bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Alkaline Agents on the Transport of Polysaccharides in a Carbonate Matrix
Authors: Servin Jesus M. , Ellis Erika S. , Shateeb Hussain , Schmidt Howard K.
Published: October 2017

Nanoparticles have potential for multiple applications in the oil and gas industry, ranging from EOR operations to improved drilling fluids and cements, as well as reservoir monitoring and characterization. The two biggest challenges to overcome for nanoparticles in the reservoir are stability at reservoir conditions and retention. Understanding the mechanisms controlling transport and retention in porous media is essential to develop nanoparticles able to successfully traverse the reservoir. A commonly used strategy to stabilize nanoparticles and reduce retention is to functionalize their surface or to coat them with polymers. Although the coatings help stabilize the nanoparticles, retention is still a major challenge preventing field wide applications. Previous studies have shown that increasing the pH of injected water reduces the amount of surfactants (chemically similar to polysaccharides) adsorbed to the rock. This paper presents the results of a study that investigates the possibility of improving the transport properties of a polysaccharide coating (dextran) through a carbonate matrix by altering the pH using an alkaline passivation agent (sodium metaborate). The amount of retention was quantified by fluorescently tagging the dextran and measuring the intensity of fluorescence of the effluents using a portable spectrometer. The intensity of fluorescence of the effluents should be proportional to the amount of dextran being recovered. The results show that the alkali passivation agent reduces retention of the coating by ~16%.
Standardizing Reservoir Management Best Practices in KOC
Authors: Capello Maria A. , Al-Bahar Mohammad , Sizer Jim , Kansao Rami , Al-Mutairi Fahad , Al-Shammari Hanaa S.
Published: October 2017

Kuwait's oil and gas reservoirs shape one of the largest reservoir portfolios worldwide, meriting savvy and forward-looking reservoir management practices and workflows to maintain the country as a reliable supplier for many decades to come. Reservoir management can be defined as a body of principles, processes, and practices that collectively governs the way a field is managed. It is focused on the subsurface, but not exclusively. Reservoir management is a stewardship process that significantly impacts production performance, bookable reserves, estimated ultimate recovery (EUR), and capital expenditures (CapEx). Kuwait Oil Company (KOC) has set out to optimize and standardize its reservoir management practices at a corporate level (Capello et al. 2016).

This journey is still in progress, and has several strategic objectives: a) standardize reservoir management practices across KOC assets; b) ensure the optimization of recovery factors and life of fields strategies for each reservoir enabling the simultaneous production of nearby, connected or stacked producing intervals, with different maturity levels; c) extend production plateaus in time for each KOC asset; and d) ensure the active participation in reservoir management activities of a skilled workforce.

The ultimate aim is to apply industry best practices in managing the oil and gas fields in Kuwait. The initiative is called Reservoir Management Best Practices (RMBP), and comprises a two-fold effort:

A Steering Committee composed of 10 managers is charged with the implementation of reservoir management best practices policies and guidelines across all KOC assets. It was essential that management endorsed the initiatives and assured buy-in from other managers, team leaders and seniors in all assets and support organizations within KOC. Six Process Implementation Projects (PIP) were tackled with key objectives and elements of RM. It is envisioned that these PIPs will impact and uplift the way all assets work, so technical staff participation and buy-in was paramount for a successful implementation.

The approach taken by KOC merges technical emphasis and international best-in-class practices with change management and communication strategies to align efforts. Most importantly, this solidifies and builds commitment and a shared motivation to achieve common goals.

This paper summarizes the main accomplishments of KOC's RMBP to date, which span from workflows and governance in data management, to automation of drilling proposals and analog databases for reservoirs. KOC estimates these new processes will reduce operating costs and increase capital efficiency, which in turn will increase profitability by up to 15%.
New Methodology to Evaluate the Performance of Chemical Sealant Loss Circulation Materials
Authors: Abdulrazzaq Waseem , AlBuraikan Reem , Savari Sharath , Whitfill Donald L.
Published: October 2017

A new laboratory work procedure has been developed to evaluate and test the performance and effectiveness of chemical-sealant-based loss circulation materials (CS-LCMs), which are often used in cases of severe-to-total losses. These unconventional testing methods should be useful tools to evaluate the integrity of loss circulation material (LCM) products under downhole conditions in terms of differential pressure buildup and how quickly such LCMs can arrest lost circulation.

Evaluation and testing of LCMs in the laboratory before field application are crucial. Conventionally, the plugging capacity of particulate LCMs is tested against various-sized slotted discs using a permeability plugging apparatus (PPA), and integrity is tested in terms of sealing capacity and fluid loss value. Testing the performance of CS-LCMs required another means that included plugging extra-large vugs and building a significant differential pressure that could sustain the drilling fluid column. Pumpability of CS-LCMs and mechanical strength performance over time were evaluated using a high-pressure/high-temperature (HP/HT) consistometer, ultrasonic cement analyzer (UCA), and modified PPA following this fit-for-purpose procedure.

