فهرست مطالب

نشریه ماشین های کشاورزی
سال دوازدهم شماره 4 (پیاپی 26، زمستان 1401)

  • تاریخ انتشار: 1401/09/29
  • تعداد عناوین: 12
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  • ایمان احمدی*، مریم گل آبادی، عبدالرضا اقتداری صفحات 453-466

    ایران با تولید سالانه 1.7 میلیون تن خیار، چهارمین تولیدکننده این محصول در سطح دنیاست، از سوی دیگر وجود بذر مناسب یکی از مهم ترین عوامل در افزایش تولید خیار است. در این پژوهش به درخواست یکی از شرکت های تولید بذر، دستگاهی برای استخراج بذر از محصول خیار بذری طراحی و ساخته شد و کارایی آن مورد ارزیابی قرار گرفت. اجزای کاری دستگاه دو مارپیچ چپ گرد و راست گرد هستند که در هنگام چرخش باعث خارج شدن پیوسته بذرها از داخل محصول خیار بذری می شوند. توان دورانی مارپیچ ها توسط یک موتور الکتریکی با قدرت یک اسب بخار تامین شد و به کمک سیستم انتقال توان پولی و تسمه ای به محور مارپیچ ها منتقل گردید. برای راه اندازی و توقف آرام موتور و امکان پذیر شدن تغییر سرعت آن، موتور الکتریکی به یک راه انداز الکترونیکی مجهز شد. برای ارزیابی دستگاه، ظرفیت و نرخ استخراج بذر توسط ماشین با پارامترهای مشابه در روش دستی مقایسه شد و مقدار محصول در نقطه سر به سر اقتصادی تعیین گردید. برمبنای نتایج به دست آمده به کارگیری دستگاه با ظرفیت کامل باعث کاهش 15 نفری در تعداد کارگران مورد نیاز برای استخراج بذر به روش دستی می شود. همچنین وزن محصول در نقطه سر به سر اقتصادی برابر با 7.7 تن برآورد شد که از نظر زمانی با به کار بردن دستگاه به طور مداوم به مدت 25.3 ساعت حاصل می شود.

    کلیدواژگان: تولید بذر، خیار گلخانه ای، ظرفیت ماشین، ماشین استخراج کننده بذر، نقطه سر به سر اقتصادی
  • احمد خالو احمدی، امیدرضا روستاپور*، علی محمد برقعی صفحات 467-480

    ارایه راه کارهای جدید برای بهبود فرایند و کاهش زمان خشک شدن و همچنین توسعه خشک کردن در مهار زباله های تر یکی از مسایل مهم در حفظ سلامت جامعه است. خشک کردن می تواند از طریق کاهش رطوبت، ذخیره سازی برای آینده، حمل و نقل آسان، بهبود ارزش های گرمایی و وابستگی کمتر به سوخت های فسیلی، کاهش بوی زباله، کاهش ضایعات و کاهش اثرات زیست محیطی را به دنبال داشته باشد. در این راستا جهت مطالعه رفتار خشک شدن ضایعات غذایی یک نمونه خشک کن کابینتی طراحی، ساخته و ارزیابی شد. توان حرارتی معادل 2.7kW به عنوان منبع گرمایش هوای ورودی تعیین شد. در این راستا طبق محاسبات انجام شده از یک فن گریز از مرکز با حجم هوای 310m3 h-1 ،2800rpm و 110pa برای ایجاد جریان هوا در خشک کن استفاده شد. سینی خشک کن دارای مجاری هواگذر میانی و جانبی بود. تاثیر سه سطح دمای 50 ،60 و 70 درجه سانتی گراد و سه سطح سرعت جریان هوای ورودی 1، 1.5 و  m s-12 بر مدت زمان، شدت خشک شدن و میزان مصرف انرژی خشک کردن ضایعات غذایی با ضخامتcm 3 مورد بررسی قرار گرفت و نمودارهای نسبت رطوبت و شدت خشک شدن استخراج شد. نتایج نشان داد تمام فرایند خشک شدن در دوره نزولی رخ داده است. مصرف انرژی در دمای 70 درجه سانتی گراد بیشترین و در دمای  50درجه سانتی گراد کمترین مقدار است. مقدار انرژی فعال سازی برای توده ضایعات غذایی در سه سطح سرعت، مقدار ثابت  10417.44J mol-1 به دست آمد. ضریب نفوذ رطوبت در دماهای 50 و 60 درجه سانتی گراد کمتر از دمای 70 درجه سانتی گراد بوده است زیرا با افزایش دما مقاومت سلولی کاهش یافته و نفوذ رطوبت افزایش می یابد.

    کلیدواژگان: انرژی فعال سازی، انرژی مصرفی، خشک کردن پسماندهای غذایی، خشک کن کابینتی، ضایعات غذایی، ضریب نفوذ رطوبت
  • علی نیازی، هیوا گل پیرا، هادی صمیمی اخیجهانی* صفحات 481-495

    یکی از بزرگ ترین مشکلاتی که در کشت بقولاتی مانند نخود وجود دارد، برداشت این محصولات با ریزش بسیار زیاد است. هدف از اجرای این پژوهش، برداشت مکانیزه نخود با تلفات کم و عملکرد مزرعه ای مناسب است. طراحی این ماشین به گونه ای است که همانند کمباین های متداول برداشت غلات قابلیت تنظیم موقعیت چرخ فلک نسبت به دماغه و تغییر ارتفاع را دارد. همچنین برای کاهش ریزش دانه ناشی از بازگشت محصول برداشت شده صفحه مشبکی به زیر چرخ فلک اضافه شد. در این تحقیق چرخ فلک برداشت نخود با هدف کاهش تلفات دانه مورد ارزیابی قرار گرفته و مدل سازی، تحلیل دینامیکی و استاتیکی چرخ فلک ماشین برداشت نخود انجام گرفته است. سامانه باز طراحی شده با تغییر عوامل تاثیرگذار شامل دماغه با صفحه مشبک و بدون صفحه مشبک، ارتفاع شانه برش نسبت به زمین در سه سطح 10، 15 و 20 سانتی متر و فاصله چرخ فلک از شانه در سه سطح 3، 5 و 7 میلی متر در سه تکرار مورد ارزیابی قرار گرفت. تحلیل آزمایش ها در قالب طرح کاملا تصادفی انجام شد. نتایج آماری نشان داد، استفاده از صفحه مشبک تاثیر معنی داری در سطح یک درصد بر مقدار برداشت و ریزش داشته است اما در مورد نخود باقی مانده بر روی بوته این اثر در سطح 5 درصد معنی دار شد. تاثیر ارتفاع دماغه از سطح زمین بر میزان برداشت در سطح 5 درصد معنی دار بود. همچنین اثر متقابل ارتفاع برداشت و صفحه مشبک نیز بر میزان ریزش در سطح 5 درصد معنی دار شد. بیشترین تاثیرگذاری بر نخود باقی مانده بر روی بوته در اثر فاصله بین چرخ فلک و دماغه به وجود آمد. علاوه بر آن برای بهینه سازی ابعادی اجزای چرخ و فلک از روش اجزای محدود سه بعدی با تحلیل تغییر شکل و شکست با معیار ون میسز (von-Mises) استفاده شد. به کمک مدل سازی رایانه ای و با توجه به تجزیه و تحلیل دینامیکی مدل جدید ی از چرخ فلک برای ماشین برداشت با هدف کاهش وزن، ارایه شد. در طرح ارایه شده با توجه به نیروی متقابل بین محصول و چرخ فلک ماشین برداشت نخود، میزان قابل توجهی از وزن چرخ فلک کاسته شد.

    کلیدواژگان: بهینه سازی، تنش، ریزش، صفحه مشبک، مدل سازی
  • فرخ معتضدیان، مرتضی تاکی*، روح الله فرهادی، مصطفی رحمتی جنیدآباد صفحات 497-513

    این تحقیق، به شبیه سازی جریان انرژی یک گلخانه نیمه مدفون نیمه دوطرفه با استفاده از متغیرهای بیرونی و داخلی و حل عددی به روش دینامیک سیالات محاسباتی (CFD) می پردازد. در این تحقیق، داده های دما، رطوبت و تابش به صورت لحظه ای اندازه گیری شد و سپس از CFD جهت بررسی توزیع انرژی و تغییرات دما در دو ارتفاع 1 و 2 متری از سطح زمین استفاده گردید. گلخانه مورد بررسی، به صورت یک گلخانه بسته در نظر گرفته شد و با توجه به روابط تجربی-ریاضی موجود در منابع، میزان دریافت، تلفات و خالص جذب شده انرژی در گلخانه محاسبه شد. نتایج این تحقیق نشان داد که روش CFD با 326030 المان چهار وجهی (tetrahedral) قادر است دمای هوای داخل گلخانه را با دقت مناسب در ارتفاع 1 متری (R2 = 0.987, MAPE = 2.17%) و 2 متری از کف (R2 = 0.987, MAPE = 2.28%) تخمین بزند. بررسی جریان انرژی نشان داد که این گلخانه، 6779.4 کیلوژول انرژی حرارتی انباشته ناشی از پرتوهای تابش را در مدت زمان آزمایش به زمین منتقل می کند و نسبت به سازه های روی سطح زمین، به طور متوسط حدود 40% تابش کم تری دریافت می کند. نتایج کلی این تحقیق و بررسی روند تغییرات دما در کف و دیواره ها نشان داد که در مناطق گرم کشور، زمین به عنوان منبع خوبی برای دریافت گرمای انباشته موجود در محیط گلخانه است و هرچه پوشش سطح داخلی گلخانه رسانایی گرمایی بیشتری داشته باشد، شار حرارتی به سمت عمق خاک بیش تر است.

