DETERMINATION OF OPTIMUM SELECTIVE FLOTATION CONDITIONS OF KOYULHISAR Pb-Cu-Zn ORE BY GUM ARABIC

Bu çalıĞ¢mada, Sivas-Koyulhisar yöresinden temin edilen Pb-Cu-Zn kompleks cevherinin gang bastırıcı olarak Gum Arabic kullanılarak selektif flotasyonla zenginleĞ¢tirilmesinde optimum flotasyon koĞ¢ulları belirlenmeye çalıĞ¢ılmıĞ¢tır. Deneylerde kullanılan Koyulhisar Pb-Cu-Zn kompleks cevherinin %6.54 Pb, %1.45 Cu ve %7.47 Zn tenörlü olduğu kimyasal analiz ile tespit edilmiĞ¢tir. Selektif flotasyonun ilk kademesinde Pb, ikinci kademesinde Cu ve üçüncü kademesinde ise Zn kaba konsantresi eldesinde en uygun flotasyon koĞ¢ulları belirlenmiĞ¢tir. Elde edilen kaba konsantreler daha sonra temizleme flotasyonlarına tabi tutulmuĞ¢tur. Selektif flotasyonla kazanılan Pb, Cu ve Zn kaba konsantrelerinin tenör değerleri sırasıyla; %24.33 Pb, %15.10 Cu ve %41.43 Zn, konsantre verim değerleri ise sırasıyla %93.45, %78.52 ve %89.57'dir. Deneyler sonucunda bu cevherin selektif flotasyonu için belirlenen optimum koĞ¢ullar: Pb kaba flotasyonu için; pH=8, 600 gr/ton Gum Arabic, 40 gr/ton NaCN, 600 gr/ton ZnSO4, 120 gr/ton KAX, 90 gr/ton 2 Etil Hekzanol, köpük alma süresi 5 dakika, Cu kaba flotasyonu için; pH=8, 400 gr/ton Gum Arabic, 20 gr/ton NaCN, 800 gr/ton ZnSO4, 100 gr/ton Na2Cr2O7, 60 gr/ton KAX, 40 gr/ton 2 Etil Hekzanol, köpük alma süresi 5 dakika, Zn kaba flotasyonu için; pH=11, 400 gr/ton Gum Arabic, 60 gr/ton NaCN, 80 gr/ton Na2Cr2O7, 250 gr/ton CuSO4, 100 gr/ton KAX, 90 gr/ton 2 Etil Hekzanol, köpük alma süresi 5 dakika, olarak bulunmuĞ¢tur. Kaba konsantrelerin temizleme flotasyonuna tabi tutulmasıyla elde edilen Pb, Cu ve Zn nihai konsantrelerinin tenörleri sırasıyla; %69.26 Pb, %29.52 Cu ve %58.14 Zn, konsantre verim değerleri ise %72.33, %66.16 ve %75.65'dir. In this study, optimum flotation conditions for Koyulhisar Pb-Cu-Zn ore was determined using by Gum Arabic as depressant. Ore sample's grade is 6.54% Pb, 1.45% Cu and 7.47% Zn from chemical analysis. The most suitable conditions were fixed for Pb, Cu, and Zn rough flotation in first, second and third stage respectively and cleaning experiments were carried out for each of these concentrates. The grade of Pb, Cu and Zn rough concentrates are 24.33% Pb, 15.10% Cu and 41.43% Zn were obtained with recoveries 93.45%, 78.52% and 89.57% respectively. The optimum conditions for selective flotation are below: Pb rough flotation: pH=8, 600 gr/ton Gum Arabic, 40 gr/ton NaCN, 600 gr/ton ZnSO4, 120 gr/ton KAX, 90 gr/ton 2 Etil Hekzanol, flotation time 5 min. Cu rough flotation: pH=8, 400 gr/ton Gum Arabic, 20 gr/ton NaCN, 800 gr/ton ZnSO4, 100 gr/ton Na2Cr2O7, 60 gr/ton KAX, 40 gr/ton 2 Etil Hekzanol, flotation time 5 min. Zn rough flotation: pH=11, 400 gr/ton Gum Arabic, 60 gr/ton NaCN, 80 gr/ton Na2Cr2O7, 250 gr/ton CuSO4, 100 gr/ton KAX, 90 gr/ton 2 Etil Hekzanol, flotation time 5 min. The grades of concentrates after cleaning flotation 69.26% Pb, 29.52% Cu and 58.14% Zn were obtained with recoveries 72.33%, 66.16% and 75.65% respectively

Constraining spacetime torsion with LAGEOS

We compute the corrections to the orbital Lense-Thirring effect (or frame-dragging) in the presence of spacetime torsion. We derive the equations of motion of a test body in the gravitational field of a rotating axisymmetric massive body, using the parametrized framework of Mao, Tegmark, Guth and Cabi. We calculate the secular variations of the longitudes of the node and of the pericenter. We also show how the LAser GEOdynamics Satellites (LAGEOS) can be used to constrain torsion parameters. We report the experimental constraints obtained using both the nodes and perigee measurements of the orbital Lense-Thirring effect. This makes LAGEOS and Gravity Probe B (GPB) complementary frame-dragging and torsion experiments, since they constrain three different combinations of torsion parameters

