Surface Texturing Technique Based on Ultrasonic Turning for Improving Tribological Properties

Tribological properties such as lubrication, friction, and wear resistance greatly affect machine operation efficiency, performance, and service life. Surface texturing methods such as scraping can be used to improve these properties. Scraping creates many small depressions on the target surface. These depressions, which are evenly distributed, function as oil holes and thus improve lubrication performance. This paper describes a surface texturing technique based on ultrasonic vibration-assisted turning (UVAT) that simultaneously improves tribological properties and machinability. In UVAT, the cutting tool is oscillated mainly in the principal direction. Vibration in the radial direction, which is induced by Poisson deformation, periodically digs up or pushes the workpiece surface in the radial direction, creating a textured surface. A surface subjected to UVAT has periodic depressions along the workpiece rotation direction. The texturing rate of UVAT is up to 6700 mm2/min, which is higher than that of manual scraping. To evaluate the tribological performance of a surface textured by UVAT, the friction coefficient between a stainless steel pin and the surface was measured under oil dipping conditions. The results of friction experiments show that the friction coefficient of the UVAT-treated surface and its fluctuation were lower than those of a conventional turned surface. The UVAT-treated surface had stable friction properties.

Analysis of the efficiency of insurance companies in Indonesia

Financial system stability is not only supported by the banking sector, but also the role of insurance companies that operate efficiently. The study aims to analyze the efficiency performance of general insurance companies using two stages of data envelopment analysis during the 2017 – 2018 period. The first stage of efficiency measurement using a non-parametric data envelopment analysis (DEA) approach shows the efficiency level of general insurance companies experiencing a positive trend. The performance of general insurance companies in 2018 was more efficient than in 2017 based on the value of technical efficiency (CRS) and the value of pure technical efficiency (VRS). This means that in general there has been an increase in the efficiency of general insurance companies in Indonesia from 2017 to 2018. Testing the efficiency determinants in the second stage using the Tobit regression model found that the cost ratio is the only factor that significantly influences the efficiency level of general insurance companies in Indonesia. Meanwhile, company ownership and investment adequacy ratio have no significant effect on the efficiency level of general insurance companies in Indonesia. The results of the study provide recommendations to the management of general insurance companies that efficiency performance has not reached the maximum, and to improve it, it is necessary to control costs without disturbing routine operations and development activities.

Formal Verification of ZigBee-Based Routing Protocol for Smart Grids

Smart grids provide a digital upgradation of the conventional power grids by alleviating the power outages and voltage sags that occur due to their inefficient communication technologies and systems. They mainly tend to strengthen the efficiency, performance, and reliability of the traditional grids by establishing a trusted communication link between their different components through routing protocols. The conventional methods, i.e., the computer-based simulations and net testing, for analyzing these routing network protocols are error-prone and thus cannot be relied upon while analyzing the safety-critical smart grid systems. Formal methods can cater for the above-mentioned inaccuracies and thus can be very beneficial in analyzing communication protocols used in smart grids. In order to demonstrate the utilization and effectiveness of formal methods in analyzing smart grid routing protocols, we use the UPPAAL model checker to formally model the ZigBee-based routing protocol. We also verify some of its properties, such as, liveness, collision avoidance and deadlock freeness.

A Literature Review on the Relatiohship between Competition and Efficiency for Takaful and Conventional Insurance

When there are many players operate in a particular market, it encourages competition. Thus, healthy competition in the market leads to efficiency performance. Takaful and conventional insurance are the two parallel methods used to transact insurance business. The emergence of the Takaful market has contributed to competitiveness and conventional insurance is facing competition with Takaful. Therefore, this paper attempts to review the literatures relating to the relationship between competition and efficiency between Takaful and conventional and whether there exist a positive or a negative relationship.

Desporto Universitário em Portugal: novas perguntas e novas possibilidades (Deporte Universitario en Portugal: Nuevas preguntas y nuevas posibilidades) (University Sports in Portugal: new questions and new possibilities)

