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Modeling of fiber bridging in fluid flow for well stimulation applications

Petroleum Science 2020年第3期17卷 671-686页

作者： Mehdi Ghommem Mustapha Abbad Gallyam Aidagulov Steve Dyer dominic Brady Department of Mechanical Engineering American University of ShaijahSharjah 26666United Arab Emirates Schlumberger Dhahran Carbonate Research Center Dammam/Doha Camp 31942Kingdom of Saudi Arabia Schlumberger Completions RosharonTX 77583USA

Accurate acid placement constitutes a major concern in matrix stimulation because the acid tends to penetrate the zones of least resistance while leaving the low-permeability regions of the formation *** materials(fibers and solid particles)have recently shown a good capability as fluid diversion to overcome the issues related to matrix *** the success achieved in the recent acid stimulation jobs stemming from the use of some products that rely on fiber flocculation as the main diverting mechanism,it was observed that the volume of the base fluid and the loading of the particles are not *** current industry lacks a scientific design guideline because the used methodology is based on experience or empirical studies in a particular area with a particular *** is important then to understand the fundamentals of how acid diversion works in carbonates with different diverting mechanisms and *** modeling and computer simulations are effective tools to develop this understanding and are efficiently applied to new product development,new applications of existing products or usage *** this work,we develop a numerical model to study fiber dynamics in fluid *** employ a discrete element method in which the fibers are represented by multi-rigid-body systems of interconnected *** discrete fiber model is coupled with a fluid flow solver to account for the inherent simultaneous *** focus of the study is on the tendency for fibers to flocculate and bridge when interacting with suspending fluids and encountering restrictions that can be representative of fractures or wormholes in *** trends of the dynamic fiber behavior under various operating conditions including fiber loading,flow rate and fluid viscosity obtained from the numerical model show consistency with experimental *** present numerical investigation reveals that the bridging capability of the fi

关键词： Fiber bridging Fiber flocculation Modeling and numerical simulation Discrete element method Fiber-fluid coupling Sensitivity analysis

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Entropy of Quantum Dynamical Systems and Sufficient Families in Orthomodular Lattices with Bayessian State

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Communications in Theoretical Physics 2008年第9期50卷 551-556页

作者： Mona Khare Shraddha roy Department of Mathematics University of AllahabadAllahabad211 001India Allahabad Mathematical Society 10C.S.P.Singh MargAllahabad211 001India

The purpose of the present paper is to study the entropy hs（Ф） of a quantum dynamical systems Ф = （ L, s, Ф）, where s is a bayessian state on an orthomodular lattice L. Having introduced the notion of entropy hs（ Ф, A） of partition A of a Boolean algebra B with respect to a state s and a state preserving homomorphism Ф, we prove a few results on that, define the entropy of a dynamical system hs（Ф）, and show its invariance. The concept of sufficient families is also given and we establish that hs （Ф） comes out to be equal to the supremum of hs （Ф,A）, where A varies over any sufficient family. The present theory has then been extended to the quantum dynamical system （ L, s, Ф）, which as an effect of the theory of commutators and Bell inequalities can equivalently be replaced by the dynamical system （B, s0, Ф）, where B is a Boolean algebra and so is a state on B.

关键词： orthomodular lattices quantum logic valuation isomorphism partitions entropy quantum dynamical systems sufficient families

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How can the forest sector mitigate climate change in a changing climate? Case studies of boreal and northern temperate forests in eastern Canada

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Forest Ecosystems 2022年第2期9卷 267-287页

作者： Lucas Moreau Evelyne Thiffault dominic Cyr Yan Boulanger Robert Beauregard Departement des sciences du bois et de la foret Universite LavalQuebecCanada Science and Technology Branch Environment and Climate Change CanadaGatineauCanada Laurentian Forestry Centre Natural Resources CanadaQuebecCanada

Background:Forest based climate mitigation emerged as a key component of the Paris Agreement,and thus re-quires robust science to reduce uncertainties related to such *** aim of this study was to assess and compare the cumulative effects on carbon dynamics of forest management and climate change on boreal and northern temperate forest sector in eastern Canada for the 2020–2100 ***:We used the spatially explicit forest landscape model LANDIS-II and its extension Forest Carbon Suc-cession,in conjunction with the Carbon Budget Model for Harvested Wood Products *** simulated the dynamics of forest composition and carbon flows from forest ecosystems to wood products and their substitution effect on markets under increasing climate forcing,according to a tonne-year *** were con-ducted for a series of forest management scenarios based on realistic practices principally by clearcut in the boreal territory and continuous-cover forestry in the northern temperate *** scenarios included:i)a business-as-usual scenario(BaU),representing the current management strategy,ii)increased harvesting by 6.3%to 13.9%,iii)increased conservation(*** harvesting by 11.1%to 49.8%),iiii)and a scenario representing the natural evolution of the forest landscape(*** any management activity).Results:Our study revealed that increasing harvesting levels had contrasting effects on the mitigation potential in northern temperate(enhance net sequestration)and boreal forest sector(enhance net emissions)in comparison to the BaU from 2040 onwards,regardless of the future *** storage in wood products and the substi-tution effect were not sufficient to offset carbon emissions from ***,climate change had a strong impact on the capacity of both landscapes to act as carbon *** temperate landscapes became a net source of carbon over time due to their greater vulnerability to climate change than boreal landsc

