bluuebunny/crossref_metadata_2025_split huggingface dataset:
Archean to Recent aeolian sand systems and their sedimentary record: Current understanding and future prospects
Authors: Rodríguez‐López Juan Pedro , Clemmensen Lars B. , Lancaster Nick , Mountney Nigel P. , Veiga Gonzalo D. 
Published: April 2014

AbstractThe sedimentary record of aeolian sand systems extends from the Archean to the Quaternary, yet current understanding of aeolian sedimentary processes and product remains limited. Most preserved aeolian successions represent inland sand‐sea or dunefield (erg) deposits, whereas coastal systems are primarily known from the Cenozoic. The complexity of aeolian sedimentary processes and facies variability are under‐represented and excessively simplified in current facies models, which are not sufficiently refined to reliably account for the complexity inherent in bedform morphology and migratory behaviour, and therefore cannot be used to consistently account for and predict the nature of the preserved sedimentary record in terms of formative processes. Archean and Neoproterozoic aeolian successions remain poorly constrained. Palaeozoic ergs developed and accumulated in relation to the palaeogeographical location of land masses and desert belts. During the Triassic, widespread desert conditions prevailed across much of Europe. During the Jurassic, extensive ergs developed in North America and gave rise to anomalously thick aeolian successions. Cretaceous aeolian successions are widespread in South America, Africa, Asia, and locally in Europe (Spain) and the USA. Several Eocene to Pliocene successions represent the direct precursors to the present‐day systems. Quaternary systems include major sand seas (ergs) in low‐lattitude and mid‐latitude arid regions, Pleistocene carbonate and Holocene–Modern siliciclastic coastal systems. The sedimentary record of most modern aeolian systems remains largely unknown. The majority of palaeoenvironmental reconstructions of aeolian systems envisage transverse dunes, whereas successions representing linear and star dunes remain under‐recognized. Research questions that remain to be answered include: (i) what factors control the preservation potential of different types of aeolian bedforms and what are the characteristics of the deposits of different bedform types that can be used for effective reconstruction of original bedform morphology; (ii) what specific set of controlling conditions allow for sustained bedform climb versus episodic sequence accumulation and preservation; (iii) can sophisticated four‐dimensional models be developed for complex patterns of spatial and temporal transition between different mechanisms of accumulation and preservation; and (iv) is it reasonable to assume that the deposits of preserved aeolian successions necessarily represent an unbiased record of the conditions that prevailed during episodes of Earth history when large‐scale aeolian systems were active, or has the evidence to support the existence of other major desert basins been lost for many periods throughout Earth history?
Becoming Less Illegal: Deservingness Frames and Undocumented Migrant Incorporation
Authors: Chauvin Sébastien , Garcés‐Mascareñas Blanca 
Published: April 2014

AbstractOver the last two decades, research on unauthorized migration has departed from the equation of migrant illegality with absolute exclusion, emphasizing that formal exclusion typically results in subordinate inclusion. Irregular migrants integrate through informal support networks, the underground economy, and political activities. But they also incorporate into formal institutions, through policy divergence between levels of government, bureaucratic sabotage, or fraud. The incorporation of undocumented migrants involves not so much invisibility as camouflage – presenting the paradox that camouflage improves with integration. As it reaches the formal level of claims and procedures, legalization brings up the issue of the frames through which legal deservingness is asserted. Looking at the moral economy embedded in claims and programs, we examine a series of frame tensions: between universal and particular claims to legal status, between legalization based on vulnerability and that based on civic performance, between economic and cultural deservingness, and between the policy level and individual subjectivity. We show that restrictionist governments face a dilemma when their constructions of “good citizenship” threaten to extend to “deserving” undocumented migrants. Hence, they may simultaneously emphasize deservingness frames while limiting irregular migrants’ opportunities to deserve, effectively making deservingness both a civic obligation and a civic privilege.
Middle‐Class Parents and Urban Public Schools: Current Research and Future Directions
Authors: Posey‐Maddox Linn , Kimelberg Shelley McDonough , Cucchiara Maia 
Published: April 2014

