bluuebunny/crossref_metadata_2025 huggingface dataset:
Surveying Chinese In-Service K12 Teachers’ Technology, Pedagogy, and Content Knowledge
Authors: Liu Qingtang , Zhang Si , Wang Qiyun
Published: June 2015

Technology, pedagogy, and content knowledge (TPACK) has been considered as a promising theoretical framework to guide teacher educators in designing and developing in-service K12 teacher education programs. However, it seems unclear whether in-service teachers have different TPACK perceptions when entering the education programs. This study surveyed the TPACK perceptions of 2,728 Chinese in-service K12 teachers. A questionnaire adapted from Koh, Chai, and Tsai’s survey was validated by reliability and validity tests. Exploratory factor analysis revealed that Chinese in-service K12 teacher’s TPACK perceptions could be grouped into five scales. Analyses of means and standard deviation of all the variables of the TPACK construct to examine Chinese in-service K12 teachers’ TPACK perceptions showed that teachers had rated themselves as slightly above five points for all the variables. Independent sample t tests to examine the relationships between in-service K12 teachers’ gender and the TPACK variables indicated that male teachers rated themselves higher than female teachers for the variable content knowledge (CK) and lower for the variable pedagogical content knowledge. F tests to examine the relationships between in-service K12 teachers’ years of service and the TPACK variables revealed that young in-service K12 teachers tended to perceive better in the capacities of applying technology and worse in the capacities of teaching method and subject matter. Hierarchical regression analysis to explore which variables (technological knowledge, pedagogical knowledge, CK, pedagogical content knowledge, technological content knowledge, and technological pedagogical knowledge) could predict the variable of TPACK showed that in-service K12 teachers’ perceptions of pedagogical knowledge, technological knowledge, and CK had the largest positive effect on the TPACK variable.
Korean Media Often Allied with Ruling Political Parties
Authors: Park Chang Sup
Published: June 2015

A framing analysis of South Korea’s three major newspapers and two television networks reveals that coverage of presidential election polls was heavily biased toward the ruling party and its candidate. The Korean mainstream media stories more often focused on the race between candidates than on political issues of the campaign.
Dynamics and efficiency of planetary gear sets for hybrid powertrains
Authors: Mohammadpour M , Theodossiades S , Rahnejat H
Published: June 2015

The paper presents a tribo-dynamic model for planetary gear sets of hybrid-electric-vehicle configurations. The model comprises a six degree-of-freedom torsional multi-body dynamic system, as well as a tribological contact model in order to evaluate the lubricant film thickness, friction and efficiency of the meshing gear teeth contacts. The tribological model takes into account the non-Newtonian, thermal-mixed elastohydrodynamic regime of lubrication. Analysis is performed for a hybrid electric C-segment vehicle. The simulated conditions correspond to cases of power supplied by either the engine or the electric motor. The results illustrate that in the electric motor drive mode, improved noise, vibration and harshness refinement would be expected, whereas better transmission efficiency is achieved in the internal combustion engine drive mode.
Capitalist normativity: Value and values
Authors: Weiss Hadas
Published: June 2015

In this paper I locate values within a uniquely capitalist confrontation between freedom and nonagency. Freedom marks individual’s freedom to buy and sell work and commodities according to their own capacities and preferences. Nonagency marks their dependence on market exchange for the goods and services they need, and lack of control over their production. I call this confrontation between freedom and nonagency value, and I consider this the social relation that defines the capitalist mode of production. People partaking in this relation who nevertheless exert a measure of influence over their immediate surroundings often use their influence to try and reconcile their freedom with their nonagency. I argue here that values are their means of doing so, because values extend freedom to meet necessity on more morally palatable terms. Values are therefore most prevalent among middle classes and under welfare regimes, where the requisite influence is provided. In the absence of such influence, mediation between freedom and nonagency is no longer possible. Values then give way to different forms of normativity such as pragmatism, duty, or virtue, all of which are presently gaining ground.
Investigation of wear and tool life of coated carbide and cubic boron nitride cutting tools in high speed milling
Authors: Twardowski Pawel , Legutko Stanislaw , Krolczyk Grzegorz M , Hloch Sergej
Published: June 2015

The objective of the investigation was analysis of the wear of milling cutters made of sintered carbide and of boron nitride. The article presents the life period of the cutting edges and describes industrial conditions of the applicability of tools made of the materials under investigation. Tests have been performed on modern toroidal and ball-end mill cutters. The study has been performed within a production facility in the technology of high speed machining of 55NiCrMoV6 and X153CrMoV12 hardened steel. The analysed cutting speed is a parameter which significantly influences the intensity of heat generated in the cutting zone. Due to the wear characteristics, two areas of applicability of the analysed tools have been distinguished. For vc ≤ 300 m/min, sintered carbide edges are recommended; for vc > 500 m/min, boron nitride edges. For 300 ≤  vc ≤ 500 m/min, a transition area has been observed. It has been proved that the application of sintered carbide edges is not economically justified above certain cutting speed.
Modeling on thermally induced coupled micro-motions of satellite with complex flexible appendages
Authors: Zhou Zhicheng , Liu Zhengshan , Qu Guangji
Published: June 2015