An ordinary differential equation for velocity distribution and dip-phenomenon in open channel flows

An ordinary differential equation for velocity distribution in open channel flows is presented based on an analysis of the Reynolds-Averaged Navier-Stokes equations and a log-wake modified eddy viscosity distribution. This proposed equation allows to predict the velocity-dip-phenomenon, i.e. the maximum velocity below the free surface. Two different degrees of approximations are presented, a semi-analytical solution of the proposed ordinary differential equation, i.e. the full dip-modified-log-wake law and a simple dip-modified-log-wake law. Velocity profiles of the two laws and the numerical solution of the ordinary differential equation are compared with experimental data. This study shows that the dip correction is not efficient for a small Coles' parameter, accurate predictions require larger values. The simple dip-modified-log-wake law shows reasonable agreement and seems to be an interesting tool of intermediate accuracy. The full dip-modified-log-wake law, with a parameter for dip-correction obtained from an estimation of dip positions, provides accurate velocity profiles

Spondyloenchondrodysplasia Due to Mutations in ACP5: A Comprehensive Survey

Purpose: Spondyloenchondrodysplasia is a rare immuno-osseous dysplasia caused by biallelic mutations in ACP5. We aimed to provide a survey of the skeletal, neurological and immune manifestations of this disease in a cohort of molecularly confirmed cases. Methods: We compiled clinical, genetic and serological data from a total of 26 patients from 18 pedigrees, all with biallelic ACP5 mutations. Results: We observed a variability in skeletal, neurological and immune phenotypes, which was sometimes marked even between affected siblings. In total, 22 of 26 patients manifested autoimmune disease, most frequently autoimmune thrombocytopenia and systemic lupus erythematosus. Four patients were considered to demonstrate no clinical autoimmune disease, although two were positive for autoantibodies. In the majority of patients tested we detected upregulated expression of interferon-stimulated genes (ISGs), in keeping with the autoimmune phenotype and the likely immune-regulatory function of the deficient protein tartrate resistant acid phosphatase (TRAP). Two mutation positive patients did not demonstrate an upregulation of ISGs, including one patient with significant autoimmune disease controlled by immunosuppressive therapy. Conclusions: Our data expand the known phenotype of SPENCD. We propose that the OMIM differentiation between spondyloenchondrodysplasia and spondyloenchondrodysplasia with immune dysregulation is no longer appropriate, since the molecular evidence that we provide suggests that these phenotypes represent a continuum of the same disorder. In addition, the absence of an interferon signature following immunomodulatory treatments in a patient with significant autoimmune disease may indicate a therapeutic response important for the immune manifestations of spondyloenchondrodysplasia

Streamwise-travelling viscous waves in channel flows

The unsteady viscous flow induced by streamwise-travelling waves of spanwise wall velocity in an incompressible laminar channel flow is investigated. Wall waves belonging to this category have found important practical applications, such as microfluidic flow manipulation via electro-osmosis and surface acoustic forcing and reduction of wall friction in turbulent wall-bounded flows. An analytical solution composed of the classical streamwise Poiseuille flow and a spanwise velocity profile described by the parabolic cylinder function is found. The solution depends on the bulk Reynolds number R, the scaled streamwise wavelength (Formula presented.), and the scaled wave phase speed U. Numerical solutions are discussed for various combinations of these parameters. The flow is studied by the boundary-layer theory, thereby revealing the dominant physical balances and quantifying the thickness of the near-wall spanwise flow. The Wentzel–Kramers–Brillouin–Jeffreys (WKBJ) theory is also employed to obtain an analytical solution, which is valid across the whole channel. For positive wave speeds which are smaller than or equal to the maximum streamwise velocity, a turning-point behaviour emerges through the WKBJ analysis. Between the wall and the turning point, the wall-normal viscous effects are balanced solely by the convection driven by the wall forcing, while between the turning point and the centreline, the Poiseuille convection balances the wall-normal diffusion. At the turning point, the Poiseuille convection and the convection from the wall forcing cancel each other out, which leads to a constant viscous stress and to the break down of the WKBJ solution. This flow regime is analysed through a WKBJ composite expansion and the Langer method. The Langer solution is simpler and more accurate than the WKBJ composite solution, while the latter quantifies the thickness of the turning-point region. We also discuss how these waves can be generated via surface acoustic forcing and electro-osmosis and propose their use as microfluidic flow mixing devices. For the electro-osmosis case, the Helmholtz–Smoluchowski velocity at the edge of the Debye–Hückel layer, which drives the bulk electrically neutral flow, is obtained by matched asymptotic expansion