A genetic algorithm for energy-efficiency in job-shop scheduling

Many real-world scheduling problems are solved to obtain optimal solutions in term of processing time, cost, and quality as optimization objectives. Currently, energy-efficiency is also taken into consideration in these problems. However, this problem is NP-hard, so many search techniques are not able to obtain a solution in a reasonable time. In this paper, a genetic algorithm is developed to solve an extended version of the Job-shop Scheduling Problem in which machines can consume different amounts of energy to process tasks at different rates (speed scaling). This problem represents an extension of the classical job-shop scheduling problem, where each operation has to be executed by one machine and this machine can work at different speeds. The evaluation section shows that a powerful commercial tool for solving scheduling problems was not able to solve large instances in a reasonable time, meanwhile our genetic algorithm was able to solve all instances with a good solution quality.     

Montmorillonite reinforced type A gelatin nanocomposites

This study investigates the structural, morphological, thermal, and mechanical properties of type A gelatin/montmorillonite (MMT) films as a function of MMT concentration. The variations of the X‐ray diffraction pattern suggest that the structure of the nanocomposites turns from intercalated to exfoliated on increasing clay loading up to 20 wt %. Simultaneously, gelatin interaction with clay negative sheets during gelling provokes a reduction of the triple helix content of the composite films, in agreement with the reduction of the relative intensity of the 1.1 nm diffraction reflection of gelatin and of the values of denaturation enthalpy. On the other hand, the increase of the denaturation and decomposition temperatures, the significant rise of the Young's modulus, as well as the swelling decrease observed as clay content increases, demonstrate a relevant stabilizing effect of MMT on gelatin. The reinforcement action of MMT allows to utilize a relatively low concentration of the crosslinking agent genipin to further stabilize the films. The synergic action of clay and genipin prevents dissolution of the nanocomposites in aqueous solution and enhances their mechanical properties. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40301.     

Thermal stability of modified end‐capped poly(lactic acid)

The influence of functional end groups on the thermal stability of poly(lactic acid) (PLA) in nitrogen‐ and oxygen‐enriched atmospheres has been investigated in this article using differential scanning calorimetry, thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). Functional end groups of PLA were modified by succinic anhydride and l ‐cysteine by the addition–elimination reaction. PLA was synthesized by azeotropic condensation of l ‐lactic acid in xylene and characterized by nuclear magnetic resonance. The values of the activation energies determined by TGA in nitrogen and oxygen atmospheres revealed that the character of functional end groups has remarkable influence on the thermal stability of PLA. Moreover, DMA confirmed the strong influence of functional end groups of PLA on polymer chains motion. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41105.     

Synthesis,structural and morphological characteristics,magnetic and optical properties of Co doped ZnO nanoparticles

Zn_1−xCo_xO (x==0.05, 0.10, 0.15) nanoparticles have been synthesized by an alternative wet-chemical synthesis route using the SimAdd technique. The as-obtained powders were investigated by FT-IR spectroscopy, X-ray diffraction and thermal analysis correlated with evolved gas analysis (TG–DTA–FT-IR) in order to determine their chemical nature, crystalline structure and to establish the decomposition sequences. The precipitates are generally amorphous, but low-intensity reflection peaks assigned both to the zinc oxalate dihydrate, and zinc hydroxide can be observed in the recorded patterns, indicating that hydroxy-oxalate precipitates were obtained. The structure, morphology and magnetic properties of the thermally treated samples have been investigated by X-ray diffraction, FT-IR, HRTEM, SAED, UV–vis and EPR. XRD studies reveal a hexagonal wurtzite-type structure for all Zn_1−xCo_xO samples. TEM investigations show particle size between 28 and 37 nm, with spherical and polyhedral shapes and with tendency to form aggregates. The presence of a Co₃O₄ secondary phase was evidenced by XRD, UV–vis and EPR for the Zn_0.85Co_0.15O sample. The ferromagnetic behavior of the samples was revealed. The paper highlights that by varying the cobalt concentration it is possible to modulate the structural, morphological, optical and magnetic properties.     

