bluuebunny/crossref_metadata_2025 huggingface dataset:
Runaway electrons as a source of impurity and reduced fusion yield in the dense plasma focus
Authors: Lerner Eric J. , Yousefi Hamid R.
Published: October 2014

Impurities produced by the vaporization of metals in the electrodes may be a major cause of reduced fusion yields in high-current dense plasma focus devices. We propose here that a major, but hitherto-overlooked, cause of such impurities is vaporization by runaway electrons during the breakdown process at the beginning of the current pulse. This process is sufficient to account for the large amount of erosion observed in many dense plasma focus devices on the anode very near to the insulator. The erosion is expected to become worse with lower pressures, typical of machines with large electrode radii, and would explain the plateauing of fusion yield observed in such machines at higher peak currents. Such runaway electron vaporization can be eliminated by the proper choice of electrode material, by reducing electrode radii and thus increasing fill gas pressure, or by using pre-ionization to eliminate the large fields that create runaway electrons. If these steps are combined with monolithic electrodes to eliminate arcing erosion, large reductions in impurities and large increases in fusion yield may be obtained, as the I4 scaling is extended to higher currents.
Perovskite-kesterite monolithic tandem solar cells with high open-circuit voltage
Authors: Todorov Teodor , Gershon Talia , Gunawan Oki , Sturdevant Charles , Guha Supratik
Published: October 2014

We report a monolithic tandem photovoltaic device with earth-abundant solution processed absorbers. Kesterite Cu2ZnSn(S,Se)4 and perovskite CH3NH3PbI3 solar cells were fabricated monolithically on a single substrate without layer transfer. The resulting devices exhibited a high open circuit voltage (Voc) of 1350 mV, close to the sum of single-absorber reference cells voltages and outperforms any monolithic tandem chalcogenide device (including Cu(In,Ga)Se2) reported to date. Ongoing optimization of several device elements including the severely limiting top contact electrode is expected to yield superior currents and efficiency. Importantly, our device architecture demonstrates the compatibility and synergistic potential of two of the most promising emerging photovoltaic materials and provides a path for optimization towards >20% efficiency.
Interleukin 1 receptor-associated kinase 1 (IRAK1) mutation is a common, essential driver for Kaposi sarcoma herpesvirus lymphoma
Authors: Yang Dongmei , Chen Wuguo , Xiong Jie , Sherrod Carly J. , Henry David H. , Dittmer Dirk P.
Published: October 2014

Significance

Primary effusion lymphoma (PEL) is an AIDS-defining cancer. It is associated with Kaposi sarcoma-associated herpesvirus. To date, no sequencing studies have been conducted for this cancer. We used X chromosome-targeted next-generation sequencing to identify 33 genes with coding region mutations in 100% of cases, including in interleukin 1 receptor-associated kinase 1 (IRAK1). IRAK1 kinase modulates toll-like receptor signaling-mediated immune signaling. It binds to MyD88 adapter protein, which is mutated in a subset of diffuse large B-cell lymphomas. IRAK1, however, had not been linked to cancer. This IRAK1 mutant is constitutively active and essential for PEL survival. This highlights the importance of innate immunity signaling as drivers for cancer, particularly those caused by viruses. It also suggests IRAK1 kinase may be a potential target for therapy.
The Trumanite Network
Authors: Glennon Michael J.
Published: October 2014

This chapter describes the origins, operation, and characteristics of the Trumanite network that defines and manages U.S. security policy. The network emerged during the Truman administration, with the support of liberal democrats in Congress and over the opposition of conservative Republicans, who expressed concern about creating a “Gestapo” or “garrison state” run by “power-grabbing bureaucrats.” The tightly knit network consists today of the several hundred officials who run the nation’s vast military, intelligence, law enforcement, and diplomatic apparatus, which is largely removed from public view. They are expert, efficient, hard-working, secretive, nonideological, and process-oriented, inclined to stick with existing policy, define security in military terms, exaggerate security threats, eschew dissent, and resist accountability. The gravitational pull leads to groupthink, excessive path dependence, and security programs that are “sticky down.”
BBGKY Hierarchy, Kinetic Theories and the Boltzmann Equation
Authors: Campa A. , Dauxois T. , Fanelli D. , Ruffo S.
Published: October 2014

This chapter introduces to the study of the dynamics of many-body systems. The reduced distribution functions and their dynamics, determined by the equations of the BBGKY hierarchy, are presented. It is explained how kinetic theories are based on plausible approximations of the first equations of the hierarchy; this leads to a truncation of the hierarchy and to a closed equation for the one-particle distribution function. The derivation of the Boltzmann equation, suitable for diluted short-range systems, is then offered in detail. Through the study of the important H-theorem, it is shown that the macroscopic irreversibility is built upon in the kinetic equations. The apparent contradiction with the reversibility of the microscopic equations of motion is resolved by the appropriate interpretation of the physical meaning of the collisional term of the kinetic equations.
Out-of-Equilibrium Dynamics and Slow Relaxation
Authors: Campa A. , Dauxois T. , Fanelli D. , Ruffo S.
Published: October 2014

