Fusion Conditions Research Articles

Effect of welding current on morphology and microstructure of Al alloy T-joint in double-pulsed MIG welding

The effect of current on the morphology of Al alloy T-joint in double-pulsed metal inert gas (DP-MIG) welding process was investigated by simulation and experiment. A three-dimensional finite element model and the DP-MIG heat source of double-ellipsoidal volumetric model were developed to simulate the temperature and stress fields under different welding conditions. The macro-morphology and microstructure of welding joints at the corresponding currents were observed in the experiment. The results show that the best condition is at an average current of 90 A and current difference of 40 A, when the maximum temperature is 200 °C higher than the fusion points, with the temperature difference of about 100 °C and stress change of 10 MPa between thermal pulse and thermal base. Under these conditions, Al alloy T-joint with proper fusion condition has smooth fish-scale welding appearance and finer microstructure. Furthermore, the thermal curves and stress distribution in the experiment are consistent with those in the simulation, verifying the precision of the welding simulation.

Gaseous Shielding Gas Additives as Flux Substitute for TIG Arc Brazing

Brazing is one of the key technologies in the field of joining of metal components. To improve the wetting of brazing material and work-piece surface, it is often required to fall back on the use of flux. The application of these substances requires accuracy and is often connected with considerable expenditure and it is, just as the removal of flux residues, often an additional working step which has to be carried out manually. Within the framework of a DFG research project it has been investigated to which degree gaseous substances as addition to the shielding gas may replace conventional flux in TIG arc brazing. To this end, investigations have been carried out using different combinations of base and filler materials. Mainly monosilane as a gaseous flux substitute has been added in low concentrations to the shielding gas volume flow. The resulting brazed joints have been quantified with regard to their geometry, their fusion conditions and their chemical compositions. These qualities were then correlated and evaluated with the provided quantity of monosilane in order to identify dependencies.

Multibeam Stimulated Raman Scattering in Inertial Confinement Fusion Conditions.

Stimulated Raman scattering from multiple laser beams arranged in a cone sharing a common daughter wave is investigated for inertial confinement fusion (ICF) conditions in a inhomogeneous plasma. It is found that the shared electron plasma wave (EPW) process, where the lasers collectively drive the same EPW, can lead to an absolute instability when the electron density reaches a matching condition dependent on the cone angle of the laser beams. This mechanism could explain recent experimental observations of hot electrons at early times in ICF experiments, at densities well below quarter critical when two plasmon decay is not expected to occur.

New regime of low ion collisionality in the neoclassical equilibrium of tokamak plasmas

The neoclassical description of an axisymmetric toroidal plasma equilibrium is formulated for an unconventionally low ordering of the collisionality that suits realistic thermonuclear fusion conditions. This requires a drift-kinetic analysis to the second order of the ion Larmor radius, which yields a new contribution to the leading solution for the non-Maxwellian part of the ion distribution function if the equilibrium geometry is not up-down symmetric. An explicit geometrical factor weighs this second Larmor-radius order, low-collisionality effect that modifies the neoclassical ion parallel flow, and the ion contribution to the bootstrap current.

Fusion Rate Difference between Sublaminar Wire and Screw Fixation in Type 2 Odontoid Traumatic Fractures

Introduction Traumatic odontoid fracture type 2 is not uncommon in cervical spine trauma. Different techniques of fusion are usually applied depending on many factors with the aim of acquiring bony fusion at C1–2 segment. Material and Methods Twenty patient of traumatic type 2 odontoid fractures were operated in our institute from December 2010 till march 2014. Sublaminar wiring was done in 10 cases and the rest were operated by C1–2 screw fixation. Clinical condition and bony fusion were evaluated at 3 and 6 months. Results Fourteen patients were with improving or stationary clinical state plus good fusion signs. While six patients developed either clinical deterioration or radiological failure of fusion. Among these six patients, four cases were fused by sublaminar wire and two patients were operated by screw and rod fixation. All cases with fusion failure were re operated again. Conclusion Screw system fixation for traumatic odontoid fracture type 2 take upper hand than sublaminar wiring regarding bony fusion and clinical condition but longer time follow-up and larger series are needed.

