A seesaw-type MEMS switch with enhanced contact force: the first results

Outstanding working characteristics make microelectromechanical systems (MEMS) switches attractive for many applications. However, the lack of reliability prevents their commercial success. Due to the small size, MEMS switches develop low contact force compared to their macroscopic counterparts, which leads to instability and fast increase of the contact resistance. This work describes the switch providing significantly larger force than the previously reported device. The enlargement is achieved by the modified shape of the beam and electrodes with the same footprint and lower actuation voltage. Design, simulation, fabrication and first experimental results for the switch are presented.

Carreras por montaña en la Comunitat Valenciana (1995-2019). Evolución, distribución territorial e incidencia en áreas naturales protegidas / / / \ \ \ Mountain races in the Valencian Community (1995-2019). Evolution, territorial distribution and incidence in protected areas

Resumen: El rápido crecimiento de las carreras por montaña, ha motivado durante los últimos años su estudio. Aun son pocas las referencias bibliográficas que podemos encontrar a escala local, aunque algunas a nivel de España. Existen diferencias regionales, que demandan la necesidad de examinar este tipo de pruebas a una escala detallada. La Comunitat Valenciana, dada su extensión forestal y porcentaje de territorio montañoso (56 %), el número de espacios naturales (646) y superficie total protegida (40 %), se convierte en un buen ámbito de estudio. Una revisión bibliográfica y un análisis de la información recogida ha permitido determinar el número y la evolución de esta práctica en los últimos 25 años, la distribución espacial y temporal, y otras características de interés, como la tipología y los actores que intervienen. La tendencia a realizar este tipo de actividades dentro de Espacios Naturales Protegidos, incita a conocer el alcance que reciben diferentes áreas protegidas, elegidas para el estudio, que vistos los resultados es bastante significativo. Surge entonces la necesidad de plantearse, si los métodos de gestión y regulación son adecuados. El objetivo no es prohibir las carreras por montaña, puesto que desde una perspectiva social y económica aportan muchos beneficios, sino hacer compatible su desarrollo con los valores de conservación y protección de los espacios naturales. Palabras clave: Carreras por montaña, Comunidad Valenciana, Espacios Naturales Protegidos, Impacto ambiental. Abstract: The fast increase of the mountain races events, has motivated recently the appearance of several studies. Still are few the available references at local scale, although some at Spanish level. There are regional differences that enhance the need of study that king of events in a local scale. The Comnunitat Valenciana, with large forested mountain areas (56 %), the number of natural reserves (646) and total protected proportion (40 %), becomes a good case of study. A literature review and an analysis of the collected information allowed to know the figures an evolution of the that practice during the last 25 years, its spatial and temporal distribution, among other relevant characteristics, like the kind of events and involved actors. The tendency to organize that kind of events on Natural Protected Areas enhance the needs of evaluation of the affection to that areas, chosen for this paper, that seem clearly significative. The need arises then to consider whether the management and regulation methods are adequate. The objective is not to limit the mountain races, since from a social and economic perspective they provide many benefits, but to make their existence compatible with the protection and conservation of the natural areas. Key words: Trail running, Valencia Autonomous Region, Natural protected areas, Environmental impact.

Analysis of Usage of SQL Detector Based on Artificial Intelligence in Serverless Architecture

Introduction. The widespread use of the Internet leads to a fast increase of the quantity of data that goes into it. This generates interest in intruders which try different approaches to steal this data. One of the most popular approaches is SQL injection. There are a lot of measures which help to prevent and decrease the risk of being subjected to this attack: usage of code analysis tools, usage of firewalls which can filter dangerous traffic etc. Usage of reverse proxy is analysed in this article, which with the help of machine learning algorithms checks requests for SQL injections and based on the result passes or forbids the request to go. It is worth mentioning that such a solution is not a replacement of human expertise but addition to it, which with the help of big data can give an accurate result in most cases. The purpose of the paper is to analyse and show effectiveness of usage of machine learning in information system security provisioning tasks with the system working in serverless architecture. Results. A system is designed and developed which with the help of machine learning classifies received requests. The system is deployed to the cloud hosting Google Cloud Platform and integrated into an application which is designed according to the serverless architecture principles. Multiple algorithms were used to compare effectiveness of the system and percentage of successful results were calculated for each of them. Also, an average time of request execution is calculated for each algorithm. Conclusions. Each algorithm’s result of successful request classification is above 90% which is considered to be more than acceptable. The result can be improved using more data to train machine learning models. The system fits for work in serverless applications thanks to the simplicity of its integration but it should be considered if it fits from a hardware rent point of view. Keywords: machine learning, Google Cloud Platform, security, SQL injection.

Measurement of Continuous Cooling Transformation Curve and High Temperature Mechanical Properties for 12Mn Steel

The dilatometer curves of continuous cooling transformation of 12Mn steel were measured with Formastor-FⅡthermal mechanical simulator．The steel's undercooled austenite phase continuous cooling transformation curves ( CCT curves) were established by means of the dilatometer method and the metallographic-hardness measurement method． The effect of cooling rate on microstructure and hardness of the steel was studied． CCT curve of test steel was simulated by JMatPro. The results show that the Ac1 and Ac3 of the experimental steel are 692 ℃ and 855 ℃ ; the microstructure obtained is made of ferrite，pearlite and bainite．The ferrite transformation and pearlite transformation occur at a slower cooling rate，in which the ferrite is dominant. When the cooling rate is greater than 4.25 ℃ / s bainite transformation happens．As the cooling rate increases，microstructure or grains become finer．The hardness of the tested steel with increasing cooling rate shows a trend of first fast increase and soon decrease．The simulation results are consistent with the measured CCT law. The high temperature mechanical properties of 12mn steel round billet were tested by gleeble-1500d thermal / mechanical simulator. The tensile strength, reduction of area and stress-strain curves of the billet were obtained in the range of 600-1300 ℃.