To describe the characteristics of thermally induced coupled micro-motions more exactly, a numerical model is proposed for a satellite system consisting of a rigid body and the complex appendages. The coupled governing equations including the effects of transient temperature differences are formulated within the framework of the Lagrangian Method based on the finite element models of flexible structures. Meanwhile, the problem of coupling between attitude motions of rigid body and vibrations of flexible attachments are addressed with explicit expressions. Thermally induced micro-motions are examined in detail for a simple satellite with a large solar panel under the disturbance of thermal environment from earth shadow to sunlight area in the earth orbit. The results show that the thermal–mechanical performances of an on-orbit satellite can be well predicted by the proposed finite element model.
Networks of digital humanities scholars: The informational and social uses and gratifications of Twitter
Authors: Quan-Haase Anabel , Martin Kim , McCay-Peet Lori
Published: June 2015

Big Data research is currently split on whether and to what extent Twitter can be characterized as an informational or social network. We contribute to this line of inquiry through an investigation of digital humanities (DH) scholars’ uses and gratifications of Twitter. We conducted a thematic analysis of 25 semi-structured interview transcripts to learn about these scholars’ professional use of Twitter. Our findings show that Twitter is considered a critical tool for informal communication within DH invisible colleges, functioning at varying levels as both an information network (learning to ‘Twitter’ and maintaining awareness) and a social network (imagining audiences and engaging other digital humanists). We find that Twitter follow relationships reflect common academic interests and are closely tied to scholars’ pre-existing social ties and conference or event co-attendance. The concept of the invisible college continues to be relevant but requires revisiting. The invisible college formed on Twitter is messy, consisting of overlapping social contexts (professional, personal and public), scholars with different habits of engagement, and both formal and informal ties. Our research illustrates the value of using multiple methods to explore the complex questions arising from Big Data studies and points toward future research that could implement Big Data techniques on a small scale, focusing on sub-topics or emerging fields, to expose the nature of scholars’ invisible colleges made visible on Twitter.
Rapid Training and Implementation of the Pollock Technique, a Safe, Effective Newborn Circumcision Procedure, in a Low-Resource Setting
Authors: Kojima Noah , Bristow Claire C. , Pollock Neil , Crouse Pierre , Theodore Harry , Bonhomme Jerry , Gaston Claire F. Stéphanie , Dévieux Jessy G. , Pape Jean William , Klausner Jeffrey D.
Published: June 2015

Male circumcision is highly protective against urinary tract infections, inflammatory conditions of the penis, sexually transmitted infections, and urogenital cancers. We aimed to reintroduce newborn male circumcision through the creation of a training program in Port-au-Prince, Haiti—an area with a considerable burden of preventable urogenital infections, sexually transmitted infections, and low circumcision rate—after an earlier study reported that a majority of Haitian medical providers were in need of and wanted newborn circumcision training. The program was conducted at the GHESKIO Health Centers, a large, non-governmental clinic offering comprehensive pediatric and adult health services. Two Haitian obstetricians and seven nurses learned circumcision procedures. On training completion, one of two obstetricians achieved surgical competence. Introduction of a newborn male circumcision training program was feasible, achieving an acceptable rate of procedural competency and high-quality services. Permanent resources now exist in Haiti to train additional providers to perform newborn male circumcisions.
A drive through cellular therapy for CLL in 2015: allogeneic cell transplantation and CARs
Authors: Mato Anthony , Porter David L.
Published: June 2015

Over the past decade the development of safer reduced-intensity conditioning regimens, expanded donor pools, advances in supportive care, and prevention/management of graft-versus-host disease have expanded stem cell transplantation (SCT) availability for chronic lymphocytic leukemia (CLL) patients. However, there are now increasingly active treatment options available for CLL patients with favorable toxicity profiles and convenient administration schedules. This raises the critical issue of whether or not attainment of cure remains a necessary goal. It is now less clear that treatment with curative intention and with significant toxicity is required for long-term survival in CLL. In addition, the demonstrated safety and activity of genetically modified chimeric antigen receptor (CAR) T cells present the opportunity of harnessing the power of the immune system to kill CLL cells without the need for SCT. We attempt to define the role of SCT in the era of targeted therapies and discuss questions that remain to be answered. Furthermore, we highlight the potential for exciting new cellular therapy using genetically modified anti-CD19 CAR T cells and discuss its potential to alter treatment paradigms for CLL.
Recurrent CDKN1B (p27) mutations in hairy cell leukemia
Authors: Dietrich Sascha , Hüllein Jennifer , Lee Stanley Chun-Wei , Hutter Barbara , Gonzalez David , Jayne Sandrine , Dyer Martin J. S. , Oleś Małgorzata , Else Monica , Liu Xiyang , Słabicki Mikołaj , Wu Bian , Troussard Xavier , Dürig Jan , Andrulis Mindaugas , Dearden Claire , von Kalle Christof , Granzow Martin , Jauch Anna , Fröhling Stefan , Huber Wolfgang , Meggendorfer Manja , Haferlach Torsten , Ho Anthony D. , Richter Daniela , Brors Benedikt , Glimm Hanno , Matutes Estella , Abdel Wahab Omar , Zenz Thorsten
Published: June 2015