Extensive laboratory testing revealed that the new testing method was highly compatible with almost all types of chemical-based LCMs, including resin, gunk squeeze, and thixotropic slurries. The effectiveness and performance of several commercially available CS-LCMs were measured using different vug sizes (i.e., up to tens of millimeters). Thickening time of LCMs were observed pumpable [i.e., <70 Bearden units of consistency (Bc)], even after hours of conditioning at bottomhole circulating temperatures (BHCTs). As per API routine practice, tested slurry is deemed unpumpable if Bc exceeds 70. However, the thickening time of gunk squeeze LCMs were observed to be significantly high in a short interval of time once aqueous and nonaqueous streams mixed together. Gunk-based LCMs build high differential pressures and compressive strength over the same periods of curing time at bottomhole static temperature (BHST) and pressure compared to thixotropic-based LCMs.

Appropriate laboratory testing and evaluation of chemical-based LCMs under downhole conditions are highly recommended before field trail/application. This new testing/evaluation method should help minimize operational risk and nonproductive time (NPT) at the rig site.
Application of Real-Time Data and Integrated Models in an Automated Workflow for Production Surveillance and Analysis in Burgan Oil Field
Authors: Al-Shammari B.. , Rane N. M. , Desai S F , Sabea Al , Hamad Salem , Pandey M.. , Shankhdhar S.. , Chacko R.. , Ledesma S. F..
Published: October 2017

The GC-01 KwIDF system has been deployed in the East Kuwait area of Burgan oil field and includes real time production surveillance instrumentation for wells and production facility. The raw data from the wells and facility is integrated with well and network models in an automated workflow process for surveillance and analysis of the GC-01 production.

The Burgan oil field integrated digital field (KwIDF) automation system utilizes wellhead pressure and water-cut measurements for automated calibration of well and surface network models. The KwIDF system workflow utilizes calibrated well models and real time data to identify changes in GC-01 daily production and reconciles it with the contributing wells. The workflow identifies wells with production changes and associates them with key well and facility parameters for instant diagnosis and analysis of daily production issues.

This paper describes the application of real time data and integrated models in an automated workflow for quick identification and analysis of daily field production.

Examples describe how the workflow has been used in quick analysis and decision making to optimize daily production and achieve sustainable targets in one of the production facilities of the Greater Burgan Field in Kuwait.
Application of Artificial Intelligence Techniques in Estimating Oil Recovery Factor for Water Derive Sandy Reservoirs
Authors: Ahmed Ahmed Abdulhamid , Elkatatny Salaheldin , Abdulraheem Abdulazeez , Mahmoud Mohamed
Published: October 2017

Oil and gas operating companies are always concerned with evaluating the reserve of their assets. Evaluation process of hydrocarbon reserves requires a full understanding and knowledge of technical and non-technical aspects regarding the nature of reservoir, available technology and economic conditions as well as others. Recovery factor (RF) is the most important parameter in evaluating the reserve of new fields.

Several techniques are currently available for estimating oil recovery factor, the accuracy of those techniques are highly affected by data availability which is mainly related to the field age. Some of the techniques are highly accurate but they require lots of production data, hence, their applicability early in the reservoir life is restricted. Others could be applied earlier, but on the other hand, they have very low accuracy.

In this paper ten parameters (original oil in place, asset area, net pay, initial reservoir pressure, porosity, permeability, Lorenz coefficient, API gravity, initial water saturation and oil viscosity), which are usually available early in the life of the reservoir, are used to estimate the oil recovery factor through application of four Artificial Intelligence (AI) techniques namely: artificial neuron networks (ANNs), Radial Basis Neuron Network (RNN), ANFIS-2 (Adaptive Neuro Fuzzy Inference System, Subtractive Clustering), and SVM (Support Vector Machines). Data from 130 sandstone reservoirs were used to learn the AI models, and then an empirical correlation was developed based on the ANN model. The suggested AI models and the developed ANN-based correlation were then tested in other 38 sandstone reservoirs.

The results obtained showed that ANN-based correlation successfully predicted the recovery factor based on early time data only with absolute average percentage error (AAPE) of 7.92%, coefficient of determination (R2) of 0.9417, root mean square error (RMSE) and maximum absolute percent error (MAE) of 3.74 and 24.07%, respectively. ANN-based empirical correlation over-performed RNN, ANFIS-2, and SVM models in term of AAPE, MAE, and RMSE for testing set. Comparison of the recovery factor predicted by the developed equation with three available correlations showed that the developed equation predictability is about 5 times better that the most accurate correlation (of the currently available ones) in term of AAPE for predicted RF of the tested 38 reservoirs.
Estimation of Geomechanical Failure Parameters from Well Logs Using Artificial Intelligence Techniques
Authors: Alloush R. M. , Elkatatny S. M. , Mahmoud M. A. , Moussa T. M. , Ali A. Z. , Abdulraheem A..
Published: October 2017

Geomechanical failure parameters are best estimated from core samples, which are not always available. To address this, numerous relationships have been proposed that relate rock strength to parameters measurable with geophysical well logs, but they tend to have limited accuracy or low range of applicability. This paper aims at overcoming the limitations of the existing techniques by using different artificial intelligence techniques (AI).

The data used in this study are usually available from the commonly conducted well log surveys (neutron porosity, gamma ray and bulk density) as well as the sonic log. Data sets from 10 wells in carbonate formations and 30 core samples were used to build a simple, yet powerful, model that can predict the rock failure parameters from well logs. The derived model is working because it considers many factors that affect both the rock strength and elastic moduli.

