Search

In 1904, Edmond Desbonnet launched La Culture Physique, a magazine that presented itself as scientific and entertaining in its promotion of strength athletes. La Culture Physique prioritized photomechanical imagery to demonstrate the visual merits of the conditioned human body. A surprising number of women feature in nearly each month's issue. The magazine represented these athletes using a number of editing techniques that made their bodies seem remarkably muscular and yet conventionally feminine. But the specific formal qualities of the publication—such as paper quality, printing technology, and size—helped mask the work that went into making its subjects appear real. La Culture Physique is one of very few extant sources wherein the muscularity of specific women is promoted alongside men's during a period when gender disparity was deeply engrained in French society. La Culture Physique worked within and at times pushed against dominant French cultural values articulated around concepts of gender and belonging, using a set of tools that packaged its contents and form as works of art: as legible, desirable, and collectable. This paper demonstrates that these same tools also helped the publication maintain its veneer of authority. La Culture Physique has yet to be examined from an art historical perspective. This paper seeks to remedy this by arguing that La Culture Physique's 1904 issues are a crucial source of historical and visual documentation for scholars interested in how women participated and were represented in early French physical culture. [ABSTRACT FROM AUTHOR]

This article proposes to investigate how the reproduction of images impacted the conditions for the dissemination of scientific knowledge, based on strategies of representation and visual communication. As historical techniques of image reproduction, it is understood here the manual engraving of the matrix (i.e., xylography, chalcography and lithography) that preceded the photomechanical processes until the end of the 19th century. As a case study, the research was conducted by visual representations of the bird-of-paradise - an exotic bird, originating from islands in Southeast Asia, inaccessible to Europe at the time - addressing how it makes itself known to a wider audience, through printed images. Questions related to the modes of visual representation and graphic techniques will be addressed as fundamental attributes for understanding the theme, discussing their different languages, characteristics, limitations and potentialities for the domain and acquisition of knowledge mediated by information design. [ABSTRACT FROM AUTHOR]

Copyright of Umsatzsteuer-Rundschau is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The significance here derives from the challenge of obtaining cartography with details that make possible multiple uses, among which there are: logistics support, scientific research, and rescue operations planning, to name some examples. The older analogue methodologies, such as photo-mechanical processes, involving tracing with wax-coated sheets, have come to be replaced by GIS technology, in which completely different resources are used; these include digital terrain models, also panchromatic or multi-spectral satellite images. These resources, used together,make it possible to create cartography in extreme areas within antarctic territory claimed as Chilean, by means of a compilation of data at officebased workshops. [ABSTRACT FROM AUTHOR]

In the late 1980s, the commercialization of digital reproduction technology led copy art in a new direction, ushering in a new era of events with global impact and significance. Among these events was the second International Electrography and Copy Art Biennial, held in Valencia, Spain, in October 1988, which commemorated the 50th anniversary of the first electrophotographic copy. This landmark occasion marked the beginning of a new and prosperous digital era that would continue throughout the following decade and was spearheaded by artists of the so-called third generation. [ABSTRACT FROM AUTHOR]

The article is an imprint of the journal "GesR: Gesundheitsrecht" (Health Law). It contains information about the publisher Dr. Otto Schmidt KG, the editor RA Prof. Dr. Martin Rehborn and RA Dr. Rudolf Ratzel, the editorial staff, production, advertising, sales, and printing of the journal. It also provides information about subscriptions, subscription prices, and copyright and publishing rights. Additionally, three advantages of the subscription are mentioned, as well as information about a commentary on the Supply Chain Due Diligence Act and the online library of Otto Schmidt. [Extracted from the article]

This article considers the daguerreotype and electricity as the key driving forces in the early histories of photography and photomechanical reproduction. Drawing on three examples – daguerreotype electrotypes, galvanically etched daguerreotypes and the etching process developed by Hippolyte Fizeau – the article aims to demonstrate how closely they were connected and how much interest they raised among scientists and photographers in the early 1840s, particularly in France, Britain and the German-speaking countries. The article shows in what ways the three processes were employed and who developed and used them, which institutions and learned societies were involved in their progress and which theoretical concepts and discussions they gave rise to. Although all three were only short-lived technologies and were largely forgotten by the end of the 1850s, they are more than mere curiosities, as they contribute significantly to our better understanding of the earliest histories of photography and photomechanical reproduction. [ABSTRACT FROM AUTHOR]

