Solid Back Research Articles

Solidification Path Calculation of ternary Al-Cu-Mg alloys in Al rich corner

ABSTRACT The liquid solidification paths of ternary eutectic and quasiperitectic Al-Cu-Mg alloys in Al-rich corner were calculated using an extended microsegregation model. The user’s programs were coupled with CALPHAD software for calculating the thermodynamic data of the investigated alloys. The influences of initial composition, average solidification rate, assumption of dendrite morphology, diffusion coefficient and the united solid back diffusion (SBD) parameter Фn on solidification paths were investigated. It was found that differences of the above parameters could greatly affect the liquid solidification path, types and quantities of the precipitated phases, and concentration of solutes in liquid phase. Solidification experiments were carried out with four Al-Cu-Mg alloys to verify the accuracy of the calculation, and reasonable agreements were obtained between the predicted solidification paths and the experiment results.

One-Pot Synthesis of Colloidal Hybrid Au (Ag)/ZnO Nanostructures with the Participation of Maleic Acid Copolymers.

One-pot synthesis of colloidal Au/ZnO and Ag/ZnO nanohybrid structures was carried out. The copolymers of maleic acid-poly(N-vinyl-2-pyrrolidone-alt-maleic acid), poly(ethylene-alt-maleic acid), or poly(styrene-alt-maleic acid) were used as templates for the sorption of cations of metals-precursors and stabilization of the resulting nanoheterostructures. Simultaneous production of two types of nanoparticles has been implemented under mild conditions in an aqueous alkaline medium and without additional reagents. Equimolar ratios of the metal cations and appropriate load on all copolymers were used: molar ratio of maleic acid monomeric units of copolymer/gold (silver)cations/zinc cations was 1/0.15/0.23 (1/0.3/0.15). The process of obtaining the heterostructures was studied using UV-Vis spectroscopy. The kinetics of the formation of heterostructures was influenced by the nature of the maleic acid copolymer and noble metal cations used. A high reaction rate was observed in the case of using zinc and gold cations-precursors and a copolymer of maleic acid with N-vinylpyrrolidone as a stabilizer of nanoparticles. The structure of the synthesized polymer-stabilized heterostructures was studied using instrumental methods of analysis-XPS, FTIR, PXRD, and TEM. Under the conditions used, stable colloidal solutions of heterodimers were obtained, and such structure can be converted to a solid state and back without loss of properties.

Analysis of permafrost effect on water exchange processes

The article focuses on the importance of studying the water exchange role of the permafrost, which currently occupies a quarter of the Earth's land and is 1.5 km deep in some regions, as well as assessing the permafrost impact on the formation of surface and ground water resources and regime. First of all, the permafrost water exchange function is associated with the freezing of water-saturated rocks and thawing of ice-saturated ones. The author gives individual consideration to the water exchange role of the active layer and the effect of the permafrost long-term dynamics on water exchange direction and scale. The water exchange function of the active layer appears due to the seasonal phase transitions of groundwater from a liquid to a solid state and back. Thus, the volume of water formed by the thawing of underground ice accumulated in the active layer in winter has been estimated about 4·1012 m3. In this regard, it is proposed to give cryohydrogenic part associated with the seasonal transitions of groundwater from the liquid to solid state and back in the active layer of the cryolithozone independent consideration within the hydrological (climatic) cycle of the natural water circulation. It is most certain that the permafrost water exchange function is more significant being associated with longterm permafrost development dynamics under the influence of periodic dramatic climate fluctuations. Thus, during the Holocene climatic optimum about 4.5·1015 m3 of underground ice was converted to the liquid phase. The intensity of water formed from the melting of this amount of ice inflowing its surface and underground reservoirs has been estimated about 820 km3 per year. This fact considered, the author proposes to consider the cryolithogenic part separately in the geological cycle of the natural water cycle.

