检索结果-南通市图书馆

Development and Fabrication of Manually Push-Pull Type Conical Weeder for Bangladesh Condition

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Agricultural Sciences 2023年第5期14卷 685-709页

作者： Subrata Paul bidhan chandra nath Anwar Hossen Kamruzzaman Pintu Haimonti Paul Sharmin Islam Arafat Ullah Khan Moudud Ahmmed Farm Machinery and Postharvest Technology Division Bangladesh Rice Research Institute Gazipur Bangladesh School of Civil Engineering and Surveying University of Southern Queensland Queensland Australia Workshop Machinery & Maintenance Division Bangladesh Rice Research Institute Gazipur Bangladesh

In Bangladesh, the use of machinery in agriculture production is fast rising. Researchers are developing technology to replace traditional hand weeding to manage weeds in rice fields. The present study has been taken to increase weeding efficiency and reduce the drudgery in weeding and mulching. A line-to-line distance of 20 cm, the operation is push-pull, and field operating condition at 2 - 4 cm standing water (for softening the field) was the designed hypothesis. The weeder consists of a skid/float, float holder, float adjuster, main body frame, rotor, axel, bush, rotor holder, rotor holder adjuster, handle, handle griper, handle holder, handle height adjuster, nut, bolt, etc. The designed weeder was fabricated using MS sheet, MS pipe, MS flat bar, MS nut-bolt, etc. When the rotors perform back and forth, the weeder’s two conical rotors with six plain blades and six serrated blades work together to uproot and bury the weeds. It also contains a 2 mm thick float assembly with a precise angle of 22 degrees. Weeds are uprooted by the weeder’s blades and buried in the muddy soil. It causes topsoil disturbance and enhances aeration. The weeding efficiency and capacity of the conical weeder were 81.92% and 0.0203 ha/h respectively. With a push-pull operation, the weeder can uproot and bury the weeds in a single row at a time. The pushing force and weight of weeder were 43.42 N and 5.6 kg respectively. Farmers can use this weeder to increase their comfort and reduce the drudgery associated with weeding and mulching in their fields.

关键词： Conical Weeder Field Capacity Weeding Efficiency Weed Paddy

Status and Constrain for Mechanization of Rice Harvesting System in Bangladesh

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Agricultural Sciences 2017年第6期8卷 492-506页

作者： bidhan chandra nath Yo-Sang Nam Md. Durrul Huda Md. Mizanur Rahman Panna Ali Subrata Paul Farm Machinery and Postharvest Technology Division Bangladesh Rice Research Institute Gazipur Bangladesh TYM R&D Center Gongju South Korea Entomology Division Bangladesh Rice Research Institute Gazipur Bangladesh

To know the position, problems and suggestion of harvest mechanization of rice, the study conducted in 21 upzillas under seven regions (Dhaka, Mymensingh, Sylhet, Comilla, Bogra, Rajshahi and Rangpur) based on different agro-climatic condition and cropping intensity and 126 farmers participated in the interview. For collecting data, a structured questionnaire was used and statistical analysis of the collected data was carried out. In study area, the average cultivable area was 225 to 1239 decimal (1 decimal = 40 m2) and 97.60% farmer reaping by sickle and only 0.80% used combine harvester. Cut paddy transported by head (13.49%), shoulders (12.7%) or both of them of 11.11% farmer and 44.44% of farmers used small truck or field threshed. Threshing was mainly done using (49.21%) closed drum thresher and open drum thresher (26.20%), likewise 1 of 126 farmer use head-feed combine harvester. The study area, most farmers (37.3%) used kula for the cleaning of rice, but only 8.74% of farmers used winnower. In considerable amount, 80.95% of farmers had machinery, while the remaining (19.05%) did not have machines. Farmers agreed that harvesting was a labor-intensive method (35.71%) and time consuming (28.57%). Transporting of harvested paddy was dangerous and painful for head, shoulder, hand, waist, backbone, leg, etc. With mechanization and the introduction of machinery, 40.48% of farmers identified the main ceiling as the price of the machine and information/lack of credit system (21.43%). In survey area, most farmers (36.51%) identified the vital advantage of mechanized harvesting as lower labor requirement, while 21.43% of farmers said that a lower loss of rice. All farmers who participated in the interview expressed their need for machinery and mentioned agricultural credit with easy terms and conditions, subsidy for buying machinery and the ensuring of a fair market price for their rice.

