bluuebunny/crossref_metadata_2025 huggingface dataset:
A Case Study of Formation Testing in Antelope Shale
Authors: Lal Manish K. , Tran Viet H. , Singh Amit
Published: April 2017

In new shale development, formation testing is critical to understanding reservoir properties and producibility. However, due to low permeability, a test usually takes much longer and can easily result in cost overruns. There are many ways to conduct formation testing such as drill pipe / tubing conveyed testing and coil-tubing or wireline testing. Formation wireline testing has advantage not only for its flexibility and combinable features but also for cost and time savings as compared to other methods. In a combination way, formation wireline tool can be run either through wireline alone or through the drill pipe for safety reasons.

The Antelope Shale in Monterey Formation in San Joaquin Valley is siliceous shale that is thinly laminated, has relatively high porosity, low permeability, small pore throats, and varying degree of fracturing. Siliceous shale hydrocarbon reservoirs are not very common and little is known about their production characteristics. These are much more geologically complex than the conventional shale and tight rock reservoirs and the traditional conventional formation testing methods may not be directly applied to them. Little or no literature review can be found on running formation evaluation wireline tools in the Antelope Shale.

In this paper, we discuss a case study of formation testing in Antelope Shale. The test was run with dual packers and downhole fluid analyzer in a vertical appraisal well to evaluate two intervals in the Antelope Shale. The run proved the value of formation testing method in terms of data collected versus cost & time. First, the drill pipe conveyed formation testing was selected among different methods to help characterize the reservoir and to measure fracture closure pressure to evaluate technologies that can lead to the development of tight reservoirs. Second, the microfracturing data collected from the formation testing job was used for designing the completion strategy to understand individual zone production such that we may target a single zone for future development. The additional values of the formation test were to measure formation pressure and collect fluid samples for Pressure, Volume, and Temperature (PVT) analysis to minimize uncertainties in key reservoir parameters.

The job proved its pivot values for formation testing. However, the experience from planning and running the tool in this new tight rock reservoir are much more important to achieving the appraisal objectives. The combinable features of the tool enabled continuous onsite monitoring, on-the-fly operational decision making in sample depths in response to formation behavior, and optimizing sample chamber opening time to collect critical oil and water samples, while successfully acquiring the fracture closure pressure. These results may be difficult to achieve with other methods in a single run.
Steady-State Relative Permeability Upscaling in Multiporosity/Multipermeability Core Assemblages
Authors: Ramsay Travis , Hinkley Richard
Published: April 2017

Steady-state two-phase relative permeability upscaling in synthetic and X-ray computerized tomography (CT) coal cores is performed with a three-dimensional (3D) reservoir simulator using an automated control procedure to drive a series of steady-state fractional flows. A clear understanding of relative permeability in coal is important for coalbed methane reservoir management from pore scale to sales point, as it is valuable for helping forecast production. Automation control enables greater continuity between physical corefloods and the numerical upscaling of the same coreflood procedure. Absolute permeability is computed for primitive synthetic core types using the reservoir simulator and is compared to an analytical formulation to validate the use of the simulator solution for core scale property determination.

Relative permeability was computed for synthetic cores considering several scenarios: fracture geometry/abundance (parallel vs. intersecting), rock-type matrix distribution (homogeneous vs. heterogeneous), ratios of matrix-to-fracture permeability (high vs. low), and injection rate conditions [capillary limit (CL) vs. viscous limit (VL)]. Additionally, injection rate conditions were evaluated in the upscaled relative permeability of an X-ray CT segmented composite coal core. Analysis of the upscaled relative permeability curves in the composite and synthetic cores illustrated the impact of each scenario on upscaling relative permeability and suggests that selected characteristics of unconventional cores can potentially be used to delineate parameter dependence in a manner similar to rock type volume fraction and ordering in conventional cores. The consistency of the developed upscaled results with previous studies confirms the applicability of automated process control in core scale multiphase upscaling using a commercial reservoir simulator at varied injection rates and upscaling conditions.
An Experimental Study of CO2 Saturated Brine Reaction with Berea Sandstone
Authors: Chen Peng , Saeedi Ali , Noble Ryan
Published: April 2017

