bluuebunny/crossref_metadata_2025 huggingface dataset:
A Method for Probabilistic Forecasting of Oil Rates in Naturally Fractured Reservoirs
Authors: Blanco Julio César , Palenzuela Rafael Paz , Aguilera Roberto
Published: April 2012

A method is presented for probabilistic forecasting of oil rates in naturally fractured reservoirs (NFRs) based on a new modified Darcy equation. The equation includes variables that have significant impact on productivity of NFRs such as matrix and fracture permeabilities, partitioning coefficient, i.e, the ratio of fracture and total porosity, and thickness of the perforated interval.

To perform the calculations, probability distributions are generated for each one of the above input variables. The locations of the water-oil and gas-oil contacts are determined, as well as the maximum efficient oil rates to avoid premature coning of water and gas. The integration of these data with the modified Darcy equation leads to prediction of maximum, most likely and minimum oil rates that could be anticipated for production wells in different parts of the reservoir.

The difficulties and uncertainties that exist for predicting oil rates in NFRs are widely recognized. The proposed methodology looks to diminish this uncertainty with a view to generate reliable production forecasts, optimize oil rates, improve oil recovery and maximize economic returns.

The modified Darcy equation for NFRs discussed in this paper is not presently available in the literature. The equation is easy and rapid to use statistically, and is being applied in practice with a good level of success. Thus, it provides a valuable supplement to numerical simulation and a significant reservoir engineering tool in those instances where operational decisions must be made quickly.
Dynamometer Charts and Well Weighing
Authors: Fagg L.W.
Published: April 2012

The purpose of this paper is to present in a convenient form data andexample, necessary in making dynamometer card analyses; also to outline aprocedure of well weighing.

Many articles and papers have been written delving into the mathematicalconsiderations relative to the shape and characteristics of dynamometer cards.However, it is recognized that there are too many unknown factors involved insuch calculations to assure a workable degree of accuracy. For this reason theaccepted procedure is to take dynamometer cards on wells in question ratherthan try to calculate the load curve.

The polished rod dynamometer is now recognized as a necessary tool formeasuring loads, torque, and horsepower. It is also used to determine pumpaction and trouble-shoot for any seemingly abnormal pumping condition.

The apparently infinite variety of dynamometer cards that can be obtained isone reason for the general lack of usage of the dynamometer as a controlinstrument rather than a means for making routine measurements of leads andhorsepower. When it is considered that the dynamometer card is a record of theresultant of all forces acting on the polished rod at any particular instantduring the pumping stroke, the problem is then one of breaking down thisresultant into its various components. As a means of a quick review we shallconsider the examples shown in Figs. 1 to 9, and Tables I and II and thenproceed to the interpretation of variously shaped cards caused by some abnormaloperating condition.

In Table II, when we were considering the factors involved in calculating thepeak polished rod load, it can be seen that the factors involved greatlyoversimplify the problem. Certain assumptions are made which mayor maynot be even close to the actual field conditions, such as the specific gravity ofthe fluid generally considered as one; that the crank has constant angularvelocity; that the down-hole friction is zero; and that the fluid lift is fromthe pump. In the following examples we shall see what a variation in fluidweight and friction can do to the general shape and magnitude of thedynamometer card. (Figs. 10 to 22.)

T.P. 2854
Use of Centrifuge for Determining Connate Water, Residual Oil, and Capillary Pressure Curves of Small Core Samples
Authors: Slobod R.L. , Chambers Adele , Prehn W.L.
Published: April 2012

The centrifuge has been found to be an extremely useful tool for determiningcapillary pressure curves and for establishing connate water and residual oilin small core plugs. The use of the centrifuge for determining the propertiesof small core plugs has been discussed in the literature, but practically noexperimental evidence has been presented justifying the use of this method inpreference to other methods (mainly disc method) now in use. Data have beenaccumulated and are now presented demonstrating the advantages of thecentrifugal method, some of which are:rapid establishment of equilibrium,excellent precision yielding very reproducible results,availability ofhigh pressure differences between phases,simple operational procedure, andability to establish connate water, residual oil, or to obtain completecapillary pressure curve in one day or less.

A commercially availablecentrifuge capable of speeds up to 3,800 rpm, and a high speed attachmentproviding a maximum rate of rotation of 18,000 rpm were used in this work inconjunction with core holding tubes designed specifically for thisapplication.

In view of the outstanding advantages associated with the use of thecentrifuge the conclusion has been drawn that this method should be used inplace of the more tedious, slower, and less reliable disc method fordetermining capillary pressure curves and for establishing connate water andresidual oil in small core plugs.

Introduction

The need for accurate values of connate water, residual oil, and capillarypressure curves in reservoir engineering has been recognized for many years, and the extent of the effort devoted toward solving these problems is reflectedin the large number of papers which have appeared in the literature during thepast decade. Most of the methods discussed in the recent literature employ aporous disc as a semi-permeable membrane to separate two immiscible phases andmake possible the application of an explicit difference in pressure between twophases in the core. Thus, in the determination of the capillary pressure curvethe wetting phase (water) is displaced by the non-wetting phase (air oroil).

