Normal Probability Plot Analysis Research Articles

PENGEMBANGAN BIOREAKTOR HIDROLISIS ENZIMATIS UNTUK PRODUKSI BIOETANOL DARI BIOMASSA JERAMI PADI

Human activity in modern life has disturbed air composition and causes many problems dealing with environmental issues such as acid rain and global warming. Carbon dioxide is a greenhouse gas, which the concentration in the air is increasing by 30% since the era of industrial revolution. Some activities, especially the usage of fossil fuel has cause the increasing of carbon dioxide concentration and other greenhouse gasses. When fossil fuels are consumed, carbon sequestered from the global carbon cycle for millions of years is released into the atmosphere, where it accumulates. One of effort need to be taken is to replace the usage of fossil fuel by bio-ethanol. Bio-ethanol consumption can release considerably less CO2 depending on how it is produced. Ethanol from cellulosic biomass could dramatically reduce emissions of the greenhouse gas, carbon dioxide (CO2). Although burning gasoline and other fossil fuels increases atmospheric CO2 concentrations, the photosynthetic production of new biomass takes up most of the carbon dioxide released when bio-ethanol is burned. Rice straw hydrolysis for the enzymatic production of ethanol has some benefits such as higher yield, minimum side reaction, lower energy consumption and lower operation condition. The research objective was to determine the optimum condition of rice straw hydrolysis process for bio-ethanol production by using Trichordema reseei. The research was divided into several research steps which were bioreactor fabrication, optimization of hydrolysis process parameters, mathematical modeling by regression analysis and glucose fermentation process. Optimization process was conducted by using 2n factorial design. Parameters studied in this research were substrate-enzyme ratio, water-rice straw ratio, pH and reaction time. From each variable we analyzed the glucose qualitatively and quantitatively. The determination of the most affecting variables was conducted by normal probability plot analysis. The calculation of main and interaction effect was conducted prior. The process variables that affect the rice straw hydrolysis process were pH and substrate-enzyme ratio. The optimum condition was achieved at enzyme-substrate ratio 1:1,4; where the glucose yield was 18,001% and the mathematical model was: . The optimum pH was hydrolysis process at pH 4,2 and the mathematical model was .

Piezoelectric Cs2S2O6: Room temperature crystal structure

Cesium dithionate, Cs2S2O6, is moderately strongly piezoelectric at room temperature and crystallizes in the hexagonal system with space group P63mc and two formula units in the unit cell. The lattice constants at 298 K are a=6.356 58±0.000 04 and c=11.539 07±0.000 04 Å (λCuKα1=1.5405 98 Å). The integrated intensities of most reflections with (sin ϑ)/λ?1.08 or 1.15 Å−1 were measured using two crystals and diffractometers. The first crystal gave a total of 1116 independent Fmeas, the second gave two separate sets of structure factors: 415 Fmeas with the crystal having received more radiation exposure than the first crystal and a further 431 Fmeas with still greater radiation exposure. The crystal structure was solved from the Patterson function and Fourier series and refined by the method of least squares. The final agreement factor R=0.033 for the first set, 0.049 and 0.060 for the second two sets of Fmeas. The crystal undergoes x-irradiation damage, with some reflections decreasing in integrated intensity by more than a factor of two. Normal probability plot analysis is used to compare the sets of Fmeas and resulting structural parameters. Redistribution of the Cs+ ions along the trigonal axes is likely, with compensating rearrangement of the S2O6−2 ions. The S2O6−2 ion has a staggered configuration close to 3̄m symmetry, with S–S=2.112±0.003, mean S–O=1.454±0.002 Å in length and S–S–O angle of 104.3±0.2 °, O–S–O=114.1±0.2 °. The two independent Cs+ ions are each nine-coordinated, with average Cs–O=3.231 Å. Layers with stoichiometric composition form normal to the polar axis.

