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3D modeling of abnormal pore pressure in shallow offshore Niger delta: An application of seismic inversion

Petroleum Research 2021年第2期6卷 158-171页

作者： Chukwuemeka patrick Abbey Osita Chukwudi meludu Adetola Sunday Oniku a a Department of Physics Modibbo Adama University of Technology YolaNigeria Department of Petroleum Chemistry&Physics American University of NigeriaNigeria

Pore pressure is the pressure associated with fluids in the pore spaces of sedimentary rocks. Thispressure varies from hydrostatic to severe overpressure. It is classified as abnormal pressure when itdeviates from hydrostatic pressure. Incorrect prediction or the absence of pore pressure evaluation canlead to severe damage of the drilling platform, loss of personnel, waste of resources and environmentalpollution. This study was carried out in an offshore field in Niger Delta with an objective of predicting theabnormal pressure regime from the seismic volume using seismic inversion technique. First, weemployed the Eaton’s and Bower’s model of predicting pore pressure from Well log. The predicted porepressure from the well was used to calibrate the P-impedance that was used in the inversion process. Apressure-based model for the seismic inversion process was developed. This was constrained by therelationship between the P-impedance and pore pressure in the study area. The predicted pore pressurefrom the Well logs aligned with the measured pore pressure in the formation. At about 3600 m to end ofthe Well, depicts a pressure regime that is a deviation from the hydrostatic pressure trend. The abnormalpressure regime is marked by the region where a change is observed in the normal compaction trendline. The cross plot of acoustic impedance against pore pressure reveals a linear relationship;with adirect relationship indicating a normal pressure interval and the indirect relationship at the abnormalpressure regime. The inverted 3D pressure result from the seismic volume validates the normalcompaction trend line and also the pressure values estimated from the Well logs. The abnormal pressureregime in the study area is predicted to be found towards the end of Agbada Formation and through theAkata Formation due to the un-compacted shales.

关键词： Acoustic impedance Pressure Seismic inversion Formation Overpressure

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Geotechnical behavior of uranium mill tailings from Saskatchewan,Canada

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International Journal of mining Science and Technology 2016年第3期26卷 369-375页

作者： Bhuiyan Imteaz Azam Shahid Khaled Shifullah Landine patrick Environmental Systems Engineering University of Regina Thurber Engineering Limited Cameco Corporation

This paper investigates the geotechnical behavior of uranium mill tailings from Saskatchewan, *** 4% tailings were well-graded with 29% fines whereas the 5% and 6% tailings were gap-graded with 49% fines. All samples exhibited a negligible strength(0.4 k Pa) up to 60% solids, followed by a rapid increase. The 4% tailings exhibited a lower rate and amount of settlement than 5% and 6% tailings. The kidecreased from 10^(-2)to 10^(-4)m/s with a decrease in eifrom 16 to 4 and a decrease in ef from 8 to 4 such that 4% tailings showed one order of magnitude lower values than the 5% and 6%tailings. The settling potential decreased ten times(50%–5%) for 4% tailings and four times(60%–15%)for 5% and 6% tailings. The effective stress increased from 80 to 260 Pa in the settling tests. The 4%tailings were less prone to segregation when compared with 5% and 6% tailings. The average solids content after settling was 35% for 4% tailings, 40% for 5% tailings and 39% for 6% tailings with a solids content deviation of ±3%, ±8%, ±6%, respectively. All materials were essentially non-segregating at 40%initial solids.

