Jounal of Agicultual Technology 2009, V.5(1): 17-31 Some physical and mechanical popeties of date palm tees elated to cultual opeations industy mechanization M. Shamsi and S.M. Mazloumzadeh Depatment of Agicultual Machiney, Shahid Bahona Univesity of Keman, keman, Ian. Shamsi, M. and Mazloumzadeh, S.M. (2009). Some physical and mechanical popeties of date palm tees elated to cultual opeations industy mechanization. Jounal of Agicultual Technology 5(1): 17-31. This study was conducted to find some impotant physical and mechanical popeties of date palm tees to be applicable in mechanization of date palm cultual opeations industy. To detemine the tee tunk mechanical popeties as tensile, compessive and shea stength, 9 tee tunk samples wee selected at andom fom diffeent locations within the living tunks and tested by appopiate equipments. Two special tools which had been designed and constucted in Silsoe College wee used fo tests on the cut tunks and on the leaf bases of living tees. The tee tunks aveage stengths esults showed that the longitudinal tensile stength and longitudinal compessive stength ae 60 and 5.34 MPa espectively. It was also indicated that the adial compessive stength is 2.96 MPa and longitudinal shea stength is 1.10 MPa. The expeiment was caied out on the tee tunk leaf bases. It showed that the tee leaf base adial compessive stength is 6.38 MPa and the longitudinal leaf base shea stength is 1.00 MPa. The esults showed that the safety facto of stesses exeted to the tee by a woke o a light tee climbing machine that climb a healthy poducing date tee vay fom 7 to 198 which ae fa fom 1, the citical value. The esults of tee tunk stengths can be used to educe the human, tee and machine damages in the date palm cultual opeations. These can help to design safe tee shakes and othe date palm mechanization machiney by identification of stess limits and safety factos of diffeent stesses exeted to the tee by human o diffeent machines. Results showed that thee wee significant diffeences in impotant physical popeties in tee height, spacing, yield and cicumfeence between main cultivation aeas aound the wold. Results can be used fo detemining acceptable ange of sizes and values of featues fo a new technically acceptable date palm sevice machine. Key wods: date palm tee, physical and mechanical popeties, date palm mechanization, cultual opeations, tee and human safety Intoduction The date palm (Phoenix dactylifea L.) is a mono cotyledon of the family of the Palmate. It is a feathe palm, chaacteized by compound leaves with a seies of leaflets on each side of a common petiole, oiginating fom one Coesponding autho: Mazloumzadeh, S. M.; e-mail: mazloumzadeh@gmail.com 17
gowing point at the top of the tunk. The date palm may each an age of ove 100 yeas and each up to 24 m in height to the gowing point nomally the age limit is less than this and consequently the height will not be moe than 15-20 m maximum befoe it was cut down due to declining yield and the inceasing difficulty (and dange) of eaching the cown duing pollination, bunch management and havesting (Seelig, 1974). The most popula date palm cultual opeations caied out in ochads ae the following: pollination, dehoning, puning, fuit thinning, bending and bagging of bunches and pesticide contol. Bown (1983) showed that among cultual opeations, havesting, pollination and puning ae the most labo intensive wok accounting fo moe than 80 pecent of the total poduction costs. Thee ae two methods of date palm cultual opeations, taditional and mechanical. The most difficult pat of the date palm cultual opeations is eaching the woke to the cown of the tee. It is because the tees ae too tall and the woke is at the isk of falling out off the tee. Using the tee tunk leaf bases to climb the tee in Ian, Iaq and Libya is a