• Title/Summary/Keyword: combination tests

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Current Wheat Quality Criteria and Inspection Systems of Major Wheat Producing Countries (밀 품질평가 현황과 검사제도)

  • 이춘기;남중현;강문석;구본철;김재철;박광근;박문웅;김용호
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.47
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    • pp.63-94
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    • 2002
  • On the purpose to suggest an advanced scheme in assessing the domestic wheat quality, this paper reviewed the inspection systems of wheat in major wheat producing countries as well as the quality criteria which are being used in wheat grading and classification. Most wheat producing countries are adopting both classifications of class and grade to provide an objective evaluation and an official certification to their wheat. There are two main purposes in the wheat classification. The first objectives of classification is to match the wheat with market requirements to maximize market opportunities and returns to growers. The second is to ensure that payments to glowers aye made on the basis of the quality and condition of the grain delivered. Wheat classes has been assigned based on the combination of cultivation area, seed-coat color, kernel and varietal characteristics that are distinctive. Most reputable wheat marketers also employ a similar approach, whereby varieties of a particular type are grouped together, designed by seed coat colour, grain hardness, physical dough properties, and sometimes more precise specification such as starch quality, all of which are genetically inherited characteristics. This classification in simplistic terms is the categorization of a wheat variety into a commercial type or style of wheat that is recognizable for its end use capabilities. All varieties registered in a class are required to have a similar end-use performance that the shipment be consistent in processing quality, cargo to cargo and year to year, Grain inspectors have historically determined wheat classes according to visual kernel characteristics associated with traditional wheat varieties. As well, any new wheat variety must not conflict with the visual distinguishability rule that is used to separate wheats of different classes. Some varieties may possess characteristics of two or more classes. Therefore, knowledge of distinct varietal characteristics is necessary in making class determinations. The grading system sets maximum tolerance levels for a range of characteristics that ensure functionality and freedom from deleterious factors. Tests for the grading of wheat include such factors as plumpness, soundness, cleanliness, purity of type and general condition. Plumpness is measured by test weight. Soundness is indicated by the absence or presence of musty, sour or commercially objectionable foreign odors and by the percentage of damaged kernels that ave present in the wheat. Cleanliness is measured by determining the presence of foreign material after dockage has been removed. Purity of class is measured by classification of wheats in the test sample and by limitation for admixtures of different classes of wheat. Moisture does not influence the numerical grade. However, it is determined on all shipments and reported on the official certificate. U.S. wheat is divided into eight classes based on color, kernel Hardness and varietal characteristics. The classes are Durum, Hard Red Spring, Hard Red Winter, Soft Red Winter, Hard White, soft White, Unclassed and Mixed. Among them, Hard Red Spring wheat, Durum wheat, and Soft White wheat are further divided into three subclasses, respectively. Each class or subclass is divided into five U.S. numerical grades and U.S. Sample grade. Special grades are provided to emphasize special qualities or conditions affecting the value of wheat and are added to and made a part of the grade designation. Canadian wheat is also divided into fourteen classes based on cultivation area, color, kernel hardness and varietal characteristics. The classes have 2-5 numerical grades, a feed grade and sample grades depending on class and grading tolerance. The Canadian grading system is based mainly on visual evaluation, and it works based on the kernel visual distinguishability concept. The Australian wheat is classified based on geographical and quality differentiation. The wheat grown in Australia is predominantly white grained. There are commonly up to 20 different segregations of wheat in a given season. Each variety grown is assigned a category and a growing areas. The state governments in Australia, in cooperation with the Australian Wheat Board(AWB), issue receival standards and dockage schedules annually that list grade specifications and tolerances for Australian wheat. AWB is managing "Golden Rewards" which is designed to provide pricing accuracy and market signals for Australia's grain growers. Continuous payment scales for protein content from 6 to 16% and screenings levels from 0 to 10% based on varietal classification are presented by the Golden Rewards, and the active payment scales and prices can change with market movements.movements.

