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On the prediction of filtration volume of drilling fluids containing different types of nanoparticles by ELM and PSO-LSSVM based models

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Petroleum 2022年第3期8卷 424-435页

作者： aleksander Lekomtsev Amin Keykhosravi Mehdi Bahari Moghaddam Reza Daneshfar Omid Rezvanjou Department of Oil and Gas Technologies Perm National Research Polytechnic UniversityPerm KraiRussia Faculty of Petroleum and Natural Gas Engineering Sahand University of TechnologyTabrizIran Department of Petroleum Engineering Ahwaz Faculty of Petroleum EngineeringPetroleum University of Technology(PUT)AhwazIran

There is a direct link between the extent of formation damage and the filtration volume of the drilling fluids in hydrocarbon *** filtration volume can be diminished by adding different additives to the drilling ***,nanoparticles have been extensively used for enhancing the filtration characteristics of the drilling ***,there is no reliable model for investigating the influence of this class of additives on the performance of drilling *** in this study,two powerful tools ELM(extreme learning machine)and PSO-LSSVM(particle swarm optimization-least square support vector machine)are applied to determine the effect of various nanoparticles on the filtration *** assessment of the models is carried out by computing the statistical parameters,and it is found that ELM has a greater ability to predict the filtration volumes,while PSO-LSSVM performs satisfactorily *** model predictions and experimental results are in excellent agreement as suggested by the values of root mean squared error(RMSE=0.2459),coefficient of determination(R^(2)=0.999),and mean relative error(MRE=2.028%)for the *** statistical analysis shows that the suggested model can predict the filtration volume with great ***,through sensitivity analysis of the input parameters,it is found that for a specified nanoparticle,the filtration volume is highly influenced by nanoparticle concentration and it is the essential variable for the optimization process.

关键词： Nanoparticles Drilling mud Extreme learning machine Filtration volume Least square support vector machine

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Strain and Temperature Characterization of LPGs Written by CO2 Laser in Pure Silica LMA Photonic Crystal Fibers

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Photonic Sensors 2015年第3期5卷 241-250页

作者： Roberta Cardoso CHAVES Alexandre de Almeida Prado POHL Ilda ABE Renan SEBEM aleksander PATERNO Laboratorio Avangado de Telecomunicacoes Federal University of Technology Parancl Brazil Laboratorio de Fot6nica Federal University of Technology Parana Brazil Laboratory of Optoeleetronic Systems Santa Catarina State University Santa Catarina Brazil

This paper reports on the writing of long period gratings （LPGs） in a six-ring pure silica solid core, and large mode area photonic crystal fiber （fiber core diameter p = 10.1 μm） using a CO2 laser system, and the characterization of their strain and temperature sensitivities. Temperature and strain sensitivities in the order of-19.6pm/℃ and -88 pm/με, respectively, were obtained, which were comparable or surpassed values of the similar photonic crystal fiber （PCF）-based LPG or sensor configurations found in the literature.

关键词： Long period grating photonic crystal fiber CO2 laser

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A fuzzy formal concept analysis based approach for business component identification

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第9期12卷 707-720页

作者： Zhen-gong CAI Xiao-hu YANG Xin-yu WANG aleksander J. KAVS School of Computer Science and Technology Zhejiang University Hangzhou 310027 China StateStreet Corporation Boston MA 02111 USA

Identifying business components is the basis of component-based software engineering. Many approaches, including cluster analysis and concept analysis, have been proposed to identify components from business models. These approaches classify business elements into a set of components by analyzing their properties. However, most of them do not consider the difference in their properties for the business elements, which may decrease the ac- curacy of the identification results. Fhrthermore, component identification by partitioning business elements cannot reflect which features are responsible for the generation of certain results. This paper deals with a new approach for component identification from business models using fuzzy formal concept analysis. First, the membership between business elements and their properties is quantified and transformed into a fuzzy formal context, from which the concept lattice is built using a refined incremental algorithm. Then the components are selected from the concepts according to the concept dispersion and distance. Finally, the effectiveness and efficiency are validated by applying our approach in the real-life cases and experiments.

