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Combustion characteristics of candles made from hydrogenated soybean oil


Abstract and Figures

Hydrogenated soybean oil, referred to as soywax by candle makers, is a renewable and biodegradable alternative to paraffin wax in candle manufacturing. Soywax was investigated for its tendency to produce soot as well as potentially harmful organic volatiles (acrolein, formaldehyde, and acetaldehyde) during combustion. Beeswax and paraffin candles were used as references. A considerable amount of soot was produced from the combustion of paraffin candles, but little or none was observed from soywax candles. Compared to paraffin candles, soywax candles burned at a significantly slower rate and required less air. Small amounts of formaldehyde were detected and quantified in the fumes of burning paraffin candles. However, formaldehyde, peaks found in the chromatograms of soy- and beeswax candles were similar to or slightly higher than that of the blank. Since soywax candles exhibited burning properties similar to those of beeswax candles, soywax shows promise in candle applications.
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ABSTRACT: Hydrogenated soybean oil, referred to as soywax
by candle makers, is a renewable and biodegradable alterna-
tive to paraffin wax in candle manufacturing. Soywax was in-
vestigated for its tendency to produce soot as well as potentially
harmful organic volatiles (acrolein, formaldehyde, and acet-
aldehyde) during combustion. Beeswax and paraffin candles
were used as references. A considerable amount of soot was
produced from the combustion of paraffin candles, but little or
none was observed from soywax candles. Compared to paraffin
candles, soywax candles burned at a significantly slower rate
and required less air. Small amounts of formaldehyde were de-
tected and quantified in the fumes of burning paraffin candles.
However, formaldehyde peaks found in the chromatograms of
soy- and beeswax candles were similar to or slightly higher than
that of the blank. Since soywax candles exhibited burning prop-
erties similar to those of beeswax candles, soywax shows
promise in candle applications.
Paper no. J10259 in JAOCS 79, 803–808 (August 2002).
KEY WORDS: Candle, combustion, hydrogenated oil, organic
volatiles, soot, soybean oil, soywax.
For years, petroleum-based paraffin wax has been used as the
main component of candles. Volatile organic compounds and
small particles, commonly referred to as soot, are either di-
rectly emitted from the source material during combustion or
produced as a result of incomplete combustion of paraffin
wax (1,2). The soiling of interior surfaces of buildings due to
soot deposition was reported by Fine et al. (2). The binding
of soot to delicate materials, such as fine art, is a major con-
cern since it darkens surfaces of valuable artifacts such as
paintings and sculptures.
Soywax is a potential paraffin substitute that is biodegrad-
able, renewable, and environmentally friendly. However, its
burning characteristics are not well known. Lau et al. (1) re-
ported that 27 ng/m3acrolein was produced from the combus-
tion of 540 g stearin (a glycerol-based wax) for 3 h in a 40-m3
room. Soywax is also a glycerol-based material. Acrolein is be-
lieved to be toxic to humans and animals (3), and at 0.13 mg/m3
level, it can irritate the eyes upon exposure for 5 min. At 0.7
mg/m3, it can affect the respiratory tract. The objectives of this
work were to investigate the combustion properties of soywax
and compare them with those of paraffin and beeswax candles.
Materials. Naphthalene (laboratory grade, internal standard)
and formaldehyde solution (37%, external standard) were pur-
chased from Fisher Scientific (Fair Lawn, NJ). Acrolein (90%)
and acetaldehyde used as external standards were obtained from
Eastman Kodak Co. (Rochester, NY). 2,4,6-Trichlorophenylhy-
drazine (TCPH) (99%) was from Sigma-Aldrich Inc. (Milwau-
kee, WI), and carbon disulfide (CS2) was from Matheson Cole-
man & Bell (East Rutherford, NJ). Soft paraffin with a broad
melting range (25–80°C) and hard paraffin with two melting
peaks at 32 (minor) and 49°C (major) were obtained from
Dussek Campbell (Skokie, IL). Soywax (14.5% palmitic acid,
34.1% stearic acid, and 51.4% oleic acid, calculated iodine
value: 46) was purchased from Cargill Co. (Minneapolis, MN),
and beeswax from Strahl & Pitsch, Inc. (West Babylon, NY).
Air (medical grade, USP) used for in-chamber combustion of
waxes was obtained from Praxair Inc. (Danbury, CT).
Candle preparation. Approximately 200 g of wax was used
to prepare each candle. Each one (soywax, beeswax, or paraf-
fin) was melted and poured into a glass container (7.0 cm in di-
ameter) with a wick (made of a cotton strip with a metal disk
connected to one end) held in the center. To avoid cracking,
chipping, and/or deforming of the candles during cooldown,
wax was poured in several steps, allowing the waxes to solidify
between steps. Soywax and beeswax were used without any ad-
ditional manipulation, but a 50:50 ratio of soft and hard paraf-
fins (an appropriate ratio for proper melting; personal commu-
nication with industrial partner) was used for paraffin candles.