Pyroelectric Ba(NO2)2⋅H2O: Room temperature crystal structure

Barium nitrite monohydrate, Ba(NO2)2⋅H2O, is strongly pyroelectric at room temperature and crystallizes in the hexagonal system with space group P65, or the enantiomorphous P61, and with six formulas in the unit cell. The lattice constants at 298 K are a=7.074 90±0.000 03 and c=17.890 87±0.000 12 Å (λCuKα1=1.540598 Å). The integrated intensities of most reflections within a quadrant of reciprocal space having radius (sinϑ)/λ?1.15 or 1.08 Å−1 were measured on two different crystals, each with different diffractometer, resulting in 3218 Fmeas for one set and 3671 Fmeas for the second set of independent structure factors. The crystal structure was solved from Patterson and Fourier series, and refined by the method of least squares. The final agreement factor R=0.026 for the first set, 0.018 for the second set of Fmeas. The two sets of Fmeas and the derived structural parameters are compared using normal probability plot analysis. The two NO−2 ions have a mean N–O distance of 1.246±0.002 Å and O–N–O angle of 114.2±0.2°. The Ba2+ ion is coordinated by nine oxygen and one nitrogen atoms at an average distance of 2.899 Å. The water molecule has a weighted mean O–H distance of 1.04±0.03 Å and H–O–H angle of 102.7°±4.3°: it is hydrogen bonded to two independent NO−2 ions by an O–H⋅⋅⋅O bond of 2.878 Å and an O–H⋅⋅⋅N bond of 2.951 Å.

Exchange interactions in di-µ-hydroxo-bis[bis(1,2-diaminoethane)-chromium(III)] salts. Structural, magnetochemical, and optical spectroscopic investigations

Chloride, bromide, iodide, and dichloride diperchlorate salts of the title complex have been prepared. The crystal structures of [Cr2(OH)2(en)4]Cl4·2H2O and [Cr2(OH)2(en)4]Br4·2H2O have been determined by single-crystal X-ray measurements on an automatic diffractometer, and refined to R 0.023 for the chloride and 0.031 for the bromide. Lattice constants are a= 8.165 0(8), b= 8.740 0(9), c= 9.790 2(7)A, α= 67.196(7), β= 87.937(7), and γ= 64.587(7)° for the chloride, and a= 8.211(2), b= 8.980(1), c= 10.024(1)A, α= 67.57(1), β= 88.90(1), and γ= 65.07(2)° for the bromide. Both structures belong to space group P and are strictly isomorphous. The symmetry of the dichromium complex is 2/m in both salts. Moreover, a normal probability plot analysis shows the cations to be identical in the two compounds. Powder magnetic-susceptibility data have been collected for all the four complexes between 1.5 K and room temperature. Single-crystal and Nujol-mull absorption spectra have been recorded between 7 and 40 K in the region of transitions from the electronic ground state 4A24A2 to the lowest levels of the first singly excited state 4A22E, and powder luminescence spectra obtained at <10 K. From the absorption and luminescence spectra the exchange splitting of the electronic ground state can be accurately determined. The exchange parameters J thus derived deviate by up to 10% from those obtained by fitting the magnetic-susceptibility data. These discrepancies indicate a slight temperature dependence of J. The values obtained for the biquadratic exchange parameter j from the magnetochemical fit have little if any physical significance. The exchange parameters (cm–1) for the four salts, determined spectroscopically at <40 K, are: J= 31.4 ± 0.4 and j= 0.08 ± 0.02 (chloride), 30.0 ± 0.3 and j= 0.11 ± 0.08 (bromide), 24.3 ± 0.9 and j= 0.08 ± 0.2 (iodide), and 22.2 ± 0.2 and j= 1.12 ± 0.6 (dichloride diperchlorate dihydrate).

Pyroelectric 3La(IO3)3⋅HIO3⋅7H2O. Crystal structure of the transition metal iodates. V.

