CORN DRYING IN CANADA USINGAMBIENT AIR

R.A. Treidl

Member CSAE

Superintendent for Agricultural and Forest MeteorologyAtmospheric Environment Service, D.O.E.

Downsview, Ontario

INTRODUCTION

Ages ago, agriculturists discovered thatcom kernels need to be dried to increasethe storage life. European peasants usedto tie two ears together by the sheathsand hang them in rows under the roofoverhang with the odd ear of Indian cornproviding an interesting touch of color.As the quantity of com grown increased,much the same drying effect wasobtained by placing ear com in cribs.With the advent of the field picker-sheller, large quantities of shelled comwere put into storage at unsafe moisturecontents. Several methods and combina

tions of methods of drying shelled comhave evolved to dry high-moisture shelledcom. Another alternative is to preventspoilage by treating com with a preserving acid. All of this adds to the cost ofproducing corn. Accordingly, the interestin air drying com has remained. Thispaper examines the drying potential ofthe air, relying on theoretical formulaeand on climatological data for a numberof representative stations in the presentCanadian com belt and also in regionswhere the growing of kernel corn is stillawaiting the development of hardierhybrids.

THE ECONOMICS OF CORN DRYING

Desilets and Henaulta recently investigated the cost of drying corn usingpropane heaters in the province ofQuebec. To lower the moisture contentof com from 30% wet base (WB) to14.5% adds a cost ranging from 11.6<t/bufor the larger, more efficient machines to18.3$/bu for small installations. Bothbatch drying and continuous drying

a Desilets, D. and M. Henault, 1972. Cost ofdrying corn. Paper No. 72-507, presented atthe Annual Meeting, Charlottetown, P.E.I.,June, 1972.

RECEIVED FOR PUBLICATION APRIL 10,1973

methods have been surveyed. In addition,large capital costs have to be borne,ranging from $7,440 for a dryer of600-ton capacity to over $50,000 for thelargest installations capable of handling5,000 tons and more. These costs areassumed to be typical for all of Canada.

In contrast to this, the operating costsof air dryers are from 3-6$/bu accordingto Bloome (1), depending on fan efficiency, and increasing rapidly withgreater grain depth in the bin. The capitaloutlay is limited to the cost of a suitablysized bin and one fan and motor ofsuitable size. Modifications of these

systems are possible, to take advantage ofperiods of low relative humidity of theoutside air. This could be done by theaddition to the system of a "humidistat"that turns the fan motor on or off as

required when the relative humidity ofthe outside air changes.

Thus it would appear that theinstallation of an air drying system forkernel com would represent a possibilityfor com farmers to save perhaps 10<t/buover heated-air drying and thereby putthem in a more competitive position inthe market place. This, of course,depends on the feasibility of usingambient (outside) air for com drying.

PROBLEMS OF CORN STORAGE

Once com is harvested, it must beprotected from spoilage. Rotting ofkernels is caused by mould and otherorganisms that feed on them. Thedevelopment rate of these organisms is afunction of both temperature and moisture content of the outside air, which alsoinfluence the moisture content of thekernels. The moister the kernels, thefaster they will spoil. Thus, according toShove (2), corn of 30% moisture contenthas a storage time of only 3 d at 70°Fincreasing non-linearly to 3 wk at 40°F,whereas com of 20% moisture contentcan be stored for 2 wk at 70°F, 4 wk at60°F, 7 wk at 50°F and indefinitely at40°F.

CANADIAN AGRICULTURAL ENGINEERING, VOL. 16, NO. 2, DECEMBER 1974

Planting date influences the moisturecontent at harvest time: 3-yr averagesderived from trials conducted at Urbana-Champlain, Illinois have shown that whencorn is planted on May 1, it will have amoisture content of 23% by September30; but when planted later, say on June1, it will have a moisture content of 36%.This marked difference in moisture

content tends to diminish somewhat laterin fall, as found at Champlain-Urbana,Illinois, but 1 mo later (October 30) it isstill 8%, with corn planted at the earlydate showing 17% and the later planting25% moisture content. Similar results

may be expected in Southern Ontario.

This, of course, means that the kernelshave to be dried as fast as possible afterplacing them in the bin to ensure themaximum length of storage withoutspoiling. Air ventilation can be promotedby screening the kernels in order toremove fine material. The recommended

fan horsepower according to Shove (3),from 3 hp for a bin of 16 ft diam andholding 2,700 bu to a depth of 16 ft, to20 hp for a large bin (40 ft diam) holding20,000 bu with a kernel depth of 20 ft.Small heaters capable of raising the airtemperature 5°F above the outsidetemperature are recommended. The heatof the fan motor will raise the airtemperature 2°F, in addition.

The speed of drying is largely afunction of the rate of air flow at a givenambient temperature and relative humidity (RH). At 40°F and 65% RH forinstance, shelled corn at 30% moisturecontent (WB) will take 92 d at a flow rateof 1 ft3 per min, 46 d at 2 cfm and 30 dat 3 cfm to be dried to 17% (WB). From20 to 17%, the drying periods are,respectively, 19, 10 and 6 d.

It is important to understand that thestorage life spent cannot be replaced:thus the need to lower the moisture

content as quickly as possible, especiallyat high outside temperatures.

Thus, recent research has shown that:

(1) the storage life of wet shelled

96

com can be greatly extended bymaintaining low storage temperature; and

(2) substantial drying can be accomplished at low temperatures.

Therefore, it is necessary to know thedrying potential of the air and tounderstand the day-to-day and month-to-month changes in temperature andhumidity of the outside air.

Sabbah (4) presented a formuladeveloped by Henderson (3) for theequilibrium moisture content (Me) ofcorn as a function of the air temperature(T) and relative humidity:

Me(%DB) •[:loge (1 -RH) .507

6.512 X 10~6 X T*\(Henderson)

where RH is to be expressed in decimalform, and r* =°F +460, the absolutetemperature in Fahrenheit degrees (T°F=9/5T°C +32).

This formula yields good results, butbreaks down for relative humiditieshigher than 90% as the equilibriummoisture content then tends to infinity.This disadvantage was sidestepped bySabbah (4) who developed a formulawhich gives values that are in goodagreement, within the RH range 80-90%,with the Henderson formula and, moreover, also with observed moisture contentreadings of com stored at relativehumidities ranging from 90-100%. Thisformula is:

Me (%DB) =0.01822(RH*) 1.72

jt>.i

(Sabbah)

where RH* is expressed as a percentageand Tas the actual temperature indegrees Fahrenheit.

A computer project was initiated withthe object of determining the protentialdrying power of the ambient air and theextent of its variations for each week ofthe year for a number of hourly observingstations across the breadth of Canada.

Ten years of hourly data resulted in1,680 observations of dry-bulb temperature and relative humidity for each weekof the year. These were used to determinethe equilibrium moisture content forshelled corn in bins, based on Henderson's formula for RH < 80% andSabbah's formula for RH>80%. Themeans and standard

found for each week

graph paper. Smoothing was necessarybecause of the erratic week-to-week

variations in the Me values: 5-wk running

97

deviations were

and plotted on

EQUILIBRIUM MOISTURE CONTENT FOR SHELLED CORN TORONTO MALTON A. ONT.

+ ONE STD. DEVIATION

+ ONE STD. DEVIATION

MEAN (24 HOURS)

MEAN (DAYLIGHT HOURS

0600-1800 LST)

- ONE STD. DEVIATION

- ONE STD. DEVIATION

0 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54

| JAN. | FEB. | MAR. | APR. | MAY | JUNE | JULY | AUG. | SEPT. | OCT. | NOV. | DEC. |WEEKS OF THE YEAR

Figure 1. Annual variation of equilibrium moisture content of shelled corn at Toronto International Airport (Malton, Ontario: solid curves, all hours of the day; broken curves, forthe 12-h period 0600-1800 LST. All curves smoothed by use of 5-wk running means.

EQUILIBRIUM MOISTURE CONTENT FOR SHELLED CORN

—I 1 1 1 1 1 1 1

JAN. | FEB. | MAR.15 18 21 24 27 30 33 36 39 42

APR. | MAY | JUNE | JULY | AUG. | SEPT. | OCT. |45

NOV.

REGINA A. SASK.

V ONE STD. DEVIATION

I- ONE STD. DEVIATION

MEAN (24 HOURS)

MEAN (DAYLIGHT HOURS)

- ONE STD. DEVIATION

- ONE STD. DEVIATION

54 WEEKS OF THE YEAR

Figure 2. As in Figure 1, for Regina Airport, Saskatchewan.

CANADIAN AGRICULTURAL ENGINEERING, VOL. 16, NO. 2, DECEMBER 1974

EQUILIBRIUM MOISTURE CONTENT FOR SHELLED CORN portage la prair.e a. man means reSulted in smooth annual varia

tions.26 -

25

0 3 6 9 12 15 18 21 24

| JAN. | FEB. | MAR. | APR. | MAY | JUNE JULY | AUG. | SEPT. | OCT.45 48 51

NOV. | DEC. |

I- ONE STD. DEVIATION

(- ONE STD. DEVIATION

MEAN (24 HOURS)

MEAN (DAYLIGHT HOURS)

- ONE STD. DEVIATION

- ONE STD. DEVIATION

54 WEEKS OF THE YEAR

Figure 3. As in Figure 1, for Portage la Prairie Airport, Manitoba.

EQUILIBRIUM MOISTURE CONTENT FOR SHELLED CORN FREDRICTON A. N.B.

