Advances in Nanoparticles, 2013, 2, 384-390
Published Online November 2013 (
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Synthesis and Characterization of Carbon Conditioned
with Iron Nanoparticles Using Pineapple-Peel
G. García-Rosales1*, L. C. Longoria-Gándara2, S. Martínez-Gallegos1, J. González-Juárez1
1Posgrade Department, Instituto Tecnologico de Toluca, Metepec, México
2Scientific Reseach and Reactor, Instituto Nacional de Investigaciones Nucleares,
Ocoyoacac, México
Email: *
Received September 3, 2013; revised October 30, 2013; accepted November 9, 2013
Copyright © 2013 G. García-Rosales et al. This is an open access article distributed under the Creative Commons Attribution Li-
cense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
This paper presents the preparation of carbon conditioned with iron nanoparticles (CI) using a pineapple peel treated
with iron salts, carboxymethylcellulose sodium and hexamine. First, the pineapple peel was analyzed by thermo gra-
vimetric analysis (TGA) to determine the optimal temperature for pyrolysis. The formation of carbon conditioned by
iron nanoparticles was studied as a function of time at 30 min, 60 min, 90 min, 120 min, 150 min and 180 min. Scan-
ning electron microscopy (SEM) was used to identify changes in the morphology of the materials. The specific area of
each material was obtained by the BET method. The elemental composition of pineapple-peel (PP), washed pineap-
ple-peel (WPP) and carbon iron (CI), was determined by neutron activation analysis (NAA). The results show that the
optimal time for obtaining spherical iron nanoparticles with a diameter between 10 nm and 30 nm is 180 min on the
carbonaceous material with a specific surface area of 167 m2/g.
Keywords: Pineapple; Carbon; Iron-Nanoparticles; Synthesis; Neutron Activation Analysis
1. Introduction
Iron nanoparticles are used in environmental applications,
such as the removal of toxic metals from polluted water
[1-3]; however, a major drawback is that their size limits
direct application because handling is difficult unless
they are recovered through an ultrafiltration system [4].
Therefore, a material that can function as a support is
recommended for using iron nanoparticles [5-8]. Carbo-
naceous materials that are obtained from organic cellu-
losic waste and then conditioned with iron nanoparticles
can be a good choice for environmental applications,
such as the removal of metals in water [9-13]. The ad-
vantage of using carbon obtained from biomass and con-
ditioned with iron nanoparticles is that synthesis of both
the carbonaceous material and the nanoparticles can be
performed simultaneously during pyrolysis, if the bio-
mass has been previously chemically conditioned. In this
work, pineapple peel conditioned with iron salts, hexa-
mine and sodium carboxymethylcellulose was used to
obtain carbonaceous material containing iron nanoparti-
cles via pyrolysis. First, the pineapple peel was analyzed
by thermo gravimetric analysis (TGA) to determine the
optimal pyrolysis temperature. Pyrolysis is performed at
different reaction times: 30 min, 60 min, 90 min, 120 min,
150 min and 180 min. To determine the effect of pyroly-
sis time on both the morphology and the size of nanopar-
ticles in the carbon matrix, characterization via scanning
electron microscopy (SEM) and calculation of the spe-
cific surface area via the BET method were performed.
Finally, the neutron activation analysis (NAA) was used
to determine the elemental composition.
2. Materials and Methods
2.1. Washing and Drying of Pineapple Peel
For this study, pineapples obtained from Mexico were
used. In the laboratory experiments, the peel was sepa-
rated from the pineapple, then ground and sieved to ob-
tain a size of 0.85 mm. The material was washed several
times with double-distilled water to remove surface im-
purities and then dried at 25˚C for 24 h. The pineapple
peels were then repeatedly washed with water at 120˚C
for 15 min to remove the brown discoloration completely,
and finally dried at 25˚C for 24 h.
*Corresponding author.
2.2. Thermogravimetric Analysis
To determine the optimal temperature for pyrolysis, a
small amount of sample was placed directly onto a plati-
num crucible, and TGA was performed using a calo-
rimetric SDT Q600 (TA Instruments-Waters) under N2 at
a heating rate of 10˚C min1 with a temperature range of
25˚C - 800˚C.
