bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of Granulation and Effect of Polymers on Theophylline Release from Matrix Tablets
Authors: Azam Kazi Rashidul , Razzak Md Shaikhul Millat Ibn , Khan Ferdous , Islam Muhammad Shahidul , Rony Md Ruknuzzaman , Reza Md Selim
Published: March 2009

The effects of plastic, hydrophilic and hydrophobic types of polymers and impact of granulation process were investigated on the release profile of theophylline from matrix systems. A comparative release characteristics were evaluated by the use of polymers from different theophylline matrices. Matrix tablets of theophylline using Methocel K4M, Ethocel 20 cps, Kollidon SR were prepared separately by direct compression and moist granulation process. In this investigation the feasibility of moist granulation technique in the development of sustained release matrix tablet of theophylline was studied. The kinetics of the dissolution process was determined by analyzing the dissolution data using various kinetic equations, e.g. zero-order, Higuchi and Korsmeyer equations. The mean dissolution time (MDT) was calculated for all the formulations. The analysis of the dissolution data showed that the release process involves erosion and diffusion. Drug release was different from different classes of polymeric matrices and from tablets prepared by different manufacturing processes. The results showed that the profile and kinetics of drug release were the functions of polymer type, polymer content and granulation process. Key words: Theophylline, Moist granulation, Direct compression, Methocel K4M, Ethocel 20 cps, Kollidon SR doi: 10.3329/dujps.v7i2.2168 Dhaka Univ. J. Pharm. Sci. 7(2): 133-139, 2008 (December)
Secondary Metabolites from Bryophyllum daigremontianum
Authors: Nahar Kamrun , Khan Mohammad GU , Rahman Mohammad S , Hasan Choudhury M , Rashid Mohammad A
Published: March 2009

A total of four compounds were isolated from the n-hexane soluble fraction of a methanolic extract of the whole plant of Bryophyllum daigremontianum. The structures of the isolated compounds were elucidated as 11-oxo-epi-Î²-amyrin (1), 21-dehydrodesmosterol (2), 3,4-dihydroxy-cis-cinnamic acid (3), and p-hydroxy-benzaldehyde (4) by high field NMR analyses as well as by comparison with structurally related compounds. Key words: Bryophyllum daigremontianum, Crassulaceae, 11-oxo-epi-Î²-amyrin, 21-dehydrodesmosterol, 3,4-dihydroxy-cis-cinnamic acid, p-hydroxybenzaldehyde. doi: 10.3329/dujps.v7i2.2169 Dhaka Univ. J. Pharm. Sci. 7(2): 141-144, 2008 (December)
Impact of Urinary Arsenic Level on Simple Diffuse Goiter
Authors: Hossain Md Sharif , Begum Fatema
Published: March 2009

The impacts of urinary arsenic level on simple diffuse goiter was studied in Bangladeshi population. A correlation of urinary iodine, radioiodine uptake, thyroid stimulating hormone (THS) and free thyroxin (FT4) levels was made on urinary arsenic level using a case-control analytical study. Out of 85 subjects 45 were considered for experimental group with simple diffuse goiter and rest 40 were considered for healthy control group without any thyroid disease. From the experimental results it has been found that iodine deficiency is not only the factor of causing simple diffuse goiter, but arsenic level is also one of the most important factors of causing simple diffuse goiter. It has also been found that the radioiodine uptake levels at 2 hours and 24 hours and the serum FT4 have negative impacts on arsenic levels for both the experimental and control group. Their impacts are not statistically significant except the variable radioiodine uptake levels at 24 hours. The serum TSH has positive impact on arsenic level for both experimental and control groups but not statistically significant. The estimated results revealed that the variable radioiodine uptake level at 24 hours play the significant role for reducing arsenic level. Key words: Urinary Arsenic, Iodine Deficiency, Simple Diffuse Goiter, Urinary iodine, Thyroid Stimulating Hormone, Free Thyroxin and Radioiodine Uptake Level doi: 10.3329/dujps.v7i2.2173 Â Â Â  Dhaka Univ. J. Pharm. Sci. 7(2): 161-168, 2008 (December)
Studies on Swelling Behavior of HPMC based Matrix Tablets by the Application of Digital Imaging Technique
Authors: Dewan Irwin , Elias-Al-Mamun Md , Jalil Reza-ul
Published: March 2009

The widespread application of hydrogels in a number of applications like control of microfluidic flow, development of muscle-like actuators, filtration/separation and drug delivery makes it important to properly understand these materials. Understanding hydrogel properties is also important from the standpoint of their similarity to many biological tissues. The degree of swelling as well as the rate of swelling of the hydrogel was studied through experiments using digital photography. First of all the matrix was prepared by blending properly weighed HPMC, Theophylline and excipients in a laboratory mixture for 10 minutes followed by compression with 5 ton force for 30 seconds. The study was designed to evaluate the effect of hydrophobic materials on HPMC matrix tablets in terms of in vitro swelling study. Different viscosity grades of HPMC i.e. 6- cps, 15-cps and 50-cps were used to prepare tablets along with various hydrophobic materials. Among the hydrophobic materials stearic acid (SA), cetyl alcohol (CA), bees wax (BW), glyceryl monostearate (GMS), cetostearyl alcohol (CSA) and stearyl alcohol (STA) were used. It was found that presence of hydrophobic ingredients in the HPMC hydrogel matrix substantially reduces swelling of the matrix. In this work, the extent of swelling of HPMC matrix was evaluated by using digital photography and counting the pixels with Photoshop software. Finally, it was shown from the experiment that the rate and extent of drug release is mainly governed by swelling rate of different HPMC viscosity grade used and the nature of hydrophobic materials included into the matrix system. Key words: Swelling, Matrix, HPMC, Hydrogel, Photography. doi: 10.3329/dujps.v7i2.2174 Dhaka Univ. J. Pharm. Sci. 7(2): 169-175, 2008 (December)
Antidiabetic Activity of Stems of Hemipararsite Dendrophthoe falcata Linn. Parasitic Growing on Mangifera indica
Authors: Anarthe SJ , Bhalke RD , Jadhav RB , Surana SJ
Published: March 2009

