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Chinese Physics B 2015年第3期24卷 48-54页

作者： Ade Kurniawan A.Suparmi C.Cari Physics Department Sebelas Maret University

An approximate solution of the Dirac equation for a spin-1/2 particle under the influence of q-deformed hyperbolic P ¨oschl–Teller potential combined with trigonometric Scarf II non-central potential is studied analytically. It is assumed that the scalar potential equals the vector potential in order to obtain analytical solutions. Both radial and angular parts of the Dirac equation are solved using the Nikiforov–Uvarov method. A relativistic energy spectrum and the relation between quantum numbers can be obtained using this method. Several quantum wave functions corresponding to several states are also presented in terms of the Jacobi Polynomials.

关键词： Dirac equation q-deformed hyperbolic function Poschl–Teller potential trigonometric Scarf II potential

Experimental study of the effect of slotted blades on the Savonius wind turbine performance

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Theoretical & Applied Mechanics Letters 2021年第3期11卷 162-171页

作者： Dominicus Danardono Dwi Prija Tjahjana Zainal Arifin Suyitno Suyitno Wibawa Endra Juwana Aditya Rio Prabowo Catur Harsito Department of Mechanical Engineering Universitas Sebelas MaretSurakartaIndonesia Vocational School of Mechanical Engineering Universitas Sebelas MaretSurakartaIndonesia

This study investigates the effect of Reynolds number on the performance of Savonius wind turbine with slotted *** turbine performance investigation was based on the torque coefficient(Ct),power coefficient(Cp),and tip speed ratio(TSR).The experiment used two number of blade configuration,blade overlap ratio of 10%,12.5%and 20%,slotted position of 15%,20%,25%and 35%,and also slotted gap width of 3 mm,5 mm,7 mm,and 9 *** wind speed carried out in this experiment are 5.94 m/s,6.46 m/s,6.99 m/s,and 7.27 m/s,which are generated from the fan blowers as a wind *** Savonius turbine with 10%overlap ratio shows the best *** highest Cp obtained is 0.138 by the variation of a 3 mm gap with Re of 1.44×10^(4) and 0.526 TSR.

关键词： Reynolds number Slotted blades Savonius wind turbine

Inventory and sales decisions in a vendor–buyer system with imperfect items and learning in inspection

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Journal of Control and Decision 2021年第4期8卷 453-463页

作者： Wakhid Ahmad Jauhari Diah Ayu Purnasari Cucuk Nur Rosyidi Department of Industrial Engineering Universitas Sebelas MaretSurakartaIndonesia

In this study,we propose a joint economic lot-sizing model to include learning process along with errors in inspection and full backordering *** aim to study pricing and inventory decisions in a two-level supply chain involving a single vendor and a single buyer in which the demand is sensitive to price and company’s advertisement *** mathematical inventory model is developed analytically and solved using a proposed *** objective of the model is to maximise joint total profit by simultaneously determining optimal shipment size,number of deliveries,backorder quantity and product selling price.A numerical example is provided to show the application of the model and to investigate the impact of key parameter’s changes on model *** comparing the integrated/centralised model to the independent/decentralised model,we note that the integrated/centralised model provides better profit to the system,along with lower selling price and smaller amount of backorder.

关键词： Lot sizing inventory model supply chain learning inspection error sensitive demand full backorder

Solution of Dirac equation for Eckart potential and trigonometric Manning Rosen potential using asymptotic iteration method

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Chinese Physics B 2016年第1期25卷 428-435页

作者： resita arum sari a suparmi c cari Physics Department Sebelas Maret UniversityJ1.Ir.Sutami 36A Kentingan Surakarta 57126Indonesia

The Dirac equation for Eckart potential and trigonometric Manning Rosen potential with exact spin symmetry is obtained using an asymptotic iteration method. The combination of the two potentials is substituted into the Dirac equation, then the variables are separated into radial and angular parts. The Dirac equation is solved by using an asymptotic iteration method that can reduce the second order differential equation into a differential equation with substitution variables of hypergeometry type. The relativistic energy is calculated using Matlab 2011. This study is limited to the case of spin symmetry. With the asymptotic iteration method, the energy spectra of the relativistic equations and equations of orbital quantum number l can be obtained, where both are interrelated between quantum numbers. The energy spectrum is also numerically solved using the Matlab software, where the increase in the radial quantum number nr causes the energy to decrease. The radial part and the angular part of the wave function are defined as hypergeometry functions and visualized with Matlab 2011. The results show that the disturbance of a combination of the Eckart potential and trigonometric Manning Rosen potential can change the radial part and the angular part of the wave function.