Melting and solidification behaviors. A differential scan-
ning calorimeter (DSC) model DSC 6200 (Seiko Instruments
Inc., Chiba, Japan) equipped with a cooling controller using
liquid nitrogen and an Exstar 6000 communication device
(Seiko Instruments Inc.) was used to evaluate the melting and
solidification behaviors of the waxes. AOCS recommended
practice Cj 1-94 (4) with modification was used to program the
DSC system. An initial hold for 2 min at 30°C followed by
ramping at 30°C/min to 80°C and holding for 10 min was ap-
plied. Then, a cooling step at 10°C/min to 40°C and 1-min
hold followed by a heating step to 80°C at 10°C/min were used.
Soot determination. For the purpose of collecting soot, can-
dles were placed on a loop standing at a height of 49.5 cm
above the benchtop. Initially, a funnel (15.0 cm in diameter)
that was equipped with a membrane filter and connected to a
vacuum pump was positioned upside-down (Fig. 1A) away
Copyright © 2002 by AOCS Press 803 JAOCS, Vol. 79, no. 8 (2002)
*To whom correspondence should be addressed at 2312 Food Sciences
Bldg., Dept. of Food Science and Human Nutrition, Iowa State University,
Ames, IA 50011. E-mail:
Combustion Characteristics of Candles
Made from Hydrogenated Soybean Oil
Karamatollah Rezaei, Tong Wang*, and Lawrence A. Johnson
Department of Food Science and Human Nutrition, and the Center for Crops Utilization Research,
Iowa State University, Ames, Iowa 50011
from the candle. To collect soot, the funnel was moved next to
the burning candle so that the lip of the funnel was 29 mm
below the edge of the candle container. Membrane filters with
5-µm pore size (SKC Inc., Eighty Four, PA) were used to col-
lect the soot. Since flame disturbance can happen at typical
room conditions, soot collection was performed under both dis-
turbed and undisturbed burning conditions. Disturbance was
defined as the small turbulence occurring on the flame due to
air draft, which was implemented by using the lowest speed of
a model 3733 Lasco fan (Lasco Products, Inc., West Chester,
PA). The fan was located 112 cm away from the candle stand.
Between two successive collections, the candle was allowed to
continue burning but the fan was turned off. Normal room con-
ditions were considered as nondisturbed or undisturbed condi-
tions. Air velocity at the tip of the candle flame during the dis-
turbed condition was 0.71–0.77 m/s as measured by a model
8455-12 air-velocity transducer (TSI, Inc., St. Paul, MN).
A Hunter colorimeter (Hunter Associates Laboratory, Inc.,
Reston, VA) with a 1-in. (2.54 cm) aperture was used to measure
the darkness of the membrane filters. The range of L value of the
soot-coated filter is 0 to 100. The instrument was standardized
by using a black tile for 0 and a white tile for 100 values.
Burn rate. To measure the candle burn rate under normal
room conditions, three candles of each type were placed alter-
nately on the benchtop (20 cm apart) and allowed to burn for
380 min. Overall burn rates were obtained by dividing the total
weight loss during candle combustion by the total burn time. A
second set of candles was used to measure dynamic burn rates
wherein burn rates were measured at different intervals through-
out the 5-h burning period. Pool diameters and flame sizes were
measured several times during the combustion periods.
Collection and analysis of acrolein, formaldehyde, and
acetaldehyde. To collect volatiles, burning was performed in a
chamber (Fig. 1B) with an air flow rate of 3.5 L/min, below
which paraffin flame could not remain lit and above which the
TCPH solution, used to collect aldehydes, was bubbled away.
The fumes were allowed to pass through three consecutive im-
pingers containing 30-, 10-, and 10-mL TCPH solutions (1.0
M phosphoric acid saturated with TCPH), respectively. TCPH
precipitates aldehyde and ketone compounds as hydrazones
(5). Collection was continued for 8 h, after which the TCPH
solutions along with the precipitates from the three impingers
were transferred to a separatory funnel. The precipitates re-
maining on the surfaces of the impingers were washed off
(using 18–20 mL CS2as solvent) and added to the separatory
funnel, where all of the hydrazone products were quantita-
tively extracted into the CS2phase, with vigorous shaking, and
separated from the aqueous TCPH solution. As much as 97%
of the total hydrazones is recovered with a one-step
solvent–solvent extraction of carbonyl compounds as 2,4-dini-
trophenylhydrazones into CS2(6). Therefore, a similar extrac-
tion level was assumed when using TCPH in this study, and
only a single extraction into CS2was performed. Also, a blank
extraction was performed using the same volumetric ratio of
TCPH solution to CS2solvent as was used for the sample ex-
traction (i.e., 50:18, respectively). All extracts in the CS2
phase were stored under refrigeration until analysis.
A Hewlett-Packard series II model 5890 gas chromato-
graph equipped with an SPB-5 fused-silica column (30 m ×
0.25 mm ×0.25 µm; Supelco, Bellefonte, PA) was used to an-
alyze the CS2extracts. Both the injection port and detector
(FID) were set at 250°C, and the oven temperature was pro-
grammed as follows: 5 min holding at 50°C, 10°C/min ramp-
ing to 230°C, and 22 min of final holding at 230°C.
Naphthalene, which had a retention time of 14.20 min, was
used as an internal standard to normalize the peaks. A primary
solution of internal standard was made by dissolving 30.0 mg
naphthalene in 3.00 mL CS2. Then, 200 µL of this solution
was mixed with 1.00 mL of sample or blank solution, and 2–3
µL of the final solution was injected for GC analysis.