In the present investigation, we tested the possible cytoprotective and oral hypoglycemic effects of methanolic extract of stems of Dendrophthoe falcata. Besides, total phenolics and total flavonoids were also investigated. The methanolic extract of D. falcata at 200 mg/kg has also shown significant cytoprotective activity (p < 0.05) in alloxan-induced diabetic rats. In addition the extract significantly reduced the elevated level of blood cholesterol (p < 0.01) and triglyceride (p < 0.05). At the same dose level, the extract significantly improved the alloxan-induced reduction of blood protein level (p < 0.01) to normal value. Key words: Antidiabetic activity, Hemiparasite, Dendrophthoe falcata doi: 10.3329/dujps.v7i2.2175 Dhaka Univ. J. Pharm. Sci. 7(2): 177-180, 2008 (December)
Two Views of History and Human Future: Qur'anic and Biblical Renderings of Divine Promises
Authors: Neuwirth Angelika
Published: March 2009

Though the Qur'an refers to the Psalms as a scriptural corpus, al-zabūr, the Qur'anic relationship with the Psalms is – unlike that with the Torah or the Gospel – not explicitly described in terms of an affirming re-collection of that scripture. In the Qur'an ‘the Psalms’ as a scriptural authority play a rather marginal role. Yet individual psalm texts are strikingly present in the Qur'an. Not only are they reflected in numerous Qur'anic metaphors, but more generally, their particular vision of human-divine relations is closely related to that mirrored in the early suras.

The paper attempts to trace the Qur'anic references to Psalm 136 which, it is argued, is theologically radically re-modelled in Sūrat al-Raḥmān (Q. 55), comparing the texts in order to explore the Qur'anic rejection of the Biblical notion of ‘history as a promise for the future’. It will posit that the new Qur'anic vision of the human future that eventually comes to replace the Biblical is not only a rejection of a previous option, it is at the same time a response to a major question raised in Pre-Islamic Arabic poetry. The Qur'an thus is in conversation with two cultural traditions; the options put forward in both being debated and finally replaced.
Transcribing God's Word: Qur'an Codices in Context
Authors: Blair Sheila S.
Published: March 2009

For Muslims the Qur'anic text is immutable, yet written versions vary enormously in materials, format and aspect. This article presents a broad overview of the various forms Qur'an codices have assumed during the first millennium of Islamic history, treating these manuscripts as both physical objects and cultural signifiers. It takes a functional approach, relating physical changes such as differing materials and format to social and historical ones such as changes in the status of copyists and illuminators who made these manuscripts, changes in the types of people or institutions for whom these written versions were made, and changes in the ways that these manuscripts were used. It concentrates on three of the finest examples that are well known, relatively well published, and readily dated or datable – the codex endowed by the ʿAbbāsid governor of Damascus in 262/875–76; the codex copied by the calligrapher Ibn al-Bawwāb in 391/1000–1; and the multi-volume codex copied by Aḥmad al-Suhrawardī between 702/1302 and 707/1308 – thereby showing how study of the objects themselves can help us understand the changing nature of Muslim societies, particularly at the highest levels.
Body-Language in the Qur'an: An Overview with Selected Examples
Authors: ʿArār Mahdī
Published: March 2009

This article identifies some aspects of body language found in the Qur'an, and investigates their meaning. Examples of movements discussed include those of the head, the eye, the hand, the face, and the way people walk. The study begins with an evaluation of body language in terms of various physical positions and what these suggest. Likewise, it will explore the movement of the fingers, and what these suggest.
In Vitro Models in Biocompatibility Assessment for Biomedical-Grade Chitosan Derivatives in Wound Management
Authors: Keong Lim Chin , Halim Ahmad Sukari
Published: March 2009

One of the ultimate goals of wound healing research is to find effective healing techniques that utilize the regeneration of similar tissues. This involves the modification of various wound dressing biomaterials for proper wound management. The biopolymer chitosan (b-1,4-D-glucosamine) has natural biocompatibility and biodegradability that render it suitable for wound management. By definition, a biocompatible biomaterial does not have toxic or injurious effects on biological systems. Chemical and physical modifications of chitosan influence its biocompatibility and biodegradability to an uncertain degree. Hence, the modified biomedical-grade of chitosan derivatives should be pre-examined in vitro in order to produce high-quality, biocompatible dressings. In vitro toxicity examinations are more favorable than those performed in vivo, as the results are more reproducible and predictive. In this paper, basic in vitro tools were used to evaluate cellular and molecular responses with regard to the biocompatibility of biomedical-grade chitosan. Three paramount experimental parameters of biocompatibility in vitro namely cytocompatibility, genotoxicity and skin pro-inflammatory cytokine expression, were generally reviewed for biomedical-grade chitosan as wound dressing.
GPS Velocity and Strain Rate Fields in Southwest Anatolia from Repeated GPS Measurements
Authors: Erdoğan Saffet , Şahin Muhammed , Tiryakioğlu İbrahim , Gülal Engin , Telli Ali Kazım
Published: March 2009

