bluuebunny/crossref_metadata_2025 huggingface dataset:
Clustering-Based Optimal Perforation Design Using Well Logs
Authors: Popa A. , Hao M. , Cassidy S. D. , Cover A. , Shepherd D. , Jikich S.
Published: October 2015

In an effort to better understand the well performance in one of the Chevron's assets in San Joaquin Valley, a study was conducted to evaluate the perforation strategies and capture best practices. Well completion through perforation is typically performed using bare essential technology such as wireline logs and perforation guns. For basic reservoir formations simple rules-of-thumb are used for perforation spacing and interval lengths. These are rarely validated by other methods, such as production logging and micro-seismic monitoring. For more challenging lithology, a more appropriate approach would be to place perforation clusters in target formations with similar properties.

The research paper presents an efficient use of fuzzy clustering technology for identification of optimum perforation strategy in a challenging waterflood diatomite reservoir. The methodology was applied on all newly drilled wells in the reservoir (within the last two years) and found that this new approach improved our understanding over previous practices, not only by designing optimum perforations but also an increased production was observed.

Cluster analysis is the task of grouping a set of objects in such a way that objects in the same group (called a cluster) are more similar to each other (in some sense or another) than to those in other clusters. There are two commonly used types of clustering methods: hard and fuzzy clustering. In hard clustering, data is divided into distinct clusters, where each data element belongs to exactly one cluster. In fuzzy clustering, data elements can belong to more than one cluster, and associated with each element is a set of membership levels.

The fuzzy clustering algorithm, also known as Fuzzy C-Mean (FCM) algorithm, was applied to log data of wells from different areas of a reservoir. Based on the clustering results, the workflow then identified whether the perforation was performed on "good" regions (sand) or on "bad" regions (shale bedding). This information allowed the evaluation of perforation jobs executed and allowed capturing best practices and design changes for future well completions.

The case study presents a simple, yet efficient workflow to extract additional information from logs and improve completion strategies and perforation design. The methodology is flexible and can be applied to any well where complex lithology creates a challenge in defining the optimum perforation intervals.
Impact of Nanoscale Pore Confinement on Estimation of Gas Resources and Gas/Condensate Behavior in Shale Reservoirs
Authors: Allawe E. M. , Stockdale A. P. , Aminiaa K. , Ameri S.
Published: October 2015

The reservoir fluid properties exhibit significant deviation from their bulk properties under confinement in nanopores. As a result, storage capacity and recovery can be impacted in the shale reservoir due to nanoscale pore structure. It is therefore critical to investigate the impact of pore confinement to accurately estimate the gas resources and the phase behavior in the shale reservoirs. In this study, the shift in critical properties of the typical Marcellus Shale gas confined in different size nanopores were determined. The adjusted fluid properties was then used to estimate the gas deviation factor for dry gas and to predict the phase behavior of gas/condensate. The gas/condensate fluid model was then used in a compositional reservoir simulator in order to estimate the liquid recovery from a Marcellus Shale gas/condensate reservoir developed by hydraulically fractured horizontal well.

The results indicate that the gas storage capacity of the shale is altered by the pore confinement. The degree of the fluid properties alteration by pore proximity in the shale depends on the composition of the gas mixture and the size of the nanopores. Therefore to accurately estimate the gas resources in the shale reservoirs, it is necessary to incorporate the alteration of the gas deviation factor by pore proximity. In gas/condensate shale reservoirs the fluid confinement could have either positive or negative impact on the liquid recovery depending on the pore size. The results of the investigation can provide an insight relative to production optimization and economic recovery of gas/condensate reservoirs in the unconventional resources.
Evolving Air Regulations Are Causing Inconsistencies Across the Marcellus Shale Basin
Authors: Seguljic Thomas S.
Published: October 2015

Twenty years ago geologists involved in the Appalachian Basin's oil and gas industry knew about the Devonian black shale called the Marcellus, its black color made it easy to identify. However, at the time, very few of these geologists were excited about the Marcellus Shale as a major source of natural gas. Wells drilled into the formation produced some gas but rarely in commercially viable volumes. Few if any in the natural gas industry suspected that the Marcellus would soon be a major contributor to the natural gas supply of the United States – large enough to be called a "super giant" gas field. (King, 2015).
Efficient Semi-Analytical Engine for Performance Prediction of Unconventional Reservoirs
Authors: Olalotiti-Lawal Feyi , Friedel Torsten
Published: October 2015

Reliable and fast prediction of fractured well performance is vital for asset evaluation and prudent field development decision making in unconventional, low permeability oil and gas reservoirs. Simple low cost techniques such as decline curve analysis are ill suited of properly accounting for extended transient flow regimes. Numerical simulation techniques on the other hand are unrivaled in capturing geological details and high accuracy in fluid flow description. However, they suffer from high computational expense and often too little relevant data is available. Our objective is to develop an efficient semi-analytical solution that combines the advantages of speed and accuracy from both techniques for forecasts on single well, pad and even field level.