关键词： Climate change Carbon Forest sector Forest management Boreal landscapes Northern temperate landscape Mitigation potential

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Computational investigation of hydraulic performance variation with geometry in gabion stepped spillways

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Water Science and Engineering 2019年第1期12卷 62-72页

作者： dominic E.Reeve Ali Adel Zuhaira Harshinie Karunarathna College of Engineering Swansea University

Over recent years, there has been a clear increase in the frequency of reported flooding events around the world. Gabion structures offer one means of flood mitigation in dam spillways. These types of structures provide an additional challenge to the computational modeller in that flow through the porous gabions must be simulated. We have used a computational model to investigate the flow over gabion stepped spillways. The model was first validated against published experimental results. Then, gabion stepped spillways with four different step geometries were tested under the same conditions in order to facilitate inter-comparisons and to choose the best option in terms of energy dissipation. The results show that normal gabion steps can dissipate more energy than overlap, inclined, and pooled steps. An intensive set of tests with varying slope, stone size, and porosity were undertaken. The location of the inception point and the water depth at this point obtained from this study were compared with those from existing formulae. Two new empirical equations have been derived, on the basis of a regression analysis, to provide improved results for gabion stepped spillways.

关键词： Computational modelling Energy dissipation Gabion stepped spillways Inception point location Skimming flow

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Changes in electrical conductivity of liquid foods during ohmic heating

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International Journal of Agricultural and Biological Engineering 2014年第5期7卷 133-138页

作者： Shivmurti Srivastav Srishti roy Department of Food Processing Technology A.D.Patel Institute of TechnologyNew Vallabh Vidya NagarAnandGujarat 388121India

Ohmic heating is a food processing method in which alternating current(AC)went through a food sample and resulted in internal energy generation in *** is an alternative fast heating *** principal advantage is the ability to rapidly and uniformly heat food materials of various *** ohmic heating,change in electrical conductivity was *** intensity of food materials’electrical conductivity or overall resistance critically controls ohmic heating *** ohmic heating set-up was prepared under this *** juice was heated(about 32℃ to 80℃)in a batch type ohmic heater at different voltage gradients in the range of 50-70 V/*** was statistically found that the voltage gradient had significant impact on conductivity and system performance coefficient(SPC)(P<0.05).It was concluded that the electrical conductivity values linearly increased with *** SPCs of the system ranged between 0.779 and *** value of R2 of the linear model was greater than 0.98.

关键词： ohmic heating electrical conductivity thermal conductivity liquid foods

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Awareness,practice and views about integrating AYUSH in allopathic curriculum of allopathic doctors and interns in a tertiary care teaching hospital in New Delhi,India

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Journal of Integrative Medicine 2018年第2期16卷 113-119页

作者： Shubha Singhal Vandana roy Department of Pharmacology Maulana Azad Medical College

Objective： To assess the knowledge, attitude, perception and practice of Ayurveda, yoga, Unani, Siddha, homeopathy and naturopathy （AYUSH） among allopathic doctors and interns and determine their opin- ion regarding integration of AYUSH education within the allopathic curriculum. Methods： This prospective, cross sectional study was conducted in a tertiary care teaching Hospital, New Delhi, India, from March 2016 to March 2017. A survey of 500 aUopathic doctors and 150 interns was performed using a structured questionnaire. Results： A majority of doctors （95.2%） were aware of the term AYUSH and had knowledge of yoga （70.6%）, homeopathy （55.6%）, Ayurveda （50.3%）, Siddha （47.8%）, naturopathy （32.9%） and Unani （28.9%）. Most of the participants （63.0%） felt that therapies under AYUSH are effective. A majority （84.0%） of the doctors were of the view that more research is required in the field of AYUSH. While homeopathy （44.0%） was the most common system used by doctors for themselves, yoga was the therapy most commonly （60.0%） recommended to patients. Nearly half of the doctors （46.7%） recommended AYUSH to their patients, mainly for chronic illness （74.0%）. A majority （77.5%） of the respondents agreed that students of allopathic med- icine should be familiarized with AYUSH. The modes of incorporation of AYUSH into the medical curriculum most commonly suggested by respondents were optional courses （54.5%） and introductory lectures （42.3%）. Conclusion： Doctors and interns ofallopathic medicine are aware of AYUSH systems. They use it for them- selves and recommend it to patients. They believe that familiarization of Bachelor of Medicine and Bachelor of Surgery students with AYUSH therapies and their integration with allopathic medicine may help in improving patient care.