Key Points

Somatic CDKN1B (p27) mutations were identified in 16% (13/81) of HCL patients and coexist with BRAFV600E mutations. CDKN1B is the second most common mutated gene in HCL implicating altered cell cycle regulation and/or senescence in HCL.
CdSe/ZnS Quantum Dots-Labeled Mesenchymal Stem Cells for Targeted Fluorescence Imaging of Pancreas Tissues and Therapy of Type 1 Diabetic Rats
Authors: Liu Haoqi , Tang Wei , Li Chao , Lv Pinlei , Wang Zheng , Liu Yanlei , Zhang Cunlei , Bao Yi , Chen Haiyan , Meng Xiangying , Song Yan , Xia Xiaoling , Pan Fei , Cui Daxiang , Shi Yongquan
Published: June 2015

Mesenchymal stem cells (MSCs) have been used for therapy of type 1 diabetes mellitus. However, the in vivo distribution and therapeutic effects of transplanted MSCs are not clarified well. Herein, we reported that CdSe/ZnS quantum dots-labeled MSCs were prepared for targeted fluorescence imaging and therapy of pancreas tissues in rat models with type 1 diabetes. CdSe/ZnS quantum dots were synthesized, their biocompatibility was evaluated, and then, the appropriate concentration of quantum dots was selected to label MSCs. CdSe/ZnS quantum dots-labeled MSCs were injected into mouse models with type 1 diabetes via tail vessel and then were observed by using the Bruker In-Vivo F PRO system, and the blood glucose levels were monitored for 8 weeks. Results showed that prepared CdSe/ZnS quantum dots owned good biocompatibility. Significant differences existed in distribution of quantum dots-labeled MSCs between normal control rats and diabetic rats (p < 0.05). The ratios of the fluorescence intensity (RFI) analysis showed an accumulation rate of MSCs in the pancreas of rats in the diabetes group, and was about 32 %, while that in the normal control group rats was about 18 %. The blood glucose levels were also monitored for 8 weeks after quantum dots-labeled MSC injection. Statistical differences existed between the blood glucose levels of the diabetic rat control group and MSC-injected diabetic rat group (p < 0.01), and the MSC-injected diabetic rat group displayed lower blood glucose levels. In conclusion, CdSe/ZnS-labeled MSCs can target in vivo pancreas tissues in diabetic rats, and significantly reduce the blood glucose levels in diabetic rats, and own potential application in therapy of diabetic patients in the near future.
A positive fluid balance is an independent prognostic factor in patients with sepsis
Authors: Acheampong Angela , Vincent Jean-Louis
Published: June 2015

Introduction

Intravenous fluid administration is an essential component of sepsis management, but a positive fluid balance has been associated with worse prognosis. We analyzed whether a positive fluid balance and its persistence over time was an independent prognostic factor in septic patients.

Methods

We prospectively studied fluid intake and output for 7 days in 173 consecutive adult patients treated for sepsis in our Department of Intensive Care.

Results

Of the 173 patients, 59 died (34 %). Mean daily fluid intake was higher in non-survivors than in survivors (59 ± 24 ml/kg vs. 48 ± 23 ml/kg, p = 0.03), but output volumes were similar. As a result, the daily fluid balance was more than twice as large in the non-survivors as in the survivors (29 ± 22 vs. 13 ± 19 ml/kg, p <0.001). Persistence of a positive fluid balance over time was associated with increased mortality. Using a multivariable time-dependent Cox model, a positive fluid balance was independently associated with higher mortality (adjusted hazard ratio 1.014 [1.007–1.022] per ml/kg increase, p <0.001).

Conclusions

Persistence of a positive daily fluid balance over time was quite strongly associated with a higher mortality rate in septic patients.
Obtaining Enhanced Photocurrent by Beneficial Surface Treatment of Self-aligned TiO2 Nanotubes for Dye-sensitized Solar Cells
Authors: Kwak Su Hyeon , Kang Soon Hyung
Published: June 2015

Electrochemically anodic TiO2 nanotube (TONT) arrays were prepared in ethylene glycol solvent containing 0.25 wt % NH4F and 2 wt % water under constant voltage (60 V) for 1 h. As-grown TONT arrays exhibited an amorphous phase, and thermal treatment was performed at 450 °C for 3 h under air gas to improve the crystallinity. In addition, to develop water-treated TONT arrays, as-grown TONT arrays were directly placed in water for 3 days. After removing the sample from water, thermal treatment was performed under the same conditions. Further, to prepare the TiCl4-treated TONT arrays (denoted as TiCl4/TONT), the annealed TONT arrays were placed in 0.02 M TiCl4 aqueous solution in a 70 °C electric oven for 30 min. Three types of TONT arrays were prepared and characterized: TONT, TiCl4/TONT, and water/TONT. In the case of TiCl4/TONT arrays, the TiCl4 treatment has a well-known ability to create TiO2 nanoparticles on the TiO2 surface, increasing the surface area for dye uptake and beneficial charge-transport properties. Here, the TiCl4/TONT arrays showed high photocurrent due to the high dye uptake, resulting in 18% improvement of photoelectric conversion efficiency (η). Meanwhile, water/TONT arrays provide the largest surface area due to the small nanoparticles composed of the surface in the nanotubular structure. The beneficial electron-transport properties of water/TONT system through c axis led to an enhancement of up to 40%, approaching η of 2.65%, compared to 1.87% for TONT-based dye-sensitized solar cells.
Graphene Wet-etching Kinetics as Time-reversed Crystallization
Authors: Watanabe Yu-uto , Ikemura Yu-usuke , Sano Masahito
Published: June 2015