Contrary to conventional oil and gas reservoirs, the tight reservoir characteristics allow for the application of analytical solutions to predict the behavior of fractured wells. The depth of investigation is small with spatial property variations having limited influence considering the large local pressure gradients. Fluid flow is mainly of transient nature and less dominated by multi-phase flow effects within the reservoir. Moreover, the typical configuration of an individual well with multiple fracture stage, entire pads with multiple wells or even entire assets allow the application of the superposition in space, providing a cheap means for accurate solution for multi-well problems.

This paper presents a transient semi-analytical model based on a tri-linear formulation. It accurately captures fluid flow to a single or multiple fractured wells over the entire life cycle of production, from early linear flow to pseudo-steady boundary driven flow. It is applicable to oil or gas reservoirs with permeabilities ranging from nano-Darcies to approximately one milli-Darcy. It is capable of handling both the vertical and horizontal well type, with either single or multiple fracture stages respectively. Well-bore, stage and pad configurations can be freely parametrized. A tubing head pressure boundary condition is incorporated to model production from those wells more realistically. For shale type reservoirs, a desorption process is incorporated.

The model is particularly suitable for quantitative evaluation of field development alternatives involving a large number of fractured wells. The accuracy compared to a high resolution numerical simulation model generally exceeds 90% with a computation speedup factor in the order of one hundred or more. Besides conventional benchmarking with a numerical reservoir simulator, actual field production data from the Marcellus and Eagleford shale wells shows the utility of the new solution. Being both fast and accurate, the technique presented in this paper is ideal for supporting high quality, cost efficient decision making which is crucial in the current low oil price environment.
Production Analysis Using Rate Transient Analysis
Authors: Belyadi Hoss , Yuyi Silumesii , Junca-Laplace Jean-Philippe
Published: October 2015

Shale reservoirs have low permeability, high fluid efficiency, and low fluid leak-off making these types of reservoirs ideal for hydraulic fracturing. One of the biggest challenges in analyzing unconventional shale reservoirs is that their flow regimes stay in transient flow for a very long period of time. This aspect of unconventional shale reservoirs makes it very challenging to estimate recoverable resources along with reservoir properties such as fracture half length, permeability, drainage area, and fracture conductivity. Conventional decline curve analysis assumes constant flowing bottom-hole pressure, drainage area, permeability, skin, and existence of boundary dominated flow. Most of these assumptions are no longer valid in unconventional reservoirs. Therefore, it is crucial that not only rate, but also pressure and other reservoir parameters are taken into account to properly evaluate unconventional wells and determine the true flow capacity of their reservoir in linear transient flow.

This study uses rate transient analysis (RTA) which plots pseudo normalized pressure versus material balance square root of time to estimate the productivity of Marcellus Shale wells. Our dataset is limited to a restricted area located in Greene and Washington Counties, Pennsylvania, with similar reservoir properties such as porosity, water saturation, pressure, and temperature. With limited variation in reservoir properties, the slope of the superposition plot used to calculate AK becomes a good metric for well productivity. The y-intercept from the same plot indicates the completions effectiveness of the well. The slope of the line for a well with zero completions damage intersects the origin. Any completions damage (skin damage) caused by poor completions designs or unfavorable reservoir properties will have a higher y-intercept in relation to the origin in the superposition plot. After performing this analysis on operated wells in the study area located in Washington and Greene Counties, the wells with the most successful completions methods were identified. This knowledge can then be applied for future wells in the same area for optimum production enhancements.
Impact of Drilling With Oil Based Mud on Well Control in Horizontal Shale Gas Wells
Authors: Elshehabi Tawfik , Bilgesu Ilkin
Published: October 2015

Objective of this study is to shed light to critical well control parameters of horizontal shale gas wells drilled with oil based muds (OBM). This study utilizes an interactive well control simulator to re-evaluate the kick control procedures in water based mud (WBM) and verify its application to oil based mud. Due to gas solubility in OBM a real time drilling and hydraulics data analysis is essential to minimize kick volumes. Therefore, early kick detection and surface warning signs are critical to minimize the influx size and reduce wellbore pressures. Moreover, the impacts of water-to-oil ratio, gas solubility, kick size, influx type and circulation rates on well control are investigated. OBM kick control process in horizontal wells creates additional challenges since the surface pressure and volume are not representative of the bottom-hole conditions. In unconventional shale gas reservoirs, oil and synthetic based drilling fluids are very common. Drilling cost, log interpretation, and environmental impacts are the main drawbacks of OBM. However, wellbore stability, reduction in torque and drag, stability of mud properties at higher temperatures and better drilling performance are the main advantages of OBM. Preliminary results show that dissolved gas in oil is liberated at the bubble point pressure and complicates surface kick handling procedures. Choke adjustment is hard due to the unexpected high volume of gases released and the delay time of choke response. Early detection is a key factor in minimizing the influx size and properly controls the casing shoe and choke pressures. Based on 110 hours of real time interactive simulation, influence of gas solubility on well control in OBM is presented to improve rig and personnel safety and reduce the blowout associated risks.
Production Decline Models: A Comparison Study
Authors: Ali Tariq A. , Sheng James J.
Published: October 2015