Geological sequestration of CO2 is one of the most promising technologies to mitigate the greenhouse effect by decreasing the anthropogenic CO2 emissions into the atmosphere. Deep saline reservoirs are a suitable target for CO2 storage because very often they can be found relatively close to today's large CO2 releasing sources. To investigate the chemical and physical impacts of a CO2-rich brine solution injection to a quartz rich sandstone, we flooded a Berea Sandstone core sample with CO2-saturated synthetic brine at the elevated temperature (60°C) and pressure (20MPa). After flooding, the porosity and permeability of the core were measured and compared to the pre-flooding values. We found that the porosity had increased by 1.8% while the permeability decreased by 5.1%. The decrease in permeability may be attributed to the movement of particles in the pore space of the sample (fines migration) and/or sample's physical compaction under net effective stress. Effluent brine samples were also collected during the core-flood experiment to be analysed for their chemical composition. We found that, on average, the concentration of Ca2+, Mg2+ and Fe2+ in the effluent samples to increase by approximately 100mg/l, 80mg/l and 95mg/l, respectively, with traces of other metals. It is believed that the Ca2+, Mg2+ and Fe2+ were liberated from the dissolution of the carbonate cement in the sample. As revealed by the differential pressure evolution of the experiment, for the quartz-rich sandstone reservoirs, where fines migration is not significant and reactive minerals are scarce, the injectivity may not be affected during the fluid injection process.
A Real-Time Interactive Drill-Off Test Utilizing Artificial Intelligence Algorithm for DSATS Drilling Automation University Competition
Authors: Bilgesu H. , Cox Z. D. , Elshehabi T. A. , Smith C. , Idowu G. O. , Florence F. R.
Published: April 2017

The current state of the drilling industry tends to focus on technology and techniques that reduce the cost of well construction. One approach is to use drilling automation to help improve ROP, and perhaps more importantly, to mitigate drilling dysfunctions and human errors than can lead to large, unplanned expenses. SPE's Drilling Systems Automation Technical Section (DSATS) created an international university competition to encourage the development of new drilling algorithms and to get more young people involved in drilling. The students must design, build and operate a small (6 ft / 2 m) drilling rig with fully automated sensors and controls. They drill a specially created, multi-layered rock sample as fast and as straight as possible, with only two buttons: start and stop. This paper summarizes the work done by the West Virginia University team that won the 2016 competition. It shows scalable drilling algorithms can be developed on a miniature rig that can later be transferred to ongoing drilling programs.

DSATS implemented a competition to encourage students to investigate the use of automation techniques and tools for drilling systems. The competition fosters a greater understanding of complicated drilling systems, challenging students across disciplines to consider the possibilities of a career in upstream drilling operations. This project requires each university team to first submit a proposal, including structural design, control architecture, and sensor selection with no knowledge of the material to be drilled. Teams were advised to consider mitigating the effect of nonplanar junctions as well as the possibility of lost circulation, and to be especially cognizant of vibration and torque issues. The winning team received a travel grant to attend the ATCE to present their test results at the DSATS symposium in Dubai.

This paper addresses the details of that presentation. It includes: Drilling limitations and critical parametersConstruction issues and initial operations that required a re-designFinal design criteria, constraints, tradeoffsSummary of recorded data and key eventsDrilling parameters and how they impacted the testEconomic considerationsSignificant lessons learnedConclusions and recommendations

As the competition finishes its second year, it remains the only competition of its kind that requires a multidisciplinary approach at a university level, and prepares those involved for the type of interwoven, team approach often at the heart of oilfield operations today. While the rig designs are practical, they are not limited by historical features or commonplace rig designs.

Hands-free drilling is possible and proven on a small scale as more and more companies begin to implement full scale operations to mitigate drilling dysfunctions and improve ROP to lower costs.
Making Sense of Why Sometimes Logs Do Not See Cement in the Annulus
Authors: Kalyanraman Ram Sunder , Van Kuijk Robert , Hori Hiroshi
Published: April 2017

Ultrasonic and sonic logs are commonly used to evaluate the quality of cement placement in the annulus of a pipe and its potential to perform as a barrier. In some cases, we observe that the log response is in conflict with the expectations on the outcome of the cementing job that was executed without any major issues. The log sometimes does not see the cement! This apparent disagreement if not resolved could potentially lead to costly and unsuccessful attempts to remediate the cement sheath. We highlight reasons why sometimes logs may not see the cement and implement new workflows that not only recognize these factors but also account for it in the cement sheath evaluation.

The ability to recognize the existence of a wet or dry micro-annulus is critical for cement sheath evaluation and is discussed through two new interpretation workflows using ultrasonic and sonic logs. Firstly, we introduce a new ultrasonic (TIGHT model) interpretation workflow that improves discrimination of light-weight solids from displaced muds and enables identification of dry micro-annulus situations. Secondly, we introduce a new integrated workflow that combines sonic amplitude / attenuation with ultrasonic measurements in the acoustic impedance (AI) space (Sonic vs ultrasonic acoustic impedance). Through this approach, we demonstrate how we can identify cement that is well bonded and discriminate from those with a dry or a wet micro-annulus.

The workflows were applied to data acquired in wells where we compared the results of conventional interpretation approaches as well as those discussed in the two workflows. The gap caused by the detachment of cement from casing (de-bonded cement), either wet or dry micro-annulus, can affect the log responses differently and sometimes significantly. The effect of micro-annulus on logs can be recognized which then facilitates correct assessment of the cement sheath behavior. We note that the log response in the presence of a dry micro-annulus may be different to that for a wet micro-annulus. In the case of a dry micro-annulus, even with relatively smaller gaps between cement and casing, conventional approaches to interpretation of the sonic and ultrasonic logs can completely miss "seeing" the cement.