    کلیدواژگان: انتقال حرارت، ذخیره انرژی، گلخانه نیمه مدفون، مدل دینامیکی
  • آرش مصری، فاطمه رحیمی اجدادی*، ایرج باقری صفحات 515-527

    سنجش از دور، یکی از ابزارهای کارآمد برای بررسی روند تغییرات سطح زیرکشت محصولات کشاورزی و باغی در سطوح وسیع و زمان کوتاه است. سیاست گذاران با آگاهی از این اطلاعات، می توانند تصیمات صحیح و به موقعی داشته باشند. مطالعه ی حاضر، با هدف تخمین سطح زیرکشت شالیزارهای برنج در بخش کیاشهر استان گیلان انجام شد. از تصاویر سنجنده TM ماهواره لندست 5 و سنجنده OLI ماهواره لندست 8 به منظور تهیه نقشه های کاربری اراضی استفاده شد. ابتدا، تصحیح هندسی و اتمسفری بر روی تصاویر صورت گرفت. سپس، با استفاده از الگوریتم طبقه بندی نظارت شده حداکثر احتمال، نقشه های کاربری اراضی منطقه با هفت کاربری شامل اراضی برنج، جنگل نیمه انبوه، جنگل تنک، مناطق مسکونی، مناطق آبی، پهنه های ماسه ای و سایر اراضی تهیه شد. در ادامه، مساحت هر یک از کاربری ها محاسبه شد و روند تغییرات، مورد مقایسه قرار گرفت. دقت کلی و ضریب کاپای طبقه بندی به ترتیب معادل 98.45% و 0.98 برای سال 2000، 97.59% و 0.97 برای سال 2010 و 98.72% و 0.98 برای سال 2020 به دست آمد. نتایج نشان داد که اراضی برنج در یک بازه 20 ساله، با کاهش 6.94 درصدی همراه بوده، به طوری که مساحت آن از 11080.66 هکتار در سال 2000 به 10311.69 هکتار در سال 2020 رسیده است. همچنین، در این مدت مناطق مسکونی و جنگل های تنک به میزان 67.94 و 18.73 درصد رشد کرده اند، اما جنگل های نیمه انبوه، مناطق آبی و پهنه های ماسه ای به ترتیب 61.32، 4.91 و 61.48 درصد کاهش داشتند. با توجه به نتایج، توجه جدی به تغییر کاربری اراضی برنج و تخریب جنگل ها ضروری می باشد.

    کلیدواژگان: حداکثر احتمال، جنگل تنک، طبقه بندی نظارت شده، کاربری اراضی
  • حسنی محمدی منور*، سمانه زیبازاده صفحات 529-542

    استفاده از تکنیک سنجش از دور امروزه در کشاورزی کاربردهای فراوانی دارد ازجمله تعیین سطح زیرکشت و پیش بینی عملکرد محصول. در این پژوهش از تصاویر ماهواره ای جهت تفکیک گندم آبی و دیم در استان همدان استفاده شد. شاخص های NDVI ،EVI و NDWI از تصاویر 16 روزه سنجنده های لندست، مادیس و سنتینل 3 در بازه پنج ساله مورد مطالعه (2015-2019) استخراج گردید. نتایج شاخص ها نشان داد کاهش شدید NDVI/EVI بعد از نقطه اوج به دلیل آن است که زمان زرد شدن و یا برداشت محصول فرا رسیده است. به علاوه NDWI به ترتیب در بیشینه سبزینگی گندم در کشت آبی و دیم 0.767 و 0.736 دیده شد. سامانه Google Earth Engine محیط انجام محاسبات پردازش تصاویر و استخراج شاخص ها و نقشه ها بود و نرم افزار R نیز برای آنالیزهای طبقه بندی و تفکیک کشت دیم و آبی به کار رفت. نتایج نشان داد نقشه استان بر اساس سطح زیر کشت دیم و آبی ماهواره سنتینل 3 جزییات بیشتری را نشان داد. همچنین استفاده همزمان از چند شاخص NDVI ،EVI و NDWI توانست قدرت تفکیک را افزایش دهد. علی رغم شباهت های موجود، الگوریتم های SVM و MD نیز با دقت قابل قبولی تفکیک کشت دیم و آبی استان را ارایه دادند. نتایج نشان داد کشت دیم و آبی گندم استان با دقت 0.737 تفکیک شد و تفکیک گندم از سایر کشت ها با دقت 0.945 انجام گردید.

    کلیدواژگان: تصاویر ماهواره ای، تفکیک کشت دیم و آبی، شاخص های سبزینگی، گندم
  • فاطمه نادرنژاد، دین محمد ایمانی*، محمدرضا رسولی صفحات 543-558

    پیش بینی عملکرد محصول یکی از مسایل مهم در حوزه ی کشاورزی می باشد و به عوامل مختلفی از جمله شرایط آب وهوایی، ویژگی های خاک، ویژگی های محصول و برنامه های مدیریتی وابسته می باشد. پیش بینی دقیق عملکرد محصول می تواند در تصمیم گیری ها و بهینه سازی فرآیندها به کشاورزان و صنایع وابسته به کشاورزی کمک نماید و در نهایت منجر به افزایش تولید شود. نیشکر یکی از مهم ترین محصولات استراتژیک کشاورزی و منبع تامین شکر در جهان می باشد. هدف پژوهش حاضر پیش بینی و بررسی عوامل موثر بر میزان شکر استحصالی از نیشکر در مزارع شرکت کشت وصنعت نیشکر امیرکبیر با استفاده از الگوریتم های یادگیری ماشین می باشد. داده های جمع آوری شده برای این پژوهش مربوط به بازه زمانی سال های 1396-1389 شامل 3223 نمونه می باشد که شامل چهار مجموعه داده آب وهوایی، محصول، خاک و مدیریت مزرعه می باشد. برای مدل سازی پژوهش از الگوریتم های جنگل تصادفی، آدابوست، تقویت گرادیان حداکثری و ماشین بردار پشتیبان استفاده شده و در محیط ژوپیترنوت بوک پایتون پیاده سازی شده اند. مدل جنگل تصادفی با صحت 92.2% برای پیش بینی شکر استحصالی در بین مدل های ارایه شده بهترین عملکرد را دارد.

    کلیدواژگان: طبقه بندی، کشاورزی دقیق، مدل سازی، یادگیری ماشین
  • سید رضا موسوی سیدی*، سید محمدرضا میری صفحات 559-574

    در میان سوخت های جایگزین، سوخت بیودیزل به عنوان یک گزینه مناسب برای موتور دیزل محسوب می شود. در این مطالعه، سوخت بیودیزل از روغن های پسماند آشپزخانه به روش ترانس استریفیکاسیون تولید شد. بیودیزل تولیدی در نسبت های 5 و 10 درصد حجمی با سوخت دیزل مخلوط و بر روی موتور دیزل چهار سیلندر چهار زمانه تزریق مستقیم در سرعت های rpm 1100 تا rpm 1400 با گام rpm 100 تحت بار کامل در دانشکده مهندسی مکانیک دانشگاه علوم دریایی امام خمینی (ره) نوشهر آزمایش شد. سپس جنبه آزمایشگاهی با مطالعه شبیه سازی انجام شده با استفاده از نرم افزار GT-Power اعتبارسنجی شد. نتایج نشان می دهد توافق خوبی بین نتایج شبیه سازی و آزمایشگاهی وجود دارد که حداکثر خطا در گشتاور 6.3 درصد، مصرف سوخت ویژه 4.8 درصد و در آلاینده های NOx و CO 5.6 درصد یافت شد. نتایج شبیه سازی نشان داد که با افزایش سرعت موتور و افزایش درصد سوخت بیودیزل مخلوط نسبت به سوخت دیزل خالص برای بیودیزل مخلوط B10، گشتاور موتور به میزان 4.4 درصد افزایش و مصرف سوخت ویژه به میزان 4.45 درصد کاهش یافت. از طرفی در مقایسه با سوخت دیزل، آلاینده NOx، 1.8 درصد افزایش و آلاینده CO، 37.67 درصد کاهش یافت. نتایج شبیه سازی و آزمایشگاهی نشان داد که سوخت B10 عملکرد بهتری را ارایه می دهد و نیز میزان آلایندگی موتور را به میزان قابل توجهی کاهش می دهد. همچنین فرایند شبیه سازی به دلیل کاهش هزینه ها و افزایش سرعت محاسبات می تواند نسبت به روش های آزمایشگاهی هزینه تحقیق را کاهش دهد.

