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Effect of molybdenum content on
heat treatment behavior of
multi-alloyed white cast iron

รศ. ดร.ประสงค ศร�เจรญ� ชัย ภาคว�ชาวศ� วกรรมโลหการ
0-2218-6949 [email protected]

ABSTRACT

The effect of the Molybdenum (Mo) content on the heat treatment behavior of multi-alloyed white

cast iron was investigated. The cast iron with varying Mo contents from 0.12 to 7.66% under the basic alloy

composition of 5% Cr, W and V each was prepared. After annealing at 1223 K for 18 ks, the test specimens

were austenitized at 1373 K for 3.6 ks in a vacuum furnace and subsequently hardened by a jet-spray of

liquid nitrogen. The tempering was carried out at temperatures from 673 to 873 K at 50 K intervals for 12 ks.

It was found that the hardness in the as-hardened state was increased progressively with an increase in the

Mo content. The volume fraction of the retained austenite (Vγ) decreased markedly when the Mo content
was increased over 1.17%. In the tempered state, the hardness curve showed clear secondary hardening

due to the precipitation of fine secondary carbides and a reduction of the Vγ. The Vγ value in each specimen
decreased gradually as the tempering temperature was elevated, but reduced greatly when tempered at

748 to 823 K. The maximum tempered hardness (HTmax) was obtained in the specimen tempered at 798 K
where the Vγ was less than 10%. The HTmax increased first, and then subsequently decreased with an
increase in the Mo content. The highest HTmax value, 946 HV30, was obtained in the specimen with 4.98%
Mo. It was found that the 15–37%Vγ in the as-hardened state was necessary to get the hardness over 900
HV30 by tempering. The degree of secondary hardening (ΔHs) increased as the Mo content rose from 0.12

to 4.98% where the difference between the Vγ in the as-hardened state and that at HTmax (ΔVγ) was 22–23%.

FULL PAPER (LINK)

ดูเพ่มิ เตมิ ไดท ่ีวารสาร
Materials Transactions
ตพี ิมพป  2017 ฉบบั ที่ 58 หนา 655-662

https://www.jstage.jst.go.jp/article/matertrans/58/4/58_M2016396/_article

หนว ยสอ่ื สารองคก ร [email protected]

Ferromagnetism and diamagnetism
behaviors of MgO synthesized
via thermal decomposition method

ผศ. ดร.บุญรตั น โลวงศวฒั น ภาคว�ชาวศ� วกรรมโลหการ
0-2218-6939 [email protected]

ABSTRACT

MgO powders were synthesized by a thermal decomposition method
which was determined by differential scanning calorimetry coupled with ther-
mogravimetric analysis (TG/DSC). The starting material, Mg(OH)2, was calcined
at 400 °C, 450 °C and 500 °C for 1 h each to obtain the MgO
powders. Phase composition, morphology and magnetic properties at room
temperature of calcined powders were characterized using
X-ray diffraction (XRD), transmission electron microscopy (TEM),
X-ray photoelectron spectroscopy (XPS), fourier transform infrared
Spectroscopy (FTIR) and vibrating sample magnetometer (VSM), respectively.
Both Mg(OH)2 and MgO phases were found in all calcined powders. The combi-
nation of ferromagnetism and diamagnetism at room temperature of all pow-
ders were observed. It is believed to be attributed to Mg vacancies and defect in
the MgO and Mg(OH)2 structures.

FULL PAPER (LINK)

ดเู พิ่มเตมิ ไดท ี่วารสาร
Journal of Alloys and Compounds
ตีพิมพป  2017 เดอื นพฤษภาคม ฉบับท่ี 705 หนา 668-674
https://www.sciencedirect.com/science/article/pii/S0925838817306072

หนว ยสอ่ื สารองคก ร [email protected]

The behavior of gypsum-bonded
investment in the gold jewelry
casting process

อ. ดร.เชษฐา พนั ธเคร�อบตุ ร ภาคว�ชาวศ� วกรรมโลหการ

02-218-6945 Email: [email protected]

