bluuebunny/crossref_metadata_2025 huggingface dataset:
Take or Pay Obligation in Long Term Gas Contract: Risk Mitigation Options for Off-taker
Authors: Green Ovunda , Iledare Omowumi
Published: July 2015

Traditionally, the gas industry is characterised by long-term take or pay (TOP) clause. It is the basis upon which gas is brought out of the ground. However, the absence of an established international gas market and the capital intensive nature of gas infrastructures quite often do discourage investors from committing funds to gas projects. Thus, a well-structured TOP mechanism serves as a guarantor for investors for the recovery of capital investment and favourable return on investment. TOP obligation, therefore, commits the buyer to take or pay for certain minimum volume of gas over the duration of the contract, usually 20 – 25 years.

This paper examines the risk exposure an off-taker can bear under a TOP obligation and how these risks evolve with liberalisation within the contest of the emergence of global spot markets for gas. Empirical evidence tends to suggest that in order to mitigate volume and price risks, sufficient flexibility in the form of renegotiation clause should be introduced into the TOP obligation. This is to enable parties to adjust the long term Gas Sales Agreement in order to accommodate changing market conditions. Further, transition towards shorter term contract has the capacity to reduce the risk faced by the off-taker under a longer term TOP obligation.
Overcoming Limitations of Empirical Steady State Models using Multi Rate Testing, MRT
Authors: Ifechukwu Michaels , Adebowale Oladepo David
Published: July 2015

Gaslifted wells in mature fields have their peculiar characteristics that make them unique, like high water-cut, high GLR, and multiphase flow through the system. Such wells exist and it has being the tradition to model those using empirical steady state models. The objective of this work has been to determine if these empirical models are modeling the wells efficiently or not. Measured data, Multi-Rate Testing, MRT in form of gaslift injection rates and their corresponding liquid rates has been obtained and used as a basis for this research. If they do not model these wells satisfactorily, the project proceeds to determine the reasons and then recommend ways of overcoming these limitations.

The flow through the tubing is part of a system that starts with inflow from the reservoir. Empirical models developed under unique experimental conditions model multiphase flow from the bottom hole to the surface. These models, which include Beggs and Brill, Hagedorn and Brown, take into consideration several flow variables, which include liquid holdup, gas void, and flow regime to determine contributions of hydrostatic head, friction, and acceleration to pressure loss in the tubing. It was discovered that appreciable differences can exist in liquid rates calculated from these models and the measured liquid rates. This means the models are not efficient and the wells are not optimized.

Significant findings of this project are: the reasons for these deviations are centered on inherent flaws in these models. These models cannot capture the dynamic conditions of a gaslift well which produces liquid in slugs and some do not capture the effect of deviation on pressure gradient. Other reasons for deviation include the L-factor, productivity index, tubing inner diameter changes due to scale, roughness or oversized tubing, correlation model in use, and a combination of these factors. It is recommended that MRT be carried out more frequently.
A P/Z Plot For Estimating Original Gas in Place in a Geo-pressured Gas Reservoir By The Use of A Modified Material Balance Equation
Authors: Obielum I. O. , Giegbefumwen P. U. , Ogbeide P. O.
Published: July 2015

Geo-pressured gas reservoirs are reservoirs with high pressure gradient of about (0.5 – 1.0) psi/ft. The increase in pressures has been proposed by some authors to be caused by inability of excess fluids to leak-off after major tectonic events of compressional folding or rapid deposition of thick sediments in young sedimentary rocks.

The limitation of the conventional method in estimating original gas in place (OGIP) in a geo-pressured gas reservoir is that the solution gas in connate water is habitually neglected in estimating the OGIP. As a result, its contribution of the total gas production is omitted in the MBE. This leads to an inaccurate estimation of OGIP and gas reserve.

To eliminate this error, a new form of MBE is presented by this study. It includes the contribution of solution gas in connate water to the total gas production. A comprehensive compressibility term that includes the rock compressibility (Cf), water compressibility (Cw) and the gas solubility in water (Rsw) are introduced into the material balance equation and P/Z plots are formulated.

The result of the formulation indicates a 5 – 12% increase in the estimation of the OGIP as compared to some existing methods.

This tells the importance of the solubility of gas in brine in the estimation of the OGIP and the importance of its inclusion in the Material Balance Equation.
Benefit of Data Integration (Biostratigraphic Data) in Field Development –B4 Gas Reservoir Case Study
Authors: Ogbuli Andrew , Kakayor Omagbemi , Bahry Alia , Adepoju Yaqub , Awa Chukwunweike , Balogun Olalekan
Published: July 2015

The management of uncertainties associated with ‘green fields' remains a challenge due to data paucity. In the context of rising development costs for oil and gas projects, integration of data from all available sources becomes imperative. This integration has been demonstrated to reduce identified subsurface uncertainties and risks.

Biostratigraphic data which comprises use of forams and fauna from ditch cuttings picked in several reservoirs in the field has been evaluated and is used to delineate the sequence stratigraphic boundaries which have been shown to be useful for building the framework for field correlation, thus the building of realistic static models.