    کلیدواژگان: روغن پسماند آشپزخانه، مدل ترمودینامیکی، نرم افزار GT-Power، ویژگی های موتور
  • امین ویسمرادی، محمداسماعیل خراسانی فردوانی*، هوشنگ بهرامی، سید محمد صفی الدین اردبیلی، حسن ذکی دیزجی صفحات 575-585

    امروزه تعداد موتورهای دیزل به دلیل داشتن بازده زیاد و تولید گازهای گلخانه ای کم، در حال افزایش است. در پژوهش حاضر تاثیر افزودن نانوسلولز به سوخت دیزل بر پارامترهای عملکردی و آلایندگی موتور دیزل مورد ازریابی قرار گرفت. مقادیر نانوسلولز در 3 سطح صفر و ppm25 و ppm75 در نظرگرفته شد. آزمون های موتور در 3 دور موتور 1600، 2000 و 2400 دور بر دقیقه در حالت بار کامل انجام گرفت. به منظور اندازه گیری پارامترهای عملکردی و آلایندگی موتور، از تجهیزات مختلفی شامل دینامومتر، دستگاه اندازه گیری آلاینده ها و سیستم کنترل موتور استفاده شد. نتایج نشان داد که افزایش دور موتور در تمام ترکیب های سوختی باعث افزایش در توان موتور، مصرف سوخت ویژه، مونواکسیدکربن، هیدروکربن های نسوخته ولی مقدار گشتاور موتور، کاهش یافت. همچنین در هر دور موتور افزودن مقادیر مختلف نانوسلولز، مقدار توان و گشتاور موتور را افزایش داد، اما باعث کاهش مصرف سوخت ویژه، مونواکسیدکربن و هیدروکربن های نسوخته شد. مقدار NOX با افزایش دور موتور افزایش یافت ولی در هر دور موتور افزودن ppm25 نانوسلولز به دیزل خالص به میزان قابل توجهی مقدار NOX را افزایش داد. اما در دورهای پایین، افزایش ppm75 نانوسلولز به دیزل خالص باعث کاهش مقدار NOX نسبت به دیزل خالص شد، اگرچه از لحاظ آماری معنی دار نیست. به طور کلی نتایج این پژوهش نشان داد که افزودن نانوسلولز به سوخت دیزل می تواند سبب  بهبود عملکرد و کاهش گازهای آلاینده خروجی از موتور دیزل شود. اگر چه افزودن ppm25 نانوسلولز به دیزل خالص به میزان قابل توجهی مقدار NOX را افزایش داد.

    کلیدواژگان: اکسیدهای نیتروژن، توان، موتور دیزل، نانوسلولز
  • هوشنگ محبوب ینگجه، عارف مردانی کرانی* صفحات 587-599

    در این مطالعه به بررسی نیروی کششی تیغه پنجه غازی در دو بخش شبیه سازی به روش اجزای محدود با تحلیل اویلرین- لاگرانژی و آزمون های تجربی در محیط انباره خاک پرداخته شد. از دو تیغه با فاصله cm 35 و در سه عمق 6، 10 و 14 سانتی متری با سرعت 2.5 کیلومتر بر ساعت استفاده شد. نیروی کششی تیغه طی شبیه سازی در عمق های 6، 10 و 14 سانتی متر به ترتیب 0.6، 2.5 و 3 کیلونیوتن بوده و نسبت به نتایج انباره خاک دارای محدوده خطای 7.3، 5.6 و 4.16 درصد بود. بیشترین تنش ایجاد شده در خاک در سه عمق 6، 10 و 14 سانتی متر به ترتیب در حدود 20، 68 و 69 کیلوپاسکال بوده است. در عمق 6 سانتی متر با توجه به نرم بودن خاک، نیروی عمودی وارده بر تیغه متاثر از وزن خاک بوده است. همچنین بررسی گسترش تنش در خاک حاکی از آن بوده است که با افزایش عمق کار، مقدار به هم خوردگی سطحی خاک و همچنین انتشار تنش به سطح خاک کاهش می یابد. علاوه بر چگونگی تغییرات تنش، هم پوشانی دو تیغه مجاور نیز با افزایش عمق کار ازنظر به هم خوردگی خاک، کمتر می شود. با توجه به افزایش نیروی کششی تیغه در عمق های بالاتر، عمق کار بیشتر از 10 سانتی متر بر اساس نتایج مربوط به چگونگی توزیع تنش در خاک توصیه نمی شود. در همین رابطه، توان مصرفی هر تیغه در عمق کمتر از 10 سانتی متر در حدود 0.4 کیلو وات بوده است درحالی که در عمق های بالا در حدود 2 کیلو وات برای هر تیغه توان لازم است.

    کلیدواژگان: برهم کنش خاک-تیغه، خاک ورزی، روش المان محدود، کولتیواتور
  • آزاده حیدریان، ابراهیم احمدی*، فرشاد دشتی، احمد نورمحمدی صفحات 600-612

    تاثیر تیمارهای اتمسفر اصلاح شده (N2%85O2+%10CO2+%5)، پوشش کیتوزان و فیلم های بسته بندی در دو دمای نگهداری 4 و 25 درجه سانتی گراد بر فاکتورهای فیزیکوشیمیایی (pH و TSS) و خواص مکانیکی شامل تنش برشی (TB)، نیروی برشی (FB)، مدول برشی (GK) محصول بامیه در پایان 12 روز از زمان نگهداری تحت آزمون فاکتوریل در قالب طرح کاملا تصادفی مورد ارزیابی قرار گرفت. بیشترین تغییرات TSS در نمونه های با پوشش فیلم نانو پلی اتیلن رخ داد که از 0.6 به 1 افزایش یافته است. نتایج نشان دهنده عملکرد مناسب پوشش کیتوزان همراه با فیلم نانو امولسیون در حفظ و تثبیت مواد جامد محلول می باشد. تغییرات pH برای نمونه های نگهداری شده در دمای 4 درجه سانتی گراد کمتر بود، این امر ناشی از کنترل شدت تنفس محصول و ایجاد اتمسفر مطلوب بود. بیشترین pH در فیلم پلی اتیلن سبک (6.6) و کمترین pH مربوط به فیلم نانو امولسیون سیلیکونی (6.4) بود. مقدار pH به دلیل کنترل شدت تنفس و فسادپذیری در شرایط اتمسفر اصلاح شده کاهش یافت. در بررسی خواص مکانیکی مشخص شد که تغییرات تنش برشی نمونه های با پوشش نسبت به نمونه های بدون پوشش در مقایسه با ابتدای دوره نگهداری بسیار کمتر بود. حداقل تغییرات نیروی برشی مربوط به نمونه های با پوشش فیلم پلی اتیلن سبک و نمونه های با پوشش فیلم نانو امولسیون سیلیکونی به مقدار 0.57 و 1.28 درصد گزارش شد و حداکثر تغییرات برای نمونه های بدون پوشش فیلم نانو پلی اتیلن، 24.85 درصد بود. نمونه های نگهداری شده در دمای 4 درجه سانتی گراد نسبت به نمونه های مشابه در دمای 25 درجه سانتی گراد دارای میزان نیروی برشی کمتری در طول دوره نگهداری بودند. اتمسفر اصلاح شده موجب گردید، مقدار مدول برشی با پایان زمان انبارداری در مقایسه با ابتدای دوره نگهداری از 260.9 کیلوپاسگال به 219.8 کیلوپاسگال کاهش یابد. به طورکلی پوشش های پلی اتیلن و نانو امولسیون سیلیکونی بر خصوصیات فیزیکوشیمیایی (PH و Tss) و مکانیکی بامیه تاثیری نداشتند و نسبت به روز اول بسته بندی کم ترین تغییر را ثبت کردند. این نشان می دهد که پوشش های بسته بندی با اتمسفر اصلاح شده کیفیت بامیه بسته بندی شده را حفظ می کنند. بنابراین فیلم های نانو امولسیونی، پوشش کیتوزان به همراه اتمسفر اصلاح شده می توانند به عنوان یک تکنیک بالقوه برای کاربردهای فعال بسته بندی مواد غذایی مورد استفاده قرار گیرند.

