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Spatial Prediction of Soil Aggregate Stability and Aggregate-Associated Organic Carbon Content at the Catchment Scale Using Geostatistical Techniques

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Pedosphere 2011年第3期21卷 389-399页

作者： J.mOhAmmADI m.h.motaghian Department of Soil Science Agriculture CollegeShahrekord University

The association of organic carbon with secondary particles （aggregates） results in its storage and retention in soil. A study was carried out at a catchment covering about 92 km2 to predict spatial variability of soil water-stable aggregates （WSA）, mean weight diameter （mWD） of aggregates and organic carbon （OC） content in macro.- （〉 2 mm）, meso- （1-2 mm）, and micro-aggregate （〈 1 mm） fractions, using geostatistical methods. One hundred and eleven soil samples were eSlleeted at the 0 10cm depth and fractionated into macro-, meso-, and mlcro-aggregates by wet sieving. The OC content was determined for each fraction. A greater percentage of water-stable aggregates was found for micro-aggregates, followed by meso-aggregates. Aggregate OC content was greatest in meso-aggregates （9 g kg-1）, followed by micro-aggregates （7 g kg-1）, while the least OC content was found in macro-aggregates （3 g kg-1）. Although a significant effect （P = 0.000） of aggregate size on aggregate OC content was found, however, our findings did not support the model of aggregate hierarchy. Land use had a significant effect （P = 0.073） on aggregate OC content. The coefficients of variation （CVs） for OC contents associated with each aggregate fraction indicated macro-aggregates as the most variable （CV = 71%）. Among the aggregate fractions, the micro-aggregate fraction had a lower CV value of 27%. macro-aggregates to 84% for micro-aggregates. Geostatistical analysis differences in their spatial patterns in both magnitude and space at variance for most aggregate-associated properties was lower than 45%. The mean content of WSA ranged from 15% for showed that the measured soil variables exhibited each aggregate size fraction. The relative nugget The range value for the variogram of water-stable aggregates was almost similar （about 3 km） for the three studied aggregate size classes. The range value for the variogram of aggregate-associated OC contents ranged from about 3 km for macro-aggregates to about

关键词： kriging organic matter variogram water-stable aggregates

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Spatial Estimation of Saturated hydraulic Conductivity from Terrain Attributes Using Regression,Kriging,and Artificial Neural Networks

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Pedosphere 2011年第2期21卷 170-177页

作者： h.R.motaghian J.mOhAmmADI Department of Soil Science Agriculture CollegeShahrekord UniversityShahrekord (Iran)

Several methods,including stepwise regression,ordinary kriging,cokriging,kriging with external drift,kriging with varying local means,regression-kriging,ordinary artificial neural networks,and kriging combined with artificial neural networks,were compared to predict spatial variation of saturated hydraulic conductivity from environmental *** methods except ordinary kriging allow for inclusion of secondary *** secondary spatial information used was terrain attributes including elevation,slope gradient,slope aspect,profile curvature and contour curvature.A multiple jackknifing procedure was used as a validation *** mean square error (RmSE) and mean absolute error (mAE) were used as the validation indices,with the mean RmSE and mean mAE used to judge the prediction *** performance by ordinary kriging was poor,indicating that prediction of saturated hydraulic conductivity can be improved by incorporating ancillary data such as terrain *** combined with artificial neural networks performed *** prediction models made better use of ancillary information in predicting saturated hydraulic conductivity compared with the competing *** combination of geostatistical predictors with neural computing techniques offers more capability for incorporating ancillary information in predictive soil *** is great potential for further research and development of hybrid methods for digital soil mapping.

关键词： digital elevation model geostatistics soil hydraulic properties spatial mapping

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Application of Kinetic models in Describing Soil Potassium Release Characteristics and Their Correlations with Potassium Extracted by Chemical methods

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Pedosphere 2013年第4期23卷 482-492页

作者： A. R. hOSSEINPUR h. R. motaghian Department of Soil Science College of Agriculture Shahrekord University

