One-dimensional Numerical Analysis Research Articles

Integration of Site Effects into Probabilistic Seismic Hazard Assessment (PSHA): A Comparison between Two Fully Probabilistic Methods on the Euroseistest Site

The integration of site effects into Probabilistic Seismic Hazard Assessment (PSHA) is still an open issue within the seismic hazard community. Several approaches have been proposed varying from deterministic to fully probabilistic, through hybrid (probabilistic-deterministic) approaches. The present study compares the hazard curves that have been obtained for a thick, soft non-linear site with two different fully probabilistic, site-specific seismic hazard methods: (1) The analytical approximation of the full convolution method (AM) proposed by Bazzurro and Cornell 2004a,b and (2) what we call the Full Probabilistic Stochastic Method (SM). The AM computes the site-specific hazard curve on soil, HC(Sas(f)), by convolving for each oscillator frequency the bedrock hazard curve, HC(Sar(f)), with a simplified representation of the probability distribution of the amplification function, AF(f), at the considered site The SM hazard curve is built from stochastic time histories on soil or rock corresponding to a representative, long enough synthetic catalog of seismic events. This comparison is performed for the example case of the Euroseistest site near Thessaloniki (Greece). For this purpose, we generate a long synthetic earthquake catalog, we calculate synthetic time histories on rock with the stochastic point source approach, and then scale them using an adhoc frequency-dependent correction factor to fit the specific rock target hazard. We then propagate the rock stochastic time histories, from depth to surface using two different one-dimensional (1D) numerical site response analyses, while using an equivalent-linear (EL) and a non-linear (NL) code to account for code-to-code variability. Lastly, we compute the probability distribution of the non-linear site amplification function, AF(f), for both site response analyses, and derive the site-specific hazard curve with both AM and SM methods, to account for method-to-method variability. The code-to-code variability (EL and NL) is found to be significant, providing a much larger contribution to the uncertainty in hazard estimates, than the method-to-method variability: AM and SM results are found comparable whenever simultaneously applicable. However, the AM method is also shown to exhibit severe limitations in the case of strong non-linearity, leading to ground motion “saturation”, so that finally the SM method is to be preferred, despite its much higher computational price. Finally, we encourage the use of ground-motion simulations to integrate site effects into PSHA, since models with different levels of complexity can be included (e.g., point source, extended source, 1D, two-dimensional (2D), and three-dimensional (3D) site response analysis, kappa effect, hard rock …), and the corresponding variability of the site response can be quantified.

1-3-2 一次元簡易解析による二段噴流床ガス化炉への水蒸気添加の影響評価(Session 1-3 ガス化)

1-3-2 一次元簡易解析による二段噴流床ガス化炉への水蒸気添加の影響評価(Session 1-3 ガス化)

Study of fuel inlet temperature variations on palm biodiesel operating with a diesel engine

Biofuel includes biodiesel is introduced to overcome the air pollution problems. Biodiesel is the sustainable and alternative fuel that derived from edible and non-edible oil produced from bio-originated species, plants, and animals. This paper presents the simulation analysis on the effect of fuel temperature variations on diesel engine performance and emission using palm-biodiesel. A one-dimensional numerical analysis, Diesel RK software is used to simulate a single cylinder, four-stroke diesel engine on the performance and emission when operated at a full load condition using fuel temperature variations ranging 300 K to 333 K. Results showed that simulated results for brake power and brake torque were 0.7% each when compared to the highest and lowest fuel temperature ranging from 333 K to 300 K. Moreover, higher fuel temperature for palm biodiesel tends to produce lower exhaust gas temperature and brake specific fuel consumption at a constant engine speed of 2400 rpm. It can be concluded that from the study, fuel temperature variations of biodiesel could produce a significant effect regarding engine performance and emission that influence the driving economy of the engine.