关键词： Dirac equation Eckart potential trigonometric Manning Rosen potential spin symmetric

Life cycle analysis of palm kernel shell gasification for supplying heat to an asphalt mixing plant

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Waste Disposal and Sustainable Energy 2020年第1期2卷 55-63页

作者： Sunu Herwi Pranolo Prabang Setyono Muhammad Akvis Fauzi Study Program of Chemical Engineering Faculty of EngineeringUniversitas Sebelas MaretSurakartaIndonesia Magister Study Program of Environmental Science PostgraduateUniversitas Sebelas MaretSurakartaIndonesia

The Government of the Republic of Indonesia states that the thermal energy for hot-mixed asphalt production shall be supplied by the direct combustion of fossil fuels in the form of diesel oil,natural gas,or fuel gas from coal gasification which may generate GHG *** are able to substitute the fossil fuels through gasification *** converts the biomass using limited air into gaseous fuel containing mainly CO and H_(2) that are subsequently combusted to produce heat,carbon dioxide,and *** is obvious that the CO_(2) is then absorbed by the plants for photosynthesis,main-taining a balanced closed *** study examines the level of global warming potential of this system for supplying heat based on the openLCA v1.9 *** analysis used a gate-to-gate approach to evaluate scenarios of shell gasification to produce 1 metric tonne of hot-mixed *** scope covers raw material supply and transportation,palm kernel shell gasification,and *** evaluation concludes that gasification could potentially reduce CO_(2) *** impact analysis and interpretation of the results using the openLCA database of Traci 2.1 recommend that greater CO_(2) emis-sion reduction is possible using palm kernel shell gasification,not only for supplying heat but also for electricity generation to operate all electrical equipments.

关键词： Global warming Gasification Palm kernel shell Life cycle analysis Hot-mixed asphalt

Exact solution of Dirac equation for Scarf potential with new tensor coupling potential for spin and pseudospin symmetries using Romanovski polynomials

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Chinese Physics B 2014年第9期23卷 71-80页

作者： A.Suparmi C.Cari U.A.Deta Physics Department Faculty of Mathematics and Natural ScienceSebelas Maret University Department of Physics Faculty of Mathematics and Natural ScienceState University of Surabaya

The bound state solutions of Dirac equations for a trigonometric Scarf potential with a new tensor potential under spin and pseudospin symmetry limits are investigated using Romanovski polynomials. The proposed new tensor potential is inspired by superpotential form in supersymmetric （SUSY） quantum mechanics. The Dirac equations with trigonometric Scarf potential coupled by a new tensor potential for the pseudospin and spin symmetries reduce to Schrtdinger-type equations with a shape invariant potential since the proposed new tensor potential is similar to the superpotential of trigonometric Scarf potential. The relativistic wave functions are exactly obtained in terms of Romanovski polynomials and the relativistic energy equations are also exactly obtained in the approximation scheme of centrifugal term. The new tensor potential removes the degeneracies both for pseudospin and spin symmetries.

关键词： Scarf potential new tensor potential spin and pseudospin symmetries Romanovski polynomials

Investigation on Savonius turbine technology as harvesting instrument of non-fossil energy: Technical development and potential implementation

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Theoretical & Applied Mechanics Letters 2020年第4期10卷 262-269页

作者： Aditya Rio Prabowo Dandun Mahesa Prabowoputra Department of Mechanical Engineering Universitas Sebelas MaretSurakarta 57126Indonesia Graduate School of Mechanical Engineering Universitas Sebelas MaretSurakarta 57126Indonesia

Environmental risk due to excessive residual emission is rising. Greenhouse effect, ice melting in the Arctic, reduction of air quality are several concerns which need immediate development and change. Energy harvesting equipment is one of the key solutions. Environment potential, e.g. water resource can be collaborated with mechanical equipment to harvest clean energy. Savonius turbine has been proposed and studied for this purpose and can be placed on several energy resources, i.e. water and wind. Still, real-world implementation of this technology is lacking,especially in tropical archipelago countries which have abundant water resources. In this work,assessment of Savonius turbine technology as instrument to harvest clean energy is conducted. A series of development on the turbine performance and technical modification is considered as reference to implement the technology in water and open air environments. It is noted that rotor design, operation depth and nozzle attachment are several key influencing factors.

