Lang Method Research Articles

Intercomparison of leaf area index observed by destructive sampling, plant canopy analyzer and tracing radiation and architecture of canopies in paddy fields

ABSTRACT Leaf area index (LAI) is a canopy structure parameter used to characterize vegetation growth. It is increasingly important to obtain continuous and accurate ground LAI measurement data for the validation of remote-sensing products. In this study, direct destructive sampling method and indirect optical measurement including LAI-2200 plant canopy analyser (PCA) and Tracing Radiation and Architecture of Canopies (TRAC) were used for long-term continuous observation of paddy fields in southern China, to explore the variation of LAI during the growth period of paddy, and to quantitatively analyse the errors of indirect optical measurement. The results show that (1) LAI and Plant area index (PAI) increased first and then decreased in the growing period. The proportion of green leaf area gradually decreased at reproductive growth stage (less than 50%). There was a linear relationship between the proportion of green leaf area and PAI at this stage, with a good correlation (R2 = 0.73). This linear relationship can be used to convert PAI into LAI more conveniently. (2) Effective PAI (PAIe) calculated by the two methods (2000 method and Lang method) from PCA showed good consistency between each other in the growing season (the maximum value of R2 is 0.99). With the increase of zenith angle, the consistency between 2000 method and Lang method decreases (R2 = 0.83). Multiple scattering has an effect on PCA measurement, and this effect is more obvious at high zenith angle. Lang method is more sensitive to the change of zenith angle. (3) Compared to the destructive values, both 2000 method and Lang method are able to compute accurate LAI using four ring sensors (4 R), while TRAC underestimates the LAI and PAI from destructive sampling method. This study provided a new idea for reducing the impact of ground reference data errors on LAI product validation.

Effectiveness of the habit of using mask and not using mask on the carboxyhemoglobin (COHb) levels in public transportation workers in Bangkalan district

Introduction: Air pollution is increasing due to industrial and transportation activities in the community. This has an impact on health problems, one of which is respiratory problems. Carbon monoxide (CO) is one of the air pollutants resulting from incomplete combustion of transportation and can be harmful to the human body. The purpose of this study was to analyze the levels of carboxyhemoglobin (CoHb) and the effect of the habit of wearing a mask and not using a mask on COHb levels in public transportation workers in the Bangkalan district. Method: We used analytic observational with cross-sectional design. Respondents used in this study were public transportation workers who had the habit of wearing masks and not wearing masks in the Bangkalan district. COHb levels were checked using the Hinsberg Lang method by reading a UV-Vis spectrophotometer at a wavelength of 414.2 nm with normal values for COHb levels < 3.5%. Results: There were 13% respondents who had the habit of using masks and smoking, 37% respondents were non-smokers and use masks. While respondents who did not have the habit of using masks and smoking were 27% and non-smokers were 23%. Respondents who smoked and used masks had an average COHb level of 8.56%, whereas those who did not smoke and used masks had an average COHb level of 6.50%. Respondents who smoked and did not use masks had an average COHb level of 9.36%, while those who did not smoke and did not use masks had average COHb levels of 8.08%. Bivariate analysis showed that COHb levels were higher in public transportation workers who did not use masks than those who used masks while working (p < 0.05). Conclusion: We discovered a correlation between the habit of wearing a mask and the levels of COHb in those who work in public transport in the Bangkalan District. The analysis of respondents' COHb levels based on the type of mask used and consideration of underlying disease should be done in future studies.

Study of the Technical-Economic Feasibility of a Pyrolysis/Gasification Plant for the Generation of Liquid Gas Fuels from Plastic Waste

Pyrolysis can offer a practical environmental solution for recycling plastic waste, converting it into liquid and gaseous fuels of high commercial value. This article proposed the simulation in Aspen Plus® of a pyrolysis/gasification plant, having plastic residues and residual soybean oils as raw material. The products generated in the gasifier are bio-oil and synthesis gas, which can be converted into ethylene and gasoline in reactors. To calculate the plant’s cost of capital, the Lang Method was used. The economic indicators NPV, IRR, PI, and Payback determined the project’s viability. The works show that the current scenario studied has economic viability, but better results can be achieved with increasing project maturity.

Association of Major Chronic Noncommunicable Diseases and Life Expectancy in China, 2019.