3La(IO3)3⋅HIO3⋅7H2O is pyroelectric and piezoelectric at room temperature and crystallizes in the orthorhombic space group Aba2 with four formulas in the unit cell. The lattice constants at 298 °K are a=13.18008(10), b=21.72076(10), c=12.15514(18) Å (for λ CuKα1=1.540562 Å). The integrated intensities of most reflections within a hemisphere of reciprocal space with radius (sinϑ)/λ=1.02 Å−1 were measured on two different crystals, each with a different diffractometer, resulting in 2742 symmetry-independent Fmeas for one set and 4038 Fmeas for the second set of structure factors. The crystal structure was solved by use of Patterson and Fourier methods, and refined by the method of least squares. The final agreement factor R=0.063 for the first set and 0.040 for the second, for models in which all atoms but hydrogen undergo anisotropic thermal vibrations. Normal probability plot analysis is used to compare the two sets of data and parameters. The absolute configuration of the crystal has been determined. Evidence for lattice damage caused by x irradiation is presented. The iodate ions form an oxygen-sharing network, with one independent La3+ occupying distorted bicapped, the other distorted equatorially-girdled, trigonal prismatic interstices. Each of the five independent IO−3 ions form triangular pyramids with three short I–O bonds of average length 1.803 Å: Three iodine atoms are associated with two next-nearest oxygen neighbors at 2.80 Å, one has three next-nearest neighbors also at 2.80 Å, and the fifth has four next-nearest neighbors at 2.91 Å, on average. An extensive O⋅⋅⋅O hydrogen bond network, with shortest distance of 2.619 Å, connects water molecules and iodate ions. Evidence for H3O+ formation by the iodic acid proton, and for the positions of the hydrogen atoms associated with the four independent water–oxygen atoms, is discussed.

Piezoelectric langbeinite-type K2Cd2(SO4)3 structure at four temperatures below and one above the 432°K ferroelastic–paraelastic transition

K2Cd2(SO4)3 is orthorhombic below 432°K, with space group P212121, and cubic above with space group P213. A structural study has been completed at 298, 351, 390.5, 417.5, and 443.5°K based, respectively, on 3383, 1377, 1803, 1724, and 1022 symmetry-independent structure factors. Measurement of integrated intensities was made using a CAD-4 diffractometer with Nb-filtered MoKα radiation. An air-flow microfurnace with temperature controller provided a thermal stability better than ±1°. The a, b, c lattice constants in the orthorhombic phase are 10.2084(8), 10.2813(8), 10.1684(8) Å at 298°K; 10.2239(8), 10.2897(8), 10.1821(8) Å at 351°K; 10.2386(8), 10.2951(8), 10.1981(8) Å at 390.5°K; and 10.2501(10), 10.2972(8),10.2132(9) Å at 417.5°K. In the cubic phase, a=10.2704(10) Å at 443.5°K. The model previously obtained at room temperature [J. Chem. Phys. 67, 2146(1977)] was refined by the method of least squares using the new sets of measurements. The final agreement factors are R=0.028 (298°K), 0.032(351°K), 0.026(390.5°K), 0.037(417.5°K), and 0.026(443.5°K). Normal probability plot analysis shows the furnace does not introduce new systematic error in the Fmeas. The amplitudes of thermal vibration for the oxygen atoms increase gradually between 298 and 417.5°K and sharply between 417.5 and 443.5°K. The metal atom vibrations have smaller increases. The metal ions undergo displacements averaging 0.16 Å at the transition, with displacements in the orthorhombic phase averaging 0.05 Å over a 120°K interval. The sulfur atom displacements are comparable, with simultaneous rotations of the SO2−4 tetrahedra. Two K–O contacts are broken and one is made in the K1+ coordination polyhedra at the phase transition. The Cd–O coordination polyhedra remain unchanged.

