bluuebunny/crossref_metadata_2025 huggingface dataset:
Planning for the First Light Rail Transit System in Korea: Jeonju Light Rail Transit Project
Authors: Shin Yong Eun , Vuchic Vukan R. , Sin Pan-Sik , Eun Cheol-Gyu
Published: May 2007

Pursuing a low-cost, yet modern, high-quality, medium-capacity transit system to improve their transit services, several Korean cities have opted for automated guided transit systems. Yet in 1999 the city of Jeonju decided to introduce a light rail transit (LRT) system not only to improve its transit services but also to improve living conditions, expand business activities, and increase livability. The initial study was performed in 1999, and the preliminary engineering study was completed in 2001. The project is now into the final design leading up to construction. The system consists of a network of two independent lines 24.92 km long with 46 stations and is planned to operate mainly on the street median with a separate right-of-way. The project will be financed and operated by the public sector according to the Public Investment Inducement Act. The first line is scheduled to open in 2008 and the second line in 2010. Numerous issues and elements should be considered for successful project implementation because Korea has no experience in building an LRT system. Although the project seems to be going well, opposition from local organizations has been encountered. The history of the Jeonju LRT system is presented. The system features are described, including network alignment, projected ridership, and financing. Major elements considered and issues encountered during the planning process are also discussed.
Market Segmentation Approach to Mode Choice and Ferry Ridership Forecasting
Authors: Outwater Maren L. , Modugula Vamsec , Castleberry Steve , Bhatia Pratyush
Published: May 2007

The San Francisco Bay Area Water Transit Authority is evaluating expanded ferry service, as required by the California legislature. Predicting ferry ridership has historically been difficult because water-transit riders often choose their travel mode based on factors other than travel time and cost. Most forecast models place a premium on time and cost and ignore other traveler attitudes. Structural equation modeling was used to identify simultaneously travel behavior and the causal relationships between a traveler's socioeconomic profile and travel attitudes. These market segments were used to estimate stated-preference (SP) mode choice models for 14 alternative modes, which separated the traveler's reaction to time savings by market segment and recognized that modal choices were different for market segments that were sensitive to travel stress or a desire to help the environment. The focus was on the application of the model to evaluate three future-year alternatives and to test the sensitivity of pricing policies, service changes, and alternative transit modes. These sensitivity runs included increased tolls on bridges, parking charges for Bay Area Rapid Transit stations, reduced ferry headways, alternative transit investments (express buses) in ferry corridors, and combinations of these assumptions. The results from these model runs were used to support the environmental impact statement and implementation and operations plan and were used to prioritize routes for further consideration based on the ridership potential in the corridor. Preliminary work to competitively position a ferry system that maximizes ferry mode share based on the market segments in the corridor was undertaken for a few routes.
Quantitative Risk Assessment Decision-Support Model for Locating Hazardous Materials Teams
Authors: Hamouda Ghada , Saccomanno Frank , Fu Liping
Published: May 2007

A risk-based decision-support model is presented for locating hazardous materials (hazmat) teams on a regional road network. The model attempts to minimize the total networkwide risk, while ensuring that the response times to all demand nodes are within an acceptable limit. The relevance of the model as a decision-support tool is demonstrated through a case application to a regional road network in southwestern Ontario. The case study has demonstrated some useful decision-support features of the proposed model concerning issues such as how many hazmat teams should be allocated in a region and where they should be located.
Preliminary Results of Experimental Economics Application to Urban Goods Modeling Research
Authors: Holguín-Veras José , Thorson Ellen , Ozbay Kaan
Published: May 2007

The setting and the preliminary results are described in regard to an experimental economics application to urban goods modeling research. With a simplified representation of the New York City metropolitan area, a simulation system at the heart of the economic experiment was used to capture the behavior of a set of volunteers playing the role of trucking companies trying to maximize profits in a context of market competition. The resulting data sets represent an approximation of the spatial price equilibrium solutions that provide a wealth of information about the joint behavior of shippers, receivers, and trucking companies in urban areas. These data sets were used to gain insights into the effect of network and market structure on a set of performance measures created for each of the trucking companies in the data. Overall, in the context of spatial price equilibrium behavior, the trucking companies' performance measures depend on factors such as the number of centroids in the overall market, number of competitors for transportation of cargoes, amount of freight to be transported, and level of market transparency.
Methodology for Modeling a Road Network with High Truck Volumes Generated by Vessel Freight Activity from an Intermodal Facility
Authors: Klodzinski Jack , Al-Deek Haitham M.
Published: May 2007