Wheelchair backs that support the spinal curves: Assessing postural and functional changes

Objective: To compare outcomes using a wheelchair back designed to support the natural seated spinal curves versus an upholstered back that promotes posterior pelvic tilt and thoracolumbar kyphosis. Design: Cross-over intervention. Setting: Two free-standing spinal cord injury (SCI) model system hospitals. Participants: Fifty adults with motor complete SCI C6-T4, between the ages of 18–60 years who use a manual wheelchair for mobility were recruited from a convenience sample. Intervention: Each participant’s wheelchair back support was removed and replaced by an upholstered back and a solid back in randomized order. Postural and functional outcomes, pain, and satisfaction were evaluated using each back. Outcome measures: Seated postural measurements included pelvic angle, spinal angle of kyphosis and linear measurement of spine. Functional outcomes included vertical forward reach, one stroke push, timed forward wheeling, ramp ascent and descent. Numerical pain rating and a satisfaction survey provided input pertaining to both backs. Results: The solid back demonstrated significance in seated postural measurements. Participants using the solid back trended to higher scores in functional outcome measures including vertical forward reach, one stroke push and timed ramp ascent. Participants reported increased satisfaction with comfort and stability with the solid back. Conclusions: This pilot study demonstrated that a wheelchair back, which supports the seated spinal curves improves upright posture, functional reach, and wheelchair propulsion skills. Further research is necessary to demonstrate statistical findings as well as to assess back height and lateral support.

GC-MS analysis and pharmacological potentials of Neurada procumbens.

Muhammad Munawar Hayat*, Muhammad Uzair Department of Pharmaceutical Chemistry, Bahauddin Zakariya University, Multan, 60800, Pakistan Introduction The Neurada procumbens is a desert plant belongs to family Neuradaceae and traditionally used a nerve tonic and cooling agent with the name of herbal preparation “Thadal” in summer by local people. Its folkloric uses are as anthelmintic, anticonvulsant, laxative, infestinal problems, eczema, infections, rheumatism and sexual problems [1]. The leaves and fruits of the plant are used for medicinal purposes and whole plant is a source of fodder for camel [2]. It is an annual prostrate densely tomentose herb. The local name of Neurada procumbens is “Chapperi Booti” and “Als’dan”. According to Flora of West Pakistan, there is only single species distributed in Pakistan from the genus Neurada [3]. The influence of aqueous extract of N. procumbens when administered orally increases the blood pressure of rats. The study provides that elevation of blood pressure was due to vasoconstriction on the aortic strips of rats in vitro [4]. It is also reported that ethanolic extract of N. procumbens reduced the blood pressure in rabbits [5]. Quinone oxidoreductase 1 inducer activity of plant is also reported [6]. Recently, some flavonoids are isolated from N. procumbens in Egypt [7]. Literature survey revealed that there is too much diverse folkloric use of the plant in residants of Cholistan desert but little work regarding biological screening and enzymatic inhibition studies of N. procumbens has been done. Therefore, it was need to explore the therapeutical potential of the plant. The objectives of present study were to investigate the secondary metabolites, chemical constituents and enzymatic or biological activities. Despite the multiple ethanomedicinal uses of N. procumbens in diarrhea, dysentery, diabetes, inflammation, ulcer, edema, asthma, oxidative stress and skin problems, no research work is available with respect to its effectiveness in these diseases. The present work on the two crude extracts of the plant N. procumbens was undertaken for various biological and enzyme inhibition activities to scientifically rationalize the traditional uses and also includes the phytochemical screening or evaluation of the plant. Materials and Methods Collection and extraction of plant Objective: Neurada procumbens L is a medicinal herb with diverse folk history and is traditionally used to treat diarrhea, dysentery, diabetes, eczema, anticonvulsant, rheumatism, laxative, infestinal and gastrointestinal problems, sexual problems, anthelmintic, infections and respiration function. The aim of this study was to prove the uses of plant N. procumbens in gastrointestinal and respiratory disorders scientifically. Method: The phytoconstituents were identified by GC-MS technique. In this study, twelve (12) different kinds of in vitro biological and enzyme inhibition activities were performed to explore the diverse folkloric use of the plant scientifically. Results: On phytochemical screening, it was proved that plant N. procumbens is rich source of flavonoids as dichloromethane and methanol extracts have 143.45 ± 1.25 and 200.69 ± 1.97 mg QE/g of extract, respectively. By GC-MS analysis, nine (9) compounds in dichloromethane extract and six (06) in methanol extract were detected. The dicloromethane extract of whole plant of N. procumbens showed anti-lipooxygenase, anti-chymotripsin, anti- alpha glucosidase, anti-urease and anti-tyrosinase activities, whereas methanol extract showed antioxidant, anti-alpha glucosidase, anti-urease, anti-tyrosinase, anticarbonic anhydrase II, spasmolytic and bronchorelaxant activities. Conclusion: The study proofs the folk medicinal use of N. procumbens to treat diabetes, diarrhea, and improvement in gastrointestinal and respiration functions which justifies the pharmacological importance of plant. Moreover, this study can be considering a solid back ground for further in vivo studies.

