Preferred Alignment Research Articles

In situ synchrotron high-energy X-ray diffraction study of microscopic deformation behavior of a hard-soft dual phase composite containing phase transforming matrix

This study explored a novel intermetallic composite design concept based on the principle of lattice strain matching enabled by the collective atomic load transfer. It investigated the hard-soft microscopic deformation behavior of a Ti3Sn/TiNi eutectic hard-soft dual phase composite by means of in situ synchrotron high-energy X-ray diffraction (HE-XRD) during compression. The composite provides a unique micromechanical system with distinctive deformation behaviors and mechanisms from the two components, with the soft TiNi matrix deforming in full compliance via martensite variant reorientation and the hard Ti3Sn lamellae deforming predominantly by rigid body rotation, producing a crystallographic texture for the TiNi matrix and a preferred alignment for the Ti3Sn lamellae. HE-XRD reveals continued martensite variant reorientation during plastic deformation well beyond the stress plateau of TiNi. The hard and brittle Ti3Sn is also found to produce an exceptionally large elastic strain of 1.95% in the composite. This is attributed to the effect of lattice strain matching between the transformation lattice distortion of the TiNi matrix and the elastic strain of Ti3Sn lamellae. With such unique micromechanic characteristics, the composite exhibits high strength and large ductility.

Tracing the Magnetic Field of IRDC G028.23-00.19 Using NIR Polarimetry

Abstract The importance of the magnetic (B) field in the formation of infrared dark clouds (IRDCs) and massive stars is an ongoing topic of investigation. We studied the plane-of-sky B field for one IRDC, G028.23-00.19, to understand the interaction between the field and the cloud. We used near-IR background starlight polarimetry to probe the B field and performed several observational tests to assess the field importance. The polarimetric data, taken with the Mimir instrument, consisted of H-band and K-band observations, totaling 17,160 stellar measurements. We traced the plane-of-sky B-field morphology with respect to the sky-projected cloud elongation. We also found the relationship between the estimated B-field strength and gas volume density, and we computed estimates of the normalized mass-to-magnetic flux ratio. The B-field orientation with respect to the cloud did not show a preferred alignment, but it did exhibit a large-scale pattern. The plane-of-sky B-field strengths ranged from 10 to 165 μG, and the B-field strength dependence on density followed a power law with an index consistent with 2/3. The mass-to-magnetic flux ratio also increased as a function of density. The relative orientations and relationship between the B field and density imply that the B field was not dynamically important in the formation of the IRDC. The increase in mass-to-flux ratio as a function of density, though, indicates a dynamically important B field. Therefore, it is unclear whether the B field influenced the formation of G28.23. However, it is likely that the presence of the IRDC changed the local B-field morphology.

Thermal conductivity of electrospinning chain-aligned polyethylene oxide (PEO)

Polymer fibers' thermal conductivity along its axis direction are usually much better compared to that of the bulk. Many researches indicate that three main factors have significant impact on polymer fiber's thermal conductivity, which are crystallinity, molecular alignment and crystalline grain orientation of the polymer. Most research focus on polyethylene (PE) because of its relatively high crystallinity. Here, we report exceptionally high thermal conductivity on electrospun polyethylene oxide (PEO) nanofibers, which is an important semicrystalline polymer. This indicates that semicrystalline polymers like PEO can also obtain high thermal conductivity, which may be used in areas such as electronic devices. Its thermal conductivity improved about 150 times over bulk polymer. By using infrared spectroscopy, we evidenced that improvement in thermal conductivity was ascribed to increased molecular alignment. And we discussed the relationship between molecular alignment and crystalline grain orientation, as well as their contribution to the thermal conductivity of PEO fibers. We found that for PEO nanofibers, preferred molecular alignment in the amorphous region has significant contributed to high thermal conductivity.

Mobility of nanofiber, nanorod, and straight-chain nanoparticles in gases

ABSTRACTWith the fast development of nanotechnology, accurate measurement and classification of nanoparticles are in great need. Nanoparticles frequently appear in non-spherical forms such as long aspect ratio nanofibers, nanotubes, and irregular nano-agglomerates. While the well-developed classical studies were mainly in continuum regime with spherical particles, dynamics of the non-spherical nanoparticles is not fully understood. In this study, orientation-averaged mobility of nanofiber and nanorod (with no preferred alignment) is examined by the methods of Brownian diffusion theory, a combination of collision limited reaction rate theory and the bipolar diffusion charging analysis. Comparisons to empirical predictions from the experimental measurements are also made. The study leads to the discovery of a surface-dominated mobility for high aspect ratio nanoparticles with characteristic Knudsen number greater than 5. In view of the extreme relative length scales between particle size and the gas mean fr...