AbstractMiddle‐class flight from urban public schools to suburban districts or private schools is a key source of educational inequality. Recently, however, a number of studies have focused on middle‐class and upper‐middle‐class families who have made a different choice, opting to remain in the city and send their children to neighborhood public schools. While the movement of advantaged families into urban public schools has received positive attention in the media, this growing body of research tells a more complicated story. Middle‐class families – with their economic, cultural, and social capital – can bring important resources to schools, resulting in widespread benefits. However, their engagement in urban public schools can also lead to marginalization and exclusion. We review the emergent literature on this topic, highlighting four themes: (i) parent preferences, identities, and values; (ii) the role of marketing campaigns and informal networks in attracting the middle class; (iii) the nature and consequences of middle‐class parent engagement in urban schooling; and (iv) the relationship between neighborhood change and school change. We conclude by outlining a research agenda aimed at deepening our understanding of the mechanisms by which middle‐class parent engagement in urban schooling may serve to mitigate, reproduce, or exacerbate educational inequalities.
Computational fluid dynamics modelling of different detention pond configurations in the interest of sustainable flow regimes and gravity sedimentation potential
Authors: Tsavdaris Alexandros , Mitchell Steve , Williams John B. 
Published: April 2014

AbstractThis study presents the results of the flow regime evaluation, by means of computational fluid dynamics (CFD), of a vegetated detention pond located at Waterlooville, Hampshire, UK. Alternative pond layouts were assessed for the same flow conditions on the basis of recommendations made in the literature. The results were validated by comparing the maximum computational velocities for the same case using different numbers of mesh elements. It was found that the development of a CFD model of detention ponds is intricate but feasible. The main findings were: (i) The present design performed well in terms of flood risk management, but the flow patterns could result in questionable treatment efficiency; (ii) vegetation seems to promote horizontal recirculation and turbulence; (iii) triangular and elliptical pond designs showed very poor performance; (iv) the most appropriate design for the given location and hydrological regime is an elliptical pond with a central emergent/submerged island.
First glyphosate‐resistant Lolium spp. biotypes found in a European annual arable cropping system also affected by ACCase and ALS resistance
Authors: Collavo A , Sattin M 
Published: April 2014

SummaryIn Europe, glyphosate‐resistant weeds have so far only been reported in perennial crops. Following farmers' complaints of poor herbicide efficacy, resistance to glyphosate as well as to ACCase and ALS inhibitors was investigated in 11 populations of Lolium spp. collected from annual arable cropping systems in central Italy. Field histories highlighted that farmers had relied heavily on glyphosate, often at low rates, as well as in a non‐registered crop. The research aimed at elucidating the resistance status, including multiple resistance, of Lolium spp. populations through glasshouse screenings and an outdoor dose–response experiment. Target‐site resistance mechanism was also investigated for the substitutions already reported for EPSPs, ALS and ACCase genes. Three different resistant patterns were identified: glyphosate resistant only, multiple resistant to glyphosate and ACCase inhibitors and multiple resistant to glyphosate and ALS inhibitors. Amino acid substitutions were found at position 106 of the EPSPs gene, at position 1781, 2088 and 2096 of the ACCase gene and at position 197 and 574 of the ALS gene. Not all populations displayed amino acid substitutions, suggesting the presence of non‐target‐site‐mediated resistance mechanisms. After 39 years of commercial availability of glyphosate, this is the first report of multiple resistance involving glyphosate selected in annual arable crops in Europe. Management implications and options are discussed.
Experimental Improvement of Ejector Performance Through Numerical Optimization of Nozzle Geometry
Authors: Sharifi Navid , Sharifi Majid 
Published: April 2014

Ejectors are widely used in different applications such as refrigeration, propulsion, evacuation and aerospace. They use a pressurized flow as a motive stream to entrain a secondary flow or suction flow. In the current study, a malfunctioning steam ejector is studied experimentally to identify the sources of low compression ratio. This ejector was designed to operate under a motive pressure of 6 bar. However, the required vacuum in the system was not attained unless the pressure of motive steam was increased to 8 bar. The steam ejector was coupled with other unit operating facilities and hence, the ejector replacement was very costly. Therefore, the fastest and the most inexpensive way of improving the device performance was considered as replacing just the primary nozzle and without any further change in ejector’s geometry.
To achieve the required vacuum under the available motive pressure (i.e. 6 bar), a CFD–based optimization procedure was performed and different nozzle shapes were numerically investigated. The CFD Models were constrained to a fixed constant throat since the optimized nozzle shall not consume more flow rate than the former one. Ten different nozzle geometries were scrutinized in this numerical simulation and the one, which yields the highest entraining performance under the given boundary condition (i.e. motive flow pressure of 6 bar), was selected as the most optimized nozzle and manufactured. After installing the designed nozzle, an improved entrainment capability was observed and a desired vacuum level was attained under the nominal pressure of 6 bar.
Harvesting Downstream Energy to Improve Efficiency: Creating Apparent Discharge Coefficients of Jet Nozzles Greater Than 1.3
Authors: Surjaatmadja Jim B. , McDaniel Billy W. , Pawar Bharat B. 
Published: April 2014

