Granular materials used today in many engineering projects such as rockfill dams and railway have a wide variety of shapes. This shape variation ranges from very sharp to perfectly rounded.  The shape of the aggregates affects the mechanical properties of the grain, including fracture strength and internal friction angle. As a result, the mechanical behavior of the mass of granular materials depends on the shape of the grains. In order to investigate the effect of this property, different types of grains in the shapes of spheres, cylinders, cubes and pyramids, which include a wide range of shapes of natural aggregates, were made artificially in the size range of 1.5 to 2.0 cm. Small-scale uniaxial compressibility tests were performed on each of the grain shapes under the same conditions including initial porosity ratio and maximum stress and after each experiment, the stress-strain behavior and the amount of breakage were obtained using Hardin breakage factor. Then, the results evaluated using an analytical model proposed by McDowell et al. based on the law of conservation of energy. This model has 7 parameters which depend on the initial conditions of the grains, material, shape, size and fracture strength of the grains. Comparison and evaluation of the results indicates the ability of the analytical model in predicting the compressibility behavior of pyramidal grains. As the grains become angular, the compressibility and breakage of the materials increase. Also, with increasing the fracture surface energy of material, the effect of shape on compressibility decreases.

Sulfur polymer concrete (SPC) is a construction material composed of melted modified sulfur cement (MSC) and fine and coarse aggregates. This research investigated the effects of the quantity of MSC and curing time on the mechanical and physical properties of SPC. Samples were prepared using five levels of MSC and four curing times. The MSC used contained olefin hydrocarbon polymeric additive and the aggregates were those commonly used for conventional concrete. The mechanical and physical properties of the samples (compressive strength, yield point and Young's modulus, unit weight, voids in the aggregate and concrete air content) were determined. The results showed that increasing in the amount of MSC up to a specific threshold value (depending on aggregate gradation) improved the mechanical properties of samples. Beyond the threshold point, a decreasing trend was observed. The SPC in the present study gained an average of 70% of its 28-day compressive strength by three days from concrete placement. The greatest 28-day compressive strength was achieved using the densest aggregate gradation, a sufficient amount of MSC to fill voids in the aggregate and the maximum unit weight of SPC.

IntroductionDry beans (Phaseolus vulgaris L.) or common beans have been characterized as a nearly perfect food because of their high protein, fiber, perebiotic and vitamin B (Lymo et al, 1992; Geil et al., 1994). Dry beans can also be grown in a variety of eco-agricultural regions. As a result, dry beans are used throughout the world representing 50% of the grain legumes consumed as a human food source. Bean forms a good source of income for farm families. In Iran, bean is a major source of food security, readily available and popular food to both the urban and rural population. Of the different dry bean varieties grown in Iran; "Red, Naz, Goli and Sayad "account for vast majority in term of production and consumption. Although all the varieties contain similar major components (protein, fat, carbohydrates and minerals), each have unique minor physical, mechanical and biological profiles that can affect their functional food outcomes. Yet, dry bean is understudied with research programs remaining critically underfunded compared to other commodities. Therefore, the objective of this study was to provide physical, mechanical and biological information on Red dry bean as an important crop.
Materials and MethodsThe beans were selected and cleaned manually. It was ensured that the seeds were free of dirt, broken and immature once, and other foreign materials. The experiment was carried out for five irrigation methods (sub-surface trickle, surface trickle, sprinkler center pivot, solid set sprinkler and modified surface irrigation) and four water levels of crop water requirement (50%, 75%, 100% and 125%) on yield and physical and mechanical properties of red bean landraces in central of Iran. Experiments were conducted in a randomized complete block design with three replications for one year in Isfahan. In this research parameters such as geometrical diameter, sphericitypercent, angle of repose and grain strength were measured and the effect of experimental treatments on these parameters were investigated.
Results and Discussion Physical, mechanical and biological properties of agriculturally, nutritionally and industrially valuated seed materials are important in designing the equipment for harvest, transport, storage, processing, cleaning, hulling and milling. The analysis results showed that increasing the amount of using water, increased the grain volume. Else the irrigation systems showed different effects on kernel parameters. It was notable that none of the treatments of using water and irrigation systems did not affect the grain hardness. With increasing water requirement from 50% to 125%, the volume seeds of bean gradually increased from 647 cubic mm to 790 cubic mm. Most of bean seed volume with 876 cubic mm was achieved with 125% water requirement under sub-surface trickle irrigation system. The most of establishment angle of seed with 23.2 degree and friction coefficient with 0.387 was achieved under sub surface trickle irrigation respectively and the least of them with 20.4 degree and 0.355 was achieved under modified surface irrigation respectively. The results of statistical analysis of biological characteristics showed that only irrigation system had a significant effect on germination of seeds. The maximum percent of germination was 94.7% in modified irrigation system and then sub surface trickle, surface trickle, solid set and center pivot respectively.
Conclusion This study provided basic information on physical, mechanical and biological properties of common bean (Phaseolus vulgaris L.) The current investigation was conducted on dry red bean. Physical, mechanical and biological attributes including geometrical diameter, sphericity percent, angle of repose and grain strength, seed mass, seed size, seed density and seed germination were measured and the effect of experimental treatments on these parameters were also investigated. The results of this study are expected to be useful for plant breeders, consumers and the food industry.

