The effects of hydrological factors on river suspended solids contamination from a colliery in South Wales

Suspended solids contamination caused by runoff below a working colliery in the Upper Clydach catchment in South Wales, U.K., was investigated in relation to hydrological controls. Field studies over a 16 month period found that concentrations below the colliery ranged from 4 to 8028 mg 1^?1. Simple correlation and linear regression analysis of spot and storm event samples taken below the colliery gave a correlation coefficient of 0·39 between flow and suspended solids concentration. Because of the lack of explained variance, a multiple linear regression model of within-storm concentrations was derived using four selected independent variables. X₁ the time relation of the sample to the storm peak; log X₂ the stormflow at the time of sampling; log X₃ the baseflow at the time of sampling; and log X₄ an index of the storm intensity. Analysis of the entire dataset gave an R² of 0·34. When the results from three atypical events were excluded however, the R² value improved to 0·65. Beta coefficients indicated that rising limb conditions (X₁) and intense storms (log X₄) along with dry antecedent conditions (log X₃) represent the worst combination of hydrological factors for producing suspended solids contamination.     

Singlet oxygen O2(b1Σ g + ) production at altitudes of the polar ionosphere

The relative rate constants of O₂(b¹Σ _g ⁺ , v= 1–4) production at an inelastic interaction between electronically excited N(²D) atoms and O₂(X³Σ _g ^? , v = 0) oxygen molecules have been calculated. It was shown that an increase in equilibrium distances between oxygen atoms in NO₂ quasi-molecule, produced during the interaction, substantially increases the calculated relative production rates of O₂(b¹Σ _g ⁺ , v > 1). The obtained coefficients are used to calculate the O₂(b¹Σ _g ⁺ , v= 1–4) relative populations at 110 km (T = 250 K) and 150 km (T = 500 K) altitudes of the polar ionosphere. The calculated populations have been compared with the results of the published measurements of the Atmospheric system band luminosity intensities, and satisfactory agreement has been obtained for low altitudes.     

An examination of τc-Pd earthquake early warning method using a strong-motion building array

The use of characteristic period τ_c and peak displacement amplitude Pd of the initial P wave in earthquake early warning (EEW) was proposed by Wu and Kanamori 1, 2, 3 and 4. Here we apply this approach to strong-motion records from a building sensor array installed in Taitung County, Taiwan. This building was damaged during the 2006 M_w=6.1 Taitung earthquake with a peak ground velocity (PGV) of up to 38.4 cm/s at an epicentral distance of 14.5 km. According to our analysis, the peak displacement amplitude Pd is a better indicator for the destructiveness of an earthquake than τ_c because τ_c is more sensitive to the signal-to-noise ratio (SNR) than Pd. In accordance with previous studies, only the structurally damaging Taitung earthquake generated a Pd value larger than 0.5 cm (a threshold for identifying damaging events). Using Pd as an indicator for destructive earthquakes does not lead to missing or false alarms for EEW purposes.     

Improved method to determine the molar volume and compositions of the NaCl-H<Subscript>2</Subscript>O-CO<Subscript>2</Subscript> system inclusion

On the basis of Parry’s method (1986), an improved method was established to determine the molar volume (Vm) and compositions (X) of the NaCl-H2O-CO2 (NHC) system inclusion. To use this method, the determination of Vm-X only requires three microthermometric data of a NHC inclusion: partial homog-enization temperature (Th ,CO2), salinity (S) and total homogenization temperature (Th). Theoretically, four associated equations are needed containing four unknown parameters: X CO2, XNaCl, Vm and F (volume fraction of CO2 phase in total inclusion when occurring partial homogenization). When they are released, the Vm-X are determined. The former three equations, only correlated with Th ,CO2, S and F, have simplified expressions:XCO2=f1(Th,CO2,S,F),XNaCl=f2(Th,CO2,S,F),Vm=f3(Th,CO2,S,F). The last one is the thermodynamic relationship of X CO2, XNaCl, Vm and Th:f4(XCO2,XNaCl,Vm,Th)=0.Since the above four associated equations are complicated, it is necessary to adopt iterative technique to release them. The technique can be described by:(i) Freely input a F value (0≤F≤1),with Th ,CO2 and S, into the former three equations. As a result,X CO 2,XNaCl and the molar volume value recorded as Vm1 are derived. (ii) Input the X CO2 and XNaCl gotten in the step above into the last equation, and another molar volume value recorded as Vm2 is determined. (iii) If Vm1 is unequal to Vm2, the calculation will be restarted from “(i)”. The iteration is completed until Vm1 is equal to Vm2, which means that the four associated equations are released. Compared to Parry’s (1986) solution method, the improved method is more convenient to use, as well as more accurate to determine X CO 2. It is available for a NHC inlusion whose partial homogenization temperature is higher than clatherate melting temperature and there are no solid salt crystals in the inclusion at parital homogenization.     