Indirect to direct band gap crossover in two-dimensional WS2(1−x)Se2x alloys

In atomically thin transition metal dichalcogenide semiconductors, there is a crossover from indirect to direct band gap as the thickness drops to one monolayer, which comes with a fast increase of the photoluminescence signal. Here, we show that for different alloy compositions of WS2(1−x)Se2x this trend may be significantly affected by the alloy content and we demonstrate that the sample with the highest Se ratio presents a strongly reduced effect. The highest micro-PL intensity is found for bilayer WS2(1−x)Se2x (x = 0.8) with a decrease of its maximum value by only a factor of 2 when passing from mono-layer to bi-layer. To better understand this factor and explore the layer-dependent band structure evolution of WS2(1−x)Se2x, we performed a nano-angle-resolved photoemission spectroscopy study coupled with first-principles calculations. We find that the high micro-PL value for bilayer WS2(1−x)Se2x (x = 0.8) is due to the overlay of direct and indirect optical transitions. This peculiar high PL intensity in WS2(1−x)Se2x opens the way for spectrally tunable light-emitting devices.

Glutamate Dehydrogenase Applicability in Clinical Practice

Glutamate dehydrogenase (GLDH) catalyzes reversible deamination of glutamate into alpha-ketoglutarate and ammonium ion. In the metabolism of a cell, GLDH has the key role of acting as an interface between carbohydrates and amino acids in the vicinity of the citric acid cycle and urea cycle. In the brain, GLDH appears in astrocytic processes associated with glutamatergic terminals, but it is also involved in glia metabolic processes. GLDH probably protects postsynaptic membranes against the neuroexcitotoxic glutamate effect. GLDH is an equally accurate marker of alcoholism in comparison to others, if its significantly faster decrease is taken into consideration. Watching changes in the activity of laboratory markers of alcoholism, after cessation of drinking, is an effective yet overlooked aid in diagnostics. The fast increase of leukocytes GLDH activity is specific for alcohol addiction. Alcohol consumption reduces GLDH activity to some extent and consecutively it could lead to increased protein production and strengthen of diminished leukocyte protective ability. The gradual decrease in GLDH activity may be one of key factors for neurodegenerative ageing processes. The decrease in GLDH activity in the cerebrospinal fluid of patients with neurodegenerative disorders may be one of the reasons for the neuroexcitotoxic glutamate effect. The probable decrease in GLDH activity in the cerebrospinal fluid of patients with neurodegenerative disorders and of patients with nerve, nerve root and plexus disorders needs further investigations to be adequately understood.

Modification of nanoporous structure and surface of carbon electrodes for use in power storage systems

Method for modification of nanoporous structure and surface of carbon materials to be used as supercapacitor electrodes has been developed and optimized as to the microwave treatment (MWT) regimes. Mechanisms of MWT due to the dielectric and Maxwell-Wagner polarization effects have been discussed. It has been found that due to the dielectric polarization and a fast increase in temperature inside pores, which were saturated with etching agents (water, oxalic or formic acid) beforehand, the selective pore etching “from inside” can occur that increases the pore size and, as a result, increases the electrostatic capacitance of supercapacitors by 20%. Processes of pore structure development have been optimized as to the treatment duration and the carbon material grain size. It has also been shown that the pore surface can be modified with Nitrogen heteroatoms due to the MWT of carbon and melamine powder mixtures. This modification enables to step up the supercapacitor rated voltage from commonly used 2.7V to 3.0V that additionally increases the supercapacitor energy density by 23%. Yet another advantage of MWT is a significant reduction in treatment duration (from hours to minutes) and in energy consumption; besides, the loss of carbon material does not exceed 10% due to the mostly “from inside” etching process.

Golden jackal, a natural disperser or an invasive alien species in Slovakia? A summary within European context

This summary provides an overview of the golden jackal (Canis aureus) categorization in Europe with particular focus on its presence in Slovakia. The distribution range of this species in Europe has been expanding in recent decades. Currently, European population is in constant and fast increase, widening their ranges towards Central and Eastern Europe and more recently in some western countries. All over Europe, the categorization of the golden jackal status is discussed with some controversial. A recent genetic study helped to determine that golden jackals do not meet the established three criteria, which categorize a species as an invasive alien species. In Slovakia, golden jackals’ numbers grown considerably in the last decade and with an increasing of their distribution through the country it became a permanent species of the Slovak fauna. The only internal status is the hunting Act no. 274/2009, which classifies it as, game species. The fast adaptation and dispersion through Slovakia can be considered similar to the behaviour of an invasive species, as suggested in previous studies in Hungary. Based on widely accepted definitions, agreed under international legal instruments, it is quite clear that the term ‘Invasive Alien Species’ only encompasses non-native species specifically introduced by humans (intentionally or accidentally). Following this Invasive Alien Species terminology, golden jackals cannot be categorized as such in Slovakia. The natural expansion, the growing ranges, and the increase in numbers of the golden jackal in Slovakia in the last decades points to a need to improve the knowledge of the species.