bluuebunny/crossref_metadata_2025 huggingface dataset:
Correlation of Surface Geophysical and Logging Data of Some Selected Boreholes in Imo State, South Eastern Nigeria
Authors: Nwachukwu Patrick Chinyeaka , OKORO BON C , OSUAGWU JOACHIM CHINONYE , NWANKWO STEVE I
Published: December 2015

Boreholes have become a major source of water supply in South Eastern Nigeria, an area with diversity in geology, topography and climatic conditions. The common approaches in borehole investigations are surface survey and logging. The two approaches are supposed to be complementary. However, for small schemes of groundwater development, logging is hardly considered.. Six boreholes were selected from locations at the three geographical zones of Imo state. The selected locations are Umueze, Umuduru, Ogbor-Ugiiri, Ngor Okpuala and Eziama. Geophysical survey and logging were carried out. Electrical resistivity method was adapted for geophysical survey. ABEM Terrameter (SAS) 300B with digital read-out was used for logging. The degree of correlation between the variables was determined by computing the coefficient of correlation denoted as R2. The results indicate generally poor correlations between logging and geophysical surface values for the selected boreholes except for the one located at Ngor Okpala with R2 value of 0.7408. At this location, geophysical surface method for borehole locations can be carried without any Logging exercise to establish the Total Drilling Depth (TDD). This will help reduce the total cost for the drilling of the boreholes and also save time and much desired energy. In those areas where no correlation exists, there is need for Government Financial support in drilling sustainable borehloes as much costs are involved in investigation and construction works.
Low Impact Development and Transportation in the City of Mesa, AZ
Authors: Angelica Deeb Maria
Published: December 2015

The Cities of Mesa and Glendale, with a grant from the Water Infrastructure Finance Authority of Arizona (WIFA), partnered and developed a Low Impact Development (LID) Toolkit. This toolkit is a 100 page document that responds to the need to better manage the storm water runoff and reduce the need for very expensive expansion of drainage infrastructure. The solution to this problem justifies the need to use LID in Mesa. In 2014 the City of Mesa experienced flooding which affected many. Although LID solutions was considered at the time of this flooding event, it became a priority to identify potential solutions. The LID toolkit responded to this and is intended to minimize the harmful impacts of flooding by setting best practices related to the management of the rainfall-runoff process. The LID toolkit identifies and lists best storm-water City of Mesa management practices and national and regional LID best practices. This list and publication is intended to encourage City and private planners, designers and residents alike towards the practice of more sustainable design. The article presents the history of LID design and discusses the benefits of using LID tools.
The Modification and Evaluation of the Alexander-Govern Test in Terms of Power
Authors: Kingsley Ochuko Tobi , Abdullah Suhaida , Binti Zain Zakiyah , Soaad Syed Yahaya Sharipah
Published: December 2015

This study centres on the comparison of independent group tests in terms of power, by using parametric method, such as the Alexander-Govern test. The Alexander-Govern (AG) test uses mean as its central tendency measure. It is a better alternative compared to the Welch test, the James test and the ANOVA, because it produces high power and gives good control of Type I error rates for a normal data under variance heterogeneity. But this test is not robust for a non-normal data. When trimmed mean was applied on the test as its central tendency measure under non-normality, the test was only robust for two group condition, but as the number of groups increased more than two groups, the test was no more robust. As a result, a highly robust estimator known as the MOM estimator was applied on the test, as its central tendency measure. This test is not affected by the number of groups, but could not control Type I error rates under skewed heavy tailed distribution. In this study, the Winsorized MOM estimator was applied in the AG test, as its central tendency measure. A simulation of 5,000 data sets were generated and analysed on the test, using the SAS package. The result of the analysis, shows that with the pairing of unbalanced sample size of (15:15:20:30) with equal variance of (1:1:1:1) and the pairing of unbalanced sample size of (15:15:20:30) with unequal variance of (1:1:1:36) with effect size index (f = 0.8), the AGWMOM test only produced a high power value of 0.9562 and 0.8336 compared to the AG test, the AGMOM test and the ANOVA respectively and the test is considered to be sufficient.
The Design of a Shell-Tube Heat Exchanger as Evaporator an Absorption Chiller Cycle to Reduce the Temperature of the Air Entering a Diesel Engine Operating at Full Load Engine Medium
Authors: Sepideh Ghaffari Seyedeh , Ali Jazayeri Seyed
Published: December 2015

Survey, design evaporator heat exchanger is an absorption chiller cycle. To cooling air to a four-cylinder diesel engine medium, at full load at different speeds to increase the useful power output. Heat can be recycled to cooling air to the engine, by the absorption chiller, cooling to be converted. By reducing the engine inlet air temperature by evaporating, at full load, increased air density. And consequently more engine volumetric efficiency. As a result, the effective power output increases. In this study, the design of the structure of the evaporator, Solid Works was done by software. And the relationship between formulas and equations of heat transfer in the MATLAB code and the output results is provided in this article.
Seemingly Unrelated Regression Equations for Developing a Pavement Performance Model
Authors: Caliendo Ciro , Guida Maurizio , Pepe Emiliana
Published: December 2015