    کلیدواژگان: اتمسفر اصلاح شده، بامیه، فیلم بسته بندی نانو، کیتوزان
  • حسین امیری، عباس عساکره*، محسن سلیمانی صفحات 613-626

    این مطالعه به منظور بررسی اثر سرعت پیشروی کمباین و عملکرد مزارع گندم بر میزان افت کمباین کاه کوب و تحلیل اقتصادی استفاده از این نوع کمباین ها، در شهرستان ازنا انجام شد. کمباین های مورد بررسی، مدل های جاندیر 1055 و 1165 بودند. آزمایش ها به صورت اسپلیت فاکتوریل در قالب طرح بلوک های کامل تصادفی و در سه تکرار انجام شدند که عملکرد مزارع گندم به عنوان عامل اصلی و دو تیمار مدل کمباین کاه کوب و سرعت پیشروی کمباین ها به صورت فاکتوریل در کرت‏های فرعی قرار گرفتند. ظرفیت کمباین و اختلاف درآمدهای حاصل از برداشت با کمباین کاه کوب و معمولی محاسبه گردید. نتایج نشان داد علاوه بر اثرات اصلی، اثر متقابل دوگانه و سه‏گانه تیمارها نیز بر صفات ریزش دماغه، افت های بدنه کمباین، انتهای کمباین، واحد کوبنده، واحد تمیزکننده، افت کل کمباین و افت کیفی کمباین کاه کوب معنا‏دار می باشد. افت کمباین کاه کوب به شدت متاثر از سرعت پیشروی و عملکرد مزارع (تغذیه) است. در مجموع، میزان افت کمباین کاه کوب حدود 2.22% بیش تر از کمباین معمولی به دست آمد که بیش ترین افت مربوط به افت انتهای کمباین کاه کوب بود. بررسی اقتصادی نشان داد که در مناطقی که دامپروری در کنار زراعت رواج دارد و کاه ارزش اقتصادی بالایی دارد، استفاده از کمباین کاه کوب اقتصادی تر از کمباین معمولی است.

    کلیدواژگان: افت کیفی، بررسی اقتصادی، عملکرد گندم، کاه
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  • I. Ahmadi *, M. Golabadi, A. R. Eghtedari Pages 453-466
    Introduction

    According to FAO, gherkin and cucumber have been cultivated in about 2.23 million hectares of farmlands around the globe, and about 78000 hectares of Iran agricultural fields have been devoted to gherkin and cucumber cultivation. However, large amounts of the cucumber seeds required in Iran have been imported from abroad. Fortunately, some Iranian agricultural companies have been focused on seed production recently. Therefore, there is an opportunity to develop seed production equipment such as seed extracting machines.There are two types of cucumber seed extractors: bulk seed extractor and single fruit extractor. The bulk seed extractor is suitable for extraction of large amounts of seed on the farm, while the single fruit extractor is suitable where seed production is limited to greenhouse seed-producing facilities which are mostly used for controlled pollination of the crop.Due to the high price of imported seed extractors, especially after increasing the price of foreign currencies, production of these machines within the country is economically rational; therefore, the aim of this research is to develop and evaluate a single fruit cucumber seed extractor for small and medium-size seed-producing greenhouses.

    Materials and Methods

    The cucumber seed extractor was designed semi-automatically. The criteria for designing the machine were as follows: 1- usage of the single fruit seed extraction method, 2- the possibility of simultaneous usage of two operators, 3- automatic discharge of the extracted seeds, 4- the possibility of the height variation of the machine, 5- the possibility of the emergency shutdown of the machine, 6- the possibility of the angular velocity variation of the machine helix.The working element of the machine was the rotating helix that can extract the fruit seeds and leave the fruit's outer skin mostly intact for easy disposal of fruit remains from the greenhouse. A 1 hp, 3 phase electric motor was used to drive the machine via the belt and pulley transmission system. For the smooth start and stop of the machine, and the possibility of angular velocity variation of the machine helixes, an electronic driver was used for the motor.To design the machine helix, the dimensions of the examined cucumber were measured first (i.e., cucumber length and diameter); then, according to the physical and mechanical properties of the fruit, the prime mover and transmission system of the machine was designed. Finally, the fabricated machine was evaluated using some mechanization criteria.

    Results and Discussion

    Some of the results are as follows:The total torque required to drive the machine was 3.394Nm.The electric motor power should be higher than 0.284hp; furthermore, in order to have a wider angular velocity span for the rotating shaft, a 1hp electric motor was installed on the machine.The diameter of the rotating shaft was calculated to be 15mm.The seed extracting machine could be used instead of 15 workers of the manual seed extraction method.The rate of seed extraction using the machine was 30781 kg ha-1.The efficiency of seed extraction using the machine was similar to that of the manual method.The emergence percentage of seeds obtained by the machine was similar to that of the manual method.The amount of crop calculated from the concept of economical break-even point was 7 tons.

    Conclusion

    In this study, an apparatus for mechanized extraction of cucumber seed was designed, fabricated and evaluated. The working element of the machine is the extractor helix that is rotated via the belt and pulley transmission system, which is activated using a 1 hp, 3 phase electric motor. For smooth start and stop of the motor, as well as the possibility of angular velocity variation of the machine helix, the motor was equipped with an electronic driver. Utilizing an emergency shutdown switch, the machine can be protected from unforeseen emergency situations. After using the machine for 6 months, it was recognized that strengthening the extractor helixes was necessary. According to the results of this study, using the machine led to 15 person reduction in the labor needs of the manual cucumber seed extraction method. Moreover, the amount of crop calculated from the economical break-even point was 7.7 tons.

    Keywords: Seed production, Greenhouse Cucumber, seed extracting machine, machine capacity, economical break-even point
  • A. Khalo Ahmadi, O. R. Roustapour *, A. M. Borghaee Pages 467-480
    Introduction

    Providing new solutions to control wet waste is one of the most important issues in maintaining public health. Drying will reduce the harmful effects on the environment by reducing moisture and the smell of wastes as well as easy transportation and disposal costs. The purpose of the design and development of the household dryer is to dry food waste in order to reduce its volume and prevent the spread of its pollution in the air, water, and soil. To study the drying behavior of food waste, an experimental cabinet dryer was designed, fabricated, and evaluated for drying food waste.

    Materials and Methods

    The dryer consisted mainly of the drying chamber, electric heater, fan, air inlet channel, mesh tray, air distribution plates, temperature sensor, and control panel. Different parts of the dryer were made of a stainless galvanized sheet. The dryer was modeled using Catia 2019 software and its various parts were designed. The heating power was calculated as 2.7 kW. A centrifugal fan with an air volume of 310 m3h-1, 2800 rpm, and 110 Pa was used to supply airflow in the dryer. In the drying process, a tray with medium and lateral air passage was fabricated and applied. Food waste was obtained from fruit and vegetable waste, homemade food, and fruit shops. And nonfood items such as glass, paper, plastics, and metals were separated from the waste and crushed with a shredder, and reduced to sizes less than 20 mm. First, the product was placed in the environment for one hour and then pressed with a mechanical press with the same pressure to eliminate part of the water. An anemometer UT363 model made in China was used to measure the air velocity. The temperature was measured and controlled by a temperature thermostat of G-sense model made in Iran. The effect of three temperatures of 50, 60, and 70 °C and three inlet velocities of 1, 1.5, and 2 m s-1 on the kinetics and intensity of drying of food waste and energy consumption of food waste with a thickness of 3 cm was investigated. Moisture ratio and drying intensity diagrams were extracted. Diffusion, activation energy, and energy consumption were determined.

    Results and Discussion

    Drying kinetics diagrams showed that temperature had a significant effect on moisture variation of food waste during drying. Drying period decreased with increasing temperature. The slope of the drying intensity diagrams increased with the increase of the dryer temperature. Drying rate was decreased at the temperature of 70 °c and it had a steeper slope that indicates the more intensity of the drying process in this condition. The drying process of all three samples occurred in the falling rate stage. The air duct on the side and in the middle of the tray caused hot air conducted above the tray and increased energy consumption. Effective moisture diffusivity of food waste during the drying process was in the range of 3.65×10-9-4.56×10-9 (m2 s-1). The effective moisture diffusivity at temperatures of 50 °C and 60 °C was less than 70 °C. Because at the temperature of 70 °C, the membrane resistance of the cell destroyed by high heat and increased the diffusion coefficient in the material.

    Conclusion

    Increasing temperature caused the drying period decreased and the drying occurred in the falling rate stage. Temperature and the interaction of velocity and temperature had a significant effect on the drying process. The highest drying intensity and the lowest drying time were observed at the temperature of 70 °C and a velocity of 2 m s-1. Energy consumption had the maximum value at the temperature of 70 °C and a velocity of 2 m s-1 and a minimum value at the temperature of 50 °C and a velocity of 1 ms-1. The amount of activation energy for the food waste mass at three velocities was equal to 10417.44 J mol-1.