关键词： Ayurveda Yoga Unani Siddha Homeopathy Naturopathy Allopathic doctors Complementary therapies Ayurvedic medicine

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Time variant multi-objective linear fractional interval-valued transportation problem

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Applied Mathematics(A Journal of Chinese Universities) 2022年第1期37卷 111-130页

作者： Dharmadas Mardanya Sankar Kumar roy Department of Applied Mathematics with Oceanology and Computer Programming Vidyasagar UniversityMidnapore 721102West BengalIndia

This paper studies a time-variant multi-objective linear fractional transportation problem. In reality, transported goods should reach in destinations within a specific time. Considering the importance of time, a time-variant multi-objective linear fractional transportation problem is formulated here. We take into account the parameters as cost, supply and demand are interval valued that involved in the proposed model, so we treat the model as a multi-objective linear fractional interval transportation problem. To solve the formulated model, we first convert it into a deterministic form using a new transformation technique and then apply fuzzy programming to solve it. The applicability of our proposed method is shown by considering two numerical examples. At last, conclusions and future research directions regarding our study is included.

关键词： fractional transportation problem multi-objective optimization interval number time variant parameter fuzzy programming Pareto optimal solution

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Charge transport in monolayer poly(3-hexylthiophene) thin-film transistors

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Chinese Physics B 2014年第4期23卷 700-703页

作者：许宗祥 roy V.A.L Department of Chemistry South University of Science and Technology of China Center Of Superdiamond and Advanced Films (COSDAF) Department of Physics and Materials ScienceCity University of Hong Kong

It is found that ultrathin poly（3-hexylthiophene）（P3HT） film with a 2.5 nm-thick layer exhibits a higher mobility of 5.0× 10-2 cm2/V-s than its bulk counterpart. The crystalline structure of the as-fabricated ultrathin P3HT layer is verified by atomic force microscopy as well as grazing incidence X-ray diffraction. Transient measurements of the as-fabricated transistors reveal the influence of the interface traps on charge transport. These results are explained by the trap energy level distribution at the interface manipulated by layers of polymer film.

关键词： field-effect transistor monolayer P3HT spin coating grazing incidence X-ray diffraction

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Performance Prediction of a Multi-Stage Wind Tower for Indoor Cooling

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Journal of Thermal Science 2012年第4期21卷 327-335页

作者： roy J. Issa Byungik Chang Department of Engineering and Computer Science West Texas A&M University Canyon

A theoretical model is developed to establish an indepth understanding of the performance of a three-stage wind tower with a bypass system for indoor cooling in rural dry and hot climates. Model simulations are presented for a wide range of ambient conditions that include inlet wind speed, inlet temperature and relative humidity. Simulation results provide an insight into the desirable water flow rates and air-to-water loadings for comfort zone tem-peratures and relative humidity levels at the exit of the wind tower. Simulations show wind towers with variable cross-sections provide an increase in the cooling power for the same inlet wind speed, inlet air temperature and relative humidity when compared to wind towers with a constant cross-section. The study shall lead to a better understanding to designing wind towers that are both environmentally friendly and energy efficient.

关键词： Wind tower Cooling power Cooling effectiveness Relative humidity

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High-speed wind tunnel test of the CAE aerodynamic validation model

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Chinese Journal of Aeronautics 2018年第3期31卷 439-447页

作者： roy GEBBINK Ganglin WANG Min ZHONG German-Dutch Wind Tunnels Marknesse 8316 PR The Netherlands Chinese Aeronautical Establishment Beijing 100012 China

For the purpose of establishing and validating aerodynamic performance predictions at transonic Mach numbers, a wind tunnel test was conducted in the High-Speed Tunnel（HST） of the German-Dutch Wind Tunnels. The test article is the aerodynamic validation model from the Chinese Aeronautical Establishment, which is a full-span scale model representation of a business jet aircraft. The wind tunnel test comprised of parallel deployments of balance, pressures, infrared thermography, and model marker measurement techniques. Dedicated investigations with a dummy support were conducted as well, in order to derive and correct for the interference that the support system imposed on the overall model loads. This enabled the establishment of a comprehensive dataset in which the steady overall model loads, the wing load distribution, the state of the wing boundary layer, and the aeroelastic wing shape were quantified for conditions up to and beyond the cruise Mach number of 0.85.

关键词： Wind tunnel test Aerodynamic validation model Model deformation Support interference

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