Erroneous reserve estimates associated with improper application of Arp's relations has led to the development of alternative rate-time models based on empirical considerations. These models can equally provide good fits for only limited duration production data, but they yield significantly different 30-year-estimated ultimate recovery (EUR).

In our previous work, we extensively demonstrated the reliability of cumulative-production model to analyze the production performance of fractured dominated tight and shale reservoirs.

In this paper, a number of real field examples are used to generate 30-year-EUR estimates using different rate-time models as well as a production-decline model.

Results show that some of rate-time models overestimate EUR with more than 150% compared with the cumulative production-decline model which yields correct estimates in most of the cases.
Experimental Investigation of Geomechanical Impacts on Organic-Rich Shales Matrix-Fracture Characterization
Authors: Zamirian Mehrdad , Aminian Kashy , Ameri Samuel
Published: October 2015

During hydraulic fracturing process, the formation undergoes significant changes in the net stress as a result of the fluid injection and retrieval. These stress changes impact the formation petrophysical properties including permeability, porosity, and the compressibility. In this experimental study, the impact of geomechanical changes on shales petrophysical properties is investigated using a laboratory set-up that was designed and assembled for fast and robust shale core plug porosity and permeability measurements under steady-state conditions. This laboratory set-up is capable of accurately measuring shale core plug ultra-low permeability and porosity because it has a resolution of one millionth standard cubic centimeters per second for gas flow rate and one hundredth cubic centimeters for pore volume measurement. The laboratory set-up allows measurements to be performed under isothermal conditions by automated temperature control. The application of the confining pressure on the shale core plug allows permeability and porosity to be measured under a wide range of net stress.

A sequential set of experiments were performed in this study. During the first set of experiments, the permeability of the core plug was measured by increasing the net stress from 500 psia to 7,900 psia followed by decreasing net stress from 7,900 psia to the initial net stress condition. The next three sets of experiments repeated the same steps as the first set on the same core plug. However, during the third set only the porosity, and during the fourth set only permeability was measured.

The measured porosity and permeability values from the experiments clearly exhibited hysteresis with the net stress changes. The hysteresis was more pronounced for permeability than it was for porosity. Since the permeability changes were non-linear with respect to net stress changes, Walsh method was used to estimate the fracture closure pressure. The results indicate that sequential net stress changes can cause a reduction in fracture closure pressure. This reduction however tends to diminish with increasing number of sequential stress changes. Finally, comparing the porosity and permeability measurements revealed two distinctive behavioral changes for both porosity and permeability that can be contributed to the natural fracture and matrix properties.
Utilizing Cement Bond Logs to Evaluate Wellbore Integrity for Local and Regional Scales
Authors: Haagsma A. , Burchwell A. , Sminchak J. , Gerst J. , Moody M.
Published: October 2015

Wellbore integrity is a fundamental aspect of site characterization for storage in areas with existing or abandoned oil and gas wells. The condition of well cement and casing structures determine if a well can sustain optimal hydrostatic pressures and prevent leakage. This is a necessary but underappreciated aspect of assessing potential reservoirs when optimal and sustainable pressure conditions are critical for success. Cement bond logs (CBLs), a tool not generally used efficiently, can represent the cement quality around a wellbore and be used to identify intervals of poor cement integrity. A standardized CBL evaluation tool was created to remove inconsistencies in interpretations and used to evaluate 394 CBLs in Michigan and 306 CBLs in Ohio.

700 CBLs were analyzed for six site specific study areas and reviewed regionally across Michigan and Ohio to identify any trends in cement quality and highlight possible fluid migration pathways through wellbores with poor cement integrity. The CBL evaluation tool uses a quantitative bond index method to assign percent bond to wireline log readings based on user defined conditions. Once analyzed, the tool outputs a descriptive statistical dataset. Industry standards were used to categorize wells based on cement quality. Correlations between cement quality and the year and season the well was completed, well depth, cement column thickness, and formations cemented over were explored using basic statistics and graphing methods. As well, a standardized assessment of such a variety of wells and cement conditions allows for the incorporation of these wellbores into subsurface models to identify possible zones of weakness for ideal pressure conditions.