    Keywords: Activation energy, Cabinet Dryer, Energy Consumption, Food waste drying, Moisture diffusivity
  • A. Niazi, H. Golpira, H. Samimi Akhijahani * Pages 481-495
    Introduction

    One of the biggest problems in growing legumes like peas is harvesting these types of crops. During the machine harvesting process the harvest loss is very high. Therefore, in most parts of Iran chickpea harvested by hand and this is very tedious. Based on the literature review there are different types of harvesting machines which designed, constructed and optimized by Miller et al., 1990; Golpira, 2015; Shahbazi, 2011; Jalali and Abdi, 2014; Mahamodi, 2016. But using different varieties of chickpea in mountainous areas has limited the use of harvesting mechanisms. The purpose of this study is mechanization of the harvesting process of chickpea with low losses and suitable performance. Moreover the optimization process of lowering the weight of the header was carried out by modeling of software.

    Materials and Methods

    To reduce the amount of chickpea losses from the reel, a perforated plate with defined holes was installed in the header, where the separated chickpea pods fell behind the plate without returning to the farm. By using the plate in the header of the chickpea harvesting machine and by changing the harvesting height at the three levels of 10, 15 and 20 cm and the distance of the cutter at three levels of 3, 5 and 7 mm, the performance of the machine was evaluated. The experiments were carried out with Caboli variety cultivated in Kurdistan province, which is proper for mountainous areas without regular watering condition in three replications. The plants were placed in a fiber, wooden plate considering farm conditions. In addition, the header was modeled statically and dynamically under the influence of the external forces applied to the header using Ansys and Abaqus software. Based on the actual data, the validity of the applied model was determined and according to the verification results the optimization of the header was performed considering minimal weight (to reduce energy consumption).

    Results and Discussion

    The evaluation results of the performance of header showed that the effects of using perforated plate and the height of the header for harvesting on the chickpea harvesting and losses are significant at the level of 1% and 5%, respectively, and the interaction between perforated plate and the header height on the chickpea loss is significant at 5%. Using a perforated plate in the harvesting machine increases the amounts of chickpea collected from the farm increases. In this condition the chickpea pods separated from the plant and passed through the plate. With the separation of the stems, due to the proper wear that exists between the plate and the reel, the pods are properly separated and pass through the perforated plate. Moreover, the chickpea loss is higher for the system without perforated plate. The effect of the distance between the reel and header plate is affects the remaining chickpea on the plate. By increasing the distance from 5 mm to 7 mm the amount of harvested had a considerable effect. The best method of harvesting chickpeas is at the kinematic index of 1.5 with perforated plate, the harvesting height of 15 cm and the distance of 5 mm. According to modeling processes of the reel and the results of the static analysis, the minimum and maximum stress values were recorded about 3.31 MPa and 6.50 MPa (based on the von misses criteria), respectively, which is very small compared to the yield stress of the reel constructed with St-37. Also, the results of the dynamic analysis of the reel showed that the maximum von misses stress occurred with increasing the kinematic index. The maximum stress for kinematic index of 1, 1.5 and 2 was observed about 32.2, 40.1 and 52.72 MPa, respectively. The results of 3D model validation showed that the applied model with Abaqus software (R2>0.9264) was able to predict the amount of stress in different parts of the reel.

    Conclusion

    In this study, the changes were made on the chickpea harvesting machine to get the proper performance and increasing machine efficiency. A perforated plate was used to prevent pea’s losses. The best condition for the harvesting process is obtained with the harvesting height of 15 cm and the distance of 5 mm. By using 3D modeling of the reel weight was reduced about 10%.

    Keywords: Loss, Modeling, Optimization, Perforated plate, Stress
  • F. Motazedian, M. Taki *, R. Farhadi, M. Rahmati-Joneidabad Pages 497-513
    Introduction

    Greenhouse cultivation is the popular intensive kind of crop production with a yield per cultivated unit area more than 10 times higher compared to field crops. Greenhouse production requires the use of large amounts of energy, water, and pesticides and it usually generates huge quantities of wastes to be disposed of it. Investment, labor, and energy costs per unit area are much higher in the greenhouse industry than in any other agricultural sectors. Sustainable greenhouse systems, socially supportive, commercially competitive, and environmentally sound, depend on cultivation techniques, equipment management, and constructive materials that aim to reduce agrochemicals, energy and water consumption as well as waste generation. The management of the greenhouse environment is depending on temperature manipulation. Temperature manipulation is critical to influencing plant growth, quality, and morphology and so is a major strategy in the environmental modification of crops. Heterogeneous indoor microclimate of a greenhouse has long become a matter of concern in many studies. It is believed to be unfavorable for crop growth, which damages crop activity, particularly transpiration and photosynthesis, one of the major causes of non-uniform production and quality. Since early and conventional methods are not sufficient to evaluate microclimate variables inside a greenhouse, Computational Fluid Dynamics (CFD) approach was applied for better and more accurate results. CFD is an effective numerical analysis technique to predict the distribution of the climatic variables inside cultivation facilities. Numerous studies have focused on the internal temperature, humidity, solar radiation, and airflow inside multiple cultivation facilities. For example, the CFD method was used to simulate natural ventilation for agricultural buildings and improve crop production systems. The CFD simulation and evaluation models could be applied for evaluation of the inside situation and temperature in greenhouses. Thermal and water vapor transfer is influenced by the openings of greenhouses in the CFD simulation. The CFD model was developed to predict the distribution of temperature, water vapor, and CO2 occurring in a Venlo-type semi-closed glass greenhouse equipped with air conditioners. Based on the above literature, this research aims to evaluate the energy flow and modeling of an un-even semi-buried greenhouse using external and internal variables and numerical solutions by the CFD method.

    Materials and Methods

    In this study, Computational Fluid Dynamic (CFD) solution was applied to evaluate the inside environment of a semi-double glass greenhouse with an east-west location. This greenhouse has a special structure that is used in very hot or very cold areas due to its depth of more than one meter below the ground. The greenhouse has an area of 38m2 and an air volume of 78.8m3. The temperature and humidity data were collected from inside and outside the greenhouse by temperature sensors (SHT 11 model made by CMOS USA). Irradiation data were collected inside the greenhouse, on level ground, by the TES132 radiometer.

    Results and Discussion

    In this study, the CFD method was used for a model solution with ANSYS Fluent version 2020R2 software. To evaluate the predictive capability of the model and its optimization, the comparison between actual (ya) and predicted values (yp) was used. Three criteria of RMSE, MAPE, and R2 were also used to evaluate the accuracy of the final model. The results showed that the dynamic model can accurately estimate the temperature of the air inside the greenhouse at a height of 1 m (R2 = 0.987, MAPE = 2.17%) and 2 m (R2 = 0.987, MAPE = 2.28%) from the floor. The results of energy flow showed that this greenhouse transfers 6779.4.4 kJ of accumulated thermal energy to the ground during the experiment.

    Conclusion

    In the present study, the computational fluid dynamics method was used to simulate the internal conditions of an un-even semi-buried greenhouse with external and internal variables including temperature and solar radiation. The results showed that this greenhouse structure is able to transfer part of the increase in temperature caused by sunlight to the soil depth (104.214 kJm-2 heat through the floor, 178.443 kJm-2 through the north wall and 113.757 kJm-2 through the south wall). By increasing the thermal conductivity of the inner surface of the greenhouse, the heat flux to the depth of the soil can be increased.

    Keywords: Dynamic model, Energy storage, Heat transfer, Semi-buried greenhouse
  • A. Mesri, F. Rahimi-Ajdadi *, I. Bagheri Pages 515-527
    Introduction

    Rice is the fourth most consumed grain worldwide. In recent years, monitoring the area under rice cultivation; as a strategic crop in Gilan province has become more important because of the uncontrolled migration of residents of the southern provinces to it. Remote sensing is one of the practical tools to study the trend of changes in the area under cultivation of agricultural and horticultural products on a large scale and in a short time. This technique can help policymakers to make true and timely decisions. The aim of this study is to estimate the area under rice cultivation in Kiashahr county of Gilan province.

    Materials and Methods

    The images of the TM sensor of Landsat 5 satellite and the OLI sensor of Landsat 8 satellite were used to prepare land use maps. First, geometric and atmospheric corrections were made to the images. Then, supervised classification using the maximum likelihood algorithm was used to prepare land use maps for each year. Seven main classes/land covers, based on the available data of the area were determined: rice-land, semi-dense forest, sparse forest, built-up area (towns and other urbanized areas), waterbody, sandy area and other areas. Then, the area of each land use was calculated by GIS, and their changes were compared.