Southwestern Turkey is a tectonically active area. To determine kinematics and strain distribution in this region, a GPS network of sixteen stations was established. We have used GPS velocity field data for southwest Anatolia from continuous measurements covering the period 2003 to 2006 to estimate current crustal deformation of this tectonically active region. GPS data were processed using GAMIT/GLOBK software and velocity and strain rate fields were estimated in the study area. The measurements showed velocities of 15-30 mm/yr toward the southwest and strain values up to 0.28-8.23x10-8. Results showed that extension has been determined in the Burdur-Isparta region. In this study, all of strain data reveal an extensional neotectonic regime through the northeast edge of the Isparta Angle despite the previously reported compressional neotectonic regime. Meanwhile, results showed some small differences relatively with the 2006 model of Reilinger et al. As a result, active tectonic movements, in agreement with earthquake fault plane solutions showed important activity.
Opportunity and Problem in Context (OPiC): A Framework for Environmental Management
Authors: Tsetse David , De Groot Wouter T.
Published: March 2009

Most frameworks used in the management of environmental problems focus on problem analysis and pay little or no attention to the explanation of the problem and the opportunities for solving it. The Opportunity and Problem in Context (OPiC) framework aims to be fully balanced in this respect. On a broad theoretical footing, the framework can give structure and interconnection to (i) the analysis and explanation of environmental problems by making use of parallel effect chains and norm chains, the functions and values of the environment, a breakdown of human action through lifecycle principles and explanation through fields of causally related actors, (ii) the identification of opportunities for solutions based on the problem analysis, on system concepts and on creativity enhancement, and (iii) the synthesis of this in the process of design and evaluation of solutions. The OPiC framework has been developed with a special view to developing countries but its applicability is not greatly dependent on scale and context.
Quantifying Values: A Sampling Methodology for use in Assessing the Impacts on Tourism, Local Community, and Businesses of Victoria's Marine Protected Areas
Authors: Hall Nina , Sillitoe Jim
Published: March 2009

A sampling methodology has been devised to facilitate the selection of a purposeful sample of marine parks and sanctuaries for the investigation of their impacts on tourism, local community, and businesses. The methodology is based on multiattribute utility theory used for comparing
complex alternatives in decision making and takes into account those key attributes of Victoria's 13 marine national parks and 11 marine sanctuaries that have been identified through both published and draft management plans, government policies, and relevant strategies. The attributes are:
tourism services, activities, community engagement, visitation, values, interpretation, access, location, conservation significance, and regional context. Values of each marine protected area are quantified and establishment of a total attribute value score for a "typical area" enables the
comparison between individual marine parks and sanctuaries. To strengthen the methodology, a panel of independent experts representing tourism, local government, and community organizations were invited to express their views with regard to these attributes, and their responses have been incorporated
into the research.
The Socioeconomic Impacts of Cruise Tourism: A Case Study of Croatian Destinations
Authors: Marušić Zrinka , Horak Siniša , Tomljenović Renata
Published: March 2009

The aim of this research was to estimate the economic, promotional, and sociocultural impact of cruise tourism to Croatian destinations. Due to the anticipated growth of cruise tourism worldwide and, especially, in the Mediterranean, measuring its impacts is becoming an increasingly
important issue in terms of appropriate planning of cruising tourism on the local level. The study reported here included the survey of cruise ship passengers and crew members in order to estimate their on-land expenditure, survey of hotel guests aimed to estimate the impact of cruise experience
on repeat, land-based, visits, and survey of local residents aimed to estimate the sociocultural impact of cruise ship tourism. The study found that, in terms of the passenger- and crew-related expenditure, cruise passengers were relatively good spenders. They spent between 34 and 82 Euros,
depending on the port of call. In terms of the value of cruising upon the return visit to a destination, the survey revealed that only between 1.5% and 3% of cruise passengers who visited Croatian destinations during 2000–2006 returned in 2006 as land-based visitors. In destinations
with frequent cruise ship calls the negative impact on destination attractiveness is already present. Land-based tourists disliked seeing cruisers/cruise passengers in destination (23%), and were complaining of the noise generated by the cruise ships. Finally, residents also reported the adverse
impact of cruisers and their passengers relating mostly to the excessive crowdedness created in the short time. However, they still supported cruise tourism, albeit advocating an urgent need to improve the traffic and visitor flow management. With an understanding of the economic value of
the cruise industry and the range of the impact that it creates on land-based tourists and residents' community, the results are very important for drafting the strategic direction for cruise tourism development already under way in Croatia.
Conservation and Education Benefits of Interpretation on Marine Wildlife Tours
Authors: Zeppel Heather , Muloin Sue
Published: March 2009