An innovative methodology has been developed for analyzing freight movement on local road networks by merging previously developed truck trip generation models using artificial neural networks (ANNs) and a microscopic network simulation model. Through computer simulation, this methodology comprehensively analyzes a seaport considered a special generator of heavy truck traffic and an adjacent road network that includes identified intermodal routes that connect to a seaport. Truck traffic from the seaport is initially modeled with ANNs using vessel freight activity at the seaport. These ANN models have been incorporated into the methodology to provide accurate truck and total traffic volumes for modeling the networks. This methodology was successfully tested with two network microscopic simulation models. Transferability was successfully tested with two seaports with different characteristics. Three months of field data from each port and selected locations on the networks were used in calibration and validation. Both models were successfully validated and showed no statistically significant difference between the field and model output data. This methodology can be used to evaluate local port networks to manage traffic efficiently during heavy congestion or investigate forecasted port growth. These networks can also be used for information technology applications such as incident management or alternative route choice. The ability to develop a network that includes significant truck volumes generated by freight activity is a useful tool especially for engineers and planners involved in intermodal transportation analysis.
Short-Haul Rail Intermodal: Can It Compete with Trucks?
Authors: Resor Randolph R. , Blaze James R. , Morlok Edward K.
Published: May 2007

Intermodal traffic, that is, truck trailers or ocean containers handled on special rail equipment, is the fastest-growing segment of rail traffic. Between 1990 and 2000, rail intermodal grew at an annual rate of 4.6%—much faster than rail carload freight, which grew at an annual rate of only 1.4%. However, during the same period, truck tonnage grew at an annual rate of 6.9%, and air cargo at a rate of 17.9%. The growing rail intermodal is expected to overtake coal as the single largest source of revenue for freight railroads in the year 2004. But railroad intermodal tonnage is not growing as fast as truck traffic, and market share is consequently falling. This is a problem: with total freight traffic projected to grow 57% by the year 2020, all the increased traffic will have to be accommodated on the highway network. The introduction of double-stack rail cars in the 1980s dramatically reduced rail haul costs, and it made intermodal traffic competitive at distances of 500 mi or so, whereas previously rail could compete with trucks only at distances of about 750 mi or more. Still, most rail intermodal traffic remains long haul. Three-quarters of all truck tonnage moves distances of less than 500 mi, and rail does not compete in this market. Rail haul costs are developed for a number of short corridors, and it is demonstrated that although double-stack usage has lowered line haul costs, terminal and drayage costs remain high. If these costs can be reduced, rail intermodal can be competitive even in short-distance corridors. Several ways to lower these costs, both by industry initiatives and by public investment, are proposed. Without some action by the public sector, short-haul rail intermodal will continue to be noncompetitive, and highway truck traffic will continue to grow.
Formulas for Estimating Average Distance Traveled in Vehicle Routing Problems in Elliptic Zones
Authors: Robusté F. , Estrada M. , López-Pita A.
Published: May 2007

Some compact expressions are defined to evaluate the average distance traveled in vehicle routing problems in circular and elliptic zones. These formulas have been carried out empirically from the results obtained by the application to a set of problems of heuristic algorithms (Clarke and Wright, Fisher and Jaikumar, and Gillet and Miller) and Daganzo's method based on continuous approximations of the demand spatial distribution. The problems are solved and designed automatically by a computer. Vehicle capacity has been the only constraint considered in the tour design. If N is the number of points and C is the vehicle capacity, it has been shown that the Clarke and Wright algorithm provides the best solutions especially when N < 50 or N/C < 14. However, solutions with Daganzo's method are not adequate when N/C ≤ 3.
Introducing Level-of-Service Standards for Intermodal Freight Terminals
Authors: Ballis Athanasios
Published: May 2007

The quality of service issue plays a key role in the design and operation of intermodal freight terminals. Though not straightforwardly stated, the level of service offered by these facilities is strongly related to the terminal's productivity as well as to the decisions associated with infrastructure investment. Despite its importance, no widely accepted set of service standards has yet been adopted. On the basis of a number of considerations and the findings of relevant research projects, such a set of standards is introduced to provide reference values for investment strategies and terminal design studies and research. This set of standards is also useful for the interpretation of directives at the policy level and to quantified guidelines at the planning level.
Advanced Rail and Maritime System Demonstrations in Europe
Authors: Ballis Athanasios , Morlok Edward K.
Published: May 2007

The development of innovative systems for rail and maritime terminals is an issue high on the agenda of the transport industry. In Europe, a number of new transport systems for unitized cargoes are already in the mature design or pilot phase. A study was done to present a subset of these systems for which pilot demonstrations exist, to identify the basic directions of the relevant technological research and to evaluate the effects of these systems on the structural and operational environment of the terminals. The relevant analysis was based on the experience extracted by field trials as well as by modeling tasks used for the evaluation of the related terminal performance. It was revealed that tasks such as the reduction of terminal access time, fast train loading and unloading, and achievement of high degrees in equipment automation are technically and operationally feasible.
Hard Aggregate Resistance to Studded Tires: Alaskan Experience
Authors: Frith Douglas J. , Morian Dennis A. , Stoffels Shelley M. , Saboundjian Steve
Published: May 2007

