A cutting and scheduling problem in float glass manufacturing

This paper considers a cutting and scheduling problem of minimizing scrap motivated by float glass manufacturing and introduces the float glass scheduling problem. We relate it to classical problems in the scheduling literature such as no-wait hybrid flow shops and cyclic scheduling. We show that the problem is NP-hard, and identify when each of the problem’s components are polynomially solvable and when they induce hardness. In addition, we propose a simple heuristic algorithm, provide its worst-case performance bounds, and demonstrate that the bounds are tight. When the number of machines is two, the worst-case performance is 5/3.     

Endosonographic, endoscopic, and histologic evaluation of alterations in the rectal venous system in patients with portal hypertension

BACKGROUND: Colorectal varices and congestive rectopathy or colopathy have been erratically reported in patients with portal hypertension. The clinical importance of these entities has not been described. We assessed the changes in the venous system of the rectum by endoscopy and rectal endosonography (EUS). We also assessed the role of factors such as etiology of portal hypertension, grade of esophageal varices, sclerotherapy, and liver disease severity on the occurrence of these vascular changes. METHODS: We studied changes in the venous system of the rectum using endoscopy and EUS in 60 patients with portal hypertension (cirrhotic 41, noncirrhotic 19). Ten patients with irritable bowel syndrome and 6 patients with hemorrhoids served as controls. Rectal varices were classified as tortuous, nodular, and tumorous. Corresponding appearances on rectal EUS were classified as single or discrete multiple, multiple, and innumerable submucosal veins, respectively. Evidence of congestive rectopathy was also recorded. RESULTS: Prevalence of rectal varices was 43.3% on endoscopy (73% tortuous, 19% nodular, and 8% tumorous) and 75% on EUS (p < 0.0005). The latter showed corresponding appearances of submucosal veins in 25 of 26 patients and detected submucosal veins not identified at endoscopy in 19 other patients. Congestive rectopathy was found in 38.3% of patients. Multiple small dilated vessels in the submucosa were seen in 23.3% patients on rectal EUS. The development of these vascular changes was significantly influenced by sclerotherapy, but not by higher grade of esophageal varices, the etiology of portal hypertension, or severity of liver disease. CONCLUSIONS: Changes in the rectal venous system are common, with rectal EUS being superior to endoscopy in detecting early, as well as florid, changes.     

The Gut-Skin Microbiota Axis and Its Role in Diabetic Wound Healing—A Review Based on Current Literature

Diabetic foot ulcers (DFU) are a growing concern worldwide as they pose complications in routine clinical practices such as diagnosis and management. Bacterial interactions on the skin surface are vital to the pathophysiology of DFU and may control delayed wound healing. The microbiota from our skin directly regulates cutaneous health and disease by interacting with the numerous cells involved in the wound healing mechanism. Commensal microbiota, in particular, interact with wound-repairing skin cells to enhance barrier regeneration. The observed microbes in DFU include Staphylococcus, Streptococcus, Corynebacterium, Pseudomonas, and several anaerobes. Skin commensal microbes, namely S. epidermidis, can regulate the gamma delta T cells and induce Perforin-2 expression. The increased expression of Perforin-2 by skin cells destroyed S. aureus within the cells, facilitating wound healing. Possible crosstalk between the human commensal microbiome and different cell types involved in cutaneous wound healing promotes the immune response and helps to maintain the barrier function in humans. Wound healing is a highly well-coordinated, complex mechanism; it can be devastating if interrupted. Skin microbiomes are being studied in relation to the gut-skin axis along with their effects on dermatologic conditions. The gut-skin axis illustrates the connection wherein the gut can impact skin health due to its immunological and metabolic properties. The precise mechanism underlying gut-skin microbial interactions is still unidentified, but the immune and endocrine systems are likely to be involved. Next-generation sequencing and the development of bioinformatics pipelines may considerably improve the understanding of the microbiome-skin axis involved in diabetic wound healing in a much more sophisticated way. We endeavor to shed light on the importance of these pathways in the pathomechanisms of the most prevalent inflammatory conditions including the diabetes wound healing, as well as how probiotics may intervene in the gut-skin axis.     

First Application of Mix Metallic Salt Mordant Combinations to Develop Newer Shades on Wool with Bixa orellana Natural Dye Using Reflectance Spectroscopy

Annatto colorants derived from Bixa orellana L. seeds have been extensively used in a wide range of food commodities such as dairy products, flour confectionery, fish, soft drinks, meat products, snack foods, and dry mixes. To exploit its use as a colorant for textiles, this research study investigates for the first time pre-mordanting of wool with bi and tri metal salt combinations using aluminum potassium sulfate, ferrous sulfate, and stannous chloride mordants in order to develop natural and beautiful shades on wool with variation in hue and tone. The dyeing was carried by exhaustion method and dyed samples were analyzed using a Reflective Spectrophotometer in terms of CIELAB (L*, a*and b*) and K/S values and washing and light fastnesses were investigated according to I.S.O. standard recommendations. In the dyeing experiments, wool samples pre-mordanted with Fe + Sn displayed highest color strength followed by Fe + Al and Al + Sn combinations. The results showed that overall 36 different shades having good to very good fastness properties were produced by the use of different metallic salt combinations in the natural dyeing of wool using annatto dye.     

