bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Simple Methodology for Direct Estimation of Gas-in-Place and Reserves Using Rate-Time Data
Authors: Johnson N. L. , Currie S. M. , Ilk D. , Blasingame T. A. 
Published: April 2009

Abstract
Estimation of contacted gas-in-place/reserves in unconventional (low/ultra-low permeability) gas reservoirs is a problematic issue, and the uncertainty associated with the estimate is relatively higher. In this work we provide a robust methodology for estimating gas reserves in tight gas/shale gas systems based (primarily) on the use of an integrated approach which makes use of the following models: Semi-analytical formulation — "Quadratic" rate-cumulative relation type curve (Blasingame and Rushing [2005]).Empirical formulation — "power-law exponential" rate decline model (Ilk et al [2008a] and [2008b]).
A dimensionless quadratic rate-cumulative type curve is derived using the rate-cumulative relation proposed by Blasingame and Rushing (2005) and is given by: qD=1−αGpD+α2GpD2(where qD=qg/qgi,GpD=Gp/G,and  α=G/(qgi/Di)by definition)
A "reverse solution" for the α-parameter enables the analyst to establish the existence of boundary-dominated flow — directly from the data. Our experience using synthetic and field data suggests that, for the Blasingame and Rushing model, the α-parameter is equal to two (2) for full boundary-dominated flow.
We have also written the "power-law exponential rate decline relation" in dimensionless rate-time form and we employ the type-curve procedures for the analysis of a given set of rate-time data. The dimensionless power-law exponential rate decline relation is given as: qDd=exp[−D˜∞tDd−tDdn]
We have validated our analysis procedure for this model using a two numerical gas simulation cases and we have applied this procedure to several tight gas and shale gas cases. Our results show that when gas production data are analyzed using the integrated approach described in this work then the uncertainty in reserves estimates is reduced. Specifically, expressing the rate-cumulative production data functions in dimensionless forms provides a direct diagnostic of the boundary-dominated flow regime. Power law exponential rate decline type curves help the analyst to identify the features (character) in the rate data.
Calibrated Log Model and Reservoir Understanding Allows Accurate Prediction of Production and Improved Hydraulic-Fracturing Designs
Authors: Garcia Mariano , Mullen Michael J. , James Aaron 
Published: April 2009

Abstract
The Frontier formation in the Moxa Arch (Wyoming) is a complex, tight sandstone reservoir. As with any other tight formations, hydraulic-fracture stimulation is required to unlock the hydrocarbon reserves. This reservoir is also known for having high water and condensate production that seriously diminish the gas production, despite good reservoir quality, and can cause confusion when comparing the effectiveness of different stimulation techniques. A good understanding of reservoir characterization and production analysis is critical when comparing the effectiveness of different stimulation treatments across the field. This work addresses these topics by applying a systematic loop process that begins with reservoir evaluation, followed by completion design and production history analysis to identify the optimal treatment for each area in the field. The measure of success in this model was the accurate prediction of production using a reservoir flow-capacity model based on the parameters obtained from a calibrated log model specific to this reservoir and year-over-year production improvement. Once production capacity of the reservoir was known, an analysis allowed completion designs to be ranked by efficiency, from best to worst. Production-history matching provided additional information for a better understanding of the reservoir, as well as some other completion efficiencies. The results of this analysis were the key to identify necessary changes to improve fracture designs.
In this study, fifty one (51) wells that were completed before 2006 were used to generate the model to predict production. The model was later successfully tested using fourteen wells completed in 2007, where actual production matched model predictions and showed improvement over similar offset completions.
Different hydraulic-fracture treatment-design criteria were presented as a result of this study as optimized designs based on return on investment (ROI) for the Frontier formation. Each design criteria corresponds to specific areas of the field, where very clear and different fluid/gas ratios were identified.
Paradigm Change: Proppant Fracture Treatments in the Lower Green River Formation of the Altamont-Bluebell Field, Utah
Authors: Rajappa Bharath , Brown Devin L. , Lytle Denise M. 
Published: April 2009