关键词： Uranium mill tailings Rheology Settling Segregation

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Synthesis and characterization of Ce_(0.6)Sr_(0.4)Fe_(0.8)Co_(0.2)O_(3–δ) perovskite material:Potential cathode material for low temperature SOFCs

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Journal of Rare Earths 2017年第4期35卷 389-397页

作者： mlungisi N.Sithole Bernard Omondi patrick G.Ndungu School of Chemistry and Physics University of KwaZulu-NatalWestville CampusPrivate Bag X54001Durban4000South Afrzca Department of Applied Chemistry Doornfontein Campus University of JohannesburgP.O.Box 1701 lDoornfontein 2028JohannesburgSouth.Africa

A sol-gel method and a modified chemical vapour deposition technique were used to produce nanostructured Ce0.6Sr0.4Fe0.8Co0.2O3-δ materials at temperatures as low as 400 ℃. Powders were characterized using Fourier transform infrared spectroscopy （FTIR）, Raman spectroscopy, thermo gravimetric analysis, powder X-ray diffraction （XRD）, scanning electron microscopy （SEm） with energy dispersive X-ray spectroscopy, high resolution transmission electron microscopy （HRTEm）, and nitrogen sorption at 77 K. FTIR spectra showed that the sol-gel method resulted in residual carbon groups on the materials after calcination, while the Raman and XRD analysis confirmed that both synthesis methods resulted in cubic perovskite structure. However, the chemical va- pour deposition （CVD） method resulted in materials with a smaller crystallite size when compared to those prepared via the sol-gel route. The overall morphology of the powders was irregularly shaped aggregated particles as observed by SEm and HRTEm. In addition, HRTEm analysis showed that the materials were highly crystalline. Textural analysis revealed the powders had some mesoporosity, and the surface areas were 76.69 and 65.90 m2/g for materials synthesized using the CVD and sol-gel methods, respectively. The synthesized perovskite powders were used to fabricate button cells employing samarium doped ceria （SDC） as the electrolyte and NiO/SDC as the anode materials. As cathode materials, the maximum power density observed was 308.4 mW/cm2 at 500℃.

关键词： nanostructured materials low temperature SOFCs perovskites ceria rare earths

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Gas flow in rotary kilns

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Particuology 2010年第6期8卷 613-616页

作者： patrick R.Davies michael J.S.Norton D.Ian Wilson John F.Davidson David m.Scott Department of Chemical Engineering and Biotechnology University of CambridgePembroke StreetCambridgeCB2 3RAUK

This paper describes an experimental investigation on the flow characteristics within a rotating cylinder containing a rolling bed of sand. The axis of the cylinder was horizontal and there was no axial bulk flow of particles. The velocity field of the gas flowing through the cylinder was measured by hot-wire anemometry. The measurements indicate that the velocity field is asymmetric with respect to a diameter perpendicular to the granular bed. CFD calculations confirm this finding. The gas velocity profiles are crucial in determining heat transfer from gas to solid.

关键词： Rotating cylinderVelocity profile

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Physical and chemical changes of rapeseed meal proteins during toasting and their effects on in vitro digestibility

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Journal of Animal Science and Biotechnology 2017年第2期8卷 417-427页

作者： Sergio Salazar-Villanea Erik m.A.m.Bruininx Harry Gruppen Wouter H.Hendriks patrick Carré Alain Quinsac Antonius F.B.van der Poel Wageningen Livestock Research P.O.Box 3386700 AH WageningenThe Netherlands Animal Nutrition Group Wageningen University&ResearchP.O.Box 3386700 AH WageningenThe Netherlands Agfifirm Innovation Center Royal Dutch Agrifirm GroupP.O.Box 200187302 HA ApeldoornThe Netherlands Laboratory of Food Chemistry Wageningen University&ResearchP.O.Box 176700 AA WageningenThe Netherlands CREOL/OLEAD 11 rue MongeParc Industriel33600 PessacFrance Terres Inovia 11 rue MongeParc Industriel33600 PessacFrance

