Geochemistry in the mid Atlantic Ocean ridge basalts

The main objective of Leg 82 of the Glomar Challenger was to document mantle heterogeneity in the vicinity of, and away from, a so-called hot spot: the Azores Triple Junction. One of the geochemical tools that permits, at least in part, the recognition of mantle heterogeneities uses hygromagmaphile elements, those elements that have an affinity for the liquid. This tool is presented in terms of an extended Coryell-Masuda plot, which incorporates within the rare earth elements the hygromagmaphile transition elements Th, Ta, Zr, Hf, Ti, Y, and V. The extended Coryell-Masuda plot is used to summarize our knowledge of mantle heterogeneity along the ridge axis at zero-age. It is also used by choosing those hygromagmaphile elements that can be analyzed on board by X-ray fluorescence spectrometry to give preliminary information on the enriched or depleted character of recovered samples. Shore-based results, which include analyses of most of the hygromagmaphile elements measured either by X-ray spectrometry or neutron activation analysis, confirm the shipboard data. From the point of view of comparative geochemistry, the variety of basalts recovered during Leg 82 provides a good opportunity to test and verify the classification of the hygromagmaphile elements. Analyses from Leg 82 provide new data about the relationship between extended rare earth patterns (enriched or depleted) that can be estimated either by La/Sm ratio or Nb/Zr (or Ta/Hf) ratios: samples from Hole 556 are depleted (low Nb/Zr ratio) but have a high 206Pb/ 204Pb (19.5) ratio; in Hole 558 a moderately enriched basalt unit with a La/Sm (= Nb/Zr) ratio (chondrite normalized) of 2 has a high 206Pb/204Pb (20) ratio. One of the most interesting results of Leg 82 lies in the crossing patterns of extended Coryell-Masuda plots for basalts from the same hole. This result enhances the notion of local mantle heterogeneity versus regional mantle heterogeneity and is confirmed by isotope data; it also favors a model of short-lived, discrete magma chambers. The data tend to confirm the Hayes Fracture Zone as a southern limit for the influence of Azores-type mantle. Nevertheless, north of the Hayes Fracture Zone, the influence of a plumelike mantle source is not simple and probably requires an explanation more complex than a contribution from a single fixed hot spot.

Geochemistry of ODP Leg 135 igneous rock samples

Ocean Drilling Program Leg 135 provided igneous rock cores from six sites drilled on a transect across the Lau Basin between the Lau Ridge remnant arc and the modem spreading ridges of the Central and Eastern Lau Spreading Centers. The drill cores sampled crust from the earliest stage of backarc extension (latest Miocene time, about 6 Ma), and younger crust (late Pliocene, about 3.8-2 Ma, and middle Pleistocene, about 0.64-0.8 Ma). Nearly all of the igneous samples are from tholeiitic basalt flows; many of them are interbedded with arc-composition volcaniclastic sediments. Rock compositions range from olivine-plagioclase-clinopyroxene basalt, with up to 8% MgO, to oceanic andesites with less than 3.2% MgO and silica contents as high as 56%. The oldest rocks recovered are close in composition to rocks formed at the modern Central and Eastern Lau Spreading Centers and have MORB-like characteristics. Generation of the oldest units was coeval with arc-tholeiitic volcanism on the Lau Ridge less than 100 km to the west. The arc and backarc melts came from different mantle sources. At three sites near the center of the basin, the crust is arc-tholeiitic basalt, two-pyroxene basaltic-andesite, and two-pyroxene andesite. These rocks have many similarities to modem Tofua Arc lavas yet they were drilled within 70 km of the MORB-like Eastern Lau Spreading Center. Estimates of the minimum age for these arc-like rocks indicate that they are late Pliocene (about 2 Ma). These ages overlap the age of the nearby Eastern Lau Spreading Center. The heterogeneous crust of the Lau Basin carries many of the signatures of supra-subduction zone (SSZ) melts but also has a distinct MORB-like component. Mixing between SSZ and MORB mantle sources may explain the variations and the spatial distribution of magma types.