Pyroelectric α-Cu(IO3)2. Crystal structure of the transition metal iodates. III

Alpha-cupric iodate, α-Cu(IO3)2, is pyroelectric and piezoelectric at room temperature and crystallizes in the monoclinic space group P21 with two formulas in the unit cell. The lattice constants at 298 °K are a =5.56902 ± 0.00010, b=5.11098 ± 0.00009, c=9.26976 ± 0.00036 Å and β=95.82 ± 0.02 ° (λCuKα1 − 1.540562 Å). The integrated intensities of most reflections within a hemisphere of reciprocal space with radius (sinϑ)/λ?1.02 Å−1 were measured on two different crystals using two different diffractometers, resulting in 1814 Fmeas for one set and 4272 Fmeas for the second set of independent structure factors. The crystal structure was solved using Patterson and Fourier series and refined by the method of least squares, the final agreement factor R becoming 0.063 for the first set, and 0.035 for the second set of Fmeas. The iodate ions form a nearly-regular hexagonal closest-packed array, with Cu2+ in the resulting octahedral interstices. The two independent iodate groups, each with three short I–O distances averaging 1.82 Å, share oxygen atoms to form a three-dimensional framework of corner-sharing polyhedra. One iodate ion forms three additional I–O distances averaging 2.66 Å, the other has four that average 2.95 Å. The CuO6 octahedron is tetragonally distorted, with four bonds averaging 1.97 Å and two apical Cu–O bonds averaging 2.39 Å. The two sets of Fmeas, and the resulting derived structural parameters, are compared using normal probability plot analysis.

Paramagnetic Ni(IO3)2 · 2H2O. Crystal structure of the transition-metal iodates. I

Nickel iodate dihydrate, paramagnetic at room temperature and weakly ferromagnetic below 3 °K, crystallizes in the orthorhombic system with space group Pbca and four formulas in the unit cell. The lattice constants at 298 °K are a = 9.14986 ± 0.00008, b = 12.20896 ± 0.00022, and c = 6.58353 ± 0.00013 Å. The crystal structure has been investigated independently in two laboratories. In one, the integrated intensities of 8883 reflections were measured with PEXRAD, within a hemisphere of reciprocal space of radius (sinθ)/λ = 1.02 Å−1. In the other, all independent reflections with (sinθ)/λ ≤ 0.70 Å−1 were measured on a Nonius automatic three-circle diffractometer. The crystal structure was solved by interpretation of Patterson and Fourier series, and refined by the method of least squares, using respectively 824 or 864 symmetry-independent structure factors. The final agreement factor is 0.047 for one set and 0.048 for the other, based on anisotropic temperature coefficients for all atoms except hydrogen, for which isotropic values were used. The structure consists of a network of corner-sharing IO6 octahedra with the Ni ions occupying octahedral interstices at the inversion centers. The water oxygen forms part of the octahedra around Ni, and is not directly bonded to I. The IO6 octahedra are highly distorted, with three I–O distances in the range 1.801–1.820 Å and three more in the range 2.804–2.935 Å. The NiO6 octahedra are almost regular, with Ni–O distances in the range 2.042–2.062 Å and O–Ni–O angles in the range 88.3–89.9°. The hydrogen atoms of the water molecule were detectable, and refinement gave acceptable molecular dimensions. Normal probability plot analysis was used to compare the results of the two independent structural investigations.

Normal probability plot analysis of small samples

In using normal probability plots for comparing two sets of crystallographic data [Abrahams, S. C. & Keve, E. T. (1971), Acta Cryst. A27, 157] note should be taken of the fact that the expected values of normal order statistics are not given exactly by the percentage points of the normal distribution. This becomes an important consideration only for small samples. Tables of expected ranked exact moduli of normal observations, for sample sizes to 41, are presented: these are useful for half-normal probability plots.

Rutile: Normal Probability Plot Analysis and Accurate Measurement of Crystal Structure

The x-ray scattering by two different rutile crystals, within a hemisphere of reciprocal space having radius (sin θ) /λ=1.02 Å−1, was measured at 298°K with PEXRAD. The integrated intensities of 780 reflections from each crystal were determined, resulting in 136 symmetry independent Fmeas from Crystal 1 and 122 Fmeas from Crystal 2. The crystal structure was refined by the method of least squares: The agreement factor R for all Fmeas is 0.0286, and the single position parameter x(0)=0.30479±0.00010. Normal probability plot analysis shows the least squares derived standard deviations are underestimated by 33%, and the two sets of Fmeas contain an appreciable parallel bias. The lattice constants, measured at or corrected to 298°K on two different crystals, are a=4.593659±0.000019 and c=2.958682±0.000008 Å. The Ti–O distances are 1.9800±0.0009 and 1.9485±0.0005 Å. Pairs of shorter bonds define O–Ti–O angles of 81.21° and 98.79°, forming a plane normal to the two longer bonds. The resulting octahedral Ti–O bond arrangement is apically extended, as is found in all AIVB2 compounds with rutile structure: The remaining nine well-determined non-Group IV AB2 family members contain, without exception, apically compressed AB6 octahedra. Bauer and Khan's, and also Niizeki's, x-ray results on rutile are compared with the present measurements.