The results and methodology used to evaluate the cost-effectiveness of using harder aggregate in Alaska in an effort to reduce the wear caused by studded tires are presented. Scandinavian countries have studied the relationship between aggregate hardness, as measured by the Nordic abrasion value, and studded tire wear and have shown that harder aggregates have resulted in improved pavement performance. High-quality aggregates are not readily available throughout Alaska; therefore, a cost-effectiveness study of improved aggregate hardness was needed. Performance models based on the existing wear rates within the Anchorage, Fairbanks, and Juneau regions were developed. On the basis of existing performance data, studded tire wear is not a problem in the Fairbanks region, although this cannot be explained by aggregate hardness. Areas of greatest concern are the Anchorage and Juneau regions. Performance models relating pavement wear to the Nordic abrasion value of aggregates were developed. A methodology for evaluating the cost-effectiveness of transporting improved aggregates is provided. On the basis of the cost and performance data gathered, pavement wear caused by studded tires can be reduced and result in improved performance of the pavement in a cost-effective manner. Through the use of harder aggregates conforming to the Nordic abrasion specification, pavement performance can be increased by 1.4 to 1.9 times that currently experienced in the Anchorage and Juneau regions, respectively.
Harmonized Resilient Modulus Test Method for Unbound Pavement Materials
Authors: Andrei Dragos , Witczak Matthew W. , Schwartz Charles W. , Uzan Jacob
Published: May 2007

A new laboratory test protocol for the measurement of resilient modulus of unbound pavement materials is described. This harmonized protocol combines the best features from four state-of-the-art resilient modulus test procedures in current use. The harmonized procedure most closely follows the recommended protocol proposed in NCHRP Project 1-28, Appendix E, with some exceptions. The main modifications deal with revised and more rational stress sequences and a more accurate stress-dependent resilient modulus predictive equation. Thirteen different predictive models and 25 sets of resilient modulus test data were evaluated as the basis for the recommended predictive equation.
Predicting Elastic Response Characteristics of Unbound Materials and Soils
Authors: Yau Amber , Von Quintus Harold L.
Published: May 2007

Most state transportation agencies in the United States use the 1986 or 1993 version of the AASHTO design guide. The AASHTO guide for the design of flexible pavements uses the resilient (elastic) modulus as the property for characterizing all pavement materials and soils. However, state agencies do not routinely measure the resilient modulus in the laboratory but instead estimate the value from strength tests or physical properties. Physical property and repeated load resilient modulus tests are being performed on all unbound materials and soils within the Long-Term Pavement Performance (LTPP) program. Other correlation studies have been performed relating physical properties to the k coefficients of the resilient modulus constitutive equation but have been confined to specific soils. The LTPP program includes a diverse range of soils and unbound pavement materials for which the physical properties and resilient modulus are being measured. Thus, statistical analyses were initiated to confirm these relationships and define the accuracy of predicting the elastic response parameters for use in design. Results from these analyses suggest that the correspondence between the physical properties and the elastic parameters of the resilient modulus constitutive equation was fair to poor. It was also found that sampling technique had an effect on the elastic parameters of some unbound materials and soils. On the basis of the findings, it was recommended that resilient modulus tests be performed to characterize unbound materials and soils accurately for use in design.
Performance of Prototype Embankment Built with Tire Shreds and Nongranular Soil
Authors: Zornberg Jorge G. , Costa Yuri D. , Vollenweider Brent
Published: May 2007

The mechanical response of a prototype embankment fill built with tire shreds and nongranular soil was evaluated. The test embankment consisted of three distinct sections, each 10 m (33 ft) long and 1.5 m (4.9 ft) high. Specifically, the embankment included a layered section composed of successive layers of soil and tire shreds, a soil-tire shred mixed section with 10% tire shreds by weight, and a pure soil section. The embankment was exposed to heavy-truck traffic immediately after construction. At 120 days after construction, the settlement rate in the two sections containing tire shreds converged to a rate similar to that observed in the section of pure soil. However, the section constructed with soil-tire shred mixture exhibited a better overall long-term behavior than the layered section, as it showed smaller differential settlements. The results collected in this study also provide insight into the in situ compression and compaction procedures and preparation characteristics of soil-tire shred mixtures and soil-tire shred layered systems.
Use of Recycled and Waste Materials in Indiana
Authors: Siddiki Nayyar Zia , Kim Daehyeon , Salgado Rodrigo
Published: May 2007