Effects of Preheating Treatment and Chitosan Addition on the Textural Properties of Korean Radish during Salting (무의 염장과정 중 조직감의 변화에 대한 예열처리 및 Chitosan 첨가효과)

  • Rhee, Hee-Seoup;Lee, Gui-Ju
    • Journal of the Korean Society of Food Culture
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    • v.9 no.1
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    • pp.53-59
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    • 1994
  • This study was attempted to investigate the effects of preheating treatment and chitosan addition on the textural properties of Korean radish during salting. For this study, we determined the changes in textural properties by compression, puncture, cutting tests respectively and the changes in pectin fractions were also determined. Sensory parameters such as hardness, crispness and toughness were evaluated by sensory analysis and their results were correlated with those by Instron. The results were as follows. The compression force of nonpreheated Korean radish was increased by chitosan addition, whereas that of preheated one was decreased during salting. The puncture force from all the samples of Korean radish decreased, however, chitosan addition showed higher puncture force. The cutting force of nonpreheated Korean radish increased during salting and those from nonpreheated and preheated ones were increased by chitosan addition. During salting hot water soluble pectin(HWSP) of nonpreheated Korean radish increased and 0.4% Na-hexametaphosphate soluble pectin(HXSP) and 0.05 N-HCl soluble pectin(HCISP) decreased respectively. However, HXSP was decreased by preheating treatment. On the contrary, the results were reversed by chitosan addition. Hardness and crispness of nonpreheated Korean radish decreased and toughness increased respectively during salting. However, toughness was decreased by preheating treatment and hardness was increased by chitosan addition. Compression and puncture forces were highly correlated with sensory parameters such as hardness and crispness, whereas cutting force was more correlated with toughness. From these results, it seems that the textural properties were improved by chitosan addition in both nonpreheated and preheated Korean radish. The preheating treatment was effective in the early stage of salting. However, combination of both treatments showed little effect during salting.

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The Review of Environment, Food and Exercise on Allergy Anaphylaxis (환경, 음식 및 운동 알레르기 반응에 대한 고찰)

  • Kwak, Yi-Sub;Baek, Young-Ho;Kim, Seung-Hyun;Kim, Young-Il;Yoo, Byung-In
    • Journal of Life Science
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    • v.20 no.1
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    • pp.147-152
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    • 2010
  • Exercise-induced anaphylaxis (EIA) is a physical allergy, sometimes severe, triggered by exertion following specific food intake. It was defined for the first time in 1980. EIA is associated with different kinds of exercise. The clinical manifestations progress from itching, erythema and urticaria to some combination of cutaneous angioedema and vascular collapse. Mast cell participation in the pathogenesis of this syndrome has been proved by the findings of an elevated serum histamine level during exhaustive exercise. As predisposing factors of EIA, a specific or even nonspecific sensitivity to food has been reported. Food-dependent exercise-induced anaphylaxis (FDEIA) is a distinct form of food allergy induced by physical exercise. It is typified by the onset of anaphylaxis during exercise which was preceded by the ingestion of the causal food allergens. The diagnosis of FDEIA is heavily dependent on clinical history. Allergy tests may need to be performed using a broad panel of food and food additives. As with food allergies, FDEIA diagnosis is based on interview, biological test and skin test. Prophylaxis aims to prevent a recurrence; the patient should be given an emergency kit to deal with any recurrent episodes. After the food allergen has been identified, it should be avoided for at least 4 to 5 hours before any exercise. Two cases of EIA are presented (EIA to circumstances; FDEIA) in this paper, The diagnosis, pathophysiology and therapy of FDEIA are also reviewed.

Screening Methods for Plant-Coating Materials and Transpiration Inhibitory Effect of Soybean Oil to Crops (식물 코팅 소재 선발법과 작물들에 대한 콩 오일의 증산 억제 효과)

  • Jung, In Hong;Park, No Bong;Kim, Sang-Yeol;Na, Young-Eun;Kim, Soon-Il
    • Korean Journal of Plant Resources
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    • v.27 no.4
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    • pp.380-391
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    • 2014
  • Plants as well as crops are damaged by a combination of the hot and dry winds that has been a major factor in the reduction of crop production. A means to protect them from damaging conditions is to consider a coating material. In this study, we established laboratory screening methods to find a coating material to protect a crop from rapid transpiration caused by various factors. In a test measuring the weight loss of kidney bean seedlings for 6 days, Avion treatments decreased its weight loss (P=0.05). Owing to long-time spend in completing this assay, we performed a more simple method using a cobalt chloride paper strip, which changes from blue to red colors under water condition. Beewax, guagum, paraffin liquid, soybean oil, and PE-635 gave a waterproofing effect above 37 and 43% at 0.5 and 1 h after treatment, respectively. However, these tested materials did not show significant waterproofing results at 2 h. Although the methods produced reasonable results, a screening method to obtain more objective data is needed. An alternative is to use an instrument that can detect the transpiration of crop leaves. In a preliminary test using barley leaves, a portable photosynthesis system showed transpiration inhibition of 2% soybean oil and 10 times-diluted Avion under field conditions. In another test using the leaves of maize seedlings and apricot tree, 2% liquid paraffin and plant oils such as apricot oil, linseed oil, olive oil, and soybean oil showed significant transpiration inhibition (P=0.05). Especially, paraffin liquid and soybean oil selected from above tests gave good transpiration inhibitory effects against rice at 2%. In addition, the mixture of 2% soybean oil and a spreader showed more elevated inhibition results comparing with soybean oil or the spreader alone indicating that the spreader may be attributed to more uniform diffusion of the hydrophobic material onto the leaf surface of maize seedlings. The hydrophobic material coated physically the stomata and cuticle layers on leaf surfaces of rice. These hydrophobic materials screened in this study are expected to be used as plant coating materials.