Environmental sustainability assessment of bio-ethanol production in Thailand

Bio-ethanol is playing an important role in renewable energy for transport according to Thai government policy. This study aims to evaluate the energy efficiency and renewability of bio-ethanol system and identify the current significant environmental risks and availability of feedstocks in Thailand. Four of the seven existing ethanol plants contributing 53% of the total ethanol fuel production in Thailand have been assessed by the net energy balance method and Life Cycle Assessment (LCA). A renewability and net energy ratio portfolio has been used to indicate whether existing bio-ethanol production systems have net energy gain and could help reduce dependency on fossil energy. In addition, LCA has been conducted to identify and evaluate the environmental hotspots of ‘cradle to gate’ bio-ethanol production. The results show that there are significant differences of energy and environmental performance among the four existing production systems even for the same feedstock. The differences are dependent on many factors such as farming practices, feedstock transportion, fuel used in ethanol plants, operation practices and technology of ethanol conversion and waste management practices. Recommendations for improving the overall energy and environmental performance of the bio-ethanol system are suggested in order to direct the bio-ethanol industry in Thailand towards environmental sustainability.     

Facile synthesis of doped ceria-based oxide by co-precipitation technique and performance evaluation in solid oxide fuel cell

Co-precipitated nanocrystalline gadolinium (Gd)-doped ceria (CeO₂) has been synthesized with varying mole ratios of Gd in CeO₂ from 0.1-0.8 with intricate maintenance of solution pH. Phase pure Gd-doped CeO₂ (CGO) is obtained after calcination at 750°C and depending on the mole % dopant concentration, the typical crystallite size is found to vary in the range 9-27 nm. Careful observation reveals that, calcined particle size decreases with the decrease in Gd content and an optimization of the particle size with exposed (111) [stable] and (100) plane [reactive] happens to occur for Ce_0.8Gd_0.2O_2−δ (CG_0.8). High resolution transmission electron micrograph of CG_0.8 reveals highly interpenetrating lattice planes corresponding to cubic fluorite structure. The effectivity of such CG_0.8 is further supported by its high electrical conductivity of 0.02 and 0.105 S/cm @ 600 and 700°C respectively. The bulk impedances exhibit ohmic (R₀) and interfacial (R_p) polarizations to be 146 and 29.96 Ω cm² at a temperature of 600 and 700°C with activation energies 0.36 and 0.8 eV respectively. The application of CG_0.8 is further established as an interlayer in nickel oxide-yittria stabilized zirconia (NiO-YSZ)/YSZ/CGO/La-Sr-Co-Fe-based single cell with a current density of 1.2 A/cm² @ 0.5 V and 700°C using hydrogen as the fuel and oxygen as the oxidant.     

All ambient environment‐based perovskite film fabrication for photovoltaic applications

Low‐temperature solution process‐able perovskite solar cells are highly desirable for future photovoltaics. Chemical root was utilized to synthesize and optimize mixed halide‐based MAPbIBr₂ light absorber perovskites on electron transport layer of TiO₂ nanoparticles in ambient atmosphere. For the first time all synthesis work was performed in an ambient environment and observe material behavioral characteristics. To accurately control the film morphology, one‐step deposition technique was applied to investigate material's optoelectronic behavior. The role of the perovskite structure, physical, and optical properties in planner device architecture was studied through ultraviolet visible, X‐ray diffraction, X‐ray photoelectron spectroscopy, and scanning electron microscope characterization techniques to confirm a band gap of 1.76 eV with cubic crystalline structure having a particle size of 12.5–13.0 nm, which is highly suitable for perovskite solar cells.     

Monitoring urban transport air pollution and energy demand in Rawalpindi and Islamabad using leap model

A research associated with urban transportation was carried out in Rawalpindi and Islamabad to analyze the status of emission of air pollutants and energy demands. The study included a discussion of past trends and future scenarios in order to reduce the future emissions. A simple model of passenger transport has been developed using computer based software called Long-Range Energy Alternatives Planning System (LEAP). The LEAP model was used to estimate total energy demand and the vehicular emissions for the base year 2000 and extrapolated till 2030 for the future predictions. Transport database in Rawalpindi and Islamabad, together with fuel consumption values for the vehicle types and emission factors of NO_x, SO₂ and PM₁₀ corresponding to the actual vehicle types, formed the basis of the transport demand, energy consumption and total emission calculations. Apart from base scenario, the model was run under three alternative scenarios to study the impact of different urban transport policy initiatives that would reduce energy demand and emissions in transport sector of Rawalpindi and Islamabad. The prime objective was to arrive at an optimal transport policy, which limits the future growth of fuel consumption as well as air pollution.     

Mechanical properties of functionalized SEBS based inorganic hybrid materials

Summary Functional triblock copolymer [polystyrene-b-poly(ethylene-ran-butylene)-b-polystyrene] or SEBS elastomer was used to synthesize flexible organic-inorganic hybrid materials. Modification of elastomer was first achieved via nitration to produce nitrofunctionalized copolymer and its subsequent reduction forming aminofunctionalized copolymer. IR, ¹H NMR and ¹³C NMR spectroscopic analyses provided an evidence of their modified structures. Modified SEBS based hybrid materials were then prepared through solution intercalation technique using layered silicates and in-situ polymerization of metal alkoxides via sol-gel process. In the first attempt, hybrids were prepared by the reinforcement of aminofunctionalized SEBS with organophilic montmorillonite to establish compatibility between organic matrix and inorganic phase. Reinforcement of the modified copolymer was secondly achieved by hydrolytic condensation of tetraethoxysilane using 3-glycidyloxypropyl trimethoxysilane (as a coupling agent) yielding hybrid materials. The chemical interactions between the organic polymer chains and the inorganic networks produced in-situ led to better properties of modified elastomer. Mechanical properties of thin transparent films of these hybrids were measured. Tensile strength of hybrids shows a considerable improvement over pure SEBS as well as aminofunctionalized copolymer in all the systems, which shows an increased interfacial interaction between organic and inorganic phases.