Ni2SiO4-enthalphy of the olivine-spinel transition by solution calorimetry at 713°C

The high pressure spinel polymorph of Ni₂SiO₄ persists metastably at 713°C and atmospheric pressure. The enthalpy of the olivine-spinel transition was obtained by measuring the heats of solution of both polymorphs in a molten oxide solvent, 2PbO · B₂O₃, at that temperature. For Ni₂SiO₄(ol)→Ni₂SiO₄, ΔH₉₈₆⁰ = +1.4 ± 0.7kcal/mol. The heat content increments, H₉₈₆ ? H₂₉₇, were found to be: olivine, 25.73 ± 0.42kcal/mol, and spinel, 25.39 ± 0.20kcal/mol. The measured enthalpy of the transformation is consistent with the low slope of the phase boundary, ?P/?T = ～ 12b/deg, observed by Akimoto and others. The entropy of the olivine-spinel transition in Ni₂SiO₄ is accordingly about a factor of three smaller in magnitude (ΔS = ～ ?1cal/deg mol) than that for Co₂SiO₄,Fe₂SiO₄,Mg₂SiO₄or Mg₂GeO₄ (ΔS = ?3to?3.5cal/deg mol).     

Derivation of bivariate probability density functions with exponential marginals

A vivariate probability density function (pdf),f(x ₁,x ₂), admissible for two random variables (X ₁,X ₂), is of the form

A multivariate gamma distribution arising from a Markov model

A Markov chain{X _t }, which has been useful for modelling in hydrology, can be specified by the Laplace transform (LT) of the conditional p.d.f. ofX _t+1 givenX _t =x _t , which is assumed to be of the exponential formH()exp{-G()x _t }. For appropriate choice ofH andG the marginal distribution ofX _t is the (univariate) gamma distribution. In this case, the joint p.d.f. ofX _t +1,...,X _t+n and its LT, are obtained, and this is extended to a seasonal version of the chain. A simple method of generating observations from these multivariate gamma distributions is noted, and the joint LT is applied to the problem of determining moments of weighted sums of such variables.     

Petrology and phase equilibrium of newly found eclogites from Kekesu Valley in eastern part of southwest Tianshan HP-UHP metamorphic belt, China, and its tectonic significance

Eclogites and omphacite-bearing blueschists have been newly found in the eastern segment of the southwest Tianshan orogenic belt,Xinjiang,northwest China.After detailed petrological study,three samples including one fresh eclogite TK003,one blueschist sample TK026-8 and one retrograded eclogite TK027,were selected for phase equilibrium modeling under NC(K)MnFMASHO(N2O-CaO-K2O-MnO-FeO-MgO-Al2O3-SiO2-H2O-O)system,by thermocalc 3.33 software.Composition analyses of garnets in these three samples show typical growth zoning with Xpy and Xgrs increasing,Xspss decreasing from core to rim.Pseudosection modeling of the garnet zonation reflects that the eclogites and blueschist experienced a similar P-T evolution trajectory,with a near iso-baric heating in the early stage,and reached eclogite facies metamorphic field with peak P-T regime of 480–515°C,2.00–2.30 GPa.Subsequently the rocks experienced an early iso-thermal decompression retrograde stage with P-T conditions of 515–519°C,1.78–1.93 GPa.Variations of mineralogy and modes of these rocks are probably due to different retrograde paths as a consequence of different bulk-rock composition,as well as a variation in fluid activity during exhumation.P-T calculation and a peak geothermal gradient of 6–7°C/km indicate HP rocks in the Kekesu Valley experienced cold subducted eclogite facies metamorphism.Thus a huge oceanic subduction eclogite facies metamorphic belt in southwest Tianshan has been recognized,extending from the Kekesu Valley in the east to the Muzhaerte Valley in the west for nearly200 km.However,UHP evidence has not been found in the Kekesu terrane,perhaps because the slab in east part of southwest Tianshan did not subduct into such a great depth.     