taditional way of cultual opeations (Nixon, 1969). Al- Kiady (2000) epoted that the skilled and specialized labos wee becoming ae and expensive causing a seious depession in date poduction industy. Mechanized cultivation methods can impove the date quality and mechanization of date palm cultual opeation is essential to optimize this industy (Albozaha, 2003). Thee is a majo inteest in the mechanization of date cultual opeations, because most of them ae hazadous, time consuming and equie skilled labo in Middle East, the oigin of this fuit (Ismail & Al-Gaadi, 2006; Mazloumzadeh et al., 2008). Enough and compehensive infomation about date palm chaacteistics such as physical and mechanical popeties will enhance the mechanization in this secto. In most of the mechanized cultual opeations, especially in the following studies that a machine moves on the tee tunk, the tee toleates some stesses. To guaantee the tee, the machine and the woke safety it is impotant to know the date palm tee mechanical popeties and the stesses these machines impose on the tee. Davis (1977) developed a coconut tee climbing bicycle, it consisted of an angle-ion famewok with wooden platfom on which the opeato ides. Fiction olles ae passed against the tunk of the palm by the opeato's weight and he is caied to the top as he tuns the handle by hand. Abdalla et al. (1986) developed a simple walk-up elevato to suit date cultual opeations. The elevato was designed whee a woke can lift himself up by pedaling. Saing et al. (1989) in Isael developed an integated mechanical system that could havest the fuits by shaking the tee tunk. Shamsi (1990) designed a spocket type climbing machine to havest dates. The opeato sits on a fame and holds on to a handle. He then dives the climbe by pushing the pedals with his feet. Nicklin (1993) designed a tee climbing test ig to lift a man up to the date palm 18
Jounal of Agicultual Technology 2009, V.5(1): 17-31 tees. Shamsi (1998) designed and developed a tee climbing date havesting test ig in Silsoe College*. This machine climbed up the tee tunk to each the fuit bunches. Many studies have been epoted on the physical popeties of date palm tees, but no detailed study concening mechanical popeties of tee tunks have been pefomed. Pekins and Bown (1964) used a havesting system which thee men including a tuck dive, a boom opeato and a bunch cutte o shake opeate it. Al-Suhaibani et al. (1988) made a date sevice machine in Saudi Aabia which was designed at Silsoe College. They caied out a suvey on 19 ochads in Saudi Aabia and measued some physical popeties as tee spacing, tee height, tunk cicumfeence, bunch spacing and gound pofile. Ahmed et al. (1992) obtained some date palm physical popeties to be applicable in date palm mechanization. They obtained tee featues as age, height, tunk cicumfeence, spacing and cutting esistance of the leaves. Abounajmi (2004) focused on the development of date fuit havesting mechanization. He discusses the stategies fo impoving new method fo date palm cultual opeation, and factos affecting on it. Fadel (2004) designed a date palm sevice platfom based on some date palm physical popeties. Fadel (2005) also designed and developed a tactomounted date palm tee sevice machine. The machine had the capability to lift a woke and the equied tools to the cown zone as high as 4.5m. Mazloumzadeh and Shamsi (2007) evaluated altenative date havesting methods in Ian using some physical popeties of date palm tees. They showed that any new haveste machine must be able to each the lifting height of 10 m. it must be able to cay a maximum payload of aound 1100-1300 N and have a length less than 3 m. Shamsi et al. (2005) found some physical popeties as date palm visual appeaance, yield, fuit quality, tee age and numbe of bunches to be applicable in pecision