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In this article, the potential of amine-functionalized poly(styrene) (PS) microspheres as toughening agent for epoxy resin has been explored. PS microspheres were prepared by suspension polymerization, where the monomer concentration and stirring speed was varied to control the microsphere dimensions (52-183 µm). The obtained microspheres were chemically functionalized with an aim to improve its dispersion within the epoxy matrix. The amine groups generated on the microsphere surface offer a potential site of covalent linkage with the epoxy matrix, thereby resulting in increased compatibility and improved properties. Epoxy composites containing varying amounts of microspheres (1-7% w/w) were prepared and their mechanical properties were evaluated under both quasi-static as well as dynamic conditions. The amination of poly(styrene) (APS) led to improved dispersion of the rigid microspheres in the epoxy matrix, which was evident from higher impact strength and fracture energies (GIC) as compared to its neat analogs. The izod impact strength and GIC increased by 33% and 150%, respectively, on introduction of 3% APS. This was accompanied with an increase in the tensile modulus and strength of the epoxy resin. Further increase in loading led to agglomeration of the microspheres, which in turn resulted in lowering of impact strength and toughness. Excellent agreement was found between the experimentally measured modulae and the predictions made on the basis of Halpin-Tsai and Lewis-Neilson models. Fracture surface morphology was studied to arrive at the principal toughening mechanisms behind the experimental findings. POLYM. COMPOS., 36:174-183, 2015. © 2014 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

In this paper, we report the degradation behavior of a LDPE-grafted Maleic anhydride polymer prepared using a reactive extrusion technique. 70 ± 5 µm blown films were exposed to oxidative environments, and the degradation was followed by monitoring physico-chemical and morphological changes. The studies indicated that grafting with Maleic anhydride does not affect the degradation characteristics of the base polymer. Kinetic parameters of degradation, as estimated using non-isothermal TGA, were used to estimate the theoretical lifetime of the polymers, which remained unaltered due to grafting. The results, however, indicated that cobalt stearate, a typical pro-oxidant, led to massive degradation during thermal processing. [ABSTRACT FROM PUBLISHER]

Because of the presence of carboxylic acid moieties, poly(acrylic acid) possesses a unique ability to form stable complexes with divalent metal ions. However, its practical use for the removal of heavy metals from aqueous solutions is restricted because of its inherent water solubility. To address this issue, crosslinking of this polymer has been attempted to synthesize hydrogel, which is stable in aqueous medium over a wide range of pH values. The hydrogels, prepared by redox polymerization of acrylic acid in the presence of polyethylene glycol diacrylate as the crosslinker, were characterized by Fourier transform infrared spectrometry, elemental analysis, thermal analysis, and swelling studies. This chelating hydrogel-bearing O, O donor groups exhibited high-metal sorption capacity of 41.1, 58.2, 43.1, and 81.2 mg/g for Cr6+, Ni2+, Cu2+, and Pb2+, respectively, under optimum conditions. The effect of parameters including pH, concentration, and interference of common ions on metal uptake was also investigated. Langmuir and Freundlich adsorption isotherms have been used to validate the metal uptake data. High recovery (>97%) was achievable for all metal ions with 1 N HCl as eluting agent, and the regeneration tests revealed that the sorbent could be used repeatedly for at least 10 cycles without any loss in chelating efficiency. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011. [ABSTRACT FROM AUTHOR]

Polyethylene wastes, particularly as films, have accumulated over the last several decades resulting in a major visual litter problem. The aim of this study was to investigate the ability of chemical reagents to oxidize the low-density polyethylene (LDPE) film surface to increase their susceptibility toward photodegradation and thermal degradation. Three chemical agents, namely, potassium permanganate, potassium persulfate, and benzoyl peroxide, were used to oxidize the film surface to generate chromophoric groups, such as carbonyl groups, which are the main reason for the enhanced environmental degradation of photolytic polymers, such as ethylene-carbon monoxide and ethylene-vinyl ketone copolymers. For the chemical treatment, LDPE films of 70 ± 5 μm thickness were prepared by a film-blowing technique and subsequently reacted with the aforementioned oxidizing agents. To aid the oxidation process, the reaction with potassium persulfate and potassium permanganate was performed under microwave irradiation heating. In the case of benzoyl peroxide aided oxidation, the films were subjected to repeated coating-heating treatments up to a maximum of 10 cycles. The treated films were subjected to accelerated aging, that is, xenon-arc weathering and air-oven aging (at 70°C), for extended time periods. The chemical and physical changes induced as a result of aging were followed by the monitoring of changes in the mechanical, structural, and thermal properties. The results indicate that the surface-oxidized LDPE films exhibited enhanced susceptibility toward degradation; however, the extent was reduced as compared to photolytic or other degradable compositions. The ability of the chemicals to initiate degradation followed the order potassium persulfate < potassium permanganate < benzoyl peroxide. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 [ABSTRACT FROM AUTHOR]

With the current state of the global economy, demand for various products plummeting. To sustain in the market, companies have to reduce cost and improve quality. Today, companies have started implementing new philosophies like TQM, TPM, six sigma and lean manufacturing techniques to remain competitive in the market. Lean manufacturing is an emerging philosophy which continuously strives to reduce waste. The main objective of analyzing the assembly line with a lean perspective is to identify the areas related to human interface with other systems that could lead to the generation of waste. Improper workplace design leads to unreasonable mental or physical burden and results in waste generation like slow work (delay and inventory), and defects, which is named as muri waste. An attempt has been made in this paper to locate muri waste and create a "Lean assembly line". The proposed method, based on the use of Rapid Upper Limp Assessment (RULA) with CATIA V5 platform, has allowed the measurement of a large set of operator posture parameters and assessment of ergonomic stresses. Based on the results, the process stations in the assembly line were redesigned to prevent the generation of waste. [ABSTRACT FROM AUTHOR]

The article discusses research on the thermooxidative and photooxidative degradation behavior of linear low-density polyethylene (LLDPE) films in the presence of cobalt stearate. The study procedure included air-oven aging tests and xenon arc weathering. The researchers also monitored changes in melt flow index, morphology, and carbonyl index. It was found that the photoinitiating and thermoinitiating activities of cobalt stearate rose with increasing prooxidant concentration.