+ ONE STD. DEVIATION

+ ONE STD. DEVIATION

MEAN (24 HOURS)

MEAN (DAYLIGHT HOURS0600-1800 LST)

- ONE STD. DEVIATION

^ ONE STD. DEVIATION

0 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 WEEKS OF THE YEAR| JAN. | FEB. | MAR. | APR. | MAY | JUNE | JULY | AUG. | SEPT. | OCT. | NOV. | DEC. |

Figure 4. As in Figure 1, for Fredericton Airport, New Brunswick.

CANADIAN AGRICULTURAL ENGINEERING, VOL. 16, NO. 2, DECEMBER 1974

The formulae yield the equilibriummoisture in terms of percent dry base(DB), whereas all calculations involvingcorn storage use percent wet base (WB);the values thus had to be converted to the

latter. The converted values then were

plotted on graph paper with timeabscissa, in terms of weeks, beginningJanuary 1st. The resulting plots give anidea of the variation during the weekunder consideration. Assuming a normaldistribution, 2 h in 3 during this weekwill cause equilibrium moisture contentthat falls between the mean and the mean

plus or minus one standard deviation; inother words, there is a 67% chance for itto occur in that range.

RESULTS

The annual variations in equilibriummoisture content at 27 points scatteredthroughout Canada may be grouped intofour principal types which are shown inFigures 1 through 4. Location namesfollowed by the letter A denote airportobservation sites.

These types appear to be due toclimatic influences and thus can be used

to classify the corn drying climate.Generally, the equilibrium moisture contents and standard deviations tend to a

winter maximum. It is during the warmpart of the year that the regionaldifferences are most pronounced.

Figure 1 shows the annual variation atToronto International Airport to have anearly sinusoidal character with a moderate amplitude. The summer minimumoccurs near July 1st. This type ischaracteristic for all of Southern Ontario

and Coastal B.C.

Regina, Figure 2, shows a doublesummer minimum; the first during May,the second early in August. A sharp riseoccurs in November. The amplitude isquite pronounced. This type prevailsacross the southern Prairies and interiorB.C.

Portage La Prairie, Figure 3, shows avariation with moderate amplitude and aclear-cut minimum in spring (May). Fromthen on, the curve rises slowly intoOctober, followed by a sharp rise inNovember. This curve is typical for thenorthern Prairies.

Figure 4 shows the annual variation atFredericton, New Brunswick. Here too,we find a May minimum, as in Figure 3,

98

TABLE I SMOOTHED WEEKLY MEANS AND STANDARD DEVIATIONS OF EQUILIBRIUM MOISTURECONTENT IN PERCENT WET BASE OF SHELLED CORN WITH 24 HOUR FAN OPERATION

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Weeks Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D

Jan.

01-07 22..5 2.9 20.3 2.9 21.5 3-5 19-7 3.5 17.8 4-5 17-2 3-6 23.0 2.7 20-9 2.7 20.8 3.1 21. 5 3-0 20.8 3-0 20.5 3-4 22.0 2-7 21.6 2.808-14 22.]L 3-1 20.3 3-1 21.2 3.9 19-7 3-5 17.9 4.6 17.2 3-6 23.2 2.8 20.8 2.7 20.8 3.0 21.4 2.9 20.7 3.0 20.4 3-5 22.1 2.8 21-5 2.915-21 22.() 3-2 20.2 3-3 20.9 3-9 20.0 3-3 18.3 4.6 17.4 3-7 23. 1 2.9 20.9 2.8 21.0 3.0 21. 5 3-0 20.8 3-2 20.3 3-4 21.9 2.8 21.6 2.822-28 21.1> 3.2 20.3 3-4 20.7 4.0 20.4 3-4 18.6 4.5 17.7 3-7 23.2 2.9 21.1 2.8 21.3 2.9 21.0 2.9 20.8 3-1 20.4 3-4 21.8 2.8 21.4 2.829-04

Feb.

05-11

21. £J 3-2 20.3 3-5 20.7 4.0 20. 5 3-5 18.7 4.6 18.0 3.9 23. 2 2.9 21.1 2.8 21.4 2.8 20.9 2.9 20.9 3.1 20.6 3-4 21.8 2.9 21.3 2-9

21.6 3-3 20.1 3-7 20.6 4.1 20.3 3.6 18.8 k.6 17.9 3.9 23. 3 3.0 21.0 2.8 21.3 2.9 20.7 3-0 20.6 3-2 20.7 3-3 21.7 2-9 21.1 2.912-18 21.£ 3-4 19.6 3-9 20.4 4.1 19.9 3.6 18.5 4.6 17-9 4.0 22. 5 3-0 20.9 2.9 21.1 2.8 20. + 3.0 20.5 3-2 20.6' 3-5 21.5 3-1 20.9 3.119-25 20. S> 3-3 19.2 4.1 20.2 4.2 19.6 3.6 18.4 4.4 18.0 4.1 22. 5 2.8 20.9 2.9 21.0 2.9 20.2 3-2 20.4 3-1 20.6 3.5 21.4 3-1 20.6 3.126-04

Mar.

05-11

20.6; 3.6 18.4 4.2 19-9 4.4 19.4 3.6 18.3 4.5 17.8 4.2 22. I 2.9 20.8 3.0 20.8 3.2 19.9 3-3 20.3 3.0 20.3 3-6 21.2 3.2 20.6 3-2

20.]L 3.6 17.8 4.5 19.4 4.4 19. L 3-6 18.0 4.5 17-5 4.2 22. 3 3-0 20.7 3.1 20.5 3.4 19-6 3-4 20.1 3-2 20.1 3-7 20.9 3.4 20.6 3-412-18 19-S> 3.5 17-5 4.5 19-3 4.3 19.0 3.8 18.0 4.7 17.4 4.6 21. 5 3-2 20.4 3.2 20.3 3.8 19-4 3.5 20.1 3-4 19-8 3.9 20.5 3-6 20.3 3.619-25 19.15 3.4 17-2 4.5 19.2 4.3 18.8 4.0 18.0 5.0 17.1 4.7 21.0 3-6 20.0 3.4 19-9 4.1 19-2 3-7 19.9 3.4 19-4 3-9 20.2 3-8 20.1 3-726-01

Apr.02-08

19-5 3.4 16.8 4.6 19.1 4.3 18. L 4.2 17-5 4.5 16.7 5.1 20.0 3-9 19.2 3.7 19-1 4.6 18.8 3-7 19-3 3-7 18.£ 4.2 19.6 4.1 19.7 4.0

19.2 3.3 16.3 4.5 19.0 4.3 17. + 4.4 17.3 5.4 16.5 5.3 19.0 4.3 18.4 4.0 18.4 4.8 18.4 3-7 18.7 3.8 18.5 4.3 19-2 4.3 19-2 4.209-15 19.]- 3.3 16.0 4.4 18.9 4.2 16. 5 h-5 16.9 5-5 16.2 5-2 18.2 4.8 17-8 4.5 17.9 5-0 18.3 3-9 18.3 4.1 18.2 4.4 18.9 4.5 18.6 4.416-22 18.6* 3.4 15-7 4.5 18.8 4.2 16.0 4.7 16.6 5-4 16.0 5.4 17-5 5-0 16.9 4.6 17.4 5.3 17.9 4.0 17.6 4.2 17- S 4.4 18.4 4.5 18.3 4.623-29 18.3 3.3 15-5 4.5 18.8 4.2 15- 5 4.7 16.3 5-3 15.8 5-3 l£.9 5-2 16.1 4.7 16.9 5-4 17.5 4.3 17.0 4.4 17.6 4.4 18.0 4.6 18.1 4.850-06 18.3 3.3 15-3 4.5 18.6 4.2 15.0 4.8 16.0 5-4 15-5 5-2 16.2 5-2 15.6 4-7 16.3 5.2 17.1 4.4 16.5 4.6 17-6 4.5 17.8 4.6 18.0 4.7May

07-13 18.2 3.4 15.4 4.6 18.7 4.2 14.7 4.8 15-5 5-3 15-3 5-2 15.8 5.3 15.1 4.8 16.0 5-4 16.7 4.7 16.1 4.8 17.^ 4.4 17.6 4-5 17.9 4.614-20 18.C 3.3 15.3 4.6 18.7 4.2 14.7 4.8 15-2 5-2 14.8 5-0 15.1* 5-2 14.7 4.9 15-4 5-2 16.5 4.8 15.8 4.8 17.1 4.2 17-5 4.4 17-8 4.521-27 18.c 3.2 15.2 4.5 18.6 4.1 14.7 4.6 15.0 5-2 14.7 5-0 15. 5 5.3 14.7 4.9 15.3 5.3 16.7 4.8 15.8 4.8 17.2 4.2 17.6 4.3 17.8 4.528-03 18.C 3.2 15-2 4.4 18.6 4.1 14.9 4.6 15.O 5-0 14.7 5-0 15.3 5.1 14.9 4.9 15-3 5-1 16.7 4.7 15.8 4.8 17-3 4.2 17.6 4.2 18.0 4.4