Fluid movement devices use upstream energy to move fluid from one location to another. Flow nozzles that slightly accelerate fluid motion, especially into the same direction, often exhibit discharge coefficients greater than 1.0. Jet nozzles, however, by definition, create a jet stream that is much faster than the upstream fluid, often exceeding 100-fold higher velocities. Energy used to move this fluid is often very high; jetting efficiencies are generally less than 1.0 and will only approach 1.0 if the shape of the entrance is such that there is no “vena contracta” within its flow regime inside the nozzle.
High-pressure nozzles require high horsepower to generate high-velocity fluids. As is commonly performed, power is created using high-powered pumping equipment. Oftentimes, nozzles are used to jet in locations that have high ambient pressures, such as at the bottom of the ocean or inside a deep oil well. At these locations, the hydrostatic pressures could be very high. Pressure at the upstream side of the nozzle would be even higher.
This paper discusses the design and use of a unique nozzle that uses the hydrostatic (potential) energy to accelerate the fluid velocity of the jet. In essence, the nozzle uses the downstream energy to perform part of its job, thus, substantially reducing the upstream pressure requirement. This phenomenon was proven to occur using CFD analysis. Laboratory tests have shown apparent discharge coefficients between 1.38 and 1.69, depending on the downstream pressure.
Integration of Computer Aided Design Analysis Into the Engineering Design Process for Use by Engineering Designers
Authors: Petersson Håkan , Motte Damien , Eriksson Martin , Bjärnemo Robert 
Published: April 2014

When developing products, engineering designers often face the problem that their candidate for a technical solution, ranging from a concept to a detailed design, needs to be analyzed by a design analyst before it is approved or rejected and the engineering designer can continue his/her activities within the product development process. If engineering designers have to send every solution candidate to a design analyst, a lot of time and money is lost. To avoid this, some Swedish companies have started to allow their engineering designers to use the analysis capabilities imbedded in modern CAD/CAE software.
In the literature on product development and on computer based design analysis (CBDA) both processes are fairly well described. However, this cannot be said about the interaction between the two processes. This is a growing issue as it represents core knowledge for developing efficient and effective integration concepts, which in turn can be developed into likewise efficient and effective approaches on how to assist the engineering designer to perform parts of the CBDA process on his/her own. Note that when we refer to CBDA here, this is confined to the use of FEM in the development of products, primarily based on working principles originating from the area of Mechanical Engineering.
Since we have been working on a process model for the integration between engineering design and design analysis, this has inspired us to utilize findings from these efforts to propose a conceptual model for a design analysis process driven by the engineering designer to be integrated into the product development process.
The proposed design analysis process model is based on the use of predefined analysis methods or templates. Templates are also utilized for QA (Quality Assurance) and monitoring of the analysis activities. Responsible for the development of the analysis methods and the templates are expert design analysts, who develop these tools within a technology development process. Before allowing the engineering designers access to them, these tools need to be approved by relevant bodies within the industrial enterprise and/or by external sources such as those responsible for certification and risk management.
In this paper we present the development of the proposed integrated design analysis process model and an industrial case study, which incorporates a non-linear design analysis activity, utilizing the FEM-program Abaqus within the CAD-software Catia V5 and its imbedded optimization module.
Numerical Investigations of the Positive Effects of Vehicle Dynamics Control Systems on Vehicle Crash
Authors: Elkady Mustafa , Elmarakbi Ahmed , MacIntyre John , El-Hage Hicham 
Published: April 2014

This paper focuses on the use of vehicle dynamics control systems (VDCS) to mitigate vehicle collisions in case of offset frontal vehicle-to-barrier crash scenario. A unique six-Degree-of-Freedom (6-DOF) vehicle dynamics/crash mathematical model is developed and analysed in this paper. The model is used to define the vehicle body crash parameters by integrating a vehicle dynamics model with a vehicle front-end structure model. In this model, the anti-lock braking system (ABS) and the active suspension control system (ASC) are co-simulated with the full car vehicle dynamics model and integrated with the front-end structure. The associated equations of motion of the model are developed and solved numerically.
In this study, different crash scenarios are simulated with different cases of VDCS to investigate their influences on the vehicle collision improvement. ABS, ASC, and anti-pitch control (APC) systems as well as an under pitch control (UPC) technique are applied in this paper, and their results are compared with free rolling crash scenarios. This study shows that the vehicle dynamics/crash response is captured and analysed quickly and accurately. Furthermore, it is shown that the VDCS affect the crash characteristics positively.
Effect of Different Italian Regulatory Frameworks on the Energetic Assessment of CHP Plants: A Comparative Design and Experimental Condition Analysis
Authors: Badami Marco , Bocci Giacomo , Camillieri Francesco , Pagliarulo Davide , Portoraro Armando , Vigliani Elisa 
Published: April 2014