Wet-etching kinetics of single-layer graphene and multilayer graphene oxide by piranha solution under a mild condition was modeled as a time-reversed crystallization process and was analyzed by Avrami theory. The Avrami exponent is 1 at the early stage of the reaction for both materials, indicating that etching proceeds along reactive edges without forming additional defects. Then, the exponent for graphene changes to 2 whereas that of graphene oxide increases to 4. Stretched exponential behavior is also observed for highly defective samples.
First Total Synthesis of Neoantimycin
Authors: Ogawa Hikaru , Iio Hideo , Usuki Yoshinosuke
Published: June 2015

The first total synthesis of neoantimycin (1), an unusual ring-extended antibiotic of the antimycin class, has been achieved, using intramolecular transesterification for construction of the 15-membered tetralactone core.
Racial Realism: A Review Essay on John Skrentny's After Civil Rights
Authors: Lang Kevin
Published: June 2015

In his valuable contribution, After Civil Rights, John Skrentny shows that in many sectors of the labor market, race is used in ways that were unanticipated when the 1964 Civil Rights Act was enacted. With separate chapters on the professions and business, the public sector, media and entertainment, and the low-skill market, he demonstrates that the new racial realism is widespread, generally has some justification from social scientific research, and is usually inconsistent with judicial decisions. I review the racially realistic practices (racial matching, increasing diversity, racial signaling, and racial characteristics) and discuss their implications for labor economics and for policy. (JEL J15, J24, J71, J81, K31)
Distribution and Enrichment Mode of Li in the No. 11 Coal Seam from Pingshuo Mining District, Shanxi Province
Authors: Wang Jinxi , Wang Qi , Shi Jie , Li Zhongsheng
Published: June 2015

One hundred and fifteen bench-coal samples were taken from the No. 11 Coal Seam of the Carboniferous in Pingshuo Mining District. These samples were analyzed by ICP-MS, X-ray powder diffraction, SEM–EDX methods. The results indicate that the average Li content reaches 368.84 mg/kg. It is as much as 30 times higher than that of the world coals and 11 times higher than that of Chinese coals. The calculated total Li reserves reach to 259 kt, that is equivalent to, 56 kt Li2O in the No. 11 coal seam in the Pingshuo Mining District. The minerals in the coals are mainly clay, pyrite, and a minor amount of oxide and other minerals. The lithium tends to occur in clay minerals and mainly associated with inertinite maceral. The majority of Li in the No. 11 coal might have migrated from the underlying Yinshan Oldland or bauxite of the Benxi formation by absorption mechanism. The bauxite of the Benxi formation may be the most possible source of Li in the coal from the Pingshuo District.
How the Energy Sector Could Get it Wrong with Cloud Computing
Authors: Perrons Robert K.
Published: June 2015

Cloud computing has significantly impacted a broad range of industries, but these technologies and services have been absorbed throughout the marketplace unevenly. Some industries have moved aggressively towards cloud computing, while others have moved much more slowly. For the most part, the energy sector has approached cloud computing in a measured and cautious way, with progress often in the form of private cloud solutions rather than public ones, or hybridized information technology systems that combine cloud and existing non-cloud architectures. By moving towards cloud computing in a very slow and tentative way, however, the energy industry may prevent itself from reaping the full benefit that a more complete migration to the public cloud has brought about in several other industries. This short communication is accordingly intended to offer a high-level overview of cloud computing, and to put forward the argument that the energy sector should make a more complete migration to the public cloud in order to unlock the major system-wide efficiencies that cloud computing can provide. Also, assets within the energy sector should be designed with as much modularity and flexibility as possible so that they are not locked out of cloud-friendly options in the future.
Desired Dynamic Equation Based PID Control for Combustion Vibration
Authors: Makeximu  , Li Donghai , Zhu Min , Sun Li
Published: June 2015

Lean Premixed Pre-vaporized technology aiming at reducing nitrogen oxide emission has an inherent drawback of causing combustion instability. Model-based active controller design to suppress the unstable combustion needs the open-loop transfer function of the object which is difficult to acquire and often with inaccuracies in many ways. Desired dynamic equation based PID (DDE-PID) is a model free control strategy which requires little knowledge of the object process, and also has the advantage of limited number of parameter variables to be tuned and simplicity of tuning method. A certain DDE-PID controller is designed and a set of parameter tuning method is given and tested on a open loop transfer function obtained from real experimental data fitting. With nonlinear features like input amplitude limiting and output limiting to resemble the actual system, the simulation results are compared with two model based control strategies which has been tested in actual system and proved to be feasible. The result shows DDE-PID could achieve similar control effect with structural simplicity and tuning easiness.
Numerical Analysis of Thermoacoustic Characteristics of Components inside a Complex Aircraft Related to the Coupling Effect of High Temperature and Random Vibration
Authors: Bai Yu-Guang , Zhao Yan , Xia Guang-Qing , Zhang You-Wei , Kennedy David , Williams Fred
Published: June 2015