Abstract
The Altamont-Bluebell field produces oil and gas from fractured, tight, lacustrine deposits. Initial field discovery is dated back to 1950. The main producing intervals are the Wasatch and the lower portion of the Green River formation. The lower Green River intervals are found at a depth of 8,000-10,500 feet and are the focus of this study.
Previous stimulation in the lower Green River formation mainly consisted of acid breakdown treatments. With the advent of better fracturing fluid additives and proppants, hydraulic fracturing has shown to be more effective when compared to acid stimulation treatments.
This work compares production data from over 20 hydraulically fractured recompletions done in the lower Green River formation. Fracture modeling with a fully functional 3D simulator is also presented to gain better insight into the fracture design. Finally, we present pitfalls and techniques to better stimulate the tight formations encountered.
Lightning induced atrial fibrillation
Authors: Dronacharya L , Poudel R 
Published: April 2009

Atrial fibrillation (AF) is a common arrhythmia that occurs in paroxysmal and persistent forms. It occurs in varied situations but lightning induced AF is extremely rare. Here is a case which reverted to sinus rhythm spontaneously. This 37-year-old man without any underlying heart disease had new onset AF after being struck by a lightning. Oral Metoprolol alone was given to control ventricular rate. Spontaneous reversion to sinus rhythm within 36 hours is in favor of new onset lightning induced AF. Key words: Lightning injuries, atrial fibrillation, ECG changes doi: 10.3126/kumj.v6i4.1747 Kathmandu University Medical Journal (2008), Vol. 6, No. 4, Issue 24, 5514-515
Subarachnoid hemorrhage and the distribution of drugs delivered into the cerebrospinal fluid
Authors: Pluta Ryszard M. , Butman John A. , Schatlo Bawarjan , Johnson Dennis L. , Oldfield Edward H. 
Published: April 2009

Object
Investigators in experimental and clinical studies have used the intrathecal route to deliver drugs to prevent or treat vasospasm. However, a clot near an artery or arteries after subarachnoid hemorrhage (SAH) may hamper distribution and limit the effects of intrathecally delivered compounds. In a primate model of right middle cerebral artery (MCA) SAH, the authors examined the distribution of Isovue-M 300 and 3% Evans blue after infusion into the cisterna magna CSF.

Methods
Ten cynomolgus monkeys were assigned to SAH and sham SAH surgery groups (5 in each group). Monkeys received CSF injections as long as 28 days after SAH and were killed 3 hours after the contrast/Evans blue injection. The authors assessed the distribution of contrast material on serial CT within 2 hours after contrast injection and during autopsy within 3 hours after Evans blue staining.

Results
Computed tomography cisternographies showed no contrast in the vicinity of the right MCA (p < 0.05 compared with left); the distribution of contrast surrounding the entire right cerebral hemisphere was substantially reduced. Postmortem analysis demonstrated much less Evans blue staining of the right hemisphere surface compared with the left. Furthermore, the Evans blue dye did not penetrate into the right sylvian fissure, which occurred surrounding the left MCA. The authors observed the same pattern of changes and differences in contrast distribution between SAH and sham SAH animals and between the right and the left hemispheres on Days 1, 3, 7, 14, 21, and 28 after SAH.

Conclusions
Intrathecal drug distribution is substantially limited by SAH. Thus, when using intrathecal drug delivery after SAH, vasoactive drugs are unlikely to reach the arteries that are at the highest risk of delayed cerebral vasospasm.
Biological Synthesis of Size-Controlled Cadmium Sulfide Nanoparticles Using ImmobilizedRhodobacter sphaeroides
Authors: Bai Hongjuan , Zhang Zhaoming , Guo Yu , Jia Wanli 
Published: April 2009

Abstract
Size-controlled cadmium sulfide nanoparticles were successfully synthesized by immobilizedRhodobacter sphaeroides in the study. The dynamic process that Cd2+was transported from solution into cell by livingR. sphaeroides was characterized by transmission electron microscopy (TEM). Culture time, as an important physiological parameter forR. sphaeroides growth, could significantly control the size of cadmium sulfide nanoparticles. TEM demonstrated that the average sizes of spherical cadmium sulfide nanoparticles were 2.3 ± 0.15, 6.8 ± 0.22, and 36.8 ± 0.25 nm at culture times of 36, 42, and 48 h, respectively. Also, the UV–vis and photoluminescence spectral analysis of cadmium sulfide nanoparticles were performed.
Synthesis, Characterization and Performance of Amine Modified Linseed Oil Fatty Amide Coatings
Authors: Alam Manawwer , Ray Alok R. , Ashraf S. M. , Ahmad Sharif 
Published: April 2009