Marine wildlife tourism can provide a range of education and conservation benefits for visitors. These benefits derive from close personal encounters with marine wildlife and visitor learning about marine species and ocean environments. There has been limited assessment of marine wildlife
tourism experiences and educational programs to identify whether these increase tourists' knowledge, promoting attitudinal shifts and also lifestyle changes that aid marine conservation and help to conserve marine wildlife. Similarly, there has been little evaluation of on-site and longer
term conservation intentions, or behaviors, of visitors that benefit marine wildlife and environments. This article reviews the education and conservation benefits of marine wildlife experiences in Australia using Orams' framework of indicators to manage marine tourism. The key indicator for
tourists assessed in this article is behavior/lifestyle change that benefits marine species, along with three indicators of conservation outcomes for marine environments. Information is drawn from selected case studies of research on guided tourist encounters with whales, dolphins, and marine
turtles from 1996 to 2007, mainly in Australia. This analysis found tourist learning during mediated encounters with marine wildlife contributes to proenvironmental attitudes and improved on-site behavior changes, with some longer term intentions to engage in conservation actions that benefit
marine species.
Deepwater Flowline Tie-Ins and Jumpers: What Works Best?
Authors: McKeehan D.S. , Freet T.G.
Published: March 2009

The diverless tie-in of pipelines has evolved into three techniques whichare being standardized for first or second end connections in depths of 1,000feet and deeper: lateral deflections, spool pieces, and vertical stab andhingeover. This paper discusses the trade-offs made when determining the mostcost-effective solution for deepwater flowline tie-ins and jumpers forwell-to-manifold tie-ins. Since deepwater tie-ins have a significant impact onpipeline economics, the selection process depends on many factors which areordinarily not considered in shallower depths.

Introduction

The DeepStar project selected the cluster satellite well and manifoldconcept for further development. A critical aspect of this modular equipmentarrangement is the numerous piping interconnections that must be made betweenthe satellite wells and the manifold; and, between the manifold andflowlines/riser bases.

Diverless tie-in of the satellite wells connects the small diameter pipesused for production (4"), well test (4"), hydraulic fluids (1") andchemical service (1") lines to the manifold. These "jumper" pipesrange from 60 ft to about 150 ft in length, depending upon the location of thewell relative to the manifold connection point. The connectors may be hydraulicor mechanical and operated by an ROV. With planning, it may be possible tomeasure, fabricate and install these jumpers from the field Mobile OffshoreDrilling Unit (MODU) while not interrupting the drilling operation.

Diverless tie-ins for "flowlines" of 8 to 20 inch diameter in awater depth range of 1,000 ft to 6,000 ft are being considered and implementedby operators as the technology advances. The increasing water depths and keeninterest by the engineering community have resulted in a variety of tools andtechniques being proposed for these tasks. The options available andlimitations of each frequently necessitate trade-off comparisons andengineering studies to establish the most practical arrangement for a specificfield development. This paper presents the applications and requirements ofconnection systems both for the flowline tie-ins and for the connection of thesatellite wells to the manifold. To focus discussion, the term "tie-in"represents the initial placement of the flowline and subsequent activitiesnecessary to align and position mating connector halves within theirself-engagement envelope. Similar to the jumper, the flowline connections areoptimized for ROV operation.
Deepwater Technology Limits and Development Barriers
Authors: Chitwood J.E. , Rothberg R.H. , Miller H.W.
Published: March 2009

A phased deepwater subsea cluster manifold producing over an extendeddistance to a shallow water host production platform has been evaluated forGulf of Mexico economic viability in the DeepStar program. This paper examinesexisting subsea production technology to identify upgrades and improvementsnecessary before a junctional and cost effective deepwater system can bedeployed. Beyond the basic technology upgrades, several cost reductiontechnologies are also identified.

Introduction

Subsea production system technology is presently suited for applications inwater as deep as 3000 - 3500 ft. The DeepStar program evaluated developmentalternatives in water as deep as 6000 ft in the Gulf of Mexico, and found thatexisting subsea technology can be extended to this depth with substantialfunctional similarity. Some basic differences exist as a result of location, reservoir conditions and the recommended seafloor facility arrangement. Thesedifferences are briefly identified to highlight technologies requiring furtherdevelopment. With technology upgrades, a working system could be assembled forthe deepwater Gulf, however, it may not be economically viable. Furthertechnology work, therefore, needs to focus upon cost reduction strategies toimprove deepwater field development economics.

The DeepStar project developed a phased modular production system. Thesubsea facilities feature clustered satellite wells around one or moremanifolds, linked by flowline jumpers. If required, subsea processing orpumping is placed in series between the manifold and the pipelines. Thesepipelines extend to an existing platform in shallow water on the continentalshelf. During the early project drilling phase, the subsea wells are producedto gain both information and confidence in the reservoir, and to improve theproject's economics. Each well is placed into production as it is completed. These subsea facilities are controlled from the Mobile Offshore Drilling Unit(MODU) until the drilling program is complete. The control umbilical to theshallow water host is then installed and tied-in to operate the field duringits production decline phase.
A More Realistic Method for Predicting the Compatibility of Thermoplastic Hoses When Used in Subsea Umbilical Systems
Authors: Stables J.D. , Dodge I.R. , MacRaild Donald
Published: March 2009

Historically, predicting the service life for thermoplastic materials ofhose construction was based on the immersion of material samples in servicefluid at elevated temperatures. This is often referred to as "acceleratedageing" and the rate of change in the physical properties with time hasbeen used to predict the likely service life. This method of testing takes noaccount of the anisotropic nature and the processing history of a thermoplastichose liner, in addition to the possible instability of control and well servicefluids. A new method of testing, coupled with correlation factors derived fromactual measurements of the physical properties of the tested hose liners, allows the Arrhenius formula for the rates of chemical reaction to be morerealistically applied to thermoplastic hoses. The test method is designed tomore accurately simulate real life service conditions.