The CAMOY Gas field located onshore Niger Delta basin was discovered in 1961 by CAMO-1 well. To date, a total of six wells have been drilled in the field. The field is split into two fault blocks by CAMO fault (an East-west trending fault) in the south. The minor block is penetrated by just one well, with the remaining five wells in the main block. A total of nine hydrocarbon-bearing reservoirs have been penetrated occurring between the depths of 6500 ftss and 11000 ftss.

Key subsurface uncertainties that impact on the development plan of the B4 gas reservoir have been identified, and they are associated with structure and stratigraphy. A range of static volumes were computed initially based on the original understanding of the underlying structural and stratigraphic uncertainties. However, by integrating biostratigraphic data in the reservoir correlation, the uncertainty associated with stratigraphy is reduced, leading to a more realistic range of volumes.

Following the building of a realistic 3D model and volume ranges, two wells have been proposed to be drilled to develop the reservoir. The placement of one of the wells closer to the CAMO fault has been optimized post application of biostratigraphic data in B4 gas reservoir correlation.
The Analysis of String Stability Affected by Earthquake in the Shallow of Deep-water Drilling
Authors: Zhou Y. , Fan H. , Deng S. , Shen W. , Li W
Published: July 2015

The analysis of string stability affected by earthquake in the shallow of deepwater drilling

In deepwater drilling, wellhead, catheter, surface casing system and riser are linked together, they show the characteristic of instability under the influence of wave force. Some scholars have already done some research on this topic, however, the shallow sea is an area with frequent earthquake. Especially in some active seismic zone, oil and gas are often accompanied by earthquake, so it is crucially important to study the seismic forces on deep-water shallow wellhead, catheter and surface casing.

On account of the dynamic pile soil, the paper firstly studies the classification of the shallow soil properties. The paper carries on an overall study as landing depth of surface casing is about establishes the neural network model, considering the length, diameter, vertical pressure, casing pipe weight, soil properties, pore pressure, shallow properties of drilling fluid and especially the seismic characters of surface casing string. The influence of earthquake on the casing string stability will be gotten from these data collected after neural network analysis and calculation.

Based on the geological characteristics of Yingqiong basin, this paper establishes the neural network input and output bridge, obtains the earthquake effect on shallow casing string, and get the following conclusions: 1. Natural environment and other factors have certain effects on the casing string stability; 2. Traverse force on casing string increases by the earthquake action; 3. The earthquake has greater influence on the wellhead stability; 4. Shallow casing string vibration frequency can be obtained during earthquake action.

Study of Vibration of casing string in deep-water has been the difficulty of research. As many accidents happened due to multiple factors, shortages in current study, it is particularly important to research on how to build a deep shallow casing string vibration model, especially considering the uncertainty of seismic force. Importance of this paper is the further study of the influence of the seismic force.
Displacement Calculation of Dynamic Killing Drilling In Deepwater
Authors: Ren W. , Fan H. , Deng S. , Cui C. , Peng Q , Liu X. , Dou X.
Published: July 2015

The dynamic kill process is divided into two stages: “dynamic pressure stability” and “static pressure stability” stage in this paper. In dynamic pressure stability stage, sea water fluid was pumped into the well the initial killing fluid; Then in “static pressure stability” stage, pump into the weight liquid by quantified displacement based on “dynamic pressure stability” that can achieve complete killing effect, and control well kick effectively to drill efficiency.

In this paper, the multiphase multicomponent staged pressure control equation is established by considering the effect of shallow flow gas influx, meanwhile, it adopts the auxiliary equations such as velocity equation, density equation, and Herschel-Bulkley fluid rheological equation with yield value. The dynamical drilling tools flow pressure loss method is considered to improve the calculation accuracy of displacement. This paper solves the equation by the finite difference iterative method which should get the solution conditions firstly, then the initial and weight displacement are got.

This paper takes a deepwater well as an example by comparing and analyzing calculation results and the actual data which shows that it has a greater degree anastomosis with the actual construction site. The following conclusions are obtained: (1) Calculation accuracy is more precise and practical when using the Herschel-Bulkley rheological model and considering the dynamical drilling tools pressure loss calculation (2) The emphasis of finite difference iterative method are grid division and the boundary conditions determination. (3) The prevention of shallow geological disaster is more effective and the process is more delicate by dividing the progress into two stages.

With oil and gas area trend diverting from land to sea, from the superficial to deep, the drilling and mining condition is becoming more and more complex. The method proposed in this paper can not only solve the complex well kick in deepwater which can't be solved before, but also the multicomponent multiphase equation established make the control of shallow flow gas more subtly, and the calculation equations of high accuracy displacement built by stages make the kill process more systemic.
Alkaline-Surfactant-Polymer Flooding for Heavy Oil Recovery from Strongly Water Wet Cores Using Sodium Hydroxide, Lauryl Sulphate, Shell Enordet 0242, Gum Arabic and Xanthan Gum
Authors: Solomon Ujuanbi , Oluwaseun Taiwo , Olalekan Olafuyi
Published: July 2015

Among the world's natural sources of energy, petroleum stands out as the largest contributing mineral. This makes it the most sought-after mineral. Methods for oil recovery are constantly studied, and innovations are being made to improve the recovery of oil. Chemical Enhanced oil recovery (EOR) process is therefore at the fore-front of these studies and innovations.