We observe that the integration of ultrasonic and sonic measurements through these workflows has the potential to improve the quality and reliability of cement evaluation when cements de-bond from casing. The ability to do so with existing ultrasonic and sonic technology not only helps improve confidence on cement sheath evaluation but also has the potential to reduce unwanted and costly remediation decisions.
Organic and Inorganic Formation Damage Removal Using Customized Formulations
Authors: Quintero Lirio , Newberry Michael , Morales Rosanel , Davis Chelsea
Published: April 2017

Paraffin and asphaltenes deposits, scale deposits and emulsions formed by fluids incompatibility in oil-producing wells, and other formation damage mechanisms are a major cause of loss of well productivity.

Organic and inorganic deposits can occur on the surfaces of well tubing and within the pores of the near-wellbore formation, reducing of flow efficiency and possibly blocking the flow paths completely. The damaging process may occur naturally during the production phase of the well or it can be triggered during wellbore intervention treatments or even during the wellbore construction stage.

In general, formation damage is driven by more than one mechanism. A thorough assessment and diagnosis of the fundamental cause(s) of the formation damage is important to properly select the best remediation treatment and procedure. Even if there is no standard, best practices and methodologies to diagnose the cause(s) of the formation damage and evaluate potential chemical treatments have been developed.

A discussion of the improved methods of problem identification, programs to remediate these problems, and stimulation software will be described in this paper. A synopsis of the potential causes that generate organic and inorganic deposits in the wellbore, diagnosis of formation damage, chemical treatment selection and applications are also discussed.

Laboratory test evaluations and smart selection of chemical treatment, according to the type of formation damage, are presented, along with number of example case histories.

Diagnosis of organic and inorganic formation damage, problem identification using production history data, reservoir and fluid properties, well configuration, and history of well intervention and/or stimulation that allowed tailoring customized formulation proved that this approach resulted in better wellbore cleanup and production increase.
Assessment of Rate Transient Analysis Techniques for Multiphase Flow in Unconventional Reservoirs: Application to Eagle Ford Formation
Authors: Uzun Ilkay , Eker Erdinc , Cho Younki , Kazemi Hossein , Rutledge J. M.
Published: April 2017

In reservoir evaluation of unconventional reservoirs, engineers use rate transient analysis (RTA) to assess the performance of hydraulically fractured horizontal wells. This technique consists of plotting rate- normalized pressure drop at the well sandface versus square root of time (i.e., linear flow) to calculate the reservoir effective permeability. In this paper, we report on the use of an in-house multiphase numerical simulator applied to production data from several Eagle Ford wells to assess both single- and multi-phase production performance. Furthermore, a combination of numerical simulation and analytical solution techniques was used to validate the information obtained from the RTA in the Eagle Ford wells. This procedure further improved our insight into the flow behavior of unconventional reservoirs. The multi-phase effective permeability calculated from the RTA was within a few percent of the input data to the numerical model. Furthermore, the multi-phase RTA results produce more accurate than the conventional single-phase RTA approach; and the multi-phase analysis results were more in line with the well performance observations than with when using the single-phase analysis approach. Furthermore, the multiphase results were more consistent with the success or failure of the hydraulic fracturing process.
An Empirical Model to Estimate a Critical Stimulation Design Parameter Using Drilling Data
Authors: Atashnezhad Amin , Cedola Alexandra E. , Hareland Geir
Published: April 2017

Hydraulic fracturing is the stimulation process during which fractures are created by pumping mostly water and sand into the formations. Hydraulic fracturing is done on almost 90% of gas wells in the United States. Selectively determining the fracturing intervals along the borehole is one of the most critical factors for optimizing stimulation and maximizing the net present value (NPV) of the well. In this study, an empirical model was developed to predict the formation porosity using surface drilling data and gamma ray (GR) at the bit without needing log data.

In this study, data from three wells were used to develop an empirical model for porosity prediction through the use of drilling data. To find the best model, a differential evolution algorithm (DE) was applied to the space of solutions. The DE algorithm is a metaheuristic method that works by having a population of solutions, and it iteratively try to improve the quality of answers by using a simple mathematical equation. The developed model uses the unconfined compressive strength (UCS) obtained from an inverted rate of penetration (ROP) model and gamma ray (GR) at the bit to estimate the formation porosity.

Data from three offset wells in Alberta, Canada were evaluated to find a porosity estimation model. The DE algorithm was used to search the infinite space of solutions to find the best model. The models reliability and accuracy were studied by conducting a sensitivity analysis then comparing the results to offset well data. There is good agreement between the models estimated porosity and porosity from the well log data. This paper presents results from individual well sections that compare the neutron porosity from logs in the field to the calculated porosity obtained from the newly developed correlation. The results show accurate quantitative matching as well as trends. The model presented can be applied to horizontal wells where the porosity can be mapped in addition to the UCS value from the drilling data at no additional cost. Based on this formation mapping log, optimum fracturing interval locations can be selected by taking the UCS and porosity of a formation into account. The suggested approach can also be used to determine the porosity in real-time.