This study presents the preparation of porous silicon (PS) using the photoetching technique. The light source was a laser with a 405 nm wavelength. Hydrofluoric acid, hydrogen peroxide, and ethanol were used in the process. An approach to forming PS in a selected area was also studied, in which a computational control of the laser movement was developed. A laser allows for the formation of PS in short period of time using n-type crystalline silicon (c-Si) as a substrate. Photosynthesized PS shows similar characteristics (physical and chemical) to anodized PS. Raman scattering showed a broadening of the peak centered at 525 cm−1, this behavior is related to the formation of PS. Micro-Fourier transform infrared spectroscopy showed bands related to Si-H wagging and SiH2 bending vibrations, these types of bonds were generated during the porosification process. The morphologic characteristics were defined by scanning electron microscopy (SEM) and revealed that the porous structures depend on the potency of the laser used. The topography of the surface confirms PS formation. SEM analysis demonstrated that pores with diameters of 60 and 300 nm can be obtained. Energy-dispersive x-ray spectroscopy showed an increase in oxygen in the PS due to the oxidation process following photoetching. The x-ray diffraction showed that this type of etching eliminates the induced tension in the c-Si grain edges due to PS formation. [ABSTRACT FROM AUTHOR]

In the present work, we use an open-photoacoustic-cell (OPC) operating at high frequency to measure thermal properties of two-layer system samples. Photothermal deflection technique is also employed to measure the samples. The effective thermal diffusivity measured using the OPC method is interpreted using the concept of effective thermal resistance for a series two-layer system. The results show the reliability of the photoacoustic method for a complete thermal characterization of the samples. In addition, by varying the sample effective thickness, the thermal diffusivity and conductivity of each layer are precisely determined. The effective thermal diffusivity, thermal conductivity, and specific heat of a porous catalyst layer (thickness varying from 13 to 53 μm) deposited on an aluminum foil (53 μm in thickness) were thus measured and found to be (3.7±0.3)×10-3 cm2/s, (7.5±0.7)×10-3 W/cm K, and (1.6±0.2) J/gK, respectively. [ABSTRACT FROM AUTHOR]

We have fabricated a microarray of porous silicon Bragg reflectors on a crystalline silicon substrate using a technological process based on standard photolithography and electrochemical anodization of the silicon. The array density is of 170 elements/cm2 and each element has a diameter of 200 μm. The porous silicon structures have been used as platform to immobilize an amino terminated DNA single strand probe. All fabrication steps have been monitored by spectroscopic reflectometry, optical and electron microscopy, and Fourier transform infrared spectroscopy. A label-free detection method has been employed to investigate the hybridization between micromolar DNA probe and its complementary target. Due to fast and low cost production, good reproducibility, and high quality optical features, this platform could be adopted also for other different microarray applications such as proteomics and medical diagnostics. [ABSTRACT FROM AUTHOR]

We present a detailed study of room-temperature current–voltage characteristics of Al–Al2O3–Ag junctions in which the Al electrode was treated by photolithography processing and chemical etching prior to the Al2O3 layer growth. The I–V curves exhibit polarity-dependent irreversible conductance changes and regions of negative differential resistance. These phenomena take place only if the bias voltage exceeds 0.8 V. We discuss a qualitative mechanism for such behavior based on charge accumulation in traps present in the barrier, due to the chemical treatment. [ABSTRACT FROM AUTHOR]

Photogalvanic effect produces actuation of periodic motion of macroscopic LiNbO3 crystal. This effect was applied to the development of an all-optical moving-grating interferometer usable for optical trapping and transport of algae chlorella microorganisms diluted in water with a concentration of 27×104 ml-1. [ABSTRACT FROM AUTHOR]

Because techniques such as photolithography for inorganic materials are yet to have their equivalents for organic materials, multispecies patterning of functional organic materials at microscale resolution remains in development. This paper reports on a liquid droplet transfer printing method, that is, used for microscale patterning of multispecies materials. A transfer printing instrument is built with a multidimensional micropositioning stage, thereby enabling the technique to be used to pattern different materials on a single surface. The size range of the transferred liquid droplets can be tuned by manipulating the surface wettability and the gap between the surfaces of the sample and the stamp. The developed technique is used to prepare red–green–blue pixel patterns and microlenses integrated with color filters. [ABSTRACT FROM AUTHOR]