Geochemistry of lower sheeted dike complex samples of ODP Holes 137-504B and 140-504B

Rocks of the lower sheeted dike complex of Hole 504B sampled during Leg 140 were analyzed for major and trace element compositions to investigate the effects of igneous processes and hydrothermal alteration on the compositions of the rocks. The rocks are relatively uniform in composition and similar to the shallower dikes. They are moderately evolved mid-ocean-ridge basalts (MORB) with relatively high MgO (7.9-10 wt%) and Mg# (0.60-0.70), and have unusually low incompatible element contents (TiO2 = 0.42-1.1 wt%, Zr = 23-62 ppm). Discrete compositional intervals in the hole reflect varying degrees of differentiation, and olivine and plagioclase accumulation in the rocks, and may be related to injection of packets of dikes having similar compositions. Systematic depletions of total REE, Zr, Y, TiO2, and P2O5 in centimeter-size patches are most likely attributed to exclusion of highly differentiated, late-stage interstitial liquids from small portions of the rocks. The rocks exhibit increased H2O+ reflecting hydrothermal alteration. Replacement of primary plagioclase by albite and oligoclase led to local gains of Na2O, losses of CaO, and slightly positive Eu anomalies. Some mobility of P2O5 led to minor increases and decreases in P2O5 contents, and some local mobility of Ti may have occurred during alteration of titanomagnetite to titanite. Higher temperatures of alteration in the lower sheeted dikes led to breakdown of pyroxene and sulfide minerals and losses of Zn, Cu, and S to hydrothermal fluids. Later addition of anhydrite to the rocks in microfractures and replacing plagioclase caused local increases in sulfur contents. The lower sheeted dikes are a major source of metals to hydrothermal fluids for the formation of metal sulfide deposits on and within the seafloor.

Microstructure and mechanical properties of Ti-15Zr alloy used as dental implant material

Ti-Zr alloys have recently started to receive a considerable amount of attention as promising materials for dental applications. This work compares mechanical properties of a new Ti-15Zr alloy to those of commercially pure titanium Grade4 in two surface conditions - machined and modified by sand-blasting and etching (SLA). As a result of significantly smaller grain size in the initial condition (1-2µm), the strength of Ti-15Zr alloy was found to be 10-15% higher than that of Grade4 titanium without reduction in the tensile elongation or compromising the fracture toughness. The fatigue endurance limit of the alloy was increased by around 30% (560MPa vs. 435MPa and 500MPa vs. 380MPa for machined and SLA-treated surfaces, respectively). Additional implant fatigue tests showed enhanced fatigue performance of Ti-15Zr over Ti-Grade4.

Geochemistry of meta-anorthosites from Holénarasipur, Karnataka, South India

Geochemical and Rb---Sr isotope studies indicate that the meta-anorthosites of Holénarasipur, occurring as minor differentiates in ultramafic-mafic complex are igneous intrusives with cumulus character, emplaced around 3095 m.y. ago. The fine-grained nature is secondary; relict cumulus features are preserved in less deformed bodies. In major element chemistry, they compare well with other Archean anorthosites. Abundance levels of Ti, Zr, Y and P indicate the evolution through crystal fractionation of a parental magma; cumulus olivine and pyroxenes dominated chemistry for ultramafites, cumulus plagioclase and possibly clinopyroxene controlled chemistry for anorthosite-gabbros and cumulus magnetite in magnetite-gabbros. Magnetite is not an early cumulate. REE geochemistry is dominated by plagioclase with low abundance levels, slightly LREE enriched and variable positive Eu anomaly. Sr and Image values vary with An content in plagioclase. Isotopic studies show low initial Image (=0.7016) indicating that Rb---Sr isochron age represents the time of intrusion rather than the time of metamorphism.

NO Reduction Over Noble Metal Ionic Catalysts

In last 40 years, catalysis for NO (x) removal from exhaust gas has received much attention to achieve pollution free environment. CeO(2) has been found to play a major role in the area of exhaust catalysis due to its unique redox properties. In last several years, we have been exploring an entirely new approach of dispersing noble metal ions in CeO(2) and TiO(2) for redox catalysis. We have extensively studied Ce(1-x) M (x) O(2-delta) (M = Pd, Pt, Rh), Ce(1-x-y) A (x) M (y) O(2-delta) (A = Ti, Zr, Sn, Fe; M = Pd, Pt) and Ti(1-x) M (x) O(2-delta) (M = Pd, Pt, Rh, Ru) catalysts for exhaust catalysis especially NO reduction and CO oxidation, structure-property relation and mechanism of catalytic reactions. In these catalysts, lower valent noble metal ion substitution in CeO(2) and TiO(2) creates noble metal ionic sites and oxide ion vacancy. NO gets molecularly adsorbed on noble metal ion site and dissociatively adsorbed on oxide ion vacancy site. Dissociative chemisorption of NO on oxide ion vacancy leads to preferential conversion of NO to N(2) instead of N(2)O over these catalysts. It has been demonstrated that these new generation noble metal ionic catalysts (NMIC) are much more catalytically active than conventional nano crystalline noble metal catalysts especially for NO reduction.