The paper presents a joint analysis of some pavement performance indicators based on a system of seemingly unrelated regression equations (SURE) which allows to handle correlated error terms. In particular, three major indicators such as the side friction coefficient (SFC20°C), mean-profile depth (MPD), and international roughness index (IRI), were measured in a case study and subsequently used in analysis. Regression parameters were estimated by the Maximum Likelihood Method and the t-statistic was considered to show the statistical significance of regression coefficients. The results show that estimation points have the signs expected: the SFC20°C decreases as the number of accumulated trucks (Nt) increases; whereas the MPD and IRI increase as the number of trucks increases. A likelihood ratio test was also carried out to determine whether the system model, which assumes correlation among error terms, was more appropriate than separate models. In this particular case, with three degrees of freedom, was found that the result corresponds to a p-value 0.150 and the null hypothesis cannot be rejected at any significance level less than this value.
Determining Thermal Specifications for Vegetated GREEN Roofs in Moderate Winter Climates
Authors: Ravesloot Christoph Maria
Published: December 2015

Because local weather conditions in moderate climates are changing constantly, heat transfer specifications of substrate and vegetation in vegetated green roofs also change accordingly. Nevertheless, it is assumed that vegetated green roofs can have a positive effect on the thermal performance of construction in winter conditions. Is there proof from scientific research and field testing for this assumption? To answer this question, research is conducted with the main research question: Which parameters defining thermal performance for vegetated green-roof construction for a moderate winter climate like that in the Netherlands can be determined from existing literature, and how do these parameters influence thermal performance? Literature research was executed on monitoring and testing of thermal specifications of vegetated green roofs. Models with physical parameters on vegetated green roofs were studied and compared. The first goal was to make a list of all physical parameters and corresponding variables valid in the Dutch moderate-winter climate. None of the models that were found in the literature seemed to cover all physical processes. These models use parameters and variables to calculate the overall u-value of substrate and vegetation. Nevertheless, one nearly complete model was used for a sensitivity test on variables. Maximum and minimum values of variables were calculated in the model to determine the influence on the outcome in terms of u-value. From this analysis, a distinction could be made between variables influencing the u-value strongly and other variables influencing the outcome weakly.

The modelling showed that three variables were influencing the model calculations moderately strongly and therefore the thermal performance of the vegetated green-roof substrate and vegetation. These variables are not consistent with parameters modeling or calculating u-value in constructions. This finding means that contribution to thermal insulation by extensive vegetated green-roof substrate and vegetation in terms of u-value would be negligible. Only a small theoretical contribution to thermal insulation can be argued from weak variables. To be sure about this small theoretical contribution to the u-value of the roof construction, this u-value was used as input for energy-use calculations for residential buildings. These calculations show that such a small increase of the u-value leads to no visible reduction in energy use for heating in winter conditions. The contribution is negligible compared to the influence of the u-value from extra insulation under the roof.
For vegetated green roofs in such moderate winter climates as in the Netherlands, additional u-value will have to be proven specifically, because the modelling shows that, in general, no contribution to thermal insulation can be expected.
Comprehensive Planning of Urban Housing in Metropolises by Focusing on Urban Integrated Management
Authors: Mohammadreza Talakesh Seyed , Mohammadi Jamal , Zangiabadi Ali
Published: December 2015

Many scholars of urban studies believe that the most important factor effective on the amount of individuals' welfare is housing.  Population increase of Iran and the expansion of the range of cities in Iran in recent decades cause centralization and increase in population densities in Iran and it seems that during recent years, economic policies of housing, as the interface ring for spatial planning policies of lands and urban and rural development, has been to some extent neglected by Iran's planning officials. Considering the multidimensionality of the issue of housing, for urban housing planning the intervention of different state and urban organizations is required and the lack of a comprehensive and integrated management is tangible in this issue. Regarding the domination of municipalities over internal issues of cities and also regarding geographical, political, economic and social conditions of different cities, municipalities can burden the responsibility of this issue. The objective of the present study is to investigate the problem of housing in Iran and providing an appropriate strategy for resolving this issue. Accordingly, the study, by doing library research, administering interviews and consulting state authorities and elites of housing markets and also by using the authors' scientific and executive experiences, an organizational structure was suggested for solving the housing issue. Then, by preparing questionnaires and surveying three groups (citizens, state and municipality authorities and academic specialists) this structure was evaluated using matrix QSPM and the SWOT model. Finally, by using the conducted surveys, the desired strategies were presented for improving the performance of organizational structure.
Training the Trainer in Australia – A Critical Analysis
Authors: Paul Maj Stanislaw
Published: December 2015

Within the Australian Further Education sector lecturers are required to complete the Certificate IV in Training and Assessment (TAE40110). Whilst it is recognized that lecturers in this sector are required to meet the needs of a wide diversity of students the ability to deliver training and conduct workshops is of paramount importance. There are a number of problems with studying the TAE that include insufficient weighting of units concerned with pedagogy and variable contact hours. The result is lecturers who complete the TAE may not be adequately prepared to conduct their role as teachers and trainers.
Molecular Cloning, Characterization, and Expression Analysis of DROOPING LEAF gene in the Pistillody Line of Common Wheat
Authors: Zhang Li , Yang Zaijun , Peng Zhengsong , Yu Yan , Sun Qingxu
Published: December 2015