Abstract As a novel photomechanical behavior, structural changes of azobenzene-based photochromic amorphous molecular films fabricated on the surface of soft materials such as agar gel were found upon irradiation with linearly polarized laser beam. The present photomechanical behavior included two-stage processes, striped pattern formation in the direction perpendicular to the polarization direction of the incident beam and subsequent band-like structure formation aligned in the direction parallel to the polarization direction. Both glass-transition temperature of the photochromic materials and the viscosity of the underlying layers were suggested to be important factors for exhibiting the present photomechanical behavior. Graphical abstract As a novel photomechanical behavior, structural changes with two-stage processes were found for azobenzene-based photochromic amorphous molecular films fabricated on the surface of agar gel. Image 1 Highlights • A photochromic molecular film on agar gel exhibited photomechanical behavior. • The behavior included two-stage processes depending on the polarization direction. • Glass-transition temperature and viscosity were suggested to be important factors. [ABSTRACT FROM AUTHOR]

This paper describes a simple and inexpensive apparatus for measuring the light-induced shape change of a material, which can be implemented in a high school or undergraduate laboratory. The key components of the apparatus are a laser pointer to actuate the material, a force sensor from an inexpensive jeweler's balance to measure the response, an Arduino for data acquisition, and a means for mechanically mounting the setup. The apparatus described here was used by high school students and teachers in a summer program to characterize liquid crystal elastomer samples. The theory of photomechanical response is used to interpret the gathered data, from which material parameters related to this theory are determined. [ABSTRACT FROM AUTHOR]

The article offers information on sculptor Medardo Rosso and the photomechanical reproductions of his works at the start of the 20th century. Topics discussed include the visual historiography of art in the 20th century; the comparison of Rosso's works with the works of Auguste Rodin; and the use of casting by Rosso. Also mentioned are the sculptures Aetas Aurea and Ecce Puer by Rosso.

Graphical abstract Available information on cocrystals containing Schiff bases coordinated to metal atoms is reviewed, with emphasis given to coordination aspects. Abstract Cocrystals are materials that contain molecules of two or more compounds in a single crystal. They have been receiving applications in many fields, including paper, textile, chemical, photographic and electronic industries. However, their main uses are centered in the pharmaceutical industry, where they have been gaining importance in recent years. In this article, the scientific literature reporting structures and properties of cocrystals containing Schiff bases coordinated to metal atoms is reviewed, with emphasis given to the coordination aspects. Schiff bases are the nitrogen analogues of aldehydes or ketones in which the carbonyl group has been replaced by an imine group. They receive multiple uses, e.g., as pigments and dyes, intermediates in organic synthesis, catalysts and polymer stabilizers, and exhibit a broad range of biological activities. Cocrystallization of Schiff bases with other bioactive molecules, and their coordination with metal atoms (which per se may be relevant in terms of biological functions), then appears as a very promising strategy to produce materials of interest for a wide range of applications in pharmaceutical industry. The present review aims to highlight the available relevant information on this type of materials to those interested to work in this domain and stimulate further investigation in the field. [ABSTRACT FROM AUTHOR]

Abstract We propose a scale-bridging methodology to link the microscopic photoreaction of an azobenzene-containing liquid crystalline polymer (LCP) and the macroscopic interfacial and elastic properties of carbon nanotube (CNT)-reinforced photo-responsive nanocomposites. The photo-isomerization of the azobenzene moieties is described by implementing a photo-switching potential that represents the light-excited energy transition path. The relevant time evolution of the molecular shape and the concurrent changes in the interfacial morphology are observed using molecular dynamics (MD) simulations. Finally, the effective elastic properties of the photo-responsive polymer (PRP) nanocomposite with respect to the isomerization ratio are numerically derived using the micromechanics-based homogenization method. It is verified that the size of the CNT and the photo-deformation of the azobenzene molecules influence the intermolecular interactions and the nematic phase of the LCP at the interfacial region. The continuum-scale finite element (FE) model, which reflects the microscopic information, clearly predicts the reinforcing effect of the CNT filler on the elastic properties of the composite and their variation under photo-actuation. We expect our results to shed light on designing the photomechanical energy conversion efficiency of nano-sized soft actuators composed of CNT-reinforced composites. [ABSTRACT FROM AUTHOR]

Abstract: A surfactant‐assisted seeded‐growth method is used to form single‐crystal platelets composed of 9‐methylanthracene with two different internal molecular orientations. The more stable form exhibits a photoinduced twisting, as observed previously for 9‐methylanthracene microribbons grown by the floating drop method. However, the newly discovered elongated hexagonal platelets undergo a photoinduced rolling‐up and unrolling. The ability of the rolled‐up cylindrical shape to trap superparamagnetic nanoparticles enables it to be carried along in a magnetic field gradient. The new photoinduced shape change, made possible by a novel surfactant‐assisted crystal growth method, opens up the possibility of using light to modulate the crystal translational motion. [ABSTRACT FROM AUTHOR]

