Positioning Performance of a Sub-Arc-Second Micro-Drive Rotary System

In the macro/micro dual-drive rotary system, the micro-drive system compensates for the position error of the macro-drive system. To realize the sub-arc-second (i.e., level of 1″–0.1″) positioning of the macro/micro dual-drive rotary system, it is necessary to study the positioning performance of the sub-arc-second micro-drive rotary system. In this paper, we designed a sub-arc-second micro-drive rotary system consisting of a PZT (piezoelectric actuator) and a micro rotary mechanism, and used simulation and experimental methods to study the positioning performance of the system. First, the micro-drive rotary system was developed to provide ultra-precise rotary motion. In this system, the PZT has ultrahigh resolution at a level of 0.1 nanometers in linear motion; a micro rotating mechanism was designed according to the composite motion principle of the flexible hinge, which could transform the linear motion of piezoelectric ceramics into rotating motion accurately. Second, the drive performance was analyzed based on the drive performance experiment. Third, kinematics, simulation, and experiments were carried out to analyze the transformation performance of the system. Finally, the positioning performance equation of the system was established based on the two performance equations, and the maximum rotary displacements and positioning error of the system were calculated. The study results showed that the system can provide precision motion at the sub-arc-second and good linearity of motion. This study has a certain reference value in ultra-precision positioning and micromachining for research on rotary motion systems at the sub-arc-second level.

Optimal Inflow Performance Relationship Equation for Horizontal and Deviated Wells in Low-Permeability Reservoirs

After Vogel proposed a dimensionless inflow performance equation, with the rise of the horizontal well production mode, a large number of inflow performance relationship (IPR) equations have emerged. In the productivity analysis of deviated and horizontal wells, the IPR equation proposed by Cheng is mainly used. However, it is still unclear whether these inflow performance models (such as the Cheng, Klins-Majcher, Bendakhlia-Aziz, and Wiggins-Russell-Jennings types) are suitable for productivity evaluations of horizontal and deviated wells in low-permeability reservoirs. In-depth comparisons and analyses have not been carried out, which hinders improvements in the accuracy of the productivity evaluations of horizontal wells in low-permeability reservoirs. In this study, exploratory work was conducted in two areas. First, the linear flow function relationship used in previous studies was improved. Based on the experimental pressure-volume-temperature results, a power exponential flow function model was established according to different intervals greater or less than the bubble point pressure, which was introduced into the subsequent derivation of the inflow performance equation. Second, given the particularity of low-permeability reservoir percolation, considering that the reservoir is a deformation medium, and because of the existence of a threshold pressure gradient in fluid flow, the relationship between permeability and pressure was changed. The starting pressure gradient was introduced into the subsequent establishment of the inflow performance equation. Based on the above two aspects of this work, the dimensionless IPR of single-phase and oil-gas two-phase horizontal wells in a deformed medium reservoir was established by using the equivalent seepage resistance method and complex potential superposition principle. Furthermore, through regression and error analyses of the standard inflow performance data, the correlation coefficients and error distributions of six types of IPR equations applicable to deviated and horizontal wells at different inclination angles were compared. The results show that the IPR equation established in this study features good stability and accuracy and that it can fully reflect the particularity of low-permeability reservoir seepage. It provides the best choice of the IPR between inclined wells and horizontal wells in low-permeability reservoirs. The other types of IPR equations are the Wiggins-Russell-Jennings, Klins-Majcher, Vogel, Fetkovich, Bendakhlia-Aziz, and Harrison equations, listed here in order from good to poor in accuracy.

Managerial Discretion: The Relationship Between Investments in R & D and Performance -Revisited: Case of Tunisian Enterprises

This article proposes a re-reading of the role of R & D investments in the performance equation when a manifestation of an opportunistic inclination on the part of managers occurs. Often, the manager and the owners express different expectations regarding investment choices in R & D. Although shareholders are looking for performance, the manager sometimes has a tendency to broaden his managerial discretion. The choice of R & D investments could thus reinforce managerial entrenchment. We will demonstrate the moderation exercised by managerial discretion on the R & D / Performance relationship.Our empirical validation will be put to examination against the Tunisian context by deploying various tests. We come to grips with the characteristics of the Tunisian context through an empirical study of 75 companies observed over a 7 -year time lapse, i.e. from 2008 to 2014. The explanatory analysis was an opportunity to highlight the existence of a moderation exercised over the main relationship dealt with.