Flexible OPV modules for highly efficient indoor applications

The comparison of solution processed organic photovoltaics with two roll-to-roll coated electron transport layers (ETL), as well as printed grid or solid back electrodes provides insight into the future of R2R fabricated architectures. The variation in performance of the R2R slot-die coated zinc oxide (ZnO) versus the tin oxide (SnO2), showed a clear dependence on the spectrum of the illumination source. It was found that under indoor light conditions (200–1000 lux LED and fluorescent sources) the SnO2 outperformed the ZnO with highest efficiencies near 13% and 10% respectively. This is in contrast to results obtained under 1 Sun (AM 1.5) in which the cells fabricated with a ZnO ETL had a higher power conversion efficiency than those prepared with SnO2. The results also confirm the significance of the layout of the printed silver back contact; in which cells with the grid structure outperformed those with full coverage by approximately 35% for ZnO and just under 10% for SnO2 (all light conditions). The combination of a R2R coating and S2S printing process to prepare modules with 8 cells in series (PET/ITO/SnO2/PV2001:PCBM/PEDOT:PSS/silver grid) resulted in a PCE of 13.4% under indoor office light conditions.

Applicability of 3D Spectral Element Method for Computing Close-Range Underwater Piling Noises

Pile driving is used for constructing foundation supports for offshore structures. Underwater noise, induced by in-water pile driving, could adversely impact marine life near the piling location. Many studies have computed this noise in close ranges by using semi-analytical models and Finite Element Method (FEM) models. This work presents a Spectral Element Method (SEM) wave simulator as an alternative simulation tool to obtain close-range underwater piling noise in complex, fully three-dimensional, axially-asymmetric settings in the time domain for impacting force signals with high-frequency contents (e.g., frequencies greater than 1000[Formula: see text]Hz).The presented numerical results show that the flexibility of SEM can accommodate the axially-asymmetric geometry of a model, its heterogeneity, and fluid-solid coupling. We showed that there are multiple Mach Cones of different angles in fluid and sediment caused by the difference in wave speeds in fluid, a pile, and sediment. The angles of Mach Cones in our numerical results match those that are theoretically evaluated. A previous work18had shown that Mach Cone waves lead to intense amplitudes of underwater piling noise via a FEM simulation in an axis-symmetric setting. Since it modeled sediment as fluid with a larger wave speed than that of water, we examined if our SEM simulation, using solid sediment–fluid coupling, leads to additional Mach Cones. Because this work computes the shear wave in sediment and the downward-propagating shear wave in a pile, we present six Mach Cones in fluid and sediment induced by downward-propagating P- and S-waves in a pile in lieu of two previously-reported Mach Cones in fluid and sediment (modeled as fluid) induced by a downward-propagating P-wave in a pile. We also showed that the amplitudes of the close-range underwater noise are dependent on the cross-sectional geometry of a pile. In addition, when a pile is surrounded by a solid of an axially-asymmetric geometry, waves are reflected from the surface of the surrounding solid back to the fluid so that constructive and destructive interferences of waves take place in the fluid and affect the amplitude of the underwater piling noise.

Thick Layered Semiconductor Devices with Water Top-Gates: High On–Off Ratio Field-Effect Transistors and Aqueous Sensors

Layered semiconductors show promise as channel materials for field-effect transistors (FETs). Usually, such devices incorporate solid back or top gate dielectrics. Here, we explore deionized (DI) water as a solution top-gate for field-effect switching of layered semiconductors including SnS2, MoS2, and black phosphorus. The DI water gate is easily fabricated, can sustain rapid bias changes, and its efficient coupling to layered materials provides high on-off current ratios, near-ideal subthreshold swing, and enhanced short-channel behavior even for FETs with thick, bulk-like channels, where such control is difficult to realize with conventional back gating. Screening by the high-k solution gate eliminates hysteresis due to surface and interface trap states and substantially enhances the field-effect mobility. The onset of water electrolysis sets the ultimate limit to DI water gating at large negative gate bias. Measurements in this regime show promise for aqueous sensing, demonstrated here by the amperometric detection of glucose in aqueous solution. DI water gating of layered semiconductors can be harnessed in research on novel materials and devices, and it may with further development find broad applications in microelectronics and sensing.