AbstractA novel attempt has been made to develop ambient cured polyamine amide (PAA) resins by the condensation polymerization reaction of oil fatty amide diol (N,N‐bis 2‐hydroxy ethyl linseed oil fatty amide) (HELA) and o‐phenylene diamine, which was further modified by poly(styrene‐co‐maleic anhydride) (SMA) at different phr (parts per hundred part of resin) to get a series of PAA–SMA resins. The structural elucidation of HELA, PAA and PAA–SMA were carried out by FT‐IR, 1H‐NMR and 13C‐NMR spectroscopic techniques. The physico‐chemical and physico‐mechanical analyses were carried out by standard laboratory methods. Thermal analyses of these resins were accomplished by thermogravimetric analyses (TGA) and differential scanning calorimetry (DSC) techniques. Coatings of PAA–SMA were prepared on mild steel strips to evaluate their physico‐mechanical and chemical/corrosion resistance performance under various corrosive environments. It was found that among the PAA–SMA systems, PAA‐35 showed the best physico‐mechanical and corrosion resistance performance. Thermal studies reveal that the coatings can be safely used up to 305 °C.
Purification of GLA‐Triglycerides from Evening Primrose Oil by Gravimetric Column Chromatography
Authors: Rincón‐Cervera M. A. , Rodríguez‐García I. , Guil‐Guerrero J. L. 
Published: April 2009

AbstractGravimetric normal‐phase silver ion–silica gel column chromatography has been used for the novel application of purification of GLA‐containing triglycerides (GLA‐TGs) from evening primrose seed oil (EPO). Gradient elution with increasing polarity enabled separation of valuable TG species containing γ‐linolenic acid (GLA, 18:3n‐6). Enzymatic hydrolysis revealed the distribution of fatty acids (FAs) in the isolated TG species, with GLA in the sn‐2 position in different percentages, depending on the degree of unsaturation. A novelty of this work was the successful use of the procedure to improve the purification of raw GLA species from EPO up to preparative scale, thus enabling use of this methodology for industrial purposes.
Smad2 isoforms are differentially expressed during mouse brain development and aging
Authors: Ueberham Uwe , Lange Peggy , Ueberham Elke , Brückner Martina K. , Hartlage‐Rübsamen Maike , Pannicke Thomas , Rohn Susanne , Cross Michael , Arendt Thomas 
Published: April 2009

AbstractSmad2 and Smad3 are central molecules of the TGFβ and activin receptor complex mediated intracellular signaling pathway. They function as important transcription factors playing essential roles in brain development. Interestingly they are also known to be involved in the pathogenesis of various neurological disorders (including Alzheimer's disease). Due to structural differences in the N‐terminal Mad homology domain 1, Smad2 and Smad3 differ in their ability to bind DNA directly. A splice form of Smad2 lacking exon3, Smad2(Δexon3), assumes features of Smad3, in that it can directly bind to DNA resulting in a functional hybrid of Smad2 and Smad3 properties. There is very little information available on the expression of Smad2 isoforms in the brain. We report here that Smad2(Δexon3) is the most abundant of the two Smad2 isoforms in mouse brain and that Smad expression pattern alters during development and aging. Neuronal expression of Smad2(Δexon3) was confirmed by a single‐cell PCR approach. Moreover, Smad2(Δexon3) predominates in the nuclear fraction of neurons, suggesting special function during brain differentiation. Our data indicate that there may be a specific role for Smad2(Δexon3) in neurons.
Evidence of NAO control on subsurface ice accumulation in a 1200 yr old cave-ice sequence, St. Livres ice cave, Switzerland
Authors: Stoffel Markus , Luetscher Marc , Bollschweiler Michelle , Schlatter Frédéric 
Published: April 2009