In this Chapter the peculiar out-of-equilibrium behaviour of systems subject to long-range coupling is discussed. The existence of the so called quasi stationary states (QSS) is numerically demonstrated using the Hamiltonian Mean Field model as a reference case study. The process of relaxation of a test particle in contact with a thermal reservoir is studied and shown to yield a Fokker Planck equation at the leading order of a system size expansion. The emergence of QSS is then analyzed in terms of attractive Vlasov equilibria. The statistical maximum entropy theory pioneered by Lynden-Bell allows one to explicitly calculate the equilibrium solution of the Vlasov equation and quantitatively explain the QSS features. The method is successfully applied to the HMF model and shown to predict out-of-equilibrium phase transitions from magnetized to homogeneous phases. The core halo solution, an alternative approach to the QSS, is finally reviewed.
Two-Dimensional and Geophysical Fluid Mechanics
Authors: Campa A. , Dauxois T. , Fanelli D. , Ruffo S.
Published: October 2014

In this Chapter the statistical mechanics theory of long-range interactions is applied to hydrodynamics problems. The Euler equation is derived as a limiting case of the two dimensional Navier-Stokes equation for incompressible fluids. A logarithmic coupling between distant vortices is found, an observation which points to the long-range character of the interactions. The Onsager point vortex model is then introduced and its statistical mechanics treatment reviewed. Moreover, the Robert-Sommeria-Miller theory for the 2D Euler equation is discussed. Finally, the quasi-geostrophic model is presented and a statistical mechanics theory developed to explain the formation of coherent structures in geophysical fluid dynamic (as seen in e.g. planets’ atmosphere and oceans).
Escape trajectories are deflected when fish larvae intercept their own C-start wake
Authors: Li Gen , Müller Ulrike K. , van Leeuwen Johan L. , Liu Hao
Published: October 2014

Fish larvae may intercept their own wake during sharp turns, which might affect their escape performance. We analysed C-starts of larval zebrafish (Danio rerio, Hamilton, 1822) using a computational fluid dynamics approach that simulates free swimming (swimming trajectory is determined by fluid forces) by coupling hydrodynamics and body dynamics. The simulations show that fish may intercept their own wake when they turn by 100–180°. During stage 1 of a C-start, the fish generates a strong jet at the tail that is shed into the wake. During stage 2, the fish intercepts this wake. Counterfactual simulations showed that wake interception increased the lateral force on the fish and reduced the fish's turning angle by more than 5°. Wake interception caused no significant acceleration tangential to the trajectory of the fish and did not affect total power output. While experimental and simulation evidence suggests that fish larvae can either undershoot or intercept but not overshoot their wake, our simulations show that larger fish might be able to avoid intercepting their wake by either under- or overshooting. As intercepting its own wake modifies the fish's escape trajectory, fish should account for this effect when planning their escape route.
Key messages and message integrity as concepts and metrics in communication evaluation
Authors: E. Carroll Craig , C. Huang-Horowitz Nell , Weberling McKeever Brooke , Williams Natalie
Published: October 2014

Purpose

– The purpose of this paper is to introduce the concepts of key messages and key message integrity, and examines their viability for communication management scholars and practitioners in evaluating media relations activities. Key message integrity addresses not only what messages transfer, but also how well.

Design/methodology/approach

– The authors analyzed 18 nonprofit organizations’ key messages and the messages’ integrity levels using content analysis on one month of their news coverage. In-depth interviews with eight of their media relations practitioners helped validate the concepts and the results.

Findings

– The authors found five unique categories and functions of key messages: information concerned with dissemination, raison d’être concerned with purpose, categories concerned with positioning, resource management concerned with accounting for resources, and social relevance concerned with legitimacy. Findings also revealed varying levels of transmission and message integrity across the categories. Interviews revealed insights into challenges for communicating organizational key messages to the news media.

Originality/value

– This study lays the foundation for additional research on key messages and key message integrity as useful metrics for communication management scholars and practitioners.
A framework for advanced social media exploitation in government for crowdsourcing
Authors: Spiliotopoulou Lefkothea , Charalabidis Yannis , N. Loukis Euripidis , Diamantopoulou Vasiliki
Published: October 2014

Purpose

– This paper aims to develop and evaluate, in “real-life” pilot applications, a framework for advanced social media exploitation by government agencies in their policy-making processes to promote public participation and conduct crowdsourcing.

Design/methodology/approach

– This framework has been developed through cooperation with public sector employees experienced in public policy-making, using both qualitative and quantitative techniques: semi-structured focus group discussions, scenarios development and questionnaire surveys. The evaluation of the framework has been conducted through semi-structured focus group discussions with public sector employees involved in the pilot applications.

Findings

– A framework has been developed for advanced social media exploitation by government agencies, which is based on the automated posting of policy-related content to multiple social media, and then retrieval and processing of citizens’ interactions with it (e.g. views, likes, comments and retweets), using the application programming interfaces (API) of these social media. Furthermore, a supporting information and communication technologies (ICT) infrastructure and an application process model for it were developed. Its evaluation, based on “real-life” pilot applications, leads to useful insights concerning its capabilities, strengths and weaknesses.