There were no strong correlations on the regional scale between cement quality and year/season well was completed, depth of the well, and cement column thickness. The tool was very useful in providing red flags in the assessment of a site specific study area and in the evaluation of potential confining layers. Within a study area it was easy to identify wells with poor cement quality and determine if the wells posed a risk to a potential storage site. High risk areas for potential confining layers were also mapped and could be used as a guide to determine areas of poor cement bond within a specific formation.
Understanding the Impact of Rock Properties and Completion Parameters on Estimated Ultimate Recovery in Shale
Authors: Javadi Faegheh , Mohaghegh Shahab D.
Published: October 2015

Estimating ultimate recovery (EUR) in shale is a function of rock properties, well, and completion design parameters. The variation associated with these parameters are in source of uncertainty. In this paper the combined decline curve (CDC) approach is used to estimate the EUR of shale wells. CDC is a conservative approach that combines hyperbolic (in early time) and exponential (in later time) declines for production analysis. The major objective of this work is to condition the results of the CDC-EUR of shale wells to rock properties, well characteristics, and completion design parameters in a given shale asset. As the first step CDC-EUR is estimated. In the second step data-driven analytics using artificial neural networks is employed to condition the CDC-EUR to rock properties, well characteristics, and completion design parameters. Then, artificial Intelligence techniques are used in order to extract the nonlinear relationship between well productivity and reservoir characteristics and completion parameters. In this study 168 wells from Marcellus shale asset are examined.

The major rock properties that are studied are porosity, total organic content, net thickness, and water saturation. Moreover, the effect of several design parameters, such as well inclination and azimuth, stimulated lateral length, stage length, number of clusters per stage, and amount of fluid and proppant are studied. A data driven model is developed using AI techniques. Results show that the model is able to find the relationship between the input parameters and EUR. Thus, this model will help petroleum professionals to have a better understanding of the effect of rock properties and design parameters on the future production from shale wells.
Economic Evaluation of Marcellus and Utica Under the Effects of Dynamic Market and Development Conditions
Authors: Ozkan S. , Duman R.
Published: October 2015

The Marcellus and Utica are among the most talked about natural gas plays in the country. In this paper their productivity and economics are examined, along with a production forecast. The type curves for natural gas and oil for different production areas within the Marcellus and Utica are compiled from well-level production data to gauge productivity differences between different parts of the plays. A drilling schedule is applied to the type curves to arrive at a production forecast for the various regions. Using the type curves and processing plant data, a natural gas liquids production forecast is provided as well. The breakeven natural gas prices and internal rates of return for the various production areas are calculated using a discounted cash flow model. These metrics are compared to other plays across the US to understand the competitiveness of the Marcellus and Utica, particularly in natural gas production growth, going forward. The Marcellus already boasts the best natural gas play economics in the country and will continue to be the cheapest source of natural gas production outside of natural gas volumes produced in association with oil-directed drilling. The Utica has great production potential, as can be seen in the impressive initial production rates already observed in certain windows of the Utica. However, the high drilling and completion costs and various operational problems need to be overcome if the play is to mature into the development phase. Both the Marcellus and the Utica will continue to see investment. The Marcellus will attract capital due to its already prolific economics, and the Utica will attract capital due to the high productivity potential that could be unlocked by marching up the learning curve.
Study on Particles Wetted by the Calcium-Based Slurries and the Slurries
Viscosity with the Wetting Agents
Authors: Hao Xiaowen , Zhang Zhijun , Liu Ran
Published: October 2015

Chemical agglomeration can reduce the particulates (including PM2.5) concentration emitted from fly ash particulates
and the wet flue gas desulfurization (WFGD) system. However, the calcium-based slurries affect the regulation
of agglomeration compared to water, in particular, the wettability of the particulates and the viscosity of the calciumbased
slurry. The wettability and the viscosity are the important factors affecting agglomeration, conversely. This manuscript
studied the two factors affecting the calcium-based slurries. The sessile drop method was used to measure the contact
angle. Four kinds of calcium-based slurries (CaCO3, CaSO3, CaSO4, Ca(OH)2) respectively were mixed with five
kinds of wetting agents’ wet particles, and the wetting regulation was studied. The viscometer was used to measure the
viscosity of the calcium-based slurry with the wetting agents, and the variation of the viscosity was analyzed as well. The
results showed that the smaller the particle size was, the more it is difficult to be wet, and the wetting agents could enhance
the wettability greatly, but the effect was related to the properties of the calcium-based material and the wetting
agents. There were variable viscosities of different calcium-based slurries after adding the wetting agents. Overall, the
Compound No. 3 had the optimal qualities in improving particle wettability and maintaining the calcium-based slurry with
a high viscosity. Therefore, the Compound No. 3 is considered the optimal in facilitating chemical agglomeration.
Shot Performance Influence Factors Correlation Degree Analysis Based on
Genetic Algorithms
Authors: Yang Lei
Published: October 2015

