Thermo-Electro-Mechanical Characterization of PDMS-Based Dielectric Elastomer Actuators

The present contribution aims towards a thermo-electro-mechanical characterization of dielectric elastomer actuators (DEA) based on polydimethylsiloxane (PDMS). To this end, an experimental setup is proposed in order to evaluate the PDMS-based DEA behavior under the influence of various rates of mechanical loading, different ambient temperatures, and varying values of an applied electric voltage. To obtain mechanical, electro-mechanical and thermo-mechanical experimental data, the passive behavior of the material, as well as the material’s response when electrically activated, was tested. The influence of the solid electrode on the dielectric layer’s surface was also examined. Moreover, this work focuses on the production of such DEA, the experimental setup and the interpretation and evaluation of the obtained mechanical hysteresis loops. Finite element modeling approaches were used in order to model the passive and the electro-mechanically active response of the material. A comparison between experimental and simulation results was performed.

Development and Evaluation of a Chinook Salmon Smolt Swimming Behavior Model

Hydrologic currents and swimming behavior influence routing and survival of emigrating Chinook salmon in branched migratory corridors. Behavioral particle-tracking models (PTM) of Chinook salmon can estimate migration paths of salmon using the combination of hydrodynamic velocity and swimming behavior. To test our hypotheses of the importance of management, models can simulate historical conditions and alternative management scenarios such as flow manipulation and modification of channel geometry. Swimming behaviors in these models are often specified to match aggregated observed properties such as transit time estimated from acoustic telemetry data. In our study, we estimate swimming behaviors at 5 s intervals directly from acoustic telemetry data and concurrent high-resolution three-dimensional hydrodynamic model results at the junction of the San Joaquin River and Old River in the Sacramento-San Joaquin Delta, California. We use the swimming speed dataset to specify a stochastic swimming behavior consistent with observations of instantaneous swimming. We then evaluate the effect of individual components of the swimming formulation on predicted route selection and the consistency with observed route selection. The PTM predicted route selection fractions are similar among passive and active swimming behaviors for most tags, but the observed route selection for some tags would be unlikely under passive behavior leading to the conclusion that active swimming behavior influenced the route selection of several tagged smolts.

On the electrical passivity of astrocyte potassium conductance

Predominant expression of leak-type K+ channels provides astrocytes a high membrane permeability to K+ ions and a hyperpolarized membrane potential that are crucial for astrocyte function in brain homeostasis. In functionally mature astrocytes, the expression of leak K+ channels creates a unique membrane K+ conductance that lacks voltage-dependent rectification. Accordingly, the conductance is named ohmic or passive K+ conductance. Several inwardly rectifiers and two-pore domain K+ channels have been investigated for their contributions to passive conductance. Meanwhile, gap junctional coupling has been postulated to underlie the passive behavior of membrane conductance. It is now clear that the intrinsic properties of K+ channels and gap junctional coupling can each act alone or together to bring about a passive behavior of astrocyte conductance. Additionally, while the passive conductance can generally be viewed as a K+ conductance, the actual representation of this conductance is a combined expression of multiple known and unknown K+ channels, which has been further modified by the intricate morphology of individual astrocytes and syncytial gap junctional coupling. The expression of the inwardly rectifying K+ channels explains the inward-going component of passive conductance disobeying Goldman-Hodgkin-Kate (GHK) constant field outward rectification. However, the K+ channels encoding the outward-going passive currents remain to be determined in the future. Here, we review our current understanding of ion channels and biophysical mechanisms engaged in the passive astrocyte K+ conductance, propose new studies to resolve this long-standing puzzle in astrocyte physiology, and discuss the functional implication(s) of passive behavior of K+ conductance on astrocyte physiology.

THE INFLUENCE OF THE LEVEL OF EDUCATION ON THE BEHAVIORAL PATTERNS ASSOCIATED WITH THE ACCESS TO MEDICAL CARE OF THE POPULATION OF OLDER AGE GROUPS

The purpose of the study: to study the influence of the level of education on the behavioral patterns associated with medical care of the population of older age groups. Materials and methods of research. The results of an anonymous survey of 1,045 people of both sexes aged 60 years and older were analyzed. The questionnaire included a question about the reasons for visiting medical organizations. The results were evaluated separately for men and women in two age groups of 60–74 years and 75 years and older. Results. There were no significant gender differences in the characteristics of medical activity among the studied cohorts of older age groups. The most common form of behavior regardless of gender was the reactive type, when seeking medical help occurred as a result of health problems. A high level of education contributes to a change in behavior towards a greater prevalence of active behavior in relation to the reasons for seeking medical help. These patterns are observed regardless of gender and are more pronounced in the age group of 75 years and older. Men and women with a low level of education are more likely to choose a reactive type of behavior when seeking medical help occurs after the appearance of health problems. The frequency of passive behavior does not depend on the level of education and is more often recorded in the age group of 60–74 years.

4D printing of wooden actuators: encoding FDM wooden filaments for architectural responsive skins

PurposeConventional motion mechanisms in adaptive skins require rigid kinematic mechanical systems that require sensors and actuation devices, hence impeding the adoption of zero-energy buildings. This paper aims to exploit wooden responsive actuators as a passive approach for adaptive facades with dynamic shading configurations. Wooden passive actuators are introduced as a passive responsive mechanism with zero-energy consumption.Design/methodology/approachThe study encodes the embedded hygroscopic parameters of wood through 4D printing of wooden composites as a responsive wooden actuator. Several physical experiments focus on controlling the printed hygroscopic parameters based on the effect of 3D printing grain patterns and infill height on the wooden angle of curvature when exposed to variation in humidity. The printed hygroscopic parameters are applied on two types of wooden actuators with difference in the saturation percentage of wood in the wooden filaments specifically 20% and 40% for more control on the angle of curvature and response behavior.FindingsThe study presents the ability to print wooden grain patterns that result in single and double curved surfaces. Also, printing actuators with variation in infill height control each part of wooden actuator to response separately in a controlled passive behavior. The results show a passive programmed self-actuated mechanism that can enhance responsive façade design with zero-energy consumption through utilizing both material science and additive manufacturing mechanisms.Originality/valueThe study presents a set of controlled printed hygroscopic parameters that stretch the limits in controlling the response of printed wood to humidity instead of the typical natural properties of wood.