This paper examines the historical aspects of compatibility testing and thereasons for the change in the test method. Results and observations of a testprogramme with water based control fluids are presented to illustrate howphysical properties can change with time and their correlation with theArrhenius equation.

Introduction

An umbilical cable is defined as a group of hydraulic lines or electricalcables, either on their own or with combinations of each other (or opticalfibre units), cabled together for flexibility and oversheathed and/or doublewire armoured for mechanical and tensile strength. Such an arrangement is showntypically in Figure 1.

The hydraulic lines can be employed for a variety of duties, typically:Power (operation of actuators)Signal (operation of pilot control valves)Data (pressure monitoring)Fluid transmission (well service and platform utilities)
Achieving Cleanliness Levels During Fabrication, Assembly, and Testing of Subsystems and Hydraulic Tubing Network for the Zinc Subsea Production System
Authors: Loes George , Greenlay Tim , Caldwell J.W.
Published: March 2009

The Exxon Zinc Subsea Production System utilizes an electrohydraulic controlsystem to perform various equipment functions subsea, and to provide status ofequipment and well conditions to the Alabaster host platform. The hydraulicfluid utilized is water-based Marston Bentley HW 525 with a cleanlinessrequirement of NAS 1638 class 8 or better. This cleanliness level is requiredfor the proper operation of subsea valves over the duration of systemoperation. This paper discusses the methodology, procedures and equipmentrequirements to achieve and maintain this cleanliness level. It addresses thesurface equipment that stores and supplies the control fluid, the hydraulicumbilicals that carry the fluid to Zinc, the subsea hardware, and variousrunning tools that could interface with the subsea hydraulic network. Componentcleaning, clean room operations, hydrostatic testing and system flushing arediscussed. The cleanliness monitoring QC steps during system integration andtesting are also presented.

Introduction

The Exxon Zinc Project is a Subsea Production System located in the Gulf ofMexico - Mississippi Canyon area. The project includes a ten-well subseatemplate and manifold production system situated in 1,460 feet of water tiedback to the Alabaster platform 6 miles to the west in 468 feet of water. Gasproduction is achieved through three flowlines. Well control is achievedthrough an electrohydraulic control system via separate electrical andhydraulic umbilicals. The flowline and umbilical connections at Zinc are byremote diverless methods. The multiplexed control system incorporates a subseacontrol skid which houses the control pods. A hydraulic tubing networkinterconnects the control skid pod bases with the ten tree locations, and thepigging valve manifold interface. There are approximately 2,000 feet of tubingin the control skid and 14,000 feet in the manifold tubing network. Thisconsists of 3/4" OD × 3/8" ID super austenitic stainless steel tubingand fittings preassembled and socket welded into place.

In addition to the above, there are tubing runs within each control pod, subsea tree and the pigging valve assembly. This tubing interconnects thevarious control valves and subsea gate valve actuators. Hydraulic fluid issupplied to the control skid through a nineteen hose hydraulic umbilical. TheNYLON hoses, are arranged concentrically and protected by layers of medium andhigh density polyethylene and jacketed armor wire.
New Method for Concrete Coating of Marine Linepipe
Authors: Mordhorst Tage , Pallesen Jes
Published: March 2009

Laying of offshore pipeline for oil and gas has increased rapidly over thelast ten years and a number of very large diameter pipelines have beeninstalled or are planned for.

Offshore pipelines of diameter 16 inch and up are usually stabilized on theseabottom by a concrete coating applied to the 12 m long joints before they areshipped to the laybarge.

The concrete application is normally undertaken at coating yards using theimpingement method or the compression coat method with thickness of the coatingvarying from 50 mm to 120 mm.

In this paper a novel concrete application method is described givingdetails of how the method waS developed, the erection of a coating plant, testing of the product and its first full scale industrial application.

Unique features of the new application method are emphasized especially withregard to vibration of the concrete and the advantages to be gainedherefrom.

Finally an evaluation is presented of the possibilities which the new methodoffers to the pipeline designers together with an indication of the advantagesthat the pipeline operators may gain from the new concrete coating method.

Introduction

During the coating of the first major marine pipelines in Denmark in 1980–84the impingement method for concrete coating of offshore line pipe was employedat a Danish coating yard.

It was observed by the newcomers to the pipe coating industry that theheavy-weight concrete coating was obtained by adding iron ore to a concretemix, which through the throwing action of the impingement method resulted in acomparatively porous coating. Furthermore, a cement content of 500–600kg/m3 was required to make the no-slump mix stick to the rotatingpipe.

