bluuebunny/crossref_metadata_2025 huggingface dataset:
Meta‐analysis: abundance, behavior, and hydraulic energy shape biotic effects on sediment transport in streams
Authors: Albertson L. K. , Allen D. C.
Published: November 2014

An increasing number of studies have emphasized the need to bridge the disciplines of ecology and geomorphology. A large number of case studies show that organisms can affect erosion, but a comprehensive understanding of biological impacts on sediment transport conditions is still lacking. We use meta‐analysis to synthesize published data to quantify the effects of the abundance, body size, and behavior of organisms on erosion in streams. We also explore the influence of current velocity, discharge, and sediment grain size on the strength of biotic effects on erosion. We found that species that both increase erosion (destabilizers) and decrease erosion (stabilizers) can alter incipient sediment motion, sediment suspension, and sediment deposition above control conditions in which the organisms were not present. When abundance was directly manipulated, these biotic effects were consistently stronger in the higher abundance treatment, increasing effect sizes by 66%. Per capita effect size and per capita biomass were also consistently positively correlated. Fish and crustaceans were the most studied organisms, but aquatic insects increased the effect size by 550× compared to other types of organisms after accounting for biomass. In streams with lower discharge and smaller grain sizes, we consistently found stronger biotic effects. Taken collectively, these findings provide synthetic evidence that biology can affect physical processes in streams, and these effects can be mediated by hydraulic energy. We suggest that future studies focus on understudied organisms, such as biofilms, conducting experiments under realistic field conditions, and developing hypotheses for the effect of biology on erosion and velocity currents in the context of restoration to better understand the forces that mediate physical disturbances in stream ecosystems.
Crop Yields and Soil Nutrients in Response to Long‐Term Fertilization in a Desert Oasis
Authors: Yang Rong , Su Yongzhong , Yang Qin
Published: November 2014

Knowledge of the effect of long‐term fertilizer application on arable lands reclaimed from the desert in arid regions is limited. In this study, we used data obtained from a 7‐yr field experiment to determine the effect of different fertilizer application strategies on crop yields and soil nutrient status in a desert oasis of northwest China. Our results showed that integrated fertilizer application (IFA) treatments produced average maize (Zea maysL.) and soybean [Glycine max(L.) Merr.] yields 10.3 and 13.3% greater than those under chemical fertilizer application (CFA) treatments and 56.0 and 7.3% greater than those under organic manure application (OMA) treatment. With one exception for a K treatment, the average grain yield during the 7 yr of the study tended to increase with increased nutrient rates, and reached the maximum value at a 281 kg ha−1N, 171 kg ha−1P2O5, and 544 kg ha−1K2O input level. At the end of the study, soil organic matter (SOM) and total N were the highest in the soil treated with OMA, followed by those treated with IFA and then CFA. High CFA rates increased soil phosphorus levels. The crop yield values linearly increased with the increase in SOM, total N, available N, and available K. Our findings suggested that in the desert oasis ecosystem, an IFA system increased both crop yields and soil nutrients.
Screening Alfalfa for Salt Tolerance Based on Lipid Peroxidation and Antioxidant Enzymes
Authors: Ashrafi Ensieh , Razmjoo Jamshid , Zahedi Morteza , Pessarakli Mohammad
Published: November 2014

In an effort to assess salt tolerance of alfalfa (Medicago sativa L.), herbage yield, leaf ascorbate peroxidase (APX), catalase (CAT), and peroxidase (POX) activities and malondialdehyde (MDA) content were measured in nine alfalfa cultivars grown in the field. Plants were grown under 20 (control), 60, and 120 mM NaCl salinity in Isfahan, Iran during 2010 to 2013. Based on correlation coefficients among the measured traits under salt‐stress levels, MDA content had the highest correlation with herbage yield followed by CAT and POX activities, respectively. Based on the reduction in herbage yield, under 120 mM NaCl stress, Isfahani and Rehnani were the most salt tolerant, while Bami, Pioneer, and Nikshahri were the most sensitive cultivars. According to the relation between the salt tolerance and the measured traits, MDA content (r = 0.93) was the most important marker for salt tolerance followed by CAT (r = 0.58) and POX (r = 0.53) activities, respectively. However, the relationship between salt tolerance and antioxidant enzymes activities was not as strong as that for MDA, and MDA content was well correlated with salt tolerance. Given the simplicity of MDA content measurement and the complexity of extractions and assays of the enzymes, CAT, APX, and POX activities may not be used as markers, whereas, MDA content would be a much better indicator for assessing salt‐tolerant cultivars in alfalfa.
Identify Physiological Markers for Drought Tolerance in Alfalfa
Authors: Maghsoodi Malek , Razmjoo Jamshid
Published: November 2014