关键词： Crop Harvesting Mechanization

Design and Development of a Prilled Urea Applicator

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Agricultural Sciences 2021年第5期12卷 530-548页

作者： Subrata Paul Mohammad Abdur Rahman bidhan chandra nath Anwar Hossen A. K. M. Saiful Islam M. Kamruzzaman Milon M. Kamruzzaman Pintu Farm Machinery and Postharvest Technology Division Bangladesh Rice Research Institute Gazipur Bangladesh School of Civil Engineering and Surveying University of Southern Queensland Queensland Australia

A prilled urea applicator was designed and developed to increase fertilizer use efficiency. The developed applicator’s aims to place Urea continuously at the subsurface of soil between two rows of plants. A line-to-line distance of 20 cm, depth of prilled urea placement of 5 - 7 cm, and field operating condition at 1 - 1.5 cm standing water (for softening the field) was the designed hypothesis. At the laboratory and farm level, test the developed applicator. The applicator consists of a rectangular frame, two skids and furrow opener, two cylindrical hoppers, and a drive wheel connected with a metering device. The designed applicator was fabricated using PVC, except the push handled (mild steel). The metering device consists of twelve spikes and is made of a metallic plate to apply the Urea uniformly. The applicator has a furrow opener and closer options. The effective field capacity was 0.13 ha/h with a speed of 1.22 km/h and field efficiency of 98%. Due to the continuous falling mechanism, there is no missing option but found the over-falling urea for both hoppers was found 5.35%. The average depth of urea placement was 6.38 cm. The machine was user-friendly to push, and the mean pushing force was 63.89 N. The weight of the applicator was 9 kg. So, it is natural to carry from one field to another field. The applicator is also convenient to handle, operate and manage.

关键词： Prilled Urea Applicator Deep Placement Urea Use Efficiency Capacity

Texture coefficient and band gap tailoring of Fe-doped SnO_(2) nanoparticles via thermal spray pyrolysis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2022年第4期41卷 1332-1341页

作者： Majibul Haque Babu bidhan chandra Dev Jiban Podder Department of Physics Bangladesh University of Engineering and TechnologyDhaka 1000Bangladesh

An investigation of Fe-doping effect on SnO_(2) thin films was performed in this study using thermal spray pyrolysis(TSP) *** surface morphology and structural,optical and electrical properties were studied by field energy scanning electron microscope(FESEM),X-ray diffraction(XRD),ultraviolet-visible(UV-Vis) spectroscopy and four-point probe *** EM images demonstrate that the surface morphology of the as-deposited films varies when Fe-doping content *** studies reveal that crystallite size and preferential growth orientations of the films are dependent on Fe-doping *** grain size is found to decrease with the increase in Fe *** studies also specify that the films have tetragonal rutile-type structure with mixed secondary *** texture coefficient value of(110) plane increases with the concomitant in-plane(220) decrease in higher doping *** resistivity and the optical absorbance are found to increase with Fe *** direct optical band gap decreases from 3.94 to3.52 eV with increasing Fe content.

关键词： SnO_(2)thin film Thermal spray pyrolysis Texture coefficient Optical band gap

Flexible Covalent Organic Frameworks:Design,Synthesis,and Applications

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

CCS Chemistry 2024年第4期6卷 856-881页

作者： Chunqing Ji Chengjun Kang bidhan chandra Patra Dan Zhao Department of Chemical and Biomolecular Engineering National University of SingaporeSingapore 117585

Structural flexibility is an intriguing characteristic observed in materials that endows them with dynamic properties,allowing for intelligent adaptation and deformation in response to varying *** organic frameworks(COFs),a promising class of crystalline porous polymers,have garnered significant attention due to their unique features,including well-ordered,predesignable,and tunable structures,as well as their light-weighted nature and high thermal/chemical *** flexibility into COFs offers a captivating pathway for developing advanced materials with dynamic properties and versatile *** flexible COF field is currently experiencing rapid expansion,and there is a growing need for systematic review articles that offer a comprehensive overview of the developments in this *** this mini-review,we delve into the factors that contribute to structural flexibility in COFs from the point of structural *** summarize and categorize various modes of achieving flexibility across different dimensions,and discuss the potential applications of flexible COFs in vapor/gas adsorption,sensing,and smart membrane separations;further,we highlight their prospects and future research advancement.

关键词： covalent organic frameworks framework flexibility inducing factors flexibility modes smart materials

Fractional order prey-predator model incorporating immigration on prey:Complexity analysis and its control

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Biomathematics 2024年第5期17卷 285-317页

作者： Md.Jasim Uddin chandra nath Podder Departmentof Mathematics University of Dhaka Dhaka-1000Bangladesh

In this paper,the Caputo fractional derivative is assumed to be the prey-predator *** order to create Caputo fractional differential equations for the prey-predator model,a discretization process is first *** fixed points of the model are categorized *** identify requirements for the fixed points of the suggested prey-predator model's local asymptotic *** demonstrate analytically that,under specific parametric conditions,a fractional order prey-predator model supports both a Neimark-Sacker(NS)bifurcation and a Flip *** present evidence for NS and Flip bifurcations using central manifold and bifurcation *** parameter values and the initial conditions have been found to have a profound impact on the dynamical behavior of the fractional order prey-predator *** the bifurcation parameter is increased,the system displays chaotic *** simulations are shown to demonstrate chaotic behaviors like bifurcations,phase portraits,invariant closed cycles,and attractive chaotic sets in addition to validating analytical *** suggested prey-predator dynamical system's chaotic behavior will be controlled by the OGY and hybrid control methodology,which will also visualize the chaotic state for various biological parameters.