agicultue. Mazloumzadeh et al. (2007) designed and developed a light tacto-mounted date palm sevice machine. Machine could each to a maximum woking height of 10 m with maximum payload of 130 kg. Mazloumzadeh et al. (2008) developed a fuzzy decision making technique to classify available geneal-pupose liftes in Ian fo the date havesting industy based on some physical popeties of date palm tees. Mateials and methods The date palm physical and mechanical popeties study was caied out in Bam and Shahdad, two main date poduce aeas in Ian which is the second wold poduce. The failue stess tests wee conducted on newly cut tee tunks. The tunk was cut into the small samples which wee tested by * Canfield Univesity, Silsoe, Bedfod, United Kingdom. 19
equipment in the mateial physical testing laboatoy of Keman Univesity. Two special tools which had been designed and constucted in Silsoe College wee used fo tests on the cut tee and on the leaf bases of living tees. Physical paametes including tee tunk height, tee cicumfeence at gound and cown, bunch and stalk weight, numbe of bunches, leaf base pitch, leaf base height, yield and tee spacing including inte ow spacing, inta ow spacing and distance to neaest tee wee measued using diffeent equipments. 25 andom tees in 9 diffeent ochads wee selected fo testing / measuements. Thee ae thee kinds of diect stesses to which timbe can be subjected; tensile, compessive and sheaing. Timbe is not isotopic and has thee stuctual axes and consequently has thee diffeent sets of values fo mechanical popeties in the thee diections (Silveste, 1967). The thee stuctual axes of wood ae longitudinal, adial and tangential. When consideing the stuctue of wood in elation to its stuctual axes, it is easy to appeciate the impotance of axes oientation in espect of mechanical popeties. The diffeence in the stength popeties of wood on the adial and tangential axes, howeve, is not consideed to be of significant impotance. It is usual, theefoe, in stuctual design to conside the stength of timbe only paallel with the gain, i.e. loaded in the diection of the longitudinal axis, o pependicula to the gain when loaded on the adial o tangential axes. To find which stesses should be measued the behavio of human and machines on the tee wee analyzed. Machines exet a adial stess and τ = μ, which is a longitudinal shea stess develops on the tunk as shown in Fig. 1. μ is the coefficient of fiction between the machine wheel and the tee. If a tee climbing machine is equipped with a pneumatic tie, the tie foot pint aea changes with load such that stays constant and equal to the tie inflation pessue. Measuement of fiction coefficient The aim of this expeiment was to establish the coefficient of fiction between the wheel of a tee climbing machine and the tee tunk suface. Thee leaf base samples wee pepaed using a hand saw. The test was done with thee eplications fo each sample. To simulate the eal condition, a piece of ubbe fom a tie was glued to a steel holde. The ubbe sample was loaded to 20 N. The weight of the ubbe holde and the ubbe sample was 2.1 N. The total weight of the unit was 22.1N. One end of a plastic ope was tied to the ubbe holde and the othe side to a sping balance. The sample was fixed onto the table by a clamp. The ubbe was placed on the sample and was pulled by the sping balance which displayed a maximum of 100 N with 1N esolution. At the l 20
