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On the suitability of high vacuum electrospray deposition for the fabrication of molecular electronic devices

On the suitability of high vacuum electrospray deposition for the fabrication of molecular electronic devices

We present a series of three studies investigating the potential application of high vacuum electrospray deposition to construct molecular electronic de- vices. Through the use of time of flight secondary ion mass spectrometry we explore the use of this novel deposition technique to fabricating multilayer structures using materials that are compatible with the same solvents and films containing a mixture of molecules from orthogonal solvents. Using x- ray photoelectron spectroscopy we study the deposition of a polymer blend using electrospray and find evidence of preferential deposition of one of the components.
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Thermal Efficiency of a Concentrating Solar Collector Under High-Vacuum

Thermal Efficiency of a Concentrating Solar Collector Under High-Vacuum

Solar energy is one of the best candidates to produce process heat at mid temperatures to satisfy the industrial demand. The interest in improving solar thermal collector efficiencies is huge, in order to take full advantage from this source of energy. TVPSolar is a leading company in the field of high-performance solar energy conversion that develops and produces an innovative flat-plate solar thermal collector under high vacuum. Vacuum technology ensures that both gas convective and conductive losses are reduced to a negligible level, so that these flat-panels are able to reach high working temperatures (up to 200 °C) [1]. Concentrating Solar Power technology (CSP), combined with high vacuum insulation, could be an alternative to reach higher working temperatures. The sunlight concentration technology splits into two different broad categories: imaging and non-imaging concentration. As regarding Solar Thermal (ST) and photovoltaic (PV) applications, non-imaging concentration has been an interesting option, since mid-1960s [2]. CSP usually uses only direct-beam sunlight [3], so mirrors require high cleaning standards and tracking systems to efficiently harness solar energy in day-light hours, resulting in high maintenance costs and installation issues. Compound Parabolic Concentrator (CPC) is an example of non-imaging concentration of sunlight that could be designed for stationary or passive tracking thus having acceptable concentration ratio. Moreover, it can collect both direct-beam sunlight and part of diffuse light (only rays within the acceptance angle) [2] and concentrate them on an absorber tube. A new frontier in high efficiency solar collection could be a high vacuum flat solar panel, thick enough to be equipped with CPC. The CPC installed in a high vacuum envelope leads to various advantages: no need for mirror cleaning, no corrosion due to atmospheric agents, better insulation resulting in thermal loss reduction, possibility to deposit a IR reflective coating on the interior side of the glass to benefit from ‘photon recycling’ mechanism [4]. A pioneering work [5] has experimentally investigated the idea to place a CPC under vacuum to reach the high temperatures needed for methanol reforming but CPC dimensions and performances were limited by the small volume of the cylindrical vacuum chamber. To extend CPC sizes the vacuum chamber must increase too, so the surface under vacuum needs a mechanical support to sustain the glass against the atmospheric pressure and the CPC has to be designed to respect the support mechanical constraint.
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Ultra High Vacuum Physical Vapor Deposition of Yttrium Aluminate and Hafnium Aluminate High-k Dielectrics on Silicon

Ultra High Vacuum Physical Vapor Deposition of Yttrium Aluminate and Hafnium Aluminate High-k Dielectrics on Silicon

(<100Å). This may be due to the limitations of ellipsometry on accuracy and uncertainty of the calculated film parameters which stem from 1) the choice of starting assumptions during data analysis, i.e., there are different dispersion relations or dielectric functions for the dielectric film, none of which is taken to be the standard; and 2) the inevitable correlation of variables when extracting multiple variables in the very thin film regime [2]. This may also be from the uncertain composition of the aluminate films, and the presence of a silicate layer at the silicon and high-k interface. Since very thin films (20-50 Å) of high-k dielectrics are important to the CMOS industry, the ellipsometry must be combined with other methods for thickness measurement, such as transmission electron microscopy (TEM).
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Thermal Characteristics of Switched Reluctance Motor Under Different Working Conditions

Thermal Characteristics of Switched Reluctance Motor Under Different Working Conditions

In order to observe the temperature changing under high vacuum environment more intuitively and clearly, the winding variation curve under two working conditions is shown in Fig. 12. From the variation curve, it is found that the temperature of winding decreases with the increase of the emissivity, and the steady-state temperature time is about 150 minutes; the steady-state temperature time is reached after about 60 minutes, and the heat of radiating is small, so the time to reach the steady state is longer. Therefore, heat dissipation of SRM in a high vacuum environment is difficult, and measures must be taken to improve the temperature level of the winding insulation and materials. At the same time, cooling measures must be designed to increase the radiation dissipation.
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High-purity Platinum for Microelectronics42-46