The paper first applies Newton mechanical and physical knowledge to establish shot throwing process mathematical
model, calculates throwing performance is related to α, h, t0, v0 these five factors; the next, it adopts genetic
algorithms to solve optimal throwing performance and these five factors best parameters, from which optimal throwing
performance is 21.78m; finally it adopts grey relational degree algorithms and analyzes five influence factorsf primary
and secondary relation is α, h, t0, v0 , which provides scientific evidence for making scientific training plans, during
training, coaches and athletes should pay attention to foster strengths and circumvent weakness, give their own advantages
into full play so that can get more ideal results.
Test Analysis on the Dynamic Performance of Frozen Silty Clay
Authors: Bin Zheng , Yang Xu , Shanshan Zheng , Shuying Qu
Published: October 2015

Currently, over half of China’s trunk railways are located in permafrost regions. But to tackle the railway subgrade
disease has always been the difficulty in the railway construction there. The influence that the dynamics performance
of frozen silty clay has on permafrost subgrade is an important component in the researches towards permafrost subgrade.
In this paper, the dynamics performance of frozen silty clay in permafrost regions is studied based on the indoor dynamic
triaxial test at a low temperature, and at the same time, by studying the influence that several factors like cyclic matrix,
confining pressure, temperature and frequency have on relevant dynamics parameters, basis can be provided for the transformation
and settlement mechanism of permafrost subgrade as well as for the analysis towards the permafrost’s influence
on vibration response under train load, and it offers much reference value to permafrost subgrade’s design.
Study of the Fault Diagnosis Model of High Pressure Roller Mill Gearbox
Lubrication System
Authors: Wang Xijuan , Zhang Lei , Feng Jingxiao , Zhou Wei , Gao Haiyan
Published: October 2015

The fault phenomenon of high pressure roller mill gearbox lubrication system is not easy to be find in many cases,
the fault of system is easy to be ignored, and it is more difficult to judge with the traditional method. For this reason, the fault
diagnosis model of the particle swarm neural network has been established by using actual sample data, determining the
cause of fault through the actual monitoring data. The practice has proved that it has better prediction effect.
Estimation of Fatigue Life of Long-Span Bridge by Considering Vehicle-
Bridge Coupled Vibration
Authors: Jiao Ling
Published: October 2015

To estimate the fatigue life of long-span steel bridge more accurately, this paper proposes a method for
estimating the fatigue life of long-span bridges by considering vehicle-bridge coupled vibration. Firstly, the universal
equation of vehicle-bridge vibration is derived based on triaxial standard multi-scale model of fatigue vehicle and bridge,
and relevant program for vehicle-bridge coupled vibration is programmed. Secondly, a method for estimating the fatigue
life of long-span steel bridge is proposed based on fracture mechanics theories, and the analysis process is expounded in
details. Finally, the method for estimating fatigue life proposed in this paper is verified by taking a double pylon cablestayed
bridge with orthotropic steel bridge deck slab as an example.
Improving Vehicle Detection Accuracy Based on Vehicle Shadow and
Superposition Elimination
Authors: Zhu Hongjin , Fan Honghui , Ye Feiyue , Zhao Xiaorong
Published: October 2015

Vehicle shadow and superposition have a great influence on the accuracy of vehicles detection in traffic video.
Many background models have been proposed and improved to deal with detection moving object. This paper presented a
method which improves Gaussian mixture model to get adaptive background. The HSV color space was used to eliminate
vehicle shadow, it was based on a computational colour space that makes use of our shadow model. Vehicle superposition
elimination was discussed based on vehicle contour dilation and erosion method. Experiments were performed to verify
that the proposed technique is effective for vehicle detection based traffic surveillance systems. Detection results showed
that our approach was robust to widely different background and illuminations.
The Effectiveness of Corticosteroid Injection for De Quervain’s Stenosing Tenosynovitis (DQST): A Systematic Review and Meta-Analysis
Authors: Rowland Patrick , Phelan Nigel , Gardiner Sean , Linton Kenneth N , Galvin Rose
Published: October 2015

De Quervain’s stenosing tenosynovitis (DQST) treatments include corticosteroid injection around the tendon sheath; however there is some ambiguity concerning the efficacy of this treatment. The aim of this systematic review and meta-analysis is to examine the totality of evidence relating to the use of corticosteroid injection in DQST when compared to placebo or other active treatments. A systematic literature search was conducted in July 2014. Only randomized control trials (RCTs) were included.Outcome measures included impairment, activity limitation and participation restriction.Five RCTs were identified with165 patients, 88 in the treatment group and 77 in the control group.