Background： Toasting during the production of rapeseed meal（RSm） decreases ileal crude protein（CP） and amino acid（AA） digestibility. The mechanisms that determine the decrease in digestibility have not been fully elucidated. A high protein quality, low-denatured, RSm was produced and toasted up to 120 min, with samples taken every 20 min. The aim of this study was to characterize secondary structure and chemical changes of proteins and glucosinolates occurring during toasting of RSm and the effects on its in vitro CP ***： The decrease in protein solubility and the increase of intermolecular β-sheets with increasing toasting time were indications of protein aggregation. The contents of NDF and ADIN increased with increasing toasting *** of arginine, lysine and O-methylisourea reactive lysine（OmIU-RL） linearly decreased with increasing toasting time, with a larger decrease of OmIU-RL than lysine. First-order reactions calculated from the measured parameters show that glucosinolates were degraded faster than lysine, OmIU-RL and arginine and that physical changes to proteins seem to occur before chemical changes during toasting. Despite the drastic physical and chemical changes noticed on the proteins, the coefficient of in vitro CP digestibility ranged from 0.776 to 0.750 and there were no effects on the extent of protein hydrolysis after 120 min. In contrast, the rate of protein hydrolysis linearly decreased with increasing toasting time, which was largely correlated to the decrease in protein solubility, lysine and OmIU-RL observed. Rate of protein hydrolysis was more than 2-fold higher for the untoasted RSm compared to the 120 min toasted ***： Increasing the toasting time for the production of RSm causes physical and chemical changes to the proteins that decrease the rate of protein hydrolysis. The observed decrease in the rate of protein hydrolysis could impact protein digestion and utilization.

关键词： Hydrolysis rate In vitro protein digestibility Rapeseed meal Reactive lysine Secondary structure

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Dynamic magnetic resonance defecography in 10 asymptomatic volunteers

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World Journal of Gastroenterology 2012年第46期18卷 6836-6842页

作者： Andreas G Schreyer Christian Paetzel Alois Fürst Lena m Dendl Elisabeth Hutzel René müller-Wille Philipp Wiggermann Stephan Schleder Christian Stroszczynski patrick Hoffstetter Department of Radiology University Medical Center Regensburg Department of Radiology Weiden Hospital Department of Surgery St. Josef Hospital

AIm: Evaluation of the wide range of normal findings in asymptomatic women undergoing dynamic magnetic resonance (mR) defecography. mETHODS: mR defecography of 10 healthy female volunteers (median age: 31 years) without previous pregnancies or history of surgery were evaluated. The rectum was filled with 180 mL gadolinium ultrasound gel mixture. mR defecography was performed in the supine position. The pelvic floor was visualized with a dynamic T2-weighted sagittal plane where all relevant pelvic floor organs were acquired during defecation. The volunteers were instructed to relax and then to perform straining maneuvers to empty the rectum. The pubococcygeal line (PCGL) was used as the line of reference. The movement of pelvic floor organs was measured as the vertical distance to this reference line. Data were recorded in the resting position as well as during the defecation process with maximal straining. Examinations were performed and evaluated by two experienced abdominal radiologists without knowledge of patient history. RESULTS: Average position of the anorectal junction was located at -5.3 mm at rest and -29.9 mm during straining. The anorectal angle widened significantly from 93° at rest to 109° during defecation. A rectocele was diagnosed in eight out of 10 volunteers showing an average diameter of 25.9 mm. The bladder base was located at a position of +23 mm at rest and descended to -8.1 mm during defecation in relation to the PCGL. The bladder base moved below the PCGL in six out of 10 volunteers, which was formally defined as a cystocele. The uterocervical junction was located at an average level of +43.1 mm at rest and at +7.9 mm during straining. The uterocervical junction of three volunteers fell below the PCGL; described formally as uterocervical prolapse. CONCLUSION: Based on the range of standard values in asymptomatic volunteers, mR defecography values for pathological changes have to be re-evaluated.