Hypersonic aircraft always face bad flight environment related to the coupling effects of high temperature and random vibration. Numerical analysis of thermoacoustic characteristics of components inside such an aircraft is presented in this paper. An actual aircraft cabin composite structure including a heat resistant layer, an adiabatic layer and metal frameworks is modeled with the finite element mesh generation method. Transient heat conduction of the hypersonic flight aircraft is analyzed based on a block-iterative coupling method which can consider the atmosphere-aircraft interaction. Then the Von Karman turbulence spectrum is employed to define the random vibration environment of the present aircraft. The thermodynamic response of the system is solved by the pseudo-excitation method which can improve the computation efficiency greatly. Finally, thermoacoustic characteristic of the cavity inside the aircraft cabin is analyzed when the transient heat conduction and random vibration due to atmosphere turbulence are both included. A numerical method is proposed based on a structure-acoustic coupling method which can use acoustic equations to simulate the propagation of the acoustic wave in the flow. It can be found from the computed results that the change of the temperature influences both the thermodynamic characteristic of the aircraft cabin and thermoacoustic characteristic of the component inside the present aircraft significantly. So the coupling effects of high temperature and random vibration on thermoacoustic characteristic of a hypersonic flight aircraft cannot be neglected. The proposed numerical analysis method in this paper can be widely applied to numerical investigations of thermoacoustic systems inside hypersonic aircraft.
Low Frequency Beating Instability in a Rijke Burner and its Active Control
Authors: Weng Fanglong , Makeximu  , Li Donghai , Zhu Min
Published: June 2015

A special pattern of thermoacoustic oscillation has been observed in a Rijke burner. The acoustic pressure histories show obvious amplitude modulation at very low frequencies, namely beating instability. Accompanied with the amplitude modulation, the porous-plug stabilized flame also shows low frequency pulsations. This beating can be caused by the interaction of flame dynamics at different time scales. Accordingly, dynamic models of a ceramics stabilized flat flame are developed at two distinctive time scales and embedded in an acoustic network system. Simulation results show that low frequency flame temperature pulsation can lead to obvious amplitude modulation. Furthermore, aiming to suppress the beating instability with active control, the effects of amplitude modulation on thermoacoustic oscillation control have been studied. A phase shift controller and a phase lag compensator are tested, and the simulation results illustrate the challenge that may be encountered in the control of beating instabilities.
Experimental Investigation of Feedback Control of Thermoacoustic Oscillations Using Least Mean Square-Based Algorithms
Authors: Zhang Zhiguo , Guan Di
Published: June 2015

Thermoacoustic instabilities are characterized by self-sustained large-amplitude pressure oscillations, which are produced by the interaction between unsteady heat release and acoustic waves. Such instabilities are detrimental to land-based gas turbine and aero-engines. To mitigate thermoacoustic instabilities, the coupling between unsteady heat release and pressure perturbations must somehow be interrupted. Feedback control techniques with a dynamic controller implemented can be used to achieve this. One of the most classical controllers is based on a finite- or infinite-impulse response filter, whose coefficients are optimized using least mean square algorithm (LMS). In this work we experimentally investigated and compared the performance of four LMS-based algorithms on stabilizing an unstable thermoacoustic system. Effects of the step size and filter length are studied one at a time. It is found that the filter length plays an important role in determining the convergence speed and steady error. In addition, the step size involved in the LMS algorithms is shown to be varied over a wide range. However, when the step size is small, simplified/revised LMS-based algorithms perform better than the conventional one in the absence of a feedback term. However, with the step size increased, these algorithms behave similarly. In order to improve the performance of conventional LMS-based algorithms, a time-varying step-size controller is developed and experimentally implemented. Approximately 50 dB sound reduction is achieved. The controller is also demonstrated to be able to track and prevent the onset of new limit cycle resulting from the changes of fuel flow rate. Finally, the transfer function of the thermoacoustic system is measured by injecting broad-band white noise.
Observer-Based Sliding Mode Control of Rijke-Type Combustion Instability
Authors: Rubio-Hervas Jaime , Reyhanoglu Mahmut , MacKunis William
Published: June 2015

Observer-based sliding mode control of combustion instability in a Rijke-type thermoacoustic system is considered. A commonly used thermoacoustic model with sensors and monopole-like actuators is linearized and formulated in a state-space form. It is assumed that the velocity or pressure sensor locations are chosen to assure the observability of the system. An observer-based sliding mode controller is then implemented to tune the actuators so that the system is asymptotically stable. The effectiveness of the controller is illustrated through a simulation example involving two modes and one sensor. The successful demonstration indicates that the observer-based feedback controller can be applied to a real combustion system with multiple modes.
Methane Adsorption Microcalorimetry of Activated Carbon Fibre Synthesized from Empty Fruit Bunch Fibre
Authors: Lee Ting , Tan Wan-Cheng , Matsumoto Akihiko , Yeoh Fei-Yee
Published: June 2015