Formaldehyde, acetaldehyde, and acrolein were used as
external standards for quantification purposes; these gave
peaks at 20.13 (singlet), 21.17, and 21.70 (doublet) and 22.70
min (singlet), respectively. The doublet peaks in the case of
acetaldehyde hydrazone were due to the production of syn-
and anti-isomers specifically in CS2as solvent (6). Detection
limits obtained in this study were 1.24, 0.96, and 0.76 ng for
formaldehyde, acetaldehyde, and acrolein, respectively.
Soot production. Preliminary experiments indicated a wide
variation in the level of soot production when burning paraffin
candles, in contrast to soywax and beeswax candles. There-
fore, 10 paraffin candles were allowed to burn on a benchtop.
A wide range of smoking behavior was observed in the early
stages of burning. After about 1 h, all paraffin candles pro-
duced smoke with any air movement. Similar observations of
10 soywax candles did not detect any visible smoke.
Two consecutive 2-min collections (3 min apart) of soot
were obtained from 7 of the 10 paraffin candles above, and
JAOCS, Vol. 79, no. 8 (2002)
FIG. 1. Schematic of the apparatus used for the collection of soot (A)
and aldehydes (B). TCPH: trichlorophenylhydrazine solution.
variations among all observations (i.e., 7 candles ×2 observa-
tions) were analyzed. There was considerable variation in the
amount of soot produced among the seven candles (L values =
65 ± 34). This high variation in soot production was associ-
ated with the nonuniform structure of starting materials (i.e.,
the soft and hard paraffin waxes) as well as possible variations
in the crystallization during the solidification of different can-
dle batches. For soywax and beeswax candles, the consecutive
10-min collections indicated that the total soot produced over
each collection period was negligible (hardly visible), for
which colorimetric L-values of 90 or better were obtained.
For paraffin, seven separate collections (2 min per collec-
tion over 62 min of burning) were performed under disturbed
conditions from two of the soot-producing candles identified
above, for which a mean colorimetric L-value as low as 18.7
was obtained. The average L-value was 32.4 ± 14.4 (mean ±
SD). This L-value was far below those obtained for soywax
and beeswax candles under similar conditions (95.0 ± 0.4 and
94.4 ± 2.3, respectively). In a separate experiment, one can-
dle from each type was selected and soot collection from the
disturbed conditions was compared with that of nondisturbed
conditions (Fig. 2). Average colorimetric L-values of 11.6 ±
0.8, 95.0 ± 0.9, and 86.7 ± 0.1 were obtained for two succes-
sive collections of disturbed paraffin (2-min collections), soy-
wax (10-min collections), and beeswax (10-min collections)
candles, respectively (Fig. 2). The 10-min collections for soy-
and beeswax candles were due to the fact that no soot was col-
lected within the 2-min periods applied to these types of can-
dles. For the 2-min soot collections from nondisturbed paraf-
fin candles, an average L-value of 83.6 ± 1.1 was obtained,
indicating a major effect from the disturbance in airflow. For
the 10-min collections from nondisturbed soywax and
beeswax candles, average L-values of 95.8 ± 0.0 and 95.7 ±
0.7, respectively, were obtained. During candle combustion
under typical conditions in many places, flame disturbance
by walking individuals is inevitable, and therefore paraffin
candles will produce soot.
The results from the experiments above are for unscented
paraffin candles. A higher amount of soot was reported by
Krause (7) when scented paraffin candles were burned. Like-
wise, limited quantities of soot can possibly be produced with
scented soywax candles depending on source and quantity of
the materials added for such purposes.
Wax consumption rate. For in-chamber burning of candles
(when collecting volatiles) at a 3.5 L/min air flow, burning
rates of 3.21 ± 0.37 and 4.26 ± 0.24 g/h were obtained for soy-
wax and paraffin candles, respectively. The air demand for
burning paraffin candles under controlled air flow was much
higher than that of soywax candles. Paraffin candles were ex-
tinguished if the air flow fell below 3.5 L/min.
Wax consumption rate was also determined when candles
were burned outside the chamber at ambient conditions. Six
soywax, three beeswax, and three paraffin candles were
burned simultaneously for 380 min, and burning rate and pool
diameter from each candle were measured (Table 1). Three of
the soywax candles were trimmed as necessary. Untrimmed
soywax candles burned at somewhat lower rates than paraffin
candles (4.50 ± 0.22 vs. 5.08 ± 0.18 g/h), whereas the
trimmed soywax candles had much lower burn rates (3.89 ±
0.28 g/h). This correlated well with the flame size (Fig. 3) of
soywax candles, which was smaller than that of paraffin can-
dles. Reduced wax consumption rate extends the burning time
considerably for a given candle size. A smaller flame also can
be associated with lower heat production suggesting that for
some indoor applications where heat of combustion is an
issue soywax candles have advantages. Under ambient condi-
tions these observed burning rates were higher than those for
candles burned in a chamber under controlled air flow.
The differences in the chemical compositions of soywax and
paraffin contribute to their different combustion behaviors.
