CSA (ProQuest) (iki 2021 m.)

The work reports on the design of an area-efficient inductor-less low-noise CMOS trans-impedance amplifier suitable for entry-level optical time-domain reflectometers. The work suggests a novel approach for implementing a programmable-gain in capacitive feedback TIA with an independent adjustment of the low- and high-frequency behavior using the input stage biasing impedance and one of the feedback capacitors. The approach addresses a typical noise problem of fast feed-forward or resistive feedback topologies while alleviating the trade-off of the key TIA performance indicators. A more accurate amplifier model is proposed which takes into account the effects due to capacitive isolation and both biasing circuits. Further modifications to the reference design are suggested including the PMOS-based implementation of the biasing circuit to address the voltage headroom issue. The circuit was implemented using a standard 180 nm CMOS process and operates from 1.8 V supply with a drawn current of 11.7 mA.

This research developed mathematical models to optimize process performance for multiple pentagon fuzzy quality responses. Initially, each quality response was represented by a pentagon membership function. Then, the combination of optimal factor levels was obtained for each response replicate. Those optimal combinations were then used to construct pentagon regression models for each response. A pentagon fuzzy optimization model was formulated and solved to determine the combination of optimal factor levels at each element of pentagon response’s fuzzy number. Two real case studies, i.e. wire-electrical discharge machining and sputtering process, were provided for illustration. Optimal results of the two case studies revealed that the proposed procedure effectively optimized performance under uncertainty and provided larger improvement in multiple quality characteristics. In conclusion, the proposed procedure may enhance the process engineer’s knowledge about effects of uncertainty on process/product performance and help practitioners decide the proper adjustments of factor levels in order to enhance performance of electrical discharge machining and sputtering process.

In this paper, four differently shaped Wilkinson power dividers are presented by selecting the same physical length of two- section transmission lines, dual arbitrary frequency band Wilkinson power dividers can be achieved. The 2.4 GHz (WLAN) and 5.9 GHz (DSRC IEEE 802.11p) frequency bands are selected to complement the future development of multi-band, multi-standard transceivers. To improve physical separation and electrical isolation between the two output ports a parallel RLC circuit is employed. For verification, the simulated and measured performance results of dual-band Wilkinson power dividers implemented on the Rogers 4003C laminate are presented. The measurement results for the fabricated Wilkinson power dividers were in good agreement with theoretical simulation results and show dual-band characteristics.

The article deals with creative and social capital (SC) in the light of creative society. SC has both positive and negative aspects. The first are trust, economic development, ecological consciousness, etc. The latter are intolerance for certain individuals, stagnant relations, depression of the initiatives, etc. The negative aspects have been connected with the lack of creative aspirations within a social group. There is a dialectical relation between social and creative capital (CC). Although creative workers need certain support from their social environment, creativity does not only use social ties to spread creative results, but also ignores them by appealing to a new creative community. The comparison of SC and CC opens very different approaches towards society. In the case of SC, we still have the privileged classes who consolidate the whole society. Even in the case of the creative class we face the relics of (Post)Marxist economic approach if we correlate the activity of so called creative class with economic prosperity of a region. In the case of creative society, we have very different approach. If every person is more or less creative, we do not have the creative classes or parties as holders of CC any more. This (neo)liberal approach means also the dissemination of any form of capital, as well as elimination of attitude formed by economic priority in our societies.