High-purity Platinum for Microelectronics42-46

few high vapour pressure metals, the high vacuum required plays a major role in the purification process for most electron beam. floating zone operations[r]

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A high temperature vacuum extensometer

A high temperature vacuum extensometer

An autographic extensometer for use at temperatures up to l000°C is described. Strain information is obtained from within a high vacuum enclosure by a unique application of linear variable differential transformers which provides great versatility in strain magnification and range. Important details of the vacuum test chamber and extensometer are given. Typical high temperature stress- strain records for uranium and tantalum are included to illustrate the performance of the equipment.

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Annual Growth Rate Analysis of Select Private Sector Sugar Mills in Tamilnadu

Annual Growth Rate Analysis of Select Private Sector Sugar Mills in Tamilnadu

applications where a two-stage unit will not provide low enough suction pressure economically. Applicable range is from 26 mm Hg. abs. to 0.8 mm Hg. abs. but economics might dictate use of a Two-Stage Ejector at the upper part of the range and a Four-Stage Ejector at the lower end. Three-Stage Condensing Steam Jet Ejectors consist of a booster ejector, a booster condenser, and a Two-Stage Ejector consisting of a high-vacuum ejector, inter condenser, and low vacuum ejector. In some applications another condenser (after-condenser) can be used at the low vacuum ejector discharge.
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New Materials for Vacuum Chambers in High Energy Physics

New Materials for Vacuum Chambers in High Energy Physics

Vacuum chambers must fulfil ultra-high vacuum requirements while withstanding thermo-me- chanical loads. This is particularly true in high energy particle accelerator where interactions of particles with matter may induce thermal load, material activation, background … The choice of the material of the vacuum chamber is crucial for the final application. Metals such as stainless steel, copper and aluminium are usually used. Even with outstanding mechanical and physical properties, beryllium is used for very specific applications because of its cost and toxicity. Ceram- ics such as alumina are usually used for fast magnet vacuum chambers. With the next generation of high energy physics accelerator generation such as CLIC and TLEP, the problematic of high cy- clic thermal load induced by synchrotron radiation is raised. This paper aims at defining some figures of merit of different materials with respect to several load scenarios and presents briefly their vacuum compatibility.
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Process Parameter Optimization on H11 Steel in CNC Drilling Process through Coated and Uncoated Drill Bits

Process Parameter Optimization on H11 Steel in CNC Drilling Process through Coated and Uncoated Drill Bits

to establish the wear mechanisms of coated and uncoated tungsten carbide drills when drilling carbon fiber reinforced plastics (CFRP)/aluminum alloy (Al) stacks. During the drilling experiments, thrust forces were measured. For both coated and uncoated drills, abrasion was the dominant tool wear mechanism, affecting the entire cutting edges higher wear was observed on uncoated tools which caused a significant increase in thrust force during drilling both Al and CFRP materials. YOGENDRATYAGI [4] et al In this paper the drilling of mild steel with CNC drilling machine by using a tool high speed steel by applying Taguchi methodology. A L9 array, taguchi method and analysis of variance (ANOVA) are used to formulate the procedure tried on the change of parameter. Design offers a systematic method for optimization surface finish as well as high material removal rate (MRR). TURGAYKIVAK [5] et al this paper focuses on the optimization of drilling parameters using the Taguchi technique to obtain minimum surface roughness (Ra) and thrust force (Ff). A number of drilling experiments were conducted using the L16 orthogonal array on a CNC vertical machining centre. The experiments were performed on AISI 316 stainless steel blocks using uncoated and coated M35 HSS twist drills under dry cutting conditions. It was found that the cutting tool was the most significant factor on the surface roughness and that the feed rate was the most significant factor on the thrust forceA.I. FERNÁNDEZ-ABIA [6] et al analyzed the market of turning tools is coped majority by hard metal tools with CVD coating. However, availability of tools with sharp cutting edges is essential in light turning of small parts. In this context, PVD process is optimum for obtaining sharp edges. Therefore, a methodology is presented to evaluate the performance of PVD advanced tools for turning of difficult to machine materials. Four coatings were tested: AlTiSiN (nACo®), AlCrSiN (nACRo®), AlTiN and TiAlCrN. The analysis was developed carrying out wear tests and analyzing different signals such as cutting forces, EDX analysis of inserts, part roughness and insert image analysis. Results indicate that the best coatings for turning of difficult to machine materials as austenitic stainless steel sarenACo® and AlTiN coatings, since they offer the best performance.
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Energy Conservation Through Vacuum Coating & Metalizing Process – Case Study Sachin Jadhav, Dr. Santosh Dalvi

