Girma Gebresenbet

Scoring system for evaluating the stress to cattle of commercial loading and unloading.

The loading and unloading of cattle for road transport is stressful but the stress is difficult to evaluate in terms of the welfare of the cattle. Over one year, 40 normal commercial journeys in northern Spain were analysed in terms of time limits and behavioural events in order to design an objective method for assessing the stresses imposed on the animals, and a scoring method was developed for assessing the welfare of the animals during loading and unloading. Several definitions of time intervals were assessed to calculate a time score per animal, and easily observable behavioural events were scored and combined with the time score to obtain a total loading/unloading score. More than half of the loadings and unloadings involved turns, slips and vocalisations. Mounts and bouts of fighting were infrequent and balks and falls were significantly more frequent during loading than unloading. The plasma concentrations of cortisol, glucose and lactate, the activity of creatine kinase and the pH of the meat 24 hours after the animals were slaughtered were also measured. The results indicated that loading was more stressful than unloading and that higher scores implied significantly higher levels of stress.

Effect of transport time and ageing on aspects of beef quality

Forty-eight bulls were transported by road in groups of eight for approximately 30 min, 3 or 6 h in two replicates. After slaughter, steaks from the longissimus dorsi thoracis of all transported animals were analysed in terms of pH, water-holding capacity, myoglobin concentration, texture at 7 and 14 days of ageing (compression and Warner-Bratzler analyses) and colour of the same surface of meat cut at 24 h post-mortem and allowed to bloom for 24 h and 7 d (L(∗)a(∗)b(∗), chroma and hue). The myofibrillar resistance of the meat from animals transported 30 min was significantly greater at 20% compression (P<0.05). The maximum load and a(∗)b(∗) and chroma were all lower for meat aged 14 days.

Effect of transport time on sensorial aspects of beef meat quality

Forty-eight slaughter bulls were transported by road in groups of eight for approximately 30 min, 3 h and 6 h in two replicates. After slaughter and an ageing time of 7 days, steaks from the longissimus dorsi thoracis were tasted by a trained sensory panel in terms of odour, tenderness, residue, juiciness, flavour intensity, flavour quality, and overall liking. Transport time had a significant effect (P<0.05) on meat tenderness and overall liking. The panel preferred meat from animals given the 3-h journey as opposed to the 30 min or 6-h journey and found it was more tender and had a better overall liking.

Characterization of municipal waste in Kampala, Uganda

In Kampala, Uganda, about 28,000 tons of waste is collected and delivered to a landfill every month. Kampala Capital City Authority (KCCA) records show that this represents approximately 40% of the waste generated in the city. The remaining uncollected waste is normally dumped in unauthorized sites, causing health and environmental problems. However, the organic fraction of domestic waste can provide an opportunity to improve livelihoods and incomes through fertilizer and energy production. This study characterized the municipal waste generated in Kampala and delivered to Kiteezi landfill between July 2011 and June 2012, that is, covering the dry and wet months. On each sampling day, waste was randomly selected from five trucks, sorted and weighed into different physical fractions. Samples of the organic waste from each truck were analyzed for total solids, major nutrients, and energy content. During the wet months, the waste consisted of 88.5% organics, 3.8% soft plastics, 2.8% hard plastics, 2.2% paper, 0.9% glass, 0.7% textiles and leather, 0.2% metals, and 1.0% others. During the dry months, the waste consisted of 94.8% organics, 2.4% soft plastics, 1.0% hard plastics, 0.7% papers, 0.3% glass, 0.3% textile and leather, 0.1% metals, and 0.3% others. The organic waste on average had a moisture content of 71.1% and contained 1.89% nitrogen, 0.27% phosphorus, and 1.95% potassium. The waste had an average gross energy content of 17.3 MJ/kg. It was concluded that the organic waste generated can be a suitable source of some plant nutrients that are useful especially in urban agriculture. Implications: The result of the waste characterization in Kampala was found to be significantly different from that obtained for other Sub-Saharan African (SSA) cities, showing that studies assuming average values for the waste fractions are likely to result in erroneous results. Furthermore, no reduction in organic fraction of the waste was noticed when compared with a study done two decades ago in spite of greatly improved economic status of Kampala city, a finding that is not in agreement with several other similar studies done for other SSA cities.

Performances of seed drill coulters in relation to speed, depth and rake angles

The horizontal and vertical soil forces acting on coulters with rake angles of 70, 90, 110 and 130 ° and widths of 15 and 40 mm were measured to investigate the variation of working depth under various conditions. The measurements were made with extended octagonal ring transducers using speeds between 0·3 and 3·0 m/s and depths down to 70 mm both in dry sand in the laboratory and down to 45 mm in a clay field. Polynomials in one variable and in several variables were fitted to the measured data using statistical analysis. The relationship of force to speed was well described by a second-order polynomial. The quadratic term contributed far more to the fit of the model than the linear term. The relationship of force to depth was described by a second-order polynomial, but this polynomial had its intercept at the origin. Polynomials in the three variables rake angle, speed and depth were also fitted. These polynomials were used to investigate the influence of coulter and suspension parameters upon the variation in equilibrium depth when the coulter is subjected to varying working conditions. In sandy soils the variation in equilibrium depth decreased with increasing rake angle, while the influence of the suspension parameters was small.

Reverse logistics system and recycling potential at a landfill: A case study from Kampala City.