Several investigators have used centrifugal forces to develop pressuredifferences between phases. As a result of the first work in this field theconclusion was reached that "the more rapid centrifugal method formeasuring irreducible saturation may have equal value, (compared to use ofdiscs) but more work is required to establish this point." This work wasfollowed in 1945 by a more detailed study in which the concepts of thisexperimental work were more clearly enunciated. A method for calculatingsaturation for any given speed of rotation based on the observed volume ofwater displaced was developed and a wider application of the method wassuggested.

T.P. 3052
Fluid Saturation in Porous Media by X-Ray Technique
Authors: Laird A.D.K. , Putnam J.A.
Published: April 2012

This paper describes the application of x-ray theory to design procedures inconnection with fluid saturation determinations during fluid flow experimentswith porous media. A reliable and rapid method for calibrating the x-rayapparatus is described. Extension of the method to fluid saturationdeterminations in three-fluid systems is described.

Introduction

In research on oil production problems a method is required which will givequickly the quantity of each component of a fluid flow system present at anycross-section of a porous medium.

The sample of porous medium under investigation is usually referred to as acore. The ratio of the volume of one component to the total fluid volume isdefined as the saturation of the porous medium by that component. This ratio isgenerally given as per cent saturation.

Some means of measuring saturation which have received considerationinclude: electrical conductivity of the fluids; emissions from radioactivetracers dissolved in the fluids; the radioactivity of silver caused byreflection of neutrons from hydrogen atoms in the fluids, the attenuation of amicrowave beam, the diminution and phase shift of ultrasonic wave trains, andthe reduction in intensity of x-ray beams in passing through the fluids.

X-rays have already been used with some success. Since every material has adifferent power to absorb x-rays, the reduction in intensity of an x-ray beamas it passes through a core depends on the fluids present. The strength of theemergent beam can be found by converting its energy into a measurable form suchas heat or ionic current, or by its effect on a photographic plate orfluorescent screen.. The beam strengths could be interpreted as quantities ofknown fluids in the core if, previously, these beam strengths had beenidentified with a known combination of the same fluids. With some fluidcombinations it might be desirable to dissolve powerful x-ray absorbingmaterials in one or more of the fluids, to increase the differences in the beamstrengths for various fluid saturations.

Boyer, Morgan and Muskat have described a method of measuring two componentfluid saturation. One component was air or water; the other, mineral seal oilin which was dissolved 25 per cent by weight of iodobenzene to increase itsabsorbing power. The x-ray source was a tungsten target tube operated at 43 kvpotential. The beam emerging from the core was measured as ionic currentflowing across an air-filled ionization chamber by means of an amplifyingcircuit and galvanometer. Another portion of the beam from the x-ray tube waspassed through a metal plate and measured in another ionization chamber. Thisportion, called the monitor beam, was used as an indication of the performanceof the x-ray tube. The galvanometer readings were calibrated against air-oilcore saturations, gravimetrically determined. The method was apparentlyestablished by experimental means.

T.P. 3169
Neutron Derived Porosity-Influence of Bore Hole Diameter
Authors: Scotty C.B. , Egan E.F.
Published: April 2012

Introduction

The neutron-gamma log has been used for stratigraphic correlation by the oilindustry for a number of years. In the past few years, the quantitativeapplication of the log to provide information with respect to porosity hasreceived considerable attention. The basic concept of quantitativeinterpretation has been pointed out in the literature. It shall be the purposeof this paper to develop by empirical means a method whereby the relationshipof porosity to neutron-gamma deflection may be predicted for various bore holediameters. This relationship is applicable to the present commerciallyavailable neutron-gamma log run in open hole. Data available at present areinsufficient to establish similar correlations for cased holes. Through thedevelopment of such a correlation, the importance of the various factors whichinfluence the log become evident.

Neutron-Gamma Curve

The logging tool consists of a source of neutrons and a means of detectingand measuring gamma rays, the detector being shielded from the direct emissionfrom the source. The gamma rays reaching the detector have three sources oforigin:the natural gamma radiation emitted by the formations,induced gammaradiation resulting from neutron bombardment,gamma rays emitted by thesource and scattered by the formation.

It has been found that a neutron derived porosity correlation is best forshale-free formations. Under this condition the natural gamma ray radiation isquite low, and therefore, will be neglected in this work.

The induced gamma ray radiation resulting from neutron bombardment ispredominantly a function of the hydrogen atom concentration of the substancepenetrated. Due to the geometry of the presently used system, the neutron-gammacurve indicates low radioactivity opposite high hydrogen concentration and highradioactivity opposite low hydrogen concentration (Figs. 1 and 2). Having acurve which measures hydrogen atom concentration, it follows that if the matrixof the formation penetrated consists only of atoms other than hydrogen, and ifthe fluid filling the pores is either oil or water, the curve should be anindication of porosity (both oil and water have practically the same number ofhydrogen atoms per unit volume). The above criteria for a porosity correlationare fulfilled in clean sandstones and limestones in which the pore volume iscompletely filled with liquids (oil or water), but not in formations containingeither free gas or shale or both.

T.P. 3377
Use of the Automatic Free Piston in Oil Well Production Problems
Authors: McMurry E.D.
Published: April 2012

Introduction

Before discussing the use of the free piston, it may be well to explainbriefly the type of gas lift valves with which the tool is designed tofunction.