2.3. Synthesis
A mixture of 12 mL C28H30Na8O27 (2% w/w; Sigma-
Aldrich®), 18 mL Fe(NO3)3·9H2O (0.06 M; Sigma-Al-
drich®, 98%) and 6 mL (CH2)6N4 (0.5 M; Sigma-Al-
drich®, 99.9%) was combined in a reactor under Ar with
constant agitation. Once the mixture was homogenized, 3
g pineapple peel (mesh 20) was added to the mixture and
agitated in an ultrasonic bath for 45 min prior to being
placed in a fused alumina crucible, which was then sub-
sequently introduced into a quartz tube under argon
within a furnace (Lindberg®/Blue Model CC58114A-1).
To determine the effect of synthesis time on the mor-
phology of the nanoparticles, six samples were prepared
using pyrolysis times of 30 min, 60 min, 90 min, 120 min,
150 min and 180 min; the products obtained were labeled
CFe30, CFe60, CFe90, CFe120, CFe150 and CFe180,
2.4. Scanning Electron Microscopy and Specific
Surface Areas
The morphology of the material was analyzed with a
scanning electron microscope (Model JEOL® JSM-6610
LV) at 25 kV. The samples were mounted on an alumi-
num holder with aluminum conductive tape and were
then covered with a layer of gold approximately 150 Å
thick using a sputter coater (Desk II model, Denton
Vacuum). In all cases, micrographs were obtained using
a backscattered electron detector. The elemental compo-
sitions of the samples were then determined by energy
dispersive spectroscopy (EDS) using an OXFORD spec-
trometer. The diameters of the particles obtained were
measured using MeasureIt software (Olympus Soft Im-
aging Solutions). The specific surface area, pore volume
and pore diameter of the carbonaceous materials were
determined by the Brunauer-Emmett-Teller (BET) nitro-
gen adsorption method in a BELPREP-flow II surface
area analyzer (BEL JAPAN Inc.). The dried and de-
gassed samples were then analyzed by a multipoint N2
adsorption-desorption method at room temperature.
2.5. Elemental Composition
The NAA was performed using the comparator method.
Approximately 30 mg of each sample, PP (prewashed
pineapple), PPL (pineapple washed) and CFe180 (carbon
with iron), was encapsulated in polyethylene containers
for the shorter irradiation times (30 s and 5 min) and in
quartz vials for irradiation of 20 h. Lichen BCR-482 and
IAEA-Soil 7 were used as reference materials. The en-
capsulated samples were irradiated for 30 s to 5 min with
a thermal neutron flux·s of 1.3 × 1013 n/cm2 in an Irradia-
tion System tire (SINCA) in a TRIGA Mark III reactor
(ININ, Mexico) and for irradiation of 20 h in the Fixed
Irradiation System (SIFCA) with a flow of 9 × 1012
n/cm2·s. The activity of the samples was measured in a
gamma spectrometer equipped with an ORTEC® hyper-
pure Ge detector.
3. Results and Discussion
3.1. Thermogravimetric Analysis
Figure 1 shows the relative mass loss (TGA) and differ-
ential thermal analysis (DTA) curves corresponding to the
dried pineapple-peel.
The endothermic mass loss (8.3 wt%) observed for
temperatures lower than 120˚C can be attributed to water
desorption [14,15]. The second mass loss (30.56 wt%)
between 120˚C and 190˚C is associated with the decom-
position of organic substances. Beyond this temperature,
thermal degradation of the main components of the bio-
mass begins: from 190˚C - 320˚C, hemicellulose de-
grades, followed by cellulose from 320˚C - 400˚C, and
then lignin above 400˚C (59.94 wt%) [16]. In agreement
with Gutierrez et al. [17], a pineapple-peel has an average
fiber content of 67.88% (including cellulose, hemicellu-
lose, lignin and silica), which renders this waste biomass
suitable for obtaining carbonaceous material [18]. Stabi-
lization of the material was observed above 625˚C, and
the total weight loss calculated until 650˚C was 77.47
wt%. Based on this result, the selected pyrolysis tem-
perature was 650˚C to obtain carbonaceous material.
3.2. Effect of the Pyrolysis Time on Nanoparticle
Morphology and Specific Surface Area
To characterize the textural properties of the carbona-
Figure 1. Thermogravimetric and DTA curves of pineapple
peel powder.