ABSTRACT

Gypsum-bonded investment, which is commonly used in gold casting,
can cause several defects such as gas porosity from the decomposition
of gypsum. Thus, the insight study in the behavior of gypsum - bonded
investment can lead to resolve the problem in casting process. It consists
of SiO2 (α-cristobalite and α-quartz) as a refractory and gypsum as a
binder. During burn out process, the dehydration of gypsum, the
inversion of cristobalite and quartz and the III–II CaSO4 transition were
determined using differential scanning calorimetry (DSC) coupled
with thermogravimetry analyzer (TGA) and in - situ X-ray diffraction
(in-situ XRD). Calcium carbonate (CaCO3) layer on the gold product
surface after casting was investigated by X-ray photoelectron
spectroscopy (XPS). It is believed to be attributed to the reaction
between CO2 from residues of carbonized wax and CaO from the de-
composition of CaSO4. This observation is may be responsible for high
roughness and low quality in the gold casting.

FULL PAPER (LINK)

ดเู พ่ิมเตมิ ไดท ่ีวารสาร
Thermochimica Acta
ตพี มิ พป 2017 เดือนพฤศจกิ ายน ฉบบั ท่ี 657 หนา 144-150
https://www.sciencedirect.com/science/article/pii/S0040603117302290

หนว ยสอ่ื สารองคก ร [email protected]



Drift-flux correlation for gas-liquid
two-phase flow in a horizontal pipe

ผศ. ดร.สมบรู ณ รัศมี ภาควช� าวศ� วกรรมนิวเคลยี ร
0-2218-6778 Email:[email protected]

ABSTRACT

A drift-flux correlation has been often used to predict void fraction of gas-liquid two-phase flow in a
horizontal channel due to its simplicity and practicality. The drift-flux correlation includes two important
drift-flux parameters, namely, the distribution parameter and void-fraction-weighted-mean drift velocity.
In this study, an extensive literature survey for horizontal two-phase flow is conducted to establish void
fraction database and to acquire existing drift-flux correlations. A total of 566 data is collected from 12
data sources and 4 flow-regime-dependent and 1 flow-regime-independent drift-flux correlations are
identified. The predictive capability of the existing drift-flux correlations is assessed using the collected
data. It is pointed out that the drift velocity determined by a regression analysis may include a significant
error due to a compensation error between distribution parameter and drift velocity. In this study, a
simple flow-regime-independent drift-flux correlation is developed. In the modeling approach, the
void-fraction-weighted mean drift velocity is approximated to be 0 m/s, whereas the distribution param-
eter is given as a simple function of the ratio of non-dimensional superficial gas velocity to non-dimen-
sional mixture volumetric flux. The newly developed correlation shows an excellent predictive capability
of void fraction for horizontal two-phase flow. Mean absolute error (or bias), standard deviation (random
error), mean relative deviation and mean absolute relative deviation of the correlation are 0.0487, 0.0985,
0.0758 and 0.206, respectively. The prediction accuracy of the correlation is similar to the correlation of
Chexal et al. (1991), which was formulated based on the drift-flux parameters by means of many cascading
constitutive relationships with numerous empirical parameters.

FULL PAPER (LINK)

ดูเพม่ิ เตมิ ไดที่วารสาร
Journal of Heat and Fluid Flow
ตีพิมพป 2018 เดือนกุมภาพนั ธ ฉบบั ท่ี 69 หนา 33-42
https://www.sciencedirect.com/science/article/pii/S0142727X17307865#!

หนว ยสอ่ื สารองคก ร [email protected]



Performance analysis of GPS Aided
geo augmented navigation (GAGAN)
over Sri Lanka

ศ. ดร.เฉลิมชนม สถิระพจน ภาคว�ชาวศ� วกรรมสำรวจ
0-2218-6651-64 ตอ 312 [email protected]

ABSTRACT

Satellite-Based Augmentation Systems (SBAS) are being developed worldwide due to
their unique advantage of wide area coverage. GPS Aided Geo Augmented Navigation
(GAGAN) is an Indian implementation of SBAS, with three (03) geo stationary satellites in
space covering a huge area even beyond Indian Territory. This study focused on analyzing
the improvement in position solution with GAGAN corrections over Sri Lanka. In order to
test its performances, several dual and single frequency GNSS receivers were used in this
experiment, one receiver was configured as SBAS receiver and other two were kept as
GPS stand-alone receivers. Observations were carried out over seven (07) known control
stations of six (6) different districts to investigate its coverage over Sri Lanka. At each of
the tested stations the GAGAN active L1 receiver has always shown a significant accuracy
improvement over L1 uncorrected observations. Further, five out of the seven (7) obser-
vation locations the calculated average 3D positional errors were lower than 1m. Almost
79% of observations (out of 24 hours of observations) have shown acceptable 3D posi-
tional accuracy, of less than 1m, for many spatial data collection applications. However,
the local DGPS correction has shown higher reliability than GAGAN corrections with
almost 85% of observations with less than 1m, 3D positional error.

