bluuebunny/crossref_metadata_2025 huggingface dataset:
Digital Technology Optimizes Unconventional Well Planning by Integrating Cross-Domain Expertise
Authors: Akpenyi Chukwuka , Yuan Zhaoguang , Carson Dan , Hebert Zachary
Published: April 2019

Traditionally, petroleum exploration and development teams have utilized workflows and software which require single instance installation and cater to domain-specific needs. Design results from one domain would require incorporation into applications of other associated domains to deliver team-wide engineering. This is often time consuming, requiring multiple review meetings and extra administrative effort for the drilling engineer.

To add to the complexity, whenever iterations or sensitivity evaluations are needed across the entire plan, there is often no simple platform within which all the required processes can be managed, requiring engineering evaluations to be executed across multiple software. An example is hydraulics which is required for mud design, bottom hole assembly (BHA) and bit design, hole cleaning and borehole stability aspects of drilling. Although all these engineering considerations evaluate the same fluid properties, they typically sit on separate engines and are only integrated by criteria and thresholds in the final plan and not through concurrent engineering design.

This paper presents a new cloud deployed well construction planning solution, that aims to resolve these historical challenges by enabling multiple processes to be connected and executed from a common contextual dataset in a single system. For example, the hydraulics design is coherent across all design tasks which increases planning efficiency and plan quality. The entire solution also integrates across domains, from geology and geomechanics to drilling engineering and service company planning. This coupled with project orchestration, team collaboration and data management provide further productivity gains and cost savings for the entire team.

This paper summarizes the digital well construction planning solution and provides case study examples of how cross domain experts plan concurrently in a single common system. This approach allows a teamwide focus on planning better wells faster in a single engineering solution. Case studies show how the well planning team was able to improve cross-discipline collaboration between engineering and geoscience as well as interactions with service companies. Overall, the well planning time was reduced significantly, and the reliability of the well design was ensured through the engineering validation of each task. The integrated digital well planning solution proved to be a more cost-effective solution for well planning and ensured the high-quality delivery of drilling programs.
Hypervolume-Based Multiobjective Optimization for Gas Lift Systems
Authors: Deng Lichi , Olalotiti-Lawal Feyisayo , Davani Ehsan , Castiñeira David
Published: April 2019

Gas lift is one of the most widely used artificial lift methods, and the use of nodal analysis to generate the gas lift performance curve is well established. However, the optimal gas injection rate is often selected as the point with maximum liquid production, which neglects the cost of incremental injection gas volume. This paper investigates the determination of the optimal operational point using a multiobjective optimization technique by considering the trade-off between gas consumption and oil production. The indicator-based evolutionary algorithm transforms the multiobjective problem into a single objective one using the hypervolume metric computed in the objective space. For the gas lift problem, which is a bi-objective problem aimed at maximizing oil production while minimizing gas injection rate, the hypervolume metrics are identically equivalent to geometric hyperareas under the trade-off curve. The optimization is only applied to the monotonically increasing portion of the gas lift performance curve; thus, all trivial sub-optimal conditions are excluded. The optimal operational point of gas injection rate is determined by finding the maximum rectangular hyperarea under the performance curve. The proper determination of the optimal injection gas rate could not only improve the efficiency of the gas lift itself, but also reduce the burden on the maintenance of surface facilities. The method is also applied to the multi-well scenario where a novel multi-well gas lift performance curve is generated using multiobjective Genetic Algorithm, which could help determine the optimal gas allocation/distribution scenario. The described process is incorporated in an integrated workflow which further leads to fast delivery of analysis/results that enable production engineers to make smarter decisions faster in a repeatable way.
How to Avoid Bottom Hole Assembly Twist Off Challenges in Underreaming While Drilling Operations Using 4D Finite Element Analysis Modelling
Authors: Zhandayev Olzhas , Ungaliyev Gaukharbek , James Biju
Published: April 2019

Historically underreaming while drilling (UWD) operations were implemented in offshore field in Azerbaijan to decrease Equivalent Circulating Density (ECD) and have better hole quality for casing running. Lithology in this UWD, 8.5 × 10.25-inch section consists of sand and shales with 3-5kpsi Unconfined Compressive Strength (UCS). Well trajectory has planned dogleg severity up to 3-3.5 deg/30m. In such a condition underreaming operations are known to be more challenging and complex compared to conventional drilling with bit only. In the offset well, an operator had fatigue related twist off at the reamer's lower sub connection which contributed to 58 hours of NPT.

Our challenge was to come up with the root cause of the twist off and then suggest changes in BHA to avoid this and prove that the modified BHA performs as expected. Our finite element analysis (FEA) based 4D modeling software can identify different vibrations (axial, lateral, stick slip), bending stresses and bending moment of each component in the BHA. Using this software, we were able to come up with the root cause of the twist off, which was due to high bending stress.

In UWD there are two cutting structures in the BHA, so optimizing both cutting structures has a significant impact on the overall performance. Successful run key points are to analyze the underreamer placement in BHA, operating parameters selection for different scenarios (when both bit and undereamer are in the same rocks or when the bit is in soft and undereamer is in hard rock), lateral vibrations and whirling phenomenon which can potentially damage and develop fatigue on BHA components. Multiple BHA's were simulated and based on the results the most stable BHA was recommended for the upcoming well.