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ceous materials obtained at 30 min, 60 min, 90 min, 120
min, 150 min and 180 min, these materials were chemi-
cally and morphologically analyzed. Figure 2(a) shows
that the material synthesized at 30 minutes does not possess
Figure 2. Micrographs, mapping and size distribution particle of iron carbon samples obtained at different synthesis times. a)
CFe30 min; b) CFe60 min; c) CFe 90 min; d) CFe 120; e) CFe 150 min; f) CFe 180 min.
a homogeneous morphology; there are rough spots. Nu-
cleation of spherical particles with an average diameter
of 114.8 nm (σ = 19.3) occurs, which is in agreement
with EDS analysis, having a composition of C(82 wt%),
O(14.22 wt%), Na(1.43 wt%), Si(0.64 wt%), K(0.29
wt%), Ca(0.76 wt%) and Fe(0.64 wt%).
In Figure 2(b), for the pyrolysis sample obtained at 60
min, there are chains of spheres with an average diameter
of 88.06 nm (σ = 12.22) forming filaments with a length
of 300 nm - 600 nm. The composition of the spheres is C
(77.63 wt%), O (17.50 wt%), Na (2.01 wt%), Al (0.45
wt%), Si ( 1.18 wt%), Ca (0.28 wt%) and Fe (0.95 wt%).
The sample obtained at 90 minutes (Figure 2(c)) forms a
defined group of particles apparently caused by segrega-
tion of the filaments previously observed at 30 min
(Figure 1(b)). The morphology of some of these particles
is not completely spherical; there are ovals 250 × 125 nm
in dimension and spherical particles with an average di-
ameter of 71.21 nm (σ = 11.93). Elemental analysis
shows a presence composition of C (80.92 wt%), O
(16.03 wt%), Na (1.83 wt%), Si (0.31 wt%), Ca (0.63
wt%) and Fe (0.38 wt%). Figure 2(d) shows the sample
obtained at 120 min in which spherical nanoparticles are
dispersed with an average diameter of 57.69 nm (σ =
9.02) and have an elemental composition of C (82.45
wt%), O (11.60 wt%), Na (1.36 wt%), Mg (0.34 wt%), Si
(1.10 wt%), K (0.05 wt%), Ca (0.76 wt%), and Fe (1.34
wt%). In the sample obtained at 150 minutes (Figure
2(e)), the nanoparticles are the best dispersed and have
an average diameter of 44.09 nm (σ = 17.09); their com-
position consists of C (75.02 wt%), O (18.48 wt%), Na
(2.26 wt%), Si (1.08 wt%), K (0.36 wt%), Ca (0.77 wt%)
and Fe (1.03 wt%). At 180 min (Figure 2(f)), there is a
reduction in particle size without noticeable changes in
the spherical shape, having an average diameter of 32.94
nm (σ = 6.75); the composition is C (75.57 wt%), O
(18.47 wt%), Na (1.81 wt%), Si (0.95 wt%), K (0.38
wt%), Ca (1.58 wt%) and Fe (1.24 wt%). The sample
obtained after 180 minutes of pyrolysis has a more defined
particle size as well as spherical morphology.
This effect can be attributed to the use of carboxy-
methyl cellulose sodium and hexamine, which favors the
formation of iron nanoparticles of uniform size at this time
scale [19,20].
To determine the specific area and pore size of the
materials, a carbon sample without iron (CB180) was
synthesized to determine the influence of the presence of
iron nanoparticles on the specific area. The results of this
experiment on the effect of iron nanoparticles are sum-
marized in Table 1. In general, the specific area in all
materia ls is more strongly affected by the pyrolysis time,
with larger values observed for the samples containing
iron compared to the CB sample.
The specific area of CFe180 is higher than that of CFe30
by 91.3 m2/g, thereby implying that the specific areas
increase with increased pyrolysis time due to the forma-
tion of iron nanoparticles in the carbonaceous material.
However, a difference of 23.1 m2/g between the spe-
cific areas of CFe180 and CB is attributed to the presence
of iron nanoparticles [21]. CFe60 and CFe120 possess
larger specific areas than CFe180, which can be attributed
to the presence of iron nanoparticles with different mor-
phologies and to changes in the porosity of the carbona-
ceous matrix that are associated with the pyrolysis process
[22]. However, the value of CFe180 is greater, which
could favor its use in environmental applications for the
removal of contaminants from water.