Physical,dynamic-mechanical and thermogravimetric analysis of aromatic and cycloaliphatic-based poly(urethaneurea)s

Experimental batches of linear rubber-like polyurethanes characterized by the presence of chemically different hard segments are studied and their thermal and dynamic-mechanical properties are related to the differences in chemical compositions. Interesting correlations are found between the development of crystallinity in such elastomeric poly(urethaneurea)s and the aromatic or alicyclic nature of the diisocyanate. Moreover, for a fixed ratio between hard and soft segments, and for a given composition of the soft segment, the results seem to indicate a better degree of phase separation in cycloaliphatic-based hard segment poly(urethaneurea)s than in aromatic-based hard segment poly(urethaneurea)s.     

Evaluation of Oxidative Stress Biomarkers,Pro-Inflammatory Cytokines,and Histological Changes in Experimental Hypertension,Dyslipidemia, and Type 1 Diabetes Mellitus

The present study aims to compare the oxidative stress biomarkers, pro-inflammatory cytokines, and histological changes induced by three cardiovascular risk factors, namely, hypertension, dyslipidemia, and type 1 diabetes mellitus. Hypertension was induced with 40 mg/kg body weight (b.w.) of N omega-nitro-L-arginine-methyl (L-NAME) administered orally. Dyslipidemia was induced by the administration of a diet with a high cholesterol (2%) content. Diabetes mellitus was induced by intraperitoneal administration of a single dose of streptozocin (65 mg/kg). Malondialdehyde (MDA) and total oxidative status (TOS) are increased by all three cardiovascular risk factors (up to 207%). The indirect assessment of NO synthesis (NOx) is observed to be reduced after L-NAME administration (43%), and dyslipidemia induction (16%), while type 1 diabetes mellitus is associated with the highest levels of NOx (increased 112%). Hypertension, dyslipidemia, and type 1 diabetes reduced the total antioxidative capacity (TAC) and total thiol (SH) levels (up to 57%). The values of evaluated pro-inflammatory cytokines, tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β), assessed from the ascending aorta were elevated by all three cardiovascular risk factors, with the highest levels induced by type 1 diabetes mellitus (up to 259%). The histopathological examination of the ascending and descending aorta revealed reversible pro-atherogenic changes consisting of the accumulation of lipid droplets in the subendothelial connective tissue on rats with hypertension and dyslipidemia. Irreversible pro-atherogenic changes consisting of a reduction of the specific elasticity of the arteries were observed in rats with type 1 diabetes mellitus. Type 1 diabetes mellitus demonstrates an alteration of the oxidative stress parameters, the elevation of tissue levels of the pro-inflammatory cytokines and causing irreversible pro-atherogenic changes on the aortic wall.     

Microstructure and mechanical properties of Al2O3/ZrO2 composites by two-step sintering

Composites of Al₂O₃/ZrO₂ (containing 25, 50, and 75 vol% ZrO₂) were prepared by mixing Al₂O₃ and ZrO₂ suspensions. The microstructural control via two-step sintering (TSS) was the main objective of this work. For this purpose, different sintering curves were constructed, aiming to achieve the best temperature combination for the sintering steps that provides higher density and finer microstructure. The results were compared with single-step sintering (SSS). Furthermore, microhardness and fracture toughness were measured for the best TSS specimens under each composition. The results showed that the high densities were obtained, and the reduction of grain size was greater than 40% for two-step sintered specimens, compared to SSS ones. Consequently, microhardness values increased. However, fracture toughness values remained unchanged.     