Evaluation of Tumor Registry Validity in Samsung Medical Center Radiation Oncology Department (삼성서울병원 방사선종양학과 종양등록 정보의 타당도 평가)

  • Park Won;Huh Seung Jae;Kim Dae Yong;Shin Seong Soo;Ahn Yong Chan;Lim Do Hoon;Kim Seonwoo
    • Radiation Oncology Journal
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    • v.22 no.1
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    • pp.33-39
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    • 2004
  • Purpose : A tumor registry system for the patients treated by radiotherapy at Samsung Medical Center since the opening of a hospital at 1994 was employed. In this study, the tumor registry system was introduced and the validity of the tumor registration was analyzed. Materials and Methods: The tumor registry system was composed of three parts: patient demographic, diagnostic, and treatment Information. All data were input in a screen using a mouse only. Among the 10,000 registered cases in the tumor registry system until Aug, 2002, 199 were randomly selected and their registration data were compared with the patients' medical records. Results : Total input errors were detected on 15 cases (7.5%). There were 8 error items In the part relating to diagnostic Information: tumor site 3, pathology 2, AJCC staging 2 and performance status 1. In the part relating to treatment information there were 9 mistaken items: combination treatment 4, the date of initial treatment 3 and radiation completeness 2. According to the assignment doctor, the error ratio was consequently variable. The doctors who 010 no double-checks showed higher errors than those that 010 (15.6%:3.7%). Conclusion: Our tumor registry had errors within 2% for each Item. Although the overall data qualify was high, further improvement might be achieved through promoting sincerity, continuing training, periodic validity tests and keeping double-checks. Also, some items associated with the hospital Information system will be input automatically In the next step.

Posterior Lumbar Interbody Fusion Using Posterolateral Placement of A Single Cylindrical Threaded Cage and Two Regular Cages : A Biomechanical Study (단일 나사형 Cage를 이용한 후방 요추체간 융합술과 두개의 나사형 Cage를 이용한 PLIF의 생체 역학적 비교)

  • Park, Choon Keun;Hwang, Jang Hoe;Ji, Chul;Kwun, Sung Oh;Sung, Jae Hoon;Choi, Seung Jin;Lee, Sang Won;Kim, Moon Kyu;Park, Sung Chan;Cho, Kyeung Suok;Park, Chun Kun;Yuan, Hansen;Kang, Joon Ki
    • Journal of Korean Neurosurgical Society
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    • v.30 no.7
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    • pp.883-890
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    • 2001
  • Objectives : An in vitro biomechanical study of posterior lumbar interbody fusion(PLIF) with threaded cage using two different approaches was performed on eighteen functional spinal units of bovine lumbar spines. The purpose of this study was to compare the segmental stiffnesses among PLIF with one long posterolateral cage, PLIF with one long posterolateral cage and simultaneous facet joint fixation, and PLIF with two posterior cages. Methods : Eighteen bovine lumbar functional spinal units were divided into three groups. All specimens were tested intact and with cage insertion. Group 1(n=12) had a long threaded cage($15{\times}36mm$) inserted posterolaterally and oriented counter anterolaterally on the left side by posterior approach with left unilateral facetectomy. Group 2(n=6) had two regular length cages($15{\times}24mm$) inserted posteriorly with bilateral facetectomy. Six specimens from group 1 were then retested after unilateral facet joint screw fixation in neutral(group 3). Likewise, the other six specimens from group 1 were retested after fixation with a facet joint screw in an extended position(group 4). Nondestructive tests were performed in pure compression, flexion, extension, lateral bending, and torsion. Results : PLIF with a single cage, group 1, had a significantly higher stiffnesses than PLIF with two cages, group 2, in left and right torsion(p<0.05). Group 1 showed higher stiffness values than group 2 in pure compression, flexion, left and right bending but were not significantly different. Group 3 showed a significant increase in stiffness in comparison to group 1 for pure compression, extension, left bending and right torsion(p<0.05). For group 4, the stiffness significantly increased in comparison to group 1 for extension, flexion and right torsion(p<0.05). Although there was no significant difference between groups 3 and 4, group 4 had increased stiffness in extension, flexion, right bending and torsion. Conclusion : Posterior lumbar interbody fusion with a single long threaded cage inserted posterolaterally with unilateral facetectomy enables sufficient decompression while maintaining a majority of the posterior elements. In combination with a facet joint screw fixation, adequate postoperative stability can be achieved. We suggest that posterolateral insertion of a long threaded cage is biomechanically an ideal alternative to PLIF.