THE DEVELOPMENT OF THE MODELING SYSTEM OF THE CALCULATION OF HEAT EXCHANGE PROCESSES AND ESTIMATION OF PARAMETERS OF THE ZONE OF VISCOPLASTIC STATE OF IRON METAL MATERIALS IN BLAST FURNACE

This report presents the development of cycles used by authors in the creation of the computer decision support system, allowing to size up an arrangement and the form of a zone of viscousplastic weights of iron metal materials (plastic zone) in a blast furnace, to carry out diagnostic of its rational configuration under really accessible information on the working blast furnace for the base period, and also to solve a complex of problems for the design period at change of operating conditions of fusion. The article reflects the functionality and the results of use of the software to solve technological problems in the blast-furnace process of OJSC Magnitogorsk Iron and Steel Works.

Anesthetic management of a rare case of craniosynostosis

Craniosynostosis is a condition of premature intrauterine fusion of sutures causing abnormal skull shape, neurological abnormalities and increased intracranial pressure. It can occur as an isolated condition or may be part of a syndrome. The key to treating an infant with craniosynostosis is early diagnosis and accurate treatment as untreated craniosynostosis can affect mental development and visual abnormalities which are linked to raised intracranial pressure. In this case, we describe the anesthetic management of a 13-month-old baby, a case of nonsyndromic craniosynostosis involving sagittal, metopic and coronal sutures posted for strip craniectomies.

The Optimum Conditions for Arc Fusion to Splice Photonic Crystal Fiber and Single Mode Optical Fiber

The Optimum Conditions for Arc Fusion to Splice Photonic Crystal Fiber and Single Mode Optical Fiber

Experimental Studies of an Ultrahigh-Speed Plasma Flow

In 1991, Turchi et al. reported evidence for a 2000 km/s aluminum plasma that originated from the upstream boundary of a wire array armature in a plasma flow switch (PFS). The 2008 article by Turchi et al. posits that if such high $Z$ plasma could instead be composed of deuterium or a deuterium–tritium mixture, then the resultant multi-keV plasma would make an effective target for magnetized plasma compression to fusion conditions. This report documents several experiments executed in an effort to achieve an ultrahigh-speed flow in a deuterium plasma. The first phase of this research concentrated on extension of the earlier work to a lower current system that would emulate the PFS used in series with an imploding liner load. The apparatus was also modified to permit pulsed injection of deuterium gas along the insulated coaxial electrodes between the PFS armature and the vacuum power feed. The experiments met with limited success, exhibiting evidence of a 550 km/s plasma flow which convected a small fraction of the total magnetic field. Two subsequent tests were conducted using foam armatures. In both cases, current prematurely shunted upstream in the vacuum feed. Several possible causes were explored for the shunting of the current. Among the modifications implemented, the gas injection system was altered to increase both the quantity of gas adjacent to the armature while facilitating an increased pressure gradient between the armature and the current feed. A series of low-energy shots were conducted to examine the impact of several proposed design modifications on current delivery to the armature. These experiments demonstrated that the hardware assembled for this investigation was unlikely to forestall breakdown in the injected gas as required by Turchi et al. Nevertheless, two experiments were conducted to evaluate performance with foam armatures. Both experiments exhibited good current delivery to the armature, behaving initially like the low-energy experiments. The magnetic flux convected downstream was greater than in any of the prior experiments, though significant work remains to demonstrate the ultrahigh-speed plasma flow concept.

Determination of Experimental Conditions of Preparation of Zeolites from Fly Ashes via Alkaline Fusion Followed by Hydrothermal Crystallization

In this study, we converted high silicon fly ashes (FA) to zeolites using a two stages conversion process: alkaline fusion followed by hydrothermal crystallization. The orthogonal experimental method was applied to design the experimental variables of alkaline fusing and hydrothermal crystallizing procedure. Alkaline fusion prior to hydrothermal synthesis was applied to collapse the FA crystalline phases and release Si content. Different from most of the research, the mixtures of NaOH and Na2CO3 were used to increase the fusion temperature in order to remove the residue carbon simultaneously. Acid solubility was used to evaluate the efficiency of alkaline fusion. Then the optimized alkali-fused FA was resolved in the NaOH solutions and the experiment conditions were designed by the orthogonal experimental method. XRD and SEM were employed to characterize the crystalline phases and microimages of the raw FA and the treated FA. Adsorption process of methylene blue was applied to simulate the adsorption ability of the fly ash zeolites. Finally, the optimized conditions of alkaline fusion and hydrothermal treatment were concluded.

