Dependence of chaotic behavior on optical properties and electrostatic effects in double beam torsional Casimir actuation

We investigate the influence of Casimir and electrostatic torques on double beam torsional microelectromechanical systems with materials covering a broad range of conductivities of more than three orders of magnitude. For the frictionless autonomous systems, bifurcation and phase space analysis shows that there is a significant difference between stable and unstable operating regimes for equal and unequal applied voltages on both sides of the double torsional system giving rise to heteroclinic and homoclinic orbits, respectively. For equal applied voltages, only the position of a symmetric unstable saddle equilibrium point is dependent on the material optical properties and electrostatic effects, while in any other case there are stable and unstable equilibrium points are dependent on both factors. For the periodically driven system, a Melnikov function approach is used to show the presence of chaotic motion rendering predictions of whether stiction or stable actuation will take place over long times impossible. Chaotic behavior introduces significant risk for stiction, and it is more prominent to occur for the more conductive systems that experience stronger Casimir forces and torques. Indeed, when unequal voltages are applied, the sensitive dependence of chaotic motion on electrostatics is more pronounced for the highest conductivity systems.Comment: 24 pages, 11 figure

Zero tension Kardar-Parisi-Zhang equation in (d+1)- Dimensions

The joint probability distribution function (PDF) of the height and its gradients is derived for a zero tension $d+1$-dimensional Kardar-Parisi-Zhang (KPZ) equation. It is proved that the height`s PDF of zero tension KPZ equation shows lack of positivity after a finite time $t_{c}$. The properties of zero tension KPZ equation and its differences with the case that it possess an infinitesimal surface tension is discussed. Also potential relation between the time scale $t_{c}$ and the singularity time scale $t_{c, \nu \to 0}$ of the KPZ equation with an infinitesimal surface tension is investigated.Comment: 18 pages, 8 figure

A new approach for land degradation and desertification assessment using geospatial techniques

© Author(s) 2018. Land degradation reduces the production of biomass and vegetation cover for all forms of land use. The lack of specific data related to degradation is a severe limitation for its monitoring. Assessment of the current state of land degradation or desertification is very difficult because this phenomenon includes several complex processes. For that reason, no common agreement has been achieved among the scientific community for its assessment. This study was carried out as an attempt to develop a new approach for land degradation assessment, based on its current state by modifying of Food and Agriculture Organization (FAO)-United Nations Environment Programme (UNEP) index and the normalized difference vegetation index (NDVI) index in Khuzestan province, southwestern Iran. Using the proposed evaluation method it is easy to understand the degree of destruction caused by the pursuit of low costs and in order to save time. Results showed that based on the percent of hazard classes in the current condition of land degradation, the most and least widespread areas of hazard classes are moderate (38.6 %) and no hazard (0.65 %) classes, respectively. Results in the desert component of the study area showed that the severe class is much more widespread than the other hazard classes, which could indicate an environmentally dangerous situation. Statistical results indicated that degradation is highest in deserts and rangeland areas compared to dry cultivated areas and forests. Statistical tests also showed that the average degradation amount in the arid region is higher than in other climates. It is hoped that this study's use of geospatial techniques will be found to be applicable in other regions of the world and can also contribute to better planning and management of land

Developing a method for identification of net zones using log data and diffusivity equation

International audienceDistinguishing productive zones of a drilled oil well plays a very important role for petroleum engineers to decide where to perforate to produce oil. Conventionally, net pay zones are determined by applying a set of cutoffs on perophysical logs. As a result, the conventional method finds productive intervals crisply. In this investigation, a net index value is proposed, then; diffusivity equation is utilized to calculate the proposed index value. The new net determination method is applied on the interval of Sarvak Formation of two datasets of two nearby wells. The best advantage of this newly developed net determination method is its fuzzy output. Fuzzy net pay determination is valuable in grading pay zones and not classifying all productive zones in a single class. Another advantage of the proposed net determination method is its higher accuracy in identifying productive zones in comparison with cutoff based method

Application of Efficient Express Sequence Tags Information for Classification and Functional Study of Simple Sequence Repeats in Cattle Testis Tissue

Genomic markers play an important role in tracing the flow of genetic causality of observable signals in animals and plants. In farm animals, the participation of male animals in the gene pool of subsequent generations are much higher than female animals and testes are the most important organs of the male reproductive system. This study was conducted to investigate simple sequence repeats (SSR) within the expressed sequence tags (ESTs) in order to classify the Bos taurus testis tissue’s genes for their relationship and specificity with related reproductive domains. A total of 48,549 publicly available EST sequences from cattle testis tissue downloaded from GenBank database, out of which, 10,237 sequences that their library made from testis tissue were extracted and specialized as the studied sequences using several searching tools and software. Across these selective sequences, 2,039 contigs, 5,097 singletons, and 153 SSRs were detected. EST-SSRs were subsequently evaluated using GenBank and categorized based on their functions in biological systems of dairy cattle. Investigation of these motifs showed that the identified EST-SSRs can be classified into 48 types that GT in dinucleotides and GCC in trinucleotides had the highest frequency. Annotation and gene ontology analysis revealed a relationship among 54 domains with the observed SSRs. Localization and characterization of such markers can help tracing the production of amino acids coded by identified repeats as shown in this study

Determination of sex and maturity in Acipenser stellatus by using ultrasonography

Knowledge of both sex and maturity stage without killing fish is important from many aspects. The establishment of accurate sex and maturity determination without external sexual dimorphism or when external characters are not developed has usually involved the use of either hormone radioimmunoassay or biopsy techniques. These methods are time and labor consuming as well as harmful to fish. Therefore, it would be economically important for caviar producing countries to develop accurate, effective and non-invasive method for determination of sex and maturity in sturgeons. Ultrasonography examination was performed to determine sex and differences between matured and immatured Acipenser stellatus. The 249 captured stellate sturgeons larger than 95 cm in length were examined with a linear transducer. Sex determination was carried out based on the differences in echogenicity and morphology of the ovaries and testes. Results of ultrasonography were confirmed at necropsy: 199 fish were female (63 matured and 136 immatured) and 50 were male (29 matured and 21 immatured). Ultrasonographic examination resulted in sex determination with 97.2% accuracy. Gonads of immature males may be difficult to discern. The speed of examination was around 30 seconds or less per fish depending on the stage of maturation of fish