bluuebunny/crossref_metadata_2025 huggingface dataset:
Anthropocene: Transdisciplinary Shorthand for Human Disruption of the Earth System
Authors: Koster Emlyn
Published: August 2020

Increasingly, deliberations to potentially add the Anthropocene to the Geological Time Scale in recognition of humanity’s environmental impacts and stratigraphic record are attracting interest from non-geological disciplines and the news media. The 35 member Anthropocene Working Group, a constituent body of the International Commission on Stratigraphy, recently concluded that the worldwide fallout of radionuclides from atomic bomb testing in the mid-20th century best defines the base of the Anthropocene. With a search for the optimal ‘golden spike’ locality in progress as a key step toward any ratification by the International Union of Geological Sciences, there are widely held views outside of geological circles that the Anthropocene is already designated as an epoch. Regardless of its eventual formal or informal standing, this article opines that the term Anthropocene has become valuable shorthand for recognizing humanity as the dominant species which, in a geological nanosecond, has extensively detached itself from the Earth System, endangering the future of both. Accordingly, this article urges the entire geological profession to engage with the work of the Anthropocene Working Group and, as the originator of the term, to coalesce its activities with those of other disciplines concerned with environmental health and linked human health challenges.
RÉSUMÉDe plus en plus, les délibérations visant à éventuellement ajouter l'Anthropocène à l'échelle du temps géologique en reconnaissance des impacts environnementaux de l'humanité et des données stratigraphiques suscitent l'intérêt des disciplines non géologiques et des médias. Les 35 membres du Groupe de travail sur l'Anthropocène, un organe constitutif de la Commission internationale de stratigraphie, ont récemment conclu que les retombées mondiales des radionucléides résultant des essais de bombes atomiques au milieu du XXe siècle définissent le mieux la base de l'Anthropocène. Avec la recherche de la localité de référence optimale du « clou d'or » en cours comme étape clé vers toute ratification par l'Union internationale des sciences géologiques, il existe des opinions largement partagées en dehors des cercles géologiques selon lesquelles l'Anthropocène est déjà désigné comme une époque. Indépendamment de sa position finale formelle ou informelle, cet article estime que le terme Anthropocène est devenu un raccourci précieux pour reconnaître l'humanité comme l'espèce dominante qui, dans une nanoseconde géologique, s'est largement dissocié du système terrestre, mettant en danger l'avenir des deux. Par conséquent, cet article exhorte l'ensemble de la profession géologique à s'engager dans les travaux du Groupe de travail sur l'Anthropocène et, en tant que créateur du terme, à fusionner ses activités avec celles d'autres disciplines concernées par la santé environnementale et les défis liés à la santé humaine.
Forced Ecosystems and Digital Stepchildren: Reconfiguring Advertising Suppliers to Realize Disruptive Social Media Technology
Authors: Ozcan Pinar , Hannah Douglas
Published: August 2020

Research often examines disruption in the context of head-to-head competition between firms and technologies. In contrast, we examine the unique dynamics of disruptive technologies within supplier ecosystems. We do so through an inductive multiple case study set in the global advertising industry from 2008–2013, as the industry grappled with the emergence of social media. Using rich archival and field data, we closely track five global consumer goods manufacturers and their associated advertising suppliers as they attempted to integrate social media into their advertising activities. Our primary contribution is to unpack the process by which firms reconfigure their supplier ecosystems to address disruptive new technologies. Our framework reveals that integrating new technologies may require firms to reconfigure the distributions of both activity and power, and that fundamental trade-offs may leave the value of new technologies unrealized. Broadly, we contribute to research and theory on buyer-supplier relationships, alliances, and technology disruption by bringing a more realistic perspective that considers firms’ network of suppliers and interfirm turf wars in technology adoption.
Current advances in lymphoedema management
Authors: Wong Kai Yuen , Furniss Dominic
Published: August 2020

Lymphoedema is the accumulation of protein-rich interstitial fluid within subcutaneous tissue and skin as a result of dysfunction of the lymphatic system. It is an underestimated, widely neglected and debilitating chronic condition. This article presents an overview of lymphoedema and recent advances in its management.
Tibial tuberosity ossification predicts reoperation for growth disturbance in distal femoral physeal fractures
Authors: Kennedy James , Westacott Dan , Camp Mark , Howard Andrew
Published: August 2020

Purpose

Distal femoral physeal fractures (DFPF) can cause growth disturbance that requires further surgical intervention. The aim of this study is to determine if Tibial Tuberosity Ossification Stage (TTOS) at the time of injury predicts secondary surgery for growth disturbance in patients who have sustained a DFPF.

Methods

We retrospectively investigated all patients who had operative treatment for a DFPF at a single centre over a 17-year period. Regression analysis was performed investigating associations between secondary surgery to treat growth disturbance and TTOS, age, Salter-Harris fracture classification type, mode of fixation or mechanism of injury.

Results

In all, 85 consecutive patients were identified. A total of 74 met the inclusion criteria. The mean age at time of injury was 13.1 years (2.0 to 17.1). Following fixation, 30 patients (41%) underwent further surgery to treat growth disturbance. Absence of tibial tuberosity fusion to the metaphysis was significantly associated with the need for further surgery (p < 0.001). Odds of requiring secondary surgery after tibial tuberosity fusion to metaphysis (compared with not fused) were 0.12 (95% confidence interval (CI) 0.04 to 0.34). The estimate of the effect of TTOS on reoperation rates did not vary when adjusted for gender, mechanism, fixation and Salter-Harris type. When accounting for age, the odds of any further operation if the tibial tuberosity is fused to the metaphysis (compared with not fused) were 0.28 (95% CI 0.08 to 0.94).

