bluuebunny/crossref_metadata_2025 huggingface dataset:
Developing Young Exploration and Production Professionals To Solve the "Big Crew Change"
Authors: Tealdi L. , Kreft E. , Donachie J. M.
Published: December 2007

Analysis of SPE Membership age distribution reveals under-representation of those younger than 35 years and the average age approaching 50 years. Assuming this is representative of the global E &P industry, a large portion of the current industry workforce will retire within the next 10 years. It follows that attracting and retaining young people is a key strategy today for tomorrow's successes.

The "big crew change" indicates the risk of a significant reduction of available E &P expertise available. Meanwhile, producing oil and gas fields are maturing and new finds are more complex to locate and develop. This means personnel will need to develop a larger cross-disciplinary skills base with each individual skill advancing to address the increasing complexity of operation. The development of young people should be carefully planned within E &P companies, since young professionals represent a vital asset and a major source of competitive advantage in the future.

Maintaining young professionals' motivation and favouring their pro-activeness should achieve continuous growth, excellent performance and dedication to the industry. Existing E &P expertise plays a crucial role. Experienced personnel need to be actively involved in mentoring-coaching programs to facilitate and drive skills' development in newer industry entrants. Organizations who do not pursue an agenda for speedy and comprehensive professional and technical development of their young employees risk their ability to follow future market trends. Such organizations will likely fail to maintain competitive innovation and change.

The paper describes the importance of young professionals in the E &P industry today, offering suggestions on the delicate theme of retention, motivation, performance, empowerment, and specialist versus cross-discipline skills development. Results from various international surveys of the comments of both young, and experienced, professionals are presented.
Increasing Confidence in Production Forecasting Through Risk-Based Integrated Asset Modelling, Captain Field Case Study
Authors: Wickens L. M. , Energy RPS , Jonge G. De
Published: December 2007

To assist in the probabilistic forecasting and decision making process for their Captain North Sea heavy oil asset, Chevron has developed an Integrated Asset Model (IAM). This model includes probabilistic predictions of facilities performance and production, enabling decision risk analysis for strategic and operational decisions. The IAM includes risk-based oil, gas and water production forecasts for the Captain Field and cash flows. These forecasts take full account of facilities constraints and uncertainties in reservoir and operational parameters through links to decision risk analysis software. This paper describes the novel approach used and model application.

Given the presence of multiple reservoir models, multiple PVT descriptions, three-phase flow, and a variety of well types from infill to ‘new field’, the best source of reservoir performance profiles for each well was the in-house Eclipse™ reservoir simulation models. The production profiles for each well are represented by a rate versus cumulative production curve. A particular feature of the IAM is its ability to automatically capture the output of individual Eclipse™ data sets. The results of the simulation models are combined into a single spreadsheet model. This is of particular importance as it enables the effect of facility throughput limitations on gas and water production to be readily assessed. In particular it provides the ability to choke back individual wells on a priority basis from any of the wells in the separate simulations.

A key feature of the model is the ability to investigate new scenarios without the need to run additional Eclipse™ simulations. Validation of this feature is demonstrated.

An example of the model's application to a Captain development decision on whether to proceed with a well workover will be discussed.
New Downhole Electromechanical Service Tool Advancements Provide Increased Integrity in HP/HT Environments
Authors: Foster J. , McConnell R. A. , Moore D. W.
Published: December 2007

During the 1990’s, a battery-powered electro-mechanical downhole service tool used to set/retrieve various pressure containment devices in the wellbore was introduced to the industry. These electro-mechanical actuators are capable of generating high but controllable axial forces at the point of application without relying on surface mechanical manipulations or explosive devices. This capability eliminates most of the logistical special safety considerations inherent with explosive actuators. Since the self-powered tool is independent of the surface machinery, another advantage is that it is possible to reduce the surface footprint for more efficient logistical management.

The electro-mechanical service tools are compatible with conventional slickline intervention methods and provide a practical alternative for explosive and hydrostatic setting tools. (See Fig. 1). This tool has also added significant cased-hole functionality to slickline intervention methods. While the first generation of the electro-mechanical service tools met the majority of conditions needed in the 1990’s, their functionality could not meet some of the operating requirements needed by the deeper, higher pressure fields being produced today.

This paper will describe a new tool system that provides the advantages of the standard downhole power unit (DPU®) system but overcomes the temperature limitations imposed by the more demanding downhole environments in today’s oilfield. The control logic, power management, and power delivery methods used to develop a functional and reliable electro-mechanical actuator for high-temperature/high pressure applications will be discussed. Also outlined is the environmental test program representing real world conditions that was used to validate its reliability. Finally, case histories will be presented.
A Rigorous Well Model To Optimize Production From Intelligent Wells and Establish the Back-Allocation Algorithm
Authors: Graf T. , Graf S. P. , Evbomoen P. , Umadia C.
Published: December 2007

The installation of intelligent wells to improve the economics of production is now common practice. These wells allow the access to marginal reservoirs, for which dedicated production might not be economic, and also accelerate the recovery. Sensors, flow-control and other devices can be used to manage the production from the commingled reservoirs and optimize the recovery.