Three artificial intelligence techniques; Artificial Neural Networks (ANNs), Adaptive Neuro-Fuzzy Inference System (ANFIS), and Support Vector Machines (SVM) were used to predict three geomechanical failure parameters, namely: the angle of internal friction (friction angle or FANG), unconfined compressive strength (UCS) and tensile strength (TSTR). For each parameter, the three AI techniques were implemented to train AI models and then unseen data was used to validate the models.

From the three tested AI techniques, ANN model gave the best results and out-performed the other models obtained using ANFIS and SVM for the FANG prediction, with correlation coefficient of 0.98 and AAPE around 5.8%. The ANN model was programmed in a (white box) manner, which allowed the successful extraction of the weights and biases from the network to be easily used. For TSTR and UCS prediction, ANFIS models performed better than ANN and SVM. The two ANFIS models had correlation coefficients of 0.99 and Average Absolute Percentage Errors (AAPE) of 4.9% and 3.7% respectively.
Depositional History of the Eocene Dammam Formation in Kuwait
Authors: Tanoli Saifullah Khan , Al-Bloushi Abrar Jumah
Published: October 2017

The sedimentation of Eocene age Dammam Formation started as a result of sea transgression above the evaporitic sequence of the underlying Rus Formation. The transgressing sea water filled the low land in coastal areas where muddy limestone was deposited and overlying brown dolomitized limestone was deposited in shallow peritdal environments. Due to continued transgression, a stratified intrashelf basin was developed where semi-anoxic to anoxic conditions prevailed and which resulted into the deposition of dark grey to black mudstone facies. Maximum flooding surface Pg20 of the Arabian Plate is correlated to lie within this zone. As the transgression subsided, shallow open marine conditions were developed where foraminifera nummulites thrived. These nummulites made shoals and banks behind which due to low energy protected setting in place deposition of calcareous sponge, Lockhartia, and nummulites occurred. Upwards, the nummulites gradual decrease and environments further shallow up resulting into the deposition of parallel laminated bioclastic limestone in inner ramp to intertidal environments. A second transgression took place in the middle of the Dammam Formation due to which a large lagoon type set up was developed. The chalky micritic facies was deposited in this quite water lagoonal setting with intertidal influence in its upper part. The proceeding yellowish brown dolomite facies has common fenestrae structures and rubbled zones along with chert nodules and stringers. This facies is very porous and was deposited in intertidal to supratidal environments. The uppermost dolostone has common chert stringers and bands and common rubbled zones developed by collapsed dissolution cavities likely related to exposure surfaces.

The Dammam Formation displays two transgressive-regressive depositional sequences. The formation has excellent reservoir characteristics in the form of overall high porosity which exceeds 40% in some zones. Hydrocarbon shows in the form of bitumen remains are observed within the formation.
The Value of Integrated Borehole Image Analysis to Refine Geological Models: An Example from the Greater Burgan Field, Kuwait.
Authors: Kostic B.. , Foote N.. , Al-Enezi B.. , Filak J. M. , Al-Mahmeed F..
Published: October 2017

Resistivity image logs are high-resolution tools that can help to unravel the depositional and structural organisation in a wellbore. They provide a particularly powerful dataset when calibrated against core, maximising their benefit for reservoir characterisation. This paper shows examples how very detailed image assessment from selected wells in the Greater Burgan Field has helped to constrain the stratigraphic model and depositional interpretations of the Cretaceous Burgan and Wara reservoirs.

A multidisciplinary study of 123 cored wells, integrating core sedimentology, petrography, bioand chemostratigraphy, wireline well and resistivity image logs, has delivered a robust stratigraphic and depositional framework for one of the most important reservoirs in the world's largest siliciclastic oil field. A descriptive image facies scheme that has been calibrated against core and conventional well logs captures the lithological variation, sedimentary features and surfaces of the reservoir, providing a detailed proxy for the sedimentological evaluation of uncored intervals and wells.

The sand-rich lower Burgan (4S) comprises fine to very coarse-grained fluvial channel sandbodies that are locally separated by laterally restricted mudrock baffles. Image and core analyses suggest that the majority of the sandstones are high-angle cross-stratified and form stacked barforms within amalgamated channel sandbodies. Their consistent orientation towards the NE-E supports a low-sinuosity (braided) fluvial system resulting in a relatively simple, sheet-like depositional architecture across the field. Although slightly finer grained, the cored middle Burgan channel sandbodies (3SM) are similar to those in the lower Burgan. However, palaeoflow data from the imaged wells show a higher directional spread in the order of c.60-90° with a dominantly N to E orientation of the sandy barforms. Careful analysis of the orientation of the bounding surfaces between the sandstone packages indicates nearly equal proportions of obliquely and roughly parallel dip orientations in some wells. This suggests the formation of at least some lateral (point) bars and possibly the presence of higher sinuosity channels implying that sandbody architecture and fluid flow pathways could be more complex in the middle Burgan relative to the lower Burgan.