June

04-10 18.c 3.2 14.8 4.2 18.6 4.1 15.1 4.4 15.3 5-0 14.8 4.9 15.6 5.1 15.0 .4.9 15.7 5-2 16.8 4.5 16.1 4.7 17-2 4.1 17.6 4.1 18.1 4.311-17 17.s 3.2 14.6 4.0 18.4 4.0 15-5 4.3 15-7 5-0 14.9 4.9 15.9 4.9 15.4 4.9 15-8 5-1 17.0 4.3 16.3 4.4 17-1 4.0 17-6 4.1 18.3 4.318-24 18.c 3.2 14.7 4.1 18.5 4.0 15-7 4.3 15.8 4.9 15.0 4.8 16.0 4.9 15.5 4.9 16.0 5-0 17.0 4.1 16.5 4.5 17-1 4.0 17-5 4.1 18.2 4.225-01 18.c 3.2 14.3 4.0 18.4 4.2 15.8 4.2 15.8 4.8 14.9 4.7 16.1 4.8 15.6 4.7 15-9 4.8 17.O 4.0 16.6 4.2 17.1 3-9 17.4 4.1 18.3 4-3July02-08 18.C 3.2 13.9 3.8 18.4 4.2 15.9 4.2 15.6 4.6 l*.5 4-5 16.0 4.7 15-5 4.6 15-6 4.6 17-2 3-9 16.8 4.1 17-1 3.8 17.4 4.1 18.3 4.409-15 18.2 3-2 13.9 3-8 18.^4 4.2 16.1 4.1 15-5 4.5 14.2 4.4 15.8 4.7 15.5 4.5 15-3 4.6 17-4 3-9 16.8 4.0 17-3 4.0 17-5 4.2 18.4 4.416-22 18.3 3.1 13.9 3.8 18.4 4.3 16.1 4.1 15.5 4-5 14.1 4.3 15.5 4.6 15.5 4.5 15.0 4.5 17.4 3.9 16.9 4.0 17-5 3-9 17-6 4.1 18.5 4.323-29 18.3 3.2 13.8 3-8 18.4 4.4 16.2 4.1 15.5 4.5 14.1 4.3 15.3 4.6 15-5 4.5 14.7 4.5 17-3 3-8 16.8 3-9 17. e 3-9 17.9 4.1 18.8 4.330-05 18.5 3.2 14.0 3.8 18.5 4.3 16.5 4.2 15-5 4.5 14.0 4.4 15.1 4.6 15-5 4.6 14.5 4.5 17.4 4.0 16.7 4.0 17.8 3-8 18.1 4.1 19.0 4.3

Aug.06-12 18.8 3.1 14.3 3-9 18.6 4.4 16.7 4.3 15-8 4.6 14.2 4.5 15.1 4.7 15.6 4.8 14.5 4.7 17-4 3.9 16.8 4.1 18.2 3-9 18.4 4.1 19-1 4.313-19 19.C 3.2 14.7 4.1 19-0 4.3 16.9 4.3 15.9 4.6 14.5 4.7 15.4 4.9 16.0 5-0 15.O 4.8 17.8 4.0 17-1 4.2 lfl.lt 3-7 18.7 4.0 19.2 4.220-26 19.1 3.2 15-0 4.1 19-2 4.4 17-1 4.3 15-9 4.7 14.7 4.7 15.6 4.8 16.1 4.9 15-3 5-1 18.0 3-9 17.4 4.3 18.6 3.8 18.8 4.1 19.4 4.227-02 19.^ 3.2 15.3 4.1 19.4 4.3 17.4 4.4 16.2 4.9 15.1 4.9 15.9 4.9 16.5 4.9 15-7 5.1 18.£ 4.0 17-4 4.2 18.5 3-8 18.8 4.1 19.4 4.2

Sept.

03-09 19.7 3.2 15.8 4.3 19.8 4.3 17-? 4.3 16.5 4.9 15-5 5-0 16.3 5-0 16.7 4.9 16.2 5.2 18.4 4.0 17.6 4.3 18.9 3-8 19-1 4.1 19.5 4.110-16 20.C 3.1 16.2 4.3 20.1 4.3 17.4 4.3 16.4 4.9 15-7 5.0 16.7 4.9 16.9 4.8 16.5 5.2 18.4 4.1 17.6 4.3 18.8 3-8 19.2 4.0 19.8 4.017-23 20.3 3.2 16.5 4.3 20.1 4.2 17- 2- 4.3 16.1 5-0 15-5 5-1 16.8 4.9 16.9 4.8 16.3 5-1 18.3 4.1 17.4 4.3 18.6 3.8 19.0 4.0 19.8 3-924-30 20.7 3.1 17-1 4.3 20.4 4.1 17.2 4.4 16.3 5.0 15.8 5-2 17.I 4.9 17.0 4.6 16.6 4.9 18.4 4.1 17-5 4.3 18.6 3-9 19-1 4.0 19-9 3-9

Oct.

01-07 21.1 3.0 17.4 4.3 20.7 4.0 16-9 4.3 16.0 5-0 15.5 5-0 17-3 4.9 16.9 4.5 16.6 4.9 18.6 4.1 17.5 4.4 18.7 4.0 19.2 4.0 20.1 3-908-14 21.1) 2.9 18.0 4.4 20.8 3.9 16.9 4.3 15-9 5-0 15.5 5-1 17.6 4.9 17.3 4.6 16.8 4.9 18.6 4.1 17.6 4.4 18.5 4.0 19.3 4.0 20.1 3.815-21 21.6 3.0 18.2 4.3 20.9 3.8 16.9 4.3 16.0 5.0 15-5 5.0 17.8 4.8 17.5 4.4 17.1 4.8 18.8 4.1 17.6 4.3 18.6 4.0 19-4 4.0 20.2 3.822-28 21.8 2.9 18.6 4.2 21.1 3.7 17.3 4.2 16.4 5.0 16.0 4.8 18.2 4.6 18.0 4.1 17.6 4.6 19.0 3-8 17.9 4.1 18.9 4.0 19.8 3-8 20.6 3.729-04 21.fi 3.0 18.8 4.1 21.1 3.7 18.0 4.1 17.1 5.0 16.5 4.7 18.9 4.2 18.9 3-9 18.4 4.5 19.4 3-6 18.4 3-9 19.2 3-9 20.1 3-7 20.8 3.4

Nov.

05-n 2i.e 3.0 19.0 3-8 21.1 3-7 18.8 4.1 17.7 4.8 17.O 4.5 19-9 3.9 19.8 3-7 19-2 4.2 19.S 3.4 18.9 3.6 19.^ 3-9 20.4 3-6 21.2 3-212-18 21.fi 3.0 19.2 3-7 21.0 3-6 19-1 3-8 18.0 4.6 17-1 4.1 20.6 3-6 20.4 3-5 19.7 3-9 20.4 3-3 19.4 3-4 19-5 3.7 20.5 3-4 21.4 3.2

19-25 21.S 2.8 19.6 3-5 21.1 3.5 19.4 3.6 18.2 4.5 17.4 4.1 21.3 3.3 20.9 3-2 20.0 3.6 20.8 3-0 20.1 3-3 19.9 3.7 20.9 3.3 21.8 3-026-02 22.1 2.9 19-8 3-3 21.2 3-5 19-7 3-5 18.3 4.4 17-6 4.0 22.0 3-1 21.4 3-0 20.4 3-5 21.£ 3-0 20.5 3.1 20.3 3-6 21.1 3.1 21.8 2.8

Dec.

03-09 22.2 2.7 20.2 3-2 21.4 3.4 19.5 3-5 17-9 4.3 17.4 3.8 22-3 2.9 21.4 2-9 20.4 3-3 21.4 2.9 20.8 3.0 20.6 3.5 21.4 3.0 22.0 2.8

10-16 22. k 2.7 20.4 3-1 21.6 3-2 19-^ 3-3 17.8 4.2 17.2 3-6 22-5 2.8 21.4 2.8 20.5 3-1 21.6 2.9 20.9 2.9 20.9 3-5 21.7 2.9 22.0 2.8

17-23 22.5 2.6 20.5 2.9 21.8 3.3 19-6 3-5 17-8 4.5 17.2 3-6 22.8 2.7 21.3 2.6 20.6 3-2 21.7 2.9 21.0 2-9 20.9 3.4 22.1 2.8 22.0 2.824-30 22.5 2.7 20.6 2.8 21.8 3-3 19.6 3-6 17-6 4.4 17.2 3.6 23.0 2.7 21.2 2.7 20.6 3.1 21.8 2.9 21.0 3.0 20.8 3-4 22.1 2.7 21.8 2.8

31- 22.U 2.8 20.5 2.9 21.8 3-3 19.6 3.5 17-8 4.5 17.2 3-7 22.9 2.8 20.9 2.6 20.7 3.1 21.- 2.9 20.9 3-0 20.7 3.3 22.1 2.7 21.7 2.8

but the amplitude is much reduced,indicating a maritime influence. Theequilibrium moisture content increasessteadily from then on to reach amaximum early in december. This typeshows a fairly high moisture content andhence a poor drying potential in autumn.It prevails throughout the Maritimes,central Quebec, and extends into centralOntario whence it gradually blends intothe type shown in Figure 3.

Table I shows weekly values of the

99

equilibrium moisture contents and standard deviations for all stations that have

been analyzed in this project.

A reduction in the final moisture

content when drying corn can be effectedby switching the fan motor on during thedaylight hours only, which normallyshow higher temperatures and lowerrelative humidity readings. Since thenumber of hours of fan operation arehalved, drying will be slower if this isdone early in the fall; experience has

shown that it is best to run the fan

continuously until the equilibrium moisture content is approached and then torun it only during the daylight hours so asto achieve a lower final moisture content.

Accordingly, a second computer projectwas used to determine the equilibriummoisture content based on operation ofthe fan motor between the hours

0600-1800 LST, all other conditionsunchanged. The results can be seenlikewise in Figures 1-4 and in Table II. Itwill be noticed that the daylight values

CANADIAN AGRICULTURAL ENGINEERING, VOL. 16, NO. 2, DECEMBER 1974

TABLE I (CONT'D) SMOOTHED WEEKLY MEANS AND STANDARD DEVIATIONS OF EQUILIBRIUM MOISTURECONTENT IN PERCENT WET BASE OF SHELLED CORN WITH 24 HOUR FAN OPERATION

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Weeks Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D

Jan.