Traditional methods for production optimization and back-allocation of complex well configurations, such as nodal analysis, work only for a static problem. They cannot account for the dynamic changes that occur in time in the connected system of reservoirs and wellbore. Once multiphase flow occurs, both the change of the fluid mobility in the reservoir and the change of the choke performance cannot be correctly addressed. Moreover, the large number of uncertainties from reservoir to wellbore behavior that influence the performance of those advanced wells cannot be accurately dealt with using traditional approaches.

A process is introduced that creates the most accurate well model of an intelligent completion accounting for all effects influencing the pressure behavior in the wellbore and in the reservoir. This model is used for optimization over all static and dynamic uncertainties to derive an interaction strategy with the intelligent well that maximizes oil production. Furthermore, the back-allocation algorithm is calibrated and trained on the proxy model of the well model.
The Influence of Oxidative Damage on Viscosity of Seminal Fluid in Infertile Men
Authors: Aydemir Birsen , Onaran Ilhan , Kiziler Ali Riza , Alici Bulent , Akyolcu Mehmet Can
Published: December 2007

ABSTRACT: Increased oxidative damage has been suggested to play an important role in the viscosity changes of blood. However, changes in levels of oxidative damage products in semen and their relationship to seminal fluid viscosity are unknown. The aim of our study was to investigate whether oxidative damage was associated with seminal plasma viscosity in infertile subjects. The levels of malondialdehyde, and protein carbonyls were measured in sperm and seminal plasma from 102 individuals, including 60 infertile patients. Seminal fluid viscosity and semen viscosity were studied by use of capillary viscometer and glass pipettes, respectively. Significantly higher levels of oxidative stress and damage markers were found in subfertile subjects compared with the control subjects. The seminal fluid viscosities of patients were found to be significantly higher, although all of the control and patient subjects had normal viscoelasticity when semen samples were assessed according to World Health Organization guidelines. From Pearson correlation analysis, there were significant positive correlations between seminal fluid viscosity and seminal malondialdehyde and carbonyl levels in infertile males (r = .676, P < .01; r = .276, P < .05, respectively). Our results suggest that increased oxidative damage might be a factor for hyperviscosity of seminal plasma in infertile males.
Darwin's Dilemma: Science in the Public Forum
Authors: Johnson-Sheehan Richard , Morgan Lawrence
Published: December 2007

This article explores the basis of the public debate between Darwinian evolution and creationism. Using dramatic analysis, we show that the source for the debate is due to what we call “Darwin's Dilemma,” which is found in Darwin's Origin of Species. In the Origin, Darwin extends the mechanistic metaphor featured in Enlightenment science by devising the concept of “natural selection.” In the process, however, he also ascribes a motive to nature, which moves his theory outside the boundaries of Enlightenment science. We show that he is aware of this dilemma in his theory, and that he tries to pass it off as a metaphorical maneuver for the sake of brevity. Darwin's inability to resolve this dilemma, however, opens the door for purveyors of creationism and intelligent design. Indeed, much of the debate today over Darwinian evolution still pivots on our inability to come to terms with Darwin's dilemma.
Dam Visuals: The Changing Visual Argument for the Glen Canyon Dam
Authors: Ross Derek G.
Published: December 2007

Arguments manifest in scientific visuals through graphic representation, content placement, and overall document structure. These arguments, designed to influence public perception, change over time in relation to sociopolitical climate. Analysis of a series of documents constructed deliberately to influence perception can help to determine patterns of argumentation and perceived exigencies. In this article, four self-guided tour brochures produced for distribution to visitors to the Glen Canyon Dam in 1977, 1984, 1990, and 1993 are analyzed in order to identify rhetorical strategies designed to influence public perceptions of the dam site, and examine how public perception of the dam, and related argumentation, is structured by sociopolitical climate.
Foreign Direct Investment in the Changing Business Environment of the European Union's New Member States
Authors: Witkowska Janina
Published: December 2007

Business environment is one of the location factors taken into account by investors while investing abroad. This paper focuses on the relationship between changes in business environments in the new Member States of the European Union (EU) and foreign direct investors' behavior. The analysis concentrates on Central and Eastern European (CEE) countries, with special reference to Poland, the Czech Republic, Hungary and Slovakia. The EU policies and the national incentive-based FDI policies are two driving forces influencing business environment in the new Member States. All the adjustments to the EU requirements reshape conditions for doing business in the new Member States and lead to the improvement of so called economies' 'fundamentals'. The national FDI policies could be treated as a factor disturbing these long term processes and changing economic choices of the established and potential investors. The statistical data on FDI inward stock and annual FDI flows confirm the positive reaction of foreign investors to the changes taking place throughout Central and Eastern Europe. Some data, however, confirm also that there is intense incentive-based competition and a kind of bidding war between them in order to attract foreign investors.
The "Deeper" and the "Wider" EU Strategies of Trade Integration: An Empirical Evaluation of EU Common Commercial Policy Effects
Authors: De Santis Roberta , Vicarelli Claudio
Published: December 2007

Since the post war period, the EU Common Commercial Policy (CCP) has moved in two directions mainly through Preferential Trade agreements (PTAs): a "deeper" (internal) trade integration process intended to reinforce trade relations among European countries (i.e. Custom Union, Single Market, European Monetary Union, Enlargement Process), and a "wider" (external) integration process intended to reinforce trade relations with third countries.