The research work presents a comparative study of the core flooding carried out with different Alkali/Surfactant/Polymer (ASP) slugs formulated using sodium hydroxide (NaOH) an alkaline, surfactant being Lauryl Sulphate and Shell Enordet and polymer- gum Arabic and Xanthan gum.

The result shows that the ASP slug of Xanthan gum with Shell Enordet 0242 and Lauryl Sulphate had the highest displacement efficiency of 71.23% and 49.51% respectively. The others ASP slug formulated with gum Arabic and Shell Enordet or Lauryl Sulphate gave an efficiency of 31.36% and 32.20% respectively.

For heavy Oil recovery, the use of Shell Enordet 0242 or Lauryl Sulphate and Xanthan gum or gum Arabic will improve recovery. However, Xanthan gum gave a more stable displacement front than gum Arabic. Therefore, a higher concentration of gum Arabic is recommended for better recovery.
Utilizing Early Time Boundary-Dominated Flow Data to Make an Initial Estimate of Gas-in-Place: An Aid to Computing Material Balance Pseudotime
Authors: Damoah L. O. , Mohammed S. , Enty G. S.
Published: July 2015

We investigate, through a graphical representation of dimensionless pseudocumulative function, the possibility of using only the early time boundary-dominated flow (BDF) data to make an initial estimate of gas-in-place. In particular, we demonstrate that when viscosity-compressibility product ratio is plotted against fractional recovery on linear coordinates, an early straight line is observed during BDF regime. This phenomenon permits the dimensionless pseudocumulative function to be expressed as a quadratic function which, upon approximation, yields a linear function in terms of fractional recovery. This work thus demonstrates that the utilization of actual cumulative in gas flowing material balance yields two negative slopes − early time and late time BDF lines. As opposed to the late time BDF line, the early time BDF line yields a reasonable initial gas-in-place, and thus considerably reduces the number of time-consuming iterations associated with computing material balance pseudotime function. Perhaps, the significant finding of this work is that it establishes that the approximate gas flowing material balance equation is strictly applicable to the early time BDF data. Simulated and field data for both single- and multi-well systems are presented to demonstrate the applicability of the proposed approach.
Emulsion Treatment in the Oil Industry: A Case Study of Oredo Field Crude Oil Emulsion
Authors: Augustina Ovuema , Sylvester Okotie
Published: July 2015

The formation of emulsion is one of the challenges facing the oil and gas industry today. This is normally encountered when water is dispersed as fine droplets in the bulk of oil. This study presents the treatment techniques used by Nigeria Petroleum Development Company in Oredo field in breaking crude oil emulsion. Wells 2L and 4L were used for the analysis. Crude samples were obtained at the upstream of chemical injection points to ensure the samples were true representatives of the crude from the wells in the field. Chemical demulsifiers (DM1, DM3, DM4, and DM5) were formulated in the laboratory which was used in the treatment of 100ml of emulsion. Results show that DM3 and DM5 were the most effective chemical demulsifiers formulated in the laboratory for Oredo wells 2L and 4L respectively and also, temperature is an indispensable determining factor in the treatment of emulsion.
Hydrocarbon Resource Development Decision for Gas Reservoir with 10ft Oil Rim: Niger Delta Case Study
Authors: Balogun Olalekan , Adepoju Yaqub , Ogbuli Andrew , Chukwunweike Awa
Published: July 2015

The presence of oil rim in gas reservoirs could potentially have an impact on the timing and philosophy of gas development in the field. Sound reservoir management strategy requires investigation of the development feasibility of the oil rim as part of the field development planning study. This is also a prerequisite to securing regulatory approval for the resulting field development plan.

Eleju C1000 reservoir contains a proven 10ft oil rim with a huge gascap supported by clearly logged fluid contacts. The field is located onshore Niger Delta, with six well penetrations, leading to the discovery of nine hydrocarbon-bearing sands. The field development concept is based on the gas resource in C1000 reservoir, which holds over 80% of the estimated field gas in-place volume.

Based on the available geoscience and engineering data, analytical and simulation methods were employed to evaluate the feasibility of developing the 10ft oil rim in C1000 reservoir. The operator's Oil Rim Development Guidelines and Wyne et al Matrix (for evaluating oil reservoir feasible concept) were employed in selecting an optimum development concept for the C1000 reservoir.

