Properties Of Vacuum Research Articles

Estimation of thermophysical propreties of far infrared vacuum drying potato by application of inverse approach

In this paper the estimation of the moisture diffusivity, together with other thermophysical properties of a far-infrared vacuum dried potato slices by using an inverse approach were studied. In direct problem a mathematical model of the far-infrared vacuum drying process of shrinking bodies was used. The Leven-berg-Marquardt method was used to solve the inverse problem. An analysis of the influence of the vacuum pressure, temperature of heaters, drying body dimension, and drying time, that enables the design of the proper experiments by using the so-called D-optimum criterion was conducted. The estimated values of moisture diffusivity of potato obtained from this study are within the range from 5.14?10?8 to 5.01?10?9 m2/s. The experimental transient temperature and moisture content changes during the far infrared vacuum drying were compared with numerical calculated values.

Photon scattering by a 4π -spherically-focused ultrastrong electromagnetic wave

Author(s): Jeong, TM; Bulanov, SV; Sasorov, PV; Korn, G; Koga, JK; Bulanov, SS | Abstract: The scattering of high-power probe laser pulses by tightly focused ultrastrong laser pulses has been investigated through a semiclassical approach using a perturbative method based on the Born approximation. Under a 4π-spherically-focused ultrastrong light field, the electric permittivity and magnetic permeability tensors for vacuum are calculated from the Euler-Heisenberg Lagrangian to show the nonlinear birefringent property of vacuum. And, from permittivity and permeability tensors, the scattering potential is derived for the Born approximation. The first-order solution of the Born approximation is taken as an electric field scattered from the 4π-spherically-focused laser pulse when a probe laser pulse propagates through the focused laser field. The differential cross section of the nonlinear birefringent vacuum is derived, and the number of photons scattered from the nonlinear birefringent vacuum is analyzed in the laser power range of 10-1000 PW.

Structural and optical properties of Fe-doped TiO2 films by sol–gel method

Fe-doped TiO2 films were prepared by sol–gel spin coating method. After annealing in vacuum, the structural and optical properties of the films were investigated. XRD patterns revealed that all diffraction peaks can be attributed to TiO2 with anatase phase structure. No segregated phases are present in the samples within XRD detection limit. XPS results indicated that iron element exists in a tervalent state and incorporates into TiO2 lattice. Raman spectra demonstrated that all the films are in pure anatase phase. No other vibration modes in the spectra were detected. Raman spectra are consistent with the results of XRD patterns. Photoluminescence spectra at room temperature are sensitive to the concentration of Fe doping. The quenching increases with the increase in amount of dopant, which can be due to the introduction of defect sites such as oxygen vacancy by Fe doping. The free hole can interact with a trapped electron, or a free electron can interact with a trapped hole, resulting in non-radiative.

The development of architectural technology and Impact on the interior design of interactive spaces

This paper discusses the effect of technology development, such as the emergence of interactive architecture) as the direction of the trends of modern architecture and its impact on the formation of interactive intelligent space, and the decisive factors of reaction and reaction. With the human interior space, the rhythm of science and technology, the impact of this era's interior architecture, and the designer's who install installation elements and interrelations based on methods and theories Technology, Finally design the shape related to function.Although the interior design creates the internal environment to meet individual requirements, but the human sense of the kind of failure to comply with this design over time produces a sense of monotonous and bore as well as , the emergence of modern technology and the change of building envelope lead to the change of the vacuum property inside the building, so as to recognize and respond to the nature. This is a trend of design Packaging or internal space respond to each other or adapt to human inhabitant of space . With the emergence of direction Interior Design Interactive Interior Design found a link through the response Sensory determinants vacuum internal, showed the surfaces of self-cleaning and walls invisible Structures of self-reproduction, This technique has created a whole generation of smart materials, It has strength and light weight and also this technique in turn creates an internal vacuum for wireless These smart materials are a material change to respond to the surrounding environment became Some materials contain Nano computers that can send signals or paint, anti-microbial, Modern technology materials keeps up with the trend of modern architecture. Through the application of modern trend in interior design, we find that this is a huge revolution In the field of interior design through smart materials developed applications working to respond to the interior space user This trend on the use of technology on an integrated social level in the design explores the humanitarian needs within the context of responsive technologies.