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Bacterial Blight Resistant Mid-late Maturing Rice 'Manbaek' with High Grain Quality (벼흰잎마름병 저항성 고품질 중만생 벼 '만백')

  • Park, Hyun-Su;Baek, Man-Kee;Kim, Bo-Kyeong;Kim, Ki-Young;Shin, Woon-Chul;Ko, Jae-Kwon;Nam, Jeong-Kwon;Kim, Woo-Jae;Cho, Young-Chan;Ko, Jong-Cheol;Kim, Jeong-Ju;Kim, Hyun-Soon
    • Korean Journal of Breeding Science
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    • v.49 no.3
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    • pp.235-244
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    • 2017
  • 'Manbaek' is a bacterial blight resistant mid-late maturing rice cultivar with high grain quality. 'Manbeak' was derived from anther culture using the backcross combination, $Hopum^*2/SR30075$. 'Hopum' is a mid-late maturing rice cultivar with high grain quality and 'SR30075' is a pyramid line carrying three bacterial blight resistance genes. 'Manbaek' was selected through the pedigree method, yield trials, and local adaptability tests. 'Manbeak' carrying two bacterial blight resistance gene Xa3 and xa5 showed high-level and broad-spectrum resistance against bacterial blight. 'Manbaek' was resistant to K3a, mostly virulent race in Korea, and exhibited resistance reaction against 16 Korean bacterial blight isolates. 'Manbaek' was a mid-late maturing rice. The heading date of 'Manbaek' was August 19th, which was 5 days later than that of 'Nampyeong'. Manbaek' was a lodging-tolerant rice with short culm and dark green leaf. Due to the low viviparous germination, 'Manbaek' could be a useful material to prevent pre-harvest sprouting. 'Mabeak' was resistant to bacterial blight and rice stripe virus, but susceptible to other virus diseases and insect pests. The yield of 'Manbaek' was similar to 'Nampyeong'. 'Manbaek' showed excellent grain appearance and good tastes of cooked rice, so that it could contribute to improving the quality of bacterial blight resistant cultivars. 'Manbaek', bacterial blight resistant cultivar with high grain quality, is suitable for the cultivation at bacterial blight prone area and has been utilized in the breeding programs for enhancing the resistance against bacterial blight (Registration No. 6069).

Characterization of Traits Related to Grain Shape in Korean Rice Varieties (국내 육성 벼 품종 입형 관련 특성 분석)