The design of the adaptive mechanical behavior of polymer nanocomposites driven by light irradiation has attracted considerable attention in the fields of physical chemistry and mechanical engineering. To assess the photo-mechanical properties of photo-responsive polymer (PRP) nanocomposites reinforced with gold nanoparticles via continuum mechanics, we first investigated interfacial properties of PRP nanocomposites by using a novel multiscale multiphysical model. Particularly, the interfacial interactions between the nanoparticle and polymer matrix under external loading were addressed by combining all-atom molecular dynamics (MD) simulations with finite element (FE) analysis. To explicitly characterize the role of the interfacial interactions between the nanoparticle and polymer matrix in strain energy density under photo-mechanical loading, the effective stiffness and the spatial range of the interphase layer were numerically identified by matching the deformation energy in the FE model with that in the MD model using the energy method and the homogenization theory. It is verified that the equivalent continuum model obtained by the multiscale method satisfactorily predicts not only the overall mechanical properties of nanocomposites, but also the local stress distribution at the interphase as well as the inherent nanoparticle size and photo-isomerization reaction effects of the nanocomposites. The present multiscale analysis reveals that the effective interfacial region around the nanoparticle is considerably weakened as the photo-isomerization reaction progresses, as well as the decrease of the thickness of the interfacial region. [ABSTRACT FROM AUTHOR]

ABSTRACT: Liquid crystals are widely employed as stimuli‐responsive materials. Liquid crystallinity can be retained in polymeric form. Photoinduced mechanical effects in liquid crystalline polymer networks and elastomers have been a topic of considerable recent research. This review details the historical underpinnings and recent advances in the synthesis and the corresponding photomechanical response of these materials. In nearly all cases, the conversion of light into mechanical work has employed azobenzene as either a guest additive or covalently attached to the network. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 695–705 [ABSTRACT FROM AUTHOR]

Photomechanical molecular crystals have been investigated as mesoscopic photoactuators. Here, we report how the photomechanical twisting of 1,2-bis(2-methyl-5-phenyl-3-thienyl)perfluorocyclopentene (1a) crystals depends on illumination direction. The ribbon-like crystal of 1a could be successfully prepared by a sublimation method. The ribbon crystal exhibited reversible photomechanical crystal twisting upon alternating irradiation with ultraviolet (UV) and visible light. Moreover, changing the UV illumination direction with respect to the crystal resulted in different twisting modes, ranging from helicoid to cylindrical. Control of photomechanical crystal deformation by illumination direction provides a convenient and useful way to generate a variety of photomechanical motions from a single crystal. [ABSTRACT FROM AUTHOR]

We present a wafer-scale array of resonant coaxial nanoapertures as a practical platform for surface-enhanced infrared absorption spectroscopy (SEIRA). Coaxial nanoapertures with sub-10 nm gaps are fabricated via photolithography, atomic layer deposition of a sacrificial Al2O3 layer to define the nanogaps, and planarization via glancing-angle ion milling. At the zeroth-order Fabry-Pérot resonance condition, our coaxial apertures act as a “zero-mode resonator (ZMR)”, efficiently funneling as much as 34% of incident infrared (IR) light along 10 nm annular gaps. After removing Al2O3 in the gaps and inserting silk protein, we can couple the intense optical fields of the annular nanogap into the vibrational modes of protein molecules. From 7 nm gap ZMR devices coated with a 5 nm thick silk protein film, we observe high-contrast IR absorbance signals drastically suppressing 58% of the transmitted light and infer a strong IR absorption enhancement factor of 104∼105. These single nanometer gap ZMR devices can be mass-produced via batch processing and offer promising routes for broad applications of SEIRA. [ABSTRACT FROM AUTHOR]

Dimethyl-2(3-anthracen-9-yl)allylidene)malonate (DMAAM) is a divinylanthracene derivative that photoisomerizes between its (E) and (Z) conformations. Crystalline nanowires composed of this molecule undergo a rapid coiling motion when exposed to visible light. In this paper, a variety of experimental techniques are used to investigate the mechanism of this transformation, including powder X-ray diffraction, polarized light microscopy, 1H NMR, and absorption spectroscopy. The results show that the presence of a surfactant like cetyltrimethylammonium bromide (CTAB) accelerates the photochemical reaction rate by at least a factor of 10 within the nanowire and is required to observe the photoinduced coiling. The accelerated reaction facilitates the transition to an amorphous phase composed of reactant and photoproduct, which leads to the rapid, large-scale shape changes that the nanowires undergo. Disruption of the highly packed crystal structure by photoisomerization also enhances the dissolution rate by a factor of about 30. The fact that the nanowires have a nominal diameter of 200 nm suggests that the presence of surface species can influence the reaction dynamics deep inside the crystal. These results show that the reaction dynamics and photomechanical motions of nanoscale molecular crystals can be extremely sensitive to surface species. [ABSTRACT FROM AUTHOR]