The gas lift valve is nothing more or less than a small back pressureregulator. Its construction consists of an outer housing covering a seamlessmetallic bellows in such a way as to form a sealed pressure vessel or pressuredome. To the bellows is attached a stem, and to this stem is attached a seatingmember. When the valve is run into the hole, a pre-determined pressure chargeis placed in the pressure dome. As shown in Fig. 1 the valve is furnished infour different major assemblies, to accomplish good results in different typesof wells.

The valve is mounted on a pup joint (Fig. 2-a); the complete assembly isentered into the tubing string at the desired location. Each valve is furnishedwith a reverse flow check valve (Fig. 2-b) to eliminate any back wash throughthe mechanism. Valve action is as follows:

At any time the casing pressure is allowed to exceed the pressure forceswithin the pressure dome of the valve, the valve simply opens and passes gasfrom the casing annulus into the tubing. When the casing pressure forces areallowed to bleed to a force less than the pressure force within the dome of thevalve, the valve closes.

With this type of construction, it is possible to open and close the valveor valves at will from the surface, through the medium of the gas pressure inthe casing annulus. The cycle of operation is governed by a time cycle motorvalve, commonly referred to as a gas lift intermitter or gas life surfacecontroller (Fig. 3). In actual practice, after the well is unloaded only onevalve is in operation… all other valves remain in the closed position. Onpre-determined time cycles, it is possible to open and close this operating valve at will, and to pass thedesired amount of gas through this valve whenever needed.

This method of gas lift is widely used and has been found to be veryefficient. However, it has long been known that even greater efficiency wouldbe obtained if it were possible to place a piston between the injected gas andthe fluid head. The free piston which will be discussed here was designed toaccomplish this end and has been found to do so with very satisfactoryresults.

T.P. 3583
Measuring and Interpreting High-Temperature Shear Strengths of Drilling Fluids
Authors: Watkins T.E. , Nelson M.D.
Published: April 2012

Introduction

Deeper drilling for oil is becoming more and more the rule rather than theexception. With deeper drilling come additional problems, perhaps the greatestbeing those brought on by the higher temperatures encountered down the hole, particularly in the Gulf Coast region of Texas and Louisiana. Temperaturegradients of the order of 1.8? to 2.0?F/100 ft are not unusual, and a gradientof 2.3?/100 ft is found in some areas of Texas. With a mean surface temperatureof 74?F, the following temperatures could be expected for a geothermal gradientof 2.0?F/100 ft: at 10,000 ft, 274?F, 12,000 ft, 314?F; 14,000 ft, 354?F; and16,000 ft, 394?F. Severe gelation of lime-base drilling fluid in wells thathave high bottom hole temperatures has become perhaps the most seriousdifficulty encountered in drilling under such conditions.

Lime-base drilling fluids have been very successfully and widely used in thedrilling of wells in the Gulf Coast region because of their inherent stabilitytoward contaminants, their ability to suppress the swelling dispersion ofbentonitic shales, and their ease of maintenance. The gradual recognition, during the past few years, that these muds were, in themselves, the cause ofmany difficulties experienced in drilling has led to widespread efforts by thedrilling industry to determine the reasons for the failure of these mud systems and to develop mud systems capable of performingsatisfactorily under high-temperature conditions.

Manifestations of High-Temperature Gelation

It is generally possible to recognize the symptoms of high-temperaturegelation early enough that advance predictions can be made of seriousdifficulties in mud control, and the useful life of the drilling fluids can beextended by proper treatment. Following is a list of the manifestations ofhigh-temperature gelation:The drill string ‘takes weight’ while going in the hole after a trip. Inearly stages of high-temperature gelation it is possible to notice a slightreduction in drill string weight as the drill pipe is lowered near the bottomof the hole.Excessive pump pressure is required to start the circulationof drilling fluid at or near the bottom of the hole when going back to bottomafter a trip.

T.P. 3638
Mile Six Pool - An Evaluation of Recovery Efficiency
Authors: Anders E.L.
Published: April 2012

The Mile Six pool is located on the La Brea-Parinas Concession ofInternational Petroleum Co., Ltd., in northwestern Peru on the west coast ofSouth America. The reservoir pressure in this pool has been maintained within200 psi of its initial value throughout its history, and gravity drainage hasplayed an important role in the production behavior. It has now produced 95 percent of its estimated ultimate recovery.

It is estimated that this interesting oil pool will ultimately produce 67per cent of the initial oil in place and that the resulting residual oilsaturation may be as low as 19 per cent of the pore volume (29 per cent of thehydrocarbon pore volume). An evaluation of reservoir rock and fluidcharacteristics and ultimate oil recovery is presented.

Introduction

This study of Mile Six pool was made to evaluate its performance accordingto latest available information. The production performance of this pool hasbeen discussed in various articles in the past, and the reported behavior hasbeen used as an example for application of computation procedures for gravitydrainage depletion and as an illustration of field behavior under gravitydrainage or expanding gas cap drive. There have been wide variations inreported values of initial oil in place, reservoir oil volume factor, connate-water saturation, volume of effective sand, and ultimate recoverybecause of the paucity of reliable basic data. These various factors have beendetermined as accurately as practicable with the latest available information, and this evaluation is presented herein. The production history of Mile Six isan excellent example of gravity drainage depletion with effective pressuremaintenance by gas injection.