Microstructure and Stress-Rupture Property of Large-Scale Complex Nickel-Based Single Crystal Casting

The microstructure and stress-rupture property of the large-scale complex single crystal (SX) casting DD10 were investigated in high-rate solidification process. It is found that the primary dendrite arm spacing (PDAS) does not increase monotonically with the height increase. When across the platform, the temperature gradient increases due to the effect of platform, and the corresponding PDAS decreases. The distribution of eutectic volume fraction in large-scale complex SX casting is affected by PDAS, solid back diffusion, and the development of high order dendrites. The eutectic volume fraction contained in the sample taken below the platform decreases with the height increase. While the eutectic volume fraction contained in the sample taken upper the platform increases gradually with the height increase. After heat treatment, most of the γ/γ′ eutectics are eliminated and the components are distributed uniformly. The similar stress rupture properties of the samples at different heights in the same direction are obtained.

Solidification path calculations of Al-Zn-Mg alloys in Al-rich corner

The solidification paths of Al-Zn-Mg alloys in the Al-rich corner were investigated. The thermodynamic data for the calculation are obtained by direct coupling with the CALPHAD software Thermo-Calc via its TQ6-interface and the COST2 database. The influences of the initial compositions and the extent of solid back diffusion on the solidification path were numerically investigated by sample calculation of the ternary Al-Zn-Mg alloys. The calculation results of solidification paths of the selected alloys: Al-5Zn-3Mg (in wt.%), Al-5Zn-10Mg, Al-2.5Zn-15Mg, Al-10Zn-20.5Mg, Al-8Zn-25Mg, were: L→(L+α-Al), L→(L+α-Al)→(L+α-Al+TAU), L→(L+α-Al)→(L+α-Al+AlMg_β), L→(L+α-Al)→(L+α-Al+TAU)→(L+α-Al+TAU+AlMg_β), L→(L+α-Al)→(L+α-Al+AlMg_β)→(L+α-Al+TAU+AlMg_β), respectively. The results show that the initial compositions and the extent of solid back diffusion have a great influence on solidification path, and the amounts of eutectic phase increase with the decrease of the solid back diffusion coefficient. The equilibrium solute partition coefficients for Zn and Mg in alloys are also calculated and their influence on micro-segregation in the primary solidification of Al-5Zn-10Mg alloy is analyzed.

ENVIRONMENTAL AND ECONOMIC ASSESSMENT OF THE OPERATIONS OF SOLID WASTE RECYCLING COMPARATIVE STUDY BETWEEN RURAL AND URBAN AREAS

The solid waste problem with one of the major environmental problems attached by countries currently growing interest not only harmful to its effects on public health and the environment and distortion of the face of civilization, but also the social and economic impacts in addition to the high costs incurred by the states spending was in a position to provide or unconscious could have avoided, and perceived problem of solid waste and recycling, as one of the more issues that cause pollution of the environment in Egypt, especially the province of Qaliubiya specific (rural and urban), taking into account that it is a good source of the national economy if they are utilizing them right and thus the consequent achieve social and environmental economic return, and represents the main goal of the study to provide the raw materials that go into the various industries that can be rotated with the result of the ease of use of natural resources and sustainable use as a result of industrial activity, reduce dependence on polluting energy sources, and reducing air and water pollution soil and environmental degradation in general, improve the environmental situation and the consequent improvement of the health status of the community. In the light of production and industrialization occur an increase in waste generated from operations, which are discharged into the surrounding environment and cannot be absorbed due to their limited absorptive rates, so I dealt with message transfer the experiences of some countries in dealing with solid waste. Researcher depends on the descriptive and analytical approach and the methodology of the social survey, the study was conducted on a sample of (297) through questionnaires addressed to the Gentlemen of the staff on the recycling operations of the Ministry of Environment, Local Unit, urban, rural, and describes the questionnaire validity and reliability by using the method of retail midterm to calculate stability, using Brown's equation, and Spearmen then self-honesty account, to illustrate the value of reliability coefficient, honesty, the study found, and no statistically significant relationship between the recycling of solid waste and environmental effects and economic society, environmental protection and the preservation of public health, and increasing recycling operations, through the first axis following themes: the problem is the accumulation of solid waste is one of the most important environmental problems in Egypt, and that must be a clear mechanism for the development of safe disposal and reuse through recycling in other areas. The second axis: Failure to use and recycling of solid waste back into the environmental and economic adverse effects Axis III: The recycling and treatment process and the re-use of a large economic return lead at the same time to maintain and not to waste natural resources as well as increased economic return study confirmed that take advantage of the solid waste solid waste and turn it into an economic commodity is important, and has the highest priority in an effort to improve the environmental situation in Egypt. You can take advantage of the solid waste after sorting and processing to extract electrical energy where offset the shortage of conventional energy sources through a feasibility study the possibility to benefit from the US experience to produce electricity of solid waste, which turned out to be every 1 ton of solid waste produces 1 MW Electricity. Transparency and clarity in the presentation of national problems related to recycling of solid waste and encourage investment in recycling products, either through exemptions or certain advantages implement and achieve a national campaign to educate residents Qaliubiya to separate solid waste from upstream into two parts: organic or food leftovers in the department and the rest of waste waste non-membership in another section so as to take advantage of them in recycling with the expansion of media awareness of health and environmental and economic damage resulting from the burning of waste and outreach operations of the various sectors of the community of the importance of recycling and reuse of solid waste and introduce them to its benefits health, environmental and economic paybacks campaigns project.