Research limitations/implications

– The proposed framework has been evaluated in a small number of pilot applications, so further evaluation of it is required, in various types of government agencies and for different kinds of policy consultations.

Practical/Implications

– The above framework enables government agencies to communicate with wider and more heterogeneous audiences in a short time and at a low cost, increase public participation in their policy-making processes, collect useful knowledge, ideas and opinions from citizens and, finally, design better, more socially rooted, balanced and realistic policies.

Originality/value

– This research contributes to the development of knowledge concerning advanced practices for effective social media exploitation in government (which is currently limited, despite the considerable relevant knowledge developed in this area for the private sector), by developing and evaluating a framework for advanced and highly automated exploitation of multiple social media by government agencies. Furthermore, an evaluation methodology for such practices has been developed, which is based on sound theoretical foundations.
High consumption of pulses is associated with lower risk of abnormal glucose metabolism in women in Mauritius
Authors: Wennberg M. , Söderberg S. , Uusitalo U. , Tuomilehto J. , Shaw J. E. , Zimmet P. Z. , Kowlessur S. , Pauvaday V. , Magliano D. J.
Published: October 2014

Aims

To investigate if consumption of pulses was associated with a reduced risk of developing abnormal glucose metabolism, increases in body weight and increases in waist circumference in a multi‐ethnic cohort in Mauritius.

Methods

Population‐based surveys were performed in Mauritius in 1992 and in 1998. Pulse consumption was estimated from a food frequency questionnaire in 1992 and outcomes were measured in 1998. At both time points, anthropometry was undertaken and an oral glucose tolerance test was performed.

Results

Mauritian women with the highest consumption of pulses (highest tertile) had a reduced risk of developing abnormal glucose metabolism [odds ratio 0.52; 95% CI 0.27, 0.99) compared with those with the lowest consumption, and also after multivariable adjustments. In women, a high consumption of pulses was associated with a smaller increase in BMI.

Conclusions

High consumption of pulses was associated with a reduced risk of abnormal glucose metabolism and a smaller increase in BMI in Mauritian women. Promotion of pulse consumption could be an important dietary intervention for the prevention of Type 2 diabetes and obesity in Mauritius and should be examined in other populations and in clinical trials.
Effect of controlled hypoglycaemia on sympathetic skin response in patients with Type 1 diabetes and control subjects
Authors: Koivikko M. L. , Airaksinen K. E. J. , Perkiömäki J. S. , Huikuri H. V. , Tapanainen J. S. , Kallio M. A.
Published: October 2014

Aim

To evaluate the quantity and mechanism of sudomotor function during euglycaemia and hypoglycaemia using sympathetic skin responses in patients with Type 1 diabetes and control subjects.

Methods

Sympathetic skin responses were measured in 16 patients with diabetes without neuropathy and in eight control subjects during euglycaemic and hypoglycaemic clamp.

Results

During hypoglycaemia, the number of repetitive synchronous sympathetic skin responses significantly increased in both groups (P<0.05), and this increase was significantly associated with the hypoglycaemia and sweating.

Conclusions

During hypoglycaemia the number of repetitive synchronous sympathetic skin responses was related to increased sweating according to the hypoglycaemic symptom score. This is best explained by central nervous system reactions. The sympathetic skin responses of the patients with Type 1 diabetes had a weaker correlation with hypoglycaemia and its symptoms, which was possibly attributable to an adaptation or a dysfunction of the patients' sudomotor pathways.
An Analysis of Makovsky's Border Proposal in Light of Palestinian Needs
Authors: Wilson Andrew M.
Published: October 2014

The border proposal of David Makovsky, who, served as an advisor to Martin Indyk during the recent Israeli‐Palestinian peace talks, is analyzed from the standpoint of viable contiguity — the degree to which the border, particularly where there is Israeli annexation of settlement blocs, offers provision for access, living space, and transportation infrastructure for the Palestinian population in adjacent areas. While at some locales his proposed border improves contiguity for Palestinians compared with the current situation unilaterally imposed by Israel, more attention needs to be given to the ways it would adversely affect the quality of life of the Palestinian population in the cities and villages adjacent to those settlement blocs. This leads to the suggestion that a more comprehensive solution to border issues will feature the establishment of joint economic zones and binational administrative authorities, which can manage the entanglement of roads and populations in ways that will maximize the potential for economic development.
Mostafa Malekian: Spirituality, Siyasat‐Zadegi and (A)political Self‐Improvement
Authors: Sadeghi‐Boroujerdi Eskandar
Published: October 2014