In this article, we report the cloning, characterization, and expression pattern of Triticum aestivum DROOPING LEAF gene (TaDL) in pistillody line of common wheat. Three TaDL homoeologous genes (TaDL1, TaDL2, and TaDL3) were isolated and found to be located on chromosomes 4AS, 4DL, and 4BL, respectively. The putative TaDL1, TaDL2, and TaDL3 protein were 22.4, 22.6, and 22.3 kDa, with theoretical pI of 9.04, 9.04, and 8.98 and containing two distinct domains, namely, a zinc-finger domain in the N-terminal region and a C-terminal YABBY domain. The genome sequence of the three homologous genes consisted seven exons and six introns. All the introns, except for intron VI, varied in length and sequence composition. Phylogenetic analysis revealed that TaDL was most closely related to the Brachypodium distachyon BdDL and Oryza sativa DL genes. The expression pattern analysis indicated that TaDL1, TaDL2, and TaDL3 have a higher expression levels in PS and P; however, the three genes are very rare in S. Thus, TaDL gene may contribute to pistil development. Moreover, overexpression of TaDL gene in stamens may cause complete or partial homeosis of stamens into pistils in wheat.
Preprocessing of Digitalized Engineering Drawings
Authors: Gramblicka Matus , Vasky Jozef
Published: December 2015

The concept of digital manufacturing assumes an application of digital technologies in the whole product life cycle. CAD product model replaced engineering drawing in digital manufacturing. In contemporary practice the engineering paper-based drawings are still archived. They could be digitalized and stored to one of the raster graphics format. After that they could be vectorized for interactive editing in the specific software system or for archiving in some of standard vector graphics file format. The vector format is suitable for 3D model generating too. The article deals with using of methods for preprocessing phase of digitalized engineering drawings vectorization process.
Tandeta(Trash): Bruno Schulz and the Micropolitics of Everyday Life
Authors: Gasyna George
Published: December 2015

InThe Street of Crocodiles, Bruno Schulz delineates a startling vision of his hometown of Drohobycz as a space governed by second-hand cast-offs of metropolitan modernity and posits the artist as a demiurge who reigns over an accumulation of matter. Seeking escape from the shabbiness and tedium of daily life, the narrator plunges into an imaginary zone of his own making, one marked by temporal distortion, spatial instability, and the superabundance of matter, trash in particular. In the province, trash—as well as other "trashy" objects (tandeta and Bylejakość)—can be put to novel creative uses. It is thus possible to speak of a poetics of trash, wherein civilizational detritus returns to the foreground as a productive mode of representation and of micropolitical resistance. It is reterritorialized in Schulz as an archive of individual longings and desires and an index of local achievement. Trash, then, both as physical tandeta and as a key component of dream-work, emerges as a unifying sign of Schulz's provincial poetics.
Design and Construction of a Specialised Biomimetic Robot in Multiple Swimming Gaits
Authors: Masoomi Sayyed Farideddin , Gutschmidt Stefanie , Gaume Nicolas , Guillaume Thomas , Eatwel Connor , Chen XiaoQi , Sellier Mathieu
Published: December 2015

Efficient cruising, manoeuvrability and noiseless performance of fish robots have been attracting people in various scientific realms. Accordingly, a number of fish robots are designed and fabricated so far. However, the existing robots are only capable of one gait of locomotion. This deficiency is addressed by UC-Ika 2 with multiple gaits of locomotion including cruising and manoeuvring that are inspired from two different fishes. This paper aims at presenting the design and fabrication process of UC-Ika 2. The swimming performance of the robot is tested and compared with its previous version UC-Ika 1.
A Grasp-Pose Generation Method Based on Gaussian Mixture Models
Authors: Wu Wenjia
Published: December 2015

A Gaussian Mixture Model (GMM)-based grasp-pose generation method is proposed in this paper. Through offline training, the GMM is set up and used to depict the distribution of the robot's reachable orientations. By dividing the robot's workspace into small 3D voxels and training the GMM for each voxel, a look-up table covering all the workspace is built with the x, y and z positions as the index and the GMM as the entry. Through the definition of Task Space Regions (TSR), an object's feasible grasp poses are expressed as a continuous region. With the GMM, grasp poses can be preferentially sampled from regions with high reachability probabilities in the online grasp-planning stage. The GMM can also be used as a preliminary judgement of a grasp pose's reachability. Experiments on both a simulated and a real robot show the superiority of our method over the existing method.
Creating Literacy Fairs: How Collaboration Helps Early Literacy Goals
Authors: Goodwin Janina
Published: December 2015

Early literacy, outreach, and community partnerships are three constant initiatives of many public libraries. And the Youth Services department of the Pueblo City-County (CO) Library District (PCCLD) is no exception.
Effect of Depth and Leakage-Pathway Flow Properties on Thermal Response to Leakage from CO2 Storage Zone
Authors: Zeidouni Mehdi , Nicot J. P. , Hovorka Susan D. , Nunez-Lopez Vanessa
Published: December 2015

Temperature can be used as a tracer to detect leakage of fluids from a CO2 storage zone. Brine leakage from the injection zone to an above-zone interval will induce a temperature increase as a result of geothermal gradient. Leakage of CO2 can induce a temperature decrease owing to the Joule-Thompson effect associated with pressure drop toward shallow zones. A larger pressure drop at shallower depths is associated with more CO2 expansion upon leakage and could induce more cooling and, hence, a stronger temperature signal. We investigate the strength of the temperature signal as a function of depth for two scenarios in which either a well or a fault acts as leakage pathway. The hydraulic properties of the leakage pathway, modeled as a fractured medium or as a porous medium, also impact the results. Using dual-porosity and dual-permeability models for which CO2 relative permeability and average absolute permeability are modeled higher than in the simple porous medium case, we study the effect of fractures on the temperature signal. The leakage rate increases significantly for dual medium models. However, the temperature change in above-zone interval does not change much as it depends on the pressure gradient which is reduced compared to the single-porosity medium case.