Photochemistry of Ions at D-region Altitudes of the Ionosphere: A Review

The current state of knowledge of the D-region ion photochemistry is reviewed. Equations determining production rates of electrons and positive ions by photoionization of atmospheric neutral species are presented and briefly discussed. Considerable attention is given to the progress in the chemistry of O⁺(⁴S), O⁺(²D), O⁺(²P), N⁺, N₂ ⁺, O₂ ⁺, NO⁺, N₄ ⁺, O₄ ⁺, NO⁺(N₂), NO⁺(CO₂), NO⁺(CO₂)₂, NO⁺(H₂O) _n for n = 1–3, NO⁺(H₂O)(N₂), NO⁺(H₂O)₂(N₂), NO⁺(H₂O)(CO₂), NO⁺(H₂O)₂(CO₂), O₂ ⁺(H₂O), H₃O⁺(OH), H⁺(H₂O) _n for n = 1–8, O^?, O₂ ^?, O₃ ^?, O₄ ^?, OH^?, CO₃ ^?, CO₄ ^?, NO₂ ^?, NO₃ ^?, ONOO^?, Cl^?, Cl^?(H₂O), Cl^?(CO₂), HCO₃ ^?, CO₃ ^?(H₂O), CO₃ ^?(H₂O)₂, NO₃ ^?(H₂O), NO₃ ^?(H₂O)₂, OH^?(H₂O), and OH^?(H₂O)₂ ions. The analysis of the D-region rocket ion mass spectrometer measurements shows that, among these ions, O₂ ⁺, NO⁺, NO⁺(H₂O), and H⁺(H₂O) _n for n = 1–7 can make the main contribution to the total positive ion number density, and O^?, O₂ ^?, Cl^?, OH^?(H₂O), CO₃ ^?, HCO₃ ^?, NO₃ ^?, ONOO^?, CO₄ ^?, NO₃ ^?(H₂O), NO₃ ^?(H₂O)₂, and ³⁵Cl^?(CO₂) ions can be responsible for the main contribution to the total negative ion number density. Photodetachment of electrons from O^?, Cl^?, O₂ ^?, O₃ ^?, OH^?, NO₂ ^?, and NO₃ ^?, dissociative electron photodetachment of O₄ ^? and OH^?(H₂O), and photodissociation of O₃ ^?, O₄ ^?, CO₃ ^?, CO₄ ^?, ONOO^?, HCO₃ ^?, CO₃ ^?(H₂O), NO₃ ^?(H₂O), O₂ ⁺(H₂O), O₄ ⁺, N₄ ⁺, NO⁺(H₂O), NO⁺(H₂O)₂, H⁺(H₂O) _n for n = 2–4, NO⁺(N₂), and NO⁺(CO₂) are studied, and the photodetachment and photodissociation rate coefficients are calculated using the current state of knowledge on the cross sections of these processes and fluxes of solar radiation.     

A new methodology to determine elastic displacement spectra in the near-fault region

The evaluation of the displacement demand especially at small distances from the causative fault, in the so-called near-source region, is a subject of particular interest for earthquake engineering design, in the light of the growing application of the displacement-based design philosophy. This study presents a new methodology to determine the elastic displacement spectra using a sample of near-fault records from small-to-moderate magnitude earthquakes, typical of the seismic activity in Europe. The displacement spectrum is developed using near-fault attenuation relationships available in literature for peak ground velocity that is less sensitive in the procedures applied to correct the accelerograms. Also, the distance from the causative fault and the type of directivity are taken into consideration. The prevailing period corresponds to the maxima of the displacement spectra for zero damping and is used to normalize the spectra, leading to significant decrease of the statistical dispersion. The average bi-normalized spectrum, in terms of the peak ground displacement d_g,max and the dominant period T_d-p, appears to be slightly affected by the soil category and earthquake magnitude. A correlation between the damping correction factor η and the normalized period T/T_d-p is detected and the applicability of several provisions of the current version of Eurocode 8 is examined, including characteristic periods and spectral amplitudes.     