Physiological markers may provide a shortcut for identifying drought tolerance in alfalfa (Medicago sativa L.). Thus, the objective of this study was to understand physiological properties of alfalfa to assess drought tolerance of its cultivars. Ten alfalfa cultivars (Qomi, Isfahani, Hamedani, Bami, Ordobadi, Gharayonje, Nikshahri, Yazdi, Baghdadi, and Cody) and four irrigation regimes (55, 65, 75, and 85% depletion of available soil water) were arranged as split plot in a completely randomized block design with three replications to determine the chlorophyll, carotenoid, soluble sugars, proline, relative water contents, and herbage yield response of alfalfa cultivars to drought stress. Physiological and herbage yield traits were drought level‐cultivar‐specific and discriminated the cultivars based on their drought tolerance. Based on the correlation between drought tolerance and measured traits at the highest drought level, carotenoid content (r = 0.94), was the most important marker followed by relative water content (r = 0.92) and soluble sugars content (r = 0.89), respectively, and Baghdadi was the most drought tolerant cultivar. The results showed that the physiological markers may be used to identify alfalfa germplasms for drought tolerance.
Switchgrass Establishment and Biomass Yield Response to Seeding Date and Herbicide Application
Authors: Sadeghpour Amir , Hashemi Masoud , DaCosta Michelle , Gorlitsky Leryn E. , Jahanzad Emad , Herbert Stephen J.
Published: November 2014

Weed interference is a major challenge in the establishment of switchgrass (Panicum virgatum L.). A field experiment was conducted in 2011–2012 and 2012–2013 growing seasons to study the response of switchgrass to seeding date (November, May, June, and July) combined with pre‐emergence (PRE) application of atrazine (A) [6‐chloro‐N‐ethyl‐N’‐(1‐methylethyl)‐1,3,5‐triazine‐2.4‐dimine] and quinclorac (Q), or PRE A+Q followed by post‐emergence (POST) application of 2,4‐D ([2,4‐dichlorophenoxy] acetic acid) and dicamba dicamba (3,6‐dichloro‐o‐anisic acid). Switchgrass tiller density was increased with delaying the seeding date until July (194 tiller m−2) in 2012; however, no significant differences in tiller density were observed among seeding dates in 2013. Switchgrass was more morphologically developed (plant height and adventitious root numbers) at earlier seeding dates (November and May) compared with later seeding dates. Weed biomass was reduced by 18% as a result of application of PRE A+Q followed by POST compared with PRE A+Q treatment. The highest weed biomass was recorded from May seeding date in both years. The highest switchgrass biomass yield was consistently obtained from May (0.87 and 1.38 Mg ha−1 in 2012 and 2013, respectively) and June seeding dates (0.66 and 1.22 Mg ha−1 in 2012 and 2013, respectively). Our results suggested that although higher tiller density and lower weed biomass was observed with later planting date, switchgrass was more morphologically developed and produced higher biomass yield when seeded earlier. To ensure a successful long‐term switchgrass establishment an early seeding date (May) and application of PRE A+Q followed by POST 2,4‐D and dicamba could be a sustainable management practice.
Influence of Long‐Term Application of Manure Type and Bedding on Yield, Protein, Fiber, and Energy Value of Irrigated Feed Barley
Authors: Miller J. J. , Beasley B. W. , Drury C. F. , Larney F. J. , Hao X.
Published: November 2014

The long‐term effect of land application of manure type (composted [CM] vs. stockpiled [SM] manure), bedding (wood‐chips [WD] vs. straw [ST]), and application rate on yield, protein, fiber, and energy value of feed barley (Hordeum vulgare L.) for beef cattle (Bos taurus) is unknown. Dry matter yield and feed quality of irrigated feed barley was measured on a clay loam soil after 5 (2002), 8 (2005), and 12 yr (2009) of annual applications of CM or SM feedlot manure with WD or ST bedding at three application rates (13, 39, 77 Mg ha−1 dry wt.). The treatments also included an unamended control and inorganic fertilizer treatment. Mean yields in 2005 were significantly (P ≤ 0.05) greater for CM–ST than SM–WD but CM–ST was similar to SM–ST and CM–WD. Yields in 2009 were significantly lower for CM–WD compared to the other three treatments, and were greater for ST‐13 and WD‐77 compared to WD‐13. Crude protein was greater for SM than CM when averaged over the 3 yr. Bedding influenced crude and soluble protein but the effects depended on interactions with rate and year. For example, crude and soluble protein in 2009 was greater for ST than WD at the 39 and 77 Mg ha−1 rates. Manure type and bedding may be practices to manage feed barley yield and protein, but will likely have little or no effect on the fiber content and energy value of the feed.
Proline Accumulation Is Not Correlated with Saline‐Alkaline Stress Tolerance in Rice Seedlings
Authors: Lv Bing‐Sheng , Ma Hong‐Yuan , Li Xiao‐Wei , Wei Li‐Xing , Lv Hai‐Yan , Yang Hao‐Yu , Jiang Chang‐Jie , Liang Zheng‐Wei
Published: November 2014

Proline accumulation is a common physiological response of plants to various environmental stresses. However, the physiological importance of proline accumulation in stress tolerance remains controversial. Here, we examined whether proline accumulation in rice (Oryza sativa L.) seedlings is correlated with tolerance to saline–alkaline stress factors, namely, salt, alkaline and osmotic stresses, by using 25 japonica cultivars. The tolerance of seedlings to each stress treatment varied significantly among the cultivars as evaluated by membership degree (MD) of fuzzy set theory on the basis of changes in shoot length (SL), total root length (TRL), total root surface area (RSA), average root diameter (RD), total root volume (RV), and root numbers (RN), after 6 d of stress treatment. The proline levels in all the japonica cultivars increased significantly in response to the investigated stresses. However, partial correlation analysis showed no significant correlations between the basal or elevated proline levels and tolerance to any of the investigated stress factors. These findings suggest that proline accumulation levels do not serve as reliable parameters for assessing saline–alkaline stress tolerance in rice. On the other hand, several root growth indices of rice seedlings, namely TRL, RSA, RD, RV, and RN, showed good correlations with the investigated stress tolerance, and therefore, represent a useful set of growth parameters for assessing saline‐alkaline stress tolerance in rice.
Growth Variability of Italian Weedy Rice Populations Grown with or without Cultivated Rice
Authors: Andres André , Fogliatto Silvia , Ferrero Aldo , Vidotto Francesco
Published: November 2014