Perilaku Pencarian Informasi Mengenai Kebijakan Sekolah Tatap Muka oleh Orang Tua Siswa di kota Malang

Recently, the Ministry of Education and Culture has established a policy for implementing face-to-face schools. Regarding this policy, students’ parents become a key point in order to make decisions to allow children to attend face-to-face schooling. Before decision making, parents must first reduce uncertainties and lack of information related to the policy. This study discusses the information-seeking behavior of parents related to face-to-face school policies and the decision-making. The method used is descriptive survey. Data collected through online surveys and interviews. The results showed that parents did the active and passive behavior on information seeking. The school (teachers, homeroom teachers, principals, etc.) is the most frequently referred source of information by parents and is considered the most trusted source of information. The most important information needed by parents is regarding the readiness of the school in the implementation of face-to-face learning during the pandemic. In decision-making process, parents often use information sources through online media and discussions with other parents. The majority of parents will delay decision making if the information obtained is deemed insufficient, while on the other hand parents can also experience decision-making failure due to information overload. Belakangan ini Kemdikbud telah menetapkan kebijakan pelaksanaan sekolah tatap muka. Selain akademisi, orang tua menjadi pihak krusial dalam hal ini terutama berkaitan dengan pengambilan keputusan untuk mengizinkan anak mengikuti pelaksanaan sekolah tatap muka. Sebelum mengambil keputusan terlebih dahulu orang tua harus mereduksi berbagai ketidakpastian dan kurangnya informasi terkait kebijakan tersebut. Penelitian ini membahas mengenai perilaku pencarian informasi yang dilakukan orang tua terkait kebijakan sekolah tatap muka hingga proses pengambilan keputusan. Metode yang digunakan adalah survei deskriptif dengan teknik pengumpulan data melalui survei dan wawancara. Hasil penelitian menunjukkan bahwa orang tua melakukan pencarian informasi secara aktif dan pasif. Pihak sekolah (guru, wali kelas, kepala sekolah, dsb) menjadi sumber informasi yang paling sering dirujuk oleh orang tua siswa sekaligus dianggap sebagai sumber informasi yang paling terpercaya. Informasi yang dianggap paling penting oleh orang tua siswa adalah mengenai kesiapan sekolah dalam pelaksanaan pembelajaran tatap muka di masa pandemi. Adapun dalam pengambilan keputusan orang tua seringkali memanfaatkan sumber informasi melalui media daring dan diskusi bersama orang tua siswa lainnya. Mayoritas orang tua akan menunda pengambilan keputusan jika informasi yang didapatkan dirasa belum cukup, sementara di sisi lain orang tua juga dapat mengalami kegagalan pengambilan keputusan karena paparan informasi yang terlalu berlebihan.

Concept, types and signs of responsibility in the field of medical activities

The development of medical science, the improvement of the living standards of the population and the establishment of democratic institutions contribute to the increase of the requirements for the activity of medical workers and to the increase of cases of bringing them to justice for improper performance of professional duties. Civil law distinguishes between types of liability according to different criteria. Thus, on the basis of the rights and obligations, for the violation of which liability is established, it is divided into contractual and non-contractual. Contractual and non-contractual civil liability have some common generic features. Liability in medical activities arises in case of violation of rights and responsibilities. The activities of health professionals (doctors, nurses, support staff) in any case, aimed at the patient, he receives medical care, taking into account his health, physical condition, and aim at positive changes in the patient's health. In the case of contractual liability, the terms of the contract are violated, in the case of non-contractual (tort) liability between the violator and the victim before the violation there were absolute legal relations. The behavior of the offender must be active, ie passive behavior is not the basis for tortious liability, but only if there are special rules of law that provide only for active behavior (doctors). Tort liability damages the general prohibition, where potentially harmful conduct is not clearly defined by law, as any active conduct is illegal and associated with the occurrence of the damage. Contractual liability will arise in compliance with the terms of liability, especially the causal link, ie the objectively existing link between the wrongful conduct of the debtor and the adverse consequences that have occurred. The classic features of the contract, of course, are more clearly manifested in private medical services (eg, dentists, private medical institutions), there are contractual relationships. Liability in the field of medical activity is a type of legal liability, ie the implementation of a sanction of a legal norm, which by its nature is a means of coercion, is accompanied by condemnation by the state and is expressed in imposing on the perpetrator of violation of intangible consequences of a material nature.

Corrosion characterization of the experimental alloy Ti-35Nb-7Zr-5Ta by electrochemical techniques

The objective of the present study was to evaluate the corrosion resistance of the experimental alloy Ti-35Nb-7Zr-5Ta, modified by laser beam, in a physiological solution of 0.9% NaCl. This evaluation was carried out by open circuit potential analysis (EOCP), potentiodynamic polarization curves and cyclic polarization curves. The open circuit potential curves show the specimen irradiated by laser beam at 35 Hz presented a more stable and corrosion resistant surface. It was observed in the polarization curves, low current densities in the order of nA /cm2, for all specimen indicating an expected passive behavior for the investigated alloy. The cyclic polarization curves show that for specimen treated with laser, the potential for repassivation (Er) is greater in relation to the potential for corrosion (Ecorr), which indicates greater resistance to corrosion of metal alloys when treated with laser.