In this study a DFT calculation on cyclopropanone, cyclopropandione and cyclopropantrione molecules was performed using the basis function 6-31G ** / MP2 and exchange correlation potential B3-LYP. The results showed that the ground state of all molecules geometry belong to the point group 𝐶2𝑣where a vibronic coupling between the vibrational motion with the electronic ground state in the molecule C3O3 this leads to a reduction in symmetry of the molecule from𝐷3â„Žto 𝐶2𝑣, the driving force of this process is accessing to the electronic configuration complies with Hückel aromatic systems with two electrons. Also in this, study the normal modes of vibration, frequencies, intensities and symm

Abstract  

All central air conditioning systems contain piping system with various components, sizes, material, and layouts. If such systems in operating mode, the flow in piping system and its component such as valves can produce severe vibration due to some flow phenomenon’s. In this research, experimental measurements and numerical simulation are used to study the flow-induced vibration in valves. Computational fluid dynamics (CFD) concepts are included with one-way and two-way fluid-structure interaction concepts by using finite element software Package (ANSYS 14.57). Detection analysis is performed on flow characteristics under operation conditions and relations with structural vibration. Most of

We have theoretically investigated the in-plane lattice thermal conductivity of Zn4Sb3single quantum well structure taking into account spatial confinement of phonons. The calculations were carried out for free-surface quantum wells with thickness 8.5nm in the room temperature. We show that the lattice thermal conductivity is a significant reduce. The reduction is mostly due to the drop in the average group velocity caused by the spatial confinement of acoustic phonons and the corresponding increase in phonon relaxation rates. The predicted decrease is important for the anticipated applications of Zn4Sb3 nanostructure materials for room-temperature thermoelectric devices. Our theoretical results are in a good agreement with available exp

     In this paper, we consider a two-phase Stefan problem in one-dimensional space for parabolic heat equation with non-homogenous Dirichlet boundary condition. This problem contains a free boundary depending on time. Therefore, the shape of the problem is changing with time. To overcome this issue, we use a simple transformation to convert the free-boundary problem to a fixed-boundary problem. However, this transformation yields a complex and nonlinear parabolic equation. The resulting equation is solved by the finite difference method with Crank-Nicolson scheme which is unconditionally stable and second-order of accuracy in space and time. The numerical results show an excellent accuracy and stable solutions for tw

In the present study, synthesis of bis Schiff base [I, II] by reaction of one mole of terephthalaldehyde with two mole of 2-amino-5-mercapto-1,3,4-thiadiazole or 4-amino benzene thiol in the ethanol absolute, then compounds [I,II]  were reacted with Na₂CO₃ of distilled H₂O, then chloroacetic acid was added to yield compounds [III,IV]. O-chitosan derivatives [V,VI] were synthesized by reaction of chitosan with compounds [III,IV] in acidic media in distilled water according to the steps of Fischer. O–chitosan (grafted chitosan) [V,VI] was blended with synthetic polymer polyvinyl alcohol (PVA) to produce polymers [VII,VIII], then these polymers were blended with nano: Gold or Silver by u

Verbs are an important material in the construction of the sentence, as they are among the requirements of every sophisticated language, and in this regard, Ibn Al-Gothic (d. 367 AH): “Know that verbs are the origins of the buildings of most speech, and thus scholars called them buildings.” Verbs are the source of expression of the speakers’ ideas to represent the element of activity and movement, and with their knowledge We infer the meanings of Arabic words, and Ibn Al-Sarraj (d. 316 AH) defined it: “The verb denotes a meaning and a time, and that time is either past, present, or future.” Its letters are original and does not drop from its construction a letter in the conjugation of its conjugations, and it is in Arabic two type

     Dental amalgam is a mixture of approximately 50% mercury and varying ratios of silver, tin, zinc, and copper. Dental amalgam is a major source of mercury pollution because it is readily absorbed through 90-100% vapour and the oral mucosa. In addition, in certain situations with the oral environment, various types of metallic orthodontic brackets are highly aggressive and can lead to corrosion. However, polyvinyl alcohol (PVA) material has no cytogenetic effects on human health or the environment and is therefore applied in the manufacturing of the new composite material. Different additives from the bonding agent (PVA; 2.4, 4.8, and 7.2 g)  dissolved in about 10 ml of water, heated on a hot plate under a hig

  This paper is concerned with Double Stage Shrinkage Bayesian (DSSB) Estimator for lowering the mean squared error of classical estimator ˆ q for the scale parameter (q) of an exponential distribution in a region (R) around available prior knowledge (q0) about the actual value (q) as initial estimate as well as to reduce the cost of experimentations.         In situation where the experimentations are time consuming or very costly, a Double Stage procedure can be used to reduce the expected sample size needed to obtain the estimator. This estimator is shown to have smaller mean squared error for certain choice of the shrinkage weight factor y( ) and for acceptance region R. Expression for