Wastewaters discharged from the defence serviceable industries pose a serious environmental hazard due to their heavy metal load. The present study focused on optimizing the operational variables viz, hydraulic loading rate, bed height and feed concentration through bench scale study and using that for assessing the efficiency of pilot scale system with sulphur loaded carbon (AC-S) as the adsorbent in the removal of Pb (II). Static mode adsorption studies were also carried out for Pb (II) removal using treated (AC-S) and untreated carbon (AC). AC-S shows about 35 percent increase in maximum adsorption capacity over that on AC. The maximum adsorption capacity in the column mode for Pb (II) at the optimized conditions: bed height of 0.4 m, hydraulic loading rate of 7.5 m3h-1m-2 and the feed concentration of 6 mg l-1 for achieving 50 % breakthrough concentration was found to be 2.89 mg g-1. Adsorption mechanism involved during Pb (II) in the column has also been explored. Bohart - Adams model was used for modeling the bench scale data and predicting the adsorption behavior at pilot scale level. [ABSTRACT FROM AUTHOR]

This study was undertaken to investigate adsorption behavior of Hg (II) from aqueous systems on activated carbon in static and dynamic mode by varying initial Hg (II) concentration, adsorbent dose and pH. Langmuir and Freundlich adsorption isotherm were applied to model the adsorption data. Removal of mercury obeyed the Langmuir and Freundlich adsorption isotherm models. The extent of removal of Hg (II) was found to be dependent on sorbent dose, pH and initial Hg (II) concentration. Mercury uptake increased from 72 to 100 percent with increasing pH from 2 to 10. A set of desorption studies was also performed for the metal ions with the aim of investigating the mechanism involved. Moreover, the competing effects of various ions like Pb (II) and Cu (II) is also described. The column capacity for a column diameter of 20 mm, bed height of 0.4 m, hydraulic loading rate of 7.5 m3h-1m-2 and a feed concentration of 3 mg I-1 were found to be 3.02 mg g-1. Breakthrough curves were plotted for the adsorption of mercury on the adsorbent using continuous-flow column operation by varying different operating parameters like hydraulic loading rate (3-10.5 m3h-1m-2), bed height (0.3-0.5 m), and feed concentrations (2-6 mg I-1). The aim was to assess the effect of bed height, hydraulic loading rate and initial feed concentration on breakthrough time and adsorption capacity, which helped in ascertaining the practical applicability of the adsorbent. At the end an attempt has been made to develop empirical relationship from the data generated from column studies for designing the adsorption column, based on the Bohart -Adams model. [ABSTRACT FROM AUTHOR]

Incubating hematopoietic stem cells with IL-2 in vitro for 24 h generates cytotoxic T cells. When infused into patients, these cells may stimulate a graft-versus-tumor (GVT) effect. This clinical trial was designed to assess the ability of IL-2 activated peripheral blood stem cells (PBSC) to reconstitute hematopoiesis, to investigate dose levels and dose-limiting toxicities of IL-2, and to evaluate clinical results and preliminary laboratory effects using a combination of IL-2-activated autologous PBSC followed by IL-2 after transplantation. Sixty-one women with stage II-IV breast cancer were treated. After the administration of carboplatin (200 mg/m²/day for 3 days) and cyclophosphamide (2 g/m²/day for 3 days), patients received autologous PBSC that were cultured in IL-2 for 24 h followed by parenteral administration of IL-2 beginning the day of transplantation. Three escalating doses of IL-2 were evaluated with increasing duration up to 4 weeks. Of the 57 patients receiving IL-2 after tranplantation, 19 patients (33.3%) were unable to complete the planned course of IL-2 therapy due to persistent fevers (n = 9), diarrhea (n = 2), pulmonary capillary leak syndrome (n = 3), development of a rash (n = 1), atrial fibrillation (n = 1), or patient's request (n = 3). One death occurred during hospitalization. Engraftment of neutrophils occurred on day 11.5 (mean; range 8-21 days) and platelets on day 11.7 (mean; range 7-33 days). The maximal tolerated dose of IL-2 was 6 x 10[sup5] IU/m²/day for 4 weeks. Disease-free survival rates for all stages were comparable to current reports in the literature. Preliminary laboratory evaluations include FACScan analysis of the IL-2... [ABSTRACT FROM AUTHOR]

For a series Σan with partial sums An=a0 + a1 + … + an(n ≥ 0), supposed to be real in this note, we define, in a generally accepted notation ([2], pp. 7, 9, 94–98), the following transforms:(C, α) sequence-transform,(H, k)sequence-transform (k = 0, 1, 2, …):(A: C, α)fnunction-transform, [ABSTRACT FROM PUBLISHER]

A 10-year-old boy with severe hereditary angio-oedema was given danazol, 200 mg each day. There was a pronounced reduction in the frequency and severity of oedema. [ABSTRACT FROM AUTHOR]