Potassium （K） release characteristics in soil play a significant role in supplying available K. Information on K-release characteristics in soils of central Iran is limited. The objectives of this study were to determine K release characteristics and correlations of K release rate constants with K extracted by different chemical methods in surface soils of ten calcareous soils of central Iran. The kinetics of K release in the soils was determined by successive extraction with 0.01 mol L-1 CaC12 in a period of 2-2017 h at 25±1℃. Soil K was extracted by distilled water, 0.5 mol L-1 mgNO3, 0.002 mol L-1 SrC12, 0.1 mol L-1 BaC12, 0.01 mol L-1 CaC12, 1 mol L-1 NaC1, 1 mol L-1 boiling hNO3, 1 mol L-1 Nh4OAC, mehlich 1, 0.002 mol L-1 SrC12 ＋ 0.05 mol L-1 citric acid, and ammonium bicarbonate-diethylenetriamine pentaacetic acid （AB-DTPA）. A plot of cumulative amounts of K released showed a discontinuity in slope at 168 h. Thus, two equations were applied to two segments of the total reaction time （2-168 and 168-2 017 h）. Cumulative amounts of K released ranged from 55 to 299 mg kg-1 in 2-168 h and from 44 to 119 mg kg-1 in 168-2 017 h. Release kinetics of K in the two time segments conformed fairly well to parabolic diffusion, simplified Elovich, and power function models. There was a wide variation in the K release rate constants. Increasingly higher average concentrations of soil K were extracted by distilled water, mehlich 1, SrC12, CaC12, SrC12 ＋ citric acid, AB-DTPA, mgNO3, NaCI, Nh4OAc, BaCI2, and hNO3. Potassium release rate constants were significantly correlated with K extracted. The results of this study showed that information obtained from mathematical modeling in two reaction time segments can help to estimate the K-supplying power of soils.

关键词： chemical extraction calcareous soils mathematical modeling release rate constant time segments

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Refining Soil Organic matter Determination by Loss-on-Ignition

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Pedosphere 2011年第4期21卷 473-482页

作者： m.h.SALEhI O.hAShEmI BENI h.BEIGI hARChEGANI I.ESFANDIARPOUR BORUJENI h.R.motaghian Department of Soil Science College of AgricultureShahrekord University Department of Soil Science College of AgricultureVali-e-Asr University

Wet oxidation procedure,i.e.,Walkley-Black (WB) method,is a routine,relatively accurate,and popular method for the determination of soil organic matter (SOm) but it is time-consuming,costly and also has a high potential to cause environmental pollution because of disposal of chromium and strong acids used in this ***,loss-on-ignition (LOI) procedure,a simple and cheap method for SOm estimation,which also avoids chromic acid wastes,deserves more *** aims of this research were to study the statistical relationships between SOm determined with the LOI (SOmLOI) and WB (SOmWB) methods to compare the spatial variability of SOm in two major plains,Shahrekord and Koohrang plains,of Chaharmahal-va-Bakhtiari Province,*** surface soil samples (0-25 cm) were randomly collected in each plain to determine SOm using the WB method and the LOI procedure at 300,360,400,500 and 550 ℃ for 2 *** samples covered wide ranges of soil texture and calcium carbonate equivalent (CCE).The general linear form of the regression equation was calculated to estimate SOm LOI from SOm obtained by the WB method for both overall samples and individual *** soil samples were also randomly selected to compare the SOm and CCE before and after ignition at each *** accuracy of the continuous maps generated for the LOI and WB methods was considered to determine the accordance of two *** showed a significant positive linear relationship between SOm LOI and SOm *** of determination (R2) of the equations for individual plains were higher than that of the overall *** of determination and line slopes decreased and root mean square error (RmSE) increased with increasing ignition temperature,which may be due to the mineral structural water loss and destruction of carbonates at higher temperatures.A temperature around 360 ℃ was identified as optimum as it burnt most organic carbon,destroyed less inorganic carbon,cau

关键词： calcium carbonate equivalent ignition temperature kriged maps spatial variability wet oxidation

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Geostatistical Assessment of the Spatial Distribution of Some Chemical Properties in Calcareous Soils

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Journal of Integrative Agriculture 2012年第10期11卷 1729-1737页

作者： Asma Najafian mahmood Dayani hamid Reza motaghian habibolah Nadian Department of Soil Sciences College of Agriculture Shiraz University Shiraz *** 1ran Department of Soil Sciences Khouzestan Ramin University of Agriculture and Natural Resources Ahwaz *** Iran Department of Soil Science Faculty of Agriculture Shahrekord University Shahrekord *** Iran

Spatial patterns of soil fertility parameters and other extrinsic factors need to be identified to develop farming practices that match agricultural inputs with local crop needs. Little is known about the spatial structure of nutrition in Iran. The present study was conducted in a 132-ha field located in central Iran. Soil samples were collected at 0-30 cm depth and were then analyzed for total nitrogen （N）, available phosphorus （P）, available potassium （K）, available copper （Cu）, available zinc （Zn）, available iron （Fe） and available manganese （mn）. The results showed that the contents of soil organic matter, Cu and Zn in marvdasht＇s farms were low. The spatial distribution model and spatial dependence level for soil chemical properties varied in the field. N, K, carbonate calcium equivalent （CaCO3） and electrical conductivity （EC） data indicated the existence of moderate spatial dependence. The variograms for other variables revealed stronger spatial structure. The results showed a longer range value for available P （480 m）, followed by total N （429 m）. The value of other chemical properties values showed a shorter range （128 to 174 m）. Clear patchy distribution of N, P, K, Fe, mn, Cu and Zn were found from their spatial distribution maps. This proved that sampling strategy for estimating variability should be adapted to the different soil chemical properties and field management. Therefore, the spatial variability of soil chemical properties with strong spatial dependence could be readily managed and a site-specific fertilization scheme for precision farming could be easily developed.