Conclusion

TTOS at the time of injury is a predictor of further surgery to treat growth disturbance in paediatric distal femoral fractures.

Level of Evidence

Diagnostic Level II
Assessment of Empirical and Semi-Empirical Models for Estimating a Soil Infiltration Function
Authors: Salahou Mohamed Khaled , Jiao Xiyun , Lü Haishen
Published: August 2020

Highlights

The hydraulic performance computed with the KE or GA model is nearly the same, as long the models are calibrated using the same observation data.

The GA model with the soil hydraulic parameters obtained from the pedotransfer functions adequately represented the soil infiltration function.

The particle size distribution or the soil texture are recommended to estimate soil hydraulic parameters with the VG-ROSETTA model.

Abstract. Field-scale estimation of a soil infiltration function is important for the design, simulation, and/or evaluation of surface irrigation systems. Semi-empirical and empirical infiltration models are used to estimate the infiltration function. Semi-empirical infiltration models have substantial computational and parameterization complexities, e.g., soil hydraulic parameters are needed to estimate the infiltration function. In contrast, empirical infiltration models are generally not considered to have specific initial and boundary conditions. The objectives of this study were to compare a semi-empirical infiltration model and an empirical infiltration model. The Green-Ampt model (GA) and the Kostiakov model (KE) were used as semi-empirical and empirical infiltration models, respectively. The soil hydraulic parameters for the GA model were estimated using various pedotransfer functions (PTFs), and in an additional assessment, the measured water content data were used to calibrate and validate the soil hydraulic parameters using the HYDRUS-1D model. The results show that the hydraulic performance computed with the KE or GA model is nearly the same, as long as they are calibrated using the same observation data. Additionally, the results indicate that the GA model with the soil hydraulic parameters obtained from the PTFs adequately represented the soil infiltration function in the borders. Keywords: Empirical infiltration model, Green-Ampt model, Infiltration model, Kostiakov model, Semi-empirical infiltration model, Soil hydraulic properties.
Model Maintenance of RC-PLSR for Moisture Content Measurement of Dried Scallop
Authors: Huang Hui , Liu Shuchang , Ullah Junaid , Sun Zehao , Liu Caicai , Zhang Zhao , Wang Hangzhou
Published: August 2020

Highlights

The RC-PLSR model for Haiwan scallop can be transferred to Xiayi scallop.

The direct standardization method is suggested for model maintenance.

The VSWS-PDS method can be further improved in precision.

Abstract. A prediction model for evaluating the moisture content in dried Haiwan scallops was established using hyperspectral imaging (HSI) technology in a previously published study. The accuracy of such models is usually affected by differences in sample species, different environmental conditions such as temperature or humidity, and aging of instruments. In this study, the prediction ability of the RC-PLSR model is improved by correcting the spectra of the tested species of dried scallop (i.e., Xiayi) to solve the problem of model failure caused by sample differences. The results of model maintenance by direct standardization (DS) are compared with those of variety sensitive wavelength selection - piecewise direct standardization (VSWS-PDS). The results showed that after using VSWS-PDS to modify the spectral data of the dried scallop samples, the correlation coefficient of prediction (Rp) of the updated model increased from 0.0890 to 0.9190. However, the root mean square error of prediction (RMSEP) also increased, indicating a need for improved precision. The RC-PLSR model based on DS correction showed Rp of 0.790 and RMSEP of 9.7481%. Model maintenance using the DS method is suggested because DS generally outperformed VSWS-PDS, even with a lower correlation coefficient. Future work on error reduction and sample input is suggested for VSWS-PDS optimization. Keywords: Direct standardization, Hyperspectral images, Model maintenance, Scallop, VSWS-PDS.
Development of a Robotic End-Effector for Apple Tree Pruning
Authors: Zahid Azlan , He Long , Zeng Lihua , Choi Daeun , Schupp James , Heinemann Paul
Published: August 2020

Highlights

An end-effector with two degrees of freedom (2R) was developed for pruning apple trees.

A rational 2×2 relationship (R2 = 0.93) was found for ‘Fuji’ apple tree branch diameter and cutting force.

Simulation showed that the cutter can be aligned in a wide range of orientations in a spherical workspace.

The developed end-effector was able to cut branches up to 12 mm in diameter.