Weedy rice (Oryza sativa L.) exhibits a great variability of morphological traits. To detect if this variability can affect its growth behavior, two experiments were performed on 10 Italian weedy rice populations grown as pure stand and in competition with rice. Five awnless and five awned populations were grown in field conditions in 15‐L pots. In the pure stand experiment, each pot hosted a single plant of weedy rice, while in the competition experiment the weedy rice plant was surrounded by 10 plants of cultivar Sirio CL. Plant height, tiller, and leaf numbers were recorded six times during the growing season. In competition, leaf area, culm weight, and leaf weight were also assessed. In pure stand, no significant differences between awned and awnless groups were found for all the considered parameters. Differences were found in plant height (from 70.7 to 91.9 cm) and leaf weight (from 5.64 to 9.85 g plant−1) among awned populations only. In competition, weedy rice showed lower and more variable growth indices. The least and most affected growth variables were plant height (16% of average reduction in comparison with pure stand) and leaf weight (70.3% of average reduction), respectively. Awned populations showed higher and more variable values of growth parameters, suggesting a stronger competitiveness and a wider phenotypic plasticity. Knowledge of growth behavior related to weedy rice variability could improve modeling of infestation dynamics and highlights the need of an integrated weed management approach.
Surfactant Application on Yield and Irrigation Water Use Efficiency in Corn under Limited Irrigation
Authors: Chaichi Mohammad R. , Nurre Paul , Slaven Jeff , Rostamza Mina
Published: November 2014

Drought, and rising water and pumping costs dictate that continued production of corn (Zea mays L.) will be limited in future years if effective water conservation strategies are not established. This study was conducted to evaluate the effect of irrigation regimes in conjunction with surfactant treatments on field corn grain yield (GY), total dry matter (TDM) production, and irrigation water use efficiencies (IWUE) based on GY and TDM in a distinct Mediterranean climate, at Spadra Ranch in Pomona, CA, for 2 yr (2008 and 2009). The field experiment was set up in a split plot design with four replications where irrigation regimes (I40: 40%, I60: 60%, I80: 80%, and I100: 100% of the estimated evapotranspiration) was the main plot and application of surfactant (water treated with surfactant and no surfactant application) was assigned to the subplot. The results showed a stepwise reduction in TDM and GY in treatments both with and without surfactant as water deficit increased. However, surfactant application at any irrigation level resulted in higher GY and TDM compared to no‐surfactant treatments. Irrigation water use efficiency based on TDM and GY was the highest in I40 and the lowest in full irrigation (I100) conditions. By application of surfactant in irrigation water, both IWUE and GY increased. Surfactant application increased irrigation costs by 4.7%; however, it increased profit by 19.75%. Economic evaluation showed that the grain yield increment could compensate surfactant price and consequently the same profit achieved with applying 40% less water plus surfactant compared with 100% crop evapotranspiration with no surfactant application. In a Mediterranean climate and under limited irrigation conditions, corn could be cultivated with acceptable yields by application of surfactant.
Efficiency of Plant Breeding
Authors: Ceccarelli Salvatore
Published: November 2014

Participatory plant breeding (PPB) has been practiced for several reasons, including sociological, humanitarian, and egalitarian. This paper aims to demonstrate that PPB should be practiced simply because it increases plant breeding efficiency, which is defined as (i) the ratio between the number of varieties adopted and the number of crosses made, (ii) the response to selection, and (iii) the benefit/cost ratio, not only as often done by public breeding programs, by the number of varieties released by public breeding programs. After reviewing the reasons for the lack of adoption of several of the varieties released, and the theoretical basis justifying the use of correlated response to measure selection gains, the issue of the benefit/cost ratio is discussed within the context of adoption rates. The assumption is that without adoption, no benefit will occur. Ways to increase the three measures of breeding efficiency are discussed in detail, and the conclusion is made that the three measures can be increased by combining decentralized selection with farmers’ participation in a PPB program. The essential features of a PPB program are reviewed, including the experimental designs and statistical analysis used to increase the precision of on‐farm trials. The findings show that PPB increases breeding efficiency, both in terms of response to selection measured over the time from the initial cross to adoption and in terms of the benefit/cost ratio as a consequence of a higher adoption rate. In a PPB program, adoption starts during the process of selection and precedes variety release. In a conventional plant breeding (CPB) program, the sequence is reversed. Other differences between a PPB and a CPB program include the increase of agrobiodiversity, which in a PPB program is higher because of the rapid spatiotemporal turnover of varieties, and because the seed of new varieties is readily available to farmers, thus contributing to food security. Because of its decentralized nature, PPB can accommodate organic farms and become easily adopted by both national and international public breeding programs as one way of adapting crops to climate changes.
Numerical Study of Prepolarized Surface Nuclear Magnetic Resonance in the Vadose Zone
Authors: de Pasquale Giulia , Mohnke Oliver
Published: November 2014