In this article, the methane adsorption behaviour of activated carbon fibre (ACF), a nanoporous material, was examined for adsorbed natural gas (ANG) applications. The ACF was produced from palm fibre-based materials through carbonization, followed by CO2 activation. The carbonization of empty fruit bunch (EFB) fibres was conducted at temperatures of 85–250 °C in an oxidative atmosphere. The produced ACF showed well-developed pore structure with high micropore volume and excellent pore-size distribution. The ACF, predominantly with microporous pores, fulfils the requirements as an excellent adsorbent for methane adsorption. The optimal carbonization conditions for improving methane adsorption capacity were achieved using concentrated H2SO4 at 250 °C, followed by activation at 900 °C. Only physisorption occurred during the adsorption of methane on ACF. The EFB fibre-derived ACF has high potential for use in NG adsorption and storage applications via ANG technology.
Competitive Adsorption of Carbon Monoxide and Water Vapour on MIL-100(Fe) Prepared Using a Microwave Method
Authors: Wang Sha , Li Xuemei , Zhao Zhenxia , Li Zhong
Published: June 2015

Competitive adsorption of CO and water vapour on MIL-100(Fe) synthesized using a microwave method was systematically investigated. Adsorption equilibrium, kinetics of CO adsorption and the competitive adsorption of CO/H2O(V) within MIL-100(Fe) were evaluated. Results show that the unsaturated Fe(II) can enhance the adsorption amount of CO on MIL-100(Fe). The adsorbed amount of CO on MIL-100(Fe) was 2.56 mmol/g at 298 K and 10 bar with isosteric adsorption heat of 28.31–38.43 kJ/mol. MIL-100(Fe) had two kinds of adsorption sites with desorption activation energy of 53.38 and 109.5 kJ/mol for CO, respectively. The diffusion coefficient of CO through MIL-100(Fe) was approximately 2.85 times higher than that of water vapour (10.54 × 10−16 cm2/s vs. 2.735 × 10−16 cm2/s). The working adsorption amount of CO at 40% relative humidity was approximately 0.631 mmol/g, retaining 75% of the original adsorption amount, indicating that CO is more competitive than H2O on the surface of MIL-100(Fe) under humid conditions.
An Overview of Historical and Contemporary Concrete Shells, Their Construction and Factors in Their General Disappearance
Authors: Tang Gabriel
Published: June 2015

Only through understanding why concrete shells' loss in popularity over the course of modern history can designers be equipped with the skills to create and apply this type of construction. Through modifications to design processes, construction stages, material understanding and relevant formwork improvements will architects and designers be able to meet the demands of the 21st century and beyond.

To understand why concrete shells are no longer commonly built is to understand its construction process. An amorphous material, the fundamental relationship between formwork and the resultant concrete shell needs to be raised, appreciated, understood and analyzed for a holistic understanding of concrete shells. Through understanding this, issues and factors affecting concrete shells can be tackled and designed out in reviving this type of structures because they can be efficient in structural performance, economical in cost and provide high aesthetic value.

This paper discusses concrete shells as an architectural solution by asking the question to what constituted their popularity and factors that led to their demise in the modern age of technological advancement, construction process and environmental concerns. This paper presents a cultural perspective and an overview of seminal, historical and contemporary concrete shells so as to bring about a renaissance of such structures in our built environment once again because of all the benefits it can offer.
Stability of Pseudo-Funicular Elastic Grid Shells
Authors: Mesnil Romain , Ochsendorf John , Douthe Cyril
Published: June 2015

The paper presents some results on the influence of the pre-stress induced by the erection method of elastic grid shells on their buckling capacity. It starts with the numerical methods and their validation with the study of a prebuckled arch. Then, a form-finding scheme using low-speed dynamics is used to generate automatically a family of elastic grid shells, and their buckling capacity is compared to the one of grid shells with the exact same geometry, but without any pre-stress. The paper demonstrates finally that the pre-stress decreases by a few percent the buckling capacity of elastic grid shells.
Micro-Siting of Wind Turbine in Complex Terrain: Simplified Fatigue Life Prediction of Main Bearing in Direct Drive Wind Turbines
Authors: Watanabe Fumihito , Uchida Takanori
Published: June 2015

In Japan, 1,516 wind turbine accidents have been recorded between year 2004 and 2012, and 84% of them were for turbines in complex terrains. The longest downtime was associated with damage to main shafts or bearings with an average downtime of 5.7 months. Careful micro-siting in complex terrains can prevent these accidents from happening.

The objective of the paper is to provide an intermediate step that allows consultants, developers, and wind farm owners to further evaluate micro-siting of wind turbines in complex terrains, prior to load simulations by manufacturers. The author developed a simplified method to predict fatigue life of a main rear bearing in direct drive wind turbines. The method uses hub-height 10 minutes wind data as an input. The validation with an actual accident showed practically good agreement of 12.0 years of the predicted life against 12.7 years of the actual life. The method was also applied to quantify the effect of a curtailment. The proposed curtailment increased the predicted life to 35.5 years with a relatively small range of wind speed at a direction of only 1 % frequency distribution.