Surprisingly, there are very few empirical studies in the literature which specifically quantify the effects of the overall EU PTAs on the European countries’ trade flows. This paper seeks to fill this gap by conducting an empirical investigation on whether and how the CCP had a significant impact on European countries' imports. It adopts an extended version of the gravity model. In line with recent studies, it uses a Hausman Taylor estimator, controls for heterogeneity and includes a set of variables to proxy for the "multilateral trade resistance index"

According to our results, the EU "free trade area" has been a successful experiment in trade liberalisation. However, the positive and significant coefficient of PTAs signed by the EU with third countries may somehow have limited the occurrence of trade diversion effects. Indeed, the coefficient of the trade diversion dummy is significant but relatively small.
Aggregate Gains of International Diversification through Foreign Direct Investment: An Inquiry into the Moderation of U.S. Business Cycles
Authors: San Vicente Portes Luis
Published: December 2007

Over the last 20 years the U.S. economy has experienced a strong reduction in the volatility of GDP growth. This paper documents and models the rapid growth of multinational corporations as a source of gradual decline in output and investment volatility. The paper introduces internationally diversified multinational firms into the financial accelerator framework; where international operations provide multinational firms with smoother paths of net worth that result in less volatile financing costs, investment and production. Model simulations suggest that larger multinational corporations can account for up to a 19 percent and 27 percent decline in output and investment volatility, respectively.
A Causal Analysis of the R&D Interactions between the EU and the US
Authors: Atukeren Erdal
Published: December 2007

This paper examines the relationships between the aggregate R&D activities of the EU and the US using multivariate Granger-causality tests. Our estimation results indicate that the EU reacts positively to increases in R&D productivity in the US. On the other hand, R&D activity in the EU is a direct Granger-cause of both R&D and labour productivity in the US, and the effects are negative. It was shown in the literature that the US reacts submissively to successful Japanese R&D. We extend the literature by demonstrating that the US also reacts submissively to increased R&D effort in the EU.
Does AFTA Create or Divert Trade?
Authors: Cabalu Helen , Alfonso Cristina
Published: December 2007

In this article the changes in trade patterns introduced by the ASEAN Free Trade Area (AFTA) are examined. Variation in growth trends and the shift-and-share methodology are used to identify the impact of trade liberalization under AFTA on intra- and extra-regional commodity trade. Data at the commodity level are used and the results indicate that AFTA had trade creation effects, with little evidence of trade diversion.
Ethanol: No Free Lunch
Authors: Schmitz Andrew , Moss Charles B. , Schmitz Troy G.
Published: December 2007

The sharp rise in energy prices in the 1980s triggered a strong interest in the production of ethanol as an additional energy component. Economists are divided as to the payoffs from ethanol derived corn in part because of the complex interrelationship between energy produced from ethanol and energy from fossil fuels. Using a welfare economic framework, we calculate that there can be treasury savings from ethanol using tax credits as these subsidies can be smaller than direct payments to corn farmers which are essentially eliminated from the expansion of ethanol. Also, to the extent that ethanol dampens fuel prices there can be a net welfare gain from ethanol production in the presence of ethanol subsidies.
Biofuels Policies in Asian Countries: Impact of the Expanded Biofuels Programs on World Agricultural Markets
Authors: Koizumi Tatsuji , Ohga Keiji
Published: December 2007

The governments of Asian countries are promoting biofuels programs to deal with energy security and environmental problems, and to increase farm income. However, securing raw materials for biofuels is a crucial problem, because these raw materials comprise various agricultural products which are used as food sources in Asian countries. Increasing biofuel consumption is exacerbating this problem. To address it, the governments of Asian countries are working on biofuel programs which will not compete with food security. Most of the Asian countries are food-importing countries. Increasing food prices, due to competition, could lead to social unrest. It is expected that the introduction and development of second-generation biofuels can mitigate the competition between food and energy. As various countries develop second-generation biofuels, international cooperation is needed to maximize such development in Asia and other regions. Establishing international cooperation to develop second-generation biofuels is urgently needed in Asian countries.
Fueling the Automobile: An Economic Exploration of Early Adoption of Gasoline over Ethanol
Authors: Dimitri Carolyn , Effland Anne
Published: December 2007

When the automobile was developed near the beginning of the last century, it was the relatively new fuel gasoline, not the familiar ethanol that became the fuel of choice. We examine the intersections of the early development of the automobile and the petroleum industry and consider the state of the agriculture sector during the same period. Through this process, we find a series of influences, such as relative prices and alternative markets, that help to explain how in the early years of automobile development, gasoline won out over the equally likely technical alternative ethanol. We also examine the industrial relations in the automobile industry that seem to have influenced the later adoption of leaded gasoline, rather than ethanol, as a solution to the problem of engine knock.
Technical and Financial Feasibility Analysis of Distributed Bioprocessing Using Regional Biomass Pre-Processing Centers
Authors: Carolan Joseph E. , Joshi Satish V. , Dale Bruce E.
Published: December 2007