The aliphatic spacer length connected to the rigid mesogenic cores is shown to control the structural organization and mechanical actuation in response to light-stimulus in azobenzene-functionalized liquid crystalline polymers networks. The spacer lengths in the mesogenic host (non-photochromic) and in the photo-active azobenzene-functionalized cross linker are parametrically varied to create monodomain liquid crystalline samples. A suite of thermomechanical, photomechanical and structural characterization is used to characterize the binary co-polymers. The photomechanical responses are compared by calculating a figure-of-merit – Photocompliance (Cp). This parameter, Cp, which characterizes the incremental strain generated in response to unit intensity of irradiation (W/cm 2 ), is found to correlate strongly with the S xray order parameter and the D-spacings. We show that compact (smaller D) and higher ordering of the mesogens that result in copolymers with longer flexible spacers manifest greater photomechanical activity. [ABSTRACT FROM AUTHOR]

The accumulation of photoinduced deformation in azobenzene functionalized polymers has received a significant amount of attention in recent years. Critically, the induced photomechanical deformation in these systems experiences varying degrees of relaxation. Control over the persistence of photomechanical strains is vital to the broader utility of these materials in shape programmable systems including soft robotics and engineered origami. Furthermore, investigations of relaxation in light responsive polymer systems triggered by UV light are more prominent than those triggered by blue-green light. In this study, the impact of chain mobility and initially induced photostrain on the relaxation dynamics of azobenzene-functionalized polyimides after irradiation with blue light is examined. A modeling effort coupling chromophore population dynamics to material strain is carried out to further explore the relationship between material structure, relaxation dynamics, and macroscopic deformation. The implications for controlling strain persistence are highlighted by simulating one example of a photoprimed bistable actuator. [ABSTRACT FROM AUTHOR]

A micro-resonator based on porous silicon ridge waveguides is implemented by a large scale standard photolithography process to obtain a low cost and sensitive sensor based on volume detection principle instead of the evanescent one usually used. The porous nature of the ridge waveguides allows the target molecules to be infiltrated in the core and to be detected by direct interaction with the propagated light. Racetrack resonator with radius of 100 μm and a coupling length of 70 μm is optically characterized for the volume detection of different concentrations of glucose. A high sensitivity of 560 nm/RIU is reached with only one micro-resonator and a limit of detection of 8.10 −5 RIU, equivalent to a glucose concentration of 0.7 g/L, is obtained. [ABSTRACT FROM AUTHOR]

Indirect nanosecond-pulsed laser ablation of Au film of 10 nm-600 nm has been performed to investigate the ablated surface morphology of Au film as compared to direct pulsed laser ablation. This work shows that both the direct and indirect ablations give similar trend of ablation threshold fluence for film thickness equal or less than 170 nm. In this region, the ablation mechanism is driven by melting and vaporization. However, for film thickness greater than 170 nm, indirect ablation exhibits superior film quality with 3.0-3.6 factors less applied laser fluence compared to direct ablation and thus has no heat-affected zone and no recast material. As a result, the ablation mechanism for indirect ablation is driven by photomechanical process. This work highlighted the significant role of irradiation orientation (direct and indirect) as well as the correlation of heat penetration depth with different Au film thickness in influencing the ablation mechanism of Au film on glass substrate. [ABSTRACT FROM AUTHOR]

We report interesting photomechanical behaviors of the dynamic molecular crystals of (E)-2-(2,4-dichlorostyryl)benzo[d]oxazole (BOACl24). The photosalient effect of the rod-like crystal based on a metal-free olefin driven by photodimerization is observed. Moreover, the needle-like crystals of BOACl24 exhibit a reversible bending away from a UV light source. The nanofibers curl easily under UV irradiation in an organogel, in which the photo-induced rolling of a small slice occurs. This suggests that the rapid release of the accumulated strain during photodimerization may lead to a photosalient effect, and the bending or curling happens when the strain is released slowly. Notably, [2+2] cycloaddition takes place between two different conformational isomers of BOACl24 on account of the rotation of the benzoxazole ring around the C−C bond in an excited state before photodimerization. Such topo-photochemical reaction has not been reported elsewhere. [ABSTRACT FROM AUTHOR]