The examples from the Burgan and Wara Formations highlight the value of integrated image analysis for reservoir characterisation by delivering a consistent descriptive framework, embedding different datasets.
The Impact of Condensate Blockage on Gas Well Deliverability - Part 1
Authors: Khazam M. M. , Abu Grin Z. Y. , Elhajjaji R. R. , Sherik A. A.
Published: October 2017

Predicting and assuring well deliverability is often an important concern during the development of gas-condensate reservoirs, especially offshore fields. In addition, production of gas is usually bound with long-term contracts where it is necessary to assure well deliverability for a long period. Undesirably, well deliverability in gas-condensate reservoirs can be impaired by the formation of a condensate blockage once the bottomhole flowing pressure drops below the dewpoint pressure. In this case, the relative permeability of the gas phase can be significantly reduced due to this condensate accumulation around the wellbore. Therefore, quantifying this negative effect is essentially required to obtain reliable predictions of well deliverability in gas-condensate reservoirs. The evaluation of condensate blockage phenomenon requires an appropriate understanding of flow characteristics of both gas and condensate liquid through reservoir rocks.

In this study, the impact of condensate blockage on gas well deliverability was investigated by examining a number of flow parameters such as absolute permeability (K), critical condensate saturation (Scc), relative permeability shape and end-points (krgmax, kromax). A single well radial and cartesian models were both used in different simulators (modified black-oil and compositional).

The outcomes of this study showed that the condensate blockage can have a severe negative impact at low permeability reservoirs (K≈5md), while the impact can be small at moderate permeability (k≈50md) and diminishable at high permeability reservoirs (k≈200md). This negative impact can double at high critical condensate saturation (Scc>30%). It was found out that the relative permeability curves applied in the model define the magnitude of the blockage, especially in low permeability reservoirs, whereas relative permeability end-points (krgmax and kromax) affect mainly the overall gas recovery. Previous lab measurements showed that gas-condensate relative permeabilities are sensitive to flow velocity only in low permeability reservoirs. This effect was modeled using a compositional model through the capillary number. Velocity-dependent relative permeability model applied in this case showed that the plateau period can be improved by a factor of two in low permeability. On the other hand, no positive effect was observed at moderate and high permeability since the blockage effect was already small or dimensionless.

Finally, the benefit of methanol injection was investigated for improving well deliverability at low permeability reservoirs. Based on this analysis, methanol treatment can improve gas well deliverability and substantially prolong the plateau period by a factor of 2-3.
Unique Carbonate Matrix Stimulation Software; Customized for KOC
Authors: AL-Othman Mohammad , Buhamad Ali , AL-Mohammad Homoud
Published: October 2017

Acid stimulation is the means of improving the well productivity in hydrocarbon production wells. Carbonate formations are tolerance to wrong acid stimulation practices, and Kuwait reservoirs are not exception. Matrix stimulation for carbonate reservoirs is one of the most frequent operation in KOC. It is always associated with operational and technical challenges in order to select and design the proper stimulation method. The main challenges are selecting the acid type, concentration, dosage and diversion method, besides selecting the most suitable stimulation technique for each individual well and formation. It was important to create an adequate procedure to unify a solution for the faced challenges. Programming a software that provide a full acid stimulation program has been done by KOC Well Surveillance Group "First of its kind in KOC". The software is built based on KOC data base for all carbonate wells. These data went through a sequence of analysis and been grouped based on; reservoir's rock properties, fluid properties, reservoir's pressure/temperature, fluid compatibility, and formation lithology. By using the Software, the user will be able to overcome the mentioned challenges. In addition, the software is able to define the corresponding treatment radius (rs), diverter type (chemical or mechanical diversion, polymer or non-polymer based fluid), pre and post flush dosage and type, and prediction of liquid gain after the well stimulation.

As a result, the variation in stimulation designs based on different level of experience and knowledge will be eliminated. Thus, the chemical dosage will be optimized from technical and operational prospective, which will reflect on the job expenses. The software is divided to five windows: two Coiled Tubing windows and two Bullheading windows (Mechanical Diversion and Chemical Diversion), and Matrix Volume Calculator window; which helps to calculate the required treatment dosage in order to cover the desired treated radius, given the casing OD and reservoir porosity.
Design & Implementation of Renewable Energy Dashboard
Authors: Kaouri Mostafa , Al-Herz Ali
Published: October 2017

To compliment the vision of His Highness Sheikh Sabah AL-Ahmad AL-Sabah to cover 15% of Kuwait's peak load with renewable energy by 2030, the Kuwait Petroleum Corporation (KPC) Strategic Directions 2030 encouraged the perusal of alternative and renewable energy sources and encourage conservation efforts. KPC established the Solar Energy Technology Utilization Team (SETUT). The objective of the team was to identify improvement opportunities relevant to solar energy technologies within Kuwait's oil sector, and to enable KPC and its subsidiaries (K-Companies) to play a more active role in energy saving by developing an effective action plan for utilizing solar energy technologies in K-Companies' facilities.

Our initiative in Kuwait Oil Company (KOC) is to support the SETUT and K-Companies in their role and responsibilities to review the energy consumption and the recovered solar energy production from renewable energy projects, and to track the progress of their projects to be proactive on making decisions to achieve 15% of the total energy needs from renewable energy sources by 2030.