Whereas soywax is a TAG, paraffin is a petroleum-based
JAOCS, Vol. 79, no. 8 (2002)
FIG. 2. Top: Colorimetric data as indicators of soot production for dif-
ferent types of candles under different air movement conditions. Results
for paraffin are for 2-min and those for soywax and beeswax are for 10-
min collections. Bottom: Typical images from the soot collected during
the disturbed combustion of the waxes: (A) paraffin (2 min), (B) soywax
(10 min), and (C) beeswax (10 min) candles. The longer times for soy-
wax and beeswax collections were due to the lack of any soot at 2-min
Combustion Properties of Three Different Types of Candles
over a 380-min Burning Period
Burning rateaPool diametera
Candle type (g/h) (cm)
Soywax (trimmed) 3.89 ± 0.28 5.4 ± 0.2
Soywax (untrimmed) 4.50 ± 0.22 6.5 ± 0.4
Beeswax 3.28 ± 0.25 3.3 ± 0.2
Paraffin 5.08 ± 0.18 4.9 ± 0.5
aMean ± SD (n= 3).
mixture of different organic compounds, 78% (w/w) of which
are GC-extractable [i.e., the fraction of the derivatized sample
that is extractable and elutable from the GTC column (2)] con-
sisting of 93% (w/w) alkanes, 6% (w/w) alkanoic acids, and 1%
(w/w) cyclohexylalkanes (2). Compared to paraffin, soywax
contains larger molecules with lower volatility and less mobil-
ity through the wax. This results in reduced flow of the melted
wax through the wick and therefore a lower consumption rate.
The burning rate of beeswax candles is also shown in
Table 1. Among the different candles studied, beeswax can-
dles burned at the lowest rate. Fine et al. (2) reported that 76%
of the total unburned beeswax was GC-extractable organic
compounds consisting of 67% (w/w) long-chain wax esters,
14% (w/w) alkanes, 15% (w/w) alkanoic acids, and 1% (w/w)
Burning soywax candles resulted in a flower- or mush-
room-like formation around the flame (Fig. 3A) as a result of
wick deformation. Such formations, which were not observed
with paraffin candles, could lead to a larger combustion area
and thus higher wax consumption. Therefore, trimming was
added to our protocol for evaluating the burning of soywax
candles. For trimmed candles, the flower-like structures were
broken or cut during the combustion period (380 min) every
45–60 min. The trimmed candles burned at a considerably
lower rate than those not trimmed (Table 1). The reduced sur-
face areas of the wicks with the trimmed candles resulted in
smaller flames and therefore lower consumption rates. In
reality, consumers do not need to perform a continuous trim-
ming for cost concerns. However, to avoid potential fire haz-
ards and to reduce soot production, manufacturers recom-
mend trimming their candle products.
Burning rates under disturbed and nondisturbed conditions
were also examined. The overall burning rate of soywax can-
dles under disturbed conditions for 2 h was 2.62 g/h. This was
considerably lower than the burning rate obtained for soywax
candles burning in normal room conditions (4.50 g/h). Simi-
larly, paraffin candles under disturbed conditions burned at
considerably lower rates than those burned under normal room
conditions (3.85 vs. 5.08 g/h, respectively). For beeswax can-
dles, there was no detectable difference between the burning
rates of the candles burned under disturbed conditions and
those burned under normal room conditions. However, slight
changes in the burn rate were observed after the candles had
burned under normal room conditions for a longer time.
Size of liquid wax (burning) pool. The diameter of the pool
created by each type of candle was measured over the burning
period of 380 min (Table 1). Soywax candles created wider
liquid pools inside the walls of their glass containers than did
paraffin candles (Figs. 3A and 3B, respectively). The liquid
pools of beeswax candles were the smallest (Fig. 3C). Several
parameters can influence the size of the molten pool. The melt-
ing and solidification profile of the waxes as obtained by a
DSC thermograph (Figs. 3D, 3E, and 3F) plays a major role in
determining the pool size. Melting onset and peak tempera-
tures for soywax were lower than those of paraffin and
beeswax, resulting in a more liquid wax during candle com-
bustion. Another parameter in determining the pool diameter
is the wick diameter. Paraffin and soywax candles with thicker
wicks created larger pools and burned at higher rates. In con-
tainer candles, the larger pool size may be desirable to clean
the container walls as burning progresses, but too much liquid
can drown the wick and extinguish the flame.
Dynamic combustion. The three types of candles were
burned for 5 h in duplicate and the changes in weight were
recorded intermittently (Fig. 4A). Paraffin candles had the
highest combustion rates (Fig. 4B), which increased with time.
JAOCS, Vol. 79, no. 8 (2002)
FIG. 3. Typical differences in liquid wax pool size and flame size among the three types of candles: (A) soywax, (B) paraffin, (C) beeswax. D, E,
and F are the DSC thermograms of these waxes, respectively.
This was consistent with the higher soot production as burning
continued. The combustion rates of soywax candles decreased
within the first ~60 min but then slowly increased as burning
continued. The decrease in combustion rate conformed to the
decrease in soot production. Little or no changes were observed
in the combustion rates of beeswax candles during the 5-h com-
bustion period. The combustion rate of each candle type was
consistent with the results from similar runs performed earlier.