关键词： Business component identification Formal concept analysis Business model Concept clustering Fhzzy concept

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Safety and efficacy of Profermin~to induce remission in ulcerative colitis

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World Journal of Gastroenterology 2012年第15期18卷 1773-1780页

作者： aleksander Krag Hans Israelsen Bjrn von Ryberg Klaus K Andersen Flemming Bendtsen Gastrounit Medical Devision 360Copenhagen University Hospital Hvidovre Faculty of Health Sciences Copenhagen UniversityDK-2650 HvidovreDenmark Nordisk Rebalance A/S M.D.Madsensvej 14-16DK-3450 AllerdDenmark Statistics Section Informatics and Mathematical ModellingTechnical University of DenmarkDK-2800 LyngbyDenmark

AIM:To test the efficacy and safety of Profermin in inducing remission in patients with active ulcerative colitis(UC).METHODS:The study included 39 patients with mild to moderate UC defined as a Simple Clinical Colitis Activity Index(SCCAI)>4 and<12(median:7.5),who were treated open-label with Profermintwice daily for 24 *** SCCAI was reported observer blinded via the ***:In an intention to treat(ITT)analysis,the mean reduction in SCCAI score was 56.5%.Of the 39 patients,24(62%)reached the primary endpoint,which was proportion of patients with≥50%reduction in *** secondary endpoint,the proportion of patients in remission defined as SCCAI≤2.5,was in ITT analysis reached in 18 of the 39 patients(46%).In a repeated-measure regression analysis,the estimated mean reduction in score was 5.0 points(95%CI:4.1-5.9,P<0.001)and the estimated mean time taken to obtain half the reduction in score was 28 d(95%CI:26-30).There were no serious adverse events(AEs)or withdrawals due to *** was generally well ***:Profermin is safe and may be effective in inducing remission of active UC.

关键词： Ulcerative colitis Diet Probiotic Profermin Inflammatory bowel disease Dietary management Medical foods

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Chemistry and particle size distribution of respirable coal dust in underground mines in Central Eastern Europe

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International Journal of Coal Science & Technology 2022年第1期9卷 200-216页

作者： Pedro Trechera Xavier Querol Robert Lah Diane Johnson aleksander Wrana Ben Williamson Teresa Moreno Instituto de Diagnostico Ambiental Y Estudios del Agua Consejo Superior de Investigaciones Cientificas(IDAEACSIC)C/Jordi Girona 18‑2608034 BarcelonaSpain Department of Natural Resources and Environment Industrial and TIC Engineering(EMIT-UPC)08242 ManresaSpain Premogovnik Velenje d.d Partizanskacesta 783320 VelenjeSlovenia Camborne School of Mines University of ExeterPenrynCornwall TR109FEUK Department of Extraction Technology and Mining Support Central Mining Institute(GIG)40‑166 KatowicePlacGwarkow 1Poland

Despite international efforts to limit worker exposure to coal dust,it continues to impact the health of thousands of miners across *** coal dust has been studied to improve risk models and its control to protect *** size distribution analyses shows that using spraying systems to suppress airborne dusts can reduce particulate matter concentrations and that coals with higher ash yields produce finer *** are marked chemical differences between parent coals and relatively coarse deposited dusts(up to _(500)μm,DD_(500)).Enrichments in Ca,K,Ba,Se,Pb,Cr,Mo,Ni and especially As,Sn,Cu,Zn and Sb in the finest respirable dust fractions could originate from:(i)mechanical machinery wear;(ii)variations in coal mineralogy;(iii)coal fly ash used in shotcrete,and carbonates used to reduce the risk of *** enrichments in Ca in mine dusts are attributed to the use of such concrete,and elevated K to raised levels of phyllosilicate mineral *** concentrations are higher in the parent coal than in the DD_(500),probably due to relatively lower levels of organic *** concentrations of all elements observed in this study remained below occupational exposure limits.