1. Introduction

The value of CO2 geological storage sites may be limited when defective wells and faults create pathways allowing migration out of the CO2 injection zone (IZ). Various monitoring techniques are available to assure storage quality and to detect and characterize leakage pathways. Leakage of CO2, brine, or their mixture can induce pressure and temperature changes in an above-zone monitoring interval (AZMI) that is separated from the IZ by a sealing confining layer. Monitoring of the pressure signal in the AZMI has provided information about leakage pathways (Zeidouni and Pooladi-Darvish 2012a, b, Sun et al. 2013, Jung, Zhou, and Birkholzer 2013, Haghighat et al. 2013). More recent work by Zeidouni et al. (Zeidouni, Nicot, and Hovorka 2014) investigated the potential for leakage detection on the basis of the AZMI's temperature signal. Results showed that the thermal signal is controlled by several processes, including Joule-Thompson (JT) effect, heat of dissolution/vaporization of CO2/water, temperature discrepancy between the injected and native fluids, geothermal gradient, and heat exchange with the surrounding rock-fluid system.
Optimization of Geological Carbon Sequestration in Heterogeneous Saline Aquifers through Managed Injection for Uniform CO2 Distribution
Authors: Tarrahi Mohammadali , Afra Sardar
Published: December 2015

To mitigate continued release of CO2 from anthropogenic sources, underground storage of carbon dioxide (CO2) is accepted worldwide as a promising and well-established technology. Due to increased concerns on CO2 emissions, there has been foremost importance in recent years on the development and establishment of safe, technologically feasible and economic geological carbon sequestration (GCS) technology. GCS has been practiced widely as a potentially practical climate change mitigation decision. For this purpose to dispose large amount of CO2 in economic and safe fashion for long term periods, deep ocean and geologic sequestration are considered viable options. Geologic sequestration is a potential technology to decrease released CO2 into the atmosphere through capturing CO2 from hydrocarbon emissions, transporting compressed CO2 from the source to the field, and injecting and storage of CO2 into the underground formation. While injecting CO2 into the formation, residual gas trapping and solubility trapping are the most important trapping mechanisms for CO2 storage in saline aquifers. The lack of information about the geological formation results in uncertainties in specifying the storage capacity of the formation and the safety of sequestered CO2 caused by leakage. These uncertainties influence the sequestration capacity and CO2 plume migration. Moreover, the sequestration efficiency is highly dependent on the injection strategy which includes injection rate, injection pressure, type of injection well employed and its trajectory. The goal of GCS is to maximize the sequestration capacity and minimize the CO2 plume migration by optimizing the GCS operation before progressing with its large scale deployment. Hence the objective of CO2 sequestration is to achieve a more uniform sweep efficiency and more extensive CO2 sweep of the geological formation for a fixed amount of injected CO2. To accomplish this objective, we propose a novel formulation for CO2 sequestration optimization problem to promote uniform distribution of CO2 in geological formation through minimizing the gas saturation differences in cells with the same distance to CO2 injection wells.
Slowing light by activating an oscillatory mode in a negative refractive waveguide composed of all dielectric metamaterials
Authors: Huang Tsung-Yu , Lai Yueh-Chun , Yen Ta-Jen
Published: December 2015

We employ dielectric metamaterials to construct an all-dielectric negative refractive waveguide (NRW) in which the negative Goos–Hänchen effect is used to trap the incident wave in simulation. The use of a dielectric metamaterial eliminates the ohmic losses from metal, which not only lengthens photon-trapping time but also enables the NRW to maintain the ability to slow light. In addition, we validate numerical simulation with experimental measurements, which agree with the simulation results with a frequency offset of <1.2%. Finally, by verifying that light is slowed in an all-dielectric NRW, we claim that a dielectric metamaterial can possess negative identities.
First-principles study of metal–insulator control by ion adsorption on Ti2C MXene dioxide monolayers
Authors: Ando Yasunobu , Watanabe Satoshi
Published: December 2015

Through first-principles calculations using density functional theory, we investigate the possibility of controlling the metal–insulator properties of the Ti2C MXene dioxide Ti2CO2 by ion adsorption. Our simulation reveals that Ti2CO2 is insulating with an indirect band gap of 0.44 eV. Upon atomic adsorption of H, Li, or Na, Ti2CO2 becomes metallic. This metal–insulator change may be used to produce switching devices with a high on/off ratio and low energy consumption by controlling ionic movement, as in ion batteries.
“Otherness” of Ethnic Enclave Attractions in Multicultural Cities: A Study of Chinatown and Little India
Authors: Khan Sonia
Published: December 2015

For ages, tourists have been fascinated with “Other” cultures making it a primary reason for international travel. Several destinations around the world are blessed with cultural pluralism and proudly boast of being “multicultural”. These destinations comprise multiethnic migrant communities living in their respective “ethnic enclave” settings in a foreign land. Enclaves enrich the tourism product by pleasantly punctuating the cultural homogeneity of a destination and inviting attention towards other diverse exotic attractions. This study is an attempt to identify the distinct impressions of the ethnic enclave attractions of “Chinatown” and “Little India” in Kuala Lumpur and Singapore city, in order to determine the imprints of “otherness” left behind in the minds of tourists during their visits to these enclaves. The findings reveal that while authentic ethnic cuisine retains a dominant appeal of the “exotic other”, additional elements of cultural exoticism from these enclave settings are fast fading into oblivion. Rather than being identified as a showcase of a unique culture, the otherness of these ethnic enclave attractions is becoming more apparent in terms of their recognition merely as precincts for “inexpensive shopping”.
Mougeotia (Zygnemaceae, Streptophyta) in Australia
Authors: Skinner Stephen , Entwisle Timothy John
Published: December 2015