The improved generation, handling, and safe disposal of waste and recycled materials have become a major concern in the United States. Generators of waste are under growing pressure either to find new facilities to dispose of it, as old facilities reach their capacity, or to recycle the waste. In addition to a scarcity of disposal facilities and the associated escalating costs, stringent regulations and public perceptions have caused local governments to seek ways to use waste materials in a productive way. The Indiana Department of Transportation has been proactive and has initiated and funded several research projects in cooperation with generators to determine safe and beneficial uses in road construction. Efforts are still under way to find economically feasible and environmentally sound geotechnical applications of waste and recycled materials. This study consolidates results of research on geotechnical applications of coal combustion by-products, foundry sand, tire shreds, and crushed glass. Project case histories and revised construction specifications based on postconstruction evaluations are also presented. These geotechnical applications suggest that significant cost savings can be attained, in addition to the positive environmental impact, with the use of these materials.
Correlation Between Resilient Modulus, Moisture Variation, and Soil Suction for Subgrade Soils
Authors: Khoury Naji N. , Zaman Musharraf M.
Published: May 2007

In recent years, interest in determining the influence of moisture changes on the resilient modulus ( MR) of subgrade soils beneath a pavement has increased. This is because the 1993 AASHTO Guide for Design of Pavement Structures recommends using a single MR value. The design MR is expected to account for the seasonal variation in subgrade moisture content. This study was undertaken to evaluate the variation of MR with postcompaction moisture content and suction of selected subgrade soils in Oklahoma. A sandy soil (S-Soil) and a clayey soil (C-Soil) were used for laboratory testing. The C-Soil specimens to be subjected to wetting were prepared by a modified compaction method. The proposed method was expected to enhance the flow of water in a specimen during the wetting process. New laboratory procedures for wetting and drying of specimens were also introduced and were used to establish correlations among MR, moisture variation, and suction. Results indicate that MR-moisture content relationships for C-Soil exhibit a hysteretic behavior due to wetting and drying. A similar behavior was observed for S-Soil. The C-Soil was more susceptible than the S-Soil to moisture variation, as expected. It was also observed that changes in MR values and suction were influenced by the initial (compaction) moisture content.
Modulus Anisotropy and Shear Stability of Geofiber-Stabilized Sands
Authors: Tutumluer Erol , Kim In Tai , Santoni Rosa L.
Published: May 2007

A systematic laboratory approach is established to evaluate shear stability or bearing capacity improvement of sand-geofiber stabilization for rapid road and airfield construction. The approach deals with the investigation of directional dependency, anisotropy, and modulus properties and links stability to shear stress levels typically applied on specimens during testing in relation to their strength. An advanced triaxial testing machine referred to as the University of Illinois FastCell is used together with direct shear tests for determining the anisotropic resilient moduli and the strength properties of two geofiber-reinforced sands (poorly and uniformly graded sands) prepared with three 51-mm geofibers: fibrillated, monofilament, and tape. The use of different geofiber types and the various amounts of clay and silt fines present in the sand mixtures significantly affected the recorded horizontal and vertical moduli and the shear stresses at applied stress states. Monofilament-type geofiber stabilization was found to be the most effective, with the recorded highest vertical moduli and the highest shear strength and stability improvement indicated by the lowest shear stress ratios, especially when mixed with 10% to 20% clay. The tape-type geofiber reinforcement generally was not very effective. For the geofiber stabilization of sands to be a viable construction alternative, the sand-geofiber mixtures should contain an optimal amount of fines needed for geofibers to mobilize the shear strength of the mix effectively and thereby improve the shear stability and resistance to permanent deformation.
Slope Rehabilitation at the Baltimore-Washington Parkway with Rammed Aggregate Piers
Authors: O'Malley Edward S. , Saunders Scott A. , Ecker John J.
Published: May 2007

The Baltimore-Washington Parkway is a major traffic artery traveled by daily commuters in suburban Washington, D.C. Much of the parkway roadbed lies on a raised embankment constructed to allow for grade separation between the parkway and surface streets, facilitating access to the parkway. After a series of rainstorms in the fall of 2002, the fill embankment at the recently reconstructed Route 197 interchange failed, with resulting settlement and lateral movement of a retaining wall that supported the southbound lanes of the parkway. The slide encroached on the traffic lanes and jeopardized the integrity and safety of the parkway. After analyzing a variety of possible solutions, FHWA and the National Park Service opted to stabilize the slide by using Geopier rammed aggregate piers, acting in concert with a toe berm stabilized with Tensar highstrength structural geogrid. The rammed aggregate piers improved the stability of the slope by providing significant increases in the composite shear resistance because of their high angle of internal friction (44° to 52°). A case history is presented of the use of rammed aggregate piers to stabilize a landslide. The analytical methods used in the design solution are presented along with a description of the construction sequence. This study is significant because it describes how a simple and cost-effective solution may be implemented to stabilize landslides.
Measurement of In Situ Hydraulic Conductivity and Coefficient of Consolidation with Prefabricated Vertical Drains
Authors: Welker Andrea L. , Devine Brian J. , Goughnour R. Robert , Foster Jimmy
Published: May 2007