Experimental demonstration of fusion-relevant conditions in magnetized liner inertial fusion.

This Letter presents results from the first fully integrated experiments testing the magnetized liner inertial fusion concept [S. A. Slutz et al., Phys. Plasmas 17, 056303 (2010)], in which a cylinder of deuterium gas with a preimposed 10 Taxial magnetic field is heated by Z beamlet, a 2.5 kJ, 1 TW laser, and magnetically imploded by a 19 MA, 100 ns rise time current on the Z facility. Despite a predicted peak implosion velocity of only 70 km = s, the fuel reaches a stagnation temperature of approximately 3 keV, with T(e) ≈ T(i), and produces up to 2 x 10(12) thermonuclear deuterium-deuterium neutrons. X-ray emission indicates a hot fuel region with full width at half maximum ranging from 60 to 120 μm over a 6 mm height and lasting approximately 2 ns. Greater than 10(10) secondary deuterium-tritium neutrons were observed, indicating significant fuel magnetization given that the estimated radial areal density of the plasma is only 2 mg = cm(2).

Investigation into Fusion Feasibility of a Magnetized Target Fusion Reactor: A Preliminary Numerical Framework

The efforts to engineer devices to produces conditions suitable for nuclear fusion on earth have made significant leaps and bounds in recent years due to improved technology and engineering methods. Magnetized target fusion, or magneto-inertial fusion, involves the inertial compression of a pre-magnetized plasma, using high magnetic fields to insulate the plasma, thereby allowing slower and lower convergence compression than achievable by inertial techniques alone. One particular form of MTF (suggested by general fusion) involves using an intense pressure wave transmitted through a dense medium, growing in intensity due to focusing, and finally reaching a plasma and compressing it. Our model consists of a spherically symmetric domain with moving boundaries that we solve numerically through a coordinate transformation and a flux-limited finite volume method. Our work ventures towards a proof of concept, both of a mathematical technique to solve nonlinear conservation laws with moving boundaries and of the notion that current designs being considered show potential for successful fusion conditions. Our work also includes a sensitivity analysis to estimate the optimal conditions for such a reactor.

Genome shuffling of Aspergillus glaucus HGZ-2 for enhanced cellulase production.

The production of cellulase from Aspergillus glaucus HGZ-2 was improved by using genome shuffling. The starting populations, obtained by UV irradiation, were subjected to recursive protoplast fusion. The optimal conditions for protoplast formation and regeneration were 7mg/ml snailase and 5mg/ml cellulase at 34°C for 3.0h using 0.7M NaCl as an osmotic stabilizer. The protoplasts were inactivated under UV for 30min or heated at 50°C for 50min, and a fusant probability of about 100% was observed. The positive colonies were created by fusing the inactivated protoplasts. The optimal conditions for protoplast fusion were PEG6000 concentration of 35%, CaCl2 concentration of 0.02M, and incubation time of 12min. After two rounds of genome shuffling, one strain (Y) was obtained. Its filter paper cellulase (FPase) and carboxymethyl cellulase (CMCase) activity reached 71 and 70U/ml, respectively, which were increased by 1.95-fold and 1.72-fold in comparison with that of its ancestor strain. The results indicated that genome shuffling was an efficient means for the improved production of cellulases by A. glaucus HGZ-2.