关键词： Coal dust Deposited dust Respirable dust Particle size distribution Dust chemistry PM10 coal dust exposure

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Gene-environment interaction and male reproductive function

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Asian Journal of Andrology 2010年第3期12卷 298-307,I0007页

作者： Jonatan Axelsson Jens Peter Bonde Yvonne L. Giwercman Lars Rylander aleksander Giwercman Reproductive Medicine Centre Skane University Hospital Malmo 20502 Sweden Division of Occupational and Environmental Medicine Lund University Lund 22185 Sweden Department of Occupational Medicine Copenhagen University Bispebjerg Hospital Copenhagen NV2400 Denmark Department of Clinical Sctences Malmo Lund University Malmo 20502 Sweden

As genetic factors can hardly explain the changes taking place during short time spans, environmental and lifestyle-related factors have been suggested as the causes of time-related deterioration of male reproductive function. However, considering the strong heterogeneity of male fecundity between and within populations, genetic variants might be important determinants of the individual susceptibility to the adverse effects of environment or lifestyle. Although the possible mechanisms of such interplay in relation to the reproductive system are largely unknown, some recent studies have indicated that specific genotypes may confer a larger risk of male reproductive disorders following certain exposures. This paper presents a critical review of animal and human evidence on how genes may modify environmental effects on male reproductive function. Some examples have been found that support this mechanism, but the number of studies is still limited. This type of interaction studies may improve our understanding of normal physiology and help us to identify the risk factors to male reproductive malfunction. We also shortly discuss other aspects of gene-environment interaction specifically associated with the issue of reproduction, namely environmental and lifestyle factors as the cause of sperm DNA damage. It remains to be investigated to what extent such genetic changes, by natural conception or through the use of assisted reproductive techniques, are transmitted to the next generation, thereby causing increased morbidity in the offspring.

关键词： endocrine disruption gene-environment interaction persistent organic pollutants semen quality testicular cancer

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Vlale patients with terminal renal failure exhibit low serum levels of antimullerian hormone

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Asian Journal of Andrology 2015年第1期17卷 149-153,I0012页

作者： Dag Eckersten aleksander Giwercman Anders Christensson Department of Nephrology and Transplantation Reproductive Medicine Centre Lund University Skane University Hospital Malmo Sweden.

Male reproductive function is impaired during end-stage renal disease （ESRD）. Disturbance of the hypothalamic-pituitary-gonadal axis, and therefore the regulation of sex hormones, is one of the major causes. Our focus was to include antimLillerian hormone （AMH） and inhibin B concentrations. Twenty male patients on hemodialysis, median age 40 （26-48） years, were analyzed for follicle-stimulating hormone （FSH）, luteinizing hormone （LH）, prolactin, sex hormone-binding globulin （SHBG）, testosterone, estradiol, AMH and inhibin B levels. We used 144 proven fertile men, median age 32 （19-44） years as a control group and analyzed differences using multiple linear regression. Males with ESRD demonstrated higher mean values for prolactin, 742 versus normal 210 mlE 1-1 （95% confidence interval （Cl）： 60.3, 729）, LH, 8.87 versus normal 4.5 IE 1-1 （95% Ch 2.75, 6.14）, and estradiol 89.7 versus normal 79.0 pmol 1-1 （95% CI： -1.31, -0.15）. Mean value for AMH was lower, 19.5 versus normal 47.3 pmol 1-1 （95% Cl. -37.6, -11.6）. There were no differences found for FSH, SHBG, inhibin B and testosterone. The most important difference was found for AMH, a marker of Sertoli cell function in the testes, which decreased by close to 60% when compared with controls. Combined with an increase in LH, these findings may indicate a dysfunction of Sertoli cells and an effect on Leydig cells contributing to a potential mechanism of reproductive dysfunction in men with ESRD.