3.3. Chemical Composition
Table 2 lists the results from neutron activation analysis
of the PP, PPL, CB and CFe180 samples. Initially, PPL
contains these elements: Al, Br, Ce, Co, Cr, Cs, Eu, Fe,
Hf, K, La, Mg, Mn, Na, Rb, Sb, Sc and Zn. The majority
of these elements are present in the soil where a plant
grows and can accumulate in and be incorporated into
their structure during nutrient absorption, which is nec-
essary for plant growth [23].
Table 1. Specific area, volume and diameter of pore in carbonaceous materials.
Material Specific area (m2/g) Volume of pore (cm3/g) Diameter of pore (nm)
CB 98.80 0.0598 2.42
CFe30 75.70 0.0496 2.62
CFe60 284.41 0.1668 2.34
CFe90 162.36 0.0917 2.26
CFe120 182.50 0.0931 2.04
CFe150 161.03 0.0963 2.39
CFe180 167.00 0.1053 2.52
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Table 2. Elemental compositions of PP, PPL, CB y CFe.
Isotop PP [ppm] PPL [ppm] CB [ppm] CFe [ppm]
28Al 144 ± 14 60 ± 6 D 498 ± 14
82Br 17 ± 0.87 1.46 ± 0.07 4 ± 0.25 4.6 ± 0.24
141Ce 0.122 ± 0.02 ** 0.3 ± 0.0293 0.14 ± 0.02
60Co 0.29 ± 0.01 0.1612 ± 0.007 0.24 ± 0.0116 0.29 ± 0.014
51Cr 2.21 ± 0.07 0.9382 ± 0.0395 2.95 ± 0.091 2.6 ± 0.08
134Cs 0.074 ± 0.0001 ** 0.065 ± 0.0073 0.074 ± 0.006
152Eu 0.007 ± 0.0001 0.0032 ± 0 0.0083 ± 0.0014 0.0074 ± 0.001
59Fe 4020 ± 8 36.71 ± 3 4409 ± 85 5197 ± 98
181Hf 0.018 ± 0.0001 0.0098 ± 0.002 0.08 ± 0.0056 0.020 ± 0.004
42K 28342 ± 1063 362 ± 46 ** **
140La 0.159 ± 0.01 ** ** **
27Mg 460 ± 6 193 ± 24 456 ± 105 662 ± 79
56Mn 92 ± 3 60 ± 1.7 124 ± 4 152 ± 4
24Na ** ** 32947 ± 929 30499 ± 851
86Rb 2.24 ± 0.3 0.90 ± 0.1759 2 ± 0.4 3 ± 0.4
124Sb 0.783 ± 0.03 0.03 ± 0.0045 0.58 ± 0.0263 0.8424 ± 0.04
46Sc 0.010 ± 0.0001 0.005 ± 0.0004 0.014 ± 0.0007 0.0112 ± 0.0008
65Zn 132 ± 6 42 ± 2 115 ± 5 136 ± 6
**No detected.
In the PP, PPL, CB and CFe samples, the elements that
are present at low concentrations (0 - 0.08 ppm) are Eu, Sc
and Hf, where Hf is the most abundant; this result is in
accordance with Gutiérrez et al., who considered these
elements to be attached to the plant structure because they
aregenerally present in the soil. Meanwhile, Cs, La, Co
and Ce are present at concentrations between 0.050 ppm
and 0.30 ppm; Sb, Cr and Rb have concentrations of 1
ppm to 4 ppm. Br, Mn, Zn and Al are found at high con-
centrations because they are considered to be essential
components of plant tissues, especially in the CFe sample
in which the concentration of Al is nearly 500 ppm.
Mn and Zn are present because they are essential for
plant metabolism. This analysis also confirmed the pres-
ence of Mg and Fe as natural components in the pineapple
peel (Ananas comosus) because both elements are essen-
tial for photosynthesis.