Surface Inspection of Cu-Cu Non-Thermal Compression Bonding for Wafer-to-Wafer 3D Stacking

Backside illuminated CMOS image sensors with a 3D stacked architecture, where the pixel array is attached on top of the logic circuit, was introduced and have just come to the market. Image sensor featuring 3D stacking was realized by connection between the interconnect layers of the top and bottom parts using vertical type through-silicon via (TSV).1 Cu bonding technology for 3D integration has been studied and widely applied.2As Wafer-to-wafer bonding process is now being used widely and matured through the production of Backside illuminated CMOS image sensors, Copper-copper bonding provides an attractive route to 3D stacked image sensor since it creates a strong metal bond and enables vertically electrical connection during the bonding process.Specific pre-bonding surface conditioning is necessary to insure high bonding quality of patterned Cu wafers using Cu-Cu non-thermo compression bonding for wafer-to-wafer 3D stacking. Surface preparations for the hybrid fusion bonding such as removal of Cu oxide, Cu surface protection and optimized CMP planarization patterned Cu surfaces have been studied,3 but the study on plasma condition for hybrid fusion bonding is relatively a few. The work described here is investigating of the plasma-related Cu patterned hybrid surface preparation under different plasma conditions.The main physical mechanisms about Cu-Cu non thermal compression bonding are spontaneous adhesion of hydrophilic surfaces followed by Cu diffusion across the bonding interface when Cu-Cu contact is reached (diffusion bonding) have been previously reported.4 The property of Cu dielectric diffusion barriers used in ULSI is hydrophobic. For the efficient bonding of hydrophobic-hydrophobic layers, surface conversion process is introduced.5 In the case of Cu-patterned hybrid bonding in typical Cu metallization layer in ULSI, Trade-off between dielectric diffusion barrier and Cu cannot be avoidable by surface conversion process.During the Cu-patterned hybrid bonding development, the common electrical failed areas were found.To investigate the failure mechanism, influence of plasma condition on the activation of wafer surface and bonding quality was studied. The wafer surface was examined by X-ray photoelectron spectroscopy (XPS), surface roughness, and observation of differential work function uniformity over a full wafer area caused by plasma-induced charge.6The ChemetriQ NVD inspection system from Qcept Technologies was used to inspect differential work function uniformity.After implementing plasma treatment applied in bonding process, Non-uniformity of a charge map and different plasma influence over a full wafer area were shown, even there was no difference through the AFM analysis. For the optimization of the bonding process, especially plasma process, a method to examine the surface condition in this paper makes it possible to monitor the plasma process and improve bonding process

Synthesis of mesoporous silica materials from municipal solid waste incinerator bottom ash

Incinerator bottom ash contains a large amount of silica and can hence be used as a silica source for the synthesis of mesoporous silica materials. In this study, the conditions for alkaline fusion to extract silica from incinerator bottom ash were investigated, and the resulting supernatant solution was used as the silica source for synthesizing mesoporous silica materials. The physical and chemical characteristics of the mesoporous silica materials were analyzed using BET, XRD, FTIR, SEM, and solid-state NMR. The results indicated that the BET surface area and pore size distribution of the synthesized silica materials were 992m2/g and 2–3.8nm, respectively. The XRD patterns showed that the synthesized materials exhibited a hexagonal pore structure with a smaller order. The NMR spectra of the synthesized materials exhibited three peaks, corresponding to Q2 [Si(OSi)2(OH)2], Q3 [Si(OSi)3(OH)], and Q4 [Si(OSi)4]. The FTIR spectra confirmed the existence of a surface hydroxyl group and the occurrence of symmetric Si–O stretching. Thus, mesoporous silica was successfully synthesized from incinerator bottom ash. Finally, the effectiveness of the synthesized silica in removing heavy metals (Pb2+, Cu2+, Cd2+, and Cr2+) from aqueous solutions was also determined. The results showed that the silica materials synthesized from incinerator bottom ash have potential for use as an adsorbent for the removal of heavy metals from aqueous solutions.

Magnetic Reconnection in Plasma under Inertial Confinement Fusion Conditions Driven by Heat Flux Effects in Ohm’s Law

In the interaction of high-power laser beams with solid density plasma there are a number of mechanisms that generate strong magnetic fields. Such fields subsequently inhibit or redirect electron flows, but can themselves be advected by heat fluxes, resulting in complex interplay between thermal transport and magnetic fields. We show that for heating by multiple laser spots reconnection of magnetic field lines can occur, mediated by these heat fluxes, using a fully implicit 2D Vlasov-Fokker-Planck code. Under such conditions, the reconnection rate is dictated by heat flows rather than Alfvènic flows. We find that this mechanism is only relevant in a high β plasma. However, the Hall parameter ωcτei can be large so that thermal transport is strongly modified by these magnetic fields, which can impact longer time scale temperature homogeneity and ion dynamics in the system.