Surface nuclear magnetic resonance (SNMR) is a geophysical technique for water exploration in the shallow subsurface. To investigate the vadose zone, it is necessary to increase the method sensitivity; therefore we developed a new approach for SNMR experiments. Adapted from laboratory applications, an artificial static magnetic prepolarizing (Px) field is superimposed on the Earth's magnetic field to enhance the equilibrium magnetization of the pore water and thus to increase the SNMR sounding signals. We numerically investigated the basic feasibility of this approach by modeling the relevant static and oscillating magnetic fields and resulting SNMR responses. Configuration parameters, e.g., current intensities, loop sizes, and layouts, were optimized by numerical simulations. The most feasible field layouts comprised two Px loops symmetrically arrayed with respect to the transmitter/receiver (Tx/Rx) antennae or a single Px loop with its radius approximately three times larger than the respective Tx/Rx loops, thus yielding a 10‐fold increase of the recorded signals compared with conventional SNMR. Eventually, we simulated synthetic sounding curves obtained from a water body layer at various depths and thicknesses, concluding that in the shallowest subsurface, the use of two loops to enhance the signal is more effective than a single antenna, but the results deteriorate for deeper water layers.
Effects of Lime and Concrete Waste on Vadose Zone Carbon Cycling
Authors: Thaysen E.M. , Jessen S. , Postma D. , Jakobsen R. , Jacques D. , Ambus P. , Laloy E. , Jakobsen I.
Published: November 2014

In a series of mesocosm experiments, with barley (Hordeum vulgare L.) grown on podzolic soil material, we have investigated inorganic carbon cycling through the gaseous and liquid phases and how it is affected by different soil amendments. The mesocosm amendments comprised the addition of 0, 9.6, or 21.2 kg m−2 of crushed concrete waste (CCW) or 1 kg lime m−2. The CCW and lime treatments increased the dissolved inorganic carbon (DIC) percolation flux by about 150 and 100%, respectively, compared to the controls. However, concurrent increases in the CO2 efflux to the atmosphere (ER) were more than one order of magnitude higher than increases in the DIC percolation flux. Analysis of soil solutions, coupled reactive‐transport modeling studies, and a decrease in soil carbonate contents over the experiment altogether suggested that the increased ER from amended mesocosms was derived from the carbonate contained in the amendments, which, hence, mostly escaped to the atmosphere. Our results are important in the context of climate change due to the widespread application of lime to acidic soils. The CCW amendment had no adverse effects on plant growth and groundwater quality.
Evaluation of the marine alga Sargassum glaucescens for the adsorption of Zn(II) from aqueous solutions
Authors: Esmaeili Akbar , Darvish Mayam
Published: November 2014

The objective of this research was to study the efficacy of the marine brown alga Sargassum glaucescens in batch removal of Zn(II) from wastewater and seawater. For these experiments, a dried biomass was used to adsorb Zn(II) from aqueous solutions. The effects of varying pH, biomass weight, retention time and initial concentration of Zn(II) were studied. The maximum efficiency of Zn(II) removal obtained was 90.00%. The experimental adsorption data were fitted to the Freundlich adsorption model. A pseudo-second-order model was found to offer the best analysis of Zn(II) uptake. Kinetic studies showed that a biomass formed of marine-dried S. glaucescens exhibited high biosorption capacity. A solution pH of 5.0 was found to be optimal for adsorption. Results showed that removal of Zn(II), increased to 90.00% with increasing contact time, increasing pH (to 5.0) and decreasing adsorbent amount. The equilibrium adsorption data are fitted to the Freundlich isotherm model and pseudo-second-order kinetic models. Therefore, brown algae Sargassum glaucescens was an economical adsorbent.
Inhibition of nitrate and the accumulated denitrification intermediate (nitrite) on perchlorate bioreduction
Authors: Wang Rui , Chen Liang , Liu Fei , Chen Hong H. , Zhang Jia W. , Chen Ming
Published: November 2014

Bioreduction of perchlorate and nitrate by perchlorate-reducing microorganisms (PRMs) is an environmentally friendly, economic, and efficient technology to treat mixed plumes composed of these substances. The influence of perchlorate, nitrate, and denitrification intermediates on PRM activity is a critical factor, which may affect the efficiency of treatment technology. This study investigated the inhibition of nitrate and the intermediate (nitrite) accumulated during the denitrification process on perchlorate bioreduction via a batch-type experiment. From the experiment, it was found that perchlorate had no effect on the denitrification process and that the reduction rate of perchlorate could be improved when NO3−-N/ClO4− ≤1.2. However, a negative effect of nitrate on perchlorate reduction was observed when NO3−-N/ClO4− >1.2 with an accumulation of 18.0 mg NO2−-N /L. This negative effect increased with the concentration of nitrate. Moreover, nitrite from the denitrification process had a similar negative effect on perchlorate reduction. Bioreduction of perchlorate was not started until nitrite was totally reduced, and a 2–13 day lag period was observed for perchlorate reduction after nitrite depletion.
Applying the Soil Water Assessment Tool to 5th Canadian Division Support Base Gagetown
Authors: Burdett Shawn , Hulley Michael , Smith Andy
Published: November 2014