Analytical and simulation methods resulted in C1000 estimated EUR per well range of 0.3 – 0.4 MMstb with a unit development cost (UDC) of about $100/bbl excluding flowlines and facility. This is not economically favourable to the project which has a UDC of $3.4 per boe for gas development only. Therefore, the optimum development option for reservoir C1000 is gas development only.
Design of a Coordinates Aware Remote Module for Effective Oil and Gas Pipeline Monitoring Using GPRS, GPS and Google Maps on Android Devices
Authors: Ileanwa Ocheja Patrick , Ngozi Ezeanyagu Obianuju , Chigozie Udeh Paschal , Eyo Abu Abu
Published: July 2015

The incessant and malicious damage of oil and gas pipeline has continued to impose more challenges on production, transportation and utilization of oil and gas resources. This menace has led to loss of lives and properties, environmental pollution and degradation as well as adversely affected the economy of some countries negatively. With industry professionals rising to the occasion, electronic systems remain one of the potential technologies to be considered. This paper aims at addressing security challenges faced by oil and gas industries with greater emphasis on oil and gas pipeline security. It also unveils a design of an intelligent security system capable of detecting and tracking intruders within a specified perimeter and also real time transfer of data from such locations of security breach to remote devices. Data collation on location is achieved using GPS and Google Maps API enhanced to accurately locate the routes of pipelines. Security breach is detected through the use of sensor networks and consequent real-time communication to a mobile application is realized through a GPRS module and Android operating system. This work presents an opportunity for existing and emerging economies to combat oil and gas theft which maximizes profit.
Optimality Test of Marginal Field Development Financing Arrangements in Nigeria
Authors: Ekeh Chibueze , Asekomeh Ayodele
Published: July 2015

Marginal oil fields in Nigeria, some of which the International Oil Companies (IOCs) have abandoned for over 10 years previously, are now being awarded to indigenous oil companies. Due to difficulty with raising development finance domestically, some of the indigenous Marginal Field Operators (MFOs) have resorted to allowing foreign-listed Financial Partners (FP) to ‘carry’ their share of development costs. We test the optimality of such ‘carried’ cost arrangements by using the discounted cash flow method to analyse the economic viability of two model marginal fields (one onshore and the other offshore) in the Niger Delta/Gulf of Guinea region. Four different scenarios (sole risk [MFO], sole risk [FP], joint venture without carry, and joint venture with carry) for each model are compared. The empirical results appear to imply that marginal field operators are better off if they can contribute their share of development costs, by equally sourced debt and equity financing domestically, than when they are carried by a foreign financial partner. The computed net present value (NPV), NPV per barrel, modified internal rate of return (MIRR) and payback period all show that carrying of interest favours the FP over the MFO in a joint venture arrangement. Additionally, oil price and Petroleum Profit Tax (PPT) have the greatest impact on NPV in both models.
Development of Cost Effective Surfactants from Local Materials for Enhanced Oil Recovery
Authors: Adeniyi A. T , Onyekonwu M. O , Olafuyi O. A , Sonibare L.O. O
Published: July 2015

Surfactants are used to lower surface/interfacial tension in crude oil reservoir, and hence increase oil mobility. Niger Delta Oilfields are matured and may be said to be characterized with heavy hydrocarbons. The heaviness is a result of years of associated gas flaring; leaving behind only oil. It is imperative to inject surfactants to mobilize oil column through flooding. Unique local raw materials have been identified and developed to form Ibile Surfacs. Ibile Surfacs is biodegradable, easy to formulate and readily available as oilfield chemicals. Three branded market samples of surfactants were collected for comparative studies, with the Ibile Surfacs. Branded market samples obtained are Tween 80, Lauryl Sulphate, and Teepol. Some of the test conducted for the samples are stability under similar temperature values, environmental biodegradability, ability to foam and sustain foaminess with saline water and hard water respectively. The result obtained for biodegradability shows that, the Ibile Surfac maintain reasonable leads ahead of Lauryl Sulphate and Teepol and similar characteristics with Tween 80. Results obtained for stability under the same temperature values, reflected equal trends for Tween 80, Lauryl Sulphate, and Teepol with Ibile Surfacs showing a lead. Similarly, a table of results tabulated for foamability and foaminess sustainability gave strong indications that Ibile Surfacs foamed continuously in hard water. Whereas, Tween 80, Lauryl Sulphate, and Teepol broke down at moderates water hardness. It can be safely stated that, Ibile Surfacs is better than trio of sampled market brands, and can be use to replace either Tween 80 or Lauryl Sulphate, and/or Teepol.
When is a Good Citizen Valued More? Organizational Citizenship Behavior and Performance Evaluation
Authors: Oh Se Hyung (David) , Chen Ying , Sun Fubin
Published: July 2015

Organizational citizenship behaviors (OCB) have been found to affect supervisors' ratings of employee performance partially because these behaviors are distinct and, thus, capture the rater's attention. In this study, we have expanded the existing literature by recognizing the rater's
readiness to detect employee OCB. Specifically, we applied the concept of bottom-up and top-down attentional capture to test our prediction that the influence of OCB on employee performance evaluation would be dependent upon the rater's motivation to detect behaviors that potentially increase
group effectiveness. Results of hierarchical linear modeling analysis of data collected from 33 work groups at 5 state-owned manufacturing factories in China supported our hypotheses. Our findings suggest that the relationship between OCB and performance ratings is more complex than originally
thought and that both rater's cognition and group context should be taken into consideration when investigating this relationship.
Interpersonal Trust and Self-Perception of Heterosexual Charm Moderate Potential for Betraying One's Romantic Partner
Authors: Tu Yangjun , Chen Yaguang , Guo Yi , Yang Zhi , Jiang Xin
Published: July 2015