The operator implemented the recommended BHA and a total of 1200m was successfully drilled and opened in one run without any NPT. All directional requirements were achieved and both bit and underreamer came out in good condition which confirmed that the new optimized BHA was stable in the downhole drilling conditions. The liner was also run without any issue confirming the borehole quality.

This paper will review the results of analysis and how modeling prediction was validated in the field.
Assessing Mechanical Integrity of Expanding Cement
Authors: Patel Harshkumar , Salehi Saeed , Teodoriu Catalin
Published: April 2019

Cement sheath is a critical barrier for maintaining well integrity. Formation of micro-annulus due to volume shrinkage and/or pressure/temperature changes is the major challenge in achieving good hydraulic seal. Expansion of cement after the placement is a promising solution to this problem. Expanding cement can potentially close micro-annulus and further achieve pre-stress condition because of the confinement. Primary aim of this paper is to investigate mechanical integrity of different pre-stressed cement system under loading condition.

To achieve the objectives, finite element modelling approach was employed. Three dimensional computer models consisting of liner, cement sheath, and casing were developed. Pre-stress condition was generated by modelling contact interference at the cement-casing interface. Three cement (ductile, moderately ductile, and brittle) were considered for simulation cases. Wellbore and annulus pressure were applied. Resultant, radial, hoop, and maximum shear stresses were investigated at the cement-pipe interface to assess mechanical integrity. For comparison purpose, similar simulations were conducted using cement sheath without pre-stress and cement system representing uniform volume shrinkage and presence micro-annulus.

For constant wellbore pressure, the radial stresses observed in all three types of cement system were practically similar and decreased as pre-stress was increased. Hoop stress also reduced with increase in compressive pre-load. However, their absolute values were distinct for different cement types. These results indicate that cement system with compressive pre-load can notably reduce the risk of radial crack failure by providing compensatory compressive stress. However, on the contrary, the maximum shear stress developed at cement-pipe interface, increased because of pre-load. This can compromise the mechanical integrity by reducing the safety margin on shear failure. Thus, the selection of expansive cement should be made after carefully weighing reduced risk of radial failure/debonding against the increased risks of shear failure.

This paper provides novel information on expanding cement from the perspective of mechanical stresses and integrity. Modelling approach discussed in this work, can be used to estimate amount of pre-stress required for a selected cement system under anticipated wellbore loads.
The Need of NMR Cement Properties Characterization and Lesson Learned
Authors: Ichim Adonis , K Saleh Fatemeh , Teodoriu Catalin , Sondergeld Carl
Published: April 2019

Cement is a key element for successful drilling and completing of a well. From oil and gas wells to geothermal applications, cement is a major material ensuring zonal isolation. With an increase in global energy needs and an expected uptick in drilling and plugging and abandonment activities, evaluating and understanding cement properties is crucial, since these properties are used in various engineering designs and calculations. The objective of this paper is to present how Nuclear Magnetic Resonance (NMR) can be used to understand the cement hydration process and the development of key properties such as strength and porosity. NMR applications for cement include determination of porosity, water interactions, identification of hydration stages and C-S-H gel development with curing time. Since water is present in all cement slurries, NMR can potentially help to understand microstructural changes in cement during curing. Data from more than 600 cement specimens cured for more than a year are compiled. Standard cement properties such as UCS (unconfined compressive strength) are compared with NMR responses. In this paper, we document cement hydration and porosity changes through NMR measurements in samples with five different recipes. Our study also confirms a strong correlation between NMR response and cement strength.
Adaptive Forecasting of Natural Gas Resources, Production, Infrastructure, and Prices
Authors: Virine Lev
Published: April 2019

An oil and natural gas producer should continuously analyze industry fundamentals such as supply, demand, storage, transportation, and pricing to make informed operational and business decisions. An oil and gas producer should be able to adapt to frequently changing industry environment by adjusting its operation: increasing or curtailing production, drilling and connecting new wells, obtaining new financing, locking in future natural gas prices, etc. In order to provide an input to the decision-making process, the adaptive management methodology needs to be applied.

Forecasts of hydrocarbon resources, production, infrastructure, and pricing are very sensitive to technological improvements, pricing changes, new discoveries, and other major events, the impacts of which are difficult to predict. One method to improve the quality of a forecast is to apply adaptive management process. The adaptive management methodology implies assuming supply and demand strategy, creating multiple scenarios for allocating oil or gas demand to different areas or regions, evaluating these scenarios, and performing detailed forecast for selected scenarios. One important step of adaptive management is monitoring of actual drilling and production activities. Based on this information original assumptions can be updated.