Abstract. Robotics and automation technologies are now used extensively in agriculture, while production operations for tree fruit crops still largely depend on manual labor. Manual pruning is a labor-intensive and costly task in apple production. Robotic pruning is a potential solution, but it involves several challenges due to the unstructured work environment. This study focused on designing an end-effector prototype for pruning considering the maneuvering, spatial, mechanical, and horticultural requirements. Branch cutting force was measured with a thin force sensor to provide guidelines for the end-effector design. The test results indicated the relationship between the force required to cut different diameter branches with an R2 value of 0.93. The end-effector was developed using two rotary motors, a pneumatic cylinder, and a pair of bypass shear blades. A three-directional linear manipulator system and a control system were built for moving the end-effector to targeted locations. A mathematical model was developed for simulation of the workspace utilization and reachable points of the end-effector. The simulation results indicated that the end-effector can be aligned in a wide range of orientations of the cutter. Field tests were conducted for validation of the simulation results and performance assessment of the end-effector. The results indicated that the end-effector with the current parameter settings successfully cut branches up to 12 mm in diameter and was able to cut branches in a wide range of possible orientations in a given 3D space. The robotic end-effector developed in this study is a core component of an automated pruning system for fruit trees. In future work, an integrated manipulator system will be developed for branch accessibility with collision-free trajectories. Keywords: Malus × domestica (Borkh.), Pruning end-effector, Reachable-points simulation, Tree pruning.
Hardware and Software Design for Premixing In-Line Injection System Attached to Variable-Rate Orchard Sprayer
Authors: Zhang Zhihong , Zhu Heping , Hu Chengsong
Published: August 2020

.

Highlights

A premixing in-line injection system was designed as a retrofit attachment to a laser-guided variable-rate orchard sprayer.

A graphical user interface with touchscreen functions was incorporated into the system to facilitate field applications.

Preliminary tests demonstrated that simulated pesticide and water could be accurately dispensed and discharged separately into the injection line and mixed well in the buffer tank.

This premixing in-line injection system has great potential to further reduce pesticide waste and improve environmental stewardship for conventional and precision variable-rate sprayers.

Abstract To eliminate the problems associated with leftover tank mixture in pesticide applications, a premixing in-line injection system was designed as an attachment to a laser-guided variable-rate orchard sprayer. The primary components of the system consisted of a chemical metering pump, a water pump, a two-stage static mixer, a premixing tank, a buffer tank, an electric shut-off valve, a chemical container, electronic control boards, a graphical user interface, and an embedded computer with a touch screen. Liquid level sensors were mounted in all tanks and the chemical container to control the fluid discharge and prevent overflows. The graphical user interface on the touch screen was designed for operators to communicate with the system and monitor the system status. During spray applications, the system performed with automatic loops in dispensing, mixing, and transferring the desired amounts of water and chemical concentrates to maintain the spray mixture at a constant concentration for use with variable-rate nozzles. The system was rinsed automatically when the spray application task was completed. Test results showed that simulated pesticide and water could be accurately delivered into the injection line and could be mixed well in the buffer tank before the spray mixture was discharged to the nozzles. The premixing in-line injection system is a potential technique to further reduce pesticide waste and improve environmental stewardship for both conventional and precision variable-rate orchard sprayers. Keywords: Automation, Environmental protection, Intelligent sprayer, Pesticide spray application, Precision agriculture, Tank mixture leftover.
Three-beam rotational coherent anti-Stokes Raman spectroscopy thermometry in scattering environments
Authors: Richardson Daniel R. , Kearney Sean P. , Guildenbecher Daniel R.
Published: August 2020

Three-beam rotational coherent anti-Stokes Raman scattering (CARS)
measurements performed in highly scattering environments are
susceptible to contamination by two-beam CARS signals generated by the
pump–probe and Stokes–probe interactions at the measurement volume. If
this occurs, differences in the Raman excitation bandwidth between the
two-beam and three-beam CARS signals can add significant errors to the
spectral analysis. This interference to the best of our knowledge has
not been acknowledged in previous three-beam rotational CARS
experiments, but may introduce measurement errors up to 25% depending
on the temperature, amount of scattering, and differences between the
two-beam and three-beam Raman excitation bandwidths. In this work, the
presence of two-beam CARS signal contamination was experimentally
verified using a femtosecond–picosecond rotational CARS instrument in
two scattering environments: (1) a fireball generated by a
laboratory-scale explosion that contained particulate matter, metal
fragments, and soot, and (2) a flow of air and small liquid droplets.
A polarization scheme is presented to overcome this interference. By
rotating the pump and Stokes polarizations

+

55

∘

and

−

55

∘

from the probe, respectively, the
two-beam and three-beam CARS signals are orthogonally polarized and
can be separated using a polarization analyzer. Using this
polarization arrangement, the Raman-resonant three-beam CARS signal
amplitude is reduced by a factor of 2.3 compared to the case where all
polarizations are parallel. This method is successfully demonstrated
in both scattering environments. A theoretical model is presented, and
the temperature measurement error is studied for different
experimental conditions. The criteria for when this interference may
be present are discussed.
Spectral supralinearity of silicon photodiodes with over-filled illumination in the near-infrared region
Authors: Tanabe Minoru
Published: August 2020

The spectral nonlinearities of silicon (Si) photodiodes (PDs) with over-filled illumination in the near-infrared region were investigated under reverse-bias and zero-bias voltage conditions. The supralinear behaviors and their wavelength dependences were clearly observed with over-filled illumination under both the reverse-bias and zero-bias voltage conditions at the selected wavelengths. Comparing these results with the nonlinearity results obtained in the under-filled illumination condition, it was evident that the maximum supralinearity values observed under the over-filled illumination condition were larger than those in the under-filled illumination condition, and the maximum value (