The novelty of this model is in the ability to estimate porosity using typically collected drilling data potentially in real time. By applying this model, there is no need for well services such as well logging to find hydraulic fracturing points, which significantly reduces the cost and time associated with the well completion operation.
Use of Decline Curve Analysis for Application of Production Enhancement Treatments in Heavy Oil Reservoirs
Authors: Castro Leo
Published: April 2017

In an environment of soft to declining oil prices, the key to survival for many operators is maintaining production on current producing wells. Stimulating current producing wells is one way of maintaining that production, although the type of stimulation treatment may not always be straightforward. This paper presents strategies for the identification of stimulation candidate wells, and chemical treatment types that will present the best opportunities to increase production based on the specific type of damage mechanism encountered.

The use of decline curve analysis is an important tool in selecting wells for production enhancement. In a day where precious few dollars are available for production enhancement and a long term study for candidate identification is not feasible, it is of particular importance to have the tools readily available to identify and select only those wells that will not only minimize the risk of the expenditure, but also yield justifiable economic returns.

Extensive field experience has identified production profiles that are consistent with different types of damage mechanisms found in the heavy oil environment. Learning to recognize the profiles and the damage that triggered those profiles, will help the production engineer or coordinator decide on the best treatment technique.

This paper discusses the different types of damage profiles observed on production plots, and details the damage mechanisms that caused that damage profile and the treatment products and techniques necessary to restore a well's production to its full potential.
Investigating Impact of Various Properties on Relative Permeability and Non-Wetting Phase Fractional Flow in Brine/Oil System in Water-Wet Reservoir Rock by Numerical Simulation
Authors: Jahan Farjana , Hossain Md Mofazzal , Ahmed Shakil , Iglauer Stefan
Published: April 2017

In this paper, pore-scale numerical modelling predictions are performed to investigate variations in relative permeability behaviour and oil fractional flow under a range of different parameters (contact angle, capillary number and flow direction) through Brine/Oil system in Ottowa F42 Sand Pack. AVIZO (high-performance 3D image processing software) is used to separate the Micro-computed tomography (micro-CT) images of the pore spaces of rocks from grains of Ottowa F42 Sand Pack. ANSYS-CFX (high- performance CFD based simulator) is used to generate volume mesh and carry-out numerical simulation. The simulation results were analysed and compared with other experimental and numerical works. At low capillary number, the relative permeability curves were not smooth. Almost similar trends for relative permeability were observed for the imbibition process by alternate injection of oil and brine. Increase in contact angle showed less effect on fluid relative permeability and oil fractional flow. Also, alternate injection of fluids in imbibition showed a little response on fluid relative permeability and oil fractional flow. The outcomes of this investigation will be extended to intermediate-wet and oil-wet media and also for carbonate formations.
The Patented HyperScratcher Workover Tool – Increasing Production on Existing Wells
Authors: Tuttle John D.
Published: April 2017

The patented HyperScratcher workover tool has recently been reintroduced for use on well workovers in the San Joaquin Valley, Santa Maria Valley and LA Basin. Originally designed, developed and applied successfully in California during the industry downturn of the mid-1980s, the use of this unique tool to clean perforated and slotted liners often resulted in significant production increases. This was a critical goal for Operators during periods of depressed oil prices, when drilling was curtailed and production from existing wells was a primary goal.

This paper will introduce the working components of the HyperScratcher ‘Production Enhancement’ tool, explain how the tool is applied in the field, specific operating considerations, and identify methods to select potential well candidates. Differing well types will be discussed (producers, injectors, water source wells), along with a brief review of past projects and the potential for improvements in well performance. In addition, case histories and results from recent California and other domestic experiences will be shared to validate the claims of the technology.

With key considerations patented in 2013, the HyperScratcher workover tool has been reintroduced to the West Coast workover market during the past year, and when applied on underperforming or damaged wells with perforated or slotted liners, the technology has consistently provided enhanced production or injection capabilities. These results have been obtained during regularly planned workovers of existing wells.
Expression Patterns of ACS and ACO Gene Families and Ethylene Production in Rachis and Berry of Grapes
Authors: Ye Xia , Zheng Xianbo , Zhai Dehua , Song Wen , Tan Bin , Li Jidong , Feng Jiancan
Published: April 2017