Numerical model and simulation of a vehicular heat storage system with phase-change material

For heat storage applications designed to recover and recycle waste heat energy, it is usually advantageous to store heat in a phase-change material. One-dimensional numerical analysis and evaluation of a heat storage system that uses a phase-change material to store latent heat in addition to sensible heat was carried out, and it was found that up to 30% of the total heat energy generated by the fuel and subsequently lost to cooling can be recovered. A heat storage system was installed to reduce warm-up time by releasing heat directly into the engine coolant during cold start, and the corresponding reduction in fuel consumption was measured. With the addition of a heat storage device, the warm-up time to 95°C was reduced by between 18.1% and 27.1%. A numerical simulation of the New European Driving Cycle was carried out for a vehicle equipped with a 1.6-L diesel engine and a heat storage system. Analytical results showed that the warm-up time was reduced by 40.5% and the fuel consumption was reduced by 2.71% compared to a vehicle without a heat storage system installed.

Seismic response analysis in the southern part of the historic centre of the City of L’Aquila (Italy)

This paper deals in the 2011 extensive site investigation by means of boreholes up to a depth of 80m, Down-Hole (D-H) tests, Seismic Dilatometer Marchetti Tests (SDMT), Multichannel Analysis of Surface Waves (MASW) tests in the area of via XX Settembre of the city centre of L’Aquila (Italy), to obtain a detailed geotechnical model. Results of site investigations showed a marked variability of shear wave velocity Vs profiles, especially in the upper 5–10m, where different soil types are commonly encountered, all characterised by low values of Vs.In this paper the main features of the April 6, 2009 L’Aquila Earthquake (ML=5.8; MW=6.3) are also discussed. The earthquake caused 308 casualties and heavy damage in the city of L’Aquila and in the surroundings villages. Some accelerometric stations were located across the Aterno River Valley, while only one station (namely AQK) was located in the city centre of L’Aquila. The peak acceleration values ranged from 0.35g recorded in the city centre to 0.65g recorded in the middle Aterno valley. The recorded time histories were characterised by short durations and high peak accelerations both in the horizontal and in the vertical directions.The area of via XX Settembre (southern part of the historic centre of the city of L’Aquila) was severely damaged by the earthquake. This area, located at a very short distance from the city centre, includes also some reinforced concrete frame buildings, mostly 5–7 storey high, built between 1950 and 1965. Old masonry buildings and some of these r.c. buildings collapsed or suffered severe damage due to the main shock, causing several tens of victims. The peculiar subsoil conditions locally detected down to about 40m depths in this area include fine-grained soils interposed within, or placed above, “Brecce dell’Aquila” (typical of L’Aquila) and man-made fills. Low and variable shear wave velocity VS values in the upper portion of the subsoil have locally originated major amplification of the ground motion during the main shock.Therefore the paper deals also in specific one-dimensional numerical seismic response analyses performed. Significant amplification effects related to local subsoil conditions, bigger than the amplification factors given by the Italian Building Code NTC 2008, have been discovered by the seismic response analyses carried out at the site. The results of soil response analyses were compared with the occurred damage in the area.

태양열 담수기 다중효용부의 해수 공급유량에 관한 1차원 수치해석

다중효용 태양열 담수기에서 다중효용부 각 효용단의 해수 공급유량은 효용수 증가에 따른 열에너지 감소를 고려하여 점차 줄어드는데, 선행연구에서는 효용단 별 서로 다른 공급유량 감소율을 제시하였다. 이론적으로 열에너지 감소율이 일정하기 때문에 효용단 별 서로 다른 유량감소율은 적절하지 않다. 본 논문에서는 수치해석을 통해 다중효용부의 공급유량 감소율에 따른 담수생산량 특성을 분석하였다. 해석결과 공급에너지가 같은 조건(12MJ)에서 동일한 감소율(11%)일 때와 그렇지 않을 때의 생산량 차이는 0.56%로 거의 비슷하였다. 또한 수치해석을 통해 고온의 배기가스로부터 얻은 공급 에너지량에 따라 다중효용부 해수공급유량의 최적값을 도출하였다. 최적 유량은 에너지의 공급 형태에 따라 선형적으로 증가하거나 증가 후 평형상태에 도달하는 현상이 발생하였다.