THE HYDRODYNAMIC CHARACTERISTICS OF AN INCLINED SUBMERGED POROUS PLATE WITH ROCK FILLED STRUCTURE

In this paper, we investigate the hydrodynamic efficiency of normal incident waves interacting with an absorbing system. The wave absorbing system consists of a submerged permeable structure filled with rock, a solid back wall, and a submerged horizontal or slightly inclined porous plate. Using a linear wave theory assumption, a multi-domain BEM (MBEM) model was created to calculate and discuss the reflection coefficients, free surface wave profiles, total wave force on the solid wall, and the horizontal and uplift forces acting on the porous plate of the water waves from several properties of the breakwater. The numerical model was calibrated using previous numerical studies to act as limiting cases for a partially submerged impermeable structure and a horizontal porous plate with a solid back wall. The accuracy of the solution is demonstrated by comparing the numerical values with those obtained from other analytical solutions. From the numerical results, the wave dissipation effect from the permeable rock-filled structure was found to perform better than expected when compared to an impermeable structure. In the case of a horizontal porous plate, the smaller submergence depth of the plate results in a smaller reflection coefficient. The larger the porous effect parameter, the smaller the value of the reflection coefficient and the larger the porous effect parameter, the greater the ability of the porous plate to reduce the uplift forces.

Ruthenium Volatilisation from Reprocessed Spent Nuclear Fuel – Studying the Baseline Thermodynamics of Ru(III)

Ruthenium is a fission product possessed of two relatively long lived isotopes, 103Ru and 106Ru, both of which form part of the Highly Active (HA) waste raffinate during spent nuclear fuel reprocessing. During reprocessing ruthenium, which may be in the form of the RuNO3+ complex, encounters temperatures conducive to volatilization. Due rutheium’s high specific radioactivity it is important to understand the mechanism by which volatilisation occurs. Here we use combined CV, RDE and electrochemical microgravimetry experiments in a study of the the RuCl3 system for the first time. We do this in the interest of establishing NO-free Ru(III) baseline behaviour so as to support future studies on NO complexed ruthenium. Using wide aqueous solvent window carbon electrodes we have observed discrete oxidations to a solution phase Ru(III)–Ru(IV)–Ru(III) trimer, to solid RuO2 and volatile RuO4. We have also observed and assigned discrete reductions of solid RuO2 back to Ru(III) and Ru(III) reduction to ruthenium metal.

Effects of scaling in metal hydride materials for hydrogen storage and compression

For the first time the dependence of thermodynamic parameters of hydrogen desorption process on sample scale (weight) was discovered experimentally for the desorption isotherms of 100g and 500g samples of LaFe0.1Mn0.3Ni4.8. The scale effect leads to decreasing of the equilibrium pressure for the larger sample, the pressure difference is ΔPscale=-0.15±0.03MPa at 100°С, and is in the range ΔPscale=-0.5to-0.3MPa at 150°С. In our opinion the scale effect is determined by elastic strains due to the mutual influence of particles while phase transition from hydride to solid solution and back in large-scale fine–disperse beds of AB5-type compounds. Scale effect has no influence on the behaviour of pure hydride phase and is absent for small samples. The value of hydrogen chemical potential change is proposed for the description of scale effect, average values are equal ΔμHscale=-310±30J/mole H for 100°C and ΔμHscale=-260±30J/mole H for at 150°C.