Measuring the resistance and fracture force of materials is a basic and fundamental issue in designing of many agricultural equipment and machinery. In this study, the fracture force of four varieties of safflower seed cultivated in Iran at moisture content of 5.5% (w.b.) in both horizontal and vertical positions were determined. In the experiments a grain pressure test device (Instron) was used. The results showed that in horizontal loading position, the maximum fracture forcebelongs to Padideh variety (83 N) and then Goldasht variety (80.29 N), while the minimum fracture force belongs to Esfahan 28 variety (65.64 N). At vertical loading position the maximum and minimum fracture forces belong to Goldasht variety (50.74 N) and PS variety (34.64 N). By comparing the effects of loading positions (horizontal and vertical), the fracture force values for Goldasht variety are significantly more than those for other varieties. Therefore, Goldasht variety is preferred to other varieties because of its highest strength against mechanical damages. In all varieties, the fracture force of the seeds in horizontal loading position was about twice as much as in vertical loading position.

The rice crack is the most significant conversion drop in our country. Parboiling along with gelatinizing rice starch and filling the cracks of rice leads to increased rice grain resistance and finally, its crack percentage significantly decreases and the conversion coefficient and the percentage of healthy rice increases as well. Recently, the use of microwave in parboiling operation has been taken into consideration by researchers. In this study, the effect of four cultivar factors in two levels (Shroodi and Hashemi), the soaking temperature in two levels (60 and 70 C), the microwave power in two levels (600 and 900 W) and the duration of heating in two levels (2 and 4 min) on conversion coefficient and the percentage of healthy rice were examined. The results indicated that with increasing the soaking temperature, the conversion coefficient increases significantly. The conversion coefficient in Shiroodi cultivar was significantly higher than Hashemi cultivar. With increasing the microwave power, the percentage of healthy rice increased significantly. The highest conversion coefficient and the percentage of healthy rice in both cultivars were related to the soaking temperature of 60 C, the power of 900 W and the heating duration of 2 min.