A new rate-dependent stress-based nonlocal damage model to simulate dynamic tensile failure of quasi-brittle materials

The development of realistic numerical tools to efficiently model the response of concrete structures subjected to close-in detonations and high velocity impact has been one of the major quests in defense research. Under these loading conditions, quasi-brittle materials undergo a multitude of failure (damage) mechanisms. Dynamic tensile failure (e.g. spalling), characterized by a significant strength increase associated with loading rate, has revealed to be particularly challenging to represent.In this contribution, a rate-dependent stress-based nonlocal damage model has been introduced for the simulation of dynamic tensile failure of quasi-brittle materials. The recently proposed stress-based nonlocal criterion has been updated in order to be consistently combined with a rate-dependent version of the well-known Mazars damage model. The model was implemented in LS-DYNA using a fully explicit computational scheme.Two sets of numerical examples have been presented. First, one-dimensional numerical analyses were conducted to evaluate the model capabilities, applicability and limitations. Second, the model has been validated against experimental results. It has been shown that the proposed model, in addition to correcting spurious mesh sensitivity, also provides a more realistic representation of damage initiation and growth, in particular around discontinuities (notches and free boundaries) and damaged areas.

One-dimensional Stress Evaluation of a Ring Bulk HTS with Shrinkage Fit by an Iron Ring

The stress distributions of a ring bulk high-Tc superconductor are studied in the one-dimensional numerical analysis. Boundary condition is derivated under shrinkage fit by an iron ring. Convergences of the solutions are compared with the simple iteration method and the successive approximation method. Maximum hoop stresses are evaluated during the field-cooled magnetization. Differences of the solutions are also discussed between the present and the previous boundary conditions.

地中熱リファレンスマップの開発（IDO 法による 1 次元半径方向熱伝導解析）

地中熱リファレンスマップの開発（IDO 法による 1 次元半径方向熱伝導解析）

EFFECT OF AMBIENT TEMPERATURE ON DIESEL-ENGINE COMBUSTION CHARACTERISTICs OPERATING WITH ALCOHOL FUEL

Biofuel is an alternative fuel source for diesel engines. Nowadays, biofuel attracts more interest due to the depletion of mineral petroleum resources. The aim of this paper is to study the effect of ambient temperature on the combustion and performance of a diesel engine when using ethanol and methanol as fuels. The one-dimensional numerical analysis uses the GT-Power software program to simulate a commercial four-cylinder diesel engine. The diesel engine was simulated in order to study the characteristics of engine combustion when the engine is operating with ethanol and methanol as alternative fuels. The simulations were conducted under the full-load condition for an engine operating with diesel, ethanol, and methanol. Ambient temperatures used for each test were 30, 40, and 50 °C. The results show that the in-cylinder pressure for ethanol is higher than that of methanol and diesel at different ambient temperatures, while methanol was found to yield a higher rate of heat release compared to ethanol and diesel. However, changes in ambient temperature in the inlet pipe do not affect the rate of heat release when using any fuel. It can be concluded that biofuels are excellent fuel alternatives to replace diesel in the future. Keyword: Ambient temperature; diesel engine; ethanol, methanol; in-cylinder pressure.

Effect of nonlinear sorption on multispecies radionuclide transport in a coupled fracture-matrix system with variable fracture aperture: a numerical study

A one-dimensional numerical analysis on multispecies radionuclide transport in a single-horizontal coupled fracture-matrix system has been performed. Analysis considering linear and nonlinear adsorption cases with linear, Langmuir, and Freundlich adsorption models has been carried out. The results indicate that there is a significant change in the spatial distribution of radionuclides in a coupled fracture-matrix system when a nonlinear adsorption isotherm is considered as compared to the simplified linear sorption isotherm. Sensitivity analysis of Langmuir constant and Freundlich exponent has been performed, and the numerical results indicate that the behavior of radionuclide transport is strongly influenced by these nonlinear sorption isotherm parameters. In addition, an attempt has been made to consider the variation of fracture aperture thickness along its flow direction by introducing logarithmic distribution. A clear distinction in the spatial distribution of radionuclide concentration was observed when variable fracture aperture is considered as opposed to the conventional parallel plate model with a constant fracture aperture thickness. Further, the results suggest that there is an enhanced retardation of radionuclides within the high permeable fracture with varying fracture aperture.

