Oliver Hensel

Oliver Hensel
Universität Kassel · Department of Agricultural Engineering

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302
Publications
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Introduction
Skills and Expertise

Publications

Publications (302)
Article
The energy and exergy based thermal analysis was conducted on a newly developed solar coffee roasting system. The system is comprised of a rotating drum (diameter: 400 mm × length: 400 mm), electric motor with variable frequency drive, cooling tray (diameter: 500 mm × height: 100 mm), fan blower, and coupled with a heating source i.e., Scheffler fi...
Article
Full-text available
This paper seeks to investigate the potential use of laser-based imaging techniques in non-invasive quality inspection of apple slices during drying. For this purpose, Laser-light Backscattering (LLBI) and Biospeckle (BSI) Imaging techniques were investigated. Images at 980 nm and 1450 nm were captured. The data was used to develop Gaussian Process...
Article
Latent heat thermal storage (LHTS) using phase change materials (PCMs) has been successfully adapted in various fields but its use in agriculture has remained very limited mainly involving solar dryers and greenhouses. This study aims to develop a standalone application flexible LHTS system capable of storing and supplying solar thermal energy to v...
Article
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Currently, an estimated 20% of the population in Sub-Saharan Africa is food insecure with the incidence of hunger and malnutrition still rising. This trend is amplified by the socioeconomic consequences of the COVID-19 pandemic. In contrast, more than a third of the harvestable perishable produce is lost due to a lack of preservation or failure to...
Article
Current global climate change mitigation programs have been unable to meet the Paris Agreement's targets, and Ghana's situation is no exception. There is, therefore, an increased need for intensification of renewable energy deployment programs with an emphasis on solar energy as it constitutes about 90% of Ghana's installed renewable energy generat...
Conference Paper
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In smart drying process, a digital replica of the process operation is created via sensors (so-called Digital Twin) to optimize the drying conditions. To create a digital twin of the drying process, there are various measurements to take into consideration among which moisture content. In what follows, LED and LLBI imaging were studied at 1450 nm....
Article
Full-text available
Energy and exergy based thermal analysis was conducted for a solar assisted yogurt processing unit capable of performing required heating and cooling processes in a single container. The system consisted of a round-shaped fermentation chamber connected with a hot water storage tank coupled with an evacuated tube collector and a pillow plate at the...
Article
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Solar-based milk pasteurization enables decentralized maintenance of milk in remote areas of developing countries like Pakistan. Two innovative and efficient medium temperature range solar techniques; solar concentrator (SC) and evacuated tube collectors (ETC) were employed and compared based on theoretical and experimental analyses for an expedien...
Article
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Potato chips production is a traditional food process. To achieve uniform product quality, raw materials are usually rigorously sorted. Traditionally, the process is conducted in a single stage approach leading to high quality losses. Recently, dynamically optimized frying processes have been found to result in higher product quality. Consequently,...
Article
Full-text available
Solar-based milk pasteurization enables decentralized maintenance of milk in remote areas of developing countries like Pakistan. Two innovative and efficient medium temperature range solar techniques; solar concentrator (SC) and evacuated tube collectors (ETC) were employed and compared based on theoretical and experimental analyses for an expedien...
Article
Full-text available
Solar-based milk pasteurization enables decentralized maintenance of milk quality, particularly in remote areas of developing countries. With the introduction of innovative and efficient medium temperature solar technologies, two approaches stand out; solar concentrator (SC) and evacuated tube collectors (ETC) for expedient and efficient milk paste...
Article
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In Pakistan, groundwater resources are depleting at an alarming rate due to intensive pumping, shifting of cropping patterns, and climate change vulnerability. The present study is aimed at investigating groundwater stress in the command area of Lower Chenab Canal (LCC) and associated branch canals. Groundwater stress is determined by considering t...
Article
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The covering of potash tailings piles with technosols (artificial soils) is a modern and promising method for decreasing the saline drainage of these piles. In this context, it is important to determine whether technosols have appropriate physical properties for crop growth. In evapotranspiration covers, physical properties, such as bulk density, p...
Article
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Yogurt production at the farm level is important for adding value to milk. In this study, a solar-assisted yogurt processing unit capable of performing the three processes of heating, fermentation, and cooling in a single unit was developed. It consisted of a circular chamber surrounded by a coil for heating by a solar vacuum tube collector and a p...