The result of the analysis is production, prices, and infrastructure forecast. The paper presents an example of a production forecast that is generated using adaptive management process.
Leveraging Improvements in Unitization to Reduce Mobilization Costs for Land Drilling Rigs
Authors: Carpenter Cole , Richards Lee
Published: April 2019

In recent years, an industry-wide demand for increased drilling efficiency has led to the development of technologies and methods focused on multi-well pad development and the minimization of the transportation of drilling rigs between locations. Studies have indicated the potential for improving drilling cycle efficiency through improvements in rig design and procedural documentation but have given limited consideration to the unitization and mobilization practices surrounding ancillary components such as mud pumps, light plants, bulk fluid storage and other systems that comprise modern land rigs. This study examines current unitization practices, as well as offers alternative methods of integrating ancillary system components to improve current transport configurations. Specifically, ancillary systems whose transport dimensions and weight exceed the federal and state requirements for commercial vehicles operating within the National Highway Freight Network (NHFN).

In this study, the application of transport logistics software is used to demonstrate that there exists the potential for significant reduction in land rig mobilization costs through revised unitization of drilling rig ancillary systems. Permit data from proposed wells located in the Permian, Bakken, and Marcellus are utilized to develop transport scenarios whose focus is to quantify the impact of ancillary system unitization on the total fee structure associated with rig mobilization between geographical regions. Within each scenario, ancillary systems from currently active rigs are compiled and itemized according to their weight, transport dimensions, and degree of component unitization. The resulting schedule is then processed through transport logistics software to identify fee schedules associated with oversize permits, overweight permits, civilian and police escorts, driver rate/fuel costs, and associated service fees for the individual loads. Following the conclusions derived from the analysis of the existing rig systems, the series of transport scenarios are repeated using revised component configurations. The revised system employs a combination of divisible and non-divisible loads whose components are either integrated as part of dedicated transport trailers or located within ISO containers loaded onto commercially available transport trailers. The fee schedules from active rigs, as well as the results from the proposed unitization, are explored in detail to identify critical areas for improvement regarding unitization practices for active rigs and future builds.
Field Development Using Compositional Reservoir Simulation and Uncertainty Analysis in the Delaware Basin
Authors: Hefner William , Davudov Davud , Moghanloo Rouzbeh Ghanbarnezhad
Published: April 2019

This study presents a novel, integrated workflow to maximize recovery using PVT compositional modeling, history matching, and numerical reservoir simulation in a tight oil sand formation, the Second Bone Spring. Advancements in unconventional resource development have enabled the Delaware Basin to become highly significant. However, optimizing the development of each formation is still lacking in understanding. This study is one of multiple future studies over tight reservoirs in the Delaware Basin and exhibits a comprehensive approach. Properties that will be optimized are well spacing, reservoir parameters, and EOR feasibility.

To determine the behavior and optimize the development of each of these reservoirs, data from multiple sources was necessary. The data compiled consisted of reports from PVT analysis, completions design, petrophysical analysis, daily production and pressure, deviation surveys, structure and isopach maps, and well design. This data was then implemented into a 3D numerical reservoir simulator (CMG-GEM), first to confirm PVT output in a compositional simulation (CMG-WINPROP), then to simulate up to 20 years of production, and finally to use uncertainty analysis (CMG-CMOST) to optimize reservoir input parameters. Once a base case scenario was established, we then furthered our investigation of well spacing and EOR feasibility by setting up multiple different scenarios for each and running them for 20 years. EOR scenarios included 1-3 month huff-and-puff CO2, as well as low salinity water injection. Results are normalized per foot of completely lateral length and lab data is implemented in EOR simulations.

Our results confirm that reservoir parameters, once established after uncertainty analysis, have a large impact on both optimizing well spacing and EOR feasibility in the Second Bone Spring formation. With each well having very similar cluster spacing, proppant amount and type, and fracturing fluid and type, up to 250 feet of inter-well spacing is unaccounted for. Optimized models show that closer spacing of at least 150 feet can increase EUR estimates an average of 11.25%. An increase of 5-17% recovery is observed once a smaller spacing is implemented. EOR models showed that CO2 and low salinity water injection are viable candidates for the formation (7.25-9% increase for CO2, 6.25% for LSWI).

This integrated study refines our reservoir parameter estimates and helps identify potential to maximize recovery. It suggests that a tighter spacing is necessary to cover a larger portion of the reservoir, as well as showing that EOR is feasible. An improved understanding of the entire reservoir leads to better production and economic estimates.
Well Spacing and Landing Zone Optimization to Improve Development Strategy - A Case Study from the Stack
Authors: Karam Pierre , Yang Junjie , Cozyris Kristian , Stephenson Tim , An Xiaoxuan , Jung Chimok , Jun Jongyoung , Lee Hyungseok
Published: April 2019

Sooner Trend Anadarko Canadian Kingfisher, also known as STACK, is a booming unconventional oil play in North America. As one of the main features that makes the asset profitable, multiple targeting benches raise a challenge of optimization. Well-developed natural fracture system brings in another level of complexity to estimate well spacing. This study introduces an integrated workflow to better understand the fluid flow mechanism in the reservoir and optimize development strategy.