We examined whether or not interpersonal trust and self-perception of one's heterosexual charm moderated the potential to betray one's romantic partner. To enable free expression, we asked college students (N = 271) to imagine the possibility of a relationship breakup occurring
between couples described in 4 vignettes. The results showed that the men believed that couples were more likely to break up when the woman in the partnership experienced a dramatic change for the worse in her physical appearance, but the women thought that couples were more likely to break
up when the man in the partnership experienced a dramatic worsening of his economic status. Interpersonal trust and self-perception of heterosexual charm more strongly affected the perception of the male participants that a couple would break up when there was a change for the worse in the
physical appearance of the woman partner, and these 2 factors also strongly affected the perception of the female participants that a couple would break up when there was a dramatic worsening of the economic status of the man in the partnership.
Inclusive Leadership and Work Engagement: Mediating Roles of Affective Organizational Commitment and Creativity
Authors: Choi Suk Bong , Tran Thi Bich Hanh , Park Byung Il
Published: July 2015

We examined the mediating roles of affective organizational commitment and employee creativity in the relationship between inclusive leadership and employee work engagement. Participants were 246 employees of 6 companies in the services industry in Vietnam, and they completed the Employee
Work Engagement Scale, Inclusive Leadership Scale, Affective Organizational Commitment Scale, and Employee Creativity Scale. We found that inclusive leadership was positively related to employee work engagement, and that both affective organizational commitment and employee creativity mediated
this relationship. Our findings represent a theoretical contribution to social exchange theory and provide useful managerial implications for organizations to improve work engagement among employees.
How Depression Stigma Affects Attitude Toward Help Seeking: the Mediating Effect of Depression Somatization
Authors: Wang Xia , Peng Shun , Li Huang , Peng Yunshi
Published: July 2015

We investigated the relationships among the social stigma associated with depression, somatization of depression-related symptoms, and help seeking. Participants were 357 Chinese undergraduate students. Stigma, somatization, and help seeking were measured with a neuropsychological assessment
and validated clinical scales. We performed a path (principal components) analysis of the role of somatization as a mediator in the relationship between depression stigma and help seeking, and found that the hypothesized mediation model fit the data well. Our results confirm previous findings
on the mediating role of depression somatization in the relationship between depression stigma and attitude towards help seeking. The identification of mediators contributes to the understanding of the mechanisms that prevent help seeking among Chinese college students.
Online Emotion Regulation Questionnaire for Adolescents: Development and Preliminary Validation
Authors: Xie Dengfeng , Lu Jiamei , Xie Zhangming
Published: July 2015

Emotion regulation when using the Internet is an increasingly important way to secure effective social functioning for adolescents. To develop a measure of emotion regulation for adolescents with reference to the network community and examine its reliability and validity, we recruited
535 young people as participants and performed item analysis, identification degree analysis, exploratory factor analysis, and confirmatory factor analysis. Our results showed that the online emotion regulation of adolescents comprised the following 4 dimensions: positive emotion seeking,
negative emotion experience, interpersonal emotion support, and mood awareness. Cronbach's α coefficient and the test–retest reliability met the benchmark psychometric standards, and the confirmatory factor analysis demonstrated that the scale had a good fit. Our results indicated
that the developed scale was a valid and reliable measure of adolescents' online emotion regulation.
Elevated Hepatic miR-22-3p Expression Impairs Gluconeogenesis by Silencing the Wnt-Responsive Transcription Factor Tcf7
Authors: Kaur Kirandeep , Vig Saurabh , Srivastava Rohit , Mishra Akansha , Singh Vijay Pal , Srivastava Arvind K. , Datta Malabika
Published: July 2015

Levels of miR-22-3p, a highly abundant hepatic microRNA, are abnormally increased in mouse models of insulin resistance and type 2 diabetes, yet its contribution to deregulated hepatic metabolism under diseased states is not well understood. Here, we unravel a novel link between elevated hepatic miR-22-3p expression and impaired gluconeogenesis in diabetic db/db mice via the regulation of Tcf7 (transcription factor 7). Our data demonstrate that miR-22-3p binds to the 3′ untranslated region of TCF7 and downregulates it, and this microRNA-mediated regulation of TCF7 increases the expression of enzymes of the gluconeogenic pathway in HepG2 cells. Small interfering RNA–mediated knockdown of TCF7 in HepG2 cells also causes similar upregulation of gluconeogenic genes. Furthermore, in vivo silencing of miR-22-3p by antagomiR administration lowered random as well as fasting glucose levels in diabetic mice. miR-22-3p antagonism improved glucose tolerance and insulin sensitivity. Importantly, the hepatic Tcf7 levels were restored along with reduced hepatic glucose output, which was also reflected by the decreased expression of gluconeogenic genes. Our results support a critical role for miR-22-3p and its target, Tcf7, in the pathogenesis of diabetes by upregulating gluconeogenesis. Moreover, targeting the miR-22/Tcf7/Wnt axis might hold therapeutic potential for the treatment of altered hepatic physiology during insulin resistance and type 2 diabetes.
An Application of an Expert Method for M-28 Aircraft Maintenance Support / Zastosowanie Metody Ekspertowej Do Wspomagania Eksploatacji Samolotu M-28
Authors: Golański Piotr
Published: July 2015

