Poljoprivredna tehnika最新文献_第2页

Performance of hybrid photovoltaic/thermal crop dryer in hot humid Nigerian region 光伏/热能混合作物干燥机在尼日利亚湿热地区的性能

Poljoprivredna tehnika Pub Date : 2019-06-04 DOI: 10.5937/POLJTEH1902056U

Sampson Uzoma, N. Nwakuba, Kelechi E. Anyaoha

{"title":"Performance of hybrid photovoltaic/thermal crop dryer in hot humid Nigerian region","authors":"Sampson Uzoma, N. Nwakuba, Kelechi E. Anyaoha","doi":"10.5937/POLJTEH1902056U","DOIUrl":"https://doi.org/10.5937/POLJTEH1902056U","url":null,"abstract":"This paper presents a study carried out to investigate the performance of a hybrid photovoltaic/thermal crop dryer in hot humid region of Umuagwo-Ohaji in the South-east region of Nigeria, through energy and exergy analyses, drying, electrical and thermal efficiencies, energy utilization and energy utilization ratio, sustainability indicators such as waste energy ratio (WER), sustainability index (SI) and improvement potential (IP). Drying experiments were conducted at varying inlet air temperatures (50, 60 and 70 o C), airflow rates (1.14, 2.29 and 3.43 kgs -1 ) and slice thicknesses (10, 15 and 20 mm) on 500g batch size of red pepper slices during sunshine periods. Results obtained show that the total and specific energy consumption for drying a batch of sliced red pepper samples varied between 2.08 – 34.91kJ and 7.04 – 62.76 kJkg -1 , respectively. The energy utilization and energy utilization ratio during the drying process ranged from 195.75 – 3013.21 Js -1 and 1.82 – 20.4%, respectively. The energy and exergy efficiencies varied between 15.6738.17% and 26% to 88%, respectively. The mean drying efficiency of the system ranged from 7.12 – 40.27%. The maximum electrical and thermal efficiencies of 23.86% and 93.03%, respectively were obtained. A waste energy ratio of 0.0827 0.1579 was obtained, whereas SI and IP values ranged between 1.137 ≤ SI ≤ 6.119 and 0.198 ≤ IP ≤0.583kW, respectively. There is certainly a wide range of improvement in the PV/T system as 12.1 – 18.4 % of the solar irradiance was consumed for drying. Prospects for improvement and recommendations for further studies were suggested.","PeriodicalId":281326,"journal":{"name":"Poljoprivredna tehnika","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117345197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Modern fleet management systems 现代车队管理系统

Poljoprivredna tehnika Pub Date : 2019-06-04 DOI: 10.5937/POLJTEH1902023M

Branko Miletić, Đorđe Vranješ

引用次数: 0

Research of Claas Lexion 430 harvester exploitation in soya harvest Claas Lexion 430收割机在大豆收获中的应用研究

Poljoprivredna tehnika Pub Date : 2019-06-04 DOI: 10.5937/POLJTEH1902076M

M. Miodragović, I. Mileusnić, M. Balać, Marija Milovanović

引用次数: 0

Mapping treatments of chemical protection in barley production by using the precision agriculture technology 精准农业技术在大麦生产中的化学防护制图处理

Poljoprivredna tehnika Pub Date : 2019-06-04 DOI: 10.5937/POLJTEH1902047P

M. Pajić, S. Oparnica, M. Oljaca, K. Gligorević, M. Drazic, I. Zlatanović, Biljana Bošković

引用次数: 0

Hydraulic symbols - Part Two: Pumps and actuators 液压符号。第2部分:泵和执行器

Poljoprivredna tehnika Pub Date : 2019-06-04 DOI: 10.5937/POLJTEH1902001P

V. Petrović, B Vera Cerović

引用次数: 4

Field performance analysis of a tractor-drawn turmeric rhizome planter 牵引式姜黄根茎种植机的田间性能分析

