Kemauan Membayar (Willingness to Pay) Calon Penumpang Terhadap Rencana Pelayanan Transjogja Rute Yogyakarta-kaliurang

TransJogja is a public bus system that serves Yogyakarta city and its vicinity using mid-sized air conditioned buses. The system, that was introduced in February 2008, currently runs daily from 05.30 to 21.30 on it 4 trunk routes. Recently, a plan of opening some feeder routes has been considered to expand its service coverage so as to include potential trip generator regions, including areas along Yogyakarta – Kaliurang road. The purpose of this study was twofold, i.e. to investigate prospective passengers\u27 willingness to pay (WTP) TransJogja service planned to run Yogyakarta – Kaliurang route and to study which factors that likely determine the formation of passengers\u27 WTP. Stated preference technique was used to collect prospective passengers\u27 opinion on the price that they would pay provided certain service characteristics. In a view that one\u27s WTP may also be influenced by his/her own socioeconomic background in addition to the service features offered, respondents\u27 socioeconomic information such as age, gender, income level, etc. were also collected and used to study their influence to the stated price to pay. Based on 655 observations, a majority of 26,1% respondents stated 3.000 rupiahs as the price they would pay for Yogyakarta-Kaliurang TransJogja services, while another 23,97% stated 2.000 rupiahs. These prices correspond to various combinations of service features, including varied seating capacity, inclusion or exclusion of air conditioning system (AC), bus stops, varied peak and off-peak headway, varied service hours, and application of special rates for students. Further study using multiple linear regression method indicated that respondents\u27 socioeconomic features that include one\u27s gender, age, place of stay (along Kaliurang Rd or otherwise), and monthly transportation-related expenditure had a greater share in determining his/her WTP, rather than service features that include seating capacity, AC, and student\u27s special rate. Therefore, it was recommended that the concerned office should take consumers\u27 socioeconomic factors into consideration in their future decision on passenger tariff should the Yogyakarta-Kaliurang route of TransJogja services is to open

Anomalies in the Flow over Projectile with Wrap-around Fins

This paper presents the results of a numerical study to understand the flow field over a projectile with wraparoundfins. This investigation is performed in order to determine aerodynamic coefficients for the missile model for varying Mach number from 1.2 to 2.5. The roll moment coefficients were computed from the flow field solution and compared with other computational models and experimental works. The results show a reversal of the rolling moment in a Mach number from 1.2 to 1.4. While generating Mach number profile along missile body, a transition from subsonic to supersonic flow was notably found just before the fin-tip in the Mach number range from 1.2 to 1.4. This transition from subsonic to supersonic just before the fin seems to be the main cause for the roll reversal, which makes the flow inside the fin passage behave differently. Furthermore, it was seen that most of the effect was confined towards the leading edge of the fins.Defence Science Journal, 2009, 59(5), pp.471-484, DOI:http://dx.doi.org/10.14429/dsj.59.154

Estimation of Drag Coefficient from Radar-tracked Flight Data of a Cargo Shell

Two schemes to extract drag coefficient (C,) by processing the radar-tracked trajectories of artillery shell in motion, have been proposed. Flight trajectories of artillery shell are considered. The proposed schemes are applied on the radar-tracked trajectory data of artillery shell to estimate thc C,,. The C,, is strong function of Mach number. To capturc the functional rclationship between the C, and the Mach number, the C, of the ammunition was assumed to be a polynomial function of Mach number (separately for subsonic and supersonic). The coefficients of the assumed polynomial were estimated by minimising the error between measured and estimated trajectories. In the second scheme, whole trajectory was split into diffcrent sets containing 50 or 100 data points. Each data set was processed using the proposed schemes to estimate numerical values of C, corresponding to the average Mach number of the chosen data set. The estimated values of the C, (at different Mach numbers) have been presented along with its standard deviations. The difticulties encountered in processing the real trajectory data using the proposed schemes are also highlighted. It is observed that thc proposed schclnes could advantageously be applied to quickly estimate the numerical values of the C, at corresponding Mach numbers, by processing thc trajectory data of an artillcry shell in motion

Online Software Copyright Protection Using Trust Platform Module and Database Watermarking