The size of the liquid pool around the flame during the 5-h
combustion period changed at a greater rate during the early
stage of burning (0–40 min, Fig. 4C). The largest mean pool
size was observed in soywax candles. The mean pool size of
beeswax candles was initially similar to that of paraffin can-
dles, but, as burning continued, paraffin preceded that of
beeswax (Fig. 4C). Such behavior was consistent with the
DSC melting and solidification behaviors discussed earlier.
The beeswax candles exhibited the most uniform flame
shape, which was relatively small in height and width. After
2 h of burning, flame widths were 4.0, 5.0, and 6.0 mm for
beeswax, soywax, and paraffin candles, respectively. The
flame widths shifted to 6.0, 7.0, and 7.0 mm, respectively,
after another hour of burning, when flame heights of 1.3–1.8,
2.0–2.6, and 3.2 cm were observed for beeswax, soywax, and
paraffin candles, respectively. The flame shapes of the three
different types of candles were quite different with paraffin
candles being the largest and beeswax candles being the
smallest. Untrimmed soywax candles were intermediate with
a bulky flower- or mushroom-like formation in the center of
the flame leading to uneven flames.
Characterization of combustion compounds. A typical chro-
matogram of TCPH-captured combustion products is shown
JAOCS, Vol. 79, no. 8 (2002)
FIG. 4. (A) Profile of wax consumption in paraffin, soywax, and
beeswax candles over time. (B) Dynamic combustion rate of paraffin,
soywax, and beeswax candles. (C) Changes in the diameter of the liq-
uid pool in the three different types of candles.
FIG. 5. Typical chromatogram for the trichlorophenylhydrazones of the fumes obtained from
burning paraffin candles.
for paraffin candles in Figure 5. For soywax and beeswax can-
dles, formaldehyde was detected at levels similar to or slightly
higher than that of the blank, but its presence could not be con-
fidently associated with the combustion of these waxes. A
formaldehyde peak was obvious for paraffin candles, with an
average of 1.7 mg formaldehyde per g combusted paraffin.
Based on the minimum formaldehyde recovery of 54% in the
system, as measured by a simulated run for a standard, a maxi-
mum of 3.2 mg formaldehyde is expected to be released for
each gram paraffin consumed. No acrolein was detected in the
combustion products of soywax, beeswax, or paraffin candles
over a 5–8 h period. Lau et al. (1) reported that combustion of
paraffin candles in a nondisturbed manner produced no volatile
organic compounds that were of concern to human health.
Little information is available about health issues that may
arise from the organic compounds emitted from paraffin can-
dles. Lau et al. (1) quantified some of the materials collected
and found that the levels emitted into a closed environment
were far below their tolerance levels. Fine et al. (2) reported
that many organic compounds were emitted during the com-
bustion of paraffin candles. Their experimental procedure was
not designed to collect lower-M.W. volatile organics, but
many other compounds, such as alkanes and cycloalkanes,
alkanoic acids, alkenes, and polycyclic aromatics, were
found. Polycyclic aromatics are a health concern (8) and
should not be present in a fully refined vegetable oil.
Gratitude is expressed to the Iowa Soybean Promotion Board for fi-
nancial support and to CandleWorks (Cedar Rapids, IA) for provid-
ing candle materials. Journal Paper No. J-19568 of the Iowa Agri-
culture and Home Economics Experiment Station, Ames, Iowa. Pro-
ject No. 0178, and supported by Hatch Act and State of Iowa funds
and a grant provided by the Iowa Soybean Promotion Board.
1. Lau, C., H. Fiedler, O. Hutzinger, K.H. Schwind, and J. Hossein-
pour, Levels of Selected Organic Compounds in Materials for
Candle Production and Human Exposure to Candle Emissions,
Chemosphere 34:1623–1630 (1997).
2. Fine, P.M., G.R. Cass, and B.R.T. Simoneit, Characterization of
Fine Particle Emissions from Burning Church Candles, Environ.
Sci. Technol. 33:2352–2362 (1999).
3. Vermeire, T., Acrolein, in Environmental Health Criteria 127,
World Health Organization, Geneva, 1992, pp. 11–14.
4. Official Methods and Recommended Practices of the American
Oil ChemistsSociety, 4th edn., AOCS Press, Champaign, 1996.
5. Johnson, D.C., and E.G. Hammond, A Sensitive Method for the
Determination of Carbonyl Compounds, J. Am. Oil Chem. Soc.
48:653–656 (1971).
6. Smith, R.A., and I. Drummond, Trace Determination of Carbonyl
Compounds in Air by Gas Chromatography of Their 2,4-Dinitro-
phenylhydrazones, Analyst 104:875–877 (1979).
7. Krause, J.D., Characterization of Scented Candle Emissions and
Associated Public Health Risks, Ph.D. Dissertation, University
of South Florida, 1999.