Poljoprivredna tehnika Pub Date : 2019-06-04 DOI: 10.5937/POLJTEH1902033M

C. Muogbo, A. Gbabo, N. Nwakuba

{"title":"Field performance analysis of a tractor-drawn turmeric rhizome planter","authors":"C. Muogbo, A. Gbabo, N. Nwakuba","doi":"10.5937/POLJTEH1902033M","DOIUrl":"https://doi.org/10.5937/POLJTEH1902033M","url":null,"abstract":"A field performance analysis of a developed prototype tractor-drawn turmeric planter is presented. The experiment was randomized in a factorial design of three planter levels of rhizome lengths (30, 45 and 60 mm) and operational speeds of 8, 10, and 12 kmh -1 . An average mass of 3 kg of wholesome turmeric rhizomes were introduced into the hopper of the planter and planted in 90 m 2 of experimental plot. During field evaluation of the machine, the effective field capacity, field efficiency, missing index, multiple index and planting depth were considered; whereas laboratory tests were conducted to evaluate the planter’s seed rate, percentage rhizome bruise wheel slippage and fuel consumption. Results obtained show that the maximum seed rate was 0.283 th -1 . The maximum percent bruised turmeric rhizome was found to be 30.08%. The mean effective field capacity varied between 0.63 0.96 hah -1 , at operational speeds of 8 and 12 kmh -1 , respectively and 45 mm rhizome length. The mean field efficiency was obtained to be 65.8%. The maximum wheel slippage of 4.37% and fuel consumption of 3.8 lha -1 were obtained at the machine speeds of 8 kmh -1 and 12 kmh -1 , respectively; whereas the minimum wheel slippage of 3.14% and fuel consumption of 2.2 lha -1 were obtained at the machine speeds of 12 kmh -1 and 8 kmh -1 , respectively for the range of the studied turmeric rhizome length. The highest and lowest percentage turmeric rhizome miss index of 35% were recorded for turmeric rhizome length of 30 mm at a speed of 10 kmh -1 and 8 kmh -1 , respectively. An average planting depth of 68 mm was obtained. The numerical optimization approach was adopted to obtain an optimal operational parameters of 12 kmh -1 speed and 45 mm turmeric rhizome grading size with an overall desirability index of 0.73. An economic evaluation was calculated using the principle of payback period which was obtained to be very small (1.64 years) compared to the life of the planter of 17 years. Prospects for future works were suggested.","PeriodicalId":281326,"journal":{"name":"Poljoprivredna tehnika","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129372108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Hydraulic symbols: Part one: General symbols and symbols of measuring instruments and indicators 液压符号。第1部分:测量仪器和指示器的一般符号和符号

Poljoprivredna tehnika Pub Date : 2019-03-29 DOI: 10.5937/POLJTEH1901045P

Dragana Petrović, V. Cerović

{"title":"Hydraulic symbols: Part one: General symbols and symbols of measuring instruments and indicators","authors":"Dragana Petrović, V. Cerović","doi":"10.5937/POLJTEH1901045P","DOIUrl":"https://doi.org/10.5937/POLJTEH1901045P","url":null,"abstract":"Hydraulic power transfer and management systems are widely used in modern agriculture, especially in agricultural engineering and the associated processing industry. They can be very simple, but also extremely complex, when precise matching of the interaction of their components in real time is very difficult to controll and achieve. In addition, the designs of a number of hydraulic components is sufficiently complicated for detailed representation on the corresponding hydraulic installation. In all cases, analyzing the performance characteristics of components and the entire hydraulic system, as well as understanding the structure of the hydraulic system, is of great importance. One of the generally accepted ways to facilitate and speed up these processes is the application of schematic diagrams of hydraulic systems and their subcircuits. Officially, hydraulic symbols are defined by ISO industry standards. Therefore, ideally, all hydraulic schemes should be configured using universal graphic symbols. Unfortunately, this is not always the case in technical practice. Depending on the manufacturer and/or dealer of the hydraulic equipment, the symbols of the associated schemes vary in a smaller or a greater extent. The real reasons for the existence of these differences can only be assumed. According to some authors, companies want their drawings to differ from the hydraulic schema of competitors. Therefore, the most commonly used hydraulic symbols are presented in this paper.","PeriodicalId":281326,"journal":{"name":"Poljoprivredna tehnika","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126680916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

The establishing of agricultural cooperative and their importance for the economy of the Republic of Serbia 农业合作社的建立及其对塞尔维亚共和国经济的重要性

Poljoprivredna tehnika Pub Date : 2019-03-29 DOI: 10.5937/POLJTEH1901031B

Zlata Bracanović, V. Petrović, Branka Grozdanić, D. Borak

引用次数: 0

The convolutional neural networks: Applications in precision agriculture 卷积神经网络:在精准农业中的应用

Poljoprivredna tehnika Pub Date : 2019-03-29 DOI: 10.5937/POLJTEH1901001M

Ivana Medojevic, D. Marković, V. Simonović, Aleksandra Joksimović, Jovana Rosić-Šakota

引用次数: 0

Parameteres of efficiency of machines for seed processing of red clover and alfalfa 红三叶草和紫花苜蓿种子加工机械效率参数

Poljoprivredna tehnika Pub Date : 2019-03-29 DOI: 10.5937/POLJTEH1901010D

D. Djokić, R. Stanisavljević, D. Terzić, J. Milenković, V. Kozlov, R. Koprivica, A. Vuković

引用次数: 2