关键词： antimOIlerian hormone chronic kidney disease end-stage renal disease infertility inhibin B sex hormones

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Design and guidance of a multi-active debris removal mission

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Astrodynamics 2023年第4期7卷 383-399页

作者： Minduli C.Wijayatunga(B) Roberto Armellin Harry Holt Laura Pirovano aleksander A.Lidtke Te Pūnaha Atea–Space Institute The University of AucklandAuckland 1010New Zealand Astroscale Japan Inc. 1-16-4-16 KinshiSumida-kuTokyoJapan

Space debris have become exceedingly dangerous over the years as the number of objects in orbit continues to *** debris removal(ADR)missions have gained significant interest as effective means of mitigating the risk of collision between objects in *** study focuses on developing a multi-ADR mission that utilizes controlled reentry and *** mission comprises two spacecraft:a Servicer that brings debris to a low altitude and a Shepherd that rendezvous with the debris to later perform a controlled reentry.A preliminary mission design tool(PMDT)was developed to obtain time and fuel optimal trajectories for the proposed mission while considering the effect of J2,drag,eclipses,and duty *** PMDT can perform such trajectory optimizations for multi-debris missions with computational time under a *** guidance schemes are also studied,taking the PMDT solution as a reference to validate the design methodology and provide guidance solutions to this complex mission profile.

关键词： active debris removal(ADR) trajectory design optimization autonomous guidance low-thrust electric propulsion △u-law guidance Q-law guidance

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Laboratory pull-out tests on fully grouted rock bolts and cable bolts:Results and lessons learned

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第5期9卷 843-855页

作者： Isabelle Thenevin Laura Blanco-Martín Faouzi Hadj-Hassen Jacques Schleifer Zbigniew Lubosik aleksander Wrana MINES ParisTech Department of Geosciences PSL Research University 35 rue Saint Honoré Fontainebleau Cedex 77305 France Department of Extraction Technology and Mining Support Central Mining Institute (GIG) Katowice Poland

Laboratory pull-out tests were conducted on the following rock bolts and cable bolts:steel rebars,smooth steel bars,fiberglass reinforced polymer threaded bolts,flexible cable bolts,IR5/IN special cable bolts and Mini-cage cable *** diameter of the tested bolts was between 16 mm and 26 *** bolts were grouted in a sandstone sample using resin or cement *** tests were conducted under either constant radial stiffness or constant confining pressure boundary conditions applied on the outer surface of the rock *** most tests,the rate of displacement was about 0.02 mm/*** tests were performed using a pull-out bench that allows testing a wide range of *** paper provides an extensive database of laboratory pull-out test results and confirms the influence of the confining pressure and the embedment length on the pull-out response(rock bolts and cable bolts).It also highlights the sensitivity of the results to the operating conditions and to the behavior of the sample as a whole,which cannot be neglected when the test results are used to assess the bolt-grout or the grouterock interface.

关键词： Pull-out test Fully grouted bolts Laboratory-scale Confining pressure Embedment length Bolt-grout interface

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Postoperative negative-pressure drainage through a PEG tube can prevent pancreatic fistula after pancreatoduodenectomy

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Hepatobiliary & Pancreatic Diseases International 2020年第1期19卷 85-87页

作者： aleksander Sowier Przemysław Pyd Sebastian Sowier Joanna Kapturzak Anna Rybak Jacek Bialecki Department of General Minimally Invasive and Trauma SurgeryFranciszek Raszeja City Hospital in Poznanul.Mickiewicza 260-834 PoznanPoland Department of General and Endocrine Surgery and Gastroenterological Oncology Poznan University of Medical Sciencesul.Przybyszewskiego 4960-355 PoznanPoland

Postoperative pancreatic fistula(POPF)is a well-known complication after pancreatoduodenectomy[1].It is difficult to prevent due to a number of *** very placement and tightening of sutures in pancreatic tissue is *** of the anastomosis edges is *** risk factor is the large amounts of fluids(comprising gastric and intestinal secretions,bile,and pancreatic juice)collected in the intestine near the pancreatic anastomosis,which increase the pressure in the first loop of the anastomosed intestine,and may ultimately rupture the pancreatoenteric *** peristalsis,required to pass these fluids to subsequent sections of the intestine,takes time to return after such an extensive *** pressure in the intestinal loop may also contribute to ischemia,by increasing the tension of the intestinal wall,constricting or even blocking its blood *** these are aggravated by the chemical effects of intestinal *** surgical errors may add the risk of POPF.

关键词： intestine fistula return

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