Na and K are the most abundant elements; the presence
of Na in the CFe and CB samples is mainly due to the use
of sodium carboxymethyl cellulose during the chemical
conditioning of the pineapple-peel. The increase in con-
centration of the elemental compositions in PPL, CB and
CFE can be attributed to the loss of organic matter during
pyrolysis [24]. The presence of different elements in these
samples could facilitate the formation of active sites on
the material surface, thereby favoring their effectiveness
as a sorbent in the removal of metal contaminants in an
aqueous phase [25].
4. Conclusion
In this paper, the use of a pineapple peel that was chemi-
cally conditioned with iron salts, sodium carboxymethyl
cellulose and hexamine yielded a carbonaceous material
with iron nanoparticles following pyrolysis. The synthe-
sis time had a significant effect on the morphology, parti-
cle size and specific area of the carbonaceous material
was obtained. The elemental composition determined by
Neutronic Activation Analysis of CP, CPL, and CFe
showed the presence of Al, Co, Cr, Cs, Fe, Hf, K, Mg,
Mn, Na, Rb, Sc, Zn, Ce, Eu, La, Sb and Br. The method
proposed in this study provides a simple technique for
synthesizing iron nanoparticles in a carbon matrix.
5. Acknowledgements
The authors gratefully acknowledge DGEST for partial
financial support of this work and thank Jorge Perez for
his helpful assistance with electron microscopy analysis.
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[1] M. Dickinson and T. B. Scott, “The Application of Zero-
Valent Iron Nanoparticles for the Remediation of a Ura-
nium-Contaminated Waste Effluent,” Journal of Haz-
ardous Materials, Vol. 178, No. 1-3, 2010, pp. 171-179.
[2] M. Diao and M. Yao, “Use of Zero-Valent Iron Nanopar-
ticles in Inactivating Microbes,” Water Research, Vol. 43,
No. 20, 2009, pp. 5243-5251.
[3] H.-L. Lien and W. Zhang, “Nanoscale Iron Particles for
Complete Reduction of Chlorinated Ethenes,” Colloids
and Surfaces A: Physicochemical and Engineering As-
pects, Vol. 191, No 1-2, 2001, pp. 97-105.
[4] V. Zaspalis, A. Pagana and S. Sklari, “Arsenic Removal
from Contaminated Water by Iron Oxide Sorbents and
Porous Ceramic Membranes,” Desalination, Vol. 217, No.
1-3, 2007, pp. 167-180.
[5] X. Zhang, S. Lin, X.-Q. Lu and Z.-L. Chen, “Removal of
Pb(II) from Water Using Synthesized Kaolin Supported
Nanoscale Zero-Valent Iron,” Chemical Engineering Jour-
nal, Vol. 163, No. 3, 2010, pp. 243-248.
[6] C.-B. Wang and W.-X. Zhang, “Synthesizing Nanoscale
Iron Particles for Rapid and Complete Dechlorination of
TCE and PCBs,” Environmental Science and Technology,
Vol. 31, No. 7, 1997, pp. 2154-2156.
[7] H. Zhu, Y, Jia, X. Wu and H. Wang, “Removal of Arsenic
from Water by Supported Nano Zero-Valent Iron on Ac-
tivated Carbon,” Journal of Hazardous Materials, Vol.
172, No. 2-3, 2009, pp. 1591-1596.
[8] W. Wang, M. Zhou, Q. Mao, J. Yue and X. Wang,
“Novel NaY Zeolite-Supported Nanoscale Zero-Valent
Iron as an Efficient Heterogeneous Fenton Catalyst,” Ca-
talysis Communications, Vol. 11, No. 11, 2010, pp. 937-
[9] J. F. González, S. Román, J. M. Encinar and G. Martínez,
“Pyrolysis of Various Biomass Residues and Char Utili-
zation for the Production of Activated Carbons,” Journal
of Analytical and Applied Pyrolysis, Vol. 85, No. 1-2,
2009, pp. 134-141.
[10] J. Hayashi, T. Horikawa, I. Takeda, K. Muroyama and F.
N. Ani, “Preparing Activated Carbon from Various Nut-
shells by Chemical Activation with K2CO3,” Carbon, Vol.
40, No. 13, 2002, pp. 2381-2386.