Research indicates that large biorefineries capable of handling 5000-10000MT of biomass per day are necessary to achieve process economies. However, such large biorefineries also entail increased costs of biomass transportation and storage, high transaction costs of contracting with a large number of farmers for biomass supply, potential market power issues, and local environmental impacts. We propose a network of regional biomass preprocessing centers (RBPC) that form an extended biomass supply chain feeding into a biorefinery, as a way to address these issues. The RBPC, in its mature form, is conceptualized as a flexible processing facility capable of pre-treating and converting biomass into appropriate feedstocks for a variety of final products such as fuels, chemicals, electricity, and animal feeds. We evaluate the technical and financial feasibility of a simple RBPC that uses ammonia fiber expansion pretreatment process and produces animal feed along with biorefinery feedstock.
Microwave Assisted Regeneration of Zeolite
Authors: Polaert Isabelle , Ledoux Alain , Estel Lionel , Huyghe Raphael , Thomas Michel
Published: December 2007

This paper presents an experimental study on zeolite NaX dehydration under microwave irradiation at a laboratory scale. Dehydration rates vary linearly with the absorbed power and show no influence with the purge gas flowrate. A pulsed mode of irradiation enhances dehydration due to higher temperatures reached and improved mass transport rates. A thermal balance model is developed in order to assess the maximum temperature reached in the adsorbent bed and the use of the dissipated energy inside the solid is discussed. From these results, this paper evaluates the economic interest in a microwave regeneration process and discusses the technical feasibility at an industrial scale.
Modeling of a SMB-type Reactor for Hydrogen Storage by Iron Oxide with a Reversible Reaction Mechanism
Authors: Imanishi Hironori , Maeda Akira , Maegawa Takeyuki , Matsuno Shigeru , Aida Takashi
Published: December 2007

Steam oxidation of iron metal which is the reverse reaction of the reduction of iron oxides as a hydrogen storage material was conducted under the condition of 673K with varied partial pressures of water vapor. The kinetic model of the steam oxidation of iron metal was expressed as the ordinary shrinking-core model with film diffusion control by experimental data obtained from thermogravimetric measurement. The apparent rate constant of steam oxidation was expressed as the Langmuir type equation against the partial pressure of water vapor. A model of a simulated moving bed-type reactor to solve the problem of over-reduction of materials was made. In our previous work (forthcoming), the kinetic model of the reduction of iron oxide with hydrogen was expressed as a shrinking-core model with reaction control, and the modeling of a simulated moving bed-type reactor was made with an irreversible reaction model. In this work, the modeling of a simulated moving bed-type reactor was achieved with the model of a reversible reaction consisting of reduction rate and oxidation rate.
Hydrogenation of Sunflower Oil over Bimetallic Supported Catalysts on Mesostructured Silica Material
Authors: Belkacemi Khaled , Kemache Nassima , Hamoudi Safia , Arul Joseph
Published: December 2007

Hydrogenation of vegetable oils using stable catalysts with satisfactory activity and selectivity as well as very low trans fatty acid (TFA) and saturated fatty acid (SFA) production is a challenging task. It is known that unhealthy TFA formation is the result of positional and conjugative isomerization side-reactions occurring during hydrogenation. From this standpoint, it is possible to formulate active, selective and stable catalysts which would minimize the production of TFA and SFA.Monometallic Pd and bimetallic Pd-Me (Me=Mo, Ni, Co, Ru, and Sr,) highly dispersed on mesostructured SBA-silica material with pore size ranging from 6 to 7 nm, BET-specific surface of 800-900 m²/g, and metal nominal total loading up to 1.0 % w/w, were comparatively investigated as catalysts for lowering the unhealthy trans (TFA) and saturated (SFA) fatty acids and maximizing the highly health-beneficial cis-monoenes production during the hydrogenation of sunflower oil at 110 oC under hydrogen pressure of 5 atm.The Pd-catalyst at nominal metal loading of 0.8 % supported on nanostructured support was active and selective for the hydrogenation of sunflower oil under mild process conditions. It produced less saturated acid and reached a good selectivity towards monoenes. In all cases, the consecutive impregnations of Pd and a second metal on the mesoporous silica support preserved the mesoporous structure of the support with slight modification of the textural characteristics in terms of BET surface area, pore size distribution and total pore volume. The addition of nominal 0.2 % Co, Sr or Ru to 0.8% Pd-catalyst enhanced its activity. However, the addition of nominal 0.2 % Ni or Mo dropped the activity of monometallic Pd-catalyst significantly. It is clearly shown that Ru had some promoting effect to inhibit further the formation of trans fatty acids. The addition of a second metal to Pd-catalyst had no significant effect on the formation of C18:0.High degree of metal-metal, metal-support as well as metal-oil interactions would greatly influence the reaction mechanisms of the vegetable oil hydrogenation.
Experimental and Numerical Study of Rotating Fluidized Beds in a Static Geometry
Authors: De Wilde Juray , Habibi Ali , de Broqueville Axel
Published: December 2007