AbstractMid-latitude ice caves are assumed to be highly sensitive to climatic changes and thus represent a potentially interesting environmental archive. Establishing a precise chronology is, however, a prerequisite for the understanding of processes driving the cave-ice mass balance and thus allows a paleoenvironmental interpretation. At St. Livres ice cave (Jura Mountains, Switzerland), subfossil trees and organic material are abundant in the cave-ice deposit, therefore allowing the dating of individual ice layers. The dendrochronological analysis of 45 subfossil samples of Norway spruce (Picea abies (L.) Karst.) from the overhanging front of the ice outcrop as well as the dating of seven wood samples with 14C dating allowed for a reconstruction of the St. Livres cave-ice sequence and for the determination of periods of ice accumulation and ablation. Results suggest a maximal age of 1200 ± 50 14C yr BP for the observed ice sequence and indicate the presence of four major deposition gaps dated to the 14th, 15th, mid-19th and late 19th century, which can be related with periods of positive North Atlantic Oscillation anomalies (NAO+) over the winter half-year and/or anthropogenic cave-ice abstraction. Similarly, there is evidence that periods of cave-ice accumulation as observed between AD 1877–1900 and AD 1393–1415 would correspond with phases of negative NAO indices. Cave ice represents therefore an original climate archive for the winter half-year and is complementary to other continental proxies recording preferentially summer conditions (e.g., tree rings, varves).
Elliptic differential operators and diffusion processes
Authors: Bauer Heinz 
Published: April 2009

This article develops survey lectures for general mathematical audiences which the author delivered at the 27th Annual Meeting of the Australian Mathematical Society at the University of Queensland, 1983, and at the 10th Austrian Congress of Mathematicians in Innsbruck, 1981. The central theme of these lectures was the use of probabilistic methods in the study of linear elliptic-parabolic differential equations of second order.The starting point will be an orientative discussion of the role of Brownian motion in classical potential theory. It will then be discussed that, given an elliptic-parabolic differential operator L of a certain type, there exists a uniquely determined diffusion process which is linked with L formally in the same way in which Brownian motion is linked with the Laplace operator. The fundamental results of K. Itô, D.W.Stroock and S.R.S. Varadhan will be in the centre of this part of the paper. We will then proceed to the discussion of more refined problems of the same type for differentiable manifolds. A glimpse at stochastic Riemannian geometry will then close our tour d'horizon.
A chain rule for differentiation with applications to multivariate hermite polynomials
Authors: Withers C. S. 
Published: April 2009

A chain rule is given for differentiating a multivariate function of a multivariate function. In the univariate case this chain rule reduces to Faa de Bruno's formula.Using this, a simple procedure is given to obtain the rth order multivariate Hermite polynomial from the rth order univariate Hermite polynomial.
K-Fold symmetric starlike univalent functions
Authors: Anh V. V. 
Published: April 2009

This paper establishes the radius of convexity, distortion and covering theorems for the classwhere−1 ≤ B < A ≤ 1, w(0) = 0, |w (z)| < 1 in the unit disc.
Coefficient bounds for functions in are also derived.
On bounds for the Lipschitz constant of the remainder in polynomial approximation
Authors: Elliott David 
Published: April 2009

Suppose f is a function possessing a kth order derivative, the derivative being Lipschitz continuous of order α, 0 < α ≤ 1, on [−1, 1]. Let Pn be a polynomial of degree ≤ n approximating to f on [−1,1] such that if rn = f − Pn then ∥rn∥∞ ≤ An−k−a Definewhere 0 < β ≤ 1. Upper bounds are obtained for Mn(β) when k ≥ 1 thereby generalizing results previously given for functions which are only Lipschitz continuous on [−1,1].
On a property of ideals of differentiable functions
Authors: Bruno Oscar P. 
Published: April 2009

Let J ⊆ C∞ (Rn) be any ideal. Since a function of the variables t̄ = (t1,…,tn) is a function of the variables which does not depend on x̄, we have J ⊆ C∞ (IRn+P). Of course, J is not an ideal of C∞ (IRn+P), but it generates an ideal that we call . Consider the following statement (1) on J: “Given any if and only if for every fixed .In this paper we show that statement (1) holds for a large class of finitely generated ideals although not for all of them. We say that ideals satisfying statement (1) have line determined extensions. We characterize these ideals to be closed ideals J(t̄) (in the sense of Whitney) such that for all p ∈ ℕ, the ideal is also closed. Finally, some non-trivial examples are developed.
Periodic solutions of quasilinear non-autonomous systems with impulses
Authors: Hristova S.G. , Bainov D.D. 
Published: April 2009