Prefabricated vertical drains (PVDs) are often used to improve soils by speeding up the rate of consolidation, and they are increasingly used for remediation of contaminated soils. When PVDs are installed in the ground, there is always a zone of disturbed soil surrounding them. The extent and the impact of this "smear" zone are difficult to quantify, and this uncertainty complicates the use of laboratory values in design. Consequently, obtaining in situ values for the hydraulic conductivity and horizontal coefficient of consolidation that include the effects of smear would be of great use to engineers who use PVDs in design. A method that utilizes PVDs to obtain in situ measurements of these parameters is described. The primary advantages of this method are its cost-effectiveness and the inclusion of smear in the results. A trial test was conducted on San Francisco Bay, California, mud. Some problems encountered during the initial phase of testing are described, and possible solutions are discussed. This promising method yields values that are logical and that compare well with published values for San Francisco Bay mud.
Field Validation Study of Low-Temperature Performance Grading Tests for Asphalt Binders
Authors: Iliuta Serban , Hesp Simon A. M. , Marasteanu Mihai O. , Masliwec Tony , Tam Kai K.
Published: May 2007

Current performance-graded asphalt cement specification testing to predict low-temperature performance was examined for effectiveness and deficiencies. The ability of various binder properties to predict cracking in the field was assessed for 17 trial sections constructed in northern Ontario. The tests included the currently used bending beam rheometer and direct tension tests, as well as a more fundamental fracture mechanics-based method. The results indicated that the currently used grading procedure predicted the ranking for most sections within each site reasonably well but was poor at predicting the onset of cracking. The need for improvement was illustrated with two sections on Provincial Highway 631, which were constructed in 1991 with binders of the same grade but which showed a difference in transverse cracking severity of nearly a factor 20. Furthermore, two sections on Provincial Highway 118, constructed in 1994 with binders of almost identical grade, were cracked by a more modest difference of 40%. Finally, the PG 58-28 and both of the PG 58-34 sections, which were constructed in 1996 on TransCanada Highway 17—and were exposed to minimum surface temperatures of -26.8°C in their first winter and -27.2°C in 2003 and hence should not have cracked—were damaged by a significant 169, 52, and 65 transverse cracks/km, respectively. Physical aging and notch sensitivity of the binders were indicated as major contributing factors for this early distress.
New Criterion for Superpave High-Temperature Binder Specification
Authors: Dongré Raj , D'Angelo John , Reinke Gerry , Shenoy Aroon
Published: May 2007

The results of a study conducted to determine a new binder parameter that might replace the existing Superpave® high-temperature specification parameter ( G*/sin δ) are described. The current parameter ( G*/sin δ) is inadequate because of increasing concerns about its applicability to polymer and other modified asphalt binders. In this study, several parameters were calculated from rheological test data generated on four asphalt binders of different grades at four test temperatures. Two of the binders were unmodified binders, and the other two were modified binders. Laboratory hot-mix rutting tests also were conducted at three temperatures on the asphalt pavement analyzer (APA) and the dry Hamburg rut testers. APA overestimated the rutting potential of modified binders used in this study. Dry Hamburg produced reasonable results. From the correlation between the dry Hamburg data and binder parameters, the storage viscosity, η', was found to be the most promising binder parameter that could adequately characterize the rutting resistance of both unmodified and modified asphalt binders. Of all of the parameters, it was the easiest to measure with minimal change in existing instrumentation and software. A specification criterion for η' was determined. According to the new criterion, the temperature at which the η' has a value of 220 Pa-s for rolling thin film oven-aged asphalt binders is the high-performance grade (PG grade) temperature that may reasonably replace the current Superpave high-PG grade temperature obtained using G*/sinδ.
Initial Validation of a New Surface Performance-Graded Binder Specification
Authors: Walubita Lubinda F. , Martin Amy Epps , Hazlett Darren , Barcena Roberto
Published: May 2007

Surface treatment design and material selection currently are based on traditional specifications and experience, which are not performance based and sometimes result in inadequate performance of the surface treatment. In 2000, the first phase of a Texas Department of Transportation research study developed a surface performance-graded (SPG) specification for the selection of surface treatment binders. The SPG specification is performance based and uses binder properties directly related to surface treatment performance and associated distresses. The specification takes into account environmental conditions, aging effects of the binder, viscoelastic behavior, and reliability. The objective of the second phase of the study was to ( a) investigate and establish the validity and applicability of the proposed SPG specification by comparing laboratory-measured SPG binder grades to actual observed field performance and making modifications where necessary and ( b) recommend the SPG specification for practical implementation. The research methodology involved highway section identification, including project data collection, laboratory testing including binder SPG grading, field performance monitoring, and data analysis. Factors included in the experimental design were binder type and suppliers, environment, aggregates, and traffic. Analyses of the results showed that there was generally a good correlation between the proposed SPG specification and actual field performance. Overall, the results indicate that the proposed SPG specification is functional; if properly applied, it promises to be a relatively cost-effective method for selecting binders to ensure adequate surface treatment performance.
Using Global Positioning System Data to Understand Day-to-Day Dynamics of Morning Commute Behavior
Authors: Li Hainan , Guensler Randall , Ogle Jennifer , Wang Jun
Published: May 2007

