Vibrational excitons, resonant energy transfer, and local structure in liquid benzene

The presence of vibrational excitons in liquid benzene has been tested by the method of isotopic dilution. A C6H6/C6D6 concentration study on the infrared and Raman fundamental modes reveals that the umbrella (A2u) vibrational exciton in solid benzene retains its characteristics upon melting and at room temperature. The total liquid exciton bandwidth is about 40 cm−1, practically the same as in the solid. This indicates an instantaneous local liquid structure similar to that of the solid (the Ci crystal site symmetry is also nearly preserved), in general agreement with indications from other methods. The fastest nearest neighbor vibrational resonant transfer takes about 1 psec. The residual linewidth at isotopic dilution is 3–4 cm−1, which is due to inhomogeneous and/or homogeneous broadening. The respective overall reorientational and/or translational relaxation takes about 2 psec or longer. The exciton linewidth is proportional to the square root of the isotopic concentration except for a sudden break at some critical concentration.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70052/2/JCPSA6-66-11-5035-1.pd

Erratum: Thermodynamics of solid and liquid EAM metals: A variational study [J. Chem. Phys. 94, 5090 (1991)]

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70785/2/JCPSA6-95-8-6197-1.pd

GAMBARAN PENGETAHUAN DAN TINDAKAN MASYARAKAT TENTANG PENGENDALIAN VEKTOR DEMAM BERDARAH DENGUE DI DESA TOUURE KABUPATEN MINAHASA TAHUN 2020

Demam Berdarah Dengue (DBD) adalah salah satu penyakit menular yang dapat dan sering menimbulkan wabah yang tidak jarang menyebabkan kematian. Berdasarkan data kasus DBD di tahun 2017 kasus DBD yang ada di wilayah kerja Puskesmas Tompaso berjumlah 9 kasus, pada tahun 2018 terdapat 8 kasus DBD di wilayah kerja Puskesmas Tompaso, sedangkan di tahun 2019 sebanyak 36 kasus yang berada di wilayah kerja Puskesmas Tompaso dan 18 kasus (50% dari total kasus) berasal dari Desa Touure Kecamatan Tompaso Kabupaten Minahasa. Masih tingginya angka kesakitan dan kematian DBD salah satu faktornya adalah kurangnya pengetahuan masyarakat tentand DBD dan tindakan masyarakat yang kurang baik dalam pengendalian vektor DBD berpotensi menjadi factor risiko penularan penyakit DBD. Tujuan penelitian adalah untuk mengetahui gambaran pengetahuan dan tindakan masyarakat tentang pengendalian vektor DBD di desa Touure kecamatan Tompaso tahun 2020. Jenis penelitian yang digunakan yaitu penelitian survei deskriptif. Sampel penelitian adalah masyarakat desa Touure kecamatan Tompaso sebanyak 70 masyarakat. Analisis data dilakukan secara deskriptif berdasarkan distribusi frekwensi. Instrumen yang digunakan dalam penelitian berupa kuesioner selain itu, penelitian ini menggunakan alat tulis menulis, komputer/ laptop dan kamera. Data yang diperoleh ditampilkan menggunakan tabel. Hasil penelitian menunjukkan bahwa pengetahuan responden paling banyak terdistribusi pada kategori tidak baik (78,6%), menunjukkan bahwa tindakan responden paling banyak terdistribusi pada kategori tidak baik (70%).         Kata Kunci :Demam Berdarah Dengue, Pengetahuan masyarakat, Tindakan masyarakat ABSTRACTDengue Hemorrhagic Fever (DHF) is a contagious disease that can and often causes epidemics that often cause death. Based on data on dengue cases in 2017 there were 9 cases of dengue fever in the Tompaso Puskesmas work area, in 2018 there were 8 cases of dengue in the Tompaso Puskesmas work area, while in 2019 there were 36 cases in the Tompaso Puskesmas work area and 18 cases (50% of the total cases) came from Touure Village, Tompaso District, Minahasa Regency. The high rate of DHF morbidity and mortality is one of the factors is the lack of public knowledge about DHF and poor community action in controlling the DHF vector which is a risk factor for DHF transmission. The research objective was to describe the knowledge and actions of the community about dengue fever in the village of Touure, Tompaso District in 2020. The type of research used was descriptive survey research. The research sample was 70 people in Touure village, Tompaso district. Data analysis was carried out descriptively based on frequency distribution. The instrument used in the research was a questionnaire in addition to that, research using written stationery, computers / laptops and cameras. Data that can be used using tables. The results showed that the respondents' knowledge was mostly distributed in the bad category (78.6%), indicating that the respondent's actions were mostly distributed in the bad category (70%). Keywords : Dengue Hemorrhagic Fever, Community Knowledge, Community Actio