∼

10

%

) was obtained at the incident wavelength of 1060 nm. To validate the relatively large supralinearity value obtained under the over-filled illumination condition in the near-infrared region, the linearity factor and the photocurrent, as a function of the Si PD positions, and their wavelength dependences were examined under both the reverse-bias and zero-bias voltage conditions at all wavelengths. The linearity factors at the selected wavelengths, under both conditions, exceeded unity at all the PD positions; specifically, the values near the PD electrode were larger than those near the PD center, although the examined photocurrent decreased as the laser beam strayed off the beam detection area of the Si PD. These results highlighted that the relatively large supralinearity was generated under the over-filled illumination condition and that the minority carrier traps for the supralinearity-generating recombinations exist not only near the PD center but also near the PD electrode. These experimental results can facilitate the 3D theoretical modeling of Si-based photodetectors and aid the achievement of high-accuracy measurements with Si PDs in the fields of radiometry and radiation thermometry.
Hollow rectangular multi-Gaussian Schell-model source
Authors: Yuan Caifu , Zheng Simin , Ji Xiaoling , Wang Tao
Published: August 2020

We introduced a new class of a partially coherent source that can generate a field with a hollow rectangular profile, named the hollow rectangular multi-Gaussian Schell-mode source. The dependence of distribution of far-zone spectral density on the properties of the proposed source was analyzed. The results show that one can control the distribution properties of the far-zone intensity profile, including the thickness of the hollow edge, the shape of the hollow, the size of the hollow, and the orientation of the hollow, by adjusting the corresponding structural parameters of the source.
Blackbody far-field coherence
Authors: Al Lakki Mohammad , Setälä Tero , Friberg Ari T.
Published: August 2020

We revisit the spectral coherence properties of far-field radiation emanating from an aperture in a blackbody cavity on the basis of Kirchhoff’s boundary conditions. We point out that the far zone cross-spectral density matrix derived earlier in the literature by separately propagating all three aperture-field components does not show transversality of the field at nonparaxial directions. This is not the case when Luneburg’s diffraction integrals are applied on the transverse source field components to determine the entire far field. We compare the electromagnetic degrees of coherence for the two methods and show that over important angular separations their values coincide with high accuracy. The results of this work and of others concerning the far-field intensity, polarization, and paraxial angular coherence are in full agreement.
Vector wave analysis of Airy beams upon reflection and refraction
Authors: Hui Yuanfei , Cui Zhiwei , Zhao Minhua , Han Yiping
Published: August 2020

As a kind of typical self-accelerating laser beam, Airy beams have attracted much attention due to their fascinating properties and various potential applications. In this work, we carry out a full vector wave analysis of Airy beams upon reflection and refraction. A hybrid method based on the angular spectrum representation and vector potential in the Lorenz gauge is introduced to describe the vectorial structure of Airy beams upon reflection and refraction. The explicit analytical expressions for the electric and magnetic field components of arbitrarily incident Airy beams reflected and refracted at an air-medium interface are derived in detail. Local-field patterns and magnitude profiles with different parameters are displayed. The analytical formulas obtained in this work can be practically applied to explore the local dynamical characteristics, including the energy, momentum, spin, and orbital angular momentum of Airy beams upon reflection and refraction.
Quantum analysis of a traveling-wave electro-optic phase modulator in the presence of the phase noise from a radio frequency oscillator and a laser
Authors: Pratap Rana , Ramachandran Harishankar
Published: August 2020

Quantum analysis has been done for the traveling-wave (TW) electro-optic phase modulator in the presence of the phase noise of a radio frequency (RF) oscillator and a laser source, in which the Hamiltonian for an active section of the phase modulator system is derived. The effect of RF phase noise from the oscillator and a phase velocity mismatch (PVM) between optical photons and the RF field are included in the Hamiltonian. The time evolution of the field operator of the laser in the TW electro-optic phase modulator is derived by the Heisenberg equation of motion. The action of a TW electro-optic phase modulator in the presence of the two distinct weak noises—classical phase noise because of RF and quantum phase noise caused by a laser—has been evaluated and explained in terms of the second-order temporal correlation function and power spectrum. The power spectrum has been written as a function of the semiconductor laser linewidth, an enhancement factor in the laser linewidth, and the RF oscillator linewidth. The results are applied to analyze the basic model of a frequency-coded quantum key distribution (FC-QKD) system. The quantum bit error rate (QBER), the first-order optical intensity correlation function, and the spectrum of intensity fluctuation have been calculated for the partially coherent regime to evaluate the performance of the FC-QKD system.
Free-space quantum secure direct communication based on decoherence-free space
Authors: Gao Zikai , Ma Mingfeng , Liu Tianqi , Long Jiada , Li Tao , Li Zhenhua
Published: August 2020

We propose a free-space quantum secure direct communication protocol by using hyper-encoded single photons. The communication parties can securely exchange private information in a deterministic way. In this protocol, single photons are encoded simultaneously by both the polarization and spatial-mode degrees of freedom that constitute a decoherence-free space. The detrimental effect introduced by either reference-frame misalignment or practical channel rotational noise is passively suppressed. Finally, the security of our protocol against classical individual attacks is proved by quantum mutual information.
Sensitive multi-species trace gas sensor based on a high repetition rate mid-infrared supercontinuum source
Authors: Eslami Jahromi Khalil , Nematollahi Mohammadreza , Pan Qing , Abbas Muhammad Ali , Cristescu Simona M. , Harren Frans J. M. , Khodabakhsh Amir
Published: August 2020