Mostafa Malekian has yet to receive much attention in Western academic literature pertaining to Iranian intellectual life, but inside Iran, he has emerged as a popular public intellectual; seen as both a culmination of and rupture with the project of “religious intellectualism.” Rather than offer a revolutionary and politically engaged vision of Islam, or a “reformist” or “democratic” interpretation of Shi῾ism, his project seeks to integrate what he calls “rationality” (῾aqlaniyat) and “spirituality” (ma᾽naviyat). As Malekian's project has developed, it has broken, in a number of important respects, with mainstream Islam as practiced in Iran, the religious reformist project, and even organized religion as a whole. This article seeks not only to offer one of the first comprehensive analysis of his existential and social thought in English, but also to analyze his project's deep affinities with a pervasive fatigue vis‐à‐vis collective projects of political emancipation and even “politics” tout court, in the latter phases of the “reformist” President Hojjat al‐Islam Seyyed Mohammad Khatami's tenure.
Indicated prevention with long‐chain polyunsaturated omega‐3 fatty acids in patients with 22q11DS genetically at high risk for psychosis. Protocol of a randomized, double‐blind, placebo‐controlled treatment trial
Authors: Armando Marco , De Crescenzo Franco , Vicari Stefano , Digilio Maria Cristina , Pontillo Maria , Papaleo Francesco , Amminger G. Paul
Published: October 2014

Aim

It has been found that long‐chain omega‐3 polyunsaturated fatty acids (PUFAs) reduce the risk of progression to first episode of psychosis (FEP) and may offer a safe and efficacious strategy for selective and indicated prevention in young people with ultra‐high‐risk (UHR) states. An opportunity for exploring the trajectory of FEP and for investigating the efficacy of preventive treatments exists in 22q11.2 deletion syndrome (22q11DS), which has a 30% psychotic transition rate. The fact that 22q11DS patients are more homogeneous than other UHR groups and are characterized by high level of negative symptoms provides a strong rationale for the use of PUFAs. The principal aim of the present trial is to investigate the effects of PUFAs in individuals with 22q11DS who are at UHR for developing FEP.

Methods

A prospective, randomized, double‐blind, placebo‐controlled, single‐centre study design will be used. Eighty individuals aged 12–26 will be randomly assigned to two treatment conditions.

Results

The experimental group will receive PUFAs. The placebo group will receive paraffin oil. Standard clinical assessments and neuropsychological tests will be performed at baseline and at 8‐, 12‐, 26‐ and 52‐week follow‐up. Blood samples will be collected at baseline and after 12 weeks. This study is registered as an International Standard RCT, number 02070211. The corresponding author is supported by a NARSAD Young Investigator Award.

Conclusions

This is the protocol of a planned study that aims to test the efficacy of PUFAs in the prodromal phase of FEP, in a specific syndrome where there is strong evidence that a high genetic load is involved in the disorder.
The EU's Post‐Lisbon Free Trade Agreements: Commercial Interests in a Changing Constitutional Context
Authors: Gstöhl Sieglinde , Hanf Dominik
Published: October 2014

This article examines how the Common Commercial Policy in the post‐Lisbon era impacts citizens' rights both within the EU and in the partner countries. The EU's aspiration to pursue a normative agenda through trade has further been reinforced by the Lisbon Treaty, both with regard to the objectives of external action and the reformed trade policy‐making processes. Concurrently, however, the EU has refocused its trade strategy on growth and competitiveness, and strongly advocated the conclusion of ‘new generation’ free trade agreements. These agreements combine an ambitious ‘WTO‐plus’ agenda with normative issues such as provisions on human rights, a social dimension and sustainable development. The result of this dual approach is a mixed ‘constitutional balance’: whereas constitutional rights and competitiveness have the potential to reinforce each other with positive synergy effects, they may also result in tensions and policy incoherencies.
Protecting Human Rights in the Context of Free Trade? The Case of the SADC Group Economic Partnership Agreement
Authors: Gammage Clair
Published: October 2014

As free trade agreements proliferate, the relationship between trade and human rights continues to attract attention across academic disciplines. The linkages between human rights and liberal trade rules have been the subject of debate for some time. Since most countries tend to afford constitutional protection to both human rights and freedom of trade, there appears to be an inescapable connection between the two regimes. In theory, at least, economic growth should improve human rights standards and conditionality can be one way through which human rights compliance is achieved. However, in practice, States often pursue economic objectives that conflict with their human rights obligations. This article explores the linkages and potential conflicts between human rights and trade in the context of regional trade agreements, with a focus on the interim Economic Partnership Agreement between the European Union and the Southern African Development Community Group.
Dispersal potential impacts size clines of grasshoppers across an elevation gradient
Authors: Levy Richard A. , Nufio César R.
Published: October 2014