Patients who received corticosteroid injection (n=142) had a higher rate of resolution of symptoms [RR 2.59, 95% CI: 1.25 to 5.37, p=0.05,I2=62%]. This group reported greater pain relief as assessed by Visual Analogue Scale (VAS) at first assessment [mean difference -2.51, 95% CI: -3.11 to -1.90, p=0.0003,I2=65%] and demonstrated a statistically significant improvement in function (n=78) as measured by the DASH score and Dutch AIMS-HFF score [SMD -0.83, 95% CI: -1.54 to -0.12, p=0.02,I2=48]. This review confirms that corticosteroid injection results in a statistically significant increase in resolution of symptoms, pain relief and increased function in the treatment of DQST.
Acute Osteochondral Fractures in the Lower Extremities - Approach to Identification and Treatment
Authors: Pedersen M.E , DaCambra M.P , Jibri Z , Dhillon S , Jen H , Jomha N.M
Published: October 2015

Chondral and osteochondral fractures of the lower extremities are important injuries because they can cause pain and dysfunction and often lead to osteoarthritis. These injuries can be misdiagnosed initially which may impact on the healing potential and result in poor long-term outcome. This comprehensive review focuses on current pitfalls in diagnosing acute osteochondral lesions, potential investigative techniques to minimize diagnostic errors as well as surgical treatment options. Acute osteochondral fractures are frequently missed and can be identified more accurately with specific imaging techniques. A number of different methods can be used to fix these fractures but attention to early diagnosis is required to limit progression to osteoarthritis. These fractures are common with joint injuries and early diagnosis and treatment should lead to improved long term outcomes.
A Novel Minimally Invasive Technique for Treatment of Unicameral Bone Cysts
Authors: Zaghloul Ahmed , Haddad Behrooz , Khan Wasim , Grimes Lisa , Tucker Keith
Published: October 2015

Management of unicameral bone cysts (UBC) remain controversial. These cysts seldom heal spontaneously or even after pathological fracture. Sometimes these cysts can be very large and incredibly troublesome to the patient. Various treatments exist with variable success rates. We present our experience of treating these lesions by continuous drainage. Over a seven year period, six patients with unicameral bone cysts were treated by inserting a modified drain into the wall of the cyst. The aim of surgery was to place the drain in a dependent area of the cyst, through the cortex allowing for continuous drainage. This was achieved through a small incision under radiographic control. A cement restrictor (usually used for femoral canal plugging during total hip replacements) was modified and inserted to prevent closure of the drain site. A redivac drain was passed through the plug into the cyst. The drain was left in place for a week to establish an epithelialized pathway which hopefully would remain patent, into the subcutaneous tissues, after the drain had been removed. There were four males and two females in the group and the age range was 6 -12 years. Four of the lesions were in the upper humerus, one in the proximal femur and the other one in the proximal tibia. Healing was rated according to the modified Neer classification. Grade 1 (healed) and Grade 2 (healed with defect) was defined as excellent outcome. Persistent /Recurrent cysts (Grade 3 and 4) were noted as unsatisfactory. Five cases were completely healed. Only one had a further fracture and there were no recurrent fractures. All the patients reported complete comfort and they all were able to re-engage in recreational activities without restriction. We think that reducing the intra-medullary pressure in these lesions will lead to healing. We report a safe and minimally invasive technique for the management of UBC.
Bilateral Simultaneous Total Knee Arthroplasty: A Patient-Matched Retrospective Observational Study
Authors: Haddad Behrooz , Khan Wasim , Mehta Vikas , Mbubaegbu Chima , Qamar Arshad
Published: October 2015

Bilateral total knee arthroplasty can be performed either as a staged or simultaneous procedure. We conducted a retrospective comparative study to compare the need for transfusion, the length of procedure, the length of stay, and complications of bilateral simultaneous knee arthroplasty with those of unilateral knee arthroplasty. Sixty-nine patients who underwent bilateral simultaneous knee arthroplasty procedures were compared with a matched control group of 69 patients who underwent unilateral knee arthroplasty. Receiver Operating Characteristic (ROC) curve was used to determine optimum cut-off values. Both groups of patients had a similar age and gender distribution, preoperative haemoglobin and ASA scores. Cumulative transfusion episodes were lower in the bilateral group than twice that of the unilateral group. In multivariate analysis the preoperative haemoglobin level and bilateral procedures were independent factors predicting the need for transfusion. The average length of procedure and length of hospital stay in the bilateral group was less than twice than that of the unilateral group. Advanced age and bilateral procedures were independent predictors of prolonged length of stay. A haemoglobin level of 12.5 g/dL and age of 70 were most suitable cut-off points to predict need for transfusion and occurrence of medical complications respectively. We conclude that bilateral simultaneous knee arthroplasties are safe and cost effective in appropriately selected patients. We recommend avoiding bilateral simultaneous procedures in patients over the age of 70 years and with significant comorbidities.
The Association Between Primary Open Angle Glaucoma and Clustered Components of Metabolic Syndrome
Authors: Rasoulinejad Seyed Ahmad , Kasiri Ali , Montazeri Mahdi , Rashidi Negin , Montazeri Maryam , Montazeri Mohammad , Hedayati Hesam
Published: October 2015

Purpose :

There is conflicting evidence whether components of metabolic syndrome (MetS) increase or decrease the risk of primary open-angle glaucoma (POAG). The aim of the present study was to determine the association between metabolic syndrome and primary open-angle glaucoma.