Ethylene is important during the berry development and in the last stages of rachis development or rachis senescence. Since grapes develop in a cluster that comprises both the fruit berry and the nonfruit rachis, we measured the release of ethylene from both tissues. Detached berries from Vitis vinifera ‘Ruby Seedless’ and ‘Thompson Seedless’ showed that ethylene release peaks at the beginning of berry development and at veraison. Ethylene production in the rachis was higher than that in the berry and had an obvious peak before harvest in ‘Thompson Seedless’. In both cultivars, ethephon treatment induced ethylene production in the rachis but not in the berry. Expression of 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS) and ACC oxidase (ACO) genes showed diverse temporal and spatial patterns in ‘Thompson Seedless’ and ‘Ruby Seedless’. For most gene family members, the low ACS expression levels were observed in berry and rachis. Expression levels of most of the ACS and ACO genes did not correlate with ethylene released in the same organ. The transcriptional level of VvACS1 did correlate with ethylene evolution in rachis of ‘Thompson Seedless’ during berry development and storage, which suggested that VvACS1 may have important roles in rachis senescence. In berries of ‘Thompson Seedless’ and ‘Ruby Seedless’, the transcriptional levels of VvACO1, VvACS2, and VvACS6 coincided with ethylene production, indicating possible roles in berry development. Expression of VvACS2–VvACO9 and VvACO1–VvACO3 was not consistent with ethylene production during storage or in response to ethephon treatment, which suggests that the expression of ACS and ACO was affected by other stress factors after harvest.
Seedling Growth Is Similar under Supplemental Greenhouse Lighting from High-pressure Sodium Lamps or Light-emitting Diodes
Authors: Poel Brian R. , Runkle Erik S.
Published: April 2017

Light-emitting diodes (LEDs) have the potential to replace high-pressure sodium (HPS) lamps as the main delivery method of supplemental lighting (SL) in greenhouses. However, few studies have compared growth under the different lamp types. We grew seedlings of geranium (Pelargonium ×hortorum), pepper (Capsicum annuum), petunia (Petunia ×hybrida), snapdragon (Antirrhinum majus), and tomato (Solanum lycopersicum) at 20 °C under six lighting treatments: five that delivered a photosynthetic photon flux density (PPFD) of 90 μmol·m−2·s−1 from HPS lamps (HPS90) or LEDs [four treatments composed of blue (B, 400–500 nm), red (R, 600–700 nm), or white LEDs] and one that delivered 10 μmol·m−2·s−1 from HPS lamps (HPS10), which served as a control with matching photoperiod. Lamps operated for 16 h·d−1 for 14 to 40 days, depending on cultivar and season. The LED treatments defined by their percentages of B, green (G, 500–600 nm), and R light were B10R90, B20R80, B10G5R85, and B15G5R80, whereas the HPS treatments emitted B6G61R33. Seedlings of each cultivar grown under the 90 μmol·m−2·s−1 SL treatments had similar dry shoot weights and all except pepper had a similar plant height, leaf area, and leaf number. After transplant to a common environment, geranium ‘Ringo Deep Scarlet’ and petunia ‘Single Dreams White’ grown under HPS90 flowered 3 days earlier than those grown under HPS10, but flowering time was not different from that in LED treatments. There were no consistent differences in morphology or subsequent flowering among seedlings grown under HPS90 and LED SL treatments. The inclusion of white light in the LED treatments played an insignificant role in growth and development when applied as SL with the background ambient light. The LED fixtures in this study consumed substantially less electricity than the HPS lamps while providing the same PPFD, and seedlings produced were of similar quality, making LEDs a suitable technology option for greenhouse SL delivery.
Managing Apple Crop Load and Diseases with Bloom Thinning Applications in an Organically Managed ‘Honeycrisp’/‘MM.111’ Orchard
Authors: Peck Gregory M. , DeLong Candace N. , Combs Leon D. , Yoder Keith S.
Published: April 2017

Although demand for organic produce continues to increase in the mid-Atlantic, few apple (Malus ×domestica Borkh.) growers in the region have adopted organic management practices due to the considerable disease, insect, and weed pressure, as well as the lack of effective crop load management tools. In this study, lime sulfur (LS) and Regalia® (R) were applied in different sequences (i.e., LS/LS, LS/R, R/R, and R/LS), each in a mixture with JMS Stylet-Oil, to chemically thin apple flowers in an organically managed ‘Honeycrisp’/‘MM.111’ orchard. There was also a nontreated control, a “grower standard” control (LS at 11 mm fruitlet diameter), and a hand-thinned control. The treatments were evaluated for their ability to reduce crop load, as well as to control powdery mildew [Podosphaera leucotricha (Ellis & Everh.) E. S. Salmon], cedar apple rust (Gymnosporangium juniperi-virginiana Schwein.), and quince rust (Gymnosporangium clavipes Cooke & Peck). All treatments reduced crop load compared with the nontreated control, and after the first application of LS or R, the number of fertilized king blooms was reduced and fertilization was prevented in all side blooms. All bloom thinning treatments had more fruit peel russet than the control and russet was more severe when LS was one of the applications. Bloom thinning applications of LS and R did not reduce powdery mildew leaf infection compared with the nontreated control. Cedar apple rust incidence was reduced by all bloom thinning treatments, though some lesions were detected in all treatments. There were minimal quince rust infections in any of the treatments, including the nontreated control. These results suggest that when LS and/or Regalia® are mixed with JMS Stylet-Oil and applied as bloom thinners, they can reduce crop load, and, as a secondary benefit, they can also decrease cedar apple rust incidence from infections that occur during bloom.
Deficit Irrigation in Vitis labruscana Bailey ‘Concord’ in Central Washington
Authors: Stout Jason E. , Davenport Joan R. , Peters R. Troy
Published: April 2017