Thermal desorption of cryopumped gases from laser treated copper

Recently, laser processing of copper samples has been demonstrated to produce rough surfaces whose nanostructuring ensures unquestionable advantages for electron cloud mitigation in future particle accelerators. The actual application of laser treated surfaces in accelerators implies that this new material is compliant with many issues, going from impedance vacuum properties to many others. A significant experimental effort is therefore ongoing to study and optimize their various properties of interest. Here we analyze their vacuum behavior versus temperature. To this end, we studied thermal programmed desorption from CO, ${\mathrm{CH}}_{4}$ and ${\mathrm{H}}_{2}$ once cryosorbed on laser treated copper substrate and on its flat counterpart. These molecules are typically present in the residual vacuum of any accelerator. The results show that the desorption of such gases from the laser treated substrates occurs in a much broader and higher temperature range with respect to what is observed from the flat substrate. We also show that, at equal doses, treated samples adsorb/desorb significantly more gas than their flat counterpart. These findings can be ascribed to their nanostructured porous morphology. A quantitative analysis is given, allowing to properly estimate fluctuations of the number of molecules during unavoidable temperature variations of the cryogenic vacuum system.

Comparison of Structural, Electrical and Thermoelectric Properties of Vacuum Evaporated SnTe Films of Varied Thickness.

As a key type of promising thermoelectric (TE) material p-type Tin Telluride (SnTe) vacuum evaporated thin films synthesized at room temperature (RT) on a glass substrate, report a significant enhancement in the figure of merit (ZT) value. The thicknesses of the nanostructured thin films were kept about 145 nm and 275 nm. High-resolution X-ray diffraction (HRXRD) outlines the polycrystalline nature in both thin films. Surface morphology of these films is composed of grains of variable sizes as elucidated by scanning electron microscopy (SEM). This observation is further confirmed by atomic force microscopy (AFM) wherein the average roughness, surface skewness, and surface kurtosis parameters are used to analyze the surface morphology. Local microstructural features and crystalline structure have been confirmed from High-resolution transmission electron microscope (HRTEM) and the selected area electron diffraction (SAED) pattern, respectively. Four probes method was used to determine electrical measurements which confirm that the thin films have semi-metallic nature. Thermoelectric measurements carried out on these films resulted that the figure of merit increases as the thickness of the film increases. The maximum ZT value of ˜1.02 is obtained at room temperature for the thin film of thickness 275 nm.

Effect of different surface pretreatment method on vacuum brazing joint properties of AlSi50 alloy

In this paper, the effect of different surface pretreatment method on properties of vacuum brazed joint of AlSi50 alloy was investigated. The surface pretreatment methods of specimen before brazing include sanding, NaOH corrosion, HCl corrosion, H2SO4 corrosion and nickel plating. The experimental results indicate that the width of brazing joint varies with different surface pretreatment methods. The joint with sanding pretreatment, has the largest brazing seam width of 20 μm. Meanwhile, joint with H2SO4 corrosion has the narrowest brazing seam width. The brazing filler metal can wet and spread on different pretreated specimen very well. Spectrum analysis indicates that nickel-plate on AlSi50 surface, can interact with brazing filler metal, which increases mechanical property of brazing joint. For brazing of AlSi50 alloy, the optimal pretreatment method is nickel plating. After nickel plating pretreatment, brazing joint has the maximum shear strength 82.05 MPa by using brazing filler metal Al52-Cu33-Mg12-Ni3 and following technological parameters: brazing temperature 580 ℃, soaking time 30 min and pressure 3 MPa.

We need to rethink lower-division physics teaching

We need to rethink lower-division physics teaching

The antioxygen radiation properties of the nanocomposite film consisted of hydrogenated amorphous carbon (a‐C:H) and MoS2

MoS2/a‐C:H multilayer film and MoS2/a‐C:H composite film exhibit excellent tribological properties in vacuum, which can be used as the potential space lubricant. The radiation‐protective properties of these two films in atomic oxygen (AO) are evaluated. The influences of AO radiation on structure, morphology, and tribological properties of the films were investigated. The results show that AO radiation mainly causes oxidation and increases sp2 C content in both of the films. Furthermore, the MoS2 sublayer on the surface of the multilayer film is oxidized heavily, whereas both the MoS2 and the a‐C:H matrix on the surface were oxidized in the composite film. As a result of this, the multilayer film exhibits high friction coefficient and short sliding lifetime in vacuum after AO radiation. Compared with that, the composite film exhibits lower friction and longer sliding time more than 3600 seconds in vacuum, which illustrates it has a good AO radiation protection. This indicates that MoS2/a‐C:H composite film is more likely to be used as a potential space lubricant.

