Kinetics of Cd, Co and Ni Adsorption from Wastewater using Red and Black Tea Leaf Blend as a Bio-adsorbent

Every year there is deterioration in water quality. This is due to human activity. The current environmental strategies of many countries motivate the scientific community to develop reliable, economically viable and environmentally friendly technologies that are able to remove pollutants from the environment, including water. The study purpose is to determine of influence regularity of the bio-adsorbent composition and amount, which consists of red and black tea leaves mixture, on the Cd, Co and Ni adsorption process based on experimental data. As well as determine the most rational bio-adsorbent dose and the necessary red and black tea dose in bio-adsorbent to achieve MPC of heavy metals, with which process duration will be minimal. Initially, to study the adsorption process kinetics, the nature of the curve that describes the obtained experimental values was visually analyzed. To determine the adsorption process kinetic regularity, which most adequately and reliably describes the experimental data and to determine the values of the coefficients in the exponential regularity, the least squares method was used. It was observed that for Cd and Co, an increase in the black and red tea amount leads to a drastic reduction of the adsorption process time (up to 10 times); while for Ni the black tea addition slows down the adsorption process. Ni adsorption is the most complex and for certain bio-adsorbent composition values, complete Ni removal cannot be achieved in a technologically reasonable adsorption time. The technological process of Cd, Co and Ni adsorption can be expedient, if it is carried out in several stages with optimal red and black tea amounts for each of the metals. Adsorption process kinetic regularity, which was determined, can be used to calculate of adsorption process technological parameters in values wide range

A two-phase approach for real-world train unit scheduling

A two-phase approach for the train unit scheduling problem is proposed. The first phase assigns and sequences train trips to train units temporarily ignoring some station infrastructure details. Real-world scenarios such as compatibility among traction types and banned/restricted locations and time allowances for coupling/ decoupling are considered. Its solutions would be near-operable. The second phase focuses on satisfying the remaining station detail requirements, such that the solutions would be fully operable. The first phase is modeled as an integer fixed-charge multicommodity flow (FCMF) problem. A branch-and-price approach is proposed to solve it. Experiments have shown that it is only capable of handling problem instances within about 500 train trips. The train company collaborating in this research operates over 2400 train trips on a typical weekday. Hence, a heuristic has been designed for compacting the problem instance to a much smaller size before the branch-and-price solver is applied. The process is iterative with evolving compaction based on the results from the previous iteration, thereby converging to near-optimal results. The second phase is modeled as a multidimensional matching problem with a mixed integer linear programming (MILP) formulation. A column-and-dependentrow generation method for it is under development

Mother-to-child transmission of human immunodeficiency virus in Italy : temporal trends and determinants of infection

In order to analyse temporal trends in vertical transmission rates of human immunodeficiency virus (HIV) and determinant of congenital HIV infection in Italy, we have considered data from a network of hospitals co-operating in the Italian Collaborative Study on HIV infection in pregnancy, conducted between 1988 and 1995. A total of 1040 women entered the study. The HIV-1 status of the babies was known in 848 cases (81.5%). Transmission rates were highest in the period 1988\u20131991, then tended to decrease and in 1995 the rate was 9.7 per 100 children (this finding, however, was based on only six infected children and the trend was not statistically significant). Considering the overall series, the risk of vertical HIV transmission was higher in women with low CD4 count in pregnancy [odds ratio (OR) <400 versus \u2a7e400 1.8, 95% confidence interval (CI) 1.1\u20132.9]. In comparison with vaginal delivery the risk of transmission was 0.3 (95% CI 0.1\u20130.5) and 0.6 (95% CI 0.3\u20131.2) respectively for elective and emergency delivery. In comparison with women who delivered at term (\u2a7e37 gestation weeks) the OR of HIV infection of the babies for the whole series was 2.2 (95% CI 1.3\u20133.6) in women who delivered preterm. Similar findings emerged when the analysis was conducted considering, separately, subjects observed in the period 1988\u20131991 and 1992\u20131995. The frequency of Caesarean section increased from 26.5% of deliveries in 1988\u20131991 to 36.2% in 1992\u20131995. Consequently, most temporal differences disappeared after standardization for mode of delivery, but the rate in 1995 was still lower than in 1988\u20131994

Black hollow TiO2 nanocubes: Advanced nanoarchitectures for efficient visible light photocatalytic applications