Drought conditions in the western United States have limited water availability for the irrigation of agricultural products. This can have a dramatic impact on yield and quality of specialty perennial crops, such as juice grapes (Vitis labruscana Bailey). Washington State juice grape industry typically irrigates to 100% of crop-specific evapotranspiration (ETc) throughout the season to minimize yield loss. However, as conditions have limited water availability, growers need a new strategy to cope with the limited water supply. Regulated deficit irrigation (RDI) applies less water than plant ETc and has been shown to improve fruit quality in red wine grapes (Vitis vinifera). The objectives of this study were to evaluate the effects of RDI treatments on the yield and quality of ‘Concord’ juice grapes as compared with current commercial practice. The treatments reduced the amount of water applied between bloom and veraison by 25% (−25%), 33% (−33%), and 45% (−45%) from the control application. The results of this 4-year study initially indicated a dramatic decrease in yield in the −45% treatment (7.5 Mg/ha) as compared with the control treatment (19.2 Mg/ha); however, yield for the RDI treatments recovered in the subsequent seasons and was not statically different from the control. There were no statistical differences in fruit quality between treatments. This indicates that RDI has the potential to decrease water applied between bloom and veraison without impacting fruit quality; however, to avoid a sudden decrease in yield, it would be necessary to gradually reduce water applications over several years.
Cooling Performances on Rainless Days of Extensive Green Roofs Planted with Different Ornamental Species
Authors: Lin Yann-Jou , Su Ai-Tsen , Lin Bau-Show
Published: April 2017

This study investigated the cooling performances of extensive green roofs (EGRs) planted with 12 ornamental plants on rainless days in a subtropical city for 1 year. Imitating the construction of an EGR, 48 modules were constructed and each module was planted as a monoculture with 100 plants each. Plant growth and greening performance were measured every 2 weeks. Temperatures, solar radiation intensities, and substrate water contents were measured continuously and recorded every 5 minutes. The analyzed results showed that both plant species selection and seasonal variation had a significant impact on the noontime cooling benefit. The modules planted with taller plants, more extensive plant cover, higher albedo, and greater canopy volume had a greater noontime cooling benefit. As the seasons changed, the albedo and canopy volume of the modules were primarily responsible for differences in the noontime cooling benefit provided by the different plant species. Over an entire year of observation, the results of this research could inform the selection of plant species by landscape designers for EGRs with the aim of providing greater cooling benefits and aesthetic quality overall four seasons.
Formulating a Natural Colorant Containing Wax for a One-step Color-add Application for Fresh Citrus
Authors: Sun Xiuxiu , Baldwin Elizabeth , Ritenour Mark , Hagenmaier Robert , Bai Jinhe
Published: April 2017

In Florida, early season citrus fruits usually reach full maturity in terms of internal quality while their peel often does not turn to orange color after degreening due to insufficient buildup of carotenoids. For huanglongbing (HLB)-affected orange trees, the fruit may never turn orange during the entire harvest season, despite any cold weather. Improvement of early season citrus peel color is important to the citrus industry to better meet consumer expectations. Occasionally, packinghouses apply a dye, Citrus Red No. 2 (CR2), to improve the surface color of oranges, temples, and tangelos before applying a fruit wax to impart shine, retain moisture, and slow fruit senescence. In a previous report, we determined that paprika and annatto extracts are comparable to CR2 as natural colorant alternatives. In this research, the goal was to formulate a natural colorant [annatto, paprika, or paprika oleoresin (PO)]-containing carnauba wax coating. The coatings were first evaluated for color, shine, moisture retention, respiration rate, ethylene production, and internal gas content. Control fruit were coated with carnauba wax alone, or dyed with CR2 then coated with carnauba wax. The effects were assessed under different temperature and light exposure conditions to simulate commercial storage and marketing. The results showed that a one-step application of paprika-containing carnauba wax was comparable to the two-step (“CR2 then wax”) applications in improving fruit appearance and modification of internal gas composition.
Response of Young Pecan Trees to Irrigation in a Humid Climate
Authors: Wells Lenny
Published: April 2017

