Mode hopping strongly affects observability of dynamical instability in optical parametric oscillators

Theoretical investigations of dynamical behavior in optical parametric oscillators (OPO) have generally assumed that the cavity detunings of the interacting fields are controllable parameters. However, OPOs are known to experience mode hops, where the system jumps to the mode of lowest cavity detuning. We note that this phenomenon significantly limits the range of accessible detunings and thus may prevent instabilities predicted to occur above a minimum detuning from being evidenced experimentally. As a simple example among a number of instability mechanisms possibly affected by this limitation, we discuss the Hopf bifurcation leading to periodic behavior in the monomode mean-field model of a triply resonant OPO and show that it probably can be observed only in very specific setups.Comment: submitted to Phys. Rev.

Spatial repartition of local plastic processes in different creep regimes in a granular material

Granular packings under constant shear stress display below the Coulomb limit, a logarithmic creep dynamics. However the addition of small stress modulations induces a linear creep regime characterized by an effective viscous response. Using Diffusing Wave Spectroscopy, we investigate the relation between creep and local plastic events spatial distribution ("hot-spots") contributing to the plastic yield. The study is done in the two regimes, i.e. with and without mechanical activation. The hot-spot dynamics is related to the material effective fluidity. We show that far from the threshold, a local visco-elastic rheology coupled to an ageing of the fluidity parameter, is able to render the essential spatio-temporal features of the observed creep dynamics

The Tao Te Ching [Laozi] /Lao-tzu Metaphysics (What is existence?)

As Chinese philosophies enter the global marketplace, Taoist ideas are emerging with greater frequency. In order to make Zhou Dynastic Taoist ideas accessible to Western acculturated readers a more conventionally “Western” examination of a key Taoist text the Tao te ching/Dao de jing by Lao Tzu/Laozi is presented in this paper. I examine the foundational metaphysics presented in the Tao te ching. Lao Tzu contends that the Tao transcends all conditions, all conceptualization and naming, presenting an inherent conundrum. I argue that by evoking a-rational and experiential discourse the Tao te ching attempts to impart impressions of The Tao. By this an example is set forth of the paramount value of wei-wu-wei (naturally derived action) as a greater means to achieving understanding than the more didactic approach favored by Lao Tzu’s contemporary Confucius (Kung-fu-tzu) and the thinkers that followed him. These two schools of thought share cosmology theories: e.g. The Tao, ch\u27i [qi]气, yin/yang阴/阳and te 德. However, their prescriptions for appreciating and harmonizing with these forces are mirror images of one another. In examining Taoist metaphysics through a more Western philosophical lens I attempt to give the reader a way to extract deeper mean from the Tao te ching

Organometallic Ruthenium Complexes of Novel Thiosemicarbazones

We present the preliminary results of a study of two novel thiosemicarbazones (TSCs) and theirruthenium complexes. The TSCs were prepared by refluxing thiosemicarbazide with 9-anthraldehyde or benzanthrone in ethanol for 3 hours. The metal complex of each ligand (complex I =[(r|6 -C6H6 )Ru(9-ant-TSC )(C1)]C1 and complex II= [(r|6 -C6H6 )Ru(benz-TSC)(Cl)]Cl) was prepared by refluxing the appropriate TSC with [(r|6 -C6H6 )RuCl 2 ] r The compounds were characterized using infrared, ultraviolet-visible, and NMRspectroscopy. Two different methods, the disk diffusion test and luminometry, were used to test the compounds against a variety of different bacterial strains for antibacterial activity. The most optimistic results were obtained for the 9-ant-TSC ligand, especially in relation to activity against Gram (+) bacteria. The metal complexes showed no measurable activity and further biological testing of the metal complexes is currently being conducted

MAAP Transition from ISO 9001:2015 to ISO 21001:2018 the new quality standard in education organization