In this letter, we present a study of the condensation of exciton-polaritons in large etched pillar structures that exhibit shallow edge trapping. The ≈100 µm 100 x µm pillars were fabricated using photolithography and a BCl3/Cl2 reactive ion etch. A low energy region emerged along the etched edge, with the minima ≈7 µm from the outer edge. The depth of the trap was 0.5-1.5meV relative to the level central region, with the deepest trapping at the corners. We were able to produce a Bose-Einstein condensate in the trap near the edges and corners by pumping non-resonantly in the middle of the pillar. This condensate began as a set of disconnected condensates at various points along the edges but then became a single mono-energetic condensate as the polariton density was increased. Similar edge traps could be used to produce shallow 1D traps along edges or other more complex traps using various etch geometries and scales. [ABSTRACT FROM AUTHOR]

Gratings have been widely accepted as practical and effective deformation carriers/sensors and are commonly used in many deformation measurement methods. Since the deformation measurement sensitivity is directly proportional to the grating frequency, and the measurement accuracy is strongly affected by the grating quality. Thus, it is crucial to prepare an appropriate grating on the specimen surface that is to be measured. Over the past few decades, an increasing number of grating fabrication methods have been developed, including holographic photolithography, electron beam lithography, focused ion beam etching, nanoimprinting, soft lithography, and others. Although substantial literature regarding grating fabrication can be found, a comprehensive review is still necessary to promote the application of these methods. This review introduces the technical details and characteristics of recently developed grating fabrication methods and provides suggestions of which grating fabrication methods to use in correspondence with different deformation measurement methods. Emphasis is placed on the introduction of grating fabrication processes and the quality and applicability of the resulting gratings. [ABSTRACT FROM AUTHOR]

In the present paper, we put forward some experimental results on the local thermomechanical behavior of a wet PA6.6 matrix subjected to cyclic loading. We used photomechanical techniques to assess the creep and cyclic strain rate fields, as well as the associated dissipation and coupling heat source fields. This thermomechanical analysis enabled us, from the very beginning of the cyclic test, to track the onset of strain concentration zones and note their limited development. Moreover, this analysis helped us to highlight the co-existence of glassy, rubber and mixed thermal responses. This revealed that wet PA6.6 was a graded material whose property variations surely promoted the development of strain concentration zones. [ABSTRACT FROM AUTHOR]

In this paper, we propose a metaheuristic for solving an original scheduling problem with auxiliary resources in a photolithography workshop of a semiconductor plant. The photolithography workshop is often a bottleneck, and improving scheduling decisions in this workshop can help to improve indicators of the whole plant. Two optimization criteria are separately considered: the weighted flow time (to minimize) and the number of products that are processed (to maximize). After stating the problem and giving some properties on the solution space, we show how these properties help us to efficiently solve the problem with the proposed memetic algorithm, which has been implemented and tested on large generated instances. Numerical experiments show that good solutions are obtained within a reasonable computational time. [ABSTRACT FROM AUTHOR]

L’Illustration and Le Monde illustré, Parisian up-market general-interest weekly illustrated magazines of the Illustrated London News genre published long Salon reviews every year there was a Salon. They also reproduced numbers of Salon pictures each year, in fluctuating (often very large) numbers, in a range of reproductive technologies, and accompanied by textual and presentational clues about what sorts of value the magazine was inviting its reader/viewers to attach to the reproduction: to the painting represented also but in the first instance to the reproduction. Engaging with recent work by Stephen Bann, this article discusses the ways in which, in these magazines, reproductive wood engravings were aligned with the great tradition of French reproductive intaglio printmaking, and it looks at the impact of the introduction of photomechanical technologies (the line block and the half-tone screen) on the values that were attached to these pictures of Salon pictures. It demonstrates the persistence into the 1890s of the value system of reproductive engraving, and its eventual displacement by the more mechanical efficiencies of the half-tone screened photograph of a work of art. The essay calibrates this displacement with the increasingly compelling demands of the news cycle in relation to the visual reporting of the Salon, and it provides evidence that the half-tone screen, for a decade after its introduction, was a less-than-adequate technology for the reproduction of photographs of works of art, as the evidence of its uptake in the more technologically progressive of these two titles, L’Illustration, demonstrates. The essay also engages with the debate over ‘the end of the Salon’ (Mainardi). From the evidence of the resources that these magazines devoted not only to writing about but also to reproducing pictures from, the Salon through from the 1860s to the end of the 1890s, the essay argues that, at last for the national bourgeois audience that was constituted by the wide readership of these two magazines, reports of the Salon’s death have been greatly exaggerated. [ABSTRACT FROM AUTHOR]