General

Mile Six pool was discovered by cable-tool drilling in November, 1927, whenwell 1996 was completed in the Parinas sand. After slow development with cabletools and sporadic production, the pool was opened to continuous production inNovember, 1933, and development was completed with rotary rigs. Pressuremaintenance was started in December, 1933, by returning gas to up structurewells.

Most of the development was completed by 1937, but some additional wellswere drilled in the period 1939–1947, and several old wells were deepened. Atotal of 46 oil and gas wells and 4 dry holes were drilled on approximately7-acre spacing. Of the producers, 21 are now flowing, 2 are pumping, 4 are gasinput wells, 3 are abandoned, 1 is a gas well shut in, and 15 are shut inbecause of non-commercial production or high gas-oil ratio. The locations ofall wells are shown on the map of Fig. 1.

T.P. 3695
Application of Laboratory PVT Data to Reservoir Engineering Problems
Authors: Dodson C.R. , Goodwill D. , Mayer E.H.
Published: April 2012

The paper summarizes the historical background of thepressure-volume-temperature analyses of reservoir fluids, the errors involvedin both the sampling and testing of reservoir fluids, the type of informationrequired of a PVT determination, and the field conditions that limit theapplication of anyone analysis. Particular emphasis is placed on the necessityfor approximating as closely as possible the liberation sequence occurring inthe producing formation, flow string, and surface separators. A combineddifferential and flash or "composite" liberation is suggested as thebest means of approximating this liberation sequence.

Historical Background

Petroleum reservoir engineering commonly is considered to be one of thenewest fields of petroleum science, yet much work of a theoretical andintuitive nature was done many years before the modern techniques of reservoiranalyses were developed.

The period 1910–1924 saw considerable work in the field of reservoirbehavior done by the U. S. Bureau of Mines. This work, although entirelytheoretical, pointed out the importance of gas in the recovery of oil from thereservoir. The statement by J. O. Lewis that 20 per cent or less of theoil originally in place in a pool was recovered from the ground under uncurtailedproduction conditions caused some operators to re-examine and modify theirproduction methods. However, though these works showed methods of productionthat have subsequently resulted in greater oil recoveries, they in general wentunnoticed, even though there was a fear that the nation's petroleum resourceswere being exhausted.

The period 1924–1933 saw the industry take considerably more interest inreservoir behavior because of an unfounded fear of its inability to replace oilreserves, the possibility of government regulation, and the energy of one man, Henry L. Doherty. Doherty aroused heated discussions in the industry concerningconservation. To prove or disprove his theories the first experimental work onthe reservoir behavior of petroleum was undertaken. The papers of Dow andCalkin, Beecher and Parkhurst, and Mills and Heithecker are classics althoughtheir experimental procedures were crude. These papers proved that theproperties of petroleum in the reservoir are quite dissimilar to the propertiesmeasured at the well head. Gas dissolved in the oil phase was recognized ashaving considerable importance as had been predicted by the earliertheorists.

T.P. 3710
Injection of Human Bone Marrow and Mononuclear Cell Extract into Infarcted Mouse Hearts Results in Functional Improvement
Authors: Angeli Franca S , Zhang Yan , Sievers Richard , Jun Kristine , Yim Sarah , Boyle Andrew , Yeghiazarians Yerem
Published: April 2012

Background:

We have previously shown that mouse whole bone marrow cell (BMC) extract results in improvement of cardiac function and decreases scar size in a mouse model of myocardial infarction (MI), in the absence of intact cells. It is not clear if these results are translatable to extracts from human BMC (hBMC) or mononuclear cells (hMNC), which would have significant clinical implications.

Methods:

Male C57BL/6J (10-12 weeks old) mice were included in this study. MI was created by permanent ligation of the left anterior descending artery. Animals were randomized into three groups to receive ultrasound-guided myocardial injections with either hBMCs extract (n=6), hMNCs extract (n=8) or control with 0.5% bovine serum albumin (BSA) (n=7). Cardiac function was assessed by echocardiography at baseline, 2 and 28 days post-MI. Infarct size and vascularity was assessed at 28 days post-MI.

Results:

hBMC and hMNC extract preserve cardiac function and result in smaller scar size post-MI when compared with the control group.