MARS: improving multiple circular sequence alignment using refined sequences

BackgroundA fundamental assumption of all widely-used multiple sequence alignment techniques is that the left- and right-most positions of the input sequences are relevant to the alignment. However, the position where a sequence starts or ends can be totally arbitrary due to a number of reasons: arbitrariness in the linearisation (sequencing) of a circular molecular structure; or inconsistencies introduced into sequence databases due to different linearisation standards. These scenarios are relevant, for instance, in the process of multiple sequence alignment of mitochondrial DNA, viroid, viral or other genomes, which have a circular molecular structure. A solution for these inconsistencies would be to identify a suitable rotation (cyclic shift) for each sequence; these refined sequences may in turn lead to improved multiple sequence alignments using the preferred multiple sequence alignment program.ResultsWe present MARS, a new heuristic method for improving Multiple circular sequence Alignment using Refined Sequences. MARS was implemented in the C++ programming language as a program to compute the rotations (cyclic shifts) required to best align a set of input sequences. Experimental results, using real and synthetic data, show that MARS improves the alignments, with respect to standard genetic measures and the inferred maximum-likelihood-based phylogenies, and outperforms state-of-the-art methods both in terms of accuracy and efficiency. Our results show, among others, that the average pairwise distance in the multiple sequence alignment of a dataset of widely-studied mitochondrial DNA sequences is reduced by around 5% when MARS is applied before a multiple sequence alignment is performed.ConclusionsAnalysing multiple sequences simultaneously is fundamental in biological research and multiple sequence alignment has been found to be a popular method for this task. Conventional alignment techniques cannot be used effectively when the position where sequences start is arbitrary. We present here a method, which can be used in conjunction with any multiple sequence alignment program, to address this problem effectively and efficiently.

Preferred cell alignment along concave microgrooves

The radius of curvature affects cell body characteristics on microfabricated concave microgrooves.

Bistable curvature potential at hyperbolic points of nematic shells

Nematic shells are colloidal particles coated with nematic liquid crystal molecules which may freely glide and rotate on the colloid's surface while keeping their long axis on the local tangent plane. We describe the nematic order on a shell by a unit director field on an orientable surface. Equilibrium fields can then be found by minimising the elastic energy, which in general is a function of the surface gradient of the director field. We learn how to extract systematically out of this energy a fossil component, related only to the surface and its curvatures, which expresses a curvature potential for the molecular torque. At hyperbolic points on the colloid's surface, and only there, the alignment preferred by the curvature potential may fail to be a direction of principal curvature. There the fossil energy becomes bistable.

Importance of the alignment of polar π conjugated molecules inside carbon nanotubes in determining second-order non-linear optical properties.

We employed density functional theory (DFT) calculations with dispersion corrections to investigate energetically preferred alignments of certain p,p'-dimethylaminonitrostilbene (DANS) molecules inside an armchair (m,m) carbon nanotube (n × DANS@(m,m)), where the number of inner molecules (n) is no greater than 3. Here, three types of alignments of DANS are considered: a linear alignment in a parallel fashion and stacking alignments in parallel and antiparallel fashions. According to DFT calculations, a threshold tube diameter for containing DANS molecules in linear or stacking alignments was found to be approximately 1.0 nm. Nanotubes with diameters smaller than 1.0 nm result in the selective formation of linearly aligned DANS molecules due to strong confinement effects within the nanotubes. By contrast, larger diameter nanotubes allow DANS molecules to align in a stacking and linear fashion. The type of alignment adopted by the DANS molecules inside a nanotube is responsible for their second-order non-linear optical properties represented by their static hyperpolarizability (β0 values). In fact, we computed β0 values of DANS assemblies taken from optimized n × DANS@(m,m) structures, and their values were compared with those of a single DANS molecule. DFT calculations showed that β0 values of DANS molecules depend on their alignment, which decrease in the following order: linear alignment > parallel stacking alignment > antiparallel stacking alignment. In particular, a linear alignment has a β0 value more significant than that of the same number of isolated molecules. Therefore, the linear alignment of DANS molecules, which is only allowed inside smaller diameter nanotubes, can strongly enhance their second-order non-linear optical properties. Since the nanotube confinement determines the alignment of DANS molecules, a restricted nanospace can be utilized to control their second-order non-linear optical properties. These DFT findings can assist in the design of nanotube-based materials exhibiting stronger non-linear optical properties.