A hydrologic and water quality model is sought to establish an approach to land management decisions for a Canadian Army training base. Training areas are subjected to high levels of persistent activity creating unique land cover and land-use disturbances. Deforestation, complex road networks, off-road manoeuvres, and vehicle stream crossings are among major anthropogenic activities observed to affect these landscapes. Expanding, preserving and improving the quality of these areas to host training activities for future generations is critical to maintain operational effectiveness. Inclusive to this objective is minimizing resultant environmental degradation, principally in the form of hydrologic fluctuations, excess erosion, and sedimentation of aquatic environments. Application of the Soil Water Assessment Tool (SWAT) was assessed for its ability to simulate hydrologic and water quality conditions observed in military landscapes at 5th Canadian Division Support Base (5 CDSB) Gagetown, New Brunswick. Despite some limitations, this model adequately simulated three partial years of daily watershed outflow (NSE = 0.47–0.79, R2 = 0.50–0.88) and adequately predicted suspended sediment yields during the observation periods (%d = 6–47%) for one highly disturbed sub-watershed in Gagetown. Further development of this model may help guide decisions to develop or decommission training areas, guide land management practices and prioritize select landscape mitigation efforts.
Immobilized Coriolopsis sp. laccase for continuous elimination and transformation of phenolic micropollutants
Authors: Songulashvili George , Jimenéz-Tobón Gloria A. , Jaspers Charles , Gratia Jean-Pierre , Debaste Frédéric , Penninckx Michel J.
Published: November 2014

The evaluation of continuous elimination and transformation of toxic endocrine disruptors micropollutants (MPs) (Bisphenol A, Nonylphenol [NP] and Triclosan [TCS]) using immobilized laccase of Coriolopsis sp. showed the high potential of this laccase as a bio-agent for the elimination and transformation process of selected MPs. A toxicology test using Escherichia coli has shown that toxicity completely disappeared after transformation and elimination of Bisphenol A, while in cases of NP and TCS 95% and 90% toxicity, respectively, disappeared. As compared to initial activity, immobilized laccase activity remained practically constant at the end of several runs of elimination and transformation processes of MPs. This feature is promising for the use of immobilized Coriolopsis sp. laccase in a future industrial depollution process.
Effects of Coil Design on Induction Welding of Sintered Iron Based Compacts
Authors: Çavdar Uğur , Kusoglu İhsan Murat
Published: November 2014

Sintered iron based compacts were welded by applying a high frequency induction process. The cross-sections of the compacts were square in shape so two different coil shapes, cylindrical and square, were studied with respect to the effect of magnetic flux. The effect of welding duration on the macrostructural changes and mechanical properties of the induction welded compacts were investigated for welding durations of 3, 5 and 10 minutes.
Finite Element Analysis of Calibration Coefficients for Residual Stress Measurements by the Ring Core Procedure
Authors: Xu Lianyong , Zhao Hailun , Jing Hongyang , Han Yongdian
Published: November 2014

Finite element analysis (FEA) and experiments have been conducted to analyze the calibration coefficient for measuring residual stress in the ring core method. In this publication, firstly, the calibration coefficients were determined using FEA. Then, factors which affect the calibration coefficients were investigated, such as the tensile load applied to the components, the geometric sizes of the annular grove and the location of the strain gage. The results of FEA were consistent with the experimental results. The most appropriate geometric sizes of the annular groove and location of the strain gage were obtained. This study also defines the distortion energy parameter S to calculate and modify the calibration coefficients. Hence, it is reasonable to apply FEA to calibration coefficients in the ring core method.
Finite Element Analysis of Friction Stir Welded Aluminum Alloy AA6061-T6 Joints
Authors: Serindağ Hüseyin Tarik , Kiral Binnur Goren , Kadayifçi Zeki Alper
Published: November 2014

The aim of this study was to develop a finite element model for predicting the transient temperature and stress fields during friction stir welding. For this purpose, a three-dimensional model based on the nonlinear finite element analysis (FEA) has been generated. The experimentally measured temperatures by using an infrared thermometer during experiments were compared to the results obtained by FEA. In the numerical simulations, mechanical and physical properties were considered depending on temperature. The effect of the rotational and transverse speeds on the distribution of temperature and stresses in the welded AA6061-T6 plates were examined. It was observed that the maximum temperature near the weld region increases with increasing rotational speed. The normal stresses, σx and σy also increase as the rotational speed increases. The temperature decreases as the tool transverse speed increases.
Heat Treatment Effects on the Mechanical Properties and Microstructure of 30MnB4 Steel Bolts
Authors: Kınıt Umut , Bozca Mehmet
Published: November 2014

This study targeted the effects of heat treatment on the mechanical properties of high-strength steel bolts. High-strength steel bolt samples were manufactured by sequential cutting, cold forming, heading and heat treatment. All sample bolts were M12, and the material was 30MnB4. During the heat treatment, quenching and tempering were applied to high-strength steel. Stress-strain curves were obtained for the steel bolt samples after different heat treatments. The mechanical properties of the steel bolts, such as yield strength, tensile strength, hardness and elongation, were determined for the various heat treatments. It was concluded that heat treatment is an important process that changes the microstructure of the steel bolts and their mechanical properties. By heat treatment at different temperatures it is possible to obtain high-strength steel bolts with different properties.
Aluminum Foam Structures and Compressive Properties Produced from Multiple and Differently Arranged Precursors
Authors: Asavavisithchai Seksak , Trepetch Supasiri , Sutisakomon Chonlatid
Published: November 2014