Suitability of graphene monolayer as sensor for carcinogenic heavy metals in water: A DFT investigation

The present article discusses the sensing ability of graphene monolayer for the possible detection of carcinogenic heavy metals like Arsenic (As), Cadmium (Cd), Chromium (Cr), Mercury (Hg) and Lead (Pb)) present in water as pollutants and responsible for various health diseases. Density functional theory based first principle approach has been used to understand the sensing behavior of graphene monolayer by analyzing it’s electronic and transport properties both in vacuum and aqueous environment. The investigations have revealed that the pure graphene has no sensitivity towards water molecule, however interacts well with the carcinogenic heavy metal Cr with significant charge transfer, calculated through Bader Analysis. The significant variations in the band structure, density of states (DOS) profile and current–voltage characteristics of graphene monolayer due to presence of Cr, confirms that the graphene monolayer is relatively better candidate for the detection of Cr at small applied voltage of 400 mV in water, with a response of 82%, in comparison to the other heavy metals, reported in the present work.

Theoretical and Experimental Study of a New Imidazo (1,2-a) Pyridine Derivative as a Corrosion Inhibitor for the Carbon Steel Surface in the Saline Media

Newly synthesis derivative of imidazo (1,2-a) pyridine namely, 2-(4-Bromo-phenyl)-2,3-dihydro-imidazo[1,2-a] pyridine-3-yl methylene]- phenyl-amine (BDIPMA) was investigated as corrosion inhibitor for carbon steel in saline solution (3.5% NaCl) using potentiometric polarization measurements. Experimentally, the thermodynamic parameters obtained have supported a physical adsorption mechanism and the adsorption followed the Langmuir adsorption isotherm. Quantum mechanical method of the Density Functional Theory (DFT) of B3LYP with [6-311++G (2d, 2p)] level were used to calculate the optimized structure, chemical inhibition efficiency parameter (%IE) and physical properties in vacuum and two solvents (DMSO and H2O), all at the equilibrium geometry. The surface changes of the carbon steel were studied using SEM and AFM techniques.

Types of overvoltages in 10-35 kV distribution networks and modern methods and means of their limitation

The basis for the transmission of electrical energy from sources to receivers are overhead power lines 10-35 kV. In these networks, an isolated transmission line or transmission line, grounded through resistors or using arc-quenching reactors, is used. The Republic of Mari El uses networks with isolated transmission line, the total length of which is more than 7000 km. When operating distribution networks, their insulation is affected by a number of internal factors such as long-term operating voltage and voltage fluctuations, short-term overvoltages associated with arc closures, wire breaks, and insulation overlaps. These networks are located on an open area, so they are exposed to lightning overvoltages, temperature, wind loads (mechanical forces), precipitation (snow, humidity). Overvoltages occurring in electrical systems are one of the main factors that significantly affect the reliability of power supply. Despite the short-term effects, overvoltages are characterized by a high multiplicity with respect to the long-term operating voltage, the impact on all electrically connected elements of the system, regardless of the place of occurrence. Overvoltage is the main cause of defects and accelerated aging of structural components. Currently, 90 % of 10-35 kV overhead lines are made on the basis of the use of reinforced concrete structures of supports that require grounding devices, depending on the value of the soil resistivity. Highspeed vacuum circuit breakers are used as switching devices in modern distribution networks of 10-35 kV. The specific properties of vacuum as an arc-quenching medium contribute to the transients in their switching, which require scientific understanding.

Absolute zero in Casimir vacuum

Casimir vacuum has many peculiar properties, e.g. the speed of light can exceed c. This paper investigated the behavior of gas molecules in Casimir vacuum. Analysis and calculation indicate that we can get a new absolute zero in Casimir vacuum. This is due to the Hamiltonian, which equals the kinetic energy of the ensemble of gas molecules that is reduced in Casimir vacuum; therefore, the gas constant R is changed. This conclusion has great significance for the research of the vacuum properties.

Physicochemical properties of vacuum packaged snake fruits in the presence of olive leave extract

This research was done to investigate the effectiveness of the presence of olive leaf extract in vacuum packaging in maintaining the physicochemical properties of fresh-cut snake fruit under ambient temperature. The snake fruits were vacuum packaged in the presence of 3% (v/w) olive leave extract (OLE) and stored in room temperature for 8 days of storage. The physicochemical properties including color changes, firmness, and total dissolved solid (TDS) were observed. The results indicated that addition olive leaves extract in vacuum packaging gave the best result by inhibiting color changes by declining in total color difference by 10.88, BI 5.08, absorbance 2.750 Ǻ declining in hardness by 14.61% and lowest TDS level. As an alternative method of storing fresh-cut snake fruit under ambient conditions, vacuum packaging containing olive leave extract can be used.

