The effect of concentration on the Surface-Enhanced Raman Scattering of p-Aminothiophenol

The organic compound p-aminothiophenol (pATP, HS-Ph-NH2) has become very popular because it is often used for checking the enhancement capability of each new SERS substrate due to its very intense SERS spectra. SERS of pATP on silver electrode is significantly different from its ordinary Raman spectra and it is very dependent on the particular conditions of the SERS experiment. In this work the effect of adsorbate concentration on the potential dependent SERS spectra of pATP recorded on a silver electrode has been studied using NaClO4 as electrolyte. On the other hand, MS-CASPT2 have been performed in order to help the analysis of the experimental results by computing resonance Raman spectra of selected structural models of the metal−adsorbate surface complex. It is found that the spectra are dependent on adsorbate concentration and dominated by a resonant charge transfer (CT) mechanism, where the charge is always transferred from the adsorbate to the metal. The relative SERS enhancements are due to Franck−Condon factors related to the CT process, and there are not intensified bands through Herzberg−Teller contributions. Furthermore, the Raman signals of the SERS recorded at low concentration arise from at least three different molecular species: (i) pATP bonded to silver electrode through sulfur atom (Agn-S−-Ph-NH2); (ii) pATP bonded to silver electrode through both sulfur and nitrogen atoms (Agn-S−-PhNH2-Agm); (iii) The azo derivative p,p′-dimercaptoazobenzene (or its nitrene precursor).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Detection of different species of p-aminothiophenol on silver nanoparticles by Surface-Enhanced Raman Spectroscopy (SERS)

In the present work we have analyzed the experimental and theoretical SERS spectra of the organic compound p-aminothiophenol (pATP, HS-Ph-NH2) recorded on silver nanoparticles. DFT calculations have been performed to support the experimental results in order to estimate the adsorption specie and the corresponding Raman bands assignment. It is found a different adsorption behavior of pATP not only by changing the concentration of the adsorbate but also by exciting the sample at different wavelengths.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Modelling shell and oscillation mark formation during continuous casting via explicit incorporation of slag infiltration

The development of reliable numerical models is vital to improve the quality of continuously cast products and to increase the productivity of the casting machine. In order to provide accurate predictions, these models must include detailed descriptions of the physical phenomena occurring inside the mould, such as metal flow, heat transfer and solidification. However, these topics are often treated separately during modelling due to their complexity. This has a negative impact on the accuracy of the predictions. To address this issue, a numerical model capable of coupling the flow dynamics with both the heat transfer to the mould walls and solidification has been developed. The 2‐dimenional model is based on a commercial CFD code that solves the Navier‐Stokes Equations coupled with a Volume of Fluid interface tracking technique for the multiphase system slag‐steel‐air under transient conditions within a conventional slab mould. The use of an extremely fine mesh in the meniscus region (~50 μm) allows, for the first time, the explicit calculation of liquid slag infiltration into the shell‐mould gap. Heat transfer through the solid mould faces and mould oscillation were also included in the model to provide a more realistic representation of the process. The model developed was tested in two case studies. In the first case, the predicted values were compared to prior numerical models and laboratory experiments directed to casting of conventional slabs. Excellent agreement was found for characteristics such as slag film development and heat flux variations during mould oscillation. Furthermore, predicted values for shell thickness, consumption and heat flux were also found to be in good agreement with plant measurements. The findings of this case study provided improved, fundamental understanding of the mechanisms involved in slag infiltration and solidification inside the mould and how these affect key process parameters, such as powder consumption and shell growth. The second case study consisted of a sensitivity study, where casting conditions (e.g. casting speed, mould cooling, steel/slag properties and oscillation settings) were varied in the simulations to determine their effect on both powder consumption and the formation of defects. The simulations predicted the initial formation of typical casting defects known as oscillation marks, without the aid of any external data fitting. The key result drawn from the sensitivity study was the determination of simple rules for the calculation of consumption, heat flux and defect formation as a function of the casting conditions. This opens the possibility of using the model as a diagnostic tool and for process optimisation

Child Abuse

In the United States, child abuse is defined as the physical maltreatment or sexual molestation of a child. Four majortypes of child abuse exist: neglect, physical, sexual, and psychological.The atrocityofchild abuse is that the abuse leaves the children with everlasting emotionalscars, and often,withphysical,cognitive, andsocial health issues. The irreversible affects such as head trauma, lower performance inschool, and poor social skills are equally as important. As the years continue, more and more children are being,and will be, abused. Overall, the importance is stopping this crime that does not need to happen

Safety margin in serviceability limit state according to the 2019 draft of Eurocode 7: Applicability to embankments on fine-grained soils.