The day-to-day variability of journey-to-work trips, including departure time, route choice, and trip-chaining behavior, was examined with Global Positioning System-based disaggregate morning commute data for 56 drivers during a 1-week period. Data were collected from the ongoing instrumented vehicle projects in Atlanta sponsored by NHTSA and FHWA. The study examines alternative measurements of the day-to-day variability of the commute pattern. While commuting trips are often thought to be highly repetitious and therefore highly predictable trips, research results indicate that commuters change departure times more frequently than routes, and trip chaining significantly affects commuters' departure time and route choice behavior. This study begins to explore definitions and relationships that will be necessary to better understand the day-to-day commute dynamics.
Role of diffusion processes in a model reaction of reesterification
Authors: Naphadzokova L. K. , Kozlov G. V. , Zaikov G. E.
Published: May 2007

A model of diffusion processes for chemical reactions is shown to describe well the main characteristics of a model reaction of reesterification. The structure of the reaction product (a heptylbenzoate molecule) and the formation of its parts are the main factors controlling the diffusion processes in this case. The processes are described within the framework of strange (anomalous) diffusion. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Metal ion interaction of water‐soluble copolymers containing carboxylic acid groups in aqueous phase by membrane filtration technique
Authors: Pizarro Guadalupe Del C. , Marambio Oscar G. , Jeria‐Orell Manuel , Huerta Margarita R. , Rodríguez Oscar O. , Rivas Bernabé L. , Geckeler Kurt E.
Published: May 2007

This article reports the synthesis of poly(N‐maleoylglycine‐co‐itaconic acid) by radical copolymerization under different feed mole ratios and its properties to remove various metal ions, such as Cu(II), Cr(III), Co(II), Zn(II), Ni(II), Pb(II), Cd(II), and Fe(III), in aqueous phase with the liquid‐phase polymer‐based retention(LPR) technique. The interactions of inorganic ions with the hydrophilic water‐soluble polymer were determined as a function of pH and filtration factor. Metal ion retention was found to strongly depend on the pH. Metal ion retention increased as pH and MG content units in the macromolecular backbone increased. The copolymers were characterized by elemental analysis, FTIR, 1H‐NMR, and 13C‐NMR spectroscopy. Additionally, intrinsic viscosity, molecular weight, and polydispersity have been determined for the copolymers. Copolymer and polymer–metal complex thermal behavior was studied using differential scanning calorimetry (DSC) and thermogravimetry (TG) techniques under nitrogen atmosphere. The thermal decomposition temperatures (TDT) were influenced by the copolymer composition. The copolymers present lower TDT than the polymer–metal complex with the same copolymer composition. All copolymers present a single Tg, indicating the formation of random copolymers. A slight deviation of the Tg for the copolymers and its complexes can be observed. The copolymer Tg is higher than the Tg value for the polymer–metal complexes. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Preparation of calcium carbonate/poly(methyl methacrylate) composite microspheres by soapless emulsion polymerization
Authors: Ma Xiaokun , Zhou Bing , Sheng Ye , Wang Chengyu , Pan Yan , Ma Shanshan , Gao Ye , Wang Zichen
Published: May 2007

Calcium carbonate (CaCO3)/poly(methyl methacrylate) (PMMA) composite microspheres were synthesized in a soapless emulsion polymerization process. CaCO3 nanoparticles were pretreated with oleic acid to improve the compatibility between CaCO3 and the monomer methyl methacrylate, and this effectively enhanced the mass fraction of CaCO3 in the composite. The results of the thermogravimetric analysis showed that the thermal stability of the composite microspheres was better than that of PMMA. X‐ray diffraction and Fourier transform infrared were applied to investigate the chemical and physical properties of the composite microspheres, and the results proved that the composites were composed of CaCO3 and PMMA. Scanning electron microscopy and transmission electron microscopy pictures showed that the morphology of the composite microspheres was uniform, and the CaCO3 nanoparticles could be well dispersed in the polymeric matrix. The soapless emulsion polymerization process effectively increased the filling amount of CaCO3 in the composite microspheres. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Evolution of direct‐developing larvae: selection vs loss
Authors: Smith Margaret Snoke , Zigler Kirk S. , Raff Rudolf A.
Published: May 2007