01-07 20.6 3-2 19.6 3-1 21-5 3-2 20.1 3-5 21.2 2.8 19.7 3-1 20.3 2-9 20.3 3-5 20.0 3.4 19-6 3-6 21.8 3-3 20.5 3-2 21.9 2.9

08-14 20.6 3-4 19-5 3-2 21.4 3.2 20.0 3-6 21-3 2.9 19-5 3-2 20.2 3.0 19-9 3-4 20.0 3.5 19-4 3-6 21.5 3-3 20.4 3-3 21.8 3-1

15-21 20.4 3.4 19-3 3-3 21.2 3.4 19-7 3.6 21.1 2.8 19-3 3.3 19-9 3-0 19.9 3-4 19-8 3-6 19-1 3-7 21.2 3-5 20.3 3.4 21.6 3-1

22-28 20.4 3-5 19-4 3-4 21.1 3-5 19-5 3-7 21.1 2.9 19.2 3.4 19.7 3.0 19.8 3-5 19.8 3.6 19-1 3-8 21.1 3-5 20.3 3-4 21.6 3-1

29-04 20.3 3-5 19-3 3-5 21.1 3.7 19-6 3-7 21.0 2.9 19-3 3-3 19-9 3-2 19-7 3-5 19-9 3-7 19-I 3.8 20.9 3-5 20.2 3.5 21.4 3-2

Feb.

05-11 20.2 3-6 19-2 3-5 21.1 3.8 19-4 3-9 20.9 3.0 19-3 3-4 19-9 3-2 19.5 3-6 19-8 3-7 19.0 3-9 20.8 3-7 20.2 3-5 21.4 3-2

12-18 20.0 3-6 19-1 3-5 20.8 3-9 19.2 3-9 20.6 3.0 19.4 3-4 19.8 3-2 19-4 3-7 19.5 3-7 18.9 3-8 20.7 3-6 20.0 3-5 21.5 3-1

19-25 19-9 3-7 18.8 3-5 20.3 4.0 18.8 3-9 20.4 3.2 19-4 3-6 19.8 3-3 19.0 3-7 19.1 3-7 18.8 3.8 20.7 3.6 19.8 3-6 21.7 3.0

26-04 19.9 3-9 18.7 3-6 20.1 4.1 18.5 3.9 20.3 3.4 19.4 3.6 19.7 3-5 18.6 3-7 18.8 3-7 18.5 3.8 20.6 3-8 19.5 3-6 21.6 3-0

Mar.

05-11 19-9 3-9 18.6 3-8 19.7 4.1 18.1 3-9 20.1 3.4 19.2 3-7 19-5 3.5 18.3 3-8 18.4 3-7 18.5 3-8 20.6 3-9 19.4 3-8 21.7 3-1

12-18 19.7 4.0 18.3 3-9 19-2 4.2 17.6 3.9 19-9 3.6 18.8 3-8 19.1 3.7 18.0 4.0 18.0 3-6 18.2 4.1 20-3 3-9 19.0 4.0 21.6 3-2

19-25 19.4 4.2 18.3 4.1 19.1 4.4 17.4 4.1 19-7 3.7 18.6 3-9 18.8 3.8 17.8 4.1 17-8 3-9 18.0 4.2 20.0 4.0 18.8 4.2 21.3 3-3

26-01 18.7 4.2 18.1 4.3 18.9 4.7 17.1 4.2 19-5 4.0 18.2 4.0 18.4 4.2 17.6 4.3 17-6 4.2 18.0 4-5 19-9 4.4 18.7 4.4 21.1 3-5

Apr.02-08 18.3 4.4 17.8 4.6 18.5 4.9 16.7 4.3 19-1 4.1 17-9 4-3 18.0 4.4 17.4 4.4 17.2 4.2 17.8 4.8 19-5 4.5 18.4 4.5 20.8 3-7

09-15 17.8 4.5 17-5 4.8 18.2 5-1 16.4 4.5 18.9 4.3 17-7 4.4 17.7 4.6 17-1 4.5 17.0 4.5 17.7 5-1 19-1 4.7 18.1 4.7 20.4 3-9

16-22 17-5 4.5 17-3 5-0 17.9 5-2 16.0 4-7 18.4 4-5 17.4 4.4 17-3 4.7 16.7 4.7 16.6 4.6 17-6 5-2 18.8 4.9 17-9 4.8 20.1 4.1

23-29 17.4 4.6 16.8 5-1 17.5 5-4 15-5 4-7 18.1 4.7 17.0 4.4 16.9 4.8 16.2 4.6 16.1 4.6 17.4 5.4 18.4 5.0 17.6 4.8 19-7 4.5

30-06 17.4 4.6 16.9 5-2 17-5 5.5 15.5 4.6 18.0 4.7 17.2 4.5 16.9 4.8 16.1 4.8 16.0 4.6 17.1 5.4 17.9 5-2 17.4 4.9 19-2 4.6

May

07-13 17.2 4.5 16.9 5-1 17.5 5.4 15-5 4.5 18.0 4.5 17-2 4.3 16.7 4.7 16.0 4.8 15.8 4.4 16.9 5-3 17-7 5-1 17.2 4.8 18.9 4.5

14-20 17-1 4.4 17.0 5-1 17-5 5-4 15.5 4.4 17-9 4.5 17.0 4.2 16.5 4.5 16.0 4.8 15-7 4.3 16.9 5-2 17.6 5-2 17-3 4.9 18.8 4.6

21-27 17.2 4.3 17.2 4.9 17-8 5-3 15.8 4.3 18.1 4.4 17-3 4.2 16.6 4.4 16.1 4.7 15.9 4.2 17-1 5.1 17.7 5-1 17.4 4.8 18.8 4.6

28-03 17.3 4.2 17-5 4-9 17.8 5-1 16.0 4.2 18.2 4.2 17.4 4.1 16.5 4.1 16.3 4.6 16.0 4.0 17-1 5.0 17.8 5.0 17.4 4.7 18.8 4.3

June

04-10 17.4 4.1 17.4 4.8 17-9 5-0 15.8 4.0 18.2 4.2 17-3 3-9 16.4 4.0 16.5 4.5 16.O 4.0 17.3 4-9 17-9 4.9 17.4 4.6 18.9 4.2

11-17 17.4 4.1 17.5 4.8 18.0 4.9 15-8 3-9 18.2 4.2 17-1 3-8 16.2 3-9 16.7 4.4 16.0 3-8 17.5 4.9 18.1 4.7 17.6 4.6 19.0 4.0

18-24 17.4 4.2 17.6 4.8 18.0 4.9 15-9 4.0 18.1 4.2 17-1 3.8 16.2 4.1 16.9 4.3 16.2 3.8 17.6 4.8 18.2 4.6 17.6 4.5 19-1 4.0

25-01 17.4 4.1 17.7 4.7 18.1 4.8 16.2 4.0 18.0 4.1 17.0 3-7 16.1 4.0 17.2 4.1 16.5 3-8 17.8 4.6 18.4 4.5 17-9 4.5 19-2 3-9

July02-08 17.4 4.1 17.8 4.7 18.3 4.8 16.2 4.0 18.1 4.2 17.1 3-6 16.2 4.0 17.4 4.1 16.5 3-8 18.0 4.6 18.6 4.6 18.1 4.5 19.2 3-7

09-15 17.6 4.2 18.0 4.7 18.4 4.8 16.5 4.1 18.1 4.2 17-1 3-6 16.3 4.0 17.4 4.0 16.6 3-7 18.2 4.6 18.6 4.4 18.2 4.5 19.2 3.8

16-22 17.8 4.1 18.0 4.7 18.5 4.8 16.5 4.0 18.1 4.2 17-1 3-6 16.4 4.0 17-5 3-9 16.7 3-7 18.3 4.6 18.7 4.4 18.2 4.4 19.2 3-7

23-29 18.1 4.2 18.2 4-7 18.7 4.8 16.7 4.0 18.4 4.1 17-3 3.7 16.7 4.0 17.6 3.9 16.7 3-5 18.4 4.5 18.8 4.3 18.4 4.4 19.2 3-6

30-05 18.3 4.1 18.4 4.8 18.9 4.8 16.8 3-9 18.5 4.0 17-4 3-7 16.7 4.0 17.8 4.0 16.7 3.6 18.3 4-5 18.6 4.3 18.2 4.3 19.1 3-6

Aug.06-12 18.4 4.2 18.6 4.7 19.0 4.7 17.0 3-8 18.6 3-9 17-6 3-7 17.0 4.1 18.0 3-9 17.0 3-7 18.4 4.5 18.6 4-3 18.3 4.4 19-0 3-7

13-19 18.5 4.2 18.8 4.6 19-2 4-7 17.2 3-9 18.9 3-9 17.8 3.8 17-3 4.1 18.3 4.0 17-1 3-7 18.6 4.5 18.8 4.4 18.5 4.4 19.2 3-7

20-26 18.6 4.1 19-1 4.6 19-4 4.7 17.6 4.0 19-0 3-9 18.1 3.8 17-5 4.1 18.5 4.0 17.4 3-7 18.8 4.6 19.0 4.4 18.7 4.4 19.4 3-7

27-02 18.7 4.1 19.2 4.6 19-6 4.6 17-7 4.0 19.1 3.8 18.2 3-7 17.6 4.1 18.6 3-9 17.6 3-8 18.8 4.5 19.0 4.5 18.8 4.4 19.4 3-8

Sept.