The new concept of a rotating fluidized bed in a static geometry was numerically and experimentally studied. The particle bed can be both tangentially and radially fluidized by injecting the fluidization gas tangentially in the static fluidization chamber via multiple gas inlet slots located in its outer cylindrical wall. The tangential fluidization of the particles induces a rotating motion of the particle bed. As a result of the particle bed rotational motion, the solids experience a radially outwards centrifugal force. A radially inwards gas-solid drag force and radial fluidization of the particle bed can be introduced by forcing the fluidization gas to leave the fluidization chamber via a chimney with one or multiple gas outlet slots, positioned at the axis of the fluidization chamber. The solids can be continuously fed and removed in and out of the fluidization chamber via solids inlet and outlet holes in the front or back ends of the fluidization chamber.The fluidization patterns of low-density polymer particles with a large diameter and of high-density salt particles with a small diameter were experimentally studied in a 24-cm diameter, 13.5-cm long non-optimized static fluidization chamber at different solids loadings. Scale-up to a 36-cm diameter fluidization chamber was also studied. With both types of particles, a rotating fluidized bed and an acceptable gas-solid separation was obtained provided that the solids loading was sufficiently high. Slugging and channeling and a non-uniform distribution of the gas over the gas inlet slots to the fluidization chamber may occur at low solids loadings and can be detected via well-chosen pressure measurements. The fluidization patterns observed in the same fluidization chamber were completely different with the polymer particles and with the salt particles. The polymer particles tend to form a dense and uniform bed, its behavior being mainly characterized by tangential fluidization. The salt particles tend to form a less dense, bubbling fluidized bed that is both tangentially and radially fluidized.Computational fluid dynamics simulations give an improved insight in the gas and solid phase flow pattern.
A Christmas Warning
Authors: Edlin Aaron S.
Published: December 2007

Aaron Edlin points out that Microsoft continues to profit at its users' expense by creating incompatibilities, and suggests that you think twice before asking Santa for a new Windows machine with Vista and Office 2007.
Optimization of Enzyme Assisted Processes for Extracting and Hydrolysing Corn Proteins Aiming Phenylalanine Removal
Authors: Capobiango Michely , Lopes Daniella Cristine Fialho , Carreira Raquel Linhares , Afonso Wendel de Oliveira , Segall Sérgio Duarte , Silvestre Marialice Pinto Coelho
Published: December 2007

Two enzyme assisted processes were studied in this work, protein extraction and hydrolysis, aiming phenylalanine (Phe) removal from corn. For protein extraction, a protease of Bacillus liccheniformis was used and the effect of temperature (55 and 60°C) and time (1, 5, 15 and 24 h) was evaluated. For Phe removal, a pancreatin was used for hydrolyzing corn proteins and the activated carbon (AC) was the adsorbent support. In this case, the influence of several parameters was estimated, such as protein extract concentration, E:S ratio, use of freezedrying, protein: AC ratio and way of using AC. The efficiency of Phe removal was evaluated by second derivative spectrophotometry, measuring the Phe content in the corn flour as well as in the hydrolysates after AC treatment. The results showed that the time and the temperature influenced the protein extraction yield and the best results were obtained at 55°C, after 5 h, 15 h and 24 h of reaction, having reached an average extraction yield of 85.3%. The removal of Phe, changed from 68.63 to 97.55%, and its final concentration from 18.80 to 240.75 mg/100 g hydrolysate. The condition that produced the highest Phe removal was the one using a protein extract concentration = 1%, E:S = 1 or 2%, pH 9, temperature = 25°C, protein: C = 1:88.5, using three types of AC and freezedrying (hydrolysates H1 and H2). However, this condition presents some disadvantages such as the use of freezedrying, which highly raises the process cost, and a non-controlled and non-repeatable reaction. Among the samples with no freezedrying stage and more controllable reaction (H9 and H10), H10 is the best one, since it showed smaller Phe content (149.27 mg/100 g) using three types of AC, which is advantageous from the technical point of view. The reduction of the protein: AC ratio, for these two hydrolysates (H9 and H10) was not beneficial for Phe removal, leading to higher Phe content.
Advanced Computational Techniques for Solving Desalination Plant Models Using Neural and Genetic Based Methods
Authors: Mjalli Farouq S. , Abdel-Jabbar Nabil , Ettouney Hisham , Qiblawey Hazim A.M.
Published: December 2007

Simulation of multi-stage flash (MSF) desalination processes that have a production capacity range between 50,000 to 75,000 m3/d is an intensive computational problem that requires high computer processing speed despite the availability of advanced processing computer power in hand nowadays. In this work, a comparative study is conducted to explore the performance of different numerical techniques to solve large set of nonlinear equations generated by large scale MSF models. These algorithms can be categorized into three groups, namely: conventional numerical approximation methods, multi-objective optimization based methods, and the last group comprises artificial neural networks (ANN) based models and genetic algorithms (GA) based methods. The problem of solving large sets of nonlinear equations with upper and lower constraints is accomplished successfully using all algorithms with different prediction efficiency and speed. The idea of using GA and ANN based algorithms in simulating the MSF model is basically used to generate feasible initial solution estimates that were used as starting guesses for other numerical methods in the former case and to eliminate the step of providing these initial guesses in the later case. Significant reduction of computation effort was attained using ANN-based techniques. The outcome of this work can be utilized to develop new generations of process simulators that are based on well-trained ANNs in order to achieve speedup of computations and to generate more reliable predictions without detracting from accuracy.
Cross-Border Shopping and the Sales Tax: An Examination of Food Purchases in West Virginia
Authors: Tosun Mehmet S , Skidmore Mark L
Published: December 2007