Jounal of Agicultual Technology 2009, V.5(1): 17-31 point that the ubbe stats to slip ove the sample the amount of foce was ead fom the sping balance. Result of the test can be seen in Table 1. The tee suface is coveed with leaf bases on which the tie woks; theefoe, the adial compessive stess and longitudinal shea stess was measued fo both the tee suface (leaf bases) and the tee tunk. The minimum stess values can be used fo the design calculations of tee climbing date havesting machines. The human o machine applies thei total weight as an eccentic load to the tee. This phenomenon poduces vaying stess levels on diffeent pats of the tee. The maximum value of the stess was calculated fom the pinciples of columns stess analysis (Bee & Johnson, 1981). Accoding to this analysis the eccentic load of machine weight, W, on the tee which is consideed as a column can be eplaced with a cental load of the same value and a moment equal to the poduct of the load and the eccenticity as is shown in Fig. 2.Then the maximum tensile and compessive longitudinal stesses, t and c on the tee can be calculated fom the Eqns (2) and (3). W My t = A I (1) W My c = + A I (2) 2 Whee A is the tee coss section aea in mm2 and is equal to π in which is tee adius in mm. M is equal to W x, maximum moment and y is fathest element distance fom the neutal axes in the tee coss section which is 4 equal to the tee adius in mm. I is moment of inetia, equal to π 4 fo a cicula (tee) coss section. Nine tee tunk dates samples wee selected at andom fom diffeent locations within the tunk fo each test. Date palm tunk samples wee pepaed and tested. Bitish Standad 373 (1957), "Method of testing small clea specimens of timbe", was used to select the sample sizes and test methods. The tee tunk samples wee tested fo: Tensile stength in longitudinal diection, compessive stength in longitudinal diection, compessive stength in adial diection and shea stength in longitudinal diection. The leaf bases wee also tested fo: compessive stength in adial diection and shea stength in longitudinal diection. Leaf base adial compessive stength measuements To measue the maximum adial compession that the leaf bases on the live tee can toleate a tool was designed and constucted fo use in the field. As is shown in Fig. 3a, the tool compises mainly of a leve in the shape of an 21
angled beam. At one end (A) the angled beam is hinged to a plate which is attached to the tee and at the opposite end (C) weights ae suspended on the tool. The weight action pushes a 4 mm diamete pin at point B to the leaf base in the adial diection. The citeion to select the pin diamete was eaching the failue stess by suspending a easonable weight fom point C. Table 1. Hoizontal foce needed to pull the ubbe on the leaf base sample. Sample A B C Aveage Standad Replication I II III I II III I II III F h, N 17 18 17 21 20 20 19 18 19 18.8 1.4 M=Wx W W Machine pessue τ = μ 1 Tee tunk G x = Tee tunk Fig. 1. Stesses on a tee tunk (The adial compessive stess( ) and the longitudinal shea stess ( τ 1 )) Fig. 2. Machine o human load tansfomation on a tee tunk C F 265mm A Pin B 250 mm Bx Tee tunk Hinge plate Belt (a) Fig. 3. (a) Block diagam of the leaf base compessive stength measuing tool; (b) Date tee tunk leaf base compessive stength tool. (b) 22
Jounal of Agicultual Technology 2009, V.5(1): 17-31 Fig. 4. Tensile stength test on a fibe. A clock gauge connected to the tool is used to measue the depth of penetation of the pin into the leaf bases. It can be also used to daw the foce, penetation diagam fo the leaf bases. The pin clealy and suddenly penetated the leaf base at a specific load. The stess at the point of failue was ecoded as the maximum adial stess that can be toleated by the leaf base. The tool is held onto the tee by two belts which ae connected to the hinge plate and positioned aound the tee as can be seen in Fig. 3b. Afte tying the belts aound the tee and fastening them fou adjusting bolts ae used to align the plate in a vetical plane. The pin length should then be adjusted to ensue the tool lowe beam is hoizontal. Following these adjustments, the tool is eady to be loaded. To convet the loading at point C to the adial compessive stess at point B the Eqns (3) and (4) was used: = (Bx + tool weight eaction foce) / (pin coss section). (3) To find Bx a moment was taken about point A in Fig. 3a: M = 0 o 565 F - 250 Bx = 0 o Bx = 2.16 F. (4) A Using a sping scale showed that the tool weight exets a hoizontal foce equal to 7.5 N at point B. Substituting this value and Bx fom Eqn (4) in Eqn (3), fo a pin diamete of 4 mm: = 0.59 + 0.18 F (5) Equation (5) was used to convet the loading (F) at point C to the compessive stess in adial diection ( ) developed on the leaf base at point B. The esults of the loading F and convesion to compessive stength ae shown in Table 6 with a mean value of 6.38 MPa. In all tee loading conditions the safety facto (SF) is calculated fom the Eqn (6): SF= (stength/ applied stess) (6) 23
Results and discussion The inteactions between tee, human and machine ae summaized in the following headings: Coefficient of fiction between machine and tee tunk The coefficient of fiction ( μ ) could be calculated fom the Eqn(7): μ = F h F v (7) Whee F h is foce eading fom the sping balance and F v is the total weight of the unit. The test was caied out based on the method explained in pevious sections. Substituting 18.8 fo F h and 22.1 fo F v in Eqn (5) fom Table 1, μ has an aveage value of 0.85. Tee tunk tensile stength in longitudinal diection The tee tunk and bak ae composed mainly of bundled fibes which tansfe wate and nutients to the leaves and fuits. An individual fibe can cay consideable load. To measue the tunk tensile stength one fibe was sepaated fom each 20 20 300 mm sample and loaded by 1 N incement until sepaation (Fig. 4). The esults ae pesented in Table 2. The tensile stength fom Table 2, is equal to the aveage load that one fibe can cay until sepaation (68 N) multiplied by the aveage numbe of fibes pe unit of aea (0.88) which is 60 MPa. Table 2. Tee tunk longitudinal tensile stength. No. 1 2 3 4 5 6 7 8 9 Aveage Standad Foce, N 72 77 62 57 59 72 81 65 69 68 8 Fibes pe mm 2 0.92 0.83 0.95 0.90 0.89 0.92 0.85 0.80 0.87 0.88 5 Stength, MPa 66.24 63.9 58.9 51.3 52.51 66.24 68.85 52 60.03 60 Tee tunk longitudinal compessive stength The tee tunk test samples of 50 50 50 mm wee pepaed and loaded in longitudinal diection with a hydaulic pess until sample stats to defom and elease wate. The esults ae shown in Table 3 with an aveage stength of 5.34 MPa. 24
Jounal of Agicultual Technology 2009, V.5(1): 17-31 Table 3. Tee tunk longitudinal compessive stength. No. 1 2 3 4 5 6 7 8 9 Aveage Standad Load, N 13000 13300 13400 13300 13500 13200 13800 13500 13400 Aea, mm 2 2601 2525 2500 2500 2450 2575 2401 2500 2525 Stength,MPa 5.00 5.27 5.36 5.32 5.51 5.13 5.75 5.40 5.31 5.34 0.21 Tee tunk adial compessive stength The tee tunk compessive test was caied out by applying a foce in the adial diection, the samples of 50 50 50 mm failed due to shea foce which developed in the 45 plane elative to the compessive foce diection. The esults show that the aveage adial compessive stength is 2.96 MPa. (Table 4). Table 4. Tee tunk adial compessive stength. No. 1 2 3 4 5 6 7 8 9 Aveage Foce, N 7800 6800 7200 7300 7400 7300 7700 7500 7400 Standad Aea, mm 2 2500 2425 2474 2500 2523 2475 2525 2601 2425 Stength, MPa 3.12 2.80 2.90 2.92 2.93 2.95 3.05 2.88 3.05 2.96 0.10 Tee tunk longitudinal shea stength The hydaulic and mechanical pess could not measue the shea stength diectly. A shea tool was designed in ode to convet the compessive foce of the pess to shea foce. The pinciple involves, a moving jaw with an opposing stationay jaw; each jaw holds half of the sample. Loading the moving jaw ceates a shea foce equal to the compessive load on the sample in a vetical plane. Shea stength measuements wee conducted using this tool. Longitudinal samples of 20 20 20 mm wee cut fom the tunk fixed in the shea tool which was loaded gadually up to the beaking point whee in thee is complete shea occus in the sample. The esults ae shown in Table 5 with a mean value of 1.1 MPa. Leaf base adial compessive and longitudinal shea stengths The leaf bases wee tested fo compessive and shea stengths. The compessive test was done by the special tool designed and showed in Fig. 3a. 25