A Study of the Relationships between the Characteristic Acceleration Frequencies and Earthquake Magnitude: The Baikal Rift Zone

This study is concerned with characteristic frequencies of acceleration spectra as functions of the moment magnitude М _w for crustal earthquakes in the 3 ≤ М _w ≤ 6.4 range that have occurred in the Baikal Rift Zone (BRZ). The characteristic frequencies were defined as those at which maxima occur in the spectra: f_Sm, f₁, and f₂, at the 0.7S_m and 0.5S_m levels, as well as the f_c2 and f_c3 frequencies, which characterize the transition from the ascending branch of the spectrum (f_c2) to the gently sloping branch, and the f_c3 frequency, which shows the transition from the gently sloping part to the descending branch. All the characteristic frequencies move toward lower values with increasing earthquake magnitude. The resulting relationships for f_c2 and f_c3 were used to estimate the scaling, with the result that no similarity is present. As well, we have found no wellpronounced differences in earthquake spectra between different focal mechanism events. It was found that the slope of the low-frequency branch decreases and the high-frequency descending branch becomes flattened with increasing magnitude.     

Oxysulfates of copper, sodium, and potassium in the lava flows of the 2012–2013 Tolbachik Fissure Eruption

Samples from the surface of lava flows discharged by the 2012–2013 Tolbachik Fissure Eruption were found to contain oxysulfates of copper, sodium, and potassium: K₂Cu₃O(SO₄)₂ (fedotovite), NaKCu₂O(SO₄)₂, and Na₃K₅Cu₈O₄(SO₄)₈. The last two phases have no naturally occurring or synthetic analogues that we are aware of. They form flattened crystals of prismatic to long-prismatic habits. The crystals of Na₃K₅Cu₈O₄(SO₄)₈ have a chemical composition corresponding to the empirical formula Na_2.22K_5.47Cu_8.02S_8.05O₃₆. An X-ray analysis of this compound showed that it has a monoclinic symmetry, P2/c, a = 13.909(4), b = 4.977(1), c = 23.525(6) Å, β = 90.021(5)°, V = 1628.3(7) ų. The crystal structure was determined by direct techniques and refined to yield R ₁ for 3955 reflexes//web// with F ² > 4σF. The compound NaKCu₂O(SO₄)₂ also belongs to the monoclinic system, P2/c, a = 14.111(4), b = 4.946(1), c = 23.673(6) Å, β = 92.052(6)°, V = 1651.1(8) ų. The structure was determined by direct techniques to yield a tentative structural model that has been refined up to R ₁ = 0.135 for 4088 reflexes with F ² > 4σF. The crystal structure of Na₃K₅Cu₈O₄(SO₄)₈ is based on chains of [O₂Cu₄]⁴⁺ consisting of rib-coupled oxy-centered tetrahedrons of (OCu₄)⁶⁺. The chains are surrounded by sulfate radicals, resulting in columns of {[O₂Cu₄](SO₄)₄}^4? aligned along the b axis. The interchain space contains completely ordered positions of Na⁺ and K⁺ cations. The principle underlying the connection of NaKCu₂O(SO₄)₂ columns in the crystal structure of {[O₂Cu₄](SO₄)₄}^4? is different, in view of the relation Na:K = 1 as contrasted with 3:5 for the compound Na₃K₅Cu₈O₄(SO₄)₈. The presence of oxy-centered tetrahedrons in the structure of these new compounds furnishes an indirect hint at the importance of polynuclear copper-oxygen radicals with centering oxygen atoms as forms of transport of copper by volcanic gases.     