A concept of an expert system that can be used for supporting aircraft diagnostic and maintenance processes is presented in the paper. The paper discusses general principles of an expert system creation as well as main tools used for implementation of such a system. A method of application of one of those tools - CLIPS expert system shell, for solving M-28 aircraft maintenance problems is presented in the paper.
Jet Fuels Degradation under Severe Thermal Loads / Degradacja Paliw Lotniczych W Warunkach Wysokich Temperatur
Authors: Sarnecki Jarosław
Published: July 2015

Paper presents research results of jet fuels thermal degradation exposed to different thermal loads. This problem is especially important as it influences safety of aircraft operation. Jet fuel in modern engines is used in heat transfer and cooling of different construction elements. Together with new engines’ construction and materials used thermal loads affecting jet fuel become more severe, and thus in aircraft fuel system not well understood phenomena occur, resulting with plugging injectors, valves and affecting elastomers. They affect engine operation and should be well and carefully described and understood to prevent them. Research results presented here are the first data in Poland dealing with jet fuels’ thermal degradation problem. Article is aimed to present the mechanism of jet fuel thermal degradation under different temperatures. The project has been funded by National Science Centre granted with decision no. DEC-2011/01/D/ST8/06567.
Possibilities Concerning Diagnosis of the SSP-FK Aircraft Fire Suppression System in Terms of Determination of Reasons for False Fire Alarms / Możliwości Diagnozowania Lotniczego Systemu Przeciwpożarowego Ssp-Fk W Aspekcie Określania Przyczyn Fałszywego Sygnalizowania Pożaru
Authors: Szelmanowski Andrzej , Borowski Jerzy , Głyda Krzysztof
Published: July 2015

The paper presents selected results of work at the Air Force Institute of Technology (AFIT) in the scope of testing of the SSP-FK fire suppression system used on many types of military aircraft operating in the Polish Armed Forces. For the purpose of determining conditions for false fire alarms, SSP-FK simulation models have been developed. The study was carried out on simulation models in Matlab-Simulink and Circuit-Maker packages. Results of this work have been used for diagnosis of the SSP-FK system during a test of real cases of false activation of these devices.
The Evaluation Metod of Transport System on the Basis of Semi-Markov Model of the Operation and Maintenance Process / Metoda Oceny Systemu Transportowego Na Podstawie Semimarkowskiego Modelu Procesu Eksploatacji
Authors: Woropay Maciej , Migawa Klaudiusz
Published: July 2015

The article presents a method for assessment of availability and risk functioning of technical objects (transport means) in an executive subsystem. Indexes of the availability and risk connected with functioning of a single technical object have been determined on the basis of a mathematical model of the operation and maintenance process, in the studied transportation system. A Mathematical model of the operation and maintenance process has been developed with acceptance of an assumption that the process model is to be represented by a homogeneous Markov model X(t).
Computer Aided Diagnosis of Technical Condition of the SWLP-1 Helmet Mounted Flight Parameters Display System / Komputerowe Diagnozowanie Stanu Technicznego Systemu Nahełmowego Wyświetlania Parametrów Lotu SWPL-1
Authors: Michalak Sławomir , Borowski Jerzy , Szelmanowski Andrzej
Published: July 2015

The paper presents selected results of the work carried out at the Air Force Institute of Technology (AFIT) in the scope of computer diagnostic tests of the SWPL-1 Cyklop helmet mounted flight parameters display system. This system has been designed in such a way that it warns the pilot of dangerous situations occurring on board the helicopter and threatening the flight safety (WARN) or faults (FAIL), which inform about a failure in given on-board equipment. The SWPL-1 system has been awarded the Prize of the President of the Republic of Poland during the 17. International Defense Industry Exhibition in Kielce.
Development of a Questionnaire to Investigate Study Design Factors Influencing Participation in Gait Rehabilitation Research by People with Stroke: A Brief Report
Authors: Patterson Kara K. , Gallant Nicole , Ormiston Tracey , Patience Chad , Whitechurch Mandy , Mansfield Avril , Brown Janet
Published: July 2015

Purpose: The main objective of this study was to evaluate the feasibility of a newly developed questionnaire to assess the influence of study design on participation in gait rehabilitation research in a pilot test with individuals with stroke. A secondary objective was to investigate the relationship between participation in gait rehabilitation research and social and clinical factors of interest after stroke. Methods: A questionnaire was developed with expert opinion and guidance from related previous research. The questionnaire was pilot tested in a group of 21 people with stroke, and social and clinical factors (including gait function) were collected. Gait function was assessed using a pressure-sensitive mat; social and clinical characteristics were extracted from patient charts. Correlations were performed to investigate relationships between questionnaire responses and gait function, motor impairment, and chronicity; t-tests were used to examine response differences between people with a caregiver at home and those without. Results: A total of 21 people with stroke completed the questionnaire without difficulty; mean completion time was 7.2 (SD 3.5) minutes, with a range of responses across participants. Borderline significant associations were found between gait function and the number of studies in which a person would participate and between stroke chronicity and the location of studies in which a person would participate. Conclusions: A questionnaire to investigate the influence of study design factors on participation in rehabilitation research is feasible for administration in the post-stroke population and has potential to inform the design of future studies.
Physical Activity Participation and Preferences: Developmental and Oncology-Related Transitions in Adolescents Treated for Cancer
Authors: Wright Marilyn
Published: July 2015