Large closed cell aluminum foam components, produced through a powder metallurgical route, normally need multiple foamable precursors. The larger the size of components, the more precursors are required. The placement of precursors in the mold prior to sintering is important for a successful foaming. The present study shows that the initial precursor arrangement has a significant effect on the final foam structure and its mechanical properties. The largest foam expansion, close to the geometry of the mold, with more uniform pore distribution was found in the foam with the arrangement of four precursors, which were placed horizontally at the bottom of the mold in two layers. This was due to the delayed foam collapse as a result of the different onsets of individual precursor expansion. The difference in heat conduction of distinct precursor positions resulted in different cellular structural characteristics which strongly affect compressive behavior of the Al foams.
The Effect of Aging Parameters and Roughness on the Wear Properties of Aluminum Alloy 6082
Authors: Cetinel Hakan , Ayvaz Mehmet
Published: November 2014

The aim of this study was to investigate the influence of aging parameters and initial roughness on the wear properties of the aluminum alloy AA 6082 (Al-Mg-Si). For this purpose, various heat treatments were carried out. Afterwards, the solutionized samples and artificially aged samples (at 185 °C for 3 and 6 h) were prepared in terms of two different average surface roughnesses via various grades of grinding. The wear behavior of the samples was investigated by a pin-on-disc wear test apparatus under four different applied loads (5, 10, 15 and 20 N) and five different sliding distances (250, 500, 750, 1000, 1250 and 1500 m). The sliding velocity was 30 cm × s−1. After the wear tests, the mass loss was measured for all samples and the worn surfaces were examined by scanning electron microscopy (SEM). The wear test results clearly show that with increasing hardness, the mass loss decreases, and the mass loss of the worn surfaces increases with increasing sliding distance, test load and initial roughness.
Behavior of Chopped Strand Mat and Woven Roving under Bending
Authors: Arifin Ahmad Mubarak Tajul , Abdullah Shahrum , Zulkifli Rozli , Wahab Dzuraidah Abdul , Rafiquzzaman Mohammad
Published: November 2014

In this study, lamination panels were fabricated using chopped strand mat (CSM) and woven roving fabric (WR) as reinforcement for two different types of specimens, type Eband type Pb, respectively. By a combination of plain materials composite lamination structures were formed, with [CSM/0/90/CSM]2sas an orientation layer for the structures. In this research study, the structural panel was produced by hand lay-up technique with a combination of unsaturated epoxy and polyester resin, separately. Therefore, with this publication, a characteristic combination of chopped strand mat/woven roving fabric, are presented. The experimental work for both types of specimens were performed by bending until the structure fails. The characteristics of different materials, i. e. the chemicals used and the composite lamination structure, were studied, because there are different types of damages in the structure of composite materials, such as delamination, matrix cracking, fiber-matrix damage and fiber pull-out. Furthermore, it can affect the behavior of composite materials in the whole structure. As a result, this process contributes to failure prevention, as the capabilities of the structures are known, before it can be used for any part, component or area. It was also shown that different configuration lamination layers influence the strength properties of the composite materials.
Experimental and Numerical Analysis of Foam-Filled Aluminum Conical Tubes Subjected to Oblique Impact Loading
Authors: Mat Fauziah , Ismail Khairul Azwan , Yaacob Sazali , Ahmad Zaini
Published: November 2014

This study aims to investigate the response of AA6061-T6 conical tubes under oblique impact loading, for variations in filler density and tube material by using experimentally validated model. Good correlations between the numerical and experimental results were observed. The initial peak force and dynamic force increase from AA6061-T6 to carbon steel tubes and further increase with increasing filler density, leading to increased energy absorption capacity. Conversely, the initial peak force and dynamic force of empty and foam-filled AA6061-T6 conical tubes decrease with the introduction of oblique loading as the load angle increases from 0° to 20°, leading to reduced energy absorption capacity. Carbon steel is relatively more advantageous compared with AA6061-T6 in terms of energy absorption, whereas AA6061-T6 is comparable with carbon steel because of its lower initial peak force.
Effects of Cutting Parameters and Point Angle on Thrust Force and Delamination in Drilling of CFRP
Authors: Yardimeden Ahmet , Kilickap Erol , Celik Yahya Hisman
Published: November 2014

Parts made of composite materials are generally produced by near-net-shape technology. However, additional machining operations such as drilling are often required to facilitate components assembling. Drilling of composite materials is also a common process in the assembly of aerospace and automotive composite structures. During drilling, unlike the conventional materials, a few damage forms may take place. Among these damage forms, the delamination is the most important one. Therefore, the experimental studies carried out on drilling of CFRP composite materials for determining optimum processing parameters are of great importance. In this particular study, delamination in CFRP composites caused by drilling was investigated. The composite material was drilled under various spindle speeds, feed rates and drill point angles. The results showed that delamination and thrust forces were affected by cutting parameters. It was demonstrated that feed rate and drill point angle make the largest contribution to the overall performance.
Formulation and evaluation of dexamethasone loaded stearic acid nanoparticles by hot homogenization method
Authors: Parvin Shumaia , Rafshanjani Md. Abu Shuaib , Kader Md. Abdul
Published: November 2014