Retrospective Study on the Predictability of Pattern Informatics to the Wenchuan M8.0 and Yutian M7.3 Earthquakes

Two large earthquakes occurred in the western part of China in 2008, one of them being the Yutian (35.6°N, 81.6°E) M7.3 earthquake that occurred on March 21 (BJT) and the other the Wenchuan (31.0°N, 103.4°E) M8.0 earthquake that occurred on May 12 (BJT). In this paper, the West Continental China (included in 20.0°–50.0°N, 70.0°–110.0°E region) was the study region for verifyong the predictability of the pattern informatics (PI) method using the receiver-operating characteristic curve (ROC) test and R score test. Different forecasting maps with different calculating parameters were obtained. The calculating parameters were the grid size Δx, base time t _b, reference interval t _b to t ₁, change interval t ₁ to t ₂, and forecasting interval t ₂ to t ₃. In this paper, the base time t _b fixed to June 1, 1971, the ending forecast time t ₃ fixed to June 1, 2008, and the forecasting interval t ₂ to t ₃ changed from 1 to 10 years, and the grid sizes were chosen as 1° × 1° and 2° × 2°, respectively. The results show that the PI method could forecast the Yutian M7.3 and Wenchuan M8.0 earthquakes only using suitable parameters. Comparing the forecast results of grid sizes 1° × 1° and 2° × 2°, the models with 2° × 2° grids were better. Comparing the forecast results with different forecasting windows from 1 to 10 years, the models with forecasting windows of 4–8 years were better using the ROC test, and the models with forecasting windows of 7–10 years were better using the R score test. The forecast efficiency of the model with a grid size of 2° × 2° and forecast window of 8 years was the best one using either the ROC test or the R score test.     

A bivariate analysis of the volume and duration of low-flow events

: The knowledge of the volume and duration of low-flow events in river channels is essential for water management and the design of hydraulics structures. In this study, both preceding characteristics, X ₁ and X ₂, are considered simultaneously via two types of bivariate distributions whose marginals are exponential. One of these bivariate distributions has been presented by Nagao and Kadoya (1971) and the other has been used by Singh and Singh (1991) to the study of rainfall intensity and rainfall depth. The results are applied to the low-flow series (“peaks-below-threshold”) of Lepreau River (station 01AQ001) in New Brunswick, Canada. These results show that the model that was successfully employed by Singh and Singh (1991) to study rainfall, presents certain difficulties when a very strong correlation, ρ, between the two random variables X ₁ and X ₂, exists. The model by Nagao and Kadoya (1971) seems to be more satisfactory for such situations, although this model seems also to be quite sensitive to variations in ρ.     

A bivariate analysis of the volume and duration of low-flow events

: The knowledge of the volume and duration of low-flow events in river channels is essential for water management and the design of hydraulics structures. In this study, both preceding characteristics, X ₁ and X ₂, are considered simultaneously via two types of bivariate distributions whose marginals are exponential. One of these bivariate distributions has been presented by Nagao and Kadoya (1971) and the other has been used by Singh and Singh (1991) to the study of rainfall intensity and rainfall depth. The results are applied to the low-flow series (“peaks-below-threshold”) of Lepreau River (station 01AQ001) in New Brunswick, Canada. These results show that the model that was successfully employed by Singh and Singh (1991) to study rainfall, presents certain difficulties when a very strong correlation, ρ, between the two random variables X ₁ and X ₂, exists. The model by Nagao and Kadoya (1971) seems to be more satisfactory for such situations, although this model seems also to be quite sensitive to variations in ρ.     