Observations of a sea urchin larvae show that most species adopt one of two life history strategies. One strategy is to make numerous small eggs, which develop into a larva with a required feeding period in the water column before metamorphosis. In contrast, the second strategy is to make fewer large eggs with a larva that does not feed, which reduces the time to metamorphosis and thus the time spent in the water column. The larvae associated with each strategy have distinct morphologies and developmental processes that reflect their feeding requirements, so that those that feed exhibit indirect development with a complex larva, and those that do not feed form a morphologically simplified larva and exhibit direct development. Phylogenetic studies show that, in sea urchins, a feeding larva, the pluteus, is the ancestral form and the morphologically simplified direct‐developing larva is derived. The current hypothesis for evolution of the direct‐developing larval form in sea urchins suggests that major developmental changes occur by neutral loss of larval features after the crucial transition to a nonfeeding life history strategy. We present evidence from Clypeaster rosaceus, a sea urchin with a life history intermediate to the two strategies, which indicates that major developmental changes for accelerated development have been selected for in a larva that can still feed and maintains an outward, pluteus morphology. We suggest that transformation of larval form has resulted from strong selection on early initiation and acceleration of adult development. BioEssays 29:566–571, 2007. © 2007 Wiley Periodicals, Inc.
On the Magic Character of Al6Au‐.
Authors: Kimble Michele L. , Castleman Albert W. Jr. , Reveles Jose U. , Khanna Shiv N.
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Crystal Structure of the TmAgTe2 Compound.
Authors: Gulay L. D. , Stepien‐Damm J. , Daszkiewicz M. , Pietraszko A.
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
New Three‐Dimensional (3,4)‐Net Zincophosphites Templated by Linear Diammonium Cations: H3N (CH2)5NH3×Zn3 (HPO3)4 and β‐H3N (CH2)6NH3×Zn3 (HPO3)4.
Authors: Holtby Andrew S. , Harrison William T. A. , Yilmaz Veysel T. , Bueyuekguengoer Orhan
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Enantioselective Intramolecular C—H Amidation of Sulfamate Esters Catalyzed by Chiral Dirhodium(II) Carboxylates.
Authors: Yamawaki Minoru , Kitagaki Shinji , Anada Masahiro , Hashimoto Shunichi
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
The Reaction of Fluorine‐Containing Compounds with Conjugated Dienoic Acids Initiated by Sodium Dithionite.
Authors: Mao Shengjie , Fang Xiang , Ba Lu , Wu Fanhong
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Heptadecafluorooctanesulfonic Acid (C8F17SO3H) Catalyzed Intramolecular Hydroamination of Olefinic Sulfonamides in Fluorous Biphase System (FBS).
Authors: Yin Yan , Zhao Gang
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Rhenium(VII) Oxide Catalyzed Heteroacylative Ring‐Opening Dimerization of Tetrahydrofuran.
Authors: Lo H. Christine , Han Hongna , D'Souza Lawrence J. , Sinha Subhash C. , Keinan Ehud
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Na4H3 [SiW9Al3(H2O)3O37] ×12H2O/H2O: A New System for Selective Oxidation of Alcohols with H2O2 as Oxidant.
Authors: Wang Jianmin , Yan Liang , Qian Guang , Li Shunqing , Yang Keli , Liu Haitao , Wang Xiaolai
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
A New Cuburbit[8]uril‐Based Fluorescent Receptor for Indole Derivatives
Authors: Ling Yonghua , Wang Wei , Kaifer Angel E.
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Macrocyclic Ferrocenyl‐Bisimidazoline Palladacycle Dimers as Highly Active and Enantioselective Catalysts for the Aza‐Claisen Rearrangement of (Z)‐Configured N‐para‐Methoxyphenyl Trifluoroacetimidates.
Authors: Jautze Sascha , Seiler Paul , Peters Rene
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Direct Catalytic Asymmetric Synthesis of anti‐1,2‐Amino Alcohols and syn‐1,2‐Diols through Organocatalytic anti‐Mannich and syn‐Aldol Reactions.
Authors: Ramasastry S. S. V. , Zhang Haile , Tanaka Fujie , Barbas Carlos F. III
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Eco‐Friendly Synthesis of Imines by Ultrasound Irradiation.
Authors: Guzen Karla P. , Guarezemini Alexandre S. , Orfao Aline T. G. , Cella Rodrigo , Pereira Claudio M. P. , Stefani Helio A. Stefani Helio A.
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Studies with Azoles and Benzoazoles: A Novel Simple Approach for Synthesis of 3‐Functionally Substituted 3‐Acylindoles.
Authors: Abdel‐Motaleb Ramadan Maawad , Makhloof Abdel‐Moneim Abdel‐Salam , Ibrahim Hamada Mohamed , Elnagdi Mohamed Hilmy
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Ester Derivatives from Tannase‐Treated Prunioside A and Their Antiinflammatory Activities.
Authors: Jun Chang‐Soo , Yoo Myung‐Ja , Lee Woo‐Yiel , Kwak Kyung‐Chell , Bae Moon‐Sung , Hwang Woo‐Taek , Son Dong‐Hwan , Chai Kyu‐Yun
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Oxidative Cyclization of Isodityrosine Tripeptides: Optimized Condition and Application of Electrochemically Generated Thallium(III) Ion.
Authors: Tanabe Takamasa , Obata Rika , Nishiyama Shigeru
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
From Polyoxometalates to Polyoxoperoxometalates and Back Again; Potential Applications
Authors: Bregeault Jean‐Marie , Vennat Maxence , Salles Laurent , Piquemal Jean‐Yves , Mahha Yahdih , Briot Emmanuel , Bakala Paul Celestin , Atlamsani Ahmed , Thouvenot Rene
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Transition‐Metal Complexes with Nanosized Phosphine and Pyridine Ligands — Catalysis, Fluxional Behavior and Molecular Recognition
Authors: Obora Yasushi , Tokunaga Makoto , Tsuji Yasushi
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Molecularly Imprinted Materials: Synthesis, Properties, Applications
Authors: Lisichkin G. V. , Krutyakov Yu A.
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Application of Metal—Carbon Catalysts in Conversions of Lower Aliphatic Alcohols
Authors: Ryashentseva M. A. , Egorova E. V. , Trusov A. I. , Nougmanov E. R. , Antonyuk S. N.
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Catalytic Asymmetric Henry Reaction
Authors: Boruwa Joshodeep , Gogoi Naminita , Saikia Partha Pratim , Barua Nabin C.
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Stereoselective Synthesis of γ‐Amino Acids
Authors: Ordonez Mario , Cativiela Carlos
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Facile synthetic route to enantiopure unsymmetric cis‐2,5‐disubstituted pyrrolidines
Authors: Wang Ping‐An , Xu Zheng‐Shuang , Chen Chun‐Feng , Gao Xu‐Guang , Sun Xiao‐Li , Zhang Sheng‐Yong
Published: May 2007