Body size is a life history trait that determines the reproductive success of a variety of organisms. Changes in body size may have a genetic component when persistent conditions such as season length and climate select for individuals of an optimal body size and an environmental component when it is influenced on an ecological scale by factors such as weather, food availability, or maternal effects. Along elevational gradients that experience seasonality, insects commonly become smaller with increases in elevation. In this study we test the hypothesis that dispersal potential, an indicator of gene flow, impacts the type of size clines exhibited by insects along elevational gradients and that these differences in local adaptation should lead to predictable changes in their reproductive potential and output. Using two short winged grasshopper species, Aeropedellus clavatus and Melanoplus boulderensis, and two long winged species, Camnula pellucida and Melanoplus sanguinipes, we showed that species with low dispersal potential are associated with significant declines in body size with increases in elevation while species with high dispersal potential displayed no size clines. Consistent with short winged species being more locally adapted, we show that reproductive potential, as measured by the proportion of ovarioles that become functional, do not differ among populations of short winged species, but decline with elevation in the long winged species. While our study failed to show that dispersal potential impacts reproductive output in a consistent and predictable manner (as measured by clutch and egg sizes), we address the possibility that clutch size may not reflect changes in total reproductive output and that changes in egg size may be a plastic trait. We concluded that studies exploring the evolution of body size, the reproductive capacity and species level responses to environmental change should note the importance of dispersal potential in influencing these patterns.
Are general dental practitioners confident in primary care oral surgery service?
Authors: Askar W. , Crean S.
Published: October 2014

Aims

This study aims to evaluate general dental practitioner's confidence in a primary care oral surgery service; assess patterns of referral; and their level of satisfaction and identify those procedures deemed inappropriate for referral to such a service.

Materials and methods

A postal questionnaire was distributed to (n = 70) dentists who refer to a primary care oral surgery service in the north‐west of England.

Results

One hundred per cent of respondents (n = 58) indicated that they were confident in the service. Overall satisfaction with the service was: very good 80% and good 20%. Satisfaction was correlated with: treatment outcome: rs = 0.53; n = 54; P < 0.01; ratings of patient experience: rs = 0.56; n = 54; P < 0.01; and rating of post‐operative care arrangements: rs = 0.38; n = 54; P < 0.01. Factors affecting a decision to refer were: complexity of treatment (85%); operator experience (79%); waiting time (63%); treatment without patient charges (28%); and facilities and equipment (32%). Procedures viewed as not appropriate for referral: management of cranio‐facial pain (30%); diagnosis of white patches, soft tissue lesions and ulcers (30%); and management of trauma (21%).

Conclusions

Levels of confidence and satisfaction among referring dental practitioners with the primary care oral surgery service were most strongly related to ratings of patient experience. Decisions to refer were based on patient experience and treatment complexity. Overall satisfaction remained very high.
Mechanisms and treatments of photoaging
Authors: Poon Flora , Kang Sewon , Chien Anna L.
Published: October 2014

Photoaging is frequently encountered in a dermatologic practice. This systematic literature review aims to explore the etiology of photoaging and address the evidence behind its current management. A comprehensive search of MEDLINE, EMBASE, UpToDate, and the Cochrane Library was conducted. Articles were limited to those relating to photoaging. There are two major approaches in the current management of photoaging. This includes strategies to prevent against ultraviolet damage (e.g. sunscreen) and medications that attempt to reverse existing skin damage (topical retinoids and 5‐fluorouracil). There has been a large growth in the variety of treatment options in recent years. While it is important for such growth to continue, prevention via sensible photoprotection methods still remains the best current management option.
Back to Black
Authors: Calosi Claudio , Varzi Achille C.
Published: October 2014

This is a brief sequel to Max Black's classic dialogue on the Identity of Indiscernibles. Interlocutor A defends the bundle theory by endorsing the (by now popular) view according to which Black's world does not contain two indiscernible spheres but rather a single, bi‐located sphere. His opponent, B, objects that A cannot distinguish such a world from a world with a single, uniquely located sphere, hence that the view in question adds nothing to A's original response to Black's challenge. A is simply denying that there can be worlds with two or more indiscernible entities.
Synaptic Vesicle Generation from Central Nerve Terminal Endosomes
Authors: Kokotos Alexandros C. , Cousin Michael A.
Published: October 2014

Central nerve terminals contain a small number of synaptic vesicles (SVs) that must sustain the fidelity of neurotransmission across a wide range of stimulation intensities. For this to be achieved, nerve terminals integrate a number of complementary endocytosis modes whose activation spans the breadth of these neuronal stimulation patterns. Two such modes are ultrafast endocytosis and activity‐dependent bulk endocytosis, which are triggered by stimuli at either end of the physiological range. Both endocytosis modes generate endosomes directly from the nerve terminal plasma membrane, before the subsequent production of SVs from these structures. This review will discuss the current knowledge relating to the molecular mechanisms involved in the generation of SVs from nerve terminal endosomes, how this relates to other mechanisms of SV production and the functional role of such SVs.
Low Cycle Fatigue Evaluation of Pipe Bends With Local Wall Thinning Considering Multi-Axial Stress State
Authors: Urabe Yoshio , Takahashi Koji , Abe Hisanori
Published: October 2014