Research background: The value of clusters in developing advanced technology products and services as well as promoting regional growth is acknowledged by many policymakers and researchers (Lee et al., 2012). Hence, clusters are identified as enablers of the circular economy and resource efficiency in this study. Companies aim to enhance competencies and create competitive advantages in global competition and this can be achieved through pulling from a common and accessible pool of resources, information and demand for innovation which means that companies can profit from belonging to a cluster. Purpose of the article: The main aim of the article is to overview the scientific literature that addresses the circular economy, identify clusters and their role in the circular economy and suggest how small and medium enterprises could engage in a circular economy through clusters' performance development. Methods: Bibliometric literature analysis enables identifying the latest trends in scientific articles regarding a circular economy and clusters. The analytical hierarchy process (AHP) allows for composing the scheme of the cluster’s competitive advantage within circular economy. Findings & Value added: The findings suggest that resource efficiency is considered to be one of the most important ambitions and clusters can work as enablers of a circular economy for small and medium enterprises (SMEs), gaining a competitive advantage at the same time. Clusters can encourage and provide conditions in which SMEs would turn to a circular economy. The scheme of Cluster's competitive advantage proposed by the author can help cluster's coordinators, policymakers and all the concerned parties to verify the importance of clusters' involvement in the circular economy.

The intensive industrial development and urbanization, as well as the negligible return of hazardous components to the deeper layers of the Earth, increases the contamination load on the noosphere (i.e., the new status of the biosphere, the development of which is mainly controlled by the conscious activity of a human being). The need for reducing the spread and mobility of contaminants is growing. The insights into the role of the tree in the reduction of contaminant mobility through its life cycle are presented to show an important function performed by the living matter and its products in reducing contamination. For maintaining the sustainable development, natural materials are often used as the media in the environmental protection technologies. However, due to increasing contamination intensity, the capacity of natural materials is not sufficiently high. Therefore, the popularity of engineered materials, such as biochar which is the thermochemically modified lignocellulosic product, is growing. The new approaches, based on using the contaminant footprint, as well as natural (biogeochemical) and engineered barriers for reducing contaminant migration and their application, are described in the paper.

The Indian textile industry is lacking in an entrepreneurial inclination of a skilled young generation; because of this, the industry is facing a challenge to achieve sustainable development and growth. To overcome this problem, the goal of this work is to build an entrepreneurial inclination model in the context of the textile industry. For achieving this goal, a combined approach of an extensive literature review and experts mining has been used to establish the entrepreneurial inclination factors in phased of the study. In the second phase, an Interpretive Structural Modelling with Matrice d'Impacts Croises Multiplication Appliques a un Classement (MICMAC) has been applied to build a structural model and to find the driving force factors and dependence power. The results show that effective entrepreneurship courses, institutional policy, training and internship, institutional corporation and the involvement of institutional heads play a very significant role in encouraging youth towards entrepreneurship. The outcomes of the study can help both the government and academic institutes to draw up effective policy and develop an entrepreneurial culture which can help to create more entrepreneurs in the textile field.

In the current paper, the main regularities in fracture of the railway axle steel have been found. It is established that the energy intensity of the steel fracture is connected with the deformational manifestations at the meso and macrolevels. As a part of the methodology of mesomechanics, the deformation behavior of the locomotive axis material has been described, taking into account the interaction between the processes that take place at different scale levels under the impact loading of Charpy specimens. A special role is given to the investigation of the local response of the material at the mesolevel, where the stress–strain state is characterized by a significant nonuniformity, and leads to the formation of shear lips. The shear lip parameters are found to be linearly and depend on the energy intensity of the impact deformation and fracture of the material. The additional evaluation parameters of the energy intensity of deformation and fracture of Charpy specimens can be tore out on the surface and micromechanisms of fracture.

Materials used for the study: Portland cement CEM I 42.5 R, 4/16 gravel, 0/4 sand. The fine aggregate in four concrete mixtures was substituted with steel cord scrap added at 1.5 %, 3.0 % and 4.5 %. Water absorption and compressive strength was measured in concrete specimens after 7 and 28 days of curing. Total, closed and open porosity was measured in the modified concrete specimens. The tests of predicted freeze-thaw cycles were done. Test results showed that the substitution of fine aggregate with steel cord scrap results in lower water absorption and higher compressive strength in the modified concrete specimens. The porosity parameters have also changed: the closed porosity has increased and consequently the freeze-thaw resistance of modified concrete has improved.