03-09 18.9 4.1 19.4 4.5 19.8 4.5 17-9 4.0 19.3 3-8 18.5 3.8 18.0 4.1 18.7 4.0 17.8 3-9 19-0 4.5 19.1 4.4 19.0 4.4 19-4 3-610-16 19.1 4.1 19.4 4.4 19-9 4.4 17-9 4.0 19-3 3-8 18.6 3-9 18.1 4.1 18.7 4.0 17.7 3-8 19.0 4-5 19.2 4-5 19-1 4.4 19-5 3.7

17-23 19.0 4.1 19.4 4.4 19.8 4.4 17.9 4.0 19-1 3-8 18.6 3-9 18.1 4.1 18.6 4.1 17-7 3.8 19-1 4.5 19-2 4.5 19.2 4.3 19.4 3.624-30 19.2 4.0 19.3 4.4 19-9 4.4 17-9 4.0 19.2 3-7 18.6 3-9 18.2 4.1 18.7 4.1 17-7 3-8 19.2 4.5 19-3 4-3 19-2 4.2 19-5 3-7

Oct.

01-07 19.3 4.0 19-2 4.3 19-8 4.4 17-9 4.0 19.2 3-7 18.7 4.0 18.3 4.1 18.7 4.0 17-7 3.8 19-3 4.4 19.4 4.3 19.4 4.2 19-7 3-7

08-14 19.3 4.0 19.2 4.4 19-7 4.4 17.9 4.0 19.2 3.8 18.6 3-9 18.4 4.1 18.7 4.0 17-7 3-8 19.4 4.3 19 •£ 4.2 19.5 4.1 19-9 3-5

15-21 19.4 4.0 19.2 4-3 19-6 4.4 18.0 4.0 19.2 3-7- 18.6 4.0 18.5 4.0 18.9 4.1 17-9 3-8 19.6 4.1 19.8 4.1 19.5 4.0 20.1 3-422-28 19.8 3-8 19.4 4.2 19-9 4-3 18.2 4.0 19-5 3-6 18.8 3-9 18.8 3-9 19.O 4.0 18.2 3-8 19.7 4.2 20.0 4.0 19-7 4.0 20.4 3-5

29-04 20.0 3.8 19-5 4.0 20.0 4.1 18.6 4.1 19-7 3-6 19.0 3.8 19.2 3-9 19-3 3-9 18.5 3-8 19.9 3-9 20.3 3-9 19.7 3.8 20.6 3-3

Nov

05-11 20.1 3.6 19.9 4.0 20.3 3-9 18.8 4.0 19-9 3-4 19-2 3-7 19-5 3-7 19-5 3-9 18.9 3-7 20.0 3.8 20.5 3-8 19.8 3.8 20.8 3-2

12-18 20.3 3.4 20.0 3-8 20.6 3.8 19.0 3-8 20.1 3.4 19.4 3-7 19-7 3-5 19.8 3.8 19-2 3.7 20.1 3-8 20.6 3-7 19.8 3-8 20.9 3-2

19-25 20.6 3-3 20.1 3.7 20.9 3-6 19.4 3.8 20.4 3.3 19.7 3-5 20.1 3-4 20.0 3-8 19-5 3-6 20.2 3.8 20.9 3-5 19.9 3.7 21.1 3-0

26-02 20.6 3-4 20.1 3-6 21.2 3-6 19.5 3-6 20.6 3-1 19.8 3-5 20.2 3-3 20.1 3-8 19.7 3-7 20.1 3.8 21.1 3-6 20.0 3-6 21-3 3-1

Dec.

03-09 20.8 3.4 20.1 3-5 21-5 3-5 19.9 3-5 20.8 3-0 19.9 3.4 20.3 3.2 20.3 3.8 19-8 3-5 19.9 3-7 21.1 3-5 20.0 3-5 21.3 2.9

10-16 20.9 3.3 20.1 3-4 21.8 3.4 20.1 3-4 20.9 2.8 20.0 3-3 20.5 3-1 20.5 3-7 20.0 3-5 19-9 3-7 21.5 3-4 20.3 3.4 21.6 2-9

17-23 21.1 3-3 20.2 3-3 22.1 3-3 20.5 3-4 21.3 2.8 20.2 3-3 20.6 3.0 20.6 3.7 20.4 3-5 20.0 3-5 21.8 3.2 20.5 3-2 21.8 2.8

24-30 20.8 3-2 20.1 3.4 21.9 3-2 20.5 3-5 21.2 2.8 20.1 3.3 20.6 5-0 20.5 3-6 20.3 3-5 19-7 3.5 21.8 3-2 20.5 3.1 21.8 2.8

31- 20. 6 3-2 19.8 3-1 21.8 3-2 20-3 3-5 21.2 2.8 20.1 3-3 20.4 2.9 20.4 3-5 20.1 3.4 19.6 3-4 21.8 3-2 20 5 3.1 21 9 2.8

are below those resulting from 24-hoperation throughout the year. In winterthere is a fraction of 1% (WB) difference,rising to almost 2% (WB) during summer.At a temperature of 60°F, according toBloome (1), a 2% lowering from, forexample 22 to 20% (WB), will prolongthe storage life (safe storage) by 10 d,while drying from 20 to 18%(WB) willlengthen it by 40 d.

The change of airmasses occasioned bythe passage of synoptic-scale high and low

pressure systems means an almost interminable alternation of dry and moistperiods for most of Canada, throughoutthe year. Often the temperature does notchange as much as the relative humidityin these cases. This appears to present thepossibility of selective corn drying, usinga device such as a humidistat to operatethe fan motor. This way, surely, theresulting equilibrium moisture contentscould be lowered several points.

The heat given off in cooling the fan

motor can be utilized inside the bin byorienting the air flow into the storage bin;this will raise the inside temperature andlower the relative humidity value accordingly. The result is an equilibriummoisture content 1-2% (WB) lower thanthat resulting from the use of an exhaustsystem, according to Bloom (1).

In addition, the use of bin heatersshould be considered, especially withcorn of high initial moisture content.However, this is bound to add consider-

CANADIAN AGRICULTURAL ENGINEERING, VOL. 16, NO. 2, DECEMBER 1974 100

SMOOTHED WEEKLY MEANS AND STANDARD DEVIATIONS OF EQUILIBRIUM MOISTURE CONTENTIN PERCENT WET BASE OF SHELLED CORN WITH FAN OPERATION FROM 0600 TO 1800 L.S.T.

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Jan.

01-07 21.9 3-0 19-9 3-0 21.1 3-7 19.2 3-6 17-3 4.4 16.7 3-7 22.7 2.8 20.4 2.6 20.6 3-1 21.0 3-0 20.3 3-1 20.1 3.5 21.7 2.8 21.1 2.908-14 21.8 3-3 19.8 3-0 20.7 4.0 19-2 3-5 17.5 4.5 16.7 3-7 22.8 2-9 20.4 2.6 20.6 3.1 20.9 2.9 20.2 3-1 19.9 3-5 21-7 2.8 20.8 3-0

15-21 21.5 3-3 19.7 3.2 20.7 4.0 19-5 3-3 17-8 4.5 16.9 3.7 22.7 3-1 20.5 2.8 20.8 3.0 20.7 2.9 20.2 3-2 19-8 3.6 21.4 2-9 21.1 2-922-28 21.2 3^ 19-7 3.4 20.0 4.1 19.9 3.4 18.0 4.5 17.1 3-7 22.7 3.0 20.6 2.8 20.9 2.9 20. + 2-9 20.1 3-1 19-9 3.6 21.2 3-0 20.9 3-0

29-04 21.1 3.3 19-7 3-5 19-9 4.2 19-9 3-5 18.1 4.5 17-3 3-8 22.7 3.1 20.6 2.8 21.1 2.9 20. 5 3.0 20.2 3.2 20.0 3-5 21.1 3-0 20.6 3-0

Feb.

05-11 20.8 3.4 19-5 3-7 19-7 4.3 19.7 3.6 18.1 *.5 17.1 3-8 22.4 3.0 20.4 2.8 20.8 2.9 19.9 3-0 19-9 3-2 20.1 3.5 21.0 3-0 20.4 3.0

12-18 20.3 3-5 18.7 3-8 19-3 4.3 19-3 3-5 17-7 4.5 17-1 4.1 21.9 2.9 20-3 2.9 20.6 3.0 19-5 3-0 19.8 3-1 19-9 3.4 20.8 3-2 20.1 3-1

19-25 19.9 3-6 18.1 4.0 19.0 4.4 19-0 3-5 17.6 4.4 17.0 4.0 21.8 2.9 20.2 2.9 20.4 3.0 19. + 3-2 19-7 3-0 19.9 3-6 20.6 3-2 19-6 3-2

26-04 19-6 3-7 17.2 4.2 18.6 4.5 18.6 3-5 17.4 4.5 16.7 4.1 21.4 3-0 20.0 3.0 20.0 3-3 19.1 3-3 19.5 3.1 19.5 3-7 20.3 3-4 19.8 3-3

Mar.