This study aimed to illustrate the association of four major chronic noncommunicable diseases (cardiovascular diseases, cancer, respiratory diseases, and diabetes) with life expectancy (LE) of Chinese residents in 2019 and to provide an evidence base for the scientific prevention and treatment of chronic diseases in China. The abbreviated life and cause-eliminated life tables were compiled according to the Jiang Qing Lang method recommended by WHO (World Health Organization) to calculate LE and cause-eliminated life expectancy (CELE) in 2019. The disease that had the greatest association with the LE of Chinese residents was cardiovascular disease (CVD), with the LE increasing by 8.13 years after removing CVD deaths. This was followed by cancer (2.68 years), respiratory diseases (0.88 years), and diabetes (0.24 years). The four major chronic noncommunicable diseases (NCDs) were the main diseases affecting the health of Chinese residents. CVD should be prevented and treated as the key disease among the chronic diseases, while women and rural people should be the major focus of health knowledge promotion. All residents should be encouraged to develop a good understanding of self-protection and of how to achieve a healthy lifestyle in order to reduce the occurrence of death and to improve their quality of life and health in general.

Test scores’ robustness to scaling: The scale_transformation command

Social scientists frequently rely on the cardinal comparability of test scores to assess achievement gaps between population subgroups and their evolution over time. This approach has been criticized because of the ordinal nature of test scores and the sensitivity of results to order-preserving transformations that are theoretically plausible. Bond and Lang (2013, Review of Economics and Statistics 95: 1468–1479) document the sensitivity of measured ability to scaling choices and develop a method to assess the robustness of changes in ability over time to scaling choices. In this article, I present the scale_transformation command, which expands the Bond and Lang (2013) method to more general cases and optimizes their algorithm to work with large datasets. The command assesses the robustness of an achievement gap between two subgroups to any arbitrary choice of scale by finding bounds for the original gap estimation. Additionally, it finds scale transformations that are very likely and unlikely to benchmark against the results obtained. Finally, it also allows the user to measure how much gap growth coefficients change when including controls in their specifications.

Antidepressant and antinociceptive activities in animal models and in vitro assessment of the anti-thyroid activity of bis(DL-pyroglutamate)magnesium complex.

Magnesium is an essential element related with biochemistry of the brain and different types of depression have been associated with its deficiency. The structure of a novel magnesium bis(DL-pyroglutamate) (Mg(DL-pGlu)2) was elucidated by X-ray crystallography. Wistar rats were used in the in vivo experiments. The antidepressant-like effect was assessed by the forced swim test (FST) and the antinociceptive activity was evaluated using hot plate test. In both, non-specific effects were evaluated by the open field test. Anti-thyroid activity was examined using Lang's method. Albumin binding behavior was evaluated by 3D fluorescence spectroscopy. For the Mg(DL-pGlu)2 complex (30 mg/kg), the FST test on Wistar rats revealed a decrease of 22% in the immobility time and an increment of 106% in the swimming time. The compound alters neither the locomotor activity nor the body weight after chronic administration. At the same dose, it showed antinociceptive activity, increasing the response latency. It blocks iodination reactions generating a charge transfer complex with iodine hence indicating anti-thyroid activity (Kc = 45366.5 ± 29 M-1). Albumin 3D fluorescence spectroscopy experiments showed intensity increase of peak A and decrease of peak B. The results showed that the new compound produced a lowering of the immobility time and an increment of the swimming ability of the rats. The compound is able to increase the response latency in 70.0%, to capture iodine (anti-thyroid activity) and to interact with albumin through covalent type of interaction of the free NH groups.

The growth and perfection of β-cyclotetramethylene-tetranitramine (HMX) studied by laboratory and synchrotron X-ray topography

An examination has been made of the defect structure of crystals of the energetic material β-cyclotetramethylene-tetranitramine (HMX) using both Laboratory (Lang method) and Synchrotron (Bragg Reflection and Laue method) techniques. The results of the three methods are compared with particular attention to the influence of potential radiation damage caused to the samples by the latter, more energetic, technique. The comparison shows that both techniques can be confidently used to evaluate the defect structures yielding closely similar results. The results show that, even under the relatively casual preparative methods used (slow evaporation of unstirred solutions at constant temperature), HMX crystals of high perfection can be produced. The crystals show well defined bulk defect structures characteristic of organic materials in general: growth dislocations, twins, growth sector boundaries, growth banding and solvent inclusions. The distribution of the defects in specific samples is correlated with the morphological variation of the grown crystals. The results show promise for the further evaluation and characterisation of the structure and properties of dislocations and other defects and their involvement in mechanical and energetic processes in this material.