    Results and Discussion

    Overall accuracy and kappa coefficient of classification were 98.45% and 0.98 for 2000, 97.59% and 0.97 for 2010, and 98.72% and 0.98 for 2020, respectively. According to the results, rice land area decreased by 4.42% from 2000 to 2010. It also had a decrease of 2.64% between 2010 and 2020. In total, rice lands decreased by 6.94% between 2000 and 2020, so its area has decreased to 10311.69 hectares. This downward trend can be due to the conversion of rice land to the built-up area. The area of semi-dense forest decreased by 47.48% between 2000 and 2010, but its downward trend decreased to 26.36% between 2010 and 2020. In total, semi-dense forest area decreases by 61.32%, equal to 682.25 hectares over a period of 20 years. This is due to the uncontrolled cutting of trees and the change of land use from semi-dense forests to sparse forests and built-up areas. Also, during this period, built-up areas and sparse forests have grown by 67.94% and 18.73%, respectively. But, semi-dense forests, water bodies and sandy areas have decreased by 61.32%, 4.91% and 61.48%, respectively.

    Conclusion

    The reduction rate in the area of rice land and semi-dense forest classes between 2010 and 2020 was lower than the ten-year period before, which can be attributed to the adoption of restrictive laws and more inspections by relevant organizations. However, the downward trends in these land uses have continued over the past decade. Meanwhile, the increase of 67.94% of built-up lands indicates that the lost lands in the forest and rice land classes have been converted into the built-up area. The rate of land-use change in the built-up class has the highest rate among the studied classes. This result indicates the need for serious attention to land-use change in the rural area more than before. Another point is that there was a growth in sparse forests between 2000 and 2010, and then a reverse trend was observed between 2010 and 2020, which shows that in a period of 10 years, deforestation has taken place, and in 10 years later, the lands from these destructions have been converted to the built-up area. As a result, serious attention to natural resource organizations is necessary. It is considered that there was a deliberate destruction of forests over time with the aim of personal profit.

    Keywords: land use, Maximum Likelihood, Sparse forest, Supervised Classification
  • H. Mohamadi-Monavar *, S. Zibazadeh Pages 529-542
    Introduction

    Remote sensing methods for mapping farms and crops have been widely used in the last three decades. This method is applied to identify irrigated areas around the world (Alipour et al., 2014), although most of these studies are in areas with semi-arid climates and low rainfall or lack of rainfall which has a significant effect on the spectral characteristics of plants. In this study, Landsat 8 and MODIS satellite images were used to identify and separate two irrigated and rain-fed wheat farms in Hamadan province. Two algorithms of support vector machine (SVM) and minimum distance (MD) were used simultaneously to classify irrigated and rain-fed farms. In the next step, the area under cultivation of rain-fed and irrigated wheat was predicted in the whole cultivated area of Hamadan province. Finally, the cultivation area of rain-fed and irrigated crops was calculated in the province using Sentinel 3 satellite images based on the random forest algorithm in 2016.

    Materials and Methods

    The study area is Hamedan province, which is located between 59◦ 33′ and 49◦ 35′ north latitude and also from 34◦ 47′ to 34◦ 49′ east longitude of the Greenwich meridian. A 50-hectare rain-fed wheat farm in Amzajerd was used as a sample to extract the properties of rain-fed wheat. Also, irrigated indices were extracted from a 100-hectare irrigated wheat farm located in Kaboudrahang. Satellite images were applied to separate irrigated and rain-fed wheat in Hamadan province. NDVI, EVI and NDWI indices were extracted from 16-day images of Landsat, MODIS, and Sentinel 3 sensors in the five-year period (2015-2019). Google Earth Engine (GEE) system was the environment for performing image processing calculations and extracting indices and maps.

    Results and Discussion

    The NDVI and EVI of irrigated and rain-fed wheat farms were calculated in 2015-2019. A small peak was observed in the rain-fed and irrigated NDVI trend in November due to the early germination of wheat leaves in winter, and the larger peak in May and June showed the maximum greenness of irrigated and rain-fed wheat, respectively. The ascending or descending trend of NDVI / EVI had no constant slope. This can be due to changes in meteorological parameters, which sometimes cause a sudden increase or decrease in the values of these indices. Despite the non-linearity of the NDVI / EVI trend over time, the maximum greenness was recorded just a month before the wheat harvest, which was seen in the third decade of May to the first decade of June. One of the cases is the sharp drop of NDVI / EVI after its final peak, which was definitely due to yellowing wheat and harvesting. Since the distinction between rain-fed and irrigated crops was difficult only based on NDVI, NDWI was also used to determine the water content of wheat so that irrigated wheat could be identified. However, the difference between rain-fed and irrigated wheat in terms of NDWI spectral density was insignificant; the maximum and minimum occurrence times of NDWI and NDVI of rain-fed and irrigated wheat were chosen for their separation. In order to map the cultivation area, in addition to the MODIS sensor, Sentinel 3 was used due to its ability to detect chlorophyll accurately. Due to the fact that the imaging of the Sentinel 3 satellite started since 2016, the map of rain-fed and irrigated cultivation as well as the cultivation area and their separation was done based on the random forest algorithm in 2016.

    Conclusion

    The results of this study showed that the appropriate method for distinguishing between rain-fed and irrigated wheat is the simultaneous use of several indices. Also, the greatest difference is in the maximum greenness, which happened almost one month before harvest. MD and SVM classification algorithms could distinguish irrigated and rain-fed wheat from other crops with 90% and 80% accuracy, respectively. Distinguished maps of irrigated and rain-fed crops based on the random forest algorithm were obtained using Sentinel 3 satellite imagery which can show the fertility of agricultural lands in the province.

    Keywords: distinguishing of rainfed, irrigated, Satellite Images, vegetation indices, wheat
  • F. Nadernejad, D. M. Imani *, M. R. Rasouli Pages 543-558
    Introduction

    Sugarcane is a strategic agricultural product and increasing productivity and self-sufficiency in its production is of special importance. The most important product of sugarcane is sugar. Various factors like climatic and management conditions affect the yield of sugarcane and recoverable sugar. Crop yield forecasting is one of the most important topics in precision agriculture, which is used to estimate yield, match product supply with demand and manage product to increase productivity. The purpose of this study is to predict and model the factors affecting sugar extracted from sugarcane (recoverable sugar) in the farms of Amir-Kabir sugarcane agro-industry Company of Khuzestan province using machine learning methods.

    Materials and Methods

    To conduct this study, data from the agro-industrial company Amir-Kabir in the province of Khuzestan from 2010 to 2017 were used. This data has 3223 records which include four sets of data: climate, soil, crop and farm management. This data includes continuous and discrete variables. Discrete variables include production management, soil type, farm, variety, age (cane class), the month of harvest and times irrigation. Continuous variables include area, chemical fertilizer consumption, water consumption per hectare, total water consumption, drain, crop season duration, yield (cane yield) soil EC, purity, time interval drying off to crop harvest, precipitation, min and max temperature, min and max relative humidity, wind speed and evaporation. The recoverable sugar variable is considered as the target variable and is divided into two classes, values greater than or equal to 9 are in the optimal class and less than 9 are in the undesirable class. The other variables are considered as predictor variables. For modeling using the Holdout method the data were randomly divided into two independent sets, a training set and a test set. 70% of the data which includes 2256 records were used for training and 30% of the data which includes 967 records were used for testing. The modeling of this study was performed with the Python programming language version 3.8.6 in the Jupyter notebook environment. Random Forest, Adaboost, XGBoost and SVM (support vector machine) algorithms were used for modeling.

    Results and Discussion

    To evaluate the models, metrics of accuracy, precision, recall, f1 score and k-fold cross validation were used. The XGBoost model with 94.8% accuracy on the training set and the Adaboost model with 92.4% accuracy on the test set, are the best models. Based on precision and recall metrics Adaboost model with 87% precision and SVM model with 87% recall have better performance than the other models. Based on Repeated 10-fold stratified cross validation using two repeats the SVM model with 92.3% accuracy is the best model. The variables of purity, time interval drying off to crop harvest and crop season duration are the most important variables in predicting the recoverable sugar.

    Conclusion

    In this study a new approach based on machine learning methods for predicting recoverable sugar from sugarcane was presented. The most important innovation of this study is the simultaneous consideration of management and climatic factors, along with other factors such as soil and crop characteristics for modeling and classification the recoverable sugar percentage from sugarcane. The results show that the performance of all models is acceptable and machine learning methods and ensemble learning algorithms can be used to predict crop yield. The results of this study and the analysis of the rules obtained from the set of decision trees made in the random forest model can be used for managers of different agro-industries in determining appropriate strategies and preparing the conditions to achieve optimal production.For future research as well as policy making and decision making Amir-Kabir sugarcane agro-industry Company the following suggestions are offered: more samples can be used to obtain more reliable results. Also can be used Deep learning methods, time series analysis and image processing. Use of IOT equipment to collect and real-time processing data on Amir-Kabir sugarcane agro-industry farms.