With the proposed method, it is possible to layout turbines where fatigue life of a main rear bearing is longer than its design life. The method can also be applied to existing turbines in order to spot turbines that require careful maintenance, and to consider an installation of condition monitoring system on a bearing.
Novel Ozonation Technique to Delignify Wheat Straw for Biofuel Production
Authors: Baig K. S. , Wu J. , Turcotte G. , Doan H.D.
Published: June 2015

Production of ethanol from lignocellulosic biomass is a promising alternative source of energy because this world is in need of a low cost, renewable and sustainable green energy source. Canada is among the top ten producers of wheat in the world with a capability of producing around 37.52 million tons of wheat straw per year. Hence, wheat straw could be a potential source of energy. Ozone was supposed to break down physical and chemical structure of lignin and hence make cellulose present in wheat straw more accessible for a conversion reaction. However, it was observed in our experimental work that without pretreatment of wheat straw, ozone did not produce the expected effects in the reaction with wheat straw. In spite of conducting the experiments under vigorous conditions only 13 % of lignin removal was achieved. The proposed technique, which is a strategic use of water and ozone, has overcome the problem of slow reaction of ozone with wheat straw. Through this technique, around 90% acid insoluble lignin (AIL) removal was achieved by controlling parameters such as reaction time, flow rate of ozone-oxygen feed stream, ozone concentration in ozone-oxygen feed stream, water contents and particle size. The maximum AIL (90%) was obtained at flow rates of 4L/min, 2L/min and 1L/min at reaction times 90, 120 and 180 minutes, respectively, with 2% wt ozone concentration in ozone-oxygen stream. Other factors supported maximum lignin removal were water contents at 3 times of the dry weight of wheat straw and at 0.5 mm particle size of wheat straw. It was also noted that excessive ozonation caused repolymerization of lignin by-products. The obtained results demonstrated that ozonation of wheat straw using the proposed technique was practical, easy to manage for the removal of lignin and it may be considered as an alternative method for delignification of biomass in production of biofuel.
Public Acceptance of Electricity Generation Sources: The Role of Trust in Regulatory Institutions
Authors: Bronfman Nicolas C. , Jiménez Raquel B. , Arevalo Pilar C. , Cifuentes Luis A.
Published: June 2015

The aim of this study was to characterize the influence that different dimensions of public trust in regulatory institutions have on social acceptability judgments of electricity generation sources in Chile. Chilean university students' acceptability judgments of ten energy sources were characterized using a web-based survey, covering risk and benefit perceptions, declared levels of acceptability, and trust in regulatory institutions. Our results confirm the influence of public trust in regulatory institutions on general perceptions and acceptance of electricity generation sources, and corroborate the presence of two dimensions of trust in regulatory institutions: integrity-based trust and competence-based trust. Our results revealed a significant influence of both aspects on risk and benefit perceptions and acceptance of fossil fuels, biomass and nuclear power, while for NRES no significant relationships were found. For hydropower, integrity-based trust was the only form of trust that influenced perceptions of risks and benefits, and its influence over public acceptance was significantly larger than competence-based trust. Further analyses of results for each energy source and implications for regulators are discussed.
Negligence, Non-Science, and Consensus Climatology
Authors: Frank Patrick
Published: June 2015

The purported consensus that human greenhouse gas emissions have causally dominated the recent climate warming depends decisively upon three lines of evidence: climate model projections, reconstructed paleo-temperatures, and the instrumental surface air temperature record. However, CMIP5 climate model simulations of global cloud fraction reveal theory-bias error. Propagation of this cloud forcing error uncovers a r.s.s.e. uncertainty 1σ ≈ ±15 C in centennially projected air temperature. Causal attribution of warming is therefore impossible. Climate models also fail to reproduce targeted climate observables. For their part, consensus paleo-temperature reconstructions deploy an improper ‘correlation = causation’ logic, suborn physical theory, and represent a descent into pseudo-science. Finally, the published global averaged surface air temperature record completely neglects systematic instrumental error. The average annual systematic measurement uncertainty, 1σ = ±0.5 C, completely vitiates centennial climate warming at the 95% confidence interval. The entire consensus position fails critical examination and evidences pervasive analytical negligence.
An Estimate of the Centennial Variability of Global Temperatures
Authors: Lloyd Philip J.
Published: June 2015

There has been widespread investigation of the drivers of changes in global temperatures. However, there has been remarkably little consideration of the magnitude of the changes to be expected over a period of a few decades or even a century. To address this question, the Holocene records up to 8000 years before present, from several ice cores were examined. The differences in temperatures between all records which are approximately a century apart were determined, after any trends in the data had been removed. The differences were close to normally distributed. The average standard deviation of temperature was 0.98 ± 0.27 oC. This suggests that while some portion of the temperature change observed in the 20th century was probably caused by greenhouse gases, there is a strong likelihood that the major portion was due to natural variations.
Carbon Dioxide Flux Measurements Based on Satellite Observations Differ Considerably from the Consensus Values
Authors: Parker A. , Ollier C.D.
Published: June 2015