Conclusions:

The current study for the first time reports that hBMC and hMNC extracts improve cardiac function post-MI in a mouse MI model. Further studies are necessary to fully address the potential clinical benefits of these therapies.
Application of the Chinese Posttraumatic Stress Disorder Checklist to Adolescent Earthquake Survivors in China
Authors: Wang Ruiming , Su Jie , Bi Xiaoyu , Wei Yubing , Mo Lei
Published: April 2012

We investigated the incidence of posttraumatic stress disorder among 2,448 middle-school students in Sichuan Province, China, soon after the Wenchuan earthquake occurred on May 12, 2008. We also tested the reliability and validity of a Chinese version of the Posttraumatic Stress Disorder
Checklist–Civilian Version (Weathers, Litz, Huska, & Keane, 1994) with this group. PTSD occurred more frequently among females compared with males, and among those exposed directly, indirectly, or not at all to the earthquake, the highest incidence of PTSD was among the group
exposed directly. Among 3 groups aged between 11 and 13, 14 and 15, and 16 and 18, the highest incidence of PTSD was in students aged 14 and 15. Compared with other groups those with the highest incidence of PTSD were students with low socioeconomic status, who witnessed the earthquake, had
heavy loss of their houses and other possessions, and whose family members were casualties. Factor analysis showed that the 3-factor model of the PCL-C had good construct validity. The internal consistency of Cronbach's alpha and split-half reliability was also satisfactory. Therefore, the
PCL-C was determined to be a reliable instrument to detect PTSD among Chinese adolescents exposed to the earthquake.
The way of perceiving ecological problems by citizens of Vojvodina: Presentation of empirical research
Authors: Pusic Ljubinko , Pajvancic-Cizelj Ana
Published: April 2012

The paper presents selected results of an empirical research about the
attitudes of Vojvodinian citizens towards ecological problems. Its starting
hypothesis is that the sensibility of citizens? attitudes towards ecological
problems is the crucial key to create participative model of decision-making
processes regarding environment. Research goals are descriptive and
exploratory: evaluating the general attitude towards ecological problems, and
checking their links with socio-demographic characteristics of respondents
and with the globalization of the consciousness about the environment. The
results of research show that respondents first recognize directly observable
ecological problems (pollution). The rest of respondents recognized
ecological problems which are necessarily mediated by global ecological
consciousness and by ideas that put mainly human beings in the center of
ecological issues (the lack of ecological consciousness). The respondents are
divided in determining the state/civil society as the possible source of
ecological problems, where most of them recognized the state institutions
(ecological legislation) as such. The respondents expressed a significant
level of non-anthropocentric values towards nature. The assumed link between
socio-demographic characteristics and reception of ecological problems was
not confirmed. It is shown that the attitude of Vojvodinian citizens towards
ecological problems is highly diversified. On one hand, this attitude
reflects an ecological consciousness, formed by the direct experience in the
local context; while, on the other hand, it reflects a consciousness formed
in the framework of globalized environmental discourse in ?networked
society?.
Emotions and social movements: The case of the animal rights and welfare movement in Serbia
Authors: Vukelic Jelisaveta
Published: April 2012

The aim of this paper is to explore the reasons behind the differences
between the organizations dealing with the animal protection and the other
environmental organizations. In that sense, the focus of our analysis is the
grassroots character of these organizations/associations as well as the
emotional basis of the member participation/mobilization. We draw upon the
data gathered through the interviews with the organizations' representatives
as well as through the analysis of other sources of information such as
websites, internet presentations and annual reports of animal protection
organizations. For the comparative purposes, we use a part of the material
gathered in the semi-structured interviews with the representatives of the
fifty Serbian environmental organizations.
Crystal plasticity: The Hamilton-Eshelby stress in terms of the metric in the intermediate configuration
Authors: Mariano Paolo
Published: April 2012

The Hamilton-Eshelby stress is a basic ingredient in the description of the
evolution of point, lines and bulk defects in solids. The link between the
Hamilton-Eshelby stress and the derivative of the free energy with respect
to the material metric in the plasticized intermediate configuration, in
large strain regime, is shown here. The result is a modified version of
Rosenfeld-Belinfante theorem in classical field theories. The origin of the
appearance of the Hamilton-Eshelby stress (the non-inertial part of the
energy-momentum tensor) in dissipative setting is also discussed by means of
the concept of relative power.
Coming to Terms with a Misinterpreted Past? Rethinking the Historical Antecedents of Germany's 1999 Citizenship Reform
Authors:   Andreas Fahrmeir
Published: April 2012

The article contends that the significance attributed to the 1999 citizenship reform in Germany is closely linked to a particular reading of the history of German citizenship policies. This reading, which remained dominant until the 1990s, assigned a crucial role for Germany's exclusionary citizenship policies to the law of descent, which seemed to be deeply ingrained in successive German states policies and practices from the nineteenth century on. Arguing that recent historiography on citizenship has called attention to the significant degree of variation between periods of openness and closure, as well as highlighting restrictive naturalization policies as a key ingredient of ethnic closure, the author contends that this focus was misplaced. Accordingly, the disappointing effects of a law that focused on the automatic transmission of citizenship while paying less attention to making voluntary transition to citizenship easier are not particularly surprising.
Germany's Citizenship Policy in Comparative Perspective
Authors: Howard Marc Morjé
Published: April 2012

This article puts the 1999 German Nationality Act into a comparative European perspective. By applying a common measure of the relative restrictiveness or inclusiveness of a country's citizenship policy to the countries of the EU-15 at two different time periods, it provides an analysis of change both within and across countries. From this perspective, Germany has clearly moved "up" from having the single most restrictive law before the 1999 reform to a more moderate policy today. Yet Germany's major "liberalizing change" was also tempered by a significant "restrictive backlash." The German case therefore provides support for a broader theoretical argument about the potential for mobilized anti-immigrant public opinion to nullify the liberalization that often occurs within the realm of elite politics.
Neoandrographolide Isolated from Leaves of Adhatoda vasica Nees
Authors: Al-Amin MD , Islam Md Monirul , Siddiqi M Mahboob Ali , Akter Shakila , Ahmed Shamim , Haque Mohammad Majedul , Sultana Nasim , Chowdhury AM Sarwaruddin
Published: April 2012