Low cycle fatigue tests and finite element (FEM) analysis were conducted using 100A pipe bend specimens made of STPT410 carbon steel with and without local wall thinning local wall thinning was machined on the inside of the elbow and was prepared at extrados, crown, and intrados. The parameters of the wall thinning were same (the wall thinning ratio = 0.5, the wall thinning angle = 180 deg, and the wall thinning length = 100 mm) in the all test cases. The pipe bend specimens were subjected to the prescribed cyclic in-plane bending displacement with constant internal pressure of 0–12 MPa. Also, low cycle fatigue tests using sound pipe bend specimens were carried out for comparison. According to the test results, low cycle fatigue strength of wall thinned pipe bend specimens was not so different, regardless of location of wall thinning. Low cycle fatigue strength of the pipe bend specimens was beneath the best fit fatigue curve and its reason can be explained quantitatively by a proposed cumulated damage rule introducing ductility exhaustion considering multi-axial stress state. The validity of the new proposed cumulative damage rule was also confirmed by the another sample analysis using other reference data obtained by pre-overloaded in-plane cyclic bending tests.
Understanding the Effect of Heat Input and Sheet Gap on Porosity Formation in Fillet Edge and Flange Couch Laser Welding of AC-170PX Aluminum Alloy for Automotive Component Manufacture
Authors: Alshaer A. W. , Li L. , Mistry A.
Published: October 2014

An investigation is reported on the characteristics of porosity formation in high power disk laser welding of AC-170PX (AA6014) alloy sheets (coated with titanium and zirconium) in two weld joint configurations: fillet edge and flange couch with AA4043 filler wire for potential automotive manufacturing applications. Porosity, macro- and microstructure characteristics, tensile strengths, microhardness, and joint geometry were investigated. It has been found that an increase in heat input and welding speed generates more porosity in both types of joints. The introduction of a 0.2 mm gap reduces porosity significantly in the fillet edge joints but it does not have noticeable effect on the flange couch joints. The mechanism of the porosity formation is discussed.
Bending Behavior of Reinforced Thermoplastic Pipe
Authors: Bai Yong , Yu Binbin , Cheng Peng , Wang Nuosi , Ruan Weidong , Tang Jiwei , Babapour A.
Published: October 2014

Reinforced thermoplastic pipe (RTP) is a composite thermoplastic pipe, which is increasingly being used in oil and gas industry. In practical applications, RTPs inevitably experience bending during reeling process and offshore installation. The ovalization instability of RTP under pure bending was investigated. Several fundamental assumptions of RTP were proposed from the engineering application point of view. Then, based on nonlinear ring theory initially proposed by Kyriakides et al., the effect of transverse deformation through the thickness was introduced, and the ovalization growth of cross section during bending was studied according to nonlinear kinematics. The formulation was based on the principle of virtual work and was solved by a numerical solution. Inelastic material behavior of high density polyethylene (HDPE) was included, and a simplified method was proposed to simulate the behavior of fiber reinforced layer. A detailed Abaqus model was established using solid and truss elements to simulate the HDPE layer and reinforced fiber, respectively. The results obtained from the theoretical method were compared with Abaqus simulation results and test data of verification bending experiment and the results show excellent agreement. The proposed methods are helpful for RTP's engineering applications.
Cylindrical Thermal Cloak Based on the Path Design of Heat Flux
Authors: Wu Linzhi
Published: October 2014

When heat flux flows in a given medium, its path will solely be determined. This implies that material parameters determined by the predesigned path of heat flux will guide heat to flow along the designed path. Based on this idea, we develop a new method for the design of the cylindrical thermal cloak which can make heat flux detour the cloaked object. For the inhomogeneous anisotropic medium, we derive the relation between the path trajectory of heat flux and material parameters and obtain two differential equations and one boundary condition which are used to determine material parameters in the cylindrical cloak. The transient behavior on the flow of heat flux is simulated by Comsol Multiphysics and the transient thermal protection of the cylindrical cloak for the cloaked object is examined. The effect of the product of density and specific heat on the dynamic diffusion process of heat flux is analyzed. Since one can flexibly design the path of heat flux in the cloak, it has the large degree of freedom to construct thermal cloaks with the specific distributions of material parameters. The present method provides a new blue print for the transient thermal protection of a specific target.
Selective Laser Melting Additive Manufacturing of Novel Aluminum Based Composites With Multiple Reinforcing Phases
Authors: Gu Dongdong , Chang Fei , Dai Donghua
Published: October 2014

