Complete breakdown of the Debye model of rotational relaxation near the isotropic-nematic phase boundary: Effects of intermolecular correlations in orientational dynamics

The Debye-Stokes-Einstein (DSE) model of rotational diffusion predicts that the rotational correlation times $\tau_{l}$ vary as $[l(l+1)]^{-1}$, where $l$ is the rank of the orientational correlation function (given in terms of the Legendre polynomial of rank $l$). One often finds significant deviation from this prediction, in either direction. In supercooled molecular liquids where the ratio $\tau_{1}/\tau_{2}$ falls considerably below three (the Debye limit), one usually invokes a jump diffusion model to explain the approach of the ratio $\tau_{1}/\tau_{2}$ to unity. Here we show in a computer simulation study of a standard model system for thermotropic liquid crystals that this ratio becomes much less than unity as the isotropic-nematic phase boundary is approached from the isotropic side. Simultaneously, the ratio $\tau_2/\eta$ (where $\eta$ is the shear viscosity of the liquid) becomes {\it much larger} than hydrodynamic value near the I-N transition. We have also analyzed the break down of the Debye model of rotational diffusion in ratios of higher order rotational correlation times. We show that the break down of the DSE model is due to the growth of orientational pair correlation and provide a mode coupling theory analysis to explain the results.Comment: Submitted to Physical Review

Optimized 3D Segmentation Algorithm for Shelly Sand Images

There is much to be gained from analysing and studying calcareous sediment, with applications ranging from the study of climate change, rock dating, and even building offshore oil rigs and wind farms. One way of performing this analysis is to obtain a µCT scan of the sediment, allowing scientists and engineers to automate much of their analysis using software. Many existing and prospective analysis techniques require handling individual grains. Thus, fast and effective segmentation is an essential first step for any such analysis. Segmentation is non-trivial; these scans hold a lot of information, exhibit ambiguous boundaries between objects, and many objects are hollow, making it even more difficult to apply traditional watershed segmentation. Addressing these issues, in this paper we propose an optimized 3D segmentation (O3DS) algorithm based on watersheds. We make use of branch recursion, partition the image by height prior to segmentation, artificially reducing the size of the largest connected objects. These and additional changes are extremely effective in optimizing performance; O3DS reduces the time to segment a 659x925x932 scan of sediment by 95.4% and produces better or comparable results when compared to similar implementation by our co-author

Abnormalities of White Matter Microstructure in Unmedicated Obsessive-Compulsive Disorder and Changes after Medication

BACKGROUND: Abnormalities of myelin integrity have been reported in obsessive-compulsive disorder (OCD) using multi-parameter maps of diffusion tensor imaging (DTI). However, it was still unknown to what degree these abnormalities might be affected by pharmacological treatment. OBJECTIVE: To investigate whether the abnormalities of white matter microstructure including myelin integrity exist in OCD and whether they are affected by medication. METHODOLOGY AND PRINCIPAL FINDINGS: Parameter maps of DTI, including fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD), were acquired from 27 unmedicated OCD patients (including 13 drug-naïve individuals) and 23 healthy controls. Voxel-based analysis was then performed to detect regions with significant group difference. We compared the DTI-derived parameters of 15 patients before and after 12-week Selective Serotonin Reuptake Inhibitor (SSRI) therapies. Significant differences of DTI-derived parameters were observed between OCD and healthy groups in multiple structures, mainly within the fronto-striato-thalamo-cortical loop. An increased RD in combination with no change in AD among OCD patients was found in the left medial superior frontal gyrus, temporo-parietal lobe, occipital lobe, striatum, insula and right midbrain. There was no statistical difference in DTI-derived parameters between drug-naive and previously medicated OCD patients. After being medicated, OCD patients showed a reduction in RD of the left striatum and right midbrain, and in MD of the right midbrain. CONCLUSION: Our preliminary findings suggest that abnormalities of white matter microstructure, particularly in terms of myelin integrity, are primarily located within the fronto-striato-thalamo-cortical circuit of individuals with OCD. Some abnormalities may be partly reversed by SSRI treatment

Evaluation of the sound emissions and climate acoustic in proximity of one railway station

In Europe, the acceptance of the railways as a driving force for the development economic and ecological it is subject at the rail noise reduction, aspect important for people's health and the environment. The acceptance of the noise for the citizens, living in the vicinity of railway lines, is of vital importance in view of the increasing number of trains and consequently of the noise they produce. Therefore, measures to reduce the noise levels are essential to prevent health risks in the citizens exposed. Health effects due to prolonged exposure to environmental noise, rarely can cause directly damage to hearing (hearing loss). Many damages psychosomatic, can affect the apparatus: digestive, respiratory, visual, reproductive, skin and circulatory systems and blood. Precisely for these reasons, in recent decades the actions of assessment and reduction of noise, coming from the civil engineering infrastructure, have become of paramount importance and cannot longer be neglected. The aim of this study is the evaluation of noise emission coming from a railway yard inserted in an urban context, and the acoustic environment in the surrounding area and the possible presence of sources concomitants in the railway area. The work presented here is part of a larger project aimed at developing a 3-D numerical model of the survey area, to be used for the noise-mapping of the area in the existing situation, both for the simulation of future order, resulting after the inclusion of noise abatement systems aimed at reducing noise pollution