The esults of the loading, F, and convesion to compessive stength ae shown in Table 6 with a mean value of 6.38 MPa. The shea stength testing of the leaf bases was conducted employing the same method and tool used fo the tee tunk shea test. Sample sizes of 20 20 20 mm wee used fo the test. The esults ae shown in Table 7 with a mean stength value of 1.00 MPa. To show the typical use this study, the esults wee measued the safety factos fo a human and a machine. To calculate the woking stesses, Eqns (1) and (2) and data of Tables 1 to 7 wee used. The SF was calculated fom Eqn (6). The citical condition of stesses is when the human o machine with full equipments ae climbed and woked on a minimum diamete tee. Data of field measuements show that the minimum diamete of a poducing date tee is 280 mm (Al-Suhaibani et al., 1988). The expet man who climbed the tee plus his tools, at an eccentic distance of 500 mm, exets maximum 1300 N foce to the tee. Calculated FS fo this condition was calculated which vaies fom 11.5 to 198. An expeimental tee climbing date havesting machine insets 1880 N load at an eccentic distance of 300 mm to the tee (Shamsi, 1998). The esults show that the minimum SF when this machine climbs the tee is 7. It is fa fom 1, the citical SF. The complete esults ae tabulated in Table 8. Summay of some physical popeties and tee spacing of date palm tees ae tabulated in Table 9. Tee height is a key facto fo lifting height of any machine to lift a woke to the date palm cown fo cultual opeations. Results showed that the poducing tees height in studied aea was vaies fom 6.5-17 m with aveage of 10.3 m. Al-Suhaibani et al. (1988) ecoded tee height aveage of 7.4 m fo 6 vaieties of date palms in Saudi Aabia with minimum and maximum values of 1.00 and 17.43 m. Ahmed et al. (1992) measued height of date palm tees in diffeent locations in ange of 1.1-10.2 m. Fadl (2004) ecoded the aveage height of 4.9 m fo nine diffeent vaieties of poducing date palm tees with minimum and maximum values of 2.5 and 6.8 m in UAE. Fadl (2005) also epoted the aveage height of 2.9 m in thee UAE date palm cultivas. Keama et al. (2007) found the aveage height of 5.3 m fo Shahani vaiety of date palms in Ian that was in ange of 10-45 yeas old. Mazloumzadeh et al. (2007) ecoded the aveage height of 6.4 m fo most impotant vaiety of dates in Ian (Mozafati) with minimum and maximum values of 1.9 and 10.7 m. Tee yield is an impotant facto fo detemining payload capacity of any date havesting machine. Table 9 shows that the aveage and maximum tee yield wee about 67 and 128 kg espectively. Shamsi et al. (2005) found the aveage poduction of 85 kg fo Mozafati vaiety of dates. Consideing aveage 26
Jounal of Agicultual Technology 2009, V.5(1): 17-31 poduction of 20 kg pe tee in the Ian (Anon, 2003), thee is a significant diffeent between these data. The tee bunch and stalk weight and numbe of bunches ae also impotant factos fo detemining machine payload capacity in bunch cutting method is used whee all fuits on a bunch ipen simultaneously. The esults wee shown in Table 9. The aveage tees inte and inta ows spacing wee 5.8 and 4.6 m espectively and the aveage distance to neaest tee was 3.66 m. Al-Suhaibani et al. (1988) ecoded the aveage distance between tees about 5.71 m in ange of 5-6.8 m. They also showed aveage distance between neighboing tees about 3.89 m. Mazloumzadeh et al. (2007) found the aveage Mozafati cultiva tee spacing about 5.5 m. Table 5. Tee tunk