Role of Obesity,Physical Exercise,Adipose Tissue-Skeletal Muscle Crosstalk and Molecular Advances in Barrett’s Esophagus and Esophageal Adenocarcinoma

Both obesity and esophageal adenocarcinoma (EAC) rates have increased sharply in the United States and Western Europe in recent years. EAC is a classic example of obesity-related cancer where the risk of EAC increases with increasing body mass index. Pathologically altered visceral fat in obesity appears to play a key role in this process. Visceral obesity may promote EAC by directly affecting gastroesophageal reflux disease and Barrett’s esophagus (BE), as well as a less reflux-dependent effect, including the release of pro-inflammatory adipokines and insulin resistance. Deregulation of adipokine production, such as the shift to an increased amount of leptin relative to “protective” adiponectin, has been implicated in the pathogenesis of BE and EAC. This review discusses not only the epidemiology and pathophysiology of obesity in BE and EAC, but also molecular alterations at the level of mRNA and proteins associated with these esophageal pathologies and the potential role of adipokines and myokines in these disorders. Particular attention is given to discussing the possible crosstalk of adipokines and myokines during exercise. It is concluded that lifestyle interventions to increase regular physical activity could be helpful as a promising strategy for preventing the development of BE and EAC.     

Photocatalytic Degradation of 4,4′-Isopropylidenebis(2,6-dibromophenol) on Magnetite Catalysts vs. Ozonolysis Method: Process Efficiency and Toxicity Assessment of Disinfection By-Products

Flame retardants have attracted growing environmental concern. Recently, an increasing number of studies have been conducted worldwide to investigate flame-retardant sources, environmental distribution, living organisms’ exposure, and toxicity. The presented studies include the degradation of 4,4′-isopropylidenebis(2,6-dibromophenol) (TBBPA) by ozonolysis and photocatalysis. In the photocatalytic process, nano- and micro-magnetite (n-Fe₃O₄ and μ-Fe₃O₄) are used as a catalyst. Monitoring of TBBPA decay in the photocatalysis and ozonolysis showed photocatalysis to be more effective. Significant removal of TBBPA was achieved within 10 min in photocatalysis (ca. 90%), while for ozonation, a comparable effect was observed within 70 min. To determine the best method of TBBPA degradation concentration on COD and TOC, the removals were examined. The highest oxidation state was obtained for photocatalysis on μ-Fe₃O₄, whereas for n-Fe₃O₄ and ozonolysis, the COD/TOC ratio was lower. Acute toxicity results show noticeable differences in the toxicity of TBBPA and its degradation products to Artemia franciscana and Thamnocephalus platyurus. The EC₅₀ values indicate that TBBPA degradation products were toxic to harmful, whereas the TBPPA and post-reaction mixtures were toxic to the invertebrate species tested. The best efficiency in the removal and degradation of TBBPA was in the photocatalysis process on μ-Fe₃O₄ (reaction system 1). The examined crustaceans can be used as a sensitive test for acute toxicity evaluation.     

Carotenoids are Effective Inhibitors of in vitro Hemolysis of Human Erythrocytes,as Determined by a Practical and Optimized Cellular Antioxidant Assay

β‐Carotene, zeaxanthin, lutein, β‐cryptoxanthin, and lycopene are liposoluble pigments widely distributed in vegetables and fruits and, after ingestion, these compounds are usually detected in human blood plasma. In this study, we evaluated their potential to inhibit hemolysis of human erythrocytes, as mediated by the toxicity of peroxyl radicals (ROO?). Thus, 2,2′‐azobis (2‐methylpropionamidine) dihydrochloride (AAPH) was used as ROO? generator and the hemolysis assay was carried out in experimental conditions optimized by response surface methodology, and successfully adapted to microplate assay. The optimized conditions were verified at 30 × 10⁶ cells/mL, 17 mM of AAPH for 3 h, at which 48 ± 5% of hemolysis was achieved in freshly isolated erythrocytes. Among the tested carotenoids, lycopene (IC₅₀ = 0.24 ± 0.05 μM) was the most efficient to prevent the hemolysis, followed by β‐carotene (0.32 ± 0.02 μM), lutein (0.38 ± 0.02 μM), and zeaxanthin (0.43 ± 0.02 μM). These carotenoids were at least 5 times more effective than quercetin, trolox, and ascorbic acid (positive controls). β‐Cryptoxanthin did not present any erythroprotective effect, but rather induced a hemolytic effect at the highest tested concentration (3 μM). These results suggest that selected carotenoids may have potential to act as important erythroprotective agents by preventing ROO?‐induced toxicity in human erythrocytes.