Nanostructured titanium-nickel alloys: a comparison of processing routes

Rapid solidification, mechanical alloying and devitrificaiton of precursor metallic glasses are all possible routes for the synthesis of nanocrystals and nanocomposites, though their efficacy is system dependent. In a comprehensive study of alloys across the Ti-Ni phase diagram, nanocrystals of Ti and Ni and nanocomposites of alpha -Ti and Ti sub 2 Ni, Ti sub 2 Ni and TiNi and beta -Ti and glass have been produced. By the addition of Al, devitrification of metallic glasses created by mechanical alloying led to nanocrystalline intermetallic compounds. The evolution of these nanocrystalline microstructures has been rationalized on the basis of thermodynamic and kinetic considerations involving the metastable phase diagram for this system.

EFFECT OF OFF-STOICHIOMETRY AND TERNARY ADDITIONS ON PLANAR FAULT ENERGIES IN Ni3Al

First principles calculations were done to evaluate the lattice parameter, cohesive energy and stacking fault energies of ordered gamma' (Ll(2)) precipitates in superalloys as a function of composition. It was found that addition of Ti and Ta lead to an increase in lattice parameter and decrease in cohesive energy, while Ni antisites had the opposite effect. Ta and Ti addition to stoichiometric Ni3Al resulted in an initial increase in the energies of APB((111)), CSF(111), APB((001)) and SISF(111). However, at higher concentrations, the fault energies decreased. Addition of Ni antisites decreased the energy of all four faults monotonically. A model based on nearest neighbor bonding was used for Ni-3(Al, Ta), Ni-3(Al, Ti) and Ni-3(Al, Ni) pseudo-binary systems and extended to pseudo- ternary Ni-3(Al, Ta, Ni) and Ni-3(Al, Ti, Ni) systems. Recipes were developed for predicting lattice parameters, cohesive energies and fault energies in pseudo- ternary systems on the basis of coefficients derived from simpler pseudobinary systems. The model predictions were found to be in good agreement with first principles calculations for lattice parameters, cohesive energies, and energies of APB((111)) and CSF(111).

Noble metal ion substituted CeO2 catalysts: Electronic interaction between noble metal ions and CeO2 lattice

In last 40 years, CeO2 has been found to play a major role in the area of auto exhaust catalysis due to its unique redox properties. Catalytic activity is enhanced when CeO2 is added to the noble metals supported Al2O3 catalysts. Reason for increase in catalytic activity is due to higher dispersion of noble metals in the form of ions in CeO2. This has led to the idea of substitution of noble metal ions in CeO2 lattice acting as adsorption sites instead of nanocrystalline noble metal particles on CeO2. In this article, a brief review of synthesis, structure and catalytic properties of noble metal ions dispersed on CeO2 resulting in noble metal ionic catalysts (NMIC) like Ce1-xMxO2-delta, Ce1-x-yTixMyO2-delta, Ce1-x-yZrxMyO2-delta, Ce1-x-ySnxMyO2-delta and Ce1-x-yFexMyO2-delta (M = Pt, Pd, Rh and Ru) are presented. Substitution of Ti, Zr, Sn and Fe in CeO2 increases oxygen storage capacities (OSC) due to structural distortion, whereas dispersion of noble metal ions in Ti, Zr, Sn and Fe substituted CeO2 supports increase both OSC and catalytic activities. Electronic interaction between noble metal ions and CeO2 in NMICs responsible for higher OSC and higher catalytic activities is discussed. (C) 2015 Published by Elsevier B.V.