We present a multi-species trace gas sensor based on a high-repetition-rate mid-infrared supercontinuum source, in combination with a 30 m multipass absorption cell, and a scanning grating spectrometer. The output of the spectrometer is demodulated by a digital lock-in amplifier, referenced to the repetition rate of the supercontinuum source. This improved the detection sensitivity of the system by a factor 5, as compared to direct baseband operation. The spectrometer provides a spectral coverage of 950 cm−1 (between 2.85-3.90 µm) with a resolution of 2.5 cm−1 in 100 ms. It can achieve noise equivalent detection limits in the order of 100 ppbv Hz−1/2 for various hydrocarbons, alcohols, and aldehydes.
Nonlinear transition between PT-symmetric and PT-broken modes in coupled fiber lasers
Authors: Suchkov Sergey V. , Churkin Dmitry V. , Sukhorukov Andrey A.
Published: August 2020

We present a systematic analysis of the stationary regimes of nonlinear parity-time (PT) symmetric laser composed of two coupled fiber cavities. We find that power-dependent nonlinear phase shifters broaden regions of existence of both PT-symmetric and PT-broken modes, and can facilitate transitions between modes of different types. We show the existence of non-stationary regimes and demonstrate an ambiguity of the transition process for some of the unstable states. We also identify the presence of higher-order stationary modes, which return to the initial state periodically after a certain number of round-trips.
Quantitative defect analysis in MOCVD GaN-on-GaN using cathodoluminescence
Authors: Chen Zhaoying , Zhang Yuxuan , Zhao Hongping
Published: August 2020

Cathodoluminescence (CL) is used as a quantitative characterization technique to probe impurities at the metal-organic chemical vapor deposition (MOCVD) grown GaN-on-GaN homoepitaxial interfaces. CL intensity contrast shows a strong correlation with the interfacial impurity concentrations. Based on the analysis of recombination mechanisms of electron beam induced non-equilibrium carriers, an analytical model is proposed to quantitatively determine the impurity concentrations from CL intensity. The extracted interfacial impurity concentrations from the analytical model show a good agreement with the compensation levels obtained from capacitance-voltage measurement, signifying the potential of CL for probing the quantitative impurity levels in GaN-on-GaN structures. This approach can also be extended to be applied in other material systems.
Method for monitoring singlet oxygen quantum yield in real time by time resolved spectroscopy measurement
Authors: Liu Ting , Zhang Xiyu , Zhang Honglin , Zhao Hua , Zhang Zhiguo , Tian Ye
Published: August 2020

The singlet oxygen quantum yield (ΦΔ) was monitored in real time through time resolved spectroscopy measurement, using gadolinium labeled hematoporphyrin monomethyl ether (Gd-HMME) as photosensitizer. According to the kinetics equations of singlet oxygen generation and reaction, ΦΔ was related to phosphorescence lifetime (τp). Through measuring τp of Gd-HMME in different oxygen conditions, the radiation transition property of first exited triplet state (T1) was monitored; combined with the triplet state quantum yield (ΦT) determined by linear fitting the ΦΔ, which was measured in different oxygen content using a relative measurement, ΦΔ can be determined in real time. The identification of anoxia during the treatment of photodynamic therapy (PDT) by this method is also presented.
Pupil plane actuated remote focusing for rapid focal depth control
Authors: Cheng Zongyue , Jiang Hehai , Gan Wenbiao , Cui Meng
Published: August 2020

Laser scanning is widely employed in imaging and material processing. Common laser scanners are often fast for 2D transverse scanning. Rapid focal depth control is highly desired in many applications. Although remote focusing has been developed to achieve fast focal depth control, the implementation is limited by the laser damage to the actuator near laser focus. Here, we present a new method named pupil plane actuated remote focusing, which enables sub-millisecond response time while avoiding laser damage. We demonstrate its application by implementing a dual-plane two-photon laser scanning fluorescence microscope for in vivo recording of calcium transient of neurons in mouse neocortex.
Low-aberration liquid crystal lens with positive and negative focal length
Authors: Gao Jia-Jyun , Pan Jui-Wen , Jeng Shie-Chang
Published: August 2020

A low-aberration hole-patterned-electrodes (HPE) liquid crystal (LC) lens with positive and negative focal lengths is demonstrated in this Letter by using four hybrid-aligned nematic LC layers filled with dual-frequency LC materials. The diopter can be controlled from the positive lens (

0

D

∼

1.1

D

) to the negative lens (

0

D

∼

−

1.25

D

). The aberration is analyzed using the Zernike polynomial, and the wavefront optical path difference is improved from

2

λ

for the conventional one-layer HPE LC lens to less than

0.25

λ

for our proposed LC lens. The proposed LC lens does not require the use of a polarizer, increasing the optical efficiency two times compared with the conventional LC lens.
Polymer optical fibers for mechanical wave monitoring
Authors: Leal-Junior Arnaldo , Avellar Letícia , Frizera Anselmo , Antunes Paulo , Marques Carlos , Leitão Cátia
Published: August 2020

