Phonon-Induced Rabi-Frequency Renormalization of Optically Driven Single InGaAs/GaAs Quantum Dots

The authors thank the EPSRC (U.K.) EP/G001642, and the QIPIRC U.K. for financial support. A. N. is supported by the EPSRC and B.W. L. by the Royal Society.We study optically driven Rabi rotations of a quantum dot exciton transition between 5 and 50 K, and for pulse areas of up to 14 pi. In a high driving field regime, the decay of the Rabi rotations is nonmonotonic, and the period decreases with pulse area and increases with temperature. By comparing the experiments to a weak-coupling model of the exciton-phonon interaction, we demonstrate that the observed renormalization of the Rabi frequency is induced by fluctuations in the bath of longitudinal acoustic phonons, an effect that is a phonon analogy of the Lamb shift.Peer reviewe

Satlc model lesson for teaching and learning complex environmental issues related to the thermodynamics

Environmental chemistry is one of the disciplines of Science. For the goal of the deep learning of the subject, it is indispensable to present perception and models of chemical behaviour explicitly. This can be accomplished by giving careful consideration to the development of concepts such that newer approaches are given contemplation, taking in consideration participation of students. Students, well versed in issues which integrate to enhance vital concepts, are thus able to understand nature and help us to discover means to view the impact of industrialization on the well being of mankind. Understanding environmental chemistry needs quality teaching at undergraduate stage of students learning. In the absence of necessary input of biological sciences, mathematics, statistics, along with the parameters of analytical and physical chemistry, students often find environmental chemistry a difficult subject. It is therefore desirable that the practice of disseminating knowledge related to environmental chemistry must avoid the tradition of presenting the necessary information separated from each other. The lectures should be designed in such a way that they provide the complete description of any issue debated in the class room. The students have not to be encouraged to address the issue in a sphere of limited knowledge. It is suggested that the teachers organize their lectures in such a way that the student get involved in the class. This essential scenario can only develop when the knowledge is transferred through Systemic diagrams. Recently concept based teaching methodology; namely systemic approach to teaching and learning chemistry (SATLC) has been employed to highlight the connectivity between some environmental issues and the disciplines of Physical Chemistry. [African Journal of Chemical Education—AJCE 5(2), July 2015

Macrocyclic cyanocobalamin (vitamin B12) as a homogeneous electrocatalyst for water oxidation under neutral conditions

Highly water-soluble cyanocobalamin (also known as vitamin B-12) is the most structurally macrocyclic complex comprising cobalt in the center of a corrin ring. Interestingly, it acts as a robust electrocatalyst in water oxidation at similar to 0.58 V overpotential with a faradaic efficiency of 97.50% under neutral buffered conditions. The catalyst is impressively stable even after long-term bulk electrolysis, and homogeneous in nature, as established by a series of experiments and characterization techniques

Colorectal Cancer Screening Behaviors among American Indians in the Midwest

Colorectal cancer is the second most diagnosed cancer among American Indians and is also the second leading cause of cancer death. We used a community-based participatory approach to conduct a mixed methods study to examine colorectal cancer screening behaviors. Here we report on the screening behaviors of our focus group participants (n=153). There were significant gender differences in the colorectal cancer screening rates for FOBT and colonoscopy. Although over 80% of participants reported having health insurance, only 35% of males over 50 years old and 57% of females reported ever having a colonoscopy. More research is needed to identify the causes of gender differences in colorectal cancer screening rates among American Indians. The results of the current study provide new information on the prevalence of colorectal cancer screening among American Indians living in the Midwestern (Kansas and Missouri) portion of the country

Life assessment prognostic modelling for multi-layered coating systems using a multidisciplinary approach