From borehole image log, natural fracture orientation and density was interpreted and statistically populated into geologic model along with petrophysical properties. To account for productivity enhancement due to natural fractures, enhanced permeability was embedded into the simulation model according to the distribution of discrete fracture network. After being history matched, the reservoir model was used to test the sensitivity on well spacing, landing zone and hydraulic fracturing pump schedule. Both infill drilling program and green field development scenarios were tested and compared to optimize our field development study.

Production history match indicates that natural fractures serve as fluid flow conduit and contribute significantly to the production in Osage. Pressure transient observation shows a similar reservoir behavior in the Osage as opposed to the Woodford. Multiple wells experience productivity reduction over longer production history, indicating near-field damage (such as scaling) and/or far-field damage (such as fracture closure). Introduction of skin factor and pressure dependent permeability captured the trend on productivity behavior in the history match. In addition, the simulation study shed light on the hydraulic fracture geometry that provides direct insight on well spacing and landing zone analyses. Results from the infill drilling program show that staggered design with 3 Osage and 4 Woodford wells per section yields the higher oil recovery. However, using the greenfield sensitivities, and depending on the pumping schedule, hydraulic fractures from Woodford wells show upward growth, draining both formations effectively even without Osage wells.

This study provides valuable information about the development strategy in STACK unconventional resources, particularly for scenarios with natural fracture system and multiple targeting zones. The simulation workflow considers well interference in both horizontal and vertical directions simultaneously to optimize oil recovery and reduce operational cost.
Optimal dose of pretreated-dexmedetomidine in fentanyl-induced cough suppression: a prospective randomized controlled trial
Authors: Zhou Wei , Zhang Dongsheng , Tian Shunping , Yang Yang , Xing Zhi , Ma Rongrong , Zhou Tianqi , Bao Tianxiu , Sun Jianhong , Zhang Zhuan
Published: April 2019

Background: To investigate the optimal dose of pretreated-dexmedetomidine in fentanyl-induced cough suppression.
Methods: Patients of 180 undergoing elective surgery with general anesthesia, aged 18-65 years, BMI 18.5-30 kg/m2, ASA I or II, were equally randomized into four groups (n = 45) to receive intravenous pretreatment of dexmedetomidine with 0 (group 1), 0.3 (group 2), 0.6 (group 3) and 0.9 (group 4) mcg/kg over 10 mins, respectively. After the pretreatment, all patients were given a 5-s intravenous injection of fentanyl 4 mcg/kg. The symptoms of irritating cough including the severity and onset time were recorded for 1 min after fentanyl injection. General anesthesia induction was completed with midazolam, propofol and cisatracurium, then endotracheal tube or laryngeal mask was inserted and connected to an anesthesia machine. MAP, HR and SpO2 at the beginning of pretreatment (T0), 3 min (T1), 6 min (T2), 9 min (T3) and 12 min (T4) after the beginning of pretreatment were recorded. Side effects of dexmedetomidine, such as bradycardia, hypertension, hypotension, and respiratory depression were also recorded during the course.
Results: Totally 168 patients completed the study. The incidences of cough were 52.4%, 42.9%, 11.9%, and 14.3% in groups 1, 2, 3, and 4, respectively, with no significant differences between groups 1 and 2 (P > 0.05) and between groups 3 and 4 (P > 0.05). The incidence and severity of cough in groups 3 and 4 were significantly lower than those in groups 1 and 2 (P < 0.05). Compared to T0, HR at T2 (P < 0.05), T3 (P < 0.01), and T4 (P < 0.01) decreased significantly and MAP at T4 decreased significantly (P < 0.05) in group 4. Bradycardia occurred in 1 case and respiratory depression occurred in 1 case in group 4. Compared to group 1, the onset time of cough in the other 3 groups were delayed significantly (P < 0.05).
Conclusion: Pretreated dexmedetomidine 0.6 mcg/kg blous intravenous infusion over 10 mins could reduce FIC effectively without side effects.
EFFICACY OF EXTRAPLEURAL PLOMBAGE WITH SILICONE PLUG IN DESTRUCTIVE PULMONARY TUBERCULOSIS PATIENTS AND ITS IMPACT ON PULMONARY FUNCTIONS AND BLOOD GASES
Authors: Krasnikova E. V. , Bagirov M. A. , Lovacheva O. V. , Popova L. A. , Sadovnikova S. S. , Karpina N. L.
Published: April 2019