The Greenhouse Gases Observing Satellite (GOSAT) satellite provides the first measured CO2 flux data that can be used to determine if a region is sequestering or emitting CO2. Results differ considerably from the popular accepted view. In the specific case of Australia, the observational data show this country is a top sequestering and not a top emitting country.
Acoustic Quality of a Tensile Membrane Structure Used as a Lecture Hall, and Proposals for its Improvement
Authors: Nocera Francesco , Gagliano Antonio , Evola Gianpiero , Gioia Mirko Cascio
Published: June 2015

Tensile membrane structures can offer considerable weight saving, becoming attractive for designers in several technological areas. They also have the advantage of realizing an enormous space without columns and beams. Furthermore, they can produce a unique atmosphere as well as savings on electricity for interior lighting, due to their light transmission properties. Unfortunately, membrane structures have serious defects in sound-insulation performance, rain-noise problems and low thermal insulation. Consequently, it is not easy to ensure acoustic comfort inside tensile membrane structures, because the techniques that normally apply to traditional buildings are not suitable in lightweight structures. For these reasons, this paper investigates the acoustic behaviour of a tensile membrane structure used as a lecture room, through instrumental techniques and simulation with software for room acoustics, in order to propose possible solutions applicable to similar structures.
A Probabilistic Model for the Flexural Capacity of Reinforced Concrete Structures Strengthened with Prestressed CFRP Plates
Authors: Liu Yang , Peng Hui , Cai C.S.
Published: June 2015

Strengthening concrete structures with prestressed carbon fiber reinforced polymer (CFRP) materials has gained popularity in recent years due to its ability to efficiently utilize the material's strength. However, the reliability of structures strengthened with prestressed CFRP laminates is a key issue. In this paper the statistical characteristics of design variables of reinforced concrete beams strengthened with prestressed CFRP plates are assessed. Accounting for the gradient effects, the Weibull distribution is used to describe the probability distribution function of the size and stress. The loss of prestressing force is analyzed considering the prestressing method. The probabilistic models of the flexural capacity are established for the three failure models, and the influence of variables on the flexural capacity is also studied. The probabilistic model derived in this paper can be used as the theoretical basis of reliability analysis and safety assessment of structures strengthened with CFRP materials.
Earthquake Damage Evaluation of T-Shaped SRC Composite Column-Steel Beams in 3D Connection Joints
Authors: Xu J.J. , Chen Z.P. , Chen Y.L. , Xue J.Y.
Published: June 2015

This paper focuses on the study of seismic-induced damage assessment of three-dimensional (3D) joints connected with T-shaped steel reinforced concrete (SRC) column-steel beams. Low cyclic reversed loading tests on one planar joint and nine 3D joints were firstly conducted to intensively investigate the seismic behavior of the hybrid joint. The damage index calculation models such as the displacement-based type, energy-based type and displacement & energy-based type were discussed and applied for all the specimens according to the experimental results. In addition, the effects of shape steel configuration type, loading angle and axial compression ratio on the damage development and accumulation for test specimens were analyzed through Park-Ang model. The analysis results show that the selected parameters of damage-index calculation models have great effect on the developing trends of damage curves. Under the same ability of relative deformation, the accumulated damage of the specimens configured with T-shaped steel are much larger than that of the specimens configured with channel-shaped and solid-web steels; moreover, the degree of damage accumulation for the specimens under 30° and 60° loading angles is slightly larger than that of the specimens under 45° loading angle. The specimens subjected to a lower axial force level have a faster damage development, but the damage accumulation is smaller than that of the specimens under a higher axial compression ratio.
Elasto-Plastic Seismic Response of RC Continuous Bridge with Foundation-Pier Dynamic Interaction
Authors: Zheng Yue , Chen Bo , Chen Weizhen
Published: June 2015

In civil engineering projects, shallow foundation is often employed as a base for bridges, wind-turbines, oil tanks and so on. But shallow foundation experiences obvious uplift and plastic deformation under intensive earthquake action. Existing solution to the problem relies on the study of soil-structure interaction (SSI) aiming at the nonlinear performance of soil foundation rather than at a coupled bridge-foundation system. To save the situation, this paper presents a two-degree of freedom (2DOF) model, considering nonlinearities of both RC pier and soil foundation, to evaluate seismic responses of a bridge-foundation system. The 2DOF model provides equations of motion to calculate constant damping effect and the time-varying damping effect, respectively. In addition, the revised Winkler foundation model, considering nonlinear bending moment versus rotation, is used to study plasticity and uplift effects of soil foundation, the modified Takeda hysteretic model is employed to simulate the nonlinear performance of RC bridge piers, and the numerical simulation of a typical RC continuous bridge with shallow foundation in four ground motions and incremental seismic intensities is conducted to assess the seismic performance of the bridge-foundation system. According to the results from these studies, the 2DOF model, truly reflecting the nonlinear properties of both RC pier and soil foundation, is proved more reasonable than the existing SDOF model for overestimating the seismic response of the bridge-foundation system. Moreover, the ratio of the moment resist stiffnesses of the RC pier and the soil-foundation is a critical factor affecting the seismic behavior and the time-varying damping, favorable in dissipating earthquake energy but unfavorable in limiting the displacement response at top of the pier.