05-11 19.0 3-8 16.3 4.3 17.9 4.6 18. 5 3.6 17.0 4.5 16.3 4.3 21.1 3-1 19.8 3.1 19-7 3-7 18.7 3-2 19.2 3-0 19-3 4.0 19.9 3-5 19.8 3-512-18 18.7 3.6 15.8 4.2 17.6 4.4 18.0 3-8 16.7 4.7 16.0 4.6 20.4 3-3 19-4 3.2 19.2 4.0 18. 5 3-4 19-2 3-3 18.9 4.2 19-5 3-9 19.9 4.1

19-25 18.5 3-5 15-4 4.2 17.4 4.4 17.7 4.0 16.5 5-0 15.6 4.8 19.8 3-7 18.8 3.4 18.6 4.4 18.2 3.5 18.9 3-5 18.4 4.2 19.0 4.0 19.3 3-7

26-01 18.2 3-4 14.8 4.1 17-3 4.3 16.9 4.3 16.0 5-3 15.1 5-2 18.7 4.1 17.9 3-7 17.6 5-0 17.7 3.6 18.2 3-7 17.6 4.4 18.3 4.4 18.6 4.1

Apr.02-08 17.8 3-3 14.3 3.8 17.0 4.2 16.2 4.4 15.6 5-4 14.7 5.2 17.5 4-5 16.9 4.0 16.7 4.8 17.3 3.7 17-5 3-9 17.2 4.5 17-9 4.6 18.0 4.309-15 17-6 3-2 14.0 3.8 16.9 4.0 15.3 4.6 15.2 5.4 14-5 5.2 16.5 4.8 16.0 h.3 16.0 5-0 17. L 4.0 17.1 4.2 16.9 4.6 17.4 4.7 17.4 4.516-22 17.3 3-2 13.6 3.7 16-7 3-8 14.7 4.7 14.9 5-5 14.2 5.3 15-7 5-1 15.0 4.5 15-5 5-3 16. 5 4.1 16.3 4.3 16.5 4.6 16.9 4.7 17.0 4.723-29 17.1 3-2 13-4 3.6 16.7 3.8 14..L 4.6 14.7 5-4 14.1 5.3 15.0 5-2 14.2 4.4 15.O 5.4 16.0 4.3 15.6 4.4 16.2 4.5 16.5 4.8 16.6 4.8

30-06 16.8 3.2 13-2 3-6 16.3 3.7 13.6 4.5 14.3 5-4 13.8 5-1 14.4 5-1 13.7 4.4 14.5 5-2 15-7 4.7 15-1 4.6 16.1 4.5 16.2 4.6 16.5 4.7

May

07-13 16.7 3-1 13.2 3-7 16.3 3.7 13-3 4.5 13.8 5-2 13.6 5-1 13-9 5.1 13.2 4.4 14.2 5.2 15- 5 4.9 14.7 4.9 15.8 4.3 16.0 4.5 16.3 4.6

14-20 16.5 3.0 13.O 3-4 16.3 3-6 13-3 4.5 13.5 5-0 13.O 4.7 13.5 5.0 12.8 4.4 13-6 5-1 15- D 4.8 14.4 4.9 15-5 4.1 15.8 4-3 16.1 4.321-27 16.5 2-9 13.O 3-3 16.3 3-6 13.3 4.3 13-2 4.9 12.8 4.6 13.4 5.0 12.9 4.6 13.4 5-0 15. 3 4.7 14.3 4.8 15-5 4.0 15.8 4.1 16.0 4.1

28-03 16.5 2.9 13.0 3-3 16.2 3-5 13. + 4.1 13-2 4.7 12.8 4.5 13-5 4.7 13.0 4.5 13-4 4.8 15- 3 4.5 14.3 4.7 15-5 3.9 15.8 4.0 16.2 4.0

June

04-10 16.5 2.9 12.6 2.9 16.2 3.4 13-6 3-9 13.4 4.6 13.O 4.4 13-9 4.7 13.1 4.5 13-9 5-1 15- D 4.2 14.5 4.5 15.4 3.7 15-7 3-8 16.2 3-9

11-17 16.5 2.9 12.6 3.0 16.1 3-3 14. L 4.1 13-9 4.6 13.0 4.3 14.1 4.6 13.4 4.5 13-9 4.8 15- 5 4.1 14.7 4-3 15-3 3-7 15-5 3-7 16.3 3-9

18-24 16.6 2.9 12.6 3-0 16.0 3-3 14. L 3.9 13-9 4.6 13-1 4.3 14.2 4.4 13.4 4.2 14.0 4.6 15.3 4.0 14.7 4.2 15-3 3.6 15-5 3-8 16.3 3.825-01 16.5 2.8 12.3 3-0 15.9 3-4 14.2 3.8 13.9 4.4 13.O 4.2 14.2 4.3 13.4 4.0 13.9 4.4 15- 2 3-7 14.9 4.0 15.3 3-6 15.4 3.7 16.3 3.9

July02-08 16.5 2.8 12.0 2-7 15.8 3-3 14.3 3-8 13-7 4.2 12.6 3.8 13.9 4.1 13.4 3.9 13.6 4.2 15- 3 3-5 15.0 3-8 15-3 3.6 15.3 3-7 16.2 3.9

09-15 16.7 2.8 12.0 2.7 15.8 3.4 14. 5 3-6 13-7 4.1 12.4 3.8 13.7 4.0 13.4 3-7 13-2 3-9 15-5 3-5 15.O 5-7 15-4 3-6 15.4 3-8 16.2 3-9

16-22 16.7 2.8 12.0 2.8 15.8 3-6 14. 5 3-5 13.6 4.1 12.2 3.6 13.5 4.0 13.3 3-7 12.9 3-9 15. 3 3-3 15-0 3-7 15-6 3.6 15-5 3-8 16.3 3-9

23-29 16.7 2.8 12.0 2.7 15-7 3-7 14.7 3-7 13.6 3-9 12.1 3.6 13.4 4.1 13-3 3-9 12.7 3-9 15. 4 3-4 15.0 3-7 15.8 3-6 15.8 3.8 16.5 3-9

30-05 16.9 2.8 12.2 2.9 15-8 3-7 14.8 3.8 13.6 4.1 12.1 3-8 13.2 4.2 13.3 4.0 12.6 4.0 15-5 3-6 14.9 3.7 15.8 3-4 16.0 3.8 16.7 4.0

Aug.06-12 17.1 2.9 12.4 2.8 16.0 3-7 15- D 4.0 13.8 4.3 12.4 4.2 13.2 4.4 13-3 4.0 12.7 4.2 15- 5 3.6 15.0 4.0 16.2 3.7 16.2 3-8 16.8 3-9

13-19 17-3 3.0 12.7 2.9 16.4 3-8 15- 1* 4.1 13-9 4.2 12.6 4.2 13.6 4.6 13.8 4.4 13.2 4.5 15.9 3-8 15.3 4.1 16.5 3-7 16.6 3-9 16.9 4.0

20-26 17.4 2.9 12.9 3.0 16.5 4.1 15-6 4.2 14.0 4.3 12.8 4.3 13.8 4.6 14.1 4-5 13.4 4.7 16. 2 3.8 15-5 4.2 l£.6 3-6 16.7 4.0 17.1 4.0

27-02 17.8 3.0 13-2 3.1 16.8 4.1 15- 3 4.3 14.5 4.7 13.3 4.6 14.1 4.7 14-5 4.6 13.9 4.9 16. 3 3-9 15.8 4.3 16.7 3-7 16.7 4.0 17.2 4.1

Sept.

03-09 18.2 3-1 13.6 3.3 17.2 4.2 16.0 4.4 14.7 4.8 13.8 4.8 14.5 4.8 14.7 4.6 14.4 5.1 16.6 4.0 15-9 4.3 17.0 3-7 17.0 4.0 17.4 4.0

10-16 18.5 3.0 i4.o 3-3 17.6 4.2 l£.o 4.3 14.7 4.8 13-9 4.8 15.0 4.8 15.O 4.6 14.7 5-1 16.7 4.1 16.0 4-3 16.9 3-6 17.0 4.0 17.8 4.1

17-23 18.8 3.1 14.3 3-4 17.7 4.3 15- 3 4.4 14.6 4.9 13.9 5-1 15-1 4.9 15.0 4.5 14-7 5-1 16.6 4.0 15.8 4.3 16.8 3-8 17.0 4.0 18.0 4.0

24-30 19-3 3.1 15.0 3-6 18.2 4.2 16. 0 4.6 14.8 5-0 14.2 5.0 15.5 5.0 15-3 4.5 15.0 5.0 16.8 4.2 16.0 4.4 16.9 3-9 17.2 4.0 18.2 3-9

Oct.

01-07 19.8 3-1 15-5 3-7 18.6 4.1 15- B 4.5 14.5 4.9 14.2 5.0 15.7 5-1 15.3 4.5 15.1 4.9 17. 0 4.4 16.0 4.5 17.0 4.0 17-4 4.1 18.5 4.0

08-14 20.2 3-1 16.1 3-7 18.9 4.0 15- B 4.5 14.6 5-1 14.2 4.9 16.0 5-0 15-7 4.6 15.4 5-1 17- 2 4.2 16.2 4.4 16.9 4.0 17.6 4.2 18.7 3-3

15-21 20-5 3-1 16.5 3-9 19-2 4.0 15-9 4.5 14.7 5-0 14.2 4.9 16.2 4.9 16.1 4.4 15.8 5-0 17- 5 4.2 16-5 4.5 17-1 4.1 17-8 4.2 18.7 3-3

22-28 20.8 3.1 17.1 3-9 19.5 4.0 16. 2 4.3 15.3 5-1 14.7 4.7 16.7 4.7 16.7 4-3 16.4 4.8 18. 0 4.1 16.9 4.3 17.6 4.2 18.4 4.1 19.4 3.8

29-04 20.9 3-2 17.5 3-9 19-7 3.9 17- 0 4.2 16.0 5-0 15.5 4.8 17.7 4.4 17.8 4.2 17-4 4.8 18. 5 3.8 17.4 4.0 18.1 4.2 18.9 3.9 19.8 3-7

Nov.