An event-based stochastic model of phosphorus loading into a lake

In most lakes, phosphorus (P) is the nutrient controlling the trophic state. Thus, for effective control of eutrophication, the uncertainty in P-loading should be encoded as a probability density function (pdf). Specifically, the pdf of P-loading Y from non-point agricultural sources is sought by means of an event-based stochastic model.P-loading events are triggered by precipitation events (X₁, X₂, T), in which X₁ is the rainfall amount, X₂ the duration, and T the interarrival time between events. (X₁, X₂) are dependent random variables, while T is assumed to be exponentially distributed. The precipitation event causes runoff, which carries dissolved P into the lake with a concentration C₁ and sediment yield, Z, which carries fixed or sorbed P into the lake in a fraction C₂ of Z. Seasonal loading of P is calculated by adding random numbers of random variables. The model accounts separately for dissolved P and sorbed P. Explicit expressions are given for the mean and variance of each type of P-loadings. The case study of a sub-watershed of Lake Balaton, Hungary, is used to illustrate the methodology. Precipitation data, empirical rainfall-runoff-sediment yield relationships and a small number of observations of events are used to calibrate the model and estimate the means and variances of loading per event and per season. Then a simulation method is used to estimate complete pdf of these random variables. Use of the model for alternative methods of controlling P-loading is briefly discussed, as well as the economics of control.     

Estimations of the uncertainty in timing the relationship between magnetospheric and solar wind processes

We present here a statistical study quantifying the errors associated with the most commonly used methods for propagating discontinuities in the interplanetary magnetic field (IMF) from an upstream monitor to the magnetosphere by the magnetospheric and ionospheric communities. The purpose of this paper is to show the quantified errors in the different techniques. Step changes in the IMF orientation were first identified at the WIND satellite. A total of 363 events were identified. Ninety percent of the events measured at WIND (330) were clearly observed in the IMP 8 data. Of those events, the time delay between the satellites could be determined to within 2 min in 288 events. Four propagation methods were used to estimate the time delay between WIND and IMP 8: (1) using only the X distance between the satellites; (2) assuming that the propagation front plane is in the plane of the Parker spiral; (3) using the IMF in the X–Y plane to estimate the propagation front plane; and (4) using the total IMF to determine the Z component of the propagation front plane. The average (Ē) and maximum (E_max) propagation error (in minutes) as a function of Y–Z distance (in R_e) were determined for each method. It is concluded that the average uncertainty in propagation is 7.5–8.5 min for off-axis distances of 30 R_e (which is the average WIND off-axis distance, and approximately the largest off-axis distance of IMP 8). For off-axis distances of 100 R_e (the largest off-axis distance of WIND), the uncertainties are 17.5–25 min, depending on the propagation method.     

Absolute18O content of standard mean ocean water

The absolute values of the¹⁸O/¹⁶O ratio (R_s) and the relative¹⁸O content (X_s) in SMOW have been determined by comparing SMOW mass spectrometrically with well-defined synthetic mixtures of pure D₂¹⁸O and H₂¹⁶O. The results are:R_S = (2005.20 ± 0.45) × 10^?6, X_S = (2000.45 ± 0.45) × 10^?6     

Conditioned ranges for independent symmetric three valued inflows

The paper considers, as inputs to a storage system, independent random variablesX ₁,X ₂,... which have a symmetric three-valued distribution. Expressions are obtained for the conditional expected values of (i) the adjusted range ofX ₁,...X _n, conditioned on the eventX ₁+...+X _n=0; (ii) the Hurst range ofX ₁,...,X _n , conditioned on essentially the same event. Numerical comparisons of these two conditioned ranges show that they are close in value unless the inputs have high kurtosis.     

Magnetic properties of synthetic titanomagnetites

Magnetic properties and crystal structure parameters of synthetic solid solutions Fe₃O₄Fe₃TiO₄, Fe₂O₄MgFe₂O₄ and Fe₃O₄Mg₂TiO₄ have been studied. Basic regularities in the behaviour of saturation magnetisation (I_s), Curie temperature (T_C) and cubic lattice parameter a during the substitution of Ti and Mg ions for Fe ions have been found. As the concentration of Ti ions increases, I_s reduces from 70 Gs·cm³ g^?1 to 0, T_C changes from 580 to 130°C and a from 8.391 to 8.520 Å. Growth of the Mg concentration leads to changes in I_s to 19.8 Gs·cm³, g^?1, T_C, to 440°C and a, to 8.360 Å. The full Fe ions substitution gives $\text{“a”=8.440}\text{A}\text{?}$.Chemical compositions of the samples, in which the valency variation of Fe ions at oxidation leads to an increase in susceptibility and T_C, have been determined.