The selective laser melting (SLM), due to its unique additive manufacturing (AM) processing manner and laser-induced nonequilibrium rapid melting/solidification mechanism, has a promising potential in developing new metallic materials with tailored performance. In this work, SLM of the SiC/AlSi10Mg composites was performed to prepare the Al-based composites with the multiple reinforcing phases. The influence of the SLM processing parameters on the constitutional phases, microstructural features, and mechanical performance (e.g., densification, microhardness, and wear property) of the SLM-processed Al-based composites was studied. The reinforcing phases in the SLM-processed Al-based composites included the unmelted micron-sized SiC particles, the in situ formed micron-sized Al4SiC4 strips, and the in situ produced submicron Al4SiC4 particles. As the input laser energy density increased, the extent of the in situ reaction between the SiC particles and the Al matrix increased, resulting in the larger degree of the formation of Al4SiC4 reinforcement. The densification rate of the SLM-processed Al-based composite parts increased as the applied laser energy density increased. The sufficiently high density (∼96% theoretical density (TD)) was achieved for the laser linear energy density larger than 1000 J/m. Due to the generation of the multiple reinforcing phases, the elevated mechanical properties were obtained for the SLM-processed Al-based composites, showing a high microhardness of 214 HV0.1, a considerably low coefficient of friction (COF) of 0.39, and a reduced wear rate of 1.56 × 10−5 mm3 N−1 m−1. At an excessive laser energy input, the grain size of the in situ formed Al4SiC4 reinforcing phase, both the strip- and particle-structured Al4SiC4, increased markedly. The significant grain coarsening and the formation of the interfacial microscopic shrinkage porosity lowered the mechanical properties of the SLM-processed Al-based composites. These findings in the present work are applicable and/or transferrable to other laser-based powder processing processes, e.g., laser cladding, laser metal deposition, or laser engineered net shaping.
Preliminary Feasibility Study of Groundwater Source Geothermal Heat Pumps in Mason County and the American Bottoms Area, Illinois
Authors: Lu Xinli , Larson David R. , Holm Thomas R.
Published: October 2014

Groundwater source heat pumps exploit the difference between the ground surface temperature and the nearly constant temperature of shallow groundwater. This project characterizes two areas for geothermal heating and cooling potential, Mason County in central Illinois and the American Bottoms area in southwestern Illinois. Both areas are underlain by thick sand and gravel aquifers and groundwater is readily available. Weather data, including monthly high and low temperatures and heating and cooling degree days, were compiled for both study areas. The heating and cooling requirements for a single-family house were estimated using two independent models that use weather data as input. The groundwater flow rates needed to meet these heating and cooling requirements were calculated using typical heat pump coefficient of performance values. The groundwater in both study areas has fairly high hardness and iron concentrations and is close to saturation with calcium and iron carbonates. Using the groundwater for cooling may induce the deposition of scale containing one or both of these minerals.
A High-Flux Solar Furnace for Undergraduate Engineering Education and High-Temperature Thermochemistry Research
Authors: Duncan G. Scott , Nudehi Shahin , Palumbo Robert , Venstrom Luke J.
Published: October 2014

The optical design and engineering features of a 10 kW solar furnace now operational at Valparaiso University are described. The solar furnace is anticipated to achieve a mean concentration ratio of 3000 suns over a 6 cm diameter focus. It will support high-temperature solar chemistry research and undergraduate engineering pedagogy. Many of the components of the solar furnace were designed and constructed by undergraduate engineering students. Some of these students cite their participation in the solar furnace project as the motivating factor for continuing to work in the area of energy science in industry or graduate school.
Numerical Study of a Beam-Down Solar Thermochemical Reactor for Chemical Kinetics Analysis
Authors: Bellan Selvan , Saurez Cristina Cerpa , Gonzalez-Aguilar Jose , Romero Manuel
Published: October 2014

A lab-scale solar thermochemical reactor is designed and fabricated to study the thermal reduction of non-volatile metal oxides, which operates simultaneously as solar collector and as chemical reactor. The main purpose of this reactor is to achieve the first step in two-step thermochemical cycles. The chemical conversion rate strongly depends on the temperature and fluid flow distribution around the reactant, which are determined by the reactor geometry. The optimal design depends on the constraints of the problem and on the operating parameters. Hence, the objective of this investigation is to analyze the heat and mass transfer in the vertically-oriented chemical reactor by a CFD model and to optimize the reactor design. The developed numerical model is validated by comparing the simulation results with reported model. The influence of different technical and operating parameters on the temperature distribution and the fluid flow of the reactor are studied.
Estimation of Lighting Energy Savings From Atrium Daylighting for Office Buildings
Authors: Krarti Moncef
Published: October 2014

Atria can offer several benefits to deep plan commercial and office buildings. This includes passive heating and cooling, ventilation, and daylighting. In order to use daylight effectively in atrium buildings, the characteristics that affect the light levels and distribution must be taken into account and analyzed. These elements include roofs, shapes, well geometries, surface finishes, and glazing types. The analysis outlined in this paper shows that a larger atrium area, higher window-to-wall ratio, clear windows, and a multi-story building provide the highest energy savings. The paper also presents a simplified calculation method to determine the percent lighting energy reduction attributed to atria in office buildings with continuous dimming. The lighting energy savings due to daylighting from atria can be up to 40%.
Impacts on New York GHG Emissions From Distributed Combined Heat and Power
Authors: Howard Bianca , Waite Michael , Modi Vijay
Published: October 2014

As cities have begun to implement greenhouse gas initiatives, one technology that has become of interest is building level combined heat and power (CHP). In New York City, over two thirds of greenhouse gas emissions are attributed to buildings. As space heating is the major end use of building energy consumption in the Northeast, building level CHP systems have the potential to significantly reduce greenhouse gas emissions especially since many buildings utilize fuel oil to fire boilers for space heating.