The paper considers a system of differential equations with impulse perturbations at fixed moments in time of the formwhere x ∈ Rn, ε is a small parameter,Sufficient conditions are found for the existence of the periodic solution of the given system in the critical and non-critical cases.
Lebesgue constants for double Hausdorff means
Authors: Ustina F. 
Published: April 2009

As is well known, the divergence of the set of constants known as the Lebesgue constants corresponding to a particular method of summability implies the existence of a continuous, periodic function whose Fourier series, summed by the method, diverges at a point, and of another such function the sums of whose Fourier series converge everywhere but not uniformly in the neighborhood of some point.In 1961, Lorch and Newman established that if L(n; g) is the nth Lebesgue constant for the Hausdorff summability method corresponding to the weight function g(u), thenwherewhere the summation is taken over the jump discontinuities {εk} of g(u) and M{f(u)} denotes the mean value of the almost periodic function f(u).In this paper, a partial extension of this result to the two dimensional analogue is obtained. This extension is summarized in Theorem 1.3.
Certain integrals for classes of p-valent meromorphic functions
Authors: Kumar Vinod , Shukla S.L. 
Published: April 2009

In this paper we introduce two classes, namely Γp(m, M) and Σp(m, M), of functionsregular and p-valent in D − {0} where D = {z : |z| < 1}. We show that, for suitable choices of real constants α, β and γ, the integral operators of the formmap into , where is the class of p-valent meromorphically starlike functions of order ρ, 0 ≤ ρ < 1. For the classes Γp(m, M) and Σp(m, M), we obtain class preserving integral operators of the formwith suitable restrictions on real constants α and γ.Our results generalize almost all known results obtained so far in this direction.
Cardinality of discrete subsets of a topological space
Authors: Gauld David B. , Vamanamurthy M.K. 
Published: April 2009

In this paper we prove two results relating the cardinalities of discrete subsets to those of dense subsets of a topological space. In particular, we show that(1) closed discrete subsets of separable normal spaces are countable, and(2) discrete subsets of separable regular spaces have cardinalities at most that of the continuum.
Average distances in compact connected spaces
Authors: Yost David 
Published: April 2009

We give a simple proof of the fact that compact, connected topological spaces have the “average distance property”. For a metric space (X, d), this asserts the existence of a unique number a = a(X) such that, given finitely many points x1, …, xn ∈ X, then there is some y ∈ X withWe examine the possible values of a(X) , for subsets of finite dimensional normed spaces. For example, if diam(X) denotes the diameter of some compact, convex set in a euclidean space, then a(X) ≤ diam(X)/√2 . On the other hand, a(X)/diam(X) can be arbitrarily close to 1 , for non-convex sets in euclidean spaces of sufficiently large dimension.
On a certain kind of reducible rational fractions
Authors: Lewin Mordechai 
Published: April 2009

The rational fractiona, c, p, q positive integers, reduces to a polynomial under conditions specified in a result of Grosswald who also stated necessary and sufficient conditions for all the coefficients to tie nonnegative.This last result is given a different proof using lemmas interesting in themselves.The method of proof is used in order to give necessary and sufficient conditions for the positive coefficients to be equal to one. For a < 2pq, a = αp + βq, α, β nonnegative integers, c > 1, the exact positions of the nonzero coefficients are established. Also a necessary and sufficient condition for the number of vanishing coefficients to be minimal is given.
The completion of a topological group
Authors: Nummela Eric C. 
Published: April 2009

During the 1920's and 30's, two distinct theories of “completions” for topological spaces were being developed: the French school of mathematics was describing the familiar notion of “complete relative to a uniformity”, and the Russian school the less well-known idea of “absolutely closed”. The two agree precisely for compact spaces.The first part of this article describes these two notions of completeness; the remainder is a presentation of the interesting, but apparently unrecorded, fact that the two ideas coincide when put in the context of topological groups.