Thirteen taxa in the genus Mougeotia are described here for the Australian flora, and their distributions delineated. Many are new reports of taxa found in other parts of the world; some are reinstatements of previously reported species, like M. nummularioides, M. viridis and M. capucina, while there are three new varieties, M. laetevirens var. trochleifera, M. drouetii var. djelkiensis and M. tumidula var. palmerstoniana. This brings the verified species count for the continent to eighteen.
Recent tree die‐off has little effect on streamflow in contrast to expected increases from historical studies
Authors: Biederman Joel A. , Somor Andrew J. , Harpold Adrian A. , Gutmann Ethan D. , Breshears David D. , Troch Peter A. , Gochis David J. , Scott Russell L. , Meddens Arjan J. H. , Brooks Paul D.
Published: December 2015

Recent bark beetle epidemics have caused regional‐scale tree mortality in many snowmelt‐dominated headwater catchments of western North America. Initial expectations of increased streamflow have not been supported by observations, and the basin‐scale response of annual streamflow is largely unknown. Here we quantified annual streamflow responses during the decade following tree die‐off in eight infested catchments in the Colorado River headwaters and one nearby control catchment. We employed three alternative empirical methods: (i) double‐mass comparison between impacted and control catchments, (ii) runoff ratio comparison before and after die‐off, and (iii) time‐trend analysis using climate‐driven linear models. In contrast to streamflow increases predicted by historical paired catchment studies and recent modeling, we did not detect streamflow changes in most basins following die‐off, while one basin consistently showed decreased streamflow. The three analysis methods produced generally consistent results, with time‐trend analysis showing precipitation was the strongest predictor of streamflow variability (R2 = 74–96%). Time‐trend analysis revealed post‐die‐off streamflow decreased in three catchments by 11–29%, with no change in the other five catchments. Although counter to initial expectations, these results are consistent with increased transpiration by surviving vegetation and the growing body of literature documenting increased snow sublimation and evaporation from the subcanopy following die‐off in water‐limited, snow‐dominated forests. The observations presented here challenge the widespread expectation that streamflow will increase following beetle‐induced forest die‐off and highlight the need to better understand the processes driving hydrologic response to forest disturbance.
Mechanism of Gas Separation through Amorphous Silicon Oxycarbide Membranes
Authors: Prasad Ravi Mohan , Jüttke Yvonne , Richter Hannes , Voigt Ingolf , Riedel Ralf , Gurlo Aleksander
Published: December 2015

Polymer‐derived amorphous silicon oxycarbide (SiOC) ceramics are designed for hydrogen separation at high temperatures. To form amorphous SiOC top‐coating with the thickness of about 300 nm, tubular porous γ‐Al2O3/α‐Al2O3 substrates with gradient porosity are threefold coated by vinyl‐functionalized polysiloxane and pyrolyzed at 700 °C under argon. N2‐physisorption measurement confirms formation of microporous material with a specific surface area of about 400 m2 g–1. Single gas permeance characterization of the SiOC membrane at 300 °C reveals H2/CO2 and H2/SF6 ideal permselectivities of about 10 and 320, respectively. The experimental gas permeance data are modeled using solid‐state diffusion (for He and H2) and gas translational diffusion (for CO2 and SF6) mechanisms.
Ionizing Radiation Detectors Based on Solution‐Grown Organic Single Crystals
Authors: Fraboni Beatrice , Fraleoni‐Morgera Alessandro , Zaitseva Natalia
Published: December 2015

Organic single crystals (OSCs) have ideal qualities (well defined structure and morphology, lack of grain boundaries, high purity, 3D long range order, good electronic transport properties) for several technological applications, in particular as key components for electronic devices. It is only recently that OSCs have been considered as ionizing radiation detectors, and the latest developments in this field are here reported. In the first section, various methods for OSC growth are described, with emphasis on cost‐effective, solution‐based approaches capable of delivering large volume, well performing crystals. The second section is focused on the use of solution‐grown OSCs as scintillators (i.e., as high energy photon to UV–vis photon conversion), highlighting the ability of cm‐scale OSCs to effectively detect neutrons and to carry out neutrons‐gamma pulse‐shape discrimination tasks. Finally, the third section describes the use of semiconducting, solution‐grown OSCs as effective solid state direct detectors (i.e., directly converting high energy photons into charge carriers), evidencing extremely promising performances in terms of operability in environmental conditions (i.e., no need for encapsulation), radiation hardness, linear response and low operating voltage.
3D Single‐Molecule Imaging of Transmembrane Signaling by Targeting Nanodiamonds
Authors: Liu Wenliang , Yu Fenglei , Yang Jianbo , Xiang Bo , Xiao Peng , Wang Li
Published: December 2015