Purpose: To describe motor function and participation in, barriers to, and preferences for physical activity (PA) in adolescents during and after treatment of cancer and to discuss PA promotion in the context of developmental and cancer transitions. Method: A cross-sectional survey study used the Transfer and Basic Mobility and Sports/Physical Functioning self-report and parent-report scales of the Pediatric Outcomes Data Collection Instrument (PODCI) and questions about PA participation and preferences to collect information from 80 adolescents and 63 parents. Results: PODCI scores for adolescents receiving treatment were more variable and significantly lower than those of adolescents who had been off treatment for more than 2 years. Fatigue, pain, general health, and doctor's orders were frequently identified as barriers to PA for adolescents receiving treatment. Many did not achieve recommended levels of PA. The adolescents expressed preferences for being active with friends and family, at home or in school, in the afternoon or evening, and through daily recreational and sports activities typical of teenagers. Conclusions: Physical abilities and participation in and barriers to PA vary across the cancer journey. Interventions should be sensitive to variability and acknowledge individual preferences and environments throughout the trajectories and transitions of cancer treatment and youth development to achieve lifelong healthy lifestyles.
Reliability of the Berg Balance Scale as a Clinical Measure of Balance in Community-Dwelling Older Adults with Mild to Moderate Alzheimer Disease: A Pilot Study
Authors: Muir-Hunter Susan W. , Graham Laura , Montero Odasso Manuel
Published: July 2015

Purpose: To measure test–retest and interrater reliability of the Berg Balance Scale (BBS) in community-dwelling adults with mild to moderate Alzheimer disease (AD). Method: A sample of 15 adults (mean age 80.20 [SD 5.03] years) with AD performed three balance tests: the BBS, timed up-and-go test (TUG), and Functional Reach Test (FRT). Both relative reliability, using the intra-class correlation coefficient (ICC), and absolute reliability, using standard error of measurement (SEM) and minimal detectable change (MDC95) values, were calculated; Bland–Altman plots were constructed to evaluate inter-tester agreement. The test–retest interval was 1 week. Results: For the BBS, relative reliability values were 0.95 (95% CI, 0.85–0.98) for test–retest reliability and 0.72 (95% CI, 0.31–0.91) for interrater reliability; SEM was 6.01 points and MDC95was 16.66 points; and interrater agreement was 16.62 points. The BBS performed better in test–retest reliability than the TUG and FRT, tests with established reliability in AD. Between 33% and 50% of participants required cueing beyond standardized instructions because they were unable to remember test instructions. Conclusions: The BBS achieved relative reliability values that support its clinical utility, but MDC95and agreement values indicate the scale has performance limitations in AD. Further research to optimize balance assessment for people with AD is required.
Evidence-Based Management of Postural Control in a Child with Cerebral Palsy
Authors: MacKenzie Claire , McIlwain Susan
Published: July 2015

The authors review and discuss the evidence exploring the use of dynamic compression garments with children with cerebral palsy. The evidence is presented in case-study format with a focus on postural control and impact on involuntary movements.
Intra- and Inter-session Reliability of Static and Dynamic Postural Control in Participants with and without Patellofemoral Pain Syndrome
Authors: Akhbari Behnam , Salavati Mahyar , Mohammadi Farshid , Safavi-farokhi Ziaeddin
Published: July 2015

Purpose: To determine the intra- and inter-session reliability of balance performance in people with patellofemoral pain syndrome (PFPS) and matched controls. Methods: In this methodological study, single-leg-stance performance of 15 participants with unilateral PFPS and 15 healthy matched controls was assessed using the Biodex Balance System (BBS) under 4 task difficulty levels (static and dynamic, with and without visual feedback). Intra-class correlation coefficients (ICCs), standard errors of measurement, and coefficients of variation were calculated for the overall stability index, anterior–posterior stability index, and medial–lateral stability index. Results: Static and dynamic postural performance during single-leg stance showed moderate to very high reliability in the PFPS group (ICCs=0.53–0.96) and in healthy control participants (ICCs=0.51–0.91). Both measures were more reliable with eyes closed than with eyes open. Conclusion: BBS stability indices appear to have acceptable reliability in people with PFPS, particularly in more challenging conditions, and may be incorporated into the evaluation and rehabilitation of this patient group.
Mapping the Physiotherapy Profession in Saskatchewan: Examining Rural versus Urban Practice Patterns
Authors: Bath Brenna , Gabrush Jeffery , Fritzler Rachel , Dickson Nathan , Bisaro Derek , Bryan Kyla , Shah Tayyab I.
Published: July 2015