关键词： magnetic resonance imaging Defecography Standard values

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Integration of Indigenous Knowledge and Disaster Risk Reduction: A Case Study from Baie martelli, Pentecost Island, Vanuatu

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International Journal of Disaster Risk Science 2012年第4期3卷 185-194页

作者： Rory A.Walshe patrick D.Nunn Department of Geography Environment and Disaster ManagementCoventry UniversityCoventry CV15FBUnited Kingdom School of Behavioural Cognitive and Social SciencesUniversity of New EnglandArmidaleNew South Wales 2351Australia

Despite reaching heights of >6 m and destroying a sizeable coastal settlement at the head of Baie martelli(Pentecost Island, Vanuatu, South Pacific), the 26 November 1999 tsunamis caused only five fatalities from a threatened population of about 300 persons, most of whom fled inland and upslope before the waves struck. This remarkable survival rate is attributed to both indigenous knowledge, largely in the form of kastom knowledge, and information obtained from a video about tsunamis that was shown in the area three weeks earlier. Interviews with 55 persons who experienced this tsunami suggest that indigenous knowledge about tsunami risk and response in Baie martelli was well known among key members of the community and was probably largely responsible for the appropriate response. Future strategies for disaster risk reduction should involve maintaining such indigenous knowledge in such communities and supplementing this where needed with scientific knowledge filtered through indigenous culture and language.

关键词： Island cost inland

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Growth and form of Quercus robur and Fraxinus excelsior respond distinctly different to initial growing space: results from 24-year-old Nelder experiments

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Journal of Forestry Research 2013年第1期24卷 1-14页

作者： Christian Kuehne patrick Pyttel Edgar Kublin Jürgen Bauhus Institute of Silviculture University of FreiburgD-79085 Freiburg i.Br.Germany. Faculty of Forests and Forestry University of Applied Sciences Wei- henstephan-TriesdorfHans-Carl-von-Carlowitz-Platz 3D-85354 FreisingGermany Department of Biometry and Informatics Forest Research Station Baden-WürttembergPostfach 708D-79007 FreiburgGermany

Initial growing space is of critical importance to growth and quality development of individual trees. We investigated how mortality, growth （diameter at breast height, total height）, natural pruning （height to first dead and first live branch and branchiness） and stem and crown form of 24-year-old pedunculate oak （Quercus robur [L.]） and European ash （Fraxinus excelsior [L.]） were affected by initial spacing. Data were recorded from two replicate single-species Nelder wheels located in southern Germany with eight initial stocking regimes varying from 1,020 to 30,780 seedlings·ha？1. mortality substantially decreased with increasing initial growing space but significantly differed among the two species, averaging 59% and 15% for oak and ash plots, respectively. In contrast to oak, the low self-thinning rate found in the ash plots over the investigated study period resulted in a high number of smaller intermediate or suppressed trees, eventually retarding individual tree as well as overall stand development. As a result, oak gained greater stem dimensions throughout all initial spacing regimes and the average height of ash significantly increased with initial growing space. The survival of lower crown class ashes also appeared to accelerate self-pruning dynamics. In comparison to oak, we observed less dead and live primary branches as well as a smaller number of epicormic shoots along the first 6 m of the lower stem of dominant and co-dominant ashes in all spacing regimes. Whereas stem form of both species was hardly affected by initial growing space, the percentage of brushy crowns significantly increased with initial spacing in oak and ash. Our findings suggest that initial stockings of ca. 12,000 seedlings per hectare in oak and 2,500 seedlings per hectare in ash will guarantee a sufficient number of at least 300 potential crop trees per hectare in pure oak and ash plantations at the end of the self-thinning phase, respectively. If the problem of epicormic shoots a

关键词： spacing trial stocking self-thinning intraspecific competition qualification spatially explicit modelling generalized additive model

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Environmental and energy requirements for different production biomass of Nile tilapia(Oreochromis niloticus)in recirculating aquaculture systems(RAS)in Kenya

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Aquaculture and Fisheries 2021年第6期6卷 593-600页

作者： Daniel mwendwa Wambua patrick G.Home James m.Raude Stephen Ondimu Department of Soil Water and Environmental EngineeringJomo Kenyatta University of Agriculture and TechnologyP.O.BOX 62000-00200NairobiKenya Department of Agricultural and Biosystems Engineering Jomo Kenyatta University of Agriculture and TechnologyP.O.BOX 62000-00200NairobiKenya