Prospects of zero Schottky barrier height in a graphene-inserted MoS2-metal interface

A low Schottky barrier height (SBH) at source/drain contact is essential for achieving high drive current in atomic layer MoS(2-)channel-based field effect transistors. Approaches such as choosing metals with appropriate work functions and chemical doping are employed previously to improve the carrier injection from the contact electrodes to the channel and to mitigate the SBH between the MoS2 and metal. Recent experiments demonstrate significant SBH reduction when graphene layer is inserted between metal slab (Ti and Ni) and MoS2. However, the physical or chemical origin of this phenomenon is not yet clearly understood. In this work, density functional theory simulations are performed, employing pseudopotentials with very high basis sets to get insights of the charge transfer between metal and monolayer MoS2 through the inserted graphene layer. Our atomistic simulations on 16 different interfaces involving five different metals (Ti, Ag, Ru, Au, and Pt) reveal that (i) such a decrease in SBH is not consistent among various metals, rather an increase in SBH is observed in case of Au and Pt; (ii) unlike MoS2-metal interface, the projected dispersion of MoS2 remains preserved in any MoS2-graphene- metal system with shift in the bands on the energy axis. (iii) A proper choice of metal (e.g., Ru) may exhibit ohmic nature in a graphene-inserted MoS2-metal contact. These understandings would provide a direction in developing high-performance transistors involving heteroatomic layers as contact electrodes. (c) 2016 AIP Publishing LLC.

Bis(thiophenolate)pyridine pincer ligands and trivalent zirconocene complexes relevant to early transition metal polymerization catalysts

Two major topics are covered: the first chapter is focused on the development of post-metallocene complexes for propylene polymerization. The second and third chapters investigate the consequences of diisobutylaluminum hydride (HAlⁱBu₂) additives in zirconocene based polymerization systems.

The synthesis, structure, and solution behavior of early metal complexes with a new tridentate LX₂ type ligand, bis(thiophenolate)pyridine ((SNS) = (2-C₆H₄S)₂-2,6-C₅H₃N) are investigated. SNS complexes of Ti, Zr, and Ta having dialkylamido coligands were synthesized and structurally characterized. The zirconium complex, (SNS)Zr(NMe₂)₂, displays C₂ symmetry in the solid state. Solid-state structures of tantalum complexes (SNS)Ta(NMe₂)₃ and (SNS)TaCl(NEt₂)₂ also display pronounced C₂ twisting of the SNS ligand. 1D and 2D NMR experiments show that (SNS)Ta(NMe₂)₃ is fluxional with rotation about the Ta N(amide) bonds occurring on the NMR timescale. The fluxional behavior of (SNS)TaCl(NEt₂)₂ in solution was also studied by variable temperature ¹H NMR. Observation of separate signals for the diastereotopic protons of the methylene unit of the diethylamide indicates that the complex remains locked on the NMR timescale in one diastereomeric conformation at temperatures below -50 °C.

Reduction of Zr(IV) metallocenium cations with sodium amalgam (NaHg) produces EPR signals assignable to Zr(III) metallocene complexes. Thus, chloro-bridged heterobinuclear ansa-zirconocenium cation [((SBI))Zr(μ-Cl)₂AlMe₂]⁺B(C₆F₅)_4¯ (SBI = rac-dimethylsilylbis(1-indenyl)), gives rise to an EPR signal assignable to the complex (SBI)Zr^III(μ-Cl)₂AlMe₂, while (SBI)Zr^III-Me and (SBI)Zr^III(-H)2AlⁱBu₂ are formed by reduction of [(SBI)Zr(μ-Me)₂AlMe₂]⁺B(C₆F₅)_4¯ and [(SBI)Zr(μ-H)₃(AlⁱBu₂)₂]⁺B(C₆F₅)4¯, respectively. These products are also formed, along with (SBI)Zr^III-ⁱBu and [(SBI)Zr^III]⁺ AlR4¯ when (SBI)ZrMe₂ reacts with HAlⁱBu₂, eliminating isobutane en route to the Zr(III) complex. Studies concerning the interconversion reactions between these and other (SBI)Zr(III) complexes and reaction mechanisms involved in their formation are also reported.

The addition of HAlⁱBu₂ to precatalyst [(SBI)Zr(µ-H)₃(AlⁱBu₂)₂]⁺ significantly slows the polymerization of propylene and changes the kinetics of polymerization from 1st to 2nd order with respect to propylene. This is likely due to competitive inhibition by HAlⁱBu₂. When the same reaction is investigated using [(ⁿBuCp)₂Zr(μ-H)₃(AlⁱBu₂)₂]⁺, hydroalumination between propylene and HAlⁱBu₂ is observed instead of propylene polymerization.