longitudinal shea stength. No. 1 2 3 4 5 6 7 8 9 Aveage Standad Foce, N 425 390 410 450 405 455 430 415 470 Aea, mm 2 380 400 370 410 400 409 370 409 400 Stength, MPa 1.12 1.08 1.11 1.10 1.02 1.11 1.16 1.01 1.18 1.10 0.06 Table 6. Leaf base adial compessive stength. No. 1 2 3 4 5 6 7 8 9 Aveage Standad Foce, N 27 40 32 31 29 39 37 28 30 Stength, MPa 5.45 7.79 6.35 6.17 5.81 7.61 7.25 5.63 5.99 6.38 0.96 Table 7. Leaf base longitudinal shea stength. Standad No. 1 2 3 4 5 6 7 8 9 Aveage Foce, N 450 380 415 420 410 455 290 355 430 Aea, mm 2 400 390 400 400 390 380 410 430 410 Stength, 1.13 0.97 1.04 1.05 1.05 1.20 0.71 0.82 1.05 1.00 0.15 MPa Based on the analysis tee spacing showed significantly diffeences between inte ow, inta ow and distance to neaest tee spacing. It showed that the tee spacing is not standadized, so available machines may not achieve equied tuning cicle. It also indicated that most of date palm tees ae andomly planted and often inte copped with foage and vegetable cops and 27
sometimes inte copped with othe fuit tees such as citus.with espect to taditional cultivation methods and the valuable idea of cultivation of fuit tees such as oanges unde the shadow of palm tees, the available machines have some limitation in length, width and height. Table 8. Safety facto of stesses applied to the tee by human o machine. Type τ l Equation Human stess, MPa SF, human Machine stess, MPa Tee tunk SF, machine Tee tunk Leaf base = Machine pessue 0.17 17 38 τ μ l = 0.14 8 7 t Equation 1 0.302 0.406 198 148 c Equation 2 0.323 0.467 16.5 11.5 Table 9. Summay of some physical popeties and tee spacing of date palm tees. Poducing tees featues Tee tunk height, m Yield, kg Tee cicumfeence at gound, cm Tee cicumfeence at cown, cm Inte ow spacing, m Inta ow spacing, m Distance to neaest tee, m Bunch and stalk weight, kg Numbe of bunches Bunch cicumfeence, cm Bunch height, cm Leaf base pitch, cm Leaf base height, cm Woke climbing speed, m/sec City Gove name Vaiety Min Max Mean Standad 6.5 17 10.3 3.6 34.1 127.6 66.9 28.2 157 267 200.7 32.7 94.2 201.6 138.5 29.2 4.1 7.3 5.8 0.96 3.5 5.7 4.6 0.69 2.5 5.2 3.66 0.74 6 14.5 9.67 2.66 7 11 8 2 125.7 204.2 160.2 41.5 42 111 77.2 28.3 6 11.5 9.4 1.99 4.1 7.5 6 1 0.18 0.41 0.31 0.08 Bam, Shahdad Dehghan, Istghah, Sabzevay, Shahdadi, Baghe ig, Kohestani, Rahmani, Cha fasahk, Saheb dadi Mozafati, Kaoot, Ghasab, Pokoo, Bazmani 28
Jounal of Agicultual Technology 2009, V.5(1): 17-31 Tee cicumfeence is an impotant citeion fo designing U shape platfoms fo any date palm sevice machine. Results showed that tee cicumfeence at the gound vay fom 157-267 cm with aveage value of 200.7 cm, while aveage cicumfeence at cown was measued as 138.5 cm in ange of 94.2-201.6 cm. Al-Suhaibani et al. (1988) found that the aveages of date palm tee cicumfeence vay fom 130 to 180cm with maximum and minimum values of 256 and 90 cm in diffeent location. Ahmed et al. (1992) found the tee cicumfeence in anges of 116-172cm. Fadel (2004) epoted the aveage tee cicumfeence of 155cm in ange of 140-140 cm in nine UAE date palm cultivas. Fadl (2005) also epoted the aveage tee cicumfeence of 193 cm in ange of 170-210 cm in thee UAE date palm cultivas. Mazloumzadeh et al. (2007) ecoded the Mozafati date tee cicumfeence in ange of 150-226 cm with aveage of 190 cm. Leaf base pitch and Leaf base height paametes wee vey impotant factos fo designing any new date palm climbing machine stuctue and dimensions. Results ae shown in Table 9. The physical and mechanical popeties of the date palm tees ae necessay fo the design of appopiate equipments fo date palm cultual opeations. This study was conducted to find some impotant physical and mechanical popeties of date palm tees. The stength test esults ae summaized in Table 10. These ae the stength limits at which damage to the