In the construction industry, based upon modern concrete technology, acement content of 350 kg/m3 is normally adequate, and vibrationduring application is used to produce a strong, dense and durable concrete. Amore dense concrete would require less iron ore content to result in a givenunit weight.
Fatigue Properties of Hyperbaric Dry Repair Welds
Authors: Petershagen H.F. , Hoffmeister Hans
Published: March 2009

Fatigue data for repair welded offshore structures are still lacking. As acontribution to this subject, laboratory tests on the fatigue strength ofhyperbaric dry repair welded butt welds have been carried out. The tests werecarried out in air. The data thus represent the fatigue strength of repairwelds in structures operating in air or with cathodic protection. In order toobtain reference data the H16- process with optimized welding parameters wasapplied for repair welding. In forthcoming phases of the project the effect ofweld imperfections will be included as well as the influence of seawater. Thepartly large secondary bending stresses due to the angular distortion of thespecimens were calculated by means of a simple beam model. Residual tensilestresses between 30% and 60% of the yield stress were measured perpendicular tothe repair weld at the weld toe. Fatigue strength of initial and repair weldhave been found to be equivalent. With angular distortions within usual limitsthe repair weld can be ranked as a class 90 detail according to the IIW FatigueDesign Recommendations. Block program tests showed the validity of Miner'srule.

Introduction

Service loads acting on offshore structures are to a large extent fatigueloads. With the increasing age of many structures and a tendency towards anextension of service life the fatigue strength of repair welds requires specialattention. In the investigation described in this paper the repair of a surfacecrack at the toe of a butt weld under hyperbaric conditions was simulated andthe fatigue properties of the repaired weld have been studied. This study ispart of a research project "Damage investigation and prevention in underwaterstructures." The project is supported by Deutsche Forschungsgemeinschaft (DFG). Full details of the study are given in 1. While optimized repair weldingparameters were used in the present study and the fatigue tests were carriedout in air, the effect of weld imperfections as well as of corrosive seawaterenvironment will be included in further stages of the project.
Ultrasonic Impact Peening Treatment of Welds and Its Effect on Fatigue Resistance in Air and Seawater
Authors: Tryfyakov V.I. , Mikheev P.P. , Kudryavtsev V.F. , Reznik D.N.
Published: March 2009

Welding residual stresses and stress concentrations are main factors whichdetermine the load carrying capacity of welded structures under multicyclicloading conditions as typically experienced by ships and offshore structures. To improve fatigue performance the E. O. Paton Institute recently introducedUltrasonic Impact Peening Treatment. This local treatment of the weld toe iscarried out by means of specially-developed equipment consisting of amagnetoconstriction convertor, an ultrasonic wave transmitter and a specialtool with holder. The tool tip using either a single 16mm ball element ormultiple needles, vibrates at 27 KHz with maximum axial amplitudes up to 30microns. The tool holder isolates the operator from the vibration and there islittle audible sound during the treatment.

The process:Introduces compressive residual stresses (up to 900 MPa at and near thesurface) into areas of high stress concentration.Reduces stress concentration associated with weld local geometry.Creates plastic deformation strain hardening in a surface layer (up to 0.7mmin depth).

This paper briefly describes the fatigue test results obtained from plateand tubular connections in air and sea water. The cyclic endurance increasesfrom 2 to 10 times and the fatigue limit increases from 27% to 200% dependingon the type of joint, base material strength and load ratio.

Introduction

Many structural weldments - offshore platforms, cranes, bridges, antennas, and other structures - are subject to the action of large numbers of cyclicloads during service. The development of fatigue fractures amounts toapproximately 30% of the total premature failures in these structures. Thefatigue limit of butt welds in different strength classes of steel establishedby the criterion of fatigue crack initiation is reduced to 32% to 46% of thefatigue limit of the corresponding parent metal with a rolled surface. Similarly, the fatigue limit of lap joints with longitudinal fillet welds undercyclic stress conditions constitutes only 20% to 40% of the fatigue limit ofthe corresponding parent metal [1, 2].
Transportation of Highly Waxy Crude in Offshore South China Sea: A Rheology and Flowline Simulation Study
Authors: Zheng Guohua , Holbrook J.A. , Bernal Alvaro , Santamaria M.M. , Williams T.M. , Brubaker J.P.
Published: March 2009

The HZ crude from South China Sea had a high wax content and formed stablewater/oil emulsions with the produced water. Transportation of this crudecalled for deployment of ESP's (Electric Submersible Pump) downhole, utilization of existing infrastructure, flowlines connecting various productionplatforms, and water treatment facilities aboard the platforms. Questions onthe ESP effect on emulsion viscosity, the non-Newtonian nature of the emulsion, and the operating environment all made the design of the production systemunique and challenging. A series of laboratory tests were conducted to providerheology data necessary for the production system design. These data weresometimes confusing and seemingly conflicting, and had to be sorted out forrealistic simulation. Once the appropriate data were obtained, simulations wererun to determine the minimum insulation requirement for the flowlines, pressures and temperatures at each platform and at FPSO (Floating ProcessStorage and Offloading) for various production scenarios.

Introduction

The South China Sea HZ wells produce a high wax content crude which exhibitsnon-Newtonian flow behavior. Past testing has shown that the crude formsstable, tight water/oil emulsions with the produced water. An extensiverheology study was thus conducted in Texaco EPTD facilities to obtainexperimental data needed for proper design of this offshore production system. As part of this study, simulation runs were performed to provide basis for adetailed design.