[11] L. Lorenzen, J. S. J. Van Deventer and W. M. Landi,
“Factors Affecting the Mechanism of the Adsorption of
Arsenic Species on Activated Carbon,” Minerals Engi-
neering, Vol. 8, No. 4-5, 1995, pp. 557-569.
[12] Z. Liu, F.-S. Zhanga and R. Sasai, “Arsenate Removal
from Water Using Fe3O4-Loaded Activated Carbon Pre-
pared from Waste Biomass,” Chemical Engineering Jour-
nal, Vol. 160, No. 1, 2010, pp. 4-9.
[13] Z. Liu and F.-S. Zhang, “Nano-Zerovalent Iron Contained
Porous Carbons Developed from Waste Biomass for the
Adsorption and Dechlorination of PCBs,” Bioresource
Technology, Vol. 101, No. 7, 2010, pp. 2562-2564.
[14] H. P. Yang, R. Yan, H. P. Chen, D. H. Lee and C. G.
Zheng, “Characteristics of Hemicellulose, Cellulose and
Lignin Pyrolysis,” Fuel, Vol. 88, No. 12-13, 2007, pp.
[15] J. A. Conesa, A. Marcilla, J. A. Caballero and R. Font,
“Comments on the Validity and Utility of the Different
Methods for Kinetic Analysis of Thermogravimetric
Data,” Journal of Analytical and Applied Pyrolysis, Vol.
58-59, 2001, pp. 617-633.
[16] J. J. M. Órfão, F. J. A. Antunes and J. L. Figueiredo,
“Pyrolysis Kinetics of Lignocellulosic Materials: Three
Independent Reactions Model,” Fuel, Vol. 78, No. 3,
1999, pp. 349-358.
[17] F. Gutiérrez, A. Rojas Bourillón, H. Dormond, M. Poore
and W. Ching-Jones, “Características Nutricionales y
Fermentativas de Mezclas de Desechos de Piña y Aví-
colas,” Agronomía Costarricense, Vol. 27, No. 1, 2003,
pp. 79-89.
[18] P. McKendry, “Energy Production from Biomass (Part 2):
Conversion Technologies,” Bioresource Technology, Vol.
83, No. 1, 2002, pp. 47-54.
[19] F. He and D. Zhao, “Manipulating the Size and Dispersi-
bility of Zerovalent Iron Nanoparticles by Use of Car-
boxymethyl Cellulose Stabilizers,” Environmental Sci-
ence and Technology, Vol. 41, No. 17, 2007, pp. 6216-
[20] X. Shen, L. Jiang, Z. Ji, J. Wu and H. Zhou, “Stable
Aqueous Dispersions of Graphene Prepared with Hexa-
methylenetetramine as a Reductant,” Journal of Colloid
and Interface Science, Vol. 354, No. 2, 2011, pp. 493-497.
[21] X. Zhang, S. Lin, X.-Q. Lu and Z.-L. Chen, “Removal of
Pb(II) from Water Using Synthesized Kaolin Supported
Nanoscale Zero-Valent Iron,” Chemical Engineering Jour-
nal, Vol. 163, No. 3, 2010, pp. 243-248.
[22] L. B. Hoch, E. J. Mack, B. W. Hydutsky, J. M. Hershman,
J. M. Skluzacek and T. E. Mallouk, “Carbothermal Syn-
thesis of Carbon-Supported Nanoscale Zero-Valent Iron
Particles for the Remediation of Hexavalent Chromium,”
Environmental Science and Technology, Vol. 42, No. 7,
2008, pp. 2600-2605.
[23] A. Kabata-Pendias, “Trace Elements in Soils and Plants,”
Taylor and Francis Group, LLC., Boca Raton, 2011.
[24] P. T. Williams and A. R. Reed, “Pre-Formed Activated
Carbon Matting Derived from the Pyrolysis of Biomass
Open Access ANP
Open Access ANP
Natural Fibre Textile Waste,” Journal of Analytical and
Applied Pyrolysis, Vol. 70, No. 2, 2003, pp. 563-577.
[25] H. Tamura, A. Tanaka, K. Mita and R. Furuichi, “Surface
Hydroxyl Site Densities on Metal Oxides as a Measure
for the Ion-Exchange Capacity,” Journal of Colloid and
Interface Science, Vol. 209, No. 1, 1999, pp. 225-231.