The objective of the study: to analyze the efficacy of extrapleural plombage with silicone plug (EPSP) in those suffering from destructive pulmonary tuberculosis with multiple/extensive drug resistance (M/XDR) and to assess EPSP impact on pulmonary functions and blood gases. Subjects and methods. 34 patients with chronic persistent destructive pulmonary tuberculosis who underwent EPSP were enrolled in the study. 23 were men and 11 were women at the age from 18 to 54 years old (the median age made 36.29± 10.2 years). MDR was diagnosed in 31/34 (91.2%) patients, and of them, 22/31 (70.0%) had XDR. A high profile life long breast implants with texturized coating causing no rejection by the host were used for extrapleural plombage. Results. 18 patients who underwent EPSP as a single surgery had their cavities healed in the operated lung in 100% of cases (95% CI 96.3-100%). There were no lethal outcomes. 1/18 (5.6%) patient suffered from a late complication (empyema) related to EPSP. Postponed outcomes of tuberculosis treatment (effective course of treatment after EPSP) were favorable in 13/16 (81.3%; 95% CI 57.0-93.4%) patients. In 11 patients with disseminated destructive tuberculosis who had EPSP combined with resection or collapse surgery, 12/12 (100%; 95% CI 75.8-100%) had their cavities healed in the operated lung; 2/12 patients needed additional bronchial valve block. Surgeries for EPSP resulted in no lethal outcomes or complications. In 5 patients with destructive tuberculosis relapse in the only lung, EPSP was used to stop the progress of the disease due to poor efficacy of chemotherapy. The impact on cavities healing in the operated lung was achieved in 4/5 (80.0%; 95% CI (37.6-96.3%) patients. The complication after EPSP was observed in у 1/5 (20.0%) patient and resulted in the lethal outcome. 3/5 patients had favorable postponed outcomes. After EPSP, ventilation and gas exchange functions deteriorated in 32% of patients, while in 28% of patients, they improved. The intensity of change was moderate or significant. The most dynamic and informative indicators were the vital capacity of the lungs and the partial tension of oxygen in oxygenated blood (PaO2).
GENETIC POLYMORPHISM OF TUBERCULOSIS MYCOBACTERIA IN THE CITY WITH LIMITED POPULATION MIGRATION AND HIGH INCIDENCE OF HIV INFECTION
Authors: Umpeleva T. V. , Belousova K. V. , Golubeva L. A. , Morozova I. M. , Eremeeva N. I. , Vakhrusheva D. V.
Published: April 2019

87 isolates of M. tuberculosis isolated from tuberculosis patients in the Novouralsk municipality in 2013-2016 were studied. It was found out that a high percentage of isolates had multiple drug resistance: 66 and 85.3% among newly diagnosed and previously treated patients, respectively. Genotyping allowed revealing the dominance of isolates of the Beijing family, both among newly diagnosed (75.5%) and previously treated patients (85.3%), with 52.8 and 67.6% of isolates, respectively, belonging to the Beijing B0/W148 variant. MIRU-VNTR-typing detected nine isolates of the Beijing B0/W148 family with an atypical number of repeats in the QUB26 locus (two). A high rate of tuberculosis with concurrent HIV (39.1%) was noted, while in groups of tuberculosis patients with various HIV statuses, no difference was detected in the ratio of multiple drug resistant pathogens and belonging to the Beijing genotype (BeijingB0/W148). The article demonstrates the possibility of using genotyping technologies to confirm/deny the epidemiological relationship between patients and search for previously unknown mechanisms of tuberculosis infection transmission.
Effective decisions for individualized assessment and minimization of the risk of unfriendly takeover of enterprises: the features of the game theory application
Authors: Korolovych Oksana , Chabaniuk Olha , Ostapiuk Natalia , Kotviakovskyi Yurii , Gut Nelia
Published: April 2019

The conditions for doing business at this stage are often similar in a game in which you need to calculate your actions a few steps ahead. At the same time, it is important to highlight several possible current options and make the necessary decision at the control moment. Moreover, each of the options formed should be justified, understandable and take into account the risk factors and available resources.Today, the main problem of assessing and minimizing the risk of “unfriendly takeover” is due to the fact that in most cases the raider is a player who acts quite legitimately and relies on the loopholes of the current legislative framework. Therefore, it is easier to identify possible actions of the raider and to avoid them within the limits of the reverse game than to deal with the consequences.The purpose of the research is to study the specificity of the individualized assessment and minimization of the risk of “unfriendly takeover” by using elements of game theory.It has been taken into account that the effect of individualization in assessing the risk of unfriendly takeover of enterprises can possibly be achieved on the basis of the application of game theory, the elements of which provide simulation of the unfriendly takeover process within the mathematical description of the inherent combinations of attack/defence as if they actually occurred in time both within one state of the external environment and for their given set.The results allowed forming mathematical decision-making models based on the elements of the antagonistic game “raider-target enterprise” and “raider games with the external environment”, which proved the possibility to: 1) identify possible functions of wins/losses; 2) combinations of attacks that can be neglected (that is, from the point of view of the rationality of decisions, will be rejected by the raider); 3) the ranking of the raider’s “attack combinations” for the reliability of their use during “unfriendly takeover”. Under such conditions, the target company can provide not only a detailed assessment, but also an effective minimization of the risk of “unfriendly takeover” and allocate the best combination of protection.
Does the source of water for piped supplies affect child health? Evidence from rural Vanuatu
Authors: Foster Tim , Rand Emily , Sami Erie , Dance Brieana , Kohlitz Jeremy , Willetts Juliet
Published: April 2019