The prolonged period from tree planting to first commercial harvest of pecan [Carya illinoinensis (Wangenh.) K. Koch] provides incentive for many growers to intensively manage young trees to induce commercial production as soon as possible. This management includes irrigation. However, there remain very few data regarding the irrigation requirements of young pecan trees grown under southeastern U.S. orchard conditions. The objectives of this study were to determine appropriate irrigation rates for young pecan trees and to compare growth of young pecan trees with drip and microsprinkler irrigation. Parameters evaluated for both experiments include trunk diameter growth, stem water potential (water stress), leaf area, leaf length, leaf width, and chlorophyll index. These results suggest that irrigation is beneficial to the growth, vigor, and alleviation of water stress on young pecan trees in the establishment phase grown in the temperate region of the southeastern United States. There was no difference in young pecan tree growth and vigor for microsprinkler irrigated trees at 304 L per week (lpw) compared with 650 lpw from the year of planting through the third leaf. Similarly, drip irrigation at 182 lpw appears to result in equal tree growth compared with both drip and microsprinkler irrigation at over 600 lpw.
Abdominal aortic aneurysm rupture following cardiopulmonary exercise testing
Authors: Robertson Vaux , Rayt Harjeet , Kirkbride David , Davies Robert
Published: April 2017

A 77‐year‐old male presented with an abdominal aortic aneurysm (AAA). He underwent preoperative cardiopulmonary exercise testing (CPET) to help assess his suitability and fitness for complex major vascular surgery. His aneurysm subsequently ruptured in the post‐test period and he underwent emergency open repair.

CPET is a useful tool in the repertoire of anaesthetic pre‐assessment and helps inform decision‐making in high‐risk surgical patients. However any single test has its limitations and it should not be used in isolation as a reason to deny a patient surgery.

Patients with a diagnosed AAA should not forgo CPET for fear of rupture but should be closely monitored for signs of rapid uncontrolled hypertension ‐ an indication to terminate the test early.
Monitoring Plasma Glucose Concentration from Interstitial Glucose Measurements for Patients at the Intensive Care Unit
Authors: Aguirre-Zapata Estefanía , García-Tirado José Fernando
Published: April 2017

The glucose homeostasis is responsible for regulating the blood glucose concentration around 100 mg / dl. When this physiological mechanism is broken due to the inability of the pancreas to produce insulin, an increase of the blood glucose levels is produced and patients are diagnosed with Diabetes Mellitus. In recent years, some research has directed towards the creation of an artificial pancreas that allows automatically the regulation of glucose levels in blood. However, one of the greatest difficulties in achieving this objective, is that not all internal variables of the mathematical model associated with the controller can be measured directly by physical sensors, either because there are no sensors for all variables, because existing sensors are not commercial, or because they are not viable from the economic point of view. Therefore, it is necessary to use estimation schemes to reconstruct the unknown states by measuring the interstitial glucose , in the case of the glucose-insulin system. However, the delay between plasma glucose and interstitial glucose has a negative effect on the performance of state estimators, so the treatment of this delay is necessary either from the modeling process of the glucose-insulin system or by a modification of the estimation techniques. According to the results it can be inferred that in the scenario at which the concentration of blood glucose is assumed, the estimated values have upper and lower peaks that are unrealistic from a physiological point of view, this due to the negative effect of the delay in measurement. Otherwise, in the scenario where the interstitial glucose concentration is considered as the measured variable, including dynamics of the interstitial glucose, the estimator exhibits better performance and rapid convergence to the real states.
Formulación de Funciones de Costo de Incertidumbre en Pequeñas Centrales Hidroeléctricas dentro de una Microgrid
Authors: Molina Sanchez Ferney Sadid , Pérez Sichacá Sergio Jair , Rivera Rodriguez Sergio Raul
Published: April 2017

El presente artículo propone extender el concepto de costo de incertidumbre en la operación de sistemas de energía que contienen fuentes renovables (solar y eólica) a sistemas de potencia con penetración de pequeñas centrales hidroeléctricas (PCHs). La extensión propuesta se logra obtener conociendo la probabilidad de distribución del caudal donde está la PCH. Para ello, se presenta el desarrollo analítico de los costos de incertidumbre en pequeñas centrales hidroeléctricas, obteniendo la probabilidad de potencia inyectada por la central y desarrollando la formulación matemática de los costos por subestimar y sobreestimar la potencia disponible. Adicionalmente, se presenta la validación de la formulación analítica a través de simulaciones de Monte Carlo, comprobando que en los dos casos (costo de incertidumbre con la formula analítica y valor esperado de la simulación de Monte Carlo) se llega al mismo costo de incertidumbre. Adicionalmente, se presentan los códigos que calculan el costo esperado mediante la formulación analítica obtenida y el costo esperado mediante el valor medio de los costos de la simulación de Monte Carlo.
Producción de Bioetanol a partir de Elodea sp.
Authors: Marulanda López Tatiana , Zapata Osorno Luisa Fernanda , Jaramillo Flórez María Consuelo
Published: April 2017