关键词： geostatistics kriging spatial variability precision farming

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Effects of sugarcane residue biochar and P fertilizer on P availability and its fractions in a calcareous clay loam soil

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Biochar 2020年第3期2卷 357-367页

作者： mina Safian hamidreza motaghian Alireza hosseinpur Department of Soil Science College of AgricultureShahrekord UniversityShahrekordIran

Biochar has the potential to affect the cycle of phosphorus(P),but the underlying mechanisms of its effects remain poorly understood in calcareous *** understanding of the effects of biochar is limited in calcareous soils during ***,this study was conducted to investigate how the availability and mineral fractions of P change after the addition of combined biochar and P fertilizer during incubation in calcareous *** residue(raw SR)and biochar(400℃for 2 h)were added to soils treated with 50 mg kg−1 of P,in the form of Ca(h_(2)PO_(4))_(2)·h_(2)O,at 0.5 and 1%(w/w).The soils were incubated at 25±1℃for 120 *** P(Olsen P)contents and mineral P fractions were measured after various incubation times(7,30,90,and 120 days).Biochar addition remarkably increased the amount of available P when compared with the raw SR treatment and the control condition(Phe amount of available P in the soils decreased and remained unchanged *** results indicated that the addition of 50 mg kg−1 of P as fertilizer significantly augmented the labile P and P associated with Fe and Al in all the treatments at all incubation times(Pmparison with P treated with raw SR,P associated with Fe and Al was significantly enhanced after biochar addition(Ph labile P and P associated with Fe and *** found that biochar addition could increase available pools,thus improving available P concentrations at various incubation ***,we conclude that sugarcane residue biochar can enhance the available P in calcareous soils.

关键词： Organic amendment Incubation time Available pool

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The sexually dimorphic expression of glutamate transporters and their implication in pain after spinal cord injury

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Neural Regeneration Research 2025年第11期20卷 3317-3329页

作者： Jennifer m.Colón-mercado Aranza I.Torrado-Tapias Iris K.Salgado Jose m.Santiago Samuel E.Ocasio Rivera Dina P.Bracho-Rincon Luis h.Pagan Rivera Jorge D.miranda Department of Physiology University of Puerto RicoMedical Sciences CampusSan JuanPRUSA National Institutes of health National Human Genome Research InstituteBethesdaMDUSA Universidad Central del Caribe School of MedicineBayamónPRUSA University of Puerto Rico Carolina CampusCarolinaPRUSA Institute of Neurobiology San JuanPRUSA

In addition to the loss of motor function,~60% of patients develop pain after spinal cord *** cellular-molecular mechanisms are not well understood,but the data suggests that plasticity within the rostral,epicenter,and caudal penumbra of the injury site initiates a cellularmolecular interplay that acts as a rewiring mechanism leading to central neuropathic *** can lead to the formation of new connections triggering abnormal sensory *** excitatory glutamate transporters are responsible for the reuptake of extracellular glutamate which makes them a critical target to prevent neuronal hyperexcitability and *** previous studies showed a sexually dimorphic therapeutic window for spinal cord injury after treatment with the selective estrogen receptor modulator *** this study,we investigated the anti-allodynic effects of tamoxifen in male and female rats with spinal cord *** hypothesized that tamoxifen exerts anti-allodynic effects by increasing the expression of glutamate transporters,leading to reduced hyperexcitability of the secondary neuron or by decreasing aberrant *** and female rats received a moderate contusion to the thoracic spinal cord followed by subcutaneous slow-release treatment of tamoxifen or matrix pellets as a control(placebo).We used von Frey monofilaments and the“up-down method”to evaluate mechanical *** treatment decreased allodynia only in female rats with spinal cord injury revealing a sexdependent *** expression profile of glutamatergic transporters(excitatory amino acid transporter 1/glutamate aspartate transporter and excitatory amino acid transporter 2/glutamate transporter-1)revealed a sexual dimorphism in the rostral,epicenter,and caudal areas of the spinal cord with a pattern of expression primarily on *** rodents showed a significantly higher level of excitatory amino acid transporter-1 expression while male rodents showed increased