Recirculating Aquaculture Systems(RAS)offers a better option to increase aquaculture production with limited land and water resources while minimizing water *** biggest challenges in RAS is to maintain favorable water quality for the fish to *** practice of RAS in Kenya is minimal with the improper matching of RAS components and production densities for the existing few and in most cases,leading to a system *** study aimed at evaluating environmental and energy requirements for different production biomass of Nile tilapia in a RAS established in a controlled *** production densities and water flow rates were varied while at the same time,the water quality parameters(dissolved oxygen,ammonia,pH,electrical conductivity and temperature)were *** energy consumed for pumping and aeration was also *** stocking biomass varied from 2.3 kg/m^(3) to 10 kg/m^(3) while flow rate was varied from 2.0 L/min and increased at intervals of 1.0 L/min to the maximum attainable flow rate of 10.0 L/*** pumice rock packed in a 1000 L tank and equipped with a bell siphon was used as the *** removal reduced with increasing flow rate with removal rates of 75%at 2.0-3.0 L/min to 9%at 8.0-10.0 L/*** water pH increased with increasing flow rate with R^(2) ranging from 0.4 to *** conductivity increased with flow rate from 112 mg/L to as high as 209 mg/*** oxygen increased with flow rate and ranged from 1.0 mg/L to 7.0 mg/*** consumption increased with flow rate and raged from 0.4 kW h at 2.3 kg/m^(3) stocking biomass to 2.4 kW h at 10 kg/m^(3)stocking *** stocking densities and flow rates resulted to lower purification efficiencies and higher power consumptions than low stocking densities and flow *** order to maintain good RAS water quality,increased production and profits among farmers using RAS in Kenya,there is need to give proper advice on the right combination of st

关键词： Biofilter Flow rate Purification efficiency Stocking biomass Water quality

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Effective depth-of-penetration range due to hardness variation for different lots of nominally identical target material

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Defence Technology（防务技术） 2016年第2期12卷 171-176页

作者： patrick FRUEH Andreas HEINE Karl Ernst WEBER matthias WICKERT fraunhofer EmI Eckerstrasse 479104 FreiburgGermany

The effect of small variations of target hardness on the depth of penetration for nominally identical target material has not been addressed systematically in publications yet and is often neglected. An investigation of this issue for laboratory-scale long rod projectiles penetrating into semi-infinite rolled-homogeneous-armor steel targets was conducted. The tungsten-heavy-alloy penetrators were of length 90 mm and diameter6 mm. Five lots of armor steel with a nominal hardness range of 280–330 BHN provided material for the targets. The pursued approach consisted of hardness testing of the targets, in total 17 ballistic experiments at velocities in between 1250 m/s and 1780 m/s and data analysis.A linear regression analysis of penetration vs. hardness shows that a target hardness increase within the given range of 280–330 BHN may result in a reduction of penetration depth of about 5.8 mm at constant velocity. This is equal to a change of-12% at an impact velocity of 1250 m/s. A multiple linear regression analysis included also the influence of yaw angle and impact velocity. It shows that small yaw angles and slight variations of impact velocities provide a smaller variation of the semi-infinite penetration depths than a variation of target hardness within a typical specification span of 50 BHN. For such a span a change in penetration of approximately-4.8 mm due to hardness variation is found, whereas 1°of yaw angle or-10 m/s of velocity variation gives a change of about-1.0 mm respectively-0.9 mm. For the given example, the overwhelming part of the variation is to be attributed to hardness effects – 4.8 mm out of 5.8 mm(83%). For nominally identical target material the target hardness thus influences the ballistic test results more severely than the typical scatter in impact conditions.

关键词：硬度变化渗透深度靶材料一元线性回归分析多元线性回归分析地段穿透深度冲击速度

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