Since a Combined Heat and Power (CHP) plant can offer high economic benefits when a certain energy savings value is obtained, it is very interesting to consider the requirements foreseen by legislation to meet this target. The paper deals with an energetic assessment of eleven industrial CHP power plants, based on different prime mover technologies installed and in operation in Italy. The analysis has been carried out considering not only the nominal design data of the plants, but also experimental ones, in order to highlight their real operational performances.
The aim of the study was to compare the effects of two legislations on the calculation of the primary energy savings: the first is the Italian legislation that was in force when the power plants were designed, and the second is the current European Directive, which was issued a few years later when the plants were already in operation. The results of the study show as the subsidy mechanism introduced by the new legislation is stricter than the previous one, and could have a significant effect on the economic profitability of a cogeneration plant installation. More critical comments on the overall regulatory framework are presented in the paper.
Carbon Fiber Composite Materials in Modern Day Automotive Production Lines: A Case Study
Authors: Petersson Håkan , Motte Damien , Bjärnemo Robert 
Published: April 2014

New and innovative production equipment can be developed by introducing lightweight materials in modern day automotive industry production lines. The properties of these new materials are expected to result in improved ergonomics, energy savings, increased flexibility and more robust equipment, which in the end will result in enhanced productivity. Carbon composite materials are one such alternative that has excellent material properties. These properties are well documented, and the market for carbon composite materials is growing in many areas such as commercial aircrafts, sporting goods and wind turbines. However, when studying the use of carbon composite materials for production equipment in the automotive industry, it was found that there were few, if any, such examples.
This paper focuses on innovative ways of making carbon composite materials available for designing automotive industry production equipment by introducing a design and material concept that combines flexibility, relatively low costs and high functionality. By reducing the weight by 60%, it was obvious that the operators were very positive to the new design. But just as important as the improvement of the ergonomic feature, the combination of low weight and material properties resulted in a more robust design and a more stable process of operation. The two main designs (two versions of the steel-based design were constructed) were developed sequentially, making it difficult to compare development costs since knowledge migrated from one project to the next. In this study, the gripper was manufactured in both carbon composite material and steel. The different designs were compared with reference to design costs, functionality, robustness, product costs and ergonomics. The study clearly shows that the composite material represents a favorable alternative to conventional materials, as the system combines superior properties without significantly increasing the cost of the equipment. This paper describes the approach in detail.
Flat-Plate Solar Collector in Transient Operation: Modeling and Measurements
Authors: Saleh Ahmad M. , Mueller Donald W. , Abu-Mulaweh Hosni I. 
Published: April 2014

Solar energy is a viable alternative to limited fossil fuel resources. One of the simplest and most direct applications of this energy is the conversion of solar radiation into thermal energy with a flat-plate solar collector which can be used in water-heating systems. This paper presents a mathematical model for simulating the transient processes which occur in liquid flat-plate solar collectors. A discrete nodal model that represents the flat-plate solar collector’s layers and the storage tank is employed. The model is based on solving a system of coupled differential equations which describe the energy conservation for the glass cover, air gap, absorber, fluid, insulation, and the storage tank. Inputs to the model include the time-varying liquid flow rate, incident solar radiation, and ambient air temperature, as well as the volume of liquid in the storage tank and initial temperature of the solar collector and tank. The system of differential equations is solved iteratively using an implicit, finite-difference formulation executed with MATLAB software. In order to verify the proposed method, an experiment was designed and conducted on different days with variable ambient conditions and flow rates. The comparison between the time-varying computed and measured fluid temperature at the collector outlet shows good agreement.
The proposed method is extremely general and flexible accounting for variable ambient conditions and flow rates, as well as allowing for a geometrical and thermophysical description of all essential components of the solar collector system, including the storage tank. The validated and verified, general model is suitable to investigate the effectiveness of various components without the necessity of carrying out experimental work, and the flexible computational scheme is useful for transient simulations of energy systems.