Determination of characteristic values of soil properties is an essential step in the verification of serviceability limit states such as total settlements of embankments founded on fine-grained soils. These values provide a safety margin that accounts for sources of uncertainty such as inherent spatial variability of the properties within the soil mass and sampling uncertainty related to the extent of the investigations. However, modification of soil parameters results in deviations from the actual stress-strain behavior of soils that might be significant for certain soil conditions and characteristics. For instance, the nonlinear strains exhibited by soft Finnish clays in oedometer tests that are accounted for by the tangent modulus method. The aim of this thesis was to quantify the safety margin obtained from characteristic values in settlement calculations. Four cases from Finland with different soil conditions were analyzed. Several total settlements analyses were carried out to compare values of settlements calculated from characteristic values with values from the mean of data sets of derived soil properties (i.e., best estimates). The analyses were made as functions of the range of coefficient of variation reported in the literature for the relevant soil parameters used in the calculations. Two different deformation models were used to calculate the settlements: tangent modulus method and compression index method. The European Committee for Standardization (CEN) is planning to publish a revised version of Eurocode 7 where a statistically based equation for the determination of characteristic values will be included. This equation was used for the determination of characteristic values in this study. Likewise, an alternative equation was also used for one case in which, a purely statistical approach cannot be applied. The results show that large conservatism is induced by the strong nonlinearities of the stress-strain behavior of some soft Finnish clays when characteristic values of soil properties are used in settlement predictions. The results are especially critical for the upper bound of the range of the coefficient of variation selected. The characteristic values fail to provide a harmonized safety margin among the cases because of the different stressstrain behavior features. Therefore, characteristic values of soil parameters used in the tangent modulus method have to be estimated cautiously to avoid unnecessary safety margin. Likewise, the equation from the revised version of Eurocode 7 should be avoided in cases where limited samples are available because settlements are considerably overestimated

Future Time Perspective and Goal Setting Among College Students: A Measurement for the Dimensions of Future Time Perspective

The perceptions of the future, including attitudes, beliefs, and actions toward it, have been formalized into a construct known as Future Time Perspective (FTP). The purpose of this study was to determine if college students’ FTP was significantly different based on demographics, and to determine if the time frame of a goal (academic, professional, personal, or social) would more likely be short-term or long-term. Participants were undergraduate freshmen (first-year) and senior (fourth-year) students enrolled in Texas A&M University. Findings revealed that significant differences in FTP can be found in certain demographic variables such as sex and race, and that classification may predict the time frame in which a certain type of goal will be set. Overall, these findings can assist mentors in a university by giving them a better understanding of how their student mentees perceive the future and how likely they are to set a certain goal in a specific time frame. These attitudes of the future and the time frame differences in which goals are set may impact how successful a student is in a university

Heat inactivation of thermo-resistant bacteria isolated from poultry offal

ABSTRACT The presence of thermo-resistant bacteria in products from the rendering industry is a concern in the United States because only about 80% of the rendering industries use thermal processing to eliminate bacteria. The objective of this study was to determine the thermal inactivation characteristics of thermo-resistant bacteria from raw rendering materials. Ground beef with 21% protein, 19% fat, and 60% moisture was used as a model media to simulate raw rendering material. Raw animal co-products were heated at 91, 95, 96¡C for 90 min, then surviving bacteria were recovered. These heat resistant isolates were inoculated into meat samples then thermally treated using a dry bath incubator. Calculations for D and Z values were determined for thermo-resistant bacteria subjected to thermal treatment at 90.88¡C, 94.84¡C, and 95.90¡C. This study demonstrated that thermally resistant bacteria isolated from raw rendering materials exhibit high heat resistance for a wide range of temperature, suggesting that use of thermal processing at an optimized temperate (\u3e 96¡C) is required for an efficient removal of microbes