This paper explores the contents of design and implementation of a dashboard initiative to support on reporting the renewable energy information such as energy consumptions vs. solar energy productions, and to track related projects progress through a milestone view. Now, Stakeholders of KPC can see all the actual & planned energy consumption and production, and can track solar energy projects progress of its own and its subsidiaries, where each stakeholder of a subsidiary can see only their own one. The dashboard is not limited to only solar energy projects, however, it can be fed with other projects data such as Green Building that has good impact on the environment, and it's ready to include any organization in Kuwait who contributes in renewable energy production to cover 15% of Kuwait peak load by 2030.
Adsorption Role in Shale Gas Recovery and the Feasibility of CO2 in Shale Enhanced Gas Recovery: A Study on Shale Gas from Saudi Arabia
Authors: Eliebid Mohammed , Mahmoud Mohamed , Elkatatny Salaheldin , Abouelresh Mohamed , Shawabkeh Reyad
Published: October 2017

Adsorption of CH4, CO2 and 10%CO2/CH4 on mature Qusaiba shale (1.81% TOC) is studied at 50, 100 and 150°C and 45 bars maximum pressure. Adsorption of CH4 was the lowest at all temperatures. As CO2 percentage increased, adsorption uptake increases concluding that CO2 is highly competitive and can be used to desorb CH4 and enhance gas recovery. Maximum adsorption uptakes were observed at 100°C because of the thermal decomposition of organic matter which opens more adsorption sites. Adsorption isotherms including Langmuir, Freundlich and BET are fitted to adsorption data. Langmuir isotherm showed the poorest fit with high errors and lowest coefficient of determination (R2). Nevertheless, Freundlich isotherm fitted the adsorption data perfectly with lowest errors and highest R2 reaching 0.999. Furthermore, adsorption thermodynamics parameters have also been determined. Heat of adsorption (ΔHads) negative values showed that adsorption is exothermic physical adsorption. Negative ΔGads showed that adsorption of CO2 is more spontaneous than CH4 with strong affinity at high temperatures. This work confirm that CO2 is viable candidate to shale gas enhanced gas recovery and Qusaiba shale can store huge amounts of CO2 especially at high temperatures.
Ploidy and Genome Size in Lilac Species, Cultivars, and Interploid Hybrids
Authors: Lattier Jason D. , Contreras Ryan N.
Published: October 2017

Genome size variation can be used to investigate biodiversity, genome evolution, and taxonomic relationships among related taxa. Plant breeders use genome size variation to identify parents useful for breeding sterile or improved ornamentals. Lilacs (Syringa) are deciduous trees and shrubs valued for their fragrant spring and summer flowers. The genus is divided into six series: Syringa (Vulgares), Pinnatifoliae, Ligustrae, Ligustrina, Pubescentes, and Villosae. Reports conflict on genome evolution, base chromosome number, and polyploidy in lilac. The purpose of this study was to investigate genome size and ploidy variation across a diverse collection. Flow cytometry was used to estimate monoploid (1Cx) and holoploid (2C) genome sizes in series, species, cultivars, and seedlings from parents with three ploidy combinations: 2x x 2x, 2x x 3x, and 3x x 2x. Pollen diameter was measured to investigate the frequency of unreduced gametes in diploid and triploid Syringa vulgaris cultivars. Three triploids of S. vulgaris were observed: ‘Aucubaefolia’, ‘Agincourt Beauty’, and ‘President Grévy’. Across taxa, significant variations in 1Cx genome size were discovered. The smallest and largest values were found in the interspecific hybrids S. ×laciniata (1.32 ± 0.04 pg) and S. ×hyacinthiflora ‘Old Glory’ (1.78 ± 0.05), both of which are in series Syringa. Series Syringa (1.68 ± 0.02 pg) had a significantly larger 1Cx genome size than the other series. No significant differences were found within series Pubescentes (1.47 ± 0.01 pg), Villosae (1.55 ± 0.02 pg), Ligustrina (1.49 ± 0.05 pg), and Pinnatifoliae (1.52 ± 0.02 pg). For S. vulgaris crosses, no significant variation in 2C genome size was discovered in 2x x 2x crosses. Interploid crosses between ‘Blue Skies’ (2x) and ‘President Grévy’ (3x) produced an aneuploid population with variable 2C genome sizes ranging from 3.41 ± 0.03 to 4.35 ± 0.03 pg. Only one viable seedling was recovered from a cross combination between ‘President Grévy’ (3x) and ‘Sensation’ (2x). This seedling had a larger 2C genome size (5.65 ± 0.02 pg) than either parent and the largest 2C genome size currently reported in lilac. ‘Sensation’ produced 8.5% unreduced pollen, which we inferred was responsible for the increased genome size. No unreduced pollen was discovered in the other diploids examined. Increased ploidy may provide a mechanism for recovering progeny from incompatible taxa in lilac breeding.
Effects of Nitrogen and Plant Density on Competition between Two Maize Hybrids Released in Different Eras
Authors: Zhai Lichao , Xie Ruizhi , Li Shaokun , Zhang Zhengbin
Published: October 2017

Core Ideas

Nitrogen application rate and plant density affect competition between maize hybrids.

Competitive outcomes are invariant under different N levels and plant densities.

