2SAP goes to infinity. It is also established that, due to the tube constraint, the linking number of an n edge 2SAP grows at most linearly in n.

Shape memory polymer composite (SMPC) structures, due to their ability to be formed into a small compact volume and then transform back to their original shape, are considered as a solution in the design of light-weight large deployable space structures. There is a wide array of constitutive and qualitative work being done on SMPC’s but little or no development of dynamic equations. This paper documents a macroscopic model for the shape fixation and shape recovery processes of a SMPC cantilever beam. In particular the focus is on the shape fixation process, whereby a quasi-static equilibrium model can be used instead of a full equation of motion. Numerical results are obtained in this regard by use of finite difference approximation with Newton’s method. This formulation combines a nonlinear geometric model with a temperature dependent constitutive law. Additionally, the dynamic equations of the SMPC cantilever are derived. Future work will include a dynamic numerical model, and a finite element model of the SMPC structure.

In this project, nanocomposite films were prepared with different Titanium dioxide (TiO₂) percentages. Properties of polycarbonate (PC) and PC–TiO₂ nanocomposite films were studied by X-ray diffraction (XRD) analysis and Fourier transform infrared (FTIR) spectroscopy. The structure of samples was studied by XRD. The mechanical properties of PC–TiO₂ nanocomposite films were investigated by conducting tensile tests and hardness measurements. Thermal stability of the nanocomposites was studied by thermogravimetric analysis (TGA) method. The elastic modulus of the composite increased with increasing weight fraction of nanoparticles. The microhardness value increases with increasing TiO₂ nanoparticles. The results of tensile testing were in agreement with those of micro-hardness measurements. In addition, TGA curves showed that nanocomposite films have higher resistance to thermal degradation compared to polycarbonate. There are many reports related to the modification of polycarbonate films, but still a systematic study of them is required.

Polymer and polymer-based composites are widely used in the electronic packaging industry. There is a need to shorten the processing time for cost-effective reasons. Microwave radiation is recognized as an alternative to the conventional thermal treatment. This paper presents the fundamental concept of MW used as heating source for curing polymers. Upon literature survey, comparison between thermal and MW approaches was given. Various variables affecting MW applications were analyzed. Metal effect under microwave radiation was also discussed corresponding to the metal-filled electrically conductive adhesives. At last, a conclusion was made that microwave as the source of energy can offer higher processing rate than thermal treatment while no adverse effect is exerted on the properties of the processed materials; an even higher heating rate will require considerations of the influence of various variables; metal-filled electrically conductive adhesives could be heated with variable frequency microwave with no arcing being incurred.

This paper contains selected topics from four lectures given at the Abdus Salam International Centre for Theoretical Physics in May 2009. We introduce the study of the influence of knotting and linking on the spatial characteristics of linear and ring polymer chains with examples of scientific interest. We describe a few basic concepts of the geometry and topology of knots and measures of the spatial shape of open and closed polymer chains. We then present some fundamental mathematical results concerning them. Next we discuss random sampling methods of collections of open and closed chains that are employed to provide estimates of the spatial properties of the chains. Finally, we discuss implementations of the sampling algorithms, survey consequences of theoretical and experimental results, and discuss some interesting problems deserving further research.