Neoandrographolide was isolated from the ethylacetate soluble fraction of the ethanol extract of the fresh leaves of Adhatoda vasica (Family: Acanthaceae). The crude extracts of hexane, ethylacetate and butanol soluble fractions of ethanol extract were subjected to antimicrobial screening and brine shrimp lethality bioassay. The ethylacetate crude extract exhibited moderate antimicrobial activity against most of the test organisms and also showed significant cytotoxicity having LC50 0.61 µg/ml.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10326Dhaka Univ. J. Sci. 60(1): 1-3, 2012 (January)
Sterols and Sterol Glucoside from Phyllanthus Species
Authors: Khatun Mahbuba , Billah Mirajum , Quader Md Abdul
Published: April 2012

Stigmasterol, stigmasta-5,22-dien-3-O-?-D-glucoside, ?-sitosterol, and sitosterol-3-O-?-D-glucoside were obtained from the organic solvent extractives of different parts of Phyllanthus species P. niruri, P. reticulatus, P. emblica, and P. acidus, through chromatographic separation. The structures of isolated compounds have been elucidated with the help of physical and spectroscopic studies. Medicinal importances of these species have also been discussed.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10327Dhaka Univ. J. Sci. 60(1): 5-10, 2012 (January)
Isolation of Quercetin-3-O-beta-d-glucopyranoside from the Leaves of Azadirachta Indica and Antimicrobial and Cytotoxic screening of the Crude Extracts
Authors: Islam Monirul , Al-Amin MD , Siddiqi M Mahboob Ali , Akter Shakila , Haque Mohammad Majedul , Sultana Nasim , Chowdhury AM Sarwaruddin
Published: April 2012

Quercetin-3-O-beta-D-glucopyranoside was isolated from the ethylacetate soluble fraction of the ethanol extract of the fresh leaves of Azadirachta indica (Family: Meliaceae). The crude extract of hexane, ethylacetate and butanol soluble fractions of this ethanol extract were subjected to antimicrobial screening and brine shrimp lethality bioassay. The ethylacetate crude extract exhibited moderate antimicrobial activity against most of the test organisms and also showed significant cytotoxicity having LC50 0.61 µg/ml.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10328Dhaka Univ. J. Sci. 60(1): 11-14, 2012 (January)
Application of Anion Exchange Resin for the Separation of Metals in Tert-butyl Alcohol-Water-Formic Acid Medium
Authors: Rahman Mohammad Arifur , Faruk Mohammad Omar , Alam AM Shafiqul
Published: April 2012

The use of tertiary butyl alcohol in admixture with formic acid for the selective elution of cations on the ion exchange resin Amberlite IRA-420 in Cl- form is investigated. The elution technique was coupled with absorption spectrometry and atomic absorption spectrophotometry. The distribution coefficients of metal ions were measured in tertiary butyl alcohol -water-formic acid mixture. By applying distribution co-efficient data, the metals from the mixtures have been separated one after another by eluting with tertiary butyl alcohol-water-formic acid solution of different compositions. The average recovery for all separations (n = 18) was within 94.6  98.2 % and the standard deviation for all data was ± 0.96. The developed analytical methodology was successfully applied for the separation and quantification of metal ions in the microgram range from the real samples collecting from natural water and industrial effluents using UV-Visible and AAS techniques.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10329  Dhaka Univ. J. Sci. 60(1): 15-20, 2012 (January)
Continuous Dependence of Fixed Points on Parameters and Initial Conditions
Authors: Islam Md Rezaul , Ferdousi Razina , Ali Md Showkat , Khan MR
Published: April 2012

The main purpose of the paper is to establish conditions for a continuous dependence of fixed points and an application to non-linear functional differential equation of neutral type have been made.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10330  Dhaka Univ. J. Sci. 60(1): 21-24, 2012 (January)
Investigations on Microstructural and Layer Disorder Parameters of Na-Montmorillonite-Glycine Intercalation Compounds
Authors: Khan Adnan Hossain , Bala Parimal , Rahman AFM Mustafizur , Nurnabi Mohammad
Published: April 2012

Glycine-Montmorillonite (Gly-MMT) composite has been synthesized through intercalation process using Na-Montmorillonite (Na- MMT) and glycine ethylester hydrochloride. Gly-MMT was employed for the synthesis of dipeptide (Gly-Gly-MMT). Microstructural parameters such as crystallite size, r.m.s. strain (1/2) and layer disorder parameters such as variation of interlayer spacing (g) and proportion of planes affected by such defects (?) of the samples have been calculated by X-ray line profile analysis. In comparison to Na-MMT the basal spacings (d001) of Gly-MMT and Gly-Gly-MMT were reduced by 2.4Å and 1.8Å respectively. The value of d001 of Gly-Gly-MMT (13.3 Å) suggests the monolayer orientation of dipeptide into interlayer spaces. It is also suggested that more homogeneity in the stacking of silicate layers is attained in Gly-Gly-MMT due to the increased chain length of the dipeptide and orientation in monolayer style.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10331Dhaka Univ. J. Sci. 60(1): 25-29, 2012 (January)
LSPIHT Algorithm for ECG Data Compression and Transmission for Telemedicine Applications
Authors: Zebin Tahmina , Farook Ekramul , Aman Syeda Zinath , Rafique Shahida
Published: April 2012