A review of Higgs boson pair production

Abstract In 2012 the ATLAS and CMS collaborations discovered at the LHC the Higgs boson decaying to vector bosons. This discovery has provided a strong indication that the mechanism of Electroweak Symmetry Breaking (EWSB) is similar to the one predicted by Brout-Englert-Higgs (BEH) nearly 50 years before. Since then, one of the priorities of the LHC program, as well as of the majority of the future collider proposals, is to measure directly the parameters of the EWSB potential. The goal is to identify if it has indeed the straightforward quartic shape predicted by BEH or it is more complex, as the result of an unexplored physics nature. The answer to this major scientific question will have a considerable impact on our understanding of vacuum properties and the history of the universe through the EWSB during the Big Bang. The only direct way to probe these couplings is through the measure of the production of multiple Higgs bosons, two being the simplest case. In this paper, we present a comprehensive review of the current searches and the state of the art insights on the topic. In particular, we explain why this ambitious project is even more challenging than the discovery of the Higgs boson itself. Finally, we sketch the plans of the HEP community for how to access the parameters of the BEH mechanism. This review is adapted to a curious reader familiar with particle physics in general or a scientist who wants to have a landscape overview of the topic.

Silver particulate films on softened polymer substrates pre-coated with selenium

The formation of subsurface particulate films when certain inorganic materials are vacuum deposited on softened polymer substrates is known for long. The subsurface structure formation is dependent on thermodynamic as well as deposition conditions. The subsurface particulate structure is similar to the discontinuous films under the polymer cover. The discontinuous films do exhibit certain interesting properties and the exploitation of these properties is constrained by the instabilities in their properties in vacuum as well as the degradation in atmosphere. The subsurface particulate structures are believed to be a solution against the instabilities of discontinuous films. Further, the morphology of the subsurface particulate structures is strongly dependent on the nature of the polymer and the polymer metal interaction. While interacting polymers like poly(2-vinylpyridine) (P2VP) and poly(4-vinylpyridine) (P4VP) suffer from the hygroscopic nature, inert polymers like polystyrene (PS) do not facilitate organised structure with small particles and small separations. The modifications of an inert polymer like PS by blending with an interacting polymer like P4VP, by electron beam irradiation to create free radicals, by doping with surfactants like 3-mercaptopropyltrimethoxysilane (MPTMS), by creating pre-nucleation centres with selenium have been carried out. The silver particulate films on such modified softened polystyrene substrates show interesting optical, structural and electrical properties. Some of these results are discussed in the article.

Chiral symmetries in nuclear physics

In this report the theoretical concepts of a chirally symmetric meson field theory are reviewed and an overview of the most relevant applications in nuclear physics is given. This includes a unified description of the vacuum properties of hadrons, finite nuclei and hot, dense and strange nuclear matter in an extended chiral SU(3)_L x SU(3)_R σ-ω model.

Microstructural evolution and mechanical properties of FeNi42 alloy and SiC ceramic joint vacuum brazed with Ag-based filler metals

FeNi42 alloy and SiC ceramic were successfully brazed with active Ag-27.3Cu-2.5Ti wt.%, Ag-26.8Cu-4.5Ti wt.% and inactive Ag–Cu eutectic filler metals. The effect of Ti content and brazing temperature on the microstructure and mechanical properties of the brazed joints was studied. For the microstructure of joints brazed with Ag-27.3Cu-2.5Ti wt.% and Ag–Cu eutectic filler at 920 °C, the dissolved Fe and Ni elements in the liquid filler would react with SiC, causing the excessive dissolution of the ceramic, and the shear strength of joints was less than 30 MPa. By increasing the Ti content or reducing the brazing temperature, the SiC dissolution was greatly inhibited, and the maximum joint shear strength reached 60 MPa when the joint was brazed with Ag-27.3Cu-2.5Ti wt.% at 880 °C. To reveal the reaction mechanism and microstructural evolution of brazed joints, the brazing of pure metals of Fe and Ni with SiC ceramic was carried out. Consequently, the three-stage reaction process of SiC ceramic in FeNi42/Ag–Cu–Ti/SiC joint was proposed, and Ni was found to be the dominated element for the dissolution of SiC ceramic during brazing.

Optically levitated microsphere can act as a non-ionizing pressure gauge

The relationship between a dielectric particle’s dynamics and the gas pressure surrounding it determines vacuum properties.

ФРИКЦИОННЫЕ СВОЙСТВА ПОЛИМЕРОВ ДЛЯ 3D-ПЕЧАТИ ПРИ ТРЕНИИ В ВАКУУМЕ

ФРИКЦИОННЫЕ СВОЙСТВА ПОЛИМЕРОВ ДЛЯ 3D-ПЕЧАТИ ПРИ ТРЕНИИ В ВАКУУМЕ