8. Spaeth, K.R., Don’t Hold Your Breath: Personal Exposures to
Volatile Organic Compounds and Other Toxins in Indoor Air and
What’s (not) Being Done About It, Prev. Med. 31:631–637
[Received March 4, 2002; accepted May 14, 2002]
JAOCS, Vol. 79, no. 8 (2002)
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... Merrill], a legume grown mainly in tropical, subtropical and temperate regions, is one of the crops being targeted for introduction into environments, with arid and semi-arid climates, through both conventional and modern breeding approaches (Faisal, Yield Performance and Stability Analysis of Promising Soybean Genotypes under Contrasting Environments in the Semi-arid Zone... Ngalamu et al., 2009). In addition to providing an inexpensive source of protein and fats and natural nitrogen fertilisation for the soil (Ngalamu et al., 2012;Foyer et al., 2016), soybean is also an important crop from which industrial products such as edible oils, wax, paints, dyes and fibre are derived (Rezaei et al., 2002;Raghuvanshi and Bisht, 2010). Moreover, meat substitutes based on soybean are extensively used by vegan and vegetarian consumers (Messina and Messina, 2010;Raghuvanshi and Bisht, 2010). ...
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Background: The challenge to food security posed by climate change and coupled with the substantial rise in the global population, necessitate a shift in crop improvement programmes towards developing crop cultivars with stable and high yield potentials across a wide range of agro-ecological conditions. Methods: New high yielding crop varieties with stable performance across environments are enabling the expansion of their production area into non-traditional environments with semi-arid climates. Soybean (Glycine max L.), a tropical leguminous crop, has received significant attention as a target crop in breeding programmes for adaptation to semi-arid environments, due to its low water content, high nutritive value and the capacity to produce a variety of products. The objective of this study was to asses yield performance and stability of promising soybean genotypes under contrasting environments in the semi-arid zone of Sudan. We evaluated five soybean genotypes using a split plot design with environment as the main plot and genotype as the subplot. Result: Combined ANOVA showed significant differences among the genotypes, environment and genotype x environment interaction. Moreover, significant positive relationships were observed between seed yield and number of days to 95% flowering, 100-seed weight, leaf area and number of pods per plant. AMMI stability values revealed significant differences among the genotypes and genotype-by-environment main effects for seed yield. Similarly, results of GGE biplot showed significant contributions of genotypes and genotype-by-environment main effects. The stability models enabled us to identify genotypes with superior performance to specific environments. TGX 1904-6F, was found to be the most stable genotype with appreciable seed yield and adaptability across all environments that can be recommended for release to farmers in semi-arid Sudan.
... in the wax. A similar composition has been reported by others [28] . ...
In this work, pillar candles are examined with eight varieties of candle wick having lengths from 1.0 mm to 19.5 mm and diameters from 1.4 mm to 3.2 mm using paraffin wax, beeswax, and soy wax as fuels. Experiments were undertaken to measure burning rate, flame height, flame width, and melt pool diameter using video and gravimetric analysis. Several properties of candle waxes were examined to understand their impact on burning rates and flame shapes. A model is proposed using the Spalding B-number with a novel wick efficiency model for burning rate accurate to ± 1.7 g/h (± 46%). The selection of wick was observed to have a strong impact on the burning rate of the candle flame. The Roper model for diffusion flames was found to provide a suitable estimate for the upper limit of flame lengths, and with the modification proposed in this work it can be used to predict candle flame lengths to within ± 10.4 mm. The width of candle flames was modelled using the Froude number and wax vapour specific gravity and was found to be accurate to within ± 1.69 mm (± 38%). The wick selection had no significant impact on the flame length or width external to its impact on burning rates. A numerical model for the diameter of the wax melt pool of a candle is presented and can be used to extend manufacturer data on melt pool sizes to other waxes. A simplified model is presented to relate the size of the melt pool to the heat release rate for various waxes.
... Hence, with the abundance and low production cost of soybean and soybean oil, soybean wax should be explored more to manifest its hydrophobic properties and improve the quality of current wax consumption industries. For example, paraffin waxes and soybean waxes are typically used to make candles and many consumers are turning towards soybean wax because of the cleaner and longer lasting burn that soybean wax candles provide (Rezaei et al., 2002). Other applications include developing food packaging items made from soybean wax because of its hydrophobicity, which can improve the shelf life of perishables and are less toxic because of the plant derivatives in the wax. ...
A characterization study was conducted to obtain and analyze the thermal, chemical, and mechanical properties of industry grade wax soybean (Glycine max) for coating soy hull fibers from soybean processing in order to incorporate the soy wax coated soy fibers in additive manufacturing applications. The waxes when coated onto soy hull fibers are expected to better the fiber-polymer interface to produce additive manufacturing filaments with improved mechanical properties to be printed using fused filament fabrication technique. The printed parts can then be used in the automotive industry because the parts will be more sustainable, have less carbon footprint, and increased mechanical properties. The information obtained from this characterization study will be the preliminary step to determine the suitability of the waxes for fiber coating application. Applying soybean waxes in this manner increases the value of soybean waxes from being a source for candle making to being incorporated in manufacturing parts. Four wax samples were analyzed by thermogravimetric analysis, differential scanning calorimetry, viscometry, Fourier Transformed Infrared Spectroscopy, X-Ray Diffraction, Vickers micro-hardness testing, compression, and flexural testing. One sample was chosen with the most suitable properties for polymer composites and 3D printing filaments were produced.