关键词： allodynia central neuropathic pain EAAT-1/GLAST EAAT-2/GLT-1 glutamate transporters selective estrogen receptor modulator sexual dimorphism spinal cord injury trauma

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Free vibration and buckling analysis of polymeric composite beams reinforced by functionally graded bamboo fbers

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Applied mathematics and mechanics(English Edition) 2024年第3期45卷 543-562页

作者： h.m.FEIZABAD m.h.YAS Department of mechanical Engineering Razi UniversityKermanshah ***Iran

Natural fibers have been extensively researched as reinforcement materials in polymers on account of their environmental and economic advantages in comparison with synthetic fibers in the recent *** fibers are renowned for their good mechanical properties,abundance,and short cycle *** beams are one of the fundamental structural components and are susceptible to mechanical loads in engineering applications,this paper performs a study on the free vibration and buckling responses of bamboo fiber reinforced composite(BFRC)beams on the elastic *** different functionally graded(FG)layouts and a uniform one are the considered distributions for unidirectional long bamboo fibers across the *** elastic properties of the composite are determined with the law of *** hamilton’s principle,the governing equations of motion are *** generalized differential quadrature method(GDQm)is then applied to the equations to obtain the *** achieved outcomes exhibit that the natural frequency and buckling load values vary as the fiber volume fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam ***,a comparative study is conducted between the derived analysis outcomes for BFRC and homogenous polymer beams to examine the effectiveness of bamboo fibers as reinforcement materials,demonstrating the significant enhancements in both vibration and buckling responses,with the exception of natural frequencies for cantilever beams on the Pasternak foundation with the FG-◇fiber ***,the obtained analysis results of BFRC beams are also compared with those for carbon nanotube reinforced composite(CNTRC)beams found in the literature,indicating that the buckling loads and natural frequencies of BFRC beams are lower than those of CNTRC beams.

关键词： bamboo fiber free vibration buckling analysis functionally graded(FG)beam elastic foundation generalized differential quadrature method(GDQm)

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Analytical model for thermal lensing and spherical aberration in diode side-pumped Nd:YAG laser rod having Gaussian pump profile

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Chinese Physics B 2015年第12期24卷 334-341页

作者： m h moghtader Dindarlu m Kavosh Tehrani h Saghafifar A maleki Institute of Optics and Laser Malek-Ashtar University of Technology

In this paper, according to the temperature and strain distribution obtained by considering the Gaussian pump profile and dependence of physical properties on temperature, we derive an analytical model for refractive index variations of the diode side-pumped Nd：YAG laser rod. Then we evaluate this model by numerical solution and our maximum relative errors are 5% and 10% for variations caused by thermo–optical and thermo–mechanical effects; respectively. Finally, we present an analytical model for calculating the focal length of the thermal lens and spherical aberration. This model is evaluated by experimental results.

关键词： side-pumped laser rod Gaussian pump profile thermal effects thermal lens spherical aberration

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microstructure evolution of a recycled Al-Fe-Si-Cu alloy processed by tube channel pressing

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International Journal of minerals,metallurgy and materials 2018年第10期25卷 1166-1172页

作者： m.h.Farshidi m.Rifai h.miyamoto Department of materials Science and metallurgical Engineering Ferdowsi University of Mashhad Department of mechanical Engineering Doshisha University

Although excellent recyclability is one of the advantages of Al alloys, a recycling process can reduce different properties of these alloys by adding coarse AlFeSi particles into the alloys' microstructures. One of the well-known methods for modifying the microstructure of metallic materials is the imposition of severe plastic deformation(SPD). Nevertheless, the microstructure evolutions of recycled Al alloys containing extraordinary fractions of AlFeSi particles during SPD processing have seldom been considered. The aim of the present work is to study the microstructure evolution of a recycled Al–Fe–Si–Cu alloy during SPD processing. For this purpose, tubular specimens of the mentioned alloy were subjected to different numbers of passes of a recently developed SPD process called tube channel pressing(TCP); their microstructures were then studied using different techniques. The results show that coarse AlFeSi particles are fragmented into finer particles after processing by TCP. however, decomposition and dissolution of AlFeSi particles through TCP processing are negligible. In addition, TCP processing results in an increase in hardness of the alloy, which is attributed to the refinement of grains, to an increase of the dislocation density, and to the fragmentation of AlFeSi particles.

关键词： AlFeSi intermetallic particle severe plastic deformation microstructure tube channel pressing

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