Fluorescent nanodiamonds (FNDs) have recently emerged as promising probes for imaging applications. A significant limitation of the applications is the use of FNDs as endogenous protein tags for long‐term 3D single molecule imaging to gain critical understanding of the underlying mechanism such as transmembrane signaling. Here, FNDs conjugated with transforming growth factor (TGF) are developed as an imaging probe for endogenous TGF‐beta (TGF‐β) receptor labeling and 3D single molecule imaging. FNDs display higher localization accuracy in 3D than organic dye making it an ideal candidate for nanoscopy applications. The real‐time dynamics of TGF‐β receptors after binding conjugated FNDs and in cells treated with therapeutic small molecule kinase inhibitors (SMI) are further monitored. The Bayesian treatment of hidden Markov models confirms and quantifies three different diffusive states and the transition rates between the three states. The kinetic reaction favors a faster diffusion population after therapeutic SMI treatment. The results show that immobilized TGF‐β is critical for active signaling. SMI treatment can release TGF‐β from the signaling complex. The results demonstrate the reported method that provides a powerful technique to study the mechanism of transmembrane signaling and valuable insights for developing better therapeutic for TGF‐β‐associated cancers.
Hydrogenated V2O5 Nanosheets for Superior Lithium Storage Properties
Authors: Peng Xiang , Zhang Xuming , Wang Lei , Hu Liangsheng , Cheng Samson Ho‐Sum , Huang Chao , Gao Biao , Ma Fei , Huo Kaifu , Chu Paul K.
Published: December 2015

V2O5 is a promising cathode material for lithium ion batteries boasting a large energy density due to its high capacity as well as abundant source and low cost. However, the poor chemical diffusion of Li+, low conductivity, and poor cycling stability limit its practical application. Herein, oxygen‐deficient V2O5 nanosheets prepared by hydrogenation at 200 °C with superior lithium storage properties are described. The hydrogenated V2O5 (H‐V2O5) nanosheets deliver an initial discharge capacity as high as 259 mAh g−1 and it remains 55% when the current density is increased 20 times from 0.1 to 2 A g−1. The H‐V2O5 electrode has excellent cycling stability with only 0.05% capacity decay per cycle after stabilization. The effects of oxygen defects mainly at bridging O(II) sites on Li+ diffusion and overall electrochemical lithium storage performance are revealed. The results reveal here a simple and effective strategy to improve the capacity, rate capability, and cycling stability of V2O5 materials which have large potential in energy storage and conversion applications.
Flexible Photodetectors Based on 1D Inorganic Nanostructures
Authors: Lou Zheng , Shen Guozhen
Published: December 2015

Flexible photodetectors with excellent flexibility, high mechanical stability and good detectivity, have attracted great research interest in recent years. 1D inorganic nanostructures provide a number of opportunities and capabilities for use in flexible photodetectors as they have unique geometry, good transparency, outstanding mechanical flexibility, and excellent electronic/optoelectronic properties. This article offers a comprehensive review of several types of flexible photodetectors based on 1D nanostructures from the past ten years, including flexible ultraviolet, visible, and infrared photodetectors. High‐performance organic‐inorganic hybrid photodetectors, as well as devices with 1D nanowire (NW) arrays, are also reviewed. Finally, new concepts of flexible photodetectors including piezophototronic, stretchable and self‐powered photodetectors are examined to showcase the future research in this exciting field.
Improper Inversion Symmetry Breaking and Piezoelectricity through Oxygen Octahedral Rotations in Layered Perovskite Family, LiRTiO4 (R = Rare Earths)
Authors: Gupta Arnab Sen , Akamatsu Hirofumi , Strayer Megan E. , Lei Shiming , Kuge Toshihiro , Fujita Koji , dela Cruz Clarina , Togo Atsushi , Tanaka Isao , Tanaka Katsuhisa , Mallouk Thomas E. , Gopalan Venkatraman
Published: December 2015

An improper mechanism for breaking inversion symmetry is revealed and thus inducing piezoelectricity in the family of layered perovskites, LiRTiO4 (R = rare earths), which are previously reported as centrosymmetric. Noncentrosymmetry in this family of compounds arises from TiO6 octahedral rotation represented by a−boco/boa−co in the perovskite blocks between RO rock salt and LiO antifluorite layers. X‐ray diffraction and optical second harmonic generation complemented by density functional theory predictions are crucial in determining the new structures. High transition temperature (Tac) of up to 1200 K from noncentrosymmetric to centrosymmetric phase is observed. Piezoelectric coefficients (d36) of up to −15 pC/N are predicted, and piezoelectric force microscopy experiments confirm a piezoelectric response. The demonstrated improper mechanism in this and other layered oxide families, with a wide range of available topologies and chemistries, could aid in the search for high temperature piezoelectrics.
Synthesis of Acyclic Selenonucleoside Phosphonates as Potential Antiviral Agents
Authors: Sahu Pramod K. , Kim Gyudong , Nayak Akshata , Ahn Ji Yoon , Ha Min Woo , Park Cheonhyoung , Yu Jinha , Park Hyeung‐geun , Jeong Lak Shin
Published: December 2015

On the basis of potent antiviral activity of adefovir (1) and tenofovir (2), which are representative acyclic nucleoside phosphonates, bioisosteric acyclic selenonucleoside phosphonates seleno‐adefovir (3) and seleno‐tenofovir (4) were designed and synthesized from diethyl(iodomethyl)phosphonate (7) by using diselenide chemistry.
One‐Pot Synthesis of Oxazolidine Derivatives by [3+2]‐Annulation Reactions of 1‐Tosyl‐2‐phenyl/alkylaziridines with Aryl Epoxides
Authors: Pandey Ashok Kumar , Banerjee Prabal
Published: December 2015