05-11 20.9 3-1 18.1 3.7 19-9 3-9 17.9 4.1 16.7 4.8 16.1 4.5 18.9 4.2 18.9 3-9 18.5 4.5 19. 2 3-5 18.1 3-7 18.4 4.0 19-3 3.8 20.4 3.3

12-18 21.0 3-1 18.4 3-7 20.0 3.8 18. 3 3.8 17-1 4.6 16.3 4.3 19-7 3.8 19-5 3-5 19.2 4.2 19- 4 3-4 18.8 3-5 18.7 4.0 19-5 3-5 20.7 3.3

19-25 21.2 3.0 18.9 3-5 20.3 3-7 18.7 3-7 17-6 4.5 16.8 4.2 20.4 3-5 20.3 3-3 19.6 4.2 20. 3 3-2 19.4 3-3 19.2 3-9 20.1 3.5 21.0 3-2

26-02 21.4 3.0 19.2 3-3 20.6 3-7 19. 0 3.5 17-7 4.4 17.0 4.0 21.3 3-3 20.8 3-0 20.0 3-7 20. 8 3-1 20.0 3.2 19.5 3-7 20.4 3-3 21.3 3-0

Dec.

03-09 21.8 3-0 19-6 3-2 20.8 3.5 18.9 3.4 17.4 4.3 16.9 3-7 21.7 3-1 20.9 2.9 20.1 3.4 20.9 3-0 20.2 3-1 19-9 3-7 20.7 3-2 21-5 3-1

10-16 22.0 2.8 19-9 3-2 21.1 3-4 19- 0 3-4 17.2 4.1 16.7 3-5 21.9 2.8 20.9 2.7 20.2 3.3 21. 3 3-0 20.4 3.0 20.3 3-6 21.1 3-1 21.5 3.0

17-2324-30

22.1 2.8 20.0 2-9 21-3 3-5 19. 1 3-6 17.2 4.2 16.8 3-7 22.4 2.7 20.9 2.6 20.4 3-3 21. 5 2.9 20.4 2-9 20.7 3-5 21.7 2-9 21-5 2.9

22.2 2.8 20.2 2-9 21.4 3.4 19. 1 3-6 17-1 4.2 16.7 3-7 22.6 2.8 20.8 2.7 20.4 3-3 21. 3 2.9 20.4 3.0 20.6 3-4 21.8 2.8 21.3 2.9

31- 22.0 2.8 20.1 2.8 21.4 3.4 19- 2 3-6 17.3 4.3 l£.7 3-7 22.6 2.9 20.5 2.7 20.5 3-1 21.3 2.9 20-3 3.0 20. 3 3-5 21.8 2.8 21.2 2.9

ably to the cost, which will varyaccording to the fuel used and the region.

SUMMARY

A formula developed by Henderson(5) for the equilibrium moisture contentof kernel corn resulting from exposure toambient air, and another one by Sabbah(4), for high relative humidity values, wasused to derive weekly mean values of

101

equilibrium moisture content and theirstandard deviations for a number ofstations across Canada. The resultingseasonal and regional variations werediscussed. The results suggest that selective fan operation could bring about asignificant lowering of the equilibriummoisture content. The addition of asensing device like a humidistat toexisting air drying systems could effect afurther improvement in the dryingpotential of the ambient air.

REFERENCES

Bloome, P.D., 1969. Use of weather datato predict the performance of natural airdrying systems. Unpublished Paper. Dep.Agric. Eng., University of Illinois. 1969.

Shove, G.C. 1971. Low temperaturedrying of shelled corn. Agric. Eng. 52:372-373.

Shove, G.C. 1971. Drying shelled cornwith electric heat. HL Res. 13: 8-9.

CANADIAN AGRICULTURAL ENGINEERING, VOL. 16, NO. 2, DECEMBER 1974

TABLE II (CONT'D) SMOOTHED WEEKLY MEANS AND STANDARD DEVIATIONS OF EQUILIBRIUM MOISTURE CONTENTIN PERCENT WET BASE OF SHELLED CORN WITH FAN OPERATION FROM 0600 TO 1800 L.S.T.

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Weeks Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D Me S.D

Jan.

01-07 20.1 3-3 19.0 3-2 20.8 3-2 19.5 3-5 20.9 2.8 19.4 3-2 19-9 3-0 19-7 3-5 19-4 3-4 19-1 3-6 21-3 3.4 20.3 3-2 21.6 2.9

08-14 20.1 3-4 18.9 3-3 20.7 3-3 19-4 3-6 20.9 2-7 19.2 3-3 19.7 3.0 19-5 3.5 19-5 3.5 18.9 3-7 21.0 3.4 20.2 3-3 21-5 3-1

15-21 19-9 3-4 18.7 3-3 20.4 3-5 19.2 3.6 20.9 2-9 18.7 3-3 19-6 2.9 19-4 3-4 19.3 3-5 18.5 3.8 20.8 3-7 19.9 3-5 21-3 3-2

22-28 19-7 3-5 18.6 3-3 20.1 3-7 18.9 3-6 20.8 3.0 18.6 3-3 19-5 3.4 19.2 3-4 19.2 3-5 18.5 3.8 20.6 3-7 19.9 3-5 21.3 3-3

29-04 19.6 3-5 18.6 3-5 20.0 3.8 19.1 3.8 20.6 3.0 18.8 3-3 19.3 3-2 19-1 3.5 19.4 3-7 18.4 3-9 20.4 3-7 19.7 3.5 21.2 3-3

Feb.

05-11 19-4 3-5 18.5 3-5 19.9 3-9 18.9 3-9 20.4 3-0 18.8 3-3 19-3 3-2 18.8 3-5 19.3 3-7 18.3 3.8 20.2 3.7 19.6 3-6 21.1 3.3

12-18 19.2 3.6 18.3 3-6 19.6 4.1 18.6 3.9 20.1 3.1 18.8 3-5 19.2 3-3 18.8 3-7 19.0 3-7 18.2 3-8 20.1 3-7 19.5 3-7 21.2 3-2

19-25 19.0 3-7 18.0 3.5 19-1 4.1 18.6 3-8 19-9 3.2 18.8 3-6 19.1 3-4 18.4 3-7 18.6 3.7 18.0 3.7 20.0 3-8 19.2 3-7 21.4 3-2

26-04 18.9 3.9 17-9 3-6 18.9 4.1 17.9 4.0 19-7 3-3 18.7 3-7 19.0 3-5 18.1 3.8 18.2 3.7 17.8 3-9 19.8 3.9 18.8 3-8 21.3 3.2

Mar.

05-11 19.0 4.0 17.6 3.7 18.5 4.2 17.4 3-8 19-5 3.4 18.4 4.2 18.7 3-7 17.8 3-9 17.8 3.7 17.6 3-8 19-8 4.0 18.6 3-9 21.3 3.3

12-18 18.7 4.2 17.2 3-9 17.9 4.3 17.1 3-9 19.2 3-6 18.0 3-8 18.2 3-8 17-4 4.1 17.2 3-8 17-3 4.0 19-5 4.0 18.0 4.0 21.1 3.3

19-25 18.2 4-3 17.0 4.0 17-7 4.4 16.7 4.0 19.0 3-7 17.4 4.0 17-9 4.0 17.0 4.1 17.0 3-9 17.0 4.4 19.2 4.3 17-7 4-3 20-8 3.4

26-01 17.4 4.3 16.7 4.3 17.3 4.7 16.3 4.3 18.6 4.0 17.1 4.0 17-3 4.3 16.7 4.3 16.7 4.2 16.9 4.6 18.9 4.5 17-5 4.6 20.5 3.8

Apr.02-08 17.1 4.5 16.1 4.5 16.7 4.9 15.7 4.3 18.1 4.2 16.6 4.2 16.7 4.5 16.2 4.4 16.1 4.2 16.5 4.9 18.4 4.8 16.9 4.7 20.0 4.0

09-15 16.4 4.6 15-7 4.7 16.3 5-0 15-3 4.5 17-8 4.5 16.3 4-3 16.1 4.7 16.0 4.5 15-9 4.6 16.2 5-2 17-7 5-0 16.5 4.8 19.4 4.2

16-22 16.0 4.6 15.3 4.2 15-9 5-3 14.8 4.6 17.2 4.6 16.0 4.4 15.8 4.8 15-5 4.8 15.4 4.6 16.0 5-5 17.2 5-1 16.2 4.9 18.9 4.4

23-29 16.0 4.7 14.6 4.1 15.4 5-3 14.2 4.6 16.8 4.8 15.6 4.3 15.4 4.9 14.8 4-7 14.9 4.5 15-7 5.5 16.7 5-2 15.8 4.9 18.4 4.730-06 16.0 4.6 14.5 4.8 15.3 5-4 14.2 4-5 16.7 4.7 15.7 4.3 15-3 4.8 14.7 4.9 14.7 4.5 15.3 5.5 16.0 5.2 15-5 5-0 17-7 4-7