Article
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Plant-sourced food has a crucial role in the human food supply as the source of calories and many valuable micronutrient compounds that enhance a balanced and healthy lifestyle. However, a portion of food intended for human consumption produced globally become wastage per year because of a lack of proper processing and preservation technologies. Dr...
Article
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Post-harvest losses are a significant problem worldwide, leading to a waste of resources when they are becoming scarcer. Rather than putting more energy into increasing production volume, addressing post-harvest losses can increase food availability without increasing yields. Using maize in Ethiopia to introduce gendering post-harvest loss research...
Article
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Weeds compete with crops for water, nutrients, and light consequently, have adverse effects on the crop yield and overall productivity. Mechanical weeding is the most common non-chemical method for weed control, which is applied in organic farming, and the weed cultivator is the most common implement in mechanical weeding. This study aimed to desig...
Article
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Digital farming approach merges new technologies and sensor data to optimize the quality of crop monitoring in agriculture. The successful fusion of technology and data is highly dependent on the parameter collection, the modeling adoption, and the technology integration being accurately implemented according to the specified needs of the farm. Thi...
Article
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About 70% of the harvested coffee is exported to the industrialized nations for value addition due to lack of processing and logistic facilities in developing coffee producer countries, thus leaving behind a marginal economic return for the growers. This research was conducted to investigate the roasting capacity of an innovatively developed batch-...
Article
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In tomato drying, degradation in final quality may occur based on the drying method used and pre drying preparation. Hence, this research was conducted to evaluate the effect of different pre-drying treatments on physicochemical quality and drying kinetics of twin-layer-solar-tunnel-dried tomato slices. During the experimental work, tomato slices o...
Article
The objective of this paper was to evaluate the performance of Partial Least Square Regression (PLSR) model and to assess the statistical agreement between two different measurement techniques i.e. Vis‐NIR hyperspectral imaging (HSI) and standard laboratory methods for quality evaluation of dried carrots throughout the hot‐air drying process. Carro...
Article
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Freshwater is essential for irrigation and the supply of nutrients for plant growth, in order to compensate for the inadequacies of rainfall. Agricultural activities utilize around 70% of the available freshwater. This underscores the importance of responsible management, using smart agricultural water technologies. The focus of this paper is to in...
Article
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The state-of-the-art technique to control slug pests in agriculture is the spreading of slug pellets. This method has some downsides, because slug pellets also harm beneficials and often fail because their efficiency depends on the prevailing weather conditions. This study is part of a research project which is developing a pest control robot to mo...
Article
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Digitalization has impacted agricultural and food production systems, and makes application of technologies and advanced data processing techniques in agricultural field possible. Digital farming aims to use available information from agricultural assets to solve several existing challenges for addressing food security, climate protection, and reso...
Article
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Solar-based milk pasteurization enables decentralized maintenance of milk in remote areas of developing countries like Pakistan. Two innovative and efficient medium temperature range solar techniques; solar concentrator (SC) and evacuated tube collectors (ETC) were employed and compared based on theoretical and experimental analyses for an expedien...
Article
Full-text available
Highlights Solar-based milk pasteurization enables decentralized maintenance of milk quality, particularly in remote areas of developing countries. Study for milk quality processed with solar technologies. Payback period calculation for indigenous machines. Comparative prices analysis of available commercially packed milk with solar process milk....
Article
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Many activities from livestock husbandry contribute to emission and concentration of carbon dioxide (CO 2 ), nitrous oxide (N 2 O) and methane (CH 4 ) gases to the atmosphere; activities such as grazing, manure and urine deposited or stored on land as well as crop farming practices such as tilling, burning of biomass or crop residues. A better unde...
Article
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Post-harvest loss is a serious issue to address challenge of food security. A solar-grid hybrid cold storage system was developed and designed for on-farm preservation of perishables. Computational Fluid Dynamic analysis was performed to assess airflow and temperature distribution inside the cold chamber. The system comprises a 21.84 m3 cubical col...
Article
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Background: Development of complementary foods by mixing plant-based (cereals, pulses, oilseeds, and others) ingredients and employing various processing techniques is widely reported. However, information on comparison of anti-nutritional factors and functional properties of extruded and unextruded complementary flours made from a multi-mix is lim...