عوامل مؤثر بر نيرو و انرژي براي جداكردن زيره از بوته زيرة سبزمحمد حسین سعیدی¬راد*، احمد طباطبائی¬فر و فوژان بدیعی*** نگــارنده مسئــــول، نشانی: مرکز تحقیقات کشاورزی و منابع طبیعی خراسان رضوی، ص. پ. 488، تلفن: 3822373 (0511)، پیا‌م‌نگار: saiedirad@yahoo. com** به ترتیب استادیار پژوهش بخش تحقیقات فنی و مهندسی مرکز تحقیقات کشاورزی و منابع طبیعی خراسان رضوی؛ استاد دانشکده مهندسی و فناوری کشاورزی دانشگاه تهران؛ و استادیار پژوهش مؤسسه تحقیقات فنی و مهندسی کشاورزی تاریخ دریافت: 20/6/88؛ تاریخ پذیرش: 15/12/88 چکیده زیرة سبز گیاهی یکساله و یکی از گیاهان زراعی مستعد برای مناطق خشک و نیمه‌خشک ایران است. زيرة سبز به¬ دلیل نیاز آبی کم و کوتاه بودن فصل رشد آن در سال¬های اخیر مورد توجه کشاورزان قرار گرفته است. زيرة سبز در زمان برداشت مقاومت كمي در برابر ريزش دارد و اگر توجه نشود بخش عمده¬اي از محصول از دست مي¬رود. دلیل ريزش دانه در حين برداشت يا قبل از آن، كاهش نيروي اتصال دانه به بوته است. لذا به منظور بررسي: الف) عوامل مؤثر بر مقاومت دو سطح (در امتداد محور طولی دانه و عمود بر آن) و ب) نوع زیره (دیم و آبی) بر نیرو و انرژی لازم برای جدا کردن دانه از بوته این تحقیق عملی شد. نتایج نشان داد که میانگین نیرو و انرژی لازم برای کندن دانه¬های زیره از بوته به ترتیب برابر 995/0 نیوتن و 747/0 میلی¬ژول است. همین مشخص شد که رطوبت مهمترين فاكتوري است كه نيرو و انرژي مورد نياز براي كندن دانة زيره را تحت تاثير قرار مي¬دهد به‌طوری‌که با افزایش رطوبت، نيرو و انرژی مورد نياز براي كندن دانه افزایش می¬یابد. نتایج بررسی اثرهای دوگانة جهت کندن و رطوبت نشان داد که بیشترین اختلاف بین سطوح مختلف جهت کندن، در رطوبت 9/5 درصد است. در صورت اعمال نیرو در جهت عمود بر محور دانه، نیرو و انرژی مورد نیاز برای کندن دانه به ترتیب 26 و 20 درصد نسبت به حالت اعمال نیرو در امتداد محور دانه کاهش می¬یابد. همچنین کمترین اختلاف بین سطوح مختلف سرعت، در رطوبت 9/5 درصد است و در سطح رطوبت 5/13 درصد، اختلاف بین هر سه سطح سرعت معنی¬دار و بیشترین تأثیر سرعت بر انرژی کندن دانه زیره در این رطوبت است. واژه¬های کلیدی انرژی کندن دانه، زیرة سبز، نیروی کندن دانهEffective Factors on Force and Energy Requirements for Picking Cumin SeedM. H. Saiedirad*, A. Tabatabaeefar and F. Badiee* Corresponding Author: Assistant Professor, Agricultural Engineering Research Department, Agriculture and Natural Resources Research Center, P. O. Box: 488, Khorasan Razavi, Iran. Email: saiedirad@yahoo. comCumin (Cuminum Cyminum) is an annual suitable for the dry and semi-dry areas of Iran. Recently, farmers have chosen to plant cumin because it requires less water and growth time. However, at harvest time, the resistance of cumin seed to shatter is low and, if careful attention is not paid to this fact, a major portion of the crop can be lost. When the connection force of the seed decreases, seed shatter falls. To investigate effective factors in shatter resistance, this study measured the force and energy required to pick cumin seeds. The effects of moisture content at three levels (5. 9, 13. 5 and 22%), picking rate at three levels (50, 200 and 500 mm/min), direction of picking at two levels (vertical and horizontal on axial seed) and type of plant at two levels (irrigation and no-irrigation planting) were studied on the force and energy requirements for picking cumin seed. The results showed that the mean force and energy requirement was 0. 955 N and 0. 747 mJ, respectively. It was shown that moisture is the most effective factor in relation to the force and energy requirements. As moisture content increased, the amount of picking force and energy increased significantly. An investigation of the double effects of moisture and picking direction showed that the greatest difference between direction levels was related to a moisture content of 5. 9%. At this moisture, vertical picking of the axial seed required decreased force and energy of 26% and 20%, respectively. An investigation of the effects of moisture and picking rate showed that the least difference between picking rate levels was related to a moisture content of 5. 9%. However, at moisture content 13. 5%, velocity had the greatest effect on the energy requirement and the three picking rate levels all showed significant differences.

Brown spot, caused by Bipolaris oryzae, is a devastating disease of rice which can cause yield loss in most rice-growing regions of the world. Breeding for disease resistance is the preferred strategy of managing brown spot. Hence, identification and subsequent development of disease resistance in rice genotypes are crucial. The field resistance of 95 rice genotypes to brown spot was evaluated under water and fertilizer stress during 2017 and 2018. Partial resistance was assessed through reaction type (disease rating) and epidemiological parameters estimates i.e. final brown spot index, area under disease progress curve and apparent infection rate. Disease rating, brown spot index, and area under disease progress curve detected differences in the responses of rice genotypes to disease under field condition, which could be used to study brown spot resistance. Among the genotypes tested, 22 genotypes were resistant to moderately resistant (23.16%) while majority were moderately susceptible to susceptible (76.84%). A significant correlation between leaf angle and area under disease progress curve indicated positive influence of leaf erectness on severity of brown spot disease. Results showed that leaf infection did not significantly affect the number of filled grains per panicle or hundred seed weight, but caused yield decline by decreasing the number of productive tillers. Nevertheless, the infection of rice genotypes from flowering to ripening stages decreased the number of filled grains per panicle and grain weight. The resistant genotypes identified in this study can be exploited for future rice breeding programs to develop promising resistant lines in management of the brown spot disease.