The aim is to replace mineral waxes with vegetable fats as an organogel for candle manufacturing while keeping the same texture. The physico‐chemical characteristics of renewable vegetable raw materials differ from those of mineral waxes and consequently the structure of the blends in which they are used is modified. Their properties are measured at different scales using FT‐IR analysis, polarized light microscopy, calorimetry and rheology. The addition of 12‐hydroxystearic acid (12‐HSA) promotes the creation of hydrogen bonds within the rapeseed oil that makes possible its incorporation to form an organogel. The addition of 12‐HSA also results in a modification of the crystal microstructure of blends made of 90% vegetable raw materials. Hence, the crystal lattice is denser and the crystal size is reduced compared to blends including mineral waxes. At a macroscopic scale, the physical properties of blends with 12‐HSA are modified compared to the reference one, mainly made of mineral waxes. A modification of crystallization and melting temperatures as measured by differential scanning calorimetry as well as the rheological behavior and the hardness assessed by penetrometer are observed. This results in a higher stability against exudation for blends with a high content of 12‐HSA. Mineral waxes can thus be substituted in the formulation of candles by renewable materials for the use of organogel, via the incorporation of an organogelator, 12‐HSA.
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Weather in Malaysia are hot and humid throughout the year thus having a sudden rain can disrupt the drying of laundries and make them wet. In this study, an automated retractable roof system was developed to overcome this problem. The development and implementation of this study enables user to monitor the parameters at the laundry suspension area by using their smartphone and prevent the laundries getting wet from rain. This study uses humidity sensors, Ultraviolet (UV) sensor, rain sensor, and temperature sensor to detect parameter such as humidity, UV intensity, presence of water and temperature respectively. Data from the sensors were collected and analysed to determine the values of parameters when rains occurred. These parameters were indicated as part of weather prediction study. From experiment, the retractable roof will open and close depended on condition met by the system. In addition, the system can communicate with the user’s phone through using Internet connection. The Blynk application in the smartphone allows the user to monitor and control the system through internet connection between the application and microcontroller. This study will be helpful for non-commercial use and can be expanded to commercial use as with further improvement.
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Aromatherapy candles with essential oils which can provides a therapeutic treatments have been made to maintain and improve our wellbeing. In this paper, a mini prototype of automated aromatherapy candle process plant using IoT and WSN has been proposed and developed. The main process of producing aromatherapy candle are heating and mixing. To produce the right quality of the aromatherapy candle, the quantity of the raw material is important. Heating process will be control by using ESP8266 based PID controller and monitored by using Open Source Programmable Logic Controller called OpenPLC that run on Raspberry Pi. The software is efficient because can support users over the entire plant and process. Mixing process will mix the raw material evenly using agitator motor with specific temperature. The whole process in this work can be monitored and control through PC via this implementation of software. To obtain the best quality of this work, the set point of temperature need to be control and the plant able to be achieved after second test of the study. As the result, this study able to produces aromatherapy candle with better quality in minimal time. This study also able to control the candle from releasing too many Volatile Organic Compound that can effect human life. Armed with the wealth of relevant information presented in this article, it is hoped that readers will have greatly benefited and gained a thorough understanding on how to develop an automated aroma therapy candle process planting using IoT and WSN. With further research put forth into this study, it is also hope it could be an advantage in innovation development and can be implemented in real life manufacturing industry.
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LPKA Kelas II Bandung merupakan lembaga pendidikan bagi anak yang berkonflik dengan hukum di daerah Provinsi Jawa Barat. Berbagai upaya pembinaan dilakukan LPKA berkerjasama dengan berbagai pihak salah satunya adalah Perguruan Tinggi sebagai tenaga pengajar kegiatan non-formal. Kegiatan pelatihan pembuatan lilin aromaterapi ditujukan untuk menambah keterampilan para peserta anak didik pemasyarakatan (andikpas) sebagai bekal keterampilan individu sehingga dapat digunakan kelak setelah kembali ke lingkungan masyarakat. Kegiatan diawali dengan trial pembuatan produk di laboratorium sebelum pelaksanaan pelatihan. Pelatihan disampaikan dalam bentuk presentasi dan dilanjutkan dengan praktik pembuatan lilin aromaterapi secara eksperimentatif dalam berbagai variasi bentuk. Produk berupa lilin aromaterapi yang berfungsi ganda, yaitu sebagai alat penerangan, media terapi dan penyegar ruangan. Kegiatan pelatihan membuat suatu produk yang memiliki nilai ekonomis tinggi melalui pembuatan lilin aromaterapi berbasis soy wax dalam wadah gelas dapat memiliki nilai jual yang tinggi. Hasil pengabdian menunjukkan bahwa kegiatan pelatihan mampu memotivasi peserta andikpas untuk berwirausaha dan peserta antusias mengikuti selama kegiatan pelatihan berlangsung.