May

07-13 15.6 4.3 14.6 4.8 15-1 5-2 14.2 4.4 16.6 4.6 15.6 4.2 15-0 4.6 14-5 4.9 14.6 4.4 15-1 5.3 15.8 5-2 15-3 4.8 17.4 4.714-20 15.5 4.2 14.5 4.6 15.O 5.0 14.0 4.2 16.5 4.5 15.5 4.1 14.8 4.3 14.4 4.8 14.4 4.2 15.2 5-3 15.8 5-2 15.4 4.9 17-3 4-721-27 15-5 4.0 14.7 4.2 15-2 4.8 14.2 4.0 16.5 4.2 15-7 4.0 14.8 4.2 14.5 4-7 14-5 4.0 15.4 5-2 15.8 5-0 15-5 4.8 17.4 4.8

28-03 15-5 3-8 14.9 4.2 15.2 4.6 14.5 4.0 16.6 4.1 15.8 3-8 14.7 3.9 14.6 4.6 14.7 3-9 15-3 5-0 15.8 4.8 15-4 4.6 17.4 4.4

June

04-10 15-5 3-7 14.7 3-9 15.2 4.3 14.3 3-8 16.5 4.1 15-6 3-6 14.6 3.7 14.7 4.4 14.5 3-6 15-5 5.0 16.0 4.8 15.4 4.4 17.4 4.2

11-17 15.5 3-7 14.7 3-7 15.3 4.3 14.3 3-8 16.4 4.0 15-5 3-5 14.5 3-7 14.9 4.4 14.7 3-7 15.7 4.8 16.2 4.5 15.5 4.3 17.6 4.0

18-24 15-4 3-7 14.8 3.8 15.3 4.3 14.4 3-8 16.2 3.9 15-4 3-4 14.4 3-6 15.1 4.2 14.8 3-7 15-8 4.8 16.5 4.6 15.6 4.3 17-8 4.0

25-01 15.4 3-7 14.9 3-8 15.4 4.1 14.5 3-7 16.2 3.9 15-3 3-3 14.3 3-7 15-4 4.1 15.0 3.6 16.0 4.7 16.6 4.5 15-8 4.3 17-8 3.9

July02-08 15-3 3-6 15.0 3.8 15.5 4.2 14.5 3-6 16.2 3-9 15.3 3-1 14.3 3.5 15-5 3-9 15-0 3.5 16.2 4.6 16.7 4.4 16.0 4.3 17.8 3.7

09-15 15-5 3-7 15-1 3-8 15.5 4.1 14.7 3-7 16.1 3-8 15-4 3-2 14.4 3-6 15-6 3-8 15-2 3-5 16.3 4.6 16.8 4.3 16.0 4.3 17-8 3.7

16-22 15-7 3-8 15.2 3-9 15.5 4.0 14.8 3.6 16.1 3-7 15.4 3.2 14.5 3-7 15-6 3-7 15-2 3.4 16.4 4.7 16.8 4.3 16.1 4.3 17.8 3-6

23-29 15-9 3-8 15.3 3-7 15.8 4.1 15.0 3-6 16.3 3-7 15-5 3.1 14.7 3-7 15.8 3-8 15-3 3-3 16.5 4.6 16.8 4.2 16.1 4.2 17.7 3-6

30-05 16.1 3-7 15-5 4.0 15.9 4.1 14.8 3-5 16.6 3.7 15-6 3.2 14.7 3.6 15-9 3-9 15-2 3-3 16.4 4.6 16.8 4.4 16.0 4.1 17.5 3-6

Aug.06-12 16.2 3-8 15.8 4.1 16.0 4.1 15-4 3-7 16.7 3-7 15-8 3.4 15.0 3-8 16.2 3-9 15-5 3-5 16.5 4.6 16.7 4.3 16.1 4.3 17.4 3.7

13-19 16.2 3.8 16.0 4.1 16.4 4.2 15.6 3.8 17.0 3-7 16.0 3.5 15-3 3.7 16.5 4.1 15.6 3.6 16.7 4.7 16.9 4.5 16.4 4.4 17.6 3.820-26 16.4 3-9 16.3 4.1 16.6 4.3 15.9 3-7 17.2 3.8 16.2 3.5 15.3 3-8 16.7 4.2 15.8 3-6 16.9 4.9 17-1 4.5 16.6 4.6 17.8 3-9

27-02 16.5 3-9 16.5 4.2 16.9 4.4 16.1 3.9 17.3 3-7 16.3 3.5 15.5 3-8 16.7 4.1 16.0 3-7 16.9 4.9 17-1 4.6 16.7 4.6 17.8 3.9

Sept.

03-09 16.7 4.1 16.8 4.2 17.2 4.3 16.3 3.9 17.6 3-7 16.6 3.6 16.0 4.0 16.9 4.2 16.2 3-8 17.O 4.9 17.2 4-5 16.9 4.5 17-9 3.9

10-16 17.0 4.0 16.9 4.2 17.4 4.3 16.3 3-9 17.6 3-7 16.7 3.7 16.2 4.0 16.9 4.2 16.2 3-7 17.1 4.9 17.2 4.6 16.9 4.5 18.0 3-9

17-23 17.2 4.0 17.0 4.3 17-5 4.4 16.4 4.0 17-6 3-7 16.7 3.7 16.2 4.0 16.9 4.2 16.2 3-7 17-1 4.8 17-3 4.7 17-1 4.5 18.0 3-824-30 17.3 4.0 17-1 4.2 17.6 4.3 16.5 4.0 17.9 3.7 16.9 3.8 16.5 4.1 17.1 4.2 15.3 3-7 17.3 4.8 17-6 4.6 17.4 4.4 18.2 3.7

Oct.

01-07 17.6 4.1 17.2 4.4 17-7 4.4 16.6 4.1 18.0 3-7 17.0 3.8 16.6 4.1 17.3 4.3 16.4 3-8 17-5 4.8 17.8 4.6 17.6 4.4 18.4 3-808-14 17.6 4.1 17.3 4.5 17-7 4.5 16.7 4.2 18.0 3.8 17-1 3.8 16.7 4.2 17.4 4.3 16.5 3.8 17-8 4.8 18.1 4.5 17.9 4.5 18.8 3-815-21 17.8 4.0 17.6 4-5 17.8 4.5 17.0 4.2 18.2 3-7 17.1 3.8 16.9 4.0 17.8 4.4 16.9 3-9 18.1 4.5 18.4 4-5 18.1 4-3 19.2 3.722-28 18.5 4.0 18.0 4.4 18.3 4.4 17-1 4.2 18.7 3-7 17.4 3.8 17-4 4.1 18.0 4.2 17-3 3-9 18.4 4.5 18.8 4.3 18.4 4.2 19-5 3-629-04 18.8 3-9 18.4 4.3 18.8 4.3 17.7 4.3 19.0 4.0 17.8 3.8 17.9 4.0 18.4 4.1 17-8 3.9 18.8 4.3 19-3 4.3 18.6 4.1 19.8 3.6

Nov.

05-11 19.2 3-7 18.8 4.2 19.2 4.1 18.1 4.2 19-4 3-6 18.2 3.8 18.4 3-8 18.8 4.1 18.3 3-9 19.0 4.2 19.6 4.1 18.9 3-9 20.1 3.412-18 19-5 3.6 19.2 4.0 19.6 4.0 18.4 4.1 19-5 3.4 18.5 3.7 18.7 3-6 19.2 4.2 18.6 3.8 19-3 4.2 19-9 4.0 19.0 3-9 20.4 3-6

19-25 19.9 3-4 19.4 3-9 20.1 3.9 18.8 3-9 19.9 3-3 19.O 3.6 19.2 3.4 19-4 4.0 19.0 3-7 19.4 4.0 20.3 3-8 19-3 3-8 20.6 3-326-02 20.0 3-5 19.4 3-7 20.3 3-8 18.9 3-7 20.1 3-2 19-1 3.5 19-1 3-5 19.7 4.0 19.2 3-7 19.4 4.0 20.5 3-8 19-4 3-8 20.9 3.2

Dec.

03-09 20.2 3-5 19.4 3.6 20.6 3-7 19.3 3-7 20.4 3.0 19-2 3.4 19.6 3.4 19-8 3-8 19-4 3-6 19-1 3-8 20.5 5-6 19-5 3-5 21.0 3.0

10-16 20.4 3-5 19-5 3-5 20-9 3-7 19-5 3-5 20.7 2.9 19.5 3.4 19-9 3-3 20.0 3-7 19-5 3-6 19-3 3.8 20.9 3-4 19-9 3-5 21.3 2.9

17-23 20.6 3.4 19-5 3.4 21.3 3-4 19-9 3-5 21.0 2.8 19.8 3.3 20.2 3-3 20.2 3-7 19.9 3-5 19.4 3-6 21.3 3-3 20.3 3.4 21.5 2.8

24-30 20.4 3-4 19.4 3.4 21.2 3-3 19.9 3-6 20.9 2.7 19.6 3.3 20.1 3-1 20.0 3-6 19.7 3-5 19-2 3.7 21.3 3-3 20.3 3.2 21.6 2.8

31- 20 3 3-4 19-2 3-2 21.1 3.3 19.7 3.5 20.9 2.7 19-5 3.2 20.0 3-1 19-9 3-5 19.6 3.4 19 l 3.6 21.3 3-3 20 •3 3-2 21 .6 2.8

Sabbah, M.A. 1968. Prediction of batchdrying performance with natural air.Unpublished M.S. Thesis, Dep. Agric.Eng., Purdue University, January, 1968.

Henderson, S.M. and R.L. Perry. 1955.Agricultural process engineering. JohnWiley and Sons, Inc. New York, N.Y.1955.

CANADIAN AGRICULTURAL ENGINEERING, VOL. 16, NO. 2, DECEMBER 1974 102