Piped water systems are considered to provide the highest service level for drinking water supplies; however, global monitoring of safe water access pays little attention to the type of water source that piped systems draw upon, even if the water is not treated prior to distribution. This study sought to understand whether the source of water for untreated piped supplies influences the prevalence of diarrhoea among children in rural Vanuatu. The analysis was based on a dataset integrating a Demographic and Health Survey and a nationwide water supply inventory. After adjusting for a range of potential confounders, the results revealed a significant association between diarrhoea and the type of water source supplying a piped system. Compared with borehole-supplied piped systems, spring-fed piped systems were significantly associated with increased odds of diarrhoea (adjusted odds ratio [AOR] 5.8, 95% confidence interval [CI] 1.1–31, p = 0.040). No significant association between diarrhoea and piped systems drawing on surface water was observed. Increased odds of diarrhoea were significantly associated with water supply systems constructed prior to the year 2000 (AOR 4.9, 95% CI 1.9–13, p = 0.001). The results highlight the need for improvements in spring protection as well as ongoing maintenance and periodic renewal of water supply infrastructure.

This article has been made Open Access thanks to the generous support of a global network of libraries as part of the Knowledge Unlatched Select initiative.
Tikhonov well posedness problems of identifying the conditions for fixing mechanical systems
Authors: Akhtyamov A.M.
Published: April 2019

The problem of identification of conditions for fixing distributed mechanical systems by three natural frequencies of their oscillations is considered. Based on the Plücker condition arising when the matrix is reconstructed from its minors of maximal order, a set of well posedness of the problem is constructed and its A.N. Tikhonov well posedness is proved. For a wide class of problems an explicit solution of the problem of identifying the matrix of boundary conditions, written out in terms of the characteristic determinant of the corresponding spectral problem, is found. An example of a solution of a special problem from mechanics is given, as well as a counterexample showing that two natural frequencies generally speaking are not enough for uniqueness of the identification of boundary conditions.
Identification of longitudinal incisions of the beam from its own frequencies
Authors: Akhtyamov A.M. , Karimov A.R.
Published: April 2019

The natural frequencies of bending vibrations of a prismatic beam with symmetrical bilateral longitudinal incisions are considered. A method is proposed that makes it possible to calculate the parameters of the incisions with by two frequencies taken from different spectra. These spectra belong to bending vibrations in two mutually perpendicular planes, which are chosen in such a way that in both cases the neutral cross-section line is parallel to the sides. The dependence of the natural frequency on the depth of the defect is also studied. It is proved that the values of the frequencies for the beam under consideration and the identical beam without cuts do not coincide for any value of the defects.
Numerical modeling of the spill over an impermeable soil
Authors: Gilmanov S.A.
Published: April 2019

All kinds of hydrodynamic processes in the overwhelming majority of cases can have adverse consequences from the point of view of ecology and economics.This requires the development of adequate measures to organize the elimination of the consequences of such events. Mathematical modeling of spills has applied importance for the development of technological equipment designed to reduce the impact of consequences of spills and its prevention.
Constructing exact solutions to anisotropic heat conduction equations by means of conservation laws
Authors: Ibragimov N.H. , Avdonina E.D.
Published: April 2019

Recently the new theorem about conservation laws was proved by N. H. Ibragimov related to the nonlinear self-adjointness definition, and a method of exact solution construction was proposed. In the next paper by the authors, the conservation laws for anisotropic heat conduction equations were constructed. In this work the proposed method is applied to anisotropic heat equations with a source and new exact solutions are constructed.
Combustion of saline propane emission in a canyon between buildings
Authors: Khamidullin I.R.
Published: April 2019

The paper presents the results of numerical calculations of the combustion of a cloud containing propane, based on schemes taking into account the kinetics of chemical reactions. The influence of terrestrial objects on the spread of temperature and pressure fields.
Amplification and attenuation of waves of finite duration by means of a bubble zone in the one-dimensional approximation
Authors: Galimzyanov M.N.
Published: April 2019

Some peculiarities of the dynamics of pressure waves in a fluid containing bubble zone of finite dimensions in the one-dimensional approximation are studied. The problem is considered taking into account nonlinear effects. The results of the action of wave pulses on a bubble area with an uneven distribution of bubbles are presented, as well as effects on a solid wall covered with a bubble area.
The use of virtualization technologies in control systems of micro-robots and microsystems
Authors: Darintsev O.V.
Published: April 2019

When synthesizing control systems of microrobots, the weakest information support is a very serious problem: miniature sizes of robots, limited computing and energy resources do not allow to fully implement all the necessary channels for collecting (processing) information. Some parameters of the external environment and microobjects (microsystems) that have a significant influence on the operational characteristics and functioning of microsystems cann’t be measured: roughness, contact patch profile, magnitude of charge distributed over the surface of the object, etc. The way out of this situation can be the use of virtual information systems built on the basis of intelligent algorithms that allow you to determine the necessary parameters by indirect signs based on expert data and accumulated interaction statistics. In this case, the control system of micro-robots becomes slightly more complicated, information coming from real and virtual measuring systems is not divided: to be a partial
Solution of inverse coefficient problem for fractional anomalous diffusion equation
Authors: Karachurina E.V. , Lukashchuk S.Yu.
Published: April 2019