The Use of Defaults in Green Electricity Markets - Evidence from a Laboratory Experiment

Green electricity defaults should steer individual choices to environmentally friendly alternatives and provide a match with individuals' preferences for an electricity mix. It is debatable whether green electricity defaults conform to this latter intention. Using two design elements from existing electricity markets, costly opt out of contracts and green electricity certificates, preferences for an electricity mix are elicited in an incentivized laboratory experiment. This study then assesses whether preferences in the absence of default options match with preferences in the presence of default options. It turns out that the alignment of default intentions and preferences depends on the price for green electricity. Low priced green electricity defaults, as currently applied in several electricity markets, do not match subjects' preferences. My findings are relevant for the design of green electricity defaults.

Product, process and customer preference alignment in prefabricated house building

Much of the extant literature exploits the customer order decoupling point (CODP) from an aggregate product level. We develop a systematic approach to determine the alignment of CODP configurations at product, category and component levels, with customer preferences in terms of their customisation requirements. We adopt a participatory research method incorporating focus groups and interviews with personnel from a German case study company that builds prefabricated houses. From this we determine the product architecture. We also undertake a customer preference survey utilising a questionnaire that is based on a paired comparison technique. The survey informs customer preferences for choice for various elements of the architecture. We find that while at the product level the company produces a house that as a whole offers a high degree of customisation, at a category or components levels there are various offerings from pure standardisation to pure customisation. Furthermore, there is not always alignment between what customers want and what is actually being offered by the customer. So the company has options in terms of reconfiguring its operations, design new products/categories/components and/or seeking new marketplace opportunities. While the research has developed a technique that determines the extent to which the CODP positioning for a product architecture is aligned against customer preferences, there is a need for further research to test our findings beyond a single case study and into other industry sector contexts.

Competition in Persuasion

We study symmetric information games where a number of senders choose what information to communicate. We show that the impact of competition on information revelation is ambiguous in general. We identify a condition on the information environment (i.e. the set of signals available to each sender) that is necessary and sufficient for equilibrium outcomes to be no less informative than the collusive outcome, regardless of preferences. The same condition also provides an easy way to characterize the equilibrium set and governs whether introducing additional senders or decreasing the alignment of senders' preferences necessarily increases the amount of information revealed.

Room temperature homeotropic alignment of mixed-stacking columns of H6TP donors and PDI acceptors by charge transfer interactions and size match

Room temperature mesophases were achieved by blending donors 2,3,6,7,10,11-hexakis-(hexyloxy)-triphenylene (H6TP) with acceptors N,N′-bis(1-heptyloctyl)-perylene-3,4,9,10-tetracarboxylic diimide (PDI) via charge transfer interactions and size match. Compared with H6TP (mesophase temperature range: 97°C–51°C) and PDI (119°C–108°C), H6TP/PDI=1/2 (138°C - room temperature), 1/1 (139°C–40°C) and 1/0.5 (130°C–31°C) blends showed increase of clearing points and decrease of crystallization temperatures with wide mesophase temperature ranges. Different from edge-on orientation of PDI and no preferred alignment of H6TP, face-on alignments of all mixtures films could be achieved and stable at room temperature by cooling from isotropic state. It was inferred that stabilised columnar mesophases of H6TP/PDI blends were caused by charge transfer (CT) interactions and size match of them in hexagonal columnar phases. The existence of CT interactions was demonstrated by upfield shifts of aromatic protons in the 1H NMR spectra of H6TP/PDI blends solutions and obvious fluorescent quenching in the blends films.

Time-resolved fluorescence and absence of Förster resonance energy transfer in ferroelectric liquid crystal-quantum dots composites

The present article deals with the interaction of octadecylamine (ODA) capped cadmium selenide quantum dots (CdSe QDs) and two ferroelectric liquid crystals (FLCs) having different values of spontaneous polarization (Ps). The pristine FLCs and FLC-QDs composites have been investigated by using steady-state and time-resolved fluorescence spectroscopic techniques. Stokes shift and the preferred alignment of FLC molecules in the presence of QDs are found to depend on the secondary order parameter of FLCs (i.e. Ps). The secondary fluorescence emissions have been strongly influenced by the concentration of QDs. The Förster resonance energy Transfer (FRET) was absent in both the composites. This article discloses the role of various factors, like relative orientation, dipolar interaction between donor and acceptor and the proximity of QDs (>10 nm), which might be responsible for the absence of FRET. FLC-QDs composites do not form a new class of luminescent material though the fluorescence properties of host FLCs are tailored in the presence of QDs by means of the change in molecular alignment. The change in lifetimes of FLC-QDs composites has not been observed.