Black hollow nanocubic TiO2 (BHC-TiO2) architectures have been synthesized via multi-step approach comprising co-precipitation to prepare hematite nanocubes; titania covering of hematite towards Fe2O3/TiO2 core/shell nanocubes and hydrothermal hematite etching process to yield hollow cubic TiO2 structures with Ti3+ species after high temperature hydrogen treatment. The resultant BHC-TiO2 nanoarchitectures exhibited excelling photocatalytic performance under visible light in the preparation of benzimidazole derivatives. This superior activity can be attributed to the design of BHC-TiO2 with high surface area (⁓206 m2g−1), ultrathin shell (⁓50 nm), hydrogenated visible active structure and void nanoreactor-like space in the cubic structure. © 2018 Elsevier B.V

Engineered bi-functional hydrophilic/hydrophobic yolk@shell architectures: A rational strategy for non-time dependent ultra selective photocatalytic oxidation

Engineered graphene highly wrapped yolk@shell TiO2 (G-HW-Y@S-TiO2) architectures were synthesized from fundamental understanding using a multi-step approach as advanced photocatalytic nanomaterials. The resultant G-HW-Y@S-TiO2 architecture exhibited a superior selective photocatalytic performance in visible light oxidation of aromatic alcohols to corresponding aldehydes (up to 99% in 4 h reaction). Interestingly, the aldehyde was still obtained as single oxidation product after 12 h in presence of G-HW-Y@S-TiO2 structure. The observed non-time dependent photocatalytic oxidation selectivity can be attributed to the engineered photocatalyst architecture with different hydrophilic level sites between inner core and outer shell that force the hydrophobic aldehyde products to diffuse out from the hydrophilic void space preventing further over-oxidation. © 201

The phenomenology of the quantum-corrected gravitational force

The Newtonian gravitational force can be derived from the Heisenberg uncertainty principle. In the realm of high-energy physics, it is necessary to replace the standard uncertainty principle by the generalized uncertainty principle (GUP). The generalized uncertainty principle can provide some corrections into the gravitational force. In this paper, we have applied the GUP to modify the gravitational force. The modified gravitational force has been applied to find the GUP corrections into Binet's equation. The modified Binet's equation has been used to study the advance of the perihelion of Mercury. It is shown that the GUP may provide the precession of Mercury's perihelion in the context of Newtonian physics. The modified gravitational force can also be applied to find the modified Friedmann equation in which the correction terms may play the role of dark energy to provide an accelerating universe

Black hollow TiO2 nanocubes: Advanced nanoarchitectures for efficient visible light photocatalytic applications

Black hollow nanocubic TiO2 (BHC-TiO2) architectures have been synthesized via multi-step approach comprising co-precipitation to prepare hematite nanocubes; titania covering of hematite towards Fe2O3/TiO2 core/shell nanocubes and hydrothermal hematite etching process to yield hollow cubic TiO2 structures with Ti3+ species after high temperature hydrogen treatment. The resultant BHC-TiO2 nanoarchitectures exhibited excelling photocatalytic performance under visible light in the preparation of benzimidazole derivatives. This superior activity can be attributed to the design of BHC-TiO2 with high surface area (⁓206 m2g−1), ultrathin shell (⁓50 nm), hydrogenated visible active structure and void nanoreactor-like space in the cubic structure. © 2018 Elsevier B.V

Designer hydrogenated wrinkled yolk@shell TiO2 architectures towards advanced visible light photocatalysts for selective alcohol oxidation

Smart architectures of TiO2 are attracting increasing attention due to their outstanding properties in a broad range of fields. Herein, we report the preparation of an unprecedented yolk/shell wrinkled TiO2 architecture with excellent photocatalytic activities under visible light irradiation. This method includes solvothermal, partial etching and hydrogen treatment sequential preparation steps. The solvothermal step leads to yolk@shell TiO2 (Y@S-TiO2) structures which can generate multiple reflections of incident light so as to promote an efficient light harvesting due to an enhanced surface area and light scattering ability based on the hydrothermal alkaline partial etching. The hydrogen treatment process generated Ti3+ species on the surface of TiO2 which facilitate electron-hole separation, decreasing the band gap of titania to the visible region. The resultant yolk@hydrogenated wrinkled shell TiO2 architecture exhibited high efficiency in visible light oxidation of alcohols to the corresponding aldehydes (up to 90% in conversion and 97% in selectivity). © The Royal Society of Chemistry

Enhanced exact solution methods for the Team Orienteering Problem

The Team Orienteering Problem (TOP) is one of the most investigated problems in the family of vehicle routing problems with profits. In this paper, we propose a Branch-and-Price approach to find proven optimal solutions to TOP. The pricing sub-problem is solved by a bounded bidirectional dynamic programming algorithm with decremental state space relaxation featuring a two-phase dominance rule relaxation. The new method is able to close 17 previously unsolved benchmark instances. In addition, we propose a Branch-and-Cut-and-Price approach using subset-row inequalities and show the effectiveness of these cuts in solving TOP