Metasomatism and magmatic assimilation at a gabbro-limestone contact, Christmas Mountains, Big Bend region, Texas

A composite stock of alkaline gabbro and syenite is intrusive into limestone of the Del Carmen, Sue Peake and Santa Elena Formations at the northwest end of the Christmas Mountains. There is abundant evidence of solution of wallrock by magma but nowhere are gabbro and limestone in direct contact. The sequence of lithologies developed across the intrusive contact and across xenoliths is gabbro, pyroxenite, calc-silicate skarn, marble. Pyroxenite is made up of euhedral crystals of titanaugite and sphene in a leucocratic matrix of nepheline, Wollastonite and alkali feldspar. The uneven modal distribution of phases in pyroxenite and the occurrence' of nepheline syenite dikes, intrusive into pyroxenite and skarn, suggest that pyroxenite represents an accumulation of clinopyroxene "cemented" together by late-solidifying residual magma of nepheline syenite composition. Assimilation of limestone by gabbroic magma involves reactions between calcite and magma and/or crystals in equilibrium with magma and crystallization of phases in which the magma is saturated, to supply energy for the solution reaction. Gabbroic magma was saturated with plagioclase and clinopyroxene at the time of emplacement. The textural and mineralogic features of pyroxenite can be produced by the reaction 2( 1-X) CALCITE + AN_XAB_l-X = (1-X) NEPHELINE+ 2(1-X) WOLLASTONITE+ X ANORTHITE+ 2(1-X) CO₂. Plagioclase in pyroxenite has corroded margins and is rimmed by nepheline, suggestive of resorption by magma. Anorthite and wollastonite enter solid solution in titanaugite. For each mole of calcite dissolved, approximately one mole of clinopyroxene was crystallized. Thus the amount of limestone that may be assimilated is limited by the concentration of potential clinopyroxene in the magma. Wollastonite appears as a phase when magma has been depleted in iron and magnesium by crystallization of titanaugite. The predominance of mafic and ultramafic compositions among contaminated rocks and their restriction to a narrow zone along the intrusive contact provides little evidence for the generation of a significant volume of desilicated magma as a result of limestone assimilation.

Within 60 m of the intrusive contact with the gabbro, nodular chert in the Santa Elena Limestone reacted with the enveloping marble to form spherical nodules of high-temperature calc-silicate minerals. The phases wollastonite, rankinite, spurrite, tilleyite and calcite, form a series of sharply-bounded, concentric monomineralic and two-phase shells which record a step-wise decrease in silica content from the core of a nodule to its rim. Mineral zones in the nodules vary 'with distance from the gabbro as follows:

0-5 m CALCITE + SPURRITE + RANKINITE + WOLLASTONITE
5-16 m CALCITE + TILLEYITE ± SPURRITE + RANKINITE + WOLLASTONITE
16-31 m CALCITE + TILLEYITE + WOLLASTONITE
31-60 m CALCITE + WOLLASTONITE
60-plus CALCITE + QUARTZ

The mineral of a one-phase zone is compatible with the phases bounding it on either side but these phases are incompatible in the same volume of P-T-X_CO2.

Growth of a monomineralio zone is initiated by reaction between minerals of adjacent one-phase zones which become unstable with rising temperature to form a thin layer of a new single phase that separates the reactants and is compatible with both of them. Because the mineral of the new zone is in equilibrium with the phases at both of its contacts, gradients in the chemical potentials of the exchangeable components are established across it. Although zone boundaries mark discontinuities in the gradients of bulk composition, two-phase equilibria at the contacts demonstrate that the chemical potentials are continuous. Hence, Ca, Si and CO₂ were redistributed in the growing nodule by diffusion. A monomineralic zone grows at the expense of an adjacent zone by reaction between diffusing components and the mineral of the adjacent zone. Equilibria between two phases at zone boundaries buffers the chemical potentials of the diffusing species. Thus, within a monomineralic zone, the chemical potentials of the diffusing components are controlled external to the local assemblage by the two-phase equilibria at the zone boundaries.