Energy Conservation Through Vacuum Coating & Metalizing Process – Case Study Sachin Jadhav, Dr. Santosh Dalvi

The evaporation system is the crucial part of any aluminium metallizer : high deposition rate and evaporation stability are instrumental to match-up with the high metallization speed. The ceramic evaporation boats needs to be powered and fed to deliver about 90% of the current maximum capacity standard. Design solutions for high evaporation boats are :

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Energy conversion between CO and porphyrins on surfaces studied by ultrafast vibrational and scanning tunneling spectroscopies

Energy conversion between CO and porphyrins on surfaces studied by ultrafast vibrational and scanning tunneling spectroscopies

First, the frequency-shift around time zero will be discussed as this is the relevant delay range for desorption. The redshift of the C-O stretch mode observed at long delay times is purely thermal and indicates a very small temperature increase (40 K), which is too low to cause desorption. In order to understand the desorption mechanism, we look at possible origins of the frequency blueshift: change of adsorption site or anharmonic coupling with low frequency vibrational modes. Firstly, the possibility of CO moving to another adsorption site is discussed as seen in the decarboxylation of CO-protein complexes 274,330-332 . A possible intermediate site of CO on the RuTPP/Cu(110) surface could be a Ru-N (imine) bridge site, as observed for CoTPP/Ag(111) by STM and DFT 305 . However such a bridge site occupation by CO has not been observed by STM imaging at 4.7 K. Moreover, occupying such a bridge site is expected to show a frequency redshift. CO on ruthenium surfaces also shows an intermediate state prior to desorption on a picosecond time scale 64 . This precursor state would have a weaker Ru-CO bond and could thus show a C-O blueshift 21 . However, during pump-probe measurements, a large fraction of molecules are not in the precursor state to desorption and are instead just adsorbed on a hot surface, so the redshift caused by coupling to the FT mode dominates. Using phase-sensitive detection, the influence of a blue shift could however be discerned for CO/Pt(111) 191 . The excitation of the CO-Ru external stretch mode by the high electron temperatures is a possible explanation for the observed blueshift, however, it is difficult to model in detail, due to a lack of information about the degree of coupling between the C-O stretch mode and the
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Joining Vacuum High Pressure Die Cast Aluminum Alloy A356 Subjected to Heat Treatment to Wrought Alloy 6061

Joining Vacuum High Pressure Die Cast Aluminum Alloy A356 Subjected to Heat Treatment to Wrought Alloy 6061

Currently, there are three major types of aluminum alloys, i.e., Al-Si-Cu, Al-Mg and Al-Si-Mg alloys used for die casting [3]. One of the most widely used conventional high pressure die casting(C-HPDC) aluminum alloys, named A356 is in the Al-Si-Mg group, which possesses excellent die castability, weldability, high ductility and strengths (UTS: 221 MPa, YS: 136 MPa) [4]. Meanwhile, wrought 6061 aluminum alloy has applied in this experiment, which is a precipitation hardening aluminium alloy, containing magnesium and silicon as its major alloying elements. It also has good weldability and strengths (UTS: 190 MPa, YS: 70 MPa) [5]. To improve the mechanical properties, such as UTS and YS, casting are often subjected to a T4, T5 and T6 heat treatment to achieve the required mechanical properties although the application of heat treatments adds extra costs to castings, particularly high for large castings and makes them less competitive despite of property enhancement.
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IOT based Parking Enforcement System

IOT based Parking Enforcement System

out air to create vacuum and then the suction cup sticks on the windshield and get locked .For unlocking the user has to dial the same OTP. Then the micro controller verifies that OTP from the previously dialled OTP .If they do not match then nothing will happen .If matched then the microcontroller produces logic’0’. The vacuum pump stops and then vacuum is released and the cups can be removed.