This Letter presents the development of a low-cost polymer optical fiber (POF) sensor for mechanical wave monitoring. The POF is fabricated using the light polymerization spinning process (LPS-POF) with Bisphenol-A as its main component, resulting in a highly flexible fiber. The proposed LPS-POF sensor is applied on the assessment of squared waves with different amplitudes, where the amplitude and dynamic responses are compared to the ones of a piezoelectric transducer (PZT). In static conditions, a determination coefficient (

R

2

) of 0.990 is obtained between the reference (PZT) and proposed sensors for the amplitude assessment of the wave. In dynamic analysis, the LPS-POF viscoelasticity is compensated using viscoelastic constitutive models, resulting in a

R

2

of 0.988 between the sensor responses, which indicate a mean error reduction of 21% when compared to the uncompensated responses in the amplitudes of different square waves. The dynamic analysis also shows the sensor capability of operating in frequencies as high as 25 Hz. Then, the sensor’s responses, compared to the input squared wave, show the possibility of wave velocity measurement. Therefore, with a LPS-POF sensor array, it is possible to monitor these parameters in practical applications.
Influence of pulse duration and repetition rate on mid-infrared cascaded supercontinuum
Authors: Kwarkye Kyei , Jensen Mikkel , Dasa Manoj K. , Woyessa Getinet , Jain Deepak , Bowen Patrick , Moselund Peter M. , Sidharthan Raghuraman , Chen Shaoxiang , Yoo Seongwoo , Petersen Christian R. , Bang Ole
Published: August 2020

We experimentally investigate the influence of varying pulse parameters on the spectral broadening, power spectral density, and relative intensity noise of mid-infrared (mid-IR) in-amplifier cascaded supercontinuum generation (SCG) by varying the pulse duration (35 ps, 1 ns, 3 ns) and repetition rate (100, 500, 1000 kHz). The system is characterized at the output of the erbium-ytterbium-doped in-amplifier SCG stage, the thulium/germanium power redistribution stage, and the passive ZBLAN fiber stage. In doing so, we demonstrate that the output of the later stages depends critically on the in-amplifier stage, and relate this to the onset of modulation instability.
Integrated Gires–Tournois interferometers based on evanescently coupled ridge resonators
Authors: Bezus Evgeni A. , Bykov Dmitry A. , Doskolovich Leonid L.
Published: August 2020

We propose integrated Gires–Tournois interferometers (GTIs) for guided modes of dielectric slab waveguides. The proposed GTIs consist of one or several dielectric ridge resonators separated by subwavelength-width grooves patterned into an abruptly terminated slab waveguide and operate at oblique incidence of the fundamental transverse-electric-polarized mode. The grooves act as partially reflective mirrors, whereas the end facet of the last ridge works in the total internal reflection regime and reflects all the incident radiation. We show that the single-ridge structure provides a nonlinear staircase-like phase response characteristic for GTIs. By using several properly arranged ridges, one can engineer group delay or group delay dispersion in a required spectral range. As an example, we design a three-ridge GTI providing an almost constant group delay dispersion in a 50-nm-wide wavelength range. The proposed planar GTIs may find application in integrated optical circuits for introducing or compensating for chromatic dispersion.
Quantitative phase imaging based on wavefront correction of a digital micromirror device
Authors: Hu Jing , Xie Xiwei , Shen Yibing
Published: August 2020

The strong need in materials and biological science has prompted the development of high-speed quantitative phase imaging. However, for phase retrieval applying digital micromirror devices (DMDs), the accuracy of the retrieved phase will be disturbed by the DMD-induced aberrations. Here, we propose a phase retrieval method based on measuring and correcting errors caused by phase non-uniformity of the device. Using only four binary amplitude masks and corresponding diffraction intensities, the proposed method achieves rapid convergence and high-quality reconstruction. The experiments prove the practical feasibility for general samples and the effective improvement of the retrieved phase accuracy.
Multifocal 1064  nm Raman imaging of carbon nanotubes
Authors: Ji Haojie , Nava Valeria , Yang Yu , Chan James W.
Published: August 2020

We show that multifocal 1064 nm Raman microscopy based on Hadamard-coded multifocal arrays is useful for imaging carbon nanotubes (CNTs) that would otherwise be damaged if a conventional single focus microscope design is used. The damage threshold for CNTs, dependent on laser power density and exposure time, limits the spectral detection sensitivity of single focus Raman imaging. With multifocal detection, the signal-to-noise ratio of the Raman spectra were improved by more than a factor of three, allowing for the G and D Raman bands of CNTs to be detected while avoiding specimen damage. These results lay the foundation for developing multifocal 1064 nm Raman microscopy as a tool for in situ imaging of CNTs in plant material.
Novel UV-transparent 2-component polyurethane resin for chip-on-board LED micro lenses
Authors: Bauer Joachim , Gutke Marko , Heinrich Friedhelm , Edling Matthias , Stoycheva Vesela , Kaltenbach Alexander , Burkhardt Martin , Gruenefeld Martin , Gamp Matthias , Gerhard Christoph , Steglich Patrick , Steffen Sebastian , Herzog Michael , Dreyer Christian , Schrader Sigurd
Published: August 2020