Article
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Mechanical damages of sugar beet during harvesting affects the quality of the final products and sugar yield. The mechanical damage of sugar beet is assessed randomly by operators of harvesters and can depend on the subjective opinion and experience of the operator due to the complexity of the harvester machines. Thus, the main aim of this study wa...
Article
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This study presents a methodological framework for auditing, optimization as well as the integration of hybridized solar energy in Ghana’s agro-industrial sector. The Functional Analysis System Technique was introduced for systematically translating plant-wide energy requirements into detailed functional and performance design criteria for energy e...
Article
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In this study, hyperspectral imaging (HSI) and chemometrics were implemented to develop prediction models for moisture, colour, chemical and structural attributes of purple-speckled cocoyam slices subjected to hot-air drying. Since HSI systems are costly and computationally demanding , the selection of a narrow band of wavelengths can enable the ut...
Conference Paper
Full-text available
Cocoyam is a root crop grown in the tropical and subtropical regions of the world for food. The crop is valued for its starchy corm and micronutrient composition of minerals, vitamins and bioactive compounds. Hot air drying of the starchy corm is commonly practised for preservation and value addition. However, hot air drying substantially changes t...
Article
Development of an online quality assurance method based on acoustic emissions using magnetic pulse welding Reliable magnetic pulse welding and easy-to-implement process monitoring is essential for the implementation of modern joining processes in the industrial environment. Ideally, the quality of the joint is already predicted during the joining...
Poster
Women in rural communities are at the forefront of harsh economic impacts. Women take care of the home and are entrusted with household food and nutrition requirements. If equipped with the right resources such as sufficient income, women work to make sure their families are food secure. To this end, rural women engage in entrepreneurial activities...
Article
Drying behavior and instrumental color development of beef slices untreated or pretreated with salt or salt and vinegar solutions were monitored by determining the moisture content and the color change by measuring CIELAB values during drying at 50, 60, and 70 °C. Time-series hyperspectral imaging (400–1000 nm) was applied with regard to the develo...
Article
Hyperspectral images (400–1700 nm) of apple slices during hot-air drying were acquired. The fusion of spectral data and Gaussian Process Regression (GPR) successfully predicted vitamin C (R-squared = 0.93 and RMSE = 0.57 mg/100 g fresh-weigh), SSC (R-squared ≈ 0.99 and RMSE ≈ 2.47%), moisture content (R-squared ≈ 1 and RMSE = 0.89%), and shrinkage...
Article
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Celeriac is a good source of fibre, trace minerals, and phenolic compounds; it has a pleasant aroma but is a perishable material, prone to discolouration. This research investigated the optimisation of the quality and energy demand in hot-air dried celeriac slices. The experiment utilised the I-optimal design of response surface methodology with 30...
Article
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Background Optimal nutrition during lactation is essential for the well-being of the mother and the infant. Studies have shown that access to nutrient-rich foods during lactation is critical as minimal stores of nutrients can have adverse effects. This study aimed to investigate the diversity, composition, and nutrient adequacy of diets of lactatin...
Article
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Malnutrition and poor complementary feeding are more predominant in rural than urban areas. Yet, little attention has been given to these discrepancies and the use of validated composite index to explore determinants of complementary feeding practices. Hence, this study was aimed at identifying the determinants of appropriate complementary feeding...
Article
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This study aimed to understand the influence of extruded microparticulated whey proteins (eMWPs) and process design in light ice cream processing by evaluating the microstructure and physicochemical properties. The inulin (T1), a commercial microparticulated whey protein (MWP) called simplesse (T2), a combination (T3), as well as eMWPs (as 50% volu...
Article
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The present work aims to improve the understanding of the effect of different drying strategies at varying temperatures on the dynamic drying behaviour and quality of organic products such as carrots using non-invasive measurement techniques. For this purpose, carrot slices of 3 mm thickness were dried under three different strategies namely air te...
Article
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The objective of this experimental study was to evaluate the effect of twin layer solar tunnel drying on physicochemical quality of tomato slices. The novelty of this dryer is that it has two layers of trays unlike Hohenheim solar tunnel dryer which makes it to have drying capacity of more than two times compare to type hohenheim solar tunnel dryer...