Mineralogically zoned calc-silicate skarn occurs as a narrow band that separates pyroxenite and marble along the intrusive contact and forms a rim on marble xenoliths in gabbro. Skarn consists of melilite or idocrase pseudomorphs of melili te, one or two . stoichiometric calcsilicate phases and accessory Ti-Zr garnet, perovskite and magnetite. The sequence of mineral zones from pyroxenite to marble, defined by a characteristic calc-silicate, is wollastonite, rankinite, spurrite, calcite. Mineral assemblages of adjacent skarn zones are compatible and the set of zones in a skarn band defines a facies type, indicating that the different mineral assemblages represent different bulk compositions recrystallized under identical conditions. The number of phases in each zone is less than the number that might be expected to result from metamorphism of a general bulk composition under conditions of equilibrium, trivariant in P, T and u_CO2. The "special" bulk composition of each zone is controlled by reaction between phases of the zones bounding it on either side. The continuity of the gradients of composition of melilite and garnet solid solutions across the skarn is consistent with the local equilibrium hypothesis and verifies that diffusion was the mechanism of mass transport. The formula proportions of Ti and Zr in garnet from skarn vary antithetically with that of Si Which systematically decreases from pyroxenite to marble. The chemical potential of Si in each skarn zone was controlled by the coexisting stoichiometric calc-silicate phases in the assemblage. Thus the formula proportion of Si in garnet is a direct measure of the chemical potential of Si from point to point in skarn. Reaction between gabbroic magma saturated with plagioclase and clinopyroxene produced nepheline pyroxenite and melilite-wollastonite skarn. The calcsilicate zones result from reaction between calcite and wollastonite to form spurrite and rankinite.

A study of capacitance-voltage characteristics of lead zirconate titanate ferroelectric thin films and their usage to investigate polarization and coercive field.

Capacitance-voltage (C-V) characteristics of lead zirconate titanate (PZT) thin films with a thickness of 130 nm were measured between 300 and 533 K. The transition between ferroelectric and paraelectric phases was revealed to be of second order in our case, with a Curie temperature at around 450 K. A linear relationship was found between the measured capacitance and the inverse square root of the applied voltage. It was shown that such a relationship could be fitted well by a universal expression of C/A = k(V+V(0))(-1/2) and that this expression could be derived by expanding the Landau-Devonshire free energy at an effective equilibrium position of the Ti/Zr ion in a PZT unit cell. By using the derived equations in this work, the free energy parameters for an individual material can be obtained solely from the corresponding C-V data, and the temperature dependences of both remnant polarization and coercive voltage are shown to be in quantitative agreement with the experimental data.

Hydrogen sensors based on AlGaN/AIN/GaN HEMT

Pt/AlGaN/AIN/GaN high electron mobility transistors (HEMT) were fabricated and characterized for hydrogen sensing. Pt and Ti/Al/Ni/Au metals were evaporated to form the Schottky contact and the ohmic contact, respectively. The sensors can be operated in either the field effect transistor (FET) mode or the Schottky diode mode. Current changes and time dependence of the sensors under the FET and diode modes were compared. When the sensor was operated in the FET mode, the sensor can have larger current change of 8 mA, but its sensitivity is only about 0.2. In the diode mode, the current change was very small under the reverse bias but it increased greatly and gradually saturated at 0.8 mA under the forward bias. The sensor had much higher sensitivity when operated in the diode mode than in the FET mode. The oxygen in the air could accelerate the desorption of the hydrogen and the recovery of the sensor. (c) 2007 Elsevier Ltd. All rights reserved.

Hydrogen sensors based on AlGaN/AIN/GaN Schottky diodes

Pt/AlGaN/AIN/GaN Schottky diodes are fabricated and characterized for hydrogen sensing. The Pt Schottky contact and the Ti/Al/Ni/Au ohmic contact are formed by evaporation. Both the forward and reverse currents of the device increase greatly when exposed to hydrogen gas. A shift of 0.3 V at 300K is obtained at a fixed forward current after switching from N-2 to 10%H-2+N-2. The sensor responses under different concentrations from 50ppm H-2 to 10%H-2+N-2 at 373K are investigated. Time dependences of the device forward current at 0.5 V forward bias in N-2 and air atmosphere at 300 and 373K are compared. Oxygen in air accelerates the desorption of the hydrogen and the recovery of the sensor. Finally, the decrease of the Schottky barrier height and sensitivity of the sensor are calculated.