In this work we present a novel optical polymer system based on polyurethane elastomer components, which combines excellent UV transparency with high thermal stability, good hardness, high surface tension and long pot life. The material looks very promising for encapsulation and microlensing applications for chip-on-board (CoB) light-emitting diodes (LED). The extinction coefficient k, refractive index n, and bandgap parameters were derived from transmission and reflection measurements in a wavelength range of 200-890 nm. Thermogravimetry and differential scanning calorimetry were used to provide glass transition and degradation temperatures. The surface tension was determined by means of contact angle measurements. As proof of concept, a commercial InGaN-CoB-LED is used to demonstrate the suitability of the new material for the production of microlenses.
Effects of bone types, particle sizes, and gamma irradiation doses in feline demineralized freeze-dried bone allograft
Authors: Amelia Frizky , Abbas Basril , Darwis Darmawan , Estuningsih Sri , Noviana Deni
Published: August 2020

Background and Aim: Fracture cases significantly increase recently, demanding high quality of bone graft materials. This research aimed to evaluate the effects of bone types, particle sizes, and gamma irradiation doses on morphological performance and cell viability of feline demineralized freeze-dried bone allograft (DFDBA) through an in vitro study.

Materials and Methods: Feline DFDBA derived from feline cortical and cancellous long bones was processed into four different sizes: Group A (larger than 1000 μm), B (841-1000 μm), C (420-840 μm), and D (250-419 μm) for each type of bones. The materials were then irradiated with two doses of gamma rays, 15 and 25 kGy, resulting in 16 variants of feline DFDBA. The surfaces of each material were then observed with the scanning electron microscope (SEM). The in vitro evaluation of feline DFDBA was then performed using 3-(4,5-dimethythiazol-2)-2,5-diphenyltetrazolium bromide (MTT) assay with calf pulmonary artery endothelial cells.

Results: The MTT assay results showed that the lowest inhibition rate (14.67±9.17 %) achieved by feline DFDBA in Group A derived from cortical bones irradiated with 15 kGy. Group D generally showed high inhibition rate in both cancellous and cortical bones, irradiated with either 15 or 25 kGy. The SEM results showed that cancellous and cortical bones have numerous macropores and micropores structure in 170× and 3000×, respectively.

Conclusion: The material derived from cortical bones in Group A (larger than 1000 μm in particle size) irradiated with 15 kGy is the best candidate for further development due to its abundance of micropores structure and ability in preserving the living cells.
MEASUREMENT OF PHYSIOGRAPHIC CHANGES ON MANGROVE-FRINGED ESTUARIES AND COASTLINES
Authors: Bird E. C.F. , Barson M. M.
Published: August 2020

Studies of physiographic changes are in progress on mangrove-fringed shorelines in Westernport Bay in Victoria, and Cairns Bay in Queensland, Australia. Historical evidence of advance or retreat of these shorelines has been obtained from comparison of historical maps and air photographs with the present configuration, and supplemented by monitoring shoreline" changes with reference to established datum points during the past decade. In addition, changes in substrate level within the mangrove fringe, on mudflats to seaward, and on salt marshes (where present) to landward have been measured with reference to vertical changes on inserted poles, accretion over emplaced brick-dust layers, and changes in probe depths to underlying horizons (rock, sand, or peat) Results indicate that the advance of Avicennia marina on to mudflats is followed by relatively rapid and generally sustained vertical accretion related to interception of sediment within pneumatophore fields. Other mangroves or salt marsh species then replace Avicennia, and continued accretion leads to the development of a depositional marshland terrace, representing a re-shaping of the inter-tidal profile by the agency of vegetation. Mangroves that produce pneumatophore fields are considered to be more effective in trapping sediments than stilt rooted mangroves such as Rhizophora spp. or buttressed mangroves such as Bruguiera spp.
RELATIONSHIP BETWEEN TIDAL FORESTS (MANGROVES) AND COMMERCIAL SHRIMP PRODUCTION IN INDONESIA
Authors: Naamin Nurzali
Published: August 2020

An attempt has been made to relate the surface areas of tidal forest (mangrove) and the commercial shrimp production in those areas and adjacent waters in Indonesia. A significant linear relationship (a = 0.01) was obtained between these two variables as expressed in an equation : Y = 5.473 + 0.1128 X, where Y k the shrimp production in 103 tons and X is the mangrove surface area in 104 Ha. This relationship indicates that the shrimp production increases with the size of the tidal forest area implying that any reduction of the tidal forests, e.g. for industrial and agricultural purposes will cause a decrease in shrimp yield.
NUTRIENT CONCENTRATION AND PH IN THE CISADANE ESTUARINE AND COASTAL WATERS
Authors: Muchtar Muswerry
Published: August 2020

The study on the fluctuation of dissolved nutrient concentrations and acidity (pH) in the Cisadane Estuary was carried out in May 2004 October 2004 and July 2005. Inorganic phosphate, nitrate and silicate of the surface water were analyzed, using Spectrophotometer and pH was measured with a pH meter. Generally the nutrient concentrations in the estuary were higher compared to those in the coastal and offshore areas. The concentrations were gradually becoming lower and lower toward the open sea. Their fluctuation depended not only on the environmental condition but also on the water volurrie from the land and the mangrove forest in that area.
DISTRIBUTION OF MONOGONONT ROTIFERS, Branchionus spp IN NORTH SULAWESI
Authors: Rimper Joice , Kaswadji Richardus , Widigdo Bambang , Sugiri Nawangsari , Rumengan Inneke
Published: August 2020