Nitrogen deficiency increased the competitive advantage of the superior competitor.

Higher plant density reduced the competitive advantage of the superior competitor.

Competition is a common phenomenon in plant communities, but it remains unclear whether it is influenced by soil productivity. To investigate whether N fertilization and plant density affect competition between maize (Zea mays L.) hybrids, field experiments were conducted during the 2013 and 2014 growing seasons using a de Wit replacement series design. Two maize hybrids, YD13 and ZD909, which were released in different eras were tested. In each replacement series, dry matter accumulation (DMA), grain yield, and harvest index per plant of the component hybrids decreased as the proportion of YD13 increased under contrasting N and plant density combination. Despite different N and plant density combinations, competitive outcomes was invariant (i.e.,YD13 was always the superior competitor), the yield performance of ZD909 was always higher than YD13. When the plant density was held constant, N deficiency increased both inter‐cultivar competition and the degree of competitive asymmetry between YD13 and ZD909. When the N application rate was held constant, competition intensity intensified with increasing plant density; however, the degree of competitive asymmetry was reduced, mainly because the competitive advantage of the superior competitor (YD13) diminished at higher population densities. Our results suggest that N deficiency increases the competitive advantage of a superior competitor over a weaker competitor, but this advantage decreases in response to increased plant density. This probably implies that maize hybrids with weak competitiveness should be selected in breeding programs, especially under the condition of higher soil productivity and plant density, which is designated for dense‐planting and high‐yielding production.
Cotton Root Morphology and Dry Matter Accumulation at Different Film Removal Times
Authors: Yang Xiangkun , Zhang Zhanqin , Niu Yuan , Tian Haiyan , Ma Fuyu
Published: October 2017

Core Ideas

Film removal at an appropriate time can increase cotton root length, surface area, and volume.

Film removal is conducive to the accumulation of root dry matter in the year with less rainfall.

Film removal treatment promotes growth of hair roots and improves the root/shoot ratio.

A field experiment was conducted to examine the influence of mulch film removal time (10 and 1 d before the first irrigation (T10 and T1, respectively) and 1 d before the second irrigation (E1) after emergence) on cotton (Gossypium hirsutum L.) root morphology and dry matter accumulation. The control group (CK) was film mulched throughout the growth stage. In 2015, the respective root length density (RLD), root surface‐area density (RSD), and root volume density (RVD) in E1 were highest during the initial flowering stage (IFS, 3537 m m−3, 3.4819 m2 m−3, and 382 cm3 m−3) and blossoming and boll forming stage (BBFS, 2472 m m−3, 3.1307 m2 m−3, and 421 cm3 m−3). The maximum root dry matter accumulation was measured in CK (2647 kg ha−1). In 2016, which had more rainfall, RLD (1699 m m−3) and RSD (2.6877 m2 m−3) in T10 and RVD in T1 (503 cm3 m−3) were the highest during IFS. RLD in E1 (2234 m m−3), RSD (3.6770 m2 m−3) and RVD (598 cm3 m−3) in CK were the highest during BBFS. The cotton root/shoot ratio (R/T) was higher in the film‐removal treatments than in CK. E1 showed the highest proportion of fine roots thinner than 1.0 mm during any stage except for 2015 BBFS. The results indicate that film removal at an appropriate time can increase RLD, RSD, and RVD, but it is conducive to the accumulation of root dry matter only in years with lower rainfall.
Commercial Safened ALS‐herbicide Formulation Effects on ALS‐sensitive Field Corn Hybrids
Authors: Carter Oliver W. , Prostko Eric P. , Davis Jerry W.
Published: October 2017

Core Ideas

Corn hybrid sensitivity to ALS herbicides is an issue.

Herbicide safeners may not provide complete crop safety.

Growers who want to use safened ALS herbicides on sensitive corn hybrids must be aware of yield loss potential.

Research was conducted in 2014 and 2015 to determine if two common commercial acetolactate synthase (ALS) inhibitor herbicide formulations, that contain the crop safener isoxadifen, could be used on field corn (Zea mays L.) hybrids with reported ALS sensitivity. Two ALS‐sensitive field corn hybrids (DEKALB DKC 62‐08 and DKC 64‐69) were treated 18 to 21 days after planting with nicosulfuron + rimsulfuron + isoxadifen or thiencarbazone + tembotrione + isoxadifen at 1× and 2× labeled rates. No interactions were observed between herbicide treatment and field corn hybrid. When averaged over herbicide treatment, DKC 62‐08 produced less aboveground biomass and was shorter in height than DKC 64‐69. However, no difference in grain yield between hybrids was observed. When averaged over corn hybrid, only the 2× rate of tembotrione + thiencarbazone methyl + isoxadifen caused a significant reduction (19%) in aboveground biomass. Nicosulfuron + rimsulfuron + isoxadifen and tembotrione + thiencarbazone + isoxadifen, at both 1× and 2× rates, reduced plant height up to 3 inches 26 days after treatment (DAT). However, only the 2× rates of these safened herbicides caused significant height reductions 62 DAT. Both herbicide formulations at 1× and 2× labeled rates caused corn yield losses of 11 to 16 bu/acre. These data suggest that these particular commercial herbicide formulations can cause crop injury and subsequent yield loss when used on ALS‐sensitive field corn hybrids.
Potassium and Nitrogen Fertilization Effects on Jiggs Bermudagrass Herbage Accumulation, Root–Rhizome Mass, and Tissue Nutrient Concentration
Authors: Yarborough J.K. , Vendramini J.M.B. , Silveira M.L.A. , Sollenberger L.E. , Leon R.G. , Sanchez J.M.D. , Leite de Oliveira F. , Kuhawara F. , Cecato U. , Soares Filho C.V.
Published: October 2017

Core Ideas

Bermudagrass K fertilization affects forage characteristics.