关键词： Prey-predator model Caputo fractional derivative Flip and Neimark-Sacker(NS)bifurcations immigration chaos control numerical simulation

Extraction of locked-up coal by strengthening of rib pillars with FRP--A comparative study through numerical modelling

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2017年第2期27卷 261-267页

作者： Das Arka Jyoti Mandal Prabhat Kumar Ghosh chandra nath Sinha Amalendu CSIR-Central Institute of Mining and Fuel Research Dhanbad 826001India

In some of the coalfields in India, coal seams are only developed but no extraction of pillars is possible due to the presence of surface or sub-surface structures and also non-availability of stowing materials which leads to huge amounts of coal being locked-up underground. Spontaneous heating and fire, accumulation of poisonous gases, severe stability issues leading to unsafe workings and environmental hazards are the major problems associated with the developed coal pillars. So, there is a pressing need for a technology for the mining industry to extract the huge amount of coal locked-up under different constraints. In this study, the locked-up coal is proposed to be extracted by artificially strengthening the rib pillars. The detailed comparative study is carried out to know the increase of extraction percentage of locked-up coal by strengthening the rib pillars with FRP. Extraction methodology is designed and studied through numerical modelling for its stability analysis to evaluate its suitability of application in underground.

关键词： Locked-up coal Confined core Yield criterion Strengthened rib pillar Strain softening

Improvements after mod Quad and triangle tilt revision surgical procedures in obstetric brachial plexus palsy

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

World Journal of Orthopedics 2016年第11期7卷 752-757页

作者： Rahul K nath chandra Somasundaram Texas Nerve and Paralysis Institute

AIM To compare outcomes of our revision surgical operations in obstetric brachial plexus palsy(OBPP) patients to results of conventional operative procedures at other institutions. METHODS We analyzed our OBPP data and identified 10 female and 10 male children aged 2.0 to 11.8 years(average age 6.5 years), who had prior conventional surgical therapies at other clinics. Of the 20 patients, 18 undergone triangle tilt, 2 had only mod Quad. Among 18 patients, 8 had only triangle tilt and 10 had also mod Quad as revision surgeries with us. We analyzed the anatomical improvements and functional modified Mallet statistically before and after a year post-revision *** Pre-revision surgery average modified Mallet score was 12.0 ± 1.5. This functional score was greatly improved to 18 ± 2.3(P < 0.0001) at least one-year after revision surgical procedures. Radiological scores(PHHA and glenoid version) were also improved significantly to 31.9 ± 13.6(P < 0.001),-16.3 ± 11(P < 0.0002), at least one-year after triangle tilt procedure. Their mean pretriangle tilt(yet after other surgeon's surgeries) PHHA, glenoid version and SHEAR were 14.6 ± 21.7,-31.6 ± 19.3 and 16.1 ± 14.7 *** We demonstrate here, mod Quad and triangle tilt assuccessful revision surgical procedures in 20 OBPP patients, who had other surgical treatments at other clinics before presenting to us for further treatment.

关键词： Revision surgery Obstetric brachial plexus palsy Shoulder movements Joint incongruity Upper limb

Pressure-Induced Instability Characteristics of a Transient Flow and Energy Distribution through a Loosely Bent Square Duct

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy Engineering 2022年第1期119卷 429-451页

作者： Sreedham chandra Adhikari Ratan Kumar Chanda Sidhartha Bhowmick Rabindra nath Mondal Suvash chandra Saha Department of Mathematics Jagannath UniversityDhaka1100Bangladesh School of Mechanical and Mechatronic Engineering University of Technology SydneyNew South WalesAustralia

Due to widespread applications of the bent ducts in engineering fields such as in chemical,mechanical,bio-mechanical and bio-medical engineering,scientists have paid considerable attention to invent new characteristics of fluid flow in a bent duct(BD).In the ongoing study,a spectral-based numerical technique is applied to explore flow characteristics and energy distribution through a loosely bent square duct(BSD)of small *** is accelerated due to combined action of the non-dimensional parameters;the Grashof number Gr(=1000),the curvatureδ(=0.001),and the Prandtl number Pr(=7.0)over a wide domain of the Dean number 0

关键词： Square-shaped duct curvature secondary flow energy distribution chaos