울산 회야강 하구 도류제 건설에 따른 표사이동 특성

Integrated sand control including sediment discharge from hinterland rivers is necessary to maintain coastal sand resources over a long term. In this regard, the following subjects should be considered; efficient ways to transfer discharged sand from a river to the neighboring coast, measures to improve storage efficiency of the discharged sand at the river delta and/or river terrace, measures to prevent the sand resources from being discharged into the deep sea during flooding. From the 1997 to January 2004, the jetty of 156 m length was constructed the Heoya-river mouth to protect the blockade of river mouth. Several tests were carried out to investigate the characteristics of sediment transport and morphological change due to the construction of the jetty at the Heoya-river mouth. Firstly, The sand discharge from Heoya river is quantified by one-dimensional numerical analysis assuming the mixed sand of three different particle diameters. Also the numerical mode system, which predicts the sea bed changes obtained from the Bailard`s energy model(1981), was combined with the wave, wave-induced currents and sediment transport models. Then, to understand the changes to the blockade of the river mouth, several aerial photographs were compared, which showed that the changes were significant.

Combustion Characteristic of a Diesel Engine Operating with Methanol as Alternative Fuel

Modelling the compression ignition engine mostly depends on fuel characteristics. The proses involve a model of the real system and carry out experiment as a mean of comparison to understand the behaviour of the system. The diesel engine nowadays operated with different kind of alternative fuels such as natural gas and biofuel. The aim of this article is to study the combustion characteristic occurred in an engine cylinder of a diesel engine when using biofuel. The one-dimensional numerical analysis using GT-Power software is used to simulate the diesel engine. The engine operated at full engine load and difference speed. The methanol fuel used in the simulation is derived from the conventional methanol fuel properties. The analysis of simulations includes the cylinder pressure, combustion temperature and rate of heat release. The simulation result shows that in-cylinder pressure for methanol is slightly higher than diesel fuel in any speed of the engine. It also found that the combustion characteristic on methanol temperature is higher at all crank angle degree of diesel fuel. Mass fraction burns of methanol are much lower than diesel fuel, but burns faster than diesel fuel.

One-Dimensional Simulation of the Combustion Process in an Engine Cylinder with Ethanol

The diesel engine is one of the most important engines for road vehicles. The engine nowadays operates with different kinds of alternative fuels, such as natural gas and biofuel. The aim of this article is to study the combustion process that occurs in an engine cylinder of a diesel engine when using biofuel. The one-dimensional numerical analysis using GT-Power software is used to simulate the commercial four-cylinder diesel engine. The engine operated at high engine load and speed. The ethanol fuel used in the simulation is derived from the conventional ethanol fuel properties. The analysis of simulations includes the cylinder pressure, combustion temperature and rate of heat release. The simulation results show that in-cylinder pressure and temperature for ethanol is higher than for diesel at any engine speed. However, the mass fraction of ethanol burned is similar to that of diesel. MFB only affects the engine speed.

Analysis of Scattering Characteristics for 1D Electromagnetic Wave by Sudden Creation of a Plasma Slab Based on FDTD

Based on Maxwell's equations and the time-varying plasma constitutive equation, electromagnetic scattering characteristics by a sudden-created plasma slab can be analyzed. According to one-dimensional numerical analysis, a modified NPML(M-NPML) absorbing boundary condition (ABC), by which the transient plasma can be truncated, was validated. The frequency drift phenomenon for electromagnetic wave in a transient plasma slab and some other useful conclusions are obtained.

Numerical Analysis of Heat–Mass Transport and Pressure Build-Up in 1D Unsaturated Porous Medium Subjected to a Combined Microwave and Vacuum System

This article presents one-dimensional numerical analysis of heat-mass transport and pressure build-up inside an unsaturated porous media under microwave energy at a vacuum pressure condition. The unsaturated porous media is composed of glass beads, water, and air. The absorbed microwave power term is computed based on Lambert's law. The finite difference method together with Newton-Raphson technique is employed to predict the heat, multiphase flow, and pressure build-up. Based on the numerical analysis of the effects of vacuum pressure and types of dielectric materials, it was found that the vacuum pressure had a strong effect on temperature, absorbed microwave power, saturation and pressure build-up distribution, and movement of fluid inside the unsaturated porous media during the microwave drying process.