Methods :

A total of 200 participants comprising 100 controls and 100 patients with POAG documented by clinical tests and examined by an experienced ophthalmologist using standard ophthalmologic equipment were included in the study. MetS was defined and based on ATP III criteria and POAG was defined by the criteria of the International Society of Geographic and Epidemiological Ophthalmology (ISGEO). The data were entered into the SPSS software and analyzed.

Results :

The prevalence of MetS in the glaucoma group was 53% in comparison to 38% in the control group (p=0.037). MetS was associated with an increased odds ratio for an IOP higher than 21 mmHg (OR: 1.72; 95% CI 1.03-2.79; p=0.034). The mean IOP was 24.91±4.29 mmHg in the patients without MetS, and 27.23±4.81 mmHg in those with MetS (p=0.027). The mean values of CCT were 603.64±63.16 µm in MetS patients and 579.27±72.87 µm in controls (p=0.018).

Conclusion :

Data showed an increased prevalence of components of metabolic syndrome in patients with glaucoma. The mechanisms underlying these associations need to be established in future studies. Our results support the recommendation that patients with metabolic syndrome undergo regular ophthalmological exams to monitor for the onset or progression of glaucoma.
The Synergistic Scheduling Optimization Model for Wind Power and Thermal Power with Energy Storage System Under the Carbon Emission Trade
Authors: Hai-Bo Liu , He Xin , Hongliang Wu , Bao-Rong Zhou , Nan Dong , Ge Pan
Published: October 2015

In order to alleviate the effect of randomness and intermittent of wind power output on safe and stable
operation of the power grid and improve system consumptive wind power capacity, the paper introduce carbon emissions
trading and energy storage systems to construct the collaborative scheduling optimization model of wind power and
energy storage system based on the energy generation scheduling optimization model of wind power and thermal power.
Then, 10 thermal power and 2800MW wind farms constitute simulation systems to analyze the impact of carbon trading
and energy storage systems on system wind power consumptive capacity. Numerical example shows: The introduction of
carbon trading can increase wind power capacity and reduce coal consumption systems; the introduction of the energy
storage system can gentle wind power output, suppress power fluctuations; While, system optimization results achieve the
best when carbon trading and energy storage systems are introduced at the same time.
The Research of Measuring Approach and Energy Efficiency for Hadoop
Periodic Jobs
Authors: Junyang Yu , Zhigang Hu , Yuanyuan Han
Published: October 2015

Current consumption of cloud computing has attracted more and more attention of scholars. The research on
Hadoop as a cloud platform and its energy consumption has also received considerable attention from scholars. This paper
presents a method to measure the energy consumption of jobs that run on Hadoop, and this method is used to measure the
effectiveness of the implementation of periodic tasks on the platform of Hadoop. Combining with the current mainstream
of energy estimate formula to conduct further analysis, this paper has reached a conclusion as how to reduce energy consumption
of Hadoop by adjusting the split size or using appropriate size of workers (servers). Finally, experiments show
the effectiveness of these methods as being energy-saving strategies and verify the feasibility of the methods for the
measurement of periodic tasks at the same time.
Capability-oriented architectural analysis method based on fuzzy description logic
Authors: Tingting Zhang , Xiaoming Liu , Zhixue Wang , Qingchao Dong
Published: October 2015

A number of problems may arise from architectural requirements modeling,
including alignment of it with business strategy, model integration and
handling the uncertain and vague information. The paper introduces a method
for modeling architectural requirements in a way of ontology-based and
capability-oriented requirements elicitation. The requirements can be modeled
within a three-layer framework. The Capability Meta-concept Framework is
provided at the top level. The domain experts can capture the domain
knowledge within the framework, forming the domain ontology at the second
level. The domain concepts can be used for extending the UML to produce a
domain-specific modeling language. A fuzzy UML is introduced to model the
vague and uncertain features of the capability requirements. An algorithm is
provided to transform the fuzzy UML models into the fuzzy Description Logics
ontology for model verification. A case study is given to demonstrate the
applicability of the method.
Comparison of Oxidant-Antioxidant Status in Patients with Vitiligo and Healthy Population
Authors: Agrawal S , Kumar A , Dhali TK , Majhi SK
Published: October 2015