FERMI LARGE AREA TELESCOPE DETECTION OF EXTENDED GAMMA-RAY EMISSION FROM THE RADIO GALAXY FORNAX A

ABSTRACT We report the Fermi Large Area Telescope detection of extended γ-ray emission from the lobes of the radio galaxy Fornax A using 6.1 years of Pass 8 data. After Centaurus A, this is now the second example of an extended γ-ray source attributed to a radio galaxy. Both an extended flat disk morphology and a morphology following the extended radio lobes were preferred over a point-source description, and the core contribution was constrained to be % of the total γ-ray flux. A preferred alignment of the γ-ray elongation with the radio lobes was demonstrated by rotating the radio lobes template. We found no significant evidence for variability on ∼0.5 year timescales. Taken together, these results strongly suggest a lobe origin for the γ-rays. With the extended nature of the γ-ray emission established, we model the source broadband emission considering currently available total lobe radio and millimeter flux measurements, as well as X-ray detections attributed to inverse Compton (IC) emission off the cosmic microwave background (CMB). Unlike the Centaurus A case, we find that a leptonic model involving IC scattering of CMB and extragalactic background light (EBL) photons underpredicts the γ-ray fluxes by factors of about ∼2–3, depending on the EBL model adopted. An additional γ-ray spectral component is thus required, and could be due to hadronic emission arising from proton–proton collisions of cosmic rays with thermal plasma within the radio lobes.

We can all get along: The alignment of driver and bicyclist roadway design preferences in the San Francisco Bay Area

Two trends in the United States—growth in bicycling and enthusiasm for complete streets—suggest a need to understand how various roadway users view roadway designs meant to accommodate multiple modes. While many studies have examined bicyclists’ roadway design preferences, there has been little investigation into the opinions of non-bicyclists who might bicycle in the future. Additionally, little research has explored the preferences of the motorists who share roads with cyclists—despite the fact that motorists compose the vast majority of roadway users in the United States and similarly developed countries.This paper presents results from an internet survey examining perceived comfort while driving and bicycling on various roadways among 265 non-bicycling drivers, bicycling drivers, and non-driving bicyclists in the San Francisco Bay Area. Analysis of variance tests revealed that both drivers and bicyclists are more comfortable on roadways with separated bicycling facilities than those with shared space. In particular, roadways with barrier-separated bicycle lanes were the most popular among all groups, regardless of bicycling frequency. Striped bicycle lanes, a common treatment in the United States, received mixed reviews: a majority of the sample believed that they benefit cyclists and drivers through predictability and legitimacy on the roadway, but the lanes were rated significantly less comfortable than barrier-separated treatments—particularly among potential bicyclists.These findings corroborate research on bicyclists’ preferences for roadway design and contribute a new understanding of motorists’ preferences. They also support the U.S. Federal Highway Administration’s efforts to encourage greater accommodation of bicyclists on urban streets.

Research on anisotropy of shale oil reservoir based on rock physics model

Rock physics modeling is implemented for shales in the Luojia area of the Zhanhua topographic depression. In the rock physics model, the clay lamination parameter is introduced into the Backus averaging theory for the description of anisotropy related to the preferred alignment of clay particles, and the Chapman multi-scale fracture theory is used to calculate anisotropy relating to the fracture system. In accordance with geological features of shales in the study area, horizontal fractures are regarded as the dominant factor in the prediction of fracture density and anisotropy parameters for the inversion scheme. Results indicate that the horizontal fracture density obtained has good agreement with horizontal permeability measured from cores, and thus confirms the applicability of the proposed rock physics model and inversion method. Fracture density can thus be regarded as an indicator of reservoir permeability. In addition, the anisotropy parameter of the P-wave is higher than that of the S-wave due to the presence of horizontal fractures. Fracture density has an obvious positive correlation with P-wave anisotropy, and the clay content shows a positive correlation with S-wave anisotropy, which fully shows that fracture density has a negative correlation with clay and quartz contents and a positive relation with carbonate contents.

Ex Post Review and Expert Policymaking: When Does Oversight Reduce Accountability?