Article
Hohe Aberkennungsquoten stellten in jüngster Zeit ein ernstzunehmendes, ökonomisches Risiko für Pflanzguterzeuger dar. In Feldversuchen konnte gezeigt werden, dass die Verwendung von transferiertem Mulch aus Stroh-oder Gründüngern wie Wicktriticale den Blattlausanflug und damit die Virusbelastung deutlich reduzieren kann.
Article
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The aim of this study was to investigate the influence of raw chicken meat content on the rheological properties and 3D printability of minced meat mixtures using different concentrations of raw and cooked chicken meat. The meat mass contained yolk, crushed ice, lean raw meat and cooked meat with a high concentration of connective tissue. The conce...
Article
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This study investigated the influence of wheat flour substitution with 10-60 % of peeled or unpeeled orange-fleshed sweet potato (OFSP) flour on dough rheological properties as well as the effects of the flour mixture, baking temperature (150-200 oC) and time (15-25 min) on the physical and textural properties of the composite bread. I-optimal (com...
Article
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The European Union funded project SAMS (Smart Apiculture Management Services) enhances international cooperation of ICT (Information and Communication Technologies) and sustainable agriculture between EU and developing countries in pursuit of the EU commitment to the UN Sustainable Development Goal “End hunger, achieve food security and improved nu...
Article
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Orange-fleshed sweet potato (OFSP) flour is rich in health-promoting compounds that can improve the nutritional benefits of baked products when blended with wheat flour. However, the flour particle size and blend proportion may affect the quality properties and consumer acceptability of bakery products. This study investigated the effect of flour p...
Article
In this study drying kinetics of tomato slices at different positions and trays in twin layer solar tunnel dryer was experimentally evaluated. The temperature profile, air humidity, and vapor pressure deficit of the drying air verse time along the length of the dryer at no-load and full load condition were studied. During full load experiment the d...
Article
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Background The storability and eventual quality of flour is influenced by the optimality of the storage conditions. The present study assessed the effect of storage temperature on extruded composite flour packed in different packages. Methods Oats, soybean, linseed and premix (sugar, salt, Moringa & fenugreek) were blended and extruded. The extrud...
Article
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Background Undernutrition among children is a primary concern in sub-Saharan African countries such as Ethiopia. The objective of this paper is to measure the magnitude of undernutrition and associated factors among children under 2 years of age in the Jimma Zone of Southwest Ethiopia. Methods A community-based cross-sectional study with stratifie...
Article
Claw lesions are a serious problem on dairy farms, affecting both the health and welfare of the cow. Automated detection of lameness with a practical, on-farm application would support the early detection and treatment of lame cows, potentially reducing the number and severity of claw lesions. Therefore, in this study, a method was proposed for the...
Article
Stringent regulations on the application and storage of digestate challenge the viability of biogas plants. Current alternatives for reducing the volume of the liquid fraction of digestate include evaporation and membrane processes. For the latter, previous flocculation of solids is required to reduce fouling. In this study, hydrothermal treatment...
Conference Paper
Full-text available
Abstract—Enset fiber is agricultural waste and available in a surplus amount in Ethiopia. However, the hypothesized variation in properties of this fiber due to diversity of its plant source breed, fiber position within plant stem and chemical treatment duration had not proven that its application for the development of composite products is proble...
Article
Highlights Software was developed for estimation of DSSAT CSM-CROPGRO-Soybean cultivar coefficients. Phenology-related coefficients were estimated based on observed phenological events. Growth-related cultivar coefficients were estimated based on time-series observations. Cultivar coefficients were optimized based on single- and multiple-experiment...
Article
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A CSM-CERES-Beet pest damage routine was modified to simulate the impact of Cercospora leaf spot disease effects on sugar beet yield. Foliar disease effects on sugar beet growth and yield were incorporated as daily damage to leaf area and photosynthesis, which was linked to daily crop growth and biomass accumulation. An experiment was conducted in...
Article
Full-text available
In this study, partial least square (PLS) regression models were developed to predict moisture content (MC) (model 1), CIELAB color (model 2) or all four parameters (model 3) of beef slices during drying. Model development was based on data from two measurement campaigns of MC (%), CIELAB L*, a* and b*values and hyperspectral data in the range of 5...