In this article we present new evidence of cross-border shopping in response to sales taxation. While several instructive studies provide estimates of the cross-border shopping effect, we utilize a unique opportunity to evaluate the effect of a large discrete change in sales tax policy. Using county level data on food sales and sales tax rates for West Virginia over the 1988-1991 period we estimate that for every one-percentage point increase in the county relative price ratio due to the sales tax change, per capita food sales decreased by about 1.38 percent. Our estimates indicate that food sales fell in West Virginia border counties by about eight percent as a result of the imposition of the six percent sales tax on food at the beginning of 1990.
A Consistent Multidimensional Generalization of the Pigou-Dalton Transfer Principle: An Analysis
Authors: Diez Henar , Lasso de la Vega M. Casilda , de Sarachu Amaia , Urrutia Ana M.
Published: December 2007

This paper explores the implications of using multidimensional majorization criteria to derive inequality measures, without taking into consideration the idea behind the Pigou-Dalton principle, in the sense that if a richer person transfers something of at least one attribute to a poorer person the inequality falls. A new and basic criterion proposed by Fleurbaey and Trannoy (2003) which generalizes this idea to the multidimensional framework is explored, and its logical relationships with the dominance criteria that exist in the literature are analyzed. The paper also surveys the existent multidimensional inequality indices in order to see whether they meet this new criterion.
Comparative demography of three coexisting Acer species in gaps and under closed canopy
Authors: Tanaka H. , Shibata M. , Masaki T. , Iida S. , Niiyama K. , Abe S. , Kominami Y. , Nakashizuka T.
Published: December 2007

Questions: 1. Is there a trade‐off between gap dependency and shade tolerance in each of the life‐history stages of three closely related, coexisting species, Acer amoenum (Aa), A. mono (Am) and A. rufinerve (Ar)? 2. If not, what differences in life‐history traits contribute to the coexistence of these non‐pioneer species?

Location: Ogawa Forest Reserve, a remnant (98 ha), species‐rich, temperate deciduous forest in central Japan (36°56’ N, 140°35’ E, 600 ‐ 660 m a.s.l.).

Methods: We estimated the demographic parameters (survival, growth rate and fecundity) by stage of each species growing in gaps and under closed canopy through observations of a 6‐ha permanent plot over 12 years. Population dynamics were analysed with stage‐based matrix models including gap dynamics. Results: All of the species showed high seedling and sapling survival rates under closed canopies. However, demographic parameters for each growth stage in gaps and under closed canopies revealed inter‐specific differences and ontogenetic shifts. The trade‐off between survival in the shade and growth in gaps was detected only at the small sapling stage (height < 30 cm), and Ar had the highest growth rate both in the shade and in the gaps at most life stages.

Conclusions: Inter‐specific differences and ontogenetic shifts in light requirements with life‐form differences may contribute to the coexistence of the Acer species in old‐growth forests, with Aa considered a long‐lived sub‐canopy tree, Am a long‐lived canopy tree, and Ar a short‐lived,‘gap‐phase’ sub‐canopy tree.
The diagnostic and prognostic value of tau‐PET in amnestic MCI with different FDG‐PET subtypes
Authors: Boccalini Cecilia , Caminiti Silvia Paola , Chiti Arturo , Frisoni Giovanni B. , Garibotto Valentina , Perani Daniela ,   the Alzheimer's Disease Neuroimaging Initiative
Published: March 2024

Objectives

Mild cognitive impairment presenting with an amnestic syndrome (aMCI) and amyloid positivity is considered due to AD. Many subjects, however, can show an overall very slow progression relevant for differential diagnosis, prognosis, and treatment. This study assessed PET biomarkers, including brain glucose metabolism, tau, and amyloid load, in a series of comparable aMCI at baseline, clinically evaluated at follow‐up.

Methods

We included 72 aMCI subjects from Geneva Memory Center (N = 31) and ADNI cohorts (N = 41), selected based on available FDG‐PET, tau‐PET, amyloid‐PET, and clinical follow‐up (2.3 years ± 1.2). A data‐driven algorithm classified brain metabolic patterns into subtypes that were then compared for clinical and PET biomarker measures and cognitive decline. Voxel‐wise comparisons were performed both with FDG‐PET and tau‐PET data.

Results

The algorithm classified three metabolic subtypes, namely “Hippocampal‐sparing with cortical hypometabolism” (Type1; N = 27), “Hippocampal and cortical hypometabolism” (Type 2; N = 23), and “Medial temporal hypometabolism” (Type 3; N = 22). Amyloid positivity and tau accumulation in the medial temporal and neocortical regions characterized Type 1 and Type 2, whereas Type 3 showed no significant tau pathology, variable amyloid positivity, and stability at follow‐up. All tau‐positive patients, independently of the FDG‐based subtype, showed faster cognitive decline.