A fully coupled 2D model of equiaxed eutectic solidification

We propose a model of equiaxed eutectic solidification that couples the macroscopic level of heat diffusion with the microscopic level of nucleation and growth of the eutectic grains. The heat equation with the source term corresponding to the latent heat release due to solidification is calculated numerically by means of an implicit finite difference method. In the time stepping scheme, the evolution of solid fraction is deduced from a stochastic model of nucleation and growth which uses the local temperature (interpolated from the FDM mesh) to determine the local grain density and the local growth rate. The solid-liquid interface of each grain is tracked by using a subdivision of each grain perimeter in a large number of sectors. The state of each sector (i.e. whether it is still in contact with the liquid or already captured by an other grain) and the increase of radius of each grain during one time step allows one to compute the increase of solid fraction. As for deterministic models, the results of the model are the evolution of temperature and of solid fraction at any point of the sample. Moreover the model provides a complete picture of the microstructure, thus not limiting the microstructural information to the average grain density but allowing one to compute any stereological value of interest. We apply the model to the solidification of gray cast iron

A new method for the simulation of alloys: Application to interfacial segregation

We present a new, accurate method for determining the properties of defects in alloys at finite temperature, including equilibrium segregation. This method is based upon a point approximation for the configurational entropy, an Einstein model for vibrational contributions to the free energy and may be employed with any type of description of atomic interactions. The atomic structure, segregation and thermodynamics of a defect in an alloy is determined by minimizing the free energy with respect to atomic coordinates and composition of each site at constant chemical potential. In order to test the accuracy of this approach, we compare our results with accurate Monte Carlo determinations. Overall, very good agreement for segregation to free surfaces and grain boundaries in Cu---Ni alloys is obtained. One of the main advantages this new method enjoys over other methods such as Monte Carlo, is the efficiency with which the atomic structure of a defect, segregation and thermodynamic properties can be determined. This efficiency is obtained in the framework of a very straightforward method and with little loss in accuracy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29021/1/0000051.pd

Coil optimization for electromagnetic levitation using a genetic like algorithm

he technique of electromagnetic levitation (EML) provides a means for thermally processing an electrically conductive specimen in a containerless manner. For the investigation of metallicliquids and related melting or freezing transformations, the elimination of substrate-induced nucleation affords access to much higher undercooling than otherwise attainable. With heating and levitation both arising from the currents induced by the coil, the performance of any EML system depends on controlling the balance between lifting forces and heating effects, as influenced by the levitation coil geometry. In this work, a genetic algorithm is developed and utilized to optimize the design of electromagnetic levitation coils. The optimization is targeted specifically to reduce the steady-state temperature of the stably levitated metallic specimen. Reductions in temperature of nominally 70 K relative to that obtained with the initial design are achieved through coil optimization, and the results are compared with experiments foraluminum. Additionally, the optimization method is shown to be robust, generating a small range of converged results from a variety of initial starting conditions. While our optimizationcriterion was set to achieve the lowest possible sample temperature, the method is general and can be used to optimize for other criteria as well

Influence of anisotropic vibrational motion on diffraction from grain boundaries

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28740/1/0000568.pd

Modeling of transformation toughening in brittle materials

Results from modeling of transformation toughening in brittle materials using a discrete micromechanical model are presented. The material is represented as a two-dimensional triangular array of nodes connected by elastic springs. Microstructural effects are included by varying the spring parameters for the bulk, grain boundaries, and transforming particles. Using the width of the damage zone and the effective compliance (after the initial creation of the damage zone) as measures of fracture toughness, we find that there is a strong dependence of toughness on the amount, size, and shape of the transforming particles, with the maximum toughness achieved with the higher amounts of larger particles.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29978/1/0000341.pd

Hydrogen atom in a spherical well: linear approximation

We discuss the boundary effects on a quantum system by examining the problem of a hydrogen atom in a spherical well. By using an approximation method which is linear in energy we calculate the boundary corrections to the ground-state energy and wave function. We obtain the asymptotic dependence of the ground-state energy on the radius of the well.Comment: Revised version to appear in European Journal of Physic