Bermudagrass K fertilization effects are influenced by N fertilization.

K fertilization is crucial to increase belowground reserves of bermudagrass.

Adequate supply of potassium (K) is an important factor that can affect bermudagrass [Cynodon dactylon (L.) Pers.] production and persistence, particularly in soils with limited nutrient holding capacity. The objectives of this study were to (i) evaluate the effects of different nitrogen (N) and K fertilization strategies on Jiggs bermudagrass herbage accumulation (HA), root–rhizome mass, and K concentration and accumulation in above‐ and belowground tissue; and (ii) identify the critical minimum tissue K concentration below which bermudagrass HA is reduced. The experiment was conducted in a greenhouse at Ona, FL, from August to December, 2014 and 2015. Treatments were a factorial combination of three N (0, 45, and 90 lb/acre) and four K2O fertilization levels (0, 18, 36, and 72 lb K2O/acre, the equivalent of 0, 15, 30, and 60 lb K/acre) after every harvest, distributed in a completely randomized design with four replicates. Herbage was harvested every 6 weeks, and root and rhizome mass determined at the end of each year. There were no effects of K fertilization on HA and root–rhizome mass when no N was applied; however, Jiggs HA and root–rhizome biomass increased linearly with increasing K fertilization levels at 45 and 90 lb N/acre. For these N levels, HA increased with tissue K concentration up to 1.4%. Root and rhizome K concentrations decreased linearly with increasing levels of N. Conversely, root–rhizome K content increased with increasing levels of N fertilization. Potassium fertilization increased HA and root–rhizome mass of Jiggs bermudagrass; however, the responses were influenced by N fertilization levels.
Endosperm Carbohydrates and Debranching Enzyme Activity in Five Native sugary1 Alleles in Maize
Authors: Shuler Stacie L. , Boehlein Susan K. , Hannah L. C. , Tracy William F.
Published: October 2017

The su1‐ref allele, the only mutant used in sweet maize (Zea mays L.) until the 1960s, continues to be used in sweet maize improvement programs. Wild‐type Su1 encodes the starch debranching enzyme (DBE) isoamylase1 (ISA1) that is required for amylopectin production. Loss of Su1 function also leads to a reduction in activity of another DBE enzyme, pullulanase. Five naturally occurring su1 mutations have been identified and characterized as having different carbohydrate compositions. The alleles have not been evaluated for isoamylase and pullulanase DBE activity or for mature kernel composition of hybrid allele combinations. The five su1 alleles were backcrossed into two field corn lines, A619 and A632. The resulting inbreds were crossed in a factorial design. The hybrids were grown in 2015 and 2016 in Madison, WI, for an evaluation of mature kernel composition. In 2016, the su1 inbreds were grown and immature tissue was harvested 21 d after pollination for enzymatic analysis. Significant differences were identified among the su1 hybrids for starch and water‐soluble polysaccharides (WSP). Hybrids containing the su1‐p allele consistently accumulated the greatest amount of starch and the lowest amount of WSP, and those with the su1‐ne allele had the lowest amount of starch and greatest WSP content. No significant differences were observed among the su1 inbreds for isoamylase or pullulanase activity. Little to no isoamylase activity was observed, whereas pullulanase activity was reduced among the su1 mutants compared with the wild type, Ia453‐Su1. Our data indicated that differences in starch and WSP observed among the su1 alleles was not due to isoamylase or pullulanase DBE activity.
Two Dimensional Modelling of Nitrate Flux in a Commercial Apple Orchard
Authors: Hardie Marcus
Published: October 2017

Core Ideas

15 to 33% of rainfall was lost as runoff or drainage under rainfed conditions.

Current management of young trees resulted in loss of 46% applied nitrate.

Drip fertigation was predicted reduce drainage and nitrate leaching by 37%.

Excluding the use of green fowl manure reduced nitrate leaching by 56%.

Deficit‐based irrigation scheduling had little effect on nitrate leaching.