  • Lee, Chang-Min;Lee, Keon-Mi;Baek, Man-Kee;Kim, Woo-Jae;Suh, Jung-Pil;Jeong, Oh-Young;Cho, Young-Chan;Park, Hyun-Su;Kim, Suk-Man
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.65 no.3
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    • pp.199-213
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    • 2020
  • Grain size and shape are the two important components contributing to rice yield and quality. To analyze traits related to grain-shape, a total of 272 varieties derived from japonica, japonica black and Tongil-type rice accession in Korea were evaluated in this study. The traits, grain length (GL), grain width (GW), grain thickness (GT), length to width ratio (RLW), and 1000-grain weight (TGW) were measured and replicated 10 times. Genes (GW2, GS3, qGL3, qSW5, GS5, TGW6, GW7, and GW8) related to grain-shape were validated in the accessions using specific DNA marker sets. K-mean clustering of the accession based on phenotypic data revealed three groups: group 1 was classified by GW and GT and included most of japonica type, group 2 was classified by RLW and GL reached a medium size and possessed a half spindle-shaped type, and group 3 was classified by TGW, reached a long size and possessed a semi-round shape. In validation tests using the marker sets, both gw2 and tgw6 were validated in less than 1% of the tested accessions and two allelic types, qgl3 and gw8, were only verified in Tongil-type accessions. For GW8 and GW2, any different amplicons were not amplified in any japonica or Tongil-type accessions, respectively. In order to suggest the representative grain-shape gene combinations for each ecotype, the allelic combinations were evaluated by PCR analysis. Cj1 and 2 in japonica (Cj1-7), Cj_b1 and 2 in japonica-black (Cj_b1-3), and CT3 in Tongil-type (CT1-13) turned out to be the dominant combination in each ecotype, respectively. In addition, the results revealed that introgression of four genes (gw2, gs3, qSW5, and GS5) would expand the diversity of grain shape in Korean japonica varieties. The gene combinations information could be utilized practically to understand or enhance grain shape in japonica rice breeding program.

A Rheological Study on Creep Behavior of Clays (점토(粘土)의 Creep 거동(擧動)에 관한 유변학적(流變學的) 연구(研究))

  • Lee, Chong Kue;Chung, In Joon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.1 no.1
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    • pp.53-68
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    • 1981
  • Most clays under sustained load exhibit time-dependent deformation because of creep movement of soil particles and many investigators have attempted to relate their findings to the creep behavior of natural ground and to the long-term stability of slopes. Since the creep behavior of clays may assume a variety of forms depending on such factors as soil plasticity, activity and water content, it is difficult and complicated to analyse the creep behavior of clays. Rheological models composed of linear springs in combination with linear or nonlinear dashpots and sliders, are generally used for the mathematical description of the time-dependent behavior of soils. Most rheological models, however, have been proposed to simulate the behavior of secondary compression for saturated clays and few definitive data exist that can evaluate the behavior of non-saturated clays under the action of sustained stress. The clays change gradually from a solid state through plastic state to a liquid state with increasing water content, therefore, the rheological models also change. On the other hand, creep is time-dependent, and also the effect of thixotropy is time-function. Consequently, there may be certain correlations between creep behavior and the effects of thixotropy in compacted clays. In addition, the states of clay depend on water content and hence the height of the specimen under drained conditions. Futhermore, based on present and past studies, because immediate elastic deformation occurs instantly after the pressure increment without time-delayed behavior, the factor representing immediate elastic deformations in the rheological model is necessary. The investigation described in this paper, based on rheological model, is designed to identify the immediate elastic deformations and the effects of thixotropy and height of clay specimens with varing water content and stress level on creep deformations. For these purposes, the uniaxial drain-type creep tests were performed. Test results and data for three compacted clays have shown that a linear top spring is needed to account for immediate elastic deformations in the rheological model, and at lower water content below the visco-plastic limit, the effects of thixotropy and height of clay specimens can be represented by the proposed rheological model not considering the effects. Therefore, the rheological model does not necessitate the other factors representing these effects. On the other hand, at water content higher than the visco-plastic limit, although the state behavior of clays is visco-plastic or viscous flow at the beginning of the test, the state behavior, in the case of the lower height sample, does not represent the same behavior during the process of the test, because of rapid drainage. In these cases, the rheological model does not coincide with the model in the case of the higher specimens.

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Mechanical and Operational Factors Affecting the Efficiency of Rice Polishing Machines (정미기의 능률에 미치는 기계적 요인및 작동조건에 관한 연구)