In order to characterize the distribution pattern of rotifers Brachionus spp. in North Sulawesi, sample collections have been conducted at four locations, two at east coast and other two at west coast of North Sulawesi peninsula, which are connected to Maluku and Sulawesi Seas, respectively. At each location, a 40 p.m mesh size plankton net with a 0.3 m opening diameter was horizontally towed at three sites to represent coastal water, estuary and brachkiswater pond. Sampling periods were in January and August 2005 to represent west monsoon and east monsoon, respectively. Each sampling was performed twice a day during high and low tide. Some environmental factors were also measured in situ during the sampling. Three species of Brachionus were found during the survey, Brachionus rotundiformis, B. caudatus and B. quadridentatus. Their abundances were significantly different, both between locations and sampling sites. However, among the similar habitat such as between Manembo-nembo and Minanga brachkishwater ponds, B. rotundiforms abundance was not significantly different. This species was the most abundant compared to the other two species, in average 1984,4 ind/m3, while the other species was as low as 26,1 ind/m3 and 212,9 ind/m3 for B. caudatus and B. quadridentatus, respectively. The abundance of rotifers in northern areas connected to Molluccas Sea is higher compared to those in the southern areas connected to Sulawesi Sea. Distribution of B. caudatus is very similar to those of B. rotundiformis, while B. quadridentatus appears to have its specific pattern. Results of this study suggest that the abundance and species composition of the rotifers reflect trophic status of the aquatic ecosystem in the area. It is still awaiting future studies to elaborate the impacts of the trophic gradients in horizontal distribution of rotifers. Therefore, it is necessary to conduct a long term monitoring with emphasis on the structure of rotifer assemblages in a variety of sites subjected to environmental perturbations, including anthropogenic contaminant inputs.
PRELIMINARY EVIDENCE OF GROWTH INFLUENCE ON CARBON STABLE ISOTOPE COMPOSITION OF Undaria Pinnatifida
Authors: De Carvalho Matheus Carvalho , Hayashizaki Ken-Ichi , Ogawa Hisao , Kado Ryusuke
Published: August 2020

Cultured sporophytic thalli of Undaria pinnatifida were collected at different periods of the year from Okkirai Bay, northeastern Japan. 13C of the thalli collected in January was much higher than that of the thalli collected in March, and young thalli collected in March showed a tendency towards lower 13C values comparing with adult ones. U. pinnatifida thalli grew fast in January, while young thalli in March showed slow growth due to the light limitation caused by shading adult thalli. Therefore, the growth rate of thallus may relate to 13C. Ongoing studies aim to quantitatively describe this relation and to search similar results for other species.
GROWTH RESPONSES OF FIVE NON TOXIC ALEXANDRIUM SPECIES (DINOPHYCEAE) TO TEMPERATURE AND SALINITY
Authors: Lim Po-Teen , Leaw Chui-Pin , Kaga Shinnosuke , Sekiguchi Katsushi , Ogata Takehiko
Published: August 2020

Growth response of five clonal cultures of Alexandrium obtained from tropical and temperate waters were examined. Experiments were carried out in eighteen variable temperature-salinity conditions (temperatures of 15 °C, 20°C, and 25°C; salinities between 5 to 30 psu) under constant illumination of 150 ± 10.0 Amol m-2 s-' at 15:9 light:dark photo-cycle. Our results showed optimum growth of all Alexandrium species at 20 - 25°C. The salinity range for optimum growth however varied among the species. Growth rates of A. eine, A. insuetum, and A. fraterculus (0.28 — 0.37 day') were higher than those of A. leei and A. pseudogoniaulax under the same culture conditions (0.14 —0.22 day-'). The three temperate species showed positive growth at suboptimum temperature, 15°C, but the tropical species did not grow and died off. Salinity tolerance of the five species in decreasing order was A. pseudogoniaulax > A. leei > A. insuetum > A. affine > A. fraterculus. Results of the present study showed vast variations in salinity tolerance among the Alexandrium species regardless the geographical origins. Adaptation of the temperate species at higher temperature indicated that the species might proliferate in warm tropical waters.
POTENTIAL TOXIC CYANOBACTERIA IN THREE LAKES OF JAKARTA-BOGOR AREA, INDONESIA
Authors: Prihantini Nining Betawati , Widyawan Arya , Rianto Ronny , Ariyani Yuni , Wardhana Wishnu , Hendrayanti Dian
Published: August 2020

The research was aimed to understand the composition and dominancy of aquatic microalgae, and to know the potential toxicity of Cyanobacteria occuring in three lakes of Jakarta-Bogor area. The study was done in 2006. The sampling sites were Lake Sunter 2 (North Jakarta), Lake Babakan (South Jakarta), and Lake Lido (Bogor). The water samples were taken using plankton-net (20 tan mesh) with horizontal tow. The results showed that. the number of microalgal genera in Sunter 2, Babakan, and Lido were different, i.e. 10 genera, 40 genera, and 14 genera, respectively. Cyanobacteria were dominant in Sunter 2 (96%) and Babakan (90.01%). The dominant Cyanobacteria in Sunter 2 was Planktothrix agardhii (53.48%), whereas in Babakan was Chroococcus dispersus (68.52%). The second abundant Cyanobacteria in Sunter 2 was Arthrospira (42.54%). Planktothrix agardhii and Arthrospira are known to produce harmful toxin.