The multi-disciplinary approach has been adopted to model the formation and propagation of blistering effect for evaluation of useful coating life in the multi-layered coating-substrate system. Prognostic model of de-bonding driving force has been formulated as a function of material science, solid mechanics and fracture mechanics properties to estimate critical, safe and fail conditions of the coating-substrate system. The blister growth velocity rate is also included in the developed model to estimate the blister propagation as a function of diffusion-induced stress and residual stress. The proposed prognostic modelling for the formation and propagation of blistering effect are combined to form an assessment model for evaluation of useful coating life of the multi-layered coating-substrate system and validated through experimental observation

Dynamic Creep Performance of Hot Mix Asphalt Mixture Incorporating Fibre

Permanent deformation is one of the distress that develops gradually as the number of load applications increases and appears as longitudinal depressions in the wheel paths and small upheavals to the sides. For this reason, numerous studies conducted on modification asphalt binder or mixture by various fibre. This paper presents the evaluation of creep modulus and permanent deformation of modified asphalt mixture with fibres. In order to envisage the modified asphalt mixture, Forta-fi, Kenaf and PET was blended to estimate the creep properties and rut depth value at different loading pattern. Superpave mix design method was employed with NMAS 12.5mm to obtain the optimum bitumen content established at 4% air void. In the respect, bitumen 60/70 penetration grade with 0.5% of Forta-Fi, 0.1% Kenaf fibre and 0.5% PET by weight of asphalt mixture were prepared. Dynamic Creep Test was performed in accordance to the EN 12697-25:2005 guidelines using the Universal Testing Machine (UTM). As the result, the minimum value of permanent deformation was found at 0.5% of PET. Based on these studies, adding a minimum percent of PET in the asphalt mixture shows a better resistance to rutting deformation and enable a better understanding of the properties in modified asphalt mixtures

Dynamic Creep Performance of Hot Mix Asphalt Mixture Incorporating Fibre

Permanent deformation is one of the distress that develops gradually as the number of load applications increases and appears as longitudinal depressions in the wheel paths and small upheavals to the sides. For this reason, numerous studies conducted on modification asphalt binder or mixture by various fibre. This paper presents the evaluation of creep modulus and permanent deformation of modified asphalt mixture with fibres. In order to envisage the modified asphalt mixture, Forta-fi, Kenaf and PET was blended to estimate the creep properties and rut depth value at different loading pattern. Superpave mix design method was employed with NMAS 12.5mm to obtain the optimum bitumen content established at 4% air void. In the respect, bitumen 60/70 penetration grade with 0.5% of Forta-Fi, 0.1% Kenaf fibre and 0.5% PET by weight of asphalt mixture were prepared. Dynamic Creep Test was performed in accordance to the EN 12697-25:2005 guidelines using the Universal Testing Machine (UTM). As the result, the minimum value of permanent deformation was found at 0.5% of PET. Based on these studies, adding a minimum percent of PET in the asphalt mixture shows a better resistance to rutting deformation and enable a better understanding of the properties in modified asphalt mixtures

Effect of weathering on disintegration and shear strength reduction of clay shale

Frequent and strong atmosphere and hydrosphere reactions accelerate weathering of clay shale. This study was carried out to determine the effects of frequent natural drying and wetting-drying cycles on clay shales in every 8 days until the value of disintegration ratio, DR reached zero (completely non-durable). Clay shale samples from Semarang-Bawen and Hambalang were tested in the laboratory under four circumstances: (1) without soaking, (2) soaked once in every 8 days, (3) soaked 2 times in every 8 day and (4) soaked 3 times in every 8 days. Disintegration ratio, DR was obtained from the change in grain size distribution of the clay shale due to weathering. Reductions in shear strength of the samples were observed after subjected to wetting-drying cycles. The DR of Semarang-Bawen clay shale reached zero after 32 days, while the DR of Hambalang clay shale showed a range of values between 0.09 and 0.147 on the 80th day. Wetting-drying cycles showed greater impact than natural drying on shear strength parameters reduction. Triaxial tests could only be performed on samples from Semarang-Bawen and Hambalang which were exposed to wetting-drying cycles up to 24 and 32 days of test, respectively beyond which the samples completely disintegrated