Reducing the demand of energy cooling in the CED, "centers of Processing Data", with use of free-cooling systems

The data processing centers (CED) are defined today among the areas with the greatest demand for energy for specific use, and for the intrinsic operation of the technological equipment of processing and the data transmission. As a result of the high diffusion of today's telecommunications systems, the CEDs are increasingly widely disseminated and characterized by logics of operation, such as to ensure a high level of reliability in terms of continuity of service. Objective of the proposed study is to evaluate the reduction of demand energy by cooling, through implementation of air conditioning technologies based on air-conditioning systems of free-cooling type. The study compares different operating scenarios in relation to hypothetical operating conditions, in different regions of Italy characterized by different environmental thermo-hygrometric conditions, highlighting the limiting factors in terms of energy demand

Hypothermia Risk, Monitoring and Environment Control in Operating Rooms

The air-conditioning systems in operating rooms must be able to ensure at the patients at the surgical team a high level of comfort indoor. There is many factors to consider and analyze in order to prevent the occurrence of problems such as hypothermia of the patient, the thermal discomfort for the medical team, and not least, pollution by anesthetic gases. The thermal comfort conditions within the operating rooms can be obtained by controlling microclimatic parameters such as: temperature, relative humidity and air velocity. In an environment maintained in the condition of health and thermal comfort are minimized risks related to the onset of post-operative complications. In this paper we present some studies reported in the literature on the methods used for environmental monitoring and control of operating rooms and HVAC systems; they are treated in the methodologies actually used to obtain a hospital environment in conditions of healthiness and thermal comfort. Are reported the result some simulations, obtained with the use of a model of the operating room in real scale, in them are analyzed ventilation rates suitable to obtain the chemical dilution of anesthetic gases and contaminants physical-biological. In the simulations we have determined the microclimatic parameters (air humidity and temperature) for prevent risks for patients such as hypothermia, and to ensure the comfort of the surgical team

Analysis of air pollution in the urban center of four cities sicilian

The process of urbanization in this new millennium is characterized by the fact that more than three quarters of Europe's population is concentrated in urban areas, thus it becomes essential the issue of how to reconcile the development of our cities with the respect and protection of the environment. Polluting vehicle emissions constitute a major contribution to the deterioration of urban air quality and represent a potential risk to public health of citizens. The qualitative improvement of processes of production it is to be considered in the near future, a priority for urban pollution reduction and for improving the quality of life of our cities. This paper shows the air pollution analysis of the urban center of four Sicilian city, and the concentrations of the critical pollutants (PM10â\u88\u97NO2â\u88\u97SOâ\u88\u97O3â\u88\u97COâ\u88\u97C6H6â\u88\u97NH3â\u88\u97COVNM.). Linear regressions were performed to represent the relationships between the main pollutants; they were analyzed also the differences between the concentrations of pollutants, and their progress over the years

Technical and economic evaluations about the integration of co-Trigeneration systems in the dairy industry

The dairy industries are characterized by a high demand for electricity, and energy for heating and cooling, necessary for obtaining a finished quality product. The scope of this study is to evaluate the technical and economic feasibility of a proposed intervention in the integration of a cogeneration and trigeneration system fueled with natural gas in an existing factory service, located in the north of Italy. The proposed intervention is analyzed in order to allow for the reduction of the overall energy demand of primary energy optimizing the activity management cost. The energy demand of this activity is analyzed below. The design choice are made in terms of energy production and distribution, as well as the economic and financial assessments related to the energy integration of either the cogeneration system or by tri-generation

Evaluation on the convenience of a citizen service district heating for residential use. A new scenario introduced by high efficiency energy systems

The target of the study is to assess, in the light of today's energy production technologies with high efficiency, the actual energetic advantage, in terms of environmental and economic sustainability, of traditional district heating systems for residential use. It was examined a real case study consisting of a residential complex in Milan served by the district heating system of the city. The study was conducted by comparing costs for heating and hot water supplied by district heating with those of alternative potential systems for energy production present on the market today. Two proposals for the replacement of the district heating system with high efficiency heat generators or with heat pumps were evaluated.Therefore, was carried out an evaluation of technical and economic feasibility with particular reference to the payback period, considering interruption of district heating services currently ongoing. (Presented at the AIGE Conference 2015)