Simulations of GRB Jets in a Stratified External Medium: Dynamics, Afterglow Lightcurves, Jet Breaks and Radio Calorimetry

The dynamics of GRB jets during the afterglow phase is most reliably and accurately modelled using hydrodynamic simulations. All published simulations, however, have considered only a uniform external medium, while a stratified external medium is expected around long duration GRB progenitors. Here we present simulations of the dynamics of GRB jets and the resulting afterglow emission for both uniform and stratified external media with $\rho \propto r^{-k}$ for k = 0, 1, 2. The simulations are performed in 2D using the special relativistic version of the Mezcal code. The dynamics for stratified external media are broadly similar to those derived for expansion into a uniform external medium. The jet half-opening angle start increasing logarithmically with time once the Lorentz factor drops below 1/theta_0. For larger k values the lateral expansion is faster at early times and slower at late times with the jet expansion becoming Newtonian and slowly approaching spherical symmetry over progressively longer timescales. We find that contrary to analytic expectations, there is a reasonably sharp jet break in the lightcurve for k = 2 although the shape of the break is affected more by the viewing angle than by the slope of the external density profile. Steeper density profiles are found to produce more gradual jet breaks while larger viewing angles cause smoother and later appearing jet breaks. The counter-jet becomes visible as it becomes sub-relativistic, and for k=0 this results in a clear bump-like feature in the light curve. However, for larger k values the jet decelerates more gradually, causing only a mild flattening in the radio light curve that might be hard to discern when k=2. Late time radio calorimetry is likely to consistently over-estimate the true energy by up to a factor of a few for k=2, and either over-predict or under-predict it by a smaller factor for k = 0,1.Comment: 10 pages, 13 figures, submitted to Ap

Quantitative Trait Loci (QTL) for Salt Tolerance in Soybean and Physiological Response to Salt Stress During Early Growth Stage

Soybean is a major cash crop used as a source of high–quality protein and oil. Salt stress is one of the main abiotic stresses causing significant yield losses in soybean, which is considered a moderately salt–sensitive crop. Breeding selection is a promising strategy to improve salt tolerance as soybean germplasm display wide variation in response to salinity stress. However, the physiological and genetic mechanisms for salt tolerance are not quite clear. The discovery of novel QTL/genes associated with salt tolerance facilitates the development of tolerant cultivars through marker-assisted selection (MAS). The objectives of this study were: 1) identify/confirm QTL associated with salt tolerance, and 2) evaluate progressive shoot ion accumulation in sensitive/tolerant genotypes and leaf physiological changes induced by salt stress during early growth stage. For the first objective, QTL mapping was performed using an F2:3 population from Jake (tolerant) x Ozark (sensitive). A major QTL was found on chromosome 3 linked to four SNP loci in the same genomic region previously reported, explaining 37% to 49% of the phenotypic variation in LSS, PDP, leaf chlorophyll and leaf chloride content. Additionally, a new minor QTL linked with two SNP markers was identified on chromosome 19 explaining 5% of leaf chlorophyll variation. These QTL and linked SNP markers will be useful in MAS for salt tolerance. For the second objective, two sensitive (Desha, Ozark) and two tolerant (Jake, Lee) cultivars were treated with NaCl and KCl at 80 mM and 120 mM from stage V1 to V5. The most adverse effects on tolerant and susceptible varieties, was caused by KCl compared to NaCl stress. Under KCl treatment, the tolerance capacity of the excluders was severely inhibited causing early death, while under NaCl stress, tolerant varieties were able to accumulate up to 2.3 and 3.8 times less leaf Cl- and leaf Na+, respectively, than the sensitive ones. Plant death occurred when shoot ion concentration reached 80,000 mg/kg and 18,000 mg/kg of Cl- and Na+, respectively, under 120 mM NaCl. Under 120 mM KCl, plants died when leaf Cl- content reached 120,000 mg/kg and leaf K+ content was over 100,000 mg/kg