While distributed CHP has potential to reduce energy consumption and greenhouse gas emissions, this statement is quite dependent on the current types and efficiencies of generators used to supply electricity. In New York State, approximately 50% of electricity is produced from nuclear and hydro power plants with the majority of the remainder supplied by simple and combined cycle gas turbines. Only 1% of electricity is supplied by less efficient oil power plants.

In the current work we seek to determine how the emissions benefits of distributed generation change with increasing penetration of CHP systems (up to 1.58 GW of aggregated capacity) considering the current mix of electricity generation capacity in New York State. The analysis indicates while there are emissions reductions for all scenarios the impact reduces on the order of 400 metric tons per MWe.
A General Methodology for Optimized Takagi-Sugeno Fuzzy Modeling of Nonlinear Continuous Fermenter for Biofuels (Ethanol) Production Using Golden Section Search Approach
Authors: Jacome Alfredo Diaz , Mejia Marco Sanjuan
Published: October 2014

The overcoming inclusion of biotechnology in biofuels industry involves several challenges among which are found the variety of operational cycles, the highly nonlinear behavior of the processes and the need for measurement of intermediate variables. In order to reproduce biological conversion of biodiesel production discharge products into other biofuels, experimental data from ethanol production from glycerol/glucose mixture was analyzed implementing fuzzy techniques to investigate and model the nonlinear behavior of the process. This paper presents a general methodology for TS fuzzy modeling based on a novel approach on data structured regression which consists on combination of fuzzy c-regression model and clustering using a golden search algorithm approach to adjust the proper number of membership functions to fit the model and minimize the statistic difference among the experimental data, simulated data and the Fuzzy Inference System results.
Why not an e → μ experiment? An extended exercise for students studying introductory particle physics
Authors: Conrad J. M. , Williams M. , Nienaber P.
Published: October 2014

We present an extended problem appropriate for students in a semester-long introductory elementary particle physics class. This problem requires them to synthesize concepts and investigative approaches learned throughout the class, directed toward answering the question of why muon-to-electron conversion experiments are proposed, but not electron-to-muon experiments. Although direct electron-to-muon decays are kinematically forbidden, the production of muons via the interaction of electron and photon beams is kinematically allowed, so why not propose such an experiment? In the analysis presented here, we set forth a model approach that guides students through exploration of the design of such a proposed experiment. As part of the discussion, we identify an obstacle that makes doing an experiment of this kind prohibitively difficult.
Dynamics and performance of clock pendulums
Authors: Hoyng Peter
Published: October 2014

We analyze the dynamics of a driven, damped pendulum as used in mechanical clocks. We derive equations for the amplitude and phase of the oscillation, on time scales longer than the pendulum period. The equations are first order ODEs and permit fast simulations of the joint effects of circular and escapement errors, friction, and other disturbances for long times. The equations contain two averages of the driving torque over a period, so that the results are not very sensitive to the “fine structure” of the driving. We adopt a constant-torque escapement and study the stationary pendulum rate as a function of driving torque and friction. We also study the reaction of the pendulum to a sudden change in the driving torque, and to stationary noisy driving. The equations for the amplitude and phase are shown to describe the pendulum dynamics quite well on time scales of one period and longer. Our emphasis is on a clear exposition of the physics.
Technological Innovation, Product Life Cycle and Market Power: A Real Options Approach
Authors: Cheng Johnson T. S. , Jiang I-Ming , Liu Yu-Hong
Published: October 2014

This paper employs a real options approach to analyze optimal investment decisions. When investment projects have the characteristics of irreversibility, uncertainty and the option to wait or exit, the traditional net present value (NPV) method would underestimate the value of investment, since it neglects the values of timing and operational flexibility. The distinctive feature of this paper is that the effects of product life cycle (PLC) as well as market power are incorporated into the model. In addition, and different to the approach in Liao et al. [Optimal investment decision and product life cycle: A real options approach, Sun Yat-Sen Management Review 11(3) (2003) 1–36], we introduce the concept of technological innovation into the model. It is shown that the optimal waiting time for the investment is longer than both those in the American call options model of McDonald and Siegel [The value of waiting to invest, Quarterly Journal of Economics 101(4) (1986) 707–727], which does not incorporate dividend yield, and Liao et al. [Optimal investment decision and product life cycle: A real options approach, Sun Yat-Sen Management Review 11(3) (2003) 1–36], but is shorter than that in Dixit and Pindyck's [Investment under Uncertainty (Princeton University Press, Princeton, NJ, 1994)] model, which incorporates dividend yield. Finally, a comparative static is used to analyze the determinants of optimal investment decisions. Our results indicate that the investment-ratio threshold will be higher, and thus the optimal entry time for an investment will be delayed, when (1) the PLC is longer, (2) the uncertainty is greater, (3) the discounting rate is higher, (4) market power is larger, (5) jump size intensity is stronger and (6) the payoff out ratio (R&D/revenue) is larger.