关键词： Savonius turbine Environment pollution Revenue cost Water operation Wind-energy harvest

Micromechanical analysis on tensile properties prediction of discontinuous randomized zalacca fibre/high-density polyethylene composites under critical fibre length

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Theoretical & Applied Mechanics Letters 2020年第1期10卷 57-65页

作者： Dody Ariawan Eko Surojo Joko Triyono Ibrahim Fadli Purbayanto Agil Fitri Pamungkas Aditya Rio Prabowo Department of Mechanical Engineering Universitas Sebelas MaretSurakarta 57126Indonesia

In this research,the tensile properties'performance of compression moulded discontinuous randomized zalacca fibre/high-density polyethylene under critical fibre length was analysed by means of experimental method and micromechanical *** investigations were used to verify the tensile properties models toward the effect of fibre length and volume fraction on the *** experimental results showed that the tensile properties of composites had significantly increased due to the enhancement of fibre *** the contrary,a decline in the tensile properties was observed with the increase of volume fraction.A comparison was made between the available experimental results and the performances of Tsai-Pagano,Christensen and Cox-Krechel models in their prediction of composites elastic *** results showed that the consideration of fibre's elastic anisotropy in the Cox-Krenchel model had yielded a good prediction of the composites modulus,nevertheless the models could not accurately predict the composites modulus for fibre length study.

关键词： Zalacca fibre Micromechanical analysis High-density polyethylene Critical fibre length Tensile properties

The Use of Single-Phase Immersion Cooling by Using Two Types of Dielectric Fluid for Data Center Energy Savings

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Energy Engineering 2022年第1期119卷 275-286页

作者： Nugroho Agung Pambudi Awibi Muhamad Yusuf Alfan Sarifudin Energy and Society Laboratory Mechanical Engineering EducationUniversitas Sebelas MaretSurakarta57126Indonesia

Data centers are recognized as one of the most important aspects of the fourth industrial revolution since conventional data centers are inefficient and have dependency on high energy consumption,in which the cooling is responsible for 40%of the ***,this research proposes the immersion cooling method to solving the high energy consumption of data centers by cooling its component using two types of dielectric *** stages of experimentalmethods are used,such as fluid types,cooling effectiveness,optimization,and ***,benchmark software is used to measure the CPU maximum work with the temperature data performed for 24 *** results of this study show that the immersion cooling reduces 13℃ lower temperature than the conventional cooling method which means it saves more energy consumption in the data *** most optimum variable used to decrease the temperature is 1.5 lpm of flow rate and 800 rpm of fan ***,the cooling performance of the dielectric fluids shows that the mineral oil(MO)is better than the virgin coconut oil(VCO).In durability experiment,there are no components damage after five months immersed in the fluid.

关键词： Single-phase immersion cooling data center dielectric fluid mineral oil virgin coconut oil

Upgrading the Quality of Solid Fuel Made from Nyamplung (Calophyllum inophyllum) Wastes Using Hydrothermal Carbonization Treatment

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Energy Engineering 2021年第1期118卷 189-197页

作者： Riina Syivarulli Nugroho Agung Pambudi Mochamad Syamsiro Lip Huat Saw Graduate Program of Vocational Teacher Education Sebelas Maret UniversitySurakarta57126Indonesia Department of Mechanical Engineering Education Sebelas Maret UniversitySurakarta57126Indonesia Department of Mechanical Engineering Janabadra UniversityYogyakarta55231Indonesia Lee Kong Chian Faculty of Engineering and Science UTARKajang43000Malaysia

One of the major problems faced in managing biomass waste to higher quality products is choosing the right *** are used as an alternative fuel,with increase in the calorific *** carbonization(HTC)is a biomass conversion technology,used to obtain solid *** study aims to utilize of Calophyllum inophyllum as an alternative solid fuel through *** calorific value and proximate of the hydrochar will be determined and analyzed to find out its *** experiments were carried out at temperature variations of 160℃,190℃,and 220℃ and holding times of 30 and 60 *** results show that an increase in temperature and holding time causes a decline in the moisture content 1.87%,volatile matter 54.03%,and ash content 12.35%,respectively,leading to elevations in the fixed carbon at 31.75%.In addition,the highest calorific value of 4149 Kcal/Kg was produced at a temperature of 220℃,within a holding time of 60 *** results showed a significant increase in the quality of solid fuels between 3500–4611 Kcal/Kg in accordance with the American Standard Testing and Materials(ASTM).Therefore,this research leads to an important finding that Calophyllum inophyllum waste through the HTC process can be used as an alternative fuel to substitute lignite coal,which is environmentally friendly.

关键词： Hydrothermal carbonization solid fuel Calophyllum inophyllum Nyamplung