Purpose: People living in rural and remote regions need support to overcome difficulties in accessing health care. The objectives of the study were (1) to compare demographic characteristics, professional engagement indicators, and clinical characteristics between physiotherapists practising in rural settings and those practising in urban settings and (2) to map the distribution of physiotherapists in Saskatchewan. Method: This cross-sectional study used de-identified data collected from the 2013 Saskatchewan College of Physical Therapists membership renewal (n=643), linked with the Saskatchewan Physiotherapy Association's (SPA) 2012 membership list and a list of physiotherapists who had served as clinical instructors. Employment location (rural vs. urban) was determined by postal code. Results: Only 11.2% of Saskatchewan physiotherapists listed a rural primary employment location, and a higher density of physiotherapists per 10,000 people work in health regions with large urban centres. Compared with urban physiotherapists, rural physiotherapists are more likely to provide direct patient care, to provide care to people of all ages, and to have a mixed client level, and they are less likely to be SPA members. Conclusions: Rural and urban physiotherapists in Saskatchewan have different practice and professional characteristics. This information may have implications for health human resource recruitment and retention policies as well as advocacy for equitable access to physiotherapy care in rural and remote regions.
Clinical and radiological cervical spine evaluation in retired professional rugby players
Authors: Brauge David , Delpierre Cyrille , Adam Philippe , Sol Jean Christophe , Bernard Pierre , Roux Franck-Emmanuel
Published: July 2015

OBJECT

Acute cervical spine injuries have been extensively studied in high-level contact sports. However, the relation between the appearance of degenerative cervical spine disease and the exposure to repeated trauma in such sports as rugby is still unclear. Using clinical and MRI evaluation, we aimed to determine if former professional rugby players had more serious degenerative cervical spine symptoms than the general population.

METHODS

Two groups, one composed of 101 former rugby players (all men, mean age 40.3 years, range 35–47 years, SD 2.3 years) and the other of 85 male volunteers serving as a control group (mean age 41.6 years, range 35–49 years, SD 4.5 years) were studied. The former rugby players were evaluated on average 5.8 years after retirement (range 1–16 years, SD 3.5 years). The groups were matched in terms of sex, age, job, current sports training, and smoking habits. Each participant received a complete neurological evaluation. Clinical symptoms were evaluated using the Japanese Orthopaedic Association (JOA) questionnaire, and chronic neck pain was specifically evaluated using a visual analog scale (VAS) and the Neck Disability Index (NDI). Overall, 25 MRI studies were performed in each group. MRI studies, including dynamic sequences, focused on degenerative lesions (Matsumoto score and canal diameter) and on muscular and medullary morphological analysis.

RESULTS

Significantly more former rugby players than controls complained of chronic neck pain (51 [50.50%] of 101 vs 27 [31.76%] of 85, p = 0.01). Rugby players also had significant reductions of neck mobility. Nevertheless, in those complaining of pain, there was no statistically significant difference between groups with respect to VAS and NDI scores (p = 0.57). On MRI, former rugby players had a narrower vertebral canal (on average 0.88 ± 0.167 cm vs 0.99 ± 0.130 cm, p = 0.007) and more foraminal stenosis (p = 0.01). No significant difference in the Matsumoto score was found between the 2 groups with respect to other degenerative lesions. Former rugby players had more often undergone surgery for a degenerative condition than had members of the control group (10 cases vs 0 in the control group, p = 0.0021).

CONCLUSIONS

A few years after retirement, former professional rugby players seem to have more frequent cervical spine pain and MRI degenerative lesions, such as foraminal stenosis and narrowing of the spinal canal, compared with controls who had not been professional rugby players. A longer evaluation is necessary to determine if these findings persist over time.
Roles of Chemokines and Chemokine Receptors in Obesity-Associated Insulin Resistance and Nonalcoholic Fatty Liver Disease
Authors: Xu Liang , Kitade Hironori , Ni Yinhua , Ota Tsuguhito
Published: July 2015

Abundant evidence has demonstrated that obesity is a state of low-grade chronic inflammation that triggers the release of lipids, aberrant adipokines, pro-inflammatory cytokines, and several chemokines from adipose tissue. This low-grade inflammation underlies the development of insulin resistance and associated metabolic comorbidities such as type 2 diabetes mellitus (T2DM) and nonalcoholic fatty liver disease (NAFLD). During this development, adipose tissue macrophages accumulate through chemokine (C-C motif) receptor 2 and the ligand for this receptor, monocyte chemoattractant protein-1 (MCP-1), is considered to be pivotal for the development of insulin resistance. To date, the chemokine system is known to be comprised of approximately 40 chemokines and 20 chemokine receptors that belong to the seven-transmembrane G protein-coupled receptor family and, as a result, chemokines appear to exhibit a high degree of functional redundancy. Over the past two decades, the physiological and pathological properties of many of these chemokines and their receptors have been elucidated. The present review highlights chemokines and chemokine receptors as key contributing factors that link obesity to insulin resistance, T2DM, and NAFLD.