The proposed configuration of the production system is shown in Fig. 1. Thesystem utilizes the existing infrastructure of HZ 1, namely facilities on theHZ 1 platform, HZ 1 line and the FPSO. Thus, production from the HZ 2, 3, and 1platforms are tied in series to the FPSO. Due to the handling capacities offacilities on the HZ 1 platform, fluid from the HZ 3 line joins with the HZ 1production at the pump outlet. Fluid from the HZ 2 line meets with the HZ 3production at the separator. The HZ 3 separator is designed to remove most ofthe water from the HZ 2 and 3 production. The existing HZ 1 facilities cantreat and dispose a maximum of 26 MBWPD.
The Zinc Subsea Production System: An Overview
Authors: Bednar J.M.
Published: March 2009

Located in 1460 feet of water in the Gulf of Mexico, Exxon's Zincdevelopment utilizes a subsea production system to produce gas to a hostplatform six miles away. The ten-slot subsea template, designed specifically toaccommodate the soft soil conditions at the Zinc site, supports the non-TFLwells, which are controlled by means of an electrohydraulic control system. Keyfeatures of the development are described in this paper.

Introduction

The Zinc development is a gas field located in the Gulf of Mexicoapproximately 50 miles south of Grand Isle, Louisiana (see Fig. 1). Designatedas the Mississippi Canyon (MC) Block 354 unit, the field is comprised of blocksMC 354, 355, 398, and 399. For production, a ten-slot subsea template ispositioned on block MC 355, with wells directionally drilled to the designatedbottomhole locations. Water depth at the template site is 1460 feet. Exxon isthe sole operator of the development.

The host platform is Exxon's "Alabaster" platform locatedapproximately six miles to the west in block MC 397 (see Fig. 2). The platformis located on a knoll in 468 feet of water. Production from Zinc is transportedto Alabaster via two 8" and one 4" flowlines. The subsea wells arenon-TFL and controlled by means of an electrohydraulic control system.

In defining the Zinc development system, Exxon strived to useindustry-proven designs and technology wherever possible and practical. Toensure reliability, an active Quality Assurance program was implemented throughall phases of the project, from design and fabrication, to installation andstart-up. Much emphasis was placed on Factory Acceptance Testing, to ensurethat the delivered equipment would properly meet the designated performancestandards. An eight-month System Integration Test was then conducted to ensurethat when married together, the individual components and subsystems wouldperform satisfactorily as a total system. Installation, drilling, andoperations personnel were actively involved to ensure a smooth transition tothe end-users.

The Zinc subsea production system is Exxon's first commercial subseatemplate in the Gulf of Mexico. It is also currently industry's largestmulti-well satellite subsea system in the Gulf.
Zinc Flowlines
Authors: Weir M.S. , Bednar J.M. , Watson J.C. , Beckman M.M. , Hale J.R. , Stearns J.P.
Published: March 2009

Three flowlines are used to transport the gas produced from the Exxon Zincsubsea production template (in MC355) to the Alabaster platform (in MC397). Each flowline installation was initiated from Alabaster with a J-tube pull andlaid down into target areas at Zinc. Diverless subsea connections at Zinc werecompleted using the second end lateral deflection method and a diverlessROV-operated collection system.

Description of Flowline System

The Zinc subsea production system is a gas development in 1460 feet ofwater, located in the Mississippi Canyon area of the Gulf of Mexico. Fullwellstream production will be delivered to the Alabaster platform located 6miles to the West in 468 feet of water through a dual 8-inch and single 4-inchflowline system.

The 4-inch flowline is designed for a maximum working pressure of 5000 psito transport gas from the high pressure wells. The 8-inch flowlines aredesigned for a maximum working pressure of 3705 psi to transport gas from thelow pressure wells. Table 1 summarizes the characteristics of the threeflowlines. The maximum working pressures were selected to withstand wellshut-in pressure.

The flowlines and associated piping are designed to allow pigging operationsfrom the Alabaster platform through a removable Pigging Valve Assembly (PVA) onthe manifold piping of the subsea template. The PVA is controlled fromAlabaster through the control system at Zinc and can be configured for variouspigging operations. The dual 8-inch lines allow round trip pigging operationsto be carried out from Alabaster. A parking block in the PVA also allows an8-inch pig to be parked and returned through the same 8-inch line. Pigging ofthe 4-inch line can be performed by pumping the pigs from Alabaster and dumpingthem into the 8-inch loop at Zinc or by using a parking block on the PVA whichallows the pig to be returned to Alabaster in the 4-inch line.
Zinc Electrical and Hydraulic Umbilical Connection Systems
Authors: Fontenette L.M. , Bednar J.M. , Beckman M.M. , Hale J.R. , Hellums J.W.
Published: March 2009

The connection of the electrical and hydraulic umbilicals to the Exxon Zincsubsea production template was accomplished using first-end connection systemsdesigned to be diverless and utilize guidelines for deployment.

This paper describes the design, testing and installation of the umbilicalconnection systems developed for the Zinc subsea production system.

Overview

The Zinc subsea production system is a gas development in 1460 feet ofwater, located in the Mississippi Canyon area of the Gulf of Mexico. Separateelectrical and hydraulic umbilicals are used to control the Zinc subseaproduction system from the Alabaster platform, located six miles to the west in468 feet of water. The umbilicals provide the electrical power, communicationlink and hydraulic/chemical injection supply to the multiplex subsea controlsystem on Zinc.

Each umbilical installation was initiated at Zinc using guidelines forlowering and landing an umbilical termination assembly onto its receiver on thesubsea template. After the umbilical termination assembly was landed, theumbilical was laid to the Alabaster platform where a second-end J-tube pull wasperformed to complete the installation.