Dexamethasone is a type of steroid medication having anti-inflammatory and immunosuppressant effects. One of the major problems with this drug is its low solubility in water which results into poor bioavailability after oral administration. So the objective of the present work is to improve the solubility and dissolution rate of dexamethasone using its solid lipid nano particles (SLNPs) with stearic acid as solid lipid, lutrol F-68 as surfactant and tween-80 as stabilizer. SLNPs are prepared by hot homogenization method at different ratio of drug, lipid, surfactant and stabilizer and designated as DNP1 to DNP6. In vitro dissolution study was performed using the USP type II apparatus (paddle method) at 50 rpm to a temperature of 37°±0.5°C in distilled water containing 0.75% w/v SLS (sodium lauryl sulfate). The absorbance of sample was measured spectrophotometrically at ?max 239nm on a UV-Visible spectrophotometer. Release pattern of drug was found to follow zero order, first order and Korsmeyer-Peppas equations. Improvement of dissolution was observed in all the solid lipid nano particles as compared to pure drug. Pure drug showed only 27.25% release in 50 min whereas the dexamethasone SLNPs showed faster (66.19%) in vitro drug release. Hence, this finding indicates that dexamethasone SLNPs prepared by hot homogenization method can be used to enhance the dissolution rate and to show novel application to this drug delivery system.DOI: http://dx.doi.org/10.3329/icpj.v3i12.20829 International Current Pharmaceutical Journal, November 2014, 3(12): 331-335
Analysis on Effectiveness of SO2 Emission Reduction in Shanxi, China by Satellite Remote Sensing
Authors: Song Huaxiang , Yang Minhua
Published: November 2014

The SO2 emissions from coal-fired power plants in China have been regulated since 2005 by a mandatory installation of flue gas desulfurization (FGD) devices. In order to verify the effectiveness of FGD systems applied in power plants, Shanxi (a province well-known for the largest coal reserves in China) was selected, and the characteristic and evolution of SO2 densities over 22 regions with large coal-fired power plants during 2005–2012 were investigated by using the satellite remote sensing data from the Ozone Monitoring Instrument (OMI). A unit-based inventory was also employed to study the trend of SO2 emissions from coal-fired power plants in Shanxi. The results show that the operation of FGD systems was successful in reducing SO2 emissions from power plants during 2005–2010: the mean SO2 densities satellite-observed over those regions with power plants operated before 2005 showed a notable decrease of approximate 0.4 DU; the mean SO2 densities over other regions with power plants newly built behind 2006 did not show a statistical increasing trend overall; the mean SO2 density over the whole Shanxi also showed a moderate decline from 2008 to 2010. However, the polluted conditions over Shanxi during 2011–2012 rebounded and the declining trend in mean SO2 density over the whole Shanxi disappeared again. In comparison of unit-based emission inventory, the emissions calculated show a similar trend with SO2 densities satellite-observed during 2005–2010 and still maintain at a lower volume during 2011–2012. By investigating the developments of other emission sources in Shanxi during 2005–2012, it is considered that the rapid expansion of industries with high coal-consumption has played an important role for the increment rise of SO2 emissions. Lack of an independent air quality monitoring network and the purposeful reduced operation rate of FGD systems occurring in some coal-fired power plants have reduced the effectiveness of SO2 emission reduction policy applied in Shanxi. In view that the SO2 pollution in Shanxi has not been well ameliorated, more reasonable and mandatory policies, such as a national-wide independent monitoring network and installation of FGD systems in other large emission sources, should be pushed out in the near future.
Knowledge, Attitudes and Practices Regarding Cervical Cancer and Screening among Haitian Health Care Workers
Authors: Zahedi Leilah , Sizemore Emma , Malcolm Stuart , Grossniklaus Emily , Nwosu Oguchi
Published: November 2014

It is estimated that Haiti has the highest incidence of cervical cancer in the Western Hemisphere. There are currently no sustainable and affordable cervical cancer screening programs in Haiti. The current status of screening services and knowledge of health care professionals was assessed through a Knowledge, Attitudes, and Practices survey on cervical cancer screening and prevention. It was distributed to Project Medishare for Haiti health care workers (n = 27) in the Central Plateau. The majority (22/27) of participants stated pre-cancerous cells could be detected through screening, however, only four had ever performed a pap smear. All of the participants felt a screening program should be started in their area. Our data establishes that knowledge is fairly lacking among healthcare workers and there is an opportunity to train them in simple, cost effective “screen-and-treat” programs that could have a great impact on the overall health of the population.
Micromachining of AlN and Al2O3 Using Fiber Laser
Authors: Preusch Florian , Adelmann Benedikt , Hellmann Ralf
Published: November 2014

We report on high precision high speed micromachining of Al2O3 and AlN using pulsed near infrared fiber laser. Ablation thresholds are determined to be 30 J/cm2 for alumina and 18 J/cm2 for aluminum nitride. The factors influencing the efficiency and quality of 3D micromachining, namely the surface roughness, the material removal rate and the ablation depth accuracy are determined as a function of laser repetition rate and pulse overlap. Using a fluence of 64 J/cm², we achieve a material removal rate of up to 94 mm³/h in Al2O3 and 135 mm³/h in AlN for high pulse overlaps (89% and 84%). A minimum roughness of 1.5 μm for alumina and 1.65 μm for aluminum nitride can be accomplished for medium pulse overlaps (42% to 56%). In addition, ablation depth deviation of the micromachining process of smaller than 8% for alumina and 2% for aluminum nitride are achieved. Based on these results, by structuring exemplarily 3D structures we demonstrate the potential of high quality and efficient 3D micromachining using pulsed fiber laser.
Curcumin Reverse Methicillin Resistance in Staphylococcus aureus
Authors: Mun Su-Hyun , Kim Sung-Bae , Kong Ryong , Choi Jang-Gi , Kim Youn-Chul , Shin Dong-Won , Kang Ok-Hwa , Kwon Dong-Yeul
Published: November 2014