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Rotating quantum states

Rotating quantum states

Vilenkin’s quantisation is equivalent to the one suggested by Letaw and Pfautsch [1] for the scalar field, yielding a vacuum state equiv- alent to the Minkowski vacuum. In contrast, Iyer [6] argues that the modes which represent particles for a co-rotating observer have positive frequency with respect to the co-rotating Hamilto- nian, implying the following expression for the field operator:

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Nonlinear consolidation of vertical drains with coupled radial vertical flow considering time and depth dependent vacuum pressure

Nonlinear consolidation of vertical drains with coupled radial vertical flow considering time and depth dependent vacuum pressure

Abstract: The system of vacuum pressure combined with vertical drains to accelerate soil consolidation is one of the most effective ground improvement methods. The consolidation theories of soft soil improved by vertical drains including void-ratio- dependent compressibility and permeability have been widely applied in practice to predict the consolidation behavior. In this paper, analytical solutions of the consolidation of vertical drains are derived incorporating the loss and propagating stage of vacuum pressure. In addition, special solutions is obtained for the cases of instantaneous surcharge loading and staged surcharge loading, based on the general solution. The solution is verified by ignoring the propagating stage of vacuum pressure formation and comparing it with an existing solution. The effects of vacuum pressure loss and propagating stage combined with other parameters are investigated through the ratio between excess pore water pressure and surcharge loading.
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Shrinkage Effect of Vacuum Casting Process Parameters using Taguchi Method

Shrinkage Effect of Vacuum Casting Process Parameters using Taguchi Method

The analysis has implemented the combination of optimum parameter condition. Thus, the predicted value for shrinkage effect can be calculated. The factors such as resin temperature (30°C), mould temperature (60°C) and vacuum pressure time (5 min) are selected in the feature of ‘Predict Taguchi Result’. So, the predicted shrinkage value by using the optimize parameter condition is 0.159 mm as in Fig. 7.

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Vacuum Seed Sowing Manifold: a novel device for high-throughput sowing of Arabidopsis seeds

Vacuum Seed Sowing Manifold: a novel device for high-throughput sowing of Arabidopsis seeds

The seed sowing manifold increases the amount of seeds that can be sown by a researcher. This will allow researchers to design larger than previously possible ex- periments. The number of holes can be varied allowing sowing densities to be controlled according to the ex- perimental parameters or researcher preference. When combined with high throughput phenotyping platforms, it will allow a greater number of mutants and ecotypes to be investigated. It will also increase the amount of tis- sue (such as root tips) that researchers can harvest, mak- ing studies that require large amounts of tissue more viable (such as iTRAQ).
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Backreaction of Hawking Radiation on a Gravitationally Collapsing Star I Black Holes.pdf

Backreaction of Hawking Radiation on a Gravitationally Collapsing Star I Black Holes.pdf

Concerns with the first choice stem from the idealization of time symmetry, while concerns with the Unruh’s vac- uum arise from the question whether radiation is real. Even without a star, a uniformly accelerated observer would detect and Unruh flux of radiation. Despite the discussions on the choice of initial vacua, the existence of Hawking radiation is not disputed and it remains so independent of the choice of boundary conditions [15]. The study of the backreaction of Hawking radiation on the star’s interior for both vacua states would complete this part of investigation. In case (ii) the choice of Un- ruh’s vacuum produces a flux of radiation τ tr . Solutions
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Vacuum energy sequestering and graviton loops

Vacuum energy sequestering and graviton loops

means that the observable that is corrected by the vacuum energy loops – the curvature of the empty space – is UV sensitive, and must be renormalized. Its physical value is the sum total of the quantum vacuum contributions and the bare counterterm. This is a finite quantity which cannot be predicted, but must be measured. When the cutoff-dependent pieces are subtracted, the renormalized cosmological constant is a function of the finite contributions coming from all the physical scales m below the cutoff and the arbitrary subtraction scale ¯ M , where it is measured. The problem is that the renormalized cosmological constant depends on the powers of the physical scales below the cutoff, implying that it can be greatly affected by any existing heavy field beyond the threshold of local measurements at sub-TeV scales.
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A Survey about High Current Interruptions Results in Resistive Increase of Vacuum Interrupters

A Survey about High Current Interruptions Results in Resistive Increase of Vacuum Interrupters

It is also evident that the resistance across the switching contacts determines the continuous current carrying capability of the breaker. Therefore, an increase of the resistance after making and breaking operations might have an influence on this capability though it is not anticipated that a circuit breaker experiences as many full short-circuit interruptions as applied during a type test and as high a continuous current as rated. This paper lists resistances of a variety of vacuum interrupters before and after current interruption tests, correlates the resistance increase with circuit- breaker ratings and explains its origin. In particular, the impact of a modification of contact material properties such as electrical conductivity and hardness are investigated in theory and experiment.
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