The photomechanical motion of chiral crystals of trans-azobenzene derivatives with an (S)- and (R)-phenylethylamide group was investigated and compared with a racemic crystal. Changes in the UV/Vis absorption spectra of the powdered crystals before and after UV irradiation were measured by using an optical waveguide spectrometer, showing that the lifetime of the cis-to-trans thermal back-isomerization of the chiral crystals was faster than that of the racemic crystals. Upon UV irradiation, a long plate-like chiral microcrystal bent away from the light source with a twisting motion. A square-like chiral microcrystal curled toward the light with some twisting. Reversible bending of a rod-like chiral microcrystal was repeatable over twenty-five cycles. In contrast, bending of a plate-like racemic microcrystal was small. A possible mechanism for the bending and twisting motion was discussed based on the optimized cis conformer determined by using calculations, showing that the bending motion with twisting is caused by elongation along the b axis and shrinkage along the a axis. [ABSTRACT FROM AUTHOR]

The effect of ultraviolet light produced ozone and irradiation (UV/ozone) cleaning on the surface properties and interface electrical properties of 4 unit cell (uc) LaAlO3/SrTiO3 samples is examined. A standard photolithography process is used to contaminate the samples which are then cleaned in UV/ozone. Atomic force microscopy measurements show that the photoresist contaminated samples can be cleaned efficiently using this method. The surface roughness of the cleaned samples is comparable to that of the as-grown samples. Furthermore, electrical transport measurements show that the mobility decreases and the sheet carrier density increases for the contaminated samples, which also display indications of an onset to the Kondo effect. By removing the contaminants with UV/ozone cleaning, the mobility and sheet carrier density can be partially restored toward the as-grown values. The mobility is increased by about two times from ≈1000 cm² V-1 s-1 for the contaminated samples to ≈2000 cm² V-1 s-1 for the ozone cleaned ones. [ABSTRACT FROM AUTHOR]

Bio-compatible actuators which can work under optical stimulus have great future in bio-medical applications. In this work, chitosan/reduced graphene oxide (RGO) nanocomposite optical actuators were developed through a simple solvent casting technique. The photomechanical actuation of the composites is demonstrated under IR illumination. All samples exhibited contraction in length when exposed to IR light. The photomechanical stress and strain were found to increase with increasing RGO concentration. Photomechanical stress as high as 695 kPa was achieved with 4 wt.% RGO loading. Contrary to some other reported systems, the photomechanical stress decreased with the applied pre-strain. The actuation behaviour can be tuned either by altering the RGO content or applied pre-strain. [ABSTRACT FROM AUTHOR]

The photomechanical motion of chiral crystals of trans-azobenzene derivatives with an ( S)- and ( R)-phenylethylamide group was investigated and compared with a racemic crystal. Changes in the UV/Vis absorption spectra of the powdered crystals before and after UV irradiation were measured by using an optical waveguide spectrometer, showing that the lifetime of the cis-to- trans thermal back-isomerization of the chiral crystals was faster than that of the racemic crystals. Upon UV irradiation, a long plate-like chiral microcrystal bent away from the light source with a twisting motion. A square-like chiral microcrystal curled toward the light with some twisting. Reversible bending of a rod-like chiral microcrystal was repeatable over twenty-five cycles. In contrast, bending of a plate-like racemic microcrystal was small. A possible mechanism for the bending and twisting motion was discussed based on the optimized cis conformer determined by using calculations, showing that the bending motion with twisting is caused by elongation along the b axis and shrinkage along the a axis. [ABSTRACT FROM AUTHOR]

Photomechanical bilayer actuators, constituted by PDMS/GNPs thin layer and PDMS thin layer, are presented. Due to the photothermal effect of GNPs and differences in CTE of the two layers caused by the GNPs existed in PDMS/GNPs thin layer; the bilayer actuator can display photomechanical bending under nIR light irradiation. And it is interesting to notice that the bilayer actuators show a two-step photomechanical bending process when the nIR light is incident from the PDMS/GNPs thin layer while one-step photomechanical bending process when from the PDMS thin layer, which is different from the process commonly observed in thermal bilayer and bimorph actuators. According to preliminary analysis, it is revealed that the photomechanical two-step bending is the results of temperature gradient effect and thermal bilayer effect, while the one-step photomechanical bending process only caused by thermal bilayer effect. Meanwhile, the photomechanical bendings are both positively correlated with light intensities. By adjusting the rotation speed in spinning coating, various bilayer actuators with different thickness of PDMS thin layer were fabricated and tested. The photomechanical deflections decreased with the augment of rotation speed. In addition, the realization of micromachines with our proposed bilayer actuators was demonstrated. [ABSTRACT FROM AUTHOR]