Interpretation

aMCI subjects can differ in metabolic patterns, tau and amyloid pathology, and clinical progression. Here, we complemented with PET tau biomarker the specific brain hypometabolic patterns at the individual level in the prodromal phase, contributing to the patient's classification. Tau PET is the most accurate biomarker in supporting or excluding the AD diagnosis in aMCI across metabolic subtypes and also predicting the risk of decline.
Research on image processing of electric power system terminals based on reinforcement learning and mobile edge computing optimization
Authors: Zhou Hui , Yu Jun , Luo Huafeng , Wang Liuwang , Yang Binbin
Published: March 2024

This research is dedicated to the optimization of power system terminal image processing based on RL and MEC. With the continuous development of power system, the demand for image processing of terminal equipment is increasing day by day. However, traditional image processing methods have the problems of high computing complexity and real‐time and energy consumption. To solve this problem, this study introduces the idea of RL and MEC to improve the efficiency and performance of image processing of power system terminals. By modeling and optimizing the image processing task of the power system terminal equipment, the intelligent adjustment of the processing parameters is realized to adapt to the needs of different scenarios. MEC technology is introduced to move image processing tasks from the central server to the edge device, reducing data transmission delay and network burden, thus improving real‐time performance and reducing energy consumption. The experimental results show that the proposed optimization method based on RL and MEC has a significant performance improvement compared with the traditional method in the power system terminal image processing. The framework our proposed has achieved significant improvement in task completion latency, achieving higher system energy efficiency compared to traditional methods.
Effect of Femtosecond‐Laser‐Induced Surface Textures on the Microstructure and Mechanical Properties of Mg/Ti Dissimilar Alloys Laser Lap Welds: A Numerical and Experimental Study
Authors: Zhou Jun , Wang Rongzhu , Long Yu , Li Chen
Published: March 2024

The strength of the joints in the Mg/Ti laser welding is difficult to meet the requirement because of the metallurgical incompatibility. This study investigates the influence of microgroove width on the diffusion of molten Mg and the mechanical properties of joints by laser welding Ti6Al4V and AZ31B, employing femtosecond lasers to fabricate microgrooves on the surface of Ti alloys. The optimal contact angle of 56.4° is achieved at the microgroove width of 100 μm because the leading and trailing edges of the microgroove texture can stimulate the formation of the microriveted structure, facilitating the fluidity of the liquid AZ31B. The joint's tensile–shear capability is increased to 2449.9 N, which is 2.8 times stronger compared to joints without microgroove textures, when using a microgroove width of 100 μm and a laser power of 52%. The numerical simulation of the laser welding process was implemented to analyze the temperature field and the fluid characteristics within the melt pool. In the results, it is shown that the microgroove enhanced the material exchange at the interface and accelerated the interfacial reaction, which stimulates the formation of Ti–Al and Mg–Al intermetallic compounds at the central interface of the joint and enhances the Mg/Ti metallurgical bonding.
Influence of Macroscale Dimension on the Electrocrystallization of Cu Pad and Redistributed Layer in Advanced Packaging
Authors: Liu Jin‐Hao , Wan Yong‐Qiang , Gao Li‐Yin , Cui Xian‐Wei , Liu Zhi‐Quan
Published: March 2024

Copper with equiaxed grains (EG Cu), copper with columnar nanotwinned grains (C‐NT Cu), and copper with mixed equiaxed and columnar grains (MG Cu) are electroplated on pads and redistributed layers (RDLs) with different dimensions. When the diameters of pads increase from 40 to 105 μm, the flatness of pads decreases from 34.5% to 24.0%. The flatness gradually deteriorates from 16.5% to 34.4% with the increase of RDL width from 8 to 20 μm. In contrast, the flatness of C‐NT Cu and MG Cu fluctuates between 1% and 5%, showing a weak correlation on the dimension. In terms of microstructure, the EG Cu and MG Cu has a weak correlation with size change, and the grain orientation shows a randomness. However, the (111) texture component of C‐NT Cu differs greatly with different dimensions, especially in transition layer. The (111) texture component changes from 9.6% to 38.1% for ϕ 40–105 μm pad and from 14.3% to 18.9% for 8–20 μm‐wide RDL. The study reveals the significant size effect on the deposited profile and microstructure of electrodeposited copper materials, which should give insights of the materials design in advanced packaging technology.
Methanol‐Facilitated Surface Reconstruction Catalysts for Near 200% Faradaic Efficiency in a Coupled System
Authors: Xia Qing , Jin Chengkai , Huang Yu Lun , Zhai Yanjie , Han Wenkai , Wu Jie , Xia Chuan , Lin Chun Che , Zhao Xunhua , Zhang Xiao
Published: March 2024