식생강화를 위한 다공성 소일 블록의 치수안정성 해석

본 연구에서는 자연친화적인 호안 블록의 현장 적용시 충분한 기술적인 검증과 구조적, 수리학적 안정성 검토 등이 제대로 이루어지지 않고 있는 문제점을 개선하기 위해 생태적 기능을 확보할 수 있는 식생강화를 위한 다공성 소일 블록에 대하여 수리적 거동 변화에 따른 수리학적 안정성을 검토하였다. 대상구간을 선정하여 수치해석 및 수리모형실험을 실시하였으며 수치해석을 위해 1차원 수치해석모형인 HEC-RAS와 2차원 수치해석모형인 RMA-2를 이용하여 1, 2차원 수치해석을 실시하였고, Froude 상사법칙을 적용하여 식생 유, 무에 따른 축척된 수리모형실험을 실시하였다. 수리모형실험의 경우 실험결과에 대한 타당성을 위해 축척된 수리모형실험의 유속 및 소류력 결과를 원형으로 환산하여 1, 2차원 수치해석결과와 동일한 조건하에 비교 검토하였고 그 결과 비교적 일치된 결과가 나타난 것으로 확인되었으며 이에 따른 원형으로 환산된 소류력 결과를 기존 연구결과인 호안의 허용소류력과 비교함으로써 블록의 수리학적 안정성을 제시하였다. In this Research, in order to improve problems of not enough technical validation and structural and hydraulic stability evaluation when nature-friendly revetment block is applied to field, hydraulic stability evaluation according to hydraulic behavior change of porosity soil block for vegetation reinforcement that secures ecological function was reviewed. By selecting object section, numerical analysis and hydraulic model experiments were performed; for numerical analysis, by using 1-dimensional numerical analysis model HEC-RAS and 2-dimensional numerical analysis RMA-2, one-dimensional(1D) and two-dimensional(2D) numerical analysis were performed; by applying Froude's similarity law, reduced-scale hydraulic model experiments according to vegetation existence were performed. In hydraulic model experiment, for validity of experiment result, the result of velocity and tractive force of reduced-scale hydraulic model experiments was converted to prototype so that it can be compared and reviewed under the same condition of one-dimensional(1D) and two-dimensional(2D) numerical analysis result; as a result, it was confirmed that comparatively united result appeared, and by comparing prototype-converted tractive force result with revetment's allowable tractive force coming from an existing research, block's hydraulic stability was suggested.

A007 One-Dimensional Numerical Analysis of Thermal Stress Propagation in Sheet Glass Generated by Pulsed Laser Irradiation

A007 One-Dimensional Numerical Analysis of Thermal Stress Propagation in Sheet Glass Generated by Pulsed Laser Irradiation

One-dimensional numerical analysis of transistor lasers

We demonstrate one-dimensional numerical analysis of transistor lasers (TLs). The high frequency performances of TLs and laser diodes (LDs) are compared. The charging time definitions of the TL and LD are given. The TL has a larger bandwidth and a shorter rise time than the LD due to the shorter charging time in the former. We find that the bandwidth decreases and the eye diagram of 40 Gb/s is degraded with increasing base region width of the TL. Finally, compared with the TL, the bandwidth reduction of LDs at high injection currents is due to a narrower small-signal response for the virtual states carrier density to the modulation current ratio.

English

This paper is presented to study the effect of temperature using 5 % biodiesel blended on diesel engine performance. The one-dimensional numerical analysis of GT-Power software is used to simulate the commercial four cylinder diesel engine. The standard fuel data base of GT-Power does not contain any biodiesel. Therefore, the authors have measured typical physical properties of the fuel before it can be installed into the GT-Power data base. The diesel engine is simulated to study the characteristic of engine performance when the engine is operating with fuel blend as an alternative fuel. The simulations are conducted at full load condition where the temperature are varies from 300K to 500K. The simulation results show that the brake power and brake torque reduced maximum of 1.39 % and 1.13 % respectively for the engine operating with fuel blend at different temperatures. It was shown that the insignificant different is due to the small gap between energy content values. The decrease in the lower heating value caused an increase in the brake specific fuel consumption thus reduces the brake thermal efficiency of engine performance at full load.