Graphene surface plasmons at the near-infrared optical regime

Graphene has been identified as an emerging horizon for a nanoscale photonic platform because the Fermi level of intrinsic graphene can be engineered to support surface plasmons (SPs). The current solid back electrical gating and chemical doping methods cannot facilitate the demonstration of graphene SPs at the near-infrared (NIR) window because of the limited shift of the Fermi level. Here, we present the evidence for the existence of graphene SPs on a tapered graphene-silicon waveguide tip at a NIR wavelength, employing a surface carrier transfer method with molybdenum trioxides. The coupling between the graphene surface plasmons and the guiding mode in silicon waveguides allows for the observation of the concentrated field of the SPs in the tip by near-field scanning optical microscopy. Thus the hot spot from the concentrated SPs in the graphene layer can be used as a key experimental signature of graphene SPs. The NIR graphene SPs opens a new perspective for optical communications, optical sensing and imaging, and optical data storage with extreme spatial confinement, broad bandwidth and high tunability.

Numerical Validation of a Time Domain Perforated Plate Model with Nonlinear and Inertial Effects

A time domain perforated plate model based on the "homogenization" concept is presented; the dynamic porous wall model. This model takes into account linear and nonlinear losses as well as inertial effects due to the unsteady flow in the vicinity of the holes. A numerical validation of the dynamic porous wall model is performed via the computation of the impedance versus frequency for an acoustic liner consisting of a solid wall back sheet and a perforated face sheet, separated by a given distance. Two types of unsteady flow are considered; firstly 3D LES in which the holes in the perforated face sheet are fully resolved, and secondly 2D URANS simulations in which the dynamic porous wall model is used to include the effects of the perforated face sheet. Comparisons of the results show that the new dynamic porous wall model captures both nonlinear and inertial effects well.

A General Analytical Model of Permanent Magnet Eddy Current Couplings

An improved practical two-dimensional model for the analytical calculation of the magnetic field distributions in permanent magnet (PM) eddy current couplings is presented to obtain the torque characteristics. By establishing the Cartesian coordinate reference system on the rotating conductor, the PM region is treated as a source of traveling wave magnetic field and then the multi-layer boundary value problem is solved. The formulation for the magnet blocks, the eddy current and saturation effects in the solid secondary back iron, and the equivalence relationships between typical PM shapes, are all reasonably taken into account. Calculation results produced by the proposed analytical model are compared with those from the nonlinear finite element method and experimental measurement.

Prediction of the solidification path of Al-4.37Cu-27.02Mg ternary eutectic alloy with a unified microsegregation model coupled with Thermo-Calc

Abstract An extended unified microsegregation model with solid back diffusion effects and five different dendrite morphologies was used to investigate the solidification path of Al-4.37Cu-27.02Mg (wt.%) ternary eutectic alloy at different cooling rates and solid back diffusion coefficients, coupled with Thermo-Calc. It was indicated that the cooling rates (Rf ) had no obvious effect on the solidification path which was (L + α) → (L + α + T) → (L + α + β + T); but the solid back diffusion coefficient (Φ) had a great effect on the solidification path, which evolved gradually from (L + α) → (L + α + T) → (L + α + β + T) into (L + α) → (L + α + T) when Φ increased from 0 to 1. The volume fractions of primary α phase (V α), binary eutectic (V 2E) and ternary eutectic (V 3E) at each solidification path were calculated. It was shown that V 2E decreased with the increase of Rf whereas V 3E increased and V α was almost invariant. The dependence of V 2E, V 3E and Rf were determined by linear regression analysis given as: V 2E = −2.5lgRf + 47.5; V 3E = 6.4lgRf + 47. Increase in Φ lead to increases in V α and V 2E and decrease in V 3E. The predicted soldification paths and volume fractions of Al-4.37Cu-27.02Mg ternary eutectic alloy at different cooling rates were in good agreement with experimental results.