The coupling of the carbon dioxide reduction reaction (CO2RR) and methanol oxidation reaction (MOR) holds great promise for the energy‐efficient production of HCOO−. However, anode catalysts' limited selectivity (<80%) and stability (<15 h) have impeded electron utilization and HCOO− production rates. To overcome it, copper‐copper(I) oxide‐copper(II) oxide nanowires (Cu─CuO─Cu2O NWs) catalysts have been developed, which exhibit exceptional performance in promoting the MOR with a faradic efficiency of nearly 100% at commercially viable current densities, and  long stability over 100 h at 100 mA cm−2. Interestingly, the unique structure of the catalysts, when exposed to methanol, facilitates a transition from Cu/CuO to Cu2O. This phenomenon promotes the MOR while inhibiting the competitive oxygen evolution reaction (OER). By coupling the anodic reaction with cathodic CO2 reduction, the system demonstrates exceptional performance in HCOO− production, achieving an overall faradic efficiency of nearly 200% at 100 mA cm−2 with a low cell voltage of 2.382 V. Techno‐economic analysis indicates that the production costs of HCOOH are ≈US$0.37 and 0.35 kg−1 at 100 and 150 mA cm−2, respectively, significantly lower than those associated with traditional electrochemical methods.
Dual‐Sensing Nanoreporter for Dynamic and High‐Throughput Monitoring of Immune Checkpoint Inhibitor Responses in Tumor‐Derived Organoids
Authors: Nguyen Anh , Ramesh Anujan , Fish Adam , Kulkarni Ashish A.
Published: March 2024

Heterogenous immune responses to checkpoint blockade therapy remain a major challenge to early prediction of treatment efficacy. Current methods of evaluating treatment efficacy in tumors are ineffective in accurately monitoring the disease status after immunotherapy early on. This study reports an immune response monitoring strategy that longitudinally reports on two crucial protease activities involved in T cell‐mediated target cell death, granzyme B (GrzB) and downstream caspase 3 (Casp3), during and after immune checkpoint antibody treatment. Specifically, activatable nanoreporters are engineered to sensitively and selectively capture the activity of GrzB and Casp3 enzymes in tumor cells triggered by cytotoxic T cells in real‐time, providing a direct readout of the tumor response to immune checkpoint inhibitors (ICIs). Furthermore, incorporating 3D tumor‐derived organoids and ex vivo cultures on microfluidic devices with nanoreporters enables high‐throughput screening of various ICIs and their combinations in immunocompetent tumor models. These findings suggest that efficient monitoring of dynamic immunological processes in the tumor microenvironment could help uncover mechanisms associated with ICI response or resistance. It is further anticipated that combining the dual‐sensing nanoreporter with tumor‐derived organoid‐on‐chip technology could lead to an early prediction of treatment outcomes with high fidelity and accelerate the development of optimal treatment in immuno‐oncology.
Unveiling the Glucose Oxidase‐Like and Catalase‐Like Activities of Highly Conjugated 3,4,9,10‐Perylenetetracarboxylic Dianhydride for Boosting Biofuel Cells
Authors: Gu Chengcheng , Zhang Lei , Hou Ting , Zhu Dangqiang , Li Feng , Gai Panpan
Published: March 2024

Carbon‐based nanozymes have received considerable attention due to their superior biosafety, enhanced tolerance to extreme conditions, and ease of chemical modification. However, due to limited material diversity and unconfirmed molecular structure, carbon‐based nanozymes face challenges such as relatively low enzyme activity and unclear catalytic mechanisms. The development of materials with well‐defined structures and controllable properties is crucial for promoting the rapid progress of nanozymes. Herein, 3,4,9,10‐perylenetetracarboxylic dianhydride (PD) exhibits both glucose oxidase (GOx)‐like and catalase (CAT)‐like activities, which may be due to the fact that PD possesses the features of highly conjugated structure and high electron mobility. In addition, it is demonstrated that the enzymatic activity is related to the degree of PD aggregation via the characterization of its morphology and size. Based on the excellent GOx‐like and CAT‐like activities of PD, a self‐cascade catalytic system is constructed for application in biofuel cells (BFCs). It is worth mentioning that such BFC still maintains high stability after working for 30 days. Therefore, this study expands the enzyme‐like systems and discovers that nanomaterials with highly conjugated structures and high electron mobility can mimic enzymes. Additionally, the multi‐enzyme activities are utilized to construct self‐cascade systems, which can effectively improve the performance of BFCs.
Red–Green–Blue Light Emission from Composition Tunable Semiconductor Micro‐Tripods
Authors: Song Xiaohang , Xu Zitong , Gao Bo , Li Xuyang , Lv Qihang , Zhang Rui , Wang Bingjie , Zhang Hulin , Guo Pengfei , Ho Johnny C.
Published: March 2024

Micro/nanoscale lasers that span the entire visible spectrum, especially those in red, green, and blue colors, are not only essential for a variety of optical devices but also have important applications in visible color communication, multi‐color fluorescence sensing, and wavelength division multiplexing. Despite the great efforts made to achieve multi‐color lasing using a variety of approaches, on‐chip white light emission and even red, green, and blue multi‐color lasers still suffer from considerable challenges in micro‐nano structures. Here, CdSxSe1−x, CdS, and ZnS micro‐tripod structures are successfully prepared using chemical vapor deposition approaches. The micro‐photoluminescence (µ‐PL) spectra and PL‐mapping of these micro‐tripods reveal various emissions at 630, 508, and 460 nm, respectively. Additionally, white‐light emissions based on these composition‐tunable tripods are realized through an end‐coupling structure system. Moreover, room‐temperature modes tunable lasers are observed clearly from three legs of these micro‐tripods, with a low threshold of ≈48.39 µJ cm−2 and a high quality factor of 1227.3. The realization of micro‐tripods‐based lasers may provide an innovative way for highly integrated photonic circuits and communications.