As the digital information can be copied and transmitted easily, new and novel methods for the investment safeguarding are highly important. Many software companies developed several ways to prevent their software from piracy but hackers are still working. Other companies have their own techniques, but they keep them for confidential. This paper utilizes the digital watermarking and the Trust Platform Module (TPM) to enhance software piracy protection and decrease the efforts costs to protect software copyrights. The paper conducts a new approach called Trust Platform Module and Database Watermarking (TPMDWM) which is developed to enhance the software copyright protection. The proposed approach combines the new technologies of Trust Platform Module with database watermarking, hash function, and advanced encryption standard to enhance software copyright protection and decrease the cost and loose of software revenues. As shown by results, TPMDWM can effectively prevent illegal copying, getting the software at installation or updating license. The results also show that TPMDWM approach does not affect the software code and control. In addition, TPMDWM decreases dongle cost and it can also be used for client identification

Operation of an auto-initiated pulsed plasma thruster

10.1108/00022661011053373Aircraft Engineering and Aerospace Technology82283-90AATE

Numerical Modelling of Droplet Evaporation with Convection for N-Alkanes and Kerosene Fuel

n this work, a simple numerical model of the evaporation process of a single droplet of various fuels, e.g., n-alkanes (n-decane, n-hexane, and n-heptane) and kerosene is evaluated with various correlations at standard pressure (0.1 MPa) and various uniform temperature fields. The effect of natural, forced or combined convection is explored using an effective Reynolds number (Reeff). Studies are performed for n-alkanes and kerosene droplets and have been compared with the empirical data available in the literature for the temporal variation of droplet diameter, droplet surface temperature, and average evaporation rate constants at various temperatures under free-stream and quiescent conditions. A good match is observed for a particular property rule (Eq. 10), with different convective correlations, depending on the convective conditions present

Droplet vaporization modeling of rapeseed and sunflower methyl esters

For numerical simulations of the combustion of liquid fuels, a thoroughly validated and verified quantitative model for droplet evaporation is necessary. In this work a simple single droplet infinite conductivity model is simulated for low pressure (0.1 MPa) and various temperatures (550–1050 K) using a chosen property rule (see Eq. (7)) and five convection correlations (C1, C2, C3, C4, and C5, see (Table 1) to obtain the temporal evolution of droplet diameter squared, droplet surface temperature and average evaporation rates of vegetable oil derived biofuels – rapeseed methyl ester (RME) and sunflower methyl ester (SME) – under near-quiescent conditions. The predictions are compared with the experimental and analytical results of Morin et al. [1]. The model uses an effective Reynolds number to conflate the effects of forced and natural convection. It is observed that the predicted temporal history of droplet diameter for RME droplet matches more closely with correlation C1 for Tamb ⩽ 748 K and correlation C2 for Tamb ⩾ 803 K at various ambient temperatures (i.e., from low to high evaporation rate). The correct droplet lifetime is predicted best by C1 for all temperatures. For average evaporation rates for SME, C1 best fits the experimental data. For the average evaporation rate of RME, the present model with C1 gives a better prediction than the theoretical, and corrected theoretical results of Morin et al. [1], and is observed to match closely with their experimental results. The present results using C2 are also found close to the experimental results for RME and SME. It is observed that the oxidation of RME/SME is similar to n-decane – a pure component fuel

A numerical investigation of the Eulerian PDF transport approach for modeling of turbulent non-premixed pilot stabilized flames

Presumed shape multi-environment Eulerian PDF Transport method (MEPDF), which involves representing the joint composition PDF shape as a collection of finite number of Delta functions, has been used to model the turbulence-chemistry interactions. The governing transport equations are solved for the probability and the probability weighted mass fraction of species and enthalpy in an Eulerian frame. The radiation heat transfer is included using the non-gray modeling of the radiative properties of the medium by weighted sum of gray gases (WSGG) considering four fictitious gray gases. The absorption coefficients as well as the weight functions of the gray gases are calculated from published literature as a function of the species mass fraction and temperature. The effect of turbulence radiation interaction (TRI) is included using an empirical relations for emission enhancement. The combined tool is then used to model two pilot stabilized hydrocarbon flames (Sandia Flame D and Delft Flame III) with realistic finite rate chemistry. A parametric study of the micro-mixing constant is performed to understand its impact in flame stabilization. In case of Delft Flame III, two different pilot treatments are considered and also the impact of pilot flame power is studied with the MEPDF model. The current model results have been compared with the experimental data and also with the Lagrangian solution of the joint composition PDF transport equation. The discrepancies of the current predictions with the experimental data and other published results have been quantified and discussed