    Keywords: Classification, Machine learning, Modeling, Precision agriculture
  • S. R. Mousavi Seyedi *, S. M. R. Miri Pages 559-574
    Introduction

    Increasing industrialization, growing energy demand, limited reserves of fossil fuels, and increasing environmental pollution have jointly necessitated for exploration of a substitute for conventional liquid fuels. Vegetable oils can be used as alternatives to petroleum fuels for engine operation. These oils are mixtures of free-fatty acid molecules to contain carbon, hydrogen, and oxygen atoms. The ability to simulate the process of converting chemical energy to heat, energy users of computational fluid dynamics software in the design, analysis, and optimization of high-tech tools. Also, simulation saves time and reduces costs, workforce, and the space required.

    Materials and Methods

    In this research, a one-dimensional computational fluid dynamics solution with GT-Power software was used to simulate a four-cylinder, four-stroke, direct injection diesel engine to study the performance and exhaust emissions characteristics with different speeds and blends at full load. The engine speeds were chosen to be 1100 to 1400 rpm at an interval of 100 rpm. Also, fuel blends such as diesel (as a base), B5, and B10 biodiesel were selected for engine testing. To model a engine, we should have the dimensions of the engine, input air collection, output gases collection, the amount of sprinkled fuel, valves properties, combustion, and some of the estimates corresponding to the cylinder’s thermodynamic parameters when opening the output and input gate and to exchange the heat inside the cylinder as the input data. The model mainly consisted of an air cleaner, intake valve, exhaust valve, intake and exhaust port, injection nozzle, engine cylinder, and engine. Engine cylinder’s intake and exhaust ports are modeled geometrically with pipes. Before this investigation was carried out, a validation model for evaluation was done by experimental and simulation data. The validation results showed that the software model error is acceptable.

    Results and Discussion

    The engine performance and emissions were evaluated in terms of engine torque, specific fuel consumption, NOx, and CO emission at different engine speeds and fuels at full load. The results showed that with increasing the engine speeds, torque increased. On the other hand, the maximum engine torque for the diesel engine is slightly lower than the biodiesel-blended that increased by 4.4% because of the higher density and viscosity of biodiesel than diesel. Specific Fuel Consumption (SFC) is a measure of the fuel efficiency of any prime mover that burns fuel and produces rotation, or shaft, power. The results indicated that by increasing engine speeds, the SFC increased. A fuel with a lower heating value should be injected with more mass into the engine. This will increase the SFC. So, the maximum engine SFC for the diesel engine is more than the biodiesel-blended that decreased by 4.45% because of better fuel combustion and more power generation of biodiesel than diesel. The only nitrogen oxide that can be formed in an engine combustion temperature is nitrogen monoxide (NO). This pollutant factor can be converted to nitrogen dioxide (NO2) over the time of exhaust gas. The results showed that with increasing the engine speeds, the NOX emissions decrease steadily and then increases, which is due to the high temperature in the cylinder. The viscosity and density of fuels have an effect on NOX emission, and because of the larger droplets of the fuel, it released NOX. The highest NOx emissions belong B10 biodiesel in 1400 rpm, due to the high oxygen content of this fuel and the lowest NOx emissions belong B10 biodiesel in 1300 rpm, due to the low density of the fuel compared to diesel. CO is a colorless and odorless gas, whose even very low concentrations are dangerous for humans and animals. The results showed that with increasing the engine speeds, the CO emission decreased and the minimum CO emission for diesel engine is more than the biodiesel-blended that decreased by 37.61% because of excess oxygen availability and complete combustion in biodiesel than diesel.

    Conclusion

    The results of this study showed that the B10 blend in high engine speeds, generally had the best performance and emissions characteristics among the three fuels used in this study. Also, this investigation will assist in the development of WCO biodiesel as a viable sustainable fuel source through the use of a CFD model, optimized engine configuration, and technical report.

    Keywords: Engine characteristics, GT-Power software, Thermodynamic model, Waste cooking oil
  • A. Waismoradi, M. E. Khorasani *, H. Bahrami, S. M. Safieddin Ardebili, H. Zaki Dizaji Pages 575-585
    Introduction

    Today, the number of diesel engines is increasing due to their high efficiency and low greenhouse gases. In the present study, the effect of adding nano cellulose as nanoparticles to diesel fuel on the performance parameters and emissions of diesel engine was investigated. Nano cellulose was provided by the Nano Novin Company in Sari. Nano cellulose values were considered at 3 levels of zero, 25 ppm and 75 ppm. Also, the tests were performed at 3 engine speed of 1600, 2000 and 2400 rpm in full load mode.

    Materials and Methods

    In this study, nanocellulose was used as nanoparticles to add to diesel and to evaluate the performance and emission parameters of the engine. To prevent the deposition of nano cellulose in diesel fuel, jelly type nano cellulose was used. The samples were named after adding different amounts of nano cellulose, abbreviated D100N0, D100N25 and D100N75. D100 means 100% pure diesel and N means different amounts of nano cellulose with different amounts. Ultrasound was used to obtain homogeneous samples. About 3 liters were prepared from each sample so that it could be used for at least 3 repetitions. The required tests were performed at three different speeds of 1600, 2000 and 2400 rpm in full load mode. The necessary equipment was used to measure the performance parameters and air emissions, including diesel engine connected to the dynamometer, emissions measuring device, fuel system and control room (to apply the load and provide conditions for each treatment and data collection). The air-cooled, four-stroke, compression-ignition single-cylinder engine made by the Italian company Lombardini was used. The D400 eddy current dynamometer made in Germany was used. The ability to measure power by this dynamometer is a maximum of 21 hp, a maximum speed of 10,000 rpm and a maximum torque of 80 N.m. To measure of emissions, the MAHA MGT5 emissions meter was used. This device is able to measure the values of CO, CO2, NOX, O2 and UHC.

    Results and Discussion

    The results showed that increasing engine speed in all fuel combinations increased engine power, specific fuel consumption, carbon monoxide and unburned hydrocarbons and decreased torque. Also, increasing the amount of nano cellulose per engine speed increased the amount of power and torque, but reduced the specific fuel consumption, carbon monoxide and unburned hydrocarbons. The amount of NOX increased with increasing engine speed, but at each engine speed the addition of 25 ppm nanocellulose to pure diesel significantly increased the amount of NOX. But at low speed, increasing 75 ppm nanocellulose to pure diesel reduced the amount of NOX.

    Conclusion

    The results of this study showed that the addition of nano cellulose as nanoparticles can improve the performance of diesel engines and also reduce the amount of emissions gases emitted from the engine. The results also showed that increasing 25ppm nanocellulose had a greater effect on engine performance. But to reduce the amount of emissions, 75 ppm nanocellulose was better.

    Keywords: Diesel Engine, nanocellulose, Nitrogen oxides, power
  • H. Mahboub Yangeje, A. Mardani * Pages 587-599
    Introduction

    Seedbed preparation, seeding, and transplanting are usually based on mechanical soil tillage. Tillage by cutting, mixing, overturning, and loosening the soil can modify the physical, mechanical, and biological properties of soil. These days, because of soil protection, the use of tillage tools is less and less recommended, and some implements such as cultivators are preferred to primary tillage tools such as plows. Experimental study of soil-tool interaction and field measurements of the mechanics of tillage tools are usually time-consuming and costly. On the other hand, the variety of variables and uncontrolled conditions add other dimensions to the complexity of this method. Also, the experimental and analytical methods do not have a comprehensive view of stress distribution and soil deformation in the soil-tool interaction process.

    Materials and Methods

    The main purpose of this study is to validate the results of numerical simulations in two phases of experimental tests: in soil bin environment and in finite element computer simulations. Experimental tests were performed in the soil bin environment of the Department of Mechanical Engineering of Biosystems, Urmia University, which has a soil bin facility with dimensions of length and width of 24 and 2 m, respectively, and has clay loam soil. Before experimental tests, soil preparation was performed by using some special tillage implements (harrow, leveler, and roller) which were attached to the soil bin (Figure.1). For experimental tests, a mechanism set consisting of two cultivator blades with a width of 15cm, a length of 20cm, and at a spacing of 35cm from each other was prepared and constructed. The relevant mechanism is designed to have the ability to change the tillage depth. Data were collected at three different soil depth levels of 6, 10, and 14cm in the soil bin with three replications. Data recording was performed using a 10-channel data logger with load cell connectivity and data storage ability. Also, in this study, the Drucker-Prager model as a finite element simulation method was used to calculate the stress during the soil-tool relationship. ABAQUS 6.10.1 software was used to simulate the cultivator tine. To solve the problem, the soil parameters were defined as presented in Table 1, and then the interaction between the soil-tool model and the necessary constraints, including boundary conditions, were defined. In the next step, meshing was applied to the constructed model.