An efficient method for the synthesis of oxazolidine derivatives from aziridines and in situ generated aldehydes from Meinwald rearrangements of the epoxides has been developed. This method gives easy access to functionalized oxazolidines, which are constitutional moieties present in several natural products and biologically active molecules. The scope of the title transformation has also been elaborated with a variety of substrates.
The Effect of Pyridyl Nitrogen Atom Position in Pyrido[3,4‐b]pyrazines in Donor‐Acceptor‐π‐Acceptor Dyes on Absorption, Energy Levels, and Photovoltaic Performances of Dye‐Sensitized Solar Cells
Authors: Zhou Ying , Li Xing , Li Xin , Chen Jue , Yu Fengtao , Hua Jianli
Published: December 2015

A donor‐acceptor‐π‐acceptor (D‐A‐π‐A)‐type organic dye (DTN‐1) incorporating a pyrido[3,4‐b]pyrazine (PP) unit with the pyridyl N atom adjacent to the anchoring group has been synthesized for use in dye‐sensitized solar cells (DSSCs). The maximum absorption wavelength of DTN‐1 was clearly red‐shifted compared with dye DT‐1, based on PP unit with the pyridyl N atom adjacent to the donor group. However, this change of structure has a negative effect on photovoltaic performances, and devices made with DTN‐1 only reached a power conversion efficiency of 6.10 % under AM1.5G irradiation compared with 8.57 % achieved by DT‐1. Density functional theory calculations suggest that DTN‐1 has a smaller oscillator strength, which is connected to its relatively low light‐harvesting efficiency. In addition, the results of electrochemical impedance spectroscopy (EIS) reveal that charge recombination in DSSCs based on DTN‐1 is more than that in the counterpart DT‐1, thus leading to a lower open‐circuit voltage (Voc).
Minimal spaser threshold within electrodynamic framework: Shape, size and modes
Authors: Arnold Nikita , Hrelescu Calin , Klar Thomas A.
Published: December 2015

It is known (yet often ignored) from quantum mechanical or energetic considerations, that the threshold gain of the quasi‐static spaser depends only on the dielectric functions of the metal and the gain material. Here, we derive this result from the purely classical electromagnetic scattering framework. This is of great importance, because electrodynamic modelling is far simpler than quantum mechanical one. The influence of the material dispersion and spaser geometry are clearly separated; the latter influences the threshold gain only indirectly, defining the resonant wavelength. We show that the threshold gain has a minimum as a function of wavelength. A variation of nanoparticle shape, composition, or spasing mode may shift the plasmonic resonance to this optimal wavelength, but it cannot overcome the material‐imposed minimal gain. Furthermore, retardation is included straightforwardly into our framework; and the global spectral gain minimum persists beyond the quasi‐static limit. We illustrate this with two examples of widely used geometries: Silver spheroids and spherical shells embedded in and filled with gain materials.
Hexameric Capsules Studied by Magic Angle Spinning Solid‐State NMR Spectroscopy: Identifying Solvent Molecules in Pyrogallol[4]arene Capsules
Authors: Avram Liat , Goldbourt Amir , Cohen Yoram
Published: December 2015

Powders of pyrogallol[4]arene hexamers were produced by evaporation from organic solvents and were studied, for the first time, by magic angle spinning solid‐state NMR (MAS ssNMR). Evaporation selectively removed non‐encapsulated solvent molecules leaving stable hexameric capsules encapsulating solvent molecules. After exposure of the powder to solvent vapors, 1H/13C heteronuclear correlation MAS ssNMR experiments were used to assign the signals of the external and encapsulated solvent molecules. The formed capsules were stable for months and the process of solvent encapsulation was reversible. According to the ssNMR experiments, the encapsulated solvent molecules occupy different sites and those sites differ in their mobility. The presented approach paves the way for studying guest exchange, guest affinity, and gas storage in hexamers of this type in the solid state.
Templated Chromophore Assembly by Dynamic Covalent Bonds
Authors: Rocard Lou , Berezin Andrey , De Leo Federica , Bonifazi Davide
Published: December 2015

Through the simultaneous use of three orthogonal dynamic covalent reactions, namely disulfide, boronate, and acyl hydrazone formation, we conceived a facile and versatile protocol to spatially organize tailored chromophores, which absorb in the blue, red, and yellow regions, on a preprogrammed α‐helix peptide. This approach allowed the assembly of the dyes in the desired ratio and spacing, as dictated by both the relative positioning and distribution of the recognition units on the peptide scaffold. Steady‐state UV/Vis absorption and emission studies suggest an energy transfer from the yellow and red donors to the blue acceptor. A molecular dynamics simulation supports the experimental findings that the helical structure is maintained after the assembly and the three dyes are confined in defined conformational spaces.
C‐Alkylierung von Ketonen und verwandten Verbindungen durch Alkohole: übergangsmetallkatalysierte Dehydrierung
Authors: Huang Fei , Liu Zhuqing , Yu Zhengkun
Published: December 2015