O desporto universitário tem merecido uma particular atenção por parte de educadores e investigadores, tanto nacionalmente como internacionalmente, na medida que o desporto universitário é uma atividade que para além da sua missão desportiva (e.g., competitiva, cooperativa) tem também (deveria ter) uma missão social, axiológica e cultural. No entanto a análise empírica e investigativa parece demonstrar que o desporto universitário está muito ancorado na dimensão competitiva (i.e., práxis competitiva preocupada com o resultado, a eficácia, o rendimento), “esquecendo” as outras dimensões/missões. Neste contexto parece ser necessário aprofundar as especificidades do desporto universitário, nomeadamente os seus quadros organizativos e praxiológicos que levem a “bom porto” todas as dimensões que encerra e não apenas algumas. Face a estas constatações, este artigo tem como objetivo contribuir para a reflexão do significado, da importância e das possíveis intervenções (novas práxis) do desporto universitário, tentando apresentar, para tal, possíveis caminhos no sentido da promoção de um desporto universitário total na sua radicalidade humana. Resumen. El deporte universitario ha recibido especial atención por parte de educadores e investigadores tanto a nivel nacional como internacional, ya que el deporte universitario es una actividad que además de su misión deportiva (por ejemplo, competitiva, cooperativa) también tiene (debe tener) una misión social, axiológica y cultural. Sin embargo, el análisis empírico e investigativo parece demostrar que el deporte universitario está muy anclado en la dimensión competitiva (i.e., praxis competitiva preocupada por el resultado, efectividad, rendimiento), “olvidando” las otras dimensiones / misiones. En este contexto, parece necesario profundizar en las especificidades del deporte universitario, es decir, en sus marcos organizativos y praxiológicos que llevan al “buen puerto” todas las dimensiones que encierra y no solo algunas. Ante estos hallazgos, el texto que presentamos pretende contribuir a la reflexión sobre el significado, la importancia y las posibles intervenciones (nuevas praxis) del deporte universitario, tratando de presentar, para ello, posibles caminos hacia la promoción de un deporte universitario total en su radicalismo humano. Abstract. University sport has deserved particular attention from educators and researchers, both nationally and internationally, as university sport is an activity that, in addition to its sporting mission (eg, competitive, cooperative) also has (should have) a social, axiological and cultural mission. However, empirical and investigative analysis seems to demonstrate that university sport is very much anchored in the competitive dimension (i.e., competitive praxis concerned with results, efficiency, performance), “forgetting” the other dimensions/missions. In this context, it seems to be necessary to deepen the specifics of university sport, namely its organizational and praxiological frameworks that lead to a “good port” for all the dimensions it encompasses and not just a few. Given these findings, this article aims to contribute to the reflection of the meaning, importance and possible interventions (new praxis) of university sport, trying to present, for this purpose, possible paths towards the promotion of a total university sport in its human radicality.

Revenue efficiency evaluation of life insurance companies in India: identification of leaders and laggards

PurposeThe purpose of this article is to evaluate revenue efficiency performance of life insurance companies in India. The study also compares if private or public insurance sector is more “revenue efficient”. Furthermore, the study determines the nature of return to scale (RTS) and identifies the leaders and laggards amongst insurance companies operating in India.Design/methodology/approachRevenue efficiency is calculated by employing data envelopment analysis – a non-parametric approach, on a data set of 24 insurance companies over the period 2013–2014 to 2017–2018.FindingsThe empirical results suggest that life insurance companies in India could generate only 34.4% of revenue, which is very less than what these are expected to generate from the same inputs. Majority of life insurance companies operating in India are operating at decreasing return to scale (DRS). There is a reduction in leaders and the highest proportion of companies is falling in the category of laggards.Originality/valueAs per the best knowledge of researchers, no empirical work has been carried out with respect to measuring the revenue efficiency of Indian insurance companies. The current study appropriately fills the gap by not only calculating the revenue efficiency scores of insurance companies in India but also provides insights into the causes of revenue inefficiencies. It also gives implications for efficient and effective management of insurance companies.

Performance of Flushing Efficiency of Sediment Evacuation from Wlingi and Lodoyo Reservoirs

The sediment evacuation from the reservoir should be carried out when it disturbs the dam development’s functional design. There are issues regarding the objection to releasing sediment from the reservoir, especially related to potential environmental degradation of the river downstream. The sediment source entering the reservoirs is considerably variable, depending upon the catchment characteristics and the hydrological triggers. When limiting the erosion yield and controlling the sediment in the catchment, evacuating sediment from the reservoir could be the only alternative to avoid environmental degradation. Several issues showed that sediment evacuation from reservoirs is a cost-effective solution. Therefore, assessing the efficiency of sediment evacuation from a reservoir through flushing has become of high interest. This paper presents the analysis of the flushing efficiency performance of the flushing operation of Wlingi and Lodoyo Reservoir that was carried out on 10-17 March 2019. The flushing efficiencies are found to be 0.005 and 0.003 for Wlingi and Lodoyo Reservoirs, respectively. These figures are lower than that of Mrica Reservoir and other world reservoirs at higher than 0.1. Further analysis suggests the critical timing of the sediment evacuation schedule considering the inflow condition.