Curcumin, a natural polyphenolic flavonoid extracted from the rhizome of Curcuma longa L., was shown to possess superior potency to resensitize methicillin-resistant Staphylococcus aureus (MRSA) to antibiotics. Previous studies have shown the synergistic activity of curcumin with β-lactam and quinolone antibiotics. Further, to understand the anti-MRSA mechanism of curcumin, we investigated the potentiated effect of curcumin by its interaction in diverse conditions. The mechanism of anti-MRSA action of curcumin was analyzed by the viability assay in the presence of detergents, ATPase inhibitors and peptidoglycan (PGN) from S. aureus, and the PBP2a protein level was analyzed by western blotting. The morphological changes in the curcumin-treated MRSA strains were investigated by transmission electron microscopy (TEM). We analyzed increased susceptibility to MRSA isolates in the presence of curcumin. The optical densities at 600 nm (OD600) of the suspensions treated with the combinations of curcumin with triton X-100 and Tris were reduced to 63% and 59%, respectively, compared to curcumin without treatment. N,N'-dicyclohexylcarbodiimide (DCCD) and sodium azide (NaN3) were reduced to 94% and 55%, respectively. When peptidoglycan (PGN) from S. aureus was combined with curcumin, PGN (0–125 μg/mL) gradually blocked the antibacterial activity of curcumin (125 μg/mL); however, at a concentration of 125 µg/mL PGN, it did not completely block curcumin. Curcumin has a significant effect on the protein level of PBP2a. The TEM images of MRSA showed damage of the cell wall, disruption of the cytoplasmic contents, broken cell membrane and cell lysis after the treatment of curcumin. These data indicate a remarkable antibacterial effect of curcumin, with membrane permeability enhancers and ATPase inhibitors, and curcumin did not directly bind to PGN on the cell wall. Further, the antimicrobial action of curcumin involved in the PBP2a-mediated resistance mechanism was investigated.
In Vitro Antioxidant and Antiproliferative Activities of Methanolic Plant Part Extracts of Theobroma cacao
Authors: Baharum Zainal , Akim Abdah , Taufiq-Yap Yun , Hamid Roslida , Kasran Rosmin
Published: November 2014

The aims of this study were to determine the antioxidant and antiproliferative activity of the following Theobroma cacao plant part methanolic extracts: leaf, bark, husk, fermented and unfermented shell, pith, root, and cherelle. Antioxidant activity was determined using 2,2-diphenyl-2-picrylhydrazyl (DPPH), thiobarbituric acid-reactive substances (TBARS), and Folin-Ciocalteu assays; the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium (MTT) assay was used to determine antiproliferative activity. The root extract had the highest antioxidant activity; its median effective dose (EC50) was 358.3 ± 7.0 µg/mL and total phenolic content was 22.0 ± 1.1 g GAE/100 g extract as compared to the other methanolic plant part extracts. Only the cherelle extract demonstrated 10.4% ± 1.1% inhibition activity in the lipid peroxidation assay. The MTT assay revealed that the leaf extract had the highest antiproliferative activity against MCF-7 cells [median inhibitory concentration (IC50) = 41.4 ± 3.3 µg/mL]. Given the overall high IC50 for the normal liver cell line WRL-68, this study indicates that T. cacao methanolic extracts have a cytotoxic effect in cancer cells, but not in normal cells. Planned future investigations will involve the purification, identification, determination of the mechanisms of action, and molecular assay of T. cacao plant extracts.
Exercise-Trained Men and Women: Role of Exercise and Diet on Appetite and Energy Intake
Authors: Howe Stephanie , Hand Taryn , Manore Melinda
Published: November 2014

The regulation of appetite and energy intake is influenced by numerous hormonal and neural signals, including feedback from changes in diet and exercise. Exercise can suppress subjective appetite ratings, subsequent energy intake, and alter appetite-regulating hormones, including ghrelin, peptide YY, and glucagon-like peptide 1(GLP-1) for a period of time post-exercise. Discrepancies in the degree of appetite suppression with exercise may be dependent on subject characteristics (e.g., body fatness, fitness level, age or sex) and exercise duration, intensity, type and mode. Following an acute bout of exercise, exercise-trained males experience appetite suppression, while data in exercise-trained women are limited and equivocal. Diet can also impact appetite, with low-energy dense diets eliciting a greater sense of fullness at a lower energy intake. To date, little research has examined the combined interaction of exercise and diet on appetite and energy intake. This review focuses on exercise-trained men and women and examines the impact of exercise on hormonal regulation of appetite, post-exercise energy intake, and subjective and objective measurements of appetite. The impact that low-energy dense diets have on appetite and energy intake are also addressed. Finally, the combined effects of high-intensity exercise and low-energy dense diets are examined. This research is in exercise-trained women who are often concerned with weight and body image issues and consume low-energy dense foods to keep energy intakes low. Unfortunately, these low-energy intakes can have negative health consequences when combined with high-levels of exercise. More research is needed examining the combined effect of diet and exercise on appetite regulation in fit, exercise-trained individuals.