Methodology for Determination of the Structural Layer Coefficient of Unbound Base Materials in Florida

The main goal of this study was to assess methodologies for the determination of base structural layer coefficients (SLCs) in Florida base materials. The aim was to streamline the traditional empirical and observationally based technique for determining layer coefficients either by an accelerated loading process or by the computer simulation of pavement performance. The paper describes a methodology in which the structural numbers (SN) of two paired test sections are used to backcalculate the unknown SLC. The SNs are determined from the AASHTO performance equation using a prediction of pavement performance from the University of Florida top-down cracking (TDC) model. The paper presents a positive application of the methodology for two test sections in Louisiana and two sections in Florida.

Implications of Financial Intermediation on The Performance of Commercial Banks in Nigeria: 2000-2017

The paper examined the arguments and counterarguments within the scientific discussion on Financial Intermediation and the performance of Commercial banks in Nigeria. Despite a series of reforms and restructuring aimed at enhancing the bank’s ability to provide services effectively, establish branch networks and finance the real sector, there is still insufficient domestic credit to commercial real-estate banks, affecting the success of financial intermediation in the Nigerian commercial banking sector. The main purpose of this study is to examine the impact of financial intermediation on the performance of commercial banks in Nigeria. The data came from a statistical bulletin of the Central Bank of Nigeria. A systematic literary approach to data analysis is regression analysis. In Equation 1, it was found that there is a significant relationship between total lending and the commercial bank lending rate in Nigeria. In Equation 2, it was found that there is a significant relationship between the overall credit ratio and the cash reserve in the commercial banks of Nigeria. In the commercial bank performance equation, it was found that there is a significant relationship between the total assets and the capital involved by commercial banks in Nigeria. In the commercial bank performance equation, it was found that there was no significant relationship between the loan and deposit ratio and the liquidity ratio in the commercial banks of Nigeria. It has also been found in Commercial Banking Performance Equation 5 that there is a significant relationship between gross domestic product and total credit in the commercial banks of Nigeria. Thus, the study authors recommend reducing the commercial bank loan rate so that investors see commercial banks as the number one source of funding, the Central Bank of Nigeria should increase the commercial banks’ minimum reserve in order to facilitate adequate lending to commercial customers by clients/investors. Commercial banks need to make effective use of the capital used to increase profitability. Commercial banks should help increase liquidity to increase their ability to cover customer withdrawals and increase loans and advances to customers. Commercial banks should allocate proper credit to the real sector for productive purposes in order to increase gross domestic product. Keywords: Financial Intermediation, Commercial Banks, Gross Domestic Product, Commercial Bank Credit.

Analisa Pembangkit Listrik Tenaga Diesel Gas Dengan Menggunakan Bahan Bakar LNG Dan Minyak Solar Di PT Indonesia Power Unit Pembangkitan Bali

Permintaan energi listrik mengalami peningkatan, seiring peningkatan pertumbuhan populasi penduduk dan banyaknya industri. Tingginya permintaan energi listrik menjadi sebuah tantangan untuk produsen listrik, dalam memenuhi kebutuhan pelanggan akan energi listrik. Produsen listrik terbesar di Bali adalah PT. Indonesia Power UP Bali. Pembangkit yang dimiliki yaitu PLTDG dengan kapasitas produksi listrik 200 MW dioperasikan menggunakan bahan bakar gas LNG dan minyak solar (HSD/LFO). Dikarenakan penggunaan minyak solar dibatasi, maka PLTDG dioperasikan dengan gas LNG. Perbedaan bahan bakar yang digunakan mempengaruhi unjuk kerja dari pembangkit. Analisa unjuk kerja memberi gambaran dalam sisi keteknikan dan analisa BPP pembangkitan memberi gambaran dalam sisi keekonomian. Penelitaian ini dilakukan dengan cara perhitungan menggunakan persamaan-persamaan unjuk kerja mesin diesel, kemudian dibandingkan unjuk kerja PLTDG menggunakan bahan bakar LNG dan minyak solar dan dianalisa secara keekonomian. Hasil yang didapat yaitu unjuk kerja PLTDG menggunakan minyak solar lebih besar tetapi dari sisi keekonomian hasil BPP PLTDG menggunakan gas LNG lebih ekonomis. Demand for electric energy has increased, as population growth increases and the number of industries. The high demand for electrical energy becomes a challenge for electricity producers, in meeting the needs of customers for electrical energy. The largest power producer in Bali is PT. Indonesia Power UP Bali. The power plant owned by PLTDG with 200 MW electricity production capacity is operated using LNG gas and diesel fuel (HSD/LFO). Due to the use of diesel fuel is limited, the PLTDG is operated with LNG gas. The difference in fuel used affects the performance of the plant. Performance analysis gives an overview in terms of engineering and BPP analysis provides an overview of the economy side. This research is done by calculation using diesel engine performance equation, and then compared the performance of PLTDG using LNG and diesel fuel and analyzed economically. The results obtained are the performance of diesel powered PLTDG larger but in terms of economics of BPP PLTDG results using LNG gas is more economical.