Extensive in situ monitoring in a young commercial apple orchard demonstrated that current management practices resulted in leaching of 56 to 84 kg ha–1 yr–1 of nitrate below the topsoil. The Hydrus 2D/3D suite of models was used to determine the effect of current management practices on nitrate leaching and explore options for reducing irrigation and nitrate loss. The models were parameterized using measured soil water retention data and calibrated using field data collected over a 596‐d period. The orchard was found to be profoundly ‘leaky’ with between 15 and 33% of the average annual rainfall being lost via runoff and deep drainage under rainfed conditions. Simulations estimated that the current management of the young trees resulted in loss of 38.1 kg N ha–1 yr–1 or 46% of the applied nitrate, and 34.6 cm yr–1 of rainfall and irrigation as drainage below 2.0 m depth. For mature trees, our model scenarios predicted that converting from sprayers to drippers, would reduce the required irrigation by 44%, reduce nitrate requirement by 21%, and reduce deep drainage and nitrate leaching by 37%. Deficit‐based irrigation and fertigation scheduling had minimal effect on the amount of deep drainage and nitrate leaching. In mature trees, excluding green fowl manure from the fertilizer regime was predicted to reduce the amount of nitrate leached below the soil profile by 12.9 kg N ha–1 yr–1 or by 73%. However rates of NPK and fertigation needed to be increased to meet tree nitrogen demand.
Method to determine test profile in accelerated reliability demonstration test under Type-I censoring
Authors: Li Peng , Li Yuxiang , Dang Wei
Published: October 2017

Conventional reliability demonstration test (RDT) based on statistical method is widely used in industry as it is simple and convenient to apply. But for products with high reliability and long life, this test method fails to satisfy the demand for short cycle and low cost, and is liable to cause the phenomenon of over-test and short-test. This paper gives a method to determine the accelerated stress profile for RDT under multiple stresses and mechanisms, making it faster to make decision of accept or reject. By raising the levels of sensitive stresses that the product would experience, the test time can be cut down remarkably. We can derive the overall acceleration factor based on the narrow reliability bounds theory. Then we choose the test plan referring to GJB 899A. Furthermore, combined with the reliability qualification test (RQT) profile, the accelerated test profile is acquired. An example is given to illustrate the superior performance of the proposed method over traditional methods.
Multivariant linear regression model based response prediction in situation of unknown uncorrelated multiple sources load
Authors: Zhan Wei , Wang Cheng
Published: October 2017

In order to predict response in the situation of unknown uncorrelated multiple sources load, a new response prediction method in frequency domain is proposed. The algorithm needs no transfer function and straightforwardly looking for the inner link between the known responses and the unknown responses. In the multivariant linear regression model, the vibration data of known measuring points are used as input and the vibration data of the unknown measuring points are used as output. And the parameters of multivariant linear regression model are solved by historical training data and the least squares generalized inverse. Experiment verification results of acoustic and vibration sources on cylindrical shell showed that the proposed approach could predict vibration response effectively and satisfy industrial requirements.
The active control of macro-fiber composite over harmonic vibration of arc-plate structures
Authors: Wei Jianhui , He Weiping , Tu Jianwei , Zhang Jiarui , Luo Wei
Published: October 2017

This paper offers an actuating equation for MFC arc-plate structures to obtain MFC’s accurate actuating force and actuating bending moment to are-plate structures and increase MFC control effect on vibration. This paper proposes the P1 type MFC arc-plate actuating equation which considers the recombination action of MFC and controlled structure, and arc-plate curvature influence on MFC, obtaining the MFC actuating force and actuating bending moment for arc-plate structures. The vibration control experiment of MFC arc-plate structures is performed, and the deviation between finite element simulation results adopting this equation and the experimental data is less than 8.5 %. The research shows that the P1 type MFC actuating equation deduced in this paper is correct and fully applicative to the MFC vibration control simulation to arc-plate structures.
A scaled experimental research on reducing metro railway vibration by using trench and barriers
Authors: Zhang Hougui , Qin Chong , Kang Zhongxu , Liu Qiang
Published: October 2017

In order to research on reducing vibration by using trench and barriers at the vibration transmission path, the presented paper introduced a test campaign in a 1:5 scaled benches. The tests were conducted for four different conditions, including the control condition, open trench, concrete barriers, and concrete barriers with PUR mat. Findings indicated that the specific barriers made of concrete with elastic PUR layer can indeed efficiently reduce the transmission through the soil of vibrations.
Multiple random fault sources adaptive blind separation in situation of time-varying source signals and system
Authors: Wang Cheng , Hu Yanxia , Zhan Wei , Wang Jianying , Yang Baokun , Zhang Yiwen , Chen Yewang
Published: October 2017

In order to separate multiple random fault source signals adaptively only from mixed vibration measurement signals of mechanical system in the situation of time-varying source signals and mixture system, two adaptive blind identification and separation methods are proposed to solve this kind of problem. One is based on recursive least squares (RLS) algorithm and another is based on recursive EASI algorithm. The simulation results show that both of these methods can separate source signals from the mixed signal in the situation of time-varying source signals and mixture system very well.
Research on natural frequency of structure considering elastic joint with interval uncertainty
Authors: Chen Jiangpan , Liu Yan , Wang Dong , Zhang Weiwen , Liu Xu
Published: October 2017

An efficient method, namely fixed interface mode synthesis-interval factor method (FIMS-IFM), is proposed to calculate the natural frequency of structure considering elastic joint with interval uncertainty. In this proposed method, the interval uncertain elastic joint is treated as spatial beam element with interval uncertain material parameters. Additionally, both the proposed method and Monte-Carlo simulation method are used to calculate the natural frequency of a specially designed structure with interval uncertain elastic joint. A meaningful conclusion can be acquired via comparing the calculation results of the two methods that, FIMS-IFM is correct and high-efficiency.