Background Vitiligo is a well-recognized pigmentary disorder of the skin and /or mucous membrane characterized by circumscribed ivory or chalky white macules devoid of identifiable melanocytes. The pathogenesis of vitiligo is complex and still not well understood. According to autocytotoxic hypothesis, oxidative stress has been suggested to be the initial pathogenic event in melanocyte degeneration. The role of free radicals and oxidative damage in the pathophysiology of vitiligo has been documented in recent studies.Objective To evaluate the role of oxidative stress in patients with vitiligo and of healthy controls by measuring levels of the oxidant malondialdehyde (MDA) and antioxidants vitamin C and vitamin E in serum and catalase (CAT) in erythrocytes.Method A total of 80 clinically diagnosed cases of vitiligo and 80 control subjects were included in the study to assess the activity of MDA, vitamin C and vitamin E in serum and CAT in erythrocytes of patients and controls by using the spectrophotometric assay.Result There was statistically significant increase in the levels of MDA in patients with vitiligo compared to the control group (p<0.001). No significant difference was found in the levels of vitamin C (p=0.411) and vitamin E (p=0.771) between the patients with vitiligo and control group. The levels of CAT in the vitiligo patients were found to be significantly lower than those of controls (p<0.001).Conclusion Increased oxidative stress and decreased catalase have been observed in vitiligo patients and the data suggesting that the free radicals may be involved in the destruction of melanocytes or dysregulation of melanogenesis.Kathmandu University Medical Journal Vol.12(2) 2014: 132-136
Faster extubation time with more stable hemodynamics during extubation and shorter total surgical suite time after propofol-based total intravenous anesthesia compared with desflurane anesthesia in lengthy lumbar spine surgery
Authors: Lu Chueng-He , Wu Zhi-Fu , Lin Bo-Feng , Lee Meei-Shyuan , Lin Chin , Huang Yuan-Shiou , Huang Yi-Hsuan
Published: October 2015

OBJECT

Anesthesia techniques can contribute to the reduction of anesthesia-controlled time and may therefore improve operating room efficiency. However, little is known about the difference in anesthesia-controlled time between propofol-based total intravenous anesthesia (TIVA) and desflurane (DES) anesthesia techniques for prolonged lumbar spine surgery under general anesthesia.

METHODS

A retrospective analysis was conducted using hospital databases to compare the anesthesia-controlled time of lengthy (surgical time > 180 minutes) lumbar spine surgery in patients receiving either TIVA via target-controlled infusion (TCI) with propofol/fentanyl or DES/fentanyl-based anesthesia, between January 2009 and December 2011. A variety of time intervals (surgical time, anesthesia time, extubation time, time in the operating room, postanesthesia care unit [PACU] length of stay, and total surgical suite time) comprising perioperative hemodynamic variables were compared between the 2 anesthesia techniques.

RESULTS

Data from 581 patients were included in the analysis; 307 patients received TIVA and 274 received DES anesthesia. The extubation time was faster (12.4 ± 5.3 vs 7.0 ± 4.5 minutes, p < 0.001), and the time in operating room and total surgical suite time was shorter in the TIVA group than in the DES group (326.5 ± 57.2 vs 338.4 ± 69.4 minutes, p = 0.025; and 402.6 ± 60.2 vs 414.4 ± 71.7 minutes, p = 0.033, respectively). However, there was no statistically significant difference in PACU length of stay between the groups. Heart rate and mean arterial blood pressure were more stable during extubation in the TIVA group than in the DES group.

CONCLUSIONS

Utilization of TIVA reduced the mean time to extubation and total surgical suite time by 5.4 minutes and 11.8 minutes, respectively, and produced more stable hemodynamics during extubation compared with the use of DES anesthesia in lengthy lumbar spine surgery.
Thoracic spinal subdural hematoma complicating anterior cervical discectomy and fusion: case report
Authors: Protzman Nicole M. , Kapun Jennifer , Wagener Christopher
Published: October 2015

A spinal subdural hematoma is a rare clinical entity with considerable consequences without prompt diagnosis and treatment. Throughout the literature, there are limited accounts of spinal subdural hematoma formation following spinal surgery. This report is the first to describe the formation of a spinal subdural hematoma in the thoracic spine following surgery at the cervical level. A 53-year-old woman developed significant paraparesis several hours after anterior cervical discectomy and fusion of C5–6. Expeditious return to operating room for anterior cervical revision decompression was performed, and the epidural hematoma was evacuated without difficulty. Postoperative imaging demonstrated a subdural hematoma confined to the thoracic level, and the patient was returned to the operating room for a third surgical procedure. Decompression of T1–3, with evacuation of the subdural hematoma was performed. Postprocedure, the patient’s sensory and motor deficits were restored, and, with rehabilitation, the patient gained functional mobility. Spinal subdural hematomas should be considered as a rare but potential complication of cervical discectomy and fusion. With early diagnosis and treatment, favorable outcomes may be achieved.