  • No, Sang-Ha
    • Journal of Biosystems Engineering
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    • v.1 no.1
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    • pp.15-15
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    • 1976
  • In analyzing the operational characteristics of a rice whitening machine, the internal radial pressure of the machine was measured using strain gage equipment. Changes in cylinder and feed screw configurations, screen type, cylinder speed and counter-pressure levels were examined to determine their impact on the quality and quantity of milled rice and the performance of the machine. The results are summarized as follows: 1. The internal radial pressure in the whitening chamber varied with the surface condition of the grain being processed. During the first or second pass through the machine, pressure was relatively low, reached a maximum after two to three passes with combinations I and II, three to six with combination III and then began to fall. 2. The pitch of the feed screw and the size of the feed gate opening which determine the rate of entry of grain into the whitening chamber, appeared to be the most important factor aff-::cting the degree of radial pressure, quality and quantity of milled rice and the efficiency of the machine. Using a feed screw with a wide pitch (4.8cm), radial pressure was relatively high and head rice recovery ratio \vere quite low. In this case capacity and machine effic?iency were much higher than obtained when using a feed screw with a narrow pitch (2.3cm). Very significant responses in radial pressure, head rice recovery rates and machine capacity were observed with changes in cylinder speed and counter-pressure levels when using the wide pitch feed screw. 3. The characteristics of the screen which surrounds the whitening chamber had an important effect on whitening efficiency. The existence of small protuberances on the original screen resulted in significant increases in both machine capacity and efficiency but without a significant decrease in head rice recovery or development of excessive radial pressure. Further work is required to determine the effects of screen surface conditions and the shape of the cylinderical steel roller on the rate of bran removal, machine efficiency and recovery rates. The size of the slotted perforations 0:1 the screen affects total milled rice recovery. The opening size on the original screen was fabricated to accommodate the round shape of Japonica rice varieties but was not suitable for the more slender Indica type. Milling Indica varieties with this screen resulted in a reduction in total milled rice recovery. 4. An increase in cylinder speed from 380 to 820 rpm produced a positive effect on head rice recovery for all machine combinations at every level of counter-pressure used in the tests. Head rice recovery was considerably lower at 380rpm using a wide screw pitch when compared to the results obtained at speeds from 600 to 820 r.p.m. The effects of cylinder speed On radial pressure, capacity and machine efficiency showed contrasting results, depending on the width of the feed screw pitch. With a narrow feed screw pitch (2.3cm), a direct proportional relationship was observed bet?ween cylinder speed and both radial pressure and machine efficiency. In contrast, using a 4.8 centimeter pitch feed roller produced a series of inverse relationships between the above variables. Based on the results of this study it is recommended when milling Indica type long grain rice varieties that the cylinder speed of the original machine be increased from 500-600 rmp up to a minimum of 800 rpm to obtain a greater abrasive effect between the grain and the screen. The pitch of the feed screw should be also reduced to decr?ease the level of internal radial pressure and to obtain higher machine efficiency and increased quality of milled rice with increased cylinder speeds. Further study on the interaction between cylinder speed and feed screw pitch is recommended. 5. An increase in the counter pressure level produced a negative effect On the head rice recovery with an increase in radial pressure, capacity, and machine efficiency over all combinations and at every level of cylinder speed. 6. Head rice recovery rates were conditioned primarily by the pressure inside the whitening chamber. According to the empirical cha racteristics curve developed in this study, the relationships of head rice recovery ($Y_h$) and machine capacity ($Y_c$/TEX>) to internal radial pressure ($X_p$) followed an inverse quadratic function and a linear function respectively: $$Y_h^\Delta=\frac{1}{{1.4383-0.2951X_p^\ast+0.1425X_p^{\ast\ast}}^2} , (R^2=0.98)$$$$Y_c^\Delta=-305.83+374.37X_p^{\ast\ast}, (R^2=0.88)$$The correlation between capacity and power consumption per unit of brown rice expressed in the following exponential function: $$Y_c^\Delta=1.63Y_c^{-0.7786^\{\ast\ast}, (R^2=0.94)$$These relationships indicate that when radial pressure increases above a certain range (1. 6 to 2.0 kg/$cm^2$ based On the results of the experiment) head ricerecovery decrea?ses in a quadratic relation with a inear increase in capacity but without any decrease in power consump tion per unit of brown rice. On the other hand, if radial pressure is below the range shown above, power consumption increases dramatically with a lin?ear decrease in capacity but without significant increases in head rice recovery. During the operation of a given whitening machine, the optimum radial pressure range or the correct capacity range should be selected by controlling the feed rate and/or counter-pressure keeping in mind the condition of the grain, particulary the hardness. It was observed that the total number of passes is related to radial pessure level, feed rate and counter-pressure level. The higher theradial pressure the fewer num?ber of pass required but with decreased head rice recovery. In particular, when using high feed rates, the total number of passes should be increased to more than three by reducing the counter-pressure level to avoid decreaseases in head rice recovery (less than 65 percent head rice recovery on the basis of brown rice) at every cylinder speed. 7. A rapid rise in grain temperature seemed to have a close relationship with the pressure generated inside the whitening chamber and, subsequently with head rice reco?very rates. The higher the rate of increase, the lower were the resulting head rice recoveries.