The (+/−)‐cis‐5‐arylcarbamoyl‐2‐ethoxycarbonylpyrrolidines 6a–g were firstly synthesized in 53–64% yields by using meso‐diethyl‐2,5‐dibromoadipate 3 and (S)‐(−)‐1‐phenylethylamine in three steps. The diastereomeric mixture (S;2S,5R)‐(−)‐7 and (S;2R,5S)‐(+)‐8 were prepared by the Grignard reaction and separated by a flash column chromatography in 29 and 52% yields. The absolute configurations of (+)‐8 was confirmed by X‐ray crystallographic analysis and the enantiopure pyrrolidines (2S,5R)‐(−)‐9/(2R,5S)‐(+)‐9 and (2S,5R)‐(−)‐10/(2R,5S)‐(+)‐10 were obtained in good yields. Chirality, 2007. © 2007 Wiley‐Liss, Inc.
Magnesium und Kohlenstoffdioxid‐(k)eine einfache Reaktion?
Authors: Möllering Jens , Flint Alfred
Published: May 2007

DIE REDOX‐REAKTION zwischen Kohlenstoffdioxid und Magnesium gehört zu den Standardversuchen im Chemieunterricht der Sek. I, wenn es um Redox‐Reaktionen oder die Einordnung von Kohlenstoff in die Redox‐Reihe geht. Eine quantitative Durchführung dieser Umsetzung führt aber ‐ entgegen der verbreiteten Darstellung in Schul‐ und Experimentierbüchern ‐ zu überraschenden Ergebnissen. Tatsächlich reagieren nur etwa 50 % des Magnesiums und des Kohlenstoffdioxids zu Magnesiumoxid und Kohlenstoff. Etwa 25 % der Ausgangsstoffe reagieren zu Kohlenstoffmonooxid und Magnesiumoxid und der Rest zu Magnesiumcarbiden MgC2 und Mg2C3. Diese Magnesiumcarbide können sowohl durch Sekundärreaktion von gebildetem Kohlenstoff mit noch unverbrauchtem Magnesium oder durch direkte Reaktion des Magnesiums mit Kohlenstoffdioxid entstehen. Der in der Regel als Magnesiumoxid bezeichnete graue bis schwarze Belag auf länger lagerndem Magnesiumband ist in Wirklichkeit Magnesiumcarbid MgC2.
Evolutionary conservation and divergence of the segmentation process in arthropods
Authors: Damen Wim G. M.
Published: May 2007

Segments in an embryo of the spider Cupiennius salei. The engrailed gene is expressed in segmentally iterated stripes (dark blue staining) and demarcates the parasegment boundaries. Parasegments are the initial segmental units in all arthropods and are an evolutionary conserved entity in arthropod embryogenesis. The limb primordia that are visible are the ones of the opisthosomal segments 4 and 5, and will form the spinnerets. The bright blue are the cell nuclei stained with DAPI. See Damen et al., Developmental Dynamics 236:1379–1391. © 2007 Wiley‐Liss, Inc.