Estimation of permeability of 3-D discrete fracture networks: An alternative possibility based on trace map analysis

The permeability of 3-D discrete fracture networks (DFNs) is estimated based on the geometrical parameters of 3-D model and permeability of its 2-D trace maps. This is achieved by the analysis of 84 3-D DFN models and 672 2-D DFN models that are cut from 3-D ones. The relationships between permeability of 3-D model and parameters such as fracture density, fracture length exponent of 3-D models and permeability of 2-D cut planes were analyzed. A multi-variable regression function was proposed for predicting 3-D fracture network permeability. The results show that the dimensionless equivalent permeability of 3-D fracture networks increases with the increasing fracture density following linear relationship. For the fracture networks with the fracture length exponent a=2.0, the fracture network that carries flow is mainly consisted of several long fractures; whereas the fracture network connectivity is dominated by a large amount of relatively small fractures when a=4.5. The permeability of 2-D DFN models that are cut from an original 3-D one underestimates the permeability of 3-D DFNs by approximately 10.45–80.92%. The regression function estimates the evolution of permeability of 3-D DFNs with a wide range of fracture density from 0.025 to 0.125m−3, and the predicted results agree with that calculated using Lang's method. The proposed model provides a simple method to approximate permeability of 3-D fracture networks using parameters that can be easily obtained from analysis on outcrop trace maps of fractured rock masses.

X-ray topographic study of growth defects of trans-stilbene crystals grown from solutions

Single crystals of trans-stilbene, C14H12, with properties suitable for high-energy neutron detection were grown from solution in anisole and toluene by the temperature reduction method with growth rates up to 6 mm/day. From these crystals, slices of appropriate orientation and thickness of 2–4mm were cut and studied by X-ray diffraction topography applying the Lang method using CuKα radiation. The topographs exhibit growth defects such as liquid inclusions, dislocations, striations, and faulty growth-sector boundaries. These defects occur in the same typical arrangements and geometries as is observed in all kinds of crystals grown on habit faces from solution. Besides growth dislocations originating from inclusions and propagating with the growth front, many plastic glide dislocations in the shape of loops or half-loops emitted from inclusions by stress relaxation are observed. The glide system underlying this plasticity is discussed.

Study of the internal structure of lithium fluoride single crystal by laboratory X-ray topo-tomography

Defects in a synthetic LiF crystal have been studied by X-ray topo-tomography on laboratory X-ray sources with a spatial resolution of ∼10 μm. An algebraic reconstruction method was applied to reconstruct the defect 3D structure of the crystal based on the diffraction data. The results presented in this study are in good agreement with the topographic data obtained by the Lang method.

X-ray diffraction study of silicon single crystals highly doped with boron

The section Lang method of X-ray diffraction topography in combination with X-ray diffractometry based on the Borrmann effect was previously shown to be effective for detection of cluster formation during the growth process of highly doped Si-Cz single crystals. In the present work, the same techniques have been used to choose the best condition of technological heat treatment of boron-doped silicon from the view-point of formation of microdefects. The concentration and average size of dislocation loops have been calculated for two conditions of standard heat treatment from the analysis of diffusion scattering. The distribution of dislocation loops along the growth axis and crystal diameter has been determined as well.

Andrew Richard Lang, Hon. FRSSAf 1924–2008

"Andrew Richard Lang, Hon. FRSSAf 1924–2008." Transactions of the Royal Society of South Africa, 63(2), p. 194

Chronostratigraphy of a sediment record from the Hajar mountain range in north Oman: Implications for optical dating of insufficiently bleached sediments