An inverse coefficient problem is considered for time-fractional anomalous diffusion equations with the Riemann-Liouville and Caputo fractional derivatives. A numerical algorithm is proposed for identification of anomalous diffusivity which is considered as a function of concentration. The algorithm is based on transformation of inverse coefficient problem to extremum problem for the residual functional. The steepest descent method is used for numerical solving of this extremum problem. Necessary expressions for calculating gradient of residual functional are presented. The efficiency of the proposed algorithm is illustrated by several test examples.
The study of the spreading of a drop of water on the surface of a metal by the methods of molecular dynamics
Authors: Moiseeva E.F. , Malyshev V.L.
Published: April 2019

The results of molecular dynamics modeling for the system "water-metal-water vapor" are presented in the article. The method was verified by comparing numerical results with experimental data. The results of numerical modeling of the process of spreading a drop of water over the surface of platinum are presented.
Topological transformations on the droplets in chiral nematic liquid crystals with developed electroconvection
Authors: Timirov Yu.I. , Gareeva E.R. , Scaldin O.A
Published: April 2019

The dynamics and transformations of defects in chiral nematic droplets P in the electric field are studied experimentally, as function of the ratio of the droplet radius R to the helix pitch P. It is shown that, depending on the R/P ratio and the applied voltage, various orientation-structural transformations can be realized. In particular, for the ratio R/P<1 only droplets with one destroyed boojum are observed. The application of an a.c. electric voltage causes the latter to rotate. In the case of R/P~1, the dynamics of the rotation of the disclination line is transform into a periodic decay of the boojum (with a topological index S=1) into two surface defects. In the case R/P>1, a process of merging two surface defects with a topological index 1/2 into a bulk defect of the ”hedgehog“ type with S=1 is observed. The mechanisms of the observed processes are discussed.
Identification of pipeline damage using strain sensors
Authors: Utyashev I.M. , Akhtyamov A.M.
Published: April 2019

There are situations when there is a breakthrough of a pipeline with oil products under water. As a result, oil spills on the surface, polluting the environment. Underwater currents and wind can carry an oil stain away from the point of leakage. Therefore, it is not always possible to visually determine the location of a pipeline break by a spot of oil on the surface.To solve such problems, it is proposed to install strain sensors along the pipeline, which take the values of the displacement derivative ∂u(x,t)/∂x (deformations) at different instants of time, and use the simplest model of a pipeline based on the equations of longitudinal oscillations of a homogeneous rod. Formulas for determining the moment and location of the pipeline rupture were obtained from the strain sensors data and a scheme of interaction with GLONASS was proposed that allows instantly detecting leaks and damages of pipelines laid under water and timely eliminating the consequences of the accident. The application of the proposed scheme minimizes the consequences of the accident for the environment and financial costs.
Statistical Optimization by Response Surface Methodology to Enhance Lipase Production by Aspergillus fumigatus
Authors: Mehta Akshita , Sharma Roji , Gupta Reena
Published: April 2019

Background:

Lipases have various commercial applications and microorganisms serve as a potential source of production.

Objective:

The aim of this paper was to study the effect of interactions among different production parameters on lipase yield ofAspergillus fumigatus.

Method:

Plackett Burman and Central Composite Design (CCD) were established by using Design Expert software 10.0.

Results:

In the present study, interactions were studied for six different variables such as inoculum size, pH, temperature, galactose concentration, peptone concentration and incubation time. In Plackett-Burman design, galactose concentration, peptone concentration, pH and incubation time were found to be important factors. Using the statistical approach, the optimum factors were found to be as: galactose concentration (1.5%), peptone concentration (1.8%), pH (10.0) and incubation time (72 h) at 45°C under response surface curves. Upon statistical analysis, the coefficient of determination (R2) obtained was 0.9318 which showed that the model was significant.

Conclusion:

The statistical tools used predicted the optimal conditions for the production of the lipase. The optimized parameters were galactose concentration 1.5%, peptone concentration 1.4%, temperature 45°C, pH 10.0 and incubation time of 72 h for obtaining a maximum lipase activity of 6.22 U/ml.
Muscle Damage in Different Approaches in Total Hip Arthroplasty According to Serum Markers
Authors: Tottas Stylianos , Fiska Aliki , Kougioumtzis Ioannis , Ververidis Athanasios , Tilkeridis Konstantinos , Drosos Georgios I
Published: April 2019

Background:

Total Hip Arthroplasty (THA) is the final treatment of end-stage hip osteoarthritis. Nowadays, THA has become very common, cost- effective and one of the most successful orthopaedic procedures. Recently, surgeons have shifted their interest to approaches according to Minimally Invasive Surgery (MIS). These approaches are either modifications of conventional approaches or they are designed from the beginning as MIS approaches. Muscle damage and soft tissue damage are issues that concern researchers who perform studies on THA.

Objective:

The aim of this study is to review the literature concerning studies by comparing different approaches using serum and inflammatory markers for muscle and soft tissue damage.

Methods:

We searched the PubMed database in the English language systematically for clinical studies or reviews, comparing muscle damage according to serum markers between two or more approaches in primary total arthroplasty.