1214 TEMPORARY TARGETED HEMOSTASIS USING A REVERSE THERMOSENSITIVE POLYMER TO FACILITATE BLOODLESS PARTIAL NEPHRECTOMY

You have accessJournal of UrologyTechnology & Instruments: Robotics/Laparoscopy1 Apr 20111214 TEMPORARY TARGETED HEMOSTASIS USING A REVERSE THERMOSENSITIVE POLYMER TO FACILITATE BLOODLESS PARTIAL NEPHRECTOMY Niall Harty, Spencer Kozinn, Jessica DeLong, Ali Moinzadeh, Sebastian Flacke, James Benn, John Libertino, and Peter Madras Niall HartyNiall Harty Burlington, MA More articles by this author , Spencer KozinnSpencer Kozinn Burlington, MA More articles by this author , Jessica DeLongJessica DeLong Burlington, MA More articles by this author , Ali MoinzadehAli Moinzadeh Burlington, MA More articles by this author , Sebastian FlackeSebastian Flacke Burlington, MA More articles by this author , James BennJames Benn Woburn, MA More articles by this author , John LibertinoJohn Libertino Burlington, MA More articles by this author , and Peter MadrasPeter Madras Burlington, MA More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.870AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Previous work has demonstrated that Lumagel™, a non-toxic, non-ionic polymer with reverse thermosensitive properties, may be used to obtain a bloodless operative field for robotic partial nephrectomy in a porcine model. We extend this work to laparoscopic and open partial nephrectomy, in which we obtain targeted renal ischemia for resection while allowing normal perfusion to the remaining kidney. We adapt our technique to allow main renal artery occlusion and compare polymer occlusion to clamping in this setting. To determine the role of Lumagel™ in larger renal vessels, both swine and calf experiments were performed. METHODS Seven pigs and three calves were included in this study. Five pigs underwent a total of 8 segmental and 5 main renal artery occlusions, while two pigs underwent main renal artery clamping. Three calves underwent a total of 5 main renal artery occlusions. All animals, except the first pig and calf, underwent partial nephrectomy. Four partial nephrectomies were performed in an open fashion and four were performed laparoscopically. Duration of selective ischemia was recorded and location of vascular occlusion was noted both angiographically and visually. All resection sites were closed over a hemostatic bolster. Polymer reversal from a solid back to a liquid state with iced saline allowing reperfusion was evaluated. Following surgery, all animals were euthanized. RESULTS Selective renal ischemia was achieved in all cases using Lumagel™. Hemostasis was achieved for 30 minutes in all main and segmental renal artery occlusions. Surgical resection time averaged 11 minutes (range 10–13) and 23.3 (range 9–40) in the open and laparoscopic groups, respectively. Estimated blood loss was negligible with the exception of one case where an insufficient dose of polymer was used. Minimal venous back bleeding was noted with isolated main renal artery occlusion. Reversal of the polymer to a liquid state was consistent angiographically and visually in all ten cases. Time to complete flow return averaged 7 and 2.5 minutes for Lumagel™ and arterial clamping, respectively. CONCLUSIONS We have developed a reliable and reproducible technique for the delivery and dissolution of Lumagel™ for temporary vascular occlusion in both main and segmental renal arteries, ranging from 2 to 8mm in diameter. Lumagel™ is as effective as vascular clamping in producing a bloodless operative field. Time to complete flow return to the kidney is greater with Lumagel™. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 185Issue 4SApril 2011Page: e487 Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Niall Harty Burlington, MA More articles by this author Spencer Kozinn Burlington, MA More articles by this author Jessica DeLong Burlington, MA More articles by this author Ali Moinzadeh Burlington, MA More articles by this author Sebastian Flacke Burlington, MA More articles by this author James Benn Woburn, MA More articles by this author John Libertino Burlington, MA More articles by this author Peter Madras Burlington, MA More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Fixture Design Based on Magneto-Rheological Fluids for Thin Wall Spherical Shell Precision Machining

Thin wall spherical shell is easy to deform at the process of turning because the low rigidity. In order to improve process precision of the thin wall spherical shell, the thought increasing the workpiece technology stiffness is put forward, which the magneto-rheological fluids (MRF) is filled inside the thin wall spherical shells as strengthening phase transition material. In magnetic field, MRF can transform from fluid to solid and solid back to fluid rapidly. According to the thought, the fixture designed is applicable for the thin wall spherical shells process precision. The clamp stiffness can be controlled and the MRF can be used many times. In order to get uniform intensity of the magnetic field in MRF, the special magnetic device is designed which is based on the variable MRF thickness and the magnetic field distributing is analyzed and optimized. The fixture based on MRF will help to improve machining precision of the thin wall spherical shells.