In this study we report on optical stimulated luminescence (OSL) ages of quartz extracted from a sedimentary record in the N-Oman mountain range. Equivalent dose ( D E ) distributions derived from single aliquot measurements (SAR) of small aliquots (ca. 200 grains) were investigated to test whether the skewness and broadness of the dose distribution can be used as criteria for the identification of insufficient bleaching. Furthermore, the methods proposed by Lepper and McKeever [2002 An objective methodology for dose distribution analysis. Radiation Protection Dosimetry 101 (1–4), 349-352]. Singhvi [Juyal, N., Chamyal, L.S., Bhandari, S., Bushan, R., Singhvi, A.K., in press. Continental record of the southwest monsoon during the last 130 ka: evidence from the southern margin of the Thar Desert, India. Quaternary Science Review] and Fuchs and Lang [2001 Fuchs, M., Lang, A., 2001. OSL dating of coarse-grain fluvial quartz using single-aliquot protocols on sediments from NE Peloponnese, Greece. Quaternary Science Review 20, 783–787.] to derive D E 's from insufficiently bleached sediments were compared. At first, the investigations were carried out on artificially bleached, irradiated and mixed quartz material from the Oman study area to simulate insufficiently bleached sediments. Then, the various statistical methods for identifying insufficient bleaching and D E derivation were applied to the natural samples from the study area, where 18 samples were measured. For the identification of insufficient bleaching the preferential parameter is the broadness of a distribution. For D E calculation, both the Singhvi method and the Fuchs and Lang method produce similar results, which are consistent with the stratigraphic order. A drawback of both methods is their sensitivity to low outliers. The Lepper and McKeever method was not applied to the natural samples, due to limitations in its application to a small number of aliquots and due to the ambiguous identification of the rising limb of the dose distributions.

XRDT Study of Structural Defects of 6H-SiC Crystals

X-Ray Diffraction Topography (XRDT) and Optical Microscopy (OM) are adopted to study extended structural defects in 6H-SiC bulky crystals. Topographs are taken by means of White Beam Synchrotron Radiation Source (WB-SRS-XRDT) and by means of monochromatic radiation (MoKα1) with conventional source (Lang method). All studied samples are characterised by the presence of linear defects, dislocations and microchannels, uniformly distributed in the crystal. Such defects draw a net of independent systems of parallel lines, with different orientation and different contrast widths. Micro-channels are parallel to the c axis, whereas dislocations are perpendicular or nearly parallel to the c axis. The last are unit screw dislocations. It has been concluded that the growth mechanism is driven by screw dislocations and that channels results from the coalescence of parallel dislocations.

The multiphase Eulerian-Lagrangian transport (MELT-3D) approach for modeling of multiphase mixing in fragmentation processes : Nourgaliev, R. R. et al. Progress in Nuclear Energy, 2003, 42, (2), 123–157

In this study we report on optical stimulated luminescence (OSL) ages of quartz extracted from a sedimentary record in the N-Oman mountain range. Equivalent dose (DE) distributions derived from single aliquot measurements (SAR) of small aliquots (ca. 200 grains) were investigated to test whether the skewness and broadness of the dose distribution can be used as criteria for the identification of insufficient bleaching. Furthermore, the methods proposed by Lepper and McKeever [2002 An objective methodology for dose distribution analysis. Radiation Protection Dosimetry 101 (1–4), 349-352]. Singhvi [Juyal, N., Chamyal, L.S., Bhandari, S., Bushan, R., Singhvi, A.K., in press. Continental record of the southwest monsoon during the last 130 ka: evidence from the southern margin of the Thar Desert, India. Quaternary Science Review] and Fuchs and Lang [2001 Fuchs, M., Lang, A., 2001. OSL dating of coarse-grain fluvial quartz using single-aliquot protocols on sediments from NE Peloponnese, Greece. Quaternary Science Review 20, 783–787.] to derive DE's from insufficiently bleached sediments were compared. At first, the investigations were carried out on artificially bleached, irradiated and mixed quartz material from the Oman study area to simulate insufficiently bleached sediments. Then, the various statistical methods for identifying insufficient bleaching and DE derivation were applied to the natural samples from the study area, where 18 samples were measured. For the identification of insufficient bleaching the preferential parameter is the broadness of a distribution. For DE calculation, both the Singhvi method and the Fuchs and Lang method produce similar results, which are consistent with the stratigraphic order. A drawback of both methods is their sensitivity to low outliers. The Lepper and McKeever method was not applied to the natural samples, due to limitations in its application to a small number of aliquots and due to the ambiguous identification of the rising limb of the dose distributions.