The female sexual hormone, 17β-estradiol (E2), was chosen as a model emerging contaminant to study its degradation kinetics using UV-activated persulfate (UV/PS). Our objective was to quantify the effectiveness of UV/PS coupled with slow-release technology to degrade E2 in real wastewater using a systematic design flow-through system. This was accomplished by quantifying the effects on E2 degradation rates of the initial PS or E2 concentration, initial pH, constituent ions, turbidity, humic acids, and real wastewater. The results showed that the E2 degradation rates increased with increasing PS concentration. The presence of other constituent ions (NO 3⁻ , Cl ⁻ , HCO 3⁻ ) resulted in varying degradation rates due to the formation of active and less reactive radicals. Humic acid had higher significant impact on the rates than did turbidity. In addition, the observed degradation rates (0.140 min ⁻¹ ) in Deionized water were much higher than those observed in real wastewater matrix (0.001 min ⁻¹ ). Biodegradable soywax was the best binding agent that provided sustained delivery of PS thus resulting in better E2 removal than with other waxes. But treating E2 with PS soywax in a wastewater matrix, our flow-through system was able to maintain the E2 concentration below 50% in the contact tank (150 min) and able to continually remove E2 up to 65% (240 min) in the effluent reservoir. The overall results supported the use of UV-activated slow-release PS to treat discharge water in animal farming.
A series of source tests were conducted on the combustion of paraffin and beeswax candles. An enclosed chamber sampling system was utilized, and fine particle samples were collected on both quartz fiber and Teflon filters. Electronic particle sizing was performed using an optical particle counter and a differential mobility analyzer. Filter samples were weighed to determine fine particle mass emission rates and then analyzed for elemental carbon and organic carbon by thermal evolution and combustion analysis and for organic chemical composition by GC/MS. Three modes of candle burning were observed with very different emission profiles: a “normal burning” mode characterized by low mass emission rates and particles smaller than 100 nm in diameter; a “sooting” behavior with high emission rates of predominantly elemental carbon particles; and a “smoldering” phase upon candle extinction during which most of the mass emissions occurred as white particles having diameters between 400 and 800 nm. The majority of emissions were organic compounds including alkanes, alkenes, alkanoic acids, wax esters, cyclohexylalkanes, and alkanals. Analysis of the unburned waxes revealed that while some of these compounds were thermally altered products of the unburned wax, many others were unaltered candle components emitted by direct volatilization. Thus, possible chemical tracers for candle burning may be easily identified by analyzing unburned wax material. The information provided in this study, in conjunction with future ambient indoor air sampling programs and receptor-oriented chemical mass balance techniques, can be used to determine the relative importance of candle burning to indoor soiling problems.
2,4,6-Trichlorophenylhydrazine was tested as a reagent for carbonyl compounds. As little as 0.1 of the 2,4,6-trichlorophenylhydrazones (2,4,6-TCPH) could be measured with an electron capture detector, so this reagent should be useful in measuring the carbonyl compounds in oxidized fats at levels near their flavor thresholds. Mixtures of 2,4,6-TCPHs were separated by thin layer chromatography. Alkan-2-one-2,4,6-TCPHs were separated from aldehyde-2,4,6-TCPHs on alumina plates. The alkanal, alk-2-enal and alk-2,4-dienal-2,4,6-TCPHs were separated from each other either on silica gel plates or silica gel-silver ion plates. The derivatives within each carbonyl class were separated by chain length on chromatography media impregnated with phenoxyethanol. The 2,4,6-TCPHs eluted from thin layer plates were determined with an electron capture detector after gas chromatography on a 30 cm column of freeze-dried detergent base coated with a silicone oil.
Polychlorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF) selected chlorinated pesticides, polycyclic aromatic hydrocarbons (PAH) and some volatile organic compounds (VOC) were analysed in the exhaust fumes of candles made from different waxes and finishing materials. To guarantee defined burning conditions a chamber was developed for the sampling of the exhaust fumes. Using a simple exposure model, the inhalative uptake of PCDD/PCDF by an adult person was calculated for different scenarios. It was shown that additional uptake of PCDD/PCDF caused by candle emissions does not contribute significantly to the total daily intake of these compounds. Emissions of PCDD/PCDF, benzo(a)pyrene and the VOC were then compared to limit value for working places. Even when many candles would be burnt at the same time in a small room, concentrations of the compounds investigated stay below 1% of the tolerable limit values.
Background: Since the inception of the environmental movement early in the 1970s, the majority of regulation, laws, and standards regarding pollutants have focused on the release of pollutants into our air and water rather than on the extent of exposure. As a consequence, the actual amounts of toxic pollutants to which humans are continually exposed have long been ignored. Moreover, regulation and assessment of pollution have focused primarily on ambient environmental levels. This fails to adequately examine the state of indoor air. This is of particular concern and deserving of more attention, considering that a majority of people spend the majority of their time at home, Results: Studies on indoor air quality suggest that, within the home, people are exposed to high levels of numerous pollutants. Of particular concern are the levels of polycyclic aromatic hydrocarbons and volatile organic compounds because many of these are known carcinogens. While the need for further study is clear, what evidence there is already warrants the establishment of indoor air regulation and the implementation of preventive measures. For such measures to be effective, a great deal of education and outreach will be necessary. Also, health care providers must play an active role.
Acrolein, in Environmental Health Criteria 127, World Health Organization
  • T Vermeire
Vermeire, T., Acrolein, in Environmental Health Criteria 127, World Health Organization, Geneva, 1992, pp. 11-14.
Characterization of Scented Candle Emissions and Associated Public Health Risks
  • J D Krause
Krause, J.D., Characterization of Scented Candle Emissions and Associated Public Health Risks, Ph.D. Dissertation, University of South Florida, 1999.