tee occus. To satisfy the tee safety any machine o human should exet foces and stesses lowe than these values. It is impotant to know that the fibes ae positioned in longitudinal diection and mostly paallel to each othe fo the whole length of the tee tunk. They exhibit poo esistance to longitudinal shea stess. It is also obvious fom the test esults. It is also impotant to conside that the leaf bases can toleate geate adial compessive stesses than the tee tunk; theefoe, the lowe stength value which is belong to the tee tunk must be adopted as the design citeion fo any tee climbing machine. Test esults in Table 8 show, high SF fo diffeent loadings on the tee by human and light tee climbing machines. It gives self confidence to a woke who climbs the tee and afaid of the tee tunk beakage. In the date palm cultual opeations industy, occasionally two o thee wokes climb the tee togethe, it educe the FS fo them. In some date palm tees, disease deceases the tee tunk cicumfeence and it also stongly educes the SF fo wokes. The Mechanical popeties findings can be used as a based knowledge fo wide ange of applications such as funitue and composites industies. Compaison between of the esults, date palm physical popeties showed that thee wee significant diffeences in tee height, spacing, yield and 29
cicumfeence between most impotant cultivation aeas aound the wold. It cleas that any new date palm sevice machine must be adopted with local cultivation conditions and any date palm cultivation in the aea needs diffeent mechanization equipments fom othes. Table 10. Stess test esults. Tee tunk Leaf base Aveage compessive stength in adial diection ( ), Mpa 2.96 6.38 Aveage shea stength in longitudinal diection ( τ l ), Mpa 1.10 1.00 Aveage tensile stength in longitudinal diection ( t ), Mpa 60 Aveage compessive stength in longitudinal diection ( ), Mpa 5.34 Refeences Abdalla, K.N., Hassan, O.S. and Ahmad, A.E. (1986). Developing of a walk elevato to suit date palms faming opeations. The 2 nd Symposium on Dates Palm in Saudi Aabia, King Faisal Univesity, Saudi Aabia. Abounajmi, M. (2004). Mechanization of dates fuit havesting. Ameican Society of Agicultual Enginees/Canadian Society of Agicultual Enginees, Annual Intenational Meeting, Ottawa, Canada. Ahmad, A.E., Alyhassan, O.S. and Khalil, M.M. (1992). Suveing of some date palm paametes and popeties to be utilized in date palm mechanization. Agicultual mechanization in Asia and Afica and Latin Ameica, 23(2), 67-69. Albozaha, A. (2003). Design, development and evaluation of a hand-held date palm dehoning device. Annual epot No: 82/Nakhl/119, Ahwaz, Date Palm and Topical Fuits Reseach Institute of Ian. Al-Kiady, H.K. (2000). Date palm tee (Pocessing and Agicultual Technology-Mechanical and Havesting of Dates). Pub.: Da Zahan, Oman. Al-Suhaibani, S.A. Babie, A.S. Kilgou, J. and Flynn, J.C. (1988). The design of a date palm sevice machine. Jounal of Agicultual Engineeing Reseach, 40(2): 143 157. Anon. (2003). Ianian Management and Planning Oganization. Economical, Social and Cultual Repot of Keman Povince fo 1381. Keman, Ian. http://www.mpog.i/english/index.htm Bee, F.P. and Johnston, E.R. (1981). Mechanics of mateial. McGaw Hill, New Yok. Bown, G.K. (1983). Date poduction and mechanization in USA. Poceedings of the Fist Symposium on the Date Palm, King Faisal Univesity, Al-Hassan, Saudi Aabia. BS 373. (1957). Method of testing small clea specimens of timbe. Bitish Standad Institution, London. Davis, A.T. (1997). Attempt at mechanical climbing of pals with special efeence to the coconut palm. Jounal of plantation cops, 5(1), 31-35. Fadl, M.A. (2004). Date Palm Tee Sevice Platfom. The Fouth Annual UAE Univesity Reseach Confeence, Depatment of Aid land Agicultue, Al-Ain, UAE. c 30
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