La dependencia de los países a los combustibles fósiles es cada vez mayor, pero estos no son renovables. Además, el uso de estos combustibles ha aumentado la emisión de gases de efecto invernadero. Colombia debe empezar a buscar otras alternativas que suplan la deficiencia en combustible, y cuya fuente de obtención sea renovable y no comprometa los recursos agrícolas usados como alimentos, tal es el caso de la caña de azúcar. Las plantas invasoras se caracterizan por producir eutrofización de las aguas, ocasionando problemas ambientales y de abastecimiento de agua a las ciudades. El manejo que se hace de esta planta es erradicarla usando diferentes métodos. En este artículo se muestra el aprovechamiento de la planta invasora de cuerpos acuosos, Elodea sp., para la obtención de bioetanol. Después de la hidrólisis de los carbohidratos, la detoxificación, y la fermentación, la planta mostró un alto rendimiento en la producción de bioetanol. Este trabajo es la base para el desarrollo del bioproceso, usando como sustrato el material lignocelulítico, y además, es una alternativa para el manejo de la planta Elodea sp. bomo fuente de energía carburante.
Extreme rainfall statistics in the Marche region, Italy
Authors: Soldini Luciano , Darvini Giovanna
Published: April 2017

A statistical analysis of the rainfalls is carried out for detecting a possible trend in the observed data. The rainfall dataset refers to the historical series collected in the hydrographic basins of the Marche region. On the one hand, the annual maximum daily, hourly and sub-hourly rainfalls have been analysed, on the other hand Climate Change Indices by Expert Team on Climate Change Detection and Indices (ETCCDI) (R1 mm, Rx1day, R20 mm, R95pTOT, PRCPTOT) have been computed to verify an eventual variation of the frequency of the rainfall regime in the Marche region. The time series, selected in the reference period 1951–2013, have been processed by using the non-parametric Mann–Kendall test. The results confirm that most of the series relating to the annual maximum rainfalls do not exhibit any trend. The absence of trend or the presence of negative trend prevail also in the analysis of the ETCCDI indices. The annual average anomalies of the same indices computed with respect to the climatological reference period 1961–1990 are negative since the mid-1980s, but they appear to show an increasing behaviour in the period 2009–2013.
Error features of the hourly GSMaP multi-satellite precipitation estimates over nine major basins of China
Authors: Tan Xianhui , Yong Bin , Ren Liliang
Published: April 2017

As one of the current mainstream satellite precipitation estimates, the Global Satellite Mapping of Precipitation (GSMaP) system of Japan has been developed to produce high-precision and high-resolution global rainfall products by integrating almost all of the available precipitation-related satellite sensors. To quantify the error features of GSMaP estimates and understand their hydrological potentials at short temporal scale, three widely used GSMaP products (GSMaP_NRT, GSMaP_MVK, and GSMaP_Gauge) were comprehensively investigated at 1 hourly and 0.1° × 0.1° resolutions over nine major basins of China. Assessment results show that GSMaP_NRT apparently underestimates the rainfall amounts, while GSMaP_MVK with both forward and backward propagation processes algorithm can effectively capture the most rainfall events and has the lower error and bias. GSMaP_Gauge displays the best error stability and error structure over most basins of China and also exhibits stronger rain-rate dependencies. However, its unexpected positive biases in southeastern basins, which mainly come from the overestimation at lower rain rates, still need to improve further in future developments. We expected the results documented here can both provide the retrieval developers with some valuable references and offer hydrologic users of GSMaP data a better understanding of their error features and potential utilizations for various hydrological applications.
Quantifying multi-source uncertainties in multi-model predictions using the Bayesian model averaging scheme
Authors: Jiang Shanhu , Ren Liliang , Xu Chong-Yu , Liu Shuya , Yuan Fei , Yang Xiaoli
Published: April 2017

This study focuses on a quantitative multi-source uncertainty analysis of multi-model predictions. Three widely used hydrological models, i.e., Xinanjiang (XAJ), hybrid rainfall–runoff (HYB), and HYMOD (HYM), were calibrated by two parameter optimization algorithms, namely, shuffled complex evolution (SCE-UA) method and shuffled complex evolution metropolis (SCEM-UA) method on the Mishui basin, south China. The input uncertainty was quantified by utilizing a normally distributed error multiplier. The ensemble simulation sets calculated from the three models were combined using the Bayesian model averaging (BMA) method. Results indicate the following. (1) Both SCE-UA and SCEM-UA resulted in good and comparable streamflow simulations. Specifically, the SCEM-UA implied parameter uncertainty and provided the posterior distribution of the parameters. (2) In terms of the precipitation input uncertainty, precision of streamflow simulations did not improve remarkably. (3) The BMA combination not only improved the precision of streamflow prediction, but also quantified the uncertainty bounds of the simulation. (4) The prediction interval calculated using the SCEM-UA-based BMA combination approach appears superior to that calculated using the SCE-UA-based BMA combination for both high flows and low flows. Results suggest that the comprehensive uncertainty analysis by using the SCEM-UA algorithm and BMA method is superior for streamflow predictions and flood forecasting.