Sustainable success has become an ever-more-important future goal in all industries but challenges arise from the advent of fourth industrial revolution and revisions of national and international regulations directly affect the shipping industry trickling down to the Maritime Education and Training Institutions (METI). Thus, a metamorphosis of standards for a maritime school like the Maritime Academy of Asia and the Pacific (MAAP) transitioning to a more tailor-fit Quality Standards is inevitable to manage the changes in educational organizations. ISO 21001:2018 has been published in oder to replace IWA 2:2007. This prompted the Academy to evolve from the traditional ISO 9001:2015 standard. This paper aims to discuss the STCW ’78 (as amended) requirements for Quality Standard System and how the new standard in educational and training organizations complies with it. The paper shall also serve as a resource and reference for those schools that are looking for standards that can attune their management systems gearing towards safer, cleaner, and excellent shipping by having a competent seafarer through a certified Educational Organization Management System. With the vision of the academy to be the leading institution of excellence in maritime and training the Asia-Pacific region and beyond, certification with the standard is indeed a milestone and breakthrough

Design of a Small Scale Roll to Roll Device

In the soft robotics field, hyperelastic polymer films are used in conjunction with eutectic gallium indium to create flexible strain gages. However, rapid large scale manufacturing methods of such sensors have yet to be developed. Developing new manufacturing methods will allow for researchers to build and test new soft sensor concepts faster but also pave the way for future mass-production of these sensors for consumer or industrial consumption. One of those methods would be a Roll to Roll System (R2R) similar to those used to in the publication industry. In this context, Polyethylene terephthalate (PET) film rolls will be used as a medium upon which hyperelastic polymer films and eutectic gallium indium will be deposited on. This research paper will discuss the design of a small scale roll to roll system used in the Purdue Fabrication Laboratory. After designing and building a scaled down R2R prototype system, we found that this system must be able to adequately control the PET web tension, and web position to ensure the accuracy of the printed of the soft sensor. Due to an absence of a readily available and economical R2R device made specifically for soft robotics, our laboratory built one that would be able to interface with laboratory equipment and that enabled an efficient manufacturing of flexible sensors. This device will serve as a step towards the development of large scale soft robotics printing

Dark Energy Survey Year 3 results: Cosmology from cosmic shear and robustness to data calibration

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMThis work, together with its companion paper, Secco, Samuroff et al. [Phys. Rev. D 105, 023515 (2022)PRVDAQ2470-001010.1103/PhysRevD.105.023515], present the Dark Energy Survey Year 3 cosmic-shear measurements and cosmological constraints based on an analysis of over 100 million source galaxies. With the data spanning 4143 deg2 on the sky, divided into four redshift bins, we produce a measurement with a signal-to-noise of 40. We conduct a blind analysis in the context of the Lambda-Cold Dark Matter (ΛCDM) model and find a 3% constraint of the clustering amplitude, S8 ≡ σ8 (ωm/0.3) 0.5 = 0.759-0.023+0.025. A ΛCDM-Optimized analysis, which safely includes smaller scale information, yields a 2% precision measurement of S8 = 0.772-0.017+0.018 that is consistent with the fiducial case. The two low-redshift measurements are statistically consistent with the Planck Cosmic Microwave Background result, however, both recovered S8 values are lower than the high-redshift prediction by 2.3σ and 2.1σ (p-values of 0.02 and 0.05), respectively. The measurements are shown to be internally consistent across redshift bins, angular scales and correlation functions. The analysis is demonstrated to be robust to calibration systematics, with the S8 posterior consistent when varying the choice of redshift calibration sample, the modeling of redshift uncertainty and methodology. Similarly, we find that the corrections included to account for the blending of galaxies shifts our best-fit S8 by 0.5σ without incurring a substantial increase in uncertainty. We examine the limiting factors for the precision of the cosmological constraints and find observational systematics to be subdominant to the modeling of astrophysics. Specifically, we identify the uncertainties in modeling baryonic effects and intrinsic alignments as the limiting systematic

Aftershocks as a time independant phenomenon

Sequences of aftershocks following Omori's empirical law are observed after most major earthquakes, as well as in laboratory-scale fault-mimicking experiments. Nevertheless, the origin of this memory effect is still unclear. In this letter, we present an analytical framework for treating labquake and earthquake catalogs on an equal footing. Using this analysis method, we show that when memory is considered to be in deformation and not in time, all data collapse onto a single master curve, showing that the timescale is entirely fixed by the inverse of the strain rate