FULL PAPER (LINK)

ดเู พม่ิ เตมิ ไดท ่วี ารสาร
Engineering Journal
ตีพมิ พป  2017 เดอื นกันยายน ฉบับที่ 21 หนา 305-314
http://www.engj.org/index.php/ej/article/view/1612/651

หนว ยสอ่ื สารองคก ร [email protected]

Precise Receiver Clock Offset Estimations
According to Each Global Navigation Satellite
Systems (GNSS) Timescales

ศ. ดร.เฉลมิ ชนม สถิระพจน ภาควช� าวศ� วกรรมสำรวจ
0-2218-6651-64 ตอ 312 [email protected]

ABSTRACT

Each GNSS constellation operates its own system times; namely, GPS system time
(GPST), GLONASS system time (GLONASST), BeiDou system time (BDT) and Galileo system
time (GST). They could be traced back to Coordinated Universal Time (UTC) scale and are
aligned to GPST. This paper estimates the receiver clock offsets to three timescales: GPST,
GLONASST and BDT. The two measurement scenarios use two identical multi-GNSS geo-
detic receivers connected to the same geodetic antenna through a splitter. One receiver is
driven by its internal oscillators and another receiver is connected to the external frequen-
cy oscillators, caesium frequency standard, kept as the Thailand standard time scale at the
National Institute of Metrology (Thailand) called UTC(NIMT). The three weeks data are
observed at 30 seconds sample rate. The receiver clock offsets with respected to the three
system time are estimated and analysed through the geodetic technique of static Precise
Point Positioning (PPP) using a data processing software developed by Wuhan University -
Positioning And Navigation Data Analyst (PANDA) software. The estimated receiver clock
offsets are around 32, 33 and 18 nanoseconds from GPST, GLONASST and BDT respectively.
This experiment is initially stated that each timescale is inter-operated with GPST and
further measurements on receiver internal delay has to be determined for clock compari-
sons especially the high accuracy clock at timing laboratories.

FULL PAPER (LINK)

ดูเพมิ่ เติมไดทีว่ ารสาร
Artificial Satellites
ตพี ิมพป 2017 เดือนมกราคม ฉบับที่ 53 หนา 99-108
https://content.sciendo.com/view/journals/arsa/52/4/article-p99.xml

หนว ยสอ่ื สารองคก ร [email protected]

Quantifying deformation
in North Borneo with GPS

ศ. ดร.เฉลิมชนม สถิระพจน ภาควช� าวศ� วกรรมสำรวจ
0-2218-6651-64 ตอ 312 [email protected]

ABSTRACT

The existence of intra-plate deformation of the Sundaland platelet along its eastern edge in North Borneo,
South-East Asia, makes it an interesting area that still is relatively understudied. In addition, the motion of the
coastal area of North-West Borneo is directed toward a frontal fold-and-thrust belt and has been fueling a long
debate on the possible geophysical sources behind it. At present this fold-and-thrust belt is not
generating significant seismic activity and may also not be entirely active due to a decreasing shelfal
extension from south to north. Two sets of Global Positioning System (GPS) data have been used in this study;
the first covering a time period from 1999 until 2004 (ending just before the Giant Sumatra–Andaman
earthquake) to determine the continuous Sundaland tectonic plate motion, and the second from 2009 until
2011 to investigate the current deformations of North Borneo. Both absolute and relative positioning
methods were carried out to investigate horizontal and vertical displacements. Analysis of the GPS results
indicates a clear trend of extension along coastal regions of Sarawak and Brunei in North Borneo. On the
contrary strain rate tensors in Sabah reveal that only insignificant and inconsistent extension and compression
occurs throughout North-West Borneo. Moreover, station velocities and rotation rate tensors on the northern
part of North Borneo suggest a clockwise (micro-block) rotation. The first analysis of vertical displacements
recorded by GPS in North-West Borneo points to low subsidence rates along the western coastal regions of
Sabah and inconsistent trends between the Crocker and Trusmadi mountain ranges. These results have not
been able to either confirm or reject the hypothesis that gravity sliding is the main driving force behind the
local motions in North Borneo. The ongoing Sundaland–Philippine Sea plate convergence may also still play
an active role in the present-day deformation (crustal shortening) in North Borneo and the possible clockwise
rotation of the northern part of North Borneo as a micro-block. However, more observations need to be
collected to determine if the northern part of North Borneo indeed is (slowly) moving independently.