(E)-3-(Anthracen-9-yl)acrylic acid (9-AYAA) exhibits a strong photomechanical response in bulk crystals but is challenging to grow in microcrystalline form. High quality microcrystals of this molecule could not be grown using techniques like sublimation, reprecipitation, and the floating drop method. If the tertbutyl ester of 9-AYAA is used as a starting material, however, high quality, size-uniform microwires could be grown via acid catalyzed hydrolysis. 9-AYAA microwires with uniform length and thickness were produced after a suspension of (E)-tert-butyl 3-(anthracen-9-yl)acrylate ester microparticles was tumble-mixed in a mixture of phosphoric acid and sodium dodecyl sulfate at 35 °C. The dependence of the results on temperature, surfactant and precursor concentration, and mixing mode was investigated. This chemical reaction-growth method was extended to grow microplates of 9-anthraldehyde using the corresponding acylal as the starting material. Under 475 nm irradiation, the 9-AYAA microwires undergo a photoinduced coiling–uncoiling transition, while the 9-anthraldehyde microplates undergo a folding–unfolding transition. [ABSTRACT FROM AUTHOR]

Purpose – This paper aims to optimize the operating condition of mechanical parts, whose working surfaces have macro-crack defects, and surface wear properties with macro-cracks are assessed through experimental investigation. Design/methodology/approach – Macro-cracks perpendicular to the direction of sliding were manufactured on discs by electric discharge machining. Tribological tests under oil lubrication were conducted on a ball-on-disc test rig. Their wear processes were monitored with on-line visual ferrography. The cross-sectional profile and morphology of the wear track were analyzed using a T200 profilometer and a scanning electron microscope, respectively. Effects of different crack numbers and various applied normal loads on the wear behavior were studied. Findings – The macro-cracks tend to promote plastic deformation on the contact disc surfaces, and material plastic deformation of the crack edges varies with the magnitude of applied normal loads. Relationship of the duration of running-in period and root mean square index of the particle coverage area with the numbers of crack is approximately linear. Originality/value – The wear properties of surfaces with macro-cracks were assessed with various crack numbers and with different applied normal loads, and the relationship between the index of particle coverage area and the wear rate was established. [ABSTRACT FROM AUTHOR]

Azobenzene-containing materials exhibit various photomechanical properties, including the formation of surface relief gratings (SRG) when irradiated with two interfering laser beams. In a recent study, a novel glass-forming derivative of Disperse Red 1 (DR1) with a mexylaminotriazine group was synthesized in high yield with a simple and efficient procedure, and showed the ability to form high-quality amorphous thin films with a high resistance to crystallization. Irradiation of films of this material yielded SRG with growth rates comparable to other reported azo materials. Herein, a series of closely related molecular glasses containing azobenzene chromophores with various absorption maxima ranging from 410 to 570 nm were synthesized, and their physical and photomechanical properties were studied. All materials studied showed the ability to form stable glassy phases, and irradiation with lasers emitting at various wavelengths allowed to perform a comparative study of SRG growth within a series of analogous chromophores. [ABSTRACT FROM AUTHOR]

The increasing number of reports on photomechanical effects in molecular crystals necessitates systematic studies to understand the intrinsic and external effectors that determine and have predictive power of their type and magnitude. Differential light absorption and product gradient between the surface and the bulk of the crystal are often invoked to qualitatively explain the mechanical response of crystals to light; however, the details on how this difference in photochemical response accounts for macroscopic effects such as surface modification, deformation, or disintegration of crystals are yet to be established. Using both bulk- and surface-sensitive analytical techniques, a rare instance of benzylidenefuranone crystals is studied here, and it is capable of several distinct types of photomechanical response including surface striation and delamination, photosalient effect (ballistic disintegration and motion), and photoinduced bending by dimerization. The results provide a holistic view on these effects and set the stage for the development of overarching theoretical models to describe the photomechanics in the ordered solid state. [ABSTRACT FROM AUTHOR]