Medical image analysis and data compression are rapidly evolving fields with growing applications in healthcare services e.g. teleradiology, teleconsultation, e-health, telemedicine and statistical analysis of medical data. In this paper, a Layered Set Partitioning in Hierarchical Trees (LSPIHT) algorithm for medical data compression and transmission is presented. In the LSPIHT, the encoded bit streams are divided into a number of layers for transmission and reconstruction. Starting from the base layer, by accumulating bit streams up to different enhancement layers, medical data can be reconstructed with various signal-to-noise ratios (SNRs) and resolutions. Receivers with distinct specifications can then share the same source encoder to reduce the complexity of telecommunication networks for telemedicine applications. The algorithm is compared with other algorithms for encoding ECG data, and analysis shows that the LSPIHT attains better rate-distortion performance and low network complexity than other encoding techniques.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10332  Dhaka Univ. J. Sci. 60(1): 31-36, 2012 (January)
Performance Analysis of a PV Pump Harvesting Rain Water in the Drought Prone Area of Bangladesh
Authors: Reza Khan Mamun , Das Subrata , Mahmood Zahid Hasan
Published: April 2012

In this paper the performance of a PV driven water pump, without battery storage, for supplemental irrigation by harvesting rainwater is analyzed. A brushless DC motor is used in this work. The worst day, in terms of rainfall, of the month of July has been chosen for data collection. The variation of the flow rate as a function of the PV array power is found to be linear. Head loss is calculated and found greater at higher flow rate. Lower trend of the subsystem efficiency is observed with the increment of the array power. Considering the module efficiency of the manufacturer, the system efficiency is also calculated and found 3.2% as the highest. The amount of water lifted is found to be quite satisfactory for supplemental irrigation.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10333  Dhaka Univ. J. Sci. 60(1): 37-41, 2012 (January)
Photodegradation of Orange Green by Fe(III)Aqua Complex
Authors: Hossain Md Mufazzal , Rasel Md Rashedul Islam , Islam Md Safiqul
Published: April 2012

The photodegradation of orange green (OG) by excitation of Fe (III)-aqua complexes has been investigated under UV and solar light illumination. The rate of degradation has been found to be strongly influenced by the pH of the solution, initial concentration of Fe(III) and the nature of the light sources. The progress of removal of OG from solution has been monitored by recording the change of absorbance at ?max = 480 nm, (? = 1.27 × 104 L mol-1cm-1 at 30°C), with time. The pH has been varied from 1.2 to 3.5. The initial concentration of Fe (III) was between 9.0 × 10-4 mol L-1 and 2.4 × 10-3 mol L-1. The intensity of the UV artificial source was 14 Wm-2, whereas the average intensity of the solar light during the experiments was about 700 Wm-2. An optimistic result was obtained, when OG was irradiated by solar light. About 92% degradation of 1.5 × 104 mol L-1 OG solution has been done within 70 minutes by photodegradation using Fe(III)-aqua complex at pH 2.5 by UV light whereas about 86% degradation has been recorded by the solar light under the same conditions.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10334  Dhaka Univ. J. Sci. 60(1): 43-46 2012 (January)
Determinants and Status of Vaccination in Bangladesh
Authors: Afzal Nasrin , Zainab Begum
Published: April 2012

The identification of the characteristics that have an influence on the vaccination coverage of children and the determination of the pattern of such influence are very important since the government can reschedule the policy to immunize each and every child. This paper examines the factors that manipulate the vaccination coverage in terms of five major vaccines using the Bangladesh Demographic and Health Survey (BDHS)-2007 data. The results strongly suggest that mothers education and economic status play a vital role significantly in improving the vaccination coverage. Besides, Khulna and Rajshahi have higher whereas Sylhet and Chittagong have lower immunization coverage than Dhaka. In addition, mothers exposure to media (newspaper, TV or radio) also improves the status of coverage both in the rural and urban areas in Bangladesh.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10336  Dhaka Univ. J. Sci. 60(1): 47-51 2012 (January)
Demand for Institutional Delivery in Bangladesh: An Application of Household Production Function
Authors: Akanda Md Abdus Salam
Published: April 2012