Synthesis of Some New Phthalimides as Anti-metabolic Agents with Chemotherapeutic Effects

A series of new phthalimides 1(a-f) were synthesized via reaction phthalic anhydride with different amino acids under fusion conditions. Esterification of N-phthaloyl acid derivatives 1(a-f) with methanol in the presence of SOCl2 to producing the corresponding esters 2(a-f). Which on reaction with hydrazine hydrate in boiling n-butanol afforded the corresponding N-phthaloyl acid hydrazides 4(a-f) Reaction of compound (4a) with different aldehydes and ketones yielded the corresponding hydrazone derivatives 5(a-d). Some new phthalimides linked to hetero cyclic moieties such as benzimidazoles, benzoxazines and quinazolines were synthesized. The structure of the synthesized compounds was confirmed from their analytical and spectral data such as, IR spectra, 1H-NMR and mass spectra. Antimicrobial against two types of bacteria and anticancer activity for some of the synthesized imides were evaluated. The results showed that most of them have a good antimicrobial and anticancer activities.

Optical Surface Cleanliness Inspection, Degradation and Maintaining in High Power Laser System

High Power Laser System (HPLS) is a large optical instrument, provides extremely high temperature and pressure conditions for inertial confinement fusion (ICF) and high-energy-physics research. It contains large number of optics and which would be easily damaged due to high fluence of laser power. The contamination control of optical surfaces has a great significance to ensure the performance of the system and decrease costs. This paper discussed the background and development of cleanliness control techniques in high power laser systems, including contamination induced laser damage (CILD), contamination inspection, optical surface cleanliness degradation and maintaining.

Selective Breeding of Oxygen-Tolerant and Oxalate-Degrading Lactic Acid Bacteria by Protoplast Fusion

Bifidobacterium lactis with oxalate-degrading capacity can efficiently reduce the oxalate in vivo, and it can be used to prevent and treat kidney stone diseases. While Bifidobacterium lactis is poorly oxygen-tolerant, which hinders it from being as microbial ecological agents. To obtain oxygen-tolerant and oxalate-degrading lactic acid bacteria, protoplast fusion technology was used between B. lactis and L. acidophilus. Under the optimum conditions of protoplast fusion with PEG 6000 concentration 50%, the fusion time 7 min, the fusion temperature 30°C, the concentration of CaCl2 0. 02mol/ L and the concentration of MgCl2 0.5mol/ L, the fusion rate reached 7.6%, and three oxygen-tolerant fusant showing that the level of oxalate degradation were similar with B. lactis was obtained. The fusants of SZY1-7 and SZY2-1 could tolerance to pH 2.5 and 0.5% (w/v) bile salt.

SnRNAs are reduced in the syncytiotrophoblast: a possible mechanism for regulation of human placental protein production

The multinucleate syncytiotrophoblast of the human placenta is formed by fusion of the underlying cytotrophoblast progenitor cells. The large surface area of the syncytiotrophoblast is necessary for transport functions while it also serves as the site of synthesis of hormones and steroids. Studies of syncytiotrophoblast transcription are puzzling, demonstrating that many of the nuclei in the multinucleated syncytium are transcriptionally inactive. To further elucidate RNA activity in the syncytiotrophoblast, we investigated expression of snRNAs involved in RNA splicing. Using RNA in situ hybridization, we observed that snRNAs were markedly reduced in the syncytium throughout the course of pregnancy. Recapitulating these results in primary trophoblasts and in trophoblast cell lines in vitro, we found, using qRT-PCR and RNA in situ hybridization, that snRNA expression is reduced in trophoblasts cultured under fusion conditions. Our finding that snRNA is markedly reduced in the syncytiotrophoblast suggests that the placenta has evolved a balance between the large surface area essential for its transport function and the need to regulate protein production in the multinucleated syncytium.