FULL PAPER (LINK)

ดูเพม่ิ เตมิ ไดท ่วี ารสาร
Journal of Geodesy
ตีพมิ พป  2017 เดอื นตุลาคม ฉบบั ท่ี 91 หนา 1241-1259
https://link.springer.com/article/10.1007%2Fs00190-017-1024-z

หนว ยสอ่ื สารองคก ร [email protected]

Support spinor machine

ผศ. ดร.สรรเพชญ ช้อื นธิ ิไพศาล ภาควช� าวศ� วกรรมสำรวจ
0-2218-6651- 64 ตอ 316 [email protected]

ABSTRACT

We generalize a support vector machine to a support spinor machine by
using the mathematical structure of wedge product over vector machine in
order to extend field from vector field to spinor field. The separated
hyperplane is extended to Kolmogorov space in time series data which allow
us to extend a structure of support vector machine to a support tensor
machine and a support tensor machine moduli space. Our performance test
on support spinor machine is done over one class classification of end point
in physiology state of time series data after empirical mode analysis and
compared with support vector machine test. We implement algorithm of
support spinor machine by using Holo-Hilbert amplitude modulation for
fully nonlinear and nonstationary time series data analysis.

FULL PAPER (LINK)

ดูเพมิ่ เติมไดท ีว่ ารสาร
Digital Signal Processing
ตีพมิ พป  2017 เดอื นพฤศจิกายน ฉบบั ท่ี 70 หนา 59-72

https://www.sciencedirect.com/science/article/pii/S1051200417301732

หนว ยสอ่ื สารองคก ร [email protected]



Hydrological assessment using stable iso-
tope fingerprinting technique in the Upper
Chao Phraya river basin

ผศ. ดร.อักษรา พฤทธิว�ทยา ภาคว�ชาวศ� วกรรมแหลงน้ำ
0-2218-6719 [email protected]

ABSTRACT

This study is focusing to assess the spatial and temporal distribution of rainfall using water stable isotope
technique as well as the surface water-groundwater interactions for the aquifer systems in the Upper Chao
Phraya river basin systems. Local precipitation, surface water, and groundwater along the main river courses
and their tributaries are directly samples. Massive precipitation isotopic composition database from existing
IAEA monitoring network (GNIB) along with local Bangkok precipitation isotopic signature are compared with
precipitation from Chiang Mai province to better identify the rainfall isotopic compositions. In addition to the
isotopic differentiation of precipitation in the area, its impacts on isotopic characteristics of surface water and
groundwater are additionally explored. LMWLs (Local Meteoric Water Line) for local rainfall in Bangkok and
Chiang Mai are generated with some seasonal variation due to rain out effect. Surface water is influenced by
evaporation at some degree, revealing that rainfall may not be the primary source of surface water. Yom river's
isotope values are far more D and 180-enriched compared to Ping's and Nan's, suggesting the mixing of
groundwater with river water and/or the source of surface water may come from dry-period precipitation.
Stable oxygen and hydrogen isotopes in groundwater fall on an evaporation line, and are thus indicative of
the effects of high evaporation rates through the top surficial material. The isotopic similarity with the more
depleted 6D and 5180 of groundwater samples suggests the potential mixing of groundwater with river water
by different mixing processes (54% from river water and 46% from rainfall). The results show correlations in the
isotope signature of shallow (< 50 m deep) and deeper aquifer (> 50 m deep) which may be associated with
hydraulic connection and/or similar hydrogeological conditions, d-excess stable isotope analyses are benefi-
cial to identify the relative contributions of the wet and dry seasonal sources to the groundwater recharge. The
results indicate that groundwater sources are composed of - 71.4% wet seasonal sources and -28.6% dry
seasonal sources.