Die übergangsmetallkatalysierte C‐Alkylierung von Ketonen und sekundären Alkoholen mit Alkoholen umgeht den Einsatz von metallorganischen oder umweltschädlichen Alkylierungsreagentien über die Borrowing‐Hydrogen(BH)‐ oder Hydrogen‐Autotransfer(HA)‐Aktivierung der Alkoholsubstrate. Da Wasser als einziges Begleitprodukt entsteht, ist das BH‐Verfahren atomökonomisch und umweltfreundlich. Viele homogene und heterogene Übergangsmetallkatalysatoren, Ketone und Alkohole sind in dieser Reaktion einsetzbar, sodass das BH‐Verfahren aussichtsreich scheint, die derzeitigen Verfahren zu ersetzen, die herkömmliche Alkylierungsreagentien verwenden. Dieser Kurzaufsatz fasst die Fortschritte in der übergangsmetallkatalysierten α‐Alkylierung von Ketonen und β‐Alkylierung von sekundären Alkoholen mit Alkoholen mithilfe der BH‐Technik während der letzten fünf Jahre zusammen. Auch die Eignung der BH‐Strategie zur C‐C‐Bindungsbildung wird diskutiert.
Spectra Library: An Assumption‐Free In Situ Method to Access the Kinetics of Catechols Binding to Colloidal ZnO Quantum Dots
Authors: Lin Wei , Haderlein Michael , Walter Johannes , Peukert Wolfgang , Segets Doris
Published: December 2015

Assumption‐free and in situ resolving of the kinetics of ligand binding to colloidal nanoparticles (NPs) with high time resolution is still a challenge in NP research. A unique concept of using spectra library and stopped‐flow together with a “search best‐match” Matlab algorithm to access the kinetics of ligand binding in colloidal systems is reported. Instead of deconvoluting superimposed spectra using assumptions, species absorbance contributions (ligand@ZnO NPs and ligand in solution) are obtained by offline experiments. Therefrom, a library of well‐defined targets with known ligand distribution between particle surface and solution is created. Finally, the evolution of bound ligand is derived by comparing in situ spectra recorded by stopped‐flow and the library spectra with the algorithm. Our concept is a widely applicable strategy for kinetic studies of ligand adsorption to colloidal NPs and a big step towards deep understanding of surface functionalization kinetics.
Light‐Induced Reversible Self‐Assembly of Gold Nanoparticles Surface‐Immobilized with Coumarin Ligands
Authors: He Huibin , Feng Miao , Chen Qidi , Zhang Xinqi , Zhan Hongbing
Published: December 2015

A novel light‐induced reversible self‐assembly (LIRSA) system is based on the reversible photodimerization and photocleavage of coumarin groups on the surface of gold nanoparticles (AuNPs) in THF solution. Facilitated by coumarin groups, light irradiation at 365 nm triggers the stable assembly of monodisperse AuNPs; the resulting self‐assembly system can be disassembled back to the disassembled state by a relatively short exposure to benign UV light. The reversible self‐assembly cycle can be repeated 4 times. A specific concentration range of coumarin ligand and the THF solvent were identified to be the two predominant factors that contribute to the LIRSA of AuNPs. This is the first successful application of reversible photodimerization based on a coumarin derivative in the field of AuNP LIRSA. This LIRSA system may provide unique opportunities for the photoregulated synthesis of many adjustable nanostructures and devices.
Asymmetric Allylic Alkylation of β‐Ketoesters with Allylic Alcohols by a Nickel/Diphosphine Catalyst
Authors: Kita Yusuke , Kavthe Rahul D. , Oda Hiroaki , Mashima Kazushi
Published: December 2015

Asymmetric allylic alkylation of β‐ketoesters with allylic alcohols catalyzed by [Ni(cod)2]/(S)‐H8‐BINAP was found to be a superior synthetic protocol for constructing quaternary chiral centers at the α‐position of β‐ketoesters. The reaction proceeded in high yield and with high enantioselectivity using various β‐ketoesters and allylic alcohols, without any additional activators. The versatility of this methodology for accessing useful and enantioenriched products was demonstrated.
Universelle Methode zur Herstellung von Aerogelen aus kolloidalen Nanopartikellösungen durch Einfrieren und anschließendes Gefriertrocknen
Authors: Freytag Axel , Sánchez‐Paradinas Sara , Naskar Suraj , Wendt Natalja , Colombo Massimo , Pugliese Giammarino , Poppe Jan , Demirci Cansunur , Kretschmer Imme , Bahnemann Detlef W. , Behrens Peter , Bigall Nadja C.
Published: December 2015

In dieser Zuschrift wird über eine universelle Methode zur Herstellung von selbsttragenden Aerogelen aus kolloidalen Nanopartikeln (NP) berichtet. Dafür werden die NP eingefroren und anschließend gefriergetrocknet. Das bedeutet, dass die kolloidalen NP ohne vorherige Gelierung (wie bisher bei herkömmlichen Aero‐ und Kryogel‐Verfahren üblich) direkt in trockene, aerogelähnliche monolithische Überstrukturen überführt werden können. Die Anordnung der NP zu einer Überstruktur ist ein rein physikalischer Prozess und dadurch vielfältig einsetzbar, was bedeutet, dass die Kryogelierung auf Edelmetall‐, Metalloxid‐ und Halbleiter‐NP angewendet werden kann. Die Kryogelierung beeinflusst die Oberflächenchemie oder die NP‐Form in der entstehenden Morphologie dabei nicht. Unter idealen Bedingungen sind auch die Volumina und die Formen von gefrorenem NP‐Kolloid und Aerogel gleich groß. Dies ermöglicht es, mit der Methode dünne, gleichmäßige Aerogelfilme und andere Geometrien von Aerogelmonolithen herzustellen. Abschließend werden die physikochemischen Eigenschaften der Aerogele diskutiert.