Ex post review is a common feature of policymaking institutions. We consider a simple environment in which an expert agent makes a policy recommendation, which can then be accepted or rejected by a principal whose policy goals differ from those of the agent. The theory offers testable predictions about policy recommendations and the principal’s acceptance or rejection of these recommendations. The theory suggests that behavior and institutional design incentives are sensitive to both actors’ preference alignment and the importance of and uncertainty inherent to the policy area in multiple ways, some expected and some less obvious. We characterize the types of situations in which ex post review creates incentives for the agent to make pathological policy choices. In these situations, ex post review can reduce the accountability of the agent to the wishes of the principal and ultimately create an incentive for the principal to forego review entirely.

Development of Bi2Te2.4Se0.6 alloy for thermoelectric power generation applications

The quest for improving eco-friendly renewable energy conversion methods due to the declining resources of conventional energy reserves and a rise in environmental awareness is constantly growing. The thermoelectric method of directly converting thermal into electrical energy is attracting increased attention for such applications and thus enhancing its efficiency is of great importance. The most efficient n-type thermoelectric materials for temperatures up to 300 °C are currently Bi2TexSe3-x based. By optimizing the preparation process while considering the inherent crystallographic anisotropy, the efficiency of such materials can be further improved. In this study the Bi2Te2.4Se0.6 composition was optimized by CHI3 doping, preferred alignment of the crystallographic orientation, and lattice thermal conductivity minimization. The synthesis route included rocking furnace melting, energetic ball milling and hot pressing with optimal parameters for enhancement of the thermoelectric figure of merit, ZT, at temperatures higher than 200 °C, commonly applied in low temperature power generation applications. The transport properties in the directions parallel and perpendicular to the pressing direction were examined. In the direction perpendicular to the pressing axis, a maximal ZT of ∼0.9 was obtained at ∼175 °C, which is as far as we know among the highest ever reported for n-type Bi2TexSe3-x based alloys.

Defaults in Green Electricity Markets: Preference Match Not Guaranteed

Green electricity defaults should steer individual choices to environmentally friendly alternatives and provide a match with individuals’ preferences for an electricity mix. It is debatable whether green electricity defaults conform to this latter intention. Using two design elements from existing electricity markets, costly opt-out of contracts and green electricity certificates, preferences for an electricity mix are elicited in an incentivized laboratory experiment. This study then assesses whether preferences in the absence of default options match with preferences in the presence of default options. It turns out that the alignment of default intentions and preferences depends on the relative price for green electricity. Green electricity defaults at low price premia, as currently applied in several electricity markets, do not match subjects’ preferences. The findings are relevant for the design of green electricity defaults. (author's abstract)

(941) - Integration of Palliative Care in End of Life Care for Patients on Durable Mechanical Circulatory Support

Although outcomes for patients on durable ventricular assist device therapy (VAD) continue to improve, patients are still plagued with frequent hospitalizations and limited long-term survival. Little data exists on the optimal timing of and setting for palliative care involvement for these patients. We conducted a retrospective chart review of our single center’s experience to understand how and where VAD patients die. Charts for all patients who died after receiving a durable VAD between August 2008 and January 2015 were reviewed. Only patients who survived index hospitalization and subsequently died on VAD support were included for analysis. Data on demographic, VAD implant data, medical complications, and palliative care utilization were abstracted retrospectively. A total of 62 patients died following VAD implant for either bridge to transplantation (BTT) (49 (79%)) or destination therapy (DT) (13(21%)). Of those, 37 (60%) patients died during the index hospitalization and 25 (40%) patients survived the index hospitalization but ultimately died on VAD support (BTT 66%, DT 34%). Their mean age at time of implant was 59.0 (SD 11.6) years and 84% were male. These patients lived an average of 15.6 (SD 12.4) months on VAD support. Inpatient palliative care team consultation occurred for 12 (48%) of patients at an average of 23.6 (SD 65.3) days prior to death. Causes of death were identified as intracranial bleeding (8 (32%)); pump complications (5 (20%)); sepsis (4 (16%)); multi-organ system failure (3 (12%)), respiratory failure (2 (8%)) and unknown (3 (12%)). Deaths were thought to be sudden, or unexpected, in 14 (56%) patients. Sixteen (64%) patients died in the hospital, 5 (20%) died at home and 4 (16%) died in inpatient hospice. The majority of VAD patients die in hospital settings, but many die at home, and die suddenly. Although palliative care consultation occurred in nearly half of these patients with durable VAD, palliative care was consulted months after VAD implant and near the end of life. There is ongoing need for earlier involvement of palliative care for this population, particularly in the outpatient setting, as a way to improve advanced care planning, symptom management, alignment of treatment preferences with treatments received, as well as caregiver bereavement.