    Results and Discussion

    In the results section, first, the results related to the amount of traction force required for the tillage tine in the simulation were calculated and then compared with the soil bin experimental tests. The traction force of the finite element simulation results for three tillage depths of 6, 10, and 14 cm in three principal directions is shown in Figure 4. A comparison of simulation and experimental results showed that there is a good agreement between them. In comparison, the simulation error range of the three depths of 6, 10, and 14 cm has shown 7.3, 5.6, and 4.16% at a speed of 2.5 kmh-1, respectively, as the velocity studied in this research. In the next section, the results of stress distribution contours in the soil and finally the overlap of the blade effect were discussed. Figure 6 shows the status of stress contours at three depths. By increasing the depth of the tine at the three depth levels studied, the stress range is shifted from the soil surface to its depth. For this purpose, at the maximum depth studied in this study (14 cm), it shows that the stress propagation to the soil surface is less than at other depths. Also, with decreasing depth, for a depth of 6 cm, the maximum stress was on the top soil surface, in other words, more deformation was seen on the soil surface.

    Conclusion

    Comparing the simulation results for predicting traction force with the results of experimental tests has led to relatively acceptable results and the maximum traction force prediction error at different depths has been about 7.3%.The distribution of stress in the soil was observed due to the tine depth. The highest intensity of stress propagation was observed at the soil surface; and the highest soil surface deformation at a depth of 6 cm. With increasing depth, both parameters of stress and soil surface deformation have decreased. According to the results of the studied blades, it is better to use these types of tillage tools only at lower depths. Also, in evaluating the overlap of the soil loosening zone in the side-by-side tines, it proves the superiority of the tine performance at lower depths.

    Keywords: Chisel plow, finite element method (FEM), Soil bin, soil- tine interaction
  • A. Heydarian, E. Ahmadi *, F. Dashti, A. Normohammadi Pages 600-612
    Introduction

    The quick deterioration of fruit and vegetables has led researchers to find a solution to increase the shelf life. Foodstuff packaging is a vital technology to maintain freshness, prevent deterioration, and physiological and mechanical damages, and increase the shelf life of fresh products. Employing various post-harvest technologies prevent light, heat, and humidity transmission and control the microorganism activity, thereby reducing the cost and maintaining the quality of fresh and processed products during storage. Fresh okra has a shelf life of 10 days and is stored at 1-10°C due to high respiration rate and moisture loss. Today, the use of nanotechnology in the packaging industry is developed and expanded. The aim of the packaging is to increase the shelf life and prevent bacterial and shipping damages, as well as control the humidity and gases transmission, thereby reducing food spoilage. Modified atmospheric packaging (MAP) is one of the famous methods for increasing the shelf life of fresh products in which the aging process is reduced by increasing CO2 and decreasing. Decreasing the respiration rate, producing ethylene, and metabolic reactions in the modified atmosphere lead to a reduction in product deterioration. The use of coatings and edible films is being increased in order to maintain sensitive features like flavors, fragrances, and the appearance of different products and increase the shelf time of fruits and vegetables. Chitosan edible coating is a non-fragrance and non-flavor polysaccharide with a high molecular weight that is widely used because of its antifungal, biological, and biochemical properties. Chitosan is a natural polymer obtained from chitin, which is abundantly found in crustacean shells. The aim of the present study is to evaluate the effect of packaging films and chitosan coating under the modified atmosphere storage condition on qualitative and quantitative parameters of okra during storage.

    Materials and Methods

    The process of present research was performed in the Laboratory of Mechanical Properties and Rheology of the Biosystem Engineering Department, Faculty of Agriculture, Bu-Ali Sina University, Hamedan, in 2016. Okra cv. Kano Dwarf was selected due to its short post-harvest life and provided by farms in Kermanshah Province. Okras were handpicked and they were free of any spots, contamination, or decay, with the almost same size and shape, without any mechanical and microbial damage. The treatments of the present study were chitosan covering, modified atmosphere by a gas mixture of 5% O2 + 10 CO2 + 85% N2, three types of packaging films including silicone nano-emulsion (Nano Bespar Aytak Co.), nano-polyethylene, and light polyethylene (LFO200), as well as two temperature levels of 1 ± 4°C (refrigerator) and 1 ± 25°C (room temperature). The influence of modified atmospheric treatments, chitosan coatings, and packaging films at two storage temperatures on chemical factors (pH and TSS) and mechanical properties including shear stress (TB), shear force (FB), shear modulus (GK) were evaluated at the end of 12 days of storage in a completely randomized design with a factorial experiment in three replications on Okra.

    Results and Discussion

    Among the films used, silicon nano emulsion film and chitosan coating were more able to maintain TSS. The pH value decreased due to the control of respiratory rate and corruption under modified atmospheric conditions. The mechanical properties of the samples showed that the shear stress changes of the coated sample were significantly less than the untreated ones compared to the beginning of the maintenance period. The sample stored at 4°C had less shear force during the storage period than similar specimens at 25°C. The modified atmosphere caused the shear modulus to decrease with increasing storage time compared to the beginning of the storage period.

    Conclusion

    The results of the present research revealed that silicon nano-emulsion film has a higher capability in preserving the qualitative and quantitative properties of okra compared to other studied films. Between the two studied temperatures, 4°C storage temperature had better performance in preserving qualitative and quantitative properties of the okra compared to 25°C. The controlled atmosphere increases okra's shelf life due to reduced respiration rate. In general, maintenance of the products in a modified atmosphere package preserves the quality of the products and extends their shelf life.

    Keywords: Chitosan, modified atmosphere, Nano packaging film, Okra
  • H. Amiri, A. Asakereh *, M. Soleymani Pages 613-626
    Introduction

    Wheat, is the most important crop in the world. In Iran, wheat is the most important and strategic agricultural crop, due to its vital role in providing food and feeding livestock. Because wheat harvesting operation has a significant share of total grain losses, it is considered as the most important and sensitive stage of production. Recently, in Iran, the need for straw to feed livestock has increased sharply, and since wheat is the main source of straw production, changes have been made in the configuration of the grain combine harvester so that in addition to collecting grain, it can crush and collect straw. These combine harvesters are known as straw collecting combine harvesters. The growing need for straw, along with the high cost and difficulty of straw collecting, has made straw collecting combine harvesters more popular, especially in areas where animal husbandry is common alongside agriculture. Despite facilitating and increasing the possibility of straw collection by this type of combine harvesters, in many cases grain losses have increased. Therefore, it is necessary to investigate the amount of grain losses in this type of combine harvester and determine the factors affecting its losses.

    Materials and Methods

    This study was conducted to investigate the effect of ground speed and wheat yield on grain loss in a straw collecting combine harvester. The use of this type of harvester was also analyzed economically. Two models of JD-1055 and JD-1165 combine harvesters were considered for evaluation. The experiments were performed in a split factorial design in the form of a randomized complete block design. Grain yield (at three yield levels: less than 2 Ton ha-1, 2 to 5 Ton ha-1, and more than 5 Ton ha-1) was the main factor and the other two treatments, the model of combine harvester and the ground speed (with three levels: 1, 1.5 and 3 km h-1) were factorially placed in subplots. Loss components including head loss, combine harvester body loss, end loss, threshing unit loss, cleaning unit loss, and quality losses were measured and compared with that of a conventional grain combine harvester. Field capacity and harvesting cost were also measured for both types of combine harvesters. Finally, based on cost-benefit analysis, the straw collecting combine harvester was compared with the conventional combine harvester economically.

    Results and Discussion

    The results showed that in addition to the main effects, the two-way and three-way interactions were also significant for the studied factors on head loss, body loss, end loss, threshing unit loss, cleaning unit loss, and quality losses of straw collecting combine harvester. The losses of the straw collecting combine harvester are strongly affected by the ground speed and the grain yield. The percentage of grain loss in low yields (less than 2 Ton ha-1) was significantly higher than that of medium (2 to 5 Ton ha-1) and high yields (more than 5 Ton ha-1). The average loss of JD-1055 was less than JD-1165, mainly because of more loss in threshing and cleaning units. The highest total losses, with a rate of 10.54%, were related to JD-1165 in low yields, while the lowest percentage of total losses, at a rate of 2.54%, was related to JD-1055 in medium grain yield and low speed(1 km h-1). The total grain losses of conventional combine harvesters obtained about 3.22% while the total grain losses of straw collecting combine harvesters were approximately 5.44%. In general, the losses of straw collecting combine harvester were about 2.22% more than that of the conventional combine harvester. The economic evaluation showed that in the region where animal farming is common along with agriculture, the use of straw collecting combine harvester is more economical than a conventional combine harvester.

    Conclusion

    Combine harvester model, grain yield, as well as ground speed of the combine harvester affects the grain losses in different units of a straw collecting combine harvester as well as total losses. As the grain yield and the feed rate increase, the total losses of this combine decrease at first but increase again in high yields. Adjusting the feed rate helps reduce the end losses and total losses of straw collecting combine harvester. In the study area, using a straw collecting combine harvester is more economical than a conventional combine harveste

    Keywords: Economic Evaluation, Quality loss, Straw, Wheat yield