Application of normal probability plot analysis to lutetium orthoborate factors and parameters

The methods of normal probability plot analysis have been applied to two nearly complete sets of structure factors (F meas) and the corresponding objectively assigned standard deviations (σF meas) obtained by diffractometer measurement with two different crystals of lutetium orthoborate. The least-squares derived positional and thermal vibration parameters are shown to be too small by a factor of 1.8, and the σF meas to be overestimated by a factor of 1.55. The two sets of F meas are found to contain a small but parallel bias. The lattice constants of rhombohedral calcite-type LuBO3 are measured as a H = 4.91538±0.00002 Å and cH = 16.21200±0.00003 Å at 298°K, with six formulas in the unit cell, space group R\overline 3c. The Lu–O distance in this six-coordinated Lu compound is 2.240±0.002 Å (corrected standard deviation). The B–O distance in the BO3 triangular groups is 1.370±0.005 Å. The characteristic Θ temperature is estimated as 446±19°K.

Luminescent Piezoelectric CdSiP2: Normal Probability Plot Analysis, Crystal Structure, and Generalized Structure of the AIIBIVC2V Family

CdSiP2 is a typical member of the AIIBIVC2V family with chalcopyrite structure. The x-ray scattering for luminescent and nonluminescent material is essentially identical: The atomic order at the Cd and Si sites is at least 99.8% complete. The lattice constants of this tetragonal crystal are a = 5.680 ± 0.001 and c = 10.431 ± 0.003 Å at 298°K. The space group is I4̄2d, and there are four formulas per unit cell. A total of 2370 reflections from a nonluminescent crystal, and 2156 from a luminescent CdSiP2 crystal, were measured with PEXRAD. Least squares refinement, based on 320 symmetry-independent reflections from both crystals, led to a final agreement factor of 0.047. Normal probability plot analysis shows the least squares derived standard deviations to be underestimated by a factor of 3.0, and the two sets of measured structure factors to possess a small parallel bias. The bond angles about the Si atom do not differ significantly from the regular tetrahedral angle of 109.47°. Regular tetrahedral bond angles about Si were previously observed in ZnSiP2. The assumption that the BIV atom in all members of the AIIBIVC2V family maintains a regular tetrahedral valence angles leads to the relation: x = 0.5 − (c2 / 32a2 − 11 6)1/2, where x is the atomic coordinate of the CV atom at position x1418. The predicted interatomic distances for a wide group of family members are both internally consistent and in excellent agreement with measurement on ZnSiP2 and CdSiP2. The experimental Cd–P distance is 2.561 ± 0.002 Å, and Si–P is 2.247 ± 0.002 Å. The CdSiP2 characteristic temperature θ is 282°K, and representation is ΠPP(4̄2m).

Normal probability plot analysis of error in measured and derived quantities and standard deviations

Normal probability plot analysis is applied to independent sets of crystallographic structure factor measurements (F) and the derived coordinates (p). Differences between corresponding pairs of structure factors (ΔF) in the two sets are examined in terms of their pooled standard deviations (σF) by plotting the ordered statistic δm = ΔF/σF against the expected normal distribution. Differences between pairs of coordinates (Δp) are similarly examined in a δp = Δp/σp half-normal probability plot. Both plots result in linear arrays of unit slope and zero intercept, for normal error distribution in the experiment and the model and correctly assigned standard deviations. Analysis of departures from this ideal, especially when both plots are considered together, provides detailed information of the kinds of error in δm and in δp. By inference, the kinds of error in F and σF as well as in p and σp can be deduced. The normal probability plot δR = |Fmeas| − |Fcalc|/σFmeas should ideally also be linear, with unit slope and zero intercept. Deviations from ideal provide considerably more information than the conventional R values. Analysis of δR in combination with δm plots allows further specification of the error distribution. Examples using these plots are given and discussed, based both on real and on simulated data.