Maternal and child health issues continue to be at the forefront of national and global health policies. Notwithstanding the national and global policy initiatives, maternal mortality continues to be on the ascendancy in developing countries. This paper investigates the determinants of institutional delivery among a cross section of Bangladeshi women. For appropriate policy targeting, it is imperative to investigate the factors that promote institutional delivery and those that retard it. Using discrete choice model, and controlling for other covariates, we found that, women from the richest income quintile, and those that have access to health information via television delivered at appropriate health institutions. Besides, place of residence, mothers education, wanted pregnancy, utilization of antenatal care services and number of health workers visiting time inter alia were found to be significant predictors of the demand for institutional and supervised delivery. The policy implication of this finding is that health education via television is more effective than print media. Secondly, government policies meant to create jobs and increase income levels are envisaged as proper policy instrument to induce the utilization of appropriate health services including institutional delivery. Thirdly, information, education and communication (IEC) programs are urgently needed to inform women about the cause and potential risk of maternal health complications as well as the significance of institutional delivery. Finally, the use of health inputs such as antenatal care during pregnancy should be encouraged.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10337  Dhaka Univ. J. Sci. 60(1): 53-59 2012 (January)
Linear Equation Method of Constructing Confounding Plan in pn - Factorial Experiment
Authors: Jalil MA
Published: April 2012

This article describes a linear equation method of designing simultaneous confounding of one or more factorial effects in pn - factorial experiment. It is demonstrated that it becomes easier to construct the design of simultaneous confounding of one or more factors in a pn - factorial experiment especially when the number of factors as well as the number of levels becomes larger. It is also discussed that such approach is very much convenient from the viewpoint of computation.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10338Dhaka Univ. J. Sci. 60(1): 61-64 2012 (January)
A Mathematical Model for the Alkylation of Phenol with Octanol-1
Authors: Saha Manoranjan , Hossain Md Kabir , Ashaduzzaman Md , Saha Dipti , Islam Shams Tania Afroza , Chowdhury AM Sarwaruddin , Kamruzzaman Mohammad
Published: April 2012

A 3-factor 2-level Yates pattern experimental design was used to develop a mathematical model for the alkylation of phenol with octanol-1 in the presence of sulphuric acid. A set of trials was planned with two replicates and the centre point trial with 4 replicates. Main effects as well as two- and three- factor interaction effects were statistically significant. The highest experimental yield was 79.5%. The experimental settings were temperature, 160ºC; molar ratio of phenol to octanol-1, 10:1; amount of 94% sulphuric acid, 8% by wt. of phenol; addition time, 2h and stirring time, 2h. Adequacy of the suggested model was checked. The difference between the experimental and estimated yield was negligible.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10339  Dhaka Univ. J. Sci. 60(1): 65-70 2012 (January)
Alkylation of Ethylbenzene with Cyclohexylchloride: A Statistical Study
Authors: Saha Manoranjan , Chakravarty Prashanta , Saha Dipti , Alam Md Zahangir , Tareque Mahmud Hasan , Alam Md Ashraful , Rana Ashequl Alam
Published: April 2012

A mathematical model was developed for the alkylation of ethylbenzene with cyclohexyl chloride in the presence of anhydrous aluminium chloride as a catalyst using the Yates Pattern experimental design. The variables chosen for the study were temperature, molar ratio of ethylbenzene to cyclohexyl choloride and amount of anhydrous aluminium chloride. The critical response was the yield of cyclohexylethylbenzene. Main effects as well as interaction effect of molar ratio of ethylbenzene to cyclohexyl chloride and amount of catalyst were statistically significant. The adequacy of the suggested model was checked.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10340  Dhaka Univ. J. Sci. 60(1): 71-76 2012 (January)
Investigation on Orange Peel: Derivatization of Isolated Cellulosic Material and Analysis of the Fatty Acids Composition
Authors: Islam Md Rabiul , Muslim Tanvir , Rahman Md Azizur
Published: April 2012

Isolation of cellulosic material from the waste material, orange (Citrus sinensis) peel has been carried out. The isolated cellulosic material has been converted into its acetate ester. The acetate derivative has been characterized by titrimetric method and IR spectra. The fatty acid composition of the orange peel has also analyzed by GLC. Successful conversion of agro-waste into its acetate derivative and the fatty acid composition suggest an alternative use of this waste material.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10341  Dhaka Univ. J. Sci. 60(1): 77-78 2012 (January)
Application of a Mathematical Model by Means of Experimental Design to Alkylation of o-Cresol with Cyclohexene
Authors: Kamruzzaman Mohammad , Rana Ashequl Alam , Alam Md Zahangir , Saha Manoranjan
Published: April 2012

Alkylation of o-cresol with cyclohexene in the presence of perchloric acid as catalyst was studied statistically with a three-factored experimental design. Factorial design was employed to study the effects of single factors and the effects of their interactions on the yield of alkylation. Reaction temperature, molar ratio of o-cresol to cyclohexene and amount of perchloric acid were considered as the major variables. A mathematical model was derived to calculate the predicted yield of alkylation of o-cresol with cyclohexene in the presence of perchloric acid under certain reaction conditions and cyclohexyl o-cresol was obtained in high yield. The adequacy of the suggested model was checked up and the discrepancies between the experimental and calculated values did not exceed 1.52%. An optimum yield (89.5%) of the product was obtained under the reaction conditions of a temperature of 140º C; a 6:1 molar ratio of ocresol to cyclohexene and a 5% by weight perchloric acid of o-cresol.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10342  Dhaka Univ. J. Sci. 60(1): 79-85 2012 (January)