Final connection of the umbilicals to the subsea template/ manifold wascompleted after the umbilicals had been installed and tested. For the hydraulicumbilical, the connection tool utilized a mechanical clamp to make-up theumbilical connection to the hydraulic fluid distribution system on the subseamanifold. The electrical umbilical connection was completed by attaching anelectrical jumper assembly from the control skid on the manifold to thetermination assembly on the electrical umbilical using a Remote OperatedVehicle (ROV).

Selection of Connection Systems

The umbilical connection systems were selected to feature a first-endconnection at Zinc. The first end connection method allowed close routing ofthe umbilicals to the flowlines near the template, which minimized mooringdifficulties for subsequent drilling operations. After installation wascomplete, the subsea electrical and hydraulic umbilical connections to the Zinccontrol system were made-up. A slack loop near the Alabaster Platform wasincluded in the route to accommodate excess umbilical length prior to thesecond-end J-tube pull. This allowed both umbilicals to be installed withoutmodifying their length in the field.
Severe Maternal Morbidity and Mental Health Hospitalizations or Emergency Department Visits
Authors: Blackman Asia , Ukah Ugochinyere V. , Platt Robert W. , Meng Xiangfei , Shapiro Gabriel D. , Malhamé Isabelle , Ray Joel G. , Lisonkova Sarka , El-Chaâr Darine , Auger Nathalie , Dayan Natalie
Published: April 2024

Importance

Severe maternal morbidity (SMM) can have long-term health consequences for the affected mother. The association between SMM and future maternal mental health conditions has not been well studied.

Objective

To assess the association between SMM in the first recorded birth and the risk of hospitalization or emergency department (ED) visits for a mental health condition over a 13-year period.

Design, Setting, and Participants

This population-based retrospective cohort study used data from postpartum individuals aged 18 to 55 years with a first hospital delivery between 2008 and 2021 in 11 provinces and territories in Canada, except Québec. Data were analyzed from January to June 2023.

Exposure

SMM, defined as a composite of conditions, such as septic shock, severe preeclampsia or eclampsia, severe hemorrhage with intervention, or other complications, occurring after 20 weeks’ gestation and up to 42 days after a first delivery.

Main Outcomes and Measures

The main outcome was a hospitalization or ED visit for a mental health condition, including mood and anxiety disorders, substance use, schizophrenia, and other psychotic disorder, or suicidality or self-harm event, arising at least 43 days after the first birth hospitalization. Cox regression models generated hazard ratios with 95% CIs, adjusted for baseline maternal comorbidities, maternal age at delivery, income quintile, type of residence, hospital type, and delivery year.

Results

Of 2 026 594 individuals with a first hospital delivery, 1 579 392 individuals (mean [SD] age, 30.0 [5.4] years) had complete ED and hospital records and were included in analyses; among these, 35 825 individuals (2.3%) had SMM. Compared with individuals without SMM, those with SMM were older (mean [SD] age, 29.9 [5.4] years vs 30.7 [6.0] years), were more likely to deliver in a teaching tertiary care hospital (40.8% vs 51.1%), and to have preexisting conditions (eg, ≥2 conditions: 1.2% vs 5.3%), gestational diabetes (8.2% vs 11.7%), stillbirth (0.5% vs 1.6%), preterm birth (7.7% vs 25.0%), or cesarean delivery (31.0% vs 54.3%). After a median (IQR) duration of 2.6 (1.3-6.4) years, 1287 (96.1 per 10 000) individuals with SMM had a mental health hospitalization or ED visit, compared with 41 779 (73.2 per 10 000) individuals without SMM (adjusted hazard ratio, 1.26 [95% CI, 1.19-1.34]).

Conclusions and Relevance

In this cohort study of postpartum individuals with and without SMM in pregnancy and delivery, there was an increased risk of mental health hospitalizations or ED visits up to 13 years after a delivery complicated by SMM. Enhanced surveillance and provision of postpartum mental health resources may be especially important after SMM.
Tetrafluoroethylation of Electron‐Rich Alkenyl Iodides Enabled by in situ Generation of Solvent‐Stabilized “Ligandless” CuCF2CF2H
Authors: Segovia Cristina M. , Porto Luana L. T. N. , Casasús Paula , Bascuas Isabel , Ahmad Amena , Mestre Jordi , Bernús Miguel , Castillón Sergio , Baker R. Tom , Boutureira Omar
Published: April 2024

In this study, we have developed a metal‐mediated synthetic method for incorporating the 1,1,2,2‐tetrafluoroethyl (CF2CF2H) motif into unactivated, electron‐rich alkenyl iodides using cross‐coupling reactions. We discovered that the stable Cu(CF2CF2H)(PPh2Me)3 complex, while unreactive with these substrates, serves as a P‐ligated reservoir for the formation of solvent‐stabilized “ligandless” and reactive CuCF2CF2H species. This transformation occurs upon addition of CuBr, which partially scavenges the P‐ligand in the form of CuBr(PPh2Me)3. The resulting in situ generated solvent stabilized “ligandless” system significantly enhances the reactivity of the complex, particularly towards challenging electron‐rich substrates. This advancement enables the synthesis of HCF2CF2‐glycals, as well as nucleosides/nucleobases and arenes.