Results:

In total, twenty-one studies were included in this review. Although the results are controversial, it seems that MIS approaches in most of the studies were related to lower levels of inflammation markers contrasting with conventional approaches. Nevertheless, this difference in muscle damage is not correlated with a difference in functional scores or other perioperative data and clinical outcomes in all studies.

Conclusion:

The existing literature does not lead to a safe consensus about the superiority of any approach. Therefore, there is still a need for further research with well-designed studies.
Energy Cost and Energy Sources of an Elite Female Soccer Player to Repeated Sprint Ability Test: A Case Study
Authors: Perroni Fabrizio , Emerenziani Gian Pietro , Pentenè Fabrizio , Gallotta Maria Chiara , Guidetti Laura , Baldari Carlo
Published: April 2019

Background:

Intense physical efforts performed at maximal or near-maximal speeds and the ability to recover among sprint are important characteristics of a soccer player. In the last years, women's soccer has become a rapidly and markedly growing sport (+34% of new players from 2000).

Objective:

The aim of this case study was to analyse the performance (total time –TT; fatigue index percentage -IF%) and physiological (aerobic and anaerobic) responses to Repeated Sprint Ability test (RSAt) of an elite female player.

Methods:

To identify the contribution of the 3 energy sources at the beginning, middle, and at the end of the different sprint of RSAt performance in a female player (age: 30 years; BMI: 20.3 kg/m2), which requested 7x30 m sprints (25 s active recovery among sprints) with a change of direction, a portable metabolimeter and software dedicated were used. A repeated measure MANOVA over the 7 sprints time series was applied (p< 0.05).

Results:

Results showed that TT was 58.71 s (Ideal Time: 56.98 s) with IF% of 3.0%. Energy contributions were given for 80.3% by aerobic, 19.2% by anaerobic lactid, and 0.5% by anaerobic alactid sources. We have found different kinetics in the heart rate (HR) and maximum oxygen uptake with the oxygen uptake that reached the peak when HR was still rising.

Conclusion:

Considering that the energy consumption during intermittent exercises requires different metabolism as a result of physiological stimuli proposed, the present findings substantiate the need to choose specific and adequate training methods for female soccer players that aim at increasing their RSA performances.
Pemetaan kompetensi teknologi informasi dan komunikasi (TIK) guru pada dimensi pedagogik
Authors: Herliani An an , Wahyudin Dinn
Published: April 2019

Kompetensi TIK diharapkan dapat menjadi penopang bagi peningkatan kompetensi pedagogik dan profesional bagi seorang guru. Kajian ini bertujuan untuk mengembangkan kompetensi TIK guru pada dimensi pedagogik yang dapat dijadikan rujukan dalam perancangan program peningkatan kompetensi guru oleh lembaga penyelenggara pendidikan dan pelatihan. Melalui pendekatan Penelitian Desain dan Pengembangan (Design and Development Research) dengan merujuk pada kerangka kerja kompetensi TIK untuk guru yang dikembangkan oleh UNESCO (UNESCO ICT Competency Framework for Teachers). Hasil penelitian telah memetakan kompetensi TIK yang dapat dicapai oleh guru melalui Pengembangan Keprofesian Berkelanjutan secara berjenjang dalam tiga level kompetensi yang dilengkapi dengan deskripsi kompetensi pada setiap levelnya.
Significance of Mitral M-Mode Vp (Velocity Propagation) for Estimating Mitral Valve Area and Severity in Mitral Stenosis
Authors: Napitupulu Bertha Gabriela , Hasan Harris
Published: April 2019

Background: Confirming mitral valve area (MVA) by planimetry is one of the standard procedures for assessing mitral stenosis but MVA were frequently need to be confirmed by other echocardiography parameters that only available in sophisticated centers. Our aim was to evaluate the significance of a simple mitral inflow color M-mode velocity propagation (Vp) for estimating MVA and MS severity.Methods: The best color view of MS jet were taken from apical 4 chamber, the nyquist limit were adjusted for aliasing the central highest velocity, then M-mode were applied to MV to calculate Vp by measuring the slope of the blue jet with the first aliasing velocity. MVA,PHT and mean transmitral gradient were analyzed with Pearson correlation and linear regression. Predictive discrimination value of Vp were analyzed by ROC.Results: Thirty one MS patients had mean MVA planimetry 0.99 ± 0.35 cm2 and mean Vp 64.49 ± 21.63 cm/s. Vp that were found to have a strong negative correlation with MVA (Spearman rho -0.865, p < 0.01). Vp had a good predictive discrimination value as from AUC 0.931. Vp were found to have a moderate correlation with MVA by PHT ( Spearman rho -0.621, p <0.01). Vp more than 55 cm/s had 93.8% sensitivity and 86.7% specificity to distinguish severe MS.Conclusions: By making use of the high temporal resolution of M-mode, a simple color Mitral M-Mode Vp were found statistically significant for estimating MVA severity in MS. Interventional decision for MS could also consider Vp for its strong correlation with MVA on MS, especially for helping on targeting moderate to severe MS in rural and limited centers.