Phenomena and mechanisms of mixed crystal formation in solutions I. General concept on the example of the system KHC 8H 4O 4–RbHC 8H 4O 4–H 2O

A comprehensive study of crystal morphology and imperfections in the isomorphic series potassium acid phthalate–rubidium acid phthalate (KAP–RbAP) in aqueous solutions was conducted using a general model of the processes of mixed crystal formation in solutions discussed earlier by the authors on experimental and theoretical basis. The system was chosen as a model to interpret basic processes. The utilization of both substances as well as their solid solutions was taken into account. Interaction between RbAP or KAP crystals and aqueous solutions saturated with either KAP or RbAP or both, in ratios varying from 10 to 90 wt% (the step was about 10 wt%), has been studied. All the processes were observed in situ and ex situ by optical microscopy and X-ray topography (Lang method). Solubilities of KAP and RbAP mixtures in water were determined and compositions of corresponding solid solutions were estimated for the isotherms 29°C and 39°C. These indicated a considerable convex curvature in concentration Schreinemakers diagrams. The main peculiarity of crystals is their having heteroepitaxial porous or uniform textures, which occur due to the secondary volume deficit or excess at the exchange reaction between a crystal and solution. In turn, the primary/secondary volume ratio depends on the solubilities of the components in the system (unconnected with the molar volumes of the substances) determined directly from Schreinemakers diagrams. The convexity of the KAP–RbAP solubility isotherms displays specific crystal formation in this system compared with features of Co–Ni Tutton salts whose isotherms have small curvatures. Firstly, this appeared as a shift from volume-deficit replacement toward volume-excess replacement. This resulted in non-uniform heteroepitaxial textures and sharp slowing down of the process at an intermediate stage. Phenomena occurring in such peculiar systems and interactions between the crystals and solutions of intermediate compositions have not been investigated before. The results obtained became a basis for developing a theory of mixed crystal formation in solutions. Optically transparent mixed monocrystals containing about 3 and 5–10 wt% RbAP were isolated from solutions having the KAP/RbAP ratios of components 90/10 and 80/20 wt%.

Plastic deformation of copper single crystals by simulation using X-ray Lang method and molecular dynamics

Copper rectangular parallelepiped single crystals with a notch have been extended or compressed. In a crystal with a notch, partial dislocations were created near the tip of the notch in elongation as we expected. It is hard to see where the dislocations were created just looking the displaced positions of atoms, but by a simulation of X-ray Lang topography, the creation of dislocations was easily observed. Before creation of dislocations, some indication was quite clearly shown. For compression dislocations did not start near the tip of the notch but started uniformly on the surface, the effect of notch was minor.

TENSILE DEFORMATION OF COPPER SINGLE CRYSTALS BY SIMULATION USING X-RAY LANG METHOD AND MOLECULAR DYNAMICS

Simulations were performed to model the response of a copper rectangular parallelepiped single crystal with a notch to tensile deformation. Partial dislocations were created near the tip of the notch as we expected. It is hard to see where the dislocations were created by just looking at the displaced positions of atoms, but the creation of dislocations was easily observed by a simulation of X-ray Lang method. Before creation of dislocations, some indication was quite clearly shown. Laue patterns during tensile deformation were also simulated.

Preliminary Characterization of Loop-Shaped Defect in the AlPdMn IcosahedralQuasicrystal by Conventional X-Ray Topography

Loop-shaped contrasts were observed in theas-grown Al70.3Pd20.6Mn9.1 icosahedral quasicrystal (IQC)by means of x-ray diffraction topography (Lang's method). One possibledirection of the apparent Burger vectors of loop-shaped defects (LSDs)was determined to be B = [11̅01̅01] by the invisibilitycriterion, whose physical component is parallel to the two-fold axis 1/τ[1̅/0,1/1,0/1̅] of the IQC. Apart from the relaxation ofstrain fields around the faceted dodecahedral holes and lamellarprecipitates, LSDs may well originate from the growth of the quasicrystal,which shows that these defects could be a kind of intrinsic defect in thequasicrystals. PACS: 61. 72. Ef, 61. 72. Dd, 61. 44. Br

Quantitative x-ray topographic analysis of the defects of 6H-SiC single crystals and homoepitaxial silicon carbide

Planar dislocation pileups (PDPs) and curvilinear dislocation segments (CDSs) are considered as indicators of the local elastic shear stress fields (LESSFs) that existed in the growing single crystals at the time of stabilization of their dislocation structure. Calculations using the theory of dislocations with the experimental parameters of PDPs and CDSs measured from the x-ray topograms (taken by the Lang and divergent-polychromatic-beam (DPB) methods) give values of the LESSFs in the range (0.2–1.5)×106 Pa for thin single-crystal wafers of SiC (6H) grown by sublimation in a graphite container. A strong nonuniform bending of the single-crystal wafers is observed; for the x-ray topographic study of the dislocation structure in these wafers the DPB method is preferable to the Lang method on account of its low sensitivity to bending.