FULL PAPER (LINK)

ดูเพิ่มเติมไดท วี่ ารสาร
Lowland Technology International
ตีพมิ พป 2017 เดือนมิถนุ ายน ฉบับที่ 19 หนา 27-40
https://www.researchgate.net/scientific-contributions/
2106630673_Aksara_Putthividhya

หนว ยสอ่ื สารองคก ร [email protected]

Trichloroethylene-alcohol-water solubility
characteristics with implications for parti-
tioning tracer tests at DNAPL-contaminated
sites

ผศ. ดร.อกั ษรา พฤทธวิ ท� ยา ภาคว�ชาว�ศวกรรมแหลง น้ำ
0-2218-6719 [email protected]

ABSTRACT

Dense nonaqueous phase liquids (DNAPLs) widely occurred at numerous subsurface sites can
act as long-term sources of both vapor-phase and groundwater contamination. Successful remedi-
ation and effective risk assessment of DNAPL-contaminated sites is limited by current source zone
characterization techniques and DNAPL unique behavior. A relatively new method of DNAPL-con-
taminated site characterization involved the use of partitioning tracers to provide estimates of the
known amount of DNAPL. A new practical continuous flow system was developed in this work to
explore the DNAPL's partitioning tracer-water solubility characteristics under pure phase and
selected cosolvents conditions which can be crucial for estimate retardation factors of various
tracers with implications for partitioning tracer tests at DNAPL-contaminated sites. Trichloroethyl-
ene (TCE) was selected as a representative of DNAPL due to its unique properties and solvent
effects. Bromide was employed as a non-partitioning tracer, while three alcohols (i.e., iso-propanol,
methanol, and ethanol) effluents were determined as a function of time under pure solvent and
30% cosolvent additions. The three alcohols appeared to have been used successfully as a parti-
tioning tracers for detection of potential DNAPL saturation. Moment analysis of breakthrough
curves allowed TCE and alcohol mass recovery and retardation factor calculation, and therefore
could further estimate apparent DNAPL saturation. Assuming that partitioning to TCE-DNAPL is the
only mechanism for retention of alcohols in the system, flow rate and various alcohol fraction addi-
tions seemed to have no major influence on retardation factor estimation of partitioning tracers in
the system.

FULL PAPER (LINK)

ดูเพ่มิ เตมิ ไดที่วารสาร
Lowland Technology International
ตพี มิ พป 2017 เดือนมีนาคม ฉบบั ที่ 18 หนา 249-256

หนว ยสอ่ื สารองคก ร [email protected]



In-vehicle carbon dioxide
concentration in commuting cars
in Bangkok, Thailand

I.P.D. De Silva International School of Engineering

0-2218-6422 [email protected]

ABSTRACT

It is known that in-vehicle carbon dioxide (CO ) concentration tends to increase
due to occupant exhalation when the HVAC (heating, ventilation, and air
conditioning) air is in recirculation mode. Field experiments were conducted
to measure CO concentration during typical commute in Bangkok, Thailand.
The measured concentrations agreed with the concentration predicted using
first-order mass balance equation, in both recirculating and outside air modes. The
long-term transient decay of the concentration when the vehicle was parked and
the HVAC system was turned off was also studied. This decay was found to follow
Fickian diffusion process. The paper also provides useful operational details of the
automotive HVAC system and fresh air ventilation exchange between cabininterior
and exterior.

Implications: Drivers in tropical Asian countries typically use HVAC recirculation
mode in their automobiles. This behavior leads to excessive buildup of cabin CO
concentration levels. The paper describes the CO buildup in a typical commute in
Bangkok,Thailand. Auto manufacturers can potentially take measures to alleviate
such high concentration levels. The paper also discusses the diffusion of CO through
the vehicle envelope, an area that has never been investigated before.

FULL PAPER (LINK)

ดูเพ่ิมเติมไดท ี่วารสาร
Journal of the Air and Waste Management Association
ตพี มิ พป 2017 เดอื นเมษายน ฉบับที่ 67 หนา 623-633

https://www.tandfonline.com/doi/full/10.1080/10962247.2016.1268983

หนว ยสอ่ื สารองคก ร [email protected]