The rapid growing population and high urbanisation rates in Sub-Saharan Africa has caused enormous pressure on collection services of the generated waste in the urban areas. This has put a burden on landfilling, which is the major waste disposal method. Waste reduction, re-use and recycling opportunities exist but are not fully utilized. The common items that are re-used and re-cycled are plastics, paper, aluminum, glass, steel, cardboard, and yard waste. This paper develops an overview of reverse logistics at Kiteezi landfill, the only officially recognised waste disposal facility for Kampala City. The paper analyses, in details the collection, re-processing, re-distribution and final markets of these products into a reversed supply chain network. Only 14% of the products at Kiteezi landfill are channeled into the reverse chain while 63% could be included in the distribution chain but are left out and disposed of while the remaining 23% is buried. This is because of the low processing power available, lack of market value, lack of knowledge and limited value addition activities to the products. This paper proposes possible strategies of efficient and effective reverse logistics development, applicable to Kampala City and other similar cities.

Comparative analysis of the field performances of a reversible animal-drawn prototype and conventional mouldboard ploughs pulled by a single donkey

Abstract The performance of two conventional animal-drawn mouldboard ploughs and a reversible prototype mouldboard plough were studied under field conditions in Kenya on previously ploughed and harrowed clay nitisol. The two mouldboard ploughs were a Victory plough, manufactured in the United Kingdom, and a cylindrical mouldboard plough manufactured by the Rumptstad factory of The Netherlands. The reversible prototype wooden mouldboard plough was developed at the Department of Agricultural Engineering of the Swedish University of Agricultural Sciences as a mouldboard type, modernized version of the ard type plough. Simultaneous and dynamic measurement of forces, moments, ground speed and tillage depth were made. The results of the comparison between the three ploughs showed that both the horizontal and vertical components of forces resulting from the reversible plough were about 50 and 65% of the forces resulting from the Rumptstad and the Victory ploughs, respectively. In the case of the reversible plough, the effect of a tail angle on horizontal and vertical forces was investigated. The results of field tests confirmed the laboratory results in that the form of graphs and equations describing the relationship between the forces and tail angle were similar to those obtained during the laboratory tests. A single donkey was used to draw the implements throughout the experiment. It pulled about 25% of its body weight at an average speed of 0.8 m s −1 and worked for 9 h per day.

Mapping out the solid waste generation and collection models: The case of Kampala City

This paper presents a mapping of the waste collection systems in Kampala city, using geographical information system (GIS) ArcGIS mapping software. It discusses the existing models of waste collection to the final disposal destinations. It was found that food and yard wastes constitute 92.7% of the waste generated in Kampala. Recyclables and other special wastes constitute only 7.3% of the total waste, mainly because of the increased level of reuse and recycling activities. The generation rate of solid wastes was on average, 582, 169, 105, and 90 tons/day from poor areas, upscale wealthier areas, business centers, and market areas respectively. This tonnage of waste was collected, transported, and disposed of at the city landfill. The study found that in total, residential areas of poor people generate more waste than other categories stated earlier, mainly because of their large populations. In total, there were 133 unofficial temporary storage sites acknowledged by Kampala Capital City Authority (KCCA) but not formally designated, 59 illegal dump sites, and 35 officially recognized temporary waste storage locations. This paper presents large-scale data that can help with understanding the collection models and their influence on solid waste management in Kampala city, which could be used for similar cities in developing countries. Implications: The rapid urban population growth in Kampala City has increased the generation of waste, making it impossible for the municipal authority to manage the waste effectively due to limited financial resources. All this, coupled with the declining landfill capacities and rising real costs of disposal, has attracted the attention of the growing population, yet the health and sustainability of the environment have to be guaranteed.

Cleaning of harvested Norway spruce stumps using a vibration-based method

With the increasing demand for renewable energy in Sweden and Finland, interest in using softwood stumps as biofuel is growing. The major drawback to using these energy-rich stumps as biofuel is the presence of contaminants, which lead to high ash content and thereby lower technical feasibility and value as fuel. To reduce contaminant levels, stumps are normally shaken during extraction, but this process is time-consuming. It is also frequently inadequate, necessitating storage for further cleaning for long periods usually exceeding one year, which can lead to high dry-matter losses. Faster and more effective cleaning methods are therefore highly desirable. A vibration-based method for cleaning, as often used in other industrial sectors, could offer a solution. The reduction in contaminants on stumps harvested from two different soil types was tested using a grid-fitted test-rig bench which could be vibrated in one or three dimensions. The vibration was performed at settings from 1.33 g to 6.15 g. Ash content was reduced by 50% of the initial value after 30 seconds, which in some cases was sufficient to achieve ash content below 4%. The cleaning process was effective regardless of vibration amplitude used or orientation. By employing vibration, clean stumps could be made available as fuel within the same harvesting season. Such rapid removal of stumps would allow prompt site regeneration processes.

Effect of speed on trajectory of penetration of a trailed mouldboard plough

The effect of variation of ploughing speed on the penetration path of a trailed three-furrow mouldboard plough was studied. Experiments were made in two fields of different soil conditions (loosened and moderately compacted). The range of speed used was 0.15–1.6 m s−1. Continuous and simultaneous measurements of speed and depth were performed using a fifth wheel and a linear potentiometer equipped with a wheel running very near the plough bottom, respectively. Results of several field test series revealed that ploughing speed influences appreciably the path of penetration of this type of plough. The penetration curve was found to be described using an exponentially decaying form of equation. The constant which accounts for the penetration trajectory was proportional to ploughing speed. An appreciable effect of variation of soil conditions was also observed.